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Sample records for row ct comparison

  1. Coronary artery bypass graft flow: qualitative evaluation with cine single-detector row CT and comparison with findings at angiography.

    PubMed

    Tello, Richard; Hartnell, George G; Costello, Philip; Ecker, Christian P

    2002-09-01

    A four-point ordinal-scale qualitative flow index was used for assessment of patency of 75 coronary artery bypass grafts in 26 patients examined with spiral computed tomography (CT). CT findings were compared with selective graft angiographic findings. Of 54 open grafts, 52 were patent at initial selective graft angiography and 50 were patent at spiral CT; accuracy rates were 97% (73 of 75) and 95% (71 of 75), respectively. Spiral CT flow index agreed with angiographically determined flow in 85% (95% CI: 0.77, 0.93) of grafts. The kappa statistic demonstrated very good to excellent intermodality (0.75) and interobserver (0.89) agreement. Spiral CT may be a feasible means of assessing quality of flow in bypass grafts. PMID:12202732

  2. First-pass perfusion imaging of solitary pulmonary nodules with 64-detector row CT: comparison of perfusion parameters of malignant and benign lesions.

    PubMed

    Li, Y; Yang, Z-G; Chen, T-W; Yu, J-Q; Sun, J-Y; Chen, H-J

    2010-09-01

    The purpose of this study was to determine the usefulness of first-pass whole nodule perfusion imaging in the differentiation of benign and malignant solitary pulmonary nodules (SPNs). 77 patients with non-calcified SPNs (46 malignant, 22 benign and 9 active inflammatory) underwent first-pass perfusion imaging with a 64-detector row CT scanner. Perfusion, peak enhancement intensity (PEI), time to peak (TTP) and blood volume (BV) were measured and statistically compared among different groups. Mean perfusion, PEI and BV for benign SPNs were significantly lower than those for malignant nodules (p<0.05) and active infections (p<0.05), but the differences were not statistically significant between malignant tumours and active infections (p>0.05). Receiver operating characteristic (ROC) curve analysis showed that SPNs with perfusion greater than 30.6 ml min(-1) ml(-1), PEI higher than 23.3 HU or BV larger than 12.2 ml per 100 g were more likely to be malignant. In conclusion, first-pass perfusion imaging with 64-detector row CT is a feasible way of assessing whole nodule perfusion and helpful in differentiating benign from malignant SPNs.

  3. Intercostal Artery Supplying Hepatocellular Carcinoma: Demonstration of a Tumor Feeder by C-arm CT and Multidetector Row CT

    SciTech Connect

    Kim, Hyo-Cheol Chung, Jin Wook; Lee, In Joon; An, Sangbu; Seong, Nak Jong; Son, Kyu Ri; Jae, Hwan Jun; Park, Jae Hyung

    2011-02-15

    This study was designed to describe tumor feeders from the intercostal artery supplying hepatocellular carcinoma (HCC) on C-arm CT and multidetector row CT. From March 2008 to May 2009, C-arm CT of the intercostal artery was prospectively performed in 24 HCC patients. Two interventional radiologists, who performed C-arm CT, evaluated tumor feeders on C-arm CT and multidetector row CT scans by consensus. In total, 35 intercostal arteries were examined by C-arm CT. All tumor feeders except one showed a sharp upward turn at or near the costochondral junction. On axial C-arm CT images, all tumor feeders were observed as an enhancing dot in the upper intercostal space along the diaphragm. On multidetector CT scans, 17 tumor feeders were observed and 18 were not. Tumor feeders from the intercostal artery are observed as an enhancing dot along the diaphragm on C-arm CT and can be seen on multidetector row CT in approximately half of patients.

  4. Three-dimensional multi-detector row CT portal venography in the evaluation of portosystemic collateral vessels in liver cirrhosis.

    PubMed

    Kang, Heoung Keun; Jeong, Yong Yeon; Choi, Jun Ho; Choi, Song; Chung, Tae Woong; Seo, Jeong Jin; Kim, Jae Kyu; Yoon, Woong; Park, Jin Gyoon

    2002-01-01

    Multi-detector row computed tomography (CT) offers distinct advantages over traditional spiral CT. Multi-detector row CT scanners are faster and allow thinner collimation than single-detector row spiral CT scanners. The use of multi-detector row CT combined with postprocessing of the imaging data with a variety of three-dimensional reformatting techniques (eg, maximum intensity projection, shaded surface display, volume rendering) allows creation of vascular maps whose quality equals or exceeds that of maps created at classic angiography for many applications. Three-dimensional multi-detector row CT portal venography can help determine the extent and location of portosystemic collateral vessels (eg, left gastric vein, short gastric vein, esophageal and paraesophageal varices, splenorenal and gastrorenal shunts, paraumbilical and abdominal wall veins) in patients with liver cirrhosis and is probably the optimal imaging technique in this setting.

  5. Secondary aortoenteric fistula: active bleeding detected with multi-detector-row CT.

    PubMed

    Roos, Justus E; Willmann, Jürgen K; Hilfiker, Paul R

    2002-12-01

    We report a case of active bleeding of a secondary aortoenteric fistula (SAEF), in which CT angiography with multi-detector-row CT (MDCT) was finally diagnostic after negative catheter angiography and unsatisfactory endoscopy. The MDCT angiography clearly demonstrated the fistulous tract between the abdominal aortic graft and the duodenum. The dynamic process of bleeding was confirmed as a net increase of contrast agent accumulation in the duodenum through different phases. The MDCT angiography with its excellent 3D image quality is therefore a valuable method in the assessment of active SAEF bleeding. PMID:12522640

  6. 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

  7. 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.

  8. 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...

  9. [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

  10. Diagnostic applications of cardiac multislice CT with sixteen-row scanner: state of the art.

    PubMed

    Tognini, Giuseppe; Arisi, Arianna; Ferrozzi, Francesco; De Blasi, Mario; De Filippo, Massimo; Paoli, Giorgia; Patti, Arianna; Bnà, Claudio; Zompatori, Maurizio; Ardissimo, Diego; Gherli, Tiziano

    2004-01-01

    Coronary angiography is nowadays the diagnostic standard in the evaluation of coronary artery anatomy, in the identification of stenoses and in the follow-up of revascularization procedures (PTCA-stenting, bypass). The limitations of such technique in terms of invasivity and high cost has targeted research efforts towards the development of non invasive diagnostic tools. Technological evolution in the field of helical CT has provided 2, 4, 8 and 16 detector-row multislice scanners characterized by progressive improvements in terms of spatial and temporal resolution that have made them increasingly suitable for the analysis of moving structures with high quality anatomic detail. The main cardiologic applications of multislice CT include coronary calcium scoring, the evaluation of coronary vascular anatomy and disease, follow-up of revascularization procedures (stenting, bypass), and the evaluation of cardiac walls and chambers. The aim of this paper is to describe the applications of sixteen detector-row multisclice CT in non invasive evaluation of cardiac and coronary diseases.

  11. [Motion analysis of target in stereotactic radiotherapy of lung tumors using 320-row multidetector CT].

    PubMed

    Imae, Toshikazu; Haga, Akihiro; Nakagawa, Keiichi; Ino, Kenji; Tanaka, Kenichirou; Okano, Yukari; Sasaki, Katsutake; Saegusa, Shigeki; Shiraki, Takashi; Oritate, Takashi; Yano, Keiichi; Shinohara, Hiroyuki

    2011-01-01

    Multi-detector computed tomography (MDCT) has rapidly evolved and is increasingly used for treatment simulation of thoracic and abdominal radiotherapy. A 320-detector row CT scanner has recently become available that allows axial volumetric scanning of a 16-cm-long range in a patient without table movement. Current radiotherapy techniques require a generous margin around the presumed gross tumor volume (GTV) to account for uncertainties such as tumor motion and set up error. Motion analysis is useful to evaluate the internal margin of a moving target due to respiration and to improve therapeutic precision. The purpose of this study is to propose a method using phase-only correlation to automatically detect the target and to assess the motion of the target in numerical phantoms and patients. Free-breathing scans using 320-detector row CT were acquired for 4 patients with lung tumor(s). The proposed method was feasible for motion analysis of all numerical phantoms and patients. The results reproduced the facts that the motion of tumors in the patients varied in orbits during the respiratory cycle and exhibited hysteresis. The maximum distance between peak exhalation and inhalation increased as the tumors approached the diaphragm. The proposed method detected the three-dimensional position of the targets automatically and analyzed the trajectories. The tumor motion due to respiration differed by region and was greatest for the lower lobe. PMID:21471676

  12. 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.

  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. 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.

  15. Benefits of contrast-enhanced multidetector row CT colonography for preoperative staging in colorectal cancer patients

    NASA Astrophysics Data System (ADS)

    Iinuma, Gen; Moriyama, Noriyuki; Satake, Mitso; Miyakawa, Kunihisa; Muramatsu, Yukio; Tateishi, Ukihide; Akasu, Takayuki; Otake, Yousuke; Fujii, Takahiro; Kobayashi, Toshiaki

    2003-05-01

    Recently, CT colonography has been recognized as an effective option for evaluating colorectal polyps in the USA. We have applied this technique to preoperative staging of colorectal cancer patients with a contrast-enhanced multi-detector row CT (MDCT). The use of manipulated multi-planar reconstruction (MPR) views in contrast-enhanced MDCT colonography proved advantageous for detecting lymph node metastases. Furthermore, 3-dimensional (3D) endoluminal images with Hansfield-transparency settings allowed vascular views of the colorectal wall for identification of invasive colorectal cancers. Using endoluminal images, increase in flow and pooling of blood related to angiogenesis of invasive cancer could be demonstrated, not only in the lymph nodes but also in the colorectal wall. Both MPR views and 3D endoluminal images can be acquired from the same 3D volumetric data generated by helical scanning in MDCT colonography, and both have great potential as modalities for computer-aided diagnosis (CAD) using blood flow information. Therefore the use of CAD can be expected to improve radiologists' diagnostic performance with regard to colorectal cancer.

  16. 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.

  17. 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

  18. [Characteristics of pneumoconiosis on multi-detector row CT and its' anatomic-pathologic basis].

    PubMed

    Feng, Yuanchun; Yang, Zhigang; Li, Yuan; Chen, Tianwu; Wang, Qiling; Deng, Wen

    2011-04-01

    In order to investigate the fine distinction of the tomographic images and the dominant anatomic distributions, we carefully reviewed and analyzed the features and predominant anatomic distribution of forty-nine pneumoconiosis patients with confirmed diagnosis on multi-detector row CT (MDCT). It was found that the round and small opacity p and irregular small opacity were mostly shown in the MDCT features of pneumoconiosis, while the large opacity and progressive massive fibrosis (PMF) were less frequently depicted in the MDCT. Distributions of round and small opacity and irregular small opacity in the six lung lobes were significantly different (P < 0.01). The most common p opacity was significantly seen in the upper and lower left lungs as well as in the upper right lung's opacity was in the upper left lung as well as lower left and right lungs. The large opacity commonly distributed in upper left and right lungs, while the PMF was often shown in both of two lungs. The results demonstrated that the MDCT could be an effective modality for detecting tiny lesions and anatomic distribution of pneumoconiosis, and it would be helpful for early diagnosis and accurate staging of the pneumoconiosis disease.

  19. [Peripheral lung adenocarcinoma versus squamous cell carcinoma: evaluation with first-pass perfusion imaging using 64-detector row CT].

    PubMed

    Li, Yuan; Yang, Zhigang; Chen, Tianwu; Yu, Jianqun; Deng, Yuping; Li, Zhenlin

    2009-04-01

    The aim of this study was to elucidate the characteristics of time attenuation curve and CT perfusion parameters for pulmonary adenocarcinomas and squamous cell carcinomas. 58 cases of pulmonary adenocarcinomas and 27 cases of squamous cell carcinomas underwent first pass CT perfusion imaging with 64-row MDCT. Data were analyzed using commercial software to generate time attenuation curve (TAC) and CT perfusion parameters, including perfusion, peak enhanced (PE), time to peak (TTP), and blood volume (BV). For TAC, there were 36.2% of type I and 63.8% of type II in adenocarcinomas, while there were 22.2% of type I and 77.8% of type II in squamous cell carcinomas. There was not significant difference (P>0.05). Perfusion, PE, TTP and BV of adenocarcinomas were 63.2 +/- 45.4 ml x min(-1) x ml(-1), 60.2 +/- 46.6 Hu, 34.8 +/- 10.2 s and 34.3 +/- 23.6 ml x 100 g(-1), respectively, while 54.3 +/- 50.2 ml x min(-1) x ml(-1), 48.5 +/- 34.9 Hu, 36.1 +/- 11.2 s and 27.6 +/- 21.7 ml x 100 g(-1), for squamous cell carcinoma, respectively. No significant differences were found between groups (P>0.05). No significant differences in TAC and CT perfusion parameters were found between adenocarcinomas and squamous cell carcinomas.

  20. The role of multidetector-row CT in the diagnosis, classification and management of acute aortic syndrome

    PubMed Central

    Brown, I W; Peebles, C R; Harden, S P; Shambrook, J S

    2014-01-01

    The term “acute aortic syndrome” (AAS) encompasses several non-traumatic life-threatening pathologies of the thoracic aorta presenting in patients with a similar clinical profile. These include aortic dissection, intramural haematoma and penetrating atherosclerotic ulcers. These different pathological entities can be indistinguishable on clinical grounds alone and may be confused with other causes of chest pain, including myocardial infarction. Multidetector-row CT (MDCT) is the current modality of choice for imaging AAS with a sensitivity and specificity approaching 100%. Early diagnosis and accurate radiological classification is associated with improved clinical outcomes in AAS. We review the characteristic radiological features of the different pathologies that encompass AAS and highlight the vital role of MDCT in determining the management of these life-threatening conditions. PMID:25083552

  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. Value of Virtual Colonoscopy with 64 Row CT in Evaluation of Colorectal Cancer

    PubMed Central

    Zaleska-Dorobisz, Urszula; Łasecki, Mateusz; Nienartowicz, Ewa; Pelak, Joanna; Słonina, Joanna; Olchowy, Cyprian; Ścieżka, Marek; Sąsiadek, Marek

    2014-01-01

    Summary Background Virtual colonoscopy (VC) enables three-dimensional view of walls and internal lumen of the colon as a result of reconstruction of multislice CT images. The role of VC in diagnosis of the colon abnormalities systematically increases, and in many medical centers all over the world is carried out as a screening test of patients with high risk of colorectal cancer. Material/Methods We analyzed results of virtual colonoscopy of 360 patients with clinical suspicion of colorectal cancer. Sensitivity and specificity of CT colonoscopy for detection of colon cancers and polyps were assessed. Results Results of our research have shown high diagnostic efficiency of CT colonoscopy in detection of focal lesions in large intestine of 10 mm or more diameter. Sensitivity was 85.7%, specificity 89.2%. Conclusions Virtual colonoscopy is noninvasive and well tolerated by patients imaging method, which permits for early detection of the large intestine lesions with specificity and sensitivity similar to classical colonoscopy in screening exams in patients suspected for colorectal cancer. Good preparation of the patients for the examination is very important for proper diagnosis and interpretation of this imaginge procedure. PMID:25302086

  3. 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

  4. Radiation dose assessment in a 320-detector-row CT scanner used in cardiac imaging

    SciTech Connect

    Goma, Carles; Ruiz, Agustin; Jornet, Nuria; Latorre, Artur; Pallerol, Rosa M.; Carrasco, Pablo; Eudaldo, Teresa; Ribas, Montserrat

    2011-03-15

    Purpose: In the present era of cone-beam CT scanners, the use of the standardized CTDI{sub 100} as a surrogate of the idealized CTDI is strongly discouraged and, consequently, so should be the use of the dose-length product (DLP) as an estimate of the total energy imparted to the patient. However, the DLP is still widely used as a reference quantity to normalize the effective dose for a given scan protocol mainly because the CTDI{sub 100} is an easy-to-measure quantity. The aim of this article is therefore to describe a method for radiation dose assessment in large cone-beam single axial scans, which leads to a straightforward estimation of the total energy imparted to the patient. The authors developed a method accessible to all medical physicists and easy to implement in clinical practice in an attempt to update the bridge between CT dosimetry and the estimation of the effective dose. Methods: The authors used commercially available material and a simple mathematical model. The method described herein is based on the dosimetry paradigm introduced by the AAPM Task Group 111. It consists of measuring the dose profiles at the center and the periphery of a long body phantom with a commercial solid-state detector. A weighted dose profile is then calculated from these measurements. To calculate the CT dosimetric quantities analytically, a Gaussian function was fitted to the dose profile data. Furthermore, the Gaussian model has the power to condense the z-axis information of the dose profile in two parameters: The single-scan central dose, f(0), and the width of the profile, {sigma}. To check the energy dependence of the solid-state detector, the authors compared the dose profiles to measurements made with a small volume ion chamber. To validate the overall method, the authors compared the CTDI{sub 100} calculated analytically to the measurement made with a 100 mm pencil ion chamber. Results: For the central and weighted dose profiles, the authors found a good

  5. Technical note: Electrocardiogram electrode repositioning for 320-row coronary CT angiography in patients with regular and recurrent premature ventricular contractions.

    PubMed

    Kondo, Takeshi; Matsutani, Hideyuki; Groarke, John; Takamura, Kazuhisa; Fujimoto, Shinichiro; Rybicki, Frank J; Kumamaru, Kanako K

    2014-01-01

    Arrhythmias can compromise image quality and increase radiation exposure during coronary CT angiography (CTA). However, premature ventricular contractions (PVCs) can occur in a predictable recurrent and regular pattern (ie, bigeminy, trigeminy, quadrigeminy) with post-PVC compensatory pauses. Electrocardiographic (ECG) electrode repositioning can achieve relative amplification of the R waves of PVCs compared with R waves of sinus beats. This technical note describes how simple ECG electrode repositioning, combined with an absolute-delay strategy, facilitated selective R waves of PVC ECG triggering of image acquisition in 6 patients with PVC bigeminy or quadrigeminy at the time of 320-row coronary CTA. All 6 studies were single heartbeat acquisition scans with excellent image quality and a median effective radiation dose of 2.9 mSv (interquartile range, 2.1-3.8 mSv). Standard ECG electrode positions used for 2 patients with PVC bigeminy undergoing coronary CTA were associated with an acquisition over 2 heartbeats and effective radiation doses of 6.8 and 10.3 mSv, respectively. In conclusion, ECG electrode repositioning combined with an absolute-delay strategy for regularly recurring PVCs, such as ventricular bigeminy, facilitates high image quality and lower radiation dose during coronary CTA. This simple and straightforward technique can be considered for all patients with regular and recurrent PVCs undergoing coronary CTA.

  6. Quantitative colorectal cancer perfusion measurement by multidetector-row CT: does greater tumour coverage improve measurement reproducibility?

    PubMed

    Goh, V; Halligan, S; Gartner, L; Bassett, P; Bartram, C I

    2006-07-01

    The purpose of this study was to determine if greater z-axis tumour coverage improves the reproducibility of quantitative colorectal cancer perfusion measurements using CT. A 65 s perfusion study was acquired following intravenous contrast administration in 10 patients with proven colorectal cancer using a four-detector row scanner. This was repeated within 48 h using identical technical parameters to allow reproducibility assessment. Quantitative tumour blood volume, blood flow, mean transit time and permeability measurements were determined using commercially available software (Perfusion 3.0; GE Healthcare, Waukesha, WI) for data obtained from a 5 mm z-axis tumour coverage, and from a 20 mm z-axis tumour coverage. Measurement reproducibility was assessed using Bland-Altman statistics, for a 5 mm z-axis tumour coverage, and 20 mm z-axis tumour coverage, respectively. The mean difference (95% limits of agreement) for blood volume, blood flow, mean transit time and permeability were 0.04 (-2.50 to +2.43) ml/100 g tissue; +8.80 (-50.5 to +68.0) ml/100 g tissue/min; -0.99 (-8.19 to +6.20) seconds; and +1.20 (-5.42 to +7.83) ml/100 g tissue/min, respectively, for a 5 mm coverage, and -0.04 (-2.61 to +2.53) ml/100 g tissue; +7.40 (-50.3 to +65.0) ml/100 g tissue/min; -2.46 (-12.61 to +7.69) seconds; and -0.23 (-8.31 to +7.85) ml/100 g tissue/min, respectively, for a 20 mm coverage, indicating similar levels of agreement. In conclusion, increasing z-axis coverage does not improve reproducibility of quantitative colorectal cancer perfusion measurements.

  7. 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.

  8. Influence of 320-detector-row volume scanning and AAPM report 111 CT dosimetry metrics on size-specific dose estimate: a Monte Carlo study.

    PubMed

    Haba, Tomonobu; Koyama, Shuji; Kinomura, Yutaka; Ida, Yoshihiro; Kobayashi, Masanao

    2016-09-01

    The American Association of Physicists in Medicine (AAPM) task group 204 has recommended the use of size-dependent conversion factors to calculate size-specific dose estimate (SSDE) values from volume computed tomography dose index (CTDIvol) values. However, these conversion factors do not consider the effects of 320-detector-row volume computed tomography (CT) examinations or the new CT dosimetry metrics proposed by AAPM task group 111. This study aims to investigate the influence of these examinations and metrics on the conversion factors reported by AAPM task group 204, using Monte Carlo simulations. Simulations were performed modelling a Toshiba Aquilion ONE CT scanner, in order to compute dose values in water for cylindrical phantoms with 8-40-cm diameters at 2-cm intervals for each scanning parameter (tube voltage, bow-tie filter, longitudinal beam width). Then, the conversion factors were obtained by applying exponential regression analysis between the dose values for a given phantom diameter and the phantom diameter combined with various scanning parameters. The conversion factors for each scanning method (helical, axial, or volume scanning) and CT dosimetry method (i.e., the CTDI100 method or the AAPM task group 111 method) were in agreement with those reported by AAPM task group 204, within a percentage error of 14.2 % for phantom diameters ≥11.2 cm. The results obtained in this study indicate that the conversion factors previously presented by AAPM task group 204 can be used to provide appropriate SSDE values for 320-detector-row volume CT examinations and the CT dosimetry metrics proposed by the AAPM task group 111.

  9. Influence of 320-detector-row volume scanning and AAPM report 111 CT dosimetry metrics on size-specific dose estimate: a Monte Carlo study.

    PubMed

    Haba, Tomonobu; Koyama, Shuji; Kinomura, Yutaka; Ida, Yoshihiro; Kobayashi, Masanao

    2016-09-01

    The American Association of Physicists in Medicine (AAPM) task group 204 has recommended the use of size-dependent conversion factors to calculate size-specific dose estimate (SSDE) values from volume computed tomography dose index (CTDIvol) values. However, these conversion factors do not consider the effects of 320-detector-row volume computed tomography (CT) examinations or the new CT dosimetry metrics proposed by AAPM task group 111. This study aims to investigate the influence of these examinations and metrics on the conversion factors reported by AAPM task group 204, using Monte Carlo simulations. Simulations were performed modelling a Toshiba Aquilion ONE CT scanner, in order to compute dose values in water for cylindrical phantoms with 8-40-cm diameters at 2-cm intervals for each scanning parameter (tube voltage, bow-tie filter, longitudinal beam width). Then, the conversion factors were obtained by applying exponential regression analysis between the dose values for a given phantom diameter and the phantom diameter combined with various scanning parameters. The conversion factors for each scanning method (helical, axial, or volume scanning) and CT dosimetry method (i.e., the CTDI100 method or the AAPM task group 111 method) were in agreement with those reported by AAPM task group 204, within a percentage error of 14.2 % for phantom diameters ≥11.2 cm. The results obtained in this study indicate that the conversion factors previously presented by AAPM task group 204 can be used to provide appropriate SSDE values for 320-detector-row volume CT examinations and the CT dosimetry metrics proposed by the AAPM task group 111. PMID:27444155

  10. Correlative Imaging in a Patient with Cystic Thymoma: CT, MR and PET/CT Comparison

    PubMed Central

    Romeo, Valeria; Esposito, Alfredo; Maurea, Simone; Camera, Luigi; Mainenti, Pier Paolo; Palmieri, Giovannella; Buonerba, Carlo; Salvatore, Marco

    2015-01-01

    Summary Background Cystic thymoma is a rare variant of thymic neoplasm characterized by almost complete cystic degeneration with mixed internal structure. We describe a case of a 60 year-old woman with a cystic thymoma studied with advanced tomographic imaging stydies. CT, MRI and PET/CT with 18F-FDG were performed; volumetric CT and MRI images provided better anatomic evaluation for pre-operative assessment, while PET/CT was helpful for lesion characterization based on 18F-FDG uptake. Although imaging studies are mandatory for pre-operative evaluation of cystic thymoma, final diagnosis still remains surgical. Case Report A 60-year-old woman with recent chest pain and no history of previous disease was admitted to our departement to investigate the result of a previous chest X-ray that showed bilateral mediastinal enlargement; for this purpose, enhanced chest CT scan was performed using a 64-rows scanner (Toshiba, Aquilion 64, Japan) before and after intravenous bolus administration of iodinated non ionic contrast agent; CT images demonstrated the presence of a large mediastinal mass (11×8 cm) located in the anterior mediastinum who extended from the anonymous vein to the cardio-phrenic space, compressing the left atrium and causing medium lobe atelectasis; bilateral pleural effusion was also present. Conclusions In conclusion, correlative imaging plays a foundamental role for the diagnostic evaluation of patient with cystic thymoma. In particular, volumetric CT and MRI studies can provide better anatomic informations regarding internal structure and local tumor spread for pre-operative assessment. Conversely, metabolic imaging using 18F-FDG PET/CT is helpful for lesion characterization differentiating benign from malignant lesion on the basis of intense tracer uptake. The role of PET/MRI is still under investigation. However, final diagnosis still remains surgical even though imaging studies are mandatory for pre-operative patient management. PMID:25593635

  11. A comparison of electromyography and stroke kinematics during ergometer and on-water rowing.

    PubMed

    Fleming, Neil; Donne, Bernard; Mahony, Nicholas

    2014-01-01

    This study assessed muscle recruitment patterns and stroke kinematics during ergometer and on-water rowing to validate the accuracy of rowing ergometry. Male rowers (n = 10; age 21 ± 2 years, height 1.90 ± 0.05 m and body mass 83.3 ± 4.8 kg) performed 3 × 3 min exercise bouts, at heart and stroke rates equivalent to 75, 85 and 95% VO2peak, on both dynamic and stationary rowing ergometers, and on water. During exercise, synchronised data for surface electromyography (EMG) and 2D kinematics were recorded. Overall muscle activity was quantified by the integration of rmsEMG and averaged for each 10% interval of the stroke cycle. Muscle activity significantly increased in rectus femoris (RF) and vastus medialis (VM) (P <0.01), as exercise intensity increased. Comparing EMG data across conditions revealed significantly (P <0.05) greater RF and VM activity during on-water rowing at discrete 10% intervals of stroke cycle. In addition, the drive/recovery ratio was significantly lower during dynamic ergometry compared to on-water (40 ± 1 vs. 44 ± 1% at 95%, P <0.01). Results suggest that significant differences exist while comparing recruitment and kinematic patterns between on-water and ergometer rowing. These differences may be due to altered acceleration and deceleration of moving masses on-ergometer not perfectly simulating the on-water scenario.

  12. 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.

  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. 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

  15. 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.

  16. 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

  17. 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…

  18. CT features and common causes of arc of Riolan expansion: an analysis with 64-detector-row computed tomographic angiography

    PubMed Central

    Xie, Yuanliang; Jin, Chaolin; Zhang, Shutong; Wang, Xiang; Jiang, Yanping

    2015-01-01

    Objective: To study the manifestations of arc of Riolan expansion (ARE) using multi-detector computed tomography angiography (MDCTA). Materials and methods: The manifestations and clinical data of 626 consecutive mesentery CTA images were retrospectively analyzed. The 47 cases with ARE and 47 patients without expansion were involved. The average diameter of arc of Riolan was measured. Two radiologists after reaching consensus analyzed the shapes of mesenteric artery, CT findings and the occurrence and causes of ARE. Results: The mean diameter of arc of Riolan was 1.2 mm, 4.6 mm, 2.5 mm, 2.3 mm, 1.9 mm, 2.5 mm, and 2.0 mm at baseline and following obstruction of superior mesenteric artery (SMA), stenosis of SMA, obstruction of inferior mesenteric artery (IMA), stenosis of IMA, colon cancer, and active ulcerative colitis, respectively. The expansion of arc of Riolan was the most significant following obstruction of SMA. The diameters of arc of Riolan were significantly different between the upward flow group and the downward or the two-way flow groups, and between the colon tumor group and the active ulcerative colitis group. CT findings such as bowel wall thickening, contrast enhancement, intestinal obstruction, marginal artery expansion, lymph node enlargement varied and were help to identify the cause of ARE. Conclusions: ARE often suggests the occurrence of obstructed intestinal feeding artery or intestinal lesions. MDCTA can clearly display the situation of arc of Riolan and collateral circulation, and together with CT symptoms, can guide the selection of diagnosis and treatment schemes in clinic. PMID:26064208

  19. 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

  20. Relationship between beat to beat coronary artery motion and image quality in prospectively ECG-gated two heart beat 320-detector row coronary CT angiography.

    PubMed

    Tomizawa, Nobuo; Komatsu, Shuhei; Akahane, Masaaki; Torigoe, Rumiko; Kiryu, Shigeru; Ohtomo, Kuni

    2012-01-01

    The objective was to investigate the influence of the beat-to-beat movement of the coronary arteries on image quality of multi-segment reconstruction (MSR) images. Although MSR improves temporal resolution, image quality would be degraded by beat-to-beat movement of the coronary arteries. In a retrospectively review, 18 patients (mean age, 67.0 years) who underwent coronary CT angiography using a 320-detector row CT were included. The displacement and diameter of coronary artery segments for each of the identified nine landmarks was recorded. The motion ratio was calculated as the division of displacement by diameter. Image quality (IQ) was graded by a four-point scale. The correlation between MSR IQ score and the motion ratio showed stronger negative correlation than that between MSR IQ score and the displacement (r = -0.54 vs. r = -0.36). The average motion ratio for segments in which half-scan reconstruction (HSR) IQ was better than MSR IQ (29.1%, group A) was higher than that for segments in which MSR IQ was better than HSR IQ (16.0%, group C). The motion ratio in group C was lower than 25%. Difference in IQ scores of the HSR images was more frequent in group A than in the remaining segments in which the motion ratio was lower than 25% (16.7% vs. 66.0%; P < 0.0002). The motion ratio could be a better index than the displacement to evaluate the influence of the motion of coronary arteries on image quality. MSR images would be impaired by a motion ratio larger than 25%. Image impairment of one of the HSR images might also impair MSR images.

  1. A comparison of the bonding in the second-row transition-metal oxides and carbenes

    NASA Astrophysics Data System (ADS)

    Siegbahn, Per E. M.

    1993-01-01

    Calculations including electron correlation of all valence electrons have been performed for the sequence of second-row transition-metal oxides and carbenes. For the atoms to the right the bond strengths of the carbenes and the oxides are similar while for the atoms to the left the oxide bond strengths are much larger. The origin of this difference is the interaction between the oxygen lone pairs and empty 4d orbitals on the metal. With the large donation of electrons from the oxygen lone pair to the metal for the atoms to the left, the bonding can almost be described as triple bond formation for YO, ZrO and NbO. For MoO, where a 4d π orbital is singly occupied on the metal, the bond strength is much smaller than for the oxides to the left. For the metal carbenes two covalent bonds are formed. The ground state spin for the oxides to the right is higher than for the corresponding carbenes, which can be explained by the presence of the π degeneracy for the oxides. The relevance of the present results for the epoxidation and the olefin metathesis reactions are discussed.

  2. 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.

  3. 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

  4. 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.

  5. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities

    PubMed Central

    Weidlich, Georg A.

    2016-01-01

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities—fan beam and cone beam—was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient. PMID:27752404

  6. 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.

  7. Quadriceps tendon rupture: a biomechanical comparison of transosseous equivalent double-row suture anchor versus transosseous tunnel repair.

    PubMed

    Hart, Nathan D; Wallace, Matthew K; Scovell, J Field; Krupp, Ryan J; Cook, Chad; Wyland, Douglas J

    2012-09-01

    Quadriceps rupture off the patella is traditionally repaired by a transosseous tunnel technique, although a single-row suture anchor repair has recently been described. This study biomechanically tested a new transosseous equivalent (TE) double-row suture anchor technique compared with the transosseous repair for quadriceps repair. After simulated quadriceps-patella avulsion in 10 matched cadaveric knees, repairs were completed by either a three tunnel transosseous (TT = 5) or a TE suture anchor (TE = 5) technique. Double-row repairs were done using two 5.5 Bio-Corkscrew FT (fully threaded) (Arthrex, Inc., Naples, FL, USA) and two 3.5 Bio-PushLock anchors (Arthrex, Inc., Naples, FL, USA) with all 10 repairs done with #2 FiberWire suture (Arthrex, Inc., Naples, FL). Cyclic testing from 50 to 250 N for 250 cycles and pull to failure load (1 mm/s) were undertaken. Gap formation and ultimate tensile load (N) were recorded and stiffness data (N/mm) were calculated. Statistical analysis was performed using a Mann-Whitney U test and survival characteristics examined with Kaplan-Meier test. No significant difference was found between the TE and TT groups in stiffness (TE = 134 +/- 15 N/mm, TT = 132 +/- 26 N/mm, p = 0.28). The TE group had significantly less ultimate tensile load (N) compared with the TT group (TE = 447 +/- 86 N, TT = 591 +/- 84 N, p = 0.04), with all failures occurring at the suture eyelets. Although both quadriceps repairs were sufficiently strong, the transosseous repairs were stronger than the TE suture anchor repairs. The repair stiffness and gap formation were similar between the groups.

  8. [Comparison between CT and NMR images. Physical aspects].

    PubMed

    Poretti, G

    1984-10-27

    On the basis of simple physical considerations, parameters influencing the computer tomograph (CT) and nuclear magnetic resonance (NMR) pictures are compared. In the case of the CT, only X-ray tube voltage and radiation intensity (i.e. dose to the patient) can be altered. Changing the X-ray tube voltage alone produces no special diagnostic advantages, unless the method is supplemented, for a specific body region, by separate determination of the "Hounsfield number" in Compton or photoelectric numbers. However, the method is associated with relatively major measurement and evaluation problems. A survey of the principles of the NMR technique is followed by a brief explanation of the so-called "tissue parameters" and "measurement parameters" which influence picture quality in the NMR technique. Despite certain advantages it can scarcely be expected that the NMR technique will replace the CT technique in the next few years: it is very probable, however, that a shift to specific examinations will occur in the case of the latter.

  9. 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.

  10. 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.

  11. 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%.

  12. 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.

  13. Suicide on death row.

    PubMed

    Lester, David; Tartaro, Christine

    2002-09-01

    The suicide rate on death row for the period 1976 through 1999 was found to be high (113 per 100,000 per year), some five times higher than the suicide rate for the male population of the United States. The death row suicide rate was predicted by features of the death row population (negatively with the population on death row) and by social indicators of the society as a whole (negatively with birth and divorce rates and positively with marriage rates).

  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

    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.

  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

    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.

  18. Development of CCD-based optical computed tomography and comparison with single-beam optical CT scanner

    NASA Astrophysics Data System (ADS)

    Chang, Y. J.

    2015-01-01

    This study reports on the development of CCD-based optical computed tomography (CT) CT-s2. A commercially available 10× fast optical computed tomography scanner (OCTOPUSTM-10X, MGS Research, Inc., Madison, CT, USA) was used for comparison. NIPAM polymer gel dosimeter was used to validate the performance of CT-s2. The gamma pass rate can reach 96.00% when using a 3% dose difference and 3 mm dose-to-agreement criteria. The results of CT-s2 are as good as those of the single-beam optical-CT scanner, but the scanning time of CT-s2 is only one-tenth of that of the single-beam optical-CT scanner.

  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. INTERIOR, SOUTH PART, CAMERA FACING SOUTHWEST. DOUBLE ROW OF CENTER ...

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

    INTERIOR, SOUTH PART, CAMERA FACING SOUTHWEST. DOUBLE ROW OF CENTER COLUMNS REFLECTS SOUTH PART'S RE-USE OF ANOTHER BUILDING'S STRUCTURAL FRAME. - New Haven Rail Yard, Work Equipment Shop, Vicinity of Cedar & Lamberton Streets, New Haven, New Haven County, CT

  1. 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

  2. Experimental comparison of empirical material decomposition methods for spectral CT.

    PubMed

    Zimmerman, Kevin C; Schmidt, Taly Gilat

    2015-04-21

    Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, using both simulations and experiments with a photon-counting x-ray detector. Both the neural network and A-table methods demonstrated a similar performance for the simulated data. The neural network had lower standard deviation for nearly all thicknesses of the test materials in the collimated (low scatter) and uncollimated (higher scatter) experimental data. In the experimental study of Teflon thicknesses, non-ideal detector effects demonstrated a potential bias of 11-28%, which was reduced to 0.1-11% using the proposed empirical methods. Overall, the results demonstrated preliminary experimental feasibility of empirical material decomposition for spectral CT using photon-counting detectors.

  3. Experimental comparison of empirical material decomposition methods for spectral CT

    NASA Astrophysics Data System (ADS)

    Zimmerman, Kevin C.; Gilat Schmidt, Taly

    2015-04-01

    Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, using both simulations and experiments with a photon-counting x-ray detector. Both the neural network and A-table methods demonstrated a similar performance for the simulated data. The neural network had lower standard deviation for nearly all thicknesses of the test materials in the collimated (low scatter) and uncollimated (higher scatter) experimental data. In the experimental study of Teflon thicknesses, non-ideal detector effects demonstrated a potential bias of 11-28%, which was reduced to 0.1-11% using the proposed empirical methods. Overall, the results demonstrated preliminary experimental feasibility of empirical material decomposition for spectral CT using photon-counting detectors.

  4. Experimental Comparison of Empirical Material Decomposition Methods for Spectral CT

    PubMed Central

    Zimmerman, Kevin C.; Schmidt, Taly Gilat

    2015-01-01

    Material composition can be estimated from spectral information acquired using photon counting x-ray detectors with pulse height analysis. Non-ideal effects in photon counting x-ray detectors such as charge-sharing, k-escape, and pulse-pileup distort the detected spectrum, which can cause material decomposition errors. This work compared the performance of two empirical decomposition methods: a neural network estimator and a linearized maximum likelihood estimator with correction (A-table method). The two investigated methods differ in how they model the nonlinear relationship between the spectral measurements and material decomposition estimates. The bias and standard deviation of material decomposition estimates were compared for the two methods, using both simulations and experiments with a photon-counting x-ray detector. Both the neural network and A-table methods demonstrated similar performance for the simulated data. The neural network had lower standard deviation for nearly all thicknesses of the test materials in the collimated (low scatter) and uncollimated (higher scatter) experimental data. In the experimental study of Teflon thicknesses, non-ideal detector effects demonstrated a potential bias of 11–28%, which was reduced to 0.1–11% using the proposed empirical methods. Overall, the results demonstrated preliminary experimental feasibility of empirical material decomposition for spectral CT using photon-counting detectors. PMID:25813054

  5. Detection of Primary Malignancy and Metastases with FDG PET/CT in Patients with Cholangiocarcinomas: Lesion-based Comparison with Contrast Enhanced CT

    PubMed Central

    Elias, Youssef; Mariano, Aladin T.; Lu, Yang

    2016-01-01

    The current National Comprehensive Cancer Network (NCCN) Guidelines consider the role of 2-deoxy-2-18F-fluoro-d-glucose positron emission tomography/computer tomography (FDG PET/CT) in the evaluation of cholangiocarcinoma (CCA) as "uncertain," and have recommended contrast enhanced computed tomography (CECT) but not FDG PET/CT as a routine imaging test for CCA workup. We set out to compare the diagnostic performance of FDG PET/CT and CECT in patients with CCA. The retrospective study included patients with CCA who underwent FDG PET/CT and CECT within 2-month interval between 2011 and 2013 in our hospital. Lesion-based comparison was conducted. Final diagnoses were made based on the composite clinical and imaging data with minimal 6-month follow-up. A total of 18 patients with 28-paired tests were included. There is a total of 142 true malignant lesions as revealed by the 6-paired pre-treatment and 22-paired post-treatment tests. On a lesion-based analysis, the sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and accuracies of PET/CT and CECT for detection of CCA were 96.5%, 55.5%, 97.2%, 50.0%, 94.1% and 62.2%, 66.7%, 96.7%, 10.0%, 62.5%, respectively. FDG PET/CT detected more intrahepatic malignant and extrahepatic metastases; and had significant higher sensitivity, NPV, and accuracy than CECT, while similar in specificity and PPV. No true positive lesion detected on CECT that was missed on PET/CT, and none of the false negative lesions on PET/CT were detected on CECT. Six patients had paired pretreatment tests, and FDG PET/CT results changed planned management in three patients. Our data suggest that FDG PET/CT detect more primary and metastatic lesions and lead to considerable changes in treatment plan in comparison with CECT. PMID:27651736

  6. Detection of Primary Malignancy and Metastases with FDG PET/CT in Patients with Cholangiocarcinomas: Lesion-based Comparison with Contrast Enhanced CT

    PubMed Central

    Elias, Youssef; Mariano, Aladin T.; Lu, Yang

    2016-01-01

    The current National Comprehensive Cancer Network (NCCN) Guidelines consider the role of 2-deoxy-2-18F-fluoro-d-glucose positron emission tomography/computer tomography (FDG PET/CT) in the evaluation of cholangiocarcinoma (CCA) as "uncertain," and have recommended contrast enhanced computed tomography (CECT) but not FDG PET/CT as a routine imaging test for CCA workup. We set out to compare the diagnostic performance of FDG PET/CT and CECT in patients with CCA. The retrospective study included patients with CCA who underwent FDG PET/CT and CECT within 2-month interval between 2011 and 2013 in our hospital. Lesion-based comparison was conducted. Final diagnoses were made based on the composite clinical and imaging data with minimal 6-month follow-up. A total of 18 patients with 28-paired tests were included. There is a total of 142 true malignant lesions as revealed by the 6-paired pre-treatment and 22-paired post-treatment tests. On a lesion-based analysis, the sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and accuracies of PET/CT and CECT for detection of CCA were 96.5%, 55.5%, 97.2%, 50.0%, 94.1% and 62.2%, 66.7%, 96.7%, 10.0%, 62.5%, respectively. FDG PET/CT detected more intrahepatic malignant and extrahepatic metastases; and had significant higher sensitivity, NPV, and accuracy than CECT, while similar in specificity and PPV. No true positive lesion detected on CECT that was missed on PET/CT, and none of the false negative lesions on PET/CT were detected on CECT. Six patients had paired pretreatment tests, and FDG PET/CT results changed planned management in three patients. Our data suggest that FDG PET/CT detect more primary and metastatic lesions and lead to considerable changes in treatment plan in comparison with CECT.

  7. Detection of Primary Malignancy and Metastases with FDG PET/CT in Patients with Cholangiocarcinomas: Lesion-based Comparison with Contrast Enhanced CT.

    PubMed

    Elias, Youssef; Mariano, Aladin T; Lu, Yang

    2016-09-01

    The current National Comprehensive Cancer Network (NCCN) Guidelines consider the role of 2-deoxy-2-(18)F-fluoro-d-glucose positron emission tomography/computer tomography (FDG PET/CT) in the evaluation of cholangiocarcinoma (CCA) as "uncertain," and have recommended contrast enhanced computed tomography (CECT) but not FDG PET/CT as a routine imaging test for CCA workup. We set out to compare the diagnostic performance of FDG PET/CT and CECT in patients with CCA. The retrospective study included patients with CCA who underwent FDG PET/CT and CECT within 2-month interval between 2011 and 2013 in our hospital. Lesion-based comparison was conducted. Final diagnoses were made based on the composite clinical and imaging data with minimal 6-month follow-up. A total of 18 patients with 28-paired tests were included. There is a total of 142 true malignant lesions as revealed by the 6-paired pre-treatment and 22-paired post-treatment tests. On a lesion-based analysis, the sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and accuracies of PET/CT and CECT for detection of CCA were 96.5%, 55.5%, 97.2%, 50.0%, 94.1% and 62.2%, 66.7%, 96.7%, 10.0%, 62.5%, respectively. FDG PET/CT detected more intrahepatic malignant and extrahepatic metastases; and had significant higher sensitivity, NPV, and accuracy than CECT, while similar in specificity and PPV. No true positive lesion detected on CECT that was missed on PET/CT, and none of the false negative lesions on PET/CT were detected on CECT. Six patients had paired pretreatment tests, and FDG PET/CT results changed planned management in three patients. Our data suggest that FDG PET/CT detect more primary and metastatic lesions and lead to considerable changes in treatment plan in comparison with CECT. PMID:27651736

  8. 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.

  9. 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.

  10. Comparison of CT-derived ventilation maps with deposition patterns of inhaled microspheres in rats

    PubMed Central

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

    2016-01-01

    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. PMID:25513951

  11. Comparison of SPECT/CT, MRI and CT in diagnosis of skull base bone invasion in nasopharyngeal carcinoma.

    PubMed

    Zhang, Shu-xu; Han, Peng-hui; Zhang, Guo-qian; Wang, Rui-hao; Ge, Yong-bin; Ren, Zhi-gang; Li, Jian-sheng; Fu, Wen-hai

    2014-01-01

    Early detection of skull base invasion in nasopharyngeal carcinoma (NPC) is crucial for correct staging, assessing treatment response and contouring the tumor target in radiotherapy planning, as well as improving the patient's prognosis. To compare the diagnostic efficacy of single photon emission computed tomography/computed tomography (SPECT/CT) imaging, magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of skull base invasion in NPC. Sixty untreated patients with histologically proven NPC underwent SPECT/CT imaging, contrast-enhanced MRI and CT. Of the 60 patients, 30 had skull base invasion confirmed by the final results of contrast-enhanced MRI, CT and six-month follow-up imaging (MRI and CT). The diagnostic efficacy of the three imaging modalities in detecting skull base invasion was evaluated. The rates of positive findings of skull base invasion for SPECT/CT, MRI and CT were 53.3%, 48.3% and 33.3%, respectively. The sensitivity, specificity and accuracy were 93.3%, 86.7% and 90.0% for SPECT/CT fusion imaging, 96.7%, 100.0% and 98.3% for contrast-enhanced MRI, and 66.7%, 100.0% and 83.3% for contrast-enhanced CT. MRI showed the best performance for the diagnosis of skull base invasion in nasopharyngeal carcinoma, followed closely by SPECT/CT. SPECT/CT had poorer specificity than that of both MRI and CT, while CT had the lowest sensitivity.

  12. Special computer-aided computed tomography (CT) volume measurement and comparison method for pulmonary tuberculosis (TB)

    PubMed Central

    Liu, Jingming; Sun, Zhaogang; Xie, Ruming; Gao, Mengqiu; Li, Chuanyou

    2015-01-01

    The computed tomography (CT) manifestations in pulmonary tuberculosis (PTB) patients are complex and could not be quantitatively evaluated. We aimed to establish a new method to objectively measure the lung injury level in PTB by thoracic CT and make quantitative comparisons. In the retrospective study, a total of 360 adults were selected and divided into four groups according to their CT manifestations and medical history: Normal group, PTB group, PTB with diabetes mellitus (DM) group and Death caused by PTB group. Five additional patients who had continuous CT scans were chosen for preliminary longitudinal analysis. We established a new computer-aided CT volume measurement and comparison method for PTB patients (CACTV-PTB) which measured lung volume (LV) and thoracic volume (TV). RLT was calculated as the ratio of LV to TV and comparisons were performed among different groups. Standardized RLT (SRLT) was used in the longitudinal analysis among different patients. In the Normal group, LV and TV were positively correlated in linear regression (Ŷ=-0.5+0.46X, R2=0.796, P<0.01). RLT values were significantly different among four groups (Normal: 0.40±0.05, PTB: 0.37±0.08, PTB+DM: 0.34±0.06, Death: 0.23±0.04). The curves of SRLT value from different patients shared a same start point and could be compared directly. Utilizing the novel objective method CACTV-PTB makes it possible to compare the severity and dynamic change among different PTB patients. Our early experience also suggested that the lung injury is severer in the PTB+DM group than in the PTB group. PMID:26628995

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Comparison of full-scan and half-scan for cone beam breast CT imaging

    NASA Astrophysics Data System (ADS)

    Chen, Lingyun; Shaw, Chris C.; Lai, Chao-jen; Altunbas, Mustafa C.; Wang, Tianpeng; Tu, Shu-ju; Liu, Xinming

    2006-03-01

    The half-scan cone beam technique, requiring a scan for 180° plus detector width only, can help achieve both shorter scan time as well as higher exposure in each individual projection image. This purpose of this paper is to investigate whether half-scan cone beam CT technique can provide acceptable images for clinical application. The half-scan cone beam reconstruction algorithm uses modified Parker's weighting function and reconstructs from slightly more than half of the projection views for full-scan, giving out promising results. A rotation phantom, stationary gantry bench top system was built to conduct experiments to evaluate half-scan cone beam breast CT technique. A post-mastectomy breast specimen, a stack of lunch meat slices embedded with various sizes of calcifications and a polycarbonate phantom inserted with glandular and adipose tissue equivalents are imaged and reconstructed for comparison study. A subset of full-scan projection images of a mastectomy specimen were extracted and used as the half-scan projection data for reconstruction. The results show half-scan reconstruction algorithm for cone beam breast CT images does not significantly degrade image quality when compared with the images of same or even half the radiation dose level. Our results are encouraging, emphasizing the potential advantages in the use of half-scan technique for cone beam breast imaging.

  2. Comparison of FDG-PET/CT and CT for Delineation of Lumpectomy Cavity for Partial Breast Irradiation

    SciTech Connect

    Ford, Eric C. Lavely, William C.; Frassica, Deborah A.; Myers, Lee T.; Asrari, Fariba; Wahl, Richard L.; Zellars, Richard C.

    2008-06-01

    Purpose: The success of partial breast irradiation critically depends on proper target localization. We examined the use of fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) for improved lumpectomy cavity (LC) delineation and treatment planning. Methods and Materials: Twelve breast cancer patients underwent FDG-PET/CT on a GE Discovery scanner with a median time from surgery to PET/CT of 49 days. The LC was contoured on the CT scan by a radiation oncologist and, together with a nuclear medicine physician, on the PET/CT scan. The volumes were calculated and compared in each patient. Treatment planning target volumes (PTVs) were calculated by expanding the margin 2 cm beyond the LC, maintaining a 5-mm margin from the skin and chest wall, and the treatment plans were evaluated. In addition, a study with a patient-like phantom was conducted to evaluate the effect that the window/level settings might have on contouring. Results: The margin of the LC was well visualized on all FDG-PET images. The phantom results indicated that the difference between the known volume and the FDG-PET-delineated volume was <10%, regardless of the window/level settings. The PET/CT volumes were larger than the CT volumes in all cases (median volume ratio, 1.68; range, 1.24-2.45; p = 0.004). The PET/CT-based PTVs were also larger than the CT-based PTV (median volume ratio, 1.16; range, 1.08-1.64; p = 0.006). In 9 of 12 patients, a CT-based treatment plan did not provide adequate coverage of the PET/CT-based PTV (99% of the PTV received <95% of the prescribed dose), resulting in substantial cold spots in some plans. In these cases, treatment plans were generated which were specifically designed to cover the larger PET/CT-based PTV. Although these plans showed an increased dose to the normal tissues, the increases were modest: the non-target breast volume receiving {>=}50 Gy, lung volume receiving {>=}30 Gy, and heart volume receiving {>=}5 Gy increased by 5

  3. 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.

  4. 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.

  5. Machine-learning based comparison of CT-perfusion maps and dual energy CT for pancreatic tumor detection

    NASA Astrophysics Data System (ADS)

    Goetz, Michael; Skornitzke, Stephan; Weber, Christian; Fritz, Franziska; Mayer, Philipp; Koell, Marco; Stiller, Wolfram; Maier-Hein, Klaus H.

    2016-03-01

    Perfusion CT is well-suited for diagnosis of pancreatic tumors but tends to be associated with a high radiation exposure. Dual-energy CT (DECT) might be an alternative to perfusion CT, offering correlating contrasts while being acquired at lower radiation doses. While previous studies compared intensities of Dual Energy iodine maps and CT-perfusion maps, no study has assessed the combined discriminative power of all information that can be generated from an acquisition of both functional imaging methods. We therefore propose the use of a machine learning algorithm for assessing the amount of information that becomes available by the combination of multiple images. For this, we train a classifier on both imaging methods, using a new approach that allows us to train only from small regions of interests (ROIs). This makes our study comparable to other - ROI-based analysis - and still allows comparing the ability of both classifiers to discriminate between healthy and tumorous tissue. We were able to train classifiers that yield DICE scores over 80% with both imaging methods. This indicates that Dual Energy Iodine maps might be used for diagnosis of pancreatic tumors instead of Perfusion CT, although the detection rate is lower. We also present tumor risk maps that visualize possible tumorous areas in an intuitive way and can be used during diagnosis as an additional information source.

  6. 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

  7. 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.

  8. 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.

  9. 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).

  10. 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

  11. 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

  12. 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

  13. Psychiatry on death row.

    PubMed

    Hussain, A H; Tozman, S

    1978-03-01

    The authors present the personal experiences of an attending physician in a Death Row in Ceylon (Sri-Lanka). Aspects of the execution scenario are presented and discussed with its implications for the protagonists: the condemned, witnesses, standers-by, authorities and society-at large.

  14. A direct comparison of the sensitivity of CT and MR cardiac perfusion using a myocardial perfusion phantom

    PubMed Central

    Otton, James; Morton, Geraint; Schuster, Andreas; Bigalke, Boris; Marano, Riccardo; Olivotti, Luca; Nagel, Eike; Chiribiri, Amedeo

    2013-01-01

    Background Direct comparison of CT and magnetic resonance (MR) perfusion techniques has been limited and in vivo assessment is affected by physiological variability, timing of image acquisition, and parameter selection. Objective We precisely compared high-resolution k-t SENSE MR cardiac perfusion at 3 T with single-phase CT perfusion (CTP) under identical imaging conditions. Methods We used a customized MR imaging and CT compatible dynamic myocardial perfusion phantom to represent the human circulation. CT perfusion studies were performed with a Philips iCT (256 slice) CT, with isotropic resolution of 0.6 mm3. MR perfusion was performed with k-t SENSE acceleration at 3 T and spatial resolution of 1.2 × 1.2 × 10 mm. The image contrast between normal and underperfused myocardial compartments was quantified at various perfusion and photon energy settings. Noise estimates were based on published clinical data. Results Contrast by CTP highly depends on photon energy and also timing of imaging within the myocardial perfusion upslope. For an identical myocardial perfusion deficit, the native image contrast-to-noise ratio (CNR) generated by CT and MR are similar. If slice averaging is used, the CNR of a perfusion deficit is expected to be greater for CTP than MR perfusion (MRP). Perfect timing during single time point CTP imaging is difficult to achieve, and CNR by CT decreases by 24%–31% two seconds from the optimal imaging time point. Although single-phase CT perfusion offers higher spatial resolution, MRP allows multiple time point sampling and quantitative analysis. Conclusion The ability of CTP and current optimal MRP techniques to detect simulated myocardial perfusion deficits is similar. PMID:23622506

  15. 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

  16. Comparison of CT and fiberoptic bronchoscopy in the evaluation of bronchial disease.

    PubMed

    Naidich, D P; Lee, J J; Garay, S M; McCauley, D I; Aranda, C P; Boyd, A D

    1987-01-01

    CT was compared to fiberoptic bronchoscopy in a large series of patients to study the value of CT for visualizing bronchial disease. CT scans were available for review in 64 cases in which focal airway disease was identified with fiberoptic bronchoscopy and in 38 patients in whom the airways appeared normal at bronchoscopy. CT was positive in 59 of 64 cases in which lesions were detected endoscopically. If the results are analyzed according to the extent of involvement of individual bronchi, CT successfully identified 88 (90%) of 98 lesions. CT correctly excluded disease in 35 (92%) of 38 cases that were subsequently verified to be normal by fiberoptic bronchoscopy. In no case was the diagnosis of malignancy missed by CT. While extremely accurate in detecting focal lesions, CT was inaccurate in predicting whether a given abnormality was endobronchial, submucosal, or extrinsic (peribronchial). In three cases CT failed to detect submucosal extension into the left mainstream bronchus, which has important implications concerning the value of CT in staging bronchial malignancy. It is concluded that CT is helpful when bronchoscopy is contraindicated or refused. CT may also be used in selected cases when there is low clinical suspicion of endobronchial disease and as a complementary procedure to fiberoptic bronchoscopy for outlining the exact location of major mediastinal and hilar vessels, lymph nodes, and tumor in relation to adjacent airways. PMID:3491497

  17. Quantification of Pathologic Air Trapping in Lung Transplant Patients Using CT Density Mapping: Comparison with Other CT Air Trapping Measures.

    PubMed

    Solyanik, Olga; Hollmann, Patrick; Dettmer, Sabine; Kaireit, Till; Schaefer-Prokop, Cornelia; Wacker, Frank; Vogel-Claussen, Jens; Shin, Hoen-oh

    2015-01-01

    To determine whether density mapping (DM) is more accurate for detection and quantification of pathologic air trapping (pAT) in patients after lung transplantation compared to other CT air trapping measures. One-hundred forty-seven lung and heart-lung transplant recipients underwent CT-examinations at functional residual capacity (FRC) and total lung capacity (TLC) and PFT six months after lung transplantation. Quantification of air trapping was performed with the threshold-based method in expiration (EXP), density mapping (DM) and the expiratory to inspiratory ratio of the mean lung density (E/I-ratio MLD). A non-rigid registration of inspiration-expiration CT-data with a following voxel-to-voxel mapping was carried out for DM. Systematic variation of attenuation ranges was performed for EXP and DM and correlated with the ratio of residual volume to total lung capacity (RV/TLC) by Spearman rank correlation test. AT was considered pathologic if RV/TLC was above the 95th percentile of the predicted upper limit of normal values. Receiver operating characteristic (ROC) analysis was performed. The optimal attenuation range for the EXP method was from -790 HU to -950 HU (EXP(-790 to -950HU)) (r = 0.524, p<0.001) to detect air trapping. Within the segmented lung parenchyma, AT was best defined as voxel difference less than 80 HU between expiration and registered inspiration using the DM method. DM correlated best with RV/TLC (r = 0.663, p<0.001). DM and E/I-ratio MLD showed a larger AUC (0.78; 95% CI 0.69-0.86; 0.76, 95% CI 0.67-0.85) than EXP(-790 HU to -950 HU) (0.71, 95% CI 0.63-0.78). DM and E/I-ratio MLD showed better correlation with RV/TLC and are more suited quantitative CT-methods to detect pAT in lung transplant patients than the EXP(-790HU to -950HU).

  18. 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

  19. Comparison of dosimetry between PET/CT and PET alone using (11)C-ITMM.

    PubMed

    Ito, Kimiteru; Sakata, Muneyuki; Oda, Keiichi; Wagatsuma, Kei; Toyohara, Jun; Ishibashi, Kenji; Ishii, Kenji; Ishiwata, Kiichi

    2016-03-01

    We used a new tracer, N-[4-[6-(isopropylamino) pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-(11)C-methoxy-N-methylbenzamide ((11)C-ITMM), to compare radiation doses from positron emission tomography (PET)/computed tomography (CT) with previously published doses from PET alone. Twelve healthy volunteers [six males (mean age ± SD, 27.7 ± 6.7 years) and six females (31.8 ± 14.5 years)] in 12 examinations were recruited. Dose estimations from PET/CT were compared with those from PET alone. Regions of interest (ROIs) in PET/CT were delineated on the basis of low-dose CT (LD-CT) images acquired during PET/CT. Internal and external radiation doses were estimated using OLINDA/EXM 1.0 and CT-Expo software. The effective dose (ED) for (11)C-ITMM calculated from PET/CT was estimated to be 4.7 ± 0.5 μSv/MBq for the male subjects and 4.1 ± 0.7 μSv/MBq for the female subjects. The mean ED for (11)C-ITMM calculated from PET alone in a previous report was estimated to be 4.6 ± 0.3 μSv/MBq (males, n = 3). The ED values for (11)C-ITMM calculated from PET/CT in the male subjects were almost identical to those from PET alone. The absorbed doses (ADs) of the gallbladder, stomach, red bone marrow, and spleen calculated from PET/CT were significantly different from those calculated from PET alone. The EDs of (11)C-ITMM calculated from PET/CT were almost identical to those calculated from PET alone. The ADs in several organs calculated from PET/CT differed from those from PET alone. LD-CT images acquired during PET/CT may facilitate organ identification.

  20. 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.

  1. Computer-aided CT coronary artery stenosis detection: comparison with human reading and quantitative coronary angiography.

    PubMed

    Rief, Matthias; Kranz, Anisha; Hartmann, Lisa; Roehle, Robert; Laule, Michael; Dewey, Marc

    2014-12-01

    To evaluate computer-aided stenosis detection for computed tomography coronary angiography (CTA) in comparison with human reading and conventional coronary angiography (CCA) as the reference standard. 50 patients underwent CTA and CCA and out of these 44 were evaluable for computer-aided stenosis detection. The diagnostic performance of the software and of human reading were compared and quantitative coronary angiography (QCA) served as the reference standard for the detection of significant stenosis (>50 %). Overall, three readers with high (reader 1), intermediate (reader 2) and low (reader 3) experience in cardiac CT imaging performed the manual CTA evaluation on a commercially available workstation, whereas the automated software processed the datasets without any human interaction. The prevalence of coronary artery disease was 41 % (18/44) and QCA indicated significant stenosis (>50 %) in 33 coronary vessels. The automated software accurately diagnosed 18 individuals with significant coronary artery disease (CAD), and correctly ruled out CAD in 10 patients. In summary the sensitivity of computer-aided detection was 100 %/94 % (per-patient/per-vessel) and the specificity was 38 %/70 %, the positive predictive value (PPV) was 53 %/42 % and the negative predictive value (NPV) was 100 %/98 %. In comparison, reader 1-3 showed per-patient sensitivities of 100/94/89 %, specificities of 73/69/50 %, PPVs of 72/68/55 % and NPVs of 100/95/87 %. Computer-aided detection yields a high NPV that is comparable to more experienced human readers. However, PPV is rather low and in the range of an unexperienced reader.

  2. Vertebral rotation measurement: a summary and comparison of common radiographic and CT methods

    PubMed Central

    Lam, Gabrielle C; Hill, Doug L; Le, Lawrence H; Raso, Jim V; Lou, Edmond H

    2008-01-01

    Current research has provided a more comprehensive understanding of Adolescent Idiopathic Scoliosis (AIS) as a three-dimensional spinal deformity, encompassing both lateral and rotational components. Apart from quantifying curve severity using the Cobb angle, vertebral rotation has become increasingly prominent in the study of scoliosis. It demonstrates significance in both preoperative and postoperative assessment, providing better appreciation of the impact of bracing or surgical interventions. In the past, the need for computer resources, digitizers and custom software limited studies of rotation to research performed after a patient left the scoliosis clinic. With advanced technology, however, rotation measurements are now more feasible. While numerous vertebral rotation measurement methods have been developed and tested, thorough comparisons of these are still relatively unexplored. This review discusses the advantages and disadvantages of six common measurement techniques based on technology most pertinent in clinical settings: radiography (Cobb, Nash-Moe, Perdriolle and Stokes' method) and computer tomography (CT) imaging (Aaro-Dahlborn and Ho's method). Better insight into the clinical suitability of rotation measurement methods currently available is presented, along with a discussion of critical concerns that should be addressed in future studies and development of new methods. PMID:18976498

  3. 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.

  4. Evaluation of bone substitute materials: comparison of flat-panel based volume CT to conventional multidetector CT.

    PubMed

    Sauerbier, Sebastian; Duttenhoefer, Fabian; Sachlos, Elefterios; Haberstroh, Jörg; Scheifele, Christian; Wrbas, Karl-Thomas; Voss, Pit Jacob; Veigel, Egle; Smedek, Jörg; Ganter, Philip; Tuna, Taskin; Gutwald, Ralf; Palmowski, Moritz

    2013-10-01

    Over the last decade tissue engineering has emerged as a key factor in bone regeneration within the field of cranio-maxillofacial surgery. Despite this in vivo analysis of tissue-engineered-constructs to monitor bone rehabilitation are difficult to conduct. Novel high-resolving flat-panel based volume CTs (fp-VCT) are increasingly used for imaging bone structures. This study compares the potential value of novel fp-VCT with conventional multidetector CT (MDCT) based on a sheep sinus floor elevation model. Calcium-hydroxyapatite reinforced collagen scaffolds were populated with autologous osteoblasts and implanted into sheep maxillary sinus. After 8, 16 and 24 weeks MDCT and fp-VCT scans were performed to investigate the volume of the augmented area; densities of cancellous and compact bone were assessed as comparative values. fp-VCT imaging resulted in higher spatial resolution, which was advantageous when separating closely related anatomical structures (i.e. trabecular and compact bone, biomaterials). Fp-VCT facilitated imaging of alterations occurring in test specimens over time. fp-VCTs therefore displayed high volume coverage, dynamic imaging potential and superior performance when investigating superfine bone structures and bone remodelling of biomaterials. Thus, fp-VCTs may be a suitable instrument for intraoperative imaging and future in vivo tissue-engineering studies.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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 ...

  12. 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

  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. Efficacy of Multidetector-Row Computed Tomography as a Practical Tool in Comparison to Invasive Procedures for Visualization of the Biliary Obstruction

    PubMed Central

    Taheri, Abdolmajid; Rostamzadeh, Ayoob; Gharib, Alireza; Fatehi, Daryoush

    2016-01-01

    Introduction: Recently, multidetector computed tomography (MDCT) has been introduced into clinical practice. MDCT has become the noninvasive diagnostic test of choice for detailed evaluation of biliary obstruction. Aim: the main objective of the present study was to evaluate the diagnostic value of MDCT compared to invasive procedures for detecting biliary obstruction causes. Material and Methods: Since February 2009 until May 2011 fifty biliary obstruction patients based on clinical, laboratory or ultrasonographic findings, were evaluated by Multidetector-row computed tomography. The causes of biliary obstruction, which was identified using. MDCT were classified into three categories: calculus, benign stricture, and malignancy. Final diagnosis was conducted based on percutaneous transhepatic cholangiography (PTC), endoscopic retrograde cholangiopancreatography, biopsy, or surgery. The MDCT diagnosis and were compared with the final diagnosis. Results: A correct diagnosis of causes of biliaryobstruction was made on the basis of MDCT findings for 44 of the total 50 patients. Two patients with chronic pancreatitis were incorrectly diagnosed with a pancreatic head adenocarcinoma on the basis of MDCT findings. One patient with biliary stone was incorrectly diagnosed with a periampullary adenocarcinoma on the basis of MDCT findings. The Sensitivity, specificity and accuracy of MDCT in the diagnosis of causes of biliary obstruction were 94.12% and87.87% and94.6% respectively. Conclusion: Based on the findings of this study MDCT has an excellent image quality, providing valuable information about the biliary tree and other abdominal organs. The use of advanced image processing, including maximum intensity projection and multiplanar reconstruction (especially coronal or sagittal reformatted images), allows superior visualization of the biliary tree and vascular structures. Three-dimensional reconstruction images complement axial images by providing a more anatomically

  15. 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)

  16. A clinical comparison of CT1341, ketamine, and xylazine in cats.

    PubMed

    Haskins, S C; Peiffer, R L; Stowe, C M

    1975-10-01

    The new anesthetic agent CT1341 was compared to ketamine and xylazine in experimental and clinical situations with cats. Anesthesia with CT1341 was characterized by fast recovery times, good muscle relaxation, eyelid closure, occasional vomition, defecation, or urination during induction and recovery, generally smooth induction, and occasional hyperreflexive recoveries with much sneezing. The agent was moderately hypotensive, but caused little change in heart rate, central venous pressure, arterial pH, or blood gases. PMID:1190595

  17. [CT and MR virtual colonscopy: indications, limits and comparison with conventional colonscopy].

    PubMed

    Bertini, L; Campagnano, S; Lanciotti, S; Fiorello, S; Fabiani, B; Graziani, M G; Gualdi, G F

    2006-01-01

    Virtual endoscopy is a new method for studying the colon; it consists in acquisition of CT and MR images and to elaborate them with a workstation, to create endoluminal vision as like as traditional colonscopy, permitting the complete exploration of colonic lumen, also with stenotic tumors. The analysis of the differences between CT and MR colography shows like these two techniques present both advantages and disadvantages, such as the impossibility to perform MR in patients with pace-maker or in claustrophobic patients and the impossibility to perform CT with iodated agents in patients with renal failure or with a story of adverse reactions. The increased use of these techniques is due to the high sensitivity of last-generation CT and MR machine, to the increased spatial resolution, to specific softwares for digital cleaning of colon, to the introduction of high-end workstations and to the possibility of computed assisted diagnosis (CAD). So, it is desiderable that the increasing spread of multidetector CT devices and the future technical innovations, should have the effect to increase culture and experience in various diagnostic centers about CT-colography, making possible the spreading of virtual endoscopy as a screening tool.

  18. Comparison of spiral CT and US in the evaluation of pediatric urolithiasis.

    PubMed

    Oner, S; Oto, A; Tekgul, S; Koroglu, M; Hascicek, M; Sahin, A; Akhan, O

    2004-01-01

    The objective of the study was to determine the value of spiral computerized tomography (CT) in detecting urolithiasis in pediatric patients and compare its efficacy with ultrasound (US). Twenty-nine infants aged between 2 to 94 months with clinical presentation suggestive of urolithiasis and a negative or indeterminate plain film were included in the study. Abdominal US and spiral CT were performed in all patients. Presence, size and localization of stones were noted for each patient on both CT and US. The diagnosis of urolithiasis was confirmed by passage of stones spontaneously, extracorporeal shockwave lithotripsy (ESWL), surgery, or clinical follow-up. Presence of stones was confirmed in 23 of 29 patients (79%). Eight patients had single stone and the remaining 15 had multiple stones either in a single localization (single kidney or single ureter) or multiple localizations. Spiral CT detected 57 stones (45 renal and 12 ureteral). US detected 34 stones (59.6%) in 18 (78.2%) patients. US was able to localize 31 stones (68.8%) in 21 kidneys (75%), and 3 stones (25%) in 11 ureters (27.2%). Spiral CT is very effective in the diagnosis of pediatric urolithiasis. Spiral CT is more efficient than US in imaging pediatric patients with symptoms and signs of urolithiasis, when KUB is inconclusive.

  19. 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

  20. 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

  1. 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

  2. Magnetic resonance imaging of mediastinal and hilar masses: comparison with CT

    SciTech Connect

    Levitt, R.G.; Glazer, H.S.; Roper, C.L.; Lee, J.K.T.; Murphy, W.A.

    1985-07-01

    Magnetic resonance imaging (MRI) was compared to computed tomography (CT) of the mediastinum and/or hila in 37 patients with bronchogenic carcinoma (35 unresectable for cure) and 11 patients with other masses. Spin-echo pulse sequences using a short pulse repetition rate (TR) and short echo delay (TE) were most helpful for detection of abnormal soft-tissue mediastinal and hilar masses. The accuracy of MRI and CT in staging bronchogenic carcinoma for curative resectability/nonresectability was comparable. Several pitfalls in MRI evaluation of the mediastinum were identified. By MRI the esophagus may be misinterpreted as an enlarged retrotracheal lymph node unless serial scans are studied. Small adjacent lymph nodes shown individually by CT may appear as a single enlarged lymph node by MRI due to partial-volume averaging. Because of the requirement for patient selection and the identified pitfalls of MRI, CT remains the radiologic procedure of choice in the staging of patients with bronchogenic carcinoma and the evaluation of other mediastinal and hilar masses at present. However, because of the ability to show blood vessels without an intravascular contrast agent, MRI is useful in evaluating patients with potential contrast allergy and solving diagnostic problems not solved by CT.

  3. 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.

  4. 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

  5. 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

  6. Fluid collections in the intraperitoneal and extraperitoneal spaces: comparison of MR and CT

    SciTech Connect

    Cohen, J.M.; Weinreb, J.C.; Maravilla, K.R.

    1985-06-01

    Fourteen patients with abnormal subdiaphragmatic fluid collections were examined with computed tomography (CT) and magnetic resonance (MR) imaging. MR and CT provided equivalent information concerning the presence and extent of fluid collections in 13 of the 14 cases. Image acquisitions with two different repetition times (TRs) and two echo times (TEs) were necessary, in most cases, to detect and discriminate between different types of pathologic fluids. Transudative ascites demonstrated long T1 and T2 relaxation times, whereas abscesses, phlegmon, pancreatic pseudocyst, exudative pancreatitis, and chronic hematoma demonstrated an intermediate or short T1 and a long T2.

  7. Fluid collections in the intraperitoneal and extraperitoneal spaces: comparison of MR and CT.

    PubMed

    Cohen, J M; Weinreb, J C; Maravilla, K R

    1985-06-01

    Fourteen patients with abnormal subdiaphragmatic fluid collections (eight intraperitoneal, two extraperitoneal, and four intra- and extraperitoneal) were examined with computed tomography (CT) and magnetic resonance (MR) imaging. MR and CT provided equivalent information concerning the presence and extent of fluid collections in 13 of the 14 cases. Image acquisitions with two different repetition times (TRs) and two echo times (TEs) were necessary, in most cases, to detect and discriminate between different types of pathologic fluids. Transudative ascites demonstrated long T1 and T2 relaxation times, whereas abscesses, phlegmon, pancreatic pseudocyst, exudative pancreatitis, and chronic hematoma demonstrated an intermediate or short T1 and a long T2.

  8. Cerebral blood flow in volunteers measured by PET and Xe CT/CBF. A comparison.

    PubMed

    Bergholt, B; Ostergaard, L; von Oettingen, G; Johannsen, P; Poulsen, P H; Bundgaard, H; Asboe, H; Cold, G E; Gjedde, A; Gyldensted, C; Astrup, J

    2000-02-01

    Aim of this study was to compare two quantitative CBF methods. Seven young, healthy volunteers were studied with PET (15-0 labelled water) and afterwards with Xe CT/CBF (30% xenon in oxygen, 3 minutes wash-in, 5 minutes washout protocol). Xe CT/CBF showed greater differences between high and low flow areas than PET CBF. Correlation was found within subjects between ROI's, but no agreement or correlation between the methods could be demonstrated. The disagreement in this study could be due to changes in PCO2.

  9. Comparison of several artificial neural network classifiers for CT images of hardwood logs

    NASA Astrophysics Data System (ADS)

    Schmoldt, Daniel L.; He, Jing; Abbott, A. Lynn

    1998-02-01

    Knowledge of internal log defects, obtained by scanning, is critical to efficiency improvements for future hardwood sawmills. Nevertheless, before computed tomography (CT) scanning can be applied in industrial operations, we need to automatically interpret scan information so that it can provide the saw operator with the information necessary to make proper sawing decisions. Our current approach to automatically label features in CT images of hardwood logs classifies each pixel individually using a back-propagation artificial neural network (ANN) and feature vectors that include a small, local neighborhood of pixels and the distance of the target pixel to the center of the log. Initially, this ANN was able to classify clearwood, bark, decay, knots, and voids in CT images of two species of oak with 95% pixel-wise accuracy. Recently we have investigated other ANN classifiers, comparing 2D versus 3D neighborhoods and species-dependent (single species) versus species- independent (multiple species) classifiers using oak, yellow poplar, and cherry CT images. When considered individually, the resulting species-dependent classifiers yield similar levels of accuracy (96 - 98%). 3D neighborhoods work better for multiple-species classifiers and 2D is better for single-species. Under certain conditions there is no statistical difference in accuracy between single- and multiple-species classifiers, suggesting that a multiple- species classifier can be applied broadly with high accuracy.

  10. 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.

  11. CT pulmonary densitovolumetry in patients with acromegaly: a comparison between active disease and controlled disease

    PubMed Central

    Camilo, Gustavo B; Carvalho, Alysson R S; Machado, Dequitier C; Mogami, Roberto; Melo, Pedro L

    2015-01-01

    Objective: Our purpose was to compare the findings of CT pulmonary densitovolumetry and pulmonary function in patients with active acromegaly and controlled acromegaly and, secondarily, to correlate these findings. Methods: 11 patients with active acromegaly, 18 patients with controlled acromegaly and 17 control subjects, all non-smokers, underwent quantification of lung volume using multidetector CT (Q-MDCT) and pulmonary function tests. Results: Patients with active acromegaly had larger total lung mass (TLM) values than the controls and larger amounts of non-aerated compartments than the other two groups. Patients with active acromegaly also had larger amounts of poorly aerated compartments than the other two groups, a difference that was observed in both total lung volume (TLV) and TLM. TLV as measured by inspiratory Q-MDCT correlated significantly with total lung capacity, whereas TLV measured using expiratory Q-MDCT correlated significantly with functional residual capacity. Conclusion: Patients with active acromegaly have more lung mass and larger amounts of non-aerated and poorly aerated compartments. There is a relationship between the findings of CT pulmonary densitovolumetry and pulmonary function test parameters. Advances in knowledge: Although the nature of our results demands further investigation, our data suggest that both CT pulmonary densitovolumetry and pulmonary function tests can be used as useful tools for patients with acromegaly by assisting in the prediction of disease activity. PMID:26246281

  12. 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

  13. 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

  14. Comparison of SNOMED CT versus Medcin Terminology Concept Coverage for Mild Traumatic Brain Injury

    PubMed Central

    Montella, Diane; Brown, Steven H.; Elkin, Peter L.; Jackson, James C.; Rosenbloom, S. Trent; Wahner-Roedler, Dietlind; Welsh, Gail; Cotton, Bryan; Guillamondegui, Oscar D.; Lew, Henry; Taber, Katherine H.; Tupler, Larry A.; Vanderploeg, Rodney; Speroff, Theodore

    2011-01-01

    Background: Traumatic Brain Injury (TBI) is a “signature” injury of the current wars in Iraq and Afghanistan. Structured electronic data regarding TBI findings is important for research, population health and other secondary uses but requires appropriate underlying standard terminologies to ensure interoperability and reuse. Currently the U.S. Department of Veterans Affairs (VA) uses the terminology SNOMED CT and the Department of Defense (DOD) uses Medcin. Methods: We developed a comprehensive case definition of mild TBI composed of 68 clinical terms. Using automated and manual techniques, we evaluated how well the mild TBI case definition terms could be represented by SNOMED CT and Medcin, and compared the results. We performed additional analysis stratified by whether the concepts were rated by a TBI expert panel as having High, Medium, or Low importance to the definition of mild TBI. Results: SNOMED CT sensitivity (recall) was 90% overall for coverage of mild TBI concepts, and Medcin sensitivity was 49%, p < 0.001 (using McNemar’s chi square). Positive predictive value (precision) for each was 100%. SNOMED CT outperformed Medcin for concept coverage independent of import rating by our TBI experts. Discussion: SNOMED CT was significantly better able to represent mild TBI concepts than Medcin. This finding may inform data gathering, management and sharing, and data exchange strategies between the VA and DOD for active duty soldiers and veterans with mild TBI. Since mild TBI is an important condition in the civilian population as well, the current study results may be useful also for the general medical setting. PMID:22195156

  15. 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-...

  16. 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

  17. 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.

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

    PubMed

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

    2006-03-01

    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 2048x3072x12 bit CCD optically coupled to an image amplifier and an x-ray phosphor screen. The CCD has an intrinsic pixel size of 12 mum 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

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Comparison of methods for assessing geometric efficiency on multi-detector CT scanners.

    PubMed

    Berris, Theocharis; Perisinakis, Kostas; Papadakis, Antonios E; Damilakis, John

    2013-05-01

    The aim of the current study was to compare the film method against the method based on a new CT slice detector in assessing geometric efficiency (GE) of x-ray beams utilized by a multi-detector CT (MDCT) scanner. Measurements of GE were performed using radiographic films and a solid state CT slice detector for all beam qualities, collimations and focal spot sizes available on an MDCT scanner. Repeatability of GE measurements was assessed. The radiographic film and the solid state detector methods were compared to each other in regard to efficacy in measuring free-in-air GE. The values of GE determined using the radiographic film method were found to range between 48.5% and 90.6%. Differences between values obtained with the radiographic film method and corresponding values obtained with the solid state detector were less than 10% exceeding 5% for only one case. Both methods show that wide beams have higher GE values compared to thin ones. The use of large instead of small focal spot was found to deteriorate GE values by up to 23.1%. Beam quality did not seem to influence GE of the various collimations. When thin beam collimations are employed, a considerable amount of the radiation is wasted for non-imaging purposes. Both film and solid state probe methods are capable of measuring GE of thin as well as wide collimations. The solid state detector is the easiest to use, however its usefulness is reduced by the fact that it cannot measure dose profiles of beam collimations available for step-and-shoot mode of operation.

  4. 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.

  5. 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

  6. 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.

  7. Comparison of information-preserving and information-losing data-compression algorithms for CT images.

    PubMed

    Bramble, J M

    1989-02-01

    Data compression increases the number of images that can be stored on magnetic disks or tape and reduces the time required for transmission of images between stations. Two algorithms for data compression are compared in application to computed tomographic (CT) images. The first, an information-preserving algorithm combining differential and Huffman encoding, allows reconstruction of the original image. A second algorithm alters the image in a clinically acceptable manner. This second algorithm combines two processes: the suppression of data outside of the head or body and the combination of differential and Huffman encoding. Because the final image is not an exact copy, the second algorithm is information losing. Application of the information-preserving algorithm can double or triple the number of CT images that can be stored on hard disk or magnetic tape. This algorithm may also double or triple the speed with which images may be transmitted. The information-losing algorithm can increase storage or transmission speed by a factor of five. The computation time on this system is excessive, but dedicated hardware is available to allow efficient implementation.

  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 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

  10. 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

  11. 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

  12. 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…

  13. 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.

  14. Diagnostic Performance of Dual-Energy CT Stress Myocardial Perfusion Imaging: Direct Comparison With Cardiovascular MRI

    PubMed Central

    Ko, Sung Min; Song, Meong Gun; Chee, Hyun Kun; Hwang, Hweung Kon; Feuchtner, Gudrun Maria; Min, James K.

    2014-01-01

    OBJECTIVE The purpose of this study was to assess the diagnostic performance of stress perfusion dual-energy CT (DECT) and its incremental value when used with coronary CT angiography (CTA) for identifying hemodynamically significant coronary artery disease. SUBJECTS AND METHODS One hundred patients with suspected or known coronary artery disease without chronic myocardial infarction detected with coronary CTA underwent stress perfusion DECT, stress cardiovascular perfusion MRI, and invasive coronary angiography (ICA). Stress perfusion DECT and cardiovascular stress perfusion MR images were used for detecting perfusion defects. Coronary CTA and ICA were evaluated in the detection of ≥ 50% coronary stenosis. The diagnostic performance of coronary CTA for detecting hemodynamically significant stenosis was assessed before and after stress perfusion DECT on a pervessel basis with ICA and cardiovascular stress perfusion MRI as the reference standard. RESULTS The performance of stress perfusion DECT compared with cardiovascular stress perfusion MRI on a per-vessel basis in the detection of perfusion defects was sensitivity, 89%; specificity, 74%; positive predictive value, 73%; negative predictive value, 90%. Per segment, these values were sensitivity, 76%; specificity, 80%; positive predictive value, 63%; and negative predictive value, 88%. Compared with ICA and cardiovascular stress perfusion MRI per vessel territory the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA were 95%, 61%, 61%, and 95%. The values for stress perfusion DECT were 92%, 72%, 68%, and 94%. The values for coronary CTA and stress perfusion DECT were 88%, 79%, 73%, and 91%. The ROC AUC increased from 0.78 to 0.84 (p = 0.02) with the use of coronary CTA and stress perfusion DECT compared with coronary CTA alone. CONCLUSION Stress perfusion DECT plays a complementary role in enhancing the accuracy of coronary CTA for identifying hemodynamically

  15. Comparison of manual vs. automated multimodality (CT-MRI) image registration for brain tumors

    SciTech Connect

    Sarkar, Abhirup; Santiago, Roberto J.; Smith, Ryan; Kassaee, Alireza . E-mail: Kassaee@xrt.upenn.edu

    2005-03-31

    Computed tomgoraphy-magnetic resonance imaging (CT-MRI) registrations are routinely used for target-volume delineation of brain tumors. We clinically use 2 software packages based on manual operation and 1 automated package with 2 different algorithms: chamfer matching using bony structures, and mutual information using intensity patterns. In all registration algorithms, a minimum of 3 pairs of identical anatomical and preferably noncoplanar landmarks is used on each of the 2 image sets. In manual registration, the program registers these points and links the image sets using a 3-dimensional (3D) transformation. In automated registration, the 3 landmarks are used as an initial starting point and further processing is done to complete the registration. Using our registration packages, registration of CT and MRI was performed on 10 patients. We scored the results of each registration set based on the amount of time spent, the accuracy reported by the software, and a final evaluation. We evaluated each software program by measuring the residual error between 'matched' points on the right and left globes and the posterior fossa for fused image slices. In general, manual registration showed higher misalignment between corresponding points compared to automated registration using intensity matching. This error had no directional dependence and was, most of the time, larger for a larger structure in both registration techniques. Automated algorithm based on intensity matching also gave the best results in terms of registration accuracy, irrespective of whether or not the initial landmarks were chosen carefully, when compared to that done using bone matching algorithm. Intensity-matching algorithm required the least amount of user-time and provided better accuracy.

  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. 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

  18. 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

  19. 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

  20. 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....

  1. 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.

  2. 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.

  3. 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.

  4. Comparison of the Reliability of Anatomic Landmarks based on PA Cephalometric Radiographs and 3D CT Scans in Patients with Facial Asymmetry

    PubMed Central

    Rathee, Pooja; Jain, Pradeep; Panwar, Vasim Raja

    2011-01-01

    Introduction Conventional cephalometry is an inexpensive and well-established method for evaluating patients with dentofacial deformities. However, patients with major deformities and in particular asymmetric cases are difficult to evaluate by conventional cephalometry. Reliable and accurate evaluation in the orbital and midfacial region in craniofacial syndrome patients is difficult due to inherent geometric magnification, distortion and the superpositioning of the craniofacial structures on cephalograms. Both two- and three-dimensional computed tomography (CT) have been proposed to alleviate some of these difficulties. Aims and objectives The aim of our study is to compare the reliability of anatomic cephalometric points obtained from the two modalities: Conventional posteroanterior cephalograms and 3D CT of patients with facial asymmetry, by comparison of intra- and interobserver variation of points recorded from frontal X-ray to those recorded from 3D CT. Materials and methods The sample included nine patients (5 males and 4 females) with an age range of 14 to 21 years and a mean age of 17.11 years, whose treatment plan called for correction of facial asymmetry. All CT scans were measured twice by two investigators with 2 weeks separation for determination of intraobserver and interobserver variability. Similarly, all measurement points on the frontal cephalograms were traced twice with 2 weeks separation. The tracings were superimposed and the average distance between replicate points readings were used as a measure of intra- and interobserver reliability. Intra-and interobserver variations are calculated for each method and the data were imported directly into the statistical program, SPSS 10.0.1 for windows. Results Intraobserver variations of points defined on 3D CT were small compared with frontal cephalograms. The intraobserver variations ranged from 0 (A1, B1) to 0.6 mm with the variations less than 0.5 mm for most of the points. Interobserver variations

  5. Chlamydomonas flagellar outer row dynein assembly protein ODA7 interacts with both outer row and I1 inner row dyneins.

    PubMed

    Freshour, Judy; Yokoyama, Ruth; Mitchell, David R

    2007-02-23

    We previously found that a mutation at the ODA7 locus in Chlamydomonas prevents axonemal outer row dynein assembly by blocking association of heavy chains and intermediate chains in the cytoplasm. We have now cloned the ODA7 locus by walking in the Chlamydomonas genome from nearby molecular markers, confirmed the identity of the gene by rescuing the mutant phenotype with genomic clones, and identified the ODA7 gene product as a 58-kDa leucine-rich repeat protein unrelated to outer row dynein LC1. Oda7p is missing from oda7 mutant flagella but is present in flagella of other outer row or inner row dynein assembly mutants. However, Oda7 levels are greatly reduced in flagella that lack both outer row dynein and inner row I1 dynein. Biochemical fractionation and rebinding studies support a model in which Oda7 participates in a previously uncharacterized structural link between inner and outer row dyneins.

  6. 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%.

  7. 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

  8. 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

  9. 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.

  10. Estimation of lung motion fields in 4D CT data by variational non-linear intensity-based registration: A comparison and evaluation study.

    PubMed

    Werner, René; Schmidt-Richberg, Alexander; Handels, Heinz; Ehrhardt, Jan

    2014-08-01

    Accurate and robust estimation of motion fields in respiration-correlated CT (4D CT) images, usually performed by non-linear registration of the temporal CT frames, is a precondition for the analysis of patient-specific breathing dynamics and subsequent image-supported diagnostics and treatment planning. In this work, we present a comprehensive comparison and evaluation study of non-linear registration variants applied to the task of lung motion estimation in thoracic 4D CT data. In contrast to existing multi-institutional comparison studies (e.g. MIDRAS and EMPIRE10), we focus on the specific but common class of variational intensity-based non-parametric registration and analyze the impact of the different main building blocks of the underlying optimization problem: the distance measure to be minimized, the regularization approach and the transformation space considered during optimization. In total, 90 different combinations of building block instances are compared. Evaluated on proprietary and publicly accessible 4D CT images, landmark-based registration errors (TRE) between 1.14 and 1.20 mm for the most accurate registration variants demonstrate competitive performance of the applied general registration framework compared to other state-of-the-art approaches for lung CT registration. Although some specific trends can be observed, effects of interchanging individual instances of the building blocks on the TRE are in general rather small (no single outstanding registration variant existing); the same level of accuracy is, however, associated with significantly different degrees of motion field smoothness and computational demands. Consequently, the building block combination of choice will depend on application-specific requirements on motion field characteristics.

  11. 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.

  12. 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.

  13. Noise-resolution tradeoffs in x-ray CT imaging: A comparison of penalized alternating minimization and filtered backprojection algorithms

    SciTech Connect

    Evans, Joshua D.; Politte, David G.; Whiting, Bruce R.; O'Sullivan, Joseph A.; Williamson, Jeffrey F.

    2011-03-15

    Purpose: In comparison with conventional filtered backprojection (FBP) algorithms for x-ray computed tomography (CT) image reconstruction, statistical algorithms directly incorporate the random nature of the data and do not assume CT data are linear, noiseless functions of the attenuation line integral. Thus, it has been hypothesized that statistical image reconstruction may support a more favorable tradeoff than FBP between image noise and spatial resolution in dose-limited applications. The purpose of this study is to evaluate the noise-resolution tradeoff for the alternating minimization (AM) algorithm regularized using a nonquadratic penalty function. Methods: Idealized monoenergetic CT projection data with Poisson noise were simulated for two phantoms with inserts of varying contrast (7%-238%) and distance from the field-of-view (FOV) center (2-6.5 cm). Images were reconstructed for the simulated projection data by the FBP algorithm and two penalty function parameter values of the penalized AM algorithm. Each algorithm was run with a range of smoothing strengths to allow quantification of the noise-resolution tradeoff curve. Image noise is quantified as the standard deviation in the water background around each contrast insert. Modulation transfer functions (MTFs) were calculated from six-parameter model fits to oversampled edge-spread functions defined by the circular contrast-insert edges as a metric of local resolution. The integral of the MTF up to 0.5 lp/mm was adopted as a single-parameter measure of local spatial resolution. Results: The penalized AM algorithm noise-resolution tradeoff curve was always more favorable than that of the FBP algorithm. While resolution and noise are found to vary as a function of distance from the FOV center differently for the two algorithms, the ratio of noises when matching the resolution metric is relatively uniform over the image. The ratio of AM-to-FBP image variances, a predictor of dose-reduction potential, was

  14. 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.

  15. Characterization of focal liver lesions with SonoVue®-enhanced sonography: International multicenter-study in comparison to CT and MRI

    PubMed Central

    Trillaud, Hervé; Bruel, Jean-Michel; Valette, Pierre-Jean; Vilgrain, Valérie; Schmutz, Gérard; Oyen, Raymond; Jakubowski, Wieslaw; Danes, Jan; Valek, Vlastimil; Greis, Christian

    2009-01-01

    AIM: To evaluate in a multicenter study whether the sonographic characterization of focal liver lesions can be improved using SonoVue®-enhancement; and to compare this method with computed tomography (CT) and magnetic resonance imaging (MRI). METHODS: One hundred and thirty four patients with one focal liver lesion detected in baseline ultrasound (US) were examined with conventional US, contrast-enhanced US (n = 134), contrast-enhanced CT (n = 115) and/or dynamic contrast-enhanced MRI (n = 70). The lesions were classified as malignant, benign or indeterminate and the type of lesion was determined. The final diagnosis based on the combined information of all imaging examinations, clinical information and histology (n = 32) was used. Comparisons were made to see whether the addition of contrast-enhanced US led to the improvement of the characterization of doubtful focal liver lesions. RESULTS: In comparison with unenhanced US, SonoVue® markedly improves sensitivity and specificity for the characterization (malignant/benign) of focal liver lesions. In comparison with CT and/or dynamic MRI, SonoVue®-enhanced sonography applied for characterization of focal liver lesions was 30.2% more sensitive in the recognition of malignancy and 16.1% more specific in the exclusion of malignancy and overall 22.9% more accurate. In the subgroup with confirmative histology available (n = 30), sensitivity was 95.5% (CEUS), 72.2% (CT) and 81.8% (MRI), and specificity was 75.0% (CEUS), 37.5% (CT) and 42.9% (MRI). The sensitivity and specificity of CEUS for the identification of focal nodular hyperplasia (FNH) and hemangiomas was 100% and 87%, resulting in an accuracy of 94.5%. CONCLUSION: SonoVue®-enhanced sonography emerges as the most sensitive, most specific and thus most accurate imaging modality for the characterization of focal liver lesions. PMID:19673015

  16. 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

  17. Multidetector-row computed tomography in cerebral hydatid cyst

    PubMed Central

    Wani, Nisar A; Kosar, Tasleem L; Khan, Abdul Qayum; Ahmad, Sheikh Shahnawaz

    2010-01-01

    Intracranial localization is a rare manifestation of hydatid cyst disease (Echinococcosis). It comprises only 2% of cases of Echinococcosis infection even in endemic areas and is predominantly seen in children. Clinical manifestations resulting from raised intracranial tension are nonspecific. Imaging with computed tomography (CT) may suggest the diagnosis preoperatively with reasonable accuracy. Multidetector-row CT (MDCT) with its high resolution multiplanar reformations can demonstrate the relationship of the cyst with adjacent brain structures and thus help in planning surgery. This has a practical utility in places where magnetic resonance imaging is not available. We describe a case of cerebral hydatid cyst in a 13-year-old boy who was diagnosed with MDCT, which helped in planning its surgical removal. PMID:21808517

  18. 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.

  19. Clinical application of 320-row multidetector computed tomography for a dynamic three-dimensional vascular study: imaging findings and initial experience.

    PubMed

    Nagamatsu, Shogo; Nakagawa, Masahiro; Kayano, Shuji; Koizumi, Takuya; Akazawa, Satoshi; Onitsuka, Tetsuro; Iida, Yoshiyuki; Endo, Masahiro; Nakaya, Yoshihiro; Urikura, Atsushi

    2010-10-01

    The 320-row multidetector computed tomography (MDCT) is now used by both cardiologists and neurosurgeons. It enables dynamic 3D-CT angiography, because the wide-area detector eliminates helical scanning, thus achieving very fast scanning times for single 3D-CT volume data. Some microvascular surgeons are familiar with 64-row MDCT for perforator studies, but there are few reports of studies using 320-row MDCT. This MDCT system was used to follow the dynamic blood flow of small vessels. It is considered to have a great potential in the clinical field of microvascular surgery. PMID:20399163

  20. 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.

  1. 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)

  2. 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

  3. Setting up a Death Row Psychiatry Program.

    PubMed

    Yanofski, Jason

    2011-02-01

    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.

  4. Setting up a Death Row Psychiatry Program.

    PubMed

    Yanofski, Jason

    2011-02-01

    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

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Comparison of rankings for lean meat based on results from a CT scanner and a video image analysis system.

    PubMed

    Jay, N P; van de Ven, R J; Hopkins, D L

    2014-10-01

    Coopworth cross lambs born over three years were examined in this study. Differences between two machines; a computer tomography (CT) scanner and a VIAScan® system for the estimation of carcase lean weight in lamb carcases was examined. The CT scanner provided a significantly higher estimate of carcase lean. The rank correlation (0.84) between the CT scanner and the VIAScan® system for the prediction of carcase lean was significant, but there was a different ranking for carcase lean depending on which machine was used. This has important ramifications for the use of VIAScan® data in the New Zealand Sheep Improvement Ltd genetic programme.

  10. Reference standard and statistical model for intersite and temporal comparisons of CT attenuation in a multicenter quantitative lung study

    PubMed Central

    Sieren, J. P.; Newell, J. D.; Judy, P. F.; Lynch, D. A.; Chan, K. S.; Guo, J.; Hoffman, E. A.

    2012-01-01

    Purpose: The purpose of this study was to detect and analyze anomalies between a large number of computed tomography (CT) scanners, tracked over time, utilized to collect human pulmonary CT data for a national multicenter study: chronic obstructive pulmonary disease genetic epidemiology study (COPDGene). Methods: A custom designed CT reference standard “Test Object” has been developed to evaluate the relevant differences in CT attenuation between CT scanners in COPDGene. The materials used in the Test Object to assess CT scanner accuracy and precision included lung equivalent foam (−856 HU), internal air (−1000 HU), water (0 HU), and acrylic (120 HU). Nineteen examples of the Test Object were manufactured. Initially, all Test Objects were scanned on the same CT scanner before the Test Objects were sent to the 20 specific sites and 42 individual CT scanners that were used in the study. The Test Objects were scanned over 17 months while the COPDGene study continued to recruit subjects. A mixed linear effect statistical analysis of the CT scans on the 19 Test Objects was performed. The statistical model reflected influence of reconstruction kernels, tube current, individual Test Objects, CT scanner models, and temporal consistency on CT attenuation. Results: Depending on the Test Object material, there were significant differences between reconstruction kernels, tube current, individual Test Objects, CT scanner models, and temporal consistency. The two Test Object materials of most interest were lung equivalent foam and internal air. With lung equivalent foam, there were significant (p < 0.05) differences between the Siemens B31 (−856.6, ±0.82; mean ± SE) and the GE Standard (−856.6 ± 0.83) reconstruction kernel relative to the Siemens B35 reference standard (−852.5 ± 1.4). Comparing lung equivalent foam attenuation there were also significant differences between CT scanner models (p < 0.01), tube current (p < 0.005), and in temporal consistency (p

  11. 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.

  12. 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)

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. Memory hierarchy using row-based compression

    DOEpatents

    Loh, Gabriel H.; O'Connor, James M.

    2016-10-25

    A system includes a first memory and a device coupleable to the first memory. The device includes a second memory to cache data from the first memory. The second memory includes a plurality of rows, each row including a corresponding set of compressed data blocks of non-uniform sizes and a corresponding set of tag blocks. Each tag block represents a corresponding compressed data block of the row. The device further includes decompression logic to decompress data blocks accessed from the second memory. The device further includes compression logic to compress data blocks to be stored in the second memory.

  19. The evaluation and comparison of kidney length obtained from axial cuts in spiral CT scan with its true length

    PubMed Central

    Karami, Mehdi; Rahimi, Farshad; Tajadini, Mohammadhasan

    2015-01-01

    Background: Increased size of kidney is the main symptom of pyelonephritis and renal ischemia in children. Ultrasound and computed tomography (CT) scan methods are the imaging methods for evaluating the urogenital system. The aim of this study is to compare the kidney length obtained from spiral CT scan with the true length obtained from multi-slice CT. Materials and Methods: From 100 patients 200 kidneys were examined in Alzahra Hospital in 2012. Multi-slice CT was used to obtain coronal and sagittal cuts to find the length of kidneys. Results: The mean values of true size of axial sections of the right and left kidneys were 108.37 ± 12.3 mm and 109.74 ± 13.6 mm, respectively. The mean difference of axial sections’ lengths in the right and left kidneys was 1.37 ± 1.22 mm. The mean values of length in the spiral CT scan of the right and left kidneys were 98.61 ± 15.8 mm and 103.11 ± 15.9 mm, respectively. The difference in the estimated size by multi-slice CT scan in oblique and axial images was significant (9.77 ± 1.19 mm and 6.63 ± 0.8 mm for the right and left kidneys, respectively (P < 0.001). Conclusion: The average size of both kidneys determined in axial images was smaller than the actual size. The estimation of kidney size in axial images is not reliable, and to obtain the actual size, it is required to have the coronal and sagittal cuts with proper quality, which could be achieved by multi-slice method. PMID:25709984

  20. 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.

  1. Prospective versus retrospective ECG-gated 64-detector coronary CT angiography for evaluation of coronary artery bypass graft patency: comparison of image quality, radiation dose and diagnostic accuracy.

    PubMed

    Lee, Jae Hwan; Chun, Eun Ju; Choi, Sang Il; Vembar, Mani; Lim, Cheong; Park, Kay-Hyun; Choi, Dong-Ju

    2011-06-01

    We aimed to evaluate image quality, radiation dose and diagnostic accuracy of coronary CT angiography (CCTA) with a prospectively gated transverse-axial scan (PGT) compared with a retrospectively gated helical scan (RGH), using a 64-slice scanner in patients who underwent coronary artery bypass graft (CABG). Of the 131 consecutive patients that underwent CABG using 64-slice multidetector row computed tomography during 2008, patients with heart rate (HR) of <75 beats/minute (bpm), and HR variation <10 bpm were included in the study. PGT was performed on 39 patients with 93 grafts, with RGH performed on 43 patients with 102 grafts. Image quality (1: excellent-4: poor) and estimated radiation dose were compared between the two groups. Of these, a total of 64 segments in 26 patients were subjected to invasive coronary angiography (ICA) for clinical reasons. Diagnostic accuracy of CCTA for evaluation of graft was performed between the two groups with ICA as a reference standard in terms of significant stenosis (≥ 50% of luminal stenosis). The image quality was not statistically different in the two groups. Mean effective radiation dose was 6.5 mSv in PGT-group, which was significantly lower than that in the RGH-group (21.2 mSv; P < 0.001). There was no statistically significant difference in diagnostic accuracy between the two groups (PGT-group versus RGH-group; 93.1% versus 91.4%). PGT can achieve dose reductions of up to 70% compared to RGH while maintaining image quality and high diagnostic accuracy in patients undergoing CABG. PMID:21678128

  2. 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

  3. Factors affecting uncertainty in lung nodule volume estimation with CT: comparisons of findings from two estimation methods in a phantom study

    NASA Astrophysics Data System (ADS)

    Li, Qin; Gavrielides, Marios A.; Zeng, Rongping; Myers, Kyle J.; Sahiner, Berkman; Petrick, Nicholas

    2015-03-01

    This work aimed to compare two different types of volume estimation methods (a model-based and a segmentationbased method) in terms of identifying factors affecting measurement uncertainty. Twenty-nine synthetic nodules with varying size, radiodensity, and shape were placed in an anthropomorphic thoracic phantom and scanned with a 16- detector row CT scanner. Ten repeat scans were acquired using three exposures and two slice collimations, and were reconstructed with varying slice thicknesses. Nodule volumes were estimated from the reconstructed data using a matched-filter and a segmentation approach. Log transformed volumes were used to obtain measurement error with truth obtained through micro-CT. ANOVA and multiple linear regression were applied to measurement error to identify significant factors affecting volume estimation for each method. Root mean square of measurement errors (RMSE) for meaningful subgroups, repeatability coefficients (RC) for different imaging protocols, and reproducibility coefficients (RDC) for thin and thick collimation conditions were evaluated. Results showed that for both methods, nodule size, shape and slice thickness were significant factors. Collimation was significant for the matched-filter method. RMSEs for matched-filter measurements were in general smaller than segmentation. To achieve RMSE on the order of 15% or less for {5, 8, 9, 10mm} nodules, the corresponding maximum allowable slice thicknesses were {3, 5, 5, 5mm} for the matched-filter and {0.8, 3, 3, 3mm} for the segmentation method. RCs showed similar patterns for both methods, increasing with slice thickness. For 8-10mm nodules, the measurements were highly repeatable provided the slice thickness was ≤3mm, regardless of method and across varying acquisition conditions. RDCs were lower for thin collimation than thick collimation protocols. While RDC of matched filter volume estimation results was always lower than segmentation results, for 8-10mm nodules with thin

  4. 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.

  5. 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

  6. Chondroitin sulfate iron colloid-enhanced MR imaging in patients with hepatocellular carcinoma. Comparison with CT during arterial portography.

    PubMed

    Kamba, M; Suto, Y; Kato, T

    1994-11-01

    Chondroitin sulfate iron colloid (CSIC) was used as an MR contrast agent for the detection of hepatocellular carcinoma (HCC). The findings of 25 surgically confirmed HCCs in 19 patients were retrospectively analyzed. T1-, T2- and proton density-weighted spin echo MR images were obtained before and after i.v. injection of 23.6 microM Fe/kg of CSIC. Unenhanced and CSIC-enhanced MR images and images obtained by CT during arterial portography (CT-AP) were correlated with surgical pathology findings. The sensitivities of CSIC-enhanced and unenhanced MR imaging, and CT-AP were 92%, 80%, and 88%, respectively. No significant differences were noted. Portal flow abnormalities demonstrated by CT-AP did not affect the detection of HCC by CSIC-enhanced MR imaging. CSIC-enhancement at MR imaging was a disadvantage in the detection of lesions less than 1 cm in diameter. CSIC-enhanced MR imaging is a supplemental method for the detection of HCC.

  7. A comparison study of radiation exposure to patients during EVAR and Dyna CT in an angiosuite vs. an operating theatre.

    PubMed

    Bruschi, Andrea; Michelagnoli, Stefano; Chisci, Emiliano; Mazzocchi, Silvia; Panci, Simone; Didona, Annamaria; Ghirelli, Alessandro; Zatelli, Giovanna

    2015-03-01

    The aim of this study was to assess the patient dosimetric impact of endovascular abdominal aortic aneurysm repair (EVAR), both in an operating theatre (OR) and in an angiosuite (AS), with the facility of Dynamic CT (Dyna CT, Siemens AG, Berlin, Germany). One hundred and forty-six consecutive EVAR procedures dating from May 2011 to March 2013 were analysed. These were performed either in an OR (n = 97) using a mobile C-arm or in an AS (n = 49) equipped with a ceiling-mounted angiography system. Air kerma area product (P(KA)) and total air kerma at reference point (K(a,r)) values were reported for all procedures and Dyna CT. Radiation exposure during EVAR was quite low in the majority of patients but nearly 50 % higher if performed in AS vs. OR. Median Dyna CT K(a,r) was the same as an entire EVAR procedure in OR. The higher patient's radiation exposure recorded in the AS should be balanced with the technical advantages given to the EVAR procedure.

  8. 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

  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. 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…

  11. 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

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

    PubMed

    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.

  14. 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

  15. Volume doubling time of lung cancers detected in a chest radiograph mass screening program: Comparison with CT screening

    PubMed Central

    KANASHIKI, MAKI; TOMIZAWA, TAKUJI; YAMAGUCHI, IWAO; KURISHIMA, KOICHI; HIZAWA, NOBUYUKI; ISHIKAWA, HIROICHI; KAGOHASHI, KATSUNORI; SATOH, HIROAKI

    2012-01-01

    The aim of this study was to evaluate the volume doubling time (VDT) of lung cancer detected in our annual chest radiograph screening program and to compare it with those previously reported for computed tomography (CT) screening. In total, 209 patients who had a measurable tumor shadow and a history of participating in our chest radiograph mass screening program between 2006 and 2009 were included in this study. Indirect roentgenograms for patients with lung cancer were converted into digital images, and the section showing the tumor was enlarged on the monitor to a size of 0.01 mm. The mean VDT for all the patients was 158 days. Only 3.8% of the patients had a VDT of more than 400 days. In 140 patients with adenocarcinoma, the mean VDT was 177 days, and 5.0% of these patients had a VDT of more than 400 days. In the 44 patients with squamous cell carcinoma, the mean VDT was 133 days, and only 2.3% of these patients had a VDT of more than 400 days. These results were different from those previously reported for CT screening. In several reports on CT screening, more than 20% of the lung cancers had VDTs of more than 400 days. Since it is common knowledge that there are ‘indolent’ lung cancers with a VDT of more than 400 days, screening by annual chest radiography with rare overdiagnosis may need to be reconsidered. PMID:22970048

  16. 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)

  17. 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

  18. 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.

  19. An in vitro CT Comparison of Gutta-Percha Removal with Two Rotary Systems and Hedstrom Files

    PubMed Central

    Yadav, Pankaj; Bharath, Makonahalli Jaganath; Sahadev, Chickmagravalli Krishnegowda; Makonahalli Ramachandra, Praveen Kumar; Rao, Yogesh; Ali, Ambereen; Mohamed, Shahnawaz

    2013-01-01

    Introduction To evaluate the efficacy of NiTi mechanical rotary instrumentation and Hedstrom file for gutta-percha/sealer removal computed tomography (CT) was utilized in vitro. Materials and Methods Thirty extracted human single rooted teeth, each with a single canal were selected. The samples were decoronated with a double faced diamond disk to have 17-mm root; teeth roots were instrumented with K-files up to master apical file #30 using step back technique. Samples were obturated using cold lateral condensation of gutta-percha and AH Plus root canal sealer. The teeth were then randomly divided into three groups of 10 specimens each. After 2 weeks 3-dimensional images of the roots were obtained by CT and the volume of root filling mass was measured. All the canals were then retreated by either the ProTaper retreatment files, Mtwo retreatment files or Hedstrom files. The canals were irrigated with 2 mL of 2.5% sodium hypochlorite irrigating solution during each change of instrument. The volume of remaining filling materials after the retreatment procedures was assessed by CT. Statistical analysis was performed with one-way ANOVA and Tukey’s post hoc test. Results Neither of studied systems completely removed the root filling material. No significant difference was observed between the rotary systems. The volume of remaining filling materials was significantly less in rotary instrumentation than hand files. There was no significant difference for debris extruded from the apical foramen between the groups. Conclusion Under the experimental conditions, Mtwo and ProTaper retreatment files left less gutta-percha and sealer than H files; however, complete removal of filling materials was not achieved by the three systems investigated. PMID:23717331

  20. 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

  1. 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.

  2. 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).

  3. Patient-specific models of wall stress in abdominal aortic aneurysm: a comparison between MR and CT

    NASA Astrophysics Data System (ADS)

    de Putter, Sander; Breeuwer, Marcel; van de Vosse, Frans N.; Kose, Ursula; Gerritsen, Frans A.

    2006-03-01

    Finite element method based patient-specific wall stress in abdominal aortic aneurysm (AAA) may provide a more accurate rupture risk predictor than the currently used maximum transverse diameter. In this study, we have investigated the sensitivity of the wall stress in AAA with respect to geometrical variations. We have acquired MR and CT images for four patients with AAA. Three individual users have delineated the AAA vessel wall contours on the image slices. These contours were used to generate synthetic feature images for a deformable model based segmentation method. We investigated the reproducibility and the influence of the user variability on the wall stress. For sufficiently smooth models of the AAA wall, the peak wall stress is reproducible for three out of the four AAA geometries. The 0.99 percentiles of the wall stress show excellent reproducibility for all four AAAs. The variations induced by user variability are larger than the errors caused by the segmentation variability. The influence of the user variability appears to be similar for MR and CT. We conclude that the peak wall stress in AAA is sensitive to small geometrical variations. To increase reproducibility it appears to be best not to allow too much geometrical detail in the simulations. This could be achieved either by using a sufficiently smooth geometry representation or by using a more robust statistical parameter derived from the wall stress distribution.

  4. 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.

  5. Diagnostic capability of gadoxetate disodium-enhanced liver MRI for diagnosis of hepatocellular carcinoma: comparison with multi-detector CT.

    PubMed

    Toyota, Naoyuki; Nakamura, Yuko; Hieda, Masashi; Akiyama, Naoko; Terada, Hiroaki; Matsuura, Noriaki; Nishiki, Masayo; Kono, Hirotaka; Kohno, Hiroshi; Irei, Toshimitsu; Yoshikawa, Yukinobu; Kuraoka, Kazuya; Taniyama, Kiyomi; Awai, Kazuo

    2013-09-01

    The purpose of this study was to evaluate the diagnostic capability of gadoxetate disodium (Gd-EOB)-MRI for the detection of hepatocellular carcinoma (HCC) compared with multidetector CT (MDCT). Fifty patients with 57 surgically proven HCCs who underwent Gd-EOB-MRI and MDCT from March 2008 to June 2011 were evaluated. Two observers evaluated MR and CT on a lesion-by-lesion basis. We analyzed sensitivity by grading on a 5-point scale, the degree of arterial enhancement and the differences in histological grades in the diffusion-weighted images (DWI). The results showed that the sensitivity of Gd-EOB-MRI was higher than that of MDCT especially for HCCs that were 1 cm in diameter or smaller. The hepatobiliary phase was useful for the detecting of small HCC. We had few cases in which it was difficult to judge HCC in the arterial enhancement between MRI and MDCT. In the diffusion-weighted image, well differentiated HCC tended to show a low signal intensity, and poorly differentiated HCC tended to show a high signal intensity. In moderately differentiated HCC's, the mean diameter of the high signal intensity group was larger than that of the low signal intensity group (24.5 mm vs. 15.8 mm). In conclusion, Gd-EOB-MRI tended to show higher sensitivity compared to MDCT in the detection of HCC.

  6. 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.

  7. 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.

  8. Preoperative staging of colorectal cancer: CT vs. integrated FDG PET/CT.

    PubMed

    Shin, Sang Soo; Jeong, Yong Yeon; Min, Jung Jun; Kim, Hyeong Rok; Chung, Tae Woong; Kang, Heoung Keun

    2008-01-01

    Accurate preoperative staging is essential in determining the optimal therapeutic planning for individual patients. The computed tomography (CT) in the preoperative staging of colorectal cancer, even if controversial, may be useful for planning surgery and/or neoadjuvant therapy, particularly when local tumor extension into adjacent organs or distant metastases are detected. There have been significant changes in the CT technology with the advent of multi-detector row CT (MDCT) scanner. Advances in CT technology have raised interest in the potential role of CT for detection and staging of colorectal cancer. In recent studies, MDCT with MPR images has shown promising accuracy in the evaluation of local extent and nodal involvement of colorectal cancer. Combined PET/CT images have significant advantages over either alone because it provides both functional and anatomical data. Therefore, it is natural to expect that PET/CT would improve the accuracy of preoperative staging of colorectal cancer. The most significant additional information provided by PET/CT relates to the accurate detection of distant metastases. For the evaluation of patients with colorectal cancer, CT has relative advantages over PET/CT in regard to the depth of tumor invasion through the wall, extramural extension, and regional lymph node metastases. PET/CT should be performed on selected patients with suggestive but inconclusive metastatic lesions with CT. In addition, PET/CT with dedicated CT protocols, such as contrast-enhanced PET/CT and PET/CT colonography, may replace the diagnostic CT for the preoperative staging of colorectal cancer.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. The Use of Contrast-Enhanced Post Mortem CT in the Detection of Cardiovascular Deaths

    PubMed Central

    Penzkofer, Tobias; Kuhl, Christiane Katharina; Knüchel, Ruth; Mahnken, Andreas H.

    2014-01-01

    Objectives To evaluate the diagnostic value of contrast enhanced post mortem computed tomography (PMCT) in comparison to non-enhanced post mortem CT in the detection of cardiovascular causes of death (COD). Background As autopsy rates decline, new methods to determine CODs are necessary. So contrast enhanced PMCT shall be evaluated in comparison to established non-enhanced PMCT in order to further improve the method. Methods In a prospective study, 20 corpses were examined using a 64-row multisclice CT (MSCT) before and after intraarterial perfusion with a newly developed, barium-bearing contrast agent and ventilation of the lungs. The cause of death was determined in enhanced and unenhanced scans and a level of confidence (LOC) was given by three experienced radiologists on a scale between 0 and 4. Results were compared to autopsy results as gold standard. Autopsy was performed blinded to PMCT-findings. Results The method allowed visualization of different types of cause of death. There was a significant improvement in LOC in enhanced scans compared to unenhanced scans as well as an improvement in the detection of COD. The cause of death could be determined in 19 out of 20 patients. Conclusions PMCT is feasible and appears to be robust for diagnosing cardiovascular causes of death. When compared with unenhanced post-mortem CT intraarterial perfusion and pulmonary ventilation significantly improve visualization and diagnostic accuracy. These promising results warrant further studies. PMID:24759757

  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. CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP

    PubMed Central

    Laqmani, Azien; Kurfürst, Maximillian; Butscheidt, Sebastian; Sehner, Susanne; Schmidt-Holtz, Jakob; Behzadi, Cyrus; Nagel, Hans Dieter; Adam, Gerhard; Regier, Marc

    2016-01-01

    Purpose To assess image quality of CT pulmonary angiography (CTPA) at reduced radiation exposure (RD-CTPA) and contrast medium (CM) volume using two different iterative reconstruction (IR) algorithms (iDose4 and iterative model reconstruction (IMR)) in comparison to filtered back projection (FBP). Materials and Methods 52 patients (body weight < 100 kg, mean BMI: 23.9) with suspected pulmonary embolism (PE) underwent RD-CTPA (tube voltage: 80 kV; mean CTDIvol: 1.9 mGy) using 40 ml CM. Data were reconstructed using FBP and two different IR algorithms (iDose4 and IMR). Subjective and objective image quality and conspicuity of PE were assessed in central, segmental, and subsegmental arteries. Results Noise reduction of 55% was achieved with iDose4 and of 85% with IMR compared to FBP. Contrast-to-noise ratio significantly increased with iDose4 and IMR compared to FBP (p<0.05). Subjective image quality was rated significantly higher at IMR reconstructions in comparison to iDose4 and FBP. Conspicuity of central and segmental PE significantly improved with the use of IMR. In subsegmental arteries, iDose4 was superior to IMR. Conclusions CTPA at reduced radiation exposure and contrast medium volume is feasible with the use of IMR, which provides improved image quality and conspicuity of pulmonary embolism in central and segmental arteries. PMID:27611448

  18. 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

  19. 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

  20. Development and Evaluation of a Combined Cultivator and Band Sprayer with a Row-Centering RTK-GPS Guidance System

    PubMed Central

    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. 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.

  2. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

  3. 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)

  4. 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.

  5. 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

  6. [Intra-articular calcaneus fracture. Classification in CT as a prerequisite for therapeutic decision and quantitative comparison].

    PubMed

    Brunner, U; Kenn, R W; Slawik, J; Schweiberer, L

    1992-07-01

    Whether conservative or operative management is selected for intra-articular fractures of the os calcis depends on subjective factors and on the surgeon's experience. There is no classification available that allows ranking of such fractures according to the extent of destruction and the degree of dislocation at the same time. CT scans of 44 calcaneal fractures have been used to elaborate a new classification system for calcaneal surfaces. According to the involvement of joint surfaces, especially of the posterior facet, the degree of dislocation and the number of fragments of the posterior facet, six classes are defined. Within each class of fracture, the formation of "steps" in the posterior facet, widening of the heel, loss of height and deviation of axes are quantified. The new classification provides an instrument for use in the evaluation of joint destruction and dislocation. It helps to provide an objective basis for decisions between functional treatment and open reduction with internal fixation and for prospective analysis of fracture treatment.

  7. 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

  8. Accuracy and feasibility of optoelectronic sensors for weed mapping in wide row crops.

    PubMed

    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.

  9. 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

  10. Percutaneous CT-Guided Biopsy of the Lung: Comparison Between Aspiration and Automated Cutting Needles Using a Coaxial Technique

    SciTech Connect

    Laurent, Francois; Latrabe, Valerie; Vergier, Beatrice; Michel, Philippe

    2000-07-15

    Purpose: To compare the accuracy and complication rate of two different CT-guided transthoracic needle biopsy techniques: fine needle aspiration and an automated biopsy device.Methods: Two consecutive series of respectively 125 (group A) and 98 (group B) biopsies performed using 20-22 gauge coaxial fine needle aspiration (group A) and an automated 19.5 gauge coaxial biopsy device (group B) were compared in terms of their accuracy and complication rate.Results: Groups A and B included respectively 100 (80%) and 77 (79%) malignant lesions and 25 (20%) and 18 (21%) benign lesions. No significant difference was found between the two series concerning patients, lesions, and procedural variables. For a diagnosis of malignancy, a statistically significant difference in sensitivity was found (82.7% vs 97.4%) between results obtained with the automated biopsy device and fine needle aspiration respectively. For a diagnosis of malignancy, the false negative rate of the biopsy result was significantly higher (p <0.005) in group A (17%) than in group B (2.6%). For a specific diagnosis of benignity, no statistically significant difference was found between the two groups (44% vs 26%) but the automated biopsy device provided fewer indeterminate cases. There was no difference between the two groups concerning the pneumothorax rate, which was 20% in group A and 15% in group B, or the hemoptysis rate, which was 2.4% in group A and 4% in group B.Conclusion: For a diagnosis of malignancy when a cytopathologist is not available on-site, automated biopsy devices provide a lower rate of false negative results and a similar complication rate to fine needle aspiration.

  11. 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.

  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. 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.

  14. A row-by-row off-design performance calculation method for turbines

    NASA Technical Reports Server (NTRS)

    Schobeiri, T.; Abouelkheir, M.

    1991-01-01

    The turbine component of a gas turbine engine is frequently subjected to extreme operation conditions associated with significant changes in mass flow, turbine inlet temperature, pressure and rotational speed. These off-design operation conditions significantly affect the flow deflection within the turbine stage, which consists of individual stator and rotor rows. As a result, the stage parameters representing the velocity diagram will change and affect the efficiency and performance of the stage and, thus, the turbine. A row-by-row calculation method is presented for predicting the performance behavior of turbines under extreme off-design conditions. The method is applied to a multistage turbine for which the off-design performance is calculated and compared with the measurement.

  15. 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.

  16. 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.

  17. 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.

  18. Standardized CT protocols and nomenclature: better, but not yet there.

    PubMed

    Singh, Sarabjeet; Kalra, Mannudeep K

    2014-10-01

    Radiation dose associated with CT is an important safety concern in patient care, especially in children. Technical advancements in multidetector-row CT scanner technology offer several advantages for clinical applications; these advancements have considerably increased CT utilization and enhanced the complexity of CT scanning protocols. Furthermore there are several scan manufacturers spearheading these technical advancements, leading to different commercial names causing confusion among the users, especially at imaging sites with scanners from different vendors. Several scientific studies and the National Council on Radiation Protection and Measurements (NCRP) have shown variation in CT radiation doses for same body region and similar scanning protocols. Therefore there is a need for standardization of scanning protocols and nomenclature of scan parameters. The following material reviews the status and challenges in standardization of CT scanning and nomenclature. PMID:25304702

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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

  5. An analytical study of the effect of coolant flow variables on the kinetic energy output of a cooled turbine blade row.

    NASA Technical Reports Server (NTRS)

    Prust, H. W., Jr.

    1972-01-01

    Demonstration that the change in output of a cooled turbine blade row relative to the specific output of the uncooled blade row can be positive, negative, or zero, depending on the velocity, injection location, injection angle, and temperature of the coolant. Comparisons between the analytical results and experimental results for four different cases of coolant discharge, all at a coolant temperature ratio of unity, show good agreement for three cases, and rather poor agreement for the other.

  6. 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

  7. A comparison of the psychological burden of PET/MRI and PET/CT scans and association to initial state anxiety and previous imaging experiences

    PubMed Central

    Neriman, D; Hoath, J; Millner, L; Endozo, R; Azzopardi, G; O'Meara, C; Bomanji, J; Groves, A M

    2015-01-01

    Objective: To investigate the level of psychological burden experienced by patients undergoing positron emission tomography (PET)/MRI scanning compared with PET/CT. Methods: 100 adult patients referred for PET/CT and underwent PET/MRI scanning were eligible. Initial state, psychological burden of PET/CT and PET/MRI, scan satisfaction and preference were assessed using a purpose-designed questionnaire, comprising 61 five-point Likert scale questions and a three-point tick box question indicating preference between PET/CT and PET/MRI. State anxiety was assessed using the state portion of the State Trait Anxiety Inventory. Wilcoxon signed-rank tests compared psychological burden experienced by participants following PET/CT and PET/MRI scan. Results: A greater level of psychological burden was experienced by patients during PET/MRI than PET/CT p ≤ 0.001, consistent with patients' preference for PET/CT over PET/MRI (p = 0.013). There was a significant relationship between PET/CT psychological burden and initial state (r = 0.386, p ≤ 0.001). No significant relationship was identified between Initial state and psychological burden of PET MRI (r = −0.089; p = 217). There was a significant relationship between psychological burden of PET/CT and PET/MRI (r = 0.354; p = 0.001). Conclusion: Patients' experience increased psychological burden during PET/MRI compared with PET/CT. Previous scanning experiences and patients' interactions prior to and during PET/MRI improved patient satisfaction. Interventions could be implemented to improve imaging outcome. Advances in knowledge: This study provides evidence for the increased psychological burden of PET/MRI compared with PET/CT, and that people prefer the PET/CT procedure. We have shown that the patients who expressed a preference for PET/MRI demonstrated significantly lower psychological burden for that procedure than those that preferred PET/CT, which indicates that the benefit of reduced

  8. 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

  9. 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.

  10. 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

  11. 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

  12. 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

  13. Using SNOMED CT to identify a crossmap between two classification systems: a comparison with an expert-based and a data-driven strategy.

    PubMed

    Bakhshi-Raiez, Ferishta; Cornet, Ronald; Bosman, Rob J; Joore, Hans; de Keizer, Nicolette F

    2010-01-01

    A crossmap between successive versions of classification systems is necessary to maintain the continuity of health care documentation. A reference terminology can serve as an intermediary to support this task. Within this study we evaluated the use of SNOMED CT to create a crossmap between two versions of an intensive care classification system. Firstly, the SNOMED CT crossmap was compared with an expert-based and a data-driven crossmap. Next, the influence of these crossmap strategies on the health care outcome was evaluated. For 50% of the analyzed cases, the three mapping strategies resulted in the same crossmaps. In other cases, there was an overlap between the SNOMED CT crossmaps and the crossmaps provided by one of the two other strategies. Differences in the crossmap results had however no significant influence on the health care outcomes. SNOMED CT can be used as an intermediary to solve the problem of crossmapping between versions of classification systems.

  14. In vivo micro-CT imaging of untreated and irradiated orthotopic glioblastoma xenografts in mice: capabilities, limitations and a comparison with bioluminescence imaging.

    PubMed

    Kirschner, Stefanie; Felix, Manuela C; Hartmann, Linda; Bierbaum, Miriam; Maros, Máté E; Kerl, Hans U; Wenz, Frederik; Glatting, Gerhard; Kramer, Martin; Giordano, Frank A; Brockmann, Marc A

    2015-04-01

    Small animal imaging is of increasing relevance in biomedical research. Studies systematically assessing the diagnostic accuracy of contrast-enhanced in vivo micro-CT of orthotopic glioma xenografts in mice do not exist. NOD/SCID/γc(-/-) mice (n = 27) underwent intracerebral implantation of 2.5 × 10(6) GFP-Luciferase-transduced U87MG cells. Mice underwent bioluminescence imaging (BLI) to detect tumor growth and afterwards repeated contrast-enhanced (300 µl Iomeprol i.v.) micro-CT imaging (80 kV, 75 µAs, 360° rotation, 1,000 projections, 33 s scan time, resolution 40 × 40 × 53 µm, 0.5 Gy/scan). Presence of tumors, tumor diameter and tumor volume in micro-CT were rated by two independent readers. Results were compared with histological analyses. Six mice with tumors confirmed by micro-CT received fractionated irradiation (3 × 5 Gy every other day) using the micro-CT (5 mm pencil beam geometry). Repeated micro-CT scans were tolerated well. Tumor engraftment rate was 74 % (n = 20). In micro-CT, mean tumor volume was 30 ± 33 mm(3), and the smallest detectable tumor measured 360 × 620 µm. The inter-rater agreement (n = 51 micro-CT scans) for the item tumor yes/no was excellent (Spearman-Rho = 0.862, p < 0.001). Sensitivity and specificity of micro-CT were 0.95 and 0.71, respectively (PPV = 0.91, NPV = 0.83). BLI on day 21 after tumor implantation had a sensitivity and specificity of 0.90 and 1.0, respectively (PPV = 1.0, NPV = 0.5). Maximum tumor diameter and volume in micro-CT and histology correlated excellently (tumor diameter: 0.929, p < 0.001; tumor volume: 0.969, p < 0.001, n = 17). Irradiated animals showed a large central tumor necrosis. Longitudinal contrast enhanced micro-CT imaging of brain tumor growth in live mice is feasible at high sensitivity levels and with excellent inter-rater agreement and allows visualization of radiation effects.

  15. Development and Validation of a Simple Conversion Model for Comparison of Intracerebral Hemorrhage Volumes Measured on CT and Gradient Recalled Echo MRI

    PubMed Central

    Burgess, Richard E.; Warach, Steven; Schaewe, Timothy J.; Copenhaver, Brittany R.; Alger, Jeffry R.; Vespa, Paul; Martin, Neil; Saver, Jeffrey L.; Kidwell, Chelsea S.

    2009-01-01

    Background and Purpose Gradient recalled echo MRI (GRE) has been shown to be as accurate as CT for the detection of acute intracerebral hemorrhage (ICH). However, because of the differences in the signal parameter being detected, apparent hemorrhage size is expected to vary by imaging modality, with GRE providing larger volumes attributable to susceptibility effects. Methods Image data from patients participating in 3 ICH studies were retrospectively reviewed. Patients with acute ICH were included if (1) concurrent MRI and CT were performed within 72 hours of symptom onset, and (2) each modality was performed within 240 minutes of each other. ICH volumes were calculated using a semiautomated image analysis program. The least squares method was used to develop a conversion equation based on a linear regression of GRE volume on CT volume. Results Thirty-six patients met inclusion criteria. MRI was performed first in 18, CT first in 18. Mean hemorrhage volume was 25.2cc (range 0.1 to 83.9cc) on CT and 32.7cc (range 0.1 to 98.7cc) measured on GRE. A linear relationship defined by CT Volume=GRE Volume*0.8 (Spearman’s correlation coefficient=0.992, P<0.001) was derived. Conclusions Acute ICH volumes as measured on GRE pulse sequences are consistently larger than CT volumes. A simple mathematical conversion model has been developed: CT volume=0.8*GRE volume. This formula can be used in studies using both imaging modalities, across different studies, or to track ICH growth over time independent of imaging modality in an individual patient. PMID:18483414

  16. 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.

  17. Canadian CT head rule and New Orleans Criteria in mild traumatic brain injury: comparison at a tertiary referral hospital in Japan.

    PubMed

    Mata-Mbemba, Daddy; Mugikura, Shunji; Nakagawa, Atsuhiro; Murata, Takaki; Kato, Yumiko; Tatewaki, Yasuko; Takase, Kei; Kushimoto, Shigeki; Tominaga, Teiji; Takahashi, Shoki

    2016-01-01

    We compared Canadian computed tomography (CT) head rule (CCHR) and New Orleans Criteria (NOC) in predicting important CT findings in patients with mild traumatic brain injury (TBI). We included 142 consecutive patients with mild TBI [Glasgow coma scale (GCS) 13-15] who showed at least one of the risk factors stated in the CCHR or the NOC. We introduced two scores: a Canadian from the CCHR and a New Orleans from the NOC. A patient's score represented a sum of the number of positive items. We examined the relationship between scores or items and the presence of important CT findings. Only the Canadian was significantly associated with important CT findings in multivariate analyses and showed higher area under the receiver operating characteristic curve (AUC) either in all 142 patients (GCS 13-15: P = 0.0130; AUC = 0.69) or in the 67 with a GCS = 15 (P = 0.0128, AUC = 0.73). Of items, ">60 years" or "≥65 years" included in either guideline was the strongest predictor of important CT finding, followed by "GCS < 15 after 2 h" included only in the CCHR. In a tertiary referral hospital in Japan, CCHR had higher performance than the NOC in predicting important CT findings. PMID:27026873

  18. 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

  19. 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.

  20. Comparison of 18F-FDG PET/CT, MRI and SPECT in the diagnosis of local residual/recurrent nasopharyngeal carcinoma: A meta-analysis.

    PubMed

    Wei, Junbao; Pei, Su; Zhu, Xiaodong

    2016-01-01

    The objective of this study was to assess the overall diagnostic value of MRI, SPECT and 18F-FDG PET/CT in detecting local NPC residual/recurrence with a meta-analysis. We performed a systematic review with meta-analyses to compare the diagnostic performance of nuclear magnetic resonance Imaging (MRI), single photon emission computed tomography (SPECT) and 18-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET/CT) as imaging modalities for the detection of local residual or recurrent nasopharyngeal carcinoma (NPC). MEDLINE, EMBASE and publisher databases were searched in December 2014. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Pooled estimation and subgroup analysis data were obtained by statistical analysis. Seventeen studies were included in the meta-analysis. The pooled sensitivity estimates for 18F-FDGPET/CT (90%) and SPECT (85%) were not significantly higher than MRI (77%) (p=0.096 and 0.164, respectively). The pooled specificity estimates for 18F-FDGPET/CT (93%) and SPECT (81%) were significantly higher than MRI (76%) (p=0.033 and 0.042, respectively). The pooled DOR (Diagnostic odds ratio) estimates for 18F-FDGPET/CT (73.27) were significantly higher than MRI (12.09) (p=0.019) while the pooled DOR estimates for SPECT (78.69) were not significantly higher than MRI (12.09) (p=0.872). For 18F-FDGPET/CT, there were no significant differences between PET-CT and PET on all of the variables including sensitivity, specificity, PLR (Positive likelihood ratio), NLR (Negative likelihood ratio) and DOR (P>0.05). For SPECT, there were no significant differences between 201TI-SPECT and MIBI-SPECT on all of the variables including sensitivity, specificity, PLR, NLR and DOR (P>0.05). Both 18F-FDGPET/CT and SPECT are very accurate for the detection of local residual or recurrent NPC, they are superior to MRI in distinguishing recurrent NPC from fibrosis or scar tissue after RT in irradiated

  1. 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

  2. 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

  3. The adaptive statistical iterative reconstruction-V technique for radiation dose reduction in abdominal CT: comparison with the adaptive statistical iterative reconstruction technique

    PubMed Central

    Cho, Jinhan; Oh, Jongyeong; Kim, Dongwon; Cho, Junghyun; Kim, Sanghyun; Lee, Sangyun; Lee, Jihyun

    2015-01-01

    Objective: To investigate whether reduced radiation dose abdominal CT images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V) compromise the depiction of clinically competent features when compared with the currently used routine radiation dose CT images reconstructed with ASIR. Methods: 27 consecutive patients (mean body mass index: 23.55 kg m−2 underwent CT of the abdomen at two time points. At the first time point, abdominal CT was scanned at 21.45 noise index levels of automatic current modulation at 120 kV. Images were reconstructed with 40% ASIR, the routine protocol of Dong-A University Hospital. At the second time point, follow-up scans were performed at 30 noise index levels. Images were reconstructed with filtered back projection (FBP), 40% ASIR, 30% ASIR-V, 50% ASIR-V and 70% ASIR-V for the reduced radiation dose. Both quantitative and qualitative analyses of image quality were conducted. The CT dose index was also recorded. Results: At the follow-up study, the mean dose reduction relative to the currently used common radiation dose was 35.37% (range: 19–49%). The overall subjective image quality and diagnostic acceptability of the 50% ASIR-V scores at the reduced radiation dose were nearly identical to those recorded when using the initial routine-dose CT with 40% ASIR. Subjective ratings of the qualitative analysis revealed that of all reduced radiation dose CT series reconstructed, 30% ASIR-V and 50% ASIR-V were associated with higher image quality with lower noise and artefacts as well as good sharpness when compared with 40% ASIR and FBP. However, the sharpness score at 70% ASIR-V was considered to be worse than that at 40% ASIR. Objective image noise for 50% ASIR-V was 34.24% and 46.34% which was lower than 40% ASIR and FBP. Conclusion: Abdominal CT images reconstructed with ASIR-V facilitate radiation dose reductions of to 35% when compared with the ASIR. Advances in knowledge: This study represents the first

  4. 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

  5. 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.

  6. 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

  7. Contrast-Enhanced Ultrasound (CEUS) for Echographic Detection of Hepato Cellular Carcinoma in Cirrhotic Patients Previously Treated with Multiple Techniques: Comparison of Conventional US, Spiral CT and 3-Dimensional CEUS with Navigator Technique (3DNav CEUS).

    PubMed

    Giangregorio, Francesco

    2011-01-01

    A commercially available technique named "NAVIGATOR" (Esaote, Italy) easily enables a 3-D reconstruction of a single 2-D acquisition of Contrast Enhanced Ultrasound (CEUS) imaging of the whole liver (with a volumetric correction thanks to the electromagnetic device of NAVIGATOR). Aim of the study was to evaluate this "panoramic" technique in comparison with conventional US and spiral CT in the detection of new hepatic lesions. 144 cirrhotic patients (previously treated for hepato cellular carcinoma (HCC)) in follow-up with detection of 98 new nodules (N), 28 multinodular (Nmulti), 14 loco-regional regrowth (LR) 94 efficaciously treated without new nodules (neg) and four multinodular without new nodules, were submitted to 200 examinations with this new technique from November 2008 to November 2009. 3DNavCEUS was performed using SonoVue (Bracco), as contrast agent, and a machine (Technos MPX, Esaote). Spiral CT and 3DNav CEUS were performed in the same month during follow up. Sens.,Spec.,diagn.-Acc.,PPV and NPV were evaluated; comparison and differences between the techniques were obtained with chi-square (SPSS release-15). Final diagnosis was: 98 new lesions (N) (one to three), 28 multinodular HCC (Nmulti) and 14 loco-regional regrowth (LR); in 94 no more lesions were observed during follow-up; conventional US obtained: 58 N (+18 multinodularN and 8 LR), 40 false negative (+10 Nmulti and 6 LR) (sens:59.2, spec:100%, Diagn Accur:73.6, PPV:100; NPV:70.1); spiral CT obtained: 84N (+26-multinodularN and 14-LR), 14 false-negative (+2-Nmulti), and one false-positive (sens:85.7, spec:97.9%, Diagn Accur:90.9, PPV:97.7; NPV:86.8); 3DNAV obtained: 92N (+28 multinodularN and 14LR), 6 false-negative, and two false-positives (sens:93.9, spec:97.9%, Diagn Accur:95.6, PPV:97.9; NPV:93.9). 3-DNav CEUS is significantly better than US and almost similar to spiral CT for detection of new HCC. This technique, in particular, showed the presence of lesions even in the cases not detected

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. CT virtual endoscopy and 3D stereoscopic visualisation in the evaluation of coronary stenting.

    PubMed

    Sun, Z; Lawrence-Brown

    2009-10-01

    The aim of this case report is to present the additional value provided by CT virtual endoscopy and 3D stereoscopic visualisation when compared with 2D visualisations in the assessment of coronary stenting. A 64-year old patient was treated with left coronary stenting 8 years ago and recently followed up with multidetector row CT angiography. An in-stent restenosis of the left coronary artery was suspected based on 2D axial and multiplanar reformatted images. 3D virtual endoscopy was generated to demonstrate the smooth intraluminal surface of coronary artery wall, and there was no evidence of restenosis or intraluminal irregularity. Virtual fly-through of the coronary artery was produced to examine the entire length of the coronary artery with the aim of demonstrating the intraluminal changes following placement of the coronary stent. In addition, stereoscopic views were generated to show the relationship between coronary artery branches and the coronary stent. In comparison with traditional 2D visualisations, virtual endoscopy was useful for assessment of the intraluminal appearance of the coronary artery wall following coronary stent implantation, while stereoscopic visualisation improved observers' understanding of the complex cardiac structures. Thus, both methods could be used as a complementary tool in cardiac imaging.

  14. 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

  15. 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

  16. Myocardial CT Perfusion Imaging and SPECT for the Diagnosis of Coronary Artery Disease: A Head-to-Head Comparison from the CORE320 Multicenter Diagnostic Performance Study

    PubMed Central

    Mehra, Vishal C.; Chen, Marcus Y.; Kitagawa, Kakuya; Arbab-Zadeh, Armin; Miller, Julie M.; Matheson, Matthew B.; Vavere, Andrea L.; Kofoed, Klaus F.; Rochitte, Carlos E.; Dewey, Marc; Yaw, Tan S.; Niinuma, Hiroyuki; Brenner, Winfried; Cox, Christopher; Clouse, Melvin E.; Lima, João A. C.; Di Carli, Marcelo

    2014-01-01

    Purpose To compare the diagnostic performance of myocardial computed tomographic (CT) perfusion imaging and single photon emission computed tomography (SPECT) perfusion imaging in the diagnosis of anatomically significant coronary artery disease (CAD) as depicted at invasive coronary angiography. Materials and Methods This study was approved by the institutional review board. Written informed consent was obtained from all patients. Sixteen centers enrolled 381 patients from November 2009 to July 2011. Patients underwent rest and adenosine stress CT perfusion imaging and rest and either exercise or pharmacologic stress SPECT before and within 60 days of coronary angiography. Images from CT perfusion imaging, SPECT, and coronary angiography were interpreted at blinded, independent core laboratories. The primary diagnostic parameter was the area under the receiver operating characteristic curve (Az). Sensitivity and specificity were calculated with use of prespecified cutoffs. The reference standard was a stenosis of at least 50% at coronary angiography as determined with quantitative methods. Results CAD was diagnosed in 229 of the 381 patients (60%). The per-patient sensitivity and specificity for the diagnosis of CAD (stenosis ≥50%) were 88% (202 of 229 patients) and 55% (83 of 152 patients), respectively, for CT perfusion imaging and 62% (143 of 229 patients) and 67% (102 of 152 patients) for SPECT, with Az values of 0.78 (95% confidence interval: 0.74, 0.82) and 0.69 (95% confidence interval: 0.64, 0.74) (P = .001). The sensitivity of CT perfusion imaging for single- and multivessel CAD was higher than that of SPECT, with sensitivities for left main, three-vessel, two-vessel, and one-vessel disease of 92%, 92%, 89%, and 83%, respectively, for CT perfusion imaging and 75%, 79%, 68%, and 41%, respectively, for SPECT. Conclusion The overall performance of myocardial CT perfusion imaging in the diagnosis of anatomic CAD (stenosis ≥50%), as demonstrated with the

  17. Simulated lesion, human observer performance comparison between thin-section dedicated breast CT images versus computed thick-section simulated projection images of the breast.

    PubMed

    Chen, L; Boone, J M; Abbey, C K; Hargreaves, J; Bateni, C; Lindfors, K K; Yang, K; Nosratieh, A; Hernandez, A; Gazi, P

    2015-04-21

    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. 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, 0.71, 1.5 and 2.9 mm were representative of breast CT; the average 43 mm slice thickness served to simulate simulated projection images of the breast.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 average physicist observer, however trends

  18. 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

  19. Comparison of extended field-of-view reconstructions in C-arm flat-detector CT using patient size, shape or attenuation information

    NASA Astrophysics Data System (ADS)

    Kolditz, Daniel; Meyer, Michael; Kyriakou, Yiannis; Kalender, Willi A.

    2011-01-01

    In C-arm-based flat-detector computed tomography (FDCT) it frequently happens that the patient exceeds the scan field of view (SFOV) in the transaxial direction because of the limited detector size. This results in data truncation and CT image artefacts. In this work three truncation correction approaches for extended field-of-view (EFOV) reconstructions have been implemented and evaluated. An FDCT-based method estimates the patient size and shape from the truncated projections by fitting an elliptical model to the raw data in order to apply an extrapolation. In a camera-based approach the patient is sampled with an optical tracking system and this information is used to apply an extrapolation. In a CT-based method the projections are completed by artificial projection data obtained from the CT data acquired in an earlier exam. For all methods the extended projections are filtered and backprojected with a standard Feldkamp-type algorithm. Quantitative evaluations have been performed by simulations of voxelized phantoms on the basis of the root mean square deviation and a quality factor Q (Q = 1 represents the ideal correction). Measurements with a C-arm FDCT system have been used to validate the simulations and to investigate the practical applicability using anthropomorphic phantoms which caused truncation in all projections. The proposed approaches enlarged the FOV to cover wider patient cross-sections. Thus, image quality inside and outside the SFOV has been improved. Best results have been obtained using the CT-based method, followed by the camera-based and the FDCT-based truncation correction. For simulations, quality factors up to 0.98 have been achieved. Truncation-induced cupping artefacts have been reduced, e.g., from 218% to less than 1% for the measurements. The proposed truncation correction approaches for EFOV reconstructions are an effective way to ensure accurate CT values inside the SFOV and to recover peripheral information outside the SFOV.

  20. 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

  1. 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

  2. 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

  3. 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

  4. Effect of BMI on knee joint torques in ergometer rowing.

    PubMed

    Roemer, Karen; Hortobagyi, Tibor; Richter, Chris; Munoz-Maldonado, Yolanda; Hamilton, Stephanie

    2013-12-01

    Although an authoritative panel recommended the use of ergometer rowing as a non-weight-bearing form of exercise for obese adults, the biomechanical characterization of ergometer rowing is strikingly absent. We examined the interaction between body mass index (BMI) relative to the lower extremity biomechanics during rowing in 10 normal weight (BMI 18-25), 10 overweight (BMI 25-30 kg·m⁻²), and 10 obese (BMI > 30 kg·m⁻²) participants. The results showed that BMI affects joint kinematics and primarily knee joint kinetics. The data revealed that high BMI leads to unfavorable knee joint torques, implying increased loads of the medial compartment in the knee joint that could be avoided by allowing more variable foot positioning on future designs of rowing ergometers.

  5. 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

  6. 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

  7. 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

  8. 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.

  9. Proximal row carpectomy with or without postoperative immobilisation.

    PubMed

    Jacobs, R; Degreef, I; De Smet, L

    2008-12-01

    Previously published reports have shown good results after proximal row carpectomy in all cases that had a postoperative immobilisation period from 1 to 4 weeks. Immobilisation is thought to be necessary because of the risk of postoperative subluxation of the carpus and for pain relief. There is, however, no evidence of its value. The results in 13 patients who underwent proximal row carpectomy without postoperative immobilisation were compared with those in 25 patients who underwent proximal row carpectomy with postoperative immobilisation for 4 weeks. After a mean follow-up period of 27 months, no significant differences were found for pain, range of motion or return to work between the two groups. We conclude that postoperative immobilisation is not necessary after proximal row carpectomy.

  10. 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

  11. 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

  12. 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

  13. 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

  14. Comparison of the accuracy of 99mTc-3P4-RGD2 SPECT and CT in diagnosing solitary pulmonary nodules

    PubMed Central

    Zhang, Haishan; Gao, Shi; Chen, Bin; Cheng, Guanghui

    2016-01-01

    The aim of the present study was to compare technetium-99m-(polyethylene glycol-4)3-(Arg-Gly-Asp)2 (99mTc-3P4-RGD2) single-photon emission computed tomography (SPECT) and computed tomography (CT) in the noninvasive differentiation of solitary pulmonary nodules (SPNs). The present study prospectively investigated a consecutive series of 24 patients with SPN, who were newly diagnosed using radiography between September 2012 and January 2014. All patients underwent 99mTc-3P4-RGD2 SPECT and CT scans using a dual-head variable-angle γ-camera equipped with high-resolution collimators. A blinded panel of two thoracic radiologists for CT and three nuclear physicians for SPECT analyzed the images using a 5-grade scale. The SPECT images were also semi-quantitatively evaluated using tumor to non-tumor localization ratios (T/NT). The results were verified by pathological examination of the biopsy material obtained from each patient with SPN, and receiver operating characteristic (ROC) curves were generated from these results. The present results revealed that there were 17 malignant and 7 benign SPNs among the 24 patients with SPN. The mean size of the SPN was 2.1±0.6 cm. Sensitivity of visual analysis for SPECT and CT were 100.0 and 82.4%, respectively, and specificity was 71.4% for the two methods. When the T/NT SPECT semiquantitative analysis (ratio, 1.64) was used as a cut-off, the sensitivity and specificity of SPECT were 100.0 and 71.4%, respectively. The areas under the ROC curves were 0.840 for visual analysis of SPECT [95% confidence interval (CI), 0.600–1.000], 0.849 for semiquantitative analysis of SPECT (95% CI, 0.618–1.000) and 0.815 for CT (95% CI, 0.626–1.000). In conclusion, the present results suggest that 99mTc-3P4-RGD2 SPECT is more accurate than CT in the detection of malignant SPN, and visual analysis appears to be sufficient for the characterization of SPN. PMID:27698821

  15. Comparison of the accuracy of 99mTc-3P4-RGD2 SPECT and CT in diagnosing solitary pulmonary nodules

    PubMed Central

    Zhang, Haishan; Gao, Shi; Chen, Bin; Cheng, Guanghui

    2016-01-01

    The aim of the present study was to compare technetium-99m-(polyethylene glycol-4)3-(Arg-Gly-Asp)2 (99mTc-3P4-RGD2) single-photon emission computed tomography (SPECT) and computed tomography (CT) in the noninvasive differentiation of solitary pulmonary nodules (SPNs). The present study prospectively investigated a consecutive series of 24 patients with SPN, who were newly diagnosed using radiography between September 2012 and January 2014. All patients underwent 99mTc-3P4-RGD2 SPECT and CT scans using a dual-head variable-angle γ-camera equipped with high-resolution collimators. A blinded panel of two thoracic radiologists for CT and three nuclear physicians for SPECT analyzed the images using a 5-grade scale. The SPECT images were also semi-quantitatively evaluated using tumor to non-tumor localization ratios (T/NT). The results were verified by pathological examination of the biopsy material obtained from each patient with SPN, and receiver operating characteristic (ROC) curves were generated from these results. The present results revealed that there were 17 malignant and 7 benign SPNs among the 24 patients with SPN. The mean size of the SPN was 2.1±0.6 cm. Sensitivity of visual analysis for SPECT and CT were 100.0 and 82.4%, respectively, and specificity was 71.4% for the two methods. When the T/NT SPECT semiquantitative analysis (ratio, 1.64) was used as a cut-off, the sensitivity and specificity of SPECT were 100.0 and 71.4%, respectively. The areas under the ROC curves were 0.840 for visual analysis of SPECT [95% confidence interval (CI), 0.600–1.000], 0.849 for semiquantitative analysis of SPECT (95% CI, 0.618–1.000) and 0.815 for CT (95% CI, 0.626–1.000). In conclusion, the present results suggest that 99mTc-3P4-RGD2 SPECT is more accurate than CT in the detection of malignant SPN, and visual analysis appears to be sufficient for the characterization of SPN.

  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. 30 CFR 285.301 - What do ROW grants and RUE grants include?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false What do ROW grants and RUE grants include? 285... Row Grants and Rue Grants § 285.301 What do ROW grants and RUE grants include? (a) An ROW grant: (1... pumping station or other accessory facility. (b) An RUE grant includes the site on which a facility...

  18. 30 CFR 285.301 - What do ROW grants and RUE grants include?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What do ROW grants and RUE grants include? 285... and Rights-of-Use and Easement Grants for Renewable Energy Activities Row Grants and Rue Grants § 285.301 What do ROW grants and RUE grants include? (a) An ROW grant: (1) Includes the full length of...

  19. 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

  20. 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

  1. Comparison of SPECT imaging using monoclonal antibodies with computed tomography (CT) and ultrasonography (US) for detection of recurrences of colorectal carcinoma: A prospective clinical study

    SciTech Connect

    Chatal, J.F.; Saccavini, J.C.; Douillard, J.Y.; Curtet, C.; Kremer, M.; Le Mevel, B.

    1985-05-01

    A prospective clinical study compared SPECT imaging, ultrasonography (US), and computed tomography (CT) in 22 patients clinically or biologically (increased CEA and/or CA 19-9 serum concentration) suspected of recurrence of colorectal carcinoma. The recordings were performed 3 to 5 days after injection of 111 to 129.5 MBq of cocktail of I-131-labeled anti-CEA and 19-9 (F(ab')2 fragments) monoclonal antibodies. Twenty nine tumor sites were demonstrated by surgery or concordant results of conventional diagnostic methods. SPECT visualized 21 of these 29 tumor sites (72%). It was negative in 4 cases with no demonstrated recurrence (by any method and follow-up). With respect to localization of tumor sites, SPECT visualized 7/12 liver metastases, 8/8 local pelvic recurrences and 6/8 abdominal recurrences. CT and US, systematically performed blind after SPECT, respectively visualized 9/10 and 9/12 liver metastases, 7/12 and 4/13 pelvic and abdominal recurrences. Image interpretation of SPECT was difficult due to poor tumor contrast and the large number of low-intensity, nonspecific radioactive foci. A focus had to recur in at least 3 successive slices to be considered pathological. Four tumor sites were visualized with SPECT and not with US and CT (negative or uncertain results). SPECT would appear to be useful for localizing pelvic or abdominal recurrences in cases in which interpretation of US and CT images is difficult, often because their nonspecific approach does not make it possible to differentiate a tumor recurrence from post-operative anatomical changes.

  2. 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.

  3. 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

  4. Summary of Meta-Analyses Dealing with Single-Row versus Double-Row Repair Techniques for Rotator Cuff Tears

    PubMed Central

    Spiegl, U.J.; Euler, S.A.; Millett, P.J.; Hepp, P.

    2016-01-01

    Background: Several meta-analyses of randomized clinical trials have been performed to analyze whether double-row (DR) rotator cuff repair (RCR) provides superior clinical outcomes and structural healing compared to single-row (SR) repair. The purpose of this study was to sum up the results of meta-analysis comparing SR and DR repair with respect on clinical outcomes and re-tear rates. Methods: A literature search was undertaken to identify all meta-analyses dealing with randomized controlled trials comparing clinical und structural outcomes after SR versus DR RCR. Results: Eight meta-analyses met the eligibility criteria: two including Level I studies only, five including both Level I and Level II studies, and one including additional Level III studies. Four meta-analyses found no differences between SR and DR RCR for patient outcomes, whereas four favored DR RCR for tears greater than 3 cm. Two meta-analyses found no structural healing differences between SR and DR RCR, whereas six found DR repair to be superior for tears greater than 3 cm tears. Conclusion: No clinical differences are seen between single-row and double-row repair for small and medium rotator cuff tears after a short-term follow-up period with a higher re-tear rate following single-row repairs. There seems to be a trend to superior results with double-row repair in large to massive tear sizes. PMID:27708735

  5. Abdominal and Pelvic CT

    MedlinePlus

    ... Professions Site Index A-Z Computed Tomography (CT) - Abdomen and Pelvis Computed tomography (CT) of the abdomen ... and Pelvis? What is CT Scanning of the Abdomen/Pelvis? Computed tomography, more commonly known as a ...

  6. Abdominal CT scan

    MedlinePlus

    Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... 2016:chap 133. Radiologyinfo.org. Computed tomography (CT) - abdomen and pelvis. Updated June 16, 2016. www.radiologyinfo. ...

  7. COMPARISON OF LUNG ATTENUATION AND HETEROGENEITY BETWEEN CATS WITH EXPERIMENTALLY INDUCED ALLERGIC ASTHMA, NATURALLY OCCURRING ASTHMA AND NORMAL CATS.

    PubMed

    Masseau, Isabelle; Banuelos, Alina; Dodam, John; Cohn, Leah A; Reinero, Carol

    2015-01-01

    Airway remodeling is a prominent feature of feline allergic asthma but requires biopsy for characterization. Computed tomography (CT) has appeal as a minimally invasive diagnostic test. The purpose of this prospective case-control study was to compare indices of airway remodeling between cats with experimentally induced, spontaneous asthma and healthy unaffected cats using CT. We hypothesized that experimental and spontaneous feline asthma would have similar CT airway remodeling characteristics and that these would be significantly different in healthy cats. Experimentally induced asthmatic research cats (n = 5), spontaneously asthmatic pet cats (n = 6), and healthy research cats (n = 5) were scanned unrestrained using a 64-detector row CT scanner. Inspiratory breath-hold CT scans were also performed in experimentally induced asthmatic and healthy cats. Mean ± extent variation of lung attenuation for each cat was determined using an airway inspector software program and CT images were scored for lung heterogeneity by a board-certified veterinary radiologist who was unaware of cat group status. Groups were compared using one-way ANOVA (unrestrained scans) and the Student's t-test (anesthetized scans) with significance defined as P < 0.10. Experimentally asthmatic and spontaneously asthmatic cats had significantly (P = 0.028 and P = 0.073, respectively) increased lung attenuation compared to healthy cats. Heterogeneity scores were higher in experimentally induced asthmatic cat than in healthy cats. Objective quantification of lung heterogeneity and lung volume did not differ among the three groups (P = 0.311, P = 0.181, respectively). Findings supported our hypothesis. Inspiratory breath-hold anesthetized CT scans facilitated discrimination between asthmatic and healthy cats in comparison to unrestrained CT scans.

  8. Multislice helical CT: image temporal resolution.

    PubMed

    Hui, H; Pan, T; Shen, Y

    2000-05-01

    A multislice helical computed tomography (CT) halfscan (HS) reconstruction algorithm is proposed for cardiac applications. The imaging performances (in terms of the temporal resolution, z-axis resolution, image noise, and image artifacts) of the HS algorithm are compared to the existing algorithms using theoretical models and clinical data. A theoretical model of the temporal resolution performance (in terms of the temporal sensitivity profile) is established for helical CT, in general, i.e., for any number of detector rows and any reconstruction algorithm used. It is concluded that the HS reconstruction results in improved image temporal resolution than the corresponding 180 degrees LI (linear interpolation) reconstruction and is more immune to the inconsistent data problem induced by cardiac motions. The temporal resolution of multislice helical CT with the HS algorithm is comparable to that of single-slice helical CT with the HS algorithm. In practice, the 180 degrees LI and HS-LI algorithms can be used in parallel to generate two image sets from the same scan acquisition, one (180 degrees LI) for improved z-resolution and noises, and the other (HS-LI) for improved image temporal resolution.

  9. Comparison of 128-Slice Low-Dose Prospective ECG-Gated CT Scanning and Trans-Thoracic Echocardiography for the Diagnosis of Complex Congenital Heart Disease

    PubMed Central

    Bu, Guilin; Miao, Ying; Bin, Jingwen; Deng, Sheng; Liu, Taowen; Jiang, Hongchun; Chen, Weiping

    2016-01-01

    Objective To compare prospective ECG-gated multi-slice computed tomography (MSCT) and trans-thoracic echocardiography (TTE) in the diagnosis of complex congenital heart disease (CHD). Methods This was a prospective study of consecutive patients with complex CHD (age <7 years) treated at a tertiary hospital between May 2013 and May 2015. All patients were imaged with TTE and prospective ECG-gated 128-slice spiral CT in the week before surgery. Effective radiation dose (ED) was calculated from volume CT dose index (CTDIvol) and dose length product (DLP). Image quality (5-point scale) was assessed independently by two radiologists. Using surgical findings as the reference, the diagnostic capabilities of MSCT and TTE were compared. Results Thirty-five patients (19 males) aged 1.59±1.58 years (range, 3 days to 74 months) were included. CTDIvol, DLP and ED were 0.90±0.24 mGy, 12.9±4.7 mGy∙cm and 0.64±0.21 mSv (range, 0.358–1.196 mSv), respectively. Image quality score was 4.3±0.5, and all images met the diagnostic requirements. The sensitivity, specificity, positive predictive value, and negative predictive value for diagnosing CHD were 97.2%, 99.8%, 99.0%, and 99.5%, respectively, for MSCT, and 90.6%, 99.8%, 99.0%, and 98.4%, respectively, for TTE. MSCT not only had a higher sensitivity than TTE overall (97.2% vs. 90.6%; P<0.05), but was much more sensitive for the diagnosis of extracardiac vascular abnormalities (92.0% vs. 68.0%; P<0.05). Conclusion 128-slice low-dose prospective ECG-gated CT scanning has important clinical value in the diagnosis of complex CHD in children, complementing and extending the findings of TTE. PMID:27788237

  10. 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.

  11. Comparison of Planned Versus Actual Dose Delivered for External Beam Accelerated Partial Breast Irradiation Using Cone-Beam CT and Deformable Registration

    SciTech Connect

    Hasan, Yasmin; Kim, Leonard; Wloch, Jennifer; Chi, Y.; Liang, J.; Martinez, Alvaro; Yan Di; Vicini, Frank

    2011-08-01

    Purpose: To assess the adequacy of dose delivery to the clinical target volume (CTV) using external beam (EB) accelerated partial breast irradiation (APBI). Methods and Materials: Sixteen patients treated with EB APBI underwent cone beam CT (CBCT) before each fraction and daily helical CT (HCT) scans to determine setup errors and calculate the dose per fraction. For 12 patients, an in-house image-intensity-based deformable registration program was used to register the HCTs to the planning CT and generate the cumulative dose. Treatment was 38.5 Gy in 10 fractions. EB APBI constraints from the National Surgical Adjuvant Breast and Bowel Project B39/Radiation Therapy Oncology Group 0413 Phase III protocol were used. Results: The mean setup error per CBCT registration was 9 {+-} 5 mm. Dose-volume histogram analysis showed only one patient (8%) with a decrease in the CTV V90 (8% underdosage). All other patients demonstrated adequate target coverage. PTV{sub E}VAL V90 was on average 3% (range, 0%-16%) less than planned. For the ipsilateral breast, four patients had an increase in V50 ({<=}1% increase) and three patients had an increase in V100 ({<=}9% increase). Only one patient showed an increase >5%. Four patients had an increase in ipsilateral lung V30 (maximum 3%), and one had an increase in heart V5 (1%). Four patients had an increase in MaxDose (maximum 89 cGy). Conclusions: The current CTV-to-PTV margin of 10 mm appears sufficient for {approx}92% of patients treated with EB APBI. Although expansion of the population PTV margin to 14 mm would provide {approx}97% confidence level for CTV coverage, online image guidance should be considered.

  12. 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.

  13. 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

  14. 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.

  15. Comparison of standardized uptake values measured on F-NaF PET/CT scans using three different tube current intensities

    PubMed Central

    Valadares, Agnes Araujo; Duarte, Paulo Schiavom; Woellner, Eduardo Bechtloff; Coura-Filho, George Barberio; Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto

    2015-01-01

    Objective To analyze standardized uptake values (SUVs) using three different tube current intensities for attenuation correction on 18FNaF PET/CT scans. Materials and Methods A total of 254 18F-NaF PET/CT studies were analyzed using 10, 20 and 30 mAs. The SUVs were calculated in volumes of interest (VOIs) drawn on three skeletal regions, namely, right proximal humeral diaphysis (RH), right proximal femoral diaphysis (RF), and first lumbar vertebra (LV1) in a total of 712 VOIs. The analyses covered 675 regions classified as normal (236 RH, 232 RF, and 207 LV1). Results Mean SUV for each skeletal region was 3.8, 5.4 and 14.4 for RH, RF, and LV1, respectively. As the studies were grouped according to mAs value, the mean SUV values were 3.8, 3.9 and 3.7 for 10, 20 and 30 mAs, respectively, in the RH region; 5.4, 5.5 and 5.4 for 10, 20 and 30 mAs, respectively, in the RF region; 13.8, 14.9 and 14.5 for 10, 20 and 30 mAs, respectively, in the LV1 region. Conclusion The three tube current values yielded similar results for SUV calculation. PMID:25798003

  16. Hemodynamic Changes Caused by Flow Diverters in Rabbit Aneurysm Models: Comparison of Virtual and Realistic FD Deployments Based on Micro-CT Reconstruction.

    PubMed

    Xu, Jinyu; Deng, Benqiang; 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.

  17. Comparison between coronary plaque 64-slice spiral CT characteristics and risk factors of coronary artery disease patients in Chinese Han population and Mongolian

    PubMed Central

    Bai, Zhigang; Yang, Xiaoguang; Han, Xiaodong; Dong, Peide; Liu, Aishi

    2013-01-01

    Objective : To compare the coronary atherosclerotic plaque 64-slice spiral CT characteristics and the risk factors of Han (in Inner Mongolia) and Mongolian coronary artery disease patients. Metho d s: The plaques of 126 Mongolian and 269 Han patients were analyzed by 64-slice spiral CT coronary angiography. Their gender, age, height, body mass, the history of hypertension, diabetes, smoking and family diseases, the levels of triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were compared. Results: The incidence of plaques (P <0.05), the proportion of plaques in the circumflex branch (P <0.05), the proportion of medium-severe lumen stenosis induced by plaques (P <0.05), and the proportion of obstructive plaque involved multi-branch (P <0.05) of the Mongolian patients were higher. The plaque compositions of the two groups did not differ significantly (P> 0.05). The body mass index of the Mongolian patients was higher (P <0.05). The hypertension, diabetes, smoking history, TG, TC, HDL-C and LDL-C of the two groups did not differ significantly (P> 0.05). Conclusion: The higher incidence of coronary atherosclerotic plaques and the more severe lesions of the Mongolian patients may be related to their higher body mass index. PMID:24353662

  18. Comparison between beam-stop and beam-hole array scatter correction techniques for industrial X-ray cone-beam CT

    NASA Astrophysics Data System (ADS)

    Schörner, K.; Goldammer, M.; Stephan, J.

    2011-02-01

    In industrial X-ray cone-beam computed tomography, the inspection of large-scale samples is important because of increasing demands on their quality and long-term mechanical resilience. Large-scale samples, for example made of aluminum or iron, are strongly scattering X-rays. Scattered radiation leads to artifacts such as cupping, streaks, and a reduction in contrast in the reconstructed CT-volume. We propose a scatter correction method based on sampling primary signals by employing a beam-hole array (BHA). In this indirect method, a scatter estimate is calculated by subtraction of the sampled primary signal from the total signal, the latter taken from an image where the BHA is absent. This technique is considered complementary to the better known beam-stop array (BSA) method. The two scatter estimation methods are compared here with respect to geometric effects, scatter-to-total ratio and practicability. Scatter estimation with the BHA method yields more accurate scatter estimates in off-centered regions, and a lower scatter-to-total ratio in critical image regions where the primary signal is very low. Scatter correction with the proposed BHA method is then applied to a ceramic specimen from power generation technologies. In the reconstructed CT volume, cupping almost completely vanishes and contrast is enhanced significantly.

  19. 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.

  20. 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

  1. 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 ...

  2. 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

  3. 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.

  4. 18F-FDG-PET/CT in the assessment of pulmonary solitary nodules: comparison of different analysis methods and risk variables in the prediction of malignancy

    PubMed Central

    García Vicente, Ana María; Honguero Martínez, Antonio Francisco; Jiménez Londoño, Germán Andrés; Vega Caicedo, Carlos Hugo; León Atance, Pablo; Soriano Castrejón, Ángel María

    2015-01-01

    Objective To compare the diagnostic performance of different metabolical, morphological and clinical criteria for correct presurgical classification of the solitary pulmonary nodule (SPN). Methods Fifty-five patients, with SPN were retrospectively analyzed. All patients underwent preoperative 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT). Maximum diameter in CT, maximum standard uptake value (SUVmax), histopathologic result, age, smoking history and gender were obtained. Different criteria were established to classify a SPN as malignant: (I) visually detectable metabolism, (II) SUVmax >2.5 regardless of SPN diameter, (III) SUVmax threshold depending of SPN diameter, and (IV) ratio SUVmax/diameter greater than 1. For each criterion, statistical diagnostic parameters were obtained. Receiver operating characteristic (ROC) analysis was performed to select the best diagnostic SUVmax and SUVmax/diameter cutoff. Additionally, a predictive model of malignancy of the SPN was derived by multivariate logistic regression. Results Fifteen SPN (27.3%) were benign and 40 (72.7%) malignant. The mean values ± standard deviation (SD) of SPN diameter and SUVmax were 1.93±0.57 cm and 3.93±2.67 respectively. Sensitivity (Se) and specificity (Sp) of the different diagnostic criteria were (I): 97.5% and 13.1%; (II) 67.5% and 53.3%; (III) 70% and 53.3%; and (IV) 85% and 33.3%, respectively. The SUVmax cut-off value with the best diagnostic performance was 1.95 (Se: 80%; Sp: 53.3%). The predictive model had a Se of 87.5% and Sp of 46.7%. The SUVmax was independent variables to predict malignancy. Conclusions The assessment by semiquantitative methods did not improve the Se of visual analysis. The limited Sp was independent on the method used. However, the predictive model combining SUVmax and age was the best diagnostic approach. PMID:26207210

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Strip tillage for single and twin-row peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil degradation and rising production costs have prompted grower interest in conservation tillage with high residue cover crops for peanut (Arachis hypogaea L.). The objective was to evaluate single and twin-row peanut production across three different strip tillage implements with and without a c...

  10. Interior view to the east, note the row of transmitters ...

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

    Interior view to the east, note the row of transmitters and the cables in the foreground - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Six Transmitter Building, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  11. 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)

  12. 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)

  13. 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…

  14. Peavey Duluth Annex, thirty silos. Back three R rows originally ...

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

    Peavey Duluth Annex, thirty silos. Back three R rows originally built in 1900, front three built in 1901 - Peavey Duluth Terminal Elevator, 1901 Annex, South side of first slip, north from outer end of Rice's Point, east of Garfield Avenue, Duluth, St. Louis County, MN

  15. 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

  16. 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

  17. 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

  18. Comparison on Response and Dissolution Rates Between Ursodeoxycholic Acid Alone or in Combination With Chenodeoxycholic Acid for Gallstone Dissolution According to Stone Density on CT Scan

    PubMed Central

    Lee, Jae Min; Hyun, Jong Jin; Choi, In Young; Yeom, Suk Keu; Kim, Seung Young; Jung, Sung Woo; Jung, Young Kul; Koo, Ja Seol; Yim, Hyung Joon; Lee, Hong Sik; Lee, Sang Woo; Kim, Chang Duck

    2015-01-01

    Abstract Medical dissolution of gallstone is usually performed on radiolucent gallstones in a functioning gallbladder. However, absence of visible gallstone on plain abdominal x-ray does not always preclude calcification. This study aims to compare the response and dissolution rates between ursodeoxycholic acid (UDCA) alone or in combination with chenodeoxycholic acid (CDCA) according to stone density on computed tomography (CT) scan. A total of 126 patients underwent dissolution therapy with either UDCA alone or combination of CDCA and UDCA (CNU) from December 2010 to March 2014 at Korea University Ansan Hospital. In the end, 81 patients (CNU group = 44, UDCA group = 37) completed dissolution therapy for 6 months. Dissolution rate (percentage reduction in the gallstone volume) and response to therapy (complete dissolution or partial dissolution defined as reduction in stone volume of >50%) were compared between the 2 groups. Dissolution and response rates of sludge was also compared between the 2 groups. The overall response rate was 50.6% (CNU group 43.2% vs UDCA group 59.5%, P = 0.14), and the overall dissolution rate was 48.34% (CNU group 41.5% vs UDCA group 56.5%, P = 0.13). When analyzed according to stone density, response rate was 33.3%, 87.1%, 30.0%, and 6.2% for hypodense, isodense, hyperdense, and calcified stones, respectively. Response rate (85.7% vs 88.2%, P = 0.83) and dissolution rate (81.01% vs 85.38%, P = 0.17) of isodense stones were similar between CNU and UDCA group. When only sludge was considered, the overall response rate was 87.5% (CNU group 71.4% vs UDCA group 94.1%, P = 0.19), and the overall dissolution rate was 85.42% (CNU group 67.9% vs UDCA group 92.7%, P = 0.23). Patients with isodense gallstones and sludge showed much better response to dissolution therapy with CNU and UDCA showing comparable efficacy. Therefore, CT scan should be performed before medication therapy if stone dissolution is intended

  19. 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

  20. 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

  1. 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.

  2. A mathematical model of the oar blade - water interaction in rowing.

    PubMed

    Caplan, Nicholas; Gardner, Trevor

    2007-07-01

    Our aim was to present a mathematical model of rowing and sculling that allowed for a comparison of oar blade designs. The relative movement between the oar blades and water during the drive phase of the stroke was modelled, and the lift and drag forces generated by this complex interaction were determined. The model was driven by the oar shaft angular velocity about the oarlock in the horizontal plane, and was shown to be valid against measured on-water mean steady-state shell velocity for both a heavyweight men's eight and a lightweight men's single scull. Measured lift and drag force coefficients previously presented by the authors were used as inputs to the model, whichs allowed for the influence of oar blade design on rowing performance to be determined. The commonly used Big Blade, which is curved, and it's flat equivalent were compared, and blade curvature was shown to generate a 1.14% improvement in mean boat velocity, or a 17.1-m lead over 1500 m. With races being won and lost by much smaller margins than this, blade curvature would appear to play a significant role in propulsion.

  3. Functional Outcomes After Double-Row Versus Single-Row Rotator Cuff Repair

    PubMed Central

    Nicholas, Stephen J.; Lee, Steven J.; Mullaney, Michael J.; Tyler, Timothy F.; Fukunaga, Takumi; Johnson, Christopher D.; McHugh, Malachy P.

    2016-01-01

    Background: The functional benefits of double-row (DR) versus single-row (SR) rotator cuff repair are not clearly established. Purpose: To examine the effect of DR versus SR rotator cuff repair on functional outcomes and strength recovery in patients with full-thickness tears. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Forty-nine patients were randomized to DR or SR repairs; 36 patients (13 women, 23 men; mean age, 62 ± 7 years; 20 SR, 16 DR) were assessed at a mean 2.2 ± 1.6 years after surgery (range, 1-7 years; tear size: 17 medium, 13 large, 9 massive). The following data were recorded prior to surgery and at follow-up: Penn shoulder score, American Shoulder and Elbow Surgeons (ASES), and Simple Shoulder Test (SST) results; range of motion (ROM) for shoulder flexion, external rotation (ER) at 0° and 90° of abduction, and internal rotation (IR) at 90° of abduction; and shoulder strength (Lafayette manual muscle tester) in empty- and full-can tests, abduction, and ER at 0° of abduction. Treatment (SR vs DR) × time (pre- vs postoperative) mixed-model analysis of variance was used to assess the effect of rotator cuff repair. Results: Rotator cuff repair markedly improved Penn, ASES, and SST scores (P < .001), with similar improvement between SR and DR repairs (treatment × time, P = .38-.10) and excellent scores at follow-up (DR vs SR: Penn, 91 ± 11 vs 92 ± 11 [P = .73]; ASES, 87 ± 12 vs 92 ± 12 [P = .21]; SST, 11.4 ± 1.0 vs 11.3 ± 1.0 [P = .76]). Patients with DR repairs lost ER ROM at 0° of abduction (preoperative to final follow-up, 7° ± 10° loss [P = .013]). ER ROM did not significantly change with SR repair (5° ± 14° gain, P = .16; treatment by time, P = .008). This effect was not apparent for ER ROM at 90° of abduction (treatment × time, P = .26). IR ROM improved from preoperative to final follow-up (P < .01; SR, 17° ± 27°; DR, 7° ± 21°; treatment × time, P = .23). Rotator cuff repair markedly

  4. 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

  5. 30 CFR 285.305 - How do I request an ROW grant or RUE grant?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false How do I request an ROW grant or RUE grant? 285... Obtaining Row Grants and Rue Grants § 285.305 How do I request an ROW grant or RUE grant? You must submit to MMS one paper copy and one electronic copy of a request for a new or modified ROW grant or RUE...

  6. 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...

  7. 30 CFR 285.316 - What payments are required for ROW grants or RUE grants?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... RUE grants? 285.316 Section 285.316 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION... Renewable Energy Activities Financial Requirements for Row Grants and Rue Grants § 285.316 What payments are required for ROW grants or RUE grants? Before we issue the ROW grant or RUE grant, you must pay: (a)...

  8. 30 CFR 285.305 - How do I request an ROW grant or RUE grant?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false How do I request an ROW grant or RUE grant? 285... and Rights-of-Use and Easement Grants for Renewable Energy Activities Obtaining Row Grants and Rue Grants § 285.305 How do I request an ROW grant or RUE grant? You must submit to MMS one paper copy...

  9. 30 CFR 285.309 - When will MMS issue a noncompetitive ROW grant or RUE grant?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When will MMS issue a noncompetitive ROW grant or RUE grant? 285.309 Section 285.309 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF... Obtaining Row Grants and Rue Grants § 285.309 When will MMS issue a noncompetitive ROW grant or RUE...

  10. 30 CFR 285.316 - What payments are required for ROW grants or RUE grants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... RUE grants? 285.316 Section 285.316 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE... Requirements for Row Grants and Rue Grants § 285.316 What payments are required for ROW grants or RUE grants? Before we issue the ROW grant or RUE grant, you must pay: (a) Any balance on accepted high bids to...

  11. 30 CFR 585.316 - What payments are required for ROW grants or RUE grants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... RUE grants? 585.316 Section 585.316 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF... Financial Requirements for Row Grants and Rue Grants § 585.316 What payments are required for ROW grants or RUE grants? Before we issue the ROW grant or RUE grant, you must pay: (a) Any balance on accepted...

  12. 30 CFR 585.316 - What payments are required for ROW grants or RUE grants?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... RUE grants? 585.316 Section 585.316 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF... Financial Requirements for Row Grants and Rue Grants § 585.316 What payments are required for ROW grants or RUE grants? Before we issue the ROW grant or RUE grant, you must pay: (a) Any balance on accepted...

  13. 30 CFR 585.309 - When will BOEM issue a noncompetitive ROW grant or RUE grant?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false When will BOEM issue a noncompetitive ROW grant or RUE grant? 585.309 Section 585.309 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT... Obtaining Row Grants and Rue Grants § 585.309 When will BOEM issue a noncompetitive ROW grant or RUE...

  14. 30 CFR 585.301 - What do ROW grants and RUE grants include?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false What do ROW grants and RUE grants include? 585... Rue Grants § 585.301 What do ROW grants and RUE grants include? (a) An ROW grant: (1) Includes the... station or other accessory facility. (b) An RUE grant includes the site on which a facility or...

  15. 30 CFR 585.301 - What do ROW grants and RUE grants include?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false What do ROW grants and RUE grants include? 585... Rue Grants § 585.301 What do ROW grants and RUE grants include? (a) An ROW grant: (1) Includes the... station or other accessory facility. (b) An RUE grant includes the site on which a facility or...

  16. 30 CFR 585.309 - When will BOEM issue a noncompetitive ROW grant or RUE grant?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false When will BOEM issue a noncompetitive ROW grant or RUE grant? 585.309 Section 585.309 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT... Obtaining Row Grants and Rue Grants § 585.309 When will BOEM issue a noncompetitive ROW grant or RUE...

  17. 30 CFR 585.301 - What do ROW grants and RUE grants include?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false What do ROW grants and RUE grants include? 585... Rue Grants § 585.301 What do ROW grants and RUE grants include? (a) An ROW grant: (1) Includes the... station or other accessory facility. (b) An RUE grant includes the site on which a facility or...

  18. 30 CFR 585.309 - When will BOEM issue a noncompetitive ROW grant or RUE grant?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false When will BOEM issue a noncompetitive ROW grant or RUE grant? 585.309 Section 585.309 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT... Obtaining Row Grants and Rue Grants § 585.309 When will BOEM issue a noncompetitive ROW grant or RUE...

  19. 30 CFR 585.316 - What payments are required for ROW grants or RUE grants?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... RUE grants? 585.316 Section 585.316 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF... Financial Requirements for Row Grants and Rue Grants § 585.316 What payments are required for ROW grants or RUE grants? Before we issue the ROW grant or RUE grant, you must pay: (a) Any balance on accepted...

  20. NETL CT Imaging Facility

    ScienceCinema

    None

    2016-07-12

    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. 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.

  2. 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.

  3. 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

  4. 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

  5. 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

  6. [ECG-gated bypass CT angiography--application in imaging arterial bypasses].

    PubMed

    Wintersperger, B J; Bastarrika, G; Nikolaou, K; Rist, C; Huber, A; Knez, A; Reiser, M F; Becker, C R; Vicol, C

    2004-02-01

    Nowadays coronary artery bypass grafting is increasingly performed using arterial grafts. Purpose of the study was the evaluation of a appropriate 16 detector-row CT angiography protocol in patients after predominantly arterial bypass grafting. Fourteen patients after bypass grafting were including into the study and CT angiography carried out in the early postoperative period using a 16 detector-row CT system. To reduce cardiac pulsation artifacts data acquisition was implemented using ECG-gating algorithms. Overall 43 grafts (37 arterial, 6 venous) were examined. In 13 patients surgery had been performed using composite grafts with T or TY configuration. The mean heart rate was 74.1 bpm and showed a negative correlation to the image quality (r=-0.65; p=0.01). However, all data sets were diagnostic. Contrast injection protocol allowed for a homogeneous opacification throughout the vessels of interest. All non-delineationable grafts (5) showed a close proximity to the heart (T or Y grafts). Cardiac surgery is increasingly focusing on arterial revascularisation in bypass grafting and therefore leading to new demands for non-invasive bypass graft imaging. 16 detector-row CT allows a reliable visualization of even composite arterial grafts. However, for detection of grafts in the proximity of the heart a reduction of the heart rate (<65-70) still seems to be necessary. PMID:14991132

  7. 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.

  8. 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.

  9. 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.

  10. Missing-Row Contractive Reconstruction on Au(311)

    NASA Astrophysics Data System (ADS)

    Ercolessi, Furio; Tosatti, Erio

    All the low-index surfaces of gold are known to reconstruct, and their vicinals often exhibit magic orientations. The (311) orientation lies in between (100) and (111), and can be regarded as either a (111) or (100) vicinal with a very high step density, or as a flat open surface. In view of rather puzzling reconstructions observed experimentally [(1 × 4), (1 × 5), (1 × 6)], we have undertaken a structural study of Au(311) using the glue model and molecular-dynamics-based simulated annealing. The optical geometry is a (1 × 5) missing-row structure with (111) and reconstructed (100) microfacets, and an alternation of (1 × 2) and (1 × 3) hills. An extra atomic row is present on (1 × 3) hills to optimize packing. The experimentally observed disappearance of the reconstruction between 700 and 750 K is probably associated with an order-disorder transition similar to that of Au(110).

  11. A parallel householder tridiagonalization stratagem using scattered row decomposition

    NASA Technical Reports Server (NTRS)

    Chang, H. Y.; Utku, S.; Salama, M.; Rapp, D.

    1988-01-01

    Householder's method for tridiagonalizing a real symmetric matrix, a major step in evaluating eigenvalues of the matrix, is modified into a parallel algorithm for a concurrent machine of message passing type. Each processor of the concurrent machine has its own CPU, communications control and local memory. Messages are passed through connections between processors. Although the basic algorithm is inherently serial, the computations can be spread over all processors by scattering different rows of the matrix into processors, hence the term 'Scattered Row Decomposition'. The steps in the serial and the parallel algorithms are identified. Expressions for efficiency and speedup are given in terms of problem and machine parameters. For a concurrent machine of ring type interconnection, a selected representative problem of large order exhibits efficiency approaching 66 per cent.

  12. In vitro description of a new technique for stapled side-to-side jejunocecal anastomosis in horses and CT scan anatomical comparison with other techniques

    PubMed Central

    2014-01-01

    Background Stapled jejunocecal anastomoses are commonly performed in equine abdominal surgery. They carry higher complication rates compared to handsewn techniques. In human surgery various causes likely to lead to failure of stapled techniques have been evaluated, including staple line failure. Recently Freeman proposed a technique to perform a stapled jejunocecal anastomosis in horses while avoiding blind pouch formation. The aim of this study is to describe a method for stapled side-to-side jejunocecal anastomosis in horses and to compare it with other techniques with computed tomography to assess stomal area, shape and blind pouch size. Methods Intestinal specimens comprising the cecum, ileum and jejunum from 18 horses were collected and were divided into three groups. In Group S a standard stapled side-to-side jejunocecal anastomosis was performed. In Group F the anastomosis was performed using a modified technique proposed by Freeman. In Group G the anastomosis was performed with a modified technique proposed by the authors. Inflated bowel segments were CT scanned to obtain a MultiPlanar Reconstruction of the stoma and afferent small intestine before calculating the cross-sectional area of each of these regions. The ratio of the measured areas was compared between the three techniques. The volume of the blind-end pouch was measured and its ratio with the intestinal area compared between techniques. The cecum was opened and the length of the stoma measured with a caliper and compared to the intended initial length. Results The stomal/intestinal area ratio was not significantly different between techniques. No statistically significant difference was found in the stomal ideal/real perimeter ratio. There was no statistically significant difference in the intended/real stomal length ratio, and all techniques featured an increase in stomal length ranging from 2 to 12 %. Blind pouch formation was a consistent finding in Group S and was virtually absent in Groups F

  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. 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

  15. 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.

  16. 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.

  17. 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.

  18. Length to diameter ratio and row number effects in short pin fin heat transfer

    NASA Technical Reports Server (NTRS)

    Brigham, B. A.; Vanfossen, G. J.

    1982-01-01

    The relative effects of pin length to diameter ratio and of pin row geometry on the heat transfer from pin fins, was determined. Array averaged heat transfer coefficients on pin and endwall surfaces were measured for two configurations of staggered arrays of short pin fins (length to diameter ratio of 4). One configuration contained eight streamwise rows of pins, while the other contained only four rows. Results showed that both the 8-row and the 4-row configurations for an L sub p/D of 4, exhibit higher heat transfer than in similar tests on shorter pin fns (L sub p/D of 1/2 and 2). It was also found that for this L sub p/D ratio, the array averaged heat transfer was slightly higher with eight rows of staggered pins than with only four rows.

  19. Length to diameter ratio and row number effects in short pin fin heat transfer

    NASA Technical Reports Server (NTRS)

    Brigham, B. A.; Vanfossen, G. J.

    1984-01-01

    The relative effects of pin length to diameter ratio and of pin row geometry on the heat transfer from pin fins, was determined. Array averaged heat transfer coefficients on pin and endwall surfaces were measured for two configurations of staggered arrays of short pin fins (length to diameter ratio of 4). One configuration contained eight streamwise rows of pins, while the other contained only four rows. Results showed that both the 8-row and the 4-row configurations for an L sub p/D of 4, exhibit higher heat transfer than in similar tests on shorter pin fins (L sub p/D of 1/2 and 2). It was also found that for this L sub p/D ratio, the array averaged heat transfer was slightly higher with eight rows of staggered pins than with only four rows. Previously announced in STAR as N83-14431

  20. Tilted cone-beam reconstruction with row-wise fan-to-parallel rebinning.

    PubMed

    Hsieh, Jiang; Tang, Xiangyang

    2006-10-21

    Reconstruction algorithms for cone-beam CT have been the focus of many studies. Several exact and approximate reconstruction algorithms were proposed for step-and-shoot and helical scanning trajectories to combat cone-beam related artefacts. In this paper, we present a new closed-form cone-beam reconstruction formula for tilted gantry data acquisition. Although several algorithms were proposed in the past to combat errors induced by the gantry tilt, none of the algorithms addresses the scenario in which the cone-beam geometry is first rebinned to a set of parallel beams prior to the filtered backprojection. We show that the image quality advantages of the rebinned parallel-beam reconstruction are significant, which makes the development of such an algorithm necessary. Because of the rebinning process, the reconstruction algorithm becomes more complex and the amount of iso-centre adjustment depends not only on the projection and tilt angles, but also on the reconstructed pixel location. In this paper, we first demonstrate the advantages of the row-wise fan-to-parallel rebinning and derive a closed-form solution for the reconstruction algorithm for the step-and-shoot and constant-pitch helical scans. The proposed algorithm requires the 'warping' of the reconstruction matrix on a view-by-view basis prior to the backprojection step. We further extend the algorithm to the variable-pitch helical scans in which the patient table travels at non-constant speeds. The algorithm was tested extensively on both the 16- and 64-slice CT scanners. The efficacy of the algorithm is clearly demonstrated by multiple experiments.

  1. Split-Bolus Multidetector-Row Computed Tomography Technique for Characterization of Focal Liver Lesions in Oncologic Patients

    PubMed Central

    Scialpi, Michele; Pierotti, Luisa; Gravante, Sabrina; Rebonato, Alberto; Piscioli, Irene; D’Andrea, Alfredo; Schiavone, Raffaele; Palumbo, Barbara

    2016-01-01

    Background In oncologic patients, the liver is the most common target for metastases. An accurate detection and characterization of focal liver lesions in patients with known primary extrahepatic malignancy are essential to define management and prognosis. Objectives To assess the diagnostic accuracy of the split-bolus multidetector-row computed tomography (MDCT) protocol in the characterization of focal liver lesions in oncologic patients. Patients and Methods We retrospectively analyzed the follow-up split-bolus 64-detector row CT protocol in 36 oncologic patients to characterize focal liver lesions. The split-bolus MDCT protocol by intravenous injection of two boluses of contrast medium combines the hepatic arterial phase (HAP) and hepatic enhancement during the portal venous phase (PVP) in a single-pass. Results The split-bolus MDCT protocol detected 208 lesions and characterized 186 (89.4%) of them: typical hemangiomas (n = 9), atypical hemangiomas (n = 3), cysts (n = 78), hypovascular (n = 93) and hypervascular (n = 3) metastases. Twenty two (10.6%) hypodense lesions were categorized as indeterminate (≤5 mm). The mean radiation dose was 24.5±6.5 millisieverts (mSv). Conclusion The designed split-bolus MDCT technique can be proposed alternatively to triphasic MDCT and in a single-pass to PVP in the initial staging and in the follow-up respectively in oncologic patients.

  2. 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

  3. 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

  4. 30 CFR 585.310 - What is the effective date of an ROW grant or RUE grant?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... RUE grant? 585.310 Section 585.310 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF... Obtaining Row Grants and Rue Grants § 585.310 What is the effective date of an ROW grant or RUE grant? Your ROW grant or RUE grant becomes effective on the date established by BOEM on the ROW grant or RUE...

  5. 30 CFR 285.303 - How long will my ROW grant or RUE grant remain in effect?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false How long will my ROW grant or RUE grant remain... Renewable Energy Activities Row Grants and Rue Grants § 285.303 How long will my ROW grant or RUE grant remain in effect? Your ROW grant or RUE grant will remain in effect for as long as the...

  6. 30 CFR 585.303 - How long will my ROW grant or RUE grant remain in effect?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false How long will my ROW grant or RUE grant remain... Row Grants and Rue Grants § 585.303 How long will my ROW grant or RUE grant remain in effect? Your ROW grant or RUE grant will remain in effect for as long as the associated activities are...

  7. 30 CFR 585.310 - What is the effective date of an ROW grant or RUE grant?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... RUE grant? 585.310 Section 585.310 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF... Obtaining Row Grants and Rue Grants § 585.310 What is the effective date of an ROW grant or RUE grant? Your ROW grant or RUE grant becomes effective on the date established by BOEM on the ROW grant or RUE...

  8. 30 CFR 585.310 - What is the effective date of an ROW grant or RUE grant?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... RUE grant? 585.310 Section 585.310 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF... Obtaining Row Grants and Rue Grants § 585.310 What is the effective date of an ROW grant or RUE grant? Your ROW grant or RUE grant becomes effective on the date established by BOEM on the ROW grant or RUE...

  9. 30 CFR 585.303 - How long will my ROW grant or RUE grant remain in effect?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false How long will my ROW grant or RUE grant remain... Row Grants and Rue Grants § 585.303 How long will my ROW grant or RUE grant remain in effect? Your ROW grant or RUE grant will remain in effect for as long as the associated activities are...

  10. 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

  11. 180 degrees rotation of ciliary rows and its morphogenetic implications in Tetrahymena pyriformis.

    PubMed

    Ng, S F; Frankel, J

    1977-03-01

    With quasi-surgical techniques, longitudinal somatic ciliary rows in Tetrahymena pyriformis have been rotated 180 degrees. New structures formed in the rotated ciliary rows during growth and reproduction are disposed 180 degrees opposite to their normal positions or orientations, confirming the earlier findings of Beisson and Sonneborn on Paramecium. However, during cell fission the rotated ciliary rows exhibit abnormality in orientation along the fission zone; the configuration of these rows near the anterior end of the posterior product of fission is consequently affected. Rotated ciliary rows have been employed as a tool in the analysis of morphogenetic problems: (a) The contractile vacuole pore is normally located on the left side of a ciliary row; but it is on the right of inverted rows. Hence, the morphogenetic properties of the two sides of the ciliary row associated with the contractile vacuole pore are different and this difference is the sole determinative factor as to the side of the ciliary row on which the contractile vacuole pore is located. (b) The process that generates the rotated ciliary rows frequently also brings about the implantation of an extra band of longitudinal microtubules at a specific site on the cell surface. This extra structure is inheritable, which opens up opportunities for the study of microtubular assembly in vivo. PMID:403524

  12. Future generation CT imaging.

    PubMed

    Walter, Deborah; De Man, Bruno; Iatrou, Maria; Edic, Peter M

    2004-02-01

    X-ray CT technology has been available for more than 30 years, yet continued technological advances have kept CT imaging at the forefront of medical imaging innovation. Consequently, the number of clinical CT applications has increased steadily. Other imaging modalities might be superior to CT imaging for some specific applications, but no other single modality is more often used in chest imaging today. Future technological developments in the area of high-resolution detectors, high-capacity x-ray tubes, advanced reconstruction algorithms, and improved visualization techniques will continue to expand the imaging capability. Future CT imaging technology will combine improved imaging capability with advanced and specific computer-assisted tools, which will expand the usefulness of CT imaging in many areas.

  13. PET/CT artifacts.

    PubMed

    Blodgett, Todd M; Mehta, Ajeet S; Mehta, Amar S; Laymon, Charles M; Carney, Jonathan; Townsend, David W

    2011-01-01

    There are several artifacts encountered in positron emission tomography/computed tomographic (PET/CT) imaging, including attenuation correction (AC) artifacts associated with using CT for AC. 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.

  14. Esophageal carcinoma: CT findings

    SciTech Connect

    Quint, L.E.; Glazer, G.M.; Orringer, M.B.; Gross, B.H.

    1985-04-01

    Preoperative CT scans of 33 patients with esophageal cancer were reviewed to assess staging accuracy and define the role of CT in patients being considered for transhiatal blunt esophagectomy. Surgical and pathological verification was obtained in all cases. Only 13 tumors were staged correctly according to the TNM classification. In addition, CT was not useful in assessing resectability because of its low accuracy in evaluating aortic invasion and the fact that few patients had tracheobronchial or aortic invasion or hepatic metastases at presentation.

  15. 30 CFR 585.303 - How long will my ROW grant or RUE grant remain in effect?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false How long will my ROW grant or RUE grant remain... Row Grants and Rue Grants § 585.303 How long will my ROW grant or RUE grant remain in effect? (a) Each ROW or RUE grant will have a preliminary term of 12 months from the date of issuance of the ROW or...

  16. CT angiography - chest

    MedlinePlus

    Computed tomography angiography - thorax; CTA - lungs; Pulmonary embolism - CTA chest; Thoracic aortic aneurysm - CTA chest; Venous thromboembolism - CTA lung; Blood clot - CTA lung; Embolus - CTA lung; CT ...

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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

  2. Assessment of Renal Function in Patients with Unilateral Ureteral Obstruction Using Whole-Organ Perfusion Imaging with 320-Detector Row Computed Tomography

    PubMed Central

    Yu, Juan; Feng, You-Zhen; Xian, Zhao-Hui; Yang, Wen-Cai; Mo, Xu-Kai

    2015-01-01

    Background Obstructed nephropathy is a common complication of several disease processes. Accurate evaluation of the functional status of the obstructed kidney is important to achieve a good outcome. The purpose of this study was to investigate renal cortical and medullary perfusion changes associated with unilateral ureteral obstruction (UUO) using whole-organ perfusion imaging with 320-detector row computed tomography (CT). Methodology/Principle Findings Sixty-four patients with UUO underwent whole-organ CT perfusion imaging. Patients were divided into 3 groups, mild, moderate, and severe, based on hydronephrosis severity. Twenty sex- and age-matched patients without renal disease, who referred to abdominal CT, were chosen as control subjects. Mean cortical and medullary perfusion parameters of obstructed and contralateral kidneys were compared, and mean perfusion ratios between obstructed and contralateral kidneys were calculated and compared. Mean cortical or medullary blood flow (BF) and blood volume (BV) of the obstructed kidneys in the moderate UUO and BF, BV, and clearance (CL) in the severe UUO were significantly lower than those of the contralateral kidneys (p < 0.05). The mean cortical or medullary BF of the obstructed kidney in the moderate UUO, and BF, BV, and CL in the severe UUO were significantly lower than those of the kidneys in control subjects (p < 0.05). Mean cortical or medullary BF of the non-obstructed kidneys in the severe UUO were statistically greater than that of normal kidneys in control subjects (p < 0.05). An inverse correlation was observed between cortical and medullary perfusion ratios and grades of hydronephosis (p < 0.01). Conclusions/Significance Perfusion measurements of the whole kidney can be obtained with 320-detector row CT, and estimated perfusion ratios have potential for quantitatively evaluating UUO renal injury grades. PMID:25874690

  3. Can Row Spacing Influence Arthropod Communities in Soybean? Implications for Early and Late Planting.

    PubMed

    Buchanan, Amanda L; Zobel, Emily; Hinds, Jermaine; Rosario-Lebron, Armando; Hooks, Cerruti R R

    2015-06-01

    Row spacing in agricultural systems can influence crop yield as well as pest and predator abundances. Soybean (Glycine max L. Merrill) growers in Maryland typically plant in narrow (∼19 cm), medium (∼38 cm), or wide (∼76 cm)-spaced rows, and there is a general lack of information on how these row-spacing schemes influence arthropod abundance and soybean yields. A study was conducted during two growing seasons to determine the effect of soybean row spacing and planting date (early and late) on soybean arthropods and yield. Despite a great deal of variation in arthropod responses to row spacing, and interactions between row spacing and study year, leaf-feeding herbivores were generally more abundant in narrow-spaced soybeans. All arthropod functional groups were more abundant, and yield was greater in early-planted soybeans relative to late-planted soybeans. Potential causes and implications of these finding are discussed.

  4. Arthroscopic Double-Row Transosseous Equivalent Rotator Cuff Repair with a Knotless Self-Reinforcing Technique

    PubMed Central

    Mook, William R.; Greenspoon, Joshua A.; Millett, Peter J.

    2016-01-01

    Background: Rotator cuff tears are a significant cause of shoulder morbidity. Surgical techniques for repair have evolved to optimize the biologic and mechanical variables critical to tendon healing. Double-row repairs have demonstrated superior biomechanical advantages to a single-row. Methods: The preferred technique for rotator cuff repair of the senior author was reviewed and described in a step by step fashion. The final construct is a knotless double row transosseous equivalent construct. Results: The described technique includes the advantages of a double-row construct while also offering self reinforcement, decreased risk of suture cut through, decreased risk of medial row overtensioning and tissue strangulation, improved vascularity, the efficiency of a knotless system, and no increased risk for subacromial impingement from the burden of suture knots. Conclusion: Arthroscopic knotless double row rotator cuff repair is a safe and effective method to repair rotator cuff tears. PMID:27733881

  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. A DNA marker closely linked to the vrs1 locus (row-type gene) indicates multiple origins of six-rowed cultivated barley ( Hordeum vulgare L.).

    PubMed

    Tanno, K; Taketa, S; Takeda, K; Komatsuda, T

    2002-01-01

    The origin of six-rowed cultivated barley was studied using a DNA marker cMWG699 closely linked to the vrs1 locus. Restriction patterns of the PCR-amplified product of the cMWG699 locus were examined in 280 cultivated ( Hordeum vulgare ssp. vulgare) and 183 wild ( H. vulgare ssp. spontaneum) barleys. Nucleotide sequences of the PCR products were also examined in selected accessions. Six-rowed cultivated barleys were divided into two distinct groups, types I and II. Type I six-rowed cultivated barley was distributed widely while type II six-rowed cultivated barley was found only in the Mediterranean region. The type I sequence was also found in a wild barley accession from Turkmenistan whereas the type II sequence was also found in a two-rowed cultivated barley from North Africa and a wild barley from Morocco. These results suggested that the six-rowed type I and II barleys were derived from two-rowed type I and II barleys, respectively, by independent mutations at the vrs1 locus.

  7. 30 CFR 585.305 - How do I request an ROW grant or RUE grant?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false How do I request an ROW grant or RUE grant? 585... Grants and Rue Grants § 585.305 How do I request an ROW grant or RUE grant? You must submit to BOEM one paper copy and one electronic copy of a request for a new or modified ROW grant or RUE grant. You...

  8. 30 CFR 585.305 - How do I request an ROW grant or RUE grant?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false How do I request an ROW grant or RUE grant? 585... Grants and Rue Grants § 585.305 How do I request an ROW grant or RUE grant? You must submit to BOEM one paper copy and one electronic copy of a request for a new or modified ROW grant or RUE grant. You...

  9. 30 CFR 585.305 - How do I request an ROW grant or RUE grant?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false How do I request an ROW grant or RUE grant? 585... Grants and Rue Grants § 585.305 How do I request an ROW grant or RUE grant? You must submit to BOEM one paper copy and one electronic copy of a request for a new or modified ROW grant or RUE grant. You...

  10. 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

  11. [CT-expo--a novel program for dose evaluation in CT].

    PubMed

    Stamm, G; Nagel, H D

    2002-12-01

    CT-Expo is a novel MS Excel application for assessing the radiation doses delivered to patients undergoing CT examinations, based on computational methods that were used to analyze the data collected in the German survey on CT practice in 1999. The program enables the calculation of all dose quantities of practical value, such as axial dose free-in-air, weighted CTDI, dose-length product, effective dose and uterine dose. In contrast to existing programs for CT dose assessment, CT-Expo offers a number of unique features, such as gender-specific dose calculation for all age groups (adults, children, newborns), applicability to all existing scanner models including correction of scanner-specific influences, and the possibility of comparison with the results from the German CT survey on CT practice. Three different application modules offer free and standardized dose calculations as well as a comprehensive benchmarking section including guidance on dose optimization. The program is available as shareware in both German and English version. Additional information and a demo version free of charge can be requested via e-mail from the author's address stamm.georg@mh-hannover. de) or from the web page http://www.mh-hannover.de/kliniken/radiologie/str_04.html.

  12. CT of Gastric Emergencies.

    PubMed

    Guniganti, Preethi; Bradenham, Courtney H; Raptis, Constantine; Menias, Christine O; Mellnick, Vincent M

    2015-01-01

    Abdominal pain, nausea, and vomiting are common presenting symptoms among adult patients seeking care in the emergency department, and, with the increased use of computed tomography (CT) to image patients with these complaints, radiologists will more frequently encounter a variety of emergent gastric pathologic conditions on CT studies. Familiarity with the CT appearance of emergent gastric conditions is important, as the clinical presentation is often nonspecific and the radiologist may be the first to recognize gastric disease as the cause of a patient's symptoms. Although endoscopy and barium fluoroscopy remain important tools for evaluating patients with suspected gastric disease in the outpatient setting, compared with CT these modalities enable less comprehensive evaluation of patients with nonspecific complaints and are less readily available in the acute setting. Endoscopy is also more invasive than CT and has greater potential risks. Although the mucosal detail of CT is relatively poor compared with barium fluoroscopy or endoscopy, CT can be used with the appropriate imaging protocols to identify inflammatory conditions of the stomach ranging from gastritis to peptic ulcer disease. In addition, CT can readily demonstrate the various complications of gastric disease, including perforation, obstruction, and hemorrhage, which may direct further clinical, endoscopic, or surgical management. We will review the normal anatomy of the stomach and discuss emergent gastric disease with a focus on the usual clinical presentation, typical imaging appearance, and differentiating features, as well as potential imaging pitfalls.

  13. 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.

  14. Women's religious conversions on death row: theorizing religion and state.

    PubMed

    Cooey, P M

    2002-01-01

    Most scholars of religion who approach the phenomena associated with religious conversion in order to theorize religion tend to ignore the legal and political implications of the actual context in which conversion occurs for theorizing religion itself. Meanwhile, political and legal theorists who attend to the implications of executing convicted murderers who undergo religious conversion on death row err in a different direction. They virtually ignore the significance of the claims made by the converts and their associates about the conversion themselves for theorizing the state. Scholars across disciplines increasingly address issues of race, class, gender, and sexual orientation in respect to theorizing religion and theorizing the state independently of one another. At the same time, they do not seize the opportunity to incorporate their analyses into a wider study of the sociocultural production of religion and state in relation to each other. I examine the religious conversion of Karla Faye Tucker and Wanda Jean Allen on death row, as well as the scholarship that their convictions, conversions, and executions have generated across academic disciplines and fields. Close examination illustrates well the necessity for theorizing religion and the state in relation to one another in order to understand either adequately.

  15. 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

  16. 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

  17. Statistical characteristics of streak artifacts on CT images: relationship between streak artifacts and mA s values.

    PubMed

    Imai, Kuniahru; Ikeda, Mitsuru; Enchi, Yukihiro; Niimi, Takanaga

    2009-02-01

    The purpose of this study is to investigate how streak artifacts on computed tomography (CT) images vary with reduction in radiation doses by assessing the quantitative relationship between the streak artifacts and milliampere-time product (mA s) values. A commercially available chest phantom was used to measure the streak artifacts on the CT images obtained using a 4- and 16-multidetector-row helical CT scanners with various mA s values at a constant tube voltage of 120 kVp. The cardiac slice image was employed as a target image for evaluating the streak artifacts on the CT image. Eighty parallel line segments with a length of 20 pixels were placed perpendicular to numerous streak artifacts on the cardiac slice image, and the largest difference between adjacent CT values in each of the 80 CT-value profiles of these line segments was employed as a feature variable of streak artifacts; these feature variables have been analyzed by the extreme value theory. The largest difference between adjacent CT values in each CT-value profile can be statistically modeled by a Gumbel distribution. Further, the maximum level of streak artifacts on CT images that will be tolerated for clinical use and low-dose CT screening examination was expected to be estimated using the location parameter in the Gumbel distribution.

  18. A detection method for streak artifacts and radiological noise in a non-uniform region in a CT image.

    PubMed

    Imai, Kuniharu; Ikeda, Mitsuru; Enchi, Yukihiro; Niimi, Takanaga

    2010-01-01

    By using the CT images obtained by subtracting two CT images acquired under the same conditions and slice locations, we have devised a method for detecting streak artifacts in non-uniform regions and only radiological noise components in CT images. A chest phantom was scanned using 16- and 64-multidetector row helical CT scanners with various mAs values at 120kVp. The upper lung slice image was employed as a target image for evaluating the streak artifacts and radiological noise. One hundred parallel line segments with a length of 80 pixels were placed on the subtracted CT image, and the largest CT value in each CT value profile was employed as a feature variable of the streak artifacts; these feature variables were analyzed with the extreme value theory (Gumbel distribution). To detect only the radiological noise, all CT values contained in the 100 line profile were plotted on normal probability paper and the standard deviation was estimated from the inclination of its fitted line for the CT value plots. The two detection methods devised in this study were able to evaluate the streak artifacts and radiological noise in the CT images with high accuracy.

  19. A method for benchmarking CT scanners.

    PubMed

    Al-Farsi, A; Michael, G; Thiele, D

    2005-09-01

    This study involved the development of an objective method to compare the performance of five CT scanners for the purpose of benchmarking. The method used to assess the scanners was to determine the dose-normalised noise at a spatial resolution of 5.5 cm(-1). This gave a dose-normalised percent noise between 0.37% and 0.76%. The scanners were also assessed for radiation dose to patients undergoing abdomen and head CT examinations. Patients' dose-length product (DLP) for the abdomen clinical examinations varied from 305 to 685 mGy-cm, and for the head clinical examinations from 333 to 900 mGy-cm. The study results demonstrated that the comparison of dose and spatial resolution normalised percent noise levels is a useful method of comparing CT scanner performance.

  20. The utility of dual bioelectrical impedance analysis in detecting intra-abdominal fat area in obese patients during weight reduction therapy in comparison with waist circumference and abdominal CT.

    PubMed

    Yamakage, Hajime; Ito, Ryo; Tochiya, Mayu; Muranaka, Kazuya; Tanaka, Masashi; Matsuo, Yoshiyuki; Odori, Shinji; Kono, Shigeo; Shimatsu, Akira; Satoh-Asahara, Noriko

    2014-01-01

    An increase in intra-abdominal fat area (IAFA) is an essential component of metabolic syndrome (MetS). Waist circumference (WC) is not a precise measure of IAFA, and computed tomography (CT) is unsuitable for frequent monitoring. Here, we examined utility of a dual bioelectrical impedance analysis (Dual BIA) for measuring IAFA in obese patients during weight reduction. Fat distribution was measured by Dual BIA and CT in 100 obese outpatients. All fat areas including total, IAFA, and subcutaneous fat by Dual BIA were more closely correlated with those by CT than WC. Estimated IAFA by Dual BIA was significantly correlated with number of MetS components as well as CT, but WC was not. Furthermore, in 61 obese patients who received 6-month weight reduction therapy, estimated IAFA by Dual BIA showed an earlier and greater decrease as well as that by CT than WC and BMI. In addition, decrease in estimated IAFA by Dual BIA through weight reduction had a higher correlation with decrease in IAFA by CT, than WC. This study is the first to demonstrate that the change in estimated IAFA by Dual BIA was highly correlated with that in IAFA by CT during weight reduction therapy. Our findings also indicate that estimated IAFA by Dual BIA is, potentially, a better indicator of severity of MetS, cardiovascular risk factors, and effectiveness of weight reduction than WC, and equal to IAFA by CT. Estimated IAFA by Dual BIA may be useful for monitoring the effectiveness of weight reduction therapy in obese patients.

  1. SNOMED CT in pathology.

    PubMed

    García-Rojo, Marcial; Daniel, Christel; Laurinavicius, Arvydas

    2012-01-01

    Pathology information systems have been using SNOMED II for many years, and in most cases, they are in a migration process to SNOMED CT. COST Action IC0604 (EURO-TELEPATH) has considered terminology normalization one of its strategic objectives. This paper reviews the use of SNOMED CT in healthcare, with a special focus in pathology. Nowadays, SNOMED CT is mainly used for concept search and coding of clinical data. Some ontological errors found in SNOMED CT are described. The Integrating the Healthcare Enterprise (IHE) initiative has fostered the use of SNOMED CT, also in Pathology, as recommended in the Supplement Anatomic Pathology Structured Reports of the IHE Anatomic Pathology Technical Framework. Rule governing concept post-coordination is also described. Some recent initiatives are trying to define a SNOMED CT subset for Pathology. The Spanish Society of Pathology has defined a subset for specimens and procedures in Pathology. Regarding diagnosis coding, the morphological abnormality sub-hierarchy of SNOMED CT need to be significantly extended and improved to become useful for pathologists. A consensus is needed to encode pathology reports with the adequate hierarchies and concepts. This will make the implementation of pathology structured reports more feasible.

  2. Metrology with μCT: precision challenge

    NASA Astrophysics Data System (ADS)

    Suppes, Alexander; Neuser, Eberhard

    2008-08-01

    Over the last years computed tomography (CT) with conventional x-ray sources has evolved from imaging method in medicine to a well established technology for industrial applications in the field of material science, microelectronics, geology, etc. By using modern microfocus and nanofocus® X-ray tubes, parts can be scanned with sub-micrometer resolutions. Currently, micro-CT is used more and more as a technology for metrological applications. Especially if complex parts with hidden or difficult accessible surfaces have to be measured, CT offers big advantages comparing with conventional tactile or optical coordinate measuring machines (CMMs): high density of measurement points and fast capturing of the complete sample's geometry. When using this modern technology the question arises how precise a CT based CMM can measure in comparison to conventional CMMs? To characterize the metrological capabilities of a tactile or optical CMM, internationally standardized characteristics like length measurement error and probing error are used. To increase the acceptance of CT as a metrological method, the definition and usage of these parameters is important. In this paper, an overview of the process chain in CT based metrology will be given and metrological characteristics will be described. With the help of a special material standard designed and calibrated by PTB-National Metrology Institute of Germany-the influence of methods for beam hardening correction and for surface extraction on the metrological characteristics will be analyzed. It will be shown that with modern micro-CT systems length measurement error of less than 1μm for an object diameter of 20 mm can be reached.

  3. 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.

  4. 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...

  5. 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…

  6. 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...

  7. 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)

  8. 30 CFR 285.309 - When will MMS issue a noncompetitive ROW grant or RUE grant?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... or RUE grant? 285.309 Section 285.309 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION... Renewable Energy Activities Obtaining Row Grants and Rue Grants § 285.309 When will MMS issue a noncompetitive ROW grant or RUE grant? If we approve or approve with conditions your GAP, we may offer you...

  9. 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...

  10. 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. (1) Regulated area. The regulated area is formed by a line drawn directly across the Savannah...

  11. 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. (1) Regulated area. The regulated area is formed by a line drawn directly across the Savannah...

  12. 33 CFR 100.724 - Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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. (1) Regulated area. The regulated area is formed by a line drawn directly across the Savannah...

  13. 33 CFR 100.724 - Annual Augusta Invitational Rowing Regatta; Savannah River, Augusta, GA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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. (1) Regulated area. The regulated area is formed by a line drawn directly across the Savannah...

  14. 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. (1) Regulated area. The regulated area is formed by a line drawn directly across the Savannah...

  15. 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

  16. 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, (...

  17. Important role of muscle carnosine in rowing performance.

    PubMed

    Baguet, Audrey; Bourgois, Jan; Vanhee, Lander; Achten, Eric; Derave, Wim

    2010-10-01

    The role of the presence of carnosine (β-alanyl-L-histidine) in millimolar concentrations in human skeletal muscle is poorly understood. Chronic oral β-alanine supplementation is shown to elevate muscle carnosine content and improve anaerobic exercise performance during some laboratory tests, mainly in the untrained. It remains to be determined whether carnosine loading can improve single competition-like events in elite athletes. The aims of the present study were to investigate if performance is related to the muscle carnosine content and if β-alanine supplementation improves performance in highly trained rowers. Eighteen Belgian elite rowers were supplemented for 7 wk with either placebo or β-alanine (5 g/day). Before and following supplementation, muscle carnosine content in soleus and gastrocnemius medialis was measured by proton magnetic resonance spectroscopy ((1)H-MRS) and the performance was evaluated in a 2,000-m ergometer test. At baseline, there was a strong positive correlation between 100-, 500-, 2,000-, and 6,000-m speed and muscle carnosine content. After β-alanine supplementation, the carnosine content increased by 45.3% in soleus and 28.2% in gastrocnemius. Following supplementation, the β-alanine group was 4.3 s faster than the placebo group, whereas before supplementation they were 0.3 s slower (P = 0.07). Muscle carnosine elevation was positively correlated to 2,000-m performance enhancement (P = 0.042 and r = 0.498). It can be concluded that the positive correlation between baseline muscle carnosine levels and rowing performance and the positive correlation between changes in muscle carnosine and performance improvement suggest that muscle carnosine is a new determinant of rowing performance. PMID:20671038

  18. 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

  19. 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

  20. Computed Tomography (CT) -- Head

    MedlinePlus

    ... further information please consult the ACR Manual on Contrast Media and its references. The risk of serious allergic ... Angiography (CTA) Stroke Brain Tumors Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, ...

  1. Computed Tomography (CT) -- Sinuses

    MedlinePlus

    ... further information please consult the ACR Manual on Contrast Media and its references. The risk of serious allergic ... X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - Sinuses About ...

  2. Pelvic CT scan

    MedlinePlus

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... creates detailed pictures of the body, including the pelvis and areas near the pelvis. The test may ...

  3. Pediatric CT Scans

    Cancer.gov

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  4. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... on film. Three-dimensional (3D) models of the leg can be created by adding the slices together. ...

  5. CT Colonography (Virtual Colonoscopy)

    MedlinePlus

    ... into the colon using a hand-held squeeze bulb. Sometimes an electronic pump is used to deliver ... When you enter the CT scanner room, special light lines may be seen projected onto your body, ...

  6. CT Angiography (CTA)

    MedlinePlus

    ... CT Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ...

  7. 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.

  8. Symbolic Givens reduction and row-ordering in large sparse least squares problems

    SciTech Connect

    Ostrouchov, G.

    1987-05-01

    In the solution of large sparse least squares problems by Givens factorization, a preliminary symbolic step that determines a good processing order and a data structure for the matrix factor is used. In this paper, it is shown that a processing order equivalent to sequential processing by rows can be as good as any processing order using a single pivot row in each column. A notion of local acceptability in row-ordering is introduced and shown to reduce fill globally. Row-orderings satisfying this notion are essentially equivalent to sequential processing by rows and the nature of intermediate fill produced makes implicit representation of fill possible. This forms the basis for a symbolic Givens reduction algorithm that operates in a fixed data structure.

  9. 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.

  10. Coordinated movement of the three rows of outer hair cells is essential for cochlear amplification

    NASA Astrophysics Data System (ADS)

    Murakoshi, Michio; Suzuki, Sho; Wada, Hiroshi

    2015-12-01

    The process known as cochlear amplification is realized by coordinated movement of the outer hair cells (OHCs) in response to changes in their membrane potential. In this process, the displacement amplitude of the basilar membrane (BM) is thought to be increased, thereby leading to the high sensitivity, wide dynamic range and sharp frequency selectivity of our hearing. Unfortunately, however, OHCs are vulnerable to noise exposure, ototoxic acid, aging and so on. Previous studies have shown that exposure to intense noise causes functional loss of OHCs from the innermost row (i.e., close to the modiolus) to the outermost row (i.e., close to the cochlear wall). On the contrary, by other traumatic stimuli such as ototoxic acid, aging and ischemia, such loss of OHCs has been reported to occur from the outermost row toward the innermost row. However, how the cochlear amplification changes when coordinated movement of OHCs is impaired, that is when the OHCs in one, two or all three rows have become dysfunctional, remains unclear. In the present study, therefore, a finite element (FE) model of the gerbil cochlea, which takes the motility of OHCs into account, was developed based on our previous FE model. Using this model, changes in the displacement amplitude of the BM due to the functional loss of OHCs in one, two or all three rows were investigated and the effects of incoordination of the three rows of OHCs on cochlear amplification were estimated. Results showed that the displacement amplitude of the BM significantly decreased when either the innermost row or the outermost row of OHCs lost its function, suggesting that all three rows of OHCs are required for cochlear amplification.

  11. Don't rock the boat: how antiphase crew coordination affects rowing.

    PubMed

    de Brouwer, Anouk J; de Poel, Harjo J; Hofmijster, Mathijs J

    2013-01-01

    It is generally accepted that crew rowing requires perfect synchronization between the movements of the rowers. However, a long-standing and somewhat counterintuitive idea is that out-of-phase crew rowing might have benefits over in-phase (i.e., synchronous) rowing. In synchronous rowing, 5 to 6% of the power produced by the rower(s) is lost to velocity fluctuations of the shell within each rowing cycle. Theoretically, a possible way for crews to increase average boat velocity is to reduce these fluctuations by rowing in antiphase coordination, a strategy in which rowers perfectly alternate their movements. On the other hand, the framework of coordination dynamics explicates that antiphase coordination is less stable than in-phase coordination, which may impede performance gains. Therefore, we compared antiphase to in-phase crew rowing performance in an ergometer experiment. Nine pairs of rowers performed a two-minute maximum effort in-phase and antiphase trial at 36 strokes min(-1) on two coupled free-floating ergometers that allowed for power losses to velocity fluctuations. Rower and ergometer kinetics and kinematics were measured during the trials. All nine pairs easily acquired antiphase rowing during the warm-up, while one pair's coordination briefly switched to in-phase during the maximum effort trial. Although antiphase interpersonal coordination was indeed less accurate and more variable, power production was not negatively affected. Importantly, in antiphase rowing the decreased power loss to velocity fluctuations resulted in more useful power being transferred to the ergometer flywheels. These results imply that antiphase rowing may indeed improve performance, even without any experience with antiphase technique. Furthermore, it demonstrates that although perfectly synchronous coordination may be the most stable, it is not necessarily equated with the most efficient or optimal performance.

  12. Phantom based evaluation of CT to CBCT image registration for proton therapy dose recalculation

    NASA Astrophysics Data System (ADS)

    Landry, Guillaume; Dedes, George; Zöllner, Christoph; Handrack, Josefine; Janssens, Guillaume; Orban de Xivry, Jonathan; Reiner, Michael; Paganelli, Chiara; Riboldi, Marco; Kamp, Florian; Söhn, Matthias; Wilkens, Jan J.; Baroni, Guido; Belka, Claus; Parodi, Katia

    2015-01-01

    The ability to perform dose recalculation on the anatomy of the day is important in the context of adaptive proton therapy. The objective of this study was to investigate the use of deformable image registration (DIR) and cone beam CT (CBCT) imaging to generate the daily stopping power distribution of the patient. We investigated the deformation of the planning CT scan (pCT) onto daily CBCT images to generate a virtual CT (vCT) using a deformable phantom designed for the head and neck (H & N) region. The phantom was imaged at a planning CT scanner in planning configuration, yielding a pCT and in deformed, treatment day configuration, yielding a reference CT (refCT). The treatment day configuration was additionally scanned at a CBCT scanner. A Morphons DIR algorithm was used to generate a vCT. The accuracy of the vCT was evaluated by comparison to the refCT in terms of corresponding features as identified by an adaptive scale invariant feature transform (aSIFT) algorithm. Additionally, the vCT CT numbers were compared to those of the refCT using both profiles and regions of interest and the volumes and overlap (DICE coefficients) of various phantom structures were compared. The water equivalent thickness (WET) of the vCT, refCT and pCT were also compared to evaluate proton range differences. Proton dose distributions from the same initial fluence were calculated on the refCT, vCT and pCT and compared in terms of proton range. The method was tested on a clinical dataset using a replanning CT scan acquired close in time to a CBCT scan as reference using the WET evaluation. Results from the aSIFT investigation suggest a deformation accuracy of 2-3 mm. The use of the Morphon algorithm did not distort CT number intensity in uniform regions and WET differences between vCT and refCT were of the order of 2% of the proton range. This result was confirmed by proton dose calculations. The patient results were consistent with phantom observations. In conclusion, our phantom

  13. SU-E-T-70: Commissioning a Multislice CT Scanner for X-Ray CT Polymer Gel Dosimetry

    SciTech Connect

    Johnston, H; Hilts, M; Jirasek, A

    2014-06-01

    Purpose: To commission a multislice computed tomography (CT) scanner for fast and reliable readout of radiation therapy (RT) dose distributions using CT polymer gel dosimetry (PGD). Methods: Commissioning was performed for a 16-slice CT scanner using images acquired through a 1L cylinder filled with water. Additional images were collected using a single slice machine for comparison purposes. The variability in CT number associated with the anode heel effect was evaluated and used to define a new slice-by-slice background image subtraction technique. Image quality was assessed for the multislice system by comparing image noise and uniformity to that of the single slice machine. The consistency in CT number across slices acquired simultaneously using the multislice detector array was also evaluated. Finally, the variability in CT number due to increasing x-ray tube load was measured for the multislice scanner and compared to the tube load effects observed on the single slice machine. Results: Slice-by-slice background subtraction effectively removes the variability in CT number across images acquired simultaneously using the multislice scanner and is the recommended background subtraction method when using a multislice CT system. Image quality for the multislice machine was found to be comparable to that of the single slice scanner. Further study showed CT number was consistent across image slices acquired simultaneously using the multislice detector array for each detector configuration of the slice thickness examined. In addition, the multislice system was found to eliminate variations in CT number due to increasing x-ray tube load and reduce scanning time by a factor of 4 when compared to imaging a large volume using a single slice scanner. Conclusion: A multislice CT scanner has been commissioning for CT PGD, allowing images of an entire dose distribution to be acquired in a matter of minutes. Funding support provided by the Natural Sciences and Engineering

  14. Test of 3D CT reconstructions by EM + TV algorithm from undersampled data

    NASA Astrophysics Data System (ADS)

    Evseev, Ivan; Ahmann, Francielle; da Silva, Hamilton P.; Schelin, Hugo R.; Yevseyeva, Olga; Klock, Márgio C. L.

    2013-05-01

    Computerized tomography (CT) plays an important role in medical imaging for diagnosis and therapy. However, CT imaging is connected with ionization radiation exposure of patients. Therefore, the dose reduction is an essential issue in CT. In 2011, the Expectation Maximization and Total Variation Based Model for CT Reconstruction (EM+TV) was proposed. This method can reconstruct a better image using less CT projections in comparison with the usual filtered back projection (FBP) technique. Thus, it could significantly reduce the overall dose of radiation in CT. This work reports the results of an independent numerical simulation for cone beam CT geometry with alternative virtual phantoms. As in the original report, the 3D CT images of 128×128×128 virtual phantoms were reconstructed. It was not possible to implement phantoms with lager dimensions because of the slowness of code execution even by the CORE i7 CPU.

  15. Test of 3D CT reconstructions by EM + TV algorithm from undersampled data

    SciTech Connect

    Evseev, Ivan; Ahmann, Francielle; Silva, Hamilton P. da

    2013-05-06

    Computerized tomography (CT) plays an important role in medical imaging for diagnosis and therapy. However, CT imaging is connected with ionization radiation exposure of patients. Therefore, the dose reduction is an essential issue in CT. In 2011, the Expectation Maximization and Total Variation Based Model for CT Reconstruction (EM+TV) was proposed. This method can reconstruct a better image using less CT projections in comparison with the usual filtered back projection (FBP) technique. Thus, it could significantly reduce the overall dose of radiation in CT. This work reports the results of an independent numerical simulation for cone beam CT geometry with alternative virtual phantoms. As in the original report, the 3D CT images of 128 Multiplication-Sign 128 Multiplication-Sign 128 virtual phantoms were reconstructed. It was not possible to implement phantoms with lager dimensions because of the slowness of code execution even by the CORE i7 CPU.

  16. Characterization of suppressor T cells for antibody production by chicken spleen cells. II. Comparison of CT8+ cells from concanavalin A-injected normal and bursa cell-injected agammaglobulinaemic chickens.

    PubMed Central

    Quere, P; Bhogal, B S; Thorbecke, G J

    1990-01-01

    The phenotypes of two different types of suppressor T cells in the chicken, both capable of inhibiting secondary antibody responses in vitro, were determined. The first of these, induced by injection of concanavalin A (Con A) into normal chickens, was CT8+, TcR2+ (alpha beta), CT4-, TcR1- (gamma delta). These cells appeared to exhibit histamine type 2 (H2) receptors, as they adhered to cimetidine-BSA-coated dishes. Moreover, cimetidine added to the medium at 2 x 10(-4) M completely prevented the suppression induced by these suppressor cells. The second type of 'suppressor' T-cell studied, induced in agammaglobulinaemic (A gamma) chickens by injection of bursa cells, exhibited the same phenotype, but was insensitive to cimetidine and did not adhere to cimetidine-BSA-coated dishes, indicating heterogeneity with respect to H2 receptor expression on CT8+ chicken T cells with suppressor activity. The results also showed that a relatively larger proportion of CT8+ than of CT4+ cells adhered to cimetidine-BSA-coated dishes and thus appeared to be H2 receptor positive. TcR1 (gamma delta) cells did not contribute significantly to the antigen non-specific suppressor effects examined in this study. PMID:2149123

  17. Pseudopotential-Based Correlation Consistent Composite Approach (rp-ccCA) for First- and Second-Row Transition Metal Thermochemistry.

    PubMed

    Manivasagam, Sivabalan; Laury, Marie L; Wilson, Angela K

    2015-07-01

    The relativistic-pseudopotential correlation consistent composite approach (rp-ccCA) was used to determine the enthalpy of formation (ΔHf) of 24 first row (3d) transition metal compounds. The rp-ccCA-derived ΔHf's were compared to ΔHf's previously obtained with an all-electron composite method for transition metals (ccCA-TM). For the 3d metal systems, rp-ccCA achieves transition metal accuracy, within 3 kcal/mol of reliable experimental data, overall. By utilizing pseudopotentials within the rp-ccCA methodology, we observed a significant computational time savings (53%) in comparison to the all-electron basis sets employed within ccCA-TM. With the proven reliability and accuracy of rp-ccCA, the methodology was employed to construct a calibration set of 210 second-row (4d) transition metal compounds and their ΔHf's. The 4d calibration set is referred to as 4dHf-210. Within the 4dHf-210 set, there were 61 molecules with available experimental data. The average experimental uncertainty was 4.05 kcal/mol and the mean absolute deviation of rp-ccCA was 3.64 kcal/mol, excluding outliers (10 total). This study provides a large set of energetics that can be used to gauge existing and future computational methodologies and to aid experimentalists in reaction design. PMID:26000954

  18. Effect of inter-row cultivation on soil CO2 emission in a peach plantation

    NASA Astrophysics Data System (ADS)

    Tóth, E.; Farkas, Cs.; Gelybó, Gy.; Lagzi, I.

    2012-04-01

    We examined the effect of inter-row cultivation on soil CO2 emission in a peach plantation planted in 1991. The soil is Ramann type brown forest soil /Mollic Cambisol/ developed on sandy loam. Every second row in the orchard is covered with undisturbed grass, and every other row is disked (depth: 12-15cm) with a two-three-week frequency. The humus content varies from 1,69% to 2,28% in the upper 20 cm layer, where the sand, loam and clay contents are 58%, 21% and 19 %, respectively. The average annual precipitation total is 570 mm (330 mm for the growing season) at the site. During the vegetation period of 2009 soil CO2 emission measurements were carried out with static chamber method in the differently managed rows. Parallel with CO2 measurements soil volumetric water content and soil temperature were also determined. Soil microbiological properties water-extractable organic carbon (WEOC) and water-extractable nitrogen (WEN) as well as substrate-induced respiration (SIR) were determined from disturbed soil samples collected on the first measurement day. The measured soil physical properties showed that different soil management practices influence soil water content, bulk density and soil temperature as well. Soil water content was higher in the grass covered row on 10 of the 13 measurement days, the difference - which reached 10 v% - was the highest on the warmest days. Soil temperature is also different in case of disked and grass covered rows, found to be lower in the grass covered rows on every measurement days. SIR, WEOC and WEN were all higher in the grass covered row (19.45 μg CO2-C g-1 soil 36.91 μg g-1 soil, 139.36 μg g-1 soil, respectively) than in the disked row (4.88 μg CO2-C g-1 soil 25.43 μg C g-1 soil, 61.25 μg N g-1 soil, respectively) in 2009. Soil CO2 emission also differed between the two rows, grass covered rows produced higher emission in all measurements days without exemption. The difference between CO2 fluxes from the two cultivation

  19. Realistic evaluation of hull performance for rowing shells, canoes, and kayaks in unsteady flow.

    PubMed

    Day, Alexander; Campbell, Ian; Clelland, David; Doctors, Lawrence J; Cichowicz, Jakub

    2011-07-01

    In this study, we investigated the effect of hull dynamics in shallow water on the hydrodynamic performance of rowing shells as well as canoes and kayaks. An approach was developed to generate data in a towing tank using a test rig capable of reproducing realistic speed profiles. The impact of unsteady shallow-water effects on wave-making resistance was examined via experimental measurements on a benchmark hull. The data generated were used to explore the validity of a computational approach developed to predict unsteady shallow-water wave resistance. Comparison of measured and predicted results showed that the computational approach correctly predicted complex unsteady wave-resistance phenomena at low oscillation frequency and speed, but that total resistance was substantially under-predicted at moderate oscillation frequency and speed. It was postulated that this discrepancy arose from unsteady viscous effects. This was investigated via hot-film measurements for a full-scale single scull in unsteady flow in both towing-tank and field-trial conditions. Results suggested a strong link between acceleration and turbulence and demonstrated that the measured real-world viscous-flow behaviour could be successfully reproduced in the tank. Thus a suitable tank-test approach could provide a reliable guide to hull performance characterization in unsteady flow. PMID:21756127

  20. A Three-Dimensional Linearized Unsteady Euler Analysis for Turbomachinery Blade Rows

    NASA Technical Reports Server (NTRS)

    Montgomery, Matthew D.; Verdon, Joseph M.

    1997-01-01

    A three-dimensional, linearized, Euler analysis is being developed to provide an efficient unsteady aerodynamic analysis that can be used to predict the aeroelastic and aeroacoustic responses of axial-flow turbo-machinery blading.The field equations and boundary conditions needed to describe nonlinear and linearized inviscid unsteady flows through a blade row operating within a cylindrical annular duct are presented. A numerical model for linearized inviscid unsteady flows, which couples a near-field, implicit, wave-split, finite volume analysis to a far-field eigenanalysis, is also described. The linearized aerodynamic and numerical models have been implemented into a three-dimensional linearized unsteady flow code, called LINFLUX. This code has been applied to selected, benchmark, unsteady, subsonic flows to establish its accuracy and to demonstrate its current capabilities. The unsteady flows considered, have been chosen to allow convenient comparisons between the LINFLUX results and those of well-known, two-dimensional, unsteady flow codes. Detailed numerical results for a helical fan and a three-dimensional version of the 10th Standard Cascade indicate that important progress has been made towards the development of a reliable and useful, three-dimensional, prediction capability that can be used in aeroelastic and aeroacoustic design studies.

  1. Numerical Simulations of Steady and Unsteady Transition in Low-Pressure Turbine Blade Rows

    NASA Technical Reports Server (NTRS)

    Dorney, Daniel

    1998-01-01

    Transition plays an important role in the prediction of losses and performance in low-pressure turbines. The transition location on a turbine blade may vary significantly because of the wakes from upstream blade rows, and intermittent flow separation can also affect the transition process in an unsteady flow environment. In the present investigation, an unsteady Navier-Stokes analysis is used to predict transition in a low-pressure turbine cascade and a low-pressure turbine stage. The numerical flow analysis is third-order spatially accurate and second-order temporally accurate, and the equations of motion are integrated using an implicit time-marching procedure. The Baldwin-Lomax and k-epsilon turbulence models, in conjunction with several algebraic transition models, have been used to predict the location of transition. Predicted results include unsteady blade loadings, time-histories of the pressure, transition locations and boundary layer quantities, as well as performance quantities and comparisons with the available experimental/design data.

  2. Is death row obsolete? A decade of mainstreaming death-sentenced inmates in Missouri.

    PubMed

    Cunningham, Mark D; Reidy, Thomas J; Sorensen, Jon R

    2005-01-01

    Death-sentenced inmates in Missouri have been integrated or "mainstreamed" into the general population of the Potosi Correctional Center since 1991. By comparing the rate of violent misconduct among these mainstreamed death-sentenced inmates with that of the life-without-parole and parole eligible inmates under fully integrated conditions of confinement, this study provides the first empirical (statistical) evaluation of this innovative alternative to segregated death row confinement. The mainstreamed death-sentenced inmates committed no inmate or staff homicides, or attempted homicides. Comparison of their rates of institutional violence revealed frequencies that were similar to those of life-without-parole inmates, and well below those of fellow inmates who were sentenced to parole eligible terms. These findings cast serious doubt on the security-driven assumptions that have typified the segregation of death-sentenced inmates and have dictated highly restrictive confinement policies for this group. A conclusion that death-sentenced inmates can be safely integrated into a general prison population has significant implications for allocation of scarce fiscal resources and correctional staff, as well as for inmate mental health, particularly given the extended tenure that death-sentenced inmates typically serve between sentencing and relief/execution.

  3. Diagnostic Accuracy of CT Enterography for Active Inflammatory Terminal Ileal Crohn Disease: Comparison of Full-Dose and Half-Dose Images Reconstructed with FBP and Half-Dose Images with SAFIRE.

    PubMed

    Gandhi, Namita S; Baker, Mark E; Goenka, Ajit H; Bullen, Jennifer A; Obuchowski, Nancy A; Remer, Erick M; Coppa, Christopher P; Einstein, David; Feldman, Myra K; Kanmaniraja, Devaraju; Purysko, Andrei S; Vahdat, Noushin; Primak, Andrew N; Karim, Wadih; Herts, Brian R

    2016-08-01

    Purpose To compare the diagnostic accuracy and image quality of computed tomographic (CT) enterographic images obtained at half dose and reconstructed with filtered back projection (FBP) and sinogram-affirmed iterative reconstruction (SAFIRE) with those of full-dose CT enterographic images reconstructed with FBP for active inflammatory terminal or neoterminal ileal Crohn disease. Materials and Methods This retrospective study was compliant with HIPAA and approved by the institutional review board. The requirement to obtain informed consent was waived. Ninety subjects (45 with active terminal ileal Crohn disease and 45 without Crohn disease) underwent CT enterography with a dual-source CT unit. The reference standard for confirmation of active Crohn disease was active terminal ileal Crohn disease based on ileocolonoscopy or established Crohn disease and imaging features of active terminal ileal Crohn disease. Data from both tubes were reconstructed with FBP (100% exposure); data from the primary tube (50% exposure) were reconstructed with FBP and SAFIRE strengths 3 and 4, yielding four datasets per CT enterographic examination. The mean volume CT dose index (CTDIvol) and size-specific dose estimate (SSDE) at full dose were 13.1 mGy (median, 7.36 mGy) and 15.9 mGy (median, 13.06 mGy), respectively, and those at half dose were 6.55 mGy (median, 3.68 mGy) and 7.95 mGy (median, 6.5 mGy). Images were subjectively evaluated by eight radiologists for quality and diagnostic confidence for Crohn disease. Areas under the receiver operating characteristic curves (AUCs) were estimated, and the multireader, multicase analysis of variance method was used to compare reconstruction methods on the basis of a noninferiority margin of 0.05. Results The mean AUCs with half-dose scans (FBP, 0.908; SAFIRE 3, 0.935; SAFIRE 4, 0.924) were noninferior to the mean AUC with full-dose FBP scans (0.908; P < .003). The proportion of images with inferior quality was significantly higher with all

  4. 77 FR 25077 - Special Local Regulation; Wy-Hi 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; Wy-Hi Rowing Regatta, Trenton... navigable waters immediately prior to, during, and immediately after the Wy-Hi Rowing Regatta. This special....35T09-0342 Special Local Regulation; Wy-Hi Rowing Regatta, Wyandotte, MI. (a) Regulated Area....

  5. 30 CFR 585.308 - How will BOEM conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and RUE grants? 585.308 Section 585.308 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Obtaining Row Grants and Rue Grants § 585.308 How will BOEM conduct an auction for ROW grants and RUE grants... to comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The...

  6. 30 CFR 585.302 - What are the general requirements for ROW grant and RUE grant holders?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and RUE grant holders? 585.302 Section 585.302 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Row Grants and Rue Grants § 585.302 What are the general requirements for ROW grant and RUE grant holders? (a) To acquire an ROW grant or RUE grant you must provide evidence that you meet...

  7. 30 CFR 585.315 - What deposits are required for a competitive ROW grant or RUE grant?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ROW grant or RUE grant? 585.315 Section 585.315 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Financial Requirements for Row Grants and Rue Grants § 585.315 What deposits are required for a competitive ROW grant or RUE grant? (a) You must make a deposit, as required in § 585.501(a), regardless...

  8. 30 CFR 585.302 - What are the general requirements for ROW grant and RUE grant holders?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and RUE grant holders? 585.302 Section 585.302 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Row Grants and Rue Grants § 585.302 What are the general requirements for ROW grant and RUE grant holders? (a) To acquire an ROW grant or RUE grant you must provide evidence that you meet...

  9. 30 CFR 585.307 - How will BOEM determine whether competitive interest exists for ROW grants and RUE grants?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... interest exists for ROW grants and RUE grants? 585.307 Section 585.307 Mineral Resources BUREAU OF OCEAN... Renewable Energy Activities Obtaining Row Grants and Rue Grants § 585.307 How will BOEM determine whether competitive interest exists for ROW grants and RUE grants? To determine whether or not there is...

  10. 30 CFR 285.307 - How will MMS determine whether competitive interest exists for ROW grants and RUE grants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... interest exists for ROW grants and RUE grants? 285.307 Section 285.307 Mineral Resources MINERALS... Renewable Energy Activities Obtaining Row Grants and Rue Grants § 285.307 How will MMS determine whether competitive interest exists for ROW grants and RUE grants? To determine whether or not there is...

  11. 30 CFR 585.302 - What are the general requirements for ROW grant and RUE grant holders?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and RUE grant holders? 585.302 Section 585.302 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Row Grants and Rue Grants § 585.302 What are the general requirements for ROW grant and RUE grant holders? (a) To acquire an ROW grant or RUE grant you must provide evidence that you meet...

  12. 30 CFR 585.308 - How will BOEM conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and RUE grants? 585.308 Section 585.308 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Obtaining Row Grants and Rue Grants § 585.308 How will BOEM conduct an auction for ROW grants and RUE grants... to comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The...

  13. 30 CFR 585.315 - What deposits are required for a competitive ROW grant or RUE grant?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ROW grant or RUE grant? 585.315 Section 585.315 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Financial Requirements for Row Grants and Rue Grants § 585.315 What deposits are required for a competitive ROW grant or RUE grant? (a) You must make a deposit, as required in § 585.501(a), regardless...

  14. 30 CFR 585.307 - How will BOEM determine whether competitive interest exists for ROW grants and RUE grants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... interest exists for ROW grants and RUE grants? 585.307 Section 585.307 Mineral Resources BUREAU OF OCEAN... Renewable Energy Activities Obtaining Row Grants and Rue Grants § 585.307 How will BOEM determine whether competitive interest exists for ROW grants and RUE grants? To determine whether or not there is...

  15. 30 CFR 585.307 - How will BOEM determine whether competitive interest exists for ROW grants and RUE grants?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... interest exists for ROW grants and RUE grants? 585.307 Section 585.307 Mineral Resources BUREAU OF OCEAN... Renewable Energy Activities Obtaining Row Grants and Rue Grants § 585.307 How will BOEM determine whether competitive interest exists for ROW grants and RUE grants? To determine whether or not there is...

  16. 30 CFR 285.315 - What deposits are required for a competitive ROW grant or RUE grant?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ROW grant or RUE grant? 285.315 Section 285.315 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Renewable Energy Activities Financial Requirements for Row Grants and Rue Grants § 285.315 What deposits are required for a competitive ROW grant or RUE grant? (a) You must make a deposit, as required in §...

  17. 30 CFR 585.308 - How will BOEM conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and RUE grants? 585.308 Section 585.308 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Obtaining Row Grants and Rue Grants § 585.308 How will BOEM conduct an auction for ROW grants and RUE grants... to comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The...

  18. 30 CFR 285.315 - What deposits are required for a competitive ROW grant or RUE grant?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ROW grant or RUE grant? 285.315 Section 285.315 Mineral Resources MINERALS MANAGEMENT SERVICE... Financial Requirements for Row Grants and Rue Grants § 285.315 What deposits are required for a competitive ROW grant or RUE grant? (a) You must make a deposit, as required in § 285.501(a), regardless...

  19. 30 CFR 285.308 - How will MMS conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and RUE grants? 285.308 Section 285.308 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF... Obtaining Row Grants and Rue Grants § 285.308 How will MMS conduct an auction for ROW grants and RUE grants... comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The auction...

  20. 30 CFR 285.302 - What are the general requirements for ROW grant and RUE grant holders?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and RUE grant holders? 285.302 Section 285.302 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Renewable Energy Activities Row Grants and Rue Grants § 285.302 What are the general requirements for ROW grant and RUE grant holders? (a) To acquire an ROW grant or RUE grant you must provide evidence that...