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Sample records for enhancement mri distinguishes

  1. Distinguishing intrahepatic cholangiocarcinoma from poorly differentiated hepatocellular carcinoma using precontrast and gadoxetic acid-enhanced MRI

    PubMed Central

    Asayama, Yoshiki; Nishie, Akihiro; Ishigami, Kousei; Ushijima, Yasuhiro; Takayama, Yukihisa; Fujita, Nobuhiro; Kubo, Yuichiro; Aishima, Shinichi; Shirabe, Ken; Yoshiura, Takashi; Honda, Hiroshi

    2015-01-01

    PURPOSE We aimed to gain further insight in magnetic resonance imaging characteristics of mass-forming intrahepatic cholangiocarcinoma (mICC), its enhancement pattern with gadoxetic acid contrast agent, and distinction from poorly differentiated hepatocellular carcinoma (pHCC). METHODS Fourteen mICC and 22 pHCC nodules were included in this study. Two observers recorded the tumor shape, intratumoral hemorrhage, fat on chemical shift imaging, signal intensity at the center of the tumor on T2-weighted image, fibrous capsule, enhancement pattern on arterial phase of dynamic study, late enhancement three minutes after contrast injection (dynamic late phase), contrast uptake on hepatobiliary phase, apparent diffusion coefficient, vascular invasion, and intrahepatic metastasis. RESULTS Late enhancement was more common in mICC (n=10, 71%) than in pHCC (n=3, 14%) (P < 0.001). A fat component was observed in 11 pHCC cases (50%) versus none of mICC cases (P = 0.002). Fibrous capsule was observed in 13 pHCC cases (59%) versus none of mICC cases (P < 0.001). On T2-weighted images a hypointense area was seen at the center of the tumor in 43% of mICC (6/14) and 9% of pHCC (2/22) cases (P = 0.018). Other parameters were not significantly different between the two types of nodules. CONCLUSION The absence of fat and fibrous capsule, and presence of enhancement at three minutes appear to be most characteristic for mICC and may help its differentiation from pHCC. PMID:25698097

  2. On the distinguishability of HRF models in fMRI

    PubMed Central

    Rosa, Paulo N.; Figueiredo, Patricia; Silvestre, Carlos J.

    2015-01-01

    Modeling the Hemodynamic Response Function (HRF) is a critical step in fMRI studies of brain activity, and it is often desirable to estimate HRF parameters with physiological interpretability. A biophysically informed model of the HRF can be described by a non-linear time-invariant dynamic system. However, the identification of this dynamic system may leave much uncertainty on the exact values of the parameters. Moreover, the high noise levels in the data may hinder the model estimation task. In this context, the estimation of the HRF may be seen as a problem of model falsification or invalidation, where we are interested in distinguishing among a set of eligible models of dynamic systems. Here, we propose a systematic tool to determine the distinguishability among a set of physiologically plausible HRF models. The concept of absolutely input-distinguishable systems is introduced and applied to a biophysically informed HRF model, by exploiting the structure of the underlying non-linear dynamic system. A strategy to model uncertainty in the input time-delay and magnitude is developed and its impact on the distinguishability of two physiologically plausible HRF models is assessed, in terms of the maximum noise amplitude above which it is not possible to guarantee the falsification of one model in relation to another. Finally, a methodology is proposed for the choice of the input sequence, or experimental paradigm, that maximizes the distinguishability of the HRF models under investigation. The proposed approach may be used to evaluate the performance of HRF model estimation techniques from fMRI data. PMID:26106322

  3. Distinguishing Grammatical Constructions with fMRI Pattern Analysis

    ERIC Educational Resources Information Center

    Allen, Kachina; Pereira, Francisco; Botvinick, Matthew; Goldberg, Adele E.

    2012-01-01

    All linguistic and psycholinguistic theories aim to provide psychologically valid analyses of particular grammatical patterns and the relationships that hold among them. Until recently, no tools were available to distinguish neural correlates of particular grammatical constructions that shared the same content words, propositional meaning, and…

  4. Texture descriptors to distinguish radiation necrosis from recurrent brain tumors on multi-parametric MRI

    NASA Astrophysics Data System (ADS)

    Tiwari, Pallavi; Prasanna, Prateek; Rogers, Lisa; Wolansky, Leo; Badve, Chaitra; Sloan, Andrew; Cohen, Mark; Madabhushi, Anant

    2014-03-01

    Di erentiating radiation necrosis (a radiation induced treatment e ect) from recurrent brain tumors (rBT) is currently one of the most clinically challenging problems in care and management of brain tumor (BT) patients. Both radiation necrosis (RN), and rBT exhibit similar morphological appearance on standard MRI making non-invasive diagnosis extremely challenging for clinicians, with surgical intervention being the only course for obtaining de nitive ground truth". Recent studies have reported that the underlying biological pathways de n- ing RN and rBT are fundamentally di erent. This strongly suggests that there might be phenotypic di erences and hence cues on multi-parametric MRI, that can distinguish between the two pathologies. One challenge is that these di erences, if they exist, might be too subtle to distinguish by the human observer. In this work, we explore the utility of computer extracted texture descriptors on multi-parametric MRI (MP-MRI) to provide alternate representations of MRI that may be capable of accentuating subtle micro-architectural di erences between RN and rBT for primary and metastatic (MET) BT patients. We further explore the utility of texture descriptors in identifying the MRI protocol (from amongst T1-w, T2-w and FLAIR) that best distinguishes RN and rBT across two independent cohorts of primary and MET patients. A set of 119 texture descriptors (co-occurrence matrix homogeneity, neighboring gray-level dependence matrix, multi-scale Gaussian derivatives, Law features, and histogram of gradient orientations (HoG)) for modeling di erent macro and micro-scale morphologic changes within the treated lesion area for each MRI protocol were extracted. Principal component analysis based variable importance projection (PCA-VIP), a feature selection method previously developed in our group, was employed to identify the importance of every texture descriptor in distinguishing RN and rBT on MP-MRI. PCA-VIP employs regression analysis to provide an importance score to each feature based on their ability to distinguish the two classes (RN/rBT). The top performing features identi ed via PCA-VIP were employed within a random- forest classi er to di erentiate RN from rBT across two cohorts of 20 primary and 22 MET patients. Our results revealed that, (a) HoG features at di erent orientations were the most important image features for both cohorts, suggesting inherent orientation di erences between RN, and rBT, (b) inverse di erence moment (capturing local intensity homogeneity), and Laws features (capturing local edges and gradients) were identi ed as important for both cohorts, and (c) Gd-C T1-w MRI was identi ed, across the two cohorts, as the best MRI protocol in distinguishing RN/rBT.

  5. Distinguishing benign confounding treatment changes from residual prostate cancer on MRI following laser ablation

    NASA Astrophysics Data System (ADS)

    Litjens, G.; Huisman, H.; Elliott, R.; Shih, N.; Feldman, M.; Viswanath, S.; Fütterer, J.; Bomers, J.; Madabhushi, A.

    2014-03-01

    Laser interstitial thermotherapy (LITT) is a relatively new focal therapy technique for the ablation of localized prostate cancer. However, very little is known about the specific effects of LITT within the ablation zone and the surrounding normal tissue regions. For instance, it is important to be able to assess the extent of residual cancer within the prostate following LITT, which may be masked by thermally induced benign necrotic changes. Fortunately LITT is MRI compatible and hence this allows for quantitatively assessing LITT induced changes via multi-parametric MRI. Of course definite validation of any LITT induced changes on MRI requires confirmation via histopathology. The aim of this study was to quantitatively assess and distinguish the imaging characteristics of prostate cancer and benign confounding treatment changes following LITTon 3 Tesla multi-parametric MRI by carefully mapping the treatment related changes from the ex vivo surgically resected histopathologic specimens onto the pre-operative in vivo imaging. A better understanding of the imaging characteristics of residual disease and successfully ablated tissue might lead to improved treatment monitoring and as such patient prognosis. A unique clinical trial at the Radboud University Medical Center, in which 3 patients underwent a prostatectomy after LITT treatment, yielded ex-vivo histopathologic specimens along with pre- and post-LITT MRI. Using this data we (1) identified the computer extracted MRI signatures associated with treatment effects including benign necrotic changes and residual disease and (2) subsequently evaluated the computer extracted MRI features previously identified in distinguishing LITT induced changes in the ablated area relative to the residual disease. Towards this end first a pathologist annotated the ablated area and the residual disease on the ex-vivo histology and then we transferred the annotations to the post-LITT MRI using semi-automatic elastic registration. The pre- and post-LITT MRI were subsequently registered and computer-derived multi-parametric MRI features extracted to determine differences in feature values between residual disease and successfully ablated tissue to assess treatment response. A scoring metric allowed us to identify those specific computer-extracted MRI features that maximally and differentially expressed between the ablated regions and the residual cancer, on a voxel- by­ voxel basis. Finally, we used a Fuzzy C-Means algorithm to assess the discriminatory power of these selected features. Our results show that specific computer-extracted features from multi-parametric MRI differentially express within the ablated and residual cancer regions, as evidenced by our ability to, on a voxel-by-voxel basis, classify tissue as residual disease. Additionally, we show that change of feature values between pre- and post­-LITT MRI may be useful as a quantitative marker for treatment response (T2-weighted texture and DCE MRI features showed largest differences between residual disease and successfully ablated tissue). Finally, a clustering approach to separate treatment effects and residual disease incorporating both (1) and (2) yielded a maximum area under the ROC curve of 0.97 on a voxel basis across 3 studies.

  6. MRI contrast enhancement using Magnetic Carbon Nanoparticles

    NASA Astrophysics Data System (ADS)

    Chaudhary, Rakesh P.; Kangasniemi, Kim; Takahashi, Masaya; Mohanty, Samarendra K.; Koymen, Ali R.; Department of Physics, University of Texas at Arlington Team; University of Texas Southwestern Medical Center Team

    2014-03-01

    In recent years, nanotechnology has become one of the most exciting forefront fields in cancer diagnosis and therapeutics such as drug delivery, thermal therapy and detection of cancer. Here, we report development of core (Fe)-shell (carbon) nanoparticles with enhanced magnetic properties for contrast enhancement in MRI imaging. These new classes of magnetic carbon nanoparticles (MCNPs) are synthesized using a bottom-up approach in various organic solvents, using the electric plasma discharge generated in the cavitation field of an ultrasonic horn. Gradient echo MRI images of well-dispersed MCNP-solutions (in tube) were acquired. For T2 measurements, a multi echo spin echo sequence was performed. From the slope of the 1/T2 versus concentration plot, the R2 value for different CMCNP-samples was measured. Since MCNPs were found to be extremely non-reactive, and highly absorbing in NIR regime, development of carbon-based MRI contrast enhancement will allow its simultaneous use in biomedical applications. We aim to localize the MCNPs in targeted tissue regions by external DC magnetic field, followed by MRI imaging and subsequent photothermal therapy.

  7. 78 FR 12329 - Distinguishing Medical Device Recalls From Product Enhancements; Reporting Requirements; Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ... mechanism for firms that produce and market medical devices to take timely action to correct violative... SERVICES Food and Drug Administration Distinguishing Medical Device Recalls From Product Enhancements...) is announcing the availability of the draft guidance entitled ``Distinguishing Medical Device...

  8. A robust classifier to distinguish noise from fMRI independent components.

    PubMed

    Sochat, Vanessa; Supekar, Kaustubh; Bustillo, Juan; Calhoun, Vince; Turner, Jessica A; Rubin, Daniel L

    2014-01-01

    Analyzing Functional Magnetic Resonance Imaging (fMRI) of resting brains to determine the spatial location and activity of intrinsic brain networks--a novel and burgeoning research field--is limited by the lack of ground truth and the tendency of analyses to overfit the data. Independent Component Analysis (ICA) is commonly used to separate the data into signal and Gaussian noise components, and then map these components on to spatial networks. Identifying noise from this data, however, is a tedious process that has proven hard to automate, particularly when data from different institutions, subjects, and scanners is used. Here we present an automated method to delineate noisy independent components in ICA using a data-driven infrastructure that queries a database of 246 spatial and temporal features to discover a computational signature of different types of noise. We evaluated the performance of our method to detect noisy components from healthy control fMRI (sensitivity?=?0.91, specificity?=?0.82, cross validation accuracy (CVA)?=?0.87, area under the curve (AUC)?=?0.93), and demonstrate its generalizability by showing equivalent performance on (1) an age- and scanner-matched cohort of schizophrenia patients from the same institution (sensitivity?=?0.89, specificity?=?0.83, CVA?=?0.86), (2) an age-matched cohort on an equivalent scanner from a different institution (sensitivity?=?0.88, specificity?=?0.88, CVA?=?0.88), and (3) an age-matched cohort on a different scanner from a different institution (sensitivity?=?0.72, specificity?=?0.92, CVA?=?0.79). We additionally compare our approach with a recently published method. Our results suggest that our method is robust to noise variations due to population as well as scanner differences, thereby making it well suited to the goal of automatically distinguishing noise from functional networks to enable investigation of human brain function. PMID:24748378

  9. Major mouse placental compartments revealed by diffusion-weighted MRI, contrast-enhanced MRI, and

    E-print Network

    Frydman, Lucio

    Major mouse placental compartments revealed by diffusion-weighted MRI, contrast-enhanced MRI, 2014 (received for review January 27, 2014) Mammalian models, and mouse studies in particular, play, the unavoidable motions, and the challenging air/water/fat heteroge- neities, associated with mouse placental

  10. Dynamic Contrast-Enhanced MRI--Meeting Report

    Cancer.gov

    A. Rationale for the Workshop In the last several years contrast-enhanced MR angiography (CE-MRA) has become a commonly used, commercially available method. In parallel with this, dynamic contrast-enhanced MR imaging (DCE-MRI) has emerged as a promising method for diagnosis and prognosis of cancer. However, widespread use of DCE-MRI is limited by the need for further technical improvements.

  11. Differentiation of Reactive and Tumor Metastatic Lymph Nodes with Diffusion-weighted and SPIO Enhanced MRI

    PubMed Central

    Zhang, Fan; Zhu, Lei; Huang, Xinglu; Niu, Gang; Chen, Siouan

    2012-01-01

    Objectives Determination of lymphatic metastasis is of great importance for both treatment planning and patient prognosis. We aim to distinguish tumor metastatic lymph nodes (TLNs) and reactive lymph nodes (RLNs) with diffusion-weighted and superparamagnetic iron oxide (SPIO) enhanced magnetic resonance imaging (MRI). Materials and methods Ipsilateral popliteal lymph node metastasis or lymphadenitis model was established by hock injection of either luciferase-expressing 4T1 murine breast cancer cells or Complete Freund Adjuvant (CFA) in male Balb/C mice. At different time points after inoculation, bioluminescence imaging, T2-weighted, diffusion-weighted and SPIO enhanced MRI were performed. Imaging findings were confirmed by histopathological staining. Results Size enlargement was observed in both TLNs and RLNs. At day 28, TLNs showed strong bioluminescence signal and bigger size than RLNs (p < 0.01). At early stages up to day 21, both TLNs and RLNs appeared homogeneous on diffusion-weighted imaging (DWI). At day 28, TLNs showed heterogeneous apparent diffusion coefficient (ADC) map with significantly higher average ADC value of 0.41 ± 0.03 × 10?3 mm2/s than that of RLNs (0.34 ± 0.02 10?3 mm2/s, p < 0.05). On SPIO enhanced MRI, both TLNs and RLNs showed distinct T2 signal reduction at day 21 after inoculation. At day 28, TLNs demonstrated partial uptake of the iron oxide particles, which was confirmed by Prussian blue staining. Conclusions Both diffusion-weighted and SPIO enhanced MRI can distinguish tumor metastatic lymph nodes from reactive lymph nodes. However, neither method is able to detect tumor metastasis to the draining lymph nodes at early stages. PMID:22588595

  12. Manganese-Enhanced MRI: Biological Applications in Neuroscience

    PubMed Central

    Malheiros, Jackeline Moraes; Paiva, Fernando Fernandes; Longo, Beatriz Monteiro; Hamani, Clement; Covolan, Luciene

    2015-01-01

    Magnetic resonance imaging (MRI) is an excellent non-invasive tool to investigate biological systems. The administration of the paramagnetic divalent ion manganese (Mn2+) enhances MRI contrast in vivo. Due to similarities between Mn2+ and calcium (Ca2+), the premise of manganese-enhanced MRI (MEMRI) is that the former may enter neurons and other excitable cells through voltage-gated Ca2+ channels. As such, MEMRI has been used to trace neuronal pathways, define morphological boundaries, and study connectivity in morphological and functional imaging studies. In this article, we provide a brief overview of MEMRI and discuss recently published data to illustrate the usefulness of this method, particularly in animal models. PMID:26217304

  13. Engineering Gd-loaded nanoparticles to enhance MRI sensitivity via T1 shortening

    NASA Astrophysics Data System (ADS)

    Bruckman, Michael A.; Yu, Xin; Steinmetz, Nicole F.

    2013-11-01

    Magnetic resonance imaging (MRI) is a noninvasive imaging technique capable of obtaining high-resolution anatomical images of the body. Major drawbacks of MRI are the low contrast agent sensitivity and inability to distinguish healthy tissue from diseased tissue, making early detection challenging. To address this technological hurdle, paramagnetic contrast agents have been developed to increase the longitudinal relaxivity, leading to an increased signal-to-noise ratio. This review focuses on methods and principles that enabled the design and engineering of nanoparticles to deliver contrast agents with enhanced ionic relaxivities. Different engineering strategies and nanoparticle platforms will be compared in terms of their manufacturability, biocompatibility properties, and their overall potential to make an impact in clinical MR imaging.

  14. Characterization of focal hepatic lesions with SPIO-enhanced MRI

    PubMed Central

    Zheng, Wei-Wei; Zhou, Kang-Rong; Chen, Zu-Wang; Shen, Ji-Zhang; Chen, Cai-Zhong; Zhang, Shu-Jie

    2002-01-01

    AIM: To evaluate the value of superparamagnetic iron oxide (SPIO) enhanced MRI in characterizing focal hepatic lesions. METHODS: Forty-three patients (32 men, 11 women, mean age 51 years, age range 25-74 years) with previously identified focal hepatic lesions were enrolled into this study. All the patients underwent plain,Gd-DTPA enhanced MRI and the SPIO enhanced MRI 1-7 d later. The surgico-pathologic diagnosis was aestablished in 31 cases and the diagnosis in other 12 cases was made on the basis of clinical findings and biochemical tests. The signal changes of lesions were analyzed and the CNRs of lesion-to-liver were measured before and after SPIO enhancement. The data were analyzed by paired t test. RESULTS: Focal hepatic lesions included primary hepatocellular carcinoma (HCC, n = 22), hemangioma (n = 5), cyst (n = 4), metastases (n = 5), cirrhotic nodule (n = 4), focal nodular hyperplasia (FNH, n = 5) and other miscellaneous lesions (n = 6). After SPIO enhancement HCC demonstrated iso- or slight hyperintensity on T1WI and moderate hyperintersity on T2WI, hemangioma showed moderate hyperintensity on T1WI and obvious hyperintensity on T2WI, the SI of cyst had no change either on T1WI or on T2WI, cirrhotic nodules revealed iso-intensity on T2WI, and the SI of FNH decreased significantlyon T2WI. No specific manifestations were found in the other 6 miscellaneous lesions after SPIO enhancement. CONCLUSION: SPIO enhanced-MRI can improve the characterization confidence for diagnosis of focal hepatic lesions. PMID:11833077

  15. Classic models for dynamic contrast-enhanced MRI.

    PubMed

    Sourbron, Steven P; Buckley, David L

    2013-08-01

    Dynamic contrast-enhanced MRI (DCE-MRI) is a functional MRI method where T1 -weighted MR images are acquired dynamically after bolus injection of a contrast agent. The data can be interpreted in terms of physiological tissue characteristics by applying the principles of tracer-kinetic modelling. In the brain, DCE-MRI enables measurement of cerebral blood flow (CBF), cerebral blood volume (CBV), blood-brain barrier (BBB) permeability-surface area product (PS) and the volume of the interstitium (ve ). These parameters can be combined to form others such as the volume-transfer constant K(trans) , the extraction fraction E and the contrast-agent mean transit times through the intra- and extravascular spaces. A first generation of tracer-kinetic models for DCE-MRI was developed in the early 1990s and has become a standard in many applications. Subsequent improvements in DCE-MRI data quality have driven the development of a second generation of more complex models. They are increasingly used, but it is not always clear how they relate to the models of the first generation or to the model-free deconvolution methods for tissues with intact BBB. This lack of understanding is leading to increasing confusion on when to use which model and how to interpret the parameters. The purpose of this review is to clarify the relation between models of the first and second generations and between model-based and model-free methods. All quantities are defined using a generic terminology to ensure the widest possible scope and to reveal the link between applications in the brain and in other organs. PMID:23674304

  16. Consensus Recommendation for Acquisition of Dynamic Contrasted-Enhanced MRI Data in Oncology

    Cancer.gov

    Establish minimum requirements for standardized data acquisition for oncologic applications of dynamic contrast enhanced MRI (DCE-MRI) to allow integration of data from different institutions and comparison of various approaches for data analysis.

  17. Dynamic Contrast-Enhanced MRI Evaluation of Cerebral Cavernous Malformations

    PubMed Central

    Hart, B. L.; Taheri, S.; Rosenberg, G. A.; Morrison, L. A.

    2013-01-01

    The aim of this study is to quantitatively evaluate the behavior of CNS cavernous malformations (CCMs) using a dynamic contrast-enhanced MRI (DCEMRI) technique sensitive for slow transfer rates of gadolinium. The prospective study was approved by the institutional review board and was HIPPA compliant. Written informed consent was obtained from 14 subjects with familial CCMs (4 men and 10 women, ages 22–76 years, mean 48.1 years). Following routine anatomic MRI of the brain, DCEMRI was performed for six slices, using T1 mapping with partial inversion recovery (TAPIR) to calculate T1 values, following administration of 0.025 mmol/kg gadolinium DTPA. The transfer rate (Ki) was calculated using the Patlak model, and Ki within CCMs was compared to normal-appearing white matter as well as to 17 normal control subjects previously studied. All subjects had typical MRI appearance of CCMs. Thirty-nine CCMs were studied using DCEMRI. Ki was low or normal in 12 lesions and elevated from 1.4 to 12 times higher than background in the remaining 27 lesions. Ki ranged from 2.1E–6 to 9.63E–4 min?1, mean 3.55E–4. Normal-appearing white matter in the CCM patients had a mean Ki of 1.57E–4, not statistically different from mean WM Ki of 1.47E–4 in controls. TAPIR-based DCEMRI technique permits quantifiable assessment of CCMs in vivo and reveals considerable differences not seen with conventional MRI. Potential applications include correlation with biologic behavior such as lesion growth or hemorrage, and measurement of drug effects. PMID:24323376

  18. Dynamic contrast-enhanced MRI evaluation of cerebral cavernous malformations.

    PubMed

    Hart, Blaine L; Taheri, Saeid; Rosenberg, Gary A; Morrison, Leslie A

    2013-10-01

    The aim of this study is to quantitatively evaluate the behavior of CNS cavernous malformations (CCMs) using a dynamic contrast-enhanced MRI (DCEMRI) technique sensitive for slow transfer rates of gadolinium. The prospective study was approved by the institutional review board and was HIPPA compliant. Written informed consent was obtained from 14 subjects with familial CCMs (4 men and 10 women, ages 22-76 years, mean 48.1 years). Following routine anatomic MRI of the brain, DCEMRI was performed for six slices, using T1 mapping with partial inversion recovery (TAPIR) to calculate T1 values, following administration of 0.025 mmol/kg gadolinium DTPA. The transfer rate (Ki) was calculated using the Patlak model, and Ki within CCMs was compared to normal-appearing white matter as well as to 17 normal control subjects previously studied. All subjects had typical MRI appearance of CCMs. Thirty-nine CCMs were studied using DCEMRI. Ki was low or normal in 12 lesions and elevated from 1.4 to 12 times higher than background in the remaining 27 lesions. Ki ranged from 2.1E-6 to 9.63E-4 min(-1), mean 3.55E-4. Normal-appearing white matter in the CCM patients had a mean Ki of 1.57E-4, not statistically different from mean WM Ki of 1.47E-4 in controls. TAPIR-based DCEMRI technique permits quantifiable assessment of CCMs in vivo and reveals considerable differences not seen with conventional MRI. Potential applications include correlation with biologic behavior such as lesion growth or hemorrage, and measurement of drug effects. PMID:24323376

  19. The intravertebral cleft in benign vertebral compression fracture: the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI.

    PubMed

    Ryu, C-W; Han, H; Lee, Y-M; Lim, M-K

    2009-12-01

    We compared the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI (CEMRI) in diagnosing intravertebral clefts in benign vertebral compression fractures (VCFs). We retrospectively reviewed 99 consecutive patients who had undergone percutaneous vertebroplasty for VCFs. A cleft was defined as a signal void or hyperintense area on non-enhanced MRI (T(1) and T(2) weighted imaging) or as a hypointense area within a diffusely enhanced vertebra on CEMRI. A cleft was confirmed as a solid opacification on post-procedural radiographs. The interobserver reliability and MRI diagnostic performance were evaluated. The interobserver reliability of non-enhanced MRI was substantial (k _ 0.698) and the interobserver reliability of CEMRI was almost perfect (k _ 0.836). Post-procedural radiographs showed solid cleft opacification in 32 out of the 99 cases. The sensitivity and specificity of non-enhanced MRI were 0.72 and 0.82 (observer 1) and 0.63 and 0.87 (observer 2), respectively. The sensitivity and specificity of CEMRI were 0.94 and 0.63 (observer 1) and 0.85 and 0.60 (observer 2), respectively. The sensitivity of CEMRI was significantly higher than that of non-enhanced MRI, and the specificity of non-enhanced MRI was higher than that of CEMRI. CEMRI was highly reliable and sensitive, and non-enhanced MRI was specific for intravertebral clefts. Therefore, spine MRIs, including CEMRI, could provide useful information about intravertebral clefts before percutaneous vertebroplasty. PMID:19581311

  20. Differentiation of solid pancreatic tumors by using dynamic contrast-enhanced MRI

    NASA Astrophysics Data System (ADS)

    Choi, Seung Joon; Kim, Hyung Sik; Park, Hyunjin

    2014-01-01

    Distinguishing among different solid pancreatic tumor types, pancreatic ductal adenocarcinomas, neuroendocrine tumors (NETs), and solid pseudopapillary tumors (SPTs) is important, as the treatment options are vastly different. This study compared characteristics of solid pancreatic tumors by using dynamic contrast enhanced magnetic resonance imaging (MRI). Fifty patients underwent MR imaging of pancreatic masses with a histopathology that was later confirmed as an adenocarcinoma (n = 27), a NET (n = 16), and a SPT (n = 7). For qualitative analysis, two reviewers evaluated the morphologic features of the tumors: locations, margins, shapes, contained products, pancreatic ductal dilatation, and grade of signal intensity (SI). For the quantitative analysis, all phases of the MR images were co-registered using proprietary image registration software; thus, a region of interest (ROI) defined on one phase could be re-applied in other phases. The following four ratios were considered: tumor-to-uninvolved pancreas SI ratio, percent SI change, tumor-touninvolved pancreas enhancement index, and arterial-to-delayed washout rate. The areas under the receiver operating characteristic (ROC) curves were assessed for the four ratios. Adenocarcinomas had ill-defined margins, irregular shapes, and ductal dilatation compared with NETs and SPTs (P < 0.001). The tumor-to-uninvolved pancreas ratio on all dynamic phases was significantly higher for NETs than for both adenocarcinomas and SPTs (P < 0.05). Percentage SI changes of pancreatic tumors on the pancreatic and the portal venous phases were significantly higher for NETs than for both adenocarcinomas and SPTs (P < 0.05). A significant difference between NETs and adenocarcinomas was also found with respect to the tumor-to-uninvolved pancreas enhancement index and arterial-to-delayed washout rate. The percentage SI changes in the pancreatic phase and the arterial-to-delayed washout rate best distinguished between adenocarcinomas and NETs with the area under the ROC curve being 0.87. The percentage SI changes in the pancreatic and the portal venous phases best distinguished between NETs and SPTs with area under the ROC curve 0.87. In summary, contrast-enhanced MRI can be useful in differentiating solid pancreatic tumors in qualitative and quantitative analyses.

  1. Use of iron colloid-enhanced MRI for study of acute radiation-induced hepatic injury

    SciTech Connect

    Suto, Yuji; Ametani, Masaki; Kato, Takashi; Hashimoto, Masayuki; Kamba, Masayuki; Sugihara, Syuji; Ohta, Yoshio

    1996-03-01

    We present a case with acute radiation-induced hepatic injury using chondroitin sulfate iron colloid (CSIC)-enhanced MRI. Uptake of CSIC was decreased in the irradiated portion of the liver. CSIC-enhanced MRI is useful for obtaining information on the function of the reticuloendothelial system and demarcates between irradiated and nonirradiated zones. 18 refs., 3 figs

  2. Synthesis and characterization of magnetoliposomes for MRI contrast enhancement.

    PubMed

    Faria, M R; Cruz, M M; Gonçalves, M C; Carvalho, A; Feio, G; Martins, M B F

    2013-03-25

    This work assesses the characteristics of magnetoliposomes of soybean phosphatidylcholine (SPC):cholesterol (Chol) loaded with superparamagnetic iron oxide nanoparticles (IONPs) stabilized with tetramethylammonium hydroxide (TMAOH) and their capacity to enhance magnetic resonance imaging (MRI) contrast. Magnetoliposomes of SPC were used for comparative studies. IONPs and magnetoliposomes were characterized using transmission electron microscopy, dynamic light scattering, SQUID magnetometry, FTIR and MRI. The saturation magnetization at 10K was ~0.06 Am(2)/kg for SPC:Chol magnetoliposomes with 7 g iron oxide/mol of lipid and ~0.05 Am(2)/kg for SPC magnetoliposomes with 21 g iron oxide/mol of lipid. As these values are associated with the number of incorporated magnetic IONPs, the saturation magnetization is 1.2 times higher for magnetoliposomes of SPC:Chol as compared with magnetoliposomes of SPC alone. The behavior of temperature dependence in both cases is typical of superparamagnetic particles. FTIR spectra evidence the increase of magnetoliposome membrane ordering with the presence of Chol. Principal component analysis (PCA) applied to FTIR spectra evidenced a clear distinction between scores for SPC:Chol, and SPC magnetoliposomes and for SPC empty liposomes. PCA applied to FTIR data differentiate magnetoliposomes from empty liposomes. MR images of aqueous phantoms obtained with and without magnetoliposomes, clearly evidence their effect on T2 image weighting. PMID:23422275

  3. Identifying Triple-Negative Breast Cancer Using Background Parenchymal Enhancement Heterogeneity on Dynamic Contrast-Enhanced MRI: A Pilot Radiomics Study

    PubMed Central

    Wang, Jeff; Kato, Fumi; Oyama-Manabe, Noriko; Li, Ruijiang; Cui, Yi; Tha, Khin Khin; Yamashita, Hiroko; Kudo, Kohsuke; Shirato, Hiroki

    2015-01-01

    Objectives To determine the added discriminative value of detailed quantitative characterization of background parenchymal enhancement in addition to the tumor itself on dynamic contrast-enhanced (DCE) MRI at 3.0 Tesla in identifying “triple-negative" breast cancers. Materials and Methods In this Institutional Review Board-approved retrospective study, DCE-MRI of 84 women presenting 88 invasive carcinomas were evaluated by a radiologist and analyzed using quantitative computer-aided techniques. Each tumor and its surrounding parenchyma were segmented semi-automatically in 3-D. A total of 85 imaging features were extracted from the two regions, including morphologic, densitometric, and statistical texture measures of enhancement. A small subset of optimal features was selected using an efficient sequential forward floating search algorithm. To distinguish triple-negative cancers from other subtypes, we built predictive models based on support vector machines. Their classification performance was assessed with the area under receiver operating characteristic curve (AUC) using cross-validation. Results Imaging features based on the tumor region achieved an AUC of 0.782 in differentiating triple-negative cancers from others, in line with the current state of the art. When background parenchymal enhancement features were included, the AUC increased significantly to 0.878 (p<0.01). Similar improvements were seen in nearly all subtype classification tasks undertaken. Notably, amongst the most discriminating features for predicting triple-negative cancers were textures of background parenchymal enhancement. Conclusions Considering the tumor as well as its surrounding parenchyma on DCE-MRI for radiomic image phenotyping provides useful information for identifying triple-negative breast cancers. Heterogeneity of background parenchymal enhancement, characterized by quantitative texture features on DCE-MRI, adds value to such differentiation models as they are strongly associated with the triple-negative subtype. Prospective validation studies are warranted to confirm these findings and determine potential implications. PMID:26600392

  4. ERK'2007, Portoroz, B:191-194 191 Motion correction of contrast-enhanced MRI time series of kidney

    E-print Network

    Kovacic, Stanislav

    ERK'2007, Portoroz, B:191-194 191 Motion correction of contrast-enhanced MRI time series of kidney In this paper we focus on motion correction of contrast enhanced kidney MRI time series, which is an important: motion correction, image registration, contrast-enhanced MRI. 1 Introduction The kidneys maintain normal

  5. 2011 Spring : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Brooker John William Distinguished Brooks Jillian Caroline Distinguished Brooks Tyler Lynn Distinguished Buchanan Blake Conrad Distinguished Buckley Megan R Distinguished Budde Craig A Distinguished

  6. 2009 Spring : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Applewhite Madelyn Ellen Distinguished Aragone Rachel Distinguished Ard Sheri M Distinguished Louise Distinguished Campbell Christopher Warren Distinguished Campbell Samantha Lyn Distinguished Carson Nicole N Distinguished Cartee Tiffany Faith Distinguished Casamassa David James Distinguished

  7. 2013 Spring : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Kristinia Michelle Distinguished Acsell Austin Mitchell Distinguished Adams MacKenzie Rachel Distinguished Distinguished Balltrip Margaret Keith Distinguished Bannister Shayna Rachel Distinguished Barber Laura Ann Cary Carr Patricia Ann Distinguished Carroll Carson David Distinguished Carter Elizabeth Anne Distinguished

  8. 2012 Spring : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Beacham Cameron Ray Distinguished Beal Callie Elizabeth Distinguished Becker-Krail Darius Kendall Currin Distinguished Biga Charlotte Kendall Distinguished Blackwell Evan Robert Distinguished Distinguished Bronsky Gabrielle Elizabeth Distinguished Brooksbank Michelle Dales Distinguished Brown Cameron

  9. 2009 Fall : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Merve Distinguished Albia Nathaniel J Distinguished Allen Daniel Patterson Distinguished Allen Emily M Antonnette Distinguished Barnett Naomi Stewart Distinguished Barrick Joshua David Distinguished Bartley Bell Lorin Legene Distinguished Bellamy Kara Nicole Distinguished Benjamin Abigail Distinguished

  10. 2008 Fall : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Alexander John Parks Distinguished Alge Mikah Anne Distinguished Allen Elizabeth Easterling Baust Amanda L Distinguished Beard John Elliot Distinguished Beckwith Brantley Wallace Distinguished Laura E Distinguished Brown Kyle R Distinguished Brown Leland D Distinguished Brown Lindsay Jane

  11. 2014 Fall : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Bagley Clara Mae Distinguished Bailey Ana Camila Distinguished Bailey Caitlyn Elizabeth Distinguished Elizabeth Distinguished Barton Hayley Morgan Distinguished Barton Maitland Elizabeth Distinguished Bass

  12. 2014 Spring : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Batson Peyton Lee Distinguished Bauer Chelsea Morgan Distinguished 1 #12;2014 Spring : Distinguished Budz Dina Bre-Ane Distinguished Buford Chelsea Colleen Distinguished Bui Jenny Distinguished Burger

  13. 2012 Fall : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Bauer Chelsea Morgan Distinguished Baxley Jami Reid Distinguished Baxley Taylor Dianne Distinguished Becker Russell Hamilton Monte Distinguished Beckett Ethan Patrick Distinguished Beckman Joshua

  14. 2011 Fall : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Bonnette Chanel Monea Distinguished Borges Catherine Rebecca Distinguished Bowen Meredith Ann Austin Russell Distinguished Brown Breighone Jacel Distinguished Brown Daniel Adam Distinguished Brown

  15. 2010 Spring : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Caitlin Alice Distinguished Barton Cory A Distinguished Bath Sean C Distinguished Beasley Elizabeth Lines Distinguished Becker Russell Hamilton Monte Distinguished Beckett Ethan Patrick Distinguished Beckett Kuleigh

  16. Emerging role of contrast-enhanced MRI in diagnosing vascular malformations.

    PubMed

    Turley, Ryan S; Lidsky, Michael E; Markovic, Jovan N; Shortell, Cynthia K

    2014-07-01

    Vascular malformations comprise a diverse and rare group of lesions which generally pose a formidable treatment challenge. Requisite for optimal surgical planning are imaging modalities capable of delineating involved anatomy and malformation flow characteristics. In this regard, we and others have purported the advantages of contrast-enhanced MRI. Here, we review the current body of literature regarding the emerging of role of contrast enhanced MRI for the management of vascular malformations. PMID:25301311

  17. Ultrafast 3D spin-echo acquisition improves Gadolinium-enhanced MRI signal contrast enhancement

    PubMed Central

    Han, S. H.; Cho, F. H.; Song, Y. K.; Paulsen, J.; Song, Y. Q.; Kim, Y. R.; Kim, J. K.; Cho, G.; Cho, H.

    2014-01-01

    Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T2* effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (×32) and compressed sensing (CS) sampling (×8) allowed highly-accelerated 3D Multiple-Modulation-Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (×7) over that of corresponding FLASH acquisitions (×2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution. PMID:24863102

  18. Diffuse dural gadolinium MRI enhancement associated with bilateral chronic subdural hematomas.

    PubMed

    Blitshteyn, Svetlana; Mechtler, Laszlo L; Bakshi, Rohit

    2004-01-01

    Chronic subdural hematomas (CSDHs) typically present with cognitive dysfunction and a history of trauma. Localized dural enhancement on postcontrast MRI scans associated with the surrounding membrane has been described in CSDH. We present an 83-year-old man with rapidly progressing cognitive dysfunction 4 weeks after head trauma related to a fall. MRI showed CSDHs, which in addition to localized dural gadolinium enhancement, showed a marked diffuse, symmetric, contiguous pachymeningeal enhancement of the supratentorial and infratentorial intracranial dural mater. Meningeal biopsy failed to disclose an infectious or neoplastic cause of the enhancement and instead showed fibrocollagenous change. We conclude that diffuse dural enhancement on MRI scans associated with CSDH cause does not necessarily indicate a superimposed process such as infection or malignancy. CSDH should be considered in the differential diagnosis of diffuse dural enhancement, especially when supported by appropriate clinical findings. PMID:15050219

  19. Use of an internal reference in semi-quantitative dynamic contrast-enhanced MRI (DCE MRI) of indeterminate adnexal masses

    PubMed Central

    Benardin, L; Booth, T C; Miquel, M E; Dilks, P; Sahdev, A; Rockall, A G

    2014-01-01

    Objective: Semi-quantitative dynamic contrast-enhanced MRI (DCE MRI) has proven useful in discriminating benign from borderline/malignant adnexal lesions. Our aim was to assess if the use of a lesion-to-internal-reference ratio improved the performance in characterizing adnexal masses and which internal reference was suitable. Methods: Semi-quantitative DCE MRI images of 71 indeterminate adnexal lesions were retrospectively reviewed. A region of interest was manually drawn onto the enhancing solid component, psoas muscle and normal outer myometrium. The DCE parameters were evaluated, and the lesion-to-internal-reference ratios were calculated. Results: When the wash in rate of the lesion was higher than that of the myometrium, 97% specificity and 12% sensitivity for borderline/malignancy was reached. When the maximum relative enhancement and maximum absolute enhancement (SImax) of the lesion was less than those of the psoas, 100% specificity for benignity was achieved. The highest area under the curve (AUC) (0.807) was achieved using a SImax lesion–myometrium ratio. A slightly lower AUC (0.799) was achieved using a SImax lesion–psoas ratio, but the psoas muscle was more frequently measurable in the same slice as the lesion ROI. Although the AUC was higher, when using ratios instead of individual DCE values, this was not significantly different. Conclusion: DCE MRI has added diagnostic value in the assessment of adnexal lesions, and the use of internal references enables high specificity for malignancy and benignity. Lesion–internal-reference ratios have no added diagnostic value over DCE values alone. Advances in knowledge: Both psoas muscle and myometrium are suitable internal references in the DCE assessment of adnexal lesions enabling high specificity for malignancy and benignity. PMID:25237836

  20. Distinguishing adjacent molecules on a surface using plasmon-enhanced Raman scattering.

    PubMed

    Jiang, Song; Zhang, Yao; Zhang, Rui; Hu, Chunrui; Liao, Menghan; Luo, Yi; Yang, Jinlong; Dong, Zhenchao; Hou, J G

    2015-10-01

    Unambiguous chemical identification of individual molecules closely packed on a surface can offer the possibility to address single chemical species and monitor their behaviour at the individual level. Such a degree of spatial resolution can in principle be achieved by detecting their vibrational fingerprints using tip-enhanced Raman scattering (TERS). The chemical specificity of TERS can be combined with the high spatial resolution of scanning probe microscopy techniques, an approach that has stimulated extensive research in the field. Recently, the development of nonlinear TERS in a scanning tunnelling microscope has pushed the spatial resolution down to ?0.5?nm, allowing the identification of the vibrational fingerprints of isolated molecules on Raman-silent metal surfaces. Although the nonlinear TERS component is likely to help sharpen the optical contrast of the acquired image, the TERS signal still contains a considerable contribution from the linear term, which is spatially less confined. Therefore, in the presence of different adjacent molecules, a mixing of Raman signals may result. Here, we show that using a nonlinear scanning tunnelling microscope-controlled TERS set-up, two different adjacent molecules that are within van der Waals contact and of very similar chemical structure (a metal-centred porphyrin and a free-base porphyrin) on a silver surface can be distinguished in real space. In addition, with the help of density functional theory simulations, we are also able to determine their adsorption configurations and orientations on step edges and terraces. PMID:26214250

  1. Distinguishing adjacent molecules on a surface using plasmon-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Jiang, Song; Zhang, Yao; Zhang, Rui; Hu, Chunrui; Liao, Menghan; Luo, Yi; Yang, Jinlong; Dong, Zhenchao; Hou, J. G.

    2015-10-01

    Unambiguous chemical identification of individual molecules closely packed on a surface can offer the possibility to address single chemical species and monitor their behaviour at the individual level. Such a degree of spatial resolution can in principle be achieved by detecting their vibrational fingerprints using tip-enhanced Raman scattering (TERS). The chemical specificity of TERS can be combined with the high spatial resolution of scanning probe microscopy techniques, an approach that has stimulated extensive research in the field. Recently, the development of nonlinear TERS in a scanning tunnelling microscope has pushed the spatial resolution down to ?0.5?nm, allowing the identification of the vibrational fingerprints of isolated molecules on Raman-silent metal surfaces. Although the nonlinear TERS component is likely to help sharpen the optical contrast of the acquired image, the TERS signal still contains a considerable contribution from the linear term, which is spatially less confined. Therefore, in the presence of different adjacent molecules, a mixing of Raman signals may result. Here, we show that using a nonlinear scanning tunnelling microscope-controlled TERS set-up, two different adjacent molecules that are within van der Waals contact and of very similar chemical structure (a metal-centred porphyrin and a free-base porphyrin) on a silver surface can be distinguished in real space. In addition, with the help of density functional theory simulations, we are also able to determine their adsorption configurations and orientations on step edges and terraces.

  2. 2010 Fall : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Margaret Distinguished Becker Russell Hamilton Monte Distinguished 1 #12;2010 Fall : Distinguished Honors Borgeson Chelsea Virginia Distinguished Bostick William Brooks Distinguished Bostrom Seth Michael

  3. Major mouse placental compartments revealed by diffusion-weighted MRI, contrast-enhanced MRI, and fluorescence imaging

    PubMed Central

    Solomon, Eddy; Avni, Reut; Hadas, Ron; Raz, Tal; Garbow, Joel Richard; Bendel, Peter; Frydman, Lucio; Neeman, Michal

    2014-01-01

    Mammalian models, and mouse studies in particular, play a central role in our understanding of placental development. Magnetic resonance imaging (MRI) could be a valuable tool to further these studies, providing both structural and functional information. As fluid dynamics throughout the placenta are driven by a variety of flow and diffusion processes, diffusion-weighted MRI could enhance our understanding of the exchange properties of maternal and fetal blood pools—and thereby of placental function. These studies, however, have so far been hindered by the small sizes, the unavoidable motions, and the challenging air/water/fat heterogeneities, associated with mouse placental environments. The present study demonstrates that emerging methods based on the spatiotemporal encoding (SPEN) of the MRI information can robustly overcome these obstacles. Using SPEN MRI in combination with albumin-based contrast agents, we analyzed the diffusion behavior of developing placentas in a cohort of mice. These studies successfully discriminated the maternal from the fetal blood flows; the two orders of magnitude differences measured in these fluids’ apparent diffusion coefficients suggest a nearly free diffusion behavior for the former and a strong flow-based component for the latter. An intermediate behavior was observed by these methods for a third compartment that, based on maternal albumin endocytosis, was associated with trophoblastic cells in the interphase labyrinth. Structural features associated with these dynamic measurements were consistent with independent intravital and ex vivo fluorescence microscopy studies and are discussed within the context of the anatomy of developing mouse placentas. PMID:24969421

  4. Glucose Administration Enhances fMRI Brain Activation and Connectivity Related to Episodic Memory Encoding for Neutral and Emotional Stimuli

    ERIC Educational Resources Information Center

    Parent, Marise B.; Krebs-Kraft, Desiree L.; Ryan, John P.; Wilson, Jennifer S.; Harenski, Carla; Hamann, Stephan

    2011-01-01

    Glucose enhances memory in a variety of species. In humans, glucose administration enhances episodic memory encoding, although little is known regarding the neural mechanisms underlying these effects. Here we examined whether elevating blood glucose would enhance functional MRI (fMRI) activation and connectivity in brain regions associated with…

  5. An Aid to Decision-Making in Therapy of Retroperitoneal Fibrosis: Dynamic Enhancement Analysis of Gadolinium MRI

    PubMed Central

    Brandt, Alexander Sascha; Kamper, Lars; Kukuk, Sonja; Piroth, Werner; Haage, Patrick; Roth, Stephan

    2013-01-01

    Background Idiopathic retroperitoneal fibrosis (IRF) as an uncommon cause of obstructive uropathy is often primarily treated medically by the attending urologist. We evaluated dynamic enhancement analysis (DEA) as a possible predictor of response to medical treatment and for treatment monitoring. Methods From 2007, 24 patients with fibrosis were assessed by magnetic resonance imaging (MRI) with DEA. The dynamic enhancement quotient (DEQ) was measured before therapy with prednisone (n = 12) or tamoxifen (n = 12) and in follow-up investigations after 3 and 6 months. Response to medical treatment was recorded by changes in the retroperitoneal mass on MRI and possible relief of ureteral obstruction, which was monitored by intravenous pyelogram and/or MAG3 scan after removal of DJ stents. Results Treatment groups did not differ significantly as to age, gender, or laboratory values, and response to medical treatment showed no significant difference between agents. Overall there were no cases of progression, 2 cases of stable disease, 11 cases of mild fibrotic regression, and 11 of significant or complete regression. DJ stents could successfully be removed in 21 of 35 renal units (60.0%). In a total of 61 DEAs the DEQ was significantly higher (P < 0.001) in patients with a good response (DEQ = 4.02) than in those with an average response (3.11) or none (2.14). Conclusions DEA was able to distinguish between patients with different response rates to medical treatment of IRF and may be useful to individualize therapeutic decision-making. PMID:23390476

  6. Signal enhancement ratio (SER) quantified from breast DCE-MRI and breast cancer risk

    NASA Astrophysics Data System (ADS)

    Wu, Shandong; Kurland, Brenda F.; Berg, Wendie A.; Zuley, Margarita L.; Jankowitz, Rachel C.; Sumkin, Jules; Gur, David

    2015-03-01

    Breast magnetic resonance imaging (MRI) is recommended as an adjunct to mammography for women who are considered at elevated risk of developing breast cancer. As a key component of breast MRI, dynamic contrast-enhanced MRI (DCE-MRI) uses a contrast agent to provide high intensity contrast between breast tissues, making it sensitive to tissue composition and vascularity. Breast DCE-MRI characterizes certain physiologic properties of breast tissue that are potentially related to breast cancer risk. Studies have shown that increased background parenchymal enhancement (BPE), which is the contrast enhancement occurring in normal cancer-unaffected breast tissues in post-contrast sequences, predicts increased breast cancer risk. Signal enhancement ratio (SER) computed from pre-contrast and post-contrast sequences in DCE-MRI measures change in signal intensity due to contrast uptake over time and is a measure of contrast enhancement kinetics. SER quantified in breast tumor has been shown potential as a biomarker for characterizing tumor response to treatments. In this work we investigated the relationship between quantitative measures of SER and breast cancer risk. A pilot retrospective case-control study was performed using a cohort of 102 women, consisting of 51 women who had diagnosed with unilateral breast cancer and 51 matched controls (by age and MRI date) with a unilateral biopsy-proven benign lesion. SER was quantified using fully-automated computerized algorithms and three SER-derived quantitative volume measures were compared between the cancer cases and controls using logistic regression analysis. Our preliminary results showed that SER is associated with breast cancer risk, after adjustment for the Breast Imaging Reporting and Data System (BI-RADS)-based mammographic breast density measures. This pilot study indicated that SER has potential for use as a risk factor for breast cancer risk assessment in women at elevated risk of developing breast cancer.

  7. 78 FR 12329 - Distinguishing Medical Device Recalls From Product Enhancements; Reporting Requirements; Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ...have a favorable impact on medical device safety and are part...helpful in properly identifying medical device recalls and applying...receive ``Distinguishing Medical Device Recalls From Product...February 15, 2013. Leslie Kux, Assistant Commissioner for...

  8. 2013 Fall : Distinguished Honors Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Bair Keira Marie Distinguished Baker Huntley J Distinguished Baldini Julia Hope Distinguished Barber Zachary Michael Distinguished 1 #12;2013 Fall : Distinguished Honors LAST_NAME FIRST_NAME MIDDLE Distinguished Bishop William McGeehan Distinguished Black Lauren Rise' Distinguished Blumenthal Alicia Ann

  9. An Integrated Method of Adaptive Enhancement for Unsupervised Segmentation of MRI Brain Images

    E-print Network

    Pizurica, Aleksandra

    Spinal Fluid), GM (Gray Matter), WM (White Matter). Firstly, we de-noise the images using a newly proposed- graded by noise perturbations in low contrast and low SNR (Signal-to-Noise Ratio) images, eAn Integrated Method of Adaptive Enhancement for Unsupervised Segmentation of MRI Brain Images

  10. The Potential for an Enhanced Role for MRI in Radiation-therapy Treatment Planning

    PubMed Central

    Metcalfe, P.; Liney, G. P.; Holloway, L.; Walker, A.; Barton, M.; Delaney, G. P.; Vinod, S.; Tomé, W.

    2013-01-01

    The exquisite soft-tissue contrast of magnetic resonance imaging (MRI) has meant that the technique is having an increasing role in contouring the gross tumor volume (GTV) and organs at risk (OAR) in radiation therapy treatment planning systems (TPS). MRI-planning scans from diagnostic MRI scanners are currently incorporated into the planning process by being registered to CT data. The soft-tissue data from the MRI provides target outline guidance and the CT provides a solid geometric and electron density map for accurate dose calculation on the TPS computer. There is increasing interest in MRI machine placement in radiotherapy clinics as an adjunct to CT simulators. Most vendors now offer 70 cm bores with flat couch inserts and specialised RF coil designs. We would refer to these devices as MR-simulators. There is also research into the future application of MR-simulators independent of CT and as in-room image-guidance devices. It is within the background of this increased interest in the utility of MRI in radiotherapy treatment planning that this paper is couched. The paper outlines publications that deal with standard MRI sequences used in current clinical practice. It then discusses the potential for using processed functional diffusion maps (fDM) derived from diffusion weighted image sequences in tracking tumor activity and tumor recurrence. Next, this paper reviews publications that describe the use of MRI in patient-management applications that may, in turn, be relevant to radiotherapy treatment planning. The review briefly discusses the concepts behind functional techniques such as dynamic contrast enhanced (DCE), diffusion-weighted (DW) MRI sequences and magnetic resonance spectroscopic imaging (MRSI). Significant applications of MR are discussed in terms of the following treatment sites: brain, head and neck, breast, lung, prostate and cervix. While not yet routine, the use of apparent diffusion coefficient (ADC) map analysis indicates an exciting future application for functional MRI. Although DW-MRI has not yet been routinely used in boost adaptive techniques, it is being assessed in cohort studies for sub-volume boosting in prostate tumors. PMID:23617289

  11. Synergistic enhancement of iron oxide nanoparticle and gadolinium for dual-contrast MRI

    SciTech Connect

    Zhang, Fan; Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 ; Huang, Xinglu; Qian, Chunqi; Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 ; Zhu, Lei; Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 ; Hida, Naoki; Niu, Gang; Chen, Xiaoyuan

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer MR contrast agents exert influence on T{sub 1} or T{sub 2} relaxation time of the surrounding tissue. Black-Right-Pointing-Pointer Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. Black-Right-Pointing-Pointer Dual contrast MRI enhances the delineation of tumor borders and small lesions. Black-Right-Pointing-Pointer The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd{sup 3+}. Black-Right-Pointing-Pointer The effect of DC-MRI can also come from the distinct pharmacokinetic distribution of SPIO and Gd-DTPA. -- Abstract: Purpose: The use of MR contrast agents allows accurate diagnosis by exerting an influence on the longitudinal (T{sub 1}) or transverse (T{sub 2}) relaxation time of the surrounding tissue. In this study, we combined the use of iron oxide (IO) particles and nonspecific extracellular gadolinium chelate (Gd) in order to further improve the sensitivity and specificity of lesion detection. Procedures: With a 7-Tesla scanner, pre-contrasted, IO-enhanced and dual contrast agent enhanced MRIs were performed in phantom, normal animals, and animal models of lymph node tumor metastases and orthotopic brain tumor. For the dual-contrast (DC) MRI, we focused on the evaluation of T{sub 2} weighted DC MRI with IO administered first, then followed by the injection of a bolus of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Results: Based on the C/N ratios and MRI relaxometry, the synergistic effect of coordinated administration of Gd-DTPA and IO was observed and confirmed in phantom, normal liver and tumor models. At 30 min after administration of Feridex, Gd-DTPA further decreased T{sub 2} relaxation in liver immediately after the injection. Additional administration of Gd-DTPA also immediately increased the signal contrast between tumor and brain parenchyma and maximized the C/N ratio to -4.12 {+-} 0.71. Dual contrast MRI also enhanced the delineation of tumor borders and small lesions. Conclusions: DC-MRI will be helpful to improve diagnostic accuracy and decrease the threshold size for lesion detection.

  12. Atherosclerotic plaque inflammation quantification using dynamic contrast-enhanced (DCE) MRI

    PubMed Central

    Wu, Tingting; Kerwin, William S.; Yuan, Chun

    2013-01-01

    Inflammation plays an important role in atherosclerosis. Given the increasing interest in using in-vivo imaging methods to study the physiology and treatment effects in atherosclerosis, noninvasive intraplaque inflammation quantitative method is needed. Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) has been proposed and validated to quantitatively characterize atherosclerotic plaque inflammation. Recent studies have optimized the imaging protocol, pharmacokinetic modeling techniques. All of these technical advances further promoted DCE-MRI to clinical investigations in plaque risk assessment and therapeutic response monitor. Although larger clinical studies are still needed, DCE-MRI has been proven to be a promising tool to reveal more about intraplaque inflammation by in vivo quantitative inflammation imaging. PMID:24404443

  13. Original Research Manganese-Enhanced MRI Reveals Multiple

    E-print Network

    Duong, Timothy Q.

    not cross the blood­retinal barrier and the retinal pigment epithelium-- further enhanced the two layers neurode- generative changes to structure in retinal diseases can be detected using MEMRI. Key Words the retinal pigment epithelium (RPE) and the sclera. If considered with the six histologically defined layers

  14. Dynamic Contrast-Enhanced MRI of Cervical Cancers: Temporal Percentile Screening of Contrast Enhancement Identifies Parameters for Prediction of Chemoradioresistance

    SciTech Connect

    Andersen, Erlend K.F.; Hole, Knut Hakon; Lund, Kjersti V.; Sundfor, Kolbein; Kristensen, Gunnar B.; Lyng, Heidi; Malinen, Eirik

    2012-03-01

    Purpose: To systematically screen the tumor contrast enhancement of locally advanced cervical cancers to assess the prognostic value of two descriptive parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Methods and Materials: This study included a prospectively collected cohort of 81 patients who underwent DCE-MRI with gadopentetate dimeglumine before chemoradiotherapy. The following descriptive DCE-MRI parameters were extracted voxel by voxel and presented as histograms for each time point in the dynamic series: normalized relative signal increase (nRSI) and normalized area under the curve (nAUC). The first to 100th percentiles of the histograms were included in a log-rank survival test, resulting in p value and relative risk maps of all percentile-time intervals for each DCE-MRI parameter. The maps were used to evaluate the robustness of the individual percentile-time pairs and to construct prognostic parameters. Clinical endpoints were locoregional control and progression-free survival. The study was approved by the institutional ethics committee. Results: The p value maps of nRSI and nAUC showed a large continuous region of percentile-time pairs that were significantly associated with locoregional control (p < 0.05). These parameters had prognostic impact independent of tumor stage, volume, and lymph node status on multivariate analysis. Only a small percentile-time interval of nRSI was associated with progression-free survival. Conclusions: The percentile-time screening identified DCE-MRI parameters that predict long-term locoregional control after chemoradiotherapy of cervical cancer.

  15. Enhanced basal and disorderly growth hormone secretion distinguish acromegalic from normal pulsatile growth hormone release.

    PubMed Central

    Hartman, M L; Pincus, S M; Johnson, M L; Matthews, D H; Faunt, L M; Vance, M L; Thorner, M O; Veldhuis, J D

    1994-01-01

    Pulses of growth hormone (GH) release in acromegaly may arise from hypothalamic regulation or from random events intrinsic to adenomatous tissue. To distinguish between these possibilities, serum GH concentrations were measured at 5-min intervals for 24 h in acromegalic men and women with active (n = 19) and inactive (n = 9) disease and in normal young adults in the fed (n = 20) and fasted (n = 16) states. Daily GH secretion rates, calculated by deconvolution analysis, were greater in patients with active acromegaly than in fed (P < 0.05) but not fasted normal subjects. Significant basal (nonpulsatile) GH secretion was present in virtually all active acromegalics but not those in remission or in fed and fasted normal subjects. A recently introduced scale- and model-independent statistic, approximate entropy (ApEn), was used to test for regularity (orderliness) in the GH data. All but one acromegalic had ApEn values greater than the absolute range in normal subjects, indicating reduced orderliness of GH release; ApEn distinguished acromegalic from normal GH secretion (fed, P < 10(-12); fasted, P < 10(-7)) with high sensitivity (95%) and specificity (100%). Acromegalics in remission had ApEn scores larger than those of normal subjects (P < 0.0001) but smaller than those of active acromegalics (P < 0.001). The coefficient of variation of successive incremental changes in GH concentrations was significantly lower in acromegalics than in normal subjects (P < 0.001). Fourier analysis in acromegalics revealed reduced fractional amplitudes compared to normal subjects (P < 0.05). We conclude that GH secretion in acromegaly is highly irregular with disorderly release accompanying significant basal secretion. Images PMID:8083369

  16. Intraoperative detection of glioma invasion beyond MRI enhancement with Raman spectroscopy in humans

    NASA Astrophysics Data System (ADS)

    Jermyn, Michael; Mok, Kelvin; Mercier, Jeanne; Desroches, Joannie; Pichette, Julien; Saint-Arnaud, Karl; Guiot, Marie-Christine; Petrecca, Kevin; Leblond, Frédéric

    2015-03-01

    Cancer tissue is frequently impossible to distinguish from normal brain during surgery. Gliomas are a class of brain cancer which invade into the normal brain. If left unresected, these invasive cancer cells are the source of glioma recurrence. Moreover, these invasion areas do not show up on standard-of-care pre-operative Magnetic Resonance Imaging (MRI). This inability to fully visualize invasive brain cancers results in subtotal surgical resections, negatively impacting patient survival. To address this issue, we have demonstrated the efficacy of single-point in vivo Raman spectroscopy using a contact hand-held fiber optic probe for rapid detection of cancer invasion in 8 patients with low and high grade gliomas. Using a supervised machine learning algorithm to analyze the Raman spectra obtained in vivo, we were able to distinguish normal brain from the presence of cancer cells with sensitivity and specificity greater than 90%. Moreover, by correlating these results with pre-operative MRI we demonstrate the ability to detect low density cancer invasion up to 1.5cm beyond the cancer extent visible using MRI. This represents the potential for significant improvements in progression-free and overall patient survival, by identifying previously undetectable residual cancer cell populations and preventing the resection of normal brain tissue. While the importance of maximizing the volume of tumor resection is important for all grades of gliomas, the impact for low grade gliomas can be dramatic because surgery can even be curative. This convenient technology can rapidly classify cancer invasion in real-time, making it ideal for intraoperative use in brain tumor resection.

  17. Assessment of blood–brain barrier disruption using dynamic contrast-enhanced MRI. A systematic review

    PubMed Central

    Heye, Anna K.; Culling, Ross D.; Valdés Hernández, Maria del C.; Thrippleton, Michael J.; Wardlaw, Joanna M.

    2014-01-01

    There is increasing recognition of the importance of blood–brain barrier (BBB) disruption in aging, dementia, stroke and multiple sclerosis in addition to more commonly-studied pathologies such as tumors. Dynamic contrast-enhanced MRI (DCE-MRI) is a method for studying BBB disruption in vivo. We review pathologies studied, scanning protocols and data analysis procedures to determine the range of available methods and their suitability to different pathologies. We systematically review the existing literature up to February 2014, seeking studies that assessed BBB integrity using T1-weighted DCE-MRI techniques in animals and humans in normal or abnormal brain tissues. The literature search provided 70 studies that were eligible for inclusion, involving 417 animals and 1564 human subjects in total. The pathologies most studied are intracranial neoplasms and acute ischemic strokes. There are large variations in the type of DCE-MRI sequence, the imaging protocols and the contrast agents used. Moreover, studies use a variety of different methods for data analysis, mainly based on model-free measurements and on the Patlak and Tofts models. Consequently, estimated KTrans values varied widely. In conclusion, DCE-MRI is shown to provide valuable information in a large variety of applications, ranging from common applications, such as grading of primary brain tumors, to more recent applications, such as assessment of subtle BBB dysfunction in Alzheimer's disease. Further research is required in order to establish consensus-based recommendations for data acquisition and analysis and, hence, improve inter-study comparability and promote wider use of DCE-MRI. PMID:25379439

  18. Casein-coated Iron Oxide Nanoparticles for High MRI Contrast Enhancement and Efficient Cell Targeting

    PubMed Central

    Huang, Jing; Wang, Liya; Lin, Run; Wang, Andrew Y.; Yang, Lily; Kuang, Min; Qian, Weiping; Mao, Hui

    2013-01-01

    Surface properties, as well as inherent physicochemical properties, of the engineered nanomaterials play important roles in their interactions with the biological systems, which eventually affect their efficiency in diagnostic and therapeutic applications. Here we report a new class MRI contrast agent based on milk casein protein coated iron oxide nanoparticles (CNIOs) with a core size of 15 nm and hydrodynamic diameter ~30 nm. These CNIOs exhibited excellent water-solubility, colloidal stability, and biocompatibility. Importantly, CNIOs exhibited prominent T2 enhancing capability with a transverse relaxivity r2 of 273 mM?1s?1 at 3 Tesla. The transverse relaxivity is ~2.5-fold higher than that of iron oxide nanoparticles with the same core but an amphiphilic polymer coating. CNIOs showed pH-responsive properties, formed loose and soluble aggregates near the pI (pH~4.0). The aggregates could be dissociated reversibly when the solution pH was adjusted away from the pI. The transverse relaxation property and MRI contrast enhancing effect of CNIOs remained unchanged in the pH range of 2.0 to 8.0. Further functionalization of CNIOs can be achieved via surface modification of the protein coating. Bio-affinitive ligands, such as a single chain fragment from the antibody of epidermal growth factor receptor (ScFvEGFR), could be readily conjugated onto the protein coating, enabling specific targeting to MDA-MB-231 breast cancer cells over-expressing EGFR. T2-weighted MRI of mice intravenously administered with CNIOs demonstrated strong contrast enhancement in the liver and spleen. These favorable properties suggest CNIOs as a class of biomarker targeted magnetic nanoparticles for MRI contrast enhancement and related biomedical applications. PMID:23633522

  19. Multifunctional nanoparticle platforms for in vivo MRI enhancement and photodynamic therapy of a rat brain cancer

    NASA Astrophysics Data System (ADS)

    Kopelman, Raoul; Lee Koo, Yong-Eun; Philbert, Martin; Moffat, Bradford A.; Ramachandra Reddy, G.; McConville, Patrick; Hall, Daniel E.; Chenevert, Thomas L.; Bhojani, Mahaveer Swaroop; Buck, Sarah M.; Rehemtulla, Alnawaz; Ross, Brian D.

    2005-05-01

    A paradigm for brain cancer detection, treatment, and monitoring is established. Multifunctional biomedical nanoparticles (30-60 nm) containing photosensitizer externally deliver reactive oxygen species (ROS) to cancer cells while simultaneously enhancing magnetic resonance imaging (MRI) contrast providing real-time tumor kill measurement. Plasma residence time control and specific cell targeting are achieved. A 5 min treatment in rats halted and even reversed in vivo tumor growth after 3-4 days post-treatment.

  20. Statistical mapping of sound-evoked activity in the mouse auditory midbrain using Mn-enhanced MRI

    E-print Network

    10 August 2007 Available online 29 August 2007 Manganese-enhanced MRI (MEMRI) has been developed adaptation in retinal neurons (Berkowitz et al., 2006), to map cocaine-induced neuronal activation (Lu et al

  1. Semi-Automated Volumetric Quantification of Tumor Necrosis in Soft Tissue Sarcoma Using Contrast Enhanced MRI

    PubMed Central

    MONSKY, WAYNE L.; JIN, BEDRO; MOLLOY, CHRIS; CANTER, ROBERT J.; LI, CHIN SHANG; LIN, TC; BORYS, DANIEL; MACK, WALTER; KIM, ISAAC; BUONOCORE, MICHAEL H.; CHAUDHARI, ABHIJIT J.

    2014-01-01

    Background Response Evaluation Criteria in Solid Tumors (RECIST) defined measurements are limited when evaluating soft tissue sarcoma (STS) response to therapy. Histopathologic assessment of STS response requires a determination of necrosis following resection. A novel semiautomated technique for volumetric measurement of tumor necrosis, using enhanced magnetic resonance imaging (CE-MRI), is described. Patients and Methods Eighteen patients with STS were treated with neoadjuvant therapy and then resected. CE-MRI, obtained prior to resection, were evaluated by two observers using semi-automated segmentation. Tumor volume and percent necrosis was compared with histology and RECIST measurements. Results The median percent necrosis, determined histologically and from CE-MRI, was 71.9% and 67.8%, respectively. Accuracy of these semiautomated measurements was confirmed, being statistically similar to those obtained at histopathologic assessment of the resected tumor. High Intra-class correlation coefficients suggest good inter-observer reproducibility. Tumor necrosis did not correlate with RECIST measurements. Conclusion Semi-automated determination of tumor volume and necrosis, using CE-MRI, is suggested to be accurate and reproducible. PMID:23155265

  2. Enhanced brain connectivity in math-gifted adolescents: An fMRI study using mental rotation.

    PubMed

    Prescott, James; Gavrilescu, Maria; Cunnington, Ross; O'Boyle, Michael W; Egan, Gary F

    2010-12-01

    Mathematical giftedness is a form of intelligence related to enhanced mathematical reasoning that can be tested using a variety of numerical and spatial tasks. A number of neurobiological mechanisms related to exceptional mathematical reasoning ability have been postulated, including enhanced brain connectivity. We aimed to further investigate this possibility by comparing a group of mathematically gifted adolescents with an average math ability control group performing mental rotation of complex three-dimensional block figures. Functional magnetic resonance imaging (fMRI) data were collected and differences in intrahemispheric and interhemispheric connectivity between the groups were assessed using structural equation modeling (SEM). The math-gifted showed heightened intrahemispheric frontoparietal connectivity, as well as enhanced interhemispheric frontal connectivity between the dorsolateral prefrontal and premotor cortex. These enhanced connectivity patterns are consistent with previous studies linking increased activation of the frontal and parietal regions with high fluid intelligence, and may be a unique neural characteristic of the mathematically gifted brain. PMID:24168381

  3. Neural Correlates of Feigned Memory Impairment are Distinguishable from Answering Randomly and Answering Incorrectly: An fMRI and Behavioral Study

    ERIC Educational Resources Information Center

    Liang, Chun-Yu; Xu, Zhi-Yuan; Mei, Wei; Wang, Li-Li; Xue, Li; Lu, De Jian; Zhao, Hu

    2012-01-01

    Previous functional magnetic resonance imaging (fMRI) studies have identified activation in the prefrontal-parietal-sub-cortical circuit during feigned memory impairment when comparing with truthful telling. Here, we used fMRI to determine whether neural activity can differentiate between answering correctly, answering randomly, answering…

  4. A corrole nanobiologic elicits tissue-activated MRI contrast enhancement and tumor-targeted toxicity.

    PubMed

    Sims, Jessica D; Hwang, Jae Youn; Wagner, Shawn; Alonso-Valenteen, Felix; Hanson, Chris; Taguiam, Jan Michael; Polo, Richard; Harutyunyan, Ira; Karapetyan, Gevorg; Sorasaenee, Karn; Ibrahim, Ahmed; Marban, Eduardo; Moats, Rex; Gray, Harry B; Gross, Zeev; Medina-Kauwe, Lali K

    2015-11-10

    Water-soluble corroles with inherent fluorescence can form stable self-assemblies with tumor-targeted cell penetration proteins, and have been explored as agents for optical imaging and photosensitization of tumors in pre-clinical studies. However, the limited tissue-depth of excitation wavelengths limits their clinical applicability. To examine their utility in more clinically-relevant imaging and therapeutic modalities, here we have explored the use of corroles as contrast enhancing agents for magnetic resonance imaging (MRI), and evaluated their potential for tumor-selective delivery when encapsulated by a tumor-targeted polypeptide. We have found that a manganese-metallated corrole exhibits significant T1 relaxation shortening and MRI contrast enhancement that is blocked by particle formation in solution but yields considerable MRI contrast after tissue uptake. Cell entry but not low pH enables this. Additionally, the corrole elicited tumor-toxicity through the loss of mitochondrial membrane potential and cytoskeletal breakdown when delivered by the targeted polypeptide. The protein-corrole particle (which we call HerMn) exhibited improved therapeutic efficacy compared to current targeted therapies used in the clinic. Taken together with its tumor-preferential biodistribution, our findings indicate that HerMn can facilitate tumor-targeted toxicity after systemic delivery and tumor-selective MR imaging activatable by internalization. PMID:26334483

  5. Added value of diffusion-weighted MRI in detection of cervical cancer recurrence: comparison with morphologic and dynamic contrast-enhanced MRI sequences

    PubMed Central

    Lucas, Rita; Dias, João Lopes; Cunha, Teresa Margarida

    2015-01-01

    PURPOSE We aimed to evaluate the added value of diffusion-weighted imaging (DWI) to standard magnetic resonance imaging (MRI) for detecting post-treatment cervical cancer recurrence. The detection accuracy of T2-weighted (T2W) images was compared with that of T2W MRI combined with either dynamic contrast-enhanced (DCE) MRI or DWI. METHODS Thirty-eight women with clinically suspected uterine cervical cancer recurrence more than six months after treatment completion were examined with 1.5 Tesla MRI including T2W, DCE, and DWI sequences. Disease was confirmed histologically and correlated with MRI findings. The diagnostic performance of T2W imaging and its combination with either DCE or DWI were analyzed. Sensitivity, positive predictive value, and accuracy were calculated. RESULTS Thirty-six women had histologically proven recurrence. The accuracy for recurrence detection was 80% with T2W/DCE MRI and 92.1% with T2W/DWI. The addition of DCE sequences did not significantly improve the diagnostic ability of T2W imaging, and this sequence combination misclassified two patients as falsely positive and seven as falsely negative. The T2W/DWI combination revealed a positive predictive value of 100% and only three false negatives. CONCLUSION The addition of DWI to T2W sequences considerably improved the diagnostic ability of MRI. Our results support the inclusion of DWI in the initial MRI protocol for the detection of cervical cancer recurrence, leaving DCE sequences as an option for uncertain cases. PMID:26200480

  6. Description of focal liver lesions with Gd-EOB-DTPA enhanced MRI

    PubMed Central

    CARAIANI, COSMIN-NICOLAE; DAN, MARIAN; FENESAN, DIANA-IOANA; BADEA, RADU

    2015-01-01

    Imaging procedures play a fundamental role in the therapeutic management of focal liver lesions. The goals of imaging are to detect and correctly characterize focal liver lesions. This review highlights the performances of newer, liver-specific, contrast media in the diagnosis of focal liver lesions, particularly Gd-EOB-DTPA (Primovist), the most frequently used liver specific contrast media. It has been shown, in different papers, that Gd-EOB-DTPA has better performances compared to either triphasic contrast enhanced computed tomography or dynamic MRI in both detection and characterization of hepatocellular carcinoma on the cirrhotic liver. Therefore liver MRI with Primovist is considered, in many centers, the “state-of-the-art” imaging examination of the liver before surgery or liver transplantation. Gd-EOB-DTPA is also useful in the differential diagnosis of benign hypervascular focal liver lesions such as adenomas or focal nodular hyperplasias.

  7. fMRI feedback enhances emotion regulation as evidenced by a reduced amygdala response.

    PubMed

    Sarkheil, Pegah; Zilverstand, Anna; Kilian-Hütten, Niclas; Schneider, Frank; Goebel, Rainer; Mathiak, Klaus

    2015-03-15

    Deficits in emotion regulation are a prominent feature of psychiatric conditions and a promising target for treatment. For instance, cognitive reappraisal is regarded as an effective strategy for emotion regulation. Neurophysiological models have established the lateral prefrontal cortex (LPFC) as a key structure in the regulation of emotion processing through modulations of emotion-eliciting structures such as the amygdala. Feedback of the LPFC activity by real-time functional magnetic resonance (fMRI) may thus enhance the efficacy of cognitive reappraisal. During cognitive reappraisal of aversive visual stimuli, LPFC activity was fed back to the experimental group, whereas control participants received no such information. As a result, during reappraisal, amygdala activity was lower in the experimental group than in the controls. Furthermore, an increase of inter-hemispheric functional connectivity emerged in the feedback group. The current study extends the neurofeedback literature by suggesting that fMRI feedback can modify brain activity during a given task. PMID:25461265

  8. Quantification of fibrosis in infarcted swine hearts by ex vivo late gadolinium-enhancement and diffusion-weighted MRI methods

    NASA Astrophysics Data System (ADS)

    Pop, Mihaela; Ghugre, Nilesh R.; Ramanan, Venkat; Morikawa, Lily; Stanisz, Greg; Dick, Alexander J.; Wright, Graham A.

    2013-08-01

    Many have speculated that MRI signal characteristics can be used to identify regions of heterogeneous infarct associated with an arrhythmogenic substrate; however, direct evidence of this relationship is limited. The aim of this study was to demonstrate the remodelling characteristics of fibrosis by means of histology and high-resolution MR imaging. For this purpose, we performed whole-mount histology in heart samples (n = 9) collected from five swine at six weeks post-infarction and compared the extent of fibrosis in the infarcted areas delineated in these histological images with that obtained ex vivo by MRI using late gadolinium-enhancement (LGE) and diffusion-weighted imaging (DWI) methods. All MR images were obtained at a submillimetre resolution (i.e., voxel size of 0.6×0.6×1.2 mm3). Specifically, in the histology images, we differentiated moderate fibrosis (consisting of a mixture of viable and non-viable myocytes, known as border zone, BZ) from severe fibrosis (i.e., the dense scar). Correspondingly, tissue heterogeneities in the MR images were categorized by a Gaussian mixture model into healthy, BZ and scar. Our results showed that (a) both MRI methods were capable of qualitatively distinguishing sharp edges between dense scar and healthy tissue from regions of heterogeneous BZ; (b) the BZ and dense scar areas had intermediate-to-high increased values of signal intensity in the LGE images and of apparent diffusion coefficient in the DWI, respectively. In addition, as demonstrated by the Picrosirius Red and immunohistochemistry stains, the viable bundles in the BZ were clearly separated by thin collagen strands and had reduced expression of Cx43, whereas the core scar was composed of dense fibrosis. A quantitative analysis demonstrated that the comparison between BZ/scar extent in LGE and DWI to the corresponding areas identified in histology yielded very good correlations (i.e., for the scar identified by LGE, R2 was 0.96 compared to R2 = 0.93 for the scar identified in ADC maps, whereas the BZ had R2 = 0.95 for the correlation between LGE and histology compared to R2 = 0.91 obtained for ADC). This novel study represents an intermediate step in translating such research to the in vivo stages, as well as in establishing the best and most accurate MR method to help identify arrhythmia substrate in patients with structural heart disease.

  9. Dynamic contrast enhanced T1 MRI perfusion differentiates pseudoprogression from recurrent glioblastoma.

    PubMed

    Thomas, Alissa A; Arevalo-Perez, Julio; Kaley, Thomas; Lyo, John; Peck, Kyung K; Shi, Weiji; Zhang, Zhigang; Young, Robert J

    2015-10-01

    Pseudoprogression may present as transient new or increasing enhancing lesions that mimic recurrent tumors in treated glioblastoma. The purpose of this study was to examine the utility of dynamic contrast enhanced T1 magnetic resonance imaging (DCE MRI) in differentiating between pseudoprogression and tumor progression and devise a cut-off value sensitive for pseudoprogression. We retrospectively examined 37 patients with glioblastoma treated with radiation and temozolomide after surgical resection that then developed new or increasing enhancing lesion(s) indeterminate for pseudoprogression versus progression. Volumetric plasma volume (Vp) and time-dependent leakage constant (Ktrans) maps were measured for the enhancing lesion and the mean and ninetieth percentile histogram values recorded. Lesion outcome was determined by clinical follow up with pseudoprogression defined as stable disease not requiring new treatment. Statistical analysis was performed with Wilcoxon rank-sum tests. Patients with pseudoprogression (n = 13) had Vp (mean) = 2.4 and Vp (90 %tile) = 3.2; and Ktrans (mean) = 3.5 and Ktrans (90 %tile) = 4.2. Patients with tumor progression (n = 24) had Vp (mean) = 5.3 and Vp (90 %tile) = 6.6; and Ktrans (mean) = 7.4 and Ktrans (90 %tile) = 9.1. Compared with tumor progression, pseudoprogression demonstrated lower Vp perfusion values (p = 0.0002) with a Vp (mean) cutoff <3.7 yielding 85 % sensitivity and 79 % specificity for pseudoprogression. Ktrans (mean) of >3.6 had a 69 % sensitivity and 79 % specificity for disease progression. DCE MRI shows lower plasma volume and time dependent leakage constant values in pseudoprogression than in tumor progression. A cut-off value with high sensitivity for pseudoprogression can be applied to aid in interpretation of DCE MRI. PMID:26275367

  10. 2008 Fall : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Armstrong Jack Ray Highly Distinguished Arndt Tamara Lynn Highly Distinguished August Shelby Distinguished Boone Hunter Boatwright Highly Distinguished Booros Martha Highly Distinguished Bowen Jonathan

  11. Dynamic-contrast-enhanced-MRI with extravasating contrast reagent: Rat cerebral glioma blood volume determination

    NASA Astrophysics Data System (ADS)

    Li, Xin; Rooney, William D.; Várallyay, Csanád G.; Gahramanov, Seymur; Muldoon, Leslie L.; Goodman, James A.; Tagge, Ian J.; Selzer, Audrey H.; Pike, Martin M.; Neuwelt, Edward A.; Springer, Charles S.

    2010-10-01

    The accurate mapping of the tumor blood volume (TBV) fraction ( vb) is a highly desired imaging biometric goal. It is commonly thought that achieving this is difficult, if not impossible, when small molecule contrast reagents (CRs) are used for the T1-weighted (Dynamic-Contrast-Enhanced) DCE-MRI technique. This is because angiogenic malignant tumor vessels allow facile CR extravasation. Here, a three-site equilibrium water exchange model is applied to DCE-MRI data from the cerebrally-implanted rat brain U87 glioma, a tumor exhibiting rapid CR extravasation. Analyses of segments of the (and the entire) DCE data time-course with this "shutter-speed" pharmacokinetic model, which admits finite water exchange kinetics, allow TBV estimation from the first-pass segment. Pairwise parameter determinances were tested with grid searches of 2D parametric error surfaces. Tumor blood volume ( vb), as well as ve (the extracellular, extravascular space volume fraction), and Ktrans (a CR extravasation rate measure) parametric maps are presented. The role of the Patlak Plot in DCE-MRI is also considered.

  12. Semi-quantitative assessment of pulmonary perfusion in children using dynamic contrast-enhanced MRI

    NASA Astrophysics Data System (ADS)

    Fetita, Catalin; Thong, William E.; Ou, Phalla

    2013-03-01

    This paper addresses the study of semi-quantitative assessment of pulmonary perfusion acquired from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in a study population mainly composed of children with pulmonary malformations. The automatic analysis approach proposed is based on the indicator-dilution theory introduced in 1954. First, a robust method is developed to segment the pulmonary artery and the lungs from anatomical MRI data, exploiting 2D and 3D mathematical morphology operators. Second, the time-dependent contrast signal of the lung regions is deconvolved by the arterial input function for the assessment of the local hemodynamic system parameters, ie. mean transit time, pulmonary blood volume and pulmonary blood flow. The discrete deconvolution method implements here a truncated singular value decomposition (tSVD) method. Parametric images for the entire lungs are generated as additional elements for diagnosis and quantitative follow-up. The preliminary results attest the feasibility of perfusion quantification in pulmonary DCE-MRI and open an interesting alternative to scintigraphy for this type of evaluation, to be considered at least as a preliminary decision in the diagnostic due to the large availability of the technique and to the non-invasive aspects.

  13. DCE@urLAB: a dynamic contrast-enhanced MRI pharmacokinetic analysis tool for preclinical data

    PubMed Central

    2013-01-01

    Background DCE@urLAB is a software application for analysis of dynamic contrast-enhanced magnetic resonance imaging data (DCE-MRI). The tool incorporates a friendly graphical user interface (GUI) to interactively select and analyze a region of interest (ROI) within the image set, taking into account the tissue concentration of the contrast agent (CA) and its effect on pixel intensity. Results Pixel-wise model-based quantitative parameters are estimated by fitting DCE-MRI data to several pharmacokinetic models using the Levenberg-Marquardt algorithm (LMA). DCE@urLAB also includes the semi-quantitative parametric and heuristic analysis approaches commonly used in practice. This software application has been programmed in the Interactive Data Language (IDL) and tested both with publicly available simulated data and preclinical studies from tumor-bearing mouse brains. Conclusions A user-friendly solution for applying pharmacokinetic and non-quantitative analysis DCE-MRI in preclinical studies has been implemented and tested. The proposed tool has been specially designed for easy selection of multi-pixel ROIs. A public release of DCE@urLAB, together with the open source code and sample datasets, is available at http://www.die.upm.es/im/archives/DCEurLAB/. PMID:24180558

  14. 2009 Spring : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kunkle, Tom

    Highly Distinguished Beidler Katilyn V. Highly Distinguished Bellin Christina J Highly Distinguished Distinguished Bishop Jessica Lyin Highly Distinguished Black Karen Naomi Highly Distinguished Blackshaw Aaron Michael Highly Distinguished Blatterman Victoria Denny Highly Distinguished Blitz Jocelyn Helena Highly

  15. 2011 Spring : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Breazeale James Wharton Highly Distinguished Briner Clarissa Ann Highly Distinguished Brisini John Distinguished Brotherton Cara Price Highly Distinguished Brown Anna Laughlin Highly Distinguished Brown Chloe Alix Highly Distinguished Brown Kelsey Michelle Highly Distinguished Brown Kyle Truman Highly

  16. Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI

    NASA Astrophysics Data System (ADS)

    Sreeja, V.; Jayaprabha, K. N.; Joy, P. A.

    2015-04-01

    Superparamagnetic iron oxide nanoparticles of size ~5 nm surface functionalized with ascorbic acid (vitamin C) form a stable dispersion in water with a hydrodynamic size of ~30 nm. The anti-oxidant property of ascorbic acid is retained after capping, as evidenced from the capability of converting methylene blue to its reduced leuco form. NMR relaxivity studies show that the ascorbic-acid-coated superparamagnetic iron oxide aqueous nanofluid is suitable as a contrast enhancement agent for MRI applications, coupled with the excellent biocompatibility and medicinal values of ascorbic acid.

  17. Enhancement of NMR and MRI in the presence of hyperpolarized noble gases

    DOEpatents

    Pines, Alexander; Budinger, Thomas; Navon, Gil; Song, Yi-Qiao; Appelt, Stephan; Bifone, Angelo; Taylor, Rebecca; Goodson, Boyd; Seydoux, Roberto; Room, Toomas; Pietrass, Tanja

    2004-11-16

    The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

  18. Imaging Modalities for Assessment of Treatment Response to Nonsurgical Hepatocellular Carcinoma Therapy: Contrast-Enhanced US, CT, and MRI

    PubMed Central

    Minami, Yasunori; Kudo, Masatoshi

    2015-01-01

    Tumor response and time to progression have been considered pivotal for surrogate assessment of treatment efficacy for patients with hepatocellular carcinoma (HCC). Recent advancements in imaging modalities such as contrast-enhanced ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) are playing an important role in assessing the therapeutic effects of HCC treatments. According to some HCC clinical guidelines, post-therapeutic evaluation of HCC patients is based exclusively on contrast-enhanced dynamic imaging criteria. The recommended techniques are contrast-enhanced CT or contrast-enhanced MRI. Contrast-enhanced US is employed more in the positive diagnosis of HCC than in post-therapeutic monitoring. Although contrast enhancement is an important finding on imaging, enhancement does not necessarily depict the same phenomenon across modalities. We need to become well acquainted with the characteristics of each modality, including not only contrast-enhanced CT and MRI but also contrast-enhanced US. Many nonsurgical treatment options are now available for unresectable HCC, and accurate assessment of tumor response is essential to achieve favorable outcomes. For the assessment of successful radiofrequency ablation (RFA), the achievement of a sufficient ablation margin as well the absence of tumor vascular enhancement is essential. To evaluate the response to transcatheter arterial chemoembolization (TACE), enhanced tumor shrinkage is relied on as a measure of antitumor activity. Here, we give an overview of the current status of imaging assessment of HCC response to nonsurgical treatments including RFA and TACE. PMID:26697413

  19. Mn Enhancement and Respiratory Gating for In Utero MRI of the Embryonic Mouse Central Nervous System

    PubMed Central

    Deans, Abby E.; Wadghiri, Youssef Zaim; Berrios-Otero, César A.; Turnbull, Daniel H.

    2009-01-01

    The mouse is the preferred model organism for genetic studies of mammalian brain development. MRI has potential for in utero studies of mouse brain development, but has been limited previously by challenges of maximizing image resolution and contrast while minimizing artifacts due to physiological motion. Manganese (Mn)-enhanced MRI (MEMRI) studies have demonstrated central nervous system (CNS) contrast enhancement in mice from the earliest postnatal stages. The purpose of this study was to expand MEMRI to in utero studies of the embryonic CNS in combination with respiratory gating to decrease motion artifacts. We investigated MEMRI-facilitated CNS segmentation and three-dimensional (3D) analysis in wild-type mouse embryos from midgestation, and explored effects of Mn on embryonic survival and image contrast. Motivated by observations that MEMRI provided an effective method for visualization and volumetric analysis of embryonic CNS structures, especially in ventral regions, we used MEMRI to examine Nkx2.1 mutant mice that were previously reported to have ventral forebrain defects. Quantitative MEMRI analysis of Nkx2.1 knockout mice demonstrated volumetric changes in septum (SE) and basal ganglia (BG), as well as alterations in hypothalamic structures. This method may provide an effective means for in utero analysis of CNS phenotypes in a variety of mouse mutants. PMID:18506798

  20. Relationship between diffusion parameters derived from intravoxel incoherent motion MRI and perfusion measured by dynamic contrast-enhanced MRI of soft tissue tumors.

    PubMed

    Marzi, Simona; Stefanetti, Linda; Sperati, Francesca; Anelli, Vincenzo

    2016-01-01

    Our aim was to evaluate the link between diffusion parameters measured by intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and the perfusion metrics obtained with dynamic contrast-enhanced (DCE) MRI in soft tissue tumors (STTs). Twenty-eight patients affected by histopathologically confirmed STT were included in a prospective study. All patients underwent both DCE MRI and IVIM DWI. The perfusion fraction f, diffusion coefficient D and perfusion-related diffusion coefficient D* were estimated using a bi-exponential function to fit the DWI data. DCE MRI was acquired with a temporal resolution of 3-5?s. Maps of the initial area under the gadolinium concentration curve (IAUGC), time to peak (TTP) and maximum slope of increase (MSI) were derived using commercial software. The relationships between the DCE MRI and IVIM DWI measurements were assessed by Spearman's test. To exclude false positive results under multiple testing, the false discovery rate (FDR) procedure was applied. The Mann-Whitney test was used to evaluate the differences between all variables in patients with non-myxoid and myxoid STT. No significant relationship was found between IVIM parameters and any DCE MRI parameters. Higher f and D*f values were found in non-myxoid tumors compared with myxoid tumors (p?=?0.004 and p?=?0.003, respectively). MSI was significantly higher in non-myxoid tumors than in myxoid tumors (p?=?0.029). From the visual assessments of single clinical cases, both f and D*f maps were in satisfactory agreement with DCE maps in the extreme cases of an avascular mass and a highly vascularized mass, whereas, for tumors with slight vascularity or with a highly heterogeneous perfusion pattern, this association was not straightforward. Although IVIM DWI was demonstrated to be feasible in STT, our data did not support evident relationships between perfusion-related IVIM parameters and perfusion measured by DCE MRI. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26602061

  1. 2014 Spring : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kunkle, Tom

    Coulter Highly Distinguished Akasaka Haruna Highly Distinguished Akerley Tori Lisa Highly Distinguished Boyle Kathryn Grace Highly Distinguished Branin Carter Elizabeth Highly Distinguished Brelsford Mary

  2. 2010 Fall : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Bellin Christina J Highly Distinguished Bellomy Jennifer Roxzine Highly Distinguished Bemis Binda Rachel Anne Highly Distinguished Bing Alexandra Chan Highly Distinguished Bishop Anna Laurel Blackshaw Aaron Michael Highly Distinguished Blackwell Evan Robert Highly Distinguished 2 #12;2010 Fall

  3. 2009 Fall : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kunkle, Tom

    Distinguished Arber Noah Nachama Highly Distinguished Arjomand Sanaz Afrooz Highly Distinguished Armstrong Jack Beeland Cecil B Highly Distinguished Beidler Brien Hunter Highly Distinguished Beidler Katilyn V. Highly Todd Highly Distinguished Bonanno Alicia Marie Highly Distinguished Boone Hunter Boatwright Highly

  4. Toward Clinical Application of Manganese-enhanced MRI of Retinal Function

    PubMed Central

    Tofts, Paul S; Porchia, Andre; Jin, Ying; Roberts, Robin; Berkowitz, Bruce A

    2009-01-01

    Purpose The application of Manganese-Enhanced MRI (MEMRI) to measure retinal function in humans is unclear. To begin to address this gap, we tested the hypothesis that an FDA-approved manganese-based MRI contrast agent, Teslascan, is useful for measuring functional intraretinal ionic regulation. Methods Anesthetized dark- or light-adapted male healthy Sprague Dawley rats were infused for 30 min with 10 ?mol/kg of Teslascan (clinically relevant dose; n=5), 100 ?mol/kg Teslascan (n=5), or saline (n=5). Four hours post administration, high resolution MEMRI data were collected. Intraretinal signal intensities and enhancements were measured. Modelling was performed to estimate apparent retinal transfer constant Ki and to determine optimal data acquisition parameters. Results In light-adapted rats, intraretinal enhancements responded in a dose-response manner. In addition, in the outer retina the effect of light-adaptation was to reduce significantly Mn2+ uptake and Ki compared to dark-adaptation. A non-significant change was also observed in the inner retina. Modelling shows Mn2+ plasma concentration reaching a plateau after about 2 hours. Apparent Ki values for the clinically-relevant dose are 3-6 10-3 min-1, decreasing to 0.5-0.6 10-3 min-1 at the higher dose. Intraretinal signal is almost linear with Ki. Optimal TR for a spin echo sequence is 0.4-1.4s. Conclusion First time evidence is presented that a clinically-relevant dose and route of Teslascan can be used to measure intraretinal function. The potential for future clinical application of MEMRI in a broad range of retinopathies is high. PMID:19524028

  5. Diffuse Infantile Hepatic Hemangioendothelioma With Early Central Enhancement in an Adult: A Case Report of CT and MRI Findings.

    PubMed

    Dong, Aisheng; Dong, Hui; Zuo, Changjing; He, Tianlin

    2015-12-01

    Infantile hepatic hemangioendothelioma (IHH) is the most common vascular tumor of the liver in infancy. Adult with IHH is extremely rare. We presented a diffuse IHH in an adult patient with computed tomography (CT) and magnetic resonance image (MRI) findings.A 39-year-old man was admitted to our hospital because of a 2-year history of abnormal liver function tests and a 7-day history of jaundice. Physical examination revealed enlarged liver. Unenhanced abdominal CT showed enlargement of the liver with diffuse hypodensity. Enhanced CT on the arterial phase revealed multiple centrally enhanced lesions diffusely involved the enlarged liver. The enhanced areas of the lesions became larger on the portal phase and all the lesions became homogeneous enhanced on the delayed phase. These lesions showed heterogeneously hyperintense on T2-weighted image, hypointense on T1-weighted image, and early centrally enhanced on dynamic gadolinium-enhanced MRI, with complete tumor enhancement after 180?s. The patient underwent orthotopic liver transplantation. IHH type 2 was confirmed by pathology. The patient died of tumor recurrence in the liver 4 months after transplantation.Unlike the previously described imaging appearances of IHH, this case showed diffuse nodules with early central enhancement on CT and MRI. Considering the importance of the ability to differentiate IHH from other hepatic tumors, radiologists should be aware of these imaging appearances to establish knowledge of the entire spectrum of IHH. PMID:26705232

  6. Collateral circulation formation determines the characteristic profiles of contrast-enhanced MRI in the infarcted myocardium of pigs

    PubMed Central

    Wang, Jian; Xiang, Bo; Lin, Hung-yu; Liu, Hong-yu; Freed, Darren; Arora, Rakesh C; Tian, Gang-hong

    2015-01-01

    Aim: To investigate the relationship between the collateral circulation and contrast-enhanced MR signal change for myocardial infarction (MI) in pigs. Methods: Pigs underwent permanent ligation of two diagonal branches of the left anterior descending artery. First-pass perfusion (FPP) MRI (for detecting myocardial perfusion abnormalities) and delayed enhancement (DE) MRI (for estimating myocardial infarction) using Gd-DTPA were performed at 2 h, 7 d and 4 weeks after the coronary occlusion. Myocardial blood flow (MBF) was evaluated using nonradioactive red-colored microspheres. Histological examination was performed to characterize the infarcts. Results: Acute MI performed at 2 h afterwards was characterized by hypoenhancement in both FPP- and DE-MRI, with small and almost unchanged FPP-signal intensity (SI) and DE-SI due to negligible MBF. Subacute MI detected 7 d afterwards showed small but significantly increaseing FPP-SI, and was visible as a sluggish hyperenhancement in DE-MRI with considerably higher DE-SI compared to the normal myocardium; the MBF approached the half-normal value. Chronic MI detected at 4 weeks afterwards showed increasing FPP-SI comparable to the normal myocardium, and a rapid hyperenhancement in DE-MRI with even higher DE-SI; the MBF was close to the normal value. The MBF was correlated with FPP-SI (r=+0.94, P<0.01) and with the peak DE-SI (r=+0.92, P<0.01) at the three MI stages. Remodeled vessels were observed at intra-infarction and peri-infarction zones during the subacute and chronic periods. Conclusion: Progressive collateral recovery determines the characteristic profiles of contrast-enhanced MRI in acute, subacute and chronic myocardial infarction in pigs. The FPP- and DE-MRI signal profiles not only depend on the loss of tissue viability and enlarged interstitial space, but also on establishing a collateral circulation. PMID:25832427

  7. In vivo auditory brain mapping in mice with Mn-enhanced MRI

    PubMed Central

    Yu, Xin; Wadghiri, Youssef Zaim; Sanes, Dan H; Turnbull, Daniel H

    2007-01-01

    There are currently no noninvasive imaging methods available for auditory brain mapping in mice, despite the increasing use of genetically engineered mice to study auditory brain development and hearing loss. We developed a manganese-enhanced MRI (MEMRI) method to map regions of accumulated sound-evoked activity in awake, normally behaving mice. To demonstrate its utility for high-resolution (100-?m) brain mapping, we used MEMRI to show the tonotopic organization of the mouse inferior colliculus. To test its efficacy in an experimental setting, we acquired data from mice experiencing unilateral conductive hearing loss at different ages. Larger and persistent changes in auditory brainstem activity resulted when hearing loss occurred before the onset of hearing, showing that early hearing loss biases the response toward the functional ear. Thus, MEMRI provides a sensitive and effective method for mapping the mouse auditory brainstem and has great potential for a range of functional neuroimaging studies in normal and mutant mice. PMID:15924136

  8. Efficiency of Non-Contrast-Enhanced Liver Imaging Sequences Added to Initial Rectal MRI in Rectal Cancer Patients

    PubMed Central

    Kwon, Gene-hyuk; Kim, Kyung Ah; Hwang, Seong Su; Park, Soo Youn; Kim, Hyun A.; Choi, Sun Young; Kim, Ji Woong

    2015-01-01

    Purpose The purpose of this study was to estimate the value of addition of liver imaging to initial rectal magnetic resonance imaging (MRI) for detection of liver metastasis and evaluate imaging predictors of a high risk of liver metastasis on rectal MRI. Methods We enrolled 144 patients who from October 2010 to May 2013 underwent rectal MRI with T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) (b values = 50, 500, and 900 s/mm2) of the liver and abdominopelvic computed tomography (APCT) for the initial staging of rectal cancer. Two reviewers scored the possibility of liver metastasis on different sets of liver images (T2WI, DWI, and combined T2WI and DWI) and APCT and reached a conclusion by consensus for different analytic results. Imaging features from rectal MRI were also analyzed. The diagnostic performances of CT and an additional liver scan to detect liver metastasis were compared. Multivariate logistic regression to determine independent predictors of liver metastasis among rectal MRI features and tumor markers was performed. This retrospective study was approved by the Institutional Review Board, and the requirement for informed consent was waived. Results All sets of liver images were more effective than APCT for detecting liver metastasis, and DWI was the most effective. Perivascular stranding and anal sphincter invasion were statistically significant for liver metastasis (p = 0.0077 and p = 0.0471), while extramural vascular invasion based on MRI (mrEMVI) was marginally significant (p = 0.0534). Conclusion The addition of non-contrast-enhanced liver imaging, particularly DWI, to initial rectal MRI in rectal cancer patients could facilitate detection of liver metastasis without APCT. Perivascular stranding, anal sphincter invasion, and mrEMVI detected on rectal MRI were important imaging predictors of liver metastasis. PMID:26348217

  9. Nanoparticle-Enhanced MRI to Evaluate Radiation Delivery to the Regional Lymphatics for Patients With Breast Cancer

    SciTech Connect

    MacDonald, Shannon M.; Harisinghani, Mukesh G.; Katkar, Amol; Napolitano, Brian; Wolfgang, John; Taghian, Alphonse G.

    2010-07-15

    Purpose: At present, radiation (RT) fields are based largely, and often solely, on bony anatomy. Recent efforts have been taken to better define lymphatic regions for RT planning. Lymphotrophic nanoparticle-enhanced MRI (LN-MRI) allows for accurate identification of malignant and benign lymph nodes. We sought to evaluate RT delivery to lymphatics for breast cancer using LN-MRI. Methods and Materials: Twenty-three patients with breast cancer underwent LN-MRI. MRIs were anatomically registered to a reference CT; benign and malignant lymph nodes were contoured. Standard RT fields were planned and dose calculated to prescribe 45-50 Gy. Lymphatic regions were contoured on CT. Coverage of LN-MRI lymph nodes by RT fields and contoured lymphatics were assessed. Results: Eighty-one percent of all lymph nodes defined by LN-MRI were covered by the 45-Gy isodose line; 82% of malignant and 79% of benign. The 50-Gy isodose line only encompassed 60% of LN-MRI defined lymph nodes-64% of malignant and 59% of benign. For nodal volumes contoured in the absence of a margin, 86% of actual lymph nodes were within contoured volumes. When a 5-mm expansion was added, 99% were included. Conclusions: LN-MRI is a useful tool to delineate the location of breast regional lymphatics. These results suggest less than desired coverage of lymph nodes using standard RT fields and that a margin may be advisable when defining nodal volumes by CT. The use of IMRT and RT in lieu of surgery makes accurate definition of the location of breast regional lymphatics of paramount importance.

  10. Gadolinium-enhanced MRI features of acute gouty arthritis on top of chronic gouty involvement in different joints.

    PubMed

    Emad, Yasser; Ragab, Yasser; El-Naggar, Ahmed; El-Shaarawy, Nashwa; Abd-Allah, Mayada A; Gamal, Rania M; Fathy, Ahmed; Hawass, Mona; Rasker, Johannes J

    2015-11-01

    The aims of the current study are to describe gadolinium-enhanced MRI features of an acute flare of established gouty arthritis in different joints and to examine a possible association between serum uric acid and MRI signs indicative of ongoing inflammation and/or structural joint damage as well as association with disease characteristics and laboratory findings. Twenty-seven male patients with established chronic gout agreed to participate, mean age 47.6 years, and mean disease duration in months 43.2 (±31.8). For all patients, detailed demographic, disease characteristics, and laboratory findings were obtained and correlated with MRI findings. In 27 patients with established gout, a total of 50 MRI studies were performed of the following joints: feet joints (n?=?23), ankles (n?=?18), knees (n?=?5), and hand and wrist joints (n?=?4). MRI revealed capsular thickening in 19 patients, bone marrow edema (BME) in 15, soft tissue edema (STE) in 20, joint effusion in 21, bone erosions in 17, cartilaginous erosions in 4, and tenosynovitis in 9 cases. In 17 cases, tophaceous lesions were found. Post contrast MRI showed synovial thickening in seven cases. Positive correlations were observed between serum uric acid levels and the following MRI findings: capsular thickening (r?=?0.552, p?=?0.003), BME (r?=?0.668, p???0.0001), STE (r?=?0.559, p?=?0.002), and tenosynovitis (r?=?0.513, p?=?0.006). Using MRI in chronic gout, important features can be detected like BME, minute cartilaginous erosions, and hypertrophic synovial inflammation in post contrast MR images. Serum uric acid (SUA) was positively correlated with capsular thickening, BME, STE, and tenosynovitis. PMID:25681072

  11. Dynamic contrast-enhanced MRI of anterior prostate cancer: morphometric assessment and correlation with radical prostatectomy findings.

    PubMed

    Lemaitre, Laurent; Puech, Philippe; Poncelet, Edouard; Bouyé, Sébastien; Leroy, Xavier; Biserte, Jacques; Villers, Arnauld

    2009-02-01

    The purpose of the study was to relate morphometric features of prostate cancers in the anterior compartment of the prostate by dynamic contrast-enhanced (DCE) MRI to subsequent histopathologic findings. We prospectively performed DCE-MRI before biopsy in patients with suspected prostate cancer and selected those showing both a suspicious lesion at MRI and positive biopsies in the anterior compartment of the gland. Tumor contours, margins, largest surface areas and volumes were assessed at MRI and histopathology, when available. Anterior compartment tumors were classified according to transition zone (TZ) boundaries with the peripheral zone (PZ) or with the anterior fibromuscular stroma (SFMA). Forty-three patients were included in this study [median PSA 12.7 ng/ml (3.6-72)]. Whole-mount radical prostatectomy specimens were available in 27 cases. Of the anterior cancers, 89% had ill-defined margins at T2-weighted MRI. Cancer location and contour established at MRI agreed well with histopathology in the 27 cases. Median largest surface area and volume were 1.38 cm(2) (0.35-5.82) and 1.01 cc (0.15-7.4) for MRI versus 1.86 cm(2) (0.2-14) and 2.84 cc (0.33-28.92) for histopathology with respective correlation coefficients (r(2)) of 0.73 and 0.69. The site of origin could be accurately determined for the 15 tumors of less than 3 cc. We found a good relationship between DCE-MRI and histopathology for localization, morphologic description and volume assessment of anterior prostate cancers. PMID:18758786

  12. Quantitative activation-induced manganese-enhanced MRI reveals severity of Parkinson’s disease in mice

    PubMed Central

    Kikuta, Satomi; Nakamura, Yukiyo; Yamamura, Yukio; Tamura, Atsushi; Homma, Noriyasu; Yanagawa, Yuchio; Tamura, Hajime; Kasahara, Jiro; Osanai, Makoto

    2015-01-01

    We demonstrate that activation-induced manganese-enhanced magnetic resonance imaging with quantitative determination of the longitudinal relaxation time (qAIM-MRI) reveals the severity of Parkinson’s disease (PD) in mice. We first show that manganese ion-accumulation depends on neuronal activity. A highly active region was then observed by qAIM-MRI in the caudate-putamen in PD-model mice that was significantly correlated to the severity of PD, suggesting its involvement in the expression of PD symptoms. PMID:26255701

  13. Investigating the Influence of Flip Angle and k-Space Sampling on Dynamic Contrast-Enhanced MRI Breast Examinations

    PubMed Central

    Ledger, Araminta E.W.; Borri, Marco; Pope, Romney J.E.; Scurr, Erica D.; Wallace, Toni; Richardson, Cheryl; Usher, Marianne; Allen, Steven; Wilson, Robin M.; Thomas, Karen; deSouza, Nandita M.; Leach, Martin O.; Schmidt, Maria A.

    2014-01-01

    Rationale and Objectives To retrospectively investigate the effect of flip angle (FA) and k-space sampling on the performance of dynamic contrast-enhanced (DCE-) magnetic resonance imaging (MRI) breast sequences. Materials and Methods Five DCE-MRI breast sequences were evaluated (10°, 14°, and 18° FAs; radial or linear k-space sampling), with 7–10 patients in each group (n = 45). All sequences were compliant with current technical breast screening guidelines. Contrast agent (CA) uptake curves were constructed from the right mammary artery for each examination. Maximum relative enhancement, Emax, and time-to-peak enhancement, Tmax, were measured and compared between protocols (analysis of variance and Mann–Whitney). For each sequence, calculated values of maximum relative enhancement, Ecalc, were derived from the Bloch equations and compared to Emax. Fat suppression performance (residual bright fat and chemical shift artifact) was rated for each examination and compared between sequences (Fisher exact tests). Results Significant differences were identified between DCE-MRI sequences. Emax increased significantly at higher FAs and with linear k-space sampling (P < .0001; P = .001). Radial protocols exhibited greater Tmax than linear protocols at FAs of both 14° (P = .025) and 18° (P < .0001), suggesting artificially flattened uptake curves. Good correlation was observed between Ecalc and Emax (r = 0.86). Fat suppression failure was more pronounced at an FA of 18° (P = .008). Conclusions This retrospective approach is validated as a tool to compare and optimize breast DCE-MRI sequences. Alterations in FA and k-space sampling result in significant differences in CA uptake curve shape which could potentially affect diagnostic interpretation. These results emphasize the need for careful parameter selection and greater standardization of breast DCE-MRI sequences. PMID:25179563

  14. Dynamic Contrast-Enhanced MRI Kinetics of Invasive Breast Cancer: A Potential Prognostic Marker for Radiation Therapy

    SciTech Connect

    Loiselle, Christopher R.; Eby, Peter R.; DeMartini, Wendy B.; Peacock, Sue M.S.; Bittner, Nathan; Lehman, Constance D.; Kim, Janice N.

    2010-04-15

    Purpose: Our goal was to determine the correlations between dynamic contrast-enhanced MRI (DCE-MRI) kinetics of breast cancers and axillary nodal status (ANS) which may have prognostic value in designing radiation therapy recommendations. Methods and Materials: A retrospective review identified 167 consecutive patients treated with external beam radiotherapy for invasive breast cancer from Jan 1, 2006 to Nov 1, 2007. Patients with DCE-MRI kinetic data from our institution who underwent axillary surgical staging prior to chemotherapy were included. ANS was assessed as positive or negative by pathology record review. For each primary cancer, maximum tumor diameter and kinetic values for initial peak enhancement (PE), percent initial rapid enhancement (RE), and percent delayed washout enhancement (WE) were measured with a computer-aided evaluation program. Univariate, multivariate, and receiver operating characteristic curve analyses were performed according to the ANS. Results: Forty-six patients met study criteria, with 32 (70%) node-negative and 14 (30%) node-positive patients. Median PE was significantly greater in node-positive patients (209%) than in node-negative patients (138%, p = 0.0027). Similarly, median RE was significantly greater in node-positive patients (57%) than in node-negative patients (27%, p = 0.0436). WE was not different between groups (p = 0.9524). Median maximum tumor diameter was greater in node-positive patients (26 mm) than in node-negative patients (15 mm, p = 0.015). Multivariate analysis showed that only PE trended toward significance (p = 0.18). Conclusions: DCE-MRI kinetics of primary breast cancers correlate with ANS. Multivariate analysis demonstrates the correlation is not due simply to underlying lesion size. If validated prospectively, DCE-MRI kinetics may aid as a tool in selecting patients or designing fields for radiation therapy.

  15. Correlation of histological findings from a large ciliochoroidal melanoma with CT perfusion and 3T MRI dynamic enhancement studies

    PubMed Central

    Pulido, Jose S; Campeau, Norbert G; Klotz, Ernst; Primak, Andrew N; Saba, Osama; Gunduz, Kaan; Cantrill, Herbert; Salomão, Diva; McCollough, Cynthia H

    2008-01-01

    Background The initial use of a 64-slice computed tomography (CT) scanner for obtaining quantitative perfusion data from a large ciliochoroidal melanoma, and correlation with 3T magnetic resonance imaging (MRI) dynamic enhancement and tumor histology. Methods The CT perfusion scan was performed using 80 kVp, 250 mA and 1-sec rotation time for 40 sec. The analysis was performed using commercial perfusion analysis software with a prototype 3-dimensional motion correction tool. Dynamic contrast-enhanced 3-Tesla MRI measured the kinetics of enhancement to estimate the vascular permeability. The time-dependent enhancement patterns were obtained using the average signal intensity using Functool analysis software. The involved globe was enucleated and microscopic evaluation of the tumor was performed. Results The perfusion parameters blood flow, blood volume and permeability surface area product in the affected eye determined by CT perfusion analysis were 118 ml/100 ml/min, 11.3 ml/100 ml and 48 ml/100 ml/min. Dynamic MRI enhancement showed maximal intensity increase of 111%. The neoplasm was a ciliochoroidal spindle cell melanoma which was mitotically active (13 mitoses/40 hpf). Vascular loops and arcades were present throughout the tumor. The patient developed metastases within 9 months of presentation. Conclusion Quantitative CT perfusion analysis of ocular tumors is feasible with motion correction software. PMID:19668716

  16. Reproducibility of Dynamic Contrast-Enhanced MRI in Renal Cell Carcinoma

    PubMed Central

    Wang, Haiyi; Su, Zihua; Ye, Huiyi; Xu, Xiao; Sun, Zhipeng; Li, Lu; Duan, Feixue; Song, Yuanyuan; Lambrou, Tryphon; Ma, Lin

    2015-01-01

    Abstract The objective of this study was to investigate the intra- and interobserver as well as scan–rescan reproducibility of quantitative parameters of renal cell carcinomas (RCCs) with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A total of 21 patients with clear cell RCCs (17 men, 4 woman; age 37–69 years, mean age 54.6 years, mean size, 5.0?±?2.2?cm) were prospectively recruited from September 2012 to November 2012. Patients underwent paired DCE-MRI studies on a 3.0 T MR system with an interval of 48 to 72 hours. The extended-Tofts model and population-based arterial input function were used to calculate kinetic parameters. Three observers defined the 2-dimensional whole-tumor region of interest at the slice with the maximum diameter of the RCC. Intraobserver and scan–rescan differences were assessed using paired t tests, whereas interobserver differences using two-way analysis of variance. Intra- and interobserver reproducibility and scan–rescan reproducibility were evaluated using within-subject coefficient of variation (wCoV) and intraclass correlation coefficient (ICC). There were no significant intra-, interobserver, or scan–rescan differences in parameters (all P?>?0.05). All ICCs for intra- and interobserver agreements were >0.75 (P?30%). DCE-MRI demonstrated good intra- and interobserver reproducibility and moderate to good scan–rescan performance in the assessment of RCC using Ktrans, Kep, and Ve as parameters under noncontinuous scanning mode. Vp showed poor reproducibility, and thus may not be suitable for this scanning protocol. PMID:26376399

  17. Practical Dynamic Contrast Enhanced MRI in Small Animal Models of Cancer: Data Acquisition, Data Analysis, and Interpretation

    PubMed Central

    Barnes, Stephanie L.; Whisenant, Jennifer G.; Loveless, Mary E.; Yankeelov, Thomas E.

    2012-01-01

    Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) consists of the continuous acquisition of images before, during, and after the injection of a contrast agent. DCE-MRI allows for noninvasive evaluation of tumor parameters related to vascular perfusion and permeability and tissue volume fractions, and is frequently employed in both preclinical and clinical investigations. However, the experimental and analytical subtleties of the technique are not frequently discussed in the literature, nor are its relationships to other commonly used quantitative imaging techniques. This review aims to provide practical information on the development, implementation, and validation of a DCE-MRI study in the context of a preclinical study (though we do frequently refer to clinical studies that are related to these topics). PMID:23105959

  18. Corticospinal Tract Tracing in the Marmoset with a Clinical Whole-Body 3T Scanner Using Manganese-Enhanced MRI

    PubMed Central

    Plas, Benjamin; Bolan, Faye; Boulanouar, Kader; Renaud, Luc; Darmana, Robert; Vaysse, Laurence; Vieu, Christophe; Loubinoux, Isabelle

    2015-01-01

    Manganese-enhanced MRI (MEMRI) has been described as a powerful tool to depict the architecture of neuronal circuits. In this study we investigated the potential use of in vivo MRI detection of manganese for tracing neuronal projections from the primary motor cortex (M1) in healthy marmosets (Callithrix Jacchus). We determined the optimal dose of manganese chloride (MnCl2) among 800, 400, 40 and 8nmol that led to manganese-induced hyperintensity furthest from the injection site, as specific to the corticospinal tract as possible, and that would not induce motor deficit. A commonly available 3T human clinical MRI scanner and human knee coil were used to follow hyperintensity in the corticospinal tract 24h after injection. A statistical parametric map of seven marmosets injected with the chosen dose, 8 nmol, showed the corticospinal tract and M1 connectivity with the basal ganglia, substantia nigra and thalamus. Safety was determined for the lowest dose that did not induce dexterity and grip strength deficit, and no behavioral effects could be seen in marmosets who received multiple injections of manganese one month apart. In conclusion, our study shows for the first time in marmosets, a reliable and reproducible way to perform longitudinal ME-MRI experiments to observe the integrity of the marmoset corticospinal tract on a clinical 3T MRI scanner. PMID:26398500

  19. Detection of Neovessels in Atherosclerotic Plaques of Rabbits using Dynamic Contrast Enhanced MRI and 18F-FDG PET

    PubMed Central

    Calcagno, Claudia; Cornily, Jean-Christophe; Hyafil, Fabien; Rudd, James H. F.; Briley-Saebo, Karen C.; Mani, Venkatesh; Goldschlager, Gregg; Machac, Josef; Fuster, Valentin; Fayad, Zahi A.

    2011-01-01

    Introduction The association of inflammatory cells and neovessels in atherosclerosis is considered a histological hallmark of high-risk active lesions. Therefore, the development and validation of noninvasive imaging techniques that allow for the detection of inflammation and neoangiogenesis in atherosclerosis would be of major clinical interest. Objective Our aim was to test two techniques, black blood dynamic contrast enhanced MRI (DCE-MRI) and 18-fluorine-fluorodeoxyglucose (18F-FDG) PET, to quantify inflammation expressed as plaque neovessels content in a rabbit model of atherosclerosis. Methods and Results Atherosclerotic plaques were induced in the aorta of ten rabbits by a combination of two endothelial abrasions and four months hyperlipidemic diet. Six rabbits underwent MRI during the injection of Gd-DTPA, while four rabbits were imaged after injection of 18F-FDG with PET. We found a positive correlation between neovessels count in atherosclerotic plaques and 1) Gd-DTPA uptake parameters evaluated by DCE-MRI (r = 0.89, p = 0.016) and 2) 18F-FDG uptake evaluated by PET (r = 0.5, p =0.103 after clustered robust, Huber-White, standard errors analysis). Conclusion DCE-MRI and 18F-FDG PET may allow for the evaluation of inflammation in atherosclerotic plaques of rabbits. These non-invasive imaging modalities could be proposed as clinical tools in the evaluation of lesion prognosis and monitoring of anti–angiogenic therapies. PMID:18467641

  20. Magic Angle–Enhanced MRI of Fibrous Microstructures in Sclera and Cornea With and Without Intraocular Pressure Loading

    PubMed Central

    Ho, Leon C.; Sigal, Ian A.; Jan, Ning-Jiun; Squires, Alexander; Tse, Zion; Wu, Ed X.; Kim, Seong-Gi; Schuman, Joel S.; Chan, Kevin C.

    2014-01-01

    Purpose. The structure and biomechanics of the sclera and cornea are central to several eye diseases such as glaucoma and myopia. However, their roles remain unclear, partly because of limited noninvasive techniques to assess their fibrous microstructures globally, longitudinally, and quantitatively. We hypothesized that magic angle–enhanced magnetic resonance imaging (MRI) can reveal the structural details of the corneoscleral shell and their changes upon intraocular pressure (IOP) elevation. Methods. Seven ovine eyes were extracted and fixed at IOP = 50 mm Hg to mimic ocular hypertension, and another 11 eyes were unpressurized. The sclera and cornea were scanned at different angular orientations relative to the main magnetic field inside a 9.4-Tesla MRI scanner. Relative MRI signal intensities and intrinsic transverse relaxation times (T2 and T2*) were determined to quantify the magic angle effect on the corneoscleral shells. Three loaded and eight unloaded tendon samples were scanned as controls. Results. At magic angle, high-resolution MRI revealed distinct scleral and corneal lamellar fibers, and light/dark bands indicative of collagen fiber crimps in the sclera and tendon. Magic angle enhancement effect was the strongest in tendon and the least strong in cornea. Loaded sclera, cornea, and tendon possessed significantly higher T2 and T2* than unloaded tissues at magic angle. Conclusions. Magic angle–enhanced MRI can detect ocular fibrous microstructures without contrast agents or coatings and can reveal their MR tissue property changes with IOP loading. This technique may open up new avenues for assessment of the biomechanical and biochemical properties of ocular tissues in aging and in diseases involving the corneoscleral shell. PMID:25103267

  1. Intravascular contrast agent-enhanced MRI measuring contrast clearance and tumor blood volume and the effects of vascular modifiers in an experimental tumor

    SciTech Connect

    Bentzen, Lise . E-mail: lise@oncology.dk; Vestergaard-Poulsen, Peter; Nielsen, Thomas; Overgaard, Jens; Bjornerud, Atle; Briley-Saebo, Karen; Horsman, Michael R.; Ostergaard, Leif

    2005-03-15

    Purpose: To examine the feasibility of using the MRI blood pool agent NC100150 for evaluation of tumor blood volume (TBV) estimates by both dynamic contrast-enhanced MRI (DCE-MRI) and susceptibility contrast MRI assays in an experimental tumor. Contrast agent clearance (K{sup trans}; depends on perfusion and permeability) from the DCE-MRI time curves was estimated, and changes in TBV and K{sup trans} were measured after administration of two drugs that reduce perfusion by different mechanisms. Methods and materials: The DCE-MRI experiments were simulated with expected physiologic values for the C3H mouse mammary carcinoma. The C3H tumor was examined by DCE-MRI and susceptibility contrast MRI with NC100150 (NC100150 Injection, Clariscan; Amersham Health, Oslo, Norway) after treatment with either hydralazine or combretastatin (Oxigene, Boston, MA). Results: Simulations showed that reliable estimates of changes in TBV and K{sup trans} could be performed with DCE-MRI. Hydralazine was shown to reduce TBV as measured by both assays and to reduce K{sup trans}. Dynamic contrast-enhanced MRI also suggested that TBV and K{sup trans} were reduced in combretastatin-treated tumors, and the TBV reduction was confirmed by susceptibility contrast MRI. Data suggested the drug to affect mainly the total TBV, whereas microvessels as such seemed less altered. Conclusion: The study supports the use of the combined DCE-MRI and susceptibility contrast MRI assay with a blood pool agent in characterizing tumors and their response to treatment.

  2. Three-dimensional dynamic contrast-enhanced MRI for the accurate, extensive quantification of microvascular permeability in atherosclerotic plaques.

    PubMed

    Calcagno, Claudia; Lobatto, Mark E; Dyvorne, Hadrien; Robson, Philip M; Millon, Antoine; Senders, Max L; Lairez, Olivier; Ramachandran, Sarayu; Coolen, Bram F; Black, Alexandra; Mulder, Willem J M; Fayad, Zahi A

    2015-10-01

    Atherosclerotic plaques that cause stroke and myocardial infarction are characterized by increased microvascular permeability and inflammation. Dynamic contrast-enhanced MRI (DCE-MRI) has been proposed as a method to quantify vessel wall microvascular permeability in?vivo. Until now, most DCE-MRI studies of atherosclerosis have been limited to two-dimensional (2D) multi-slice imaging. Although providing the high spatial resolution required to image the arterial vessel wall, these approaches do not allow the quantification of plaque permeability with extensive anatomical coverage, an essential feature when imaging heterogeneous diseases, such as atherosclerosis. To our knowledge, we present the first systematic evaluation of three-dimensional (3D), high-resolution, DCE-MRI for the extensive quantification of plaque permeability along an entire vascular bed, with validation in atherosclerotic rabbits. We compare two acquisitions: 3D turbo field echo (TFE) with motion-sensitized-driven equilibrium (MSDE) preparation and 3D turbo spin echo (TSE). We find 3D TFE DCE-MRI to be superior to 3D TSE DCE-MRI in terms of temporal stability metrics. Both sequences show good intra- and inter-observer reliability, and significant correlation with ex?vivo permeability measurements by Evans Blue near-infrared fluorescence (NIRF). In addition, we explore the feasibility of using compressed sensing to accelerate 3D DCE-MRI of atherosclerosis, to improve its temporal resolution and therefore the accuracy of permeability quantification. Using retrospective under-sampling and reconstructions, we show that compressed sensing alone may allow the acceleration of 3D DCE-MRI by up to four-fold. We anticipate that the development of high-spatial-resolution 3D DCE-MRI with prospective compressed sensing acceleration may allow for the more accurate and extensive quantification of atherosclerotic plaque permeability along an entire vascular bed. We foresee that this approach may allow for the comprehensive and accurate evaluation of plaque permeability in patients, and may be a useful tool to assess the therapeutic response to approved and novel drugs for cardiovascular disease. PMID:26332103

  3. DCEMRI.jl: a fast, validated, open source toolkit for dynamic contrast enhanced MRI analysis

    PubMed Central

    Li, Xia; Arlinghaus, Lori R.; Yankeelov, Thomas E.; Welch, E. Brian

    2015-01-01

    We present a fast, validated, open-source toolkit for processing dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data. We validate it against the Quantitative Imaging Biomarkers Alliance (QIBA) Standard and Extended Tofts-Kety phantoms and find near perfect recovery in the absence of noise, with an estimated 10–20× speedup in run time compared to existing tools. To explain the observed trends in the fitting errors, we present an argument about the conditioning of the Jacobian in the limit of small and large parameter values. We also demonstrate its use on an in vivo data set to measure performance on a realistic application. For a 192 × 192 breast image, we achieved run times of <1 s. Finally, we analyze run times scaling with problem size and find that the run time per voxel scales as O(N1.9), where N is the number of time points in the tissue concentration curve. DCEMRI.jl was much faster than any other analysis package tested and produced comparable accuracy, even in the presence of noise. PMID:25922795

  4. 2013 Spring : Highly Distinguished Honors Highly Distinguished

    E-print Network

    Kunkle, Tom

    -riche Jeanmarc Robert Highly Distinguished Austin Adrian Thomas Highly Distinguished Awgulewitsch Cassandra_NAME MIDDLE_NAME HONORS Bartholomew Zak Henry Highly Distinguished Bassett Robert Jacob Highly Distinguished Highly Distinguished Boyd Jordan Dean Highly Distinguished Boyle Alyssa Anne Highly Distinguished Bradley

  5. Layer-Specific Manganese-Enhanced MRI of the Retina in Light and Dark Adaptation

    E-print Network

    Duong, Timothy Q.

    and imaged under anesthesia. T1-weighted MRI at 11.7 tesla (T) was performed using two identical radiofrequency transceiver coils to allow interleaved MRI acquisitions of the two eyes. An intravascular contrast was not statistically different between light and dark adaptation (P > 0.05). CONCLUSIONS. This study demonstrated

  6. Development and characterization of a dynamic lesion phantom for the quantitative evaluation of dynamic contrast-enhanced MRI

    PubMed Central

    Freed, Melanie; de Zwart, Jacco A.; Hariharan, Prasanna; R. Myers, Matthew; Badano, Aldo

    2011-01-01

    Purpose: To develop a dynamic lesion phantom that is capable of producing physiological kinetic curves representative of those seen in human dynamic contrast-enhanced MRI (DCE-MRI) data. The objective of this phantom is to provide a platform for the quantitative comparison of DCE-MRI protocols to aid in the standardization and optimization of breast DCE-MRI. Methods: The dynamic lesion consists of a hollow, plastic mold with inlet and outlet tubes to allow flow of a contrast agent solution through the lesion over time. Border shape of the lesion can be controlled using the lesion mold production method. The configuration of the inlet and outlet tubes was determined using fluid transfer simulations. The total fluid flow rate was determined using x-ray images of the lesion for four different flow rates (0.25, 0.5, 1.0, and 1.5 ml?s) to evaluate the resultant kinetic curve shape and homogeneity of the contrast agent distribution in the dynamic lesion. High spatial and temporal resolution x-ray measurements were used to estimate the true kinetic curve behavior in the dynamic lesion for benign and malignant example curves. DCE-MRI example data were acquired of the dynamic phantom using a clinical protocol. Results: The optimal inlet and outlet tube configuration for the lesion molds was two inlet molds separated by 30° and a single outlet tube directly between the two inlet tubes. X-ray measurements indicated that 1.0 ml?s was an appropriate total fluid flow rate and provided truth for comparison with MRI data of kinetic curves representative of benign and malignant lesions. DCE-MRI data demonstrated the ability of the phantom to produce realistic kinetic curves. Conclusions: The authors have constructed a dynamic lesion phantom, demonstrated its ability to produce physiological kinetic curves, and provided estimations of its true kinetic curve behavior. This lesion phantom provides a tool for the quantitative evaluation of DCE-MRI protocols, which may lead to improved discrimination of breast cancer lesions. PMID:21992378

  7. Assessment of ablative margin by MRI with ferucarbotran in radiofrequency ablation for liver cancer: comparison with enhanced CT

    PubMed Central

    Tokunaga, S; Koda, M; Matono, T; Sugihara, T; Nagahara, T; Ueki, M; Murawaki, Y; Kakite, S; Yamashita, E

    2012-01-01

    Objectives Our aim was to determine whether ablated liver parenchyma surrounding a tumour can be assessed by MRI with ferucarbotran administered prior to radiofrequency ablation (RFA) compared with enhanced CT. Methods 55 hepatocellular carcinomas (HCCs) in 42 patients and 5 metastatic liver cancers in 3 patients were treated by RFA after ferucarbotran administration. We then performed T2* weighted MRI after 1 week and enhanced CT after 1 month. T2* weighted MRI demonstrated the ablated parenchyma as a low-intensity rim around the high intensity of the ablated tumour in these cases. The assessment was allocated to one of three grades: margin (+), high-intensity area with continuous low-intensity rim; margin zero, high-intensity area with discontinuous low-intensity rim; and margin (?), high-intensity area extending beyond the low-intensity rim. Results Margin (+), margin zero and margin (?) were found in 17, 35 and 5 nodules, respectively. All 17 nodules with margin (+) and 13 of those with margin zero were assessed as having sufficient abalative margins on CT. The remaining 22 nodules with margin zero had insufficient margins on CT. The overall agreement between MRI and CT for the diagnosis of the ablative margin was moderate (?=0.507, p<0.001). No local recurrence was found in 15 HCC nodules with margin (+), whereas local recurrence was found in 4 (11.8%) out of 34 HCC nodules with margin zero. Conclusion Administration of ferucarbotran before RFA enables the ablative margin to be visualised as a low-intensity rim, and also enables the evaluation of the ablative margin to be made earlier and more easily than with enhanced CT. PMID:21385915

  8. Manganese-enhanced MRI detection of impaired calcium regulation in a mouse model of cardiac hypertrophy.

    PubMed

    Andrews, Martin; Giger, Maryellen L; Roman, Brian B

    2015-02-01

    The aim of this study was to use manganese (Mn)-enhanced MRI (MEMRI) to detect changes in calcium handling associated with cardiac hypertrophy in a mouse model, and to determine whether the impact of creatine kinase ablation is detectable using this method. Male C57BL/6 (C57, n?=?11) and male creatine kinase double-knockout (CK-M/Mito(-/-) , DBKO, n?=?12) mice were imaged using the saturation recovery Look-Locker T1 mapping sequence before and after the development of cardiac hypertrophy. Hypertrophy was induced via subcutaneous continuous 3-day infusion of isoproterenol, and sham mice not subjected to cardiac hypertrophy were also imaged. During each scan, the contrast agent Mn was administered and the resulting change in R1 (=1/T1) was calculated. Two anatomical regions of interest (ROIs) were considered, the left-ventricular free wall (LVFW) and the septum, and one ROI in an Mn-containing standard placed next to the mouse. We found statistically significant (p?

  9. Estimating kinetic parameter maps from dynamic contrast-enhanced MRI using spatial prior knowledge.

    PubMed

    Kelm, Bernd Michael; Menze, Bjoern H; Nix, Oliver; Zechmann, Christian M; Hamprecht, Fred A

    2009-10-01

    Dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging can be used to study microvascular structure in vivo by monitoring the abundance of an injected diffusible contrast agent over time. The resulting spatially resolved intensity-time curves are usually interpreted in terms of kinetic parameters obtained by fitting a pharmacokinetic model to the observed data. Least squares estimates of the highly nonlinear model parameters, however, can exhibit high variance and can be severely biased. As a remedy, we bring to bear spatial prior knowledge by means of a generalized Gaussian Markov random field (GGMRF). By using information from neighboring voxels and computing the maximum a posteriori solution for entire parameter maps at once, both bias and variance of the parameter estimates can be reduced thus leading to smaller root mean square error (RMSE). Since the number of variables gets very big for common image resolutions, sparse solvers have to be employed. To this end, we propose a generalized iterated conditional modes (ICM) algorithm operating on blocks instead of sites which is shown to converge considerably faster than the conventional ICM algorithm. Results on simulated DCE-MR images show a clear reduction of RMSE and variance as well as, in some cases, reduced estimation bias. The mean residual bias (MRB) is reduced on the simulated data as well as for all 37 patients of a prostate DCE-MRI dataset. Using the proposed algorithm, average computation times only increase by a factor of 1.18 (871 ms per voxel) for a Gaussian prior and 1.51 (1.12 s per voxel) for an edge-preserving prior compared to the single voxel approach (740 ms per voxel). PMID:19369150

  10. Delayed gadolinium-enhanced MRI of the fibrocartilage disc of the temporomandibular joint – a feasibility study

    PubMed Central

    Pittschieler, Elisabeth; Szomolanyi, Pavol; Schmid-Schwap, Martina; Weber, Michael; Egerbacher, Monika; Traxler, Hannes; Trattnig, Siegfried

    2014-01-01

    Objective To 1) test the feasibility of delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) at 3 T in the temporomandibular joint (TMJ) and 2) to determine the optimal delay for measurements of the TMJ disc after i.v. contrast agent (CA) administration. Design MRI of the right and left TMJ of six asymptomatic volunteers was performed at 3 T using a dedicated coil. 2D inversion recovery (2D-IR) sequences were performed at 4 time points covering 120 minutes and 3D gradient-echo (3D GRE) dual flip-angle sequences were performed at 14 time points covering 130 minutes after the administration of 0.2 mmol/kg of Gd-diethylenetriamine pentaacetic acid ion (Gd-DTPA)2-, i.e., 0.4 mL of Magnevist™ per kg body weight. Pair-wise tests were used to assess differences between pre-and post-contrast T1 values. Results 2D-IR sequences showed a statistically significant drop (p < 0.001) in T1 values after i.v. CA administration. The T1 drop of 50% was reached 60 minutes after bolus injection in the TMJ disc. The 3D GRE dual flip-angle sequences confirmed these results and show plateau of T1 after 60 minutes. Conclusions T1(Gd) maps calculated from dGEMRIC data allow in vivo assessment of the fibrocartilage disc of the TMJ. The recommended measurement time for dGEMRIC in the TMJ after i.v. CA administration is from 60 to 120 minutes. PMID:25131629

  11. Myocardial delayed enhancement in patients with pulmonary hypertension and right ventricular failure: evaluation by cardiac MRI.

    PubMed

    Junqueira, F P; Macedo, R; Coutinho, A C; Loureiro, R; De Pontes, P V; Domingues, R C; Gasparetto, E L

    2009-10-01

    In this study, we evaluated patients with pulmonary arterial hypertension (PAH) and impaired right ventricular function. We used cardiac MRI for the detection of myocardial delayed enhancement (MDE) and its possible association with other clinical variables. 20 patients (6 males and 14 females, aged 44.5+/-11 years; 15 New York Heart Association class III, 5 class IV) with known PAH (13 idiopathic, 7 resulting from chronic pulmonary embolism) were evaluated for the detection of MDE. Short-axis cine images of the heart were made for ventricular function assessment using a steady-state free precession sequence. For MDE evaluation, a short-axis phase-sensitive inversion recovery sequence was performed 10 min after intravenous administration of 0.2 mmol kg(-1) gadodiamide. Right ventricle (RV) systolic dysfunction, RV enlargement and RV hypertrophy were present in 20 patients (RV ejection fraction, 21.5+/-7.2%; RV diastolic diameter, 5.97+/-0.79 cm; RV wall thickness, 0.73+/-0.10 cm). 13 of the 20 patients (65%) were positive for MDE (10 anterior, 12 inferior). All 13 positive patients with MDE demonstrated small hyperintense areas at the insertion points of the RV free wall in the interventricular septum. We found no significant correlation between MDE and ejection fraction or other haemodynamic variables. In this study, MDE correlated positively only with the duration of disease. We found that septal MDE can be present in patients with PAH and impaired ventricular function. However, further studies are necessary to investigate this possible association and its prognostic implication. PMID:19398466

  12. Parameters of Dynamic Contrast-Enhanced MRI as Imaging Markers for Angiogenesis and Proliferation in Human Breast Cancer

    PubMed Central

    Li, Lin; Wang, Kai; Sun, Xilin; Wang, Kezheng; Sun, Yingying; Zhang, Guangfeng; Shen, Baozhong

    2015-01-01

    Background Breast cancer is the most common malignancy and the leading cause of cancer death in women worldwide; however, early diagnosis has been difficult due to its complex pathological structure. This study evaluated the value of morphological examination in conjunction with dynamic contrast-enhanced MRI (DCE-MRI) for more precise diagnosis of breast cancer, as well as their correlation with angiogenesis and proliferation biomarkers. Material/Methods DCE-MRI parameters (including Ktrans: volume transfer coefficient reflecting vascular permeability, Kep: flux rate constant, Ve: extracellular volume ratio reflecting vascular permeability, and ADC: apparent diffusion coefficient) were obtained from 124 patients with breast cancer (124 lesions). Microvessel density (MVD) was evaluated by the immunohistochemical analysis of tumor vessels for CD31 and CD105 expression. The proliferation was assessed by analyzing Ki67. Results Ktrans values were in the order of: malignant lesions > benign lesions > normal glands. Similar results were observed for Kep. The opposite changes were seen with Ve. Ktrans and Kep values were significantly higher in invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) than in mammary ductal dysplasia (MDD; ANOVA followed by Dunnett’s test). In sharp contrast, ADC values were lower in IDC and DCIS than in MDD, and Ve was not significantly different among the three groups. The data from MIP (maximum intensity projection) showed that benign breast lesions had no or only one blood vessel, whereas malignant lesions had two or more blood vessels. In addition, expression of CD105 and Ki67, the commonly recognized markers for angiogenesis and proliferation, respectively, were closely correlated with MRI parameters as revealed by Pearson analysis. Conclusions Determination of Ktrans, Kep and ADC values permits estimation of tumor angiogenesis and proliferation in breast cancer and DCE-MRI parameters can be used as imaging biomarkers to predict patient prognosis and the biologic aggressiveness of the tumor. PMID:25640082

  13. Magnetic Resonance Imaging (MRI)

    Cancer.gov

    Different tissues (including tumors) emit a more or less intense signal based on their chemical makeup, so a picture of the body organs can be displayed on a computer screen. Much like CT scans, MRI can produce three-dimensional images of sections of the body, but MRI is sometimes more sensitive than CT scans for distinguishing soft tissues.

  14. Enhanced control of dorsolateral prefrontal cortex neurophysiology with real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback training and working memory practice.

    PubMed

    Sherwood, Matthew S; Kane, Jessica H; Weisend, Michael P; Parker, Jason G

    2016-01-01

    Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback can be used to train localized, conscious regulation of blood oxygen level-dependent (BOLD) signals. As a therapeutic technique, rt-fMRI neurofeedback reduces the symptoms of a variety of neurologic disorders. To date, few studies have investigated the use of self-regulation training using rt-fMRI neurofeedback to enhance cognitive performance. This work investigates the utility of rt-fMRI neurofeedback as a tool to enhance human cognition by training healthy individuals to consciously control activity in the left dorsolateral prefrontal cortex (DLPFC). A cohort of 18 healthy participants in the experimental group underwent rt-fMRI neurofeedback from the left DLPFC in five training sessions across two weeks while 7 participants in the control group underwent similar training outside the MRI and without rt-fMRI neurofeedback. Working memory (WM) performance was evaluated on two testing days separated by the five rt-fMRI neurofeedback sessions using two computerized tests. We investigated the ability to control the BOLD signal across training sessions and WM performance across the two testing days. The group with rt-fMRI neurofeedback demonstrated a significant increase in the ability to self-regulate the BOLD signal in the left DLPFC across sessions. WM performance showed differential improvement between testing days one and two across the groups with the highest increases observed in the rt-fMRI neurofeedback group. These results provide evidence that individuals can quickly gain the ability to consciously control the left DLPFC, and this training results in improvements of WM performance beyond that of training alone. PMID:26348555

  15. Preliminary Study of Oxygen-Enhanced Longitudinal Relaxation in MRI: A Potential Novel Biomarker of Oxygenation Changes in Solid Tumors

    SciTech Connect

    O'Connor, James P.B.; Naish, Josephine H.; Parker, Geoff J.M.; Waterton, John C.; Watson, Yvonne; Jayson, Gordon C.; Buonaccorsi, Giovanni A.; Cheung, Sue; Buckley, David L.; McGrath, Deirdre M.; West, Catharine M.L.; Davidson, Susan E.; Roberts, Caleb; Mills, Samantha J.; Mitchell, Claire L.; Hope, Lynn; Ton, N. Chan; Jackson, Alan

    2009-11-15

    Purpose: There is considerable interest in developing non-invasive methods of mapping tumor hypoxia. Changes in tissue oxygen concentration produce proportional changes in the magnetic resonance imaging (MRI) longitudinal relaxation rate (R{sub 1}). This technique has been used previously to evaluate oxygen delivery to healthy tissues and is distinct from blood oxygenation level-dependent (BOLD) imaging. Here we report application of this method to detect alteration in tumor oxygenation status. Methods and materials: Ten patients with advanced cancer of the abdomen and pelvis underwent serial measurement of tumor R{sub 1} while breathing medical air (21% oxygen) followed by 100% oxygen (oxygen-enhanced MRI). Gadolinium-based dynamic contrast-enhanced MRI was then performed to compare the spatial distribution of perfusion with that of oxygen-induced DELTAR{sub 1}. Results: DELTAR{sub 1} showed significant increases of 0.021 to 0.058 s{sup -1} in eight patients with either locally recurrent tumor from cervical and hepatocellular carcinomas or metastases from ovarian and colorectal carcinomas. In general, there was congruency between perfusion and oxygen concentration. However, regional mismatch was observed in some tumor cores. Here, moderate gadolinium uptake (consistent with moderate perfusion) was associated with low area under the DELTAR{sub 1} curve (consistent with minimal increase in oxygen concentration). Conclusions: These results provide evidence that oxygen-enhanced longitudinal relaxation can monitor changes in tumor oxygen concentration. The technique shows promise in identifying hypoxic regions within tumors and may enable spatial mapping of change in tumor oxygen concentration.

  16. DistinguisheD teacher-scholar

    E-print Network

    Limpasuvan, Varavut

    2010 DistinguisheD teacher-scholar lecturer series coastal carolina university #12;coastal carolina university DistinguisheD teacher-scholar lecturer series presents Varavut Limpasuvan, Ph.D. ProfessorD teacher-scholar lecturer series The intent of the DistinguishedTeacher Scholar Lecturer Series

  17. A dimensionless dynamic contrast enhanced MRI parameter for intra-prostatic tumour target volume delineation: initial comparison with histology

    NASA Astrophysics Data System (ADS)

    Hrinivich, W. Thomas; Gibson, Eli; Gaed, Mena; Gomez, Jose A.; Moussa, Madeleine; McKenzie, Charles A.; Bauman, Glenn S.; Ward, Aaron D.; Fenster, Aaron; Wong, Eugene

    2014-03-01

    Purpose: T2 weighted and diffusion weighted magnetic resonance imaging (MRI) show promise in isolating prostate tumours. Dynamic contrast enhanced (DCE)-MRI has also been employed as a component in multi-parametric tumour detection schemes. Model-based parameters such as Ktrans are conventionally used to characterize DCE images and require arterial contrast agent (CR) concentration. A robust parameter map that does not depend on arterial input may be more useful for target volume delineation. We present a dimensionless parameter (Wio) that characterizes CR wash-in and washout rates without requiring arterial CR concentration. Wio is compared to Ktrans in terms of ability to discriminate cancer in the prostate, as demonstrated via comparison with histology. Methods: Three subjects underwent DCE-MRI using gadolinium contrast and 7 s imaging temporal resolution. A pathologist identified cancer on whole-mount histology specimens, and slides were deformably registered to MR images. The ability of Wio maps to discriminate cancer was determined through receiver operating characteristic curve (ROC) analysis. Results: There is a trend that Wio shows greater area under the ROC curve (AUC) than Ktrans with median AUC values of 0.74 and 0.69 respectively, but the difference was not statistically significant based on a Wilcoxon signed-rank test (p = 0.13). Conclusions: Preliminary results indicate that Wio shows potential as a tool for Ktrans QA, showing similar ability to discriminate cancer in the prostate as Ktrans without requiring arterial CR concentration.

  18. Quantification of Massive Allograft Healing with Dynamic Contrast Enhanced-MRI and Cone Beam-CT: A Pilot Study

    PubMed Central

    Ehrhart, Nicole; Kraft, Susan; Conover, David; Rosier, Randy N.

    2008-01-01

    Although massive allografts are widely used for reconstruction of critical defects in long bones caused by tumor or trauma, many will have inadequate long-term outcomes. Toward a tissue engineering solution to this problem, we developed experimental stem cell and gene therapy adjuvants that induce angiogenesis, osteogenesis, and remodeling of the structural allografts. We present data from pilot studies to show the utility of dynamic contrast enhanced MRI (DCE-MRI) to quantify vascularity after femoral osteotomy in a canine femur model and cone beam CT (CB-CT) to quantify bone volume in a patient after composite prosthetic-allograft reconstructive surgery. The results demonstrate our ability to suppress the artifacts generated by the metal implants required to secure massive allografts such that precise quantification of cortical bone revascularization (>10-fold increase at 3 weeks postoperatively) and new bone formation (accurate to about 193 ?m3) around the graft can be performed longitudinally via DCE-MRI and CB-CT, respectively. PMID:18543052

  19. Quantitative Estimation of Renal Function with Dynamic Contrast-Enhanced MRI Using a Modified Two-Compartment Model

    PubMed Central

    Chen, Bin; Zhang, Yudong; Song, Xiaojian; Wang, Xiaoying; Zhang, Jue; Fang, Jing

    2014-01-01

    Objective To establish a simple two-compartment model for glomerular filtration rate (GFR) and renal plasma flow (RPF) estimations by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Materials and Methods A total of eight New Zealand white rabbits were included in DCE-MRI. The two-compartment model was modified with the impulse residue function in this study. First, the reliability of GFR measurement of the proposed model was compared with other published models in Monte Carlo simulation at different noise levels. Then, functional parameters were estimated in six healthy rabbits to test the feasibility of the new model. Moreover, in order to investigate its validity of GFR estimation, two rabbits underwent acute ischemia surgical procedure in unilateral kidney before DCE-MRI, and pixel-wise measurements were implemented to detect the cortical GFR alterations between normal and abnormal kidneys. Results The lowest variability of GFR and RPF measurements were found in the proposed model in the comparison. Mean GFR was 3.03±1.1 ml/min and mean RPF was 2.64±0.5 ml/g/min in normal animals, which were in good agreement with the published values. Moreover, large GFR decline was found in dysfunction kidneys comparing to the contralateral control group. Conclusion Results in our study demonstrate that measurement of renal kinetic parameters based on the proposed model is feasible and it has the ability to discriminate GFR changes in healthy and diseased kidneys. PMID:25141138

  20. fMRI neurofeedback of amygdala response to aversive stimuli enhances prefrontal-limbic brain connectivity.

    PubMed

    Paret, Christian; Ruf, Matthias; Gerchen, Martin Fungisai; Kluetsch, Rosemarie; Demirakca, Traute; Jungkunz, Martin; Bertsch, Katja; Schmahl, Christian; Ende, Gabriele

    2016-01-15

    Down-regulation of the amygdala with real-time fMRI neurofeedback (rtfMRI NF) potentially allows targeting brain circuits of emotion processing and may involve prefrontal-limbic networks underlying effective emotion regulation. Little research has been dedicated to the effect of rtfMRI NF on the functional connectivity of the amygdala and connectivity patterns in amygdala down-regulation with neurofeedback have not been addressed yet. Using psychophysiological interaction analysis of fMRI data, we present evidence that voluntary amygdala down-regulation by rtfMRI NF while viewing aversive pictures was associated with increased connectivity of the right amygdala with the ventromedial prefrontal cortex (vmPFC) in healthy subjects (N=16). In contrast, a control group (N=16) receiving sham feedback did not alter amygdala connectivity (Group×Condition t-contrast: p<.05 at cluster-level). Task-dependent increases in amygdala-vmPFC connectivity were predicted by picture arousal (?=.59, p<.05). A dynamic causal modeling analysis with Bayesian model selection aimed at further characterizing the underlying causal structure and favored a bottom-up model assuming predominant information flow from the amygdala to the vmPFC (xp=.90). The results were complemented by the observation of task-dependent alterations in functional connectivity of the vmPFC with the visual cortex and the ventrolateral PFC in the experimental group (Condition t-contrast: p<.05 at cluster-level). Taken together, the results underscore the potential of amygdala fMRI neurofeedback to influence functional connectivity in key networks of emotion processing and regulation. This may be beneficial for patients suffering from severe emotion dysregulation by improving neural self-regulation. PMID:26481674

  1. Gd-DTPA-enhanced magnetic resonance imaging (MRI) for the follow-up of laser-induced thermotherapy (LITT): trial to determine a useful examination schedule

    NASA Astrophysics Data System (ADS)

    Germer, Christoph-Thomas; Isbert, Christoph M.; Albrecht, Dirk; Ritz, Joerg-Peter; Schilling, Andreas; Roggan, Andre; Wolf, Karl J.; Mueller, Gerhard J.; Buhr, Heinz-Johannes

    1998-01-01

    Purpose: To evaluate gadolinium-DTPA-enhanced MRI for follow-up monitoring of laser-induced thermotherapy (LITT) and to determine of a useful examination schedule. Materials and Methods: LITT Of the liver was performed in 55 rabbits using a Nd:YAG laser (4 w power output, 840 s exposure time). Gd-DTPA MRI and histological examinations were performed at different times (0 - 168 days). Results: Laser- induced lesions underwent regeneration and volume size reduction (69% after 168 days). The correlation coefficient (MR vs macroscopic analysis) for the mean lesion diameter was r equals 0.96. Histology of lesions comprised the four zones that correlated best with MRI findings. Coagulation necroses immediately after LITT were seen as an area of no enhancement on Gd-DTPA MRI. Circular enhancement was first seen 72 - 96 hours after LITT, which was due to early mesenchymal proliferation. Conclusions: Gd-DTPA MRI is a good monitoring procedure for LITT. MRI should be performed 24 and 96 hours after LITT.

  2. Multimodal visualization of 3D enhanced MRI and CT of acoustic schwannoma and related structures

    NASA Astrophysics Data System (ADS)

    Kucharski, Tomasz; Kujawinska, Malgorzata; Niemczyk, Kazimierz; Marchel, Andrzej

    2005-09-01

    According to the necessity of supporting vestibular schwannoma surgery, there is a demand to develop a convenient method of medical data visualization. The process of making choice of optimal operating access way has been uncomfortable for a surgeon so far, because there has been a necessity of analyzing two independent 3D images series (CT -bone tissues visible, MRI - soft tissues visible) in the region of ponto-cerebellar angle tumors. The authors propose a solution that will improve this process. The system used is equipped with stereoscopic helmet mounted display. It allows merged CT and MRI data representing tissues in the region of of ponto-cerebellar angle to be visualized in stereoscopic way. The process of data preparation for visualization includes: -automated segmentation algorithms, -different types of 3D images (CT, MRI) fusion. The authors focused on the development of novel algorithms for segmentation of vestibular schwannoma. It is important and difficult task due to different types of tumors and their inhomogeneous character dependent on growth models. The authors propose algorithms based on histogram spectrum and multimodal character of MRI imaging (T1 and T2 modes). However due to a variety of objects the library of algorithms with specific modifications matching to selected types of images is proposed. The applicability and functionality of the algorithms and library was proved on the series of data delivered by Warsaw Central Medical University Hospital.

  3. Enhancing 4D PC-MRI in an aortic phantom considering numerical simulations

    NASA Astrophysics Data System (ADS)

    Kratzke, Jonas; Schoch, Nicolai; Weis, Christian; Müller-Eschner, Matthias; Speidel, Stefanie; Farag, Mina; Beller, Carsten J.; Heuveline, Vincent

    2015-03-01

    To date, cardiovascular surgery enables the treatment of a wide range of aortic pathologies. One of the current challenges in this field is given by the detection of high-risk patients for adverse aortic events, who should be treated electively. Reliable diagnostic parameters, which indicate the urge of treatment, have to be determined. Functional imaging by means of 4D phase contrast-magnetic resonance imaging (PC-MRI) enables the time-resolved measurement of blood flow velocity in 3D. Applied to aortic phantoms, three dimensional blood flow properties and their relation to adverse dynamics can be investigated in vitro. Emerging "in silico" methods of numerical simulation can supplement these measurements in computing additional information on crucial parameters. We propose a framework that complements 4D PC-MRI imaging by means of numerical simulation based on the Finite Element Method (FEM). The framework is developed on the basis of a prototypic aortic phantom and validated by 4D PC-MRI measurements of the phantom. Based on physical principles of biomechanics, the derived simulation depicts aortic blood flow properties and characteristics. The framework might help identifying factors that induce aortic pathologies such as aortic dilatation or aortic dissection. Alarming thresholds of parameters such as wall shear stress distribution can be evaluated. The combined techniques of 4D PC-MRI and numerical simulation can be used as complementary tools for risk-stratification of aortic pathology.

  4. Enhancing Motor Network Activity Using Real-Time Functional MRI Neurofeedback of Left Premotor Cortex.

    PubMed

    Marins, Theo F; Rodrigues, Erika C; Engel, Annerose; Hoefle, Sebastian; Basílio, Rodrigo; Lent, Roberto; Moll, Jorge; Tovar-Moll, Fernanda

    2015-01-01

    Neurofeedback by functional magnetic resonance imaging (fMRI) is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC), important for motor recovery after brain injury. We investigated (i) whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI) task while receiving continuous fMRI-neurofeedback, and (ii) whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB) received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL) group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and MI, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke. PMID:26733832

  5. Enhancing Motor Network Activity Using Real-Time Functional MRI Neurofeedback of Left Premotor Cortex

    PubMed Central

    Marins, Theo F.; Rodrigues, Erika C.; Engel, Annerose; Hoefle, Sebastian; Basílio, Rodrigo; Lent, Roberto; Moll, Jorge; Tovar-Moll, Fernanda

    2015-01-01

    Neurofeedback by functional magnetic resonance imaging (fMRI) is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC), important for motor recovery after brain injury. We investigated (i) whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI) task while receiving continuous fMRI-neurofeedback, and (ii) whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB) received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL) group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and MI, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke.

  6. Rationally Separating the Corona and Membrane Functions of Polymer Vesicles for Enhanced T? MRI and Drug Delivery.

    PubMed

    Qin, Jingya; Liu, Qiuming; Zhang, Junxue; Chen, Jing; Chen, Shuai; Zhao, Yao; Du, Jianzhong

    2015-07-01

    It is an important challenge to in situ grow ultrafine super-paramagnetic iron oxide nanoparticles (SPIONs) in drug carriers such as polymer vesicles (also called polymersomes) while keeping their biodegradability for enhanced T2-weighted magnetic resonance imaging (MRI) and drug delivery. Herein, we present a new strategy by rationally separating the corona and membrane functions of polymer vesicles to solve the above problem. We designed a poly(ethylene oxide)-block-poly(?-caprolactone)-block-poly(acrylic acid) (PEO43-b-PCL98-b-PAA25) triblock copolymer and self-assembled it into polymer vesicle. The PAA chains in the vesicle coronas are responsible for the in situ nanoprecipitation of ultrafine SPIONs, while the vesicle membrane composed of PCL is biodegradable. The SPIONs-decorated vesicle is water-dispersible, biocompatible, and slightly cytotoxic to normal human cells. Dynamic light scattering, transmission electron microscopy, energy disperse spectroscopy, and vibrating sample magnetometer revealed the formation of ultrafine super-paramagnetic Fe3O4 nanoparticles (1.9 ± 0.3 nm) in the coronas of polymer vesicles. Furthermore, the CCK-8 assay revealed low cytotoxicity of vesicles against normal L02 liver cells without and with Fe3O4 nanoparticles. The in vitro and in vivo MRI experiments confirmed the enhanced T2-weighted MRI sensitivity and excellent metastasis in mice. The loading and release experiments of an anticancer drug, doxorubicin hydrochloride (DOX·HCl), indicated that the Fe3O4-decorated magnetic vesicles have potential applications as a nanocarrier for anticancer drug delivery. Moreover, the polymer vesicle is degradable in the presence of enzyme such as Pseudomonas lipases, and the ultrafine Fe3O4 nanoparticles in the vesicle coronas are confirmed to be degradable under weakly acidic conditions. Overall, this decoration-in-vesicle-coronas strategy provides us with a new insight for preparing water-dispersible ultrafine super-paramagnetic Fe3O4 nanoparticles with promising theranostic applications in biomedicine. PMID:26046951

  7. SPIO-conjugated, doxorubicin-loaded microbubbles for concurrent MRI and focused-ultrasound enhanced brain-tumor drug delivery.

    PubMed

    Fan, Ching-Hsiang; Ting, Chien-Yu; Lin, Han-Jung; Wang, Chung-Hsin; Liu, Hao-Li; Yen, Tzu-Chen; Yeh, Chih-Kuang

    2013-05-01

    The blood-brain barrier (BBB) can be temporarily and locally opened by focused ultrasound (FUS) in the presence of circulating microbubbles (MBs). Currently, contrast-enhanced magnetic resonance imaging (CE-MRI) is used to monitor contrast agent leakage to verify BBB-opening and infer drug deposition. However, despite being administered concurrently, MBs, therapeutic agent, and contrast agent have distinct pharmacodynamic behaviors, thus complicating the quantification and optimization of BBB-opening and drug delivery. Here we propose multifunctional MBs loaded with therapeutic agent (doxorubicin; DOX) and conjugated with superparamagnetic iron oxide (SPIO) nanoparticles. These DOX-SPIO-MBs were designed to concurrently open the BBB and perform drug delivery upon FUS exposure, act as dual MRI and ultrasound contrast agent, and allow magnetic targeting (MT) to achieve enhanced drug delivery. We performed burst-tone FUS after injection of DOX-SPIO-MBs, followed by MT with an external magnet attached to the scalp in a rat glioma model. Animals were monitored by T2-weighted MRI and susceptibility weighted imaging and the concentration of SPIO particles was determined by spin-spin relaxivity. We found that DOX-SPIO-MBs were stable and provided significant superparamagnetic/acoustic properties for imaging. BBB-opening and drug delivery were achieved concurrently during the FUS exposure. In addition, MT increased local SPIO deposition in tumor regions by 22.4%. Our findings suggest that DOX-SPIO-MBs with FUS could be an excellent theranostic tool for future image-guided drug delivery to brain tumors. PMID:23433776

  8. A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience

    PubMed Central

    Cheng, Cheng; Kuang, Lian-qin; Zhang, Yu-long; Cheng, Hai-yun; Min, Jia-yan; Wang, Yi

    2015-01-01

    Purpose. Manganese-enhanced MRI (MEMRI) has been applied to a wide range of biological and disease research. The purpose of the study was to use MEMRI to diagnose the acute mesenteric ischemia (AMI). Methods. The institutional experimental animal ethics committee approved this study. To optimize the dose of Mn2+ infusion, a dose-dependent curve was obtained using Mn2+-enhanced T1 map MRI by an intravenous infusion 2.5–20?nmol/g body weight (BW) of 50?nmol/L MnCl2. The eighteen animals were divided into control, sham-operated, and AMI groups. AMI models were performed by ligating the superior mesenteric artery (SMA). T1 values were measured on T1 maps in regions of the small intestinal wall and relaxation rate (?R1) was calculated. Results. A nonlinear relationship between infused MnCl2 solution dose and increase in small intestinal wall ?R1 was observed. Control animal exhibited significant Mn2+ clearance over time at the dose of 15?nmol/g BW. In the AMI model, ?R1 values (0.95 ± 0.13) in the small intestinal wall were significantly lower than in control group (2.05 ± 0.19) after Mn2+ infusion (P < 0.01). Conclusion. The data suggest that MEMRI shows potential as a diagnostic technique that is directly sensitive to the poor or absent perfusion in AMI. PMID:26693487

  9. Head MRI

    MedlinePLUS

    ... the head; MRI - cranial; NMR - cranial; Cranial MRI; Brain MRI; MRI - brain; MRI - head ... tell your health care provider if you have: Brain aneurysm clips Certain types of artificial heart valves ...

  10. The use of error-category mapping in pharmacokinetic model analysis of dynamic contrast-enhanced MRI data.

    PubMed

    Gill, Andrew B; Anandappa, Gayathri; Patterson, Andrew J; Priest, Andrew N; Graves, Martin J; Janowitz, Tobias; Jodrell, Duncan I; Eisen, Tim; Lomas, David J

    2015-02-01

    This study introduces the use of 'error-category mapping' in the interpretation of pharmacokinetic (PK) model parameter results derived from dynamic contrast-enhanced (DCE-) MRI data. Eleven patients with metastatic renal cell carcinoma were enrolled in a multiparametric study of the treatment effects of bevacizumab. For the purposes of the present analysis, DCE-MRI data from two identical pre-treatment examinations were analysed by application of the extended Tofts model (eTM), using in turn a model arterial input function (AIF), an individually-measured AIF and a sample-average AIF. PK model parameter maps were calculated. Errors in the signal-to-gadolinium concentration ([Gd]) conversion process and the model-fitting process itself were assigned to category codes on a voxel-by-voxel basis, thereby forming a colour-coded 'error-category map' for each imaged slice. These maps were found to be repeatable between patient visits and showed that the eTM converged adequately in the majority of voxels in all the tumours studied. However, the maps also clearly indicated sub-regions of low Gd uptake and of non-convergence of the model in nearly all tumours. The non-physical condition ve ? 1 was the most frequently indicated error category and appeared sensitive to the form of AIF used. This simple method for visualisation of errors in DCE-MRI could be used as a routine quality-control technique and also has the potential to reveal otherwise hidden patterns of failure in PK model applications. PMID:25460333

  11. In-Vivo Imaging of Cell Migration Using Contrast Enhanced MRI and SVM Based Post-Processing

    PubMed Central

    Budinsky, Lubos; Fabry, Ben

    2015-01-01

    The migration of cells within a living organism can be observed with magnetic resonance imaging (MRI) in combination with iron oxide nanoparticles as an intracellular contrast agent. This method, however, suffers from low sensitivity and specificty. Here, we developed a quantitative non-invasive in-vivo cell localization method using contrast enhanced multiparametric MRI and support vector machines (SVM) based post-processing. Imaging phantoms consisting of agarose with compartments containing different concentrations of cancer cells labeled with iron oxide nanoparticles were used to train and evaluate the SVM for cell localization. From the magnitude and phase data acquired with a series of T2*-weighted gradient-echo scans at different echo-times, we extracted features that are characteristic for the presence of superparamagnetic nanoparticles, in particular hyper- and hypointensities, relaxation rates, short-range phase perturbations, and perturbation dynamics. High detection quality was achieved by SVM analysis of the multiparametric feature-space. The in-vivo applicability was validated in animal studies. The SVM detected the presence of iron oxide nanoparticles in the imaging phantoms with high specificity and sensitivity with a detection limit of 30 labeled cells per mm3, corresponding to 19 ?M of iron oxide. As proof-of-concept, we applied the method to follow the migration of labeled cancer cells injected in rats. The combination of iron oxide labeled cells, multiparametric MRI and a SVM based post processing provides high spatial resolution, specificity, and sensitivity, and is therefore suitable for non-invasive in-vivo cell detection and cell migration studies over prolonged time periods. PMID:26656497

  12. Gd-EOB-DTPA-enhanced 3.0-Tesla MRI findings for the preoperative detection of focal liver lesions: Comparison with iodine-enhanced multi-detector computed tomography

    NASA Astrophysics Data System (ADS)

    Park, Hyong-Hu; Goo, Eun-Hoe; Im, In-Chul; Lee, Jae-Seung; Kim, Moon-Jib; Kwak, Byung-Joon; Chung, Woon-Kwan; Dong, Kyung-Rae

    2012-12-01

    The safety of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid (Gd-EOB-DTPA) has been confirmed, but more study is needed to assess the diagnostic accuracy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in patients with a hepatocellular carcinoma (HCC) for whom surgical treatment is considered or with a metastatic hepatoma. Research is also needed to examine the rate of detection of hepatic lesions compared to multi-detector computed tomography (MDCT), which is used most frequently to localize and characterize a HCC. Gd-EOB-DTPA-enhanced MRI and iodine-enhanced MDCT imaging were compared for the preoperative detection of focal liver lesions. The clinical usefulness of each method was examined. The current study enrolled 79 patients with focal liver lesions who preoperatively underwent MRI and MDCT. In these patients, there was less than one month between the two diagnostic modalities. Imaging data were taken before and after contrast enhancement in both methods. To evaluate the images, we analyzed the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) in the lesions and the liver parenchyma. To compare the sensitivity of the two methods, we performed a quantitative analysis of the percentage signal intensity of the liver (PSIL) on a high resolution picture archiving and communication system (PACS) monitor (paired-samples t-test, p < 0.05). The enhancement was evaluated based on a consensus of four observers. The enhancement pattern and the morphological features during the arterial and the delayed phases were correlated between the Gd-EOB-DTPA-enhanced MRI findings and the iodine-enhanced MDCT by using an adjusted x2 test. The SNRs, CNRs, and PSIL all had a greater detection rate in Gd-EOB-DTPA enhanced MRI than in iodine-enhanced MDCT. Hepatocyte-selective uptake was observed 20 minutes after the injection in the focal nodular hyperplasia (FNH, 9/9), adenoma (9/10), and highly-differentiated HCC (grade G1, 27/30). Rim enhancement was detected in all metastases (30/30). During the arterial and the delayed phases, good overall agreement between the gadoxetic-acid-enhanced MR and CT was observed (x2 test, p < 0.05). For the preoperative detection of focal liver lesions, Gd-EOB-DTPA-enhanced MRI had a higher diagnostic value and higher detection rate than iodine-enhanced MDCT. The arterial and the delayed dynamic enhancement patterns, and the gadoxetic-acid-enhanced MR imaging can provide information on the possible degree of cellular differentiation of a HCC, adenoma or metastatic tumor.

  13. Functional Lung MRI in Chronic Obstructive Pulmonary Disease: Comparison of T1 Mapping, Oxygen-Enhanced T1 Mapping and Dynamic Contrast Enhanced Perfusion

    PubMed Central

    Jobst, Bertram J.; Triphan, Simon M. F.; Sedlaczek, Oliver; Anjorin, Angela; Kauczor, Hans Ulrich; Biederer, Jürgen; Ley-Zaporozhan, Julia; Ley, Sebastian; Wielpütz, Mark O.

    2015-01-01

    Purpose Monitoring of regional lung function in interventional COPD trials requires alternative endpoints beyond global parameters such as FEV1. T1 relaxation times of the lung might allow to draw conclusions on tissue composition, blood volume and oxygen fraction. The aim of this study was to evaluate the potential value of lung Magnetic resonance imaging (MRI) with native and oxygen-enhanced T1 mapping for the assessment of COPD patients in comparison with contrast enhanced perfusion MRI. Materials and Methods 20 COPD patients (GOLD I-IV) underwent a coronal 2-dimensional inversion recovery snapshot flash sequence (8 slices/lung) at room air and during inhalation of pure oxygen, as well as dynamic contrast-enhanced first-pass perfusion imaging. Regional distribution of T1 at room air (T1), oxygen-induced T1 shortening (?T1) and peak enhancement were rated by 2 chest radiologists in consensus using a semi-quantitative 3-point scale in a zone-based approach. Results Abnormal T1 and ?T1 were highly prevalent in the patient cohort. T1 and ?T1 correlated positively with perfusion abnormalities (r = 0.81 and r = 0.80; p&0.001), and with each other (r = 0.80; p<0.001). In GOLD stages I and II ?T1 was normal in 16/29 lung zones with mildly abnormal perfusion (15/16 with abnormal T1). The extent of T1 (r = 0.45; p<0.05), ?T1 (r = 0.52; p<0.05) and perfusion abnormalities (r = 0.52; p<0.05) showed a moderate correlation with GOLD stage. Conclusion Native and oxygen-enhanced T1 mapping correlated with lung perfusion deficits and severity of COPD. Under the assumption that T1 at room air correlates with the regional pulmonary blood pool and that oxygen-enhanced T1 reflects lung ventilation, both techniques in combination are principally suitable to characterize ventilation-perfusion imbalance. This appears valuable for the assessment of regional lung characteristics in COPD trials without administration of i.v. contrast. PMID:25822195

  14. Automated scoring of regional lung perfusion in children from contrast enhanced 3D MRI

    NASA Astrophysics Data System (ADS)

    Heimann, Tobias; Eichinger, Monika; Bauman, Grzegorz; Bischoff, Arved; Puderbach, Michael; Meinzer, Hans-Peter

    2012-03-01

    MRI perfusion images give information about regional lung function and can be used to detect pulmonary pathologies in cystic fibrosis (CF) children. However, manual assessment of the percentage of pathologic tissue in defined lung subvolumes features large inter- and intra-observer variation, making it difficult to determine disease progression consistently. We present an automated method to calculate a regional score for this purpose. First, lungs are located based on thresholding and morphological operations. Second, statistical shape models of left and right children's lungs are initialized at the determined locations and used to precisely segment morphological images. Segmentation results are transferred to perfusion maps and employed as masks to calculate perfusion statistics. An automated threshold to determine pathologic tissue is calculated and used to determine accurate regional scores. We evaluated the method on 10 MRI images and achieved an average surface distance of less than 1.5 mm compared to manual reference segmentations. Pathologic tissue was detected correctly in 9 cases. The approach seems suitable for detecting early signs of CF and monitoring response to therapy.

  15. Enhanced resting-state brain activities in ADHD patients: a fMRI study.

    PubMed

    Tian, Lixia; Jiang, Tianzi; Liang, Meng; Zang, Yufeng; He, Yong; Sui, Manqiu; Wang, Yufeng

    2008-05-01

    Resting-state functional MRI (fMRI) could be an advantageous choice for clinical applications by virtue of its clinical convenience and non-invasiveness. Without explicit stimulus, resting-state brain activity patterns cannot be obtained using any model-driven method. In this study, we advanced a measure named resting-state activity index (RSAI) to evaluate the resting-state brain activities. Using RSAI, we first investigated the resting-state brain activity patterns in normal adolescents to test the validity of this RSAI measure. Then we compared the resting-state brain activity patterns of Attention deficit hyperactivity disorder (ADHD) patients to those of their matched controls. According to the resultant brain activity patterns, we suggest that RSAI could be an applicable measure to evaluate resting-state brain activities. As compared to the controls, the ADHD patients exhibited more significant resting-state activities in basic sensory and sensory-related cortices. This finding was in accordance with ADHD symptoms of inattention. PMID:18060712

  16. Correction of Arterial Input Function in Dynamic Contrast-Enhanced MRI of the Liver

    PubMed Central

    Wang, Hesheng; Cao, Yue

    2012-01-01

    Purpose To develop a post-processing method to correct saturation of arterial input function (AIF) in T1-weighted DCE-MRI for quantification of hepatic perfusion. Materials and Methods The saturated AIF is corrected by parameterizing the first pass of the AIF as a smooth function with a single peak and minimizing a least squares error in fitting the liver DCE-MRI data to a dual-input single-compartment model. Sensitivities of the method to the degree of saturation in the AIF first-pass peak and the image contrast-to-noise ratio were assessed. The method was also evaluated by correlating portal venous perfusion with an independent overall liver function measurement. Results The proposed method corrects the distorted AIF with a saturation ratio up to 0.45. The corrected AIF improves hepatic arterial perfusion by ?23.4% and portal venous perfusion by 26.9% in a study of 12 patients with liver cancers. The correlation between the mean voxelwise portal venous perfusion and overall liver function measurement was improved by using the corrected AIFs (R2=0.67) compared with the saturated AIFs (R2=0.39). Conclusion The method is robust for correcting AIF distortion, and has the potential to improve quantification of hepatic perfusion for assessment of liver tissue response to treatment in patients with hepatic cancers. PMID:22392876

  17. Layer-Specific Manganese-Enhanced MRI of the Diabetic Rat Retina in Light and Dark Adaptation at 11.7 Tesla

    E-print Network

    Duong, Timothy Q.

    Adaptation at 11.7 Tesla Eric R. Muir,1,2 Saurav B. Chandra,1 Bryan H. De La Garza,1 Chakradhar Velagapudi,3- enhanced MRI of the diabetic rat retina in light and dark adaptation at 11.7 tesla. Invest Ophthalmol Vis

  18. Tumor perfusion assessed by dynamic contrast-enhanced MRI correlates to the grading of renal cell carcinoma: initial results.

    PubMed

    Palmowski, Moritz; Schifferdecker, Isabel; Zwick, Stefan; Macher-Goeppinger, Stephan; Laue, Hendrik; Haferkamp, Axel; Kauczor, Hans-Ulrich; Kiessling, Fabian; Hallscheidt, Peter

    2010-06-01

    In this study, we investigated whether assessment of the tumor perfusion by dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) enables to estimate the morphologic grading of renal cell carcinomas. A total of 21 patients with suspected renal cell cancer were examined using a Gadobutrol-enhanced, dynamic saturation-recovery, turbo-fast, low-angle shot sequence. Tumor perfusion and the tissue-blood ratio within the entire tumor and the most highly vascularized part of the tumor were calculated according to the model of Miles. Immediately after examination, patients underwent surgery, and the results from imaging were compared with the morphological analysis of the histologic grading. Fourteen patients had G2 tumors, and seven patients had G3 tumors. Significantly higher perfusion values (p<0.05) were obtained in G3 tumors than in G2 tumors when the entire tumor area was considered (1.59+/-0.44(ml/g/min) vs. 1.08+/-0.38(ml/g/min)) or its most highly vascularized part (2.14+/-0.89(ml/g/min) vs. 1.40+/-0.49(ml/g/min)). By contrast, the tissue-blood ratios did not differ significantly between the two groups. In conclusion, unlike tissue-blood ratio, surrogate parameters of the tumor perfusion determined by DCE MRI seem to allow an estimation of the grading of renal cell carcinoma. However, further studies with high case numbers and including patients with G1 tumors are required to evaluate the full potential and clinical impact. PMID:19540690

  19. Monitoring Pc 4-mediated photodynamic therapy of U87 tumors with dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) in the athymic nude rat

    NASA Astrophysics Data System (ADS)

    Varghai, Davood; Covey, Kelly; Sharma, Rahul; Cross, Nathan; Feyes, Denise K.; Oleinick, Nancy L.; Flask, Chris A.; Dean, David

    2008-02-01

    Post-operative verification of the specificity and sensitivity of photodynamic therapy (PDT) is most pressing for deeply placed lesions such as brain tumors. We wish to determine whether Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI) can provide a non-invasive and unambiguous quantitative measure of the specificity and sensitivity of brain tumor PDT. Methods: 2.5 x 10 5 U87 cells were injected into the brains of six athymic nude rats. After 5-6 days, the animals received 0.5 mg/kg b.w. of the phthalocyanine photosensitizer Pc 4 via tail-vein injection. On day 7 peri-tumor DCE-MRI images were acquired on a 7T microMRI scanner before and after tail-vein administration of 100 ?L gadolinium and 400 ?L saline. After this scan the animals received a 30 J/cm2 dose of 672-nm light from a diode laser (i.e., PDT). The DCE-MRI scan protocol was repeated on day 13. Next, the animals were euthanized and their brains were explanted for Hematoxylin and Eosin (H&E) histology. Results: No tumor was found in one animal. The DCE-MRI images of the other five animals demonstrated significant tumor enhancement increase (p < 0.053 two-sided t-test and p < 0.026 one-sided t-test) following PDT. H&E histology presented moderate to severe tumor necrosis. Discussion: The change in signal detected by DCE-MRI appears to be due to PDT-induced tumor necrosis. This DCE-MRI signal appears to provide a quantitative, non-invasive measure of the outcome of PDT in this animal model and may be useful for determining the safety and effectiveness of PDT in deeply placed tumors (e.g., glioma).

  20. Dynamic Contrast-Enhanced MRI Using a Macromolecular MR Contrast Agent (P792): Evaluation of Antivascular Drug Effect in a Rabbit VX2 Liver Tumor Model

    PubMed Central

    Park, Hee Sun; Lee, Jeong Min; Kim, Young Il; Woo, Sungmin; Yoon, Jung Hwan; Choi, Jin-Young; Choi, Byung Ihn

    2015-01-01

    Objective To evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using macromolecular contrast agent (P792) for assessment of vascular disrupting drug effect in rabbit VX2 liver tumor models. Materials and Methods This study was approved by our Institutional Animal Care and Use Committee. DCE-MRI was performed with 3-T scanner in 13 VX2 liver tumor-bearing rabbits, before, 4 hours after, and 24 hours after administration of vascular disrupting agent (VDA), using gadomelitol (P792, n = 7) or low molecular weight contrast agent (gadoterate meglumine [Gd-DOTA], n = 6). P792 was injected at a of dose 0.05 mmol/kg, while that of Gd-DOTA was 0.2 mmol/kg. DCE-MRI parameters including volume transfer coefficient (Ktrans) and initial area under the gadolinium concentration-time curve until 60 seconds (iAUC) of tumors were compared between the 2 groups at each time point. DCE-MRI parameters were correlated with tumor histopathology. Reproducibility in measurement of DCE-MRI parameters and image quality of source MR were compared between groups. Results P792 group showed a more prominent decrease in Ktrans and iAUC at 4 hours and 24 hours, as compared to the Gd-DOTA group. Changes in DCE-MRI parameters showed a weak correlation with histologic parameters (necrotic fraction and microvessel density) in both groups. Reproducibility of DCE-MRI parameters and overall image quality was not significantly better in the P792 group, as compared to the Gd-DOTA group. Conclusion Dynamic contrast-enhanced magnetic resonance imaging using a macromolecular contrast agent shows changes of hepatic perfusion more clearly after administration of the VDA. Gadolinium was required at smaller doses than a low molecular contrast agent. PMID:26357497

  1. Hepatocellular Adenoma: Evaluation with Contrast-Enhanced Ultrasound and MRI and Correlation with Pathologic and Phenotypic Classification in 26 Lesions

    PubMed Central

    Manichon, Anne-Frédérique; Bancel, Brigitte; Durieux-Millon, Marion; Ducerf, Christian; Mabrut, Jean-Yves; Lepogam, Marie-Annick; Rode, Agnès

    2012-01-01

    Purpose. To review the contrast-enhanced ultrasonographic (CEUS) and magnetic resonance (MR) imaging findings in 25 patients with 26 hepatocellular adenomas (HCAs) and to compare imaging features with histopathologic results from resected specimen considering the new immunophenotypical classification. Material and Methods. Two abdominal radiologists reviewed retrospectively CEUS cineloops and MR images in 26 HCA. All pathological specimens were reviewed and classified into four subgroups (steatotic or HNF 1? mutated, inflammatory, atypical or ?-catenin mutated, and unspecified). Inflammatory infiltrates were scored, steatosis, and telangiectasia semiquantitatively evaluated. Results. CEUS and MRI features are well correlated: among the 16 inflammatory HCA, 7/16 presented typical imaging features: hypersignal T2, strong arterial enhancement with a centripetal filling, persistent on delayed phase. 6 HCA were classified as steatotic with typical imaging features: a drop out signal, slight arterial enhancement, vanishing on late phase. Four HCA were classified as atypical with an HCC developed in one. Five lesions displayed important steatosis (>50%) without belonging to the HNF1? group. Conclusion. In half cases, inflammatory HCA have specific imaging features well correlated with the amount of telangiectasia and inflammatory infiltrates. An HCA with important amount of steatosis noticed on chemical shift images does not always belong to the HNF1? group. PMID:22811588

  2. Multimodality Functional Imaging in Radiation Therapy Planning: Relationships between Dynamic Contrast-Enhanced MRI, Diffusion-Weighted MRI, and 18F-FDG PET

    PubMed Central

    Mera Iglesias, Moisés; Aramburu Núñez, David; del Olmo Claudio, José Luis; Salvador Gómez, Francisco; Driscoll, Brandon; Coolens, Catherine; Alba Castro, José L.; Muñoz, Victor

    2015-01-01

    Objectives. Biologically guided radiotherapy needs an understanding of how different functional imaging techniques interact and link together. We analyse three functional imaging techniques that can be useful tools for achieving this objective. Materials and Methods. The three different imaging modalities from one selected patient are ADC maps, DCE-MRI, and 18F-FDG PET/CT, because they are widely used and give a great amount of complementary information. We show the relationship between these three datasets and evaluate them as markers for tumour response or hypoxia marker. Thus, vascularization measured using DCE-MRI parameters can determine tumour hypoxia, and ADC maps can be used for evaluating tumour response. Results. ADC and DCE-MRI include information from 18F-FDG, as glucose metabolism is associated with hypoxia and tumour cell density, although 18F-FDG includes more information about the malignancy of the tumour. The main disadvantage of ADC maps is the distortion, and we used only low distorted regions, and extracellular volume calculated from DCE-MRI can be considered equivalent to ADC in well-vascularized areas. Conclusion. A dataset for achieving the biologically guided radiotherapy must include a tumour density study and a hypoxia marker. This information can be achieved using only MRI data or only PET/CT studies or mixing both datasets. PMID:25788972

  3. Additional Value of Diffusion-weighted MRI to Gd-EOB-DTPA-enhanced Hepatic MRI for the Detection of Liver Metastasis: the Difference Depending on the Experience of the Radiologists.

    PubMed

    Fukumoto, Wataru; Nakamura, Yuko; Higaki, Toru; Tatsugami, Fuminari; Iida, Makoto; Awai, Kazuo

    2015-06-01

    This retrospective study was to investigate whether adding diffusion-weighted imaging (DWI) to Gd-EOB-DTPA-enhanced MRI (EOB-MRI) improved the detection of liver metastasis in radiology resident and board-certified radiologist groups. It was approved by our institutional review board. We selected 18 patients with 35 liver metastases and 12 patients without liver tumors. Five board-certified radiologists and 5 radiology residents participated in the observer performance study. Each observer first interpreted T1- and T2-weighted-, plain-, arterial phase-, and hepatobiliary phase images and specified the location of the liver metastases. The software subsequently displayed the DWI images simultaneously and all participants repeated the reading. We used Jackknife alternative free-response receiver operating characteristic (JAFROC) analysis to compare the observer performance in detecting liver metastases. The mean values for the area under the curve (AUC) for EOB-MRI without and with DWI were 0.78 ± 0.13 [standard deviation: SD] and 0.87 ± 0.09, respectively, for the radiology residents, and the difference was statistically significant (p = 0.045). For the board- certified radiologists these values were 0.92 ± 0.02 and 0.96 ± 0.01, respectively, and the difference was not statistically significant (p = 0.092). EOB-MRI with DWI significantly improved the performance of radiology residents in the identification of liver metastases. PMID:26211220

  4. Estimating kinetic parameter maps from dynamic contrast-enhanced MRI using spatial prior knowledge

    E-print Network

    Menze, Bjoern Holger

    Dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging can be used to study microvascular structure in vivo by monitoring the abundance of an injected diffusible contrast agent over time. The resulting spatially ...

  5. Quality assurance in MRI breast screening: comparing signal-to-noise ratio in dynamic contrast-enhanced imaging protocols.

    PubMed

    Kousi, Evanthia; Borri, Marco; Dean, Jamie; Panek, Rafal; Scurr, Erica; Leach, Martin O; Schmidt, Maria A

    2016-01-01

    MRI has been extensively used in breast cancer staging, management and high risk screening. Detection sensitivity is paramount in breast screening, but variations of signal-to-noise ratio (SNR) as a function of position are often overlooked. We propose and demonstrate practical methods to assess spatial SNR variations in dynamic contrast-enhanced (DCE) breast examinations and apply those methods to different protocols and systems. Four different protocols in three different MRI systems (1.5 and 3.0 T) with receiver coils of different design were employed on oil-filled test objects with and without uniformity filters. Twenty 3D datasets were acquired with each protocol; each dataset was acquired in under 60?s, thus complying with current breast DCE guidelines. In addition to the standard SNR calculated on a pixel-by-pixel basis, we propose other regional indices considering the mean and standard deviation of the signal over a small sub-region centred on each pixel. These regional indices include effects of the spatial variation of coil sensitivity and other structured artefacts. The proposed regional SNR indices demonstrate spatial variations in SNR as well as the presence of artefacts and sensitivity variations, which are otherwise difficult to quantify and might be overlooked in a clinical setting. Spatial variations in SNR depend on protocol choice and hardware characteristics. The use of uniformity filters was shown to lead to a rise of SNR values, altering the noise distribution. Correlation between noise in adjacent pixels was associated with data truncation along the phase encoding direction. Methods to characterise spatial SNR variations using regional information were demonstrated, with implications for quality assurance in breast screening and multi-centre trials. PMID:26605957

  6. In Vivo Mn-Enhanced MRI for Early Tumor Detection and Growth Rate Analysis in a Mouse Medulloblastoma Model12

    PubMed Central

    Suero-Abreu, Giselle A.; Praveen Raju, G.; Aristizábal, Orlando; Volkova, Eugenia; Wojcinski, Alexandre; Houston, Edward J.; Pham, Diane; Szulc, Kamila U.; Colon, Daniel; Joyner, Alexandra L.; Turnbull, Daniel H.

    2014-01-01

    Mouse models have increased our understanding of the pathogenesis of medulloblastoma (MB), the most common malignant pediatric brain tumor that often forms in the cerebellum. A major goal of ongoing research is to better understand the early stages of tumorigenesis and to establish the genetic and environmental changes that underlie MB initiation and growth. However, studies of MB progression in mouse models are difficult due to the heterogeneity of tumor onset times and growth patterns and the lack of clinical symptoms at early stages. Magnetic resonance imaging (MRI) is critical for noninvasive, longitudinal, three-dimensional (3D) brain tumor imaging in the clinic but is limited in resolution and sensitivity for imaging early MBs in mice. In this study, high-resolution (100 ?m in 2 hours) and high-throughput (150 ?m in 15 minutes) manganese-enhanced MRI (MEMRI) protocols were optimized for early detection and monitoring of MBs in a Patched-1 (Ptch1) conditional knockout (CKO) model. The high tissue contrast obtained with MEMRI revealed detailed cerebellar morphology and enabled detection of MBs over a wide range of stages including pretumoral lesions as early as 2 to 3 weeks postnatal with volumes close to 0.1 mm3. Furthermore, longitudinal MEMRI allowed noninvasive monitoring of tumors and demonstrated that lesions within and between individuals have different tumorigenic potentials. 3D volumetric studies allowed quantitative analysis of MB tumor morphology and growth rates in individual Ptch1-CKO mice. These results show that MEMRI provides a powerful method for early in vivo detection and longitudinal imaging of MB progression in the mouse brain. PMID:25499213

  7. Quality assurance in MRI breast screening: comparing signal-to-noise ratio in dynamic contrast-enhanced imaging protocols

    NASA Astrophysics Data System (ADS)

    Kousi, Evanthia; Borri, Marco; Dean, Jamie; Panek, Rafal; Scurr, Erica; Leach, Martin O.; Schmidt, Maria A.

    2016-01-01

    MRI has been extensively used in breast cancer staging, management and high risk screening. Detection sensitivity is paramount in breast screening, but variations of signal-to-noise ratio (SNR) as a function of position are often overlooked. We propose and demonstrate practical methods to assess spatial SNR variations in dynamic contrast-enhanced (DCE) breast examinations and apply those methods to different protocols and systems. Four different protocols in three different MRI systems (1.5 and 3.0 T) with receiver coils of different design were employed on oil-filled test objects with and without uniformity filters. Twenty 3D datasets were acquired with each protocol; each dataset was acquired in under 60?s, thus complying with current breast DCE guidelines. In addition to the standard SNR calculated on a pixel-by-pixel basis, we propose other regional indices considering the mean and standard deviation of the signal over a small sub-region centred on each pixel. These regional indices include effects of the spatial variation of coil sensitivity and other structured artefacts. The proposed regional SNR indices demonstrate spatial variations in SNR as well as the presence of artefacts and sensitivity variations, which are otherwise difficult to quantify and might be overlooked in a clinical setting. Spatial variations in SNR depend on protocol choice and hardware characteristics. The use of uniformity filters was shown to lead to a rise of SNR values, altering the noise distribution. Correlation between noise in adjacent pixels was associated with data truncation along the phase encoding direction. Methods to characterise spatial SNR variations using regional information were demonstrated, with implications for quality assurance in breast screening and multi-centre trials.

  8. Contrast enhancement of magnetic resonance imaging (MRI) of polymer gel dosimeter by adding Platinum nano- particles

    NASA Astrophysics Data System (ADS)

    Deyhimihaghighi, N.; Mohd Noor, N.; Soltani, N.; Jorfi, R.; Erfani Haghir, M.; Adenan, M. Z.; Saion, E.; Khandaker, M. U.

    2014-11-01

    In this research different concentrations of Platinum nanoparticles (Pt-NPs) embedded in PAGAT polymer gel and irradiated with Cobalt -60 (60Co). The OD of samples indicate significant dose enhancement caused by Pt-NPs. Different concentrations of Pt-NPs were investigated: 0.5×10-2,1×10-2 2×10-2 and 3×10-2 mg/l and these were presented the enhancement in OD by the factor of 11.56, 27.10, 15.84 and 10.07 respectively. As the mean energy of 60Co is 1.25 MeV and atomic number (Z) of Pt is 78, the predominant effect will be Compton effect and Photoelectric cannot occurred. This work studied the feasibility of using PAGAT polymer gel combined with Pt-NPs as a suitable tool to perform dosimetric investigation of nanoparticles application in radiotherapy as dosimeter and dose enhancer.

  9. Dynamic Contrast-Enhanced MRI Parameters as Biomarkers in Assessing Head and Neck Lesions After Chemoradiotherapy Using a Wide-Bore 3 Tesla Scanner.

    PubMed

    Lerant, Gergely; Sarkozy, Peter; Takacsi-Nagy, Zoltan; Polony, Gabor; Tamas, Laszlo; Toth, Erika; Boer, Andras; Javor, Laszlo; Godeny, Maria

    2015-09-01

    Pilot studies have shown promising results in characterizing head and neck tumors (HNT) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), differentiating between malignant and benign lesions and evaluating changes in response to chemoradiotherapy (CRT). Our aim was to find DCE-MRI parameters, biomarkers in evaluating the post-CRT status. Two hundred and five patients with head and neck lesions were examined with DCE-MRI sequences. The time intensity curves (TIC) were extracted and processed to acquire time-to-peak (TTP), relative maximum enhancement (RME), relative wash-out (RWO), and two new parameters attack and decay. These parameters were analyzed using univariate tests in SPSS (Statistical Package for the Social Sciences, version 17, SPSS Inc. Chicago, USA) to identify parameters that could be used to infer tumor malignancy and post-CRT changes. Multiple parameters of curve characteristics were significantly different between malignant tumors after CRT (MACRT) and changes caused by CRT. The best-performing biomarkers were the attack and the decay. We also found multiple significant (p < 0.05) parameters for both the benign and malignant status as well as pre- and post-CRT status. Our large cohort of data supports the increasing role of DCE-MRI in HNT differentiation, particularly for the assessment of post-CRT status along with accurate morphological imaging. PMID:25920367

  10. Enhanced disease characterization through multi network functional normalization in fMRI.

    PubMed

    Çetin, Mustafa S; Khullar, Siddharth; Damaraju, Eswar; Michael, Andrew M; Baum, Stefi A; Calhoun, Vince D

    2015-01-01

    Conventionally, structural topology is used for spatial normalization during the pre-processing of fMRI. The co-existence of multiple intrinsic networks which can be detected in the resting brain are well-studied. Also, these networks exhibit temporal and spatial modulation during cognitive task vs. rest which shows the existence of common spatial excitation patterns between these identified networks. Previous work (Khullar et al., 2011) has shown that structural and functional data may not have direct one-to-one correspondence and functional activation patterns in a well-defined structural region can vary across subjects even for a well-defined functional task. The results of this study and the existence of the neural activity patterns in multiple networks motivates us to investigate multiple resting-state networks as a single fusion template for functional normalization for multi groups of subjects. We extend the previous approach (Khullar et al., 2011) by co-registering multi group of subjects (healthy control and schizophrenia patients) and by utilizing multiple resting-state networks (instead of just one) as a single fusion template for functional normalization. In this paper we describe the initial steps toward using multiple resting-state networks as a single fusion template for functional normalization. A simple wavelet-based image fusion approach is presented in order to evaluate the feasibility of combining multiple functional networks. Our results showed improvements in both the significance of group statistics (healthy control and schizophrenia patients) and the spatial extent of activation when a multiple resting-state network applied as a single fusion template for functional normalization after the conventional structural normalization. Also, our results provided evidence that the improvement in significance of group statistics lead to better accuracy results for classification of healthy controls and schizophrenia patients. PMID:25873853

  11. Differentiation between multiple liver hemangiomas and liver metastases of gastrinomas: Value of enhanced MRI

    SciTech Connect

    Berger, J.F.; Laissy, J.P.; Limot, O.; Cadiot, G.

    1996-05-01

    Hepatic metastases of neuroendocrine tumors are known to mimic hemangiomas on nonenhanced SE MR sequences. The usefulness of MR examination with gadolinium injection to identify lesions was prospectively evaluated. Nine patients with multiple liver metastases of gastrinomas were compared with six patients showing multiple liver hemangiomas. Patients underwent unenhanced T2-weighted SE, T1-weighted SE, and FLASH sequences, followed by enhanced sequential FLASH sequences and a 5 min delayed T1-weighted SE sequence. On T2-weighted SE sequence, all hemangiomas displayed the same typical morphology as a sharply defined, homogeneous, high signal intensity lesion, but this pattern was also observed for some or all of the lesions in seven of nine patients with gastrinoma metastases. Dynamic FLASH sequences were accurate for lesions larger than 2 cm, hemangiomas displaying a nodular peripheral enhancement with centripetal filling in, and metastases displaying either an initial homogeneous or a regular peripheral enhancement. Precise assessment of lesions smaller than 2 cm remained equivocal. Delayed T1-weighted SE sequence (performed at least 5 min after Gd-chelate injection) was the most accurate technique to identify metastases by showing hypo-or isointensity signal, whereas all hemangiomas were hyperintense. Postcontrast delayed T1-weighted sequence is the primary technique to differentiate equivocal cases of hemangiomas from metastases of gastrinoma. 25 refs., 3 figs., 2 tabs.

  12. Breast MRI fibroglandular volume and parenchymal enhancement in BRCA1 and BRCA2 mutation carriers before and immediately after risk-reducing salpingo-oophorectomy.

    PubMed

    DeLeo, Michael J; Domchek, Susan M; Kontos, Despina; Conant, Emily; Chen, Jinbo; Weinstein, Susan

    2015-03-01

    OBJECTIVE. The purpose of this article is to assess the difference in fibroglandular volume and background parenchymal enhancement in BRCA1 and BRCA2 mutation carriers on contrast-enhanced breast MRI (CE-MRI) performed before and immediately after risk-reducing salpingo-oophorectomy (RRSO). MATERIALS AND METHODS. We retrospectively compared fibroglandular volume and background parenchymal enhancement in 55 female BRCA1 and BRCA2 mutation carriers before and after RRSO using standard BI-RADS categories and a paired Wilcoxon and Mann-Whitney U test. A two-sample Wilcoxon test was performed to compare fibroglandular volume and background parenchymal enhancement in women with and without subsequent breast cancer diagnosis on follow-up. RESULTS. The median time to post-RRSO CE-MRI was 8 months (range, 1-40 months). There was no difference in fibroglandular volume before and after RRSO (p = 0.65). The mean background parenchymal enhancement was 2.5 (range, 1-4) before and 1.5 (range, 1-4) after RRSO (overall range, -2.5 to 1.5; p = 0.0001). Breast cancer was detected in nine women at a median time of 4.8 years (range, 1.8-13.3 years) after RRSO. For women who received a diagnosis of breast cancer after RRSO compared with those who did not, mean background parenchymal enhancement before RRSO was 3 (range, 2-4) versus 2.5 (range, 1-4; p = 0.001), and mean background parenchymal enhancement after RRSO was 2.5 (range, 1.5-4) versus 1.5 (range 2-4; p = 0.0018). There was no difference in fibroglandular volume before and after RRSO. CONCLUSION. In BRCA1 and BRCA2 mutation carriers, we observed a significant reduction in background parenchymal enhancement on the first CE-MRI after RRSO and no significant change in fibroglandular volume. Higher background parenchymal enhancement before and after RRSO was observed in women who subsequently received a diagnosis of breast cancer. This suggests that background parenchymal enhancement, rather than fibro-glandular volume, may be a more sensitive imaging biomarker of breast cancer risk. PMID:25714301

  13. Detection of cortical gray matter lesion in the late phase of mild hypoxic-ischemic injury by manganese-enhanced MRI.

    PubMed

    Yang, Jian; Wu, Ed X

    2008-01-15

    Noncystic periventricular leukomalacia (PVL) in premature infants is becoming a predominant lesion form. However, detection of the gray matter (GM) lesions involved in this disease, which closely relate to the later cognitive and behavioral deficits, is challenging because of their subtle and transient nature observed by conventional MRI. This study evaluated manganese-enhanced MRI (MEMRI) for detecting such GM lesions in 7-day-old rats with mild hypoxic-ischemic (H-I) insult, a characteristic model of noncystic PVL. Group 1 (n=6) and Group 2 (n=8) were administered intraperitoneally with MnCl(2) at hour 3 and day 7 after H-I insult, respectively. Control Group (n=6) received no MnCl(2). T1-, T2- and diffusion-weighted imaging (T1WI, T2WI and DWI, respectively) was performed. Animals were sacrificed for H&E staining, and immunohistochemical staining for glutamine synthetase (GS) and Mn-superoxide dismutase (Mn-SOD), which are two Mn-binding enzymes against glutamate toxicity and oxidative stress respectively in neurodegeneration. In Control Group, MRI appearance of H-I lesions normalized by day 7 after H-I insult. In Group 1, MEMRI provided the enhanced and prolonged GM lesion detection from day 3 up to day 21. In Group 2, similar Mn enhancement was observed, enabling day 8 detection of GM lesions that were invisible before Mn injection at day 7. These in vivo Mn-induced GM lesion enhancements were found to correlate with increased immunoactivities of GS and Mn-SOD. These findings suggest the potential utility of MEMRI in detecting the GM lesions that are otherwise undetectable using the conventional MRI techniques in late phase of mild H-I injury. PMID:17949999

  14. Connectivity-based fixel enhancement: Whole-brain statistical analysis of diffusion MRI measures in the presence of crossing fibres

    PubMed Central

    Raffelt, David A.; Smith, Robert E.; Ridgway, Gerard R.; Tournier, J-Donald; Vaughan, David N.; Rose, Stephen; Henderson, Robert; Connelly, Alan

    2015-01-01

    In brain regions containing crossing fibre bundles, voxel-average diffusion MRI measures such as fractional anisotropy (FA) are difficult to interpret, and lack within-voxel single fibre population specificity. Recent work has focused on the development of more interpretable quantitative measures that can be associated with a specific fibre population within a voxel containing crossing fibres (herein we use fixel to refer to a specific fibre population within a single voxel). Unfortunately, traditional 3D methods for smoothing and cluster-based statistical inference cannot be used for voxel-based analysis of these measures, since the local neighbourhood for smoothing and cluster formation can be ambiguous when adjacent voxels may have different numbers of fixels, or ill-defined when they belong to different tracts. Here we introduce a novel statistical method to perform whole-brain fixel-based analysis called connectivity-based fixel enhancement (CFE). CFE uses probabilistic tractography to identify structurally connected fixels that are likely to share underlying anatomy and pathology. Probabilistic connectivity information is then used for tract-specific smoothing (prior to the statistical analysis) and enhancement of the statistical map (using a threshold-free cluster enhancement-like approach). To investigate the characteristics of the CFE method, we assessed sensitivity and specificity using a large number of combinations of CFE enhancement parameters and smoothing extents, using simulated pathology generated with a range of test-statistic signal-to-noise ratios in five different white matter regions (chosen to cover a broad range of fibre bundle features). The results suggest that CFE input parameters are relatively insensitive to the characteristics of the simulated pathology. We therefore recommend a single set of CFE parameters that should give near optimal results in future studies where the group effect is unknown. We then demonstrate the proposed method by comparing apparent fibre density between motor neurone disease (MND) patients with control subjects. The MND results illustrate the benefit of fixel-specific statistical inference in white matter regions that contain crossing fibres. PMID:26004503

  15. Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated Mn x Fe(1-x) O nanoparticles.

    PubMed

    Chen, Wei; Lu, Fang; Chen, Chiao-Chi V; Mo, Kuan-Chi; Hung, Yann; Guo, Zhi-Xuan; Lin, Chia-Hui; Lin, Ming-Huang; Lin, Yu-Hsuan; Chang, Chen; Mou, Chung-Yuan

    2013-09-01

    In this work, we report a monodisperse bifunctional nanoparticle system, MIO@SiO2 -RITC, as an MRI contrast agent [core, manganese iron oxide (MIO); shell, amorphous silica conjugated with rhodamine B isothiocyanate (RITC)]. It was prepared by thermal decomposition and modified microemulsion methods. The nanoparticles with varying iron to manganese ratios displayed different saturated magnetizations and relaxivities. In vivo MRI of rats injected intravenously with MIO@SiO2-RITC nanoparticles exhibited enhancement of the T1 contrast in brain tissue, in particular a time-delayed enhancement in the hippocampus, pituitary gland, striatum and cerebellum. This is attributable to the gradual degradation of MIO@SiO2-RITC nanoparticles in the liver, resulting in the slow release of manganese(II) [Mn(II)] into the blood pool and, subsequently, accumulation in the brain tissue. Thus, T1-weighted contrast enhancement was clearly detected in the anatomic structure of the brain as time progressed. In addition, T2*-weighted images of the liver showed a gradual darkening effect. Here, we demonstrate the concept of the slow release of Mn(II) for neuroimaging. This new nanoparticle-based manganese contrast agent allows one simple intravenous injection (rather than multiple infusions) of Mn(II) precursor, and results in delineation of the detailed anatomic neuroarchitecture in MRI; hence, this provides the advantage of the long-term study of neural function. PMID:23526743

  16. Multi-Parametric MRI and Texture Analysis to Visualize Spatial Histologic Heterogeneity and Tumor Extent in Glioblastoma

    PubMed Central

    Hu, Leland S.; Ning, Shuluo; Eschbacher, Jennifer M.; Gaw, Nathan; Dueck, Amylou C.; Smith, Kris A.; Nakaji, Peter; Plasencia, Jonathan; Ranjbar, Sara; Price, Stephen J.; Tran, Nhan; Loftus, Joseph; Jenkins, Robert; O’Neill, Brian P.; Elmquist, William; Baxter, Leslie C.; Gao, Fei; Frakes, David; Karis, John P.; Zwart, Christine; Swanson, Kristin R.; Sarkaria, Jann; Wu, Teresa

    2015-01-01

    Background Genetic profiling represents the future of neuro-oncology but suffers from inadequate biopsies in heterogeneous tumors like Glioblastoma (GBM). Contrast-enhanced MRI (CE-MRI) targets enhancing core (ENH) but yields adequate tumor in only ~60% of cases. Further, CE-MRI poorly localizes infiltrative tumor within surrounding non-enhancing parenchyma, or brain-around-tumor (BAT), despite the importance of characterizing this tumor segment, which universally recurs. In this study, we use multiple texture analysis and machine learning (ML) algorithms to analyze multi-parametric MRI, and produce new images indicating tumor-rich targets in GBM. Methods We recruited primary GBM patients undergoing image-guided biopsies and acquired pre-operative MRI: CE-MRI, Dynamic-Susceptibility-weighted-Contrast-enhanced-MRI, and Diffusion Tensor Imaging. Following image coregistration and region of interest placement at biopsy locations, we compared MRI metrics and regional texture with histologic diagnoses of high- vs low-tumor content (?80% vs <80% tumor nuclei) for corresponding samples. In a training set, we used three texture analysis algorithms and three ML methods to identify MRI-texture features that optimized model accuracy to distinguish tumor content. We confirmed model accuracy in a separate validation set. Results We collected 82 biopsies from 18 GBMs throughout ENH and BAT. The MRI-based model achieved 85% cross-validated accuracy to diagnose high- vs low-tumor in the training set (60 biopsies, 11 patients). The model achieved 81.8% accuracy in the validation set (22 biopsies, 7 patients). Conclusion Multi-parametric MRI and texture analysis can help characterize and visualize GBM’s spatial histologic heterogeneity to identify regional tumor-rich biopsy targets. PMID:26599106

  17. Cocaine-induced locomotor sensitization in rats correlates with nucleus accumbens activity on manganese-enhanced MRI.

    PubMed

    Perrine, Shane A; Ghoddoussi, Farhad; Desai, Kirtan; Kohler, Robert J; Eapen, Ajay T; Lisieski, Michael J; Angoa-Perez, Mariana; Kuhn, Donald M; Bosse, Kelly E; Conti, Alana C; Bissig, David; Berkowitz, Bruce A

    2015-11-01

    A long-standing goal of substance abuse research has been to link drug-induced behavioral outcomes with the activity of specific brain regions to understand the neurobiology of addiction behaviors and to search for drug-able targets. Here, we tested the hypothesis that cocaine produces locomotor (behavioral) sensitization that correlates with increased calcium channel-mediated neuroactivity in brain regions linked with drug addiction, such as the nucleus accumbens (NAC), anterior striatum (AST) and hippocampus, as measured using manganese-enhanced MRI (MEMRI). Rats were treated with cocaine for 5?days, followed by a 2-day drug-free period. The following day, locomotor sensitization was quantified as a metric of cocaine-induced neuroplasticity in the presence of manganese. Immediately following behavioral testing, rats were examined for changes in calcium channel-mediated neuronal activity in the NAC, AST, hippocampus and temporalis muscle, which was associated with behavioral sensitization using MEMRI. Cocaine significantly increased locomotor activity and produced behavioral sensitization compared with saline treatment of control rats. A significant increase in MEMRI signal intensity was determined in the NAC, but not AST or hippocampus, of cocaine-treated rats compared with saline-treated control rats. Cocaine did not increase signal intensity in the temporalis muscle. Notably, in support of our hypothesis, behavior was significantly and positively correlated with MEMRI signal intensity in the NAC. As neuronal uptake of manganese is regulated by calcium channels, these results indicate that MEMRI is a powerful research tool to study neuronal activity in freely behaving animals and to guide new calcium channel-based therapies for the treatment of cocaine abuse and dependence. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26411897

  18. 7T MRI in natalizumab-associated PML and ongoing MS disease activity

    PubMed Central

    Sinnecker, Tim; Othman, Jalal; Kühl, Marc; Mekle, Ralf; Selbig, Inga; Niendorf, Thoralf; Kunkel, Annett; Wienecke, Peter; Kern, Peter; Faiss, Juergen; Wuerfel, Jens

    2015-01-01

    Objective: To assess the ability of ultra-high-field MRI to distinguish early progressive multifocal leukoencephalopathy (PML) from multiple sclerosis (MS) lesions in a rare case of simultaneous presentation of natalizumab–associated PML and ongoing MS activity. Methods: Advanced neuroimaging including 1.5T, 3T, and 7T MRI with a spatial resolution of up to 0.08 mm3 was performed. Results: 7T MRI differentiated between PML-related and MS-related brain damage in vivo. Ring-enhancing MS plaques displayed a central vein, whereas confluent PML lesions were preceded by punctate or milky way–like T2 lesions. Conclusions: Given the importance of early diagnosis of treatment-associated PML, future systematic studies are warranted to assess the value of highly resolving MRI in differentiating between early PML- and MS-induced brain parenchymal lesions. PMID:26568970

  19. Noninvasive monitoring of radiotherapy-induced microvascular changes using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in a colorectal tumor model

    SciTech Connect

    Ceelen, Wim . E-mail: Wim.ceelen@ugent.be; Smeets, Peter; Backes, Walter; Van Damme, Nancy; Boterberg, Tom; Demetter, Pieter; Bouckenooghe, Isabel; De Visschere, Marieke; Peeters, Marc; Pattyn, Piet

    2006-03-15

    Purpose: To examine dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with a macromolecular contrast agent (P792) to visualize effects of radiotherapy (RT) on microvascular leakage in a colorectal cancer model. Methods and Materials: CC531 tumors were induced in WAG/Rij rats. DCE-MRI was performed before and 5 days after 5 x 5 Gy of RT and parametric maps generated of the endothelial transfer constant (K{sup trans} ) and the fractional interstitial space (V{sub e} ) according to the Tofts model. Tissue pO{sub 2} mapping was performed in each tumor core and rim before and after RT. Microvessel density (MVD), vascular endothelial growth factor (VEGF) expression, and pimonidazole hypoxia staining were compared with a control group of tumor-bearing rats. Results: Mean K{sup trans} and v{sub e} were significantly reduced after RT in all tumor regions. Mean pO{sub 2} was 6.8 mm Hg before RT vs. 7.7 mm Hg after RT (p < 0.001) in the tumor rim and 3.5 mm Hg before RT vs. 4.4 mm Hg after RT (p < 0.001) in the tumor core. Mean MVD in the tumor rim was 10.4 in the RT treated group vs. 16.9 in the control group (p = 0.061). VEGF expression was significantly higher in RT-treated rats. After RT, no correlation was found between DCE-MRI parameters and histologic parameters. A correlation was seen after RT between pO{sub 2} and K{sup trans} (r -0.57, p = 0.08) and between pO{sub 2} and v{sub e} (r = -0.65, p = 0.04). Conclusions: Dynamic contrast-enhanced-MRI with P792 allows quantification of microvascular changes in this colorectal model. RT significantly reduces neovascular leakage and enhances tissue oxygenation and VEGF expression. After RT, DCE-MRI parameters are related to tumor pO{sub 2}, but not to MVD or VEGF expression.

  20. Dynamic Contrast-Enhanced MRI in the Study of Brain Tumors. Comparison Between the Extended Tofts-Kety Model and a Phenomenological Universalities (PUN) Algorithm.

    PubMed

    Bergamino, Maurizio; Barletta, Laura; Castellan, Lucio; Mancardi, Gianluigi; Roccatagliata, Luca

    2015-12-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a well-established technique for studying blood-brain barrier (BBB) permeability that allows measurements to be made for a wide range of brain pathologies, including multiple sclerosis and brain tumors (BT). This latter application is particularly interesting, because high-grade gliomas are characterized by increased microvascular permeability and a loss of BBB function due to the structural abnormalities of the endothelial layer. In this study, we compared the extended Tofts-Kety (ETK) model and an extended derivate class from phenomenological universalities called EU1 in 30 adult patients with different BT grades. A total of 75 regions of interest were manually drawn on the MRI and subsequently analyzed using the ETK and EU1 algorithms. Significant linear correlations were found among the parameters obtained by these two algorithms. The means of R (2) obtained using ETK and EU1 models for high-grade tumors were 0.81 and 0.91, while those for low-grade tumors were 0.82 and 0.85, respectively; therefore, these two models are equivalent. In conclusion, we can confirm that the application of the EU1 model to the DCE-MRI experimental data might be a useful alternative to pharmacokinetic models in the study of BT, because the analytic results can be generated more quickly and easily than with the ETK model. PMID:25776769

  1. Automatic classification of scar tissue in late gadolinium enhancement cardiac MRI for the assessment of left-atrial wall injury after radiofrequency ablation

    NASA Astrophysics Data System (ADS)

    Perry, Daniel; Morris, Alan; Burgon, Nathan; McGann, Christopher; MacLeod, Robert; Cates, Joshua

    2012-03-01

    Radiofrequency ablation is a promising procedure for treating atrial fibrillation (AF) that relies on accurate lesion delivery in the left atrial (LA) wall for success. Late Gadolinium Enhancement MRI (LGE MRI) at three months post-ablation has proven effective for noninvasive assessment of the location and extent of scar formation, which are important factors for predicting patient outcome and planning of redo ablation procedures. We have developed an algorithm for automatic classification in LGE MRI of scar tissue in the LA wall and have evaluated accuracy and consistency compared to manual scar classifications by expert observers. Our approach clusters voxels based on normalized intensity and was chosen through a systematic comparison of the performance of multivariate clustering on many combinations of image texture. Algorithm performance was determined by overlap with ground truth, using multiple overlap measures, and the accuracy of the estimation of the total amount of scar in the LA. Ground truth was determined using the STAPLE algorithm, which produces a probabilistic estimate of the true scar classification from multiple expert manual segmentations. Evaluation of the ground truth data set was based on both inter- and intra-observer agreement, with variation among expert classifiers indicating the difficulty of scar classification for a given a dataset. Our proposed automatic scar classification algorithm performs well for both scar localization and estimation of scar volume: for ground truth datasets considered easy, variability from the ground truth was low; for those considered difficult, variability from ground truth was on par with the variability across experts.

  2. Intra-Tumor Distribution and Test-Retest Comparisons of Physiological Parameters quantified by Dynamic Contrast-Enhanced MRI in Rat U251 Glioma

    PubMed Central

    Aryal, Madhava P.; Nagaraja, Tavarekere N.; Brown, Stephen L.; Lu, Mei; Bagher-Ebadian, Hassan; Ding, Guangliang; Panda, Swayamprava; Keenan, Kelly; Cabral, Glauber; Mikkelsen, Tom; Ewing, James R.

    2014-01-01

    The distribution of dynamic contrast enhanced MRI (DCE-MRI) parametric estimates in a rat U251 glioma model was analyzed. Using Magnevist as contrast agent (CA), 17 nude rats implanted with U251 cerebral glioma were studied by DCE-MRI twice in a 24 h interval. A data-driven analysis selected one of three models to estimate either: 1) CA plasma volume (vp), 2) vp and forward volume transfer constant (Ktrans; or 3) vp, Ktrans, and interstitial volume fraction (ve), constituting Models 1, 2 and 3, respectively. CA interstitial distribution volume (VD) was estimated in Model 3 regions by Logan plots. Regions of interest (ROIs) were selected by model. In the Model 3 ROI, descriptors of parameter distributions – mean, median, variance and skewness – were calculated and compared between the two time points for repeatability. All distributions of parametric estimates in Model 3 ROIs were positively skewed. Test-retest differences between population summaries for any parameter were not significant (p?0.10; Wilcoxon signed-rank and paired t tests). This and similar measures of parametric distribution and test-retest variance from other tumor models can be used to inform the choice of biomarkers that best summarize tumor status and treatment effects. PMID:25125367

  3. An investigation into the effects of temporal resolution on hepatic dynamic contrast-enhanced MRI in volunteers and in patients with hepatocellular carcinoma

    NASA Astrophysics Data System (ADS)

    Gill, Andrew B.; Black, Richard T.; Bowden, David J.; Priest, Andrew N.; Graves, Martin J.; Lomas, David J.

    2014-06-01

    This study investigated the effect of temporal resolution on the dual-input pharmacokinetic (PK) modelling of dynamic contrast-enhanced MRI (DCE-MRI) data from normal volunteer livers and from patients with hepatocellular carcinoma. Eleven volunteers and five patients were examined at 3 T. Two sections, one optimized for the vascular input functions (VIF) and one for the tissue, were imaged within a single heart-beat (HB) using a saturation-recovery fast gradient echo sequence. The data was analysed using a dual-input single-compartment PK model. The VIFs and/or uptake curves were then temporally sub-sampled (at interval ?t = [2-20] s) before being subject to the same PK analysis. Statistical comparisons of tumour and normal tissue PK parameter values using a 5% significance level gave rise to the same study results when temporally sub-sampling the VIFs to HB < ?t <4 s. However, sub-sampling to ?t > 4 s did adversely affect the statistical comparisons. Temporal sub-sampling of just the liver/tumour tissue uptake curves at ?t ? 20 s, whilst using high temporal resolution VIFs, did not substantially affect PK parameter statistical comparisons. In conclusion, there is no practical advantage to be gained from acquiring very high temporal resolution hepatic DCE-MRI data. Instead the high temporal resolution could be usefully traded for increased spatial resolution or SNR.

  4. An investigation into the effects of temporal resolution on hepatic dynamic contrast-enhanced MRI in volunteers and in patients with hepatocellular carcinoma.

    PubMed

    Gill, Andrew B; Black, Richard T; Bowden, David J; Priest, Andrew N; Graves, Martin J; Lomas, David J

    2014-06-21

    This study investigated the effect of temporal resolution on the dual-input pharmacokinetic (PK) modelling of dynamic contrast-enhanced MRI (DCE-MRI) data from normal volunteer livers and from patients with hepatocellular carcinoma. Eleven volunteers and five patients were examined at 3 T. Two sections, one optimized for the vascular input functions (VIF) and one for the tissue, were imaged within a single heart-beat (HB) using a saturation-recovery fast gradient echo sequence. The data was analysed using a dual-input single-compartment PK model. The VIFs and/or uptake curves were then temporally sub-sampled (at interval ?t = [2-20] s) before being subject to the same PK analysis. Statistical comparisons of tumour and normal tissue PK parameter values using a 5% significance level gave rise to the same study results when temporally sub-sampling the VIFs to HB < ?t <4 s. However, sub-sampling to ?t > 4 s did adversely affect the statistical comparisons. Temporal sub-sampling of just the liver/tumour tissue uptake curves at ?t ? 20 s, whilst using high temporal resolution VIFs, did not substantially affect PK parameter statistical comparisons. In conclusion, there is no practical advantage to be gained from acquiring very high temporal resolution hepatic DCE-MRI data. Instead the high temporal resolution could be usefully traded for increased spatial resolution or SNR. PMID:24862216

  5. In vivo monitoring of sorafenib therapy effects on experimental prostate carcinomas using dynamic contrast-enhanced MRI and macromolecular contrast media

    PubMed Central

    Schwarz, Bettina; Paprottka, Philipp M.; Sourbron, Steven; von Einem, Jobst C.; Dietrich, Olaf; Hinkel, Rabea; Clevert, Dirk A.; Bruns, Christiane J.; Reiser, Maximilian F.; Nikolaou, Konstantin; Wintersperger, Bernd J.

    2013-01-01

    Abstract Purpose: To investigate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with macromolecular contrast media (MMCM) to monitor the effects of the multikinase inhibitor sorafenib on subcutaneous prostate carcinomas in rats with immunohistochemical validation. Materials and methods: Copenhagen rats, implanted with prostate carcinoma allografts, were randomized to the treatment group (n?=?8) or the control group (n?=?8). DCE-MRI with albumin-(Gd-DTPA)35 was performed at baseline and after 1 week using a clinical 3-Tesla system. The treatment group received sorafenib, 10?mg/kg body weight daily. Kinetic analysis yielded quantitative parameters of tumor endothelial permeability–surface area product (PS; ml/100?ml/min) and fractional blood volume (Vb, %). Tumors were harvested on day 7 for immunohistochemical analysis. Results: In sorafenib-treated tumors, PS (0.62?±?0.20 vs 0.08?±?0.09?ml/100?ml/min; P?MRI-assayed fractional blood volume Vb showed a highly significant correlation with tumor vascularity (RECA-1; r?=?0.87, P?MRI with MMCM demonstrated good, significant correlations with the immunohistochemically assessed antiangiogenic, antiproliferative, and proapoptotic effects of a 1-week, daily treatment course of sorafenib on experimental prostate carcinoma allografts. PMID:24380871

  6. Water-Exchange-Modified Kinetic Parameters from Dynamic Contrast-Enhanced MRI as Prognostic Biomarkers of Survival in Advanced Hepatocellular Carcinoma Treated with Antiangiogenic Monotherapy

    PubMed Central

    Lee, Sang Ho; Hayano, Koichi; Zhu, Andrew X.; Sahani, Dushyant V.; Yoshida, Hiroyuki

    2015-01-01

    Background To find prognostic biomarkers in pretreatment dynamic contrast-enhanced MRI (DCE-MRI) water-exchange-modified (WX) kinetic parameters for advanced hepatocellular carcinoma (HCC) treated with antiangiogenic monotherapy. Methods Twenty patients with advanced HCC underwent DCE-MRI and were subsequently treated with sunitinib. Pretreatment DCE-MRI data on advanced HCC were analyzed using five different WX kinetic models: the Tofts-Kety (WX-TK), extended TK (WX-ETK), two compartment exchange, adiabatic approximation to tissue homogeneity (WX-AATH), and distributed parameter (WX-DP) models. The total hepatic blood flow, arterial flow fraction (?), arterial blood flow (BFA), portal blood flow, blood volume, mean transit time, permeability-surface area product, fractional interstitial volume (vI), extraction fraction, mean intracellular water molecule lifetime (?C), and fractional intracellular volume (vC) were calculated. After receiver operating characteristic analysis with leave-one-out cross-validation, individual parameters for each model were assessed in terms of 1-year-survival (1YS) discrimination using Kaplan-Meier analysis, and association with overall survival (OS) using univariate Cox regression analysis with permutation testing. Results The WX-TK-model-derived ? (P = 0.022) and vI (P = 0.010), and WX-ETK-model-derived ?C (P = 0.023) and vC (P = 0.042) were statistically significant prognostic biomarkers for 1YS. Increase in the WX-DP-model-derived BFA (P = 0.025) and decrease in the WX-TK, WX-ETK, WX-AATH, and WX-DP-model-derived vC (P = 0.034, P = 0.038, P = 0.028, P = 0.041, respectively) were significantly associated with an increase in OS. Conclusions The WX-ETK-model-derived vC was an effective prognostic biomarker for advanced HCC treated with sunitinib. PMID:26366997

  7. Alertness in Young Healthy Subjects: An fMRI Study of Brain Region Interactivity Enhanced by a Warning Signal

    ERIC Educational Resources Information Center

    Perin, B.; Godefroy, O.; Fall, S.; de Marco, G.

    2010-01-01

    An effective connectivity study was carried out on 16 young, healthy subjects performing an alertness task. The objective of this study was to develop and to evaluate a putative network model of alertness by adapting structural equation modeling to fMRI data. This study was designed to evaluate the directed interactivity of an attentional network…

  8. Dynamic Contrast-Enhanced MRI in Head-and-Neck Cancer: The Impact of Region of Interest Selection on the Intra- and Interpatient Variability of Pharmacokinetic Parameters

    SciTech Connect

    Craciunescu, Oana I.; Yoo, David S.; Cleland, Esi; Muradyan, Naira; Carroll, Madeline D.; MacFall, James R.; Barboriak, Daniel P.; Brizel, David M.

    2012-03-01

    Purpose: Dynamic contrast-enhanced (DCE) MRI-extracted parameters measure tumor microvascular physiology and are usually calculated from an intratumor region of interest (ROI). Optimal ROI delineation is not established. The valid clinical use of DCE-MRI requires that the variation for any given parameter measured within a tumor be less than that observed between tumors in different patients. This work evaluates the impact of tumor ROI selection on the assessment of intra- and interpatient variability. Method and Materials: Head and neck cancer patients received initial targeted therapy (TT) treatment with erlotinib and/or bevacizumab, followed by radiotherapy and concurrent cisplatin with synchronous TT. DCE-MRI data from Baseline and the end of the TT regimen (Lead-In) were analyzed to generate the vascular transfer function (K{sup trans}), the extracellular volume fraction (v{sub e}), and the initial area under the concentration time curve (iAUC{sub 1min}). Four ROI sampling strategies were used: whole tumor or lymph node (Whole), the slice containing the most enhancing voxels (SliceMax), three slices centered in SliceMax (Partial), and the 5% most enhancing contiguous voxels within SliceMax (95Max). The average coefficient of variation (aCV) was calculated to establish intrapatient variability among ROI sets and interpatient variability for each ROI type. The average ratio between each intrapatient CV and the interpatient CV was calculated (aRCV). Results: Baseline primary/nodes aRCVs for different ROIs not including 95Max were, for all three MR parameters, in the range of 0.14-0.24, with Lead-In values between 0.09 and 0.2, meaning a low intrapatient vs. interpatient variation. For 95Max, intrapatient CVs approximated interpatient CVs, meaning similar data dispersion and higher aRCVs (0.6-1.27 for baseline) and 0.54-0.95 for Lead-In. Conclusion: Distinction between different patient's primary tumors and/or nodes cannot be made using 95Max ROIs. The other three strategies are viable and equivalent for using DCE-MRI to measure head and neck cancer physiology.

  9. Multiphasic Enhancement Patterns of Small Renal Masses (?4 cm) on Preoperative Computed Tomography: Utility for Distinguishing Subtypes of Renal Cell Carcinoma, Angiomyolipoma, and Oncocytoma

    PubMed Central

    Pierorazio, Phillip M.; Hyams, Elias S.; Tsai, Salina; Feng, Zhaoyong; Trock, Bruce J.; Mullins, Jeffrey K.; Johnson, Pamela T.; Fishman, Elliot K.; Allaf, Mohamad E.

    2015-01-01

    OBJECTIVE To analyze the enhancement patterns of small renal masses (SRMs) during 4-phase computed tomography (CT) imaging to predict histology. METHODS One-hundred consecutive patients with SRMs and 4-phase preoperative CT imaging, who underwent extirpative surgery with a pathologic diagnosis of renal cell carcinoma (RCC), angiomyolipoma (AML), or oncocytoma, were identified from a single institution. An expert radiologist, blinded to histologic results, retrospectively recorded tumor size, RENAL (radius, exophytic/endophytic properties of the tumor, nearness of tumor deepest portion to the collecting system or sinus, anterior/posterior descriptor, and the location relative to polar lines) nephrometry score, tumor attenuation, and the renal cortex on all 4 acquisitions (precontrast, corticomedullary, nephrogenic, and delayed density). RESULTS Pathologic diagnoses included 48 clear-cell RCCs (ccRCCs), 22 papillary RCCs, 10 chromophobe RCCs, 13 oncocytomas, and 7 AMLs. There was no significant difference in median tumor size (P = .8), nephrometry score (P = .98), or anatomic location (P >.2) among histologies. Significant differences were noted in peak enhancement (P <.001) and phase-specific enhancement (P <.007) by histology. Papillary RCCs demonstrated a distinct enhancement pattern, with a peak Hounsfield unit (HU) of 56, and greatest enhancement during the NG and delayed phases. The highest peak HU were demonstrated by ccRCC (117 HU) and oncocytoma (125 HU); ccRCC more often peaked in the corticomedullary phase, whereas oncocytoma peaked in the nephrogenic phase. CONCLUSION In a series of patients with SRMs undergoing 4-phase CT, tumor histologies demonstrated distinct enhancement patterns. Thus, preoperative 4-phase CT imaging may provide useful information regarding pathologic diagnosis in patients undergoing extirpative surgery. PMID:23601445

  10. Accurate High-Resolution Measurements of 3-D Tissue Dynamics With Registration-Enhanced Displacement Encoded MRI

    PubMed Central

    Merchant, Samer S.; Hsu, Edward W.

    2014-01-01

    Displacement fields are important to analyze deformation, which is associated with functional and material tissue properties often used as indicators of health. Magnetic resonance imaging (MRI) techniques like DENSE and image registration methods like Hyperelastic Warping have been used to produce pixel-level deformation fields that are desirable in high-resolution analysis. However, DENSE can be complicated by challenges associated with image phase unwrapping, in particular offset determination. On the other hand, Hyperelastic Warping can be hampered by low local image contrast. The current work proposes a novel approach for measuring tissue displacement with both DENSE and Hyperelastic Warping, incorporating physically accurate displacements obtained by the latter to improve phase characterization in DENSE. The validity of the proposed technique is demonstrated using numerical and physical phantoms, and in vivo small animal cardiac MRI. PMID:24771572

  11. Chest MRI

    MedlinePLUS

    Nuclear magnetic resonance - chest; Magnetic resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI ... radiation. To date, no side effects from the magnetic fields and radio waves have been reported. The ...

  12. Enhancement of Temporal Resolution and BOLD Sensitivity in Real-Time fMRI using Multi-Slab Echo-Volumar Imaging

    PubMed Central

    Posse, Stefan; Ackley, Elena; Mutihac, Radu; Rick, Jochen; Shane, Matthew; Murray-Krezan, Cristina; Zaitsev, Maxim; Speck, Oliver

    2012-01-01

    In this study, a new approach to high-speed fMRI using multi-slab echo-volumar imaging (EVI) is developed that minimizes geometrical image distortion and spatial blurring, and enables nonaliased sampling of physiological signal fluctuation to increase BOLD sensitivity compared to conventional echo-planar imaging (EPI). Real-time fMRI using whole brain 4-slab EVI with 286 ms temporal resolution (4 mm isotropic voxel size) and partial brain 2-slab EVI with 136 ms temporal resolution (4×4×6 mm3 voxel size) was performed on a clinical 3 Tesla MRI scanner equipped with 12-channel head coil. Four-slab EVI of visual and motor tasks significantly increased mean (visual: 96%, motor: 66%) and maximum t-score (visual: 263%, motor: 124%) and mean (visual: 59%, motor: 131%) and maximum (visual: 29%, motor: 67%) BOLD signal amplitude compared with EPI. Time domain moving average filtering (2 s width) to suppress physiological noise from cardiac and respiratory fluctuations further improved mean (visual: 196%, motor: 140%) and maximum (visual: 384%, motor: 200%) t-scores and increased extents of activation (visual: 73%, motor: 70%) compared to EPI. Similar sensitivity enhancement, which is attributed to high sampling rate at only moderately reduced temporal signal-to-noise ratio (mean: ? 52%) and longer sampling of the BOLD effect in the echo-time domain compared to EPI, was measured in auditory cortex. Two-slab EVI further improved temporal resolution for measuring task-related activation and enabled mapping of five major resting state networks (RSNs) in individual subjects in 5 min scans. The bilateral sensorimotor, the default mode and the occipital RSNs were detectable in time frames as short as 75 s. In conclusion, the high sampling rate of real-time multi-slab EVI significantly improves sensitivity for studying the temporal dynamics of hemodynamic responses and for characterizing functional networks at high field strength in short measurement times. PMID:22398395

  13. Dynamic contrast-enhanced MRI texture analysis for pretreatment prediction of clinical and pathological response to neoadjuvant chemotherapy in patients with locally advanced breast cancer.

    PubMed

    Teruel, Jose R; Heldahl, Mariann G; Goa, Pål E; Pickles, Martin; Lundgren, Steinar; Bathen, Tone F; Gibbs, Peter

    2014-08-01

    The aim of this study was to investigate the potential of texture analysis, applied to dynamic contrast-enhanced MRI (DCE-MRI), to predict the clinical and pathological response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer (LABC) before NAC is started. Fifty-eight patients with LABC were classified on the basis of their clinical response according to the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines after four cycles of NAC, and according to their pathological response after surgery. T1 -weighted DCE-MRI with a temporal resolution of 1?min was acquired on a 3-T Siemens Trio scanner using a dedicated four-channel breast coil before the onset of treatment. Each lesion was segmented semi-automatically using the 2-min post-contrast subtracted image. Sixteen texture features were obtained at each non-subtracted post-contrast time point using a gray level co-occurrence matrix. Appropriate statistical analyses were performed and false discovery rate-based q values were reported to correct for multiple comparisons. Statistically significant results were found at 1-3?min post-contrast for various texture features for the prediction of both the clinical and pathological response. In particular, eight texture features were found to be statistically significant at 2?min post-contrast, the most significant feature yielding an area under the curve (AUC) of 0.77 for response prediction for stable disease versus complete responders after four cycles of NAC. In addition, four texture features were found to be significant at the same time point, with an AUC of 0.69 for response prediction using the most significant feature for classification based on the pathological response. Our results suggest that texture analysis could provide clinicians with additional information to increase the accuracy of prediction of an individual response before NAC is started. PMID:24840393

  14. Enhancement of Odor-Induced Activity in the Canine Brain by Zinc Nanoparticles: A Functional MRI Study in Fully Unrestrained Conscious Dogs.

    PubMed

    Jia, Hao; Pustovyy, Oleg M; Wang, Yun; Waggoner, Paul; Beyers, Ronald J; Schumacher, John; Wildey, Chester; Morrison, Edward; Salibi, Nouha; Denney, Thomas S; Vodyanoy, Vitaly J; Deshpande, Gopikrishna

    2016-01-01

    Using noninvasive in vivo functional magnetic resonance imaging (fMRI), we demonstrate that the enhancement of odorant response of olfactory receptor neurons by zinc nanoparticles leads to increase in activity in olfaction-related and higher order areas of the dog brain. To study conscious dogs, we employed behavioral training and optical motion tracking for reducing head motion artifacts. We obtained brain activation maps from dogs in both anesthetized state and fully conscious and unrestrained state. The enhancement effect of zinc nanoparticles was higher in conscious dogs with more activation in higher order areas as compared with anesthetized dogs. In conscious dogs, voxels in the olfactory bulb and hippocampus showed higher activity to odorants mixed with zinc nanoparticles as compared with pure odorants, odorants mixed with gold nanoparticles as well as zinc nanoparticles alone. These regions have been implicated in odor intensity processing in other species including humans. If the enhancement effect of zinc nanoparticles observed in vivo are confirmed by future behavioral studies, zinc nanoparticles may provide a way for enhancing the olfactory sensitivity of canines for detection of target substances such as explosives and contraband substances at very low concentrations, which would otherwise go undetected. PMID:26464498

  15. Evidence of Key Tinnitus-Related Brain Regions Documented by a Unique Combination of Manganese-Enhanced MRI and Acoustic Startle Reflex Testing

    PubMed Central

    Holt, Avril Genene; Bissig, David; Mirza, Najab; Rajah, Gary; Berkowitz, Bruce

    2010-01-01

    Animal models continue to improve our understanding of tinnitus pathogenesis and aid in development of new treatments. However, there are no diagnostic biomarkers for tinnitus-related pathophysiology for use in awake, freely moving animals. To address this disparity, two complementary methods were combined to examine reliable tinnitus models (rats repeatedly administered salicylate or exposed to a single noise event): inhibition of acoustic startle and manganese-enhanced MRI. Salicylate-induced tinnitus resulted in wide spread supernormal manganese uptake compared to noise-induced tinnitus. Neither model demonstrated significant differences in the auditory cortex. Only in the dorsal cortex of the inferior colliculus (DCIC) did both models exhibit supernormal uptake. Therefore, abnormal membrane depolarization in the DCIC appears to be important in tinnitus-mediated activity. Our results provide the foundation for future studies correlating the severity and longevity of tinnitus with hearing loss and neuronal activity in specific brain regions and tools for evaluating treatment efficacy across paradigms. PMID:21179508

  16. Evidence of key tinnitus-related brain regions documented by a unique combination of manganese-enhanced MRI and acoustic startle reflex testing.

    PubMed

    Holt, Avril Genene; Bissig, David; Mirza, Najab; Rajah, Gary; Berkowitz, Bruce

    2010-01-01

    Animal models continue to improve our understanding of tinnitus pathogenesis and aid in development of new treatments. However, there are no diagnostic biomarkers for tinnitus-related pathophysiology for use in awake, freely moving animals. To address this disparity, two complementary methods were combined to examine reliable tinnitus models (rats repeatedly administered salicylate or exposed to a single noise event): inhibition of acoustic startle and manganese-enhanced MRI. Salicylate-induced tinnitus resulted in wide spread supernormal manganese uptake compared to noise-induced tinnitus. Neither model demonstrated significant differences in the auditory cortex. Only in the dorsal cortex of the inferior colliculus (DCIC) did both models exhibit supernormal uptake. Therefore, abnormal membrane depolarization in the DCIC appears to be important in tinnitus-mediated activity. Our results provide the foundation for future studies correlating the severity and longevity of tinnitus with hearing loss and neuronal activity in specific brain regions and tools for evaluating treatment efficacy across paradigms. PMID:21179508

  17. Laser-induced thermotherapy (LITT) for the treatment of liver metastases: the correlation of Gd-DTPA-enhanced magnetic resonance imaging (MRI) and histomorphological findings in the chronic model

    NASA Astrophysics Data System (ADS)

    Isbert, Christoph M.; Germer, Christoph-Thomas; Albrecht, Dirk; Schilling, Andreas; Heiniche, Antje; Roggan, Andre; Wolf, Karl J.; Mueller, Gerhard J.; Buhr, Heinz-Johannes

    1997-05-01

    The purpose of the study was to evaluate Gd-DTPA-enhanced MRI for the follow-up of laser-induced thermotherapy (LITT) in the treatment of liver metastases. Interstitial laser-induced thermotherapy (LITT) was performed in 55 chinchilla bastard rabbits with a Nd:YAG laser and a specially developed diffuser tip applicator. The animals were examined at different times using MRI and histological methods. T1-weighted spin-echo sequences were made with gadolinium-DTPA and submitted to correlation analysis. The analysis yielded a good correlation (r equals 0.96) between the largest lesion diameters. Lesions showed discontinuous regeneration kinetics with a 41% volume reduction 1 month after LITT. MRI of the lesion directly after LITT showed a hyperintense transition zone. Following the application of intravenous contrast medium, transition zone enhancement was first seen 72 - 96 hours after LITT. Even after 6 months, the laser-induced lesion is visualized as a non-enhanced area. Lesion regeneration followed the principles of wound healing. It is concluded that gadolinium-DTPA- enhanced MRI yielded definitive criteria for the follow-up assessment of LITT.

  18. Validation of 10-Minute Delayed Hepatocyte Phase Imaging with 30° Flip Angle in Gadoxetic Acid-Enhanced MRI for the Detection of Liver Metastasis

    PubMed Central

    Lee, Dahye; Cho, Eun-Suk; Kim, Dae Jung; Kim, Joo Hee; Yu, Jeong-Sik; Chung, Jae-Joon

    2015-01-01

    Objectives To compare 10-minute delayed hepatocyte phase imaging using a 30° flip angle (10min-FA30) and 20-minute hepatocyte phase imaging using a 10° FA (20min-FA10) in gadoxetic acid-enhanced MRI of patients with possible liver metastases, regarding lesion-to-liver contrast-to-noise ratio (CNR) and focal hepatic lesion (FHL) detection to evaluate whether 10min-FA30 would be superior to 20min-FA10. Materials and Methods Eighty-three patients with 248 liver metastases and 78 benign FHLs who underwent gadoxetic acid-enhanced MRI with 10min-FA30 and 20min-FA10 were enrolled. Lesion-to-liver CNRs were compared between the two image groups. Two radiologists independently assessed the presence of FHLs using a four-point scale and detection sensitivity was calculated. Results The mean CNR for liver metastases on the 10min-FA30 (248.5 ± 101.6) were significantly higher than that of the 20min-FA10 (187.4 ± 77.4) (p < 0.001). The mean CNR difference between the two image groups was 61.2 ± 56.8. There was no significant difference in detection sensitivity of FHLs for two readers between 10min-FA30 (mean 97.7%) and 20min-FA10 (mean 97.9%), irrespective of the lesion size or malignancy. Conclusion 10min-FA30 yielded higher CNR with similar sensitivity compared to 20min-FA10. This finding indicates that 10min-FA30 can potentially replace 20min-FA10 with higher diagnostic performance and save 10 minutes of time. PMID:26444677

  19. Heart MRI

    MedlinePLUS

    ... pictures of the heart. It does not use radiation (x-rays). Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of images. The test may be done as part of a chest MRI .

  20. Repeat Targeted Prostate Biopsy under Guidance of Multiparametric MRI-Correlated Real-Time Contrast-Enhanced Ultrasound for Patients with Previous Negative Biopsy and Elevated Prostate-Specific Antigen: A Prospective Study

    PubMed Central

    Jang, Dong Ryul; Jung, Dae Chul; Oh, Young Taik; Noh, Songmi; Han, Kyunghwa; Kim, Kiwook; Rha, Koon-Ho; Choi, Young Deuk; Hong, Sung Joon

    2015-01-01

    Objectives To prospectively determine whether multi-parametric MRI (mpMRI) - contrast-enhanced ultrasound (CEUS) correlated, imaging-guided target biopsy (TB) method could improve the detection of prostate cancer in re-biopsy setting of patients with prior negative biopsy. Methods From 2012 to 2014, a total of 42 Korean men with a negative result from previous systematic biopsy (SB) and elevated prostate-specific antigen underwent 3T mpMRI and real-time CEUS guided TB. Target lesions were determined by fusion of mpMRI and CEUS. Subsequently, 12-core SB was performed by a different radiologist. We compared core-based cancer detection rates (CaDR) using the generalized linear mixed model (GLIMMIX) for each biopsy method. Results Core-based CaDR was higher in TB (17.92%, 38 of 212 cores) than in SB (6.15%, 31 of 504 cores) (p < 0.0001; GLIMMIX). In the cancer-positive TB cores, CaDR with suspicious lesions by mpMRI was higher than that by CEUS (86.8% vs. 60.5%, p= 0.02; paired t-test) and concordant rate between mpMRI and CEUS was significantly different with discordant rate (48% vs. 52%, p=0.04; McNemar’s test). Conclusion The mpMRI-CEUS correlated TB technique for the repeat prostate biopsy of patients with prior negative biopsy can improve CaDR based on the number of cores taken. PMID:26083348

  1. Characterizing tumor changes during neoadjuvant treatment of locally advanced breast cancer patients (LABC) using dynamic-enhanced magnetic resonance imaging (DE-MRI)

    NASA Astrophysics Data System (ADS)

    Craciunescu, Oana I.; Jones, Ellen L.; Blackwell, Kimberly L.; Wong, Terence Z.; Rosen, Eric L.; Vujaskovic, Zeljko; MacFall, James R.; Liotcheva, Vlayka; Lora-Michiels, Michael; Prosnitz, Leonard R.; Samulski, Thaddeus V.; Dewhirst, Mark W.

    2005-04-01

    At Duke University Medical Center, selective LABC patients were treated on a protocol using neoadjuvant Myocet/Paclitaxel (ChT) and HT. With the purpose of generating perfusion/permeability parametric maps and to use gadolinium (Gd) enhancement curves to score and predict response to neoadjuvant treatment, a study was designed to acquire 3 sets of DE-MRI images along the 4 cycles of combined ChT and HT. A T1-weighted three-dimensional fast gradient echo technique was used over 30 minutes following bolus injection of Gd-based contrast agent. Perfusion/permeability maps were generated by fitting the signal intensity to a double exponential curve that generates washin (WiP) and washout (WoP), parameters that are associated with the tumors vascularity/permeability and cellularity. Based on the values of the WiP, the tumors were divided in lowWI (WiP < 100), mediumWI (100 200). During the HT treatments temperatures in the breast were measured invasively via a catheter inserted under CT guidance. Although minimum sampled temperatures give a crude indication of the temperature distribution, several thermal dose metrics were calculated for each of the HT fractions (e.g. T90, T50, T10). As expected, tumors that were more vascularized (i.e. higher WiP) heated less than tumors with low WiP, a degree on average. The adjuvant treatment also changed the shape and inhomogeneity of the perfusion/permeability maps, with dramatic changes after the first fraction in responders. The correlation between the thermal metrics and pathological response will be discussed, as well as possible correlation with other tumor physiology parameters. In conclusion, the Gd-enhancement analysis of DE-MRI images is able to generate information related to the tumor vascularity, permeability and cellularity that can correlate with the tumor's response to the neoadjuvant treatment in general, and to HT in particular. Work supported by a grant from the NCI CA42745.

  2. Combined Application of Gadoxetic Acid Disodium-Enhanced Magnetic Resonance Imaging (MRI) and Diffusion-Weighted Imaging (DWI) in the Diagnosis of Chronic Liver Disease-Induced Hepatocellular Carcinoma: A Meta-Analysis

    PubMed Central

    Li, Xiang; Li, Chenxia; Wang, Rong; Ren, Juan

    2015-01-01

    Objective Gadoxetic acid disodium (Gd-EOB-DTPA) is a magnetic resonance imaging (MRI) contrast agent to target the liver cells with normal function. In clinical practice, the Gd-EOB-DTPA produces high quality hepatocyte specific image 20 minutes after intravenous injection, so DWI sequence is often performed after the conventional dynamic scanning. However, there are still some disputes about whether DWI sequence will provide more effective diagnostic information in clinical practice. This study aimed to explore the diagnostic value of combining Gd-EOB-DTPA-enhanced MRI and DWI in the detection of hepatocellular carcinoma (HCC) in patients with chronic liver disease. Methods A systematic literature search was performed in the PubMed and Cochrane library database up to March 2015. The quality assessment of diagnostic accuracy studies (QUADAS) was used to evaluate the quality of studies. Heterogeneous test on the included literature was performed by using the software Review Manager 5.3. The MetaDiSc 1.4 software was used to calculate the pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio; meanwhile the summary receiver operating characteristics (SROC) curve was drawn to compare the diagnostic performance. Results A total of 13 literatures were included in this study. In 8 literatures regarding HCC diagnosis based on Gd-EOB-DTPA-enhanced MRI, the pooled sensitivity: 0.90 (95% confidence interval (CI): 0.88–0.93); specificity: 0.89 (95% CI: 0.85–0.92); positive likelihood ratio: 8.60 (95% CI: 6.20–11.92); negative likelihood ratio: 0.10 (95% CI: 0.08–0.14) were obtained. The area under curve (AUC) and Q values were 0.96 and 0.90, respectively. In 5 literatures relating to HCC diagnosis by combination of Gd-EOB-DTPA-enhanced MRI and DWI sequence, the pooled sensitivity: 0.88 (95% CI: 0.85–0.91), specificity: 0.96 (0.94–0.97), positive likelihood ratio: 19.63 (12.77–30.16), negative likelihood ratio: 0.10 (0.07–0.14) were obtained. The AUC value was 0.9833 and Q value was 0.9436. The AUC value of comprehensive evaluation method was significantly higher than that of Gd-EOB-DTPA-enhanced MRI alone(P<0.05). Conclusion Combination of Gd-EOB-DTPA-enhanced MRI and DWI sequence significantly improves in both the diagnostic accuracy and specificity of chronic liver disease-associated HCC. PMID:26629904

  3. Integration of DCE-MRI and DW-MRI Quantitative Parameters for Breast Lesion Classification

    PubMed Central

    Fusco, Roberta; Sansone, Mario; Filice, Salvatore; Granata, Vincenza; Catalano, Orlando; Amato, Daniela Maria; Di Bonito, Maurizio; D'Aiuto, Massimiliano; Capasso, Immacolata; Rinaldo, Massimo; Petrillo, Antonella

    2015-01-01

    Objective. The purpose of our study was to evaluate the diagnostic value of an imaging protocol combining dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DW-MRI) in patients with suspicious breast lesions. Materials and Methods. A total of 31 breast lesions (15 malignant and 16 benign proved by histological examination) in 26 female patients were included in this study. For both DCE-MRI and DW-MRI model free and model based parameters were computed pixel by pixel on manually segmented ROIs. Statistical procedures included conventional linear analysis and more advanced techniques for classification of lesions in benign and malignant. Results. Our findings indicated no strong correlation between DCE-MRI and DW-MRI parameters. Results of classification analysis show that combining of DCE parameters or DW-MRI parameter, in comparison of single feature, does not yield a dramatic improvement of sensitivity and specificity of the two techniques alone. The best performance was obtained considering a full combination of all features. Moreover, the classification results combining all features are dominated by DCE-MRI features alone. Conclusion. The combination of DWI and DCE-MRI does not show a potential to dramatically increase the sensitivity and specificity of breast MRI. DCE-MRI alone gave the same performance as in combination with DW-MRI. PMID:26339597

  4. Enhanced Antitumor Efficacy of a Vascular Disrupting Agent Combined with an Antiangiogenic in a Rat Liver Tumor Model Evaluated by Multiparametric MRI

    PubMed Central

    Chen, Feng; Feng, Yingmei; Zheng, Kaier; De Keyzer, Frederik; Li, Junjie; Feng, Yuanbo; Cona, Marlein Miranda; Wang, Huaijun; Jiang, Yansheng; Yu, Jie; Marchal, Guy; Verfaillie, Catherine; De Geest, Bart; Oyen, Raymond; Ni, Yicheng

    2012-01-01

    A key problem in solid tumor therapy is tumor regrowth from a residual viable rim after treatment with a vascular disrupting agent (VDA). As a potential solution, we studied a combined treatment of a VDA and antiangiogenic. This study was approved by the institutional ethical committee for the use and care of laboratory animals. Rats with implanted liver tumors were randomized into four treatment groups: 1) Zd6126 (Zd); 2) Thalidomide (Tha); 3) Zd in combination with Tha (ZdTha); and 4) controls. Multiparametric MRIs were performed and quantified before and after treatment. Circulating endothelial progenitor cells (EPCs) and plasma stromal cell-derived factor-1? (SDF-1?) were monitored. Tumor apoptosis, necrosis, and microvessels were verified by histopathology. A single use of Zd or Tha did not significantly delay tumor growth. The combined ZdTha showed enhanced antitumor efficacy due to synergistic effects; it induced a cumulative tumor apoptosis or necrosis, which resulted in significant delay in tumor growth and reduction in the viable tumor rim; it also reduced tumor vessel permeability; and it improved tumor hemodynamic indexes, most likely via a transient normalization of tumor vasculature induced by Tha. A stepwise linear regression analysis showed that the apparent diffusion coefficient was an independent predictor of tumor growth. We found no significant increases in Zd-induced circulating EPCs or plasma SDF-1?. ZdTha showed improved therapeutic efficacy in solid tumors compared to either agent alone. The therapeutic effects were successfully tracked in vivo with multiparametric MRI. PMID:22815943

  5. MRI-detectable polymeric micelles incorporating platinum anticancer drugs enhance survival in an advanced hepatocellular carcinoma model

    PubMed Central

    Vinh, Nguyen Quoc; Naka, Shigeyuki; Cabral, Horacio; Murayama, Hiroyuki; Kaida, Sachiko; Kataoka, Kazunori; Morikawa, Shigehiro; Tani, Tohru

    2015-01-01

    Hepatocellular carcinoma (HCC) is one of the most intractable and lethal cancers; most cases are diagnosed at advanced stages with underlying liver dysfunction and are frequently resistant to conventional chemotherapy and radiotherapy. The development of tumor-targeting systems may improve treatment outcomes. Nanomedicine platforms are of particular interest for enhancing chemotherapeutic efficiency, and they include polymeric micelles, which enable targeting of multiple drugs to solid tumors, including imaging and therapeutic agents. This allows concurrent diagnosis, targeting strategy validation, and efficacy assessment. We used polymeric micelles containing the T1-weighted magnetic resonance imaging contrast agent gadolinium-diethylenetriaminpentaacetic acid (Gd-DTPA) and the parent complex of the anticancer drug oxaliplatin [(1,2-diaminocyclohexane)platinum(II) (DACHPt)] for simultaneous imaging and therapy in an orthotopic rat model of HCC. The Gd-DTPA/DACHPt-loaded micelles were injected into the hepatic artery, and magnetic resonance imaging performance and antitumor activity against HCC, as well as adverse drug reactions were assessed. After a single administration, the micelles achieved strong and specific tumor contrast enhancement, induced high levels of tumor apoptosis, and significantly suppressed tumor size and growth. Moreover, the micelles did not induce severe adverse reactions and significantly improved survival outcomes in comparison to oxaliplatin or saline controls. Our results suggest that Gd-DTPA/DACHPt-loaded micelles are a promising approach for effective diagnosis and treatment of advanced HCC. PMID:26203241

  6. Dynamic Contrast Enhanced MRI Detects Early Response to Adoptive NK Cellular Immunotherapy Targeting the NG2 Proteoglycan in a Rat Model of Glioblastoma

    PubMed Central

    Thuen, Marte; Gras Navarro, Andrea; Huuse, Else Marie; Thorsen, Frits; Poli, Aurelie; Zimmer, Jacques; Haraldseth, Olav; Lie, Stein Atle; Enger, Per Øyvind; Chekenya, Martha

    2014-01-01

    There are currently no established radiological parameters that predict response to immunotherapy. We hypothesised that multiparametric, longitudinal magnetic resonance imaging (MRI) of physiological parameters and pharmacokinetic models might detect early biological responses to immunotherapy for glioblastoma targeting NG2/CSPG4 with mAb9.2.27 combined with natural killer (NK) cells. Contrast enhanced conventional T1-weighted MRI at 7±1 and 17±2 days post-treatment failed to detect differences in tumour size between the treatment groups, whereas, follow-up scans at 3 months demonstrated diminished signal intensity and tumour volume in the surviving NK+mAb9.2.27 treated animals. Notably, interstitial volume fraction (ve), was significantly increased in the NK+mAb9.2.27 combination therapy group compared mAb9.2.27 and NK cell monotherapy groups (p?=?0.002 and p?=?0.017 respectively) in cohort 1 animals treated with 1 million NK cells. ve was reproducibly increased in the combination NK+mAb9.2.27 compared to NK cell monotherapy in cohort 2 treated with increased dose of 2 million NK cells (p<0.0001), indicating greater cell death induced by NK+mAb9.2.27 treatment. The interstitial volume fraction in the NK monotherapy group was significantly reduced compared to mAb9.2.27 monotherapy (p<0.0001) and untreated controls (p?=?0.014) in the cohort 2 animals. NK cells in monotherapy were unable to kill the U87MG cells that highly expressed class I human leucocyte antigens, and diminished stress ligands for activating receptors. A significant association between apparent diffusion coefficient (ADC) of water and ve in combination NK+mAb9.2.27 and NK monotherapy treated tumours was evident, where increased ADC corresponded to reduced ve in both cases. Collectively, these data support histological measures at end-stage demonstrating diminished tumour cell proliferation and pronounced apoptosis in the NK+mAb9.2.27 treated tumours compared to the other groups. In conclusion, ve was the most reliable radiological parameter for detecting response to intralesional NK cellular therapy. PMID:25268630

  7. Can silicene distinguish nucleobases?

    NASA Astrophysics Data System (ADS)

    Scheicher, Ralph Hendrik; Amorim, Rodrigo G.

    2014-03-01

    The third generation of DNA sequencing devices are on the drawing board of industry and solid-state devices appear to be most promising for this task. In view of the silicon-based semiconductor industry it is noteworthy that a 2D allotrope of silicon was recently discovered, silicene, which resembles graphene in certain aspects. Given the prevalence of proposals to utilize graphene for DNA sequencing, we therefore chose to investigate the hypothesis whether a solid-state device based on silicene (which might be more straightforward to integrate with existing semiconductor technology) could electrically distinguish the four nucleobases in DNA. For this purpose, we used ab initio calculations based on density functional theory combined with the non-equilibrium Green's function method to study the electronic transport properties of a silicene sheet interacting with the constituents of DNA. We will present a detailed study of the physisorption process of the nucleobases on top of silicene, as well as how the adsorbed nucleobases would appear in a scanning tunneling microscope (STM) image. The key result that we will discuss is how the zero-bias transmittance of pristine silicene is altered when a specific nucleobase is adsorbed on its surface.

  8. Portable MRI

    SciTech Connect

    Espy, Michelle A.

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  9. Efficient Hilbert transform-based alternative to Tofts physiological models for representing MRI dynamic contrast-enhanced images in computer-aided diagnosis of prostate cancer

    NASA Astrophysics Data System (ADS)

    Boehm, Kevin M.; Wang, Shijun; Burtt, Karen E.; Turkbey, Baris; Weisenthal, Samuel; Pinto, Peter; Choyke, Peter; Wood, Bradford J.; Petrick, Nicholas; Sahiner, Berkman; Summers, Ronald M.

    2015-03-01

    In computer-aided diagnosis (CAD) systems for prostate cancer, dynamic contrast enhanced (DCE) magnetic resonance imaging is useful for distinguishing cancerous and benign tissue. The Tofts physiological model is a commonly used representation of the DCE image data, but the parameters require extensive computation. Hence, we developed an alternative representation based on the Hilbert transform of the DCE images. The time maximum of the Hilbert transform, a binary metric of early enhancement, and a pre-DCE value was assigned to each voxel and appended to a standard feature set derived from T2-weighted images and apparent diffusion coefficient maps. A cohort of 40 patients was used for training the classifier, and 20 patients were used for testing. The AUC was calculated by pooling the voxel-wise prediction values and comparing with the ground truth. The resulting AUC of 0.92 (95% CI [0.87 0.97]) is not significantly different from an AUC calculated using Tofts physiological models of 0.92 (95% CI [0.87 0.97]), as validated by a Wilcoxon signed rank test on each patient's AUC (p = 0.19). The time required for calculation and feature extraction is 11.39 seconds (95% CI [10.95 11.82]) per patient using the Hilbert-based feature set, two orders of magnitude faster than the 1319 seconds (95% CI [1233 1404]) required for the Tofts parameter-based feature set (p<0.001). Hence, the features proposed herein appear useful for CAD systems integrated into clinical workflows where efficiency is important.

  10. HO-1 gene overexpression enhances the beneficial effects of superparamagnetic iron oxide labeled bone marrow stromal cells transplantation in swine hearts underwent ischemia/reperfusion: an MRI study.

    PubMed

    Jiang, Yibo; Chen, Lijuan; Tang, Yaoliang; Ma, Genshan; Shen, Chengxing; Qi, Chunmei; Zhu, Qi; Yao, Yuyu; Liu, Naifeng

    2010-05-01

    To determine the effect of intracoronary transfer of superparamagnetic iron oxide (SPIO) labeled heme oxygenase-1 (HO-1) overexpressed bone marrow stromal cells (BMSCs) in a porcine myocardial ischemia/reperfusion model. Cell apoptosis was assayed and supernatant cytokine concentrations were measured in BMSCs that underwent hypoxia/reoxygen in vitro. Female mini-swines that underwent 1 h LAD occlusion followed by 1 h reperfusion were randomly allocated to receive intracoronary saline (control), 1 x 10(7) SPIO-labeled BMSCs transfected with pcDNA3.1-Lacz plasmid (Lacz-BMSCs), pcDNA3.1-human HO-1 (HO-1-BMSCs), pcDNA3.1-hHO-1 pretreated with a HO inhibitor, tin protoporphyrin (SnPP, n = 10 each). MRI and postmortem histological analysis were made at 1 week or 3 months thereafter. Post hypoxia/reoxygen in vitro, apoptosis was significantly reduced, supernatant VEGF significantly increased while TNF-alpha and IL-6 significantly reduced in HO-1-BMSCs group compared with Lacz-BMSCs group (all p < 0.05). Myocardial expression of VEGF was significantly higher in HO-1-BMSCs than in Lacz-BMSCs group at 1 week post transplantation (all p < 0.05). Signal voids induced by the SPIO were detected in the peri-infarction region in all BMSC groups at 1 week but not at 3 months post transplantation and the extent of the hypointense signal was the highest in HO-1-BMSCs group, and histological analysis showed that signal voids represented cardiac macrophages that engulfed the SPIO-labeled BMSCs. Pretreatment with SnPP significantly attenuated the beneficial effects of HO-1-BMSCs. Transplantation of HO-1-overexpressed BMSCs significantly enhanced the beneficial effects of BMSCs on improving cardiac function in this model. PMID:20033189

  11. 2015 Spring : Distinguished Honors As of: Jun 12, 2015

    E-print Network

    Kunkle, Tom

    _NAME HONORS Abdin Heba Abdel Distinguished Adams Daniel Brae Distinguished Adams Sydney Elaine Distinguished Brenner Alexis Hanna Distinguished Bridges Amanda LeAnne Distinguished Brown Addison Emily Distinguished

  12. Distinguishing modified gravity models

    NASA Astrophysics Data System (ADS)

    Brax, Philippe; Davis, Anne-Christine

    2015-10-01

    Modified gravity models with screening in local environments appear in three different guises: chameleon, K-mouflage and Vainshtein mechanisms. We propose to look for differences between these classes of models by considering cosmological observations at low redshift. In particular, we analyse the redshift dependence of the fine structure constant and the proton to electron mass ratio in each of these scenarios. When the absorption lines belong to unscreened regions of space such as dwarf galaxies, a time variation would be present for chameleons. For both K-mouflage and Vainshtein mechanisms, the cosmological time variation of the scalar field is not suppressed in both unscreened and screened environments, therefore enhancing the variation of constants and their detection prospect. We also consider the time variation of the redshift of distant objects using their spectrocopic velocities. We find that models of the K-mouflage and Vainshtein types have very different spectroscopic velocities as a function of redshift and that their differences with the ?-CDM template should be within reach of the future ELT-HIRES observations.

  13. FDG-PET SUV can distinguish between spinal sarcoidosis and myelopathy with canal stenosis.

    PubMed

    Sakushima, Ken; Yabe, Ichiro; Shiga, Tohru; Yashima-Yamada, Moemi; Tsuji-Akimoto, Sachiko; Terae, Satoshi; Sasaki, Hidenao

    2011-02-01

    Spinal cord sarcoidosis is a rare manifestation of sarcoidosis. Magnetic resonance imaging (MRI) of spinal cord sarcoidosis sometimes resembles that of the non-inflammatory spinal cord lesion. (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is an effective method to detect both systemic and central nervous system lesions in sarcoidosis. This study compared the standard uptake value (SUV) of FDG-PET between spinal cord sarcoidosis and non-inflammatory spinal cord lesions. We retrospectively reviewed the records of patients who underwent both spinal MRI and FDG-PET scans. We used SUV to evaluate the FDG-PET uptake of the lesion. The region of interest was the center of high-intensity areas on T2-weighted MR images. We included three patients with spinal cord sarcoidosis, five with myelomalacia caused by cervical spondylosis or ossification of the posterior longitudinal ligament, one with spinal cord edema associated with cervical spondylosis, and one with spinal cord edema associated with dural arteriovenous fistula. The spinal cord sarcoidosis group had a significantly higher SUV (mean 4.38, range 3.30-4.93) than patients with the other diseases (mean 1.87, range 1.42-2.74). The SUV of FDG-PET thus may be able to distinguish spinal cord sarcoidosis from other non-inflammatory lesions. FDG-PET can play an important role in the diagnosis of spinal cord sarcoidosis because the gadolinium enhancement in MRI is sometimes seen in spondylotic myelopathy or vascular malformation. FDG-PET is informative for the accurate diagnosis of spinal cord sarcoidosis and may enable clinicians to start treatment at an earlier stage. PMID:20820799

  14. Distinguishing features of ?-proteobacterial genomes

    PubMed Central

    Karlin, Samuel; Brocchieri, Luciano; Mrázek, Jan; Kaiser, Dale

    2006-01-01

    We analyzed several features of five currently available ?-proteobacterial genomes, including two aerobic bacteria exhibiting predatory behavior and three anaerobic sulfate-reducing bacteria. The ? genomes are distinguished from other bacteria by several properties: (i) The ? genomes contain two “giant” S1 ribosomal protein genes in contrast to all other bacterial types, which encode a single or no S1; (ii) in most ?-proteobacterial genomes the major ribosomal protein (RP) gene cluster is near the replication terminus whereas most bacterial genomes place the major RP cluster near the origin of replication; (iii) the ? genomes possess the rare combination of discriminating asparaginyl and glutaminyl tRNA synthetase (AARS) together with the amido-transferase complex (Gat CAB) genes that modify Asp-tRNAAsn into Asn-tRNAAsn and Glu-tRNAGln into Gln-tRNAGln; (iv) the TonB receptors and ferric siderophore receptors that facilitate uptake and removal of complex metals are common among ? genomes; (v) the anaerobic ? genomes encode multiple copies of the anaerobic detoxification protein rubrerythrin that can neutralize hydrogen peroxide; and (vi) ?54 activators play a more important role in the ? genomes than in other bacteria. ? genomes have a plethora of enhancer binding proteins that respond to environmental and intracellular cues, often as part of two-component systems; (vii) ? genomes encode multiple copies of metallo-?-lactamase enzymes; (viii) a host of secretion proteins emphasizing SecA, SecB, and SecY may be especially useful in the predatory activities of Myxococcus xanthus; (ix) ? proteobacteria drive many multiprotein machines in their periplasms and outer membrane, including chaperone-feeding machines, jets for slime secretion, and type IV pili. Bdellovibrio replicates in the periplasm of prey cells. The sulfate-reducing ? proteobacteria metabolize hydrogen and generate a proton gradient by electron transport. The predicted highly expressed genes from ? genomes reflect their different ecologies, metabolic strategies, and adaptations. PMID:16844781

  15. In vivo transport of Gd-DTPA2- into human meniscus and cartilage assessed with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC)

    PubMed Central

    2014-01-01

    Background Impaired stability is a risk factor in knee osteoarthritis (OA), where the whole joint and not only the joint cartilage is affected. The meniscus provides joint stability and is involved in the early pathological progress of OA. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been used to identify pre-radiographic changes in the cartilage in OA, but has been used less commonly to examine the meniscus, and then using only a double dose of the contrast agent. The purpose of this study was to enable improved early OA diagnosis by investigate the temporal contrast agent distribution in the meniscus and femoral cartilage simultaneously, in healthy volunteers, using 3D dGEMRIC at two different doses of the contrast agent Gd-DTPA2-. Methods The right knee in 12 asymptomatic volunteers was examined using a 3D Look-Locker sequence on two occasions after an intravenous injection of a double or triple dose of Gd-DTPA2- (0.2 or 0.3 mmol/kg body weight). The relaxation time (T1) and relaxation rate (R1?=?1/T1) were measured in the meniscus and femoral cartilage before, and 60, 90, 120 and 180 minutes after injection, and the change in relaxation rate (?R1) was calculated. Paired t-test and Analysis of Variance (ANOVA) were used for statistical evaluation. Results The triple dose yielded higher concentrations of Gd-DTPA2- in the meniscus and cartilage than the double dose, but provided no additional information. The observed patterns of ?R1 were similar for double and triple doses of the contrast agent. ?R1 was higher in the meniscus than in femoral cartilage in the corresponding compartments at all time points after injection. ?R1 increased until 90-180 minutes in both the cartilage and the meniscus (p?

  16. Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) Shows No Change in Cartilage Structural Composition after Viscosupplementation in Patients with Early-Stage Knee Osteoarthritis

    PubMed Central

    van Tiel, Jasper; Reijman, Max; Bos, Pieter K.; Hermans, Job; van Buul, Gerben M.; Bron, Esther E.; Klein, Stefan; Verhaar, Jan A. N.; Krestin, Gabriel P.; Bierma-Zeinstra, Sita M. A.; Weinans, Harrie; Kotek, Gyula; Oei, Edwin H. G.

    2013-01-01

    Introduction Viscosupplementation with hyaluronic acid (HA) of osteoarthritic (OA) knee joints has a well-established positive effect on clinical symptoms. This effect, however, is only temporary and the working mechanism of HA injections is not clear. It was suggested that HA might have disease modifying properties because of its beneficial effect on cartilage sulphated glycosaminoglycan (sGAG) content. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a highly reproducible, non-invasive surrogate measure for sGAG content and hence composition of cartilage. The aim of this study was to assess whether improvement in cartilage structural composition is detected using dGEMRIC 14 weeks after 3 weekly injections with HA in patients with early-stage knee OA. Methods In 20 early-stage knee OA patients (KLG I-II), 3D dGEMRIC at 3T was acquired before and 14 weeks after 3 weekly injections with HA. To evaluate patient symptoms, the knee injury and osteoarthritis outcome score (KOOS) and a numeric rating scale (NRS) for pain were recorded. To evaluate cartilage composition, six cartilage regions in the knee were analyzed on dGEMRIC. Outcomes of dGEMRIC, KOOS and NRS before and after HA were compared using paired t-testing. Since we performed multiple t-tests, we applied a Bonferroni-Holm correction to determine statistical significance for these analyses. Results All KOOS subscales (‘pain’, ‘symptoms’, ‘daily activities’, ‘sports’ and ’quality of life’) and the NRS pain improved significantly 14 weeks after Viscosupplementation with HA. Outcomes of dGEMRIC did not change significantly after HA compared to baseline in any of the cartilage regions analyzed in the knee. Conclusions Our results confirm previous findings reported in the literature, showing persisting improvement in symptomatic outcome measures in early-stage knee OA patients 14 weeks after Viscosupplementation. Outcomes of dGEMRIC, however, did not change after Viscosupplementation, indicating no change in cartilage structural composition as an explanation for the improvement of clinical symptoms. PMID:24223194

  17. Dynamic contrast-enhanced MRI in mouse tumors at 11.7 T: comparison of three contrast agents with different molecular weights to assess the early effects of combretastatin A4.

    PubMed

    Fruytier, A-C; Magat, J; Neveu, M-A; Karroum, O; Bouzin, C; Feron, O; Jordan, B; Cron, G O; Gallez, B

    2014-11-01

    Dynamic contrast-enhanced (DCE)-MRI is useful to assess the early effects of drugs acting on tumor vasculature, namely anti-angiogenic and vascular disrupting agents. Ultra-high-field MRI allows higher-resolution scanning for DCE-MRI while maintaining an adequate signal-to-noise ratio. However, increases in susceptibility effects, combined with decreases in longitudinal relaxivity of gadolinium-based contrast agents (GdCAs), make DCE-MRI more challenging at high field. The aim of this work was to explore the feasibility of using DCE-MRI at 11.7 T to assess the tumor hemodynamics of mice. Three GdCAs possessing different molecular weights (gadoterate: 560 Da, 0.29 mmol Gd/kg; p846: 3.5 kDa, 0.10 mmol Gd/kg; and p792: 6.47 kDa, 0.15 mmol Gd/kg) were compared to see the influence of the molecular weight in the highlight of the biologic effects induced by combretastatin A4 (CA4). Mice bearing transplantable liver tumor (TLT) hepatocarcinoma were divided into two groups (n = 5-6 per group and per GdCA): a treated group receiving 100 mg/kg CA4, and a control group receiving vehicle. The mice were imaged at 11.7 T with a T1 -weighted FLASH sequence 2 h after the treatment. Individual arterial input functions (AIFs) were computed using phase imaging. These AIFs were used in the Extended Tofts Model to determine K(trans) and vp values. A separate immunohistochemistry study was performed to assess the vascular perfusion and the vascular density. Phase imaging was used successfully to measure the AIF for the three GdCAs. In control groups, an inverse relationship between the molecular weight of the GdCA and K(trans) and vp values was observed. K(trans) was significantly decreased in the treated group compared with the control group for each GdCA. DCE-MRI at 11.7 T is feasible to assess tumor hemodynamics in mice. With K(trans) , the three GdCAs were able to track the early vascular effects induced by CA4 treatment. PMID:25323069

  18. Tumor Metabolism and Perfusion in Head and Neck Squamous Cell Carcinoma: Pretreatment Multimodality Imaging With {sup 1}H Magnetic Resonance Spectroscopy, Dynamic Contrast-Enhanced MRI, and [{sup 18}F]FDG-PET

    SciTech Connect

    Jansen, Jacobus F.A.; Schoeder, Heiko; Lee, Nancy Y.; Stambuk, Hilda E.; Wang Ya; Fury, Matthew G.; Patel, Senehal G.; Pfister, David G.; Shah, Jatin P.; Koutcher, Jason A.; Shukla-Dave, Amita

    2012-01-01

    Purpose: To correlate proton magnetic resonance spectroscopy ({sup 1}H-MRS), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and {sup 18}F-labeled fluorodeoxyglucose positron emission tomography ([{sup 18}F]FDG PET) of nodal metastases in patients with head and neck squamous cell carcinoma (HNSCC) for assessment of tumor biology. Additionally, pretreatment multimodality imaging was evaluated for its efficacy in predicting short-term response to treatment. Methods and Materials: Metastatic neck nodes were imaged with {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET in 16 patients with newly diagnosed HNSCC, before treatment. Short-term patient radiological response was evaluated at 3 to 4 months. Correlations among {sup 1}H-MRS (choline concentration relative to water [Cho/W]), DCE-MRI (volume transfer constant [K{sup trans}]; volume fraction of the extravascular extracellular space [v{sub e}]; and redistribution rate constant [k{sub ep}]), and [{sup 18}F]FDG PET (standard uptake value [SUV] and total lesion glycolysis [TLG]) were calculated using nonparametric Spearman rank correlation. To predict short-term responses, logistic regression analysis was performed. Results: A significant positive correlation was found between Cho/W and TLG ({rho} = 0.599; p = 0.031). Cho/W correlated negatively with heterogeneity measures of standard deviation std(v{sub e}) ({rho} = -0.691; p = 0.004) and std(k{sub ep}) ({rho} = -0.704; p = 0.003). Maximum SUV (SUVmax) values correlated strongly with MRI tumor volume ({rho} = 0.643; p = 0.007). Logistic regression indicated that std(K{sup trans}) and SUVmean were significant predictors of short-term response (p < 0.07). Conclusion: Pretreatment multimodality imaging using {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET is feasible in HNSCC patients with nodal metastases. Additionally, combined DCE-MRI and [{sup 18}F]FDG PET parameters were predictive of short-term response to treatment.

  19. Multivoxel 1H MR spectroscopy is superior to contrast-enhanced MRI for response assessment after anti-angiogenic treatment of orthotopic human glioma xenografts and provides handles for metabolic targeting

    PubMed Central

    Hamans, Bob; Navis, Anna Catharina; Wright, Alan; Wesseling, Pieter; Heerschap, Arend; Leenders, William

    2013-01-01

    Background Anti-angiogenic treatment of glioblastoma characteristically results in therapy resistance and tumor progression via diffuse infiltration. Monitoring tumor progression in these patients is thwarted because therapy results in tumor invisibility in contrast-enhanced (CE) MRI. To address this problem, we examined whether tumor progression could be monitored by metabolic mapping using 1H MR spectroscopic imaging (MRSI). Methods We treated groups of BALB/c nu/nu mice carrying different orthotopic diffuse-infiltrative glioblastoma xenografts with bevacizumab (anti–vascular endothelial growth factor [VEGF] antibody, n = 13), cabozantinib (combined VEGF receptor 2/c-Met tyrosine kinase inhibitor, n = 11), or placebo (n = 15) and compared CE-MRI with MRS-derived metabolic maps before, during, and after treatment. Metabolic maps and CE-MRIs were subsequently correlated to histology and immunohistochemistry. Results In vivo imaging of choline/n-acetyl aspartate ratios via multivoxel MRS is better able to evaluate response to therapy than CE-MRI. Lactate imaging revealed that diffuse infiltrative areas in glioblastoma xenografts did not present with excessive glycolysis. In contrast, glycolysis was observed in hypoxic areas in angiogenesis-dependent compact regions of glioma only, especially after anti-angiogenic treatment. Conclusion Our data present MRSI as a powerful and feasible approach that is superior to CE-MRI and may provide handles for optimizing treatment of glioma. Furthermore, we show that glycolysis is more prominent in hypoxic areas than in areas of diffuse infiltrative growth. The Warburg hypothesis of persisting glycolysis in tumors under normoxic conditions may thus not be valid for diffuse glioma. PMID:24158109

  20. Play the MRI Game

    MedlinePLUS

    ... Teachers' Questionnaire MRI Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  1. Leg MRI scan

    MedlinePLUS

    ... imaging - leg; Magnetic resonance imaging - lower extremity; MRI - ankle; Magnetic resonance imaging - ankle; MRI - femur; MRI - leg ... or bone scan Birth defects of the leg, ankle, or foot Bone pain and fever Broken bone ...

  2. Computer-aided detection of brain tumor invasion using multiparametric MRI

    PubMed Central

    Jensen, Todd R.; Schmainda, Kathleen M.

    2010-01-01

    Purpose To determine the potential of using a computer-aided detection method to intelligently distinguish peritumoral edema alone from peritumor edema consisting of tumor using a combination of high-resolution morphological and physiological magnetic resonance imaging (MRI) techniques available on most clinical MRI scanners. Materials and Methods This retrospective study consisted of patients with two types of primary brain tumors: meningiomas (n=7) and glioblastomas (n=11). Meningiomas are typically benign and have a clear delineation of tumor and edema. Glioblastomas are known to invade outside the contrast-enhancing area. Four classifiers of differing designs were trained using morphological, diffusion-weighted, and perfusion-weighted features derived from MRI to discriminate tumor and edema, tested on edematous regions surrounding tumors, and assessed for their ability to detect nonenhancing tumor invasion. Results The four classifiers provided similar measures of accuracy when applied to the training and testing data. Each classifier was able to identify areas of non-enhancing tumor invasion supported with adjunct images or follow-up studies. Conclusion The combination of features derived from morphological and physiological imaging techniques contains the information necessary for computer-aided detection of tumor invasion and allows for the identification of tumor invasion not previously visualized on morphological, diffusion-weighted, and perfusion-weighted images and maps. Further validation of this approach requires obtaining spatially co-registered tissue samples in a study with a larger sample size. PMID:19711398

  3. 2015 Spring : Highly Distinguished Honors As of: Jun 12, 2015

    E-print Network

    Kunkle, Tom

    Alba Highly Distinguished Banks Annsley Elizabeth Highly Distinguished Banks Kendall Nicole Highly Distinguished Barth Lara Katharina Highly Distinguished Bartholomew Zak Henry Highly Distinguished Barton Julie

  4. Environmentally responsive MRI contrast agents

    PubMed Central

    Davies, Gemma-Louise; Kramberger, Iris; Davis, Jason J.

    2015-01-01

    Biomedical imaging techniques can provide a vast amount of anatomical information, enabling diagnosis and the monitoring of disease and treatment profile. MRI uniquely offers convenient, non-invasive, high resolution tomographic imaging. A considerable amount of effort has been invested, across several decades, in the design of non toxic paramagnetic contrast agents capable of enhancing positive MRI signal contrast. Recently, focus has shifted towards the development of agents capable of specifically reporting on their local biochemical environment, where a switch in image contrast is triggered by a specific stimulus/biochemical variable. Such an ability would not only strengthen diagnosis but also provide unique disease-specific biochemical insight. This feature article focuses on recent progress in the development of MRI contrast switching with molecular, macromolecular and nanoparticle-based agents. PMID:24040650

  5. Feasibility of simultaneous whole-brain imaging on an integrated PET-MRI system using an enhanced 2-point Dixon attenuation correction method

    PubMed Central

    Anazodo, Udunna C.; Thiessen, Jonathan D.; Ssali, Tracy; Mandel, Jonathan; Günther, Matthias; Butler, John; Pavlosky, William; Prato, Frank S.; Thompson, R. Terry; St. Lawrence, Keith S.

    2015-01-01

    Purpose: To evaluate a potential approach for improved attenuation correction (AC) of PET in simultaneous PET and MRI brain imaging, a straightforward approach that adds bone information missing on Dixon AC was explored. Methods: Bone information derived from individual T1-weighted MRI data using segmentation tools in SPM8, were added to the standard Dixon AC map. Percent relative difference between PET reconstructed with Dixon+bone and with Dixon AC maps were compared across brain regions of 13 oncology patients. The clinical potential of the improved Dixon AC was investigated by comparing relative perfusion (rCBF) measured with arterial spin labeling to relative glucose uptake (rPETdxbone) measured simultaneously with 18F-flurodexoyglucose in several regions across the brain. Results: A gradual increase in PET signal from center to the edge of the brain was observed in PET reconstructed with Dixon+bone. A 5–20% reduction in regional PET signals were observed in data corrected with standard Dixon AC maps. These regional underestimations of PET were either reduced or removed when Dixon+bone AC was applied. The mean relative correlation coefficient between rCBF and rPETdxbone was r = 0.53 (p < 0.001). Marked regional variations in rCBF-to-rPET correlation were observed, with the highest associations in the caudate and cingulate and the lowest in limbic structures. All findings were well matched to observations from previous studies conducted with PET data reconstructed with computed tomography derived AC maps. Conclusion: Adding bone information derived from T1-weighted MRI to Dixon AC maps can improve underestimation of PET activity in hybrid PET-MRI neuroimaging. PMID:25601825

  6. Research Report Gamma Oscillations Distinguish

    E-print Network

    Sederberg, Per B.

    Research Report Gamma Oscillations Distinguish True From False Memories Per B. Sederberg,1 Andreas patients under- going treatment for epilepsy performed a verbal free- recall task. These analyses revealed, & Engel, 2000; Schacter & Wagner, 1999; Squire, 1992). A topic of great interest is whether neural

  7. High-temporospatial-resolution dynamic contrast-enhanced (DCE) wrist MRI with variable-density pseudo-random circular Cartesian undersampling (CIRCUS) acquisition: evaluation of perfusion in rheumatoid arthritis patients.

    PubMed

    Liu, Jing; Pedoia, Valentina; Heilmeier, Ursula; Ku, Eric; Su, Favian; Khanna, Sameer; Imboden, John; Graf, Jonathan; Link, Thomas; Li, Xiaojuan

    2016-01-01

    This study is to evaluate highly accelerated three-dimensional (3D) dynamic contrast-enhanced (DCE) wrist MRI for assessment of perfusion in rheumatoid arthritis (RA) patients. A pseudo-random variable-density undersampling strategy, circular Cartesian undersampling (CIRCUS), was combined with k-t SPARSE-SENSE reconstruction to achieve a highly accelerated 3D DCE wrist MRI. Two healthy volunteers and 10 RA patients were studied. Two patients were on methotrexate (MTX) only (Group I) and the other eight were treated with a combination therapy of MTX and anti-tumor necrosis factor (TNF) therapy (Group II). Patients were scanned at baseline and 3?month follow-up. DCE MR images were used to evaluate perfusion in synovitis and bone marrow edema pattern in the RA wrist joints. A series of perfusion parameters was derived and compared with clinical disease activity scores of 28 joints (DAS28). 3D DCE wrist MR images were obtained with a spatial resolution of 0.3?×?0.3?×?1.5?mm(3) and temporal resolution of 5?s (with an acceleration factor of 20). The derived perfusion parameters, most notably transition time (dT) of synovitis, showed significant negative correlations with DAS28-ESR (r?=?-0.80, p?MRI with improved temporospatial resolution has been achieved in RA patients and provides accurate assessment of neovascularization and perfusion in RA joints, showing promise as a potential tool for evaluating treatment responses. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26608949

  8. DistinguishedLectureSeries City University Distinguished Lecture Series

    E-print Network

    Po, Lai-Man

    @cityu.edu.hk Speaker Dr Lee Kai-fu Chairman and CEO of Innovation Works Betting on China's Innovations -- A Perspective from Innovation Works on Thursday, 3 December 2015 at 4:00 pm at Wei Hing Theatre 6/F Amenities.cityu.edu.hk/vprt/distinguished_lecture_series/upcoming.htm Biography Dr Lee Kai-fu is the Chairman and CEO of Innovation Works which was founded in September, 2009

  9. Intra voxel analysis in MRI

    NASA Astrophysics Data System (ADS)

    Ambrosanio, Michele; Baselice, Fabio; Ferraioli, Giampaolo; Pascazio, Vito

    2014-03-01

    A new application of Compressive Sensing (CS) in Magnetic Resonance Imaging (MRI) field is presented. In particular, first results of the Intra Voxel Analysis (IVA) technique are reported. The idea is to exploit CS peculiarities in order to distinguish different contributions inside the same resolution cell, instead of reconstructing images from not fully sampled k-space acquisition. Applied to MRI field, this means the possibility of estimating the presence of different tissues inside the same voxel, i.e. in one pixel of the obtained image. In other words, the method is the first attempt, as far as we know, of achieving Spectroscopy-like results starting from each pixel of MR images. In particular, tissues are distinguished each others by evaluating their spin-spin relaxation times. Within this manuscript, first results on clinical dataset, in particular a phantom made by aqueous solution and oil and an occipital brain lesion corresponding to a metastatic breast cancer nodule, are reported. Considering the phantom dataset, in particular focusing on the slice where the separation between water and oil occurs, the methodology is able to distinguish the two components with different spin-spin relaxation times. With respect to clinical dataset,focusing on a voxel of the lesion area, the approach is able to detect the presence of two tissues, namely the healthy and the cancer related ones, while in other location outside the lesion only the healthy tissue is detected. Of course, these are the first results of the proposed methodology, further studies on different types of clinical datasets are required in order to widely validate the approach. Although few datasets have been considered, results seem both interesting and promising.

  10. Stepwise heterogeneity analysis of breast tumors in perfusion DCE-MRI datasets

    NASA Astrophysics Data System (ADS)

    Mohajer, Mojgan; Schmid, Volker J.; Engels, Nina A.; Noel, Peter B.; Rummeny, Ernst; Englmeier, Karl-Hans

    2012-03-01

    The signal curves in perfusion dynamic contrast enhanced MRI (DCE-MRI) of cancerous breast tissue reveal valuable information about tumor angiogenesis. Pathological studies have illustrated that breast tumors consist of different subregions, especially with more homogeneous properties during their growth. Differences should be identifiable in DCEMRI signal curves if the characteristics of these sub-regions are related to the perfusion and angiogenesis. We introduce a stepwise clustering method which in a first step uses a new similarity measure. The new similarity measure (PM) compares how parallel washout phases of two curves are. To distinguish the starting point of the washout phase, a linear regression method is partially fitted to the curves. In the next step, the minimum signal value of the washout phase is normalized to zero. Finally, PM is calculated according to maximal variation among the point wise differences during washout phases. In the second step of clustering the groups of signal curves with parallel washout are clustered using Euclidean distance. The introduced method is evaluated on 15 DCE-MRI breast datasets with different types of breast tumors. The use of our new heterogeneity analysis is feasible in single patient examination and improves breast MR diagnostics.

  11. Identification of High-Risk Plaques by MRI and Fluorescence Imaging in a Rabbit Model of Atherothrombosis

    PubMed Central

    Hua, Ning; Baik, Fred; Pham, Tuan; Phinikaridou, Alkystis; Giordano, Nick; Friedman, Beth; Whitney, Michael; Nguyen, Quyen T.; Tsien, Roger Y.; Hamilton, James A.

    2015-01-01

    Introduction The detection of atherosclerotic plaques at risk for disruption will be greatly enhanced by molecular probes that target vessel wall biomarkers. Here, we test if fluorescently-labeled Activatable Cell Penetrating Peptides (ACPPs) could differentiate stable plaques from vulnerable plaques that disrupt, forming a luminal thrombus. Additionally, we test the efficacy of a combined ACPP and MRI technique for identifying plaques at high risk of rupture. Methods and Results In an atherothrombotic rabbit model, disrupted plaques were identified with in vivo MRI and co-registered in the same rabbit aorta with the in vivo uptake of ACPPs, cleaved by matrix metalloproteinases (MMPs) or thrombin. ACPP uptake, mapped ex vivo in whole aortas, was higher in disrupted compared to non-disrupted plaques. Specifically, disrupted plaques demonstrated a 4.5~5.0 fold increase in fluorescence enhancement, while non-disrupted plaques showed only a 2.2~2.5 fold signal increase. Receiver operating characteristic (ROC) analysis indicates that both ACPPs (MMP and thrombin) show high specificity (84.2% and 83.2%) and sensitivity (80.0% and 85.7%) in detecting disrupted plaques. The detection power of ACPPs was improved when combined with the MRI derived measure, outward remodeling ratio. Conclusions Our targeted fluorescence ACPP probes distinguished disrupted plaques from stable plaques with high sensitivity and specificity. The combination of anatomic, MRI-derived predictors for disruption and ACPP uptake can further improve the power for identification of high-risk plaques and suggests future development of ACPPs with molecular MRI as a readout. PMID:26448434

  12. Outcome Classification of Preschool Children with Autism Spectrum Disorders Using Mri Brain Measures.

    ERIC Educational Resources Information Center

    Akshoomoff, Natacha; Lord, Catherine; Lincoln, Alan J.; Courchesne, Rachel Y.; Carper, Ruth A.; Townsend, Jeanne; Courchesne, Eric

    2004-01-01

    Objective: To test the hypothesis that a combination of magnetic resonance imaging (MRI) brain measures obtained during early childhood distinguish children with autism spectrum disorders (ASD) from typically developing children and is associated with functional outcome. Method: Quantitative MRI technology was used to measure gray and white matter…

  13. Magnetic Resonance Imaging (MRI)

    MedlinePLUS

    ... Your Best Self Smart Snacking Losing Weight Safely Magnetic Resonance Imaging (MRI) KidsHealth > Teens > Cancer Center > Diagnostic Tests > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ...

  14. Sinus MRI scan

    MedlinePLUS

    MRI of the sinuses; Magnetic resonance imaging - sinuses; Maxillary sinus MRI ... Mosby; 2015:chap 41. Wilkinson ID, Graves MJ.. Magnetic resonance imaging: basic principles In: Adam A, Dixon AK, Gillard ...

  15. MRI (Magnetic Resonance Imaging)

    MedlinePLUS

    ... Radiation-Emitting Products and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More ... MB) Also available in Other Language versions . Description Magnetic resonance imaging (MRI) is a medical imaging procedure ...

  16. MRI in breast cancer therapy monitoring

    PubMed Central

    McLaughlin, Rebekah; Hylton, Nola

    2015-01-01

    Breast MRI has several roles in the clinical management of breast cancer, including as a screening method for high-risk women, as a diagnostic tool used as an adjunct to mammography and ultrasound, and for the staging of disease extent prior to treatment. In addition to these uses, MRI is also employed to track small changes in tumor size and microenvironment. MRI has produced several early indicators of treatment response in clinical trials over the last 10 years, including initial lesion pattern, changes in lesion size, kinetic parameters, apparent diffusion coefficient and T2 value; the related technique of 1H MRS has also shown that choline concentration, T2 value and water-to-fat ratio are response indicators. In addition to measuring anatomical changes in the lesion size, as performed in traditional radiology, MRI has the ability to track vascular and cellular changes using dynamic contrast-enhanced MRI and diffusion-weighted MRI, respectively. By adding 1H MRS to MRI examinations, metabolic changes can also be determined. These functional imaging techniques allow studies to focus on early time points relative to neoadjuvant treatment. Early treatment response predictors may allow therapy to be tailored to individual patients and thus aid in the realization of the goal of personalized medicine. PMID:21692116

  17. Primal 3D MRI

    E-print Network

    Kim, Panki

    ANATOMY.TV #12;- Primal 3D . 3D , , , , , , , MRI - , , , , - , , , , - , 3D Anatomy.TV #12;3D ATLAS #12;Home #12;3D ATLAS - 1 3D -Anatomy: 3D - MRI: MRI Anatomy - Slides: - Movies: #12;3D ATLAS - 2 Layers

  18. Alcoa Foundation Engineering Research Awards Distinguished = THE ALCOA FOUNDATION DISTINGUISHED ENGINEERING

    E-print Network

    Frey, H. Christopher

    and Biomolecular Engineering, Distinguished #12;David Kaber, Industrial and Systems Engineering, Achievement 2005 Engineering, Achievement 2001 Ruben Carbonell, Chemical Engineering, Distinguished Yuan-Shin Lee, Industrial and Computer Engineering, Distinguished Russell E. King, Industrial Engineering, Achievement 1994 Carol K. Hall

  19. Distinguishability of the symmetric states

    E-print Network

    M. A. Jafarizadeh; P. Sadeghi; d. Akhgar; P. Mahmoudi

    2015-03-20

    In this paper, the distinguishability of multipartite geometrically uniform quantum states obtained from a single reference state is studied in the symmetric subspace. We specially focus our attention on the unitary transformation in a way that the produced states remain in the symmetric subspace, so rotation group with Jy as the generator of rotation is applied. The optimal probability and measurements are obtained for the pure and some special mixed separable states and the results are compared with those obtained at the previous articles for the special cases. The results are valid for lin- early dependent states. The discrimination of these states is also investigated using the separable measurement. We introduce appropriate transformation to gain the optimal separable measurements equivalent to the optimal global measurements with the same optimal probability.

  20. White matter changes in Leber's hereditary optic neuropathy: MRI findings.

    PubMed

    Küker, W; Weir, A; Quaghebeur, G; Palace, J

    2007-05-01

    Leber's hereditary optic neuropathy is a mitochondrial disorder causing bilateral optic nerve degeneration. It is sometimes associated with clinical signs of multiple sclerosis. We report MRI findings in two patients with LHON-MS and comment on possible distinguishing features of this disease entity. PMID:17437624

  1. MRI Features of Hepatocellular Carcinoma Related to Biologic Behavior

    PubMed Central

    Cho, Eun-Suk

    2015-01-01

    Imaging studies including magnetic resonance imaging (MRI) play a crucial role in the diagnosis and staging of hepatocellular carcinoma (HCC). Several recent studies reveal a large number of MRI features related to the prognosis of HCC. In this review, we discuss various MRI features of HCC and their implications for the diagnosis and prognosis as imaging biomarkers. As a whole, the favorable MRI findings of HCC are small size, encapsulation, intralesional fat, high apparent diffusion coefficient (ADC) value, and smooth margins or hyperintensity on the hepatobiliary phase of gadoxetic acid-enhanced MRI. Unfavorable findings include large size, multifocality, low ADC value, non-smooth margins or hypointensity on hepatobiliary phase images. MRI findings are potential imaging biomarkers in patients with HCC. PMID:25995679

  2. A single dose of the serotonin neurotransmission agonist paroxetine enhances motor output: double-blind, placebo-controlled, fMRI study in healthy subjects.

    PubMed

    Loubinoux, Isabelle; Pariente, Jérémie; Boulanouar, Kader; Carel, Christophe; Manelfe, Claude; Rascol, Olivier; Celsis, Pierre; Chollet, François

    2002-01-01

    Since serotonin (5-HT) stimulates motor function, pharmacological potentiation of 5-HT neurotransmission may improve motor function in healthy subjects and, possibly, recovery in post-stroke patients. Indeed, fluoxetine, a selective serotonin reuptake inhibitor (SSRI), increased activation in executive motor areas of healthy subjects as fenozolone, a releaser of monoamines (including noradrenaline, dopamine, and serotonin) from intracellular stores. This study is intended to test the hypothesis that paroxetine can likewise modulate brain motor activity in a dose-dependent manner in healthy subjects. In a double-blind counterbalanced study, six subjects underwent functional MRI examinations on three sessions 1 week apart (E1, E2, and E3) at the time of peak plasma concentrations (5 h after drug intake, i.e., either 20 or 60 mg of paroxetine or placebo) with a complex sequential opposition task. Rest and activation alternated in a block design. During activation, subjects performed, with the right hand, a 1-Hz-paced task that alternated two fist closings with a sequential opposition task. Paroxetine elicited effects similar to those reported for fluoxetine; notable changes were hyperactivation in the contralateral S1/M1, and posterior SMA and widespread hypoactivation of basal ganglia and cerebellum. There was an inverse correlation between dose and effect: significantly greater effects were observed with the 20-mg dose compared with 60 mg. Paroxetine dose-dependently modulates activation of the entire motor pathway in a way that favors motor output. Thus, a single dose of the SSRI paroxetine reorganized motor processing. PMID:11771971

  3. Detectability of MRI Turbulence in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Teague, Richard; Semenov, Dmitry; Flock, Mario; Henning, Thomas

    2015-08-01

    Protoplanetary disks are the nurseries of planet formation. Within them, turbulence acts as a stirring mechanism, combining the large population of small grains successively into pebbles, planetesimals and eventually planetary cores. There are many tuburbulent mechanisms proposed to fulfil this role, however, current observations are not sufficient to distinguish one mechanism from the other.This poster looks at the hallmarks of magneto-rotational instabilities (MRI), which relies on the coupling of the gas to the magnetic fields of the disk. Previous attempts to determine the electron fraction necessary for MRI to be present are hampered by the lack of atomic ions observed in disks and a large uncertainty when scaling abundance molecualr ions which are readily observed.It has been shown with global-MHD models, however, that MRI turbulence can incite distinct azimuthal dependent strucutres in the gas of the disk. We explore the possibility of identifying this non-Keplerian nature of a disk's kinematical structure and discuss whether, through a mode analysis of the kinematic structure, one can isolate MRI tuburlence from other forms with full ALMA capabilities.

  4. Local and Global Distinguishability in Quantum Interferometry

    SciTech Connect

    Durkin, Gabriel A.; Dowling, Jonathan P.

    2007-08-17

    A statistical distinguishability based on relative entropy characterizes the fitness of quantum states for phase estimation. This criterion is employed in the context of a Mach-Zehnder interferometer and used to interpolate between two regimes of local and global phase distinguishability. The scaling of distinguishability in these regimes with photon number is explored for various quantum states. It emerges that local distinguishability is dependent on a discrepancy between quantum and classical rotational energy. Our analysis demonstrates that the Heisenberg limit is the true upper limit for local phase sensitivity. Only the ''NOON'' states share this bound, but other states exhibit a better trade-off when comparing local and global phase regimes.

  5. Novel approaches to imaging epilepsy by MRI

    PubMed Central

    Hetherington, Hoby

    2009-01-01

    As the concept of a network of injury has emerged in the treatment of epilepsy, the importance of evaluating that network noninvasively has also grown. Recently, studies utilizing magnetic resonance spectroscopic imaging, manganese-enhanced MRI and functional (f)MRI measures of resting state connectivity have demonstrated their ability to detect injury and dysfunction in cerebral networks involved in the propagation of seizures. The ability to noninvasively detect neuronal injury and dysfunction throughout cerebral networks should improve surgical planning, provide guidance for placement of devices that target network propagation and provide insights into the mechanisms of recurrence following resective surgery. PMID:20161076

  6. Characteristics of Distinguished Programs of Agricultural Education

    ERIC Educational Resources Information Center

    Birkenholz, Robert J.; Simonsen, Jon C.

    2011-01-01

    Academic program rankings are highly anticipated by many university administrators, faculty, and alumni. This study analyzed the perceptions of agricultural education departmental contact persons to identify esteemed post-secondary agricultural education programs and the distinguishing characteristics of each program. The ten most distinguished

  7. High field functional MRI.

    PubMed

    Di Salle, F; Esposito, F; Elefante, A; Scarabino, T; Volpicelli, A; Cirillo, S; Elefante, R; Seifritz, E

    2003-11-01

    Functional magnetic resonance imaging (fMRI) has become the most widely used approach for studying brain functions in humans. The rapid and widespread diffusion of fMRI has been favoured by the properties this technique presents, and particularly by its sensitivity in analysing brain functional phenomena and by the lack of biological invasiveness, resulting in an unprecedented and unparalleled flexibility of use. These properties of fMRI brought the functional examination of the brain within the reach of the whole neuroscience community and have appreciably stimulated the research on the functional processes of the living brain. Among the main features of fMRI, its spatial and temporal resolution represents clear advantages compared with the other methods of functional neuroimaging. In fact, the high spatial resolution of fMRI permits to produce more precise and better localised information, and its temporal resolution provides the potential of a better understanding of neural dynamics at the level of single functional areas and of the neural constituents of functional patterns. A fundamental possibility of improving spatial and temporal resolution without excessively degrading signal-to-noise ratio consists in the use of high magnetic field intensity fMRI units. Besides, high field units make the use of more demanding fMRI paradigms, like single trial event related studies, much more compatible with the need of a solid statistical evaluation. This has notably promoted the diffusion of high field MRI units for human studies throughout the world, with very high field MRI units, up to 8 T, working in a few research centres, and a larger number of MRI units with field intensity ranging between 3 and 5 T. PMID:14680904

  8. Diagnostic value of MRI for odontogenic tumours

    PubMed Central

    Fujita, M; Matsuzaki, H; Yanagi, Y; Hara, M; Katase, N; Hisatomi, M; Unetsubo, T; Konouchi, H; Nagatsuka, H; Asaumi, J-I

    2013-01-01

    Objectives: To evaluate the diagnostic value of MRI for odontogenic tumours. Materials and methods: 51 patients with odontogenic tumours were subjected to pre-operative MRI examinations. For tumours with liquid components, i.e. ameloblastomas and keratocystic odontogenic tumours (KCOTs), the signal intensity (SI) uniformity of their cystic components (U?) was calculated and then their U? values were compared. For tumours with solid components that had been examined using dynamic contrast-enhanced MRI (DCE-MRI), their CImax (maximum contrast index), Tmax (the time when CImax occurred), CIpeak (CImax?×?0.90), Tpeak (the time when CIpeak occurred) and CI300 (i.e. the CI observed at 300?s after contrast medium injection) values were determined from CI curves. We then classified the odontogenic tumours according to their DCE-MRI parameters. Results: Significant differences between the U? values of the ameloblastomas and KCOT were observed on T1 weighted images, T2 weighted images and short TI inversion recovery images. Depending on their DCE-MRI parameters, we classified the odontogenic tumours into the following five types: Type A, CIpeak?>?2.0 and Tpeak??2.0 and Tmax??2.0 and Tmax?>?600?s; Type E, CI300??600?s. Conclusion: Cystic component SI uniformity was found to be useful for differentiating between ameloblastomas and KCOT. However, the DCE-MRI parameters of odontogenic tumours, except for odontogenic fibromas and odontogenic myxomas, contributed little to their differential diagnosis. PMID:23468124

  9. MRI in local staging of rectal cancer: an update

    PubMed Central

    Tapan, Ümit; Özbayrak, Mustafa; Tatl?, Servet

    2014-01-01

    Preoperative imaging for staging of rectal cancer has become an important aspect of current approach to rectal cancer management, because it helps to select suitable patients for neoadjuvant chemoradiotherapy and determine the appropriate surgical technique. Imaging modalities such as endoscopic ultrasonography, computed tomography, and magnetic resonance imaging (MRI) play an important role in assessing the depth of tumor penetration, lymph node involvement, mesorectal fascia and anal sphincter invasion, and presence of distant metastatic diseases. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer. However, high-resolution phased-array MRI is recommended as a standard imaging modality for preoperative local staging of rectal cancer, with excellent soft tissue contrast, multiplanar capability, and absence of ionizing radiation. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique such as diffusion-weighted imaging and dynamic contrast-enhanced MRI. PMID:25010367

  10. Benchmarking the ERG valve tip and MRI Interventions Smart Flow neurocatheter convection-enhanced delivery system's performance in a gel model of the brain: employing infusion protocols proposed for gene therapy for Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Sillay, Karl; Schomberg, Dominic; Hinchman, Angelica; Kumbier, Lauren; Ross, Chris; Kubota, Ken; Brodsky, Ethan; Miranpuri, Gurwattan

    2012-04-01

    Convection-enhanced delivery (CED) is an advanced infusion technique used to deliver therapeutic agents into the brain. CED has shown promise in recent clinical trials. Independent verification of published parameters is warranted with benchmark testing of published parameters in applicable models such as gel phantoms, ex vivo tissue and in vivo non-human animal models to effectively inform planned and future clinical therapies. In the current study, specific performance characteristics of two CED infusion catheter systems, such as backflow, infusion cloud morphology, volume of distribution (mm3) versus the infused volume (mm3) (Vd/Vi) ratios, rate of infusion (µl min-1) and pressure (mmHg), were examined to ensure published performance standards for the ERG valve-tip (VT) catheter. We tested the hypothesis that the ERG VT catheter with an infusion protocol of a steady 1 µl min-1 functionality is comparable to the newly FDA approved MRI Interventions Smart Flow (SF) catheter with the UCSF infusion protocol in an agarose gel model. In the gel phantom models, no significant difference was found in performance parameters between the VT and SF catheter. We report, for the first time, such benchmark characteristics in CED between these two otherwise similar single-end port VT with stylet and end-port non-stylet infusion systems. Results of the current study in agarose gel models suggest that the performance of the VT catheter is comparable to the SF catheter and warrants further investigation as a tool in the armamentarium of CED techniques for eventual clinical use and application.

  11. MRI in perianal fistulae

    PubMed Central

    Khera, Pushpinder S; Badawi, Hesham A; Afifi, Ahmed H

    2010-01-01

    MRI has become the method of choice for evaluating perianal fistulae due to its ability to display the anatomy of the sphincter muscles orthogonally, with good contrast resolution. In this article we give an outline of the classification of perianal fistulae and present a pictorial assay of sphincter anatomy and the MRI findings in perianal fistulae. This study is based on a retrospective analysis of 43 patients with a clinical diagnosis of perianal fistula. MRI revealed a total of 44 fistulae in 35 patients; eight patients had only perianal sinuses. PMID:20351996

  12. Distinguished The Anatomy of A Disaster

    E-print Network

    Aydilek, Ahmet

    Distinguished 2006 Series The Anatomy of A Disaster ED LINK Wednesday, May 10, 2006 12:00 PM - 1 generated by Katrina? What are the lessons learned for building back a more resilient and reliant hurricane

  13. Distinguishability, classical information of quantum operations

    E-print Network

    Dong Yang

    2005-04-09

    A basic property of distinguishability is that it is non-increasing under further quantum operations. Following this, we generalize two measures of distinguishability of pure states--fidelity and von Neumann entropy, to mixed states as self-consistent measures. Then we extend these two measures to quantum operations. The information-theoretic point of the generalized Holevo quantity of an ensemble of quantum operations is constructed. Preferably it is an additive measure. The exact formula for SU(2) ensemble is presented. With the aid of the formula, we show Jozsa-Schlienz paradox that states as a whole are less distinguishable while all pairwise are more distinguishable in an ensemble of quantum states, also occurs in an ensemble of quantum operations, even in the minimal dimensional case SU(2) ensemble.

  14. Cryptographic Distinguishability Measures for Quantum Mechanical States

    E-print Network

    Christopher A. Fuchs; Jeroen van de Graaf

    1998-04-03

    This paper, mostly expository in nature, surveys four measures of distinguishability for quantum-mechanical states. This is done from the point of view of the cryptographer with a particular eye on applications in quantum cryptography. Each of the measures considered is rooted in an analogous classical measure of distinguishability for probability distributions: namely, the probability of an identification error, the Kolmogorov distance, the Bhattacharyya coefficient, and the Shannon distinguishability (as defined through mutual information). These measures have a long history of use in statistical pattern recognition and classical cryptography. We obtain several inequalities that relate the quantum distinguishability measures to each other, one of which may be crucial for proving the security of quantum cryptographic key distribution. In another vein, these measures and their connecting inequalities are used to define a single notion of cryptographic exponential indistinguishability for two families of quantum states. This is a tool that may prove useful in the analysis of various quantum cryptographic protocols.

  15. RESTRICTION FRAGMENT LENGTH POLYMORPHISMS DISTINGUISH ECTOMYCORRHIZAL FUNGI

    EPA Science Inventory

    Basidiomycetous fungi, two saprophytes and three mycorrhizal, were used to assess the specificity of DNA hybridization for distinguishing genera from one another. nterspecific comparisons were done with several isolates of mycorrhizal fungi, Laccaria bicolor and L. laccata, colle...

  16. Shoulder MRI scan

    MedlinePLUS

    ... contains no radiation. No side effects from the magnetic fields and radio waves have been reported. The most ... health care provider before the test. The strong magnetic fields created during an MRI can cause heart pacemakers ...

  17. Arm MRI scan

    MedlinePLUS

    ... and MRI In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: ... resonance imaging: In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: ...

  18. Abdominal MRI scan

    MedlinePLUS

    Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen ... use ionizing radiation. No side effects from the magnetic fields and radio waves have been reported. The ...

  19. MRI Scans - Multiple Languages: MedlinePlus

    MedlinePLUS

    ... Resonance Imaging) (Arabic) ??????? Bilingual PDF Health Information Translations Chinese - Simplified (????) MRI (Magnetic Resonance Imaging) ??????(MRI) - ???? (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (????) MRI (Magnetic Resonance Imaging) ??????( ...

  20. Microtesla MRI with dynamic nuclear polarization

    NASA Astrophysics Data System (ADS)

    Zotev, Vadim S.; Owens, Tuba; Matlashov, Andrei N.; Savukov, Igor M.; Gomez, John J.; Espy, Michelle A.

    2010-11-01

    Magnetic resonance imaging at microtesla fields is a promising imaging method that combines the pre-polarization technique and broadband signal reception by superconducting quantum interference device (SQUID) sensors to enable in vivo MRI at microtesla-range magnetic fields similar in strength to the Earth magnetic field. Despite significant advances in recent years, the potential of microtesla MRI for biomedical imaging is limited by its insufficient signal-to-noise ratio due to a relatively low sample polarization. Dynamic nuclear polarization (DNP) is a widely used approach that allows polarization enhancement by 2-4 orders of magnitude without an increase in the polarizing field strength. In this work, the first implementation of microtesla MRI with Overhauser DNP and SQUID signal detection is described. The first measurements of carbon-13 NMR spectra at microtesla fields are also reported. The experiments were performed at the measurement field of 96 ?T, corresponding to Larmor frequency of 4 kHz for protons and 1 kHz for carbon-13. The Overhauser DNP was carried out at 3.5-5.7 mT fields using rf irradiation at 120 MHz. Objects for imaging included water phantoms and a cactus plant. Aqueous solutions of metabolically relevant sodium bicarbonate, pyruvate, alanine, and lactate, labeled with carbon-13, were used for NMR studies. All the samples were doped with TEMPO free radicals. The Overhauser DNP enabled nuclear polarization enhancement by factor as large as -95 for protons and as large as -200 for carbon-13, corresponding to thermal polarizations at 0.33 T and 1.1 T fields, respectively. These results demonstrate that SQUID-based microtesla MRI can be naturally combined with Overhauser DNP in one system, and that its signal-to-noise performance is greatly improved in this case. They also suggest that microtesla MRI can become an efficient tool for in vivo imaging of hyperpolarized carbon-13, produced by low-temperature dissolution DNP.

  1. Microtesla MRI with dynamic nuclear polarization

    PubMed Central

    Zotev, Vadim S.; Owens, Tuba; Matlashov, Andrei N.; Savukov, Igor M.; Gomez, John J.; Espy, Michelle A.

    2010-01-01

    Magnetic resonance imaging at microtesla fields is a promising imaging method that combines the pre-polarization technique and broadband signal reception by superconducting quantum interference device (SQUID) sensors to enable in vivo MRI at microtesla-range magnetic fields similar in strength to the Earth magnetic field. Despite significant advances in recent years, the potential of microtesla MRI for biomedical imaging is limited by its insufficient signal-to-noise ratio due to a relatively low sample polarization. Dynamic nuclear polarization (DNP) is a widely used approach that allows polarization enhancement by two-four orders of magnitude without an increase in the polarizing field strength. In this work, the first implementation of microtesla MRI with Overhauser DNP and SQUID signal detection is described. The first measurements of carbon-13 NMR spectra at microtesla fields are also reported. The experiments were performed at the measurement field of 96 microtesla, corresponding to Larmor frequency of 4 kHz for protons and 1 kHz for carbon-13. The Overhauser DNP was carried out at 3.5 –5.7 mT field using rf irradiation at 120 MHz. Objects for imaging included water phantoms and a cactus plant. Aqueous solutions of metabolically relevant sodium bicarbonate, pyruvate, alanine, and lactate, labeled with carbon-13, were used for NMR studies. All the samples were doped with TEMPO free radicals. The Overhauser DNP enabled nuclear polarization enhancement by factor as high as ?95 for protons and as high as ?200 for carbon-13, corresponding to thermal polarizations at 0.33 T and 1.1 T fields, respectively. These results demonstrate that SQUID-based microtesla MRI can be naturally combined with Overhauser DNP in one system, and that its signal-to-noise performance is greatly improved in this case. They also suggest that microtesla MRI can become an efficient tool for in vivo imaging of hyperpolarized carbon-13, produced by the low-temperature dissolution DNP. PMID:20843715

  2. EEG-informed fMRI analysis during a hand grip task: estimating the relationship between EEG rhythms and the BOLD signal

    PubMed Central

    Sclocco, Roberta; Tana, Maria G.; Visani, Elisa; Gilioli, Isabella; Panzica, Ferruccio; Franceschetti, Silvana; Cerutti, Sergio; Bianchi, Anna M.

    2014-01-01

    In the last decade, an increasing interest has arisen in investigating the relationship between the electrophysiological and hemodynamic measurements of brain activity, such as EEG and (BOLD) fMRI. In particular, changes in BOLD have been shown to be associated with changes in the spectral profile of neural activity, rather than with absolute power. Concurrently, recent findings showed that different EEG rhythms are independently related to changes in the BOLD signal: therefore, it would be also important to distinguish between the contributions of the different EEG rhythms to BOLD fluctuations when modeling the relationship between the two signals. Here we propose a method to perform EEG-informed fMRI analysis where the changes in the spectral profile are modeled, and, at the same time, the distinction between rhythms is preserved. We compared our model with two other frequency-dependent regressors modeling using simultaneous EEG-fMRI data from healthy subjects performing a motor task. Our results showed that the proposed method better captures the correlations between BOLD signal and EEG rhythms modulations, identifying task-related, well localized activated volumes. Furthermore, we showed that including among the regressors also EEG rhythms not primarily involved in the task enhances the performance of the analysis, even when only correlations with BOLD signal and specific EEG rhythms are explored. PMID:24744720

  3. Beyond Benford's Law: Distinguishing Noise from Chaos

    PubMed Central

    Li, Qinglei; Fu, Zuntao; Yuan, Naiming

    2015-01-01

    Determinism and randomness are two inherent aspects of all physical processes. Time series from chaotic systems share several features identical with those generated from stochastic processes, which makes them almost undistinguishable. In this paper, a new method based on Benford's law is designed in order to distinguish noise from chaos by only information from the first digit of considered series. By applying this method to discrete data, we confirm that chaotic data indeed can be distinguished from noise data, quantitatively and clearly. PMID:26030809

  4. Children distinguish between positive pride and hubris.

    PubMed

    Nelson, Nicole L; Russell, James A

    2015-11-01

    Adults distinguish expressions of hubris from those of positive pride. To determine whether children (N = 183; 78-198 months old) make a similar distinction, we asked them to attribute emotion labels and a variety of social characteristics to dynamic expressions intended to convey hubris and positive pride. Like adults, children attributed different emotion labels to the expressions, and this tendency increased with age. Girls were more likely to distinguish between the expressions than boys were. Children also associated more positive social characteristics with the expression of positive pride and more negative characteristics with the expression of hubris. (PsycINFO Database Record PMID:26347987

  5. Magnetic Resonance Imaging (MRI): Brain

    MedlinePLUS

    ... Kids Deal With Bullies Pregnant? What to Expect Magnetic Resonance Imaging (MRI): Brain KidsHealth > Parents > Doctors & Hospitals > Medical Tests & Exams > Magnetic Resonance Imaging (MRI): Brain Print A A A ...

  6. Improvements in Low Field MRI 

    E-print Network

    Ogier, Stephen E

    2013-02-01

    The world of clinical magnetic resonance imaging (MRI) is presently dominated by multi-million dollar machines that use large superconducting magnets to generate very high quality images. It is possible to perform MRI at lower magnetic field...

  7. Radiotherapy planning using MRI.

    PubMed

    Schmidt, Maria A; Payne, Geoffrey S

    2015-11-21

    The use of magnetic resonance imaging (MRI) in radiotherapy (RT) planning is rapidly expanding. We review the wide range of image contrast mechanisms available to MRI and the way they are exploited for RT planning. However a number of challenges are also considered: the requirements that MR images are acquired in the RT treatment position, that they are geometrically accurate, that effects of patient motion during the scan are minimized, that tissue markers are clearly demonstrated, that an estimate of electron density can be obtained. These issues are discussed in detail, prior to the consideration of a number of specific clinical applications. This is followed by a brief discussion on the development of real-time MRI-guided RT. PMID:26509844

  8. Radiotherapy planning using MRI

    NASA Astrophysics Data System (ADS)

    Schmidt, Maria A.; Payne, Geoffrey S.

    2015-11-01

    The use of magnetic resonance imaging (MRI) in radiotherapy (RT) planning is rapidly expanding. We review the wide range of image contrast mechanisms available to MRI and the way they are exploited for RT planning. However a number of challenges are also considered: the requirements that MR images are acquired in the RT treatment position, that they are geometrically accurate, that effects of patient motion during the scan are minimized, that tissue markers are clearly demonstrated, that an estimate of electron density can be obtained. These issues are discussed in detail, prior to the consideration of a number of specific clinical applications. This is followed by a brief discussion on the development of real-time MRI-guided RT.

  9. MRI features of breast lymphoma: preliminary experience in seven cases

    PubMed Central

    Wang, Lijun; Wang, Dengbin; Chai, Weimin; Fei, Xiaochun; Luo, Ran; Li, Xiaoxiao

    2015-01-01

    PURPOSE We aimed to evaluate the imaging features of breast lymphoma using magnetic resonance imaging (MRI). METHODS This retrospective study consisted of seven patients with pathologically confirmed breast lymphoma. The breast lymphomas were primary in six patients and secondary in one patient. All patients underwent preoperative dynamic contrast-enhanced MRI and one underwent additional diffusion-weighted imaging (DWI) with a b value of 600 s/mm2. Morphologic characteristics, enhancement features, and apparent diffusion coefficient (ADC) values were reviewed. RESULTS On MRI, three patients presented with a single mass, one with two masses, two with multiple masses, and one with a single mass and a contralateral focal enhancement. The MRI features of the eight biopsied masses in seven patients were analyzed. On MRI, the margins were irregular in six masses (75%) and spiculated in two (25%). Seven masses (87.5%) displayed homogeneous internal enhancement, while one (12.5%) showed rim enhancement. Seven masses (87.5%) showed a washout pattern and one (12.5%) showed a plateau pattern. The penetrating vessel sign was found in two masses (25%). One patient with two masses underwent DWI. Both masses showed hyperintense signal on DWI with ADC values of 0.867×10?3 mm2/s and 0.732×10?3 mm2/s, respectively. CONCLUSION Breast lymphoma commonly presents as a homogeneously enhancing mass with irregular margins and displays a washout curve pattern on dynamic MRI. A low ADC value may also indicate a possible diagnosis of breast lymphoma. PMID:26380896

  10. Polarized noble gas MRI

    SciTech Connect

    Brookeman, James R.; Mugler, John P. III; Lange, Eduard E. de; Knight-Scott, Jack; Maier, Therese; Bogorad, Paul; Driehuys, Bastiaan; Cates, Gordon; Happer, William; Daniel, Thomas M.; Truwit, Jonathon D.

    1998-01-20

    The development of convenient methods to polarize liter quantities of the noble gases helium-3 and xenon-129 has provided the opportunity for a new MRI method to visualize the internal air spaces of the human lung. These spaces are usually poorly seen with hydrogen-based MRI, because of the limited water content of the lung and the low thermal polarization of the water protons achieved in conventional magnets. In addition, xenon, which has a relatively high solubility and a sufficiently persistent polarization level in blood and biological tissue, offers the prospect of providing perfusion images of the lung, brain and other organs.

  11. Introduction Magnetic Resonance Imaging (MRI)

    E-print Network

    Wirosoetisno, Djoko

    Introduction Statistics Magnetic Resonance Imaging (MRI) Statistics in the UK Statistics at UCL and Beyond #12;Introduction Statistics Magnetic Resonance Imaging (MRI) Statistics in the UK Statistics Magnetic Resonance Imaging (MRI) Statistics in the UK Statistics at UCL Outline Why do Statistics? Some

  12. "Distinguished Alumni Award Dr. Sultana Nahar"

    E-print Network

    Nahar, Sultana Nurun

    - national Society of Muslim Women in Science". She has also founded STEM programs in several countries, especially women in developing countries. A role model for Muslim woman, she is the founder of "The Inter State of Women of Wayne. It is an honor to bestow upon her today the Distinguished Alumni Award. 1 #12;

  13. General neighbour-distinguishing index Ervin Gyoria,

    E-print Network

    of colours of their incident edges. Keywords: Edge colouring; Colour set; General neighbour-distin- guishing a non-negative integer. A (general) k-edge-colouring of G is a mapping : E(G) k i=1{i}. The colour set #12;is the set S(x) of colours of edges incident to x. The colouring is neighbour- distinguishing

  14. Entropy of Mixing of Distinguishable Particles

    ERIC Educational Resources Information Center

    Kozliak, Evguenii I.

    2014-01-01

    The molar entropy of mixing yields values that depend only on the number of mixing components rather than on their chemical nature. To explain this phenomenon using the logic of chemistry, this article considers mixing of distinguishable particles, thus complementing the well-known approach developed for nondistinguishable particles, for example,…

  15. Distinguishing Disability: Parents, Privilege, and Special Education

    ERIC Educational Resources Information Center

    Ong-Dean, Colin

    2009-01-01

    Students in special education programs can have widely divergent experiences. For some, special education amounts to a dumping ground where schools unload their problem students, while for others, it provides access to services and accommodations that drastically improve chances of succeeding in school and beyond. "Distinguishing Disability"…

  16. Comparative Minicolumnar Morphometry of Three Distinguished Scientists

    ERIC Educational Resources Information Center

    Casanova, Manuel F.; Switala, Andrew E.; Trippe, Juan; Fitzgerald, Michael

    2007-01-01

    It has been suggested that the cell minicolumn is the smallest module capable of information processing within the brain. In this case series, photomicrographs of six regions of interests (Brodmann areas 4, 9, 17, 21, 22, and 40) were analyzed by computerized image analysis for minicolumnar morphometry in the brains of three distinguished

  17. Can medial temporal lobe regions distinguish true from false? An event-related functional MRI study

    E-print Network

    Wagner, Anthony

    of veridical and illusory recognition memory Roberto Cabeza* , Stephen M. Rao , Anthony D. Wagner§ , Andrew R, and then the subjects performed a recognition test includ- ing words presented in the study lists (True items), new of the traces recovered by MTL is still a mystery. What kinds of information does MTL recover? On one hand

  18. SmartPhantom – an fMRI Simulator

    PubMed Central

    Cheng, Hu; Zhao, Qun; Duensing, George R.; Edelstein, Williams A.; Spencer, Diana; Browne, Nick; Saylor, Charles; Limkeman, Mark

    2011-01-01

    Many informatics tools have emerged to process the voluminous and complex data generated by fMRI. The interpretation of fMRI exams are largely determined by these tools. However, their performance is hard to evaluate because there is no independent means of calibration. A novel fMRI calibration system called SmartPhantom has been developed to simulate functional BOLD imaging. SmartPhantom contains a quadrature RF coil, comprising two perpendicular planar loops that can be externally activated or deactivated. The system is able to produce reasonably uniform signal enhancements in a calibration sample surrounded by the two loops during an MRI scan. The enhancement is controlled well in both magnitude and predefined timing, and produces BOLD-like signals. Characteristics of SmartPhantom are discussed in detail, followed by a comparison of fMRI informatics tools. Two fMRI data sets are acquired with the SmartPhantom. One with high SNR provides the calibration. Another with lower SNR is input into three software packages (BrainVoyager, FSL and SPM2) for data preprocessing and statistical analysis. Results from the three packages are compared in both sensitivity of detecting the activation and correlation between the predicted activation and calibration. PMID:16563960

  19. Diffuse optical tomography of breast cancer during neoadjuvant chemotherapy: A case study with comparison to MRI

    E-print Network

    Yodh, Arjun G.

    , in reasonable agreement with magnetic resonance images of the same subject. A decrease in total hemoglobin for assessing tumor re- sponse due to chemotherapy-induced fibrosis.3­5 While magnetic resonance imaging MRI has dynamic contrast-enhanced magnetic resonance imaging DCE-MRI has demonstrated ability to monitor tumor

  20. JUNE 2013 13 MRI is a diagnostic technology enabling high-quality

    E-print Network

    are able to provide high precision and enhanced dexterity. MRI-guided robotic surgery, where a surgeon by a team of researchers at the University of Tokyo and Tokyo Women's Medical College1 . Using six resonance imaging (MRI)-compatible medical devices. Recent advances in fluid-powered medical devices

  1. Evolving role of MRI in Crohn's disease.

    PubMed

    Yacoub, Joseph H; Obara, Piotr; Oto, Aytekin

    2013-06-01

    MR enterography is playing an evolving role in the evaluation of small bowel Crohn's disease (CD). Standard MR enterography includes a combination of rapidly acquired T2 sequence, balanced steady-state acquisition, and contrast enhanced T1-weighted gradient echo sequence. The diagnostic performance of these sequences has been shown to be comparable, and in some respects superior, to other small bowel imaging modalities. The findings of CD on MR enterography have been well described in the literature. New and emerging techniques such as diffusion-weighted imaging (DWI), dynamic contrast enhanced MRI (DCE-MRI), cinematography, and magnetization transfer, may lead to improved accuracy in characterizing the disease. These advanced techniques can provide quantitative parameters that may prove to be useful in assessing disease activity, severity, and response to treatment. In the future, MR enterography may play an increasing role in management decisions for patients with small bowel CD; however, larger studies are needed to validate these emerging MRI parameters as imaging biomarkers. PMID:23712842

  2. MRI driven magnetic microswimmers

    PubMed Central

    Jakab, Péter; Székely, Gábor; Hata, Nobuhiko

    2013-01-01

    Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach. PMID:22037673

  3. Phantom for Diffusion MRI

    Cancer.gov

    Combining a Diffusion MRI phantom with a resolution phantom would allow the same device to be used to calibrate an MR scanner''s image quality and the accuracy and precision of its diffusion measurements. This would be useful particularly for Radiological QA and for use in assuring data quality in longitudinal and multi-subject studies.

  4. Brain MRI findings in Wernicke encephalopathy.

    PubMed

    Wicklund, Meredith R; Knopman, David S

    2013-08-01

    A 71-year-old woman with myelofibrosis on chemotherapy experienced an acute illness with nausea, vomiting, and diarrhea. Two weeks later, she developed an acute confusional state characterized by disorientation and fluctuating alertness with normal speech and language. Her neurologic examination demonstrated an upper motor neuron pattern of right hemiparesis. She reported double vision though ophthalmoparesis was not appreciated. Her gait was normal. While hospitalized, she developed generalized tonic-clonic seizures. Brain MRI revealed a small area of restricted diffusion of the left precentral gyrus (figure). She was diagnosed with a stroke with secondary seizures; however, as the confusional state resolved, she developed profound retrograde and anterograde amnesia. Review of the brain MRI showed high T2 signal in the medial thalamus and contrast enhancement of the mamillary bodies; a diagnosis of Wernicke-Korsakoff syndrome was entertained and she was started on thiamine replacement. The encephalopathy and hemiparesis resolved though she remains severely amnestic. PMID:24195023

  5. Item Memory, Context Memory and the Hippocampus: fMRI Evidence

    ERIC Educational Resources Information Center

    Rugg, Michael D.; Vilberg, Kaia L.; Mattson, Julia T.; Yu, Sarah S.; Johnson, Jeffrey D.; Suzuki, Maki

    2012-01-01

    Dual-process models of recognition memory distinguish between the retrieval of qualitative information about a prior event (recollection), and judgments of prior occurrence based on an acontextual sense of familiarity. fMRI studies investigating the neural correlates of memory encoding and retrieval conducted within the dual-process framework have…

  6. Ultrahigh field MRI in clinical neuroimmunology: a potential contribution to improved diagnostics and personalised disease management.

    PubMed

    Sinnecker, Tim; Kuchling, Joseph; Dusek, Petr; Dörr, Jan; Niendorf, Thoralf; Paul, Friedemann; Wuerfel, Jens

    2015-01-01

    Conventional magnetic resonance imaging (MRI) at 1.5 Tesla (T) is limited by modest spatial resolution and signal-to-noise ratio (SNR), impeding the identification and classification of inflammatory central nervous system changes in current clinical practice. Gaining from enhanced susceptibility effects and improved SNR, ultrahigh field MRI at 7 T depicts inflammatory brain lesions in great detail. This review summarises recent reports on 7 T MRI in neuroinflammatory diseases and addresses the question as to whether ultrahigh field MRI may eventually improve clinical decision-making and personalised disease management. PMID:26312125

  7. Distinguishing Provenance Equivalence of Earth Science Data

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt; Yesha, Ye; Halem, M.

    2010-01-01

    Reproducibility of scientific research relies on accurate and precise citation of data and the provenance of that data. Earth science data are often the result of applying complex data transformation and analysis workflows to vast quantities of data. Provenance information of data processing is used for a variety of purposes, including understanding the process and auditing as well as reproducibility. Certain provenance information is essential for producing scientifically equivalent data. Capturing and representing that provenance information and assigning identifiers suitable for precisely distinguishing data granules and datasets is needed for accurate comparisons. This paper discusses scientific equivalence and essential provenance for scientific reproducibility. We use the example of an operational earth science data processing system to illustrate the application of the technique of cascading digital signatures or hash chains to precisely identify sets of granules and as provenance equivalence identifiers to distinguish data made in an an equivalent manner.

  8. LOCC Distinguishable Unentangled Orthonormal Bases are Generic

    E-print Network

    Jiri Lebl; Asif Shakeel; Nolan Wallach

    2015-02-23

    An orthonormal basis consisting of unentangled (pure tensor) elements in a tensor product of Hilbert spaces is an Unentangled Orthogonal Basis (UOB). Bennet et al, in their study of quantum nonlocality without entanglement, noted the lack of LOCC (local operations and classical communication) distinguishability for a specific $3$ qubit UOB. In general, for $n$ qubits, we prove that in its natural structure as a real variety, the space of UOB is a bouquet of products of Riemann spheres parametrized by a class of edge colorings of hypercubes. Its irreducible components of maximum dimension are products of $2^n-1$ two-spheres. Using a theorem of Walgate and Hardy, we observe that the LOCC distinguishable UOB are exactly those in the maximum dimensional components.

  9. Duality of quantum coherence and path distinguishability

    NASA Astrophysics Data System (ADS)

    Bera, Manabendra Nath; Qureshi, Tabish; Siddiqui, Mohd Asad; Pati, Arun Kumar

    2015-07-01

    We derive a generalized wave-particle duality relation for arbitrary multipath quantum interference phenomena. Beyond the conventional notion of the wave nature of a quantum system, i.e., the interference fringe visibility, we introduce a quantifier as the normalized quantum coherence, recently defined in the framework of quantum information theory. To witness the particle nature, we quantify the path distinguishability or the which-path information based on unambiguous quantum state discrimination. Then, the Bohr complementarity principle for multipath quantum interference can be stated as a duality relation between the quantum coherence and the path distinguishability. For two-path interference, the quantum coherence is identical to the interference fringe visibility, and the relation reduces to the well-known complementarity relation. The duality relation continues to hold in the case where mixedness is introduced due to possible decoherence effects.

  10. Familial Identification: Population Structure and Relationship Distinguishability

    PubMed Central

    Rohlfs, Rori V.; Fullerton, Stephanie Malia; Weir, Bruce S.

    2012-01-01

    With the expansion of offender/arrestee DNA profile databases, genetic forensic identification has become commonplace in the United States criminal justice system. Implementation of familial searching has been proposed to extend forensic identification to family members of individuals with profiles in offender/arrestee DNA databases. In familial searching, a partial genetic profile match between a database entrant and a crime scene sample is used to implicate genetic relatives of the database entrant as potential sources of the crime scene sample. In addition to concerns regarding civil liberties, familial searching poses unanswered statistical questions. In this study, we define confidence intervals on estimated likelihood ratios for familial identification. Using these confidence intervals, we consider familial searching in a structured population. We show that relatives and unrelated individuals from population samples with lower gene diversity over the loci considered are less distinguishable. We also consider cases where the most appropriate population sample for individuals considered is unknown. We find that as a less appropriate population sample, and thus allele frequency distribution, is assumed, relatives and unrelated individuals become more difficult to distinguish. In addition, we show that relationship distinguishability increases with the number of markers considered, but decreases for more distant genetic familial relationships. All of these results indicate that caution is warranted in the application of familial searching in structured populations, such as in the United States. PMID:22346758

  11. Usefulness of cardiac MRI in the prognosis and follow-up of ischemic heart disease.

    PubMed

    Hidalgo, A; Pons-Lladó, G

    2015-01-01

    Cardiac magnetic resonance imaging (MRI) is an important tool that makes it possible to evaluate patients with cardiovascular disease; in addition to infarction and alterations in myocardial perfusion, cardiac MRI is useful for evaluating other phenomena such as microvascular obstruction and ischemia. The main prognostic factors in cardiac MRI are ventricular dysfunction, necrosis in late enhancement sequences, and ischemia in stress sequences. In acute myocardial infarction, cardiac MRI can evaluate the peri-infarct zone and quantify the size of the infarct. Furthermore, cardiac MRI's ability to detect and evaluate microvascular obstruction makes it a fundamental tool for establishing the prognosis of ischemic heart disease. In patients with chronic ischemic heart disease, cardiac MRI can detect ischemia induced by pharmacological stress and can diagnose infarcts that can be missed on other techniques. PMID:25648795

  12. Pushing spatial and temporal resolution for functional and diffusion MRI in the Human Connectome Project.

    PubMed

    U?urbil, Kamil; Xu, Junqian; Auerbach, Edward J; Moeller, Steen; Vu, An T; Duarte-Carvajalino, Julio M; Lenglet, Christophe; Wu, Xiaoping; Schmitter, Sebastian; Van de Moortele, Pierre Francois; Strupp, John; Sapiro, Guillermo; De Martino, Federico; Wang, Dingxin; Harel, Noam; Garwood, Michael; Chen, Liyong; Feinberg, David A; Smith, Stephen M; Miller, Karla L; Sotiropoulos, Stamatios N; Jbabdi, Saad; Andersson, Jesper L R; Behrens, Timothy E J; Glasser, Matthew F; Van Essen, David C; Yacoub, Essa

    2013-10-15

    The Human Connectome Project (HCP) relies primarily on three complementary magnetic resonance (MR) methods. These are: 1) resting state functional MR imaging (rfMRI) which uses correlations in the temporal fluctuations in an fMRI time series to deduce 'functional connectivity'; 2) diffusion imaging (dMRI), which provides the input for tractography algorithms used for the reconstruction of the complex axonal fiber architecture; and 3) task based fMRI (tfMRI), which is employed to identify functional parcellation in the human brain in order to assist analyses of data obtained with the first two methods. We describe technical improvements and optimization of these methods as well as instrumental choices that impact speed of acquisition of fMRI and dMRI images at 3T, leading to whole brain coverage with 2 mm isotropic resolution in 0.7 s for fMRI, and 1.25 mm isotropic resolution dMRI data for tractography analysis with three-fold reduction in total dMRI data acquisition time. Ongoing technical developments and optimization for acquisition of similar data at 7 T magnetic field are also presented, targeting higher spatial resolution, enhanced specificity of functional imaging signals, mitigation of the inhomogeneous radio frequency (RF) fields, and reduced power deposition. Results demonstrate that overall, these approaches represent a significant advance in MR imaging of the human brain to investigate brain function and structure. PMID:23702417

  13. Periodic changes in fMRI connectivity

    PubMed Central

    Handwerker, Daniel A.; Roopchansingh, Vinai; Gonzalez-Castillo, Javier; Bandettini, Peter A.

    2014-01-01

    The first two decades of brain research using fMRI have been dominated by studies that measure signal changes in response to a presented task. A rapidly increasing number of studies are showing that consistent activation maps appear by assessment of signal correlations during time periods in which the subjects were not directed to perform any specific task (i.e. “resting state correlations”). Even though neural interactions can happen on much shorter time scales, most “resting state” studies assess these temporal correlations over a period of about 5 to 10 minutes. Here we investigate how these temporal correlations change on a shorter time scale. We examine changes in brain correlations to the posterior cingulate cortex (PCC) across a 10 minutes scan. We show: (1) fMRI correlations fluctuate over time, (2) these fluctuations can be periodic, and (3) correlations between the PCC and other brain regions fluctuate at distinct frequencies. While the precise frequencies of correlation fluctuations vary across subjects and runs, it is still possible to parse brain regions and combinations of brain regions based on fluctuation frequency differences. To evaluate the potential biological significance of these empirical observations, we then use synthetic time series data with identical amplitude spectra, but randomized phase to show that similar effects can still appear even if the timing relationships between voxels are randomized. This implies that observed correlation fluctuations could occur between regions with distinct amplitude spectra, whether or not there are dynamic changes in neural connectivity between such regions. As more studies of brain connectivity dynamics appear, particularly studies using correlation as a key metric, it is vital to better distinguish true neural connectivity dynamics from connectivity fluctuations that are inherently part of this method. Our results also highlight the rich information in the power spectra of fMRI data that can be used to parse brain regions. PMID:22796990

  14. Occupational exposure in MRI

    PubMed Central

    Mcrobbie, D W

    2012-01-01

    This article reviews occupational exposure in clinical MRI; it specifically considers units of exposure, basic physical interactions, health effects, guideline limits, dosimetry, results of exposure surveys, calculation of induced fields and the status of the European Physical Agents Directive. Electromagnetic field exposure in MRI from the static field B0, imaging gradients and radiofrequency transmission fields induces electric fields and currents in tissue, which are responsible for various acute sensory effects. The underlying theory and its application to the formulation of incident and induced field limits are presented. The recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) Bundesministerium für Arbeit und Soziales and Institute of Electrical and Electronics Engineers limits for incident field exposure are interpreted in a manner applicable to MRI. Field measurements show that exposure from movement within the B0 fringe field can exceed ICNIRP reference levels within 0.5 m of the bore entrance. Rate of change of field dB/dt from the imaging gradients is unlikely to exceed the new limits, although incident field limits can be exceeded for radiofrequency (RF) exposure within 0.2–0.5 m of the bore entrance. Dosimetric surveys of routine clinical practice show that staff are exposed to peak values of 42±24% of B0, with time-averaged exposures of 5.2±2.8 mT for magnets in the range 0.6–4 T. Exposure to time-varying fields arising from movement within the B0 fringe resulted in peak dB/dt of approximately 2 T s?1. Modelling of induced electric fields from the imaging gradients shows that ICNIRP-induced field limits are unlikely to be exceeded in most situations; however, movement through the static field may still present a problem. The likely application of the limits is discussed with respect to the reformulation of the European Union (EU) directive and its possible implications for MRI. PMID:22457400

  15. Quantum correlations and distinguishability of quantum states

    SciTech Connect

    Spehner, Dominique

    2014-07-15

    A survey of various concepts in quantum information is given, with a main emphasis on the distinguishability of quantum states and quantum correlations. Covered topics include generalized and least square measurements, state discrimination, quantum relative entropies, the Bures distance on the set of quantum states, the quantum Fisher information, the quantum Chernoff bound, bipartite entanglement, the quantum discord, and geometrical measures of quantum correlations. The article is intended both for physicists interested not only by collections of results but also by the mathematical methods justifying them, and for mathematicians looking for an up-to-date introductory course on these subjects, which are mainly developed in the physics literature.

  16. Perception of dim targets on dark backgrounds in MRI

    NASA Astrophysics Data System (ADS)

    Tisdall, M. Dylan; Atkins, M. Stella

    2007-03-01

    Some diagnostic tasks in MRI involve determining the presence of a faint feature (target) relative to a dark background. In MR images produced by taking pixel magnitudes it is well known that the contrast between faint features and dark backgrounds is reduced due to the Rician noise distribution. In an attempt to enhance detection we implemented three different MRI reconstruction algorithms: the normal magnitude, phase-corrected real, and a wavelet thresholding algorithm designed particularly for MRI noise suppression and contrast enhancement. To compare these reconstructions, we had volunteers perform a two-alternative forced choice (2AFC) signal detection task. The stimuli were produced from high-field head MRI images with synthetic thermal noise added to ensure realistic backgrounds. Circular targets were located in regions of the image that were dark, but next to bright anatomy. Images were processed using one of the three reconstruction techniques. In addition we compared a channelized Hotelling observer (CHO) to the human observers in this task. We measured the percentage correct in both the human and model observer experiments. Our results showed better performance with the use of magnitude or phase-corrected real images compared to the use of the wavelet algorithm. In particular, artifacts induced by the wavelet algorithm seem to distract some users and produce significant inter-subject variability. This contradicts predictions based only on SNR. The CHO matched the mean human results quite closely, demonstrating that this model observer may be used to simulate human response in MRI target detection tasks.

  17. Sodium MRI: Methods and applications

    PubMed Central

    Madelin, Guillaume; Lee, Jae-Seung; Regatte, Ravinder R.; Jerschow, Alexej

    2014-01-01

    Sodium NMR spectroscopy and MRI have become popular in recent years through the increased availability of high-field MRI scanners, advanced scanner hardware and improved methodology. Sodium MRI is being evaluated for stroke and tumor detection, for breast cancer studies, and for the assessment of osteoarthritis and muscle and kidney functions, to name just a few. In this article, we aim to present an up-to-date review of the theoretical background, the methodology, the challenges and limitations, and current and potential new applications of sodium MRI. PMID:24815363

  18. The Topography of Comet Tempel 1 as Distinguished From Images of the Deep Impact Mission

    NASA Astrophysics Data System (ADS)

    Gaeman, Jodi; Farnham, T. L.; A'Hearn, M. F.

    2007-10-01

    In this poster, we present the first elevation measurements of surface features on comet Tempel 1. We report on a project that involves determining the topography of comet Tempel 1, which was impacted during the Deep Impact mission, to provide more detail regarding the comet's surface structure for further analysis of the evolutionary processes cometary bodies undergo. We estimate the topography using data returned from the Deep Impact spacecraft, including Impactor Targeting Sensor (ITS) and Medium Resolution Instrument (MRI) images. Stereo pair images are used as the main method of identifying the relief of the topographical features. There are two sources from which the elevation is derived. The first is the parallax resulting from the different trajectories of the ITS and MRI data; the second is the parallax attributed to the time difference between MRI images. The best resolution, limited by the combination of MRI and ITS data, is about 8 meters per pixel, which limits the range of elevations we can determine. As determining elevation relies on the position of the sun with respect to the comet, the study of the comet's topography also yields some understanding of the material of the comet, as it is necessary to sort those features with natural brightness variations due to composition from those casting shadows. Because data taken during the Deep Impact mission only distinguishably cover a portion of the comet's surface, not all surface features can be analyzed. In this work we determine, map, and then analyze those areas that have sufficient stereo coverage. The determination of the comet's morphology will lead to a better understanding of the stability of its varying structures and thus perhaps the material of which it is composed. This work is funded by NASA's Planetary Data System (PDS) College Student Investigator (CSI) program.

  19. Magnetic Resonance Imaging (MRI) during Pregnancy

    MedlinePLUS

    ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor wants to perform a magnetic resonance imaging (MRI) exam, there is a possibility ...

  20. Jagadish Shukla Distinguished University Professor, George Mason University (GMU)

    E-print Network

    Straus, David M.

    1 Jagadish Shukla Distinguished University Professor, George Mason University (GMU) President;2 CIRRICULUM VITAE OF JAGADISH SHUKLA: RESUME ADDRESS: Distinguished University Professor, George Mason of Technology (Meteorology), USA PROFESSIONAL EXPERIENCE: 2003- present Chairman, Climate Dynamics, George Mason

  1. Learning Comprehensible Relational Features to Distinguish Subfossil Decapod

    E-print Network

    Goadrich, Mark

    Learning Comprehensible Relational Features to Distinguish Subfossil Decapod Crustacean Dactyls- gramming to a new domain involving decapod crustacean claws. We find that we can distinguish dactyl shapes automatically learned quantitative taxonomic keys. 1 Introduction Because decapod crustacean claws

  2. Distinguishing Asthma Phenotypes Using Machine Learning Approaches.

    PubMed

    Howard, Rebecca; Rattray, Magnus; Prosperi, Mattia; Custovic, Adnan

    2015-07-01

    Asthma is not a single disease, but an umbrella term for a number of distinct diseases, each of which are caused by a distinct underlying pathophysiological mechanism. These discrete disease entities are often labelled as 'asthma endotypes'. The discovery of different asthma subtypes has moved from subjective approaches in which putative phenotypes are assigned by experts to data-driven ones which incorporate machine learning. This review focuses on the methodological developments of one such machine learning technique-latent class analysis-and how it has contributed to distinguishing asthma and wheezing subtypes in childhood. It also gives a clinical perspective, presenting the findings of studies from the past 5 years that used this approach. The identification of true asthma endotypes may be a crucial step towards understanding their distinct pathophysiological mechanisms, which could ultimately lead to more precise prevention strategies, identification of novel therapeutic targets and the development of effective personalized therapies. PMID:26143394

  3. Restricted connections among distinguished players support cooperation

    NASA Astrophysics Data System (ADS)

    Perc, Matjaž; Szolnoki, Attila; Szabó, György

    2008-12-01

    We study the evolution of cooperation within the spatial prisoner’s dilemma game on a square lattice where a fraction of players ? can spread their strategy more easily than the rest due to a predetermined larger teaching capability. In addition, players characterized by the larger teaching capability are allowed to temporarily link with distant opponents of the same kind with probability p , thus introducing shortcut connections among the distinguished players. We show that these additional temporary connections are able to sustain cooperation throughout the whole range of the temptation to defect. Remarkably, we observe that, as the temptation to defect increases the optimal ? decreases, and moreover only minute values of p warrant the best promotion of cooperation. Our study thus indicates that influential individuals must be few and sparsely connected in order for cooperation to thrive in a defection-prone environment.

  4. Inequality indicators and distinguishability in economics

    NASA Astrophysics Data System (ADS)

    Rosenblatt, J.; Martinás, K.

    2008-03-01

    Money has a material counterpart, such as banknotes or coins, and an ideal expression, monetary units. In the latter case, it is boson-like: individual incomes have no a priori limit, and their units are not distinguishable from each other in economic processes. Individuals, on the other hand, usually occupy one job at a time which makes them akin to fermions. We apply to individual incomes down-to-earth statistical calculations, similar to those for quantum particles, and obtain expressions for the cumulative distribution function, probability density and Lorenz function resulting from the simultaneous use of both statistics. They provide extremely good fits to corresponding data on French income distributions. On this basis, we propose a new entropic inequality indicator.

  5. Do open clusters have distinguishable chemical signatures?

    E-print Network

    Blanco-Cuaresma, S; Heiter, U

    2015-01-01

    Past studies have already shown that stars in open clusters are chemically homogeneous (e.g. De Silva et al. 2006, 2007 and 2009). These results support the idea that stars born from the same giant molecular cloud should have the same chemical composition. In this context, the chemical tagging technique was proposed by Freeman et al. 2002. The principle is to recover disrupted stellar clusters by looking only to the stellar chemical composition. In order to evaluate the feasibility of this approach, it is necessary to test if we can distinguish between stars born from different molecular clouds. For this purpose, we studied the chemical composition of stars in 32 old and intermediate-age open clusters, and we applied machine learning algorithms to recover the original cluster by only considering the chemical signatures.

  6. Do open clusters have distinguishable chemical signatures?

    NASA Astrophysics Data System (ADS)

    Blanco-Cuaresma, S.; Soubiran, C.; Heiter, U.

    2014-07-01

    Past studies have already shown that stars in open clusters are chemically homogeneous (e.g. De Silva et al. 2006, 2007 and 2009). These results support the idea that stars born from the same giant molecular cloud should have the same chemical composition. In this context, the chemical tagging technique was proposed by Freeman et al. (2002). The principle is to recover disrupted stellar clusters by looking only to the stellar chemical composition. In order to evaluate the feasibility of this approach, it is necessary to test if we can distinguish between stars born from different molecular clouds. For this purpose, we studied the chemical composition of stars in 32 old and intermediate-age open clusters, and we applied machine learning algorithms to recover the original cluster by only considering the chemical signatures.

  7. Defining disruptive coloration and distinguishing its functions

    PubMed Central

    Stevens, Martin; Merilaita, Sami

    2008-01-01

    Disruptive coloration breaks up the shape and destroys the outline of an object, hindering detection. The principle was first suggested approximately a century ago, but, although research has significantly increased, the field remains conceptually unstructured and no unambiguous definition exists. This has resulted in variable use of the term, making it difficult to formulate testable hypotheses that are comparable between studies, slowing down advancement in this field. Related to this, a range of studies do not effectively distinguish between disruption and other forms of camouflage. Here, we give a formal definition of disruptive coloration, reorganize a range of sub-principles involved in camouflage and argue that five in particular are specifically related to disruption: differential blending; maximum disruptive contrast; disruption of surface through false edges; disruptive marginal patterns; and coincident disruptive coloration. We discuss how disruptive coloration can be optimized, how it can relate to other forms of camouflage markings and where future work is particularly needed. PMID:18990673

  8. Detecting and assessing macrophages in vivo to evaluate atherosclerosis noninvasively using molecular MRI

    PubMed Central

    Amirbekian, Vardan; Lipinski, Michael J.; Briley-Saebo, Karen C.; Amirbekian, Smbat; Aguinaldo, Juan Gilberto S.; Weinreb, David B.; Vucic, Esad; Frias, Juan C.; Hyafil, Fabien; Mani, Venkatesh; Fisher, Edward A.; Fayad, Zahi A.

    2007-01-01

    We investigated the ability of targeted immunomicelles to detect and assess macrophages in atherosclerotic plaque using MRI in vivo. There is a large clinical need for a noninvasive tool to assess atherosclerosis from a molecular and cellular standpoint. Macrophages play a central role in atherosclerosis and are associated with plaques vulnerable to rupture. Therefore, macrophage scavenger receptor (MSR) was chosen as a target for molecular MRI. MSR-targeted immunomicelles, micelles, and gadolinium–diethyltriaminepentaacetic acid (DTPA) were tested in ApoE?/? and WT mice by using in vivo MRI. Confocal laser-scanning microscopy colocalization, macrophage immunostaining and MRI correlation, competitive inhibition, and various other analyses were performed. In vivo MRI revealed that at 24 h postinjection, immunomicelles provided a 79% increase in signal intensity of atherosclerotic aortas in ApoE?/? mice compared with only 34% using untargeted micelles and no enhancement using gadolinium–DTPA. Confocal laser-scanning microscopy revealed colocalization between fluorescent immunomicelles and macrophages in plaques. There was a strong correlation between macrophage content in atherosclerotic plaques and the matched in vivo MRI results as measured by the percent normalized enhancement ratio. Monoclonal antibodies to MSR were able to significantly hinder immunomicelles from providing contrast enhancement of atherosclerotic vessels in vivo. Immunomicelles provided excellent validated in vivo enhancement of atherosclerotic plaques. The enhancement seen is related to the macrophage content of the atherosclerotic vessel areas imaged. Immunomicelles may aid in the detection of high macrophage content associated with plaques vulnerable to rupture. PMID:17215360

  9. SQUID-sensor-based ultra-low-field MRI calibration with phantom images: Towards quantitative imaging

    NASA Astrophysics Data System (ADS)

    Dabek, Juhani; Vesanen, Panu T.; Zevenhoven, Koos C. J.; Nieminen, Jaakko O.; Sepponen, Raimo; Ilmoniemi, Risto J.

    2012-11-01

    In ultra-low-field magnetic resonance imaging (ULF MRI), measured resonance signals oscillate at Larmor frequencies around 1 kHz compared to even above 100 MHz in high-field MRI. Thus, detection by induction coils in ULF MRI is not feasible, whereas superconducting quantum interference device (SQUID) sensors can measure these femtotesla-level signals. The signal-to-noise ratio is enhanced by prepolarization in a field that is typically 100-1000 times higher than the field during acquisition. Based on both measurements and simulations, a procedure for calibrating a SQUID-sensor-based MRI system with MR images is presented in this article. Magnetoencephalography (MEG) can be integrated with ULF MRI, and may also benefit from such a calibration procedure. Conventionally, electromagnet probe signals have been used for the SQUID-sensor calibration in MEG; the presented ULF-MRI-based approach using an imaging phantom could replace this procedure in hybrid MEG-MRI or ULF MRI alone. The necessary theory is provided here with experimental verification. The calibration procedure opens the possibility of performing quantitative ULF MRI without sample-specific reference scans.

  10. California Policy Should Distinguish Biofuels by Differential Global Warming Effects

    E-print Network

    Kammen, Daniel M.

    California Policy Should Distinguish Biofuels by Differential Global Warming Effects by Richard J: _______________________________________ Date #12;California Policy Should Distinguish Biofuels by Differential Global Warming Effects Richard J, 2006 #12;#12;ABSTRACT California Policy Should Distinguish Biofuels by Differential Global Warming

  11. MRI breast screening in high-risk women: cancer detection and survival analysis.

    PubMed

    Evans, D Gareth; Gareth, Evans D; Kesavan, Nisha; Nisha, Kesavan; Lim, Yit; Yit, Lim; Gadde, Soujanye; Soujanye, Gadde; Hurley, Emma; Emma, Hurley; Massat, Nathalie J; Maxwell, Anthony J; Ingham, Sarah; Sarah, Ingham; Eeles, Rosalind; Rosalind, Eeles; Leach, Martin O; Howell, Anthony; Anthony, Howell; Duffy, Stephen W; Stephen, Duffy

    2014-06-01

    Women with a genetic predisposition to breast cancer tend to develop the disease at a younger age with denser breasts making mammography screening less effective. The introduction of magnetic resonance imaging (MRI) for familial breast cancer screening programs in recent years was intended to improve outcomes in these women. We aimed to assess whether introduction of MRI surveillance improves 5- and 10-year survival of high-risk women and determine the accuracy of MRI breast cancer detection compared with mammography-only or no enhanced surveillance and compare size and pathology of cancers detected in women screened with MRI + mammography and mammography only. We used data from two prospective studies where asymptomatic women with a very high breast cancer risk were screened by either mammography alone or with MRI also compared with BRCA1/2 carriers with no intensive surveillance. 63 cancers were detected in women receiving MRI + mammography and 76 in women receiving mammography only. Sensitivity of MRI + mammography was 93 % with 63 % specificity. Fewer cancers detected on MRI were lymph node positive compared to mammography/no additional screening. There were no differences in 10-year survival between the MRI + mammography and mammography-only groups, but survival was significantly higher in the MRI-screened group (95.3 %) compared to no intensive screening (73.7 %; p = 0.002). There were no deaths among the 21 BRCA2 carriers receiving MRI. There appears to be benefit from screening with MRI, particularly in BRCA2 carriers. Extended follow-up of larger numbers of high-risk women is required to assess long-term survival. PMID:24687378

  12. Cyclic generalized projection MRI.

    PubMed

    Sarty, Gordon E

    2015-04-01

    Progress in the development of portable MRI hinges on the ability to use lightweight magnets that have non-uniform magnetic fields. An image encoding method and mathematical procedure for recovering the image from the NMR signal from non-uniform magnets with closed isomagnetic contours is given. Individual frequencies in an NMR signal from an object in a non-uniform magnetic field give rise to integrals of the object along contours of constant magnetic field: generalized projections. With closed isomagnetic field contours a simple, cyclic, direct reconstruction of the image from the generalized projections is possible when the magnet and RF transmit coil are held fixed relative to the imaged object while the RF receive coil moves. Numerical simulations, using the Shepp and Logan mathematical phantom, were completed to show that the mathematical method works and to illustrate numerical limitations. The method is numerically verified and exact reconstruction demonstrated for discrete mathematical image phantoms. Correct knowledge of the RF receive field is necessary or severe image distortions will result. The cyclic mathematical reconstruction method presented here will be useful for portable MRI schemes that use non-uniform magnets with closed isomagnetic contours along with mechanically or electronically moving the RF receive coils. PMID:25532468

  13. [Cardiac MRI: technology, clinical applications, and future directions].

    PubMed

    Pesenti-Rossi, D; Peyrou, J; Baron, N; Allouch, P; Aubert, S; Boueri, Z; Livarek, B

    2013-11-01

    The field of cardiovascular MRI has evolved rapidly over the past decade, feeding new applications across a broad spectrum of clinical and research areas. Advances in magnet hardware technology, and key developments such as segmented k-space acquisitions, advanced motion encoding techniques, ultra-rapid perfusion imaging and delayed myocardial enhancement imaging have all contributed to a revolution in how patients with ischemic and non-ischemic heart disease are diagnosed and treated. Actually, cardiac MRI is a widely accepted method as the "gold standard" for detection and characterization of many forms of cardiac diseases. The aim of this review is to present an overview of cardiac MRI technology, advances in clinical applications, and future directions. PMID:24035258

  14. MRI Images Compression Using Curvelets Transforms

    NASA Astrophysics Data System (ADS)

    Beladgham, M.; Hacene, I. Boucli; Taleb-Ahmed, A.; Khélif, M.

    2008-06-01

    In the field of medical diagnostics, interested parties have resorted increasingly to medical imaging, it is well established that the accuracy and completeness of diagnosis are initially connected with the image quality, but the quality of the image is itself dependent on a number of factors including primarily the processing that an image must undergo to enhance its quality. We are interested in MRI medical image compression by Curvelets, of which we have proposed in this paper the compression algorithm FDCT using the wrapping method. In order to enhance the compression algorithm by FDCT, we have compared the results obtained with wavelet and Ridgelet transforms. The results are very satisfactory regarding compression ratio, and the computation time and quality of the compressed image compared to those of traditional methods.

  15. Distinguished Faculty Fellowships 2016 Deans are invited to nominate members of their faculty for Distinguished Faculty Fellowships.

    E-print Network

    Yu, Sheng-Tao

    Distinguished Faculty Fellowships 2016 Deans are invited to nominate members of their faculty for Distinguished Faculty Fellowships. These Fellowships have been created to recognize and provide support/or in the fine and performing arts are nationally distinguished. The Fellowships have a dual purpose: not only

  16. Machine learning algorithm accurately detects fMRI signature of vulnerability to major depression.

    PubMed

    Sato, João R; Moll, Jorge; Green, Sophie; Deakin, John F W; Thomaz, Carlos E; Zahn, Roland

    2015-08-30

    Standard functional magnetic resonance imaging (fMRI) analyses cannot assess the potential of a neuroimaging signature as a biomarker to predict individual vulnerability to major depression (MD). Here, we use machine learning for the first time to address this question. Using a recently identified neural signature of guilt-selective functional disconnection, the classification algorithm was able to distinguish remitted MD from control participants with 78.3% accuracy. This demonstrates the high potential of our fMRI signature as a biomarker of MD vulnerability. PMID:26187550

  17. Adrenal pseudomasses due to varices: angiographic-CT-MRI-pathologic correlations

    SciTech Connect

    Brady, T.M.; Gross, B.H.; Glazer, G.M. Williams, D.M.

    1985-08-01

    Periadrenal and adrenal portosystemic collaterals are a recently reported cause of adrenal pseudotumor on computed tomography (CT). Nine patients with this left adrenal pseudotumor illustrate its typical position and appearance on CT, angiography, CT-angiography, and magnetic resonance imaging (MRI). The anatomic basis for variceal adrenal pseudotumors is the left inferior phrenic vein, which passes immediately anterior to the left adrenal gland and which serves as a collateral pathway from splenic to left renal vein in portal hypertension. Thus, unlike previously described adrenal pseudotumors, these venous collaterals are not anatomically distinguishable from the adrenal gland on CT. Bolus dynamic CT is usually diagnostic, but in equivocal cases, MRI may prove useful.

  18. Is there texture information in standard brain MRI?

    NASA Astrophysics Data System (ADS)

    Soltanian-Zadeh, Hamid; Nezafat, Reza; Windham, Joe P.

    1999-05-01

    We have developed a texture feature extraction method for MRI utilizing the recently developed multiwavelet theory. Texture based features are used in Eigenimage Filtering to enhance analysis results of tumor patient MRI studies. The steps of the proposed method are as follows: (1) Each original image is convolved with a Gaussian filter. This step suppresses the image noise. (2) Each of the resulting images is convolved with eight multiwavelet coefficient matrices. (3) The output of each filter is stored in a separate image (feature plane). This step generates features (images) in which texture information is enhanced. (4) Local energy of each feature is calculated by squaring the feature values. This step converts variance disparities into mean value differences and transforms large values of local pass- band energy into large image gray levels. (5) Eigenimage filter is applied to different sets of MRI images and the results are compared. First, it is applied to the conventional MRI images (T1-weighted, T2-weighted, and proton density weighted). Then, it is applied to the set consisting of these images and the texture feature images generated in the previous step for them. Finally, it is applied to four original images (three conventional and a non-conventional). (6) The eigenimages obtained in the previous step are compared. This step illustrates presence and significance of the texture information present in MRI and role of the proposed method in extracting these features. Applications of the proposed method to MRI studies of brain tumor patients illustrate that the method successfully extracts texture features which are useful in tumor segmentation and characterization.

  19. MRI evaluation of RF ablation scarring for atrial fibrillation treatment

    NASA Astrophysics Data System (ADS)

    Ishihara, Yuri; Nazafat, Reza; Wylie, John V.; Linguraru, Marius G.; Josephson, Mark E.; Howe, Robert D.; Manning, Warren J.; Peters, Dana C.

    2007-03-01

    This study presents a multi-modality image registration method that evaluates left atrial scarring after radiofrequency (RF) ablation for pulmonary vein (PV) isolation. Our group has recently developed a delayed enhancement magnetic resonance imaging (DE-MRI) method with the potential to visualize and monitor non-invasively post-ablation scarring in the left atrium and the PV ostia. We wished to compare the 3D configuration of scarring in the DE-MRI image and the ablation points recorded by electroanatomical mapping (EAM) system, hypothesizing that scarring detected by DE-MRI overlaps with ablation points recorded by the EAM system used in the procedure. Methods and Results: Three data sets, DE-MRI images and pulmonary vein MR angiography (PV-MRA) images, and EAM data (CARTO-XP, Biosense-Webster, Inc., Diamond Bar, CA) from a patient who underwent PV ablation, were used for the multi-modal image registration. Contrast-enhanced MR imaging was performed 38 days after the ablation procedure. PV-MRA and DE-MRI were fused by intensity-based rigid registration. Scar tissue was extracted from the DE-MRI images using multiple threshold values. EAM data was further fused with segmented PV-MRA by the iterative closest point algorithm (ICP). After registration, the distance from PV-MRA to the scar was 2.6 +/- 2.1 mm, and from ablation points to the surface of the scar was 2.5 +/- 2.3 mm. The fused image demonstrates the 3D relationship between the PV ostia, the scar and the EAM recording of ablation points. Conclusion: Multimodal data fusion indicated that the scar tissue lesion after PV isolation showed good overlap with the ablation points.

  20. Molecular MRI of Collagen to Diagnose and Stage Liver Fibrosis

    PubMed Central

    Fuchs, Bryan C.; Wang, Huifang; Yang, Yan; Wei, Lan; Polasek, Miloslav; Schühle, Daniel T.; Lauwers, Gregory Y.; Parkar, Ashfaq; Sinskey, Anthony J.; Tanabe, Kenneth K.; Caravan, Peter

    2013-01-01

    Background & Aims The gold standard in assessing liver fibrosis is biopsy despite limitations like invasiveness and sampling error and complications including morbidity and mortality. Therefore, there is a major unmet medical need to quantify fibrosis noninvasively to facilitate early diagnosis of chronic liver disease and provide a means to monitor disease progression. The goal of this study was to evaluate the ability of several magnetic resonance imaging (MRI) techniques to stage liver fibrosis. Methods A gadolinium (Gd)-based MRI probe targeted to type I collagen (termed EP-3533) was utilized to noninvasively stage liver fibrosis in a carbon tetrachloride (CCl4) mouse model and the results were compared to other MRI techniques including relaxation times, diffusion and magnetization transfer measurements. Results The most sensitive MR biomarker was the change in liver:muscle contrast to noise ratio (?CNR) after EP-3533 injection. We observed a strong positive linear correlation between ?CNR and liver hydroxyproline (i.e. collagen) levels (r=0.89) as well as ?CNR and conventional Ishak fibrosis scoring. In addition, the area under the receiver operating curve (AUR0C) for distinguishing early (Ishak ?3) from late (Ishak ? 4) fibrosis was 0.942±0.052 (p<0.001). By comparison, other MRI techniques were not as sensitive to changes in fibrosis in this model. Conclusions We have developed a MRI technique using a collagen-specific probe for diagnosing and staging liver fibrosis, and validated it in the CCl4 mouse model. This approach should provide a better means to monitor disease progression in patients. PMID:23838178

  1. MRI of plants and foods

    NASA Astrophysics Data System (ADS)

    Van As, Henk; van Duynhoven, John

    2013-04-01

    The importance and prospects for MRI as applied to intact plants and to foods are presented in view of one of humanity's most pressing concerns, the sustainable and healthy feeding of a worldwide increasing population. Intact plants and foods have in common that their functionality is determined by complex multiple length scale architectures. Intact plants have an additional level of complexity since they are living systems which critically depend on transport and signalling processes between and within tissues and organs. The combination of recent cutting-edge technical advances and integration of MRI accessible parameters has the perspective to contribute to breakthroughs in understanding complex regulatory plant performance mechanisms. In food science and technology MRI allows for quantitative multi-length scale structural assessment of food systems, non-invasive monitoring of heat and mass transport during shelf-life and processing, and for a unique view on food properties under shear. These MRI applications are powerful enablers of rationally (re)designed food formulations and processes. Limitations and bottlenecks of the present plant and food MRI methods are mainly related to short T2 values and susceptibility artefacts originating from small air spaces in tissues/materials. We envisage cross-fertilisation of solutions to overcome these hurdles in MRI applications in plants and foods. For both application areas we witness a development where MRI is moving from highly specialised equipment to mobile and downscaled versions to be used by a broad user base in the field, greenhouse, food laboratory or factory.

  2. MRI Technologies in Recent Human Brain Mapping

    NASA Astrophysics Data System (ADS)

    Sasaki, Yuka

    The recent magnetic resonance imaging (MRI) technology and techniques used in human brain mapping are remarkable. They are getting, faster, stronger and better. The advanced MRI technologies and techniques include, but not to limited to, the magnetic resonance imaging at higher magnetic field strengths, diffusion tensor imaging, multimodal neuroimaging, and monkey functional MRI. In this article, these advanced MRI techniques are briefly overviewed.

  3. Review of treatment assessment using DCE-MRI in breast cancer radiation therapy

    PubMed Central

    Wang, Chun-Hao; Yin, Fang-Fang; Horton, Janet; Chang, Zheng

    2014-01-01

    As a noninvasive functional imaging technique, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is being used in oncology to measure properties of tumor microvascular structure and permeability. Studies have shown that parameters derived from certain pharmacokinetic models can be used as imaging biomarkers for tumor treatment response. The use of DCE-MRI for quantitative and objective assessment of radiation therapy has been explored in a variety of methods and tumor types. However, due to the complexity in imaging technology and divergent outcomes from different pharmacokinetic approaches, the method of using DCE-MRI in treatment assessment has yet to be standardized, especially for breast cancer. This article reviews the basic principles of breast DCE-MRI and recent studies using DCE-MRI in treatment assessment. Technical and clinical considerations are emphasized with specific attention to assessment of radiation treatment response. PMID:25332905

  4. Cell tracking with caged xenon: using cryptophanes as MRI reporters upon cellular internalization.

    PubMed

    Klippel, Stefan; Döpfert, Jörg; Jayapaul, Jabadurai; Kunth, Martin; Rossella, Federica; Schnurr, Matthias; Witte, Christopher; Freund, Christian; Schröder, Leif

    2014-01-01

    Caged xenon has great potential in overcoming sensitivity limitations for solution-state NMR detection of dilute molecules. However, no application of such a system as a magnetic resonance imaging (MRI) contrast agent has yet been performed with live cells. We demonstrate MRI localization of cells labeled with caged xenon in a packed-bed bioreactor working under perfusion with hyperpolarized-xenon-saturated medium. Xenon hosts enable NMR/MRI experiments with switchable contrast and selectivity for cell-associated versus unbound cages. We present MR images with 10(3) -fold sensitivity enhancement for cell-internalized, dual-mode (fluorescence/MRI) xenon hosts at low micromolar concentrations. Our results illustrate the capability of functionalized xenon to act as a highly sensitive cell tracer for MRI detection even without signal averaging. The method will bridge the challenging gap for translation to in?vivo studies for the optimization of targeted biosensors and their multiplexing applications. PMID:24307424

  5. Ultraviolet plumage reflectance distinguishes sibling bird species.

    PubMed

    Bleiweiss, Robert

    2004-11-23

    Realistic studies of plumage color need to consider that many birds can see near-UV light, which normal humans cannot perceive. Although previous investigations have revealed that UV-based plumage reflectance is an important component of various intraspecific social signals, the contribution of UV signals to inter-specific divergence and speciation in birds remains largely unexplored. I describe an avian example of an interspecific phenomenon in which related sympatric species that appear similar to humans (sibling species) differ dramatically in the UV. Both UV video images and physical reflectance spectra indicate that the dorsal plumage of the tanager Anisognathus notabilis has a strong UV-limited reflectance band that readily distinguishes this species from its sibling congener Anisognathus flavinuchus. The main human-visible distinction between A. notabilis (olive back) and coexisting A. flavinuchus (black back) also occurs among different geographic populations of A. flavinuchus. Notably, however, olive- and black-backed taxa interbreed (differentiated populations of A. flavinuchus) unless the additional UV distinction is present (A. notabilis vs. A. flavinuchus). Thus, UV-based reflectance can be an essential component of plumage divergence that relates to reproductive isolation, a key attribute of biological species. PMID:15546987

  6. Distinguishing Between Site Waste, Natural, and Other Sources of Contamination at Uranium and Thorium Contaminated Sites - 12274

    SciTech Connect

    Hays, David C.

    2012-07-01

    Uranium and thorium processing and milling sites generate wastes (source, byproduct, or technically enhanced naturally occurring material), that contain contaminants that are similar to naturally occurring radioactive material deposits and other industry wastes. This can lead to mis-identification of other materials as Site wastes. A review of methods used by the US Army Corps of Engineers and the Environmental Protection Agency to distinguish Site wastes from potential other sources, enhanced materials, and natural deposits, at three different thorium mills was conducted. Real case examples demonstrate the importance of understanding the methods of distinguishing wastes. Distinguishing between Site wastes and enhanced Background material can be facilitated by establishing and applying a formal process. Significant project cost avoidance may be realized by distinguishing Site wastes from enhanced NORM. Collection of information on other potential sources of radioactive material and physical information related to the potential for other radioactive material sources should be gathered and reported in the Historical Site Assessment. At a minimum, locations of other such information should be recorded. Site decision makers should approach each Site area with the expectation that non site related radioactive material may be present and have a process in place to distinguish from Site and non Site related materials. (authors)

  7. A LEARNING BY EXAMPLE APPROACH FOR MRI ANALYSIS OF HUMAN BRAIN IN THE CONTEXT OF MENTAL HEALTH

    E-print Network

    Castellani, Umberto

    A LEARNING BY EXAMPLE APPROACH FOR MRI ANALYSIS OF HUMAN BRAIN IN THE CONTEXT OF MENTAL HEALTH for the analysis of human brains in the context of mental health research, i.e. to distinguish between healthy be useful for human brain analysis. ·The results are very promising since up to 82% of patients

  8. MRI Meets MPI: a bimodal MPI-MRI tomograph.

    PubMed

    Vogel, Patrick; Lother, Steffen; Rückert, Martin A; Kullmann, Walter H; Jakob, Peter M; Fidler, Florian; Behr, Volker C

    2014-10-01

    While magnetic particle imaging (MPI) constitutes a novel biomedical imaging technique for tracking superparamagnetic nanoparticles in vivo, unlike magnetic resonance imaging (MRI), it cannot provide anatomical background information. Until now these two modalities have been performed in separate scanners and image co-registration has been hampered by the need to reposition the sample in both systems as similarly as possible. This paper presents a bimodal MPI-MRI-tomograph that combines both modalities in a single system.MPI and MRI images can thus be acquired without moving the sample or replacing any parts in the setup. The images acquired with the presented setup show excellent agreement between the localization of the nanoparticles in MPI and the MRI background data. A combination of two highly complementary imaging modalities has been achieved. PMID:25291350

  9. Demand forecasting and targeting of MRI services.

    PubMed

    Pribyl, S

    1988-05-01

    As more hospitals acquire MRI and freestanding diagnostic imaging centers proliferate, strategies to develop market share must be combined with financial projections from the forecast of demand for MRI services. The second-generation MRI projection method developed by the American Hospital Association provides detailed estimates of inpatient and outpatient CT and MRI scans for 229 international Classification of Diseases codes, which can be used to target specific practitioners and product lines for MRI services. PMID:10287385

  10. MRI of hepatocellular carcinoma: an update of current practices

    PubMed Central

    Arif-Tiwari, Hina; Kalb, Bobby; Chundru, Surya; Sharma, Puneet; Costello, James; Guessner, Rainner W.; Martin, Diego R.

    2014-01-01

    Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and liver transplantation is the optimal treatment for selected patients with HCC and chronic liver disease (CLD). Accurate selection of patients for transplantation is essential to maximize patient outcomes and ensure optimized allocation of donor organs. Magnetic resonance imaging (MRI) is a powerful tool for the detection, characterization, and staging of HCC. In patients with CLD, the MRI findings of an arterial-enhancing mass with subsequent washout and enhancing capsule on delayed interstitial phase images are diagnostic for HCC. Major organizations with oversight for organ donor distribution, such as The Organ Procurement and Transplantation Network (OPTN), accept an imaging diagnosis of HCC, no longer requiring tissue biopsy. In patients that are awaiting transplantation, or are not candidates for liver transplantation, localized therapies such as transarterial chemoembolization and radiofrequency ablation may be offered. MRI can be used to monitor treatment response. The purpose of this review article is to describe the role of imaging methods in the diagnosis, staging, and follow-up of HCC, with particular emphasis on established and evolving MRI techniques employing nonspecific gadolinium chelates, hepatobiliary contrast agents, and diffusion weighted imaging. We also briefly review the recently developed Liver Imaging Reporting and Data System (LI-RADS) formulating a standardized terminology and reporting structure for evaluation of lesions detected in patients with CLD. PMID:24808419

  11. Multiparametric MRI of solid renal masses: pearls and pitfalls.

    PubMed

    Ramamurthy, N K; Moosavi, B; McInnes, M D F; Flood, T A; Schieda, N

    2015-03-01

    Functional imaging [diffusion-weighted imaging (DWI) and dynamic contrast enhancement (DCE)] techniques combined with T2-weighted (T2W) and chemical-shift imaging (CSI), with or without urography, constitutes a comprehensive multiparametric (MP) MRI protocol of the kidneys. MP-MRI of the kidneys can be performed in a time-efficient manner. Breath-hold sequences and parallel imaging should be used to reduce examination time and improve image quality. Increased T2 signal intensity (SI) in a solid renal nodule is specific for renal cell carcinoma (RCC); whereas, low T2 SI can be seen in RCC, angiomyolipoma (AML), and haemorrhagic cysts. Low b-value DWI can replace conventional fat-suppressed T2W. DWI can be performed free-breathing (FB) with two b-values to reduce acquisition time without compromising imaging quality. RCC demonstrates restricted diffusion; however, restricted diffusion is commonly seen in AML and in chronic haemorrhage. CSI must be performed using the correct echo combination at 3 T or T2* effects can mimic intra-lesional fat. Two-dimensional (2D)-CSI has better image quality compared to three-dimensional (3D)-CSI, but volume averaging in small lesions can simulate intra-lesional fat using 2D techniques. SI decrease on CSI is present in both AML and clear cell RCC. Verification of internal enhancement with MRI can be challenging and is improved with image subtraction. Subtraction imaging is prone to errors related to spatial misregistration, which is ameliorated with expiratory phase imaging. SI ratios can be used to confirm subtle internal enhancement and enhancement curves are predictive of RCC subtype. MR urography using conventional extracellular gadolinium must account for T2* effects; however, gadoxetic acid enhanced urography is an alternative. The purpose of this review it to highlight important technical and interpretive pearls and pitfalls encountered with MP-MRI of solid renal masses. PMID:25472466

  12. How do recovery definitions distinguish recovering individuals?

    PubMed Central

    Witbrodt, Jane; Kaskutas, Lee Ann; Grella, Christine E.

    2015-01-01

    Background Six percent of American adults say they are “in recovery” from an alcohol or drug problem yet only a scant emergent literature has begun to ask how they define “recovery” or explored whether there is heterogeneity among their definitions. Methods Secondary analysis of the What Is Recovery? online survey employed Latent Class Analysis (LCA) to identify typologies of study participants based on their actual endorsement of 39 recovery elements and to compare the composition of these typologies in terms of distinguishing personal characteristics. Results A 5-class solution provided the best fit and conceptual representation for the recovery definitions. Classes were labeled 12-Step Traditionalist (n=4912); 12-Step Enthusiast (n=2014); Secular (n=980); Self-Reliant (n=1040); and Atypical (n=382) based on patterns of endorsement of the recovery elements. Abstinence, spiritual, and social interaction elements differentiated the classes most (as did age and recovery duration but to a lesser extent). Although levels and patterns of endorsement to the elements varied by class, a rank-ordering of the top 10 elements indicated that four elements were endorsed by all five classes: being honest with myself, handling negative feelings without using, being able to enjoy life, and process of growth and development. Conclusions The results of the LCA demonstrate the diversity of meanings, and varying degrees of identification with, specific elements of recovery. As others have found, multiple constituents are invested in how recovery is defined and this has ramifications for professional, personal, and cultural processes related to how strategies to promote recovery are implemented. PMID:25630961

  13. LDRD 149045 final report distinguishing documents.

    SciTech Connect

    Mitchell, Scott A.

    2010-09-01

    This LDRD 149045 final report describes work that Sandians Scott A. Mitchell, Randall Laviolette, Shawn Martin, Warren Davis, Cindy Philips and Danny Dunlavy performed in 2010. Prof. Afra Zomorodian provided insight. This was a small late-start LDRD. Several other ongoing efforts were leveraged, including the Networks Grand Challenge LDRD, and the Computational Topology CSRF project, and the some of the leveraged work is described here. We proposed a sentence mining technique that exploited both the distribution and the order of parts-of-speech (POS) in sentences in English language documents. The ultimate goal was to be able to discover 'call-to-action' framing documents hidden within a corpus of mostly expository documents, even if the documents were all on the same topic and used the same vocabulary. Using POS was novel. We also took a novel approach to analyzing POS. We used the hypothesis that English follows a dynamical system and the POS are trajectories from one state to another. We analyzed the sequences of POS using support vector machines and the cycles of POS using computational homology. We discovered that the POS were a very weak signal and did not support our hypothesis well. Our original goal appeared to be unobtainable with our original approach. We turned our attention to study an aspect of a more traditional approach to distinguishing documents. Latent Dirichlet Allocation (LDA) turns documents into bags-of-words then into mixture-model points. A distance function is used to cluster groups of points to discover relatedness between documents. We performed a geometric and algebraic analysis of the most popular distance functions and made some significant and surprising discoveries, described in a separate technical report.

  14. Imaging transplanted stem cells in real time using an MRI dual-contrast method

    PubMed Central

    Ngen, Ethel J.; Wang, Lee; Kato, Yoshinori; Krishnamachary, Balaji; Zhu, Wenlian; Gandhi, Nishant; Smith, Barbara; Armour, Michael; Wong, John; Gabrielson, Kathleen; Artemov, Dmitri

    2015-01-01

    Stem cell therapies are currently being investigated for the repair of brain injuries. Although exogenous stem cell labelling with superparamagnetic iron oxide nanoparticles (SPIONs) prior to transplantation provides a means to noninvasively monitor stem cell transplantation by magnetic resonance imaging (MRI), monitoring cell death is still a challenge. Here, we investigate the feasibility of using an MRI dual-contrast technique to detect cell delivery, cell migration and cell death after stem cell transplantation. Human mesenchymal stem cells were dual labelled with SPIONs and gadolinium-based chelates (GdDTPA). The viability, proliferation rate, and differentiation potential of the labelled cells were then evaluated. The feasibility of this MRI technique to distinguish between live and dead cells was next evaluated using MRI phantoms, and in vivo using both immune-competent and immune-deficient mice, following the induction of brain injury in the mice. All results were validated with bioluminescence imaging. In live cells, a negative (T2/T2*) MRI contrast predominates, and is used to track cell delivery and cell migration. Upon cell death, a diffused positive (T1) MRI contrast is generated in the vicinity of the dead cells, and serves as an imaging marker for cell death. Ultimately, this technique could be used to manage stem cell therapies. PMID:26330231

  15. Magnetic Resonance Imaging (MRI) -- Head

    MedlinePLUS Videos and Cool Tools

    ... imaging methods. This exam does not use ionizing radiation and may require an injection of a contrast ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ...

  16. Acoustic variability and distinguishability among mouse ultrasound vocalizations

    NASA Astrophysics Data System (ADS)

    Liu, Robert C.; Miller, Kenneth D.; Merzenich, Michael M.; Schreiner, Christoph E.

    2003-12-01

    Auditory neurobiology has benefited significantly from ethological approaches using acoustic communication signals. Developing an ethological model in a genetically manipulable system such as the mouse would enhance the ability to investigate the processing, learning, and recognition of sounds. Characterizing the basic acoustic structure of mouse vocalizations would help lay a foundation for such a future study. Towards this goal, ultrasound vocalizations emitted by isolated mouse pups and pairs of adult males and females have been digitally recorded and examined. Previous work suggests that these calls may have communicative significance. An analysis of the natural variability in their spectral content, median frequency, duration, and repetition period reveals acoustic structure that could be used for recognizing the calls. Other parameters, like the rate of frequency modulation, may also be informative, but have not been examined. Pup isolation calls develop systematically between postnatal day 5 and 12 towards a more stereotyped vocalization-contracting from a wide range of values into narrower clusters of frequency and duration, and shifting from longer to shorter repetition periods. Most significantly, pup isolation and adult encounter calls fall into two distinct spectral and temporal categories, making it possible for a receiver to acoustically distinguish between them, and to potentially categorically perceive them along those dimensions.

  17. MRI-Guided Electrophysiology Intervention*

    PubMed Central

    Halperin, Henry R.; Kolandaivelu, Aravindan

    2010-01-01

    Catheter ablation is a first-line treatment for many cardiac arrhythmias and is generally performed under X-ray fluoroscopy guidance. However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with sub-optimal success rates and prolonged radiation exposure. Pre-procedure 3-D magnetic resonance imaging (MRI) has improved understanding of the anatomic basis of complex arrhythmias and is being used for planning and guidance of ablation procedures. A particular strength of MRI compared to other imaging modalities is the ability to visualize ablation lesions. Post-procedure MRI is now being applied to assess ablation lesion location and permanence with the goal of identifying factors leading to procedure success and failure. In the future, intra-procedure real-time MRI, together with the ability to image complex 3-D arrhythmogenic anatomy and target additional ablation to regions of incomplete lesion formation, may allow for more successful treatment of even complex arrhythmias without exposure to ionizing radiation. Development of clinical grade MRI-compatible electrophysiology devices is required to transition intra-procedure MRI from preclinical studies to more routine use in patients. PMID:23908787

  18. Quintuple-modality (SERS-MRI-CT-TPL-PTT) plasmonic nanoprobe for theranostics.

    PubMed

    Liu, Yang; Chang, Zheng; Yuan, Hsiangkuo; Fales, Andrew M; Vo-Dinh, Tuan

    2013-12-21

    A unique quintuple-modality theranostic nanoprobe (QMT) is developed with gold nanostars for surface-enhanced Raman scattering (SERS), magnetic resonance imaging (MRI), computed tomography (CT), two-photon luminescence (TPL) imaging and photothermal therapy (PTT). The synthesized gold nanostars were tagged with a SERS reporter and linked with an MRI contrast agent Gd(3+). In vitro experiments demonstrated the developed QMT nanoprobe to be a potential theranostic agent for future biomedical applications. PMID:24162005

  19. Magnetic resonance imaging (MRI) anatomy of the ovine lumbar spine.

    PubMed

    Nisolle, J F; Wang, X Q; Squélart, M; Hontoir, F; Kirschvink, N; Clegg, P; Vandeweerd, J M

    2014-06-01

    Although the ovine spine is a useful research model for intervertebral disc pathology and vertebral surgery, there is little peer-reviewed information regarding the MRI anatomy of the ovine spine. To describe the lumbar spine MRI anatomy, 10 lumbar segments of cadaver ewes were imaged by 1.5-Tesla MR. Sagittal and transverse sequences were performed in T1 and T2 weighting (T1W, T2W), and the images were compared to gross anatomic sagittal and transverse sections performed through frozen spines. MRI was able to define most anatomic structures of the ovine spine in a similar way as can be imaged in humans. In both T1W and T2W, the signals of ovine IVDs were similar to those observed in humans. Salient anatomic features were identified: (1) a 2- to 3-mm linear zone of hypersignal was noticed on both extremities of the vertebral body parallel to the vertebral plates in sagittal planes; (2) the tendon of the crura of the diaphragm appeared as a hypointense circular structure between hypaxial muscles and the aorta and caudal vena cava; (3) dorsal and ventral longitudinal ligaments and ligamentum flavum were poorly imaged; (4) no ilio-lumbar ligament was present; (5) the spinal cord ended between S1-S2 level, and the peripheral white matter and central grey matter were easily distinguished on T1W and T2W images. This study provides useful reference images to researchers working with ovine models. PMID:23668479

  20. In Vivo Molecular MRI Imaging of Prostate Cancer by Targeting PSMA with Polypeptide-Labeled Superparamagnetic Iron Oxide Nanoparticles

    PubMed Central

    Zhu, Yunkai; Sun, Ying; Chen, Yaqing; Liu, Weiyong; Jiang, Jun; Guan, Wenbin; Zhang, Zhongyang; Duan, Yourong

    2015-01-01

    The prostate specific membrane antigen (PSMA) is broadly overexpressed on prostate cancer (PCa) cell surfaces. In this study, we report the synthesis, characterization, in vitro binding assay, and in vivo magnetic resonance imaging (MRI) evaluation of PSMA targeting superparamagnetic iron oxide nanoparticles (SPIONs). PSMA-targeting polypeptide CQKHHNYLC was conjugated to SPIONs to form PSMA-targeting molecular MRI contrast agents. In vitro studies demonstrated specific uptake of polypeptide-SPIONs by PSMA expressing cells. In vivo MRI studies found that MRI signals in PSMA-expressing tumors could be specifically enhanced with polypeptide-SPION, and further Prussian blue staining showed heterogeneous deposition of SPIONs in the tumor tissues. Taken altogether, we have developed PSMA-targeting polypeptide-SPIONs that could specifically enhance MRI signal in tumor-bearing mice, which might provide a new strategy for the molecular imaging of PCa. PMID:25927579

  1. Conjugation to Biocompatible Dendrimers Increases Lanthanide T2 Relaxivity of Hydroxypyridinone (HOPO) Complexes for Magnetic Resonance Imaging (MRI).

    PubMed

    Klemm, Piper J; Floyd, William C; Andolina, Christopher M; Fréchet, Jean M J; Raymond, Kenneth N

    2012-04-01

    Magnetic resonance imaging (MRI) contrast agents represent a worldwide billion-dollar market annually. While T1 relaxivity enhancement contrast agents receive greater attention and a significantly larger market share, the commercial potential for T2 relaxivity enhancing contrast agents remains a viable diagnostic option due to their increased relaxivity at high field strengths. Improving the contrast and biocompatibility of T2 MRI probes may enable new diagnostic prospects for MRI. Paramagnetic lanthanides have the potential to decrease T1 and T2 proton relaxation times, but are not commercially used in MRI diagnostics as T2 agents. In this article, oxygen donor chelates (hydroxypyridinone, HOPO, and terephthalamide, TAM) of various lanthanides are demonstrated as biocompatible macromolecular dendrimer conjugates for the development of T2 MRI probes. These conjugates have relaxivities up to 374 mm(-1)s(-1) per dendrimer, high bioavailability, and low in vitro toxicity. PMID:23539072

  2. Conjugation to Biocompatible Dendrimers Increases Lanthanide T2 Relaxivity of Hydroxypyridinone (HOPO) Complexes for Magnetic Resonance Imaging (MRI)

    PubMed Central

    Klemm, Piper J.; Floyd, William C.; Andolina, Christopher M.; Fréchet, Jean M. J.; Raymond, Kenneth N.

    2013-01-01

    Magnetic resonance imaging (MRI) contrast agents represent a worldwide billion-dollar market annually. While T1 relaxivity enhancement contrast agents receive greater attention and a significantly larger market share, the commercial potential for T2 relaxivity enhancing contrast agents remains a viable diagnostic option due to their increased relaxivity at high field strengths. Improving the contrast and biocompatibility of T2 MRI probes may enable new diagnostic prospects for MRI. Paramagnetic lanthanides have the potential to decrease T1 and T2 proton relaxation times, but are not commercially used in MRI diagnostics as T2 agents. In this article, oxygen donor chelates (hydroxypyridinone, HOPO, and terephthalamide, TAM) of various lanthanides are demonstrated as biocompatible macromolecular dendrimer conjugates for the development of T2 MRI probes. These conjugates have relaxivities up to 374 mm?1s?1 per dendrimer, high bioavailability, and low in vitro toxicity. PMID:23539072

  3. Distinguishing the Forest from the Trees: Synthesizing IHRMP Research1

    E-print Network

    Distinguishing the Forest from the Trees: Synthesizing IHRMP Research1 Gregory B. Greenwood2 Protection, Sacra mento. such things as elevation, soil texture, vegetation, ownership, etc. Processes, both

  4. CT and MRI evaluation of cardiac complications in patients with hematologic diseases: a pictorial review.

    PubMed

    Kim, Tae Yun; Jung, Jung Im; Kim, Yoo Jin; Kim, Hwan Wook; Lee, Hae Giu

    2015-12-01

    Cardiac complications with hematologic diseases are not uncommon but it is difficult to diagnose, due to non-specific clinical symptoms. Prompt recognition of these potentially fatal complications by cardiac computed tomography (CT) or cardiac magnetic resonance imaging (MRI) may help to direct clinicians to specific treatments according to causes. Thrombosis is often related to central venous catheter use and is usually located at the catheter tip near the atrial wall. Differentiation of thrombosis from normal structure is possible with CT and, distinction of a thrombus from a tumor is possible on a delayed enhancement MRI with a long inversion time (500-600 ms). Granulocytic sarcoma of the heart is indicated by an infiltrative nature with involvement of whole layers of myocardium on CT and MRI. MRI with T2* mapping is useful in evaluating myocardial iron content in patients with hemochromatosis. Diffuse subendocardial enhancement is typically observed on delayed MRIs in patients with cardiac amyloidosis. T1 mapping is an emerging tool to diagnose amyloidosis. Myocardial abscess can occur due to an immunocompromised status. CT and MRI show loculated lesions with fluid density and concomitant rim-like contrast enhancement. Awareness of CT and MRI findings of cardiac complications of hematologic diseases can be helpful to physicians for clinical decision making and treatment. PMID:25651878

  5. Iron-Based Superparamagnetic Nanoparticle Contrast Agents for MRI of Infection and Inflammation

    PubMed Central

    Neuwelt, Alexander; Sidhu, Navneet; Hu, Chien-An A.; Mlady, Gary; Eberhardt, Steven C.; Sillerud, Laurel O.

    2015-01-01

    OBJECTIVE In this article, we summarize the progress to date on the use of superparamagnetic iron oxide nanoparticles (SPIONs) as contrast agents for MRI of inflammatory processes. CONCLUSION Phagocytosis by macrophages of injected SPIONs results in a prolonged shortening of both T2 and T2* leading to hypointensity of macrophage-infiltrated tissues in contrast-enhanced MR images. SPIONs as contrast agents are therefore useful for the in vivo MRI detection of macrophage infiltration, and there is substantial research and clinical interest in the use of SPION-based contrast agents for MRI of infection and inflammation. This technique has been used to identify active infection in patients with septic arthritis and osteomyelitis; importantly, the MRI signal intensity of the tissue has been found to return to its un-enhanced value on successful treatment of the infection. In SPION contrast-enhanced MRI of vascular inflammation, animal studies have shown decreased macrophage uptake in atherosclerotic plaques after treatment with statin drugs. Human studies have shown that both coronary and carotid plaques that take up SPIONs are more prone to rupture and that abdominal aneurysms with increased SPION uptake are more likely to grow. Studies of patients with multiple sclerosis suggest that MRI using SPIONs may have increased sensitivity over gadolinium for plaque detection. Finally, SPIONs have enabled the tracking and imaging of transplanted stem cells in a recipient host. PMID:25714316

  6. Segmentation precision of abdominal anatomy for MRI-based radiotherapy

    SciTech Connect

    Noel, Camille E.; Zhu, Fan; Lee, Andrew Y.; Yanle, Hu; Parikh, Parag J.

    2014-10-01

    The limited soft tissue visualization provided by computed tomography, the standard imaging modality for radiotherapy treatment planning and daily localization, has motivated studies on the use of magnetic resonance imaging (MRI) for better characterization of treatment sites, such as the prostate and head and neck. However, no studies have been conducted on MRI-based segmentation for the abdomen, a site that could greatly benefit from enhanced soft tissue targeting. We investigated the interobserver and intraobserver precision in segmentation of abdominal organs on MR images for treatment planning and localization. Manual segmentation of 8 abdominal organs was performed by 3 independent observers on MR images acquired from 14 healthy subjects. Observers repeated segmentation 4 separate times for each image set. Interobserver and intraobserver contouring precision was assessed by computing 3-dimensional overlap (Dice coefficient [DC]) and distance to agreement (Hausdorff distance [HD]) of segmented organs. The mean and standard deviation of intraobserver and interobserver DC and HD values were DC{sub intraobserver} = 0.89 ± 0.12, HD{sub intraobserver} = 3.6 mm ± 1.5, DC{sub interobserver} = 0.89 ± 0.15, and HD{sub interobserver} = 3.2 mm ± 1.4. Overall, metrics indicated good interobserver/intraobserver precision (mean DC > 0.7, mean HD < 4 mm). Results suggest that MRI offers good segmentation precision for abdominal sites. These findings support the utility of MRI for abdominal planning and localization, as emerging MRI technologies, techniques, and onboard imaging devices are beginning to enable MRI-based radiotherapy.

  7. Segmentation precision of abdominal anatomy for MRI-based radiotherapy.

    PubMed

    Noel, Camille E; Zhu, Fan; Lee, Andrew Y; Yanle, Hu; Parikh, Parag J

    2014-01-01

    The limited soft tissue visualization provided by computed tomography, the standard imaging modality for radiotherapy treatment planning and daily localization, has motivated studies on the use of magnetic resonance imaging (MRI) for better characterization of treatment sites, such as the prostate and head and neck. However, no studies have been conducted on MRI-based segmentation for the abdomen, a site that could greatly benefit from enhanced soft tissue targeting. We investigated the interobserver and intraobserver precision in segmentation of abdominal organs on MR images for treatment planning and localization. Manual segmentation of 8 abdominal organs was performed by 3 independent observers on MR images acquired from 14 healthy subjects. Observers repeated segmentation 4 separate times for each image set. Interobserver and intraobserver contouring precision was assessed by computing 3-dimensional overlap (Dice coefficient [DC]) and distance to agreement (Hausdorff distance [HD]) of segmented organs. The mean and standard deviation of intraobserver and interobserver DC and HD values were DC(intraobserver) = 0.89 ± 0.12, HD(intraobserver) = 3.6mm ± 1.5, DC(interobserver) = 0.89 ± 0.15, and HD(interobserver) = 3.2mm ± 1.4. Overall, metrics indicated good interobserver/intraobserver precision (mean DC > 0.7, mean HD < 4mm). Results suggest that MRI offers good segmentation precision for abdominal sites. These findings support the utility of MRI for abdominal planning and localization, as emerging MRI technologies, techniques, and onboard imaging devices are beginning to enable MRI-based radiotherapy. PMID:24726701

  8. MRI-based Preplanning Using CT and MRI Data Fusion in Patients With Cervical Cancer Treated With 3D-based Brachytherapy: Feasibility and Accuracy Study

    SciTech Connect

    Dolezel, Martin; First Faculty of Medicine, Charles University, Prague ; Odrazka, Karel; First Faculty of Medicine, Charles University, Prague ; Zizka, Jan; Vanasek, Jaroslav; Kohlova, Tereza; Kroulik, Tomas; Spitzer, Dusan; Ryska, Pavel; Tichy, Michal; Kostal, Milan; Jalcova, Lubica

    2012-09-01

    Purpose: Magnetic resonance imaging (MRI)-assisted radiation treatment planning enables enhanced target contouring. The purpose of this study is to analyze the feasibility and accuracy of computed tomography (CT) and MRI data fusion for MRI-based treatment planning in an institution where an MRI scanner is not available in the radiotherapy department. Methods and Materials: The registration inaccuracy of applicators and soft tissue was assessed in 42 applications with CT/MRI data fusion. The absolute positional difference of the center of the applicators was measured in four different planes from the top of the tandem to the cervix. Any inaccuracy of registration of soft tissue in relation to the position of applicators was determined and dose-volume parameters for MRI preplans and for CT/MRI fusion plans with or without target and organs at risk (OAR) adaptation were evaluated. Results: We performed 6,132 measurements in 42 CT/MRI image fusions. Median absolute difference of the center of tandem on CT and MRI was 1.1 mm. Median distance between the center of the right ovoid on CT and MRI was 1.7 and 1.9 mm in the laterolateral and anteroposterior direction, respectively. Corresponding values for the left ovoid were 1.6 and 1.8 mm. Rotation of applicators was 3.1 Degree-Sign . Median absolute difference in position of applicators in relation to soft tissue was 1.93, 1.50, 1.05, and 0.84 mm in the respective transverse planes, and 1.17, 1.28, 1.27, and 1.17 mm in selected angular directions. The dosimetric parameters for organs at risk on CT/MRI fusion plans without OAR adaptation were significantly impaired whereas the target coverage was not influenced. Planning without target adaptation led to overdosing of the target volume, especially high-risk clinical target volume - D{sub 90} 88.2 vs. 83.1 (p < 0.05). Conclusions: MRI-based preplanning with consecutive CT/MRI data fusion can be safe and feasible, with an acceptable inaccuracy of soft tissue registration.

  9. MRI characterization of cobalt dichloride-N-acetyl cysteine (C4) contrast agent marker for prostate brachytherapy

    NASA Astrophysics Data System (ADS)

    Lim, Tze Yee; Stafford, R. Jason; Kudchadker, Rajat J.; Sankaranarayanapillai, Madhuri; Ibbott, Geoffrey; Rao, Arvind; Martirosyan, Karen S.; Frank, Steven J.

    2014-05-01

    Brachytherapy, a radiotherapy technique for treating prostate cancer, involves the implantation of numerous radioactive seeds into the prostate. While the implanted seeds can be easily identified on a computed tomography image, distinguishing the prostate and surrounding soft tissues is not as straightforward. Magnetic resonance imaging (MRI) offers superior anatomical delineation, but the seeds appear as dark voids and are difficult to identify, thus creating a conundrum. Cobalt dichloride-N-acetyl-cysteine (C4) has previously been shown to be promising as an encapsulated contrast agent marker. We performed spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measurements of C4 solutions with varying cobalt dichloride concentrations to determine the corresponding relaxivities, r1 and r2. These relaxation parameters were investigated at different field strengths, temperatures and orientations. T1 measurements obtained at 1.5 and 3.0 T, as well as at room and body temperature, showed that r1 is field-independent and temperature-independent. Conversely, the T2 values at 3.0 T were shorter than at 1.5 T, while the T2 values at body temperature were slightly higher than at room temperature. By examining the relaxivities with the C4 vials aligned in three different planes, we found no orientation-dependence. With these relaxation characteristics, we aim to develop pulse sequences that will enhance the C4 signal against prostatic stroma. Ultimately, the use of C4 as a positive contrast agent marker will encourage the use of MRI to obtain an accurate representation of the radiation dose delivered to the prostate and surrounding normal anatomical structures.

  10. Fusion of Delayed-enhancement MR Imaging and Contrast-enhanced MR Angiography to Visualize Radiofrequency Ablation Scar on the Pulmonary Vein.

    PubMed

    Shigenaga, Yutaka; Kiuchi, Kunihiko; Ikeuchi, Kazushi; Ikeda, Takayuki; Okajima, Katsunori; Yasaka, Yoshinori; Kawai, Hiroya

    2015-11-13

    Delayed-enhancement magnetic resonance imaging (DE-MRI) is reported to detect the radiofrequency (RF) ablation scar of pulmonary vein isolation. However, the precise localization of RF scar is difficult to recognize due to the poor anatomical information of the 3-dimensionally reconstructed DE-MRI. We report 2 cases in which fusion of DE-MRI and contrast-enhanced MR angiography facilitated the identification of RF scar, and we detail our fusion method. PMID:26104077

  11. MRI Tracking of Graft Survival in the Infarcted Heart: Iron Oxide Particles vs. Ferritin Overexpression Approach

    PubMed Central

    Naumova, Anna V.; Balu, Niranjan; Yarnykh, Vasily L.; Reinecke, Hans; Murry, Charles E.; Yuan, Chun

    2014-01-01

    The main objective of cell therapy is regeneration of damaged tissues. To distinguish graft from host tissue by MRI, a paramagnetic label must be introduced to cells prior to transplantation. The paramagnetic label can be either exogenous iron oxide nanoparticles or a genetic overexpression of ferritin, an endogenous iron storage protein. The purpose of this work was to compare efficacy of these two methods for MRI evaluation of engrafted cell survival in the infarcted mouse heart. Mouse skeletal myoblasts were labeled either by co-cultivation with iron oxide particles or by engineering them to overexpress ferritin. Along with live cell transplantation, two other groups of mice were injected with dead labeled cells. Both particle-labeled and ferritin-tagged grafts were detected as areas of MRI signal hypointensity in the left ventricle of the mouse heart using T2*-weighted sequences, although the signal attenuation decreased with ferritin tagging. Importantly, live cells could not be distinguished from dead cells when labeled with iron oxide particles, whereas the ferritin-tagging was detected only in live grafts, thereby allowing identification of viable grafts using MRI. Thus, iron oxide particles can provide information about initial cell injection success but cannot assess graft viability. On the other hand, genetically based cell-tagging, such as ferritin overexpression, despite having lower signal intensity in comparison with iron oxide particles, is able to identify live transplanted cells. PMID:24685664

  12. A New Statistical Distinguisher for the Shrinking Generator

    E-print Network

    International Association for Cryptologic Research (IACR)

    A New Statistical Distinguisher for the Shrinking Generator Jovan Dj. Goli#19;c and Renato Menicocci Abstract The shrinking generator is a well-known keystream generator composed of two linear for keystream generators are algorithms whose objective is to distinguish the keystream sequence from a purely

  13. Distinguishability of Biological Material Using Ultraviolet Multi-Spectral Fluorescence

    SciTech Connect

    Gray, P.C.; Heinen, R.J.; Rigdon, L.D.; Rosenthal, S.E.; Shokair, I.R.; Siragusa, G.R.; Tisone, G.C.; Wagner, J.S.

    1998-10-14

    Recent interest in the detection and analysis of biological samples by spectroscopic methods has led to questions concerning the degree of distinguishability and biological variability of the ultraviolet (W) fluorescent spectra from such complex samples. We show that the degree of distinguishability of such spectra is readily determined numerically.

  14. Liberating the Publications of a Distinguished Scholar: A Pilot Project

    ERIC Educational Resources Information Center

    Kelly, Julie

    2014-01-01

    Many distinguished scholars published the primary corpus of their work before the advent of online journals, which makes it more challenging to access. Upon being approached by a distinguished Emeritus Professor seeking advice about getting his work posted online, librarians at the University of Minnesota worked to gain copyright permissions to…

  15. Good is Not Good Enough Deriving Optimal Distinguishers

    E-print Network

    International Association for Cryptologic Research (IACR)

    . Different choices of Annelie Heuser is a Google European fellow in the field of privacy and is partially. Mangard et al. [12] argue that some distinguishers achieve success performance all the more similar of success probability between a class of selected distinguishers (notably maximum likelihood and correlation

  16. Charles L. Brewer Award for Distinguished Teaching of Psychology

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    The American Psychological Foundation (APF) Charles L. Brewer Distinguished Teaching of Psychology Award recognizes an outstanding career contribution to the teaching of psychology. The 2009 recipient of the Distinguished Teaching Award is William Buskist. Dorothy W. Cantor, president of the APF, will present the APF Teaching Award at the 117th…

  17. Richard D. James Distinguished McKnight University Professor

    E-print Network

    James, Ashley

    Richard D. James Distinguished McKnight University Professor Department of Aerospace Engineering and Mechanics 107 Akerman Hall, 110 Union Street S.E. University of Minnesota Minneapolis, MN 55455 612) of Ref. [34] 1991 George Taylor Distinguished Research Award, Institute of Technology (One award given

  18. Distinguishing Samples of Spoken Korean from Rhythmic and Regional Competitors.

    ERIC Educational Resources Information Center

    Bond, Z. S.; Stockmal, Verna

    2002-01-01

    Examined characteristics of the acoustic signature of languages in connection with identification of the target language, Korean. In one experiment, listeners were asked to distinguish spoken samples of Korean from competitor languages sharing syllable based rhythm. In another, listeners attempted to distinguish Korean from languages spoken in the…

  19. Learning Comprehensible Relational Features to Distinguish Subfossil Decapod Crustacean Dactyls

    E-print Network

    Goadrich, Mark

    Learning Comprehensible Relational Features to Distinguish Subfossil Decapod Crustacean Dactyls Programming to a new domain in- volving decapod crustacean claws. We nd that we can distinguish dactyl shapes Description Because decapod crustacean claws are potentially a ected by numerous selective agents

  20. NMR and MRI apparatus and method

    DOEpatents

    Clarke, John; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Myers, Whittier; McDermott, Robert; ten Haken, Bernard; Pines, Alexander; Trabesinger, Andreas

    2007-03-06

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. Additional signal to noise benefits are obtained by use of a low noise polarization coil, comprising litz wire or superconducting materials. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  1. Malignant retroperitoneal fibrosis: MRI characteristics in 50 patients.

    PubMed

    Mirault, Tristan; Lambert, Marc; Puech, Philippe; Argatu, Danielle; Renaud, Armelle; Duhamel, Alain; Glovacki, François; Villers, Arnaud; Hachulla, Eric; Biserte, Jacques; Hatron, Pierre-Yves; Lemaitre, Laurent

    2012-09-01

    We analyzed magnetic resonance imaging (MRI) morphologic patterns of retroperitoneal fibrosis (RF) to identify those able to distinguish malignant RF (mRF) from idiopathic RF (iRF). This retrospective study concerned 50 consecutive patients with MRI-based RF diagnoses, 35 of whom also had histologically proven RF. Previous radiotherapy, abdominal or pelvic surgery or infection during the preceding 6 months, vascular aneurysm (aorta or iliac artery), presence of retroperitoneal multiple nodular masses, or enlarged lymph nodes with a diameter >15 mm constituted exclusion criteria. Patients with mRF differed from those with iRF by age, smoking habits, and follow-up duration but not by clinical manifestations, inflammatory syndrome, or renal insufficiency. MRI-documented mRF extension along the aorta, from above the renal arteries to below the aortic bifurcation, was more frequent than iRF (47% vs. 0%; p = 0.001) but less frequent between the renal arteries and the aortic bifurcation (18% vs. 50%; p = 0.04); mRF extension behind the aorta was wider than iRF (5.0 vs. 2.5 mm; p = 0.03). Neither urinary tract nor vessel involvement differed. Medial ureteral attraction was significantly less frequent in mRF than iRF (24% vs. 83%; p < 0.001), according to univariate and multivariate analyses. An algorithm based on the most discriminant criteria (RF extending from above the renal arteries to below the aortic bifurcation and the absence of medial ureteral attraction) for mRF diagnosis had 82% sensitivity and 83% specificity. When applied to the 15 iRF patients without histologic data, specificity was 73%. This mRF decision tree, consisting of the 2 most discriminant MRI criteria, could be used as a supplementary argument to support RF biopsy. PMID:22932788

  2. Estimating Motion From MRI Data

    PubMed Central

    OZTURK, CENGIZHAN; DERBYSHIRE, J. ANDREW; MCVEIGH, ELLIOT R.

    2007-01-01

    Invited Paper Magnetic resonance imaging (MRI) is an ideal imaging modality to measure blood flow and tissue motion. It provides excellent contrast between soft tissues, and images can be acquired at positions and orientations freely defined by the user. From a temporal sequence of MR images, boundaries and edges of tissues can be tracked by image processing techniques. Additionally, MRI permits the source of the image signal to be manipulated. For example, temporary magnetic tags displaying a pattern of variable brightness may be placed in the object using MR saturation techniques, giving the user a known pattern to detect for motion tracking. The MRI signal is a modulated complex quantity, being derived from a rotating magnetic field in the form of an induced current. Well-defined patterns can also be introduced into the phase of the magnetization, and could be thought of as generalized tags. If the phase of each pixel is preserved during image reconstruction, relative phase shifts can be used to directly encode displacement, velocity and acceleration. New methods for modeling motion fields from MRI have now found application in cardiovascular and other soft tissue imaging. In this review, we shall describe the methods used for encoding, imaging, and modeling motion fields with MRI. PMID:18958181

  3. Albert Einstein Distinguished Educators Fellowship Act of 1994. Report To Accompany S. 2104. 103D Congress, 2d Session, Senate.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Committee on Energy and Natural Resources.

    This document contains the text of the "Albert Einstein Distinguished Educators Fellowship Act of 1994" (S. 2104) along with related analysis. The bill establishes a Department of Energy (DOE) fellowship program for math and science teachers that provides them opportunities to work at DOE labs in order to enhance coordination and communication…

  4. Bringing memory fMRI to the clinic: comparison of seven memory fMRI protocols in temporal lobe epilepsy.

    PubMed

    Towgood, Karren; Barker, Gareth J; Caceres, Alejandro; Crum, William R; Elwes, Robert D C; Costafreda, Sergi G; Mehta, Mitul A; Morris, Robin G; von Oertzen, Tim J; Richardson, Mark P

    2015-04-01

    fMRI is increasingly implemented in the clinic to assess memory function. There are multiple approaches to memory fMRI, but limited data on advantages and reliability of different methods. Here, we compared effect size, activation lateralisation, and between-sessions reliability of seven memory fMRI protocols: Hometown Walking (block design), Scene encoding (block design and event-related design), Picture encoding (block and event-related), and Word encoding (block and event-related). All protocols were performed on three occasions in 16 patients with temporal lobe epilepsy (TLE). Group T-maps showed activity bilaterally in medial temporal lobe for all protocols. Using ANOVA, there was an interaction between hemisphere and seizure-onset lateralisation (P?=?0.009) and between hemisphere, protocol and seizure-onset lateralisation (P?=?0.002), showing that the distribution of memory-related activity between left and right temporal lobes differed between protocols and between patients with left-onset and right-onset seizures. Using voxelwise intraclass Correlation Coefficient, between-sessions reliability was best for Hometown and Scenes (block and event). The between-sessions spatial overlap of activated voxels was also greatest for Hometown and Scenes. Lateralisation of activity between hemispheres was most reliable for Scenes (block and event) and Words (event). Using receiver operating characteristic analysis to explore the ability of each fMRI protocol to classify patients as left-onset or right-onset TLE, only the Words (event) protocol achieved a significantly above-chance classification of patients at all three sessions. We conclude that Words (event) protocol shows the best combination of between-sessions reliability of the distribution of activity between hemispheres and reliable ability to distinguish between left-onset and right-onset patients. PMID:25727386

  5. An MRI-compatible hand sensory vibrotactile system.

    PubMed

    Wang, Fa; Lakshminarayanan, Kishor; Slota, Gregory P; Seo, Na Jin; Webster, John G

    2015-01-01

    Recently, the application of vibrotactile noise to the wrist or back of the hand has been shown to enhance fingertip tactile sensory perception (Enders et al 2013), supporting the potential for an assistive device worn at the wrist, that generates minute vibrations to help the elderly or patients with sensory deficit. However, knowledge regarding the detailed physiological mechanism behind this sensory improvement in the central nervous system, especially in the human brain, is limited, hindering progress in development and use of such assistive devices. To enable investigation of the impact of vibrotactile noise on sensorimotor brain activity in humans, a magnetic resonance imaging (MRI)-compatible vibrotactile system was developed to provide vibrotactile noise during an MRI of the brain. The vibrotactile system utilizes a remote (outside the MR room) signal amplifier which provides a voltage from -40 to +40?V to drive a 12?mm diameter piezoelectric vibrator (inside the MR room). It is portable and is found to be MRI-compatible which enables its use for neurologic investigation with MRI. The system was also found to induce an improvement in fingertip tactile sensation, consistent with the previous study. PMID:25501948

  6. Frequency-Offset Cartesian Feedback for MRI Power Amplifier Linearization

    PubMed Central

    Zanchi, Marta Gaia; Stang, Pascal; Kerr, Adam; Pauly, John Mark; Scott, Greig Cameron

    2011-01-01

    High-quality magnetic resonance imaging (MRI) requires precise control of the transmit radio-frequency field. In parallel excitation applications such as transmit SENSE, high RF power linearity is essential to cancel aliased excitations. In widely-employed class AB power amplifiers, gain compression, cross-over distortion, memory effects, and thermal drift all distort the RF field modulation and can degrade image quality. Cartesian feedback (CF) linearization can mitigate these effects in MRI, if the quadrature mismatch and DC offset imperfections inherent in the architecture can be minimized. In this paper, we present a modified Cartesian feedback technique called “frequency-offset Cartesian feedback” (FOCF) that significantly reduces these problems. In the FOCF architecture, the feedback control is performed at a low intermediate frequency rather than DC, so that quadrature ghosts and DC errors are shifted outside the control bandwidth. FOCF linearization is demonstrated with a variety of typical MRI pulses. Simulation of the magnetization obtained with the Bloch equation demonstrates that high-fidelity RF reproduction can be obtained even with inexpensive class AB amplifiers. Finally, the enhanced RF fidelity of FOCF over CF is demonstrated with actual images obtained in a 1.5 T MRI system. PMID:20959264

  7. REVIEW ARTICLE Multimodal MRI of Experimental Stroke

    E-print Network

    Duong, Timothy Q.

    REVIEW ARTICLE Multimodal MRI of Experimental Stroke Timothy Q. Duong Received: 30 October 2011 and application of multimodal MRI and image analysis techni- ques to study ischemic tissue at risk in experimental

  8. Magnetic Resonance Imaging (MRI): Lumbar Spine

    MedlinePLUS

    ... Kids Deal With Bullies Pregnant? What to Expect Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth > Parents > Doctors & Hospitals > Medical Tests & Exams > Magnetic Resonance Imaging (MRI): Lumbar Spine Print A A ...

  9. Creating a Pseudo-CT from MRI for MRI-only based Radiation

    E-print Network

    MRI images. Creating a pseudo-CT from MRI would eliminate the need for a real CT scan and thus facilitate an MRI-only work ow in the radiation therapy planning process. The use of GMR for pseudo-CT. CT head scans were also acquired using a standard protocol. A registration of the CT and MRI image

  10. Distinguishing bias from sensitivity effects in multialternative detection tasks

    PubMed Central

    Sridharan, Devarajan; Steinmetz, Nicholas A.; Moore, Tirin; Knudsen, Eric I.

    2014-01-01

    Studies investigating the neural bases of cognitive phenomena increasingly employ multialternative detection tasks that seek to measure the ability to detect a target stimulus or changes in some target feature (e.g., orientation or direction of motion) that could occur at one of many locations. In such tasks, it is essential to distinguish the behavioral and neural correlates of enhanced perceptual sensitivity from those of increased bias for a particular location or choice (choice bias). However, making such a distinction is not possible with established approaches. We present a new signal detection model that decouples the behavioral effects of choice bias from those of perceptual sensitivity in multialternative (change) detection tasks. By formulating the perceptual decision in a multidimensional decision space, our model quantifies the respective contributions of bias and sensitivity to multialternative behavioral choices. With a combination of analytical and numerical approaches, we demonstrate an optimal, one-to-one mapping between model parameters and choice probabilities even for tasks involving arbitrarily large numbers of alternatives. We validated the model with published data from two ternary choice experiments: a target-detection experiment and a length-discrimination experiment. The results of this validation provided novel insights into perceptual processes (sensory noise and competitive interactions) that can accurately and parsimoniously account for observers' behavior in each task. The model will find important application in identifying and interpreting the effects of behavioral manipulations (e.g., cueing attention) or neural perturbations (e.g., stimulation or inactivation) in a variety of multialternative tasks of perception, attention, and decision-making. PMID:25146574

  11. Chlorotoxin-modified macromolecular contrast agent for MRI tumor diagnosis.

    PubMed

    Huang, Rongqin; Han, Liang; Li, Jianfeng; Liu, Shuhuan; Shao, Kun; Kuang, Yuyang; Hu, Xing; Wang, Xuxia; Lei, Hao; Jiang, Chen

    2011-08-01

    Clinical diagnosis of cancers using magnetic resonance imaging (MRI) is highly dependent on contrast agents, especially for brain tumors which contain blood-brain barrier (BBB) at the early stage. However, currently mostly used low molecular weight contrast agents such as Gd-DTPA suffer from rapid renal clearance, non-specificity, and low contrast efficiency. The aim of this paper is to investigate the potential of a macromolecular MRI contrast agent based on dendrigraft poly-l-lysines (DGLs), using chlorotoxin (CTX) as a tumor-specific ligand. The contrast agent using CTX-modified conjugate as the main scaffold and Gd-DTPA as the payload was successfully synthesized. The results of fluorescent microscopy showed that the modification of CTX could markedly enhance the cellular uptake in C6 glioma and liver tumor cell lines, but not in normal cell line. Significantly increased accumulation of CTX-modified conjugate within glioma and liver tumor was further demonstrated in tumor-bearing nude mice using in vivo imaging system. The MRI results showed that the signal enhancement of mice treated with CTX-modified contrast reached peak level at 5 min for both glioma and liver tumor, 144.97% ± 19.54% and 158.69% ± 12.41%, respectively, significantly higher than that of unmodified counterpart and commercial control. And most importantly, the signal enhancement of CTX-modified contrast agent maintained much longer compared to that of controls, which might be useful for more exact diagnosis for tumors. CTX-modified dendrimer-based conjugate might be applied as an efficient MRI contrast agent for targeted and accurate tumor diagnosis. This finding is especially important for tumors such as brain glioma which is known hard to be diagnosed due to the presence of BBB. PMID:21531455

  12. cMRI-BED: A novel informatics framework for cardiac MRI biomarker extraction and discovery applied to pediatric cardiomyopathy classification

    PubMed Central

    2015-01-01

    Background Pediatric cardiomyopathies are a rare, yet heterogeneous group of pathologies of the myocardium that are routinely examined clinically using Cardiovascular Magnetic Resonance Imaging (cMRI). This gold standard powerful non-invasive tool yields high resolution temporal images that characterize myocardial tissue. The complexities associated with the annotation of images and extraction of markers, necessitate the development of efficient workflows to acquire, manage and transform this data into actionable knowledge for patient care to reduce mortality and morbidity. Methods We develop and test a novel informatics framework called cMRI-BED for biomarker extraction and discovery from such complex pediatric cMRI data that includes the use of a suite of tools for image processing, marker extraction and predictive modeling. We applied our workflow to obtain and analyze a dataset of 83 de-identified cases and controls containing cMRI-derived biomarkers for classifying positive versus negative findings of cardiomyopathy in children. Bayesian rule learning (BRL) methods were applied to derive understandable models in the form of propositional rules with posterior probabilities pertaining to their validity. Popular machine learning methods in the WEKA data mining toolkit were applied using default parameters to assess cross-validation performance of this dataset using accuracy and percentage area under ROC curve (AUC) measures. Results The best 10-fold cross validation predictive performance obtained on this cMRI-derived biomarker dataset was 80.72% accuracy and 79.6% AUC by a BRL decision tree model, which is promising from this type of rare data. Moreover, we were able to verify that mycocardial delayed enhancement (MDE) status, which is known to be an important qualitative factor in the classification of cardiomyopathies, is picked up by our rule models as an important variable for prediction. Conclusions Preliminary results show the feasibility of our framework for processing such data while also yielding actionable predictive classification rules that can augment knowledge conveyed in cardiac radiology outcome reports. Interactions between MDE status and other cMRI parameters that are depicted in our rules warrant further investigation and validation. Predictive rules learned from cMRI data to classify positive and negative findings of cardiomyopathy can enhance scientific understanding of the underlying interactions among imaging-derived parameters. PMID:26329721

  13. Feasibility study on energy prediction of microwave ablation upon uterine adenomyosis and leiomyomas by MRI

    PubMed Central

    Xia, M; Zhi-yu, H; Jian-ming, C; Hong-yu, Z; Rui-fang, X; Yu, Y; Yan-li, H; Bao-wei, D

    2014-01-01

    Objective: To evaluate the feasibility of energy prediction of percutaneous microwave ablation (PMWA) upon uterine leiomyomas and adenomyosis by MRI. Methods: 63 patients (49 patients with 49 uterine leiomyomas and 14 patients with adenomyosis) who underwent ultrasound-guided PMWA treatment were studied during the period from June 2011 to December 2012. Before PMWA, contrast-enhanced MRI (ceMRI) was performed for all of the patients. Based on the signal intensity (SI) of T2 weighted MRI, uterine leiomyomas were classified as hypointense, isointense and hyperintense. During ablation, the output energy of the microwave was set at 50?W, and T11a microwave antennas were used. ceMRI was performed within 7 days after PMWA treatment. Non-perfused volume and energy required per unit volume were analysed statistically. Results: When unit volume of lesions was ablated, uterine adenomyosis needed more energy than did uterine leiomyomas, and hyperintense uterine leiomyomas needed more energy than did hypointense pattern. Conclusions: MRI SI of uterine leiomyomas and uterine adenomyosis can be used to predict PMWA energy. Advances in knowledge: The conclusions indicate that MRI SI can be used to perform pre-treatment planning, which will make the treatment more precise. PMID:24947033

  14. MRI-guided gene therapy Xiaoming Yanga

    E-print Network

    Atalar, Ergin

    Minireview MRI-guided gene therapy Xiaoming Yanga , Ergin Atalara,b,* a Department of Radiology gene expression. This review summarizes the current status of MRI- guided gene therapy. Ó 2006 resonance imaging; MRI-guided therapy; Gene therapy 1. Introduction Gene therapy is an exciting frontier

  15. MRI Grant Program: Expert Tips & Tricks

    E-print Network

    Alpay, S. Pamir

    MRI Grant Program: Expert Tips & Tricks to Nab Expensive Instrumentation WHITE PAPER Sponsored by: #12;White Paper: MRI Grant Program: Expert Tips & Tricks to Nab Expensive Instrumentation Principal Investigators Association | www.principalinvestigators.org 2 White Paper -- "MRI Grant Program: Expert Tips

  16. Cervical Spine MRI in Abused Infants.

    ERIC Educational Resources Information Center

    Feldman, Kenneth W.; And Others

    1997-01-01

    This study attempted to use cervical spine magnetic resonance imaging (MRI) to detect cord injury in 12 dead children with head injury from child abuse. Eighty percent of children autopsied had small cervical spine hemorrhages; MRI did not identify them and did not identify cord injury in any child studied, indicating that MRI scans are probably…

  17. An Overview of Magnetic Resonance Imaging (MRI)

    E-print Network

    Heller, Barbara

    An Overview of Magnetic Resonance Imaging (MRI) Academic Resource Center #12;Table of Contents imaging technique that records changing magnetic fields · Also called Nuclear Magnetic Resonance (NMR · What is MRI? · General · MRI Machine · Who is it for? · How does it work? · Magnetization vector

  18. JOB OPENINGS MRI technical developments and applications

    E-print Network

    Duong, Timothy Q.

    : Projects: Successful applicants will work on: 1) MRI pulse sequence programming or hardware (Siemens, in pulse-sequence development, Bruker or Siemens scanners, OR 2) Expertise in stroke, TBI and/or retinalcm Pharmascan 4) MRI: 3T/90cm whole-body Siemens TIM Trio 5) MRI: 3T/90cm whole-body Siemens TIM Trio

  19. Belief in a Just What? Demystifying Just World Beliefs by Distinguishing Sources of Justice

    PubMed Central

    Stroebe, Katherine; Postmes, Tom; Täuber, Susanne; Stegeman, Alwin; John, Melissa-Sue

    2015-01-01

    People’s Belief in a Just World (BJW) plays an important role in coping with misfortune and unfairness. This paper demonstrates that understanding of the BJW concept, and its consequences for behavior, is enhanced if we specify what (or who) the source of justice might be. We introduce a new scale, the 5-Dimensional Belief in a Just Treatment Scale (BJT5), which distinguishes five causal dimensions of BJW (God, Nature, Other People, Self, Chance). We confirm the 5-factor structure of the BJT5. We then address whether the BJW should be considered a uni- and/or multi-dimensional construct and find support for our multi-dimensional approach. Finally, we demonstrate convergent and discriminant validity with respect to important correlates of BJW as well as action in response to important negative life events and societal attitudes. This work illustrates the importance of distinguishing causal dimensions with regard to who distributes justice. PMID:25803025

  20. [Basics of MRI technique and MRI image interpretation].

    PubMed

    Imhof, H; Rand, T; Trattnig, S; Kramer, J

    1994-09-01

    Today magnetic resonance imaging (MRI) is an important routine diagnostic tool in orthopaedics. It is based on the nuclear magnetic resonance phenomenon: "free" hydrogen atoms (mainly from water) become field-parallel in a strong outer magnetic field. They reach a higher energy level by application of an additional electromagnetic field. After shutdown of this outer field the atoms send out electromagnetic waves (radiowaves), representing the MR signal. Different amounts of "free" water result in various image characteristics. Typically, a higher tissue water content is represented by high MR signals, e.g. in blastomas, inflammations and degenerative changes. Waterless structures such as calcified or fibrous tissues, tendons and ligaments show low MR signals. Fatty structures have high signals; proteins dissolved in "free" water change the water signal dramatically. Besides these basic parameters, para-, ferro- and super-paramagnetic materials--ether naturally present in the human body, such as methemoglobin, or artificially introduced, such as MR contrast media--and flow are responsible for different grey shades in MRI. MRI is not associated with ionizing radiation and allows imaging in all planes without changing the patient's position. Disadvantages of MRI are high costs and low availability. Future technical developments will result in shorter imaging times and broadening of the application spectrum, leading towards "MR fluoroscopy" and MR interventions. PMID:7970689

  1. Iron-based superparamagnetic nanoparticle contrast agents for MRI of infection and inflammation.

    PubMed

    Neuwelt, Alexander; Sidhu, Navneet; Hu, Chien-An A; Mlady, Gary; Eberhardt, Steven C; Sillerud, Laurel O

    2015-03-01

    OBJECTIVE. In this article, we summarize the progress to date on the use of superparamagnetic iron oxide nanoparticles (SPIONs) as contrast agents for MRI of inflammatory processes. CONCLUSION. Phagocytosis by macrophages of injected SPIONs results in a prolonged shortening of both T2 and T2* leading to hypointensity of macrophage-infiltrated tissues in contrast-enhanced MR images. SPIONs as contrast agents are therefore useful for the in vivo MRI detection of macrophage infiltration, and there is substantial research and clinical interest in the use of SPION-based contrast agents for MRI of infection and inflammation. This technique has been used to identify active infection in patients with septic arthritis and osteomyelitis; importantly, the MRI signal intensity of the tissue has been found to return to its unenhanced value on successful treatment of the infection. In SPION contrast-enhanced MRI of vascular inflammation, animal studies have shown decreased macrophage uptake in atherosclerotic plaques after treatment with statin drugs. Human studies have shown that both coronary and carotid plaques that take up SPIONs are more prone to rupture and that abdominal aneurysms with increased SPION uptake are more likely to grow. Studies of patients with multiple sclerosis suggest that MRI using SPIONs may have increased sensitivity over gadolinium for plaque detection. Finally, SPIONs have enabled the tracking and imaging of transplanted stem cells in a recipient host. PMID:25714316

  2. Distributed hippocampal patterns that discriminate reward context are associated with enhanced associative binding.

    PubMed

    Wolosin, Sasha M; Zeithamova, Dagmar; Preston, Alison R

    2013-11-01

    Recent research indicates that reward-based motivation impacts medial temporal lobe (MTL) encoding processes, leading to enhanced memory for rewarded events. In particular, previous functional magnetic resonance imaging (fMRI) studies of motivated learning have shown that MTL activation is greater for highly rewarded events, with the degree of reward-related activation enhancement tracking the corresponding behavioral memory advantage. These studies, however, do not directly address leading theoretical perspectives that propose such reward-based enhancements in MTL encoding activation reflect enhanced discrimination of the motivational context of specific events. In this study, a high-value or low-value monetary cue preceded a pair of objects, indicating the future reward for successfully remembering the pair. Using representational similarity analysis and high-resolution fMRI, we show that MTL activation patterns are more similar for encoding trials preceded by the same versus different reward cues, indicating a distributed code in this region that distinguishes between motivational contexts. Moreover, we show that activation patterns in hippocampus and parahippocampal cortex (PHc) that differentiate reward conditions during anticipatory cues and object pairs relate to successful associative memory. Additionally, the degree to which patterns differentiate reward contexts in dentate gyrus/CA2,3 and PHc is related to individual differences in reward modulation of memory. Collectively, these findings suggest that distributed activation patterns in the human hippocampus and PHc reflect the rewards associated with individual events. Furthermore, we show that these activation patterns-which discriminate between reward conditions--may influence memory through the incorporation of information about motivational contexts into stored memory representations. PMID:23834024

  3. Enhancement of magnetic resonance imaging with metasurfaces

    E-print Network

    Slobozhanyuk, A P; Raaijmakers, A J E; Berg, C A T van den; Kozachenko, A V; Dubrovina, I A; Melchakova, I V; Kivshar, Yu S; Belov, P A

    2015-01-01

    Magnetic resonance imaging (MRI) is the cornerstone technique for diagnostic medicine, biology, and neuroscience. This imaging method is highly innovative, noninvasive and its impact continues to grow. It can be used for measuring changes in the brain after enhanced neural activity, detecting early cancerous cells in tissue, as well as for imaging nanoscale biological structures, and controlling fluid dynamics, and it can be beneficial for cardiovascular imaging. The MRI performance is characterized by a signal-to-noise ratio, however the spatial resolution and image contrast depend strongly on the scanner design. Here, we reveal how to exploit effectively the unique properties of metasurfaces for the substantial improvement of MRI efficiency. We employ a metasurface created by an array of wires placed inside the MRI scanner under an object, and demonstrate a giant enhancement of the magnetic field by means of subwavelength near-field manipulation with the metasurface, thus strongly increasing the scanner sen...

  4. Predictors of neurodevelopmental outcome for preterm infants with brain injury: MRI, medical and environmental factors

    PubMed Central

    Badr, Lina Kurdahi; Bookheimer, Susan; Purdy, Isabell; Deeb, Mary

    2009-01-01

    This multi-center correlational prospective study examined early neonatal predictors of neurodevelopment in 59 premature infants (mean birth weight=1713.8±1242.5 g; mean gestational age=31.2±3.6 weeks) suspected to have sustained brain injury at birth. The mental and motor development of the infants selected from five university-affiliated hospitals was assessed at baseline (59 infants), 12 (55 infants), and 18 months (46 infants) using Bayley II scales. Factors correlating with Bayley II scores at 12 and 18 months included head circumference, results of neurological and magnetic resonance imaging (MRI) examination at baseline, environmental factors such as mother–infant interactions and levels of parental stress, and infant medical factors such as Apgar scores at 5 min and length of hospital stay. Multiple regression analyses distinguished the most significant predictors of mental and motor development. The best predictors of mental and motor development at 18 months were head circumference, neurological examinations, and MRI results. These findings suggest that in infants suspected of brain injury at birth, neurological assessments and head circumference measurements are just as predictive of developmental outcome at 18 months as MRI, and this is especially relevant in developing countries or other locations where MRI is not possible. The presence of this information may offer the potential of early tailored interventions to improve the mental and motor development of children in developing countries or other facilities where MRI is unavailable. PMID:19141366

  5. MRI of the lung gas-space at very low-field using hyperpolarized noble gases

    NASA Technical Reports Server (NTRS)

    Venkatesh, Arvind K.; Zhang, Adelaide X.; Mansour, Joey; Kubatina, Lyubov; Oh, Chang Hyun; Blasche, Gregory; Selim Unlu, M.; Balamore, Dilip; Jolesz, Ferenc A.; Goldberg, Bennett B.; Albert, Mitchell S.

    2003-01-01

    In hyperpolarized (HP) noble-gas magnetic resonance imaging, large nuclear spin polarizations, about 100,000 times that ordinarily obtainable at thermal equilibrium, are created in 3He and 129Xe. The enhanced signal that results can be employed in high-resolution MRI studies of void spaces such as in the lungs. In HP gas MRI the signal-to-noise ratio (SNR) depends only weakly on the static magnetic field (B(0)), making very low-field (VLF) MRI possible; indeed, it is possible to contemplate portable MRI using light-weight solenoids or permanent magnets. This article reports the first in vivo VLF MR images of the lungs in humans and in rats, obtained at a field of only 15 millitesla (150 Gauss).

  6. A comparison of multiparametric MRI modalities to discriminate prostate cancer tumours

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Carvajal, R. E.; Fargeas, A.; Gnep, K.; Rolland, Y.; Acosta, O.; de Crevoisier, R.

    2015-01-01

    Using multiparametric MRI (mpMRI) protocols to monitor prostate cancer could provide new insights into the biological mechanisms of developing tumours. Automatically discriminating tumour regions active area of research due to the complexity and plurality of cancer behaviour. This work evaluates four different Magnetic Resonance Imaging (MRI) image modalities, namely: Diffusion-Weighted Imaging evaluated at b = {0, 100, 1000}, Apparent Diffusion Coefficient and Dynamic Contrast Enhanced MRI, by extracting texture and functional features and then selecting the optimal ones to discriminate anatomical prostate regions in each modality. The images used were taken prior to radiotherapy from eight patients previously diagnosed with moderate risk of recurrent cancer. Finally, we compared the relevance of each modality to discriminate between healthy tissue and tumour cells.

  7. A comprehensive non-invasive framework for automated evaluation of acute renal transplant rejection using DCE-MRI.

    PubMed

    Khalifa, Fahmi; Abou El-Ghar, Mohamed; Abdollahi, Behnaz; Frieboes, Hermann B; El-Diasty, Tarek; El-Baz, Ayman

    2013-11-01

    The objective was to develop a novel and automated comprehensive framework for the non-invasive identification and classification of kidney non-rejection and acute rejection transplants using 2D dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The proposed approach consists of four steps. First, kidney objects are segmented from the surrounding structures with a geometric deformable model. Second, a non-rigid registration approach is employed to account for any local kidney deformation. In the third step, the cortex of the kidney is extracted in order to determine dynamic agent delivery, since it is the cortex that is primarily affected by the perfusion deficits that underlie the pathophysiology of acute rejection. Finally, we use an analytical function-based model to fit the dynamic contrast agent kinetic curves in order to determine possible rejection candidates. Five features that map the data from the original data space to the feature space are chosen with a k-nearest-neighbor (KNN) classifier to distinguish between acute rejection and non-rejection transplants. Our study includes 50 transplant patients divided into two groups: 27 patients with stable kidney function and the remainder with impaired kidney function. All of the patients underwent DCE-MRI, while the patients in the impaired group also underwent ultrasound-guided fine needle biopsy. We extracted the kidney objects and the renal cortex from DCE-MRI for accurate medical evaluation with an accuracy of 0.97 ± 0.02 and 0.90 ± 0.03, respectively, using the Dice similarity metric. In a cohort of 50 participants, our framework classified all cases correctly (100%) as rejection or non-rejection transplant candidates, which is comparable to the gold standard of biopsy but without the associated deleterious side-effects. Both the 95% confidence interval (CI) statistic and the receiver operating characteristic (ROC) analysis document the ability to separate rejection and non-rejection groups. The average plateau (AP) signal magnitude and the gamma-variate model functional parameter ? have the best individual discriminating characteristics. PMID:23775728

  8. Spatial and temporal reproducibility-based ranking of the independent components of BOLD fMRI data

    PubMed Central

    Zeng, Weiming; Qiu, Anqi; Chodkowski, BettyAnn; Pekar, James J.

    2009-01-01

    Independent component analysis (ICA) decomposes fMRI data into spatially independent maps and their corresponding time courses. However, distinguishing the neurobiologically and biophysically reasonable components from those representing noise and artifacts is not trivial. We present a simple method for the ranking of independent components, by assessing the resemblance between components estimated from all the data, and components estimated from only the odd– (or even–) numbered time points. We show that the meaningful independent components of fMRI data resemble independent components estimated from downsampled data, and thus tend to be highly ranked by the method. PMID:19286465

  9. Registration of Histology and MRI

    E-print Network

    Reuter, Martin

    Registration of Histology and MRI using Blockface as Intermediate Space Registering histological images with MR data is challenging due to: · 3D deformations between MR scanning and histological block, · 2D deformations during sectioning and mounting histology on slides (even tears, missing tissue

  10. C H A P T E R Distinguishing Imagination

    E-print Network

    Weisberg, Deena Skolnick

    C H A P T E R 75 Distinguishing Imagination from Reality6 Deena Skolnick Weisberg Children engage is the extent to which the child reproduces or continues the real world...the child has no imagination, and what

  11. Good Is Not Good Enough Deriving Optimal Distinguishers

    E-print Network

    Rioul, Olivier

    the leakage and the sensitive variable, both seen Annelie Heuser is a Google European fellow in the field of leakage models. Mangard et al. [11] argue that some distinguishers achieve success performance all explain the difference of success probabili

  12. Charles L. Brewer Award for Distinguished Teaching of Psychology

    ERIC Educational Resources Information Center

    American Psychologist, 2007

    2007-01-01

    This article announces the 2007 recipient of the Charles L. Brewer Award for Distinguished Teaching of Psychology: Baron Perlman. A brief biography, highlighting areas of special focus in Perlman's work, is provided.

  13. Distinguishable patterns of competition, collusion, and parallel action

    E-print Network

    Smith, James L.

    2003-01-01

    Alternative market structures are distinguishable by the degree of parallel action exhibited by producers. We show that the correlation between output levels varies systematically with the degree of interdependence among ...

  14. Distinguishing mangrove species with laboratory measurements of hyperspectral leaf reflectance

    E-print Network

    Wang, Le

    Distinguishing mangrove species with laboratory measurements of hyperspectral leaf reflectance LE step in developing classification procedures for remotely acquired hyperspectral mapping of mangrove canopies, we conducted a laboratory study of mangrove leaf spectral reflectance at a study site

  15. 28 CFR 301.318 - Civilian compensation laws distinguished.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Civilian compensation laws distinguished. 301.318 Section 301...INC., DEPARTMENT OF JUSTICE INMATE ACCIDENT COMPENSATION Compensation for Work-Related Physical Impairment or...

  16. 28 CFR 301.318 - Civilian compensation laws distinguished.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Civilian compensation laws distinguished. 301.318 Section 301...INC., DEPARTMENT OF JUSTICE INMATE ACCIDENT COMPENSATION Compensation for Work-Related Physical Impairment or...

  17. Measuring Channel Capacity to Distinguish Undue Influence James Newsome

    E-print Network

    Zakhor, Avideh

    by the Blaster and SQL Slammer worms. Influence measurement correctly distinguishes real attacks from taint- ing to control-flow hijacking and the execution of the attacker's injected code) [25]. Despite these attractive

  18. Classification algorithms with multi-modal data fusion could accurately distinguish neuromyelitis optica from multiple sclerosis.

    PubMed

    Eshaghi, Arman; Riyahi-Alam, Sadjad; Saeedi, Roghayyeh; Roostaei, Tina; Nazeri, Arash; Aghsaei, Aida; Doosti, Rozita; Ganjgahi, Habib; Bodini, Benedetta; Shakourirad, Ali; Pakravan, Manijeh; Ghana'ati, Hossein; Firouznia, Kavous; Zarei, Mojtaba; Azimi, Amir Reza; Sahraian, Mohammad Ali

    2015-01-01

    Neuromyelitis optica (NMO) exhibits substantial similarities to multiple sclerosis (MS) in clinical manifestations and imaging results and has long been considered a variant of MS. With the advent of a specific biomarker in NMO, known as anti-aquaporin 4, this assumption has changed; however, the differential diagnosis remains challenging and it is still not clear whether a combination of neuroimaging and clinical data could be used to aid clinical decision-making. Computer-aided diagnosis is a rapidly evolving process that holds great promise to facilitate objective differential diagnoses of disorders that show similar presentations. In this study, we aimed to use a powerful method for multi-modal data fusion, known as a multi-kernel learning and performed automatic diagnosis of subjects. We included 30 patients with NMO, 25 patients with MS and 35 healthy volunteers and performed multi-modal imaging with T1-weighted high resolution scans, diffusion tensor imaging (DTI) and resting-state functional MRI (fMRI). In addition, subjects underwent clinical examinations and cognitive assessments. We included 18 a priori predictors from neuroimaging, clinical and cognitive measures in the initial model. We used 10-fold cross-validation to learn the importance of each modality, train and finally test the model performance. The mean accuracy in differentiating between MS and NMO was 88%, where visible white matter lesion load, normal appearing white matter (DTI) and functional connectivity had the most important contributions to the final classification. In a multi-class classification problem we distinguished between all of 3 groups (MS, NMO and healthy controls) with an average accuracy of 84%. In this classification, visible white matter lesion load, functional connectivity, and cognitive scores were the 3 most important modalities. Our work provides preliminary evidence that computational tools can be used to help make an objective differential diagnosis of NMO and MS. PMID:25610795

  19. Real-time MRI-guided right heart catheterization in adults using passive catheters

    PubMed Central

    Ratnayaka, Kanishka; Faranesh, Anthony Z.; Hansen, Michael S.; Stine, Annette M.; Halabi, Majdi; Barbash, Israel M.; Schenke, William H.; Wright, Victor J.; Grant, Laurie P.; Kellman, Peter; Kocaturk, Ozgur; Lederman, Robert J.

    2013-01-01

    Aims Real-time MRI creates images with superb tissue contrast that may enable radiation-free catheterization. Simple procedures are the first step towards novel interventional procedures. We aim to perform comprehensive transfemoral diagnostic right heart catheterization in an unselected cohort of patients entirely using MRI guidance. Methods and results We performed X-ray and MRI-guided transfemoral right heart catheterization in consecutive patients undergoing clinical cardiac catheterization. We sampled both cavae and both pulmonary arteries. We compared success rate, time to perform key steps, and catheter visibility among X-ray and MRI procedures using air-filled or gadolinium-filled balloon-tipped catheters. Sixteen subjects (four with shunt, nine with coronary artery disease, three with other) underwent paired X-ray and MRI catheterization. Complete guidewire-free catheterization was possible in 15 of 16 under both. MRI using gadolinium-filled balloons was at least as successful as X-ray in all procedure steps, more successful than MRI using air-filled balloons, and better than both in entering the left pulmonary artery. Total catheterization time and individual procedure steps required approximately the same amount of time irrespective of image guidance modality. Catheter conspicuity was best under X-ray and next-best using gadolinium-filled MRI balloons. Conclusion In this early experience, comprehensive transfemoral right heart catheterization appears feasible using only MRI for imaging guidance. Gadolinium-filled balloon catheters were more conspicuous than air-filled ones. Further workflow and device enhancement are necessary for clinical adoption. PMID:22855740

  20. Top-Level System Designs for Hybrid Low-Field MRI-CT with Potential of Pulmonary Imaging

    NASA Astrophysics Data System (ADS)

    Yelleswarapu, Venkata R.; Liu, Fenglin; Cong, Wenxiang; Wang, Ge

    2014-11-01

    We previously discussed "omni-tomography", but intrinsic conflicts between the magnetic fields of the MRI and the X-ray tube within the CT are inherent. We propose that by using low-field MRI with a negligible fringe field at the site of the CT source, it is possible to create a CT-MRI system with minimal interference. Low field MRI is particularly useful for lung imaging, where hyperpolarized gas can enhance the signal. Three major designs were considered and simulated, with modifications in coil design and axis allowing for further variation. The first uses Halbach arrays to minimize magnetic fields outside, the second uses solenoids pairs with active shielding, and the third uses a rotating compact MRI-CT. Each system is low field, which may allow the implementation of a standard rotating CT. Both structural and functional information can be acquired simultaneously for a true hybrid image with matching temporal and spatial image acquisition.

  1. PET/MRI for Preoperative Planning in Patients with Soft Tissue Sarcoma: A Technical Report of Two Patients

    PubMed Central

    Loft, Annika; Jensen, Karl Erik; Daugaard, Søren; Petersen, Michael M.

    2013-01-01

    Clinical positron emission tomography (PET)/magnetic resonance imaging (MRI) acquisition protocols may improve the evaluation of soft tissue sarcomas (STS) prior to surgical planning. We examined two patients with lower extremity STS using a Siemens Biograph mMR PET/MRI scanner and the glucose analogue 18F-fluoro-deoxyglucose (FDG). We investigated clinically relevant tumor volumes and evaluated the relations to skeletal periosteum and nerve bundles. The patient scans suggest that FDG PET/MRI improved the edge detection, and invasion of tumor tissue into important adjacent anatomical structures can be evaluated. FDG PET/MRI also provided additional information compared to conventional Gadolinium enhanced MR imaging. The findings were proven by subsequent pathological examination of the resected tumor tissue. In the future, clinical FDG PET/MRI may be an important modality for preoperative planning, including radiation therapy planning in patients with STS. PMID:24368921

  2. PET/MRI for Preoperative Planning in Patients with Soft Tissue Sarcoma: A Technical Report of Two Patients.

    PubMed

    Loft, Annika; Jensen, Karl Erik; Löfgren, Johan; Daugaard, Søren; Petersen, Michael M

    2013-01-01

    Clinical positron emission tomography (PET)/magnetic resonance imaging (MRI) acquisition protocols may improve the evaluation of soft tissue sarcomas (STS) prior to surgical planning. We examined two patients with lower extremity STS using a Siemens Biograph mMR PET/MRI scanner and the glucose analogue 18F-fluoro-deoxyglucose (FDG). We investigated clinically relevant tumor volumes and evaluated the relations to skeletal periosteum and nerve bundles. The patient scans suggest that FDG PET/MRI improved the edge detection, and invasion of tumor tissue into important adjacent anatomical structures can be evaluated. FDG PET/MRI also provided additional information compared to conventional Gadolinium enhanced MR imaging. The findings were proven by subsequent pathological examination of the resected tumor tissue. In the future, clinical FDG PET/MRI may be an important modality for preoperative planning, including radiation therapy planning in patients with STS. PMID:24368921

  3. NI-72CORRELATION OF VOLUMETRICAL ANALYSES DERIVED FROM 18FET-PET AND MRI WITH OUTCOME IN GLIOBLASTOMA PATIENTS

    PubMed Central

    Suchorska, Bogdana; Jansen, Nathalie L.; Sosnova, Marketa; Janssen, Hendrik; Grabowski, Mark; Kreth, Friedrich-Wilhelm; Vogelbaum, Michael A.; Tonn, Joerg-Christian

    2014-01-01

    AIM: Both MRI and PET have been increasingly used for monitoring treatment response and adjustment of therapeutic strategies in glioma. The purpose of the currentstudy was to elucidate a possible prognostic influence of the initial tumor volume derived both from 18FET-PET as well as MRI on outcome in de-novo glioblastoma (GBM) patients. PATIENTS AND METHODS: 71 patients with newly diagnosed GBM who received 18FET-PET and MRI prior to microsurgery/biopsy and subsequent radio/chemotherapy according to the EORTC/NCIC protocolwere analysed. After co-registration, volumetrical analysis was performed on MRI and 18FET-PET data. Biological tumor volume (BTV) was defined on 18FET-PET using brain-to tumor ratio of 1.6. For MRI,T2/FLAIR as well as Gd-enhanced T1-weighted sequences with and without necrotic parts were correspondingly obtained in each patient. Correlation of initial tumor volume on each image modality with overall survival and progression free survival was performed. Log rank test was used for statistical analysis. RESULTS: Volumetrical analyses revealed the following distribution pattern: FLAIR volume > BTV1.6 >Gd-enhanced T1 volume with necrosis >Gd-enhanced T1 volume without necrosis. Patients with smaller BTV1.6 experienced longer OS and PFS (p= 0.01/0.03), while Gd-enhanced T1-weighted MRI without necrosis was the only MRI parameter associated with an improved OS and PFS (p = 0.03/p = 0.05). CONCLUSION: Biological tumor volume as determined by 18FET-PET and Gd-enhanced T1 volume without necrosis are associated with outcome in GBM. BTV seems to surmount volumetry obtained by conventional MRI techniques in depicting vital tumor tissue. This research was in part supported by Deutsche Krebshilfe/GGN/ 70-3163-Wi 3

  4. Ovarian Sertoli–Leydig cell tumors: MRI findings and pathological correlation

    PubMed Central

    2013-01-01

    Background To investigate the magnetic resonance imaging (MRI) characteristics of ovarian Sertoli-Leydig cell tumors (SLCT). Methods The clinical, MRI and pathological findings of five cases of SLCT were reviewed retrospectively. MRI appearances of tumors including laterality, shape and size, architecture, wall, septa and vegetation, signal intensity and contrast-enhancement pattern were evaluated and correlated with pathological findings. Results Two tumors were solid which appeared as low signal intensity on T1-weighted imaging (T1WI) and moderate on T2-weighted imaging (T2WI) with multiple small cysts in one of them. The remaining three SLCT were multilocular cystic with the irregularly thickened wall and septa, and with solid area and mural nodules in one of them. The cystic components had the same signal intensity as urine. All the solid components were intensely enhanced after administration of contrast medium. All five tumors were pathologically intermediate differentiation and at FIGO stage I. Conclusions SLCT demonstrate variable MRI morphological appearances. However, the irregularly thickened wall and septa, the moderate T2WI signal intensity and obvious enhancement in the solid components are three MRI features. PMID:24160866

  5. Multiwavelet-based feature extraction for MRI segmentation

    NASA Astrophysics Data System (ADS)

    Nezafat, Reza; Soltanian-Zadeh, Hamid

    1998-10-01

    In this paper, a new feature extraction technique, which is based on multiwavelet frame, is introduced and its application to MRI feature extraction is investigated. Energy calculation is used as the nonlinearity of the feature extraction procedure. An optimal linear transformation is applied to the resulting features to map them onto a 3D subspace in which normal tissues are orthonormal. For brain images, this subspace corresponds to three images which illustrate projections (similarities) of abnormal tissues to each of the normal tissues of the human brain (white matter, gray matter, CSF). The three images, referred to as eigenimages, are useful in diagnosis and treatment of patients with brain abnormalities. We show that the proposed feature extraction method extracts certain brain tumor texture features, which are otherwise invisible. The method is therefore expected to enhance image analysis of MRI studies of brain tumor patients.

  6. Perspectives on Porous Media MR in Clinical MRI

    NASA Astrophysics Data System (ADS)

    Sigmund, E. E.

    2011-03-01

    Many goals and challenges of research in natural or synthetic porous media are mirrored in quantitative medical MRI. This review will describe examples where MR techniques used in porous media (particularly diffusion-weighted imaging (DWI)) are applied to physiological pathologies. Tissue microstructure is one area with great overlap with porous media science. Diffusion-weighting (esp. in neurological tissue) has motivated models with explicit physical dimensions, statistical parameters, empirical descriptors, or hybrids thereof. Another clinically relevant microscopic process is active flow. Renal (kidney) tissue possesses significant active vascular / tubular transport that manifests as "pseudodiffusion." Cancerous lesions involve anomalies in both structure and flow. The tools of magnetic resonance and their interpretation in porous media has had great impact on clinical MRI, and continued cross-fertilization of ideas can only enhance the progress of both fields.

  7. MRI gadolinium-based contrast agents. Radiologists beware!

    PubMed

    Goullé, J-P; Cattanéo, A; Saussereau, E; Mahieu, L; Guerbet, M; Lacroix, C

    2009-09-01

    Gadolinium (Gd) is used in contrast agents as it enhances magnetic resonance imaging (MRI) signals. To reduce Gd toxicity, it is chelated into linear or macrocyclic complexes. Eight Gd-containing contrast agents have been approved by the European Medicines Agency (EMEA) for use in MRI, and six by the US Food and Drug Administration. Stability depends upon its physicochemical properties. When renal function is normal, the Gd is quickly cleared from the body by the kidneys. For patients with chronic kidney disease, the elimination is greatly reduced and Gd may be released from its chelate and deposit in body tissues, leading to nephrogenic systemic fibrosis (NSF). More than 200 cases of NSF have been reported in the world. NSF is characterized by an extensive fibrosis of skin and tissues, a very severe affection with possible lethal outcome. We propose recommendations to avoid the risk of NSF. PMID:19695369

  8. Automatic Denoising of Functional MRI Data: Combining Independent Component Analysis and Hierarchical Fusion of Classifiers

    PubMed Central

    Salimi-Khorshidi, Gholamreza; Douaud, Gwenaëlle; Beckmann, Christian F; Glasser, Matthew F; Griffanti, Ludovica; Smith, Stephen M

    2014-01-01

    Many sources of fluctuation contribute to the fMRI signal, and this makes identifying the effects that are truly related to the underlying neuronal activity difficult. Independent component analysis (ICA) - one of the most widely used techniques for the exploratory analysis of fMRI data - has shown to be a powerful technique in identifying various sources of neuronally-related and artefactual fluctuation in fMRI data (both with the application of external stimuli and with the subject “at rest”). ICA decomposes fMRI data into patterns of activity (a set of spatial maps and their corresponding time series) that are statistically independent and add linearly to explain voxel-wise time series. Given the set of ICA components, if the components representing “signal” (brain activity) can be distinguished form the “noise” components (effects of motion, non-neuronal physiology, scanner artefacts and other nuisance sources), the latter can then be removed from the data, providing an effective cleanup of structured noise. Manual classification of components is labour intensive and requires expertise; hence, a fully automatic noise detection algorithm that can reliably detect various types of noise sources (in both task and resting fMRI) is desirable. In this paper, we introduce FIX (“FMRIB’s ICA-based X-noiseifier”), which provides an automatic solution for denoising fMRI data via accurate classification of ICA components. For each ICA component FIX generates a large number of distinct spatial and temporal features, each describing a different aspect of the data (e.g., what proportion of temporal fluctuations are at high frequencies). The set of features is then fed into a multi-level classifier (built around several different Classifiers). Once trained through the hand-classification of a sufficient number of training datasets, the classifier can then automatically classify new datasets. The noise components can then be subtracted from (or regressed out of) the original data, to provide automated cleanup. On conventional resting-state fMRI (rfMRI) single-run datasets, FIX achieved about 95% overall accuracy. On high-quality rfMRI data from the Human Connectome Project, FIX achieves over 99% classification accuracy, and as a result is being used in the default rfMRI processing pipeline for generating HCP connectomes. FIX is publicly available as a plugin for FSL. PMID:24389422

  9. Dependence of DCE-MRI biomarker values on analysis algorithm

    PubMed Central

    Ng, Chaan S.; Wei, Wei; Bankson, James A.; Ravoori, Murali K.; Han, Lin; Brammer, David W.; Klumpp, Sherry; Waterton, John C.; Jackson, Edward F.

    2015-01-01

    Background Dynamic contrast-enhanced MRI (DCE-MRI) biomarkers have proven utility in tumors in evaluating microvascular perfusion and permeability, but it is unclear whether measurements made in different centers are comparable due to methodological differences. Purpose To evaluate how commonly utilized analytical methods for DCE-MRI biomarkers affect both the absolute parameter values and repeatability. Materials and Methods DCE-MRI was performed on three consecutive days in twelve rats bearing C6 xenografts. Endothelial transfer constant (Ktrans), extracellular extravascular space volume fraction (ve), and contrast agent reflux rate constant (kep) measures were computed using: 2-parameter (“Tofts” or “standard Kety”) vs. 3-parameter (“General Kinetic” or “extended Kety”) compartmental models (including blood plasma volume fraction (vp) with 3-parameter models); individual- vs. population-based vascular input functions (VIFs); and pixel-by-pixel vs. whole tumor-ROI. Variability was evaluated by within-subject coefficient of variation (wCV) and variance components analyses. Results DCE-MRI absolute parameter values and wCVs varied widely by analytical method. Absolute parameter values ranged, as follows, median Ktrans, 0.09–0.18 min-1; kep, 0.51–0.92 min-1; ve, 0.17–0.23; and vp, 0.02–0.04. wCVs also varied widely by analytical method, as follows: mean Ktrans, 32.9–61.9%; kep, 11.6–41.9%; ve, 16.1–54.9%; and vp, 53.9–77.2%. Ktrans and kep values were lower with 3- than 2-parameter modeling (p<0.0001); kep and vp were lower with pixel- than whole-ROI analyses (p<0.0006). wCVs were significantly smaller for ve, and larger for kep, with individual- than population-based VIFs. Conclusions DCE-MRI parameter values and repeatability can vary widely by analytical methodology. Absolute values of DCE-MRI biomarkers are unlikely to be comparable between different studies unless analyses are carefully standardized. PMID:26208254

  10. Dissociating dynamic probability and predictability in observed actions—an fMRI study

    PubMed Central

    Ahlheim, Christiane; Stadler, Waltraud; Schubotz, Ricarda I.

    2014-01-01

    The present fMRI study investigated whether human observers spontaneously exploit the statistical structure underlying continuous action sequences. In particular, we tested whether two different statistical properties can be distinguished with regard to their neural correlates: an action step's predictability and its probability. To assess these properties we used measures from information theory. Predictability of action steps was operationalized by its inverse, conditional entropy, which combines the number of possible action steps with their respective probabilities. Probability of action steps was assessed using conditional surprisal, which increases with decreasing probability. Participants were trained in an action observation paradigm with video clips showing sequences of 9–33 s length with varying numbers of action steps that were statistically structured according to a Markov chain. Behavioral tests revealed that participants implicitly learned this statistical structure, showing that humans are sensitive toward these probabilistic regularities. Surprisal (lower probability) enhanced the BOLD signal in the anterior intraparietal sulcus. In contrast, high conditional entropy, i.e., low predictability, was correlated with higher activity in dorsomedial prefrontal cortex, orbitofrontal gyrus, and posterior intraparietal sulcus. Furthermore, we found a correlation between the anterior hippocampus' response to conditional entropy with the extent of learning, such that the more participants had learnt the structure, the greater the magnitude of hippocampus activation in response to conditional entropy. Findings show that two aspects of predictions can be dissociated: an action's predictability is reflected in a top-down modulation of attentional focus, evident in increased fronto-parietal activation. In contrast, an action's probability depends on the identity of the stimulus itself, resulting in bottom-up driven processing costs in the parietal cortex. PMID:24847235

  11. Princeton MagnetoRotational Instability (MRI) Experiment: Overview and Recent Progress in the Search for the MRI

    NASA Astrophysics Data System (ADS)

    Schartman, E.; Ji, H.; Burin, M. J.; Cutler, R.; Heitzenroeder, P.; Liu, W.; Raftopoulos, S.; Waksman, J.; Goodman, J.; Stone, J.; Kageyama, A.

    2006-06-01

    The MagnetoRotational Instability (MRI) is likely to be the dominant mechanism for angular momentum transport in electrically conducting accretion disks, such as those found in Quasars, X-ray binaries, cataclysmic variables and possibly protoplanetary disks. To date, the MRI has not been convincingly demonstrated in the laboratory. The Princeton MagnetoRotational Instability Experiment investigates the MRI in a magnetized liquid Gallium flow between concentric spinning cylinders. The low aspect ratio of our apparatus is vulnerable to large boundary effects, which are mitigated by splitting the ends of the chamber into pairs of differentially rotating rings. Initial experiments in water demonstrate reduction of the boundary effects and a scaling of the velocity profile with Reynolds Number. Also investigated are non-linear hydrodynamic effects which have also been proposed to drive angular momentum transport in accretion disks. The role of purely hydrodynamic processes is uncertain, with experiments and simulations giving apparently different results. The apparatus will next be filled with Gallium to search for signatures of the MRI: namely, an amplification of the non-axial components of the magnetic field, and an enhanced effective viscosity coupling the inner and outer cylinders. Initial diagnostics measure torque and external radial magnetic fields. In the near future internal magnetic field and flow diagnostics will be implemented. Our main objectives are (1) to clearly demonstrate MRI; (2) to study its nonlinear behavior and angular momentum transport; (3) to compare with state-of-the-art simulations similar to those used for astrophysical disks. This work is supported by the US DOE, NSF, and NASA.

  12. Evaluation of Neovessels in Atherosclerotic Plaques of Rabbits Using an Albumin-Binding Intravascular Contrast Agent and MRI

    PubMed Central

    Cornily, Jean-Christophe; Hyafil, Fabien; Calcagno, Claudia; Briley-Saebo, Karen C.; Tunstead, James; Aguinaldo, Juan-Gilberto S.; Mani, Venkatesh; Lorusso, Vito; Cavagna, Friedrich M.; Fayad, Zahi A.

    2015-01-01

    Purpose To test whether B-22956/1, a novel intravascular contrast agent with a high affinity to serum albumin (Bracco Imaging SpA.), allowed quantifying neovessel and macrophage density in atherosclerotic plaques of rabbits using MRI. Materials and Methods A T1-weighted MRI of the aorta was acquired in 10 rabbits (7 atherosclerotic and 3 control rabbits) before and up to 2 h after intravenous injection of 100 µmol/kg of Gd-DTPA or 75 µmol/kg of B-22956/1. Plaque enhancement was measured at different time points. Immunohistochemistry was performed using anti-CD 31 antibodies and anti-RAM 11 antibodies to correlate to neovessel and macrophage density, respectively. Results MRI showed a significant plaque enhancement 2 h after B-22956/1 versus Gd-DTPA in the atherosclerotic group (39.75% versus 9.5%; P < 0.0001. Early atherosclerotic plaques (n = 146) enhancement positively correlates with neovessel density on corresponding histological sections (r = 0.42; P < 0.01). Enhancement of atherosclerotic plaques 2 h after injection of B-22956/1 correlated with macrophage density (r = 0.71; P < 0.01). Conclusion Enhancement of atherosclerotic plaques with MRI correlated with neovessel density at early time points after the injection of B-22956/1 and with macrophage density, at later time points. Hence, B-22956/1-enhanced MRI represents a promising imaging technique for the identification of “high-risk” plaques. PMID:18504763

  13. MRI in the assessment of a newborn with cervical teratoma.

    PubMed

    Green, J S; Dickinson, F L; Rickett, A; Moir, A

    1998-09-01

    Teratoma of the head and neck is a rare lesion comprising 6 % of all teratomas, with only 3 % occurring in the cervical region [1]. Most are non-malignant lesions consisting of a variety of tissues of variable maturity, commonly with neuroepithelial and thyroid elements. They often present as a large cystic mass in the neck of a neonate or infant and frequently cause respiratory embarrassment due to local mass effect necessitating urgent surgical intervention. They may be difficult to distinguish from cystic hygromas, both clinically and radiologically. Imaging plays an important role in the assessment of these lesions, especially in preparation for surgery. We present a case of cervical teratoma and emphasise the role of MRI. PMID:9732501

  14. Spatio-temporal registration of cardiac perfusion MRI exams using high-dimensional mutual information.

    PubMed

    Hamrouni, Sameh; Rougon, Nicolas; Preteux, Francoise

    2010-01-01

    Compensating for cardio-thoracic motion artifacts in contrast-enhanced cardiac perfusion MRI (p-MRI) sequences is a key issue for the quantitative assessment of myocardial iscæmia. The classical paradigm consists of registering each sequence frame on some reference using an intensity-based matching criterion. In this paper, we present a novel unsupervised method for the groupwise registration of cardiac p-MRI exams based on mutual information between high-dimensional feature distributions. Specifically, local contrast enhancement curves are used as a dense set of spatio-temporal features, and statistically matched to a target feature distribution derived from a registered reference template. Using consistent kth nearest neighbors entropy estimators further enables the variational optimization of the model over finite- and infinite-dimensional transform spaces. Experiments on simulated and natural datasets demonstrate its accuracy and relevance for the reliable assessment of regional perfusion. PMID:21096947

  15. A case of rheumatoid meningitis presented with generalized seizure in whom MRI images were helpful for the diagnosis.

    PubMed

    Yamashita, Kazuya; Terasaki, Yasukazu; Sakaguchi, Manabu; Nakatsuji, Yuji; Yoshizaki, Kazuyuki; Mochizuki, Hideki

    2015-12-23

    We report a 65-years-old woman with rheumatoid meningitis presented with a generalized seizure. She has a 18-year history of rheumatoid arthritis, which has been successfully treated. She developed a generalized seizure. She was diagnosed as having subarachnoid hemorrhage, because the brain magnetic resonance imaging (MRI) showed increased fluid attenuated inversion recovery (FLAIR) signals in her left frontoparietal subarachnoid space. After one month of clinical stabilization, she developed numbness and weakness in her right lower extremity that spread to her right upper extremity and face. Brain MRI showed progression of subarachnoid lesion on FLAIR image and leptomeningeal enhancement on gadolinium-enhanced T1 weighted image. She was diagnosed as having rheumatoid meningitis, and methylprednisolone pulse therapy was started. Then, her symptoms and MRI findings were rapidly improved. Though rheumatoid meningitis is rare and presents a difficulty in the diagnosis, MRI features may support the diagnosis. PMID:26511030

  16. Self-regulation of human brain activity using simultaneous real-time fMRI and EEG neurofeedback

    E-print Network

    Zotev, Vadim; Yuan, Han; Misaki, Masaya; Bodurka, Jerzy

    2014-01-01

    Neurofeedback is a promising approach for non-invasive modulation of human brain activity with applications for treatment of mental disorders and enhancement of brain performance. Neurofeedback techniques are commonly based on either electroencephalography (EEG) or real-time functional magnetic resonance imaging (rtfMRI). Advances in simultaneous EEG-fMRI have made it possible to combine the two approaches. Here we report the first implementation of simultaneous multimodal rtfMRI and EEG neurofeedback (rtfMRI-EEG-nf). It is based on a novel system for real-time integration of simultaneous rtfMRI and EEG data streams. We applied the rtfMRI-EEG-nf to training of emotional self-regulation in healthy subjects performing a positive emotion induction task based on retrieval of happy autobiographical memories. The participants were able to simultaneously regulate their BOLD fMRI activation of the left amygdala and frontal EEG power asymmetry in the high-beta band using the rtfMRI-EEG-nf. Our proof-of-concept results...

  17. Assessing therapy response of secreting pineal germ cell tumor on simultaneous 18F-choline PET/MRI.

    PubMed

    Panagiotidis, Emmanouil; Shankar, Ananth; Afaq, Asim; Bomanji, Jamshed

    2014-09-01

    An 18-year-old man presented with 6 weeks' history of diplopia, early morning headaches, and blurred vision; on ophthalmologic examination, Parinaud syndrome was revealed. Brain MRI scan showed a calcified pineal mass. Brain simultaneous PET/MRI with 18F-choline showed an avid enhancing mass occupying the pineal region with restricted diffusion. A second examination after chemotherapy demonstrated reduction in both size and radiotracer activity of the mass. Our study emphasizes the potential of simultaneous 18F-choline PET/MRI being a useful tool for contribution in the diagnosis and treatment assessment in a convenient way with minimal radiation exposure and reduced throughput patient time. PMID:24217533

  18. Potential utility of conventional MRI signs in diagnosing pseudoprogression in glioblastoma

    PubMed Central

    Gupta, A.; Shah, A.D.; Graber, J.J.; Zhang, Z.; Shi, W.; Holodny, A.I.; Omuro, A.M.P.

    2011-01-01

    Objective: To examine the potential utility of conventional MRI signs in differentiating pseudoprogression (PsP) from early progression (EP). Methods: This retrospective study reviewed initial postradiotherapy MRI scans of 321 patients with glioblastoma undergoing chemotherapy and radiotherapy. A total of 93 patients were found to have new or increased enhancing mass lesions, raising the possibility of PsP. Final diagnosis of PsP or EP was established upon review of surgical specimens from a second resection or by clinical and radiologic follow-up. A total of 11 MRI signs potentially helpful in the differentiation between PsP and EP were examined on the initial post-RT MRI and were correlated with the final diagnosis through ?2 or Fisher exact test. Results: Sixty-three (67.7%) of the 93 patients had EP, of which 22 (34.9%) were diagnosed by pathology. Thirty patients (32.3%) had PsP; 6 (16.7% of the 30) were diagnosed by pathology. Subependymal enhancement was predictive for EP (p = 0.001) with 38.1% sensitivity, 93.3% specificity, and 41.8% negative predictive value. The other 10 signs had no predictive value (p = 0.06–1.0). Conclusions: Conventional MRI signs have limited utility in diagnosing PsP in patients with recently treated glioblastomas and worsening enhancing lesions. We did not find a sign with a high negative predictive value for PsP that would have been the most useful for the clinical physician. When present, subependymal spread of the enhancing lesion is a useful MRI marker in identifying EP rather than PsP. Neurology® 2011;76:1918–1924 PMID:21624991

  19. How spatial abilities enhance, and are enhanced by, dental education Mary Hegarty a,

    E-print Network

    Montello, Daniel R.

    central to understanding medical images, including those produced by CT, MRI, X-ray, and ultrasoundHow spatial abilities enhance, and are enhanced by, dental education Mary Hegarty a, , Madeleine form 28 January 2008 Accepted 5 April 2008 Keywords: Spatial abilities Dental education Mental

  20. MRI in insulinomas: preliminary findings.

    PubMed

    Liessi, G; Pasquali, C; D'Andrea, A A; Scandellari, C; Pedrazzoli, S

    1992-01-01

    After establishing the diagnosis of an insulinoma, most surgeons prefer preoperative localization. Selective arteriography is usually considered the gold standard for this purpose. Recently, computed tomography (CT) and preoperative US have contended the role to angiography. MRI has been used in few cases of endocrine pancreatic tumors, and its role in this particular field has to be defined. Between November 1988 and September 1990 we evaluated 7 adult patients who had had surgery in our Surgical Department. Eight tumors were resected in 6 patients who were cured; in an 18-year-old woman surgical treatment was unsuccessful. Arteriography, CT, preoperative US, MRI and intraoperative US detected 2, 6, 6, 5 and 6 tumors, respectively. Two insulinomas (0.2 and 0.7 cm) were found at histologic examination in resected specimen. The ability of intraoperative US and careful surgical exploration to resolve more than 90% of cases makes the preoperative use of arteriography and CT of questionable value. If further experience confirms these findings, US and MRI may suffice. PMID:1563404

  1. MRI Phenotype in Renal Cancer

    PubMed Central

    Campbell, Naomi; Rosenkrantz, Andrew B.; Pedrosa, Ivan

    2015-01-01

    Renal cell carcinoma (RCC) is most commonly diagnosed as an incidental finding on cross-sectional imaging and represents a significant clinical challenge. Although most patients have a surgically curable lesion at the time of diagnosis, the variability in the biologic behavior of the different histologic subtypes and tumor grade of RCC, together with the increasing array of management options, creates uncertainty for the optimal clinical approach to individual patients. State-of-the-art magnetic resonance imaging (MRI) provides a comprehensive assessment of renal lesions that includes multiple forms of tissue contrast as well as functional parameters, which in turn provides information that helps to address this dilemma. In this article, we review this evolving and increasingly comprehensive role of MRI in the detection, characterization, perioperative evaluation, and assessment of the treatment response of renal neoplasms. We emphasize the ability of the imaging “phenotype” of renal masses on MRI to help predict the histologic subtype, grade, and clinical behavior of RCC. PMID:24690616

  2. Optimizing real time fMRI neurofeedback for therapeutic discovery and development

    PubMed Central

    Stoeckel, L.E.; Garrison, K.A.; Ghosh, S.; Wighton, P.; Hanlon, C.A.; Gilman, J.M.; Greer, S.; Turk-Browne, N.B.; deBettencourt, M.T.; Scheinost, D.; Craddock, C.; Thompson, T.; Calderon, V.; Bauer, C.C.; George, M.; Breiter, H.C.; Whitfield-Gabrieli, S.; Gabrieli, J.D.; LaConte, S.M.; Hirshberg, L.; Brewer, J.A.; Hampson, M.; Van Der Kouwe, A.; Mackey, S.; Evins, A.E.

    2014-01-01

    While reducing the burden of brain disorders remains a top priority of organizations like the World Health Organization and National Institutes of Health, the development of novel, safe and effective treatments for brain disorders has been slow. In this paper, we describe the state of the science for an emerging technology, real time functional magnetic resonance imaging (rtfMRI) neurofeedback, in clinical neurotherapeutics. We review the scientific potential of rtfMRI and outline research strategies to optimize the development and application of rtfMRI neurofeedback as a next generation therapeutic tool. We propose that rtfMRI can be used to address a broad range of clinical problems by improving our understanding of brain–behavior relationships in order to develop more specific and effective interventions for individuals with brain disorders. We focus on the use of rtfMRI neurofeedback as a clinical neurotherapeutic tool to drive plasticity in brain function, cognition, and behavior. Our overall goal is for rtfMRI to advance personalized assessment and intervention approaches to enhance resilience and reduce morbidity by correcting maladaptive patterns of brain function in those with brain disorders. PMID:25161891

  3. The use of MRI to assist the section selections for classical pathology assessment of neurotoxicity.

    PubMed

    Hanig, Joseph; Paule, Merle G; Ramu, Jaivijay; Schmued, Larry; Konak, Tetyana; Chigurupati, Srinivasulu; Slikker, William; Sarkar, Sumit; Liachenko, Serguei

    2014-12-01

    MRI was utilized to probe T2 changes in living brain following exposure of rats to one of ten classical neurotoxicants. Brains were subsequently perfused for classical neuropathology examination. This approach was predicated on the assumption that the T2 changes represent loci of neurotoxicity encompassing those seen using neuropathology techniques. The traditional neurotoxicologic approach of selecting a few arbitrary brain sections is dramatically improved by MRI targeting that can indicate the location(s) at which to collect "smart sections" for subsequent workup. MRI scans can provide the equivalent of 64 coronal sections; the number estimated for full coverage of the rat brain if only traditional neuropathology is utilized. Use of MRI allows each animal to serve as its own control as well as longitudinal observations of the life cycle of the neurotoxic lesion(s) (inception, apex and regression). Optimization of time of sacrifice and selection of an appropriate stain based on MRI-identified brain areas could be greatly enhanced should this approach prove successful. The application of full brain MRI imaging that informs neuropathology offers the potential to dramatically improve detection of neurotoxicity produced by new drugs and facilitate new drug development, review and approval processes, and to qualify an imaging biomarker of neuropathology. PMID:25265367

  4. Vessel calibre—a potential MRI biomarker of tumour response in clinical trials

    PubMed Central

    Emblem, Kyrre E.; Farrar, Christian T.; Gerstner, Elizabeth R.; Batchelor, Tracy T.; Borra, Ronald J. H.; Rosen, Bruce R.; Sorensen, A. Gregory; Jain, Rakesh K.

    2015-01-01

    Our understanding of the importance of blood vessels and angiogenesis in cancer has increased considerably over the past decades, and the assessment of tumour vessel calibre and structure has become increasingly important for in vivo monitoring of therapeutic response. The preferred method for in vivo imaging of most solid cancers is MRI, and the concept of vessel-calibre MRI has evolved since its initial inception in the early 1990s. Almost a quarter of a century later, unlike traditional contrast-enhanced MRI techniques, vessel-calibre MRI remains widely inaccessible to the general clinical community. The narrow availability of the technique is, in part, attributable to limited awareness and a lack of imaging standardization. Thus, the role of vessel-calibre MRI in early phase clinical trials remains to be determined. By contrast, regulatory approvals of antiangiogenic agents that are not directly cytotoxic have created an urgent need for clinical trials incorporating advanced imaging analyses, going beyond traditional assessments of tumour volume. To this end, we review the field of vessel-calibre MRI and summarize the emerging evidence supporting the use of this technique to monitor response to anticancer therapy. We also discuss the potential use of this biomarker assessment in clinical imaging trials and highlight relevant avenues for future research. PMID:25113840

  5. Dynamic MRI using iron oxide nanoparticles to assess early vascular effects of antiangiogenic versus corticosteroid treatment in a glioma model.

    PubMed

    Varallyay, Csanad G; Muldoon, Leslie L; Gahramanov, Seymur; Wu, Yingjen J; Goodman, James A; Li, Xin; Pike, Martin M; Neuwelt, Edward A

    2009-04-01

    The vascular effects of antiangiogenic treatment may pose problems for evaluating brain tumor response based on contrast-enhanced magnetic resonance imaging (MRI). We used serial dynamic contrast-enhanced MRI at 12 T to assess vascular responses to antiangiogenic versus steroid therapy. Athymic rats with intracerebral U87MG human glioma (n=17) underwent susceptibility-weighted perfusion MRI with ferumoxytol, a solely intravascular ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle, followed by T1-weighted dynamic gadodiamide-enhanced MRI to measure vascular permeability. Rats were imaged before and after 24, 48, and 72 h of treatment with the antiangiogenic agent bevacizumab or the corticosteroid dexamethasone. Contrast agent extravasation was seen rapidly after gadodiamide, but not with ferumoxytol administration. Bevacizumab significantly decreased the blood volume and decreased permeability in tumors as determined by increased time-to-peak enhancement. A single dose of 45 mg/kg bevacizumab resulted in changes analogous to dexamethasone given in an extremely high dose (12 mg/kg per day), and was significantly more effective than dexamethasone at 2 mg/kg per day. We conclude that dynamic perfusion MRI measurements with ferumoxytol USPIO to assess cerebral blood volume, along with dynamic gadodiamide-enhanced MR to assess vascular permeability, hold promise in more accurately detecting therapeutic responses to antiangiogenic therapy. PMID:19142191

  6. Multi-Photon Interference and Temporal Distinguishability of Photons

    E-print Network

    Z. Y. Ou

    2007-08-24

    A number of recent interference experiments involving multiple photons are reviewed. These experiments include generalized photon bunching effects, generalized Hong-Ou-Mandel interference effects and multi-photon interferometry for demonstrations of multi-photon de Broglie wavelength. The multi-photon states used in these experiments are from two pairs of photons in parametric down-conversion. We find that the size of the interference effect in these experiments, characterized by the visibility of interference pattern, is governed by the degree of distinguishability among different pairs of photons. Based on this discovery, we generalize the concept of multi-photon temporal distinguishability and relate it to a number of multi-photon interference effects. Finally, we make an attempt to interpret the coherence theory by the multi-photon interference via the concept of temporal distinguishability of photons.

  7. Local distinguishability of maximally entangled states in canonical form

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Chao; Gao, Fei; Qin, Su-Juan; Zuo, Hui-Juan; Wen, Qiao-Yan

    2015-10-01

    In this paper, we mainly study the local distinguishability of mutually orthogonal maximally entangled states in canonical form. In d ? d, Nathanson (Phys Rev A 88:062316, 2013) presented a feasible necessary and sufficient condition for distinguishing the general bipartite quantum states by one-way local operations and classical communication (LOCC). However, for maximally entangled states in canonical form, it is still unknown how to more effectively judge whether there exists a state such that those unitary operators corresponding to those maximally entangled states are pairwise orthogonal. In this work, we exhibit one method which can be used to more effectively judge it. Furthermore, we construct some sets of maximally entangled states and can easily know that those states are not distinguished by one-way LOCC with the help of our new method.

  8. Saline as the Sole Contrast Agent for Successful MRI-guided Epidural Injections

    SciTech Connect

    Deli, Martin; Mateiescu, Serban Busch, Martin; Becker, Jan Garmer, Marietta Groenemeyer, Dietrich

    2013-06-15

    Purpose. To assess the performance of sterile saline solution as the sole contrast agent for percutaneous magnetic resonance imaging (MRI)-guided epidural injections at 1.5 T. Methods. A retrospective analysis of two different techniques of MRI-guided epidural injections was performed with either gadolinium-enhanced saline solution or sterile saline solution for documentation of the epidural location of the needle tip. T1-weighted spoiled gradient echo (FLASH) images or T2-weighted single-shot turbo spin echo (HASTE) images visualized the test injectants. Methods were compared by technical success rate, image quality, table time, and rate of complications. Results. 105 MRI-guided epidural injections (12 of 105 with gadolinium-enhanced saline solution and 93 of 105 with sterile saline solution) were performed successfully and without complications. Visualization of sterile saline solution and gadolinium-enhanced saline solution was sufficient, good, or excellent in all 105 interventions. For either test injectant, quantitative image analysis demonstrated comparable high contrast-to-noise ratios of test injectants to adjacent body substances with reliable statistical significance levels (p < 0.001). The mean table time was 22 {+-} 9 min in the gadolinium-enhanced saline solution group and 22 {+-} 8 min in the saline solution group (p = 0.75). Conclusion. Sterile saline is suitable as the sole contrast agent for successful and safe percutaneous MRI-guided epidural drug delivery at 1.5 T.

  9. How to scan polymer gels with MRI?

    NASA Astrophysics Data System (ADS)

    De Deene, Y.

    2013-06-01

    The absorbed radiation dose fixated in a polymer gel dosimeter can be read out by several methods such as magnetic resonance imaging (MRI), optical CT, X-ray CT and ultrasound with MRI being the first method that was explored. Although MRI was considered as an elegant scanning technique, readily available in most hospitals, it was later found that using a non-optimized imaging protocol may result in unacceptable deviations in the obtained dose distribution. Although most medical physicists have an understanding of the basic principles of magnetic resonance imaging (MRI), the optimization of quantitative imaging sequences and protocols is often perceived as the work of MRI experts. In this paper, we aim at providing the reader with some easy guidelines in how to obtain reliable quantitative MRI maps.

  10. How to scan polymer gels with MRI?

    NASA Astrophysics Data System (ADS)

    De Deene, Yves

    2010-11-01

    The absorbed radiation dose fixated in a polymer gel dosimeter can be read out by several methods such as magnetic resonance imaging (MRI), optical CT, X-ray CT and ultrasound with MRI being the first method that was explored. Although MRI was considered as an elegant scanning technique, readily available in most hospitals, it was later found that using a non-optimized imaging protocol may result in unacceptable deviations in the obtained dose distribution. Although most medical physicists have an understanding of the basic principles of magnetic resonance imaging (MRI), the optimization of quantitative imaging sequences and protocols is often perceived as the work of MRI experts. In this paper, we aim at providing the reader with some easy guidelines in how to obtain reliable quantitative MRI maps.

  11. The person in the purchase: narcissistic consumers prefer products that positively distinguish them.

    PubMed

    Lee, Seung Yun; Gregg, Aiden P; Park, Seong Hoon

    2013-08-01

    Narcissists, who seek keenly to self-enhance, strive to positively distinguish themselves. Might they therefore be inclined to purchase consumer products that enable them to do so? Study 1 found that narcissism, but not self-esteem, predicted dispositions to purchase products for the purpose of promoting personal uniqueness. Studies 2 and 3 found that narcissism predicted greater interest in exclusive, customizable, and personalizable products. Study 3 also found participants higher in narcissism regarded their prized possessions as less likely to be owned by others. Finally, Studies 3 and 4 found that interest in a hypothetical product, respectively, to be bought either for oneself or someone else, covaried with an experimental manipulation of product exclusivity and scarcity, but principally when levels of narcissism were high. Our findings illustrate the impact of narcissism on consumer preferences and support an agentic interpretation of narcissistic self-enhancement. PMID:23773040

  12. MRI Visualization of Staphyloccocus aureus-Induced Infective Endocarditis in Mice

    PubMed Central

    Ring, Janine; Hoerr, Verena; Tuchscherr, Lorena; Kuhlmann, Michael T.; Löffler, Bettina; Faber, Cornelius

    2014-01-01

    Infective endocarditis (IE) is a severe and often fatal disease, lacking a fast and reliable diagnostic procedure. The purpose of this study was to establish a mouse model of Staphylococcus aureus-induced IE and to develop a MRI technology to characterize and diagnose IE. To establish the mouse model of hematogenous IE, aortic valve damage was induced by placing a permanent catheter into right carotid artery. 24 h after surgery, mice were injected intravenously with either iron particle-labeled or unlabeled S. aureus (strain 6850). To distinguish the effect of IE from mere tissue injury or recruited macrophages, subgroups of mice received sham surgery prior to infection (n?=?17), received surgery without infection (n?=?8), or obtained additionally injection of free iron particles to label macrophages (n?=?17). Cardiac MRI was performed 48 h after surgery using a self-gated ultra-short echo time (UTE) sequence (TR/TE, 5/0.31 ms; in-plane/slice, 0.125/1 mm; duration, 12?08 min) to obtain high-resolution, artifact-free cinematographic images of the valves. After MRI, valves were either homogenized and plated on blood agar plates for determination of bacterial titers, or sectioned and stained for histology. In the animal model, both severity of the disease and mortality increased with bacterial numbers. Infection with 105 S. aureus bacteria reliably caused endocarditis with vegetations on the valves. Cinematographic UTE MRI visualised the aortic valve over the cardiac cycle and allowed for detection of bacterial vegetations, while mere tissue trauma or labeled macrophages were not detected. Iron labeling of S. aureus was not required for detection. MRI results were consistent with histology and microbial assessment. These data showed that S. aureus-induced IE in mice can be detected by MRI. The established mouse model allows for investigation of the pathophysiology of IE, testing of novel drugs and may serve for the development of a clinical diagnostic strategy. PMID:25229324

  13. MRI visualization of Staphyloccocus aureus-induced infective endocarditis in mice.

    PubMed

    Ring, Janine; Hoerr, Verena; Tuchscherr, Lorena; Kuhlmann, Michael T; Löffler, Bettina; Faber, Cornelius

    2014-01-01

    Infective endocarditis (IE) is a severe and often fatal disease, lacking a fast and reliable diagnostic procedure. The purpose of this study was to establish a mouse model of Staphylococcus aureus-induced IE and to develop a MRI technology to characterize and diagnose IE. To establish the mouse model of hematogenous IE, aortic valve damage was induced by placing a permanent catheter into right carotid artery. 24 h after surgery, mice were injected intravenously with either iron particle-labeled or unlabeled S. aureus (strain 6850). To distinguish the effect of IE from mere tissue injury or recruited macrophages, subgroups of mice received sham surgery prior to infection (n?=?17), received surgery without infection (n?=?8), or obtained additionally injection of free iron particles to label macrophages (n?=?17). Cardiac MRI was performed 48 h after surgery using a self-gated ultra-short echo time (UTE) sequence (TR/TE, 5/0.31 ms; in-plane/slice, 0.125/1 mm; duration, 12?08 min) to obtain high-resolution, artifact-free cinematographic images of the valves. After MRI, valves were either homogenized and plated on blood agar plates for determination of bacterial titers, or sectioned and stained for histology. In the animal model, both severity of the disease and mortality increased with bacterial numbers. Infection with 105 S. aureus bacteria reliably caused endocarditis with vegetations on the valves. Cinematographic UTE MRI visualised the aortic valve over the cardiac cycle and allowed for detection of bacterial vegetations, while mere tissue trauma or labeled macrophages were not detected. Iron labeling of S. aureus was not required for detection. MRI results were consistent with histology and microbial assessment. These data showed that S. aureus-induced IE in mice can be detected by MRI. The established mouse model allows for investigation of the pathophysiology of IE, testing of novel drugs and may serve for the development of a clinical diagnostic strategy. PMID:25229324

  14. Phlebosclerotic colitis that was difficult to distinguish from collagenous colitis.

    PubMed

    Hozumi, Hideaki; Hokari, Ryota; Shimizu, Motonori; Maruta, Koji; Narimatsu, Kazuyuki; Sato, Hirokazu; Sato, Shingo; Ueda, Toshihide; Higashiyama, Masaaki; Watanabe, Chikako; Komoto, Shunsuke; Tomita, Kengo; Kawaguchi, Atsushi; Nagao, Shigeaki; Miura, Soichiro

    2014-07-01

    Phlebosclerotic colitis is a rare and recently known disease entity and its etiology is still to be elucidated. Some phlebosclerotic colitis cases are difficult to distinguish from collagenous colitis because of the similarity of pathological findings. In all Japanese case reports of phlebosclerotic colitis in which an association with the use of Chinese herbal medicine is suspected, sansisi (gardenia fruit) was included, suggesting pathogenesis of this disease. We report a case of phlebosclerotic colitis that wasdifficult to be distinguished from collagenous colitis, and an association with the use of Chinese herbal medicine was suspected as the cause of the disease. PMID:23902595

  15. Distinguishing succulent plants from crop and woody plants

    NASA Technical Reports Server (NTRS)

    Gausman, H. W.; Escobar, D. E.; Everitt, J. H.; Richardson, A. J.; Rodriguez, R. R.

    1978-01-01

    We compared laboratory spectrophotometrically measured leaf reflectances of six succulents (peperomia, possum-grape, prickly pear, spiderwort, Texas tuberose, wolfberry) with those of four nonsucculents (cenizo, honey mesquite, cotton, sugarcane) for plant species discrimination. Succulents (average leaf water content of 92.2 percent) could be distinguished from nonsucculents (average leaf water content of 71.2 percent) within the near-infrared water absorption waveband (1.35 to 2.5 microns). This was substantiated by field spectrophotometric reflectances of plant canopies. Sensor bands encompassing either the 1.6- or 2.2-wavelengths may be useful to distinguish succulent from nonsucculent plant species.

  16. Award for Distinguished Contributions to the International Advancement of Psychology.

    PubMed

    2015-11-01

    The Award for Distinguished Contributions to the International Advancement of Psychology is given to individuals who have made sustained and enduring contributions to international cooperation and the advancement of knowledge in psychology. The 2015 recipient of the APA Award for Distinguished Contributions to the International Advancement of Psychology was selected by the 2014 Committee on International Relations in Psychology (CIRP). The winners for 1991 through 2015 are listed here. The 2015 award winner is Walter J. Lonner. (PsycINFO Database Record PMID:26618977

  17. [Marketing of MRI in the world].

    PubMed

    Lavayssière, R; Cabée, A E

    1990-01-01

    The authors are recalling the main tendancies of the medical imaging world market before studying MRI diffusion in the 3 great sectors, USA, Europe and Japan. MRI diffusion is highly regulated in Europe but in the 2 other areas the growth of MRI was slower than the CT growth for the same period of time for medical, technological and financial reasons. The market evolution with the uprising of the mid-field niche and industrial offers will be presented. PMID:2254867

  18. Comparison of Acoustic Radiation Force Impulse Imaging Derived Carotid Plaque Stiffness With Spatially Registered MRI Determined Composition.

    PubMed

    Doherty, Joshua R; Dahl, Jeremy J; Kranz, Peter G; El Husseini, Nada; Chang, Hing-Chiu; Chen, Nan-Kuei; Allen, Jason D; Ham, Katherine L; Trahey, Gregg E

    2015-11-01

    Measurements of plaque stiffness may provide important prognostic and diagnostic information to help clinicians distinguish vulnerable plaques containing soft lipid pools from more stable, stiffer plaques. In this preliminary study, we compare in vivo ultrasonic Acoustic Radiation Force Impulse (ARFI) imaging derived measures of carotid plaque stiffness with composition determined by spatially registered Magnetic Resonance Imaging (MRI) in five human subjects with stenosis > 50%. Ultrasound imaging was implemented on a commercial diagnostic scanner with custom pulse sequences to collect spatially registered 2D longitudinal B-mode and ARFI images. A standardized, multi-contrast weighted MRI sequence was used to obtain 3D Time of Flight (TOF), T1 weighted (T1W), T2 weighted (T2W), and Proton Density Weighted (PDW) transverse image stacks of volumetric data. The MRI data was segmented to identify lipid, calcium, and normal loose matrix components using commercially available software. 3D MRI segmented plaque models were rendered and spatially registered with 2D B-mode images to create fused ultrasound and MRI volumetric images for each subject. ARFI imaging displacements in regions of interest (ROIs) derived from MRI segmented contours of varying composition were compared. Regions of calcium and normal loose matrix components identified by MRI presented as homogeneously stiff regions of similarly low (typically ? 1 ?m) displacement in ARFI imaging. MRI identified lipid pools > 2 mm(2), found in three out of five subjects, presented as softer regions of increased displacement that were on average 1.8 times greater than the displacements in adjacent regions of loose matrix components in spatially registered ARFI images. This work provides early evidence supporting the use of ARFI imaging to noninvasively identify lipid regions in carotid artery plaques in vivo that are believed to increase the propensity of a plaque to rupture. Additionally, the results provide early training data for future studies and aid in the interpretation and possible clinical utility of ARFI imaging for identifying the elusive vulnerable plaque. PMID:25974933

  19. Imaging in rectal cancer with emphasis on local staging with MRI

    PubMed Central

    Arya, Supreeta; Das, Deepak; Engineer, Reena; Saklani, Avanish

    2015-01-01

    Imaging in rectal cancer has a vital role in staging disease, and in selecting and optimizing treatment planning. High-resolution MRI (HR-MRI) is the recommended method of first choice for local staging of rectal cancer for both primary staging and for restaging after preoperative chemoradiation (CT-RT). HR-MRI helps decide between upfront surgery and preoperative CT-RT. It provides high accuracy for prediction of circumferential resection margin at surgery, T category, and nodal status in that order. MRI also helps assess resectability after preoperative CT-RT and decide between sphincter saving or more radical surgery. Accurate technique is crucial for obtaining high-resolution images in the appropriate planes for correct staging. The phased array external coil has replaced the endorectal coil that is no longer recommended. Non-fat suppressed 2D T2-weighted (T2W) sequences in orthogonal planes to the tumor are sufficient for primary staging. Contrast-enhanced MRI is considered inappropriate for both primary staging and restaging. Diffusion-weighted sequence may be of value in restaging. Multidetector CT cannot replace MRI in local staging, but has an important role for evaluating distant metastases. Positron emission tomography-computed tomography (PET/CT) has a limited role in the initial staging of rectal cancer and is reserved for cases with resectable metastatic disease before contemplating surgery. This article briefly reviews the comprehensive role of imaging in rectal cancer, describes the role of MRI in local staging in detail, discusses the optimal MRI technique, and provides a synoptic report for both primary staging and restaging after CT-RT in routine practice. PMID:25969638

  20. MRI Inner Ear Imaging and Tone Burst Electrocochleography in the Diagnosis of Ménière’s Disease

    PubMed Central

    Hornibrook, Jeremy; Flook, Edward; Greig, Sam; Babbage, Melissa; Goh, Tony; Coates, Mark; Care, Rachel; Bird, Philip

    2015-01-01

    Objective To compare the sensitivity of gadolinium MRI inner imaging with tone burst electrocochleography (EcochG) for diagnosing endolymphatic hydrops. Study Design A prospective study on patients who were to have an MRI scan to exclude retrocochlear pathology. Setting Tertiary care center. Patients One hundred and two patients: 57 patients with Possible, Probable, or Definite Ménière’s Disease, 25 with asymmetrical hearing loss, 18 with sudden sensorineural hearing loss, and 2 with unilateral tinnitus had additional MRI inner ear imaging and click and tone burst stimulus EcochG testing. Intervention Diagnostic. Main Outcome Measure To compare the sensitivity of the two techniques. Results In 30 patients with symptom-based Definite Ménière’s Disease, tone burst EcochG was positive in 25 (83%) and the click EcochG was positive in 9/30 (30%), and gadolinium MRI imaging diagnosed hydrops in 14 (47%). A positive result for either MRI imaging or tone burst EcochG was seen in 26 patients (87%). In 14 subjects with symptom-based Probable Ménière’s Disease, 10 (71%) had either a positive EcochG or MRI. In 13 with Possible Ménière’s Disease, four (31%) had a positive EcochG or MRI. Conclusion This study confirms the greatly enhanced diagnostic sensitivity of tone burst EcochG over click response in diagnosing endolymphatic hydrops in Ménière’s disease. Even though adequate MRI imaging was achieved in 90%, tone burst EcochG was a more sensitive test. PMID:25985318

  1. Distinguishing between $?$CDM and modified gravity with future observations of cosmic growth rate

    E-print Network

    Koichi Hirano

    2015-12-30

    A probability of distinguishing between $\\Lambda$CDM model and modified gravity is studied by using the future observations for the growth rate of cosmic structure (Euclid redshift survey). Adopting extended DGP model, Kinetic Gravity Braiding model, and Galileon model as modified gravity, we compare predicted cosmic growth rate by models to the mock observational data. The growth rate $f\\sigma_8$ in the original DGP model is suppressed compared with the $\\Lambda$CDM case, for the same value of the current density parameter of matter $\\Omega_{m,0}$, because of the suppression of effective gravitational constant. In case of the kinetic gravity braiding model and the Galileon model, the growth rate $f\\sigma_8$ is enhanced compared with the $\\Lambda$CDM case, for the same value of $\\Omega_{m,0}$, because of the enhancement of effective gravitational constant. For future observational data of the cosmic growth rate (Euclid), compatible value of $\\Omega_{m,0}$ are different by models, furthermore $\\Omega_{m,0}$ can be stringently constrained. Thus, we find the $\\Lambda$CDM model is distinguishable from modified gravity by combining the growth rate data of the Euclid with other observations.

  2. 10 CFR 1002.3 - Custody of official seal and distinguishing flags.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Custody of official seal and distinguishing flags. 1002.3...ENERGY (GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG General § 1002.3 Custody of official seal and distinguishing flags. The...

  3. 10 CFR 1002.3 - Custody of official seal and distinguishing flags.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Custody of official seal and distinguishing flags. 1002.3...ENERGY (GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG General § 1002.3 Custody of official seal and distinguishing flags. The...

  4. 10 CFR 1002.3 - Custody of official seal and distinguishing flags.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Custody of official seal and distinguishing flags. 1002.3...ENERGY (GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG General § 1002.3 Custody of official seal and distinguishing flags. The...

  5. 10 CFR 1002.3 - Custody of official seal and distinguishing flags.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Custody of official seal and distinguishing flags. 1002.3...ENERGY (GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG General § 1002.3 Custody of official seal and distinguishing flags. The...

  6. 10 CFR 1002.3 - Custody of official seal and distinguishing flags.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Custody of official seal and distinguishing flags. 1002.3...ENERGY (GENERAL PROVISIONS) OFFICIAL SEAL AND DISTINGUISHING FLAG General § 1002.3 Custody of official seal and distinguishing flags. The...

  7. Breast imaging with ultrasound tomography: a comparative study with MRI

    NASA Astrophysics Data System (ADS)

    Ranger, Bryan; Littrup, Peter; Duric, Neb; Li, Cuiping; Schmidt, Steven; Lupinacci, Jessica; Myc, Lukasz; Szczepanski, Amy; Rama, Olsi; Bey-Knight, Lisa

    2010-03-01

    The purpose of this study was to investigate the performance of an ultrasound tomography (UST) prototype relative to magnetic resonance (MR) for imaging overall breast anatomy and accentuating tumors relative to background tissue. The study was HIPAA compliant, approved by the Institutional Review Board, and performed after obtaining the requisite informed consent. Twenty-three patients were imaged with MR and the UST prototype. T1 weighted images with fat saturation, with and without gadolinium enhancement, were used to examine anatomical structures and tumors, while T2 weighted images were used to identify cysts. The UST scans generated sound speed, attenuation, and reflection images. A qualitative visual comparison of the MRI and UST images was then used to identify anatomical similarities. A more focused approach that involved a comparison of reported masses, lesion volumes, and breast density was used to quantify the findings from the visual assessment. Our acoustic tomography prototype imaged distributions of fibrous stroma, parenchyma, fatty tissues, and lesions in patterns similar to those seen in the MR images. The range of thresholds required to establish tumor volume equivalency between MRI and UST suggested that a universal threshold for isolating masses relative to background tissue is feasible with UST. UST has demonstrated the ability to visualize and characterize breast tissues in a manner comparable to MRI. Thresholding techniques accentuate masses relative to background anatomy, which may prove clinically useful for early cancer detection.

  8. Emerging applications for ferumoxytol as a contrast agent in MRI.

    PubMed

    Bashir, Mustafa R; Bhatti, Lubna; Marin, Daniele; Nelson, Rendon C

    2015-04-01

    Ferumoxytol is an ultrasmall superparamagnetic iron oxide (USPIO) agent initially approved by the Food and Drug Administration (FDA) as an iron replacement therapy for patients with anemia due to chronic renal failure. Recently, ferumoxytol has been investigated extensively as an intravenous contrast agent in magnetic resonance imaging (MRI). Since it causes regional T1 and T2 * shortening in vivo, conventional pulse sequences can be used following ferumoxytol administration to demonstrate signal enhancement or loss. Ferumoxytol can be administered as a rapid bolus and has a long intravascular half-life on the order of 14-15 hours, making it a potentially useful agent for vascular and perfusion-weighted MRI. In comparison to other USPIOs, ferumoxytol is less limited by allergic and idiosyncratic reactions. Furthermore, since ferumoxytol is an iron-based agent with no potential for causing nephrogenic systemic fibrosis, it may be useful as an alternative to gadolinium-based contrast agents in patients with compromised renal function. Ferumoxytol is ultimately taken up by macrophages/the reticuloendothelial system in the liver, spleen, and lymph nodes, and this uptake mechanism is being explored as a novel imaging technique for vascular lesions, tumors, and lymph nodes. This article reviews the properties of ferumoxytol relevant to MRI as well as many of the uses for the agent currently under investigation. PMID:24974785

  9. Cell membrane water exchange effects in prostate DCE-MRI

    NASA Astrophysics Data System (ADS)

    Li, Xin; Priest, Ryan A.; Woodward, William J.; Siddiqui, Faisal; Beer, Tomasz M.; Garzotto, Mark G.; Rooney, William D.; Springer, Charles S.

    2012-05-01

    Prostate Dynamic-Contrast-Enhanced (DCE) MRI often exhibits fast and extensive global contrast reagent (CR) extravasation - measured by Ktrans, a pharmacokinetic parameter proportional to its rate. This implies that the CR concentration [CR] is high in the extracellular, extravascular space (EES) during a large portion of the DCE-MRI study. Since CR is detected indirectly, through water proton signal change, the effects of equilibrium transcytolemmal water exchange may be significant in the data and thus should be admitted in DCE-MRI pharmacokinetic modeling. The implications for parameter values were investigated through simulations, and analyses of actual prostate data, with different models. Model parameter correlation and precision were also explored. A near-optimal version of the exchange-sensitized model was found. Our results indicate that ?Ktrans (the Ktrans difference returned by this version and a model assuming exchange to be effectively infinitely fast) may be a very useful biomarker for discriminating malignant from benign prostate tissue. Using an exchange-sensitized model, we find that the mean intracellular water lifetime (?i) - an exchange measure - can be meaningfully mapped for the prostate. Our results show prostate glandular zone differences in ?i values.

  10. PET/MRI assessment of the infarcted mouse heart

    NASA Astrophysics Data System (ADS)

    Buonincontri, Guido; Methner, Carmen; Krieg, Thomas; Hawkes, Robert C.; Adrian Carpenter, T.; Sawiak, Stephen J.

    2014-01-01

    Heart failure originating from myocardial infarction (MI) is a leading cause of death worldwide. Mouse models of ischaemia and reperfusion injury (I/R) are used to study the effects of novel treatment strategies targeting MI, however staging disease and treatment efficacy is a challenge. Damage and recovery can be assessed on the cellular, tissue or whole-organ scale but these are rarely measured in concert. Here, for the first time, we present data showing measures of injury in infarcted mice using complementary techniques for multi-modal characterisation of the heart. We use in vivo magnetic resonance imaging (MRI) to assess heart function with cine-MRI, hindered perfusion with late gadolinium enhancement imaging and muscular function with displacement encoded with stimulated echoes (DENSE) MRI. These measures are followed by positron emission tomography (PET) with 18-F-fluorodeoxyglucose to assess cellular metabolism. We demonstrate a protocol combining each of these measures for the same animal in the same imaging session and compare how the different markers can be used to quantify cardiac recovery on different scales following injury.

  11. Cardiovascular PET/MRI: Challenges and Opportunities.

    PubMed

    LaForest, Richard; Woodard, Pamela K; Gropler, Robert J

    2016-02-01

    Recently, systems combining PET and MRI have appeared on the market. The 2 main advantages of these systems over PET/computed tomography are the improved soft tissue contrast with MRI obtained without ionizing radiation and the potential for simultaneous acquisition of the PET and magnetic resonance images. However, its clinical acceptance has been slow for several reasons. Moreover, there are significant technical challenges that must be overcome from an image acquisition, processing, display, and laboratory workflow perspective for implementing cardiovascular PET/MRI on a routine clinical basis. The potential is high for PET/MRI to become a critical tool in the management of disease. PMID:26590777

  12. SQUID detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-10-03

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  13. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-05-30

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  14. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John (Berkeley, CA); McDermott, Robert (Louisville, CO); Pines, Alexander (Berkeley, CA); Trabesinger, Andreas Heinz (CH-8006 Zurich, CH)

    2007-05-15

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  15. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA); McDermott, Robert F. (Monona, WI); Trabesinger, Andreas H. (London, GB)

    2008-12-16

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  16. Gadolinium-based nanoparticles for theranostic MRI-radiosensitization.

    PubMed

    Lux, François; Sancey, Lucie; Bianchi, Andrea; Crémillieux, Yannick; Roux, Stéphane; Tillement, Olivier

    2015-01-01

    A rapid development of gadolinium-based nanoparticles is observed due to their attractive properties as MRI-positive contrast agents. Indeed, they display high relaxivity, adapted biodistribution and passive uptake in the tumor thanks to enhanced permeability and retention effect. In addition to these imaging properties, it has been recently shown that they can act as effective radiosensitizers under different types of irradiation (radiotherapy, neutron therapy or hadron therapy). These new therapeutic modalities pave the way to therapy guided by imaging and to personalized medicine. PMID:25715316

  17. Tumor Size on Abdominal MRI Versus Pathologic Specimen in Resected Pancreatic Adenocarcinoma: Implications for Radiation Treatment Planning

    SciTech Connect

    Hall, William A.; Mikell, John L.; Winship Cancer Institute, Emory University, Atlanta, Georgia ; Mittal, Pardeep; Colbert, Lauren; Prabhu, Roshan S.; Winship Cancer Institute, Emory University, Atlanta, Georgia ; Kooby, David A.; Winship Cancer Institute, Emory University, Atlanta, Georgia ; Nickleach, Dana; Winship Cancer Institute, Emory University, Atlanta, Georgia ; Hanley, Krisztina; Sarmiento, Juan M.; Ali, Arif N.; Landry, Jerome C.; Winship Cancer Institute, Emory University, Atlanta, Georgia

    2013-05-01

    Purpose: We assessed the accuracy of abdominal magnetic resonance imaging (MRI) for determining tumor size by comparing the preoperative contrast-enhanced T1-weighted gradient echo (3-dimensional [3D] volumetric interpolated breath-hold [VIBE]) MRI tumor size with pathologic specimen size. Methods and Materials: The records of 92 patients who had both preoperative contrast-enhanced 3D VIBE MRI images and detailed pathologic specimen measurements were available for review. Primary tumor size from the MRI was independently measured by a single diagnostic radiologist (P.M.) who was blinded to the pathology reports. Pathologic tumor measurements from gross specimens were obtained from the pathology reports. The maximum dimensions of tumor measured in any plane on the MRI and the gross specimen were compared. The median difference between the pathology sample and the MRI measurements was calculated. A paired t test was conducted to test for differences between the MRI and pathology measurements. The Pearson correlation coefficient was used to measure the association of disparity between the MRI and pathology sizes with the pathology size. Disparities relative to pathology size were also examined and tested for significance using a 1-sample t test. Results: The median patient age was 64.5 years. The primary site was pancreatic head in 81 patients, body in 4, and tail in 7. Three patients were American Joint Commission on Cancer stage IA, 7 stage IB, 21 stage IIA, 58 stage IIB, and 3 stage III. The 3D VIBE MRI underestimated tumor size by a median difference of 4 mm (range, ?34-22 mm). The median largest tumor dimensions on MRI and pathology specimen were 2.65 cm (range, 1.5-9.5 cm) and 3.2 cm (range, 1.3-10 cm), respectively. Conclusions: Contrast-enhanced 3D VIBE MRI underestimates tumor size by 4 mm when compared with pathologic specimen. Advanced abdominal MRI sequences warrant further investigation for radiation therapy planning in pancreatic adenocarcinoma before routine integration into the treatment planning process.

  18. Simple line drawings suffice for functional MRI decoding of natural scene categories

    PubMed Central

    Walther, Dirk B.; Chai, Barry; Caddigan, Eamon; Beck, Diane M.; Fei-Fei, Li

    2011-01-01

    Humans are remarkably efficient at categorizing natural scenes. In fact, scene categories can be decoded from functional MRI (fMRI) data throughout the ventral visual cortex, including the primary visual cortex, the parahippocampal place area (PPA), and the retrosplenial cortex (RSC). Here we ask whether, and where, we can still decode scene category if we reduce the scenes to mere lines. We collected fMRI data while participants viewed photographs and line drawings of beaches, city streets, forests, highways, mountains, and offices. Despite the marked difference in scene statistics, we were able to decode scene category from fMRI data for line drawings just as well as from activity for color photographs, in primary visual cortex through PPA and RSC. Even more remarkably, in PPA and RSC, error patterns for decoding from line drawings were very similar to those from color photographs. These data suggest that, in these regions, the information used to distinguish scene category is similar for line drawings and photographs. To determine the relative contributions of local and global structure to the human ability to categorize scenes, we selectively removed long or short contours from the line drawings. In a category-matching task, participants performed significantly worse when long contours were removed than when short contours were removed. We conclude that global scene structure, which is preserved in line drawings, plays an integral part in representing scene categories. PMID:21593417

  19. Plaque characterization in ex vivo MRI evaluated by dense 3D correspondence with histology

    NASA Astrophysics Data System (ADS)

    van Engelen, Arna; de Bruijne, Marleen; Klein, Stefan; Verhagen, Hence; Groen, Harald; Wentzel, Jolanda; van der Lugt, Aad; Niessen, Wiro

    2011-03-01

    Automatic quantification of carotid artery plaque composition is important in the development of methods that distinguish vulnerable from stable plaques. MRI has shown to be capable of imaging different components noninvasively. We present a new plaque classification method which uses 3D registration of histology data with ex vivo MRI data, using non-rigid registration, both for training and evaluation. This is more objective than previously presented methods, as it eliminates selection bias that is introduced when 2D MRI slices are manually matched to histological slices before evaluation. Histological slices of human atherosclerotic plaques were manually segmented into necrotic core, fibrous tissue and calcification. Classification of these three components was voxelwise evaluated. As features the intensity, gradient magnitude and Laplacian in four MRI sequences after different degrees of Gaussian smoothing, and the distances to the lumen and the outer vessel wall, were used. Performance of linear and quadratic discriminant classifiers for different combinations of features was evaluated. Best accuracy (72.5 +/- 7.7%) was reached with the linear classifier when all features were used. Although this was only a minor improvement to the accuracy of a classifier that only included the intensities and distance features (71.6 +/- 7.9%), the difference was statistically significant (paired t-test, p<0.05). Good sensitivity and specificity for calcification was reached (83% and 95% respectively), however, differentiation between fibrous (sensitivity 85%, specificity 60%) and necrotic tissue (sensitivity 49%, specificity 89%) was more difficult.

  20. Daniel L. Schacter: Award for Distinguished Scientific Contributions

    ERIC Educational Resources Information Center

    American Psychologist, 2012

    2012-01-01

    Presents Daniel L. Schacter as one of the winners of the American Psychological Association's Award for Distinguished Scientific Contributions (2012). Daniel L. Schacter's major theoretical and empirical contributions include groundbreaking research on the psychological and neural foundations of implicit and explicit memory, memory distortions and…

  1. The Hues of English. NCTE Distinguished Lectures 1969.

    ERIC Educational Resources Information Center

    National Council of Teachers of English, Champaign, IL.

    The third volume in the NCTE Distinguished Lectures Series, this collection of papers includes (1) William Stafford on poetry and the language of everyday life, (2) Fred Stocking linking Shakespeare to his time and all time by analysing "temperance" in Sonnet 18, (3) Alan Downer discussing the nature of comedy in drama and the universal search for…

  2. A Conceptual and Psychometric Framework for Distinguishing Categories and Dimensions

    ERIC Educational Resources Information Center

    De Boeck, Paul; Wilson, Mark; Acton, G. Scott

    2005-01-01

    An important, sometimes controversial feature of all psychological phenomena is whether they are categorical or dimensional. A conceptual and psychometric framework is described for distinguishing whether the latent structure behind manifest categories (e.g., psychiatric diagnoses, attitude groups, or stages of development) is category-like or…

  3. E. Mavis Hetherington: Award for Distinguished Scientific Contributions

    ERIC Educational Resources Information Center

    American Psychologist, 2004

    2004-01-01

    Provides the biography of E. Mavis Hetherington and announces that she has received the APA Award for Distinguished Scientific Contributions (2004) for her outstanding contributions to understanding the family context of children's and adolescents' development and adaptation. A selected bibliography is also provided.

  4. List Distinguishing Parameters of Trees Michael Ferrara1,2

    E-print Network

    Hartke, Stephen

    List Distinguishing Parameters of Trees Michael Ferrara1,2 , Ellen Gethner3 , Stephen G. Hartke4 of Colorado Denver, Denver, CO 80217. {michael.ferrara;paul.wenger@ucdenver.edu} 2 Research supported in part, Rochester Institute of Technology, Rochester, NY 14623. paul.wenger@mail.rit.edu 1 #12;Collins [1

  5. Recent Detrimental and Distinguished Books about Hispanic People and Cultures.

    ERIC Educational Resources Information Center

    Schon, Isabel

    1981-01-01

    The article discusses nine detrimental and six distinguished books about Hispanic people and cultures, published since 1979 for young readers. It is suggested that many recent books that depict Hispanic people and cultures repeat the same stereotypes, misconceptions and insensibilities that were prevalent in books published in the 1960s and early…

  6. Michael J. Meaney: Award for Distinguished Scientific Contributions

    ERIC Educational Resources Information Center

    American Psychologist, 2012

    2012-01-01

    Presents Michael J. Meaney as one of the winners of the American Psychological Association's Award for Distinguished Scientific Contributions (2012). Michael J. Meaney has taken the phenomenon of "handling" of newborn rats and opened a new area of investigation that has given new meaning to epigenetics via his work demonstrating transgenerational…

  7. Distinguishing Text from Graphics in On-line Handwritten Ink

    E-print Network

    Bishop, Christopher M.

    Distinguishing Text from Graphics in On-line Handwritten Ink Christopher M. Bishop, Markus Svens in handwritten digital ink. It utilizes not just the characteristics of the strokes, but also the information pro digital ink, collected using a Tablet PC. 1 Introduction Pen controlled computing devices such as PDAs

  8. Optimal amount of entanglement to distinguish quantum states instantaneously

    NASA Astrophysics Data System (ADS)

    Groisman, Berry; Strelchuk, Sergii

    2015-11-01

    We introduce an aspect of nonlocality which arises when the task of quantum states distinguishability is considered under local operations and shared entanglement in the absence of classical communication. We find the optimal amount of entanglement required to accomplish the task perfectly for sets of orthogonal states and argue that it quantifies information nonlocality.

  9. Kelly D. Brownell: Award for Distinguished Scientific Applications of Psychology

    ERIC Educational Resources Information Center

    American Psychologist, 2012

    2012-01-01

    Presents a short biography of Kelly D. Brownwell, winner of the American Psychological Association's Award for Distinguished Scientific Applications of Psychology (2012). He won the award for outstanding contributions to our understanding of the etiology and management of obesity and the crisis it poses for the modern world. A seminal thinker in…

  10. Oklahoma National Distinguished Principals: A Case Study of Leadership Practices

    ERIC Educational Resources Information Center

    Jones, Toni Rae

    2010-01-01

    Purpose, scope, and method of study: The purpose of this study was to examine the daily leadership practices of Oklahoma National Distinguished Principals to better understand how leadership performance is used to create and sustain productive change within schools. This qualitative study relied on a multiple case design utilizing participants…

  11. A Theoretical Study of Kolmogorov-Smirnov Distinguishers

    E-print Network

    Rioul, Olivier

    ) and derive conclusions for any kind of data. Annelie Heuser is Google European fellow in the field of privacy introduced to quantify the efficiency of attacks: success rate and guess- ing entropy. In [10] Maghrebi et al. introduced error bars on the success rate in order to determine a reliable decision whether one distinguisher

  12. A Theoretical Study of Kolmogorov-Smirnov Distinguishers

    E-print Network

    International Association for Cryptologic Research (IACR)

    ) and the impact of the leakage model) and derive conclusions for any kind of data. Annelie Heuser is Google the efficiency of attacks: success rate and guessing entropy. In [10] Maghrebi et al. introduced error bars on the success rate in order to determine a reliable decision whether one distinguisher is better than another

  13. Distinguishing between Dirac and Majorana neutrinos withtwo-particle interferometry

    SciTech Connect

    Gutierrez, Thomas D.

    2006-03-02

    Two-particle interferometry, a second-order interferenceeffect, is explored as another possible tool to distinguish betweenmassive Dirac and Majorana neutrinos. A simple theoretical framework isdiscussed in the context of several gedanken experiments. The method canin principle provide both the mass scale and the quantum nature of theneutrino for a certain class of incoherent left-handed sourcecurrents.

  14. Award for Distinguished Scientific Contributions: Susan E. Carey

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    Susan E. Carey, winner of the 2009 Award for Distinguished Scientific Contributions, is cited for groundbreaking studies of the nature of concepts and conceptual change. Her research deepens understanding of the development of concepts, and of the belief systems in which they are embedded, over human childhood, over the history of science, and…

  15. Award for Distinguished Scientific Applications of Psychology: Nancy E. Adler

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    Nancy E. Adler, winner of the Award for Distinguished Scientific Applications of Psychology, is cited for her research on reproductive health examining adolescent decision making with regard to contraception, conscious and preconscious motivations for pregnancy, and perception of risk for sexually transmitted diseases, and for her groundbreaking…

  16. Edward F. Diener: Award for Distinguished Scientific Contributions

    ERIC Educational Resources Information Center

    American Psychologist, 2012

    2012-01-01

    Presents Edward F. Diener as one of the winners of the American Psychological Association's Award for Distinguished Scientific Contributions (2012). Edward F. Diener has been a leader in every aspect of well-being research. He provided an influential conception of well-being as consisting of cognitive and emotional elements. A citation, biography,…

  17. Henderson Receives ISBER Distinguished Leadership and Service Award

    Cancer.gov

    In May 2015, Marianne K. Henderson, M.S., CPC, Senior Advisor for Division Resources, received the Distinguished Leadership and Service Award from the International Society for Biological and Environmental Repositories (ISBER), the leading international forum for addressing the technical, legal, ethical, and managerial issues relevant to repositories of biologic and environmental specimens.

  18. DCEG Distinguished Lecturer - Dame Valerie Beral, M.D.

    Cancer.gov

    Dame Valerie Beral, M.D. is the 2014 recipient of the NCI Rosalind Franklin Award, which she will receive at the NCI Intramural Scientific Investigators Retreat. Dr. Beral has extended her visit in order to come to NCI Shady Grove to spend a day with her collaborators. As a DCEG Distinguished Lecturer she will present a short talk about her career in epidemiology.

  19. Distinguishing between Poor/Dysfunctional Parenting and Child Emotional Maltreatment

    ERIC Educational Resources Information Center

    Wolfe, David A.; McIsaac, Caroline

    2011-01-01

    Objective: This paper was intended to distinguish between poor parenting and child emotional maltreatment (CEM), to inform child welfare and public health policymakers of the need for differentiated responses. Methods: Scientific literature was integrated with current practice and assumptions relating to poor/dysfunctional parenting and child…

  20. 2010 Society of Petroleum Engineers John Franklin Carll Distinguished

    E-print Network

    Zhou, Chongwu

    2010 Society of Petroleum Engineers John Franklin Carll Distinguished Professional Award Iraj Ershaghi Holder of the Omar B. Milligan Chair in Petroleum Engineering in the Mork Family Department renowned researcher and educator in advanced computer-aided `smart' oil well tech- nology, will receive

  1. Martin E. P. Seligman: 2006 award for distinguished scientific contributions.

    PubMed

    2006-11-01

    Presents the citation for Martin E. P. Seligman, who received the Award for Distinguished Scientific Contributions "for a career spent charging creatively ahead of his field and then pulling his colleagues along." A brief profile and a selected bibliography, as well as the award address, Positive Psychotherapy, accompany the citation. ((c) 2006 APA, all rights reserved). PMID:17115809

  2. How can we distinguish transient pulsars from SETI beacons?

    E-print Network

    Benford, James

    2010-01-01

    How would observers differentiate Beacons from pulsars or other exotic sources, in light of likely Beacon observables? Bandwidth, pulse width and frequency may be distinguishing features. Such transients could be evidence of civilizations slightly higher than ourselves on the Kardashev scale.

  3. Award for Distinguished Scientific Contributions: Alice H. Eagly

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    Alice H. Eagly, winner of the Award for Distinguished Scientific Contributions, is cited for her work in the field of social psychology, the psychology of gender, and the use of meta-analytic techniques. She envisions a psychology that extends from individual cognitions to societal structures. In addition to the citation, a biography and selected…

  4. Can Assertiveness be Distinguished From Aggressiveness Using Self Report Data?

    ERIC Educational Resources Information Center

    Mauger, Paul A.; And Others

    The differences between aggressiveness and assertiveness were examined using the Interpersonal Behavior Survey (IBS), a 136-item self-report questionnaire which was developed to distinguish between assertive and aggressive behaviors. Item level factor analysis was used in scale construction. Results indicated that: (1) the correlation between the…

  5. The Identification of Conductor-Distinguished Functions of Conducting

    ERIC Educational Resources Information Center

    Gumm, Alan J.; Battersby, Sharyn L.; Simon, Kathryn L.; Shankles, Andrew E.

    2011-01-01

    The purpose of the present study was to identify whether conductors distinguish functions of conducting similarly to functions implied in previous research. A sample of 84 conductors with a full range of experience levels (M = 9.8) and of a full range of large ensemble types and ensemble age levels rated how much they pay attention to 82…

  6. Brief Genetics Report Distinguishing Covariation From Causation in Diabetes

    E-print Network

    Yandell, Brian S.

    Brief Genetics Report Distinguishing Covariation From Causation in Diabetes A Lesson From-induced diabetes. We found that Pdi mRNA is 20-fold more abundant in the diabetes-susceptible BTBR mouse strain relative to the diabetes-resistant C56BL/6 (B6) strain. A genetic analysis was carried out to determine

  7. Award for Distinguished Scientific Contributions: Steven F. Maier

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    Steven F. Maier, winner of the Award for Distinguished Scientific Contributions, is cited for his work in the fields of learned helplessness; cytokines, depressed mood, and cognitive interference; and the brain structures that produce and counteract learned helplessness. In addition to the citation, a biography and selected bibliography of Maier's…

  8. A Tribute to My Ag Teacher: 2011 AAAE Distinguished Lecture

    ERIC Educational Resources Information Center

    Barrick, R. Kirby

    2012-01-01

    The author is a product of school-based agricultural education. In a way, this distinguished lecture could also be called a tribute to his high school ag teacher, John Stimpert. Mr. Stimpert was a true professional and an excellent teacher. He changed and he changed the program with the changing school and community. The more the author became…

  9. Distinguishing Protein-Coding from Non-Coding RNAs

    E-print Network

    Gough, Julian

    Distinguishing Protein-Coding from Non-Coding RNAs through Support Vector Machines Jinfeng Liu1, Japan RIKEN's FANTOM project has revealed many previously unknown coding sequences, as well more transcripts that do not code for proteins have been identified by transcriptome studies

  10. Coherent State Distinguishability in Continuous Variable Quantum Cryptography

    E-print Network

    Christian Weedbrook; Mile Gu; Andrew M. Lance; Thomas Symul; Ping Koy Lam; Timothy C. Ralph

    2007-03-15

    We use the probability of error as a measure of distinguishability between two pure and two mixed symmetric coherent states in the context of continuous variable quantum cryptography. We show that the two mixed symmetric coherent states (in which the various components have the same real part) never give an eavesdropper more information than two pure coherent states.

  11. New method for predicting estrogen receptor status utilizing breast MRI texture kinetic analysis

    NASA Astrophysics Data System (ADS)

    Chaudhury, Baishali; Hall, Lawrence O.; Goldgof, Dmitry B.; Gatenby, Robert A.; Gillies, Robert; Drukteinis, Jennifer S.

    2014-03-01

    Magnetic Resonance Imaging (MRI) of breast cancer typically shows that tumors are heterogeneous with spatial variations in blood flow and cell density. Here, we examine the potential link between clinical tumor imaging and the underlying evolutionary dynamics behind heterogeneity in the cellular expression of estrogen receptors (ER) in breast cancer. We assume, in an evolutionary environment, that ER expression will only occur in the presence of significant concentrations of estrogen, which is delivered via the blood stream. Thus, we hypothesize, the expression of ER in breast cancer cells will correlate with blood flow on gadolinium enhanced breast MRI. To test this hypothesis, we performed quantitative analysis of blood flow on dynamic contrast enhanced MRI (DCE-MRI) and correlated it with the ER status of the tumor. Here we present our analytic methods, which utilize a novel algorithm to analyze 20 volumetric DCE-MRI breast cancer tumors. The algorithm generates post initial enhancement (PIE) maps from DCE-MRI and then performs texture features extraction from the PIE map, feature selection, and finally classification of tumors into ER positive and ER negative status. The combined gray level co-occurrence matrices, gray level run length matrices and local binary pattern histogram features allow quantification of breast tumor heterogeneity. The algorithm predicted ER expression with an accuracy of 85% using a Naive Bayes classifier in leave-one-out cross-validation. Hence, we conclude that our data supports the hypothesis that imaging characteristics can, through application of evolutionary principles, provide insights into the cellular and molecular properties of cancer cells.

  12. Automatic Articular Cartilage Segmentation Based on Pattern Recognition from Knee MRI Images.

    PubMed

    Pang, Jianfei; Li, PengYue; Qiu, Mingguo; Chen, Wei; Qiao, Liang

    2015-12-01

    An automatic method for cartilage segmentation using knee MRI images is described. Three binary classifiers with integral and partial pixel features are built using the Bayesian theorem to segment the femoral cartilage, tibial cartilage and patellar cartilage separately. First, an iterative procedure based on the feedback of the number of strong edges is designed to obtain an appropriate threshold for the Canny operator and to extract the bone-cartilage interface from MRI images. Second, the different edges are identified based on certain features, which allow for different cartilage to be distinguished synchronously. The cartilage is segmented preliminarily with minimum error Bayesian classifiers that have been previously trained. According to the cartilage edge and its anatomic location, the speed of segmentation is improved. Finally, morphological operations are used to improve the primary segmentation results. The cartilage edge is smooth in the automatic segmentation results and shows good consistency with manual segmentation results. The mean Dice similarity coefficient is 0.761. PMID:25700618

  13. Evolution of imaging in rectal cancer: multimodality imaging with MDCT, MRI, and PET

    PubMed Central

    Chen, Yifei; Fishman, Elliot K.

    2015-01-01

    Magnetic resonance imaging (MRI), multidetector computed tomography (MDCT), and positron emission tomography (PET) are complementary imaging modalities in the preoperative staging of patients with rectal cancer, and each offers their own individual strengths and weaknesses. MRI is the best available radiologic modality for the local staging of rectal cancers, and can play an important role in accurately distinguishing which patients should receive preoperative chemoradiation prior to total mesorectal excision. Alternatively, both MDCT and PET are considered primary modalities when performing preoperative distant staging, but are limited in their ability to locally stage rectal malignancies. This review details the role of each of these three modalities in rectal cancer staging, and how the three imaging modalities can be used in conjunction. PMID:25830037

  14. MRI: update on technology diffusion and acquisition.

    PubMed

    Hoppszallern, S; Hughes, C; Zimmerman, R A

    1991-04-01

    Over the past three years, magnetic resonance imaging (MRI) has become accepted as a valuable diagnostic tool, and its applications continue to expand. During this time, the number of units installed in the United States doubled. By 1990 about 2,000 MRI units were in place in the United States and nearly 20 percent of the MRI-installed base was mobile, according to a research study conducted by the Hadley Hart Group (Chicago) and Drew Consultants, Inc. (Concord, MA). With the introduction of the prospective payment system, many hospitals were hesitant to spend limited capital on new technology, such as MRI. At the same time, freestanding diagnostic imaging centers were on the rise. Some hospitals and entrepreneurs who foresaw the potential of MRI in health care pioneered its use in the clinical setting. Hospitals began to examine new partnership arrangements and alternative forms of financing, so that they too could offer MRI services. By the end of 1988, the majority of hospitals offering MRI services did not own their own unit and about 40 percent of the hospitals offering MRI services were in a mobile configuration according to the Hadley Hart Group. While the technology has been diffused into 100-bed hospitals via mobile service vendors in some parts of the country, many medium-sized and large hospitals also have entered the MRI services market in this fashion. In the larger hospitals, the patient demand or need for the service often would justify acquisition of MRI, but the expense of the technology, and in many areas restrictive state health planning policies, modified purchase of MRI systems by hospitals. Mobile service vendors offered hospitals a way to startup MRI services in a limited fashion without a major capital expenditure and its associated risk. As hospitals gain experience with mobile MRI and achieve or exceed their early utilization projections, administrators are reevaluating the need to expand services to a full-time fixed site. Early fixed-site MRI providers have been constantly upgrading their MRI capability while planning on adding more units. The technology itself has continued to improve, primarily through the implementation of new software that permits new techniques such as MR angiography (MRA) to be performed. Units are available in a wide price range, price usually reflecting both the field strength (0.5 tesla units cost less) as well as the additional capabilities beyond routine imaging (MRA, spectroscopy).(ABSTRACT TRUNCATED AT 400 WORDS) PMID:10110923

  15. Novel Imaging of Prostate Cancer with MRI, MRI/US, and PET.

    PubMed

    Koo, Phillip J; Kwak, Jennifer J; Pokharel, Sajal; Choyke, Peter L

    2015-12-01

    Imaging of prostate cancer presents many challenges to the imaging community. There has been much progress in this space in large part due to MRI and PET radiopharmaceuticals. Though MRI has been focused on the evaluation of local disease and PET on the detection of metastatic disease, these two areas do converge and will be complementary especially with the growth of new PET/MRI technologies. In this review article, we review novel MRI, MRI/US, and PET radiopharmaceuticals which will offer insight into the future direction of imaging in prostate cancer. PMID:26462919

  16. MRI and FDG PET/CT Imaging Manifestations of Cardiac Sarcoidosis.

    PubMed

    Lu, Yang; Sweiss, Nadera J

    2015-12-01

    A 52-year-old man had biopsy-proven sarcoidosis of mediastinal lymph nodes. Cardiac sarcoidosis was confirmed on cardiac MRI with typical imaging features as delayed gadolinium enhancement. Follow-up FDG PET/CT with a 3-day pretest diet modification showed suppression of overall myocardial uptake of FDG but with multifocal abnormal FDG uptake in the myocardium regions corresponding to the previous MRI findings. Additional noncardiac active sarcoidosis involving multiple organ and lymph nodes were also visualized on FDG PET/CT. PMID:26544904

  17. Pantopaque simulating thrombosed intracranial aneurysms on MRI

    SciTech Connect

    Lidov, M.W.; Silvers, A.R.; Mosesson, R.E.; Stollman, A.L.; Som, P.M.

    1996-03-01

    A patient is presented in whom iophendylate (Pantopaque) within the basal cisterns closely resembled the appearance on MRI of thrombosed aneurysms of the middle cerebral arteries. The sometimes subtle differences between the appearances on MRI of Pantopaque and aneurysmal clot are discussed to permit accurate diagnosis without resorting to more invasive diagnostic tests, such as cerebral angiography. 5 refs., 4 figs.

  18. MRI endoscopy using intrinsically localized probes

    PubMed Central

    Sathyanarayana, Shashank; Bottomley, Paul A.

    2009-01-01

    Magnetic resonance imaging (MRI) is traditionally performed with fixed externally applied gradient magnetic fields and is hence intrinsically locked to the laboratory frame of reference (FoR). Here a method for high-resolution MRI that employs active, catheter-based, tiny internal probes that utilize the spatial properties of the probe itself for localization is proposed and demonstrated at 3 T. Because these properties are intrinsic to the probe, they move with it, transforming MRI from the laboratory FoR to the FoR of the device itself, analogous to an endoscope. The “MRI endoscope” can utilize loop coils and loopless antennas with modified sensitivity, in combination with adiabatic excitation by the device itself, to restrict the MRI sensitivity to a disk-shaped plane a few mm thick. Excitation with the MRI endoscope limits the eddy currents induced in the sample to an excited volume whose size is orders of magnitude below that excited by a conventional body MRI coil. Heat testing shows maximum local temperature increases of <1 °C during MRI, within regulatory guidelines. The method is demonstrated in a kiwifruit, in intact porcine and rabbit aortas, and in an atherosclerotic human iliac artery specimen, with in-plane resolution as small as 80 ?m and 1.5–5 mm slice thickness. PMID:19378751

  19. Pantopaque simulating thrombosed intracranial aneurysms on MRI.

    PubMed

    Lidov, M W; Silvers, A R; Mosesson, R E; Stollman, A L; Som, P M

    1996-01-01

    A patient is presented in whom iophendylate (Pantopaque) within the basal cisterns closely resembled the appearance on MRI of thrombosed aneurysms of the middle cerebral arteries. The sometimes subtle differences between the appearances on MRI of Pantopaque and aneurysmal clot are discussed to permit accurate diagnosis without resorting to more invasive diagnostic tests, such as cerebral angiography. PMID:8606227

  20. Modeling White Matter MRI Scan Parameters

    E-print Network

    Leahy, Richard M.

    Modeling White Matter MRI Scan Parameters http://resource.loni.usc.edu Mapping Changes in White Matter Microstructure throughout Development K. Lynch & K. Clark Introduction Methods Results Discussion References · Imaging and behavioral data comes from the C-MIND (Cincinnati MRI Imaging of Neurodevelopment

  1. Gd(III)-nanodiamond conjugates for MRI contrast enhancement

    PubMed Central

    Manus, Lisa M.; Mastarone, Daniel J.; Waters, Emily A.; Zhang, Xue-Qing; Schultz-Sikma, Elise A.; MacRenaris, Keith W.; Ho, Dean

    2010-01-01

    A Gd(III)-nanodiamond conjugate [Gd(III)-ND] was prepared and characterized, enabling detection of nanodiamonds by MR imaging. The Gd(III)-ND particles significantly reduced the T1 of water protons with a per-Gd(III) relaxivity of 58.82 ± 1.18 mM?1s?1 at 1.5 Tesla (60 MHz). This represents a tenfold increase compared to the monomer Gd(III) complex (r1 = 5.42 ± 0.20 mM?1s?1) and is among the highest per-Gd(III) relaxivities reported. PMID:20038088

  2. Residual analysis of the water resonance signal in breast lesions imaged with high spectral and spatial resolution (HiSS) MRI: A pilot study

    SciTech Connect

    Weiss, William A. Medved, Milica; Karczmar, Gregory S.; Giger, Maryellen L.

    2014-01-15

    Purpose: High spectral and spatial resolution magnetic resonance imaging (HiSS MRI) yields information on the local environment of suspicious lesions. Previous work has demonstrated the advantages of HiSS (complete fat-suppression, improved image contrast, no required contrast agent, etc.), leading to initial investigations of water resonance lineshape for the purpose of breast lesion classification. The purpose of this study is to investigate a quantitative imaging biomarker, which characterizes non-Lorentzian components of the water resonance in HiSS MRI datasets, for computer-aided diagnosis (CADx). Methods: The inhomogeneous broadening and non-Lorentzian or “off-peak” components seen in the water resonance of proton spectra of breast HiSS images are analyzed by subtracting a Lorentzian fit from the water peak spectra and evaluating the difference spectrum or “residual.” The maxima of these residuals (referred to hereafter as “off-peak components”) tend to be larger in magnitude in malignant lesions, indicating increased broadening in malignant lesions. The authors considered only those voxels with the highest magnitude off-peak components in each lesion, with the number of selected voxels dependent on lesion size. Our voxel-based method compared the magnitudes and frequencies of off-peak components of all voxels from all lesions in a database that included 15 malignant and 8 benign lesions (yielding ?3900 voxels) based on the lesions’ biopsy-confirmed diagnosis. Lesion classification was accomplished by comparing the average off-peak component magnitudes and frequencies in malignant and benign lesions. The area under the ROC curve (AUC) was used as a figure of merit for both the voxel-based and lesion-based methods. Results: In the voxel-based task of distinguishing voxels from malignant and benign lesions, off-peak magnitude yielded an AUC of 0.88 (95% confidence interval [0.84, 0.91]). In the lesion-based task of distinguishing malignant and benign lesions, average off-peak magnitude yielded an AUC 0.83 (95% confidence interval [0.61, 0.98]). Conclusions: These promising AUC values suggest that analysis of the water-resonance in each HiSS image voxel using “residual analysis” could have high diagnostic utility and could be used to enhance current CADx methods and allow detection of breast cancer without the need to inject contrast agents.

  3. Robotic System for MRI-Guided Stereotactic Neurosurgery

    PubMed Central

    Li, Gang; Cole, Gregory A.; Shang, Weijian; Harrington, Kevin; Camilo, Alex; Pilitsis, Julie G.; Fischer, Gregory S.

    2015-01-01

    Stereotaxy is a neurosurgical technique that can take several hours to reach a specific target, typically utilizing a mechanical frame and guided by preoperative imaging. An error in any one of the numerous steps or deviations of the target anatomy from the preoperative plan such as brain shift (up to 20 mm), may affect the targeting accuracy and thus the treatment effectiveness. Moreover, because the procedure is typically performed through a small burr hole opening in the skull that prevents tissue visualization, the intervention is basically “blind” for the operator with limited means of intraoperative confirmation that may result in reduced accuracy and safety. The presented system is intended to address the clinical needs for enhanced efficiency, accuracy, and safety of image-guided stereotactic neurosurgery for Deep Brain Stimulation (DBS) lead placement. The work describes a magnetic resonance imaging (MRI)-guided, robotically actuated stereotactic neural intervention system for deep brain stimulation procedure, which offers the potential of reducing procedure duration while improving targeting accuracy and enhancing safety. This is achieved through simultaneous robotic manipulation of the instrument and interactively updated in situ MRI guidance that enables visualization of the anatomy and interventional instrument. During simultaneous actuation and imaging, the system has demonstrated less than 15% signal-to-noise ratio (SNR) variation and less than 0.20% geometric distortion artifact without affecting the imaging usability to visualize and guide the procedure. Optical tracking and MRI phantom experiments streamline the clinical workflow of the prototype system, corroborating targeting accuracy with 3-axis root mean square error 1.38 ± 0.45 mm in tip position and 2.03 ± 0.58° in insertion angle. PMID:25376035

  4. Optimal Brain MRI Protocol for New Neurological Complaint

    PubMed Central

    Mehan, William A.; González, R. Gilberto; Buchbinder, Bradley R.; Chen, John W.; Copen, William A.; Gupta, Rajiv; Hirsch, Joshua A.; Hunter, George J.; Hunter, Scott; Johnson, Jason M.; Kelly, Hillary R.; Larvie, Mykol; Lev, Michael H.; Pomerantz, Stuart R.; Rapalino, Otto; Rincon, Sandra; Romero, Javier M.; Schaefer, Pamela W.; Shah, Vinil

    2014-01-01

    Background/Purpose Patients with neurologic complaints are imaged with MRI protocols that may include many pulse sequences. It has not been documented which sequences are essential. We assessed the diagnostic accuracy of a limited number of sequences in patients with new neurologic complaints. Methods 996 consecutive brain MRI studies from patients with new neurological complaints were divided into 2 groups. In group 1, reviewers used a 3-sequence set that included sagittal T1-weighted, axial T2-weighted fluid-attenuated inversion recovery, and axial diffusion-weighted images. Subsequently, another group of studies were reviewed using axial susceptibility-weighted images in addition to the 3 sequences. The reference standard was the study's official report. Discrepancies between the limited sequence review and the reference standard including Level I findings (that may require immediate change in patient management) were identified. Results There were 84 major findings in 497 studies in group 1 with 21 not identified in the limited sequence evaluations: 12 enhancing lesions and 3 vascular abnormalities identified on MR angiography. The 3-sequence set did not reveal microhemorrhagic foci in 15 of 19 studies. There were 117 major findings in 499 studies in group 2 with 19 not identified on the 4-sequence set: 17 enhancing lesions and 2 vascular lesions identified on angiography. All 87 Level I findings were identified using limited sequence (56 acute infarcts, 16 hemorrhages, and 15 mass lesions). Conclusion A 4-pulse sequence brain MRI study is sufficient to evaluate patients with a new neurological complaint except when contrast or angiography is indicated. PMID:25343371

  5. Automated identification of spinal cord and vertebras on sagittal MRI

    NASA Astrophysics Data System (ADS)

    Zhou, Chuan; Chan, Heang-Ping; Dong, Qian; He, Bo; Wei, Jun; Hadjiiski, Lubomir M.; Couriel, Daniel

    2014-03-01

    We are developing an automated method for the identification of the spinal cord and the vertebras on spinal MR images, which is an essential step for computerized analysis of bone marrow diseases. The spinal cord segment was first enhanced by a newly developed hierarchical multiscale tubular (HMT) filter that utilizes the complementary hyper- and hypo- intensities in the T1-weighted (T1W) and STIR MRI sequences. An Expectation-Maximization (EM) analysis method was then applied to the enhanced tubular structures to extract candidates of the spinal cord. The spinal cord was finally identified by a maximum-likelihood registration method by analysis of the features extracted from the candidate objects in the two MRI sequences. Using the identified spinal cord as a reference, the vertebras were localized based on the intervertebral disc locations extracted by another HMT filter applied to the T1W images. In this study, 5 and 30 MRI scans from 35 patients who were diagnosed with multiple myeloma disease were collected retrospectively with IRB approval as training and test set, respectively. The vertebras manually outlined by a radiologist were used as reference standard. A total of 422 vertebras were marked in the 30 test cases. For the 30 test cases, 100% (30/30) of the spinal cords were correctly segmented with 4 false positives (FPs) mistakenly identified on the back muscles in 4 scans. A sensitivity of 95.0% (401/422) was achieved for the identification of vertebras, and 5 FPs were marked in 4 scans with an average FP rate of 0.17 FPs/scan.

  6. Permanent magnet-based MRI

    NASA Astrophysics Data System (ADS)

    Cole, David Mitchell

    1997-10-01

    The principal goal of this project is to design and build a low-cost, imaging quality permanent magnet, together with the requisite shim, gradient, and radiofrequency coils, and to integrate the magnet with an existing imaging station. There are commercial products presently available that are very similar to this imager, but information about these products is proprietary. We present here all of the details concerning the design and the manufacturing process for constructing the permanent magnet, and include suggestions for improvement. Specifically, the prototype has a mass of about 150 kilograms and is therefore portable. It's C-type geometry allows maximum access to the imaging region, which is an oblate sphere about 0.5 inches in diameter centered in a 4.7 inch air gap between two seven-inch diameter polefaces. It is hoped that this imaging magnet will serve as the prototype for a series of larger versions that will be clinically useful and affordable to physicians in developing nations. To this end, scientists in the United States and Mexico have begun to collaborate with the intention to create an MRI institute in Mexico that will train new students in this discipline, and fabricate improved imagers. The prototype resulting from this work will seed the creation of this institute, and is intended to entice students into the study of MRI by enabling hands-on interaction with an otherwise prohibitively expensive instrument.

  7. Distinguishability of biological material by use of ultraviolet multispectral fluorescence

    SciTech Connect

    Gray, P.C.; Shokair, I.R.; Rosenthal, S.E.; Tisone, G.C.; Wagner, J.S.; Rigdon, L.D.; Siragusa, G.R.; Heinen, R.J.

    1998-09-01

    Recent interest in the detection and analysis of biological samples by spectroscopic methods has led to questions concerning the degree of distinguishability and biological variability of the UV fluorescent spectra from such complex samples. We show that the degree of distinguishability of such spectra is readily determined numerically. As a practical example of this technique, we show its application to the analysis of UV fluorescence spectra taken of {ital E. coli}, {ital S. aureus}, and {ital S. typhimurium}. The use of this analysis to determine the degree of biological variability and also to verify that measurements are being made in a linear regime in which analytic methods such as multivariate analysis are valid is discussed. {copyright} 1998 Optical Society of America

  8. Any 2 x n subspace is locally distinguishable

    SciTech Connect

    Yu Nengkun; Duan Runyao; Ying Mingsheng

    2011-07-15

    A subspace of a multipartite Hilbert space is said to be locally indistinguishable if any orthonormal basis of this subspace cannot be perfectly distinguished by local operations and classical communication. Previously it was shown that any m x n bipartite system with m>2 and n>2 has a locally indistinguishable subspace. However, it has been an open problem since 2005 whether there is a locally indistinguishable bipartite subspace with a qubit subsystem. We settle this problem in negative by showing that any 2 x n bipartite subspace contains a basis that is locally distinguishable. As an interesting application, we show that any quantum channel with two Kraus operators has optimal environment-assisted classical capacity.

  9. Distinguishing graphs with a quantum annealer using susceptibility measurements

    NASA Astrophysics Data System (ADS)

    Wittmann, Matthew; Hen, Itay; Young, A. P.

    2014-03-01

    Recently it has been proposed that the Graph Isomorphism (GI) problem could be solved using a quantum annealer. This is done by encoding the graphs into Ising Hamiltonians, identifying the vertices with spins and the edges with antiferromagnetic interactions. The idea is that measurements of simple observables during and at the end of the annealing process should distinguish non-isomorphic graphs. The first experimental study of the GI problem using D-Wave's quantum computer has been carried out by Vinci et al., utilizing measurements taken at the end of the annealing process. Here, we will present preliminary evidence that measurements taken part way through the annealing process, now obtainable using state-of-the-art devices, may offer better distinguishing capabilities.

  10. Award for Distinguished Contributions to Education and Training in Psychology.

    PubMed

    2015-11-01

    The 2015 recipients of the APA Education and Training Contributions Awards were selected by the 2014 Education and Training Awards Committee appointed by the Board of Educational Affairs (BEA). The Award for Distinguished Contributions to Education and Training in Psychology is given by the BEA in recognition of the efforts of psychologists who have made distinguished contributions to education and training, who have produced imaginative innovations, or who have been involved in the developmental phases of programs in education and training in psychology. The Career designation is added to the award at the discretion of the Education and Training Awards Committee to recognize continuous significant contributions made over a lifelong career in psychology. This year the Education and Training Awards Committee selected a psychologist for the Career designation: Rodney K. Goodyear. Names of the winners from 1987 through 2015 are provided. (PsycINFO Database Record PMID:26618958

  11. 4D MRI of renal function in the developing mouse

    PubMed Central

    Xie, Luke; Subashi, Ergys; Qi, Yi; Knepper, Mark A.; Johnson, G. Allan

    2014-01-01

    The major roles of filtration, metabolism, and high blood flow make the kidney highly vulnerable to drug-induced toxicity and other renal injuries. A method to follow kidney function is essential for early screening of toxicity and malformations. In this study, we acquired high spatiotemporal resolution (4D) datasets of normal mice to follow changes in kidney structure and function during development. The data were acquired with dynamic contrast-enhanced MRI (via keyhole imaging) and a cryogenic surface coil, allowing us to obtain a full 3D image (125-micron isotropic resolution) every 7.7 seconds over a 50-minute scan. This time course permitted demonstration of both contrast enhancement and clearance. Functional changes were measured over a 17-week course (at 3, 5, 7, 9, 13, and 17 weeks). The time dimension of the MRI dataset was processed to produce unique image contrasts for segmenting the 4 regions of the kidney: cortex (CO), outer stripe (OS) of the outer medulla (OM), inner stripe (IS) of the OM, and inner medulla (IM). Local volumes, time-to-peak (TTP) values, and decay constants (DC) were measured in each renal region. These metrics increased significantly with age, with the exception of DC values in the IS and OS. These data will serve as a foundation for studies of normal renal physiology and future studies of renal diseases that require early detection and intervention. PMID:25066408

  12. Criteria for two distinguishable fermions to form a boson

    SciTech Connect

    Ramanathan, Ravishankar; Chuan, Tan Kok; Kurzynski, Pawel; Santos, Marcelo F.; Kaszlikowski, Dagomir

    2011-09-15

    We study the necessary conditions for systems composed of two distinguishable fermions to exhibit bosonic behavior. We base our analysis on tools of quantum information theory such as entanglement, local operations and classical communication and the majorization criterion for probability distributions. Introduction of these tools yields new insights into the old and important problem of identifying the conditions for existence of composite bosons. We precisely identify the role entanglement plays in the formation and behavior of such composite particles.

  13. Distinguishing Indirect Signatures Arising From New Physics at the NLC

    E-print Network

    Thomas G. Rizzo

    1999-07-13

    Many sources of new physics can lead to shifts in the Standard Model predictions for cross sections and asymmetries at the NLC below their direct production thresholds. In this talk we discuss some of the tools that are useful for distinguishing amongst these new physics scenarios. R-parity violation and extensions of the Standard Model gauge structure are two typical non-minimal realizations of supersymmetry which provide us with an important test case to examine.

  14. k-Boson Quantum Walks Do Not Distinguish Arbitrary Graphs

    E-print Network

    Jamie Smith

    2010-04-01

    In this paper, we define k-equivalence, a relation on graphs that relies on their associated cellular algebras. We show that a k-Boson quantum walk cannot distinguish pairs of graphs that are k- equivalent. The existence of pairs of k-equivalent graphs has been shown by Ponomarenko et al. [2, 6]. This gives a negative answer to a question posed by Gamble et al. [7].

  15. Malignant Peripheral Nerve Sheath Tumor: MRI and CT Findings

    PubMed Central

    Kragha, K. O.

    2015-01-01

    This is a case report of a 56-year-old male with hypertension who presented with urinary retention and bowel incontinence. CT and MRI of the abdomen and pelvis showed a large complex cystic and solid enhancing mass in the right presacral space. Pathology biopsy result showed malignant peripheral nerve sheath tumor (MPNST) with extensive necrosis. The diagnosis of MPNST is extremely difficult due to the lack of (1) conclusive immunohistochemistry or unique chromosomal anomaly, (2) universal distinctive histopathology, and (3) clinical criteria. The clinical, radiologic, and histologic presentation of MPNST is important in its diagnosis. A rare case of MPNST that produced urinary retention and bowel incontinence is presented that may aid clinicians in the diagnosis of this rare clinical entity. Motor weakness, central enhancement, and immunohistochemistry may assist in the diagnosis of MPNST and differentiation between benign peripheral nerve sheath tumor (BPNST) and MPNST. PMID:26634167

  16. Can accretion disk properties distinguish gravastars from black holes?

    E-print Network

    Tiberiu Harko; Zoltán Kovács; Francisco S. N. Lobo

    2009-09-04

    Gravastars, hypothetic astrophysical objects, consisting of a dark energy condensate surrounded by a strongly correlated thin shell of anisotropic matter, have been proposed as an alternative to the standard black hole picture of general relativity. Observationally distinguishing between astrophysical black holes and gravastars is a major challenge for this latter theoretical model. In the context of stationary and axially symmetrical geometries, a possibility of distinguishing gravastars from black holes is through the comparative study of thin accretion disks around rotating gravastars and Kerr-type black holes, respectively. In the present paper, we consider accretion disks around slowly rotating gravastars, with all the metric tensor components estimated up to the second order in the angular velocity. Due to the differences in the exterior geometry, the thermodynamic and electromagnetic properties of the disks (energy flux, temperature distribution and equilibrium radiation spectrum) are different for these two classes of compact objects, consequently giving clear observational signatures. In addition to this, it is also shown that the conversion efficiency of the accreting mass into radiation is always smaller than the conversion efficiency for black holes, i.e., gravastars provide a less efficient mechanism for converting mass to radiation than black holes. Thus, these observational signatures provide the possibility of clearly distinguishing rotating gravastars from Kerr-type black holes.

  17. Reversible or not? Distinguishing agglomeration and aggregation at the nanoscale.

    PubMed

    Sokolov, Stanislav V; Tschulik, Kristina; Batchelor-McAuley, Christopher; Jurkschat, Kerstin; Compton, Richard G

    2015-10-01

    Nanoparticles are prone to clustering either via aggregation (irreversible) or agglomeration (reversible) processes. It is exceedingly difficult to distinguish the two via conventional techniques such as dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), or electron microscopy imaging (scanning electron microscopy (SEM), transmission electron microscopy (TEM)) as such techniques only generally confirm the presence of large particle clusters. Herein we develop a joint approach to tackle the issue of distinguishing between nanoparticle aggregation vs agglomeration by characterizing a colloidal system of Ag NPs using DLS, NTA, SEM imaging and the electrochemical nanoimpacts technique. In contrast to the conventional techniques which all reveal the presence of large clusters of particles, electrochemical nanoimpacts provide information regarding individual nanoparticles in the solution phase and reveal the presence of small nanoparticles (<30 nm) even in high ionic strength (above 0.5 M KCl) and allow a more complete analysis. The detection of small nanoparticles in high ionic strength media evidence the clustering to be a reversible process. As a result it is concluded that agglomeration rather than irreversible aggregation takes place. This observation is of general importance for all colloids as it provides a feasible analysis technique for a wide range of systems with an ability to distinguish subtly different processes. PMID:26352558

  18. Complementarity and path distinguishability: Some recent results concerning photon pairs

    NASA Technical Reports Server (NTRS)

    Shimony, Abner; Jaeger, Gregg

    1994-01-01

    Two results concerning photon pairs, one previously reported and one new, are summarized. It was previously shown that if the two photons are prepared in a quantum state formed from bar-A and bar-A' for photon 1 and bar-B and bar-B' for photon 2, then both one- and two-particle interferometry can be studied. If upsilon(sub i) is the visibility of one-photon interference fringes (i = 1,2) and upsilon(sub 12) is the visibility of two-photon fringes (a concept which we explicitly define), then upsilon(sub i) squared + upsilon(sub 12) squared is less than or equal to 1. The second result concerns the distinguishability of the paths of photon 2, using the known 2-photon state. A proposed measure E for path distinguishability is based upon finding an optimum strategy for betting on the outcome of a path measurement. Mandel has also proposed a measure of distinguishability P(sub D), defined in terms of the density operator rho of photon 2. We show that E is greater than or equal to P(sub D) and that upsilon(sub 2) = (1 - E(exp 2))exp 1/2.

  19. MRI

    MedlinePLUS

    ... sweatpants and a t-shirt). Certain types of metal can cause blurry images. You will lie on ... placed artificial joints Vascular stents Worked with sheet metal in the past (you may need tests to ...

  20. Portable MRI developed at Los Alamos

    SciTech Connect

    Espy, Michelle

    2015-04-22

    Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are so sensitive they'll respond to a truck driving by outside or a radio signal 50 miles away," said Al Urbaitis, a bMRI engineer. The team's first generation bMRI had to be built in a large metal housing in order to shield it from interference. Now the Los Alamos team is working in the open environment without the large metal housing using a lightweight series of wire coils that surround the bMRI system to compensate the Earth’s magnetic field. In the future, the field compensation system will also function similar to noise-cancelling headphones to eradicate invading magnetic field signals on-the-fly.