Dual-layer DECT for multiphasic hepatic CT with 50 percent iodine load: a matched-pair comparison with a 120 kVp protocol.

PubMed

Nagayama, Yasunori; Nakaura, Takeshi; Oda, Seitaro; Utsunomiya, Daisuke; Funama, Yoshinori; Iyama, Yuji; Taguchi, Narumi; Namimoto, Tomohiro; Yuki, Hideaki; Kidoh, Masafumi; Hirata, Kenichiro; Nakagawa, Masataka; Yamashita, Yasuyuki

2018-04-01

To evaluate the image quality and lesion conspicuity of virtual-monochromatic-imaging (VMI) with dual-layer DECT (DL-DECT) for reduced-iodine-load multiphasic-hepatic CT. Forty-five adults with renal dysfunction who had undergone hepatic DL-DECT with 300-mgI/kg were included. VMI (40-70-keV, DL-DECT-VMI) was generated at each enhancement phase. As controls, 45 matched patients undergoing standard 120-kVp protocol (120-kVp, 600-mgI/kg, and iterative reconstruction) were included. We compared the size-specific dose estimate (SSDE), image noise, CT attenuation, and contrast-to-noise ratio (CNR) between protocols. Two radiologists scored the image quality and lesion conspicuity. SSDE was significantly lower in DL-DECT group (p < 0.01). Image noise of DL-DECT-VMI was almost constant at each keV (differences of ≤15%) and equivalent to or lower than of 120-kVp. As the energy decreased, CT attenuation and CNR gradually increased; the values of 55-60 keV images were almost equivalent to those of standard 120-kVp. The highest scores for overall quality and lesion conspicuity were assigned at 40-keV followed by 45 to 55-keV, all of which were similar to or better than of 120-kVp. For multiphasic-hepatic CT with 50% iodine-load, DL-DECT-VMI at 40- to 55-keV provides equivalent or better image quality and lesion conspicuity without increasing radiation dose compared with standard 120-kVp protocol. • 40-55-keV yields optimal image quality for half-iodine-load multiphasic-hepatic CT with DL-DECT. • DL-DECT protocol decreases radiation exposure compared with 120-kVp scans with iterative reconstruction. • 40-keV images maximise conspicuity of hepatocellular carcinoma especially at hepatic-arterial phase.

Implementation of a 5-Minute Magnetic Resonance Imaging Screening Protocol for Prostate Cancer in Men With Elevated Prostate-Specific Antigen Before Biopsy.

PubMed

Weiss, Jakob; Martirosian, Petros; Notohamiprodjo, Mike; Kaufmann, Sascha; Othman, Ahmed E; Grosse, Ulrich; Nikolaou, Konstantin; Gatidis, Sergios

2018-03-01

The aims of this study were to establish a 5-minute magnetic resonance (MR) screening protocol for prostate cancer in men before biopsy and to evaluate effects on Prostate Imaging Reporting and Data System (PI-RADS) V2 scoring in comparison to a conventional, fully diagnostic multiparametric MR imaging (mpMRI) approach. Fifty-two patients with elevated prostate-specific antigen levels and without prior biopsy were prospectively included in this institutional review board-approved study. In all patients, an mpMRI protocol according to the PI-RADS recommendations was acquired on a 3 T MRI system. In addition, an accelerated diffusion-weighted imaging sequence was acquired using simultaneous multislice technique (DW-EPISMS). Two readers independently evaluated the images for the presence/absence of prostate cancer according to the PI-RADS criteria and for additional findings. In a first reading session, only the screening protocol consisting of axial T2-weighted and DW-EPISMS images was made available. In a subsequent reading session, the mpMRI protocol was assessed blinded to the results of the first reading, serving as reference standard. Both readers successfully established a final diagnosis according to the PI-RADS criteria in the screening and mpMRI protocol. Mean lesion size was 1.2 cm in the screening and 1.4 cm in the mpMRI protocol (P = 0.4) with 35% (18/52) of PI-RADS IV/V lesions. Diagnostic performance of the screening protocol was excellent with a sensitivity and specificity of 100% for both readers with no significant differences in comparison to the mpMRI standard (P = 1.0). In 3 patients, suspicious lymph nodes were reported as additional finding, which were equally detectable in the screening and mpMRI protocol. A 5-minute MR screening protocol for prostate cancer in men with elevated prostate-specific antigen levels before biopsy is applicable for clinical routine with similar diagnostic performance as the full diagnostic mpMRI approach.

Quantitative and qualitative comparison of MR imaging of the temporomandibular joint at 1.5 and 3.0 T using an optimized high-resolution protocol

PubMed Central

Spinner, Georg; Wyss, Michael; Erni, Stefan; Ettlin, Dominik A; Nanz, Daniel; Ulbrich, Erika J; Gallo, Luigi M; Andreisek, Gustav

2016-01-01

Objectives: To quantitatively and qualitatively compare MRI of the temporomandibular joint (TMJ) using an optimized high-resolution protocol at 3.0 T and a clinical standard protocol at 1.5 T. Methods: A phantom and 12 asymptomatic volunteers were MR imaged using a 2-channel surface coil (standard TMJ coil) at 1.5 and 3.0 T (Philips Achieva and Philips Ingenia, respectively; Philips Healthcare, Best, Netherlands). Imaging protocol consisted of coronal and oblique sagittal proton density-weighted turbo spin echo sequences. For quantitative evaluation, a spherical phantom was imaged. Signal-to-noise ratio (SNR) maps were calculated on a voxelwise basis. For qualitative evaluation, all volunteers underwent MRI of the TMJ with the jaw in closed position. Two readers independently assessed visibility and delineation of anatomical structures of the TMJ and overall image quality on a 5-point Likert scale. Quantitative and qualitative measurements were compared between field strengths. Results: The quantitative analysis showed similar SNR for the high-resolution protocol at 3.0 T compared with the clinical protocol at 1.5 T. The qualitative analysis showed significantly better visibility and delineation of clinically relevant anatomical structures of the TMJ, including the TMJ disc and pterygoid muscle as well as better overall image quality at 3.0 T than at 1.5 T. Conclusions: The presented results indicate that expected gains in SNR at 3.0 T can be used to increase the spatial resolution when imaging the TMJ, which translates into increased visibility and delineation of anatomical structures of the TMJ. Therefore, imaging at 3.0 T should be preferred over 1.5 T for imaging the TMJ. PMID:26371077

Quantitative and qualitative comparison of MR imaging of the temporomandibular joint at 1.5 and 3.0 T using an optimized high-resolution protocol.

PubMed

Manoliu, Andrei; Spinner, Georg; Wyss, Michael; Erni, Stefan; Ettlin, Dominik A; Nanz, Daniel; Ulbrich, Erika J; Gallo, Luigi M; Andreisek, Gustav

2016-01-01

To quantitatively and qualitatively compare MRI of the temporomandibular joint (TMJ) using an optimized high-resolution protocol at 3.0 T and a clinical standard protocol at 1.5 T. A phantom and 12 asymptomatic volunteers were MR imaged using a 2-channel surface coil (standard TMJ coil) at 1.5 and 3.0 T (Philips Achieva and Philips Ingenia, respectively; Philips Healthcare, Best, Netherlands). Imaging protocol consisted of coronal and oblique sagittal proton density-weighted turbo spin echo sequences. For quantitative evaluation, a spherical phantom was imaged. Signal-to-noise ratio (SNR) maps were calculated on a voxelwise basis. For qualitative evaluation, all volunteers underwent MRI of the TMJ with the jaw in closed position. Two readers independently assessed visibility and delineation of anatomical structures of the TMJ and overall image quality on a 5-point Likert scale. Quantitative and qualitative measurements were compared between field strengths. The quantitative analysis showed similar SNR for the high-resolution protocol at 3.0 T compared with the clinical protocol at 1.5 T. The qualitative analysis showed significantly better visibility and delineation of clinically relevant anatomical structures of the TMJ, including the TMJ disc and pterygoid muscle as well as better overall image quality at 3.0 T than at 1.5 T. The presented results indicate that expected gains in SNR at 3.0 T can be used to increase the spatial resolution when imaging the TMJ, which translates into increased visibility and delineation of anatomical structures of the TMJ. Therefore, imaging at 3.0 T should be preferred over 1.5 T for imaging the TMJ.

Novel SPECT Technologies and Approaches in Cardiac Imaging

PubMed Central

Slomka, Piotr; Hung, Guang-Uei; Germano, Guido; Berman, Daniel S.

2017-01-01

Recent novel approaches in myocardial perfusion single photon emission CT (SPECT) have been facilitated by new dedicated high-efficiency hardware with solid-state detectors and optimized collimators. New protocols include very low-dose (1 mSv) stress-only, two-position imaging to mitigate attenuation artifacts, and simultaneous dual-isotope imaging. Attenuation correction can be performed by specialized low-dose systems or by previously obtained CT coronary calcium scans. Hybrid protocols using CT angiography have been proposed. Image quality improvements have been demonstrated by novel reconstructions and motion correction. Fast SPECT acquisition facilitates dynamic flow and early function measurements. Image processing algorithms have become automated with virtually unsupervised extraction of quantitative imaging variables. This automation facilitates integration with clinical variables derived by machine learning to predict patient outcome or diagnosis. In this review, we describe new imaging protocols made possible by the new hardware developments. We also discuss several novel software approaches for the quantification and interpretation of myocardial perfusion SPECT scans. PMID:29034066

SU-F-I-16: Short Breast MRI with High-Resolution T2-Weighted and Dynamic Contrast Enhanced T1-Weighted Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, J; Son, J; Arun, B

Purpose: To develop and demonstrate a short breast (sb) MRI protocol that acquires both T2-weighted and dynamic contrast-enhanced T1-weighted images in approximately ten minutes. Methods: The sb-MRI protocol consists of two novel pulse sequences. The first is a flexible fast spin-echo triple-echo Dixon (FTED) sequence for high-resolution fat-suppressed T2-weighted imaging, and the second is a 3D fast dual-echo spoiled gradient sequence (FLEX) for volumetric fat-suppressed T1-weighted imaging before and post contrast agent injection. The flexible FTED sequence replaces each single readout during every echo-spacing period of FSE with three fast-switching bipolar readouts to produce three raw images in a singlemore » acquisition. These three raw images are then post-processed using a Dixon algorithm to generate separate water-only and fat-only images. The FLEX sequence acquires two echoes using dual-echo readout after each RF excitation and the corresponding images are post-processed using a similar Dixon algorithm to yield water-only and fat-only images. The sb-MRI protocol was implemented on a 3T MRI scanner and used for patients who had undergone concurrent clinical MRI for breast cancer screening. Results: With the same scan parameters (eg, spatial coverage, field of view, spatial and temporal resolution) as the clinical protocol, the total scan-time of the sb-MRI protocol (including the localizer, bilateral T2-weighted, and dynamic contrast-enhanced T1-weighted images) was 11 minutes. In comparison, the clinical breast MRI protocol took 43 minutes. Uniform fat suppression and high image quality were consistently achieved by sb-MRI. Conclusion: We demonstrated a sb-MRI protocol comprising both T2-weighted and dynamic contrast-enhanced T1-weighted images can be performed in approximately ten minutes. The spatial and temporal resolution of the images easily satisfies the current breast MRI accreditation guidelines by the American College of Radiology. The protocol has the potential of making breast MRI more widely accessible to and more tolerable by the patients. JMA is the inventor of United States patents that are owned by the University of Texas Board of Regents and currently licensed to GE Healthcare and Siemens Gmbh.« less

Quantitative Analysis of the Effect of Iterative Reconstruction Using a Phantom: Determining the Appropriate Blending Percentage

PubMed Central

Kim, Hyun Gi; Lee, Young Han; Choi, Jin-Young; Park, Mi-Suk; Kim, Myeong-Jin; Kim, Ki Whang

2015-01-01

Purpose To investigate the optimal blending percentage of adaptive statistical iterative reconstruction (ASIR) in a reduced radiation dose while preserving a degree of image quality and texture that is similar to that of standard-dose computed tomography (CT). Materials and Methods The CT performance phantom was scanned with standard and dose reduction protocols including reduced mAs or kVp. Image quality parameters including noise, spatial, and low-contrast resolution, as well as image texture, were quantitatively evaluated after applying various blending percentages of ASIR. The optimal blending percentage of ASIR that preserved image quality and texture compared to standard dose CT was investigated in each radiation dose reduction protocol. Results As the percentage of ASIR increased, noise and spatial-resolution decreased, whereas low-contrast resolution increased. In the texture analysis, an increasing percentage of ASIR resulted in an increase of angular second moment, inverse difference moment, and correlation and in a decrease of contrast and entropy. The 20% and 40% dose reduction protocols with 20% and 40% ASIR blending, respectively, resulted in an optimal quality of images with preservation of the image texture. Conclusion Blending the 40% ASIR to the 40% reduced tube-current product can maximize radiation dose reduction and preserve adequate image quality and texture. PMID:25510772

Independent value of image fusion in unenhanced breast MRI using diffusion-weighted and morphological T2-weighted images for lesion characterization in patients with recently detected BI-RADS 4/5 x-ray mammography findings.

PubMed

Bickelhaupt, Sebastian; Tesdorff, Jana; Laun, Frederik Bernd; Kuder, Tristan Anselm; Lederer, Wolfgang; Teiner, Susanne; Maier-Hein, Klaus; Daniel, Heidi; Stieber, Anne; Delorme, Stefan; Schlemmer, Heinz-Peter

2017-02-01

The aim of this study was to evaluate the accuracy and applicability of solitarily reading fused image series of T2-weighted and high-b-value diffusion-weighted sequences for lesion characterization as compared to sequential or combined image analysis of these unenhanced sequences and to contrast- enhanced breast MRI. This IRB-approved study included 50 female participants with suspicious breast lesions detected in screening X-ray mammograms, all of which provided written informed consent. Prior to biopsy, all women underwent MRI including diffusion-weighted imaging (DWIBS, b = 1500s/mm 2 ). Images were analyzed as follows: prospective image fusion of DWIBS and T2-weighted images (FU), side-by-side analysis of DWIBS and T2-weighted series (CO), combination of the first two methods (CO+FU), and full contrast-enhanced diagnostic protocol (FDP). Diagnostic indices, confidence, and image quality of the protocols were compared by two blinded readers. Reading the CO+FU (accuracy 0.92; NPV 96.1 %; PPV 87.6 %) and the CO series (0.90; 96.1 %; 83.7 %) provided a diagnostic performance similar to the FDP (0.95; 96.1 %; 91.3 %; p > 0.05). FU reading alone significantly reduced the diagnostic accuracy (0.82; 93.3 %; 73.4 %; p = 0.023). MR evaluation of suspicious BI-RADS 4 and 5 lesions detected on mammography by using a non-contrast-enhanced T2-weighted and DWIBS sequence protocol is most accurate if MR images were read using the CO+FU protocol. • Unenhanced breast MRI with additional DWIBS/T2w-image fusion allows reliable lesion characterization. • Abbreviated reading of fused DWIBS/T2w-images alone decreases diagnostic confidence and accuracy. • Reading fused DWIBS/T2w-images as the sole diagnostic method should be avoided.

SU-E-I-57: Evaluation and Optimization of Effective-Dose Using Different Beam-Hardening Filters in Clinical Pediatric Shunt CT Protocol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, K; Aldoohan, S; Collier, J

Purpose: Study image optimization and radiation dose reduction in pediatric shunt CT scanning protocol through the use of different beam-hardening filters Methods: A 64-slice CT scanner at OU Childrens Hospital has been used to evaluate CT image contrast-to-noise ratio (CNR) and measure effective-doses based on the concept of CT dose index (CTDIvol) using the pediatric head shunt scanning protocol. The routine axial pediatric head shunt scanning protocol that has been optimized for the intrinsic x-ray tube filter has been used to evaluate CNR by acquiring images using the ACR approved CT-phantom and radiation dose CTphantom, which was used to measuremore » CTDIvol. These results were set as reference points to study and evaluate the effects of adding different filtering materials (i.e. Tungsten, Tantalum, Titanium, Nickel and Copper filters) to the existing filter on image quality and radiation dose. To ensure optimal image quality, the scanner routine air calibration was run for each added filter. The image CNR was evaluated for different kVps and wide range of mAs values using above mentioned beam-hardening filters. These scanning protocols were run under axial as well as under helical techniques. The CTDIvol and the effective-dose were measured and calculated for all scanning protocols and added filtration, including the intrinsic x-ray tube filter. Results: Beam-hardening filter shapes energy spectrum, which reduces the dose by 27%. No noticeable changes in image low contrast detectability Conclusion: Effective-dose is very much dependent on the CTDIVol, which is further very much dependent on beam-hardening filters. Substantial reduction in effective-dose is realized using beam-hardening filters as compare to the intrinsic filter. This phantom study showed that significant radiation dose reduction could be achieved in CT pediatric shunt scanning protocols without compromising in diagnostic value of image quality.« less

Low-Contrast and Low-Radiation Dose Protocol in Cardiac Computed Tomography: Usefulness of Low Tube Voltage and Knowledge-Based Iterative Model Reconstruction Algorithm.

PubMed

Iyama, Yuji; Nakaura, Takeshi; Yokoyama, Koichi; Kidoh, Masafumi; Harada, Kazunori; Oda, Seitaro; Tokuyasu, Shinichi; Yamashita, Yasuyuki

This study aimed to evaluate the feasibility of a low contrast, low-radiation dose protocol of 80-peak kilovoltage (kVp) with prospective electrocardiography-gated cardiac computed tomography (CT) using knowledge-based iterative model reconstruction (IMR). Thirty patients underwent an 80-kVp prospective electrocardiography-gated cardiac CT with low-contrast agent (222-mg iodine per kilogram of body weight) dose. We also enrolled 30 consecutive patients who were scanned with a 120-kVp cardiac CT with filtered back projection using the standard contrast agent dose (370-mg iodine per kilogram of body weight) as a historical control group. We evaluated the radiation dose for the 2 groups. The 80-kVp images were reconstructed with filtered back projection (protocol A), hybrid iterative reconstruction (HIR, protocol B), and IMR (protocol C). We compared CT numbers, image noise, and contrast-to-noise ratio among 120-kVp protocol, protocol A, protocol B, and protocol C. In addition, we compared the noise reduction rate between HIR and IMR. Two independent readers compared image contrast, image noise, image sharpness, unfamiliar image texture, and overall image quality among the 4 protocols. The estimated effective dose (ED) of the 80-kVp protocol was 74% lower than that of the 120-kVp protocol (1.4 vs 5.4 mSv). The contrast-to-noise ratio of protocol C was significantly higher than that of protocol A. The noise reduction rate of IMR was significantly higher than that of HIR (P < 0.01). There was no significant difference in almost all qualitative image quality between 120-kVp protocol and protocol C except for image contrast. A 80-kVp protocol with IMR yields higher image quality with 74% decreased radiation dose and 40% decreased contrast agent dose as compared with a 120-kVp protocol, while decreasing more image noise compared with the 80-kVp protocol with HIR.

Value of 100 kVp scan with sinogram-affirmed iterative reconstruction algorithm on a single-source CT system during whole-body CT for radiation and contrast medium dose reduction: an intra-individual feasibility study.

PubMed

Nagayama, Y; Nakaura, T; Oda, S; Tsuji, A; Urata, J; Furusawa, M; Tanoue, S; Utsunomiya, D; Yamashita, Y

2018-02-01

To perform an intra-individual investigation of the usefulness of a contrast medium (CM) and radiation dose-reduction protocol using single-source computed tomography (CT) combined with 100 kVp and sinogram-affirmed iterative reconstruction (SAFIRE) for whole-body CT (WBCT; chest-abdomen-pelvis CT) in oncology patients. Forty-three oncology patients who had undergone WBCT under both 120 and 100 kVp protocols at different time points (mean interscan intervals: 98 days) were included retrospectively. The CM doses for the 120 and 100 kVp protocols were 600 and 480 mg iodine/kg, respectively; 120 kVp images were reconstructed with filtered back-projection (FBP), whereas 100 kVp images were reconstructed with FBP (100 kVp-F) and the SAFIRE (100 kVp-S). The size-specific dose estimate (SSDE), iodine load and image quality of each protocol were compared. The SSDE and iodine load of 100 kVp protocol were 34% and 21%, respectively, lower than of 120 kVp protocol (SSDE: 10.6±1.1 versus 16.1±1.8 mGy; iodine load: 24.8±4versus 31.5±5.5 g iodine, p<0.01). Contrast enhancement, objective image noise, contrast-to-noise-ratio, and visual score of 100 kVp-S were similar to or better than of 120 kVp protocol. Compared with the 120 kVp protocol, the combined use of 100 kVp and SAFIRE in WBCT for oncology assessment with an SSCT facilitated substantial reduction in the CM and radiation dose while maintaining image quality. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

CT and MR Protocol Standardization Across a Large Health System: Providing a Consistent Radiologist, Patient, and Referring Provider Experience.

PubMed

Sachs, Peter B; Hunt, Kelly; Mansoubi, Fabien; Borgstede, James

2017-02-01

Building and maintaining a comprehensive yet simple set of standardized protocols for a cross-sectional image can be a daunting task. A single department may have difficulty preventing "protocol creep," which almost inevitably occurs when an organized "playbook" of protocols does not exist and individual radiologists and technologists alter protocols at will and on a case-by-case basis. When multiple departments or groups function in a large health system, the lack of uniformity of protocols can increase exponentially. In 2012, the University of Colorado Hospital formed a large health system (UCHealth) and became a 5-hospital provider network. CT and MR imaging studies are conducted at multiple locations by different radiology groups. To facilitate consistency in ordering, acquisition, and appearance of a given study, regardless of location, we minimized the number of protocols across all scanners and sites of practice with a clinical indication-driven protocol selection and standardization process. Here we review the steps utilized to perform this process improvement task and insure its stability over time. Actions included creation of a standardized protocol template, which allowed for changes in electronic storage and management of protocols, designing a change request form, and formation of a governance structure. We utilized rapid improvement events (1 day for CT, 2 days for MR) and reduced 248 CT protocols into 97 standardized protocols and 168 MR protocols to 66. Additional steps are underway to further standardize output and reporting of imaging interpretation. This will result in an improved, consistent radiologist, patient, and provider experience across the system.

A fast screening protocol for carotid plaques imaging using 3D multi-contrast MRI without contrast agent.

PubMed

Zhang, Na; Zhang, Lei; Yang, Qi; Pei, Anqi; Tong, Xiaoxin; Chung, Yiu-Cho; Liu, Xin

2017-06-01

To implement a fast (~15min) MRI protocol for carotid plaque screening using 3D multi-contrast MRI sequences without contrast agent on a 3Tesla MRI scanner. 7 healthy volunteers and 25 patients with clinically confirmed transient ischemic attack or suspected cerebrovascular ischemia were included in this study. The proposed protocol, including 3D T1-weighted and T2-weighted SPACE (variable-flip-angle 3D turbo spin echo), and T1-weighted magnetization prepared rapid acquisition gradient echo (MPRAGE) was performed first and was followed by 2D T1-weighted and T2-weighted turbo spin echo, and post-contrast T1-weighted SPACE sequences. Image quality, number of plaques, and vessel wall thicknesses measured at the intersection of the plaques were evaluated and compared between sequences. Average examination time of the proposed protocol was 14.6min. The average image quality scores of 3D T1-weighted, T2-weighted SPACE, and T1-weighted magnetization prepared rapid acquisition gradient echo were 3.69, 3.75, and 3.48, respectively. There was no significant difference in detecting the number of plaques and vulnerable plaques using pre-contrast 3D images with or without post-contrast T1-weighted SPACE. The 3D SPACE and 2D turbo spin echo sequences had excellent agreement (R=0.96 for T1-weighted and 0.98 for T2-weighted, p<0.001) regarding vessel wall thickness measurements. The proposed protocol demonstrated the feasibility of attaining carotid plaque screening within a 15-minute scan, which provided sufficient anatomical coverage and critical diagnostic information. This protocol offers the potential for rapid and reliable screening for carotid plaques without contrast agent. Copyright © 2016. Published by Elsevier Inc.

Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience.

PubMed

Lv, Peijie; Liu, Jie; Chai, Yaru; Yan, Xiaopeng; Gao, Jianbo; Dong, Junqiang

2017-01-01

To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. One hundred and sixty patients were randomly divided into two scan protocols (n = 80 each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. • Automatic spectral imaging protocol selection provides appropriate scan protocols. • Abdominal CT is feasible using spectral imaging and 300 mgI/kg contrast agent. • 50-keV monochromatic images with 50 % ASIR provide optimal image quality.

A time and imaging cost analysis of low-risk ED observation patients: a conservative 64-section computed tomography coronary angiography "triple rule-out" compared to nuclear stress test strategy.

PubMed

Takakuwa, Kevin M; Halpern, Ethan J; Shofer, Frances S

2011-02-01

The study aimed to examine time and imaging costs of 2 different imaging strategies for low-risk emergency department (ED) observation patients with acute chest pain or symptoms suggestive of acute coronary syndrome. We compared a "triple rule-out" (TRO) 64-section multidetector computed tomography protocol with nuclear stress testing. This was a prospective observational cohort study of consecutive ED patients who were enrolled in our chest pain observation protocol during a 16-month period. Our standard observation protocol included a minimum of 2 sets of cardiac enzymes at least 6 hours apart followed by a nuclear stress test. Once a week, observation patients were offered a TRO (to evaluate for coronary artery disease, thoracic dissection, and pulmonary embolus) multidetector computed tomography with the option of further stress testing for those patients found to have evidence of coronary artery disease. We analyzed 832 consecutive observation patients including 214 patients who underwent the TRO protocol. Mean total length of stay was 16.1 hours for TRO patients, 16.3 hours for TRO plus other imaging test, 22.6 hours for nuclear stress testing, 23.3 hours for nuclear stress testing plus other imaging tests, and 23.7 hours for nuclear stress testing plus TRO (P < .0001 for TRO and TRO + other test compared to stress test ± other test). Mean imaging times were 3.6, 4.4, 5.9, 7.5, and 6.6 hours, respectively (P < .05 for TRO and TRO + other test compared to stress test ± other test). Mean imaging costs were $1307 for TRO patients vs $945 for nuclear stress testing. Triple rule-out reduced total length of stay and imaging time but incurred higher imaging costs. A per-hospital analysis would be needed to determine if patient time savings justify the higher imaging costs. Copyright © 2011 Elsevier Inc. All rights reserved.

The Effect of Participating in Suicide Research: Does Participating in a Research Protocol on Suicide and Psychiatric Symptoms Increase Suicide Ideation and Attempts?

ERIC Educational Resources Information Center

Smith, Phillip; Poindexter, Erin; Cukrowicz, Kelly

2010-01-01

The effect of engaging in an intensive research protocol that inquired extensively about psychiatric and suicide symptoms and exposed participants to a number of images, including suicide-related content was explored. Individuals experiencing a major depressive episode were called at 1 and 3 months after the initial protocol. Participants were…

A protocol for preparing, characterizing and using three RNA-specific, live cell imaging probes: E36, E144 and F22.

PubMed

Li, Qian; Chang, Young-Tae

2006-01-01

This protocol outlines a methodology for the preparation and characterization of three RNA-specific fluorescent probes (E36, E144 and F22) and their use in live cell imaging. It describes a detailed procedure for their chemical synthesis and purification; serial product characterization and quality control tests, including measurements of their fluorescence properties in solution, measurement of RNA specificity and analysis of cellular toxicity; and live cell staining and counterstaining with Hoechst or DAPI. Preparation and application of these RNA imaging probes takes 1 week.

Free-breathing imaging of the heart using 2D cine-GRICS (generalized reconstruction by inversion of coupled systems) with assessment of ventricular volumes and function.

PubMed

Vuissoz, Pierre-André; Odille, Freddy; Fernandez, Brice; Lohezic, Maelene; Benhadid, Adnane; Mandry, Damien; Felblinger, Jacques

2012-02-01

To assess cardiac function by means of a novel free-breathing cardiac magnetic resonance imaging (MRI) strategy. A stack of ungated 2D steady-state free precession (SSFP) slices was acquired during free breathing and reconstructed as cardiac cine imaging based on the generalized reconstruction by inversion of coupled systems (GRICS). A motion-compensated sliding window approach allows reconstructing cine movies with most motion artifacts cancelled. The proposed reconstruction uses prior knowledge from respiratory belts and electrocardiogram recordings and features a piecewise linear model that relates the electrocardiogram signal to cardiac displacements. The free-breathing protocol was validated in six subjects against a standard breath-held protocol. Image sharpness, as assessed by the image gradient entropy, was comparable to that of breath-held images and significantly better than in uncorrected images. Volumetric parameters of cardiac function in the left ventricle (LV) and right ventricle (RV) were similar, including end-systolic volumes, end-diastolic volumes and mass, stroke volumes, and ejection fractions (with differences of 3% ± 2.4 in the LV and 2.9% ± 4.4 in the RV). The duration of the free-breathing protocol was nearly the same as the breath-held protocol. Free-breathing cine-GRICS enables accurate assessment of volumetric parameters of cardiac function with efficient correction of motion. Copyright © 2011 Wiley Periodicals, Inc.

Experimental high-speed network

NASA Astrophysics Data System (ADS)

McNeill, Kevin M.; Klein, William P.; Vercillo, Richard; Alsafadi, Yasser H.; Parra, Miguel V.; Dallas, William J.

1993-09-01

Many existing local area networking protocols currently applied in medical imaging were originally designed for relatively low-speed, low-volume networking. These protocols utilize small packet sizes appropriate for text based communication. Local area networks of this type typically provide raw bandwidth under 125 MHz. These older network technologies are not optimized for the low delay, high data traffic environment of a totally digital radiology department. Some current implementations use point-to-point links when greater bandwidth is required. However, the use of point-to-point communications for a total digital radiology department network presents many disadvantages. This paper describes work on an experimental multi-access local area network called XFT. The work includes the protocol specification, and the design and implementation of network interface hardware and software. The protocol specifies the Physical and Data Link layers (OSI layers 1 & 2) for a fiber-optic based token ring providing a raw bandwidth of 500 MHz. The protocol design and implementation of the XFT interface hardware includes many features to optimize image transfer and provide flexibility for additional future enhancements which include: a modular hardware design supporting easy portability to a variety of host system buses, a versatile message buffer design providing 16 MB of memory, and the capability to extend the raw bandwidth of the network to 3.0 GHz.

Implementation of a Rapid, Protocol-based TIA Management Pathway.

PubMed

Jarhult, Susann J; Howell, Melissa L; Barnaure-Nachbar, Isabelle; Chang, Yuchiao; White, Benjamin A; Amatangelo, Mary; Brown, David F; Singhal, Aneesh B; Schwamm, Lee H; Silverman, Scott B; Goldstein, Joshua N

2018-03-01

Our goal was to assess whether use of a standardized clinical protocol improves efficiency for patients who present to the emergency department (ED) with symptoms of transient ischemic attack (TIA). We performed a structured, retrospective, cohort study at a large, urban, tertiary care academic center. In July 2012 this hospital implemented a standardized protocol for patients with suspected TIA. The protocol selected high-risk patients for admission and low/intermediate-risk patients to an ED observation unit for workup. Recommended workup included brain imaging, vascular imaging, cardiac monitoring, and observation. Patients were included if clinical providers determined the need for workup for TIA. We included consecutive patients presenting during a six-month period prior to protocol implementation, and those presenting between 6-12 months after implementation. Outcomes included ED length of stay (LOS), hospital LOS, use of neuroimaging, and 90-day risk of stroke or TIA. From 01/2012 to 06/2012, 130 patients were evaluated for TIA symptoms in the ED, and from 01/2013 to 06/2013, 150 patients. The final diagnosis was TIA or stroke in 45% before vs. 41% after (p=0.18). Following the intervention, the inpatient admission rate decreased from 62% to 24% (p<0.001), median ED LOS decreased by 1.2 hours (5.7 to 4.9 hours, p=0.027), and median total hospital LOS from 29.4 hours to 23.1 hours (p=0.019). The proportion of patients receiving head computed tomography (CT) went from 68% to 58% (p=0.087); brain magnetic resonance (MR) imaging from 83% to 88%, (p=0.44) neck CT angiography from 32% to 22% (p=0.039); and neck MR angiography from 61% to 72% (p=0.046). Ninety-day stroke or recurrent TIA among those with final diagnosis of TIA was 3% for both periods. Implementation of a TIA protocol significantly reduced ED LOS and total hospital LOS.

Preparation of Murine Submandibular Salivary Gland for Upright Intravital Microscopy.

PubMed

Ficht, Xenia; Thelen, Flavian; Stolp, Bettina; Stein, Jens V

2018-05-07

The submandibular salivary gland (SMG) is one of the three major salivary glands, and is of interest for many different fields of biological research, including cell biology, oncology, dentistry, and immunology. The SMG is an exocrine gland comprised of secretory epithelial cells, myofibroblasts, endothelial cells, nerves, and extracellular matrix. Dynamic cellular processes in the rat and mouse SMG have previously been imaged, mostly using inverted multi-photon microscope systems. Here, we describe a straightforward protocol for the surgical preparation and stabilization of the murine SMG in anesthetized mice for in vivo imaging with upright multi-photon microscope systems. We present representative intravital image sets of endogenous and adoptively transferred fluorescent cells, including the labeling of blood vessels or salivary ducts and second harmonic generation to visualize fibrillar collagen. In sum, our protocol allows for surgical preparation of mouse salivary glands in upright microscopy systems, which are commonly used for intravital imaging in the field of immunology.

Imaging Evaluation of Acute Traumatic Brain Injury

PubMed Central

Mutch, Christopher A.; Talbott, Jason F.; Gean, Alisa

2016-01-01

SYNOPSIS Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Imaging plays an important role in the evaluation, diagnosis, and triage of patients with TBI. Recent studies suggest that it will also help predict patient outcomes. TBI consists of multiple pathoanatomical entities. Here we review the current state of TBI imaging including its indications, benefits and limitations of the modalities, imaging protocols, and imaging findings for each these pathoanatomic entities. We also briefly survey advanced imaging techniques, which include a number of promising areas of TBI research. PMID:27637393

SU-F-J-16: Planar KV Imaging Dose Reduction Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gershkevitsh, E; Zolotuhhin, D

Purpose: IGRT has become an indispensable tool in modern radiotherapy with kV imaging used in many departments due to superior image quality and lower dose when compared to MV imaging. Many departments use manufacturer supplied protocols for imaging which are not always optimised between image quality and radiation dose (ALARA). Methods: Whole body phantom PBU-50 (Kyoto Kagaku ltd., Japan) for imaging in radiology has been imaged on Varian iX accelerator (Varian Medical Systems, USA) with OBI 1.5 system. Manufacturer’s default protocols were adapted by modifying kV and mAs values when imaging different anatomical regions of the phantom (head, thorax, abdomen,more » pelvis, extremities). Images with different settings were independently reviewed by two persons and their suitability for IGRT set-up correction protocols were evaluated. The suitable images with the lowest mAs were then selected. The entrance surface dose (ESD) for manufacturer’s default protocols and modified protocols were measured with RTI Black Piranha (RTI Group, Sweden) and compared. Image quality was also measured with kVQC phantom (Standard Imaging, USA) for different protocols. The modified protocols have been applied for clinical work. Results: For most cases optimized protocols reduced the ESD on average by a factor of 3(range 0.9–8.5). Further reduction in ESD has been observed by applying bow-tie filter designed for CBCT. The largest reduction in dose (12.2 times) was observed for Thorax lateral protocol. The dose was slightly increased (by 10%) for large pelvis AP protocol. Conclusion: Manufacturer’s default IGRT protocols could be optimised to reduce the ESD to the patient without losing the necessary image quality for patient set-up correction. For patient set-up with planar kV imaging the bony anatomy is mostly used and optimization should focus on this aspect. Therefore, the current approach with anthropomorphic phantom is more advantageous in optimization over standard kV quality control phantoms and SNR metrics.« less

Dose, image quality and spine modeling assessment of biplanar EOS micro-dose radiographs for the follow-up of in-brace adolescent idiopathic scoliosis patients.

PubMed

Morel, Baptiste; Moueddeb, Sonia; Blondiaux, Eleonore; Richard, Stephen; Bachy, Manon; Vialle, Raphael; Ducou Le Pointe, Hubert

2018-05-01

The aim of this study was to compare the radiation dose, image quality and 3D spine parameter measurements of EOS low-dose and micro-dose protocols for in-brace adolescent idiopathic scoliosis (AIS) patients. We prospectively included 25 consecutive patients (20 females, 5 males) followed for AIS and undergoing brace treatment. The mean age was 12 years (SD 2 years, range 8-15 years). For each patient, in-brace biplanar EOS radiographs were acquired in a standing position using both the conventional low-dose and micro-dose protocols. Dose area product (DAP) was systematically recorded. Diagnostic image quality was qualitatively assessed by two radiologists for visibility of anatomical structures. The reliability of 3D spine modeling between two operators was quantitatively evaluated for the most clinically relevant 3D radiological parameters using intraclass correlation coefficient (ICC). The mean DAP for the posteroanterior and lateral acquisitions was 300 ± 134 and 433 ± 181 mGy cm 2 for the low-dose radiographs, and 41 ± 19 and 81 ± 39 mGy cm 2 for micro-dose radiographs. Image quality was lower with the micro-dose protocol. The agreement was "good" to "very good" for all measured clinical parameters when comparing the low-dose and micro-dose protocols (ICC > 0.73). The micro-dose protocol substantially reduced the delivered dose (by a factor of 5-7 compared to the low-dose protocol) in braced children with AIS. Although image quality was reduced, the micro-dose protocol proved to be adapted to radiological follow-up, with adequate image quality and reliable clinical measurements. These slides can be retrieved under Electronic Supplementary Material.

Live-cell confocal microscopy and quantitative 4D image analysis of anchor cell invasion through the basement membrane in C. elegans

PubMed Central

Kelley, Laura C.; Wang, Zheng; Hagedorn, Elliott J.; Wang, Lin; Shen, Wanqing; Lei, Shijun; Johnson, Sam A.; Sherwood, David R.

2018-01-01

Cell invasion through basement membrane (BM) barriers is crucial during development, leukocyte trafficking, and for the spread of cancer. Despite its importance in normal and diseased states, the mechanisms that direct invasion are poorly understood, in large part because of the inability to visualize dynamic cell-basement membrane interactions in vivo. This protocol describes multi-channel time-lapse confocal imaging of anchor cell invasion in live C. elegans. Methods presented include outline slide preparation and worm growth synchronization (15 min), mounting (20 min), image acquisition (20-180 min), image processing (20 min), and quantitative analysis (variable timing). Images acquired enable direct measurement of invasive dynamics including invadopodia formation, cell membrane protrusions, and BM removal. This protocol can be combined with genetic analysis, molecular activity probes, and optogenetic approaches to uncover molecular mechanisms underlying cell invasion. These methods can also be readily adapted for real-time analysis of cell migration, basement membrane turnover, and cell membrane dynamics by any worm laboratory. PMID:28880279

Biparametric 3T Magnetic Resonance Imaging for prostatic cancer detection in a biopsy-naïve patient population: a further improvement of PI-RADS v2?

PubMed

Stanzione, Arnaldo; Imbriaco, Massimo; Cocozza, Sirio; Fusco, Ferdinando; Rusconi, Giovanni; Nappi, Carmela; Mirone, Vincenzo; Mangiapia, Francesco; Brunetti, Arturo; Ragozzino, Alfonso; Longo, Nicola

2016-12-01

To prospectively determine the diagnostic accuracy of a biparametric 3T magnetic resonance imaging protocol (BP-MRI) for prostatic cancer detection, compared to a multiparametric MRI protocol (MP-MRI), in a biopsy naïve patient population. Eighty-two untreated patients (mean age 65±7.6years) with clinical suspicion of prostate cancer and/or altered prostate-specific antigen (PSA) levels underwent a MP-MRI, including T2-weighted imaging, diffusion-weighted imaging (with the correspondent apparent diffusion coefficient maps) and dynamic contrast enhanced sequence, followed by prostate biopsy. Two radiologists reviewed both the BP-MRI and the MP-MRI protocols to establish a radiological diagnosis. Receiver operating characteristics curves were obtained to determine the diagnostic performance of the two protocols. The mean PSA level was 8.8±8.1ng/ml. A total of 34 prostatic tumors were identified, with a Gleason score that ranged from 3+3 to 5+4. Of these 34 tumors, 29 were located within the peripheral zone and 5 in the transitional zone. BP-MRI and MP-MRI showed a similar performance in terms of overall diagnostic accuracy, with an area under the curve of 0.91 and 0.93, respectively (p=n.s.). BP-MRI prostate protocol is feasible for prostatic cancer detection compared to a standard MP-MRI protocol, requiring a shorter acquisition and interpretation time, with comparable diagnostic accuracy to the conventional protocol, without the administration of gadolinium-based contrast agent. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dual-energy CT and ceramic or titanium prostheses material reduce CT artifacts and provide superior image quality of total knee arthroplasty.

PubMed

Kasparek, Maximilian F; Töpker, Michael; Lazar, Mathias; Weber, Michael; Kasparek, Michael; Mang, Thomas; Apfaltrer, Paul; Kubista, Bernd; Windhager, Reinhard; Ringl, Helmut

2018-06-07

To evaluate the influence of different scan parameters for single-energy CT and dual-energy CT, as well as the impact of different material used in a TKA prosthesis on image quality and the extent of metal artifacts. Eight pairs of TKA prostheses from different vendors were examined in a phantom set-up. Each pair consisted of a conventional CoCr prosthesis and the corresponding anti-allergic prosthesis (full titanium, ceramic, or ceramic-coated) from the same vendor. Nine different (seven dual-energy CT and two single-energy CT) scan protocols with different characteristics were used to determine the most suitable CT protocol for TKA imaging. Quantitative image analysis included assessment of blooming artifacts (metal implants appear thicker on CT than they are, given as virtual growth in mm in this paper) and streak artifacts (thick dark lines around metal). Qualitative image analysis was used to investigate the bone-prosthesis interface. The full titanium prosthesis and full ceramic knee showed significantly fewer blooming artifacts compared to the standard CoCr prosthesis (mean virtual growth 0.6-2.2 mm compared to 2.9-4.6 mm, p < 0.001). Dual-energy CT protocols showed less blooming (range 3.3-3.8 mm) compared to single-energy protocols (4.6-5.5 mm). The full titanium and full ceramic prostheses showed significantly fewer streak artifacts (mean standard deviation 77-86 Hounsfield unit (HU)) compared to the standard CoCr prosthesis (277-334 HU, p < 0.001). All dual-energy CT protocols had fewer metal streak artifacts (215-296 HU compared to single-energy CT protocols (392-497 HU)). Full titanium and ceramic prostheses were ranked superior with regard to the image quality at the bone/prosthesis interface compared to a standard CoCr prosthesis, and all dual-energy CT protocols were ranked better than single-energy protocols. Dual-energy CT and ceramic or titanium prostheses reduce CT artifacts and provide superior image quality of total knee arthroplasty at the bone/prosthesis interface. These findings support the use of dual-energy CT as a solid imaging base for clinical decision-making and the use of full-titanium or ceramic prostheses to allow for better CT visualization of the bone-prosthesis interface.

Ultrasound Imaging of Spine: State of the Art and Utility for Space Flight

NASA Technical Reports Server (NTRS)

Sargsyan, Ashot E.; Bouffard, Antonio J.; Garcia, Kathleen; Hamilton, Douglas R.; Van Holsbeeck, Marnix; Ebert, Douglas J. W.; Dulchavsky, Scott A.

2010-01-01

Introduction: Ultrasound imaging (sonography) has been increasingly used for both primary diagnosis and monitoring of musculoskeletal injury, including fractures. In certain injuries, sonography has been shown to equal or surpass Magnetic Resonance Imaging in accuracy. Long-term exposure to reduced gravity may be expected to cause physiological and anatomical changes of the musculoskeletal system, which are not fully described or understood. In a limited-resource environment like space flight, sonography will likely remain the only imaging modality; therefore, further attention to its potential is warranted, including its ability to image anatomical deviations as well as irregularities of vertebrae and the spinal column. Methods: A thorough review of literature was conducted on the subject. A multipurpose ultrasound system was used to identify specific vertebrae, intervertebral disks, and other structures of the cervical spine in healthy volunteers, selected to represent various age, gender, and Body Mass Index (BMI) groups. Sonographic views were sought that would parallel radiographic views and signs used in the diagnosis of cervical spine injuries. Results: While using widely accepted radiographic signs of cervical spine injury, this sonographic protocol development effort resulted in successful identification of scanning planes and imaging protocols that could serve as alternatives for radiography. Some of these views are also applicable to diagnosing degenerative disk and bone disease, and other non-traumatic spine pathology. Strong, preliminary correlation has been demonstrated in a number of clinical cases between sonography and other imaging modalities. Conclusion: In the absence of radiography, sonography can be used to diagnose or rule out certain common types of cervical spine conditions including injury. Clinical validation of the findings appears to be realistic and would facilitate establishment of new sonographic protocols for special environments with lacking radiographic capability, such as human space flight.

Normalization of cortical thickness measurements across different T1 magnetic resonance imaging protocols by novel W-Score standardization.

PubMed

Chung, Jinyong; Yoo, Kwangsun; Lee, Peter; Kim, Chan Mi; Roh, Jee Hoon; Park, Ji Eun; Kim, Sang Joon; Seo, Sang Won; Shin, Jeong-Hyeon; Seong, Joon-Kyung; Jeong, Yong

2017-10-01

The use of different 3D T1-weighted magnetic resonance (T1 MR) imaging protocols induces image incompatibility across multicenter studies, negating the many advantages of multicenter studies. A few methods have been developed to address this problem, but significant image incompatibility still remains. Thus, we developed a novel and convenient method to improve image compatibility. W-score standardization creates quality reference values by using a healthy group to obtain normalized disease values. We developed a protocol-specific w-score standardization to control the protocol effect, which is applied to each protocol separately. We used three data sets. In dataset 1, brain T1 MR images of normal controls (NC) and patients with Alzheimer's disease (AD) from two centers, acquired with different T1 MR protocols, were used (Protocol 1 and 2, n = 45/group). In dataset 2, data from six subjects, who underwent MRI with two different protocols (Protocol 1 and 2), were used with different repetition times, echo times, and slice thicknesses. In dataset 3, T1 MR images from a large number of healthy normal controls (Protocol 1: n = 148, Protocol 2: n = 343) were collected for w-score standardization. The protocol effect and disease effect on subjects' cortical thickness were analyzed before and after the application of protocol-specific w-score standardization. As expected, different protocols resulted in differing cortical thickness measurements in both NC and AD subjects. Different measurements were obtained for the same subject when imaged with different protocols. Multivariate pattern difference between measurements was observed between the protocols. Classification accuracy between two protocols was nearly 90%. After applying protocol-specific w-score standardization, the differences between the protocols substantially decreased. Most importantly, protocol-specific w-score standardization reduced both univariate and multivariate differences in the images while maintaining the AD disease effect. Compared to conventional regression methods, our method showed the best performance for in terms of controlling the protocol effect while preserving disease information. Protocol-specific w-score standardization effectively resolved the concerns of conventional regression methods. It showed the best performance for improving the compatibility of a T1 MR post-processed feature, cortical thickness. Copyright © 2017 Elsevier Inc. All rights reserved.

SU-G-IeP2-10: Lens Dose Reduction by Patient Position Modification During Neck CT Exams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mosher, E; Lee, C; Butman, J

Purpose: Irradiation of the lens during a neck CT may increase a patient’s risk of developing cataracts later in life. Radiologists and technologists at the National Institutes of Health Clinical Center (NIHCC) have developed new CT imaging protocols that include a reduction in scan range and modifying neck positioning using a head tilt. This study will evaluate the efficacy of this protocol in the reduction of lens dose. Methods: We retrieved CT images of five male patients who had two sets of CT images: before and after the implementation of the new protocol. The lens doses before the new protocolmore » were calculated using an in-house CT dose calculator, National Cancer Institute dosimetry system for CT (NCICT), where computational human phantoms with no head tilt are included. We also calculated the lens dose for the patient CT conducted after the new protocol by using an adult male computational phantom with the neck position deformed to match the angle of the head tilt. We also calculated the doses to other radiosensitive organs including the globes of the eye, brain, pituitary gland and salivary glands before and after head tilt. Results: Our dose calculations demonstrated that modifying neck position reduced dose to the lens by 89% on average (range: 86–96%). Globe, brain, pituitary and salivary gland doses also decreased by an average of 65% (51–95%), 38% (−8–66%), 34% (−43–84%) and 14% (13–14%), respectively. The new protocol resulted in a nearly ten-fold decrease in lens dose. Conclusion: The use of a head tilt and scan range reduction is an easy and effective method to reduce radiation exposure to the lens and other radiosensitive organs, while still allowing for the inclusion of critical neck structures in the CT image. We are expanding our study to a total of 10 males and 10 females.« less

Contrast medium administration and image acquisition parameters in renal CT angiography: what radiologists need to know.

PubMed

Saade, Charbel; Deeb, Ibrahim Alsheikh; Mohamad, Maha; Al-Mohiy, Hussain; El-Merhi, Fadi

2016-01-01

Over the last decade, exponential advances in computed tomography (CT) technology have resulted in improved spatial and temporal resolution. Faster image acquisition enabled renal CT angiography to become a viable and effective noninvasive alternative in diagnosing renal vascular pathologies. However, with these advances, new challenges in contrast media administration have emerged. Poor synchronization between scanner and contrast media administration have reduced the consistency in image quality with poor spatial and contrast resolution. Comprehensive understanding of contrast media dynamics is essential in the design and implementation of contrast administration and image acquisition protocols. This review includes an overview of the parameters affecting renal artery opacification and current protocol strategies to achieve optimal image quality during renal CT angiography with iodinated contrast media, with current safety issues highlighted.

Rapid Waterborne Pathogen Detection with Mobile Electronics.

PubMed

Wu, Tsung-Feng; Chen, Yu-Chen; Wang, Wei-Chung; Kucknoor, Ashwini S; Lin, Che-Jen; Lo, Yu-Hwa; Yao, Chun-Wei; Lian, Ian

2017-06-09

Pathogen detection in water samples, without complex and time consuming procedures such as fluorescent-labeling or culture-based incubation, is essential to public safety. We propose an immunoagglutination-based protocol together with the microfluidic device to quantify pathogen levels directly from water samples. Utilizing ubiquitous complementary metal-oxide-semiconductor (CMOS) imagers from mobile electronics, a low-cost and one-step reaction detection protocol is developed to enable field detection for waterborne pathogens. 10 mL of pathogen-containing water samples was processed using the developed protocol including filtration enrichment, immune-reaction detection and imaging processing. The limit of detection of 10 E. coli O157:H7 cells/10 mL has been demonstrated within 10 min of turnaround time. The protocol can readily be integrated into a mobile electronics such as smartphones for rapid and reproducible field detection of waterborne pathogens.

Genetic Interaction Score (S-Score) Calculation, Clustering, and Visualization of Genetic Interaction Profiles for Yeast.

PubMed

Roguev, Assen; Ryan, Colm J; Xu, Jiewei; Colson, Isabelle; Hartsuiker, Edgar; Krogan, Nevan

2018-02-01

This protocol describes computational analysis of genetic interaction screens, ranging from data capture (plate imaging) to downstream analyses. Plate imaging approaches using both digital camera and office flatbed scanners are included, along with a protocol for the extraction of colony size measurements from the resulting images. A commonly used genetic interaction scoring method, calculation of the S-score, is discussed. These methods require minimal computer skills, but some familiarity with MATLAB and Linux/Unix is a plus. Finally, an outline for using clustering and visualization software for analysis of resulting data sets is provided. © 2018 Cold Spring Harbor Laboratory Press.

Web tools for large-scale 3D biological images and atlases

PubMed Central

2012-01-01

Background Large-scale volumetric biomedical image data of three or more dimensions are a significant challenge for distributed browsing and visualisation. Many images now exceed 10GB which for most users is too large to handle in terms of computer RAM and network bandwidth. This is aggravated when users need to access tens or hundreds of such images from an archive. Here we solve the problem for 2D section views through archive data delivering compressed tiled images enabling users to browse through very-large volume data in the context of a standard web-browser. The system provides an interactive visualisation for grey-level and colour 3D images including multiple image layers and spatial-data overlay. Results The standard Internet Imaging Protocol (IIP) has been extended to enable arbitrary 2D sectioning of 3D data as well a multi-layered images and indexed overlays. The extended protocol is termed IIP3D and we have implemented a matching server to deliver the protocol and a series of Ajax/Javascript client codes that will run in an Internet browser. We have tested the server software on a low-cost linux-based server for image volumes up to 135GB and 64 simultaneous users. The section views are delivered with response times independent of scale and orientation. The exemplar client provided multi-layer image views with user-controlled colour-filtering and overlays. Conclusions Interactive browsing of arbitrary sections through large biomedical-image volumes is made possible by use of an extended internet protocol and efficient server-based image tiling. The tools open the possibility of enabling fast access to large image archives without the requirement of whole image download and client computers with very large memory configurations. The system was demonstrated using a range of medical and biomedical image data extending up to 135GB for a single image volume. PMID:22676296

Effect of slice thickness on image noise and diagnostic content of single-source-dual energy computed tomography

NASA Astrophysics Data System (ADS)

Alshipli, Marwan; Kabir, Norlaili A.

2017-05-01

Computed tomography (CT) employs X-ray radiation to create cross-sectional images. Dual-energy CT acquisition includes the images acquired from an alternating voltage of X-ray tube: a low- and a high-peak kilovoltage. The main objective of this study is to determine the best slice thickness that reduces image noise with adequate diagnostic information using dual energy CT head protocol. The study used the ImageJ software and statistical analyses to aid the medical image analysis of dual-energy CT. In this study, ImageJ software and F-test were utilised as the combination methods to analyse DICOM CT images. They were used to investigate the effect of slice thickness on noise and visibility in dual-energy CT head protocol images. Catphan-600 phantom was scanned at different slice thickness values;.6, 1, 2, 3, 4, 5 and 6 mm, then quantitative analyses were carried out. The DECT operated in helical mode with another fixed scan parameter values. Based on F-test statistical analyses, image noise at 0.6, 1, and 2 mm were significantly different compared to the other images acquired at slice thickness of 3, 4, 5, and 6 mm. However, no significant differences of image noise were observed at 3, 4, 5, and 6 mm. As a result, better diagnostic image value, image visibility, and lower image noise in dual-energy CT head protocol was observed at a slice thickness of 3 mm.

Mobile C-arm cone-beam CT for guidance of spine surgery: Image quality, radiation dose, and integration with interventional guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schafer, S.; Nithiananthan, S.; Mirota, D. J.

Purpose: A flat-panel detector based mobile isocentric C-arm for cone-beam CT (CBCT) has been developed to allow intraoperative 3D imaging with sub-millimeter spatial resolution and soft-tissue visibility. Image quality and radiation dose were evaluated in spinal surgery, commonly relying on lower-performance image intensifier based mobile C-arms. Scan protocols were developed for task-specific imaging at minimum dose, in-room exposure was evaluated, and integration of the imaging system with a surgical guidance system was demonstrated in preclinical studies of minimally invasive spine surgery. Methods: Radiation dose was assessed as a function of kilovolt (peak) (80-120 kVp) and milliampere second using thoracic andmore » lumbar spine dosimetry phantoms. In-room radiation exposure was measured throughout the operating room for various CBCT scan protocols. Image quality was assessed using tissue-equivalent inserts in chest and abdomen phantoms to evaluate bone and soft-tissue contrast-to-noise ratio as a function of dose, and task-specific protocols (i.e., visualization of bone or soft-tissues) were defined. Results were applied in preclinical studies using a cadaveric torso simulating minimally invasive, transpedicular surgery. Results: Task-specific CBCT protocols identified include: thoracic bone visualization (100 kVp; 60 mAs; 1.8 mGy); lumbar bone visualization (100 kVp; 130 mAs; 3.2 mGy); thoracic soft-tissue visualization (100 kVp; 230 mAs; 4.3 mGy); and lumbar soft-tissue visualization (120 kVp; 460 mAs; 10.6 mGy) - each at (0.3 x 0.3 x 0.9 mm{sup 3}) voxel size. Alternative lower-dose, lower-resolution soft-tissue visualization protocols were identified (100 kVp; 230 mAs; 5.1 mGy) for the lumbar region at (0.3 x 0.3 x 1.5 mm{sup 3}) voxel size. Half-scan orbit of the C-arm (x-ray tube traversing under the table) was dosimetrically advantageous (prepatient attenuation) with a nonuniform dose distribution ({approx}2 x higher at the entrance side than at isocenter, and {approx}3-4 lower at the exit side). The in-room dose (microsievert) per unit scan dose (milligray) ranged from {approx}21 {mu}Sv/mGy on average at tableside to {approx}0.1 {mu}Sv/mGy at 2.0 m distance to isocenter. All protocols involve surgical staff stepping behind a shield wall for each CBCT scan, therefore imparting {approx}zero dose to staff. Protocol implementation in preclinical cadaveric studies demonstrate integration of the C-arm with a navigation system for spine surgery guidance-specifically, minimally invasive vertebroplasty in which the system provided accurate guidance and visualization of needle placement and bone cement distribution. Cumulative dose including multiple intraoperative scans was {approx}11.5 mGy for CBCT-guided thoracic vertebroplasty and {approx}23.2 mGy for lumbar vertebroplasty, with dose to staff at tableside reduced to {approx}1 min of fluoroscopy time ({approx}40-60 {mu}Sv), compared to 5-11 min for the conventional approach. Conclusions: Intraoperative CBCT using a high-performance mobile C-arm prototype demonstrates image quality suitable to guidance of spine surgery, with task-specific protocols providing an important basis for minimizing radiation dose, while maintaining image quality sufficient for surgical guidance. Images demonstrate a significant advance in spatial resolution and soft-tissue visibility, and CBCT guidance offers the potential to reduce fluoroscopy reliance, reducing cumulative dose to patient and staff. Integration with a surgical guidance system demonstrates precise tracking and visualization in up-to-date images (alleviating reliance on preoperative images only), including detection of errors or suboptimal surgical outcomes in the operating room.« less

Accessing Multi-Dimensional Images and Data Cubes in the Virtual Observatory

NASA Astrophysics Data System (ADS)

Tody, Douglas; Plante, R. L.; Berriman, G. B.; Cresitello-Dittmar, M.; Good, J.; Graham, M.; Greene, G.; Hanisch, R. J.; Jenness, T.; Lazio, J.; Norris, P.; Pevunova, O.; Rots, A. H.

2014-01-01

Telescopes across the spectrum are routinely producing multi-dimensional images and datasets, such as Doppler velocity cubes, polarization datasets, and time-resolved “movies.” Examples of current telescopes producing such multi-dimensional images include the JVLA, ALMA, and the IFU instruments on large optical and near-infrared wavelength telescopes. In the near future, both the LSST and JWST will also produce such multi-dimensional images routinely. High-energy instruments such as Chandra produce event datasets that are also a form of multi-dimensional data, in effect being a very sparse multi-dimensional image. Ensuring that the data sets produced by these telescopes can be both discovered and accessed by the community is essential and is part of the mission of the Virtual Observatory (VO). The Virtual Astronomical Observatory (VAO, http://www.usvao.org/), in conjunction with its international partners in the International Virtual Observatory Alliance (IVOA), has developed a protocol and an initial demonstration service designed for the publication, discovery, and access of arbitrarily large multi-dimensional images. The protocol describing multi-dimensional images is the Simple Image Access Protocol, version 2, which provides the minimal set of metadata required to characterize a multi-dimensional image for its discovery and access. A companion Image Data Model formally defines the semantics and structure of multi-dimensional images independently of how they are serialized, while providing capabilities such as support for sparse data that are essential to deal effectively with large cubes. A prototype data access service has been deployed and tested, using a suite of multi-dimensional images from a variety of telescopes. The prototype has demonstrated the capability to discover and remotely access multi-dimensional data via standard VO protocols. The prototype informs the specification of a protocol that will be submitted to the IVOA for approval, with an operational data cube service to be delivered in mid-2014. An associated user-installable VO data service framework will provide the capabilities required to publish VO-compatible multi-dimensional images or data cubes.

Rapid Diagnosis of Tuberculosis by Real-Time High-Resolution Imaging of Mycobacterium tuberculosis Colonies.

PubMed

Ghodbane, Ramzi; Asmar, Shady; Betzner, Marlena; Linet, Marie; Pierquin, Joseph; Raoult, Didier; Drancourt, Michel

2015-08-01

Culture remains the cornerstone of diagnosis for pulmonary tuberculosis, but the fastidiousness of Mycobacterium tuberculosis may delay culture-based diagnosis for weeks. We evaluated the performance of real-time high-resolution imaging for the rapid detection of M. tuberculosis colonies growing on a solid medium. A total of 50 clinical specimens, including 42 sputum specimens, 4 stool specimens, 2 bronchoalveolar lavage fluid specimens, and 2 bronchial aspirate fluid specimens were prospectively inoculated into (i) a commercially available Middlebrook broth and evaluated for mycobacterial growth indirectly detected by measuring oxygen consumption (standard protocol) and (ii) a home-made solid medium incubated in an incubator featuring real-time high-resolution imaging of colonies (real-time protocol). Isolates were identified by Ziehl-Neelsen staining and matrix-assisted laser desorption ionization-time of flight mass spectrometry. Use of the standard protocol yielded 14/50 (28%) M. tuberculosis isolates, which is not significantly different from the 13/50 (26%) M. tuberculosis isolates found using the real-time protocol (P = 1.00 by Fisher's exact test), and the contamination rate of 1/50 (2%) was not significantly different from the contamination rate of 2/50 (4%) using the real-time protocol (P = 1.00). The real-time imaging protocol showed a 4.4-fold reduction in time to detection, 82 ± 54 h versus 360 ± 142 h (P < 0.05). These preliminary data give the proof of concept that real-time high-resolution imaging of M. tuberculosis colonies is a new technology that shortens the time to growth detection and the laboratory diagnosis of pulmonary tuberculosis. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Diagnostic performance of a streamlined 18F-choline PET-CT protocol for the detection of prostate carcinoma recurrence in combination with appropriate-use criteria.

PubMed

Frood, R; Baren, J; McDermott, G; Bottomley, D; Patel, C; Scarsbrook, A

2018-04-30

To evaluate the efficacy of single time-point half-body (skull base to thighs) fluorine-18 choline positron emission tomography-computed tomography (PET-CT) compared to a triple-phase acquisition protocol in the detection of prostate carcinoma recurrence. Consecutive choline PET-CT studies performed at a single tertiary referral centre in patients with biochemical recurrence of prostate carcinoma between September 2012 and March 2017 were reviewed retrospectively. The indication for the study, imaging protocol used, imaging findings, whether management was influenced by the PET-CT, and subsequent patient outcome were recorded. Ninety-one examinations were performed during the study period; 42 were carried out using a triple-phase protocol (dynamic pelvic imaging for 20 minutes after tracer injection, half-body acquisition at 60 minutes and delayed pelvic scan at 90 minutes) between 2012 and August 2015. Subsequently following interim review of diagnostic performance, a streamlined protocol and appropriate-use criteria were introduced. Forty-nine examinations were carried out using the single-phase protocol between 2015 and 2017. Twenty-nine (69%) of the triple-phase studies were positive for recurrence compared to 38 (78%) of the single-phase studies. Only one patient who had a single-phase study would have benefited from a dynamic acquisition, they have required no further treatment or imaging and are currently under prostate-specific antigen (PSA) surveillance. Choline PET-CT remains a useful tool for the detection of prostate recurrence when used in combination with appropriate-use criteria. Removal of dynamic and delayed acquisition phases reduces study time without adversely affecting accuracy. Benefits include shorter imaging time which improves patient comfort, reduced cost, and improved scanner efficiency. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Anomalous Aortic Origin of Coronary Arteries in the Young: Echocardiographic Evaluation With Surgical Correlation.

PubMed

Lorber, Richard; Srivastava, Shubhika; Wilder, Travis J; McIntyre, Susan; DeCampli, William M; Williams, William G; Frommelt, Peter C; Parness, Ira A; Blackstone, Eugene H; Jacobs, Marshall L; Mertens, Luc; Brothers, Julie A; Herlong, J René

2015-11-01

This study sought to compare findings from institutional echocardiographic reports with imaging core laboratory (ICL) review of corresponding echocardiographic images and operative reports in 159 patients with anomalous aortic origin of a coronary artery (AAOCA). The study also sought to develop a "best practice" protocol for imaging and interpreting images in establishing the diagnosis of AAOCA. AAOCA is associated with sudden death in the young. Underlying anatomic risk factors that can cause ischemia-related events include coronary arterial ostial stenosis, intramural course of the proximal coronary within the aortic wall, interarterial course, and potential compression between the great arteries. Consistent protocols for diagnosing and evaluating these features are lacking, potentially precluding the ability to risk stratify patients based on evidence and plan surgical strategy. For a prescribed set of anatomic AAOCA features, percentages of missing data in institutional echocardiographic reports were calculated. For each feature, agreement among institutional echocardiographic reports, ICL review of images, and surgical reports was evaluated using the weighted kappa statistic. An echocardiographic imaging protocol was developed heuristically to reduce differences between institutional reports and ICL review. A total of 13%, 33%, and 62% of echocardiograms were missing images enabling diagnosis of intra-arterial course, proximal intramural course, and high ostial takeoff, respectively. There was poor agreement between institutional reports and ICL review for diagnosis of origin of coronary artery, interarterial course, intramural course, and acute angle takeoff (kappa = 0.74, 0.11, -0.03, 0.13, respectively). Surgical findings were also significantly different from those of reports, and to a lesser extent ICL reviews. The resulting protocol contains technical recommendations for imaging each of these features. Poor agreement between institutional reports and ICL review for AAOCA suggests need for an imaging protocol to permit evidence-based risk stratification and surgical planning. Even then, delineation of echocardiographic details in AAOCA will remain imperfect. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Fast and Noninvasive Characterization of Suspicious Lesions Detected at Breast Cancer X-Ray Screening: Capability of Diffusion-weighted MR Imaging with MIPs.

PubMed

Bickelhaupt, Sebastian; Laun, Frederik B; Tesdorff, Jana; Lederer, Wolfgang; Daniel, Heidi; Stieber, Anne; Delorme, Stefan; Schlemmer, Heinz-Peter

2016-03-01

To evaluate the ability of a diagnostic abbreviated magnetic resonance (MR) imaging protocol consisting of maximum intensity projections (MIPs) from diffusion-weighted imaging with background suppression (DWIBS) and unenhanced morphologic sequences to help predict the likelihood of malignancy on suspicious screening x-ray mammograms, as compared with an abbreviated contrast material-enhanced MR imaging protocol and a full diagnostic breast MR imaging protocol. This prospective institutional review board-approved study included 50 women (mean age, 57.1 years; range, 50-69 years), who gave informed consent and who had suspicious screening mammograms and an indication for biopsy, from September 2014 to January 2015. Before biopsy, full diagnostic contrast-enhanced MR imaging was performed that included DWIBS (b = 1500 sec/mm(2)). Two abbreviated protocols (APs) based on MIPs were evaluated regarding the potential to exclude malignancy: DWIBS (AP1) and subtraction images from the first postcontrast and the unenhanced series (AP2). Diagnostic indexes of both methods were examined by using the McNemar test and were compared with those of the full diagnostic protocol and histopathologic findings. Twenty-four of 50 participants had a breast carcinoma. With AP1 (DWIBS), the sensitivity was 0.92 (95% confidence interval [CI]: 0.73, 0.98), the specificity was 0.94 (95% CI: 0.77, 0.99), the negative predictive value (NPV) was 0.92 (95% CI: 0.75, 0.99), and the positive predictive value (PPV) was 0.93 (95% CI: 0.75, 0.99). The mean reading time was 29.7 seconds (range, 4.9-110.0 seconds) and was less than 3 seconds (range, 1.2-7.6 seconds) in the absence of suspicious findings on the DWIBS MIPs. With the AP2 protocol, the sensitivity was 0.85 (95% CI: 0.78, 0.95), the specificity was 0.90 (95% CI: 0.72, 0.97), the NPV was 0.87 (95% CI: 0.69, 0.95), the PPV was 0.89 (95% CI: 0.69, 0.97), and the mean reading time was 29.6 seconds (range, 6.0-100.0 seconds). Unenhanced diagnostic MR imaging (DWIBS mammography), with an NPV of 0.92 and an acquisition time of less than 7 minutes, could help exclude malignancy in women with suspicious x-ray screening mammograms. The method has the potential to reduce unnecessary invasive procedures and emotional distress for breast cancer screening participants if it is used as a complement after the regular screening clarification procedure.

A comprehensive study on the relationship between the image quality and imaging dose in low-dose cone beam CT

NASA Astrophysics Data System (ADS)

Yan, Hao; Cervino, Laura; Jia, Xun; Jiang, Steve B.

2012-04-01

While compressed sensing (CS)-based algorithms have been developed for the low-dose cone beam CT (CBCT) reconstruction, a clear understanding of the relationship between the image quality and imaging dose at low-dose levels is needed. In this paper, we qualitatively investigate this subject in a comprehensive manner with extensive experimental and simulation studies. The basic idea is to plot both the image quality and imaging dose together as functions of the number of projections and mAs per projection over the whole clinically relevant range. On this basis, a clear understanding of the tradeoff between the image quality and imaging dose can be achieved and optimal low-dose CBCT scan protocols can be developed to maximize the dose reduction while minimizing the image quality loss for various imaging tasks in image-guided radiation therapy (IGRT). Main findings of this work include (1) under the CS-based reconstruction framework, image quality has little degradation over a large range of dose variation. Image quality degradation becomes evident when the imaging dose (approximated with the x-ray tube load) is decreased below 100 total mAs. An imaging dose lower than 40 total mAs leads to a dramatic image degradation, and thus should be used cautiously. Optimal low-dose CBCT scan protocols likely fall in the dose range of 40-100 total mAs, depending on the specific IGRT applications. (2) Among different scan protocols at a constant low-dose level, the super sparse-view reconstruction with the projection number less than 50 is the most challenging case, even with strong regularization. Better image quality can be acquired with low mAs protocols. (3) The optimal scan protocol is the combination of a medium number of projections and a medium level of mAs/view. This is more evident when the dose is around 72.8 total mAs or below and when the ROI is a low-contrast or high-resolution object. Based on our results, the optimal number of projections is around 90 to 120. (4) The clinically acceptable lowest imaging dose level is task dependent. In our study, 72.8 mAs is a safe dose level for visualizing low-contrast objects, while 12.2 total mAs is sufficient for detecting high-contrast objects of diameter greater than 3 mm.

Comparative Study Of Image Enhancement Algorithms For Digital And Film Mammography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delgado-Gonzalez, A.; Sanmiguel, R. E.

2008-08-11

Here we discuss the application of edge enhancement algorithms on images obtained with a Mammography System which has a Selenium Detector and on the other hand, on images obtained from digitized film mammography. Comparative analysis of such images includes the study of technical aspects of image acquisition, storage, compression and display. A protocol for a local database has been created as a result of this study.

Reducing radiation dose to the female breast during conventional and dedicated breast computed tomography

NASA Astrophysics Data System (ADS)

Rupcich, Franco John

The purpose of this study was to quantify the effectiveness of techniques intended to reduce dose to the breast during CT coronary angiography (CTCA) scans with respect to task-based image quality, and to evaluate the effectiveness of optimal energy weighting in improving contrast-to-noise ratio (CNR), and thus the potential for reducing breast dose, during energy-resolved dedicated breast CT. A database quantifying organ dose for several radiosensitive organs irradiated during CTCA, including the breast, was generated using Monte Carlo simulations. This database facilitates estimation of organ-specific dose deposited during CTCA protocols using arbitrary x-ray spectra or tube-current modulation schemes without the need to run Monte Carlo simulations. The database was used to estimate breast dose for simulated CT images acquired for a reference protocol and five protocols intended to reduce breast dose. For each protocol, the performance of two tasks (detection of signals with unknown locations) was compared over a range of breast dose levels using a task-based, signal-detectability metric: the estimator of the area under the exponential free-response relative operating characteristic curve, AFE. For large-diameter/medium-contrast signals, when maintaining equivalent AFE, the 80 kV partial, 80 kV, 120 kV partial, and 120 kV tube-current modulated protocols reduced breast dose by 85%, 81%, 18%, and 6%, respectively, while the shielded protocol increased breast dose by 68%. Results for the small-diameter/high-contrast signal followed similar trends, but with smaller magnitude of the percent changes in dose. The 80 kV protocols demonstrated the greatest reduction to breast dose, however, the subsequent increase in noise may be clinically unacceptable. Tube output for these protocols can be adjusted to achieve more desirable noise levels with lesser dose reduction. The improvement in CNR of optimally projection-based and image-based weighted images relative to photon-counting was investigated for six different energy bin combinations using a bench-top energy-resolving CT system with a cadmium zinc telluride (CZT) detector. The non-ideal spectral response reduced the CNR for the projection-based weighted images, while image-based weighting improved CNR for five out of the six investigated bin combinations, despite this non-ideal response, indicating potential for image-based weighting to reduce breast dose during dedicated breast CT.

Simulation of transmission electron microscope images of biological specimens.

PubMed

Rullgård, H; Ofverstedt, L-G; Masich, S; Daneholt, B; Oktem, O

2011-09-01

We present a new approach to simulate electron cryo-microscope images of biological specimens. The framework for simulation consists of two parts; the first is a phantom generator that generates a model of a specimen suitable for simulation, the second is a transmission electron microscope simulator. The phantom generator calculates the scattering potential of an atomic structure in aqueous buffer and allows the user to define the distribution of molecules in the simulated image. The simulator includes a well defined electron-specimen interaction model based on the scalar Schrödinger equation, the contrast transfer function for optics, and a noise model that includes shot noise as well as detector noise including detector blurring. To enable optimal performance, the simulation framework also includes a calibration protocol for setting simulation parameters. To test the accuracy of the new framework for simulation, we compare simulated images to experimental images recorded of the Tobacco Mosaic Virus (TMV) in vitreous ice. The simulated and experimental images show good agreement with respect to contrast variations depending on dose and defocus. Furthermore, random fluctuations present in experimental and simulated images exhibit similar statistical properties. The simulator has been designed to provide a platform for development of new instrumentation and image processing procedures in single particle electron microscopy, two-dimensional crystallography and electron tomography with well documented protocols and an open source code into which new improvements and extensions are easily incorporated. © 2011 The Authors Journal of Microscopy © 2011 Royal Microscopical Society.

The UNC/UMN Baby Connectome Project (BCP): An overview of the study design and protocol development.

PubMed

Howell, Brittany R; Styner, Martin A; Gao, Wei; Yap, Pew-Thian; Wang, Li; Baluyot, Kristine; Yacoub, Essa; Chen, Geng; Potts, Taylor; Salzwedel, Andrew; Li, Gang; Gilmore, John H; Piven, Joseph; Smith, J Keith; Shen, Dinggang; Ugurbil, Kamil; Zhu, Hongtu; Lin, Weili; Elison, Jed T

2018-03-22

The human brain undergoes extensive and dynamic growth during the first years of life. The UNC/UMN Baby Connectome Project (BCP), one of the Lifespan Connectome Projects funded by NIH, is an ongoing study jointly conducted by investigators at the University of North Carolina at Chapel Hill and the University of Minnesota. The primary objective of the BCP is to characterize brain and behavioral development in typically developing infants across the first 5 years of life. The ultimate goals are to chart emerging patterns of structural and functional connectivity during this period, map brain-behavior associations, and establish a foundation from which to further explore trajectories of health and disease. To accomplish these goals, we are combining state of the art MRI acquisition and analysis techniques, including high-resolution structural MRI (T1-and T2-weighted images), diffusion imaging (dMRI), and resting state functional connectivity MRI (rfMRI). While the overall design of the BCP largely is built on the protocol developed by the Lifespan Human Connectome Project (HCP), given the unique age range of the BCP cohort, additional optimization of imaging parameters and consideration of an age appropriate battery of behavioral assessments were needed. Here we provide the overall study protocol, including approaches for subject recruitment, strategies for imaging typically developing children 0-5 years of age without sedation, imaging protocol and optimization, a description of the battery of behavioral assessments, and QA/QC procedures. Combining HCP inspired neuroimaging data with well-established behavioral assessments during this time period will yield an invaluable resource for the scientific community. Copyright © 2018 Elsevier Inc. All rights reserved.

A Methodology for Anatomic Ultrasound Image Diagnostic Quality Assessment.

PubMed

Hemmsen, Martin Christian; Lange, Theis; Brandt, Andreas Hjelm; Nielsen, Michael Bachmann; Jensen, Jorgen Arendt

2017-01-01

This paper discusses the methods for the assessment of ultrasound image quality based on our experiences with evaluating new methods for anatomic imaging. It presents a methodology to ensure a fair assessment between competing imaging methods using clinically relevant evaluations. The methodology is valuable in the continuing process of method optimization and guided development of new imaging methods. It includes a three phased study plan covering from initial prototype development to clinical assessment. Recommendations to the clinical assessment protocol, software, and statistical analysis are presented. Earlier uses of the methodology has shown that it ensures validity of the assessment, as it separates the influences between developer, investigator, and assessor once a research protocol has been established. This separation reduces confounding influences on the result from the developer to properly reveal the clinical value. This paper exemplifies the methodology using recent studies of synthetic aperture sequential beamforming tissue harmonic imaging.

Contrast medium administration and image acquisition parameters in renal CT angiography: what radiologists need to know

PubMed Central

Saade, Charbel; Deeb, Ibrahim Alsheikh; Mohamad, Maha; Al-Mohiy, Hussain; El-Merhi, Fadi

2016-01-01

Over the last decade, exponential advances in computed tomography (CT) technology have resulted in improved spatial and temporal resolution. Faster image acquisition enabled renal CT angiography to become a viable and effective noninvasive alternative in diagnosing renal vascular pathologies. However, with these advances, new challenges in contrast media administration have emerged. Poor synchronization between scanner and contrast media administration have reduced the consistency in image quality with poor spatial and contrast resolution. Comprehensive understanding of contrast media dynamics is essential in the design and implementation of contrast administration and image acquisition protocols. This review includes an overview of the parameters affecting renal artery opacification and current protocol strategies to achieve optimal image quality during renal CT angiography with iodinated contrast media, with current safety issues highlighted. PMID:26728701

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, Dr. Ira

This grant was awarded in support of Phase 2 of the University of Vermont Center for Biomedical Imaging. Phase 2 outlined several specific aims including: The development of expertise in MRI and fMRI imaging and their applications The acquisition of peer reviewed extramural funding in support of the Center The development of a Core Imaging Advisory Board, fee structure and protocol review and approval process.

Prospective evaluation of a new protocol for the provisional use of perfusion imaging with exercise stress testing.

PubMed

Duvall, W Lane; Savino, John A; Levine, Elliot J; Hermann, Luke K; Croft, Lori B; Henzlova, Milena J

2015-02-01

Previous literature suggests that myocardial perfusion imaging (MPI) adds little to the prognosis of patients who exercise >10 metabolic equivalents (METs) during stress testing. With this in mind, we prospectively tested a provisional injection protocol in emergency department (ED) patients presenting for the evaluation of chest pain in which a patient would not receive an injection of radioisotope if adequate exercise was achieved without symptoms and a negative ECG response. All patients who presented to the ED over a 5-year period who were referred for stress testing as part of their ED evaluation were included. Patients considered for a provisional protocol were: exercise stress, age <65 years, no known coronary artery disease, and an interpretable rest ECG. Criteria for not injecting included a maximal predicted heart rate ≥85%, ≥10 METs of exercise, no anginal symptoms during stress, and no ECG changes. Groups were compared based on stress test results, all-cause and cardiac mortality, follow-up cardiac testing, subsequent revascularization, and cost. A total of 965 patients were eligible with 192 undergoing exercise-only and 773 having perfusion imaging. After 41.6 ± 19.6 months of follow-up, all-cause mortality was similar in the exercise-only versus the exercise plus imaging group (2.6% vs. 2.1%, p = 0.59). There were no cardiac deaths in the exercise-only group. At 1 year there was no difference in the number of repeat functional stress tests (1.6% vs. 2.1%, p = 0.43), fewer angiograms (0% vs. 4.0%, p = 0.002), and a significantly lower cost ($65 ± $332 vs $506 ± $1,991, p = 0.002; values are in US dollars) in the exercise-only group. The radiation exposure in the exercise plus imaging group was 8.4 ± 2.1 mSv. A provisional injection protocol has a very low mortality, few follow-up diagnostic tests, and lower cost compared to standard imaging protocols. If adopted it would decrease radiation exposure, save time and decrease health-care costs without jeopardizing prognosis.

Clinical utility for diffusion MRI sequence in emergency and inpatient spine protocols.

PubMed

Hoch, Michael J; Rispoli, Joanne; Bruno, Mary; Wauchope, Mervin; Lui, Yvonne W; Shepherd, Timothy M

Diffusion imaging of the spine has the potential to change clinical management, but is challenging due to the small size of the cord and susceptibility artifacts from adjacent structures. Reduced field-of-view (rFOV) diffusion can improve image quality by decreasing the echo train length. Over the past 2 years, we have acquired a rFOV diffusion sequence for MRI spine protocols on most inpatients and emergency room patients. We provide selected imaging diagnoses to illustrate the utility of including diffusion spine MRI in clinical practice. Our experiences support using diffusion MRI to improve diagnostic certainty and facilitate prompt treatment or clinical management. Copyright © 2017 Elsevier Inc. All rights reserved.

Using connectome-based predictive modeling to predict individual behavior from brain connectivity

PubMed Central

Shen, Xilin; Finn, Emily S.; Scheinost, Dustin; Rosenberg, Monica D.; Chun, Marvin M.; Papademetris, Xenophon; Constable, R Todd

2017-01-01

Neuroimaging is a fast developing research area where anatomical and functional images of human brains are collected using techniques such as functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and electroencephalography (EEG). Technical advances and large-scale datasets have allowed for the development of models capable of predicting individual differences in traits and behavior using brain connectivity measures derived from neuroimaging data. Here, we present connectome-based predictive modeling (CPM), a data-driven protocol for developing predictive models of brain-behavior relationships from connectivity data using cross-validation. This protocol includes the following steps: 1) feature selection, 2) feature summarization, 3) model building, and 4) assessment of prediction significance. We also include suggestions for visualizing the most predictive features (i.e., brain connections). The final result should be a generalizable model that takes brain connectivity data as input and generates predictions of behavioral measures in novel subjects, accounting for a significant amount of the variance in these measures. It has been demonstrated that the CPM protocol performs equivalently or better than most of the existing approaches in brain-behavior prediction. However, because CPM focuses on linear modeling and a purely data-driven driven approach, neuroscientists with limited or no experience in machine learning or optimization would find it easy to implement the protocols. Depending on the volume of data to be processed, the protocol can take 10–100 minutes for model building, 1–48 hours for permutation testing, and 10–20 minutes for visualization of results. PMID:28182017

Cone-beam volume CT mammographic imaging: feasibility study

NASA Astrophysics Data System (ADS)

Chen, Biao; Ning, Ruola

2001-06-01

X-ray projection mammography, using a film/screen combination or digital techniques, has proven to be the most effective imaging modality for early detection of breast cancer currently available. However, the inherent superimposition of structures makes small carcinoma (a few millimeters in size) difficult to detect in the occultation case or in dense breasts, resulting in a high false positive biopsy rate. The cone-beam x-ray projection based volume imaging using flat panel detectors (FPDs) makes it possible to obtain three-dimensional breast images. This may benefit diagnosis of the structure and pattern of the lesion while eliminating hard compression of the breast. This paper presents a novel cone-beam volume CT mammographic imaging protocol based on the above techniques. Through computer simulation, the key issues of the system and imaging techniques, including the x-ray imaging geometry and corresponding reconstruction algorithms, x-ray characteristics of breast tissues, x-ray setting techniques, the absorbed dose estimation and the quantitative effect of x-ray scattering on image quality, are addressed. The preliminary simulation results support the proposed cone-beam volume CT mammographic imaging modality in respect to feasibility and practicability for mammography. The absorbed dose level is comparable to that of current two-view mammography and would not be a prominent problem for this imaging protocol. Compared to traditional mammography, the proposed imaging protocol with isotropic spatial resolution will potentially provide significantly better low contrast detectability of breast tumors and more accurate location of breast lesions.

Optical coherence tomography: A guide to interpretation of common macular diseases

PubMed Central

Bhende, Muna; Shetty, Sharan; Parthasarathy, Mohana Kuppuswamy; Ramya, S

2018-01-01

Optical coherence tomography is a quick, non invasive and reproducible imaging tool for macular lesions and has become an essential part of retina practice. This review address the common protocols for imaging the macula, basics of image interpretation, features of common macular disorders with clues to differentiate mimickers and an introduction to choroidal imaging. It includes case examples and also a practical algorithm for interpretation. PMID:29283118

SU-G-206-01: A Fully Automated CT Tool to Facilitate Phantom Image QA for Quantitative Imaging in Clinical Trials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wahi-Anwar, M; Lo, P; Kim, H

Purpose: The use of Quantitative Imaging (QI) methods in Clinical Trials requires both verification of adherence to a specified protocol and an assessment of scanner performance under that protocol, which are currently accomplished manually. This work introduces automated phantom identification and image QA measure extraction towards a fully-automated CT phantom QA system to perform these functions and facilitate the use of Quantitative Imaging methods in clinical trials. Methods: This study used a retrospective cohort of CT phantom scans from existing clinical trial protocols - totaling 84 phantoms, across 3 phantom types using various scanners and protocols. The QA system identifiesmore » the input phantom scan through an ensemble of threshold-based classifiers. Each classifier - corresponding to a phantom type - contains a template slice, which is compared to the input scan on a slice-by-slice basis, resulting in slice-wise similarity metric values for each slice compared. Pre-trained thresholds (established from a training set of phantom images matching the template type) are used to filter the similarity distribution, and the slice with the most optimal local mean similarity, with local neighboring slices meeting the threshold requirement, is chosen as the classifier’s matched slice (if it existed). The classifier with the matched slice possessing the most optimal local mean similarity is then chosen as the ensemble’s best matching slice. If the best matching slice exists, image QA algorithm and ROIs corresponding to the matching classifier extracted the image QA measures. Results: Automated phantom identification performed with 84.5% accuracy and 88.8% sensitivity on 84 phantoms. Automated image quality measurements (following standard protocol) on identified water phantoms (n=35) matched user QA decisions with 100% accuracy. Conclusion: We provide a fullyautomated CT phantom QA system consistent with manual QA performance. Further work will include parallel component to automatically verify image acquisition parameters and automated adherence to specifications. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical Systems; Consultant, Samsung Electronics; NIH Grant support from: U01 CA181156.« less

Use of a web-based image reporting and tracking system for assessing abdominal imaging examination quality issues in a single practice.

PubMed

Rosenkrantz, Andrew B; Johnson, Evan; Sanger, Joseph J

2015-10-01

This article presents our local experience in the implementation of a real-time web-based system for reporting and tracking quality issues relating to abdominal imaging examinations. This system allows radiologists to electronically submit examination quality issues during clinical readouts. The submitted information is e-mailed to a designate for the given modality for further follow-up; the designate may subsequently enter text describing their response or action taken, which is e-mailed back to the radiologist. Review of 558 entries over a 6-year period demonstrated documentation of a broad range of examination quality issues, including specific issues relating to protocol deviation, post-processing errors, positioning errors, artifacts, and IT concerns. The most common issues varied among US, CT, MRI, radiography, and fluoroscopy. In addition, the most common issues resulting in a patient recall for repeat imaging (generally related to protocol deviation in MRI and US) were identified. In addition to submitting quality problems, radiologists also commonly used the tool to provide recognition of a well-performed examination. An electronic log of actions taken in response to radiologists' submissions indicated that both positive and negative feedback were commonly communicated to the performing technologist. Information generated using the tool can be used to guide subsequent quality improvement initiatives within a practice, including continued protocol standardization as well as education of technologists in the optimization of abdominal imaging examinations.

Zoom Reconstruction Tool: Evaluation of Image Quality and Influence on the Diagnosis of Root Fracture.

PubMed

Queiroz, Polyane Mazucatto; Santaella, Gustavo Machado; Capelozza, Ana Lúcia Alvares; Rosalen, Pedro Luiz; Freitas, Deborah Queiroz; Haiter-Neto, Francisco

2018-04-01

This study evaluated the image quality and the diagnosis of root fractures when using the Zoom Reconstruction tool (J Morita, Kyoto, Japan). A utility wax phantom with a metal sample inside was used for objective evaluation, and a mandible with 27 single-rooted teeth (with and without obturation and with and without vertical or horizontal fractures) was used for diagnostic evaluation. The images were acquired in 3 protocols: protocol 1, field of view (FOV) of 4 × 4 cm and a voxel size of 0.08 mm; protocol 2, FOV of 10 × 10 cm and a voxel size of 0.2 mm; and protocol 3, Zoom Reconstruction of images from protocol 2 (FOV of 4 × 4 cm and a voxel size of 0.08 mm). The objective evaluation was achieved by measuring the image noise, and the diagnosis of fractures was performed by 3 evaluators. The area under the receiver operating characteristic curve was used to calculate accuracy, and analysis of variance compared the accuracy and image quality of the protocols. Regarding quality, protocol 1 was superior to protocol 2 (P < .0001) and Zoom Reconstruction (P < .0001). Additionally, images of protocol 2 presented less noise than the Zoom Reconstruction image (P < .0001); however, for diagnosis, Zoom Reconstruction was superior in relation to protocol 2 (P = .011) and did not differ from protocol 1 (P = .228) for the diagnosis of a vertical root fracture in filled teeth. The Zoom Reconstruction tool allows better accuracy for vertical root fracture detection in filled teeth, making it possible to obtain a higher-resolution image from a lower-resolution examination without having to expose the patient to more radiation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Radiation dose to patients and image quality evaluation from coronary 256-slice computed tomographic angiography

NASA Astrophysics Data System (ADS)

Chen, Liang-Kuang; Wu, Tung-Hsin; Yang, Ching-Ching; Tsai, Chia-Jung; Lee, Jason J. S.

2010-07-01

The aim of this study is to assess radiation dose and the corresponding image quality from suggested CT protocols which depends on different mean heart rate and high heart rate variability by using 256-slice CT. Fifty consecutive patients referred for a cardiac CT examination were included in this study. All coronary computed tomographic angiography (CCTA) examinations were performed on a 256-slice CT scanner with one of five different protocols: retrospective ECG-gating (RGH) with full dose exposure in all R-R intervals (protocol A), RGH of 30-80% pulsing window with tube current modulation (B), RGH of 78±5% pulsing window with tube current modulation (C), prospective ECG-triggering (PGT) of 78% R-R interval with 5% padding window (D) and PGT of 78% R-R interval without padding window (E). Radiation dose parameters and image quality scoring were determined and compared. In this study, no significant differences were found in comparison on image quality of the five different protocols. Protocol A obtained the highest radiation dose comparing with those of protocols B, C, D and E by a factor of 1.6, 2.4, 2.5 and 4.3, respectively ( p<0.001), which were ranged between 2.7 and 11.8 mSv. The PGT could significantly reduce radiation dose delivered to patients, as compared to the RGH. However, the use of PGT has limitations and is only good in assessing cases with lower mean heart rate and stable heart rate variability. With higher mean heart rate and high heart rate variability circumstances, the RGH within 30-80% of R-R interval pulsing window is suggested as a feasible technique for assessing diagnostic performance.

Achieving High Throughput for Data Transfer over ATM Networks

NASA Technical Reports Server (NTRS)

Johnson, Marjory J.; Townsend, Jeffrey N.

1996-01-01

File-transfer rates for ftp are often reported to be relatively slow, compared to the raw bandwidth available in emerging gigabit networks. While a major bottleneck is disk I/O, protocol issues impact performance as well. Ftp was developed and optimized for use over the TCP/IP protocol stack of the Internet. However, TCP has been shown to run inefficiently over ATM. In an effort to maximize network throughput, data-transfer protocols can be developed to run over UDP or directly over IP, rather than over TCP. If error-free transmission is required, techniques for achieving reliable transmission can be included as part of the transfer protocol. However, selected image-processing applications can tolerate a low level of errors in images that are transmitted over a network. In this paper we report on experimental work to develop a high-throughput protocol for unreliable data transfer over ATM networks. We attempt to maximize throughput by keeping the communications pipe full, but still keep packet loss under five percent. We use the Bay Area Gigabit Network Testbed as our experimental platform.

Sedation protocol with fasting and shorter sleep leads to magnetic resonance imaging success.

PubMed

Kimiya, Takahisa; Sekiguchi, Shinichiro; Yagihashi, Tatsuhiko; Arai, Mie; Takahashi, Hirotaka; Takahashi, Takao

2017-10-01

Young children undergoing magnetic resonance imaging (MRI) require sedation. In June 2013, Tokyo Metropolitan Ohtsuka Hospital (TMOH) introduced an oral sedation protocol for young children undergoing MRI; the protocol included instructions on fasting before sedation, and recommended a shorter duration of sleep the night before MRI. We compared the MRI success rate before and after the introduction of this protocol. The eligible subjects were children under 3 years old who underwent MRI by appointment at TMOH between October 2012 and March 2014, under sedation with triclofos sodium. All those who underwent MRI in or after June 2013 were enrolled prospectively as a post-protocol group. All patients who underwent MRI before June 2013 were enrolled retrospectively as a pre-protocol group, with data collected from chart review. Seventy-four patients were enrolled in the post-protocol group, and 42 in the pre-protocol group. The MRI success rate was significantly higher in the post-protocol group than in the pre-protocol group (98.7% vs 88.1%), as was the rate of on-time starting of MRI (86.5% vs 71.4%). The post-protocol group woke up earlier on the day of examination (6:18 a.m. vs 6:43 a.m.), resulting in a significantly longer time between awakening and the beginning of sedation (289.8 min vs 265.9 min), and a significantly shorter average duration of sleep on the previous night (504.8 min vs 532.3 min). Implementation of a hospital-wide sedation protocol for young children undergoing MRI significantly improved the MRI success rate. © 2017 Japan Pediatric Society.

Development of a bedside viable ultrasound protocol to quantify appendicular lean tissue mass.

PubMed

Paris, Michael T; Lafleur, Benoit; Dubin, Joel A; Mourtzakis, Marina

2017-10-01

Ultrasound is a non-invasive and readily available tool that can be prospectively applied at the bedside to assess muscle mass in clinical settings. The four-site protocol, which images two anatomical sites on each quadriceps, may be a viable bedside method, but its ability to predict musculature has not been compared against whole-body reference methods. Our primary objectives were to (i) compare the four-site protocol's ability to predict appendicular lean tissue mass from dual-energy X-ray absorptiometry; (ii) optimize the predictability of the four-site protocol with additional anatomical muscle thicknesses and easily obtained covariates; and (iii) assess the ability of the optimized protocol to identify individuals with low lean tissue mass. This observational cross-sectional study recruited 96 university and community dwelling adults. Participants underwent ultrasound scans for assessment of muscle thickness and whole-body dual-energy X-ray absorptiometry scans for assessment of appendicular lean tissue. Ultrasound protocols included (i) the nine-site protocol, which images nine anterior and posterior muscle groups in supine and prone positions, and (ii) the four-site protocol, which images two anterior sites on each quadriceps muscle group in a supine position. The four-site protocol was strongly associated (R 2  = 0.72) with appendicular lean tissue mass, but Bland-Altman analysis displayed wide limits of agreement (-5.67, 5.67 kg). Incorporating the anterior upper arm muscle thickness, and covariates age and sex, alongside the four-site protocol, improved the association (R 2  = 0.91) with appendicular lean tissue and displayed narrower limits of agreement (-3.18, 3.18 kg). The optimized protocol demonstrated a strong ability to identify low lean tissue mass (area under the curve = 0.89). The four-site protocol can be improved with the addition of the anterior upper arm muscle thickness, sex, and age when predicting appendicular lean tissue mass. This optimized protocol can accurately identify low lean tissue mass, while still being easily applied at the bedside. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

Development of a bedside viable ultrasound protocol to quantify appendicular lean tissue mass

PubMed Central

Paris, Michael T.; Lafleur, Benoit; Dubin, Joel A.

2017-01-01

Abstract Background Ultrasound is a non‐invasive and readily available tool that can be prospectively applied at the bedside to assess muscle mass in clinical settings. The four‐site protocol, which images two anatomical sites on each quadriceps, may be a viable bedside method, but its ability to predict musculature has not been compared against whole‐body reference methods. Our primary objectives were to (i) compare the four‐site protocol's ability to predict appendicular lean tissue mass from dual‐energy X‐ray absorptiometry; (ii) optimize the predictability of the four‐site protocol with additional anatomical muscle thicknesses and easily obtained covariates; and (iii) assess the ability of the optimized protocol to identify individuals with low lean tissue mass. Methods This observational cross‐sectional study recruited 96 university and community dwelling adults. Participants underwent ultrasound scans for assessment of muscle thickness and whole‐body dual‐energy X‐ray absorptiometry scans for assessment of appendicular lean tissue. Ultrasound protocols included (i) the nine‐site protocol, which images nine anterior and posterior muscle groups in supine and prone positions, and (ii) the four‐site protocol, which images two anterior sites on each quadriceps muscle group in a supine position. Results The four‐site protocol was strongly associated (R 2 = 0.72) with appendicular lean tissue mass, but Bland–Altman analysis displayed wide limits of agreement (−5.67, 5.67 kg). Incorporating the anterior upper arm muscle thickness, and covariates age and sex, alongside the four‐site protocol, improved the association (R 2 = 0.91) with appendicular lean tissue and displayed narrower limits of agreement (−3.18, 3.18 kg). The optimized protocol demonstrated a strong ability to identify low lean tissue mass (area under the curve = 0.89). Conclusions The four‐site protocol can be improved with the addition of the anterior upper arm muscle thickness, sex, and age when predicting appendicular lean tissue mass. This optimized protocol can accurately identify low lean tissue mass, while still being easily applied at the bedside. PMID:28722298

Augmented Quadruple-Phase Contrast Media Administration and Triphasic Scan Protocol Increases Image Quality at Reduced Radiation Dose During Computed Tomography Urography.

PubMed

Saade, Charbel; Mohamad, May; Kerek, Racha; Hamieh, Nadine; Alsheikh Deeb, Ibrahim; El-Achkar, Bassam; Tamim, Hani; Abdul Razzak, Farah; Haddad, Maurice; Abi-Ghanem, Alain S; El-Merhi, Fadi

The aim of this article was to investigate the opacification of the renal vasculature and the urogenital system during computed tomography urography by using a quadruple-phase contrast media in a triphasic scan protocol. A total of 200 patients with possible urinary tract abnormalities were equally divided between 2 protocols. Protocol A used the conventional single bolus and quadruple-phase scan protocol (pre, arterial, venous, and delayed), retrospectively. Protocol B included a quadruple-phase contrast media injection with a triphasic scan protocol (pre, arterial and combined venous, and delayed), prospectively. Each protocol used 100 mL contrast and saline at a flow rate of 4.5 mL. Attenuation profiles and contrast-to-noise ratio of the renal arteries, veins, and urogenital tract were measured. Effective radiation dose calculation, data analysis by independent sample t test, receiver operating characteristic, and visual grading characteristic analyses were performed. In arterial circulation, only the inferior interlobular arteries in both protocols showed a statistical significance (P < 0.05). Venously, the inferior vena cava, proximal and distal renal veins demonstrated a significant opacification reduction in protocol B than in protocol A (P < 0.001). Protocol B showed a significantly higher mean contrast-to-noise ratio than protocol A (protocol B: 22.68 ± 13.72; protocol A: 14.75 ± 5.76; P < 0.001). Radiation dose was significantly reduced in protocol B (7.38 ± 2.22 mSv) than in protocol A (12.28 ± 2.72 mSv) (P < 0.001). Visual grading characteristic (P < 0.027) and receiver operating characteristic (P < 0.0001) analyses demonstrated a significant preference for protocol B. In computed tomography urography, augmented quadruple-phase contrast media and triphasic scan protocol usage increases the image quality at a reduced radiation dose.

Scoring System for the Management of Acute Gallstone Pancreatitis: Cost Analysis of a Prospective Study.

PubMed

Prigoff, Jake G; Swain, Gary W; Divino, Celia M

2016-05-01

Predicting the presence of a persistent common bile duct (CBD) stone is a difficult and expensive task. The aim of this study is to determine if a previously described protocol-based scoring system is a cost-effective strategy. The protocol includes all patients with gallstone pancreatitis and stratifies them based on laboratory values and imaging to high, medium, and low likelihood of persistent stones. The patient's stratification then dictates the next course of management. A decision analytic model was developed to compare the costs for patients who followed the protocol versus those that did not. Clinical data model inputs were obtained from a prospective study conducted at The Mount Sinai Medical Center to validate the protocol from Oct 2009 to May 2013. The study included all patients presenting with gallstone pancreatitis regardless of disease severity. Seventy-three patients followed the proposed protocol and 32 did not. The protocol group cost an average of $14,962/patient and the non-protocol group cost $17,138/patient for procedural costs. Mean length of stay for protocol and non-protocol patients was 5.6 and 7.7 days, respectively. The proposed protocol is a cost-effective way to determine the course for patients with gallstone pancreatitis, reducing total procedural costs over 12 %.

Digital Breast Tomosynthesis: Observer Performance of Clustered Microcalcification Detection on Breast Phantom Images Acquired with an Experimental System Using Variable Scan Angles, Angular Increments, and Number of Projection Views

PubMed Central

Goodsitt, Mitchell M.; Helvie, Mark A.; Zelakiewicz, Scott; Schmitz, Andrea; Noroozian, Mitra; Paramagul, Chintana; Roubidoux, Marilyn A.; Nees, Alexis V.; Neal, Colleen H.; Carson, Paul; Lu, Yao; Hadjiiski, Lubomir; Wei, Jun

2014-01-01

Purpose To investigate the dependence of microcalcification cluster detectability on tomographic scan angle, angular increment, and number of projection views acquired at digital breast tomosynthesis (DBTdigital breast tomosynthesis). Materials and Methods A prototype DBTdigital breast tomosynthesis system operated in step-and-shoot mode was used to image breast phantoms. Four 5-cm-thick phantoms embedded with 81 simulated microcalcification clusters of three speck sizes (subtle, medium, and obvious) were imaged by using a rhodium target and rhodium filter with 29 kV, 50 mAs, and seven acquisition protocols. Fixed angular increments were used in four protocols (denoted as scan angle, angular increment, and number of projection views, respectively: 16°, 1°, and 17; 24°, 3°, and nine; 30°, 3°, and 11; and 60°, 3°, and 21), and variable increments were used in three (40°, variable, and 13; 40°, variable, and 15; and 60°, variable, and 21). The reconstructed DBTdigital breast tomosynthesis images were interpreted by six radiologists who located the microcalcification clusters and rated their conspicuity. Results The mean sensitivity for detection of subtle clusters ranged from 80% (22.5 of 28) to 96% (26.8 of 28) for the seven DBTdigital breast tomosynthesis protocols; the highest sensitivity was achieved with the 16°, 1°, and 17 protocol (96%), but the difference was significant only for the 60°, 3°, and 21 protocol (80%, P < .002) and did not reach significance for the other five protocols (P = .01–.15). The mean sensitivity for detection of medium and obvious clusters ranged from 97% (28.2 of 29) to 100% (24 of 24), but the differences fell short of significance (P = .08 to >.99). The conspicuity of subtle and medium clusters with the 16°, 1°, and 17 protocol was rated higher than those with other protocols; the differences were significant for subtle clusters with the 24°, 3°, and nine protocol and for medium clusters with 24°, 3°, and nine; 30°, 3°, and 11; 60°, 3° and 21; and 60°, variable, and 21 protocols (P < .002). Conclusion With imaging that did not include x-ray source motion or patient motion during acquisition of the projection views, narrow-angle DBTdigital breast tomosynthesis provided higher sensitivity and conspicuity than wide-angle DBTdigital breast tomosynthesis for subtle microcalcification clusters. © RSNA, 2014 PMID:25007048

New Protocol for Skin Landmark Registration in Image-Guided Neurosurgery: Technical Note.

PubMed

Gerard, Ian J; Hall, Jeffery A; Mok, Kelvin; Collins, D Louis

2015-09-01

Newer versions of the commercial Medtronic StealthStation allow the use of only 8 landmark pairs for patient-to-image registration as opposed to 9 landmarks in older systems. The choice of which landmark pair to drop in these newer systems can have an effect on the quality of the patient-to-image registration. To investigate 4 landmark registration protocols based on 8 landmark pairs and compare the resulting registration accuracy with a 9-landmark protocol. Four different protocols were tested on both phantoms and patients. Two of the protocols involved using 4 ear landmarks and 4 facial landmarks and the other 2 involved using 3 ear landmarks and 5 facial landmarks. Both the fiducial registration error and target registration error were evaluated for each of the different protocols to determine any difference between them and the 9-landmark protocol. No difference in fiducial registration error was found between any of the 8-landmark protocols and the 9-landmark protocol. A significant decrease (P < .05) in target registration error was found when using a protocol based on 4 ear landmarks and 4 facial landmarks compared with the other protocols based on 3 ear landmarks. When using 8 landmarks to perform the patient-to-image registration, the protocol using 4 ear landmarks and 4 facial landmarks greatly outperformed the other 8-landmark protocols and 9-landmark protocol, resulting in the lowest target registration error.

Towards a five-minute comprehensive cardiac MR examination using highly accelerated parallel imaging with a 32-element coil array: feasibility and initial comparative evaluation.

PubMed

Xu, Jian; Kim, Daniel; Otazo, Ricardo; Srichai, Monvadi B; Lim, Ruth P; Axel, Leon; Mcgorty, Kelly Anne; Niendorf, Thoralf; Sodickson, Daniel K

2013-07-01

To evaluate the feasibility and perform initial comparative evaluations of a 5-minute comprehensive whole-heart magnetic resonance imaging (MRI) protocol with four image acquisition types: perfusion (PERF), function (CINE), coronary artery imaging (CAI), and late gadolinium enhancement (LGE). This study protocol was Health Insurance Portability and Accountability Act (HIPAA)-compliant and Institutional Review Board-approved. A 5-minute comprehensive whole-heart MRI examination protocol (Accelerated) using 6-8-fold-accelerated volumetric parallel imaging was incorporated into and compared with a standard 2D clinical routine protocol (Standard). Following informed consent, 20 patients were imaged with both protocols. Datasets were reviewed for image quality using a 5-point Likert scale (0 = non-diagnostic, 4 = excellent) in blinded fashion by two readers. Good image quality with full whole-heart coverage was achieved using the accelerated protocol, particularly for CAI, although significant degradations in quality, as compared with traditional lengthy examinations, were observed for the other image types. Mean total scan time was significantly lower for the Accelerated as compared to Standard protocols (28.99 ± 4.59 min vs. 1.82 ± 0.05 min, P < 0.05). Overall image quality for the Standard vs. Accelerated protocol was 3.67 ± 0.29 vs. 1.5 ± 0.51 (P < 0.005) for PERF, 3.48 ± 0.64 vs. 2.6 ± 0.68 (P < 0.005) for CINE, 2.35 ± 1.01 vs. 2.48 ± 0.68 (P = 0.75) for CAI, and 3.67 ± 0.42 vs. 2.67 ± 0.84 (P < 0.005) for LGE. Diagnostic image quality for Standard vs. Accelerated protocols was 20/20 (100%) vs. 10/20 (50%) for PERF, 20/20 (100%) vs. 18/20 (90%) for CINE, 18/20 (90%) vs. 18/20 (90%) for CAI, and 20/20 (100%) vs. 18/20 (90%) for LGE. This study demonstrates the technical feasibility and promising image quality of 5-minute comprehensive whole-heart cardiac examinations, with simplified scan prescription and high spatial and temporal resolution enabled by highly parallel imaging technology. The study also highlights technical hurdles that remain to be addressed. Although image quality remained diagnostic for most scan types, the reduced image quality of PERF, CINE, and LGE scans in the Accelerated protocol remain a concern. Copyright © 2012 Wiley Periodicals, Inc.

Very Low Intravenous Contrast Volume Protocol for Computed Tomography Angiography Providing Comprehensive Cardiac and Vascular Assessment Prior to Transcatheter Aortic Valve Replacement in Patients with Chronic Kidney Disease

PubMed Central

Pulerwitz, Todd C.; Khalique, Omar K.; Nazif, Tamim N.; Rozenshtein, Anna; Pearson, Gregory D.N.; Hahn, Rebecca T.; Vahl, Torsten P.; Kodali, Susheel K.; George, Isaac; Leon, Martin B.; D'Souza, Belinda; Po, Ming Jack; Einstein, Andrew J.

2016-01-01

Background Transcatheter aortic valve replacement (TAVR) is a lifesaving procedure for many patients high risk for surgical aortic valve replacement. The prevalence of chronic kidney disease (CKD) is high in this population, and thus a very low contrast volume (VLCV) computed tomography angiography (CTA) protocol providing comprehensive cardiac and vascular imaging would be valuable. Methods 52 patients with severe, symptomatic aortic valve disease, undergoing pre-TAVR CTA assessment from 2013-4 at Columbia University Medical Center were studied, including all 26 patients with CKD (eGFR<30mL/min) who underwent a novel VLCV protocol (20mL of iohexol at 2.5mL/s), and 26 standard-contrast-volume (SCV) protocol patients. Using a 320-slice volumetric scanner, the protocol included ECG-gated volume scanning of the aortic root followed by medium-pitch helical vascular scanning through the femoral arteries. Two experienced cardiologists performed aortic annulus and root measurements. Vascular image quality was assessed by two radiologists using a 4-point scale. Results VLCV patients had mean(±SD) age 86±6.5, BMI 23.9±3.4 kg/m2 with 54% men; SCV patients age 83±8.8, BMI 28.7±5.3 kg/m2, 65% men. There was excellent intra- and inter-observer agreement for annular and root measurements, and excellent agreement with 3D-transesophageal echocardiographic measurements. Both radiologists found diagnostic-quality vascular imaging in 96% of VLCV and 100% of SCV cases, with excellent inter-observer agreement. Conclusions This study is the first of its kind to report the feasibility and reproducibility of measurements for a VLCV protocol for comprehensive pre-TAVR CTA. There was excellent agreement of cardiac measurements and almost all studies were diagnostic quality for vascular access assessment. PMID:27061253

Echo-Planar Imaging-Based, J-Resolved Spectroscopic Imaging for Improved Metabolite Detection in Prostate Cancer

DTIC Science & Technology

2015-10-01

cancer is through imaging techniques including ultrasound , computed tomography (CT), and magnetic resonance imaging (MRI) with or without the help...performed at least 8 weeks after transrectal ultrasound -guided sextant biopsy. The entire protocol was ap- proved by the Institutional Review Board...volume of interest (VOI) was localized using three slice-selective radiofrequency (RF) pulses (90°–180°–180°) (Fig. 1). The total time for the

Design of a functional cyclic HSV1-TK reporter and its application to PET imaging of apoptosis

PubMed Central

Wang, Zhe; Wang, Fu; Hida, Naoki; Kiesewetter, Dale O; Tian, Jie; Niu, Gang; Chen, Xiaoyuan

2017-01-01

Positron emission tomography (PET) is a sensitive and noninvasive imaging method that is widely used to explore molecular events in living subjects. PET can precisely and quantitatively evaluate cellular apoptosis, which has a crucial role in various physiological and pathological processes. In this protocol, we describe the design and use of an engineered cyclic herpes simplex virus 1–thymidine kinase (HSV1-TK) PET reporter whose kinase activity is specifically switched on by apoptosis. The expression of cyclic TK (cTK) in healthy cells leads to inactive product, whereas the activation of apoptosis through the caspase-3 pathway cleaves cTK, thus restoring its activity and enabling PET imaging. In addition to detailing the design and construction of the cTK plasmid in this protocol, we include assays for evaluating the function and specificity of the cTK reporter in apoptotic cells, such as assays for measuring the cell uptake of PET tracer in apoptotic cells, correlating doxorubicin (Dox)-induced cell apoptosis to cTK function recovery, and in vivo PET imaging of cancer cell apoptosis, and we also include corresponding data acquisition methods. The time to build the entire cTK reporter is ~2–3 weeks. The selection of a stable cancer cell line takes ~4–6 weeks. The time to implement assays regarding cTK function in apoptotic cells and the in vivo imaging varies depending on the experiment. The cyclization strategy described in this protocol can also be adapted to create other reporter systems for broad biomedical applications. PMID:25927390

Stent deployment protocol for optimized real-time visualization during endovascular neurosurgery.

PubMed

Silva, Michael A; See, Alfred P; Dasenbrock, Hormuzdiyar H; Ashour, Ramsey; Khandelwal, Priyank; Patel, Nirav J; Frerichs, Kai U; Aziz-Sultan, Mohammad A

2017-05-01

Successful application of endovascular neurosurgery depends on high-quality imaging to define the pathology and the devices as they are being deployed. This is especially challenging in the treatment of complex cases, particularly in proximity to the skull base or in patients who have undergone prior endovascular treatment. The authors sought to optimize real-time image guidance using a simple algorithm that can be applied to any existing fluoroscopy system. Exposure management (exposure level, pulse management) and image post-processing parameters (edge enhancement) were modified from traditional fluoroscopy to improve visualization of device position and material density during deployment. Examples include the deployment of coils in small aneurysms, coils in giant aneurysms, the Pipeline embolization device (PED), the Woven EndoBridge (WEB) device, and carotid artery stents. The authors report on the development of the protocol and their experience using representative cases. The stent deployment protocol is an image capture and post-processing algorithm that can be applied to existing fluoroscopy systems to improve real-time visualization of device deployment without hardware modifications. Improved image guidance facilitates aneurysm coil packing and proper positioning and deployment of carotid artery stents, flow diverters, and the WEB device, especially in the context of complex anatomy and an obscured field of view.

A priori collaboration in population imaging: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement consortium.

PubMed

Adams, Hieab H H; Hilal, Saima; Schwingenschuh, Petra; Wittfeld, Katharina; van der Lee, Sven J; DeCarli, Charles; Vernooij, Meike W; Katschnig-Winter, Petra; Habes, Mohamad; Chen, Christopher; Seshadri, Sudha; van Duijn, Cornelia M; Ikram, M Kamran; Grabe, Hans J; Schmidt, Reinhold; Ikram, M Arfan

2015-12-01

Virchow-Robin spaces (VRS), or perivascular spaces, are compartments of interstitial fluid enclosing cerebral blood vessels and are potential imaging markers of various underlying brain pathologies. Despite a growing interest in the study of enlarged VRS, the heterogeneity in rating and quantification methods combined with small sample sizes have so far hampered advancement in the field. The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement (UNIVRSE) consortium was established with primary aims to harmonize rating and analysis (www.uconsortium.org). The UNIVRSE consortium brings together 13 (sub)cohorts from five countries, totaling 16,000 subjects and over 25,000 scans. Eight different magnetic resonance imaging protocols were used in the consortium. VRS rating was harmonized using a validated protocol that was developed by the two founding members, with high reliability independent of scanner type, rater experience, or concomitant brain pathology. Initial analyses revealed risk factors for enlarged VRS including increased age, sex, high blood pressure, brain infarcts, and white matter lesions, but this varied by brain region. Early collaborative efforts between cohort studies with respect to data harmonization and joint analyses can advance the field of population (neuro)imaging. The UNIVRSE consortium will focus efforts on other potential correlates of enlarged VRS, including genetics, cognition, stroke, and dementia.

Protocols for Image Processing based Underwater Inspection of Infrastructure Elements

NASA Astrophysics Data System (ADS)

O'Byrne, Michael; Ghosh, Bidisha; Schoefs, Franck; Pakrashi, Vikram

2015-07-01

Image processing can be an important tool for inspecting underwater infrastructure elements like bridge piers and pile wharves. Underwater inspection often relies on visual descriptions of divers who are not necessarily trained in specifics of structural degradation and the information may often be vague, prone to error or open to significant variation of interpretation. Underwater vehicles, on the other hand can be quite expensive to deal with for such inspections. Additionally, there is now significant encouragement globally towards the deployment of more offshore renewable wind turbines and wave devices and the requirement for underwater inspection can be expected to increase significantly in the coming years. While the merit of image processing based assessment of the condition of underwater structures is understood to a certain degree, there is no existing protocol on such image based methods. This paper discusses and describes an image processing protocol for underwater inspection of structures. A stereo imaging image processing method is considered in this regard and protocols are suggested for image storage, imaging, diving, and inspection. A combined underwater imaging protocol is finally presented which can be used for a variety of situations within a range of image scenes and environmental conditions affecting the imaging conditions. An example of detecting marine growth is presented of a structure in Cork Harbour, Ireland.

Direct comparison between confocal and multiphoton microscopy for rapid histopathological evaluation of unfixed human breast tissue.

PubMed

Yoshitake, Tadayuki; Giacomelli, Michael G; Cahill, Lucas C; Schmolze, Daniel B; Vardeh, Hilde; Faulkner-Jones, Beverly E; Connolly, James L; Fujimoto, James G

2016-12-01

Rapid histopathological examination of surgical specimen margins using fluorescence microscopy during breast conservation therapy has the potential to reduce the rate of positive margins on postoperative histopathology and the need for repeat surgeries. To assess the suitability of imaging modalities, we perform a direct comparison between confocal fluorescence microscopy and multiphoton microscopy for imaging unfixed tissue and compare to paraffin-embedded histology. An imaging protocol including dual channel detection of two contrast agents to implement virtual hematoxylin and eosin images is introduced that provides high quality imaging under both one and two photon excitation. Corresponding images of unfixed human breast tissue show that both confocal and multiphoton microscopy can reproduce the appearance of conventional histology without the need for physical sectioning. We further compare normal breast tissue and invasive cancer specimens imaged at multiple magnifications, and assess the effects of photobleaching for both modalities using the staining protocol. The results demonstrate that confocal fluorescence microscopy is a promising and cost-effective alternative to multiphoton microscopy for rapid histopathological evaluation of ex vivo breast tissue.

Direct comparison between confocal and multiphoton microscopy for rapid histopathological evaluation of unfixed human breast tissue

PubMed Central

Yoshitake, Tadayuki; Giacomelli, Michael G.; Cahill, Lucas C.; Schmolze, Daniel B.; Vardeh, Hilde; Faulkner-Jones, Beverly E.; Connolly, James L.; Fujimoto, James G.

2016-01-01

Abstract. Rapid histopathological examination of surgical specimen margins using fluorescence microscopy during breast conservation therapy has the potential to reduce the rate of positive margins on postoperative histopathology and the need for repeat surgeries. To assess the suitability of imaging modalities, we perform a direct comparison between confocal fluorescence microscopy and multiphoton microscopy for imaging unfixed tissue and compare to paraffin-embedded histology. An imaging protocol including dual channel detection of two contrast agents to implement virtual hematoxylin and eosin images is introduced that provides high quality imaging under both one and two photon excitation. Corresponding images of unfixed human breast tissue show that both confocal and multiphoton microscopy can reproduce the appearance of conventional histology without the need for physical sectioning. We further compare normal breast tissue and invasive cancer specimens imaged at multiple magnifications, and assess the effects of photobleaching for both modalities using the staining protocol. The results demonstrate that confocal fluorescence microscopy is a promising and cost-effective alternative to multiphoton microscopy for rapid histopathological evaluation of ex vivo breast tissue. PMID:28032121

Direct comparison between confocal and multiphoton microscopy for rapid histopathological evaluation of unfixed human breast tissue

NASA Astrophysics Data System (ADS)

Yoshitake, Tadayuki; Giacomelli, Michael G.; Cahill, Lucas C.; Schmolze, Daniel B.; Vardeh, Hilde; Faulkner-Jones, Beverly E.; Connolly, James L.; Fujimoto, James G.

2016-12-01

Rapid histopathological examination of surgical specimen margins using fluorescence microscopy during breast conservation therapy has the potential to reduce the rate of positive margins on postoperative histopathology and the need for repeat surgeries. To assess the suitability of imaging modalities, we perform a direct comparison between confocal fluorescence microscopy and multiphoton microscopy for imaging unfixed tissue and compare to paraffin-embedded histology. An imaging protocol including dual channel detection of two contrast agents to implement virtual hematoxylin and eosin images is introduced that provides high quality imaging under both one and two photon excitation. Corresponding images of unfixed human breast tissue show that both confocal and multiphoton microscopy can reproduce the appearance of conventional histology without the need for physical sectioning. We further compare normal breast tissue and invasive cancer specimens imaged at multiple magnifications, and assess the effects of photobleaching for both modalities using the staining protocol. The results demonstrate that confocal fluorescence microscopy is a promising and cost-effective alternative to multiphoton microscopy for rapid histopathological evaluation of ex vivo breast tissue.

Infrared thermal imaging in medicine.

PubMed

Ring, E F J; Ammer, K

2012-03-01

This review describes the features of modern infrared imaging technology and the standardization protocols for thermal imaging in medicine. The technique essentially uses naturally emitted infrared radiation from the skin surface. Recent studies have investigated the influence of equipment and the methods of image recording. The credibility and acceptance of thermal imaging in medicine is subject to critical use of the technology and proper understanding of thermal physiology. Finally, we review established and evolving medical applications for thermal imaging, including inflammatory diseases, complex regional pain syndrome and Raynaud's phenomenon. Recent interest in the potential applications for fever screening is described, and some other areas of medicine where some research papers have included thermal imaging as an assessment modality. In certain applications thermal imaging is shown to provide objective measurement of temperature changes that are clinically significant.

Atlas-based analysis of cardiac shape and function: correction of regional shape bias due to imaging protocol for population studies.

PubMed

Medrano-Gracia, Pau; Cowan, Brett R; Bluemke, David A; Finn, J Paul; Kadish, Alan H; Lee, Daniel C; Lima, Joao A C; Suinesiaputra, Avan; Young, Alistair A

2013-09-13

Cardiovascular imaging studies generate a wealth of data which is typically used only for individual study endpoints. By pooling data from multiple sources, quantitative comparisons can be made of regional wall motion abnormalities between different cohorts, enabling reuse of valuable data. Atlas-based analysis provides precise quantification of shape and motion differences between disease groups and normal subjects. However, subtle shape differences may arise due to differences in imaging protocol between studies. A mathematical model describing regional wall motion and shape was used to establish a coordinate system registered to the cardiac anatomy. The atlas was applied to data contributed to the Cardiac Atlas Project from two independent studies which used different imaging protocols: steady state free precession (SSFP) and gradient recalled echo (GRE) cardiovascular magnetic resonance (CMR). Shape bias due to imaging protocol was corrected using an atlas-based transformation which was generated from a set of 46 volunteers who were imaged with both protocols. Shape bias between GRE and SSFP was regionally variable, and was effectively removed using the atlas-based transformation. Global mass and volume bias was also corrected by this method. Regional shape differences between cohorts were more statistically significant after removing regional artifacts due to imaging protocol bias. Bias arising from imaging protocol can be both global and regional in nature, and is effectively corrected using an atlas-based transformation, enabling direct comparison of regional wall motion abnormalities between cohorts acquired in separate studies.

The preparation of Drosophila embryos for live-imaging using the hanging drop protocol.

PubMed

Reed, Bruce H; McMillan, Stephanie C; Chaudhary, Roopali

2009-03-13

Green fluorescent protein (GFP)-based timelapse live-imaging is a powerful technique for studying the genetic regulation of dynamic processes such as tissue morphogenesis, cell-cell adhesion, or cell death. Drosophila embryos expressing GFP are readily imaged using either stereoscopic or confocal microscopy. A goal of any live-imaging protocol is to minimize detrimental effects such as dehydration and hypoxia. Previous protocols for preparing Drosophila embryos for live-imaging analysis have involved placing dechorionated embryos in halocarbon oil and sandwiching them between a halocarbon gas-permeable membrane and a coverslip. The introduction of compression through mounting embryos in this manner represents an undesirable complication for any biomechanical-based analysis of morphogenesis. Our method, which we call the hanging drop protocol, results in excellent viability of embryos during live imaging and does not require that embryos be compressed. Briefly, the hanging drop protocol involves the placement of embryos in a drop of halocarbon oil that is suspended from a coverslip, which is, in turn, fixed in position over a humid chamber. In addition to providing gas exchange and preventing dehydration, this arrangement takes advantage of the buoyancy of embryos in halocarbon oil to prevent them from drifting out of position during timelapse acquisition. This video describes in detail how to collect and prepare Drosophila embryos for live imaging using the hanging drop protocol. This protocol is suitable for imaging dechorionated embryos using stereomicroscopy or any upright compound fluorescence microscope.

Kilovoltage cone-beam CT: Comparative dose and image quality evaluations in partial and full-angle scan protocols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Sangroh; Yoo, Sua; Yin Fangfang

2010-07-15

Purpose: To assess imaging dose of partial and full-angle kilovoltage CBCT scan protocols and to evaluate image quality for each protocol. Methods: The authors obtained the CT dose index (CTDI) of the kilovoltage CBCT protocols in an on-board imager by ion chamber (IC) measurements and Monte Carlo (MC) simulations. A total of six new CBCT scan protocols were evaluated: Standard-dose head (100 kVp, 151 mA s, partial-angle), low-dose head (100 kVp, 75 mA s, partial-angle), high-quality head (100 kVp, 754 mA s, partial-angle), pelvis (125 kVp, 706 mA s, full-angle), pelvis spotlight (125 kVp, 752 mA s, partial-angle), and low-dosemore » thorax (110 kVp, 271 mA s, full-angle). Using the point dose method, various CTDI values were calculated by (1) the conventional weighted CTDI (CTDI{sub w}) calculation and (2) Bakalyar's method (CTDI{sub wb}). The MC simulations were performed to obtain the CTDI{sub w} and CTDI{sub wb}, as well as from (3) central slice averaging (CTDI{sub 2D}) and (4) volume averaging (CTDI{sub 3D}) techniques. The CTDI values of the new protocols were compared to those of the old protocols (full-angle CBCT protocols). Image quality of the new protocols was evaluated following the CBCT image quality assurance (QA) protocol [S. Yoo et al., ''A quality assurance program for the on-board imager registered ,'' Med. Phys. 33(11), 4431-4447 (2006)] testing Hounsfield unit (HU) linearity, spatial linearity/resolution, contrast resolution, and HU uniformity. Results: The CTDI{sub w} were found as 6.0, 3.2, 29.0, 25.4, 23.8, and 7.7 mGy for the new protocols, respectively. The CTDI{sub w} and CTDI{sub wb} differed within +3% between IC measurements and MC simulations. Method (2) results were within {+-}12% of method (1). In MC simulations, the CTDI{sub w} and CTDI{sub wb} were comparable to the CTDI{sub 2D} and CTDI{sub 3D} with the differences ranging from -4.3% to 20.6%. The CTDI{sub 3D} were smallest among all the CTDI values. CTDI{sub w} of the new protocols were found as {approx}14 times lower for standard head scan and 1.8 times lower for standard body scan than the old protocols, respectively. In the image quality QA tests, all the protocols except low-dose head and low-dose thorax protocols were within the tolerance in the HU verification test. The HU value for the two protocols was always higher than the nominal value. All the protocols passed the spatial linearity/resolution and HU uniformity tests. In the contrast resolution test, only high-quality head and pelvis scan protocols were within the tolerance. In addition, crescent effect was found in the partial-angle scan protocols. Conclusions: The authors found that CTDI{sub w} of the new CBCT protocols has been significantly reduced compared to the old protocols with acceptable image quality. The CTDI{sub w} values in the point dose method were close to the volume averaging method within 9%-21% for all the CBCT scan protocols. The Bakalyar's method produced more accurate dose estimation within 14%. The HU inaccuracy from low-dose head and low-dose thorax protocols can render incorrect dose results in the treatment planning system. When high soft-tissue contrast data are desired, high-quality head or pelvis scan protocol is recommended depending on the imaging area. The point dose method can be applicable to estimate CBCT dose with reasonable accuracy in the clinical environment.« less

OARSI Clinical Trials Recommendations for Hip Imaging in Osteoarthritis

PubMed Central

Gold, Garry E.; Cicuttini, Flavia; Crema, Michel D.; Eckstein, Felix; Guermazi, Ali; Kijowski, Richard; Link, Thomas M.; Maheu, Emmanuel; Martel-Pelletier, Johanne; Miller, Colin G.; Pelletier, Jean-Pierre; Peterfy, Charles G.; Potter, Hollis G.; Roemer, Frank W.; Hunter, David. J

2015-01-01

Imaging of hip in osteoarthritis (OA) has seen considerable progress in the past decade, with the introduction of new techniques that may be more sensitive to structural disease changes. The purpose of this expert opinion, consensus driven recommendation is to provide detail on how to apply hip imaging in disease modifying clinical trials. It includes information on acquisition methods/ techniques (including guidance on positioning for radiography, sequence/protocol recommendations/ hardware for MRI); commonly encountered problems (including positioning, hardware and coil failures, artifacts associated with various MRI sequences); quality assurance/ control procedures; measurement methods; measurement performance (reliability, responsiveness, and validity); recommendations for trials; and research recommendations. PMID:25952344

Paperless protocoling of CT and MRI requests at an outpatient imaging center.

PubMed

Bassignani, Matthew J; Dierolf, David A; Roberts, David L; Lee, Steven

2010-04-01

We created our imaging center (IC) to move outpatient imaging from our busy inpatient imaging suite off-site to a location that is more inviting to ambulatory patients. Nevertheless, patients scanned at our IC still represent the depth and breadth of illness complexity seen with our tertiary care population. Thus, we protocol exams on an individualized basis to ensure that the referring clinician's question is fully answered by the exam performed. Previously, paper based protocoling was a laborious process for all those involved where the IC business office would fax the requests to various reading rooms for protocoling by the subspecialist radiologists who are 3 miles away at the main hospital. Once protocoled, reading room coordinators would fax back the protocoled request to the IC technical area in preparation for the next day's scheduled exams. At any breakdown in this process (e.g., lost paperwork), patient exams were delayed and clinicians and patients became upset. To improve this process, we developed a paper free process whereby protocoling is accomplished through scanning of exam requests into our PACS. Using the common worklist functionality found in most PACS, we created "protocoling worklists" that contain these scanned documents. Radiologists protocol these studies in the PACS worklist (with the added benefit of having all imaging and report data available), and subsequently, the technologists can see and act on the protocols they find in PACS. This process has significantly decreased interruptions in our busy reading rooms and decreased rework of IC staff.

Optimizing radiation exposure in screening of body packing: image quality and diagnostic acceptability of an 80 kVp protocol with automated tube current modulation.

PubMed

Aissa, Joel; Boos, Johannes; Rubbert, Christian; Caspers, Julian; Schleich, Christoph; Thomas, Christoph; Kröpil, Patric; Antoch, Gerald; Miese, Falk

2017-06-01

The aim of this study was to evaluate the objective and subjective image quality of a novel computed tomography (CT) protocol with reduced radiation dose for body packing with 80 kVp and automated tube current modulation (ATCM) compared to a standard body packing CT protocol. 80 individuals who were examined between March 2012 and July 2015 in suspicion of ingested drug packets were retrospectively included in this study. Thirty-one CT examinations were performed using ATCM and a fixed tube voltage of 80 kVp (group A). Forty-nine CT examinations were performed using a standard protocol with a tube voltage of 120 kVp and a fixed tube current time product of 40 mAs (group B). Subjective and objective image quality and visibility of drug packets were assessed. Radiation exposure of both protocols was compared. Contrast-to-noise ratio (group A: 0.56 ± 0.36; group B: 1.13 ± 0.91) and Signal-to-noise ratio (group A: 3.69 ± 0.98; group B: 7.08 ± 2.67) were significantly lower for group A compared to group B (p < 0.001). Subjectively, image quality was decreased for group A compared to group B (2.5 ± 0.8 vs. 1.2 ± 0.4; p < 0.001). Attenuation of body packets was higher with the new protocol (group A: 362.2 ± 70.3 Hounsfield Units (HU); group B: 210.6 ± 60.2 HU; p = 0.005). Volumetric Computed Tomography Dose Index (CTDIvol) and Dose Length Product (DLP) were significantly lower in group A (CTDIvol 2.2 ± 0.9 mGy, DLP 105.7 ± 52.3 mGycm) as compared to group B (CTDIvol 2.7 ± 0.1 mGy, DLP 126.0 ± 9.7 mGycm, p = 0.002 and p = 0.01). The novel 80 kVp CT protocol with ATCM leads to a significant dose reduction compared to a standard CT body packing protocol. The novel protocol led to a diagnostic image quality and cocaine body packets were reliably detected due to the high attenuation.

Database integration of protocol-specific neurological imaging datasets

PubMed Central

Pacurar, Emil E.; Sethi, Sean K.; Habib, Charbel; Laze, Marius O.; Martis-Laze, Rachel; Haacke, E. Mark

2016-01-01

For many years now, Magnetic Resonance Innovations (MR Innovations), a magnetic resonance imaging (MRI) software development, technology, and research company, has been aggregating a multitude of MRI data from different scanning sites through its collaborations and research contracts. The majority of the data has adhered to neuroimaging protocols developed by our group which has helped ensure its quality and consistency. The protocols involved include the study of: traumatic brain injury, extracranial venous imaging for multiple sclerosis and Parkinson's disease, and stroke. The database has proven invaluable in helping to establish disease biomarkers, validate findings across multiple data sets, develop and refine signal processing algorithms, and establish both public and private research collaborations. Myriad Masters and PhD dissertations have been possible thanks to the availability of this database. As an example of a project that cuts across diseases, we have used the data and specialized software to develop new guidelines for detecting cerebral microbleeds. Ultimately, the database has been vital in our ability to provide tools and information for researchers and radiologists in diagnosing their patients, and we encourage collaborations and welcome sharing of similar data in this database. PMID:25959660

Global Picture Archiving and Communication Systems (GPACS): An Overview

DTIC Science & Technology

1994-04-01

a separate entity in most hospitals because of the integration problems that exilb. Eventually these systems should be connected so they appear to the...extremely important to efficient image data transfer include the protocol being used between the two transferring entities . Image data is currently...images, sound or video. The actual database consists of a collection of persistent data that is used by an application system of some entity , in this

SU-E-I-68: Practical Considerations On Implementation of the Image Gently Pediatric CT Protocols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, J; Adams, C; Lumby, C

Purpose: One limitation associated with the Image Gently pediatric CT protocols is practical implementation of the recommended manual techniques. Inconsistency as a result of different practice is a possibility among technologist. An additional concern is the added risk of data error that would result in over or underexposure. The Automatic Exposure Control (AEC) features automatically reduce radiation for children. However, they do not work efficiently for the patients of very small size and relative large size. This study aims to implement the Image Gently pediatric CT protocols in the practical setting while maintaining the use of AEC features for pediatricmore » patients of varying size. Methods: Anthropomorphological abdomen phantoms were scanned in a CT scanner using the Image Gently pediatric protocols, the AEC technique with a fixed adult baseline, and automatic protocols with various baselines. The baselines were adjusted corresponding to patient age, weight and posterioranterior thickness to match the Image Gently pediatric CT manual techniques. CTDIvol was recorded for each examination. Image noise was measured and recorded for image quality comparison. Clinical images were evaluated by pediatric radiologists. Results: By adjusting vendor default baselines used in the automatic techniques, radiation dose and image quality can match those of the Image Gently manual techniques. In practice, this can be achieved by dividing pediatric patients into three major groups for technologist reference: infant, small child, and large child. Further division can be done but will increase the number of CT protocols. For each group, AEC can efficiently adjust acquisition techniques for children. This implementation significantly overcomes the limitation of the Image Gently manual techniques. Conclusion: Considering the effectiveness in clinical practice, Image Gently Pediatric CT protocols can be implemented in accordance with AEC techniques, with adjusted baselines, to achieve the goal of providing the most appropriate radiation dose for pediatric patients of varying sizes.« less

Magnetic resonance cinematography of the fingers: a 3.0 Tesla feasibility study with comparison of incremental and continuous dynamic protocols.

PubMed

Bayer, Thomas; Adler, Werner; Janka, Rolf; Uder, Michael; Roemer, Frank

2017-12-01

To study the feasibility of magnetic resonance cinematography of the fingers (MRCF) with comparison of image quality of different protocols for depicting the finger anatomy during motion. MRCF was performed during a full flexion and extension movement in 14 healthy volunteers using a finger-gating device. Three real-time sequences (frame rates 17-59 images/min) and one proton density (PD) sequence (3 images/min) were acquired during incremental and continuous motion. Analyses were performed independently by three readers. Qualitative image analysis included Likert-scale grading from 0 (useless) to 5 (excellent) and specific visual analog scale (VAS) grading from 0 (insufficient) to 100 (excellent). Signal-to-noise calculation was performed. Overall percentage agreement and mean absolute disagreement were calculated. Within the real-time sequences a high frame-rate true fast imaging with steady-state free precession (TRUFI) yielded the best image quality with Likert and overall VAS scores of 3.0 ± 0.2 and 60.4 ± 25.3, respectively. The best sequence regarding image quality was an incremental PD with mean values of 4.8 ± 0.2 and 91.2 ± 9.4, respectively. Overall percentage agreement and mean absolute disagreement were 47.9 and 0.7, respectively. No statistically significant SNR differences were found between continuous and incremental motion for the real-time protocols. MRCF is feasible with appropriate image quality during continuous motion using a finger-gating device. Almost perfect image quality is achievable with incremental PD imaging, which represents a compromise for MRCF with the drawback of prolonged scanning time.

Providing Internet Access to High-Resolution Mars Images

NASA Technical Reports Server (NTRS)

Plesea, Lucian

2008-01-01

The OnMars server is a computer program that provides Internet access to high-resolution Mars images, maps, and elevation data, all suitable for use in geographical information system (GIS) software for generating images, maps, and computational models of Mars. The OnMars server is an implementation of the Open Geospatial Consortium (OGC) Web Map Service (WMS) server. Unlike other Mars Internet map servers that provide Martian data using an Earth coordinate system, the OnMars WMS server supports encoding of data in Mars-specific coordinate systems. The OnMars server offers access to most of the available high-resolution Martian image and elevation data, including an 8-meter-per-pixel uncontrolled mosaic of most of the Mars Global Surveyor (MGS) Mars Observer Camera Narrow Angle (MOCNA) image collection, which is not available elsewhere. This server can generate image and map files in the tagged image file format (TIFF), Joint Photographic Experts Group (JPEG), 8- or 16-bit Portable Network Graphics (PNG), or Keyhole Markup Language (KML) format. Image control is provided by use of the OGC Style Layer Descriptor (SLD) protocol. The OnMars server also implements tiled WMS protocol and super-overlay KML for high-performance client application programs.

A protocol for bladder cancer screening and medical surveillance among high-risk groups: The Drake Health Registry experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsh, G.M.; Callahan, C.; Pavlock, D.

In 1986, the Drake Health Registry Study initiated bladder cancer screening for 366 persons at high risk because of occupational exposure to beta-naphthylamine. The Drake Health Registry Study screening protocol consists of urinalysis, Papanicolaou cytology, and quantitative fluorescence image analysis. A positive screening test qualifies participants for a full diagnostic evaluation. The screening protocol has been modified during the first 3 years of the program's existence to address unexpected patterns of test results and to incorporate advances in screening technology. The current protocol, which has a two-tiered screening schedule, has been utilized successfully for 15 months. Of the 26 positivemore » results to date most have been based on abnormal Papanicolaou cytology and/or quantitative fluorescence image analysis. Bladder abnormalities were cited among most of the 18 study members who underwent diagnostic evaluation, including chronic cystitis, inflammation, hyperplasia, and dysplasia. We conclude that the screening program is detecting very early changes in a relatively young cohort and that these persons must be monitored over a number of years to ensure adequate medical surveillance.« less

Position paper: Rationale for the treatment of Wilms tumour in the UMBRELLA SIOP-RTSG 2016 protocol.

PubMed

van den Heuvel-Eibrink, Marry M; Hol, Janna A; Pritchard-Jones, Kathy; van Tinteren, Harm; Furtwängler, Rhoikos; Verschuur, Arnauld C; Vujanic, Gordan M; Leuschner, Ivo; Brok, Jesper; Rübe, Christian; Smets, Anne M; Janssens, Geert O; Godzinski, Jan; Ramírez-Villar, Gema L; de Camargo, Beatriz; Segers, Heidi; Collini, Paola; Gessler, Manfred; Bergeron, Christophe; Spreafico, Filippo; Graf, Norbert

2017-12-01

The Renal Tumour Study Group of the International Society of Paediatric Oncology (SIOP-RTSG) has developed a new protocol for the diagnosis and treatment of childhood renal tumours, the UMBRELLA SIOP-RTSG 2016 (the UMBRELLA protocol), to continue international collaboration in the treatment of childhood renal tumours. This protocol will support integrated biomarker and imaging research, focussing on assessing the independent prognostic value of genomic changes within the tumour and the volume of the blastemal component that survives preoperative chemotherapy. Treatment guidelines for Wilms tumours in the UMBRELLA protocol include recommendations for localized, metastatic, and bilateral disease, for all age groups, and for relapsed disease. These recommendations have been established by a multidisciplinary panel of leading experts on renal tumours within the SIOP-RTSG. The UMBRELLA protocol should promote international collaboration and research and serve as the SIOP-RTSG best available treatment standard.

SU-D-BRA-07: A Phantom Study to Assess the Variability in Radiomics Features Extracted From Cone-Beam CT Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fave, X; Fried, D; UT Health Science Center Graduate School of Biomedical Sciences, Houston, TX

2015-06-15

Purpose: Several studies have demonstrated the prognostic potential for texture features extracted from CT images of non-small cell lung cancer (NSCLC) patients. The purpose of this study was to determine if these features could be extracted with high reproducibility from cone-beam CT (CBCT) images in order for features to be easily tracked throughout a patient’s treatment. Methods: Two materials in a radiomics phantom, designed to approximate NSCLC tumor texture, were used to assess the reproducibility of 26 features. This phantom was imaged on 9 CBCT scanners, including Elekta and Varian machines. Thoracic and head imaging protocols were acquired on eachmore » machine. CBCT images from 27 NSCLC patients imaged using the thoracic protocol on Varian machines were obtained for comparison. The variance for each texture measured from these patients was compared to the variance in phantom values for different manufacturer/protocol subsets. Levene’s test was used to identify features which had a significantly smaller variance in the phantom scans versus the patient data. Results: Approximately half of the features (13/26 for material1 and 15/26 for material2) had a significantly smaller variance (p<0.05) between Varian thoracic scans of the phantom compared to patient scans. Many of these same features remained significant for the head scans on Varian (12/26 and 8/26). However, when thoracic scans from Elekta and Varian were combined, only a few features were still significant (4/26 and 5/26). Three features (skewness, coarsely filtered mean and standard deviation) were significant in almost all manufacturer/protocol subsets. Conclusion: Texture features extracted from CBCT images of a radiomics phantom are reproducible and show significantly less variation than the same features measured from patient images when images from the same manufacturer or with similar parameters are used. Reproducibility between CBCT scanners may be high enough to allow the extraction of meaningful texture values for patients. This project was funded in part by the Cancer Prevention Research Institute of Texas (CPRIT). Xenia Fave is a recipient of the American Association of Physicists in Medicine Graduate Fellowship.« less

CAIPIRINHA accelerated SPACE enables 10-min isotropic 3D TSE MRI of the ankle for optimized visualization of curved and oblique ligaments and tendons.

PubMed

Kalia, Vivek; Fritz, Benjamin; Johnson, Rory; Gilson, Wesley D; Raithel, Esther; Fritz, Jan

2017-09-01

To test the hypothesis that a fourfold CAIPIRINHA accelerated, 10-min, high-resolution, isotropic 3D TSE MRI prototype protocol of the ankle derives equal or better quality than a 20-min 2D TSE standard protocol. Following internal review board approval and informed consent, 3-Tesla MRI of the ankle was obtained in 24 asymptomatic subjects including 10-min 3D CAIPIRINHA SPACE TSE prototype and 20-min 2D TSE standard protocols. Outcome variables included image quality and visibility of anatomical structures using 5-point Likert scales. Non-parametric statistical testing was used. P values ≤0.001 were considered significant. Edge sharpness, contrast resolution, uniformity, noise, fat suppression and magic angle effects were without statistical difference on 2D and 3D TSE images (p > 0.035). Fluid was mildly brighter on intermediate-weighted 2D images (p < 0.001), whereas 3D images had substantially less partial volume, chemical shift and no pulsatile-flow artifacts (p < 0.001). Oblique and curved planar 3D images resulted in mildly-to-substantially improved visualization of joints, spring, bifurcate, syndesmotic, collateral and sinus tarsi ligaments, and tendons (p < 0.001, respectively). 3D TSE MRI with CAIPIRINHA acceleration enables high-spatial resolution oblique and curved planar MRI of the ankle and visualization of ligaments, tendons and joints equally well or better than a more time-consuming anisotropic 2D TSE MRI. • High-resolution 3D TSE MRI improves visualization of ankle structures. • Limitations of current 3D TSE MRI include long scan times. • 3D CAIPIRINHA SPACE allows now a fourfold-accelerated data acquisition. • 3D CAIPIRINHA SPACE enables high-spatial-resolution ankle MRI within 10 min. • 10-min 3D CAIPIRINHA SPACE produces equal-or-better quality than 20-min 2D TSE.

Experience with Delay-Tolerant Networking from Orbit

NASA Technical Reports Server (NTRS)

Ivancic, W.; Eddy, W. M.; Stewart, D.; Wood, L.; Northam, J.; Jackson, C.

2010-01-01

We describe the first use from space of the Bundle Protocol for Delay-Tolerant Networking (DTN) and lessons learned from experiments made and experience gained with this protocol. The Disaster Monitoring Constellation (DMC), constructed by Surrey Satellite Technology Ltd (SSTL), is a multiple-satellite Earth-imaging low-Earth-orbit sensor network in which recorded image swaths are stored onboard each satellite and later downloaded from the satellite payloads to a ground station. Store-and-forward of images with capture and later download gives each satellite the characteristics of a node in a disruption-tolerant network. Originally developed for the Interplanetary Internet, DTNs are now under investigation in an Internet Research Task Force (IRTF) DTN research group (RG), which has developed a bundle architecture and protocol. The DMC is technically advanced in its adoption of the Internet Protocol (IP) for its imaging payloads and for satellite command and control, based around reuse of commercial networking and link protocols. These satellites use of IP has enabled earlier experiments with the Cisco router in Low Earth Orbit (CLEO) onboard the constellation s UK-DMC satellite. Earth images are downloaded from the satellites using a custom IP-based high-speed transfer protocol developed by SSTL, Saratoga, which tolerates unusual link environments. Saratoga has been documented in the Internet Engineering Task Force (IETF) for wider adoption. We experiment with the use of DTNRG bundle concepts onboard the UK-DMC satellite, by examining how Saratoga can be used as a DTN convergence layer to carry the DTNRG Bundle Protocol, so that sensor images can be delivered to ground stations and beyond as bundles. Our practical experience with the first successful use of the DTNRG Bundle Protocol in a space environment gives us insights into the design of the Bundle Protocol and enables us to identify issues that must be addressed before wider deployment of the Bundle Protocol. Published in 2010 by John Wiley & Sons, Ltd. KEY WORDS: Internet; UK-DMC; satellite; Delay-Tolerant Networking (DTN); Bundle Protocol

An anthropomorphic phantom for quantitative evaluation of breast MRI.

PubMed

Freed, Melanie; de Zwart, Jacco A; Loud, Jennifer T; El Khouli, Riham H; Myers, Kyle J; Greene, Mark H; Duyn, Jeff H; Badano, Aldo

2011-02-01

In this study, the authors aim to develop a physical, tissue-mimicking phantom for quantitative evaluation of breast MRI protocols. The objective of this phantom is to address the need for improved standardization in breast MRI and provide a platform for evaluating the influence of image protocol parameters on lesion detection and discrimination. Quantitative comparisons between patient and phantom image properties are presented. The phantom is constructed using a mixture of lard and egg whites, resulting in a random structure with separate adipose- and glandular-mimicking components. T1 and T2 relaxation times of the lard and egg components of the phantom were estimated at 1.5 T from inversion recovery and spin-echo scans, respectively, using maximum-likelihood methods. The image structure was examined quantitatively by calculating and comparing spatial covariance matrices of phantom and patient images. A static, enhancing lesion was introduced by creating a hollow mold with stereolithography and filling it with a gadolinium-doped water solution. Measured phantom relaxation values fall within 2 standard errors of human values from the literature and are reasonably stable over 9 months of testing. Comparison of the covariance matrices of phantom and patient data demonstrates that the phantom and patient data have similar image structure. Their covariance matrices are the same to within error bars in the anterior-posterior direction and to within about two error bars in the right-left direction. The signal from the phantom's adipose-mimicking material can be suppressed using active fat-suppression protocols. A static, enhancing lesion can also be included with the ability to change morphology and contrast agent concentration. The authors have constructed a phantom and demonstrated its ability to mimic human breast images in terms of key physical properties that are relevant to breast MRI. This phantom provides a platform for the optimization and standardization of breast MRI imaging protocols for lesion detection and characterization.

Single-cell in vivo imaging of adult neural stem cells in the zebrafish telencephalon.

PubMed

Barbosa, Joana S; Di Giaimo, Rossella; Götz, Magdalena; Ninkovic, Jovica

2016-08-01

Adult neural stem cells (aNSCs) in zebrafish produce mature neurons throughout their entire life span in both the intact and regenerating brain. An understanding of the behavior of aNSCs in their intact niche and during regeneration in vivo should facilitate the identification of the molecular mechanisms controlling regeneration-specific cellular events. A greater understanding of the process in regeneration-competent species may enable regeneration to be achieved in regeneration-incompetent species, including humans. Here we describe a protocol for labeling and repetitive imaging of aNSCs in vivo. We label single aNSCs, allowing nonambiguous re-identification of single cells in repetitive imaging sessions using electroporation of a red-reporter plasmid in Tg(gfap:GFP)mi2001 transgenic fish expressing GFP in aNSCs. We image using two-photon microscopy through the thinned skull of anesthetized and immobilized fish. Our protocol allows imaging every 2 d for a period of up to 1 month. This methodology allowed the visualization of aNSC behavior in vivo in their natural niche, in contrast to previously available technologies, which rely on the imaging of either dissociated cells or tissue slices. We used this protocol to follow the mode of aNSC division, fate changes and cell death in both the intact and injured zebrafish telencephalon. This experimental setup can be widely used, with minimal prior experience, to assess key factors for processes that modulate aNSC behavior. A typical experiment with data analysis takes up to 1.5 months.

Multi-site Study of Diffusion Metric Variability: Characterizing the Effects of Site, Vendor, Field Strength, and Echo Time using the Histogram Distance.

PubMed

Helmer, K G; Chou, M-C; Preciado, R I; Gimi, B; Rollins, N K; Song, A; Turner, J; Mori, S

2016-02-27

MRI-based multi-site trials now routinely include some form of diffusion-weighted imaging (DWI) in their protocol. These studies can include data originating from scanners built by different vendors, each with their own set of unique protocol restrictions, including restrictions on the number of available gradient directions, whether an externally-generated list of gradient directions can be used, and restrictions on the echo time (TE). One challenge of multi-site studies is to create a common imaging protocol that will result in a reliable and accurate set of diffusion metrics. The present study describes the effect of site, scanner vendor, field strength, and TE on two common metrics: the first moment of the diffusion tensor field (mean diffusivity, MD), and the fractional anisotropy (FA). We have shown in earlier work that ROI metrics and the mean of MD and FA histograms are not sufficiently sensitive for use in site characterization. Here we use the distance between whole brain histograms of FA and MD to investigate within- and between-site effects. We concluded that the variability of DTI metrics due to site, vendor, field strength, and echo time could influence the results in multi-center trials and that histogram distance is sensitive metrics for each of these variables.

Electron microscopy using the genetically encoded APEX2 tag in cultured mammalian cells

PubMed Central

Martell, Jeffrey D; Deerinck, Thomas J; Lam, Stephanie S; Ellisman, Mark H; Ting, Alice Y

2018-01-01

Electron microscopy (EM) is the premiere technique for high-resolution imaging of cellular ultrastructure. Unambiguous identification of specific proteins or cellular compartments in electron micrographs, however, remains challenging because of difficulties in delivering electron-dense contrast agents to specific subcellular targets within intact cells. We recently reported enhanced ascorbate peroxidase 2 (APEX2) as a broadly applicable genetic tag that generates EM contrast on a specific protein or subcellular compartment of interest. This protocol provides guidelines for designing and validating APEX2 fusion constructs, along with detailed instructions for cell culture, transfection, fixation, heavy-metal staining, embedding in resin, and EM imaging. Although this protocol focuses on EM in cultured mammalian cells, APEX2 is applicable to many cell types and contexts, including intact tissues and organisms, and is useful for numerous applications beyond EM, including live-cell proteomic mapping. This protocol, which describes procedures for sample preparation from cell monolayers and cell pellets, can be completed in 10 d, including time for APEX2 fusion construct validation, cell growth, and solidification of embedding resins. Notably, the only additional steps required relative to a standard EM sample preparation are cell transfection and a 2- to 45-min staining period with 3,3′-diaminobenzidine (DAB) and hydrogen peroxide (H2O2). PMID:28796234

Visualization of the internal globus pallidus: sequence and orientation for deep brain stimulation using a standard installation protocol at 3.0 Tesla.

PubMed

Nölte, Ingo S; Gerigk, Lars; Al-Zghloul, Mansour; Groden, Christoph; Kerl, Hans U

2012-03-01

Deep-brain stimulation (DBS) of the internal globus pallidus (GPi) has shown remarkable therapeutic benefits for treatment-resistant neurological disorders including dystonia and Parkinson's disease (PD). The success of the DBS is critically dependent on the reliable visualization of the GPi. The aim of the study was to evaluate promising 3.0 Tesla magnetic resonance imaging (MRI) methods for pre-stereotactic visualization of the GPi using a standard installation protocol. MRI at 3.0 T of nine healthy individuals and of one patient with PD was acquired (FLAIR, T1-MPRAGE, T2-SPACE, T2*-FLASH2D, susceptibility-weighted imaging mapping (SWI)). Image quality and visualization of the GPi for each sequence were assessed by two neuroradiologists independently using a 6-point scale. Axial, coronal, and sagittal planes of the T2*-FLASH2D images were compared. Inter-rater reliability, contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) for the GPi were determined. For illustration, axial T2*-FLASH2D images were fused with a section schema of the Schaltenbrand-Wahren stereotactic atlas. The GPi was best and reliably visualized in axial and to a lesser degree on coronal T2*-FLASH2D images. No major artifacts in the GPi were observed in any of the sequences. SWI offered a significantly higher CNR for the GPi compared to standard T2-weighted imaging using the standard parameters. The fusion of the axial T2*-FLASH2D images and the atlas projected the GPi clearly in the boundaries of the section schema. Using a standard installation protocol at 3.0 T T2*-FLASH2D imaging (particularly axial view) provides optimal and reliable delineation of the GPi.

A cross-platform survey of CT image quality and dose from routine abdomen protocols and a method to systematically standardize image quality

PubMed Central

Favazza, Christopher P.; Duan, Xinhui; Zhang, Yi; Yu, Lifeng; Leng, Shuai; Kofler, James M.; Bruesewitz, Michael R.; McCollough, Cynthia H.

2015-01-01

Through this investigation we developed a methodology to evaluate and standardize CT image quality from routine abdomen protocols across different manufacturers and models. The influence of manufacturer-specific automated exposure control systems on image quality was directly assessed to standardize performance across a range of patient sizes. We evaluated 16 CT scanners across our health system, including Siemens, GE, and Toshiba models. Using each practice’s routine abdomen protocol, we measured spatial resolution, image noise, and scanner radiation output (CTDIvol). Axial and in-plane spatial resolutions were assessed through slice sensitivity profile (SSP) and modulation transfer function (MTF) measurements, respectively. Image noise and CTDIvol values were obtained for three different phantom sizes. SSP measurements demonstrated a bimodal distribution in slice widths: an average of 6.2 ± 0.2 mm using GE’s “Plus” mode reconstruction setting and 5.0 ± 0.1 mm for all other scanners. MTF curves were similar for all scanners. Average spatial frequencies at 50%, 10%, and 2% MTF values were 3.24 ± 0.37, 6.20 ± 0.34, and 7.84 ± 0.70 lp/cm, respectively. For all phantom sizes, image noise and CTDIvol varied considerably: 6.5–13.3 HU (noise) and 4.8–13.3 mGy (CTDIvol) for the smallest phantom; 9.1–18.4 HU and 9.3–28.8 mGy for the medium phantom; and 7.8–23.4 HU and 16.0–48.1 mGy for the largest phantom. Using these measurements and benchmark SSP, MTF, and image noise targets, CT image quality can be standardized across a range of patient sizes. PMID:26459751

Dependency of image quality on acquisition protocol and image processing in chest tomosynthesis-a visual grading study based on clinical data.

PubMed

Jadidi, Masoud; Båth, Magnus; Nyrén, Sven

2018-04-09

To compare the quality of images obtained with two different protocols with different acquisition time and the influence from image post processing in a chest digital tomosynthesis (DTS) system. 20 patients with suspected lung cancer were imaged with a chest X-ray equipment with tomosynthesis option. Two examination protocols with different acquisition times (6.3 and 12 s) were performed on each patient. Both protocols were presented with two different image post-processing (standard DTS processing and more advanced processing optimised for chest radiography). Thus, 4 series from each patient, altogether 80 series, were presented anonymously and in a random order. Five observers rated the quality of the reconstructed section images according to predefined quality criteria in three different classes. Visual grading characteristics (VGC) was used to analyse the data and the area under the VGC curve (AUC VGC ) was used as figure-of-merit. The 12 s protocol and the standard DTS processing were used as references in the analyses. The protocol with 6.3 s acquisition time had a statistically significant advantage over the vendor-recommended protocol with 12 s acquisition time for the classes of criteria, Demarcation (AUC VGC = 0.56, p = 0.009) and Disturbance (AUC VGC = 0.58, p < 0.001). A similar value of AUC VGC was found also for the class Structure (definition of bone structures in the spine) (0.56) but it could not be statistically separated from 0.5 (p = 0.21). For the image processing, the VGC analysis showed a small but statistically significant advantage for the standard DTS processing over the more advanced processing for the classes of criteria Demarcation (AUC VGC = 0.45, p = 0.017) and Disturbance (AUC VGC = 0.43, p = 0.005). A similar value of AUC VGC was found also for the class Structure (0.46), but it could not be statistically separated from 0.5 (p = 0.31). The study indicates that the protocol with 6.3 s acquisition time yields slightly better image quality than the vender-recommended protocol with acquisition time 12 s for several anatomical structures. Furthermore, the standard gradation processing  (the vendor-recommended post-processing for DTS), yields to some extent advantage over the gradation processing/multiobjective frequency processing/flexible noise control processing in terms of image quality for all classes of criteria. Advances in knowledge: The study proves that the image quality may be strongly affected by the selection of DTS protocol and that the vendor-recommended protocol may not always be the optimal choice.

Dual tracer imaging of SPECT and PET probes in living mice using a sequential protocol

PubMed Central

Chapman, Sarah E; Diener, Justin M; Sasser, Todd A; Correcher, Carlos; González, Antonio J; Avermaete, Tony Van; Leevy, W Matthew

2012-01-01

Over the past 20 years, multimodal imaging strategies have motivated the fusion of Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) scans with an X-ray computed tomography (CT) image to provide anatomical information, as well as a framework with which molecular and functional images may be co-registered. Recently, pre-clinical nuclear imaging technology has evolved to capture multiple SPECT or multiple PET tracers to further enhance the information content gathered within an imaging experiment. However, the use of SPECT and PET probes together, in the same animal, has remained a challenge. Here we describe a straightforward method using an integrated trimodal imaging system and a sequential dosing/acquisition protocol to achieve dual tracer imaging with 99mTc and 18F isotopes, along with anatomical CT, on an individual specimen. Dosing and imaging is completed so that minimal animal manipulations are required, full trimodal fusion is conserved, and tracer crosstalk including down-scatter of the PET tracer in SPECT mode is avoided. This technique will enhance the ability of preclinical researchers to detect multiple disease targets and perform functional, molecular, and anatomical imaging on individual specimens to increase the information content gathered within longitudinal in vivo studies. PMID:23145357

High-resolution Episcopic Microscopy (HREM) - Simple and Robust Protocols for Processing and Visualizing Organic Materials

PubMed Central

Geyer, Stefan H.; Maurer-Gesek, Barbara; Reissig, Lukas F.; Weninger, Wolfgang J.

2017-01-01

We provide simple protocols for generating digital volume data with the high-resolution episcopic microscopy (HREM) method. HREM is capable of imaging organic materials with volumes up to 5 x 5 x 7 mm3 in typical numeric resolutions between 1 x 1 x 1 and 5 x 5 x 5 µm3. Specimens are embedded in methacrylate resin and sectioned on a microtome. After each section an image of the block surface is captured with a digital video camera that sits on the phototube connected to the compound microscope head. The optical axis passes through a green fluorescent protein (GFP) filter cube and is aligned with a position, at which the bock holder arm comes to rest after each section. In this way, a series of inherently aligned digital images, displaying subsequent block surfaces are produced. Loading such an image series in three-dimensional (3D) visualization software facilitates the immediate conversion to digital volume data, which permit virtual sectioning in various orthogonal and oblique planes and the creation of volume and surface rendered computer models. We present three simple, tissue specific protocols for processing various groups of organic specimens, including mouse, chick, quail, frog and zebra fish embryos, human biopsy material, uncoated paper and skin replacement material. PMID:28715372

High-resolution Episcopic Microscopy (HREM) - Simple and Robust Protocols for Processing and Visualizing Organic Materials.

PubMed

Geyer, Stefan H; Maurer-Gesek, Barbara; Reissig, Lukas F; Weninger, Wolfgang J

2017-07-07

We provide simple protocols for generating digital volume data with the high-resolution episcopic microscopy (HREM) method. HREM is capable of imaging organic materials with volumes up to 5 x 5 x 7 mm 3 in typical numeric resolutions between 1 x 1 x 1 and 5 x 5 x 5 µm 3 . Specimens are embedded in methacrylate resin and sectioned on a microtome. After each section an image of the block surface is captured with a digital video camera that sits on the phototube connected to the compound microscope head. The optical axis passes through a green fluorescent protein (GFP) filter cube and is aligned with a position, at which the bock holder arm comes to rest after each section. In this way, a series of inherently aligned digital images, displaying subsequent block surfaces are produced. Loading such an image series in three-dimensional (3D) visualization software facilitates the immediate conversion to digital volume data, which permit virtual sectioning in various orthogonal and oblique planes and the creation of volume and surface rendered computer models. We present three simple, tissue specific protocols for processing various groups of organic specimens, including mouse, chick, quail, frog and zebra fish embryos, human biopsy material, uncoated paper and skin replacement material.

A highly sensitive protocol for microscopy of alkyne lipids and fluorescently tagged or immunostained proteins[S

PubMed Central

Gaebler, Anne; Penno, Anke; Kuerschner, Lars; Thiele, Christoph

2016-01-01

The demand to study the cellular localization of specific lipids has led to recent advances in lipid probes and microscopy. Alkyne lipids bear a small, noninterfering tag and can be detected upon click reaction with an azide-coupled reporter. Fluorescent alkyne lipid imaging crucially depends on appropriate azide reporters and labeling protocols that allow for an efficient click reaction and therefore a sensitive detection. We synthesized several azide reporters with different spacer components and tested their suitability for alkyne lipid imaging in fixed cells. The implementation of a copper-chelating picolyl moiety into fluorescent or biotin-based azide reagents strongly increased the sensitivity of the imaging routine. We demonstrate the applicability and evaluate the performance of this approach using different lipid classes and experimental setups. As azide picolyl reporters allow for reduced copper catalyst concentrations, they also enable coimaging of alkyne lipids with multiple fluorescent proteins including enhanced green fluorescent protein. Alternatively, and as we also show, microscopy of alkyne lipids can be combined with protein detection by immunocytochemistry. In summary, we present a robust, sensitive, and highly versatile protocol for the labeling of alkyne lipids with azide-coupled reporters for fluorescence microscopy that can be combined with different protein detection and imaging techniques. PMID:27565170

Radiation dose reduction in thoracic and lumbar spine instrumentation using navigation based on an intraoperative cone beam CT imaging system: a prospective randomized clinical trial.

PubMed

Pireau, Nathalie; Cordemans, Virginie; Banse, Xavier; Irda, Nadia; Lichtherte, Sébastien; Kaminski, Ludovic

2017-11-01

Spine surgery still remains a challenge for every spine surgeon, aware of the potential serious outcomes of misplaced instrumentation. Though many studies have highlighted that using intraoperative cone beam CT imaging and navigation systems provides higher accuracy than conventional freehand methods for placement of pedicle screws in spine surgery, few studies are concerned about how to reduce radiation exposure for patients with the use of such technology. One of the main focuses of this study is based on the ALARA principle (as low as reasonably achievable). A prospective randomized trial was conducted in the hybrid operating room between December 2015 and December 2016, including 50 patients operated on for posterior instrumented thoracic and/or lumbar spinal fusion. Patients were randomized to intraoperative 3D acquisition high-dose (standard dose) or low-dose protocol, and a total of 216 pedicle screws were analyzed in terms of screw position. Two different methods were used to measure ionizing radiation: the total skin dose (derived from the dose-area product) and the radiation dose evaluated by thermoluminescent dosimeters on the surgical field. According to Gertzbein and Heary classifications, low-dose protocol provided a significant higher accuracy of pedicle screw placement than the high-dose protocol (96.1 versus 92%, respectively). Seven screws (3.2%), all implanted with the high-dose protocol, needed to be revised intraoperatively. The use of low-dose acquisition protocols reduced patient exposure by a factor of five. This study emphasizes the paramount importance of using low-dose protocols for intraoperative cone beam CT imaging coupled with the navigation system, as it at least does not affect the accuracy of pedicle screw placement and irradiates drastically less.

SU-E-P-49: Evaluation of Image Quality and Radiation Dose of Various Unenhanced Head CT Protocols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, L; Khan, M; Alapati, K

2015-06-15

Purpose: To evaluate the diagnostic value of various unenhanced head CT protocols and predicate acceptable radiation dose level for head CT exam. Methods: Our retrospective analysis included 3 groups, 20 patients per group, who underwent clinical routine unenhanced adult head CT examination. All exams were performed axially with 120 kVp. Three protocols, 380 mAs without iterative reconstruction and automAs, 340 mAs with iterative reconstruction without automAs, 340 mAs with iterative reconstruction and automAs, were applied on each group patients respectively. The images were reconstructed with H30, J30 for brain window and H60, J70 for bone window. Images acquired with threemore » protocols were randomized and blindly reviewed by three radiologists. A 5 point scale was used to rate each exam The percentage of exam score above 3 and average scores of each protocol were calculated for each reviewer and tissue types. Results: For protocols without automAs, the average scores of bone window with iterative reconstruction were higher than those without iterative reconstruction for each reviewer although the radiation dose was 10 percentage lower. 100 percentage exams were scored 3 or higher and the average scores were above 4 for both brain and bone reconstructions. The CTDIvols are 64.4 and 57.8 mGy of 380 and 340 mAs, respectively. With automAs, the radiation dose varied with head size, resulting in 47.5 mGy average CTDIvol between 39.5 and 56.5 mGy. 93 and 98 percentage exams were scored great than 3 for brain and bone windows, respectively. The diagnostic confidence level and image quality of exams with AutomAs were less than those without AutomAs for each reviewer. Conclusion: According to these results, the mAs was reduced to 300 with automAs OFF for head CT exam. The radiation dose was 20 percentage lower than the original protocol and the CTDIvol was reduced to 51.2 mGy.« less

Development of a dynamic quality assurance testing protocol for multisite clinical trial DCE-CT accreditation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Driscoll, B.; Keller, H.; Jaffray, D.

2013-08-15

Purpose: Credentialing can have an impact on whether or not a clinical trial produces useful quality data that is comparable between various institutions and scanners. With the recent increase of dynamic contrast enhanced-computed tomography (DCE-CT) usage as a companion biomarker in clinical trials, effective quality assurance, and control methods are required to ensure there is minimal deviation in the results between different scanners and protocols at various institutions. This paper attempts to address this problem by utilizing a dynamic flow imaging phantom to develop and evaluate a DCE-CT quality assurance (QA) protocol.Methods: A previously designed flow phantom, capable of producingmore » predictable and reproducible time concentration curves from contrast injection was fully validated and then utilized to design a DCE-CT QA protocol. The QA protocol involved a set of quantitative metrics including injected and total mass error, as well as goodness of fit comparison to the known truth concentration curves. An additional region of interest (ROI) sensitivity analysis was also developed to provide additional details on intrascanner variability and determine appropriate ROI sizes for quantitative analysis. Both the QA protocol and ROI sensitivity analysis were utilized to test variations in DCE-CT results using different imaging parameters (tube voltage and current) as well as alternate reconstruction methods and imaging techniques. The developed QA protocol and ROI sensitivity analysis was then applied at three institutions that were part of clinical trial involving DCE-CT and results were compared.Results: The inherent specificity of robustness of the phantom was determined through calculation of the total intraday variability and determined to be less than 2.2 ± 1.1% (total calculated output contrast mass error) with a goodness of fit (R{sup 2}) of greater than 0.99 ± 0.0035 (n= 10). The DCE-CT QA protocol was capable of detecting significant deviations from the expected phantom result when scanning at low mAs and low kVp in terms of quantitative metrics (Injected Mass Error 15.4%), goodness of fit (R{sup 2}) of 0.91, and ROI sensitivity (increase in minimum input function ROI radius by 146 ± 86%). These tests also confirmed that the ASIR reconstruction process was beneficial in reducing noise without substantially increasing partial volume effects and that vendor specific modes (e.g., axial shuttle) did not significantly affect the phantom results. The phantom and QA protocol were finally able to quickly (<90 min) and successfully validate the DCE-CT imaging protocol utilized at the three separate institutions of a multicenter clinical trial; thereby enhancing the confidence in the patient data collected.Conclusions: A DCE QA protocol was developed that, in combination with a dynamic multimodality flow phantom, allows the intrascanner variability to be separated from other sources of variability such as the impact of injection protocol and ROI selection. This provides a valuable resource that can be utilized at various clinical trial institutions to test conformance with imaging protocols and accuracy requirements as well as ensure that the scanners are performing as expected for dynamic scans.« less

Accounting for patient size in the optimization of dose and image quality of pelvis cone beam CT protocols on the Varian OBI system.

PubMed

Wood, Tim J; Moore, Craig S; Horsfield, Carl J; Saunderson, John R; Beavis, Andrew W

2015-01-01

The purpose of this study was to develop size-based radiotherapy kilovoltage cone beam CT (CBCT) protocols for the pelvis. Image noise was measured in an elliptical phantom of varying size for a range of exposure factors. Based on a previously defined "small pelvis" reference patient and CBCT protocol, appropriate exposure factors for small, medium, large and extra-large patients were derived which approximate the image noise behaviour observed on a Philips CT scanner (Philips Medical Systems, Best, Netherlands) with automatic exposure control (AEC). Selection criteria, based on maximum tube current-time product per rotation selected during the radiotherapy treatment planning scan, were derived based on an audit of patient size. It has been demonstrated that 110 kVp yields acceptable image noise for reduced patient dose in pelvic CBCT scans of small, medium and large patients, when compared with manufacturer's default settings (125 kVp). Conversely, extra-large patients require increased exposure factors to give acceptable images. 57% of patients in the local population now receive much lower radiation doses, whereas 13% require higher doses (but now yield acceptable images). The implementation of size-based exposure protocols has significantly reduced radiation dose to the majority of patients with no negative impact on image quality. Increased doses are required on the largest patients to give adequate image quality. The development of size-based CBCT protocols that use the planning CT scan (with AEC) to determine which protocol is appropriate ensures adequate image quality whilst minimizing patient radiation dose.

Measurement of eye lens dose for Varian On-Board Imaging with different cone-beam computed tomography acquisition techniques

PubMed Central

Deshpande, Sudesh; Dhote, Deepak; Thakur, Kalpna; Pawar, Amol; Kumar, Rajesh; Kumar, Munish; Kulkarni, M. S.; Sharma, S. D.; Kannan, V.

2016-01-01

The objective of this work was to measure patient eye lens dose for different cone-beam computed tomography (CBCT) acquisition protocols of Varian's On-Board Imaging (OBI) system using optically stimulated luminescence dosimeter (OSLD) and to study the variation in eye lens dose with patient geometry and distance of isocenter to the eye lens. During the experimental measurements, OSLD was placed on the patient between the eyebrows of both eyes in line of nose during CBCT image acquisition to measure eye lens doses. The eye lens dose measurements were carried out for three different cone-beam acquisition protocols (standard dose head, low-dose head [LDH], and high-quality head [HQH]) of Varian OBI. Measured doses were correlated with patient geometry and distance between isocenter and eye lens. Measured eye lens doses for standard head and HQH protocols were in the range of 1.8–3.2 mGy and 4.5–9.9 mGy, respectively. However, the measured eye lens dose for the LDH protocol was in the range of 0.3–0.7 mGy. The measured data indicate that eye lens dose to patient depends on the selected imaging protocol. It was also observed that eye lens dose does not depend on patient geometry but strongly depends on distance between eye lens and treatment field isocenter. However, undoubted advantages of imaging system should not be counterbalanced by inappropriate selection of imaging protocol, especially for very intense imaging protocol. PMID:27651564

Use of a channelized Hotelling observer to assess CT image quality and optimize dose reduction for iteratively reconstructed images.

PubMed

Favazza, Christopher P; Ferrero, Andrea; Yu, Lifeng; Leng, Shuai; McMillan, Kyle L; McCollough, Cynthia H

2017-07-01

The use of iterative reconstruction (IR) algorithms in CT generally decreases image noise and enables dose reduction. However, the amount of dose reduction possible using IR without sacrificing diagnostic performance is difficult to assess with conventional image quality metrics. Through this investigation, achievable dose reduction using a commercially available IR algorithm without loss of low contrast spatial resolution was determined with a channelized Hotelling observer (CHO) model and used to optimize a clinical abdomen/pelvis exam protocol. A phantom containing 21 low contrast disks-three different contrast levels and seven different diameters-was imaged at different dose levels. Images were created with filtered backprojection (FBP) and IR. The CHO was tasked with detecting the low contrast disks. CHO performance indicated dose could be reduced by 22% to 25% without compromising low contrast detectability (as compared to full-dose FBP images) whereas 50% or more dose reduction significantly reduced detection performance. Importantly, default settings for the scanner and protocol investigated reduced dose by upward of 75%. Subsequently, CHO-based protocol changes to the default protocol yielded images of higher quality and doses more consistent with values from a larger, dose-optimized scanner fleet. CHO assessment provided objective data to successfully optimize a clinical CT acquisition protocol.

Web-based monitoring and management system for integrated enterprise-wide imaging networks

NASA Astrophysics Data System (ADS)

Ma, Keith; Slik, David; Lam, Alvin; Ng, Won

2003-05-01

Mass proliferation of IP networks and the maturity of standards has enabled the creation of sophisticated image distribution networks that operate over Intranets, Extranets, Communities of Interest (CoI) and even the public Internet. Unified monitoring, provisioning and management of such systems at the application and protocol levels represent a challenge. This paper presents a web based monitoring and management tool that employs established telecom standards for the creation of an open system that enables proactive management, provisioning and monitoring of image management systems at the enterprise level and across multi-site geographically distributed deployments. Utilizing established standards including ITU-T M.3100, and web technologies such as XML/XSLT, JSP/JSTL, and J2SE, the system allows for seamless device and protocol adaptation between multiple disparate devices. The goal has been to develop a unified interface that provides network topology views, multi-level customizable alerts, real-time fault detection as well as real-time and historical reporting of all monitored resources, including network connectivity, system load, DICOM transactions and storage capacities.

Methods for the visualization and analysis of extracellular matrix protein structure and degradation.

PubMed

Leonard, Annemarie K; Loughran, Elizabeth A; Klymenko, Yuliya; Liu, Yueying; Kim, Oleg; Asem, Marwa; McAbee, Kevin; Ravosa, Matthew J; Stack, M Sharon

2018-01-01

This chapter highlights methods for visualization and analysis of extracellular matrix (ECM) proteins, with particular emphasis on collagen type I, the most abundant protein in mammals. Protocols described range from advanced imaging of complex in vivo matrices to simple biochemical analysis of individual ECM proteins. The first section of this chapter describes common methods to image ECM components and includes protocols for second harmonic generation, scanning electron microscopy, and several histological methods of ECM localization and degradation analysis, including immunohistochemistry, Trichrome staining, and in situ zymography. The second section of this chapter details both a common transwell invasion assay and a novel live imaging method to investigate cellular behavior with respect to collagen and other ECM proteins of interest. The final section consists of common electrophoresis-based biochemical methods that are used in analysis of ECM proteins. Use of the methods described herein will enable researchers to gain a greater understanding of the role of ECM structure and degradation in development and matrix-related diseases such as cancer and connective tissue disorders. © 2018 Elsevier Inc. All rights reserved.

SU-F-207-16: CT Protocols Optimization Using Model Observer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tseng, H; Fan, J; Kupinski, M

2015-06-15

Purpose: To quantitatively evaluate the performance of different CT protocols using task-based measures of image quality. This work studies the task of size and the contrast estimation of different iodine concentration rods inserted in head- and body-sized phantoms using different imaging protocols. These protocols are designed to have the same dose level (CTDIvol) but using different X-ray tube voltage settings (kVp). Methods: Different concentrations of iodine objects inserted in a head size phantom and a body size phantom are imaged on a 64-slice commercial CT scanner. Scanning protocols with various tube voltages (80, 100, and 120 kVp) and current settingsmore » are selected, which output the same absorbed dose level (CTDIvol). Because the phantom design (size of the iodine objects, the air gap between the inserted objects and the phantom) is not ideal for a model observer study, the acquired CT images are used to generate simulation images with four different sizes and five different contracts iodine objects. For each type of the objects, 500 images (100 x 100 pixels) are generated for the observer study. The observer selected in this study is the channelized scanning linear observer which could be applied to estimate the size and the contrast. The figure of merit used is the correct estimation ratio. The mean and the variance are estimated by the shuffle method. Results: The results indicate that the protocols with 100 kVp tube voltage setting provides the best performance for iodine insert size and contrast estimation for both head and body phantom cases. Conclusion: This work presents a practical and robust quantitative approach using channelized scanning linear observer to study contrast and size estimation performance from different CT protocols. Different protocols at same CTDIvol setting could Result in different image quality performance. The relationship between the absorbed dose and the diagnostic image quality is not linear.« less

Reducing the Radiation Dose for CT Colonography: Effect of Low Tube Voltage and Iterative Reconstruction.

PubMed

Yamamura, Sadahiro; Oda, Seitaro; Imuta, Masanori; Utsunomiya, Daisuke; Yoshida, Morikatsu; Namimoto, Tomohiro; Yuki, Hideaki; Kidoh, Masafumi; Funama, Yoshinori; Baba, Hideo; Yamashita, Yasuyuki

2016-02-01

The purpose of this study was to assess the effect of a low-tube-voltage technique and iterative reconstruction (IR) on the radiation dose and image quality of computed tomography colonography (CTC). We studied 30 patients (14 women and 16 men; mean age, 64.5 ± 13.1 years; range, 39-90 years) with colorectal cancer referred for surgical treatment. All underwent CTC with fecal tagging under a standard 120-kVp protocol in the supine position and a 100-kVp protocol in the prone position. The 120-kVp images were reconstructed with filtered back projection (FBP). The 100-kVp images were postprocessed using FBP and a hybrid type of IR (adaptive iterative dose reduction 3D). The effective radiation dose (ED), image noise, and contrast-to-noise ratio (CNR) were compared among the three protocols. The visual image quality was scored on a four-point scale. The mean ED was significantly lower under the 100-kVp protocol than the 120-kVp protocol, resulting in a 27% radiation dose decrease (3.5 ± 2.0 vs 2.5 ± 1.5 mSv; P < .01). Image noise decreased by 48%, and the mean attenuation of tagged fluid increased from 452 to 558 HU on images acquired at 100 kVp with IR compared to that in the 120-kVp protocol; these differences were significant. The mean CNR was significantly higher under the 100 kVp with IR than the other two protocols. We found no significant differences in the visual scores for diagnostic utility between the 100 kVp with IR and the 120 kVp with FBP protocol (P = .10). Low-tube-voltage CTC reduced the radiation dose by approximately 27% while maintaining the image quality. Copyright © 2016 AUR. Published by Elsevier Inc. All rights reserved.

A Graphical User Interface for Software-assisted Tracking of Protein Concentration in Dynamic Cellular Protrusions.

PubMed

Saha, Tanumoy; Rathmann, Isabel; Galic, Milos

2017-07-11

Filopodia are dynamic, finger-like cellular protrusions associated with migration and cell-cell communication. In order to better understand the complex signaling mechanisms underlying filopodial initiation, elongation and subsequent stabilization or retraction, it is crucial to determine the spatio-temporal protein activity in these dynamic structures. To analyze protein function in filopodia, we recently developed a semi-automated tracking algorithm that adapts to filopodial shape-changes, thus allowing parallel analysis of protrusion dynamics and relative protein concentration along the whole filopodial length. Here, we present a detailed step-by-step protocol for optimized cell handling, image acquisition and software analysis. We further provide instructions for the use of optional features during image analysis and data representation, as well as troubleshooting guidelines for all critical steps along the way. Finally, we also include a comparison of the described image analysis software with other programs available for filopodia quantification. Together, the presented protocol provides a framework for accurate analysis of protein dynamics in filopodial protrusions using image analysis software.

Optimized protocol for combined PALM-dSTORM imaging.

PubMed

Glushonkov, O; Réal, E; Boutant, E; Mély, Y; Didier, P

2018-06-08

Multi-colour super-resolution localization microscopy is an efficient technique to study a variety of intracellular processes, including protein-protein interactions. This technique requires specific labels that display transition between fluorescent and non-fluorescent states under given conditions. For the most commonly used label types, photoactivatable fluorescent proteins and organic fluorophores, these conditions are different, making experiments that combine both labels difficult. Here, we demonstrate that changing the standard imaging buffer of thiols/oxygen scavenging system, used for organic fluorophores, to the commercial mounting medium Vectashield increased the number of photons emitted by the fluorescent protein mEos2 and enhanced the photoconversion rate between its green and red forms. In addition, the photophysical properties of organic fluorophores remained unaltered with respect to the standard imaging buffer. The use of Vectashield together with our optimized protocol for correction of sample drift and chromatic aberrations enabled us to perform two-colour 3D super-resolution imaging of the nucleolus and resolve its three compartments.

Very low intravenous contrast volume protocol for computed tomography angiography providing comprehensive cardiac and vascular assessment prior to transcatheter aortic valve replacement in patients with chronic kidney disease.

PubMed

Pulerwitz, Todd C; Khalique, Omar K; Nazif, Tamim N; Rozenshtein, Anna; Pearson, Gregory D N; Hahn, Rebecca T; Vahl, Torsten P; Kodali, Susheel K; George, Isaac; Leon, Martin B; D'Souza, Belinda; Po, Ming Jack; Einstein, Andrew J

2016-01-01

Transcatheter aortic valve replacement (TAVR) is a lifesaving procedure for many patients high risk for surgical aortic valve replacement. The prevalence of chronic kidney disease (CKD) is high in this population, and thus a very low contrast volume (VLCV) computed tomography angiography (CTA) protocol providing comprehensive cardiac and vascular imaging would be valuable. 52 patients with severe, symptomatic aortic valve disease, undergoing pre-TAVR CTA assessment from 2013-4 at Columbia University Medical Center were studied, including all 26 patients with CKD (eGFR<30 mL/min) who underwent a novel VLCV protocol (20 mL of iohexol at 2.5 mL/s), and 26 standard-contrast-volume (SCV) protocol patients. Using a 320-slice volumetric scanner, the protocol included ECG-gated volume scanning of the aortic root followed by medium-pitch helical vascular scanning through the femoral arteries. Two experienced cardiologists performed aortic annulus and root measurements. Vascular image quality was assessed by two radiologists using a 4-point scale. VLCV patients had mean (±SD) age 86 ± 6.5, BMI 23.9 ± 3.4 kg/m(2) with 54% men; SCV patients age 83 ± 8.8, BMI 28.7 ± 5.3 kg/m(2), 65% men. There was excellent intra- and inter-observer agreement for annular and root measurements, and excellent agreement with 3D-transesophageal echocardiographic measurements. Both radiologists found diagnostic-quality vascular imaging in 96% of VLCV and 100% of SCV cases, with excellent inter-observer agreement. This study is the first of its kind to report the feasibility and reproducibility of measurements for a VLCV protocol for comprehensive pre-TAVR CTA. There was excellent agreement of cardiac measurements and almost all studies were diagnostic quality for vascular access assessment. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

An orthopedist's guide to shoulder ultrasound: a systematic review of examination protocols.

PubMed

Amoo-Achampong, Kelms; Nwachukwu, Benedict U; McCormick, Frank

2016-11-01

The utilization of musculoskeletal ultrasound has expanded within the setting of the orthopedic clinic as a cost-effective, point-of-care diagnostic tool for shoulder pathology. In experienced hands, ultrasound exhibits capabilities equivalent to that of magnetic resonance imaging in the diagnosis of many shoulder diseases including full-thickness and partial-thickness rotator cuff tears. Although similarly effective in identifying additional shoulder disease processes, major obstacles to its widespread use include user dependence and intrinsic limitation to extra-articular diagnosis. The purpose of this review is to present a step-by-step guide of how to perform a comprehensive shoulder examination and to discuss the appropriate use, economic benefit and implementation of ultrasound within the clinic. A systematic search (June 2016) of PubMed, Scopus, and EMBASE databases was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for literature presenting shoulder ultrasound examination protocols. Included studies were peer-reviewed articles or academic society endorsed protocols presenting comprehensive sonographic examinations of the adult shoulder. Papers with limited or single structure examination descriptions, non-English language, and publication dates before 1980 were excluded. Final papers meeting criteria were secondarily screened for publication after 2005 to reflect the current state of ultrasound imaging. The search yielded 1,725 unique articles with 17 studies meeting final selection criteria. Information from identified studies was summarized to formulate a 4-part shoulder examination protocol, including steps most pertinent to orthopedic in-office diagnoses. In agreement with previous studies, the inexperienced orthopedic surgeon can be quickly trained to expert level proficiency in shoulder ultrasound diagnosis. Using an established protocol, a comprehensive, yet effective shoulder ultrasound examination can be performed within ten minutes. Further, ultrasound provides opportunity to off-set costs through the engagement of revenue generating activity for the orthopedic practice.

Magnetic resonance imaging of athletic pubalgia and the sports hernia: current understanding and practice.

PubMed

Khan, Waseem; Zoga, Adam C; Meyers, William C

2013-02-01

Magnetic resonance imaging (MRI) has become the standard imaging modality for activity-related groin pain. Lesions, including rectus abdominis/adductor aponeurosis injury and osteitis pubis, can be accurately identified and delineated in patients with clinical conditions termed athletic pubalgia, core injury, and sports hernia. A dedicated noncontrast athletic pubalgia MRI protocol is easy to implement and should be available at musculoskeletal MR imaging centers. This article will review pubic anatomy, imaging considerations, specific lesions, and common MRI findings encountered in the setting of musculoskeletal groin pain. Copyright © 2013 Elsevier Inc. All rights reserved.

Implementation of an anonymisation tool for clinical trials using a clinical trial processor integrated with an existing trial patient data information system.

PubMed

Aryanto, Kadek Y E; Broekema, André; Oudkerk, Matthijs; van Ooijen, Peter M A

2012-01-01

To present an adapted Clinical Trial Processor (CTP) test set-up for receiving, anonymising and saving Digital Imaging and Communications in Medicine (DICOM) data using external input from the original database of an existing clinical study information system to guide the anonymisation process. Two methods are presented for an adapted CTP test set-up. In the first method, images are pushed from the Picture Archiving and Communication System (PACS) using the DICOM protocol through a local network. In the second method, images are transferred through the internet using the HTTPS protocol. In total 25,000 images from 50 patients were moved from the PACS, anonymised and stored within roughly 2 h using the first method. In the second method, an average of 10 images per minute were transferred and processed over a residential connection. In both methods, no duplicated images were stored when previous images were retransferred. The anonymised images are stored in appropriate directories. The CTP can transfer and process DICOM images correctly in a very easy set-up providing a fast, secure and stable environment. The adapted CTP allows easy integration into an environment in which patient data are already included in an existing information system.

Optimization of the scan protocols for CT-based material extraction in small animal PET/CT studies

NASA Astrophysics Data System (ADS)

Yang, Ching-Ching; Yu, Jhih-An; Yang, Bang-Hung; Wu, Tung-Hsin

2013-12-01

We investigated the effects of scan protocols on CT-based material extraction to minimize radiation dose while maintaining sufficient image information in small animal studies. The phantom simulation experiments were performed with the high dose (HD), medium dose (MD) and low dose (LD) protocols at 50, 70 and 80 kVp with varying mA s. The reconstructed CT images were segmented based on Hounsfield unit (HU)-physical density (ρ) calibration curves and the dual-energy CT-based (DECT) method. Compared to the (HU;ρ) method performed on CT images acquired with the 80 kVp HD protocol, a 2-fold improvement in segmentation accuracy and a 7.5-fold reduction in radiation dose were observed when the DECT method was performed on CT images acquired with the 50/80 kVp LD protocol, showing the possibility to reduce radiation dose while achieving high segmentation accuracy.

A Method of Managing Severe Traumatic Brain Injury in the Absence of Intracranial Pressure Monitoring: The Imaging and Clinical Examination Protocol.

PubMed

Chesnut, Randall M; Temkin, Nancy; Dikmen, Sureyya; Rondina, Carlos; Videtta, Walter; Petroni, Gustavo; Lujan, Silvia; Alanis, Victor; Falcao, Antonio; de la Fuenta, Gustavo; Gonzalez, Luis; Jibaja, Manuel; Lavarden, Arturo; Sandi, Freddy; Mérida, Roberto; Romero, Ricardo; Pridgeon, Jim; Barber, Jason; Machamer, Joan; Chaddock, Kelley

2018-01-01

The imaging and clinical examination (ICE) algorithm used in the Benchmark Evidence from South American Trials: Treatment of Intracranial Pressure (BEST TRIP) randomized controlled trial is the only prospectively investigated clinical protocol for traumatic brain injury management without intracranial pressure (ICP) monitoring. As the default literature standard, it warrants careful evaluation. We present the ICE protocol in detail and analyze the demographics, outcome, treatment intensity, frequency of intervention usage, and related adverse events in the ICE-protocol cohort. The 167 ICE protocol patients were young (median 29 years) with a median Glasgow Coma Scale motor score of 4 but with anisocoria or abnormal pupillary reactivity in 40%. This protocol produced outcomes not significantly different from those randomized to the monitor-based protocol (favorable 6-month extended Glasgow Outcome Score in 39%; 41% mortality rate). Agents commonly employed to treat suspected intracranial hypertension included low-/moderate-dose hypertonic saline (72%) and mannitol (57%), mild hyperventilation (adjusted partial pressure of carbon dioxide 30-35 mm Hg in 73%), and pressors to maintain cerebral perfusion (62%). High-dose hyperosmotics or barbiturates were uncommonly used. Adverse event incidence was low and comparable to the BEST TRIP monitored group. Although this protocol should produce similar/acceptable results under circumstances comparable to those in the trial, influences such as longer pre-hospital times and non-specialist transport personnel, plus an intensive care unit model of aggressive physician-intensive care by small groups of neurotrauma-focused intensivists, which differs from most high-resource models, support caution in expecting the same results in dissimilar settings. Finally, this protocol's ICP-titration approach to suspected intracranial hypertension (vs. crisis management for monitored ICP) warrants further study.

Image-based change estimation (ICE): monitoring land use, land cover and agent of change information for all lands

Treesearch

Kevin Megown; Andy Lister; Paul Patterson; Tracey Frescino; Dennis Jacobs; Jeremy Webb; Nicholas Daniels; Mark Finco

2015-01-01

The Image-based Change Estimation (ICE) protocols have been designed to respond to several Agency and Department information requirements. These include provisions set forth by the 2014 Farm Bill, the Forest Service Action Plan and Strategic Plan, the 2012 Planning Rule, and the 2015 Planning Directives. ICE outputs support the information needs by providing estimates...

SU-F-18C-01: Minimum Detectability Analysis for Comprehensive Sized Based Optimization of Image Quality and Radiation Dose Across CT Protocols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smitherman, C; Chen, B; Samei, E

2014-06-15

Purpose: This work involved a comprehensive modeling of task-based performance of CT across a wide range of protocols. The approach was used for optimization and consistency of dose and image quality within a large multi-vendor clinical facility. Methods: 150 adult protocols from the Duke University Medical Center were grouped into sub-protocols with similar acquisition characteristics. A size based image quality phantom (Duke Mercury Phantom) was imaged using these sub-protocols for a range of clinically relevant doses on two CT manufacturer platforms (Siemens, GE). The images were analyzed to extract task-based image quality metrics such as the Task Transfer Function (TTF),more » Noise Power Spectrum, and Az based on designer nodule task functions. The data were analyzed in terms of the detectability of a lesion size/contrast as a function of dose, patient size, and protocol. A graphical user interface (GUI) was developed to predict image quality and dose to achieve a minimum level of detectability. Results: Image quality trends with variations in dose, patient size, and lesion contrast/size were evaluated and calculated data behaved as predicted. The GUI proved effective to predict the Az values representing radiologist confidence for a targeted lesion, patient size, and dose. As an example, an abdomen pelvis exam for the GE scanner, with a task size/contrast of 5-mm/50-HU, and an Az of 0.9 requires a dose of 4.0, 8.9, and 16.9 mGy for patient diameters of 25, 30, and 35 cm, respectively. For a constant patient diameter of 30 cm, the minimum detected lesion size at those dose levels would be 8.4, 5, and 3.9 mm, respectively. Conclusion: The designed CT protocol optimization platform can be used to evaluate minimum detectability across dose levels and patient diameters. The method can be used to improve individual protocols as well as to improve protocol consistency across CT scanners.« less

Clock Scan Protocol for Image Analysis: ImageJ Plugins.

PubMed

Dobretsov, Maxim; Petkau, Georg; Hayar, Abdallah; Petkau, Eugen

2017-06-19

The clock scan protocol for image analysis is an efficient tool to quantify the average pixel intensity within, at the border, and outside (background) a closed or segmented convex-shaped region of interest, leading to the generation of an averaged integral radial pixel-intensity profile. This protocol was originally developed in 2006, as a visual basic 6 script, but as such, it had limited distribution. To address this problem and to join similar recent efforts by others, we converted the original clock scan protocol code into two Java-based plugins compatible with NIH-sponsored and freely available image analysis programs like ImageJ or Fiji ImageJ. Furthermore, these plugins have several new functions, further expanding the range of capabilities of the original protocol, such as analysis of multiple regions of interest and image stacks. The latter feature of the program is especially useful in applications in which it is important to determine changes related to time and location. Thus, the clock scan analysis of stacks of biological images may potentially be applied to spreading of Na + or Ca ++ within a single cell, as well as to the analysis of spreading activity (e.g., Ca ++ waves) in populations of synaptically-connected or gap junction-coupled cells. Here, we describe these new clock scan plugins and show some examples of their applications in image analysis.

Computed tomographic venography for varicose veins of the lower extremities: prospective comparison of 80-kVp and conventional 120-kVp protocols.

PubMed

Cho, Eun-Suk; Kim, Joo Hee; Kim, Sungjun; Yu, Jeong-Sik; Chung, Jae-Joon; Yoon, Choon-Sik; Lee, Hyeon-Kyeong; Lee, Kyung Hee

2012-01-01

To prospectively investigate the feasibility of an 80-kilovolt (peak) (kVp) protocol in computed tomographic venography for varicose veins of the lower extremities by comparison with conventional 120-kVp protocol. Attenuation values and signal-to-noise ratio of iodine contrast medium (CM) were determined in a water phantom for 2 tube voltages (80 kVp and 120 kVp). Among 100 patients, 50 patients were scanned with 120 kVp and 150 effective milliampere second (mAs(eff)), and the other 50 patients were scanned with 80 kVp and 390 mAs(eff) after the administration of 1.7-mL/kg CM (370 mg of iodine per milliliter). The 2 groups were compared for venous attenuation, contrast-to-noise ratio, and subjective degree of venous enhancement, image noise, and overall diagnostic image quality. In the phantom, the attenuation value and signal-to-noise ratio value for iodine CM at 80 kVp were 63.8% and 33.0% higher, respectively, than those obtained at 120 kVp. The mean attenuation of the measured veins of the lower extremities was 148.3 Hounsfield units (HU) for the 80-kVp protocol and 94.8 HU for the 120-kVp protocol. Contrast-to-noise ratio was also significantly higher with the 80-kVp protocol. The overall diagnostic image quality of the 3-dimensional volume-rendered images was good with both protocols. The subjective score for venous enhancement was higher at the 80-kVp protocol. The mean volume computed tomography dose index of the 80-kVp (5.6 mGy) protocol was 23.3% lower than that of the 120-kVp (7.3 mGy) protocol. The use of the 80-kVp protocol improved overall venous attenuation, especially in perforating vein, and provided similarly high diagnostic image quality with a lower radiation dose when compared to the conventional 120-kVp protocol.

A proposed protocol for acceptance and constancy control of computed tomography systems: a Nordic Association for Clinical Physics (NACP) work group report.

PubMed

Kuttner, Samuel; Bujila, Robert; Kortesniemi, Mika; Andersson, Henrik; Kull, Love; Østerås, Bjørn Helge; Thygesen, Jesper; Tarp, Ivanka Sojat

2013-03-01

Quality assurance (QA) of computed tomography (CT) systems is one of the routine tasks for medical physicists in the Nordic countries. However, standardized QA protocols do not yet exist and the QA methods, as well as the applied tolerance levels, vary in scope and extent at different hospitals. To propose a standardized protocol for acceptance and constancy testing of CT scanners in the Nordic Region. Following a Nordic Association for Clinical Physics (NACP) initiative, a group of medical physicists, with representatives from four Nordic countries, was formed. Based on international literature and practical experience within the group, a comprehensive standardized test protocol was developed. The proposed protocol includes tests related to the mechanical functionality, X-ray tube, detector, and image quality for CT scanners. For each test, recommendations regarding the purpose, equipment needed, an outline of the test method, the measured parameter, tolerance levels, and the testing frequency are stated. In addition, a number of optional tests are briefly discussed that may provide further information about the CT system. Based on international references and medical physicists' practical experiences, a comprehensive QA protocol for CT systems is proposed, including both acceptance and constancy tests. The protocol may serve as a reference for medical physicists in the Nordic countries.

SU-E-J-06: Additional Imaging Guidance Dose to Patient Organs Resulting From X-Ray Tubes Used in CyberKnife Image Guidance System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, A; Ding, G

Purpose: The use of image-guided radiation therapy (IGRT) has become increasingly common, but the additional radiation exposure resulting from repeated image guidance procedures raises concerns. Although there are many studies reporting imaging dose from different image guidance devices, imaging dose for the CyberKnife Robotic Radiosurgery System is not available. This study provides estimated organ doses resulting from image guidance procedures on the CyberKnife system. Methods: Commercially available Monte Carlo software, PCXMC, was used to calculate average organ doses resulting from x-ray tubes used in the CyberKnife system. There are seven imaging protocols with kVp ranging from 60 – 120 kVmore » and 15 mAs for treatment sites in the Cranium, Head and Neck, Thorax, and Abdomen. The output of each image protocol was measured at treatment isocenter. For each site and protocol, Adult body sizes ranging from anorexic to extremely obese were simulated since organ dose depends on patient size. Doses for all organs within the imaging field-of-view of each site were calculated for a single image acquisition from both of the orthogonal x-ray tubes. Results: Average organ doses were <1.0 mGy for every treatment site and imaging protocol. For a given organ, dose increases as kV increases or body size decreases. Higher doses are typically reported for skeletal components, such as the skull, ribs, or clavicles, than for softtissue organs. Typical organ doses due to a single exposure are estimated as 0.23 mGy to the brain, 0.29 mGy to the heart, 0.08 mGy to the kidneys, etc., depending on the imaging protocol and site. Conclusion: The organ doses vary with treatment site, imaging protocol and patient size. Although the organ dose from a single image acquisition resulting from two orthogonal beams is generally insignificant, the sum of repeated image acquisitions (>100) could reach 10–20 cGy for a typical treatment fraction.« less

[Medical imaging in tumor precision medicine: opportunities and challenges].

PubMed

Xu, Jingjing; Tan, Yanbin; Zhang, Minming

2017-05-25

Tumor precision medicine is an emerging approach for tumor diagnosis, treatment and prevention, which takes account of individual variability of environment, lifestyle and genetic information. Tumor precision medicine is built up on the medical imaging innovations developed during the past decades, including the new hardware, new imaging agents, standardized protocols, image analysis and multimodal imaging fusion technology. Also the development of automated and reproducible analysis algorithm has extracted large amount of information from image-based features. With the continuous development and mining of tumor clinical and imaging databases, the radiogenomics, radiomics and artificial intelligence have been flourishing. Therefore, these new technological advances bring new opportunities and challenges to the application of imaging in tumor precision medicine.

Magnetic resonance imaging protocols for examination of the neurocranium at 3 T.

PubMed

Schwindt, W; Kugel, H; Bachmann, R; Kloska, S; Allkemper, T; Maintz, D; Pfleiderer, B; Tombach, B; Heindel, W

2003-09-01

The increasing availability of high-field (3 T) MR scanners requires adapting and optimizing clinical imaging protocols to exploit the theoretically higher signal-to-noise ratio (SNR) of the higher field strength. Our aim was to establish reliable and stable protocols meeting the clinical demands for imaging the neurocranium at 3 T. Two hundred patients with a broad range of indications received an examination of the neurocranium with an appropriate assortment of imaging techniques at 3 T. Several imaging parameters were optimized. Keeping scan times comparable to those at 1.5 T we increased spatial resolution. Contrast-enhanced and non-enhanced T1-weighted imaging was best applying gradient-echo and inversion recovery (rather than spin-echo) techniques, respectively. For fluid-attenuated inversion recovery (FLAIR) imaging a TE of 120 ms yielded optimum contrast-to-noise ratio (CNR). High-resolution isotropic 3D data sets were acquired within reasonable scan times. Some artifacts were pronounced, but generally imaging profited from the higher SNR. We present a set of optimized examination protocols for neuroimaging at 3 T, which proved to be reliable in a clinical routine setting.

Effectiveness of a Rapid Lumbar Spine MRI Protocol Using 3D T2-Weighted SPACE Imaging Versus a Standard Protocol for Evaluation of Degenerative Changes of the Lumbar Spine.

PubMed

Sayah, Anousheh; Jay, Ann K; Toaff, Jacob S; Makariou, Erini V; Berkowitz, Frank

2016-09-01

Reducing lumbar spine MRI scanning time while retaining diagnostic accuracy can benefit patients and reduce health care costs. This study compares the effectiveness of a rapid lumbar MRI protocol using 3D T2-weighted sampling perfection with application-optimized contrast with different flip-angle evolutions (SPACE) sequences with a standard MRI protocol for evaluation of lumbar spondylosis. Two hundred fifty consecutive unenhanced lumbar MRI examinations performed at 1.5 T were retrospectively reviewed. Full, rapid, and complete versions of each examination were interpreted for spondylotic changes at each lumbar level, including herniations and neural compromise. The full examination consisted of sagittal T1-weighted, T2-weighted turbo spin-echo (TSE), and STIR sequences; and axial T1- and T2-weighted TSE sequences (time, 18 minutes 40 seconds). The rapid examination consisted of sagittal T1- and T2-weighted SPACE sequences, with axial SPACE reformations (time, 8 minutes 46 seconds). The complete examination consisted of the full examination plus the T2-weighted SPACE sequence. Sensitivities and specificities of the full and rapid examinations were calculated using the complete study as the reference standard. The rapid and full studies had sensitivities of 76.0% and 69.3%, with specificities of 97.2% and 97.9%, respectively, for all degenerative processes. Rapid and full sensitivities were 68.7% and 66.3% for disk herniation, 85.2% and 81.5% for canal compromise, 82.9% and 69.1% for lateral recess compromise, and 76.9% and 69.7% for foraminal compromise, respectively. Isotropic SPACE T2-weighted imaging provides high-quality imaging of lumbar spondylosis, with multiplanar reformatting capability. Our SPACE-based rapid protocol had sensitivities and specificities for herniations and neural compromise comparable to those of the protocol without SPACE. This protocol fits within a 15-minute slot, potentially reducing costs and discomfort for a large subgroup of patients.

Use of the Delay-Tolerant Networking Bundle Protocol from Space

NASA Technical Reports Server (NTRS)

Wood, Lloyd; Ivancic, William D.; Eddy, Wesley M.; Stewart, Dave; Northam, James; Jackson, Chris; daSilvaCuriel, Alex

2009-01-01

The Disaster Monitoring Constellation (DMC), constructed by Survey Satellite Technology Ltd (SSTL), is a multisatellite Earth-imaging low-Earth-orbit sensor network where captured image swaths are stored onboard each satellite and later downloaded from the satellite payloads to a ground station. Store-and-forward of images with capture and later download gives each satellite the characteristics of a node in a Delay/Disruption Tolerant Network (DTN). Originally developed for the Interplanetary Internet, DTNs are now under investigation in an Internet Research Task Force (IRTF) DTN research group (RG), which has developed a bundle architecture and protocol. The DMC is currently unique in its adoption of the Internet Protocol (IP) for its imaging payloads and for satellite command and control, based around reuse of commercial networking and link protocols. These satellites use of IP has enabled earlier experiments with the Cisco router in Low Earth Orbit (CLEO) onboard the constellation's UK-DMC satellite. Earth images are downloaded from the satellites using a custom IPbased high-speed transfer protocol developed by SSTL, Saratoga, which tolerates unusual link environments. Saratoga has been documented in the Internet Engineering Task Force (IETF) for wider adoption. We experiment with use of DTNRG bundle concepts onboard the UKDMC satellite, by examining how Saratoga can be used as a DTN convergence layer to carry the DTNRG Bundle Protocol, so that sensor images can be delivered to ground stations and beyond as bundles. This is the first successful use of the DTNRG Bundle Protocol in a space environment. We use our practical experience to examine the strengths and weaknesses of the Bundle Protocol for DTN use, paying attention to fragmentation, custody transfer, and reliability issues.

Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center.

PubMed

Kahn, Johannes; Kaul, David; Böning, Georg; Rotzinger, Roman; Freyhardt, Patrick; Schwabe, Philipp; Maurer, Martin H; Renz, Diane Miriam; Streitparth, Florian

2017-09-01

Purpose  As a supra-regional level-I trauma center, we evaluated computed tomography (CT) acquisitions of polytraumatized patients for quality and dose optimization purposes. Adapted statistical iterative reconstruction [(AS)IR] levels, tube voltage reduction as well as a split-bolus contrast agent (CA) protocol were applied. Materials and Methods  61 patients were split into 3 different groups that differed with respect to tube voltage (120 - 140 kVp) and level of applied ASIR reconstruction (ASIR 20 - 50 %). The CT protocol included a native acquisition of the head followed by a single contrast-enhanced acquisition of the whole body (64-MSCT). CA (350 mg/ml iodine) was administered as a split bolus injection of 100 ml (2 ml/s), 20 ml NaCl (1 ml/s), 60 ml (4 ml/s), 40 ml NaCl (4 ml/s) with a scan delay of 85 s to detect injuries of both the arterial system and parenchymal organs in a single acquisition. Both the quantitative (SNR/CNR) and qualitative (5-point Likert scale) image quality was evaluated in parenchymal organs that are often injured in trauma patients. Radiation exposure was assessed. Results  The use of IR combined with a reduction of tube voltage resulted in good qualitative and quantitative image quality and a significant reduction in radiation exposure of more than 40 % (DLP 1087 vs. 647 mGyxcm). Image quality could be improved due to a dedicated protocol that included different levels of IR adapted to different slice thicknesses, kernels and the examined area for the evaluation of head, lung, body and bone injury patterns. In synopsis of our results, we recommend the implementation of a polytrauma protocol with a tube voltage of 120 kVp and the following IR levels: cCT 5mm: ASIR 20; cCT 0.625 mm: ASIR 40; lung 2.5 mm: ASIR 30, body 5 mm: ASIR 40; body 1.25 mm: ASIR 50; body 0.625 mm: ASIR 0. Conclusion  A dedicated adaptation of the CT trauma protocol (level of reduction of tube voltage and of IR) according to the examined body region (head, lung, body, bone) combined with a split bolus CA injection protocol allows for a high-quality CT examination and a relevant reduction of radiation exposure in the examination of polytraumatized patients Key Points   · Dedicated adaption of the CT trauma protocol allows for an optimized examination.. · Different levels of iterative reconstruction, tube voltage and the CA injection protocol are crucial.. · A reduction of radiation exposure of more than 40 % with good image quality is possible.. Citation Format · Kahn J, Kaul D, Böning G et al. Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center. Fortschr Röntgenstr 2017; 189: 844 - 854. © Georg Thieme Verlag KG Stuttgart · New York.

3D T2-weighted imaging to shorten multiparametric prostate MRI protocols.

PubMed

Polanec, Stephan H; Lazar, Mathias; Wengert, Georg J; Bickel, Hubert; Spick, Claudio; Susani, Martin; Shariat, Shahrokh; Clauser, Paola; Baltzer, Pascal A T

2018-04-01

To determine whether 3D acquisitions provide equivalent image quality, lesion delineation quality and PI-RADS v2 performance compared to 2D acquisitions in T2-weighted imaging of the prostate at 3 T. This IRB-approved, prospective study included 150 consecutive patients (mean age 63.7 years, 35-84 years; mean PSA 7.2 ng/ml, 0.4-31.1 ng/ml). Two uroradiologists (R1, R2) independently rated image quality and lesion delineation quality using a five-point ordinal scale and assigned a PI-RADS score for 2D and 3D T2-weighted image data sets. Data were compared using visual grading characteristics (VGC) and receiver operating characteristics (ROC)/area under the curve (AUC) analysis. Image quality was similarly good to excellent for 2D T2w (mean score R1, 4.3 ± 0.81; R2, 4.7 ± 0.83) and 3D T2w (mean score R1, 4.3 ± 0.82; R2, 4.7 ± 0.69), p = 0.269. Lesion delineation was rated good to excellent for 2D (mean score R1, 4.16 ± 0.81; R2, 4.19 ± 0.92) and 3D T2w (R1, 4.19 ± 0.94; R2, 4.27 ± 0.94) without significant differences (p = 0.785). ROC analysis showed an equivalent performance for 2D (AUC 0.580-0.623) and 3D (AUC 0.576-0.629) T2w (p > 0.05, respectively). Three-dimensional acquisitions demonstrated equivalent image and lesion delineation quality, and PI-RADS v2 performance, compared to 2D in T2-weighted imaging of the prostate. Three-dimensional T2-weighted imaging could be used to considerably shorten prostate MRI protocols in clinical practice. • 3D shows equivalent image quality and lesion delineation compared to 2D T2w. • 3D T2w and 2D T2w image acquisition demonstrated comparable diagnostic performance. • Using a single 3D T2w acquisition may shorten the protocol by 40%. • Combined with short DCE, multiparametric protocols of 10 min are feasible.

Accounting for patient size in the optimization of dose and image quality of pelvis cone beam CT protocols on the Varian OBI system

PubMed Central

Moore, Craig S; Horsfield, Carl J; Saunderson, John R; Beavis, Andrew W

2015-01-01

Objective: The purpose of this study was to develop size-based radiotherapy kilovoltage cone beam CT (CBCT) protocols for the pelvis. Methods: Image noise was measured in an elliptical phantom of varying size for a range of exposure factors. Based on a previously defined “small pelvis” reference patient and CBCT protocol, appropriate exposure factors for small, medium, large and extra-large patients were derived which approximate the image noise behaviour observed on a Philips CT scanner (Philips Medical Systems, Best, Netherlands) with automatic exposure control (AEC). Selection criteria, based on maximum tube current–time product per rotation selected during the radiotherapy treatment planning scan, were derived based on an audit of patient size. Results: It has been demonstrated that 110 kVp yields acceptable image noise for reduced patient dose in pelvic CBCT scans of small, medium and large patients, when compared with manufacturer's default settings (125 kVp). Conversely, extra-large patients require increased exposure factors to give acceptable images. 57% of patients in the local population now receive much lower radiation doses, whereas 13% require higher doses (but now yield acceptable images). Conclusion: The implementation of size-based exposure protocols has significantly reduced radiation dose to the majority of patients with no negative impact on image quality. Increased doses are required on the largest patients to give adequate image quality. Advances in knowledge: The development of size-based CBCT protocols that use the planning CT scan (with AEC) to determine which protocol is appropriate ensures adequate image quality whilst minimizing patient radiation dose. PMID:26419892

Image guidance in prostate cancer - can offline corrections be an effective substitute for daily online imaging?

PubMed

Prasad, Devleena; Das, Pinaki; Saha, Niladri S; Chatterjee, Sanjoy; Achari, Rimpa; Mallick, Indranil

2014-01-01

This aim of this study was to determine if a less resource-intensive and established offline correction protocol - the No Action Level (NAL) protocol was as effective as daily online corrections of setup deviations in curative high-dose radiotherapy of prostate cancer. A total of 683 daily megavoltage CT (MVCT) or kilovoltage CT (kvCBCT) images of 30 patients with localized prostate cancer treated with intensity modulated radiotherapy were evaluated. Daily image-guidance was performed and setup errors in three translational axes recorded. The NAL protocol was simulated by using the mean shift calculated from the first five fractions and implemented on all subsequent treatments. Using the imaging data from the remaining fractions, the daily residual error (RE) was determined. The proportion of fractions where the RE was greater than 3,5 and 7 mm was calculated, and also the actual PTV margin that would be required if the offline protocol was followed. Using the NAL protocol reduced the systematic but not the random errors. Corrections made using the NAL protocol resulted in small and acceptable RE in the mediolateral (ML) and superoinferior (SI) directions with 46/533 (8.1%) and 48/533 (5%) residual shifts above 5 mm. However; residual errors greater than 5mm in the anteroposterior (AP) direction remained in 181/533 (34%) of fractions. The PTV margins calculated based on residual errors were 5mm, 5mm and 13 mm in the ML, SI and AP directions respectively. Offline correction using the NAL protocol resulted in unacceptably high residual errors in the AP direction, due to random uncertainties of rectal and bladder filling. Daily online imaging and corrections remain the standard image guidance policy for highly conformal radiotherapy of prostate cancer.

Ultralow dose dentomaxillofacial CT imaging and iterative reconstruction techniques: variability of Hounsfield units and contrast-to-noise ratio

PubMed Central

Bischel, Alexander; Stratis, Andreas; Kakar, Apoorv; Bosmans, Hilde; Jacobs, Reinhilde; Gassner, Eva-Maria; Puelacher, Wolfgang; Pauwels, Ruben

2016-01-01

Objective: The aim of this study was to evaluate whether application of ultralow dose protocols and iterative reconstruction technology (IRT) influence quantitative Hounsfield units (HUs) and contrast-to-noise ratio (CNR) in dentomaxillofacial CT imaging. Methods: A phantom with inserts of five types of materials was scanned using protocols for (a) a clinical reference for navigated surgery (CT dose index volume 36.58 mGy), (b) low-dose sinus imaging (18.28 mGy) and (c) four ultralow dose imaging (4.14, 2.63, 0.99 and 0.53 mGy). All images were reconstructed using: (i) filtered back projection (FBP); (ii) IRT: adaptive statistical iterative reconstruction-50 (ASIR-50), ASIR-100 and model-based iterative reconstruction (MBIR); and (iii) standard (std) and bone kernel. Mean HU, CNR and average HU error after recalibration were determined. Each combination of protocols was compared using Friedman analysis of variance, followed by Dunn's multiple comparison test. Results: Pearson's sample correlation coefficients were all >0.99. Ultralow dose protocols using FBP showed errors of up to 273 HU. Std kernels had less HU variability than bone kernels. MBIR reduced the error value for the lowest dose protocol to 138 HU and retained the highest relative CNR. ASIR could not demonstrate significant advantages over FBP. Conclusions: Considering a potential dose reduction as low as 1.5% of a std protocol, ultralow dose protocols and IRT should be further tested for clinical dentomaxillofacial CT imaging. Advances in knowledge: HU as a surrogate for bone density may vary significantly in CT ultralow dose imaging. However, use of std kernels and MBIR technology reduce HU error values and may retain the highest CNR. PMID:26859336

Synthesis of immunotargeted magneto-plasmonic nanoclusters.

PubMed

Wu, Chun-Hsien; Sokolov, Konstantin

2014-08-22

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications including contrast enhancement in novel magnetomotive imaging modalities, simultaneous capture and detection of circulating tumor cells (CTCs), and multimodal molecular imaging combined with photothermal therapy of cancer cells. These applications have stimulated significant interest in development of protocols for synthesis of magneto-plasmonic nanoparticles with optical absorbance in the near-infrared (NIR) region and a strong magnetic moment. Here, we present a novel protocol for synthesis of such hybrid nanoparticles that is based on an oil-in-water microemulsion method. The unique feature of the protocol described herein is synthesis of magneto-plasmonic nanoparticles of various sizes from primary blocks which also have magneto-plasmonic characteristics. This approach yields nanoparticles with a high density of magnetic and plasmonic functionalities which are uniformly distributed throughout the nanoparticle volume. The hybrid nanoparticles can be easily functionalized by attaching antibodies through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting.

High-intensity focused ultrasound (HIFU) array system for image-guided ablative therapy (IGAT)

NASA Astrophysics Data System (ADS)

Kaczkowski, Peter J.; Keilman, George W.; Cunitz, Bryan W.; Martin, Roy W.; Vaezy, Shahram; Crum, Lawrence A.

2003-06-01

Recent interest in using High Intensity Focused Ultrasound (HIFU) for surgical applications such as hemostasis and tissue necrosis has stimulated the development of image-guided systems for non-invasive HIFU therapy. Seeking an all-ultrasound therapeutic modality, we have developed a clinical HIFU system comprising an integrated applicator that permits precisely registered HIFU therapy delivery and high quality ultrasound imaging using two separate arrays, a multi-channel signal generator and RF amplifier system, and a software program that provides the clinician with a graphical overlay of the ultrasound image and therapeutic protocol controls. Electronic phasing of a 32 element 2 MHz HIFU annular array allows adjusting the focus within the range of about 4 to 12 cm from the face. A central opening in the HIFU transducer permits mounting a commercial medical imaging scanhead (ATL P7-4) that is held in place within a special housing. This mechanical fixture ensures precise coaxial registration between the HIFU transducer and the image plane of the imaging probe. Recent enhancements include development of an acoustic lens using numerical simulations for use with a 5-element array. Our image-guided therapy system is very flexible and enables exploration of a variety of new HIFU therapy delivery and monitoring approaches in the search for safe, effective, and efficient treatment protocols.

Secure Display of Space-Exploration Images

NASA Technical Reports Server (NTRS)

Cheng, Cecilia; Thornhill, Gillian; McAuley, Michael

2006-01-01

Java EDR Display Interface (JEDI) is software for either local display or secure Internet distribution, to authorized clients, of image data acquired from cameras aboard spacecraft engaged in exploration of remote planets. ( EDR signifies experimental data record, which, in effect, signifies image data.) Processed at NASA s Multimission Image Processing Laboratory (MIPL), the data can be from either near-realtime processing streams or stored files. JEDI uses the Java Advanced Imaging application program interface, plus input/output packages that are parts of the Video Image Communication and Retrieval software of the MIPL, to display images. JEDI can be run as either a standalone application program or within a Web browser as a servlet with an applet front end. In either operating mode, JEDI communicates using the HTTP(s) protocol(s). In the Web-browser case, the user must provide a password to gain access. For each user and/or image data type, there is a configuration file, called a "personality file," containing parameters that control the layout of the displays and the information to be included in them. Once JEDI has accepted the user s password, it processes the requested EDR (provided that user is authorized to receive the specific EDR) to create a display according to the user s personality file.

Consensus Recommendations of the Multiple Sclerosis Study Group and Portuguese Neuroradiological Society for the Use of the Magnetic Resonance Imaging in Multiple Sclerosis in Clinical Practice: Part 1.

PubMed

Abreu, Pedro; Pedrosa, Rui; Sá, Maria José; Cerqueira, João; Sousa, Lívia; Da Silva, Ana Martins; Pinheiro, Joaquim; De Sá, João; Batista, Sónia; Simões, Rita Moiron; Pereira, Daniela Jardim; Vilela, Pedro; Vale, José

2018-05-30

Magnetic resonance imaging is established as a recognizable tool in the diagnosis and monitoring of multiple sclerosis patients. In the present, among multiple sclerosis centers, there are different magnetic resonance imaging sequences and protocols used to study multiple sclerosis that may hamper the optimal use of magnetic resonance imaging in multiple sclerosis. In this context, the Group of Studies of Multiple Sclerosis and the Portuguese Society of Neuroradiology, after a joint discussion, appointed a committee of experts to create recommendations adapted to the national reality on the use of magnetic resonance imaging in multiple sclerosis. The purpose of this document is to publish the first Portuguese consensus recommendations on the use of magnetic resonance imaging in multiple sclerosis in clinical practice. The Group of Studies of Multiple Sclerosis and the Portuguese Society of Neuroradiology, after discussion of the topic in national meetings and after a working group meeting held in Figueira da Foz on May 2017, have appointed a committee of experts that have developed by consensus several standard protocols on the use of magnetic resonance imaging in the diagnosis and follow-up of multiple sclerosis. The document obtained was based on the best scientific evidence and expert opinion. Subsequently, the majority of Portuguese multiple sclerosis consultants and departments of neuroradiology scrutinized and reviewed the consensus paper; comments and suggestions were considered. Technical magnetic resonance imaging protocols regarding diagnostic, monitoring and the recommended information to be included in the magnetic resonance imaging report will be published in a separate paper. We provide some practical guidelines to promote standardized strategies to be applied in the clinical practice setting of Portuguese healthcare professionals regarding the use of magnetic resonance imaging in multiple sclerosis. We hope that these first Portuguese magnetic resonance imaging guidelines, based in the best available clinical evidence and practices, will serve to optimize multiple sclerosis management and improve multiple sclerosis patient care across Portugal.

Influence of basis images and skull position on evaluation of cortical bone thickness in cone beam computed tomography.

PubMed

Nascimento, Monikelly do Carmo Chagas; Boscolo, Solange Maria de Almeida; Haiter-Neto, Francisco; Santos, Emanuela Carla Dos; Lambrichts, Ivo; Pauwels, Ruben; Jacobs, Reinhilde

2017-06-01

The aim of this study was to assess the influence of the number of basis images and the orientation of the skull on the evaluation of cortical alveolar bone in cone beam computed tomography (CBCT). Eleven skulls with a total of 59 anterior teeth were selected. CBCT images were acquired by using 4 protocols, by varying the rotation of the tube-detector arm and the orientation of the skull (protocol 1: 360°/0°; protocol 2: 180°/0°; protocol 3: 180°/90°; protocol 4: 180°/180°). Observers evaluated cortical bone as absent, thin, or thick. Direct observation of the skulls was used as the gold standard. Intra- and interobserver agreement, as well as agreement of scoring between the 3 bone thickness classifications, were calculated by using the κ statistic. The Wilcoxon signed-rank test was used to compare the 4 protocols. For lingual cortical bone, protocol 1 showed no statistical difference from the gold standard. Higher reliability was found in protocol 3 for absent (κ = 0.80) and thin (κ = 0.47) cortices, whereas for thick cortical bone, protocol 2 was more consistent (κ = 0.60). In buccal cortical bone, protocol 1 obtained the highest agreement for absent cortices (κ = 0.61), whereas protocol 4 was better for thin cortical plates (κ = 0.38) and protocol 2 for thick cortical plates (κ = 0.40). No consistent effect of the number of basis images or head orientation for visual detection of alveolar bone was detected, except for lingual cortical bone, for which full rotation scanning showed improved visualization. Copyright © 2017 Elsevier Inc. All rights reserved.

Automatic image hanging protocol for chest radiographs in PACS.

PubMed

Luo, Hui; Hao, Wei; Foos, David H; Cornelius, Craig W

2006-04-01

Chest radiography is one of the most widely used techniques in diagnostic imaging. It comprises at least one-third of all diagnostic radiographic procedures in hospitals. However, in the picture archive and communication system, images are often stored with the projection and orientation unknown or mislabeled, which causes inefficiency for radiologists' interpretation. To address this problem, an automatic hanging protocol for chest radiographs is presented. The method targets the most effective region in a chest radiograph, and extracts a set of size-, rotation-, and translation-invariant features from it. Then, a well-trained classifier is used to recognize the projection. The orientation of the radiograph is later identified by locating the neck, heart, and abdomen positions in the radiographs. Initial experiments are performed on the radiographs collected from daily routine chest exams in hospitals and show promising results. Using the presented protocol, 98.2% of all cases could be hung correctly on projection view (without protocol, 62%), and 96.1% had correct orientation (without protocol, 75%). A workflow study on the protocol also demonstrates a significant improvement in efficiency for image display.

Multiphoton Intravital Calcium Imaging.

PubMed

Cheetham, Claire E J

2018-06-26

Multiphoton intravital calcium imaging is a powerful technique that enables high-resolution longitudinal monitoring of cellular and subcellular activity hundreds of microns deep in the living organism. This unit addresses the application of 2-photon microscopy to imaging of genetically encoded calcium indicators (GECIs) in the mouse brain. The protocols in this unit enable real-time intravital imaging of intracellular calcium concentration simultaneously in hundreds of neurons, or at the resolution of single synapses, as mice respond to sensory stimuli or perform behavioral tasks. Protocols are presented for implantation of a cranial imaging window to provide optical access to the brain and for 2-photon image acquisition. Protocols for implantation of both open skull and thinned skull windows for single or multi-session imaging are described. © 2018 by John Wiley & Sons, Inc. © 2018 John Wiley & Sons, Inc.

WE-G-19A-01: Radiologists and Medical Physicists: Working Together to Achieve Common Goals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, A; Ma, J; Steele, J

It is vitally important that medical physicists understand the clinical questions that radiologists are trying to answer with patient images. Knowledge of the types of information the radiologist needs helps medical physicists configure imaging protocols that appropriately balance radiation dose, time, and image quality. The ability to communicate with radiologists and understand medical terminology, anatomy, and physiology is key to creating such imaging protocols. In this session, radiologists will present clinical cases and describe the information they are seeking in the clinical images. Medical physicists will then discuss how imaging protocols are configured. Learning Objectives: Understand the types of informationmore » that radiologists seek in medical images. Apply this understanding in configuring the imaging equipment to deliver this information. Develop strategies for working with physician colleagues.« less

An improved protocol for optical projection tomography imaging reveals lobular heterogeneities in pancreatic islet and β-cell mass distribution

PubMed Central

2011-01-01

Optical projection tomography (OPT) imaging is a powerful tool for three-dimensional imaging of gene and protein distribution patterns in biomedical specimens. We have previously demonstrated the possibility, by this technique, to extract information of the spatial and quantitative distribution of the islets of Langerhans in the intact mouse pancreas. In order to further increase the sensitivity of OPT imaging for this type of assessment, we have developed a protocol implementing a computational statistical approach: contrast limited adaptive histogram equalization (CLAHE). We demonstrate that this protocol significantly increases the sensitivity of OPT imaging for islet detection, helps preserve islet morphology and diminish subjectivity in thresholding for tomographic reconstruction. When applied to studies of the pancreas from healthy C57BL/6 mice, our data reveal that, at least in this strain, the pancreas harbors substantially more islets than has previously been reported. Further, we provide evidence that the gastric, duodenal and splenic lobes of the pancreas display dramatic differences in total and relative islet and β-cell mass distribution. This includes a 75% higher islet density in the gastric lobe as compared to the splenic lobe and a higher relative volume of insulin producing cells in the duodenal lobe as compared to the other lobes. Altogether, our data show that CLAHE substantially improves OPT based assessments of the islets of Langerhans and that lobular origin must be taken into careful consideration in quantitative and spatial assessments of the pancreas. PMID:21633198

Adaptive Quantification and Longitudinal Analysis of Pulmonary Emphysema with a Hidden Markov Measure Field Model

PubMed Central

Häme, Yrjö; Angelini, Elsa D.; Hoffman, Eric A.; Barr, R. Graham; Laine, Andrew F.

2014-01-01

The extent of pulmonary emphysema is commonly estimated from CT images by computing the proportional area of voxels below a predefined attenuation threshold. However, the reliability of this approach is limited by several factors that affect the CT intensity distributions in the lung. This work presents a novel method for emphysema quantification, based on parametric modeling of intensity distributions in the lung and a hidden Markov measure field model to segment emphysematous regions. The framework adapts to the characteristics of an image to ensure a robust quantification of emphysema under varying CT imaging protocols and differences in parenchymal intensity distributions due to factors such as inspiration level. Compared to standard approaches, the present model involves a larger number of parameters, most of which can be estimated from data, to handle the variability encountered in lung CT scans. The method was used to quantify emphysema on a cohort of 87 subjects, with repeated CT scans acquired over a time period of 8 years using different imaging protocols. The scans were acquired approximately annually, and the data set included a total of 365 scans. The results show that the emphysema estimates produced by the proposed method have very high intra-subject correlation values. By reducing sensitivity to changes in imaging protocol, the method provides a more robust estimate than standard approaches. In addition, the generated emphysema delineations promise great advantages for regional analysis of emphysema extent and progression, possibly advancing disease subtyping. PMID:24759984

Advances in Imaging and Management Trends of Traumatic Aortic Injuries.

PubMed

Nagpal, Prashant; Mullan, Brian F; Sen, Indrani; Saboo, Sachin S; Khandelwal, Ashish

2017-05-01

Acute traumatic aortic injury (ATAI) is a life-threatening injury. CT is the imaging tool of choice, and the knowledge of direct and indirect signs of injury, grading system, and current management protocol helps the emergency radiologist to better identify and classify the injury and provide additional details that can impact management options. Newer dual-source CT technology with ultrafast acquisition speed has also influenced the appropriate protocol for imaging in patients with suspected ATAI. This review highlights the imaging protocol in patients with blunt trauma, CT appearance and grading systems of ATAI, management options, and the role of the multidisciplinary team in the management of these patients. We also briefly review the current literature on the definition, treatment, and follow-up protocol in patients with minimal aortic injury.

Management of paediatric periorbital cellulitis: Our experience of 243 children managed according to a standardised protocol 2012-2015.

PubMed

Crosbie, Robin A; Nairn, Jonathan; Kubba, Haytham

2016-08-01

Paediatric periorbital cellulitis is a common condition. Accurate assessment can be challenging and appropriate use of CT imaging is essential. We audited admissions to our unit over a four year period, with reference to CT scanning and adherence to our protocol. Retrospective audit of paediatric patients admitted with periorbital cellulitis, 2012-2015. Total of 243 patients included, mean age 4.7 years with slight male predominance, the median length of admission was 2 days. 48/243 (20%) underwent CT during admission, 25 (52%) of these underwent surgical drainage. As per protocol, CT brain performed with all orbital scans; no positive intracranial findings on any initial scan. Three children developed intracranial complications subsequently; all treated with antibiotics. Our re-admission rate within 30 days was 2.5%. Our audit demonstrates benefit of standardising practice and the low CT rate, with high percentage taken to theatre and no missed abscesses, supports the protocol. There may be an argument to avoid CT brain routinely in all initial imaging sequences in those children without neurological signs or symptoms. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Angle and Base of Gait Long Leg Axial and Intraoperative Simulated Weightbearing Long Leg Axial Imaging to Capture True Frontal Plane Tibia to Calcaneus Alignment in Valgus and Varus Deformities of the Rearfoot and Ankle.

PubMed

Boffeli, Troy J; Waverly, Brett J

2016-01-01

The long leg axial view is primarily used to evaluate the frontal plane alignment of the calcaneus in relation to the long axis of the tibia when standing. This view allows both angular measurement and assessment for the apex of varus and valgus deformity of the rearfoot and ankle with clinical utility in the preoperative, intraoperative, and postoperative settings. The frontal plane alignment of the calcaneus to the long axis of the tibia is rarely fixed in the varus or valgus position because of the inherent flexibility of the foot and ankle, which makes patient positioning critical to obtain accurate and reproducible images. Inconsistent patient positioning and imaging techniques are commonly encountered with the long leg axial view for a variety of reasons, including the lack of a standardized or validated protocol. This angle and base of gait imaging protocol involves positioning the patient to align the tibia with the long axis of the foot, which is represented by the second metatarsal. Non-weightbearing long leg axial imaging is commonly performed intraoperatively, which requires a modified patient positioning technique to capture simulated weightbearing long leg axial images. A case series is presented to demonstrate our angle and base of gait long leg axial and intraoperative simulated weightbearing long leg axial imaging protocols that can be applied throughout all phases of patient care for various foot and ankle conditions. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

80-kVp CT Using Iterative Reconstruction in Image Space Algorithm for the Detection of Hypervascular Hepatocellular Carcinoma: Phantom and Initial Clinical Experience

PubMed Central

Hur, Saebeom; Kim, Soo Jin; Park, Ji Hoon; Han, Joon Koo; Choi, Byung Ihn

2012-01-01

Objective To investigate whether the low-tube-voltage (80-kVp), intermediate-tube-current (340-mAs) MDCT using the Iterative Reconstruction in Image Space (IRIS) algorithm improves lesion-to-liver contrast at reduced radiation dosage while maintaining acceptable image noise in the detection of hepatocellular carcinomas (HCC) in thin (mean body mass index, 24 ± 0.4 kg/m2) adults. Subjects and Methods A phantom simulating the liver with HCC was scanned at 50-400 mAs for 80, 100, 120 and 140-kVp. In addition, fifty patients with HCC who underwent multiphasic liver CT using dual-energy (80-kVp and 140-kVp) arterial scans were enrolled. Virtual 120-kVP scans (protocol A) and 80-kVp scans (protocol B) of the late arterial phase were reconstructed with filtered back-projection (FBP), while corresponding 80-kVp scans were reconstructed with IRIS (protocol C). Contrast-to-noise ratio (CNR) of HCCs and abdominal organs were assessed quantitatively, whereas lesion conspicuity, image noise, and overall image quality were assessed qualitatively. Results IRIS effectively reduced image noise, and yielded 29% higher CNR than the FBP at equivalent tube voltage and current in the phantom study. In the quantitative patient study, protocol C helped improve CNR by 51% and 172% than protocols A and B (p < 0.001), respectively, at equivalent radiation dosage. In the qualitative study, protocol C acquired the highest score for lesion conspicuity albeit with an inferior score to protocol A for overall image quality (p < 0.001). Mean effective dose was 2.63-mSv with protocol A and 1.12-mSv with protocols B and C. Conclusion CT using the low-tube-voltage, intermediate-tube-current and IRIS help improve lesion-to-liver CNR of HCC in thin adults during the arterial phase at a lower radiation dose when compared with the standard technique using 120-kVp and FBP. PMID:22438682

Multi-site Study of Diffusion Metric Variability: Characterizing the Effects of Site, Vendor, Field Strength, and Echo Time using the Histogram Distance

PubMed Central

Helmer, K. G.; Chou, M-C.; Preciado, R. I.; Gimi, B.; Rollins, N. K.; Song, A.; Turner, J.; Mori, S.

2016-01-01

MRI-based multi-site trials now routinely include some form of diffusion-weighted imaging (DWI) in their protocol. These studies can include data originating from scanners built by different vendors, each with their own set of unique protocol restrictions, including restrictions on the number of available gradient directions, whether an externally-generated list of gradient directions can be used, and restrictions on the echo time (TE). One challenge of multi-site studies is to create a common imaging protocol that will result in a reliable and accurate set of diffusion metrics. The present study describes the effect of site, scanner vendor, field strength, and TE on two common metrics: the first moment of the diffusion tensor field (mean diffusivity, MD), and the fractional anisotropy (FA). We have shown in earlier work that ROI metrics and the mean of MD and FA histograms are not sufficiently sensitive for use in site characterization. Here we use the distance between whole brain histograms of FA and MD to investigate within- and between-site effects. We concluded that the variability of DTI metrics due to site, vendor, field strength, and echo time could influence the results in multi-center trials and that histogram distance is sensitive metrics for each of these variables. PMID:27350723

Improving cerebellar segmentation with statistical fusion

NASA Astrophysics Data System (ADS)

Plassard, Andrew J.; Yang, Zhen; Prince, Jerry L.; Claassen, Daniel O.; Landman, Bennett A.

2016-03-01

The cerebellum is a somatotopically organized central component of the central nervous system well known to be involved with motor coordination and increasingly recognized roles in cognition and planning. Recent work in multiatlas labeling has created methods that offer the potential for fully automated 3-D parcellation of the cerebellar lobules and vermis (which are organizationally equivalent to cortical gray matter areas). This work explores the trade offs of using different statistical fusion techniques and post hoc optimizations in two datasets with distinct imaging protocols. We offer a novel fusion technique by extending the ideas of the Selective and Iterative Method for Performance Level Estimation (SIMPLE) to a patch-based performance model. We demonstrate the effectiveness of our algorithm, Non- Local SIMPLE, for segmentation of a mixed population of healthy subjects and patients with severe cerebellar anatomy. Under the first imaging protocol, we show that Non-Local SIMPLE outperforms previous gold-standard segmentation techniques. In the second imaging protocol, we show that Non-Local SIMPLE outperforms previous gold standard techniques but is outperformed by a non-locally weighted vote with the deeper population of atlases available. This work advances the state of the art in open source cerebellar segmentation algorithms and offers the opportunity for routinely including cerebellar segmentation in magnetic resonance imaging studies that acquire whole brain T1-weighted volumes with approximately 1 mm isotropic resolution.

A highly sensitive protocol for microscopy of alkyne lipids and fluorescently tagged or immunostained proteins.

PubMed

Gaebler, Anne; Penno, Anke; Kuerschner, Lars; Thiele, Christoph

2016-10-01

The demand to study the cellular localization of specific lipids has led to recent advances in lipid probes and microscopy. Alkyne lipids bear a small, noninterfering tag and can be detected upon click reaction with an azide-coupled reporter. Fluorescent alkyne lipid imaging crucially depends on appropriate azide reporters and labeling protocols that allow for an efficient click reaction and therefore a sensitive detection. We synthesized several azide reporters with different spacer components and tested their suitability for alkyne lipid imaging in fixed cells. The implementation of a copper-chelating picolyl moiety into fluorescent or biotin-based azide reagents strongly increased the sensitivity of the imaging routine. We demonstrate the applicability and evaluate the performance of this approach using different lipid classes and experimental setups. As azide picolyl reporters allow for reduced copper catalyst concentrations, they also enable coimaging of alkyne lipids with multiple fluorescent proteins including enhanced green fluorescent protein. Alternatively, and as we also show, microscopy of alkyne lipids can be combined with protein detection by immunocytochemistry. In summary, we present a robust, sensitive, and highly versatile protocol for the labeling of alkyne lipids with azide-coupled reporters for fluorescence microscopy that can be combined with different protein detection and imaging techniques. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

Biplane interventional pediatric system with cone‐beam CT: dose and image quality characterization for the default protocols

PubMed Central

Vañó, Eliseo; Alejo, Luis; Ubeda, Carlos; Gutiérrez‐Larraya, Federico; Garayoa, Julia

2016-01-01

The aim of this study was to assess image quality and radiation dose of a biplane angiographic system with cone‐beam CT (CBCT) capability tuned for pediatric cardiac procedures. The results of this study can be used to explore dose reduction techniques. For pulsed fluoroscopy and cine modes, polymethyl methacrylate phantoms of various thicknesses and a Leeds TOR 18‐FG test object were employed. Various fields of view (FOV) were selected. For CBCT, the study employed head and body dose phantoms, Catphan 504, and an anthropomorphic cardiology phantom. The study also compared two 3D rotational angiography protocols. The entrance surface air kerma per frame increases by a factor of 3–12 when comparing cine and fluoroscopy frames. The biggest difference in the signal‐to‐noise ratio between fluoroscopy and cine modes occurs at FOV 32 cm because fluoroscopy is acquired at a 1440×1440 pixel matrix size and in unbinned mode, whereas cine is acquired at 720×720 pixels and in binned mode. The high‐contrast spatial resolution of cine is better than that of fluoroscopy, except for FOV 32 cm, because fluoroscopy mode with 32 cm FOV is unbinned. Acquiring CBCT series with a 16 cm head phantom using the standard dose protocol results in a threefold dose increase compared with the low‐dose protocol. Although the amount of noise present in the images acquired with the low‐dose protocol is much higher than that obtained with the standard mode, the images present better spatial resolution. A 1 mm diameter rod with 250 Hounsfield units can be distinguished in reconstructed images with an 8 mm slice width. Pediatric‐specific protocols provide lower doses while maintaining sufficient image quality. The system offers a novel 3D imaging mode. The acquisition of CBCT images results in increased doses administered to the patients, but also provides further diagnostic information contained in the volumetric images. The assessed CBCT protocols provide images that are noisy, but with very good spatial resolution. PACS number(s): 87.59.‐e, 87.59.‐C, 87.59.‐cf, 87.59.Dj, 87.57. uq PMID:27455474

Biplane interventional pediatric system with cone-beam CT: dose and image quality characterization for the default protocols.

PubMed

Corredoira, Eva; Vañó, Eliseo; Alejo, Luis; Ubeda, Carlos; Gutiérrez-Larraya, Federico; Garayoa, Julia

2016-07-08

The aim of this study was to assess image quality and radiation dose of a biplane angiographic system with cone-beam CT (CBCT) capability tuned for pediatric cardiac procedures. The results of this study can be used to explore dose reduction techniques. For pulsed fluoroscopy and cine modes, polymethyl methacrylate phantoms of various thicknesses and a Leeds TOR 18-FG test object were employed. Various fields of view (FOV) were selected. For CBCT, the study employed head and body dose phantoms, Catphan 504, and an anthropomorphic cardiology phantom. The study also compared two 3D rotational angiography protocols. The entrance surface air kerma per frame increases by a factor of 3-12 when comparing cine and fluoroscopy frames. The biggest difference in the signal-to- noise ratio between fluoroscopy and cine modes occurs at FOV 32 cm because fluoroscopy is acquired at a 1440 × 1440 pixel matrix size and in unbinned mode, whereas cine is acquired at 720 × 720 pixels and in binned mode. The high-contrast spatial resolution of cine is better than that of fluoroscopy, except for FOV 32 cm, because fluoroscopy mode with 32 cm FOV is unbinned. Acquiring CBCT series with a 16 cm head phantom using the standard dose protocol results in a threefold dose increase compared with the low-dose protocol. Although the amount of noise present in the images acquired with the low-dose protocol is much higher than that obtained with the standard mode, the images present better spatial resolution. A 1 mm diameter rod with 250 Hounsfield units can be distinguished in reconstructed images with an 8 mm slice width. Pediatric-specific protocols provide lower doses while maintaining sufficient image quality. The system offers a novel 3D imaging mode. The acquisition of CBCT images results in increased doses administered to the patients, but also provides further diagnostic information contained in the volumetric images. The assessed CBCT protocols provide images that are noisy, but with very good spatial resolution. © 2016 The Authors.

Quantum image processing: A review of advances in its security technologies

NASA Astrophysics Data System (ADS)

Yan, Fei; Iliyasu, Abdullah M.; Le, Phuc Q.

In this review, we present an overview of the advances made in quantum image processing (QIP) comprising of the image representations, the operations realizable on them, and the likely protocols and algorithms for their applications. In particular, we focus on recent progresses on QIP-based security technologies including quantum watermarking, quantum image encryption, and quantum image steganography. This review is aimed at providing readers with a succinct, yet adequate compendium of the progresses made in the QIP sub-area. Hopefully, this effort will stimulate further interest aimed at the pursuit of more advanced algorithms and experimental validations for available technologies and extensions to other domains.

Review of cardiovascular imaging in the Journal of Nuclear Cardiology in 2017. Part 2 of 2: Myocardial perfusion imaging.

PubMed

Hage, Fadi G; AlJaroudi, Wael A

2018-04-16

In 2017, the Journal of Nuclear Cardiology published many high-quality articles. In this review, we will summarize a selection of these articles to provide a concise review of the main advancements that have recently occurred in the field. In the first article of this 2-part series, we focused on publications dealing with positron emission tomography, computed tomography, and magnetic resonance. This review will place emphasis on myocardial perfusion imaging using single-photon emission computed tomography summarizing advances in the field including prognosis, safety and tolerability, the impact of imaging on management, and the use of novel imaging protocols.

New and emerging patient-centered CT imaging and image-guided treatment paradigms for maxillofacial trauma.

PubMed

Dreizin, David; Nam, Arthur J; Hirsch, Jeffrey; Bernstein, Mark P

2018-06-20

This article reviews the conceptual framework, available evidence, and practical considerations pertaining to nascent and emerging advances in patient-centered CT-imaging and CT-guided surgery for maxillofacial trauma. These include cinematic rendering-a novel method for advanced 3D visualization, incorporation of quantitative CT imaging into the assessment of orbital fractures, low-dose CT imaging protocols made possible with contemporary scanners and reconstruction techniques, the rapidly growing use of cone-beam CT, virtual fracture reduction with design software for surgical pre-planning, the use of 3D printing for fabricating models and implants, and new avenues in CT-guided computer-aided surgery.

Intravital multiphoton imaging of mouse tibialis anterior muscle

PubMed Central

Lau, Jasmine; Goh, Chi Ching; Devi, Sapna; Keeble, Jo; See, Peter; Ginhoux, Florent; Ng, Lai Guan

2016-01-01

ABSTRACT Intravital imaging by multiphoton microscopy is a powerful tool to gain invaluable insight into tissue biology and function. Here, we provide a step-by-step tissue preparation protocol for imaging the mouse tibialis anterior skeletal muscle. Additionally, we include steps for jugular vein catheterization that allow for well-controlled intravenous reagent delivery. Preparation of the tibialis anterior muscle is minimally invasive, reducing the chances of inducing damage and inflammation prior to imaging. The tibialis anterior muscle is useful for imaging leukocyte interaction with vascular endothelium, and to understand muscle contraction biology. Importantly, this model can be easily adapted to study neuromuscular diseases and myopathies. PMID:28243520

A customized protocol to assess bone quality in the metacarpal head, metacarpal shaft and distal radius: a high resolution peripheral quantitative computed tomography precision study.

PubMed

Feehan, Lynne; Buie, Helen; Li, Linda; McKay, Heather

2013-12-24

High Resolution-Peripheral Quantitative Computed Tomography (HR-pQCT) is an emerging technology for evaluation of bone quality in Rheumatoid Arthritis (RA). However, there are limitations with standard HR-pQCT imaging protocols for examination of regions of bone commonly affected in RA. We developed a customized protocol for evaluation of volumetric bone mineral density (vBMD) and microstructure at the metacarpal head (MH), metacarpal shaft (MS) and ultra-ultra-distal (UUD) radius; three sites commonly affected in RA. The purpose was to evaluate short-term measurement precision for bone density and microstructure at these sites. 12 non-RA participants, individuals likely to have no pre-existing bone damage, consented to participate [8 females, aged 23 to 71 y [median (IQR): 44 (28) y]. The custom protocol includes more comfortable/stable positioning and adapted cortical segmentation and direct transformation analysis methods. Dominant arm MH, MS and UUD radius scans were completed on day one; repeated twice (with repositioning) three to seven days later. Short-term precision for repeated measures was explored using intraclass correlational coefficient (ICC), mean coefficient of variation (CV%), root mean square coefficient of variation (RMSCV%) and least significant change (LSC%95). Bone density and microstructure precision was excellent: ICCs varied from 0.88 (MH2 trabecular number) to .99 (MS3 polar moment of inertia); CV% varied from < 1 (MS2 vBMD) to 6 (MS3 marrow space diameter); RMSCV% varied from < 1 (MH2 full bone vBMD) to 7 (MS3 marrow space diameter); and LSC%95 varied from 2 (MS2 full bone vBMD to 21 (MS3 marrow space diameter). Cortical porosity measures were the exception; RMSCV% varying from 19 (MS3) to 42 (UUD). No scans were stopped for discomfort. 5% (5/104) were repeated due to motion during imaging. 8% (8/104) of final images had motion artifact graded > 3 on 5 point scale. In our facility, this custom protocol extends the potential for in vivo HR-pQCT imaging to assess, with high precision, regional differences in bone quality at three sites commonly affected in RA. Our methods are easy to adopt and we recommend other users of HR-pQCT consider this protocol for further evaluations of its precision and feasibility in their imaging facilities.

Cerebral bone subtraction CT angiography using 80 kVp and sinogram-affirmed iterative reconstruction: contrast medium and radiation dose reduction with improvement of image quality.

PubMed

Nagayama, Yasunori; Nakaura, Takeshi; Tsuji, Akinori; Urata, Joji; Furusawa, Mitsuhiro; Yuki, Hideaki; Hirarta, Kenichiro; Oda, Seitaro; Kidoh, Masafumi; Utsunomiya, Daisuke; Yamashita, Yasuyuki

2017-02-01

The purpose of this study was to evaluate the feasibility of a contrast medium (CM), radiation dose reduction protocol for cerebral bone-subtraction CT angiography (BSCTA) using 80-kVp and sinogram-affirmed iterative reconstruction (SAFIRE). Seventy-five patients who had undergone BSCTA under the 120- (n = 37) or the 80-kVp protocol (n = 38) were included. CM was 370 mgI/kg for the 120-kVp and 296 mgI/kg for the 80-kVp protocol; the 120- and the 80-kVp images were reconstructed with filtered back-projection (FBP) and SAFIRE, respectively. We compared effective dose (ED), CT attenuation, image noise, and contrast-to-noise ratio (CNR) of two protocols. We also scored arterial contrast, sharpness, depiction of small arteries, visibility near skull base/clip, and overall image quality on a four-point scale. ED was 62% lower at 80- than 120-kVp (0.59 ± 0.06 vs 1.56 ± 0.13 mSv, p < 0.01). CT attenuation of the internal carotid artery (ICA) and middle cerebral artery (MCA) was significantly higher on 80- than 120-kVp (ICA: 557.4 ± 105.7 vs 370.0 ± 59.3 Hounsfield units (HU), p < 0.01; MCA: 551.9 ± 107.9 vs 364.6 ± 62.2 HU, p < 0.01). The CNR was also significantly higher on 80- than 120-kVp (ICA: 46.2 ± 10.2 vs 36.9 ± 7.6, p < 0.01; MCA: 45.7 ± 10.0 vs 35.7 ± 9.0, p < 0.01). Visibility near skull base and clip was not significantly different (p = 0.45). The other subjective scores were higher with the 80- than the 120-kVp protocol (p < 0.05). The 80-kVp acquisition with SAFIRE yields better image quality for BSCTA and substantial reduction in the radiation and CM dose compared to the 120-kVp with FBP protocol.

Phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography

PubMed Central

Ludlow, John B.; Walker, Cameron

2013-01-01

Introduction Increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern with the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. Methods Effective doses resulting from various combinations of field size, and field location comparing child and adult anthropomorphic phantoms using the recently introduced i-CAT FLX cone-beam computed tomography unit were measured with Optical Stimulated Dosimetry using previously validated protocols. Scan protocols included High Resolution (360° rotation, 600 image frames, 120 kVp, 5 mA, 7.4 sec), Standard (360°, 300 frames, 120 kVp, 5 mA, 3.7 sec), QuickScan (180°, 160 frames, 120 kVp, 5 mA, 2 sec) and QuickScan+ (180°, 160 frames, 90 kVp, 3 mA, 2 sec). Contrast-to-noise ratio (CNR) was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. Results Child phantom doses were on average 36% greater than Adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than Standard protocols for child (p=0.0167) and adult (p=0.0055) phantoms. 13×16 cm cephalometric fields of view ranged from 11–85 μSv in the adult phantom and 18–120 μSv in the child for QuickScan+ and Standard protocols respectively. CNR was reduced by approximately 2/3rds comparing QuickScan+ to Standard exposure parameters. Conclusions QuickScan+ effective doses are comparable to conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off may be acceptable for certain diagnostic tasks such as interim assessment of treatment results. PMID:24286904

Effect of automated tube voltage selection, integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of 3rd generation dual-source aortic CT angiography: An intra-individual comparison.

PubMed

Mangold, Stefanie; De Cecco, Carlo N; Wichmann, Julian L; Canstein, Christian; Varga-Szemes, Akos; Caruso, Damiano; Fuller, Stephen R; Bamberg, Fabian; Nikolaou, Konstantin; Schoepf, U Joseph

2016-05-01

To compare, on an intra-individual basis, the effect of automated tube voltage selection (ATVS), integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of aortic CTA studies using 2nd and 3rd generation dual-source CT (DSCT). We retrospectively evaluated 32 patients who had undergone CTA of the entire aorta with both 2nd generation DSCT at 120kV using filtered back projection (FBP) (protocol 1) and 3rd generation DSCT using ATVS, an integrated circuit detector and advanced iterative reconstruction (protocol 2). Contrast-to-noise ratio (CNR) was calculated. Image quality was subjectively evaluated using a five-point scale. Radiation dose parameters were recorded. All studies were considered of diagnostic image quality. CNR was significantly higher with protocol 2 (15.0±5.2 vs 11.0±4.2; p<.0001). Subjective image quality analysis revealed no significant differences for evaluation of attenuation (p=0.08501) but image noise was rated significantly lower with protocol 2 (p=0.0005). Mean tube voltage and effective dose were 94.7±14.1kV and 6.7±3.9mSv with protocol 2; 120±0kV and 11.5±5.2mSv with protocol 1 (p<0.0001, respectively). Aortic CTA performed with 3rd generation DSCT, ATVS, integrated circuit detector, and advanced iterative reconstruction allow a substantial reduction of radiation exposure while improving image quality in comparison to 120kV imaging with FBP. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dedicated dental volumetric and total body multislice computed tomography: a comparison of image quality and radiation dose

NASA Astrophysics Data System (ADS)

Strocchi, Sabina; Colli, Vittoria; Novario, Raffaele; Carrafiello, Gianpaolo; Giorgianni, Andrea; Macchi, Aldo; Fugazzola, Carlo; Conte, Leopoldo

2007-03-01

Aim of this work is to compare the performances of a Xoran Technologies i-CAT Cone Beam CT for dental applications with those of a standard total body multislice CT (Toshiba Aquilion 64 multislice) used for dental examinations. Image quality and doses to patients have been compared for the three main i-CAT protocols, the Toshiba standard protocol and a Toshiba modified protocol. Images of two phantoms have been acquired: a standard CT quality control phantom and an Alderson Rando ® anthropomorphic phantom. Image noise, Signal to Noise Ratio (SNR), Contrast to Noise Ratio (CNR) and geometric accuracy have been considered. Clinical image quality was assessed. Effective dose and doses to main head and neck organs were evaluated by means of thermo-luminescent dosimeters (TLD-100) placed in the anthropomorphic phantom. A Quality Index (QI), defined as the ratio of squared CNR to effective dose, has been evaluated. The evaluated effective doses range from 0.06 mSv (i-CAT 10 s protocol) to 2.37 mSv (Toshiba standard protocol). The Toshiba modified protocol (halved tube current, higher pitch value) imparts lower effective dose (0.99 mSv). The conventional CT device provides lower image noise and better SNR, but clinical effectiveness similar to that of dedicated dental CT (comparable CNR and clinical judgment). Consequently, QI values are much higher for this second CT scanner. No geometric distortion has been observed with both devices. As a conclusion, dental volumetric CT supplies adequate image quality to clinical purposes, at doses that are really lower than those imparted by a conventional CT device.

Evaluation of the articular cartilage of the knee joint: value of adding a T2 mapping sequence to a routine MR imaging protocol.

PubMed

Kijowski, Richard; Blankenbaker, Donna G; Munoz Del Rio, Alejandro; Baer, Geoffrey S; Graf, Ben K

2013-05-01

To determine whether the addition of a T2 mapping sequence to a routine magnetic resonance (MR) imaging protocol could improve diagnostic performance in the detection of surgically confirmed cartilage lesions within the knee joint at 3.0 T. This prospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. The study group consisted of 150 patients (76 male and 74 female patients with an average age of 41.2 and 41.5 years, respectively) who underwent MR imaging and arthroscopy of the knee joint. MR imaging was performed at 3.0 T by using a routine protocol with the addition of a sagittal T2 mapping sequence. Images from all MR examinations were reviewed in consensus by two radiologists before surgery to determine the presence or absence of cartilage lesions on each articular surface, first by using the routine MR protocol alone and then by using the routine MR protocol with T2 maps. Each articular surface was then evaluated at arthroscopy. Generalized estimating equation models were used to compare the sensitivity and specificity of the routine MR imaging protocol with and without T2 maps in the detection of surgically confirmed cartilage lesions. The sensitivity and specificity in the detection of 351 cartilage lesions were 74.6% and 97.8%, respectively, for the routine MR protocol alone and 88.9% and 93.1% for the routine MR protocol with T2 maps. Differences in sensitivity and specificity were statistically significant (P < .001). The addition of T2 maps to the routine MR imaging protocol significantly improved the sensitivity in the detection of 24 areas of cartilage softening (from 4.2% to 62%, P < .001), 41 areas of cartilage fibrillation (from 20% to 66%, P < .001), and 96 superficial partial-thickness cartilage defects (from 71% to 88%, P = .004). The addition of a T2 mapping sequence to a routine MR protocol at 3.0 T improved sensitivity in the detection of cartilage lesions within the knee joint from 74.6% to 88.9%, with only a small reduction in specificity. The greatest improvement in sensitivity with use of the T2 maps was in the identification of early cartilage degeneration. © RSNA, 2013.

Preparation of a Trp-BODIPY fluorogenic amino acid to label peptides for enhanced live-cell fluorescence imaging.

PubMed

Mendive-Tapia, Lorena; Subiros-Funosas, Ramon; Zhao, Can; Albericio, Fernando; Read, Nick D; Lavilla, Rodolfo; Vendrell, Marc

2017-08-01

Fluorescent peptides are valuable tools for live-cell imaging because of the high specificity of peptide sequences for their biomolecular targets. When preparing fluorescent versions of peptides, labels must be introduced at appropriate positions in the sequences to provide suitable reporters while avoiding any impairment of the molecular recognition properties of the peptides. This protocol describes the preparation of the tryptophan (Trp)-based fluorogenic amino acid Fmoc-Trp(C 2 -BODIPY)-OH and its incorporation into peptides for live-cell fluorescence imaging-an approach that is applicable to most peptide sequences. Fmoc-Trp(C 2 -BODIPY)-OH contains a BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) fluorogenic core, which works as an environmentally sensitive fluorophore, showing high fluorescence in lipophilic conditions. It is attached to Trp via a spacer-free C-C linkage, resulting in a labeled amino acid that can mimic the molecular interactions of Trp, enabling wash-free imaging. This protocol covers the chemical synthesis of the fluorogenic amino acid Fmoc-Trp(C 2 -BODIPY)-OH (3-4 d), the preparation of the labeled antimicrobial peptide BODIPY-cPAF26 by solid-phase synthesis (6-7 d) and its spectral and biological characterization as a live-cell imaging probe for different fungal pathogens. As an example, we include a procedure for using BODIPY-cPAF26 for wash-free imaging of fungal pathogens, including real-time visualization of Aspergillus fumigatus (5 d for culturing, 1-2 d for imaging).

The multiple sclerosis visual pathway cohort: understanding neurodegeneration in MS.

PubMed

Martínez-Lapiscina, Elena H; Fraga-Pumar, Elena; Gabilondo, Iñigo; Martínez-Heras, Eloy; Torres-Torres, Ruben; Ortiz-Pérez, Santiago; Llufriu, Sara; Tercero, Ana; Andorra, Magi; Roca, Marc Figueras; Lampert, Erika; Zubizarreta, Irati; Saiz, Albert; Sanchez-Dalmau, Bernardo; Villoslada, Pablo

2014-12-15

Multiple Sclerosis (MS) is an immune-mediated disease of the Central Nervous System with two major underlying etiopathogenic processes: inflammation and neurodegeneration. The latter determines the prognosis of this disease. MS is the main cause of non-traumatic disability in middle-aged populations. The MS-VisualPath Cohort was set up to study the neurodegenerative component of MS using advanced imaging techniques by focusing on analysis of the visual pathway in a middle-aged MS population in Barcelona, Spain. We started the recruitment of patients in the early phase of MS in 2010 and it remains permanently open. All patients undergo a complete neurological and ophthalmological examination including measurements of physical and disability (Expanded Disability Status Scale; Multiple Sclerosis Functional Composite and neuropsychological tests), disease activity (relapses) and visual function testing (visual acuity, color vision and visual field). The MS-VisualPath protocol also assesses the presence of anxiety and depressive symptoms (Hospital Anxiety and Depression Scale), general quality of life (SF-36) and visual quality of life (25-Item National Eye Institute Visual Function Questionnaire with the 10-Item Neuro-Ophthalmic Supplement). In addition, the imaging protocol includes both retinal (Optical Coherence Tomography and Wide-Field Fundus Imaging) and brain imaging (Magnetic Resonance Imaging). Finally, multifocal Visual Evoked Potentials are used to perform neurophysiological assessment of the visual pathway. The analysis of the visual pathway with advance imaging and electrophysilogical tools in parallel with clinical information will provide significant and new knowledge regarding neurodegeneration in MS and provide new clinical and imaging biomarkers to help monitor disease progression in these patients.

Assessment of phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography.

PubMed

Ludlow, John B; Walker, Cameron

2013-12-01

The increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern about the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. Effective doses resulting from various combinations of field of view size and field location comparing child and adult anthropomorphic phantoms with the recently introduced i-CAT FLX cone-beam computed tomography unit (Imaging Sciences, Hatfield, Pa) were measured with optical stimulated dosimetry using previously validated protocols. Scan protocols included high resolution (360° rotation, 600 image frames, 120 kV[p], 5 mA, 7.4 seconds), standard (360°, 300 frames, 120 kV[p], 5 mA, 3.7 seconds), QuickScan (180°, 160 frames, 120 kV[p], 5 mA, 2 seconds), and QuickScan+ (180°, 160 frames, 90 kV[p], 3 mA, 2 seconds). Contrast-to-noise ratio was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. Child phantom doses were on average 36% greater than adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than standard protocols for the child (P = 0.0167) and adult (P = 0.0055) phantoms. The 13 × 16-cm cephalometric fields of view ranged from 11 to 85 μSv in the adult phantom and 18 to 120 μSv in the child phantom for the QuickScan+ and standard protocols, respectively. The contrast-to-noise ratio was reduced by approximately two thirds when comparing QuickScan+ with standard exposure parameters. QuickScan+ effective doses are comparable with conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off might be acceptable for certain diagnostic tasks such as interim assessment of treatment results. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

The ACR-NEMA Digital Imaging And Communications Standard: Evolution, Overview And Implementation Considerations

NASA Astrophysics Data System (ADS)

Alzner, Edgar; Murphy, Laura

1986-06-01

The growing digital nature of radiology images led to a recognition that compatibility of communication between imaging, display and data storage devices of different modalities and different manufacturers is necessary. The ACR-NEMA Digital Imaging and Communications Standard Committee was formed to develop a communications standard for radiological images. This standard includes the overall structure of a communication message and the protocols for bi-directional communication using end-to-end connections. The evolution and rationale of the ACR-NEMA Digital Imaging and Communication Standard are described. An overview is provided and sane practical implementation considerations are discussed. PACS will became reality only if the medical community accepts and implements the ACR-NEMA Standard.

Advances in Imaging and Management Trends of Traumatic Aortic Injuries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagpal, Prashant, E-mail: drprashantnagpal@gmail.com, E-mail: Prashant-nagpal@uiowa.edu; Mullan, Brian F.; Sen, Indrani

Acute traumatic aortic injury (ATAI) is a life-threatening injury. CT is the imaging tool of choice, and the knowledge of direct and indirect signs of injury, grading system, and current management protocol helps the emergency radiologist to better identify and classify the injury and provide additional details that can impact management options. Newer dual-source CT technology with ultrafast acquisition speed has also influenced the appropriate protocol for imaging in patients with suspected ATAI. This review highlights the imaging protocol in patients with blunt trauma, CT appearance and grading systems of ATAI, management options, and the role of the multidisciplinary teammore » in the management of these patients. We also briefly review the current literature on the definition, treatment, and follow-up protocol in patients with minimal aortic injury.« less

Effects of exercise training on systo-diastolic ventricular dysfunction in patients with hypertension: an echocardiographic study with tissue velocity and strain imaging evaluation.

PubMed

Leggio, Massimo; Mazza, Andrea; Cruciani, Giancarlo; Sgorbini, Luca; Pugliese, Marco; Bendini, Maria Grazia; Severi, Paolo; Jesi, Anna Patrizia

2014-07-01

There is a lack of detailed data regarding the effect of exercise training in pharmacologically treated hypertensive patients. Therefore, the aim of this study was to evaluate the effects of exercise training on left and right ventricular morphologic and functional parameters by means of conventional echocardiography and sensitive new echocardiographic techniques including tissue Doppler velocity and strain imaging, that were performed in pharmacologically treated hypertensive patients at baseline and at the end of a specific exercise training protocol for primary prevention of cardiovascular disease. We selected 116 pharmacologically treated hypertensive patients who completed the exercise training protocol. All patients underwent a clinical history and examination; transthoracic echocardiography and exercise testing were performed at baseline and at the end of the exercise training protocol. Conventional echocardiography revealed a mild degree of diastolic dysfunction without significant differences or variations from baseline to the end of the exercise training protocol. In contrast, tissue Doppler velocity and strain imaging measurements demonstrated and highlighted the positive influence of exercise training: for both left and right ventricle myocardial early peak diastolic velocities (Em), the ratio of myocardial early-late peak diastolic velocity (Em/Am), myocardial peak systolic velocities (Sm) and peak strain and strain rate values significantly increased at the end of the exercise training protocol, suggesting a relationship between exercise capacity and both left and right ventricular systo-diastolic function. Our study, by means of newer more sensitive echocardiographic techniques, clearly demonstrated the positive impact of exercise training on both left and right ventricular systo-diastolic function, in terms of adjunctive subclinical improvement, in pharmacologically treated hypertensive patients.

Head CT: Image quality improvement with ASIR-V using a reduced radiation dose protocol for children.

PubMed

Kim, Hyun Gi; Lee, Ho-Joon; Lee, Seung-Koo; Kim, Hyun Ji; Kim, Myung-Joon

2017-09-01

To investigate the quality of images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V), using pediatric head CT protocols. A phantom was scanned at decreasing 20% mA intervals using our standard pediatric head CT protocols. Each study was then reconstructed at 10% ASIR-V intervals. After the phantom study, we reduced mA by 10% in the protocol for <3-year-old patients and applied 30% ASIR-V and by 30% in the protocol for 3- to 15-year-old patients and applied 40% ASIR-V. Increasing the percentage of ASIR-V resulted in lower noise and higher contrast-to-noise ratio (CNR) and preserved spatial resolution in the phantom study. Compared to a conventional-protocol, reduced-dose protocol with ASIR-V achieved 12.8% to 34.0% of dose reduction and showed images of lower noise (9.22 vs. 10.73, P = 0.043) and higher CNR in different levels (centrum semiovale, 2.14 vs. 1.52, P = 0.003; basal ganglia, 1.46 vs. 1.07, P = 0.001; and cerebellum, 2.18 vs. 1.33, P < 0.001). Qualitative analysis showed higher gray-white matter differentiation and sharpness and preserved overall diagnostic quality in the images with ASIR-V. Use of ASIR-V allowed a 12.8% to 34.0% dose reduction in each age group with potential to improve image quality. • It is possible to reduce radiation dose and improve image quality with ASIR-V. • We improved noise and CNR and decreased radiation dose. • Sharpness improved with ASIR-V. • Total radiation dose was decreased by 12.8% to 34.0%.

Interoperative fundus image and report sharing in compliance with integrating the healthcare enterprise conformance and web access to digital imaging and communication in medicine persistent object protocol.

PubMed

Wu, Hui-Qun; Lv, Zheng-Min; Geng, Xing-Yun; Jiang, Kui; Tang, Le-Min; Zhou, Guo-Min; Dong, Jian-Cheng

2013-01-01

To address issues in interoperability between different fundus image systems, we proposed a web eye-picture archiving and communication system (PACS) framework in conformance with digital imaging and communication in medicine (DICOM) and health level 7 (HL7) protocol to realize fundus images and reports sharing and communication through internet. Firstly, a telemedicine-based eye care work flow was established based on integrating the healthcare enterprise (IHE) Eye Care technical framework. Then, a browser/server architecture eye-PACS system was established in conformance with the web access to DICOM persistent object (WADO) protocol, which contains three tiers. In any client system installed with web browser, clinicians could log in the eye-PACS to observe fundus images and reports. Multipurpose internet mail extensions (MIME) type of a structured report is saved as pdf/html with reference link to relevant fundus image using the WADO syntax could provide enough information for clinicians. Some functions provided by open-source Oviyam could be used to query, zoom, move, measure, view DICOM fundus images. Such web eye-PACS in compliance to WADO protocol could be used to store and communicate fundus images and reports, therefore is of great significance for teleophthalmology.

Application of SEM and EDX in studying biomineralization in plant tissues.

PubMed

He, Honghua; Kirilak, Yaowanuj

2014-01-01

This chapter describes protocols using formalin-acetic acid-alcohol (FAA) to fix plant tissues for studying biomineralization by means of scanning electron microscopy (SEM) and qualitative energy-dispersive X-ray microanalysis (EDX). Specimen preparation protocols for SEM and EDX mainly include fixation, dehydration, critical point drying (CPD), mounting, and coating. Gold-coated specimens are used for SEM imaging, while gold- and carbon-coated specimens are prepared for qualitative X-ray microanalyses separately to obtain complementary information on the elemental compositions of biominerals. During the specimen preparation procedure for SEM, some biominerals may be dislodged or scattered, making it difficult to determine their accurate locations, and light microscopy is used to complement SEM studies. Specimen preparation protocols for light microscopy generally include fixation, dehydration, infiltration and embedding with resin, microtome sectioning, and staining. In addition, microwave processing methods are adopted here to speed up the specimen preparation process for both SEM and light microscopy.

Early-Dynamic Positron Emission Tomography (PET)/Computed Tomography and PET Angiography for Endoleak Detection After Endovascular Aneurysm Repair.

PubMed

Drescher, Robert; Gühne, Falk; Freesmeyer, Martin

2017-06-01

To propose a positron emission tomography (PET)/computed tomography (CT) protocol including early-dynamic and late-phase acquisitions to evaluate graft patency and aneurysm diameter, detect endoleaks, and rule out graft or vessel wall inflammation after endovascular aneurysm repair (EVAR) in one examination without intravenous contrast medium. Early-dynamic PET/CT of the endovascular prosthesis is performed for 180 seconds immediately after intravenous injection of F-18-fluorodeoxyglucose. Data are reconstructed in variable time frames (time periods after tracer injection) to visualize the arterial anatomy and are displayed as PET angiography or fused with CT images. Images are evaluated in view of vascular abnormalities, graft configuration, and tracer accumulation in the aneurysm sac. Whole-body PET/CT is performed 90 to 120 minutes after tracer injection. This protocol for early-dynamic PET/CT and PET angiography has the potential to evaluate vascular diseases, including the diagnosis of complications after endovascular procedures.

Live imaging of mitosis in the developing mouse embryonic cortex.

PubMed

Pilaz, Louis-Jan; Silver, Debra L

2014-06-04

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the developing cerebral cortex, abnormal mitosis of neural progenitors can cause defects in brain size and function. Hence, there is a critical need for tools to understand the mechanisms of neural progenitor mitosis. Cortical development in rodents is an outstanding model for studying this process. Neural progenitor mitosis is commonly examined in fixed brain sections. This protocol will describe in detail an approach for live imaging of mitosis in ex vivo embryonic brain slices. We will describe the critical steps for this procedure, which include: brain extraction, brain embedding, vibratome sectioning of brain slices, staining and culturing of slices, and time-lapse imaging. We will then demonstrate and describe in detail how to perform post-acquisition analysis of mitosis. We include representative results from this assay using the vital dye Syto11, transgenic mice (histone H2B-EGFP and centrin-EGFP), and in utero electroporation (mCherry-α-tubulin). We will discuss how this procedure can be best optimized and how it can be modified for study of genetic regulation of mitosis. Live imaging of mitosis in brain slices is a flexible approach to assess the impact of age, anatomy, and genetic perturbation in a controlled environment, and to generate a large amount of data with high temporal and spatial resolution. Hence this protocol will complement existing tools for analysis of neural progenitor mitosis.

SU-E-CAMPUS-J-04: Image Guided Radiation Therapy (IGRT): Review of Technical Standards and Credentialing in Radiotherapy Clinical Trials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giaddui, T; Chen, W; Yu, J

2014-06-15

Purpose: To review IGRT credentialing experience and unexpected technical issues encountered in connection with advanced radiotherapy technologies as implemented in RTOG clinical trials. To update IGRT credentialing procedures with the aim of improving the quality of the process, and to increase the proportion of IGRT credentialing compliance. To develop a living disease site-specific IGRT encyclopedia. Methods: Numerous technical issues were encountered during the IGRT credentialing process. The criteria used for credentialing review were based on: image quality; anatomy included in fused data sets and shift results. Credentialing requirements have been updated according to the AAPM task group reports for IGRTmore » to ensure that all required technical items are included in the quality review process. Implementation instructions have been updated and expanded for recent protocols. Results: Technical issues observed during the credentialing review process include, but are not limited to: poor quality images; inadequate image acquisition region; poor data quality; shifts larger than acceptable; no soft tissue surrogate. The updated IGRT credentialing process will address these issues and will also include the technical items required from AAPM: TG 104; TG 142 and TG 179 reports. An instruction manual has been developed describing a remote credentialing method for reviewers. Submission requirements are updated, including images/documents as well as facility questionnaire. The review report now includes summary of the review process and the parameters that reviewers check. We have reached consensus on the minimum IGRT technical requirement for a number of disease sites. RTOG 1311(NRG-BR002A Phase 1 Study of Stereotactic Body Radiotherapy (SBRT) for the Treatment of Multiple Metastases) is an example, here; the protocol specified the minimum requirement for each anatomical sites (with/without fiducials). Conclusion: Technical issues are identified and reported. IGRT guidelines are updated, with the corresponding credentialing requirements. An IGRT encyclopedia describing site-specific implementation issues is currently in development.« less

Automated processing of first-pass radioisotope ventriculography data to determine essential central circulation parameters

NASA Astrophysics Data System (ADS)

Krotov, Aleksei; Pankin, Victor

2017-09-01

The assessment of central circulation (including heart function) parameters is vital in the preventive diagnostics of inherent and acquired heart failures and during polychemotherapy. The protocols currently applied in Russia do not fully utilize the first-pass assessment (FPRNA) and that results in poor data formalization, while the FPRNA is the one of the fastest, affordable and compact methods among other radioisotope diagnostics protocols. A non-imaging algorithm basing on existing protocols has been designed to use the readings of an additional detector above vena subclavia to determine the total blood volume (TBV), not requiring blood sampling in contrast to current protocols. An automated processing of precordial detector readings is presented, in order to determine the heart strike volume (SV). Two techniques to estimate the ejection fraction (EF) of the heart are discussed.

Imaging of Lipids and Metabolites Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanekoff, Ingela; Laskin, Julia

In recent years, mass spectroscopy imaging (MSI) has emerged as a foundational technique in metabolomics and drug screening providing deeper understanding of complex mechanistic pathways within biochemical systems and biological organisms. We have been invited to contribute a chapter to a new Springer series volume, entitled “Mass Spectrometry Imaging of Small Molecules”. The volume is planned for the highly successful lab protocol series Methods in Molecular Biology, published by Humana Press, USA. The volume is aimed to equip readers with step-by-step mass spectrometric imaging protocols and bring rapidly maturing methods of MS imaging to life science researchers. The chapter willmore » provide a detailed protocol of ambient MSI by use of nanospray desorption electrospray ionization.« less

A cross-platform survey of CT image quality and dose from routine abdomen protocols and a method to systematically standardize image quality.

PubMed

Favazza, Christopher P; Duan, Xinhui; Zhang, Yi; Yu, Lifeng; Leng, Shuai; Kofler, James M; Bruesewitz, Michael R; McCollough, Cynthia H

2015-11-07

Through this investigation we developed a methodology to evaluate and standardize CT image quality from routine abdomen protocols across different manufacturers and models. The influence of manufacturer-specific automated exposure control systems on image quality was directly assessed to standardize performance across a range of patient sizes. We evaluated 16 CT scanners across our health system, including Siemens, GE, and Toshiba models. Using each practice's routine abdomen protocol, we measured spatial resolution, image noise, and scanner radiation output (CTDIvol). Axial and in-plane spatial resolutions were assessed through slice sensitivity profile (SSP) and modulation transfer function (MTF) measurements, respectively. Image noise and CTDIvol values were obtained for three different phantom sizes. SSP measurements demonstrated a bimodal distribution in slice widths: an average of 6.2  ±  0.2 mm using GE's 'Plus' mode reconstruction setting and 5.0  ±  0.1 mm for all other scanners. MTF curves were similar for all scanners. Average spatial frequencies at 50%, 10%, and 2% MTF values were 3.24  ±  0.37, 6.20  ±  0.34, and 7.84  ±  0.70 lp cm(-1), respectively. For all phantom sizes, image noise and CTDIvol varied considerably: 6.5-13.3 HU (noise) and 4.8-13.3 mGy (CTDIvol) for the smallest phantom; 9.1-18.4 HU and 9.3-28.8 mGy for the medium phantom; and 7.8-23.4 HU and 16.0-48.1 mGy for the largest phantom. Using these measurements and benchmark SSP, MTF, and image noise targets, CT image quality can be standardized across a range of patient sizes.

Validation of a Monte Carlo simulation of the Philips Allegro/GEMINI PET systems using GATE

NASA Astrophysics Data System (ADS)

Lamare, F.; Turzo, A.; Bizais, Y.; Cheze LeRest, C.; Visvikis, D.

2006-02-01

A newly developed simulation toolkit, GATE (Geant4 Application for Tomographic Emission), was used to develop a Monte Carlo simulation of a fully three-dimensional (3D) clinical PET scanner. The Philips Allegro/GEMINI PET systems were simulated in order to (a) allow a detailed study of the parameters affecting the system's performance under various imaging conditions, (b) study the optimization and quantitative accuracy of emission acquisition protocols for dynamic and static imaging, and (c) further validate the potential of GATE for the simulation of clinical PET systems. A model of the detection system and its geometry was developed. The accuracy of the developed detection model was tested through the comparison of simulated and measured results obtained with the Allegro/GEMINI systems for a number of NEMA NU2-2001 performance protocols including spatial resolution, sensitivity and scatter fraction. In addition, an approximate model of the system's dead time at the level of detected single events and coincidences was developed in an attempt to simulate the count rate related performance characteristics of the scanner. The developed dead-time model was assessed under different imaging conditions using the count rate loss and noise equivalent count rates performance protocols of standard and modified NEMA NU2-2001 (whole body imaging conditions) and NEMA NU2-1994 (brain imaging conditions) comparing simulated with experimental measurements obtained with the Allegro/GEMINI PET systems. Finally, a reconstructed image quality protocol was used to assess the overall performance of the developed model. An agreement of <3% was obtained in scatter fraction, with a difference between 4% and 10% in the true and random coincidence count rates respectively, throughout a range of activity concentrations and under various imaging conditions, resulting in <8% differences between simulated and measured noise equivalent count rates performance. Finally, the image quality validation study revealed a good agreement in signal-to-noise ratio and contrast recovery coefficients for a number of different volume spheres and two different (clinical level based) tumour-to-background ratios. In conclusion, these results support the accurate modelling of the Philips Allegro/GEMINI PET systems using GATE in combination with a dead-time model for the signal flow description, which leads to an agreement of <10% in coincidence count rates under different imaging conditions and clinically relevant activity concentration levels.

Evaluating a preoperative protocol that includes magnetic resonance imaging for lymph node metastasis in the Cholangiocarcinoma Screening and Care Program (CASCAP) in Thailand.

PubMed

Songthamwat, Metha; Chamadol, Nittaya; Khuntikeo, Narong; Thinkhamrop, Jadsada; Koonmee, Supinda; Chaichaya, Nathaphop; Bethony, Jeffrey; Thinkhamrop, Bandit

2017-09-20

Treatment planning especially liver resection in cholangiocarcinoma (CCA) depends on the extension of tumor and lymph node metastasis which is included as a key criterion for operability. Magnetic resonance imaging (MRI) offers a rapid and powerful tool for the detection of lymph node metastasis (LNM) and in the current manuscript is assessed as a critical tool in the preoperative protocol for liver resection for treatment of CCA. However, the accuracy of MRI to detect LNM from CCA had yet to be comprehensively evaluated. The accuracy of MRI to detect LNM was assessed in a cohort of individuals with CCA from the Cholangiocarcinoma Screening and Care Program (CASCAP), a screening program designed to reduce CCA in Northeastern Thailand by community-based ultrasound (US) for CCA. CCA-positive individuals are referred to one of the nine tertiary centers in the study to undergo a preoperative protocol that included enhanced imaging by MRI. Additionally, these individuals also underwent lymph node biopsies for histological confirmation of LNM (the "gold standard") to determine the accuracy of the MRI results. MRI accurately detected the presence or absence of LNM in only 29 out of the 51 CCA cases (56.9%, 95% CI 42.2-70.7), resulting in a sensitivity of 57.1% (95% CI 34.0-78.2) and specificity of 56.7% (95% CI 37.4-74.5), with positive and negative predictive values of 48.0% (95% CI 27.8-68.7) and 65.4% (95% CI 44.3-82.8), respectively. The positive likelihood ratio was 1.32 (95% CI 0.76-2.29), and the negative likelihood ratio was 0.76 (95% CI 0.42-1.36). MRI showed limited sensitivity and a poor positive predictive value for the diagnosis of LNM for CCA, which is of particular concern in this resource-limited setting, where simpler detection methods could be utilized that are more cost-effective in this region of Thailand. Therefore, the inclusion of MRI, a costly imaging method, should be reconsidered as part of protocol for treatment planning of CCA, given the number of false positives, especially as it is critical in determining the operability for CCA subjects.

Embedding and Chemical Reactivation of Green Fluorescent Protein in the Whole Mouse Brain for Optical Micro-Imaging

PubMed Central

Gang, Yadong; Zhou, Hongfu; Jia, Yao; Liu, Ling; Liu, Xiuli; Rao, Gong; Li, Longhui; Wang, Xiaojun; Lv, Xiaohua; Xiong, Hanqing; Yang, Zhongqin; Luo, Qingming; Gong, Hui; Zeng, Shaoqun

2017-01-01

Resin embedding has been widely applied to fixing biological tissues for sectioning and imaging, but has long been regarded as incompatible with green fluorescent protein (GFP) labeled sample because it reduces fluorescence. Recently, it has been reported that resin-embedded GFP-labeled brain tissue can be imaged with high resolution. In this protocol, we describe an optimized protocol for resin embedding and chemical reactivation of fluorescent protein labeled mouse brain, we have used mice as experiment model, but the protocol should be applied to other species. This method involves whole brain embedding and chemical reactivation of the fluorescent signal in resin-embedded tissue. The whole brain embedding process takes a total of 7 days. The duration of chemical reactivation is ~2 min for penetrating 4 μm below the surface in the resin-embedded brain. This protocol provides an efficient way to prepare fluorescent protein labeled sample for high-resolution optical imaging. This kind of sample was demonstrated to be imaged by various optical micro-imaging methods. Fine structures labeled with GFP across a whole brain can be detected. PMID:28352214

GUI implementation of image encryption and decryption using Open CV-Python script on secured TFTP protocol

NASA Astrophysics Data System (ADS)

Reddy, K. Rasool; Rao, Ch. Madhava

2018-04-01

Currently safety is one of the primary concerns in the transmission of images due to increasing the use of images within the industrial applications. So it's necessary to secure the image facts from unauthorized individuals. There are various strategies are investigated to secure the facts. In that encryption is certainly one of maximum distinguished method. This paper gives a sophisticated Rijndael (AES) algorithm to shield the facts from unauthorized humans. Here Exponential Key Change (EKE) concept is also introduced to exchange the key between client and server. The things are exchange in a network among client and server through a simple protocol is known as Trivial File Transfer Protocol (TFTP). This protocol is used mainly in embedded servers to transfer the data and also provide protection to the data if protection capabilities are integrated. In this paper, implementing a GUI environment for image encryption and decryption. All these experiments carried out on Linux environment the usage of Open CV-Python script.

Improved diagnosis of common bile duct stone with single-shot balanced turbo field-echo sequence in MRCP.

PubMed

Noda, Yoshifumi; Goshima, Satoshi; Kojima, Toshihisa; Kawaguchi, Shimpei; Kawada, Hiroshi; Kawai, Nobuyuki; Koyasu, Hiromi; Matsuo, Masayuki; Bae, Kyongtae T

2017-04-01

To evaluate the value of adding single-shot balanced turbo field-echo (b-TFE) sequence to conventional magnetic resonance cholangiopancreatography (MRCP) for the detection of common bile duct (CBD) stone. One hundred thirty-seven consecutive patients with suspected CBD stone underwent MRCP including single-shot b-TFE sequence. Twenty-five patients were confirmed with CBD stone by endoscopic retrograde cholangiopancreatography or ultrasonography. Two radiologists reviewed two image protocols: protocol A (conventional MRCP protocol: unenhanced T1-, T2-, and respiratory-triggered three-dimensional fat-suppressed single-shot turbo spin-echo MRCP sequence) and protocol B (protocol A plus single-shot b-TFE sequence). The sensitivity, specificity, positive (PPV) and negative predictive value (NPV), and area under the receiver-operating-characteristic (ROC) curve (AUC) for the detection of CBD stone were compared. The sensitivity (72%) and NPV (94%) were the same between the two protocols. However, protocol B was greater in the specificity (99%) and PPV (94%) than protocol A (92% and 67%, respectively) (P = 0.0078 and 0.031, respectively). The AUC was significantly greater for protocol B (0.93) than for protocol A (0.86) (P = 0.026). Inclusion of single-shot b-TFE sequence to conventional MRCP significantly improved the specificity and PPV for the detection of CBD stone.

Live-cell imaging of mammalian RNAs with Spinach2.

PubMed

Strack, Rita L; Jaffrey, Samie R

2015-01-01

The ability to monitor RNAs of interest in living cells is crucial to understanding the function, dynamics, and regulation of this important class of molecules. In recent years, numerous strategies have been developed with the goal of imaging individual RNAs of interest in living cells, each with their own advantages and limitations. This chapter provides an overview of current methods of live-cell RNA imaging, including a detailed discussion of genetically encoded strategies for labeling RNAs in mammalian cells. This chapter then focuses on the development and use of "RNA mimics of GFP" or Spinach technology for tagging mammalian RNAs and includes a detailed protocol for imaging 5S and CGG60 RNA with the recently described Spinach2 tag. © 2015 Elsevier Inc. All rights reserved.

The Role of Magnetic Resonance Imaging in Athletic Pubalgia and Core Muscle Injury.

PubMed

Coker, Dana J; Zoga, Adam C

2015-08-01

Magnetic resonance imaging (MRI) has become the standard of care imaging modality for a difficult, often misunderstood spectrum of musculoskeletal injury termed athletic pubalgia or core muscle injury. Armed with a dedicated noncontrast athletic pubalgia protocol and a late model phased array receiver coil, the musculoskeletal imager can play a great role in effective diagnosis and treatment planning for lesions, including osteitis pubis, midline pubic plate lesions, and rectus abdominis/adductor aponeurosis injury. Beyond these established patterns of MRI findings, there are many confounders and contributing pathologies about the pelvis in patients with activity related groin pain, including internal and periarticular derangements of the hip. The MRI is ideally suited to delineate the extent of expected injury and to identify the unexpected visceral and musculoskeletal lesions.

Comparison of breathing gated CT images generated using a 5DCT technique and a commercial clinical protocol in a porcine model

PubMed Central

O’Connell, Dylan P.; Thomas, David H.; Dou, Tai H.; Lamb, James M.; Feingold, Franklin; Low, Daniel A.; Fuld, Matthew K.; Sieren, Jered P.; Sloan, Chelsea M.; Shirk, Melissa A.; Hoffman, Eric A.; Hofmann, Christian

2015-01-01

Purpose: To demonstrate that a “5DCT” technique which utilizes fast helical acquisition yields the same respiratory-gated images as a commercial technique for regular, mechanically produced breathing cycles. Methods: Respiratory-gated images of an anesthetized, mechanically ventilated pig were generated using a Siemens low-pitch helical protocol and 5DCT for a range of breathing rates and amplitudes and with standard and low dose imaging protocols. 5DCT reconstructions were independently evaluated by measuring the distances between tissue positions predicted by a 5D motion model and those measured using deformable registration, as well by reconstructing the originally acquired scans. Discrepancies between the 5DCT and commercial reconstructions were measured using landmark correspondences. Results: The mean distance between model predicted tissue positions and deformably registered tissue positions over the nine datasets was 0.65 ± 0.28 mm. Reconstructions of the original scans were on average accurate to 0.78 ± 0.57 mm. Mean landmark displacement between the commercial and 5DCT images was 1.76 ± 1.25 mm while the maximum lung tissue motion over the breathing cycle had a mean value of 27.2 ± 4.6 mm. An image composed of the average of 30 deformably registered images acquired with a low dose protocol had 6 HU image noise (single standard deviation) in the heart versus 31 HU for the commercial images. Conclusions: An end to end evaluation of the 5DCT technique was conducted through landmark based comparison to breathing gated images acquired with a commercial protocol under highly regular ventilation. The techniques were found to agree to within 2 mm for most respiratory phases and most points in the lung. PMID:26133604

How to Fabricate Functional Artificial Luciferases for Bioassays.

PubMed

Kim, Sung-Bae; Fujii, Rika

2016-01-01

The present protocol introduces fabrication of artificial luciferases (ALuc(®)) by extracting the consensus amino acids from the alignment of copepod luciferase sequences. The made ALucs have unique sequential identities that are phylogenetically distinctive from those of any existing copepod luciferase. Some ALucs exhibited heat stability, and strong and greatly prolonged optical intensities. The made ALucs are applicable to various bioassays as an optical readout, including live cell imaging, single-chain probes, and bioluminescent tags of antibodies. The present protocol guides on how to fabricate a unique artificial luciferase with designed optical properties and functionalities.

SU-E-I-33: Initial Evaluation of Model-Based Iterative CT Reconstruction Using Standard Image Quality Phantoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gingold, E; Dave, J

2014-06-01

Purpose: The purpose of this study was to compare a new model-based iterative reconstruction with existing reconstruction methods (filtered backprojection and basic iterative reconstruction) using quantitative analysis of standard image quality phantom images. Methods: An ACR accreditation phantom (Gammex 464) and a CATPHAN600 phantom were scanned using 3 routine clinical acquisition protocols (adult axial brain, adult abdomen, and pediatric abdomen) on a Philips iCT system. Each scan was acquired using default conditions and 75%, 50% and 25% dose levels. Images were reconstructed using standard filtered backprojection (FBP), conventional iterative reconstruction (iDose4) and a prototype model-based iterative reconstruction (IMR). Phantom measurementsmore » included CT number accuracy, contrast to noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD), and noise power spectrum (NPS). Results: The choice of reconstruction method had no effect on CT number accuracy, or MTF (p<0.01). The CNR of a 6 HU contrast target was improved by 1–67% with iDose4 relative to FBP, while IMR improved CNR by 145–367% across all protocols and dose levels. Within each scan protocol, the CNR improvement from IMR vs FBP showed a general trend of greater improvement at lower dose levels. NPS magnitude was greatest for FBP and lowest for IMR. The NPS of the IMR reconstruction showed a pronounced decrease with increasing spatial frequency, consistent with the unusual noise texture seen in IMR images. Conclusion: Iterative Model Reconstruction reduces noise and improves contrast-to-noise ratio without sacrificing spatial resolution in CT phantom images. This offers the possibility of radiation dose reduction and improved low contrast detectability compared with filtered backprojection or conventional iterative reconstruction.« less

OC ToGo: bed site image integration into OpenClinica with mobile devices

NASA Astrophysics Data System (ADS)

Haak, Daniel; Gehlen, Johan; Jonas, Stephan; Deserno, Thomas M.

2014-03-01

Imaging and image-based measurements nowadays play an essential role in controlled clinical trials, but electronic data capture (EDC) systems insufficiently support integration of captured images by mobile devices (e.g. smartphones and tablets). The web application OpenClinica has established as one of the world's leading EDC systems and is used to collect, manage and store data of clinical trials in electronic case report forms (eCRFs). In this paper, we present a mobile application for instantaneous integration of images into OpenClinica directly during examination on patient's bed site. The communication between the Android application and OpenClinica is based on the simple object access protocol (SOAP) and representational state transfer (REST) web services for metadata, and secure file transfer protocol (SFTP) for image transfer, respectively. OpenClinica's web services are used to query context information (e.g. existing studies, events and subjects) and to import data into the eCRF, as well as export of eCRF metadata and structural information. A stable image transfer is ensured and progress information (e.g. remaining time) visualized to the user. The workflow is demonstrated for a European multi-center registry, where patients with calciphylaxis disease are included. Our approach improves the EDC workflow, saves time, and reduces costs. Furthermore, data privacy is enhanced, since storage of private health data on the imaging devices becomes obsolete.

Technical innovation changes standard radiographic protocols in veterinary medicine: is it necessary to obtain two dorsoproximal-palmarodistal oblique views of the equine foot when using computerised radiography systems?

PubMed

Whitlock, J; Dixon, J; Sherlock, C; Tucker, R; Bolt, D M; Weller, R

2016-05-21

Since the 1950s, veterinary practitioners have included two separate dorsoproximal-palmarodistal oblique (DPr-PaDiO) radiographs as part of a standard series of the equine foot. One image is obtained to visualise the distal phalanx and the other to visualise the navicular bone. However, rapid development of computed radiography and digital radiography and their post-processing capabilities could mean that this practice is no longer required. The aim of this study was to determine differences in perceived image quality between DPr-PaDiO radiographs that were acquired with a computerised radiography system with exposures, centring and collimation recommended for the navicular bone versus images acquired for the distal phalanx but were subsequently manipulated post-acquisition to highlight the navicular bone. Thirty images were presented to four clinicians for quality assessment and graded using a 1-3 scale (1=textbook quality, 2=diagnostic quality, 3=non-diagnostic image). No significant difference in diagnostic quality was found between the original navicular bone images and the manipulated distal phalanx images. This finding suggests that a single DPr-PaDiO image of the distal phalanx is sufficient for an equine foot radiographic series, with appropriate post-processing and manipulation. This change in protocol will result in reduced radiographic study time and decreased patient/personnel radiation exposure. British Veterinary Association.

"First generation" automated DNA sequencing technology.

PubMed

Slatko, Barton E; Kieleczawa, Jan; Ju, Jingyue; Gardner, Andrew F; Hendrickson, Cynthia L; Ausubel, Frederick M

2011-10-01

Beginning in the 1980s, automation of DNA sequencing has greatly increased throughput, reduced costs, and enabled large projects to be completed more easily. The development of automation technology paralleled the development of other aspects of DNA sequencing: better enzymes and chemistry, separation and imaging technology, sequencing protocols, robotics, and computational advancements (including base-calling algorithms with quality scores, database developments, and sequence analysis programs). Despite the emergence of high-throughput sequencing platforms, automated Sanger sequencing technology remains useful for many applications. This unit provides background and a description of the "First-Generation" automated DNA sequencing technology. It also includes protocols for using the current Applied Biosystems (ABI) automated DNA sequencing machines. © 2011 by John Wiley & Sons, Inc.

Radionuclide bone scan SPECT-CT: lowering the dose of CT significantly reduces radiation dose without impacting CT image quality

PubMed Central

Gupta, Sandeep Kumar; Trethewey, Scott; Brooker, Bree; Rutherford, Natalie; Diffey, Jenny; Viswanathan, Suresh; Attia, John

2017-01-01

The CT component of SPECT-CT is required for attenuation correction and anatomical localization of the uptake on SPECT but there is no guideline about the optimal CT acquisition parameters. In our department, a standard CT acquisition protocol was changed in 2013 to give lower radiation dose to the patient. In this study, we retrospectively compared the effects on patient dose as well as the CT image quality with current versus older CT protocols. Ninety nine consecutive patients [n=51 Standard dose ‘old’ protocol (SDP); n=48 lower dose ‘new’ protocol (LDP)] with lumbar spine SPECT-CT for bone scan were examined. The main differences between the two protocols were that SDP used 130 kVp tube voltage and reference current-time product of 70 mAs whereas the LDP used 110 kVp and 40 mAs respectively. Various quantitative parameters from the CT images were obtained and the images were also rated blindly by two experienced nuclear medicine physicians for bony definition and noise. The mean calculated dose length product of the LDP group (121.5±39.6 mGy.cm) was significantly lower compared to the SDP group patients (266.9±96.9 mGy.cm; P<0.0001). This translated into a significant reduction in the mean effective dose to 1.8 mSv from 4.0 mSv. The physicians reported better CT image quality for the bony structures in LDP group although for soft tissue structures, the SDP group had better image quality. The optimized new CT acquisition protocol significantly reduced the radiation dose to the patient and in-fact improved CT image quality for the assessment of bony structures. PMID:28533938

Submaximal delayed-onset muscle soreness: correlations between MR imaging findings and clinical measures

NASA Technical Reports Server (NTRS)

Evans, G. F.; Haller, R. G.; Wyrick, P. S.; Parkey, R. W.; Fleckenstein, J. L.; Blomqvist, C. G. (Principal Investigator)

1998-01-01

PURPOSE: To assess correlations between muscle edema on magnetic resonance (MR) images and clinical indexes of muscle injury in delayed-onset muscle soreness (DOMS) produced by submaximal exercise protocols. MATERIALS AND METHODS: Sixteen subjects performed 36 elbow flexions ("biceps curls") at one of two submaximal workloads that emphasized eccentric contractions. Changes in MR imaging findings, plasma levels of creatine kinase, and pain scores were correlated. RESULTS: Both exercise protocols produced DOMS in all subjects. The best correlation was between change in creatine kinase level and volume of muscle edema on MR images, regardless of the workload. Correlations tended to be better with the easier exercise protocol. CONCLUSION: Whereas many previous studies of DOMS focused on intense exercise protocols to ensure positive results, the present investigation showed that submaximal workloads are adequate to produce DOMS and that correlations between conventionally measured indexes of injury may be enhanced at lighter exercise intensities.

Quality control for quantitative multicenter whole-body PET/MR studies: A NEMA image quality phantom study with three current PET/MR systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boellaard, Ronald, E-mail: r.boellaard@vumc.nl; European Association of Nuclear Medicine Research Ltd., Vienna 1060; European Association of Nuclear Medicine Physics Committee, Vienna 1060

2015-10-15

Purpose: Integrated positron emission tomography/magnetic resonance (PET/MR) systems derive the PET attenuation correction (AC) from dedicated MR sequences. While MR-AC performs reasonably well in clinical patient imaging, it may fail for phantom-based quality control (QC). The authors assess the applicability of different protocols for PET QC in multicenter PET/MR imaging. Methods: The National Electrical Manufacturers Association NU 2 2007 image quality phantom was imaged on three combined PET/MR systems: a Philips Ingenuity TF PET/MR, a Siemens Biograph mMR, and a GE SIGNA PET/MR (prototype) system. The phantom was filled according to the EANM FDG-PET/CT guideline 1.0 and scanned for 5more » min over 1 bed. Two MR-AC imaging protocols were tested: standard clinical procedures and a dedicated protocol for phantom tests. Depending on the system, the dedicated phantom protocol employs a two-class (water and air) segmentation of the MR data or a CT-based template. Differences in attenuation- and SUV recovery coefficients (RC) are reported. PET/CT-based simulations were performed to simulate the various artifacts seen in the AC maps (μ-map) and their impact on the accuracy of phantom-based QC. Results: Clinical MR-AC protocols caused substantial errors and artifacts in the AC maps, resulting in underestimations of the reconstructed PET activity of up to 27%, depending on the PET/MR system. Using dedicated phantom MR-AC protocols, PET bias was reduced to −8%. Mean and max SUV RC met EARL multicenter PET performance specifications for most contrast objects, but only when using the dedicated phantom protocol. Simulations confirmed the bias in experimental data to be caused by incorrect AC maps resulting from the use of clinical MR-AC protocols. Conclusions: Phantom-based quality control of PET/MR systems in a multicenter, multivendor setting may be performed with sufficient accuracy, but only when dedicated phantom acquisition and processing protocols are used for attenuation correction.« less

Comparison of different tissue clearing methods and 3D imaging techniques for visualization of GFP-expressing mouse embryos and embryonic hearts.

PubMed

Kolesová, Hana; Čapek, Martin; Radochová, Barbora; Janáček, Jiří; Sedmera, David

2016-08-01

Our goal was to find an optimal tissue clearing protocol for whole-mount imaging of embryonic and adult hearts and whole embryos of transgenic mice that would preserve green fluorescent protein GFP fluorescence and permit comparison of different currently available 3D imaging modalities. We tested various published organic solvent- or water-based clearing protocols intended to preserve GFP fluorescence in central nervous system: tetrahydrofuran dehydration and dibenzylether protocol (DBE), SCALE, CLARITY, and CUBIC and evaluated their ability to render hearts and whole embryos transparent. DBE clearing protocol did not preserve GFP fluorescence; in addition, DBE caused considerable tissue-shrinking artifacts compared to the gold standard BABB protocol. The CLARITY method considerably improved tissue transparency at later stages, but also decreased GFP fluorescence intensity. The SCALE clearing resulted in sufficient tissue transparency up to ED12.5; at later stages the useful depth of imaging was limited by tissue light scattering. The best method for the cardiac specimens proved to be the CUBIC protocol, which preserved GFP fluorescence well, and cleared the specimens sufficiently even at the adult stages. In addition, CUBIC decolorized the blood and myocardium by removing tissue iron. Good 3D renderings of whole fetal hearts and embryos were obtained with optical projection tomography and selective plane illumination microscopy, although at resolutions lower than with a confocal microscope. Comparison of five tissue clearing protocols and three imaging methods for study of GFP mouse embryos and hearts shows that the optimal method depends on stage and level of detail required.

Development of a calibration protocol for quantitative imaging for molecular radiotherapy dosimetry

NASA Astrophysics Data System (ADS)

Wevrett, J.; Fenwick, A.; Scuffham, J.; Nisbet, A.

2017-11-01

Within the field of molecular radiotherapy, there is a significant need for standardisation in dosimetry, in both quantitative imaging and dosimetry calculations. Currently, there are a wide range of techniques used by different clinical centres and as a result there is no means to compare patient doses between centres. To help address this need, a 3 year project was funded by the European Metrology Research Programme, and a number of clinical centres were involved in the project. One of the required outcomes of the project was to develop a calibration protocol for three dimensional quantitative imaging of volumes of interest. Two radionuclides were selected as being of particular interest: iodine-131 (131I, used to treat thyroid disorders) and lutetium-177 (177Lu, used to treat neuroendocrine tumours). A small volume of activity within a scatter medium (water), representing a lesion within a patient body, was chosen as the calibration method. To ensure ease of use in clinical centres, an "off-the-shelf" solution was proposed - to avoid the need for in-house manufacturing. The BIODEX elliptical Jaszczak phantom and 16 ml fillable sphere were selected. The protocol was developed for use on SPECT/CT gamma cameras only, where the CT dataset would be used to correct the imaging data for attenuation of the emitted photons within the phantom. The protocol corrects for scatter of emitted photons using the triple energy window correction technique utilised by most clinical systems. A number of clinical systems were tested in the development of this protocol, covering the major manufacturers of gamma camera generally used in Europe. Initial imaging was performed with 131I and 177Lu at a number of clinical centres, but due to time constraints in the project, some acquisitions were performed with 177Lu only. The protocol is relatively simplistic, and does not account for the effects of dead-time in high activity patients, the presence of background activity surrounding volumes of interest or the partial volume effect of imaging lesions smaller than 16 ml. The development of this simple protocol demonstrates that it is possible to produce a standardised quantitative imaging protocol for molecular radiotherapy dosimetry. However, the protocol needs further development to expand it to incorporate other radionuclides, and to account for the effects that have been disregarded in this initial version.

Contrast-Enhanced Magnetic Resonance Cholangiography: Practical Tips and Clinical Indications for Biliary Disease Management.

PubMed

Palmucci, Stefano; Roccasalva, Federica; Piccoli, Marina; Fuccio Sanzà, Giovanni; Foti, Pietro Valerio; Ragozzino, Alfonso; Milone, Pietro; Ettorre, Giovanni Carlo

2017-01-01

Since its introduction, MRCP has been improved over the years due to the introduction of several technical advances and innovations. It consists of a noninvasive method for biliary tree representation, based on heavily T2-weighted images. Conventionally, its protocol includes two-dimensional single-shot fast spin-echo images, acquired with thin sections or with multiple thick slabs. In recent years, three-dimensional T2-weighted fast-recovery fast spin-echo images have been added to the conventional protocol, increasing the possibility of biliary anatomy demonstration and leading to a significant benefit over conventional 2D imaging. A significant innovation has been reached with the introduction of hepatobiliary contrasts, represented by gadoxetic acid and gadobenate dimeglumine: they are excreted into the bile canaliculi, allowing the opacification of the biliary tree. Recently, 3D interpolated T1-weighted spoiled gradient echo images have been proposed for the evaluation of the biliary tree, obtaining images after hepatobiliary contrast agent administration. Thus, the acquisition of these excretory phases improves the diagnostic capability of conventional MRCP-based on T2 acquisitions. In this paper, technical features of contrast-enhanced magnetic resonance cholangiography are briefly discussed; main diagnostic tips of hepatobiliary phase are showed, emphasizing the benefit of enhanced cholangiography in comparison with conventional MRCP.

Synthesis of Immunotargeted Magneto-plasmonic Nanoclusters

PubMed Central

Wu, Chun-Hsien; Sokolov, Konstantin

2014-01-01

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications including contrast enhancement in novel magnetomotive imaging modalities, simultaneous capture and detection of circulating tumor cells (CTCs), and multimodal molecular imaging combined with photothermal therapy of cancer cells. These applications have stimulated significant interest in development of protocols for synthesis of magneto-plasmonic nanoparticles with optical absorbance in the near-infrared (NIR) region and a strong magnetic moment. Here, we present a novel protocol for synthesis of such hybrid nanoparticles that is based on an oil-in-water microemulsion method. The unique feature of the protocol described herein is synthesis of magneto-plasmonic nanoparticles of various sizes from primary blocks which also have magneto-plasmonic characteristics. This approach yields nanoparticles with a high density of magnetic and plasmonic functionalities which are uniformly distributed throughout the nanoparticle volume. The hybrid nanoparticles can be easily functionalized by attaching antibodies through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting. PMID:25177973

Model-based Iterative Reconstruction: Effect on Patient Radiation Dose and Image Quality in Pediatric Body CT

PubMed Central

Dillman, Jonathan R.; Goodsitt, Mitchell M.; Christodoulou, Emmanuel G.; Keshavarzi, Nahid; Strouse, Peter J.

2014-01-01

Purpose To retrospectively compare image quality and radiation dose between a reduced-dose computed tomographic (CT) protocol that uses model-based iterative reconstruction (MBIR) and a standard-dose CT protocol that uses 30% adaptive statistical iterative reconstruction (ASIR) with filtered back projection. Materials and Methods Institutional review board approval was obtained. Clinical CT images of the chest, abdomen, and pelvis obtained with a reduced-dose protocol were identified. Images were reconstructed with two algorithms: MBIR and 100% ASIR. All subjects had undergone standard-dose CT within the prior year, and the images were reconstructed with 30% ASIR. Reduced- and standard-dose images were evaluated objectively and subjectively. Reduced-dose images were evaluated for lesion detectability. Spatial resolution was assessed in a phantom. Radiation dose was estimated by using volumetric CT dose index (CTDIvol) and calculated size-specific dose estimates (SSDE). A combination of descriptive statistics, analysis of variance, and t tests was used for statistical analysis. Results In the 25 patients who underwent the reduced-dose protocol, mean decrease in CTDIvol was 46% (range, 19%–65%) and mean decrease in SSDE was 44% (range, 19%–64%). Reduced-dose MBIR images had less noise (P > .004). Spatial resolution was superior for reduced-dose MBIR images. Reduced-dose MBIR images were equivalent to standard-dose images for lungs and soft tissues (P > .05) but were inferior for bones (P = .004). Reduced-dose 100% ASIR images were inferior for soft tissues (P < .002), lungs (P < .001), and bones (P < .001). By using the same reduced-dose acquisition, lesion detectability was better (38% [32 of 84 rated lesions]) or the same (62% [52 of 84 rated lesions]) with MBIR as compared with 100% ASIR. Conclusion CT performed with a reduced-dose protocol and MBIR is feasible in the pediatric population, and it maintains diagnostic quality. © RSNA, 2013 Online supplemental material is available for this article. PMID:24091359

Multicenter evaluation of stress-first myocardial perfusion image triage by nuclear technologists and automated quantification.

PubMed

Chaudhry, Waseem; Hussain, Nasir; Ahlberg, Alan W; Croft, Lori B; Fernandez, Antonio B; Parker, Mathew W; Swales, Heather H; Slomka, Piotr J; Henzlova, Milena J; Duvall, W Lane

2017-06-01

A stress-first myocardial perfusion imaging (MPI) protocol saves time, is cost effective, and decreases radiation exposure. A limitation of this protocol is the requirement for physician review of the stress images to determine the need for rest images. This hurdle could be eliminated if an experienced technologist and/or automated computer quantification could make this determination. Images from consecutive patients who were undergoing a stress-first MPI with attenuation correction at two tertiary care medical centers were prospectively reviewed independently by a technologist and cardiologist blinded to clinical and stress test data. Their decision on the need for rest imaging along with automated computer quantification of perfusion results was compared with the clinical reference standard of an assessment of perfusion images by a board-certified nuclear cardiologist that included clinical and stress test data. A total of 250 patients (mean age 61 years and 55% female) who underwent a stress-first MPI were studied. According to the clinical reference standard, 42 (16.8%) and 208 (83.2%) stress-first images were interpreted as "needing" and "not needing" rest images, respectively. The technologists correctly classified 229 (91.6%) stress-first images as either "needing" (n = 28) or "not needing" (n = 201) rest images. Their sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 66.7%, 96.6%, 80.0%, and 93.5%, respectively. An automated stress TPD score ≥1.2 was associated with optimal sensitivity and specificity and correctly classified 179 (71.6%) stress-first images as either "needing" (n = 31) or "not needing" (n = 148) rest images. Its sensitivity, specificity, PPV, and NPV were 73.8%, 71.2%, 34.1%, and 93.1%, respectively. In a model whereby the computer or technologist could correct for the other's incorrect classification, 242 (96.8%) stress-first images were correctly classified. The composite sensitivity, specificity, PPV, and NPV were 83.3%, 99.5%, 97.2%, and 96.7%, respectively. Technologists and automated quantification software had a high degree of agreement with the clinical reference standard for determining the need for rest images in a stress-first imaging protocol. Utilizing an experienced technologist and automated systems to screen stress-first images could expand the use of stress-first MPI to sites where the cardiologist is not immediately available for interpretation.

Aiming for a shorter rheumatoid arthritis MRI protocol: can contrast-enhanced MRI replace T2 for the detection of bone marrow oedema?

PubMed

Stomp, Wouter; Krabben, Annemarie; van der Heijde, Désirée; Huizinga, Tom W J; Bloem, Johan L; van der Helm-van Mil, Annette H M; Reijnierse, Monique

2014-10-01

To determine whether T1 post-gadolinium chelate images (T1Gd) can replace T2-weighted images (T2) for evaluating bone marrow oedema (BME), thereby allowing a shorter magnetic resonance imaging (MRI) protocol in rheumatoid arthritis (RA). In 179 early arthritis patients and 43 advanced RA patients, wrist and metacarpophalangeal joints were examined on a 1.5-T extremity MRI system with a standard protocol (coronal T1, T2 fat-saturated and coronal and axial T1 fat-saturated after Gd). BME was scored according to OMERACT RAMRIS by two observers with and without T2 images available. Agreement was assessed using intraclass correlation coefficients (ICCs) for semi-quantitative scores and test characteristics with T2 images as reference. Agreement between scores based on T2 and T1Gd images was excellent ICC (0.80-0.99). At bone level, sensitivity and specificity of BME on T1Gd compared to T2 were high for both patient groups and both readers (all ≥80 %). T1Gd and T2 images are equally suitable for evaluating BME. Because contrast is usually administered to assess (teno)synovitis, a short MRI protocol of T1 and T1Gd is sufficient in RA. • Bone marrow oedema scores are equal on T2 and T1-Gd-chelate enhanced sequences. • Agreement between scores based on T2 and T1-Gd-chelate images was excellent. • Sensitivity and specificity for presence of bone marrow oedema were high. • A short protocol without T2 images suffices in rheumatoid arthritis patients.

Evaluating the effect of increased pitch, iterative reconstruction and dual source CT on dose reduction and image quality.

PubMed

Gariani, Joanna; Martin, Steve P; Botsikas, Diomidis; Becker, Christoph D; Montet, Xavier

2018-06-14

To compare radiation dose and image quality of thoracoabdominal scans obtained with a high-pitch protocol (pitch 3.2) and iterative reconstruction (Sinogram Affirmed Iterative Reconstruction) in comparison to standard pitch reconstructed with filtered back projection (FBP) using dual source CT. 114 CT scans (Somatom Definition Flash, Siemens Healthineers, Erlangen, Germany), 39 thoracic scans, 54 thoracoabdominal scans and 21 abdominal scans were performed. Analysis of three protocols was undertaken; pitch of 1 reconstructed with FBP, pitch of 3.2 reconstructed with SAFIRE, pitch of 3.2 with stellar detectors reconstructed with SAFIRE. Objective and subjective image analysis were performed. Dose differences of the protocols used were compared. Dose was reduced when comparing scans with a pitch of 1 reconstructed with FBP to high-pitch scans with a pitch of 3.2 reconstructed with SAFIRE with a reduction of volume CT dose index of 75% for thoracic scans, 64% for thoracoabdominal scans and 67% for abdominal scans. There was a further reduction after the implementation of stellar detectors reflected in a reduction of 36% of the dose-length product for thoracic scans. This was not at the detriment of image quality, contrast-to-noise ratio, signal-to-noise ratio and the qualitative image analysis revealed a superior image quality in the high-pitch protocols. The combination of a high pitch protocol with iterative reconstruction allows significant dose reduction in routine chest and abdominal scans whilst maintaining or improving diagnostic image quality, with a further reduction in thoracic scans with stellar detectors. Advances in knowledge: High pitch imaging with iterative reconstruction is a tool that can be used to reduce dose without sacrificing image quality.

Optimizing MRI for imaging peripheral arthritis.

PubMed

Hodgson, Richard J; O'Connor, Philip J; Ridgway, John P

2012-11-01

MRI is increasingly used for the assessment of both inflammatory arthritis and osteoarthritis. The wide variety of MRI systems in use ranges from low-field, low-cost extremity units to whole-body high-field 7-T systems, each with different strengths for specific applications. The availability of dedicated radiofrequency phased-array coils allows the rapid acquisition of high-resolution images of one or more peripheral joints. MRI is uniquely flexible in its ability to manipulate image contrast, and individual MR sequences may be combined into protocols to sensitively visualize multiple features of arthritis including synovitis, bone marrow lesions, erosions, cartilage changes, and tendinopathy. Careful choice of the imaging parameters allows images to be generated with optimal quality while minimizing unwanted artifacts. Finally, there are many novel MRI techniques that can quantify disease levels in arthritis in tissues including synovitis and cartilage. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Can Functional Brain Imaging Be Used to Explore Interactivity and Cognition in Multimedia Learning Environments?

ERIC Educational Resources Information Center

Dalgarno, Barney; Kennedy, Gregor; Bennett, Sue

2010-01-01

This paper reviews existing methods used to address questions about interactivity, cognition and learning in multimedia learning environments. Existing behavioural and self-report methods identified include observations, audit trails, questionnaires, interviews, video-stimulated recall, and think-aloud protocols. The limitations of these methods…

Diagnostic Accuracy of an MRI Protocol of the Knee Accelerated Through Parallel Imaging in Correlation to Arthroscopy.

PubMed

Schnaiter, Johannes Walter; Roemer, Frank; McKenna-Kuettner, Axel; Patzak, Hans-Joachim; May, Matthias Stefan; Janka, Rolf; Uder, Michael; Wuest, Wolfgang

2018-03-01

 Parallel imaging allows for a considerable shortening of examination times. Limited data is available about the diagnostic accuracy of an accelerated knee MRI protocol based on parallel imaging evaluating all knee joint compartments in a large patient population compared to arthroscopy.  162 consecutive patients with a knee MRI (1.5 T, Siemens Aera) and arthroscopy were included. The total MRI scan time was less than 9 minutes. Meniscus and cartilage injuries, cruciate ligament lesions, loose joint bodies and medial patellar plicae were evaluated. Sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV), as well as diagnostic accuracy were determined.  For the medial meniscus, the values were: SE 97 %, SP 88 %, PPV 94 %, and NPV 94 %. For the lateral meniscus the values were: SE 77 %, SP 99 %, PPV 98 %, and NPV 89 %. For cartilage injuries the values were: SE 72 %, SP 80 %, PPV 86 %, and NPV 61 %. For the anterior cruciate ligament the values were: SE 90 %, SP 94 %, PPV 77 %, and NPV 98 %, while all values were 100 % for the posterior cruciate ligament. For loose bodies the values were: SE 48 %, SP 96 %, PPV 62 %, and NPV 93 %, and for the medial patellar plicae the values were: SE 57 %, SP 88 %, PPV 18 %, and NPV 98 %.  A knee MRI examination with parallel imaging and a scan time of less than 9 minutes delivers reliable results with high diagnostic accuracy.   · An accelerated knee MRI protocol with parallel imaging allows for high diagnostic accuracy.. · Especially meniscal and cruciate ligament injuries are well depicted.. · Cartilage injuries seem to be overestimated.. · Schnaiter JW, Roemer F, McKenna-Kuettner A et al. Diagnostic Accuracy of an MRI Protocol of the Knee Accelerated Through Parallel Imaging in Correlation to Arthroscopy. Fortschr Röntgenstr 2018; 190: 265 - 272. © Georg Thieme Verlag KG Stuttgart · New York.

Imaging of cardiac perfusion of free-breathing small animals using dynamic phase-correlated micro-CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawall, Stefan; Kuntz, Jan; Socher, Michaela

Purpose:Mouse models of cardiac diseases have proven to be a valuable tool in preclinical research. The high cardiac and respiratory rates of free breathing mice prohibit conventional in vivo cardiac perfusion studies using computed tomography even if gating methods are applied. This makes a sacrification of the animals unavoidable and only allows for the application of ex vivo methods. Methods: To overcome this issue the authors propose a low dose scan protocol and an associated reconstruction algorithm that allows for in vivo imaging of cardiac perfusion and associated processes that are retrospectively synchronized to the respiratory and cardiac motion ofmore » the animal. The scan protocol consists of repetitive injections of contrast media within several consecutive scans while the ECG, respiratory motion, and timestamp of contrast injection are recorded and synchronized to the acquired projections. The iterative reconstruction algorithm employs a six-dimensional edge-preserving filter to provide low-noise, motion artifact-free images of the animal examined using the authors' low dose scan protocol. Results: The reconstructions obtained show that the complete temporal bolus evolution can be visualized and quantified in any desired combination of cardiac and respiratory phase including reperfusion phases. The proposed reconstruction method thereby keeps the administered radiation dose at a minimum and thus reduces metabolic inference to the animal allowing for longitudinal studies. Conclusions: The authors' low dose scan protocol and phase-correlated dynamic reconstruction algorithm allow for an easy and effective way to visualize phase-correlated perfusion processes in routine laboratory studies using free-breathing mice.« less

Whole-body computed tomography in trauma patients: optimization of the patient scanning position significantly shortens examination time while maintaining diagnostic image quality.

PubMed

Hickethier, Tilman; Mammadov, Kamal; Baeßler, Bettina; Lichtenstein, Thorsten; Hinkelbein, Jochen; Smith, Lucy; Plum, Patrick Sven; Chon, Seung-Hun; Maintz, David; Chang, De-Hua

2018-01-01

The study was conducted to compare examination time and artifact vulnerability of whole-body computed tomographies (wbCTs) for trauma patients using conventional or optimized patient positioning. Examination time was measured in 100 patients scanned with conventional protocol (Group A: arms positioned alongside the body for head and neck imaging and over the head for trunk imaging) and 100 patients scanned with optimized protocol (Group B: arms flexed on a chest pillow without repositioning). Additionally, influence of two different scanning protocols on image quality in the most relevant body regions was assessed by two blinded readers. Total wbCT duration was about 35% or 3:46 min shorter in B than in A. Artifacts in aorta (27 vs 6%), liver (40 vs 8%) and spleen (27 vs 5%) occurred significantly more often in B than in A. No incident of non-diagnostic image quality was reported, and no significant differences for lungs and spine were found. An optimized wbCT positioning protocol for trauma patients allows a significant reduction of examination time while still maintaining diagnostic image quality.

ACR/NEMA Digital Image Interface Standard (An Illustrated Protocol Overview)

NASA Astrophysics Data System (ADS)

Lawrence, G. Robert

1985-09-01

The American College of Radiologists (ACR) and the National Electrical Manufacturers Association (NEMA) have sponsored a joint standards committee mandated to develop a universal interface standard for the transfer of radiology images among a variety of PACS imaging devicesl. The resulting standard interface conforms to the ISO/OSI standard reference model for network protocol layering. The standard interface specifies the lower layers of the reference model (Physical, Data Link, Transport and Session) and implies a requirement of the Network Layer should a requirement for a network exist. The message content has been considered and a flexible message and image format specified. The following Imaging Equipment modalities are supported by the standard interface... CT Computed Tomograpy DS Digital Subtraction NM Nuclear Medicine US Ultrasound MR Magnetic Resonance DR Digital Radiology The following data types are standardized over the transmission interface media.... IMAGE DATA DIGITIZED VOICE HEADER DATA RAW DATA TEXT REPORTS GRAPHICS OTHERS This paper consists of text supporting the illustrated protocol data flow. Each layer will be individually treated. Particular emphasis will be given to the Data Link layer (Frames) and the Transport layer (Packets). The discussion utilizes a finite state sequential machine model for the protocol layers.

Image quality of mean temporal arterial and mean temporal portal venous phase images calculated from low dose dynamic volume perfusion CT datasets in patients with hepatocellular carcinoma and pancreatic cancer.

PubMed

Wang, X; Henzler, T; Gawlitza, J; Diehl, S; Wilhelm, T; Schoenberg, S O; Jin, Z Y; Xue, H D; Smakic, A

2016-11-01

Dynamic volume perfusion CT (dVPCT) provides valuable information on tissue perfusion in patients with hepatocellular carcinoma (HCC) and pancreatic cancer. However, currently dVPCT is often performed in addition to conventional CT acquisitions due to the limited morphologic image quality of dose optimized dVPCT protocols. The aim of this study was to prospectively compare objective and subjective image quality, lesion detectability and radiation dose between mean temporal arterial (mTA) and mean temporal portal venous (mTPV) images calculated from low dose dynamic volume perfusion CT (dVPCT) datasets with linearly blended 120-kVp arterial and portal venous datasets in patients with HCC and pancreatic cancer. All patients gave written informed consent for this institutional review board-approved HIPAA compliant study. 27 consecutive patients (18 men, 9 women, mean age, 69.1 years±9.4) with histologically proven HCC or suspected pancreatic cancer were prospectively enrolled. The study CT protocol included a dVPCT protocol performed with 70 or 80kVp tube voltage (18 spiral acquisitions, 71.2s total acquisition times) and standard dual-energy (90/150kVpSn) arterial and portal venous acquisition performed 25min after the dVPCT. The mTA and mTPV images were manually reconstructed from the 3 to 5 best visually selected single arterial and 3 to 5 best single portal venous phases dVPCT dataset. The linearly blended 120-kVp images were calculated from dual-energy CT (DECT) raw data. Image noise, SNR, and CNR of the liver, abdominal aorta (AA) and main portal vein (PV) were compared between the mTA/mTPV and the linearly blended 120-kVp dual-energy arterial and portal venous datasets, respectively. Subjective image quality was evaluated by two radiologists regarding subjective image noise, sharpness and overall diagnostic image quality using a 5-point Likert Scale. In addition, liver lesion detectability was performed for each liver segment by the two radiologists using the linearly blended120-kVp arterial and portal venous datasets as the reference standard. Image noise, SNR and CNR values of the mTA and mTPV were significantly higher when compared to the corresponding linearly blended arterial and portal venous 120-kVp datasets (all p<0.001) except for image noise within the PV in the portal venous phases (p=0.136). image quality of mTA and mTPV were rated significantly better when compared to the linearly blended 120-kVp arterial and portal venous datasets. Both readers were able to detect all liver lesions found on the linearly blended 120-kVp arterial and portal venous datasets using the mTA and mTPV datasets. The effective radiation dose of the dVPCT was 27.6mSv for the 80kVp protocol and 14.5mSv for the 70kVp protocol. The mean effective radiation dose for the linearly blended 120-kVp arterial and portal venous CT protocol together of the upper abdomen was 5.60mSv±1.48mSv. Our preliminary data suggest that subjective and objective image quality of mTA and mTPV datasets calculated from low-kVp dVPCT datasets is non-inferior when compared to linearly blended 120-kVp arterial and portal venous acquisitions in patients with HCC and pancreatic cancer. Thus, dVPCT could be used as a stand-alone imaging technique without additionally performed conventional arterial and portal venous CT acquisitions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Clinical Benefit of 3 Tesla Magnetic Resonance Imaging Rescanning in Patients With Focal Epilepsy and Negative 1.5 Tesla Magnetic Resonance Imaging.

PubMed

Ladino, Lady D; Balaguera, Pedro; Rascovsky, Simon; Delgado, Jorge; Llano, Juan; Hernández-Ronquillo, Lizbeth; Gómez-Arias, Bety; Téllez-Zenteno, José F

2016-01-01

Magnetic resonance imaging is an essential tool in the pre-surgical evaluation of patients with drug-resistant epilepsy. Our aim was to assess the value of re-imaging patients with focal drug-resistant epilepsy. Thirty patients with negative or non-conclusive 1.5 Tesla magnetic resonance imaging were rescanned with 1.5T and 3T. All of them had previous 1.5 scans with no seizure protocol in a non-specialized center. Two neuroradiologists who were blinded to prior imaging results randomly reviewed the magnetic resonance images. Kappa score was used to assess the reliability. Mean age of patients was 30 (SD ± 11) years. The intra-observer agreement for the first radiologist was 0.74 for 1.5T and 0.71 for 3T. In the second radiologist it was 0.82 and 0.66, respectively. Three lesions (10%) were identified by general radiologists in non-specialized centers using a 1.5T standard protocol. In our center a consensus between two neuroradiologists using epilepsy protocol identified seven lesions (23%) using 1.5T and 10 (33%) using 3T (p < 0.01). In 28% of patients this additional information resulted in a change in clinical management. 3T magnetic resonance imaging rescanning improves the diagnostic yield in patients with focal epilepsy and previous negative 1.5T magnetic resonance imaging. Use of 3T magnetic resonance imaging, epilepsy protocols, and interpretation by experienced neuroradiologists is highly recommended.

Health Insurance Portability and Accountability Act-Compliant Ocular Telehealth Network for the Remote Diagnosis and Management of Diabetic Retinopathy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yaquin; Karnowski, Thomas Paul; Tobin Jr, Kenneth William

2011-01-01

In this article, we present the design and implementation of a regional ocular telehealth network for remote assessment and management of diabetic retinopathy (DR), including the design requirements, network topology, protocol design, system work flow, graphics user interfaces, and performance evaluation. The Telemedical Retinal Image Analysis and Diagnosis Network is a computer-aided, image analysis telehealth paradigm for the diagnosis of DR and other retinal diseases using fundus images acquired from primary care end users delivering care to underserved patient populations in the mid-South and southeastern United States.

A health insurance portability and accountability act-compliant ocular telehealth network for the remote diagnosis and management of diabetic retinopathy.

PubMed

Li, Yaqin; Karnowski, Thomas P; Tobin, Kenneth W; Giancardo, Luca; Morris, Scott; Sparrow, Sylvia E; Garg, Seema; Fox, Karen; Chaum, Edward

2011-10-01

In this article, we present the design and implementation of a regional ocular telehealth network for remote assessment and management of diabetic retinopathy (DR), including the design requirements, network topology, protocol design, system work flow, graphics user interfaces, and performance evaluation. The Telemedical Retinal Image Analysis and Diagnosis Network is a computer-aided, image analysis telehealth paradigm for the diagnosis of DR and other retinal diseases using fundus images acquired from primary care end users delivering care to underserved patient populations in the mid-South and southeastern United States.

Imaging for understanding speech communication: Advances and challenges

NASA Astrophysics Data System (ADS)

Narayanan, Shrikanth

2005-04-01

Research in speech communication has relied on a variety of instrumentation methods to illuminate details of speech production and perception. One longstanding challenge has been the ability to examine real-time changes in the shaping of the vocal tract; a goal that has been furthered by imaging techniques such as ultrasound, movement tracking, and magnetic resonance imaging. The spatial and temporal resolution afforded by these techniques, however, has limited the scope of the investigations that could be carried out. In this talk, we focus on some recent advances in magnetic resonance imaging that allow us to perform near real-time investigations on the dynamics of vocal tract shaping during speech. Examples include Demolin et al. (2000) (4-5 images/second, ultra-fast turbo spin echo) and Mady et al. (2001,2002) (8 images/second, T1 fast gradient echo). A recent study by Narayanan et al. (2004) that used a spiral readout scheme to accelerate image acquisition has allowed for image reconstruction rates of 24 images/second. While these developments offer exciting prospects, a number of challenges lie ahead, including: (1) improving image acquisition protocols, hardware for enhancing signal-to-noise ratio, and optimizing spatial sampling; (2) acquiring quality synchronized audio; and (3) analyzing and modeling image data including cross-modality registration. [Work supported by NIH and NSF.

Multiple enface image averaging for enhanced optical coherence tomography angiography imaging.

PubMed

Uji, Akihito; Balasubramanian, Siva; Lei, Jianqin; Baghdasaryan, Elmira; Al-Sheikh, Mayss; Borrelli, Enrico; Sadda, SriniVas R

2018-05-31

To investigate the effect of multiple enface image averaging on image quality of the optical coherence tomography angiography (OCTA). Twenty-one normal volunteers were enrolled in this study. For each subject, one eye was imaged with 3 × 3 mm scan protocol, and another eye was imaged with the 6 × 6 mm scan protocol centred on the fovea using the ZEISS Angioplex™ spectral-domain OCTA device. Eyes were repeatedly imaged to obtain nine OCTA cube scan sets, and nine superficial capillary plexus (SCP) and deep capillary plexus (DCP) were individually averaged after registration. Eighteen eyes with a 3 × 3 mm scan field and 14 eyes with a 6 × 6 mm scan field were studied. Averaged images showed more continuous vessels and less background noise in both the SCP and the DCP as the number of frames used for averaging increased, with both 3 × 3 and 6 × 6 mm scan protocols. The intensity histogram of the vessels dramatically changed after averaging. Contrast-to-noise ratio (CNR) and subjectively assessed image quality scores also increased as the number of frames used for averaging increased in all image types. However, the additional benefit in quality diminished when averaging more than five frames. Averaging only three frames achieved significant improvement in CNR and the score assigned by certified grades. Use of multiple image averaging in OCTA enface images was found to be both objectively and subjectively effective for enhancing image quality. These findings may of value for developing optimal OCTA imaging protocols for future studies. © 2018 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Evaluating anesthetic protocols for functional blood flow imaging in the rat eye

NASA Astrophysics Data System (ADS)

Moult, Eric M.; Choi, WooJhon; Boas, David A.; Baumann, Bernhard; Clermont, Allen C.; Feener, Edward P.; Fujimoto, James G.

2017-01-01

The purpose of this study is to evaluate the suitability of five different anesthetic protocols (isoflurane, isoflurane-xylazine, pentobarbital, ketamine-xylazine, and ketamine-xylazine-vecuronium) for functional blood flow imaging in the rat eye. Total retinal blood flow was measured at a series of time points using an ultrahigh-speed Doppler OCT system. Additionally, each anesthetic protocol was qualitatively evaluated according to the following criteria: (1) time-stability of blood flow, (2) overall rate of blood flow, (3) ocular immobilization, and (4) simplicity. We observed that different anesthetic protocols produced markedly different blood flows. Different anesthetic protocols also varied with respect to the four evaluated criteria. These findings suggest that the choice of anesthetic protocol should be carefully considered when designing and interpreting functional blood flow studies in the rat eye.

SSh versus TSE sequence protocol in rapid MR examination of pediatric patients with programmable drainage system.

PubMed

Brichtová, Eva; Šenkyřík, J

2017-05-01

A low radiation burden is essential during diagnostic procedures in pediatric patients due to their high tissue sensitivity. Using MR examination instead of the routinely used CT reduces the radiation exposure and the risk of adverse stochastic effects. Our retrospective study evaluated the possibility of using ultrafast single-shot (SSh) sequences and turbo spin echo (TSE) sequences in rapid MR brain imaging in pediatric patients with hydrocephalus and a programmable ventriculoperitoneal drainage system. SSh sequences seem to be suitable for examining pediatric patients due to the speed of using this technique, but significant susceptibility artifacts due to the programmable drainage valve degrade the image quality. Therefore, a rapid MR examination protocol based on TSE sequences, less sensitive to artifacts due to ferromagnetic components, has been developed. Of 61 pediatric patients who were examined using MR and the SSh sequence protocol, a group of 15 patients with hydrocephalus and a programmable drainage system also underwent TSE sequence MR imaging. The susceptibility artifact volume in both rapid MR protocols was evaluated using a semiautomatic volumetry system. A statistically significant decrease in the susceptibility artifact volume has been demonstrated in TSE sequence imaging in comparison with SSh sequences. Using TSE sequences reduced the influence of artifacts from the programmable valve, and the image quality in all cases was rated as excellent. In all patients, rapid MR examinations were performed without any need for intravenous sedation or general anesthesia. Our study results strongly suggest the superiority of the TSE sequence MR protocol compared to the SSh sequence protocol in pediatric patients with a programmable ventriculoperitoneal drainage system due to a significant reduction of susceptibility artifact volume. Both rapid sequence MR protocols provide quick and satisfactory brain imaging with no ionizing radiation and a reduced need for intravenous or general anesthesia.

Influence of study design on digital pathology image quality evaluation: the need to define a clinical task

PubMed Central

Platiša, Ljiljana; Brantegem, Leen Van; Kumcu, Asli; Ducatelle, Richard; Philips, Wilfried

2017-01-01

Abstract. Despite the current rapid advance in technologies for whole slide imaging, there is still no scientific consensus on the recommended methodology for image quality assessment of digital pathology slides. For medical images in general, it has been recommended to assess image quality in terms of doctors’ success rates in performing a specific clinical task while using the images (clinical image quality, cIQ). However, digital pathology is a new modality, and already identifying the appropriate task is difficult. In an alternative common approach, humans are asked to do a simpler task such as rating overall image quality (perceived image quality, pIQ), but that involves the risk of nonclinically relevant findings due to an unknown relationship between the pIQ and cIQ. In this study, we explored three different experimental protocols: (1) conducting a clinical task (detecting inclusion bodies), (2) rating image similarity and preference, and (3) rating the overall image quality. Additionally, within protocol 1, overall quality ratings were also collected (task-aware pIQ). The experiments were done by diagnostic veterinary pathologists in the context of evaluating the quality of hematoxylin and eosin-stained digital pathology slides of animal tissue samples under several common image alterations: additive noise, blurring, change in gamma, change in color saturation, and JPG compression. While the size of our experiments was small and prevents drawing strong conclusions, the results suggest the need to define a clinical task. Importantly, the pIQ data collected under protocols 2 and 3 did not always rank the image alterations the same as their cIQ from protocol 1, warning against using conventional pIQ to predict cIQ. At the same time, there was a correlation between the cIQ and task-aware pIQ ratings from protocol 1, suggesting that the clinical experiment context (set by specifying the clinical task) may affect human visual attention and bring focus to their criteria of image quality. Further research is needed to assess whether and for which purposes (e.g., preclinical testing) task-aware pIQ ratings could substitute cIQ for a given clinical task. PMID:28653011

Influence of study design on digital pathology image quality evaluation: the need to define a clinical task.

PubMed

Platiša, Ljiljana; Brantegem, Leen Van; Kumcu, Asli; Ducatelle, Richard; Philips, Wilfried

2017-04-01

Despite the current rapid advance in technologies for whole slide imaging, there is still no scientific consensus on the recommended methodology for image quality assessment of digital pathology slides. For medical images in general, it has been recommended to assess image quality in terms of doctors' success rates in performing a specific clinical task while using the images (clinical image quality, cIQ). However, digital pathology is a new modality, and already identifying the appropriate task is difficult. In an alternative common approach, humans are asked to do a simpler task such as rating overall image quality (perceived image quality, pIQ), but that involves the risk of nonclinically relevant findings due to an unknown relationship between the pIQ and cIQ. In this study, we explored three different experimental protocols: (1) conducting a clinical task (detecting inclusion bodies), (2) rating image similarity and preference, and (3) rating the overall image quality. Additionally, within protocol 1, overall quality ratings were also collected (task-aware pIQ). The experiments were done by diagnostic veterinary pathologists in the context of evaluating the quality of hematoxylin and eosin-stained digital pathology slides of animal tissue samples under several common image alterations: additive noise, blurring, change in gamma, change in color saturation, and JPG compression. While the size of our experiments was small and prevents drawing strong conclusions, the results suggest the need to define a clinical task. Importantly, the pIQ data collected under protocols 2 and 3 did not always rank the image alterations the same as their cIQ from protocol 1, warning against using conventional pIQ to predict cIQ. At the same time, there was a correlation between the cIQ and task-aware pIQ ratings from protocol 1, suggesting that the clinical experiment context (set by specifying the clinical task) may affect human visual attention and bring focus to their criteria of image quality. Further research is needed to assess whether and for which purposes (e.g., preclinical testing) task-aware pIQ ratings could substitute cIQ for a given clinical task.

Dose calculation accuracy of different image value to density tables for cone-beam CT planning in head & neck and pelvic localizations.

PubMed

Barateau, Anaïs; Garlopeau, Christopher; Cugny, Audrey; De Figueiredo, Bénédicte Henriques; Dupin, Charles; Caron, Jérôme; Antoine, Mikaël

2015-03-01

We aimed to identify the most accurate combination of phantom and protocol for image value to density table (IVDT) on volume-modulated arc therapy (VMAT) dose calculation based on kV-Cone-beam CT imaging, for head and neck (H&N) and pelvic localizations. Three phantoms (Catphan(®)600, CIRS(®)062M (inner phantom for head and outer phantom for body), and TomoTherapy(®) "Cheese" phantom) were used to create IVDT curves of CBCT systems with two different CBCT protocols (Standard-dose Head and Standard Pelvis). Hounsfield Unit (HU) time stability and repeatability for a single On-Board-Imager (OBI) and compatibility of two distinct devices were assessed with Catphan(®)600. Images from the anthropomorphic phantom CIRS ATOM(®) for both CT and CBCT modalities were used for VMAT dose calculation from different IVDT curves. Dosimetric indices from CT and CBCT imaging were compared. IVDT curves from CBCT images were highly different depending on phantom used (up to 1000 HU for high densities) and protocol applied (up to 200 HU for high densities). HU time stability was verified over seven weeks. A maximum difference of 3% on the dose calculation indices studied was found between CT and CBCT VMAT dose calculation across the two localizations using appropriate IVDT curves. One IVDT curve per localization can be established with a bi-monthly verification of IVDT-CBCT. The IVDT-CBCTCIRS-Head phantom with the Standard-dose Head protocol was the most accurate combination for dose calculation on H&N CBCT images. For pelvic localizations, the IVDT-CBCTCheese established with the Standard Pelvis protocol provided the best accuracy. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

High dose microCT does not contribute towards improved microPET/CT image quantitative accuracy and can limit longitudinal scanning of small animals

NASA Astrophysics Data System (ADS)

McDougald, Wendy A.; Collins, Richard; Green, Mark; Tavares, Adriana A. S.

2017-10-01

Obtaining accurate quantitative measurements in preclinical Positron Emission Tomography/Computed Tomography (PET/CT) imaging is of paramount importance in biomedical research and helps supporting efficient translation of preclinical results to the clinic. The purpose of this study was two-fold: (1) to investigate the effects of different CT acquisition protocols on PET/CT image quality and data quantification; and (2) to evaluate the absorbed dose associated with varying CT parameters. Methods: An air/water quality control CT phantom, tissue equivalent material phantom, an in-house 3D printed phantom and an image quality PET/CT phantom were imaged using a Mediso nanoPET/CT scanner. Collected data was analyzed using PMOD software, VivoQuant software and National Electric Manufactures Association (NEMA) software implemented by Mediso. Measured Hounsfield Unit (HU) in collected CT images were compared to the known HU values and image noise was quantified. PET recovery coefficients (RC), uniformity and quantitative bias were also measured. Results: Only less than 2% and 1% of CT acquisition protocols yielded water HU values < -80 and air HU values < -840, respectively. Four out of eleven CT protocols resulted in more than 100 mGy absorbed dose. Different CT protocols did not impact PET uniformity and RC, and resulted in <4% overall bias relative to expected radioactive concentration. Conclusion: Preclinical CT protocols with increased exposure times can result in high absorbed doses to the small animals. These should be avoided, as they do not contributed towards improved microPET/CT image quantitative accuracy and could limit longitudinal scanning of small animals.

Methods for CT automatic exposure control protocol translation between scanner platforms.

PubMed

McKenney, Sarah E; Seibert, J Anthony; Lamba, Ramit; Boone, John M

2014-03-01

An imaging facility with a diverse fleet of CT scanners faces considerable challenges when propagating CT protocols with consistent image quality and patient dose across scanner makes and models. Although some protocol parameters can comfortably remain constant among scanners (eg, tube voltage, gantry rotation time), the automatic exposure control (AEC) parameter, which selects the overall mA level during tube current modulation, is difficult to match among scanners, especially from different CT manufacturers. Objective methods for converting tube current modulation protocols among CT scanners were developed. Three CT scanners were investigated, a GE LightSpeed 16 scanner, a GE VCT scanner, and a Siemens Definition AS+ scanner. Translation of the AEC parameters such as noise index and quality reference mAs across CT scanners was specifically investigated. A variable-diameter poly(methyl methacrylate) phantom was imaged on the 3 scanners using a range of AEC parameters for each scanner. The phantom consisted of 5 cylindrical sections with diameters of 13, 16, 20, 25, and 32 cm. The protocol translation scheme was based on matching either the volumetric CT dose index or image noise (in Hounsfield units) between two different CT scanners. A series of analytic fit functions, corresponding to different patient sizes (phantom diameters), were developed from the measured CT data. These functions relate the AEC metric of the reference scanner, the GE LightSpeed 16 in this case, to the AEC metric of a secondary scanner. When translating protocols between different models of CT scanners (from the GE LightSpeed 16 reference scanner to the GE VCT system), the translation functions were linear. However, a power-law function was necessary to convert the AEC functions of the GE LightSpeed 16 reference scanner to the Siemens Definition AS+ secondary scanner, because of differences in the AEC functionality designed by these two companies. Protocol translation on the basis of quantitative metrics (volumetric CT dose index or measured image noise) is feasible. Protocol translation has a dependency on patient size, especially between the GE and Siemens systems. Translation schemes that preserve dose levels may not produce identical image quality. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Workflow Dynamics and the Imaging Value Chain: Quantifying the Effect of Designating a Nonimage-Interpretive Task Workflow.

PubMed

Lee, Matthew H; Schemmel, Andrew J; Pooler, B Dustin; Hanley, Taylor; Kennedy, Tabassum A; Field, Aaron S; Wiegmann, Douglas; Yu, John-Paul J

To assess the impact of separate non-image interpretive task and image-interpretive task workflows in an academic neuroradiology practice. A prospective, randomized, observational investigation of a centralized academic neuroradiology reading room was performed. The primary reading room fellow was observed over a one-month period using a time-and-motion methodology, recording frequency and duration of tasks performed. Tasks were categorized into separate image interpretive and non-image interpretive workflows. Post-intervention observation of the primary fellow was repeated following the implementation of a consult assistant responsible for non-image interpretive tasks. Pre- and post-intervention data were compared. Following separation of image-interpretive and non-image interpretive workflows, time spent on image-interpretive tasks by the primary fellow increased from 53.8% to 73.2% while non-image interpretive tasks decreased from 20.4% to 4.4%. Mean time duration of image interpretation nearly doubled, from 05:44 to 11:01 (p = 0.002). Decreases in specific non-image interpretive tasks, including phone calls/paging (2.86/hr versus 0.80/hr), in-room consultations (1.36/hr versus 0.80/hr), and protocoling (0.99/hr versus 0.10/hr), were observed. The consult assistant experienced 29.4 task switching events per hour. Rates of specific non-image interpretive tasks for the CA were 6.41/hr for phone calls/paging, 3.60/hr for in-room consultations, and 3.83/hr for protocoling. Separating responsibilities into NIT and IIT workflows substantially increased image interpretation time and decreased TSEs for the primary fellow. Consolidation of NITs into a separate workflow may allow for more efficient task completion. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of Novel Treatment Plan Verification Techniques for Prostate Intensity Modulation Arc Therapy

DTIC Science & Technology

2010-03-01

is to develop a novel clinical useful delivered-dose verification protocol for modern prostate VMAT using Electronic Portal Imaging Device (EPID...technique. A number of important milestones have been accomplished, which include (i) calibrated CBCT HU vs. electron density curve; (ii...prostate  VMAT  using  Electronic   Portal  Imaging  Device  (EPID)  and  onboard Cone beam Computed Tomography (CBCT).  The specific aims of this project

Electronic photography at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Holm, Jack M.

1994-01-01

The field of photography began a metamorphosis several years ago which promises to fundamentally change how images are captured, transmitted, and output. At this time the metamorphosis is still in the early stages, but already new processes, hardware, and software are allowing many individuals and organizations to explore the entry of imaging into the information revolution. Exploration at this time is prerequisite to leading expertise in the future, and a number of branches at LaRC have ventured into electronic and digital imaging. Their progress until recently has been limited by two factors: the lack of an integrated approach and the lack of an electronic photographic capability. The purpose of the research conducted was to address these two items. In some respects, the lack of electronic photographs has prevented application of an integrated imaging approach. Since everything could not be electronic, the tendency was to work with hard copy. Over the summer, the Photographics Section has set up an Electronic Photography Laboratory. This laboratory now has the capability to scan film images, process the images, and output the images in a variety of forms. Future plans also include electronic capture capability. The current forms of image processing available include sharpening, noise reduction, dust removal, tone correction, color balancing, image editing, cropping, electronic separations, and halftoning. Output choices include customer specified electronic file formats which can be output on magnetic or optical disks or over the network, 4400 line photographic quality prints and transparencies to 8.5 by 11 inches, and 8000 line film negatives and transparencies to 4 by 5 inches. The problem of integrated imaging involves a number of branches at LaRC including Visual Imaging, Research Printing and Publishing, Data Visualization and Animation, Advanced Computing, and various research groups. These units must work together to develop common approaches to image processing and archiving. The ultimate goal is to be able to search for images using an on-line database and image catalog. These images could then be retrieved over the network as needed, along with information on the acquisition and processing prior to storage. For this goal to be realized, a number of standard processing protocols must be developed to allow the classification of images into categories. Standard series of processing algorithms can then be applied to each category (although many of these may be adaptive between images). Since the archived image files would be standardized, it should also be possible to develop standard output processing protocols for a number of output devices. If LaRC continues the research effort begun this summer, it may be one of the first organizations to develop an integrated approach to imaging. As such, it could serve as a model for other organizations in government and the private sector.

MDCT evaluation of potential living renal donor, prior to laparoscopic donor nephrectomy: What the transplant surgeon wants to know?

PubMed Central

Ghonge, Nitin P; Gadanayak, Satyabrat; Rajakumari, Vijaya

2014-01-01

As Laparoscopic Donor Nephrectomy (LDN) offers several advantages for the donor such as lesser post-operative pain, fewer cosmetic concerns and faster recovery time, there is growing global trend towards LDN as compared to open nephrectomy. Comprehensive pre-LDN donor evaluation includes assessment of renal morphology including pelvi-calyceal and vascular system. Apart from donor selection, evaluation of the regional anatomy allows precise surgical planning. Due to limited visualization during laparoscopic renal harvesting, detailed pre-transplant evaluation of regional anatomy, including the renal venous anatomy is of utmost importance. MDCT is the modality of choice for pre-LDN evaluation of potential renal donors. Apart from appropriate scan protocol and post-processing methods, detailed understanding of surgical techniques is essential for the Radiologist for accurate image interpretation during pre-LDN MDCT evaluation of potential renal donors. This review article describes MDCT evaluation of potential living renal donor, prior to LDN with emphasis on scan protocol, post-processing methods and image interpretation. The article laid special emphasis on surgical perspectives of pre-LDN MDCT evaluation and addresses important points which transplant surgeons want to know. PMID:25489130

Low tube voltage computed tomography urography using low-concentration contrast media: Comparison of image quality in conventional computed tomography urography.

PubMed

Hwang, Inpyeong; Cho, Jeong Yeon; Kim, Sang Youn; Oh, Seung-June; Ku, Ja Hyeon; Lee, Joongyup; Kim, Seung Hyup

2015-12-01

The aim of the present study was to investigate the feasibility and image quality of excretory CT urography performed using low iodine-concentration contrast media and low tube voltage. This prospective study enrolled 63 patients who undergoing CT urography. The subjects were randomized into two groups of an excretory phase CT urography protocol and received either 240 mg I/mL of contrast media and 80 kVp of tube voltage (low-concentration protocol, n=32) or 350 mg I/mL and 120 kVp (conventional protocol, n=31). Two readers qualitatively evaluated images for sharpness of the urinary tract, image noise, streak artifact and overall diagnostic acceptability. The mean attenuation, signal-to-noise ratio, contrast-to-noise ratio and figure of merit were measured in the urinary tract. The non-inferiority test assessed the diagnostic acceptability between the two protocol groups. The low-concentration protocol showed a significantly lower effective radiation dose (3.44 vs. 5.70 mSv, P<.001). The diagnostic acceptability was significantly lower in the low-concentration protocol with iterative reconstruction algorithm than in the conventional protocol (4.06±0.45 vs. 4.50±0.37, P<.001), however, all subjects showed at least more than standard diagnostic acceptability and the difference resided in the predefined non-inferiority margin. The signal-to-noise ratio, contrast-to-noise ratio and figure of merit were significantly higher in the low-concentration protocol along the entire urinary tract (P<.001). CT urography using 240 mg I/mL iodine contrast media, 80 kVp tube voltage and an iterative reconstruction algorithm is beneficial to reduce radiation dose and iodine load, and its objective image quality and subjective diagnostic acceptability is not inferior to that of conventional CT urography. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.

PubMed

Bolen, Michael A; Brinza, Ellen; Renapurkar, Rahul D; Kim, Esther S H; Gornik, Heather L

2017-05-01

This study sought to evaluate the diagnostic yield of a dedicated computed tomography angiography (CTA) protocol of the chest, abdomen, and pelvis in patients with fibromuscular dysplasia (FMD). FMD is an uncommon vascular disease that may result in stenosis, dissection, or aneurysm of nearly all arterial distributions, typically affecting medium-sized arteries. Findings from the United States Registry for Fibromuscular Dysplasia have suggested the potential need to perform screening imaging of the aorta and medium branch vessels. A total of 113 consecutive patients enrolled in our institutional FMD registry who received a tailored CTA protocol at our institution between March 2013 and June 2015 were included in this study. Arterial phase contrast-enhanced images were obtained on a dual-source scanner using high pitch and electrocardiogram trigger. Images were analyzed by 2 readers. Abnormalities including beading, aneurysm, dissection, and stenosis/occlusion were noted in aortic, renal, mesenteric, and iliac distributions. The most commonly affected vessels were the renal arteries (n = 76 [67%]), followed by the lower extremity/iliac arteries (n = 37 [32%]). Aortic abnormalities were less frequently encountered (n = 3 [3%]), including 1 case with mild dilation (4.2 cm) of the ascending aorta and 2 cases of dissection involving the descending aorta, 1 with mild dilation (4.4 cm). Incremental findings beyond those known at patient intake were commonly noted, including new areas of arterial beading (n = 55 [49%]), new aneurysms (n = 21 [19%]), and new dissections (n = 3 [3%]). Reformatted images were crucial, affecting final assessment in 56% of cases evaluated by reader 1 and 36% evaluated by reader 2. Screening chest, abdomen, and pelvis CTA in patients with FMD showed substantial and incremental diagnostic yield. Reformatted images should routinely be included in imaging analysis. Abnormalities in the aorta were not common, so screening of the thoracic aorta may not be indicated. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

The evolving practice of nuclear cardiology: results from the 2011 ASNC member survey.

PubMed

Tilkemeier, Peter; Green, Jacqueline; Einstein, Andrew J; Fazel, Reza; Reames, Patricia; Shaw, Leslee J

2012-12-01

Today's imaging laboratories face challenges including reimbursement, prior authorization, and accreditation standards. The impact on the practice of nuclear cardiology in the United States is unknown. We conducted a survey of ASNC members to provide a snapshot of nuclear cardiology imaging laboratories in 2011. The survey identified practice patterns including personnel, volumes, protocols used, and laboratory characteristics. We employed random sampling methodology stratified geographically. The response rate was 19.5% (73/374 laboratories). A non-random survey conducted in 2001 of 25 laboratories served as a comparator. A total of 73 laboratories, representing 202 physicians and 177 technologists responded. The reported median procedural volume was 1,225 studies annually; 88.9% of laboratories were accredited. Compared with 2001, dual isotope imaging protocol use dropped from 72% to 15.6%. Five markers of quality were surveyed. Half of laboratories use the American College of Cardiology's Appropriate Use Criteria, 61% used segmental scoring, and 32% provided guidance on post-test therapeutic management. 89% perform catheterization correlations while only 33% implemented radiation dose tracking. This survey of ASNC members provides critical information on nuclear cardiology practice to better target and service our members' needs. These data can prove invaluable to target educational needs and inform healthcare policy of contemporary nuclear cardiology practice.

Prototype development and implementation of picture archiving and communications systems based on ISO-OSI standard

NASA Astrophysics Data System (ADS)

Martinez, Ralph; Nam, Jiseung

1992-07-01

Picture Archiving and Communication Systems (PACS) is an integration of digital image formation in a hospital, which encompasses various imaging equipment, image viewing workstations, image databases, and a high speed network. The integration requires a standardization of communication protocols to connect devices from different vendors. The American College of Radiology and the National Electrical Manufacturers Association (ACR- NEMA) standard Version 2.0 provides a point-to-point hardware interface, a set of software commands, and a consistent set of data formats for PACS. But, it is inadequate for PACS networking environments, because of its point-to-point nature and its inflexibility to allow other services and protocols in the future. Based on previous experience of PACS developments in The University of Arizona, a new communication protocol for PACS networks and an approach were proposed to ACR-NEMA Working Group VI. The defined PACS protocol is intended to facilitate the development of PACS''s capable of interfacing with other hospital information systems. Also, it is intended to allow the creation of diagnostic information data bases which can be interrogated by a variety of distributed devices. A particularly important goal is to support communications in a multivendor environment. The new protocol specifications are defined primarily as a combination of the International Organization for Standardization/Open Systems Interconnection (ISO/OSI), TCP/IP protocols, and the data format portion of ACR-NEMA standard. This paper addresses the specification and implementation of the ISO-based protocol into a PACS prototype. The protocol specification, which covers Presentation, Session, Transport, and Network layers, is summarized briefly. The protocol implementation is discussed based on our implementation efforts in the UNIX Operating System Environment. At the same time, results of performance comparison between the ISO and TCP/IP implementations are presented to demonstrate the implementation of defined protocol. The testing of performance analysis is done by prototyping PACS on available platforms, which are Micro VAX II, DECstation and SUN Workstation.

Technical assessment of a cone-beam CT scanner for otolaryngology imaging: image quality, dose, and technique protocols.

PubMed

Xu, J; Reh, D D; Carey, J P; Mahesh, M; Siewerdsen, J H

2012-08-01

As cone-beam CT (CBCT) systems dedicated to various imaging specialties proliferate, technical assessment grounded in imaging physics is important to ensuring that image quality and radiation dose are quantified, understood, and justified. This paper involves technical assessment of a new CBCT scanner (CS 9300, Carestream Health, Rochester, NY) dedicated to imaging of the ear and sinuses for applications in otolaryngology-head and neck surgery (OHNS). The results guided evaluation of technique protocols to minimize radiation dose in a manner sufficient for OHNS imaging tasks. The technical assessment focused on the imaging performance and radiation dose for each of seven technique protocols recommended by the manufacturer: three sinus protocols and four ear (temporal bone) protocols. Absolute dose was measured using techniques adapted from AAPM Task Group Report No. 111, involving three stacked 16 cm diameter acrylic cylinders (CTDI phantoms) and a 0.6 cm(3) Farmer ionization chamber to measure central and peripheral dose. The central dose (D(o)) was also measured as a function of longitudinal position (z) within and beyond the primary radiation field to assess, for example, out-of-field dose to the neck. Signal-difference-to-noise ratio (SDNR) and Hounsfield unit (HU) accuracy were assessed in a commercially available quality assurance phantom (CATPHAN module CTP404, The Phantom Laboratory, Greenwich, NY) and a custom phantom with soft-tissue-simulating plastic inserts (Gammex RMI, Madison, WI). Spatial resolution was assessed both qualitatively (a line-pair pattern, CATPHAN module CTP528) and quantitatively (modulation transfer function, MTF, measured with a wire phantom). Imaging performance pertinent to various OHNS imaging tasks was qualitatively assessed using an anthropomorphic phantom as evaluated by two experienced OHNS specialists. The technical assessment motivated a variety of modifications to the manufacturer-specified protocols to provide reduced radiation dose without compromising pertinent task-based imaging performance. The revised protocols yielded D(o) ranging 2.9-5.7 mGy, representing a ∼30% reduction in dose from the original technique chart. Out-of-field dose was ∼10% of D(o) at a distance of ∼8 cm from the field edge. Soft-tissue contrast resolution was fairly limited (water-brain SDNR ∼0.4-0.7) while high-contrast performance was reasonably good (SDNR ∼2-4 for a polystyrene insert in the CATPHAN). The scanner does not demonstrate (or claim to provide) accurate HU and exhibits a systematic error in CT number that could potentially be addressed by further calibration. The spatial resolution is ∼10-16 lp∕cm as assessed in a line-pair phantom, with MTF exceeding 10% out to ∼20 lp∕cm. Qualitative assessment by expert readers suggested limited soft-tissue visibility but excellent high-contrast (bone) visualization with isotropic spatial resolution suitable to a broad spectrum of pertinent sinus and temporal bone imaging tasks. The CBCT scanner provided spatial and contrast resolution suitable to visualization of high-contrast morphology in sinus, maxillofacial, and otologic imaging applications. Rigorous technical assessment guided revision of technique protocols to reduce radiation dose while maintaining image quality sufficient for pertinent imaging tasks. The scanner appears well suited to high-contrast sinus and temporal bone imaging at doses comparable to or less than that reported for conventional diagnostic CT of the head.

Fixed-flexion knee radiography using a new positioning device produced highly repeatable measurements of joint space width: ELSA-Brasil Musculoskeletal Study (ELSA-Brasil MSK).

PubMed

Telles, Rosa Weiss; Costa-Silva, Luciana; Machado, Luciana A C; Reis, Rodrigo Citton Padilha Dos; Barreto, Sandhi Maria

To describe the performance of a non-fluoroscopic fixed-flexion PA radiographic protocol with a new positioning device, developed for the assessment of knee osteoarthritis (OA) in Brazilian Longitudinal Study of Adult Health Musculoskeletal Study (ELSA-Brasil MSK). A test-retest design including 19 adults (38 knee images) was conducted. Feasibility of the radiographic protocol was assessed by image quality parameters and presence of radioanatomic alignment according to intermargin distance (IMD) values. Repeatability was assessed for IMD and joint space width (JSW) measured at three different locations. Approximately 90% of knee images presented excellent quality. Frequencies of nearly perfect radioanatomic alignment (IMD ≤1mm) ranged from 29% to 50%, and satisfactory alignment was found in up to 71% and 76% of the images (IMD ≤1.5mm and ≤1.7mm, respectively). Repeatability analyses yielded the following results: IMD [SD of mean difference=1.08; coefficient of variation (%CV)=54.68%; intraclass correlation coefficient (ICC) (95%CI)=0.59 (0.34-0.77)]; JSW [SD of mean difference=0.34-0.61; %CV=4.48%-9.80%; ICC (95%CI)=0.74 (0.55-0.85)-0.94 (0.87-0.97)]. Adequately reproducible measurements of IMD and JSW were found in 68% and 87% of the images, respectively. Despite the difficulty in achieving consistent radioanatomic alignment between subsequent radiographs in terms of IMD, the protocol produced highly repeatable JSW measurements when these were taken at midpoint and 10mm from the medial extremity of the medial tibial plateau. Therefore, measurements of JSW at these locations can be considered adequate for the assessment of knee OA in ELSA-Brasil MSK. Copyright © 2016. Published by Elsevier Editora Ltda.

Multivoxel MR Spectroscopy in Acute Ischemic Stroke:Comparison to the Stroke Protocol MRI

PubMed Central

Dani, Krishna A.; An, Li; Henning, Erica C.; Shen, Jun; Warach, Steven

2014-01-01

Background and Purpose Few patients with stroke have been imaged with MR spectroscopy (MRS) within the first few hours after onset. We compared data from current MRI protocols to MRS in subjects with ischemic stroke. Methods MRS was incorporated into the standard clinical MRI stroke protocol for subjects <24 hours after onset. MRI and clinical correlates for the metabolic data from MRS were sought. Results One hundred thirty-six MRS voxels from 32 subjects were analyzed. Lactate preceded the appearance of the lesion on diffusion-weighted imaging in some voxels but in others lagged behind it. Current protocols may predict up to 41% of the variance of MRS metabolites. Serum glucose concentration and time to maximum partially predicted the concentration of all major metabolites. Conclusion MRS may be helpful in acute stroke, especially for lactate detection when perfusion-weighted imaging is unavailable. Current MRI protocols do provide surrogate markers for some indices of metabolic activity. PMID:23091121

TH-C-18A-06: Combined CT Image Quality and Radiation Dose Monitoring Program Based On Patient Data to Assess Consistency of Clinical Imaging Across Scanner Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christianson, O; Winslow, J; Samei, E

2014-06-15

Purpose: One of the principal challenges of clinical imaging is to achieve an ideal balance between image quality and radiation dose across multiple CT models. The number of scanners and protocols at large medical centers necessitates an automated quality assurance program to facilitate this objective. Therefore, the goal of this work was to implement an automated CT image quality and radiation dose monitoring program based on actual patient data and to use this program to assess consistency of protocols across CT scanner models. Methods: Patient CT scans are routed to a HIPPA compliant quality assurance server. CTDI, extracted using opticalmore » character recognition, and patient size, measured from the localizers, are used to calculate SSDE. A previously validated noise measurement algorithm determines the noise in uniform areas of the image across the scanned anatomy to generate a global noise level (GNL). Using this program, 2358 abdominopelvic scans acquired on three commercial CT scanners were analyzed. Median SSDE and GNL were compared across scanner models and trends in SSDE and GNL with patient size were used to determine the impact of differing automatic exposure control (AEC) algorithms. Results: There was a significant difference in both SSDE and GNL across scanner models (9–33% and 15–35% for SSDE and GNL, respectively). Adjusting all protocols to achieve the same image noise would reduce patient dose by 27–45% depending on scanner model. Additionally, differences in AEC methodologies across vendors resulted in disparate relationships of SSDE and GNL with patient size. Conclusion: The difference in noise across scanner models indicates that protocols are not optimally matched to achieve consistent image quality. Our results indicated substantial possibility for dose reduction while achieving more consistent image appearance. Finally, the difference in AEC methodologies suggests the need for size-specific CT protocols to minimize variability in image quality across CT vendors.« less

Cervical Spine Clearance in Pediatric Trauma Centers: The Need for Standardization and an Evidence-based Protocol.

PubMed

Pannu, Gurpal S; Shah, Mitesh P; Herman, Marty J

Cervical spine clearance in the pediatric trauma patient represents a particularly challenging task. Unfortunately, standardized clearance protocols for pediatric cervical clearance are poorly reported in the literature and imaging recommendations demonstrate considerable variability. With the use of a web-based survey, this study aims to define the methods utilized by pediatric trauma centers throughout North America. Specific attention was given to the identification of personnel responsible for cervical spine care, diagnostic imaging modalities used, and the presence or absence of a written pediatric cervical spine clearance protocol. A 10-question electronic survey was given to members of the newly formed Pediatric Cervical Spine Study Group, all of whom are active POSNA members. The survey was submitted via the online service SurveyMonkey (https://www.surveymonkey.com/r/7NVVQZR). The survey assessed the respondent's institution demographics, such as trauma level and services primarily responsible for consultation and operative management of cervical spine injuries. In addition, respondents were asked to identify the protocols and primary imaging modality used for cervical spine clearance. Finally, respondents were asked if their institution had a documented cervical spine clearance protocol. Of the 25 separate institutions evaluated, 21 were designated as level 1 trauma centers. Considerable variation was reported with regards to the primary service responsible for cervical spine clearance. General Surgery/Trauma (44%) is most commonly the primary service, followed by a rotating schedule (33%), Neurosugery (11%), and Orthopaedic Surgery (8%). Spine consults tend to be seen most commonly by a rotating schedule of Orthopaedic Surgery and Neurosurgery. The majority of responding institutions utilize computed tomographic imaging (46%) as the primary imaging modality, whereas 42% of hospitals used x-ray primarily. The remaining institutions reported using a combination of x-ray and computed tomographic imaging. Only 46% of institutions utilize a written, standardized pediatric cervical spine clearance protocol. This study demonstrates a striking variability in the use of personnel, imaging modalities and, most importantly, standardized protocol in the evaluation of the pediatric trauma patient with a potential cervical spine injury. Cervical spine clearance protocols have been shown to decrease the incidence of missed injuries, minimize excessive radiation exposure, decrease the time to collar removal, and lower overall associated costs. It is our opinion that development of a task force or multicenter research protocol that incorporates existing evidence-based literature is the next best step in improving the care of children with cervical spine injuries. Level 4-economic and decision analyses.

Cumulative effective dose and cancer risk for pediatric population in repetitive full spine follow-up imaging: How micro dose is the EOS microdose protocol?

PubMed

Law, Martin; Ma, Wang-Kei; Lau, Damian; Cheung, Kenneth; Ip, Janice; Yip, Lawrance; Lam, Wendy

2018-04-01

To evaluate and to obtain analytic formulation for the calculation of the effective dose and associated cancer risk using the EOS microdose protocol for scoliotic pediatric patients undergoing full spine imaging at different age of exposure; to demonstrate the microdose protocol capable of delivering lesser radiation dose and hence of further reducing cancer risk induction when compared with the EOS low dose protocol; to obtain cumulative effective dose and cancer risk for both genders scoliotic pediatrics of US and Hong Kong population using the microdose protocol. Organ absorbed doses of full spine exposed scoliotic pediatric patients have been simulated with the use of EOS microdose protocol imaging parameters input to the Monte Carlo software PCXMC. Gender and age specific effective dose has been calculated with the simulated organ absorbed dose using the ICRP-103 approach. The associated radiation induced cancer risk, expressed as lifetime attributable risk (LAR), has been estimated according to the method introduced in the Biological Effects of Ionizing Radiation VII report. Values of LAR have been estimated for scoliotic patients exposed repetitively during their follow up period at different age for US and Hong Kong population. The effective doses of full spine imaging with simultaneous posteroanterior and lateral projection for patients exposed at the age between 5 and 18 years using the EOS microdose protocol have been calculated within the range of 2.54-14.75 μSv. The corresponding LAR for US and Hong Kong population was ranged between 0.04 × 10 -6 and 0.84 × 10 -6 . Cumulative effective dose and cancer risk during follow-up period can be estimated using the results and are of information to patients and their parents. With the use of computer simulation and analytic formulation, we obtained the cumulative effective dose and cancer risk at any age of exposure for pediatric patients of US and Hong Kong population undergoing repetitive microdose protocol full spine imaging. Girls would be at a statistically significant higher cumulative cancer risk than boys undergoing the same microdose full spine imaging protocol and the same follow-up schedule. Copyright © 2018 Elsevier B.V. All rights reserved.

Specimen preparation, imaging, and analysis protocols for knife-edge scanning microscopy.

PubMed

Choe, Yoonsuck; Mayerich, David; Kwon, Jaerock; Miller, Daniel E; Sung, Chul; Chung, Ji Ryang; Huffman, Todd; Keyser, John; Abbott, Louise C

2011-12-09

Major advances in high-throughput, high-resolution, 3D microscopy techniques have enabled the acquisition of large volumes of neuroanatomical data at submicrometer resolution. One of the first such instruments producing whole-brain-scale data is the Knife-Edge Scanning Microscope (KESM), developed and hosted in the authors' lab. KESM has been used to section and image whole mouse brains at submicrometer resolution, revealing the intricate details of the neuronal networks (Golgi), vascular networks (India ink), and cell body distribution (Nissl). The use of KESM is not restricted to the mouse nor the brain. We have successfully imaged the octopus brain, mouse lung, and rat brain. We are currently working on whole zebra fish embryos. Data like these can greatly contribute to connectomics research; to microcirculation and hemodynamic research; and to stereology research by providing an exact ground-truth. In this article, we will describe the pipeline, including specimen preparation (fixing, staining, and embedding), KESM configuration and setup, sectioning and imaging with the KESM, image processing, data preparation, and data visualization and analysis. The emphasis will be on specimen preparation and visualization/analysis of obtained KESM data. We expect the detailed protocol presented in this article to help broaden the access to KESM and increase its utilization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Juffmann, Thomas; Koppell, Stewart A.; Klopfer, Brannon B.

Feynman once asked physicists to build better electron microscopes to be able to watch biology at work. While electron microscopes can now provide atomic resolution, electron beam induced specimen damage precludes high resolution imaging of sensitive materials, such as single proteins or polymers. Here, we use simulations to show that an electron microscope based on a multi-pass measurement protocol enables imaging of single proteins, without averaging structures over multiple images. While we demonstrate the method for particular imaging targets, the approach is broadly applicable and is expected to improve resolution and sensitivity for a range of electron microscopy imaging modalities,more » including, for example, scanning and spectroscopic techniques. The approach implements a quantum mechanically optimal strategy which under idealized conditions can be considered interaction-free.« less

Developing consistent Landsat data sets for large area applications: the MRLC 2001 protocol

USGS Publications Warehouse

Chander, G.; Huang, Chengquan; Yang, Limin; Homer, Collin G.; Larson, C.

2009-01-01

One of the major efforts in large area land cover mapping over the last two decades was the completion of two U.S. National Land Cover Data sets (NLCD), developed with nominal 1992 and 2001 Landsat imagery under the auspices of the MultiResolution Land Characteristics (MRLC) Consortium. Following the successful generation of NLCD 1992, a second generation MRLC initiative was launched with two primary goals: (1) to develop a consistent Landsat imagery data set for the U.S. and (2) to develop a second generation National Land Cover Database (NLCD 2001). One of the key enhancements was the formulation of an image preprocessing protocol and implementation of a consistent image processing method. The core data set of the NLCD 2001 database consists of Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images. This letter details the procedures for processing the original ETM+ images and more recent scenes added to the database. NLCD 2001 products include Anderson Level II land cover classes, percent tree canopy, and percent urban imperviousness at 30-m resolution derived from Landsat imagery. The products are freely available for download to the general public from the MRLC Consortium Web site at http://www.mrlc.gov.

Application of QC_DR software for acceptance testing and routine quality control of direct digital radiography systems: initial experiences using the Italian Association of Physicist in Medicine quality control protocol.

PubMed

Nitrosi, Andrea; Bertolini, Marco; Borasi, Giovanni; Botti, Andrea; Barani, Adriana; Rivetti, Stefano; Pierotti, Luisa

2009-12-01

Ideally, medical x-ray imaging systems should be designed to deliver maximum image quality at an acceptable radiation risk to the patient. Quality assurance procedures are employed to ensure that these standards are maintained. A quality control protocol for direct digital radiography (DDR) systems is described and discussed. Software to automatically process and analyze the required images was developed. In this paper, the initial results obtained on equipment of different DDR manufacturers were reported. The protocol was developed to highlight even small discrepancies in standard operating performance.

Poster - 10: QA of Ultrasound Images for Prostate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szpala, Stanislaw; Kohli, Kirpal S.

Purpose: The current QA protocol of ultrasound systems used in prostate brachytherapy (TG128) addresses geometrical verifications, but the scope of evaluation of image quality is limited. We recognized importance of the latter in routine practice, and designed a protocol for QA of the images. Methods: Images of an ultrasound prostate phantom (CIRS053) were collected with BK Flex Focus 400. The images were saved as bmp after adjusting the gain to 50% for consistent results. Mean pixel values and signal to noise ratio were inspected in the representative sections of the phantom, including the mock prostate and the unechoic medium. Constancymore » of these numbers over a one year period was looked at. Results: The typical intensity in the mock prostate region in the transverse images ranged between 95 and 118 (out of 256), and the signal to noise was about 10. The intensity in the urethra region was about 170±40, and the unechoic medium was 2±2. The mean and the signal to noise ratio remained almost unchanged after a year, while the signal in the unechoic medium increased to about 7±4. Similar values were obtained in the sagittal images. Conclusions: The image analysis discussed above allows quick evaluation of constancy of the image quality. This may be also useful in troubleshooting image-quality problems during routine exams, which might not be due to deterioration of the US system, but other reasons, e.g. variations in tissue properties or air being trapped between the probe and the anatomy.« less

Prospective and retrospective high order eddy current mitigation for diffusion weighted echo planar imaging.

PubMed

Xu, Dan; Maier, Joseph K; King, Kevin F; Collick, Bruce D; Wu, Gaohong; Peters, Robert D; Hinks, R Scott

2013-11-01

The proposed method is aimed at reducing eddy current (EC) induced distortion in diffusion weighted echo planar imaging, without the need to perform further image coregistration between diffusion weighted and T2 images. These ECs typically have significant high order spatial components that cannot be compensated by preemphasis. High order ECs are first calibrated at the system level in a protocol independent fashion. The resulting amplitudes and time constants of high order ECs can then be used to calculate imaging protocol specific corrections. A combined prospective and retrospective approach is proposed to apply correction during data acquisition and image reconstruction. Various phantom, brain, body, and whole body diffusion weighted images with and without the proposed method are acquired. Significantly reduced image distortion and misregistration are consistently seen in images with the proposed method compared with images without. The proposed method is a powerful (e.g., effective at 48 cm field of view and 30 cm slice coverage) and flexible (e.g., compatible with other image enhancements and arbitrary scan plane) technique to correct high order ECs induced distortion and misregistration for various diffusion weighted echo planar imaging applications, without the need for further image post processing, protocol dependent prescan, or sacrifice in signal-to-noise ratio. Copyright © 2013 Wiley Periodicals, Inc.

Environmental DNA sampling protocol - filtering water to capture DNA from aquatic organisms

USGS Publications Warehouse

Laramie, Matthew B.; Pilliod, David S.; Goldberg, Caren S.; Strickler, Katherine M.

2015-09-29

Environmental DNA (eDNA) analysis is an effective method of determining the presence of aquatic organisms such as fish, amphibians, and other taxa. This publication is meant to guide researchers and managers in the collection, concentration, and preservation of eDNA samples from lentic and lotic systems. A sampling workflow diagram and three sampling protocols are included as well as a list of suggested supplies. Protocols include filter and pump assembly using: (1) a hand-driven vacuum pump, ideal for sample collection in remote sampling locations where no electricity is available and when equipment weight is a primary concern; (2) a peristaltic pump powered by a rechargeable battery-operated driver/drill, suitable for remote sampling locations when weight consideration is less of a concern; (3) a 120-volt alternating current (AC) powered peristaltic pump suitable for any location where 120-volt AC power is accessible, or for roadside sampling locations. Images and detailed descriptions are provided for each step in the sampling and preservation process.

Automatic CT simulation optimization for radiation therapy: A general strategy.

PubMed

Li, Hua; Yu, Lifeng; Anastasio, Mark A; Chen, Hsin-Chen; Tan, Jun; Gay, Hiram; Michalski, Jeff M; Low, Daniel A; Mutic, Sasa

2014-03-01

In radiation therapy, x-ray computed tomography (CT) simulation protocol specifications should be driven by the treatment planning requirements in lieu of duplicating diagnostic CT screening protocols. The purpose of this study was to develop a general strategy that allows for automatically, prospectively, and objectively determining the optimal patient-specific CT simulation protocols based on radiation-therapy goals, namely, maintenance of contouring quality and integrity while minimizing patient CT simulation dose. The authors proposed a general prediction strategy that provides automatic optimal CT simulation protocol selection as a function of patient size and treatment planning task. The optimal protocol is the one that delivers the minimum dose required to provide a CT simulation scan that yields accurate contours. Accurate treatment plans depend on accurate contours in order to conform the dose to actual tumor and normal organ positions. An image quality index, defined to characterize how simulation scan quality affects contour delineation, was developed and used to benchmark the contouring accuracy and treatment plan quality within the predication strategy. A clinical workflow was developed to select the optimal CT simulation protocols incorporating patient size, target delineation, and radiation dose efficiency. An experimental study using an anthropomorphic pelvis phantom with added-bolus layers was used to demonstrate how the proposed prediction strategy could be implemented and how the optimal CT simulation protocols could be selected for prostate cancer patients based on patient size and treatment planning task. Clinical IMRT prostate treatment plans for seven CT scans with varied image quality indices were separately optimized and compared to verify the trace of target and organ dosimetry coverage. Based on the phantom study, the optimal image quality index for accurate manual prostate contouring was 4.4. The optimal tube potentials for patient sizes of 38, 43, 48, 53, and 58 cm were 120, 140, 140, 140, and 140 kVp, respectively, and the corresponding minimum CTDIvol for achieving the optimal image quality index 4.4 were 9.8, 32.2, 100.9, 241.4, and 274.1 mGy, respectively. For patients with lateral sizes of 43-58 cm, 120-kVp scan protocols yielded up to 165% greater radiation dose relative to 140-kVp protocols, and 140-kVp protocols always yielded a greater image quality index compared to the same dose-level 120-kVp protocols. The trace of target and organ dosimetry coverage and the γ passing rates of seven IMRT dose distribution pairs indicated the feasibility of the proposed image quality index for the predication strategy. A general strategy to predict the optimal CT simulation protocols in a flexible and quantitative way was developed that takes into account patient size, treatment planning task, and radiation dose. The experimental study indicated that the optimal CT simulation protocol and the corresponding radiation dose varied significantly for different patient sizes, contouring accuracy, and radiation treatment planning tasks.

EOS microdose protocol for the radiological follow-up of adolescent idiopathic scoliosis.

PubMed

Ilharreborde, Brice; Ferrero, Emmanuelle; Alison, Marianne; Mazda, Keyvan

2016-02-01

Imaging plays a key role in adolescent idiopathic scoliosis (AIS) to determine the prognosis and accordingly define the best therapeutic strategy to follow. Conventional radiographs with ionizing radiation have been associated with 1-2 % increased lifetime risk of developing cancer in children, and physicians, therefore, need a sensitive but harmless way to explore patients at risk, according to the "as low as reasonably achievable" concept. The EOS system (EOS imaging, Paris, France) is available in routine clinical use since 2007, and allows 3D reconstructions of the trunk in standing position with significant radiation reduction. With recent technical advances, further dose reduction can be obtained, but at the cost of image quality that might alter the reliability of 3D reconstructions. The aim of the present study was to analyze the reproducibility of a "microdose" protocol, and evaluate its use in clinical practice. 32 consecutive patients followed for AIS were prospectively included. Biplanar radiographs were obtained with the EOS system according to the new microdose protocol. From the microdose images obtained, three experienced operators performed 3D reconstructions, two times for each subject in a random order (total, 192 reconstructions). The intraoperator repeatability and interoperator reproducibility were evaluated, as recommended by the International Organization for Standardization, for the most clinically relevant 3D radiological parameters. The identification of the required anatomical landmarks for the "fast spine" reconstruction process was possible in all cases. None of the patients required a second acquisition for 3D analysis. Mean time for reconstruction was 5 ± 2 min. The intraoperator repeatability was better than interoperator reproducibility for all parameters, with values ranging between 3° and 8° for frontal and sagittal spinal parameters, and between 1° and 8° for pelvic measurements. The agreement was very good for all clinical measurements. No correlation was found between the BMI and the reliability of the measurements. Because children are notably more sensitive to the carcinogenic effects of ionizing radiation, judicious use of imaging methods and a search for newer technologies remain necessary. Results of the current study show that the new microdose acquisition protocol can be used in clinical practice without altering the quality of the images. Relevant clinical measurements can be made manually, but the landmarks are also visible enough to allow accurate 3D reconstructions (ICC >0.91 for all parameters). The resulting radiation exposure was 5.5 times lower than that received with the prior protocol, corresponding now to a 45-fold reduction compared to conventional radiographs, and can, therefore, almost be considered negligible.

Towards an improved LAI collection protocol via simulated field-based PAR sensing

DOE PAGES

Yao, Wei; Van Leeuwen, Martin; Romanczyk, Paul; ...

2016-07-14

In support of NASA’s next-generation spectrometer—the Hyperspectral Infrared Imager (HyspIRI)—we are working towards assessing sub-pixel vegetation structure from imaging spectroscopy data. Of particular interest is Leaf Area Index (LAI), which is an informative, yet notoriously challenging parameter to efficiently measure in situ. While photosynthetically-active radiation (PAR) sensors have been validated for measuring crop LAI, there is limited literature on the efficacy of PAR-based LAI measurement in the forest environment. This study (i) validates PAR-based LAI measurement in forest environments, and (ii) proposes a suitable collection protocol, which balances efficiency with measurement variation, e.g., due to sun flecks and various-sized canopymore » gaps. A synthetic PAR sensor model was developed in the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model and used to validate LAI measurement based on first-principles and explicitly-known leaf geometry. Simulated collection parameters were adjusted to empirically identify optimal collection protocols. Furthermore, these collection protocols were then validated in the field by correlating PAR-based LAI measurement to the normalized difference vegetation index (NDVI) extracted from the “classic” Airborne Visible Infrared Imaging Spectrometer (AVIRIS-C) data (R 2 was 0.61). The results indicate that our proposed collecting protocol is suitable for measuring the LAI of sparse forest (LAI < 3–5 ( m 2/m 2)).« less

Examining a New Method to Studying Velopharyngeal Structures in a Child With 22q11.2 Deletion Syndrome.

PubMed

Kollara, Lakshmi; Schenck, Graham; Jaskolka, Michael; Perry, Jamie L

2017-04-14

To date, no studies have imaged the velopharynx in children with 22q11.2 deletion syndrome (22q11.2 DS) without the use of sedation. Dysmorphology in velopharyngeal structures has been shown to have significant negative implications on speech among these individuals. This single case study was designed to assess the feasibility of a child-friendly magnetic resonance imaging (MRI) scanning protocol in this clinically challenging population and to determine the utility of this MRI protocol for future work in this area. One 6-year-old White girl diagnosed with 22q11.2 DS was imaged using a child-friendly, nonsedated MRI protocol. Quantitative and qualitative measures of the velopharyngeal area and associated structures were evaluated, and comparisons were made to age-matched control subjects with normal velopharyngeal anatomy. MRI data were successfully obtained using the child-friendly scanning protocol in the subject in the present study. Quantitative and qualitative differences of the levator muscle and associated velopharyngeal structures were noted. Using these MRI and structural analyses methods, insights related to muscle morphology can be obtained and considered as part of the research and clinical examination of children with 22q11.2 DS. The imaging protocol described in this study presents an effective means to counteract difficulties in imaging young children.

Feasibility of ultra low-dose thallium stress-redistribution protocol including prone imaging in obese patients using CZT camera.

PubMed

Kincl, Vladimír; Kamínek, Milan; Vašina, Jiří; Panovský, Roman; Havel, Martin

2016-09-01

High efficiency cadmium-zinc-telluride (CZT) cameras provide an opportunity to lower the injected activities of radiopharmaceuticals for single photon emission tomography (SPECT) myocardial perfusion imaging (MPI). The limits for reducing activities of thallium have not been determined, particularly in obese patients. After an injection of 0.7 megabecquerel (MBq) of thallium/kg, we collected an average 1.5 million counts for the 10-min acquisition in a pilot cohort of ten patients. After extrapolation, we reduced the administered activity to 0.5 MBq/kg to obtain the expected 1 million counts. We studied the image quality in 124 patients (86 men, 43 obese with body mass index over 30 kg/m 2 ) referred for MPI. The quality of images was assessed by a number of recorded counts and visually by a four-grade scale (one-poor quality, four-excellent quality). In non-obese and obese patients, the average number of recorded counts was 1.1 vs. 1.07 million counts for the 10-min stress acquisition, 1.04 vs. 1.06 million counts for the 13-min rest acquisition, and the average quality score was 3.97 vs. 3.90, respectively (p = NS).The mean administered activity was 39.2 ± 7 MBq for non-obese and 48.7 ± 6 for obese patients (p < 0.0001), and the calculated effective dose was 4.0 ± 0.7 and 4.9 ± 0.6 mSv respectively (p < 0.0001). The ultra-low-dose thallium stress-redistribution protocol, including post-stress prone imaging, provides good quality of images with a low radiation burden, even in obese patients.

Magnetic resonance angiography detection of abnormal carotid artery plaque in patients with cryptogenic stroke.

PubMed

Gupta, Ajay; Gialdini, Gino; Lerario, Michael P; Baradaran, Hediyeh; Giambrone, Ashley; Navi, Babak B; Marshall, Randolph S; Iadecola, Costantino; Kamel, Hooman

2015-06-15

Magnetic resonance imaging of carotid plaque can aid in stroke risk stratification in patients with carotid stenosis. However, the prevalence of complicated carotid plaque in patients with cryptogenic stroke is uncertain, especially as assessed by plaque imaging techniques routinely included in acute stroke magnetic resonance imaging protocols. We assessed whether the magnetic resonance angiography-defined presence of intraplaque high-intensity signal (IHIS), a marker of intraplaque hemorrhage, is associated with ipsilateral cryptogenic stroke. Cryptogenic stroke patients with magnetic resonance imaging evidence of unilateral anterior circulation infarction and without hemodynamically significant (≥50%) stenosis of the cervical carotid artery were identified from a prospective stroke registry at a tertiary-care hospital. High-risk plaque was assessed by evaluating for IHIS on routine magnetic resonance angiography source images using a validated technique. To compare the presence of IHIS on the ipsilateral versus contralateral side within individual patients, we used McNemar's test for correlated proportions. A total of 54 carotid arteries in 27 unique patients were included. A total of 6 patients (22.2%) had IHIS-positive nonstenosing carotid plaque ipsilateral to the side of ischemic stroke compared to 0 patients who had IHIS-positive carotid plaques contralateral to the side of stroke (P=0.01). Stroke severity measures, diagnostic evaluations, and prevalence of vascular risk factors were not different between the IHIS-positive and IHIS-negative groups. Our findings suggest that a proportion of strokes classified as cryptogenic may be mechanistically related to complicated, nonhemodynamically significant cervical carotid artery plaque that can easily be detected by routine magnetic resonance imaging/magnetic resonance angiography acute stroke protocols. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

A double fluorescence staining protocol to determine the cross-sectional area of myofibers using image analysis

NASA Technical Reports Server (NTRS)

Mozdziak, P. E.; Fassel, T. A.; Schultz, E.; Greaser, M. L.; Cassens, R. G.

1996-01-01

A double fluorescence staining protocol was developed to facilitate computer based image analysis. Myofibers from experimentally treated (irradiated) and control growing turkey skeletal muscle were labeled with the anti-myosin antibody MF-20 and detected using fluorescein-5-isothiocyanate (FITC). Extracellular material was stained with concanavalin A (ConA)-Texas red. The cross-sectional area of the myofibers was determined by calculating the number of pixels (0.83 mu m(2)) overlying each myofiber after subtracting the ConA-Texas red image from the MF-20-FITC image for each region of interest. As expected, myofibers in the irradiated muscle were smaller (P < 0.05) than those in the non-irradiated muscle. This double fluorescence staining protocol combined with image analysis is accurate and less labor-intensive than classical procedures for determining the cross-sectional area of myofibers.

A simple procedure to analyze positions of interest in infectious cell cultures by correlative light and electron microscopy.

PubMed

Madela, Kazimierz; Banhart, Sebastian; Zimmermann, Anja; Piesker, Janett; Bannert, Norbert; Laue, Michael

2014-01-01

Plastic cell culture dishes that contain a thin bottom of highest optical quality including an imprinted finder grid (μ-Dish Grid-500) are optimally suited for routine correlative light and electron microscopy using chemical fixation. Such dishes allow high-resolution fluorescence and bright-field imaging using fixed and living cells and are compatible with standard protocols for scanning and transmission electron microscopy. Ease of use during cell culture and imaging, as well as a tight cover render the dishes particularly suitable for working with infectious organisms up to the highest biosafety level. Detailed protocols are provided and demonstrated by showing two examples: monitoring the production of virus-like particles of the Human Endogenous Retrovirus HERV-K(HML-2) by HeLa cells and investigation of Rab11-positive membrane-compartments of HeLa cells after infection with Chlamydia trachomatis. © 2014 Elsevier Inc. All rights reserved.

Intrafraction Bladder Motion in Radiation Therapy Estimated From Pretreatment and Posttreatment Volumetric Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foroudi, Farshad, E-mail: farshad.foroudi@petermac.org; Pham, Daniel; Bressel, Mathias

2013-05-01

Purpose: The use of image guidance protocols using soft tissue anatomy identification before treatment can reduce interfractional variation. This makes intrafraction clinical target volume (CTV) to planning target volume (PTV) changes more important, including those resulting from intrafraction bladder filling and motion. The purpose of this study was to investigate the required intrafraction margins for soft tissue image guidance from pretreatment and posttreatment volumetric imaging. Methods and Materials: Fifty patients with muscle-invasive bladder cancer (T2-T4) underwent an adaptive radiation therapy protocol using daily pretreatment cone beam computed tomography (CBCT) with weekly posttreatment CBCT. A total of 235 pairs of pretreatmentmore » and posttreatment CBCT images were retrospectively contoured by a single radiation oncologist (CBCT-CTV). The maximum bladder displacement was measured according to the patient's bony pelvis movement during treatment, intrafraction bladder filling, and bladder centroid motion. Results: The mean time between pretreatment and posttreatment CBCT was 13 minutes, 52 seconds (range, 7 min 52 sec to 30 min 56 sec). Taking into account patient motion, bladder centroid motion, and bladder filling, the required margins to cover intrafraction changes from pretreatment to posttreatment in the superior, inferior, right, left, anterior, and posterior were 1.25 cm (range, 1.19-1.50 cm), 0.67 cm (range, 0.58-1.12 cm), 0.74 cm (range, 0.59-0.94 cm), 0.73 cm (range, 0.51-1.00 cm), 1.20 cm (range, 0.85-1.32 cm), and 0.86 cm (range, 0.73-0.99), respectively. Small bladders on pretreatment imaging had relatively the largest increase in pretreatment to posttreatment volume. Conclusion: Intrafraction motion of the bladder based on pretreatment and posttreatment bladder imaging can be significant particularly in the anterior and superior directions. Patient motion, bladder centroid motion, and bladder filling all contribute to changes between pretreatment and posttreatment imaging. Asymmetric expansion of CTV to PTV should be considered. Care is required in using image-guided radiation therapy protocols that reduce CTV to PTV margins based only on daily pretreatment soft tissue position.« less

Post-radiosynovectomy imaging of Er-169 using scintigraphy and autoradiography.

PubMed

Farahati, Jamshid; Elliott, Johanna; Höppner, Sabrina; Stein, Linda; Gilman, Elena; Kumm, Dietmar; Grodotzki, Thomas

2017-06-01

Currently, there is no protocol for the detection of intra-articular distribution of Er-169 citrate after radiosynovectomy. We propose post-therapeutic imaging using scintigraphy and cobalt-57 pen-marker autoradiography. This technique evaluates the efficacy of the radiosynovectomy and patient safety and could be utilized for dosimetric protocol.

Imaging Modalities Relevant to Intracranial Pressure Assessment in Astronauts: A Case-Based Discussion

NASA Technical Reports Server (NTRS)

Sargsyan, Ashot E.; Kramer, Larry A.; Hamilton, Douglas R.; Hamilton, Douglas R.; Fogarty, Jennifer; Polk, J. D.

2010-01-01

Introduction: Intracranial pressure (ICP) elevation has been inferred or documented in a number of space crewmembers. Recent advances in noninvasive imaging technology offer new possibilities for ICP assessment. Most International Space Station (ISS) partner agencies have adopted a battery of occupational health monitoring tests including magnetic resonance imaging (MRI) pre- and postflight, and high-resolution sonography of the orbital structures in all mission phases including during flight. We hypothesize that joint consideration of data from the two techniques has the potential to improve quality and continuity of crewmember monitoring and care. Methods: Specially designed MRI and sonographic protocols were used to image eyes and optic nerves (ON) including the meningeal sheaths. Specific crewmembers multi-modality imaging data were analyzed to identify points of mutual validation as well as unique features of complementary nature. Results and Conclusion: Magnetic resonance imaging (MRI) and high-resolution sonography are both tomographic methods, however images obtained by the two modalities are based on different physical phenomena and use different acquisition principles. Consideration of the images acquired by these two modalities allows cross-validating findings related to the volume and fluid content of the ON subarachnoid space, shape of the globe, and other anatomical features of the orbit. Each of the imaging modalities also has unique advantages, making them complementary techniques.

Impact of imaging approach on radiation dose and associated cancer risk in children undergoing cardiac catheterization

PubMed Central

Einstein, Andrew J.; Januzis, Natalie; Nguyen, Giao; Li, Jennifer S.; Fleming, Gregory A.; Yoshizumi, Terry K.

2016-01-01

Objectives To quantify the impact of image optimization on absorbed radiation dose and associated risk in children undergoing cardiac catheterization. Background Various imaging and fluoroscopy system technical parameters including camera magnification, source-to-image distance, collimation, anti-scatter grids, beam quality, and pulse rates, all affect radiation dose but have not been well studied in younger children. Methods We used anthropomorphic phantoms (ages: newborn and 5-years-old) to measure surface radiation exposure from various imaging approaches and estimated absorbed organ doses and effective doses (ED) using Monte Carlo simulations. Models developed in the National Academies’ Biological Effects of Ionizing Radiation VII report were used to compare an imaging protocol optimized for dose reduction versus suboptimal imaging (+20cm source-to-image-distance, +1 magnification setting, no collimation) on lifetime attributable risk (LAR) of cancer. Results For the newborn and 5-year-old phantoms respectively ED changes were as follows: +157% and +232% for an increase from 6-inch to 10-inch camera magnification; +61% and +59% for a 20cm increase in source-to-image-distance; −42% and −48% with addition of 1-inch periphery collimation; −31% and −46% with removal of the anti-scatter grid. Compared to an optimized protocol, suboptimal imaging increased ED by 2.75-fold (newborn) and 4-fold (5-year-old). Estimated cancer LAR from 30-minutes of postero-anterior fluoroscopy using optimized versus sub-optimal imaging respectively was: 0.42% versus 1.23% (newborn female), 0.20% vs 0.53% (newborn male), 0.47% versus 1.70% (5-year-old female) and 0.16% vs 0.69% (5-year-old male). Conclusions Radiation-related risks to children undergoing cardiac catheterization can be substantial but are markedly reduced with an optimized imaging approach. PMID:27315598

Impact of imaging approach on radiation dose and associated cancer risk in children undergoing cardiac catheterization.

PubMed

Hill, Kevin D; Wang, Chu; Einstein, Andrew J; Januzis, Natalie; Nguyen, Giao; Li, Jennifer S; Fleming, Gregory A; Yoshizumi, Terry K

2017-04-01

To quantify the impact of image optimization on absorbed radiation dose and associated risk in children undergoing cardiac catheterization. Various imaging and fluoroscopy system technical parameters including camera magnification, source-to-image distance, collimation, antiscatter grids, beam quality, and pulse rates, all affect radiation dose but have not been well studied in younger children. We used anthropomorphic phantoms (ages: newborn and 5 years old) to measure surface radiation exposure from various imaging approaches and estimated absorbed organ doses and effective doses (ED) using Monte Carlo simulations. Models developed in the National Academies' Biological Effects of Ionizing Radiation VII report were used to compare an imaging protocol optimized for dose reduction versus suboptimal imaging (+20 cm source-to-image-distance, +1 magnification setting, no collimation) on lifetime attributable risk (LAR) of cancer. For the newborn and 5-year-old phantoms, respectively ED changes were as follows: +157% and +232% for an increase from 6-inch to 10-inch camera magnification; +61% and +59% for a 20 cm increase in source-to-image-distance; -42% and -48% with addition of 1-inch periphery collimation; -31% and -46% with removal of the antiscatter grid. Compared with an optimized protocol, suboptimal imaging increased ED by 2.75-fold (newborn) and fourfold (5 years old). Estimated cancer LAR from 30-min of posteroanterior fluoroscopy using optimized versus suboptimal imaging, respectively was 0.42% versus 1.23% (newborn female), 0.20% versus 0.53% (newborn male), 0.47% versus 1.70% (5-year-old female) and 0.16% versus 0.69% (5-year-old male). Radiation-related risks to children undergoing cardiac catheterization can be substantial but are markedly reduced with an optimized imaging approach. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Brain Gliomas: Multicenter Standardized Assessment of Dynamic Contrast-enhanced and Dynamic Susceptibility Contrast MR Images.

PubMed

Anzalone, Nicoletta; Castellano, Antonella; Cadioli, Marcello; Conte, Gian Marco; Cuccarini, Valeria; Bizzi, Alberto; Grimaldi, Marco; Costa, Antonella; Grillea, Giovanni; Vitali, Paolo; Aquino, Domenico; Terreni, Maria Rosa; Torri, Valter; Erickson, Bradley J; Caulo, Massimo

2018-06-01

Purpose To evaluate the feasibility of a standardized protocol for acquisition and analysis of dynamic contrast material-enhanced (DCE) and dynamic susceptibility contrast (DSC) magnetic resonance (MR) imaging in a multicenter clinical setting and to verify its accuracy in predicting glioma grade according to the new World Health Organization 2016 classification. Materials and Methods The local research ethics committees of all centers approved the study, and informed consent was obtained from patients. One hundred patients with glioma were prospectively examined at 3.0 T in seven centers that performed the same preoperative MR imaging protocol, including DCE and DSC sequences. Two independent readers identified the perfusion hotspots on maps of volume transfer constant (K trans ), plasma (v p ) and extravascular-extracellular space (v e ) volumes, initial area under the concentration curve, and relative cerebral blood volume (rCBV). Differences in parameters between grades and molecular subtypes were assessed by using Kruskal-Wallis and Mann-Whitney U tests. Diagnostic accuracy was evaluated by using receiver operating characteristic curve analysis. Results The whole protocol was tolerated in all patients. Perfusion maps were successfully obtained in 94 patients. An excellent interreader reproducibility of DSC- and DCE-derived measures was found. Among DCE-derived parameters, v p and v e had the highest accuracy (are under the receiver operating characteristic curve [A z ] = 0.847 and 0.853) for glioma grading. DSC-derived rCBV had the highest accuracy (A z = 0.894), but the difference was not statistically significant (P > .05). Among lower-grade gliomas, a moderate increase in both v p and rCBV was evident in isocitrate dehydrogenase wild-type tumors, although this was not significant (P > .05). Conclusion A standardized multicenter acquisition and analysis protocol of DCE and DSC MR imaging is feasible and highly reproducible. Both techniques showed a comparable, high diagnostic accuracy for grading gliomas. © RSNA, 2018 Online supplemental material is available for this article.

In Vitro Culturing and Live Imaging of Drosophila Egg Chambers: A History and Adaptable Method.

PubMed

Peters, Nathaniel C; Berg, Celeste A

2016-01-01

The development of the Drosophila egg chamber encompasses a myriad of diverse germline and somatic events, and as such, the egg chamber has become a widely used and influential developmental model. Advantages of this system include physical accessibility, genetic tractability, and amenability to microscopy and live culturing, the last of which is the focus of this chapter. To provide adequate context, we summarize the structure of the Drosophila ovary and egg chamber, the morphogenetic events of oogenesis, the history of egg-chamber live culturing, and many of the important discoveries that this culturing has afforded. Subsequently, we discuss various culturing methods that have facilitated analyses of different stages of egg-chamber development and different types of cells within the egg chamber, and we present an optimized protocol for live culturing Drosophila egg chambers.We designed this protocol for culturing late-stage Drosophila egg chambers and live imaging epithelial tube morphogenesis, but with appropriate modifications, it can be used to culture egg chambers of any stage. The protocol employs a liquid-permeable, weighted "blanket" to gently hold egg chambers against the coverslip in a glass-bottomed culture dish so the egg chambers can be imaged on an inverted microscope. This setup provides a more buffered, stable, culturing environment than previously published methods by using a larger volume of culture media, but the setup is also compatible with small volumes. This chapter should aid researchers in their efforts to culture and live-image Drosophila egg chambers, further augmenting the impressive power of this model system.

In vitro culturing and live imaging of Drosophila egg chambers: A history and adaptable method

PubMed Central

Peters, Nathaniel C.; Berg, Celeste A.

2017-01-01

Summary/Abstract The development of the Drosophila egg chamber encompasses a myriad of diverse germline and somatic events, and as such, the egg chamber has become a widely used and influential developmental model. Advantages of this system include physical accessibility, genetic tractability, and amenability to microscopy and live culturing, the last of which is the focus of this chapter. To provide adequate context, we summarize the structure of the Drosophila ovary and egg chamber, the morphogenetic events of oogenesis, the history of egg-chamber live culturing, and many of the important discoveries that this culturing has afforded. Subsequently, we discuss various culturing methods that have facilitated analyses of different stages of egg-chamber development and different types of cells within the egg chamber, and we present an optimized protocol for live culturing Drosophila egg chambers. We designed this protocol for culturing late-stage Drosophila egg chambers and live imaging epithelial tube morphogenesis, but with appropriate modifications it can be used to culture egg chambers of any stage. The protocol employs a liquid-permeable, weighted, “blanket” to gently hold egg chambers against the coverslip in a glass-bottomed culture dish so the egg chambers can be imaged on an inverted microscope. This setup provides a more buffered, stable culturing environment than previously published methods by using a larger volume of culture media, but the setup is also compatible with small volumes. This chapter should aid researchers in their efforts to culture and live image Drosophila egg chambers, further augmenting the impressive power of this model system. PMID:27557572

Multi-modal anatomical optical coherence tomography and CT for in vivo dynamic upper airway imaging

NASA Astrophysics Data System (ADS)

Balakrishnan, Santosh; Bu, Ruofei; Price, Hillel; Zdanski, Carlton; Oldenburg, Amy L.

2017-02-01

We describe a novel, multi-modal imaging protocol for validating quantitative dynamic airway imaging performed using anatomical Optical Coherence Tomography (aOCT). The aOCT system consists of a catheter-based aOCT probe that is deployed via a bronchoscope, while a programmable ventilator is used to control airway pressure. This setup is employed on the bed of a Siemens Biograph CT system capable of performing respiratory-gated acquisitions. In this arrangement the position of the aOCT catheter may be visualized with CT to aid in co-registration. Utilizing this setup we investigate multiple respiratory pressure parameters with aOCT, and respiratory-gated CT, on both ex vivo porcine trachea and live, anesthetized pigs. This acquisition protocol has enabled real-time measurement of airway deformation with simultaneous measurement of pressure under physiologically relevant static and dynamic conditions- inspiratory peak or peak positive airway pressures of 10-40 cm H2O, and 20-30 breaths per minute for dynamic studies. We subsequently compare the airway cross sectional areas (CSA) obtained from aOCT and CT, including the change in CSA at different stages of the breathing cycle for dynamic studies, and the CSA at different peak positive airway pressures for static studies. This approach has allowed us to improve our acquisition methodology and to validate aOCT measurements of the dynamic airway for the first time. We believe that this protocol will prove invaluable for aOCT system development and greatly facilitate translation of OCT systems for airway imaging into the clinical setting.

Rinsing paired-agent model (RPAM) to quantify cell-surface receptor concentrations in topical staining applications of thick tissues

NASA Astrophysics Data System (ADS)

Xu, Xiaochun; Wang, Yu; Xiang, Jialing; Liu, Jonathan T. C.; Tichauer, Kenneth M.

2017-06-01

Conventional molecular assessment of tissue through histology, if adapted to fresh thicker samples, has the potential to enhance cancer detection in surgical margins and monitoring of 3D cell culture molecular environments. However, in thicker samples, substantial background staining is common despite repeated rinsing, which can significantly reduce image contrast. Recently, ‘paired-agent’ methods—which employ co-administration of a control (untargeted) imaging agent—have been applied to thick-sample staining applications to account for background staining. To date, these methods have included (1) a simple ratiometric method that is relatively insensitive to noise in the data but has accuracy that is dependent on the staining protocol and the characteristics of the sample; and (2) a complex paired-agent kinetic modeling method that is more accurate but is more noise-sensitive and requires a precise serial rinsing protocol. Here, a new simplified mathematical model—the rinsing paired-agent model (RPAM)—is derived and tested that offers a good balance between the previous models, is adaptable to arbitrary rinsing-imaging protocols, and does not require calibration of the imaging system. RPAM is evaluated against previous models and is validated by comparison to estimated concentrations of targeted biomarkers on the surface of 3D cell culture and tumor xenograft models. This work supports the use of RPAM as a preferable model to quantitatively analyze targeted biomarker concentrations in topically stained thick tissues, as it was found to match the accuracy of the complex paired-agent kinetic model while retaining the low noise-sensitivity characteristics of the ratiometric method.

CT vaginography: a new CT technique for imaging of upper and middle vaginal fistulas.

PubMed

Botsikas, Diomidis; Pluchino, Nicola; Kalovidouri, Anastasia; Platon, Alexandra; Montet, Xavier; Dallenbach, Patrick; Poletti, Pierre-Alexandre

2017-05-01

Different types of vaginal fistulas is a relatively uncommon condition in the Western world but very frequent in developing countries. In the past, conventional vaginography was the radiological examination of choice for exploring this condition. CT and MRI are now both used for this purpose. Our objective was to test the feasibility and to explore the potential role of a new CT imaging technique implementing vaginal introitus obstruction and opacification of the vagina with iodine contrast agent, to show patency of a fistula. We describe the technical protocol of CT-vaginography as performed in Geneva University Hospitals, including vaginal catheterization with a Foley catheter and obstruction of the introitus by inflating the balloon of the catheter. We also report three cases of patients with suspected vaginal fistula who underwent CT-vaginography. The examinations were technically successful. In one patient, it revealed the presence of fistulous pathways from the vaginal fornix along the bilateral infected surgical prostheses. In a second patient, it showed a fistula between the vagina and the necrotic cavity of a recurrent cervical cancer. In a third patient, it proved the absence of a suspected vaginal fistula. CT-vaginography is a technically feasible CT protocol that provides anatomical and functional information on clinically suspected vaginal fistulas. Advances in knowledge: After the abandon of conventional vaginography in the era of transaxial imaging, the current modalities of imaging vaginal fistulas provide excellent anatomical detail but less functional information concerning the permeability of a vaginal fistulous pathway. We propose the use of CT-vaginography, a technical protocol that we describe in detail.

Inter-laboratory comparison of the in vivo comet assay including three image analysis systems.

PubMed

Plappert-Helbig, Ulla; Guérard, Melanie

2015-12-01

To compare the extent of potential inter-laboratory variability and the influence of different comet image analysis systems, in vivo comet experiments were conducted using the genotoxicants ethyl methanesulfonate and methyl methanesulfonate. Tissue samples from the same animals were processed and analyzed-including independent slide evaluation by image analysis-in two laboratories with extensive experience in performing the comet assay. The analysis revealed low inter-laboratory experimental variability. Neither the use of different image analysis systems, nor the staining procedure of DNA (propidium iodide vs. SYBR® Gold), considerably impacted the results or sensitivity of the assay. In addition, relatively high stability of the staining intensity of propidium iodide-stained slides was found in slides that were refrigerated for over 3 months. In conclusion, following a thoroughly defined protocol and standardized routine procedures ensures that the comet assay is robust and generates comparable results between different laboratories. © 2015 Wiley Periodicals, Inc.

SU-E-J-11: Measurement of Eye Lens Dose for Varian On-Board Imaging with Different CBCT Acquisition Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deshpande, S; Dhote, D; Kumar, R

Purpose: To measure actual patient eye lens dose for different cone beam computed tomography (CBCT) acquisition protocol of Varian’s On Board Imagining (OBI) system using Optically Stimulated Luminescence (OSL) dosimeter and study the eye lens dose with patient geometry and distance of isocenter to the eye lens Methods: OSL dosimeter was used to measure eye lens dose of patient. OSL dosimeter was placed on patient forehead center during CBCT image acquisition to measure eye lens dose. For three different cone beam acquisition protocol (standard dose head, low dose head and high quality head) of Varian On-Board Imaging, eye lens dosesmore » were measured. Measured doses were correlated with patient geometry and distance between isocenter to eye lens. Results: Measured eye lens dose for standard dose head was in the range of 1.8 mGy to 3.2 mGy, for high quality head protocol dose was in range of 4.5mGy to 9.9 mGy whereas for low dose head was in the range of 0.3mGy to 0.7mGy. Dose to eye lens is depends upon position of isocenter. For posterioraly located tumor eye lens dose is less. Conclusion: From measured doses it can be concluded that by proper selection of imagining protocol and frequency of imaging, it is possible to restrict the eye lens dose below the new limit set by ICRP. However, undoubted advantages of imaging system should be counter balanced by careful consideration of imaging protocol especially for very intense imaging sequences for Adoptive Radiotherapy or IMRT.« less

Coronary CT angiography with single-source and dual-source CT: comparison of image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated protocols.

PubMed

Sabarudin, Akmal; Sun, Zhonghua; Yusof, Ahmad Khairuddin Md

2013-09-30

This study is conducted to investigate and compare image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated coronary CT angiography (CCTA) with the use of single-source CT (SSCT) and dual-source CT (DSCT). A total of 209 patients who underwent CCTA with suspected coronary artery disease scanned with SSCT (n=95) and DSCT (n=114) scanners using prospective ECG-triggered and retrospective ECG-gated protocols were recruited from two institutions. The image was assessed by two experienced observers, while quantitative assessment was performed by measuring the image noise, the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR). Effective dose was calculated using the latest published conversion coefficient factor. A total of 2087 out of 2880 coronary artery segments were assessable, with 98.0% classified as of sufficient and 2.0% as of insufficient image quality for clinical diagnosis. There was no significant difference in overall image quality between prospective ECG-triggered and retrospective gated protocols, whether it was performed with DSCT or SSCT scanners. Prospective ECG-triggered protocol was compared in terms of radiation dose calculation between DSCT (6.5 ± 2.9 mSv) and SSCT (6.2 ± 1.0 mSv) scanners and no significant difference was noted (p=0.99). However, the effective dose was significantly lower with DSCT (18.2 ± 8.3 mSv) than with SSCT (28.3 ± 7.0 mSv) in the retrospective gated protocol. Prospective ECG-triggered CCTA reduces radiation dose significantly compared to retrospective ECG-gated CCTA, while maintaining good image quality. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

A Natural Language Processing-based Model to Automate MRI Brain Protocol Selection and Prioritization.

PubMed

Brown, Andrew D; Marotta, Thomas R

2017-02-01

Incorrect imaging protocol selection can contribute to increased healthcare cost and waste. To help healthcare providers improve the quality and safety of medical imaging services, we developed and evaluated three natural language processing (NLP) models to determine whether NLP techniques could be employed to aid in clinical decision support for protocoling and prioritization of magnetic resonance imaging (MRI) brain examinations. To test the feasibility of using an NLP model to support clinical decision making for MRI brain examinations, we designed three different medical imaging prediction tasks, each with a unique outcome: selecting an examination protocol, evaluating the need for contrast administration, and determining priority. We created three models for each prediction task, each using a different classification algorithm-random forest, support vector machine, or k-nearest neighbor-to predict outcomes based on the narrative clinical indications and demographic data associated with 13,982 MRI brain examinations performed from January 1, 2013 to June 30, 2015. Test datasets were used to calculate the accuracy, sensitivity and specificity, predictive values, and the area under the curve. Our optimal results show an accuracy of 82.9%, 83.0%, and 88.2% for the protocol selection, contrast administration, and prioritization tasks, respectively, demonstrating that predictive algorithms can be used to aid in clinical decision support for examination protocoling. NLP models developed from the narrative clinical information provided by referring clinicians and demographic data are feasible methods to predict the protocol and priority of MRI brain examinations. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

A service protocol for post-processing of medical images on the mobile device

NASA Astrophysics Data System (ADS)

He, Longjun; Ming, Xing; Xu, Lang; Liu, Qian

2014-03-01

With computing capability and display size growing, the mobile device has been used as a tool to help clinicians view patient information and medical images anywhere and anytime. It is uneasy and time-consuming for transferring medical images with large data size from picture archiving and communication system to mobile client, since the wireless network is unstable and limited by bandwidth. Besides, limited by computing capability, memory and power endurance, it is hard to provide a satisfactory quality of experience for radiologists to handle some complex post-processing of medical images on the mobile device, such as real-time direct interactive three-dimensional visualization. In this work, remote rendering technology is employed to implement the post-processing of medical images instead of local rendering, and a service protocol is developed to standardize the communication between the render server and mobile client. In order to make mobile devices with different platforms be able to access post-processing of medical images, the Extensible Markup Language is taken to describe this protocol, which contains four main parts: user authentication, medical image query/ retrieval, 2D post-processing (e.g. window leveling, pixel values obtained) and 3D post-processing (e.g. maximum intensity projection, multi-planar reconstruction, curved planar reformation and direct volume rendering). And then an instance is implemented to verify the protocol. This instance can support the mobile device access post-processing of medical image services on the render server via a client application or on the web page.

SU-F-J-49: IGRT Credentialing in NCTN Trials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowenstein, J; Molineu, A; Followill, D

Purpose: To make Image Guided Radiation Therapy (IGRT) credentialing a more unified, consistent and efficient process across the entire National Clinical Trial Network (NCTN). Methods: IGRT plays a role in several advanced NCTN trials. Previously an institution had to be IGRT credentialed for each protocol. When institutions were allowed to use previous credentials for new protocols it was limited to the same disease site as the original credentialing. The credentialing was analyzed by the physics PI of the protocol. We consulted with several of these physicists to determine what is important to consider when reviewing submissions and to learn waysmore » to apply credentialing more broadly. Results: For trials open in 2016, IGRT credentialing can be simplified to cover either boney anatomy or soft tissue. This revised credentialing will cover all disease sites based on the type of anatomy, unless otherwise stated within the protocol. Institutions will submit will complete an online questionnaire about their IGRT procedures. Boney anatomy requirements will include submission of data from 2 sequential fraction of both a patient aligned with boney anatomy and pelvic patient. Soft tissue will require similar submissions for a patient aligned using soft tissue and a pelvic patient. Institutions will only be required to submit the pelvic patient once. Data should be in DICOM format and includes planning CT set, RT structure set, RT plan file, RT dose file, localization images and spatial registration file (if available). Reviews will be done by IROC-Houston staff who will continue to provide feedback to the sites. Conclusion: This revised IGRT credentialing process will bring consistency, a savings in time and effort for both the IROC Houston QA office and to those institutions wanting to be credentialed to participate in NCTN Trials. Sponsored by NIH/NCI CA10953.« less

Validity of multislice computerized tomography for diagnosis of maxillofacial fractures using an independent workstation.

PubMed

Dos Santos, Denise Takehana; Costa e Silva, Adriana Paula Andrade; Vannier, Michael Walter; Cavalcanti, Marcelo Gusmão Paraiso

2004-12-01

The purpose of this study was to demonstrate the sensitivity and specificity of multislice computerized tomography (CT) for diagnosis of maxillofacial fractures following specific protocols using an independent workstation. The study population consisted of 56 patients with maxillofacial fractures who were submitted to a multislice CT. The original data were transferred to an independent workstation using volumetric imaging software to generate axial images and simultaneous multiplanar (MPR) and 3-dimensional (3D-CT) volume rendering reconstructed images. The images were then processed and interpreted by 2 examiners using the following protocols independently of each other: axial, MPR/axial, 3D-CT images, and the association of axial/MPR/3D images. The clinical/surgical findings were considered the gold standard corroborating the diagnosis of the fractures and their anatomic localization. The statistical analysis was carried out using validity and chi-squared tests. The association of axial/MPR/3D images indicated a higher sensitivity (range 95.8%) and specificity (range 99%) than the other methods regarding the analysis of all regions. CT imaging demonstrated high specificity and sensitivity for maxillofacial fractures. The association of axial/MPR/3D-CT images added important information in relationship to other CT protocols.

Standardizing Quality Assessment of Fused Remotely Sensed Images

NASA Astrophysics Data System (ADS)

Pohl, C.; Moellmann, J.; Fries, K.

2017-09-01

The multitude of available operational remote sensing satellites led to the development of many image fusion techniques to provide high spatial, spectral and temporal resolution images. The comparison of different techniques is necessary to obtain an optimized image for the different applications of remote sensing. There are two approaches in assessing image quality: 1. Quantitatively by visual interpretation and 2. Quantitatively using image quality indices. However an objective comparison is difficult due to the fact that a visual assessment is always subject and a quantitative assessment is done by different criteria. Depending on the criteria and indices the result varies. Therefore it is necessary to standardize both processes (qualitative and quantitative assessment) in order to allow an objective image fusion quality evaluation. Various studies have been conducted at the University of Osnabrueck (UOS) to establish a standardized process to objectively compare fused image quality. First established image fusion quality assessment protocols, i.e. Quality with No Reference (QNR) and Khan's protocol, were compared on varies fusion experiments. Second the process of visual quality assessment was structured and standardized with the aim to provide an evaluation protocol. This manuscript reports on the results of the comparison and provides recommendations for future research.

Standardized food images: A photographing protocol and image database.

PubMed

Charbonnier, Lisette; van Meer, Floor; van der Laan, Laura N; Viergever, Max A; Smeets, Paul A M

2016-01-01

The regulation of food intake has gained much research interest because of the current obesity epidemic. For research purposes, food images are a good and convenient alternative for real food because many dietary decisions are made based on the sight of foods. Food pictures are assumed to elicit anticipatory responses similar to real foods because of learned associations between visual food characteristics and post-ingestive consequences. In contemporary food science, a wide variety of images are used which introduces between-study variability and hampers comparison and meta-analysis of results. Therefore, we created an easy-to-use photographing protocol which enables researchers to generate high resolution food images appropriate for their study objective and population. In addition, we provide a high quality standardized picture set which was characterized in seven European countries. With the use of this photographing protocol a large number of food images were created. Of these images, 80 were selected based on their recognizability in Scotland, Greece and The Netherlands. We collected image characteristics such as liking, perceived calories and/or perceived healthiness ratings from 449 adults and 191 children. The majority of the foods were recognized and liked at all sites. The differences in liking ratings, perceived calories and perceived healthiness between sites were minimal. Furthermore, perceived caloric content and healthiness ratings correlated strongly (r ≥ 0.8) with actual caloric content in both adults and children. The photographing protocol as well as the images and the data are freely available for research use on http://nutritionalneuroscience.eu/. By providing the research community with standardized images and the tools to create their own, comparability between studies will be improved and a head-start is made for a world-wide standardized food image database. Copyright © 2015 Elsevier Ltd. All rights reserved.

A BMI-adjusted ultra-low-dose CT angiography protocol for the peripheral arteries-Image quality, diagnostic accuracy and radiation exposure.

PubMed

Schreiner, Markus M; Platzgummer, Hannes; Unterhumer, Sylvia; Weber, Michael; Mistelbauer, Gabriel; Loewe, Christian; Schernthaner, Ruediger E

2017-08-01

To investigate radiation exposure, objective image quality, and the diagnostic accuracy of a BMI-adjusted ultra-low-dose CT angiography (CTA) protocol for the assessment of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the standard of reference. In this prospective, IRB-approved study, 40 PAD patients (30 male, mean age 72 years) underwent CTA on a dual-source CT scanner at 80kV tube voltage. The reference amplitude for tube current modulation was personalized based on the body mass index (BMI) with 120 mAs for [BMI≤25] or 150 mAs for [2570%) was assessed by two readers independently and compared to subsequent DSA. Radiation exposure was assessed with the computed tomography dose index (CTDIvol) and the dosis-length product (DLP). Objective image quality was assessed via contrast- and signal-to-noise ratio (CNR and SNR) measurements. Radiation exposure and image quality were compared between the BMI groups and between the BMI-adjusted ultra-low-dose protocol and the low-dose institutional standard protocol (ISP). The BMI-adjusted ultra-low-dose protocol reached high diagnostic accuracy values of 94% for Reader 1 and 93% for Reader 2. Moreover, in comparison to the ISP, it showed significantly (p<0.001) lower CTDIvol (1.97±0.55mGy vs. 4.18±0.62 mGy) and DLP (256±81mGy x cm vs. 544±83mGy x cm) but similar image quality (p=0.37 for CNR). Furthermore, image quality was similar between BMI groups (p=0.86 for CNR). A CT protocol that incorporates low kV settings with a personalized (BMI-adjusted) reference amplitude for tube current modulation and iterative reconstruction enables very low radiation exposure CTA, while maintaining good image quality and high diagnostic accuracy in the assessment of PAD. Copyright © 2017 Elsevier B.V. All rights reserved.

Dynamic helical computed tomography of the pituitary gland in healthy dogs.

PubMed

Van der Vlugt-Meijer, Roselinda H; Meij, Björn P; Voorhout, George

2007-01-01

Dynamic helical computed tomography (CT) of the pituitary gland can be used to image the three-dimensional shape and dimensions of abnormalities within the pituitary gland. The aim of this study was to develop a protocol for dynamic helical CT of the pituitary gland in healthy dogs as a future reference study for patients with pituitary disease. Dynamic helical series of nine scans of the pituitary gland during and following contrast medium injection were performed in six healthy dogs using the following protocols: a series with 1 mm collimation and a table feed per X-ray tube rotation of 2 mm (pitch of 2) in six dogs, a series with 2 mm collimation and pitch of 2 in three dogs, and a series with 1 mm collimation and pitch of 1 in three other dogs. Multiplanar reconstructions of the images were made using a reconstruction index of 0.5. Images of all series were assessed visually for enhancement of the arteries, the neurohypophysis, and the adenohypophysis. The enhancement pattern of the neurohypophysis was distinguished adequately from that of the adenohypophysis in five dogs that were scanned with 1 mm collimation and pitch of 2, but the difference was less discernable when the other protocols were used. The carotid artery, its trifurcation, and the arterial cerebral circle were best visualized in dorsal reconstructions. Dynamic helical CT of the pituitary gland in healthy dogs can be performed with 1 mm collimation and pitch of 2, and a scan length that includes the entire pituitary region. Using this protocol, with the specific scanner used, the neurohypophysis, the adenohypophysis, and the surrounding vascular structures are adequately visualized.

Full dose reduction potential of statistical iterative reconstruction for head CT protocols in a predominantly pediatric population

PubMed Central

Mirro, Amy E.; Brady, Samuel L.; Kaufman, Robert. A.

2016-01-01

Purpose To implement the maximum level of statistical iterative reconstruction that can be used to establish dose-reduced head CT protocols in a primarily pediatric population. Methods Select head examinations (brain, orbits, sinus, maxilla and temporal bones) were investigated. Dose-reduced head protocols using an adaptive statistical iterative reconstruction (ASiR) were compared for image quality with the original filtered back projection (FBP) reconstructed protocols in phantom using the following metrics: image noise frequency (change in perceived appearance of noise texture), image noise magnitude, contrast-to-noise ratio (CNR), and spatial resolution. Dose reduction estimates were based on computed tomography dose index (CTDIvol) values. Patient CTDIvol and image noise magnitude were assessed in 737 pre and post dose reduced examinations. Results Image noise texture was acceptable up to 60% ASiR for Soft reconstruction kernel (at both 100 and 120 kVp), and up to 40% ASiR for Standard reconstruction kernel. Implementation of 40% and 60% ASiR led to an average reduction in CTDIvol of 43% for brain, 41% for orbits, 30% maxilla, 43% for sinus, and 42% for temporal bone protocols for patients between 1 month and 26 years, while maintaining an average noise magnitude difference of 0.1% (range: −3% to 5%), improving CNR of low contrast soft tissue targets, and improving spatial resolution of high contrast bony anatomy, as compared to FBP. Conclusion The methodology in this study demonstrates a methodology for maximizing patient dose reduction and maintaining image quality using statistical iterative reconstruction for a primarily pediatric population undergoing head CT examination. PMID:27056425

Multicenter evaluation of stress-first myocardial perfusion image triage by nuclear technologists and automated quantification

PubMed Central

Chaudhry, Waseem; Hussain, Nasir; Ahlberg, Alan W.; Croft, Lori B.; Fernandez, Antonio B.; Parker, Mathew W.; Swales, Heather H.; Slomka, Piotr J.; Henzlova, Milena J.; Duvall, W. Lane

2016-01-01

Background A stress-first myocardial perfusion imaging (MPI) protocol saves time, is cost effective, and decreases radiation exposure. A limitation of this protocol is the requirement for physician review of the stress images to determine the need for rest images. This hurdle could be eliminated if an experienced technologist and/or automated computer quantification could make this determination. Methods Images from consecutive patients who were undergoing a stress-first MPI with attenuation correction at two tertiary care medical centers were prospectively reviewed independently by a technologist and cardiologist blinded to clinical and stress test data. Their decision on the need for rest imaging along with automated computer quantification of perfusion results was compared with the clinical reference standard of an assessment of perfusion images by a board-certified nuclear cardiologist that included clinical and stress test data. Results A total of 250 patients (mean age 61 years and 55% female) who underwent a stress-first MPI were studied. According to the clinical reference standard, 42 (16.8%) and 208 (83.2%) stress-first images were interpreted as “needing” and “not needing” rest images, respectively. The technologists correctly classified 229 (91.6%) stress-first images as either “needing” (n = 28) or “not needing” (n = 201) rest images. Their sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 66.7%, 96.6%, 80.0%, and 93.5%, respectively. An automated stress TPD score ≥1.2 was associated with optimal sensitivity and specificity and correctly classified 179 (71.6%) stress-first images as either “needing” (n = 31) or “not needing” (n = 148) rest images. Its sensitivity, specificity, PPV, and NPV were 73.8%, 71.2%, 34.1%, and 93.1%, respectively. In a model whereby the computer or technologist could correct for the other's incorrect classification, 242 (96.8%) stress-first images were correctly classified. The composite sensitivity, specificity, PPV, and NPV were 83.3%, 99.5%, 97.2%, and 96.7%, respectively. Conclusion Technologists and automated quantification software had a high degree of agreement with the clinical reference standard for determining the need for rest images in a stress-first imaging protocol. Utilizing an experienced technologist and automated systems to screen stress-first images could expand the use of stress-first MPI to sites where the cardiologist is not immediately available for interpretation. PMID:26566774

Image registration for a UV-Visible dual-band imaging system

NASA Astrophysics Data System (ADS)

Chen, Tao; Yuan, Shuang; Li, Jianping; Xing, Sheng; Zhang, Honglong; Dong, Yuming; Chen, Liangpei; Liu, Peng; Jiao, Guohua

2018-06-01

The detection of corona discharge is an effective way for early fault diagnosis of power equipment. UV-Visible dual-band imaging can detect and locate corona discharge spot at all-weather condition. In this study, we introduce an image registration protocol for this dual-band imaging system. The protocol consists of UV image denoising and affine transformation model establishment. We report the algorithm details of UV image preprocessing, affine transformation model establishment and relevant experiments for verification of their feasibility. The denoising algorithm was based on a correlation operation between raw UV images, a continuous mask and the transformation model was established by using corner feature and a statistical method. Finally, an image fusion test was carried out to verify the accuracy of affine transformation model. It has proved the average position displacement error between corona discharge and equipment fault at different distances in a 2.5m-20 m range are 1.34 mm and 1.92 mm in the horizontal and vertical directions, respectively, which are precise enough for most industrial applications. The resultant protocol is not only expected to improve the efficiency and accuracy of such imaging system for locating corona discharge spot, but also supposed to provide a more generalized reference for the calibration of various dual-band imaging systems in practice.

Validity of linear measurements of the jaws using ultralow-dose MDCT and the iterative techniques of ASIR and MBIR.

PubMed

Al-Ekrish, Asma'a A; Al-Shawaf, Reema; Schullian, Peter; Al-Sadhan, Ra'ed; Hörmann, Romed; Widmann, Gerlig

2016-10-01

To assess the comparability of linear measurements of dental implant sites recorded from multidetector computed tomography (MDCT) images obtained using standard-dose filtered backprojection (FBP) technique with those from various ultralow doses combined with FBP, adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR) techniques. The results of the study may contribute to MDCT dose optimization for dental implant site imaging. MDCT scans of two cadavers were acquired using a standard reference protocol and four ultralow-dose test protocols (TP). The volume CT dose index of the different dose protocols ranged from a maximum of 30.48-36.71 mGy to a minimum of 0.44-0.53 mGy. All scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Linear measurements were recorded from standardized images of the jaws by two examiners. Intra- and inter-examiner reliability of the measurements were analyzed using Cronbach's alpha and inter-item correlation. Agreement between the measurements obtained with the reference-dose/FBP protocol and each of the test protocols was determined with Bland-Altman plots and linear regression. Statistical significance was set at a P-value of 0.05. No systematic variation was found between the linear measurements obtained with the reference protocol and the other imaging protocols. The only exceptions were TP3/ASIR-50 (bone kernel) and TP4/ASIR-100 (bone and standard kernels). The mean measurement differences between these three protocols and the reference protocol were within ±0.1 mm, with the 95 % confidence interval limits being within the range of ±1.15 mm. A nearly 97.5 % reduction in dose did not significantly affect the height and width measurements of edentulous jaws regardless of the reconstruction algorithm used.

OARSI Clinical Trials Recommendations: Hand imaging in clinical trials in osteoarthritis.

PubMed

Hunter, D J; Arden, N; Cicuttini, F; Crema, M D; Dardzinski, B; Duryea, J; Guermazi, A; Haugen, I K; Kloppenburg, M; Maheu, E; Miller, C G; Martel-Pelletier, J; Ochoa-Albíztegui, R E; Pelletier, J-P; Peterfy, C; Roemer, F; Gold, G E

2015-05-01

Tremendous advances have occurred in our understanding of the pathogenesis of hand osteoarthritis (OA) and these are beginning to be applied to trials targeted at modification of the disease course. The purpose of this expert opinion, consensus driven exercise is to provide detail on how one might use and apply hand imaging assessments in disease modifying clinical trials. It includes information on acquisition methods/techniques (including guidance on positioning for radiography, sequence/protocol recommendations/hardware for MRI); commonly encountered problems (including positioning, hardware and coil failures, sequences artifacts); quality assurance/control procedures; measurement methods; measurement performance (reliability, responsiveness, validity); recommendations for trials; and research recommendations. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Development of a method for measuring femoral torsion using real-time ultrasound.

PubMed

Hafiz, Eliza; Hiller, Claire E; Nicholson, Leslie L; Nightingale, E Jean; Clarke, Jillian L; Grimaldi, Alison; Eisenhuth, John P; Refshauge, Kathryn M

2014-07-01

Excessive femoral torsion has been associated with various musculoskeletal and neurological problems. To explore this relationship, it is essential to be able to measure femoral torsion in the clinic accurately. Computerized tomography (CT) and magnetic resonance imaging (MRI) are thought to provide the most accurate measurements but CT involves significant radiation exposure and MRI is expensive. The aim of this study was to design a method for measuring femoral torsion in the clinic, and to determine the reliability of this method. Details of design process, including construction of a jig, the protocol developed and the reliability of the method are presented. The protocol developed used ultrasound to image a ridge on the greater trochanter, and a customized jig placed on the femoral condyles as reference points. An inclinometer attached to the customized jig allowed quantification of the degree of femoral torsion. Measurements taken with this protocol had excellent intra- and inter-rater reliability (ICC2,1 = 0.98 and 0.97, respectively). This method of measuring femoral torsion also permitted measurement of femoral torsion with a high degree of accuracy. This method is applicable to the research setting and, with minor adjustments, will be applicable to the clinical setting.

Effectiveness of cognitive behavioral therapy supported by virtual reality in the treatment of body image in eating disorders: one year follow-up.

PubMed

Marco, José H; Perpiñá, Conxa; Botella, Cristina

2013-10-30

Body image disturbance is a significant maintenance and prognosis factor in eating disorders. Hence, existing eating disorder treatments can benefit from direct intervention in patients' body image. No controlled studies have yet compared eating disorder treatments with and without a treatment component centered on body image. This paper includes a controlled study comparing Cognitive Behavioral Treatment (CBT) for eating disorders with and without a component for body image treatment using Virtual Reality techniques. Thirty-four participants diagnosed with eating disorders were evaluated and treated. The clinical improvement was analyzed from statistical and clinical points of view. Results showed that the patients who received the component for body image treatment improved more than the group without this component. Furthermore, improvement was maintained in post-treatment and at one year follow-up. The results reveal the advantage of including a treatment component addressing body image disturbances in the protocol for general treatment of eating disorders. The implications and limitations of these results are discussed below. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Multimode C-arm fluoroscopy, tomosynthesis, and cone-beam CT for image-guided interventions: from proof of principle to patient protocols

NASA Astrophysics Data System (ADS)

Siewerdsen, J. H.; Daly, M. J.; Bachar, G.; Moseley, D. J.; Bootsma, G.; Brock, K. K.; Ansell, S.; Wilson, G. A.; Chhabra, S.; Jaffray, D. A.; Irish, J. C.

2007-03-01

High-performance intraoperative imaging is essential to an ever-expanding scope of therapeutic procedures ranging from tumor surgery to interventional radiology. The need for precise visualization of bony and soft-tissue structures with minimal obstruction to the therapy setup presents challenges and opportunities in the development of novel imaging technologies specifically for image-guided procedures. Over the past ~5 years, a mobile C-arm has been modified in collaboration with Siemens Medical Solutions for 3D imaging. Based upon a Siemens PowerMobil, the device includes: a flat-panel detector (Varian PaxScan 4030CB); a motorized orbit; a system for geometric calibration; integration with real-time tracking and navigation (NDI Polaris); and a computer control system for multi-mode fluoroscopy, tomosynthesis, and cone-beam CT. Investigation of 3D imaging performance (noise-equivalent quanta), image quality (human observer studies), and image artifacts (scatter, truncation, and cone-beam artifacts) has driven the development of imaging techniques appropriate to a host of image-guided interventions. Multi-mode functionality presents a valuable spectrum of acquisition techniques: i.) fluoroscopy for real-time 2D guidance; ii.) limited-angle tomosynthesis for fast 3D imaging (e.g., ~10 sec acquisition of coronal slices containing the surgical target); and iii.) fully 3D cone-beam CT (e.g., ~30-60 sec acquisition providing bony and soft-tissue visualization across the field of view). Phantom and cadaver studies clearly indicate the potential for improved surgical performance - up to a factor of 2 increase in challenging surgical target excisions. The C-arm system is currently being deployed in patient protocols ranging from brachytherapy to chest, breast, spine, and head and neck surgery.

Live-Cell Imaging of Mitochondria and the Actin Cytoskeleton in Budding Yeast.

PubMed

Higuchi-Sanabria, Ryo; Swayne, Theresa C; Boldogh, Istvan R; Pon, Liza A

2016-01-01

Maintenance and regulation of proper mitochondrial dynamics and functions are necessary for cellular homeostasis. Numerous diseases, including neurodegeneration and muscle myopathies, and overall cellular aging are marked by declining mitochondrial function and subsequent loss of multiple other cellular functions. For these reasons, optimized protocols are needed for visualization and quantification of mitochondria and their function and fitness. In budding yeast, mitochondria are intimately associated with the actin cytoskeleton and utilize actin for their movement and inheritance. This chapter describes optimal approaches for labeling mitochondria and the actin cytoskeleton in living budding yeast cells, for imaging the labeled cells, and for analyzing the resulting images.

A Health Insurance Portability and Accountability Act–Compliant Ocular Telehealth Network for the Remote Diagnosis and Management of Diabetic Retinopathy

PubMed Central

Li, Yaqin; Karnowski, Thomas P.; Tobin, Kenneth W.; Giancardo, Luca; Morris, Scott; Sparrow, Sylvia E.; Garg, Seema; Fox, Karen

2011-01-01

Abstract In this article, we present the design and implementation of a regional ocular telehealth network for remote assessment and management of diabetic retinopathy (DR), including the design requirements, network topology, protocol design, system work flow, graphics user interfaces, and performance evaluation. The Telemedical Retinal Image Analysis and Diagnosis Network is a computer-aided, image analysis telehealth paradigm for the diagnosis of DR and other retinal diseases using fundus images acquired from primary care end users delivering care to underserved patient populations in the mid-South and southeastern United States. PMID:21819244

A standardised protocol for texture feature analysis of endoscopic images in gynaecological cancer.

PubMed

Neofytou, Marios S; Tanos, Vasilis; Pattichis, Marios S; Pattichis, Constantinos S; Kyriacou, Efthyvoulos C; Koutsouris, Dimitris D

2007-11-29

In the development of tissue classification methods, classifiers rely on significant differences between texture features extracted from normal and abnormal regions. Yet, significant differences can arise due to variations in the image acquisition method. For endoscopic imaging of the endometrium, we propose a standardized image acquisition protocol to eliminate significant statistical differences due to variations in: (i) the distance from the tissue (panoramic vs close up), (ii) difference in viewing angles and (iii) color correction. We investigate texture feature variability for a variety of targets encountered in clinical endoscopy. All images were captured at clinically optimum illumination and focus using 720 x 576 pixels and 24 bits color for: (i) a variety of testing targets from a color palette with a known color distribution, (ii) different viewing angles, (iv) two different distances from a calf endometrial and from a chicken cavity. Also, human images from the endometrium were captured and analysed. For texture feature analysis, three different sets were considered: (i) Statistical Features (SF), (ii) Spatial Gray Level Dependence Matrices (SGLDM), and (iii) Gray Level Difference Statistics (GLDS). All images were gamma corrected and the extracted texture feature values were compared against the texture feature values extracted from the uncorrected images. Statistical tests were applied to compare images from different viewing conditions so as to determine any significant differences. For the proposed acquisition procedure, results indicate that there is no significant difference in texture features between the panoramic and close up views and between angles. For a calibrated target image, gamma correction provided an acquired image that was a significantly better approximation to the original target image. In turn, this implies that the texture features extracted from the corrected images provided for better approximations to the original images. Within the proposed protocol, for human ROIs, we have found that there is a large number of texture features that showed significant differences between normal and abnormal endometrium. This study provides a standardized protocol for avoiding any significant texture feature differences that may arise due to variability in the acquisition procedure or the lack of color correction. After applying the protocol, we have found that significant differences in texture features will only be due to the fact that the features were extracted from different types of tissue (normal vs abnormal).

Evaluation of a continuous-rotation, high-speed scanning protocol for micro-computed tomography.

PubMed

Kerl, Hans Ulrich; Isaza, Cristina T; Boll, Hanne; Schambach, Sebastian J; Nolte, Ingo S; Groden, Christoph; Brockmann, Marc A

2011-01-01

Micro-computed tomography is used frequently in preclinical in vivo research. Limiting factors are radiation dose and long scan times. The purpose of the study was to compare a standard step-and-shoot to a continuous-rotation, high-speed scanning protocol. Micro-computed tomography of a lead grid phantom and a rat femur was performed using a step-and-shoot and a continuous-rotation protocol. Detail discriminability and image quality were assessed by 3 radiologists. The signal-to-noise ratio and the modulation transfer function were calculated, and volumetric analyses of the femur were performed. The radiation dose of the scan protocols was measured using thermoluminescence dosimeters. The 40-second continuous-rotation protocol allowed a detail discriminability comparable to the step-and-shoot protocol at significantly lower radiation doses. No marked differences in volumetric or qualitative analyses were observed. Continuous-rotation micro-computed tomography significantly reduces scanning time and radiation dose without relevantly reducing image quality compared with a normal step-and-shoot protocol.

Real-Time QoS Routing Protocols in Wireless Multimedia Sensor Networks: Study and Analysis.

PubMed

Alanazi, Adwan; Elleithy, Khaled

2015-09-02

Many routing protocols have been proposed for wireless sensor networks. These routing protocols are almost always based on energy efficiency. However, recent advances in complementary metal-oxide semiconductor (CMOS) cameras and small microphones have led to the development of Wireless Multimedia Sensor Networks (WMSN) as a class of wireless sensor networks which pose additional challenges. The transmission of imaging and video data needs routing protocols with both energy efficiency and Quality of Service (QoS) characteristics in order to guarantee the efficient use of the sensor nodes and effective access to the collected data. Also, with integration of real time applications in Wireless Senor Networks (WSNs), the use of QoS routing protocols is not only becoming a significant topic, but is also gaining the attention of researchers. In designing an efficient QoS routing protocol, the reliability and guarantee of end-to-end delay are critical events while conserving energy. Thus, considerable research has been focused on designing energy efficient and robust QoS routing protocols. In this paper, we present a state of the art research work based on real-time QoS routing protocols for WMSNs that have already been proposed. This paper categorizes the real-time QoS routing protocols into probabilistic and deterministic protocols. In addition, both categories are classified into soft and hard real time protocols by highlighting the QoS issues including the limitations and features of each protocol. Furthermore, we have compared the performance of mobility-aware query based real-time QoS routing protocols from each category using Network Simulator-2 (NS2). This paper also focuses on the design challenges and future research directions as well as highlights the characteristics of each QoS routing protocol.

Real-Time QoS Routing Protocols in Wireless Multimedia Sensor Networks: Study and Analysis

PubMed Central

Alanazi, Adwan; Elleithy, Khaled

2015-01-01

Many routing protocols have been proposed for wireless sensor networks. These routing protocols are almost always based on energy efficiency. However, recent advances in complementary metal-oxide semiconductor (CMOS) cameras and small microphones have led to the development of Wireless Multimedia Sensor Networks (WMSN) as a class of wireless sensor networks which pose additional challenges. The transmission of imaging and video data needs routing protocols with both energy efficiency and Quality of Service (QoS) characteristics in order to guarantee the efficient use of the sensor nodes and effective access to the collected data. Also, with integration of real time applications in Wireless Senor Networks (WSNs), the use of QoS routing protocols is not only becoming a significant topic, but is also gaining the attention of researchers. In designing an efficient QoS routing protocol, the reliability and guarantee of end-to-end delay are critical events while conserving energy. Thus, considerable research has been focused on designing energy efficient and robust QoS routing protocols. In this paper, we present a state of the art research work based on real-time QoS routing protocols for WMSNs that have already been proposed. This paper categorizes the real-time QoS routing protocols into probabilistic and deterministic protocols. In addition, both categories are classified into soft and hard real time protocols by highlighting the QoS issues including the limitations and features of each protocol. Furthermore, we have compared the performance of mobility-aware query based real-time QoS routing protocols from each category using Network Simulator-2 (NS2). This paper also focuses on the design challenges and future research directions as well as highlights the characteristics of each QoS routing protocol. PMID:26364639

Single-source chest-abdomen-pelvis cancer staging on a third generation dual-source CT system: comparison of automated tube potential selection to second generation dual-source CT.

PubMed

Park, Clara; Gruber-Rouh, Tatjana; Leithner, Doris; Zierden, Amelie; Albrecht, Mortiz H; Wichmann, Julian L; Bodelle, Boris; Elsabaie, Mohamed; Scholtz, Jan-Erik; Kaup, Moritz; Vogl, Thomas J; Beeres, Martin

2016-10-10

Evaluation of latest generation automated attenuation-based tube potential selection (ATPS) impact on image quality and radiation dose in contrast-enhanced chest-abdomen-pelvis computed tomography examinations for gynaecologic cancer staging. This IRB approved single-centre, observer-blinded retrospective study with a waiver for informed consent included a total of 100 patients with contrast-enhanced chest-abdomen-pelvis CT for gynaecologic cancer staging. All patients were examined with activated ATPS for adaption of tube voltage to body habitus. 50 patients were scanned on a third-generation dual-source CT (DSCT), and another 50 patients on a second-generation DSCT. Predefined image quality setting remained stable between both groups at 120 kV and a current of 210 Reference mAs. Subjective image quality assessment was performed by two blinded readers independently. Attenuation and image noise were measured in several anatomic structures. Signal-to-noise ratio (SNR) was calculated. For the evaluation of radiation exposure, CT dose index (CTDI vol ) values were compared. Diagnostic image quality was obtained in all patients. The median CTDI vol (6.1 mGy, range 3.9-22 mGy) was 40 % lower when using the algorithm compared with the previous ATCM protocol (median 10.2 mGy · cm, range 5.8-22.8 mGy). A reduction in potential to 90 kV occurred in 19 cases, a reduction to 100 kV in 23 patients and a reduction to 110 kV in 3 patients of our experimental cohort. These patients received significantly lower radiation exposure compared to the former used protocol. Latest generation automated ATPS on third-generation DSCT provides good diagnostic image quality in chest-abdomen-pelvis CT while average radiation dose is reduced by 40 % compared to former ATPS protocol on second-generation DSCT.

Abbreviated MRI Protocols for Detecting Breast Cancer in Women with Dense Breasts.

PubMed

Chen, Shuang-Qing; Huang, Min; Shen, Yu-Ying; Liu, Chen-Lu; Xu, Chuan-Xiao

2017-01-01

To evaluate the validity of two abbreviated protocols (AP) of MRI in breast cancer screening of dense breast tissue. This was a retrospective study in 356 participants with dense breast tissue and negative mammography results. The study was approved by the Nanjing Medical University Ethics Committee. Patients were imaged with a full diagnostic protocol (FDP) of MRI. Two APs (AP-1 consisting of the first post-contrast subtracted [FAST] and maximum-intensity projection [MIP] images, and AP-2 consisting of AP-1 combined with diffusion-weighted imaging [DWI]) and FDP images were analyzed separately, and the sensitivities and specificities of breast cancer detection were calculated. Of the 356 women, 67 lesions were detected in 67 women (18.8%) by standard MR protocol, and histological examination revealed 14 malignant lesions and 53 benign lesions. The average interpretation time of AP-1 and AP-2 were 37 seconds and 54 seconds, respectively, while the average interpretation time of the FDP was 3 minutes and 25 seconds. The sensitivities of the AP-1, AP-2, and FDP were 92.9, 100, and 100%, respectively, and the specificities of the three MR protocols were 86.5, 95.0, and 96.8%, respectively. There was no significant difference among the three MR protocols in the diagnosis of breast cancer ( p > 0.05). However, the specificity of AP-1 was significantly lower than that of AP-2 ( p = 0.031) and FDP ( p = 0.035), while there was no difference between AP-2 and FDP ( p > 0.05). The AP may be efficient in the breast cancer screening of dense breast tissue. FAST and MIP images combined with DWI of MRI are helpful to improve the specificity of breast cancer detection.

The role of advanced reconstruction algorithms in cardiac CT

PubMed Central

Halliburton, Sandra S.; Tanabe, Yuki; Partovi, Sasan

2017-01-01

Non-linear iterative reconstruction (IR) algorithms have been increasingly incorporated into clinical cardiac CT protocols at institutions around the world. Multiple IR algorithms are available commercially from various vendors. IR algorithms decrease image noise and are primarily used to enable lower radiation dose protocols. IR can also be used to improve image quality for imaging of obese patients, coronary atherosclerotic plaques, coronary stents, and myocardial perfusion. In this article, we will review the various applications of IR algorithms in cardiac imaging and evaluate how they have changed practice. PMID:29255694

Three-pass protocol scheme for bitmap image security by using vernam cipher algorithm

NASA Astrophysics Data System (ADS)

Rachmawati, D.; Budiman, M. A.; Aulya, L.

2018-02-01

Confidentiality, integrity, and efficiency are the crucial aspects of data security. Among the other digital data, image data is too prone to abuse of operation like duplication, modification, etc. There are some data security techniques, one of them is cryptography. The security of Vernam Cipher cryptography algorithm is very dependent on the key exchange process. If the key is leaked, security of this algorithm will collapse. Therefore, a method that minimizes key leakage during the exchange of messages is required. The method which is used, is known as Three-Pass Protocol. This protocol enables message delivery process without the key exchange. Therefore, the sending messages process can reach the receiver safely without fear of key leakage. The system is built by using Java programming language. The materials which are used for system testing are image in size 200×200 pixel, 300×300 pixel, 500×500 pixel, 800×800 pixel and 1000×1000 pixel. The result of experiments showed that Vernam Cipher algorithm in Three-Pass Protocol scheme could restore the original image.

Current Status of Efforts on Standardizing Magnetic Resonance Imaging of Juvenile Idiopathic Arthritis: Report from the OMERACT MRI in JIA Working Group and Health-e-Child.

PubMed

Nusman, Charlotte M; Ording Muller, Lil-Sofie; Hemke, Robert; Doria, Andrea S; Avenarius, Derk; Tzaribachev, Nikolay; Malattia, Clara; van Rossum, Marion A J; Maas, Mario; Rosendahl, Karen

2016-01-01

To report on the progress of an ongoing research collaboration on magnetic resonance imaging (MRI) in juvenile idiopathic arthritis (JIA) and describe the proceedings of a meeting, held prior to Outcome Measures in Rheumatology (OMERACT) 12, bringing together the OMERACT MRI in JIA working group and the Health-e-Child radiology group. The goal of the meeting was to establish agreement on scoring definitions, locations, and scales for the assessment of MRI of patients with JIA for both large and small joints. The collaborative work process included premeeting surveys, presentations, group discussions, consensus on scoring methods, pilot scoring, conjoint review, and discussion of a future research agenda. The meeting resulted in preliminary statements on the MR imaging protocol of the JIA knee and wrist and determination of the starting point for development of MRI scoring systems based on previous studies. It was also considered important to be descriptive rather than explanatory in the assessment of MRI in JIA (e.g., "thickening" instead of "hypertrophy"). Further, the group agreed that well-designed calibration sessions were warranted before any future scoring exercises were conducted. The combined efforts of the OMERACT MRI in JIA working group and Health-e-Child included the assessment of currently available material in the literature and determination of the basis from which to start the development of MRI scoring systems for both the knee and wrist. The future research agenda for the knee and wrist will include establishment of MRI scoring systems, an atlas of MR imaging in healthy children, and MRI protocol requisites.

Optimization of image quality in pulmonary CT angiography with low dose of contrast material

NASA Astrophysics Data System (ADS)

Assi, Abed Al Nasser; Abu Arra, Ali

2017-06-01

Aim: The aim of this study was to compare objective image quality data for patient pulmonary embolism between a conventional pulmonary CTA protocol with respect to a novel acquisition protocol performed with optimize radiation dose and less amount of iodinated contrast medium injected to the patients during PE scanning. Materials and Methods: Sixty- four patients with Pulmonary Embolism (PE) possibility, were examined using angio-CT protocol. Patients were randomly assigned to two groups: A (16 women and 16 men, with age ranging from 19-89 years) mean age, 62 years with standard deviation 16; range, 19-89 years) - injected contrast agent: 35-40 ml. B (16 women and 16 men, with age ranging from 28-86 years) - injected contrast agent: 70-80 ml. Other scanning parameters were kept constant. Pulmonary vessel enhancement and image noise were quantified; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective vessel contrast was assessed by two radiologists in consensus. Result: A total of 14 cases of PE (22 %) were found in the evaluated of subjects (nine in group A, and five in group B). All PE cases were detected by the two readers. There was no significant difference in the size or location of the PEs between the two groups, the average image noise was 14 HU for group A and 19 HU for group B. The difference was not statistically significant (p = 0.09). Overall, the SNR and CNR were slightly higher on group B (24.4 and 22.5 respectively) compared with group A (19.4 and 16.4 respectively), but those differences were not statistically significant (p = 0.71 and p = 0.35, respectively). Conclusion and Discussion: Both groups that had been evaluated by pulmonary CTA protocol allow similar image quality to be achieved as compared with each other's, with optimize care dose for both protocol and contrast volume were reduced by 50 % in new protocol comparing to the conventional protocol.

Setup deviations for whole-breast radiotherapy with TomoDirect: A comparison of weekly and biweekly image-guided protocols

NASA Astrophysics Data System (ADS)

Jung, Jae Hong; Jung, Joo-Young; Bae, Sun Hyun; Moon, Seong Kwon; Cho, Kwang Hwan

2016-10-01

The purpose of this study was to compare patient setup deviations for different image-guided protocols (weekly vs. biweekly) that are used in TomoDirect three-dimensional conformal radiotherapy (TD-3DCRT) for whole-breast radiation therapy (WBRT). A total of 138 defined megavoltage computed tomography (MVCT) image sets from 46 breast cancer cases were divided into two groups based on the imaging acquisition times: weekly or biweekly. The mean error, three-dimensional setup displacement error (3D-error), systematic error (Σ), and random error (σ) were calculated for each group. The 3D-errors were 4.29 ± 1.11 mm and 5.02 ± 1.85 mm for the weekly and biweekly groups, respectively; the biweekly error was 14.6% higher than the weekly error. The systematic errors in the roll angle and the x, y, and z directions were 0.48°, 1.72 mm, 2.18 mm, and 1.85 mm for the weekly protocol and 0.21°, 1.24 mm, 1.39 mm, and 1.85 mm for the biweekly protocol. Random errors in the roll angle and the x, y, and z directions were 25.7%, 40.6%, 40.0%, and 40.8% higher in the biweekly group than in the weekly group. For the x, y, and z directions, the distributions of the treatment frequency at less than 5 mm were 98.6%, 91.3%, and 94.2% in the weekly group and 94.2%, 89.9%, and 82.6% in the biweekly group. Moreover, the roll angles with 0 - 1° were 79.7% and 89.9% in the weekly and the biweekly groups, respectively. Overall, the evaluation of setup deviations for the two protocols revealed no significant differences (p > 0.05). Reducing the frequency of MVCT imaging could have promising effects on imaging doses and machine times during treatment. However, the biweekly protocol was associated with increased random setup deviations in the treatment. We have demonstrated a biweekly protocol of TD-3DCRT for WBRT, and we anticipate that our method may provide an alternative approach for considering the uncertainties in the patient setup.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lakshminarayan, Raghuram, E-mail: raghuram.lakshminarayan@hey.nhs.u; Simpson, James O.; Ettles, Duncan F., E-mail: Duncan.Ettles@hey.nhs.u

Magnetic resonance angiography (MRA) has become an established imaging modality in the management of lower-limb arterial disease, with emerging roles in treatment planning and follow-up. Contrast-enhanced MRA is now the most widely used technique with clinically acceptable results in the majority of patients. Difficulties in imaging and image interpretation are recognised in certain subgroups, including patients with critical limb ischaemia as well as patients with stents. Although newer contrast agents and refined imaging protocols may offer some solutions to these problems, this optimism is balanced by concerns about the toxicity of certain gadolinium chelates. Further development of interventional MRA remainsmore » one of the most significant challenges in the development of magnetic resonance imaging-guided peripheral vascular intervention. The status of MRA in managing patients with lower-limb arterial disease in current clinical practice is reviewed.« less

Multi-pass transmission electron microscopy

DOE PAGES

Juffmann, Thomas; Koppell, Stewart A.; Klopfer, Brannon B.; ...

2017-05-10

Feynman once asked physicists to build better electron microscopes to be able to watch biology at work. While electron microscopes can now provide atomic resolution, electron beam induced specimen damage precludes high resolution imaging of sensitive materials, such as single proteins or polymers. Here, we use simulations to show that an electron microscope based on a multi-pass measurement protocol enables imaging of single proteins, without averaging structures over multiple images. While we demonstrate the method for particular imaging targets, the approach is broadly applicable and is expected to improve resolution and sensitivity for a range of electron microscopy imaging modalities,more » including, for example, scanning and spectroscopic techniques. The approach implements a quantum mechanically optimal strategy which under idealized conditions can be considered interaction-free.« less

Ultra-low dose quantitative CT myocardial perfusion imaging with sparse-view dynamic acquisition and image reconstruction: A feasibility study.

PubMed

Enjilela, Esmaeil; Lee, Ting-Yim; Hsieh, Jiang; Wisenberg, Gerald; Teefy, Patrick; Yadegari, Andrew; Bagur, Rodrigo; Islam, Ali; Branch, Kelley; So, Aaron

2018-03-01

We implemented and validated a compressed sensing (CS) based algorithm for reconstructing dynamic contrast-enhanced (DCE) CT images of the heart from sparsely sampled X-ray projections. DCE CT imaging of the heart was performed on five normal and ischemic pigs after contrast injection. DCE images were reconstructed with filtered backprojection (FBP) and CS from all projections (984-view) and 1/3 of all projections (328-view), and with CS from 1/4 of all projections (246-view). Myocardial perfusion (MP) measurements with each protocol were compared to those with the reference 984-view FBP protocol. Both the 984-view CS and 328-view CS protocols were in good agreements with the reference protocol. The Pearson correlation coefficients of 984-view CS and 328-view CS determined from linear regression analyses were 0.98 and 0.99 respectively. The corresponding mean biases of MP measurement determined from Bland-Altman analyses were 2.7 and 1.2ml/min/100g. When only 328 projections were used for image reconstruction, CS was more accurate than FBP for MP measurement with respect to 984-view FBP. However, CS failed to generate MP maps comparable to those with 984-view FBP when only 246 projections were used for image reconstruction. DCE heart images reconstructed from one-third of a full projection set with CS were minimally affected by aliasing artifacts, leading to accurate MP measurements with the effective dose reduced to just 33% of conventional full-view FBP method. The proposed CS sparse-view image reconstruction method could facilitate the implementation of sparse-view dynamic acquisition for ultra-low dose CT MP imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

Image-fusion of MR spectroscopic images for treatment planning of gliomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang Jenghwa; Thakur, Sunitha; Perera, Gerard

2006-01-15

{sup 1}H magnetic resonance spectroscopic imaging (MRSI) can improve the accuracy of target delineation for gliomas, but it lacks the anatomic resolution needed for image fusion. This paper presents a simple protocol for fusing simulation computer tomography (CT) and MRSI images for glioma intensity-modulated radiotherapy (IMRT), including a retrospective study of 12 patients. Each patient first underwent whole-brain axial fluid-attenuated-inversion-recovery (FLAIR) MRI (3 mm slice thickness, no spacing), followed by three-dimensional (3D) MRSI measurements (TE/TR: 144/1000 ms) of a user-specified volume encompassing the extent of the tumor. The nominal voxel size of MRSI ranged from 8x8x10 mm{sup 3} to 12x12x10more » mm{sup 3}. A system was developed to grade the tumor using the choline-to-creatine (Cho/Cr) ratios from each MRSI voxel. The merged MRSI images were then generated by replacing the Cho/Cr value of each MRSI voxel with intensities according to the Cho/Cr grades, and resampling the poorer-resolution Cho/Cr map into the higher-resolution FLAIR image space. The FUNCTOOL processing software was also used to create the screen-dumped MRSI images in which these data were overlaid with each FLAIR MRI image. The screen-dumped MRSI images were manually translated and fused with the FLAIR MRI images. Since the merged MRSI images were intrinsically fused with the FLAIR MRI images, they were also registered with the screen-dumped MRSI images. The position of the MRSI volume on the merged MRSI images was compared with that of the screen-dumped MRSI images and was shifted until agreement was within a predetermined tolerance. Three clinical target volumes (CTVs) were then contoured on the FLAIR MRI images corresponding to the Cho/Cr grades. Finally, the FLAIR MRI images were fused with the simulation CT images using a mutual-information algorithm, yielding an IMRT plan that simultaneously delivers three different dose levels to the three CTVs. The image-fusion protocol was tested on 12 (six high-grade and six low-grade) glioma patients. The average agreement of the MRSI volume position on the screen-dumped MRSI images and the merged MRSI images was 0.29 mm with a standard deviation of 0.07 mm. Of all the voxels with Cho/Cr grade one or above, the distribution of Cho/Cr grade was found to correlate with the glioma grade from pathologic finding and is consistent with literature results indicating Cho/Cr elevation as a marker for malignancy. In conclusion, an image-fusion protocol was developed that successfully incorporates MRSI information into the IMRT treatment plan for glioma.« less

Homogenization of sample absorption for the imaging of large and dense fossils with synchrotron microtomography.

PubMed

Sanchez, Sophie; Fernandez, Vincent; Pierce, Stephanie E; Tafforeau, Paul

2013-09-01

Propagation phase-contrast synchrotron radiation microtomography (PPC-SRμCT) has proved to be very successful for examining fossils. Because fossils range widely in taphonomic preservation, size, shape and density, X-ray computed tomography protocols are constantly being developed and refined. Here we present a 1-h procedure that combines a filtered high-energy polychromatic beam with long-distance PPC-SRμCT (sample to detector: 4-16 m) and an attenuation protocol normalizing the absorption profile (tested on 13-cm-thick and 5.242 g cm(-3) locally dense samples but applicable to 20-cm-thick samples). This approach provides high-quality imaging results, which show marked improvement relative to results from images obtained without the attenuation protocol in apparent transmission, contrast and signal-to-noise ratio. The attenuation protocol involves immersing samples in a tube filled with aluminum or glass balls in association with a U-shaped aluminum profiler. This technique therefore provides access to a larger dynamic range of the detector used for tomographic reconstruction. This protocol homogenizes beam-hardening artifacts, thereby rendering it effective for use with conventional μCT scanners.

Application of two segmentation protocols during the processing of virtual images in rapid prototyping: ex vivo study with human dry mandibles.

PubMed

Ferraz, Eduardo Gomes; Andrade, Lucio Costa Safira; dos Santos, Aline Rode; Torregrossa, Vinicius Rabelo; Rubira-Bullen, Izabel Regina Fischer; Sarmento, Viviane Almeida

2013-12-01

The aim of this study was to evaluate the accuracy of virtual three-dimensional (3D) reconstructions of human dry mandibles, produced from two segmentation protocols ("outline only" and "all-boundary lines"). Twenty virtual three-dimensional (3D) images were built from computed tomography exam (CT) of 10 dry mandibles, in which linear measurements between anatomical landmarks were obtained and compared to an error probability of 5 %. The results showed no statistically significant difference among the dry mandibles and the virtual 3D reconstructions produced from segmentation protocols tested (p = 0,24). During the designing of a virtual 3D reconstruction, both "outline only" and "all-boundary lines" segmentation protocols can be used. Virtual processing of CT images is the most complex stage during the manufacture of the biomodel. Establishing a better protocol during this phase allows the construction of a biomodel with characteristics that are closer to the original anatomical structures. This is essential to ensure a correct preoperative planning and a suitable treatment.

Overall evaluability of low dose protocol for computed tomography angiography of thoracic aorta using 80 kV and iterative reconstruction algorithm using different concentration contrast media.

PubMed

Annoni, Andrea Daniele; Mancini, Maria E; Andreini, Daniele; Formenti, Alberto; Mushtaq, Saima; Nobili, Enrica; Guglielmo, Marco; Baggiano, Andrea; Conte, Edoardo; Pepi, Mauro

2017-10-01

Multidetector Computed Tomography Angiography (MDCTA) is presently the imaging modality of choice for aortic disease. However, the effective radiation dose and the risk related to the use of contrast agents associated with MDCTA is an issue of concern. Aim of this study was to assess image quality of a low dose ECG-gated MDCTA of thoracic aorta using different concentration contrast media without tailored injection protocol. Two-hundred patients were randomised into four different scan protocols: Group A (Iodixanol 320 and 80 Kvp tube voltage), Group B (Iodixanol 320 and 100 Kvp tube voltage), Group C (Iomeprol 400 and 80 Kvp tube voltage) and Group D (Iomeprol 400 and 100 Kvp tube voltage). Image quality, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and effective dose (ED) were compared among groups. No significant differences in image noise, SNR and CNR between groups with the same tube voltage. Significant differences in SNR and CNR were found among groups with 80 kV versus groups using 100 kV but without differences in terms of image quality. ED was significantly lower in groups with 80 kV. Multidetector Computed Tomography Angiography protocols using 80 kV and low concentration contrast media are feasible without need of tailored injection protocols. © 2017 The Royal Australian and New Zealand College of Radiologists.

Providing Internet Access to High-Resolution Lunar Images

NASA Technical Reports Server (NTRS)

Plesea, Lucian

2008-01-01

The OnMoon server is a computer program that provides Internet access to high-resolution Lunar images, maps, and elevation data, all suitable for use in geographical information system (GIS) software for generating images, maps, and computational models of the Moon. The OnMoon server implements the Open Geospatial Consortium (OGC) Web Map Service (WMS) server protocol and supports Moon-specific extensions. Unlike other Internet map servers that provide Lunar data using an Earth coordinate system, the OnMoon server supports encoding of data in Moon-specific coordinate systems. The OnMoon server offers access to most of the available high-resolution Lunar image and elevation data. This server can generate image and map files in the tagged image file format (TIFF) or the Joint Photographic Experts Group (JPEG), 8- or 16-bit Portable Network Graphics (PNG), or Keyhole Markup Language (KML) format. Image control is provided by use of the OGC Style Layer Descriptor (SLD) protocol. Full-precision spectral arithmetic processing is also available, by use of a custom SLD extension. This server can dynamically add shaded relief based on the Lunar elevation to any image layer. This server also implements tiled WMS protocol and super-overlay KML for high-performance client application programs.

In situ Compressive Loading and Correlative Noninvasive Imaging of the Bone-periodontal Ligament-tooth Fibrous Joint

PubMed Central

Jang, Andrew T.; Lin, Jeremy D.; Seo, Youngho; Etchin, Sergey; Merkle, Arno; Fahey, Kevin; Ho, Sunita P.

2014-01-01

This study demonstrates a novel biomechanics testing protocol. The advantage of this protocol includes the use of an in situ loading device coupled to a high resolution X-ray microscope, thus enabling visualization of internal structural elements under simulated physiological loads and wet conditions. Experimental specimens will include intact bone-periodontal ligament (PDL)-tooth fibrous joints. Results will illustrate three important features of the protocol as they can be applied to organ level biomechanics: 1) reactionary force vs. displacement: tooth displacement within the alveolar socket and its reactionary response to loading, 2) three-dimensional (3D) spatial configuration and morphometrics: geometric relationship of the tooth with the alveolar socket, and 3) changes in readouts 1 and 2 due to a change in loading axis, i.e. from concentric to eccentric loads. Efficacy of the proposed protocol will be evaluated by coupling mechanical testing readouts to 3D morphometrics and overall biomechanics of the joint. In addition, this technique will emphasize on the need to equilibrate experimental conditions, specifically reactionary loads prior to acquiring tomograms of fibrous joints. It should be noted that the proposed protocol is limited to testing specimens under ex vivo conditions, and that use of contrast agents to visualize soft tissue mechanical response could lead to erroneous conclusions about tissue and organ-level biomechanics. PMID:24638035

Diffusion Tensor Imaging and Resting-State Functional MRI-Scanning in 5- and 6-Year-Old Children: Training Protocol and Motion Assessment

PubMed Central

Theys, Catherine; Wouters, Jan; Ghesquière, Pol

2014-01-01

Advanced Magnetic Resonance Imaging (MRI) techniques such as Diffusion Tensor Imaging (DTI) and resting-state functional MRI (rfMRI) are widely used to study structural and functional neural connectivity. However, as these techniques are highly sensitive to motion artifacts and require a considerable amount of time for image acquisition, successful acquisition of these images can be challenging to complete with certain populations. This is especially true for young children. This paper describes a new approach termed the ‘submarine protocol’, designed to prepare 5- and 6-year-old children for advanced MRI scanning. The submarine protocol aims to ensure that successful scans can be acquired in a time- and resource-efficient manner, without the need for sedation. This manuscript outlines the protocol and details its outcomes, as measured through the number of children who completed the scanning procedure and analysis of the degree of motion present in the acquired images. Seventy-six children aged between 5.8 and 6.9 years were trained using the submarine protocol and subsequently underwent DTI and rfMRI scanning. After completing the submarine protocol, 75 of the 76 children (99%) completed their DTI-scan and 72 children (95%) completed the full 35-minute scan session. Results of diffusion data, acquired in 75 children, showed that the motion in 60 of the scans (80%) did not exceed the threshold for excessive motion. In the rfMRI scans, this was the case for 62 of the 71 scans (87%). When placed in the context of previous studies, the motion data of the 5- and 6-year-old children reported here were as good as, or better than those previously reported for groups of older children (i.e., 8-year-olds). Overall, this study shows that the submarine protocol can be used successfully to acquire DTI and rfMRI scans in 5 and 6-year-old children, without the need for sedation or lengthy training procedures. PMID:24718364

Effectiveness of Interventions to Decrease Image Ordering for Low Back Pain Presentations in the Emergency Department: A Systematic Review.

PubMed

Liu, Chaocheng; Desai, Shashwat; Krebs, Lynette D; Kirkland, Scott W; Keto-Lambert, Diana; Rowe, Brian H

2018-01-08

Low back pain (LBP) is an extremely frequent reason for patients to present to an emergency department (ED). Despite evidence against the utility of imaging, simple and advanced imaging (i.e., computed tomography [CT], magnetic resonance imaging) for patients with LBP has become increasingly frequent in the ED. The objective of this review was to identify and examine the effectiveness of interventions aimed at reducing image ordering in the ED for LBP patients. A protocol was developed a priori, following the PRISMA guidelines, and registered with PROSPERO. Six bibliographic databases (including MEDLINE, EMBASE, EBM Reviews, SCOPUS, CINAHL, and Dissertation Abstracts) and the gray literature were searched. Comparative studies assessing interventions that targeted image ordering in the ED for adult patients with LBP were eligible for inclusion. Two reviewers independently screened study eligibility and completed data extraction. Study quality was completed independently by two reviewers using the before-after quality assessment checklist, with a third-party mediator resolving any differences. Due to a limited number of studies and significant heterogeneity, only a descriptive analysis was performed. The search yielded 603 unique citations of which a total of five before-after studies were included. Quality assessment identified potential biases relating to comparability between the pre- and postintervention groups, reliable assessment of outcomes, and an overall lack of information on the intervention (i.e., time point, description, intervention data collection). The type of interventions utilized included clinical decision support tools, clinical practice guidelines, a knowledge translation initiative, and multidisciplinary protocols. Overall, four studies reported a decrease in the relative percentage change in imaging in a specific image modality (22.7%-47.4%) following implementation of the interventions; however, one study reported a 35% increase in patient referrals to radiography, while another study reported a subsequent 15.4% increase in referrals to CT and myelography after implementing an intervention which reduced referrals for simple radiography. While imaging of LBP has been identified as a key area of imaging overuse (e.g., Choosing Wisely recommendation), evidence on interventions to reduce image ordering for ED patients with LBP is sparse. There is some evidence to suggest that interventions can reduce the use of simple imaging in LBP in the ED; however, a shift in imaging modality has also been demonstrated. Additional studies employing higher-quality methods and measuring intervention fidelity are strongly recommended to further explore the potential of ED-based interventions to reduce image ordering for this patient population. © 2018 by the Society for Academic Emergency Medicine.

Performance assessment of small-package-class nonintrusive inspection systems

NASA Astrophysics Data System (ADS)

Spradling, Michael L.; Hyatt, Roger

1997-02-01

The DoD Counterdrug Technology Development Program has addressed the development and demonstration of technology to enhance nonintrusive inspection of small packages such as passenger baggage, commercially delivered parcels, and breakbulk cargo items. Within the past year they have supported several small package-class nonintrusive inspection system performance assessment activities. All performance assessment programs involved the use of a red/blue team concept and were conducted in accordance with approved assessment protocols. This paper presents a discussion related to the systematic performance assessment of small package-class nonintrusive inspection technologies, including transmission, backscatter and computed tomography x-ray imaging, and protocol-related considerations for the assessment of these systems.

Near-infrared fluorescence image-guidance in plastic surgery: A systematic review.

PubMed

Cornelissen, Anouk J M; van Mulken, Tom J M; Graupner, Caitlin; Qiu, Shan S; Keuter, Xavier H A; van der Hulst, René R W J; Schols, Rutger M

2018-01-01

Near-infrared fluorescence (NIRF) imaging technique, after administration of contrast agents with fluorescent characteristics in the near-infrared (700-900 nm) range, is considered to possess great potential for the future of plastic surgery, given its capacity for perioperative, real-time anatomical guidance and identification. This study aimed to provide a comprehensive literature review concerning current and potential future applications of NIRF imaging in plastic surgery, thereby guiding future research. A systematic literature search was performed in databases of Cochrane Library CENTRAL, MEDLINE, and EMBASE (last search Oct 2017) regarding NIRF imaging in plastic surgery. Identified articles were screened and checked for eligibility by two authors independently. Forty-eight selected studies included 1166 animal/human subjects in total. NIRF imaging was described for a variety of (pre)clinical applications in plastic surgery. Thirty-two articles used NIRF angiography, i.e., vascular imaging after intravenous dye administration. Ten articles reported on NIRF lymphography after subcutaneous dye administration. Although currently most applied, general protocols for dosage and timing of dye administration for NIRF angiography and lymphography are still lacking. Three articles applied NIRF to detect nerve injury, and another three studies described other novel applications in plastic surgery. Future standard implementation of novel intraoperative optical techniques, such as NIRF imaging, could significantly contribute to perioperative anatomy guidance and facilitate critical decision-making in plastic surgical procedures. Further investigation (i.e., large multicenter randomized controlled trials) is mandatory to establish the true value of this innovative surgical imaging technique in standard clinical practice and to aid in forming consensus on protocols for general use.Level of Evidence: Not ratable.

Guidelines on nuclear medicine imaging in neuroblastoma.

PubMed

Bar-Sever, Zvi; Biassoni, Lorenzo; Shulkin, Barry; Kong, Grace; Hofman, Michael S; Lopci, Egesta; Manea, Irina; Koziorowski, Jacek; Castellani, Rita; Boubaker, Ariane; Lambert, Bieke; Pfluger, Thomas; Nadel, Helen; Sharp, Susan; Giammarile, Francesco

2018-06-25

Nuclear medicine has a central role in the diagnosis, staging, response assessment and long-term follow-up of neuroblastoma, the most common solid extracranial tumour in children. These EANM guidelines include updated information on 123 I-mIBG, the most common study in nuclear medicine for the evaluation of neuroblastoma, and on PET/CT imaging with 18 F-FDG, 18 F-DOPA and 68 Ga-DOTA peptides. These PET/CT studies are increasingly employed in clinical practice. Indications, advantages and limitations are presented along with recommendations on study protocols, interpretation of findings and reporting results.

Hair product artifact in magnetic resonance imaging.

PubMed

Chenji, Sneha; Wilman, Alan H; Mah, Dennell; Seres, Peter; Genge, Angela; Kalra, Sanjay

2017-01-01

The presence of metallic compounds in facial cosmetics and permanent tattoos may affect the quality of magnetic resonance imaging. We report a case study describing a signal artifact due to the use of a leave-on powdered hair dye. On reviewing the ingredients of the product, it was found to contain several metallic compounds. In lieu of this observation, we suggest that MRI centers include the use of metal- or mineral-based facial cosmetics or hair products in their screening protocols. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of Optical Artifacts in a Laser-Based Spacecraft Navigation Sensor

NASA Technical Reports Server (NTRS)

LeCroy, Jerry E.; Howard, Richard T.; Hallmark, Dean S.

2007-01-01

Testing of the Advanced Video Guidance Sensor (AVGS) used for proximity operations navigation on the Orbital Express ASTRO spacecraft exposed several unanticipated imaging system artifacts and aberrations that required correction to meet critical navigation performance requirements. Mitigation actions are described for a number of system error sources, including lens aberration, optical train misalignment, laser speckle, target image defects, and detector nonlinearity/noise characteristics. Sensor test requirements and protocols are described, along with a summary of test results from sensor confidence tests and system performance testing.

Effects of Optical Artifacts in a Laser-Based Spacecraft Navigation Sensor

NASA Technical Reports Server (NTRS)

LeCroy, Jerry E.; Hallmark, Dean S.; Howard, Richard T.

2007-01-01

Testing Of the Advanced Video Guidance Sensor (AVGS) used for proximity operations navigation on the Orbital Express ASTRO spacecraft exposed several unanticipated imaging system artifacts and aberrations that required correction, to meet critical navigation performance requirements. Mitigation actions are described for a number of system error sources, including lens aberration, optical train misalignment, laser speckle, target image defects, and detector nonlinearity/noise characteristics. Sensor test requirements and protocols are described, along with a summary ,of test results from sensor confidence tests and system performance testing.

SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Y; Bowsher, J; Yan, S

2014-06-01

Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with {sup 18}F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medicalmore » Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better accuracy.« less

Implementation and assessment of an animal management system for small-animal micro-CT / micro-SPECT imaging

NASA Astrophysics Data System (ADS)

Holdsworth, David W.; Detombe, Sarah A.; Chiodo, Chris; Fricke, Stanley T.; Drangova, Maria

2011-03-01

Advances in laboratory imaging systems for CT, SPECT, MRI, and PET facilitate routine micro-imaging during pre-clinical investigations. Challenges still arise when dealing with immune-compromised animals, biohazardous agents, and multi-modality imaging. These challenges can be overcome with an appropriate animal management system (AMS), with the capability for supporting and monitoring a rat or mouse during micro-imaging. We report the implementation and assessment of a new AMS system for mice (PRA-3000 / AHS-2750, ASI Instruments, Warren MI), designed to be compatible with a commercial micro-CT / micro-SPECT imaging system (eXplore speCZT, GE Healthcare, London ON). The AMS was assessed under the following criteria: 1) compatibility with the imaging system (i.e. artifact generation, geometric dimensions); 2) compatibility with live animals (i.e. positioning, temperature regulation, anesthetic supply); 3) monitoring capabilities (i.e. rectal temperature, respiratory and cardiac monitoring); 4) stability of co-registration; and 5) containment. Micro-CT scans performed using a standardized live-animal protocol (90 kVp, 40 mA, 900 views, 16 ms per view) exhibited low noise (+/-19 HU) and acceptable artifact from high-density components within the AMS (e.g. ECG pad contacts). Live mice were imaged repeatedly (with removal and replacement of the AMS) and spatial registration was found to be stable to within +/-0.07 mm. All animals tolerated enclosure within the AMS for extended periods (i.e. > one hour) without distress, based on continuous recordings of rectal temperature, ECG waveform and respiratory rate. A sealed AMS system extends the capability of a conventional micro-imaging system to include immune-compromised and biosafety level 2 mouse-imaging protocols.

Security Issues for Mobile Medical Imaging: A Primer.

PubMed

Choudhri, Asim F; Chatterjee, Arindam R; Javan, Ramin; Radvany, Martin G; Shih, George

2015-10-01

The end-user of mobile device apps in the practice of clinical radiology should be aware of security measures that prevent unauthorized use of the device, including passcode policies, methods for dealing with failed login attempts, network manager-controllable passcode enforcement, and passcode enforcement for the protection of the mobile device itself. Protection of patient data must be in place that complies with the Health Insurance Portability and Accountability Act and U.S. Federal Information Processing Standards. Device security measures for data protection include methods for locally stored data encryption, hardware encryption, and the ability to locally and remotely clear data from the device. As these devices transfer information over both local wireless networks and public cell phone networks, wireless network security protocols, including wired equivalent privacy and Wi-Fi protected access, are important components in the chain of security. Specific virtual private network protocols, Secure Sockets Layer and related protocols (especially in the setting of hypertext transfer protocols), native apps, virtual desktops, and nonmedical commercial off-the-shelf apps require consideration in the transmission of medical data over both private and public networks. Enterprise security and management of both personal and enterprise mobile devices are discussed. Finally, specific standards for hardware and software platform security, including prevention of hardware tampering, protection from malicious software, and application authentication methods, are vital components in establishing a secure platform for the use of mobile devices in the medical field. © RSNA, 2015.

Integration of Optical Coherence Tomography Scan Patterns to Augment Clinical Data Suite

NASA Technical Reports Server (NTRS)

Mason, S.; Patel, N.; Van Baalen, M.; Tarver, W.; Otto, C.; Samuels, B.; Koslovsky, M.; Schaefer, C.; Taiym, W.; Wear, M.;

Spectral domain optical coherence tomography imaging of retinal diseases in Singapore.

PubMed

Singh, Mandeep; Chee, Caroline K L

2009-01-01

In this retrospective case series, the authors reviewed cases of patients with macular disorders whose eyes had been imaged using spectral domain optical coherence tomography (SD-OCT) (Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA). SD-OCT images were obtained from patients with a variety of ocular conditions attending a tertiary retinal clinic in Singapore from August 2007 to December 2007, according to standardized protocols. Images of 428 eyes from 301 patients were reviewed. Ocular diagnoses included diabetic macular edema, exudative age-related macular degeneration, central serous chorioretinopathy, cystoid macular edema, retinal vein and artery occlusions, infective chorioretinitis, and others. The authors present four cases of particular interest to illustrate how SD-OCT was useful in complementing the clinician's assessment of macular disease.

TestDose: A nuclear medicine software based on Monte Carlo modeling for generating gamma camera acquisitions and dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia, Marie-Paule, E-mail: marie-paule.garcia@univ-brest.fr; Villoing, Daphnée; McKay, Erin

Purpose: The TestDose platform was developed to generate scintigraphic imaging protocols and associated dosimetry by Monte Carlo modeling. TestDose is part of a broader project (www.dositest.com) whose aim is to identify the biases induced by different clinical dosimetry protocols. Methods: The TestDose software allows handling the whole pipeline from virtual patient generation to resulting planar and SPECT images and dosimetry calculations. The originality of their approach relies on the implementation of functional segmentation for the anthropomorphic model representing a virtual patient. Two anthropomorphic models are currently available: 4D XCAT and ICRP 110. A pharmacokinetic model describes the biodistribution of amore » given radiopharmaceutical in each defined compartment at various time-points. The Monte Carlo simulation toolkit GATE offers the possibility to accurately simulate scintigraphic images and absorbed doses in volumes of interest. The TestDose platform relies on GATE to reproduce precisely any imaging protocol and to provide reference dosimetry. For image generation, TestDose stores user’s imaging requirements and generates automatically command files used as input for GATE. Each compartment is simulated only once and the resulting output is weighted using pharmacokinetic data. Resulting compartment projections are aggregated to obtain the final image. For dosimetry computation, emission data are stored in the platform database and relevant GATE input files are generated for the virtual patient model and associated pharmacokinetics. Results: Two samples of software runs are given to demonstrate the potential of TestDose. A clinical imaging protocol for the Octreoscan™ therapeutical treatment was implemented using the 4D XCAT model. Whole-body “step and shoot” acquisitions at different times postinjection and one SPECT acquisition were generated within reasonable computation times. Based on the same Octreoscan™ kinetics, a dosimetry computation performed on the ICRP 110 model is also presented. Conclusions: The proposed platform offers a generic framework to implement any scintigraphic imaging protocols and voxel/organ-based dosimetry computation. Thanks to the modular nature of TestDose, other imaging modalities could be supported in the future such as positron emission tomography.« less

TestDose: A nuclear medicine software based on Monte Carlo modeling for generating gamma camera acquisitions and dosimetry.

PubMed

Garcia, Marie-Paule; Villoing, Daphnée; McKay, Erin; Ferrer, Ludovic; Cremonesi, Marta; Botta, Francesca; Ferrari, Mahila; Bardiès, Manuel

2015-12-01

The TestDose platform was developed to generate scintigraphic imaging protocols and associated dosimetry by Monte Carlo modeling. TestDose is part of a broader project (www.dositest.com) whose aim is to identify the biases induced by different clinical dosimetry protocols. The TestDose software allows handling the whole pipeline from virtual patient generation to resulting planar and SPECT images and dosimetry calculations. The originality of their approach relies on the implementation of functional segmentation for the anthropomorphic model representing a virtual patient. Two anthropomorphic models are currently available: 4D XCAT and ICRP 110. A pharmacokinetic model describes the biodistribution of a given radiopharmaceutical in each defined compartment at various time-points. The Monte Carlo simulation toolkit gate offers the possibility to accurately simulate scintigraphic images and absorbed doses in volumes of interest. The TestDose platform relies on gate to reproduce precisely any imaging protocol and to provide reference dosimetry. For image generation, TestDose stores user's imaging requirements and generates automatically command files used as input for gate. Each compartment is simulated only once and the resulting output is weighted using pharmacokinetic data. Resulting compartment projections are aggregated to obtain the final image. For dosimetry computation, emission data are stored in the platform database and relevant gate input files are generated for the virtual patient model and associated pharmacokinetics. Two samples of software runs are given to demonstrate the potential of TestDose. A clinical imaging protocol for the Octreoscan™ therapeutical treatment was implemented using the 4D XCAT model. Whole-body "step and shoot" acquisitions at different times postinjection and one SPECT acquisition were generated within reasonable computation times. Based on the same Octreoscan™ kinetics, a dosimetry computation performed on the ICRP 110 model is also presented. The proposed platform offers a generic framework to implement any scintigraphic imaging protocols and voxel/organ-based dosimetry computation. Thanks to the modular nature of TestDose, other imaging modalities could be supported in the future such as positron emission tomography.

Image quality comparison between single energy and dual energy CT protocols for hepatic imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Yuan, E-mail: yuanyao@stanford.edu; Pelc, Nor

Purpose: Multi-detector computed tomography (MDCT) enables volumetric scans in a single breath hold and is clinically useful for hepatic imaging. For simple tasks, conventional single energy (SE) computed tomography (CT) images acquired at the optimal tube potential are known to have better quality than dual energy (DE) blended images. However, liver imaging is complex and often requires imaging of both structures containing iodinated contrast media, where atomic number differences are the primary contrast mechanism, and other structures, where density differences are the primary contrast mechanism. Hence it is conceivable that the broad spectrum used in a dual energy acquisition maymore » be an advantage. In this work we are interested in comparing these two imaging strategies at equal-dose and more complex settings. Methods: We developed numerical anthropomorphic phantoms to mimic realistic clinical CT scans for medium size and large size patients. MDCT images based on the defined phantoms were simulated using various SE and DE protocols at pre- and post-contrast stages. For SE CT, images from 60 kVp through 140 with 10 kVp steps were considered; for DE CT, both 80/140 and 100/140 kVp scans were simulated and linearly blended at the optimal weights. To make a fair comparison, the mAs of each scan was adjusted to match the reference radiation dose (120 kVp, 200 mAs for medium size patients and 140 kVp, 400 mAs for large size patients). Contrast-to-noise ratio (CNR) of liver against other soft tissues was used to evaluate and compare the SE and DE protocols, and multiple pre- and post-contrasted liver-tissue pairs were used to define a composite CNR. To help validate the simulation results, we conducted a small clinical study. Eighty-five 120 kVp images and 81 blended 80/140 kVp images were collected and compared through both quantitative image quality analysis and an observer study. Results: In the simulation study, we found that the CNR of pre-contrast SE image mostly increased with increasing kVp while for post-contrast imaging 90 kVp or lower yielded higher CNR images, depending on the differential iodine concentration of each tissue. Similar trends were seen in DE blended CNR and those from SE protocols. In the presence of differential iodine concentration (i.e., post-contrast), the CNR curves maximize at lower kVps (80–120), with the peak shifted rightward for larger patients. The combined pre- and post-contrast composite CNR study demonstrated that an optimal SE protocol has better performance than blended DE images, and the optimal tube potential for SE scan is around 90 kVp for a medium size patients and between 90 and 120 kVp for large size patients (although low kVp imaging requires high x-ray tube power to avoid photon starvation). Also, a tin filter added to the high kVp beam is not only beneficial for material decomposition but it improves the CNR of the DE blended images as well. The dose adjusted CNR of the clinical images also showed the same trend and radiologists favored the SE scans over blended DE images. Conclusions: Our simulation showed that an optimized SE protocol produces up to 5% higher CNR for a range of clinical tasks. The clinical study also suggested 120 kVp SE scans have better image quality than blended DE images. Hence, blended DE images do not have a fundamental CNR advantage over optimized SE images.« less

Micro-computed tomography imaging and analysis in developmental biology and toxicology.

PubMed

Wise, L David; Winkelmann, Christopher T; Dogdas, Belma; Bagchi, Ansuman

2013-06-01

Micro-computed tomography (micro-CT) is a high resolution imaging technique that has expanded and strengthened in use since it was last reviewed in this journal in 2004. The technology has expanded to include more detailed analysis of bone, as well as soft tissues, by use of various contrast agents. It is increasingly applied to questions in developmental biology and developmental toxicology. Relatively high-throughput protocols now provide a powerful and efficient means to evaluate embryos and fetuses subjected to genetic manipulations or chemical exposures. This review provides an overview of the technology, including scanning, reconstruction, visualization, segmentation, and analysis of micro-CT generated images. This is followed by a review of more recent applications of the technology in some common laboratory species that highlight the diverse issues that can be addressed. Copyright © 2013 Wiley Periodicals, Inc.

Combining fluorescence imaging with Hi-C to study 3D genome architecture of the same single cell.

PubMed

Lando, David; Basu, Srinjan; Stevens, Tim J; Riddell, Andy; Wohlfahrt, Kai J; Cao, Yang; Boucher, Wayne; Leeb, Martin; Atkinson, Liam P; Lee, Steven F; Hendrich, Brian; Klenerman, Dave; Laue, Ernest D

2018-05-01

Fluorescence imaging and chromosome conformation capture assays such as Hi-C are key tools for studying genome organization. However, traditionally, they have been carried out independently, making integration of the two types of data difficult to perform. By trapping individual cell nuclei inside a well of a 384-well glass-bottom plate with an agarose pad, we have established a protocol that allows both fluorescence imaging and Hi-C processing to be carried out on the same single cell. The protocol identifies 30,000-100,000 chromosome contacts per single haploid genome in parallel with fluorescence images. Contacts can be used to calculate intact genome structures to better than 100-kb resolution, which can then be directly compared with the images. Preparation of 20 single-cell Hi-C libraries using this protocol takes 5 d of bench work by researchers experienced in molecular biology techniques. Image acquisition and analysis require basic understanding of fluorescence microscopy, and some bioinformatics knowledge is required to run the sequence-processing tools described here.

Magnetic resonance imaging of the inner ear by using a hybrid radiofrequency coil at 7 T

NASA Astrophysics Data System (ADS)

Kim, Kyoung-Nam; Heo, Phil; Kim, Young-Bo; Han, Gyu-Cheol

2015-01-01

Visualization of the membranous structures of the inner ear has been limited to the detection of the normal fluid signal intensity within the bony labyrinth by using magnetic resonance imaging (MRI) equipped with a 1.5 Tesla (T) magnet. High-field (HF) MRI has been available for more than a decade, and numerous studies have documented its significant advantages over conventional MRI with regards to its use in basic scientific research and routine clinical assessments. No previous studies of the inner ear by using HF MRI have been reported, in part because high-quality resolution of mastoid pneumatization is challenging due to artifacts generated in the HF environment and insufficient performance of radiofrequency (RF) coils. Therefore, a hybrid RF coil with integrated circuitry was developed at 7 T and was targeted for anatomical imaging to achieve a high resolution image of the structure of the human inner ear, excluding the bony portion. The inner-ear's structure is composed of soft tissues containing hydrogen ions and includes the membranous labyrinth, endolymphatic space, perilymphatic space, and cochlear-vestibular nerves. Visualization of the inner-ear's anatomy was performed in-vivo with a custom-designed hybrid RF coil and a specific imaging protocol based on an interpolated breath-held examination sequence. The comparative signal intensity value at 30-mm away from the phantom side was 88% higher for the hybrid RF coil and 24% higher for the 8-channel transmit/receive (Tx/Rx) coil than for the commercial birdcage coil. The optimized MRI protocol employed a hybrid RF coil because it enabled high-resolution imaging of the inner-ear's anatomy and accurate mapping of structures including the cochlea and the semicircular canals. These results indicate that 7 T MRI achieves high spatial resolution visualization of the inner-ear's anatomy. Therefore, MRI imaging using a hybrid RF coil at 7 T could provide a powerful tool for clinical investigations of petrous pathologies of the inner ear.

Multi-institutional MicroCT image comparison of image-guided small animal irradiators

NASA Astrophysics Data System (ADS)

Johnstone, Chris D.; Lindsay, Patricia; E Graves, Edward; Wong, Eugene; Perez, Jessica R.; Poirier, Yannick; Ben-Bouchta, Youssef; Kanesalingam, Thilakshan; Chen, Haijian; E Rubinstein, Ashley; Sheng, Ke; Bazalova-Carter, Magdalena

2017-07-01

To recommend imaging protocols and establish tolerance levels for microCT image quality assurance (QA) performed on conformal image-guided small animal irradiators. A fully automated QA software SAPA (small animal phantom analyzer) for image analysis of the commercial Shelley micro-CT MCTP 610 phantom was developed, in which quantitative analyses of CT number linearity, signal-to-noise ratio (SNR), uniformity and noise, geometric accuracy, spatial resolution by means of modulation transfer function (MTF), and CT contrast were performed. Phantom microCT scans from eleven institutions acquired with four image-guided small animal irradiator units (including the commercial PXi X-RAD SmART and Xstrahl SARRP systems) with varying parameters used for routine small animal imaging were analyzed. Multi-institutional data sets were compared using SAPA, based on which tolerance levels for each QA test were established and imaging protocols for QA were recommended. By analyzing microCT data from 11 institutions, we established image QA tolerance levels for all image quality tests. CT number linearity set to R 2  >  0.990 was acceptable in microCT data acquired at all but three institutions. Acceptable SNR  >  36 and noise levels  <55 HU were obtained at five of the eleven institutions, where failing scans were acquired with current-exposure time of less than 120 mAs. Acceptable spatial resolution (>1.5 lp mm-1 for MTF  =  0.2) was obtained at all but four institutions due to their large image voxel size used (>0.275 mm). Ten of the eleven institutions passed the set QA tolerance for geometric accuracy (<1.5%) and nine of the eleven institutions passed the QA tolerance for contrast (>2000 HU for 30 mgI ml-1). We recommend performing imaging QA with 70 kVp, 1.5 mA, 120 s imaging time, 0.20 mm voxel size, and a frame rate of 5 fps for the PXi X-RAD SmART. For the Xstrahl SARRP, we recommend using 60 kVp, 1.0 mA, 240 s imaging time, 0.20 mm voxel size, and 6 fps. These imaging protocols should result in high quality images that pass the set tolerance levels on all systems. Average SAPA computation time for complete QA analysis for a 0.20 mm voxel, 400 slice Shelley phantom microCT data set was less than 20 s. We present image quality assurance recommendations for image-guided small animal radiotherapy systems that can aid researchers in maintaining high image quality, allowing for spatially precise conformal dose delivery to small animals.

Impact of voxel size variation on CBCT-based diagnostic outcome in dentistry: a systematic review.

PubMed

Spin-Neto, Rubens; Gotfredsen, Erik; Wenzel, Ann

2013-08-01

The objective of this study was to make a systematic review on the impact of voxel size in cone beam computed tomography (CBCT)-based image acquisition, retrieving evidence regarding the diagnostic outcome of those images. The MEDLINE bibliographic database was searched from 1950 to June 2012 for reports comparing diverse CBCT voxel sizes. The search strategy was limited to English-language publications using the following combined terms in the search strategy: (voxel or FOV or field of view or resolution) and (CBCT or cone beam CT). The results from the review identified 20 publications that qualitatively or quantitatively assessed the influence of voxel size on CBCT-based diagnostic outcome, and in which the methodology/results comprised at least one of the expected parameters (image acquisition, reconstruction protocols, type of diagnostic task, and presence of a gold standard). The diagnostic task assessed in the studies was diverse, including the detection of root fractures, the detection of caries lesions, and accuracy of 3D surface reconstruction and of bony measurements, among others. From the studies assessed, it is clear that no general protocol can be yet defined for CBCT examination of specific diagnostic tasks in dentistry. Rationale in this direction is an important step to define the utility of CBCT imaging.

Digital information management: a progress report on the National Digital Mammography Archive

NASA Astrophysics Data System (ADS)

Beckerman, Barbara G.; Schnall, Mitchell D.

2002-05-01

Digital mammography creates very large images, which require new approaches to storage, retrieval, management, and security. The National Digital Mammography Archive (NDMA) project, funded by the National Library of Medicine (NLM), is developing a limited testbed that demonstrates the feasibility of a national breast imaging archive, with access to prior exams; patient information; computer aids for image processing, teaching, and testing tools; and security components to ensure confidentiality of patient information. There will be significant benefits to patients and clinicians in terms of accessible data with which to make a diagnosis and to researchers performing studies on breast cancer. Mammography was chosen for the project, because standards were already available for digital images, report formats, and structures. New standards have been created for communications protocols between devices, front- end portal and archive. NDMA is a distributed computing concept that provides for sharing and access across corporate entities. Privacy, auditing, and patient consent are all integrated into the system. Five sites, Universities of Pennsylvania, Chicago, North Carolina and Toronto, and BWXT Y12, are connected through high-speed networks to demonstrate functionality. We will review progress, including technical challenges, innovative research and development activities, standards and protocols being implemented, and potential benefits to healthcare systems.

Recommendations on nuclear and multimodality imaging in IE and CIED infections.

PubMed

Erba, Paola Anna; Lancellotti, Patrizio; Vilacosta, Isidre; Gaemperli, Oliver; Rouzet, Francois; Hacker, Marcus; Signore, Alberto; Slart, Riemer H J A; Habib, Gilbert

2018-05-24

In the latest update of the European Society of Cardiology (ESC) guidelines for the management of infective endocarditis (IE), imaging is positioned at the centre of the diagnostic work-up so that an early and accurate diagnosis can be reached. Besides echocardiography, contrast-enhanced CT (ce-CT), radiolabelled leucocyte (white blood cell, WBC) SPECT/CT and [ 18 F]FDG PET/CT are included as diagnostic tools in the diagnostic flow chart for IE. Following the clinical guidelines that provided a straightforward message on the role of multimodality imaging, we believe that it is highly relevant to produce specific recommendations on nuclear multimodality imaging in IE and cardiac implantable electronic device infections. In these procedural recommendations we therefore describe in detail the technical and practical aspects of WBC SPECT/CT and [ 18 F]FDG PET/CT, including ce-CT acquisition protocols. We also discuss the advantages and limitations of each procedure, specific pitfalls when interpreting images, and the most important results from the literature, and also provide recommendations on the appropriate use of multimodality imaging.

A RESTful image gateway for multiple medical image repositories.

PubMed

Valente, Frederico; Viana-Ferreira, Carlos; Costa, Carlos; Oliveira, José Luis

2012-05-01

Mobile technologies are increasingly important components in telemedicine systems and are becoming powerful decision support tools. Universal access to data may already be achieved by resorting to the latest generation of tablet devices and smartphones. However, the protocols employed for communicating with image repositories are not suited to exchange data with mobile devices. In this paper, we present an extensible approach to solving the problem of querying and delivering data in a format that is suitable for the bandwidth and graphic capacities of mobile devices. We describe a three-tiered component-based gateway that acts as an intermediary between medical applications and a number of Picture Archiving and Communication Systems (PACS). The interface with the gateway is accomplished using Hypertext Transfer Protocol (HTTP) requests following a Representational State Transfer (REST) methodology, which relieves developers from dealing with complex medical imaging protocols and allows the processing of data on the server side.

Region-of-interest breast images with the Twente Photoacoustic Mammoscope (PAM)

NASA Astrophysics Data System (ADS)

Manohar, Srirang; Vaartjes, Sanne E.; van Hespen, Johan G. C.; Klaase, Joost M.; van den Engh, Frank M.; The, Andy K. H.; Steenbergen, Wiendelt; van Leeuwen, Ton G.

2007-02-01

The Twente Photoacoustic Mammoscope (PAM) is based on generating laser-induced ultrasound from absorbing structures in the breast. The heart of the instrument is a flat PVDF based detector matrix comprising 590 active elements. The exciting source is an Nd:YAG laser operating at 1064 nm with 5 ns pulses. The instrument is built around a hospital bed. A study protocol was designed to explore the feasibility of using the photoacoustic technique as embodied in PAM to detect cancer in the breasts of patients with suspect/symptomatic breasts. The protocol was approved by a Medical Ethics testing committee and the instrument approved for laser and electrical safety. The protocol was executed at the Medisch Spectrum Twente by using the mammoscope to obtain photoacoustic region-of-interest (ROI) images of the suspect/symptomatic breasts. We report on one case and compare the photoacoustic images obtained with x-ray mammograms and ultrasound images.

Three-dimensional image technology in forensic anthropology: Assessing the validity of biological profiles derived from CT-3D images of the skeleton

NASA Astrophysics Data System (ADS)

Garcia de Leon Valenzuela, Maria Julia

This project explores the reliability of building a biological profile for an unknown individual based on three-dimensional (3D) images of the individual's skeleton. 3D imaging technology has been widely researched for medical and engineering applications, and it is increasingly being used as a tool for anthropological inquiry. While the question of whether a biological profile can be derived from 3D images of a skeleton with the same accuracy as achieved when using dry bones has been explored, bigger sample sizes, a standardized scanning protocol and more interobserver error data are needed before 3D methods can become widely and confidently used in forensic anthropology. 3D images of Computed Tomography (CT) scans were obtained from 130 innominate bones from Boston University's skeletal collection (School of Medicine). For each bone, both 3D images and original bones were assessed using the Phenice and Suchey-Brooks methods. Statistical analysis was used to determine the agreement between 3D image assessment versus traditional assessment. A pool of six individuals with varying experience in the field of forensic anthropology scored a subsample (n = 20) to explore interobserver error. While a high agreement was found for age and sex estimation for specimens scored by the author, the interobserver study shows that observers found it difficult to apply standard methods to 3D images. Higher levels of experience did not result in higher agreement between observers, as would be expected. Thus, a need for training in 3D visualization before applying anthropological methods to 3D bones is suggested. Future research should explore interobserver error using a larger sample size in order to test the hypothesis that training in 3D visualization will result in a higher agreement between scores. The need for the development of a standard scanning protocol focusing on the optimization of 3D image resolution is highlighted. Applications for this research include the possibility of digitizing skeletal collections in order to expand their use and for deriving skeletal collections from living populations and creating population-specific standards. Further research for the development of a standard scanning and processing protocol is needed before 3D methods in forensic anthropology are considered as reliable tools for generating biological profiles.

Nuclear myocardial perfusion imaging using thallium-201 with a novel multifocal collimator SPECT/CT: IQ-SPECT versus conventional protocols in normal subjects.

PubMed

Matsuo, Shinro; Nakajima, Kenichi; Onoguchi, Masahisa; Wakabayash, Hiroshi; Okuda, Koichi; Kinuya, Seigo

2015-06-01

A novel multifocal collimator, IQ-SPECT (Siemens) consists of SMARTZOOM, cardio-centric and 3D iterative SPECT reconstruction and makes it possible to perform MPI scans in a short time. The aims are to delineate the normal uptake in thallium-201 ((201)Tl) SPECT in each acquisition method and to compare the distribution between new and conventional protocol, especially in patients with normal imaging. Forty patients (eight women, mean age of 75 years) who underwent myocardial perfusion imaging were included in the study. All patients underwent one-day protocol perfusion scan after an adenosine-stress test and at rest after administering (201)Tl and showed normal results. Acquisition was performed on a Symbia T6 equipped with a conventional dual-headed gamma camera system (Siemens ECAM) and with a multifocal SMARTZOOM collimator. Imaging was performed with a conventional system followed by IQ-SPECT/computed tomography (CT). Reconstruction was performed with or without X-ray CT-derived attenuation correction (AC). Two nuclear physicians blinded to clinical information interpreted all myocardial perfusion images. A semi-quantitative myocardial perfusion was analyzed by a 17-segment model with a 5-point visual scoring. The uptake of each segment was measured and left ventricular functions were analyzed by QPS software. IQ-SPECT provided good or excellent image quality. The quality of IQ-SPECT images without AC was similar to those of conventional LEHR study. Mid-inferior defect score (0.3 ± 0.5) in the conventional LEHR study was increased significantly in IQ-SPECT with AC (0 ± 0). IQ-SPECT with AC improved the mid-inferior decreased perfusion shown in conventional images. The apical tracer count in IQ-SPECT with AC was decreased compared to that in LEHR (0.1 ± 0.3 vs. 0.5 ± 0.7, p < 0.05). The left ventricular ejection fraction from IQ-SPECT was significantly higher than that from the LEHR collimator (p = 0.0009). The images of IQ-SPECT acquired in a short time are equivalent to that of conventional LEHR. The results indicated that the IQ-SPECT system with AC is capable of correcting inferior artifacts with high image quality.

SU-F-R-06: Traumatic Brachial Plexus Injury Imaging, Developing a Coherent Clinical Protocol From Literature Review Through Practice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, D; France, E; Lambert, J

Purpose: Medical Physics teams can now play a critical role to help plan and provide studied approaches for traumatic brachial plexus MR imaging (tbpMRI). This is especially important for coordination with uncommon applications, since it is challenging to select the right modality, parameters, and train technologists on the essential components. For this work, we started with a review of the medical literature, performed crossover/volunteer studies to bring tbpMRI to practice with greater image QC and protocol management. Methods: To the best of our knowledge, we reviewed the known searchable domain for tbpMRI. We found 69 total articles since 2000. Articlesmore » were evaluated with our published protocol for literature management (LIMES3). Two physicists and two radiologists condensed the information from all articles into a knowledgebase. Results: The initial literature demonstrated great heterogeneity, which was a sign that this area needed greater consistency. Despite inconsistency and imprecision, we extracted the most relevant targets using our long-term experience with protocol development in MSK. We ran volunteers on six different magnets of various field strengths with multiple receiver coils, and rebuilt a coherent protocol for tbpMRI. Our radiologists rated LIMES3 work as superior. We have received referrals from the ER and have conducted four patient evaluations. Conclusion: Traumatic brachial plexus MRI has great possible benefits for patients. This work supports the complexity of tbpMRI scanning. As this is rarely performed, it requires a more diligent protocol workflow, coordination of caregivers, and education within multiple clinical departments. Choosing the correct imaging exam can be critical, as patients can have significant neuropathy and/or paralysis. The LIMES3 protocol is well liked at our institution, and forms the cornerstone of understanding for our work. Our literature management led to a better clinical protocol creation despite the diffuse and inconclusive information presented in the existing medical literature.« less

MRI vs. CT for orthodontic applications: comparison of two MRI protocols and three CT (multislice, cone-beam, industrial) technologies.

PubMed

Detterbeck, Andreas; Hofmeister, Michael; Hofmann, Elisabeth; Haddad, Daniel; Weber, Daniel; Hölzing, Astrid; Zabler, Simon; Schmid, Matthias; Hiller, Karl-Heinz; Jakob, Peter; Engel, Jens; Hiller, Jochen; Hirschfelder, Ursula

2016-07-01

To examine the relative usefulness and suitability of magnetic resonance imaging (MRI) in daily clinical practice as compared to various technologies of computed tomography (CT) in addressing questions of orthodontic interest. Three blinded raters evaluated 2D slices and 3D reconstructions created from scans of two pig heads. Five imaging modalities were used, including three CT technologies-multislice (MSCT), cone-beam CT (CBCT), and industrial (µCT)-and two MRI protocols with different scan durations. Defined orthodontic parameters were rated one by one on the 2D slices and the 3D reconstructions, followed by final overall ratings for each modality. A mixed linear model was used for statistical analysis. Based on the 2D slices, the parameter of visualizing tooth-germ topography did not yield any significantly different ratings for MRI versus any of the CT scans. While some ratings for the other parameters did involve significant differences, how these should be interpreted depends greatly on the relevance of each parameter. Based on the 3D reconstructions, the only significant difference between technologies was noted for the parameter of visualizing root-surface morphology. Based on the final overall ratings, the imaging performance of the standard MRI protocol was noninferior to the performance of the three CT technologies. On comparing the imaging performance of MRI and CT scans, it becomes clear that MRI has a huge potential for applications in daily clinical practice. Given its additional benefits of a good contrast ratio and complete absence of ionizing radiation, further studies are needed to explore this clinical potential in greater detail.

Evaluation of an iterative model-based CT reconstruction algorithm by intra-patient comparison of standard and ultra-low-dose examinations.

PubMed

Noël, Peter B; Engels, Stephan; Köhler, Thomas; Muenzel, Daniela; Franz, Daniela; Rasper, Michael; Rummeny, Ernst J; Dobritz, Martin; Fingerle, Alexander A

2018-01-01

Background The explosive growth of computer tomography (CT) has led to a growing public health concern about patient and population radiation dose. A recently introduced technique for dose reduction, which can be combined with tube-current modulation, over-beam reduction, and organ-specific dose reduction, is iterative reconstruction (IR). Purpose To evaluate the quality, at different radiation dose levels, of three reconstruction algorithms for diagnostics of patients with proven liver metastases under tumor follow-up. Material and Methods A total of 40 thorax-abdomen-pelvis CT examinations acquired from 20 patients in a tumor follow-up were included. All patients were imaged using the standard-dose and a specific low-dose CT protocol. Reconstructed slices were generated by using three different reconstruction algorithms: a classical filtered back projection (FBP); a first-generation iterative noise-reduction algorithm (iDose4); and a next generation model-based IR algorithm (IMR). Results The overall detection of liver lesions tended to be higher with the IMR algorithm than with FBP or iDose4. The IMR dataset at standard dose yielded the highest overall detectability, while the low-dose FBP dataset showed the lowest detectability. For the low-dose protocols, a significantly improved detectability of the liver lesion can be reported compared to FBP or iDose 4 ( P = 0.01). The radiation dose decreased by an approximate factor of 5 between the standard-dose and the low-dose protocol. Conclusion The latest generation of IR algorithms significantly improved the diagnostic image quality and provided virtually noise-free images for ultra-low-dose CT imaging.

Low-Dose CT of the Paranasal Sinuses: Minimizing X-Ray Exposure with Spectral Shaping.

PubMed

Wuest, Wolfgang; May, Matthias; Saake, Marc; Brand, Michael; Uder, Michael; Lell, Michael

2016-11-01

Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort. In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192x0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 × 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures. All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDI vol 1.2 mGy vs. 4.4 mGy, p < 0.001). Spectral optimization (tin filtration at 100 kV) allows for visualization of the paranasal sinus with sufficient image quality at a very low radiation exposure. • Spectral optimization (tin filtration) is beneficial to low-dose parasinus CT • Tin filtration at 100 kV yields sufficient image quality for pre-operative planning • Diagnostic parasinus CT can be performed with an effective dose <0.05 mSv.

SU-E-I-82: Improving CT Image Quality for Radiation Therapy Using Iterative Reconstruction Algorithms and Slightly Increasing Imaging Doses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noid, G; Chen, G; Tai, A

2014-06-01

Purpose: Iterative reconstruction (IR) algorithms are developed to improve CT image quality (IQ) by reducing noise without diminishing spatial resolution or contrast. For CT in radiation therapy (RT), slightly increasing imaging dose to improve IQ may be justified if it can substantially enhance structure delineation. The purpose of this study is to investigate and to quantify the IQ enhancement as a result of increasing imaging doses and using IR algorithms. Methods: CT images were acquired for phantoms, built to evaluate IQ metrics including spatial resolution, contrast and noise, with a variety of imaging protocols using a CT scanner (Definition ASmore » Open, Siemens) installed inside a Linac room. Representative patients were scanned once the protocols were optimized. Both phantom and patient scans were reconstructed using the Sinogram Affirmed Iterative Reconstruction (SAFIRE) and the Filtered Back Projection (FBP) methods. IQ metrics of the obtained CTs were compared. Results: IR techniques are demonstrated to preserve spatial resolution as measured by the point spread function and reduce noise in comparison to traditional FBP. Driven by the reduction in noise, the contrast to noise ratio is doubled by adopting the highest SAFIRE strength. As expected, increasing imaging dose reduces noise for both SAFIRE and FBP reconstructions. The contrast to noise increases from 3 to 5 by increasing the dose by a factor of 4. Similar IQ improvement was observed on the CTs for selected patients with pancreas and prostrate cancers. Conclusion: The IR techniques produce a measurable enhancement to CT IQ by reducing the noise. Increasing imaging dose further reduces noise independent of the IR techniques. The improved CT enables more accurate delineation of tumors and/or organs at risk during RT planning and delivery guidance.« less

Transfer learning improves supervised image segmentation across imaging protocols.

PubMed

van Opbroek, Annegreet; Ikram, M Arfan; Vernooij, Meike W; de Bruijne, Marleen

2015-05-01

The variation between images obtained with different scanners or different imaging protocols presents a major challenge in automatic segmentation of biomedical images. This variation especially hampers the application of otherwise successful supervised-learning techniques which, in order to perform well, often require a large amount of labeled training data that is exactly representative of the target data. We therefore propose to use transfer learning for image segmentation. Transfer-learning techniques can cope with differences in distributions between training and target data, and therefore may improve performance over supervised learning for segmentation across scanners and scan protocols. We present four transfer classifiers that can train a classification scheme with only a small amount of representative training data, in addition to a larger amount of other training data with slightly different characteristics. The performance of the four transfer classifiers was compared to that of standard supervised classification on two magnetic resonance imaging brain-segmentation tasks with multi-site data: white matter, gray matter, and cerebrospinal fluid segmentation; and white-matter-/MS-lesion segmentation. The experiments showed that when there is only a small amount of representative training data available, transfer learning can greatly outperform common supervised-learning approaches, minimizing classification errors by up to 60%.

A no-key-exchange secure image sharing scheme based on Shamir's three-pass cryptography protocol and the multiple-parameter fractional Fourier transform.

PubMed

Lang, Jun

2012-01-30

In this paper, we propose a novel secure image sharing scheme based on Shamir's three-pass protocol and the multiple-parameter fractional Fourier transform (MPFRFT), which can safely exchange information with no advance distribution of either secret keys or public keys between users. The image is encrypted directly by the MPFRFT spectrum without the use of phase keys, and information can be shared by transmitting the encrypted image (or message) three times between users. Numerical simulation results are given to verify the performance of the proposed algorithm.

CT angiography of the aorta using 80 kVp in combination with sinogram-affirmed iterative reconstruction and automated tube current modulation: Effects on image quality and radiation dose.

PubMed

Boos, Johannes; Aissa, Joel; Lanzman, Rotem S; Heusch, Philipp; Schimmöller, Lars; Schleich, Christoph; Thomas, Christoph; Antoch, Gerald; Kröpil, Patric

2016-04-01

The objective of this study was to evaluate image quality and radiation dose of a CT angiography (CTA) protocol using 80 kVp in combination with iterative reconstruction and automated tube current modulation. Ninety-five aortic CTA examinations were included in this study. A novel 80 kVp aortic CTA-protocol with iterative reconstruction was introduced in our department in March 2012 for patients with a body mass index (BMI) below 32 kg/m(2). The first 72 consecutive examinations were retrospectively assigned to group A (56 patients, 42 men, 14 women, mean age 69.6 ± 10.7 years, BMI range 19.7-31.1 kg/m(2)). For comparison, the last 23 consecutive examinations performed with the old protocol (100 kVp) were assigned to group B (21 patients, 13 men, 8 women, mean age 67.4 ± 11.1 years, BMI range 19.7-31.9 kg/m(2)). Thoracic and abdominal contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and aortic attenuation were assessed. Subjective image quality was rated on a 5-point scale (1 = non diagnostic; 5 = excellent). Furthermore, dose length product (DLP) and volumetric computed tomography dose index (CTDIvol) were analysed. All examinations achieved diagnostic image quality. Attenuation of the aorta was significantly higher in group A compared with B (thoracic: 443.5 ± 90.5 Hounsfield units (HU) vs. 296.0 ± 61.0 HU; abdominal: 426.3 ± 94.2 HU vs. 283.6 ± 60.5 HU; P < 0.05, respectively). CNR, SNR and subjective image quality were comparable between both groups (CNR: 12.8 ± 3.7 vs. 13.0 ± 7.4; SNR 14.4 ± 3.9 vs. 14.9 ± 8.2; subjective image quality: 4.3 ± 0.6 vs. 4.5 ± 0.6; P > 0.05, respectively). CTDIvol and DLP were significantly lower in group A (1.9 ± 0.5 mGy; 139.2 ± 41.1 mGy × cm) as compared with group B (4.2 ± 1.4 mGy; 292.1 ± 91.5 mGy × cm; P < 0.001, respectively). Low-dose CTA of the aorta using 80 kVp with iterative reconstruction enables a significant dose reduction of up to 50% compared with a 100 kVp protocol in patients with a BMI below 32 kg/m(2) while diagnostic image quality is maintained. © 2016 The Royal Australian and New Zealand College of Radiologists.

The effect of personalized versus standard patient protocols for radiostereometric analysis (RSA).

PubMed

Muharemovic, O; Troelsen, A; Thomsen, M G; Kallemose, T; Gosvig, K K

2018-05-01

Increasing pressure in the clinic requires a more standardized approach to radiostereometric analysis (RSA) imaging. The aim of this study was to investigate whether implementation of personalized RSA patient protocols could increase image quality and decrease examination time and the number of exposure repetitions. Forty patients undergoing primary total hip arthroplasty were equally randomized to either a case or a control group. Radiographers in the case group were assisted by personalized patient protocols containing information about each patient's post-operative RSA imaging. Radiographers in the control group used a standard RSA protocol. At three months, radiographers in the case group significantly reduced (p < 0.001) the number of exposures by 1.6, examination time with 19.2 min, and distance between centrum of prosthesis and centrum of calibration field with 34.1 mm when compared to post-operative (baseline) results. At twelve months, the case group significantly reduced (p < 0.001) number of exposures by two, examination time with 22.5 min, and centrum of prosthesis to centrum of calibration field distance with 43.1 mm when compared to baseline results. No significant improvements were found in the control group at any time point. There is strong evidence that personalized RSA patient protocols have a positive effect on image quality and radiation dose savings. Implementation of personal patient protocols as a RSA standard will contribute to the reduction of examination time, thus ensuring a cost benefit for department and patient safety. Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

The impact of routine surveillance screening with magnetic resonance imaging (MRI) to detect tumour recurrence in children with central nervous system (CNS) tumours: protocol for a systematic review and meta-analysis.

PubMed

Main, Caroline; Stevens, Simon P; Bailey, Simon; Phillips, Robert; Pizer, Barry; Wheatley, Keith; Kearns, Pamela R; English, Martin; Wilne, Sophie; Wilson, Jayne S

2016-08-31

The aim of this study is to assess the impact of routine MRI surveillance to detect tumour recurrence in children with no new neurological signs or symptoms compared with alternative follow-up practices, including periodic clinical and physical examinations and the use of non-routine imaging upon presentation with disease signs or symptoms. Standard systematic review methods aimed at minimising bias will be employed for study identification, selection and data extraction. Ten electronic databases have been searched, and further citation searching and reference checking will be employed. Randomised and non-randomised controlled trials assessing the impact of routine surveillance MRI to detect tumour recurrence in children with no new neurological signs or symptoms compared to alternative follow-up schedules including imaging upon presentation with disease signs or symptoms will be included. The primary outcome is time to change in therapeutic intervention. Secondary outcomes include overall survival, surrogate survival outcomes, response rates, diagnostic yield per set of images, adverse events, quality of survival and validated measures of family psychological functioning and anxiety. Two reviewers will independently screen and select studies for inclusion. Quality assessment will be undertaken using the Cochrane Collaboration's tools for assessing risk of bias. Where possible, data will be summarised using combined estimates of effect for time to treatment change, survival outcomes and response rates using assumption-free methods. Further sub-group analyses and meta-regression models will be specified and undertaken to explore potential sources of heterogeneity between studies within each tumour type if necessary. Assessment of the impact of surveillance imaging in children with CNS tumours is methodologically complex. The evidence base is likely to be heterogeneous in terms of imaging protocols, definitions of radiological response and diagnostic accuracy of tumour recurrence due to changes in imaging technology over time. Furthermore, the delineation of tumour recurrence from either pseudo-progression or radiation necrosis after radiotherapy is potentially problematic and linked to the timing of follow-up assessments. However, given the current routine practice of MRI surveillance in the follow-up of children with CNS tumours in the UK and the resource implications, it is important to evaluate the cost-benefit profile of this practice. PROSPERO CRD42016036802.

Influence of LCD color reproduction accuracy on observer performance using virtual pathology slides

NASA Astrophysics Data System (ADS)

Krupinski, Elizabeth A.; Silverstein, Louis D.; Hashmi, Syed F.; Graham, Anna R.; Weinstein, Ronald S.; Roehrig, Hans

2012-02-01

The use of color LCDs in medical imaging is growing as more clinical specialties use digital images as a resource in diagnosis and treatment decisions. Telemedicine applications such as telepathology, teledermatology and teleophthalmology rely heavily on color images. However, standard methods for calibrating, characterizing and profiling color displays do not exist, resulting in inconsistent presentation. To address this, we developed a calibration, characterization and profiling protocol for color-critical medical imaging applications. Physical characterization of displays calibrated with and without the protocol revealed high color reproduction accuracy with the protocol. The present study assessed the impact of this protocol on observer performance. A set of 250 breast biopsy virtual slide regions of interest (half malignant, half benign) were shown to 6 pathologists, once using the calibration protocol and once using the same display in its "native" off-the-shelf uncalibrated state. Diagnostic accuracy and time to render a decision were measured. In terms of ROC performance, Az (area under the curve) calibrated = 0.8640; uncalibrated = 0.8558. No statistically significant difference (p = 0.2719) was observed. In terms of interpretation speed, mean calibrated = 4.895 sec, mean uncalibrated = 6.304 sec which is statistically significant (p = 0.0460). Early results suggest a slight advantage diagnostically for a properly calibrated and color-managed display and a significant potential advantage in terms of improved workflow. Future work should be conducted using different types of color images that may be more dependent on accurate color rendering and a wider range of LCDs with varying characteristics.

The APOSTEL recommendations for reporting quantitative optical coherence tomography studies.

PubMed

Cruz-Herranz, Andrés; Balk, Lisanne J; Oberwahrenbrock, Timm; Saidha, Shiv; Martinez-Lapiscina, Elena H; Lagreze, Wolf A; Schuman, Joel S; Villoslada, Pablo; Calabresi, Peter; Balcer, Laura; Petzold, Axel; Green, Ari J; Paul, Friedemann; Brandt, Alexander U; Albrecht, Philipp

2016-06-14

To develop consensus recommendations for reporting of quantitative optical coherence tomography (OCT) study results. A panel of experienced OCT researchers (including 11 neurologists, 2 ophthalmologists, and 2 neuroscientists) discussed requirements for performing and reporting quantitative analyses of retinal morphology and developed a list of initial recommendations based on experience and previous studies. The list of recommendations was subsequently revised during several meetings of the coordinating group. We provide a 9-point checklist encompassing aspects deemed relevant when reporting quantitative OCT studies. The areas covered are study protocol, acquisition device, acquisition settings, scanning protocol, funduscopic imaging, postacquisition data selection, postacquisition data analysis, recommended nomenclature, and statistical analysis. The Advised Protocol for OCT Study Terminology and Elements recommendations include core items to standardize and improve quality of reporting in quantitative OCT studies. The recommendations will make reporting of quantitative OCT studies more consistent and in line with existing standards for reporting research in other biomedical areas. The recommendations originated from expert consensus and thus represent Class IV evidence. They will need to be regularly adjusted according to new insights and practices. © 2016 American Academy of Neurology.

Using machine learning for sequence-level automated MRI protocol selection in neuroradiology.

PubMed

Brown, Andrew D; Marotta, Thomas R

2018-05-01

Incorrect imaging protocol selection can lead to important clinical findings being missed, contributing to both wasted health care resources and patient harm. We present a machine learning method for analyzing the unstructured text of clinical indications and patient demographics from magnetic resonance imaging (MRI) orders to automatically protocol MRI procedures at the sequence level. We compared 3 machine learning models - support vector machine, gradient boosting machine, and random forest - to a baseline model that predicted the most common protocol for all observations in our test set. The gradient boosting machine model significantly outperformed the baseline and demonstrated the best performance of the 3 models in terms of accuracy (95%), precision (86%), recall (80%), and Hamming loss (0.0487). This demonstrates the feasibility of automating sequence selection by applying machine learning to MRI orders. Automated sequence selection has important safety, quality, and financial implications and may facilitate improvements in the quality and safety of medical imaging service delivery.

Technical Challenges of Enterprise Imaging: HIMSS-SIIM Collaborative White Paper.

PubMed

Clunie, David A; Dennison, Don K; Cram, Dawn; Persons, Kenneth R; Bronkalla, Mark D; Primo, Henri Rik

2016-10-01

This white paper explores the technical challenges and solutions for acquiring (capturing) and managing enterprise images, particularly those involving visible light applications. The types of acquisition devices used for various general-purpose photography and specialized applications including dermatology, endoscopy, and anatomic pathology are reviewed. The formats and standards used, and the associated metadata requirements and communication protocols for transfer and workflow are considered. Particular emphasis is placed on the importance of metadata capture in both order- and encounter-based workflow. The benefits of using DICOM to provide a standard means of recording and accessing both metadata and image and video data are considered, as is the role of IHE and FHIR.

TU-A-201-01: Introduction to In-Room Imaging System Characteristics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, J.

2016-06-15

Recent years have seen a widespread proliferation of available in-room image guidance systems for radiation therapy target localization with many centers having multiple in-room options. In this session, available imaging systems for in-room IGRT will be reviewed highlighting the main differences in workflow efficiency, targeting accuracy and image quality as it relates to target visualization. Decision-making strategies for integrating these tools into clinical image guidance protocols that are tailored to specific disease sites like H&N, lung, pelvis, and spine SBRT will be discussed. Learning Objectives: Major system characteristics of a wide range of available in-room imaging systems for IGRT. Advantagesmore » / disadvantages of different systems for site-specific IGRT considerations. Concepts of targeting accuracy and time efficiency in designing clinical imaging protocols.« less

TU-A-201-00: Image Guidance Technologies and Management Strategies

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2016-06-15

Recent years have seen a widespread proliferation of available in-room image guidance systems for radiation therapy target localization with many centers having multiple in-room options. In this session, available imaging systems for in-room IGRT will be reviewed highlighting the main differences in workflow efficiency, targeting accuracy and image quality as it relates to target visualization. Decision-making strategies for integrating these tools into clinical image guidance protocols that are tailored to specific disease sites like H&N, lung, pelvis, and spine SBRT will be discussed. Learning Objectives: Major system characteristics of a wide range of available in-room imaging systems for IGRT. Advantagesmore » / disadvantages of different systems for site-specific IGRT considerations. Concepts of targeting accuracy and time efficiency in designing clinical imaging protocols.« less

Principles of Management of Central Nervous System Infections.

PubMed

Singhi, Sunit; Angurana, Suresh Kumar

2018-01-15

CNS infections in children are medical emergency and are associated with high mortality and morbidity. For diagnosis, a high index of suspicion is required. Clinical assessment should be supplemented by laboratory investigations including CSF Gram stain and cultures, blood culture, PCR on CSF, serological tests, and imaging. Commonly associated life threatening complications include coma, seizure, raised intracranial pressure (ICP), focal deficits, shock, respiratory failure, and fluid and electrolyte abnormalities. Immediate management should first address control of airway, breathing and circulation; protocolized management of raised ICP and status epilepticus; maintaining adequate intravascular volume; and close monitoring for early detection of complications. Appropriate antimicrobial agents should be administered promptly according to the suspected pathogen. Clinical evaluation, laboratory workup, specific antimicrobial therapy, supportive treatment, and management of associated complications should go hand in hand in a protocolized way for better outcome.

Scanning protocols dedicated to smart velocity ranging in spectral OCT.

PubMed

Grulkowski, Ireneusz; Gorczynska, Iwona; Szkulmowski, Maciej; Szlag, Daniel; Szkulmowska, Anna; Leitgeb, Rainer A; Kowalczyk, Andrzej; Wojtkowski, Maciej

2009-12-21

We introduce a new type of scanning protocols, called segmented protocols, which enable extracting multi-range flow velocity information from a single Spectral OCT data set. The protocols are evaluated using a well defined flow in a glass capillary. As an example of in vivo studies, we demonstrate two- and three-dimensional imaging of the retinal vascular system in the eyes of healthy volunteers. The flow velocity detection is performed using a method of Joint Spectral and Time domain OCT. Velocity ranging is demonstrated in imaging of retinal vasculature in the macular region and in the optic disk area characterized by different flow velocity values. Additionally, an enhanced visualization of retinal capillary network is presented in the close proximity to macula.

Image quality of low-dose CCTA in obese patients: impact of high-definition computed tomography and adaptive statistical iterative reconstruction.

PubMed

Gebhard, Cathérine; Fuchs, Tobias A; Fiechter, Michael; Stehli, Julia; Stähli, Barbara E; Gaemperli, Oliver; Kaufmann, Philipp A

2013-10-01

The accuracy of coronary computed tomography angiography (CCTA) in obese persons is compromised by increased image noise. We investigated CCTA image quality acquired on a high-definition 64-slice CT scanner using modern adaptive statistical iterative reconstruction (ASIR). Seventy overweight and obese patients (24 males; mean age 57 years, mean body mass index 33 kg/m(2)) were studied with clinically-indicated contrast enhanced CCTA. Thirty-five patients underwent a standard definition protocol with filtered backprojection reconstruction (SD-FBP) while 35 patients matched for gender, age, body mass index and coronary artery calcifications underwent a novel high definition protocol with ASIR (HD-ASIR). Segment by segment image quality was assessed using a four-point scale (1 = excellent, 2 = good, 3 = moderate, 4 = non-diagnostic) and revealed better scores for HD-ASIR compared to SD-FBP (1.5 ± 0.43 vs. 1.8 ± 0.48; p < 0.05). The smallest detectable vessel diameter was also improved, 1.0 ± 0.5 mm for HD-ASIR as compared to 1.4 ± 0.4 mm for SD-FBP (p < 0.001). Average vessel attenuation was higher for HD-ASIR (388.3 ± 109.6 versus 350.6 ± 90.3 Hounsfield Units, HU; p < 0.05), while image noise, signal-to-noise ratio and contrast-to noise ratio did not differ significantly between reconstruction protocols (p = NS). The estimated effective radiation doses were similar, 2.3 ± 0.1 and 2.5 ± 0.1 mSv (HD-ASIR vs. SD-ASIR respectively). Compared to a standard definition backprojection protocol (SD-FBP), a newer high definition scan protocol in combination with ASIR (HD-ASIR) incrementally improved image quality and visualization of distal coronary artery segments in overweight and obese individuals, without increasing image noise and radiation dose.

Fiber Optic Communication System For Medical Images

NASA Astrophysics Data System (ADS)

Arenson, Ronald L.; Morton, Dan E.; London, Jack W.

1982-01-01

This paper discusses a fiber optic communication system linking ultrasound devices, Computerized tomography scanners, Nuclear Medicine computer system, and a digital fluoro-graphic system to a central radiology research computer. These centrally archived images are available for near instantaneous recall at various display consoles. When a suitable laser optical disk is available for mass storage, more extensive image archiving will be added to the network including digitized images of standard radiographs for comparison purposes and for remote display in such areas as the intensive care units, the operating room, and selected outpatient departments. This fiber optic system allows for a transfer of high resolution images in less than a second over distances exceeding 2,000 feet. The advantages of using fiber optic cables instead of typical parallel or serial communication techniques will be described. The switching methodology and communication protocols will also be discussed.

An integrated content and metadata based retrieval system for art.

PubMed

Lewis, Paul H; Martinez, Kirk; Abas, Fazly Salleh; Fauzi, Mohammad Faizal Ahmad; Chan, Stephen C Y; Addis, Matthew J; Boniface, Mike J; Grimwood, Paul; Stevenson, Alison; Lahanier, Christian; Stevenson, James

2004-03-01

A new approach to image retrieval is presented in the domain of museum and gallery image collections. Specialist algorithms, developed to address specific retrieval tasks, are combined with more conventional content and metadata retrieval approaches, and implemented within a distributed architecture to provide cross-collection searching and navigation in a seamless way. External systems can access the different collections using interoperability protocols and open standards, which were extended to accommodate content based as well as text based retrieval paradigms. After a brief overview of the complete system, we describe the novel design and evaluation of some of the specialist image analysis algorithms including a method for image retrieval based on sub-image queries, retrievals based on very low quality images and retrieval using canvas crack patterns. We show how effective retrieval results can be achieved by real end-users consisting of major museums and galleries, accessing the distributed but integrated digital collections.

Cost Analysis of the Addition of Hyperacute Magnetic Resonance Imaging for Selection of Patients for Endovascular Stroke Therapy.

PubMed

John, Seby; Thompson, Nicolas R; Lesko, Terry; Papesh, Nancy; Obuchowski, Nancy; Tomic, Dan; Wisco, Dolora; Khawaja, Zeshaun; Uchino, Ken; Man, Shumei; Cheng-Ching, Esteban; Toth, Gabor; Masaryk, Thomas; Ruggieri, Paul; Modic, Michael; Hussain, Muhammad Shazam

2017-10-01

Patient selection is important to determine the best candidates for endovascular stroke therapy. In application of a hyperacute magnetic resonance imaging (MRI) protocol for patient selection, we have shown decreased utilization with improved outcomes. A cost analysis comparing the pre- and post-MRI protocol time periods was performed to determine if the previous findings translated into cost opportunities. We retrospectively identified individuals considered for endovascular stroke therapy from January 2008 to August 2012 who were ≤8 h from stroke symptoms onset. Patients prior to April 30, 2010 were selected based on results of the computed tomography/computed tomography angiography alone (pre-hyperacute), whereas patients after April 30, 2010 were selected based on results of MRI (post-hyperacute MRI). Demographic, outcome, and financial information was collected. Log-transformed average daily direct costs were regressed on time period. The regression model included demographic and clinical covariates as potential confounders. Multiple imputation was used to account for missing data. We identified 267 patients in our database (88 patients in pre-hyperacute MRI period, 179 in hyperacute MRI protocol period). Patient length of stay was not significantly different in the hyperacute MRI protocol period as compared to the pre-hyperacute MRI period (10.6 vs. 9.9 days, p < 0.42). The median of average daily direct costs was reduced by 24.5% (95% confidence interval 14.1-33.7%, p < 0.001). Use of the hyperacute MRI protocol translated into reduced costs, in addition to reduced utilization and better outcomes. MRI selection of patients is an effective strategy, both for patients and hospital systems.

ACQ4: an open-source software platform for data acquisition and analysis in neurophysiology research.

PubMed

Campagnola, Luke; Kratz, Megan B; Manis, Paul B

2014-01-01

The complexity of modern neurophysiology experiments requires specialized software to coordinate multiple acquisition devices and analyze the collected data. We have developed ACQ4, an open-source software platform for performing data acquisition and analysis in experimental neurophysiology. This software integrates the tasks of acquiring, managing, and analyzing experimental data. ACQ4 has been used primarily for standard patch-clamp electrophysiology, laser scanning photostimulation, multiphoton microscopy, intrinsic imaging, and calcium imaging. The system is highly modular, which facilitates the addition of new devices and functionality. The modules included with ACQ4 provide for rapid construction of acquisition protocols, live video display, and customizable analysis tools. Position-aware data collection allows automated construction of image mosaics and registration of images with 3-dimensional anatomical atlases. ACQ4 uses free and open-source tools including Python, NumPy/SciPy for numerical computation, PyQt for the user interface, and PyQtGraph for scientific graphics. Supported hardware includes cameras, patch clamp amplifiers, scanning mirrors, lasers, shutters, Pockels cells, motorized stages, and more. ACQ4 is available for download at http://www.acq4.org.

Tuning of automatic exposure control strength in lumbar spine CT.

PubMed

D'Hondt, A; Cornil, A; Bohy, P; De Maertelaer, V; Gevenois, P A; Tack, D

2014-05-01

To investigate the impact of tuning the automatic exposure control (AEC) strength curve (specific to Care Dose 4D®; Siemens Healthcare, Forchheim, Germany) from "average" to "strong" on image quality, radiation dose and operator dependency during lumbar spine CT examinations. Two hospitals (H1, H2), both using the same scanners, were considered for two time periods (P1 and P2). During P1, the AEC curve was "average" and radiographers had to select one of two protocols according to the body mass index (BMI): "standard" if BMI <30.0 kg m(-2) (120 kV-330 mAs) or "large" if BMI >30.0 kg m(-2) (140 kV-280 mAs). During P2, the AEC curve was changed to "strong", and all acquisitions were obtained with one protocol (120 kV and 270 mAs). Image quality was scored and patients' diameters calculated for both periods. 497 examinations were analysed. There was no significant difference in mean diameters according to hospitals and periods (p > 0.801) and in quality scores between periods (p > 0.172). There was a significant difference between hospitals regarding how often the "large" protocol was assigned [13 (10%)/132 patients in H1 vs 37 (28%)/133 in H2] (p < 0.001). During P1, volume CT dose index (CTDIvol) was higher in H2 (+13%; p = 0.050). In both hospitals, CTDIvol was reduced between periods (-19.2% in H1 and -29.4% in H2; p < 0.001). An operator dependency in protocol selection, unexplained by patient diameters or highlighted by image quality scores, has been observed. Tuning the AEC curve from average to strong enables suppression of the operator dependency in protocol selection and related dose increase, while preserving image quality. CT acquisition protocols based on weight are responsible for biases in protocol selection. Using an appropriate AEC strength curve reduces the number of protocols to one. Operator dependency of protocol selection is thereby eliminated.

A harmonized segmentation protocol for hippocampal and parahippocampal subregions: why do we need one and what are the key goals?

PubMed Central

Olsen, Rosanna K.; Berron, David; Carr, Valerie A.; Stark, Craig E.L.; Amaral, Robert S.C.; Amunts, Katrin; Augustinack, Jean C.; Bender, Andrew R.; Bernstein, Jeffrey D.; Boccardi, Marina; Bocchetta, Martina; Burggren, Alison; Chakravarty, M. Mallar; Chupin, Marie; Ekstrom, Arne; de Flores, Robin; Insausti, Ricardo; Kanel, Prabesh; Kedo, Olga; Kennedy, Kristen M.; Kerchner, Geoffrey A.; LaRocque, Karen F.; Liu, Xiuwen; Maass, Anne; Malykhin, Nicolai; Mueller, Susanne G.; Ofen, Noa; Palombo, Daniela J.; Parekh, Mansi B.; Pluta, John B.; Pruessner, Jens C.; Raz, Naftali; Rodrigue, Karen M.; Schoemaker, Dorothee; Shafer, Andrea T.; Steve, Trevor A.; Suthana, Nanthia; Wang, Lei; Winterburn, Julie L.; Yassa, Michael A.; Yushkevich, Paul A.; la Joie, Renaud

2016-01-01

The advent of high-resolution magnetic resonance imaging (MRI) has enabled in vivo research in a variety of populations and diseases on the structure and function of hippocampal subfields and subdivisions of the parahippocampal gyrus. Due to the many extant and highly discrepant segmentation protocols, comparing results across studies is difficult. To overcome this barrier, the Hippocampal Subfields Group was formed as an international collaboration with the aim of developing a harmonized protocol for manual segmentation of hippocampal and parahippocampal subregions on high-resolution MRI. In this commentary we discuss the goals for this protocol and the associated key challenges involved in its development. These include differences among existing anatomical reference materials, striking the right balance between reliability of measurements and anatomical validity, and the development of a versatile protocol that can be adopted for the study of populations varying in age and health. The commentary outlines these key challenges, as well as the proposed solution of each, with concrete examples from our working plan. Finally, with two examples, we illustrate how the harmonized protocol, once completed, is expected to impact the field by producing measurements that are quantitatively comparable across labs and by facilitating the synthesis of findings across different studies. PMID:27862600

A GIS-based protocol for the simulation and evaluation of realistic 3-D thinning scenarios in recreational forest management.

PubMed

Lin, Chinsu; Thomson, Gavin; Hung, Shih-Hsiang; Lin, Yu-Dung

2012-12-30

This study introduces a GIS-based protocol for the simulation and evaluation of thinning treatments in recreational forest management. The protocol was implemented in a research study based on an area of recreational forest in Alishan National Scenic Area, Taiwan. Ground survey data were mapped to a GIS database, to create a precise, yet flexible, GIS-based digital forest. The digital forest model was used to generate 18 different thinning scenario images and one image of the existing unthinned forest. A questionnaire was completed by 456 participants while simultaneously viewing the scenario images. The questionnaire was used to determine the scenic beauty preferences of the respondents. Statistical analysis of the data revealed that the respondents preferred low density, upper-storey thinning treatments and a dispersed retention pattern of the remaining trees. High density upper-storey treatments evoked a strongly negative reaction in the observers. The experiment demonstrated that the proposed protocol is suitable for selecting an appropriate thinning strategy for recreational forest and that the protocol has practical value in recreational forest management. Copyright © 2012 Elsevier Ltd. All rights reserved.

Application of 80-kVp scan and raw data-based iterative reconstruction for reduced iodine load abdominal-pelvic CT in patients at risk of contrast-induced nephropathy referred for oncological assessment: effects on radiation dose, image quality and renal function.

PubMed

Nagayama, Yasunori; Tanoue, Shota; Tsuji, Akinori; Urata, Joji; Furusawa, Mitsuhiro; Oda, Seitaro; Nakaura, Takeshi; Utsunomiya, Daisuke; Yoshida, Eri; Yoshida, Morikatsu; Kidoh, Masafumi; Tateishi, Machiko; Yamashita, Yasuyuki

2018-05-01

To evaluate the image quality, radiation dose, and renal safety of contrast medium (CM)-reduced abdominal-pelvic CT combining 80-kVp and sinogram-affirmed iterative reconstruction (SAFIRE) in patients with renal dysfunction for oncological assessment. We included 45 patients with renal dysfunction (estimated glomerular filtration rate  <45 ml per min per 1.73 m 2 ) who underwent reduced-CM abdominal-pelvic CT (360 mgI kg -1 , 80-kVp, SAFIRE) for oncological assessment. Another 45 patients without renal dysfunction (estimated glomerular filtration rate >60 ml per lmin per 1.73 m 2 ) who underwent standard oncological abdominal-pelvic CT (600 mgI kg -1 , 120-kVp, filtered-back projection) were included as controls. CT attenuation, image noise, and contrast-to-noise ratio (CNR) were compared. Two observers performed subjective image analysis on a 4-point scale. Size-specific dose estimate and renal function 1-3 months after CT were measured. The size-specific dose estimate and iodine load of 80-kVp protocol were 32 and 41%,, respectively, lower than of 120-kVp protocol (p < 0.01). CT attenuation and contrast-to-noise ratio of parenchymal organs and vessels in 80-kVp images were significantly better than those of 120-kVp images (p < 0.05). There were no significant differences in quantitative or qualitative image noise or subjective overall quality (p > 0.05). No significant kidney injury associated with CM administration was observed. 80-kVp abdominal-pelvic CT with SAFIRE yields diagnostic image quality in oncology patients with renal dysfunction under substantially reduced iodine and radiation dose without renal safety concerns. Advances in knowledge: Using 80-kVp and SAFIRE allows for 40% iodine load and 32% radiation dose reduction for abdominal-pelvic CT without compromising image quality and renal function in oncology patients at risk of contrast-induced nephropathy.

Management of obstetric hemorrhage.

PubMed

Shevell, Tracy; Malone, Fergal D

2003-02-01

A reluctance to proceed with hysterectomy for obstetric hemorrhage may be a more likely cause of preventable death in obstetrics than a lack of surgical or medical skills. Every obstetric unit should have protocols available to deal with hemorrhage and, in addition, have specific guidelines for patients who object to blood transfusions for various reasons. Risk factors for hemorrhage should be identified antenatally, using all possible imaging modalities available, and utilizing multidisciplinary resources whenever possible. Novel strategies for prenatal diagnosis of abnormal placentation include advanced sonography and magnetic resonance imaging. Placement and utilization of arterial catheters for uterine artery embolization is becoming more widespread and new surgical technology such as the argon beam coagulator seems promising. When intra or postpartum hemorrhage is encountered, a familiar protocol for dealing with blood loss should be triggered. Timely hysterectomy should be performed for signs of refractory bleeding. Application of medical and surgical principles combined with recent technologic advances will help the obstetrician avoid disastrous outcomes for both mother and fetus.

Internet-based videoconferencing and data collaboration for the imaging community.

PubMed

Poon, David P; Langkals, John W; Giesel, Frederik L; Knopp, Michael V; von Tengg-Kobligk, Hendrik

2011-01-01

Internet protocol-based digital data collaboration with videoconferencing is not yet well utilized in the imaging community. Videoconferencing, combined with proven low-cost solutions, can provide reliable functionality and speed, which will improve rapid, time-saving, and cost-effective communications, within large multifacility institutions or globally with the unlimited reach of the Internet. The aim of this project was to demonstrate the implementation of a low-cost hardware and software setup that facilitates global data collaboration using WebEx and GoToMeeting Internet protocol-based videoconferencing software. Both products' features were tested and evaluated for feasibility across 2 different Internet networks, including a video quality and recording assessment. Cross-compatibility with an Apple OS is also noted in the evaluations. Departmental experiences with WebEx pertaining to clinical trials are also described. Real-time remote presentation of dynamic data was generally consistent across platforms. A reliable and inexpensive hardware and software setup for complete Internet-based data collaboration/videoconferencing can be achieved.

A technique for automatically extracting useful field of view and central field of view images.

PubMed

Pandey, Anil Kumar; Sharma, Param Dev; Aheer, Deepak; Kumar, Jay Prakash; Sharma, Sanjay Kumar; Patel, Chetan; Kumar, Rakesh; Bal, Chandra Sekhar

2016-01-01

It is essential to ensure the uniform response of the single photon emission computed tomography gamma camera system before using it for the clinical studies by exposing it to uniform flood source. Vendor specific acquisition and processing protocol provide for studying flood source images along with the quantitative uniformity parameters such as integral and differential uniformity. However, a significant difficulty is that the time required to acquire a flood source image varies from 10 to 35 min depending both on the activity of Cobalt-57 flood source and the pre specified counts in the vendors protocol (usually 4000K-10,000K counts). In case the acquired total counts are less than the total prespecified counts, and then the vendor's uniformity processing protocol does not precede with the computation of the quantitative uniformity parameters. In this study, we have developed and verified a technique for reading the flood source image, remove unwanted information, and automatically extract and save the useful field of view and central field of view images for the calculation of the uniformity parameters. This was implemented using MATLAB R2013b running on Ubuntu Operating system and was verified by subjecting it to the simulated and real flood sources images. The accuracy of the technique was found to be encouraging, especially in view of practical difficulties with vendor-specific protocols. It may be used as a preprocessing step while calculating uniformity parameters of the gamma camera in lesser time with fewer constraints.

Image-based Lagrangian Particle Tracking in Bed-load Experiments.

PubMed

Radice, Alessio; Sarkar, Sankar; Ballio, Francesco

2017-07-20

Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions at a relatively low cost. This manuscript describes an application of particle tracking velocimetry (PTV) to a bed-load experiment with lightweight sediment. The key characteristics of the investigated sediment transport conditions were the presence of a covered flow and of a fixed rough bed above which particles were released in limited number at the flume inlet. Under the applied flow conditions, the motion of the individual bed-load particles was intermittent, with alternating movement and stillness terms. The flow pattern was preliminarily characterized by acoustic measurements of vertical profiles of the stream-wise velocity. During process visualization, a large field of view was obtained using two action-cameras placed at different locations along the flume. The experimental protocol is described in terms of channel calibration, experiment realization, image pre-processing, automatic particle tracking, and post-processing of particle track data from the two cameras. The presented proof-of-concept results include probability distributions of the particle hop length and duration. The achievements of this work are compared to those of existing literature to demonstrate the validity of the protocol.

Cerebral microbleeds, cognitive impairment, and MRI in patients with diabetes mellitus.

PubMed

Zhou, Hong; Yang, Juan; Xie, Peihan; Dong, Yulan; You, Yong; Liu, Jincai

2017-07-01

Cerebral microbleeds (CMBs), a typical imaging manifestation marker of sporadic cerebral small vessel disease, play a critical role in vascular cognitive impairment, which is often accompanied by diabetes mellitus (DM). Hence, CMBs may, in part, be responsible for the occurrence and development of cognitive impairment in patients with diabetes. Novel magnetic resonance imaging (MRI) sequences, such as susceptibility-weighted imaging and T2*-weighted gradient-echo, have the capability of noninvasively revealing CMBs in the brain. Moreover, a correlation between CMBs and cognitive impairment in patients with diabetes has been suggested in applications of functional MRI (fMRI). Since pathological changes in the brain occur prior to observable decline in cognitive function, neuroimaging may help predict the progression of cognitive impairment in diabetic patients. In this article, we review the detection of CMBs using MRI in diabetic patients exhibiting cognitive impairment. Future studies should emphasize the development and establishment of a novel MRI protocol, including fMRI, for diabetic patients with cognitive impairment to detect CMBs. A reliable MRI protocol would also be helpful in understanding the pathological mechanisms of cognitive impairment in this important patient population. Copyright © 2017. Published by Elsevier B.V.

Simultaneous diffuse near-infrared imaging of hemodynamic and oxygenation changes and electroencephalographic measurements of neuronal activity in the human brain

NASA Astrophysics Data System (ADS)

Noponen, Tommi; Kicic, Dubravko; Kotilahti, Kalle; Kajava, Timo; Kahkonen, Seppo; Nissila, Ilkka; Merilainen, Pekka; Katila, Toivo

2005-04-01

Visually evoked hemodynamic responses and potentials were simultaneously measured using a 16-channel optical imaging instrument and a 60-channel electroencephalography instrument during normo-, hypo- and hypercapnia from three subjects. Flashing and pattern-reversed checkerboard stimuli were used. The study protocol included two counterbalanced measurements during both normo- and hypocapnia and normo- and hypercapnia. Hypocapnia was produced by controlled hyperventilation and hypercapnia by breathing carbon dioxide enriched air. Near-infrared imaging was also used to monitor the concentration changes of oxy- and deoxyhaemoglobin due to hypo- and hypercapnia. Hemodynamic responses and evoked potentials were successfully detected for each subject above the visual cortex. The latencies of the hemodynamic responses during hypocapnia were shorter whereas during hypercapnia they were longer when compared to the latencies during normocapnia. Hypocapnia tended to decrease the latencies of visually evoked potentials compared to those during normocapnia while hypercapnia did not show any consistent effect to the potentials. The developed measurement setup and the study protocol provide the opportunity to investigate the neurovascular coupling and the links between the baseline level of blood flow, electrical activity and hemodynamic responses in the human brain.

Effects of protocol step length on biomechanical measures in swimming.

PubMed

Barbosa, Tiago M; de Jesus, Kelly; Abraldes, J Arturo; Ribeiro, João; Figueiredo, Pedro; Vilas-Boas, João Paulo; Fernandes, Ricardo J

2015-03-01

The assessment of energetic and mechanical parameters in swimming often requires the use of an intermittent incremental protocol, whose step lengths are corner stones for the efficiency of the evaluation procedures. To analyze changes in swimming kinematics and interlimb coordination behavior in 3 variants, with different step lengths, of an intermittent incremental protocol. Twenty-two male swimmers performed n×di variants of an intermittent and incremental protocol (n≤7; d1=200 m, d2=300 m, and d3=400 m). Swimmers were videotaped in the sagittal plane for 2-dimensional kinematical analysis using a dual-media setup. Video images were digitized with a motion-capture system. Parameters that were assessed included the stroke kinematics, the segmental and anatomical landmark kinematics, and interlimb coordination. Movement efficiency was also estimated. There were no significant variations in any of the selected variables according to the step lengths. A high to very high relationship was observed between step lengths. The bias was much reduced and the 95%CI fairly tight. Since there were no meaningful differences between the 3 protocol variants, the 1 with shortest step length (ie, 200 m) should be adopted for logistical reasons.

Low-dose head computed tomography in children: a single institutional experience in pediatric radiation risk reduction: clinical article.

PubMed

Morton, Ryan P; Reynolds, Renee M; Ramakrishna, Rohan; Levitt, Michael R; Hopper, Richard A; Lee, Amy; Browd, Samuel R

2013-10-01

In this study, the authors describe their experience with a low-dose head CT protocol for a preselected neurosurgical population at a dedicated pediatric hospital (Seattle Children's Hospital), the largest number of patients with this protocol reported to date. All low-dose head CT scans between October 2011 and November 2012 were reviewed. Two different low-dose radiation dosages were used, at one-half or one-quarter the dose of a standard head CT scan, based on patient characteristics agreed upon by the neurosurgery and radiology departments. Patient information was also recorded, including diagnosis and indication for CT scan. Six hundred twenty-four low-dose head CT procedures were performed within the 12-month study period. Although indications for the CT scans varied, the most common reason was to evaluate the ventricles and catheter placement in hydrocephalic patients with shunts (70%), followed by postoperative craniosynostosis imaging (12%). These scans provided adequate diagnostic imaging, and no patient required a follow-up full-dose CT scan as a result of poor image quality on a low-dose CT scan. Overall physician comfort and satisfaction with interpretation of the images was high. An additional 2150 full-dose head CT scans were performed during the same 12-month time period, making the total number of CT scans 2774. This value compares to 3730 full-dose head CT scans obtained during the year prior to the study when low-dose CT and rapid-sequence MRI was not a reliable option at Seattle Children's Hospital. Thus, over a 1-year period, 22% of the total CT scans were able to be converted to low-dose scans, and full-dose CT scans were able to be reduced by 42%. The implementation of a low-dose head CT protocol substantially reduced the amount of ionizing radiation exposure in a preselected population of pediatric neurosurgical patients. Image quality and diagnostic utility were not significantly compromised.

Urinary calculi composed of uric acid, cystine, and mineral salts: differentiation with dual-energy CT at a radiation dose comparable to that of intravenous pyelography.

PubMed

Thomas, Christoph; Heuschmid, Martin; Schilling, David; Ketelsen, Dominik; Tsiflikas, Ilias; Stenzl, Arnulf; Claussen, Claus D; Schlemmer, Heinz-Peter

2010-11-01

To retrospectively evaluate radiation dose, image quality, and the ability to differentiate urinary calculi of differing compositions by using low-dose dual-energy computed tomography (CT). The institutional review board approved this retrospective study; informed consent was waived. A low-dose dual-energy CT protocol (tube voltage and reference effective tube current-time product, 140 kV and 23 mAs and 80 kV and 105 mAs; collimation, 64 × 0.6 mm; pitch, 0.7) for the detection of urinary calculi was implemented into routine clinical care. All patients (n = 112) who were examined with this protocol from July 2008 to August 2009 were included. The composition of urinary calculi was assessed by using commercially available postprocessing software and was compared with results of the reference standard (ex vivo infrared spectroscopy) in 40 patients for whom the reference standard was available. Effective doses were calculated. Image quality was rated subjectively and objectively and was correlated with patient size expressed as body cross-sectional area at the level of acquisition by using Spearman correlation coefficients. One calcified concrement in the distal ureter of an obese patient was mistakenly interpreted as mixed calcified and uric acid. One struvite calculus was falsely interpreted as cystine. All other uric acid, cystine, and calcium-containing calculi were correctly identified by using dual-energy CT. The mean radiation dose was 2.7 mSv. The average image quality was rated as acceptable, with a decrease in image quality in larger patients. Low-dose unenhanced dual-source dual-energy CT can help differentiate between calcified, uric acid, and cystine calculi at a radiation dose comparable to that of conventional intravenous pyelography. Because of decreased image quality in obese patients, only nonobese patients should be examined with this protocol. © RSNA, 2010.

MR Imaging of the Penis and Scrotum.

PubMed

Parker, Rex A; Menias, Christine O; Quazi, Robin; Hara, Amy K; Verma, Sadhna; Shaaban, Akram; Siegel, Cary L; Radmanesh, Alireza; Sandrasegaran, Kumar

2015-01-01

Traditionally, due to its low cost, ready availability, and proved diagnostic accuracy, ultrasonography (US) has been the primary imaging modality for the evaluation of scrotal and, to a lesser extent, penile disease. However, US is limited by its relatively small useful field of view, operator dependence, and inability to provide much information on tissue characterization. Magnetic resonance (MR) imaging, with its excellent soft-tissue contrast and good spatial resolution, is increasingly being used as both a problem-solving tool in patients who have already undergone US and as a primary modality for the evaluation of suspected disease. Specifically, MR imaging can aid in differentiating between benign and malignant lesions seen at US, help define the extent of inflammatory processes or traumatic injuries, and play a vital role in locoregional staging of tumors. Consequently, it is becoming more important for radiologists to be familiar with the wide range of penile and scrotal disease entities and their MR imaging appearances. The authors review the basic anatomy of the penis and scrotum as seen at MR imaging and provide a basic protocol for penile and scrotal imaging, with emphasis on the advantages of MR imaging. Pathologic processes are organized into traumatic (including penile fracture and contusion), infectious or inflammatory (including Fournier gangrene and scrotal abscess), and neoplastic (including both benign and malignant scrotal and penile tumors) processes. ©RSNA, 2015.

Optimized imaging of the midface and orbits

PubMed Central

Langner, Sönke

2015-01-01

A variety of imaging techniques are available for imaging the midface and orbits. This review article describes the different imaging techniques based on the recent literature and discusses their impact on clinical routine imaging. Imaging protocols are presented for different diseases and the different imaging modalities. PMID:26770279

Combining Image and Non-Image Data for Automatic Detection of Retina Disease in a Telemedicine Network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aykac, Deniz; Chaum, Edward; Fox, Karen

A telemedicine network with retina cameras and automated quality control, physiological feature location, and lesion/anomaly detection is a low-cost way of achieving broad-based screening for diabetic retinopathy (DR) and other eye diseases. In the process of a routine eye-screening examination, other non-image data is often available which may be useful in automated diagnosis of disease. In this work, we report on the results of combining this non-image data with image data, using the protocol and processing steps of a prototype system for automated disease diagnosis of retina examinations from a telemedicine network. The system includes quality assessments, automated physiology detection,more » and automated lesion detection to create an archive of known cases. Non-image data such as diabetes onset date and hemoglobin A1c (HgA1c) for each patient examination are included as well, and the system is used to create a content-based image retrieval engine capable of automated diagnosis of disease into 'normal' and 'abnormal' categories. The system achieves a sensitivity and specificity of 91.2% and 71.6% using hold-one-out validation testing.« less

Effect of attenuation correction on image quality in emission tomography

NASA Astrophysics Data System (ADS)

Denisova, N. V.; Ondar, M. M.

2017-10-01

In this paper, mathematical modeling and computer simulations of myocardial perfusion SPECT imaging are performed. The main factors affecting the quality of reconstructed images in SPECT are anatomical structures, the diastolic volume of a myocardium and attenuation of gamma rays. The purpose of the present work is to study the effect of attenuation correction on image quality in emission tomography. The basic 2D model describing a Tc-99m distribution in a transaxial slice of the thoracic part of a patient body was designed. This model was used to construct four phantoms simulated various anatomical shapes: 2 male and 2 female patients with normal, obese and subtle physique were included in the study. Data acquisition model which includes the effect of non-uniform attenuation, collimator-detector response and Poisson statistics was developed. The projection data were calculated for 60 views in accordance with the standard myocardial perfusion SPECT imaging protocol. Reconstructions of images were performed using the OSEM algorithm which is widely used in modern SPECT systems. Two types of patient's examination procedures were simulated: SPECT without attenuation correction and SPECT/CT with attenuation correction. The obtained results indicate a significant effect of the attenuation correction on the SPECT images quality.

Diffusion-weighted Breast MRI: Clinical Applications and Emerging Techniques

PubMed Central

Partridge, Savannah C.; Nissan, Noam; Rahbar, Habib; Kitsch, Averi E.; Sigmund, Eric E.

2016-01-01

Diffusion weighted MRI (DWI) holds potential to improve the detection and biological characterization of breast cancer. DWI is increasingly being incorporated into breast MRI protocols to address some of the shortcomings of routine clinical breast MRI. Potential benefits include improved differentiation of benign and malignant breast lesions, assessment and prediction of therapeutic efficacy, and non-contrast detection of breast cancer. The breast presents a unique imaging environment with significant physiologic and inter-subject variations, as well as specific challenges to achieving reliable high quality diffusion weighted MR images. Technical innovations are helping to overcome many of the image quality issues that have limited widespread use of DWI for breast imaging. Advanced modeling approaches to further characterize tissue perfusion, complexity, and glandular organization may expand knowledge and yield improved diagnostic tools. PMID:27690173

Laser scanning confocal microscopy: history, applications, and related optical sectioning techniques.

PubMed

Paddock, Stephen W; Eliceiri, Kevin W

2014-01-01

Confocal microscopy is an established light microscopical technique for imaging fluorescently labeled specimens with significant three-dimensional structure. Applications of confocal microscopy in the biomedical sciences include the imaging of the spatial distribution of macromolecules in either fixed or living cells, the automated collection of 3D data, the imaging of multiple labeled specimens and the measurement of physiological events in living cells. The laser scanning confocal microscope continues to be chosen for most routine work although a number of instruments have been developed for more specific applications. Significant improvements have been made to all areas of the confocal approach, not only to the instruments themselves, but also to the protocols of specimen preparation, to the analysis, the display, the reproduction, sharing and management of confocal images using bioinformatics techniques.

Referral Patterns for Chronic Groin Pain and Athletic Pubalgia/Sports Hernia: Magnetic Resonance Imaging Findings, Treatment, and Outcomes.

PubMed

Zoland, Mark P; Maeder, Matthew E; Iraci, Joseph C; Klein, Devon A

Chronic groin pain is a common problem and has been well-described in high-performance athletes. Its presentation in the recreational athlete has been less frequently described. We present the experience of a tertiary group of physicians specializing in groin pain and athletic pubalgia. Dynamic magnetic resonance imaging (MRI) protocol was employed. Surgery was performed in patients failing non-surgical management. A retrospective review was performed. Of 117 mostly non-professional athletes, there were 79 MRI-positive cases of athletic pubalgia (68%). Other common findings were acetabular labral tear (57%) and inguinal hernia (35%). Employment of a dynamic MRI protocol increased sensitivity for certain pathologies. Of positive athletic pubalgia cases, 49% went on to have surgical repair. The satisfaction rate in the surgical group was 90% at follow up. Advances in MRI have increased our ability to characterize and diagnose specific injuries causing groin pain. We present our diagnostic algorithm, including an MRI protocol that not only evaluates the groin, but has increased sensitivity for additional findings such as inguinal hernia and abdominal wall deficiencies. A targeted work-up and subsequent surgical treatment in the appropriate patient, even in the recreational athletic population, has yielded a 90% satisfaction rate.

Demonstrating a Realistic IP Mission Prototype

NASA Technical Reports Server (NTRS)

Rash, James; Ferrer, Arturo B.; Goodman, Nancy; Ghazi-Tehrani, Samira; Polk, Joe; Johnson, Lorin; Menke, Greg; Miller, Bill; Criscuolo, Ed; Hogie, Keith

2003-01-01

Flight software and hardware and realistic space communications environments were elements of recent demonstrations of the Internet Protocol (IP) mission concept in the lab. The Operating Missions as Nodes on the Internet (OMNI) Project and the Flight Software Branch at NASA/GSFC collaborated to build the prototype of a representative space mission that employed unmodified off-the-shelf Internet protocols and technologies for end-to-end communications between the spacecraft/instruments and the ground system/users. The realistic elements used in the prototype included an RF communications link simulator and components of the TRIANA mission flight software and ground support system. A web-enabled camera connected to the spacecraft computer via an Ethernet LAN represented an on-board instrument creating image data. In addition to the protocols at the link layer (HDLC), transport layer (UDP, TCP), and network (IP) layer, a reliable file delivery protocol (MDP) at the application layer enabled reliable data delivery both to and from the spacecraft. The standard Network Time Protocol (NTP) performed on-board clock synchronization with a ground time standard. The demonstrations of the prototype mission illustrated some of the advantages of using Internet standards and technologies for space missions, but also helped identify issues that must be addressed. These issues include applicability to embedded real-time systems on flight-qualified hardware, range of applicability of TCP, and liability for and maintenance of commercial off-the-shelf (COTS) products. The NASA Earth Science Technology Office (ESTO) funded the collaboration to build and demonstrate the prototype IP mission.

Optimization of a secondary VOI protocol for lung imaging in a clinical CT scanner.

PubMed

Larsen, Thomas C; Gopalakrishnan, Vissagan; Yao, Jianhua; Nguyen, Catherine P; Chen, Marcus Y; Moss, Joel; Wen, Han

2018-05-21

We present a solution to meet an unmet clinical need of an in-situ "close look" at a pulmonary nodule or at the margins of a pulmonary cyst revealed by a primary (screening) chest CT while the patient is still in the scanner. We first evaluated options available on current whole-body CT scanners for high resolution screening scans, including ROI reconstruction of the primary scan data and HRCT, but found them to have insufficient SNR in lung tissue or discontinuous slice coverage. Within the capabilities of current clinical CT systems, we opted for the solution of a secondary, volume-of-interest (VOI) protocol where the radiation dose is focused into a short-beam axial scan at the z position of interest, combined with a small-FOV reconstruction at the xy position of interest. The objective of this work was to design a VOI protocol that is optimized for targeted lung imaging in a clinical whole-body CT system. Using a chest phantom containing a lung-mimicking foam insert with a simulated cyst, we identified the appropriate scan mode and optimized both the scan and recon parameters. The VOI protocol yielded 3.2 times the texture amplitude-to-noise ratio in the lung-mimicking foam when compared to the standard chest CT, and 8.4 times the texture difference between the lung mimicking and reference foams. It improved details of the wall of the simulated cyst and better resolution in a line-pair insert. The Effective Dose of the secondary VOI protocol was 42% on average and up to 100% in the worst-case scenario of VOI positioning relative to the standard chest CT. The optimized protocol will be used to obtain detailed CT textures of pulmonary lesions, which are biomarkers for the type and stage of lung diseases. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

A 32-Channel Phased-Array Receive with Asymmetric Birdcage Transmit RF Coil for Hyperpolarized Xenon-129 Lung Imaging

PubMed Central

Dregely, Isabel; Ruset, Iulian C.; Wiggins, Graham; Mareyam, Azma; Mugler, John P.; Altes, Talissa A.; Meyer, Craig; Ruppert, Kai; Wald, Lawrence L.; Hersman, F. William

2012-01-01

Hyperpolarized xenon-129 (HP Xe) has the potential to become a non-invasive contrast agent for lung MRI. In addition to its utility for imaging of ventilated airspaces, the property of xenon to dissolve in lung tissue and blood upon inhalation provides the opportunity to study gas exchange. Implementations of imaging protocols for obtaining regional parameters that exploit the dissolved phase are limited by the available signal-to-noise ratio (SNR), excitation homogeneity, and length of acquisition times. To address these challenges, a 32-channel receive-array coil complemented by an asymmetric birdcage transmit coil tuned to the HP Xe resonance at 3T was developed. First results of spin-density imaging in healthy subjects and subjects with obstructive lung disease demonstrated the improvements in image quality by high resolution ventilation images with high SNR. Parallel imaging performance of the phased-array coil was demonstrated by acceleration factors up to three in 2D acquisitions and up to six in 3D acquisitions. Transmit-field maps showed a regional variation of only 8% across the whole lung. The newly developed phased-array receive coil with the birdcage transmit coil will lead to an improvement in existing imaging protocols, but moreover enable the development of new, functional lung imaging protocols based on the improvements in excitation homogeneity, SNR, and acquisition speed. PMID:23132336

New Imaging Strategies Using a Motion-Resistant Liver Sequence in Uncooperative Patients

PubMed Central

Kim, Bong Soo; Lee, Kyung Ryeol; Goh, Myeng Ju

2014-01-01

MR imaging has unique benefits for evaluating the liver because of its high-resolution capability and ability to permit detailed assessment of anatomic lesions. In uncooperative patients, motion artifacts can impair the image quality and lead to the loss of diagnostic information. In this setting, the recent advances in motion-resistant liver MR techniques, including faster imaging protocols (e.g., dual-echo magnetization-prepared rapid-acquisition gradient echo (MP-RAGE), view-sharing technique), the data under-sampling (e.g., gradient recalled echo (GRE) with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), single-shot echo-train spin-echo (SS-ETSE)), and motion-artifact minimization method (e.g., radial GRE with/without k-space-weighted image contrast (KWIC)), can provide consistent, artifact-free images with adequate image quality and can lead to promising diagnostic performance. Understanding of the different motion-resistant options allows radiologists to adopt the most appropriate technique for their clinical practice and thereby significantly improve patient care. PMID:25243115

Limiting CT radiation dose in children with craniosynostosis: phantom study using model-based iterative reconstruction.

PubMed

Kaasalainen, Touko; Palmu, Kirsi; Lampinen, Anniina; Reijonen, Vappu; Leikola, Junnu; Kivisaari, Riku; Kortesniemi, Mika

2015-09-01

Medical professionals need to exercise particular caution when developing CT scanning protocols for children who require multiple CT studies, such as those with craniosynostosis. To evaluate the utility of ultra-low-dose CT protocols with model-based iterative reconstruction techniques for craniosynostosis imaging. We scanned two pediatric anthropomorphic phantoms with a 64-slice CT scanner using different low-dose protocols for craniosynostosis. We measured organ doses in the head region with metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters. Numerical simulations served to estimate organ and effective doses. We objectively and subjectively evaluated the quality of images produced by adaptive statistical iterative reconstruction (ASiR) 30%, ASiR 50% and Veo (all by GE Healthcare, Waukesha, WI). Image noise and contrast were determined for different tissues. Mean organ dose with the newborn phantom was decreased up to 83% compared to the routine protocol when using ultra-low-dose scanning settings. Similarly, for the 5-year phantom the greatest radiation dose reduction was 88%. The numerical simulations supported the findings with MOSFET measurements. The image quality remained adequate with Veo reconstruction, even at the lowest dose level. Craniosynostosis CT with model-based iterative reconstruction could be performed with a 20-μSv effective dose, corresponding to the radiation exposure of plain skull radiography, without compromising required image quality.

Development of an acquisition protocol and a segmentation algortihm for wounds of cutaneous Leishmaniasis in digital images

NASA Astrophysics Data System (ADS)

Diaz, Kristians; Castañeda, Benjamín; Miranda, César; Lavarello, Roberto; Llanos, Alejandro

2010-03-01

We developed a protocol for the acquisition of digital images and an algorithm for a color-based automatic segmentation of cutaneous lesions of Leishmaniasis. The protocol for image acquisition provides control over the working environment to manipulate brightness, lighting and undesirable shadows on the injury using indirect lighting. Also, this protocol was used to accurately calculate the area of the lesion expressed in mm2 even in curved surfaces by combining the information from two consecutive images. Different color spaces were analyzed and compared using ROC curves in order to determine the color layer with the highest contrast between the background and the wound. The proposed algorithm is composed of three stages: (1) Location of the wound determined by threshold and mathematical morphology techniques to the H layer of the HSV color space, (2) Determination of the boundaries of the wound by analyzing the color characteristics in the YIQ space based on masks (for the wound and the background) estimated from the first stage, and (3) Refinement of the calculations obtained on the previous stages by using the discrete dynamic contours algorithm. The segmented regions obtained with the algorithm were compared with manual segmentations made by a medical specialist. Broadly speaking, our results support that color provides useful information during segmentation and measurement of wounds of cutaneous Leishmaniasis. Results from ten images showed 99% specificity, 89% sensitivity, and 98% accuracy.

High-Resolution 3T MR Imaging of the Triangular Fibrocartilage Complex

PubMed Central

von Borstel, Donald; Wang, Michael; Small, Kirstin; Nozaki, Taiki; Yoshioka, Hiroshi

2017-01-01

This study is intended as a review of 3Tesla (T) magnetic resonance (MR) imaging of the triangular fibrocartilage complex (TFCC). The recent advances in MR imaging, which includes high field strength magnets, multi-channel coils, and isotropic 3-dimensional (3D) sequences have enabled the visualization of precise TFCC anatomy with high spatial and contrast resolution. In addition to the routine wrist protocol, there are specific techniques used to optimize 3T imaging of the wrist; including driven equilibrium sequence (DRIVE), parallel imaging, and 3D imaging. The coil choice for 3T imaging of the wrist depends on a number of variables, and the proper coil design selection is critical for high-resolution wrist imaging with high signal and contrast-to-noise ratio. The TFCC is a complex structure and is composed of the articular disc (disc proper), the triangular ligament, the dorsal and volar radioulnar ligaments, the meniscus homologue, the ulnar collateral ligament (UCL), the extensor carpi ulnaris (ECU) tendon sheath, and the ulnolunate and ulnotriquetral ligaments. The Palmer classification categorizes TFCC lesions as traumatic (type 1) or degenerative (type 2). In this review article, we present clinical high-resolution MR images of normal TFCC anatomy and TFCC injuries with this classification system. PMID:27535592

High-Resolution 3T MR Imaging of the Triangular Fibrocartilage Complex.

PubMed

von Borstel, Donald; Wang, Michael; Small, Kirstin; Nozaki, Taiki; Yoshioka, Hiroshi

2017-01-10

This study is intended as a review of 3Tesla (T) magnetic resonance (MR) imaging of the triangular fibrocartilage complex (TFCC). The recent advances in MR imaging, which includes high field strength magnets, multi-channel coils, and isotropic 3-dimensional (3D) sequences have enabled the visualization of precise TFCC anatomy with high spatial and contrast resolution. In addition to the routine wrist protocol, there are specific techniques used to optimize 3T imaging of the wrist; including driven equilibrium sequence (DRIVE), parallel imaging, and 3D imaging. The coil choice for 3T imaging of the wrist depends on a number of variables, and the proper coil design selection is critical for high-resolution wrist imaging with high signal and contrast-to-noise ratio. The TFCC is a complex structure and is composed of the articular disc (disc proper), the triangular ligament, the dorsal and volar radioulnar ligaments, the meniscus homologue, the ulnar collateral ligament (UCL), the extensor carpi ulnaris (ECU) tendon sheath, and the ulnolunate and ulnotriquetral ligaments. The Palmer classification categorizes TFCC lesions as traumatic (type 1) or degenerative (type 2). In this review article, we present clinical high-resolution MR images of normal TFCC anatomy and TFCC injuries with this classification system.

Reducing radiation dose to the female breast during CT coronary angiography: A simulation study comparing breast shielding, angular tube current modulation, reduced kV, and partial angle protocols using an unknown-location signal-detectability metric

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rupcich, Franco; Gilat Schmidt, Taly; Badal, Andreu

2013-08-15

Purpose: The authors compared the performance of five protocols intended to reduce dose to the breast during computed tomography (CT) coronary angiography scans using a model observer unknown-location signal-detectability metric.Methods: The authors simulated CT images of an anthropomorphic female thorax phantom for a 120 kV reference protocol and five “dose reduction” protocols intended to reduce dose to the breast: 120 kV partial angle (posteriorly centered), 120 kV tube-current modulated (TCM), 120 kV with shielded breasts, 80 kV, and 80 kV partial angle (posteriorly centered). Two image quality tasks were investigated: the detection and localization of 4-mm, 3.25 mg/ml and 1-mm,more » 6.0 mg/ml iodine contrast signals randomly located in the heart region. For each protocol, the authors plotted the signal detectability, as quantified by the area under the exponentially transformed free response characteristic curve estimator (A-caret{sub FE}), as well as noise and contrast-to-noise ratio (CNR) versus breast and lung dose. In addition, the authors quantified each protocol's dose performance as the percent difference in dose relative to the reference protocol achieved while maintaining equivalent A-caret{sub FE}.Results: For the 4-mm signal-size task, the 80 kV full scan and 80 kV partial angle protocols decreased dose to the breast (80.5% and 85.3%, respectively) and lung (80.5% and 76.7%, respectively) with A-caret{sub FE} = 0.96, but also resulted in an approximate three-fold increase in image noise. The 120 kV partial protocol reduced dose to the breast (17.6%) at the expense of increased lung dose (25.3%). The TCM algorithm decreased dose to the breast (6.0%) and lung (10.4%). Breast shielding increased breast dose (67.8%) and lung dose (103.4%). The 80 kV and 80 kV partial protocols demonstrated greater dose reductions for the 4-mm task than for the 1-mm task, and the shielded protocol showed a larger increase in dose for the 4-mm task than for the 1-mm task. In general, the CNR curves indicate a similar relative ranking of protocol performance as the corresponding A-caret{sub FE} curves, however, the CNR metric overestimated the performance of the shielded protocol for both tasks, leading to corresponding underestimates in the relative dose increases compared to those obtained when using the A-caret{sub FE} metric.Conclusions: The 80 kV and 80 kV partial angle protocols demonstrated the greatest reduction to breast and lung dose, however, the subsequent increase in image noise may be deemed clinically unacceptable. Tube output for these protocols can be adjusted to achieve a more desirable noise level with lesser breast dose savings. Breast shielding increased breast and lung dose when maintaining equivalent A-caret{sub FE}. The results demonstrated that comparisons of dose performance depend on both the image quality metric and the specific task, and that CNR may not be a reliable metric of signal detectability.« less

OVERALL PROCEDURES PROTOCOL AND PATIENT ENROLLMENT PROTOCOL: TESTING FEASIBILITY OF 3D ULTRASOUND DATA ACQUISITION AND RELIABILITY OF DATA RETRIEVAL FROM STORED 3D IMAGES

EPA Science Inventory

The purpose of this study is to examine the feasibility of collecting, transmitting,

and analyzing 3-D ultrasound data in the context of a multi-center study of pregnant

women. The study will also examine the reliability of measurements obtained from 3-D

imag...

Identifying passivated dynamic force microscopy tips on H:Si(100)

NASA Astrophysics Data System (ADS)

Sharp, Peter; Jarvis, Sam; Woolley, Richard; Sweetman, Adam; Kantorovich, Lev; Pakes, Chris; Moriarty, Philip

2012-06-01

The chemical reactivity of the tip plays a central role in image formation in dynamic force microscopy, but in very many cases the state of the probe is a key experimental unknown. We show here that an H-terminated and thus chemically unreactive tip can be readily identified via characteristic imaging and spectroscopic (F(z)) signatures, including, in particular, contrast inversion, on hydrogen-passivated Si(100). We determine the tip apex termination by comparing site-specific difference force curves with the results of density functional theory, providing a clear protocol for the identification of chemically unreactive tips on silicon surfaces.

Quantitative magneto-optical investigation of superconductor/ferromagnet hybrid structures

NASA Astrophysics Data System (ADS)

Shaw, G.; Brisbois, J.; Pinheiro, L. B. G. L.; Müller, J.; Blanco Alvarez, S.; Devillers, T.; Dempsey, N. M.; Scheerder, J. E.; Van de Vondel, J.; Melinte, S.; Vanderbemden, P.; Motta, M.; Ortiz, W. A.; Hasselbach, K.; Kramer, R. B. G.; Silhanek, A. V.

2018-02-01

We present a detailed quantitative magneto-optical imaging study of several superconductor/ferromagnet hybrid structures, including Nb deposited on top of thermomagnetically patterned NdFeB and permalloy/niobium with erasable and tailored magnetic landscapes imprinted in the permalloy layer. The magneto-optical imaging data are complemented with and compared to scanning Hall probe microscopy measurements. Comprehensive protocols have been developed for calibrating, testing, and converting Faraday rotation data to magnetic field maps. Applied to the acquired data, they reveal the comparatively weaker magnetic response of the superconductor from the background of larger fields and field gradients generated by the magnetic layer.

Clinical experience with a high-performance ATM-connected DICOM archive for cardiology

NASA Astrophysics Data System (ADS)

Solomon, Harry P.

1997-05-01

A system to archive large image sets, such as cardiac cine runs, with near realtime response must address several functional and performance issues, including efficient use of a high performance network connection with standard protocols, an architecture which effectively integrates both short- and long-term mass storage devices, and a flexible data management policy which allows optimization of image distribution and retrieval strategies based on modality and site-specific operational use. Clinical experience with such as archive has allowed evaluation of these systems issues and refinement of a traffic model for cardiac angiography.

SU-E-I-89: Assessment of CT Radiation Dose and Image Quality for An Automated Tube Potential Selection Algorithm Using Pediatric Anthropomorphic and ACR Phantoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahmood, U; Erdi, Y; Wang, W

Purpose: To assess the impact of General Electrics automated tube potential algorithm, kV assist (kVa) on radiation dose and image quality, with an emphasis on optimizing protocols based on noise texture. Methods: Radiation dose was assessed by inserting optically stimulated luminescence dosimeters (OSLs) throughout the body of a pediatric anthropomorphic phantom (CIRS). The baseline protocol was: 120 kVp, 80 mA, 0.7s rotation time. Image quality was assessed by calculating the contrast to noise ratio (CNR) and noise power spectrum (NPS) from the ACR CT accreditation phantom. CNRs were calculated according to the steps described in ACR CT phantom testing document.more » NPS was determined by taking the 3D FFT of the uniformity section of the ACR phantom. NPS and CNR were evaluated with and without kVa and for all available adaptive iterative statistical reconstruction (ASiR) settings, ranging from 0 to 100%. Each NPS was also evaluated for its peak frequency difference (PFD) with respect to the baseline protocol. Results: For the baseline protocol, CNR was found to decrease from 0.460 ± 0.182 to 0.420 ± 0.057 when kVa was activated. When compared against the baseline protocol, the PFD at ASiR of 40% yielded a decrease in noise magnitude as realized by the increase in CNR = 0.620 ± 0.040. The liver dose decreased by 30% with kVa activation. Conclusion: Application of kVa reduces the liver dose up to 30%. However, reduction in image quality for abdominal scans occurs when using the automated tube voltage selection feature at the baseline protocol. As demonstrated by the CNR and NPS analysis, the texture and magnitude of the noise in reconstructed images at ASiR 40% was found to be the same as our baseline images. We have demonstrated that 30% dose reduction is possible when using 40% ASiR with kVa in pediatric patients.« less

Enhanced multi-protocol analysis via intelligent supervised embedding (EMPrAvISE): detecting prostate cancer on multi-parametric MRI

NASA Astrophysics Data System (ADS)

Viswanath, Satish; Bloch, B. Nicholas; Chappelow, Jonathan; Patel, Pratik; Rofsky, Neil; Lenkinski, Robert; Genega, Elizabeth; Madabhushi, Anant

2011-03-01

Currently, there is significant interest in developing methods for quantitative integration of multi-parametric (structural, functional) imaging data with the objective of building automated meta-classifiers to improve disease detection, diagnosis, and prognosis. Such techniques are required to address the differences in dimensionalities and scales of individual protocols, while deriving an integrated multi-parametric data representation which best captures all disease-pertinent information available. In this paper, we present a scheme called Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE); a powerful, generalizable framework applicable to a variety of domains for multi-parametric data representation and fusion. Our scheme utilizes an ensemble of embeddings (via dimensionality reduction, DR); thereby exploiting the variance amongst multiple uncorrelated embeddings in a manner similar to ensemble classifier schemes (e.g. Bagging, Boosting). We apply this framework to the problem of prostate cancer (CaP) detection on 12 3 Tesla pre-operative in vivo multi-parametric (T2-weighted, Dynamic Contrast Enhanced, and Diffusion-weighted) magnetic resonance imaging (MRI) studies, in turn comprising a total of 39 2D planar MR images. We first align the different imaging protocols via automated image registration, followed by quantification of image attributes from individual protocols. Multiple embeddings are generated from the resultant high-dimensional feature space which are then combined intelligently to yield a single stable solution. Our scheme is employed in conjunction with graph embedding (for DR) and probabilistic boosting trees (PBTs) to detect CaP on multi-parametric MRI. Finally, a probabilistic pairwise Markov Random Field algorithm is used to apply spatial constraints to the result of the PBT classifier, yielding a per-voxel classification of CaP presence. Per-voxel evaluation of detection results against ground truth for CaP extent on MRI (obtained by spatially registering pre-operative MRI with available whole-mount histological specimens) reveals that EMPrAvISE yields a statistically significant improvement (AUC=0.77) over classifiers constructed from individual protocols (AUC=0.62, 0.62, 0.65, for T2w, DCE, DWI respectively) as well as one trained using multi-parametric feature concatenation (AUC=0.67).

Segmentation and quantification of subcellular structures in fluorescence microscopy images using Squassh.

PubMed

Rizk, Aurélien; Paul, Grégory; Incardona, Pietro; Bugarski, Milica; Mansouri, Maysam; Niemann, Axel; Ziegler, Urs; Berger, Philipp; Sbalzarini, Ivo F

2014-03-01

Detection and quantification of fluorescently labeled molecules in subcellular compartments is a key step in the analysis of many cell biological processes. Pixel-wise colocalization analyses, however, are not always suitable, because they do not provide object-specific information, and they are vulnerable to noise and background fluorescence. Here we present a versatile protocol for a method named 'Squassh' (segmentation and quantification of subcellular shapes), which is used for detecting, delineating and quantifying subcellular structures in fluorescence microscopy images. The workflow is implemented in freely available, user-friendly software. It works on both 2D and 3D images, accounts for the microscope optics and for uneven image background, computes cell masks and provides subpixel accuracy. The Squassh software enables both colocalization and shape analyses. The protocol can be applied in batch, on desktop computers or computer clusters, and it usually requires <1 min and <5 min for 2D and 3D images, respectively. Basic computer-user skills and some experience with fluorescence microscopy are recommended to successfully use the protocol.

Magnetic Resonance of Pelvic and Gastrointestinal Emergencies.

PubMed

Wongwaisayawan, Sirote; Kaewlai, Rathachai; Dattwyler, Matthew; Abujudeh, Hani H; Singh, Ajay K

2016-05-01

Magnetic resonance (MR) imaging is gaining increased acceptance in the emergency setting despite the continued dominance of computed tomography. MR has the advantages of more precise tissue characterization, superior soft tissue contrast, and a lack of ionizing radiation. Traditional barriers to emergent MR are being overcome by streamlined imaging protocols and newer rapid-acquisition sequences. As the utilization of MR imaging in the emergency department increases, a strong working knowledge of the MR appearance of the most commonly encountered abdominopelvic pathologies is essential. In this article, MR imaging protocols and findings of acute pelvic, scrotal, and gastrointestinal pathologies are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

A fully automated non-external marker 4D-CT sorting algorithm using a serial cine scanning protocol.

PubMed

Carnes, Greg; Gaede, Stewart; Yu, Edward; Van Dyk, Jake; Battista, Jerry; Lee, Ting-Yim

2009-04-07

Current 4D-CT methods require external marker data to retrospectively sort image data and generate CT volumes. In this work we develop an automated 4D-CT sorting algorithm that performs without the aid of data collected from an external respiratory surrogate. The sorting algorithm requires an overlapping cine scan protocol. The overlapping protocol provides a spatial link between couch positions. Beginning with a starting scan position, images from the adjacent scan position (which spatial match the starting scan position) are selected by maximizing the normalized cross correlation (NCC) of the images at the overlapping slice position. The process was continued by 'daisy chaining' all couch positions using the selected images until an entire 3D volume was produced. The algorithm produced 16 phase volumes to complete a 4D-CT dataset. Additional 4D-CT datasets were also produced using external marker amplitude and phase angle sorting methods. The image quality of the volumes produced by the different methods was quantified by calculating the mean difference of the sorted overlapping slices from adjacent couch positions. The NCC sorted images showed a significant decrease in the mean difference (p < 0.01) for the five patients.

Dose reduction in whole-body computed tomography of multiple injuries (DoReMI): protocol for a prospective cohort study

PubMed Central

2014-01-01

Background Single-pass, contrast-enhanced whole body multidetector computed tomography (MDCT) emerged as the diagnostic standard for evaluating patients with major trauma. Modern iterative image algorithms showed high image quality at a much lower radiation dose in the non-trauma setting. This study aims at investigating whether the radiation dose can safely be reduced in trauma patients without compromising the diagnostic accuracy and image quality. Methods/Design Prospective observational study with two consecutive cohorts of patients. Setting: A high-volume, academic, supra-regional trauma centre in Germany. Study population: Consecutive male and female patients who 1. had been exposed to a high-velocity trauma mechanism, 2. present with clinical evidence or high suspicion of multiple trauma (predicted Injury Severity Score [ISS] ≥16) and 3. are scheduled for primary MDCT based on the decision of the trauma leader on call. Imaging protocols: In a before/after design, a consecutive series of 500 patients will undergo single-pass, whole-body 128-row multi-detector computed tomography (MDCT) with a standard, as low as possible radiation dose. This will be followed by a consecutive series of 500 patients undergoing an approved ultra-low dose MDCT protocol using an image processing algorithm. Data: Routine administrative data and electronic patient records, as well as digital images stored in a picture archiving and communications system will serve as the primary data source. The protocol was approved by the institutional review board. Main outcomes: (1) incidence of delayed diagnoses, (2) diagnostic accuracy, as correlated to the reference standard of a synopsis of all subsequent clinical, imaging, surgical and autopsy findings, (3) patients’ safety, (4) radiation exposure (e.g. effective dose), (5) subjective image quality (assessed independently radiologists and trauma surgeons on a 100-mm visual analogue scale), (6) objective image quality (e.g., contrast-to-noise ratio). Analysis: Multivariate regression will be employed to adjust and correct the findings for time and cohort effects. An exploratory interim analysis halfway after introduction of low-dose MDCT will be conducted to assess whether this protocol is clearly inferior or superior to the current standard. Discussion Although non-experimental, this study will generate first large-scale data on the utility of imaging-enhancing algorithms in whole-body MDCT for major blunt trauma. Trial registration Current Controlled Trials ISRCTN74557102. PMID:24589310

Improved compressed sensing-based cone-beam CT reconstruction using adaptive prior image constraints

NASA Astrophysics Data System (ADS)

Lee, Ho; Xing, Lei; Davidi, Ran; Li, Ruijiang; Qian, Jianguo; Lee, Rena

2012-04-01

Volumetric cone-beam CT (CBCT) images are acquired repeatedly during a course of radiation therapy and a natural question to ask is whether CBCT images obtained earlier in the process can be utilized as prior knowledge to reduce patient imaging dose in subsequent scans. The purpose of this work is to develop an adaptive prior image constrained compressed sensing (APICCS) method to solve this problem. Reconstructed images using full projections are taken on the first day of radiation therapy treatment and are used as prior images. The subsequent scans are acquired using a protocol of sparse projections. In the proposed APICCS algorithm, the prior images are utilized as an initial guess and are incorporated into the objective function in the compressed sensing (CS)-based iterative reconstruction process. Furthermore, the prior information is employed to detect any possible mismatched regions between the prior and current images for improved reconstruction. For this purpose, the prior images and the reconstructed images are classified into three anatomical regions: air, soft tissue and bone. Mismatched regions are identified by local differences of the corresponding groups in the two classified sets of images. A distance transformation is then introduced to convert the information into an adaptive voxel-dependent relaxation map. In constructing the relaxation map, the matched regions (unchanged anatomy) between the prior and current images are assigned with smaller weight values, which are translated into less influence on the CS iterative reconstruction process. On the other hand, the mismatched regions (changed anatomy) are associated with larger values and the regions are updated more by the new projection data, thus avoiding any possible adverse effects of prior images. The APICCS approach was systematically assessed by using patient data acquired under standard and low-dose protocols for qualitative and quantitative comparisons. The APICCS method provides an effective way for us to enhance the image quality at the matched regions between the prior and current images compared to the existing PICCS algorithm. Compared to the current CBCT imaging protocols, the APICCS algorithm allows an imaging dose reduction of 10-40 times due to the greatly reduced number of projections and lower x-ray tube current level coming from the low-dose protocol.

SU-E-J-207: Effect of Pulse Sequence Parameters On Geometric Distortions Induced by a Titanium Brachytherapy Applicator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shea, S; Diak, A; Surucu, M

2015-06-15

Purpose: To investigate the effect of readout bandwidth and voxel size on the appearance of distortion artifacts caused by a titanium brachytherapy applicator. Methods: An acrylic phantom was constructed to rigidly hold a MR conditional, titanium Fletcher-Suit-Delclos-style applicator set (Varian Medical Systems) for imaging on CT (Philips Brilliance) and 1.5T MRI (Siemens Magnetom Aera). Several variants of MRI parameters were tried for 2D T2-weighted turbo spin echo imaging in comparison against the standard clinical protocol with the criteria to keep relative SNR loss less than 20% and imaging time as short as possible. Two 3D sequences were also used formore » comparison with similar parameters. The applicator tandem was segmented on axial CT images (0.4×0.4×1.5mm {sup 3} resolution) and the CT images were registered to the 3D MR images in Eclipse (Varian). The applicator volume was then overlaid on all MRI sets in 3D-Slicer and distances were measured from the tandem tip to the MRI artifact edge in right/left/superior and anterior/posterior/superior directions from coronal and sagittal 2D acquisitions, respectively, or 3D data reformats. Artifact regions were also manually contoured in coronal/sagittal orientations for area measurements. Results: As would be expected, reductions in voxel size and increases in readout bandwidth reduced artifact size (average max artifact length decreased by 0.95 mm and average max area decrease by 0.27 cm{sup 2}). Interestingly, bandwidth increases yielded reductions in area (0.19 cm{sup 2}) and in distance measurements (1 mm) even with voxel increases, as compared to a standard protocol. This could be useful when high performance protocols are not feasible due to long imaging times. Conclusion: We have characterized artifacts caused by cervical brachytherapy applicator across multiple sequence parameters at 1.5T. Future work will focus on finalizing an optimal protocol that balances artifact reduction with imaging time and then testing this new protocol in patients.« less

A Data Scheduling and Management Infrastructure for the TEAM Network

NASA Astrophysics Data System (ADS)

Andelman, S.; Baru, C.; Chandra, S.; Fegraus, E.; Lin, K.; Unwin, R.

2009-04-01

The objective of the Tropical Ecology Assessment and Monitoring Network (www.teamnetwork.org) is "To generate real time data for monitoring long-term trends in tropical biodiversity through a global network of TEAM sites (i.e. field stations in tropical forests), providing an early warning system on the status of biodiversity to effectively guide conservation action". To achieve this, the TEAM Network operates by collecting data via standardized protocols at TEAM Sites. The standardized TEAM protocols include the Climate, Vegetation and Terrestrial Vertebrate Protocols. Some sites also implement additional protocols. There are currently 7 TEAM Sites with plans to grow the network to 15 by June 30, 2009 and 50 TEAM Sites by the end of 2010. Climate Protocol The Climate Protocol entails the collection of climate data via meteorological stations located at the TEAM Sites. This includes information such as precipitation, temperature, wind direction and strength and various solar radiation measurements. Vegetation Protocol The Vegetation Protocol collects standardized information on tropical forest trees and lianas. A TEAM Site will have between 6-9 1ha plots where trees and lianas larger than a pre-specified size are mapped, identified and measured. This results in each TEAM Site repeatedly measuring between 3000-5000 trees annually. Terrestrial Vertebrate Protocol The Terrestrial Vertebrate Protocol collects standardized information on mid-sized tropical forest fauna (i.e. birds and mammals). This information is collected via camera traps (i.e. digital cameras with motion sensors housed in weather proof casings). The images taken by the camera trap are reviewed to identify what species are captured in the image by the camera trap. The image and the interpretation of what is in the image are the data for the Terrestrial Vertebrate Protocol. The amount of data collected through the TEAM protocols provides a significant yet exciting IT challenge. The TEAM Network is currently partnering with the San Diego Super Computer Center to build the data management infrastructure. Data collected from the three core protocols as well as others are currently made available through the TEAM Network portal, which provides the content management framework, the data scheduling and management framework, an administrative framework to implement and manage TEAM sites, collaborative tools and a number of tools and applications utilizing Google Map and Google Earth products. A critical element of the TEAM Network data management infrastructure is to make the data publicly available in as close to real-time as possible (the TEAM Network Data Use Policy: http://www.teamnetwork.org/en/data/policy). This requires two essential tasks to be accomplished, 1) A data collection schedule has to be planned, proposed and approved for a given TEAM site. This is a challenging process since TEAM sites are geographically distributed across the tropics and hence have different seasons where they schedule field sampling for the different TEAM protocols. Capturing this information and ensuring that TEAM sites follow the outlined legal contract is key to the data collection process and 2) A stream-lined and efficient information management system to ensure data collected from the field meet the minimum data standards (i.e. are of the highest scientific quality) and are securely transferred, archived, processed and be rapidly made publicaly available, as a finished consumable product via the TEAM Network portal. The TEAM Network is achieving these goals by implementing an end-to-end framework consisting of the Sampling Scheduler application and the Data Management Framework. Sampling Scheduler The Sampling Scheduler is a project management, calendar based portal application that will allow scientists at a TEAM site to schedule field sampling for each of the TEAM protocols implemented at that site. The sampling scheduler addresses the specific requirements established in the TEAM protocols with the logistical scheduling needs of each TEAM Site. For example, each TEAM protocol defines when data must be collected (e.g. time of day, number of times per year, during which seasons, etc) as well as where data must be collected (from which sampling units, which trees, etc). Each TEAM Site has a limited number of resources and must create plans that will both satisfy the requirements of the protocols as well as be logistically feasible for their TEAM Site. With 15 TEAM Sites (and many more coming soon) the schedules of each TEAM Site must be communicated to the Network Office to ensure data are being collected as scheduled and to address the many problems when working in difficult environments like Tropical Forests. The Sampling Schedule provides built-in proposal and approval functionality to ensure that the TEAM Sites are and the Network office are in sync as well as provides the capability to modify schedules when needed. The Data Management Framework The Data Management framework is a three-tier data ingestion, edit and review application for protocols defined in the TEAM network. The data ingestion framework provides online web forms for field personnel to submit and edit data collected at TEAM Sites. These web forms will be accessible from the TEAM content management site. Once the data is securely uploaded, cured, processed and approved, it will be made publicly available for consumption by the scientific community. The Data Management framework, when combined with the Sampling Scheduler provides a closed loop Data Scheduling and Management infrastructure. All information starting from data collection plan, tools to input, modify and curate data, review and run QA/QC tests, as well as verify data are collected as planed are included. Finally, TEAM Network data are available for download via the Data Query and Download Application. This application utilizes a Google Maps custom interface to search, visualize, and download TEAM Network data. References • TEAM Network, http://www.teamnetwork.org • Center for Applied Biodiversity Science, Conservation International. http://science.conservation.org/portal/server.pt • TEAM Data Query and Download Application, http://www.teamnetwork.org/en/data/query

Feasibility of an intracranial EEG-fMRI protocol at 3T: risk assessment and image quality.

PubMed

Boucousis, Shannon M; Beers, Craig A; Cunningham, Cameron J B; Gaxiola-Valdez, Ismael; Pittman, Daniel J; Goodyear, Bradley G; Federico, Paolo

2012-11-15

Integrating intracranial EEG (iEEG) with functional MRI (iEEG-fMRI) may help elucidate mechanisms underlying the generation of seizures. However, the introduction of iEEG electrodes in the MR environment has inherent risk and data quality implications that require consideration prior to clinical use. Previous studies of subdural and depth electrodes have confirmed low risk under specific circumstances at 1.5T and 3T. However, no studies have assessed risk and image quality related to the feasibility of a full iEEG-fMRI protocol. To this end, commercially available platinum subdural grid/strip electrodes (4×5 grid or 1×8 strip) and 4 or 6-contact depth electrodes were secured to the surface of a custom-made phantom mimicking the conductivity of the human brain. Electrode displacement, temperature increase of electrodes and surrounding phantom material, and voltage fluctuations in electrode contacts were measured in a GE Discovery MR750 3T MR scanner during a variety of imaging sequences, typical of an iEEG-fMRI protocol. An electrode grid was also used to quantify the spatial extent of susceptibility artifact. The spatial extent of susceptibility artifact in the presence of an electrode was also assessed for typical imaging parameters that maximize BOLD sensitivity at 3T (TR=1500 ms; TE=30 ms; slice thickness=4mm; matrix=64×64; field-of-view=24 cm). Under standard conditions, all electrodes exhibited no measurable displacement and no clinically significant temperature increase (<1°C) during scans employed in a typical iEEG-fMRI experiment, including 60 min of continuous fMRI. However, high SAR sequences, such as fast spin-echo (FSE), produced significant heating in almost all scenarios (>2.0°C) that in some cases exceeded 10°C. Induced voltages in the frequency range that could elicit neuronal stimulation (<10 kHz) were well below the threshold of 100 mV. fMRI signal intensity was significantly reduced within 20mm of the electrodes for the imaging parameters used in this study. Thus, for the conditions tested, a full iEEG-fMRI protocol poses a low risk at 3T; however, fMRI sensitivity may be reduced immediately adjacent to the electrodes. In addition, high SAR sequences must be avoided. Copyright © 2012 Elsevier Inc. All rights reserved.

Organ dose measurements from multiple-detector computed tomography using a commercial dosimetry system and tomographic, physical phantoms

NASA Astrophysics Data System (ADS)

Lavoie, Lindsey K.

The technology of computed tomography (CT) imaging has soared over the last decade with the use of multi-detector CT (MDCT) scanners that are capable of performing studies in a matter of seconds. While the diagnostic information obtained from MDCT imaging is extremely valuable, it is important to ensure that the radiation doses resulting from these studies are at acceptably safe levels. This research project focused on the measurement of organ doses resulting from modern MDCT scanners. A commercially-available dosimetry system was used to measure organ doses. Small dosimeters made of optically-stimulated luminescent (OSL) material were analyzed with a portable OSL reader. Detailed verification of this system was performed. Characteristics studied include energy, scatter, and angular responses; dose linearity, ability to erase the exposed dose and ability to reuse dosimeters multiple times. The results of this verification process were positive. While small correction factors needed to be applied to the dose reported by the OSL reader, these factors were small and expected. Physical, tomographic pediatric and adult phantoms were used to measure organ doses. These phantoms were developed from CT images and are composed of tissue-equivalent materials. Because the adult phantom is comprised of numerous segments, dosimeters were placed in the phantom at several organ locations, and doses to select organs were measured using three clinical protocols: pediatric craniosynostosis, adult brain perfusion and adult cardiac CT angiography (CTA). A wide-beam, 320-slice, volumetric CT scanner and a 64-slice, MDCT scanner were used for organ dose measurements. Doses ranged from 1 to 26 mGy for the pediatric protocol, 1 to 1241 mGy for the brain perfusion protocol, and 2-100 mGy for the cardiac protocol. In most cases, the doses measured on the 64-slice scanner were higher than those on the 320-slice scanner. A methodology to measure organ doses with OSL dosimeters received from CT imaging has been presented. These measurements are especially important in keeping with the ALARA (as low as reasonably achievable) principle. While diagnostic information from CT imaging is valuable and necessary, the dose to patients is always a consideration. This methodology aids in this important task. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Demystifying MR Neurography of the Lumbosacral Plexus: From Protocols to Pathologies

PubMed Central

Muniz Neto, Francisco J.; Kihara Filho, Eduardo N.; Miranda, Frederico C.; Rosemberg, Laercio A.; Santos, Durval C. B.

2018-01-01

Magnetic resonance neurography is a high-resolution imaging technique that allows evaluating different neurological pathologies in correlation to clinical and the electrophysiological data. The aim of this article is to present a review on the anatomy of the lumbosacral plexus nerves, along with imaging protocols, interpretation pitfalls, and most common pathologies that should be recognized by the radiologist: traumatic, iatrogenic, entrapment, tumoral, infectious, and inflammatory conditions. An extensive series of clinical and imaging cases is presented to illustrate key-points throughout the article. PMID:29662907

TU-A-201-02: Treatment Site-Specific Considerations for Clinical IGRT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wijesooriya, K.

2016-06-15

Recent years have seen a widespread proliferation of available in-room image guidance systems for radiation therapy target localization with many centers having multiple in-room options. In this session, available imaging systems for in-room IGRT will be reviewed highlighting the main differences in workflow efficiency, targeting accuracy and image quality as it relates to target visualization. Decision-making strategies for integrating these tools into clinical image guidance protocols that are tailored to specific disease sites like H&N, lung, pelvis, and spine SBRT will be discussed. Learning Objectives: Major system characteristics of a wide range of available in-room imaging systems for IGRT. Advantagesmore » / disadvantages of different systems for site-specific IGRT considerations. Concepts of targeting accuracy and time efficiency in designing clinical imaging protocols.« less

Brachial plexus assessment with three-dimensional isotropic resolution fast spin echo MRI: comparison with conventional MRI at 3.0 T

PubMed Central

Tagliafico, A; Succio, G; Neumaier, C E; Baio, G; Serafini, G; Ghidara, M; Calabrese, M; Martinoli, C

2012-01-01

Objective The purpose of our study was to determine whether a three-dimensional (3D) isotropic resolution fast spin echo sequence (FSE-cube) has similar image quality and diagnostic performance to a routine MRI protocol for brachial plexus evaluation in volunteers and symptomatic patients at 3.0 T. Institutional review board approval and written informed consent were guaranteed. Methods In this prospective study FSE-cube was added to the standard brachial plexus examination protocol in eight patients (mean age, 50.2 years) with brachial plexus pathologies and in six volunteers (mean age, 54 years). Nerve visibility, tissue contrast, edge sharpness, image blurring, motion artefact and acquisition time were calculated for FSE-cube sequences and for the standard protocol on a standardised five-point scale. The visibility of brachial plexus nerve and surrounding tissues at four levels (roots, interscalene area, costoclavicular space and axillary level) was assessed. Results Image quality and nerve visibility did not significantly differ between FSE-cube and the standard protocol (p>0.05). Acquisition time was statistically and clinically significantly shorter with FSE-cube (p<0.05). Pathological findings were seen equally well with FSE-cube and the standard protocol. Conclusion 3D FSE-cube provided similar image quality in a shorter acquisition time and enabled excellent visualisation of brachial plexus anatomy and pathology in any orientation, regardless of the original scanning plane. PMID:21343321

Development of a Multileaf Collimator for Proton Radiotherapy

DTIC Science & Technology

2007-06-01

for proton radiotherapy, and the first year of the project to develop image guided treatment protocols for proton therapy . This research...multileaf collimator (MLC) for proton therapy and investigates the issues that must be resolved to use an MLC in proton therapy . The second technology...the contract included three development agreements directly related to the work supported by this grant to develop technology for proton therapy .

Narrow band imaging combined with water immersion technique in the diagnosis of celiac disease.

PubMed

Valitutti, Francesco; Oliva, Salvatore; Iorfida, Donatella; Aloi, Marina; Gatti, Silvia; Trovato, Chiara Maria; Montuori, Monica; Tiberti, Antonio; Cucchiara, Salvatore; Di Nardo, Giovanni

2014-12-01

The "multiple-biopsy" approach both in duodenum and bulb is the best strategy to confirm the diagnosis of celiac disease; however, this increases the invasiveness of the procedure itself and is time-consuming. To evaluate the diagnostic yield of a single biopsy guided by narrow-band imaging combined with water immersion technique in paediatric patients. Prospective assessment of the diagnostic accuracy of narrow-band imaging/water immersion technique-driven biopsy approach versus standard protocol in suspected celiac disease. The experimental approach correctly diagnosed 35/40 children with celiac disease, with an overall diagnostic sensitivity of 87.5% (95% CI: 77.3-97.7). An altered pattern of narrow-band imaging/water immersion technique endoscopic visualization was significantly associated with villous atrophy at guided biopsy (Spearman Rho 0.637, p<0.001). Concordance of narrow-band imaging/water immersion technique endoscopic assessments was high between two operators (K: 0.884). The experimental protocol was highly timesaving compared to the standard protocol. An altered narrow-band imaging/water immersion technique pattern coupled with high anti-transglutaminase antibodies could allow a single guided biopsy to diagnose celiac disease. When no altered mucosal pattern is visible even by narrow-band imaging/water immersion technique, multiple bulbar and duodenal biopsies should be obtained. Copyright © 2014. Published by Elsevier Ltd.

The Influence of a Dietary Protocol on Cone Beam CT-Guided Radiotherapy for Prostate Cancer Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smitsmans, Monique H.P.; Pos, Floris J.; Bois, Josien de

2008-07-15

Purpose: To evaluate the influence of a dietary protocol on cone beam computed tomography (CBCT) image quality, which is an indirect indicator for short-term (intrafraction) prostate motion, and on interfraction motion. Image quality is affected by motion (e.g., moving gas) during imaging and influences the performance of automatic prostate localization on CBCT scans. Methods and Materials: Twenty-six patients (336 CBCT scans) followed the dietary protocol and 23 patients (240 CBCT scans) did not. Prostates were automatically localized by using three dimensional (3D) gray-value registration (GR). Feces and (moving) gas occurrence in the CBCT scans, the success rate of 3D-GR, andmore » the statistics of prostate motion data were assessed. Results: Feces, gas, and moving gas significantly decreased from 55%, 61%, and 43% of scans in the nondiet group to 31%, 47%, and 28% in the diet group (all p < 0.001). Since there is a known relation between gas and short-term prostate motion, intrafraction prostate motion probably also decreased. The success rate of 3D-GR improved from 83% to 94% (p < 0.001). A decrease in random interfraction prostate motion also was found, which was not significant after Bonferroni's correction. Significant deviations from planning CT position for rotations around the left-right axis were found in both groups. Conclusions: The dietary protocol significantly decreased the incidence of feces and (moving) gas. As a result, CBCT image quality and the success rate of 3D-GR significantly increased. A trend exists that random interfraction prostate motion decreases. Using a dietary protocol therefore is advisable, also without CBCT-based image guidance.« less

Quantitative image feature variability amongst CT scanners with a controlled scan protocol

NASA Astrophysics Data System (ADS)

Ger, Rachel B.; Zhou, Shouhao; Chi, Pai-Chun Melinda; Goff, David L.; Zhang, Lifei; Lee, Hannah J.; Fuller, Clifton D.; Howell, Rebecca M.; Li, Heng; Stafford, R. Jason; Court, Laurence E.; Mackin, Dennis S.

2018-02-01

Radiomics studies often analyze patient computed tomography (CT) images acquired from different CT scanners. This may result in differences in imaging parameters, e.g. different manufacturers, different acquisition protocols, etc. However, quantifiable differences in radiomics features can occur based on acquisition parameters. A controlled protocol may allow for minimization of these effects, thus allowing for larger patient cohorts from many different CT scanners. In order to test radiomics feature variability across different CT scanners a radiomics phantom was developed with six different cartridges encased in high density polystyrene. A harmonized protocol was developed to control for tube voltage, tube current, scan type, pitch, CTDIvol, convolution kernel, display field of view, and slice thickness across different manufacturers. The radiomics phantom was imaged on 18 scanners using the control protocol. A linear mixed effects model was created to assess the impact of inter-scanner variability with decomposition of feature variation between scanners and cartridge materials. The inter-scanner variability was compared to the residual variability (the unexplained variability) and to the inter-patient variability using two different patient cohorts. The patient cohorts consisted of 20 non-small cell lung cancer (NSCLC) and 30 head and neck squamous cell carcinoma (HNSCC) patients. The inter-scanner standard deviation was at least half of the residual standard deviation for 36 of 49 quantitative image features. The ratio of inter-scanner to patient coefficient of variation was above 0.2 for 22 and 28 of the 49 features for NSCLC and HNSCC patients, respectively. Inter-scanner variability was a significant factor compared to patient variation in this small study for many of the features. Further analysis with a larger cohort will allow more thorough analysis with additional variables in the model to truly isolate the interscanner difference.

Histology image analysis for carcinoma detection and grading

PubMed Central

He, Lei; Long, L. Rodney; Antani, Sameer; Thoma, George R.

2012-01-01

This paper presents an overview of the image analysis techniques in the domain of histopathology, specifically, for the objective of automated carcinoma detection and classification. As in other biomedical imaging areas such as radiology, many computer assisted diagnosis (CAD) systems have been implemented to aid histopathologists and clinicians in cancer diagnosis and research, which have been attempted to significantly reduce the labor and subjectivity of traditional manual intervention with histology images. The task of automated histology image analysis is usually not simple due to the unique characteristics of histology imaging, including the variability in image preparation techniques, clinical interpretation protocols, and the complex structures and very large size of the images themselves. In this paper we discuss those characteristics, provide relevant background information about slide preparation and interpretation, and review the application of digital image processing techniques to the field of histology image analysis. In particular, emphasis is given to state-of-the-art image segmentation methods for feature extraction and disease classification. Four major carcinomas of cervix, prostate, breast, and lung are selected to illustrate the functions and capabilities of existing CAD systems. PMID:22436890

A Study on the Basic Criteria for Selecting Heterogeneity Parameters of F18-FDG PET Images.

PubMed

Forgacs, Attila; Pall Jonsson, Hermann; Dahlbom, Magnus; Daver, Freddie; D DiFranco, Matthew; Opposits, Gabor; K Krizsan, Aron; Garai, Ildiko; Czernin, Johannes; Varga, Jozsef; Tron, Lajos; Balkay, Laszlo

2016-01-01

Textural analysis might give new insights into the quantitative characterization of metabolically active tumors. More than thirty textural parameters have been investigated in former F18-FDG studies already. The purpose of the paper is to declare basic requirements as a selection strategy to identify the most appropriate heterogeneity parameters to measure textural features. Our predefined requirements were: a reliable heterogeneity parameter has to be volume independent, reproducible, and suitable for expressing quantitatively the degree of heterogeneity. Based on this criteria, we compared various suggested measures of homogeneity. A homogeneous cylindrical phantom was measured on three different PET/CT scanners using the commonly used protocol. In addition, a custom-made inhomogeneous tumor insert placed into the NEMA image quality phantom was imaged with a set of acquisition times and several different reconstruction protocols. PET data of 65 patients with proven lung lesions were retrospectively analyzed as well. Four heterogeneity parameters out of 27 were found as the most attractive ones to characterize the textural properties of metabolically active tumors in FDG PET images. These four parameters included Entropy, Contrast, Correlation, and Coefficient of Variation. These parameters were independent of delineated tumor volume (bigger than 25-30 ml), provided reproducible values (relative standard deviation< 10%), and showed high sensitivity to changes in heterogeneity. Phantom measurements are a viable way to test the reliability of heterogeneity parameters that would be of interest to nuclear imaging clinicians.

The effect of different methods and image analyzers on the results of the in vivo comet assay.

PubMed

Kyoya, Takahiro; Iwamoto, Rika; Shimanura, Yuko; Terada, Megumi; Masuda, Shuichi

2018-01-01

The in vivo comet assay is a widely used genotoxicity test that can detect DNA damage in a range of organs. It is included in the Organisation for Economic Co-operation and Development Guidelines for the Testing of Chemicals. However, various protocols are still used for this assay, and several different image analyzers are used routinely to evaluate the results. Here, we verified a protocol that largely contributes to the equivalence of results, and we assessed the effect on the results when slides made from the same sample were analyzed using two different image analyzers (Comet Assay IV vs Comet Analyzer). Standardizing the agarose concentrations and DNA unwinding and electrophoresis times had a large impact on the equivalence of the results between the different methods used for the in vivo comet assay. In addition, there was some variation in the sensitivity of the two different image analyzers tested; however this variation was considered to be minor and became negligible when the test conditions were standardized between the two different methods. By standardizing the concentrations of low melting agarose and DNA unwinding and electrophoresis times between both methods used in the current study, the sensitivity to detect the genotoxicity of a positive control substance in the in vivo comet assay became generally comparable, independently of the image analyzer used. However, there may still be the possibility that other conditions, except for the three described here, could affect the reproducibility of the in vivo comet assay.

A Study on the Basic Criteria for Selecting Heterogeneity Parameters of F18-FDG PET Images

PubMed Central

Forgacs, Attila; Pall Jonsson, Hermann; Dahlbom, Magnus; Daver, Freddie; D. DiFranco, Matthew; Opposits, Gabor; K. Krizsan, Aron; Garai, Ildiko; Czernin, Johannes; Varga, Jozsef; Tron, Lajos; Balkay, Laszlo

2016-01-01

Textural analysis might give new insights into the quantitative characterization of metabolically active tumors. More than thirty textural parameters have been investigated in former F18-FDG studies already. The purpose of the paper is to declare basic requirements as a selection strategy to identify the most appropriate heterogeneity parameters to measure textural features. Our predefined requirements were: a reliable heterogeneity parameter has to be volume independent, reproducible, and suitable for expressing quantitatively the degree of heterogeneity. Based on this criteria, we compared various suggested measures of homogeneity. A homogeneous cylindrical phantom was measured on three different PET/CT scanners using the commonly used protocol. In addition, a custom-made inhomogeneous tumor insert placed into the NEMA image quality phantom was imaged with a set of acquisition times and several different reconstruction protocols. PET data of 65 patients with proven lung lesions were retrospectively analyzed as well. Four heterogeneity parameters out of 27 were found as the most attractive ones to characterize the textural properties of metabolically active tumors in FDG PET images. These four parameters included Entropy, Contrast, Correlation, and Coefficient of Variation. These parameters were independent of delineated tumor volume (bigger than 25–30 ml), provided reproducible values (relative standard deviation< 10%), and showed high sensitivity to changes in heterogeneity. Phantom measurements are a viable way to test the reliability of heterogeneity parameters that would be of interest to nuclear imaging clinicians. PMID:27736888

In vivo imaging of the dynamics of different variants of EGFR in glioblastomas.

PubMed

Shah, Khalid

2011-01-01

A number of altered pathways in cancer cells depend on growth factor receptors. The amplification/alteration of the epidermal growth factor receptor (EGFR) has been shown to play a significant role in enhancing tumor burden in a number of tumors, including malignant glioblastomas (GBM). To dissect the role of EGFR expression in tumor progression in mouse models of cancer and ultimately evaluate targeted therapies, it is necessary to visualize the dynamics of EGFR in real time in vivo. Non-invasive imaging based on quantitative and qualitative changes in light emission by fluorescent and bioluminescent markers offers a huge potential to facilitate drug development. Multiple approaches could be used to follow a molecular target or pathway with the fusion of a bioluminescent-fluorescent marker. This unit describes a protocol for simultaneously imaging EGFR activity and progression of GBM in a mouse model. Human glioma cells transduced with lentiviral vectors bearing different combinations of fluorescent and bioluminescent proteins either fused to EGFR or expressed alone can be grown as monolayers and maintained over several passages. The unit begins with a method for transducing glioma cells with lentiviral vectors for stable expression of these fluorescent and bioluminescent markers in vitro, followed by transplantation of engineered glioma cells in mice, and, finally, sequential bioluminescent imaging of EGFR expression and GBM progression in mice. The protocol details characterization of engineered glioma cells in culture, surgical preparation, craniotomy, cell implantation, animal recovery, and imaging procedures to study kinetics of EGFR expression and GBM progression.

Run-length encoding graphic rules, biochemically editable designs and steganographical numeric data embedment for DNA-based cryptographical coding system.

PubMed

Kawano, Tomonori

2013-03-01

There have been a wide variety of approaches for handling the pieces of DNA as the "unplugged" tools for digital information storage and processing, including a series of studies applied to the security-related area, such as DNA-based digital barcodes, water marks and cryptography. In the present article, novel designs of artificial genes as the media for storing the digitally compressed data for images are proposed for bio-computing purpose while natural genes principally encode for proteins. Furthermore, the proposed system allows cryptographical application of DNA through biochemically editable designs with capacity for steganographical numeric data embedment. As a model case of image-coding DNA technique application, numerically and biochemically combined protocols are employed for ciphering the given "passwords" and/or secret numbers using DNA sequences. The "passwords" of interest were decomposed into single letters and translated into the font image coded on the separate DNA chains with both the coding regions in which the images are encoded based on the novel run-length encoding rule, and the non-coding regions designed for biochemical editing and the remodeling processes revealing the hidden orientation of letters composing the original "passwords." The latter processes require the molecular biological tools for digestion and ligation of the fragmented DNA molecules targeting at the polymerase chain reaction-engineered termini of the chains. Lastly, additional protocols for steganographical overwriting of the numeric data of interests over the image-coding DNA are also discussed.

Dosimetry applications in GATE Monte Carlo toolkit.

PubMed

Papadimitroulas, Panagiotis

2017-09-01

Monte Carlo (MC) simulations are a well-established method for studying physical processes in medical physics. The purpose of this review is to present GATE dosimetry applications on diagnostic and therapeutic simulated protocols. There is a significant need for accurate quantification of the absorbed dose in several specific applications such as preclinical and pediatric studies. GATE is an open-source MC toolkit for simulating imaging, radiotherapy (RT) and dosimetry applications in a user-friendly environment, which is well validated and widely accepted by the scientific community. In RT applications, during treatment planning, it is essential to accurately assess the deposited energy and the absorbed dose per tissue/organ of interest, as well as the local statistical uncertainty. Several types of realistic dosimetric applications are described including: molecular imaging, radio-immunotherapy, radiotherapy and brachytherapy. GATE has been efficiently used in several applications, such as Dose Point Kernels, S-values, Brachytherapy parameters, and has been compared against various MC codes which are considered as standard tools for decades. Furthermore, the presented studies show reliable modeling of particle beams when comparing experimental with simulated data. Examples of different dosimetric protocols are reported for individualized dosimetry and simulations combining imaging and therapy dose monitoring, with the use of modern computational phantoms. Personalization of medical protocols can be achieved by combining GATE MC simulations with anthropomorphic computational models and clinical anatomical data. This is a review study, covering several dosimetric applications of GATE, and the different tools used for modeling realistic clinical acquisitions with accurate dose assessment. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turley, Jessica; Claridge Mackonis, Elizabeth

To evaluate in-field megavoltage (MV) imaging of simultaneously integrated boost (SIB) breast fields to determine its feasibility in treatment verification for the SIB breast radiotherapy technique, and to assess whether the current-imaging protocol and treatment margins are sufficient. For nine patients undergoing SIB breast radiotherapy, in-field MV images of the SIB fields were acquired on days that regular treatment verification imaging was performed. The in-field images were matched offline according to the scar wire on digitally reconstructed radiographs. The offline image correction results were then applied to a margin recipe formula to calculate safe margins that account for random andmore » systematic uncertainties in the position of the boost volume when an offline correction protocol has been applied. After offline assessment of the acquired images, 96% were within the tolerance set in the current department-imaging protocol. Retrospectively performing the maximum position deviations on the Eclipse™ treatment planning system demonstrated that the clinical target volume (CTV) boost received a minimum dose difference of 0.4% and a maximum dose difference of 1.4% less than planned. Furthermore, applying our results to the Van Herk margin formula to ensure that 90% of patients receive 95% of the prescribed dose, the calculated CTV margins were comparable to the current departmental procedure used. Based on the in-field boost images acquired and the feasible application of these results to the margin formula the current CTV-planning target volume margins used are appropriate for the accurate treatment of the SIB boost volume without additional imaging.« less

Quantitative analysis of phosphoinositide 3-kinase (PI3K) signaling using live-cell total internal reflection fluorescence (TIRF) microscopy.

PubMed

Johnson, Heath E; Haugh, Jason M

2013-12-02

This unit focuses on the use of total internal reflection fluorescence (TIRF) microscopy and image analysis methods to study the dynamics of signal transduction mediated by class I phosphoinositide 3-kinases (PI3Ks) in mammalian cells. The first four protocols cover live-cell imaging experiments, image acquisition parameters, and basic image processing and segmentation. These methods are generally applicable to live-cell TIRF experiments. The remaining protocols outline more advanced image analysis methods, which were developed in our laboratory for the purpose of characterizing the spatiotemporal dynamics of PI3K signaling. These methods may be extended to analyze other cellular processes monitored using fluorescent biosensors. Copyright © 2013 John Wiley & Sons, Inc.

Advances in cardiac CT contrast injection and acquisition protocols.

PubMed

Scholtz, Jan-Erik; Ghoshhajra, Brian

2017-10-01

Cardiac computed tomography (CT) imaging has become an important part of modern cardiovascular care. Coronary CT angiography (CTA) is the first choice imaging modality for non-invasive visualization of coronary artery stenosis. In addition, cardiac CT does not only provide anatomical evaluation, but also functional and valvular assessment, and myocardial perfusion evaluation. In this article we outline the factors which influence contrast enhancement, give an overview of current contrast injection and acquisition protocols, with focus on current emerging topics such as pre-transcatheter aortic valve replacement (TAVR) planning, cardiac CT for congenital heart disease (CHD) patients, and myocardial CT perfusion (CTP). Further, we point out areas where we see potential for future improvements in cardiac CT imaging based on a closer interaction between CT scanner settings and contrast injection protocols to tailor injections to patient- and exam-specific factors.

Advances in cardiac CT contrast injection and acquisition protocols

PubMed Central

Scholtz, Jan-Erik

2017-01-01

Cardiac computed tomography (CT) imaging has become an important part of modern cardiovascular care. Coronary CT angiography (CTA) is the first choice imaging modality for non-invasive visualization of coronary artery stenosis. In addition, cardiac CT does not only provide anatomical evaluation, but also functional and valvular assessment, and myocardial perfusion evaluation. In this article we outline the factors which influence contrast enhancement, give an overview of current contrast injection and acquisition protocols, with focus on current emerging topics such as pre-transcatheter aortic valve replacement (TAVR) planning, cardiac CT for congenital heart disease (CHD) patients, and myocardial CT perfusion (CTP). Further, we point out areas where we see potential for future improvements in cardiac CT imaging based on a closer interaction between CT scanner settings and contrast injection protocols to tailor injections to patient- and exam-specific factors. PMID:29255688

Facilitated versus self-guided training of non-ophthalmologists for grading pre-plus and plus disease using fundus images for retinopathy of prematurity screening

PubMed Central

Raufi, Nikolas N.; Morris, Caleb K.; Freedman, Sharon F.; Wallace, David K.; Prakalapakorn, S. Grace

2016-01-01

Purpose Retinopathy of prematurity (ROP) is an important cause of preventable blindness; barriers to screening necessitate novel approaches. While trained non-ophthalmologists can accurately grade retinal images for ROP, effective training protocols are not established. This study compares the effectiveness of facilitated versus self-guided training of non-ophthalmologists for grading retinal images for pre-plus or plus disease in ROP. Methods Forty-eight undergraduate and graduate students were trained to grade retinal images for the presence of pre-plus or plus disease. Students were randomly assigned to one of two training protocols. Both utilized identical electronic slideshows; one guided by an in-person facilitator, and the other was self-guided. After completing their respective training, students proficient in grading pre-plus and plus disease graded images in a telemedicine screening scenario. Accuracy of grading was compared to the reference standard of clinical examination. Results 83% (40/48) of trained students (91% in the facilitated vs. 77% in the self-guided group, p=0.26) were proficient and qualified to grade the ROP telemedicine screening scenario. Median accuracy for grading normal, pre-plus or plus disease was 69% (70% in the facilitated vs. 68% in the self-guided group, p=0.91). When considering the designation of pre-plus or plus disease by graders as a screening test for detecting plus disease (confirmed on clinical exam), the median sensitivity and specificity of all students was 95% and 64%, respectively. Conclusions Both facilitated- and self-guided teaching protocols yielded similar performance in ROP image grading for pre-plus or plus disease. Self-guided training protocols may be adequate to train non-ophthalmologists to grade retinal images for pre-plus and plus disease with high sensitivity. PMID:27224953

The remote diagnosis of malaria using telemedicine or e-mailed images.

PubMed

Murray, Clinton K; Mody, Rupal M; Dooley, David P; Hospenthal, Duane R; Horvath, Lynn L; Moran, Kimberly A; Muntz, Ronald W

2006-12-01

We determined the ability of blinded remote expert microscopy to identify malaria parasites through transmission of malaria smear images via telemedicine and as e-mail attachments. Protocols for malaria smear transmission included: (1) transmission of sender-selected televised smears at various bandwidths (Bw), (2) transmission of remote reader-directed televised smears at various Bw, and (3) transmission of digital photomicrographs as e-mail attachments. Twenty (14%) of 147 sender-selected, and 13 (6%) of 221 reader-directed, images were deemed unreadable by slide readers. The presence or absence of malaria was correctly identified in 98% of the remaining images. Sixty-four (34%) of 190 digital microphotographs were deemed unreadable, while the presence or absence of malaria was correctly identified in 100% of the remaining images. Correct speciation ranged from 45% to 83% across various transmission methods and Bw. The use of telemedicine and e-mail technology shows promise for the remote diagnosis of malaria.

SU-F-R-40: Robustness Test of Computed Tomography Textures of Lung Tissues to Varying Scanning Protocols Using a Realistic Phantom Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S; Markel, D; Hegyi, G

2016-06-15

Purpose: The reliability of computed tomography (CT) textures is an important element of radiomics analysis. This study investigates the dependency of lung CT textures on different breathing phases and changes in CT image acquisition protocols in a realistic phantom setting. Methods: We investigated 11 CT texture features for radiation-induced lung disease from 3 categories (first-order, grey level co-ocurrence matrix (GLCM), and Law’s filter). A biomechanical swine lung phantom was scanned at two breathing phases (inhale/exhale) and two scanning protocols set for PET/CT and diagnostic CT scanning. Lung volumes acquired from the CT images were divided into 2-dimensional sub-regions with amore » grid spacing of 31 mm. The distribution of the evaluated texture features from these sub-regions were compared between the two scanning protocols and two breathing phases. The significance of each factor on feature values were tested at 95% significance level using analysis of covariance (ANCOVA) model with interaction terms included. Robustness of a feature to a scanning factor was defined as non-significant dependence on the factor. Results: Three GLCM textures (variance, sum entropy, difference entropy) were robust to breathing changes. Two GLCM (variance, sum entropy) and 3 Law’s filter textures (S5L5, E5L5, W5L5) were robust to scanner changes. Moreover, the two GLCM textures (variance, sum entropy) were consistent across all 4 scanning conditions. First-order features, especially Hounsfield unit intensity features, presented the most drastic variation up to 39%. Conclusion: Amongst the studied features, GLCM and Law’s filter texture features were more robust than first-order features. However, the majority of the features were modified by either breathing phase or scanner changes, suggesting a need for calibration when retrospectively comparing scans obtained at different conditions. Further investigation is necessary to identify the sensitivity of individual image acquisition parameters.« less

Application of EARL (ResEARch 4 Life®) protocols for [18F]FDG-PET/CT clinical and research studies. A roadmap towards exact recovery coefficient

NASA Astrophysics Data System (ADS)

Balcerzyk, Marcin; Fernández-López, Rosa; Parrado-Gallego, Ángel; Pachón-Garrudo, Víctor Manuel; Chavero-Royan, José; Hevilla, Juan; Jiménez-Ortega, Elisa; Leal, Antonio

2017-11-01

Tumour uptake value is a critical result in [18F]FDG-PET/CT ([18F]fluorodeoxyglucose) quantitative scans such as the dose prescription for radiotherapy and oncology. The quantification is highly dependent on the protocol of acquisition and reconstruction of the image, especially in low activity tumours. During adjusting acquisition and reconstruction protocols available in our Siemens Biograph mCT scanner for EARL (ResEARch 4 Life®) [18F]FDG-PET/CT accreditation requirements, we developed reconstruction protocols which will be used in PET based radiotherapy planning able to reduce inter-/intra-institute variability in Standard Uptake Value (SUV) results, and to bring Recovery Coefficient to 1 as close as possible for Image Quality NEMA 2007 phantom. Primary and secondary tumours from two patients were assessed by four independent evaluators. The influence of reconstruction protocols on tumour clinical assessment was presented. We proposed the improvement route for EARL accredited protocols so that they may be developed in classes to take advantage of scanner possibilities. The application of optimized reconstruction protocol eliminates the need of partial volume corrections.

[Multidisciplinary protocol for computed tomography imaging and angiographic embolization of splenic injury due to trauma: assessment of pre-protocol and post-protocol outcomes].

PubMed

Koo, M; Sabaté, A; Magalló, P; García, M A; Domínguez, J; de Lama, M E; López, S

2011-11-01

To assess conservative treatment of splenic injury due to trauma, following a protocol for computed tomography (CT) and angiographic embolization. To quantify the predictive value of CT for detecting bleeding and need for embolization. The care protocol developed by the multidisciplinary team consisted of angiography with embolization of lesions revealed by contrast extravasation under CT as well as embolization of grade III-V injuries observed, or grade I-II injuries causing hemodynamic instability and/or need for blood transfusion. We collected data on demographic variables, injury severity score (ISS), angiographic findings, and injuries revealed by CT. Pre-protocol and post-protocol outcomes were compared. The sensitivity and specificity of CT findings were calculated for all patients who required angiographic embolization. Forty-four and 30 angiographies were performed in the pre- and post-protocol periods, respectively. The mean (SD) ISSs in the two periods were 25 (11) and 26 (12), respectively. A total of 24 (54%) embolizations were performed in the pre-protocol period and 28 (98%) after implementation of the protocol. Two and 7 embolizations involved the spleen in the 2 periods, respectively; abdominal laparotomies numbered 32 and 25, respectively, and 10 (31%) vs 4 (16%) splenectomies were performed. The specificity and sensitivity values for contrast extravasation found on CT and followed by embolization were 77.7% and 79.5%. The implementation of this multidisciplinary protocol using CT imaging and angiographic embolization led to a decrease in the number of splenectomies. The protocol allows us to take a more conservative treatment approach.

Improved Peritoneal Cavity and Abdominal Organ Imaging Using a Biphasic Contrast Agent Protocol and Spectral Photon Counting Computed Tomography K-Edge Imaging.

PubMed

Si-Mohamed, Salim; Thivolet, Arnaud; Bonnot, Pierre-Emmanuel; Bar-Ness, Daniel; Képénékian, Vahan; Cormode, David P; Douek, Philippe; Rousset, Pascal

2018-05-23

To validate in vitro the capability of a high-spatial-resolution prototype spectral photon-counting computed tomography (SPCCT) scanner to differentiate between 2 contrast agents and to assess in vivo the image quality and the feasibility to image the peritoneal cavity in rats using the 2 contrast agents simultaneously within the vascular and peritoneal compartments. The authors performed SPCCT imaging (100 mAs, 120 kVp) with energy bin thresholds set to 30, 51, 64, 72, and 85 keV in vitro on a custom-made polyoxymethylene cylindrical phantom consisting of tubes with dilutions of both contrast agents and in vivo on 2 groups of adult rats using 2 injection protocols. Approval from the institutional animal ethics committee was obtained. One group received macrocylic gadolinium chelate intraperitoneal (IP) and iodine intravenous (IV) injections (protocol A, n = 3), whereas the second group received iodine IP and gadolinium IV (protocol B, n = 3). Helical scans were performed 35 minutes after IP injection and 20 seconds after IV injection. The SPCCT and contrast material images, that is, iodine and gadolinium maps, were reconstructed with a field of view of 160 mm, an isotropic voxel size of 250 μm, and a matrix size of 640 × 640 pixels using a soft reconstruction kernel. The SPCCT images were reconstructed with 2 different spatial resolutions to compare the image quality (sharpness, diagnostic quality, and organ visualization) of SPCCT (250 μm) with single-energy computed tomography (CT) (600 μm). Two radiologists evaluated the peritoneal opacification index in 13 regions (score = 0-3 per region) on each type of image. Concentrations of contrast agents were measured in the organs of interest. In vitro, the concentration measurements correlated well with the expected concentrations. The linear regressions both had R values of 0.99, slopes of 0.84 and 0.87, and offsets at -0.52 and -0.38 mg/mL for iodine and gadolinium, respectively. In vivo, the SPCCT images were of better diagnostic quality, with increased sharpness compared with the CT-like images (P < 0.0001). Intraperitoneal diffusion was excellent, with similar peritoneal opacification index on SPCCT images and overlay of contrast material maps (P = 1) without a significant difference between protocol A (37.0 ± 1.7) and protocol B (35.3 ± 1.5) (P = 0.34). Only the contrast material maps demonstrated clear visual separation of the contrast agents, allowing specific quantification of the physiological enhancement in the liver, spleen, and kidney and the urinary clearance in the renal pelvis and bladder. Renal excretion of the contrast agents injected IP was observed and was consistent with blood diffusion. Spectral photon-counting CT can be used to perform a complete peritoneal dual-contrast protocol, enabling a good assessment of the peritoneal cavity and abdominal organs in rats.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Pulmonary Venous Anatomy Imaging with Low-Dose, Prospectively ECG-Triggered, High-Pitch 128-Slice Dual Source Computed Tomography

PubMed Central

Thai, Wai-ee; Wai, Bryan; Lin, Kaity; Cheng, Teresa; Heist, E. Kevin; Hoffmann, Udo; Singh, Jagmeet; Truong, Quynh A.

2012-01-01

Background Efforts to reduce radiation from cardiac computed tomography (CT) are essential. Using a prospectively triggered, high-pitch dual source CT (DSCT) protocol, we aim to determine the radiation dose and image quality (IQ) in patients undergoing pulmonary vein (PV) imaging. Methods and Results In 94 patients (61±9 years, 71% male) who underwent 128-slice DSCT (pitch 3.4), radiation dose and IQ were assessed and compared between 69 patients in sinus rhythm (SR) and 25 in atrial fibrillation (AF). Radiation dose was compared in a subset of 19 patients with prior retrospective or prospectively triggered CT PV scans without high-pitch. In a subset of 18 patients with prior magnetic resonance imaging (MRI) for PV assessment, PV anatomy and scan duration were compared to high-pitch CT. Using the high-pitch protocol, total effective radiation dose was 1.4 [1.3, 1.9] mSv, with no difference between SR and AF (1.4 vs 1.5 mSv, p=0.22). No high-pitch CT scans were non-diagnostic or had poor IQ. Radiation dose was reduced with high-pitch (1.6 mSv) compared to standard protocols (19.3 mSv, p<0.0001). This radiation dose reduction was seen with SR (1.5 vs 16.7 mSv, p<0.0001) but was more profound with AF (1.9 vs 27.7 mSv, p=0.039). There was excellent agreement of PV anatomy (kappa 0.84, p<0.0001), and a shorter CT scan duration (6 minutes) compared to MRI (41 minutes, p<0.0001). Conclusions Using a high-pitch DSCT protocol, PV imaging can be performed with minimal radiation dose, short scan acquisition, and excellent IQ in patients with SR or AF. This protocol highlights the success of new cardiac CT technology to minimize radiation exposure, giving clinicians a new low-dose imaging alternative to assess PV anatomy. PMID:22586259

Comparison of seven optical clearing methods for mouse brain

NASA Astrophysics Data System (ADS)

Wan, Peng; Zhu, Jingtan; Yu, Tingting; Zhu, Dan

2018-02-01

Recently, a variety of tissue optical clearing techniques have been developed to reduce light scattering for imaging deeper and three-dimensional reconstruction of tissue structures. Combined with optical imaging techniques and diverse labeling methods, these clearing methods have significantly promoted the development of neuroscience. However, most of the protocols were proposed aiming for specific tissue type. Though there are some comparison results, the clearing methods covered are limited and the evaluation indices are lack of uniformity, which made it difficult to select a best-fit protocol for clearing in practical applications. Hence, it is necessary to systematically assess and compare these clearing methods. In this work, we evaluated the performance of seven typical clearing methods, including 3DISCO, uDISCO, SeeDB, ScaleS, ClearT2, CUBIC and PACT, on mouse brain samples. First, we compared the clearing capability on both brain slices and whole-brains by observing brain transparency. Further, we evaluated the fluorescence preservation and the increase of imaging depth. The results showed that 3DISCO, uDISCO and PACT posed excellent clearing capability on mouse brains, ScaleS and SeeDB rendered moderate transparency, while ClearT2 was the worst. Among those methods, ScaleS was the best on fluorescence preservation, and PACT achieved the highest increase of imaging depth. This study is expected to provide important reference for users in choosing most suitable brain optical clearing method.

Investigation into Practical Implementations of a Zero Knowledge Protocol.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marleau, Peter; Krentz-Wee, Rebecca E.

In recent years, the concept of Zero Knowledge Protocols (ZKP) as a useful approach to nuclear warhead verification has become increasingly popular. Several implementations of ZKP have been proposed, driving technology development toward proof of concept demonstrations. Whereas proposed implementations seem to fall within the general class of template-based techniques, all physical implementations of ZKPs proposed to date have a complication: once the instrumentation is prepared, it is no longer authenticatable; the instrument physically contains sensitive information. In this work we explore three different concepts that may offer more authenticatable and practical ZKP implementations and evaluate the sensitive information thatmore » may be at risk when doing so: sharing a subset of detector counts in a preloaded image (with spatial information removed), real-time image subtraction, and a new concept, CONfirmation using a Fast-neutron Imaging Detector with Anti-image NULL-positive Time Encoding (CONFIDANTE). CONFIDANTE promises to offer an almost ideal implementation of ZKP: a positive result is indicated by a constant rate at all times enabling the monitoring party the possibility of full access to the instrument before, during, and after confirmation. A prototype of CONFIDANTE was designed, built, and its performance evaluated in a series of measurements of several objects including a set of plutonium dioxide Hemispheres. Very encouraging results proving feasibility are presented. 1 Rebecca is currently a graduate student in Nuclear Engineering at UC Berkeley« less

SU-F-I-46: Optimizing Dose Reduction in Adult Head CT Protocols While Maintaining Image Quality in Postmortem Head Scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipnharski, I; Carranza, C; Quails, N

Purpose: To optimize adult head CT protocol by reducing dose to an appropriate level while providing CT images of diagnostic quality. Methods: Five cadavers were scanned from the skull base to the vertex using a routine adult head CT protocol (120 kVp, 270 mA, 0.75 s rotation, 0.5 mm × 32 detectors, 70.8 mGy CTDIvol) followed by seven reduced-dose protocols with varying combinations of reduced tube current, reduced rotation time, and increased detectors with CTDIvol ranging from 38.2 to 65.6 mGy. Organ doses were directly measured with 21 OSL dosimeters placed on the surface and implanted in the head bymore » a neurosurgeon. Two neuroradiologists assessed grey-white matter differentiation, fluid space, ventricular size, midline shift, brain mass, edema, ischemia, and skull fractures on a three point scale: (1) Unacceptable, (2) Borderline Acceptable, and (3) Acceptable. Results: For the standard scan, doses to the skin, lens of the eye, salivary glands, thyroid, and brain were 37.55 mGy, 49.65 mGy, 40.67 mGy, 4.63 mGy, and 27.33 mGy, respectively. Two cadavers had cerebral edema due to changing dynamics of postmortem effects, causing the grey-white matter differentiation to appear less distinct. Two cadavers with preserved grey-white matter received acceptable scores for all image quality features for the protocol with a CTDIvol of 57.3 mGy, allowing organ dose savings ranging from 34% to 45%. One cadaver allowed for greater dose reduction for the protocol with a CTDIvol of 42 mGy. Conclusion: Efforts to optimize scan protocol should consider both dose and clinical image quality. This is made possible with postmortem subjects, whose brains are similar to patients, allowing for an investigation of ideal scan parameters. Radiologists at our institution accepted scan protocols acquired with lower scan parameters, with CTDIvol values closer to the American College of Radiology’s (ACR) Achievable Dose level of 57 mGy.« less

Magnetic Resonance and Ultrasound Image Fusion Supported Transperineal Prostate Biopsy Using the Ginsburg Protocol: Technique, Learning Points, and Biopsy Results.

PubMed

Hansen, Nienke; Patruno, Giulio; Wadhwa, Karan; Gaziev, Gabriele; Miano, Roberto; Barrett, Tristan; Gnanapragasam, Vincent; Doble, Andrew; Warren, Anne; Bratt, Ola; Kastner, Christof

2016-08-01

Prostate biopsy supported by transperineal image fusion has recently been developed as a new method to the improve accuracy of prostate cancer detection. To describe the Ginsburg protocol for transperineal prostate biopsy supported by multiparametric magnetic resonance imaging (mpMRI) and transrectal ultrasound (TRUS) image fusion, provide learning points for its application, and report biopsy results. The article is supplemented by a Surgery in Motion video. This single-centre retrospective outcome study included 534 patients from March 2012 to October 2015. A total of 107 had no previous prostate biopsy, 295 had benign TRUS-guided biopsies, and 159 were on active surveillance for low-risk cancer. A Likert scale reported mpMRI for suspicion of cancer from 1 (no suspicion) to 5 (cancer highly likely). Transperineal biopsies were obtained under general anaesthesia using BiopSee fusion software (Medcom, Darmstadt, Germany). All patients had systematic biopsies, two cores from each of 12 anatomic sectors. Likert 3-5 lesions were targeted with a further two cores per lesion. Any cancer and Gleason score 7-10 cancer on biopsy were noted. Descriptive statistics and positive predictive values (PPVs) and negative predictive values (NPVs) were calculated. The detection rate of Gleason score 7-10 cancer was similar across clinical groups. Likert scale 3-5 MRI lesions were reported in 378 (71%) of the patients. Cancer was detected in 249 (66%) and Gleason score 7-10 cancer was noted in 157 (42%) of these patients. PPV for detecting 7-10 cancer was 0.15 for Likert score 3, 0.43 for score 4, and 0.63 for score 5. NPV of Likert 1-2 findings was 0.87 for Gleason score 7-10 and 0.97 for Gleason score ≥4+3=7 cancer. Limitations include lack of data on complications. Transperineal prostate biopsy supported by MRI/TRUS image fusion using the Ginsburg protocol yielded high detection rates of Gleason score 7-10 cancer. Because the NPV for excluding Gleason score 7-10 cancer was very high, prostate biopsies may not be needed for all men with elevated prostate-specific antigen values and nonsuspicious mpMRI. We present our technique to sample (biopsy) the prostate by the transperineal route (the area between the scrotum and the anus) to detect prostate cancer using a fusion of magnetic resonance and ultrasound images to guide the sampling. Copyright © 2016 European Association of Urology. All rights reserved.

Evaluation of Cross-Protocol Stability of a Fully Automated Brain Multi-Atlas Parcellation Tool.

PubMed

Liang, Zifei; He, Xiaohai; Ceritoglu, Can; Tang, Xiaoying; Li, Yue; Kutten, Kwame S; Oishi, Kenichi; Miller, Michael I; Mori, Susumu; Faria, Andreia V

2015-01-01

Brain parcellation tools based on multiple-atlas algorithms have recently emerged as a promising method with which to accurately define brain structures. When dealing with data from various sources, it is crucial that these tools are robust for many different imaging protocols. In this study, we tested the robustness of a multiple-atlas, likelihood fusion algorithm using Alzheimer's Disease Neuroimaging Initiative (ADNI) data with six different protocols, comprising three manufacturers and two magnetic field strengths. The entire brain was parceled into five different levels of granularity. In each level, which defines a set of brain structures, ranging from eight to 286 regions, we evaluated the variability of brain volumes related to the protocol, age, and diagnosis (healthy or Alzheimer's disease). Our results indicated that, with proper pre-processing steps, the impact of different protocols is minor compared to biological effects, such as age and pathology. A precise knowledge of the sources of data variation enables sufficient statistical power and ensures the reliability of an anatomical analysis when using this automated brain parcellation tool on datasets from various imaging protocols, such as clinical databases.

Towards building high performance medical image management system for clinical trials

NASA Astrophysics Data System (ADS)

Wang, Fusheng; Lee, Rubao; Zhang, Xiaodong; Saltz, Joel

2011-03-01

Medical image based biomarkers are being established for therapeutic cancer clinical trials, where image assessment is among the essential tasks. Large scale image assessment is often performed by a large group of experts by retrieving images from a centralized image repository to workstations to markup and annotate images. In such environment, it is critical to provide a high performance image management system that supports efficient concurrent image retrievals in a distributed environment. There are several major challenges: high throughput of large scale image data over the Internet from the server for multiple concurrent client users, efficient communication protocols for transporting data, and effective management of versioning of data for audit trails. We study the major bottlenecks for such a system, propose and evaluate a solution by using a hybrid image storage with solid state drives and hard disk drives, RESTfulWeb Services based protocols for exchanging image data, and a database based versioning scheme for efficient archive of image revision history. Our experiments show promising results of our methods, and our work provides a guideline for building enterprise level high performance medical image management systems.

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement.

PubMed

Liu, Jun; Wilson, John; Davis, Claire; Peyton, Anthony

2017-11-07

This paper elaborates the sample preparation protocols required to obtain optimal domain patterns using the Bitter method, focusing on the extra steps compared to standard metallographic sample preparation procedures. The paper proposes a novel bespoke rig for dynamic domain imaging with in situ BH (magnetic hysteresis) measurements and elaborates the protocols for the sensor preparation and the use of the rig to ensure accurate BH measurement. The protocols for static and ordinary dynamic domain imaging (without in situ BH measurements) are also presented. The reported method takes advantage of the convenience and high sensitivity of the traditional Bitter method and enables in situ BH measurement without interrupting or interfering with the domain wall movement processes. This facilitates establishing a direct and quantitative link between the domain wall movement processes-microstructural feature interactions in ferritic steels with their BH loops. This method is anticipated to become a useful tool for the fundamental study of microstructure-magnetic property relationships in steels and to help interpret the electromagnetic sensor signals for non-destructive evaluation of steel microstructures.

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement

PubMed Central

Liu, Jun; Wilson, John; Davis, Claire; Peyton, Anthony

2017-01-01

This paper elaborates the sample preparation protocols required to obtain optimal domain patterns using the Bitter method, focusing on the extra steps compared to standard metallographic sample preparation procedures. The paper proposes a novel bespoke rig for dynamic domain imaging with in situ BH (magnetic hysteresis) measurements and elaborates the protocols for the sensor preparation and the use of the rig to ensure accurate BH measurement. The protocols for static and ordinary dynamic domain imaging (without in situ BH measurements) are also presented. The reported method takes advantage of the convenience and high sensitivity of the traditional Bitter method and enables in situ BH measurement without interrupting or interfering with the domain wall movement processes. This facilitates establishing a direct and quantitative link between the domain wall movement processes–microstructural feature interactions in ferritic steels with their BH loops. This method is anticipated to become a useful tool for the fundamental study of microstructure–magnetic property relationships in steels and to help interpret the electromagnetic sensor signals for non-destructive evaluation of steel microstructures. PMID:29155796

TH-C-18A-08: A Management Tool for CT Dose Monitoring, Analysis, and Protocol Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, J; Chan, F; Newman, B

2014-06-15

Purpose: To develop a customizable tool for enterprise-wide managing of CT protocols and analyzing radiation dose information of CT exams for a variety of quality control applications Methods: All clinical CT protocols implemented on the 11 CT scanners at our institution were extracted in digital format. The original protocols had been preset by our CT management team. A commercial CT dose tracking software (DoseWatch,GE healthcare,WI) was used to collect exam information (exam date, patient age etc.), scanning parameters, and radiation doses for all CT exams. We developed a Matlab-based program (MathWorks,MA) with graphic user interface which allows to analyze themore » scanning protocols with the actual dose estimates, and compare the data to national (ACR,AAPM) and internal reference values for CT quality control. Results: The CT protocol review portion of our tool allows the user to look up the scanning and image reconstruction parameters of any protocol on any of the installed CT systems among about 120 protocols per scanner. In the dose analysis tool, dose information of all CT exams (from 05/2013 to 02/2014) was stratified on a protocol level, and within a protocol down to series level, i.e. each individual exposure event. This allows numerical and graphical review of dose information of any combination of scanner models, protocols and series. The key functions of the tool include: statistics of CTDI, DLP and SSDE, dose monitoring using user-set CTDI/DLP/SSDE thresholds, look-up of any CT exam dose data, and CT protocol review. Conclusion: our inhouse CT management tool provides radiologists, technologists and administration a first-hand near real-time enterprise-wide knowledge on CT dose levels of different exam types. Medical physicists use this tool to manage CT protocols, compare and optimize dose levels across different scanner models. It provides technologists feedback on CT scanning operation, and knowledge on important dose baselines and thresholds.« less

Ultrasonic Shear Wave Elasticity Imaging (SWEI) Sequencing and Data Processing Using a Verasonics Research Scanner

PubMed Central

Deng, Yufeng; Rouze, Ned C.; Palmeri, Mark L.; Nightingale, Kathryn R.

2017-01-01

Ultrasound elasticity imaging has been developed over the last decade to estimate tissue stiffness. Shear wave elasticity imaging (SWEI) quantifies tissue stiffness by measuring the speed of propagating shear waves following acoustic radiation force excitation. This work presents the sequencing and data processing protocols of SWEI using a Verasonics system. The selection of the sequence parameters in a Verasonics programming script is discussed in detail. The data processing pipeline to calculate group shear wave speed (SWS), including tissue motion estimation, data filtering, and SWS estimation is demonstrated. In addition, the procedures for calibration of beam position, scanner timing, and transducer face heating are provided to avoid SWS measurement bias and transducer damage. PMID:28092508

A Simple Method for Reproducing Orbital Plots for Illustration Using Microsoft Paint and Microsoft Excel

NASA Astrophysics Data System (ADS)

Niebuhr, Cole

2018-04-01

Papers published in the astronomical community, particularly in the field of double star research, often contain plots that display the positions of the component stars relative to each other on a Cartesian coordinate plane. Due to the complexities of plotting a three-dimensional orbit into a two-dimensional image, it is often difficult to include an accurate reproduction of the orbit for comparison purposes. Methods to circumvent this obstacle do exist; however, many of these protocols result in low-quality blurred images or require specific and often expensive software. Here, a method is reported using Microsoft Paint and Microsoft Excel to produce high-quality images with an accurate reproduction of a partial orbit.

Digital retinal imaging in a residency-based patient-centered medical home.

PubMed

Newman, Robert; Cummings, Doyle M; Doherty, Lisa; Patel, Nick R

2012-03-01

Diabetic retinopathy is the leading cause of blindness in adults in the United States, and early screening/treatment may preserve vision. This study examined the feasibility of using non-mydriatic digital retinal imaging (DRI) for retinopathy screening in a busy family medicine residency program at the point of care using a nurse-driven protocol. We compared the number of diabetics screened during a 1-year period before and after DRI protocol implementation. We also determined the prevalence of retinopathy, assessed patient satisfaction with the alternative screening process, and tracked ophthalmologic appointment compliance for patients referred because of abnormal screening results. Screening approximately doubled from 161 patients/year before the protocol to 330 patients/year after protocol implementation. However, DRI screening had no impact on ophthalmologic appointment compliance; only 58% of 153 patients referred for ophthalmologic evaluation because of positive screening findings completed their referral appointment. Seven cases needing urgent ophthalmologic treatment were identified. Satisfaction with primary care retinopathy screening was high. Use of a nurse-driven protocol for digital retinal imaging at the point of care dramatically improves rates of annual retinopathy screening in academic family medicine practice and can identify patients who require subspecialty referral. However, DRI screening does not improve visit compliance rates with ophthalmologists for evaluation and management.

Interfacing the PACS and the HIS: results of a 5-year implementation.

PubMed

Kinsey, T V; Horton, M C; Lewis, T E

2000-01-01

An interface was created between the Department of Defense's hospital information system (HIS) and its two picture archiving and communication system (PACS)-based radiology information systems (RISs). The HIS is called the Composite Healthcare Computer System (CHCS), and the RISs are called the Medical Diagnostic Imaging System (MDIS) and the Digital Imaging Network (DIN)-PACS. Extensive mapping between dissimilar data protocols was required to translate data from the HIS into both RISs. The CHCS uses a Health Level 7 (HL7) protocol, whereas the MDIS uses the American College of Radiology-National Electrical Manufacturers Association 2.0 protocol and the DIN-PACS uses the Digital Imaging and Communications in Medicine (DICOM) 3.0 protocol. An interface engine was required to change some data formats, as well as to address some nonstandard HL7 data being output from the CHCS. In addition, there are differences in terminology between fields and segments in all three protocols. This interface is in use at 20 military facilities throughout the world. The interface reduces the amount of manual entry into more than one automated system to the smallest level possible. Data mapping during installation saved time, improved productivity, and increased user acceptance during PACS implementation. It also resulted in more standardized database entries in both the HIS (CHCS) and the RIS (PACS).

[Can the degree of renal artery stenosis be automatically quantified?].

PubMed

Cherrak, I; Jaulent, M C; Azizi, M; Plouin, P F; Degoulet, P; Chatellier, G

2000-08-01

The objective of the reported study is to validate a computer system, QUASAR, dedicated to the quantification of renal artery stenoses. This system estimates automatically the reference diameter and calculates the minimum diameter to compute a degree of stenosis. A hundred and eighty images of atheromatous stenoses between 10% and 80% were collected from two French independent protocols. For the 49 images of the EMMA protocol, the results from QUASAR were compared with the visual estimation of an initial investigator and with the results from a reference method based on a panel of fixe experienced experts. For the 131 images of the ASTARTE protocol, the results from QUASAR were compared with those from a semi-automatic quantification system and with those from a system based on densitometric analysis. The present work validates QUASAR in a population of narrow atheromatous stenoses (> 50%). In the context of the EMMA protocol, QUASAR is not significantly different from the mean of the fixe experts. It is unbiased and more precise than the estimation of a single investigator. In the context of the ASTARTE protocol, there is no significant difference between the three methods for the stenoses higher than 50%, however, globally, QUASAR surestimates significantly (up to 10%) the degree of stenosis.

Objective criteria for acceptability and constancy tests of digital subtraction angiography.

PubMed

de las Heras, Hugo; Torres, Ricardo; Fernández-Soto, José Miguel; Vañó, Eliseo

2016-01-01

Demonstrate an objective procedure to quantify image quality in digital subtraction angiography (DSA) and suggest thresholds for acceptability and constancy tests. Series of images were obtained in a DSA system simulating a small (paediatric) and a large patient using the dynamic phantom described in the IEC and DIN standards for acceptance tests of DSA equipment. Image quality was quantified using measurements of contrast-to-noise ratio (CNR). Overall scores combining the CNR of 10-100 mg/ml Iodine at a vascular diameter of 1-4 mm in a homogeneous background were defined. Phantom entrance surface air kerma (Ka,e) was measured with an ionisation chamber. The visibility of a low-contrast vessel in DSA images has been identified with a CNR value of 0.50 ± 0.03. Despite using 14 times more Ka,e (8.85 vs 0.63 mGy/image), the protocol for large patients showed a decrease in the overall score CNRsum of 67% (4.21 ± 0.06 vs 2.10 ± 0.05). The uncertainty in the results of the objective method was below 5%. Objective evaluation of DSA images using CNR is feasible with dedicated phantom measurements. An objective methodology has been suggested for acceptance tests compliant with the IEC/DIN standards. The defined overall scores can serve to fix a reproducible baseline for constancy tests, as well as to study the device stability within one acquisition series and compare different imaging protocols. This work provides aspects that have not been included in the recent European guidelines on Criteria for Acceptability of Medical Radiological Equipment. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Using image analysis for quantitative assessment of needle bladder rust disease of Norway spruce.

PubMed

Ganthaler, A; Losso, A; Mayr, S

2018-06-01

High elevation spruce forests of the European Alps are frequently infected by the needle rust Chrysomyxa rhododendri , a pathogen causing remarkable defoliation, reduced tree growth and limited rejuvenation. Exact quantification of the disease severity on different spatial scales is crucial for monitoring, management and resistance breeding activities. Based on the distinct yellow discolouration of attacked needles, it was investigated whether image analysis of digital photographs can be used to quantify disease severity and to improve phenotyping compared to conventional assessment in terms of time, effort and application range. The developed protocol for preprocessing and analysis of digital RGB images enabled identification of disease symptoms and healthy needle areas on images obtained in ground surveys (total number of analysed images n  =   62) and by the use of a semiprofessional quadcopter ( n  =   13). Obtained disease severities correlated linearly with results obtained by manual counting of healthy and diseased needles for all approaches, including images of individual branches with natural background ( R 2  = 0.87) and with black background ( R 2  = 0.95), juvenile plants ( R 2  = 0.94), and top views and side views of entire tree crowns of adult trees ( R 2  = 0.98 and 0.88, respectively). Results underline that a well-defined signal related to needle bladder rust symptoms of Norway spruce can be extracted from images recorded by standard digital cameras and using drones. The presented protocol enables precise and time-efficient quantification of disease symptoms caused by C. rhododendri and provides several advantages compared to conventional assessment by manual counting or visual estimations.

Large-scale retrieval for medical image analytics: A comprehensive review.

PubMed

Li, Zhongyu; Zhang, Xiaofan; Müller, Henning; Zhang, Shaoting

2018-01-01

Over the past decades, medical image analytics was greatly facilitated by the explosion of digital imaging techniques, where huge amounts of medical images were produced with ever-increasing quality and diversity. However, conventional methods for analyzing medical images have achieved limited success, as they are not capable to tackle the huge amount of image data. In this paper, we review state-of-the-art approaches for large-scale medical image analysis, which are mainly based on recent advances in computer vision, machine learning and information retrieval. Specifically, we first present the general pipeline of large-scale retrieval, summarize the challenges/opportunities of medical image analytics on a large-scale. Then, we provide a comprehensive review of algorithms and techniques relevant to major processes in the pipeline, including feature representation, feature indexing, searching, etc. On the basis of existing work, we introduce the evaluation protocols and multiple applications of large-scale medical image retrieval, with a variety of exploratory and diagnostic scenarios. Finally, we discuss future directions of large-scale retrieval, which can further improve the performance of medical image analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Neurologic 3D MR Spectroscopic Imaging with Low-Power Adiabatic Pulses and Fast Spiral Acquisition

PubMed Central

Gagoski, Borjan A.; Sorensen, A. Gregory

2012-01-01

Purpose: To improve clinical three-dimensional (3D) MR spectroscopic imaging with more accurate localization and faster acquisition schemes. Materials and Methods: Institutional review board approval and patient informed consent were obtained. Data were acquired with a 3-T MR imager and a 32-channel head coil in phantoms, five healthy volunteers, and five patients with glioblastoma. Excitation was performed with localized adiabatic spin-echo refocusing (LASER) by using adiabatic gradient-offset independent adiabaticity wideband uniform rate and smooth truncation (GOIA-W[16,4]) pulses with 3.5-msec duration, 20-kHz bandwidth, 0.81-kHz amplitude, and 45-msec echo time. Interleaved constant-density spirals simultaneously encoded one frequency and two spatial dimensions. Conventional phase encoding (PE) (1-cm3 voxels) was performed after LASER excitation and was the reference standard. Spectra acquired with spiral encoding at similar and higher spatial resolution and with shorter imaging time were compared with those acquired with PE. Metabolite levels were fitted with software, and Bland-Altman analysis was performed. Results: Clinical 3D MR spectroscopic images were acquired four times faster with spiral protocols than with the elliptical PE protocol at low spatial resolution (1 cm3). Higher-spatial-resolution images (0.39 cm3) were acquired twice as fast with spiral protocols compared with the low-spatial-resolution elliptical PE protocol. A minimum signal-to-noise ratio (SNR) of 5 was obtained with spiral protocols under these conditions and was considered clinically adequate to reliably distinguish metabolites from noise. The apparent SNR loss was not linear with decreasing voxel sizes because of longer local T2* times. Improvement of spectral line width from 4.8 Hz to 3.5 Hz was observed at high spatial resolution. The Bland-Altman agreement between spiral and PE data is characterized by narrow 95% confidence intervals for their differences (0.12, 0.18 of their means). GOIA-W(16,4) pulses minimize chemical-shift displacement error to 2.1%, reduce nonuniformity of excitation to 5%, and eliminate the need for outer volume suppression. Conclusion: The proposed adiabatic spiral 3D MR spectroscopic imaging sequence can be performed in a standard clinical MR environment. Improvements in image quality and imaging time could enable more routine acquisition of spectroscopic data than is possible with current pulse sequences. © RSNA, 2011 PMID:22187628

Imaging the beating heart in the mouse using intravital microscopy techniques

PubMed Central

Vinegoni, Claudio; Aguirre, Aaron D; Lee, Sungon; Weissleder, Ralph

2017-01-01

Real-time microscopic imaging of moving organs at single-cell resolution represents a major challenge in studying complex biology in living systems. Motion of the tissue from the cardiac and respiratory cycles severely limits intravital microscopy by compromising ultimate spatial and temporal imaging resolution. However, significant recent advances have enabled single-cell resolution imaging to be achieved in vivo. In this protocol, we describe experimental procedures for intravital microscopy based on a combination of thoracic surgery, tissue stabilizers and acquisition gating methods, which enable imaging at the single-cell level in the beating heart in the mouse. Setup of the model is typically completed in 1 h, which allows 2 h or more of continuous cardiac imaging. This protocol can be readily adapted for the imaging of other moving organs, and it will therefore broadly facilitate in vivo high-resolution microscopy studies. PMID:26492138

An Abbreviated Protocol for High-Risk Screening Breast MRI Saves Time and Resources.

PubMed

Harvey, Susan C; Di Carlo, Phillip A; Lee, Bonmyong; Obadina, Eniola; Sippo, Dorothy; Mullen, Lisa

2016-04-01

To review the ability of an abbreviated, high-risk, screening, breast MRI protocol to detect cancer and save resources. High-risk screening breast MR images were reviewed, from both an abbreviated protocol and a full diagnostic protocol. Differences in cancer detection, scanner utilization, interpretation times, and need for additional imaging were recorded in an integrated data form, and reviewed and compared. A total of 568 MRI cases were reviewed, with the abbreviated and full protocols. No difference was found in the number of cancers detected. Scan times were decreased by 18.8 minutes per case, for a total of 10,678 minutes (178 hours). Interpretation time, on average, was 1.55 minutes for the abbreviated protocol, compared with 6.43 minutes for the full protocol. Review of the full protocol led to a significant change in the final BI-RADS(®) assessment in 12 of 568 (2.1%) cases. Abbreviated MRI is as effective as full-protocol MRI for demonstration of cancers in the high-risk screening setting, with only 12 (2.1%) cases recommended for additional MRI evaluation. The efficiency and resource savings of an abbreviated protocol would be significant, and would allow for opportunities to provide MRI for additional patients, as well as improved radiologist time management and workflow, with the potential to add real-time MRI interpretation or double reading. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

An Abbreviated Protocol for High-Risk Screening Breast MRI Saves Time and Resources.

PubMed

Harvey, Susan C; Di Carlo, Phillip A; Lee, Bonmyong; Obadina, Eniola; Sippo, Dorothy; Mullen, Lisa

2016-11-01

To review the ability of an abbreviated, high-risk, screening, breast MRI protocol to detect cancer and save resources. High-risk screening breast MR images were reviewed, from both an abbreviated protocol and a full diagnostic protocol. Differences in cancer detection, scanner utilization, interpretation times, and need for additional imaging were recorded in an integrated data form, and reviewed and compared. A total of 568 MRI cases were reviewed, with the abbreviated and full protocols. No difference was found in the number of cancers detected. Scan times were decreased by 18.8 minutes per case, for a total of 10,678 minutes (178 hours). Interpretation time, on average, was 1.55 minutes for the abbreviated protocol, compared with 6.43 minutes for the full protocol. Review of the full protocol led to a significant change in the final BI-RADS ® assessment in 12 of 568 (2.1%) cases. Abbreviated MRI is as effective as full-protocol MRI for demonstration of cancers in the high-risk screening setting, with only 12 (2.1 %) cases recommended for additional MRI evaluation. The efficiency and resource savings of an abbreviated protocol would be significant, and would allow for opportunities to provide MRI for additional patients, as well as improved radiologist time management and workflow, with the potential to add real-time MRI interpretation or double reading. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Digital imagery/telecytology. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.

PubMed

O'Brien, M J; Takahashi, M; Brugal, G; Christen, H; Gahm, T; Goodell, R M; Karakitsos, P; Knesel, E A; Kobler, T; Kyrkou, K A; Labbe, S; Long, E L; Mango, L J; McGoogan, E; Oberholzer, M; Reith, A; Winkler, C

1998-01-01

Optical digital imaging and its related technologies have applications in cytopathology that encompass training and education, image analysis, diagnosis, report documentation and archiving, and telecommunications. Telecytology involves the use of telecommunications to transmit cytology images for the purposes of diagnosis, consultation or education. This working paper provides a mainly informational overview of optical digital imaging and summarizes current technologic resources and applications and some of the ethical and legal implications of the use of these new technologies in cytopathology. Computer hardware standards for optical digital imagery will continue to be driven mainly by commercial interests and nonmedical imperatives, but professional organizations can play a valuable role in developing recommendations or standards for digital image sampling, documentation, archiving, authenticity safeguards and teleconsultation protocols; in addressing patient confidentiality and ethical, legal and informed consent issues; and in providing support for quality assurance and standardization of digital image-based testing. There is some evidence that high levels of accuracy for telepathology diagnosis can be achieved using existing dynamic systems, which may also be applicable to telecytology consultation. Static systems for both telepathology and telecytology, which have the advantage of considerably lower cost, appear to have lower levels of accuracy. Laboratories that maintain digital image databases should adopt practices and protocols that ensure patient confidentiality. Individuals participating in telecommunication of digital images for diagnosis should be properly qualified, meet licensing requirements and use procedures that protect patient confidentiality. Such individuals should be cognizant of the limitations of the technology and employ quality assurance practices that ensure the validity and accuracy of each consultation. Even in an informal teleconsultation setting one should define the extent of participation and be mindful of potential malpractice liability. Digital imagery applications will continue to present new opportunities and challenges. Position papers such as this are directed toward assisting the profession to stay informed and in control of these applications in the laboratory. Telecytology is an area in particular need of studies of good quality to provide data on factors affecting accuracy. New technologic approaches to addressing the issue of selective sampling in static image consultation are needed. The use of artificial intelligence software as an adjunct to enhance the accuracy and reproducibility of cytologic diagnosis of digital images in routine and consultation settings deserves to be pursued. Other telecytology-related issues that require clarification and the adoption of workable guidelines include interstate licensure and protocols to define malpractice liability.

PET/CT (and CT) instrumentation, image reconstruction and data transfer for radiotherapy planning.

PubMed

Sattler, Bernhard; Lee, John A; Lonsdale, Markus; Coche, Emmanuel

2010-09-01

The positron emission tomography in combination with CT in hybrid, cross-modality imaging systems (PET/CT) gains more and more importance as a part of the treatment-planning procedure in radiotherapy. Positron emission tomography (PET), as a integral part of nuclear medicine imaging and non-invasive imaging technique, offers the visualization and quantification of pre-selected tracer metabolism. In combination with the structural information from CT, this molecular imaging technique has great potential to support and improve the outcome of the treatment-planning procedure prior to radiotherapy. By the choice of the PET-Tracer, a variety of different metabolic processes can be visualized. First and foremost, this is the glucose metabolism of a tissue as well as for instance hypoxia or cell proliferation. This paper comprises the system characteristics of hybrid PET/CT systems. Acquisition and processing protocols are described in general and modifications to cope with the special needs in radiooncology. This starts with the different position of the patient on a special table top, continues with the use of the same fixation material as used for positioning of the patient in radiooncology while simulation and irradiation and leads to special processing protocols that include the delineation of the volumes that are subject to treatment planning and irradiation (PTV, GTV, CTV, etc.). General CT acquisition and processing parameters as well as the use of contrast enhancement of the CT are described. The possible risks and pitfalls the investigator could face during the hybrid-imaging procedure are explained and listed. The interdisciplinary use of different imaging modalities implies a increase of the volume of data created. These data need to be stored and communicated fast, safe and correct. Therefore, the DICOM-Standard provides objects and classes for this purpose (DICOM RT). Furthermore, the standard DICOM objects and classes for nuclear medicine (NM, PT) and computed tomography (CT) are used to communicate the actual image data created by the modalities. Care must be taken for data security, especially when transferring data across the (network-) borders of different hospitals. Overall, the most important precondition for successful integration of functional imaging in RT treatment planning is the goal orientated as well as close and thorough communication between nuclear medicine and radiotherapy departments on all levels of interaction (personnel, imaging protocols, GTV delineation, and selection of the data transfer method). Copyright 2010 European Society for Therapeutic Radiology and Oncology and European Association of Nuclear Medicine. Published by Elsevier Ireland Ltd.. All rights reserved.

Permission to Ponder

ERIC Educational Resources Information Center

Cutler, Kay M.; Moeller, Mary R.

2017-01-01

"In many ways, images are the vehicle of comprehension, thought, and action. We integrate parts of images, we remember images, we manipulate images." This quote from James E. Zull clarifies the rationale for a discussion protocol called Visual Thinking Strategies (VTS), in which teachers focus students' attention on an image and ask…

Diffusion tensor imaging of the sural nerve in normal controls☆

PubMed Central

Kim, Boklye; Srinivasan, Ashok; Sabb, Brian; Feldman, Eva L; Pop-Busui, Rodica

2016-01-01

Objective To develop a diffusion tensor imaging (DTI) protocol for assessing the sural nerve in healthy subjects. Methods Sural nerves in 25 controls were imaged using DTI at 3 T with 6, 15, and 32 gradient directions. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were computed from nerve regions of interest co-registered with T2-weighted images. Results Coronal images with 0.5(RL)×2.0(FH)×0.5(AP) mm3 resolution successfully localized the sural nerve. FA maps showed less variability with 32 directions (0.559±0.071) compared to 15(0.590±0.080) and 6(0.659±0.109). Conclusions Our DTI protocol was effective in imaging sural nerves in controls to establish normative FA/ADC, with potential to be used non-invasively in diseased nerves of patients. PMID:24908367

Design of a short nonuniform acquisition protocol for quantitative analysis in dynamic cardiac SPECT imaging - a retrospective 123 I-MIBG animal study.

PubMed

Zan, Yunlong; Long, Yong; Chen, Kewei; Li, Biao; Huang, Qiu; Gullberg, Grant T

2017-07-01

Our previous works have found that quantitative analysis of 123 I-MIBG kinetics in the rat heart with dynamic single-photon emission computed tomography (SPECT) offers the potential to quantify the innervation integrity at an early stage of left ventricular hypertrophy. However, conventional protocols involving a long acquisition time for dynamic imaging reduce the animal survival rate and thus make longitudinal analysis difficult. The goal of this work was to develop a procedure to reduce the total acquisition time by selecting nonuniform acquisition times for projection views while maintaining the accuracy and precision of estimated physiologic parameters. Taking dynamic cardiac imaging with 123 I-MIBG in rats as an example, we generated time activity curves (TACs) of regions of interest (ROIs) as ground truths based on a direct four-dimensional reconstruction of experimental data acquired from a rotating SPECT camera, where TACs represented as the coefficients of B-spline basis functions were used to estimate compartmental model parameters. By iteratively adjusting the knots (i.e., control points) of B-spline basis functions, new TACs were created according to two rules: accuracy and precision. The accuracy criterion allocates the knots to achieve low relative entropy between the estimated left ventricular blood pool TAC and its ground truth so that the estimated input function approximates its real value and thus the procedure yields an accurate estimate of model parameters. The precision criterion, via the D-optimal method, forces the estimated parameters to be as precise as possible, with minimum variances. Based on the final knots obtained, a new protocol of 30 min was built with a shorter acquisition time that maintained a 5% error in estimating rate constants of the compartment model. This was evaluated through digital simulations. The simulation results showed that our method was able to reduce the acquisition time from 100 to 30 min for the cardiac study of rats with 123 I-MIBG. Compared to a uniform interval dynamic SPECT protocol (1 s acquisition interval, 30 min acquisition time), the newly proposed protocol with nonuniform interval achieved comparable (K1 and k2, P = 0.5745 for K1 and P = 0.0604 for k2) or better (Distribution Volume, DV, P = 0.0004) performance for parameter estimates with less storage and shorter computational time. In this study, a procedure was devised to shorten the acquisition time while maintaining the accuracy and precision of estimated physiologic parameters in dynamic SPECT imaging. The procedure was designed for 123 I-MIBG cardiac imaging in rat studies; however, it has the potential to be extended to other applications, including patient studies involving the acquisition of dynamic SPECT data. © 2017 American Association of Physicists in Medicine.

MRI of the hip at 7T: feasibility of bone microarchitecture, high-resolution cartilage, and clinical imaging.

PubMed

Chang, Gregory; Deniz, Cem M; Honig, Stephen; Egol, Kenneth; Regatte, Ravinder R; Zhu, Yudong; Sodickson, Daniel K; Brown, Ryan

2014-06-01

To demonstrate the feasibility of performing bone microarchitecture, high-resolution cartilage, and clinical imaging of the hip at 7T. This study had Institutional Review Board approval. Using an 8-channel coil constructed in-house, we imaged the hips of 15 subjects on a 7T magnetic resonance imaging (MRI) scanner. We applied: 1) a T1-weighted 3D fast low angle shot (3D FLASH) sequence (0.23 × 0.23 × 1-1.5 mm(3) ) for bone microarchitecture imaging; 2) T1-weighted 3D FLASH (water excitation) and volumetric interpolated breath-hold examination (VIBE) sequences (0.23 × 0.23 × 1.5 mm(3) ) with saturation or inversion recovery-based fat suppression for cartilage imaging; 3) 2D intermediate-weighted fast spin-echo (FSE) sequences without and with fat saturation (0.27 × 0.27 × 2 mm) for clinical imaging. Bone microarchitecture images allowed visualization of individual trabeculae within the proximal femur. Cartilage was well visualized and fat was well suppressed on FLASH and VIBE sequences. FSE sequences allowed visualization of cartilage, the labrum (including cartilage and labral pathology), joint capsule, and tendons. This is the first study to demonstrate the feasibility of performing a clinically comprehensive hip MRI protocol at 7T, including high-resolution imaging of bone microarchitecture and cartilage, as well as clinical imaging. Copyright © 2013 Wiley Periodicals, Inc.

Muscle changes detected with diffusion-tensor imaging after long-distance running.

PubMed

Froeling, Martijn; Oudeman, Jos; Strijkers, Gustav J; Maas, Mario; Drost, Maarten R; Nicolay, Klaas; Nederveen, Aart J

2015-02-01

To develop a protocol for diffusion-tensor imaging (DTI) of the complete upper legs and to demonstrate feasibility of detection of subclinical sports-related muscle changes in athletes after strenuous exercise, which remain undetected by using conventional T2-weighted magnetic resonance (MR) imaging with fat suppression. The research was approved by the institutional ethics committee review board, and the volunteers provided written consent before the study. Five male amateur long-distance runners underwent an MR examination (DTI, T1-weighted MR imaging, and T2-weighted MR imaging with fat suppression) of both upper legs 1 week before, 2 days after, and 3 weeks after they participated in a marathon. The tensor eigenvalues (λ1, λ2, and λ3), the mean diffusivity, and the fractional anisotropy (FA) were derived from the DTI data. Data per muscle from the three time-points were compared by using a two-way mixed-design analysis of variance with a Bonferroni posthoc test. The DTI protocol allowed imaging of both complete upper legs with adequate signal-to-noise ratio and within a 20-minute imaging time. After the marathon, T2-weighted MR imaging revealed grade 1 muscle strains in nine of the 180 investigated muscles. The three eigenvalues, mean diffusivity, and FA were significantly increased (P < .05) in the biceps femoris muscle 2 days after running. Mean diffusivity and eigenvalues λ1 and λ2 were significantly (P < .05) increased in the semitendinosus and gracilis muscles 2 days after the marathon. A feasible method for DTI measurements of the upper legs was developed that fully included frequently injured muscles, such as hamstrings, in one single imaging session. This study also revealed changes in DTI parameters that over time were not revealed by qualitative T2-weighted MR imaging with fat suppression. © RSNA, 2014.

Research and implementation of SATA protocol link layer based on FPGA

NASA Astrophysics Data System (ADS)

Liu, Wen-long; Liu, Xue-bin; Qiang, Si-miao; Yan, Peng; Wen, Zhi-gang; Kong, Liang; Liu, Yong-zheng

2018-02-01

In order to solve the problem high-performance real-time, high-speed the image data storage generated by the detector. In this thesis, it choose an suitable portable image storage hard disk of SATA interface, it is relative to the existing storage media. It has a large capacity, high transfer rate, inexpensive, power-down data which is not lost, and many other advantages. This paper focuses on the link layer of the protocol, analysis the implementation process of SATA2.0 protocol, and build state machines. Then analyzes the characteristics resources of Kintex-7 FPGA family, builds state machines according to the agreement, write Verilog implement link layer modules, and run the simulation test. Finally, the test is on the Kintex-7 development board platform. It meets the requirements SATA2.0 protocol basically.

Relationships of pediatric anthropometrics for CT protocol selection.

PubMed

Phillips, Grace S; Stanescu, Arta-Luana; Alessio, Adam M

2014-07-01

Determining the optimal CT technique to minimize patient radiation exposure while maintaining diagnostic utility requires patient-specific protocols that are based on patient characteristics. This work develops relationships between different anthropometrics and CT image noise to determine appropriate protocol classification schemes. We measured the image noise in 387 CT examinations of pediatric patients (222 boys, 165 girls) of the chest, abdomen, and pelvis and generated mathematic relationships between image noise and patient lateral and anteroposterior dimensions, age, and weight. At the chest level, lateral distance (ld) across the body is strongly correlated with weight (ld = 0.23 × weight + 16.77; R(2) = 0.93) and is less well correlated with age (ld = 1.10 × age + 17.13; R(2) = 0.84). Similar trends were found for anteroposterior dimensions and at the abdomen level. Across all studies, when acquisition-specific parameters are factored out of the noise, the log of image noise was highly correlated with lateral distance (R(2) = 0.72) and weight (R(2) = 0.72) and was less correlated with age (R(2) = 0.62). Following first-order relationships of image noise and scanner technique, plots were formed to show techniques that could achieve matched noise across the pediatric population. Patient lateral distance and weight are essentially equally effective metrics to base maximum technique settings for pediatric patient-specific protocols. These metrics can also be used to help categorize appropriate reference levels for CT technique and size-specific dose estimates across the pediatric population.

An evaluation of in-plane shields during thoracic CT.

PubMed

Foley, S J; McEntee, M F; Rainford, L A

2013-08-01

The object of this study was to compare organ dose and image quality effects of using bismuth and barium vinyl in-plane shields with standard and low tube current thoracic CT protocols. A RANDO phantom was scanned using a 64-slice CT scanner and three different thoracic protocols. Thermoluminescent dosemeters were positioned in six locations to record surface and absorbed breast and lung doses. Image quality was assessed quantitatively using region of interest measurements. Scanning was repeated using bismuth and barium vinyl in-plane shields to cover the breasts and the results were compared with standard and reduced dose protocols. Dose reductions were most evident in the breast, skin and anterior lung when shielding was used, with mean reductions of 34, 33 and 10 % for bismuth and 23, 18 and 11 % for barium, respectively. Bismuth was associated with significant increases in both noise and CT attenuation values for all the three protocols, especially anteriorly and centrally. Barium shielding had a reduced impact on image quality. Reducing the overall tube current reduced doses in all the locations by 20-27 % with similar increases in noise as shielding, without impacting on attenuation values. Reducing the overall tube current best optimises dose with minimal image quality impact. In-plane shields increase noise and attenuation values, while reducing anterior organ doses primarily. Shielding remains a useful optimisation tool in CT and barium is an effective alternative to bismuth especially when image quality is of concern.

A harmonized segmentation protocol for hippocampal and parahippocampal subregions: Why do we need one and what are the key goals?

PubMed

Wisse, Laura E M; Daugherty, Ana M; Olsen, Rosanna K; Berron, David; Carr, Valerie A; Stark, Craig E L; Amaral, Robert S C; Amunts, Katrin; Augustinack, Jean C; Bender, Andrew R; Bernstein, Jeffrey D; Boccardi, Marina; Bocchetta, Martina; Burggren, Alison; Chakravarty, M Mallar; Chupin, Marie; Ekstrom, Arne; de Flores, Robin; Insausti, Ricardo; Kanel, Prabesh; Kedo, Olga; Kennedy, Kristen M; Kerchner, Geoffrey A; LaRocque, Karen F; Liu, Xiuwen; Maass, Anne; Malykhin, Nicolai; Mueller, Susanne G; Ofen, Noa; Palombo, Daniela J; Parekh, Mansi B; Pluta, John B; Pruessner, Jens C; Raz, Naftali; Rodrigue, Karen M; Schoemaker, Dorothee; Shafer, Andrea T; Steve, Trevor A; Suthana, Nanthia; Wang, Lei; Winterburn, Julie L; Yassa, Michael A; Yushkevich, Paul A; la Joie, Renaud

2017-01-01

The advent of high-resolution magnetic resonance imaging (MRI) has enabled in vivo research in a variety of populations and diseases on the structure and function of hippocampal subfields and subdivisions of the parahippocampal gyrus. Because of the many extant and highly discrepant segmentation protocols, comparing results across studies is difficult. To overcome this barrier, the Hippocampal Subfields Group was formed as an international collaboration with the aim of developing a harmonized protocol for manual segmentation of hippocampal and parahippocampal subregions on high-resolution MRI. In this commentary we discuss the goals for this protocol and the associated key challenges involved in its development. These include differences among existing anatomical reference materials, striking the right balance between reliability of measurements and anatomical validity, and the development of a versatile protocol that can be adopted for the study of populations varying in age and health. The commentary outlines these key challenges, as well as the proposed solution of each, with concrete examples from our working plan. Finally, with two examples, we illustrate how the harmonized protocol, once completed, is expected to impact the field by producing measurements that are quantitatively comparable across labs and by facilitating the synthesis of findings across different studies. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Dark blood late enhancement imaging.

PubMed

Kellman, Peter; Xue, Hui; Olivieri, Laura J; Cross, Russell R; Grant, Elena K; Fontana, Marianna; Ugander, Martin; Moon, James C; Hansen, Michael S

2016-11-07

Bright blood late gadolinium enhancement (LGE) imaging typically achieves excellent contrast between infarcted and normal myocardium. However, the contrast between the myocardial infarction (MI) and the blood pool is frequently suboptimal. A large fraction of infarctions caused by coronary artery disease are sub-endocardial and thus adjacent to the blood pool. It is not infrequent that sub-endocardial MIs are difficult to detect or clearly delineate. In this present work, an inversion recovery (IR) T2 preparation was combined with single shot steady state free precession imaging and respiratory motion corrected averaging to achieve dark blood LGE images with good signal to noise ratio while maintaining the desired spatial and temporal resolution. In this manner, imaging was conducted free-breathing, which has benefits for image quality, patient comfort, and clinical workflow in both adults and children. Furthermore, by using a phase sensitive inversion recovery reconstruction the blood signal may be made darker than the myocardium (i.e., negative signal values) thereby providing contrast between the blood and both the MI and remote myocardium. In the proposed approach, a single T1-map scout was used to measure the myocardial and blood T1 using a MOdified Look-Locker Inversion recovery (MOLLI) protocol and all protocol parameters were automatically calculated from these values within the sequence thereby simplifying the user interface. The contrast to noise ratio (CNR) between MI and remote myocardium was measured in n = 30 subjects with subendocardial MI using both bright blood and dark blood protocols. The CNR for the dark blood protocol had a 13 % loss compared to the bright blood protocol. The CNR between the MI and blood pool was positive for all dark blood cases, and was negative in 63 % of the bright blood cases. The conspicuity of subendocardial fibrosis and MI was greatly improved by dark blood (DB) PSIR as well as the delineation of the subendocardial border. Free-breathing, dark blood PSIR LGE imaging was demonstrated to improve the visualization of subendocardial MI and fibrosis in cases with low contrast with adjacent blood pool. The proposed method also improves visualization of thin walled fibrous structures such as atrial walls and valves, as well as papillary muscles.

Systems Imaging of the Immune Synapse.

PubMed

Ambler, Rachel; Ruan, Xiangtao; Murphy, Robert F; Wülfing, Christoph

2017-01-01

Three-dimensional live cell imaging of the interaction of T cells with antigen-presenting cells (APCs) visualizes the subcellular distributions of signaling intermediates during T cell activation at thousands of resolved positions within a cell. These information-rich maps of local protein concentrations are a valuable resource in understanding T cell signaling. Here, we describe a protocol for the efficient acquisition of such imaging data and their computational processing to create four-dimensional maps of local concentrations. This protocol allows quantitative analysis of T cell signaling as it occurs inside live cells with resolution in time and space across thousands of cells.

Localization-based super-resolution imaging of cellular structures.

PubMed

Kanchanawong, Pakorn; Waterman, Clare M

2013-01-01

Fluorescence microscopy allows direct visualization of fluorescently tagged proteins within cells. However, the spatial resolution of conventional fluorescence microscopes is limited by diffraction to ~250 nm, prompting the development of super-resolution microscopy which offers resolution approaching the scale of single proteins, i.e., ~20 nm. Here, we describe protocols for single molecule localization-based super-resolution imaging, using focal adhesion proteins as an example and employing either photoswitchable fluorophores or photoactivatable fluorescent proteins. These protocols should also be easily adaptable to imaging a broad array of macromolecular assemblies in cells whose components can be fluorescently tagged and assemble into high density structures.

75 FR 63841 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-18

...; [email protected] . Signal-to-Noise Enhancement in Imaging Applications Using a Time-Series of Images... reduction in imaging applications that use a time-series of images. In one embodiment of the invention, a time-series of images is acquired using a same imaging protocol of the same subject area, but the...

Large-scale image region documentation for fully automated image biomarker algorithm development and evaluation.

PubMed

Reeves, Anthony P; Xie, Yiting; Liu, Shuang

2017-04-01

With the advent of fully automated image analysis and modern machine learning methods, there is a need for very large image datasets having documented segmentations for both computer algorithm training and evaluation. This paper presents a method and implementation for facilitating such datasets that addresses the critical issue of size scaling for algorithm validation and evaluation; current evaluation methods that are usually used in academic studies do not scale to large datasets. This method includes protocols for the documentation of many regions in very large image datasets; the documentation may be incrementally updated by new image data and by improved algorithm outcomes. This method has been used for 5 years in the context of chest health biomarkers from low-dose chest CT images that are now being used with increasing frequency in lung cancer screening practice. The lung scans are segmented into over 100 different anatomical regions, and the method has been applied to a dataset of over 20,000 chest CT images. Using this framework, the computer algorithms have been developed to achieve over 90% acceptable image segmentation on the complete dataset.

Nanogels as imaging agents for modalities spanning the electromagnetic spectrum.

PubMed

Chan, Minnie; Almutairi, Adah

2016-01-21

In the past few decades, advances in imaging equipment and protocols have expanded the role of imaging in in vivo diagnosis and disease management, especially in cancer. Traditional imaging agents have rapid clearance and low specificity for disease detection. To improve accuracy in disease identification, localization and assessment, novel nanomaterials are frequently explored as imaging agents to achieve high detection specificity and sensitivity. A promising material for this purpose are hydrogel nanoparticles, whose high hydrophilicity, biocompatibility, and tunable size in the nanometer range make them ideal for imaging. These nanogels (10 to 200 nm) can circumvent uptake by the reticuloendothelial system, allowing longer circulation times than small molecules. In addition, their size/surface properties can be further tailored to optimize their pharmacokinetics for imaging of a particular disease. Herein, we provide a comprehensive review of nanogels as imaging agents in various modalities with sources of signal spanning the electromagnetic spectrum, including MRI, NIR, UV-vis, and PET. Many materials and formulation methods will be reviewed to highlight the versatility of nanogels as imaging agents.

Improved spatial coverage for brain 3D PRESS MRSI by automatic placement of outer-volume suppression saturation bands.

PubMed

Ozhinsky, Eugene; Vigneron, Daniel B; Nelson, Sarah J

2011-04-01

To develop a technique for optimizing coverage of brain 3D (1) H magnetic resonance spectroscopic imaging (MRSI) by automatic placement of outer-volume suppression (OVS) saturation bands (sat bands) and to compare the performance for point-resolved spectroscopic sequence (PRESS) MRSI protocols with manual and automatic placement of sat bands. The automated OVS procedure includes the acquisition of anatomic images from the head, obtaining brain and lipid tissue maps, calculating optimal sat band placement, and then using those optimized parameters during the MRSI acquisition. The data were analyzed to quantify brain coverage volume and data quality. 3D PRESS MRSI data were acquired from three healthy volunteers and 29 patients using protocols that included either manual or automatic sat band placement. On average, the automatic sat band placement allowed the acquisition of PRESS MRSI data from 2.7 times larger brain volumes than the conventional method while maintaining data quality. The technique developed helps solve two of the most significant problems with brain PRESS MRSI acquisitions: limited brain coverage and difficulty in prescription. This new method will facilitate routine clinical brain 3D MRSI exams and will be important for performing serial evaluation of response to therapy in patients with brain tumors and other neurological diseases. Copyright © 2011 Wiley-Liss, Inc.

Use of sonic tomography to detect and quantify wood decay in living trees1

PubMed Central

Gilbert, Gregory S.; Ballesteros, Javier O.; Barrios-Rodriguez, Cesar A.; Bonadies, Ernesto F.; Cedeño-Sánchez, Marjorie L.; Fossatti-Caballero, Nohely J.; Trejos-Rodríguez, Mariam M.; Pérez-Suñiga, José Moises; Holub-Young, Katharine S.; Henn, Laura A. W.; Thompson, Jennifer B.; García-López, Cesar G.; Romo, Amanda C.; Johnston, Daniel C.; Barrick, Pablo P.; Jordan, Fulvia A.; Hershcovich, Shiran; Russo, Natalie; Sánchez, Juan David; Fábrega, Juan Pablo; Lumpkin, Raleigh; McWilliams, Hunter A.; Chester, Kathleen N.; Burgos, Alana C.; Wong, E. Beatriz; Diab, Jonathan H.; Renteria, Sonia A.; Harrower, Jennifer T.; Hooton, Douglas A.; Glenn, Travis C.; Faircloth, Brant C.; Hubbell, Stephen P.

2016-01-01

Premise of the study: Field methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes. Methods and Results: Living trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness. Conclusions: Sonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees. PMID:28101433

Impact of Image Filters and Observations Parameters in CBCT for Identification of Mandibular Osteolytic Lesions

PubMed Central

Monteiro, Bruna Moraes; Nobrega Filho, Denys Silveira; Lopes, Patrícia de Medeiros Loureiro; de Sales, Marcelo Augusto Oliveira

2012-01-01

The aim of this study was to analyze the influence of filters (algorithms) to improve the image of Cone Beam Computed Tomography (CBCT) in diagnosis of osteolytic lesions of the mandible, in order to establish the protocols for viewing images more suitable for CBCT diagnostics. 15 dry mandibles in which perforations were performed, simulating lesions, were submitted to CBCT examination. Two examiners analyzed the images, using filters to improve image Hard, Normal, and Very Sharp, contained in the iCAT Vision software, and protocols for assessment: axial; sagittal and coronal; and axial, sagittal and coronal planes simultaneously (MPR), on two occasions. The sensitivity and specificity (validity) of the cone beam computed tomography (CBCT) have been demonstrated as the values achieved were above 75% for sensitivity and above 85% for specificity, reaching around 95.5% of sensitivity and 99% of specificity when we used the appropriate observation protocol. It was concluded that the use of filters (algorithms) to improve the CBCT image influences the diagnosis, due to the fact that all measured values were correspondingly higher when it was used the filter Very Sharp, which justifies its use for clinical activities, followed by Hard and Normal filters, in order of decreasing values. PMID:22956955

Impact of Image Filters and Observations Parameters in CBCT for Identification of Mandibular Osteolytic Lesions.

PubMed

Monteiro, Bruna Moraes; Nobrega Filho, Denys Silveira; Lopes, Patrícia de Medeiros Loureiro; de Sales, Marcelo Augusto Oliveira

2012-01-01

The aim of this study was to analyze the influence of filters (algorithms) to improve the image of Cone Beam Computed Tomography (CBCT) in diagnosis of osteolytic lesions of the mandible, in order to establish the protocols for viewing images more suitable for CBCT diagnostics. 15 dry mandibles in which perforations were performed, simulating lesions, were submitted to CBCT examination. Two examiners analyzed the images, using filters to improve image Hard, Normal, and Very Sharp, contained in the iCAT Vision software, and protocols for assessment: axial; sagittal and coronal; and axial, sagittal and coronal planes simultaneously (MPR), on two occasions. The sensitivity and specificity (validity) of the cone beam computed tomography (CBCT) have been demonstrated as the values achieved were above 75% for sensitivity and above 85% for specificity, reaching around 95.5% of sensitivity and 99% of specificity when we used the appropriate observation protocol. It was concluded that the use of filters (algorithms) to improve the CBCT image influences the diagnosis, due to the fact that all measured values were correspondingly higher when it was used the filter Very Sharp, which justifies its use for clinical activities, followed by Hard and Normal filters, in order of decreasing values.

Anatomic study of the canine stifle using low-field magnetic resonance imaging (MRI) and MRI arthrography.

PubMed

Pujol, Esteban; Van Bree, Henri; Cauzinille, Laurent; Poncet, Cyrill; Gielen, Ingrid; Bouvy, Bernard

2011-06-01

To investigate the use of low-field magnetic resonance imaging (MRI) and MR arthrography in normal canine stifles and to compare MRI images to gross dissection. Descriptive study. Adult canine pelvic limbs (n=17). Stifle joints from 12 dogs were examined by orthopedic and radiographic examination, synovial fluid analysis, and MRI performed using a 0.2 T system. Limbs 1 to 7 were used to develop the MR and MR arthrography imaging protocol. Limbs 8-17 were studied with the developed MR and MR arthrography protocol and by gross dissection. Three sequences were obtained: T1-weighted spin echo (SE) in sagittal, dorsal, and transverse plane; T2-weighted SE in sagittal plane and T1-gradient echo in sagittal plane. Specific bony and soft tissue structures were easily identifiable with the exception of articular cartilage. The cranial and caudal cruciate ligaments were identified. Medial and lateral menisci were seen as wedge-shaped hypointense areas. MR arthrography permitted further delineation of specific structures. MR images corresponded with gross dissection morphology. With the exception of poor delineation of articular cartilage, a low-field MRI and MR arthrography protocol provides images of adequate quality to assess the normal canine stifle joint. © Copyright 2011 by The American College of Veterinary Surgeons.

The role of digital imaging and communications in medicine in an evolving healthcare computing environment: the model is the message.

PubMed

Bidgood, W D; alSafadi, Y; Tucker, M; Prior, F; Hagan, G; Mattison, J E

1998-02-01

The decision to use Digital Imaging and Communications in Medicine (DICOM), Health Level 7 (HL7), a common object broker such as the Common Object Request Brokering Architecture (CORBA) or ActiveX (Microsoft Corp, Redmond, WA) or any other protocol for the transfer of DICOM data depends on the requirements of a particular implementation. The selection of protocol is independent of the information model. Our goal as message standards developers is to design a data interchange infrastructure that will faithfully convey the computer-based patient record and make it available to authorized health care providers when and where it is needed for patient care. DICOM accurately and expressively represents the clinically significant properties of images and the semantics of image-related information. The DICOM data model is small and well-defined. The model can be expressed in Standard Generalized Markup Language (SGML) or Object Management Group Interface Definition Language or other common syntax-and can be implemented using any reliable communications protocol. Therefore our opinion is that the DICOM semantic data model should serve as the basis for a logically equivalent set of specifications in HL7, CORBA, ActiveX, and SGML for the interchange of biomedical images and image-related information.

Quantitative Comparison of 21 Protocols for Labeling Hippocampal Subfields and Parahippocampal Subregions in In Vivo MRI: Towards a Harmonized Segmentation Protocol

PubMed Central

Yushkevich, Paul A.; Amaral, Robert S. C.; Augustinack, Jean C.; Bender, Andrew R.; Bernstein, Jeffrey D.; Boccardi, Marina; Bocchetta, Martina; Burggren, Alison C.; Carr, Valerie A.; Chakravarty, M. Mallar; Chetelat, Gael; Daugherty, Ana M.; Davachi, Lila; Ding, Song-Lin; Ekstrom, Arne; Geerlings, Mirjam I.; Hassan, Abdul; Huang, Yushan; Iglesias, Eugenio; La Joie, Renaud; Kerchner, Geoffrey A.; LaRocque, Karen F.; Libby, Laura A.; Malykhin, Nikolai; Mueller, Susanne G.; Olsen, Rosanna K.; Palombo, Daniela J.; Parekh, Mansi B; Pluta, John B.; Preston, Alison R.; Pruessner, Jens C.; Ranganath, Charan; Raz, Naftali; Schlichting, Margaret L.; Schoemaker, Dorothee; Singh, Sachi; Stark, Craig E. L.; Suthana, Nanthia; Tompary, Alexa; Turowski, Marta M.; Van Leemput, Koen; Wagner, Anthony D.; Wang, Lei; Winterburn, Julie L.; Wisse, Laura E.M.; Yassa, Michael A.; Zeineh, Michael M.

2015-01-01

OBJECTIVE An increasing number of human in vivo magnetic resonance imaging (MRI) studies have focused on examining the structure and function of the subfields of the hippocampal formation (the dentate gyrus, CA fields 1–3, and the subiculum) and subregions of the parahippocampal gyrus (entorhinal, perirhinal, and parahippocampal cortices). The ability to interpret the results of such studies and to relate them to each other would be improved if a common standard existed for labeling hippocampal subfields and parahippocampal subregions. Currently, research groups label different subsets of structures and use different rules, landmarks, and cues to define their anatomical extents. This paper characterizes, both qualitatively and quantitatively, the variability in the existing manual segmentation protocols for labeling hippocampal and parahippocampal substructures in MRI, with the goal of guiding subsequent work on developing a harmonized substructure segmentation protocol. METHOD MRI scans of a single healthy adult human subject were acquired both at 3 Tesla and 7 Tesla. Representatives from 21 research groups applied their respective manual segmentation protocols to the MRI modalities of their choice. The resulting set of 21 segmentations was analyzed in a common anatomical space to quantify similarity and identify areas of agreement. RESULTS The differences between the 21 protocols include the region within which segmentation is performed, the set of anatomical labels used, and the extents of specific anatomical labels. The greatest overall disagreement among the protocols is at the CA1/subiculum boundary, and disagreement across all structures is greatest in the anterior portion of the hippocampal formation relative to the body and tail. CONCLUSIONS The combined examination of the 21 protocols in the same dataset suggests possible strategies towards developing a harmonized subfield segmentation protocol and facilitates comparison between published studies. PMID:25596463

ACQ4: an open-source software platform for data acquisition and analysis in neurophysiology research

PubMed Central

Campagnola, Luke; Kratz, Megan B.; Manis, Paul B.

2014-01-01

The complexity of modern neurophysiology experiments requires specialized software to coordinate multiple acquisition devices and analyze the collected data. We have developed ACQ4, an open-source software platform for performing data acquisition and analysis in experimental neurophysiology. This software integrates the tasks of acquiring, managing, and analyzing experimental data. ACQ4 has been used primarily for standard patch-clamp electrophysiology, laser scanning photostimulation, multiphoton microscopy, intrinsic imaging, and calcium imaging. The system is highly modular, which facilitates the addition of new devices and functionality. The modules included with ACQ4 provide for rapid construction of acquisition protocols, live video display, and customizable analysis tools. Position-aware data collection allows automated construction of image mosaics and registration of images with 3-dimensional anatomical atlases. ACQ4 uses free and open-source tools including Python, NumPy/SciPy for numerical computation, PyQt for the user interface, and PyQtGraph for scientific graphics. Supported hardware includes cameras, patch clamp amplifiers, scanning mirrors, lasers, shutters, Pockels cells, motorized stages, and more. ACQ4 is available for download at http://www.acq4.org. PMID:24523692

Thick tissue diffusion model with binding to optimize topical staining in fluorescence breast cancer margin imaging

NASA Astrophysics Data System (ADS)

Xu, Xiaochun; Kang, Soyoung; Navarro-Comes, Eric; Wang, Yu; Liu, Jonathan T. C.; Tichauer, Kenneth M.

2018-03-01

Intraoperative tumor/surgical margin assessment is required to achieve higher tumor resection rate in breast-conserving surgery. Though current histology provides incomparable accuracy in margin assessment, thin tissue sectioning and the limited field of view of microscopy makes histology too time-consuming for intraoperative applications. If thick tissue, wide-field imaging can provide an acceptable assessment of tumor cells at the surface of resected tissues, an intraoperative protocol can be developed to guide the surgery and provide immediate feedback for surgeons. Topical staining of margins with cancer-targeted molecular imaging agents has the potential to provide the sensitivity needed to see microscopic cancer on a wide-field image; however, diffusion and nonspecific retention of imaging agents in thick tissue can significantly diminish tumor contrast with conventional methods. Here, we present a mathematical model to accurately simulate nonspecific retention, binding, and diffusion of imaging agents in thick tissue topical staining to guide and optimize future thick tissue staining and imaging protocol. In order to verify the accuracy and applicability of the model, diffusion profiles of cancer targeted and untargeted (control) nanoparticles at different staining times in A431 tumor xenografts were acquired for model comparison and tuning. The initial findings suggest the existence of nonspecific retention in the tissue, especially at the tissue surface. The simulator can be used to compare the effect of nonspecific retention, receptor binding and diffusion under various conditions (tissue type, imaging agent) and provides optimal staining and imaging protocols for targeted and control imaging agent.

Application of a newly developed software program for image quality assessment in cone-beam computed tomography.

PubMed

de Oliveira, Marcus Vinicius Linhares; Santos, António Carvalho; Paulo, Graciano; Campos, Paulo Sergio Flores; Santos, Joana

2017-06-01

The purpose of this study was to apply a newly developed free software program, at low cost and with minimal time, to evaluate the quality of dental and maxillofacial cone-beam computed tomography (CBCT) images. A polymethyl methacrylate (PMMA) phantom, CQP-IFBA, was scanned in 3 CBCT units with 7 protocols. A macro program was developed, using the free software ImageJ, to automatically evaluate the image quality parameters. The image quality evaluation was based on 8 parameters: uniformity, the signal-to-noise ratio (SNR), noise, the contrast-to-noise ratio (CNR), spatial resolution, the artifact index, geometric accuracy, and low-contrast resolution. The image uniformity and noise depended on the protocol that was applied. Regarding the CNR, high-density structures were more sensitive to the effect of scanning parameters. There were no significant differences between SNR and CNR in centered and peripheral objects. The geometric accuracy assessment showed that all the distance measurements were lower than the real values. Low-contrast resolution was influenced by the scanning parameters, and the 1-mm rod present in the phantom was not depicted in any of the 3 CBCT units. Smaller voxel sizes presented higher spatial resolution. There were no significant differences among the protocols regarding artifact presence. This software package provided a fast, low-cost, and feasible method for the evaluation of image quality parameters in CBCT.

Efficiency Improvement in a Busy Radiology Practice: Determination of Musculoskeletal Magnetic Resonance Imaging Protocol Using Deep-Learning Convolutional Neural Networks.

PubMed

Lee, Young Han

2018-04-04

The purposes of this study are to evaluate the feasibility of protocol determination with a convolutional neural networks (CNN) classifier based on short-text classification and to evaluate the agreements by comparing protocols determined by CNN with those determined by musculoskeletal radiologists. Following institutional review board approval, the database of a hospital information system (HIS) was queried for lists of MRI examinations, referring department, patient age, and patient gender. These were exported to a local workstation for analyses: 5258 and 1018 consecutive musculoskeletal MRI examinations were used for the training and test datasets, respectively. The subjects for pre-processing were routine or tumor protocols and the contents were word combinations of the referring department, region, contrast media (or not), gender, and age. The CNN Embedded vector classifier was used with Word2Vec Google news vectors. The test set was tested with each classification model and results were output as routine or tumor protocols. The CNN determinations were evaluated using the receiver operating characteristic (ROC) curves. The accuracies were evaluated by a radiologist-confirmed protocol as the reference protocols. The optimal cut-off values for protocol determination between routine protocols and tumor protocols was 0.5067 with a sensitivity of 92.10%, a specificity of 95.76%, and an area under curve (AUC) of 0.977. The overall accuracy was 94.2% for the ConvNet model. All MRI protocols were correct in the pelvic bone, upper arm, wrist, and lower leg MRIs. Deep-learning-based convolutional neural networks were clinically utilized to determine musculoskeletal MRI protocols. CNN-based text learning and applications could be extended to other radiologic tasks besides image interpretations, improving the work performance of the radiologist.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Persson, Mats, E-mail: mats.persson@mi.physics.kth

Purpose: The highest photon fluence rate that a computed tomography (CT) detector must be able to measure is an important parameter. The authors calculate the maximum transmitted fluence rate in a commercial CT scanner as a function of patient size for standard head, chest, and abdomen protocols. Methods: The authors scanned an anthropomorphic phantom (Kyoto Kagaku PBU-60) with the reference CT protocols provided by AAPM on a GE LightSpeed VCT scanner and noted the tube current applied with the tube current modulation (TCM) system. By rescaling this tube current using published measurements on the tube current modulation of a GEmore » scanner [N. Keat, “CT scanner automatic exposure control systems,” MHRA Evaluation Report 05016, ImPACT, London, UK, 2005], the authors could estimate the tube current that these protocols would have resulted in for other patient sizes. An ECG gated chest protocol was also simulated. Using measured dose rate profiles along the bowtie filters, the authors simulated imaging of anonymized patient images with a range of sizes on a GE VCT scanner and calculated the maximum transmitted fluence rate. In addition, the 99th and the 95th percentiles of the transmitted fluence rate distribution behind the patient are calculated and the effect of omitting projection lines passing just below the skin line is investigated. Results: The highest transmitted fluence rates on the detector for the AAPM reference protocols with centered patients are found for head images and for intermediate-sized chest images, both with a maximum of 3.4 ⋅ 10{sup 8} mm{sup −2} s{sup −1}, at 949 mm distance from the source. Miscentering the head by 50 mm downward increases the maximum transmitted fluence rate to 5.7 ⋅ 10{sup 8} mm{sup −2} s{sup −1}. The ECG gated chest protocol gives fluence rates up to 2.3 ⋅ 10{sup 8} − 3.6 ⋅ 10{sup 8} mm{sup −2} s{sup −1} depending on miscentering. Conclusions: The fluence rate on a CT detector reaches 3 ⋅ 10{sup 8} − 6 ⋅ 10{sup 8} mm{sup −2} s{sup −1} in standard imaging protocols, with the highest rates occurring for ECG gated chest and miscentered head scans. These results will be useful to developers of CT detectors, in particular photon counting detectors.« less

SU-F-J-48: Effect of Scan Length On Magnitude of Imaging Dose in KV CBCT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deshpande, S; Naidu, S; Sutar, A

Purpose: To study effect of scan length on magnitude of imaging dose deposition in Varian kV CBCT for head & neck and pelvis CBCT. Methods: To study effect of scan length we measured imaging dose at depth of 8 cm for head and neck Cone Beam Computed Tomography (CBCT) acquisition ( X ray beam energy is used 100kV and 200 degree of gantry rotation) and at 16 cm depth for pelvis CBCT acquisition ( X ray beam energy used is 125 kV and 360 degree of gantry rotation) in specially designed phantom. We used farmer chamber which was calibrated inmore » kV X ray range for measurements .Dose was measured with default field size, and reducing field size along y direction to 10 cm and 5 cm. Results: As the energy of the beam decreases the scattered radiation increases and this contributes significantly to the dose deposited in the patient. By reducing the scan length to 10 Cm from default 20.6 cm we found a dose reduction of 14% for head and neck CBCT protocol and a reduction of 26% for pelvis CBCT protocol. Similarly for a scan length of 5cm compared to default the dose reduction in head and neck CBCT protocol is 36% while in the pelvis CBCT protocol the dose reduction is 50%. Conclusion: By limiting the scan length we can control the scatter radiation generated and hence the dose to the patient. However the variation in dose reduction for same length used in two protocols is because of the scan geometry. The pelvis CBCT protocol uses a full rotation and head and neck CBCT protocol uses partial rotation.« less

RADIOLOGY EDUCATION: A PILOT STUDY TO ASSESS KNOWLEDGE OF MEDICAL STUDENTS REGARDING IMAGING IN TRAUMA.

PubMed

Siddiqui, Saad; Saeed, Muhammad Anwar; Shah, Noreen; Nadeem, Naila

2015-01-01

Trauma remains one of the most frequent presentations in emergency departments. Imaging has established role in setting of acute trauma with ability to identify potentially fatal conditions. Adequate knowledge of health professionals regarding trauma imaging is vital for improved healthcare. In this work we try to assess knowledge of medical students regarding imaging in trauma as well as identify most effective way of imparting radiology education. This cross-sectional pilot study was conducted at Aga Khan University Medical College & Khyber Girls Medical College, to assess knowledge of medical students regarding imaging protocols practiced in initial management of trauma patients. Only 40 & 20% respectively were able to identify radiographs included in trauma series. Very few had knowledge of correct indication for Focused abdominal sonography in trauma. Clinical radiology rotation was reported as best way of learning radiology. Change in curricula & restructuring of clinical radiology rotation structure is needed to improve knowledge regarding Trauma imaging.

Optimization of a shorter variable-acquisition time for legs to achieve true whole-body PET/CT images.

PubMed

Umeda, Takuro; Miwa, Kenta; Murata, Taisuke; Miyaji, Noriaki; Wagatsuma, Kei; Motegi, Kazuki; Terauchi, Takashi; Koizumi, Mitsuru

2017-12-01

The present study aimed to qualitatively and quantitatively evaluate PET images as a function of acquisition time for various leg sizes, and to optimize a shorter variable-acquisition time protocol for legs to achieve better qualitative and quantitative accuracy of true whole-body PET/CT images. The diameters of legs to be modeled as phantoms were defined based on data derived from 53 patients. This study analyzed PET images of a NEMA phantom and three plastic bottle phantoms (diameter, 5.68, 8.54 and 10.7 cm) that simulated the human body and legs, respectively. The phantoms comprised two spheres (diameters, 10 and 17 mm) containing fluorine-18 fluorodeoxyglucose solution with sphere-to-background ratios of 4 at a background radioactivity level of 2.65 kBq/mL. All PET data were reconstructed with acquisition times ranging from 10 to 180, and 1200 s. We visually evaluated image quality and determined the coefficient of variance (CV) of the background, contrast and the quantitative %error of the hot spheres, and then determined two shorter variable-acquisition protocols for legs. Lesion detectability and quantitative accuracy determined based on maximum standardized uptake values (SUV max ) in PET images of a patient using the proposed protocols were also evaluated. A larger phantom and a shorter acquisition time resulted in increased background noise on images and decreased the contrast in hot spheres. A visual score of ≥ 1.5 was obtained when the acquisition time was ≥ 30 s for three leg phantoms, and ≥ 120 s for the NEMA phantom. The quantitative %errors of the 10- and 17-mm spheres in the leg phantoms were ± 15 and ± 10%, respectively, in PET images with a high CV (scan < 30 s). The mean SUV max of three lesions using the current fixed-acquisition and two proposed variable-acquisition time protocols in the clinical study were 3.1, 3.1 and 3.2, respectively, which did not significantly differ. Leg acquisition time per bed position of even 30-90 s allows axial equalization, uniform image noise and a maximum ± 15% quantitative accuracy for the smallest lesion. The overall acquisition time was reduced by 23-42% using the proposed shorter variable than the current fixed-acquisition time for imaging legs, indicating that this is a useful and practical protocol for routine qualitative and quantitative PET/CT assessment in the clinical setting.

The Primer for Sports Medicine Professionals on Imaging

PubMed Central

Farshad-Amacker, Nadja A.; Jain Palrecha, Sapna; Farshad, Mazda

2013-01-01

Because of its inherent superior soft tissue contrast and lack of ionizing radiation, magnetic resonance imaging (MRI) is highly suited to study the complex anatomy of the shoulder joint, particularly when assessing the relatively high incidence of shoulder injuries in young, athletic patients. This review aims to serve as a primer for understanding shoulder MRI in an algorithmical approach, including MRI protocol and technique, normal anatomy and anatomical variations of the shoulder, pathologic conditions of the rotator cuff tendons and muscles, the long head of the biceps tendon, shoulder impingement, labral and glenohumeral ligament pathology, MR findings in shoulder instability, adhesive capsulitis, and osteoarthritis. PMID:24381700

Image quality and radiation reduction of 320-row area detector CT coronary angiography with optimal tube voltage selection and an automatic exposure control system: comparison with body mass index-adapted protocol.

PubMed

Lim, Jiyeon; Park, Eun-Ah; Lee, Whal; Shim, Hackjoon; Chung, Jin Wook

2015-06-01

To assess the image quality and radiation exposure of 320-row area detector computed tomography (320-ADCT) coronary angiography with optimal tube voltage selection with the guidance of an automatic exposure control system in comparison with a body mass index (BMI)-adapted protocol. Twenty-two patients (study group) underwent 320-ADCT coronary angiography using an automatic exposure control system with the target standard deviation value of 33 as the image quality index and the lowest possible tube voltage. For comparison, a sex- and BMI-matched group (control group, n = 22) using a BMI-adapted protocol was established. Images of both groups were reconstructed by an iterative reconstruction algorithm. For objective evaluation of the image quality, image noise, vessel density, signal to noise ratio (SNR), and contrast to noise ratio (CNR) were measured. Two blinded readers then subjectively graded the image quality using a four-point scale (1: nondiagnostic to 4: excellent). Radiation exposure was also measured. Although the study group tended to show higher image noise (14.1 ± 3.6 vs. 9.3 ± 2.2 HU, P = 0.111) and higher vessel density (665.5 ± 161 vs. 498 ± 143 HU, P = 0.430) than the control group, the differences were not significant. There was no significant difference between the two groups for SNR (52.5 ± 19.2 vs. 60.6 ± 21.8, P = 0.729), CNR (57.0 ± 19.8 vs. 67.8 ± 23.3, P = 0.531), or subjective image quality scores (3.47 ± 0.55 vs. 3.59 ± 0.56, P = 0.960). However, radiation exposure was significantly reduced by 42 % in the study group (1.9 ± 0.8 vs. 3.6 ± 0.4 mSv, P = 0.003). Optimal tube voltage selection with the guidance of an automatic exposure control system in 320-ADCT coronary angiography allows substantial radiation reduction without significant impairment of image quality, compared to the results obtained using a BMI-based protocol.

Chest CT in children: anesthesia and atelectasis.

PubMed

Newman, Beverley; Krane, Elliot J; Gawande, Rakhee; Holmes, Tyson H; Robinson, Terry E

2014-02-01

There has been an increasing tendency for anesthesiologists to be responsible for providing sedation or anesthesia during chest CT imaging in young children. Anesthesia-related atelectasis noted on chest CT imaging has proven to be a common and troublesome problem, affecting image quality and diagnostic sensitivity. To evaluate the safety and effectiveness of a standardized anesthesia, lung recruitment, controlled-ventilation technique developed at our institution to prevent atelectasis for chest CT imaging in young children. Fifty-six chest CT scans were obtained in 42 children using a research-based intubation, lung recruitment and controlled-ventilation CT scanning protocol. These studies were compared with 70 non-protocolized chest CT scans under anesthesia taken from 18 of the same children, who were tested at different times, without the specific lung recruitment and controlled-ventilation technique. Two radiology readers scored all inspiratory chest CT scans for overall CT quality and atelectasis. Detailed cardiorespiratory parameters were evaluated at baseline, and during recruitment and inspiratory imaging on 21 controlled-ventilation cases and 8 control cases. Significant differences were noted between groups for both quality and atelectasis scores with optimal scoring demonstrated in the controlled-ventilation cases where 70% were rated very good to excellent quality scans compared with only 24% of non-protocol cases. There was no or minimal atelectasis in 48% of the controlled ventilation cases compared to 51% of non-protocol cases with segmental, multisegmental or lobar atelectasis present. No significant difference in cardiorespiratory parameters was found between controlled ventilation and other chest CT cases and no procedure-related adverse events occurred. Controlled-ventilation infant CT scanning under general anesthesia, utilizing intubation and recruitment maneuvers followed by chest CT scans, appears to be a safe and effective method to obtain reliable and reproducible high-quality, motion-free chest CT images in children.