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Sample records for row ct comparison

  1. 320-Row wide volume CT significantly reduces density heterogeneity observed in the descending aorta: comparisons with 64-row helical CT.

    PubMed

    Yamashiro, Tsuneo; Miyara, Tetsuhiro; Honda, Osamu; Kamiya, Ayano; Tanaka, Yuko; Murayama, Sadayuki

    2014-01-01

    The aim of this study was to compare density heterogeneity on wide volume (WV) scans with that on helical CT scans. 22 subjects underwent chest CT using 320-WV and 64-helical modes. Density heterogeneity of the descending aorta was evaluated quantitatively and qualitatively. At qualitative assessment, the heterogeneity was judged to be smaller on WV scans than on helical scans (p<0.0001). Mean changes in aortic density between two contiguous slices were 1.64 HU (3.40%) on WV scans and 2.29 HU (5.19%) on helical scans (p<0.0001). CT density of thoracic organs is more homogeneous and reliable on WV scans than on helical scans. PMID:24210879

  2. Physical evaluation of CT scan methods for radiation therapy planning: comparison of fast, slow and gating scan using the 256-detector row CT scanner

    NASA Astrophysics Data System (ADS)

    Mori, Shinichiro; Kanematsu, Nobuyuki; Mizuno, Hideyuki; Sunaoka, Masayoshi; Endo, Masahiro

    2006-02-01

    Although slow-rotation CT scanning (slow-scan CT: SSCT) has been used for radiation therapy planning, based on the rationale that the average duration of the human respiratory cycle is 4 s, a number of physical and quantitative questions require answering before it can be adopted for clinical use. This study was performed to evaluate SSCT physically in comparison with other scan methods, including respiratory-gated CT (RGCT), and to develop procedures to improve treatment accuracy. Evaluation items were geometrical accuracy, volume accuracy, water equivalent length and dose distribution using the 256-detector row CT with three scan methods. Fast-scan CT (FSCT) was defined as obtaining all respiratory phases in cine scan mode at 1.0 s per rotation. FSCT-ave was the averaged FSCT images in all respiratory phases, obtained by reconstructing short time intervals. SSCT has been defined as scanning with slow gantry rotation to capture the whole respiratory cycle in one rotation. RGCT was scanned at the most stable point in the respiratory cycle, which provides the same image as that by FSCT at the most stable point. Results showed that all evaluation items were dependent on motion characteristics. The findings of this study indicate that 3D planning based solely on SSCT under free breathing may result in underdosing of the target volume and increase toxicity to surrounding normal tissues. Of the three methods, RGCT showed the best ability to significantly increase the accuracy of dose distribution, and provided more information to minimize the margins. FSCT-ave is a satisfactory radiotherapy planning alternative if RGCT is not available.

  3. Diagnosis of Small-Bowel Diseases: Prospective Comparison of Multi-Detector Row CT Enterography with MR Enterography.

    PubMed

    Masselli, Gabriele; Di Tola, Marco; Casciani, Emanuele; Polettini, Elisabetta; Laghi, Francesca; Monti, Riccardo; Bernieri, Maria Giulia; Gualdi, Gianfranco

    2016-05-01

    Purpose To prospectively compare the accuracies of computed tomographic (CT) enterography and magnetic resonance (MR) enterography for the detection and characterization of small-bowel diseases. Materials and Methods The institutional review board approved the study protocol, and informed consent was obtained from all participants. From June 2009 to July 2013, 150 consecutive patients (81 men and 69 women; mean age, 38.8 years; range, 18-74 years), who were suspected of having a small-bowel disease on the basis of clinical findings and whose previous upper and lower gastrointestinal endoscopy findings were normal, underwent CT and MR enterography. Two independent readers reviewed CT and MR enterographic images for the presence of small-bowel diseases, for differentiating between inflammatory and noninflammatory diseases, and for extraenteric complications. The histopathologic findings of surgical (n = 23) and endoscopic (n = 32) biopsy specimens were used as the reference standard; the results of video-capsule endoscopy (n = 36) and clinical follow-up (n = 59) were used only to confirm the absence of small-bowel disease. Results MR and CT enterography were successfully performed in all 150 patients. Overall sensitivity, specificity, and accuracy, respectively, in identifying patients with small-bowel lesions were 75.9% (41 of 54), 94.8% (91 of 96), and 88.0% (132 of 150) for CT enterography and 92.6% (50 of 54), 99.0% (95 of 96), and 96.7% (145 of 150) for MR enterography. The sensitivity of MR enterography was significantly higher than that of CT enterography for the detection of both overall small-bowel diseases (P = .0159) and neoplastic diseases (P = .0412) but not for the detection of inflammatory diseases (P > .99) or noninflammatory and nonneoplastic diseases (P = .6171). Conclusion MR enterography is more accurate than CT enterography in the detection of small-bowel diseases; MR enterography was more accurate in detecting neoplastic diseases in particular

  4. CT Coronary Angiography: 256-Slice and 320-Detector Row Scanners

    PubMed Central

    Hsiao, Edward M.; Rybicki, Frank J.; Steigner, Michael

    2010-01-01

    Multidetector computed tomography (MDCT) has rapidly evolved from 4-detector row systems in 1998 to 256-slice and 320-detector row CT systems. With smaller detector element size and faster gantry rotation speed, spatial and temporal resolution of the 64-detector MDCT scanners have made coronary artery imaging a reliable clinical test. Wide-area coverage MDCT, such as the 256-slice and 320-detector row MDCT scanners, has enabled volumetric imaging of the entire heart free of stair-step artifacts at a single time point within one cardiac cycle. It is hoped that these improvements will be realized with greater diagnostic accuracy of CT coronary angiography. Such scanners hold promise in performing a rapid high quality “triple rule-out” test without high contrast load, improved myocardial perfusion imaging, and even four-dimensional CT subtraction angiography. These emerging technical advances and novel applications will continue to change the way we study coronary artery disease beyond detecting luminal stenosis. PMID:20425186

  5. Multi-detector row CT of pancreatic islet cell tumors.

    PubMed

    Horton, Karen M; Hruban, Ralph H; Yeo, Charles; Fishman, Elliot K

    2006-01-01

    Pancreatic islet cell tumors (ICTs) are neuroendocrine neoplasms that produce and secrete hormones to a variable degree. These neoplasms can present a diagnostic challenge, both clinically and radiologically. ICTs can be classified as either syndromic or nonsyndromic on the basis of their clinical manifestations. Multi-detector row computed tomography (CT) plays an important role in the diagnosis and staging of both syndromic and nonsyndromic ICTs. In general, syndromic ICTs are less than 3 cm in size. They are typically hyperenhancing and are usually best seen on CT scans obtained during the arterial phase. Nonsyndromic ICTs tend to be larger than syndromic ICTs at presentation and are more likely to be cystic or necrotic. It is important for the radiologist to be familiar with appropriate CT protocol for the evaluation of patients with suspected pancreatic ICT and to understand the variable CT appearances of these neoplasms. PMID:16549609

  6. 64 Slice multi-detector row cardiac CT.

    PubMed

    Pannu, Harpreet K; Johnson, Pamela T; Fishman, Elliot K

    2009-01-01

    Cardiac imaging is feasible with multi-detector row (MDCT) scanners. Coronary arterial anatomy and both non-calcified and calcified plaques are depicted at CT coronary angiography. Vessel wall pathology and luminal diameter are depicted, and secondary myocardial changes may also be seen. Diagnostic capacity has increased with technological advancement, and preliminary investigations confirm the utility of 64-MDCT in low- and intermediate-risk patients who present to the emergency department with acute chest pain. The clinical indications, 64-MDCT technique, and MDCT findings in coronary artery disease are reviewed. PMID:18941811

  7. Multiplanar and three-dimensional multi-detector row CT of thoracic vessels and airways in the pediatric population.

    PubMed

    Siegel, Marilyn J

    2003-12-01

    Multi-detector row computed tomography (CT) has changed the approach to imaging of thoracic anatomy and disease in the pediatric population. At the author's institution, multi-detector row CT with multiplanar and three-dimensional reconstruction has become an important examination in the evaluation of systemic and pulmonary vasculature and the tracheobronchial tree. In some clinical situations, multi-detector row CT with reformatted images is obviating conventional angiography, which is associated with higher radiation doses and longer sedation times. Although multi-detector row CT with multiplanar and three-dimensional reconstruction is expanding the applications of CT of the thorax, its role as a diagnostic tool still needs to be better defined. The purposes of this article are to describe how to perform multi-detector row CT with multiplanar and three-dimensional reconstruction in young patients, to discuss various reconstruction techniques available, and to discuss applications in the evaluation of vascular and airways diseases. PMID:14563904

  8. Uncommon Complex Anomaly of Inferior Vena Cava and Left Iliac Vein Demonstrated by Multidetector-Row CT Angiography

    PubMed Central

    Ogul, Hayri; Yuce, Ihsan; Yalcin, Ahmet; Karaca, Leyla; Okur, Aylin; Kantarci, Mecit

    2014-01-01

    Retroperitoneal venous anomalies have clinical importance in retroperitoneal and pelvic surgery. Multidetector-row computed tomography (CT) angiography is an important imaging method to be preferred in evaluating vascular structures in this locality. We describe a complex retroperitoneal venous anomaly with a multidetector-row CT angiography. PMID:25437601

  9. Comparison of Single Row, Twin Row, and Diamond Planting Patterns in Valencia Peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most Valencia peanuts are grown in single rows on 36 to 40 inch beds. Because of their bunch-type and erect growth habit, Valencia peanuts do not spread over the whole bed and have the opportunity to benefit from multiple row planting arrangements. This study was conducted at locations near Portal...

  10. Comparisons of single-row and twin-row soybean production in the Mid South

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A Maturity Group (MG) IV and MG V soybean [Glycine max (L.) Merr] cultivar were planted in single-rows and twin-rows on 102 cm beds at 20, 30, 40, and 50 seeds m-2 in a Beulah fine sandy loam (coarse-loamy, mixed thermic Typic Dystrochrepts) in 2008, 2009, 2010 and Sharkey clay (Vertic Haplaquept) i...

  11. Image quality and radiation reduction of 320-row area detector CT coronary angiography with optimal tube voltage selection and an automatic exposure control system: comparison with body mass index-adapted protocol.

    PubMed

    Lim, Jiyeon; Park, Eun-Ah; Lee, Whal; Shim, Hackjoon; Chung, Jin Wook

    2015-06-01

    To assess the image quality and radiation exposure of 320-row area detector computed tomography (320-ADCT) coronary angiography with optimal tube voltage selection with the guidance of an automatic exposure control system in comparison with a body mass index (BMI)-adapted protocol. Twenty-two patients (study group) underwent 320-ADCT coronary angiography using an automatic exposure control system with the target standard deviation value of 33 as the image quality index and the lowest possible tube voltage. For comparison, a sex- and BMI-matched group (control group, n = 22) using a BMI-adapted protocol was established. Images of both groups were reconstructed by an iterative reconstruction algorithm. For objective evaluation of the image quality, image noise, vessel density, signal to noise ratio (SNR), and contrast to noise ratio (CNR) were measured. Two blinded readers then subjectively graded the image quality using a four-point scale (1: nondiagnostic to 4: excellent). Radiation exposure was also measured. Although the study group tended to show higher image noise (14.1 ± 3.6 vs. 9.3 ± 2.2 HU, P = 0.111) and higher vessel density (665.5 ± 161 vs. 498 ± 143 HU, P = 0.430) than the control group, the differences were not significant. There was no significant difference between the two groups for SNR (52.5 ± 19.2 vs. 60.6 ± 21.8, P = 0.729), CNR (57.0 ± 19.8 vs. 67.8 ± 23.3, P = 0.531), or subjective image quality scores (3.47 ± 0.55 vs. 3.59 ± 0.56, P = 0.960). However, radiation exposure was significantly reduced by 42 % in the study group (1.9 ± 0.8 vs. 3.6 ± 0.4 mSv, P = 0.003). Optimal tube voltage selection with the guidance of an automatic exposure control system in 320-ADCT coronary angiography allows substantial radiation reduction without significant impairment of image quality, compared to the results obtained using a BMI-based protocol. PMID:25604967

  12. [Multidetector row CT in assessment of coronary artery calcification on hemodialisis].

    PubMed

    Caro, P; Delgado, R; Dapena, F; Núñez, A

    2007-01-01

    Vascular calcification is a strong predictor of cardiovascular and all-cause mortality. Coronary artery calcification is more frequent, more extensive and progresses more rapidly in CKD than in general population. They are also considered a marker of coronary heart disease, with high prevalence and functional significance. It suggests that detection and surveillance may be worthwhile in general clinical practice. New non-invasive image techniques, like Multi-detector row CT, a type of spiral scanner, assess density and volume of calcification at multiple sites and allow quantitative scoring of vascular calcification using calcium scores analogous to those from electron-beam CT. We have assessed and quantified coronary artery calcification with 16 multidetector row CT in 44 patients on hemodialysis and their relationship with several cardiovascular risk factors. Coronary artery calcification prevalence was of 84 % with mean calcium score of 1580 +/- 2010 ( r 0-9844) with calcium score > 400 in 66% of patients. It was usually multiple, affecting more than two vessels in more than 50%. In all but one patient, left anterior descending artery was involved with higher calcium score level at right coronary artery. Advanced age, male, diabetes, smoking, more morbidity, cerebrovascular disease previous, and calcium-binders phosphate and analogous vitamin D treatment would seem to be associated with coronary artery calcification. Coronary artery calcification is very frequent and extensive, usually multiple and associated to modifiable risk factors in hemodialysis patients. Multi-detector-row CT seems an effective, suitable, readily applicable method to assess and quantify coronary artery calcification. PMID:18336102

  13. Comparison of Exercise Performance on Rowing and Cycle Ergometers.

    ERIC Educational Resources Information Center

    Mahler, Donald A.; And Others

    1987-01-01

    The purpose of this study was to compare exercise performance and cardiorespiratory responses on the rowing ergometer with those on the cycle ergometer. Findings are presented and explained. (Author/MT)

  14. Evaluation of different small bowel contrast agents by multi - detector row CT

    PubMed Central

    Wang, Yong-Ren; Yu, Xiao-Li; Peng, Zhi-Yi

    2015-01-01

    Objective: This study aims to evaluate the effects of different oral small bowel contrast agents towards the intestinal dilatation and intestinal wall structure exhibition by the abdominal multi - detector row CT (MDCT) examination. Methods: 80 patients were performed the whole abdominal CT examination, then randomly divided into four groups, with 20 patients in each group. 45 minutes before the CT examination, the patients were served with a total of 1800 ml pure water, pure milk, dilute lactulose solution and isotonic mannitol solution, respectively. Results: The images were blinded read by two experienced abdominal radiologists in the workstation, the cross-sectional diameters of duodenum, jejunum, proximal and terminal ends of ileum of each patient were measured, then the analysis of variance was performed to analyze the differences in the intestinal dilatation among the experimental groups. The scoring method was used to score the intestinal dilatation and intestinal structure exhibition. The diluted lactulose solution and 2.5% mannitol exhibited the best intestinal dilation degrees. Similarly, the diluted lactulose solution and 2.5% mannitol exhibited the highest scores in the entire small bowel dilatation degree and intestinal structure exhibition. Conclusions: 2.5% osmotic mannitol and the diluted lactulose solution enabled the full dilatation of small bowel, and could clearly exhibit the wall structure. PMID:26629131

  15. Quantitative Features of Liver Lesions, Lung Nodules, and Renal Stones at Multi-Detector Row CT Examinations: Dependency on Radiation Dose and Reconstruction Algorithm.

    PubMed

    Solomon, Justin; Mileto, Achille; Nelson, Rendon C; Roy Choudhury, Kingshuk; Samei, Ehsan

    2016-04-01

    Purpose To determine if radiation dose and reconstruction algorithm affect the computer-based extraction and analysis of quantitative imaging features in lung nodules, liver lesions, and renal stones at multi-detector row computed tomography (CT). Materials and Methods Retrospective analysis of data from a prospective, multicenter, HIPAA-compliant, institutional review board-approved clinical trial was performed by extracting 23 quantitative imaging features (size, shape, attenuation, edge sharpness, pixel value distribution, and texture) of lesions on multi-detector row CT images of 20 adult patients (14 men, six women; mean age, 63 years; range, 38-72 years) referred for known or suspected focal liver lesions, lung nodules, or kidney stones. Data were acquired between September 2011 and April 2012. All multi-detector row CT scans were performed at two different radiation dose levels; images were reconstructed with filtered back projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction (MBIR) algorithms. A linear mixed-effects model was used to assess the effect of radiation dose and reconstruction algorithm on extracted features. Results Among the 23 imaging features assessed, radiation dose had a significant effect on five, three, and four of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). Adaptive statistical iterative reconstruction had a significant effect on three, one, and one of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). MBIR reconstruction had a significant effect on nine, 11, and 15 of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). Of note, the measured size of lung nodules and renal stones with MBIR was significantly different than those for the other two algorithms (P < .002 for all comparisons). Although lesion texture was

  16. Novel ultrahigh resolution data acquisition and image reconstruction for multi-detector row CT

    SciTech Connect

    Flohr, T. G.; Stierstorfer, K.; Suess, C.; Schmidt, B.; Primak, A. N.; McCollough, C. H.

    2007-05-15

    We present and evaluate a special ultrahigh resolution mode providing considerably enhanced spatial resolution both in the scan plane and in the z-axis direction for a routine medical multi-detector row computed tomography (CT) system. Data acquisition is performed by using a flying focal spot both in the scan plane and in the z-axis direction in combination with tantalum grids that are inserted in front of the multi-row detector to reduce the aperture of the detector elements both in-plane and in the z-axis direction. The dose utilization of the system for standard applications is not affected, since the grids are moved into place only when needed and are removed for standard scanning. By means of this technique, image slices with a nominal section width of 0.4 mm (measured full width at half maximum=0.45 mm) can be reconstructed in spiral mode on a CT system with a detector configuration of 32x0.6 mm. The measured 2% value of the in-plane modulation transfer function (MTF) is 20.4 lp/cm, the measured 2% value of the longitudinal (z axis) MTF is 21.5 lp/cm. In a resolution phantom with metal line pair test patterns, spatial resolution of 20 lp/cm can be demonstrated both in the scan plane and along the z axis. This corresponds to an object size of 0.25 mm that can be resolved. The new mode is intended for ultrahigh resolution bone imaging, in particular for wrists, joints, and inner ear studies, where a higher level of image noise due to the reduced aperture is an acceptable trade-off for the clinical benefit brought about by the improved spatial resolution.

  17. Overbeaming and overlapping of volume-scan CT with tube current modulation in a 320-detector row CT scanner

    NASA Astrophysics Data System (ADS)

    Liao, Ying-Lan; Chen, Yan-Shi; Lai, Nan-Ku; Chuang, Keh-Shih; Tsai, Hui-Yu

    2014-11-01

    The purpose of this study was to evaluate the performance of volume scan tube current modulation (VS-ATCM) with adaptive iterative dose reduction 3D (AIDR3D) technique in abdomen CT examinations. We scanned an elliptical cone-shaped phantom utilizing AIDR3D technique combined with VS-ATCM mode in a 320-detector row CT scanner. The image noise distributions with conventional filtered back-projction (FBP) technique and those with AIDR3D technique were compared. The radiation dose profile and tube current time product (mAs) in three noise levels of VS-ATCM modes were compared. The radiation beam profiles of five preset scan lengths were measured using Gafchromic film strips to assess the effects of overbeaming and everlapping. The results indicated that the image noises with AIDR3D technique was 13-74% lower than those in FBP technique. The mAs distributions can be a prediction for various abdominal sizes when undergoing a VS-ATCM mode scan. Patients can receive the radiation dose of overbeaming and overlapping during the VS-ATCM mode scans.

  18. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    PubMed

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required. PMID:16211320

  19. Radiation Dose from Single-Heartbeat Coronary CT Angiography Performed with a 320–Detector Row Volume Scanner1

    PubMed Central

    Elliston, Carl D.; Arai, Andrew E.; Chen, Marcus Y.; Mather, Richard; Pearson, Gregory D. N.; DeLaPaz, Robert L.; Nickoloff, Edward; Dutta, Ajoy; Brenner, David J.

    2010-01-01

    Purpose: To determine radiation doses from coronary computed tomographic (CT) angiography performed by using a 320–detector row volume scanner and evaluate how the effective dose depends on scan mode and the calculation method used. Materials and Methods: Radiation doses from coronary CT angiography performed by using a volume scanner were determined by using metal-oxide–semiconductor field-effect transistor detectors positioned in an anthropomorphic phantom physically and radiographically simulating a male or female human. Organ and effective doses were determined for six scan modes, including both 64-row helical and 280-row volume scans. Effective doses were compared with estimates based on the method most commonly used in clinical literature: multiplying dose-length product (DLP) by a general conversion coefficient (0.017 or 0.014 mSv·mGy−1·cm−1), determined from Monte Carlo simulations of chest CT by using single-section scanners and previous tissue-weighting factors. Results: Effective dose was reduced by up to 91% with volume scanning relative to helical scanning, with similar image noise. Effective dose, determined by using International Commission on Radiological Protection publication 103 tissue-weighting factors, was 8.2 mSv, using volume scanning with exposure permitting a wide reconstruction window, 5.8 mSv with optimized exposure and 4.4 mSv for optimized 100-kVp scanning. Estimating effective dose with a chest conversion coefficient resulted in a dose as low as 1.8 mSv, substantially underestimating effective dose for both volume and helical coronary CT angiography. Conclusion: Volume scanning markedly decreases coronary CT angiography radiation doses compared with those at helical scanning. When conversion coefficients are used to estimate effective dose from DLP, they should be appropriate for the scanner and scan mode used and reflect current tissue-weighting factors. © RSNA, 2010 PMID:20177085

  20. Missed rib fractures on evaluation of initial chest CT for trauma patients: pattern analysis and diagnostic value of coronal multiplanar reconstruction images with multidetector row CT

    PubMed Central

    Cho, S H; Sung, Y M; Kim, M S

    2012-01-01

    Objective The objective of this study was to review the prevalence and radiological features of rib fractures missed on initial chest CT evaluation, and to examine the diagnostic value of additional coronal images in a large series of trauma patients. Methods 130 patients who presented to an emergency room for blunt chest trauma underwent multidetector row CT of the thorax within the first hour during their stay, and had follow-up CT or bone scans as diagnostic gold standards. Images were evaluated on two separate occasions: once with axial images and once with both axial and coronal images. The detection rates of missed rib fractures were compared between readings using a non-parametric method of clustered data. In the cases of missed rib fractures, the shapes, locations and associated fractures were evaluated. Results 58 rib fractures were missed with axial images only and 52 were missed with both axial and coronal images (p=0.088). The most common shape of missed rib fractures was buckled (56.9%), and the anterior arc (55.2%) was most commonly involved. 21 (36.2%) missed rib fractures had combined fractures on the same ribs, and 38 (65.5%) were accompanied by fracture on neighbouring ribs. Conclusion Missed rib fractures are not uncommon, and radiologists should be familiar with buckle fractures, which are frequently missed. Additional coronal imagescan be helpful in the diagnosis of rib fractures that are not seen on axial images. PMID:22514102

  1. Misty mesentery: a pictorial review of multidetector-row CT findings.

    PubMed

    Filippone, A; Cianci, R; Di Fabio, F; Storto, M L

    2011-04-01

    The term "misty mesentery" indicates a pathological increase in mesenteric fat attenuation at computed tomography (CT). It is frequently observed on multidetector CT (MDCT) scans performed during daily clinical practice and may be caused by various pathological conditions, including oedema, inflammation, haemorrhage, neoplastic infiltration or sclerosing mesenteritis. In patients suffering from acute abdominal disease, misty mesentery may be considered a feature of the underlying disease. Otherwise, it may represent an incidental finding on MDCT performed for other reasons. This article describes the MDCT features of misty mesentery in different diseases in order to provide a rational approach to the differential diagnosis. PMID:21311992

  2. Comparison of the Diagnostic Image Quality of the Canine Maxillary Dentoalveolar Structures Obtained by Cone Beam Computed Tomography and 64-Multidetector Row Computed Tomography.

    PubMed

    Soukup, Jason W; Drees, Randi; Koenig, Lisa J; Snyder, Christopher J; Hetzel, Scott; Miles, Chanda R; Schwarz, Tobias

    2015-01-01

    The objective of this blinded study was to validate the use of cone beam computed tomography (C) for imaging of the canine maxillary dentoalveolar structures by comparing its diagnostic image quality with that of 64-multidetector row CT Sagittal slices of a tooth-bearing segment of the maxilla of a commercially purchased dog skull embedded in methylmethacrylate were obtained along a line parallel with the dental arch using a commercial histology diamond saw. The slice of tooth-bearing bone that best depicted the dentoalveolar structures was chosen and photographed. The maxillary segment was imaged with cone beam CT and 64-multidetector row CT. Four blinded evaluators compared the cone beam CT and 64-multidetector row CT images and image quality was scored as it related to the anatomy of dentoalveolar structures. Trabecular bone, enamel, dentin, pulp cavity, periodontal ligament space, and lamina dura were scored In addition, a score depicting the evaluators overall impression of the image was recorded. Images acquired with cone beam CT were found to be significantly superior in image quality to images acquired with 64-multidetector row CT overall, and in all scored categories. In our study setting cone beam CT was found to be a valid and clinically superior imaging modality for the canine maxillary dentoalveolar structures when compared to 64-multidetector row CT. PMID:26415384

  3. Diagnostic Performance of Transluminal Attenuation Gradient and Noninvasive Fractional Flow Reserve Derived from 320-Detector Row CT Angiography to Diagnose Hemodynamically Significant Coronary Stenosis: An NXT Substudy.

    PubMed

    Ko, Brian S; Wong, Dennis T L; Nørgaard, Bjarne L; Leong, Darryl P; Cameron, James D; Gaur, Sara; Marwan, Mohamed; Achenbach, Stephan; Kuribayashi, Sachio; Kimura, Takeshi; Meredith, Ian T; Seneviratne, Sujith K

    2016-04-01

    Purpose To compare the diagnostic performance of 320-detector row computed tomography (CT) coronary angiography-derived computed fractional flow reserve (FFR; FFRCT), transluminal attenuation gradient (TAG; TAG320), and CT coronary angiography alone to diagnose hemodynamically significant stenosis as determined by invasive FFR. Materials and Methods This substudy of the prospective NXT study (no. NCT01757678) was approved by each participating institution's review board, and informed consent was obtained from all participants. Fifty-one consecutive patients who underwent 320-detector row CT coronary angiographic examination and invasive coronary angiography with FFR measurement were included. Independent core laboratories determined coronary artery disease severity by using CT coronary angiography, TAG320, FFRCT, and FFR. TAG320 is defined as the linear regression coefficient between luminal attenuation and axial distance from the coronary ostium. FFRCT was computed from CT coronary angiography data by using computational fluid dynamics technology. Diagnostic performance was evaluated and compared on a per-vessel basis by the area under the receiver operating characteristic (ROC) curve (AUC). Results Among 82 vessels, 24 lesions (29%) had ischemia by FFR (FFR ≤ 0.80). FFRCT exhibited a stronger correlation with invasive FFR compared with TAG320 (Spearman ρ, 0.78 vs 0.47, respectively). Overall per-vessel accuracy, sensitivity, specificity, and positive and negative predictive values for TAG320 (<15.37) were 78%, 58%, 86%, 64%, and 83%, respectively; and those of FFRCT were 83%, 92%, 79%, 65%, and 96%, respectively. ROC curve analysis showed a significantly larger AUC for FFRCT (0.93) compared with that for TAG320 (0.72; P = .003) and CT coronary angiography alone (0.68; P = .008). Conclusion FFRCT computed from 320-detector row CT coronary angiography provides better diagnostic performance for the diagnosis of hemodynamically significant coronary stenoses

  4. Detection, visualization and evaluation of anomalous coronary anatomy on 16-slice multidetector-row CT.

    PubMed

    van Ooijen, Peter M A; Dorgelo, Joost; Zijlstra, Felix; Oudkerk, Matthijs

    2004-12-01

    Early identification and evaluation of relatively frequent anomalous coronary anatomy is quite relevant because of the occurrence of sudden cardiac death or related symptoms of myocardial ischemia. Selective coronary angiography (CAG) is invasive, expensive and cannot always provide the required information adequately. Recently, non-invasive imaging techniques such as magnetic resonance imaging and multidetector-row computed tomography (MDCT) have been shown to provide a good anatomical view of the coronary artery tree. This study aims to demonstrate the value of 16-MDCT for evaluation of anomalous coronary anatomy. In 13 patients scanned using 16-MDCT, six different coronary anomalies were diagnosed [two absent left main, one single vessel left coronary artery (LCA), three LCA originating from the right (two with interarterial course), six right coronary artery originating from the left, one double left anterior descending (LAD)]. Mean diagnostic quality, recorded by two observers using a 5-point scale (1= non-diagnostic to 5= excellent diagnostic quality), resulted in a mean score of 3.73 (SD 1.19) without any non-diagnostic result. MDCT offers an accurate diagnostic modality to visualize the origin and course of anomalous coronary arteries by a three-dimensional display of anatomy. Shortcomings in CAG can be overcome by the use of contrast-enhanced MDCT. PMID:15452665

  5. Weed Control and Yield Comparisons of Twin- and Single-row Glyphosate Resistant Cotton Production Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 2-yr field study was conducted during 2007 and 2008 at Stoneville, MS, to determine the effect of twin-row (two rows 38 cm apart on 102-cm beds) and single-row (on 102-cm beds) pattern and glyphosate POST applications with and without fluometuron + S-metolachlor PRE on cotton canopy closure, weed ...

  6. Optimised z-axis coverage at multidetector-row CT in adults suspected of acute appendicitis

    PubMed Central

    Brassart, N; Winant, C; Tack, D; Gevenois, P A; De Maertelaer, V

    2013-01-01

    Objective: To compare diagnostic performances of two reduced z-axis coverages to full coverage of the abdomen and pelvis for the diagnosis of acute appendicitis and alternative diseases at unenhanced CT. Methods: This study included 152 adults suspected of appendicitis who were enrolled in two ethical committee-approved previous prospective trials. Based on scans covering the entire abdomen and pelvis (set L), two additional sets of images were generated, each with reduced z-axis coverages: (1) from the top of the iliac crests to the pubis (set S) and (2) from the diaphragmatic crus to the pubis (set M). Two readers independently coded the visualisation of the appendix, measured its diameter and proposed a diagnosis (appendicitis or alternative). Final diagnosis was based on surgical findings or clinical follow-up. Fisher exact and McNemar tests and logistic regression were used. Results: 46 patients had a definite diagnosis of appendicitis and 53 of alternative diseases. The frequency of appendix visualisation was lower for set S than set L for both readers (89% and 84% vs 95% and 91% by Readers A and B, respectively; p=0.021 and 0.022). The probability of giving a correct diagnosis was lower for set S (68%) than set L (78%; odds ratio, 0.611; p=0.008) for both readers, without significant difference between sets L and M (77%, p=0.771); z-axis coverage being reduced by 25% for set M. Conclusion: Coverage from diaphragmatic crus to pubis, but not focused on pelvis only, can be recommended in adults suspected of appendicitis. Advances in knowledge: In suspected appendicitis, CT-coverage can be reduced from diaphragmatic crus to pubis. PMID:23690436

  7. Comparison of different rowing exercises: trunk muscle activation and lumbar spine motion, load, and stiffness.

    PubMed

    Fenwick, Chad M J; Brown, Stephen H M; McGill, Stuart M

    2009-08-01

    The objective of this study was to investigate 3 different rowing exercises and quantify the muscle activation of the torso and the hip musculature, together with the corresponding spinal loading and stiffness. Seven healthy male subjects from a university population were instrumented to obtain surface electromyography of selected trunk and hip muscles and to obtain spine position using an electromagnetic spine position sensor, together with video analysis to calculate joint moments. The 3 rowing exercises investigated are the inverted row, standing bent-over row, and the standing 1-armed cable row. The inverted row elicited the highest activation of the latissimus dorsi muscles, upper back, and hip extensor muscles. The lower activation of the lumbar erector spinae muscles during the inverted row corresponded to the lower-spine load measured. The standing bent-over row produced large activation symmetrically across the back but produced the largest lumbar spine load. The 1-armed cable row challenged the torsional capabilities of the trunk musculature. Some "core" exercises may be better for rehabilitation (e.g., having the training goals of modest muscle activation with low spine load), while other exercises may be better for athletic training (e.g., resulting in higher muscle activation and larger spine load). When prescribing "core" exercises, those wishing to spare the low back may choose the inverted row given the lowest spine load exercise. The standing bent-over row elicited large muscle activation symmetrically from the upper to lower back, however induced larger spine loads, but not surprisingly the highest spine stiffness. If torsional endurance or strength is the training goal, the 1-armed cable row might be considered. PMID:19620925

  8. Comparison of different rowing exercises: trunk muscle activation and lumbar spine motion, load, and stiffness.

    PubMed

    Fenwick, Chad M J; Brown, Stephen H M; McGill, Stuart M

    2009-03-01

    The objective of this study was to investigate 3 different rowing exercises and quantify the muscle activation of the torso and the hip musculature, together with the corresponding spinal loading and stiffness. Seven healthy men from a university population were instrumented to obtain surface electromyography of selected trunk and hip muscles and to obtain spine position using an electromagnetic spine position sensor, together with video analysis to calculate joint moments. The 3 rowing exercises investigated were the inverted row, standing bent-over row, and standing 1-armed cable row. The inverted row elicited the highest activation of the latissimus dorsi muscles, upper-back, and hip extensor muscles. The lower activation of the lumbar erector spinae muscles during the inverted row corresponded to the lower spine load measured. The standing bent-over row produced large activation symmetrically across the back, but it produced the largest lumbar spine load. The 1-armed cable row challenged the torsional capabilities of the trunk musculature. Some core exercises may be better for rehabilitation (e.g., having the training goals of modest muscle activation with low spine load), whereas other exercises may be better for athletic training (e.g., resulting in higher muscle activation and larger spine load). When prescribing core exercises, those wishing to spare the low back may choose the inverted row, given the lowest spine load exercise. The standing bent-over row elicited large muscle activation symmetrically from the upper to lower back; it induced larger spine loads but also, not surprisingly, the highest spine stiffness. If torsional endurance or strength is the training goal, the 1-armed cable row might be considered. PMID:19197209

  9. Feasibility of tissue characterization of coronary plaques using 320-detector row computed tomography: comparison with integrated backscatter intravascular ultrasound.

    PubMed

    Takahashi, Shigekiyo; Kawasaki, Masanori; Miyata, Shusaku; Suzuki, Keita; Yamaura, Makoto; Ido, Takahisa; Aoyama, Takuma; Fujiwara, Hisayoshi; Minatoguchi, Shinya

    2016-01-01

    Recently, a new generation of multi-detector row computed tomography (CT) with 320-detector rows (DR) has become available in the clinical settings. The purpose of the present study was to determine the cutoff values of Hounsfield unit (HU) for discrimination of plaque components by comparing HU of coronary plaques with integrated backscatter intravascular ultrasound (IB-IVUS) serving as a gold standard. Seventy-seven coronary atherosclerotic lesions in 77 patients with angina were visualized by both 320-DR CT (Aquilion One, Toshiba, Japan) and IB-IVUS at the same site. To determine the thresholds for discrimination of plaque components, we compared HU with IB values as a gold standard. Optimal thresholds were determined from receiver operating characteristic (ROC) curves analysis. The HU values of lipid pool (n = 115), fibrosis (n = 93), vessel lumen and calcification (n = 73) were 28 ± 19 HU (range -18 to 69 HU), 98 ± 31 HU (44 to 195 HU), 357 ± 65 HU (227 to 534 HU) and 998 ± 236 HU (366 to 1,489 HU), respectively. The thresholds of 56 HU, 210 HU and 490 HU were the most reliable predictors of lipid pool, fibrosis, vessel lumen and calcification, respectively. Lipid volume measured by 320-DR CT was correlated with that measured by IB-IVUS (r = 0.63, p < 0.05), whereas fibrous volume measured by 320-DR CT was not. Lipid volume measured by 320-DR CT was correlated with that measured by IB-IVUS, whereas fibrous volume was not correlated with that measured by IB-IVUS because manual exclusion of the outside of vessel hindered rigorous discrimination between fibrosis and extravascular components. PMID:25217036

  10. Patient radiation dose in prospectively gated axial CT coronary angiography and retrospectively gated helical technique with a 320-detector row CT scanner

    SciTech Connect

    Seguchi, Shigenobu; Aoyama, Takahiko; Koyama, Shuji; Fujii, Keisuke; Yamauchi-Kawaura, Chiyo

    2010-11-15

    Purpose: The aim of this study was to evaluate radiation dose to patients undergoing computed tomography coronary angiography (CTCA) for prospectively gated axial (PGA) technique and retrospectively gated helical (RGH) technique. Methods: Radiation doses were measured for a 320-detector row CT scanner (Toshiba Aquilion ONE) using small sized silicon-photodiode dosimeters, which were implanted at various tissue and organ positions within an anthropomorphic phantom for a standard Japanese adult male. Output signals from photodiode dosimeters were read out on a personal computer, from which organ and effective doses were computed according to guidelines published in the International Commission on Radiological Protection Publication 103. Results: Organs that received high doses were breast, followed by lung, esophagus, and liver. Breast doses obtained with PGA technique and a phase window width of 16% at a simulated heart rate of 60 beats per minute were 13 mGy compared to 53 mGy with RGH technique using electrocardiographically dependent dose modulation at the same phase window width as that in PGA technique. Effective doses obtained in this case were 4.7 and 20 mSv for the PGA and RGH techniques, respectively. Conversion factors of dose length product to the effective dose in PGA and RGH were 0.022 and 0.025 mSv mGy{sup -1} cm{sup -1} with a scan length of 140 mm. Conclusions: CTCA performed with PGA technique provided a substantial effective dose reduction, i.e., 70%-76%, compared to RGH technique using the dose modulation at the same phase windows as those in PGA technique. Though radiation doses in CTCA with RGH technique were the same level as, or some higher than, those in conventional coronary angiography (CCA), the use of PGA technique reduced organ and effective doses to levels less than CCA except for breast dose.

  11. Comparison of rowing on a concept 2 stationary and dynamic ergometer.

    PubMed

    Benson, Aaron; Abendroth, Julianne; King, Deborah; Swensen, Thomas

    2011-01-01

    Biomechanical and physiological responses to rowing 1000 m at a power output equivalent to a 2000 m race were compared in 34 collegiate rowers (17 women, 17 men) rowing on a stationary and dynamic Concept 2 ergometer. Stroke ratio, peak handle force, rate of force development, impulse, and respiratory exchange ratio decreased by 15.7, 14.8, 10.9, 10.2 and 1.9%, respectively, on the dynamic ergometer. In contrast, percent time to peak force and stroke rate increased by 10.5 and 12.6%, respectively, during dynamic ergometry; the changes in stroke rate and impulse were greater for men than women. Last, VO2 was 5.1% higher and efficiency 5. 3% lower on the dynamic ergometer for men. Collegiate rowers used higher stoke rates and lower peak stroke forces to achieve a similar power output while rowing at race pace on the dynamic ergometer, which may have increased the cardiopulmonary demand and possibly reduced force production in the primary movers. Differences were more pronounced in males than females; this dichotomy may be more due to dynamic ergometer familiarity than sex. Key pointsWhen rowing at a constant power output, all rowers used higher stroke rates and lower stroke forces on the Concept 2 Dynamic ergometer as compared to the Concept 2 Stationary ergometer.When rowing at a constant power output, cardiopulmonary demand was higher for all rowers, as measured by heart rate, on the Concept 2 Dynamic ergometer as compared to the Concept 2 Stationary ergometer.When rowing at a constant power output, efficiency was lower for male rowers on the Concept 2 Dynamic ergometer as compared to the Concept 2 Stationary ergometer. PMID:24149871

  12. A Comparison of Ten-Key and Top Row Numeric Entry.

    ERIC Educational Resources Information Center

    Strader, J. Kelly; Baker, Clora Mae

    A study sought to determine the change in speed and accuracy after 5 hours of practice on a standardized test for 10-key numeric entry at the community college level. Specifically it sought to determine how much speed and accuracy will increase or decrease after 5 hours of practice on a 10-key numeric entry test as compared to top-row numeric…

  13. A Physiological and Kinematic Comparison of two Different Lean Back Positions During Stationary Rowing on a Concept II Machine.

    PubMed

    Bell, Gordon; Bennett, Jack; Reynolds, William; Syrotuik, Daniel; Gervais, Pierre

    2013-01-01

    This study compared two different body positions at the finish of a stroke during stationary rowing exercise on physiological and kinematic measurements. Nine male and five female rowers volunteered for the study: mean age (± SD), body height and body mass were 27 ±9 yrs, 180.5 ±12.3 cm and 81.2 ±14.2 kg. The two body positions at the finish were controlled at an upright posture or a novel greater lean back position. All subjects completed 3 different experimental trials on a Concept IID rowing machine at 3 different exercise intensities and comparisons were made between the lean back position at the same stroke rate and the same power output as the upright trial. Power output, heart rate, oxygen uptake, energy expenditure and % efficiency were higher (p<0.05) with the greater lean back position at the same stroke rate compared to all other conditions. Range of motion at the hip, ankle, and elbow and the handle velocity and distance moved were greater (p<0.05) with the lean back position. In conclusion, a greater lean back posture at the finish during stationary rowing produces a higher power output and improved efficiency at the same stroke rate but at an elevated physiological cost compared to a more upright position. Despite the higher energy expenditure, the relative gain in power output and efficiency with no negative kinematic changes suggests that a greater lean back position at the finish will enhance performance during stationary rowing exercise. PMID:24146710

  14. Yield and Fiber Properties Associated with Narrow-Row and Twin-Row Planting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Planting crops in alternate row patterns such as skip row, twin-row, or narrow-row, in comparison to conventional row patterns, has been shown to reduce seeding rates and costs, maximize utilization of space with increased plant root spacing, improve interception of light, improve canopy closure, an...

  15. Comparison of Analytical and Experimental Effectiveness of Four-Row Plate-Fin-Tube Heat Exchangers with Water, R-22, and R-410A

    SciTech Connect

    Baxter, V.D.; Chen, T.D.; Conklin, J.C.

    1998-11-15

    The analytical solutions of heat exchanger effectiveness for four-row crcmilow, cross-countertlow and cross-paralleltlow have been derived in the recent study. The main objective of this study is to investigate the etlkct of heat exchawger tlow conllguration on thermal performance with refrigerant mixtures. Difference of heat exchanger effectiveness for all flow arrangements relative to an analytical many-row solution has been analyzed. A comparison of four-row cross cou~ltet-ilow heat exchanger effectiveness between analytical solutions and experimental data with water, R-22, and R-4 10A is presented.

  16. Rowing Injuries

    PubMed Central

    Hosea, Timothy M.; Hannafin, Jo A.

    2012-01-01

    Context: Rowing is one of the original modern Olympic sports and was one of the most popular spectator sports in the United States. Its popularity has been increasing since the enactment of Title IX. The injury patterns in this sport are unique because of the stress applied during the rowing stroke. Evidence Acquisition: This review summarizes the existing literature describing the biomechanics of the rowing stroke and rowing-related injury patterns. Data were obtained from previously published peer-reviewed literature through a search of the entire PubMed database (up to December, 2011) as well as from textbook chapters and rowing coaching manuals. Results: Rowing injuries are primarily overuse related. The knee, lumbar spine, and ribs are most commonly affected. The injury incidence is directly related to the volume of training and technique. Conclusion: Familiarity of the injury patterns and the biomechanical forces affecting the rowing athlete will aid in prompt diagnosis and appropriate management. PMID:23016093

  17. Comparison of Rowing Performance Improvements Following Various High-Intensity Interval Trainings.

    PubMed

    Akca, Firat; Aras, Dicle

    2015-08-01

    The purpose of this study was to examine the effects of high-intensity interval training (HIT) and supramaximal interval training (SMIT) on indoor rowing performance; 20 male lightweight collegiate rowers (age = 21.77 ± 2.35 years, height = 178.4 ± 6 cm, body mass = 69.6 ± 3.1 kg) participated in this study. Baseline testing involved a 2,000-m time trial and incremental exercise test to determine VO2peak, peak power output (PPO), and power at 4 mmol·L blood lactate threshold. After the baseline tests, participants were allocated to SMIT or HIT intervention groups, which they performed 8 times over a 4-week period (2 times per week, 2 days apart). The SMIT involved 10 × 30-second intervals at 150% of the PPO with 4-minute rest. The HIT involved 8 × 2.5-minute intervals at 90% of the PPO with 3-minute rest. Of note, 5.7 and 5 seconds of improvements were observed in 2,000-m performance after SMIT and HIT interventions, respectively. Of note, 2,000-m time trial performance, 2,000-m power, PPO, relative, and absolute VO2peak were significantly improved after both training interventions. However, the differences between the groups were not significant. As a result, 4 weeks of SMIT improves 2,000-m rowing ergometer performance and related physiological variables in a similar fashion with HIT in collegiate rowers. PMID:25647654

  18. Comparison of standard 4-row versus 6-row 3-D linear cutter stapler in creation of gastrointestinal system anastomoses: a prospective randomized trial

    PubMed Central

    Sozutek, Alper; Colak, Tahsin; Dag, Ahmet; Olmez, Tolga

    2012-01-01

    OBJECTIVE: This prospective study was conducted to compare the clinical outcomes of a 6-row 3-D linear cutter with the standard 4-row linear cutter in patients who underwent elective gastrointestinal surgery anastomosis. METHOD: Patients who underwent elective open gastrointestinal surgery that included stapled anastomosis using a linear cutter (Proximate®, Ethicon Endo-Surgery, Cincinnati, OH) between January 2011 and May 2011 were included in the study. The patients were randomly assigned to two groups according to the linear cutter that was used in the surgery: the standard 4-row cutter (the S group) or the new 6-row cutter (the N group). The groups were compared based on the patient demographic data, the laboratory parameters, the preoperative diagnosis, the surgery performed, the operation time, intra- or postoperative complications, the time to oral tolerance and the length of the hospital stay. RESULTS: The S group included 11 male and nine female patients with a mean age of 65±12 (35-84) years, while the N group included 13 male and eight female patients with a mean age of 62±11 (46-79) years (p = 0.448, p = 0.443, respectively). Anastomotic line bleeding was observed in eight (40%) patients in the S group and in one (4.7%) patient in the N group (p = 0.006). Dehiscence of the anastomosis line was observed in two (10%) patients in the S group and none in the N group (p = 0.131). Anastomotic leakage developed in three (15%) patients in the S group and in one (4.7%) patient in the N group (p = 0.269). The mean hospital stay was 12.65±6.1 days in the S group and 9.52±2.9 days in the N group (p = 0.043). CONCLUSION: The 6-row 3-D linear cutter is a safe and easily applied instrument that can be used to create anastomoses in gastrointestinal surgery. The new stapler provides some usage benefits and is also superior to the standard linear cutter with regard to anastomotic line bleeding. PMID:23018300

  19. Rowing Physiology.

    ERIC Educational Resources Information Center

    Spinks, W. L.

    This review of the literature discusses and examines the methods used in physiological assessment of rowers, results of such assessments, and future directions emanating from research in the physiology of rowing. The first section discusses the energy demands of rowing, including the contribution of the energy system, anaerobic metabolism, and the…

  20. Rowing injuries.

    PubMed

    Rumball, Jane S; Lebrun, Constance M; Di Ciacca, Stephen R; Orlando, Karen

    2005-01-01

    Participation in the sport of rowing has been steadily increasing in recent decades, yet few studies address the specific injuries incurred. This article reviews the most common injuries described in the literature, including musculoskeletal problems in the lower back, ribs, shoulder, wrist and knee. A review of basic rowing physiology and equipment is included, along with a description of the mechanics of the rowing stroke. This information is necessary in order to make an accurate diagnosis and treatment protocol for these injuries, which are mainly chronic in nature. The most frequently injured region is the low back, mainly due to excessive hyperflexion and twisting, and can include specific injuries such as spondylolysis, sacroiliac joint dysfunction and disc herniation. Rib stress fractures account for the most time lost from on-water training and competition. Although theories abound for the mechanism of injury, the exact aetiology of rib stress fractures remains unknown. Other injuries discussed within, which are specific to ribs, include costochondritis, costovertebral joint subluxation and intercostal muscle strains. Shoulder pain is quite common in rowers and can be the result of overuse, poor technique, or tension in the upper body. Injuries concerning the forearm and wrist are also common, and can include exertional compartment syndrome, lateral epicondylitis, deQuervain's and intersection syndrome, and tenosynovitis of the wrist extensors. In the lower body, the major injuries reported include generalised patellofemoral pain due to abnormal patellar tracking, and iliotibial band friction syndrome. Lastly, dermatological issues, such as blisters and abrasions, and miscellaneous issues, such as environmental concerns and the female athlete triad, are also included in this article.Pathophysiology, mechanism of injury, assessment and management strategies are outlined in the text for each injury, with special attention given to ways to correct

  1. A comparison of cylindrical and row trenched cooling holes with alignment angle of 0 degree near the combustor endwall

    NASA Astrophysics Data System (ADS)

    Kianpour, E.; Nor Azwadi, C. S.; Golshokouh, I.

    2013-12-01

    We studied the effects of cylindrical and row trenched cooling holes with alignment angle of 0° at BR=3.18 on the film cooling performance near the endwall surface of a combustor simulator. In this research, a three-dimensional presentation of gas turbine engine was simulated and analyzed with a commercial finite volume package FLUENT 6.2.26 to gain fundamental data. The current study has been performed with Reynolds-averaged Navier-Stokes turbulence model (RANS) on internal cooling passages. This combustor simulator combined the interaction of two rows of dilution jets, which were staggered in the stream wise direction and aligned in the span wise direction. The entire findings of the study declared that with using the row trenched holes near the enwall surface; film cooling effectiveness is doubled compared to the cooling performance of baseline case.

  2. Planting date rate and twin-row vs single-row soybean in the mid south

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Comparisons of twin-row vs. single-row production of an irrigated MG IV soybean (Glycine max (L.) Merr.) on a sandy loam soil and a clay indigenous to the Mississippi Delta were conducted in 2009 to 2010 at Stoneville, MS. Seeding rates of 20, 30, 40, and 50 seed m-2 were planted in four row plots ...

  3. Helical 4D CT and Comparison with Cine 4D CT

    NASA Astrophysics Data System (ADS)

    Pan, Tinsu

    4D CT was one of the most important developments in radiation oncology in the last decade. Its early development in single slice CT and commercialization in multi-slice CT has radically changed our practice in radiation treatment of lung cancer, and has enabled the stereotactic radiosurgery of early stage lung cancer. In this chapter, we will document the history of 4D CT development, detail the data sufficiency condition governing the 4D CT data collection; present the design of the commercial helical 4D CTs from Philips and Siemens; compare the differences between the helical 4D CT and the GE cine 4D CT in data acquisition, slice thickness, acquisition time and work flow; review the respiratory monitoring devices; and understand the causes of image artifacts in 4D CT.

  4. Comparisons of muscle oxygenation changes between arm and leg muscles during incremental rowing exercise with near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongxing; Wang, Bangde; Gong, Hui; Xu, Guodong; Nioka, Shoko; Chance, Britton

    2010-01-01

    Our purpose is to compare the changes in muscle oxygenation in the vastus lateralis (VL) and biceps brachii (BB) muscles simultaneously using near-infrared spectroscopy (NIRS) during incremental rowing exercise in eight rowers. Based on the BB and VL muscle oxygenation patterns, two points are used to characterize the muscle oxygenation kinetics in both the arm and the leg muscles. The first point is the breaking point (Bp), which refers to an accelerated fall in muscle oxygenation that correlates with the gas exchange threshold (GET). The second point is the leveling-off point (Lo), which suggests the upper limit of O2 extraction. The GET occurred at 63.3+/-2.4% of maximal oxygen uptake (V˙O2 max). The Bp appeared at 45.0+/-3.8% and 55.6+/-2.4% V˙O2 max in the BB and VL, respectively. The Lo appeared at 63.6+/-4.1% and 86.6+/-1.0% V˙O2 max in these two muscles, respectively. Both the Bp and the Lo occurred earlier in BB compared with VL. These results suggest that arm muscles have lower oxidative capacity than leg muscles during rowing exercise. The rowers with higher exercise performances showed heavier workloads, as evaluated by Bp and Lo. The monitoring of muscle oxygenation by NIRS in arm and leg muscles during rowing could be a useful guide for evaluation and training.

  5. The Impact of Different Levels of Adaptive Iterative Dose Reduction 3D on Image Quality of 320-Row Coronary CT Angiography: A Clinical Trial

    PubMed Central

    Feger, Sarah; Rief, Matthias; Zimmermann, Elke; Martus, Peter; Schuijf, Joanne Désirée; Blobel, Jörg; Richter, Felicitas; Dewey, Marc

    2015-01-01

    Purpose The aim of this study was the systematic image quality evaluation of coronary CT angiography (CTA), reconstructed with the 3 different levels of adaptive iterative dose reduction (AIDR 3D) and compared to filtered back projection (FBP) with quantum denoising software (QDS). Methods Standard-dose CTA raw data of 30 patients with mean radiation dose of 3.2 ± 2.6 mSv were reconstructed using AIDR 3D mild, standard, strong and compared to FBP/QDS. Objective image quality comparison (signal, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), contour sharpness) was performed using 21 measurement points per patient, including measurements in each coronary artery from proximal to distal. Results Objective image quality parameters improved with increasing levels of AIDR 3D. Noise was lowest in AIDR 3D strong (p≤0.001 at 20/21 measurement points; compared with FBP/QDS). Signal and contour sharpness analysis showed no significant difference between the reconstruction algorithms for most measurement points. Best coronary SNR and CNR were achieved with AIDR 3D strong. No loss of SNR or CNR in distal segments was seen with AIDR 3D as compared to FBP. Conclusions On standard-dose coronary CTA images, AIDR 3D strong showed higher objective image quality than FBP/QDS without reducing contour sharpness. Trial Registration Clinicaltrials.gov NCT00967876 PMID:25945924

  6. Primary hyperaldosteronism: comparison of CT, adrenal venography, and venous sampling

    SciTech Connect

    Geisinger, M.A.; Zelch, M.G.; Bravo, E.L.; Risius, B.F.; O'Donovan, P.B.; Borkowski, G.P.

    1983-08-01

    Twenty-nine patients with primary hyperaldosteronism were evaluated with computed tomography (CT), adrenal venous sampling, and adrenal venography. Twenty-three patients had aldosteronomas and six had bilateral adrenocortical hyperplasia. Sixteen (70%) of the adenomas were accurately located by CT. All nodules of 1.5 cm or larger diameter and 50% of nodules 1.0 to 1.4 cm in diameter were demonstrated. Nodules of less than 1.0 cm in diameter generally were not detected. High-resolution CT appeared more sensitive than standard CT (75% vs 58%). Adrenal venous sampling for aldosterone assay was the most sensitive of the three methods, localizing 22 (96%) of the 23 adenomas. Eighteen (78%) of the adenomas were identified by adrenal venography, although two patients with bilateral cortical hyperplasia were mistakenly diagnosed as having a small adenoma. No such false-positive studies were encountered with CT or adrenal venous sampling.

  7. Comparison of CT and MR-CT Fusion for Prostate Post-Implant Dosimetry

    SciTech Connect

    Maletz, Kristina L.; Ennis, Ronald D.; Ostenson, Jason; Pevsner, Alexander; Kagen, Alexander; Wernick, Iddo

    2012-04-01

    Purpose: The use of T2 MR for postimplant dosimetry (PID) after prostate brachytherapy allows more anatomically accurate and precise contouring but does not readily permit seed identification. We developed a reproducible technique for performing MR-CT fusion and compared the resulting dosimetry to standard CT-based PID. Methods and Materials: CT and T1-weighted MR images for 45 patients were fused and aligned based on seed distribution. The T2-weighted MR image was then fused to the aligned T1. Reproducibility of the fusion technique was tested by inter- and intraobserver variability for 13 patients. Dosimetry was computed for the prostate as a whole and for the prostate divided into anterior and posterior sectors of the base, mid-prostate, and apex. Results: Inter- and intraobserver variability for the fusion technique showed less than 1% variation in D90. MR-CT fusion D90 and CT D90 were nearly equivalent for the whole prostate, but differed depending on the identification of superior extent of the base (p = 0.007) and on MR/CT prostate volume ratio (p = 0.03). Sector analysis showed a decrease in MR-CT fusion D90 in the anterior base (ratio 0.93 {+-}0.25, p < 0.05) and an increase in MR-CT fusion D90 in the apex (p < 0.05). The volume of extraprostatic tissue encompassed by the V100 is greater on MR than CT. Factors associated with this difference are the MR/CT volume ratio (p < 0.001) and the difference in identification of the inferior extent of the apex (p = 0.03). Conclusions: We developed a reproducible MR-CT fusion technique that allows MR-based dosimetry. Comparing the resulting postimplant dosimetry with standard CT dosimetry shows several differences, including adequacy of coverage of the base and conformity of the dosimetry around the apex. Given the advantage of MR-based tissue definition, further study of MR-based dosimetry is warranted.

  8. Spinal Kinematics of Adolescent Male Rowers with Back Pain in Comparison with Matched Controls During Ergometer Rowing.

    PubMed

    Ng, Leo; Campbell, Amity; Burnett, Angus; Smith, Anne; O'Sullivan, Peter

    2015-12-01

    There is a high prevalence of low back pain (LBP) in adolescent male rowers. In this study, regional lumbar spinal kinematics and self-reported LBP intensity were compared between 10 adolescent rowers with moderate levels of LBP relating to rowing with 10 reporting no history of LBP during a 15-minute ergometer trial using an electromagnetic tracking system. Adolescent male rowers with LBP reported increasing pain intensity during ergometer rowing. No significant differences were detected in mean upper or lower lumbar angles between rowers with and without LBP. However, compared with rowers without pain, rowers with pain: (1) had relatively less excursion of the upper lumbar spine into extension over the drive phase, (2) had relatively less excursion of the lower lumbar spine into extension over time, (3) had greater variability in upper and lower lumbar angles over the 15-minute ergometer trial, (4) positioned their upper lumbar spine closer to end range flexion for a greater proportion of the drive phase, and (5) showed increased time in sustained flexion loading in the upper lumbar spine. Differences in regional lumbar kinematics exist between adolescent male rowers with and without LBP, which may have injury implication and intervention strategies. PMID:26252195

  9. Follow-up of Wilms tumor: comparison of CT with other imaging procedures

    SciTech Connect

    Brasch, R.C.; Randel, S.B.; Gould, R.G.

    1981-11-01

    In a retrospective review, computed tomography (CT) was compared to a ''routine'' combination of other diagnostic imaging procedures used for follow-up evaluations of 13 children being treated for Wilms tumor. The examined variables were diagnostic accuracy, expense, and duration of examination. Results from 13 patients indicated that CT most accurately answers diagnostic queries pertinent to follow-up evaluation of Wilms tumors: the presence and extent of bilateral renal tumors, local recurrence, contralateral renal hypertrophy, and metastasis to liver or lungs. For diagnosing pulmonary metastases, CT was superior to conventional chest radiography both in sensitivity (4/4 vs. 2/4) and specificity (9/9 vs. 6/9). In depiction of liver metastases, CT (3/3) was superior to liver scintigraphy (2/3). The extent of bilateral Wilms tumors was better defined by CT than by urography. In no instances were the alternative diagnostic imaging studies found to be more accurate than CT for the detection of recurrent tumor. Average cost for a CT examination ($344) is considerably less than the cost for a routine combination of the other imaging studies ($594). Examination time and diagnostic radiation doses are also reduced using CT. Pending larger comparison studies, CT is recommended as the primary diagnostic method for follow-up evaluation of patients with Wilms tumor.

  10. Preoperative Gross Classification of Gastric Adenocarcinoma: Comparison of Double Contrast-Enhanced Ultrasound and Multi-Detector Row CT.

    PubMed

    Yan, Caoxin; Bao, Xiaofeng; Shentu, Weihui; Chen, Jian; Liu, Chunmei; Ye, Qin; Wang, Liuhong; Tan, Yangbin; Huang, Pintong

    2016-07-01

    The aim of this study was to compare the accuracy of multi-detector computed tomography (MDCT) with double contrast-enhanced ultrasound (DCEUS), in which intravenous microbubbles are used alongside oral contrast-enhanced ultrasound, in determining the gross classification of patients with gastric carcinoma (GC). Altogether, 239 patients with GC proved by histology after endoscopic biopsy were included in this study. DCEUS and MDCT were performed pre-operatively. The diagnostic accuracies of DCEUS and MDCT in determining the gross classification were calculated and compared. The overall accuracy of DCEUS in determining the gross appearance of GC was higher than that of MDCT (84.9% vs. 79.9%, p < 0.001). There was no significant difference in accuracy between DCEUS and MDCT for Borrmann I and IV classifications of advanced gastric cancer (χ(2), p = 0.323 for Borrmann type I, p = 0.141 for Borrmann type IV). The accuracy of DCEUS for early GC and Borrmann II and III classifications of GC was higher than that of MDCT (χ(2), p = 0.000 for all). DCEUS may be regarded as a valuable complementary tool to MDCT in determining the gross appearance of gastric adenocarcinoma pre-operatively. PMID:27072076

  11. A Comparison of Density Functional Theory with Ab initio Approaches for Systems Involving First Transition Row Metals

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Bauschlicher, Charles W.; Langhoff, Stephen R. (Technical Monitor)

    1994-01-01

    Density functional theory (DFT) is found to give a better description of the geometries and vibrational frequencies of FeL and FeL(sup +) systems than second order Moller Plesset perturbation theory (MP2). Namely, the DFT correctly predicts the shift in the CO vibrational frequency between free CO and the Sigma(sup -) state of FeCO and yields a good result for the Fe-C distance in the quartet states of FeCH4(+) 4 These are properties where the MP2 results are unsatisfactory. Thus DFT appears to be an excellent approach for optimizing the geometries and computing the zero-point energies of systems containing first transition row atoms. Because the DFT approach is biased in favor of the 3d(exp 7) occupation, whereas the more traditional approaches are biased in favor of the 3d(exp 6) occupation, differences are found in the relative ordering of states. It is shown that if the dissociation is computed to the most appropriate atomic asymptote and corrected to the ground state asymptote using the experimental separations, the DFT results are in good agreement with high levels of theory. The energetics at the DFT level are much superior to the MP2 and in most cases in good agreement with high levels of theory.

  12. Comparison of Reconstruction Intervals in Routine ECG-Pulsed 64-Row-MSCT Coronary Angiography in Frequency Controlled Patients

    SciTech Connect

    Frydrychowicz, Alex Pache, Gregor; Saueressig, Ulrich; Foell, Daniela; Kotter, Elmar; Langer, Mathias; Bley, Thorsten A.

    2007-02-15

    Purpose. In light of the increasing use and acceptance of multislice computed tomography (MSCT) coronary angiography it was the purpose of this study to compare reconstruction intervals used in a routine ECG-pulsed MSCT coronary artery angiography setting with frequency controlled patients. Methods. Examinations were performed on a Siemens Somatom Sensation 64 scanner with a total of 110 ml of contrast agent and ECG pulsing (interval from 40% to 70%) after oral application of a {beta}-blocker if the heart rate was higher than 65 bpm. All human subjects were referred for the evaluation of suspected coronary artery disease. Coronary artery segments were evaluated by two experienced radiologists in a consensus reading. A ranking of diagnostic image quality (from 1 (no evaluation possible) to 5 (excellent image quality)) was statistically evaluated by Wilcoxon Signed Rank Test. Results. In 45 patients (30 male, 15 female, age 63.8 {+-} 12.1 years) we detected a significant advantage of the 60% reconstruction interval over 40%, 50%, and 70% (for each p < 0.05). In cases of sudden arrhythmia or movement during the scan, additional reconstruction intervals within the ECG-pulsed reconstruction intervals remained necessary for diagnosis. Conclusion. In a routine diagnostic setting with frequency controlled patients and ECG pulsing the 60% reconstruction interval can be considered superior for the initial diagnosis in 64-row multislice computed tomography coronary angiography. However, further information can be derived from various reconstruction intervals such as 40% and 70%.

  13. Comparison between x-ray tube-based and synchrotron radiation-based μCT

    NASA Astrophysics Data System (ADS)

    Brunke, Oliver; Brockdorf, Kathleen; Drews, Susanne; Müller, Bert; Donath, Tilman; Herzen, Julia; Beckmann, Felix

    2008-08-01

    Nowadays, X-ray tube-based high-resolution CT systems are widely used in scientific research and industrial applications. But the potential, convenience and economy of these lab systems is often underestimated. The present paper shows the comparison of sophisticated conventional μCT with synchrotron radiation-based μCT (SRμCT). The different aspects and characteristics of both approaches like spatial and density resolution, penetration depth, scanning time or sample size is described in detail. The tube-based μCT measurements were performed with a granite-based nanotom®-CT system (phoenix|x-ray, Wunstorf, Germany) equipped with a 180 kV - 15 W high-power nanofocus® tube with tungsten or molybdenum targets. The tube offers a wide range of applications from scanning low absorbing samples in nanofocus® mode with voxel sizes below 500 nm and highly absorbing objects in the high power mode with focal spot and voxel sizes of a few microns. The SRμCT measurements were carried out with the absorption contrast set-up at the beamlines W 2 and BW 2 at HASYLAB/DESY, operated by the GKSS Research Center. The range of samples examined covers materials of very different absorption levels and related photon energies for the CT scans. Both quantitative and qualitative comparisons of CT scans using biomedical specimens with rather low X-ray absorption such as parts of the human spine as well as using composites from the field of materials science are shown.

  14. Designing ROW Methods

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    1996-01-01

    There are many aspects to consider when designing a Rosenbrock-Wanner-Wolfbrandt (ROW) method for the numerical integration of ordinary differential equations (ODE's) solving initial value problems (IVP's). The process can be simplified by constructing ROW methods around good Runge-Kutta (RK) methods. The formulation of a new, simple, embedded, third-order, ROW method demonstrates this design approach.

  15. Row fault detection system

    DOEpatents

    Archer, Charles Jens; Pinnow, Kurt Walter; Ratterman, Joseph D.; Smith, Brian Edward

    2012-02-07

    An apparatus, program product and method check for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

  16. Row fault detection system

    DOEpatents

    Archer, Charles Jens; Pinnow, Kurt Walter; Ratterman, Joseph D.; Smith, Brian Edward

    2010-02-23

    An apparatus and program product check for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

  17. Row fault detection system

    SciTech Connect

    Archer, Charles Jens; Pinnow, Kurt Walter; Ratterman, Joseph D.; Smith, Brian Edward

    2008-10-14

    An apparatus, program product and method checks for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

  18. Comparison of stroke infarction between CT perfusion and diffusion weighted imaging: preliminary results

    NASA Astrophysics Data System (ADS)

    Abd. Rahni, Ashrani Aizzuddin; Arka, Israna Hossain; Chellappan, Kalaivani; Mukari, Shahizon Azura; Law, Zhe Kang; Sahathevan, Ramesh

    2016-03-01

    In this paper we present preliminary results of comparison of automatic segmentations of the infarct core, between that obtained from CT perfusion (based on time to peak parameter) and diffusion weighted imaging (DWI). For each patient, the two imaging volumes were automatically co-registered to a common frame of reference based on an acquired CT angiography image. The accuracy of image registration is measured by the overlap of the segmented brain from both images (CT perfusion and DWI), measured within their common field of view. Due to the limitations of the study, DWI was acquired as a follow up scan up to a week after initial CT based imaging. However, we found significant overlap of the segmented brain (Jaccard indices of approximately 0.8) and the percentage of infarcted brain tissue from the two modalities were still fairly highly correlated (correlation coefficient of approximately 0.9). The results are promising with more data needed in future for clinical inference.

  19. INTERIOR SECOND FLOOR EAST END LOOKING WEST AT NORTH ROW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR SECOND FLOOR- EAST END LOOKING WEST AT NORTH ROW OF MUSHROOM COLUMNS. - Colt Fire Arms Company, South Armory Building, 36-150 Huyshope Avenue, 17-170 Van Dyke Avenue, 49 Vredendale Avenue, Hartford, Hartford County, CT

  20. 4. VIEW NORTHWEST, INTERIOR OF GATEHOUSE, SHOWING ROW OF GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW NORTHWEST, INTERIOR OF GATEHOUSE, SHOWING ROW OF GATE OPERATING MECHANISMS; HEIGHT OF STEMS INDICATES FOREGROUND GATE IS OPEN - Norwich Water Power Company, Headgates, West bank of Shetucket River opposite Fourteenth Street, Greenville section, Norwich, New London County, CT

  1. The relevance of image quality indices for dose optimization in abdominal multi-detector row CT in children: experimental assessment with pediatric phantoms

    NASA Astrophysics Data System (ADS)

    Brisse, H. J.; Brenot, J.; Pierrat, N.; Gaboriaud, G.; Savignoni, A.; DeRycke, Y.; Neuenschwander, S.; Aubert, B.; Rosenwald, J.-C.

    2009-04-01

    This study assessed and compared various image quality indices in order to manage the dose of pediatric abdominal MDCT protocols and to provide guidance on dose reduction. PMMA phantoms representing average body diameters at birth, 1 year, 5 years, 10 years and 15 years of age were scanned in a four-channel MDCT with a standard pediatric abdominal CT protocol. Image noise (SD, standard deviation of CT number), noise derivative (ND, derivative of the function of noise with respect to dose) and contrast-to-noise ratio (CNR) were measured. The 'relative' low-contrast detectability (rLCD) was introduced as a new quantity to adjust LCD to the various phantom diameters on the basis of the LCD1% assessed in a Catphan® phantom and a constant central absorbed dose. The required variations of CTDIvol16 with respect to phantom size were analyzed in order to maintain each image quality index constant. The use of a fixed SD or CNR level leads to major dose ratios between extreme patient sizes (factor 22.7 to 44 for SD, 31.7 to 51.5 for CNR2.8%), whereas fixed ND and rLCD result in acceptable dose ratios ranging between factors of 2.9 and 3.9 between extreme phantom diameters. For a 5-9 mm rLCD1%, adjusted ND values range between -0.84 and -0.11 HU mGy-1. Our data provide guidance on dose reduction on the basis of patient dimensions and the required rLCD (e.g., to get a constant 7 mm rLCD1% for abdominal diameters of 10, 13, 16, 20 and 25 cm, tube current-time product should be adjusted in order to obtain CTDIvol16 values of 6.2, 7.2, 8.8, 11.6 and 17.7 mGy, respectively).

  2. 32. TYPICAL BRYANT ITEMS FROM THE 1930S; TOP ROW LEFT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. TYPICAL BRYANT ITEMS FROM THE 1930S; TOP ROW LEFT TO RIGHT: PORCELAIN CASED SWITCH, ROTARY SWITCH, SHORTING PLUG TO BYPASS FUSE; SECOND ROW: BRASS INCANDESCENT LAMP SURFACE RECEPTACLE, INCANDESCENT LAMPHOLDER WITH ADAPTER FOR GLASS GLOBE; THIRD ROW: PORCELAIN BASE ROTARY SWITCH, APPLIANCE BREAKER WITH COVER REMOVED, APPLIANCE BREAKER - Bryant Electric Company, 1421 State Street, Bridgeport, Fairfield County, CT

  3. Diagnostic Phase of Calcium Scoring Scan Applied as the Center of Acquisition Window of Coronary Computed Tomography Angiography Improves Image Quality in Minimal Acquisition Window Scan (Target CTA Mode) Using the Second Generation 320-Row CT

    PubMed Central

    Maeda, Eriko; Kanno, Shigeaki; Ino, Kenji; Tomizawa, Nobuo; Akahane, Masaaki; Torigoe, Rumiko; Ohtomo, Kuni

    2016-01-01

    Objective. To compare the image quality of coronary computed tomography angiography (CCTA) acquired under two conditions: 75% fixed as the acquisition window center (Group 75%) and the diagnostic phase for calcium scoring scan as the center (CS; Group CS). Methods. 320-row cardiac CT with a minimal acquisition window (scanned using “Target CTA” mode) was performed on 81 patients. In Group 75% (n = 40), CS was obtained and reconstructed at 75% and the center of the CCTA acquisition window was set at 75%. In Group CS (n = 41), CS was obtained at 75% and the diagnostic phase showing minimal artifacts was applied as the center of the CCTA acquisition window. Image quality was evaluated using a four-point scale (4-excellent) and the mean scores were compared between groups. Results. The CCTA scan diagnostic phase occurred significantly earlier in CS (75.7 ± 3.2% vs. 73.6 ± 4.5% for Groups 75% and CS, resp., p = 0.013). The mean Group CS image quality score (3.58 ± 0.63) was also higher than that for Group 75% (3.19 ± 0.66, p < 0.0001). Conclusions. The image quality of CCTA in Target CTA mode was significantly better when the center of acquisition window is adjusted using CS. PMID:26977449

  4. Transcatheter Arterial Embolization Therapy for a Hypoplastic Pelvic Kidney with a Single Vaginal Ectopic Ureter to Control Incontinence: The Usefulness of Three-Dimensional CT Angiography Using Multidetector-Row Helical CT

    SciTech Connect

    Kudoh, Kouichi Kadota, Masataka; Nakayama, Yoshiharu; Imuta, Masanori; Yasuda, Tsuyoshi; Yamashita, Yasuyuki; Inadome, Akito; Yoshida, Masaki; Ueda, Shouichi

    2003-09-15

    A girl with continuous urinary incontinence was successfully treated by angiographic embolization of a hypoplastic pelvic kidney with a single unilateral vaginal ectopic opening of the ureter. For this intervention, CT angiography was useful for detecting the corresponding renal artery of the hypoplastic kidney.

  5. Comparison of CT-derived Ventilation Maps with Deposition Patterns of Inhaled Microspheres in Rats

    SciTech Connect

    Jacob, Rick E.; Lamm, W. J.; Einstein, Daniel R.; Krueger, Melissa; Glenny, Robb W.; Corley, Richard A.

    2015-04-01

    Purpose: Computer models for inhalation toxicology and drug-aerosol delivery studies rely on ventilation pattern inputs for predictions of particle deposition and vapor uptake. However, changes in lung mechanics due to disease can impact airflow dynamics and model results. It has been demonstrated that non-invasive, in vivo, 4DCT imaging (3D imaging at multiple time points in the breathing cycle) can be used to map heterogeneities in ventilation patterns under healthy and disease conditions. The purpose of this study was to validate ventilation patterns measured from CT imaging by exposing the same rats to an aerosol of fluorescent microspheres (FMS) and examining particle deposition patterns using cryomicrotome imaging. Materials and Methods: Six male Sprague-Dawley rats were intratracheally instilled with elastase to a single lobe to induce a heterogeneous disease. After four weeks, rats were imaged over the breathing cycle by CT then immediately exposed to an aerosol of ~1µm FMS for ~5 minutes. After the exposure, the lungs were excised and prepared for cryomicrotome imaging, where a 3D image of FMS deposition was acquired using serial sectioning. Cryomicrotome images were spatially registered to match the live CT images to facilitate direct quantitative comparisons of FMS signal intensity with the CT-based ventilation maps. Results: Comparisons of fractional ventilation in contiguous, non-overlapping, 3D regions between CT-based ventilation maps and FMS images showed strong correlations in fractional ventilation (r=0.888, p<0.0001). Conclusion: We conclude that ventilation maps derived from CT imaging are predictive of the 1µm aerosol deposition used in ventilation-perfusion heterogeneity inhalation studies.

  6. SUICIDE ON DEATH ROW.

    PubMed

    Tartaro, Christine; Lester, David

    2015-12-01

    For the period 1976-2011, the suicide rate on death rows in the United States was only weakly (and non-significantly) associated with the marriage, birth, divorce, and unemployment rates in the general population. Possible explanations for why social indicators in the larger society might be associated with the behavior of prisoners on death row were discussed. PMID:26595302

  7. The usefulness of F-18 FDG PET/CT-mammography for preoperative staging of breast cancer: comparison with conventional PET/CT and MR-mammography

    PubMed Central

    Moon, Eun-Ha; Lim, Seok Tae; Han, Yeon-Hee; Jeong, Young Jin; Kang, Yun-Hee; Jeong, Hwan-Jeong; Sohn, Myung-Hee

    2013-01-01

    Background The objective of the study was to compare the diagnostic efficacy of an integrated Fluorine-18 fluorodeoxyglucose (F-18 FDG) PET/CT-mammography (mammo-PET/CT) with conventional torso PET/CT (supine-PET/CT) and MR-mammography for initial assessment of breast cancer patients. Patients and methods Forty women (52.0 ± 12.0 years) with breast cancer who underwent supine-PET/CT, mammo-PET/CT, and MR-mammography from April 2009 to August 2009 were enrolled in the study. We compared the size of the tumour, tumour to chest wall distance, tumour to skin distance, volume of axillary fossa, and number of meta-static axillary lymph nodes between supine-PET/CT and mammo-PET/CT. Next, we assessed the difference of focality of primary breast tumour and tumour size in mammo-PET/CT and MR-mammography. Histopathologic findings served as the standard of reference. Results In the comparison between supine-PET/CT and mammo-PET/CT, significant differences were found in the tumour size (supine-PET/CT: 1.3 ± 0.6 cm, mammo-PET/CT: 1.5 ± 0.6 cm, p < 0.001), tumour to thoracic wall distance (1.8 ± 0.9 cm, 2.2 ± 2.1 cm, p < 0.001), and tumour to skin distance (1.5 ± 0.8 cm, 2.1 ± 1.4 cm, p < 0.001). The volume of axillary fossa was significantly wider in mammo-PET/CT than supine-PET/CT (21.7 ± 8.7 cm3 vs. 23.4 ± 10.4 cm3, p = 0.03). Mammo-PET/CT provided more correct definition of the T-stage of the primary tumour than did supine-PET/CT (72.5% vs. 67.5%). No significant difference was found in the number of metastatic axillary lymph nodes. Compared with MR-mammography, mammo-PET/CT provided more correct classification of the focality of lesion than did MR-mammography (95% vs. 90%). In the T-stage, 72.5% of cases with mammo-PET/CT and 70% of cases with MR-mammography showed correspondence with pathologic results. Conclusions Mammo-PET/CT provided more correct definition of the T-stage and evaluation of axillary fossa may also be delineated more clearly than with supine-PET/CT

  8. Biomechanics of Rowing

    NASA Astrophysics Data System (ADS)

    Hase, Kazunori; Kaya, Motoshi; Yamazaki, Nobutoshi; Andrews, Brian J.; Zavatsky, Amy B.; Halliday, Suzanne E.

    Compared with the other exercise, such as walking and cycling, rowing was expected to have some fitness advantage, while there were some misgivings about the risk of injury. The objectives of this study were to quantify biomechanical characteristics of rowing for fitness and rehabilitation and to offer normative data for the prevention of injury and for determining effective exercise. An experiment was performed to collect the kinematic and kinetic data during rowing by experienced and non-experienced subjects. A three-dimensional whole-body musculo-skeletal model was used to calculate the biomechanical loads, such as the joint moments, the muscular tensions, the joint contact forces and the energy consumption. The results of this study indicate that rowing is an effective exercise for rehabilitation and fitness. However, the non-experienced rower should acquire considerable skill to obtain sufficient exercise. The rowing cadence should be decided according to the purpose of the exercise.

  9. A comparison of sampling strategies for dual energy micro-CT

    NASA Astrophysics Data System (ADS)

    Guo, Xiaolian; Johnston, Samuel M.; Johnson, G. Allan; Badea, Cristian T.

    2012-03-01

    Micro-CT has become a powerful tool for small animal research. Many micro-CT applications require exogenous contrast agents, which are most commonly based on iodine. Despite advancements in contrast agents, single-energy micro-CT is sometimes limited in the separation of two different materials that share similar grayscale intensity values as in the case of bone and iodine. Dual energy micro-CT offers a solution to this separation problem, while eliminating the need for pre-injection scanning. Various dual energy micro-CT sampling strategies are possible, including 1) single source sequential scanning, 2) simultaneous dual source acquisition, or 3) single source with kVp switching. But, no commercial micro-CT system exists in which all these sampling strategies have been implemented. This study reports on the implementation and comparison of these scanning techniques on the same small animal imaging system. Furthermore, we propose a new sampling strategy that combines dual source and kVp switching. Post-sampling and reconstruction, a simple two-material dual energy decomposition was applied to differentiate iodine from bone. The results indicate the time differences and the potential problems associated with each sampling strategy. Dual source scanning allows for the fastest acquisition, but is prone to errors in decomposition associated with scattering and imperfect geometric alignment of the two imaging chains. KVp switching prevents these types of artifacts, but requires more time for sampling. The novel combination between the dual source and kVp switching has the potential to reduce sampling time and provide better decomposition performance.

  10. Evaluation of the ΔV 4D CT ventilation calculation method using in vivo xenon CT ventilation data and comparison to other methods.

    PubMed

    Zhang, Geoffrey G; Latifi, Kujtim; Du, Kaifang; Reinhardt, Joseph M; Christensen, Gary E; Ding, Kai; Feygelman, Vladimir; Moros, Eduardo G

    2016-01-01

    Ventilation distribution calculation using 4D CT has shown promising potential in several clinical applications. This study evaluated the direct geometric ventilation calculation method, namely the ΔV method, with xenon-enhanced CT (XeCT) ventilation data from four sheep, and compared it with two other published meth-ods, the Jacobian and the Hounsfield unit (HU) methods. Spearman correlation coefficient (SCC) and Dice similarity coefficient (DSC) were used for the evaluation and comparison. The average SCC with one standard deviation was 0.44 ± 0.13 with a range between 0.29 and 0.61 between the XeCT and ΔV ventilation distributions. The average DSC value for lower 30% ventilation volumes between the XeCT and ΔV ventilation distributions was 0.55 ± 0.07 with a range between 0.48 and 0.63. Ventilation difference introduced by deformable image registration errors improved with smoothing. In conclusion, ventilation distributions generated using ΔV-4D CT and deformable image registration are in reasonably agreement with the in vivo XeCT measured ventilation distribution. PMID:27074479

  11. A retrospective comparison of smart prep and test bolus multi-detector CT pulmonary angiography protocols

    SciTech Connect

    Suckling, Tara; Smith, Tony; Reed, Warren

    2013-06-15

    Optimal arterial opacification is crucial in imaging the pulmonary arteries using computed tomography (CT). This poses the challenge of precisely timing data acquisition to coincide with the transit of the contrast bolus through the pulmonary vasculature. The aim of this quality assurance exercise was to investigate if a change in CT pulmonary angiography (CTPA) scanning protocol resulted in improved opacification of the pulmonary arteries. Comparison was made between the smart prep protocol (SPP) and the test bolus protocol (TBP) for opacification in the pulmonary trunk. A total of 160 CTPA examinations (80 using each protocol) performed between January 2010 and February 2011 were assessed retrospectively. CT attenuation coefficients were measured in Hounsfield Units (HU) using regions of interest at the level of the pulmonary trunk. The average pixel value, standard deviation (SD), maximum, and minimum were recorded. For each of these variables a mean value was then calculated and compared for these two CTPA protocols. Minimum opacification of 200 HU was achieved in 98% of the TBP sample but only 90% of the SPP sample. The average CT attenuation over the pulmonary trunk for the SPP was 329 (SD = ±21) HU, whereas for the TBP it was 396 (SD = ±22) HU (P = 0.0017). The TBP also recorded higher maximum (P = 0.0024) and minimum (P = 0.0039) levels of opacification. This study has found that a TBP resulted in significantly better opacification of the pulmonary trunk than the SPP.

  12. Photon counting spectral CT versus conventional CT: comparative evaluation for breast imaging application

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.; Fritz, Shannon G.

    2011-04-01

    Spectral CT systems with photon counting detectors have more advantages compared to conventional CT systems. However, clinical applications have been hampered for a long time due to the high demands of clinical systems and limitations of spectroscopic x-ray detectors. Photon counting detector technology has gained considerable improvements in the past decade, and spectral CT has become a hot topic. Several experimental spectral CT systems are under investigation. The purpose of this work was to perform the first direct, side-by-side comparison of existing spectral CT technology with a mature clinical CT system based on a conventional energy integrating detector. We have built an experimental spectral CT system whose main parameters are similar to the parameters of a clinical CT system. The system uses a spectroscopic cadmium zinc telluride (CZT) detector. The detector includes two rows of CZT pixels with 256 pixels in each row. The pixel size is 1 × 1 mm2, and the maximum count rate is 2 Mcounts/pixel/s. The spectral CT system has a magnification factor of 1.62 and the source to detector and source to image distances of 85 and 53 cm, respectively. The above parameters are similar to those of the clinical CT system, Siemens Sensation 16, used for comparison. The two systems were compared by imaging spatial resolution and contrast resolution phantoms made from acrylic cylinders with 14 cm diameters. The resolution phantom included Al wires with 0.3, 0.6, and 1 mm diameters, and 0.25 g cc-1 CaCO3 contrast. The contrast phantom included contrast elements with 1.7, 5, and 15 mg cc-1 iodine, and 1.1, 3.3, and 10 mg cc-1 gadolinium. The phantoms were imaged with the two systems using 120 kVp tube voltage and 470 mR total skin exposure. The spectral CT showed CT numbers, image noise, and spatial and contrast resolutions to be similar within 10% compared to the Siemens 16 system, and provided an average of 10% higher CNR. However, the spectral CT system had a major

  13. Comparison of volumetric breast density estimations from mammography and thorax CT

    NASA Astrophysics Data System (ADS)

    Geeraert, N.; Klausz, R.; Cockmartin, L.; Muller, S.; Bosmans, H.; Bloch, I.

    2014-08-01

    Breast density has become an important issue in current breast cancer screening, both as a recognized risk factor for breast cancer and by decreasing screening efficiency by the masking effect. Different qualitative and quantitative methods have been proposed to evaluate area-based breast density and volumetric breast density (VBD). We propose a validation method comparing the computation of VBD obtained from digital mammographic images (VBDMX) with the computation of VBD from thorax CT images (VBDCT). We computed VBDMX by applying a conversion function to the pixel values in the mammographic images, based on models determined from images of breast equivalent material. VBDCT is computed from the average Hounsfield Unit (HU) over the manually delineated breast volume in the CT images. This average HU is then compared to the HU of adipose and fibroglandular tissues from patient images. The VBDMX method was applied to 663 mammographic patient images taken on two Siemens Inspiration (hospL) and one GE Senographe Essential (hospJ). For the comparison study, we collected images from patients who had a thorax CT and a mammography screening exam within the same year. In total, thorax CT images corresponding to 40 breasts (hospL) and 47 breasts (hospJ) were retrieved. Averaged over the 663 mammographic images the median VBDMX was 14.7% . The density distribution and the inverse correlation between VBDMX and breast thickness were found as expected. The average difference between VBDMX and VBDCT is smaller for hospJ (4%) than for hospL (10%). This study shows the possibility to compare VBDMX with the VBD from thorax CT exams, without additional examinations. In spite of the limitations caused by poorly defined breast limits, the calibration of mammographic images to local VBD provides opportunities for further quantitative evaluations.

  14. Comparison of CT and PET-CT based planning of radiation therapy in locally advanced pancreatic carcinoma

    PubMed Central

    Topkan, Erkan; Yavuz, Ali A; Aydin, Mehmet; Onal, Cem; Yapar, Fuat; Yavuz, Melek N

    2008-01-01

    Background To compare computed tomography (CT) with co-registered positron emission tomography-computed tomography (PET-CT) as the basis for delineating gross tumor volume (GTV) in unresectable, locally advanced pancreatic carcinoma (LAPC). Methods Fourteen patients with unresectable LAPC had both CT and PET images acquired. For each patient, two three-dimensional conformal plans were made using the CT and PET-CT fusion data sets. We analyzed differences in treatment plans and doses of radiation to primary tumors and critical organs. Results Changes in GTV delineation were necessary in 5 patients based on PET-CT information. In these patients, the average increase in GTV was 29.7%, due to the incorporation of additional lymph node metastases and extension of the primary tumor beyond that defined by CT. For all patients, the GTVCT versus GTVPET-CT was 92.5 ± 32.3 cm3 versus 104.5 ± 32.6 cm3 (p = 0.009). Toxicity analysis revealed no clinically significant differences between two plans with regard to doses to critical organs. Conclusion Co-registration of PET and CT information in unresectable LAPC may improve the delineation of GTV and theoretically reduce the likelihood of geographic misses. PMID:18808725

  15. Level set algorithms comparison for multi-slice CT left ventricle segmentation

    NASA Astrophysics Data System (ADS)

    Medina, Ruben; La Cruz, Alexandra; Ordoñes, Andrés.; Pesántez, Daniel; Morocho, Villie; Vanegas, Pablo

    2015-12-01

    The comparison of several Level Set algorithms is performed with respect to 2D left ventricle segmentation in Multi-Slice CT images. Five algorithms are compared by calculating the Dice coefficient between the resulting segmentation contour and a reference contour traced by a cardiologist. The algorithms are also tested on images contaminated with Gaussian noise for several values of PSNR. Additionally an algorithm for providing the initialization shape is proposed. This algorithm is based on a combination of mathematical morphology tools with watershed and region growing algorithms. Results on the set of test images are promising and suggest the extension to 3{D MSCT database segmentation.

  16. Comparison of manual and automatic MR-CT registration for radiotherapy of prostate cancer.

    PubMed

    Korsager, Anne Sofie; Carl, Jesper; Riis Østergaard, Lasse

    2016-01-01

    In image-guided radiotherapy (IGRT) of prostate cancer, delineation of the clini-cal target volume (CTV) often relies on magnetic resonance (MR) because of its good soft-tissue visualization. Registration of MR and computed tomography (CT) is required in order to add this accurate delineation to the dose planning CT. An automatic approach for local MR-CT registration of the prostate has previously been developed using a voxel property-based registration as an alternative to a manual landmark-based registration. The aim of this study is to compare the two registration approaches and to investigate the clinical potential for replacing the manual registration with the automatic registration. Registrations and analysis were performed for 30 prostate cancer patients treated with IGRT using a Ni-Ti prostate stent as a fiducial marker. The comparison included computing translational and rotational differences between the approaches, visual inspection, and computing the overlap of the CTV. The computed mean translational difference was 1.65, 1.60, and 1.80mm and the computed mean rotational difference was 1.51°, 3.93°, and 2.09° in the superior/inferior, anterior/posterior, and medial/lateral direction, respectively. The sensitivity of overlap was 87%. The results demonstrate that the automatic registration approach performs registrations comparable to the manual registration. PMID:27167285

  17. Scottish Short Stone Rows

    NASA Astrophysics Data System (ADS)

    Ruggles, Clive L. N.

    Short stone rows received a good deal of attention during the 1980s and 1990s, at a time when archaeoastronomy in prehistoric Britain and Ireland was moving beyond reassessments of Alexander Thom's "megalithic observatories" by identifying coherent groups of similar monuments with clear orientation trends. Many such rows are found in western Scotland, with the main concentration in Argyll and the island of Mull. Systematic analyses of their orientations produced credible evidence of an awareness of the 18.6-year lunar node cycle, within a "primary-secondary" pattern whereby isolated rows were oriented close to moonrise or moonset at the southern major standstill limit, while others oriented in this way were accompanied by a second row oriented in a declination range that could be interpreted either as lunar or solar. A detailed investigation of the landscape situation of the sites in northern Mull, accompanied by excavations at two of the sites, suggested that they were deliberately placed in locations where critical moonsets would be seen against prominent distant landscape features, but where the distant horizon in most or all other directions was hidden from view. A lack of independent archaeological evidence may help to explain why archaeoastronomical investigations at short stone rows have never progressed beyond "data-driven" studies of orientations and landscape situation. Nonetheless, the work that was done at these sites raised important general methodological issues, and pioneered techniques, that remain relevant across archaeoastronomy today.

  18. A comparison of four algorithms for metal artifact reduction in CT imaging

    NASA Astrophysics Data System (ADS)

    Golden, Caroline; Mazin, Samuel R.; Boas, F. Edward; Tye, Grace; Ghanouni, Pejman; Gold, Garry; Sofilos, Marc; Pelc, Norbert J.

    2011-03-01

    Streak artifacts caused by the presence of metal have been a significant problem in CT imaging since its inception in 1972. With the fast evolving medical device industry, the number of metal objects implanted in patients is increasing annually. This correlates directly with an increased likelihood of encountering metal in a patient CT scan, thus necessitating the need for an effective and reproducible metal artifact reduction (MAR) algorithm. Previous comparisons between MAR algorithms have typically only evaluated a small number of patients and a limited range of metal implants. Although the results of many methods are promising, the reproducibility of these results is key to providing more tangible evidence of their effectiveness. This study presents a direct comparison between the performances, assessed by board certified radiologists, of four MAR algorithms: 3 non-iterative and one iterative method, all applied and compared to the original clinical images. The results of the evaluation indicated a negative mean score in almost all uses for two of the non-iterative methods, signifying an overall decrease in the diagnostic quality of the images, generally due to perceived loss of detail. One non-iterative algorithm showed a slight improvement. The iterative algorithm was superior in all studies by producing a considerable improvement in all uses.

  19. Biomechanics of Rowing

    NASA Astrophysics Data System (ADS)

    Hase, Kazunori; Andrews, Brian J.; Zavatsky, Amy B.; Halliday, Suzanne E.

    A new control model for the study of biomechanical simulation of human movement was investigated using rowing as an example. The objectives were to explore biological and mechanical alternatives to optimal control methods. The simulation methods included simple control mechanisms based on proportional and derivative (PD) control, consideration of a simple neural model, introduction of an inverse dynamics system for feedback, and computational adjustment of control parameters by using an evaluative criterion and optimization method. By using simulation, appropriate rowing motions were synthesized. The generated rowing motion was periodic, continuous, and adaptable so that the pattern was stable against the mechanical force and independent of the initial condition. We believe that the simulation model is not only practical as a computational research tool from a biomechanical-engineering viewpoint but also significant from the point of view of fundamental biological theories of movement.

  20. Comparison of gonadal radiation doses from CT enterography and small-bowel follow-through in pediatric patients.

    PubMed

    Reid, Janet R; Pozzuto, Jessica; Morrison, Stuart; Obuchowski, Nancy; Davros, William

    2015-03-01

    OBJECTIVE. CT enterography is superior to small-bowel follow-through (SBFT) for diagnosis of inflammatory bowel disease (IBD). It is widely assumed that the radiation dose from CT enterography is greater than that from SBFT in the pediatric patient. This study was designed to compare gonadal doses from CT enterography and SBFT to verify the best imaging choice for IBD evaluation in children. This study also challenges the assumption that CT enterography imparts a higher radiation dose through comparison of calculated radiation doses from CT enterography and SBFT. MATERIALS AND METHODS. Patients 0-18 years old who underwent either CT enterography or SBFT over a 2-year period were included. The CT enterography group consisted of 39 boys and 51 girls, whereas the SBFT group consisted of 89 boys and 113 girls. CT enterography was performed at 120 kVp and approximately 132 mAs (range, 54-330 mAs) using weight-based protocols. SBFT used automated control of kilovoltage and tube current-exposure time product. Patient demographics and technical parameters were collected for CT enterography and SBFT, data were cross-paired between CT enterography and SBFT, and gonadal dose was calculated. RESULTS. Mean (± SD) CT enterography testis and ovarian doses were 0.93 ± 0.3 cGy (n = 39) and 0.64 ± 0.2 cGy (n = 51), respectively. Mean SBFT testis and ovarian doses were 2.3 ± 1.6 cGy (n = 89) and 1.49 ± 0.3 cGy (n = 113), respectively. Mean fluoroscopy time for SBFT was 2.6 ± 2 minutes. Gonadal dose for CT enterography was significantly lower than that for SBFT in boys and girls (p < 0.001). SBFT dose was lower in girls than boys (p < 0.001), whereas CT enterography dose was higher in boys than girls (p < 0.001). CONCLUSION. Gonadal dose for CT enterography was lower than that for SBFT for boys and girls of all sizes and age. Controlled exposure time made CT enterography dose more consistent, whereas the range of dose for SBFT was highly operator dependent and related to extent

  1. Imaging lobular breast carcinoma: comparison of synchrotron radiation DEI-CT technique with clinical CT, mammography and histology

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Bravin, A.; Keyriläinen, J.; Fernández, M.; Suortti, P.; Thomlinson, W.; Tenhunen, M.; Virkkunen, P.; Karjalainen-Lindsberg, M.-L.

    2004-01-01

    Different modalities for imaging cancer-bearing breast tissue samples are described and compared. The images include clinical mammograms and computed tomography (CT) images, CT images with partly coherent synchrotron radiation (SR), and CT and radiography images taken with SR using the diffraction enhanced imaging (DEI) method. The images are evaluated by a radiologist and compared with histopathological examination of the samples. Two cases of lobular carcinoma are studied in detail. The indications of cancer are very weak or invisible in the conventional images, but the morphological changes due to invasion of cancer become pronounced in the images taken by the DEI method. The strands penetrating adipose tissue are seen clearly in the DEI-CT images, and the histopathology confirms that some strands contain the so-called 'Indian file' formations of cancer cells. The radiation dose is carefully measured for each of the imaging modalities. The mean glandular dose (MGD) for 50% glandular breast tissue is about 1 mGy in conventional mammography and less than 0.25 mGy in projection DEI, while in the clinical CT imaging the MGD is very high, about 45 mGy. The entrance dose of 95 mGy in DEI-CT imaging gives rise to an MGD of 40 mGy, but the dose may be reduced by an order of magnitude, because the contrast is very large in most images.

  2. Validity of the size-specific dose estimate in adults undergoing coronary CT angiography: comparison with the volume CT dose index.

    PubMed

    Kidoh, Masafumi; Utsunomiya, Daisuke; Oda, Seitaro; Funama, Yoshinori; Yuki, Hideaki; Nakaura, Takeshi; Kai, Noriyuki; Nozaki, Takeshi; Yamashita, Yasuyuki

    2015-12-01

    Size-specific dose estimate (SSDE) takes into account the patient size but remains to be fully validated for adult coronary computed tomography angiography (CCTA). We investigated the appropriateness of SSDE for accurate estimation of patient dose by comparing the SSDE and the volume CT dose index (CTDIvol) in adult CCTA. This prospective study received institutional review board approval, and informed consent was obtained from each patient. We enrolled 37 adults who underwent CCTA with a 320-row CT. High-sensitivity metal oxide semiconductor field effect transistor dosimeters were placed on the anterior chest. CTDIvol reported by the scanner based on a 32-cm phantom was recorded. We measured chest diameter to convert CTDIvol to SSDE. Using linear regression, we then correlated SSDE with the mean measured skin dose. We also performed linear regression analyses between the skin dose/CTDIvol and the body mass index (BMI), and the skin dose/SSDE and BMI. There was a strong linear correlation (r = 0.93, P < 0.001) between SSDE (mean 37 ± 22 mGy) and mean skin dose (mean 17.7 ± 10 mGy). There was a moderate negative correlation between the skin dose/CTDIvol and BMI (r = 0.45, P < 0.01). The skin dose/SSDE was not affected by BMI (r = 0.06, P > 0.76). SSDE yields a more accurate estimation of the radiation dose without estimation errors attributable to the body size of adult patients undergoing CCTA. PMID:26440660

  3. Local variations in bone mineral density: a comparison of OCT versus x-ray micro-CT

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadya; Stevens-Smith, Jenna; Scutt, Andrew; Matcher, Stephen J.

    2008-02-01

    We describe variations in the degree of mineralisation within the subchondral bone plate of the equine metacarpophalangeal joint. A comparison of Optical Coherence Tomography, Micro CT, and SEM techniques was performed. These data are compared between sites on a healthy sample and at points on an osteoarthritically degenerated sample. No significant correlation was found between the optical scattering coefficient and the micro-CT derived BMD for comparisons between different sites on the bone surface. Also OCT demonstrated a larger regional variation in scattering coefficient than did micro CT for bone mineral density. This suggests that the optical scattering coefficient of bone is not related solely to the volume-density of calcium-phosphate. Patches of lower optical scattering coefficient were found in the bone structure that was related to the osteoarthritic lesion area on the overlying cartilage. Areas of microcracking, as revealed by both SEM and micro CT produced distinctive granularity in the OCT images. In further experiments, OCT was compared with micro CT and mechanical strength testing (3-point bending) in a small animal model of cardiovascular disease (cholesterol overload in mice). In the cardiovascular diseased mice, micro-CT of the trabecular bone did not demonstrate a significant change in trabecular bone mineral density before and after administration of the high cholesterol diet. However mechanical testing demonstrated a decrease in mechanical strength and OCT demonstrated a corresponding statistically significant decrease in optical scattering of the bone.

  4. Percutaneous Bone Biopsies: Comparison between Flat-Panel Cone-Beam CT and CT-Scan Guidance

    SciTech Connect

    Tselikas, Lambros Joskin, Julien; Roquet, Florian; Farouil, Geoffroy; Dreuil, Serge; Hakimé, Antoine Teriitehau, Christophe; Auperin, Anne; Baere, Thierry de Deschamps, Frederic

    2015-02-15

    PurposeThis study was designed to compare the accuracy of targeting and the radiation dose of bone biopsies performed either under fluoroscopic guidance using a cone-beam CT with real-time 3D image fusion software (FP-CBCT-guidance) or under conventional computed tomography guidance (CT-guidance).MethodsSixty-eight consecutive patients with a bone lesion were prospectively included. The bone biopsies were scheduled under FP-CBCT-guidance or under CT-guidance according to operating room availability. Thirty-four patients underwent a bone biopsy under FP-CBCT and 34 under CT-guidance. We prospectively compared the two guidance modalities for their technical success, accuracy, puncture time, and pathological success rate. Patient and physician radiation doses also were compared.ResultsAll biopsies were technically successful, with both guidance modalities. Accuracy was significantly better using FP-CBCT-guidance (3 and 5 mm respectively: p = 0.003). There was no significant difference in puncture time (32 and 31 min respectively, p = 0.51) nor in pathological results (88 and 88 % of pathological success respectively, p = 1). Patient radiation doses were significantly lower with FP-CBCT (45 vs. 136 mSv, p < 0.0001). The percentage of operators who received a dose higher than 0.001 mSv (dosimeter detection dose threshold) was lower with FP-CBCT than CT-guidance (27 vs. 59 %, p = 0.01).ConclusionsFP-CBCT-guidance for bone biopsy is accurate and reduces patient and operator radiation doses compared with CT-guidance.

  5. Comparison of ring artifact correction methods for flat-detector CT.

    PubMed

    Prell, Daniel; Kyriakou, Yiannis; Kalender, Willi A

    2009-06-21

    In flat-detector CT, imperfect or defect detector elements may cause concentric ring artifacts due to their continuous over- or underestimation of attenuation values, which often disturb image quality. Especially due to the demand for high-spatial resolution images and the necessary pixel read-out without arbitrary pixel-binning, ring artifacts become more pronounced and the reduction of these artifacts becomes a necessity. We here present a comparison of two dedicated ring artifact correction methods for flat-detector CT, on the basis of different median and mean filterings of the reconstructed image but each working in different geometric planes. While the first method works in Cartesian coordinates, the second method performs a transformation to polar coordinates. Both post-processing methods efficiently reduce ring artifacts in the reconstructed images and improve image quality. The transformation to polar coordinates turned out to be a necessary step for efficient ring artifact correction, since correction in Cartesian coordinates suffers from newly introduced artifacts as well as insufficient correction of artifacts close to the center of rotation. PMID:19491452

  6. Comparison of ring artifact correction methods for flat-detector CT

    NASA Astrophysics Data System (ADS)

    Prell, Daniel; Kyriakou, Yiannis; Kalender, Willi A.

    2009-06-01

    In flat-detector CT, imperfect or defect detector elements may cause concentric ring artifacts due to their continuous over- or underestimation of attenuation values, which often disturb image quality. Especially due to the demand for high-spatial resolution images and the necessary pixel read-out without arbitrary pixel-binning, ring artifacts become more pronounced and the reduction of these artifacts becomes a necessity. We here present a comparison of two dedicated ring artifact correction methods for flat-detector CT, on the basis of different median and mean filterings of the reconstructed image but each working in different geometric planes. While the first method works in Cartesian coordinates, the second method performs a transformation to polar coordinates. Both post-processing methods efficiently reduce ring artifacts in the reconstructed images and improve image quality. The transformation to polar coordinates turned out to be a necessary step for efficient ring artifact correction, since correction in Cartesian coordinates suffers from newly introduced artifacts as well as insufficient correction of artifacts close to the center of rotation.

  7. Comparison of near-infrared spectroscopy with CT cerebral blood flow measurements in newborn piglets

    NASA Astrophysics Data System (ADS)

    Brown, Derek W.; Picot, Paul A.; Springett, Roger; Delpy, David T.; Lee, Ting-Yim

    2001-05-01

    Severely premature infants are often at high risk of cerebral hemorrhage or ischemic injury due to their inability to properly regulate blood flow to the brain. If blood flow is too high, the infant is at risk of cerebral hemorrhage, while too little blood flow can result in ischemic injury. The purpose of this research is to design and develop a means of non-invasively measuring cerebral blood flow (CBF) with near infrared spectroscopy (NIRS). Such a device would greatly aid the diagnosis and monitoring of afflicted infants. Previous attempts to measure CBF with NIRS have achieved limited success. In this study we acquired high signal-to-noise NIR spectrum from 600 to 980 nm with a cooled CCD spectrometer. This spectrometer enables the differential path length factor (DPF) to be estimated with accuracy using a second derivative technique described by Matcher et al. The validity of our new approach is determined via direct comparison with a previously validated computed tomography (CT) method. Three newborn piglets were studied. CBF measurements were performed at various partial arterial CO2 tensions (PaCO2) using both the NIRS and CT methods. The results of the two methods correlate well with a relationship of CBFCT equals -4.30 + 1.05 CBFNIRS (r2 equals 0.96).

  8. Spectral CT in the Demonstration of the Pancreatic Arteries and Their Branches: A Comparison With Conventional CT

    PubMed Central

    Shi, Yan-Jie; Zhang, Xiao-Peng; Sun, Ying-Shi; Qi, Li-Ping; Li, Ying; Zhu, Hai-Bin; Li, Xiao-Ting; Zhang, Xiao-Yan

    2016-01-01

    Abstract The aim of this study was to investigate the performance of monochromatic images of spectral computed tomographic (CT) in the visualization of the pancreatic arteries compared with polychromatic CT images. We conducted a case–control study in a group of 26 consecutive patients with monochromatic CT and contrasted the results against a control group of 26 consecutive patients with polychromatic CT. The CNR (contrast-to-noise ratio), SIR (signal intensity ratio), SNR (signal to noise ratio), and image noise were measured. A 5-score classification system was used to evaluate the branch order of pancreatic arteries. The course of pancreatic arteries was compared. Compared with polychromatic images, the CNR, SIR, and SNR obtained by monochromatic images were increased by 64.74%, 23.99%, and 39.50%. Branch visualization of PSPDA (posterior superior pancreaticoduodenal artery), ASPDA (anterior superior pancreaticoduodenal artery), and DPA (dorsal pancreatic artery) was better at monochromatic images than at polychromatic images. The display rate was significantly better in monochromatic images for the second and third segments of PSPDA, total course of ASPDA, and artery of uncinate process. Compared with polychromatic images, monochromatic images can improve the visualization of pancreatic arteries. PMID:26886636

  9. Quantitative comparison of noise texture across CT scanners from different manufacturers

    SciTech Connect

    Solomon, Justin B.; Christianson, Olav; Samei, Ehsan

    2012-10-15

    Purpose: To quantitatively compare noise texture across computed tomography (CT) scanners from different manufacturers using the noise power spectrum (NPS). Methods: The American College of Radiology CT accreditation phantom (Gammex 464, Gammex, Inc., Middleton, WI) was imaged on two scanners: Discovery CT 750HD (GE Healthcare, Waukesha, WI), and SOMATOM Definition Flash (Siemens Healthcare, Germany), using a consistent acquisition protocol (120 kVp, 0.625/0.6 mm slice thickness, 250 mAs, and 22 cm field of view). Images were reconstructed using filtered backprojection and a wide selection of reconstruction kernels. For each image set, the 2D NPS were estimated from the uniform section of the phantom. The 2D spectra were normalized by their integral value, radially averaged, and filtered by the human visual response function. A systematic kernel-by-kernel comparison across manufacturers was performed by computing the root mean square difference (RMSD) and the peak frequency difference (PFD) between the NPS from different kernels. GE and Siemens kernels were compared and kernel pairs that minimized the RMSD and |PFD| were identified. Results: The RMSD (|PFD|) values between the NPS of GE and Siemens kernels varied from 0.01 mm{sup 2} (0.002 mm{sup -1}) to 0.29 mm{sup 2} (0.74 mm{sup -1}). The GE kernels 'Soft,''Standard,''Chest,' and 'Lung' closely matched the Siemens kernels 'B35f,''B43f,''B41f,' and 'B80f' (RMSD < 0.05 mm{sup 2}, |PFD| < 0.02 mm{sup -1}, respectively). The GE 'Bone,''Bone+,' and 'Edge' kernels all matched most closely with Siemens 'B75f' kernel but with sizeable RMSD and |PFD| values up to 0.18 mm{sup 2} and 0.41 mm{sup -1}, respectively. These sizeable RMSD and |PFD| values corresponded to visually perceivable differences in the noise texture of the images. Conclusions: It is possible to use the NPS to quantitatively compare noise texture across CT systems. The degree to which similar texture across scanners could be achieved varies and is

  10. Comparison of CT-Number and Gray Scale Value of Different Dental Materials and Hard Tissues in CT and CBCT

    PubMed Central

    Emadi, Naghmeh; Safi, Yaser; Akbarzadeh Bagheban, Alireza; Asgary, Saeed

    2014-01-01

    Introduction: Computed tomography (CT) and cone-beam CT (CBCT) are valuable diagnostic aids for many clinical applications. This study was designed to compare the gray scale value (GSV) and Hounsfield unit (HU) of selected dental materials and various hard tissues using CT or CBCT. Methods and Materials: Three samples of all test materials including amalgam (AM), composite resin (CR), glass ionomer (GI), zinc-oxide eugenol (ZOE), calcium-enriched mixture (CEM) cement, AH-26 root canal sealer (AH-26), gutta-percha (GP), Coltosol (Col), Dycal (DL), mineral trioxide aggregate (MTA), zinc phosphate (ZP), and polycarbonate cement (PC) were prepared and scanned together with samples of bone, dentin and enamel using two CBCT devices, Scanora 3D (S3D) and NewTom VGi (NTV) and a spiral CT (SCT) scanner (Somatom Emotion 16 multislice spiral CT);. Subsequently, the HU and GSV values were determined and evaluated. The data were analyzed by the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was determined at 0.05. Results: There were significant differences among the three different scanners (P<0.05). The differences between HU/GSV values of 12 selected dental materials using NTV was significant (P<0.05) and for S3D and SCT was insignificant (P>0.05). All tested materials showed maximum values in S3D and SCT (3094 and 3071, respectively); however, bone and dentin showed low/medium values (P<0.05). In contrast, the tested materials and tissues showed a range of values in NTV (366 to15383; P<0.05). Conclusion: Scanner system can influence the obtained HU/GSV of dental materials. NTV can discriminate various dental materials, in contrast to S3D/SCT scanners. NTV may be a more useful diagnostic aid for clinical practice. PMID:25386210

  11. Comparison of ring artifact removal methods using flat panel detector based CT images

    PubMed Central

    2011-01-01

    Background Ring artifacts are the concentric rings superimposed on the tomographic images often caused by the defective and insufficient calibrated detector elements as well as by the damaged scintillator crystals of the flat panel detector. It may be also generated by objects attenuating X-rays very differently in different projection direction. Ring artifact reduction techniques so far reported in the literature can be broadly classified into two groups. One category of the approaches is based on the sinogram processing also known as the pre-processing techniques and the other category of techniques perform processing on the 2-D reconstructed images, recognized as the post-processing techniques in the literature. The strength and weakness of these categories of approaches are yet to be explored from a common platform. Method In this paper, a comparative study of the two categories of ring artifact reduction techniques basically designed for the multi-slice CT instruments is presented from a common platform. For comparison, two representative algorithms from each of the two categories are selected from the published literature. A very recently reported state-of-the-art sinogram domain ring artifact correction method that classifies the ring artifacts according to their strength and then corrects the artifacts using class adaptive correction schemes is also included in this comparative study. The first sinogram domain correction method uses a wavelet based technique to detect the corrupted pixels and then using a simple linear interpolation technique estimates the responses of the bad pixels. The second sinogram based correction method performs all the filtering operations in the transform domain, i.e., in the wavelet and Fourier domain. On the other hand, the two post-processing based correction techniques actually operate on the polar transform domain of the reconstructed CT images. The first method extracts the ring artifact template vector using a homogeneity

  12. Unusual Presentation of Bladder Paraganglioma: Comparison of 131I MIBG SPECT/CT and 68Ga DOTANOC PET/CT

    PubMed Central

    Jain, Tarun Kumar; Basher, Rajender Kumar; Gupta, Nitin; Shukla, Jaya; Singh, Shrawan Kumar; Mittal, Bhagwant Rai

    2016-01-01

    Extraadrenal chromaffin cell-related tumors or paragangliomas are rare, especially in the bladder, accounting for less than 1% of cases. We report a 16-year-old boy who presented with hematuria and paroxysmal headache and was found to have a prostatic growth infiltrating the urinary bladder on anatomical imaging. Iodine-131 (131I) metaiodobenzylguanidine (MIBG) whole-body scanning and subsequently gallium-68 (68Ga) DOTANOC positron emission tomography/computed tomography (PET/CT) were performed. The MIBG scan revealed a non-tracer-avid soft-tissue mass, while DOTANOC PET/CT revealed a tracer-avid primary soft-tissue mass involving the urinary bladder and prostate with metastasis to the iliac lymph nodes. He underwent surgical management; histopathology of the surgical specimen revealed a bladder paraganglioma, whereas the prostate was found to be free of tumor. PMID:26912984

  13. Personalized estimates of radiation dose from dedicated breast CT in a diagnostic population and comparison with diagnostic mammography

    NASA Astrophysics Data System (ADS)

    Vedantham, Srinivasan; Shi, Linxi; Karellas, Andrew; O'Connell, Avice M.; Conover, David L.

    2013-11-01

    This study retrospectively analyzed the mean glandular dose (MGD) to 133 breasts from 132 subjects, all women, who participated in a clinical trial evaluating dedicated breast CT in a diagnostic population. The clinical trial was conducted in adherence to a protocol approved by institutional review boards and the study participants provided written informed consent. Individual estimates of MGD to each breast from dedicated breast CT was obtained by combining x-ray beam characteristics with estimates of breast dimensions and fibroglandular fraction from volumetric breast CT images, and using normalized glandular dose coefficients. For each study participant and for the breast corresponding to that imaged with breast CT, an estimate of the MGD from diagnostic mammography (including supplemental views) was obtained from the DICOM image headers for comparison. This estimate uses normalized glandular dose coefficients corresponding to a breast with 50% fibroglandular weight fraction. The median fibroglandular weight fraction for the study cohort determined from volumetric breast CT images was 15%. Hence, the MGD from diagnostic mammography was corrected to be representative of the study cohort. Individualized estimates of MGD from breast CT ranged from 5.7 to 27.8 mGy. Corresponding to the breasts imaged with breast CT, the MGD from diagnostic mammography ranged from 2.6 to 31.6 mGy. The mean (± inter-breast SD) and the median MGD (mGy) from dedicated breast CT exam were 13.9 ± 4.6 and 12.6, respectively. For the corresponding breasts, the mean (± inter-breast SD) and the median MGD (mGy) from diagnostic mammography were 12.4 ± 6.3 and 11.1, respectively. Statistical analysis indicated that at the 0.05 level, the distributions of MGD from dedicated breast CT and diagnostic mammography were significantly different (Wilcoxon signed ranks test, p = 0.007). While the interquartile range and the range (maximum-minimum) of MGD from dedicated breast CT was lower than

  14. Rowing competitions and perspective

    NASA Astrophysics Data System (ADS)

    Flores, Alfinio; Bernhardt, Stephen A.; Shipman, Henry L.

    2015-02-01

    This paper is about integrating the use of graphing technology (specifically, GeoGebra) with principles of motion, principles of perspective, and the concept of vanishing points to model a dynamic event. Students were asked to analyse video images of a rowing competition filmed with a single camera positioned perpendicular to the race. The fixed position of the camera in such races makes it difficult to determine whether a scull closer to the camera is actually overtaking another, more distant scull. The paper illustrates how students in their first year at the university can integrate the use of technology, science, mathematics, and writing to solve a real world problem involving motion.

  15. CT cardiac imaging: evolution from 2D to 3D backprojection

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Pan, Tinsu; Sasaki, Kosuke

    2004-04-01

    The state-of-the-art multiple detector-row CT, which usually employs fan beam reconstruction algorithms by approximating a cone beam geometry into a fan beam geometry, has been well recognized as an important modality for cardiac imaging. At present, the multiple detector-row CT is evolving into volumetric CT, in which cone beam reconstruction algorithms are needed to combat cone beam artifacts caused by large cone angle. An ECG-gated cardiac cone beam reconstruction algorithm based upon the so-called semi-CB geometry is implemented in this study. To get the highest temporal resolution, only the projection data corresponding to 180° plus the cone angle are row-wise rebinned into the semi-CB geometry for three-dimensional reconstruction. Data extrapolation is utilized to extend the z-coverage of the ECG-gated cardiac cone beam reconstruction algorithm approaching the edge of a CT detector. A helical body phantom is used to evaluate the ECG-gated cone beam reconstruction algorithm"s z-coverage and capability of suppressing cone beam artifacts. Furthermore, two sets of cardiac data scanned by a multiple detector-row CT scanner at 16 x 1.25 (mm) and normalized pitch 0.275 and 0.3 respectively are used to evaluate the ECG-gated CB reconstruction algorithm"s imaging performance. As a reference, the images reconstructed by a fan beam reconstruction algorithm for multiple detector-row CT are also presented. The qualitative evaluation shows that, the ECG-gated cone beam reconstruction algorithm outperforms its fan beam counterpart from the perspective of cone beam artifact suppression and z-coverage while the temporal resolution is well maintained. Consequently, the scan speed can be increased to reduce the contrast agent amount and injection time, improve the patient comfort and x-ray dose efficiency. Based up on the comparison, it is believed that, with the transition of multiple detector-row CT into volumetric CT, ECG-gated cone beam reconstruction algorithms will

  16. A comparison of material decomposition techniques for dual-energy CT colonography

    NASA Astrophysics Data System (ADS)

    Nasirudin, Radin A.; Tachibana, Rie; Näppi, Janne J.; Mei, Kai; Kopp, Felix K.; Rummeny, Ernst J.; Yoshida, Hiroyuki; Noël, Peter B.

    2015-03-01

    In recent years, dual-energy computed tomography (DECT) has been widely used in the clinical routine due to improved diagnostics capability from additional spectral information. One promising application for DECT is CT colonography (CTC) in combination with computer-aided diagnosis (CAD) for detection of lesions and polyps. While CAD has demonstrated in the past that it is able to detect small polyps, its performance is highly dependent on the quality of the input data. The presence of artifacts such as beam-hardening and noise in ultra-low-dose CTC may severely degrade detection performances of small polyps. In this work, we investigate and compare virtual monochromatic images, generated by image-based decomposition and projection-based decomposition, with respect to CAD performance. In the image-based method, reconstructed images are firstly decomposed into water and iodine before the virtual monochromatic images are calculated. On the contrary, in the projection-based method, the projection data are first decomposed before calculation of virtual monochromatic projection and reconstruction. Both material decomposition methods are evaluated with regards to the accuracy of iodine detection. Further, the performance of the virtual monochromatic images is qualitatively and quantitatively assessed. Preliminary results show that the projection-based method does not only have a more accurate detection of iodine, but also delivers virtual monochromatic images with reduced beam hardening artifacts in comparison with the image-based method. With regards to the CAD performance, the projection-based method yields an improved detection performance of polyps in comparison with that of the image-based method.

  17. Comparison of bone histomorphometry and μCT for evaluating bone quality in tail-suspended rats

    NASA Astrophysics Data System (ADS)

    Sun, Lian-Wen; Huang, Yun-Fei; Wang, Ying; Luan, Hui-Qin; Fan, Yu-Bo

    2014-10-01

    Astronauts often suffer from microgravity-induced osteoporosis due to their time in space. Bone histomorphometry, the 'gold standard' technique for detecting bone quality, is widely used in the evaluation of osteoporosis. This study investigates whether μCT has the same application value as histomorphometry in the evaluation of weightlessness-induced bone loss. A total of 24 SD rats were distributed into three groups (n = 8, each): tail-suspension (TS), TS plus active exercise (TSA), and control (CON). After 21 days, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and μCT, and microstructure was measured by μCT and histomorphometry. BMD was found to have decreased significantly in TS and TSA compared with the CON group. The results of the μCT measurements showed that a change in BMD mainly occurred in the trabecular bone, and the trabecular BMD increased significantly in the TSA compared with the TS group. The comparison of μCT and histomorphometry showed that TS led to a significant decrease in bone volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N), and it led to an increase in trabecular separation (Tb.Sp). However, active exercise can prevent these changes. Significant differences in most parameters between TSA and CON were found by μCT but not by histomorphometry. Additionally, the parameters of these two methods are highly correlated. Therefore, the application value of μCT is as good as histomorphometry and DXA in the diagnosis of weightlessness-induced osteoporosis and is even better in evaluating the efficacy of exercise.

  18. Comparison and evaluation of methods for liver segmentation from CT datasets.

    PubMed

    Heimann, Tobias; van Ginneken, Bram; Styner, Martin A; Arzhaeva, Yulia; Aurich, Volker; Bauer, Christian; Beck, Andreas; Becker, Christoph; Beichel, Reinhard; Bekes, György; Bello, Fernando; Binnig, Gerd; Bischof, Horst; Bornik, Alexander; Cashman, Peter M M; Chi, Ying; Cordova, Andrés; Dawant, Benoit M; Fidrich, Márta; Furst, Jacob D; Furukawa, Daisuke; Grenacher, Lars; Hornegger, Joachim; Kainmüller, Dagmar; Kitney, Richard I; Kobatake, Hidefumi; Lamecker, Hans; Lange, Thomas; Lee, Jeongjin; Lennon, Brian; Li, Rui; Li, Senhu; Meinzer, Hans-Peter; Nemeth, Gábor; Raicu, Daniela S; Rau, Anne-Mareike; van Rikxoort, Eva M; Rousson, Mikaël; Rusko, László; Saddi, Kinda A; Schmidt, Günter; Seghers, Dieter; Shimizu, Akinobu; Slagmolen, Pieter; Sorantin, Erich; Soza, Grzegorz; Susomboon, Ruchaneewan; Waite, Jonathan M; Wimmer, Andreas; Wolf, Ivo

    2009-08-01

    This paper presents a comparison study between 10 automatic and six interactive methods for liver segmentation from contrast-enhanced CT images. It is based on results from the "MICCAI 2007 Grand Challenge" workshop, where 16 teams evaluated their algorithms on a common database. A collection of 20 clinical images with reference segmentations was provided to train and tune algorithms in advance. Participants were also allowed to use additional proprietary training data for that purpose. All teams then had to apply their methods to 10 test datasets and submit the obtained results. Employed algorithms include statistical shape models, atlas registration, level-sets, graph-cuts and rule-based systems. All results were compared to reference segmentations five error measures that highlight different aspects of segmentation accuracy. All measures were combined according to a specific scoring system relating the obtained values to human expert variability. In general, interactive methods reached higher average scores than automatic approaches and featured a better consistency of segmentation quality. However, the best automatic methods (mainly based on statistical shape models with some additional free deformation) could compete well on the majority of test images. The study provides an insight in performance of different segmentation approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques. PMID:19211338

  19. Wide row spacing in Louisiana sugarcane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is growing interest in the Louisiana sugarcane industry for a wider 8 foot row spacing than the conventional 6 foot row spacing. The wide row provides room for two drills of cane about 30 inches apart on each row. This type of wide row spacing lowers acre-feet from 7260 to 5445, thus reducing ...

  20. Comparison of spectral CT imaging methods based a photon-counting detector: Experimental study

    NASA Astrophysics Data System (ADS)

    Lee, Youngjin; Lee, Seungwan; Kim, Hee-Joung

    2016-04-01

    Photon-counting detectors allow spectral computed tomography (CT) imaging using energy-resolved information from a polychromatic X-ray spectrum. The spectral CT images based on the photon-counting detectors are dependent on the energy ranges defined by energy bins for image acquisition. In this study, K-edge and energy weighting imaging methods were experimentally implemented by using a spectral CT system with a cadmium zinc telluride (CZT)-based photon-counting detector. The spectral CT images were obtained by various energy bins and compared in terms of CNR improvement for investigating the effect of energy bins and the efficiency of the spectral CT imaging methods. The results showed that the spectral CT image quality was improved by using the particular energy bins, which were optimized for each spectral CT imaging method and target material. The CNR improvement was different for the spectral CT imaging methods and target materials. It can be concluded that an appropriate selection of imaging method for each target material and the optimization of energy bin can maximize the quality of spectral CT images.

  1. Coronary Artery Stent Evaluation Using a Vascular Model at 64-Detector Row CT: Comparison between Prospective and Retrospective ECG-Gated Axial Scans

    PubMed Central

    Furui, Shigeru; Kuwahara, Sadatoshi; Mehta, Dhruv; Kaminaga, Tatsuro; Miyazawa, Akiyoshi; Ueno, Yasunari; Konno, Kumiko

    2009-01-01

    Objective We wanted to evaluate the performance of prospective electrocardiogram (ECG)-gated axial scans for assessing coronary stents as compared with retrospective ECG-gated helical scans. Materials and Methods As for a vascular model of the coronary artery, a tube of approximately 2.5-mm inner diameter was adopted and as for stents, three (Bx-Velocity, Express2, and Micro Driver) different kinds of stents were inserted into the tube. Both patent and stenotic models of coronary artery were made by instillating different attenuation (396 vs. 79 Hounsfield unit [HU]) of contrast medium within the tube in tube model. The models were scanned with two types of scan methods with a simulated ECG of 60 beats per minute and using display field of views (FOVs) of 9 and 18 cm. We evaluated the in-stent stenosis visually, and we measured the attenuation values and the diameter of the patent stent lumen. Results The visualization of the stent lumen of the vascular models was improved with using the prospective ECG-gated axial scans and a 9-cm FOV. The inner diameters of the vascular models were underestimated with mean measurement errors of -1.10 to -1.36 mm. The measurement errors were smaller with using the prospective ECG-gated axial scans (Bx-Velocity and Express2, p < 0.0001; Micro Driver, p = 0.0004) and a 9-cm FOV (all stents: p < 0.0001), as compared with the other conditions, respectively. The luminal attenuation value was overestimated in each condition. For the luminal attenuation measurement, the use of prospective ECG-gated axial scans provided less measurement error compared with the retrospective ECG-gated helical scans (all stents: p < 0.0001), and the use of a 9-cm FOV tended to decrease the measurement error. Conclusion The visualization of coronary stents is improved by the use of prospective ECG-gated axial scans and using a small FOV with reduced blooming artifacts and increased spatial resolution. PMID:19412509

  2. The Demise of Skid Row.

    ERIC Educational Resources Information Center

    Siegal, Harvey A.; Inciardi, James A.

    1982-01-01

    Describes the history and evolution of the American skid row; analyzes the changes it has undergone, particularly in the face of urban renewal; and speculates on its future. Includes opinions of the inhabitants of skid row which were obtained from interviews. (MJL)

  3. In Vivo Comparison of Radiation Exposure of Dual-Energy CT Versus Low-Dose CT Versus Standard CT for Imaging Urinary Calculi

    PubMed Central

    Jepperson, Maria A.; Cernigliaro, Joseph G.; Ibrahim, El-Sayed H.; Morin, Richard L.; Haley, William E.

    2015-01-01

    Abstract Purpose: Dual-energy computed tomography (DECT) is an emerging imaging modality with the unique capability of determining urinary stone composition. This study compares radiation exposure of DECT, standard single-energy CT (SECT), and low-dose renal stone protocol single-energy CT (LDSECT) for the evaluation of nephrolithiasis in a single in vivo patient cohort. Materials and Methods: Following institutional review board (IRB) approval, we retrospectively reviewed 200 consecutive DECT examinations performed on patients with suspected urolithiasis over a 6-month period. Of these, 35 patients had undergone examination with our LDSECT protocol, and 30 patients had undergone examination of the abdomen and pelvis with our SECT imaging protocol within 2 years of the DECT examination. The CT dose index volume (CTDIvol) was used to compare radiation exposure between scans. Image quality was objectively evaluated by comparing image noise. Statistical evaluation was performed using a Student's t-test. Results: DECT performed at 80/140 kVp and 100/140 kVp did not produce a significant difference in radiation exposure compared with LDSECT (p=0.09 and 0.18, respectively). DECT performed at 80/140 kVp and 100/140 kVp produced an average 40% and 31%, respectively, reduction in radiation exposure compared with SECT (p<0.001). For patients imaged with the 100/140 kVp protocol, average values for images noise were higher in the LDSECT images compared with DECT images (p<0.001) and there was no significant difference in image noise between DECT and SECT images in the same patient (p=0.88). Patients imaged with the 80/140 kVp protocol had equivocal image noise compared with LDSECT images (p=0.44), however, DECT images had greater noise compared with SECT images in the same patient (p<0.001). Of the 75 patients included in the study, stone material was available for 16; DECT analysis correctly predicted stone composition in 15/16 patients (93%). Conclusion: DECT

  4. Comparison of PET-CT and Conventional Imaging in Staging Pediatric Rhabdomyosarcoma

    PubMed Central

    Federico, Sara M.; Spunt, Sheri L.; Krasin, Matthew J.; Billups, Catherine A.; Wu, Jianrong; Shulkin, Barry; Mandell, Gerald; McCarville, M. Beth

    2014-01-01

    Purpose To compare PET-CT to conventional imaging (CI) in staging pediatric rhabdomyosarcoma (RMS). Subjects and Methods Thirty subjects with RMS, median age 7.3 years, underwent PET-CT before therapy. PET-CTs and CI were independently reviewed by two radiologists and two nuclear medicine physician to determine the presence of nodal, pulmonary, bone, bone marrow and other sites of metastasis. Accuracy, sensitivity and specificity of PET-CT for detecting metastases was compared to CI using biopsy and clinical follow-up as reference standards. Maximum standardized uptake values (SUVmax) of primary tumors, lymph nodes and pulmonary nodules were measured. Results Primary tumors had an average SUVmax of 7.2 (range, 2.5-19.2). Accuracy rates for 17 subjects with nodal disease were 95% for PET-CT and 49% for CI. PET-CT had 94% sensitivity and 100% specificity for nodal disease. Of 7 pulmonary nodules detected by CI, 3 were not identified by PET-CT, 2 were indeterminate by PET-CT, and 1 was malignant with a SUVmax (3.4) > twice that of benign nodules. Two subjects had bone disease; both were identified by PET-CT but only 1 by CI. Four subjects had bone marrow disease, 2 had positive PET-CTs but none had positive CI. Two subjects had soft tissue metastases detected by PET-CT but not CI. Conclusion PET-CT performed better than CI in identifying nodal, bone, bone marrow, and soft tissue disease in children with RMS. CI remains essential for detection of pulmonary nodules. We recommend PET-CT for routine staging of children with RMS. CI with Tc99m bone scan can be eliminated. PMID:23255260

  5. Size-based emphysema cluster analysis on low attenuation area in 3D volumetric CT: comparison with pulmonary functional test

    NASA Astrophysics Data System (ADS)

    Lee, Minho; Kim, Namkug; Lee, Sang Min; Seo, Joon Beom; Oh, Sang Young

    2015-03-01

    To quantify low attenuation area (LAA) of emphysematous regions according to cluster size in 3D volumetric CT data of chronic obstructive pulmonary disease (COPD) patients and to compare these indices with their pulmonary functional test (PFT). Sixty patients with COPD were scanned by a more than 16-multi detector row CT scanner (Siemens Sensation 16 and 64) within 0.75mm collimation. Based on these LAA masks, a length scale analysis to estimate each emphysema LAA's size was performed as follows. At first, Gaussian low pass filter from 30mm to 1mm kernel size with 1mm interval on the mask was performed from large to small size, iteratively. Centroid voxels resistant to the each filter were selected and dilated by the size of the kernel, which was regarded as the specific size emphysema mask. The slopes of area and number of size based LAA (slope of semi-log plot) were analyzed and compared with PFT. PFT parameters including DLco, FEV1, and FEV1/FVC were significantly (all p-value< 0.002) correlated with the slopes (r-values; -0.73, 0.54, 0.69, respectively) and EI (r-values; -0.84, -0.60, -0.68, respectively). In addition, the D independently contributed regression for FEV1 and FEV1/FVC (adjust R sq. of regression study: EI only, 0.70, 0.45; EI and D, 0.71, 0.51, respectively). By the size based LAA segmentation and analysis, we evaluated the Ds of area, number, and distribution of size based LAA, which would be independent factors for predictor of PFT parameters.

  6. Comparison of CT Fluoroscopy-Guided Manual and CT-Guided Robotic Positioning System for In Vivo Needle Placements in Swine Liver

    SciTech Connect

    Cornelis, F.; Takaki, H.; Laskhmanan, M.; Durack, J. C.; Erinjeri, J. P.; Getrajdman, G. I.; Maybody, M.; Sofocleous, C. T.; Solomon, S. B.; Srimathveeravalli, G.

    2015-10-15

    PurposeTo compare CT fluoroscopy-guided manual and CT-guided robotic positioning system (RPS)-assisted needle placement by experienced IR physicians to targets in swine liver.Materials and MethodsManual and RPS-assisted needle placement was performed by six experienced IR physicians to four 5 mm fiducial seeds placed in swine liver (n = 6). Placement performance was assessed for placement accuracy, procedure time, number of confirmatory scans, needle manipulations, and procedure radiation dose. Intra-modality difference in performance for each physician was assessed using paired t test. Inter-physician performance variation for each modality was analyzed using Kruskal–Wallis test.ResultsPaired comparison of manual and RPS-assisted placements to a target by the same physician indicated accuracy outcomes was not statistically different (manual: 4.53 mm; RPS: 4.66 mm; p = 0.41), but manual placement resulted in higher total radiation dose (manual: 1075.77 mGy/cm; RPS: 636.4 mGy/cm; p = 0.03), required more confirmation scans (manual: 6.6; RPS: 1.6; p < 0.0001) and needle manipulations (manual: 4.6; RPS: 0.4; p < 0.0001). Procedure time for RPS was longer than manual placement (manual: 6.12 min; RPS: 9.7 min; p = 0.0003). Comparison of inter-physician performance during manual placement indicated significant differences in the time taken to complete placements (p = 0.008) and number of repositions (p = 0.04) but not in other study measures (p > 0.05). Comparison of inter-physician performance during RPS-assisted placement suggested statistically significant differences in procedure time (p = 0.02) and not in other study measures (p > 0.05).ConclusionsCT-guided RPS-assisted needle placement reduced radiation dose, number of confirmatory scans, and needle manipulations when compared to manual needle placement by experienced IR physicians, with equivalent accuracy.

  7. Low grade coal worker's pneumoconiosis. Comparison of CT and chest radiography.

    PubMed

    Gevenois, P A; Pichot, E; Dargent, F; Dedeire, S; Vande Weyer, R; De Vuyst, P

    1994-07-01

    We compared CT with chest radiography (CR) in the assessment of low grade coal worker's pneumoconiosis (CWP) in a population of 83 subjects. All subjects had a high-voltage p.a. CR, graded according to the ILO classification between 0/0 and 1/1, a conventional CT (CCT) using contiguous 1-cm-thick sections on the entire thorax and a set of 10 high-resolution CT (HRCT) images. CR and CT were separately read by consensus by 2 teams of 2 trained readers. CR was coded 0/0 in 9 subjects; 0/1 in 31; 1/0 in 28; 1/1 in 15. Among these groups of patients, micronodules were detected by CT in respectively 2 (22%), 14 (45%), 17 (61%) and 10 (67%) patients. In all groups, micronodules were more often detected by CT when the opacities detected on CR were scored as rounded (p, q) than irregular (s, t). Among the patients graded 0/0 or 0/1, CT showed micronodules in 40%. By contrast, among the patients graded 1/0 or 1/1, CT did not show micronodules in 37%, but revealed in numerous patients that opacities detected on CR were related to bronchiectasis and/or emphysema only. Comparative analysis of HRCT and CCT showed that both techniques are complementary and proved the usefulness of CCT in the detection or confirmation of low profusion of micronodules. PMID:8011384

  8. Multimodal imaging of the human temporal bone: A comparison of CT and optical scanning techniques

    NASA Astrophysics Data System (ADS)

    Voie, Arne H.; Whiting, Bruce; Skinner, Margaret; Neely, J. Gail; Lee, Kenneth; Holden, Tim; Brunsden, Barry

    2003-10-01

    A collaborative effort between Washington University in St. Louis and Spencer Technologies in Seattle, WA has been undertaken to create a multimodal 3D reconstruction of the human cochlea and vestibular system. The goal of this project is to improve the accuracy of in vivo CT reconstructions of implanted cochleae, and to expand the knowledge of high-resolution anatomical detail provided by orthogonal-plane optical sectioning (OPFOS). At WUSL, computed tomography (CT) images of the cochlea are used to determine the position of cochlear implant electrodes relative to target auditory neurons. The cochlear implant position is determined using pre- and post-operative CT scans. The CT volumes are cross-registered to align the semicircular canals and internal auditory canal, which have a unique configuration in 3-D space. The head of a human body donor was scanned with a clinical CT device, after which the temporal bones were removed, fixed in formalin and trimmed prior to scanning with a laboratory Micro CT scanner. Following CT, the temporal bones were sent to the OPFOS Imaging Lab at Spencer Technologies for a further analysis. 3-D reconstructions of CT and OPFOS imaging modalities were compared, and results are presented. [Work supported by NIDCD Grants R44-03623-5 and R01-00581-13.

  9. A comparison of micro-CT and thin section analysis of Lateglacial glaciolacustrine varves from Glen Roy, Scotland

    NASA Astrophysics Data System (ADS)

    Bendle, Jacob M.; Palmer, Adrian P.; Carr, Simon J.

    2015-04-01

    Despite the prevalence of thin section analysis in studies of Quaternary sediments, there are limitations associated with the production of thin sections (sediment modification) and the inherently 2D view that a thin section affords. Non-destructive and rapid scanning technologies such as X-ray computed microtomography (μCT) enable material samples to be visualised and analysed in 3D. In a Quaternary context, however, such techniques are in their infancy. This paper assesses the optimum approach to μCT analysis of Quaternary sediments, applying the method on Lateglacial glaciolacustrine varves from Glen Roy, Scotland. Scan datasets are examined at each stage of the thin section process and comparisons are made between 2D μCT images and thin sections for the recognition of 2D sediment features, with further appraisal of 3D models to identify 3D sediment structures. Comparable sediment features are observed in 2D μCT images and thin sections, however, the μCT imaging resolution determines the precision of microfacies descriptions. Additional 3D structures are distinguished from volumetric models that are otherwise impossible to identify in thin section slides. These 3D structures can locally alter sediment properties (e.g. layer thickness) as seen in 2D thin sections and/or digital images, although such variation cannot be detected with these media. It has been demonstrated that clear benefits exist in understanding the 3D structure of Quaternary sediments, both prior to thin-sectioning to avoid complicating (e.g. deformation) structures, and after thin-sectioning to establish the complex 3D context of 2D datasets. It is recommended that μCT and thin section techniques are applied in parallel in future studies, which will profit from the integration of 'true' 3D data. It is also advised that samples are scanned soon after field sampling, due to the significant modification of in situ sediment structures that can occur during thin section processing.

  10. Comparison of human and automatic segmentations of kidneys from CT images

    SciTech Connect

    Rao, Manjori; Stough, Joshua; Chi, Y.-Y.; Muller, Keith; Tracton, Gregg; Pizer, Stephen M.; Chaney, Edward L. . E-mail: chaney@med.unc.edu

    2005-03-01

    Purpose: A controlled observer study was conducted to compare a method for automatic image segmentation with conventional user-guided segmentation of right and left kidneys from planning computerized tomographic (CT) images. Methods and materials: Deformable shape models called m-reps were used to automatically segment right and left kidneys from 12 target CT images, and the results were compared with careful manual segmentations performed by two human experts. M-rep models were trained based on manual segmentations from a collection of images that did not include the targets. Segmentation using m-reps began with interactive initialization to position the kidney model over the target kidney in the image data. Fully automatic segmentation proceeded through two stages at successively smaller spatial scales. At the first stage, a global similarity transformation of the kidney model was computed to position the model closer to the target kidney. The similarity transformation was followed by large-scale deformations based on principal geodesic analysis (PGA). During the second stage, the medial atoms comprising the m-rep model were deformed one by one. This procedure was iterated until no changes were observed. The transformations and deformations at both stages were driven by optimizing an objective function with two terms. One term penalized the currently deformed m-rep by an amount proportional to its deviation from the mean m-rep derived from PGA of the training segmentations. The second term computed a model-to-image match term based on the goodness of match of the trained intensity template for the currently deformed m-rep with the corresponding intensity data in the target image. Human and m-rep segmentations were compared using quantitative metrics provided in a toolset called Valmet. Metrics reported in this article include (1) percent volume overlap; (2) mean surface distance between two segmentations; and (3) maximum surface separation (Hausdorff distance

  11. Hydrodynamic performance of multiple-row slotted breakwaters

    NASA Astrophysics Data System (ADS)

    Elbisy, Moussa S.; Mlybari, Ehab M.; Helal, Medhat M.

    2016-06-01

    This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes second-order waves. The numerical results obtained for limiting cases of double-row and triple-row walls are in good agreement with results of previous studies and experimental results. Comparisons with experimental measurements of the reflection, transmission, and dissipation coefficients ( C R , C T , and C E ) for double-row walls show that the proposed mathematical model adequately reproduces most of the important features. We found that for double-row walls, the C R increases with increasing wave number, kd, and with a decreasing permeable wall part, dm. The C T follows the opposite trend. The C E slowly increases with an increasing kd for lower kd values, reaches a maximum, and then decreases again. In addition, an increasing porosity of dm would significantly decrease the C R , while increasing the C T . At lower values of kd, a decreasing porosity increases the C E , but for high values of kd, a decreasing porosity reduces the C E . The numerical results indicate that, for triple-row walls, the effect of the arrangement of the chamber widths on hydrodynamic characteristics is not significant, except when kd<0.5. Double-row slotted breakwaters may exhibit a good wave-absorbing performance at kd>0.5, where by the horizontal wave force may be smaller than that of a single wall. On the other hand, the difference between double-row and triple-row vertical slotted breakwaters is marginal.

  12. Comparison of two respiration monitoring systems for 4D imaging with a Siemens CT using a new dynamic breathing phantom

    NASA Astrophysics Data System (ADS)

    Vásquez, A. C.; Runz, A.; Echner, G.; Sroka-Perez, G.; Karger, C. P.

    2012-05-01

    Four-dimensional computed tomography (4D-CT) requires breathing information from the patient, and for this, several systems are available. Testing of these systems, under realistic conditions, requires a phantom with a moving target and an expandable outer contour. An anthropomorphic phantom was developed to simulate patient breathing as well as lung tumor motion. Using the phantom, an optical camera system (GateCT) and a pressure sensor (AZ-733V) were simultaneously operated, and 4D-CTs were reconstructed with a Siemens CT using the provided local-amplitude-based sorting algorithm. The comparison of the tumor trajectories of both systems revealed discrepancies up to 9.7 mm. Breathing signal differences, such as baseline drift, temporal resolution and noise level were shown not to be the reason for this. Instead, the variability of the sampling interval and the accuracy of the sampling rate value written on the header of the GateCT-signal file were identified as the cause. Interpolation to regular sampling intervals and correction of the sampling rate to the actual value removed the observed discrepancies. Consistently, the introduction of sampling interval variability and inaccurate sampling rate values into the header of the AZ-733V file distorted the tumor trajectory for this system. These results underline the importance of testing new equipment thoroughly, especially if components of different manufacturers are combined.

  13. Segmental Comparison of Peripheral Arteries by Doppler Ultrasound and CT Angiography

    PubMed Central

    Swaminathan, Ram Kumar; Ganesan, Prakash; Mayavan, Manibharathi

    2016-01-01

    Introduction Diseases of peripheral arterial system are one of the common causes of limb pain, especially in elderly patients. Here we analyse non invasive imaging of peripheral arterial segments. Aim Aim of the study was to compare arterial diseases of extremities using Doppler ultrasound and CT angiography, and to find the better non-invasive modality of choice. Materials and Methods Fifty patients {14 patients with upper limb complaints (15 upper limbs) and 36 patients with lower limb complaints (72 lower limbs)} of peripheral arterial disease underwent Doppler ultrasound (USG) and CT Angiogram (CTA). Arterial systems divided into anatomic segments and luminal narrowing were compared using gray scale Doppler ultrasound and axial images of arterial phase of CT angiogram. Using statistical methods, sensitivity, specificity and accuracy of Doppler ultrasound and CT angiography were determined. Results Six hundred and nineteen arterial segments were studied with CT angiography and Doppler ultrasound. Of which 226 diseased segments were identified in CT angiography. Doppler overestimated narrowing by one grade in 47 segments, by two grade in 11 segments, by three grades in 30 segments and by four grades in 22 segments; underestimated by one grade in 28 segments, by two grades in 9 segments, by three grades in 5 segments and by four grades in 3 segments. Significant statistical difference exists between Doppler USG and CT angiography. Doppler showed good correlation with CT angiography in 74%, but, Doppler overestimated stenosis grade in a significant percentage. The sensitivity, specificity and accuracy of Doppler USG compared with CT angiography was 93.36%, 82.44%, and 86.42%. Conclusion Duplex Doppler can be the first investigation in excluding peripheral arterial disease, especially for evaluation of infra inguinal region of lower limbs and from second part of the subclavian artery in upper limbs. PMID:27042556

  14. Comparison of 4D-microSPECT and microCT for murine cardiac function

    PubMed Central

    Befera, Nicholas T.; Badea, Cristian T.; Johnson, G. Allan

    2014-01-01

    Purpose The objective of this study was to compare a new generation of four-dimensional (4D) microSPECT with microCT for quantitative in vivo assessment of murine cardiac function. Procedures 4D isotropic cardiac images were acquired from normal C57BL/6 mice with either microSPECT at 350-micron resolution (n=6) or microCT at 88-micron resolution (n=6). One additional mouse with myocardial infarction (MI) was scanned with both modalities. Prior to imaging, mice were injected with either 99mTc -tetrofosmin for microSPECT, or a liposomal blood pool contrast agent for microCT. Segmentation of the left ventricle (LV) was performed using Vitrea (Vital Images) software, to derive global and regional function. Results Measures of global LV function between microSPECT and microCT groups were comparable (e.g. ejection fraction=71±6%-microSPECT and 68±4%-microCT). Regional functional indices (wall motion, wall thickening, regional ejection fraction) were also similar for the two modalities. In the mouse with MI, microSPECT identified a large perfusion defect that was not evident with microCT. Conclusions Despite lower spatial resolution, microSPECT was comparable to microCT in the quantitative evaluation of cardiac function. MicroSPECT offers an advantage over microCT in the ability to evaluate myocardial perfusion radiotracer distribution and function simultaneously. MicroSPECT should be considered as an alternative to microCT and MR for preclinical cardiac imaging in the mouse. PMID:24037175

  15. Comparison of CT and MRI in Diagnosis of Laryngeal Carcinoma with Anterior Vocal Commissure Involvement

    PubMed Central

    Wu, Jian-hui; Zhao, Jing; Li, Zeng-hong; Yang, Wei-qiang; Liu, Qi-hong; Yang, Zhi-yun; Liao, Bing; Li, Xiao-ling; Wang, Bin; Qin, Hao; Luo, Jie; Lv, Ke-xing; Wen, Wei-ping; Lei, Wen-bin

    2016-01-01

    This study aimed to compare the accuracy of CT and MRI in determining the invasion of thyroid cartilage by and the T staging of laryngeal carcinoma with anterior vocal commissure (AVC) involvement. A total of 26 cases of laryngeal carcinomas with AVC involvement from May 2012 to January 2014 underwent enhanced CT and MRI scan, out of whom 6 patients also underwent diffusion-weighted magnetic resonance imaging(DWI). T staging and thyroid cartilage involvement were evaluated. All the surgical specimens underwent serial section and were reviewed by two senior pathologists independently. When compared with pathologic staging, the accuracy was 88.46% (23/26) of MRI scan (with a 95% confidence interval 37~77%) and 57.69% (15/26) of CT scan (with a 95% confidence interval 70~98%), respectively (P < 0.01). We also reported three cases who were misdiagnosed on CT or MRI about either the thyroid cartilage was involved or not, and one case of preliminary study of DWI. Compared to CT, MRI exhibited a higher accuracy rate on T staging of laryngeal carcinomas with AVC involvement. Combined utility of CT and MRI could help improve the accuracy of assessment of thyroid cartilage involvement and T staging of laryngeal carcinomas with AVC involvement. PMID:27480073

  16. Comparison of CT numbers of organs before and after plastination using standard S-10 technique.

    PubMed

    Shanthi, Pauline; Singh, Rabi Raja; Gibikote, Sridhar; Rabi, Suganthy

    2015-05-01

    Plastination is the art of preserving biological tissues with curable polymers. Imaging with plastinates offers a unique opportunity for radiographic, anatomical, pathological correlation to elucidate complex anatomical relationships. The aim of this study was to make plastinates from cadavers using the standard S-10 plastination technique and to compare the radiological properties of the tissue before and afterwards to examine the suitability of plastinates as phantoms for planning radiotherapy treatment. An above-diaphragm and a below-diaphragm specimen were obtained from a male and a female cadaver, respectively, and subjected to the standard S-10 plastination technique. CT images were obtained before and after plastination and were compared using Treatment Planning System for anatomical accuracy, volume of organs, and CT numbers. The plastinated specimens obtained were dry, robust, and durable. CT imaging of the plastinated specimens showed better anatomical detail of the organs than the preplastinate. Organ volumes were estimated by contouring the organs' outline in the CT images of the preplastinated and postplastinated specimens, revealing an average shrinkage of 25%. CT numbers were higher in the plastinated specimens except in bones and air-filled cavities such as the maxillary air sinus. Although plastination by the standard S-10 technique preserves anatomical accuracy, it increases the CT numbers of the organs because of the density of silicone, making it unsuitable for radiation dosimetry. Further improvements of the technique could yield more suitable plastinated phantoms. PMID:25708008

  17. Localized Prostate Cancer Detection with 18F FACBC PET/CT: Comparison with MR Imaging and Histopathologic Analysis

    PubMed Central

    Mena, Esther; Shih, Joanna; Pinto, Peter A.; Merino, Maria J.; Lindenberg, Maria L.; Bernardo, Marcelino; McKinney, Yolanda L.; Adler, Stephen; Owenius, Rikard; Choyke, Peter L.; Kurdziel, Karen A.

    2014-01-01

    Purpose To characterize uptake of 1-amino-3-fluorine 18-fluorocyclobutane-1-carboxylic acid (18F FACBC) in patients with localized prostate cancer, benign prostatic hyperplasia (BPH), and normal prostate tissue and to evaluate its potential utility in delineation of intraprostatic cancers in histopathologically confirmed localized prostate cancer in comparison with magnetic resonance (MR) imaging. Materials and Methods Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study. Twenty-one men underwent dynamic and static abdominopelvic 18F FACBC combined positron emission tomography (PET) and computed tomography (CT) and multiparametric (MP) 3-T endorectal MR imaging before robotic-assisted prostatectomy. PET/CT and MR images were coregistered by using pelvic bones as fiducial markers; this was followed by manual adjustments. Whole-mount histopathologic specimens were sliced with an MR-based patient-specific mold. 18F FACBC PET standardized uptake values (SUVs) were compared with those at MR imaging and histopathologic analysis for lesion- and sector-based (20 sectors per patient) analysis. Positive and negative predictive values for each modality were estimated by using generalized estimating equations with logit link function and working independence correlation structure. Results 18F FACBC tumor uptake was rapid but reversible. It peaked 3.6 minutes after injection and reached a relative plateau at 15–20 minutes (SUVmax[15–20min]). Mean prostate tumor SUVmax(15–20min) was significantly higher than that of the normal prostate (4.5 ± 0.5 vs 2.7 ± 0.5) (P < .001); however, it was not significantly different from that of BPH (4.3 ± 0.6) (P = .27). Sector-based comparison with histopathologic analysis, including all tumors, revealed sensitivity and specificity of 67% and 66%, respectively, for 18F FACBC PET/CT and 73% and 79%, respectively, for T2-weighted MR imaging. 18F FACBC PET/CT and MP MR

  18. Percutaneous Transthoracic Lung Biopsy: Comparison Between C-Arm Cone-Beam CT and Conventional CT Guidance

    PubMed Central

    Cheng, Yun-Chung; Tsai, Sheng-Heng; Cheng, Yuchi; Chen, Jeon-Hor; Chai, Jyh-Wen; Chen, Clayton Chi-Chang

    2015-01-01

    BACKGROUND: C-arm cone-beam computed tomography (CBCT) is a comparatively novel modality for guiding percutaneous transthoracic lung biopsies (PTLBs), and despite its potential advantages over conventional computed tomography (CCT), a head-to-head comparison of the two techniques has yet to be reported in the literature. This study aims to evaluate the diagnostic value and safety of CBCT-guided PTLB compared to CCT-guided biopsy, with cases performed in a single hospital. METHODS: A total of 104 PTLB patients were retrospectively analyzed in this study. 35 PTLBs were performed under CBCT guidance, and 69 PTLBs were performed under CCT guidance. Diagnostic accuracy, sensitivity, and specificity for malignancy as well as procedure time, radiation dose of patients, and complication rate in the two groups were compared. RESULTS: Total procedure time was significantly lower in the CBCT group (32 ± 11 minutes) compared to the CCT group (38 ± 9.7 minutes; P = .009), especially among patients ≥ 70 years of age (CBCT: 33 ± 12 minutes, CCT: 42 ± 13, P = .022). For lesions in the lower lobes, the CBCT-guided group received significantly reduced effective radiation dose (2.9 ± 1.6 mSv) than CCT-guided patients (3.7 ± 0.80; P = .042). Diagnostic accuracy, sensitivity, and specificity for malignancy were comparable between the two groups, as were post-biopsy complication rates. CONCLUSION: CBCT guidance significantly reduces the procedure time and radiation exposure for PTLBs compared with CCT, and should be considered in clinical settings that may be difficult or time-consuming to perform under CCT. PMID:26310371

  19. A Comparison of daily megavoltage CT and ultrasound image guided radiation therapy for prostate cancer

    SciTech Connect

    Peng Cheng; Kainz, Kristofer; Lawton, Colleen; Li, X. Allen

    2008-12-15

    In order to quantify the differences between ultrasound-imaging and megavoltage-CT (MVCT) daily prostate localization in prostate-cancer radiotherapy and their dosimetric impacts, daily shifts were analyzed for a total of 140 prostate cancer patients; 106 positioned using ultrasound-based imaging [B-mode Acquisition and Targeting (BAT)], and 34 using the MVCT from a TomoTherapy Hi-Art unit. The shifts indicated by the two systems were compared statistically along the right/left (R/L), superior/inferior (S/I), and anterior/posterior (A/P) directions. The systematic and random variations among the daily alignments were calculated. Margins to account for these shifts were estimated. The mean shifts and standard deviations along the R/L, S/I, and A/P directions were -0.11{+-}3.80, 0.67{+-}4.67, and 2.71{+-}6.31 mm for BAT localizations and -0.98{+-}5.13, 0.27{+-}3.35, and 1.00{+-}4.22 mm for MVCT localizations, respectively. The systematic and random variations in daily shifts based on MVCT were generally smaller than those based on BAT, especially along the A/P direction. A t-test showed this difference to be statistically significant. The planning target volume margins in the A/P direction estimated to account for daily variations were 8.81 and 14.66 mm based on MVCT and BAT data, respectively. There was no statistically significant difference in the daily prostate movement pattern between the first few fractions and the remaining fractions. Dosimetric comparison of MVCT and BAT prostate alignments was performed for seven fractions from a patient. The degradation from the plan caused by the MVCT alignment is trivial, while that by BAT is substantial. The MVCT technique results in smaller variations in daily shifts than ultrasound imaging, indicating that MVCT is more reliable and precise for prostate localization. Ultrasound-based localization may overestimate the daily prostate motion, particularly in the A/P direction, negatively impacting prostate dose coverage

  20. Louisiana farm discussion: 8 foot row spacing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This year several tests in growers’ fields were used to compare traditional 6-foot row spacing to 8-foot row spacing. Cane is double-drilled in the wider row spacing. The wider row spacing would accommodate John Deere 3522 harvester. Field data indicate the sugarcane yields are very comparable in 8-...

  1. Performance comparison between static and dynamic cardiac CT on perfusion quantitation and patient classification tasks

    NASA Astrophysics Data System (ADS)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2015-03-01

    Cardiac CT acquisitions for perfusion assessment can be performed in a dynamic or static mode. In this simulation study, we evaluate the relative classification and quantification performance of these modes for assessing myocardial blood flow (MBF). In the dynamic method, a series of low dose cardiac CT acquisitions yields data on contrast bolus dynamics over time; these data are fit with a model to give a quantitative MBF estimate. In the static method, a single CT acquisition is obtained, and the relative CT numbers in the myocardium are used to infer perfusion states. The static method does not directly yield a quantitative estimate of MBF, but these estimates can be roughly approximated by introducing assumed linear relationships between CT number and MBF, consistent with the ways such images are typically visually interpreted. Data obtained by either method may be used for a variety of clinical tasks, including 1) stratifying patients into differing categories of ischemia and 2) using the quantitative MBF estimate directly to evaluate ischemic disease severity. Through simulations, we evaluate the performance on each of these tasks. The dynamic method has very low bias in MBF estimates, making it particularly suitable for quantitative estimation. At matched radiation dose levels, ROC analysis demonstrated that the static method, with its high bias but generally lower variance, has superior performance in stratifying patients, especially for larger patients.

  2. Comparison of Preoperative Temporal Bone CT with Intraoperative Findings in Patients with Cholesteatoma

    PubMed Central

    Rogha, Mehrdad; Hashemi, Sayyed Mostafa; Mokhtarinejad, Farhad; Eshaghian, Afrooz; Dadgostar, Alireza

    2014-01-01

    Introduction: Cholesteatoma is traditionally diagnosed by otoscopic examination and treated by surgery. The necessity for imaging in an uncomplicated case is controversial. This study was planned to investigate the usefulness of a preoperative high-resolution computed tomography (HRCT) scan in depicting the status of middle ear structures in the presence of cholesteatoma and also to compare the correspondence between pre- and intraoperative CT findings in patients with cholesteatoma. Materials and Methods: This prospective descriptive study was performed from January 2009 to May 2011 in 36 patients with cholesteatoma who were referred to the Kashani and Al-Zahra Clinics of Otolaryngology. Preoperative high-resolution temporal bone CT scans (axial and coronal views) were carried out and compared with intraoperative findings. Results: Evaluation of 36 patients and their CT scans revealed excellent correlation for sigmoid plate erosion, widening of aditus, and erosion of scutum; good correlation for erosion of malleus and tegmen; moderate correlation for lateral canal fistula (LCF) and erosion of mastoid air cells; and poor correlation for facial nerve dehiscence (FND), incus, and stapes erosion. Conclusion: A preoperative CT scan may be helpful in relation to diagnosis and decision making for surgery in cases of cholesteatoma and ossicular erosion. The CT scan can accurately predict the extent of disease and is helpful for detection of lateral canal fistula, erosions of dural plate, and ossicular erosions. However it is not able to distinguish between cholesteatoma and mucosal disease, facial nerve dehiscency, incus, and stapes erosion. PMID:24505568

  3. Measurement of lateral acetabular coverage: a comparison between CT and plain radiography

    PubMed Central

    Chadayammuri, Vivek; Garabekyan, Tigran; Jesse, Mary-Kristen; Pascual-Garrido, Cecilia; Strickland, Colin; Milligan, Kenneth; Mei-Dan, Omer

    2015-01-01

    We prospectively evaluated the degree of absolute agreement between measurements of lateral center-edge angle (LCEA) on plain radiography (XR) and computed tomography (CT) in a consecutive cohort of 205 patients (410 hips) undergoing hip arthroscopy. Preoperative measurements of the LCEA were performed bilaterally utilizing standardized anteroposterior radiographs and coronal reformatted CT scans. Demographic variables including age, gender, height, weight, BMI and clinical diagnosis were recorded for all patients. Overall, measured values of the LCEA were 2.1° larger on CT compared with XR (32.9° versus 30.8°, P < 0.001). Subgroup analysis revealed the highest mean difference in hips with acetabular dysplasia and concomitant cam-type femoroacetabular impingement (FAI) [mean difference (CT–XR) 5.5°, 95% confidence interval (CI) 3.7°–7.3°, P = 0.011], followed by hips with isolated acetabular dysplasia (mean difference [CT–XR] 4.9°, 95% CI 2.7°–7.0°, P < 0.001). In contrast, 119 (29.0%) of the hips demonstrated larger measurements of the LCEA on 25 XR relative to CT. Of these hips, 20 (16.8%) had pincer-FAI and 25 had cam-FAI (21.0%), representing a significantly higher proportion compared with all other clinical subgroups (P = 0.045 and 0.036, respectively). Our study demonstrates measured values of the LCEA are consistently inflated on CT relative to XR for a wide variety of hip pathologies, highlighting the need for standardization and validation of CT-based measurements to improve the quality of clinical decision making. Level of Evidence: Diagnostic Level II. PMID:27011864

  4. Comparison of 18F-FDG PET/CT for Systemic Staging of Newly Diagnosed Invasive Lobular Carcinoma Versus Invasive Ductal Carcinoma

    PubMed Central

    Hogan, Molly P.; Goldman, Debra A.; Dashevsky, Brittany; Riedl, Christopher C.; Gönen, Mithat; Osborne, Joseph R.; Jochelson, Maxine; Hudis, Clifford; Morrow, Monica; Ulaner, Gary A.

    2016-01-01

    Although guidelines such as those of the National Comprehensive Cancer Network consider 18F-FDG PET/CT for systemic staging of newly diagnosed stage III breast cancer patients, factors in addition to stage may influence the utility of PET/CT. Because invasive lobular carcinoma (ILC) is less conspicuous than invasive ductal carcinoma (IDC) on 18F-FDG PET, we hypothesized that tumor histology may be one such factor. We evaluated PET/CT systemic staging of patients newly diagnosed with ILC compared with IDC. Methods In this Institutional Review Board–approved retrospective study, our Hospital Information System was screened for ILC patients who underwent PET/CT in 2006–2013 before systemic or radiation therapy. Initial stage was determined from examination, mammography, ultrasound, MR, or surgery. PET/CT was performed to identify unsuspected distant metastases. A sequential cohort of stage III IDC patients was evaluated for comparison. Upstaging rates were compared using the Pearson χ2 test. Results The study criteria were fulfilled by 146 ILC patients. PET/CT revealed unsuspected distant metastases in 12 (8%): 0 of 8 with initial stage I, 2 of 50 (4%) stage II, and 10 of 88 (11%) stage III. Upstaging to IV by PET/CT was confirmed by biopsy in all cases. Three of 12 upstaged patients were upstaged only by the CT component of the PET/CT, as the metastases were not 18F-FDG–avid. In the comparison stage III IDC cohort, 22% (20/89) of patients were upstaged to IV by PET/CT. All 20 demonstrated 18F-FDG–avid metastases. The relative risk of PET/CT revealing unsuspected distant metastases in stage III IDC patients was 1.98 times (95% confidence interval, 0.98–3.98) that of stage III ILC patients (P = 0.049). For 18F-FDG–avid metastases, the relative risk of PET/CT revealing unsuspected 18F-FDG–avid distant metastases in stage III IDC patients was 2.82 times (95% confidence interval, 1.26–6.34) that of stage III ILC patients (P = 0.007). Conclusion 18F

  5. Incidental Detection of a Hodgkin Lymphoma on 18F-Choline PET/CT and Comparison With 18F-FDG in a Patient With Prostate Cancer.

    PubMed

    Goineau, Aurore; Colombié, Mathilde; Rousseau, Caroline; Sadot-Lebouvier, Sophie; Supiot, Stéphane

    2015-08-01

    Combined PET/CT scanning with (18)F-FDG is in current use in Hodgkin lymphoma. New tracers have been developed, such as (18)F-choline in prostate cancer. Its use is under investigation in other solid tumors (eg, brain, liver, lung). We report a case of Hodgkin lymphoma incidentally detected on (18)F-choline PET/CT in a prostate cancer patient and show a comparison with (18)F-FDG PET/CT. (18)F-choline PET/CT detected more lymph node lesions than the (18)F-FDG PET/CT for this patient. Comparative studies of the 2 tracers might help fine-tune treatments and, in particular, delineate target zones in radiation therapy. PMID:26018683

  6. Comparison between echocardiographic and non-ECG-gated CT measurements in dogs.

    PubMed

    Laborda-Vidal, P; Maddox, T W; Navarro-Cubas, X; Dukes-McEwan, J; McConnell, J F

    2015-03-28

    The aim of this study was to compare echocardiographic measurements with non-ECG-gated contrast-enhanced cardiac CT measurements in dogs. Fifty-seven dogs were included in the study. The following echocardiographic parameters were measured: M-mode interventricular septum in diastole and systole, left ventricular internal diameter in diastole and systole, left ventricular free wall in diastole and systole, 2D left atrial maximal diameter, 2D left atrium to aorta ratio in diastole, 2D aortic annulus in systole and 2D pulmonary annulus in diastole and systole. CT measurements were obtained from multiplanar reconstruction images, replicating the imaging planes used for 2D measurements on echocardiography. It was not possible to discriminate between systole and diastole. The results showed moderate Lin's concordance correlation coefficients between the left ventricular internal diameter in systole (0.77), the aortic annuli (0.84) and the pulmonary annuli in diastole (0.78) and systole (0.80). Low coefficients were obtained between the other parameters. Bland-Altman plots for the parameters with highest concordance correlation coefficients were calculated. They suggested equivalence between the measurements of the aortic annuli. Equivalence was not seen between the remaining echocardiographic and CT measurements. Therefore, non-ECG-gated CT is not a reliable way of quantitatively assessing cardiac size. PMID:25694270

  7. Accuracy assessment of 3D bone reconstructions using CT: an intro comparison.

    PubMed

    Lalone, Emily A; Willing, Ryan T; Shannon, Hannah L; King, Graham J W; Johnson, James A

    2015-08-01

    Computed tomography provides high contrast imaging of the joint anatomy and is used routinely to reconstruct 3D models of the osseous and cartilage geometry (CT arthrography) for use in the design of orthopedic implants, for computer assisted surgeries and computational dynamic and structural analysis. The objective of this study was to assess the accuracy of bone and cartilage surface model reconstructions by comparing reconstructed geometries with bone digitizations obtained using an optical tracking system. Bone surface digitizations obtained in this study determined the ground truth measure for the underlying geometry. We evaluated the use of a commercially available reconstruction technique using clinical CT scanning protocols using the elbow joint as an example of a surface with complex geometry. To assess the accuracies of the reconstructed models (8 fresh frozen cadaveric specimens) against the ground truth bony digitization-as defined by this study-proximity mapping was used to calculate residual error. The overall mean error was less than 0.4 mm in the cortical region and 0.3 mm in the subchondral region of the bone. Similarly creating 3D cartilage surface models from CT scans using air contrast had a mean error of less than 0.3 mm. Results from this study indicate that clinical CT scanning protocols and commonly used and commercially available reconstruction algorithms can create models which accurately represent the true geometry. PMID:26037323

  8. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT.

    PubMed

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2014-04-01

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)(-1), cardiac output = 3, 5, 8 L min(-1)). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This

  9. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT

    NASA Astrophysics Data System (ADS)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2014-04-01

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)-1, cardiac output = 3, 5, 8 L min-1). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This suggests that

  10. Acceptance of Combined Coronary CT Angiography and Myocardial CT Perfusion versus Conventional Coronary Angiography in Patients with Coronary Stents—Intraindividual Comparison

    PubMed Central

    Martus, Peter; Laule, Michael; Dewey, Marc; Schönenberger, Eva

    2015-01-01

    Objectives To evaluate how well patients with coronary stents accept combined coronary computed tomography angiography (CTA) and myocardial CT perfusion (CTP) compared with conventional coronary angiography (CCA). Background While combined CTA and CTP may improve diagnostic accuracy compared with CTA alone, patient acceptance of CTA/CTP remains to be defined. Methods A total of 90 patients with coronary stents prospectively underwent CTA/CTP (both with contrast agent, CTP with adenosine) and CCA as part of the CARS-320 study. In this group, an intraindividual comparison of patient acceptance of CTA, CTP, and CCA was performed. Results CTP was experienced to be significantly more painful than CTA (p<0.001) and was associated with a higher frequency of dyspnea (p<0.001). Comparison of CTA/CTP with CCA revealed no significant differences in terms of pain (p = 0.141) and comfort (p = 0.377). Concern before CTA/CTP and CCA and overall satisfaction were likewise not significantly different (p = 0.097 and p = 0.123, respectively). Nevertheless, about two thirds (n = 60, 68%) preferred CTA/CTP to CCA (p<0.001). Moreover, patients felt less helpless during CTA/CTP than during CCA (p = 0.026). Lack of invasiveness and absence of pain were the most frequently mentioned advantages of CTA/CTP over CCA in our patient population. Conclusions CCA and combined CTA/CTP are equally well accepted by patients; however, more patients prefer CTA/CTP. CTP was associated with more intense pain than CTA and more frequently caused dyspnea than CTA alone. Trial Registration ClinicalTrials.gov NCT00967876 PMID:26327127

  11. Dose management in CT facility

    PubMed Central

    Tsapaki, V; Rehani, M

    2007-01-01

    Computed Tomography (CT) examinations have rapidly increased in number over the last few years due to recent advances such as the spiral, multidetector-row, CT fluoroscopy and Positron Emission Tomography (PET)-CT technology. This has resulted in a large increase in collective radiation dose as reported by many international organisations. It is also stated that frequently, image quality in CT exceeds the level required for confident diagnosis. This inevitably results in patient radiation doses that are higher than actually required, as also stressed by the US Food and Drug Administration (FDA) regarding the CT exposure of paediatric and small adult patients. However, the wide range in exposure parameters reported, as well as the different CT applications reveal the difficulty in standardising CT procedures. The purpose of this paper is to review the basic CT principles, outline the recent technological advances and their impact in patient radiation dose and finally suggest methods of radiation dose optimisation. PMID:21614279

  12. Comparison of 64-Detector CT Colonography and Conventional Colonoscopy in the Detection of Colorectal Lesions

    PubMed Central

    Devir, Cigdem; Kebapci, Mahmut; Temel, Tuncer; Ozakyol, Aysegul

    2016-01-01

    Background: Colon cancer is a leading cause of morbidity and mortality in developed countries. The early detection of colorectal cancer using screening programs is important for managing early-stage colorectal cancers and polyps. Modalities that allow examination of the entire colon are conventional colonoscopy, double contrast barium enema examination and multi-detector computed tomography (MDCT) colonography. Objectives: To compare CT colonography and conventional colonoscopy results and to evaluate the accuracy of CT colonography for detecting colorectal lesions. Patients and Methods: In a prospective study performed at Gastroenterology and Radiology Departments of Medical Faculty of Eskisehir Osmangazi University, CT colonography and colonoscopy results of 31 patients with family history of colorectal carcinoma, personal or family history of colorectal polyps, lower gastrointestinal tract bleeding, change in bowel habits, iron deficiency anemia and abdominal pain were compared. Regardless of the size, CT colonography and conventional colonoscopy findings for all the lesions were cross - tabulated and the sensitivity, specificity, and positive and negative predictive values were calculated. To assess the agreement between CT colonography and conventional colonoscopy examinations, the Kappa coefficient of agreementt was used. Statistical analysis was performed by SPSS ver 15.0. Results: Regardless of the size, MDCT colonography showed 83% sensitivity and 95% specificity, with a positive predictive value of 95% and a negative predictive value of 83% for the detection of colorectal polyps and masses. MDCT colonography displayed 92% sensitivity and 95% specificity, with a positive predictive value of 92% and a negative predictive value of 95% for polyps ≥ 10 mm. For polyps between 6mm and 9 mm, MDCT colonography displayed 75% sensitivity and 100% specificity, with a positive predictive value of 100% and a negative predictive value of 90%. For polyps ≤ 5 mm MDCT

  13. Diagnosis of acute acalculous cholecystitis: a comparison of sonography, scintigraphy, and CT

    SciTech Connect

    Mirvis, S.E.; Vainright, J.R.; Nelson, A.W.; Johnston, G.S.; Shorr, R.; Rodriguez, A.; Whitley, N.O.

    1986-12-01

    The clinical and laboratory diagnosis of acute acalculous cholecystitis is difficult, and the reliability of various diagnostic imaging techniques has not been established. The results of several imaging procedures performed over a 6-year period on 56 patients with clinically suspected acute acalculous cholecystitis were evaluated retrospectively. Sonography and CT were both highly sensitive (92% and 100%, respectively) and specific (96% and 100%, respectively). Hepatobiliary scintigraphy was compromised by frequent false-positives; the result was a specificity of only 38%. Percutaneous bile aspiration was insufficiently sensitive (33%) for diagnosis. Sonography was as sensitive as hepatobiliary scintigraphy and was more specific in establishing the diagnosis. Because sonography is relatively inexpensive and can be performed at the bedside, it should be regarded as a satisfactory screening procedure. However, CT is a good alternative in an easily transported patient when other intraabdominal disease is suspected.

  14. Comparison of DCE-CT models for quantitative evaluation of Ktrans in larynx tumors

    NASA Astrophysics Data System (ADS)

    Oosterbroek, J.; Bennink, E.; Philippens, M. E. P.; Raaijmakers, C. P. J.; Viergever, M. A.; de Jong, H. W. A. M.

    2015-05-01

    Dynamic contrast enhanced CT (DCE-CT) can be used to estimate blood perfusion and vessel permeability in tumors. Tumor induced angiogenesis is generally associated with disorganized microvasculature with increased permeability or leakage. Estimated vascular leakage (Ktrans) values and their reliability greatly depend on the perfusion model used. To identify the preferred model for larynx tumor analysis, several perfusion models frequently used for estimating permeability were compared in this study. DCE-CT scans were acquired for 16 larynx cancer patients. Larynx tumors were delineated based on whole-mount histopathology after laryngectomy. DCE-CT data within these delineated volumes were analyzed using the Patlak and Logan plots, the Extended Tofts Model (ETM), the Adiabatic Approximation to the Tissue Homogeneity model (AATH) and a variant of AATH with fixed transit time (AATHFT). Akaike’s Information Criterion (AIC) was used to identify the best fitting model. Ktrans values from all models were compared with this best fitting model. Correlation strength was tested with two-tailed Spearman’s rank correlation and further examined using Bland-Altman plots. AATHFT was found to be the best fitting model. The overall median of individual patient medians Ktrans estimates were 14.3, 15.1, 16.1, 2.6 and 22.5 mL/100 g min  -  1 for AATH, AATHFT, ETM, Patlak and Logan, respectively. Ktrans estimates for all models except Patlak were strongly correlated (P  <  0.001). Bland-Altman plots show large biases but no significant deviating trend for any model other than Patlak. AATHFT was found to be the preferred model among those tested for estimation of Ktrans in larynx tumors.

  15. Preoperative imaging of liver metastases. Comparison of angiography, CT scan, and ultrasonography.

    PubMed Central

    Gunvén, P; Makuuchi, M; Takayasu, K; Moriyama, N; Yamasaki, S; Hasegawa, H

    1985-01-01

    Thirty-one patients with mostly colorectal cancer metastases to the liver had preoperative selective/superselective angiograms (24 cases), computed tomography (CT) [26 cases, mostly enhanced by contrast administered by a peripheral vein (9), the common hepatic artery (9), or the portal vein (5)], and ultrasonography (26 cases). Intraoperative ultrasonography and palpation and examination of the resected specimens revealed 113 tumors. CT detected almost half of the masses smaller than 1 cm, and ultrasonography and angiography about one-third of lesions 1-2 cm in size. Ultrasonography was less powerful for examination of the posterior segment of the liver. CT and ultrasonography placed the tumors into subsegments more accurately than did angiography. Almost 40% of the preoperative plans had to be changed: in two-thirds by extended resections and in one-third by a change from curative to palliative intent. Most changes were due to extrahepatic tumor growth, often within areas screened before surgery. The use of all three imaging modalities for liver metastases is recommended for preoperative planning. PMID:3901943

  16. Comparison of two detector systems for cone beam CT small animal imaging - a preliminary study

    PubMed Central

    Meng, Yang; Shaw, Chris C.; Liu, Xinming; Altunbas, Mustafa C.; Wang, Tianpeng; Chen, Lingyun; Tu, Shu-Ju; Kappadath, S. Cheenu; Lai, Chao-Jen

    2007-01-01

    Purpose To compare two detector systems - one based on the charge-coupled device (CCD) and image amplifier, the other based on a-Si/CsI flat panel, for cone beam computed-tomography (CT) imaging of small animals. A high resolution, high framing rate detector system for the cone beam CT imaging of small animals was developed. The system consists of a 2048×3072×12 bit CCD optically coupled to an image amplifier and an x-ray phosphor screen. The CCD has an intrinsic pixel size of 12 μm but the effective pixel size can be adjusted through the magnification adjustment of the optical coupling systems. The system is used in conjunction with an x-ray source and a rotating stage for holding and rotating the scanned object in the cone beam CT imaging experiments. The advantages of the system include but are not limited to the ability to adjust the effective pixel size and to achieve extremely high spatial resolution and temporal resolution. However, the need to use optical coupling compromises the detective quanta efficiency (DQE) of the system. In this paper, the imaging characteristics of the system were presented and compared with those of an a-Si/CsI flat-panel detector system. PMID:18160972

  17. The relevance of MRI for patient modeling in head and neck hyperthermia treatment planning: A comparison of CT and CT-MRI based tissue segmentation on simulated temperature

    SciTech Connect

    Verhaart, René F. Paulides, Margarethus M.; Fortunati, Valerio; Walsum, Theo van; Veenland, Jifke F.; Lugt, Aad van der

    2014-12-15

    Purpose: In current clinical practice, head and neck (H and N) hyperthermia treatment planning (HTP) is solely based on computed tomography (CT) images. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast over CT. The purpose of the authors’ study is to investigate the relevance of using MRI in addition to CT for patient modeling in H and N HTP. Methods: CT and MRI scans were acquired for 11 patients in an immobilization mask. Three observers manually segmented on CT, MRI T1 weighted (MRI-T1w), and MRI T2 weighted (MRI-T2w) images the following thermo-sensitive tissues: cerebrum, cerebellum, brainstem, myelum, sclera, lens, vitreous humor, and the optical nerve. For these tissues that are used for patient modeling in H and N HTP, the interobserver variation of manual tissue segmentation in CT and MRI was quantified with the mean surface distance (MSD). Next, the authors compared the impact of CT and CT and MRI based patient models on the predicted temperatures. For each tissue, the modality was selected that led to the lowest observer variation and inserted this in the combined CT and MRI based patient model (CT and MRI), after a deformable image registration. In addition, a patient model with a detailed segmentation of brain tissues (including white matter, gray matter, and cerebrospinal fluid) was created (CT and MRI{sub db}). To quantify the relevance of MRI based segmentation for H and N HTP, the authors compared the predicted maximum temperatures in the segmented tissues (T{sub max}) and the corresponding specific absorption rate (SAR) of the patient models based on (1) CT, (2) CT and MRI, and (3) CT and MRI{sub db}. Results: In MRI, a similar or reduced interobserver variation was found compared to CT (maximum of median MSD in CT: 0.93 mm, MRI-T1w: 0.72 mm, MRI-T2w: 0.66 mm). Only for the optical nerve the interobserver variation is significantly lower in CT compared to MRI (median MSD in CT: 0.58 mm, MRI-T1w: 1.27 mm, MRI-T2w: 1.40 mm

  18. Alcoholic Women on Skid Row.

    ERIC Educational Resources Information Center

    Anderson, Sandra C.

    1987-01-01

    Examined women (N=20) who were receiving alcoholism treatment in the skid-row area of Portland, Oregon. Women had histories of problem drinking and extensive treatment for alcoholism. Most had been married and had children. Despite transiency, the majority maintained contact with friends and relatives. Compared these women to New York City's…

  19. A Comparison of Techniques for 90Y PET/CT Image-Based Dosimetry Following Radioembolization with Resin Microspheres

    PubMed Central

    Pasciak, Alexander S.; Bourgeois, Austin C.; Bradley, Yong C.

    2014-01-01

    90Y PET/CT following radioembolization has recently been established as a viable diagnostic tool, capable of producing images that are both quantitative and have superior image quality than alternative 90Y imaging modalities. Because radioembolization is assumed to be a permanent implant, it is possible to convert quantitative 90Y PET image sets into data representative of spatial committed absorbed-dose. Multiple authors have performed this transformation using dose-point kernel (DPK) convolution to account for the transport of the high-energy 90Y β-particles. This article explores a technique called the Local Deposition Method (LDM), an alternative to DPK convolution for 90Y image-based dosimetry. The LDM assumes that the kinetic energy from each 90Y β-particle is deposited locally, within the voxel where the decay occurred. Using the combined analysis of phantoms scanned using 90Y PET/CT and ideal mathematical phantoms, an accuracy comparison of DPK convolution and the LDM has been performed. Based on the presented analysis, DPK convolution provides no detectible accuracy benefit over the LDM for 90Y PET-based dosimetry. For PET systems with 90Y resolution poorer than 3.25 mm at full-width and half-max using a small voxel size, the LDM may produce a dosimetric solution that is more accurate than DPK convolution under ideal conditions; however, image noise can obscure some of the perceived benefit. As voxel size increases and resolution decreases, differences between the LDM and DPK convolution are reduced. The LDM method of post-radioembolization dosimetry has the advantage of not requiring additional post-processing. The provided conversion factors can be used to determine committed absorbed-dose using conventional PET image analysis tools. The LDM is a recommended option for routine post-radioembolization 90Y dosimetry based on PET/CT imaging. PMID:24904832

  20. Mechanical performance of aquatic rowing and flying.

    PubMed Central

    Walker, J A; Westneat, M W

    2000-01-01

    Aquatic flight, performed by rowing or flapping fins, wings or limbs, is a primary locomotor mechanism for many animals. We used a computer simulation to compare the mechanical performance of rowing and flapping appendages across a range of speeds. Flapping appendages proved to be more mechanically efficient than rowing appendages at all swimming speeds, suggesting that animals that frequently engage in locomotor behaviours that require energy conservation should employ a flapping stroke. The lower efficiency of rowing appendages across all speeds begs the question of why rowing occurs at all. One answer lies in the ability of rowing fins to generate more thrust than flapping fins during the power stroke. Large forces are necessary for manoeuvring behaviours such as accelerations, turning and braking, which suggests that rowing should be found in slow-swimming animals that frequently manoeuvre. The predictions of the model are supported by observed patterns of behavioural variation among rowing and flapping vertebrates. PMID:11052539

  1. A comparison of simulation tools for photon-counting spectral CT

    NASA Astrophysics Data System (ADS)

    Nasirudin, Radin A.; Penchev, Petar; Mei, Kai; Rummeny, Ernst J.; Fiebich, Martin; Noël, Peter B.

    2014-03-01

    Photon-counting detectors (PCD) not only have the advantage of providing spectral information but also offer high quantum efficiencies, producing high image quality in combination with a minimal amount of radiation dose. Due to the clinical unavailability of photon-counting CT, the need to evaluate different CT simulation tools for researching different applications for photon-counting systems is essential. In this work, we investigate two different methods to simulate PCD data: Monte-Carlo based simulation (MCS) and analytical based simulation (AS). The MCS is a general-purpose photon transport simulation based on EGSnrc C++ class library. The AS uses analytical forward-projection in combination with additional acquisition parameters. MCS takes into account all physical effects, but is computationally expensive (several days per CT acquisition). AS is fast (several minutes), but lacks the accurateness of MCS with regard to physical interactions. To evaluate both techniques an entrance spectra of 100kvp, a modified CTP515 module of the CatPhan 600 phantom, and a detector system with six thresholds was simulated. For evaluation the simulated projection data are decomposed via a maximum likelihood technique, and reconstructed via standard filtered-back projection (FBP). Image quality from both methods is subjectively and objectively assessed. Visually, the difference in the image quality was not significant. When further evaluated, the relative difference was below 4%. As a conclusion, both techniques offer different advantages, while at different stages of development the accelerated calculations via AS can make a significant difference. For the future one could foresee a combined method to join accuracy and speed.

  2. MRI experience with multiple sclerosis - Comparison to CT and clinical status

    SciTech Connect

    Reese, L.; Carr, T.; Nicholson, R.L.

    1985-05-01

    A Multiple Sclerosis (M.S.) Protocol was set--SEB (1000/60) volume acquisition and selected single slices SEC (1000/120) and IR (1500/450). Single slices SE 500/30, 1500/30 and 1530/60 were obtained for T1 and T2 calculation. New software and coils permitted multi-slice multi-echo acquisition so the Protocol was changed to multi-slice multi-echo transaxial SE 2120/60-120, and the T1 and T2 sets. The study consisted of 62 known M.S. patients and 35 controls. Of the 62 M.S. patients, 58 (94%) were positive on NMR. Thirty-two of these patients had CT scans of which 17 (53%) were positive. Of the 35 controls, 2 were positive on NMR for a false positive rate of 6%. The relative sensitivity of NMR, Double Dose Delayed CT(DDD) and contrast CT in the clinically early progressive group is 87%, 60% and 45% respectively. In the chronic stable group, the sensitivity is 100% for NMR and 55% for DDD. The NMR lesions were graded on a scale of 1 - 4 and the authors found poor correlation with either duration of disease or Kurtzke Functional Scale. The T1, T2 values showed good differentiation between white matter and lesions, although differentiation between lesions and grey matter was poor. White matter has T1 of 328 +- 28 and T2 of 85 +- 22, grey matter T1 of 515 +- 37 and T2 of 96 +- 32 and lesions T1 of 530 +- 76 and T2 of 106 +- 27. They conclude that multi-slice SE 2120/60-120 NMR imaging has proven to be a valuable tool in the clinical diagnosis of Multiple Sclerosis. Most of the lesions seen are asymptomatic and the number, size and distribution of lesions have little correlation with severity or acuity of the disease.

  3. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  4. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    SciTech Connect

    Zanca, F.; Jacobs, A.; Crijns, W.; De Wever, W.

    2014-07-15

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure.

  5. Performance comparison of two commercial BGO-based PET/CT scanners using NEMA NU 2-2001

    SciTech Connect

    Bolard, Gregory; Prior, John O.; Modolo, Luca; Bischof Delaloye, Angelika; Kosinski, Marek; Wastiel, Claude; Malterre, Jerome; Bulling, Shelley; Bochud, Francois; Verdun, Francis R.

    2007-07-15

    Combined positron emission tomography and computed tomography (PET/CT) scanners play a major role in medicine for in vivo imaging in an increasing number of diseases in oncology, cardiology, neurology, and psychiatry. With the advent of short-lived radioisotopes other than {sup 18}F and newer scanners, there is a need to optimize radioisotope activity and acquisition protocols, as well as to compare scanner performances on an objective basis. The Discovery-LS (D-LS) was among the first clinical PET/CT scanners to be developed and has been extensively characterized with older National Electrical Manufacturer Association (NEMA) NU 2-1994 standards. At the time of publication of the latest version of the standards (NU 2-2001) that have been adapted for whole-body imaging under clinical conditions, more recent models from the same manufacturer, i.e., Discovery-ST (D-ST) and Discovery-STE (D-STE), were commercially available. We report on the full characterization both in the two- and three-dimensional acquisition mode of the D-LS according to latest NEMA NU 2-2001 standards (spatial resolution, sensitivity, count rate performance, accuracy of count losses, and random coincidence correction and image quality), as well as a detailed comparison with the newer D-ST widely used and whose characteristics are already published.

  6. Skeletal dosimetry based on µCT images of trabecular bone: update and comparisons

    NASA Astrophysics Data System (ADS)

    Kramer, R.; Cassola, V. F.; Vieira, J. W.; Khoury, H. J.; de Oliveira Lira, C. A. B.; Robson Brown, K.

    2012-06-01

    Two skeletal dosimetry methods using µCT images of human bone have recently been developed: the paired-image radiation transport (PIRT) model introduced by researchers at the University of Florida (UF) in the US and the systematic-periodic cluster (SPC) method developed by researchers at the Federal University of Pernambuco in Brazil. Both methods use µCT images of trabecular bone (TB) to model spongiosa regions of human bones containing marrow cavities segmented into soft tissue volumes of active marrow (AM), trabecular inactive marrow and the bone endosteum (BE), which is a 50 µm thick layer of marrow on all TB surfaces and on cortical bone surfaces next to TB as well as inside the medullary cavities. With respect to the radiation absorbed dose, the AM and the BE are sensitive soft tissues for the induction of leukaemia and bone cancer, respectively. The two methods differ mainly with respect to the number of bone sites and the size of the µCT images used in Monte Carlo calculations and they apply different methods to simulate exposure from radiation sources located outside the skeleton. The PIRT method calculates dosimetric quantities in isolated human bones while the SPC method uses human bones embedded in the body of a phantom which contains all relevant organs and soft tissues. Consequently, the SPC method calculates absorbed dose to the AM and to the BE from particles emitted by radionuclides concentrated in organs or from radiation sources located outside the human body in one calculation step. In order to allow for similar calculations of AM and BE absorbed doses using the PIRT method, the so-called dose response functions (DRFs) have been developed based on absorbed fractions (AFs) of energy for electrons isotropically emitted in skeletal tissues. The DRFs can be used to transform the photon fluence in homogeneous spongiosa regions into absorbed dose to AM and BE. This paper will compare AM and BE AFs of energy from electrons emitted in skeletal

  7. Bilateral Second Carpal Row Duplication Associated with Multiple Epiphyseal Dysplasia.

    PubMed

    Cladiere-Nassif, Victoire; Delaroche, Caroline; Pottier, Edwige; Feron, Jean-Marc

    2015-11-01

    We report a case of a 75-year-old woman presenting a hitherto undescribed condition of bilateral second carpal row duplication. She was diagnosed in childhood with both Marfan and Ehlers-Danlos syndromes, with no clear evidence and no further medical follow-up. She presented throughout her life with various articular symptoms, which appeared to be compatible with a diagnosis of multiple epiphyseal dysplasia, and underwent several surgical procedures on her knees and hips. Most recently, she was reporting pain at the base of the fifth metacarpal bone of the left hand. X-ray images and computed tomography (CT) were obtained for exploration and showed a total second row duplication in both carpi, with a total number of 18 carpal bones in each wrist. PMID:26649258

  8. Comparison between human and model observer performance in low-contrast detection tasks in CT images: application to images reconstructed with filtered back projection and iterative algorithms

    PubMed Central

    Calzado, A; Geleijns, J; Joemai, R M S; Veldkamp, W J H

    2014-01-01

    Objective: To compare low-contrast detectability (LCDet) performance between a model [non–pre-whitening matched filter with an eye filter (NPWE)] and human observers in CT images reconstructed with filtered back projection (FBP) and iterative [adaptive iterative dose reduction three-dimensional (AIDR 3D; Toshiba Medical Systems, Zoetermeer, Netherlands)] algorithms. Methods: Images of the Catphan® phantom (Phantom Laboratories, New York, NY) were acquired with Aquilion ONE™ 320-detector row CT (Toshiba Medical Systems, Tokyo, Japan) at five tube current levels (20–500 mA range) and reconstructed with FBP and AIDR 3D. Samples containing either low-contrast objects (diameters, 2–15 mm) or background were extracted and analysed by the NPWE model and four human observers in a two-alternative forced choice detection task study. Proportion correct (PC) values were obtained for each analysed object and used to compare human and model observer performances. An efficiency factor (η) was calculated to normalize NPWE to human results. Results: Human and NPWE model PC values (normalized by the efficiency, η = 0.44) were highly correlated for the whole dose range. The Pearson's product-moment correlation coefficients (95% confidence interval) between human and NPWE were 0.984 (0.972–0.991) for AIDR 3D and 0.984 (0.971–0.991) for FBP, respectively. Bland–Altman plots based on PC results showed excellent agreement between human and NPWE [mean absolute difference 0.5 ± 0.4%; range of differences (−4.7%, 5.6%)]. Conclusion: The NPWE model observer can predict human performance in LCDet tasks in phantom CT images reconstructed with FBP and AIDR 3D algorithms at different dose levels. Advances in knowledge: Quantitative assessment of LCDet in CT can accurately be performed using software based on a model observer. PMID:24837275

  9. Comparison of Airflows in Weibel-based and CT-based Human Lung Geometries

    NASA Astrophysics Data System (ADS)

    Lin, Ching-Long; Hoffman, Eric A.

    2004-11-01

    The need for patient specific lung geometry for study of pulmonary air flow and drug delivery has been emphasized recently due to the complexity of individual airway tree geometry. The objective of this paper is to assess the notion of patient specific geometry by comparing airflows in an idealized Weibel-based lung model and two realistic human lung geometries. The Weibel-based model is composed of cylinders of differing diameters for various branching and has been used extensively for modeling airflow in lungs. Here a 4-generation Weibel model is considered. The realistic lung geometries are segmented and reconstructured from computerized tomography (CT) images as part of an effort to build a normative atlas (NIH HL-04368) documenting airway geometry over 4 decades of age in healthy and disease-state adult humans. The custom developed Taylor-Galerkin finite element code, which solves the incompressible Navier-Stokes equations, is applied to simulate airflows in these lung geometries. The velocity wave form recorded from a mechanical ventilator is adopted as the inlet pulsatile boundary condition. At the outlets, both the pressure and outflow boundary conditions are applied and compared. The counter-rotating vortices are observed in the Weibel model during both the inspiratory and expiratory cycles, being consistent with previous studies. The flow structures in the CT-based models are much more complicated and counter-rotating vortices are only evident in some regions.

  10. Billet planting, 8-foot rows, residue updates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultural practices are continually tested and upgraded to maximize sugarcane yield in Louisiana. Over the past 3 years extensive research went in to comparing the industry standard 6-foot row spacing to a wider, 8 foot row. Each 8 foot row was double drilled with seed canes that were 2-3 feet apart....

  11. X-ray CT analyses, models and numerical simulations: a comparison with petrophysical analyses in an experimental CO2 study

    NASA Astrophysics Data System (ADS)

    Henkel, Steven; Pudlo, Dieter; Enzmann, Frieder; Reitenbach, Viktor; Albrecht, Daniel; Ganzer, Leonhard; Gaupp, Reinhard

    2016-06-01

    An essential part of the collaborative research project H2STORE (hydrogen to store), which is funded by the German government, was a comparison of various analytical methods for characterizing reservoir sandstones from different stratigraphic units. In this context Permian, Triassic and Tertiary reservoir sandstones were analysed. Rock core materials, provided by RWE Gasspeicher GmbH (Dortmund, Germany), GDF Suez E&P Deutschland GmbH (Lingen, Germany), E.ON Gas Storage GmbH (Essen, Germany) and RAG Rohöl-Aufsuchungs Aktiengesellschaft (Vienna, Austria), were processed by different laboratory techniques; thin sections were prepared, rock fragments were crushed and cubes of 1 cm edge length and plugs 3 to 5 cm in length with a diameter of about 2.5 cm were sawn from macroscopic homogeneous cores. With this prepared sample material, polarized light microscopy and scanning electron microscopy, coupled with image analyses, specific surface area measurements (after Brunauer, Emmet and Teller, 1938; BET), He-porosity and N2-permeability measurements and high-resolution microcomputer tomography (μ-CT), which were used for numerical simulations, were applied. All these methods were practised on most of the same sample material, before and on selected Permian sandstones also after static CO2 experiments under reservoir conditions. A major concern in comparing the results of these methods is an appraisal of the reliability of the given porosity, permeability and mineral-specific reactive (inner) surface area data. The CO2 experiments modified the petrophysical as well as the mineralogical/geochemical rock properties. These changes are detectable by all applied analytical methods. Nevertheless, a major outcome of the high-resolution μ-CT analyses and following numerical data simulations was that quite similar data sets and data interpretations were maintained by the different petrophysical standard methods. Moreover, the μ-CT analyses are not only time saving, but also

  12. Three dimensional dose distribution comparison of simple and complex acquisition trajectories in dedicated breast CT

    PubMed Central

    Shah, Jainil P.; Mann, Steve D.; McKinley, Randolph L.; Tornai, Martin P.

    2015-01-01

    Purpose: A novel breast CT system capable of arbitrary 3D trajectories has been developed to address cone beam sampling insufficiency as well as to image further into the patient’s chest wall. The purpose of this study was to characterize any trajectory-related differences in 3D x-ray dose distribution in a pendant target when imaged with different orbits. Methods: Two acquisition trajectories were evaluated: circular azimuthal (no-tilt) and sinusoidal (saddle) orbit with ±15° tilts around a pendant breast, using Monte Carlo simulations as well as physical measurements. Simulations were performed with tungsten (W) filtration of a W-anode source; the simulated source flux was normalized to the measured exposure of a W-anode source. A water-filled cylindrical phantom was divided into 1 cm3 voxels, and the cumulative energy deposited was tracked in each voxel. Energy deposited per voxel was converted to dose, yielding the 3D distributed dose volumes. Additionally, three cylindrical phantoms of different diameters (10, 12.5, and 15 cm) and an anthropomorphic breast phantom, initially filled with water (mimicking pure fibroglandular tissue) and then with a 75% methanol-25% water mixture (mimicking 50–50 fibroglandular-adipose tissues), were used to simulate the pendant breast geometry and scanned on the physical system. Ionization chamber calibrated radiochromic film was used to determine the dose delivered in a 2D plane through the center of the volume for a fully 3D CT scan using the different orbits. Results: Measured experimental results for the same exposure indicated that the mean dose measured throughout the central slice for different diameters ranged from 3.93 to 5.28 mGy, with the lowest average dose measured on the largest cylinder with water mimicking a homogeneously fibroglandular breast. These results align well with the cylinder phantom Monte Carlo studies which also showed a marginal difference in dose delivered by a saddle trajectory in the

  13. Comparison of effective radiation doses from X-ray, CT, and PET/CT in pediatric patients with neuroblastoma using a dose monitoring program

    PubMed Central

    Kim, Yeun Yoon; Shin, Hyun Joo; Kim, Myung-Joon; Lee, Mi-Jung

    2016-01-01

    PURPOSE We aimed to evaluate the use of a dose monitoring program for calculating and comparing the diagnostic radiation doses in pediatric patients with neuroblastoma. METHODS We retrospectively reviewed diagnostic and therapeutic imaging studies performed on pediatric patients with neuroblastoma from 2003 to 2014. We calculated the mean effective dose per exam for X-ray, conventional computed tomography (CT), and CT of positron emission tomography/computed tomography (PET/CT) from the data collected using a dose monitoring program (DoseTrack group) since October 2012. Using the data, we estimated the cumulative dose per person and the relative dose from each modality in all patients (Total group). The effective dose from PET was manually calculated for all patients. RESULTS We included 63 patients with a mean age of 3.2±3.5 years; 28 had a history of radiation therapy, with a mean irradiated dose of 31.9±23.2 Gy. The mean effective dose per exam was 0.04±0.19 mSv for X-ray, 1.09±1.11 mSv for CT, and 8.35±7.45 mSv for CT of PET/CT in 31 patients of the Dose-Track group. The mean estimated cumulative dose per patient in the Total group was 3.43±2.86 mSv from X-ray (8.5%), 7.66±6.09 mSv from CT (19.1%), 18.35±13.52 mSv from CT of PET/CT (45.7%), and 10.71±10.05 mSv from PET (26.7%). CONCLUSION CT of PET/CT contributed nearly half of the total cumulative dose in pediatric patients with neuroblastoma. The radiation dose from X-ray was not negligible because of the large number of X-ray images. A dose monitoring program can be useful for calculating radiation doses in patients with cancer. PMID:27306659

  14. BrachyView: multiple seed position reconstruction and comparison with CT post-implant dosimetry

    NASA Astrophysics Data System (ADS)

    Alnaghy, S.; Loo, K. J.; Cutajar, D. L.; Jalayer, M.; Tenconi, C.; Favoino, M.; Rietti, R.; Tartaglia, M.; Carriero, F.; Safavi-Naeini, M.; Bucci, J.; Jakubek, J.; Pospisil, S.; Zaider, M.; Lerch, M. L. F.; Rosenfeld, A. B.; Petasecca, M.

    2016-05-01

    BrachyView is a novel in-body imaging system utilising high-resolution pixelated silicon detectors (Timepix) and a pinhole collimator for brachytherapy source localisation. Recent studies have investigated various options for real-time intraoperative dynamic dose treatment planning to increase the quality of implants. In a previous proof-of-concept study, the justification of the pinhole concept was shown, allowing for the next step whereby multiple active seeds are implanted into a PMMA phantom to simulate a more realistic clinical scenario. In this study, 20 seeds were implanted and imaged using a lead pinhole of 400 μ m diameter. BrachyView was able to resolve the seed positions within 1–2 mm of expected positions, which was verified by co-registering with a full clinical post-implant CT scan.

  15. Comparisons of obesity assessments in over-weight elementary students using anthropometry, BIA, CT and DEXA

    PubMed Central

    Yu, Ok-Kyeong; Rhee, Yang-Keun; Park, Tae-Sun

    2010-01-01

    Obesity was characterized in Korean elementary students using different obesity assessment tests on 103 overweight elementary students from three schools of Jeonbuk Province. The body mass index (BMI) and obesity index (OI) were compared, and the data using DEXA and CT were compared with the data using BIA and a tape measure. The results of this study are as follows: first, 27 students who were classified as obese by OI were classified as overweight by BMI, and 3 students who were classified as standard weight by BMI were classified as overweight by OI. Secondly, by DEXA and BIA measurements, there was 1.51% difference in body fat percentage (boys 1.66%, girls 1.17%) and the difference in body fat mass between boys and girls was 0.77 kg (boys 0.85 kg, girls 0.59 kg), but those differences in body fat percentage and mass were not statistically significant. Thirdly, the average total abdominal fat (TAF) measured by CT scans of obese children was more significantly related with subcutaneous fat (r = 0.983, P < 0.01) than visceral fat (r = 0.640, P < 0.01). Also, TAF were highest significant with waist circumference by a tape measure (r = 0.744, P < 0.01). In summary, as there are some differences of assessment results between two obesity test methods (BMI, OI), we need more definite standards to determine the degree of obesity. The BIA seems to be the most simple and effective way to measure body fat mass, whereas waist/hip ratio (WHR) using a tape measurer is considered to be the most effective method for assessing abdominal fat in elementary students. PMID:20461201

  16. Contrast agent comparison for three-dimensional micro-CT angiography: A cadaveric study.

    PubMed

    Kingston, Mitchell J; Perriman, Diana M; Neeman, Teresa; Smith, Paul N; Webb, Alexandra L

    2016-07-01

    Barium sulfate and lead oxide contrast media are frequently used for cadaver-based angiography studies. These contrast media have not previously been compared to determine which is optimal for the visualisation and measurement of blood vessels. In this study, the lower limb vessels of 16 embalmed Wistar rats, and four sets of cannulae of known diameter, were injected with one of three different contrast agents (barium sulfate and resin, barium sulfate and gelatin, and lead oxide combined with milk powder). All were then scanned using micro-computed tomography (CT) angiography and 3-D reconstructions generated. The number of branching generations of the rat lower limb vessels were counted and compared between the contrast agents using ANOVA. The diameter of the contrast-filled cannulae, were measured and used to calculate the accuracy of the measurements by comparing the bias and variance of the estimates. Intra- and inter-observer reliability were calculated using intra-class correlation coefficients. There was no significant difference (mean difference [MD] 0.05; MD 95% confidence interval [CI] -0.83 to 0.93) between the number of branching generations for barium sulfate-resin and lead oxide-milk powder. Barium sulfate-resin demonstrated less bias and less variance of the estimates (MD 0.03; standard deviation [SD] 1.96 mm) compared to lead oxide-milk powder (MD 0.11; SD 1.96 mm) for measurements of contrast-filled cannulae scanned at high resolution. Barium sulfate-resin proved to be more accurate than lead oxide-milk powder for high resolution micro-CT scans and is preferred due to its non-toxicity. This technique could be applied to any embalmed specimen model. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27075920

  17. Feasibility of low-concentration iodinated contrast medium with lower-tube-voltage dual-source CT aortography using iterative reconstruction: comparison with automatic exposure control CT aortography.

    PubMed

    Shin, Hee Jeong; Kim, Song Soo; Lee, Jae-Hwan; Park, Jae-Hyeong; Jeong, Jin-Ok; Jin, Seon Ah; Shin, Byung Seok; Shin, Kyung-Sook; Ahn, Moonsang

    2016-06-01

    To evaluate the feasibility of low-concentration contrast medium (CM) for vascular enhancement, image quality, and radiation dose on computed tomography aortography (CTA) using a combined low-tube-voltage and iterative reconstruction (IR) technique. Ninety subjects underwent dual-source CT (DSCT) operating in dual-source, high-pitch mode. DSCT scans were performed using both high-concentration CM (Group A, n = 50; Iomeprol 400) and low-concentration CM (Group B, n = 40; Iodixanol 270). Group A was scanned using a reference tube potential of 120 kVp and 120 reference mAs under automatic exposure control with IR. Group B was scanned using low-tube-voltage (80 or 100 kVp if body mass index ≥25 kg/m(2)) at a fixed current of 150 mAs, along with IR. Images of the two groups were compared regarding attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), iodine load, and radiation dose in various locations of the CTA. In comparison between Group A and Group B, the average mean attenuation (454.73 ± 86.66 vs. 515.96 ± 101.55 HU), SNR (25.28 ± 4.34 vs. 31.29 ± 4.58), and CNR (21.83 ± 4.20 vs. 27.55 ± 4.81) on CTA in Group B showed significantly greater values and significantly lower image noise values (18.76 ± 2.19 vs. 17.48 ± 3.34) than those in Group A (all Ps < 0.05). Homogeneous contrast enhancement from the ascending thoracic aorta to the infrarenal abdominal aorta was significantly superior in Group B (P < 0.05). Low-concentration CM and a low-tube-voltage combination technique using IR is a feasible method, showing sufficient contrast enhancement and image quality. PMID:26621755

  18. Dual-energy performance of dual kVp in comparison to dual-layer and quantum-counting CT system concepts

    NASA Astrophysics Data System (ADS)

    Kappler, S.; Grasruck, M.; Niederlöhner, D.; Strassburg, M.; Wirth, S.

    2009-02-01

    Recent publications in the field of Computed Tomography (CT) demonstrate the rising interest in applying dual-energy methods for material classification during clinical routine examinations. Based on today's standard of technology, dual-energy CT can be realized by either scanning with different X-ray spectra or by deployment of energy selective detector technologies. The list of so-called dual-kVp methods contains sequential scans, fast kVp-switching and dual-source CT. Examples of energy selective detectors are scintillator-based energyintegrating dual-layer devices or direct converter with quantum counting electronics. The general difference of the approaches lies in the shape of the effectively detected X-ray energy spectra and in the presence of crossscatter radiation in the case of dual-source devices. This leads to different material classification capabilities for the various techniques. In this work, we present detector response simulations of realistic CT scans with subsequent CT image reconstruction. Analysis of the image data allows direct and objective comparison of the dual-kVp, dual-layer, and quantum counting CT system concepts. The dual-energy performance is benchmarked in terms of image noise and Iodine-bone separation power at given image sharpness and dose exposure. For the case of dual-source devices the effect of cross-scatter radiation, as well as the benefit of additional filtering are taken into account.

  19. Two-dimensional cold-air cascade study of a film-cooled turbine stator blade. 5: Comparison of experimental and analytical aerodynamic results for blade with 12 rows of 0.038-centimeter-(0.015 inch) diameter coolant holes having streamwise ejection angles

    NASA Technical Reports Server (NTRS)

    Prust, H. W., Jr.

    1978-01-01

    Published experimental aerodynamic efficiency results were compared with results predicted from two published analytical methods. This is the second of two such comparisons. One of the analytical methods was used as published; the other was modified for certain cases of coolant discharge from the blade suction surface. The results show that for 23 cases of single row and multirow discharge covering coolant fractions from 0 to about 9 percent, the difference between the experimental and predicted results was no greater than about 1 percent in any case and less than 1/2 percent in most cases.

  20. Comparison of CT and MR in 400 patients with suspected disease of the brain and cervical spinal cord

    SciTech Connect

    Bradley, W.G. Jr.; Waluch, V.; Yadley, R.A.; Wycoff, R.R.

    1984-09-01

    Magnetic resonance imaging (MR) (0.35T) and computed tomography (CT) were compared in 400 consecutive patients with suspected disease of the brain and cervical spinal cord. Of 325 positive diagnoses, MR detected abnormality while CT was normal in 93; MR was more specific in 68; MR and CT gave equivalent information in 129; CT was more specific in 32; and CT was positive while MR was normal in 3. MR was superior to CT in detection of multiple sclerosis, subcortical arteriosclerotic encephalopathy, posterior fossa infarcts and tumors, small extra-axial fluid collections, and cervical syringomyelia. CT was preferable in evaluation of meningiomas and separation of tumor from edema. CT takes less time and may be preferable in patients with acute trauma as well as very young or elderly individuals. Thus the two studies should be considered complementary.

  1. A Comparison between a SNOMED CT Problem List and the ICD-10-CM/PCS HIPAA Code Sets

    PubMed Central

    Steindel, Steven J

    2012-01-01

    In 2013 the United States will convert from the use of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) to the use of the International Classification of Diseases, Tenth Revision, Clinical Modification/Procedure Coding System (ICD-10-CM/PCS). This study compares the approximately 5,000 terms in the July 2009 Clinical Observations Recording and Encoding (CORE) Problem List subset of the Systematized Nomenclature of Medicine–Clinical Terms (SNOMED CT) terminology produced by the National Library of Medicine with terms found in the January 2009 versions of ICD-10-CM/PCS. The comparison was done by a single individual and used the internally defined concepts of “Exact,” “Inexact,” “Model” (one SNOMED CT term to many ICD-10-CM/PCS terms), “Not Elsewhere Classified,” “Not Otherwise Specified,” “Synonym,” and “Not Found” to classify the CORE Problem List terms according to the quality of the match. Among the CORE Problem List terms, 6.0 percent were not found in ICD-10-CM/PCS, and 69.1 percent had equivalent ICD-10-CM/PCS terms. The 13.0 percent of terms classified as “Inexact” could also be used directly assuming some acceptable loss of clinical precision. The 11.9 percent of terms classified as “Model” represent differences that require rule-based mapping. The results of this study suggest that ICD-10-CM/PCS meets the intended design goal of increased clinical precision but studies are needed to precisely define the depth of coverage. PMID:22548020

  2. Comparisons of Derived Metrics from Computed Tomography (CT) Scanned Images of Fluvial Sediment from Gravel-Bed Flume Experiments

    NASA Astrophysics Data System (ADS)

    Voepel, Hal; Ahmed, Sharif; Hodge, Rebecca; Leyland, Julian; Sear, David

    2016-04-01

    Uncertainty in bedload estimates for gravel bed rivers is largely driven by our inability to characterize arrangement, orientation and resultant forces of fluvial sediment in river beds. Water working of grains leads to structural differences between areas of the bed through particle sorting, packing, imbrication, mortaring and degree of bed armoring. In this study, non-destructive, micro-focus X-ray computed tomography (CT) imaging in 3D is used to visualize, quantify and assess the internal geometry of sections of a flume bed that have been extracted keeping their fabric intact. Flume experiments were conducted at 1:1 scaling of our prototype river. From the volume, center of mass, points of contact, and protrusion of individual grains derived from 3D scan data we estimate 3D static force properties at the grain-scale such as pivoting angles, buoyancy and gravity forces, and local grain exposure. Here metrics are derived for images from two flume experiments: one with a bed of coarse grains (>4mm) and the other where sand and clay were incorporated into the coarse flume bed. In addition to deriving force networks, comparison of metrics such as critical shear stress, pivot angles, grain distributions, principle axis orientation, and pore space over depth are made. This is the first time bed stability has been studied in 3D using CT scanned images of sediment from the bed surface to depths well into the subsurface. The derived metrics, inter-granular relationships and characterization of bed structures will lead to improved bedload estimates with reduced uncertainty, as well as improved understanding of relationships between sediment structure, grain size distribution and channel topography.

  3. CT detection of facial canal dehiscence and semicircular canal fistula: Comparison with surgical findings

    SciTech Connect

    Fuse, Takeo; Tada, Yuichiro; Aoyagi, Masaru; Sugai, Yukio

    1996-03-01

    The purpose of this study was to determine the accuracy of high resolution CT (HRCT) in the detection of facial canal dehiscence and semicircular canal fistula, the preoperative evaluation of both of which is clinically very important for ear surgery. We retrospectively reviewed the HRCT findings in 61 patients who underwent mastoidectomy at Yamagata University between 1989 and 1993. The HRCT images were obtained in the axial and semicoronal planes using 1 mm slice thickness and 1 mm intersection gap. In 46 (75%) of the 61 patients, the HRCT image-based assessment of the facial canal dehiscence coincided with the surgical findings. The data for the facial canal revealed sensitivity of 66% and specificity of 84%. For semicircular canal fistula. in 59 (97%) of the 61 patients, the HRCT image-based assessment and the surgical findings coincided. The image-based assessment in the remaining two patients, who both had massive cholesteatoma, was false-positive. HRCT is useful in the diagnosis of facial canal dehiscence and labyrinthine fistula, but its limitations should also be recognized. 12 refs., 3 figs., 6 tabs.

  4. Forming Simulation of Thick AFP Laminates and Comparison with Live CT Imaging

    NASA Astrophysics Data System (ADS)

    Leutz, Daniel; Vermilyea, Mark; Bel, Sylvain; Hinterhölzl, Roland

    2016-02-01

    Automated fiber placement (AFP) process can be used to manufacture laminates by laying up unidirectional slit tapes along a desired path and placing multiple layers on top of each other. Usually, the slit tapes are placed direct onto the tooling to attain the final part geometry. Alternatively, the laminate can be built up on a planar substrate and can be subsequently formed into the final shape. This kind of processing allows manufacturing highly curved parts, which may not be possible with the direct placement. In the present work a forming simulation of thick AFP laminates is developed to predict the tapes' orientations and delamination as well as transverse tape spread-ups and separations during the forming process. The simulation model is built up through the material characterization experiments. Validation is performed comparing the results of the simulation vs. the experimental forming on two generic geometries. An optical inspection is made on the external layers of the laminates. In a second step, live computer tomography (CT) scans are used to inspect the tapes within an AFP laminate during forming of an L- and a Z-flange. Tapes re-orientation, gaps and tapes widening are observed experimentally and compared to the simulation results. The simulation is capable to predict the tows orientation and provides indicators concerning the tows spread-up and separation.

  5. Forming Simulation of Thick AFP Laminates and Comparison with Live CT Imaging

    NASA Astrophysics Data System (ADS)

    Leutz, Daniel; Vermilyea, Mark; Bel, Sylvain; Hinterhölzl, Roland

    2016-08-01

    Automated fiber placement (AFP) process can be used to manufacture laminates by laying up unidirectional slit tapes along a desired path and placing multiple layers on top of each other. Usually, the slit tapes are placed direct onto the tooling to attain the final part geometry. Alternatively, the laminate can be built up on a planar substrate and can be subsequently formed into the final shape. This kind of processing allows manufacturing highly curved parts, which may not be possible with the direct placement. In the present work a forming simulation of thick AFP laminates is developed to predict the tapes' orientations and delamination as well as transverse tape spread-ups and separations during the forming process. The simulation model is built up through the material characterization experiments. Validation is performed comparing the results of the simulation vs. the experimental forming on two generic geometries. An optical inspection is made on the external layers of the laminates. In a second step, live computer tomography (CT) scans are used to inspect the tapes within an AFP laminate during forming of an L- and a Z-flange. Tapes re-orientation, gaps and tapes widening are observed experimentally and compared to the simulation results. The simulation is capable to predict the tows orientation and provides indicators concerning the tows spread-up and separation.

  6. Pulmonary Thermal Ablation: Comparison of Radiofrequency and Microwave Devices by Using Gross Pathologic and CT Findings in a Swine Model

    PubMed Central

    Brace, Christopher L.; Hinshaw, J. Louis; Laeseke, Paul F.; Sampson, Lisa A.; Lee, Fred T.

    2009-01-01

    Purpose: To compare the performance of equivalently sized radiofrequency and microwave ablation applicators in a normal porcine lung model. Materials and Methods: All experiments were approved by an institutional animal care and use committee. A total of 18 ablations were performed in vivo in normal porcine lungs. By using computed tomographic (CT) fluoroscopic guidance, a 17-gauge cooled triaxial microwave antenna (n = 9) and a 17-gauge cooled radiofrequency (RF) electrode (n = 9) were placed percutaneously. Ablations were performed for 10 minutes by using either 125 W of microwave power or 200 W of RF power delivered with an impedance-based pulsing algorithm. CT images were acquired every minute during ablation to monitor growth. Animals were sacrificed after the procedure. Ablation zones were then excised and sectioned transverse to the applicator in 5-mm increments. Minimum and maximum diameter, cross-sectional area, length, and circularity were measured from gross specimens and CT images. Comparisons of each measurement were performed by using a mixed-effects model; P < .05 was considered to indicate a significant difference. Results: Mean diameter (3.32 cm ± 0.19 [standard deviation] vs 2.70 cm ± 0.23, P < .001) was 25% larger with microwave ablation and mean cross-sectional area (8.25 cm2 ± 0.92 vs 5.45 cm2 ± 1.14, P < .001) was 50% larger with microwave ablation, compared with RF ablation. With microwave ablation, the zones of ablation were also significantly more circular in cross section (mean circularity, 0.90 ± 0.06 vs 0.82 ± 0.09; P < .05). One small pneumothorax was noted during RF ablation but stabilized without intervention. Conclusion: Microwave ablation with a 17-gauge high-power triaxial antenna creates larger and more circular zones of ablation than does a similarly sized RF applicator in a preclinical animal model. Microwave ablation may be a more effective treatment of lung tumors. © RSNA, 2009 PMID:19336667

  7. Comparison of 68Ga-DOTANOC PET/CT and contrast-enhanced CT in localisation of tumours in ectopic ACTH syndrome

    PubMed Central

    Jadhav, Swati S; Lila, Anurag R; Kasaliwal, Rajeev; Khare, Shruti; Yerawar, Chaitanya G; Hira, Priya; Phadke, Uday; Shah, Hina; Lele, Vikram R; Malhotra, Gaurav; Bandgar, Tushar; Shah, Nalini S

    2016-01-01

    Background Localising ectopic adrenocorticotrophic hormone (ACTH) syndrome (EAS) tumour source is challenging. Somatostatin receptor-based PET imaging has shown promising results, but the data is limited to case reports and small case series. We reviewed here the performance of 68Ga-DOTANOC positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced CT (CECT) in our cohort of 12 consecutive EAS patients. Materials and methods Retrospective data analysis of 12 consecutive patients of EAS presenting to a single tertiary care centre in a period between January 2013 and December 2014 was done. CECT and 68Ga-DOTANOC PET/CT were reported (blinded) by an experienced radiologist and a nuclear medicine physician, respectively. The performance of CECT and 68Ga-DOTANOC PET/CT was compared. Results Tumours could be localised in 11 out of 12 patients at initial presentation (overt cases), whereas in one patient, tumour remained occult. Thirteen lesions were identified in 11 patients as EAS source (true positives). CECT localised 12 out of these 13 lesions (sensitivity 92.3%) and identified five false-positive lesions (positive predictive value (PPV) 70.5%). Compared with false-positive lesions, true-positive lesions had greater mean contrast enhancement at 60s (33.2 vs 5.6 Hounsfield units (HU)). 68Ga-DOTANOC PET/CT was able to identify 9 out of 13 lesions (sensitivity 69.2%) and reported no false-positive lesions (PPV 100%). Conclusion CECT remains the first-line investigation in localisation of EAS. The contrast enhancement pattern on CECT can further aid in characterisation of the lesions. 68Ga-DOTANOC PET/CT can be added to CECT, to enhance positive prediction of the suggestive lesions. PMID:27006371

  8. Comparison of (18)F-FDG PET/CT and (68)Ga-DOTATATE PET/CT imaging in metastasized Merkel cell carcinoma.

    PubMed

    Epstude, Maximilian; Tornquist, Katharina; Riklin, Christian; di Lenardo, Francesca; Winterhalder, Ralph; Hug, Urs; Strobel, Klaus

    2013-04-01

    Merkel cell carcinoma (MCC) is a rare but very aggressive neuroendocrine tumor of the skin in elderly patients with higher mortality compared with melanoma. No evidence-based standardized chemotherapy exists for metastasized patients.We report the case of an 87-year-old patient with the history of resection of a large MCC of the parietal scalp planned for radiotherapy and staged with FDG PET/CT showing disseminated distant metastases. Ga-DOTATATE PET/CT revealed more extensive tumor load compared with FDG, and due to the intensive expression of somatostatin receptors the patient qualified for Y DOTATOC therapy. PMID:23429397

  9. Ex vivo comparison of Galileos cone beam CT and intraoral radiographs in detecting occlusal caries

    PubMed Central

    Rathore, S; Tyndall, D; Wright, JT; Everett, E

    2012-01-01

    Objective The aim of this study was to compare the accuracy of cone beam CT (CBCT) with intraoral radiographs for detection of occlusal caries. Methods A set of 60 extracted teeth were imaged using a Sirona Galileos CBCT system (Sirona Dental Systems, Bensheim, Germany) and an intraoral Planmeca® system (Planmeca OY, Helsinki, Finland). Six observers looked at both modalities and used a five-point confidence scale to evaluate presence or absence of occlusal caries. Histology was used as the gold standard. Receiver operating characteristic analysis and weighted kappa statistics were used for statistical analysis. Differences in the area under the curve (AUC) values between observers and modalities were analysed using analysis of variance (ANOVA). Differences in sensitivity and specificity were analysed using the Wilcoxon test. Interobserver and intraobserver reliability was assessed by weighted kappa scores. Results The mean value and standard deviation of AUC was 0.719 ± 0.038 for CBCT and 0.649 ± 0.062 for the intraoral radiographs. The ANOVA results demonstrated that there was no significant difference between the modalities and the observers. The interobserver kappa for pairs of observers ranged from fair to substantial for bitewings (0.244–0.543) and CBCT (0.152–0.401). Four out of six observers reported higher sensitivity but lower specificity with CBCT. The Wilcoxon exact p-value showed no difference in sensitivity (0.175) or specificity (0.573) between the two modalities. Conclusion Based on the results we conclude that the Sirona CBCT unit cannot be used for the sole purpose of looking at occlusal caries. PMID:22184471

  10. Comparison of demons deformable registration-based methods for texture analysis of serial thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Cunliffe, Alexandra R.; Al-Hallaq, Hania A.; Fei, Xianhan M.; Tuohy, Rachel E.; Armato, Samuel G.

    2013-02-01

    To determine how 19 image texture features may be altered by three image registration methods, "normal" baseline and follow-up computed tomography (CT) scans from 27 patients were analyzed. Nineteen texture feature values were calculated in over 1,000 32x32-pixel regions of interest (ROIs) randomly placed in each baseline scan. All three methods used demons registration to map baseline scan ROIs to anatomically matched locations in the corresponding transformed follow-up scan. For the first method, the follow-up scan transformation was subsampled to achieve a voxel size identical to that of the baseline scan. For the second method, the follow-up scan was transformed through affine registration to achieve global alignment with the baseline scan. For the third method, the follow-up scan was directly deformed to the baseline scan using demons deformable registration. Feature values in matched ROIs were compared using Bland- Altman 95% limits of agreement. For each feature, the range spanned by the 95% limits was normalized to the mean feature value to obtain the normalized range of agreement, nRoA. Wilcoxon signed-rank tests were used to compare nRoA values across features for the three methods. Significance for individual tests was adjusted using the Bonferroni method. nRoA was significantly smaller for affine-registered scans than for the resampled scans (p=0.003), indicating lower feature value variability between baseline and follow-up scan ROIs using this method. For both of these methods, however, nRoA was significantly higher than when feature values were calculated directly on demons-deformed followup scans (p<0.001). Across features and methods, nRoA values remained below 26%.

  11. Comparison of Partial Volume Effects in Arterial and Venous Contrast Curves in CT Brain Perfusion Imaging

    PubMed Central

    Riordan, Alan J.; Bennink, Edwin; Dankbaar, Jan Willem; Viergever, Max A.; Velthuis, Birgitta K.; Smit, Ewoud J.; de Jong, Hugo W. A. M.

    2014-01-01

    Purpose In brain CT perfusion (CTP), the arterial contrast bolus is scaled to have the same area under the curve (AUC) as the venous outflow to correct for partial volume effects (PVE). This scaling is based on the assumption that large veins are unaffected by PVE. Measurement of the internal carotid artery (ICA), usually unaffected by PVE due to its large diameter, may avoid the need for partial volume correction. The aims of this work are to examine i) the assumptions behind PVE correction and ii) the potential of selecting the ICA obviating correction for PVE. Methods The AUC of the ICA and sagittal sinus were measured in CTP datasets from 52 patients. The AUCs were determined by i) using commercial CTP software based on a Gaussian curve-fitting to the time attenuation curve, and ii) by simple integration of the time attenuation curve over a time interval. In addition, frames acquired up to 3 minutes after first bolus passage were used to examine the ratio of arterial and venous enhancement. The impact of selecting the ICA without PVE correction was illustrated by reporting cerebral blood volume (CBV) measurements. Results In 49 of 52 patients, the AUC of the ICA was significantly larger than that of the sagittal sinus (p = 0.017). Measured after the first pass bolus, contrast enhancement remained 50% higher in the ICA just after the first pass bolus, and 30% higher 3 minutes later. CBV measurements were significantly lowered when the ICA was used without PVE correction. Conclusions Contradicting the assumptions underlying PVE correction, contrast in the ICA was significantly higher than in the sagittal sinus, even 3 minutes after the first pass of the contrast bolus. PVE correction might lead to overestimation of CBV if the CBV is calculated using the AUC of the time attenuation curves. PMID:24858308

  12. Dose measurements for dental cone-beam CT: a comparison with MSCT and panoramic imaging.

    PubMed

    Deman, P; Atwal, P; Duzenli, C; Thakur, Y; Ford, N L

    2014-06-21

    To date there is a lack of published information on appropriate methods to determine patient doses from dental cone-beam computed tomography (CBCT) equipment. The goal of this study is to apply and extend the methods recommended in the American Association of Physicists in Medicine (AAPM) Report 111 for CBCT equipment to characterize dose and effective dose for a range of dental imaging equipment. A protocol derived from the one proposed by Dixon et al (2010 Technical Report 111, American Association of Physicist in Medicine, MD, USA), was applied to dose measurements of multi-slice CT, dental CBCT (small and large fields of view (FOV)) and a dental panoramic system. The computed tomography dose index protocol was also performed on the MSCT to compare both methods. The dose distributions in a cylindrical polymethyl methacrylate phantom were characterized using a thimble ionization chamber and Gafchromic™ film (beam profiles). Gafchromic™ films were used to measure the dose distribution in an anthropomorphic phantom. A method was proposed to extend dose estimates to planes superior and inferior to the central plane. The dose normalized to 100 mAs measured in the center of the phantom for the large FOV dental CBCT (11.4 mGy/100 mAs) is two times lower than that of MSCT (20.7 mGy/100 mAs) for the same FOV, but approximately 15 times higher than for a panoramic system (0.6 mGy/100 mAs). The effective dose per scan (in clinical conditions) found for the dental CBCT are 167.60 ± 3.62, 61.30 ± 3.88 and 92.86 ± 7.76 mSv for the Kodak 9000 (fixed scan length of 3.7 cm), and the iCAT Next Generation for 6 cm and 13 cm scan lengths respectively. The method to extend the dose estimates from the central slice to superior and inferior slices indicates a good agreement between theory and measurement. The Gafchromic™ films provided useful beam profile data and 2D distributions of dose in phantom. PMID:24862349

  13. Dose measurements for dental cone-beam CT: a comparison with MSCT and panoramic imaging

    NASA Astrophysics Data System (ADS)

    Deman, P.; Atwal, P.; Duzenli, C.; Thakur, Y.; Ford, N. L.

    2014-06-01

    To date there is a lack of published information on appropriate methods to determine patient doses from dental cone-beam computed tomography (CBCT) equipment. The goal of this study is to apply and extend the methods recommended in the American Association of Physicists in Medicine (AAPM) Report 111 for CBCT equipment to characterize dose and effective dose for a range of dental imaging equipment. A protocol derived from the one proposed by Dixon et al (2010 Technical Report 111, American Association of Physicist in Medicine, MD, USA), was applied to dose measurements of multi-slice CT, dental CBCT (small and large fields of view (FOV)) and a dental panoramic system. The computed tomography dose index protocol was also performed on the MSCT to compare both methods. The dose distributions in a cylindrical polymethyl methacrylate phantom were characterized using a thimble ionization chamber and Gafchromic™ film (beam profiles). Gafchromic™ films were used to measure the dose distribution in an anthropomorphic phantom. A method was proposed to extend dose estimates to planes superior and inferior to the central plane. The dose normalized to 100 mAs measured in the center of the phantom for the large FOV dental CBCT (11.4 mGy/100 mAs) is two times lower than that of MSCT (20.7 mGy/100 mAs) for the same FOV, but approximately 15 times higher than for a panoramic system (0.6 mGy/100 mAs). The effective dose per scan (in clinical conditions) found for the dental CBCT are 167.60 ± 3.62, 61.30 ± 3.88 and 92.86 ± 7.76 mSv for the Kodak 9000 (fixed scan length of 3.7 cm), and the iCAT Next Generation for 6 cm and 13 cm scan lengths respectively. The method to extend the dose estimates from the central slice to superior and inferior slices indicates a good agreement between theory and measurement. The Gafchromic™ films provided useful beam profile data and 2D distributions of dose in phantom.

  14. Comparison of CLASS and ITK-SNAP in segmentation of urinary bladder in CT urography

    NASA Astrophysics Data System (ADS)

    Cha, Kenny; Hadjiiski, Lubomir; Chan, Heang-Ping; Caoili, Elaine M.; Cohan, Richard H.; Zhou, Chuan

    2014-03-01

    We are developing a computerized method for bladder segmentation in CT urography (CTU) for computeraided diagnosis of bladder cancer. We have developed a Conjoint Level set Analysis and Segmentation System (CLASS) consisting of four stages: preprocessing and initial segmentation, 3D and 2D level set segmentation, and post-processing. In case the bladder contains regions filled with intravenous (IV) contrast and without contrast, CLASS segments the noncontrast (NC) region and the contrast (C) filled region separately and conjoins the contours. In this study, we compared the performance of CLASS to ITK-SNAP 2.4, which is a publicly available software application for segmentation of structures in 3D medical images. ITK-SNAP performs segmentation by using the edge-based level set on preprocessed images. The level set were initialized by manually placing a sphere at the boundary between the C and NC parts of the bladders with C and NC regions, and in the middle of the bladders that had only C or NC region. Level set parameters and the number of iterations were chosen after experimentation with bladder cases. Segmentation performances were compared using 30 randomly selected bladders. 3D hand-segmented contours were obtained as reference standard, and computerized segmentation accuracy was evaluated in terms of the average volume intersection %, average % volume error, average absolute % volume error, average minimum distance, and average Jaccard index. For CLASS, the values for these performance metrics were 79.0±8.2%, 16.1±16.3%, 19.9±11.1%, 3.5±1.3 mm, 75.7±8.4%, respectively. For ITK-SNAP, the corresponding values were 78.8±8.2%, 8.3±33.1%, 24.2±23.7%, 5.2±2.6 mm, 71.0±15.4%, respectively. CLASS on average performed better and exhibited less variations than ITK-SNAP for bladder segmentation.

  15. Objective Volumetric Comparison of Room Air versus Carbon Dioxide for Colonic Distention at Screening CT Colonography

    PubMed Central

    Patrick, James L.; Bakke, Joshua R.; Bannas, Peter; Kim, David H.; Lubner, Meghan G.; Pickhardt, Perry J.

    2014-01-01

    Purpose To objectively compare colonic distention at CT colonography (CTC) achieved with manual room air versus automated low-pressure carbon dioxide using a novel automated volumetric quality assessment tool. Methods Volumetric analysis was retrospectively performed on CTC studies in 300 asymptomatic adults using an automated quality assessment tool (V3D Colon [beta version], Viatronix). Colonic distention was achieved with room air self-administered to tolerance via hand-held pump (mean number of pumps, 39 ± 32) in 150 individuals (mean age, 59 years; 98 men, 51 women) and via continuous low-pressure automated infusion of carbon dioxide in 150 individuals (mean age, 57 years; 89 men, 61 women). CTC studies in supine and prone position were assessed to determine total colonic volume (luminal gas and fluid). The colonic length along the automated centerline was also recorded to enable calculation of length-adjusted colonic volumes. Results The mean total colonic volume (± SD) for individuals receiving room air and carbon dioxide distention was 1809± 514 mL and 2223 ± 686 mL, respectively (p<0.01). The prone position was better distended in 78.7% (118/150) of cases using room air; whereas, the supine was better in 66.0% (99/150) of carbon dioxide cases (p<0.01). Using a volume threshold of 2000 ml, 49 (32.7%) of room air cases and 92 (61.3%) of CO2 cases were above this cut-off. The mean length-adjusted colonic volume (mL/cm) for the room air and carbon dioxide techniques was 9.9 ± 2.4 mL/cm and 11.6 ± 2.6 mL/cm (p<0.01). Conclusions Using automated volumetry allowed quantitative analyses of colonic volumes and objectively confirmed that continuous low-pressure carbon dioxide provides greater overall colonic distention than the manual room air technique at CTC. The supine position demonstrated better distention with carbon dioxide, whereas the prone position was better distended with the room air technique. PMID:25081924

  16. Setting up a Death Row Psychiatry Program

    PubMed Central

    2011-01-01

    Death row psychiatry contains a complex set of clinical, ethical, and legal questions. This Forensic Files column makes a case for correctional institutions starting death row programs to address these issues through uniform policies. A list of the relevant issues is provided. Specific issues discussed include death row psychiatric assessment, considering “justifiable” depression, treating for competency to be executed, and balancing boundaries between clinical and forensic work. PMID:21468293

  17. Comparison of pre/post-operative CT image volumes to preoperative digitization of partial hepatectomies: a feasibility study in surgical validation

    NASA Astrophysics Data System (ADS)

    Dumpuri, Prashanth; Clements, Logan W.; Li, Rui; Waite, Jonathan M.; Stefansic, James D.; Geller, David A.; Miga, Michael I.; Dawant, Benoit M.

    2009-02-01

    Preoperative planning combined with image-guidance has shown promise towards increasing the accuracy of liver resection procedures. The purpose of this study was to validate one such preoperative planning tool for four patients undergoing hepatic resection. Preoperative computed tomography (CT) images acquired before surgery were used to identify tumor margins and to plan the surgical approach for resection of these tumors. Surgery was then performed with intraoperative digitization data acquire by an FDA approved image-guided liver surgery system (Pathfinder Therapeutics, Inc., Nashville, TN). Within 5-7 days after surgery, post-operative CT image volumes were acquired. Registration of data within a common coordinate reference was achieved and preoperative plans were compared to the postoperative volumes. Semi-quantitative comparisons are presented in this work and preliminary results indicate that significant liver regeneration/hypertrophy in the postoperative CT images may be present post-operatively. This could challenge pre/post operative CT volume change comparisons as a means to evaluate the accuracy of preoperative surgical plans.

  18. TU-C-12A-11: Comparisons Between Cu-ATSM PET and DCE-CT Kinetic Parameters in Canine Sinonasal Tumors

    SciTech Connect

    La Fontaine, M; Bradshaw, T; Kubicek, L; Forrest, L; Jeraj, R

    2014-06-15

    Purpose: Regions of poor perfusion within tumors may be associated with higher hypoxic levels. This study aimed to test this hypothesis by comparing measurements of hypoxia from Cu-ATSM PET to vasculature kinetic parameters from DCE-CT kinetic analysis. Methods: Ten canine patients with sinonasal tumors received one Cu-ATSM PET/CT scan and three DCE-CT scans prior to treatment. Cu-ATSM PET/CT and DCE-CT scans were registered and resampled to matching voxel dimensions. Kinetic analysis was performed on DCE-CT scans and for each patient, the resulting kinetic parameter values from the three DCE-CT scans were averaged together. Cu-ATSM SUVs were spatially correlated (r{sub spatial}) on a voxel-to-voxel basis against the following DCE-CT kinetic parameters: transit time (t{sub 1}), blood flow (F), vasculature fraction (v{sub 1}), and permeability (PS). In addition, whole-tumor comparisons were performed by correlating (r{sub ROI}) the mean Cu-ATSM SUV (SUV{sub mean}) with median kinetic parameter values. Results: The spatial correlations (r{sub spatial}) were poor and ranged from -0.04 to 0.21 for all kinetic parameters. These low spatial correlations may be due to high variability in the DCE-CT kinetic parameter voxel values between scans. In our hypothesis, t{sub 1} was expected to have a positive correlation, while F was expected to have a negative correlation to hypoxia. However, in wholetumor analysis the opposite was found for both t{sub 1} (r{sub ROI} = -0.25) and F (r{sub ROI} = 0.56). PS and v{sub 1} may depict angiogenic responses to hypoxia and found positive correlations to Cu-ATSM SUV for PS (r{sub ROI} = 0.41), and v{sub 1} (r{sub ROI} = 0.57). Conclusion: Low spatial correlations were found between Cu-ATSM uptake and DCE-CT vasculature parameters, implying that poor perfusion is not associated with higher hypoxic regions. Across patients, the most hypoxic tumors tended to have higher blood flow values, which is contrary to our initial hypothesis. Funding

  19. Multi-detector row computed tomography angiography of peripheral arterial disease

    PubMed Central

    Dijkshoorn, Marcel L.; Pattynama, Peter M. T.; Myriam Hunink, M. G.

    2007-01-01

    With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD. PMID:17882427

  20. : Light Interception in Single Row, Twin Row, and Diamond Planting Patterns of Valencia Peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field study was conducted on a growers farm South of Clovis, NM in 2006 to compare light interception and radiation use efficiency in single row, twin row, and diamond planted Valencia peanuts with line quantum sensors (Apogee instruments, Logan) installed across the crop row. Data were recorded ...

  1. YIELD AND GRADE OF VALENCIA PEANUT IN SINGLE ROW, TWIN ROW, AND DIAMOND PLANTING PATTERNS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted at Wayne Baker’s farm South of Clovis in 2006 to compare single row, twin row, and diamond planting patterns in Valencia peanut on 36 inch beds. The twin row and diamond pattern treatments were planted with an experimental planter developed at the USDA-ARS National Peanut Rese...

  2. MO-E-17A-03: Monte Carlo CT Dose Calculation: A Comparison Between Experiment and Simulation Using ARCHER-CT

    SciTech Connect

    Liu, T; Du, X; Su, L; Gao, Y; Ji, W; Xu, X; Zhang, D; Shi, J; Liu, B; Kalra, M

    2014-06-15

    Purpose: To compare the CT doses derived from the experiments and GPU-based Monte Carlo (MC) simulations, using a human cadaver and ATOM phantom. Methods: The cadaver of an 88-year old male and the ATOM phantom were scanned by a GE LightSpeed Pro 16 MDCT. For the cadaver study, the Thimble chambers (Model 10×5−0.6CT and 10×6−0.6CT) were used to measure the absorbed dose in different deep and superficial organs. Whole-body scans were first performed to construct a complete image database for MC simulations. Abdomen/pelvis helical scans were then conducted using 120/100 kVps, 300 mAs and a pitch factor of 1.375:1. For the ATOM phantom study, the OSL dosimeters were used and helical scans were performed using 120 kVp and x, y, z tube current modulation (TCM). For the MC simulations, sufficient particles were run in both cases such that the statistical errors of the results by ARCHER-CT were limited to 1%. Results: For the human cadaver scan, the doses to the stomach, liver, colon, left kidney, pancreas and urinary bladder were compared. The difference between experiments and simulations was within 19% for the 120 kVp and 25% for the 100 kVp. For the ATOM phantom scan, the doses to the lung, thyroid, esophagus, heart, stomach, liver, spleen, kidneys and thymus were compared. The difference was 39.2% for the esophagus, and within 16% for all other organs. Conclusion: In this study the experimental and simulated CT doses were compared. Their difference is primarily attributed to the systematic errors of the MC simulations, including the accuracy of the bowtie filter modeling, and the algorithm to generate voxelized phantom from DICOM images. The experimental error is considered small and may arise from the dosimeters. R01 grant (R01EB015478) from National Institute of Biomedical Imaging and Bioengineering.

  3. Monte Carlo comparison of x-ray and proton CT for range calculations of proton therapy beams.

    PubMed

    Arbor, N; Dauvergne, D; Dedes, G; Létang, J M; Parodi, K; Quiñones, C T; Testa, E; Rit, S

    2015-10-01

    Proton computed tomography (CT) has been described as a solution for imaging the proton stopping power of patient tissues, therefore reducing the uncertainty of the conversion of x-ray CT images to relative stopping power (RSP) maps and its associated margins. This study aimed to investigate this assertion under the assumption of ideal detection systems. We have developed a Monte Carlo framework to assess proton CT performances for the main steps of a proton therapy treatment planning, i.e. proton or x-ray CT imaging, conversion to RSP maps based on the calibration of a tissue phantom, and proton dose simulations. Irradiations of a computational phantom with pencil beams were simulated on various anatomical sites and the proton range was assessed on the reference, the proton CT-based and the x-ray CT-based material maps. Errors on the tissue's RSP reconstructed from proton CT were found to be significantly smaller and less dependent on the tissue distribution. The imaging dose was also found to be much more uniform and conformal to the primary beam. The mean absolute deviation for range calculations based on x-ray CT varies from 0.18 to 2.01 mm depending on the localization, while it is smaller than 0.1 mm for proton CT. Under the assumption of a perfect detection system, proton range predictions based on proton CT are therefore both more accurate and more uniform than those based on x-ray CT. PMID:26378805

  4. Monte Carlo comparison of x-ray and proton CT for range calculations of proton therapy beams

    NASA Astrophysics Data System (ADS)

    Arbor, N.; Dauvergne, D.; Dedes, G.; Létang, J. M.; Parodi, K.; Quiñones, C. T.; Testa, E.; Rit, S.

    2015-10-01

    Proton computed tomography (CT) has been described as a solution for imaging the proton stopping power of patient tissues, therefore reducing the uncertainty of the conversion of x-ray CT images to relative stopping power (RSP) maps and its associated margins. This study aimed to investigate this assertion under the assumption of ideal detection systems. We have developed a Monte Carlo framework to assess proton CT performances for the main steps of a proton therapy treatment planning, i.e. proton or x-ray CT imaging, conversion to RSP maps based on the calibration of a tissue phantom, and proton dose simulations. Irradiations of a computational phantom with pencil beams were simulated on various anatomical sites and the proton range was assessed on the reference, the proton CT-based and the x-ray CT-based material maps. Errors on the tissue’s RSP reconstructed from proton CT were found to be significantly smaller and less dependent on the tissue distribution. The imaging dose was also found to be much more uniform and conformal to the primary beam. The mean absolute deviation for range calculations based on x-ray CT varies from 0.18 to 2.01 mm depending on the localization, while it is smaller than 0.1 mm for proton CT. Under the assumption of a perfect detection system, proton range predictions based on proton CT are therefore both more accurate and more uniform than those based on x-ray CT.

  5. Comparison of CT on Rails With Electronic Portal Imaging for Positioning of Prostate Cancer Patients With Implanted Fiducial Markers

    SciTech Connect

    Owen, Rebecca Kron, Tomas; Foroudi, Farshad; Milner, Alvin; Cox, Jennifer; Duchesne, Gillian; Cleeve, Laurence; Zhu Li; Cramb, Jim; Sparks, Laura; Laferlita, Marcus

    2009-07-01

    Purpose: The objective of this investigation was to measure the agreement between in-room computed tomography (CT) on rails and electronic portal image (EPI) radiography. Methods and Materials: Agreement between the location of the center of gravity (COG) of fiducial markers (FMs) on CT and EPI images was determined in phantom studies and a patient cohort. A secondary analysis between the center of volume (COV) of the prostate on CT and the COG of FMs on CT and EPI was performed. Agreement was defined as the 95% probability of a difference of {<=}3.0 mm between images. Systematic and random errors from CT and EPI are reported. Results: From 8 patients, 254 CT and EPI pairs were analyzed. FMs were localized to within 3 mm on CT and EPI images 96.9% of the time in the left-right (LR) plane, 85.8% superior-inferior (SI), and 89% anterior-posterior (AP). The differences between the COV on CT and the COG on EPI were not within 3 mm in any plane: 87.8% (LR), 64.2% (SI), and 70.9% (AP). The systematic error varied from 1.2 to 2.9 mm (SI) and 1.8-2.9 mm (AP) between the COG on EPI and COV on CT. Conclusions: Considerable differences between in-room CT and EPI exist. The phantom measurements showed slice thickness affected the accuracy of localization in the SI plane, and couch sag that occurs at the CT on rails gantry could not be totally corrected for in the AP plane. Other confounding factors are the action of rotating the couch and associated time lag between image acquisitions (prostate motion), EPI image quality, and outlining uncertainties.

  6. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    SciTech Connect

    Viswanathan, Akila N.; Gaffney, David K.; Beriwal, Sushil; Bhatia, Sudershan K.; Lee Burnett, Omer; D'Souza, David P.; Patil, Nikhilesh; Haddock, Michael G.; Jhingran, Anuja; Jones, Ellen L.; Kunos, Charles A.; Lee, Larissa J.; Mayr, Nina A.; Petersen, Ivy; Petric, Primoz; Portelance, Lorraine; Small, William; Strauss, Jonathan B.; and others

    2014-10-01

    Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

  7. On Row Rank Equal Column Rank

    ERIC Educational Resources Information Center

    Khalili, Parviz

    2009-01-01

    We will prove a well-known theorem in Linear Algebra, that is, for any "m x n" matrix the dimension of row space and column space are the same. The proof is based on the subject of "elementary matrices" and "reduced row-echelon" form of a matrix.

  8. Rows=Wildlife Corridors: An Urban Resource.

    ERIC Educational Resources Information Center

    Young, Darrell D.

    1983-01-01

    Linear strips of land associated with highways, electrical transmission lines, gas/oil pipelines (called right-of-way or ROWs) are inhibited by a variety of wildlife and offer a unique opportunity to study the wildlife in the urban setting. Types of wildlife found in and importance of ROWs are discussed. (JN)

  9. State-of-the-art in CT hardware and scan modes for cardiovascular CT

    PubMed Central

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J.; Gentry, Ralph; George, Richard T.; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm. Guy

    2013-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and the coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography (SCCT) Basic and Emerging Sciences and Technology (BEST) Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging. PMID:22551595

  10. Rowing and sculling and the older athlete.

    PubMed

    Boland, A L; Hosea, T M

    1991-04-01

    Rowing is a strenuous sport that has a significant injury rate among competitive participants. Consequently, older individuals who are anticipating beginning recreational rowing should start with a thorough physical examination by their physician. Because the back and knees are the most frequently injured areas, an orthopedic assessment of these regions is indicated in those individuals who have had previous patellofemoral or low back pain. All prospective rowers should begin with a general conditioning program that addresses lower extremity and abdominal strengthening, flexibility, and aerobic conditioning. A thorough understanding of the proper mechanics of rowing is essential to avoid potential injury. Rowing is a satisfying sport that offers excellent physical exercise and cardiovascular benefits. Older individuals should be encouraged to row, but also should be aware of the variety of injuries this sport may produce. PMID:1830245

  11. Infant Cardiac CT Angiography with 64-Slice and 256-Slice CT: Comparison of Radiation Dose and Image Quality Using a Pediatric Phantom

    PubMed Central

    Mok, Greta S. P.; Wu, Tung-Hsin

    2012-01-01

    Background The aims of this study were to investigate the image quality and radiation exposure of pediatric protocols for cardiac CT angiography (CTA) in infants under one year of age. Methodology/Principal Findings Cardiac CTA examinations were performed using an anthropomorphic phantom representing a 1-year-old child scanned with non-electrocardiogram-gated (NG), retrospectively electrocardiogram-gated helical (RGH) and prospectively electrocardiogram-gated axial (PGA) techniques in 64-slice and 256-slice CT scanners. The thermoluminescent dosimeters (TLD) were used for direct organ dose measurement, while dose-length product and effective mAs were also used to estimate the patient dose. For image quality, noise and signal-to-noise-ratio (SNR) were assessed based on regions-of-interest drawn on the reconstructed CT images, and were compared with the proposed cardiac image quantum index (CIQI). Estimated dose results were in accordant to the measured doses. The NG scan showed the best image quality in terms of noise and SNR. The PGA scan had better image quality than the RGH scan with 83.70% dose reduction. Noise and SNR were also corresponded to the proposed CIQI. Conclusions/Significance The PGA scan protocol was a good choice in balancing radiation exposure and image quality for infant cardiac CTA. We also suggested that the effective mAs and the CIQI were suitable in assessing the tradeoffs between radiation dose and image quality for cardiac CTA in infants. These results are useful for future implementation of dose reduction strategies in pediatric cardiac CTA protocols. PMID:23185380

  12. Emphysema quantification from CT scans using novel application of diaphragm curvature estimation: comparison with standard quantification methods and pulmonary function data

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.; Barr, R. Graham

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for the imaging of the anatomical basis of emphysema and quantification of the underlying disease state. Several measures have been introduced for the quantification emphysema directly from CT data; most,however, are based on the analysis of density information provided by the CT scans, which vary by scanner and can be hard to standardize across sites and time. Given that one of the anatomical variations associated with the progression of emphysema is the flatting of the diaphragm due to the loss of elasticity in the lung parenchyma, curvature analysis of the diaphragm would provide information about emphysema from CT. Therefore, we propose a new, non-density based measure of the curvature of the diaphragm that would allow for further quantification methods in a robust manner. To evaluate the new method, 24 whole-lung scans were analyzed using the ratios of the lung height and diaphragm width to diaphragm height as curvature estimates as well as using the emphysema index as comparison. Pearson correlation coefficients showed a strong trend of several of the proposed diaphragm curvature measures to have higher correlations, of up to r=0.57, with DLCO% and VA than did the emphysema index. Furthermore, we found emphysema index to have only a 0.27 correlation to the proposed measures, indicating that the proposed measures evaluate different aspects of the disease.

  13. Three-dimensional visual truth of the normal airway tree for use as a quantitative comparison to micro-CT reconstructions

    NASA Astrophysics Data System (ADS)

    Thiesse, Jacqueline; Reinhardt, Joseph M.; de Ryk, Jessica; Namati, Eman; Leinen, Jessica; Recheis, Wolfgang A.; Hoffman, Eric A.; McLennan, Geoffrey

    2005-04-01

    Mouse models are important for pulmonary research to gain insight into structure and function in normal and diseased states, thereby extending knowledge of human disease conditions. The flexibility of human disease induction into mice, due to their similar genome, along with their short gestation cycle makes mouse models highly suitable as investigative tools. Advancements in non-invasive imaging technology, with the development of micro-computed tomography (μ-CT), have aided representation of disease states in these small pulmonary system models. The generation ofμCT 3D airway reconstructions has to date provided a means to examine structural changes associated with disease. The degree of accuracy ofμCT is uncertain. Consequently, the reliability of quantitative measurements is questionable. We have developed a method of sectioning and imaging the whole mouse lung using the Large Image Microscope Array (LIMA) as the gold standard for comparison. Fixed normal mouse lungs were embedded in agarose and 250μm sections of tissue were removed while the remaining tissue block was imaged with a stereomicroscope. A complete dataset of the mouse lung was acquired in this fashion. Following planar image registration, the airways were manually segmented using an in-house built software program PASS. Amira was then used render the 3D isosurface from the segmentations. The resulting 3D model of the normal mouse airway tree developed from pathology images was then quantitatively assessed and used as the standard to compare the accuracy of structural measurements obtained from μ-CT.

  14. Does management intensity in inter rows effect soil physical properties in Austrian and Romanian vineyards?

    NASA Astrophysics Data System (ADS)

    Bauer, Thomas; Strauss, Peter; Stiper, Katrin; Klipa, Vladimir; Popescu, Daniela; Winter, Silvia; Zaller, Johann G.

    2016-04-01

    Successful viticulture is mainly influenced by soil and climate. The availability of water during the growing season highly influences wine quality and quantity. To protect soil from being eroded most of the winegrowers keep the inter row zones of the vineyards green. Greening also helps to provide water-stress to the grapes for harvesting high quality wines. However, these greening strategies concerning the intensity of inter row management differ from farm to farm and are mainly based on personal experience of the winegrowers. However to what extent different inter row management practices affect soil physical properties are not clearly understood yet. To measure possible effects of inter row management in vineyards on soil physical parameters we selected paired vineyards with different inter row management in Austria and Romania. In total more than 7000 soil analysis were conducted for saturated and unsaturated hydraulic conductivity, soil water retention, water stable aggregates, total organic carbon, cation exchange capacity, potassium, phosphorous, soil texture, bulk density and water infiltration. The comparison between high intensity management with at least one soil disturbance per year, medium intensity with one soil disturbance every second inter row per year and low intensity management with no soil disturbance since at least 5 years indicates that investigated soil physical properties did not improve for the upper soil layer (3-8cm). This is in contrast to general perceptions of improved soil physical properties due to low intensity of inter row management, i.e. permanent vegetated inter rows. This may be attributed to long term and high frequency mechanical stress by agricultural machinery in inter rows.

  15. SU-E-P-11: Comparison of Image Quality and Radiation Dose Between Different Scanner System in Routine Abdomen CT

    SciTech Connect

    Liao, S; Wang, Y; Weng, H

    2015-06-15

    Purpose To evaluate image quality and radiation dose of routine abdomen computed tomography exam with the automatic current modulation technique (ATCM) performed in two different brand 64-slice CT scanners in our site. Materials and Methods A retrospective review of routine abdomen CT exam performed with two scanners; scanner A and scanner B in our site. To calculate standard deviation of the portal hepatic level with a region of interest of 12.5 mm x 12.5mm represented to the image noise. The radiation dose was obtained from CT DICOM image information. Using Computed tomography dose index volume (CTDIv) to represented CT radiation dose. The patient data in this study were with normal weight (about 65–75 Kg). Results The standard deviation of Scanner A was smaller than scanner B, the scanner A might with better image quality than scanner B. On the other hand, the radiation dose of scanner A was higher than scanner B(about higher 50–60%) with ATCM. Both of them, the radiation dose was under diagnostic reference level. Conclusion The ATCM systems in modern CT scanners can contribute a significant reduction in radiation dose to the patient. But the reduction by ATCM systems from different CT scanner manufacturers has slightly variation. Whatever CT scanner we use, it is necessary to find the acceptable threshold of image quality with the minimum possible radiation exposure to the patient in agreement with the ALARA principle.

  16. Comparison of 18F-FDG PET/CT and PET/MRI in patients with multiple myeloma

    PubMed Central

    Sachpekidis, Christos; Hillengass, Jens; Goldschmidt, Hartmut; Mosebach, Jennifer; Pan, Leyun; Schlemmer, Heinz-Peter; Haberkorn, Uwe; Dimitrakopoulou-Strauss, Antonia

    2015-01-01

    PET/MRI represents a promising hybrid imaging modality with several potential clinical applications. Although PET/MRI seems highly attractive in the diagnostic approach of multiple myeloma (MM), its role has not yet been evaluated. The aims of this prospective study are to evaluate the feasibility of 18F-FDG PET/MRI in detection of MM lesions, and to investigate the reproducibility of bone marrow lesions detection and quantitative data of 18F-FDG uptake between the functional (PET) component of PET/CT and PET/MRI in MM patients. The study includes 30 MM patients. All patients initially underwent 18F-FDG PET/CT (60 min p.i.), followed by PET/MRI (120 min p.i.). PET/CT and PET/MRI data were assessed and compared based on qualitative (lesion detection) and quantitative (SUV) evaluation. The hybrid PET/MRI system provided good image quality in all cases without artefacts. PET/MRI identified 65 of the 69 lesions, which were detectable with PET/CT (94.2%). Quantitative PET evaluations showed the following mean values in MM lesions: SUVaverage=5.5 and SUVmax=7.9 for PET/CT; SUVaverage=3.9 and SUVmax=5.8 for PET/MRI. Both SUVaverage and SUVmax were significantly higher on PET/CT than on PET/MRI. Spearman correlation analysis demonstrated a strong correlation between both lesional SUVaverage (r=0.744) and lesional SUVmax (r=0.855) values derived from PET/CT and PET/MRI. Regarding detection of myeloma skeletal lesions, PET/MRI exhibited equivalent performance to PET/CT. In terms of tracer uptake quantitation, a significant correlation between the two techniques was demonstrated, despite the statistically significant differences in lesional SUVs between PET/CT and PET/MRI. PMID:26550538

  17. Comparison of Scientific Calipers and Computer-Enabled CT Review for the Measurement of Skull Base and Craniomaxillofacial Dimensions

    PubMed Central

    Citardi, Martin J.; Herrmann, Brian; Hollenbeak, Chris S.; Stack, Brendan C.; Cooper, Margaret; Bucholz, Richard D.

    2001-01-01

    Traditionally, cadaveric studies and plain-film cephalometrics provided information about craniomaxillofacial proportions and measurements; however, advances in computer technology now permit software-based review of computed tomography (CT)-based models. Distances between standardized anatomic points were measured on five dried human skulls with standard scientific calipers (Geneva Gauge, Albany, NY) and through computer workstation (StealthStation 2.6.4, Medtronic Surgical Navigation Technology, Louisville, CO) review of corresponding CT scans. Differences in measurements between the caliper and CT model were not statistically significant for each parameter. Measurements obtained by computer workstation CT review of the cranial skull base are an accurate representation of actual bony anatomy. Such information has important implications for surgical planning and clinical research. ImagesFigure 1Figure 2Figure 3 PMID:17167599

  18. Detection of abdominal aortic graft infection: comparison of CT and In-labeled white blood cell scans

    SciTech Connect

    Mark, A.S.; McCarthy, S.M.; Moss, A.A.; Price, D.

    1985-02-01

    Aortic graft infections are a rare but potentially lethal complication of aortic graft surgery. The diagnosis and assessment of the extent of a graft infection is difficult on clinical grounds. A prospective study compared CT and indium-labeled white blood cell (In-WBC) scans in the diagnosis of aortic graft infection. Five patients with aortic graft infection and three patients without aortic graft infection were studied by both methods. CT correctly detected the retroperitoneal extension of the infection in three patients with groin infection; In-WBC scans diagnosed the extension only in one patient. Both CT and In-WBC were positive in two patients with aortic graft infection but no groin infection. Both studies were negative in the three patients without evidence of aortic graft infection. The study suggests that CT is more sensitive than In-WBC in evaluating the extent of aortic graft infection and should be the imaging method of choice.

  19. Region of interest (ROI) computed tomography (CT): Comparison with full field of view (FFOV) and truncated CT for a human head phantom

    PubMed Central

    Chityala, R.; Hoffmann, K. R.; Rudin, S.; Bednarek, D. R.

    2011-01-01

    Cone-beam CT reconstruction can be performed at lower integral dose, by using a non-uniform beam filter between the x-ray source and the patient to obtain good image quality within an ROI with minimal artifacts. To evaluate the method, a human head phantom was placed on a rotary stage. Cone-beam projection images of the phantom were obtained with and without an ROI filter (dose reduction factor ~7). A mapping function was established to equalize the intensity outside the ROI (to compensate for the attenuation by the filter) to the intensity inside by assuming that those features lying both inside and outside very close to the edge of the ROI are the same. Reconstructed images were obtained using equalized projection images for 2 cases: one in which the outside region was smoothed using an averaging filter and the other with no smoothing outside. In addition, a third case was simulated by calculating the average pixel value inside the ROI for each image and assigning this value to all pixels outside the ROI for that image. The images were then back projected using a Feldkamp algorithm. We found that the three cases yield results inside the ROI comparable to those obtained using FFOV projections. In addition, the ROI filter reconstruction with smoothing provides image information outside the ROI comparable to the FFOV reconstruction. CT using an ROI filter provides a means to reconstruct reliable 3D for a volume of interest with greatly reduced integral dose compared to FFOV projections and with minimal artifacts. PMID:21311728

  20. Diagnosis of Sturge-Weber syndrome: comparison of the efficacy of CT and MR imaging in 14 cases.

    PubMed

    Martí-Bonmatí, L; Menor, F; Poyatos, C; Cortina, H

    1992-04-01

    Sturge-Weber syndrome is a neurocutaneous syndrome that includes facial and leptomeningeal angiomas. Imaging findings include cerebral lobar atrophy, brain calcifications, choroid plexus enlargement, cranial diploë prominence, and venous abnormalities. We compared the efficacy of CT and MR imaging in making the diagnosis in 14 consecutive patients. CT, with and without contrast enhancement, was performed in all patients, and 11 of the 14 had MR imaging (eight before and after administration of IV gadopentetate dimeglumine). MR imaging was better than CT in showing the extent and degree of brain parenchymal atrophy, the presumed ischemic changes affecting the gray and white matter, and the cranial diploetic prominence on the affected side. MR imaging after contrast administration permitted a better evaluation of the extent and patency of the leptomeningeal angiomatous malformation and the parenchymal venous anomalies. CT was better than MR imaging in showing the presence and extent of cortical calcifications. Enhanced CT and MR imaging were equal in evaluating the prominence of the ipsilateral choroid plexus. Our experience indicates that contrast-enhanced MR imaging is the method of choice in the diagnosis of Sturge-Weber syndrome. Unenhanced CT should be used only if MR findings are normal, to exclude the presence of intracranial calcifications. PMID:1546607

  1. 18F-FDG PET/CT Role in Staging of Gastric Carcinomas: Comparison with Conventional Contrast Enhancement Computed Tomography

    PubMed Central

    Altini, Corinna; Niccoli Asabella, Artor; Di Palo, Alessandra; Fanelli, Margherita; Ferrari, Cristina; Moschetta, Marco; Rubini, Giuseppe

    2015-01-01

    Abstract The purpose of the report was to evaluate the role of fluorine-18 fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in staging gastric cancer comparing it with contrast enhancement computed tomography (CECT). This retrospective study included 45 patients who underwent performed whole body CECT and 18F-FDG PET/CT before any treatment. We calculated CECT and 18F-FDG PET/CT sensitivity, specificity, accuracy, positive and negative predictive values (PPV and NPV) for gastric, lymphnode, and distant localizations; furthermore, we compared the 2 techniques by McNemar test. The role of 18F-FDG PET/CT semiquantitative parameters in relation to histotype, grading, and site of gastric lesions were evaluated by ANOVA test. Sensitivity, specificity, accuracy, PPV and NPV of CECT, and 18F-FDG PET/CT for gastric lesion were, respectively, 92.11%, 57.14%, 86.66%, 92.11%, 57.14% and 81.58%, 85.71%, 82.22%, 96.88%, 46.15%. No differences were identified between the 2 techniques about sensitivity and specificity. No statistical differences were observed between PET parameters and histotype, grading, and site of gastric lesion. The results of CECT and 18F-FDG PET/CT about lymphnode involvement were 70.83%, 61.90%, 66.66%, 68%, 65% and 58.33%, 95.24%, 75.55%, 93.33%, 66.67%. The results of CECT and 18F-FDG PET/CT about distant metastases were 80%, 62.86%, 66.66%, 38.10%, 91.67% and 60%, 88.57%, 82.22%, 60%, 88.57%. 18FDG PET/CT specificity was significantly higher both for lymphnode and distant metastases. The 18F-FDG PET/CT is a useful tool for the evaluation of gastric carcinoma to detect primary lesion, lymphnode, and distant metastases using 1 single image whole-body technique. Integration of CECT with 18F-FDG PET/CT permits a more valid staging in these patients. PMID:25997066

  2. Comparison of an alternative and existing binning methods to reduce the acquisition duration of 4D PET/CT

    SciTech Connect

    Didierlaurent, David Ribes, Sophie; Caselles, Olivier; Jaudet, Cyril; Dierickx, Lawrence O.; Zerdoud, Slimane; Brillouet, Severine; Weits, Kathleen; Batatia, Hadj; Courbon, Frédéric

    2014-11-01

    Purpose: Respiratory motion is a source of artifacts that reduce image quality in PET. Four dimensional (4D) PET/CT is one approach to overcome this problem. Existing techniques to limiting the effects of respiratory motions are based on prospective phase binning which requires a long acquisition duration (15–25 min). This time is uncomfortable for the patients and limits the clinical exploitation of 4D PET/CT. In this work, the authors evaluated an existing method and an alternative retrospective binning method to reduce the acquisition duration of 4D PET/CT. Methods: The authors studied an existing mixed-amplitude binning (MAB) method and an alternative binning method by mixed-phases (MPhB). Before implementing MPhB, they analyzed the regularity of the breathing patterns in patients. They studied the breathing signal drift and missing CT slices that could be challenging for implementing MAB. They compared the performance of MAB and MPhB with current binning methods to measure the maximum uptake, internal volume, and maximal range of tumor motion. Results: MPhB can be implemented depending on an optimal phase (in average, the exhalation peak phase −4.1% of the entire breathing cycle duration). Signal drift of patients was in average 35% relative to the breathing amplitude. Even after correcting this drift, MAB was feasible in 4D CT for only 64% of patients. No significant differences appeared between the different binning methods to measure the maximum uptake, internal volume, and maximal range of tumor motion. The authors also determined the inaccuracies of MAB and MPhB to measure the maximum amplitude of tumor motion with three bins (less than 3 mm for movement inferior to 12 mm, up to 6.4 mm for a 21 mm movement). Conclusions: The authors proposed an alternative binning method by mixed-phase binning that halves the acquisition duration of 4D PET/CT. Mixed-amplitude binning was challenging because of signal drift and missing CT slices. They showed that more

  3. SU-E-I-84: Accuracy Comparison of Multi-Modality Image-Based Volumes of Rodent Solid Tumors Using In-Air Micro-CT Image Volume

    SciTech Connect

    Lee, Y; Fullerton, G; Goins, B

    2015-06-15

    Purpose: Tumor volume is considered as a better predictor for therapy response monitoring and tumor staging over Response Evaluation Criteria In Solid Tumors (RECIST) or World Health Organization (WHO) criteria. In this study, the accuracy of subcutaneous rodent tumor volumes using preclinical magnetic resonance imaging (MRI), micro-computed tomography (micro-CT) and ultrasound (US) equipment and with an external caliper was compared using in-air micro-CT image volume of excised tumors determined as reference tumor volume in our prior study. Methods: MR, US and micro-CT images of subcutaneous SCC4 head and neck tumor xenografts were acquired 4, 6, 9, 11 and 13 days after tumor cell inoculation. Before MR and US scans, caliper measurements were made. After tumors were excised, in-air micro-CT imaging and ex vivo caliper measurements were performed. Tumor volumes were calculated using formula V = (π/6)*a*b*c where a, b and c are the maximum diameters in three perpendicular dimensions determined by the three image modalities and caliper, and compared with reference tumor volume by linear regression analysis as well as Bland-Altman plots. A one-way Analysis of Variance (ANOVA) test was also performed to compare volumes among caliper measurements. Results: The correlation coefficients (R2) of the regression lines for tumor volumes measured by the three imaging modalities and caliper were 0.9939, 0.9669, 0.9806, 0.9274, 0.9619 and 0.9819 for MRI, US and micro-CT, caliperbeforeMRI, caliperbeforeUS and ex vivo caliper respectively. In Bland-Altman plots, the average of tumor volume difference from reference tumor volume (bias) was significant for caliper and micro- CT, but not for MRI and US. Comparison of caliper measurements showed a significant difference (p < 0.05). Conclusion: Using the in-air micro-CT image volume, tumor volume measured by MRI was the most accurate among the three imaging modalities. In vivo caliper volume measurements showed unreliability while ex

  4. Automated segmentation and tracking of coronary arteries in cardiac CT scans: comparison of performance with a clinically used commercial software

    NASA Astrophysics Data System (ADS)

    Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Patel, Smita; Hadjiiski, Lubomir M.; Sahiner, Berkman; Wei, Jun; Kazerooni, Ella A.

    2010-03-01

    Coronary CT angiography (cCTA) has been reported to be an effective means for diagnosis of coronary artery disease. We are investigating the feasibility of developing a computer-aided detection (CADe) system to assist radiologists in detection of non-calcified plaques in coronary arteries in ECG-gated cCTA scans. In this study, we developed a prototype vessel segmentation and tracking method to extract the coronary arterial trees which will define the search space for plaque detection. Vascular structures are first enhanced by 3D multi-scale filtering and analysis of the eigenvalues of Hessian matrices using a vessel enhancement response function specifically designed for coronary arteries. The enhanced vascular structures are then segmented by an EM estimation method. The segmented coronary arteries are tracked using a 3D dynamic balloon tracking (DBT) method. For this preliminary study, two starting seed points were manually identified at the origins of the left and right coronary artery (LCA and RCA). The DBT method automatically moves a sphere along the vessel whose diameter is adjusted dynamically based on the local vessel size, tracks the vessels, and identifies its branches to generate the left and right coronary arterial trees. The algorithm was applied to 20 cCTA scans that contained various degrees of coronary artery diseases. To evaluate the performance of vessel segmentation and tracking, the rendered volume of coronary arteries tracked by our algorithm was displayed on a PC, placed next to a GE Advantage workstation on which the coronary arterial trees tracked by the GE software and the original cCTA scan were displayed. Two experienced thoracic radiologists visually examined the coronary arteries on the cCTA scan and the segmented vessels to count untracked false-negative (FN) segments and false positives (FPs). The comparison was made by radiologists' visual judgment because the digital files for the segmented vessels were not accessible on the

  5. A comparison of CT- and ultrasound-based imaging to localize the prostate for external beam radiotherapy

    SciTech Connect

    McNair, Helen A. . E-mail: Helen.McNair@rmh.nhs.uk; Mangar, Stephen A.; Coffey, Jerome; Shoulders, Beverley; Hansen, Vibeke N.; Norman, Andrew; Staffurth, John; Sohaib, S. Aslam; Warrington, Alan P.; Dearnaley, David P.

    2006-07-01

    Purpose: This study assesses the accuracy of NOMOS B-mode acquisition and targeting system (BAT) compared with computed tomography (CT) in localizing the prostate. Methods and Materials: Twenty-six patients were CT scanned, and the prostate was localized by 3 observers using the BAT system. The BAT couch shift measurements were compared with the CT localization. Six of the patients had gold markers present in the prostate, and the prostate movement determined by BAT was compared with the movement determined by the gold markers. Results: Using the BAT system, the 3 observers determined the prostate position to be a mean of 1-5 mm over all directions with respect to the CT. The proportion of readings with a difference >3 mm between the observers was in the range of 25% to 44%. The prostate movement based on gold markers was an average of 3-5 mm different from that measured by BAT. The literature assessing the accuracy and reproducibility on BAT is summarized and compared with our findings. Conclusions: We have found that there are systematic differences between the BAT-defined prostate position compared with that estimated on CT using gold grain marker seeds.

  6. Developing Formulas by Skipping Rows in Pascal's Triangle

    ERIC Educational Resources Information Center

    Buonpastore, Robert J.; Osler, Thomas J.

    2007-01-01

    A table showing the first thirteen rows of Pascal's triangle, where the rows are, as usual numbered from 0 to 12 is presented. The entries in the table are called binomial coefficients. In this note, the authors systematically delete rows from Pascal's triangle and, by trial and error, try to find a formula that allows them to add new rows to the…

  7. Characterization of Genome-Wide Variation in Four-Row Wax, a Waxy Maize Landrace with a Reduced Kernel Row Phenotype

    PubMed Central

    Liu, Hanmei; Wang, Xuewen; Wei, Bin; Wang, Yongbin; Liu, Yinghong; Zhang, Junjie; Hu, Yufeng; Yu, Guowu; Li, Jian; Xu, Zhanbin; Huang, Yubi

    2016-01-01

    In southwest China, some maize landraces have long been isolated geographically, and have phenotypes that differ from those of widely grown cultivars. These landraces may harbor rich genetic variation responsible for those phenotypes. Four-row Wax is one such landrace, with four rows of kernels on the cob. We resequenced the genome of Four-row Wax, obtaining 50.46 Gb sequence at 21.87× coverage, then identified and characterized 3,252,194 SNPs, 213,181 short InDels (1–5 bp) and 39,631 structural variations (greater than 5 bp). Of those, 312,511 (9.6%) SNPs were novel compared to the most detailed haplotype map (HapMap) SNP database of maize. Characterization of variations in reported kernel row number (KRN) related genes and KRN QTL regions revealed potential causal mutations in fea2, td1, kn1, and te1. Genome-wide comparisons revealed abundant genetic variations in Four-row Wax, which may be associated with environmental adaptation. The sequence and SNP variations described here enrich genetic resources of maize, and provide guidance into study of seed numbers for crop yield improvement. PMID:27242868

  8. CT assessment of tumour response to treatment: comparison of linear, cross-sectional and volumetric measures of tumour size.

    PubMed

    Sohaib, S A; Turner, B; Hanson, J A; Farquharson, M; Oliver, R T; Reznek, R H

    2000-11-01

    Changes in cross-sectional area are currently used to assess tumour response to treatment. The aims of this study were to validate a helical CT technique for volume determination using a series of phantoms and to compare tumour responses indicated by one-, two- and three-dimensional measures of tumour size change in patients treated for germ cell cancer or lymphoma. All studies were performed on an IGE HiSpeed Advantage helical CT scanner with an Advantage Windows workstation. Phantom volumes were calculated using volume reconstruction software and compared with reference volumes determined by water displacement. 20 lymph node masses were studied on serial CT scans in 16 patients treated with chemotherapy for germ cell cancer or lymphoma. For each lesion the maximum diameter, maximum cross-sectional area and volume were determined before and after treatment. Tumour response was assessed using the standard World Health Organisation criteria (i.e. changes in cross-sectional area) and the newly proposed unidimensional response evaluation criteria in solid tumour (RECIST). The CT volume measurement error was 1.0-5.1% for regularly shaped phantoms larger than 35 cm3. In the assessment of treatment response there was 90% agreement between one-dimensional (1D) and two-dimensional (2D) measurements and 100% agreement between 2D and three-dimensional (3D) measurements. CT volume measurements are accurate and reproducible, particularly for larger structures. Assessment of tumour response using 1D, 2D and 3D measures had limited influence on the classification of treatment response. However, the impact of CT assessment of tumour response using 1D, 2D and 3D measurements on clinical decisions and patient outcome remains to be determined. PMID:11144795

  9. Comparison of quantitative myocardial perfusion imaging CT to fluorescent microsphere-based flow from high-resolution cryo-images

    NASA Astrophysics Data System (ADS)

    Eck, Brendan L.; Fahmi, Rachid; Levi, Jacob; Fares, Anas; Wu, Hao; Li, Yuemeng; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) has the potential to provide quantitative measures of myocardial blood flow (MBF) which can aid the diagnosis of coronary artery disease. We evaluated the quantitative accuracy of MPI-CT in a porcine model of balloon-induced LAD coronary artery ischemia guided by fractional flow reserve (FFR). We quantified MBF at baseline (FFR=1.0) and under moderate ischemia (FFR=0.7) using MPI-CT and compared to fluorescent microsphere-based MBF from high-resolution cryo-images. Dynamic, contrast-enhanced CT images were obtained using a spectral detector CT (Philips Healthcare). Projection-based mono-energetic images were reconstructed and processed to obtain MBF. Three MBF quantification approaches were evaluated: singular value decomposition (SVD) with fixed Tikhonov regularization (ThSVD), SVD with regularization determined by the L-Curve criterion (LSVD), and Johnson-Wilson parameter estimation (JW). The three approaches over-estimated MBF compared to cryo-images. JW produced the most accurate MBF, with average error 33.3+/-19.2mL/min/100g, whereas LSVD and ThSVD had greater over-estimation, 59.5+/-28.3mL/min/100g and 78.3+/-25.6 mL/min/100g, respectively. Relative blood flow as assessed by a flow ratio of LAD-to-remote myocardium was strongly correlated between JW and cryo-imaging, with R2=0.97, compared to R2=0.88 and 0.78 for LSVD and ThSVD, respectively. We assessed tissue impulse response functions (IRFs) from each approach for sources of error. While JW was constrained to physiologic solutions, both LSVD and ThSVD produced IRFs with non-physiologic properties due to noise. The L-curve provided noise-adaptive regularization but did not eliminate non-physiologic IRF properties or optimize for MBF accuracy. These findings suggest that model-based MPI-CT approaches may be more appropriate for quantitative MBF estimation and that cryo-imaging can support the development of MPI-CT by providing spatial distributions of MBF.

  10. Radiation absorbed from dental implant radiography: a comparison of linear tomography, CT scan, and panoramic and intra-oral techniques

    SciTech Connect

    Clark, D.E.; Danforth, R.A.; Barnes, R.W.; Burtch, M.L. )

    1990-01-01

    Absorbed radiation dose in bone marrow, thyroid, salivary gland, eye, and skin entrance was determined by placement of lithium fluoride thermoluminescent dosimeters (TLD's) at selected anatomical sites within and on a human-like x-ray phantom. The phantom was exposed to radiation from linear tomographic and computer-assisted tomographic (CT) simulated dental implant radiographic examinations. The mean dose was determined for each anatomical site. Resulting dose measurements from linear tomography and computer-assisted tomography are compared with reported panoramic and intra-oral doses. CT examination delivered the greatest dose, while linear tomography was generally lowest. Panoramic and intra-oral doses were similar to those of linear tomography.

  11. 68Ga-HBED-CC-PSMA PET/CT Versus Histopathology in Primary Localized Prostate Cancer: A Voxel-Wise Comparison

    PubMed Central

    Zamboglou, Constantinos; Schiller, Florian; Fechter, Tobias; Wieser, Gesche; Jilg, Cordula Annette; Chirindel, Alin; Salman, Nasr; Drendel, Vanessa; Werner, Martin; Mix, Michael; Meyer, Philipp Tobias; Grosu, Anca Ligia

    2016-01-01

    Purpose: We performed a voxel-wise comparison of 68Ga-HBED-CC-PSMA PET/CT with prostate histopathology to evaluate the performance of 68Ga-HBED-CC-PSMA for the detection and delineation of primary prostate cancer (PCa). Methodology: Nine patients with histopathological proven primary PCa underwent 68Ga-HBED-CC-PSMA PET/CT followed by radical prostatectomy. Resected prostates were scanned by ex-vivo CT in a special localizer and histopathologically prepared. Histopathological information was matched to ex-vivo CT. PCa volume (PCa-histo) and non-PCa tissue in the prostate (NPCa-histo) were processed to obtain a PCa-model, which was adjusted to PET-resolution (histo-PET). Each histo-PET was coregistered to in-vivo PSMA-PET/CT data. Results: Analysis of spatial overlap between histo-PET and PSMA PET revealed highly significant correlations (p < 10-5) in nine patients and moderate to high coefficients of determination (R²) from 42 to 82 % with an average of 60 ± 14 % in eight patients (in one patient R2 = 7 %). Mean SUVmean in PCa-histo and NPCa-histo was 5.6 ± 6.1 and 3.3 ± 2.5 (p = 0.012). Voxel-wise receiver-operating characteristic (ROC) analyses comparing the prediction by PSMA-PET with the non-smoothed tumor distribution from histopathology yielded an average area under the curve of 0.83 ± 0.12. Absolute and relative SUV (normalized to SUVmax) thresholds for achieving at least 90 % sensitivity were 3.19 ± 3.35 and 0.28 ± 0.09, respectively. Conclusions: Voxel-wise analyses revealed good correlations of 68Ga-HBED-CC-PSMA PET/CT and histopathology in eight out of nine patients. Thus, PSMA-PET allows a reliable detection and delineation of PCa as basis for PET-guided focal therapies. PMID:27446496

  12. Management controls on nitrous oxide emissions from row crop agriculture

    NASA Astrophysics Data System (ADS)

    Gelfand, I.; Shcherbak, I.; Millar, N.; Robertson, G. P.

    2011-12-01

    Agriculture is a significant source of the potent greenhouse gas (GHG) nitrous oxide (N2O), accounting for ~70% of total anthropic N2O emissions in the US primarily as a result of N fertilizer application. Emissions of N2O are the largest contributor to the global warming potential of row-crop agriculture. Management, including choice of crop type and rotation strongly impacts N2O emissions, but continuous emissions data from row-crops over multiple rotations are lacking. Empirical quantification of these long-term emissions and the development of crop- and rotation-specific N2O emission factors are vital for improving estimates of agricultural GHG emissions, important for informing management practices to reduce agriculture's GHG footprint, and developing mitigation protocols for environmental markets. Over 20 years we measured soil N2O emissions and calculated crop and management specific emission factors in four continuous rotations of corn (Zea mays) - soybean (Glycine max) - wheat (Triticum aestivum) under conventional tillage (CT), zero tillage (NT), low chemical input (LI), and biologically (Org) based management. Two of these systems (LI and Org) included winter cover crops, red clover (Trifolium pratense) or ray (Secale cereale). While average soil N2O fluxes in all systems where similar (2.9±0.2 to 3.8±0.5 g N2O-N ha-1 d-1), there was a significant interaction of total emissions with crop and phase. Surprisingly, the lowest total emissions from the corn period of the rotation were from CT, and the highest from LI, with 608±4 and 983±8 g N2O-N ha-1 crop year-1, respectively. Total emissions during the wheat period of the rotation showed the opposite trend, with total emissions of 942±7 and 524±38 g N2O-N ha-1 crop year-1, for CT ant LI, respectively. Total emissions from the soybean period of the rotation were highest under NT and lowest under CT management (526±5 and 296±2 g N2O-N ha-1 crop year-1, respectively). Emission efficiency, N2O emitted

  13. In vivo comparison of tantalum, tungsten, and bismuth enteric contrast agents to complement intravenous iodine for double-contrast dual-energy CT of the bowel.

    PubMed

    Rathnayake, Samira; Mongan, John; Torres, Andrew S; Colborn, Robert; Gao, Dong-Wei; Yeh, Benjamin M; Fu, Yanjun

    2016-07-01

    To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall from intraluminal contrast, we scanned 16 rabbits on a clinical DECT scanner: n = 3 using only iodinated intravenous contrast, and n = 13 double-contrast enhanced scans using iodinated intravenous contrast and experimental enteric non-iodinated contrast agents in the bowel lumen (five bismuth, four tungsten, and four tantalum based). Representative image pairs from conventional CT images and DECT iodine density maps of small bowel (116 pairs from 232 images) were viewed by four abdominal imaging attending radiologists to independently score each comparison pair on a visual analog scale (-100 to +100%) for (1) preference in small bowel wall visualization and (2) preference in completeness of intraluminal enteric contrast subtraction. Median small bowel wall visualization was scored 39 and 42 percentage points (95% CI 30-44% and 36-45%, both p < 0.001) higher for double-contrast DECT than for conventional CT with enteric tungsten and tantalum contrast, respectively. Median small bowel wall visualization for double-contrast DECT was scored 29 and 35 percentage points (95% CI 20-35% and 33-39%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Median completeness of intraluminal enteric contrast subtraction in double-contrast DECT iodine density maps was scored 28 and 29 percentage points (95% CI 15-31% and 28-33%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Results suggest that in vivo double-contrast DECT with iodinated intravenous and either tantalum- or tungsten-based enteric contrast provides better visualization of small bowel than conventional CT. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26892945

  14. A comparison of the thresholding strategies of micro-CT for periodontal bone loss: a pilot study

    PubMed Central

    Chang, P-C; Liang, K; Lim, JC; Chung, M-C; Chien, L-Y

    2013-01-01

    Objectives: Micro-CT provides three-dimensional details and has been widely used for biomedical assessments. This study aimed to determine the most appropriate threshold method for quantitatively assessing the dynamics of periodontal destruction. Methods: Inflammation was induced by submerging a silk ligature in the sulcus of the maxillary second molars of rats, and the animals were killed prior to ligature placement and after 7 and 21 days. The maxillae were examined for the bone resorptive activities by micro-CT, histology and tartrate-resistant acid phosphatase staining. The imaging threshold was determined by CT phantom, global and local algorithms. A bone fraction measurement from each threshold-determining technique was compared with histomorphometry. The reliability and reproducibility were examined by the intraclass correlation coefficient (ICC) and the coefficient of variation. Results: Significant reduction of inflammatory infiltration (p < 0.01) and active osteoclastic resorption (p < 0.05) from Day 7 to Day 21 were noted. High inter- and intraexaminer agreement were demonstrated in both histomorphometric and micro-CT assessments (ICC > 0.98). The algorithm-based technique demonstrated stronger correlation to histomorphometry than phantom-based thresholds, and the highest agreement was presented by the local algorithm (ICC > 0.96). This, however, was considerably computationally expensive. Conclusions: The local threshold-determining algorithm is suggested for examining inflammation-induced bone loss. Further investigation will be aimed at enhancing computational efficiency. PMID:22842634

  15. Comparison of Image Quality of Shoulder CT Arthrography Conducted Using 120 kVp and 140 kVp Protocols

    PubMed Central

    Ahn, Se Jin; Chai, Jee Won; Choi, Ja-Young; Yoo, Hye Jin; Kim, Sae Hoon; Kang, Heung Sik

    2014-01-01

    Objective To compare the image quality of shoulder CT arthrography performed using 120 kVp and 140 kVp protocols. Materials and Methods Fifty-four CT examinations were prospectively included. CT scans were performed on each patient at 120 kVp and 140 kVp; other scanning parameters were kept constant. Image qualities were qualitatively and quantitatively compared with respect to noise, contrast, and diagnostic acceptability. Diagnostic acceptabilities were graded using a one to five scale as follows: 1, suboptimal; 2, below average; 3, acceptable; 4, above average; and 5, superior. Radiation doses were also compared. Results Contrast was better at 120 kVp, but noise was greater. No significant differences were observed between the 120 kVp and 140 kVp protocols in terms of diagnostic acceptability, signal-to-noise ratio, or contrast-to-noise ratio. Lowering tube voltage from 140 kVp to 120 kVp reduced the radiation dose by 33%. Conclusion The use of 120 kVp during shoulder CT arthrography reduces radiation dose versus 140 kVp without significant loss of image quality. PMID:25469085

  16. Role of New Functional MRI Techniques in the Diagnosis, Staging, and Followup of Gynecological Cancer: Comparison with PET-CT.

    PubMed

    Alvarez Moreno, Elena; Jimenez de la Peña, Mar; Cano Alonso, Raquel

    2012-01-01

    Recent developments in diagnostic imaging techniques have magnified the role and potential of both MRI and PET-CT in female pelvic imaging. This article reviews the techniques and clinical applications of new functional MRI (fMRI) including diffusion-weighted MRI (DWI), dynamic contrast-enhanced (DCE)-MRI, comparing with PET-CT. These new emerging provide not only anatomic but also functional imaging, allowing detection of small volumes of active tumor at diagnosis and early disease relapse, which may not result in detectable morphological changes at conventional imaging. This information is useful in distinguishing between recurrent/residual tumor and post-treatment changes and assessing treatment response, with a clear impact on patient management. Both PET-CT and now fMRI have proved to be very valuable tools for evaluation of gynecologic tumors. Most papers try to compare these techniques, but in our experience both are complementary in management of these patients. Meanwhile PET-CT is superior in diagnosis of ganglionar disease; fMRI presents higher accuracy in local preoperative staging. Both techniques can be used as biomarkers of tumor response and present high accuracy in diagnosis of local recurrence and peritoneal dissemination, with complementary roles depending on histological type, anatomic location and tumoral volume. PMID:22315683

  17. Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

    SciTech Connect

    Zhang, Yakun; Li, Xiang; Segars, W. Paul; Samei, Ehsan

    2014-02-15

    Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDI{sub vol} and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose

  18. Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

    PubMed Central

    Zhang, Yakun; Li, Xiang; Segars, W. Paul; Samei, Ehsan

    2014-01-01

    Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDIvol and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose metrics

  19. Influence of ultranarrow row and conventional row cotton on the last effective boll population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The last effective boll population is the basis for many cotton (Gossypium hirsutum L.) management decisions such as defoliation timing. The objective of this research was to determine the last effective boll population for both ultra-narrow row cotton (UNRC), grown in rows spaced 25 cm or less, an...

  20. Yankee Rowe isotopics benchmark using MCNP-XT

    SciTech Connect

    Xu, Z.; Whitmer, C.

    2013-07-01

    The Yankee Rowe spent fuel isotopic data provides a valuable source to benchmark the burnup calculations as part of verification and validation (V and V) efforts for the TerraPower's Monte Carlo depletion code, MCNP-XT. A total of 71 fuel rods were selected in the Yankee Rowe isotopic measurements covering a burnup range up to 44 MWd/kg ({approx}4.4%) under both the asymptotic spectrum and the non-asymptotic spectrum. The MCNP-XT pin cell depletion provides a comparison against the asymptotic spectrum measurement; and full assembly depletion with 322 depletion materials provides comparisons against various non-asymptotic depletion conditions. All calculations are performed based on the recent ENDF/B-VII.O data. Furthermore, the Monte Carlo depletion uncertainties and biases were examined showing their effect as insignificant. The set of burnup calculations cover the scattered experimental measurements demonstrating excellent agreement with the measured values. This benchmark exercise demonstrates the depletion analysis capability of the MCNP-XT code and validates the low burnup range. (authors)

  1. Optical RAM row access using WDM-enabled all-passive row/column decoders

    NASA Astrophysics Data System (ADS)

    Papaioannou, Sotirios; Alexoudi, Theoni; Kanellos, George T.; Miliou, Amalia; Pleros, Nikos

    2014-03-01

    Towards achieving a functional RAM organization that reaps the advantages offered by optical technology, a complete set of optical peripheral modules, namely the Row (RD) and Column Decoder (CD) units, is required. In this perspective, we demonstrate an all-passive 2×4 optical RAM RD with row access operation and subsequent all-passive column decoding to control the access of WDM-formatted words in optical RAM rows. The 2×4 RD exploits a WDM-formatted 2-bit-long memory WordLine address along with its complementary value, all of them encoded on four different wavelengths and broadcasted to all RAM rows. The RD relies on an all-passive wavelength-selective filtering matrix (λ-matrix) that ensures a logical `0' output only at the selected RAM row. Subsequently, the RD output of each row drives the respective SOA-MZI-based Row Access Gate (AG) to grant/block the entry of the incoming data words to the whole memory row. In case of a selected row, the data word exits the row AG and enters the respective CD that relies on an allpassive wavelength-selective Arrayed Waveguide Grating (AWG) for decoding the word bits into their individual columns. Both RD and CD procedures are carried out without requiring any active devices, assuming that the memory address and data word bits as well as their inverted values will be available in their optical form by the CPU interface. Proof-of-concept experimental verification exploiting cascaded pairs of AWGs as the λ-matrix is demonstrated at 10Gb/s, providing error-free operation with a peak power penalty lower than 0.2dB for all optical word channels.

  2. Biomechanical evaluation of a single-row versus double-row repair for complete subscapularis tears.

    PubMed

    Wellmann, Mathias; Wiebringhaus, Philipp; Lodde, Ina; Waizy, Hazibullah; Becher, Christoph; Raschke, Michael J; Petersen, Wolf

    2009-12-01

    The purpose of the study was to compare a single-row repair and a double-row repair technique for the specific characteristics of a complete subscapularis lesion. Ten pairs of human cadaveric shoulder human shoulder specimens were tested for stiffness and ultimate tensile strength of the intact tendons in a load to failure protocol. After a complete subscapularis tear was provoked, the specimens were assigned to two treatment groups: single-row repair (1) and a double-row repair using a "suture bridge" technique (2). After repair cyclic loading a subsequent load to failure protocol was performed to determine the ultimate tensile load, the stiffness and the elongation behaviour of the reconstructions. The intact subscapularis tendons had a mean stiffness of 115 N/mm and a mean ultimate load of 720 N. The predominant failure mode of the intact tendons was a tear at the humeral insertion site (65%). The double-row technique restored 48% of the ultimate load of the intact tendons (332 N), while the single-row technique revealed a significantly lower ultimate load of 244 N (P = 0.001). In terms of the stiffness, the double-row technique showed a mean stiffness of 81 N/mm which is significantly higher compared to the stiffness of the single-row repairs of 55 N/mm (P = 0.001). The double-row technique has been shown to be stronger and stiffer when compared to a conventional single-row repair. Therefore, this technique is recommended from a biomechanical point of view irrespectively if performed by an open or arthroscopic approach. PMID:19693488

  3. Standardized Uptake Values from PET/MRI in Metastatic Breast Cancer: An Organ-based Comparison With PET/CT

    PubMed Central

    Pujara, Akshat C.; Raad, Roy A.; Ponzo, Fabio; Wassong, Carolyn; Babb, James S.; Moy, Linda; Melsaether, Amy N.

    2016-01-01

    Quantitative standardized uptake values (SUVs) from fluorine-18 (18F) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) are commonly used to evaluate the extent of disease and response to treatment in breast cancer patients. Recently, PET/magnetic resonance imaging (MRI) has been shown to qualitatively detect metastases from various primary cancers with similar sensitivity to PET/CT. However, quantitative validation of PET/ MRI requires assessing the reliability of SUVs from MR attenuation correction (MRAC) relative to CT attenuation correction (CTAC). The purpose of this retrospective study was to assess the utility of PET/MRI-derived SUVs in breast cancer patients by testing the hypothesis that SUVs derived from MRAC correlate well with those from CTAC. Between August 2012 and May 2013, 35 breast cancer patients (age 37–78 years, 1 man) underwent clinical 18F-FDG PET/CT followed by PET/MRI. One hundred seventy metastases were seen in 21 of 35 patients; metastases to bone in 16 patients, to liver in seven patients, and to nonaxillary lymph nodes in eight patients were sufficient for statistical analysis on an organ-specific per patient basis. SUVs in the most FDG-avid metastasis per organ per patient from PET/CT and PET/MRI were measured and compared using Pearson’s correlations. Correlations between CTAC- and MRAC-derived SUVmax and SUVmean in 31 metastases to bone, liver, and nonaxillary lymph nodes were strong overall (ρ= 0.80, 0.81). SUVmax and SUVmean correlations were also strong on an organ-specific basis in 16 bone metastases (ρ= 0.76, 0.74), seven liver metastases (ρ= 0.85, 0.83), and eight nonaxillary lymph node metastases (ρ= 0.95, 0.91). These strong organ-specific correlations between SUVs from PET/CT and PET/MRI in breast cancer metastases support the use of SUVs from PET/MRI for quantitation of 18F-FDG activity. PMID:26843433

  4. Comparison of analytical and numerical approaches for CT-based aberration correction in transcranial passive acoustic imaging

    NASA Astrophysics Data System (ADS)

    Jones, Ryan M.; Hynynen, Kullervo

    2016-01-01

    Computed tomography (CT)-based aberration corrections are employed in transcranial ultrasound both for therapy and imaging. In this study, analytical and numerical approaches for calculating aberration corrections based on CT data were compared, with a particular focus on their application to transcranial passive imaging. Two models were investigated: a three-dimensional full-wave numerical model (Connor and Hynynen 2004 IEEE Trans. Biomed. Eng. 51 1693-706) based on the Westervelt equation, and an analytical method (Clement and Hynynen 2002 Ultrasound Med. Biol. 28 617-24) similar to that currently employed by commercial brain therapy systems. Trans-skull time delay corrections calculated from each model were applied to data acquired by a sparse hemispherical (30 cm diameter) receiver array (128 piezoceramic discs: 2.5 mm diameter, 612 kHz center frequency) passively listening through ex vivo human skullcaps (n  =  4) to emissions from a narrow-band, fixed source emitter (1 mm diameter, 516 kHz center frequency). Measurements were taken at various locations within the cranial cavity by moving the source around the field using a three-axis positioning system. Images generated through passive beamforming using CT-based skull corrections were compared with those obtained through an invasive source-based approach, as well as images formed without skull corrections, using the main lobe volume, positional shift, peak sidelobe ratio, and image signal-to-noise ratio as metrics for image quality. For each CT-based model, corrections achieved by allowing for heterogeneous skull acoustical parameters in simulation outperformed the corresponding case where homogeneous parameters were assumed. Of the CT-based methods investigated, the full-wave model provided the best imaging results at the cost of computational complexity. These results highlight the importance of accurately modeling trans-skull propagation when calculating CT-based aberration corrections

  5. Neutron camera employing row and column summations

    DOEpatents

    Clonts, Lloyd G.; Diawara, Yacouba; Donahue, Jr, Cornelius; Montcalm, Christopher A.; Riedel, Richard A.; Visscher, Theodore

    2016-06-14

    For each photomultiplier tube in an Anger camera, an R.times.S array of preamplifiers is provided to detect electrons generated within the photomultiplier tube. The outputs of the preamplifiers are digitized to measure the magnitude of the signals from each preamplifier. For each photomultiplier tube, a corresponding summation circuitry including R row summation circuits and S column summation circuits numerically add the magnitudes of the signals from preamplifiers for each row and for each column to generate histograms. For a P.times.Q array of photomultiplier tubes, P.times.Q summation circuitries generate P.times.Q row histograms including R entries and P.times.Q column histograms including S entries. The total set of histograms include P.times.Q.times.(R+S) entries, which can be analyzed by a position calculation circuit to determine the locations of events (detection of a neutron).

  6. Comparison of fan-beam, cone-beam, and spiral scan reconstruction in x-ray micro-CT

    NASA Astrophysics Data System (ADS)

    Sasov, Alexander

    2001-06-01

    We developed and tested reconstruction software packages for different algorithms: fan-beam, cone-beam (Feldkamp) and spiral (helical) scans. All algorithms were applied to different simulations as well as to the real datasets from the commercial micro-CT instruments. From the results of testing a number of strong and weak points at different approaches was found. Several examples from the different application areas (bone microstructure, industrial applications) show typical reconstruction artifacts with different algorithms.

  7. Comparison of DXA and CT in the assessment of body composition in premenopausal women with obesity and anorexia nervosa.

    PubMed

    Bredella, Miriam A; Ghomi, Reza Hosseini; Thomas, Bijoy J; Torriani, Martin; Brick, Danielle J; Gerweck, Anu V; Misra, Madhusmita; Klibanski, Anne; Miller, Karen K

    2010-11-01

    Accurate methods for assessing body composition in subjects with obesity and anorexia nervosa (AN) are important for determination of metabolic and cardiovascular risk factors and to monitor therapeutic interventions. The purpose of our study was to assess the accuracy of dual-energy X-ray absorptiometry (DXA) for measuring abdominal and thigh fat, and thigh muscle mass in premenopausal women with obesity, AN, and normal weight compared to computed tomography (CT). In addition, we wanted to assess the impact of hydration on DXA-derived measures of body composition by using bioelectrical impedance analysis (BIA). We studied a total of 91 premenopausal women (34 obese, 39 with AN, and 18 lean controls). Our results demonstrate strong correlations between DXA- and CT-derived body composition measurements in AN, obese, and lean controls (r = 0.77-0.95, P < 0.0001). After controlling for total body water (TBW), the correlation coefficients were comparable. DXA trunk fat correlated with CT visceral fat (r = 0.51-0.70, P < 0.0001). DXA underestimated trunk and thigh fat and overestimated thigh muscle mass and this error increased with increasing weight. Our study showed that DXA is a useful method for assessing body composition in premenopausal women within the phenotypic spectrum ranging from obesity to AN. However, it is important to recognize that DXA may not accurately assess body composition in markedly obese women. The level of hydration does not significantly affect most DXA body composition measurements, with the exceptions of thigh fat. PMID:20111013

  8. CT estimations of mean attenuation values and volume in testicular tumors: a comparison with surgical and histologic findings

    SciTech Connect

    Husband, J.E.; Hawkes, D.J.; Peckham, M.J.

    1982-08-01

    Lymphadenectomy was carried out in 40 patients with retroperitoneal nodal metastases from testicular tumors who had undergone chemotherapy with or without radiation therapy. Two other patients, who died of their disease during chemotherapy, were included in the study. The postoperative or postmortem histologic results were compared with the mean tumor attenuation values and tumor volumes calculated from computed tomographic (CT) examinations.There was good separation between changes in CT numbers for those masses with persistent active malignancy (37.7 +/- 4.8 HU) and those masses with no evidence of malignancy (18.7 +/- 7.8 HU). Serum markers were elevated at the time of surgery in only two of the seven patients with active malignancy. There was no correlation between volume and malignancy or nonmalignancy for tumors greater than 20 ml; tumors less than 20 ml showed no evidence of malignancy. It is proposed that the mean CT number may be the most important parameter for measuring the therapeutic response of abdominal metastases from testicular tumors larger than 20 ml.

  9. CT -- Body

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses special x-ray ... Body? What is CT Scanning of the Body? Computed tomography, more commonly known as a CT or CAT ...

  10. Trauma therapy for death row families.

    PubMed

    Long, Walter C

    2011-01-01

    The family members of death row inmates undergo unique suffering that includes disenfranchised grief and intense psychological trauma. In Texas, where executions occur at a rate of 1 every 2 weeks, this class of trauma victims presumably is large, a fact that should generate public mental health concern. Yet the class remains virtually unknown to the therapeutic community. Very little has been done to address the trauma healing needs of death row families. This theoretical paper proposes that structural therapy designed to reengage attachment relationships and reempower family members' innate resources to emotionally regulate one another may provide one of the most effective means of helping this population survive trauma. PMID:21967176

  11. Comparison of effective dose and lifetime risk of cancer incidence of CT attenuation correction acquisitions and radiopharmaceutical administration for myocardial perfusion imaging

    PubMed Central

    Szczepura, K; Hogg, P

    2014-01-01

    Objective: To measure the organ dose and calculate effective dose from CT attenuation correction (CTAC) acquisitions from four commonly used gamma camera single photon emission CT/CT systems. Methods: CTAC dosimetry data was collected using thermoluminescent dosemeters on GE Healthcare's Infinia™ Hawkeye™ (GE Healthcare, Buckinghamshire, UK) four- and single-slice systems, Siemens Symbia™ T6 (Siemens Healthcare, Erlangen, Germany) and the Philips Precedence (Philips Healthcare, Amsterdam, Netherlands). Organ and effective dose from the administration of 99mTc-tetrofosmin and 99mTc-sestamibi were calculated using International Commission of Radiological Protection reports 80 and 106. Using these data, the lifetime biological risk was calculated. Results: The Siemens Symbia gave the lowest CTAC dose (1.8 mSv) followed by the GE Infinia Hawkeye single-slice (1.9 mSv), GE Infinia Hawkeye four-slice (2.5 mSv) and Philips Precedence v. 3.0. Doses were significantly lower than the calculated doses from radiopharmaceutical administration (11 and 14 mSv for 99mTc-tetrofosmin and 99mTc-sestamibi, respectively). Overall lifetime biological risks were lower, which suggests that using CTAC data posed minimal risk to the patient. Comparison of data for breast tissue demonstrated a higher risk than that from the radiopharmaceutical administration. Conclusion: CTAC doses were confirmed to be much lower than those from radiopharmaceutical administration. The localized nature of the CTAC exposure compared to the radiopharmaceutical biological distribution indicated dose and risk to the breast to be higher. Advances in knowledge: This research proved that CTAC is a comparatively low-dose acquisition. However, it has been shown that there is increased risk for breast tissue especially in the younger patients. As per legislation, justification is required and CTAC should only be used in situations that demonstrate sufficient net benefit. PMID:24998249

  12. Comparison Between Prospectively Electrocardiogram-Gated High-Pitch Mode and Retrospectively Electrocardiogram-Gated Mode for Dual-Source CT Coronary Angiography

    PubMed Central

    Koplay, Mustafa; Celik, Mahmut; Avcı, Ahmet; Erdogan, Hasan; Demir, Kenan; Sivri, Mesut; Nayman, Alaaddin

    2015-01-01

    Summary Background We aimed to report the image quality, relationship between heart rate and image quality, amount of contrast agent given to the patients and radiation doses in coronary CT angiography (CTA) obtained by using high-pitch prospectively ECG-gated “Flash Spiral” technique (method A) or retrospectively ECG-gated technique (method B) using 128×2-slice dual-source CT. Material/Methods A total of 110 patients who were evaluated with method A and method B technique with a 128×2-detector dual-source CT device were included in the study. Patients were divided into three groups based on their heart rates during the procedure, and a relationship between heart rate and image quality were evaluated. The relationship between heart rate, gender and radiation dose received by the patients was compared. Results A total of 1760 segments were evaluated in terms of image quality. Comparison of the relationship between heart rate and image quality revealed a significant difference between heart rate <60 beats/min group and >75 beats/min group whereas <60 beats/min and 60–75 beats/min groups did not differ significantly. The average effective dose for coronary CTA was calculated as 1.11 mSv (0.47–2.01 mSv) for method A and 8.22 mSv (2.19–12.88 mSv) for method B. Conclusions Method A provided high quality images with doses as low as <1 mSv in selected patients who have low heart rates with a high negative predictive value to rule out coronary artery disease. Although method B increases the amount of effective dose, it provides high diagnostic quality images for patients who have a high heart rate and arrhythmia which makes it is difficult to obtain images. PMID:26767072

  13. Normalized CT Dose Index of the CT Scanners Used in the National Lung Screening Trial

    PubMed Central

    Cody, Dianna D.; Kim, Hyun-Jung; Cagnon, Christopher H.; Larke, Frederick J.; McNitt-Gray, Michael M.; Kruger, Randell L.; Flynn, Michael J.; Seibert, J. Anthony; Judy, Philip F.; Wu, Xizeng

    2010-01-01

    The National Lung Screening Trial (NLST) includes 33 participating institutions, which performed 75, 133 lung cancer screening CT exams from 26,724 subjects during 2002–2007. For trial quality assurance reasons, CT radiation dose measurement data were collected from all multidetector-row CT scanners used in the NLST. A total of 247 measurements on 96 multi-row detector scanners were collected using a standard CT dose index (CTDI) measurement protocol. The scan parameters employed in the measurements (tube voltage, mAs and detector-channel configuration) were set according to trial-protocol for average size subjects. The normalized CTDIw (computed as CTDIw /mAs) obtained from each trial-participating scanner was tabulated. This study demonstrated a statistically significant difference in normalized CT dose index among CT scanner manufacturers, likely due to design differences such as filtration, bow-tie design and geometry. Our findings also indicated a statistically significant difference in normalized CT dose index among CT scanner models within GE, Siemens, and Philips. We also demonstrated a statistically significant difference in normalized CT dose index among all models and all manufacturers. And, we demonstrated a statistically significant difference in normalized CT dose index from CT scanners among manufacturers when grouped by 4 or 8 data channels vs 16, 32, or 64 channels, suggesting improved dose efficiency in more complex scanners. Average normalized CT dose index values varied by almost a factor of two across all scanners from all manufacturers. This study was focused on machine specific normalized CT dose index; patient dose and image quality were not addressed. PMID:20489094

  14. Comparison of Multidetector CT and Gadobutrol-Enhanced MR Imaging for Evaluation of Small, Solid Pancreatic Lesions

    PubMed Central

    Choi, Tae Won; Kim, Jung Hoon; Yu, Mi Hye; Han, Joon Koo; Choi, Byung Ihn

    2016-01-01

    Objective To compare multidetector computed tomography (MDCT) and MRI for lesion conspicuity, as well as the detection and characterization of small solid pancreatic lesions (SPLs). Materials and Methods 193 patients with small SPLs (< 3 cm) and 52 patients with normal pancreas who underwent both multiphasic MDCT and gadobutrol-enhanced MRI were included in our study. Two radiologists blinded to the pathologic diagnoses independently reviewed those images, and determined the detection of "SPL per se" and "SPL in consideration of secondary features", the lesion conspicuity, the probability of pancreatic ductal adenocarcinoma (PDAC), and the most likely specific diagnosis. Results The sensitivity of MRI for "detection of SPL per se" was significantly higher than that of CT in both reviewers: 92.7% (179/193) and 97.9% (189/193), respectively, for reviewer 1 (p = 0.031) and 90.7% (175/193) and 99.5% (192/193), respectively, for reviewer 2 (p < 0.001). In addition, MRI provided better lesion conspicuity than MDCT for both reviewers (p < 0.001). However, CT and MRI did not show significant difference in sensitivity for "detection of SPL in consideration of secondary features", specificity for SPL detection, and differentiation of PDAC vs. non-PDAC (p > 0.05). The accuracies of CT and MRI for making a specific diagnosis were as follows: 85.7% (210/245) vs. 86.9% (213/245), respectively, for reviewer 1 (p = 0.736), and 91.8% (225/245) vs. 93.5% (229/245), respectively, for reviewer 2 (p = 0.454). Conclusion MRI showed better lesion conspicuity than MDCT, but did not show significantly different diagnostic performance compared with MDCT for detecting and characterizing small SPLs. PMID:27390542

  15. Simultaneous measurements of cerebral blood flow by the xenon/CT method and the microsphere method. A comparison

    SciTech Connect

    Gur, D.; Yonas, H.; Jackson, D.L.; Wolfson, S.K. Jr.; Rockette, H.; Good, W.F.; Cook, E.E.; Arena, V.C.; Willy, J.A.; Maitz, G.S.

    1985-10-01

    Simultaneous measurements of cerebral blood flow have been performed in baboons to assess the correlation between the acute and invasive nondiffusible microsphere technique and the noninvasive xenon-enhanced CT method. Blood flows in small tissue volumes (approximately 1 cm3) were directly compared. The results of these studies demonstrate a statistically significant association between the two methods (P less than .001). Similar correlations were obtained by both the Kendall tau (tau) and the Spearman (r) methods. The problems and limitations of such correlations are discussed.

  16. Radiometric surface temperature components for row crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature is a boundary condition often used in assessing soil moisture status and energy exchange from the soil-vegetation-atmosphere interface. For row crops having incomplete canopy cover, the radiometric surface temperature is a composite of sunlit and shaded vegetation and substr...

  17. An Improved Row/Column Scanning System.

    ERIC Educational Resources Information Center

    Weiss, Lawrence H.

    The use of row/column scanning, a technique for accessing a large number of selections with a single volitional action, is considered for individuals with disabilities. It is explained that such a scanning approach is particularly useful for those with only one volitional action, or those, such as people with cerebral palsy, who have pointing…

  18. 7. VIEW OF THREE BOATHOUSES FROM 'PENN AC ROWING ASSN' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF THREE BOATHOUSES FROM 'PENN AC ROWING ASSN' TO NORTH END OF 'VESPER,' LOOKING EAST FROM WEST BANK OF SCHUYLKILL RIVER - Boathouse Row, East River Drive, Philadelphia, Philadelphia County, PA

  19. Sci—Fri AM: Mountain — 02: A comparison of dose reduction methods on image quality for cone beam CT

    SciTech Connect

    Webb, R; Buckley, LA

    2014-08-15

    Modern radiotherapy uses highly conformai dose distributions and therefore relies on daily image guidance for accurate patient positioning. Kilovoltage cone beam CT is one technique that is routinely used for patient set-up and results in a high dose to the patient relative to planar imaging techniques. This study uses an Elekta Synergy linac equipped with XVI cone beam CT to investigate the impact of various imaging parameters on dose and image quality. Dose and image quality are assessed as functions of x-ray tube voltage, tube current and the number of projections in the scan. In each case, the dose measurements confirm that as each parameter increases the dose increases. The assessment of high contrast resolution shows little dependence on changes to the image technique. However, low contrast visibility suggests a trade off between dose and image quality. Particularly for changes in tube potential, the dose increases much faster as a function of voltage than the corresponding increase in low contrast image quality. This suggests using moderate values of the peak tube voltage (100 – 120 kVp) since higher values result in significant dose increases with little gain in image quality. Measurements also indicate that increasing tube current achieves the greatest degree of improvement in the low contrast visibility. The results of this study highlight the need to establish careful imaging protocols to limit dose to the patient and to limit changes to the imaging parameters to those cases where there is a clear clinical requirement for improved image quality.

  20. Development and evaluation of a combined cultivator and band sprayer with a row-centering RTK-GPS guidance system.

    PubMed

    Perez-Ruiz, Manuel; Carballido, Jacob; Agüera, Juan; Rodríguez-Lizana, Antonio

    2013-01-01

    Typically, low-pressure sprayers are used to uniformly apply pre- and post-emergent herbicides to control weeds in crop rows. An innovative machine for weed control in inter-row and intra-row areas, with a unique combination of inter-row cultivation tooling and intra-row band spraying for six rows and an electro-hydraulic side-shift frame controlled by a GPS system, was developed and evaluated. Two weed management strategies were tested in the field trials: broadcast spraying (the conventional method) and band spraying with mechanical weed control using RTK-GPS (the experimental method). This approach enabled the comparison between treatments from the perspective of cost savings and efficacy in weed control for a sugar beet crop. During the 2010-2011 season, the herbicide application rate (112 L ha(-1)) of the experimental method was approximately 50% of the conventional method, and thus a significant reduction in the operating costs of weed management was achieved. A comparison of the 0.2-trimmed means of weed population post-treatment showed that the treatments achieved similar weed control rates at each weed survey date. Sugar beet yields were similar with both methods (p = 0.92). The use of the experimental equipment is cost-effective on ≥20 ha of crops. These initial results show good potential for reducing herbicide application in the Spanish beet industry. PMID:23478600

  1. SU-E-I-17: Comparison of Two Novel Algorithms for the Modulation Transfer Function of CT Using a Simple Cylindrical Phantom

    SciTech Connect

    Kam, S; Youn, H; Kim, H; Jeon, H; Park, D

    2014-06-01

    Purpose: To compare and analyze two novel algorithms for the assessment of modulation transfer functions (MTFs) of computed tomography (CT) systems using a simple acrylic cylindrical phantom Method and Materials: Images of the acrylic cylindrical phantom were acquired by a GE LightSpeed 16 RT (GE Healthcare, Milwaukee, WI) using 120 kVp, 330 mA, 2.5 mm slice thickness, 10 cm field-of view (FOV), four reconstruction kernels (e.g. standard, soft, detail, bone, and lung). Two different algorithms were used to analyze images for MTF assessment. First, Richard et al. suggested a task-based MTF assessment method through an edge spread function (ESF) which described pixel intensities as a function of distance from the center. The MTF was obtained as the absolute value of Fourier transform of the differentiated ESF. Second, Ohkubo et al. devised an effective method to determine the point spread function (PSF) of CT system accompanied with verification. The line spread function (LSF), which was the one-dimensional integration of the PSF, was used to obtain the MTF. We validated the reliability of two above-mentioned methods through the comparison with a conventional method using a thin tungsten wire phantom. Results: The measured MTFs by two methods were mostly similar each other for standard, soft, and detail kernels. In 0.6 lp/mm, the MTF difference between two methods were 0.012(standard), 0.004(soft), and 0.037(detail). They also coincided with the MTF by the conventional method well. However, there were considerable distinctions for bone and lung kernels containing edge enhancement that might cause undershoots near the peak of the LSF. Conclusions: We compared two novel methods to assess task-based MTFs for clinical CT systems especially using a simple acrylic cylindrical phantom with high-convenience and low-cost, and validated them against a conventional method. This work can provide a practical solution to users for the quality assurance of CT.

  2. Radiation model for row crops: II. Model evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relatively few radiation transfer studies have considered the impact of varying vegetation cover that typifies row crops, and meth¬ods to account for partial row crop cover have not been well investigated. Our objective was to evaluate a widely used radiation model that was modified for row crops ha...

  3. Biomass production of sugarcane on narrow-rows in Florida

    SciTech Connect

    Cayton, J.E.; Eiland, B.R.

    1981-01-01

    Sugarcane production for biomass was examined on three narrow-row patterns in Florida. Equipment and production methods were modified for planting, spraying and harvesting the narrow-row patterns. No large increases in yields of vigorous varieties were found when compared to those from conventional rows. Some increases were observed in varieties which have low stalk populations. 4 refs.

  4. Friendship and Disaffiliation Among the Skid Row Population

    ERIC Educational Resources Information Center

    Rooney, James F.

    1976-01-01

    Personal relationships of skid row men have been described in terms of disaffiliation and replacement of friends. Analysis of social relationships of Philadelphia skid row residents upheld the theory of replacement. The loss of relationships, however, was more closely associated with length of residence in skid row than with age. (Author)

  5. Penumbra Pattern Assessment in Acute Stroke Patients: Comparison of Quantitative and Non-Quantitative Methods in Whole Brain CT Perfusion

    PubMed Central

    Baumann, Alena B.; Meinel, Felix G.; Helck, Andreas D.; Opherk, Christian; Straube, Andreas; Reiser, Maximilian F.; Sommer, Wieland H.

    2014-01-01

    Background And Purpose While penumbra assessment has become an important part of the clinical decision making for acute stroke patients, there is a lack of studies measuring the reliability and reproducibility of defined assessment techniques in the clinical setting. Our aim was to determine reliability and reproducibility of different types of three-dimensional penumbra assessment methods in stroke patients who underwent whole brain CT perfusion imaging (WB-CTP). Materials And Methods We included 29 patients with a confirmed MCA infarction who underwent initial WB-CTP with a scan coverage of 100 mm in the z-axis. Two blinded and experienced readers assessed the flow-volume-mismatch twice and in two quantitative ways: Performing a volumetric mismatch analysis using OsiriX imaging software (MMVOL) and visual estimation of mismatch (MMEST). Complementarily, the semiquantitative Alberta Stroke Programme Early CT Score for CT perfusion was used to define mismatch (MMASPECTS). A favorable penumbral pattern was defined by a mismatch of ≥30% in combination with a cerebral blood flow deficit of ≤90 ml and an MMASPECTS score of ≥1, respectively. Inter- and intrareader agreement was determined by Kappa-values and ICCs. Results Overall, MMVOL showed considerably higher inter-/intrareader agreement (ICCs: 0.751/0.843) compared to MMEST (0.292/0.749). In the subgroup of large (≥50 mL) perfusion deficits, inter- and intrareader agreement of MMVOL was excellent (ICCs: 0.961/0.942), while MMEST interreader agreement was poor (0.415) and intrareader agreement was good (0.919). With respect to penumbra classification, MMVOL showed the highest agreement (interreader agreement: 25 agreements/4 non-agreements/κ: 0.595; intrareader agreement 27/2/0.833), followed by MMEST (22/7/0.471; 23/6/0.577), and MMASPECTS (18/11/0.133; 21/8/0.340). Conclusion The evaluated approach of volumetric mismatch assessment is superior to pure visual and ASPECTS penumbra pattern assessment in WB

  6. Comparison between traditional laboratory tests, permeability measurements and CT-based fluid flow modelling for cultural heritage applications.

    PubMed

    De Boever, Wesley; Bultreys, Tom; Derluyn, Hannelore; Van Hoorebeke, Luc; Cnudde, Veerle

    2016-06-01

    In this paper, we examine the possibility to use on-site permeability measurements for cultural heritage applications as an alternative for traditional laboratory tests such as determination of the capillary absorption coefficient. These on-site measurements, performed with a portable air permeameter, were correlated with the pore network properties of eight sandstones and one granular limestone that are discussed in this paper. The network properties of the 9 materials tested in this study were obtained from micro-computed tomography (μCT) and compared to measurements and calculations of permeability and the capillary absorption rate of the stones under investigation, in order to find the correlation between pore network characteristics and fluid management characteristics of these sandstones. Results show a good correlation between capillary absorption, permeability and network properties, opening the possibility of using on-site permeability measurements as a standard method in cultural heritage applications. PMID:26950624

  7. Comparison of Iohexol-380 and Iohexol-350 for Coronary CT Angiography: A Multicenter, Randomized, Double-Blind Phase 3 Trial

    PubMed Central

    Park, Eun-Ah; Kang, Doo Kyoung; Kim, Sung Jin; Kim, Young-Ju; Kim, Yookyung; Sung, Yon Mi; Song, Soon-Young; Oh, Yu-Whan; Yong, Hwan Seok; Lee, Heon; Jeon, Eui-Yong; Jin, Gong-Yong; Choi, Byoung Wook; Choi, Sang-Il

    2016-01-01

    Objective This multi-center, randomized, double-blind, phase 3 trial was conducted to compare the safety and efficacy of contrast agents iohexol-380 and iohexol-350 for coronary CT angiography in healthy subjects. Materials and Methods Volunteers were randomized to receive 420 mgI/kg of either iohexol-350 or iohexol-380 using a flow rate of 4 mL/sec. All adverse events were recorded. Two blinded readers independently reviewed the CT images and conflicting results were resolved by a third reader. Luminal attenuations (ascending aorta, left main coronary artery, and left ventricle) in Hounsfield units (HUs) and image quality on a 4-point scale were calculated. Results A total of 225 subjects were given contrast media (115 with iohexol-380 and 110 with iohexol-350). There was no difference in number of adverse drug reactions between groups: 75 events in 56 (48.7%) of 115 subjects in the iohexol-380 group vs. 74 events in 51 (46.4%) of 110 subjects in the iohexol-350 group (p = 0.690). No severe adverse drug reactions were recorded. Neither group showed an increase in serum creatinine. Significant differences in mean density between the groups was found in the ascending aorta: 375.8 ± 71.4 HU with iohexol-380 vs. 356.3 ± 61.5 HU with iohexol-350 (p = 0.030). No significant differences in image quality scores between both groups were observed for all three anatomic evaluations (all, p > 0.05). Conclusion Iohexol-380 provides improved enhancement of the ascending aorta and similar attenuation of the coronary arteries without any increase in adverse drug reactions, as compared with iohexol-350 using an identical amount of total iodine. PMID:27134522

  8. Comparison of physical quality assurance between Scanora 3D and 3D Accuitomo 80 dental CT scanners

    PubMed Central

    Ali, Ahmed S.; Fteita, Dareen; Kulmala, Jarmo

    2015-01-01

    Background The use of cone beam computed tomography (CBCT) in dentistry has proven to be useful in the diagnosis and treatment planning of several oral and maxillofacial diseases. The quality of the resulting image is dictated by many factors related to the patient, unit, and operator. Materials and methods In this work, two dental CBCT units, namely Scanora 3D and 3D Accuitomo 80, were assessed and compared in terms of quantitative effective dose delivered to specific locations in a dosimetry phantom. Resolution and contrast were evaluated in only 3D Accuitomo 80 using special quality assurance phantoms. Results Scanora 3D, with less radiation time, showed less dosing values compared to 3D Accuitomo 80 (mean 0.33 mSv, SD±0.16 vs. 0.18 mSv, SD±0.1). Using paired t-test, no significant difference was found in Accuitomo two scan sessions (p>0.05), while it was highly significant in Scanora (p>0.05). The modulation transfer function value (at 2 lp/mm), in both measurements, was found to be 4.4%. The contrast assessment of 3D Accuitomo 80 in the two measurements showed few differences, for example, the grayscale values were the same (SD=0) while the noise level was slightly different (SD=0 and 0.67, respectively). Conclusions The radiation dose values in these two CBCT units are significantly less than those encountered in systemic CT scans. However, the dose seems to be affected more by changing the field of view rather than the voltage or amperage. The low doses were at the expense of the image quality produced, which was still acceptable. Although the spatial resolution and contrast were inferior to the medical images produced in systemic CT units, the present results recommend adopting CBCTs in maxillofacial imaging because of low radiation dose and adequate image quality. PMID:26091832

  9. Characterization of scatter in cone-beam CT breast imaging: Comparison of experimental measurements and Monte Carlo simulation

    PubMed Central

    Chen, Yu; Liu, Bob; O’Connor, J. Michael; Didier, Clay S.; Glick, Stephen J.

    2009-01-01

    It is commonly understood that scattered radiation in x-ray computed tomography (CT) degrades the reconstructed image. As a precursor to developing scatter compensation methods, it is important to characterize this scatter using both empirical measurements and Monte Carlo simulations. Previous studies characterizing scatter using both experimental measurements and Monte Carlo simulations have been reported in diagnostic radiology and conventional mammography. The emerging technology of cone-beam CT breast imaging (CTBI) differs significantly from conventional mammography in the breast shape and imaging geometry, aspects that are important factors impacting the measured scatter. This study used a bench-top cone-beam CTBI system with an indirect flat-panel detector. A cylindrical phantom with equivalent composition of 50% fibroglandular and 50% adipose tissues was used, and scatter distributions were measured by beam stop and aperture methods. The GEANT4-based simulation package GATE was used to model x-ray photon interactions in the phantom and detector. Scatter to primary ratio (SPR) measurements using both the beam stop and aperture methods were consistent within 5% after subtraction of nonbreast scatter contributions and agree with the low energy electromagnetic model simulation in GATE. The validated simulation model was used to characterize the SPR in different CTBI conditions. In addition, a realistic, digital breast phantom was simulated to determine the characteristics of various scatter components that cannot be separated in measurements. The simulation showed that the scatter distribution from multiple Compton and Rayleigh scatterings, as well as from the single Compton scattering, has predominantly low-frequency characteristics. The single Rayleigh scatter was observed to be the primary contribution to the spatially variant scatter component. PMID:19378746

  10. SU-E-I-98: Dose Comparison for Pulmonary Embolism CT Studies: Single Energy Vs. Dual Energy

    SciTech Connect

    Mahmood, U; Erdi, Y

    2014-06-01

    Purpose: The purpose of this study was to assess and compare the size specific dose estimate (SSDE), dose length product (DLP) and noise relationship for pulmonary embolism studies evaluated by single source dual energy computed tomography (DECT) against conventional CT (CCT) studies in a busy cancer center and to determine the dose savings provided by DECT. Methods: An IRB-approved retrospective study was performed to determine the CTDIvol and DLP from a subset of patients scanned with both DECT and CCT over the past five years. We were able to identify 30 breast cancer patients (6 male, 24 female, age range 24 to 81) who had both DECT and CCT studies performed. DECT scans were performed with a GE HD 750 scanner (140/80 kVp, 480 mAs and 40 mm) and CCT scans were performed with a GE Lightspeed 16 slice scanner (120 kVp, 352 mAs, 20 mm). Image noise was measured by placing an ROI and recording the standard deviation of the mean HU along the descending aorta. Results: The average DECT patient size specific dose estimate was to be 14.2 ± 1.7 mGy as compared to 22.4 ± 2.7 mGy from CCT PE studies, which is a 37% reduction in the SSDE. The average DECT DLP was 721.8 ± 84.6 mGy-cm as compared to 981.8 ± 106.1 mGy-cm for CCT, which is a 26% decrease. Compared to CCT the image noise was found to decrease by 19% when using DECT for PE studies. Conclusion: DECT SSDE and DLP measurements indicate dose savings and image noise reduction when compared to CCT. In an environment that heavily debates CT patient doses, this study confirms the effectiveness of DECT in PE imaging.

  11. Comparison of Two Deformable Registration Algorithms in the Presence of Radiologic Change Between Serial Lung CT Scans.

    PubMed

    Cunliffe, Alexandra R; White, Bradley; Justusson, Julia; Straus, Christopher; Malik, Renuka; Al-Hallaq, Hania A; Armato, Samuel G

    2015-12-01

    We evaluated the image registration accuracy achieved using two deformable registration algorithms when radiation-induced normal tissue changes were present between serial computed tomography (CT) scans. Two thoracic CT scans were collected for each of 24 patients who underwent radiation therapy (RT) treatment for lung cancer, eight of whom experienced radiologically evident normal tissue damage between pre- and post-RT scan acquisition. For each patient, 100 landmark point pairs were manually placed in anatomically corresponding locations between each pre- and post-RT scan. Each post-RT scan was then registered to the pre-RT scan using (1) the Plastimatch demons algorithm and (2) the Fraunhofer MEVIS algorithm. The registration accuracy for each scan pair was evaluated by comparing the distance between landmark points that were manually placed in the post-RT scans and points that were automatically mapped from pre- to post-RT scans using the displacement vector fields output by the two registration algorithms. For both algorithms, the registration accuracy was significantly decreased when normal tissue damage was present in the post-RT scan. Using the Plastimatch algorithm, registration accuracy was 2.4 mm, on average, in the absence of radiation-induced damage and 4.6 mm, on average, in the presence of damage. When the Fraunhofer MEVIS algorithm was instead used, registration errors decreased to 1.3 mm, on average, in the absence of damage and 2.5 mm, on average, when damage was present. This work demonstrated that the presence of lung tissue changes introduced following RT treatment for lung cancer can significantly decrease the registration accuracy achieved using deformable registration. PMID:25822396

  12. CT Scans

    MedlinePlus

    ... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

  13. Quantitative Assessment of Left Ventricular Function and Myocardial Mass: A Comparison of Coronary CT Angiography with Cardiac MRI and Echocardiography

    PubMed Central

    Kara, Bedia; Nayman, Alaaddin; Guler, Ibrahim; Gul, Enes Elvin; Koplay, Mustafa; Paksoy, Yahya

    2016-01-01

    Summary Background The purpose of this study was to compare the left ventricular parameters obtained from multi-detector row computed tomography (MDCT) studies with two-dimensional echocardiography (2DE), and magnetic resonance imaging (MRI), which is accepted as the gold standard in the evaluation of left ventricular functions. The study also aimed to evaluate whether or not there is a relationship between the MR-Argus and CMR tools software programs which are used in post-process calculations of data obtained by MRI. Material/Methods Forty patients with an average age of 51.4±14.9 years who had been scanned with cardiac MDCT were evaluated with cardiac MRI and 2DE. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), cardiac output (CO), and myocardial mass values calculated by MDCT, MRI, and 2DE were compared with each other. Two different MR software programs were used to compare left ventricular functions. The CMR tools LV tutorials method is accepted as the gold standard because it can be used in three-dimensional functional evaluation. The Pearson Correlation and Bland-Altman analysis were performed to compare the results from the two MR methods (MR-Argus and CMR tools) and the results from both the MDCT and the 2DE with the CMR tools results. Results Strong positive correlations for EF values were found between the MDCT and CMR tools (r=0.702 p<0.001), and between the MR-Argus and CMR tools (r=0.746 p<0.001). The correlation between the 2DE and CMR tools (r=0.449 p<0.004), however, was only moderate. Similar results were obtained for the other parameters. The strongest correlation for ESV, EDV, and EF was between the two MR software programs. The correlation coefficient between the MDCT and CMR tools is close to the correlation coefficient between the two software programs. While the correlation between 2DE and CMR tools was satisfactory for ESV, EDV, and CO values, it was at a moderate level for the other

  14. Accuracy and Feasibility of Optoelectronic Sensors for Weed Mapping in Wide Row Crops

    PubMed Central

    Andújar, Dionisio; Ribeiro, Ángela; Fernández-Quintanilla, César; Dorado, José

    2011-01-01

    The main objectives of this study were to assess the accuracy of a ground-based weed mapping system that included optoelectronic sensors for weed detection, and to determine the sampling resolution required for accurate weed maps in maize crops. The optoelectronic sensors were located in the inter-row area of maize to distinguish weeds against soil background. The system was evaluated in three maize fields in the early spring. System verification was performed with highly reliable data from digital images obtained in a regular 12 m × 12 m grid throughout the three fields. The comparison in all these sample points showed a good relationship (83% agreement on average) between the data of weed presence/absence obtained from the optoelectronic mapping system and the values derived from image processing software (“ground truth”). Regarding the optimization of sampling resolution, the comparison between the detailed maps (all crop rows with sensors separated 0.75 m) with maps obtained with various simulated distances between sensors (from 1.5 m to 6.0 m) indicated that a 4.5 m distance (equivalent to one in six crop rows) would be acceptable to construct accurate weed maps. This spatial resolution makes the system cheap and robust enough to generate maps of inter-row weeds. PMID:22163740

  15. Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans

    SciTech Connect

    Straten, Marcel van; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; Lugt, Aad van der; Krestin, Gabriel P.; Niessen, Wiro J.

    2011-11-15

    Purpose: To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Methods: Four different bone removal methods were applied to CT scans of an anthropomorphic thorax phantom, acquired with a second generation dual source CT scanner. The methods differed by the way information on the presence of bone was obtained (either by using an additional, nonenhanced scan or by scanning with two tube voltages at the same time) and by the way the bone was removed from the CTA images (either by masking or subtracting the bone). The phantom contained parts which mimic vessels of various diameters in direct contact with bone. Both a quantitative and qualitative analysis of image quality after bone removal was performed. Image quality was quantified by the contrast-to-noise ratio (CNR) normalized to the square root of the dose (CNRD). At locations where vessels touch bone, the quality of the bone removal and the vessel preservation were visually assessed. The dual energy based methods were assessed with and without the addition of a 0.4 mm tin filter to the high voltage x-ray tube filtration. For each bone removal method, the dose required to obtain a certain CNR after bone removal was compared with the dose of a reference scan with the same CNR but without automated bone removal. The CNRD value of the reference scan was maximized by choosing the lowest tube voltage available. Results: All methods removed the bone completely. CNRD values were higher for the masking based methods than for the subtraction based methods. Single energy based methods had a higher CNRD value than the corresponding dual energy based methods. For the subtraction based dual energy method, tin filtration improved the CNRD value with approximately 50%. For the masking based dual energy method, it was easier to differentiate between iodine and bone when tin filtration

  16. Assessment of Vascularity in Hepatic Alveolar Echinococcosis: Comparison of Quantified Dual-Energy CT with Histopathologic Parameters

    PubMed Central

    Jiang, Yi; Li, Jiaqi; Wang, Jing; Xiao, Hu; Li, Tingting; Liu, Hui; Liu, Wenya

    2016-01-01

    Purpose To investigate whether dual-energy computer tomography(DECT) could determine the angiographic vascularity of alveolar echinococcosis lesions by comparing the quantitative iodine concentration (IC) with the microvascular density (MVD). Material and Methods Twenty-five patients (16 men, 9 women; mean age, 40.9 ± 13.8 years) with confirmed hepatic alveolar echinococcosis (HAE) underwent DECT of the abdomen, consisting of arterial phase (AP), portal venous phase (PVP), and delayed phase (DP) scanning, in dual-source mode (100 kV/140 kV). Image data were processed with a DECT software algorithm that was designed for the evaluation of iodine distribution in the different layers (marginal zone, solid and cystic) of the lesions. The CT patterns of HAE lesions were classified into three types: solid type, pseudocystic type and ‘geographic map’ (mixed) type. The IC measurements in different layers and different types of lesions were statistically compared. MVD was examined using CD34 immunohistochemical staining of the resected HAE tissue and scored based on the percentage of positively stained cells and their intensity. Pearson’s correlation analysis was used to evaluate the potential correlation between DECT parameters and MVD. Results A total of 27 HAE lesions were evaluated, of which 9 were solid type, 3 were pseudocystic type and 15 were mixed type. The mean lesion size was 100.7 ± 47.3 mm. There was a significant difference in the IC measurements between different layers of HAE lesions during each scan phase (p < 0.001). The IC in the marginal zone was significantly higher than in the solid and cystic components in AP (2.15 mg/mL vs. 0.17 or 0.01 mg/mL), PVP (3.08 mg/mL vs. 0.1 or 0.02 mg/mL), and DP (2.93 mg/mL vs. 0.04 or 0.02 mg/mL). No significant difference was found among the different CT patterns of HAE lesions. Positive expression of CD34 in the marginal zones surrounding HAE lesions was found in 92.5% (25/27) of lesions, of which 18.5% (5

  17. Diffuse Large B-Cell Lymphoma: Prospective Multicenter Comparison of Early Interim FLT PET/CT versus FDG PET/CT with IHP, EORTC, Deauville, and PERCIST Criteria for Early Therapeutic Monitoring.

    PubMed

    Minamimoto, Ryogo; Fayad, Luis; Advani, Ranjana; Vose, Julie; Macapinlac, Homer; Meza, Jane; Hankins, Jordan; Mottaghy, Felix; Juweid, Malik; Quon, Andrew

    2016-07-01

    Purpose To compare the performance characteristics of interim fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) (after two cycles of chemotherapy) by using the most prominent standardized interpretive criteria (including International Harmonization Project [IHP] criteria, European Organization for Research and Treatment of Cancer [EORTC] criteria, and PET Response Criteria in Solid Tumors (PERCIST) versus those of interim (18)F fluorothymidine (FLT) PET/CT and simple visual interpretation. Materials and Methods This HIPAA-compliant prospective study was approved by the institutional review boards, and written informed consent was obtained. Patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL) underwent both FLT and FDG PET/CT 18-24 days after two cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone or rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin. For FDG PET/CT interpretation, IHP criteria, EORTC criteria, PERCIST, Deauville criteria, standardized uptake value, total lesion glycolysis, and metabolic tumor volume were used. FLT PET/CT images were interpreted with visual assessment by two reviewers in consensus. The interim (after cycle 2) FDG and FLT PET/CT studies were then compared with the end-of-treatment FDG PET/CT studies to determine which interim examination and/or criteria best predicted the result after six cycles of chemotherapy. Results From November 2011 to May 2014, there were 60 potential patients for inclusion, of whom 46 patients (24 men [mean age, 60.9 years ± 13.7; range, 28-78 years] and 22 women [mean age, 57.2 years ± 13.4; range, 25-76 years]) fulfilled the criteria. Thirty-four patients had complete response, and 12 had residual disease at the end of treatment. FLT PET/CT had a significantly higher positive predictive value (PPV) (91%) in predicting residual disease than did any FDG PET/CT interpretation method

  18. A comparison of lesion detection accuracy using digital mammography and flat-panel CT breast imaging (Honorable Mention Poster Award)

    NASA Astrophysics Data System (ADS)

    Gong, Xing; Vedula, Aruna A.; Thacker, Samta; Glick, Stephen J.

    2005-04-01

    Although conventional mammography is currently the best modality to detect early breast cancer, it is limited in that the recorded image represents the superposition of a 3D object onto a 2D plane. As an alternative, cone-beam CT breast imaging with a CsI based flat-panel imager (CTBI) has been proposed with the ability to provide 3D visualization of breast tissue. To investigate possible improvements in lesion detection accuracy using CTBI over digital mammography (DM), a computer simulation study was conducted using simulated lesions embedded into a structured 3D breast model. The computer simulation realistically modeled x-ray transport through a breast model, as well as the signal and noise propagation through the flat-panel imager. Polyenergetic x-ray spectra of W/Al 50 kVp for CTBI and Mo/Mo 28 kVp for DM were modeled. For the CTBI simulation, the intensity of the x-ray spectra for each projection view was determined so as to provide a total mean glandular dose (MGD) of 4 mGy, which is approximately equivalent to that given in a conventional two-view screening mammography study. Since only one DM view was investigated here, the intensity of the DM x-ray spectra was defined to give 2 mGy MGD. Irregular lesions were simulated by using a stochastic growth algorithm providing lesions with an effective diameter of 5 mm. Breast tissue was simulated by generating an ensemble of backgrounds with a power law spectrum. To evaluate lesion detection accuracy, a receiver operating characteristic (ROC) study was performed with 4 observers reading an ensemble of images for each case. The average area under the ROC curves (Az) was 0.94 for CTBI, and 0.81 for DM. Results indicate that a 5 mm lesion embedded in a structured breast phantom can be detected by CT breast imaging with statistically significant higher confidence than with digital mammography.

  19. Automated detection of pulmonary nodules from whole lung helical CT scans: performance comparison for isolated and attached nodules

    NASA Astrophysics Data System (ADS)

    Enquobahrie, Andinet A.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.

    2004-05-01

    The objective of this research is to evaluate and compare the performance of our automated detection algorithm on isolated and attached nodules in whole lung CT scans. Isolated nodules are surrounded by the lung parenchyma with no attachment to large solid structures such as the chest wall or mediastinum surface, while attached nodules are adjacent to these structures. The detection algorithm involves three major stages. First, the region of the image space where pulmonary nodules are to be found is identified. This involves segmenting the lung region and generating the pleural surface. In the second stage, which is the hypothesis generation stage, nodule candidate locations are identified and their sizes are estimated. The nodule candidates are successively refined in the third stage a sequence of filters of increasing complexity. The algorithm was tested on a dataset containing 250 low-dose whole lung CT scans with 2.5mm slice thickness. A scan is composed of images covering the whole lung region for a single person. The dataset was partitioned into 200 and 50 scans for training and testing the algorithm. Only solid nodules were considered in this study. Experienced chest radiologists identified a total of 447 solid nodules. 345 and 102 of the nodules were from the training and testing datasets respectively. 126(28.2%) of the nodules in the dataset were attached nodules. The detection performance was then evaluated separately for isolated and attached nodule types considering different size ranges. For nodules 3mm and larger, the algorithm achieved a sensitivity of 97.8% with 2.0 false positives (FPs) per scan and 95.7% with 19.3 FPs per scan for isolated and attached nodules respectively. For nodules 4mm and larger, a sensitivity of 96.6% with 1.5 FP per scan and a 100% sensitivity with 13 FPs per scan were obtained for isolated and attached nodule types respectively. The results show that our algorithm detects isolated and attached nodules with comparable

  20. Extended abstract: Partial row projection methods

    SciTech Connect

    Bramley, R.; Lee, Y.

    1996-12-31

    Accelerated row projection (RP) algorithms for solving linear systems Ax = b are a class of iterative methods which in theory converge for any nonsingular matrix. RP methods are by definition ones that require finding the orthogonal projection of vectors onto the null space of block rows of the matrix. The Kaczmarz form, considered here because it has a better spectrum for iterative methods, has an iteration matrix that is the product of such projectors. Because straightforward Kaczmarz method converges slowly for practical problems, typically an outer CG acceleration is applied. Definiteness, symmetry, or localization of the eigenvalues, of the coefficient matrix is not required. In spite of this robustness, work has generally been limited to structured systems such as block tridiagonal matrices because unlike many iterative solvers, RP methods cannot be implemented by simply supplying a matrix-vector multiplication routine. Finding the orthogonal projection of vectors onto the null space of block rows of the matrix in practice requires accessing the actual entries in the matrix. This report introduces a new partial RP algorithm which retains advantages of the RP methods.

  1. Cone beam CT for determining breast cancer margin: an initial experience and its comparison with mammography and specimen radiograph

    PubMed Central

    Yao, Juan; Shaw, Chris; Lai, CJ; Rong, John; Wang, Jian; Liu, Wenya

    2015-01-01

    Purpose: To assess the ability of cone beam CT (CBCT) in determining the breast cancer margin using, to compare the results with mammography and specimen radiography, and to explore the clinical potential of CBCT for breast imaging. Methods: Specimens of 46 breast cancer patients were imaged by using a prototype CBCT system. Each patient underwent mammography, CBCT and X-ray of breast surgical specimen within 6 months. Images of mammography, breast surgical specimen radiography and CBCT were evaluated by an experienced radiologist. Indicators, such as: morphology, glitch, density, invasion, structural distortion and calcification, were observed. Result: There was no significant difference of the calcification, glitch and morphology among three methods. However, there was significant difference in indicators of breast tumor invasion among three methods. There was statistical significance in detecting invasions of breast cancer cells in peripheral tissues among three methods. Conclusion: CBCT shows no superiority over mammography and specimen radiography in determining tumor’s outline and detecting calcification. On the other hand, CBCT demonstrates its advantage in determining the 3 dimensional position of a lesion which could be a potential clinical application in future practices of breast imaging. PMID:26629005

  2. Multidetector CT Enterography versus Double-Balloon Enteroscopy: Comparison of the Diagnostic Value for Patients with Suspected Small Bowel Diseases

    PubMed Central

    Guo, Qiaozhen; Zhao, Jianping; Liu, Mei; Liao, Guangquan; Chen, Nianjun; Tian, Dean; Wu, Xiaoli

    2016-01-01

    Aim. To compare the diagnostic value of multidetector CT enterography (MDCTE) and double-balloon enteroscopy (DBE) for patients with suspected small bowel diseases. Methods. From January 2009 to January 2014, 190 patients with suspected small bowel diseases were examined with MDCTE and DBE. The characteristics of the patients, detection rates, diagnostic yields, sensitivity, specificity, positive predictive value, and negative predictive value were described and analyzed. Results. The overall detection rates of DBE and MDCTE were 92.6% and 55.8%, respectively (P<0.05), while the overall diagnostic yields were 83.2% and 33.7%, respectively (P<0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of DBE were all higher than those of MDCTE. DBE had a higher diagnostic yield for OGIB (87.3% versus 20.9%, P<0.05). The diagnostic yields of DBE were higher than those of MDCTE for inflammatory diseases, angioma/angiodysplasia, and diverticulums, while being not for gastrointestinal tumors/polyps. Conclusions. The diagnostic value of DBE for small bowel diseases is better than that of MDCTE as a whole, but if gastrointestinal tumors are suspected, MDCTE is also needed to gain a comprehensive and accurate diagnosis. PMID:26962305

  3. Multidetector CT Enterography versus Double-Balloon Enteroscopy: Comparison of the Diagnostic Value for Patients with Suspected Small Bowel Diseases.

    PubMed

    Wang, Jingjing; Guo, Qiaozhen; Zhao, Jianping; Liu, Mei; Liao, Guangquan; Chen, Nianjun; Tian, Dean; Wu, Xiaoli

    2016-01-01

    Aim. To compare the diagnostic value of multidetector CT enterography (MDCTE) and double-balloon enteroscopy (DBE) for patients with suspected small bowel diseases. Methods. From January 2009 to January 2014, 190 patients with suspected small bowel diseases were examined with MDCTE and DBE. The characteristics of the patients, detection rates, diagnostic yields, sensitivity, specificity, positive predictive value, and negative predictive value were described and analyzed. Results. The overall detection rates of DBE and MDCTE were 92.6% and 55.8%, respectively (P<0.05), while the overall diagnostic yields were 83.2% and 33.7%, respectively (P<0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of DBE were all higher than those of MDCTE. DBE had a higher diagnostic yield for OGIB (87.3% versus 20.9%, P<0.05). The diagnostic yields of DBE were higher than those of MDCTE for inflammatory diseases, angioma/angiodysplasia, and diverticulums, while being not for gastrointestinal tumors/polyps. Conclusions. The diagnostic value of DBE for small bowel diseases is better than that of MDCTE as a whole, but if gastrointestinal tumors are suspected, MDCTE is also needed to gain a comprehensive and accurate diagnosis. PMID:26962305

  4. Diagnostic quality of CT pulmonary angiography in pulmonary thromboembolism: A comparison of three different kV values

    PubMed Central

    Yilmaz, Ömer; Üstün, Esma Dilek; Kayan, Mustafa; Kayan, Fatmanur; Aktaş, Aykut Recep; Unlu, Elif Nisa; Degirmenci, Bumin; Cetin, Meltem

    2013-01-01

    Background Our purpose was to evaluate the effectiveness of different kilovolt (kV) uses in computed tomography pulmonary angiography (CTPA) in the diagnosis of pulmonary thromboembolism (PTE). We also aimed to establish the optimal kV value and investigate the possibility of obtaining appropriate imaging quality with minimal radiation dose. Material/Methods We compared 120, 100, and 80 kV CTPA for 90 patients in whom PTE was clinically considered. The examinations were carried out using a 128 multislice CT device (Definition AS, Siemens Medical Solutions, Forchheim, Germany). Each kV value was used on 30 patients in 3 groups. Patients in all groups were compared with respect to the mean radiation dose they received, pulmonary arterial attenuation values, image quality, and motion artefacts. Results With respect to pulmonary arterial attenuation values, imaging with 80 kV yielded significantly higher values (p<0.05). However, no difference was found between 120 kV, 100 kV, and 80 kV with respect to image quality. Similarly, no significant difference was detected between the groups with respect to pulmonary artery contrasting and motion artefacts. Statistically significant differences were present in DLP values and effective dose among all 3 groups (p<0.001). Conclusions Using 80 kV as the low value in CTPA imaging for patients pre-diagnosed with PTE will increase the density of pulmonary arteries and decrease the amount of radiation received. PMID:24169688

  5. Image Quality of 3rd Generation Spiral Cranial Dual-Source CT in Combination with an Advanced Model Iterative Reconstruction Technique: A Prospective Intra-Individual Comparison Study to Standard Sequential Cranial CT Using Identical Radiation Dose

    PubMed Central

    Wenz, Holger; Maros, Máté E.; Meyer, Mathias; Förster, Alex; Haubenreisser, Holger; Kurth, Stefan; Schoenberg, Stefan O.; Flohr, Thomas; Leidecker, Christianne; Groden, Christoph; Scharf, Johann; Henzler, Thomas

    2015-01-01

    Objectives To prospectively intra-individually compare image quality of a 3rd generation Dual-Source-CT (DSCT) spiral cranial CT (cCT) to a sequential 4-slice Multi-Slice-CT (MSCT) while maintaining identical intra-individual radiation dose levels. Methods 35 patients, who had a non-contrast enhanced sequential cCT examination on a 4-slice MDCT within the past 12 months, underwent a spiral cCT scan on a 3rd generation DSCT. CTDIvol identical to initial 4-slice MDCT was applied. Data was reconstructed using filtered backward projection (FBP) and 3rd-generation iterative reconstruction (IR) algorithm at 5 different IR strength levels. Two neuroradiologists independently evaluated subjective image quality using a 4-point Likert-scale and objective image quality was assessed in white matter and nucleus caudatus with signal-to-noise ratios (SNR) being subsequently calculated. Results Subjective image quality of all spiral cCT datasets was rated significantly higher compared to the 4-slice MDCT sequential acquisitions (p<0.05). Mean SNR was significantly higher in all spiral compared to sequential cCT datasets with mean SNR improvement of 61.65% (p*Bonferroni0.05<0.0024). Subjective image quality improved with increasing IR levels. Conclusion Combination of 3rd-generation DSCT spiral cCT with an advanced model IR technique significantly improves subjective and objective image quality compared to a standard sequential cCT acquisition acquired at identical dose levels. PMID:26288186

  6. CT of nontraumatic thoracic aortic emergencies.

    PubMed

    Bhalla, Sanjeev; West, O Clark

    2005-10-01

    Computed tomography (CT), especially multidetector row CT (MDCT), is often the preferred imaging test used for evaluation of nontraumatic thoracic aortic abnormalities. Unenhanced images, usually followed by contrast-enhanced arterial imaging, allow for rapid detailed aortic assessment. Understanding the spectrum of acute thoracic aortic conditions which may present similarly (aortic dissection, aneurysm rupture, penetrating atherosclerotic ulcer, intramural hematoma) will ensure that patients are diagnosed and treated appropriately. Familiarity with imaging protocols and potential mimics will prevent confusion of normal anatomy and variants with aortic disease. PMID:16274000

  7. The RowPerfect ergometer: a training aid for on-water single scull rowing.

    PubMed

    Elliott, Bruce; Lyttle, Andrew; Birkett, Olivia

    2002-07-01

    The purpose of this study was to compare rowing technique on the dynamic RowPerfect ergometer with a single scull. Eight national-level rowers performed on both the RowPerfect ergometer and in a single scull over 500 m, at rates of 24, 26, and 28 strokes/minute. Blade force and oar angle (on-water) and handle force and stroke length (on the ergometer) were measured. Both force and stroke angle/length were normalised from 0 to 100 (where 100 was the peak value). Body positions of the subjects at both the catch and finish of each of these rowing strokes were also compared for each stroke rate. The coefficient of multiple determination (CMD) was used to measure the consistency of force curves over a sample of five sequential strokes for each rower. Cross-correlations were performed between the left- and right-side on-water sculling force curves and a mean of these values with the ergometer curve for each rower. Stroke angle/length, which did not vary with rate, was similar for both forms of rowing. The CMDs showed a high consistency across the normalised strokes of each subject (approximately 0.98). Cross-correlation values of 0.91, 0.92, and 0.93 were recorded between the force curves from the ergometer and on-water trials for stroke rates of 24, 26, and 28 strokes/minute, respectively. The mean trunk, thigh and lower leg angles at the catch and finish of the stroke were also similar across the stroke rates as determined by t-tests. Results indicate that technique used on the RowPerfect ergometer was similar to that for on-water sculling, thus validating its use in off-water training. PMID:14658370

  8. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial ... or other growth (mass) Cerebral atrophy (loss of brain tissue) ... with the hearing nerve Stroke or transient ischemic attack (TIA)

  9. Principle and applications of dual source CT

    NASA Astrophysics Data System (ADS)

    Flohr, Thomas

    2008-08-01

    Dual source CT (DSCT) has the potential to solve remaining limitations of conventional multi-detector row CT (MDCT)-scanners, such as insufficient temporal resolution for ECG-controlled cardiac imaging. A DSCT is equipped with two X-ray tubes and two corresponding detectors that are mounted onto the rotating gantry with an angular offset of 90°. The key benefit of DSCT for cardiac scanning is improved temporal resolution equivalent to a quarter of the gantry rotation time (83 ms at 0.33 s rotation time). Additionally, both X-ray tubes can be operated at different kV- and mA-settings, enabling the acquisition of dual energy data. The acquisition of dual energy CT data can add functional information to the morphological information based on different X-ray attenuation coefficients that is usually obtained in a CT examination.

  10. Reliability and validity of the modified Conconi test on concept II rowing ergometers.

    PubMed

    Celik, Ozgür; Koşar, Sükran Nazan; Korkusuz, Feza; Bozkurt, Murat

    2005-11-01

    The purpose of this study was to assess the reliability and validity of the modified Conconi test on Concept II rowing ergometers. Twenty-eight oarsmen conducted 3 performance tests on separate days. Reliability was assessed using the break point in heart rate (HR) linearity called the Conconi test (CT) and Conconi retest (CRT) for the noninvasive measurement of anaerobic threshold (AT). Blood lactate measurement was considered the gold standard for the assessment of the AT, and the validity of the CT was assessed by blood samples taken during an incremental load test (ILT) on ergometers. According to the results, the mean power output (PO) scores for the CT, CRT, and ILT were 234.2 +/- 40.3 W, 232.5 +/- 39.7 W, and 229.7 +/- 39.6 W, respectively. The mean HR values at the AT for the CT, CRT, and ILT were 165.4 +/- 11.2 b.min, 160.4 +/- 10.8 b.min, and 158.3 +/- 8.8 b.min, respectively. Interclass correlation coefficient (ICC) analysis indicated a significant correlation between the 3 tests with one another. Also, Bland and Altman plots showed that there was an association between noninvasive tests and the ILT PO scores and HRs (95% confidence interval [CI]). In conclusion, this study showed that the modified CT is a reliable and valid method for determining the AT of elite men rowers. PMID:16287355

  11. Comparison of Fusion Imaging Using a Combined SPECT/CT System and Intra-arterial CT: Assessment of Drug Distribution by an Implantable Port System in Patients Undergoing Hepatic Arterial Infusion Chemotherapy

    SciTech Connect

    Ikeda, Osamu Kusunoki, Shinichiroh; Nakaura, Takeshi; Shiraishi, Shinya; Kawanaka, Kouichi; Tomiguchi, Seiji; Yamashita, Yasuyuki; Takamori, Hiroshi; Chikamoto, Akira; Kanemitsu, Keiichiro

    2006-06-15

    Hepatic arterial infusion (HAI) chemotherapy is effective for treating primary and metastatic carcinoma of the liver. We compared the perfusion patterns of HAI chemotherapy on intra-arterial port-catheter computed tomography (iapc-CT) and fused images obtained with a combined single-photon emission computed tomography/computed tomography (SPECT/CT) system. We studied 28 patients with primary or metastatic carcinoma of the liver who bore an implantable HAI port system. All underwent abdominal SPECT using Tc-99m-MAA (185 Mbq); the injection rate was 1 mL/min, identical to the chemotherapy infusion rate, and 0.5 mL/sec for iapc-CT. Delivery was through an implantable port. We compared the intrahepatic perfusion (IHP) and extrahepatic perfusion (EHP) patterns of HAI chemotherapy on iapc-CT images and fused images obtained with a combined SPECT/CT system. In 23 of 28 patients (82%), IHP patterns on iapc-CT images and fused images were identical. In 5 of the 28 patients (18%), IHP on fusion images was different from IHP on iapc-CT images. EHP was seen on fused images in 12 of the 28 patients (43%) and on iapc-CT images in 8 patients (29%). In 17 patients (61%), upper gastrointestinal endoscopy revealed gastroduodenal mucosal lesions. EHP was revealed on fused images in 10 of these patients; 9 of them manifested gastroduodenal toxicity at the time of subsequent HAI chemotherapy. Fusion imaging using the combined SPECT/CT system reflects the actual distribution of the infused anticancer agent. This information is valuable not only for monitoring adequate drug distribution but also for avoiding potential extrahepatic complications.

  12. Peri-infarct ischaemia assessed by cardiovascular MRI: comparison with quantitative perfusion single photon emission CT imaging

    PubMed Central

    Cochet, H; Bullier, E; Ragot, C; Gilbert, S H; Pucheu, Y; Laurent, F; Coste, P; Bordenave, L; Montaudon, M

    2014-01-01

    Objective: To develop a new method for the cardiac MR (CMR) quantification of peri-infarct ischaemia using fused perfusion and delayed–enhanced images and to evaluate this method using quantitative single photon emission CT (SPECT) imaging as a reference. Methods: 40 patients presenting with peri-infarct ischaemia on a routine stress 99mTc-SPECT imaging were recruited. Within 8 days of the SPECT study, myocardial perfusion was evaluated using stress adenosine CMR. Using fused perfusion and delayed–enhanced images, peri-infarct ischaemia was quantified as the percentage of myocardium with stress-induced perfusion defect that was adjacent to and larger than a scar. This parameter was compared with both the percent myocardium ischaemia (SD%) and the ischaemic total perfusion deficit (TPD). The diagnostic performance of CMR in detection of significant coronary artery stenosis (of ≥70%) was also determined. Results: On SPECT imaging, in addition to peri-infarct ischaemia, reversible perfusion abnormalities were detected in a remote zone in seven patients. In the 33 patients presenting with only peri-infarct ischaemia, the agreement between CMR peri-infarct ischaemia and both SD% and ischaemic TPD was excellent [intraclass coefficient of correlation (ICC) = 0.969 and ICC = 0.877, respectively]. CMR-defined peri-infarct ischaemia for the detection of a significant coronary artery stenosis showed an areas under receiver–operating characteristic curve of 0.856 (95% confidence interval, 0.680–0.939). The best cut-off value was 8.1% and allowed a 72% sensitivity, 96% specificity, 60% negative predictive value and 97% positive predictive value. Conclusion: This proof-of-concept study shows that CMR imaging has the potential as a test for quantification of peri-infarct ischaemia. Advances in knowledge: This study demonstrates the proof of concept of a commonly known intuitive idea, that is, evaluating the peri-infarct ischaemic burden by subtracting delayed

  13. Hand Replantation with Proximal Row Carpectomy

    PubMed Central

    Lee, Young-Keun; Lee, Hang-Ho; Park, Ji-Kang; Kim, Joo-Yong; Dhawan, Vikas

    2008-01-01

    The purpose of this study is to present our operative technique and postoperative results of the hand replantation with proximal row carpectomy in cases of complete amputation at the level of wrist joint. From May 2003 to April 2005, five patients suffered from complete amputation of the hand due to industrial trauma. Amputation level was radiocarpal joint in three cases and midcarpal joint in two cases. Three cases represented guillotine type and two cases with local crush type injuries. All were men and the mean age was 26.6 years. The mean follow-up period was 26.8 months. At the time of replantation, the wrist joint was stabilized with transarticular fixation using three to four Kirschner’s wires after performing proximal row carpectomy. Postoperatively, functional results such as muscle strength, range of motion of the wrist and fingers, and sensory recovery were assessed according to Chen’s criteria. Joint width and arthritic changes of the radio-capitate joint were evaluated with radiologic tools. According to Chen’s criteria, the overall results in five cases were classified as grade II. Intrinsic muscle power of hands was found to be grade 4. The mean grip and pinch powers were 41% and 45%, respectively, compared to contralateral hand. The mean arc of flexion–extension of wrist was 53°. Total mean active motion of fingers was 215 degrees. Static two-point discrimination of fingertip ranged from 8 to 13 mm. On the follow-up, computerized tomography showed well-preserved radio-capitate joint space without any arthritic changes. While performing hand replantation after amputation at the radiocarpal or midcarpal level, proximal row carpectomy is a useful procedure to preserve joint motion of the wrist in selected cases. PMID:18855073

  14. Rowing prevents muscle wasting in older men.

    PubMed

    Yoshiga, Chie C; Higuchi, Mitsuru; Oka, Jun

    2002-11-01

    We evaluated the effects of rowing on the morphology and function of the leg extensor muscle in old people. The area and the power of the leg extensor muscle were measured in 15 oarsmen--age [mean (SD)] 65 (3) years; height 171 (4) cm, body mass 68 (6) kg--and in 15 sedentary men--age 66 (4) years, height 170 (4) cm, body mass 67 (7) kg--who were matched on the basis of their body size. The leg extensor muscle area of the oarsmen was larger than that of the sedentary men [77.8 (5.4) vs 68.4 (5.1) cm(2), P < 0.05]. Also the bilateral leg extension power of the oarsmen was larger than that of the sedentary men [1,624 (217) vs 1,296 (232) W, P < 0.05]. Thus, the leg extension power per the leg extensor muscle area was not significantly different between two groups [20.9 (2.0) vs 19.9 (2.1) W x cm(-2)) and leg extension power was correlated to the leg extensor muscle area (59-89 cm(2), r = 0.74, P < 0.001). Also the 2,000-m rowing ergometer time of the oarsmen [495 (14) s; range 479-520 s] was related to leg extensor muscle area (68-89 cm(2), r = 0.63, P < 0.01). The results suggest that rowing prevents age-related muscle wasting and weakness. PMID:12436264

  15. CT-Based Evaluation of Tumor Volume After Intra-Arterial Chemotherapy of Locally Advanced Carcinoma of the Oral Cavity: Comparison with Clinical Remission Rates

    SciTech Connect

    Rohde, Stefan Turowski, Bernd; Berkefeld, Joachim; Kovacs, Adorjan F.

    2007-02-15

    Purpose. To assess the volume of locally advanced tumors of the oral cavity and the oropharynx before and after intra-arterial (i.a.) chemotherapy by means of computed tomography and to compare these data with clinically determined treatment response of the same patient population. Methods. Eighty-eight patients with histologically proven, advanced carcinoma of the oral cavity and/or the oropharynx (local tumor stages T3/4) received neoadjuvant i.a. chemotherapy with cisplatin as part of a multimodal therapeutic regimen, comprising (1) local chemotherapy, (2) surgery, and (3) combined radio-chemotherapy. Three weeks after the intervention, residual disease was evaluated radiologically by measurement of the tumor volume and clinically by inspection and palpation of the primary tumor according to WHO criteria. Results. Comparison of treatment response according to radiological and clinical criteria respectively revealed complete remission in 5% vs. 8% (p < 0.05), partial remission in 30% vs. 31%, stable disease in 61% vs. 58%, and tumor progression in 5% vs. 2%. Conclusion. Radiological volumetry and clinical evaluation found comparable response rates after local chemotherapy. However, in patients with good response after local treatment, volumetric measurement with CT may help to distinguish between partial and complete remission. Thus, radiological tumor volumetry provides precise and differentiated information about tumor response and should be used as an additional tool in treatment monitoring after local chemotherapy.

  16. Comparing single-row and twin-row corn production in the mid south

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigated corn (Zea mays L.) was grown at Stoneville, MS in single-and twin-rows at 27 032, 32 312, 36 833, and 41 217 plants/A and N-fertilizer rates of 180, 220, and 260 lbs N/A. Stands, leaf area index (LAI), yield, test weight, 100-kernel weight, lodging, and mycotoxins were determined. LAI was...

  17. 97. VIEW OF CENTER OF INTERIOR ROW OF EQUIPMENT CABINETS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    97. VIEW OF CENTER OF INTERIOR ROW OF EQUIPMENT CABINETS ON SOUTH SIDE OF LANDLINE INSTRUMENTATION ROOM. THREE ADDITIONAL GOULD BRUSH CHART RECORDERS ARE IN THIS ROW (NOT VISIBLE IN PHOTOGRAPH) LOCATED IMMEDIATELY EAST (LEFT) OF THESE CABINETS. Another row of cabinets south of (behind) this one is not accessible for photography. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  18. A New Submaximal Rowing Test to Predict 2,000-m Rowing Ergometer Performance.

    PubMed

    Otter, Ruby T A; Brink, Michel S; Lamberts, Robert P; Lemmink, Koen A P M

    2015-09-01

    The purpose of this study was to assess predictive value of a new submaximal rowing test (SmRT) on 2,000-m ergometer rowing time-trial performance in competitive rowers. In addition, the reliability of the SmRT was investigated. Twenty-four competitive male rowers participated in this study. After determining individual HRmax, all rowers performed an SmRT followed by a 2,000-m rowing ergometer time trial. In addition, the SmRT was performed 4 times (2 days in between) to determine the reliability. The SmRT consists of two 6-minute stages of rowing at 70 and 80% HRmax, followed by a 3-minute stage at 90% HRmax. Power was captured during the 3 stages, and 60 seconds of heart rate recovery (HRR60s) was measured directly after the third stage. Results showed that predictive value of power during the SmRT on 2,000-m rowing time also increased with stages. CVTEE% is 2.4, 1.9, and 1.3%. Pearson correlations (95% confidence interval [95% CI]) were -0.73 (-0.88 to -0.45), -0.80 (-0.94 to -0.67), and -0.93 (-0.97 to -0.84). 2,000-m rowing time and HRR60s showed no relationship. Reliability of power during the SmRT improved with the increasing intensity of the stages. The coefficient of variation (CVTEM%) was 9.2, 5.6, and 0.4%. Intraclass correlation coefficients (ICC) and 95% CI were 0.91 (0.78-0.97), 0.92 (0.81-0.97), and 0.99 (0.97-1.00). The CVTEM% and ICC of HRR60s were 8.1% and 0.93 (0.82-0.98). In conclusion, the data of this study shows that the SmRT is a reliable test that it is able to accurately predict 2,000-m rowing time on an ergometer. The SmRT is a practical and valuable submaximal test for rowers, which can potentially assist with monitoring, fine-tuning and optimizing training prescription in rowers. PMID:25774627

  19. Comparison of the effects of salmon calcitonin (sCT) and calcitonin gene-related peptide (CGRP) in a number of in vivo and in vitro tests

    SciTech Connect

    Welch, S.P.; Brase, D.; Cooper, C.; Dewey, W.L.

    1986-03-05

    sCT and CGRP have been shown previously to have multiple activities in the central nervous system (CNS). Recent work has shown that CGRP (15 ..mu..g) intraventricularly (IVT) produces a naloxone reversible 37% inhibition in the p-phenylquinone test (PPQ) accompanied by severe diarrhea. The ED50 of sCT in the PPQ test is 362 ng and this effect is not reversed totally by naloxone. The onset of CGRP is more rapid than that of sCT. sCT and CGRP (10/sup -6/M) both produce naloxone reversible inhibition of the electrically stimulated guinea pig ileum (GPI) (25% and 50% respectively). Both sCT and CGRP (10/sup -6/ M) produce contracture (15% and 40% respectively) of the non-stimulated GPI that is not blocked by atropine. Both sCT and CGRP block the naloxone-induced contracture of the morphine (MS04) dependent ilea (29% and 68% respectively). Both sCT and CGRP produce biphasic shifts in the MS04 acetylcholine dose-effect curves in the stimulated and nonstimulated GPI, respectively. Neither sCT nor CGRP (10/sup -9/ to 10/sup -4/ M) displaces /sup 3/H-naloxone binding to mouse brain membranes. Both sCT and CGRP may produce their effects by modulation of CA/sup +2/ fluxes in the CNS and GPI.

  20. Three-dimensional texture analysis of contrast enhanced CT images for treatment response assessment in Hodgkin lymphoma: Comparison with F-18-FDG PET

    SciTech Connect

    Knogler, Thomas; El-Rabadi, Karem; Weber, Michael; Karanikas, Georgios; Mayerhoefer, Marius E.

    2014-12-15

    Purpose: To determine the diagnostic performance of three-dimensional (3D) texture analysis (TA) of contrast-enhanced computed tomography (CE-CT) images for treatment response assessment in patients with Hodgkin lymphoma (HL), compared with F-18-fludeoxyglucose (FDG) positron emission tomography/CT. Methods: 3D TA of 48 lymph nodes in 29 patients was performed on venous-phase CE-CT images before and after chemotherapy. All lymph nodes showed pathologically elevated FDG uptake at baseline. A stepwise logistic regression with forward selection was performed to identify classic CT parameters and texture features (TF) that enable the separation of complete response (CR) and persistent disease. Results: The TF fraction of image in runs, calculated for the 45° direction, was able to correctly identify CR with an accuracy of 75%, a sensitivity of 79.3%, and a specificity of 68.4%. Classical CT features achieved an accuracy of 75%, a sensitivity of 86.2%, and a specificity of 57.9%, whereas the combination of TF and CT imaging achieved an accuracy of 83.3%, a sensitivity of 86.2%, and a specificity of 78.9%. Conclusions: 3D TA of CE-CT images is potentially useful to identify nodal residual disease in HL, with a performance comparable to that of classical CT parameters. Best results are achieved when TA and classical CT features are combined.

  1. Kilovoltage cone-beam CT imaging dose during breast radiotherapy: A dose comparison between a left and right breast setup

    SciTech Connect

    Quinn, Alexandra; Holloway, Lois; Begg, Jarrad; Nelson, Vinod; Metcalfe, Peter

    2014-07-01

    The purpose of this study was to investigate the delivered dose from a kilovoltage cone-beam computed tomography (kV-CBCT) acquired in breast treatment position for a left and right breast setup. The dose was measured with thermoluminescent dosimeters positioned within a female anthropomorphic phantom at organ locations. Imaging was performed on an Elekta Synergy XVI system with the phantom setup on a breast board. The image protocol involved 120 kVp, 140 mAs, and a 270° arc rotation clockwise 0° to 270° for the left breast setup and 270° to 180° for the right breast setup (maximum arc rotations possible). The dose delivered to the left breast, right breast, and heart was 5.1 mGy, 3.9 mGy, and 4.0 mGy for the left breast setup kV-CBCT, and 6.4 mGy, 6.0 mGy, and 4.8 mGy for the right breast setup kV-CBCT, respectively. The rotation arc of the kV-CBCT influenced the dose delivered, with the right breast setup kV-CBCT found to deliver a dose of up to 4 mGy or 105% higher to the treated breast′s surface in comparison with the left breast setup. This is attributed to the kV-CBCT source being more proximal to the anterior of the phantom for a right breast setup, whereas the source is more proximal to the posterior of the patient for a left-side scan.

  2. Kilovoltage cone-beam CT imaging dose during breast radiotherapy: a dose comparison between a left and right breast setup.

    PubMed

    Quinn, Alexandra; Holloway, Lois; Begg, Jarrad; Nelson, Vinod; Metcalfe, Peter

    2014-01-01

    The purpose of this study was to investigate the delivered dose from a kilovoltage cone-beam computed tomography (kV-CBCT) acquired in breast treatment position for a left and right breast setup. The dose was measured with thermoluminescent dosimeters positioned within a female anthropomorphic phantom at organ locations. Imaging was performed on an Elekta Synergy XVI system with the phantom setup on a breast board. The image protocol involved 120kVp, 140mAs, and a 270° arc rotation clockwise 0° to 270° for the left breast setup and 270° to 180° for the right breast setup (maximum arc rotations possible). The dose delivered to the left breast, right breast, and heart was 5.1mGy, 3.9mGy, and 4.0mGy for the left breast setup kV-CBCT, and 6.4mGy, 6.0mGy, and 4.8mGy for the right breast setup kV-CBCT, respectively. The rotation arc of the kV-CBCT influenced the dose delivered, with the right breast setup kV-CBCT found to deliver a dose of up to 4mGy or 105% higher to the treated breast's surface in comparison with the left breast setup. This is attributed to the kV-CBCT source being more proximal to the anterior of the phantom for a right breast setup, whereas the source is more proximal to the posterior of the patient for a left-side scan. PMID:24630912

  3. Configuring bonds between first-row transition metals.

    PubMed

    Eisenhart, Reed J; Clouston, Laura J; Lu, Connie C

    2015-11-17

    Alfred Werner, who pioneered the field of coordination chemistry, envisioned coordination complexes as a single, transition metal atom at the epicenter of a vast ligand space. The idea that the locus of a coordination complex could be shared by multiple metals held together with covalent bonds would eventually lead to the discovery of the quadruple and quintuple bond, which have no analogues outside of the transition metal block. Metal-metal bonding can be classified into homometallic and heterometallic groups. Although the former is dominant, the latter is arguably more intriguing because of the inherently larger chemical space in which metal-metal bonding can be explored. In 2013, Lu and Thomas independently reported the isolation of heterometallic multiple bonds with exclusively first-row transition metals. Structural and theoretical data supported triply bonded Fe-Cr and Fe-V cores. This Account describes our continued efforts to configure bonds between first-row transition metals from titanium to copper. Double-decker ligands, or binucleating platforms that brace two transition metals in proximity, have enabled the modular synthesis of diverse metal-metal complexes. The resulting complexes are also ideal for investigating the effects of an "ancillary" metal on the properties and reactivities of an "active" metal center. A total of 38 bimetallic complexes have been compiled comprising 18 unique metal-metal pairings. Twenty-one of these bimetallics are strictly isostructural, allowing for a systematic comparison of metal-metal bonding. The nature of the chemical bond between first-row metals is remarkably variable and depends on two primary factors: the total d-electron count, and the metals' relative d-orbital energies. Showcasing the range of covalent bonding are a quintuply bonded (d-d)(10) Mn-Cr heterobimetallic and the singly bonded late-late pairings, e.g., Fe-Co, which adopt unusually high spin states. A long-term goal is to rationally tailor the

  4. Comparison of organ-specific-radiation dose levels between 70 kVp perfusion CT and standard tri-phasic liver CT in patients with hepatocellular carcinoma using a Monte-Carlo-Simulation-based analysis platform

    PubMed Central

    Gawlitza, J.; Haubenreisser, H.; Meyer, M.; Hagelstein, C.; Sudarski, S.; Schoenberg, S.O.; Henzler, T.

    2016-01-01

    Purpose The aim of this study was to systematically compare organ-specific-radiation dose levels between a radiation dose optimized perfusion CT (dVPCT) protocol of the liver and a tri-phasic standard CT protocol of the liver using a Monte-Carlo-Simulation-based analysis platform. Methods and materials The complete CT data of 52 patients (41 males; mean age 65 ± 12) with suspected HCC that underwent dVPCT examinations on a 3rd generation dual-source CT (Somatom Force, Siemens) with a dose optimized tube voltage of 70 kVp or 80 kVp were exported to an analysis platform (Radimetrics, Bayer). The dVPCT studies were matched with a reference group of 50 patients (35 males; mean age 65 ± 14) that underwent standard tri-phasic CT (sCT) examinations of the liver with 130 kVp using the calculated water-equivalent-diameter of the patients. The analysis platform was used for the calculation of the organ-specific effective dose (ED) as well as global radiation-dose parameters (ICRP103). Results The organ-specific ED of the dVPCT protocol was statistically significantly lower when compared to the sCT in 14 of 21, and noninferior in a total of 18 of 21 examined items (all p < 0.05). The EDs of the dVPCT examinations were especially in the dose sensitive organs such as the red marrow (17.3 mSv vs 24.6 mSv, p = < 0.0001) and the liver (33.3 mSv vs 46.9 mSv, p = 0.0003) lower when compared to the sCT. Conclusion Our results suggest that dVPCT performed at 70 or 80 kVp compares favorably to sCT performed with 130 kVp with regard to effective organ dose levels, especially in dose sensitive organs, while providing additional functional information which is of paramount importance in patients undergoing novel targeted therapies. PMID:27200404

  5. Low-dose interpolated average CT for attenuation correction in cardiac PET/CT

    NASA Astrophysics Data System (ADS)

    Wu, Tung-Hsin; Zhang, Geoffrey; Wang, Shyh-Jen; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Huang, Tzung-Chi

    2010-07-01

    Because of the advantages in the use of high photon flux and thus the short scan times of CT imaging, the traditional 68Ge scans for positron emission tomography (PET) image attenuation correction have been replaced by CT scans in the modern PET/CT technology. The combination of fast CT scan and slow PET scan often causes image misalignment between the PET and CT images due to respiration motion. Use of the average CT derived from cine CT images is reported to reduce such misalignment. However, the radiation dose to patients is higher with cine CT scans. This study introduces a method that uses breath-hold CT images and their interpolations to generate the average CT for PET image attenuation correction. Breath-hold CT sets are taken at end-inspiration and end-expiration. Deformable image registration is applied to generate a voxel-to-voxel motion matrix between the two CT sets. The motion is equally divided into 5 steps from inspiration to expiration and 5 steps from expiration to inspiration, generating a total of 8 phases of interpolated CT sets. An average CT image is generated from all the 10 phase CT images, including original inhale/exhale CT and 8 interpolated CT sets. Quantitative comparison shows that the reduction of image misalignment artifacts using the average CT from the interpolation technique for PET attenuation correction is at a similar level as that using cine average CT, while the dose to the patient from the CT scans is reduced significantly. The interpolated average CT method hence provides a low dose alternative to cine CT scans for PET attenuation correction.

  6. Quantification and elimination of windmill artifacts in multi slice CT

    NASA Astrophysics Data System (ADS)

    Utrup, Steven J.; Brown, Kevin M.

    2008-03-01

    In multi-slice cone beam CT imaging, there are artifacts known as windmill artifacts. These artifacts are due to not satisfying the Nyquist criteria in the patient longitudinal direction. This paper quantifies and compares these artifacts as a function of the number of rows, pitch, collimation, and image thickness of the CT scanner. Scanners with rows of 16, 64 and 128 are measured and compared with simulated data, using both Helical and Axial scanning modes. In addition three focal spot switching modes are compared: the traditional within image plane mode; diagonal mode; and quad mode. All images are compared via four criteria: artifacts, MTF, SSP and noise. Results show that the frequency of the artifact, or number of blades on the windmill and magnitude of each blade, is dependent on the rate at which the rows are crossed for an image. For example, for a given pitch, doubling the rows doubles the frequency of the artifact, with each artifact approximately the magnitude. A similar result can be obtained by keeping the number of rows constant and varying the pitch. The artifact disappears as the Nyquist criteria is satisfied by either increasing the slice thickness or incorporating one of the focal spot switching modes that switch in the patient longitudinal direction. For a given MTF and SSP, the diagonal focal spot switching mode has slightly more noise while the other two are approximately equal. The artifact varies with the quad mode being the best and traditional mode being the worse.

  7. High-resolution CT by diffraction-enhanced x-ray imaging: mapping of breast tissue samples and comparison with their histo-pathology.

    PubMed

    Bravin, Alberto; Keyriläinen, Jani; Fernández, Manuel; Fiedler, Stefan; Nemoz, Christian; Karjalainen-Lindsberg, Marja-Liisa; Tenhunen, Mikko; Virkkunen, Pekka; Leidenius, Marjut; von Smitten, Karl; Sipilä, Petri; Suortti, Pekka

    2007-04-21

    The aim of this study was to introduce high-resolution computed tomography (CT) of breast tumours using the diffraction-enhanced x-ray imaging (DEI) technique and to compare results with radiological and histo-pathological examinations. X-ray CT images of tumour-bearing breast tissue samples were acquired by monochromatic synchrotron radiation (SR). Due to the narrow beam and a large sample-to-detector distance scattering is rejected in the absorption contrast images (SR-CT). Large contrast enhancement is achieved by the use of the DEI-CT method, where the effects of refraction and scatter rejection are analysed by crystal optics. Clinical mammograms and CT images were recorded as reference material for a radiological examination. Three malignant and benign samples were studied in detail. Their radiographs were compared with optical images of stained histological sections. The DEI-CT images map accurately the morphology of the samples, including collagen strands and micro-calcifications of dimensions less than 0.1 mm. Histo-pathological examination and reading of the radiographs were done independently, and the conclusions were in general agreement. High-resolution DEI-CT images show strong contrast and permit visualization of details invisible in clinical radiographs. The radiation dose may be reduced by an order of magnitude without compromising image quality, which would make possible clinical in vivo DEI-CT with future compact SR sources. PMID:17404464

  8. High bone turnover assessed by 18F-fluoride PET/CT in the spine and sacroiliac joints of patients with ankylosing spondylitis: comparison with inflammatory lesions detected by whole body MRI

    PubMed Central

    2012-01-01

    Background This study compares the frequency and distribution of increased activity on 18 F-fluoride PET/CT with the presence of bone marrow edema on whole-body MR imaging in the spine and sacroiliac joints (SIJ) of patients with active ankylosing spondylitis (AS). Methods Ten patients (6 men and 4 women), between 30 and 58 years old (median 44) with active AS, were prospectively examined with both whole-body MRI and 18 F-fluoride PET/CT. Patients fulfilled modified NY criteria and had a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) of at least 4. Increased radiotracer uptake in PET/CT and bone marrow edema in whole-body MRI of spine and SIJ was evaluated independently by two blinded observers for each modality. Kappa statistics were used to compare interobserver agreement as well as scores of consensus reading of the two imaging modalities. Results Analysis of interobserver agreement for PET/CT yielded a kappa value of 0.68 for spinal lesions and of 0.88 for SIJ lesions. The corresponding kappa values for the MRI modality were 0.64 and 0.93, respectively. More spinal lesions were detected by MRI in comparison to PET/CT (68 vs. 38), whereas a similar number of SIJ quadrants scored positive in both modalities (19 vs. 17). Analysis of agreement of lesion detection between both imaging modalities yielded a kappa value of only 0.25 for spinal lesions and of 0.64 for SIJ lesions. Conclusion Increased 18 F-fluoride uptake in PET/CT is only modestly associated with bone marrow edema on MRI in the spine and SIJ of patients with AS, suggesting different aspects of bone involvement in AS. PMID:22788874

  9. Comparison of SPECT/CT and MRI in Diagnosing Symptomatic Lesions in Ankle and Foot Pain Patients: Diagnostic Performance and Relation to Lesion Type

    PubMed Central

    Ha, Seunggyun; Hong, Sung Hwan; Paeng, Jin Chul; Lee, Dong Yeon; Cheon, Gi Jeong; Arya, Amitabh; Chung, June-Key; Lee, Dong Soo; Kang, Keon Wook

    2015-01-01

    Purpose The purpose of this study was to compare the diagnostic performance of SPECT/CT and MRI in patients with ankle and foot pain, with regard to the lesion types. Materials and Methods Fifty consecutive patients with ankle and foot pain, who underwent 99mTc-MDP SPECT/CT and MRI, were retrospectively enrolled in this study. Symptomatic lesions were determined based on clinical examination and response to treatment. On MRI and SPECT/CT, detected lesions were classified as bone, ligament/tendon, and joint lesions. Uptake on SPECT/CT was assessed using a 4-grade system. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of SPECT/CT and MRI were evaluated in all detected lesions and each lesion type. Diagnostic value of uptake grade was analyzed using receiver-operating characteristics (ROC) curve analysis, and diagnostic performance was compared using Chi-square or McNemar tests. Results In overall lesions, the sensitivity, PPV and NPV of SPECT/CT for symptomatic lesions were 93%, 56%, 91%, and they were 98%, 48%, 95% for MRI. There was no significant difference between SPECT/CT and MRI. However, the specificity of SPECT/CT was significantly higher than that of MRI (48% versus 24%, P = 0.016). Uptake grade on SPECT/CT was significantly higher in symptomatic lesions (P < 0.001), and its area under curve on ROC analysis was 0.787. In the analysis of each lesion type, the specificity of SPECT/CT was poor in joint lesions compared with other lesion types and MRI (P < 0.001, respectively). MRI exhibited lower specificity than SPECT/CT in bone lesions (P = 0.004) and ligament/tendon lesions (P < 0.001). Conclusions SPECT/CT has MRI-comparable diagnostic performance for symptomatic lesions in ankle and foot pain patients. SPECT/CT and MRI exhibit different diagnostic specificity in different lesion types. SPECT/CT may be used as a complementary imaging method to MRI for enhancing diagnostic specificity. PMID:25668182

  10. Comparison of cone beam CT scans with enhanced photostimulated phosphor plate images in the detection of root fracture of endodontically treated teeth

    PubMed Central

    Bechara, B; McMahan, C A; Noujeim, M; Faddoul, T; Moore, W S; Teixeira, F B; Geha, H

    2013-01-01

    Objectives: Two-dimensional intraoral radiography is the most common tool for diagnosing root fractures (RFs). Cone beam CT (CBCT) is widely used to depict RFs in endodontically treated teeth. Beam hardening and other artefacts caused by gutta percha may result in an incorrect diagnosis when using CBCT only. A comparison of two CBCT machines with photostimulated phosphor (PSP) plate images enhanced with the equalization tool was carried out to detect RFs in endodontically treated teeth. Methods: 66 roots were collected, decoronated and treated endodontically using the same technique with gutta percha. 33 of these roots were randomly selected and fractured; the 2 root fragments were glued together with 1 layer of methyl methacrylate and placed randomly in 8 prepared beef rib fragments. Large fields of view (FOVs) were acquired with one CBCT unit and small FOVs with the second CBCT unit. Periapical radiographs (using intraoral PSP plates) were also acquired. A contrast enhancement tool was used when evaluating the PSP plate images. Results: Small FOV images had significantly higher accuracy (area under the receiver operating characteristic curve) and sensitivity in detecting RFs than PSP plates and large FOV images. The specificity of the enhanced PSP images was higher than, although not significantly higher than, the small FOV images and was significantly higher than the large FOV images. Conclusions: CBCT small FOVs should be acquired for depicting RFs of endodontically treated teeth. Images obtained using PSP plates had the lowest rate of false-positive results and their use can save the patient a radiation dose. PMID:23625067

  11. Effect of corn or soybean row position on soil water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop plants can funnel water to the soil and increase water content more in the row relative to the interrow. Because the row intercepts more soil water after rains and higher root density, the soil may also dry out more between rains than does soil in the interrow. The purpose of this study was to ...

  12. 19. VIEW OF THE TWO ROWS OF COKE OVENS, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. VIEW OF THE TWO ROWS OF COKE OVENS, LOOKING EAST. THE OVENS LIE TO THE EAST OF THE MINE BUILDINGS. BEEHIVE OVENS FORM THE ROW ON THE LEFT OF THE PHOTOGRAPH. THE RECTANGULAR OVENS ARE ON THE RIGHT. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

  13. Instability characteristics of fluidelastic instability of tube rows in crossflow

    SciTech Connect

    Chen, S.S.; Jendrzejczyk, J.A.

    1986-04-01

    An experimental study is reported to investigate the jump phenomenon in critical flow velocities for tube rows with different pitch-to-diameter ratios and the excited and intrinsic instabilities for a tube row with a pitch-to-diameter ratio of 1.75. The experimental data provide additional insights into the instability phenomena of tube arrays in crossflow. 9 refs., 10 figs.

  14. Myocardial Extracellular Volume Fraction with Dual-Energy Equilibrium Contrast-enhanced Cardiac CT in Nonischemic Cardiomyopathy: A Prospective Comparison with Cardiac MR Imaging.

    PubMed

    Lee, Hye-Jeong; Im, Dong Jin; Youn, Jong-Chan; Chang, Suyon; Suh, Young Joo; Hong, Yoo Jin; Kim, Young Jin; Hur, Jin; Choi, Byoung Wook

    2016-07-01

    Purpose To evaluate the feasibility of equilibrium contrast material-enhanced dual-energy cardiac computed tomography (CT) to determine extracellular volume fraction (ECV) in nonischemic cardiomyopathy (CMP) compared with magnetic resonance (MR) imaging. Materials and Methods This study was approved by the institutional review board; informed consent was obtained. Seven healthy subjects and 23 patients (six with hypertrophic CMP, nine with dilated CMP, four with amyloidosis, and four with sarcoidosis) (mean age ± standard deviation, 57.33 years ± 14.82; 19 male participants [63.3%]) were prospectively enrolled. Twelve minutes after contrast material injection (1.8 mL/kg at 3 mL/sec), dual-energy cardiac CT was performed. ECV was measured by two observers independently. Hematocrit levels were compared between healthy subjects and patients with the Mann-Whitney U test. In per-subject analysis, interobserver agreement for CT was assessed with the intraclass correlation coefficient (ICC), and intertest agreement between MR imaging and CT was assessed with Bland-Altman analysis. In per-segment analysis, Student t tests in the linear mixed model were used to compare ECV on CT images between healthy subjects and patients. Results Hematocrit level was 43.44% ± 1.80 for healthy subjects and 41.23% ± 5.61 for patients with MR imaging (P = .16) and 43.50% ± 1.92 for healthy subjects and 41.35% ± 5.92 for patients with CT (P = .15). For observer 1 in per-subject analysis, ECV was 34.18% ± 8.98 for MR imaging and 34.48% ± 8.97 for CT. For observer 2, myocardial ECV was 34.42% ± 9.03 for MR imaging and 33.98% ± 9.05 for CT. Interobserver agreement for ECV at CT was excellent (ICC = 0.987). Bland-Altman analysis between MR imaging and CT showed a small bias (-0.06%), with 95% limits of agreement of -1.19 and 1.79. Compared with healthy subjects, patients with hypertrophic CMP, dilated CMP, amyloidosis, and sarcoidosis had significantly higher myocardial ECV at dual

  15. Comparison of meta-analyses among elastosonography (ES) and positron emission tomography/computed tomography (PET/CT) imaging techniques in the application of prostate cancer diagnosis.

    PubMed

    Ouyang, Qiaohong; Duan, Zhongxiang; Lei, Jixiao; Jiao, Guangli

    2016-03-01

    The early diagnosis of prostate cancer (PCa) appears to be of vital significance for the provision of appropriate treatment programs. Even though several sophisticated imaging techniques such as positron emission tomography/computed tomography (PET/CT) and elastosonography (ES) have already been developed for PCa diagnosis, the diagnostic accuracy of these imaging techniques is still controversial to some extent. Therefore, a comprehensive meta-analysis in this study was performed to compare the accuracy of various diagnostic imaging methods for PCa, including 11C-choline PET/CT, 11C-acetate PET/CT, 18F-fluorocholine PET/CT, 18F-fluoroglucose PET/CT, transrectal real-time elastosonography (TRTE), and shear-wave elastosonography (SWE). The eligible studies were identified through systematical searching for the literature in electronic databases including PubMed, Cochrane, and Web of Science. On the basis of the fixed-effects model, the pooled sensitivity (SEN), specificity (SPE), and area under the receiver operating characteristics curve (AUC) were calculated to estimate the diagnostic accuracy of 11C-choline PET/CT, 11C-acetate PET/CT, 18F-fluorocholine (FCH) PET/CT, 18F-fluoroglucose (FDG) PET/CT, TRTE, and SWE. All the statistical analyses were conducted with R language Software. The present meta-analysis incorporating a total of 82 studies demonstrated that the pooled sensitivity of the six imaging techniques were sorted as follows: SWE > 18F-FCH PET/CT > 11C-choline PET/CT > TRTE > 11C-acetate PET/CT > 18F-FDG PET/CT; the pooled specificity were also compared: SWE > 18F-FCH PET/CT > 11C-choline PET/CT > TRTE > 18F-FDG PET/CT > 11C-acetate PET/CT; finally, the pooled diagnostic accuracy of the six imaging techniques based on AUC were ranked as below: SWE > 18F-FCH PET/CT > 11C-choline PET/CT > TRTE > 11C-acetate PET/CT > 18F-FDG PET/CT. SWE and 18F-FCH PET/CT imaging could offer more assistance in the

  16. System manual for the University of Pennsylvania retrofitted solar heated Philadelphia row home (SolaRow)

    SciTech Connect

    Zinnes, I.; Lior, N.

    1980-05-01

    The University of Pennsylvania SolaRow house, an urban row home retrofitted for comfort and domestic hot water heating, was extensively instrumented for performance monitoring and acquisition of weather and solar radiation data. This report describes the heating and instrumentation systems, provides the details for instrumentation, piping and valve identification, and specifies the operation and maintenance of the heating and data acquisition systems. The following are included: (1) system flow diagrams; (2) valve and cable identification tables; (3) wiring diagrams; and (4) start-up, normal operation, shut-down, maintenance and trouble-shooting procedures. It thus provides the necessary technical information to permit system operation and monitoring, overall system performance analysis and optimization, and acquisition of climatological data.

  17. [CT diagnosis of coal workers' pneumoconiosis].

    PubMed

    Pan, J S

    1989-02-01

    In order to evaluate the usefulness of CT in CWP, 100 coal workers were examined with both chest radiograph and CT scan. Comparison was done, the result indicated that both modalities yielded similar sensitivity to simple CWP. The CT score of simple CWP correlated well with ILO classification and 1986 Chinese criteria for staging of pneumoconiosis, whereas in complicated CWP, the CT scan was significantly superior to chest radiograph. CT scan identified readily large opacities. It could detect large opacities in 40% of simple CWP diagnosed on the basis of chest radiograph. CT scan also identified more cavities and calcifications within large opacities. The CT attenuation values were less reliable. The authors were of the opinion that at present CT attenuation values is not recommended for routine evaluation of CWP. PMID:2758921

  18. SU-E-E-12: Validation of the Implementation of Different CT Scanners in Proton Treatment Planning

    SciTech Connect

    Fuentes, C Llina; Geismer, D; Christiaens, M; Vermeren, X; Ding, X

    2015-06-15

    Purpose: To quantify the impact of the relationship of CT number and Relative Stopping Power (RSP) among different CT-scanners in the evaluation of dose distribution, for different tumor sites and proton therapy modalities like Pencil Beam and Uniform Scanning. Methods: The same tissue characterization phantom was used to analyze the difference in the X-rays energy spectra of 2 CT scanners of the same vendor. One CT is for planning and the other for treatment verification. The Hounsfield unit (HU) variations and associated dosimetric uncertainty were investigated in uniform scanning and pencil beam treatment plans of different sites. At the same time comparisons of the CT calibration curve were done using the same acquisition protocols. The phantom was imaged on a 16 multi-row CT scanner, with energies of 120 and 140 kVp,currents of 263 and 245 mA and slice thickness of 2 and 3mm respectively. The dosimetric uncertainty of the plans was evaluated in a homogeneus phantom comparing DVHs, gamma index criteria 3% 3mm, and range between them. Results: The variation of HU was within the standard deviation of the average for each tissue substitute. The curves fitted with a bilinear interpolation show a maximum deviation in high density materials like cortical bone and solid water, where the HU values deviated more than 0,6% for the 120kVp protocol. For the others curves the deviation was more than 2% for low densities materials. The gamma index uncertainty criteria passed in all the cases. Conclusion: The HU variations for the different scanners were ≤3%. Lower than the 3,5% uncertainties considered in our treatment planning system. The dosimetric analysis shows that the X-ray spectrum has a small effect on the HU-RSP curve, allowing the use of a single tissue characterization curve in our proton treatment planning system for plans verifications.

  19. CT scan

    MedlinePlus

    ... that slides into the center of the CT scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you. Modern spiral scanners can perform the exam without stopping. A computer ...

  20. SU-E-J-141: Comparison of Dose Calculation On Automatically Generated MRBased ED Maps and Corresponding Patient CT for Clinical Prostate EBRT Plans

    SciTech Connect

    Schadewaldt, N; Schulz, H; Helle, M; Renisch, S; Frantzen-Steneker, M; Heide, U

    2014-06-01

    Purpose: To analyze the effect of computing radiation dose on automatically generated MR-based simulated CT images compared to true patient CTs. Methods: Six prostate cancer patients received a regular planning CT for RT planning as well as a conventional 3D fast-field dual-echo scan on a Philips 3.0T Achieva, adding approximately 2 min of scan time to the clinical protocol. Simulated CTs (simCT) where synthesized by assigning known average CT values to the tissue classes air, water, fat, cortical and cancellous bone. For this, Dixon reconstruction of the nearly out-of-phase (echo 1) and in-phase images (echo 2) allowed for water and fat classification. Model based bone segmentation was performed on a combination of the DIXON images. A subsequent automatic threshold divides into cortical and cancellous bone. For validation, the simCT was registered to the true CT and clinical treatment plans were re-computed on the simCT in pinnacle{sup 3}. To differentiate effects related to the 5 tissue classes and changes in the patient anatomy not compensated by rigid registration, we also calculate the dose on a stratified CT, where HU values are sorted in to the same 5 tissue classes as the simCT. Results: Dose and volume parameters on PTV and risk organs as used for the clinical approval were compared. All deviations are below 1.1%, except the anal sphincter mean dose, which is at most 2.2%, but well below clinical acceptance threshold. Average deviations are below 0.4% for PTV and risk organs and 1.3% for the anal sphincter. The deviations of the stratifiedCT are in the same range as for the simCT. All plans would have passed clinical acceptance thresholds on the simulated CT images. Conclusion: This study demonstrated the clinical usability of MR based dose calculation with the presented Dixon acquisition and subsequent fully automatic image processing. N. Schadewaldt, H. Schulz, M. Helle and S. Renisch are employed by Phlips Technologie Innovative Techonologies, a

  1. Comparison of CE-FDG-PET/CT with CE-FDG-PET/MR in the evaluation of osseous metastases in breast cancer patients

    PubMed Central

    Catalano, O A; Nicolai, E; Rosen, B R; Luongo, A; Catalano, M; Iannace, C; Guimaraes, A; Vangel, M G; Mahmood, U; Soricelli, A; Salvatore, M

    2015-01-01

    Background: Despite improvements in treatments, metastatic breast cancer remains difficult to cure. Bones constitute the most common site of first-time recurrence, occurring in 40–75% of cases. Therefore, evaluation for possible osseous metastases is crucial. Technetium 99 (99Tc) bone scintigraphy and fluorodexossyglucose (FDG) positron emission tomography (PET)-computed tomography (PET-CT) are the most commonly used techniques to assess osseous metastasis. PET magnetic resonance (PET-MR) imaging is an innovative technique still under investigation. We compared the capability of PET-MR to that of same-day PET-CT to assess osseous metastases in patients with breast cancer. Methods: One hundred and nine patients with breast cancer, who underwent same-day contrast enhanced (CE)-PET-CT and CE-PET-MR, were evaluated. CE-PET-CT and CE-PET-MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Binomial confidence intervals and a χ2 test were used for categorical data, and paired t-test was used for the SUVmax data; a non-informative prior Bayesian approach was used to estimate and compare the specificities. Results: Osseous metastases affected 25 out 109 patients. Metastases were demonstrated by CE-PET-CT in 22 out of 25 patients (88%±7%), and by CE-PET-MR in 25 out of 25 patients (100%). CE-PET-CT revealed 90 osseous metastases and CE-PET-MR revealed 141 osseous metastases (P<0.001). The estimated sensitivity of CE-PET-CT and CE-PET-MR were 0.8519 and 0.9630, respectively. The estimated specificity for CE-FDG-PET-MR was 0.9884. The specificity of CE-PET-CT cannot be determined from patient-level data, because CE-PET-CT yielded a false-positive lesion in a patient who also had other, true metastases. Conclusions: CE-PET-MR detected a higher number of osseous metastases than did same-day CE-PET-CT, and was positive for 12% of the patients

  2. Airway Segmentation and Centerline Extraction from Thoracic CTComparison of a New Method to State of the Art Commercialized Methods

    PubMed Central

    Reynisson, Pall Jens; Scali, Marta; Smistad, Erik; Hofstad, Erlend Fagertun; Leira, Håkon Olav; Lindseth, Frank; Nagelhus Hernes, Toril Anita; Amundsen, Tore; Sorger, Hanne; Langø, Thomas

    2015-01-01

    airways and the centerlines. Reference segmentation comparison averages and standard deviations for MPM and TSF correspond to literature. Conclusion The TSF is able to segment the airways and extract the centerlines in one single step. The number of branches found is lower for the TSF method than in Mimics. OsiriX demands the highest number of clicks to process the data, the segmentation is often sparse and extracting the centerline requires the use of another software system. Two of the software systems performed satisfactory with respect to be used in preprocessing CT images for navigated bronchoscopy, i.e. the TSF method and the MPM. According to reference segmentation both TSF and MPM are comparable with other segmentation methods. The level of automaticity and the resulting high number of branches plus the fact that both centerline and the surface of the airways were extracted, are requirements we considered particularly important. The in house method has the advantage of being an integrated part of a navigation platform for bronchoscopy, whilst the other methods can be considered preprocessing tools to a navigation system. PMID:26657513

  3. TU-A-12A-02: Novel Lung Ventilation Imaging with Single Energy CT After Single Inhalation of Xenon: Comparison with SPECT Ventilation Images

    SciTech Connect

    Negahdar, M; Yamamoto, T; Shultz, D; Gable, L; Shan, X; Mittra, E; Loo, B; Maxim, P; Diehn, M

    2014-06-15

    Purpose: We propose a novel lung functional imaging method to determine the spatial distribution of xenon (Xe) gas in a single inhalation as a measure of regional ventilation. We compare Xe-CT ventilation to single-photon emission CT (SPECT) ventilation, which is the current clinical reference. Regional lung ventilation information may be useful for the diagnosis and monitoring of pulmonary diseases such as COPD, radiotherapy planning, and assessing the progression of toxicity after radiation therapy. Methods: In an IRB-approved clinical study, Xe-CT and SPECT ventilation scans were acquired for three patients including one patient with severe emphysema and two lung cancer patients treated with radiotherapy. For Xe- CT, we acquired two breath-hold single energy CT images of the entire lung with inspiration of 100% O2 and a mixture of 70% Xe and 30% O2, respectively. A video biofeedback system was used to achieve reproducible breath-holds. We used deformable image registration to align the breathhold images with each other to accurately subtract them, producing a map of the distribution of Xe as a surrogate of lung ventilation. We divided each lung into twelve parts and correlated the Hounsfield unit (HU) enhancement at each part with the SPECT ventilation count of the corresponding part of the lung. Results: The mean of the Pearson linear correlation coefficient values between the Xe-CT and ventilation SPECT count for all three patients were 0.62 (p<0.01). The Xe-CT image had a higher resolution than SPECT, and did not show central airway deposition artifacts that were present in the SPECT image. Conclusion: We developed a rapid, safe, clinically practical, and potentially widely accessible method for regional lung functional imaging. We demonstrated strong correlations between the Xe-CT ventilation image and SPECT ventilation image as the clinical reference. This ongoing study will investigate more patients to confirm this finding.

  4. Biomechanical determinants of elite rowing technique and performance.

    PubMed

    Buckeridge, E M; Bull, A M J; McGregor, A H

    2015-04-01

    In rowing, the parameters of injury, performance, and technique are all interrelated and in dynamic equilibrium. Whilst rowing requires extreme physical strength and endurance, a high level of skill and technique is essential to enable an effective transfer of power through the rowing sequence. This study aimed to determine discrete aspects of rowing technique, which strongly influence foot force production and asymmetries at the foot-stretchers, as these are biomechanical parameters often associated with performance and injury risk. Twenty elite female rowers performed an incremental rowing test on an instrumented rowing ergometer, which measured force at the handle and foot-stretchers, while three-dimensional kinematic recordings of the ankle, knee, hip, and lumbar-pelvic joints were made. Multiple regression analyses identified hip kinematics as a key predictor of foot force output (R(2)  = 0.48), whereas knee and lumbar-pelvic kinematics were the main determinants in optimizing the horizontal foot force component (R(2)  = .41). Bilateral asymmetries of the foot-stretchers were also seen to significantly influence lumbar-pelvic kinematics (R(2)  = 0.43) and pelvic twisting (R(2)  = 0.32) during the rowing stroke. These results provide biomechanical evidence toward aspects of technique that can be modified to optimize force output and performance, which can be of direct benefit to coaches and athletes. PMID:25039605

  5. Rectal cancer staging: Multidetector-row computed tomography diagnostic accuracy in assessment of mesorectal fascia invasion

    PubMed Central

    Ippolito, Davide; Drago, Silvia Girolama; Franzesi, Cammillo Talei; Fior, Davide; Sironi, Sandro

    2016-01-01

    AIM: To assess the diagnostic accuracy of multidetector-row computed tomography (MDCT) as compared with conventional magnetic resonance imaging (MRI), in identifying mesorectal fascia (MRF) invasion in rectal cancer patients. METHODS: Ninety-one patients with biopsy proven rectal adenocarcinoma referred for thoracic and abdominal CT staging were enrolled in this study. The contrast-enhanced MDCT scans were performed on a 256 row scanner (ICT, Philips) with the following acquisition parameters: tube voltage 120 KV, tube current 150-300 mAs. Imaging data were reviewed as axial and as multiplanar reconstructions (MPRs) images along the rectal tumor axis. MRI study, performed on 1.5 T with dedicated phased array multicoil, included multiplanar T2 and axial T1 sequences and diffusion weighted images (DWI). Axial and MPR CT images independently were compared to MRI and MRF involvement was determined. Diagnostic accuracy of both modalities was compared and statistically analyzed. RESULTS: According to MRI, the MRF was involved in 51 patients and not involved in 40 patients. DWI allowed to recognize the tumor as a focal mass with high signal intensity on high b-value images, compared with the signal of the normal adjacent rectal wall or with the lower tissue signal intensity background. The number of patients correctly staged by the native axial CT images was 71 out of 91 (41 with involved MRF; 30 with not involved MRF), while by using the MPR 80 patients were correctly staged (45 with involved MRF; 35 with not involved MRF). Local tumor staging suggested by MDCT agreed with those of MRI, obtaining for CT axial images sensitivity and specificity of 80.4% and 75%, positive predictive value (PPV) 80.4%, negative predictive value (NPV) 75% and accuracy 78%; while performing MPR the sensitivity and specificity increased to 88% and 87.5%, PPV was 90%, NPV 85.36% and accuracy 88%. MPR images showed higher diagnostic accuracy, in terms of MRF involvement, than native axial images

  6. Maximal strength on different resistance training rowing exercises predicts start phase performance in elite kayakers.

    PubMed

    Ualí, Ismael; Herrero, Azael J; Garatachea, Nuria; Marín, Pedro J; Alvear-Ordenes, Ildefonso; García-López, David

    2012-04-01

    This study aimed to examine the relationship existing between maximum strength values in 2 common resistance training row exercises (bilateral bench pull [BBP] and one-arm cable row [OACR]) and short sprint performance in elite kayakers. Ten junior kayakers (5 women and 5 men) were tested on different days for 1 repetition maximum (1RM) and maximal voluntary isometric contraction in both exercises. Moreover, a 12-m sprint kayak was performed in a dew pond to record split times (2, 5, and 10 m), peak velocity, distance completed considering the first 8 strokes, and mean acceleration induced by right blade and left blade strokes. No differences (p > 0.05) were observed when right and left arms were compared in sprint testing or strength testing variables. Maximal strength values in BBP and OACR were significantly correlated with short sprint performance variables, showing the bilateral exercise with slightly stronger correlation coefficients than the unilateral seated row. Moreover, the relationship between strength testing and sprint testing variables is stronger when maximal force is measured through a dynamic approach (1RM) in comparison with an isometric approach. In conclusion, maximal strength in BBP and OACR is a good predictor of the start phase performance in elite sprint kayakers, mainly the 1RM value in BBP. PMID:22446667

  7. A Spreadsheet for the Mixing of a Row of Jets with a Confined Crossflow. Supplement

    NASA Technical Reports Server (NTRS)

    Holderman, J. D.; Smith, T. D.; Clisset, J. R.; Lear, W. E.

    2005-01-01

    An interactive computer code, written with a readily available software program, Microsoft Excel (Microsoft Corporation, Redmond, WA) is presented which displays 3 D oblique plots of a conserved scalar distribution downstream of jets mixing with a confined crossflow, for a single row, double rows, or opposed rows of jets with or without flow area convergence and/or a non-uniform crossflow scalar distribution. This project used a previously developed empirical model of jets mixing in a confined crossflow to create an Microsoft Excel spreadsheet that can output the profiles of a conserved scalar for jets injected into a confined crossflow given several input variables. The program uses multiple spreadsheets in a single Microsoft Excel notebook to carry out the modeling. The first sheet contains the main program, controls for the type of problem to be solved, and convergence criteria. The first sheet also provides for input of the specific geometry and flow conditions. The second sheet presents the results calculated with this routine to show the effects on the mixing of varying flow and geometric parameters. Comparisons are also made between results from the version of the empirical correlations implemented in the spreadsheet and the versions originally written in Applesoft BASIC (Apple Computer, Cupertino, CA) in the 1980's.

  8. A Spreadsheet for the Mixing of a Row of Jets with a Confined Crossflow

    NASA Technical Reports Server (NTRS)

    Holderman, J. D.; Smith, T. D.; Clisset, J. R.; Lear, W. E.

    2005-01-01

    An interactive computer code, written with a readily available software program, Microsoft Excel (Microsoft Corporation, Redmond, WA) is presented which displays 3 D oblique plots of a conserved scalar distribution downstream of jets mixing with a confined crossflow, for a single row, double rows, or opposed rows of jets with or without flow area convergence and/or a non-uniform crossflow scalar distribution. This project used a previously developed empirical model of jets mixing in a confined crossflow to create an Microsoft Excel spreadsheet that can output the profiles of a conserved scalar for jets injected into a confined crossflow given several input variables. The program uses multiple spreadsheets in a single Microsoft Excel notebook to carry out the modeling. The first sheet contains the main program, controls for the type of problem to be solved, and convergence criteria. The first sheet also provides for input of the specific geometry and flow conditions. The second sheet presents the results calculated with this routine to show the effects on the mixing of varying flow and geometric parameters. Comparisons are also made between results from the version of the empirical correlations implemented in the spreadsheet and the versions originally written in Applesoft BASIC (Apple Computer, Cupertino, CA) in the 1980's.

  9. Comparison of diagnostic performance of CT and MRI for abdominal staging of pediatric renal tumors: a report from the Children's Oncology Group

    PubMed Central

    Servaes, Sabah; Naranjo, Arlene; Geller, James I.; Ehrlich, Peter F.; Gow, Kenneth W.; Perlman, Elizabeth J.; Dome, Jeffrey S.; Gratias, Eric; Mullen, Elizabeth A.

    2015-01-01

    Background CT and MRI are both used for abdominal staging of pediatric renal tumors. The diagnostic performance of the two modalities for local and regional staging of renal tumors has not been systematically evaluated. Objective To compare the diagnostic performance of CT and MRI for local staging of pediatric renal tumors. Materials and methods The study population was derived from the AREN03B2 study of the Children's Oncology Group. Baseline abdominal imaging performed with both CT and MRI within 30 days of nephrectomy was available for retrospective review in 82 renal tumor cases. Each case was evaluated for capsular penetration, lymph node metastasis, tumor thrombus, preoperative tumor rupture, and synchronous contralateral lesions. The surgical and pathological findings at central review were the reference standard. Results The sensitivity of CT and MRI for detecting capsular penetration was 68.6% and 62.9%, respectively (P=0.73), while specificity was 86.5% and 83.8% (P=1.0). The sensitivity of CT and MRI for detecting lymph node metastasis was 76.5% and 52.9% (P=0.22), and specificity was 90.4% and 92.3% (P=1.0). Synchronous contralateral lesions were identified by CT in 4/9 cases and by MRI in 7/9 cases. Conclusion CT and MRI have similar diagnostic performance for detection of lymph node metastasis and capsular penetration. MR detected more contralateral synchronous lesions; however these were present in a very small number of cases. Either modality can be used for initial loco–regional staging of pediatric renal tumors. PMID:25135711

  10. Comparison of non-sedated brain MRI and CT for the detection of acute traumatic injury in children 6 years of age or less.

    PubMed

    Young, Joseph Yeen; Duhaime, Ann-Christine; Caruso, Paul Albert; Rincon, Sandra Patricia

    2016-08-01

    CT is considered the first-line study for acute intracranial injury in children because of its availability, detection of acute hemorrhage, and lack of sedation. An MRI study with rapidly acquired sequences can obviate the need for sedation and radiation. We compared the detection rate of rapid non-sedated brain MRI to CT for traumatic head injury in young children. We reviewed a series of children 6 years of age or less who presented to our ED during a 5-year period with head trauma and received a non-sedated brain MRI and CT within 24 h of injury. Most MRI studies were limited to triplane T2 and susceptibility sequences. Two neuroradiologists reviewed the MRIs and CTs and assessed the following findings: fracture, epidural hematoma (EDH)/subdural hematoma (SDH), subarachnoid hemorrhage (SAH), intraventricular hemorrhage (IVH), and parenchymal injury. Thirty of 33 patients had radiologically identified traumatic injuries. There was an overall agreement of 82 % between the two modalities. Skull fracture was the only injury subtype which had a statistically significant difference in detection between CT and MRI (p = 0.0001), with MRI missing 14 of 21 fractures detected on CT. While not statistically significant, MRI had a higher detection rate of EDH/SDH (p = 0.34), SAH (p = 0.07), and parenchymal injuries (p = 0.50). Non-sedated MRI has similar detection rates to CT for intracranial injury in young children presenting with acute head trauma and may be an alternative to CT in select patients. PMID:27166965

  11. Fuel metabolism during severe rowing exercise

    SciTech Connect

    Hoyt, R.W.; Lubowitz, J.; Asakura, T.; Stein, T.P.

    1986-03-01

    Eight elite oarsmen were studied during and after six min of severe ergometer exercise. Power output averaged 380 +/- 28 watts. Serial venous blood samples and gas exchange measurements were obtained during exercise. In 4 of the 8 subjects, a primed periodic oral dose of the tracer (6,6-/sup 2/H/sub 2/)glucose was used to determine the effects of severe exercise on glucose metabolism. During exercise, the levels of lactate progressively increased to 12.2 +/- 1.3 mM (SE). There was little change in isotopic glucose enrichment during exercise (from 2.95 +/- 0.30 to 2.55 +/- 0.23 atom percent excess, APE). During recovery, isotopic glucose enrichment decreased significantly to 1.40 +/- 0.14 APE, indicating a substantial post-exercise plasma glucose flux. There were significant post-exercise increases in plasma glucose accumulation (from 84 +/- 5 to 131 +/- 3 mg/dl) and insulin concentration (0.57 +/- 0.08 to 1.34 +/- 0.15 ng/ml). These results suggest that muscle glycogen is the primary source of fuel during six minutes of maximal rowing exercise.

  12. 1. View of background of row of Double Creole Quarters ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View of background of row of Double Creole Quarters looking S across mill pond. - Laurel Valley Sugar Plantation, Double Creole Quarters, 2 Miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  13. 10. Photocopy of c. 1906 photograph looking SE at row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Photocopy of c. 1906 photograph looking SE at row of double Creole quarters along Main Street. - Laurel Valley Sugar Plantation, Double Creole Quarters, 2 Miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  14. 9. Photocopy of c. 1906 photograph looking SE at row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Photocopy of c. 1906 photograph looking SE at row of double Creole workers' houses along Main Street. - Laurel Valley Sugar Plantation, Double Creole Quarters, 2 Miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  15. View of northern portion of Mueller property, looking south. Row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of northern portion of Mueller property, looking south. Row of magnolia trees along western property boundary on East Avenue. - Ernst Mueller House, 6563 East Avenue, Rancho Cucamonga, San Bernardino County, CA

  16. 26. INTERIOR VIEW SHOWING ROW OF TIMBER SUPPORT TOWERS BUILT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. INTERIOR VIEW SHOWING ROW OF TIMBER SUPPORT TOWERS BUILT AS TEMPORARY TRUSS REINFORCEMENT (NOTE STEEL STRUCTURES ATOP TIMBER BRACING) - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  17. Detail, starpattern balustrade of north span, from northwest, showing row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail, star-pattern balustrade of north span, from northwest, showing row of four star-pattern railing slabs bracketed by simple molded concrete balusters - Horner Street Bridge, Horner Street over Stonycreek River, Johnstown, Cambria County, PA

  18. 1. View looking southeast down senior officer row. Building 6 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View looking southeast down senior officer row. Building 6 on left and senior officer housing on right. Galaxy Street in foreground. - Chanute Air Force Base, East of Route 45 & south of Rantoul, Rantoul, Champaign County, IL

  19. Detail view of stylized panel on end of seating row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of stylized panel on end of seating row - National Home for Disabled Volunteer Soldiers, Pacific Branch, Wadsworth Theater, 11301 Wilshire Boulevard, West Los Angeles, Los Angeles County, CA

  20. View of northwest portion of Mueller property, looking southeast. Row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of northwest portion of Mueller property, looking southeast. Row of magnolia trees along western boundary on east avenue. - Ernst Mueller House, 6563 East Avenue, Rancho Cucamonga, San Bernardino County, CA

  1. THERMALWATER FLOW METER. Hot Springs National Park, Bathhouse Row, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    THERMAL-WATER FLOW METER. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  2. General view of building in context showing row of residences ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of building in context showing row of residences adjacent to golf course, facing northeast. - Marine Barracks, Panama Canal, Officers' Quarters, 800' West of Bruja Road, Balboa, Former Panama Canal Zone, CZ

  3. Cell block eleven, looking from the "Death Row" exercise yard, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cell block eleven, looking from the "Death Row" exercise yard, facing north (note cell block fifteen to the right and cell block fourteen in the distance_ - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

  4. Row effect for R-11 condensation on enhanced tubes

    SciTech Connect

    Webb, R.L.; Murawski, C.G. )

    1990-08-01

    Experimental results of a condensation row effect study on enhanced tubes are presented. A test cell was constructed to condense Refrigerant-11 on the shell side of a vertical bank of five horizontal tubes. Four distinctly different commercially available tubes were tested. The tubes are a 1024-fpm integral fin, the Wolverine Tube-C, Wieland GEWA-SC, and the Tred-D. A modified Turbo-C tube was also tested. Experimental and visual observations are used to understand the row effect due to condensate loading. By plotting the data in the form of the local condensation coefficient versus condensate Reynolds number, the results may be interpreted for any number of tube rows, up to the maximum Reynolds numbers tested. Bundle average condensation coefficients may be established by integrating the h versus Re values over the number of tube rows.

  5. Principles of CT and CT technology.

    PubMed

    Goldman, Lee W

    2007-09-01

    This article provides a review of the basic principles of CT within the context of the evolution of CT. Modern CT technology can be understood as a natural progression of improvements and innovations in response to both engineering problems and clinical requirements. Detailed discussions of multislice CT, CT image quality evaluation, and radiation doses in CT will be presented in upcoming articles in this series. PMID:17823453

  6. Lumbosacral spine CT

    MedlinePlus

    Spinal CT; CT - lumbosacral spine ... In other cases, a CT of the lumbosacral spine may be done after injecting contrast dye into ... of the body. A CT of the lumbosacral spine can evaluate fractures and changes of the spine, ...

  7. Thoracic CT

    MedlinePlus

    ... table that slides into the center of the scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you. ... than 300 pounds, have your doctor contact the scanner operator before the exam. CT scanners have a ...

  8. Evaluation of lymph node status after neoadjuvant chemotherapy in breast cancer patients: comparison of diagnostic performance of ultrasound, MRI and 18F-FDG PET/CT

    PubMed Central

    You, S; Kang, D K; Jung, Y S; An, Y-S; Jeon, G S

    2015-01-01

    Objective: To evaluate the diagnostic performance of ultrasound, MRI and fluorine-18 fludeoxyglucose positron emission tomography (18F-FDG PET)/CT for the diagnosis of metastatic axillary lymph node (ALN) after neoadjuvant chemotherapy (NAC) and to find out histopathological factors affecting the diagnostic performance of these imaging modalities. Methods: From January 2012 to November 2014, 191 consecutive patients with breast cancer who underwent NAC before surgery were retrospectively reviewed. We included 139 patients with ALN metastasis that was confirmed on fine needle aspiration or core needle biopsy at initial diagnosis. Results: After NAC, 39 (28%) patients showed negative conversion of ALN on surgical specimens of sentinel lymph node (LN) or ALN. The sensitivity of ultrasound, MRI and PET/CT was 50% (48/96), 72% (70/97) and 22% (16/73), respectively. The specificity of ultrasound, MRI and PET/CT was 77% (30/39), 54% (21/39) and 85% (22/26), respectively. The Az value of combination of ultrasound and PET/CT was the highest (0.634) followed by ultrasound (0.626) and combination of ultrasound, MRI and PET/CT (0.617). The size of tumour deposit in LN and oestrogen receptor was significantly associated with the diagnostic performance of ultrasound (p < 0.001 and p = 0.009, respectively) and MRI (p = 0.045 and p = 0.036, respectively). The percentage diameter decrease, size of tumour deposit in LN, progesterone receptor, HER2 and histological grade were significantly associated with the diagnostic performance of PET/CT (p = 0.023, p = 0.002, p = 0.036, p = 0.044 and p = 0.008, respectively). On multivariate logistic regression analysis, size of tumour deposit within LN was identified as being independently associated with diagnostic performance of ultrasound [odds ratio, 13.07; 95% confidence interval (CI), 2.95–57.96] and PET/CT (odds ratio, 6.47; 95% CI, 1.407–29.737). Conclusion: Combination of three imaging modalities

  9. Molecular Imaging of Chemokine Receptor CXCR4 in Non-Small Cell Lung Cancer Using 68Ga-Pentixafor PET/CT: Comparison With 18F-FDG.

    PubMed

    Derlin, Thorsten; Jonigk, Danny; Bauersachs, Johann; Bengel, Frank M

    2016-04-01

    We report the case of a 62-year-old woman with a history of ST-elevation myocardial infarction who underwent 68Ga-Pentixafor PET/CT for characterization of postinfarct myocardial inflammation. 68Ga-Pentixafor PET/CT incidentally demonstrated marked CXCR4 expression in a space-occupying lesion in the right upper lobe. Corresponding 18F-FDG PET/CT showed increased metabolism, and subsequent biopsy revealed non-small cell lung cancer. Immunohistochemistry confirmed that CXCR4 was highly expressed on tumor cells. 68Ga-Pentixafor is a novel CXCR4-targeted probe for PET imaging of CXCR4-positive tumors and holds promise for tumor staging and prognostic stratification. CXCR4-targeted radionuclide therapy represents a therapy option in metastasized diseases. PMID:26756098

  10. Soft tissue imaging with photon counting spectroscopic CT

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.

    2015-03-01

    The purpose of this work was experimental investigation of photon counting spectroscopic CT (PCS-CT) imaging of anatomical soft tissue with clinically relevant size. The imaging experiments were performed using a spectroscopic CT system based on CdZnTe photon counting detector with two rows of pixels, 256 pixels in each row, 1  ×  1 mm2 pixel size, and 25.6 cm detector length. The detector could split the x-ray energy spectrum to 5 regions (energy bins), and acquire 5 multi-energy (spectroscopic) CT images in a single CT scan. A sample of round shaped anatomical soft tissue of 14 cm diameter including lean and fat was used for imaging. To avoid the negative effect of anatomical noise on quantitative analysis, a spectroscopic CT phantom with tissue equivalent solid materials was used. The images were acquired at 60, 90, and 120 kVp tube voltages, and spectroscopic image series were acquired with 3 and 5 energy bins. Spectroscopic CT numbers were introduced and used to evaluate an energy selective image series. The anatomical soft tissue with 14 cm diameter was visualized with good quality and without substantial artifacts by the photon counting spectroscopic CT system. The effects of the energy bin crosstalk on spectroscopic CT numbers were quantified and analyzed. The single and double slice PCS-CT images were acquired and compared. Several new findings were observed, including the effect of soft tissue non-uniformity on image artifacts, unique status of highest energy bin, and material dependent visualization in spectroscopic image series. Fat-lean decomposition was performed using dual energy subtraction and threshold segmentation methods, and compared. Using K-edge filtered x-rays improved fat-lean decomposition as compared to conventional x-rays. Several new and important aspects of the PCS-CT were investigated. These include imaging soft tissue with clinically relevant size, single- and double-slice PCS-CT imaging, using spectroscopic CT

  11. Soft tissue imaging with photon counting spectroscopic CT.

    PubMed

    Shikhaliev, Polad M

    2015-03-21

    The purpose of this work was experimental investigation of photon counting spectroscopic CT (PCS-CT) imaging of anatomical soft tissue with clinically relevant size. The imaging experiments were performed using a spectroscopic CT system based on CdZnTe photon counting detector with two rows of pixels, 256 pixels in each row, 1  ×  1 mm(2) pixel size, and 25.6 cm detector length. The detector could split the x-ray energy spectrum to 5 regions (energy bins), and acquire 5 multi-energy (spectroscopic) CT images in a single CT scan. A sample of round shaped anatomical soft tissue of 14 cm diameter including lean and fat was used for imaging. To avoid the negative effect of anatomical noise on quantitative analysis, a spectroscopic CT phantom with tissue equivalent solid materials was used. The images were acquired at 60, 90, and 120 kVp tube voltages, and spectroscopic image series were acquired with 3 and 5 energy bins. Spectroscopic CT numbers were introduced and used to evaluate an energy selective image series. The anatomical soft tissue with 14 cm diameter was visualized with good quality and without substantial artifacts by the photon counting spectroscopic CT system. The effects of the energy bin crosstalk on spectroscopic CT numbers were quantified and analyzed. The single and double slice PCS-CT images were acquired and compared. Several new findings were observed, including the effect of soft tissue non-uniformity on image artifacts, unique status of highest energy bin, and material dependent visualization in spectroscopic image series. Fat-lean decomposition was performed using dual energy subtraction and threshold segmentation methods, and compared. Using K-edge filtered x-rays improved fat-lean decomposition as compared to conventional x-rays. Several new and important aspects of the PCS-CT were investigated. These include imaging soft tissue with clinically relevant size, single- and double-slice PCS-CT imaging, using spectroscopic CT

  12. Unsteady Blade Row Interaction in a Transonic Turbine

    NASA Technical Reports Server (NTRS)

    Dorney, Daniel J.

    1996-01-01

    Experimental data from jet-engine tests have indicated that unsteady blade row interaction effects can have a significant impact on the performance of multiple-stage turbines. The magnitude of blade row interaction is a function of both blade-count ratio and axial spacing. In the current research program, numerical simulations have been used to quantify the effects of blade count ratio on the performance of an advanced turbine geometries.

  13. Transepicondylar axis accuracy in computer assisted knee surgery: a comparison of the CT-based measured axis versus the CAS-determined axis.

    PubMed

    van der Linden-van der Zwaag, Henrica M J; Valstar, Edward R; van der Molen, Aart J; Nelissen, Rob G H H

    2008-07-01

    Rotational malalignment is recognized as one of the major reasons for knee pain after total knee arthroplasty (TKA). Although Computer Assisted Orthopaedic Surgery (CAOS) systems have been developed to enable more accurate and consistent alignment of implants, it is still unknown whether they significantly improve the accuracy of femoral rotational alignment as compared to conventional techniques. We evaluated the accuracy of the intraoperatively determined transepicondylar axis (TEA) with that obtained from postoperative CT-based measurement in 20 navigated TKA procedures. The intraoperatively determined axis was marked with tantalum (RSA) markers. Two observers measured the posterior condylar angle (PCA) on postoperative CT scans. The PCA measured using the intraoperatively determined axis showed an inter-observer correlation of 0.93. The intra-observer correlation, 0.96, was slightly better than when using the CT-based angle. The PCA had a range of -6 degrees (internal rotation) to 8 degrees (external rotation) with a mean of 3.6 degrees for observer 1 (SD = 4.02 degrees ) and 2.8 degrees for observer 2 (SD = 3.42 degrees ). The maximum difference between the two observers was 4 degrees . All knees had a patellar component inserted with good patellar tracking and no anterior knee pain. The mean postoperative flexion was 113 degrees (SD = 12.9 degrees ). The mean difference between the two epicondylar line angles was 3.1 degrees (SD = 5.37 degrees ), with the CT-based PCA being larger. During CT-free navigation in TKA, a systematic error of 3 degrees arose when determining the TEA. It is emphasized that the intraoperative epicondylar axis is different from the actual CT-based epicondylar axis. PMID:18622794

  14. Comparison Between 99mTc-Sulesomab and 18F-FDG PET/CT in a Patient With Suspected Prosthetic Joint Infection.

    PubMed

    Albano, Domenico; Bosio, Giovanni; Paghera, Barbara; Bertagna, Francesco

    2016-06-01

    Diagnosing prosthetic joint infection is difficult; clinical signs and symptoms, laboratory tests, radiography, and joint aspiration are less sensitive and specific. We report a patient with fever and painful bilateral hip prosthesis, who underwent Tc-sulesomab scan showing moderate tracer uptake at the lateral surface of the right thigh and no signs of prosthesis infection. The F-FDG-PET/CT showed high uptake at the soft tissue of the right hip prosthesis and detected a fistula. Moreover PET/CT discovered an initial bone marrow involvement at the right femur. The subsequent fistulography confirmed the fistula, and the patient underwent definitive fistulotomy successfully. PMID:27055130

  15. Multi-Detector Row Computed Tomography Findings of Pelvic Congestion Syndrome Caused by Dilated Ovarian Veins

    PubMed Central

    Eren, Suat

    2010-01-01

    Objective: To evaluate the efficacy of multi-detector row CT (MDCT) on pelvic congestion syndrome (PCS), which is often overlooked or poorly visualized with routine imaging examination. Materials and Methods: We evaluated the MDCT features of 40 patients with PCS (mean age, 45 years; range, 29–60 years) using axial, coronal, sagittal, 3D volume-rendered, and Maximum Intensity Projection MIP images. Results: MDCT revealed pelvic varices and ovarian vein dilatations in all patients. Bilateral ovarian vein dilatation was present in 25 patients, and 15 patients had unilateral dilatation. While 12 cases of secondary pelvic varices occurred simultaneously with a retroaortic left renal vein, 10 cases were due solely to a mass obstruction or stenosis of venous structures. Conclusion: MDCT is an effective tool in the evaluation of PCS, and it has more advantages than other imaging modalities. PMID:25610142

  16. 77 FR 74237 - T. Rowe Price Associates, Inc., et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ... COMMISSION T. Rowe Price Associates, Inc., et al.; Notice of Application December 7, 2012. AGENCY: Securities... for an exemption from sections 12(d)(1)(A) and (B) of the Act. Applicants: T. Rowe Price Associates, Inc. (``TRP''), T. Rowe Price Institutional Income Funds, Inc. (the ``Corporation'') and T. Rowe...

  17. Dad Vail Regatta, 52 on the Schuylkill, Is the World's Biggest College Rowing Event.

    ERIC Educational Resources Information Center

    Farrell, Charles S.

    1986-01-01

    The Dad Vail Regatta, the world's largest intercollegiate rowing regatta, attracted teams from 73 colleges in 1986 in a broad-based competition, requiring women to row the same race that men row. It is evidence of a growing interest in rowing as an intercollegiate sport. (MSE)

  18. Lactose malabsorption testing in daily clinical practice: a critical retrospective analysis and comparison of the hydrogen/methane breath test and genetic test (c/t-13910 polymorphism) results.

    PubMed

    Enko, Dietmar; Rezanka, Erwin; Stolba, Robert; Halwachs-Baumann, Gabriele

    2014-01-01

    The aim of this study was to establish a retrospective evaluation and comparison of the hydrogen/methane (H2/CH4) breath test and genetic test (C/T-13910 polymorphism) results in lactose malabsorption testing. In total 263 consecutive patients with suspected lactose malabsorption were included in this study. They underwent the H2/CH4 breath test following the ingestion of 50 g lactose and were tested for the C/T-13910 polymorphism. In total 51 patients (19.4%) had a C/C-13910 genotype, indicating primary lactose malabsorption. Only 19 patients (7.2%) also had a positive H2/CH4 breath test. All in all 136 patients (51.69%) had a C/T-13910 and 76 patients (28.91%) a T/T-13910 genotype, indicating lactase persistence. Four patients (1.5%) with the C/T-13910 genotype and one patient (0.4%) with the T/T-13910 genotype had a positive H2/CH4 breath test result, indicating secondary lactose malabsorption. Cohen's Kappa measuring agreement between the two methods was 0.44. Twenty patients (7.6%) with a positive H2/CH4 peak within 60 minutes after lactose ingestion were classified as patients with lactose-dependent small intestinal bacterial overgrowth (SIBO). In conclusion, only moderate agreement between the breath test and the genetic test was shown. Secondary lactose malabsorption as well as preanalytical limitations of the combined H2/CH4 breath test procedure can cause discrepant results. This trial is registered with K-42-13. PMID:24829570

  19. Comparison of SPECT/CT and planar MIBI in terms of operating time and cost in the surgical management of primary hyperparathyroidism.

    PubMed

    Setabutr, Dhave; Vakharia, Kavita; Nogan, Stephen J; Kamel, George N; Allen, Thomas; Saunders, Brian D; Goldenberg, David

    2015-01-01

    We conducted a retrospective study to compare operating times and costs in patients who underwent guided parathyroidectomies with either (1) technetium-99m ((99m)Tc) multiplex ion-beam imaging (MIBI) parathyroid scintigraphy with single-photon emission computed tomography/computed tomography (SPECT/CT) fusion images or (2) sestamibi dual-phase (99m)Tc MIBI planar parathyroid scintigraphy alone preoperatively. Our study population was made up of the first 24 patients at our facility who had undergone SPECT/CT parathyroid imaging with technetium-99m ((99m)Tc) MIBI and a group of 24 patients who had undergone MIBI planar imaging alone. Patient demographics, preoperative laboratory test results, operating times, and hospital charges were analyzed. We found that less operating time was required for the planar MIBI group than in the SPECT/CT group (mean: 135 vs. 158 min), although the difference was not statistically significant. Likewise, the total cost of treatment was lower in the planar MIBI group (mean: $10,035 vs. $11,592); the difference was statistically significant by one measure (p × 0.02, Wilcoxon rank sum test) but not by another (p × 0.06, Student t test). Although SPECT/CT is efficient for patients with small and difficult-to-localize adenomas, it has yet to demonstrate greater efficacy or cost-effectiveness than planar MIBI for routine parathyroidectomy in patients with primary hyperparathyroidism when an easily identifiable parathyroid adenoma is localized. PMID:26535821

  20. Staging of Primary Abdominal Lymphomas: Comparison of Whole-Body MRI with Diffusion-Weighted Imaging and 18F-FDG-PET/CT

    PubMed Central

    Stecco, Alessandro; Buemi, Francesco; Quagliozzi, Martina; Lombardi, Mariangela; Santagostino, Alberto; Sacchetti, Gian Mauro; Carriero, Alessandro

    2015-01-01

    Background. The purpose of this study was to compare the accuracy of whole-body MRI with diffusion-weighted sequences (WB-DW-MRI) with that of 18F-FDG-PET/CT in the staging of patients with primary gastrointestinal lymphoma. Methods. This retrospective study involved 17 untreated patients with primary abdominal gastrointestinal lymphoma. All patients underwent 18F-FDG-PET/CT and WB-DW-MRI. Histopathology findings or at least 6 months of clinical and radiological follow-up was the gold standard. The Musshoff-modified Ann Arbor system was used for staging, and diagnostic accuracy was evaluated on a per-node basis. Results. WB-DW-MRI exhibited 100% sensitivity, 96.3% specificity, and 96.1% and 100% positive and negative predictive values (PPV and NPV), respectively. The sensitivity, specificity, and PPV and NPV of PET/CT were 95.9%, 100%, and 100% and 96.4%, respectively. There were no statistically significant differences between the two techniques (p = 0.05). The weighted kappa agreement statistics with a 95% confidence interval were 0.97 (0.95–0.99) between the two MRI readers and 0.87 (0.82–0.92) between the two methods. Conclusions. WB-DW-MRI appears to have a comparable diagnostic value to 18F-FDG-PET/CT in staging patients with gastrointestinal lymphoma. PMID:26798331

  1. Does the Gadoxetic Acid-Enhanced Liver MRI Impact on the Treatment of Patients with Colorectal Cancer? Comparison Study with 18F-FDG PET/CT

    PubMed Central

    Oh, Ji-Won; Oh, Soon Nam; Choi, Joon Il; Choi, Moon Hyung; Yoo, Ie Ryung; Lee, Myung Ah; Yoo, Young-Kyung; Oh, Seong Taek

    2016-01-01

    Objectives. We evaluated the value of Gadoxetic acid-enhanced liver MRI in the preoperative staging of colorectal cancer and estimated the clinical impact of liver MRI in the management plan of liver metastasis. Methods. We identified 108 patients who underwent PET/CT and liver MRI as preoperative evaluation of colorectal cancer, between January 2011 and December 2013. We evaluated the per nodule sensitivity of PET/CT and liver MRI for liver metastasis. Management plan changes were estimated for patients with metastatic nodules newly detected on liver MRI, to assess the clinical impact. Results. We enrolled 131 metastatic nodules (mean size 1.6 cm) in 41 patients (mean age 65 years). The per nodule sensitivities of PET/CT and liver MRI were both 100% for nodules measuring 2 cm or larger but were significantly different for nodules measuring less than 2 cm (59.8% and 95.1%, resp., P = 0.0001). At least one more metastatic nodule was detected on MRI in 16 patients. Among these, 7 patients indicated changes of management plan after performing MRI. Conclusions. Gadoxetic acid-enhanced liver MRI detected more metastatic nodules compared with PET/CT, especially for small (<2 cm) nodules. The newly detected nodules induced management plan change in 43.8% (7/16) of patients. PMID:27022613

  2. Anaesthetic, cardiovascular and respiratory effects of a new steroidal agent CT 1341: a comparison with other intravenous anaesthetic drugs in the unrestrained cat.

    PubMed

    Child, K J; Davis, B; Dodds, M G; Twissell, D J

    1972-10-01

    1. The anaesthetic, cardiovascular, respiratory and adverse effects produced by the intravenous injection of CT 1341, thiopentone, methohexitone, pentobarbitone, propanidid and ketamine have been compared in unrestrained cats prepared with chronically implanted venous and arterial cannulae. Aortic blood pressure and heart rates were monitored before, during and after loss of consciousness.2. CT 1341 produced rapid induction of anaesthesia followed by moderately rapid recovery, was active over a wide range of doses and caused minimal respiratory depression and few adverse effects. It caused an initial short-lasting tachycardia and fall in aortic blood pressure succeeded by a secondary depressor response.3. The safety margin was narrower with the barbiturate drugs than with CT 1341, and large doses induced apnoea and respiratory depression. Small doses of methohexitone elicited excitatory effects and large doses caused severe respiratory and circulatory depression, and recovery from anaesthesia was protracted.4. Propanidid induced short-lasting light anaesthesia. The safety margin was narrowest with this drug and induction was associated with adverse circulatory, respiratory and other effects.5. Ketamine was active over a wide range of doses but exhibited qualitatively different properties from the other anaesthetics. Induction was slower after small doses and these produced circulatory stimulation, catatonia and bizarre behavioural effects. Large doses caused respiratory and circulatory depression and recovery was protracted.6. It is concluded that CT 1341 has a wider therapeutic latitude, produces less respiratory depression and has other advantages over the currently used intravenous anaesthetics. PMID:4651769

  3. Simulated lesion, human observer performance comparison between thin-section dedicated breast CT images versus computed thick-section simulated projection images of the breast

    PubMed Central

    Chen, L; Boone, JM; Abbey, CK; Hargreaves, J; Bateni, C; Lindfors, KK; Yang, K; Nosratieh, A; Hernandez, A; Gazi, P

    2015-01-01

    Objectives The objective of this study was to compare the lesion detection performance of human observers between thin-section computed tomography images of the breast, with thick-section (>40 mm) simulated projection images of the breast. Methods Three radiologists and six physicists each executed a two alterative force choice (2AFC) study involving simulated spherical lesions placed mathematically into breast images produced on a prototype dedicated breast CT scanner. The breast image data sets from 88 patients were used to create 352 pairs of image data. Spherical lesions with diameters of 1, 2, 3, 5, and 11 mm were simulated and adaptively positioned into 3D breast CT image data sets; the native thin section (0.33 mm) images were averaged to produce images with different slice thicknesses; average section thicknesses of 0.33 mm, 0.71 mm, 1.5 mm, and 2.9 mm were representative of breast CT; the average 43 mm slice thickness served to simulate simulated projection images of the breast. Results The percent correct of the human observer’s responses were evaluated in the 2AFC experiments. Radiologists lesion detection performance was significantly (p<0.05) better in the case of thin-section images, compared to thick section images similar to mammography, for all but the 1 mm lesion diameter lesions. For example, the average of three radiologist’s performance for 3 mm diameter lesions was 92 % correct for thin section breast CT images while it was 67 % for the simulated projection images. A gradual reduction in observer performance was observed as the section thickness increased beyond about 1 mm. While a performance difference based on breast density was seen in both breast CT and the projection image results, the average radiologist performance using breast CT images in dense breasts outperformed the performance using simulated projection images in fatty breasts for all lesion diameters except 11 mm. The average radiologist performance outperformed that of the

  4. Comparison of facet joint activity on 99mTc-MDP SPECT/CT with facet joint signal change on MRI with fat suppression

    PubMed Central

    Lehman, Vance T.; Murphy, Robert C.; Schenck, Louis A.; Carter, Rickey E.; Johnson, Geoffrey B.; Kotsenas, Amy L.; Morris, Jonathan M.; Nathan, Mark A.; Wald, John T.; Maus, Timothy P.

    2016-01-01

    PURPOSE We compared signal change on magnetic resonance imaging (MRI) with fat suppression and bone scan activity of lumbar facet joints to determine if these two imaging findings are correlated. METHODS We retrospectively identified all patients who underwent imaging of the lumbar spine for pain evaluation using both technetium-99m methylene disphosphonate single-photon emission computed tomography/computed tomography (99mTc-MDP SPECT/CT) and MRI with at least one fat-suppressed T2- or T1-weighted sequence with gadolinium enhancement within a 180-day interval, at our institution between 1 January 2008 and 19 February 2013. Facet joint activity on 99mTc-MDP SPECT/CT and peri-facet signal change on MRI were rated as normal or increased. Agreement between the two examination types were determined with the κ and prevalence-adjusted bias-adjusted κ (PABAK) statistics. RESULTS This study included 60 patients (28 male, 47%), with a mean age of 49±19.7 years (range, 12–93 years). The κ value indicated no agreement between 99mTc-MDP SPECT/CT and MRI (κ=−0.026; 95% confidence interval: −0.051, 0.000). The PABAK values were fair to high at each spinal level, which suggests that relatively low disease prevalence lowered the κ values. Together, the κ and PABAK values indicate that there is some degree of intermodality agreement, but that it is not consistent. CONCLUSION Overall, facet joint signal change on fat-suppressed MRI did not always correlate with increased 99mTc-MDP SPECT/CT activity. MRI and 99mTc-MDP SPECT/CT for facet joint evaluation should not be considered interchangeable examinations in clinical practice or research. PMID:27035592

  5. The extension of a uniform canopy reflectance model to include row effects

    NASA Technical Reports Server (NTRS)

    Suits, G. H. (Principal Investigator)

    1981-01-01

    The effect of row structure is assumed to be caused by the variation in density of vegetation across rows rather than to a profile in canopy height. The calculation of crop reflectance using vegetation density modulation across rows follows a parallel procedure to that for a uniform canopy. Predictions using the row model for wheat show that the effect of changes in sun to row azimuth are greatest in Landsat Band 5 (red band) and can result in underestimation of crop vigor.

  6. [CT fluoroscopy].

    PubMed

    Rogalla, P; Juran, R

    2004-07-01

    Percutaneous biopsy of pulmonary nodules requires precise needle placement, with the goal of attaining a secure position of the needle for therapeutic or diagnostic purposes as quickly as possible and with minimal tissue damage along the access route. The requirements from the image guidance system during the intervention are, in addition to universal applicability, a quick reaction time and a user-friendly interface. CT fluoroscopy fulfils these requirements, although radiation protection for the patient and radiologist becomes an important issue. PMID:15232690

  7. MRI-based IMRT planning for MR-linac: comparison between CT- and MRI-based plans for pancreatic and prostate cancers.

    PubMed

    Prior, Phil; Chen, Xinfeng; Botros, Maikel; Paulson, Eric S; Lawton, Colleen; Erickson, Beth; Li, X Allen

    2016-05-21

    The treatment planning in radiation therapy (RT) can be arranged to combine benefits of computed tomography (CT) and magnetic resonance imaging (MRI) together to maintain dose calculation accuracy and improved target delineation. Our aim is study the dosimetric impact of uniform relative electron density assignment on IMRT treatment planning with additional consideration given to the effect of a 1.5 T transverse magnetic field (TMF) in MR-Linac. A series of intensity modulated RT (IMRT) plans were generated for two representative tumor sites, pancreas and prostate, using CT and MRI datasets. Representative CT-based IMRT plans were generated to assess the impact of different electron density (ED) assignment on plan quality using CT without the presence of a 1.5 T TMF. The relative ED (rED) values used were taken from the ICRU report 46. Four types of rED assignment in the organs at risk (OARs), the planning target volumes (PTV) and in the non-specified tissue (NST) were considered. Dose was recalculated (no optimization) using a Monaco 5.09.07a research planning system employing Monte Carlo calculations with an option to include TMF. To investigate the dosimetric effect of different rED assignment, the dose-volume parameters (DVPs) obtained from these specific rED plans were compared to those obtained from the original plans based on CT. Overall, we found that uniform rED assignment results in differences in DVPs within 3% for the PTV and 5% for OAR. The presence of 1.5 T TMF on IMRT DVPs resulted in differences that were generally within 3% of the Gold St for both the pancreas and prostate. The combination of uniform rED assignment and TMF produced differences in DVPs that were within 4-5% of the Gold St. Larger differences in DVPs were observed for OARs on T2-based plans. The effects of using different rED assignments and the presence of 1.5 T TMF for pancreas and prostate IMRT plans are generally within 3% and 5% of PTV and OAR Gold St values. There are

  8. Radiation dose reduction to the breast in thoracic CT: Comparison of bismuth shielding, organ-based tube current modulation, and use of a globally decreased tube current

    SciTech Connect

    Wang Jia; Duan Xinhui; Christner, Jodie A.; Leng Shuai; Yu Lifeng; McCollough, Cynthia H.

    2011-11-15

    Purpose: The purpose of this work was to evaluate dose performance and image quality in thoracic CT using three techniques to reduce dose to the breast: bismuth shielding, organ-based tube current modulation (TCM) and global tube current reduction. Methods: Semi-anthropomorphic thorax phantoms of four different sizes (15, 30, 35, and 40 cm lateral width) were used for dose measurement and image quality assessment. Four scans were performed on each phantom using 100 or 120 kV with a clinical CT scanner: (1) reference scan; (2) scan with bismuth breast shield of an appropriate thickness; (3) scan with organ-based TCM; and (4) scan with a global reduction in tube current chosen to match the dose reduction from bismuth shielding. Dose to the breast was measured with an ion chamber on the surface of the phantom. Image quality was evaluated by measuring the mean and standard deviation of CT numbers within the lung and heart regions. Results: Compared to the reference scan, dose to the breast region was decreased by about 21% for the 15-cm phantom with a pediatric (2-ply) shield and by about 37% for the 30, 35, and 40-cm phantoms with adult (4-ply) shields. Organ-based TCM decreased the dose by 12% for the 15-cm phantom, and 34-39% for the 30, 35, and 40-cm phantoms. Global lowering of the tube current reduced breast dose by 23% for the 15-cm phantom and 39% for the 30, 35, and 40-cm phantoms. In phantoms of all four sizes, image noise was increased in both the lung and heart regions with bismuth shielding. No significant increase in noise was observed with organ-based TCM. Decreasing tube current globally led to similar noise increases as bismuth shielding. Streak and beam hardening artifacts, and a resulting artifactual increase in CT numbers, were observed for scans with bismuth shields, but not for organ-based TCM or global tube current reduction. Conclusions: Organ-based TCM produces dose reduction to the breast similar to that achieved with bismuth shielding for

  9. MRI-based IMRT planning for MR-linac: comparison between CT- and MRI-based plans for pancreatic and prostate cancers

    NASA Astrophysics Data System (ADS)

    Prior, Phil; Chen, Xinfeng; Botros, Maikel; Paulson, Eric S.; Lawton, Colleen; Erickson, Beth; Li, X. Allen

    2016-05-01

    The treatment planning in radiation therapy (RT) can be arranged to combine benefits of computed tomography (CT) and magnetic resonance imaging (MRI) together to maintain dose calculation accuracy and improved target delineation. Our aim is study the dosimetric impact of uniform relative electron density assignment on IMRT treatment planning with additional consideration given to the effect of a 1.5 T transverse magnetic field (TMF) in MR-Linac. A series of intensity modulated RT (IMRT) plans were generated for two representative tumor sites, pancreas and prostate, using CT and MRI datasets. Representative CT-based IMRT plans were generated to assess the impact of different electron density (ED) assignment on plan quality using CT without the presence of a 1.5 T TMF. The relative ED (rED) values used were taken from the ICRU report 46. Four types of rED assignment in the organs at risk (OARs), the planning target volumes (PTV) and in the non-specified tissue (NST) were considered. Dose was recalculated (no optimization) using a Monaco 5.09.07a research planning system employing Monte Carlo calculations with an option to include TMF. To investigate the dosimetric effect of different rED assignment, the dose-volume parameters (DVPs) obtained from these specific rED plans were compared to those obtained from the original plans based on CT. Overall, we found that uniform rED assignment results in differences in DVPs within 3% for the PTV and 5% for OAR. The presence of 1.5 T TMF on IMRT DVPs resulted in differences that were generally within 3% of the Gold St for both the pancreas and prostate. The combination of uniform rED assignment and TMF produced differences in DVPs that were within 4–5% of the Gold St. Larger differences in DVPs were observed for OARs on T2-based plans. The effects of using different rED assignments and the presence of 1.5 T TMF for pancreas and prostate IMRT plans are generally within 3% and 5% of PTV and OAR Gold St values. There are

  10. 7 CFR 810.204 - Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... barley and Six-rowed Blue Malting barley. 810.204 Section 810.204 Agriculture Regulations of the... Standards for Barley Principles Governing the Application of Standards § 810.204 Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley. Grade Minimum limits of—...

  11. 7 CFR 810.204 - Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... barley and Six-rowed Blue Malting barley. 810.204 Section 810.204 Agriculture Regulations of the... Standards for Barley Principles Governing the Application of Standards § 810.204 Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley. Grade Minimum limits of—...

  12. 7 CFR 810.204 - Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... barley and Six-rowed Blue Malting barley. 810.204 Section 810.204 Agriculture Regulations of the... Standards for Barley Principles Governing the Application of Standards § 810.204 Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley. Grade Minimum limits of—...

  13. 7 CFR 810.204 - Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... barley and Six-rowed Blue Malting barley. 810.204 Section 810.204 Agriculture Regulations of the... Standards for Barley Principles Governing the Application of Standards § 810.204 Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley. Grade Minimum limits of—...

  14. 7 CFR 810.204 - Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... barley and Six-rowed Blue Malting barley. 810.204 Section 810.204 Agriculture Regulations of the... Standards for Barley Principles Governing the Application of Standards § 810.204 Grades and grade requirements for Six-rowed Malting barley and Six-rowed Blue Malting barley. Grade Minimum limits of—...

  15. Organ doses, effective doses, and risk indices in adult CT: Comparison of four types of reference phantoms across different examination protocols

    SciTech Connect

    Zhang Yakun; Li Xiang; Paul Segars, W.; Samei, Ehsan

    2012-06-15

    Purpose: Radiation exposure from computed tomography (CT) to the public has increased the concern among radiation protection professionals. Being able to accurately assess the radiation dose patients receive during CT procedures is a crucial step in the management of CT dose. Currently, various computational anthropomorphic phantoms are used to assess radiation dose by different research groups. It is desirable to better understand how the dose results are affected by different choices of phantoms. In this study, the authors assessed the uncertainties in CT dose and risk estimation associated with different types of computational phantoms for a selected group of representative CT protocols. Methods: Routinely used CT examinations were categorized into ten body and three neurological examination categories. Organ doses, effective doses, risk indices, and conversion coefficients to effective dose and risk index (k and q factors, respectively) were estimated for these examinations for a clinical CT system (LightSpeed VCT, GE Healthcare). Four methods were used, each employing a different type of reference phantoms. The first and second methods employed a Monte Carlo program previously developed and validated in our laboratory. In the first method, the reference male and female extended cardiac-torso (XCAT) phantoms were used, which were initially created from the Visible Human data and later adjusted to match organ masses defined in ICRP publication 89. In the second method, the reference male and female phantoms described in ICRP publication 110 were used, which were initially developed from tomographic data of two patients and later modified to match ICRP 89 organ masses. The third method employed a commercial dosimetry spreadsheet (ImPACT group, London, England) with its own hermaphrodite stylized phantom. In the fourth method, another widely used dosimetry spreadsheet (CT-Expo, Medizinische Hochschule, Hannover, Germany) was employed together with its associated

  16. Validated biomechanical model for efficiency and speed of rowing.

    PubMed

    Pelz, Peter F; Vergé, Angela

    2014-10-17

    The speed of a competitive rowing crew depends on the number of crew members, their body mass, sex and the type of rowing-sweep rowing or sculling. The time-averaged speed is proportional to the rower's body mass to the 1/36th power, to the number of crew members to the 1/9th power and to the physiological efficiency (accounted for by the rower's sex) to the 1/3rd power. The quality of the rowing shell and propulsion system is captured by one dimensionless parameter that takes the mechanical efficiency, the shape and drag coefficient of the shell and the Froude propulsion efficiency into account. We derive the biomechanical equation for the speed of rowing by two independent methods and further validate it by successfully predicting race times. We derive the theoretical upper limit of the Froude propulsion efficiency for low viscous flows. This upper limit is shown to be a function solely of the velocity ratio of blade to boat speed (i.e., it is completely independent of the blade shape), a result that may also be of interest for other repetitive propulsion systems. PMID:25189093

  17. On the origin of Spanish two-rowed barleys.

    PubMed

    Moralejo, M; Romagosa, I; Salcedo, G; Sánchez-Monge, R; Molina-Cano, J L

    1994-02-01

    To investigate the phylogenetic origin of Spanish two-rowed barleys, we studied 44 accessions of old land-races both morphologically and biochemically to ascertain their similarity with 51 entries of old cultivars and land-races of widespread origin across Europe. They were also compared with 20 accessions of Hordeum spontaneum from the Mediterranean basin and other regions of its distribution range, 14 accessions of Moroccan cultivated six-rowed barley land-races, and different six-rowed Spanish and two-and six-rowed European cultivars. CM-(trypsin inhibitors and subunits of the barley tetrameric α-amylase inhibitor) proteins and hordeins, all of which are endosperm proteins, were used as biochemical markers. The appearance of separate clusters of the Spanish barleys in the numerical classifications for both protein systems as a result of the existence of characteristic gene combinations that do not exist in entries from other origins permitted us to postulate the existence of local ancestors for most of the Spanish two-rowed barleys studied, and, therefore, a possible in situ domestication. PMID:24190469

  18. Influence of Ergometer Design on Physiological Responses during Rowing.

    PubMed

    Rossi, J; Piponnier, E; Vincent, L; Samozino, P; Messonnier, L

    2015-11-01

    The aim of this study was to compare the physiological responses and rowing efficiency on 2 different rowing ergometers: stationary vs. dynamic ergometers manufactured by Concept2. 11 oarswomen and oarsmen rowed 4 min at 60% and 70% of peak power output on both ergometers (randomized order). Power output, stroke rate, heart rate, oxygen uptake, carbon dioxide production, lactate accumulation and rating of perceived exertion were recorded at each stage on the 2 ergometers. Gross and net efficiencies were computed. Exercise intensity was associated with increases in all parameters. Rowing on dynamic ergometer was associated with higher heart rate, oxygen uptake, carbon dioxide production and stroke rate, concomitantly to lower blood lactate accumulation but also to lower gross and net efficiencies. The present study showed that rowing efficiency and blood lactate accumulation were lower on the Concept2 dynamic ergometer than on its stationary counterpart. If the use of the Concept2 dynamic ergometer may provide some advantages (reduced risk of injuries), its utilization requires a specific evaluation of physiological responses during an incremental exercise for an adapted management of training. PMID:26212249

  19. Comparison of aPTT and CT Parameter of the ROTEM Test to Monitor Heparin Anti-Coagulation Effect in ICU Patients: an Observational Study.

    PubMed

    Najafi, Atabak; Nikeish, Masoomeh; Etezadi, Farhad; Pourfakhr, Pejman; Imani, Farsad; Khajavi, Mohammad Reza; Shariat Moharari, Reza

    2015-10-01

    Heparin is frequently used in different clinical settings to reduce the coagulating ability of the blood. Because of probable adverse effects owing to heparin therapy and regarding variability of patients' responses to heparin, which make it very unreliable, it seems prudent to monitor meticulously its effects on the human body. There are a lot of laboratory tests to watch its effects on the body for example; aPTT and ROTEM are the most widely used tests that are performed today. We aimed to compare the aPTT test results against changes of CT parameter of the ROTEM test due to heparin administration. This study was conducted on 45 critically ill patients who needed to receive heparin according to their clinical status. All patients received 550 to 1500 unit heparin per hour (on average 17.5 unit heparin per kilogram weight). While the patients were under infusion of heparin, two blood samples (5 ml) were taken from a newly established cubital vein, just five hours after commencement of heparin therapy. One sample was used for aPTT and the other one for ROTEM. The correlation between aPTT and the changes of CT parameter of the ROTEM with heparin dosage and infusion was the primary outcome. The correlation between heparin therapy and the changes of other parameters like MCF, CFT, and a number of platelets were the secondary outcome of the study. The only significant correlation was between changes of CT and aPTT (P=0.000). The other variables were not correlated. Changes of CT parameter of ROTEM test can be used for monitoring of reduced coagulability during heparin infusion instead of aPTT test. PMID:26615378

  20. Comparison of radionuclide (RN), computed tomography (CT) and magnetic resonance (MR) imaging of a vascular necrosis (AVN) of the hip using receiver operator characteristic (ROC) curves

    SciTech Connect

    Alavi, A.; Kundel, H.; Mitchell, M.; Velchik, M.; Makler, T.; Steinberg, M.; Kressel, H.

    1985-05-01

    The diagnostic accuracy of RN, CT, and MR imaging for AVN was determined retrospectively using ROC curves. The abnormal images were drawn from 35 patients who had proven AVN. The MR images were made using an experimental GE resistive magnet operating at 0.12 Tesla corresponding to a proton resonant of 5.1 MHz. Most of the CT images were made using a GE 9800 CT Scanner. RN images were obtained using 99m-Tc MDP. Planar as well as pinhole images of both hips were acquired on each case. Three test sets, one for each modality was assembled. Each of the imaging modalities had a sensitivity of 85%, and a specificity of 85% at the optimal point on the ROC curve. These data demonstrates that MR imaging is not significantly different from other modalities for discrimination between AVN and normal hips. The test set did not include patients with disease other than AVN. The authors are planning to perform a blinded prospective study for more definitive results.

  1. Application of F-18-Sodium Fluoride (NaF) Dynamic PET-CT (dPET-CT) for Defect Healing: A Comparison of Biomaterials in an Experimental Osteoporotic Rat Model

    PubMed Central

    Cheng, Caixia; Alt, Volker; Pan, Leyun; Thormann, Ulrich; Schnettler, Reinhard; Strauss, Ludwig G.; Heinemann, Sascha; Schumacher, Matthias; Gelinsky, Michael; Nies, Berthold; Dimitrakopoulou-Strauss, Antonia

    2014-01-01

    Background The aim of the current study was to measure and compare the effect of various biomaterials for the healing of osteoporotic bone defects in the rat femur using 18F-sodium fluoride dPET-CT. Material/Methods Osteoporosis was induced by ovariectomy and a calcium-restricted diet. After 3 months, rats were operated on to create a 4-mm wedge-shaped defect in the distal metaphyseal femur. Bone substitution materials of calcium phosphate cement (CPC), composites of collagen and silica, and iron foams with interconnecting pores were inserted. Strontium or bisphosphonate, which are well known for having positive effects in osteoporosis treatment, were added into the materials. Eighteen weeks after osteoporosis induction and 6 weeks following femoral surgery, dPET-CT studies scan were performed with 18F-Sodium Fluoride. Standardized uptake values (SUVs) and a 2-tissue compartmental learning-machine model (K1-k4, vessel density [VB], influx [ki]) were used for quantitative analysis. Results k3, reflecting the formation of fluoroapatite, revealed a statistically significant increase at the biomaterial-bone interface due to the Sr release from strontium-modified calcium phosphate cement (SrCPC) compared to CPC, which demonstrated enhanced new bone formation. In addition, k3 as measured in the porous scaffold silica/collagen xerogel (Sc-B30), showed a significant increase based on Wilcoxon rank-sum test (p<0.05) as compared with monolithic silica/collagen xerogel (B30) in the defect region. Furthermore, ki, reflecting the net plasma clearance of tracer to bone mineral measured in the iron foam with coating of the bisphosphonate zoledronic acid (Fe-BP), was enhanced as compared with plain iron foam (Fe) in the defect region. Conclusions k3 was the most significant parameter for the characterization of healing processes and revealed the best differentiation between the 2 different biomaterials. PET scanning using 18F-sodium fluoride seems to be a sensitive and useful

  2. A parallelization of the row-searching algorithm

    NASA Astrophysics Data System (ADS)

    Yaici, Malika; Khaled, Hayet; Khaled, Zakia; Bentahar, Athmane

    2012-11-01

    The problem dealt in this paper concerns the parallelization of the row-searching algorithm which allows the search for linearly dependant rows on a given matrix and its implementation on MPI (Message Passing Interface) environment. This algorithm is largely used in control theory and more specifically in solving the famous diophantine equation. An introduction to the diophantine equation is presented, then two parallelization approaches of the algorithm are detailed. The first distributes a set of rows on processes (processors) and the second makes a distribution per blocks. The sequential algorithm and its two parallel forms are implemented using MPI routines, then modelled using UML (Unified Modelling Language) and finally evaluated using algorithmic complexity.

  3. Numerical study of rowing hydrofoil performance at low Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Chung, M.-H.

    2008-04-01

    In this paper, the hydrodynamic performance of a 2-D flat-plate hydrofoil in rowing motion is numerically studied by a Cartesian grid method with the cut-cell approach. Adaptive mesh refinement is used to save on the number of mesh cells without harming spatial resolution in critical regions. The rowing kinematics of the hydrofoil is the same for all simulations in this work. The design parameters studied are the reduced frequency of the rowing motion, the heave amplitude, and the time lags of the feathered-to-broadside rotation and the broadside-to-feathered rotation. Results show that larger thrust and efficiency can be attained if the feathered-to-broadside rotation is started right after the beginning of the power stroke and the broadside-to-feathered rotation is finished right before the end of the power stroke. Finally, both the thrust and the efficiency increase with Reynolds number.

  4. Nutrition and Supplements for Elite Open-Weight Rowing.

    PubMed

    Boegman, Susan; Dziedzic, Christine E

    2016-01-01

    Competitive rowing events are raced over 2,000 m requiring athletes to have highly developed aerobic and anaerobic systems. Elite rowers therefore undertake training sessions focused on lactate tolerance, strength and power as well as aerobic and anaerobic capacity development, that can amount to a 24-h training week. The training stimuli and consequent metabolic demands of each session in a rowing training program differ depending on type, length, and intensity. Nutrition guidelines for endurance- and power-based sports should be drawn upon; however, individualized and flexible nutrition plans are critical to successfully meet the daily, weekly, and cyclic nutrient requirements of a rower. This review will provide an overview of key nutritional strategies to optimize training and enhance adaptation, and briefly discuss supplement strategies that may support health and enhance performance in elite rowing. PMID:27399822

  5. SU-E-T-86: Comparison of Two Commercially Available Programs for the Evaluation of Delivered Daily Dose Using Cone Beam CT (CBCT)

    SciTech Connect

    Tuohy, R; Bosse, C; Mavroidis, P; Shi, Z; Crownover, R; Papanikolaou, N; Stathakis, S

    2014-06-01

    Purpose: In this study, two commercially available programs were compared for the evaluation of delivered daily dose using cone beam CT (CBCT). Methods: Thirty (n=30) patients previously treated in our clinic (10 prostate, 10 SBRT lung and 10 abdomen) were used in this study. The patients' plans were optimized and calculated using the Pinnacle treatment planning system. The daily CBCT scans were imported into Velocity and RayStation along with the corresponding planning CTs, structure sets and 3D dose distributions for each patient. The organs at risk (OAR) were contoured on each CBCT by the prescribing physician and were included in the evaluation of the daily delivered dose. Each CBCT was registered to the planning CT, once with rigid registration and then again, separately, with deformable registration. After registering each CBCT, the dose distribution from the planning CT was overlaid and the dose volume histograms (DVH) for the OAR and the planning target volumes (PTV) were calculated. Results: For prostate patients, we observed daily volume changes for the OARs. The DVH analysis for those patients showed variation in the sparing of the OARs while PTV coverage remained virtually unchanged using both Velocity and RayStation systems. Similar results were observed for abdominal patients. In contrast, for SBRT lung patients, the DVH for the OARs and target were comparable to those from the initial treatment plan. Differences in organ volume and organ doses were also observed when comparing the daily fractions using deformable and rigid registrations. Conclusion: By using daily CBCT dose reconstruction, we proved PTV coverage for prostate and abdominal targets is adequate. However, there is significant dosimetric change for the OARs. For lung SBRT patients, the delivered daily dose for both PTV and OAR is comparable to the planned dose with no significant differences.

  6. Inhibition of fibrosis and inflammation by triple therapy with pirfenidone, edaravone and erythropoietin in rabbits with drug-induced lung injury: comparison of CT imaging and pathological findings.

    PubMed

    Watanabe, Shobu; Nitta, Norihisa; Sonoda, Akinaga; Nitta-Seko, Ayumi; Ohta, Shinichi; Tsuchiya, Keiko; Otani, Hideji; Tomozawa, Yuki; Nagatani, Yukihiro; Mukaisho, Kenichi; Takahashi, Masashi; Murata, Kiyoshi

    2013-11-01

    In a rabbit model of bleomycin-induced lung injury, computed tomography (CT) and pathological studies were conducted to investigate whether the progression of this injury is inhibited by pirfenidone and by triple therapy with pirfenidone, edaravone and erythropoietin. We divided nine rabbits with bleomycin-induced lung injury into three equally sized groups. Group 1 served as the control, group 2 received pirfenidone alone and group 3 was treated with pirfenidone, edaravone and erythropoietin. Multidetector CT (MDCT) scans were acquired immediately after the administration of bleomycin, and further scans were performed on days 14 and 28. The area of abnormal opacity was calculated. The rabbit lungs were removed and the size of abnormal areas in macroscopic specimens was calculated and the degree of fibrosis and inflammation in microscopic specimens was scored. In order, the average size of the area of abnormal opacity on CT scans was largest in group 1, followed by groups 2 and 3. On day 28, the area of opacity was significantly smaller in group 3 than in group 1 (P=0.071). The average size of the area of abnormal opacity on macroscopic findings was largest in group 1, followed in order by groups 2 and 3; the difference between group 1 and 3 was significant (P<0.05). The average fibrosis score was highest in group 3 followed by groups 2 and 1. By contrast, the average inflammation score was highest in group 2 followed by groups 1 and 3. Although the administration of pirfenidone alone slowed the progression of bleomycin-induced lung injury, the triple-drug combination was more effective. PMID:24223628

  7. [The features of adults' coronary artery anomalies shown by 64-multi-detector rows CT].

    PubMed

    Yuan, Zhentuan; Yu, Jianqun; Zhang, Youyi; Yuan, Hongmei

    2009-06-01

    To analyze the adults' coronary artery anomalies revealed by 64-MDCT, we retrospectively analyzed 34 cases of coronary artery anomalies (26 males and 8 females, averagely aged 53. 4 years with a range from 30 to 72 years). Multi-plannar reconstruction (MPR), maximum intensity projection (MIP), surface shadow display (SSD) and volume rendering (VR) were used to demonstrate the anomalous coronary artery. We found 4 cases of RCA from the left coronary sinus, 8 cases with secondary RCA, 1 case with high locations of left main (LM) segments from left sinus of valves, 1 case with LAD originated from main pulmonary artery, 3 cases with separate origin of LAD and LCX. Ten cases with myocardial bridge were shown (9 cases in LAD, 1 case in LCX); coronary fistula was seen in 2 cases (one was RCA-RA fistula, another was LAD-RV fistula), coronary aneurysm was found in 2 cases. Three cases in RCA were short and small. In conclusion, 64-MDCT is a good choice for diagnosing the anomalous coronary artery. PMID:19634659

  8. EB curing and cure grafting of novel CT monomer complexes: comparison with UV process and extension of the technique to thiol-ene systems

    NASA Astrophysics Data System (ADS)

    Dennis, Gary R.; Garnett, John L.; Zilic, Elvis

    2004-09-01

    EB curing and cure grafting of charge transfer (CT) monomer complexes is discussed. The complexes studied involve representative donors (D) such as vinyl ethers and typical acceptors (A) including maleates, maleimides and acrylates also oligomers. The EB results are compared with UV curing and cure grafting of the same complexes. The work has been extended to include EB/UV curing and cure grafting of thiol-ene systems. The significance of these results in the potential commercial application of these complexes is discussed.

  9. Effect of contrast magnitude and resolution metric on noise-resolution tradeoffs in x-ray CT imaging: a comparison of non-quadratic penalized alternating minimization and filtered backprojection algorithms

    NASA Astrophysics Data System (ADS)

    Evans, Joshua D.; Politte, David G.; Whiting, Bruce R.; O'Sullivan, Joseph A.; Williamson, Jeffrey F.

    2011-03-01

    Purpose: To assess the impact of contrast magnitude and spatial resolution metric choices on the noise-resolution tradeoff of a non-quadratic penalized statistical iterative algorithm, Alternating Minimization (AM), in x-ray transmission CT. Methods: Monoenergetic Poisson-counting CT data were simulated for a water phantom containing circular inserts of varying contrast (7% to 238%). The data was reconstructed with conventional filtered backprojection (FBP) and two non-quadratic penalty parameterizations of AM. A range of smoothing strengths is reconstructed for each algorithm to quantify the noise-resolution tradeoff curve. Modulation transfer functions (MTFs) were estimated from the circular contrast-insert edges and then integrated up to a cutoff frequency as a single-parameter measure of local spatial resolution. Two cutoff frequencies and two resolution comparison values are investigated for their effect on reported tradeoff advantage. Results: The noise-resolution tradeoff curve was always more favorable for AM than FBP. For strongly edge-preserving penalty functions, this advantage was found to be dependent upon the contrast for which resolution is quantified for comparison. The magnitude of the reported dose reduction potential of the AM algorithm was shown to be dependent on the resolution metric choices, though the general contrast-dependence was always evident. Conclusions: The penalized AM algorithm shows the potential to reconstruct images of comparable quality using a fraction of the dose required by FBP. The contrast-dependence on the tradeoff advantage implies that statistical algorithms using non-quadratic penalty functions should be assessed using contrasts relevant to the intended clinical task.

  10. INVESTIGATION OF PARTIAL VOLUME EFFECT IN DIFFERENT PET/CT SYSTEMS: A COMPARISON OF RESULTS USING THE MADEIRA PHANTOM AND THE NEMA NU-2 2001 PHANTOM.

    PubMed

    Chipiga, L; Sydoff, M; Zvonova, I; Bernhardsson, C

    2016-06-01

    Positron emission tomography combined with computed tomography (PET/CT) is a quantitative technique used for diagnosing various diseases and for monitoring treatment response for different types of tumours. However, the accuracy of the data is limited by the spatial resolution of the system. In addition, the so-called partial volume effect (PVE) causes a blurring of image structures, which in turn may cause an underestimation of activity of a structure with high-activity content. In this study, a new phantom, MADEIRA (Minimising Activity and Dose with Enhanced Image quality by Radiopharmaceutical Administrations) for activity quantification in PET and single photon emission computed tomography (SPECT) was used to investigate the influence on the PVE by lesion size and tumour-to-background activity concentration ratio (TBR) in four different PET/CT systems. These measurements were compared with data from measurements with the NEMA NU-2 2001 phantom. The results with the MADEIRA phantom showed that the activity concentration (AC) values were closest to the true values at low ratios of TBR (<10) and reduced to 50 % of the actual AC values at high TBR (30-35). For all scanners, recovery of true values became closer to 1 with an increasing diameter of the lesion. The MADEIRA phantom showed good agreement with the results obtained from measurements with the NEMA NU-2 2001 phantom but allows for a wider range of possibilities in measuring image quality parameters. PMID:26940437

  11. Hemodynamic Changes Caused by Flow Diverters in Rabbit Aneurysm Models: Comparison of Virtual and Realistic FD Deployments Based on Micro-CT Reconstruction

    PubMed Central

    Fang, Yibin; Yu, Ying; Cheng, Jiyong; Wang, Shengzhang; Wang, Kuizhong; Liu, Jian-Min; Huang, Qinghai

    2013-01-01

    Adjusting hemodynamics via flow diverter (FD) implantation is emerging as a novel method of treating cerebral aneurysms. However, most previous FD-related hemodynamic studies were based on virtual FD deployment, which may produce different hemodynamic outcomes than realistic (in vivo) FD deployment. We compared hemodynamics between virtual FD and realistic FD deployments in rabbit aneurysm models using computational fluid dynamics (CFD) simulations. FDs were implanted for aneurysms in 14 rabbits. Vascular models based on rabbit-specific angiograms were reconstructed for CFD studies. Real FD configurations were reconstructed based on micro-CT scans after sacrifice, while virtual FD configurations were constructed with SolidWorks software. Hemodynamic parameters before and after FD deployment were analyzed. According to the metal coverage (MC) of implanted FDs calculated based on micro-CT reconstruction, 14 rabbits were divided into two groups (A, MC >35%; B, MC <35%). Normalized mean wall shear stress (WSS), relative residence time (RRT), inflow velocity, and inflow volume in Group A were significantly different (P<0.05) from virtual FD deployment, but pressure was not (P>0.05). The normalized mean WSS in Group A after realistic FD implantation was significantly lower than that of Group B. All parameters in Group B exhibited no significant difference between realistic and virtual FDs. This study confirmed MC-correlated differences in hemodynamic parameters between realistic and virtual FD deployment. PMID:23823503

  12. Effect of row orientation on energy balance components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solar irradiance is the primary source of energy that is converted into sensible and latent heat fluxes in the soil-plant-atmosphere continuum. The orientation of agricultural crop rows relative to the sun’s zenith angle determines the amount of solar irradiance reaching the plant and soil surfaces...

  13. 1. Elevator row at Duluth. Rice's Point showing context of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Elevator row at Duluth. Rice's Point showing context of Peavey Duluth Terminal and Occident Terminal. - Peavey Duluth Terminal Elevator, South side of first slip, north from outer end of Rice's Point, east of Garfield Avenue, Duluth, St. Louis County, MN

  14. Cotton Response to Herbicide Technologies, Row Patterns, and Tillage Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton producers must make decisions related to cotton varieties, herbicide systems, tillage systems, and row patterns. A study was conducted to compare a conventional variety, a glyphosate tolerant variety, and a glufosinate tolerant variety in both conventional tillage and conservation tillage sys...

  15. A mathematical model concerning reflectance from a row crop

    NASA Technical Reports Server (NTRS)

    Jaggi, R. K.

    1972-01-01

    The recent work of Allen, Gayle, and Richardson (1970) and Suits (1972) has been extended to compute directional reflectance from a crop row. A model is constructed which takes into account edge effects and aids in discriminating crops with leaf orientation in preferred directions. This report only contains the development of the mathematical equations. Numerical results will be published in a forthcoming report.

  16. Reeling in the textiles at Row Clothing Enterprises

    SciTech Connect

    Ridgley, H.

    1997-12-01

    While a handful of textile processing centers in operation today can date their roots back to the turn of this century or before, Row Clothing Enterprises (Baltimore) first opened its doors in 1985. Soon after, it climbed its way to becoming one of the premier textile processing businesses in the country. And what they want most of all is usable clothing--the discards of American secondhand clothing stores. The company exports 100% of the usable clothing it recovers paying institutions as much as $150 a ton for the material. Graders also sort the material into piles headed for the mutilating, or fiber-shredding, machine. While not all the material is shredded, it does provide more opportunities for resale. Whatever Row cannot resell as clothing--because it is soiled or torn--gets processed into industrial wiping cloths, if it is cotton. Clothing made from wool and polyester is sent to woolen and polyester fiber mills to be made into new clothing. While 80% of Row`s wiper market is domestic, 80% of its fiber market is overseas.

  17. Relation of baseflow to row crop intensity in Iowa

    USGS Publications Warehouse

    Schilling, K.E.

    2005-01-01

    Increasing baseflow and baseflow percentage over the second half of the 20th century in Iowa has contributed to increasing nitrate-nitrogen concentrations measured in Iowa rivers because nitrate is primarily delivered to streams as baseflow and tile drainage. The relation of baseflow and baseflow percentage to row crop land use was evaluated for 11 Iowa rivers and their watersheds for their period of streamflow record (58-73 years period). Results indicated increasing baseflow in Iowa's rivers is significantly related to increasing row crop intensity. A 13-52% increase in row crop percentage in many Iowa watersheds has contributed to an increase of 33-135 mm increase in baseflow and 7-31% increase in baseflow percentage. Limited historical water quality data from two larger Iowa rivers (Cedar and Raccoon rivers) suggest that increasing row crop land use over the 20th century has produced more baseflow and contributed to increasing nitrate concentrations in Iowa's rivers. ?? 2004 Elsevier B.V. All rights reserved.

  18. Poverty and Sex Relationships in a "Skid Row" Slum

    ERIC Educational Resources Information Center

    Kuttner, Robert E.

    1971-01-01

    The article concludes that the difference between skid row and middle class women is not in standards, essentially, but in success in adhering to standards. Though this difference may be due to inherited qualities that make these women more vulnerable, a portion of the blame rests with society. (Author)

  19. Human Service Strategy in an Urban Skid Row.

    ERIC Educational Resources Information Center

    Hobfoll, S.E.; And Others

    1981-01-01

    Studies changes in the physical and social composition of Skid Row. Results indicate multiple agency users were found to have a greater alcohol problem and to be more socially isolated than nonagency users. Multiple agency users were very much in need of subsistence level support and health maintenance. (Author)

  20. 8. Photocopy of c. 1906 photograph looking SE at row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Photocopy of c. 1906 photograph looking SE at row of workers' housing along Main Street; bell calling workers to work is mounted on pole at left, corner of locomotive shed at right. - Laurel Valley Sugar Plantation, Double Creole Quarters, 2 Miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  1. 1. Photocopy of c. 1906 photograph of row Creole T ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Photocopy of c. 1906 photograph of row Creole T houses across from mill pond that were available to skilled workers including engineers. - Laurel Valley Sugar Plantation, Engineer's House, 2 Miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  2. Nutrient Losses from Row Crop Agriculture in Indiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Topic: USDA CEAP: Research Results and Recommendations Nutrient losses from row crop agriculture are known to contribute to water quality problems such as eutrophication and the zone of hypoxia in the Gulf of Mexico. Fields and catchments in the Cedar Creek sub-watershed of the St. Joseph River ba...

  3. 102. VIEW OF WEST ROW OF CABINETS IN LANDLINE INSTRUMENTATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    102. VIEW OF WEST ROW OF CABINETS IN LANDLINE INSTRUMENTATION ROOM (106), LSB (BLDG. 770). LOGIC CONTROL AND MONITOR UNITS BOOSTER AND FUEL SYSTEMS ON LEFT; LANDLINE SIGNAL CONDITIONERS ON RIGHT. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  4. Power, Consent and Resistance: An Autoethnography of Competitive Rowing

    ERIC Educational Resources Information Center

    Purdy, Laura; Potrac, Paul; Jones, Robyn

    2008-01-01

    This study builds upon existing socio-cultural work into sports coaching by probing the meanings and varieties of the shared coach-athlete experience. Specifically, the paper utilises an autoethnographic approach in an attempt to chart the complex and dynamic relationship that existed between me, the principal author, as a rowing coxswain and my…

  5. Personality Characteristics of Death-row Prison Inmates

    ERIC Educational Resources Information Center

    Panton, James H.

    1976-01-01

    Attempts to understand the behavioral characteristics of Death Row inmates in order to provide an additional base for the shaping of treatments programs designed to meet the needs of inmates who are facing confinement and the prospect of death within a highly structured and controlled environment. (Author/RK)

  6. Personality characteristics of death-row prison inmates.

    PubMed

    Panton, J H

    1976-04-01

    An analysis of MMPI differences that appeared between a sample of 34 male inmates sentenced to be executed by asphyxiation and a representative prison population sample of 2,551 male inmates revealed that the profiles of both groups were indicative of a behavior disorder. The Death Row inmates presented significantly higher elevations on the PA and SC scales. Further evaluation of the subscale scores for the PA and SC scales demonstrated that the test responses of the Death Row inmates to these two scales were related more closely to feelings of resentment, hopelessness, failure, frustration, isolation and social alienation rather than to any delusional, dissociative or bizarre thought processes. Evaluation of the Death Row inmates' responses to four additional MMPI scales supported the previously made contention that the primary concern was with indices of a behavior disorder associated with the situational stress of being confined on Death Row to await execution rather than with indices of psychotic-appearing thought processes. In light of these findings it is felt that high PA and SC profiles scored by inmates who are awaiting execution should be supported by other MMPI scale, subscale and additional scale configurations, as well as other clinical inferences, before psychosis-related diagnoses are made. PMID:1262497

  7. Virtual hybrid bronchoscopy using PET/CT data sets

    NASA Astrophysics Data System (ADS)

    Englmeier, Karl-Hans; Seemann, Marcus D.

    2007-03-01

    The aim of this study was to demonstrate the possibilities, advantages and limitations of virtual bronchoscopy using data sets from positron emission tomography (PET) and computed tomography (CT). Eight consecutive patients with lung cancer underwent PET/CT. PET was performed with F-18-labelled 2-[fluorine-18]-fluoro-2-deoxy-D: -glucose ((18)F-FDG). The tracheobronchial system was segmented with a volume-growing algorithm, using the CT data sets, and visualized with a shaded-surface rendering method. The primary tumours and the lymph node metastases were segmented for virtual CT-bronchoscopy using the CT data set and for virtual PET/CT-bronchoscopy using the PET/CT data set. Virtual CT-bronchoscopy using the low-dose or diagnostic CT facilitates the detection of anatomical/morphological structure changes of the tracheobronchial system. Virtual PET/CT-bronchoscopy was superior to virtual CT-bronchoscopy in the detection of lymph node metastases (P=0.001), because it uses the CT information and the molecular/metabolic information from PET. Virtual PET/CT-bronchoscopy with a transparent colour-coded shaded-surface rendering model is expected to improve the diagnostic accuracy of identification and characterization of malignancies, assessment of tumour staging, differentiation of viable tumour tissue from atelectases and scars, verification of infections, evaluation of therapeutic response and detection of an early stage of recurrence that is not detectable or is misjudged in comparison with virtual CT-bronchoscopy.

  8. Rowing Crew Coordination Dynamics at Increasing Stroke Rates

    PubMed Central

    2015-01-01

    In rowing, perfect synchronisation is important for optimal performance of a crew. Remarkably, a recent study on ergometers demonstrated that antiphase crew coordination might be mechanically more efficient by reducing the power lost to within-cycle velocity fluctuations of the boat. However, coupled oscillator dynamics predict the stability of the coordination to decrease with increasing stroke rate, which in case of antiphase may eventually yield breakdowns to in-phase. Therefore, this study examined the effects of increasing stroke rate on in- and antiphase crew coordination in rowing dyads. Eleven experienced dyads rowed on two mechanically coupled ergometers on slides, which allowed the ergometer system to move back and forth as one ‘boat’. The dyads performed a ramp trial in both in- and antiphase pattern, in which stroke rates gradually increased from 30 strokes per minute (spm) to as fast as possible in steps of 2 spm. Kinematics of rowers, handles and ergometers were captured. Two dyads showed a breakdown of antiphase into in-phase coordination at the first stroke rate of the ramp trial. The other nine dyads reached between 34–42 spm in antiphase but achieved higher rates in in-phase. As expected, the coordinative accuracy in antiphase was worse than in in-phase crew coordination, while, somewhat surprisingly, the coordinative variability did not differ between the patterns. Whereas crew coordination did not substantially deteriorate with increasing stroke rate, stroke rate did affect the velocity fluctuations of the ergometers: fluctuations were clearly larger in the in-phase pattern than in the antiphase pattern, and this difference significantly increased with stroke rate. Together, these results suggest that although antiphase rowing is less stable (i.e., less resistant to perturbation), potential on-water benefits of antiphase over in-phase rowing may actually increase with stroke rate. PMID:26185987

  9. Numerical study of heat transfer in two-row heat exchangers having extended fin surfaces

    SciTech Connect

    Sheui, T.W.H.; Tsai, S.F.; Chiang, T.P.

    1999-05-28

    This paper reports on a three-dimensional study of air through two-row cylinder tubes. The analysis is intended to present a comparison of numerical and experimental data to validate the laminar flow postulation. The current study explores the influence of four perforated fin surfaces on the pressure drop and heat transfer rate. To gain further insight into the three-dimensional vortical flow structure, the authors conduct a topological study of the velocity field. Examination of the surface flow topology and the flow patterns at cross-flow plumes sheds some light on the complex interaction of the cylinder tube with the mainstream flow. This study clearly reveals a saddle point in front of the first row of cylinder tubes. Also clearly revealed by the computed solutions is a flow reversal found in the wake of the tube. The character of the critical-point-induced flow is also addressed. This study shows that the addition of perforated fins is not without deficiency. There is, in fact, a trade-off between the benefit of having an improved heat transfer and the penalty of having an increased pressure drop.

  10. Benchmarking a novel ultrasound-CT fusion system for respiratory motion management in radiotherapy: Assessment of spatio-temporal characteristics and comparison to 4DCT

    SciTech Connect

    Molloy, J. A.; Oldham, S. A.

    2008-01-15

    Management of respiratory motion during radiation therapy requires treatment planning and simulation using imaging modalities that possess sufficient spatio-temporal accuracy and precision. An investigation into the use of a novel ultrasound (United States) imaging system for assessment of respiratory motion is presented, exploiting its good soft tissue contrast and temporal precision. The system dynamically superimposes the appropriate image plane sampled from a reference CT data set with the corresponding US B-mode image. An articulating arm is used for spatial registration. While the focus of the study was to quantify the system's ability to track respiratory motion, certain unique spatial calibration procedures were devised that render the software potentially valuable to the general research community. These include direct access to all transformation matrix elements and image scaling factors, a manual latency correction function, and a three-point spatial registration procedure that allows the system to be used in any room possessing a traditional radiotherapy laser localization system. Counter-intuitively, it was discovered that a manual procedure for calibrating certain transformation matrix elements produced superior accuracy to that of an algorithmic Levenberg-Marquardt optimization method. The absolute spatial accuracy was verified by comparing the physical locations of phantom test objects measured using the spatially registered US system, and using data from a 3DCT scan of the phantom as a reference. The spatial accuracy of the display superposition was also tested in a similar manner. The system's dynamic properties were then assessed using three methods. First, the overall system response time was studied using a programmable motion phantom. This included US video update, articulating arm update, CT data set resampling, and image display. The next investigation verified the system's ability to measure the range of motion of a moving anatomical test

  11. Comparison of the effect of simple and complex acquisition trajectories on the 2D SPR and 3D voxelized differences for dedicated breast CT imaging

    NASA Astrophysics Data System (ADS)

    Shah, Jainil P.; Mann, Steve D.; McKinley, Randolph L.; Tornai, Martin P.

    2014-03-01

    The 2D scatter-to-primary (SPR) ratios and 3D voxelized difference volumes were characterized for a cone beam breast CT scanner capable of arbitrary (non-traditional) 3D trajectories. The CT system uses a 30x30cm2 flat panel imager with 197 micron pixellation and a rotating tungsten anode x-ray source with 0.3mm focal spot, with an SID of 70cm. Data were acquired for two cylindrical phantoms (12.5cm and 15cm diameter) filled with three different combinations of water and methanol yielding a range of uniform densities. Projections were acquired with two acquisition trajectories: 1) simple-circular azimuthal orbit with fixed tilt; and 2) saddle orbit following a +/-15° sinusoidal trajectory around the object. Projection data were acquired in 2x2 binned mode. Projections were scatter corrected using a beam stop array method, and the 2D SPR was measured on the projections. The scatter corrected and uncorrected data were then reconstructed individually using an iterative ordered subsets convex algorithm, and the 3D difference volumes were calculated as the absolute difference between the two. Results indicate that the 2D SPR is ~7-15% higher on projections with greatest tilt for the saddle orbit, due to the longer x-ray path length through the volume, compared to the 0° tilt projections. Additionally, the 2D SPR increases with object diameter as well as density. The 3D voxelized difference volumes are an estimate of the scatter contribution to the reconstructed attenuation coefficients on a voxel level. They help visualize minor deficiencies and artifacts in the volumes due to correction methods.

  12. PET/CT Dose Planning for Volumetric Modulated Arc Radiation Therapy (VMAT) -Comparison with Conventional Approach in Advanced Prostate Cancer Patients.

    PubMed

    Kairemo, Kalevi; Rasulova, Nigora; Kiljunen, Timo; Partanen, Kaarina; Kangasmäki, Aki; Joensuu, Timo

    2015-01-01

    Molecular imaging is the only way of defining biological target volume (BTV) for externalbeam radiation therapy (EBRT) and may be used for advanced targeting in dose planning and dose painting. There are, however, no reports about the EBRT response when dose planning is based on BTV target definition in advanced prostate cancer. Clinical and biochemical results of two clinically equal group of patients with advanced prostate cancer patients were compared. Both groups were treated with volumetric modulated arc therapy (VMAT) based on target definition by PET/CT (1(st) group) or conventional imaging (2(nd) group). Biochemical relapse occurred in 16.6% (in 1 out of 6) of the patients in the first group and 50% (3 out of 6) patients in the second group during the follow up period. Clinical manifestation of disease occurred in 33% (2 out of 6) patients of the first group and in 5 out of 6 (83,3%) patients in the second one. 4 patients in the first group had no biochemical relapse and no clinical manifestation during the follow up period. The difference in the duration of progression free period was statistically significant between the groups (p<0.010) being in the first group 16.5±5.4 (10-24) months and 4.6±2.9 (2-10) months in the second one. Because patients with PET/CT based VMAT had lower incidence of biochemical relapse, less clinical manifestations and longer, statistically significant duration of progression free period as compared to patients treated with VMAT based on conventional imaging, our preliminary results suggest introducing BTV definition based on PET imaging for VMAT in the EBRT of prostate cancer. PMID:25882786

  13. Comparison of Tumor Volumes as Determined by Pathologic Examination and FDG-PET/CT Images of Non-Small-Cell Lung Cancer: A Pilot Study

    SciTech Connect

    Yu Jinming; Li Xinke; Xing Ligang; Mu Dianbin; Fu Zheng; Sun Xiaorong; Sun Xiangyu; Yang Guoren; Zhang Baijiang; Sun Xindong; Ling, C. Clifton

    2009-12-01

    Purpose: To determine the cut-off standardized uptake value (SUV) on {sup 18}F fluoro-2-deoxy-glucose (FDG) positron emission tomography/computed tomography (FDG-PET/CT) images that generates the best volumetric match to pathologic gross tumor volume (GTV{sub path}) for non-small-cell lung cancer (NSCLC). Methods and Materials: Fifteen patients with NSCLC who underwent FDG-PET/CT scans followed by lobectomy were enrolled. The surgical specimen was dissected into 5-7-mum sections at approximately 4-mm intervals and stained with hematoxylin and eosin. The tumor-containing area was outlined slice by slice and the GTV{sub path} determined by summing over all the slices, taking into account the interslice thickness and fixation-induced volume reduction. The gross tumor volume from the PET images, GTV{sub PET}, was determined as a function of cut-off SUV. The optimal threshold or optimal absolute SUV was defined as the value at which the GTV{sub PET} was the same as the GTV{sub path}. Results: The fixation process induced a volumetric reduction to 82% +- 10% (range, 62-100%) of the original. The maximal SUV was 10.1 +- 3.6 (range, 4.2-18.7). The optimal threshold and absolute SUV were 31% +- 11% and 3.0 +- 1.6, respectively. The optimal threshold was inversely correlated with GTV{sub path} and tumor diameter (p < 0.05), but the optimal absolute SUV had no significant correlation with GTV{sub path} or tumor diameter (p > 0.05). Conclusion: This study evaluated the use of GTV{sub path} as a criterion for determining the optimal cut-off SUV for NSCLC target volume delineation. Confirmatory studies including more cases are being performed.

  14. IMPaCT Back study protocol. Implementation of subgrouping for targeted treatment systems for low back pain patients in primary care: a prospective population-based sequential comparison

    PubMed Central

    2010-01-01

    Background Prognostic assessment tools to identify subgroups of patients at risk of persistent low back pain who may benefit from targeted treatments have been developed and validated in primary care. The IMPaCT Back study is investigating the effects of introducing and supporting a subgrouping for targeted treatment system in primary care. Methods/Design A prospective, population-based, quality improvement study in one Primary Care Trust in England with a before and after design. Phases 1 and 3 collect data on current practice, attitudes and behaviour of health care practitioners, patients' outcomes and health care costs. Phase 2 introduces and supports the subgrouping for targeted treatment system, via a multi-component, quality improvement intervention that includes educational courses and outreach visits led by opinion leaders, audit/feedback, mentoring and organisational support to embed the subgrouping tools within IT and clinical management systems. We aim to recruit 1000 low back pain patients aged 18 years and over consulting 7 GP practices within one Primary Care Trust in England, UK. The study includes GPs in participating practices and physiotherapists in associated services. The primary objective is to determine the effect of the subgrouping for targeted treatment system on back pain related disability and catastrophising at 2 and 6 months, comparing data from phase 1 with phase 3. Key secondary objectives are to determine the impact on: a) GPs' and physiotherapists' attitudes and behaviour regarding low back pain; b) The process of care that patients receive; c) The cost-effectiveness and sustainability of the new clinical system. Discussion This paper details the rationale, design, methods, planned analysis and operational aspects of the IMPaCT Back study. We aim to determine whether the new subgrouping for targeted treatment system is implemented and sustained in primary care, and evaluate its impact on clinical decision-making, patient outcomes and

  15. Optimal cutoff threshold for calcium quantification in isotropic CT calcium scans by validating against registered intravascular ultrasound with radiofrequency backscatter.

    PubMed

    Dhungel, Abinashi; Qian, Zhen; Vazquez, Gustavo; Rinehart, Sarah; Weeks, Michael; Voros, Szilard

    2012-01-01

    3D Computed Tomography (CT) provides noninvasive, low-radiation method of coronary artery calcium (CAC) measurement. Conventional CAC images are acquired on multidetector-row CT scanners without contrast, and reconstructed with 3 mm slice thickness. The calcium volume is quantified by registering voxels with attenuation values greater than or equal to 130 Hounsfield Unit (HU). In isotropic CAC images with 0.5 mm slice thickness obtained from 320-detector row CT, the optimal value of attenuation cutoff threshold is unknown. In this paper we find the optimal cutoff threshold for calcium quantification in isotropic CT calcium scans by validating against registered intravascular ultrasound with radiofrequency backscatter (IVUS/VH). From the statistical analysis of calcium data obtained from the images of 9 patients we found a range of optimal thresholds and the conventional threshold of 130 HU was in the range. Further, the optimal values were different for individual patients. PMID:23367046

  16. Cultural practices to improve in-row weed control with cultivation in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivation is a proven effective means of weed control in organic peanut. However, weeds in-row often escape control. Research trials were conducted in Ty Ty, GA to modify cultural practices to help peanut suppress weed emergence in-row. Modified cultural practices were three row pattern/seeding...

  17. Row Spacing and Plant Population Effects on Cotton Produced With or Without Irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted from 2006 through 2008 to evaluate the effects of twin-row spacings, populations, and irrigation on cotton (Gossypium hirsutum L.) lint yields. Twin row systems, consisting of twin 18-, 25- and 38-cm rows on a 1-m bed at populations of 111,000 and 148,000 plants/acre, w...

  18. 33 CFR 100.724 - Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Rowing Regatta; Savannah River, Augusta, GA. 100.724 Section 100.724 Navigation and Navigable Waters... WATERS § 100.724 Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA. (a) Definitions... all non-participants. (2) After the termination of the Invitational Rowing Regatta each day,...

  19. 33 CFR 100.724 - Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Rowing Regatta; Savannah River, Augusta, GA. 100.724 Section 100.724 Navigation and Navigable Waters... WATERS § 100.724 Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA. (a) Definitions... all non-participants. (2) After the termination of the Invitational Rowing Regatta each day,...

  20. Row replacement is ineffective as a cultural control practice for Meloidogyne incognita in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine if planting cotton into the space between the previous year's rows reduces crop loss due to nematodes compared to planting in the same row every year. In 2004, nematode counts were lower in plots planted in the previous year’s rows on 4 Aug (P = 0.064) a...

  1. Row-Sum of a Class of M-Bonomial Coefficients

    ERIC Educational Resources Information Center

    Asiru, Muniru A.

    2011-01-01

    Formulae for row-sum of M-bonomial coefficients [image omitted] where G is an mth g-gonal number is developed from a study of the ratio between consecutive terms of the sequence of row-sum. The result generalizes the formula for row-sum of binomial coefficients: [image omitted].

  2. Alternate row placement is ineffective for cultural control of Meloidogyne incognita in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine if planting cotton into the space between the previous year's rows reduces crop loss due to nematodes compared to planting in the same row every year. Row placement had a significant (P = 0.05) effect on nematode counts only on 8 July 2005. Plots receiv...

  3. 7 CFR 810.205 - Grades and grade requirements for Two-rowed Malting barley.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Grades and grade requirements for Two-rowed Malting... the Application of Standards § 810.205 Grades and grade requirements for Two-rowed Malting barley... shall not contain any special grades as defined in § 810.206. Two-rowed Malting barley varieties...

  4. 77 FR 25073 - Special Local Regulation; Hebda Cup Rowing Regatta, Trenton Channel; Detroit River, Wyandotte, MI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... SECURITY Coast Guard 33 CFR Part 100 RIN 1625-AA08 Special Local Regulation; Hebda Cup Rowing Regatta... on the navigable waters immediately prior to, during, and immediately after the Hebda Cup Rowing... Purpose On April 28, 2012, the Wyandotte Boat Club is holding a rowing race that will require...

  5. 33 CFR 100.724 - Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Rowing Regatta; Savannah River, Augusta, GA. 100.724 Section 100.724 Navigation and Navigable Waters... WATERS § 100.724 Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA. (a) Definitions... all non-participants. (2) After the termination of the Invitational Rowing Regatta each day,...

  6. Sunflower Production in Skip Row Configurations for the Semi-Arid Central Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sunflower production in the semi-arid Central Great Plains is usually limited by precipitation. In skip-row planting configurations, one or more rows are omitted in between planted rows), possibly allowing roots to grow into moisture throughout the growing season, thus leaving water available for gr...

  7. Growth and yield of valencia, spanish, virginia and runner market type peanuts in various row spacings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently, the majority of peanuts grown in New Mexico and West Texas are planted in single rows on beds 36 to 40 inches apart. In 2006-2008, several field studies were conducted with Valencia peanuts comparing single row, twin row, and diamond planting patterns in various populations. The basic c...

  8. Computed Tomography (CT) - Spine

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Spine Computed tomography (CT) of the spine is a diagnostic imaging ... Spine? What is CT Scanning of the Spine? Computed tomography, more commonly known as a CT or CAT ...

  9. Comparison between CT-based volumetric calculations and ICRU reference-point estimates of radiation doses delivered to bladder and rectum during intracavitary radiotherapy for cervical cancer

    SciTech Connect

    Pelloski, Christopher E.; Palmer, Matthew B.S.; Chronowski, Gregory M.; Jhingran, Anuja; Horton, John; Eifel, Patricia J. . E-mail: peifel@mdanderson.org

    2005-05-01

    Purpose: To compare CT-based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the uterine cervix treated with definitive low-dose-rate intracavitary radiotherapy (ICRT). Methods and Materials: Between November 2001 and March 2003, 60 patients were prospectively enrolled in a pilot study of ICRT with CT-based dosimetry. Most patients underwent two ICRT insertions. After insertion of an afterloading ICRT applicator, intraoperative orthogonal films were obtained to ensure proper positioning of the system and to facilitate subsequent planning. Treatments were prescribed using standard two-dimensional dosimetry and planning. Patients also underwent helical CT of the pelvis for three-dimensional reconstruction of the radiation dose distributions. The systems were loaded with {sup 137}Cs sources using the Selectron remote afterloading system according to institutional practice for low-dose-rate brachytherapy. Three-dimensional dose distributions were generated using the Varian BrachyVision treatment planning system. The rectum was contoured from the bottom of the ischial tuberosities to the sigmoid flexure. The entire bladder was contoured. The minimal doses delivered to the 2 cm{sup 3} of bladder and rectum receiving the highest dose (D{sub BV2} and D{sub RV2}, respectively) were determined from dose-volume histograms, and these estimates were compared with two-dimensionally derived estimates of the doses to the corresponding ICRU reference points. Results: A total of 118 unique intracavitary insertions were performed, and 93 were evaluated and the subject of this analysis. For the rectum, the estimated doses to the ICRU reference point did not differ significantly from the D{sub RV2} (p = 0.561); the mean ({+-} standard deviation) difference was 21 cGy ({+-} 344 cGy). The median volume of the rectum that received at least

  10. Repositioning accuracy of two different mask systems-3D revisited: Comparison using true 3D/3D matching with cone-beam CT

    SciTech Connect

    Boda-Heggemann, Judit . E-mail: judit.boda-heggemann@radonk.ma.uni-heidelberg.de; Walter, Cornelia; Rahn, Angelika; Wertz, Hansjoerg; Loeb, Iris; Lohr, Frank; Wenz, Frederik

    2006-12-01

    Purpose: The repositioning accuracy of mask-based fixation systems has been assessed with two-dimensional/two-dimensional or two-dimensional/three-dimensional (3D) matching. We analyzed the accuracy of commercially available head mask systems, using true 3D/3D matching, with X-ray volume imaging and cone-beam CT. Methods and Materials: Twenty-one patients receiving radiotherapy (intracranial/head-and-neck tumors) were evaluated (14 patients with rigid and 7 with thermoplastic masks). X-ray volume imaging was analyzed online and offline separately for the skull and neck regions. Translation/rotation errors of the target isocenter were analyzed. Four patients were treated to neck sites. For these patients, repositioning was aided by additional body tattoos. A separate analysis of the setup error on the basis of the registration of the cervical vertebra was performed. The residual error after correction and intrafractional motility were calculated. Results: The mean length of the displacement vector for rigid masks was 0.312 {+-} 0.152 cm (intracranial) and 0.586 {+-} 0.294 cm (neck). For the thermoplastic masks, the value was 0.472 {+-} 0.174 cm (intracranial) and 0.726 {+-} 0.445 cm (neck). Rigid masks with body tattoos had a displacement vector length in the neck region of 0.35 {+-} 0.197 cm. The intracranial residual error and intrafractional motility after X-ray volume imaging correction for rigid masks was 0.188 {+-} 0.074 cm, and was 0.134 {+-} 0.14 cm for thermoplastic masks. Conclusions: The results of our study have demonstrated that rigid masks have a high intracranial repositioning accuracy per se. Given the small residual error and intrafractional movement, thermoplastic masks may also be used for high-precision treatments when combined with cone-beam CT. The neck region repositioning accuracy was worse than the intracranial accuracy in both cases. However, body tattoos and image guidance improved the accuracy. Finally, the combination of both mask

  11. Prospective Evaluation of Prior Image Constrained Compressed Sensing (PICCS) Algorithm in Abdominal CT: A comparison of reduced dose with standard dose imaging

    PubMed Central

    Lubner, Meghan G.; Pickhardt, Perry J.; Kim, David H.; Tang, Jie; Munoz del Rio, Alejandro; Chen, Guang-Hong

    2014-01-01

    Purpose To prospectively study CT dose reduction using the “prior image constrained compressed sensing” (PICCS) reconstruction technique. Methods Immediately following routine standard dose (SD) abdominal MDCT, 50 patients (mean age, 57.7 years; mean BMI, 28.8) underwent a second reduced-dose (RD) scan (targeted dose reduction, 70-90%). DLP, CTDIvol and SSDE were compared. Several reconstruction algorithms (FBP, ASIR, and PICCS) were applied to the RD series. SD images with FBP served as reference standard. Two blinded readers evaluated each series for subjective image quality and focal lesion detection. Results Mean DLP, CTDIvol, and SSDE for RD series was 140.3 mGy*cm (median 79.4), 3.7 mGy (median 1.8), and 4.2 mGy (median 2.3) compared with 493.7 mGy*cm (median 345.8), 12.9 mGy (median 7.9 mGy) and 14.6 mGy (median 10.1) for SD series, respectively. Mean effective patient diameter was 30.1 cm (median 30), which translates to a mean SSDE reduction of 72% (p<0.001). RD-PICCS image quality score was 2.8±0.5, improved over the RD-FBP (1.7±0.7) and RD-ASIR(1.9±0.8)(p<0.001), but lower than SD (3.5±0.5)(p<0.001). Readers detected 81% (184/228) of focal lesions on RD-PICCS series, versus 67% (153/228) and 65% (149/228) for RD-FBP and RD-ASIR, respectively. Mean image noise was significantly reduced on RD-PICCS series (13.9 HU) compared with RD-FBP (57.2) and RD-ASIR (44.1) (p<0.001). Conclusion PICCS allows for marked dose reduction at abdominal CT with improved image quality and diagnostic performance over reduced-dose FBP and ASIR. Further study is needed to determine indication-specific dose reduction levels that preserve acceptable diagnostic accuracy relative to higher-dose protocols. PMID:24943136

  12. High-pitch coronary CT angiography at 70 kVp with low contrast medium volume: comparison of 80 and 100 kVp high-pitch protocols.

    PubMed

    Zhang, Long Jiang; Qi, Li; De Cecco, Carlo N; Zhou, Chang Sheng; Spearman, James V; Schoepf, U Joseph; Lu, Guang Ming

    2014-11-01

    The purpose of this article is to evaluate image quality and radiation dose of prospectively electrocardiogram (ECG)-triggered high-pitch coronary computed tomography angiography (CCTA) at 70 kVp and 30 mL contrast medium.One hundred fifty patients with a heart rate ≤70 beats per minute (bpm) underwent CCTA using a second-generation dual-source computed tomography (CT) scanner and were randomized into 3 groups according to tube voltage and contrast medium volume (370 mg/mL iodine concentration) (100 kVp group, 100 kVp/60 mL, n = 55; 80 kVp group, 80 kVp/60 mL, n = 44; 70 kVp group, 70 kVp/30 mL, n = 51). Objective and subjective image quality along with the effect of heart rate (HR) and body mass index (BMI) was evaluated and compared between the groups. Radiation dose was estimated for each patient.CT attenuation and image noise were higher in the 80 and 70 kVp groups than in the 100 kVp group (all P < 0.001). Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were lower in the 70 kVp group than in the 80 and 100 kVp groups (all P < 0.05). There was no difference for subjective image quality between the groups (P > 0.05). HR did not affect subjective image quality (all P > 0.05), while patients with BMI <23 kg/m had higher image quality than patients with BMI ≥23 kg/m (P < 0.05). Compared with the 100 kVp group, the radiation dose of the 70 kVp group was reduced by 75%.In conclusion, prospectively ECG-triggered high-pitch 70 kVp/30 mL CCTA can obtain diagnostic image quality with lower radiation dose in selected patients with BMI <23 kg/m compared with 80/100 kVp/60 mL CCTA. PMID:25396334

  13. Pressure loss and heat transfer through multiple rows of short pin fins

    NASA Astrophysics Data System (ADS)

    Metzger, D. E.; Fan, Z. X.; Shepard, W. B.

    Results are presented showing performance in terms of pressure loss and heat transfer for arrays of short pin fins set in a high aspect ratio duct. Seven array configurations were fabricated and tested, typical of those used for heat transfer augmentation in gas turbine airfoil cooling. All configurations have uniform regular pin spacing with alternate rows in the streamwise direction staggered one-half the transverse pitch. The short length of the pins dictates that the uncovered duct walls are a significant fraction of the total heat transfer area. Comparison is made between the present short pin results and established tube bank performance where the tube surfaces account for all the heat transfer area.

  14. Mental competence and end-of-life decision making: death row volunteering and euthanasia.

    PubMed

    Harrington, C Lee

    2004-12-01

    This article reports on a qualitative study of defense attorneys' perceptions of the mental competence or rationality of death row inmates' decisions to waive habeas appeals and proceed directly to execution. Interviews were conducted with twenty attorneys who have either directly represented or been closely involved with would-be volunteers. Through analytic comparison with another end-of-life decision, euthanasia, this article reports on four themes from the interviews: (a) attorneys' perceptions of the legal standard of competence, (b) their perceptions of the competency evaluation process, (c) implications of competing interpretive frames (i.e., volunteering vs. suicide), and (d) the rationality of decisions to waive appeals. Implications of research findings, particularly in terms of recent restructured models of competence, are also discussed. PMID:15688579

  15. Computation of three-dimensional, rotational flow through turbomachinery blade rows for improved aerodynamic design studies

    NASA Technical Reports Server (NTRS)

    Subramanian, S. V.; Bozzola, R.; Povinelli, L. A.

    1986-01-01

    The performance of a three dimensional computer code developed for predicting the flowfield in stationary and rotating turbomachinery blade rows is described in this study. The four stage Runge-Kutta numerical integration scheme is used for solving the governing flow equations and yields solution to the full, three dimensional, unsteady Euler equations in cylindrical coordinates. This method is fully explicit and uses the finite volume, time marching procedure. In order to demonstrate the accuracy and efficiency of the code, steady solutions were obtained for several cascade geometries under widely varying flow conditions. Computed flowfield results are presented for a fully subsonic turbine stator and a low aspect ratio, transonic compressor rotor blade under maximum flow and peak efficiency design conditions. Comparisons with Laser Anemometer measurements and other numerical predictions are also provided to illustrate that the present method predicts important flow features with good accuracy and can be used for cost effective aerodynamic design studies.

  16. ProTaper and WaveOne systems three-dimensional comparison of device parameters after the shaping technique. A micro-CT study on simulated root canals

    PubMed Central

    Dioguardi, Mario; Troiano, Giuseppe; Laino, Luigi; Russo, Lucio Lo; Giannatempo, Giovanni; Lauritano, Floriana; Cicciù, Marco; Muzio, Lorenzo Lo

    2015-01-01

    Aim: The aim of this study is to highlights possible differences in the volume of shaping and canal surface area after the using of common endodontic devices ProTaper Universal and WaveOne systems. Methods: Forty ISO 15, 0.02 taper, S-shaped endo-training Blocks (Dentsply, Maillefer) were assigned in two groups (n = 20 for each group). For each block the initial working length (WL) was evaluated with a 10 K-files (Dentsply Maillefer), so the glide path was created with PathFile 1, 2 and 3 (Dentsply Maillefer) at the WL. After that, simulated canals in the group 1 were shaped with S1, S2, F1 and F2 at WL; while in group 2 it was used single-file WaveOne primary in reciprocating motion. After shaping, the resin blocks were analysed with Skyscan 1172 scanner (Skyscan, Kontich, Belgium) and then volumetrically at a source voltage of 65 kV and a source current of 153 uA. Results: No statistically differences (P > 0.05) have been found in terms of volume and surface area after the use of ProTaper Universal and WaveOne systems. Conclusions: Although, results from micro-CT analysis revealed that Wave One result in a decrease of volume and surface area of shaping than ProTaper Universal, differences are not statistically significant. PMID:26770376

  17. COMPARISON OF ADAPTIVE STATISTICAL ITERATIVE RECONSTRUCTION (ASIR™) AND MODEL-BASED ITERATIVE RECONSTRUCTION (VEO™) FOR PAEDIATRIC ABDOMINAL CT EXAMINATIONS: AN OBSERVER PERFORMANCE STUDY OF DIAGNOSTIC IMAGE QUALITY.

    PubMed

    Hultenmo, Maria; Caisander, Håkan; Mack, Karsten; Thilander-Klang, Anne

    2016-06-01

    The diagnostic image quality of 75 paediatric abdominal computed tomography (CT) examinations reconstructed with two different iterative reconstruction (IR) algorithms-adaptive statistical IR (ASiR™) and model-based IR (Veo™)-was compared. Axial and coronal images were reconstructed with 70 % ASiR with the Soft™ convolution kernel and with the Veo algorithm. The thickness of the reconstructed images was 2.5 or 5 mm depending on the scanning protocol used. Four radiologists graded the delineation of six abdominal structures and the diagnostic usefulness of the image quality. The Veo reconstruction significantly improved the visibility of most of the structures compared with ASiR in all subgroups of images. For coronal images, the Veo reconstruction resulted in significantly improved ratings of the diagnostic use of the image quality compared with the ASiR reconstruction. This was not seen for the axial images. The greatest improvement using Veo reconstruction was observed for the 2.5 mm coronal slices. PMID:26873711

  18. High Energy-Efficiency Retrofits to Baltimore's Row Homes

    SciTech Connect

    Chalk, J.; Johnson, A.L.; Lipscomb, L.; Wendt, R.

    1999-04-19

    The purpose of the research project is to develop high-perfommnce, energy-eflicient retrofits of existing row homes in Baltimore, Maryland. These efficiency enhancements are to optimize building envelope improvements, mechanical equipment improvements and operational improvements to the highest cost-effective level. Furthermore, this project is to investigate and demonstrate the impact of high-performance energy-efficiency retrofit improvements on row homes in the Historic East area of Baltimore. Three homes awaiting renovation are planned to receive building envelope, mechanical system, and electrical system improvements that will improve their energy petiormance. An incremental additional cost ceiling of $4000 for the energy eftlciency improvements, beyond those normally installed, has been set by the project.

  19. Optimisation of the mean boat velocity in rowing.

    PubMed

    Rauter, G; Baumgartner, L; Denoth, J; Riener, R; Wolf, P

    2012-01-01

    In rowing, motor learning may be facilitated by augmented feedback that displays the ratio between actual mean boat velocity and maximal achievable mean boat velocity. To provide this ratio, the aim of this work was to develop and evaluate an algorithm calculating an individual maximal mean boat velocity. The algorithm optimised the horizontal oar movement under constraints such as the individual range of the horizontal oar displacement, individual timing of catch and release and an individual power-angle relation. Immersion and turning of the oar were simplified, and the seat movement of a professional rower was implemented. The feasibility of the algorithm, and of the associated ratio between actual boat velocity and optimised boat velocity, was confirmed by a study on four subjects: as expected, advanced rowing skills resulted in higher ratios, and the maximal mean boat velocity depended on the range of the horizontal oar displacement. PMID:21491254

  20. Monitoring and evaluation of rowing performance using mobile mapping data

    NASA Astrophysics Data System (ADS)

    Mpimis, A.; Gikas, V.

    2011-12-01

    Traditionally, the term mobile mapping refers to a means of collecting geospatial data using mapping sensors that are mounted on a mobile platform. Historically, this process was mainly driven by the need for highway infrastructure mapping and transportation corridor inventories. However, the recent advances in mapping sensor and telecommunication technologies create the opportunity that, completely new, emergent application areas of mobile mapping to evolve rapidly. This article examines the potential of mobile mapping technology (MMT) in sports science and in particular in competitive rowing. Notably, in this study the concept definition of mobile mapping somehow differs from the traditional one in a way that, the end result is not relevant to the geospatial information acquired as the moving platform travels in space. In contrast, the interest is placed on the moving platform (rowing boat) itself and on the various subsystems which are also in continuous motion.

  1. Augmentation of heat transfer by longitudinal vortices in plate-fin heat exchangers with two rows of tubes

    SciTech Connect

    Rodrigues, R. Jr.; Yanagihara, J.I.

    1999-07-01

    The thermal performance of fin-tube compact heat exchangers is highly affected by the thermal resistance occurring on the air side, which is much higher than the thermal resistance inside the tubes. Since this kind of heat exchanger is widely used in these days, with applications on air-conditioning, refrigeration, automobilistic industry and many other areas, the development of more efficient and cheaper heat exchangers is highly attractive, because it will permit the manufacturing of more competitive equipments. This work presents results of numerical simulations for fin-tube compact heat exchangers using smooth fins and longitudinal vortex generators. The computational model has two rows of round tubes in staggered arrangement. Built-in delta winglet vortex generators were used, and its geometric dimensions were chosen according to the best results of literature. The steady-state numerical simulations were carried out at Re = 300, with a code based on the finite volume method. The typical configuration, where the vortex generators of both tube rows have identical parameters set, was compared with new ones where the vortex generators of the second row have different attack angles and positions. The global and local influence of vortex generators on heat transfer and flow losses are analyzed by comparison with a smooth fin model without vortex generators. The results show that a best heat transfer performance can be obtained by positioning the vortex generators of the second row at a particular position and angle of attack, when the increasing of the flow losses was smaller than the heat transfer enhancement achieved.

  2. Three-Dimensional Turbomachine-Blade-Row Analysis Code

    NASA Technical Reports Server (NTRS)

    Glassman, A. J.; Wood, J. R.

    1986-01-01

    Computer program (MERNEW3D) developed that prepares bulk of input data set required for Denton three-dimensional inviscid turbomachine-blade-row analysis code. Denton input generated from minimum of geometry and flow-variable information by using cubic spline curve fits for interpolation and extrapolation. Curve-fitting procedures taken from previously developed and widely used NASA computer program (MERIDL), which performs meridional streamsurface analysis.

  3. Acquiring 4D Thoracic CT Scans Using Ciné CT Acquisition

    NASA Astrophysics Data System (ADS)

    Low, Daniel

    One method for acquiring 4D thoracic CT scans is to use ciné acquisition. Ciné acquisition is conducted by rotating the gantry and acquiring x-ray projections while keeping the couch stationary. After a complete rotation, a single set of CT slices, the number corresponding to the number of CT detector rows, is produced. The rotation period is typically sub second so each image set corresponds to a single point in time. The ciné image acquisition is repeated for at least one breathing cycle to acquire images throughout the breathing cycle. Once the images are acquired at a single couch position, the couch is moved to the abutting position and the acquisition is repeated. Post-processing of the images sets typically resorts the sets into breathing phases, stacking images from a specific phase to produce a thoracic CT scan at that phase. Benefits of the ciné acquisition protocol include, the ability to precisely identify the phase with respect to the acquired image, the ability to resort images after reconstruction, and the ability to acquire images over arbitrarily long times and for arbitrarily many images (within dose constraints).

  4. A review of turbomachinery blade-row interaction research

    NASA Technical Reports Server (NTRS)

    Smith, Todd E.

    1988-01-01

    Analytical and experimental research in the area of unsteady aerodynamics of turbomachinery has conventionally been applied to blading which oscillates when placed in a uniformly flowing fluid. Comparatively less effort has been offered for the study of blading which is subjected to nonuniformities within the flow field. The fluid dynamic environment of a blade-row embedded within multi-stage turbomachines is dominated by such highly unsteady fluid flow conditions. The production of wakes and circumferential pressure variations from adjacent blade-rows causes large unsteady energy transfers between the fluid and the blades. Determination of the forced response of a blade requires the ability to predict the unsteady loads which are induced by these aerodynamic sources. A review of research publications was done to determine recent investigations of the response of turbomachinery blading subjected to aerodynamic excitations. Such excitations are a direct result of the blade-row aerodynamic interaction which occurs between adjacent cascades of blades. The reports and papers reviewed have been organized into areas emphasizing experimental or analytical efforts.

  5. The effect of including a series of isometric conditioning contractions to the rowing warm-up on 1,000-m rowing ergometer time trial performance.

    PubMed

    Feros, Simon A; Young, Warren B; Rice, Anthony J; Talpey, Scott W

    2012-12-01

    Rowing requires strength, power, and strength-endurance for optimal performance. A rowing-based warm-up could be enhanced by exploiting the postactivation potentiation (PAP) phenomenon, acutely enhancing power output at the beginning of a race where it is needed most. Minimal research has investigated the effects of PAP on events of longer duration (i.e. 1,000-m rowing). The purpose of this research was to investigate the effects of PAP on 1,000-m rowing ergometer performance through the use of 2 different warm-up procedures: (a) a rowing warm-up combined with a series of isometric conditioning contractions, known as the potentiated warm-up (PW), and (b) a rowing warm-up only (NW). The isometric conditioning contractions in the PW were performed by "pulling" an immovable handle on the rowing ergometer, consisting of 5 sets of 5 seconds (2 seconds at submaximal intensity, and 3 seconds at maximal intensity), with a 15-second recovery between sets. The 1,000-m rowing ergometer time trial was performed after each warm-up condition, whereby mean power output, mean stroke rate, and split time were assessed every 100 m. Ten Australian national level rowers served as the subjects and performed both conditions in a counterbalanced order on separate days. The PW reduced 1,000-m time by 0.8% (p > 0.05). The PW improved mean power output by 6.6% (p < 0.01) and mean stroke rate by 5.2% (p < 0.01) over the first 500 m; resulting in a reduction of 500-m time by 1.9% (p < 0.01), compared with the NW. It appears that the inclusion of isometric conditioning contractions to the rowing warm-up enhance short-term rowing ergometer performance (especially at the start of a race) to a greater extent than a rowing warm-up alone. PMID:22266645

  6. Evaluation of the cone beam CT for internal target volume localization in lung stereotactic radiotherapy in comparison with 4D MIP images

    SciTech Connect

    Wang, Lu; Chen, Xiaoming; Lin, Mu-Han; Lin, Teh; Fan, Jiajin; Jin, Lihui; Ma, Charlie M.; Xue, Jun

    2013-11-15

    Purpose: To investigate whether the three-dimensional cone-beam CT (CBCT) is clinically equivalent to the four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) reconstructed images for internal target volume (ITV) localization in image-guided lung stereotactic radiotherapy.Methods: A ball-shaped polystyrene phantom with built-in cube, sphere, and cone of known volumes was attached to a motor-driven platform, which simulates a sinusoidal movement with changeable motion amplitude and frequency. Target motion was simulated in the patient in a superior-inferior (S-I) direction with three motion periods and 2 cm peak-to-peak amplitudes. The Varian onboard Exact-Arms kV CBCT system and the GE LightSpeed four-slice CT integrated with the respiratory-position-management 4DCT scanner were used to scan the moving phantom. MIP images were generated from the 4DCT images. The clinical equivalence of the two sets of images was evaluated by comparing the extreme locations of the moving objects along the motion direction, the centroid position of the ITV, and the ITV volumes that were contoured automatically by Velocity or calculated with an imaging gradient method. The authors compared the ITV volumes determined by the above methods with those theoretically predicted by taking into account the physical object dimensions and the motion amplitudes. The extreme locations were determined by the gradient method along the S-I axis through the center of the object. The centroid positions were determined by autocenter functions. The effect of motion period on the volume sizes was also studied.Results: It was found that the extreme locations of the objects determined from the two image modalities agreed with each other satisfactorily. They were not affected by the motion period. The average difference between the two modalities in the extreme locations was 0.68% for the cube, 1.35% for the sphere, and 0.5% for the cone, respectively. The maximum difference in the

  7. Radical Prostatectomy versus External Beam Radiotherapy for cT1-4N0M0 Prostate Cancer: Comparison of Patient Outcomes Including Mortality

    PubMed Central

    Taguchi, Satoru; Fukuhara, Hiroshi; Shiraishi, Kenshiro; Nakagawa, Keiichi; Morikawa, Teppei; Kakutani, Shigenori; Takeshima, Yuta; Miyazaki, Hideyo; Fujimura, Tetsuya; Nakagawa, Tohru; Kume, Haruki; Homma, Yukio

    2015-01-01

    Background Although radical prostatectomy (RP) and external beam radiotherapy (EBRT) have been considered as comparable treatments for localized prostate cancer (PC), it is controversial which treatment is better. The present study aimed to compare outcomes, including mortality, of RP and EBRT for localized PC. Methods We retrospectively analyzed 891 patients with cT1-4N0M0 PC who underwent either RP (n = 569) or EBRT (n = 322) with curative intent at our single institution between 2005 and 2012. Of the EBRT patients, 302 (93.8%) underwent intensity-modulated radiotherapy. Primary endpoints were overall survival (OS) and cancer-specific survival (CSS). Related to these, other-cause mortality (OCM) was also calculated. Biochemical recurrence-free survival was assessed as a secondary endpoint. Cox proportional hazards model was used for multivariate analysis. Results Median follow-up durations were 53 and 45 months, and median ages were 66 and 70 years (P <0.0001), in the RP and EBRT groups, respectively. As a whole, significantly better prognoses of the RP group than the EBRT group were observed for both OS and CSS, although OCM was significantly higher in the EBRT group. There was no death from PC in men with low and intermediate D’Amico risks, except one with intermediate-risk in the EBRT group. In high-risk patients, significantly more patients died from PC in the EBRT group than the RP group. Multivariate analysis demonstrated the RP group to be an independent prognostic factor for better CSS. On the other hand, the EBRT group had a significantly longer biochemical recurrence-free survival than the RP group. Conclusions Mortality outcomes of both RP and EBRT were generally favorable in low and intermediate risk patients. Improvement of CSS in high risk patients was seen in patients receiving RP over those receiving EBRT. PMID:26506569

  8. CT angiography of neonates and infants: comparison of radiation dose and image quality of target mode prospectively ECG-gated 320-MDCT and ungated helical 64-MDCT.

    PubMed

    Jadhav, Siddharth P; Golriz, Farahnaz; Atweh, Lamya A; Zhang, Wei; Krishnamurthy, Rajesh

    2015-02-01

    OBJECTIVE. The purpose of this study was to evaluate the radiation dose and image quality of target mode prospectively ECG-gated volumetric CT angiography (CTA) performed with a 320-MDCT scanner compared with the radiation dose and image quality of ungated helical CTA performed with a 64-MDCT scanner. MATERIALS AND METHODS. An experience with CTA for cardiovascular indications in neonates and infants 0-6 months old was retrospectively assessed. Radiation doses and quantitative and qualitative image quality scores of 28 CTA examinations performed with a 320-MDCT scanner and volumetric target mode prospective ECG gating plus iterative reconstruction (target mode) were compared with the doses and scores of 28 CTA examinations performed with a 64-MDCT scanner and ungated helical scanning plus filtered back projection reconstruction (ungated mode). All target mode studies were performed during free breathing. Seven ungated CTA examinations (25%) were performed with general endotracheal anesthesia. The findings of 17 preoperative CTA examinations performed in target mode were also compared with surgical reports for evaluation of diagnostic accuracy. RESULTS. All studies performed with target mode technique were diagnostic for the main clinical indication. Effective doses were significantly lower in the target mode group (0.51 ± 0.19 mSv) compared with the ungated mode group (4.8 ± 1.4 mSv) (p < 0.0001). Quantitative analysis revealed no statistically significant difference between the two groups with respect to signal-to-noise ratio (of pulmonary artery and aorta) and contrast-to-noise ratio. Subjective image quality was significantly better with target mode than with ungated mode (p < 0.0001). CONCLUSION. Target mode prospectively ECG-gated volumetric scanning with iterative reconstruction performed with a 320-MDCT scanner has several benefits in cardiovascular imaging of neonates and infants, including low radiation dose, improved image quality, high diagnostic

  9. Comparison of linear and angular measurements using two-dimensional conventional methods and three-dimensional cone beam CT images reconstructed from a volumetric rendering program in vivo

    PubMed Central

    Oz, U; Orhan, K; Abe, N

    2011-01-01

    Objective The aim of this study was to compare the linear and angular measurements made on two-dimensional (2D) conventional cephalometric images and three-dimensional (3D) cone beam CT (CBCT) generated cephalograms derived from a 3D volumetric rendering program. Methods Pre-treatment cephalometric digital radiographs of 11 patients and their corresponding CBCT images were randomly selected. The digital cephalometric radiographs were traced using Vista Dent OC (GAC International, Inc Bohemia, NY) and by hand. CBCT and Maxilim® (Medicim, Sint-Niklass, Belgium) software were used to generate cephalograms from the CBCT data set that were then linked to the 3D hard-tissue surface representations. In total, 16 cephalometric landmarks were identified and 18 widely used measurements (11 linear and 7 angular) were performed by 2 independent observers. Intraobserver reliability was assessed by calculating intraclass correlation coefficients (ICC), interobserver reliability was assessed with Student t-test and analysis of variance (ANOVA). Mann–Whitney U-tests and Kruskal–Wallis H tests were also used to compare the three methods (P < 0.05). Results The results demonstrated no statistically significant difference between interobserver analyses for CBCT-generated cephalograms (P < 0.05), except for Gonion-Menton (Go-Me) and Condylion-Gnathion (Co-Gn). Intraobserver examinations showed low ICCs, which was an indication of poor reproducibility for Go-Me and Sella-Nasion (S-N) in CBCT-generated cephalograms and poor reproducibility for Articulare-Gonion (Ar-Go) in the 2D hand tracing method (P < 0.05). No statistical significance was found for Vista Dent OC measurements (P > 0.05). Conclusions Measurements from in vivo CBCT-generated cephalograms from Maxilim® software were found to be similar to conventional images. Thus, owing to higher radiation exposure, CBCT examinations should only be used when the inherent 3D information could improve the outcome of treatment. PMID

  10. MULTIDETECTOR-ROW COMPUTED TOMOGRAPHIC CHARACTERISTICS OF PRESUMED PREURETERAL VENA CAVA IN CATS.

    PubMed

    Pey, Pascaline; Marcon, Oriana; Drigo, Michele; Specchi, Swan; Bertolini, Giovanna

    2015-01-01

    Preureteral vena cava (circumcaval ureter, retrocaval ureter) occurs in a third of the feline population and has been associated with ureteral strictures in humans. The aim of this retrospective cross-sectional study was to describe the contrast-enhanced multidetector row computed tomographic (MDCT) characteristics of presumed preureteral vena cava in a group of cats. Medical records from two institutions located in different continents were searched from 2010-2013 for cases with complete contrast-enhanced MDCT examinations of the abdomen (i.e. included the entire course of the ureters and prerenal and renal segments of the caudal vena cava) and a diagnosis of preureteral caudal vena cava. For cases meeting inclusion criteria, CT scan data were retrieved and characteristics of the preureteral caudal vena cava were recorded. Presence of concomitant renal or ureteral diseases was also recorded. A total of 272 cats had contrast-enhanced abdominal CT scans during the study period and of these, 68 cats (22.43 ± 4.96%) had a diagnosis of presumed preureteral vena cava. In all affected cats, a "reverse-J ureter" was observed, i.e. a ureter running medially at the level of L4-5, passing dorsally to the caudal vena cava and then exiting ventrally between the caudal vena cava and aorta returning to its normal position. Having a preureteral vena cava resulted in an increased risk for concurrent urinary signs (OR = 3.00; CI: 95%; 1.28-6.99; P = 0.01). Findings supported the use of contrast-enhanced MDCT for characterizing morphology of preureteral vena cava and its relation with ureters in cats. PMID:25786990

  11. Windmill artifact in multislice helical CT

    NASA Astrophysics Data System (ADS)

    Silver, Michael D.; Taguchi, Katsuyuki; Hein, Ilmar A.; Chiang, BeShan; Kazama, Masahiro; Mori, Issei

    2003-05-01

    Multi-slice helical CT-systems suffer from windmill artifacts: black/white patterns that spin off of features with high longitudinal gradients. The number of black/white pairs matches the number of slices (detector rows) in the multi-slive detector. The period of spin is the same as the helical pitch. We investigate the cause of the pattern by following the traces of selected voxels through the multi-slive detector array as a function of view position. This forms an "extracted sinogram" which represents the data used to reconstruct the specific voxel. Now we can determine the cause of the artifact by correlating the windmill streak in the image with the extracted data. The investigation shows that inadequate sampling along the longitudinal direction causes the artifact.

  12. Effects of row-type, row-spacing, seeding rate, soil-type, and cultivar differences on soybean seed nutrition under US Mississippi Delta conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Management practices such as seeding rate (SR), planting date (PD), and row-type (RT: single- and twin-rows) may alter seed nutrition in soybean. The objective of this research was to investigate the effects of SR and PD on soybean seed composition (protein, oil, fatty acids, and sugars) and mineral...

  13. Comparison of the effectiveness of using the optic strut and tuberculum sellae as radiological landmarks in diagnosing paraclinoid aneurysms with CT angiography.

    PubMed

    Liao, Chih-Hsiang; Lin, Chung-Jung; Lin, Chun-Fu; Huang, Hsin-Yi; Chen, Min-Hsiung; Hsu, Sanford P C; Shih, Yang-Hsin

    2016-08-01

    OBJECTIVE The treatment of paraclinoid aneurysms remains challenging. It is important to determine the exact location of the paraclinoid aneurysm when considering treatment options. The authors herein evaluated the effectiveness of using the optic strut (OS) and tuberculum sellae (TS) as radiographic landmarks for distinguishing between intradural and extradural paraclinoid aneurysms on source images from CT angiography (CTA). METHODS Between January 2010 and September 2013, a total of 49 surgical patients with the preoperative diagnoses of paraclinoid aneurysm and 1 symptomatic cavernous-clinoid aneurysm were retrospectively identified. With the source images from CTA, the OS and the TS were used as landmarks to predict the location of the paraclinoid aneurysm and its relation to the distal dural ring (DDR). The operative findings were examined to confirm the definitive location of the paraclinoid aneurysm. Statistical analysis was performed to determine the diagnostic effectiveness of the landmarks. RESULTS Nineteen patients without preoperative CTA were excluded. The remaining 30 patients comprised the current study. The intraoperative findings confirmed 12 intradural, 12 transitional, and 6 extradural paraclinoid aneurysms, the diagnoses of which were significantly related to the type of aneurysm (p < 0.05) but not factors like sex, age, laterality of aneurysm, or relation of the aneurysm to the ophthalmic artery on digital subtraction angiography. To measure agreement with the correct diagnosis, the OS as a reference point was far superior to the TS (Cohen's kappa coefficients 0.462 and 0.138 for the OS and the TS, respectively). For paraclinoid aneurysms of the medial or posterior type, using the base of the OS as a reference point tended to overestimate intradural paraclinoid aneurysms. The receiver operating characteristic curve indicated that if the aneurysmal neck traverses the axial plane 2 mm above the base of the OS, the aneurysm is most likely to grow

  14. Implications for dosimetric changes when introducing MR-guided brachytherapy for small volume cervix cancer: a comparison of CT and MR-based treatments in a single centre.

    PubMed

    Dempsey, Claire; Govindarajulu, Geetha; Sridharan, Swetha; Capp, Anne; O'Brien, Peter

    2014-12-01

    To evaluate cervix brachytherapy dosimetry with the introduction of magnetic resonance (MR) based treatment planning and volumetric prescriptions and propose a method for plan evaluation in the transition period. The treatment records of 69 patients were reviewed retrospectively. Forty one patients were treated using computed tomography (CT)-based, Point A-based prescriptions and 28 patients were treated using magnetic resonance (MR)-based, volumetric prescriptions. Plans were assessed for dose to Point A and organs at risk (OAR) with additional high-risk clinical target volume (HR-CTV) dose assessment for MR-based brachytherapy plans. ICRU-38 point doses and GEC-ESTRO recommended volumetric doses (D2cc for OAR and D100, D98 and D90 for HR-CTV) were also considered. For patients with small HR-CTV sizes, introduction of MR-based volumetric brachytherapy produced a change in dose delivered to Point A and OAR. Point A doses fell by 4.8 Gy (p = 0.0002) and ICRU and D2cc doses for OAR also reduced (p < 0.01). Mean Point A doses for MR-based brachytherapy treatment plans were closer to those of HR-CTV D100 for volumes less than 20 cm(3) and HR-CTV D98 for volumes between 20 and 35 cm(3), with a significant difference (p < 0.0001) between Point A and HR-CTV D90 doses in these ranges. In order to maintain brachytherapy dose consistency across varying HR-CTV sizes there must be a relationship between the volume of the HR-CTV and the prescription dose. Rather than adopting a 'one size fits all' approach during the transition to volume-based prescriptions, this audit has shown that separating prescription volumes into HR-CTV size categories of less than 20 cm(3), between 20 and 35 cm(3), and more than 35 cm(3) the HR-CTV can provide dose uniformity across all volumes and can be directly linked to traditional Point A prescriptions. PMID:25344886

  15. Image quality of CT angiography with model-based iterative reconstruction in young children with congenital heart disease: comparison with filtered back projection and adaptive statistical iterative reconstruction.

    PubMed

    Son, Sung Sil; Choo, Ki Seok; Jeon, Ung Bae; Jeon, Gye Rok; Nam, Kyung Jin; Kim, Tae Un; Yeom, Jeong A; Hwang, Jae Yeon; Jeong, Dong Wook; Lim, Soo Jin

    2015-06-01

    To retrospectively evaluate the image quality of CT angiography (CTA) reconstructed by model-based iterative reconstruction (MBIR) and to compare this with images obtained by filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) in newborns and infants with congenital heart disease (CHD). Thirty-seven children (age 4.8 ± 3.7 months; weight 4.79 ± 0.47 kg) with suspected CHD underwent CTA on a 64detector MDCT without ECG gating (80 kVp, 40 mA using tube current modulation). Total dose length product was recorded in all patients. Images were reconstructed using FBP, ASIR, and MBIR. Objective image qualities (density, noise) were measured in the great vessels and heart chambers. The contrast-to-noise ratio (CNR) was calculated by measuring the density and noise of myocardial walls. Two radiologists evaluated images for subjective noise, diagnostic confidence, and sharpness at the level prior to the first branch of the main pulmonary artery. Images were compared with respect to reconstruction method, and reconstruction times were measured. Images from all patients were diagnostic, and the effective dose was 0.22 mSv. The objective image noise of MBIR was significantly lower than those of FBP and ASIR in the great vessels and heart chambers (P < 0.05); however, with respect to attenuations in the four chambers, ascending aorta, descending aorta, and pulmonary trunk, no statistically significant difference was observed among the three methods (P > 0.05). Mean CNR values were 8.73 for FBP, 14.54 for ASIR, and 22.95 for MBIR. In addition, the subjective image noise of MBIR was significantly lower than those of the others (P < 0.01). Furthermore, while FBP had the highest score for image sharpness, ASIR had the highest score for diagnostic confidence (P < 0.05), and mean reconstruction times were 5.1 ± 2.3 s for FBP and ASIR and 15.1 ± 2.4 min for MBIR. While CTA with MBIR in newborns and infants with CHD can reduce image noise and

  16. Head CT (image)

    MedlinePlus

    CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the ... D image of a section through the body. CT scans are very detailed and provide excellent information ...

  17. CT scan (image)

    MedlinePlus

    CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the ... D image of a section through the body. CT scans are very detailed and provide excellent information ...

  18. CT appearance of splenosis

    SciTech Connect

    Mendelson, D.S.; Cohen, B.A.; Armas, R.R.

    1982-12-01

    Splenosis is an unusual complication of splenic trauma. The computed tomographic (CT) appearance of splenosis is described. One should consider this diagnosis when faced with a history of splenic trauma and multiple round or oval masses at CT.

  19. NETL CT Imaging Facility

    ScienceCinema

    None

    2014-05-21

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  20. NETL CT Imaging Facility

    SciTech Connect

    2013-09-04

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  1. Orbit CT scan

    MedlinePlus

    ... results may mean: Bleeding Broken eye socket bone Graves disease Infection Tumor Risks CT scans and other x- ... Livingstone; 2014:chap 66. Read More CT scan Graves disease Tumor Update Date 1/18/2015 Updated by: ...

  2. BER Performance Due to Irregularity of Row-Weight Distribution of the Parity-Check Matrix in Irregular LDPC Codes for 10-Gb/s Optical Signals

    NASA Astrophysics Data System (ADS)

    Youn, Jinhyun; Jang, Hodeok; Kim, Kyoungsoo; Jeong, Jichai

    2005-09-01

    Forward-error correction (FEC) coding is theoretically investigated to improve bit-error-rate (BER) performance in a 10-Gb/s optical transmission system using randomly irregular low-density parity-check (LDPC) codes, regular LDPC codes, and the Reed-Solomon (RS) (255,239) code as a comparison. The irregular LDPC codes has different row-weight variances of a parity-check matrix from 10.9 to 18.8 and a row-weight mean of 60. Simulation is carried out under various conditions including the impairment factors such as dispersion, polarization-mode dispersion (PMD), and fiber nonlinearities. Results suggest that the irregular LDPC code with a low row-weight variance (= 10.9) generally has better performance for the most impairment factors except for the factor of dispersion. On the other hand, for the factor of dispersion the irregular LDPC code performs better with a high row-weight variance (= 18.8). A specific LDPC code can overcome the impairment limits in a deployed link.

  3. SU-E-J-47: Comparison of Online Image Registrations of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac Imaging Systems

    SciTech Connect

    Li, J; Shi, W; Andrews, D; Werner-Wasik, M; Yu, Y; Liu, H

    2015-06-15

    Purpose To compare online image registrations of TrueBeam cone-beam CT (CBCT) and BrainLab ExacTrac imaging systems. Methods Tests were performed on a Varian TrueBeam STx linear accelerator (Version 2.0), which is integrated with a BrainLab ExacTrac imaging system (Version 6.0.5). The study was focused on comparing the online image registrations for translational shifts. A Rando head phantom was placed on treatment couch and immobilized with a BrainLab mask. The phantom was shifted by moving the couch translationally for 8 mm with a step size of 1 mm, in vertical, longitudinal, and lateral directions, respectively. At each location, the phantom was imaged with CBCT and ExacTrac x-ray. CBCT images were registered with TrueBeam and ExacTrac online registration algorithms, respectively. And ExacTrac x-ray image registrations were performed. Shifts calculated from different registrations were compared with nominal couch shifts. Results The averages and ranges of absolute differences between couch shifts and calculated phantom shifts obtained from ExacTrac x-ray registration, ExacTrac CBCT registration with default window, ExaxTrac CBCT registration with adjusted window (bone), Truebeam CBCT registration with bone window, and Truebeam CBCT registration with soft tissue window, were: 0.07 (0.02–0.14), 0.14 (0.01–0.35), 0.12 (0.02–0.28), 0.09 (0–0.20), and 0.06 (0–0.10) mm, in vertical direction; 0.06 (0.01–0.12), 0.27 (0.07–0.57), 0.23 (0.02–0.48), 0.04 (0–0.10), and 0.08 (0– 0.20) mm, in longitudinal direction; 0.05 (0.01–0.21), 0.35 (0.14–0.80), 0.25 (0.01–0.56), 0.19 (0–0.40), and 0.20 (0–0.40) mm, in lateral direction. Conclusion The shifts calculated from ExacTrac x-ray and TrueBeam CBCT registrations were close to each other (the differences between were less than 0.40 mm in any direction), and had better agreements with couch shifts than those from ExacTrac CBCT registrations. There were no significant differences between True

  4. Advances in CT imaging for urolithiasis

    PubMed Central

    Andrabi, Yasir; Patino, Manuel; Das, Chandan J.; Eisner, Brian; Sahani, Dushyant V.; Kambadakone, Avinash

    2015-01-01

    Urolithiasis is a common disease with increasing prevalence worldwide and a lifetime-estimated recurrence risk of over 50%. Imaging plays a critical role in the initial diagnosis, follow-up and urological management of urinary tract stone disease. Unenhanced helical computed tomography (CT) is highly sensitive (>95%) and specific (>96%) in the diagnosis of urolithiasis and is the imaging investigation of choice for the initial assessment of patients with suspected urolithiasis. The emergence of multi-detector CT (MDCT) and technological innovations in CT such as dual-energy CT (DECT) has widened the scope of MDCT in the stone disease management from initial diagnosis to encompass treatment planning and monitoring of treatment success. DECT has been shown to enhance pre-treatment characterization of stone composition in comparison with conventional MDCT and is being increasingly used. Although CT-related radiation dose exposure remains a valid concern, the use of low-dose MDCT protocols and integration of newer iterative reconstruction algorithms into routine CT practice has resulted in a substantial decrease in ionizing radiation exposure. In this review article, our intent is to discuss the role of MDCT in the diagnosis and post-treatment evaluation of urolithiasis and review the impact of emerging CT technologies such as dual energy in clinical practice. PMID:26166961

  5. Advances in CT imaging for urolithiasis.

    PubMed

    Andrabi, Yasir; Patino, Manuel; Das, Chandan J; Eisner, Brian; Sahani, Dushyant V; Kambadakone, Avinash

    2015-01-01

    Urolithiasis is a common disease with increasing prevalence worldwide and a lifetime-estimated recurrence risk of over 50%. Imaging plays a critical role in the initial diagnosis, follow-up and urological management of urinary tract stone disease. Unenhanced helical computed tomography (CT) is highly sensitive (>95%) and specific (>96%) in the diagnosis of urolithiasis and is the imaging investigation of choice for the initial assessment of patients with suspected urolithiasis. The emergence of multi-detector CT (MDCT) and technological innovations in CT such as dual-energy CT (DECT) has widened the scope of MDCT in the stone disease management from initial diagnosis to encompass treatment planning and monitoring of treatment success. DECT has been shown to enhance pre-treatment characterization of stone composition in comparison with conventional MDCT and is being increasingly used. Although CT-related radiation dose exposure remains a valid concern, the use of low-dose MDCT protocols and integration of newer iterative reconstruction algorithms into routine CT practice has resulted in a substantial decrease in ionizing radiation exposure. In this review article, our intent is to discuss the role of MDCT in the diagnosis and post-treatment evaluation of urolithiasis and review the impact of emerging CT technologies such as dual energy in clinical practice. PMID:26166961

  6. Accuracy of Ultrasound-Based Image Guidance for Daily Positioning of the Upper Abdomen: An Online Comparison With Cone Beam CT

    SciTech Connect

    Boda-Heggemann, Judit Mennemeyer, Philipp; Wertz, Hansjoerg; Riesenacker, Nadja; Kuepper, Beate; Lohr, Frank; Wenz, Frederik

    2009-07-01

    Purpose: Image-guided intensity-modulated radiotherapy can improve protection of organs at risk when large abdominal target volumes are irradiated. We estimated the daily positioning accuracy of ultrasound-based image guidance for abdominal target volumes by a direct comparison of daily imaging obtained with cone beam computed tomography (CBCT). Methods and Materials: Daily positioning (n = 83 positionings) of 15 patients was completed by using ultrasound guidance after an initial CBCT was obtained. Residual error after ultrasound was estimated by comparison with a second CBCT. Ultrasound image quality was visually rated using a scale of 1 to 4. Results: Of 15 patients, 7 patients had good sonographic imaging quality, 5 patients had satisfactory sonographic quality, and 3 patients were excluded because of unsatisfactory sonographic quality. When image quality was good, residual errors after ultrasound were -0.1 {+-} 3.11 mm in the x direction (left-right; group systematic error M = -0.09 mm; standard deviation [SD] of systematic error, {sigma} = 1.37 mm; SD of the random error, {sigma} = 2.99 mm), 0.93 {+-} 4.31 mm in the y direction (superior-inferior, M = 1.12 mm; {sigma} = 2.96 mm; {sigma} = 3.39 mm), and 0.71 {+-} 3.15 mm in the z direction (anteroposterior; M = 1.01 mm; {sigma} = 2.46 mm; {sigma} = 2.24 mm). For patients with satisfactory image quality, residual error after ultrasound was -0.6 {+-} 5.26 mm in the x (M = 0.07 mm; {sigma} = 5.67 mm; {sigma} = 4.86 mm), 1.76 {+-} 4.92 mm in the y (M = 3.54 mm; {sigma} = 4.1 mm; {sigma} = 5.29 mm), and 1.19 {+-} 4.75 mm in the z (M = 0.82 mm; {sigma} = 2.86 mm; {sigma} = 3.05 mm) directions. Conclusions: In patients from whom good sonographic image quality could be obtained, ultrasound improved daily positioning accuracy. In the case of satisfactory image quality, ultrasound guidance improved accuracy compared to that of skin marks only minimally. If sonographic image quality was unsatisfactory, daily CBCT

  7. The Energetic Assessment of Frictional Instability Based on Rowe's Theory

    NASA Astrophysics Data System (ADS)

    Hirata, M.; Muto, J.; Nagahama, H.

    2015-12-01

    Frictional instability that controls the occurrence of unstable slips has been related to (1) rate and state dependent friction law (Dieterich, 1979; Ruina, 1983) and (2) shear localization in a gouge layer (e.g., Byerlee et al., 1978; Logan et al., 1979). Ikari et al. (2011) indicated that the transitions of frictional parameters obtained from the rate and state dependent friction law involve shear localization. However, the underlining theoretical background for their link has been unknown. Therefore, in this study, we investigate their relation theoretically and experimentally based on Rowe's theory on constant minimum energy ratio (Rowe, 1962) describing particle deformations quantitatively by energetic analysis. In theoretical analysis using analytical dynamics and irreversible thermodynamics, the energetic criterion about frictional instability is obtained; unstable slip occurs at energy ratios below 1. In friction experiments using a gas medium apparatus, simulated fault gouge deforms obeying the Rowe's theory. Additionally, the energy ratios change gradually with shear and show below 1 before the occurrence of unstable slip. Moreover, energy ratios are derived from volume changes. Transition of energy ratios from increase to decrease, which has been confirmed at the end of compaction, indicates the onset of volume increase toward the occurrence of unstable slip. The volume increases likely correspond to the formation of R1-shears with open mode character, which occurs prior to the unstable slip. Shear localization leads to a change in internal friction angle which is a statistical parameter to constitute a energy ratio. In short, changes in internal friction angle play an important role in evolving from being frictionally stable to unstable. From these results, the physical and energetic background for their link between the frictional parameter and shear localization becomes clear.

  8. Plant, soil, and shadow reflectance components of row crops

    NASA Technical Reports Server (NTRS)

    Richardson, A. J.; Wiegand, C. L.; Gausman, H. W.; Cuellar, J. A.; Gerbermann, A. H.

    1975-01-01

    Data from the first Earth Resource Technology Satellite (LANDSAT-1) multispectral scanner (MSS) were used to develop three plant canopy models (Kubelka-Munk (K-M), regression, and combined K-M and regression models) for extracting plant, soil, and shadow reflectance components of cropped fields. The combined model gave the best correlation between MSS data and ground truth, by accounting for essentially all of the reflectance of plants, soil, and shadow between crop rows. The principles presented can be used to better forecast crop yield and to estimate acreage.

  9. 9. Detail view of columns on first floor. This row ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Detail view of columns on first floor. This row of columns indicates the former location of the exterior mill wall before World War II era expansion. The unusual column and beam connection was a key part of the mill structural system patented by Providence, Rhode Island engineers Charles Praray and Charles Makepeace in 1894. Each column was originally located in the apex of triangular window bay, but not connected to the exterior wall. Modifications on the right side of each column support the beams of the addition. - Dixie Cotton Mill, 710 Greenville Street, La Grange, Troup County, GA

  10. Film cooling: case of double rows of staggered jets.

    PubMed

    Dorignac, E; Vullierme, J J; Noirault, P; Foucault, E; Bousgarbiès, J L

    2001-05-01

    An experimental investigation of film cooling of a wall in a case of double rows of staggered hot jets (65 degrees C) in an ambient air flow. The wall is heated at a temperature value between the one of the jets and the one of the main flow. Experiments have been carried out for different injection rates, the main flow velocity is maintained at 32 m/s. Association of the measures of temperature profiles by cold wire and the measures of wall temperature by infrared thermography allows us to describe the behaviour of the flows and to propose the best injection which assures a good cooling of the plate. PMID:11460645

  11. Marketing cardiac CT programs.

    PubMed

    Scott, Jason

    2010-01-01

    There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing. PMID:22276376

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

    PubMed Central

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

    2015-01-01

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

  13. Muscle Synergies of Untrained Subjects during 6 min Maximal Rowing on Slides and Fixed Ergometer

    PubMed Central

    Shaharudin, Shazlin; Zanotto, Damiano; Agrawal, Sunil

    2014-01-01

    The slides ergometer (SE) was an improvisation from fixed ergometer (FE) to bridge the gap of mechanics between ergometer rowing and on-water rowing. The specific mechanical constraints of these two types of ergometers may affect the pattern of muscle recruitment, coordination and adaptation. The main purpose of this study was to evaluate the muscle synergy during 6 minutes maximal rowing on slides (SE) and fixed ergometers (FE). The laterality of muscle synergy was also examined. Surface electromyography activity, power output, heart rate, stroke length and stroke rate were analyzed from nine physically active subjects to assess the rowing performance. Physically active subjects, who were not specifically trained in rowing, were chosen to exclude the training effect on muscle synergy. Principal component analysis (PCA) with varimax rotation was applied to extract muscle synergy. Three muscle synergies were sufficient to explain the majority of variance in SE (94.4 ± 2.2 %) and FE (92.8 ± 1.7 %). Subjects covered more rowing distance, exerted greater power output and attained higher maximal heart rate during rowing on SE than on FE. The results proved the flexibility of muscle synergy to adapt to the mechanical constraints. Rowing on SE emphasized on bi-articular muscles contrary to rowing on FE which relied on cumulative effect of trunk and upper limb muscles during propulsive phase. Key points Three muscle synergies were extracted during maximal rowing on both fixed and slides ergometer Untrained subjects emphasized leg muscles while rowing on SE Untrained subjects focused on back muscles during FE rowing PMID:25435771

  14. Muscle Synergies of Untrained Subjects during 6 min Maximal Rowing on Slides and Fixed Ergometer.

    PubMed

    Shaharudin, Shazlin; Zanotto, Damiano; Agrawal, Sunil

    2014-12-01

    The slides ergometer (SE) was an improvisation from fixed ergometer (FE) to bridge the gap of mechanics between ergometer rowing and on-water rowing. The specific mechanical constraints of these two types of ergometers may affect the pattern of muscle recruitment, coordination and adaptation. The main purpose of this study was to evaluate the muscle synergy during 6 minutes maximal rowing on slides (SE) and fixed ergometers (FE). The laterality of muscle synergy was also examined. Surface electromyography activity, power output, heart rate, stroke length and stroke rate were analyzed from nine physically active subjects to assess the rowing performance. Physically active subjects, who were not specifically trained in rowing, were chosen to exclude the training effect on muscle synergy. Principal component analysis (PCA) with varimax rotation was applied to extract muscle synergy. Three muscle synergies were sufficient to explain the majority of variance in SE (94.4 ± 2.2 %) and FE (92.8 ± 1.7 %). Subjects covered more rowing distance, exerted greater power output and attained higher maximal heart rate during rowing on SE than on FE. The results proved the flexibility of muscle synergy to adapt to the mechanical constraints. Rowing on SE emphasized on bi-articular muscles contrary to rowing on FE which relied on cumulative effect of trunk and upper limb muscles during propulsive phase. Key pointsThree muscle synergies were extracted during maximal rowing on both fixed and slides ergometerUntrained subjects emphasized leg muscles while rowing on SEUntrained subjects focused on back muscles during FE rowing. PMID:25435771

  15. PET/CT-Based Dosimetry in 90Y-Microsphere Selective Internal Radiation Therapy: Single Cohort Comparison With Pretreatment Planning on 99mTc-MAA Imaging and Correlation With Treatment Efficacy

    PubMed Central

    Song, Yoo Sung; Paeng, Jin Chul; Kim, Hyo-Cheol; Chung, Jin Wook; Cheon, Gi Jeong; Chung, June-Key; Lee, Dong Soo; Kang, Keon Wook

    2015-01-01

    Abstract 90Y PET/CT can be acquired after 90Y-microsphere selective radiation internal therapy (SIRT) to describe radioactivity distribution. We performed dosimetry using 90Y-microsphere PET/CT data to evaluate treatment efficacy and appropriateness of activity planning from 99mTc-MAA scan and SPECT/CT. Twenty-three patients with liver malignancy were included in the study. 99mTc-MAA was injected during planning angiography and whole body 99mTc-MAA scan and liver SPECT/CT were acquired. After SIRT using 90Y-resin microsphere, 90Y-microsphere PET/CT was acquired. A partition model (PM) using 4 compartments (tumor, intarget normal liver, out-target normal liver, and lung) was adopted, and absorbed dose to each compartment was calculated based on measurements from 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT, respectively, to be compared with each other. Progression-free survival (PFS) was evaluated in terms of tumor absorbed doses calculated by 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT results. Lung shunt fraction was overestimated on 99mTc-MAA scan compared with 90Y-microsphere PET/CT (0.060 ± 0.037 vs. 0.018 ± 0.026, P < 0.01). Tumor absorbed dose exhibited a close correlation between the results from 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT (r = 0.64, P < 0.01), although the result from 99mTc-MAA SPECT/CT was significantly lower than that from 90Y-microsphere PET/CT (135.4 ± 64.2 Gy vs. 185.0 ± 87.8 Gy, P < 0.01). Absorbed dose to in-target normal liver was overestimated on 99mTc-MAA SPECT/CT compared with PET/CT (62.6 ± 38.2 Gy vs. 45.2 ± 32.0 Gy, P = 0.02). Absorbed dose to out-target normal liver did not differ between 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT (P = 0.49). Patients with tumor absorbed dose >200 Gy on 90Y-microsphere PET/CT had longer PFS than those with tumor absorbed dose ≤200 Gy (286 ± 56 days vs. 92 ± 20 days, P = 0.046). Tumor absorbed dose calculated by 99m

  16. Evaluation of organ doses in CT examinations with an infant anthropomorphic phantom.

    PubMed

    Fujii, K; Akahane, K; Miyazaki, O; Horiuchi, T; Shimada, A; Nagmatsu, H; Yamauchi, M; Yamauchi-Kawaura, C; Kawasaki, T

    2011-09-01

    The aim of this study is to evaluate organ doses in infant CT examinations with multi-detector row CT scanners. Radiation doses were measured with radiophotoluminescence glass dosemeters set in various organ positions within a 1-y-old child anthropomorphic phantom and organ doses were evaluated from the measurement values. Doses for tissues or organs within the scan range were 28-36 mGy in an infant head CT, 3-11 mGy in a chest CT, 5-11 mGy in an abdominal-pelvic CT and 2-14 mGy in a cardiac CT. The doses varied by the differences in the types of CT scanners and scan parameters used at each medical facility. Compared with those for children of various ages, the doses in an infant CT protocol were found to be similar to or slightly smaller than those in a paediatric CT for 5- or 6-y-old children. PMID:21743079

  17. Paleoradiology: advanced CT in the evaluation of nine Egyptian mummies.

    PubMed

    Hoffman, Heidi; Torres, William E; Ernst, Randy D

    2002-01-01

    Axial thin-collimation state-of-the-art spiral computed tomography (CT) was combined with sagittal and coronal reformatting, three-dimensional (3D) reconstruction, and virtual "fly-through" techniques to nondestructively study nine Egyptian mummies. These techniques provided important paleopathologic and historical information about mummification techniques, depicted anatomy in the most informative imaging plane, illustrated the soft-tissue preservation and physical appearance of mummies in superb detail, and generated an intriguing virtual tour through hollow mummified remains without harming the specimens themselves. Images generated with these methods can help archaeologists and Egyptologists understand these fascinating members of mankind and can serve as adjunct visual aids for laypersons who are interested in mummies. CT has emerged as the imaging modality of choice for the examination of Egyptian mummies due to its noninvasive cross-sectional nature and inherently superior contrast and spatial resolution. As multi-detector row CT and postprocessing tools evolve, the capabilities and applications of CT will continue to proliferate, attesting to the expanded versatility and utility of CT as a noninvasive research tool in the multidisciplinary study of Egyptian mummies. PMID:11896227

  18. Development of Magnetorheological Resistive Exercise Device for Rowing Machine.

    PubMed

    Grigas, Vytautas; Šulginas, Anatolijus; Žiliukas, Pranas

    2015-01-01

    Training equipment used by professional sportsmen has a great impact on their sport performance. Most universal exercisers may help only to improve the general physical condition due to the specific kinematics and peculiar resistance generated by their loading units. Training of effective techniques and learning of psychomotor skills are possible only when exercisers conform to the movements and resistance typical for particular sports kinematically and dynamically. Methodology of developing a magnetorheological resistive exercise device for generating the desired law of passive resistance force and its application in a lever-type rowing machine are described in the paper. The structural parameters of a controllable hydraulic cylinder type device were found by means of the computational fluid dynamics simulation performed by ANSYS CFX software. Parameters describing the magnetorheological fluid as non-Newtonian were determined by combining numerical and experimental research of the resistance force generated by the original magnetorheological damper. A structural scheme of the device control system was developed and the variation of the strength of magnetic field that affects the magnetorheological fluid circulating in the device was determined, ensuring a variation of the resistance force on the oar handle adequate for the resistance that occurs during a real boat rowing stroke. PMID:27293479

  19. Development of Magnetorheological Resistive Exercise Device for Rowing Machine

    PubMed Central

    Žiliukas, Pranas

    2016-01-01

    Training equipment used by professional sportsmen has a great impact on their sport performance. Most universal exercisers may help only to improve the general physical condition due to the specific kinematics and peculiar resistance generated by their loading units. Training of effective techniques and learning of psychomotor skills are possible only when exercisers conform to the movements and resistance typical for particular sports kinematically and dynamically. Methodology of developing a magnetorheological resistive exercise device for generating the desired law of passive resistance force and its application in a lever-type rowing machine are described in the paper. The structural parameters of a controllable hydraulic cylinder type device were found by means of the computational fluid dynamics simulation performed by ANSYS CFX software. Parameters describing the magnetorheological fluid as non-Newtonian were determined by combining numerical and experimental research of the resistance force generated by the original magnetorheological damper. A structural scheme of the device control system was developed and the variation of the strength of magnetic field that affects the magnetorheological fluid circulating in the device was determined, ensuring a variation of the resistance force on the oar handle adequate for the resistance that occurs during a real boat rowing stroke. PMID:27293479

  20. Directional reflectance factor distributions of a cotton row crop

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.; Newcomb, W. W.; Schutt, J. B.; Pinter, P. J., Jr.; Jackson, R. D.

    1984-01-01

    The directional reflectance factor distribution spanning the entire exitance hemisphere was measured for a cotton row crop (Gossypium barbadense L.) with 39 percent ground cover. Spectral directional radiances were taken in NOAA satellite 7 AVHRR bands 1 and 2 using a three-band radiometer with restricted 12 deg full angle field of view at half peak power points. Polar co-ordinate system plots of directional reflectance factor distributions and three-dimensional computer graphic plots of scattered flux were used to study the dynamics of the directional reflectance factor distribution as a function of spectral band, geometric structure of the scene, solar zenith and azimuth angles, and optical properties of the leaves and soil. The factor distribution of the incomplete row crops was highly polymodal relative to that for complete vegetation canopies. Besides the enhanced reflectance for the antisolar point, a reflectance minimum was observed towards the forwardscatter direction in the principle plane of the sun. Knowledge of the mechanics of the observed dynamics of the data may be used to provide rigorous validation for two- or three-dimensional radiative transfer models, and is important in interpreting aircraft and satellite data where the solar angle varies widely.

  1. Transitions of flow past a row of square bars

    NASA Astrophysics Data System (ADS)

    Mizushima, J.; Kawaguchi, Y.

    2000-02-01

    Transitions of flow past a row of square bars placed across a uniform flow are investigated by numerical simulations and the bifurcation analysis of the numerical results. The flow is assumed two-dimensional and incompressible. It is already known that jets coming through gaps between square bars are independent of each other when the pitch-to-side-length ratio of the row is large, whereas the confluence of two or three jets occurs due to a first pitchfork bifurcation from the flow with independent jets when the pitch-to-side-length ratio is small. It is found that confluence of four jets occurs in consequence of the second pitchfork bifurcation from the flow with pairs of jets joined to each other. Bifurcation diagrams of the flow are obtained, which include confluences of double, triple and quadruple jets. Lengths of the twin vortices are evaluated for each flow pattern. The confluences of two, three and four jets are qualitatively confirmed experimentally by flow visualizations.

  2. Multifractal analyses of row sum signals of elementary cellular automata

    NASA Astrophysics Data System (ADS)

    Murguía, J. S.; Rosu, H. C.

    2012-07-01

    We first apply the WT-MFDFA, MFDFA, and WTMM multifractal methods to binomial multifractal time series of three different binomial parameters and find that the WTMM method indicates an enhanced difference between the fractal components than the known theoretical result. Next, we make use of the same methods for the time series of the row sum signals of the two complementary ECA pairs of rules (90,165) and (150,105) for ten initial conditions going from a single 1 in the central position up to a set of ten 1's covering the ten central positions in the first row. Since the members of the pairs are actually similar from the statistical point of view, we can check which method is the most stable numerically by recording the differences provided by the methods between the two members of the pairs for various important quantities of the scaling analyses, such as the multifractal support, the most frequent Hölder exponent, and the Hurst exponent and considering as the better one the method that provides the minimum differences. According to this criterion, our results show that the MFDFA performs better than WT-MFDFA and WTMM in the case of the multifractal support, while for the other two scaling parameters the WT-MFDFA is the best. The employed set of initial conditions does not generate any specific trend in the values of the multifractal parameters.

  3. Prognostic Value of FDG-PET, Based on the Revised Response Criteria, in Patients with Malignant Lymphoma: A Comparison with CT/MRI Evaluations, Based on the International Working Group/Cotswolds Meeting Criteria

    PubMed Central

    Isohashi, Kayako; Tatsumi, Mitsuaki; Kato, Hiroki; Fukushima, Kentaro; Maeda, Tetsuo; Watabe, Tadashi; Shimosegawa, Eku; Kanakura, Yuzuru; Hatazawa, Jun

    2015-01-01

    Objective(s): Post-treatment evaluations by CT/MRI (based on the International Working Group/Cotswolds meeting guidelines) and PET (based on Revised Response Criteria), were examined in terms of progression-free survival (PFS) in patients with malignant lymphoma (ML). Methods: 79 patients, undergoing CT/MRI for the examination of suspected lesions and whole-body PET/CT before and after therapy, were included in the study during April 2007-January 2013. The relationship between post-treatment evaluations (CT/MRI and PET) and PFS during the follow-up period was examined, using Kaplan-Meier survival analysis. The patients were grouped according to the histological type into Hodgkin’s lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and other histological types. The association between post-treatment evaluations (PET or PET combined with CT/MRI) and PFS was examined separately. Moreover, the relationship between disease recurrence and serum soluble interleukin-2 receptor, lactic dehydrogenase, and C-reactive protein levels was evaluated before and after the treatment. Results: Patients with incomplete remission on both CT/MRI and PET had a significantly shorter PFS, compared to patients with complete remission on both CT/MRI and PET and those exhibiting incomplete remission on CT/MRI and complete remission on PET (P<0.001). Post-treatment PET evaluations were strongly correlated with patient outcomes in cases with HL or DLBCL (P<0.01) and other histological types (P<0.001). In patients with HL or DLBCL, incomplete remission on both CT/MRI and PET was associated with a significantly shorter PFS, compared to patients with complete remission on both CT/MRI and PET (P<0.05) and those showing incomplete remission on CT/MRI and complete remission on PET (P<0.01). In patients with other histological types, incomplete remission on both CT/MRI and PET was associated with a significantly shorter PFS, compared to cases with complete remission on both CT/MRI and PET (P<0

  4. Validity of blood flow measurement using 320 multi-detectors CT and first-pass distribution theory: a phantom study

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Yu, Xuefang; Xu, Shaopeng; Zhou, Kenneth J.

    2015-03-01

    To evaluate the feasibility of measuring the myocardial blood flow using 320 row detector CT by first-pass technique. Heart was simulated with a container that was filled with pipeline of 3mm diameter; coronary artery was simulated with a pipeline of 2 cm diameter and connected with the simulated heart. The simulated coronary artery was connected with a big container with 1500 ml saline and 150ml contrast agent. One pump linking with simulated heart will withdraw with a speed of 10 ml/min, 15 ml/min, 20 ml/min, 25 ml/min and 30 ml/min. First CT scan starts after 30 s of pumpback with certain speed. The second CT scan starts 5 s after first CT scans. CT images processed as follows: The second CT scan images subtract first CT scan images, calculate the increase of CT value of simulated heart and the CT value of the unit volume of simulated coronary artery and then to calculate the total inflow of myocardial blood flow. CT myocardial blood flows were calculated as: 0.94 ml/s, 2.09 ml/s, 2.74 ml/s, 4.18 ml/s, 4.86 ml/s. The correlation coefficient is 0.994 and r2 = 0.97. The method of measuring the myocardial blood flow using 320 row detector CT by 2 scans is feasible. It is possible to develop a new method for quantitatively and functional assessment of myocardial perfusion blood flow with less radiation does.

  5. Comparison of {sup 18}F-Fluorothymidine and {sup 18}F-Fluorodeoxyglucose PET/CT in Delineating Gross Tumor Volume by Optimal Threshold in Patients With Squamous Cell Carcinoma of Thoracic Esophagus

    SciTech Connect

    Han Dali; Yu Jinming; Yu Yonghua; Zhang Guifang; Zhong Xiaojun; Lu Jie; Yin Yong; Fu Zheng; Mu Dianbin; Zhang Baijiang; He Wei; Huo Zhijun; Liu Xijun; Kong Lei; Zhao Shuqiang; Sun Xiangyu

    2010-03-15

    Purpose: To determine the optimal method of using {sup 18}F-fluorothymidine (FLT) positron emission tomography (PET)/computed tomography (CT) simulation to delineate the gross tumor volume (GTV) in esophageal squamous cell carcinoma verified by pathologic examination and compare the results with those using {sup 18}F-fluorodeoxyglucose (FDG) PET/CT. Methods and Materials: A total of 22 patients were enrolled and underwent both FLT and FDG PET/CT. The GTVs with biologic information were delineated using seven different methods in FLT PET/CT and three different methods in FDG PET/CT. The results were compared with the pathologic gross tumor length, and the optimal threshold was obtained. Next, we compared the simulation plans using the optimal threshold of FLT and FDG PET/CT. The radiation dose was prescribed as 60 Gy in 30 fractions with a precise radiotherapy technique. Results: The mean +- standard deviation pathologic gross tumor length was 4.94 +- 2.21 cm. On FLT PET/CT, the length of the standardized uptake value 1.4 was 4.91 +- 2.43 cm. On FDG PET/CT, the length of the standardized uptake value 2.5 was 5.10 +- 2.18 cm, both of which seemed more approximate to the pathologic gross tumor length. The differences in the bilateral lung volume receiving >=20 Gy, heart volume receiving >=40 Gy, and the maximal dose received by spinal cord between FLT and FDG were not significant. However, the values for mean lung dose, bilateral lung volume receiving >=5, >=10, >=30, >=40, and >=50 Gy, mean heart dose, and heart volume receiving >=30 Gy using FLT PET/CT-based planning were significant lower than those using FDG PET/CT. Conclusion: A standardized uptake value cutoff of 1.4 on FLT PET/CT and one of 2.5 on FDG PET/CT provided the closest estimation of GTV length. Finally, FLT PET/CT-based treatment planning provided potential benefits to the lungs and heart.

  6. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a good'' surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  7. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a ``good`` surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  8. Practical CT dosimetry

    SciTech Connect

    Yoshizumi, T.T.; Suneja, S.K.; Teal, J.S. )

    1989-07-01

    The dose from computed tomography (CT) examinations is not negligible from a radiation safety standpoint. Occasionally, one encounters a case in which an unsuspected pregnant woman undergoes a CT pelvic scan, and the radiologist is required to estimate the dose to the fetus. This article addresses practical methods of CT dosimetry with a specific discussion on fetal dose estimate. Three methods are described: (1) the use of a dose chart, (2) the pencil ionization chamber method, and (3) the thermoluminescence dosimetry (TLD) method.

  9. CT findings in leukemia

    SciTech Connect

    Heiberg, E.; Wolverson, M.K.; Sundaram, M.; Shields, J.B.

    1984-12-01

    Review of 84 computed tomographic (CT) scans in leukemic patients demonstrate a wide spectrum of abnormalities. Findings caused by leukemia were lymphadenopathy, visceral enlargement, focal defects, and tissue infiltration. Hemorrhage was by far the most common complication and could usually be characterized on the noncontrast CT scan. The distinction between old hematomas, foci of infection, and leukemia infiltration could not be made with certainty without CT-guided aspiration. Unusual instances of sepsis, such as microabscesses of the liver and typhlitis, were seen.

  10. PET/CT Artifacts

    PubMed Central

    Blodgett, Todd M.; Mehta, Ajeet S.; Mehta, Amar S.; Laymon, Charles M.; Carney, Jonathan; Townsend, David W.

    2014-01-01

    There are several artifacts encountered in PET/CT imaging, including attenuation correction (AC) artifacts associated with using CT for attenuation correction. Several artifacts can mimic a 2-deoxy-2-[18F] fluoro-D-glucose (FDG) avid malignant lesions and therefore recognition of these artifacts is clinically relevant. Our goal was to identify and characterize these artifacts and also discuss some protocol variables that may affect image quality in PET/CT. PMID:21237418

  11. Building Generalized Inverses of Matrices Using Only Row and Column Operations

    ERIC Educational Resources Information Center

    Stuart, Jeffrey

    2010-01-01

    Most students complete their first and only course in linear algebra with the understanding that a real, square matrix "A" has an inverse if and only if "rref"("A"), the reduced row echelon form of "A", is the identity matrix I[subscript n]. That is, if they apply elementary row operations via the Gauss-Jordan algorithm to the partitioned matrix…

  12. Implements and cultivation frequency to improve in-row weed control in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic peanut production is difficult and costly, which limits expansion of the production system. Sweep cultivation in the row middles is effective, but weeds remain in the crop row causing yield loss. Research trials were conducted in Tifton, GA to evaluate implements and freque...

  13. Registration of nineteen spring six-rowed barley germplasm lines resistant to Russian wheat aphid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Russian wheat aphid (RWA) is a new and devastating pest of barley in the western US. No resistance was found in US cultivars whether two-row, six-row, malt, feed, spring or winter. A screening of the entire collection of barley accessions in the National Small Grains Collection by the USDA-ARS in ...

  14. ROW PATTERN, PLANT DENSITY, AND NITROGEN RATE ON CORN YIELD IN THE SOUTHEASTERN US.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is uncertain how corn (Zea mays L.) yield would be affected by planting in a twin-row orientation in the southeast. The objectives were to compare corn grain yield when: 1) planted in single and twin-rows, 2) plant densities at recommended (1R) and twice the recommended (2R) rate, and 3) nitrogen...

  15. Soil Water Extraction Patterns in Skip Row Corn, Sorghum, and Sunflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growing crops in planting configurations that increase row spacing while maintaining field plant populations (skip row) has been proposed as a means to stabilize dryland crop yields under the erratic and sometimes very low precipitation conditions that frequently exit in the Great Plains. Doing so s...

  16. Three year evaluation of corn production on narrow rows on the Southeastern Coastal Plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the use of hybrids with upright leaf architecture, and more sophisticated cropping systems there is an increased use narrow row production systems. Midwest and northern corn producers have begun to migrate to a 38 cm (15”) row spacing while southern cropping systems have considered a 46 to 61 c...

  17. Skip-row Corn and Sorghum in the West Central Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Skip-row planting of corn and sorghum has recently developed as a strategy for mitigating drought in the dryland regions of the western Central Great Plains. Here we compare 16 site-years of no-till feed grain yields when planted skip-row and when planted conventionally in Eastern Colorado and Weste...

  18. Registration of seventeen spring two-rowed barley germplasm lines resistant to Russian wheat aphid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Russian wheat aphid (RWA) is a new and devastating pest of barley in the western US. No resistance was found in US cultivars whether two-row, six-row, malt, feed, spring or winter. A screening of the entire collection of barley accessions in the National Small Grains Collection by the USDA-ARS in ...

  19. STS-42 Commander Grabe uses DTO 653 MK1 Rowing Machine on OV-103's middeck

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-42 Commander Ronald J. Grabe exercises using MK1 Rowing Machine on the middeck of Discovery, Orbiter Vehicle (OV) 103. Grabe is using the exercise device as part of Development Test Objective (DTO) 653, Evaluation of MK1 Rowing Machine. The forward lockers appear at Grabe's right and the sleep station behind him.

  20. Radiation Balance and Evaporation Partitioning in a Narrow-row Soybean Canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seeding rate and row spacing of agricultural crops are managed to maximize yield but also have significant implications for canopy microclimate and turbulent exchange processes. The objective of this study was to complete a comprehensive radiation budget for a narrow-row (0.38-m) soybean [Glycine m...

  1. 76 FR 41532 - Yankee Atomic Electric Company, Yankee Nuclear Power Station (Yankee-Rowe); Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-14

    ... accordance with the NRC E-Filing rule (72 FR 49139, August 28, 2007). The E-Filing process requires... COMMISSION Yankee Atomic Electric Company, Yankee Nuclear Power Station (Yankee-Rowe); Notice of...-Rowe), currently held by Yankee Atomic Electric Company (YAEC), as owner and licensed operator...

  2. Radiometer footprint model to estimate sunlit and shaded components for row crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes a geometric model for computing the relative proportion of sunlit vegetation, shaded vegetation, sunlit soil, and shaded soil appearing in a circular or elliptical radiometer footprint for row crops, where the crop rows were modeled as continuous ellipses. The model was validate...

  3. Effects of an Aerobic Rowing Training Regimen in Young Adults with Down Syndrome.

    ERIC Educational Resources Information Center

    Varela, Ana Maria; Sardinha, Luis Bettencount; Pitetti, Kenneth H.

    2001-01-01

    Eight young adult males with Down syndrome received a 16-week rowing ergometry training regimen. Following training, no changes in cardiovascular fitness were found but participants did achieve significantly higher levels of work performance on both treadmill and rowing ergometer tests than did a control group. (Contains references.) (Author/DB)

  4. Inter-row evapotranspiration in arid and humid wine-grape vineyards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The architecture of wine-grape vineyards is characterized by tall plants (approx. 1.5 m) and widely spaced rows (approx. 3 m). This wide row spacing, developed to allow sunlight interception, air flow, and field operations, creates a complex system for water and energy budgets. Because of the wide r...

  5. The effects of color plastic mulches and row covers on the growth and yield of okra

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Okra [Abelmoschus esculentus (l.) Moench'Clemson Spineless'] was grown on an Orangeburg sandy loam soil in shorter, AL. Okra was direct seeded in single rows. The experiment consisted of twelve experimental treatments as follows: (1) Black plastic mulch (BPM) + spunbonded row cover (RC), (2) BPM, (3...

  6. Plastic Mulches and Row Covers on the grow and production of Summer Squash.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Summer squash [Cucurbita pepo (L) ‘Prelude II’] was grown on an Orangeburg sandy loam soil in Shorter, AL. The summer squash was direct seeded in single rows. The experiment consisted of twelve experimental treatments as follows: (1) Black plastic mulch (BPM) + spunbonded row cover (RC), (2) BPM, (...

  7. Rowing increases stroke volume and cardiac output to a greater extent than cycling.

    PubMed

    Horn, P; Ostadal, P; Ostadal, B

    2015-01-01

    Exercise stimulates increases in heart rate (HR), stroke volume (SV) and cardiac output (CO). These adaptive mechanisms are strongly dependent on the type of exercise. Both rowing and cycling are widely used for physical training worldwide; however, evidence regarding the differences in major hemodynamic parameters during rowing and cycling remains insufficient. Ten healthy male volunteers were randomly assigned to perform either a rowing or cycling exercise. After 20 min rest, the group who had rowed first performed the cycling exercise and vice versa. Exercise was performed at a power-to-weight ratio of 2 W/kg for 2 min. HR, SV, CO and blood pressure (BP) were measured noninvasively using pulse-wave analysis at baseline and immediately after each exercise. HR, SV and CO were significantly higher after exercise than at rest. Whereas HR was comparable between rowing and cycling, SV and CO were significantly higher after rowing than after cycling. BP was comparable among all three measurements. Rowing increased SV and CO to a greater extent than cycling, whereas HR and BP were not influenced by the type of exercise. Our data suggest that rowing leads to more extensive stimulation of cardiac contractility and/or decreases in peripheral vascular resistance compared with cycling. PMID:25317691

  8. Death row inmate characteristics, adjustment, and confinement: a critical review of the literature.

    PubMed

    Cunningham, Mark D; Vigen, Mark P

    2002-01-01

    This article reviews and summarizes research on death row inmates. The contributions and weaknesses of death row demographic data, clinical studies, and research based on institutional records are critiqued. Our analysis shows that death row inmates are overwhelmingly male and disproportionately Southern. Racial representation remains controversial. Frequently death row inmates are intellectually limited and academically deficient. Histories of significant neurological insult are common, as are developmental histories of trauma, family disruption, and substance abuse. Rates of psychological disorder among death row inmates are high, with conditions of confinement appearing to precipitate or aggravate these disorders. Contrary to expectation, the extant research indicates that the majority of death row inmates do not exhibit violence in prison even in more open institutional settings. These findings have implications for forensic mental health sentencing evaluations, competent attorney representation, provision of mental health services, racial disparity in death sentences, death row security and confinement policies, and moral culpability considerations. Future research directions on death row populations are suggested. PMID:11979498

  9. Reconfigurable ternary optical processor based on row operation unit

    NASA Astrophysics Data System (ADS)

    Kai, SONG; LiPing, YAN

    2015-09-01

    In order to eliminate the difference between the data bits and the pixel bits of the processors in the logic operation of Ternary Optical Computer (TOC), and to make the reconfiguration of the processors more convenient and efficient, while extending the research ideas of TOC, the paper presents a new typical optical component, which is row operation unit (ROU). The features, circuit implementations, and commands for the reconfiguration of ROU are also discussed in detail. On this basis, the reconfigurable ternary optical processor (RTOP) was designed and achieved, which reduces the complexity of the processor management software. Finally, the experiments of reconfigurable ROU are performed, which shows that the principles of RTOP are correct, and all 81 commands for the reconfiguration are effective. Each of the two-input, tri-valued logic operations with thousands of data bits can be concurrently achieved in RTOP.

  10. Design and testing of a tandem row pump inducer

    NASA Technical Reports Server (NTRS)

    Etter, R. J.

    1974-01-01

    The design and testing of a tandem row pump inducer having a supercavitating first stage with a 0.60 hub ratio is presented. The second stage tested was a helical impeller with a 0.70 hub ratio. A cubic arc transition was utilized to accomplish the hub change. The first stage had two blades and the free-vortex design approach was empirically modified based on previous experience. The recommended second stage design having four blades and using cambered blade section is presented but the model was not built or tested. The more simple helix was built instead to reduce cost. Data taken included head generation, cavitation observations and unsteady head fluctuations over the 0-100Hz range.

  11. Deterministic blade row interactions in a centrifugal compressor stage

    NASA Technical Reports Server (NTRS)

    Kirtley, K. R.; Beach, T. A.

    1991-01-01

    The three-dimensional viscous flow in a low speed centrifugal compressor stage is simulated using an average passage Navier-Stokes analysis. The impeller discharge flow is of the jet/wake type with low momentum fluid in the shroud-pressure side corner coincident with the tip leakage vortex. This nonuniformity introduces periodic unsteadiness in the vane frame of reference. The effect of such deterministic unsteadiness on the time-mean is included in the analysis through the average passage stress, which allows the analysis of blade row interactions. The magnitude of the divergence of the deterministic unsteady stress is of the order of the divergence of the Reynolds stress over most of the span, from the impeller trailing edge to the vane throat. Although the potential effects on the blade trailing edge from the diffuser vane are small, strong secondary flows generated by the impeller degrade the performance of the diffuser vanes.

  12. Developmental changing in the form and function of rowing hydromedusae

    NASA Astrophysics Data System (ADS)

    Colin, S. P.; Weston, J.; Costello, J. H.; Dabiri, J. O.

    2007-12-01

    Among medusan lineages bell morphology and propulsion appear to be interdependent traits. In general, taxa that possess large oblate bells swim via rowing propulsion and taxa with small prolate bells swim via jet propulsion. However, hydromedusae from the order, Leptomedusae, experience large changes in bell size and shape throughout their development, metamorphosing from small prolate juveniles into large oblate adults. To examine how propulsion changes throughout the development of leptomedusae, we investigated the fluid interactions and swimming characteristics of two leptomedusan species, Aequorea victorea and Eutonina indicans, throughout their development. As expected, these species start off as small prolate juveniles (< 2 mm diameter) and develop into large oblate adults (> 1.5 cm diameter). In addition to changes in morphology, we observed changes in Reynolds number, wake structure, propulsion and swimming kinematics. These changes were consistent with the previously described relationship between bell morphology and function.

  13. Energies of the first row atoms from quantum Monte Carlo.

    PubMed

    Brown, M D; Trail, J R; Ríos, P López; Needs, R J

    2007-06-14

    All-electron variational and diffusion quantum Monte Carlo calculations of the ground state energies of the first row atoms (from Li to Ne) are reported. The authors use trial wave functions of four types: single-determinant Slater-Jastrow wave functions, multideterminant Slater-Jastrow wave functions, single-determinant Slater-Jastrow wave functions with backflow transformations, and multideterminant Slater-Jastrow wave functions with backflow transformations. At the diffusion quantum Monte Carlo level and using their multideterminant Slater-Jastrow wave functions with backflow transformations, they recover 99% or more of the correlation energies for Li, Be, B, C, N, and Ne, 97% for O, and 98% for F. PMID:17581047

  14. Stereological estimation of left-ventricular volumetric and functional parameters from multidetector-row computed tomography data.

    PubMed

    Mazonakis, Michalis; Pagonidis, Konstantin; Schlosser, Thomas; Hunold, Peter; Damilakis, John; Barkhausen, Jörg; Gourtsoyiannis, Nicholas

    2008-07-01

    This study aims to optimize the stereological method for estimating left-ventricular (LV) parameters from retrospectively electrocardiography-gated 16-row MDCT and to compare stereological estimations with those by MRI. MDCT was performed in 17 consecutive patients with known or suspected coronary disease. Stereological measurements based on point counting were optimized by determining the appropriate distance between grid points. LV parameters were evaluated by standard CT analysis using a semi-automatic segmentation method. Two independent observers evaluated the reproducibility of the stereological method. End-diastolic volume (EDV) and end-systolic volume (ESV) estimations with a coefficient of error below 5% were obtained in a mean time of 2.3 +/- 0.5 min with a point spacing of 25 and 15 pixels, respectively. The intra- and interobserver variability for estimating LV parameters was 2.6-4.4 and 4.9-8.2%, respectively. MRI estimations were highly correlated with those by standard CT analysis (R > 0.82) and stereology (R > 0.84). Stereological method significantly overestimated EDV and ESV compared to MRI (EDV: P = 0.0011; ESV: P = 0.0013), whereas for stroke volume (SV) and ejection fraction (EF), no difference was observed (P > 0.05). For standard CT analysis and MRI, significant differences were found except for SV and EF (EDV: P = 0.0008; ESV: P = 0.0004; EF: P = 0.051; SV: P = 0.064). The time-efficient optimized stereological method enables the reproducible evaluation of LV function from MDCT. PMID:18351349

  15. Transfer of Complex Skill Learning from Virtual to Real Rowing

    PubMed Central

    Rauter, Georg; Sigrist, Roland; Koch, Claudio; Crivelli, Francesco; van Raai, Mark; Riener, Robert; Wolf, Peter

    2013-01-01

    Simulators are commonly used to train complex tasks. In particular, simulators are applied to train dangerous tasks, to save costs, and to investigate the impact of different factors on task performance. However, in most cases, the transfer of simulator training to the real task has not been investigated. Without a proof for successful skill transfer, simulators might not be helpful at all or even counter-productive for learning the real task. In this paper, the skill transfer of complex technical aspects trained on a scull rowing simulator to sculling on water was investigated. We assume if a simulator provides high fidelity rendering of the interactions with the environment even without augmented feedback, training on such a realistic simulator would allow similar skill gains as training in the real environment. These learned skills were expected to transfer to the real environment. Two groups of four recreational rowers participated. One group trained on water, the other group trained on a simulator. Within two weeks, both groups performed four training sessions with the same licensed rowing trainer. The development in performance was assessed by quantitative biomechanical performance measures and by a qualitative video evaluation of an independent, blinded trainer. In general, both groups could improve their performance on water. The used biomechanical measures seem to allow only a limited insight into the rowers' development, while the independent trainer could also rate the rowers' overall impression. The simulator quality and naturalism was confirmed by the participants in a questionnaire. In conclusion, realistic simulator training fostered skill gains to a similar extent as training in the real environment and enabled skill transfer to the real environment. In combination with augmented feedback, simulator training can be further exploited to foster motor learning even to a higher extent, which is subject to future work. PMID:24376518

  16. Transfer of complex skill learning from virtual to real rowing.

    PubMed

    Rauter, Georg; Sigrist, Roland; Koch, Claudio; Crivelli, Francesco; van Raai, Mark; Riener, Robert; Wolf, Peter

    2013-01-01

    Simulators are commonly used to train complex tasks. In particular, simulators are applied to train dangerous tasks, to save costs, and to investigate the impact of different factors on task performance. However, in most cases, the transfer of simulator training to the real task has not been investigated. Without a proof for successful skill transfer, simulators might not be helpful at all or even counter-productive for learning the real task. In this paper, the skill transfer of complex technical aspects trained on a scull rowing simulator to sculling on water was investigated. We assume if a simulator provides high fidelity rendering of the interactions with the environment even without augmented feedback, training on such a realistic simulator would allow similar skill gains as training in the real environment. These learned skills were expected to transfer to the real environment. Two groups of four recreational rowers participated. One group trained on water, the other group trained on a simulator. Within two weeks, both groups performed four training sessions with the same licensed rowing trainer. The development in performance was assessed by quantitative biomechanical performance measures and by a qualitative video evaluation of an independent, blinded trainer. In general, both groups could improve their performance on water. The used biomechanical measures seem to allow only a limited insight into the rowers' development, while the independent trainer could also rate the rowers' overall impression. The simulator quality and naturalism was confirmed by the participants in a questionnaire. In conclusion, realistic simulator training fostered skill gains to a similar extent as training in the real environment and enabled skill transfer to the real environment. In combination with augmented feedback, simulator training can be further exploited to foster motor learning even to a higher extent, which is subject to future work. PMID:24376518

  17. Significance of agricultural row structure on the microwave emissivity of soils

    NASA Technical Reports Server (NTRS)

    Promes, P. M.; Jackson, T. J.; O'Neill, P. E.

    1987-01-01

    A series of field experiments was carried out to extend the data base available for verifying agricultural row effect models of emissivity. The row effects model was used to simulate a data base from which an algorithm could be developed to account for row effects when the scene dielectric constant and small-scale roughness are unknown. One objective of the study was to quantify the significance of row structure and to develop a practical procedure for removing the effects of periodic row structure on the microwave emissivity of a soil in order to use the emissivity values to estimate the soil moisture. A second objective was to expand the data set available for model verification through field observations using a truck-mounted 1.4-GHz microwave radiometer.

  18. Positive ions of the first- and second-row transition metal hydrides

    NASA Technical Reports Server (NTRS)

    Pettersson, Lars G. M.; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Partridge, Harry

    1987-01-01

    Theoretical dissociation energies for the first- and second-row transition metal hydride positive ions are critically compared against recent experimental values obtained from ion beam reactive scattering methods. Theoretical spectroscopic parameters and dipole moments are presented for the ground and several low-lying excited states. The calculations employ large Gaussian basis sets and account for electron correlation using the single-reference single- and double-excitation configuration interaction and coupled-pair-functional methods. The Darwin and mass-velocity contributions to the relativistic energy are included in the all-electron calculations on the first-row systems using first-order perturbation theory, and in the second-row systems using the Hay and Wadt relativistic effective core potentials. The theoretical D(0) values for the second-row transition metal hydride positive ions should provide a critical measure of the experimental values, which are not as refined as many of those in the first transition row.

  19. Activation of Spinal Stabilizers and Shoulder Complex Muscles During an Inverted Row Using a Portable Pull-up Device and Body Weight Resistance.

    PubMed

    Youdas, James W; Keith, Julianne M; Nonn, Danielle E; Squires, Adam C; Hollman, John H

    2016-07-01

    Youdas, JW, Keith, JM, Nonn, DE, Squires, AC, and Hollman, JH. Activation of spinal stabilizers and shoulder complex muscles during an inverted row using a portable pull-up device and body weight resistance. J Strength Cond Res 30(7): 1933-1941, 2016-We recorded muscle activation normalized to a maximum voluntary isometric contraction (% MVIC) during an inverted body weight row using a commercially available portable pull-up device. Surface electromyographic (EMG) analysis was conducted on 13 male and 13 female subjects performing 4 inverted row exercises: (a) pronated grip both feet weight-bearing (WB); (b) supinated grip both feet WB; (c) pronated grip one leg WB; and (d) supinated grip single-leg WB. Nine muscles were analyzed: (a) posterior deltoid (PD), (b) latissimus dorsi (LD), (c) biceps brachii (BB), (d) lower trapezius (LT), (e) upper trapezius (UT), (f) lumbar multifidus (LM), (g) middle trapezius (MT), (h) lumbar thoracis (LTh), and (i) rectus abdominis (RA). Normalized peak EMG activity was examined separately for each muscle with 9 repeated measures analysis of variance (ANOVA) at α = 0.05. Post hoc comparisons of EMG activation across exercises for statistically significant ANOVAs were conducted with Bonferroni corrections for multiple comparisons. We observed statistically significant differences in EMG activation of the LD between supinated and pronated double-leg WB (p = 0.001) condition. Additionally, we found statistical significance in the UT between pronated and supinated single-leg WB (p = 0.007). No statistically significant differences in muscle activation existed between single- and double-leg WB in any muscles. Four muscles (BB, LD, LT, and PD) demonstrated very high (>61% MVIC) EMG activation during all 4 exercise conditions. Three muscles (UT, MT, and LM) demonstrated high (41-60% MVIC) activation, whereas 2 muscles (LTh and RA) demonstrated moderate (21-40% MVIC) activation. Four inverted row exercises activated the LD, UT, MT, LT

  20. A High-Resolution Imaging Technique using a Whole-body, Research Photon Counting Detector CT System

    PubMed Central

    Leng, S.; Yu, Z.; Halaweish, A.; Kappler, S.; Hahn, K.; Henning, A.; Li, Z.; Lane, J.; Levin, D. L.; Jorgensen, S.; Ritman, E.; McCollough, C.

    2016-01-01

    A high-resolution (HR) data collection mode has been introduced to the whole-body, research photon-counting-detector CT system installed in our laboratory. In this mode, 64 rows of 0.45 mm × 0.45 mm detectors pixels were used, which corresponded to a pixel size of 0.225 mm × 0.225 mm at the iso-center. Spatial resolution of this HR mode was quantified by measuring the MTF from a scan of a 50 micron wire phantom. An anthropomorphic lung phantom, cadaveric swine lung, temporal bone and heart specimens were scanned using the HR mode, and image quality was subjectively assessed by two experienced radiologists. Comparison of the HR mode images against their energy integrating system (EID) equivalents using comb filters was also performed. High spatial resolution of the HR mode was evidenced by the MTF measurement, with 15 lp/cm and 20 lp/cm at 10% and 2% MTF. Images from anthropomorphic phantom and cadaveric specimens showed clear delineation of small structures, such as lung vessels, lung nodules, temporal bone structures, and coronary arteries. Temporal bone images showed critical anatomy (i.e. stapes superstructure) that was clearly visible in the PCD system but hardly visible with the EID system. These results demonstrated the potential application of this imaging mode in lung, temporal bone, and vascular imaging. Other clinical applications that require high spatial resolution, such as musculoskeletal imaging, may also benefit from this high resolution mode. PMID:27330238