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Sample records for ct number accuracy

  1. Tin-filter enhanced dual-energy-CT: image quality and accuracy of CT numbers in virtual noncontrast imaging.

    Science.gov (United States)

    Kaufmann, Sascha; Sauter, Alexander; Spira, Daniel; Gatidis, Sergios; Ketelsen, Dominik; Heuschmid, Martin; Claussen, Claus D; Thomas, Christoph

    2013-05-01

    To measure and compare the objective image quality of true noncontrast (TNC) images with virtual noncontrast (VNC) images acquired by tin-filter-enhanced, dual-source, dual-energy computed tomography (DECT) of upper abdomen. Sixty-three patients received unenhanced abdominal CT and enhanced abdominal DECT (100/140 kV with tin filter) in portal-venous phase. VNC images were calculated from the DECT datasets using commercially available software. The mean attenuation of relevant tissues and image quality were compared between the TNC and VNC images. Image quality was rated objectively by measuring image noise and the sharpness of object edges using custom-designed software. Measurements were compared using Student two-tailed t-test. Correlation coefficients for tissue attenuation measurements between TNC and VNC were calculated and the relative deviations were illustrated using Bland-Altman plots. Mean attenuation differences between TNC and VNC (HUTNC - HUVNC) image sets were as follows: right liver lobe -4.94 Hounsfield units (HU), left liver lobe -3.29 HU, vena cava -2.19 HU, spleen -7.46 HU, pancreas 1.29 HU, fat -11.14 HU, aorta 1.29 HU, bone marrow 36.83 HU (all P Mean image noise was significantly higher in TNC images (P images (P = .19). The Hounsfield units in VNC images closely resemble TNC images in the majority of the organs of the upper abdomen (kidneys, liver, pancreas). In spleen and fat, Hounsfield numbers in VNC images are tend to be higher than in TNC images. VNC images show a low image noise and satisfactory edge sharpness. Other criteria of image quality and the depiction of certain lesions need to be evaluated additionally. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  2. Fast kVp-switching dual energy contrast-enhanced thorax and cardiac CT: A phantom study on the accuracy of iodine concentration and effective atomic number measurement.

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    Papadakis, Antonios E; Damilakis, John

    2017-09-01

    To assess the effect of vessel diameter and exposure parameters on the estimation accuracy of concentration and effective atomic number (Zeff ) of iodine (I) in contrast-enhanced thorax and cardiac dual-energy CT using a modern fast kVp-switching CT scanner. A standard semi-anthropomorphic cardiac CT phantom devised to simulate the human chest at three different body habitus i.e., medium-sized, large-sized, and obese, was scanned using a fast kVp-switching Revolution-GSI GE CT scanner. Five cylindrical, 10 mm diameter, vials were filled with solutions prepared by diluting I contrast at five concentrations (2.5, 5, 10, 15, and 20 mg I/ml). To simulate small vessels, pipette tips with a diameter ranging from 5 mm to 0.5 mm were employed. The vials and pipette tips were accommodated within the semi-anthropomorphic phantom. CT acquisitions were performed in the fast kVp-switching dual-energy mode at six different CTDIw values. Acquisitions were also performed at 80, 100, 120, and 140 kVp. Images were acquired at 64 × 0.625 mm beam collimation and reconstructed at 2.5 mm using all available reconstruction filter kernels. Virtual monochromatic spectral (VMS) images, iodine concentration (IMeas ), and Zeff maps were reconstructed. Hounsfield unit as a function of energy (HUkeV ) in VMS and single-kVp (HUkVp ), IMeas and Zeff were measured at each CTDIw . The effect of vessel diameter on IMeas and Zeff was investigated. Measured HUkeV and Zeff were compared to theoretically estimated values and IMeas were compared to nominal (INom ) values. In 10 mm diameter vessels, HUkeV values were accurate to 18% for the medium-sized, 22% for the large-sized and 39% for the obese phantoms. IMeas was underestimated by up to 10% for the medium-sized, 26% for the large-sized and 33% for the obese phantom. IMeas error decreased with increasing CTDIw from ±0.799 mg/ml at 8.61 mGy to ±0.082 mg/ml at 32.01 mGy. The percentage difference between measured and theoretically estimated Zeff

  3. Ion stopping powers and CT numbers.

    Science.gov (United States)

    Moyers, Michael F; Sardesai, Milind; Sun, Sean; Miller, Daniel W

    2010-01-01

    One of the advantages of ion beam therapy is the steep dose gradient produced near the ion's range. Use of this advantage makes knowledge of the stopping powers for all materials through which the beam passes critical. Most treatment planning systems calculate dose distributions using depth dose data measured in water and an algorithm that converts the kilovoltage X-ray computed tomography (CT) number of a given material to its linear stopping power relative to water. Some materials present in kilovoltage scans of patients and simulation phantoms do not lie on the standard tissue conversion curve. The relative linear stopping powers (RLSPs) of 21 different tissue substitutes and positioning, registration, immobilization, and beamline materials were measured in beams of protons accelerated to energies of 155, 200, and 250 MeV; carbon ions accelerated to 290 MeV/n; and iron ions accelerated to 970 MeV/n. These same materials were scanned with both kilovoltage and megavoltage CT scanners to obtain their CT numbers. Measured RLSPs and CT numbers were compared with calculated and/or literature values. Relationships of RLSPs to physical densities, electronic densities, kilovoltage CT numbers, megavoltage CT numbers, and water equivalence values converted by a treatment planning system are given. Usage of CT numbers and substitution of measured values into treatment plans to provide accurate patient and phantom simulations are discussed. 2010 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  4. Diagnostic accuracy of CT scan in abdominal blunt trauma

    Institute of Scientific and Technical Information of China (English)

    Javad Salimi; Khadyjeh Bakhtavar; Mehdi Solimani; Patrcia Khashayar; Ali Pasha Meysamie; Moosa Zargar

    2009-01-01

    Obiective: To evaluate the sensitivity and specificity of CT scan findings in Patients ith blunt abdominal trauma admitted to the university hospital.Methods: All the atients ith blunt abdominal trauma admitted at a tertiary teaching trauma center in Iran between 2005 and 2007 were enrolled in this study.In the absence of any clinical anifestations,he patients underwent a diagnostic CT scan.Laparatomy was performed in those with positive CT results.Others were observed for 48 hours and discharged in case no problem as reported;otherwise they underwent laparatomy.Information on patients'demographic ata,mechanism of trauma,indication for CT scan,CT scan findings,results of laparotomy ere gathered.The sensitivity,specificity and accuracy of the CT-scan images in regard ith the organ injured were calculated.The sensitivity,specificity and accuracy of the T scan were calculated in each case.Results: CT Scan had the highest sensitivity for etecting the injuries to liver (100%) and spleen (86.6%).The specificity of the method or detecting retroperitoneal hematoma (100%) and injuries to kidney (93.5%) was higher han other organs.The accuracy of CT images to detect the injuries to spleen,liver,idney and retroperitoneal hematoma was reported to be 96.1%,94.4%,91.6% and 91.6% espectively.Conclusion: The findings of the present study reveal that CT scan could econsidered as a good choice,especially for patients with blunt abdominal trauma in eaching hospitals where the radiologic academic staff is not present in the hospital in the night shifts.

  5. Accuracy of quantitative reconstructions in SPECT/CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbinin, S; Celler, A [Department of Radiology, University of British Columbia, 366-828 West 10th Avenue, Vancouver BC, V5Z 1L8 (Canada); Belhocine, T; Vanderwerf, R; Driedger, A [Department of Nuclear Medicine, London Health Sciences Centre, 375 South Street, PO Box 5375, London ON, N6A 4G5 (Canada)], E-mail: shcher2@interchange.ubc.ca

    2008-09-07

    The goal of this study was to determine the quantitative accuracy of our OSEM-APDI reconstruction method based on SPECT/CT imaging for Tc-99m, In-111, I-123, and I-131 isotopes. Phantom studies were performed on a SPECT/low-dose multislice CT system (Infinia-Hawkeye-4 slice, GE Healthcare) using clinical acquisition protocols. Two radioactive sources were centrally and peripherally placed inside an anthropometric Thorax phantom filled with non-radioactive water. Corrections for attenuation, scatter, collimator blurring and collimator septal penetration were applied and their contribution to the overall accuracy of the reconstruction was evaluated. Reconstruction with the most comprehensive set of corrections resulted in activity estimation with error levels of 3-5% for all the isotopes.

  6. Influence of chamber misalignment on cased telescoped (CT) ammunition accuracy

    Institute of Scientific and Technical Information of China (English)

    D. CORRIVEAU; C. FLORIN PETRE

    2016-01-01

    As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT) ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

  7. Influence of chamber misalignment on cased telescoped (CT ammunition accuracy

    Directory of Open Access Journals (Sweden)

    D. Corriveau

    2016-04-01

    Full Text Available As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

  8. Anastomotic leakage after colorectal surgery: diagnostic accuracy of CT

    Energy Technology Data Exchange (ETDEWEB)

    Kauv, Paul; Benadjaoud, Samir; Boulay-Coletta, Isabelle; Zins, Marc [Fondation Hopital Saint-Joseph, Department of Radiology, Paris (France); Curis, Emmanuel [Universite Paris Descartes, Laboratoire de biomathematiques, Faculte de pharmacie, Paris (France); Loriau, Jerome [Fondation Hopital Saint-Joseph, Department of Digestive Surgery, Paris (France)

    2015-12-15

    To evaluate the diagnostic accuracy of CT in postoperative colorectal anastomotic leakage (AL). Two independent blinded radiologists reviewed 153 CTs performed for suspected AL within 60 days after surgery in 131 consecutive patients, with (n = 58) or without (n = 95) retrograde contrast enema (RCE). Results were compared to original interpretations. The reference standard was reoperation or consensus (a radiologist and a surgeon) regarding clinical, laboratory, radiological, and follow-up data after medical treatment. AL was confirmed in 34/131 patients. For the two reviewers and original interpretation, sensitivity of CT was 82 %, 87 %, and 71 %, respectively; specificity was 84 %, 84 %, and 92 %. RCE significantly increased the positive predictive value (from 40 % to 88 %, P = 0.0009; 41 % to 92 %, P = 0.0016; and 40 % to 100 %, P = 0.0006). Contrast extravasation was the most sensitive (reviewers, 83 % and 83 %) and specific (97 % and 97 %) sign and was significantly associated with AL by univariate analysis (P < 0.0001 and P < 0.0001). By multivariate analysis with recursive partitioning, CT with RCE was accurate to confirm or rule out AL with contrast extravasation. CT with RCE is accurate for diagnosing postoperative colorectal AL. Contrast extravasation is the most reliable sign. RCE should be performed during CT for suspected AL. (orig.)

  9. Diagnostic accuracy of CT angiography in acute gastrointestinal bleeding.

    Science.gov (United States)

    Chua, A E; Ridley, L J

    2008-08-01

    The aim of the study was to carry out a systematic review determining the accuracy of CT angiography in the diagnosis of acute gastrointestinal bleeding. A search of published work in Medline and manual searching of reference lists of articles was conducted. Studies were included if they compared CT angiography to a reference standard of upper gastrointestinal endoscopy, colonoscopy, angiography or surgery in the diagnosis of acute gastrointestinal bleeding. Eight published studies evaluating 129 patients were included. Data were used to form 2 x 2 tables. Computed tomography angiography showed pooled sensitivity of 86% (95% confidence interval 78-92%) and specificity of 95% (95% confidence interval 76-100%), without showing significant heterogeneity (chi(2) = 3.5, P = 0.6) and (chi(2) = 5.4, P = 0.6), respectively. Summary receiver operating characteristic analysis showed an area under the curve of 0.93. Computed tomography angiography is accurate in the diagnosis of acute gastrointestinal bleeding and can show the precise location and aetiology of bleeding, thereby directing further management. Strong recommendations for use of CT cannot be made from this review because of the methodological limitations and further large prospective studies are needed to define the role of CT in acute gastrointestinal bleeding.

  10. CT Angiography for Living Kidney Donors: Accuracy, Cause of Misinterpretation and Prevalence of Variation

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Jee Won; Lee, Whal; Yin, Yong Hu; Jae, Hwan Jun; Chung, Jin Wook; Park, Jae Hyung [Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Hyeon Hoe [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2008-08-15

    To determine the accuracy of the use of multi-detector row CT (MDCT) to predict vascular anatomy in living kidney donors and to reveal the prevalence of vascular variations in a Korean population. A total of 153 living kidney donors that had undergone preoperative CT and nephrectomy, either with open or laparoscopic surgery, were selected retrospectively. The initial CT results were compared with the surgical findings and repeated review sessions of CT scans were performed to determine the causes of mismatches in discordant cases. The accuracy of CT angiography was 95% to predict the number of renal vessels. Four arteries and two veins were missed during the initial CT interpretation due to perception errors (for two arteries and two veins) and technical limitations (two arteries). The prevalence of multiple renal arteries and veins, early branching of a renal artery and late confluence of a renal vein were 31%, 5%, 12%, 17%, respectively. The circumaortic renal vein and the bilateral inferior vena cava were found in two cases each (1.3%). One case (0.7%) each of a retroaortic renal vein and a supradiaphragmatic originated renal artery were found. MDCT provides a reliable method to evaluate the vascular anatomy and variations of living kidney donors.

  11. Energy Dependence of Measured CT Numbers on Substituted Materials Used for CT Number Calibration of Radiotherapy Treatment Planning Systems

    Science.gov (United States)

    Mahmoudi, Reza; Jabbari, Nasrollah; aghdasi, Mehdi; Khalkhali, Hamid Reza

    2016-01-01

    Introduction For accurate dose calculations, it is necessary to provide a correct relationship between the CT numbers and electron density in radiotherapy treatment planning systems (TPSs). The purpose of this study was to investigate the energy dependence of measured CT numbers on substituted materials used for CT number calibration of radiotherapy TPSs and the resulting errors in the treatment planning calculation doses. Materials and Methods In this study, we designed a cylindrical water phantom with different materials used as tissue equivalent materials for the simulation of tissues and obtaining the related CT numbers. For evaluating the effect of CT number variations of substituted materials due to energy changing of scanner (kVp) on the dose calculation of TPS, the slices of the scanned phantom at three kVp's were imported into the desired TPSs (MIRS and CorePLAN). Dose calculations were performed on two TPSs. Results The mean absolute percentage differences between the CT numbers of CT scanner and two treatment planning systems for all the samples were 3.22%±2.57% for CorePLAN and 2.88%±2.11% for MIRS. It was also found that the maximum absolute percentage difference between all of the calculated doses from each photon beam of linac (6 and 15 MV) at three kVp's was less than 1.2%. Discussion The present study revealed that, for the materials with effective low atomic number, the mean CT number increased with increasing energy, which was opposite for the materials with an effective high atomic number. We concluded that the tissue substitute materials had a different behavior in the energy ranges from 80 to 130 kVp. So, it is necessary to consider the energy dependence of the substitute materials used for the measurement or calibration of CT number for radiotherapy treatment planning systems. PMID:27391672

  12. Surface-based registration accuracy of CT-based image-guided spine surgery.

    Science.gov (United States)

    Tamura, Yuichi; Sugano, Nobuhiko; Sasama, Toshihiko; Sato, Yoshinobu; Tamura, Shinichi; Yonenobu, Kazuo; Yoshikawa, Hideki; Ochi, Takahiro

    2005-04-01

    Registration is a critical and important process in maintaining the accuracy of CT-based image-guided surgery. The aim of this study was to evaluate the effects of the area of intraoperative data sampling and number of sampling points on the accuracy of surface-based registration in a CT-based spinal-navigation system, using an optical three-dimensional localizer. A cadaveric dry-bone phantom of the lumbar spine was used. To evaluate registration accuracy, three alumina ceramic balls were attached to the anterior and lateral aspects of the vertebral body. CT images of the phantom were obtained (1-mm slice thickness, at1-mm intervals) using a helical CT scanner. Twenty surface points were digitized from five zones defined on the basis of anatomical classification on the posterior aspects of the target vertebra. A total of 20 sets of sampling data were obtained. Evaluation of registration accuracy accounted for positional and rotational errors. Of the five zones, the area that was the largest and easiest to expose surgically and to digitize surface points was the lamina. The lamina was defined as standard zone. On this zone, the effect of the number of sampling points on the positional and rotational accuracy of registration was evaluated. And the effects of the additional area selected for intraoperative data sampling on the registration accuracy were evaluated. Using 20 surface points on the posterior side of the lamina, positional error was 0.96 mm +/- 0.24 mm root-mean-square (RMS) and rotational error was 0.91 degrees +/- 0.38 degrees RMS. The use of 20 surface points on the lamina usually allows surgeons to carry out sufficiently accurate registration to conduct computer-aided spine surgery. In the case of severe spondylosis, however, it might be difficult to digitize the surface points from the lamina, due to a hypertrophic facet joint or the deformity of the lamina and noisy sampling data. In such cases, registration accuracy can be improved by combining use

  13. Reassessment of CT images to improve diagnostic accuracy in patients with suspected acute appendicitis and an equivocal preoperative CT interpretation

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    Kim, Hyun Cheol; Yang, Dal Mo; Kim, Sang Won [Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Department of Radiology, Seoul (Korea, Republic of); Park, Seong Jin [Kyung Hee University Hospital, College of Medicine, Kyung Hee University, Department of Radiology, Seoul (Korea, Republic of)

    2012-06-15

    To identify CT features that discriminate individuals with and without acute appendicitis in patients with equivocal CT findings, and to assess whether knowledge of these findings improves diagnostic accuracy. 53 patients that underwent appendectomy with an indeterminate preoperative CT interpretation were selected and allocated to an acute appendicitis group or a non-appendicitis group. The 53 CT examinations were reviewed by two radiologists in consensus to identify CT findings that could aid in the discrimination of those with and without appendicitis. In addition, two additional radiologists were then requested to evaluate independently the 53 CT examinations using a 4-point scale, both before and after being informed of the potentially discriminating criteria. CT findings found to be significantly different in the two groups were; the presence of appendiceal wall enhancement, intraluminal air in appendix, a coexistent inflammatory lesion, and appendiceal wall thickening (P < 0.05). Areas under the curves of reviewers 1 and 2 significantly increased from 0.516 and 0.706 to 0.677 and 0.841, respectively, when reviewers were told which CT variables were significant (P = 0.0193 and P = 0.0397, respectively). Knowledge of the identified CT findings was found to improve diagnostic accuracy for acute appendicitis in patients with equivocal CT findings. circle Numerous patients with clinically equivocal appendicitis do not have acute appendicitis circle Computed tomography (CT) helps to reduce the negative appendectomy rate circle CT is not always infallible and may also demonstrate indeterminate findings circle However knowledge of significant CT variables can further reduce negative appendectomy rate circle An equivocal CT interpretation of appendicitis should be reassessed with this knowledge. (orig.)

  14. Monte Carlo Simulations: Number of Iterations and Accuracy

    Science.gov (United States)

    2015-07-01

    Jessica Schultheis for her editorial review. vi INTENTIONALLY LEFT BLANK. 1 1. Introduction Monte Carlo (MC) methods1 are often used...ARL-TN-0684 ● JULY 2015 US Army Research Laboratory Monte Carlo Simulations: Number of Iterations and Accuracy by William...needed. Do not return it to the originator. ARL-TN-0684 ● JULY 2015 US Army Research Laboratory Monte Carlo Simulations: Number

  15. Staging accuracy of pancreatic cancer: Comparison between non-contrast-enhanced and contrast-enhanced PET/CT

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    Yoneyama, Tomohiro [Department of Radiology, Yokohama City University, Graduate School of Medicine, Yokohama (Japan); Tateishi, Ukihide, E-mail: utateish@yokohama-cu.ac.jp [Department of Radiology, Yokohama City University, Graduate School of Medicine, Yokohama (Japan); Endo, Itaru [Department of Surgery, Yokohama City University, Graduate School of Medicine, Yokohama (Japan); Inoue, Tomio [Department of Radiology, Yokohama City University, Graduate School of Medicine, Yokohama (Japan)

    2014-10-15

    Purpose: Our aim was to clarify the diagnostic impact of contrast-enhanced (CE) {sup 18}F-fluorodeoxyglucose (FDG)–positron emission tomography (PET)/computed tomography (CT) for staging of pancreatic cancer compared to non-CE PET/CT. Method and materials: Between April 2006 and November 2009, a total of 95 patients (age range, 36–83 years [mean age, 67]) with primary pancreatic cancer underwent {sup 18}F-FDG PET/CT examinations. Diagnostic accuracy was compared between non-CE PET/CT and CE PET/CT. Images were analyzed visually and quantitatively by two blinded reviewers. Reference standard was histological examination in 48 patients (51%) and/or confirmation of an obvious progression in number and/or size of the lesions on follow-up CT examinations in 47 patients (49%). Results: For T-staging, invasion of duodenum (n = 20, 21%), mesentery (n = 12, 13%), and retroperitoneum (n = 13, 14%) was correctly diagnosed by both modalities. The ROC analyses revealed that the Az values of celiac artery (CA), common hepatic artery (CHA), splenic artery (SV), and superior mesenteric vein (SMV) invasion were significantly higher in the CE PET/CT group for both readers. Nodal metastasis was correctly diagnosed by CE PET/CT in 38 patients (88%) and by non-CE PET/CT in 45 patients (87%). Diagnostic accuracies of nodal metastasis in two modalities were similar. Using CE PET/CT, distant metastasis, scalene node metastasis, and peritoneal dissemination were correctly assigned in 39 patients (91%), while interpretation based on non-CE PET/CT revealed distant metastasis, scalene node metastasis, and peritoneal dissemination in 42 patients (81%). Diagnostic accuracy of distant metastasis, scalene node metastasis, and peritoneal dissemination with CE PET/CT was significantly higher than that of non-CE PET/CT (p < 0.05). Conclusion: CE PET/CT allows a more precise assessment of distant metastasis, scalene node metastasis, and peritoneal dissemination in patients with pancreatic cancer.

  16. Spectral performance of a whole-body research photon counting detector CT: quantitative accuracy in derived image sets

    Science.gov (United States)

    Leng, Shuai; Zhou, Wei; Yu, Zhicong; Halaweish, Ahmed; Krauss, Bernhard; Schmidt, Bernhard; Yu, Lifeng; Kappler, Steffen; McCollough, Cynthia

    2017-09-01

    Photon-counting computed tomography (PCCT) uses a photon counting detector to count individual photons and allocate them to specific energy bins by comparing photon energy to preset thresholds. This enables simultaneous multi-energy CT with a single source and detector. Phantom studies were performed to assess the spectral performance of a research PCCT scanner by assessing the accuracy of derived images sets. Specifically, we assessed the accuracy of iodine quantification in iodine map images and of CT number accuracy in virtual monoenergetic images (VMI). Vials containing iodine with five known concentrations were scanned on the PCCT scanner after being placed in phantoms representing the attenuation of different size patients. For comparison, the same vials and phantoms were also scanned on 2nd and 3rd generation dual-source, dual-energy scanners. After material decomposition, iodine maps were generated, from which iodine concentration was measured for each vial and phantom size and compared with the known concentration. Additionally, VMIs were generated and CT number accuracy was compared to the reference standard, which was calculated based on known iodine concentration and attenuation coefficients at each keV obtained from the U.S. National Institute of Standards and Technology (NIST). Results showed accurate iodine quantification (root mean square error of 0.5 mgI/cc) and accurate CT number of VMIs (percentage error of 8.9%) using the PCCT scanner. The overall performance of the PCCT scanner, in terms of iodine quantification and VMI CT number accuracy, was comparable to that of EID-based dual-source, dual-energy scanners.

  17. 78 FR 7848 - Connecticut Disaster Number CT-00028

    Science.gov (United States)

    2013-02-04

    ... ADMINISTRATION Connecticut Disaster Number CT-00028 AGENCY: U.S. Small Business Administration. ACTION: Amendment...: U.S. Small Business Administration, Processing and Disbursement Center, 14925 Kingsport Road, Fort... Business Administration, 409 3rd Street SW., Suite 6050, Washington, DC 20416. SUPPLEMENTARY...

  18. Accuracy Enhancement of CT Measurements using Data Filtering

    DEFF Research Database (Denmark)

    Stolfi, Alessandro; Kallasse, Maarja-Helena; Carli, Lorenzo

    2016-01-01

    This paper describes the impact of data filtering on CT capability to inspect assemblies. The investigation was carried out using an industrial multi-material assembly provided by Novo Nordisk A/S. The assembly comprises two parts made of polyoxymethylene (POM) and of an alloy comprising polycarb...

  19. CT-discography; diagnostic accuracy in lumbar disc herniation and significance of induced pain during procedure

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    Jin, En Hao [Yan Bian Medical College, Beijing (China); Chung, Tae Sub; Jeong, Mi Gyoung; Kim, Young Soo; Roh, Sung Woo [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-01-01

    To evaluate the usefulness and the accuracy of CT-discography in lumbar disc disease by analyzing the findings of CT-discogram and types of evoked pain during the procedure. CT-discograms were retrospectively evaluated in 47 intervertebral discs of 20 patients with multilevel involvement of lumbar disc diseases. In 28 herniated discs confirmed at surgery, the findings of CT-discogram (28 disc levels/20 patients), MRI(23/16) and CT(21/15) were comparatively analysed. The type of pain after infusion of contrast media during CT-discography was compared with that prior to the procedure. The accuracy for determining types of the herniated lumbar disc when compared with post-operative results was 96.4%(27 discs/28 discs) in the CT-discogram, 82.6%(19 discs/23 discs) in MRI and 71.4%(15 discs/21 discs) in the CT scan. Pains encountered during discography were radiating pain in 12 discs and back pain in 24 discs. CT-discography was especially helpful in 10 patients with multilevel involvement of the lumbar disc diseases to evaluate the exact location of diseased disc(s) that provoked the pain. CT-discography is a highly accurate method in diagnosis of the herniated lumbar intervertebral discs and is very useful in determining the precise location related to the development of pain in such cases.

  20. Diagnostic accuracy of non-invasive 64-slice CT coronary angiography in patients with stable angina pectoris

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    Pugliese, Francesca; Krestin, Gabriel P. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Mollet, Nico R.A.; deFeyter, Pim J. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus Medical Center, Department of Cardiology, Rotterdam (Netherlands); Runza, Giuseppe [University of Palermo, Department of Radiology, Palermo (Italy); Azienda Ospedaliera di Parma, Department of Radiology, Parma (Italy); Mieghem, Carlos van; Meijboom, Willem B.; Baks, Timo [Erasmus Medical Center, Department of Cardiology, Rotterdam (Netherlands); Malagutti, Patrizia [Erasmus Medical Center, Department of Cardiology, Rotterdam (Netherlands); University of Ferrara, Department of Cardiology, Ferrara (Italy); Cademartiri, Filippo [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Azienda Ospedaliera di Parma, Department of Radiology, Parma (Italy)

    2006-03-15

    Multislice computed tomography (CT) is an emerging technique for the non-invasive detection of coronary stenoses. While the diagnostic accuracy of 4-slice scanners was limited, 16-slice CT imagers showed promising results due to increased temporal and spatial resolution. These technical advances prompted us to evaluate the diagnostic performance of 64-slice CT coronary angiography in the detection of significant stenoses (defined as {>=} 50% luminal diameter reduction) versus invasive quantitative coronary angiography (QCA). Thirty-five patients with stable angina pectoris underwent CT coronary angiography performed with a 64-slice scanner (gantry rotation time 330 ms, individual detector width 0.6 mm) prior to conventional coronary angiography. Patients with heart rates >70 beats/min received 100 mg metoprolol orally. One hundred millilitres of contrast agent with an iodine concentration of 400 mgl/ml were injected at a rate of 5 ml/s into the antecubital vein. The CT scan was triggered with the bolus tracking technique. The sensitivity, specificity and the positive and negative predictive values of 64-slice CT were 99%, 96%, 78% and 99%, respectively, on a per-segment basis. The values obtained on a per-patient basis were 100%, 90%, 96% and 100%, respectively. When referral to catheterisation is questionable, CT coronary angiography may identify subjects with normal angiograms and consistently decrease the number of unnecessary invasive procedures. (orig.)

  1. Accuracy and feasibility of three different methods for software-based image fusion in whole-body PET and CT.

    Science.gov (United States)

    Putzer, Daniel; Henninger, Benjamin; Kovacs, Peter; Uprimny, Christian; Kendler, Dorota; Jaschke, Werner; Bale, Reto J

    2016-06-01

    Even as PET/CT provides valuable diagnostic information in a great number of clinical indications, availability of hybrid PET/CT scanners is mainly limited to clinical centers. A software-based image fusion would facilitate combined image reading of CT and PET data sets if hardware image fusion is not available. To analyze the relevance of retrospective image fusion of separately acquired PET and CT data sets, we studied the accuracy, practicability and reproducibility of three different image registration techniques. We evaluated whole-body 18F-FDG-PET and CT data sets of 71 oncologic patients. Images were fused retrospectively using Stealth Station System, Treon (Medtronic Inc., Louisville, CO, USA) equipped with Cranial4 Software. External markers fixed to a vacuum mattress were used as reference for exact repositioning. Registration was repeated using internal anatomic landmarks and Automerge software, assessing accuracy for all three methods, measuring distances of liver representation in CT and PET with reference to a common coordinate system. On first measurement of image fusions with external markers, 53 were successful, 16 feasible and 2 not successful. Using anatomic landmarks, 42 were successful, 26 feasible and 3 not successful. Using Automerge Software only 13 were successful. The mean distance between center points in PET and CT was 7.69±4.96 mm on first, and 7.65±4.2 mm on second measurement. Results with external markers correlate very well and inaccuracies are significantly lower (Pfusion cost-effectively and significantly less time, posing an attractive alternative for PET/CT interpretation when a hybrid scanner is not available.

  2. Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Didier, Ryne A. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Vajtai, Petra L. [Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States); Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Hopkins, Katharine L. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States)

    2014-07-05

    Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated. This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDI{sub vol}). Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDI{sub vol}. Reduced CTDI{sub vol} was achieved primarily by reductions in effective tube current-time product (mAs{sub eff}) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDI{sub vol}, size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared. Between groups A and B, mean CTDI{sub vol} was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B. Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDI{sub vol} and SSDE by nearly half as compared to the hospital's traditional weight-based protocols. (orig.)

  3. Determination of dose delivery accuracy in CT examinations

    Directory of Open Access Journals (Sweden)

    Francis Hasford

    2015-10-01

    Full Text Available Volume computed tomography dose index (CTDIvol represents an average dose within a scan volume for a standardized CTDI phantom. It is a useful indicator of the dose to the standardized phantom for a specific examination protocol. Dose index (CTDIvol for head and body PMMA phantoms have been estimated in this study and comparison made with corresponding console displayed doses. The study was performed on 40 slice CT system, and measurements were done with 100 mm long pencil ion chamber connected to an electrometer. Doses were estimated using the AAPM Report 96 formalism. Estimated dose for head scan technique (120 kV, 150 mAs was 44.30 mGy, deviating from the console displayed dose by 4.49%. The body (pelvic scan technique of 120 kV and 100 mAs produced a dose estimate of 20.08 mGy in the body phantom, deviating by 3.05% from the console displayed dose. The estimated head and body phantom doses were compared to selected international dose reference levels and varying deviations were observed.

  4. Accuracy of cancellous bone volume fraction measured by micro-CT scanning

    DEFF Research Database (Denmark)

    Ding, Ming; Odgaard, A; Hvid, I

    1999-01-01

    Volume fraction, the single most important parameter in describing trabecular microstructure, can easily be calculated from three-dimensional reconstructions of micro-CT images. This study sought to quantify the accuracy of this measurement. One hundred and sixty human cancellous bone specimens...... which covered a large range of volume fraction (9.8-39.8%) were produced. The specimens were micro-CT scanned, and the volume fraction based on Archimedes' principle was determined as a reference. After scanning, all micro-CT data were segmented using individual thresholds determined by the scanner...

  5. Accuracy of iodine removal using dual-energy CT with or without a tin filter: an experimental phantom study.

    Science.gov (United States)

    Kawai, Tatsuya; Takeuchi, Mitsuru; Hara, Masaki; Ohashi, Kazuya; Suzuki, Hirochika; Yamada, Kiyotaka; Sugimura, Yuya; Shibamoto, Yuta

    2013-10-01

    The effects of a tin filter on virtual non-enhanced (VNE) images created by dual-energy CT have not been well evaluated. To compare the accuracy of VNE images between those with and without a tin filter. Two different types of columnar phantoms made of agarose gel were evaluated. Phantom A contained various concentrations of iodine (4.5-1590 HU at 120 kVp). Phantom B consisted of a central component (0, 10, 25, and 40 mgI/cm(3)) and a surrounding component (0, 50, 100, and 200 mgI/cm(3)) with variable iodine concentration. They were scanned by dual-source CT in conventional single-energy mode and dual-energy mode with and without a tin filter. CT values on each gel at the corresponding points were measured and the accuracy of iodine removal was evaluated. On VNE images, the CT number of the gel of Phantom A fell within the range between -15 and +15 HU under 626 and 881 HU at single-energy 120 kVp with and without a tin filter, respectively. With attenuation over these thresholds, iodine concentration of gels was underestimated with the tin filter but overestimated without it. For Phantom B, the mean CT numbers on VNE images in the central gel component surrounded by the gel with iodine concentrations of 0, 50, 100, and 200 mgI/cm(3) were in the range of -19-+6 HU and 21-100 HU with and without the tin filter, respectively. Both with and without a tin filter, iodine removal was accurate under a threshold of iodine concentration. Although a surrounding structure with higher attenuation decreased the accuracy, a tin filter improved the margin of error.

  6. Diagnostic accuracy of {sup 68}Ga-DOTANOC PET/CT imaging in pheochromocytoma

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Punit; Dhull, Varun Singh; Arora, Saurabh; Kumar, Rajeev; Malhotra, Arun; Kumar, Rakesh; Bal, Chandrasekhar [All India Institute of Medical Sciences, Department of Nuclear Medicine, Ansari Nagar, New Delhi (India); Gupta, Poonam; Ammini, Ariachery C. [All India Institute of Medical Sciences, Department of Endocrinology and Metabolism, New Delhi (India); Durgapal, Prashant [All India Institute of Medical Sciences, Department of Pathology, New Delhi (India); Chumber, Sunil [All India Institute of Medical Sciences, Department of Surgical Disciplines, New Delhi (India)

    2014-03-15

    The purpose of the present study was to evaluate the diagnostic accuracy of {sup 68}Ga-DOTANOC positron emission tomography (PET)/CT in patients with suspicion of pheochromocytoma. Data of 62 patients [age 34.3 ± 16.1 years, 14 with multiple endocrine neoplasia type 2 (MEN2)] with clinical/biochemical suspicion of pheochromocytoma and suspicious adrenal lesion on contrast CT (n = 70), who had undergone {sup 68}Ga-DOTANOC PET/CT, were retrospectively analyzed. PET/CT images were analyzed visually as well as semiquantitatively, with measurement of maximum standardized uptake value (SUV{sub max}), SUV{sub mean}, SUV{sub max}/SUV{sub liver}, and SUV{sub mean}/SUV{sub liver}. Results of PET/CT were compared with {sup 131}I-metaiodobenzylguanidine (MIBG) imaging, which was available in 40 patients (45 lesions). Histopathology and/or imaging/clinical/biochemical follow-up (minimum 6 months) was used as reference standard. The sensitivity, specificity, and accuracy of {sup 68}Ga-DOTANOC PET/CT was 90.4, 85, and 88.7 %, respectively, on patient-based analysis and 92, 85, and 90 %, respectively, on lesion-based analysis. {sup 68}Ga-DOTANOC PET/CT showed 100 % accuracy in patients with MEN2 syndrome and malignant pheochromocytoma. On direct comparison, lesion-based accuracy of {sup 68}Ga-DOTANOC PET/CT for pheochromocytoma was significantly higher than {sup 131}I-MIBG imaging (91.1 vs 66.6 %, p = 0.035). SUV{sub max} was higher for pheochromocytomas than other adrenal lesions (p = 0.005), MEN2-associated vs sporadic pheochromocytoma (p = 0.012), but no difference was seen between benign vs malignant pheochromocytoma (p = 0.269). {sup 68}Ga-DOTANOC PET/CT shows high diagnostic accuracy in patients with suspicion of pheochromocytoma and is superior to {sup 131}I-MIBG imaging for this purpose. Best results of {sup 68}Ga-DOTANOC PET/CT are seen in patients with MEN2-associated and malignant pheochromocytoma. (orig.)

  7. High-resolution CT of transplanted teeth: imaging technique and measurement accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Gahleitner, Andre [Medical University of Vienna, Department of Radiology/Osteology and MR, Vienna (Austria); Medical University Vienna, Department of Radiology, Vienna (Austria); Kuchler, Ulrike; Heschl, Janina; Watzek, Georg [Medical University of Vienna, Department of Oral Surgery, Vienna (Austria); Homolka, Peter [Medical University of Vienna, Center for Biomedical Engineering and Physics, Vienna (Austria); Imhof, Herwig [Medical University of Vienna, Department of Radiology/Osteology and MR, Vienna (Austria)

    2008-12-15

    The aim of this study was to determine the accuracy of crown diameter measurements by dental CT as a tool for preoperative diagnosis before tooth transplantations. Fifty-eight patients underwent clinically indicated dental CT. The diameter of the crowns were measured by CT using a standard protocol (1.5-mm slice thickness, 1-mm table feed, 120 kV, 25-75 mA/s, 2-s scan time/slice, 512 matrix) and a standard dental software package. Postoperatively, the same distances were clinically measured using a sliding gauge. The degree of the deviation between CT measurements and clinical measurements was in the sub-millimeter range. According to the regression analysis, the correlation coefficient equals 0.98 and 0.97, indicating a strong relationship between the CT and the manual measurement of the crown diameter in the bucco-lingual and the mesio-distal direction. The mean deviation of CT measurements with regard to the bucco-lingual diameter of the crown was +0.08 mm (SD: {+-}0.38 mm). For the mesio-distal diameter, the mean deviation of CT measurements was -0.24 mm (SD: {+-}0.53 mm). These results demonstrate that dental CT promises to be a valuable tool for the evaluation of the potential and optimal size and site for tooth transplantations. (orig.)

  8. Diagnostic accuracy of static CT perfusion for the detection of myocardial ischemia

    DEFF Research Database (Denmark)

    Sørgaard, Mathias Holm; Kofoed, Klaus Fuglsang; Linde, Jesper James

    2016-01-01

    : Systematic literature review and meta-analysis of studies examining the diagnostic accuracy of static CTP imaging alone or combined with coronary CT angiography (CTA) in comparison to single photon emission computed tomography (SPECT), magnetic resonance perfusion (MRP), and/or invasive coronary angiography...

  9. The effect of breathing irregularities on quantitative accuracy of respiratory gated PET/CT

    NARCIS (Netherlands)

    Teo, Boon-Keng; Saboury, Babak; Munbodh, Reshma; Scheuermann, Joshua; Torigian, Drew A.; Zaidi, Habib; Alavi, Abass

    2012-01-01

    Purpose: 4D positron emission tomography and computed tomography (PET/CT) can be used to reduce motion artifacts by correlating the raw PET data with the respiratory cycle. The accuracy of each PET phase is dependent on the reproducibility and consistency of the breathing cycle during acquisition.

  10. Relationship between CT number and electron density, scatter angle and nuclear reaction for hadron-therapy treatment planning.

    Science.gov (United States)

    Matsufuji, N; Tomura, H; Futami, Y; Yamashita, H; Higashi, A; Minohara, S; Endo, M; Kanai, T

    1998-11-01

    The precise conversion of CT numbers to their electron densities is essential in treatment planning for hadron therapy. Although some conversion methods have already been proposed, it is hard to check the conversion accuracy during practical therapy. We have estimated the CT numbers of real tissues by a calculational method established by Mustafa and Jackson. The relationship between the CT numbers and the electron densities was investigated for various body tissues as well as some tissue-equivalent materials used for a conversion to check the accuracy of the current conversion methods. The result indicates a slight disagreement at the high-CT-number region. A precise estimation of the multiple scattering, nuclear reaction and range straggling of incident particles has been considered as being important to realize higher-level conformal therapy in the future. The relationship between these parameters and the CT numbers was also investigated for tissues and water. The result shows that it is sufficiently practical to replace these parameters for real tissues with those for water by adjusting the density.

  11. Diagnosis and quantitative estimation of pulmonary congestion or edema by pulmonary CT numbers

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Shiro; Nakamoto, Takaaki

    1987-12-01

    Pulmonary computed tomography (CT) was performed in 25 patients with left heart failure and 10 healthy persons to diagnose pulmonary congestion or edema associated with left heart failure. In an analysis of histogram for pulmonary CT numbers obtained from CT scans, CT numbers indicating pulmonary edema were defined as -650 to -750 H.U. This allowed pulmonary edema to be quantitatively estimated early when abnormal findings were not available on chest X-ray film or pulmonary circulation studies. Histograms for CT numbers could be displayed by colors on CT scans. (Namekawa, K.).

  12. Accuracy of trabecular bone microstructural measurement at planned dental implant sites using cone-beam CT datasets

    NARCIS (Netherlands)

    Ibrahim, N.; Parsa, A.; Hassan, B.; van der Stelt, P.; Aartman, I.H.A.; Wismeijer, D.

    2014-01-01

    Objective Cone-beam CT (CBCT) images are infrequently utilized for trabecular bone microstructural measurement due to the system's limited resolution. The aim of this study was to determine the accuracy of CBCT for measuring trabecular bone microstructure in comparison with micro CTCT). Materials

  13. Effects of CT image segmentation methods on the accuracy of long bone 3D reconstructions.

    Science.gov (United States)

    Rathnayaka, Kanchana; Sahama, Tony; Schuetz, Michael A; Schmutz, Beat

    2011-03-01

    An accurate and accessible image segmentation method is in high demand for generating 3D bone models from CT scan data, as such models are required in many areas of medical research. Even though numerous sophisticated segmentation methods have been published over the years, most of them are not readily available to the general research community. Therefore, this study aimed to quantify the accuracy of three popular image segmentation methods, two implementations of intensity thresholding and Canny edge detection, for generating 3D models of long bones. In order to reduce user dependent errors associated with visually selecting a threshold value, we present a new approach of selecting an appropriate threshold value based on the Canny filter. A mechanical contact scanner in conjunction with a microCT scanner was utilised to generate the reference models for validating the 3D bone models generated from CT data of five intact ovine hind limbs. When the overall accuracy of the bone model is considered, the three investigated segmentation methods generated comparable results with mean errors in the range of 0.18-0.24 mm. However, for the bone diaphysis, Canny edge detection and Canny filter based thresholding generated 3D models with a significantly higher accuracy compared to those generated through visually selected thresholds. This study demonstrates that 3D models with sub-voxel accuracy can be generated utilising relatively simple segmentation methods that are available to the general research community.

  14. Metastatic retropharyngeal lymph nodes: Comparison of CT and MR imaging for diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Hiroki, E-mail: hkato@gifu-u.ac.jp [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Kanematsu, Masayuki, E-mail: masa_gif@yahoo.co.jp [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); High-level Imaging Diagnosis Center, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194 (Japan); Watanabe, Haruo, E-mail: haruwow860@yahoo.co.jp [Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Mizuta, Keisuke, E-mail: kmizuta@gifu-u.ac.jp [Department of Otolaryngology, Gifu University School of Medicine, Gifu (Japan); Aoki, Mitsuhiro, E-mail: aoki@gifu-u.ac.jp [Department of Otolaryngology, Gifu University School of Medicine, Gifu (Japan)

    2014-07-15

    Purpose: The purpose of this study was to compare the diagnostic accuracies of CT and MR imaging for the detection of metastatic retropharyngeal lymph nodes (RLNs) in patients with nasopharyngeal and oropharyngeal squamous cell carcinoma (SCC). Materials and methods: The study included 38 patients (28 men and 10 women; mean age, 65 years; age range, 48–82 years) with nasopharyngeal (n = 15) and oropharyngeal (n = 23) SCC who underwent both contrast-enhanced CT and MR imaging before chemoradiotherapy. RLNs were classified as malignant or benign on the basis of the results of follow-up MR imaging. Two radiologists independently evaluated the images for diagnosing metastatic RLNs. Results: Among a total of 68 RLNs (minimum diameter, ≥4 mm) that were detected on gadolinium-enhanced fat-suppressed T1-weighted images, 30 (44%) were malignant and 38 (56%) were benign. The sensitivities of CT versus MRI were 60% versus 97% for observer 1 (p < 0.01) and 37% versus 90% for observer 2 (p < 0.01). The specificities of CT versus MRI were 92% versus 97% for observer 1 (p = 0.50) and 92% versus 100% for observer 2 (p = 0.25). The areas under the receiver operating characteristic curve (AUC) for CT versus MRI were 0.788 versus 0.996 for observer 1 (p < 0.01) and 0.693 versus 0.961 for observer 2 (p < 0.01). Conclusion: MR imaging was superior to CT for the detection of metastatic RLNs.

  15. Diagnostic accuracy and safety of CT-guided fine needle aspiration biopsy in cavitary pulmonary lesions

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Yi-Ping, E-mail: yipingzhuang2010@sina.com [Department of Radiology, Jiangsu Cancer Institute and Hospital, No. 42 Baiziting Road, Nanjing 210009, Jiangsu (China); Wang, Hai-Yan, E-mail: mycherishgirl@sohu.com [Department of Radiology, Jiangsu Cancer Institute and Hospital, No. 42 Baiziting Road, Nanjing 210009, Jiangsu (China); Zhang, Jin, E-mail: yari_zj@hotmail.com [Department of Radiology, Jiangsu Cancer Institute and Hospital, No. 42 Baiziting Road, Nanjing 210009, Jiangsu (China); Feng, Yong, E-mail: fengyong119@sohu.com [Department of Radiology, Jiangsu Cancer Institute and Hospital, No. 42 Baiziting Road, Nanjing 210009, Jiangsu (China); Zhang, Lei, E-mail: motozl163@163.com [Department of Radiology, Jiangsu Cancer Institute and Hospital, No. 42 Baiziting Road, Nanjing 210009, Jiangsu (China)

    2013-01-15

    Objective: CT-guided transthoracic biopsy is a well-established method in the cytologic or histologic diagnosis of pulmonary lesions. The knowledge of its diagnostic performance and complications for cavitary pulmonary lesions is limited. The purpose of this study was to determine the diagnostic accuracy and safety of CT-guided fine needle aspiration biopsy (FNAB) in cavitary pulmonary lesions. Materials and methods: 102 consecutive patients with pulmonary cavitary lesions received CT-guided FNAB with use of an 18-gauge (n = 35) or 20-gauge (n = 67) Chiba for histology diagnosis. The sensitivity, specificity, and diagnostic accuracy of FNAB were calculated as compared with the final diagnosis. Complications associated with FNAB were observed. The diagnostic accuracy and complications were compared between patients with different lesion sizes and different cavity wall thickness. Results: The overall sensitivity, specificity, and accuracy of FNAB were 96.3%, 98.0%, and 96.1%, respectively. The sensitivity, specificity, and diagnosis accuracy in different lesion size (<2 cm vs ≥2 cm), or different cavity wall thickness (<5 mm vs ≥5 mm) were not different (P > 0.05; 0.235). More nondiagnostic sample was found in wall thickness <5 mm lesions (P = 0.017). Associated complications included pneumothorax in 9 (8.8%) patients and alveolar hemorrhage in 14 patients (13.7%) and hemoptysis in 1 patient (1%). No different rate of complications was found with regard to lesion size, wall thickness, length of the needle path and needle size (P > 0.05). Conclusion: CT-guided FNAB can be effectively ad safely used for patients with pulmonary cavitary lesions.

  16. Factors Affecting Dimensional Accuracy of 3-D Printed Anatomical Structures Derived from CT Data.

    Science.gov (United States)

    Ogden, Kent M; Aslan, Can; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Soman, Pranav

    2015-12-01

    Additive manufacturing and bio-printing, with the potential for direct fabrication of complex patient-specific anatomies derived from medical scan data, are having an ever-increasing impact on the practice of medicine. Anatomic structures are typically derived from CT or MRI scans, and there are multiple steps in the model derivation process that influence the geometric accuracy of the printed constructs. In this work, we compare the dimensional accuracy of 3-D printed constructs of an L1 vertebra derived from CT data for an ex vivo cadaver T-L spine with the original vertebra. Processing of segmented structures using binary median filters and various surface extraction algorithms is evaluated for the effect on model dimensions. We investigate the effects of changing CT reconstruction kernels by scanning simple geometric objects and measuring the impact on the derived model dimensions. We also investigate if there are significant differences between physical and virtual model measurements. The 3-D models were printed using a commercial 3-D printer, the Replicator 2 (MakerBot, Brooklyn, NY) using polylactic acid (PLA) filament. We found that changing parameters during the scan reconstruction, segmentation, filtering, and surface extraction steps will have an effect on the dimensions of the final model. These effects need to be quantified for specific situations that rely on the accuracy of 3-D printed models used in medicine or tissue engineering applications.

  17. Spatial Component Position in Total Hip Arthroplasty. Accuracy and repeatability with a new CT method

    Energy Technology Data Exchange (ETDEWEB)

    Olivecrona, H. [Soedersjukhuset, Stockholm (Sweden). Dept. of Hand Surgery; Weidenhielm, L. [Karolinska Hospital, Stockholm (Sweden). Dept. of Orthopedics; Olivecrona, L. [Karolinska Hospital, Stockholm (Sweden). Dept. of Radiology; Noz, M.E. [New York Univ. School of Medicine, NY (United States). Dept. of Radiology; Maguire, G.Q. [Royal Inst. of Tech., Kista (Sweden). Inst. for Microelectronics and Information Technology; Zeleznik, M. P. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Radiation Oncology; Svensson, L. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Mathematics; Jonson, T. [Eskadern Foeretagsutveckling AB, Goeteborg (Sweden)

    2003-03-01

    Purpose: 3D detection of centerpoints of prosthetic cup and head after total hip arthroplasty (THA) using CT. Material and Methods: Two CT examinations, 10 min apart, were obtained from each of 10 patients after THA. Two independent examiners placed landmarks in images of the prosthetic cup and head. All landmarking was repeated after 1 week. Centerpoints were calculated and compared. Results: Within volumes, all measurements of centerpoints of cup and head fell, with a 95% confidence, within one CT-voxel of any other measurement of the same object. Across two volumes, the mean error of distance between center of cup and prosthetic head was 1.4 mm (SD 0.73). Intra- and interobserver 95% accuracy limit was below 2 mm within and below 3 mm across volumes. No difference between intra- and interobserver measurements occurred. A formula for converting finite sets of point landmarks in the radiolucent tread of the cup to a centerpoint was stable. The percent difference of the landmark distances from a calculated spherical surface was within one CT-voxel. This data was normally distributed and not dependent on observer or trial. Conclusion: The true 3D position of the centers of cup and prosthetic head can be detected using CT. Spatial relationship between the components can be analyzed visually and numerically.

  18. Quantification of the accuracy of MRI generated 3D models of long bones compared to CT generated 3D models.

    Science.gov (United States)

    Rathnayaka, Kanchana; Momot, Konstantin I; Noser, Hansrudi; Volp, Andrew; Schuetz, Michael A; Sahama, Tony; Schmutz, Beat

    2012-04-01

    Orthopaedic fracture fixation implants are increasingly being designed using accurate 3D models of long bones based on computer tomography (CT). Unlike CT, magnetic resonance imaging (MRI) does not involve ionising radiation and is therefore a desirable alternative to CT. This study aims to quantify the accuracy of MRI-based 3D models compared to CT-based 3D models of long bones. The femora of five intact cadaver ovine limbs were scanned using a 1.5 T MRI and a CT scanner. Image segmentation of CT and MRI data was performed using a multi-threshold segmentation method. Reference models were generated by digitising the bone surfaces free of soft tissue with a mechanical contact scanner. The MRI- and CT-derived models were validated against the reference models. The results demonstrated that the CT-based models contained an average error of 0.15 mm while the MRI-based models contained an average error of 0.23 mm. Statistical validation shows that there are no significant differences between 3D models based on CT and MRI data. These results indicate that the geometric accuracy of MRI based 3D models was comparable to that of CT-based models and therefore MRI is a potential alternative to CT for generation of 3D models with high geometric accuracy.

  19. High accuracy semidefinite programming bounds for kissing numbers

    NARCIS (Netherlands)

    Mittelmann, H.D.; Vallentin, F.

    2009-01-01

    The kissing number in n-dimensional Euclidean space is the maximal number of non-overlapping unit spheres which simultaneously can touch a central unit sphere. Bachoc and Vallentin developed a method to find upper bounds for the kissing number based on semidefinite programming. This paper is a repor

  20. High accuracy semidefinite programming bounds for kissing numbers

    NARCIS (Netherlands)

    H.D. Mittelmann; F. Vallentin (Frank)

    2010-01-01

    htmlabstractThe kissing number in n-dimensional Euclidean space is the maximal number of non-overlapping unit spheres which simultaneously can touch a central unit sphere. Bachoc and Vallentin developed a method to find upper bounds for the kissing number based on semidefinite programming. This

  1. High accuracy semidefinite programming bounds for kissing numbers

    NARCIS (Netherlands)

    H.D. Mittelmann; F. Vallentin (Frank)

    2009-01-01

    htmlabstractThe kissing number in n-dimensional Euclidean space is the maximal number of non-overlapping unit spheres which simultaneously can touch a central unit sphere. Bachoc and Vallentin developed a method to find upper bounds for the kissing number based on semidefinite programming. This

  2. Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off

    Energy Technology Data Exchange (ETDEWEB)

    Luboldt, Wolfgang [Multiorgan Screening Foundation, Frankfurt (Germany); University Hospital Frankfurt, Department of Radiology, Frankfurt am Main (Germany); University Hospital Dresden, Clinic and Policlinic of Nuclear Medicine, Dresden (Germany); Volker, Teresa; Zoephel, Klaus; Kotzerke, Joerg [University Hospital Dresden, Clinic and Policlinic of Nuclear Medicine, Dresden (Germany); Wiedemann, Baerbel [University Hospital Dresden, Institute of Medical Informatics and Biometrics, Dresden (Germany); Wehrmann, Ursula [University Hospital Dresden, Clinic and Policlinic of Surgery, Dresden (Germany); Koch, Arne; Abolmaali, Nasreddin [University Hospital Dresden, Oncoray, Dresden (Germany); Toussaint, Todd; Luboldt, Hans-Joachim [Multiorgan Screening Foundation, Frankfurt (Germany); Middendorp, Markus; Gruenwald, Frank [University Hospital Frankfurt, Department of Nuclear Medicine, Frankfurt (Germany); Aust, Daniela [University Hospital Dresden, Department of Pathology, Dresden (Germany); Vogl, Thomas J. [University Hospital Frankfurt, Department of Radiology, Frankfurt am Main (Germany)

    2010-09-15

    To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas {>=}10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off. 84 patients, who underwent PET/CT and colonoscopy (n=79)/sigmoidoscopy (n=5) for (79 x 6+5 x 2)=484 colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs. Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n=23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n=10) the SUV{sub max} was {>=}5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV{sub max}. FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV{sub max}{>=} 5 improves the accuracy. (orig.)

  3. Motion correction for improving the accuracy of dual-energy myocardial perfusion CT imaging

    Science.gov (United States)

    Pack, Jed D.; Yin, Zhye; Xiong, Guanglei; Mittal, Priya; Dunham, Simon; Elmore, Kimberly; Edic, Peter M.; Min, James K.

    2016-03-01

    Coronary Artery Disease (CAD) is the leading cause of death globally [1]. Modern cardiac computed tomography angiography (CCTA) is highly effective at identifying and assessing coronary blockages associated with CAD. The diagnostic value of this anatomical information can be substantially increased in combination with a non-invasive, low-dose, correlative, quantitative measure of blood supply to the myocardium. While CT perfusion has shown promise of providing such indications of ischemia, artifacts due to motion, beam hardening, and other factors confound clinical findings and can limit quantitative accuracy. In this paper, we investigate the impact of applying a novel motion correction algorithm to correct for motion in the myocardium. This motion compensation algorithm (originally designed to correct for the motion of the coronary arteries in order to improve CCTA images) has been shown to provide substantial improvements in both overall image quality and diagnostic accuracy of CCTA. We have adapted this technique for application beyond the coronary arteries and present an assessment of its impact on image quality and quantitative accuracy within the context of dual-energy CT perfusion imaging. We conclude that motion correction is a promising technique that can help foster the routine clinical use of dual-energy CT perfusion. When combined, the anatomical information of CCTA and the hemodynamic information from dual-energy CT perfusion should facilitate better clinical decisions about which patients would benefit from treatments such as stent placement, drug therapy, or surgery and help other patients avoid the risks and costs associated with unnecessary, invasive, diagnostic coronary angiography procedures.

  4. Accuracy of hepatocellular carcinoma detection on multidetector CT in a transplant liver population with explant liver correlation

    Energy Technology Data Exchange (ETDEWEB)

    Addley, H.C., E-mail: helenclareaddley@hotmail.co.u [Department of Radiology, Addenbrooke' s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); Griffin, N.; Shaw, A.S.; Mannelli, L. [Department of Radiology, Addenbrooke' s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); Parker, R.A. [Department of Medical Statistics, Addenbrooke' s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); Aitken, S.; Wood, H. [Department of Radiology, Addenbrooke' s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); Davies, S. [Department of Histopathology, Addenbrooke' s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); Alexander, G.J. [Department of Hepatology, Addenbrooke' s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); Lomas, D.J. [Department of Radiology, Addenbrooke' s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom)

    2011-04-15

    Aim: To evaluate the diagnostic accuracy of multidetector computed tomography (MDCT) for hepatocellular carcinoma (HCC) in cirrhotic patients undergoing liver transplantation. Secondary aims were to examine the effect of radiologist experience and lesion size on diagnostic accuracy. Materials and methods: Thirty-nine patients (72% male with a mean age of 56.5 years) underwent liver transplantation following preoperative triple-phase MDCT examination of the liver. MDCT examinations were retrospectively independently reviewed by three radiologists for the presence and location of suspected HCCs, with the diagnostic confidence recorded using a five-point confidence scale. MDCT examinations were compared with explant specimens for histopathological correlation. Results: Histopathological results demonstrated 46 HCCs in 29 of the 39 patients. Analysis demonstrated a sensitivity of 65-75% and specificity of 47-88% for detection of HCC lesions. The sensitivity dropped to 48-57% for lesions of size {<=}20 mm. As the diagnostic confidence increased, there was a further decrease in the sensitivity (4-26%). The radiologist with the greatest number of years experience was found to have a significantly higher accuracy of detection of HCC lesions compared with the least experienced radiologist. Conclusion: Larger lesion size of HCC and greater number of years experience of the radiologist resulted in significantly higher accuracy of HCC lesion detection. The overall sensitivity and specificity results for MDCT detection of HCC are comparable to previous helical CT imaging.

  5. A comparative study of the diagnostic accuracy on Waters view with CT scan in detecting midface fractures

    OpenAIRE

    Panjnoush M.; Shirani Gh.; Jozghanbari P.

    2006-01-01

    Background and Aim: In recent years, CT scan has become available as an alternative to conventional radiography. To date, the utility of Waters view in detecting midface fractures has been rarely evaluated. The aim of this study was to compare the diagnostic accuracy and reliability of Waters radiography with CT scan in detecting midface fractures. Materials and Methods: In this tests evaluation study, waters view and CT scan were performed for 42 patients with midface fracture admitted to ma...

  6. Diagnostic accuracy at several reduced radiation dose levels for CT imaging in the diagnosis of appendicitis

    Science.gov (United States)

    Zhang, Di; Khatonabadi, Maryam; Kim, Hyun; Jude, Matilda; Zaragoza, Edward; Lee, Margaret; Patel, Maitraya; Poon, Cheryce; Douek, Michael; Andrews-Tang, Denise; Doepke, Laura; McNitt-Gray, Shawn; Cagnon, Chris; DeMarco, John; McNitt-Gray, Michael

    2012-03-01

    Purpose: While several studies have investigated the tradeoffs between radiation dose and image quality (noise) in CT imaging, the purpose of this study was to take this analysis a step further by investigating the tradeoffs between patient radiation dose (including organ dose) and diagnostic accuracy in diagnosis of appendicitis using CT. Methods: This study was IRB approved and utilized data from 20 patients who underwent clinical CT exams for indications of appendicitis. Medical record review established true diagnosis of appendicitis, with 10 positives and 10 negatives. A validated software tool used raw projection data from each scan to create simulated images at lower dose levels (70%, 50%, 30%, 20% of original). An observer study was performed with 6 radiologists reviewing each case at each dose level in random order over several sessions. Readers assessed image quality and provided confidence in their diagnosis of appendicitis, each on a 5 point scale. Liver doses at each case and each dose level were estimated using Monte Carlo simulation based methods. Results: Overall diagnostic accuracy varies across dose levels: 92%, 93%, 91%, 90% and 90% across the 100%, 70%, 50%, 30% and 20% dose levels respectively. And it is 93%, 95%, 88%, 90% and 90% across the 13.5-22mGy, 9.6-13.5mGy, 6.4-9.6mGy, 4-6.4mGy, and 2-4mGy liver dose ranges respectively. Only 4 out of 600 observations were rated "unacceptable" for image quality. Conclusion: The results from this pilot study indicate that the diagnostic accuracy does not change dramatically even at significantly reduced radiation dose.

  7. Accuracy of CT-guided percutaneous core needle biopsy for assessment of pediatric musculoskeletal lesions

    Energy Technology Data Exchange (ETDEWEB)

    Hryhorczuk, Anastasia L. [University of Michigan, Department of Radiology, C. S. Mott Children' s Hospital, Ann Arbor, MI (United States); Harvard University School of Medicine, Department of Radiology, Boston Children' s Hospital, Boston, MA (United States); Strouse, Peter J. [University of Michigan, Department of Radiology, C. S. Mott Children' s Hospital, Ann Arbor, MI (United States); Biermann, J.S. [University of Michigan, Department of Orthopaedic Surgery, Ann Arbor, MI (United States)

    2011-07-15

    CT-guided percutaneous core needle biopsy has been shown in adults to be an effective diagnostic tool for a large number of musculoskeletal malignancies. To characterize our experience with CT-guided percutaneous core needle biopsy of pediatric bone lesions and determine its utility in diagnosing pediatric osseous lesions, in a population where such lesions are commonly benign. From 2000 to 2009, 61 children underwent 63 CT-guided percutaneous biopsies. Radiological, pathological and clinical records were reviewed. Fourteen biopsies (22%) were performed on malignant lesions, while 49 biopsies (78%) were performed on benign lesions. Forty-nine of the 63 biopsies (78%) were adequate; these children underwent no further tissue sampling. Fourteen of the 63 biopsies (22%) were inadequate or non-conclusive. Of these patients, 12 underwent open biopsy. Retrospective analysis of percutaneous biopsies in these patients demonstrates that 9/12 provided clinically relevant information, and 4/12 patients received final diagnoses that confirmed initial core biopsy findings. No malignancies were diagnosed as benign on percutaneous biopsy. Overall, percutaneous core needle biopsy provided accurate diagnostic information in 84% (53/63) of biopsies. Our results demonstrate that CT-guided percutaneous biopsy is safe and beneficial in children. This study supports the use of CT-guided percutaneous core needle biopsy for primary diagnosis of pediatric bone lesions. (orig.)

  8. Diagnostic accuracy of {sup 11}C-choline PET/CT in comparison with CT and/or MRI in patients with hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Lopci, Egesta [Nuclear Medicine Department, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Torzilli, Guido; Donadon, Matteo; Palmisano, Angela [Hepatobiliary Surgery, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Poretti, Dario; Lanza, Ezio; Pedicini, Vittorio [Radiology Unit, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Neto, Lauro J.S. de; Sabongi, Juliano Guerra [Medicina Nuclear, Centro Medico Imagem, Sorocaba (Brazil); Rimassa, Lorenza; Personeni, Nicola [Medical Oncology and Hematology Unit, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Ceriani, Roberto [Hepatology Unit, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Comito, Tiziana; Scorsetti, Marta [Radiosurgery and Radiotherapy, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Chiti, Arturo [Nuclear Medicine Department, Humanitas Clinical and Research Center, Rozzano, MI (Italy); Humanitas University, Chair of Diagnostic Imaging, Rozzano, MI (Italy)

    2015-08-15

    In recent decades, the use of radiopharmaceuticals in the assessment of hepatocellular carcinoma (HCC) has become established, and new findings indicate that radiolabelled choline has considerable potential in this setting. Therefore, in this study we aimed to assess the diagnostic role of {sup 11}C-choline positron emission tomography (PET)/CT, compared with conventional imaging with CT/MRI, in patients with HCC. The study population comprised 45 patients (male to female ratio = 37:8, median age 70.5 years) referred to our institution owing to HCC: 27 at initial diagnosis and 18 for restaging after recurrence. In all cases we performed whole-body {sup 11}C-choline PET/CT and compared its findings with contrast-enhanced CT (n = 35) or MRI (n = 29) or both (n = 15) for a total of 50 paired scans. The reference standard was either histological proof (21 patients) or a multidisciplinary consensus. Diagnostic accuracy was then determined in a scan-based (SBA) and a lesion-based analysis (LBA). On SBA the sensitivity and specificity for PET were 88 and 90 %, respectively, whereas for CT/MRI they were 90 and 73 %, respectively (p > 0.05). On LBA the overall sensitivity and specificity were 78 and 86 %, respectively, for PET vs 65 and 55 % for CT/MRI. Overall we investigated 168 disease sites, of which 100 were in the liver and 68 were extrahepatic. When considering only liver lesions, {sup 11}C-choline PET and CT/MRI showed an accuracy of 66 and 85 %, respectively, while for extrahepatic lesions PET showed an accuracy of 99 %, while the accuracy of CT/MRI was 32 %. In both cases, there was a statistically significant difference in accuracy between the two modalities (p < 0.01). Combination of the PET results with those of CT/MRI resulted in the highest diagnostic accuracy in both analyses, at 92 % for SBA and 96 % for LBA. In 11 patients (24 %) the PET findings modified the therapeutic strategy, the modification proving appropriate in 10 of them. {sup 11}C-Choline PET

  9. Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

    Science.gov (United States)

    Wu, T.-H.; Liang, C.-H.; Wu, J.-K.; Lien, C.-Y.; Yang, B.-H.; Huang, Y.-H.; Lee, J. J. S.

    2009-07-01

    Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of 18F-fluorodeoxyglucose (18F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT may have a

  10. Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, T-H [Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, No. 110, Sec.1, Jianguo N.Rd, Taichung City 40201, Taiwan (China); Liang, C-H [Agfa Healthcare Systems Taiwan Co., Ltd., 6F, 237 Sung Chiang Road, Taipei, 104 Taiwan (China); Wu, J-K [Division of Radiation Oncology, Department of Oncology, and Cancer Research Center, National Taiwan University Hospital, No.7 Chung San South Road, Taipei, 104 Taiwan (China); Lien, C-Y [Institute of Biomedical Engineering, National Yang Ming University, No. 155, Sec.2, Linong Street, Taipei, 112 Taiwan (China); Yang, B-H; Lee, J J S [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, No. 155, Sec.2, Linong Street, Taipei, 112 Taiwan (China); Huang, Y-H [Department of Medical Imaing and Radiological Sciences, I-Shou University, No. 8, Yida Rd., Yanchao Township, Kaohsiung County 82445, Taiwan (China)], E-mail: jslee@ym.edu.tw

    2009-07-15

    Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT

  11. High Dose MicroCT Does Not Contribute Toward Improved MicroPET/CT Image Quantitative Accuracy and Can Limit Longitudinal Scanning of Small Animals

    Directory of Open Access Journals (Sweden)

    Wendy A. McDougald

    2017-10-01

    Full Text Available Obtaining accurate quantitative measurements in preclinical Positron Emission Tomography/Computed Tomography (PET/CT imaging is of paramount importance in biomedical research and helps supporting efficient translation of preclinical results to the clinic. The purpose of this study was two-fold: (1 to investigate the effects of different CT acquisition protocols on PET/CT image quality and data quantification; and (2 to evaluate the absorbed dose associated with varying CT parameters.Methods: An air/water quality control CT phantom, tissue equivalent material phantom, an in-house 3D printed phantom and an image quality PET/CT phantom were imaged using a Mediso nanoPET/CT scanner. Collected data was analyzed using PMOD software, VivoQuant software and National Electric Manufactures Association (NEMA software implemented by Mediso. Measured Hounsfield Unit (HU in collected CT images were compared to the known HU values and image noise was quantified. PET recovery coefficients (RC, uniformity and quantitative bias were also measured.Results: Only less than 2 and 1% of CT acquisition protocols yielded water HU values < −80 and air HU values < −840, respectively. Four out of 11 CT protocols resulted in more than 100 mGy absorbed dose. Different CT protocols did not impact PET uniformity and RC, and resulted in <4% overall bias relative to expected radioactive concentration.Conclusion: Preclinical CT protocols with increased exposure times can result in high absorbed doses to the small animals. These should be avoided, as they do not contributed toward improved microPET/CT image quantitative accuracy and could limit longitudinal scanning of small animals.

  12. Accuracy of Non-Enhanced CT in Detecting Early Ischemic Edema Using Frequency Selective Non-Linear Blending.

    Directory of Open Access Journals (Sweden)

    Georg Bier

    Full Text Available Ischemic brain edema is subtle and hard to detect by computed tomography within the first hours of stroke onset. We hypothesize that non-enhanced CT (NECT post-processing with frequency-selective non-linear blending ("best contrast"/BC increases its accuracy in detecting edema and irreversible tissue damage (infarction.We retrospectively analyzed the NECT scans of 76 consecutive patients with ischemic stroke (exclusively middle cerebral artery territory-MCA before and after post-processing with BC both at baseline before reperfusion therapy and at follow-up (5.73±12.74 days after stroke onset using the Alberta Stroke Program Early CT Score (ASPECTS. We assessed the differences in ASPECTS between unprocessed and post-processed images and calculated sensitivity, specificity, and predictive values of baseline NECT using follow-up CT serving as reference standard for brain infarction.NECT detected brain tissue hypoattenuation in 35 of 76 patients (46.1%. This number increased to 71 patients (93.4% after post-processing with BC. Follow-up NECT confirmed brain infarctions in 65 patients (85.5%; p = 0.012. Post-processing increased the sensitivity of NECT for brain infarction from 35/65 (54% to 65/65 (100%, decreased its specificity from 11/11 (100% to 7/11 (64%, its positive predictive value (PPV from 35/35 (100% to 65/69 (94% and increased its accuracy 46/76 (61% to 72/76 (95%.This post-hoc analysis suggests that post-processing of NECT with BC may increase its sensitivity for ischemic brain damage significantly.

  13. Accuracy of 18F-FDG PET/CT for lymph node staging in non-small-cell lung cancers

    Institute of Scientific and Technical Information of China (English)

    LIU Bao-jun; DONG Jing-cheng; XU Chang-qing; ZUO Chuan-tao; LE Jing-jing; GUAN Yi-hui; ZHAO Jun; WU Jin-feng; DUAN Xiao-hong; CAO Yu-xue

    2009-01-01

    Background This retrospective study evaluated the diagnostic accuracy of 2-(F18)-fluoro-2-deoxy-D-glucose-positron emission tomography(18F-FDG-PET)/COmputed tomography(PET/CT)in the preoperative diagnosis of metastatic mediastinal and hilar lymph node in patients with non-small-cell lung cancer(NSCLC).Methods A total of 39 patients received preoperative 18F-FDG PET/CT and the postoperative biopsy.We compared preoperative PET/CT scan results with corresponding intraoperative histopathalogic findings in 39 NSCLC patients.The sensitivity,specificity,accuracy,positive and negative predictive value of 18F-FDG PET/CT were assessed.Results Histopathologic examination confirmed metastasis in 57 out of the 208 excised lymph nodes;23 of the 57 nodes were mediastinal and hilar lymph nodes.The sensitivity,specificity,accuracy,positive predictive value and negative predictive value of PET/CT in the preoperative diagnosis of mediastinal lymph node metastasis in NSCLC patients were 65%,96.8%,92%,78.5%and 90%,respectively.Conclusions PET/CT scan showed good accuracy in the preoperative diagnosis of mediastinal and hilar lymph node metastasis in the patients with NSCLC.We recommend that PET/CT scanning be used as a first-line evaluation tool for tumor diagnosis,therapy evaluation and follow-up.

  14. THE DIAGNOSTIC ACCURACY OF CHEST CT IN THE DETECTION OF TUMOR AND NODAL STATUS IN NON SMALL CELL LUNG CARCINOMA

    Directory of Open Access Journals (Sweden)

    Aziza Icksan

    2003-12-01

    Full Text Available At this time there is an increasing demand for an accurate preoperative staging in non small cell lung cancer. Chest Computed Tomography (CT is one of the imaging modality of choice used for this purpose. This study evaluated the accuracy of the chest CT to determine the status of the tumor and nodules in non small cell lung cancer. During the years 1998 and 1999, a descriptive prospective study of 32 patients undergoing a contrast enhanced chest CT examination for non small cell lung cancer, stage I-IIIA, was conducted. Lobectomy, lymph nodes dissection and postoperative histo-pathological examination were done. CT findings were as follows: a sensitivity of 100%, a specificity of 25% and an accuracy of 60% in the detection of the nodule stage were found. In 17 patients with adeno-carcinoma, the sensitivity, the specificity and the accuracy were 86.6%, 100% and 88.2% respectively. The diagnosis of all patients was confirmed histo-pathologically. Six patients with T2 and 26 patients with T3 were detected by chest CT; the accuracy of the tumor status was 93.7%, confirmed by surgical and histo-pathological examinations. It was concluded that the CT played an important role in determining the clinical stage of non small cell lung cancer. The specificity and accuracy were higher in adeno-carcinoma as compared with squamous cell carcinoma in detecting the nodal status.

  15. Dependence of quantitative accuracy of CT perfusion imaging on system parameters

    Science.gov (United States)

    Li, Ke; Chen, Guang-Hong

    2017-03-01

    Deconvolution is a popular method to calculate parametric perfusion parameters from four dimensional CT perfusion (CTP) source images. During the deconvolution process, the four dimensional space is squeezed into three-dimensional space by removing the temporal dimension, and a prior knowledge is often used to suppress noise associated with the process. These additional complexities confound the understanding about deconvolution-based CTP imaging system and how its quantitative accuracy depends on parameters and sub-operations involved in the image formation process. Meanwhile, there has been a strong clinical need in answering this question, as physicians often rely heavily on the quantitative values of perfusion parameters to make diagnostic decisions, particularly during an emergent clinical situation (e.g. diagnosis of acute ischemic stroke). The purpose of this work was to develop a theoretical framework that quantitatively relates the quantification accuracy of parametric perfusion parameters with CTP acquisition and post-processing parameters. This goal was achieved with the help of a cascaded systems analysis for deconvolution-based CTP imaging systems. Based on the cascaded systems analysis, the quantitative relationship between regularization strength, source image noise, arterial input function, and the quantification accuracy of perfusion parameters was established. The theory could potentially be used to guide developments of CTP imaging technology for better quantification accuracy and lower radiation dose.

  16. Influence of age and position on the CT number of adipose tissues in pigs.

    Science.gov (United States)

    McEvoy, Fintan J; Madsen, Mads T; Svalastoga, Eiliv L

    2008-10-01

    The location of adipose tissue depots is important in determining their significance. Research into the physical and chemical differences between these depots is therefore of interest. Using image analysis, this paper examines the influence of location on the linear attenuation coefficient of adipose tissue for X-rays, in computed tomography (as indicated by CT number) at three time points. Nine pigs were CT scanned on three separate occasions approximately 1 month apart. The mean CT number was -78, -100, and -104 for visceral adipose tissue (VAT) from the first to the final scan, respectively. The corresponding CT numbers for subcutaneous adipose tissue (SAT) were -80, -101, and -106. There was a significant difference between the CT numbers at each location at each scan (P values from 0.025 to <0.001) and between the CT numbers for each location at different times (P < 0.05). In a separate analysis of the final scan session, the mean CT number of adipose tissue at increasing distances from a mathematically defined center of the animal was determined. Regression analysis showed that the CT number of adipose tissue decreases with increasing distance from the animal's center (y = -102.7 - 0.04 x, P < 0.001, where y is the predicted CT number for adipose tissue, from the animal center (x = 0) to the skin (x = 100)). It can thus be expected that the overall mean CT number for adipose tissue can be used as an indicator of the relative quantities of adipose tissue at each location if the mean for each is known.

  17. Improving Intensity-Based Lung CT Registration Accuracy Utilizing Vascular Information

    Directory of Open Access Journals (Sweden)

    Kunlin Cao

    2012-01-01

    Full Text Available Accurate pulmonary image registration is a challenging problem when the lungs have a deformation with large distance. In this work, we present a nonrigid volumetric registration algorithm to track lung motion between a pair of intrasubject CT images acquired at different inflation levels and introduce a new vesselness similarity cost that improves intensity-only registration. Volumetric CT datasets from six human subjects were used in this study. The performance of four intensity-only registration algorithms was compared with and without adding the vesselness similarity cost function. Matching accuracy was evaluated using landmarks, vessel tree, and fissure planes. The Jacobian determinant of the transformation was used to reveal the deformation pattern of local parenchymal tissue. The average matching error for intensity-only registration methods was on the order of 1 mm at landmarks and 1.5 mm on fissure planes. After adding the vesselness preserving cost function, the landmark and fissure positioning errors decreased approximately by 25% and 30%, respectively. The vesselness cost function effectively helped improve the registration accuracy in regions near thoracic cage and near the diaphragm for all the intensity-only registration algorithms tested and also helped produce more consistent and more reliable patterns of regional tissue deformation.

  18. Monte Carlo calculated CT numbers for improved heavy ion treatment planning

    Directory of Open Access Journals (Sweden)

    Qamhiyeh Sima

    2014-03-01

    Full Text Available Better knowledge of CT number values and their uncertainties can be applied to improve heavy ion treatment planning. We developed a novel method to calculate CT numbers for a computed tomography (CT scanner using the Monte Carlo (MC code, BEAMnrc/EGSnrc. To generate the initial beam shape and spectra we conducted full simulations of an X-ray tube, filters and beam shapers for a Siemens Emotion CT. The simulation output files were analyzed to calculate projections of a phantom with inserts. A simple reconstruction algorithm (FBP using a Ram-Lak filter was applied to calculate the pixel values, which represent an attenuation coefficient, normalized in such a way to give zero for water (Hounsfield unit (HU. Measured and Monte Carlo calculated CT numbers were compared. The average deviation between measured and simulated CT numbers was 4 ± 4 HU and the standard deviation σ was 49 ± 4 HU. The simulation also correctly predicted the behaviour of H-materials compared to a Gammex tissue substitutes. We believe the developed approach represents a useful new tool for evaluating the effect of CT scanner and phantom parameters on CT number values.

  19. Interleaving cerebral CT perfusion with neck CT angiography. Pt. I. Proof of concept and accuracy of cerebral perfusion values

    Energy Technology Data Exchange (ETDEWEB)

    Oei, Marcel T.H.; Meijer, Frederick J.A.; Woude, Willem-Jan van der; Smit, Ewoud J.; Ginneken, Bram van; Prokop, Mathias; Manniesing, Rashindra [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, P.O. Box 9101, Nijmegen (Netherlands)

    2017-06-15

    We present a novel One-Step-Stroke protocol for wide-detector CT scanners that interleaves cerebral CTP with volumetric neck CTA (vCTA). We evaluate whether the resulting time gap in CTP affects the accuracy of CTP values. Cerebral CTP maps were retrospectively obtained from 20 patients with suspicion of acute ischemic stroke and served as the reference standard. To simulate a 4 s gap for interleaving CTP with vCTA, we eliminated one acquisition at various time points of CTP starting from the bolus-arrival-time(BAT). Optimal timing of the vCTA was evaluated. At the time point with least errors, we evaluated elimination of a second time point (6 s gap). Mean absolute percentage errors of all perfusion values remained below 10 % in all patients when eliminating any one time point in the CTP sequence starting from the BAT. Acquiring the vCTA 2 s after reaching a threshold of 70HU resulted in the lowest errors (mean <3.0 %). Eliminating a second time point still resulted in mean errors <3.5 %. CBF/CBV showed no significant differences in perfusion values except MTT. However, the percentage errors were always below 10 % compared to the original protocol. Interleaving cerebral CTP with neck CTA is feasible with minor effects on the perfusion values. (orig.)

  20. Comparison of CT number calibration techniques for CBCT-based dose calculation

    Energy Technology Data Exchange (ETDEWEB)

    Dunlop, Alex [The Royal Marsden NHS Foundation Trust, Joint Department of Physics, Institute of Cancer Research, London (United Kingdom); The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom); McQuaid, Dualta; Nill, Simeon; Hansen, Vibeke N.; Oelfke, Uwe [The Royal Marsden NHS Foundation Trust, Joint Department of Physics, Institute of Cancer Research, London (United Kingdom); Murray, Julia; Bhide, Shreerang; Harrington, Kevin [The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom); The Institute of Cancer Research, London (United Kingdom); Poludniowski, Gavin [Karolinska University Hospital, Department of Medical Physics, Stockholm (Sweden); Nutting, Christopher [The Institute of Cancer Research, London (United Kingdom); Newbold, Kate [The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom)

    2015-12-15

    The aim of this work was to compare and validate various computed tomography (CT) number calibration techniques with respect to cone beam CT (CBCT) dose calculation accuracy. CBCT dose calculation accuracy was assessed for pelvic, lung, and head and neck (H and N) treatment sites for two approaches: (1) physics-based scatter correction methods (CBCT{sub r}); (2) density override approaches including assigning water density to the entire CBCT (W), assignment of either water or bone density (WB), and assignment of either water or lung density (WL). Methods for CBCT density assignment within a commercially available treatment planning system (RS{sub auto}), where CBCT voxels are binned into six density levels, were assessed and validated. Dose-difference maps and dose-volume statistics were used to compare the CBCT dose distributions with the ground truth of a planning CT acquired the same day as the CBCT. For pelvic cases, all CTN calibration methods resulted in average dose-volume deviations below 1.5 %. RS{sub auto} provided larger than average errors for pelvic treatments for patients with large amounts of adipose tissue. For H and N cases, all CTN calibration methods resulted in average dose-volume differences below 1.0 % with CBCT{sub r} (0.5 %) and RS{sub auto} (0.6 %) performing best. For lung cases, WL and RS{sub auto} methods generated dose distributions most similar to the ground truth. The RS{sub auto} density override approach is an attractive option for CTN adjustments for a variety of anatomical sites. RS{sub auto} methods were validated, resulting in dose calculations that were consistent with those calculated on diagnostic-quality CT images, for CBCT images acquired of the lung, for patients receiving pelvic RT in cases without excess adipose tissue, and for H and N cases. (orig.) [German] Ziel dieser Arbeit ist der Vergleich und die Validierung mehrerer CT-Kalibrierungsmethoden zur Dosisberechnung auf der Grundlage von Kegelstrahlcomputertomographie

  1. Comparative accuracy of CT perfusion in diagnosing acute ischemic stroke: A systematic review of 27 trials.

    Science.gov (United States)

    Shen, Jiantong; Li, Xianglian; Li, Youping; Wu, Bing

    2017-01-01

    To systematically evaluate and compare the diagnostic accuracy of CT perfusion (CTP), non-enhanced computed tomography (NCCT) and computed tomography angiography (CTA) in detecting acute ischemic stroke. We searched seven databases and screened the reference lists of the included studies. The risk of bias in the study quality was assessed using QUADASII. We produced paired forest plots in RevMan to show the variation of the sensitivity and specificity estimates together with their 95% CI. We used a hierarchical summary ROC model to summarize the sensitivity and specificity of CTP in detecting ischemic stroke. We identified 27 studies with a total of 2168 patients. The pooled sensitivity of CTP for acute ischemic stroke was 82% (95% CI 75-88%), and the specificity was 96% (95% CI 89-99%). CTP was more sensitive than NCCT and had a similar accuracy with CTA. There were no statistically significant differences in the sensitivity and specificity between patients who underwent CTP within 6 hours of symptom onset and beyond 6 hours after symptom onset. No adverse events were reported in the included studies. CTP is more accurate than NCCT and has similar accuracy to CTA in detecting acute ischemic stroke. However, the evidence is not strong. There is potential benefit of using CTP to select stroke patients for treatment, but more high-quality evidence is needed to confirm this result.

  2. Accuracy of the detection of infratentorial stroke lesions using perfusion CT: an experimenter-blinded study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In Hyouk; Kim, Myung Soon; Kim, Young Ju; Lee, Myeong Sub [Yonsei University, Department of Radiology, Wonju College of Medicine, Wonju (Korea, Republic of); You, Joshua H. [Center for Health, Wellness, Fitness, Prevention, and Healing Across the Life Span, Department of Physical Therapy, Graduate School of Rehabilitation Science, Yonsei University, Center for Movement Impairment Solutions, Wonju City (Korea, Republic of); Lee, Ji Yong [Yonsei University, Department of Neurology, Wonju College of Medicine, Wonju (Korea, Republic of); Whang, Kum [Yonsei University, Department of Neurosurgery, Wonju College of Medicine, Wonju (Korea, Republic of)

    2010-12-15

    Although perfusion CT (PCT) for the detection of supratentorial stroke is well established, there is a dearth of evidence of its effectiveness in the detection of infratentorial stroke. Hence, this study compared sensitivity, specificity, and accuracy of PCT maps between infratentorial and supratentorial stroke lesions. One hundred patients with acute stroke who had successfully undergone near whole-brain PCT with the toggling table technique and follow-up MRI were included. Wilcoxon Mann-Whitney test was performed at P < 0.01. There was no significant statistical difference in the accuracy (91.79% vs. 93.23% in regional cerebral blood volume; 92.26% vs. 95.31% in regional cerebral blood flow; 89.17% vs. 92.71% in mean transit time; 89.76% vs. 92.19% in time to peak; P > 0.01 in all PCT maps) between supratentorial and infratentorial stroke. Also, there was no remarkable difference in both sensitivity and specificity of PCT maps. This was the first study to investigate the accuracy of PCT with the toggling table technique in detection of infratentorial stroke lesions. Clinically, PCT is highly reliable and accurate in detecting infratentorial stroke lesions. (orig.)

  3. Noncontrast perfusion single-photon emission CT/CT scanning: a new test for the expedited, high-accuracy diagnosis of acute pulmonary embolism.

    Science.gov (United States)

    Lu, Yang; Lorenzoni, Alice; Fox, Josef J; Rademaker, Jürgen; Vander Els, Nicholas; Grewal, Ravinder K; Strauss, H William; Schöder, Heiko

    2014-05-01

    Standard ventilation and perfusion (V˙/Q˙) scintigraphy uses planar images for the diagnosis of pulmonary embolism (PE). To evaluate whether tomographic imaging improves the diagnostic accuracy of the procedure, we compared noncontrast perfusion single-photon emission CT (Q˙-SPECT)/CT scans with planar V˙/Q˙scans in patients at high risk for PE. Between 2006 and 2010, most patients referred for diagnosis of PE underwent both Q˙-SPECT/CT scan and planar V˙/Q˙scintigraphy. All scans were reviewed retrospectively by four observers; planar scans were read with modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II and Prospective Investigative Study of Pulmonary Embolism Diagnosis (PISA-PED) criteria. On Q˙-SPECT/CT scan, any wedge-shaped peripheral perfusion defect occupying > 50% of a segment without corresponding pulmonary parenchymal or pleural disease was considered to show PE. The final diagnosis was established with a composite reference standard that included ECG, ultrasound of lower-extremity veins, D-dimer levels, CT pulmonary angiography (when available), and clinical follow-up for at least 3 months. One hundred six patients with cancer and mean Wells score of 4.4 had sufficient follow-up; 22 patients were given a final diagnosis of PE, and 84 patients were given a final diagnosis of no PE. According to PIOPED II, 13 studies were graded as intermediate probability. Sensitivity and specificity for PE were 50% and 98%, respectively, based on PIOPED II criteria; 86% and 93%, respectively, based on PISA-PED criteria; and 91% and 94%, respectively, based on Q˙-SPECT/CT scan. Seventy-six patients had additional relevant findings on the CT image of the Q˙-SPECT/CT scan. Noncontrast Q˙-SPECT/CT imaging has a higher accuracy than planar V˙/Q˙imaging based on PIOPED II criteria in patients with cancer and a high risk for PE.

  4. Hepatic perfusion in a tumor model using DCE-CT: an accuracy and precision study

    Science.gov (United States)

    Stewart, Errol E.; Chen, Xiaogang; Hadway, Jennifer; Lee, Ting-Yim

    2008-08-01

    In the current study we investigate the accuracy and precision of hepatic perfusion measurements based on the Johnson and Wilson model with the adiabatic approximation. VX2 carcinoma cells were implanted into the livers of New Zealand white rabbits. Simultaneous dynamic contrast-enhanced computed tomography (DCE-CT) and radiolabeled microsphere studies were performed under steady-state normo-, hyper- and hypo-capnia. The hepatic arterial blood flows (HABF) obtained using both techniques were compared with ANOVA. The precision was assessed by the coefficient of variation (CV). Under normo-capnia the microsphere HABF were 51.9 ± 4.2, 40.7 ± 4.9 and 99.7 ± 6.0 ml min-1 (100 g)-1 while DCE-CT HABF were 50.0 ± 5.7, 37.1 ± 4.5 and 99.8 ± 6.8 ml min-1 (100 g)-1 in normal tissue, tumor core and rim, respectively. There were no significant differences between HABF measurements obtained with both techniques (P > 0.05). Furthermore, a strong correlation was observed between HABF values from both techniques: slope of 0.92 ± 0.05, intercept of 4.62 ± 2.69 ml min-1 (100 g)-1 and R2 = 0.81 ± 0.05 (P liver diseases.

  5. Reduction of Cone-Beam CT scan time without compromising the accuracy of the image registration in IGRT

    DEFF Research Database (Denmark)

    Westberg, Jonas; Jensen, Henrik R; Bertelsen, Anders;

    2010-01-01

    In modern radiotherapy accelerators are equipped with 3D cone-beam CT (CBCT) which is used to verify patient position before treatment. The verification is based on an image registration between the CBCT acquired just before treatment and the CT scan made for the treatment planning. The purpose...... of this study is to minimise the scan time of the CBCT without compromising the accuracy of the image registration in IGRT....

  6. ACCURACY AND PRECISION OF A METHOD TO STUDY KINEMATICS OF THE TEMPOROMANDIBULAR JOINT: COMBINATION OF MOTION DATA AND CT IMAGING

    OpenAIRE

    Baltali, Evre; Zhao, Kristin D.; Koff, Matthew F.; Keller, Eugene E.; An, Kai-Nan

    2008-01-01

    The purpose of the study was to test the precision and accuracy of a method used to track selected landmarks during motion of the temporomandibular joint (TMJ). A precision phantom device was constructed and relative motions between two rigid bodies on the phantom device were measured using optoelectronic (OE) and electromagnetic (EM) motion tracking devices. The motion recordings were also combined with a 3D CT image for each type of motion tracking system (EM+CT and OE+CT) to mimic methods ...

  7. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark

    DEFF Research Database (Denmark)

    Hansen, David Christoffer; Seco, Joao; Sørensen, Thomas Sangild

    2015-01-01

    Background. Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in...

  8. Absolute measurement of the effective atomic number and the electron density by using dual-energy CT images

    Science.gov (United States)

    Kim, Dae-Hong; Lee, Won-Hyung; Jeon, Sung-Soo; Kim, Hee-Joung

    2012-12-01

    Material decomposition using dual-energy and material-selective techniques was performed using computed-tomography (CT)-generated reconstructed images. Previous work using the dual-energy method focused on extracting the effective atomic number and the electron density of materials to confirm the dosimetric accuracy in radiation therapy. Dual-energy methods mostly depend on the device generating the X-rays, such as a synchrotron, and on dose verification for radiation treatment planning. Information obtained from CT imaging is important both in diagnosis and in planning radiation therapy. In a clinical setting, CT images are usually displayed as Houndsfield units (HU), which are extracted from the attenuation coefficient of a material. The attenuation coefficient is calculated using the effective atomic number and the electron density of a material; thus, information expressed in HU can be converted into the effective atomic number and the electron density by using the dual-energy equation. This study was performed using realistic Xray spectra to differentiate between the contrast media and plaque in vascular images. Our results suggest that the effective atomic number and electron density are useful in distinguishing between two adjacent materials with similar HUs.

  9. Learning linear spatial-numeric associations improves accuracy of memory for numbers

    Directory of Open Access Journals (Sweden)

    Clarissa Ann Thompson

    2016-01-01

    Full Text Available Memory for numbers improves with age and experience. One potential source of improvement is a logarithmic-to-linear shift in children’s representations of magnitude. To test this, Kindergartners and second graders estimated the location of numbers on number lines and recalled numbers presented in vignettes (Study 1. Accuracy at number-line estimation predicted memory accuracy on a numerical recall task after controlling for the effect of age and ability to approximately order magnitudes (mapper status. To test more directly whether linear numeric magnitude representations caused improvements in memory, half of children were given feedback on their number-line estimates (Study 2. As expected, learning linear representations was again linked to memory for numerical information even after controlling for age and mapper status. These results suggest that linear representations of numerical magnitude may be a causal factor in development of numeric recall accuracy.

  10. Learning Linear Spatial-Numeric Associations Improves Accuracy of Memory for Numbers.

    Science.gov (United States)

    Thompson, Clarissa A; Opfer, John E

    2016-01-01

    Memory for numbers improves with age and experience. One potential source of improvement is a logarithmic-to-linear shift in children's representations of magnitude. To test this, Kindergartners and second graders estimated the location of numbers on number lines and recalled numbers presented in vignettes (Study 1). Accuracy at number-line estimation predicted memory accuracy on a numerical recall task after controlling for the effect of age and ability to approximately order magnitudes (mapper status). To test more directly whether linear numeric magnitude representations caused improvements in memory, half of children were given feedback on their number-line estimates (Study 2). As expected, learning linear representations was again linked to memory for numerical information even after controlling for age and mapper status. These results suggest that linear representations of numerical magnitude may be a causal factor in development of numeric recall accuracy.

  11. Spectral CT in patients with small HCC: investigation of image quality and diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Peijie; Gao, Jianbo [The First Affiliated Hospital of Zhengzhou University, The Department of Radiology, Zhengzhou, Henan Province (China); Lin, Xiao Zhu; Chen, Kemin [Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China)

    2012-10-15

    To assess image quality and diagnostic accuracy of monochromatic imaging from spectral CT in patients with small HCC ({<=}3 cm). Twenty-seven patients with 31 HCC underwent spectral CT to generate conventional 140-kVp polychromatic images (group A) and monochromatic images with energy levels from 40 to 140 keV (group B) during the late arterial phase (LAP) and the portal venous phase (PVP). Two-sample t tests compared the tumour-to-liver contrast-to-noise ratio (CNR) and mean image noise. Lesion detection for LAP, reader confidence and readers' subjective evaluations of image quality were recorded. Highest CNRs in group B were distributed at 40, 50 and 70 keV. Higher CNR values and lesion conspicuity scores (LCS) were obtained in group B than in group A (CNR 3.36 {+-} 2.07 vs. 1.47 {+-} 0.89 in LAP; 2.29 {+-} 2.26 vs. 1.58 {+-} 1.75 in PVP; LCS 2.82, 2.84, 2.63 and 2.53 at 40-70 keV, respectively, vs. 1.95) (P < 0.001). Lowest image noise for group B was at 70 keV, resulting in higher image quality than that in group A (4.70 vs. 4.07; P < 0.001). Monochromatic energy levels of 40-70 keV can increase detectability in small HCC and this increase might not result in image quality degradation. (orig.)

  12. Evaluation of a bilinear model for attenuation correction using CT numbers generated from a parametric method.

    Science.gov (United States)

    Martinez, L C; Calzado, A

    2016-01-01

    A parametric model is used for the calculation of the CT number of some selected human tissues of known compositions (Hi) in two hybrid systems, one SPECT-CT and one PET-CT. Only one well characterized substance, not necessarily tissue-like, needs to be scanned with the protocol of interest. The linear attenuation coefficients of these tissues for some energies of interest (μ(i)) have been calculated from their tabulated compositions and the NIST databases. These coefficients have been compared with those calculated with the bilinear model from the CT number (μ(B)i). No relevant differences have been found for bones and lung. In the soft tissue region, the differences can be up to 5%. These discrepancies are attributed to the different chemical composition for the tissues assumed by both methods.

  13. [Influence of interpolation method and sampling number on spatial prediction accuracy of soil Olsen-P].

    Science.gov (United States)

    Sun, Yi-xiang; Wu, Chuan-zhou; Zhu, Ke-bao; Cui, Zhen-ling; Chen, Xin-ping; Zhang, Fu-suo

    2009-03-01

    Different from the large scale farm management in Europe and America, the scattered farmland management in China made the spatial variability of soil nutrients at county scale in this country more challenging. Taking soil Olsen-P in Wuhu County as an example, the influence of interpolation method and sampling number on the spatial prediction accuracy of soil nutrients was evaluated systematically. The results showed that local polynomial method, ordinary kriging, simple kriging, and disjunctive kriging had higher spatial prediction accuracy than the other interpolation methods. Considering of its simplicity, ordinary kriging was recommended to evaluate the spatial variability of soil Olsen-P within a county. The spatial prediction accuracy would increase with increasing soil sampling number. Taking the spatial prediction accuracy and soil sampling cost into consideration, the optimal sampling number should be from 500 to 1000 to evaluate the spatial variability of soil Olsen-P at county scale.

  14. Diagnostic accuracy of 64-slice multidetector CT for detection of in-stent restenosis in an unselected, consecutive patient population

    Energy Technology Data Exchange (ETDEWEB)

    Haraldsdottir, Sigurdis, E-mail: sigurdisha@gmail.com [Boston Medical Center, 72 East Concord Street (Evans 124), Boston, MA, 02118 (United States); Gudnason, Thorarinn, E-mail: thorgudn@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Sigurdsson, Axel F., E-mail: axelfsig@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Gudjonsdottir, Jonina, E-mail: jonina@rd.is [Rontgen Domus Medica, Egilsgata 3, 101 Reykjavik (Iceland); Lehman, Sam J., E-mail: slehman@partners.org [Massachusetts General Hospital, 165 Cambridge Street, Suite 400, Boston, MA 02114 (United States); Eyjolfsson, Kristjan, E-mail: kristey@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Scheving, Sigurpall S., E-mail: sigurpal@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland); Gibson, C. Michael, E-mail: mgibson@perfuse.org [Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02115 (United States); Hoffmann, Udo, E-mail: uhoffmann@partners.org [Massachusetts General Hospital, 165 Cambridge Street, Suite 400, Boston, MA 02114 (United States); Jonsdottir, Birna, E-mail: birna@rd.is [Rontgen Domus Medica, Egilsgata 3, 101 Reykjavik (Iceland); Andersen, Karl, E-mail: andersen@landspitali.is [Landspitali University Hospital, Hringbraut, 101 Reykjavik (Iceland)

    2010-11-15

    Objectives: To investigate the diagnostic accuracy of 64-slice multidetector computed tomography (64-CT) for detection of in-stent restenosis (ISR) in an unselected, consecutive patient population. Background: Detection of in-stent restenosis by cardiac CT would be a major advance for the evaluation of patients suspected of having ISR. However, the diagnostic accuracy of current generation 64-CT in this context is not fully established. Methods: We conducted a prospective study on patients with stable angina or acute coronary syndrome with no prior history of coronary artery disease. Six months after percutaneous coronary intervention (PCI) with stent placement they underwent a 64-CT scan (Toshiba Multi-Slice Aquilion 64) and consequently a repeat coronary angiography for comparison. Cardiac CT data sets were analyzed for the presence of in-stent restenosis by two independent expert readers blinded to the coronary angiographic data. Results: Ninety-three patients with a total of 140 stents were evaluated. Males comprised 82% of the study group and the mean age was 63 {+-} 10 years. The mean time from PCI to the repeat coronary angiography was 208 {+-} 37 days and the mean time from 64-CT to repeat coronary angiography was 3.7 {+-} 4.9 days. The restenosis rate according to coronary angiography was 26%. Stent diameter, strut thickness, heart rate and body mass index (BMI) significantly affected image quality. The sensitivity, specificity, positive and negative predictive values of 64-CT for detection of in-stent restenosis were 27%, 95%, 67% and 78%, respectively. Conclusions: Current generation, 64-slice CT, remains limited in its ability to accurately detect in-stent restenosis.

  15. High-resolution CT of nontuberculous mycobacterium infection in adult CF patients: diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    McEvoy, Sinead; Lavelle, Lisa; Kilcoyne, Aoife; McCarthy, Colin; Dodd, Jonathan D. [St. Vincent' s University Hospital, Department of Radiology, Dublin (Ireland); DeJong, Pim A. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Loeve, Martine; Tiddens, Harm A.W.M. [Erasmus MC-Sophia Children' s Hospital, Department of Radiology, Department of Pediatric Pulmonology and Allergology, Rotterdam (Netherlands); McKone, Edward; Gallagher, Charles G. [St. Vincent' s University Hospital, Department of Respiratory Medicine and National Referral Centre for Adult Cystic Fibrosis, Dublin (Ireland)

    2012-12-15

    To determine the diagnostic accuracy of high-resolution computed tomography (HRCT) for the detection of nontuberculous mycobacterium infection (NTM) in adult cystic fibrosis (CF) patients. Twenty-seven CF patients with sputum-culture-proven NTM (NTM+) underwent HRCT. An age, gender and spirometrically matched group of 27 CF patients without NTM (NTM-) was included as controls. Images were randomly and blindly analysed by two readers in consensus and scored using a modified Bhalla scoring system. Significant differences were seen between NTM (+) and NTM (-) patients in the severity of the bronchiectasis subscore [45 % (1.8/4) vs. 35 % (1.4/4), P = 0.029], collapse/consolidation subscore [33 % (1.3/3) vs. 15 % (0.6/3)], tree-in-bud/centrilobular nodules subscore [43 % (1.7/3) vs. 25 % (1.0/3), P = 0.002] and the total CT score [56 % (18.4/33) vs. 46 % (15.2/33), P = 0.002]. Binary logistic regression revealed BMI, peribronchial thickening, collapse/consolidation and tree-in-bud/centrilobular nodules to be predictors of NTM status (R{sup 2} = 0.43). Receiver-operator curve analysis of the regression model showed an area under the curve of 0.89, P < 0.0001. In adults with CF, seven or more bronchopulmonary segments showing tree-in-bud/centrilobular nodules on HRCT is highly suggestive of NTM colonisation. (orig.)

  16. Adrenal adenomas: relationship between histologic lipid-rich cells and CT attenuation number

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Takayuki E-mail: yamataka@rad.med.tohoku.ac.jp; Ishibashi, Tadashi; Saito, Haruo; Matsuhashi, Toshio; Majima, Kazuhiro; Tsuda, Masashi; Takahashi, Shoki; Moriya, Takuya

    2003-11-01

    Objective: To evaluate the relationship between lipid-rich cells of the adrenal adenoma and precontrast computed tomographic (CT) attenuation numbers in three clinical groups. Materials and Methods: Thirty-five surgically resected adrenal adenomas were used. The clinical diagnoses of the patients included 13 cases of primary aldosteronism, 15 cases of Cushing's syndrome, and 7 non-functioning tumors. The number of lipid-rich clear cells was counted using a microscopic eyepiece grid that contained 100 squares. The results were expressed as the percentages of lipid-rich areas. Results: There was a strong inverse linear relationship between the percentage of lipid-rich cells and the precontrast CT attenuation number (R{sup 2}=0.724, P<0.0001). There were significantly more lipid-rich cells in the primary aldosteronism and non-functioning tumor cases compared to cases of Cushing's syndrome (P=0.007 and 0.015, respectively). The CT attenuation numbers of the primary aldosteronism cases were significantly lower than those of Cushing's syndrome (P=0.0052). Furthermore, the CT attenuation numbers of the non-functioning tumor cases were lower than those of Cushing's syndrome cases. Conclusion: We showed that adrenal adenomas in primary aldosteronism and non-functioning tumors contain significantly more lipid-rich cells than those in Cushing's syndrome. They also showed significantly lower attenuation than that in Cushing's syndrome on CT scans. Our results suggest that precontrast CT attenuation numbers may be helpful in the differentiation of adenomas from non-adenomatous lesions, which include malignancies.

  17. Semi-automated scoring of pulmonary emphysema from X-ray CT: Trainee reproducibility and accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Owrangi, Amir M., E-mail: aowrangi@robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Entwistle, Brandon, E-mail: Brandon.Entwistle@londonhospitals.ca; Lu, Andrew, E-mail: Andrew.Lu@londonhospitals.ca; Chiu, Jack, E-mail: Jack.Chiu@londonhospitals.ca; Hussain, Nabil, E-mail: Nabil.Hussain@londonhospitals.ca; Etemad-Rezai, Roya, E-mail: Roya.EtemadRezai@lhsc.on.ca; Parraga, Grace, E-mail: gparraga@robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London (Canada); Graduate Program in Biomedical Engineering, Department of Medical Imaging, Department of Medical Biophysics, The University of Western Ontario, London (Canada)

    2013-11-01

    Objective: We developed a semi-automated tool to quantify emphysema from thoracic X-ray multi-detector (64-slice) computed tomography (CT) for training purposes and multi-reader studies. Materials and Methods: Thoracic X-ray CT was acquired in 93 ex-smokers, who were evaluated by six trainees with little or no expertise (trainees) and a single experienced thoracic radiologist (expert). A graphic user interface (GUI) was developed for emphysema quantification based on the percentile of lung where a score of 0 = no abnormalities, 1 = 1–25%, 2 = 26–50%, 3 = 51–75% and 4 = 76–100% for each lung side/slice. Trainees blinded to subject characteristics scored randomized images twice; accuracy was determined by comparison to expert scores, density histogram 15th percentile (HU{sub 15}), relative area at −950 HU (RA{sub 950}), low attenuation clusters at −950 HU (LAC{sub 950}), −856 HU (LAC{sub 856}) and the diffusing capacity for carbon monoxide (DL{sub CO%pred}). Intra- and inter-observer reproducibility was evaluated using coefficients-of-variation (COV), intra-class (ICC) and Pearson correlations. Results: Trainee–expert correlations were significant (r = 0.85–0.97, p < 0.0001) and a significant trainee bias (0.15 ± 0.22) was observed. Emphysema score was correlated with RA{sub 950} (r = 0.88, p < 0.0001), HU{sub 15} (r = −0.77, p < 0.0001), LAC{sub 950} (r = 0.76, p < 0.0001), LAC{sub 856} (r = 0.74, p = 0.0001) and DL{sub CO%pred} (r = −0.71, p < 0.0001). Intra-observer reproducibility (COV = 4–27%; ICC = 0.75–0.94) was moderate to high for trainees; intra- and inter-observer COV were negatively and non-linearly correlated with emphysema score. Conclusion: We developed a GUI for rapid and interactive emphysema scoring that allows for comparison of multiple readers with clinical and radiological standards.

  18. Comparison of diagnostic accuracy between 18F-FDG PET and PET/CT for pulmonary neoplasm

    Institute of Scientific and Technical Information of China (English)

    CHEN Yangchun; CHEN Ping; TIAN Jiahe; CAI Xin; YE Guangchun; DENG Huaifu; YANG Xiaofeng

    2009-01-01

    Aimed at comparing diagnostic accuracy of 18F-FDG PET with PET/CT for pulmonary neoplasm,a study based on multi-center clinical trial of the diagnoses,in randomized and semi-blind ways,was executed from January 2006 to June 2007.It included 55 patients,i.e.16 with histopathologically proved lung tumors,16 with tuberculosis and 23 with benign lesions (inflammation,pseudotumor,granuloma,fibrosis and others).The histopathologic and clinic results were served as reference standard.Statistical significances in pulmonary nodule diagnosis between 18F-FDG PET and PET/CT were determined with 95% confidence interval obtained by ROC analysis.The 18F-FDG PET detected lung neoplasm with a sensitivity of 87.5% (14/16),a specificity of 59.0% (23/39),an accuracy of 67.3% (37/55) and a positive-likelihood ratio of 2.13.The 18F-FDG PET/CT detected lung neoplasm with a sensitivity of 93.8% (15/16),a specificity of 61.5% (24/39),an accuracy of 70.9% (39/55) and a positive-likelihood ratio of 2.43.The area under curves (AUC) of 18F-FDG PET and PET/CT were 0.803±0.068 and 0.799±0.063,respectively.It can be concluded that the diagnostic accuracy for malignant pulmonary nodules between 18F-FDG PET and PET/CT was not statistically different.

  19. Understanding less than nothing: children's neural response to negative numbers shifts across age and accuracy.

    Science.gov (United States)

    Gullick, Margaret M; Wolford, George

    2013-01-01

    We examined the brain activity underlying the development of our understanding of negative numbers, which are amounts lacking direct physical counterparts. Children performed a paired comparison task with positive and negative numbers during an fMRI session. As previously shown in adults, both pre-instruction fifth-graders and post-instruction seventh-graders demonstrated typical behavioral and neural distance effects to negative numbers, where response times and parietal and frontal activity increased as comparison distance decreased. We then determined the factors impacting the distance effect in each age group. Behaviorally, the fifth-grader distance effect for negatives was significantly predicted only by positive comparison accuracy, indicating that children who were generally better at working with numbers were better at comparing negatives. In seventh-graders, negative number comparison accuracy significantly predicted their negative number distance effect, indicating that children who were better at working with negative numbers demonstrated a more typical distance effect. Across children, as age increased, the negative number distance effect increased in the bilateral IPS and decreased frontally, indicating a frontoparietal shift consistent with previous numerical development literature. In contrast, as negative comparison task accuracy increased, the parietal distance effect increased in the left IPS and decreased in the right, possibly indicating a change from an approximate understanding of negatives' values to a more exact, precise representation (particularly supported by the left IPS) with increasing expertise. These shifts separately indicate the effects of increasing maturity generally in numeric processing and specifically in negative number understanding.

  20. Bicuspid aortic valves: Diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, David J., E-mail: david.murphy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); McEvoy, Sinead H., E-mail: s.mcevoy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); Iyengar, Sri, E-mail: sri.iyengar@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Feuchtner, Gudrun, E-mail: Gudrun.Feuchtner@i-med.ac.at [Department of Radiology, Innsbruck Medical University, Anichstr. 35, A-6020 Innsbruck (Austria); Cury, Ricardo C., E-mail: r.cury@baptisthealth.net [Department of Radiology, Baptist Cardiac and Vascular Institute, 8900 North Kendall Drive, Miami, FL 33176 (United States); Roobottom, Carl, E-mail: carl.roobottom@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Plymouth University Peninsula Schools of Medicine and Dentistry (United Kingdom); Baumueller, Stephan, E-mail: Hatem.Alkadhi@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Alkadhi, Hatem, E-mail: stephan.baumueller@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Dodd, Jonathan D., E-mail: jonniedodd@gmail.com [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland)

    2014-08-15

    Objectives: To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. Materials and methods: The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Results: Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P = 0.001). Kappa analysis = 0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥3.8 cm{sup 2}, 3.2 cm and 1.6 mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P < 0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54–1.0), 100%, 100% and 70% respectively. Conclusion: The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT

  1. Quantitative imaging of electron density and effective atomic number using phase contrast CT

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen Guanghong, E-mail: gchen7@wisc.ed [Department of Medical Physics, University of Wisconsin-Madison, WI 53705 (United States)

    2010-05-07

    Compared to single energy CT, which only provides information for x-ray linear attenuation coefficients, dual-energy CT is able to obtain both the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual-energy CT, a novel quantitative imaging method based on phase contrast CT is presented. Rather than requiring two projection data sets with different x-ray energy spectra, diffraction-grating-based phase contrast CT is capable of reconstructing images of both linear attenuation and refractive index decrement from the same projection data using a single x-ray energy spectra. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Two physical phantoms were constructed and used to validate the presented method. Experimental results demonstrate that (1) electron density can be accurately determined from refractive index decrement through a linear relationship, and (2) the effective atomic number can be explicitly derived from the ratio of the linear attenuation to refractive index decrement using a power function plus a constant. The presented method will provide insight into the technique of material separation and find its use in medical and industrial applications.

  2. Quantitative imaging of electron density and effective atomic number using phase contrast CT

    Science.gov (United States)

    Qi, Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen, Guang-Hong

    2010-05-01

    Compared to single energy CT, which only provides information for x-ray linear attenuation coefficients, dual-energy CT is able to obtain both the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual-energy CT, a novel quantitative imaging method based on phase contrast CT is presented. Rather than requiring two projection data sets with different x-ray energy spectra, diffraction-grating-based phase contrast CT is capable of reconstructing images of both linear attenuation and refractive index decrement from the same projection data using a single x-ray energy spectra. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Two physical phantoms were constructed and used to validate the presented method. Experimental results demonstrate that (1) electron density can be accurately determined from refractive index decrement through a linear relationship, and (2) the effective atomic number can be explicitly derived from the ratio of the linear attenuation to refractive index decrement using a power function plus a constant. The presented method will provide insight into the technique of material separation and find its use in medical and industrial applications.

  3. Accuracy of bone SPECT/CT for identifying hardware loosening in patients who underwent lumbar fusion with pedicle screws

    Energy Technology Data Exchange (ETDEWEB)

    Hudyana, Hendrah; Maes, Alex [AZ Groeninge, Department of Nuclear Medicine, Kortrijk (Belgium); University Hospital Leuven, Department of Morphology and Medical Imaging, Leuven (Belgium); Vandenberghe, Thierry; Fidlers, Luc [AZ Groeninge, Department of Neurosurgery, Kortrijk (Belgium); Sathekge, Mike [University of Pretoria, Department of Nuclear Medicine, Pretoria (South Africa); Nicolai, Daniel [AZ Groeninge, Department of Nuclear Medicine, Kortrijk (Belgium); Wiele, Christophe van de [AZ Groeninge, Department of Nuclear Medicine, Kortrijk (Belgium); University Ghent, Department of Radiology and Nuclear Medicine, Ghent (Belgium)

    2016-02-15

    The aim of this retrospective study was to evaluate the accuracy of bone SPECT (single photon emission computed tomography)/CT (computed tomography) in diagnosing loosening of fixation material in patients with recurrent or persistent back pain that underwent lumbar arthrodesis with pedicle screws using surgery and clinical follow-up as gold standard A total of 48 patients (median age 49 years, range 21-81 years; 17 men) who had undergone lumbar spinal arthrodesis were included in this retrospective analysis. SPECT/CT results were compared to the gold standard of surgical evaluation or clinical follow-up. Positive SPECT/CT results were considered true positives if findings were confirmed by surgery or if clinical and other examinations were completely consistent with the positive SPECT/CT finding. They were considered false positives if surgical evaluation did not find any loose pedicle screws or if symptoms subsided with non-surgical therapy. Negative SPECT/CT scans were considered true negatives if symptoms either improved without surgical intervention or remained stable over a minimum follow-up period of 6 months. Negative SPECT/CT scans were determined to be false negatives if surgery was still required and loosening of material was found. The median length of time from primary surgery to bone SPECT/CT referral was 29.5 months (range 12-192 months). Median follow-up was 18 months (range 6-57) for subjects who did not undergo surgery. Thirteen of the 48 patients were found to be positive for loosening on bone SPECT/CT. Surgical evaluation (8 patients) and clinical follow-up (5 patients) showed that bone SPECT/CT correctly predicted loosening in 9 of 13 patients, while it falsely diagnosed loosening in 4 patients. Of 35 negative bone SPECT/CT scans, 12 were surgically confirmed. In 18 patients, bone SPECT/CT revealed lesions that could provide an alternative explanation for the symptoms of pain (active facet degeneration in 14 patients, and disc and sacroiliac

  4. Accuracy and variability of texture-based radiomics features of lung lesions across CT imaging conditions

    Science.gov (United States)

    Zheng, Yuese; Solomon, Justin; Choudhury, Kingshuk; Marin, Daniele; Samei, Ehsan

    2017-03-01

    Texture analysis for lung lesions is sensitive to changing imaging conditions but these effects are not well understood, in part, due to a lack of ground-truth phantoms with realistic textures. The purpose of this study was to explore the accuracy and variability of texture features across imaging conditions by comparing imaged texture features to voxel-based 3D printed textured lesions for which the true values are known. The seven features of interest were based on the Grey Level Co-Occurrence Matrix (GLCM). The lesion phantoms were designed with three shapes (spherical, lobulated, and spiculated), two textures (homogenous and heterogeneous), and two sizes (diameter Kyoto Kagaku) and imaged using a commercial CT system (GE Revolution) at three CTDI levels (0.67, 1.42, and 5.80 mGy), three reconstruction algorithms (FBP, IR-2, IR-4), four reconstruction kernel types (standard, soft, edge), and two slice thicknesses (0.6 mm and 5 mm). Another repeat scan was performed. Texture features from these images were extracted and compared to the ground truth feature values by percent relative error. The variability across imaging conditions was calculated by standard deviation across a certain imaging condition for all heterogeneous lesions. The results indicated that the acquisition method has a significant influence on the accuracy and variability of extracted features and as such, feature quantities are highly susceptible to imaging parameter choices. The most influential parameters were slice thickness and reconstruction kernels. Thin slice thickness and edge reconstruction kernel overall produced more accurate and more repeatable results. Some features (e.g., Contrast) were more accurately quantified under conditions that render higher spatial frequencies (e.g., thinner slice thickness and sharp kernels), while others (e.g., Homogeneity) showed more accurate quantification under conditions that render smoother images (e.g., higher dose and smoother kernels). Care

  5. Diagnostic accuracy of dual-source CT coronary angiography in patients with atrial fibrillation: Meta analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Gang, E-mail: cjr.sungang@vip.163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Min [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jiang, Zhi-wei [Department of Health Statistics, School of Public Health, Fourth Military Medical University, No. 169, Changle West Road, Xi’an, Shaanxi 710032 (China); Xu, Lin [Department of Medical Cardiology, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Peng, Zhao-hui; Ding, Juan; Li, Li [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jin, Zhi-tao [Department of Cardiology, General Hospital of the Second Artillery, Beijing 100088 (China)

    2013-10-01

    Rationale and objective: To synthesize the available data to underscore the diagnostic accuracy of dual-source CT (DSCT) coronary angiography in patients with atrial fibrillation (AF). Materials and methods: We searched in the electronic databases of PubMed for all published studies that examined patients with AF using DSCT. We used an exact binomial rendition of the bivariate mixed-effects regression model to synthesize the diagnostic data. Results: The positive and negative likelihood ratios (LRs) at the patient level were 6.0 (CI, 3.6–10.1) and 0.03(CI, 0.004–0.2), respectively. The negative predictive values higher than 90% were available for a CAD prevalence <78%. The pooled vessel- and segment-level estimates showed higher positive and negative LRs than the patient-level estimates (15.3 [CI, 9.8–23.9] and 0.1 [CI, 0.07–0.3]; 25.1 [CI, 10.8–58.5] and 0.2 [CI, 0.2–0.3], respectively). No statistically significant heterogeneity between studies and publication bias were found at the patient level estimate. A sensitivity analysis showed that no study influenced the pooled results larger than 0.02. Conclusions: Cardiac angiography with DSCT can be applied as an imaging test for ruling out CAD in patient with AF. However, DSCT angiography may be not an effective tool for risk stratification for the high negative LR at the artery and segment levels.

  6. Effects of adaptive statistical iterative reconstruction on radiation dose reduction and diagnostic accuracy of pediatric abdominal CT

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sohi; Kim, Myung-Joon; Lee, Mi-Jung [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Severance Children' s Hospital, Seoul (Korea, Republic of); Yoon, Choon-Sik [Yonsei University College of Medicine, Department of Radiology, Gangnam Severance Hospital, Seoul (Korea, Republic of); Kim, Dong Wook; Hong, Jung Hwa [Yonsei University College of Medicine, Biostatistics Collaboration Unit, Seoul (Korea, Republic of)

    2014-12-15

    Since children are more radio-sensitive than adults, there is a need to minimize radiation exposure during CT exams. To evaluate the effects of adaptive statistical iterative reconstruction (ASIR) on radiation dose reduction, image quality and diagnostic accuracy in pediatric abdominal CT. We retrospectively reviewed the abdominal CT examinations of 41 children (24 boys and 17 girls; mean age: 10 years) with a low-dose radiation protocol and reconstructed with ASIR (the ASIR group). We also reviewed routine-dose abdominal CT examinations of 41 age- and sex-matched controls reconstructed with filtered-back projection (control group). Image quality was assessed objectively as noise measured in the liver, spleen and aorta, as well as subjectively by three pediatric radiologists for diagnostic acceptability using a four-point scale. Radiation dose and objective image qualities of each group were compared with the paired t-test. Diagnostic accuracy was evaluated by reviewing follow-up imaging studies and medical records in 2012 and 2013. There was 46.3% dose reduction of size-specific dose estimates in ASIR group (from 13.4 to 7.2 mGy) compared with the control group. Objective noise was higher in the liver, spleen and aorta of the ASIR group (P < 0.001). However, the subjective image quality was average or superior in 84-100% of studies. Only one image was subjectively rated as unacceptable by one reviewer. There was only one case with interpretational error in the control group and none in the ASIR group. Use of the ASIR technique resulted in greater than a 45% reduction in radiation dose without impairing subjective image quality or diagnostic accuracy in pediatric abdominal CT, despite increased objective image noise. (orig.)

  7. SU-E-J-19: Accuracy of Dual-Energy CT-Derived Relative Electron Density for Proton Therapy Dose Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, J; Duan, X; Kruse, J; Herman, M [Mayo Clinic, Rochester, MN (United States); Bues, M [Mayo Clinic Arizona, Phoenix, AZ (United States)

    2014-06-01

    Purpose: To determine the suitability of dual-energy CT (DECT) to calculate relative electron density (RED) of tissues for accurate proton therapy dose calculation. Methods: DECT images of RED tissue surrogates were acquired at 80 and 140 kVp. Samples (RED=0.19−2.41) were imaged in a water-equivalent phantom in a variety of configurations. REDs were calculated using the DECT numbers and inputs of the high and low energy spectral weightings. DECT-derived RED was compared between geometric configurations and for variations in the spectral inputs to assess the sensitivity of RED accuracy versus expected values. Results: RED accuracy was dependent on accurate spectral input influenced by phantom thickness and radius from the phantom center. Material samples located at the center of the phantom generally showed the best agreement to reference RED values, but only when attenuation of the surrounding phantom thickness was accounted for in the calculation spectra. Calculated RED changed by up to 10% for some materials when the sample was located at an 11 cm radius from the phantom center. Calculated REDs under the best conditions still differed from reference values by up to 5% in bone and 14% in lung. Conclusion: DECT has previously been used to differentiate tissue types based on RED and Z for binary tissue-type segmentation. To improve upon the current standard of empirical conversion of CT number to RED for treatment planning dose calculation, DECT methods must be able to calculate RED to better than 3% accuracy throughout the image. The DECT method is sensitive to the accuracy of spectral inputs used for calculation, as well as to spatial position in the anatomy. Effort to address adjustments to the spectral calculation inputs based on position and phantom attenuation will be required before DECT-determined RED can achieve a consistent level of accuracy for application in dose calculation.

  8. Application of CT-PSF-based computer-simulated lung nodules for evaluating the accuracy of computer-aided volumetry.

    Science.gov (United States)

    Funaki, Ayumu; Ohkubo, Masaki; Wada, Shinichi; Murao, Kohei; Matsumoto, Toru; Niizuma, Shinji

    2012-07-01

    With the wide dissemination of computed tomography (CT) screening for lung cancer, measuring the nodule volume accurately with computer-aided volumetry software is increasingly important. Many studies for determining the accuracy of volumetry software have been performed using a phantom with artificial nodules. These phantom studies are limited, however, in their ability to reproduce the nodules both accurately and in the variety of sizes and densities required. Therefore, we propose a new approach of using computer-simulated nodules based on the point spread function measured in a CT system. The validity of the proposed method was confirmed by the excellent agreement obtained between computer-simulated nodules and phantom nodules regarding the volume measurements. A practical clinical evaluation of the accuracy of volumetry software was achieved by adding simulated nodules onto clinical lung images, including noise and artifacts. The tested volumetry software was revealed to be accurate within an error of 20 % for nodules >5 mm and with the difference between nodule density and background (lung) (CT value) being 400-600 HU. Such a detailed analysis can provide clinically useful information on the use of volumetry software in CT screening for lung cancer. We concluded that the proposed method is effective for evaluating the performance of computer-aided volumetry software.

  9. Experimental measurement of the correlation between CT number and heavy ion range

    Institute of Scientific and Technical Information of China (English)

    HE Peng-Bo; LI Qiang; LIU Xin-Guo; YE Fei; DAI Zhong-Ying

    2012-01-01

    For precision delivery of the Bragg peak of a heavy-ion beam to a target volume in ion beam therapy,it is necessary to know the tissue stopping power.A general approach to solve this problem in ion beam therapy is to convert X-ray CT (computed tomography) numbers into water-equivalent path length (WEPL) coefficients using a CT-WEPL calibration curve for all voxels traversed by the beam.This work aims at establishing a CT-WEPL coefficient calibration curve for the heavy ion therapy project at IMP,so as to compute the range of carbon ion beams in tissues easily according to the patient CT data.Several tissueequivalent materials wcrc applicd to measure their WEPL coefficients using a high-energy carbon ion beam in this work.A CT-WEPL calibration curve was obtained through fitting the measured data,which can be used directly for dose optimization and facilitates the design of patient treatment plans significantly at IMP.

  10. Improved accuracy of quantitative parameter estimates in dynamic contrast-enhanced CT study with low temporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Mo, E-mail: Sunmo.Kim@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital/University Health Network, Toronto, Ontario M5G 2M9 (Canada); Haider, Masoom A. [Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Imaging, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital/University Health Network, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Yeung, Ivan W. T. [Radiation Medicine Program, Princess Margaret Hospital/University Health Network, Toronto, Ontario M5G 2M9 (Canada); Department of Medical Physics, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario L3Y 2P9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

    2016-01-15

    Purpose: A previously proposed method to reduce radiation dose to patient in dynamic contrast-enhanced (DCE) CT is enhanced by principal component analysis (PCA) filtering which improves the signal-to-noise ratio (SNR) of time-concentration curves in the DCE-CT study. The efficacy of the combined method to maintain the accuracy of kinetic parameter estimates at low temporal resolution is investigated with pixel-by-pixel kinetic analysis of DCE-CT data. Methods: The method is based on DCE-CT scanning performed with low temporal resolution to reduce the radiation dose to the patient. The arterial input function (AIF) with high temporal resolution can be generated with a coarsely sampled AIF through a previously published method of AIF estimation. To increase the SNR of time-concentration curves (tissue curves), first, a region-of-interest is segmented into squares composed of 3 × 3 pixels in size. Subsequently, the PCA filtering combined with a fraction of residual information criterion is applied to all the segmented squares for further improvement of their SNRs. The proposed method was applied to each DCE-CT data set of a cohort of 14 patients at varying levels of down-sampling. The kinetic analyses using the modified Tofts’ model and singular value decomposition method, then, were carried out for each of the down-sampling schemes between the intervals from 2 to 15 s. The results were compared with analyses done with the measured data in high temporal resolution (i.e., original scanning frequency) as the reference. Results: The patients’ AIFs were estimated to high accuracy based on the 11 orthonormal bases of arterial impulse responses established in the previous paper. In addition, noise in the images was effectively reduced by using five principal components of the tissue curves for filtering. Kinetic analyses using the proposed method showed superior results compared to those with down-sampling alone; they were able to maintain the accuracy in the

  11. A breast-specific, negligible-dose scatter correction technique for dedicated cone-beam breast CT: a physics-based approach to improve Hounsfield Unit accuracy

    Science.gov (United States)

    Yang, Kai; Burkett, George, Jr.; Boone, John M.

    2014-11-01

    The purpose of this research was to develop a method to correct the cupping artifact caused from x-ray scattering and to achieve consistent Hounsfield Unit (HU) values of breast tissues for a dedicated breast CT (bCT) system. The use of a beam passing array (BPA) composed of parallel-holes has been previously proposed for scatter correction in various imaging applications. In this study, we first verified the efficacy and accuracy using BPA to measure the scatter signal on a cone-beam bCT system. A systematic scatter correction approach was then developed by modeling the scatter-to-primary ratio (SPR) in projection images acquired with and without BPA. To quantitatively evaluate the improved accuracy of HU values, different breast tissue-equivalent phantoms were scanned and radially averaged HU profiles through reconstructed planes were evaluated. The dependency of the correction method on object size and number of projections was studied. A simplified application of the proposed method on five clinical patient scans was performed to demonstrate efficacy. For the typical 10-18 cm breast diameters seen in the bCT application, the proposed method can effectively correct for the cupping artifact and reduce the variation of HU values of breast equivalent material from 150 to 40 HU. The measured HU values of 100% glandular tissue, 50/50 glandular/adipose tissue, and 100% adipose tissue were approximately 46, -35, and -94, respectively. It was found that only six BPA projections were necessary to accurately implement this method, and the additional dose requirement is less than 1% of the exam dose. The proposed method can effectively correct for the cupping artifact caused from x-ray scattering and retain consistent HU values of breast tissues.

  12. Diagnostic Accuracy of PET/CT-Guided Percutaneous Biopsies for Malignant Peripheral Nerve Sheath Tumors in Neurofibromatosis Type 1 Patients.

    Directory of Open Access Journals (Sweden)

    Mehdi Brahmi

    biopsy gave 25 accurate diagnoses and one false negative (BPNST with atypical cells on the biopsy and MPNST on the operated tumor, resulting in a diagnostic accuracy rate of 96%. This false negative case may be explained by the high heterogeneity of the tumor: benign areas were contiguous with the malignant ones and associated with inflammation.PET/CT-guided percutaneous biopsies are an effective and relatively non-traumatic procedure for diagnosis of NF1-related MPNST. It is the most reliable approach for early detection of MPNST.

  13. Is diagnostic accuracy for detecting pulmonary nodules in chest CT reduced after a long day of reading?

    Science.gov (United States)

    Krupinski, Elizabeth A.; Berbaum, Kevin S.; Caldwell, Robert; Schartz, Kevin M.

    2012-02-01

    Radiologists are reading more cases with more images, especially in CT and MRI and thus working longer hours than ever before. There have been concerns raised regarding fatigue and whether it impacts diagnostic accuracy. This study measured the impact of reader visual fatigue by assessing symptoms, visual strain via dark focus of accommodation, and diagnostic accuracy. Twenty radiologists and 20 radiology residents were given two diagnostic performance tests searching CT chest sequences for a solitary pulmonary nodule before (rested) and after (tired) a day of clinical reading. 10 cases used free search and navigation, and the other 100 cases used preset scrolling speed and duration. Subjects filled out the Swedish Occupational Fatigue Inventory (SOFI) and the oculomotor strain subscale of the Simulator Sickness Questionnaire (SSQ) before each session. Accuracy was measured using ROC techniques. Using Swensson's technique yields an ROC area = 0.86 rested vs. 0.83 tired, p (one-tailed) = 0.09. Using Swensson's LROC technique yields an area = 0.73 rested vs. 0.66 tired, p (one-tailed) = 0.09. Using Swensson's Loc Accuracy technique yields an area = 0.77 rested vs. 0.72 tired, p (one-tailed) = 0.13). Subjective measures of fatigue increased significantly from early to late reading. To date, the results support our findings with static images and detection of bone fractures. Radiologists at the end of a long work day experience greater levels of measurable visual fatigue or strain, contributing to a decrease in diagnostic accuracy. The decrease in accuracy was not as great however as with static images.

  14. Diagnostic accuracy of 64 multislice CT angiography in the assessment of coronary in-stent restenosis: A meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun Zhonghua [Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, Perth, WA (Australia)], E-mail: z.sun@curtin.edu.au; Almutairi, Abdulrahman Marzouq D. [Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, Perth, WA (Australia)

    2010-02-15

    Purpose: The aim of this study was to perform a meta-analysis of the diagnostic accuracy of 64-slice CT angiography for the detection of coronary in-stent restenosis in patients treated with coronary stents when compared to conventional coronary angiography. Materials and methods: A search of PUBMED/MEDLINE, ProQuest and Cochrane library databases for English literature was performed. Only studies comparing 64-slice CT angiography with conventional coronary angiography for the detection of coronary in-stent restenosis (more than 50% stenosis) were included for analysis. Sensitivity and specificity estimates pooled across studies were tested using a fixed effects model. Results: Fourteen studies met selection criteria for inclusion in the analysis. The mean value of assessable stents was 89%. Prevalence of in-stent restenosis following coronary stenting was 20% among these studies. Pooled estimates of the sensitivity and specificity of overall 64-slice CT angiography for the detection of coronary in-stent restenosis was 90% (95% CI: 86%, 94%) and 91% (95% CI: 90%, 93%), respectively, based on the evaluation of assessable stents. Diagnostic value of 64-slice CT angiography was found to decrease significantly when the analysis was performed with inclusion of nonassessable segments in five studies, with pooled sensitivity and specificity being 79% (95% CI: 68%, 88%) and 81% (95% CI: 77%, 84%). Stent diameter is the main factor affecting the diagnostic value of 64-slice CT angiography. Conclusion: Our results showed that 64-slice CT angiography has high diagnostic value (both sensitivity and specificity) for detection of coronary in-stent restenosis based on assessable segments when compared to conventional coronary angiography.

  15. A comparative study of the diagnostic accuracy on Waters view with CT scan in detecting midface fractures

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2006-08-01

    Full Text Available Background and Aim: In recent years, CT scan has become available as an alternative to conventional radiography. To date, the utility of Waters view in detecting midface fractures has been rarely evaluated. The aim of this study was to compare the diagnostic accuracy and reliability of Waters radiography with CT scan in detecting midface fractures. Materials and Methods: In this tests evaluation study, waters view and CT scan were performed for 42 patients with midface fracture admitted to maxillofacial surgery department of Shariati hospital. All images were observed and interpreted by an oral and maxillofacial radiologist and an oral and maxillofacial surgeon. Sensitivity, specificity and reliability for Waters view in detecting midface fractures were assessed by Cohen’s kappa test. Results: Sensitivity and specificity for Waters view in detection of midface fratures by the radiologist were 31.79% and 95.35% and by the surgeon were 29.59% and 93.75% respectively. The highest reliability in CT scan and Waters view (in nasal fractures by the radiologist was 66.67% and was 58.33% by the surgeon in buttress of zygoma. The highest agreement rate between the radiologist and the surgeon for CT scan was in zygomatic arch (78.95% and for Waters view was in nasal fracture (62.5%. Conclusion: Based on the results of this study, the specificity of Waters view is sufficient to diagnose fractures of lateral orbital wall, infraorbital rim, orbital floor, zygomatic arch, frontozygomatic suture, lateral wall of maxillary sinus and Lefort II fracture. The specificity is not sufficient to diagnose fractures of medial orbital wall and anterior, posterior and medial wall of maxillary sinus. Detection of these midface fractures needs other conventional radiographies or CT scan.

  16. Repositioning accuracy of cerebral fractionated stereotactic radiotherapy using CT scanning; Evaluation par tomodensitometrie du repositionnement en radiotherapie stereotaxique fractionnee cerebrale

    Energy Technology Data Exchange (ETDEWEB)

    Pasquier, D.; Dubus, F.; Castelain, B.; Delplanque, M.; Lartigau, E. [Centre O.-Lambret, Dept. Universitaire de Radiotherapie, 59 - Lille (France); Pasquier, D. [Centre Galilee, Polyclinique de la Louviere, 59 - Lille (France); Bernier, V.; Buchheit, I. [Centre Alexis-Vautrin, Dept. de Radiotherapie, 54 - Vandoeuvre-les-Nancy (France); Kerr, C.; Santoro, I. [Centre Val d' Aurelle, Dept. de Radiotherapie, 34 - Montpellier (France); Huchet, A.; Causse, N. [Hopital Saint-Andre, Dept. de Radiotherapie, 33 - Bordeaux (France); Dubus, F.; Castelain, B.; Delplanque, M.; Lartigau, E. [Lille-2 Univ., 59 (France)

    2009-09-15

    Purpose: To evaluate the accuracy of patient repositioning in fractionated cerebral stereotactic radiotherapy using a Brain Lab stereotactic cranial mask in conjunction with standard dental fixation. Patients and methods: Fifty planning and checking CT scans were performed in 25 patients. The check CT scan was performed before or after one of the three sessions of treatment. Co registration to the planning CT scan was used to assess alignment of the iso centre to the reference markers. The relative position of the P.T.V. with regard to iso centre allowed us to determine its total displacement (3-dimensional vector). Results: Mean iso centre translations ({+-} S.D.) taking into account direction were -0.01 {+-} 0.7, -0.2 {+-} 1.3 and 0.07 {+-} 0.5 mm in medio-lateral, cranio caudal and anteroposterior directions respectively. Mean rotations ({+-}S.D.) were -0.02 {+-} 0.6, -0.08 {+-} 0.3 and -0.1 {+-} 0.3 degree in medio-lateral, cranio caudal and anteroposterior axes respectively. Mean overall P.T.V. displacement was 1.8 {+-} 1.5 mm. P.T.V. displacement was smaller than 2 and 3 mm in 19/25 and 23/25 patients respectively. Conclusion: The accuracy of patient positioning using a stereotactic cranial mask system is similar to those reported in the literature and shows a satisfactory reproducibility with a standard dental fixation. (authors)

  17. The iPad as a mobile device for CT display and interpretation: diagnostic accuracy for identification of pulmonary embolism.

    Science.gov (United States)

    Johnson, Pamela T; Zimmerman, Stefan L; Heath, David; Eng, John; Horton, Karen M; Scott, William W; Fishman, Elliot K

    2012-08-01

    Recent software developments enable interactive, real-time axial, 2D and 3D CT display on an iPad by cloud computing from a server for remote rendering. The purpose of this study was to compare radiologists' interpretative performance on the iPad to interpretation on the conventional picture archive and communication system (PACS). Fifty de-identified contrast-enhanced CT exams performed for suspected pulmonary embolism were compiled as an educational tool to prepare our residents for night call. Two junior radiology attendings blindly interpreted the cases twice, one reader used the PACS first, and the other interpreted on the iPad first. After an interval of at least 2 weeks, the cases were reinterpreted in different order using the other display technique. Sensitivity, specificity, and accuracy for identification of pulmonary embolism were compared for each interpretation method. Pulmonary embolism was present in 25 patients, ranging from main pulmonary artery to subsegmental thrombi. Both readers interpreted 98 % of cases correctly regardless of display platform. There was no significant difference in sensitivity (98 vs 100 %, p = 1.0), specificity (98 vs 96 %, p = 1.0), or accuracy (98 vs 98 %, p = 1.0) for interpretation with the iPad vs the PACS, respectively. CT interpretation on an iPad enabled accurate identification of pulmonary embolism, equivalent to display on the PACS. This mobile device has the potential to expand radiologists' availability for consultation and expedite emergency patient management.

  18. Accuracy of Rhenium-188 SPECT/CT activity quantification for applications in radionuclide therapy using clinical reconstruction methods

    Science.gov (United States)

    Esquinas, Pedro L.; Uribe, Carlos F.; Gonzalez, M.; Rodríguez-Rodríguez, Cristina; Häfeli, Urs O.; Celler, Anna

    2017-08-01

    The main applications of 188Re in radionuclide therapies include trans-arterial liver radioembolization and palliation of painful bone-metastases. In order to optimize 188Re therapies, the accurate determination of radiation dose delivered to tumors and organs at risk is required. Single photon emission computed tomography (SPECT) can be used to perform such dosimetry calculations. However, the accuracy of dosimetry estimates strongly depends on the accuracy of activity quantification in 188Re images. In this study, we performed a series of phantom experiments aiming to investigate the accuracy of activity quantification for 188Re SPECT using high-energy and medium-energy collimators. Objects of different shapes and sizes were scanned in Air, non-radioactive water (Cold-water) and water with activity (Hot-water). The ordered subset expectation maximization algorithm with clinically available corrections (CT-based attenuation, triple-energy window (TEW) scatter and resolution recovery was used). For high activities, the dead-time corrections were applied. The accuracy of activity quantification was evaluated using the ratio of the reconstructed activity in each object to this object’s true activity. Each object’s activity was determined with three segmentation methods: a 1% fixed threshold (for cold background), a 40% fixed threshold and a CT-based segmentation. Additionally, the activity recovered in the entire phantom, as well as the average activity concentration of the phantom background were compared to their true values. Finally, Monte-Carlo simulations of a commercial γ -camera were performed to investigate the accuracy of the TEW method. Good quantification accuracy (errors  activity concentration and for objects in cold background segmented with a 1% threshold. However, the accuracy of activity quantification for objects segmented with 40% threshold or CT-based methods decreased (errors  >15%), mostly due to partial-volume effects. The Monte

  19. Simulation study on potential accuracy gains from dual energy CT tissue segmentation for low-energy brachytherapy Monte Carlo dose calculations

    Science.gov (United States)

    Landry, Guillaume; Granton, Patrick V.; Reniers, Brigitte; Öllers, Michel C.; Beaulieu, Luc; Wildberger, Joachim E.; Verhaegen, Frank

    2011-10-01

    This work compares Monte Carlo (MC) dose calculations for 125I and 103Pd low-dose rate (LDR) brachytherapy sources performed in virtual phantoms containing a series of human soft tissues of interest for brachytherapy. The geometries are segmented (tissue type and density assignment) based on simulated single energy computed tomography (SECT) and dual energy (DECT) images, as well as the all-water TG-43 approach. Accuracy is evaluated by comparison to a reference MC dose calculation performed in the same phantoms, where each voxel's material properties are assigned with exactly known values. The objective is to assess potential dose calculation accuracy gains from DECT. A CT imaging simulation package, ImaSim, is used to generate CT images of calibration and dose calculation phantoms at 80, 120, and 140 kVp. From the high and low energy images electron density ρe and atomic number Z are obtained using a DECT algorithm. Following a correction derived from scans of the calibration phantom, accuracy on Z and ρe of ±1% is obtained for all soft tissues with atomic number Z in [6,8] except lung. GEANT4 MC dose calculations based on DECT segmentation agreed with the reference within ±4% for 103Pd, the most sensitive source to tissue misassignments. SECT segmentation with three tissue bins as well as the TG-43 approach showed inferior accuracy with errors of up to 20%. Using seven tissue bins in our SECT segmentation brought errors within ±10% for 103Pd. In general 125I dose calculations showed higher accuracy than 103Pd. Simulated image noise was found to decrease DECT accuracy by 3-4%. Our findings suggest that DECT-based segmentation yields improved accuracy when compared to SECT segmentation with seven tissue bins in LDR brachytherapy dose calculation for the specific case of our non-anthropomorphic phantom. The validity of our conclusions for clinical geometry as well as the importance of image noise in the tissue segmentation procedure deserves further

  20. Simulation study on potential accuracy gains from dual energy CT tissue segmentation for low-energy brachytherapy Monte Carlo dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Guillaume; Granton, Patrick V; Reniers, Brigitte; Oellers, Michel C; Verhaegen, Frank [Department of Radiation Oncology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Beaulieu, Luc [Departement de Radio-Oncologie et Centre de Recherche en Cancerologie, Universite Laval, CHUQ Pavillon L' Hotel-Dieu de Quebec, Quebec G1R 2J6 (Canada); Wildberger, Joachim E [Department of Radiology, Maastricht University Medical Center, P. Debijelaan 25, 6229 HX Maastricht (Netherlands)

    2011-10-07

    This work compares Monte Carlo (MC) dose calculations for {sup 125}I and {sup 103}Pd low-dose rate (LDR) brachytherapy sources performed in virtual phantoms containing a series of human soft tissues of interest for brachytherapy. The geometries are segmented (tissue type and density assignment) based on simulated single energy computed tomography (SECT) and dual energy (DECT) images, as well as the all-water TG-43 approach. Accuracy is evaluated by comparison to a reference MC dose calculation performed in the same phantoms, where each voxel's material properties are assigned with exactly known values. The objective is to assess potential dose calculation accuracy gains from DECT. A CT imaging simulation package, ImaSim, is used to generate CT images of calibration and dose calculation phantoms at 80, 120, and 140 kVp. From the high and low energy images electron density {rho}{sub e} and atomic number Z are obtained using a DECT algorithm. Following a correction derived from scans of the calibration phantom, accuracy on Z and {rho}{sub e} of {+-}1% is obtained for all soft tissues with atomic number Z in [6,8] except lung. GEANT4 MC dose calculations based on DECT segmentation agreed with the reference within {+-}4% for {sup 103}Pd, the most sensitive source to tissue misassignments. SECT segmentation with three tissue bins as well as the TG-43 approach showed inferior accuracy with errors of up to 20%. Using seven tissue bins in our SECT segmentation brought errors within {+-}10% for {sup 103}Pd. In general {sup 125}I dose calculations showed higher accuracy than {sup 103}Pd. Simulated image noise was found to decrease DECT accuracy by 3-4%. Our findings suggest that DECT-based segmentation yields improved accuracy when compared to SECT segmentation with seven tissue bins in LDR brachytherapy dose calculation for the specific case of our non-anthropomorphic phantom. The validity of our conclusions for clinical geometry as well as the importance of image noise

  1. Simulation study on potential accuracy gains from dual energy CT tissue segmentation for low-energy brachytherapy Monte Carlo dose calculations.

    Science.gov (United States)

    Landry, Guillaume; Granton, Patrick V; Reniers, Brigitte; Ollers, Michel C; Beaulieu, Luc; Wildberger, Joachim E; Verhaegen, Frank

    2011-10-07

    This work compares Monte Carlo (MC) dose calculations for (125)I and (103)Pd low-dose rate (LDR) brachytherapy sources performed in virtual phantoms containing a series of human soft tissues of interest for brachytherapy. The geometries are segmented (tissue type and density assignment) based on simulated single energy computed tomography (SECT) and dual energy (DECT) images, as well as the all-water TG-43 approach. Accuracy is evaluated by comparison to a reference MC dose calculation performed in the same phantoms, where each voxel's material properties are assigned with exactly known values. The objective is to assess potential dose calculation accuracy gains from DECT. A CT imaging simulation package, ImaSim, is used to generate CT images of calibration and dose calculation phantoms at 80, 120, and 140 kVp. From the high and low energy images electron density ρ(e) and atomic number Z are obtained using a DECT algorithm. Following a correction derived from scans of the calibration phantom, accuracy on Z and ρ(e) of ±1% is obtained for all soft tissues with atomic number Z ∊ [6,8] except lung. GEANT4 MC dose calculations based on DECT segmentation agreed with the reference within ±4% for (103)Pd, the most sensitive source to tissue misassignments. SECT segmentation with three tissue bins as well as the TG-43 approach showed inferior accuracy with errors of up to 20%. Using seven tissue bins in our SECT segmentation brought errors within ±10% for (103)Pd. In general (125)I dose calculations showed higher accuracy than (103)Pd. Simulated image noise was found to decrease DECT accuracy by 3-4%. Our findings suggest that DECT-based segmentation yields improved accuracy when compared to SECT segmentation with seven tissue bins in LDR brachytherapy dose calculation for the specific case of our non-anthropomorphic phantom. The validity of our conclusions for clinical geometry as well as the importance of image noise in the tissue segmentation procedure deserves

  2. 千伏级 CBCT 图像 CT 值校正及在放疗剂量计算中应用%Investigation of CT numbers correction of kilo-voltage cone-beam CT images for accurate dose calculation

    Institute of Scientific and Technical Information of China (English)

    王雪桃; 柏森; 李光俊; 蒋晓芹; 苏晨; 李衍龙; 朱智慧

    2015-01-01

    目的:研究千伏级CBCT图像CT值校正方法,提高其用于剂量计算的准确性。方法以扇形束计划 CT 作为先验信息,将 CBCT 与计划 CT 图像进行刚性配准,通过将 CBCT 与计划 CT 图像相减得到 CBCT 散射背景估计,对散射背景进行低通滤波处理,最后将原始 CBCT 图像减去滤波后的散射背景得到校正的 CBCT 图像。对 Catphan600模体和4例盆腔恶性肿瘤患者的 CBCT 图像进行校正,配对 t 检验校正前后 CBCT 与计划 CT 的差异,评估校正后的 CBCT 图像质量并分析用于剂量计算的准确性。结果经 CT 值校正后 CBCT 图像伪影明显减少,空气、脂肪、肌肉、股骨头的平均值校正前与计划 CT 分别相差232、89、29、66 HU,而校正后平均值差别缩小至5 HU 内(P=0??39、0??66、0??59、1??00)。校正后 CBCT 图像用于剂量计算误差在2%内。结论校正后的 CBCT 图像 CT 值与计划 CTCT 值相似,用于剂量计算可得到准确的结果。%Objective To study CT numbers correction of kilo?voltage cone?beam CT (KV?CBCT) images for dose calculation. Method Aligning the CBCT images with plan CT images, then obtain the background scatter by subtracting CT images from CBCT images. The background scatter is then processed by low?pass filter. The final CBCT images are acquired by subtracting the background scatter from the raw CBCT. KV?CBCT images of Catphan600 phantom and four patients with pelvic tumors were obtained with the linac?integrated CBCT system. The CBCT images were modified to correct the CT numbers. Finally, compare HU numbers between corrected CBCT and planning CT by paired T test. Evaluate the image quality and accuracy of dose calculation of the modified CBCT images. Results The proposed method reduces the artifacts of CBCT images significantly. The differences of CT numbers were 232 HU, 89 HU, 29 HU and 66 HU for air, fat, muscle and femoral head between CT and CBCT

  3. Sensitivity and accuracy of volumetry of pulmonary nodules on low-dose 16- and 64-row multi-detector CT : an anthropomorphic phantom study

    NARCIS (Netherlands)

    Xie, X.; Zhao, Yingru; Snijder, R.A.; van Ooijen, P.M.; de Jong, P.A.; Oudkerk, M.; de Bock, G.H.; Vliegenthart, R.; Greuter, M.J.

    2013-01-01

    To assess the sensitivity of detection and accuracy of volumetry by manual and semi-automated quantification of artificial pulmonary nodules in an anthropomorphic thoracic phantom on low-dose CT. Fifteen artificial spherical nodules (diameter 3, 5, 8, 10 and 12 mm; CT densities -800, -630 and +100 H

  4. Effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies

    Science.gov (United States)

    Murase, Kenya; Nanjo, Takafumi; Satoshi, Ii; Miyazaki, Shohei; Hirata, Masaaki; Sugawara, Yoshifumi; Kudo, Masayuki; Sasaki, Kousuke; Mochizuki, Teruhito

    2005-11-01

    The purpose of this study was to investigate the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using multi-detector row CT (MDCT). Following the standard CT perfusion study protocol, continuous (cine) scans (1 s/rotation × 60 s) consisting of four 5 mm thick contiguous slices were performed using an MDCT scanner with a tube voltage of 80 kVp and a tube current of 200 mA. We generated the simulated images with tube currents of 50 mA, 100 mA and 150 mA by adding the corresponding noise to the raw scan data of the original image acquired above using a noise simulation tool. From the original and simulated images, we generated the functional images of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) in seven patients with cerebrovascular disease, and compared the correlation coefficients (CCs) between the perfusion parameter values obtained from the original and simulated images. The coefficients of variation (CVs) in the white matter were also compared. The CC values deteriorated with decreasing tube current. There was a significant difference between 50 mA and 100 mA for all perfusion parameters. The CV values increased with decreasing tube current. There were significant differences between 50 mA and 100 mA and between 100 mA and 150 mA for CBF. For CBV and MTT, there was also a significant difference between 150 mA and 200 mA. This study will be useful for understanding the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using MDCT, and for selecting the tube current.

  5. How far can the radiation dose be lowered in head CT with iterative reconstruction? Analysis of imaging quality and diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tung-Hsin; Sun, Jing-Yi [National Yang-Ming University, Department of Biomedical Imaging and Radiological Sciences, Taipei (China); Hung, Sheng-Che; Lin, Chung-Jung; Chiu, Chen Fen; Liu, Min-Jsuan; Teng, Michael Mu Huo; Guo, Wan-Yuo; Chang, Cheng-Yen [Taipei Veterans General Hospital, Department of Radiology, Taipei (China); National Yang-Ming University, School of Medicine, Taipei (China); Lin, Chung-Hsien [National Taiwan University, Graduate Institute of Epidemiology and Preventive Medicine, Taipei (China)

    2013-09-15

    To evaluate the imaging quality of head CT at lowered radiation dose by combining filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Experimental group A (n = 66) underwent CT with 43 % tube current reduction, and group B (n = 58) received an equivalent reduced dose by lowering the tube voltage. An age- and sex-matched control group (n = 72) receiving the conventional radiation dose was retrospectively collected. Imaging for the control group was reconstructed by FBP only, while images for groups A and B were reconstructed by FBP and IR. The signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), sharpness, number of infarcts and severity of subcortical arteriosclerotic encephalopathy (SAE) were compared to assess imaging quality and diagnostic accuracy. There were no significant differences in SNRs and CNRs between group A and the control group. There were significantly decreased SNRs and increased CNRs in group B. Image sharpness decreased in both groups. Correlations between detected infarcts and severity of SAE across FBP and IR were high (r = 0.73-0.93). Head diameter was the only significant factor inversely correlated with infratentorial imaging quality. Head CT with 43 % reduced tube current reconstructed by IR provides diagnostic imaging quality for outpatient management. (orig.)

  6. Improving the accuracy of microelectrode recording in deep brain stimulation surgery with intraoperative CT.

    Science.gov (United States)

    Kochanski, Ryan B; Pal, Gian; Bus, Sander; Metman, Leo Verhagen; Sani, Sepehr

    2017-06-01

    Microelectrode recording (MER) is used to confirm electrophysiological signals within intended anatomic targets during deep brain stimulation (DBS) surgery. We describe a novel technique called intraoperative CT-guided extrapolation (iCTE) to predict the intended microelectrode trajectory and, if necessary, make corrections in real-time before dural opening. Prior to dural opening, a guide tube was inserted through the headstage and rested on dura. Intraoperative CT (iCT) was obtained, and a trajectory was extrapolated along the path of the guide tube to target depth using targeting software. The coordinates were recorded and compared to initial plan coordinates. If needed, adjustments were made using the headstage to correct for error. The guide tube was then inserted and MER ensued. At target, iCT was performed and microelectrode tip coordinates were compared with planned/adjusted track coordinates. Radial error between MER track and planned/adjusted track was calculated. For comparison, MER track error prior to the iCTE technique was assessed retrospectively in patients who underwent MER using iCT, whereby iCT was performed following completion of the first MER track. Forty-seven MER tracks were analyzed prior to iCTE (pre-iCTE), and 90 tracks were performed using the iCTE technique. There was no difference between radial error of pre-iCTE MER track and planned trajectory (2.1±0.12mm) compared to iCTE predicted trajectory and planned trajectory (1.76±0.13mm, p>0.05). iCTE was used to make trajectory adjustments which reduced radial error between the newly corrected and final microelectrode tip coordinates to 0.84±0.08mm (preliability was also tested using a second blinded measurement reviewer which showed no difference between predicted and planned MER track error (p=0.53). iCTE can predict and reduce trajectory error for microelectrode placement compared with the traditional use of iCT post MER. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Accuracy of the AAST organ injury scale for CT evaluation of traumatic liver and spleen injuries

    Directory of Open Access Journals (Sweden)

    Homann Georg

    2014-02-01

    Full Text Available 【Abstract】Objective: Detection of abdominal injury is a very important component in trauma management, so a precise assessment of liver and spleen injuries including their severity degree is necessary. There is a good case to believe that in emergency situations the radiologists’ performance may profit from a systematic approach using established scoring systems. Score systems as the organ injury scale (OIS drawn up by the American Association for the Surgery of Trauma are a valuable guidance for objective trauma assessment. Aim of this study was to evaluate retrospectively whether a structured approach using the OIS may help improve trauma assessment. Methods: Fifty-three patients, 38 male and 15 female who underwent CT and laparotomy after abdominal trauma were included in this study. The laparotomy was performed by experienced surgeons with a minimum experience of 6 years. While the original CT reports were written by different radiologists with a minimum experience of 3 years, and then a radiologist with experience of 4 years reviewed the same original CT pictures, resulting in the structured report. Both the original and structured CT results on liver and spleen injuries were transferred into OIS grades. Finally, the initial and structured CT results were compared with the intraoperative findings gathered from the surgery report. Results: Regarding the original CT report we found a mean divergence of 0.68±0.8 (r=0.45 to the OIS finding in the surgery report for liver injuries (0.69±1.17 for spleen injuries; r=0.69. In comparison with the structured approach, where we detected a divergence of 0.8±0.68; r=0.63 (0.47±0.77 for spleen injuries; r=0.91, there was no significant difference. However we detected a lower rate of over-diagnosis in structured approaches. Conclusion: Our study shows that a structured approach to triage abdominal trauma using an imaging check- list does not lead to a significantly higher detection rate, but a

  8. Software-based hybrid perfusion SPECT/CT provides diagnostic accuracy when other pulmonary embolism imaging is indeterminate

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nishant; Xie, Karen; Mar, Winnie; Anderson, Thomas M.; Carney, Benjamin; Mehta, Nikhil; Machado, Roberto; Blend, Michael J.; Lu, Yang [University of Illinois Hospital and Health Sciences System, Chicago (Korea, Republic of)

    2015-12-15

    To investigate the diagnostic performance of perfusion single-photon emission computed tomography/computed tomography (Q-SPECT/CT) in patients suspected to have pulmonary embolism (PE) but with indeterminate computed tomographic pulmonary angiography (CTPA) or planar ventilation/perfusion (V/Q) scans. This retrospective study included two groups of patients. Group I consisted of 49 patients with nondiagnostic CTPA. These 49 patients underwent subsequent V/Q scans. Further Q-SPECTs were obtained in patients with indeterminate planar images and fused with existing CTPA. Group II consisted of 182 non-CTPA patients with indeterminate V/Q scans. These 182 patients underwent further Q-SPECT and separate noncontrast low-dose CT chest. Fusion Q-SPECT/CT scans were obtained through FDA-approved software and interpreted according to published criteria as positive, negative, or indeterminate for PE. Upon retrospective analyses, the final diagnosis was made using composite reference standards including all available clinical and imaging information for at least 6-month follow-up. In group I patients, 1 was positive, 24 were negative, and another 24 (49 %, 24/49) were indeterminate. In the subsequent 24 Q-SPECT/CTPAs, 4 were positive, 19 were negative, and 1 was indeterminate (4.2 %, 1/24). In group II patients, 9 (4.9 %, 9/182) were indeterminate, 33 were positive, and 140 were negative. The combined nondiagnostic rate for Q-SPECT/CT was only 4.9 % (10/206). There was six false-negative and one false-positive Q-SPECT/CT examinations. The sensitivity, specificity, and positive and negative predictive value of Q-SPECT/CT were 85.7 % (36/42), 99.4 % (153/154), 97.3 % (36/37) and 96.2 % (153/159), respectively. Q-SPECT/CT improves the diagnostic rate with promising accuracy in diagnosing PE that yields a satisfactory clinical verdict, especially when the CTPA and planar V/Q scan are indeterminate.

  9. SU-E-I-37: A Renewed Look at CT Numbers as Encountered in the Diagnostic and Therapeutic Range.

    Science.gov (United States)

    Fredriksson, J; Goodenough, D; Healy, A; Kristbjornsson, A; Kristinsson, S; Levy, J; Olafsdottir, H

    2012-06-01

    With the development of RT treatment planning systems that use the relationship between CT number and Electron Density (ED), rather than the Linear Attenuation Coefficient (LAC) of a given material, a number of authors have pointed out the divergence between the linearity of CT numbers vs. LAC in the diagnostic range compared to the relationship between the CT number and ED. This paper will review the differences and similarities, and describe a new set of phantom test objects and automated software that can be used to automatically assess both scales. In particular the relative importance of atomic number (Z) and the relative impact of Coherent vs. Incoherent effects at high Z levels will be evaluated. A newly developed phantom (Catphan® 700) has an expanded set of sensitometric samples of known density, electron density, and chemical composition (Z effective). CT scans of the phantom were obtained at various energies (kVp) and the measured CT numbers were compared to the known physical characteristics mentioned above. Regressions between measured CT numbers, linear attenuation coefficients (with and without coherent scattering effects), and electron density for the materials were performed. Effects of different materials and the inclusion of coherent scattering on linearity scale and effective energy were established. The linearity scale and effective energy are shown to be dependent on the selection of materials scanned and the inclusion/exclusion of coherent scattering effects in the linear attenuation coefficients. Electron density deviates significantly from a linear relationship with CT number. Caveats accompanying high Z materials are reinforced regarding application to the RT relationship between CT number and electron density. Interesting results were obtained for the influence of coherent vs. incoherent scattering, which appears to be important as the number of slices and scanning volume increases in CT. Funding provided by The Phantom Laboratory

  10. Diagnostic accuracy and complication rate of CT-guided fine needle aspiration biopsy of lung lesions: A study based on the experience of the cytopathologist

    Energy Technology Data Exchange (ETDEWEB)

    Massimiliano Priola, Adriano; Priola, Sandro Massimo; Cataldi, Aldo; Paze, Francesco (Dept. of Diagnostic and Interventional Radiology, Univ. of Turin, S. Luigi Gonzaga Hospital, Turin (Italy)), e-mail: adriano.priola@inwind.it; Di Franco, Marisa (Dept. of Pharmacology, S. Luigi Gonzaga Hospital, Orbassano, Turin (Italy)); Marci, Valerio (Dept. of Pathology, S. Luigi Gonzaga Hospital, Orbassano, Turin (Italy)); Berruti, Alfredo (Dept. of Oncology, S. Luigi Gonzaga Hospital, Orbassano, Turin (Italy))

    2010-06-15

    Background: CT-guided transthoracic needle biopsy is a well-established technique for the diagnosis of focal lung lesions. Fine needle aspiration biopsy (FNAB) requires the presence of a cytopathologist on-site to assess the adequacy of samples. For this reason FNAB is less and less used, and core biopsy is the first-line procedure when an experienced cytopathologist is not immediately available. Purpose: To evaluate the accuracy and complication rate of CT-guided FNAB of lung lesions according to the experience of the cytopathologist on-site. Material and Methods: A total of 321 consecutive biopsies were considered. Immediate cytological assessment was performed by an experienced cytopathologist for the first 165 procedures (group A) and by two training pathologists for the remaining 156 biopsies (group B). At the time of FNAB the pathologist assigned a semiquantitative score (0-3) to each specimen to assess its diagnostic quality. All variables between the two groups were analyzed by chi-square and Student's t test. A P value <0.05 was considered statistically significant. Results: For all procedures, overall diagnostic accuracy was 80% for cytology alone, with no statistical difference between the two groups for diagnostic accuracy and sample score assigned. In all, 75% of the cytological samples (75% group A, 74% group B) obtained a higher score with a specific diagnosis of histotype. A post biopsy pneumothorax was detected in 27% of biopsies (25% group A, 28% group B). Thirteen patients (4.0%) required chest tube insertion for treatment. For all cases, the pneumothorax rate was significantly affected by the number of samples obtained (P=0.02), but not by the pleural punctures (P=0.15). There was no statistically significant difference between the two groups concerning the number of needle passes and complication rate (P>0.05). Conclusion: The efficacy and safety of CT-guided FNAB is not significantly affected by the training level of the cytopathologist

  11. Accuracy of automated software-guided detection of significant coronary artery stenosis by CT angiography: comparison with invasive catheterisation

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Katharina; Uder, Michael [University of Erlangen, Department of Radiology, Erlangen (Germany); Achenbach, Stephan; Petit, Isabel; Daniel, Werner G.; Pflederer, Tobias [University of Erlangen, Department of Internal Medicine 2 (Cardiology), Erlangen (Germany)

    2013-05-15

    True automated detection of coronary artery stenoses might be useful whenever expert evaluation is not available, or as a ''second reader'' to enhance diagnostic confidence. We evaluated the accuracy of a PC-based stenosis detection tool alone and combined with expert interpretation. One hundred coronary CT angiography datasets were evaluated with the automated software alone, by manual interpretation (axial images, multiplanar reformations and maximum intensity projections in free double-oblique planes), and by expert interpretation aware of the automated findings. Stenoses {>=} 50 % were noted per-vessel and per-patient, and compared with invasive angiography. Automated post-processing was successful in 90 % of patients (88 % of vessels). When excluding uninterpretable datasets, per-patient sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 89 %, 79 %, 74 % and 92 % (per-vessel: 82 %, 85 %, 48 % and 96 %). All 100 datasets were evaluable by expert interpretation. Per-patient sensitivity, specificity, PPV and NPV were 95 %, 95 %, 93 % and 97 % (per-vessel: 89 %,98 %, 88 % and 98 %). Knowing the results of automated interpretation did not improve the performance of expert readers. Automated off-line post-processing of coronary CT angiography shows adequate sensitivity, but relatively low specificity in coronary stenosis detection. It does not increase accuracy of expert interpretation. Failure of post-processing in 10 % of all patients necessitates additional manual image work-up. (orig.)

  12. Detection of pulmonary metastases with pathological correlation: effect of breathing on the accuracy of spiral CT. Editor`s note

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, F.V. [Abdominal Imaging Section, Department of Radiology, University of California, San Francisco, CA (United States); Cohen, M.D. [Department of Radiology, Riley Hospital for Children, Indianapolis, IN (United States); Waters, D.J. [Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN (United States); Davis, M.M. [Department of Pathology, Riley Hospital for Children, Indianapolis, IN (United States); Karmazyn, B. [Department of Radiology, Riley Hospital for Children, Indianapolis, IN (United States); Gonin, R. [Division of Biostatistics, Department of Medicine, Riley Hospital for Children, Indianapolis, IN (United States); Hanna, M.P. [Division of Biostatistics, Department of Medicine, Riley Hospital for Children, Indianapolis, IN (United States)

    1997-07-01

    Background. CT of the chest for suspected pulmonary metastases in adults is generally performed using a breath-hold technique. The results may not be applicable to young children in whom breath-holding may be impossible. Objective. Determine the effect of breathing on the accuracy of pulmonary metastasis detection by spiral CT (SCT). Materials and methods. Prior to euthanasia four anesthetized dogs with metastatic osteosarcoma underwent SCT with a collimation of 5 mm and a pitch of 2, during both induced breath-hold and normal quiet breathing. Images were reconstructed as contiguous 5-mm slices. Macroscopically evident metastases were noted at postmortem. Hard-copy SCT images were reviewed by ten radiologists, each of whom circled all suspected metastases. SCT images were compared with postmortem results to determine true and false positives. Results. The pathologist identified 132 macroscopically evident pulmonary metastases. For metastasis detection, there was no significant difference between breath-hold SCT and breathing SCT. Conclusion. In our animal model, SCT can be performed during normal resting breathing without significant loss of accuracy in the detection of pulmonary metastases. (orig.). With 3 tabs.

  13. Advanced Primary Epithelial Ovarian and Peritoneal Carcinoma-Does Diagnostic Accuracy of Preoperative CT Scan for Detection of Peritoneal Metastatic Sites Reflect into Prediction of Suboptimal Debulking? A Prospective Study.

    Science.gov (United States)

    Bagul, Kiran; Vijaykumar, D K; Rajanbabu, Anupama; Antony, Mitchelle Aline; Ranganathan, Venkatesan

    2017-06-01

    Ovarian cancer is the seventh most common cancer in females worldwide. Optimal debulking is the standard treatment but possible only in 30-85% of advanced stages. Knowing exactly the disease extent preoperatively may predict suboptimal debulking. We analyzed diagnostic accuracy of preoperative CT scan in disease mapping and prediction of suboptimal debulking in a prospective observational study from March 2013 to May 2015 in a tertiary hospital. Adults below the age of 75 years with ECOG PS-0, 1, 2, clinically/radiologically newly diagnosed stage IIIc epithelial ovarian (EOC), and primary peritoneal carcinoma (PPC) were included. Neoadjuvant chemotherapy recipients were excluded. Preoperative multidetector CT (MDCT) scan showing deposits at 19 predetermined abdominopelvic sites were compared with the same sites seen at laparotomy and corresponding accuracies of CT scan calculated. Primary debulking surgery was done to achieve debulking to nil or less than 1-cm residual disease. Stepwise logistic regression models were used to determine the frequent suboptimal debulking sites and the predictive performance of the clinical and CT scan findings. A total of 36 patients were enrolled. The optimal debulking rate was 50%. The CT scan could detect the disease-bearing sites with overall sensitivity of 68.29%, specificity of 89%, accuracy of 78.07%, and positive and negative predictive values of 99 and 50.1%, respectively. Upon multivariate analysis, bowel mesentery (p 0.011) and omental extension (p 0.025) were associated with suboptimal debulking. CT scan accuracy at these sites (predictive performance) was 86.1%. We identified small bowel mesentery and omental extension (to spleen/stomach/colon) as sites associated with suboptimal debulking. MDCT accurately depicts peritoneal metastases, although sensitivity is reduced in certain areas of significance for optimal debulking. Further validation with more number of patients is warranted.

  14. Accuracy of internal mammary lymph node localization using lymphoscintigraphy, sonography and CT.

    NARCIS (Netherlands)

    Saarnak, A.E.; Hurkmans, C.W.; Pieters, B.R.; Valdes Olmos, R.A.; Hart, A.A.M.; Schultze Kool, L.J.; Muller, S.H.

    2002-01-01

    Background and PURPOSE: An accurate internal mammary (IM) lymph node localization technique is required for proper irradiation of the IM lymph nodes in breast cancer patients. In this study the measurement accuracy of three techniques for direct or indirect localization of the IM nodes was

  15. Accuracy of CT cerebral perfusion in predicting infarct in the emergency department: lesion characterization on CT perfusion based on commercially available software.

    Science.gov (United States)

    Ho, Chang Y; Hussain, Sajjad; Alam, Tariq; Ahmad, Iftikhar; Wu, Isaac C; O'Neill, Darren P

    2013-06-01

    This study aims to assess the diagnostic accuracy of a single vendor commercially available CT perfusion (CTP) software in predicting stroke. A retrospective analysis on patients presenting with stroke-like symptoms within 6 h with CTP and diffusion-weighted imaging (DWI) was performed. Lesion maps, which overlays areas of computer-detected abnormally elevated mean transit time (MTT) and decreased cerebral blood volume (CBV), were assessed from a commercially available software package and compared to qualitative interpretation of color maps. Using DWI as the gold standard, parameters of diagnostic accuracy were calculated. Point biserial correlation was performed to assess for relationship of lesion size to a true positive result. Sixty-five patients (41 females and 24 males, age range 22-92 years, mean 57) were included in the study. Twenty-two (34 %) had infarcts on DWI. Sensitivity (83 vs. 70 %), specificity (21 vs. 69 %), negative predictive value (77 vs. 84 %), and positive predictive value (29 vs. 50 %) for lesion maps were contrasted to qualitative interpretation of perfusion color maps, respectively. By using the lesion maps to exclude lesions detected qualitatively on color maps, specificity improved (80 %). Point biserial correlation for computer-generated lesions (R pb = 0.46, p perfusion color map assessment, the lesion maps can help improve specificity.

  16. Diagnostic accuracy of {sup 18}F-FDG PET/CT compared with that of contrast-enhanced MRI of the breast at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Magometschnigg, Heinrich F.; Baltzer, Pascal A.; Fueger, Barbara; Helbich, Thomas H.; Weber, Michael [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Vienna (Austria); Karanikas, Georgios [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Vienna (Austria); Dubsky, Peter [Medical University of Vienna, Department of Surgery, Vienna (Austria); Rudas, Margaretha [Medical University of Vienna, Department of Pathology, Vienna (Austria); Pinker, Katja [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Vienna (Austria); Molecular Imaging and Therapy Service, Memorial Sloan Kettering Cancer Center, New York (United States)

    2015-10-15

    To compare the diagnostic accuracy of prone {sup 18}F-FDG PET/CT with that of contrast-enhanced MRI (CE-MRI) at 3 T in suspicious breast lesions. To evaluate the influence of tumour size on diagnostic accuracy and the use of maximum standardized uptake value (SUV{sub MAX}) thresholds to differentiate malignant from benign breast lesions. A total of 172 consecutive patients with an imaging abnormality were included in this IRB-approved prospective study. All patients underwent {sup 18}F-FDG PET/CT and CE-MRI of the breast at 3 T in the prone position. Two reader teams independently evaluated the likelihood of malignancy as determined by {sup 18}F-FDG PET/CT and CE-MRI independently. {sup 18}F-FDG PET/CT data were qualitatively evaluated by visual interpretation. Quantitative assessment was performed by calculation of SUV{sub MAX}. Sensitivity, specificity, diagnostic accuracy, area under the curve and interreader agreement were calculated for all lesions and for lesions <10 mm. Histopathology was used as the standard of reference. There were 132 malignant and 40 benign lesions; 23 lesions (13.4 %) were <10 mm. Both {sup 18}F-FDG PET/CT and CE-MRI achieved an overall diagnostic accuracy of 93 %. There were no significant differences in sensitivity (p = 0.125), specificity (p = 0.344) or diagnostic accuracy (p = 1). For lesions <10 mm, diagnostic accuracy deteriorated to 91 % with both {sup 18}F-FDG PET/CT and CE-MRI. Although no significant difference was found for lesions <10 mm, CE-MRI at 3 T seemed to be more sensitive but less specific than {sup 18}F-FDG PET/CT. Interreader agreement was excellent (κ = 0.85 and κ = 0.92). SUV{sub MAX} threshold was not helpful in differentiating benign from malignant lesions. {sup 18}F-FDG PET/CT and CE-MRI at 3 T showed equal diagnostic accuracies in breast cancer diagnosis. For lesions <10 mm, diagnostic accuracy deteriorated, but was equal for {sup 18}F-FDG PET/CT and CE-MRI at 3 T. For lesions <10 mm, CE-MRI at 3 T seemed

  17. Prediction of nodal involvement in primary rectal carcinoma without invasion to pelvic structures: accuracy of preoperative CT, MR, and DWIBS assessments relative to histopathologic findings.

    Directory of Open Access Journals (Sweden)

    Jun Zhou

    Full Text Available OBJECTIVE: To investigate the accuracy of preoperative computed tomography (CT, magnetic resonance (MR imaging and diffusion-weighted imaging with background body signal suppression (DWIBS in the prediction of nodal involvement in primary rectal carcinoma patients in the absence of tumor invasion into pelvic structures. METHODS AND MATERIALS: Fifty-two subjects with primary rectal cancer were preoperatively assessed by CT and MRI at 1.5 T with a phased-array coil. Preoperative lymph node staging with imaging modalities (CT, MRI, and DWIBS were compared with the final histological findings. RESULTS: The accuracy of CT, MRI, and DWIBS were 57.7%, 63.5%, and 40.4%. The accuracy of DWIBS with higher sensitivity and negative predictive value for evaluating primary rectal cancer patients was lower than that of CT and MRI. Nodal staging agreement between imaging and pathology was fairly strong for CT and MRI (Kappa value = 0.331 and 0.348, P<0.01 but was relatively weaker for DWIBS (Kappa value = 0.174, P<0.05. The accuracy was 57.7% and 59.6%, respectively, for CT and MRI when the lymph node border information was used as the criteria, and was 57.7% and 61.5%, respectively, for enhanced CT and MRI when the lymph node enhancement pattern was used as the criteria. CONCLUSION: MRI is more accurate than CT in predicting nodal involvement in primary rectal carcinoma patients in the absence of tumor invasion into pelvic structures. DWIBS has a great diagnostic value in differentiating small malignant from benign lymph nodes.

  18. Prognostic and accuracy data of multidetector CT coronary angiography in an established clinical service

    Energy Technology Data Exchange (ETDEWEB)

    Van Lingen, R. [Department of Cardiology, Derriford Hospital, Plymouth, Devon (United Kingdom)], E-mail: Robin.vanLingen@rcht.cornwall.nhs.uk; Kakani, N.; Veitch, A.; Manghat, N.E.; Roobottom, C.A. [Department of Clinical Radiology, Derriford Hospital, Plymouth, Devon (United Kingdom); Morgan-Hughes, G.J. [Department of Cardiology, Derriford Hospital, Plymouth, Devon (United Kingdom)

    2009-06-15

    Aim: To assess the accuracy of clinical coronary computed tomography angiography (CTA) data compared to invasive coronary angiography, and to determine the prognostic value of a negative coronary CTA examination in symptomatic, intermediate-risk patients. Methods: Thirty-seven months of coronary CTA data were audited. Seventy-eight patients were identified who had undergone coronary CTA followed by invasive coronary angiography (ICA) to determine the accuracy of CTA versus ICA. One hundred and seventy-eight patients were identified who had a 'negative' coronary CTA to enable evaluation of the prognostic value of a negative CTA examination. Results: Of the 78 patients in the accuracy analysis group there were 43 true-negative, two false-negative, 26 true-positive, and seven false-positive results producing a sensitivity of 92.9%, specificity of 86%, negative predictive value of 95.6%, and positive predictive value of 78.8%. The 178 patients who had a negative coronary CTA examination were followed up for a mean of 366 days and were all alive (0% mortality) with no episodes of myocardial infarction or unstable angina; two patients underwent elective revascularization procedures (1.1%). Conclusion: According to medium-term analysis, the accuracy of the clinical coronary CTA programme is in line with published trial data, producing excellent sensitivity and negative predictive values. The finding of a negative coronary CTA in symptomatic, intermediate-risk patients appears to confer a good prognosis, at mean follow-up of 1 year, with no deaths or episodes of myocardial infarction or unstable angina. This suggests that the prognostic value of a negative coronary CTA may be similar to that conferred by negative myocardial perfusion scintigraphy or stress echocardiography.

  19. Diagnostic accuracy of dual energy CT angiography in patients with diabetes mellitus; Diagnostische Genauigkeit der Dual-energy-CT-Angiographie bei Patienten mit Diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Schabel, C.; Bongers, M.N.; Syha, R. [Klinikum der Eberhard-Karls-Universitaet, Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Klinikum der Eberhard-Karls-Universitaet, Sektion fuer Experimentelle Radiologie der Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Ketelsen, D.; Homann, G.; Notohamiprodjo, M.; Nikolaou, K.; Bamberg, F. [Klinikum der Eberhard-Karls-Universitaet, Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Thomas, C. [Universitaetsklinikum Duesseldorf, Abteilung fuer Diagnostische und Interventionelle Radiologie, Duesseldorf (Germany)

    2015-04-01

    Peripheral arterial disease (PAD) represents a major and highly prevalent complication in patients with diabetes mellitus. The diagnostic, non-invasive work-up by computed tomography angiography (CTA) is limited in the presence of extensive calcification. The aim of the study was to determine the diagnostic accuracy of dual energy CTA (DE-CTA) for the detection and characterization of PAD in patients with diabetes mellitus. In this study 30 diabetic patients with suspected or known PAD were retrospectively included in the analysis. All subjects underwent DE-CTA (Somatom Definition Flash, Siemens Healthcare, Erlangen, Germany) prior to invasive angiography, which served as the reference standard. Blinded analysis included assessment of the presence and degree of peripheral stenosis on curved multiplanar reformatting (MPR) and maximum intensity projections (MIP). Conventional measures of diagnostic accuracy were derived. Among the 30 subjects included in the analysis (83 % male, mean age 70.0 ± 10.5 years, 83 % diabetes type 2), the prevalence of critical stenosis in 331 evaluated vessel segments was high (30 %). Dual energy CT identified critical stenoses with a high sensitivity and good specificity using curved MPR (100 % and 93.1 %, respectively) and MIP images (99 % and 91.8 %, respectively). In stratified analysis, the diagnostic accuracy was higher for stenosis pertaining to the pelvic and thigh vessels as compared with the lower extremities (curved MPR accuracy 97.1 % vs. 99.2 vs. 90.9 %; respectively, p < 0.001). The use of DE-CTA allows reliable detection and characterization of peripheral arterial stenosis in patients with diabetes mellitus with higher accuracy in vessels in the pelvic and thigh regions compared with the vessels in the lower legs. (orig.) [German] Die periphere arterielle Verschlusskrankheit (PAVK) ist eine wesentliche Komplikation des Diabetes mellitus und stellt aufgrund ausgepraegter Gefaessverkalkungen eine diagnostische

  20. Diagnostic accuracies of MR enterography and CT enterography in symptomatic Crohn's disease

    DEFF Research Database (Denmark)

    Jensen, Michael Dam; Kjeldsen, Jens; Rafaelsen, Søren Rafael;

    2011-01-01

    diagnostic accuracies for detection of small bowel CD and stenosis. In symptomatic patients with CD and high disease prevalence, positive predictive values are favorable but negative predictive values are low. Consequently, MRE and CTE can be relied upon, if a positive result is obtained whereas a negative......Abstract Objective. In patients, with symptomatic Crohn's disease (CD), valid information about the presence or absence of small bowel disease activity and stenosis is clinically important. Such information supports decisions about medical or surgical therapy and can be obtained with MR...

  1. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    DEFF Research Database (Denmark)

    Lynggaard Riis, Hans; Moltke, Lars N; Zimmermann, S. J.

    2016-01-01

    prior to treatment. Linac manufacturers offer tools for MV radiation isocentre localization. As a user, there is no access to the documentation for the underlying method and calculation algorithm used in the commercial software. The idea of this work was to evaluate the accuracy of the software tool......Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning...... for MV radiation isocentre calculation as delivered by Elekta using independent software. The image acquisition was based on the scheme designed by the manufacturer. Eight MV images were acquired in each series of a ball-bearing (BB) phantom attached to the treatment couch. The images were recorded...

  2. Diagnostic accuracy of 128-slice dual-source CT coronary angiography: a randomized comparison of different acquisition protocols

    Energy Technology Data Exchange (ETDEWEB)

    Neefjes, Lisan A.; Kate, Gert-Jan R. ten [Erasmus Medical Center, Department of Cardiology, Room Hs 207, P.O. Box 2040, Rotterdam (Netherlands); Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Interuniversity Cardiology Institute of the Netherlands, Utrecht (Netherlands); Rossi, Alexia; Nieman, Koen; Papadopoulou, Stella L.; Dharampal, Anoeshka S.; Dedic, Admir; Feyter, Pim J. de; Mollet, Nico R. [Erasmus Medical Center, Department of Cardiology, Room Hs 207, P.O. Box 2040, Rotterdam (Netherlands); Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Genders, Tessa S.S.; Hunink, M.G.M. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus Medical Center, Department of Epidemiology, Rotterdam (Netherlands); Schultz, Carl J. [Erasmus Medical Center, Department of Cardiology, Room Hs 207, P.O. Box 2040, Rotterdam (Netherlands); Weustink, Annick C.; Dijkshoorn, Marcel L.; Straten, Marcel van; Cademartiri, Filippo; Krestin, Gabriel P. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands)

    2013-03-15

    To compare the diagnostic performance and radiation exposure of 128-slice dual-source CT coronary angiography (CTCA) protocols to detect coronary stenosis with more than 50 % lumen obstruction. We prospectively included 459 symptomatic patients referred for CTCA. Patients were randomized between high-pitch spiral vs. narrow-window sequential CTCA protocols (heart rate below 65 bpm, group A), or between wide-window sequential vs. retrospective spiral protocols (heart rate above 65 bpm, group B). Diagnostic performance of CTCA was compared with quantitative coronary angiography in 267 patients. In group A (231 patients, 146 men, mean heart rate 58 {+-} 7 bpm), high-pitch spiral CTCA yielded a lower per-segment sensitivity compared to sequential CTCA (89 % vs. 97 %, P = 0.01). Specificity, PPV and NPV were comparable (95 %, 62 %, 99 % vs. 96 %, 73 %, 100 %, P > 0.05) but radiation dose was lower (1.16 {+-} 0.60 vs. 3.82 {+-} 1.65 mSv, P < 0.001). In group B (228 patients, 132 men, mean heart rate 75 {+-} 11 bpm), per-segment sensitivity, specificity, PPV and NPV were comparable (94 %, 95 %, 67 %, 99 % vs. 92 %, 95 %, 66 %, 99 %, P > 0.05). Radiation dose of sequential CTCA was lower compared to retrospective CTCA (6.12 {+-} 2.58 vs. 8.13 {+-} 4.52 mSv, P < 0.001). Diagnostic performance was comparable in both groups. Sequential CTCA should be used in patients with regular heart rates using 128-slice dual-source CT, providing optimal diagnostic accuracy with as low as reasonably achievable (ALARA) radiation dose. circle 128-slice dual-source CT coronary angiography offers several different acquisition protocols. (orig.)

  3. Diagnostic accuracy of dual-source CT coronary angiography with prospective ECG-triggering on different heart rate patients

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ming-li; Lu, Bin; Han, Lei; Liu, Gang; Yu, Fang-Fang; Hou, Zhi-hui; Gao, Yang; Wang, Hong-yu; Jiang, Shiliang [Peking Union Medical College, Department of Radiology, Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences, Beijing (China); Wu, Run-ze; Johnson, Laura [CT Research Collaboration, Siemens Healthcare, Shang Hai (China); Yang, Yue-jin; Qiao, Shu-bin [Chinese Academy of Medical Sciences, Peking Union Medical College, Department of Cardiology, Division of Coronary Heart Disease, Cardiovascular Institute and Fu Wai Hospital, Beijing (China)

    2011-08-15

    To evaluate the diagnostic accuracy of dual-source CT (DSCT) prospective ECG-triggering coronary angiography in patients with different heart rate (HR). 103 patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography (ICA). The patients were grouped by HR during CT scans: low HR ({<=}60 bpm, n = 34); medium HR (60 < HR {<=} 70 bpm, n = 36) and high HR (>70 bpm, n = 33). The sensitivity and specificity of DSCT in detecting {>=}50% stenosis were compared among subgroups where ICA was the gold standard. Image quality was scored using a 4-point scale. A total of 1,580 (95.9%) coronary artery segments were evaluable. Sensitivity and specificity were 82.8% and 98.4%, 88.3% and 98.7%, and 80.3% and 98.6% for different subgroups (all p > 0.05). The overall area under the curve of the receiver-operating characteristic analysis was 0.94. The image quality scores were 3.1 {+-} 0.3, 3.1 {+-} 0.3 and 3.0 {+-} 0.4 for subgroups (p > 0.05). The overall average effective radiation dose was 3.60 {+-} 1.60 mSv. DSCT coronary angiography with prospective ECG-triggering could be just as accurate in patients with medium to high HR compared to those with low HR. (orig.)

  4. Accuracy of hydro-multidetector row CT in the local T staging of oesophageal cancer compared to postoperative histopathological results

    Energy Technology Data Exchange (ETDEWEB)

    Ba-Ssalamah, Ahmed; Matzek, Wolfgang; Baroud, Susanne; Bastati, Nina; Weber, Michael; Herold, Christian J. [Medical University of Vienna, Department of Radiology, Vienna (Austria); Zacherl, Johannes; Schoppmann, Sebastian F. [Medical University of Vienna, Department of Radiology, Vienna (Austria); Medical University of Vienna, Department of Surgery, Vienna (Austria); Hejna, Michael [Medical University of Vienna, Department of Radiology, Vienna (Austria); Medical University of Vienna, Department of Oncology, Vienna (Austria); Wrba, Fritz [Medical University of Vienna, Department of Radiology, Vienna (Austria); Medical University of Vienna, Department of Pathology, Vienna (Austria); Gore, Richard M. [University of Chicago Pritzker School of Medicine, Department of Radiology, Chicago, IL (United States)

    2011-11-15

    To evaluate the accuracy of multidetector computed tomography with water filling (Hydro-MDCT) in the T-staging of patients with oesophageal cancer. There were 131 consecutive patients who were preoperatively and prospectively examined in the prone position on arterial phase contrast-enhanced MDCT, after ingestion of 1,000-1,500 ml tap water and effervescent granules. Two readers staged the local tumour growth (T-staging) independently. They assessed tumour location, size, presence of stenosis, and morphology of the outer border of the oesophageal wall and perioesophageal fat planes on CT. CT findings were compared with histopathological results from resected specimens. Data were analyzed using the SPSS statistical package. Both readers obtained a high sensitivity of 95% and a high positive predictive value of 96%. Accurate local staging was achieved in 76.3% and 68.7% for readers 1 and 2, respectively. Inter-reader agreement was excellent (weighted {kappa} value of 0.93 and un-weighted {kappa} of 0.89). Using the hydro-technique and applying specific assessment criteria, MDCT appears to be an accurate, non-invasive diagnostic tool for local tumour staging of oesophageal cancer. (orig.)

  5. Accuracy of 64-slice CT angiography for the detection of functionally relevant coronary stenoses as assessed with myocardial perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Gaemperli, Oliver; Schepis, Tiziano; Koepfli, Pascal; Valenta, Ines; Soyka, Jan [University Hospital Zurich NUK C 40, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Leschka, Sebastian; Desbiolles, Lotus; Husmann, Lars; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich NUK C 40, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); University of Zurich, Zurich Center for Integrative Human Physiology (CIHP), Zurich (Switzerland)

    2007-08-15

    CT angiography (CTA) offers a valuable alternative for the diagnosis of CAD but its value in the detection of functionally relevant coronary stenoses remains uncertain. We prospectively compared the accuracy of 64-slice CTA with that of myocardial perfusion imaging (MPI) using {sup 99m}Tc-tetrofosmin-SPECT as the gold standard for the detection of functionally relevant coronary artery disease (CAD). MPI and 64-slice CT were performed in 100 consecutive patients. CTA lesions were analysed quantitatively and area stenoses {>=}50% and {>=}75% were compared with the MPI findings. In 23 patients, MPI perfusion defects were found (12 reversible, 13 fixed). A total of 399 coronary arteries and 1,386 segments was analysed. Eighty-four segments (6.1%) in 23 coronary arteries (5.8%) of nine patients (9.0%) were excluded owing to insufficient image quality. In the remaining 1,302 segments, quantitative CTA revealed stenoses {>=}50% in 57 of 376 coronary arteries (15.2%) and stenoses {>=}75% in 32 (8.5%) coronary arteries. Using a cut-off at {>=}75% area stenosis, CTA yielded the following sensitivity, specificity, negative (NPV) and positive predictive value (PPV), and accuracy for the detection of any (fixed and reversible) MPI defect: by patient, 75%, 90%, 93%, 68% and 87%, respectively; by artery, 76%, 95%, 99%, 50% and 94%, respectively. Sixty-four-slice CTA is a reliable tool to rule out functionally relevant CAD in a non-selected population with an intermediate pretest likelihood of disease. However, an abnormal CTA is a poor predictor of ischaemia. (orig.)

  6. Accuracy of multidetector-row CT in diagnosing lymph node metastasis in patients with gastric cancer

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Takuro; Kurokawa, Yukinori; Takiguchi, Shuji; Miyazaki, Yasuhiro; Takahashi, Tsuyoshi; Yamasaki, Makoto; Miyata, Hiroshi; Nakajima, Kiyokazu; Mori, Masaki; Doki, Yuichiro [Osaka University, Graduate School of Medicine, Department of Gastroenterological Surgery, Suita, Osaka (Japan)

    2014-08-06

    The purpose of this study was to determine the optimal cut-off value of lymph node size for diagnosing metastasis in gastric cancer with multidetector-row computed tomography (MDCT) after categorizing perigastric lymph nodes into three regions. The study included 90 gastric cancer patients who underwent gastrectomy. The long-axis diameter (LAD) and short-axis diameter (SAD) of all visualized lymph nodes were measured with transverse MDCT images. The locations of lymph nodes were categorized into three regions: lesser curvature, greater curvature, and suprapancreatic. The diagnostic value of lymph node metastasis was assessed with receiver operating characteristic (ROC) analysis. The area under the curve was larger for SAD than LAD in all groups. The optimal cut-off values of SAD were determined as follows: overall, 9 mm; differentiated type, 9 mm; undifferentiated type, 8 mm; lesser curvature region, 7 mm; greater curvature region, 6 mm; and suprapancreatic region, 9 mm. The diagnostic accuracies for lymph node metastasis using individual cut-off values were 71.1 % based on histological type and 76.6 % based on region of lymph node location. The diagnostic accuracy of lymph node metastasis in gastric cancer was improved by using individual cut-off values for each lymph node region. (orig.)

  7. Diagnostic yield and accuracy of CT angiography, MR angiography, and digital subtraction angiography for detection of macrovascular causes of intracerebral haemorrhage: prospective, multicentre cohort study

    OpenAIRE

    van Asch, Charlotte J. J.; Birgitta K Velthuis; Rinkel, Gabriël J E; Algra, Ale; de Kort, Gerard A. P.; Witkamp, Theo D.; de Ridder, Johanna C M; van Nieuwenhuizen, Koen M.; De Leeuw, Frank Erik; Schonewille, Wouter J.; de Kort, Paul L. M.; Dippel, Diederik W; Raaymakers, Theodora W M; Hofmeijer, Jeannette; Wermer, Marieke J. H.

    2015-01-01

    Study question What are the diagnostic yield and accuracy of early computed tomography (CT) angiography followed by magnetic resonance imaging/angiography (MRI/MRA) and digital subtraction angiography (DSA) in patients with non-traumatic intracerebral haemorrhage? Methods This prospective diagnostic study enrolled 298 adults (18-70 years) treated in 22 hospitals in the Netherlands over six years. CT angiography was performed within seven days of haemorrhage. If the result was negative, MRI/MR...

  8. Cone beam CT evaluation of patient set-up accuracy as a QA tool

    DEFF Research Database (Denmark)

    Nielsen, Morten; Bertelsen, Anders; Westberg, Jonas;

    2009-01-01

    and methods. Eighty four cancer patients have been cone beam CT scanned at treatment sessions 1, 2, 3, 10 and 20. Translational and rotational errors are analyzed. Results and conclusions. For the first three treatment sessions the mean translational error in the AP direction is 1 mm; this indicates a small...... error in the calibration of coronal isocentric laser. The observed SD of the systematic error in each direction is 1 mm if a correction is made after the third fraction with an action limit of 4 mm. The SD of the random errors of the patient group is approximately 1 mm in each direction. The rotational...... errors have a vanishing mean and a systematic error of 0.5 1.2 degrees and a random error of 0.40.7 degrees. The uncertainties from the first three treatment sessions (disregarding rotations) lead to a margin of 4 mm from ITV to PTV for Head-and-Neck patients (all directions) and Thorax patients (AP...

  9. Activity-monitor accuracy in measuring step number and cadence in community-dwelling older adults.

    Science.gov (United States)

    Grant, P Margaret; Dall, Philippa M; Mitchell, Sarah L; Granat, Malcolm H

    2008-04-01

    The primary purpose of this study was to investigate the accuracy of the activPAL physical activity monitor in measuring step number and cadence in older adults. Two pedometers (New-Lifestyles Digi-Walker SW-200 and New-Lifestyles NL2000) used in clinical practice to count steps were simultaneously evaluated. Observation was the criterion measure. Twenty-one participants (65-87 yr old) recruited from community-based exercise classes walked on a treadmill at 5 speeds (0.67, 0.90, 1.12, 1.33, and 1.56 m/s) and outdoors at 3 self-selected speeds (slow, normal, and fast). The absolute percentage error of the activPAL was <1% for all treadmill and outdoor conditions for measuring steps and cadence. With the exception of the slowest treadmill speed, the NL-2000 error was <2%. The SW-200 was the least accurate device, particularly at slower walking speeds. The activPAL monitor accurately recorded step number and cadence. Combined with its ability to identify primary postures, the activPAL might be a useful and versatile device for measuring activity in older adults.

  10. Diagnostic Accuracy of Detecting Hashimoto's Thyroiditis in Thyroid Cancer Patients Who Underwent Thyroid Surgery: Comparison of Ultrasonography, Positron Emission Tomography/CT, Contrast Enhanced CT, and Anti-Thyroid Antibody

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Gyun; Lee, Tae Hyun; Park, Dong Hee; Nam, Sang Been [Dept. of Radiology, Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    2012-11-15

    To compare the diagnostic accuracy of ultrasonography (US), F18-fluorodeoxyglucose positron emission tomography/CT (PET/CT), contrast enhanced CT (CECT), serum anti-thyroid antibody for detecting Hashimoto's thyroiditis in thyroid cancer patients who underwent neck surgery. A total of 150 patients with suspicious for thyroid cancer, who had previously undergone US guided needle aspiration of thyroid, were evaluated with the use of US, PET/CT, CECT and serum anti-thyroid antibody. The four studies were performed within two months before neck surgery. Hashimoto's thyroiditis was confirmed by histopathological results. The diagnostic accuracy of US, PET/CT, CECT and serum anti-thyroid antibody were calculated statistically. Hashimoto's thyroiditis was diagnosed in 51 out of the 150 patients, following neck surgery. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of US were 76.5%, 92.9%, 84.8%, 88.5%, and 87.3%, respectively. The corresponding values of PET/CT were 37.3%, 96.0%, 82.6%, 74.8%, and 76.0%, and CECT were 62.7%, 89.9%, 76.2%, 82.4%, and 80.7%, and serum anti-thyroid antibody level were 90.2%, 93.9%, 88.5%, 94.9%, and 92.7%, respectively. McNemar test revealed significant difference among PET/CT and others, but no significant differences among US, CECT and serum anti-thyroid antibody. Overall, serum anti-thyroid antibody showed most accurate diagnostic performance. In detecting Hashimoto's thyroiditis, serum anti-thyroid antibody showed higher diagnostic accuracy than others. US also showed relatively high diagnostic accuracy.

  11. Thoracolumbar instrumentation with CT-guided navigation (O-arm) in 270 consecutive patients: accuracy rates and lessons learned.

    Science.gov (United States)

    Rivkin, Mark A; Yocom, Steven S

    2014-03-01

    Thoracolumbar instrumentation has experienced a dramatic increase in utilization over the last 2 decades. However, pedicle screw fixation remains a challenging undertaking, with suboptimal placement contributing to postoperative pain, neurological deficit, vascular complications, and return to the operating suite. Image-guided spinal surgery has substantially improved the accuracy rates for these procedures. However, it is not without technical challenges and a learning curve for novice operators. The authors present their experience with the O-arm intraoperative imaging system and share the lessons they learned over nearly 5 years. The authors performed a retrospective chart review of 270 consecutive patients who underwent thoracolumbar pedicle screw fixation utilizing the O-arm imaging system in conjunction with StealthStation navigation between April 2009 and September 2013 at a single tertiary care center; 266 of the patients underwent CT scanning on postoperative Day 1 to evaluate hardware placement. The CT scans were interpreted prospectively by 3 neuroradiologists as part of standard work flow and retrospectively by 2 neurosurgeons and a senior resident. Pedicle screws were evaluated for breaches according to the 3-tier classification proposed by Mirza et al. Of 270 patients, 266 (98.5%) were included in the final analysis based on the presence of a postoperative CT scan. Overall, 1651 pedicle screws were placed in 266 patients and yielded a 5.3% breach rate; 213 thoracic and 1438 lumbosacral pedicle screws were inserted with 6.6% and 5.1% breach rates, respectively. Of the 87 suboptimally placed screws, there were 13 Grade 1, 16 Grade 2, and 12 Grade 3 misses as well as 46 anterolateral or "tip-out" perforations at L-5. Four patients (1.5%) required a return to the operating room for pedicle screw revision, 2 of whom experienced transient radicular symptoms and 2 remained asymptomatic. Interestingly, the pedicle breach rate was higher than anticipated at 13

  12. Dual-energy CT perfusion and angiography in chronic thromboembolic pulmonary hypertension: diagnostic accuracy and concordance with radionuclide scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Dournes, Gael; Verdier, Damien; Montaudon, Michel; Laurent, Francois; Lederlin, Mathieu [Hopital Haut-Leveque, CHU Bordeaux, Department of Medical Imaging, Pessac (France); University Bordeaux Segalen, Bordeaux Cedex (France); Bullier, Eric; Riviere, Annalisa [Hopital Haut-Leveque, CHU Bordeaux, Department of Nuclear Medicine, Pessac (France); Dromer, Claire [Hopital Haut-Leveque, CHU Bordeaux, Department of Respiratory Diseases, Pessac (France); Picard, Francois [Hopital Haut-Leveque, CHU Bordeaux, Department of Cardiology, Pessac (France); Billes, Marc-Alain [Hopital Haut-Leveque, CHU Bordeaux, Department of Cardiac Surgery, Pessac (France); Corneloup, Olivier [Hopital Haut-Leveque, CHU Bordeaux, Department of Medical Imaging, Pessac (France)

    2014-01-15

    To evaluate the diagnostic accuracy of dual-energy computed tomography (DECT) perfusion and angiography versus ventilation/perfusion (V/Q) scintigraphy in chronic thromboembolic pulmonary hypertension (CTEPH), and to assess the per-segment concordance rate of DECT and scintigraphy. Forty consecutive patients with proven pulmonary hypertension underwent V/Q scintigraphy and DECT perfusion and angiography. Each imaging technique was assessed for the location of segmental defects. Diagnosis of CTEPH was established when at least one segmental perfusion defect was detected by scintigraphy. Diagnostic accuracy of DECT perfusion and angiography was assessed and compared with scintigraphy. In CTEPH patients, the per-segment concordance between scintigraphy and DECT perfusion/angiography was calculated. Fourteen patients were diagnosed with CTEPH and 26 with other aetiologies. DECT perfusion and angiography correctly identified all CTEPH patients with sensitivity/specificity values of 1/0.92 and 1/0.93, respectively. At a segmental level, DECT perfusion showed moderate agreement (κ = 0.44) with scintigraphy. Agreement between CT angiography and scintigraphy ranged from fair (κ = 0.31) to slight (κ = 0.09) depending on whether completely or partially occlusive patterns were considered, respectively. Both DECT perfusion and angiography show satisfactory performance for the diagnosis of CTEPH. DECT perfusion is more accurate than angiography at identifying the segmental location of abnormalities. (orig.)

  13. Accuracy of CT angiography in the assessment of a fetal origin of the posterior cerebral artery

    Energy Technology Data Exchange (ETDEWEB)

    Lugt, A. van der; Buter, T.C.; Govaere, F.; Siepman, D.A.M.; Tanghe, H.L.J.; Dippel, D.W.J. [Department of Radiology, Erasmus MC, Rotterdam (Netherlands)

    2004-09-01

    An uncommon cause of cerebral ischemia in the territory of the posterior cerebral artery (PCA) is the combination of a fetal origin of the PCA and atherosclerotic disease in the internal carotid artery. This study compared the accuracy of CTA with DSA in the assessment of a fetal origin of the PCA. Patients in whom an intracranial DSA and CTA had been performed were reviewed. A fetal origin was defined as a normal-sized patent posterior communicating artery (PCoA) with hypoplasia or aplasia of the ipsilateral P1 segment. One hundred PCAs in 51 patients were analyzed. A fetal origin was present in ten vessels (10%, eight patients). CTA revealed all of them. CTA considered an additional three vessels as having a fetal origin, while DSA revealed a PCoA with the same diameter as the P1 segment of the PCA. Sensitivity and specificity of CTA in the assessment of a fetal origin could be estimated at 100 and 97%, respectively. Positive and negative predictive values were 77 and 100%, respectively. CTA can be considered a valid diagnostic tool for the assessment of a fetal origin of the PCA in patients with a cerebral ischemic event in the territory of the PCA. (orig.)

  14. Diagnostic accuracy of whole-brain CT perfusion in the detection of acute infratentorial infarctions

    Energy Technology Data Exchange (ETDEWEB)

    Bollwein, Christine; Sommer, Wieland H.; Thierfelder, Kolja M.; Reiser, Maximilian F. [Ludwig-Maximilians-University Hospital of Munich, Institute for Clinical Radiology, Munich (Germany); Plate, Annika; Straube, Andreas; Baumgarten, Louisa von [Ludwig-Maximilians-University Hospital of Munich, Department of Neurology, Munich (Germany); Janssen, Hendrik [South Nuremberg Hospital, Department of Neuroradiology, Nuremberg (Germany)

    2016-11-15

    Although the diagnostic performance of whole-brain computed tomographic perfusion (WB-CTP) in the detection of supratentorial infarctions is well established, its value in the detection of infratentorial strokes remains less well defined. We examined its diagnostic accuracy in the detection of infratentorial infarctions and compared it to nonenhanced computed tomography (NECT), aiming to identify factors influencing its detection rate. Out of a cohort of 1380 patients who underwent WB-CTP due to suspected stroke, we retrospectively included all patients with MRI-confirmed infratentorial strokes and compared it to control patients without infratentorial strokes. Two blinded readers evaluated NECT and four different CTP maps independently for the presence and location of infratentorial ischemic perfusion deficits. The study was designed as a retrospective case-control study and included 280 patients (cases/controls = 1/3). WB-CTP revealed a greater diagnostic sensitivity than NECT (41.4 vs. 17.1 %, P = 0.003). The specificity, however, was comparable (93.3 vs. 95.0 %). Mean transit time (MTT) and time to drain (TTD) were the most sensitive (41.4 and 40.0 %) and cerebral blood volume (CBV) the most specific (99.5 %) perfusion maps. Infarctions detected using WB-CTP were significantly larger than those not detected (15.0 vs. 2.2 ml; P = 0.0007); infarct location, however, did not influence the detection rate. The detection of infratentorial infarctions can be improved by assessing WB-CTP as part of the multimodal stroke workup. However, it remains a diagnostic challenge, especially small volume infarctions in the brainstem are likely to be missed. (orig.)

  15. Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, Mohd Fahmi Mohd, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, Sabar [School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hashim, Rokiah [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-04-29

    Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ{sup 2} value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ{sup 2} value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.

  16. Diagnostic accuracy of {sup 18}F-FDG PET/CT for detection of suspected recurrence in patients with oesophageal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Punit; Jain, Sachin; Karunanithi, Sellam; Malhotra, Arun; Bal, Chandrasekhar; Kumar, Rakesh [All India Institute of Medical Sciences, Department of Nuclear Medicine, New Delhi (India); Pal, Sujoy [All India Institute of Medical Sciences, Department of Surgical Gastroenterology, New Delhi (India); Julka, Pramod Kumar [All India Institute of Medical Sciences, Department of Radiation Oncology, New Delhi (India); Thulkar, Sanjay [All India Institute of Medical Sciences, Department of Radiodiagnosis, New Delhi (India)

    2014-06-15

    To evaluate the role of {sup 18}F-FDG PET/CT in the detection of recurrence in patients with oesophageal carcinoma, suspected clinically or following conventional investigations. This was a retrospective study. Data from 180 patients (age 56.3 ± 10.4 years; 126 men, 54 women) with histopathologically proven oesophageal carcinoma (squamous cell 115, adenocarcinoma 59, neuroendocrine carcinoma 4, small cell 1, poorly differentiated 1) who had undergone 227 {sup 18}F-FDG PET/CT studies for suspected recurrence were analysed. Recurrence was suspected clinically or following conventional investigations. PET/CT images were revaluated by two nuclear medicine physicians in consensus. Findings were grouped into local, nodal and distant recurrence. Results were compared to those from contrast-enhanced (CE) CT when available (109 patients). Clinical/imaging follow-up (minimum 6 months) with histopathology (when available) was taken as the reference standard. Of the 227 {sup 18}F-FDG PET/CT studies,166 were positive and 61 were negative for recurrent disease. PET/CT showed local recurrence in 134, nodal recurrence in 115 and distant recurrence in 47, with more than one site of recurrence in 34. The PET/CT findings were true-positive in 153 studies, true-negative in 54, false-positive in 13 and false-negative in 7. The sensitivity of {sup 18}F-FDG PET/CT was 96 %, the specificity was 81 %, the positive and negative predictive values were 92 % and 89 %, respectively, and the accuracy was 91 %. PET/CT showed similar accuracy in patients with squamous cell carcinoma and in those with adenocarcinoma (P = 0.181).{sup 18}F-FDG PET/CT was more specific than CECT (67 % vs. 21 %; P < 0.0001). PET/CT was superior to CECT for the detection of nodal recurrence (P < 0.0001), but not local recurrence (P = 0.093) or distant metastases (P = 0.441). {sup 18}F-FDG PET/CT shows high accuracy in the detection of suspected recurrence in patients with oesophageal carcinoma. It is more specific than

  17. Diagnostic accuracy of {sup 18}F-FDG-PET and PET/CT in patients with Ewing sarcoma family tumours: a systematic review and a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Treglia, Giorgio [Institute of Nuclear Medicine, Catholic University of the Sacred Heart, Department of Bioimaging and Radiological Sciences, Rome (Italy); Institute of Nuclear Medicine, Positron Emission Tomography Centre, Catholic University of the Sacred Heart, Department of Bioimaging and Radiological Sciences, Rome (Italy); Salsano, Marco; Stefanelli, Antonella; Mattoli, Maria Vittoria; Giordano, Alessandro [Institute of Nuclear Medicine, Catholic University of the Sacred Heart, Department of Bioimaging and Radiological Sciences, Rome (Italy); Bonomo, Lorenzo [Institute of Radiology, Catholic University of the Sacred Heart, Department of Bioimaging and Radiological Sciences, Rome (Italy)

    2012-03-15

    To systematically review and meta-analyse literature data on the diagnostic performance of fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) and positron emission tomography/computed tomography (PET/CT) in patients with Ewing sarcoma family tumours (ESFT). PubMed/MEDLINE, Embase and Scopus databases were searched for articles that evaluated FDG-PET and PET/CT in patients with ESFT from inception to 31 May 2011. Studies that fulfilled the three following criteria were included in the systematic review: FDG-PET or PET/CT performed in patients with ESFT; articles about the diagnostic accuracy of FDG-PET and PET/CT; sample size of at least 10 patients with ESFT were included. Studies in which there were sufficient data to reassess sensitivity and specificity of FDG-PET or PET/CT in ESFT were included in the meta-analysis, excluding duplicate publications. Finally, pooled sensitivity, pooled specificity and area under the receiver operating characteristic (ROC) curve of FDG-PET or PET/CT in ESFT were calculated. We found 13 studies comprising a total of 342 patients with ESFT. The main findings of the studies included are presented. The meta-analysis of five selected studies provided these results about FDG-PET and PET/CT in ESFT: pooled sensitivity: 96% (95% confidence interval [CI] 91-99%); pooled specificity: 92% (95% CI 87-96%); area under the ROC curve: 0.97. With regard to the staging and restaging of patients with ESFT, the sensitivity, specificity and accuracy of FDG-PET and PET/CT are high; the combination of FDG-PET or PET/CT with conventional imaging is a valuable tool for the staging and restaging of ESFT and has a relevant impact on the treatment strategy plan. (orig.)

  18. Intrinsic dependencies of CT radiomic features on voxel size and number of gray levels.

    Science.gov (United States)

    Shafiq-Ul-Hassan, Muhammad; Zhang, Geoffrey G; Latifi, Kujtim; Ullah, Ghanim; Hunt, Dylan C; Balagurunathan, Yoganand; Abdalah, Mahmoud Abrahem; Schabath, Matthew B; Goldgof, Dmitry G; Mackin, Dennis; Court, Laurence Edward; Gillies, Robert James; Moros, Eduardo Gerardo

    2017-03-01

    voxel-size normalized features were used for interscanner comparisons. A subsequent analysis investigated feature dependency on gray-level discretization by extracting 51 texture features from ROIs from each of the 10 different phantom cartridges using 16, 32, 64, 128, and 256 gray levels. Out of the 213 features extracted, 150 were reproducible across voxel sizes, 42 improved significantly (%COV variations before and after resampling (Group 1). Ten features improved significantly after definition modification effectively removed their voxel-size dependency. Interscanner comparison indicated that feature variability among scanners nearly vanished for 8 of these 10 features. Furthermore, 17 out of 51 texture features were found to be dependent on the number of gray levels. These features were redefined to include the number of gray levels which greatly reduced this dependency. Voxel-size resampling is an appropriate pre-processing step for image datasets acquired with variable voxel sizes to obtain more reproducible CT features. We found that some of the radiomics features were voxel size and gray-level discretization-dependent. The introduction of normalizing factors in their definitions greatly reduced or removed these dependencies. © 2017 American Association of Physicists in Medicine.

  19. Accuracy of estimation of graft size for living-related liver transplantation: first results of a semi-automated interactive software for CT-volumetry.

    Directory of Open Access Journals (Sweden)

    Theresa Mokry

    Full Text Available OBJECTIVES: To evaluate accuracy of estimated graft size for living-related liver transplantation using a semi-automated interactive software for CT-volumetry. MATERIALS AND METHODS: Sixteen donors for living-related liver transplantation (11 male; mean age: 38.2±9.6 years underwent contrast-enhanced CT prior to graft removal. CT-volumetry was performed using a semi-automated interactive software (P, and compared with a manual commercial software (TR. For P, liver volumes were provided either with or without vessels. For TR, liver volumes were provided always with vessels. Intraoperative weight served as reference standard. Major study goals included analyses of volumes using absolute numbers, linear regression analyses and inter-observer agreements. Minor study goals included the description of the software workflow: degree of manual correction, speed for completion, and overall intuitiveness using five-point Likert scales: 1--markedly lower/faster/higher for P compared with TR, 2--slightly lower/faster/higher for P compared with TR, 3--identical for P and TR, 4--slightly lower/faster/higher for TR compared with P, and 5--markedly lower/faster/higher for TR compared with P. RESULTS: Liver segments II/III, II-IV and V-VIII served in 6, 3, and 7 donors as transplanted liver segments. Volumes were 642.9±368.8 ml for TR with vessels, 623.8±349.1 ml for P with vessels, and 605.2±345.8 ml for P without vessels (P<0.01. Regression equations between intraoperative weights and volumes were y = 0.94x+30.1 (R2 = 0.92; P<0.001 for TR with vessels, y = 1.00x+12.0 (R2 = 0.92; P<0.001 for P with vessels, and y = 1.01x+28.0 (R2 = 0.92; P<0.001 for P without vessels. Inter-observer agreement showed a bias of 1.8 ml for TR with vessels, 5.4 ml for P with vessels, and 4.6 ml for P without vessels. For the degree of manual correction, speed for completion and overall intuitiveness, scale values were 2.6±0.8, 2.4±0.5 and 2. CONCLUSIONS

  20. Effect of CT scanning parameters on CT number%CT扫描参数对人体组织CT值影响的研究

    Institute of Scientific and Technical Information of China (English)

    彭文献; 彭天舟; 叶小琴; 付益谋; 潘慧平; 高源统; 金光波

    2010-01-01

    目的 探索不同CT扫描参数对人体同一种组织CT值的影响.方法 通过在同一台CT机上,分别改变其中1个扫描参数,如X线管电压、毫安秒和重建函数等,而保持其他扫描参数不变,多次扫描标准体模,测量和分析体模中不同物质的CT值.结果 X线管电压的改变对物质的CT值影响具有显著意义.聚乙烯、聚碳酸酯、有机玻璃的CT值与管电压成正相关;聚四氟乙烯的CT值与管电压成负相关.毫安秒和重建函数对CT值的影响差异无统计学意义.结论 同一个人体组织在不同的X线管电压条件下CT值是变化的.因此,在临床影像诊断和放疗中应该考虑图像扫描参数的设置对诊断和治疗结果的影响.%Objective To study the effects on tissue CT number caused by scan protocols.Methods The phantom was repeatedly scanned in different protocols by changing only one of parameters,such as X-ray tube voltage,mAs and recon kernel,while other parameters were ketp unchanged.The CT number of different materials in phantom were measured and analyzed.Results The CT numbers of tissues changed remarkably with the tube voltage and had different relativity for different tissues.The CT numbers had positive correlation with kV for such maierials as polyethyle,lexan,perspex,but for teflon the correlation was negative.The mAs and recon kernel had no effects on CT number.Conclusions The CT number of tissue changes with scanning X-ray tube voltage,so the setting of scan parameters should be taken into account in image diagnosis and radiotherapy.

  1. Tracker-on-C for cone-beam CT-guided surgery: evaluation of geometric accuracy and clinical applications

    Science.gov (United States)

    Reaungamornrat, S.; Otake, Y.; Uneri, A.; Schafer, S.; Mirota, D. J.; Nithiananthan, S.; Stayman, J. W.; Khanna, A. J.; Reh, D. D.; Gallia, G. L.; Taylor, R. H.; Siewerdsen, J. H.

    2012-02-01

    Conventional surgical tracking configurations carry a variety of limitations in line-of-sight, geometric accuracy, and mismatch with the surgeon's perspective (for video augmentation). With increasing utilization of mobile C-arms, particularly those allowing cone-beam CT (CBCT), there is opportunity to better integrate surgical trackers at bedside to address such limitations. This paper describes a tracker configuration in which the tracker is mounted directly on the Carm. To maintain registration within a dynamic coordinate system, a reference marker visible across the full C-arm rotation is implemented, and the "Tracker-on-C" configuration is shown to provide improved target registration error (TRE) over a conventional in-room setup - (0.9+/-0.4) mm vs (1.9+/-0.7) mm, respectively. The system also can generate digitally reconstructed radiographs (DRRs) from the perspective of a tracked tool ("x-ray flashlight"), the tracker, or the C-arm ("virtual fluoroscopy"), with geometric accuracy in virtual fluoroscopy of (0.4+/-0.2) mm. Using a video-based tracker, planning data and DRRs can be superimposed on the video scene from a natural perspective over the surgical field, with geometric accuracy (0.8+/-0.3) pixels for planning data overlay and (0.6+/-0.4) pixels for DRR overlay across all C-arm angles. The field-of-view of fluoroscopy or CBCT can also be overlaid on real-time video ("Virtual Field Light") to assist C-arm positioning. The fixed transformation between the x-ray image and tracker facilitated quick, accurate intraoperative registration. The workflow and precision associated with a variety of realistic surgical tasks were significantly improved using the Tracker-on-C - for example, nearly a factor of 2 reduction in time required for C-arm positioning, reduction or elimination of dose in "hunting" for a specific fluoroscopic view, and confident placement of the x-ray FOV on the surgical target. The proposed configuration streamlines the integration of C

  2. Effects of CT Number-Derived Matrix Density on Preferential Flow and Transport in Macroporous Agricultural Soil

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Møldrup, Per; Lamande, Mathieu André Maurice;

    2015-01-01

    permeability, saturated hydraulic conductivity, and solute transport. This was due to the limited CT scan resolution and large structural variability below this resolution. However, CTmatrix, a new parameter derived from the CT number of the matrix excluding stones and large mostly air-filled macropores...... risks to public health. This study focused on establishing links between the structural pore space and preferential transport using a combination of standard physical measurement methods for air and water permeabilities, breakthrough experiments, and X-ray computed tomography (CT) on large soil columns....... Substantial structural heterogeneity that resulted in significant variations in flow and tracer transport was observed, despite the textural similarity of the investigated samples. Quantification of macropore characteristics with X-ray CT was useful but not sufficient to explain the variability in air...

  3. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    NARCIS (Netherlands)

    Liang, X.; Lambrichts, I.; Sun, Y.; Denis, K.; Hassan, B.; Li, L.; Pauwels, R.; Jacobs, R.

    2010-01-01

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G,

  4. Accuracy of combined PET/CT in image-guided interventions of liver lesions: An ex-vivo study

    Institute of Scientific and Technical Information of China (English)

    Patrick Veit; Christiane Kuehle; Thomas Beyer; Hilmar Kuehl; Andreas Bockisch; Gerald Antoch

    2006-01-01

    AIM: Positioning of interventional devices in liver lesions is a challenging task if only CT is available. We investigated the potential benefit of combined PET/CT images for localization of interventional devices in interventional liver studies.METHODS: Thirty lesions each of hyperdense, isodense and hypodense attenuation compared to normal liver parenchyma were injected into 15 ex-vivo pig livers. All lesions were composed of the same amounts of gelatine containing 0.5 MBq of 18F-FDG. Following lesion insertion, an interventional needle was placed in each lesion under CT-guidance solely. After that, a PET/CT study was performed. The localization of the needle within the lesion was assessed for CT alone and PET/CT and the root mean square (RMS) was calculated. Results were compared with macroscopic measurements after lesion dissection serving as the standard of reference. RESULTS: In hypo- and isodense lesions PET/CT proved more accurate in defining the position of the interventional device when compared with CT alone. The mean RMS for CT and PET/CT differed significantly in isodense and hypodense lesions. No significant difference was found for hyperdense lesions.CONCLUSION: Combined FDG-PET/CT imaging provides more accurate information than CT alone concerning the needle position in FDG-PET positive liver lesions.Therefore combined PET/CT might be potentially beneficial not only for localization of an interventional device,but may also be beneficial for guidance in interventional liver procedures.

  5. Accuracy and complications of CT-guided core needle biopsy of peripheral nerve sheath tumours

    Energy Technology Data Exchange (ETDEWEB)

    Pianta, Marcus; Chock, Eric; Schlicht, Stephen [St Vincent' s Hospital, Fitzroy, VIC (Australia); McCombe, David [St Vincent' s Hospital and Victorian Hand Surgery Associates, Victoria (Australia)

    2015-09-15

    This single-centre study retrospectively reviews the complications in patients that have occurred following peripheral nerve sheath tumour biopsy, and assesses whether there is an association with biopsy technique or underlying lesion characteristics. 41 consecutive core needle biopsies of proven peripheral nerve sheath tumours over a 2-year period in a tertiary teaching hospital were reviewed. Patient demographics and symptoms, tumour characteristics and radiological appearances were recorded. Biopsy and surgical histology were correlated, and post-biopsy and surgical complications analyzed. 41 biopsies were performed in 38 patients. 68 % schwannomas, 24 % neurofibromas and 7 % malignant peripheral nerve sheath tumours. Biopsy histology correlated with surgery in all cases. 71 % of lesions were surgically excised. 60 % of patients reported pain related to their lesion. Following the biopsy, 12 % reported increased pain, which resolved in all cases. Pain exacerbation was noted in tumours smaller in size, more superficial and in closer proximity of the biopsy needle tip to the traversing nerve. Number of biopsy needle passes was not associated with an increased incidence of procedure-related pain. Core biopsy of a suspected peripheral nerve sheath tumour may be performed safely before excisional surgery to confirm lesion histology and assist prognosis. There is excellent correlation between core biopsy and excised surgical specimen histology. The most common complication of pain exacerbation is seen in a minority and is temporary, and more likely with smaller, more superficial lesions and a closer needle-tip to traversing nerve distance during biopsy. (orig.)

  6. Diagnostic performance of whole brain volume perfusion CT in intra-axial brain tumors: Preoperative classification accuracy and histopathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Xyda, Argyro, E-mail: argyro.xyda@med.uni-goettingen.de [Department of Neuroradiology, Georg-August University, University Hospital of Goettingen, Robert-Koch Strasse 40, 37075 Goettingen (Germany); Department of Radialogy, University Hospital of Heraklion, Voutes, 71110 Heraklion, Crete (Greece); Haberland, Ulrike, E-mail: ulrike.haberland@siemens.com [Siemens AG Healthcare Sector, Computed Tomography, Siemensstr. 1, 91301 Forchheim (Germany); Klotz, Ernst, E-mail: ernst.klotz@siemens.com [Siemens AG Healthcare Sector, Computed Tomography, Siemensstr. 1, 91301 Forchheim (Germany); Jung, Klaus, E-mail: kjung1@uni-goettingen.de [Department of Medical Statistics, Georg-August University, Humboldtallee 32, 37073 Goettingen (Germany); Bock, Hans Christoph, E-mail: cbock@gmx.de [Department of Neurosurgery, Johannes Gutenberg University Hospital of Mainz, Langenbeckstraße 1, 55101 Mainz (Germany); Schramm, Ramona, E-mail: ramona.schramm@med.uni-goettingen.de [Department of Neuroradiology, Georg-August University, University Hospital of Goettingen, Robert-Koch Strasse 40, 37075 Goettingen (Germany); Knauth, Michael, E-mail: michael.knauth@med.uni-goettingen.de [Department of Neuroradiology, Georg-August University, University Hospital of Goettingen, Robert-Koch Strasse 40, 37075 Goettingen (Germany); Schramm, Peter, E-mail: p.schramm@med.uni-goettingen.de [Department of Neuroradiology, Georg-August University, University Hospital of Goettingen, Robert-Koch Strasse 40, 37075 Goettingen (Germany)

    2012-12-15

    Background: To evaluate the preoperative diagnostic power and classification accuracy of perfusion parameters derived from whole brain volume perfusion CT (VPCT) in patients with cerebral tumors. Methods: Sixty-three patients (31 male, 32 female; mean age 55.6 ± 13.9 years), with MRI findings suspected of cerebral lesions, underwent VPCT. Two readers independently evaluated VPCT data. Volumes of interest (VOIs) were marked circumscript around the tumor according to maximum intensity projection volumes, and then mapped automatically onto the cerebral blood volume (CBV), flow (CBF) and permeability Ktrans perfusion datasets. A second VOI was placed in the contra lateral cortex, as control. Correlations among perfusion values, tumor grade, cerebral hemisphere and VOIs were evaluated. Moreover, the diagnostic power of VPCT parameters, by means of positive and negative predictive value, was analyzed. Results: Our cohort included 32 high-grade gliomas WHO III/IV, 18 low-grade I/II, 6 primary cerebral lymphomas, 4 metastases and 3 tumor-like lesions. Ktrans demonstrated the highest sensitivity, specificity and positive predictive value, with a cut-off point of 2.21 mL/100 mL/min, for both the comparisons between high-grade versus low-grade and low-grade versus primary cerebral lymphomas. However, for the differentiation between high-grade and primary cerebral lymphomas, CBF and CBV proved to have 100% specificity and 100% positive predictive value, identifying preoperatively all the histopathologically proven high-grade gliomas. Conclusion: Volumetric perfusion data enable the hemodynamic assessment of the entire tumor extent and provide a method of preoperative differentiation among intra-axial cerebral tumors with promising diagnostic accuracy.

  7. Diagnostic accuracy of segmental enhancement inversion for the diagnosis of renal oncocytoma using biphasic computed tomography (CT) and multiphase contrast-enhanced magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Schieda, Nicola; McInnes, Matthew D.F. [The University of Ottawa, The Ottawa Hospital, Department of Medical Imaging, Ottawa, Ontario (Canada); Al-Subhi, Maali; Flood, Trevor A.; El-Khodary, Mohammed [The University of Ottawa, The Ottawa Hospital, Department of Anatomical Pathology, Ottawa, ON (Canada)

    2014-11-15

    Segmental enhancement inversion (SEI) is a controversial imaging finding reportedly specific for the diagnosis of renal oncocytoma. The purpose of this study was to re-evaluate SEI using biphasic CT and multiphase MRI. With research ethics board approval, a retrospective analysis of patients with resection or biopsy of oncocytoma or chromophobe renal cell carcinoma (Ch-RCC) between 2008-2012 was performed. Twenty-four patients with oncocytoma and 13 patients with Ch-RCC underwent CT, while 13 patients with oncocytoma and 10 patients with Ch-RCC underwent MRI. Two blinded radiologists reviewed the CT and MRI studies independently in separate sessions to assess for SEI. A third radiologist established consensus. Interobserver variability was calculated and diagnostic accuracy was compared using ROC and the Fisher exact test. There was no difference in detection of SEI between oncocytoma and Ch-RCC at CT [both readers (p = 0.65, 0.5) and consensus review (p = 0.29)] or MRI [both readers (p = 0.64, 0.74) and consensus review (p = 0.53)]. The interobserver variability at CT (K = 0.28-0.33) and MRI (K = 0.25-0.44) was fair. The sensitivity and specificity for diagnosis of oncocytoma were 21 % and 92 % at CT and 15 % and 90 % at MRI. SEI is not useful for the diagnosis of renal oncocytoma with CT or MRI. (orig.)

  8. Accuracy of integrated FDG-PET/contrast-enhanced CT in detecting pelvic and paraaortic lymph node metastasis in patients with uterine cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kitajima, Kazuhiro [Dokkyo University School of Medicine, Department of Radiology, Mibu, Shimotuka-gun, Tochigi (Japan); Dokkyo Medical University Hospital, PET Center, Mibu (Japan); Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Murakami, Koji; Yamasaki, Erena [Dokkyo Medical University Hospital, PET Center, Mibu (Japan); Kaji, Yasushi [Dokkyo University School of Medicine, Department of Radiology, Mibu, Shimotuka-gun, Tochigi (Japan); Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan)

    2009-06-15

    The purpose is to evaluate the accuracy of integrated {sup 18}F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) with intravenous contrast medium in detecting pelvic and paraaortic lymph node metastasis in patients with uterine cancer, with surgical and histopathological findings used as the reference standard. Forty-five patients with endometrial or uterine cervical cancer underwent radical hysterectomy, including pelvic lymphadenectomy with or without paraaortic lymphadenectomy, after PET/CT. PET/CT findings were interpreted by two experienced radiologists in consensus. The criterion for malignancy on PET/CT images was increased tracer uptake by the lymph node, independent of node size. The overall node-based sensitivity, specificity, PPV, NPV and accuracy of PET/CT for detecting nodal metastases were 51.1% (23/45), 99.8% (1,927/1,931), 85.2% (23/27), 98.9% (1,927/1,949) and 98.7% (1,950/1,976), respectively. The sensitivity for detecting metastatic lesions 4 mm or less in short-axis diameter was 12.5% (2/16), that for between 5 and 9 mm was 66.7% (16/24), and that for 10 mm or larger was 100.0% (5/5). The overall patient-based sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 50% (6/12), 90.9% (30/33), 66.7% (6/9), 83.3% (30/36) and 80.0% (36/45), respectively. Integrated FDG-PET/contrast-enhanced CT is superior to conventional imaging, but only moderately sensitive in predicting lymph node metastasis preoperatively in patients with uterine cancer. (orig.)

  9. Diagnostic accuracy of {sup 18}F-FDG PET/CT for assessing response to radiofrequency ablation treatment in lung metastases: a multicentre prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Bonichon, Francoise; Godbert, Yann; Cazeau, Anne-Laure [Institut Bergonie, Department of Nuclear Medicine, Bordeaux (France); Palussiere, Jean; Descat, Edouard [Institut Bergonie, Department of Interventional Radiology, Bordeaux (France); Pulido, Marina [Institut Bergonie, Unit of Clinical Epidemiology and Clinical Research, Bordeaux (France); Cancer Trial Data Center, INCa, Bordeaux (Centre de Traitement des Donnees de Bordeaux, Institut National du Cancer), Bordeaux (France); Devillers, Anne [Eugene Marquis Anticancer Centre, Department of Nuclear Medicine, Rennes (France); Meunier, Catherine [Centre Hospitalier Universitaire, Department of Radiology, Rennes (France); Leboulleux, Sophie [Institut Gustave Roussy, University Paris Sud, Department of Nuclear Medicine and Endocrine Oncology, Villejuif (France); Baere, Thierry de [Institut Gustave Roussy, Department of Interventional Radiology, Villejuif (France); Galy-Lacour, Claire [Centre Hospitalier de la Cote Basque, Department of Nuclear Medicine, Bayonne (France); Lagoarde-Segot, Laurent [Centre Hospitalier de la Cote Basque, Department of Medical Imaging, Bayonne (France)

    2013-12-15

    To assess diagnostic accuracy of {sup 18}F-FDG PET/CT at 3 months for the detection of local recurrence after radiofrequency ablation (RFA) of lung metastases. The PET/CT scan at 3 months was compared with a baseline PET/CT scan from a maximum of 2 months before RFA, with the reference standard as recurrence diagnosed by CT during a 12-month follow-up. Local recurrence was diagnosed on the PET/CT scan if lesional uptake was greater than the mediastinal background. Maximum standardized uptake values (SUVmax) were recorded. ROC curve analysis for SUVmax was performed. Overall survival (OS) and time to local relapse were computed from the date of RFA using the Kaplan-Meier method (www.clinicaltrials.gov: NCT 00382252). Between 2005 and 2009, 89 patients (mean age 65 years) underwent RFA for 115 lung metastases (mean size 16.2 {+-} 6.9 mm). The median SUVmax before RFA was 5.8 {+-} 4. PET/CT at 3 months and the reference standard were available in 77 patients and 100 lesions. Accuracy was 66.00 % (95 % CI 55.85-75.18 %), sensitivity 90.91 % (95 % CI 58.72-99.77 %), specificity 62.92 % (95 % CI 52.03-72.93 %), PPV 23.26 % (95 % CI 11.76-38.63 %), and NPV 98.25 % (95 % CI 90.61-99.96 %). One-year OS was 94.2 % (95 % CI 86.6-97.5 %) and the probability of being free of local recurrence 1 year after RFA was 84.6 % (95 % CI 75.0-90.8 %). The specificity of PET/CT at 3 months is low because of persistent inflammation, especially when the lesion is close to the pleura. This technique is useful for its negative predictive value, but positive findings need to be confirmed by histology before new treatment is planned. (orig.)

  10. Improved dose calculation accuracy for low energy brachytherapy by optimizing dual energy CT imaging protocols for noise reduction using sinogram affirmed iterative reconstruction.

    Science.gov (United States)

    Landry, Guillaume; Gaudreault, Mathieu; van Elmpt, Wouter; Wildberger, Joachim E; Verhaegen, Frank

    2016-03-01

    The goal of this study was to evaluate the noise reduction achievable from dual energy computed tomography (CT) imaging (DECT) using filtered backprojection (FBP) and iterative image reconstruction algorithms combined with increased imaging exposure. We evaluated the data in the context of imaging for brachytherapy dose calculation, where accurate quantification of electron density ρe and effective atomic number Zeff is beneficial. A dual source CT scanner was used to scan a phantom containing tissue mimicking inserts. DECT scans were acquired at 80 kVp/140Sn kVp (where Sn stands for tin filtration) and 100 kVp/140Sn kVp, using the same values of the CT dose index CTDIvol for both settings as a measure for the radiation imaging exposure. Four CTDIvol levels were investigated. Images were reconstructed using FBP and sinogram affirmed iterative reconstruction (SAFIRE) with strength 1,3 and 5. From DECT scans two material quantities were derived, Zeff and ρe. DECT images were used to assign material types and the amount of improperly assigned voxels was quantified for each protocol. The dosimetric impact of improperly assigned voxels was evaluated with Geant4 Monte Carlo (MC) dose calculations for an (125)I source in numerical phantoms. Standard deviations for Zeff and ρe were reduced up to a factor ∼2 when using SAFIRE with strength 5 compared to FBP. Standard deviations on Zeff and ρe as low as 0.15 and 0.006 were achieved for the muscle insert representing typical soft tissue using a CTDIvol of 40 mGy and 3mm slice thickness. Dose calculation accuracy was generally improved when using SAFIRE. Mean (maximum absolute) dose errors of up to 1.3% (21%) with FBP were reduced to less than 1% (6%) with SAFIRE at a CTDIvol of 10 mGy. Using a CTDIvol of 40mGy and SAFIRE yielded mean dose calculation errors of the order of 0.6% which was the MC dose calculation precision in this study and no error was larger than ±2.5% as opposed to errors of up to -4% with FPB. This

  11. Understanding less than nothing: Children’s neural response to negative numbers shifts across age and accuracy

    Directory of Open Access Journals (Sweden)

    Margaret M Gullick

    2013-09-01

    Full Text Available We examined the brain activity underlying the development of our understanding of negative numbers, which are amounts lacking direct physical counterparts. Children performed a paired comparison task with positive and negative numbers during an fMRI session. As previously shown in adults, both pre-instruction fifth graders and post-instruction seventh graders demonstrated typical behavioral and neural distance effects to negative numbers, where response times and parietal and frontal activity increased as comparison distance decreased. We then determined the factors impacting the distance effect in each age group. Behaviorally, the fifth grader distance effect for negatives was significantly predicted only by positive comparison accuracy, indicating that children who were generally better at working with numbers were better at comparing negatives. In seventh graders, negative comparison accuracy significantly predicted their distance effect, indicating that children who were better at working with negative numbers demonstrated a more typical distance effect. Across children, as age increased, the negative number distance effect increased in the bilateral IPS and decreased frontally, indicating a frontoparietal shift consistent with previous numerical development literature. In contrast, as task accuracy increased, the parietal distance effect increased in the left IPS and decreased in the right, possibly indicating a change from an approximate understanding of negatives’ values to a more exact, precise representation (particularly supported by the left IPS with increasing expertise. These shifts separately indicate the effects of increasing maturity generally in numeric processing and specifically in negative number understanding.

  12. C-arm cone-beam CT virtual navigation-guided percutaneous mediastinal mass biopsy: Diagnostic accuracy and complications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyungjin [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Aerospace Medical Group, Air Force Education and Training Command, Jinju (Korea, Republic of); Park, Chang Min; Goo, Jin Mo [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Seoul National University, Cancer Research Institute, Seoul (Korea, Republic of); Lee, Sang Min [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of)

    2015-12-15

    To assess the usefulness of C-arm cone-beam computed tomography (CBCT) virtual navigation-guided percutaneous mediastinal mass biopsy in terms of diagnostic accuracy and complication rates. Seventy-eight CBCT virtual navigation-guided percutaneous mediastinal mass biopsies were performed in 75 patients (M:F, 38:37; mean age, 48.55 ± 18.76 years). The procedural details, diagnostic sensitivity, specificity, accuracy and complication rate were investigated. Mean lesion size was 6.80 ± 3.08 cm, skin-to-target distance was 3.67 ± 1.80 cm, core needle biopsy rate was 96.2 % (75/78), needle indwelling time was 9.29 ± 4.34 min, total procedure time was 13.26 ± 5.29 min, number of biopsy specimens obtained was 3.13 ± 1.02, number of CBCTs performed was 3.03 ± 0.68, rate of lesion border discrimination from abutting mediastinal structures on CBCT was 26.9 % (21/78), technical success rate was 100 % (78/78), estimated effective dose was 5.33 ± 4.99 mSv, and the dose area product was 12,723.68 ± 10,665.74 mGy.cm{sup 2}. Among the 78 biopsies, 69 were malignant, 7 were benign and 2 were indeterminate. Diagnostic sensitivity, specificity and accuracy for the diagnosis of malignancies were 97.1 % (67/69), 100 % (7/7) and 97.4 % (74/76), respectively, with a complication rate of 3.85 % (3/78), all of which were small pneumothoraces. CBCT virtual navigation-guided biopsy is a highly accurate and safe procedure for the evaluation of mediastinal lesions. (orig.)

  13. Evaluation of the effects of sagging shifts on isocenter accuracy and image quality of cone-beam CT from kV on-board imagers.

    Science.gov (United States)

    Ali, Imad; Ahmad, Salahuddin

    2009-07-17

    To investigate the effects of sagging shifts of three on-board kV imaging systems (OBI) on the isocenter positioning accuracy and image quality of cone-beam CT (CBCT). A cubical phantom having a metal marker in the center that can be aligned with the radiation isocenter was used to measure sagging shifts and their variation with gantry angle on three Varian linacs with kV on-board imaging systems. A marker-tracking algorithm was applied to detect the shadow of the metal marker and localize its center in the two-dimensional cone-beam radiographic projections. This tracking algorithm is based on finding the position of maximum cross-correlation between a region-of-interest from a template image (including the metal marker) and the projections containing the shadow of the metal marker. Sagging shifts were corrected by mapping the center of the metal marker to a reference position for all projections acquired over a full gantry rotation (0-360 degrees). The sag-corrected radiographic projections were then used to reconstruct CBCT using Feldkamp back-projection. A standard quality assurance phantom was used to evaluate the image quality of CBCT before and after sagging correction. Sagging affects both the positioning accuracy of the OBI isocenter and the CBCT image quality. For example, on one linac, the position of the marker on the cone-beam radiographic projections depends on the angular view and has maximal shifts of about 2 mm along the imager x-direction (patient's cross-plane). Sagging produces systematic shifts of the OBI isocenter as large as 1 mm posterior and 1 mm left in patient coordinates relative to the radiation isocenter. Further, it causes spatial distortion and blurring in CBCT image reconstructed from radiographic projections that are not corrected for OBI sagging. CBCT numbers vary by about 1% in full-fan scans and up to 3.5% in half-fan scans because of sagging. In order to achieve better localization accuracy in image-guided radiation therapy

  14. Accuracy of coronary plaque detection and assessment of interobserver agreement for plaque quantification using automatic coronary plaque analysis software on coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Laqmani, A.; Quitzke, M.; Creder, D.D.; Adam, G.; Lund, G. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology and Nuclearmedicine; Klink, T. [Wuerzburg Univ. (Germany). Inst. of Diagnostic and Interventional Radiology

    2016-10-15

    To evaluate the accuracy of automatic plaque detection and the interobserver agreement of automatic versus manually adjusted quantification of coronary plaques on coronary CT angiography (cCTA) using commercially available software. 10 cCTA datasets were evaluated using plaque software. First, the automatically detected plaques were verified. Second, two observers independently performed plaque quantification without revising the automatically constructed plaque contours (automatic approach). Then, each observer adjusted the plaque contours according to plaque delineation (adjusted approach). The interobserver agreement of both approaches was analyzed. 32 of 114 automatically identified findings were true-positive plaques, while 82 (72 %) were false-positive. 20 of 52 plaques (38 %) were missed by the software (false-negative). The automatic approach provided good interobserver agreement with relative differences of 0.9 ± 16.0 % for plaque area and -3.3 ± 33.8 % for plaque volume. Both observers independently adjusted all contours because they did not represent the plaque delineation. Interobserver agreement decreased for the adjusted approach with relative differences of 25.0 ± 24.8 % for plaque area and 20.0 ± 40.4 % for plaque volume. The automatic plaque analysis software is of limited value due to high numbers of false-positive and false-negative plaque findings. The automatic approach was reproducible but it necessitated adjustment of all constructed plaque contours resulting in deterioration of the interobserver agreement.

  15. Effects of number of events and relay point density on accuracy of three-dimensional AE-tomography

    NARCIS (Netherlands)

    Kobayashi, Y.; Shiotani, T.; Oda, K.

    2013-01-01

    This paper introduces results of numerical investigations on accuracy of elastic wave velocity distribution in Three-dimensional AE-Tomography. A series of numerical analyses is conducted by changing number of events and density of relay points for the investigation. AE-Tomography is an identificati

  16. Influence of measurement levels number on the accuracy of calculated estimate during the electrical energy measurements verification

    Science.gov (United States)

    Kochneva, E. S.; Sukalo, A.

    2017-07-01

    Verification of electric energy measurement is a very important issue. The research deals with the modified method of testing equations, which enables measurement-based electrical energy estimation of higher accuracy compared to the initial measurements. The influence of the testing equations number on the estimation error value is investigated. Test results are presented for 14-node IEEE scheme. The necessity of using the limited measurement level number is proved.

  17. Accuracy of single phase contrast enhanced multidetector CT colonography in the preoperative staging of colo-rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mainenti, Pier Paolo [IBB CNR, Via Pansini 5, 80131 Naples (Italy) and Department of Biomorphological and Functional Sciences, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy)]. E-mail: pierpamainenti@hotmail.com; Cirillo, Luigi Carlo [Department of Biomorphological and Functional Sciences, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy); Hospital ' dei Pellegrini' , ASLNA 1, Via Portamedina 41, 80100 Naples (Italy); Camera, Luigi [Department of Biomorphological and Functional Sciences, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy); Persico, Francesco [Department of General Surgery, Geriatry and Endoscopy, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy); Cantalupo, Teresa [Department of Biomorphological and Functional Sciences, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy); Pace, Leonardo [Department of Biomorphological and Functional Sciences, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy); Palma, Giovanni Domenico De [Department of General Surgery, Geriatry and Endoscopy, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy); Persico, Giovanni [Department of General Surgery, Geriatry and Endoscopy, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy); Salvatore, Marco [Department of Biomorphological and Functional Sciences, University of Naples ' Federico II' , Via Pansini 5, 80131 Naples (Italy)

    2006-12-15

    Aim: The optimal acquisition time for staging colo-rectal carcinoma with a contrast enhanced multidetector CT colonography (CE CTC) has not yet been established. A dual phase with both arterial and portal venous acquisition has been proposed. The purpose of our study is to assess the value of single portal venous phase CE CTC in the preoperative staging of colo-rectal carcinoma. Materials and methods: Fifty two (30 M, 22 F; aged 35-82 years) consecutive patients with a histologically proven diagnosis of colo-rectal adenocarcinoma or a highly suspected colo-rectal cancer on conventional colonoscopy underwent a four-slice CE CTC. The procedure was performed 70 s (portal phase) after the intravenous bolus (3 ml/s) administration of 120 ml iodinated non-ionic contrast agent (370 mg iodine/ml). Scans were performed using the following parameters: 2.5 mm beam collimation, pitch 1.25, 120 kV, 200 mAs, rotation time 0.75 s. Images were reconstructed with an effective thickness of 3.2 mm at intervals of 1.6 mm. Two radiologists independently evaluated the depth of tumour invasion into the colo-rectal wall (T), regional lymph node involvement (N), and extracolonic metastases (M). Disagreement was resolved by means of a consensus decision. The pathological results served as the standard of reference. Assessment was made of sensitivity, specificity and accuracy, as well as positive and negative predictive values were assessed. Results: CE CTC correctly staged the pT of 52/56 (93%) and the N of 40/56 (71%) lesions, as well as properly identifying 13/14 (93%) extracolonic findings. Conclusion: The single portal venous phase CE CTC scanning protocol enables satisfactory preoperative assessment of T, N and M staging in patients with colo-rectal cancer.

  18. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI.

    Science.gov (United States)

    Riis, Hans L; Moltke, Lars N; Zimmermann, Sune J; Ebert, Martin A; Rowshanfarzad, Pejman

    2016-06-07

    Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning prior to treatment. Linac manufacturers offer tools for MV radiation isocentre localization. As a user, there is no access to the documentation for the underlying method and calculation algorithm used in the commercial software. The idea of this work was to evaluate the accuracy of the software tool for MV radiation isocentre calculation as delivered by Elekta using independent software. The image acquisition was based on the scheme designed by the manufacturer. Eight MV images were acquired in each series of a ball-bearing (BB) phantom attached to the treatment couch. The images were recorded at cardinal angles of the gantry using the electronic portal imaging device (EPID). Eight Elekta linacs with three different types of multileaf collimators (MLCs) were included in the test. The influence of MLC orientation, x-ray energy, and phantom modifications were examined. The acquired images were analysed using the Elekta x-ray volume imaging (XVI) software and in-house developed (IHD) MATLAB code. Results from the two different software were compared. A discrepancy in the longitudinal direction of the isocentre localization was found averaging 0.23 mm up to a maximum of 0.75 mm. The MLC orientation or the phantom asymmetry in the longitudinal direction do not appear to cause the discrepancy. The main cause of the differences could not be clearly identified. However, it is our opinion that the commercial software delivered by the linac manufacturer should be improved to reach better stability and precise results in the MV radiation isocentre calculations.

  19. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion.

    Science.gov (United States)

    Jackman, Timothy M; DelMonaco, Alex M; Morgan, Elise F

    2016-01-25

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (μCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7-T9, n=28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12-279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms.

  20. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    Science.gov (United States)

    Riis, Hans L.; Moltke, Lars N.; Zimmermann, Sune J.; Ebert, Martin A.; Rowshanfarzad, Pejman

    2016-06-01

    Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning prior to treatment. Linac manufacturers offer tools for MV radiation isocentre localization. As a user, there is no access to the documentation for the underlying method and calculation algorithm used in the commercial software. The idea of this work was to evaluate the accuracy of the software tool for MV radiation isocentre calculation as delivered by Elekta using independent software. The image acquisition was based on the scheme designed by the manufacturer. Eight MV images were acquired in each series of a ball-bearing (BB) phantom attached to the treatment couch. The images were recorded at cardinal angles of the gantry using the electronic portal imaging device (EPID). Eight Elekta linacs with three different types of multileaf collimators (MLCs) were included in the test. The influence of MLC orientation, x-ray energy, and phantom modifications were examined. The acquired images were analysed using the Elekta x-ray volume imaging (XVI) software and in-house developed (IHD) MATLAB code. Results from the two different software were compared. A discrepancy in the longitudinal direction of the isocentre localization was found averaging 0.23 mm up to a maximum of 0.75 mm. The MLC orientation or the phantom asymmetry in the longitudinal direction do not appear to cause the discrepancy. The main cause of the differences could not be clearly identified. However, it is our opinion that the commercial software delivered by the linac manufacturer should be improved to reach better stability and precise results in the MV radiation isocentre calculations.

  1. SU-E-J-268: Change of CT Number During the Course of Chemoradiation Therapy for Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X; Dalah, E; Liu, F; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States); Zhang, J [Department of Radiation Oncology, Qianfoshan Hospital Affiliated to Shandon, Jinan, Shandong (China)

    2015-06-15

    Purpose: It has been observed radiation can induce changes in CT number (CTN) inside tumor during the course of radiation therapy (RT) for several tumor sites including lung and head and neck, suggesting that the CTN change may be potentially used to assess RT response. In this study, we investigate the CTN changes inside tumor during the course of chemoradiation therapy (CRT) for pancreatic cancer. Methods: Daily diagnostic-quality CT data acquired during IGRT for 17 pancreatic head cancer patients using an in-room CT (CTVision, Siemens) were analyzed. All patients were treated with a radiation dose of 50.4 in 1.8 Gy per fraction. On each daily CT set, The contour of the pancreatic head, included in the treatment target, was generated by populating the pancreatic head contour from the planning CT or MRI using an auto-segmentation tool based on deformable registration (ABAS, Elekta) with manual editing if necessary. The CTN at each voxel in the pancreatic head contour was extracted and the 3D distribution of the CTNs was processed using MATLAB. The mean value of CTN distribution was used to quantify the daily CTN change in the pancreatic head. Results: Reduction of CTN in pancreatic head was observed during the CRT delivery in 14 out the 17 (82%) patients studied. Although the average reduction is only 3.5 Houncefield Unit (HU), this change is significant (p<0.01). Among them, there are 7 patients who had a CTN drop larger than 5 HU, ranging from 6.0 to 11.8 HU. In contrast to this trend, CTN was increased in 3 patients. Conclusion: Measurable changes in the CT number in tumor target were observed during the course of chemoradiation therapy for the pancreas cancer patients, indicating this radiation-induced CTN change may be used to assess treatment response.

  2. Accuracy and reliability of thyroid volumetry using spiral CT and thyroid volume in a healthy, non-iodine-deficient Chinese adult population

    Energy Technology Data Exchange (ETDEWEB)

    Shu Jian, E-mail: shujiannc@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Zhao Jiannong, E-mail: zhaojiannong@tom.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Guo Dajing, E-mail: guodaj@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Luo Yindeng, E-mail: yindengluo_1019@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Zhong Weijia, E-mail: zhongweijia2003@eyou.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China); Xie Weibo, E-mail: radiologycq@163.com [Department of Radiology, Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010 (China)

    2011-02-15

    Objective: The purpose of this study was to assess the accuracy and reliability of thyroid volumetry using spiral CT and to investigate thyroid volumes for a healthy, non-iodine-deficient adult population in southwestern region of China. Materials and methods: Spiral CT was performed in phantoms and adult subjects with normal thyroid, and the volumes were measured by observers with 5 years or more of CT experience. The phantom volumes and the thyroid volumes of all subjects were noted. Results: For the thyroid phantoms, there was no significant difference between the true and CT calculated volumes (t = 0.862, P = 0.399), and the correlation was excellent (ICC = 0.9995, P = 0.000). In the subjects for reliability analysis, the intraobserver or interobserver differences for CT volumetric measurement of thyroid were not significant (P > 0.05). The intraobserver or interobserver correlations were very high (ICC > 0.99, P < 0.001). In the subjects for population analysis, the median of the thyroid volumes was 11.45 cm{sup 3}. The nonparametric Mann-Whitney U-test showed no significant difference for the thyroid volume between sexes (U = 4388.00, Z = -1.118, P = 0.264). The nonparametric Kruskall-Wallis test showed no significant difference in all age groups ({chi}{sup 2} = 13.466, P = 0.062). There was a slight negative correlation between the thyroid volume and age (r{sub s} = -0.166, P = 0.019). Conclusion: The accuracy and reliability of multi-slice spiral CT in measuring thyroid volume are very high. The thyroid volumes are not significantly difference between genders or among decades for the healthy, non-iodine-deficient adult population in southwestern region of China.

  3. Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain: prospective study and systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Alshamari, Muhammed; Geijer, Haakan [Oerebro University, Department of Radiology, Faculty of Medicine and Health, Oerebro (Sweden); Norrman, Eva [Oerebro University, Department of Medical Physics, Faculty of Medicine and Health, Oerebro (Sweden); Geijer, Mats [Lund University and Skaane University Hospital, Department of Medical Imaging and Physiology, Lund (Sweden); Jansson, Kjell [Oerebro University, Department of Surgery, Faculty of Medicine and Health, Oerebro (Sweden)

    2016-06-15

    Abdominal radiography is frequently used in acute abdominal non-traumatic pain despite the availability of more advanced diagnostic modalities. This study evaluates the diagnostic accuracy of low-dose CT compared with abdominal radiography, at similar radiation dose levels. Fifty-eight patients were imaged with both methods and were reviewed independently by three radiologists. The reference standard was obtained from the diagnosis in medical records. Sensitivity and specificity were calculated. A systematic review was performed after a literature search, finding a total of six relevant studies including the present. Overall sensitivity with 95 % CI for CT was 75 % (66-83 %) and 46 % (37-56 %) for radiography. Specificity was 87 % (77-94 %) for both methods. In the systematic review the overall sensitivity for CT varied between 75 and 96 % with specificity from 83 to 95 % while the overall sensitivity for abdominal radiography varied between 30 and 77 % with specificity 75 to 88 %. Based on the current study and available evidence, low-dose CT has higher diagnostic accuracy than abdominal radiography and it should, where logistically possible, replace abdominal radiography in the workup of adult patients with acute non-traumatic abdominal pain. (orig.)

  4. MRI combined with PET-CT of different tracers to improve the accuracy of glioma diagnosis: a systematic review and meta-analysis.

    Science.gov (United States)

    Yang, Yihan; He, Mike Z; Li, Tao; Yang, Xuejun

    2017-09-16

    Based on studies focusing on positron emission tomography (PET)-computed tomography (CT) combined with magnetic resonance imaging (MRI) in the diagnosis of glioma, we conducted a systematic review and meta-analysis evaluating the pros and cons and the accuracy of different examinations. PubMed and Cochrane Library were searched. The search was conducted until April 2017. Two reviewers independently conducted the literature search according to the criteria set initially. Based on the exclusion criteria, 15 articles are included in this study. Of all studies that used MRI examination, there are five involving 18F-fluorodeoxyglucose-PET, five involving 11C-methionine-PET, five involving 18F-fluoro-ethyl-tyrosine-PET, and three involving 18F-fluorothymidine-PET. Due to the limitations such as lack of data, small sample size, and unrepresentative studies, we use a non-quantitative methodology. MRI examination can provide the anatomy information of glioma more clearly. PET-CT examinations based on tumor metabolism using different tracers have more advantages in determining the degree of glioma malignancy and boundaries. However, information provided by PET-CT of different tracers is not the same. With respect to the novel hybrid MRI/PET examination equipment proposed in recent years, the combination of MRI and PET-CT can definitively improve the diagnostic accuracy of glioma.

  5. Diagnostic accuracy of whole-body PET/MRI and whole-body PET/CT for TNM staging in oncology

    Energy Technology Data Exchange (ETDEWEB)

    Heusch, Philipp [University Duesseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Duesseldorf (Germany); University Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Nensa, Felix; Beiderwellen, Karsten [University Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Schaarschmidt, Benedikt; Sivanesapillai, Rupika; Buchbender, Christian [University Duesseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Duesseldorf (Germany); Gomez, Benedikt; Ruhlmann, Verena [University Duisburg-Essen, Medical Faculty, Department of Nuclear Medicine, Essen (Germany); Koehler, Jens [University Duisburg-Essen, Medical Faculty, Department of Medical Oncology, Essen (Germany); Reis, Henning [University Duisburg-Essen, Medical Faculty, Institute of Pathology, Essen (Germany)

    2015-01-15

    In various tumours PET/CT with [{sup 18}F]FDG is widely accepted as the diagnostic standard of care. The purpose of this study was to compare a dedicated [{sup 18}F]FDG PET/MRI protocol with [{sup 18}F]FDG PET/CT for TNM staging in a cohort of oncological patients. A dedicated [{sup 18}F]FDG PET/MRI protocol was performed in 73 consecutive patients (mean age of 59 years, range 21 - 85 years) with different histologically confirmed solid primary malignant tumours after a routine clinical FDG PET/CT scan (60 min after injection of 295 ± 45 MBq [{sup 18}F]FDG). TNM staging according to the 7th edition of the AJCC Cancer Staging Manual was performed by two readers in separate sessions for PET/CT and PET/MRI images. Assessment of the primary tumour and nodal and distant metastases with FDG PET/CT and FDG PET/MRI was based on qualitative and quantitative analyses. Histopathology, and radiological and clinical follow-up served as the standards of reference. A McNemar test was performed to evaluate the differences in diagnostic performance between the imaging procedures. From FDG PET/CT and FDG PET/MRI T stage was correctly determined in 22 (82 %) and 20 (74 %) of 27 patients, N stage in 55 (82 %) and 56 (84 %) of 67 patients, and M stage in 32 (76 %) and 35 (83 %) of 42 patients, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for lymph node metastases were 65 %, 94 %, 79 %, 89 % and 87 % for PET/CT, and 63 %, 94 %, 80 %, 87 % and 85 % for PET/MRI. The respective values for the detection of distant metastases were 50 %, 82 %, 40 %, 88 % and 76 % for PET/CT, and 50 %, 91 %, 57 %, 89 % and 83 % for PET/MRI. Differences between the two imaging modalities were not statistically significant (P > 0.05). According to our results, FDG PET/CT and FDG PET/MRI are of equal diagnostic accuracy for TNM staging in patients with solid tumours. (orig.)

  6. Is diagnostic accuracy of 18F - FDG PET/CT different according to anatomical levels of cervical lymph node in restaging of papillary thyroid cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Ha, J. M.; Kwon, S. Y.; Seo, Y. S.; Chong, A. R.; Jeong, S. Y.; Jeong, Y. Y.; Min, J. J.; Song, H. C.; Bom, H. S. [Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2007-07-01

    To restage of thyroid papillary cancer, accurate detection of metastatic cervical lymph node (LN) is important. Therefore, we assessed the diagnostic accuracy of restaging 18F-FDG PET/CT according to anatomical levels of cervical LN. Thirty patients (F 19, M 11, mean age 49.2 y) with total thyroidectomy and regional LN dissection were included for restaging thyroid papillary carcinoma. We analyzed lymph node metastases according to anatomical level by AJCC 1996. Sixty nine LNs from these patients were analyzed by comparing PET/CT results with surgical pathology. We determined the cut-off value as maxSUV = 3.0 using ROC curve analysis. Overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of PET/CT was 81.1%, 59.4%, 69.8%, 73.1% and 71.1%, respectively. In each LN levels, level II showed 72.7%, 50%, 44.4%, 76.9%, 58%, level III 100%, 50%, 90%, 100%, 90.9%, level IV, 80%, 66.7%, 88.9%, 50%, 77%, level V 100%, 66.7%, 75%, 100%, 83.3%. Level I showed specificity of 100%, NPV of 80%, diagnostic accuracy of 80%. Level VI showed sensitivity of 100%, PPV of 100%, diagnostic accuracy of 100%. Out of total 14 false-positive, 10 was located in level II. There was no significant difference of maxSUV between benign and malignant lesion in level II LN group (p>0.05). But there were significant difference of maxSUV in other LN levels (p<0.01). PET/CT was useful for detecting metastatic or recurred cervical LNs in restaging of thyroid papillary cancer. However, because there can be many false-positive lesions in level II as compared to other levels, we need to apply different cut-off value of FDG uptake or consider other imaging modalities when we evaluate level II LNs.

  7. Hybrid Brain–Computer Interface Techniques for Improved Classification Accuracy and Increased Number of Commands: A Review

    Directory of Open Access Journals (Sweden)

    Keum-Shik Hong

    2017-07-01

    Full Text Available In this article, non-invasive hybrid brain–computer interface (hBCI technologies for improving classification accuracy and increasing the number of commands are reviewed. Hybridization combining more than two modalities is a new trend in brain imaging and prosthesis control. Electroencephalography (EEG, due to its easy use and fast temporal resolution, is most widely utilized in combination with other brain/non-brain signal acquisition modalities, for instance, functional near infrared spectroscopy (fNIRS, electromyography (EMG, electrooculography (EOG, and eye tracker. Three main purposes of hybridization are to increase the number of control commands, improve classification accuracy and reduce the signal detection time. Currently, such combinations of EEG + fNIRS and EEG + EOG are most commonly employed. Four principal components (i.e., hardware, paradigm, classifiers, and features relevant to accuracy improvement are discussed. In the case of brain signals, motor imagination/movement tasks are combined with cognitive tasks to increase active brain–computer interface (BCI accuracy. Active and reactive tasks sometimes are combined: motor imagination with steady-state evoked visual potentials (SSVEP and motor imagination with P300. In the case of reactive tasks, SSVEP is most widely combined with P300 to increase the number of commands. Passive BCIs, however, are rare. After discussing the hardware and strategies involved in the development of hBCI, the second part examines the approaches used to increase the number of control commands and to enhance classification accuracy. The future prospects and the extension of hBCI in real-time applications for daily life scenarios are provided.

  8. SU-E-J-272: Auto-Segmentation of Regions with Differentiating CT Numbers for Treatment Response Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C; Noid, G; Dalah, E; Paulson, E; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States); Gilat-Schmidt, T [Marquette University, Milwaukee, WI (United States)

    2015-06-15

    Purpose: It has been reported recently that the change of CT number (CTN) during and after radiation therapy (RT) may be used to assess RT response. The purpose of this work is to develop a tool to automatically segment the regions with differentiating CTN and/or with change of CTN in a series of CTs. Methods: A software tool was developed to identify regions with differentiating CTN using K-mean Cluster of CT numbers and to automatically delineate these regions using convex hull enclosing method. Pre- and Post-RT CT, PET, or MRI images acquired for sample lung and pancreatic cancer cases were used to test the software tool. K-mean cluster of CT numbers within the gross tumor volumes (GTVs) delineated based on PET SUV (standard uptake value of fludeoxyglucose) and/or MRI ADC (apparent diffusion coefficient) map was analyzed. The cluster centers with higher value were considered as active tumor volumes (ATV). The convex hull contours enclosing preset clusters were used to delineate these ATVs with color washed displays. The CTN defined ATVs were compared with the SUV- or ADC-defined ATVs. Results: CTN stability of the CT scanner used to acquire the CTs in this work is less than 1.5 Hounsfield Unit (HU) variation annually. K-mean cluster centers in the GTV have difference of ∼20 HU, much larger than variation due to CTN stability, for the lung cancer cases studied. The dice coefficient between the ATVs delineated based on convex hull enclosure of high CTN centers and the PET defined GTVs based on SUV cutoff value of 2.5 was 90(±5)%. Conclusion: A software tool was developed using K-mean cluster and convex hull contour to automatically segment high CTN regions which may not be identifiable using a simple threshold method. These CTN regions were reasonably overlapped with the PET or MRI defined GTVs.

  9. Accuracy of renal volume assessment in children by three-dimensional sonography; Nierenvolumetrie im Kindesalter: Genauigkeit der dreidimensionalen Sonographie im Vergleich zur konventionellen Sonographie und CT/MRT

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, G.A.; Riccabona, M.; Bohdal, G. [Klinik fuer Radiologie, Universitaetsklinikum Graz (Austria); Quehenberger, F. [Inst. fuer medizinische Informatik, Statistik und Dokumentation, Universitaetsklinikum Graz (Austria)

    2003-04-01

    Purpose: Prospective evaluation of the accuracy of three-dimensional ultrasound (3DUS) to assess the renal parenchymal volume. Materials and Methods: CT, MRI, 2DUS and 3DUS were used to measure the renal volume in 40 patients (range: neonate to 17 years; mean age: 8.95 years). The 3DUS was determined with a Voluson 730 (Kretztechnik, GE) or an external 3D-system (EchoTech, GE) using electromagnetic positioning sensors attached to conventional 2DUS-equipment. The 2DUS volume was calculated with the ellipsoid equation and the 3DUS volume computed with the system integrated software. For CT and MRI, planimetric analysis was used to determine the renal parenchymal volume, whereby the dilated collecting system of a hydronephrosis was subtracted to obtain the real renal parenchymal volume. The results of 2DUS and 3DUS were compared to the results of CT and MRI, and inter- and intraobserver variabilities were calculated. Results: In 74 of 77 kidneys, the 3DUS study was of diagnostic quality. The accuracy of the 3DUS volumes compared well to the CT and MRI volumes with a mean difference of -1.8 {+-} 4.6% versus a mean difference of -2.4 {+-} 15.4% for 2DUS. In normal kidneys, the accuracy was -2.6 {+-} 4.4% for 3DUS and -3.8 {+-} 14.7% for 2DUS. In hydronephrosis, the accuracy was +4.0 {+-} 5.9% and +9.6 {+-} 21.3%, respectively, indicating that 3DUS is more accurate than 2DUS, particularly in kidneys with a dilated collecting system. Inter- and intraobserver variabilities were {+-} 7.3% and {+-} 5.3%. Conclusion: For assessing the renal parenchymal volume in children, 3DUS is feasible and comparable to CT and MRI. (orig.) [German] Studienziel: Prospektive Evaluation der Genauigkeit des drei-dimensionalen Ultraschalls (3DUS) bei der Volumetrie der kindlichen Niere im Vergleich zur CT/MRT. Methode: Bei 40 Patienten (Alter: 0 - 17 Jahre) mit einer klinisch indizierten CT/MRT des Abdomens oder des Harntrakts wurde zusaetzlich ein 2D- und 3DUS inklusive Volumetrie des

  10. The effect of CT scanner parameters and 3D volume rendering techniques on the accuracy of linear, angular, and volumetric measurements of the mandible

    Science.gov (United States)

    Whyms, B.J.; Vorperian, H.K.; Gentry, L.R.; Schimek, E.M.; Bersu, E.T.; Chung, M.K.

    2013-01-01

    Objectives This study investigates the effect of scanning parameters on the accuracy of measurements from three-dimensional multi-detector computed tomography (3D-CT) mandible renderings. A broader range of acceptable parameters can increase the availability of CT studies for retrospective analysis. Study Design Three human mandibles and a phantom object were scanned using 18 combinations of slice thickness, field of view, and reconstruction algorithm and three different threshold-based segmentations. Measurements of 3D-CT models and specimens were compared. Results Linear and angular measurements were accurate, irrespective of scanner parameters or rendering technique. Volume measurements were accurate with a slice thickness of 1.25 mm, but not 2.5 mm. Surface area measurements were consistently inflated. Conclusions Linear, angular and volumetric measurements of mandible 3D-CT models can be confidently obtained from a range of parameters and rendering techniques. Slice thickness is the primary factor affecting volume measurements. These findings should also apply to 3D rendering using cone-beam-CT. PMID:23601224

  11. Diagnostic accuracy of cone-beam CT in the assessment of mandibular invasion of lower gingival carcinoma: Comparison with conventional panoramic radiography

    Energy Technology Data Exchange (ETDEWEB)

    Momin, Mohammad A. [Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: momin.orad@tmd.ac.jp; Okochi, Kiyoshi [Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: kiyoshi.orad@tmd.ac.jp; Watanabe, Hiroshi [Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: hiro.orad@tmd.ac.jp; Imaizumi, Akiko [Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: ima.orad@tmd.ac.jp; Omura, Ken [Oral Surgery, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: omura.osur@tmd.ac.jp; Amagasa, Teruo [Maxillofacial Surgery, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: t-amagasa.mfs@tmd.ac.jp; Okada, Norihiko [Diagnostic Oral Pathology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: nokd.opth@tmd.ac.jp; Ohbayashi, Naoto [Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: nao.orad@tmd.ac.jp; Kurabayashi, Tohru [Oral and Maxillofacial Radiology, Graduate School, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan)], E-mail: kura.orad@tmd.ac.jp

    2009-10-15

    Purpose: To evaluate the diagnostic accuracy of cone-beam CT in assessing mandibular invasion by lower gingival carcinoma and compare it with that of panoramic radiography. Patients and methods: Fifty patients with squamous cell carcinoma of the lower gingiva who were examined by both panoramic radiography and cone-beam CT before surgery were included in this study. Five radiologists used a 6-point rating scale to independently evaluate cone-beam CT and panoramic images for the presence or absence of alveolar bone and mandibular canal involvement by tumor. Using the histopathogical findings as the gold standard, we calculated and compared the area under the receiver operating characteristic curve (Az value) and the sensitivity and specificity of the two imaging modalities. Results: In evaluations of both alveolar bone and mandibular canal involvement, the mean Az value for cone-beam CT (0.918 and 0.977, respectively) was significantly higher than that for panoramic radiography (0.793 and 0.872, respectively). The mean sensitivity for cone-beam CT (89% and 99%, respectively) was significantly higher than that for panoramic radiography (73% and 56%, respectively). There was no significant difference in the mean specificity. While cone-beam CT could provide high-resolution three-dimensional images, the image quality around the alveolar crest was often hampered by severe dental artifacts and image noise, resulting in difficulties in detecting subtle alveolar invasion. Conclusion: Cone-beam CT was significantly superior to panoramic radiography in evaluating mandibular invasion by lower gingival carcinoma. Its diagnostic value in detecting subtle alveolar invasion, however, may be limited by severe dental artifacts and image noise.

  12. TU-EF-304-06: A Comparison of CT Number to Relative Linear Stopping Power Conversion Curves Used by Proton Therapy Centers

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, P; Lowenstein, J; Kry, S; Ibbott, G; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To compare the CT Number (CTN) to Relative Linear Stopping Power (RLSP) conversion curves used by 14 proton institutions in their dose calculations. Methods: The proton institution’s CTN to RLSP conversion curves were collected by the Imaging and Radiation Oncology Core (IROC) Houston QA Center during its on-site dosimetry review audits. The CTN values were converted to scaled CT Numbers. The scaling assigns a CTN of 0 to air and 1000 to water to allow intercomparison. The conversion curves were compared and the mean curve was calculated based on institutions’ predicted RLSP values for air (CTN 0), lung (CTN 250), fat (CTN 950), water (1000), liver (CTN 1050), and bone (CTN 2000) points. Results: One institution’s curve was found to have a unique curve shape between the scaled CTN of 1025 to 1225. This institution modified its curve based on the findings. Another institution had higher RLSP values than expected for both low and high CTNs. This institution recalibrated their two CT scanners and the new data placed their curve closer to the mean of all institutions. After corrections were made to several conversion curves, four institutions still fall outside 2 standard deviations at very low CTNs (100–200), and two institutions fall outside between CTN 850–900. The largest percent difference in RLSP values between institutions for the specific tissues reviewed was 22% for the lung point. Conclusion: The review and comparison of CTN to RLSP conversion curves allows IROC Houston to identify any outliers and make recommendations for improvement. Several institutions improved their clinical dose calculation accuracy as a Result of this review. There is still area for improvement, particularly in the lung area of the curve. The IROC Houston QA Center is supported by NCI grant CA180803.

  13. Diagnostic accuracy of dual-time-point 18F-FDG PET/CT for the detection of axillary lymph node metastases in breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Steffen; Forsting, Michael [Dept. of Diagnostic and Interventional Radiology and Neuroradiology, Univ. Hospital Essen, Univ. at Duisburg-Essen, Essen (Germany)], e-mail: steffen.hahn@uk-essen.de; Hecktor, Jennifer; Kimmig, Rainer [Dept. of Gynecology and Obstetrics, Univ. Hospital Essen, Univ. at Duisburg-Essen, Essen (Germany); Grabellus, Florian [Institute of Pathology and Neuropathology, Univ. Hospital Essen, Univ. at Duisburg-Essen, Essen (Germany); Hartung, Verena; Poeppel, Thorsten [Dept. of Nuclear Medicine, Univ. Hospital Essen, Univ. at Duisburg-Essen, Essen (Germany); Antoch, Gerald; Heusner, Till A. [Univ. of Dusseldorf, Medical Faculty, Dept. of Diagnostic and Interventional Radiology, Dusseldorf (Germany)

    2012-06-15

    Background: The diagnostic accuracy of FDG-PET/CT for the detection of axillary lymph node metastases in breast cancer patients acquired 60 min after FDG administration is reported to be only moderate, especially due to low sensitivity. Purpose: To test whether a delayed scan 90 min after FDG administration could enhance the diagnostic accuracy of FDG-PET/CT for the detection of axillary lymph node metastases. Material and Methods: Thirty-eight women suffering from primary breast cancer (mean age 52 years; range 25-78 years; standard deviation 14 years) underwent a pre-therapeutic dual-time-point FDG-PET/CT scan. The maximum standardized uptake value (SUVmax) of axillary lymph nodes was measured at two different time points (time point T1: 60 min after FDG injection, time point T2: 90 min after FDG injection). SUVmax of axillary lymph nodes at T1 and T2 were assessed for statistical significance using a paired Wilcoxon-Test (P < 0.05). At T1 a qualitative analysis of the FDG-PET/CT scan was performed to define physiologic and metastatic lymph nodes. At T2 an increase of the SUVmax of at least 3.75% over time was rated as indicating malignancy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the accuracy of FDG-PET/CT for the detection of axillary lymph node metastases was calculated at time points T1 and T2. Statistically significant differences were determined using Fisher's exact test (P < 0.05). Histopathology served as the standard of reference. A compartment based analysis was done. Results: Axillary lymph nodes had a mean SUVmax of 1.6 (range 0.6-10.8; SD 1.9) at T1 and a mean SUVmax of 1.8 (range 0.5-17.9; SD 3.5) at T2. This difference was statistically significant (P = 0.047). The sensitivity, specificity, PPV, NPV, and accuracy of FDG-PET/CT for the detection of axillary lymph node metastases was 81%, 100%, 100%, 88%, and 92% at T1, and 88%, 50%, 56%, 85%, and 66% at T2, respectively. This

  14. Image quality, radiation dose and diagnostic accuracy of 70 kVp whole brain volumetric CT perfusion imaging: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Xiao Kun; Ni, Qian Qian; Zhou, Chang Sheng; Chen, Guo Zhong; Luo, Song; Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Schoepf, U.J. [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Medical University of South Carolina, Ashley River Tower, Division of Cardiovascular Imaging, Charleston, SC (United States); Fuller, Stephen R.; De Cecco, Carlo N. [Medical University of South Carolina, Ashley River Tower, Division of Cardiovascular Imaging, Charleston, SC (United States)

    2016-11-15

    To evaluate image quality and diagnostic accuracy for acute infarct detection and radiation dose of 70 kVp whole brain CT perfusion (CTP) and CT angiography (CTA) reconstructed from CTP source data. Patients were divided into three groups (n = 50 each): group A, 80 kVp, 21 scanning time points; groups B, 70 kVp, 21 scanning time points; group C, 70 kVp, 17 scanning time points. Objective and subjective image quality of CTP and CTA were compared. Diagnostic accuracy for detecting acute infarct and cerebral artery stenosis ≥ 50 % was calculated for CTP and CTA with diffusion weighted imaging and digital subtraction angiography as reference standards. Effective radiation dose was compared. There were no differences in any perfusion parameter value between three groups (P > 0.05). No difference was found in subjective image quality between three groups (P > 0.05). Diagnostic accuracy for detecting acute infarct and vascular stenosis showed no difference between three groups (P > 0.05). Compared with group A, radiation doses of groups B and C were decreased by 28 % and 37 % (both P < 0.001), respectively. Compared with 80 kVp protocol, 70 kVp brain CTP allows comparable vascular and perfusion assessment and lower radiation dose while maintaining high diagnostic accuracy in detecting acute infarct. (orig.)

  15. Diagnostic accuracy of coronary CT angiography using 3{sup rd}-generation dual-source CT and automated tube voltage selection: Clinical application in a non-obese and obese patient population

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Caruso, Damiano [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Tesche, Christian [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Heart Centre Munich-Bogenhausen, Department of Cardiology, Munich (Germany); Steinberg, Daniel H.; Bayer, Richard R. [Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Varga-Szemes, Akos; Stubenrauch, Andrew C.; Biancalana, Matthew; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2017-06-15

    To investigate diagnostic accuracy of 3{sup rd}-generation dual-source CT (DSCT) coronary angiography in obese and non-obese patients. We retrospectively analyzed 76 patients who underwent coronary CT angiography (CCTA) and invasive coronary angiography. Prospectively ECG-triggered acquisition was performed with automated tube voltage selection (ATVS). Patients were dichotomized based on body mass index in groups A (<30 kg/m{sup 2}, n = 37) and B (≥30 kg/m{sup 2}, n = 39) and based on tube voltage in groups C (<120 kV, n = 46) and D (120 kV, n = 30). Coronary arteries were assessed for significant stenoses (≥50 % luminal narrowing) and diagnostic accuracy was calculated. Per-patient overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 96.9 %, 95.5 %, 93.9 %, 97.7 % and 96.1 %, respectively. Sensitivity and NPV were lower in groups B and D compared to groups A and C, but no statistically significant differences were observed (group A vs. B: sensitivity, 100.0 % vs. 93.3 %, p = 0.9493; NPV, 100 % vs. 95.5 %, p = 0.9812; group C vs. D: sensitivity, 100.0 % vs. 92.3 %, p = 0.8462; NPV, 100.0 % vs. 94.1 %, p = 0.8285). CCTA using 3{sup rd}-generation DSCT and (ATVS) provides high diagnostic accuracy in both non-obese and obese patients. (orig.)

  16. Medical CT image reconstruction accuracy in the presence of metal objects using x-rays up to 1 MeV with x-ray targets of beryllium, carbon, aluminum, copper, and tungsten

    Science.gov (United States)

    Clayton, James; Ganguly, Arundhuti; Virshup, Gary

    2012-04-01

    Flat panels imagers based on amorphous silicon technology (a-Si) for digital radiography have been accepted by the medical community as having several advantages over film-based systems. Radiotherapy treatment planning systems employ computed tomographic (CT) data sets and projection images to delineate tumor targets and normal structures that are to be spared from radiation treatment. The accuracy of CT numbers is crucial for radiotherapy dose calculations. Conventional CT scanners operating at kilovoltage X-ray energies typically exhibit significant image reconstruction artifacts in the presence of metal implants in human body. Megavoltage X-ray energies have problems maintaining contrast sensitivity for the same dose as kV X-ray systems. We intend to demonstrate significant improvement in metal artifact reductions and electron density measurements using an amorphous silicon a-Si imager obtained with an X-ray source that can operate at energies up to 1 MeV. We will investigate the ability to maintain contrast sensitivity at this higher X-ray energy by using targets with lower atomic numbers and appropriate amounts of Xray filtration than are typically used as X-ray production targets and filters.

  17. Diagnostic Accuracy of 18F-FDG PET/CT in Infective Endocarditis and Implantable Cardiac Electronic Device Infection: A Cross-Sectional Study.

    Science.gov (United States)

    Granados, Ulises; Fuster, David; Pericas, Juan M; Llopis, Jaime L; Ninot, Salvador; Quintana, Eduard; Almela, Manel; Paré, Carlos; Tolosana, José M; Falces, Carlos; Moreno, Asuncion; Pons, Francesca; Lomeña, Francisco; Miro, Jose M

    2016-11-01

    Early diagnosis of infective endocarditis (IE) is based on the yielding of blood cultures and echocardiographic findings. However, they have limitations and sometimes the diagnosis is inconclusive, particularly in patients with prosthetic valves (PVs) and implantable cardiac electronic devices (ICEDs). The primary aim of this study was to evaluate the diagnostic accuracy of (18)F-FDG PET/CT in patients with suspected IE and ICED infection. A prospective study with 80 consecutive patients with suspected IE and ICED infection (65 men and 15 women with a mean age of 68 ± 13 y) between June 2013 and May 2015 was performed in our hospital. The inclusion criteria were clinically suspected IE and ICED infection at the following locations: native valve (NV) (n = 21), PV (n = 29), or ICED (n = 30) (automatic implantable defibrillator [n = 11] or pacemaker [n = 19]). Whole-body (18)F-FDG PET/CT with a myocardial uptake suppression protocol with unfractionated heparin was performed in all patients. The final diagnosis of infection was established by the IE Study Group according to the clinical, echocardiographic, and microbiologic findings. A final diagnosis of infection was confirmed in 31 patients: NV (n = 6), PV (n = 12), and ICED (n = 13). Sensitivity, specificity, positive predictive value, and negative predictive value for (18)F-FDG PET/CT were 82%, 96%, 94%, and 87%, respectively. (18)F-FDG PET/CT was false-negative in all cases with infected NV. (18)F-FDG PET/CT was able to reclassify 63 of 70 (90%) patients initially classified as possible IE by modified Duke criteria. In 18 of 70 cases, (18)F-FDG PET/CT changed possible to definite IE (26%) and in 45 of 70 cases changed possible to rejected IE (64%). Additionally, (18)F-FDG PET/CT identified 8 cases of septic embolism and 3 of colorectal cancer in patients with a final diagnosis of IE. (18)F-FDG PET/CT proved to be a useful diagnostic tool in suspected IE and ICED infection and should be included in the diagnostic

  18. Pancreatic neuroendocrine tumour (PNET): Staging accuracy of MDCT and its diagnostic performance for the differentiation of PNET with uncommon CT findings from pancreatic adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Hoon; Lee, Jeong Min; Han, Joon Koo; Choi, Byung-Ihn [Seoul National University Hospital, Department of Radiology, 101 Daehangno, Jongno-gu, Seoul (Korea, Republic of); Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul (Korea, Republic of); Eun, Hyo Won [Yonsei University College of Medicine, Department of Radiology, Severance Hospital, Seodaemun-ku, Seoul (Korea, Republic of); Kim, Young Jae [Soonchunhyang University Hospital, Department of Radiology, 657 Hannam-Dong, Youngsan-Ku, Seoul (Korea, Republic of)

    2016-05-15

    To investigate staging accuracy of multidetector CT (MDCT) for pancreatic neuroendocrine tumour (PNET) and diagnostic performance for differentiation of PNET from pancreatic adenocarcinoma. We included 109 patients with surgically proven PNET (NETG1 = 66, NETG2 = 31, NEC = 12) who underwent MDCT. Two reviewers assessed stage and presence of predefined CT findings. We analysed the relationship between CT findings and tumour grade. Using PNETs with uncommon findings, we also estimated the possibility of PNET or adenocarcinoma. Accuracy for T stage was 85-88 % and N-metastasis was 83-89 %. Common findings included well circumscribed, homogeneously enhanced, hypervascular mass, common in lower grade tumours (p < 0.05). Uncommon findings included ill-defined, heterogeneously enhanced, hypovascular mass and duct dilation, common in higher grade tumours (p < 0.05). Using 31 PNETs with uncommon findings, diagnostic performance for differentiation from adenocarcinoma was 0.760-0.806. Duct dilatation was an independent predictor for adenocarcinoma (Exp(B) = 4.569). PNETs with uncommon findings were associated with significantly worse survival versus PNET with common findings (62.7 vs. 95.7 months, p < 0.001). MDCT is useful for preoperative evaluation of PNET; it not only accurately depicts the tumour stage but also prediction of tumour grade, because uncommon findings were more common in higher grade tumours. (orig.)

  19. A new method to measure electron density and effective atomic number using dual-energy CT images

    Science.gov (United States)

    Ramos Garcia, Luis Isaac; Pérez Azorin, José Fernando; Almansa, Julio F.

    2016-01-01

    The purpose of this work is to present a new method to extract the electron density ({ρ\\text{e}} ) and the effective atomic number (Z eff) from dual-energy CT images, based on a Karhunen-Loeve expansion (KLE) of the atomic cross section per electron. This method was used to calibrate a Siemens Definition CT using the CIRS phantom. The predicted electron density and effective atomic number using 80 kVp and 140 kVp were compared with a calibration phantom and an independent set of samples. The mean absolute deviations between the theoretical and calculated values for all the samples were 1.7 %  ±  0.1 % for {ρ\\text{e}} and 4.1 %  ±  0.3 % for Z eff. Finally, these results were compared with other stoichiometric method. The application of the KLE to represent the atomic cross section per electron is a promising method for calculating {ρ\\text{e}} and Z eff using dual-energy CT images.

  20. The diagnostic accuracy of US, CT, MRI and {sup 1}H-MRS for the evaluation of hepatic steatosis compared with liver biopsy: a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bohte, Anneloes E.; Werven, Jochem R. van; Bipat, Shandra; Stoker, Jaap [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands)

    2011-01-15

    To meta-analyse the diagnostic accuracy of US, CT, MRI and {sup 1}H-MRS for the evaluation of hepatic steatosis. From a comprehensive literature search in MEDLINE, EMBASE, CINAHL and Cochrane (up to November 2009), articles were selected that investigated the diagnostic performance imaging techniques for evaluating hepatic steatosis with histopathology as the reference standard. Cut-off values for the presence of steatosis on liver biopsy were subdivided into four groups: (1) >0, >2 and >5% steatosis; (2) >10, >15 and >20%; (3) >25, >30 and >33%; (4) >50, >60 and >66%. Per group, summary estimates for sensitivity and specificity were calculated. The natural-logarithm of the diagnostic odds ratio (lnDOR) was used as a single indicator of test performance. 46 articles were included. Mean sensitivity estimates for subgroups were 73.3-90.5% (US), 46.1-72.0% (CT), 82.0-97.4% (MRI) and 72.7-88.5% ({sup 1}H-MRS). Mean specificity ranges were 69.6-85.2% (US), 88.1-94.6% (CT), 76.1-95.3% (MRI) and 92.0-95.7% ({sup 1}H-MRS). Overall performance (lnDOR) of MRI and {sup 1}H-MRS was better than that for US and CT for all subgroups, with significant differences in groups 1 and 2. MRI and {sup 1}H-MRS can be considered techniques of choice for accurate evaluation of hepatic steatosis. (orig.)

  1. Comparison of the Accuracy and Performance of Different Numbers of Classes in Discretised Solution Method for Population Balance Model

    Directory of Open Access Journals (Sweden)

    Zhenliang Li

    2016-01-01

    Full Text Available One way of solving population balance model (PBM in a time efficient way is by means of discretisation of the population property of interest. A computational grid, for example, vi+1=kvi (vi is the volume of particle in class i, could be used to classify the particles in discretisation techniques. However, there are still disagreements in the appropriate number of classes divided by the grids. In this study, the different numbers of classes for solving PBM were compared in terms of accuracy and performance to describe the particle size distribution (PSD from the flocculation of activated sludge. It is found that the simulated PSDs are similar to the experimental data for all the geometric grids (vi+1:vi≤2, and there is no obvious difference among the values of calibrated parameter, ratio of breakage rate coefficient and collision efficiency, for each velocity gradient. However, the simulation results with less error could be obtained with larger number of classes, and more computational times, which show exponential relationship with the number of classes, are needed. Considering numerical accuracy and efficiency, the classes 35 or a geometric grid with factor 1.6, aligning with the Fibonacci sequence (vi+vi-1≈vi+1, is recommended for the particles in the size range of 5.5~1086 μm.

  2. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    DEFF Research Database (Denmark)

    Zimmermann, S. J.; Rowshanfarzad, P.; Ebert, M. A.

    2015-01-01

    radiation isocentre prior to routine use of the cone-beam CT system. The isocentre determination method used in the XVI software is not available to users. The aim of this work is to perform an independent evaluation of the Elekta XVI 4.5 software for isocentre verification with focus on the robustness......Purpose/Objective: Most modern radiotherapy treatments are based on cone-beam CT images to ensure precise positioning of the patient relative to the linac. This requires alignment of the cone-beam CT system to the linac MV radiation isocentre. Therefore, it is important to precisely localize the MV......) and the radiation field centre (RFC) is calculated. A software package was developed for accurate calculation of the linac isocentre position. This requires precise determination of the position of the ball bearing and the RFC. Results: Data were acquired for 6 MV, 18 MV and flattening filter free (FFF) 6 MV FFF...

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

    Energy Technology Data Exchange (ETDEWEB)

    Dolezel, Martin, E-mail: dolezelm@email.cz [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); First Faculty of Medicine, Charles University, Prague (Czech Republic); Odrazka, Karel [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); First Faculty of Medicine, Charles University, Prague (Czech Republic); Zizka, Jan [Department of Radiology, Charles University Teaching Hospital, Hradec Kralove (Czech Republic); Vanasek, Jaroslav; Kohlova, Tereza; Kroulik, Tomas [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); Spitzer, Dusan; Ryska, Pavel [Department of Radiology, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); Tichy, Michal; Kostal, Milan [Department of Gynaecology, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic); Jalcova, Lubica [Oncology Centre, Multiscan and Pardubice Regional Hospital, Pardubice (Czech Republic)

    2012-09-01

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

  4. Dual-energy CT angiography in peripheral arterial occlusive disease - accuracy of maximum intensity projections in clinical routine and subgroup analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kau, Thomas [Klinikum Klagenfurt, General Hospital of Klagenfurt, Institute of Diagnostic and Interventional Radiology, Klagenfurt (Austria); Klinikum Klagenfurt am Worthersee, Radiologie, Klagenfurt (Austria); Eicher, Wolfgang; Reiterer, Christian; Niedermayer, Martin; Rabitsch, Egon; Hausegger, Klaus A. [Klinikum Klagenfurt, General Hospital of Klagenfurt, Institute of Diagnostic and Interventional Radiology, Klagenfurt (Austria); Senft, Birgit [Section of Statistics, Reha Clinic for Mental Health, Klagenfurt (Austria)

    2011-08-15

    To evaluate the accuracy of dual-energy CT angiography (DE-CTA) maximum intensity projections (MIPs) in symptomatic peripheral arterial occlusive disease (PAOD). In 58 patients, DE-CTA of the lower extremities was performed on dual-source CT. In a maximum of 35 arterial segments, severity of the most stenotic lesion was graded (<10%, 10-49% and 50-99% luminal narrowing or occlusion) independently by two radiologists, with DSA serving as the reference standard. In DSA, 52.3% of segments were significantly stenosed or occluded. Agreement of DE-CTA MIPs with DSA was good in the aorto-iliac and femoro-popliteal regions ({kappa} = 0.72; {kappa} = 0.66), moderate in the crural region ({kappa} = 0.55), slight in pedal arteries ({kappa} = 0.10) and very good in bypass segments ({kappa} = 0.81). Accuracy was 88%, 78%, 74%, 55% and 82% for the respective territories and moderate (75%) overall, with good sensitivity (84%) and moderate specificity (67%). Sensitivity and specificity was 82% and 76% in claudicants and 84% and 61% in patients with critical limb ischaemia. While correlating well with DSA above the knee, accuracy of DE-CTA MIPs appeared to be moderate in the calf and largely insufficient in calcified pedal arteries, especially in patients with critical limb ischaemia. (orig.)

  5. Assessment of image quality and dose calculation accuracy on kV CBCT, MV CBCT, and MV CT images for urgent palliative radiotherapy treatments.

    Science.gov (United States)

    Held, Mareike; Cremers, Florian; Sneed, Penny K; Braunstein, Steve; Fogh, Shannon E; Nakamura, Jean; Barani, Igor; Perez-Andujar, Angelica; Pouliot, Jean; Morin, Olivier

    2016-03-08

    A clinical workflow was developed for urgent palliative radiotherapy treatments that integrates patient simulation, planning, quality assurance, and treatment in one 30-minute session. This has been successfully tested and implemented clinically on a linac with MV CBCT capabilities. To make this approach available to all clin-ics equipped with common imaging systems, dose calculation accuracy based on treatment sites was assessed for other imaging units. We evaluated the feasibility of palliative treatment planning using on-board imaging with respect to image quality and technical challenges. The purpose was to test multiple systems using their commercial setup, disregarding any additional in-house development. kV CT, kV CBCT, MV CBCT, and MV CT images of water and anthropomorphic phantoms were acquired on five different imaging units (Philips MX8000 CT Scanner, and Varian TrueBeam, Elekta VersaHD, Siemens Artiste, and Accuray Tomotherapy linacs). Image quality (noise, contrast, uniformity, spatial resolution) was evaluated and compared across all machines. Using individual image value to density calibrations, dose calculation accuracies for simple treatment plans were assessed for the same phantom images. Finally, image artifacts on clinical patient images were evaluated and compared among the machines. Image contrast to visualize bony anatomy was sufficient on all machines. Despite a high noise level and low contrast, MV CT images provided the most accurate treatment plans relative to kV CT-based planning. Spatial resolution was poorest for MV CBCT, but did not limit the visualization of small anatomical structures. A comparison of treatment plans showed that monitor units calculated based on a prescription point were within 5% difference relative to kV CT-based plans for all machines and all studied treatment sites (brain, neck, and pelvis). Local dose differences > 5% were found near the phantom edges. The gamma index for 3%/3 mm criteria was ≥ 95% in most

  6. Improved dose calculation accuracy for low energy brachytherapy by optimizing dual energy CT imaging protocols for noise reduction using sinogram affirmed iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Guillaume [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); Munich Univ. (Germany). Dept. of Medical Physics; Gaudreault, Mathieu [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); Laval Univ., QC (Canada). Dept. de Radio-Oncologie et Centre de Recherche en Cancerologie; Laval Univ., QC (Canada). Dept. de Physique, de Genie Physique et d' Optique; Elmpt, Wouter van [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); Wildberger, Joachim E. [Maastricht University Medical Center (Netherlands). Dept. of Radiology; Verhaegen, Frank [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); McGill Univ. Montreal, QC (Canada). Dept. of Oncology

    2016-05-01

    The goal of this study was to evaluate the noise reduction achievable from dual energy computed tomography (CT) imaging (DECT) using filtered backprojection (FBP) and iterative image reconstruction algorithms combined with increased imaging exposure. We evaluated the data in the context of imaging for brachytherapy dose calculation, where accurate quantification of electron density ρ{sub e} and effective atomic number Z{sub eff} is beneficial. A dual source CT scanner was used to scan a phantom containing tissue mimicking inserts. DECT scans were acquired at 80 kVp/140Sn kVp (where Sn stands for tin filtration) and 100 kVp/140Sn kVp, using the same values of the CT dose index CTDI{sub vol} for both settings as a measure for the radiation imaging exposure. Four CTDI{sub vol} levels were investigated. Images were reconstructed using FBP and sinogram affirmed iterative reconstruction (SAFIRE) with strength 1,3 and 5. From DECT scans two material quantities were derived, Z{sub eff} and ρ{sub e}. DECT images were used to assign material types and the amount of improperly assigned voxels was quantified for each protocol. The dosimetric impact of improperly assigned voxels was evaluated with Geant4 Monte Carlo (MC) dose calculations for an {sup 125}I source in numerical phantoms. Standard deviations for Z{sub eff} and ρ{sub e} were reduced up to a factor ∝2 when using SAFIRE with strength 5 compared to FBP. Standard deviations on Z{sub eff} and ρ{sub e} as low as 0.15 and 0.006 were achieved for the muscle insert representing typical soft tissue using a CTDI{sub vol} of 40 mGy and 3 mm slice thickness. Dose calculation accuracy was generally improved when using SAFIRE. Mean (maximum absolute) dose errors of up to 1.3% (21%) with FBP were reduced to less than 1% (6%) with SAFIRE at a CTDI{sub vol} of 10 mGy. Using a CTDI{sub vol} of 40mGy and SAFIRE yielded mean dose calculation errors of the order of 0.6% which was the MC dose calculation precision in this study and

  7. Noise-Optimized Virtual Monoenergetic Dual-Energy CT Improves Diagnostic Accuracy for the Detection of Active Arterial Bleeding of the Abdomen.

    Science.gov (United States)

    Martin, Simon S; Wichmann, Julian L; Scholtz, Jan-Erik; Leithner, Doris; D'Angelo, Tommaso; Weyer, Hendrik; Booz, Christian; Lenga, Lukas; Vogl, Thomas J; Albrecht, Moritz H

    2017-09-01

    To evaluate diagnostic accuracy of a noise-optimized virtual monoenergetic imaging (VMI+) reconstruction technique for detection of active arterial abdominal bleeding on dual-energy (DE) CT angiography compared with standard image reconstruction. DE CT angiography data sets of 71 patients (46 men; age 63.6 y ± 13.3) with suspected arterial bleeding of the abdomen or pelvis were reconstructed with standard linearly blended (F_0.5), VMI+, and traditional virtual monoenergetic imaging (VMI) algorithms in 10-keV increments from 40 to 100 keV. Attenuation measurements were performed in the descending aorta, area of hemorrhage, and feeding artery to calculate contrast-to-noise ratios (CNRs) in patients with active arterial bleeding. Based on quantitative image quality results, the best series for each reconstruction technique were chosen to analyze the diagnostic performance of 3 blinded radiologists. DE CT angiography showed acute arterial bleeding in 36 patients. Mean CNR was superior in 40-keV VMI+ compared with VMI series (all P VMI and F_0.5 (21.6 ± 7.9, 12.9 ± 4.7, and 10.4 ± 3.6) images. Area under the curve analysis for detection of arterial bleeding showed significantly superior (P VMI+ (0.963) compared with 70-keV VMI (0.775) and F_0.5 (0.817) series. Diagnostic accuracy in patients with active arterial bleeding of the abdomen can be significantly improved using VMI+ reconstructions at 40 keV compared with standard linearly blended and traditional VMI series in DE CT angiography. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

  8. A dual centre study of setup accuracy for thoracic patients based on Cone-Beam CT data

    DEFF Research Database (Denmark)

    Nielsen, Tine B; Hansen, Vibeke N; Westberg, Jonas;

    2011-01-01

    BACKGROUND AND PURPOSE: To compare setup uncertainties at two different institutions by using identical imaging and analysis techniques for thoracic patients with different fixation equipments. METHODS AND MATERIALS: Patient registration results from Cone-Beam CT (CBCT) scans of 174 patients were...

  9. Optimization of the Coverage and Accuracy of an Indoor Positioning System with a Variable Number of Sensors.

    Science.gov (United States)

    Domingo-Perez, Francisco; Lazaro-Galilea, Jose Luis; Bravo, Ignacio; Gardel, Alfredo; Rodriguez, David

    2016-06-22

    This paper focuses on optimal sensor deployment for indoor localization with a multi-objective evolutionary algorithm. Our goal is to obtain an algorithm to deploy sensors taking the number of sensors, accuracy and coverage into account. Contrary to most works in the literature, we consider the presence of obstacles in the region of interest (ROI) that can cause occlusions between the target and some sensors. In addition, we aim to obtain all of the Pareto optimal solutions regarding the number of sensors, coverage and accuracy. To deal with a variable number of sensors, we add speciation and structural mutations to the well-known non-dominated sorting genetic algorithm (NSGA-II). Speciation allows one to keep the evolution of sensor sets under control and to apply genetic operators to them so that they compete with other sets of the same size. We show some case studies of the sensor placement of an infrared range-difference indoor positioning system with a fairly complex model of the error of the measurements. The results obtained by our algorithm are compared to sensor placement patterns obtained with random deployment to highlight the relevance of using such a deployment algorithm.

  10. Accuracy and Utility of Deformable Image Registration in {sup 68}Ga 4D PET/CT Assessment of Pulmonary Perfusion Changes During and After Lung Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, Nicholas, E-mail: nick.hardcastle@gmail.com [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong (Australia); Hofman, Michael S. [Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne (Australia); Hicks, Rodney J. [Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne (Australia); Department of Medicine, University of Melbourne, Melbourne (Australia); Callahan, Jason [Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne (Australia); Kron, Tomas [Department of Medical Imaging and Radiation Sciences, Monash University, Clayton (Australia); The Sir Peter MacCallum Department of Oncology, Melbourne University, Victoria (Australia); MacManus, Michael P.; Ball, David L. [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); The Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne (Australia); Jackson, Price [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne (Australia); Siva, Shankar [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia)

    2015-09-01

    Purpose: Measuring changes in lung perfusion resulting from radiation therapy dose requires registration of the functional imaging to the radiation therapy treatment planning scan. This study investigates registration accuracy and utility for positron emission tomography (PET)/computed tomography (CT) perfusion imaging in radiation therapy for non–small cell lung cancer. Methods: {sup 68}Ga 4-dimensional PET/CT ventilation-perfusion imaging was performed before, during, and after radiation therapy for 5 patients. Rigid registration and deformable image registration (DIR) using B-splines and Demons algorithms was performed with the CT data to obtain a deformation map between the functional images and planning CT. Contour propagation accuracy and correspondence of anatomic features were used to assess registration accuracy. Wilcoxon signed-rank test was used to determine statistical significance. Changes in lung perfusion resulting from radiation therapy dose were calculated for each registration method for each patient and averaged over all patients. Results: With B-splines/Demons DIR, median distance to agreement between lung contours reduced modestly by 0.9/1.1 mm, 1.3/1.6 mm, and 1.3/1.6 mm for pretreatment, midtreatment, and posttreatment (P<.01 for all), and median Dice score between lung contours improved by 0.04/0.04, 0.05/0.05, and 0.05/0.05 for pretreatment, midtreatment, and posttreatment (P<.001 for all). Distance between anatomic features reduced with DIR by median 2.5 mm and 2.8 for pretreatment and midtreatment time points, respectively (P=.001) and 1.4 mm for posttreatment (P>.2). Poorer posttreatment results were likely caused by posttreatment pneumonitis and tumor regression. Up to 80% standardized uptake value loss in perfusion scans was observed. There was limited change in the loss in lung perfusion between registration methods; however, Demons resulted in larger interpatient variation compared with rigid and B-splines registration

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y [University of Kansas Hospital, Kansas City, KS (United States); Fullerton, G; Goins, B [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States)

    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

  12. Does {sup 18}F-FDG PET/CT add diagnostic accuracy in incidentally identified non-secreting adrenal tumours?

    Energy Technology Data Exchange (ETDEWEB)

    Tessonnier, L.; Colavolpe, C.; Mundler, O.; Taieb, D. [Centre Hospitalo-Universitaire de la Timone, Service Central de Biophysique et de Medecine Nucleaire, Marseille Cedex 5 (France); Sebag, F.; Palazzo, F.F.; Henry, J.F. [Centre Hospitalo-Universitaire de la Timone, Service de Chirurgie Generale et Endocrinienne, Marseille Cedex 5 (France); Micco, C. de [Centre Hospitalo-Universitaire de la Timone, Faculte de Medecine, Institut National de la Sante et de la Recherche Medicale (U555), Marseille Cedex 5 (France); Mancini, J. [Centre Hospitalo-Universitaire de la Timone, Service de Sante Publique et d' Information Medicale, Marseille Cedex 5 (France); Conte-Devolx, B. [Centre Hospitalo-Universitaire de la Timone, Service d' Endocrinologie, Diabete et des Maladies Metaboliques, Marseille Cedex 5 (France)

    2008-11-15

    The widespread use of high-resolution cross-sectional imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) for the investigation of the abdomen is associated with an increasing detection of incidental adrenal masses. We evaluated the ability of {sup 18}F-fluorodeoxyglucose positron emission tomography to distinguish benign from malignant adrenal masses when CT or MRI results had been inconclusive. We included only patients with no evidence of hormonal hypersecretion and no personal history of cancer or in whom previously diagnosed cancer was in prolonged remission. PET/CT scans were acquired after 90 min (mean, range 60-140 min) after FDG injection. The visual interpretation, maximum standardised uptake values (SUVmax) and adrenal compared to liver uptake ratio were correlated with the final histological diagnosis or clinico-radiological follow-up when surgery had not been performed. Thirty-seven patients with 41 adrenal masses were prospectively evaluated. The final diagnosis was 12 malignant, 17 benign tumours, and 12 tumours classified as benign on follow-up. The visual interpretation was more accurate than SUVmax alone, tumour diameter or unenhanced density, with a sensitivity of 100% (12/12), a specificity of 86% (25/29) and a negative predictive value of 100% (25/25). The use of 1.8 as the threshold for tumour/liver SUVmax ratio, retrospectively established, demonstrated 100% sensitivity and specificity. FDG PET/CT accurately characterises adrenal tumours, with an excellent sensitivity and negative predictive values. Thus, a negative PET may predict a benign tumour that would potentially prevent the need for surgery of adrenal tumours with inconclusive conventional imaging. (orig.)

  13. CTC-ask: a new algorithm for conversion of CT numbers to tissue parameters for Monte Carlo dose calculations applying DICOM RS knowledge

    DEFF Research Database (Denmark)

    Ottosson, Rickard; Behrens, Claus F.

    2011-01-01

    One of the building blocks in Monte Carlo (MC) treatment planning is to convert patient CT data to MC compatible phantoms, consisting of density and media matrices. The resulting dose distribution is highly influenced by the accuracy of the conversion. Two major contributing factors are precise c...

  14. Sensitivity and accuracy of volumetry of pulmonary nodules on low-dose 16- and 64-row multi-detector CT: an anthropomorphic phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Xueqian; Zhao, Yingru; Ooijen, Peter M.A. van; Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Department of Radiology, EB44, P.O. Box 30.001, Groningen (Netherlands); University of Groningen, University Medical Center Groningen, Center for Medical Imaging-North East Netherlands, Department of Radiology, Groningen (Netherlands); Snijder, Roland A.; Greuter, Marcel J.W. [University of Groningen, University Medical Center Groningen, Department of Radiology, EB44, P.O. Box 30.001, Groningen (Netherlands); Jong, Pim A. de [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Oudkerk, Matthijs [University of Groningen, University Medical Center Groningen, Center for Medical Imaging-North East Netherlands, Department of Radiology, Groningen (Netherlands); Bock, Geertruida H. de [University of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen (Netherlands)

    2013-01-15

    To assess the sensitivity of detection and accuracy of volumetry by manual and semi-automated quantification of artificial pulmonary nodules in an anthropomorphic thoracic phantom on low-dose CT. Fifteen artificial spherical nodules (diameter 3, 5, 8, 10 and 12 mm; CT densities -800, -630 and +100 HU) were randomly placed inside an anthropomorphic thoracic phantom. The phantom was examined on 16- and 64-row multidetector CT with a low-dose protocol. Two independent blinded observers screened for pulmonary nodules. Nodule diameter was measured manually, and volume calculated. For solid nodules (+100 HU), diameter and volume were also evaluated by semi-automated software. Differences in observed volumes between the manual and semi-automated method were evaluated by a t-test. Sensitivity was 100 % for all nodules of >5 mm and larger, 60-80 % for solid and 0-20 % for non-solid 3-mm nodules. No false-positive nodules but high inter-observer reliability and inter-technique correlation were found. Volume was underestimated manually by 24.1 {+-} 14.0 % for nodules of any density, and 26.4 {+-} 15.5 % for solid nodules, compared with 7.6 {+-} 8.5 % (P < 0.01) semi-automatically. In an anthropomorphic phantom study, the sensitivity of detection is 100 % for nodules of >5 mm in diameter. Semi-automated volumetry yielded more accurate nodule volumes than manual measurements. (orig.)

  15. {sup 18}F-Fluorocholine PET/CT as a complementary tool in the follow-up of low-grade glioma: diagnostic accuracy and clinical utility

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Rio, Manuel; Rodriguez-Fernandez, Antonio; Llamas-Elvira, Jose M. [Instituto de Investigacion Biosanitaria de Granada, Granada (Spain); University Hospital ' ' Virgen de las Nieves' ' , Department of Nuclear Medicine, Granada (Spain); Testart Dardel, Nathalie [University Hospital ' ' Virgen de las Nieves' ' , Department of Nuclear Medicine, Granada (Spain); Santiago Chinchilla, Alicia [University Hospital ' ' Virgen de las Nieves' ' , Department of Radiology, Granada (Spain); Olivares Granados, Gonzalo [University Hospital ' ' Virgen de las Nieves' ' , Department of Neurosurgery, Granada (Spain); Luque Caro, Raquel [University Hospital ' ' Virgen de las Nieves' ' , Department of Medical Oncology, Granada (Spain); Zurita Herrera, Mercedes [University Hospital ' ' Virgen de las Nieves' ' , Department of Radiotherapy Oncology, Granada (Spain); Chamorro Santos, Clara E. [University Hospital ' ' Virgen de las Nieves' ' , Department of Pathology, Granada (Spain); Lardelli-Claret, Pablo [Instituto de Investigacion Biosanitaria de Granada, Granada (Spain); Centros de Investigacion Biomedica en Red de Epidemiologia y Salud Publica (CIBERESP), Granada (Spain); University of Granada, Department of Preventive Medicine and Public Health, School of Medicine, Granada (Spain)

    2015-05-01

    The follow-up of treated low-grade glioma (LGG) requires the evaluation of subtle clinical changes and MRI results. When the result is inconclusive, additional procedures are required to assist decision-making, such as the use of advanced MRI (aMRI) sequences and nuclear medicine scans (SPECT and PET). The aim of this study was to determine whether incorporating {sup 18}F-fluorocholine PET/CT in the follow-up protocol for treated LGG improves diagnostic accuracy and clinical utility. This was a prospective case-series study in patients with treated LGG during standard follow-up with indeterminate clinical and/or radiological findings of tumour activity. All patients underwent clinical evaluation, aMRI, {sup 201}Tl-SPECT and {sup 18}F-fluorocholine PET/CT. Images were interpreted by visual evaluation complemented with semiquantitative analysis. Between January 2012 and December 2013, 18 patients were included in this study. The final diagnosis was established by histology (five surgical specimens, one biopsy specimen) or by consensus of the Neuro-Oncology Group (11 patients) after a follow-up of >6 months (mean 14.9 ± 2.72 months). The global diagnostic accuracies were 90.9 % for aMRI (38.8 % inconclusive), 69.2 % for {sup 201}Tl-SPECT (11.1 % inconclusive), and 100 % for {sup 18}F-fluorocholine PET/CT. {sup 201}Tl-SPECT led correctly to a change in the initial approach in 38.9 % of patients but might have led to error in 27.8 %. The use of {sup 18}F-fluorocholine PET/CT alone rather than {sup 201}Tl-SPECT led correctly to a change in the approach suggested by routine follow-up in 72.2 % of patients and endorsed the approach in the remaining 27.8 %. Our results support the need to complement structural MRI with aMRI and nuclear medicine procedures in selected patients. {sup 18}F-Fluorocholine PET/CT can be useful in the individualized management of patients with treated LGG with uncertain clinical and/or radiological evidence of tumour activity. (orig.)

  16. Feasibility of 320-row area detector CT coronary angiography using 40 mL of contrast material: assessment of image quality and diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Rihyeon; Park, Eun-Ah; Lee, Whal; Chung, Jin Wook [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of)

    2016-11-15

    To assess the image quality and diagnostic accuracy of 320-row area detector CT (320-ADCT) coronary angiography using 40 mL of contrast material in comparison with 60-mL protocol. This retrospective study included 183 patients who underwent 320-ADCT coronary angiography using 40 mL of contrast and additional 183 sex- and body mass index-matched patients using 60 mL of contrast constituting the control group. Both groups used the same 5-mL/sec injection rate. Quantitative image quality measurements and diagnostic accuracies were calculated and compared. Mean attenuation and contrast-to-noise ratio (CNR) at the aorta and all coronary arteries were lower in the 40-mL group than in the 60-mL group (all, p < 0.05), except for the CNR at proximal coronary arteries at 100 kVp (p = 0.073). However, the proportion of coronary segments with vessel attenuation >250 HU was not different between groups (all, p > 0.05), except for distal coronary arteries at 80 kVp (p = 0.001). Furthermore, there were no differences in per-patient and per-segment diagnostic accuracies between the groups (all, p > 0.05). 320-ADCT coronary angiography using 40 mL of contrast showed image quality and diagnostic accuracy comparable to the 60-mL protocol, demonstrating the clinical feasibility of lowering the risk of contrast-induced nephropathy through contrast volume reduction. (orig.)

  17. Intervertebral anticollision constraints improve out-of-plane translation accuracy of a single-plane fluoroscopy-to-CT registration method for measuring spinal motion

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Cheng-Chung; Tsai, Tsung-Yuan; Hsu, Shih-Jung [Institute of Biomedical Engineering, National Taiwan University, Taiwan 10051 (China); Lu, Tung-Wu [Institute of Biomedical Engineering, National Taiwan University, Taiwan 10051, Republic of China and Department of Orthopaedic Surgery, School of Medicine, National Taiwan University, Taiwan 10617 (China); Shih, Ting-Fang [Department of Medical Imaging, National Taiwan University, Taiwan 10051 (China); Wang, Ting-Ming [Department of Orthopaedic Surgery, National Taiwan University Hospital, Taiwan 10051 (China)

    2013-03-15

    Purpose: The study aimed to propose a new single-plane fluoroscopy-to-CT registration method integrated with intervertebral anticollision constraints for measuring three-dimensional (3D) intervertebral kinematics of the spine; and to evaluate the performance of the method without anticollision and with three variations of the anticollision constraints via an in vitro experiment. Methods: The proposed fluoroscopy-to-CT registration approach, called the weighted edge-matching with anticollision (WEMAC) method, was based on the integration of geometrical anticollision constraints for adjacent vertebrae and the weighted edge-matching score (WEMS) method that matched the digitally reconstructed radiographs of the CT models of the vertebrae and the measured single-plane fluoroscopy images. Three variations of the anticollision constraints, namely, T-DOF, R-DOF, and A-DOF methods, were proposed. An in vitro experiment using four porcine cervical spines in different postures was performed to evaluate the performance of the WEMS and the WEMAC methods. Results: The WEMS method gave high precision and small bias in all components for both vertebral pose and intervertebral pose measurements, except for relatively large errors for the out-of-plane translation component. The WEMAC method successfully reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five degrees of freedom (DOF) more or less unaltered. The means (standard deviations) of the out-of-plane translational errors were less than -0.5 (0.6) and -0.3 (0.8) mm for the T-DOF method and the R-DOF method, respectively. Conclusions: The proposed single-plane fluoroscopy-to-CT registration method reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five DOF more or less unaltered. With the submillimeter and subdegree accuracy, the WEMAC method was

  18. Diagnostic accuracy of contrast-enhanced MR angiography and unenhanced proton MR imaging compared with CT pulmonary angiography in chronic thromboembolic pulmonary hypertension.

    Science.gov (United States)

    Rajaram, Smitha; Swift, Andrew J; Capener, David; Telfer, Adam; Davies, Christine; Hill, Catherine; Condliffe, Robin; Elliot, Charles; Hurdman, Judith; Kiely, David G; Wild, Jim M

    2012-02-01

    To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE-MRA) and the added benefit of unenhanced proton MR angiography compared with CT pulmonary angiography (CTPA) in patients with chronic thromboembolic disease (CTE). A 2 year retrospective study of 53 patients with chronic thromboembolic pulmonary hypertension who underwent CTPA and MRI for suspected pulmonary hypertension and a control group of 36 patients with no CT evidence of pulmonary embolism. The MRI was evaluated for CTE and the combined diagnostic accuracy of ce-MRA and unenhanced proton MRA was determined. CE-MRA generated lung perfusion maps were also assessed. The overall sensitivity and specificity of CE-MRA in diagnosing proximal and distal CTE were 98% and 94%, respectively. The sensitivity improved from 50% to 88% for central vessel disease when CE-MRA images were analysed with unenhanced proton MRA. The CE-MRA identified more stenoses (29/18), post-stenosis dilatation (23/7) and occlusions (37/29) compared with CTPA. The CE-MRA perfusion images showed a sensitivity of 92% for diagnosing CTE. CE-MRA has high sensitivity and specificity for diagnosing CTE. The sensitivity of CE-MRA for visualisation of adherent central and lobar thrombus significantly improves with the addition of unenhanced proton MRA which delineates the vessel wall.

  19. Diagnostic accuracy of contrast-enhanced MR angiography and unenhanced proton MR imaging compared with CT pulmonary angiography in chronic thromboembolic pulmonary hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Rajaram, Smitha [Unit of Academic Radiology, University of Sheffield, Sheffield (United Kingdom); Academic Unit of Radiology, C Floor, Royal Hallamshire Hospital, Sheffield (United Kingdom); Swift, Andrew J.; Wild, Jim M. [Unit of Academic Radiology, University of Sheffield, Sheffield (United Kingdom); Sheffield Cardiovascular Biomedical Research Unit, Sheffield (United Kingdom); Capener, David; Telfer, Adam [Unit of Academic Radiology, University of Sheffield, Sheffield (United Kingdom); Davies, Christine; Hill, Catherine [Sheffield Teaching Hospitals Trust, Department of Radiology, Sheffield (United Kingdom); Condliffe, Robin; Elliot, Charles; Kiely, David G. [Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield (United Kingdom); Sheffield Cardiovascular Biomedical Research Unit, Sheffield (United Kingdom); Hurdman, Judith [Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield (United Kingdom)

    2012-02-15

    To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE-MRA) and the added benefit of unenhanced proton MR angiography compared with CT pulmonary angiography (CTPA) in patients with chronic thromboembolic disease (CTE). A 2 year retrospective study of 53 patients with chronic thromboembolic pulmonary hypertension who underwent CTPA and MRI for suspected pulmonary hypertension and a control group of 36 patients with no CT evidence of pulmonary embolism. The MRI was evaluated for CTE and the combined diagnostic accuracy of ce-MRA and unenhanced proton MRA was determined. CE-MRA generated lung perfusion maps were also assessed. The overall sensitivity and specificity of CE-MRA in diagnosing proximal and distal CTE were 98% and 94%, respectively. The sensitivity improved from 50% to 88% for central vessel disease when CE-MRA images were analysed with unenhanced proton MRA. The CE-MRA identified more stenoses (29/18), post-stenosis dilatation (23/7) and occlusions (37/29) compared with CTPA. The CE-MRA perfusion images showed a sensitivity of 92% for diagnosing CTE. CE-MRA has high sensitivity and specificity for diagnosing CTE. The sensitivity of CE-MRA for visualisation of adherent central and lobar thrombus significantly improves with the addition of unenhanced proton MRA which delineates the vessel wall. (orig.)

  20. Diagnostic accuracy and its affecting factors of dual-source CT for assessment of coronary stents patency and in-stent restenosis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing-hua; YANG Li; WU Jian; JU Hai-yue; ZHANG Fan; HE Bin; CHEN Yun-dai

    2012-01-01

    Background In-stent restenosis is a common complication after stent implantation.However,the assessment of stent lumen in computed tomography (CT) coronary angiography is limited by multiple factors.Our study aimed to evaluate the accuracy and the suspected affecting factors in diagnosing coronary in-stent restenosis by dual-source CT (DSCT) compared with coronary angiography.Methods One hundred and fifteen stents in 50 patients were evaluated with DSCT before coronary angiography for the detection of coronary in-stent restenosis (≥ 50% luminal narrowing).Patency of each stent was analyzed by two independent expert radiologists blinded to the results of coronary angiography.The relationship between diagnostic accuracy and the suspected factors including age,body mass index (BMI),heart rate,variation of heart rate,radiation dose,image quality,location and stent characteristics (type,material,diameter,length and strut thickness) was assessed wilh both univariate and multivariate analysis.The fitting of a Logistic regression model was evaluated using a receiver operating characteristic (ROC) curve.Results Mean stent diameter was (2.9±0.4) mm.Sensitivity,specificity,positive and negative predictive values and accuracy of DSCT in detection of in-stent restenosis were 69.2%,91.2%,50.0%,95.9%,and 88.7%,respectively.In a subgroup of stents with a diameter ≥3.0 mm,sensitivity,specificity,positive and negative predictive values and accuracy were 100.0%,96.5%,75.0%,100.0%+ and 96.8%,respectively.Stent diameter <3.0 mm and poor image quality were associated with poor diagnostic accuracy (P <0.05).The area under curve of ROC was 0.79.Conclusion DSCT can provide high accuracy for the assessment of in-stent restenosis in stents with a diameter ≥3.0mm,and can play an important role in ruling out in-stent restenosis.

  1. Prospective versus retrospective ECG gating for dual source CT of the coronary stent: Comparison of image quality, accuracy, and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Lei, E-mail: zhaolei219@sohu.com [Beijing Anzhen Hospital of the Capital University of Medical Sciences (China); Zhang Zhaoqi; Fan Zhanming; Yang Lin; Du Jing [Beijing Anzhen Hospital of the Capital University of Medical Sciences (China)

    2011-03-15

    Objective: To compare image quality, diagnostic accuracy and radiation dose of prospective and retrospective electrocardiogram (ECG) gated dual source computed tomography (DSCT) for the evaluation of the coronary stent, using conventional coronary angiography (CA) as a standard reference. Design, setting and patients: Sixty patients (heart rates {<=}70 bpm) with previous stent implantation who were scheduled for CA were divided in two groups, receiving either prospective or retrospective ECG gated DSCT separately. Two reviewers scored coronary stent image quality and evaluated stent lumen. Results: There was no significant difference in image quality between the two groups. In the prospective group, there were 86.4% (51/59) stents with interpretable images, in the retrospective group, there were 87.5% (49/56) stents with interpretable images. Image quality was not influenced by age, body mass index or heart rate in either group, but heart rate variability had a weak impact on the image quality of the prospective group. Image noise was higher in the prospective group, but this difference reached statistical significance only by using a smooth kernel reconstruction. Per-stent based sensitivity, specificity, and positive and negative predictive value were 100%, 84.1%, 68.2%, and 100%, respectively, in the prospective CT angiography group and 94.4%, 86.8%, 77.3%, and 97.1%, respectively, in the retrospective CT angiography group. There was a significant difference in the effective radiation dose between the two groups, mean effective dose in the prospective and retrospective group was 2.2 {+-} 0.5 mSv (1.5-3.2 mSv) and 14.6 {+-} 3.3 mSv (10.0-20.4 mSv) (p < .001) respectively. Conclusions: Compared with retrospective CT angiography, prospective CT angiography has a similar performance in assessing coronary stent patency, but a lower effective dose in selected patients with regular heart rates {<=}70 bpm.

  2. FDG-PET/CT characterization of adrenal nodules: diagnostic accuracy and interreader agreement using quantitative and qualitative methods.

    Science.gov (United States)

    Evans, Paul D; Miller, Chad M; Marin, Daniele; Stinnett, Sandra S; Wong, Terence Z; Paulson, Erik K; Ho, Lisa M

    2013-08-01

    To determine interreader agreement and diagnostic accuracy across varying levels of reader experience using qualitative and quantitative methods of evaluating adrenal nodules using ((18)F)-fluorodeoxyglucose-positron emission tomography/computed tomography. 132 adrenal nodules (96 adenomas, 36 metastases) were retrospectively identified in 105 patients (49 men and 56 women, mean age 66 years, age range 45-85 years) with a history of lung cancer who underwent ((18)F)-fluorodeoxyglucose-positron emission tomography/computed tomography. For each nodule, three readers independently performed one qualitative and two quantitative measurements: visual assessment, standardized uptake value (SUVmax), and standard uptake ratio (SUVratio). Interreader agreement was calculated using percent agreement with κ statistic for qualitative analysis and intraclass correlation coefficient (ICC) for quantitative analysis. Accuracy, sensitivity, and specificity for distinguishing benign from malignant adrenal nodules were calculated for each method. Percent agreement between readers for visual (qualitative) assessment was 92% to 96% and κ statistic was 0.79 to 0.90 (95% confidence limits 0.66-0.99). ICC for SUVmax was 92% to 99% (95% CL 0.8-1.0), and ICC for SUVratio was 89% to 99% (95% CL 0.74-0.99). For diagnosis of malignancy, mean sensitivity and specificity for visual assessment were 80% and 97%, respectively. Mean sensitivity and specificity for SUVmax were 91% and 81%, respectively; for SUVratio, 90% and 80%. Mean diagnostic accuracy was 93%, 83%, and 84% for visual assessment, SUVmax, and SUVratio, respectively. Excellent interreader agreement is seen for quantitative and qualitative methods of distinguishing benign from malignant adrenal nodules. Qualitative analysis demonstrated higher accuracy but lower sensitivity compared with quantitative analysis. Published by Elsevier Inc.

  3. Benefit of cerebrospinal fluid spectrophotometry in the assessment of CT scan negative suspected subarachnoid haemorrhage: a diagnostic accuracy study.

    Science.gov (United States)

    Hann, Angus; Chu, Kevin; Greenslade, Jaimi; Williams, Julian; Brown, Anthony

    2015-01-01

    This study aimed to determine if performing cerebrospinal fluid spectrophotometry in addition to visual inspection detects more ruptured cerebral aneurysms than performing cerebrospinal fluid visual inspection alone in patients with a normal head CT scan but suspected of suffering an aneurysmal subarachnoid haemorrhage (SAH). We performed a single-centre retrospective study of patients presenting to the emergency department of a tertiary hospital who underwent both head CT scan and lumbar puncture to exclude SAH. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of an approach utilising both spectrophotometry and visual inspection (combined approach) was compared to visual inspection alone. A total of 409 patients (mean age 37.8 years, 56.2% female) were recruited and six (1.5%) had a cerebral aneurysm on angiography. The sensitivity of visual inspection was 50% (95% confidence interval [CI]: 12.4-82.6%), specificity was 99% (95% CI: 97.5-99.7%), PPV was 42.9% (95% CI: 10.4-81.3%) and NPV was 99.2% (95% CI: 97.8-99.8%). The combined approach had a sensitivity of 100% (95% CI: 54.1-100%), specificity of 79.7% (95% CI: 75.4-83.5%), PPV of 6.8% (95% CI: 2.6-14.3%) and a NPV of 100% (95% CI: 98.8-100%). The sensitivity of the combined approach was not significantly different to that of visual inspection alone (p=0.25). Visual inspection had a significantly higher specificity than the combined approach (p<0.01). The combined approach detected more cases of aneurysmal SAH than visual inspection alone, however the difference in sensitivity was not statistically significant. Visual xanthochromia should prompt angiography because of a superior specificity and PPV. Due to its reduced sensitivity, caution should be applied when using only visual inspection of the supernatant.

  4. Diagnostic accuracy of three-dimensional contrast-enhanced MR angiography at 3-T for acute pulmonary embolism detection: comparison with multidetector CT angiography.

    Science.gov (United States)

    Zhang, Long Jiang; Luo, Song; Yeh, Benjamin M; Zhou, Chang Sheng; Tang, Chun Xiang; Zhao, Yan'e; Li, Lin; Zheng, Ling; Huang, Wei; Lu, Guang Ming

    2013-10-12

    Three-dimensional contrast-enhanced MR pulmonary angiography (MRPA) is a suitable option for pulmonary embolism (PE) detection. However, there have been few reports on the diagnostic accuracy of MRPA for PE detection in a 3-T MR system. The purpose of this study was to evaluate the accuracy of MRPA in a 3-T MR system to detect acute PE with multidetector CT pulmonary angiography (CTPA) as reference standard. Twenty-seven patients (18 males and 9 females, mean age 38.9±14.4 years) underwent both MRPA and CTPA within 3 days (range, 0-3 days) for evaluating PE. Pulmonary emboli in MRPA were independently analyzed on a per-patient and per-lobe basis by two radiologists. CTPA was regarded as reference standard, which was evaluated by another two radiologists in consensus. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for PE detection were calculated. Weighted κ values were calculated to evaluate agreement between readers. Twenty-four patients had PE in 55 lung lobes in CTPA, while 3 patients had no PE detected. Readers 1 and 2 correctly detected 47 and 46 lung lobes having clots in 24 and 23 patients, corresponding to sensitivities, specificities, PPV, NPV, and accuracies of 100%, 100%, 100%, 100%, 100%; 100%, 66.7%, 96.0%, 100%, 96.4% on a per-patient basis and 85.5%, 100%, 100%, 90.9%, 94.1%; 83.6%, 93.7%, 90.2%, 89.2%, 89.6% on a per-lobe basis; respectively. Excellent inter-reader agreement (κ values=1.00 and 0.934; both Pcontrast-enhanced MRPA with a 3-T MR system is a suitable alternative modality to CTPA to detect PE on a per-patient basis based on this small cohort study. © 2013.

  5. SU-E-T-189: First Experimental Verification of the Accuracy of Absolute Dose Reconstruction From PET-CT Imaging of Yttrium 90 Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Veltchev, I; Fourkal, E; Doss, M; Ma, C; Meyer, J; Yu, M; Horwitz, E [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-06-01

    Purpose: In the past few years there have been numerous proposals for 3D dose reconstruction from the PET-CT imaging of patients undergoing radioembolization treatment of the liver with yttrium-90 microspheres. One of the most promising techniques uses convolution of the measured PET activity distribution with a pre-calculated Monte Carlo dose deposition kernel. The goal of the present study is to experimentally verify the accuracy of this method and to analyze the significance of various error sources. Methods: Optically stimulated luminescence detectors (OSLD) were used (NanoDot, Landauer) in this experiment. Two detectors were mounted on the central axis of a cylinder filled with water solution of yttrium-90 chloride. The total initial activity was 90mCi. The cylinder was inserted in a larger water phantom and scanned on a Siemens Biograph 16 Truepoint PET-CT scanner. Scans were performed daily over a period of 20 days to build a calibration curve for the measured absolute activity spanning 7 yttrium-90 half-lives. The OSLDs were mounted in the phantom for a predetermined period of time in order to record 2Gy dose. The measured dose was then compared to the dose reconstructed from the activity density at the location of each dosimeter. Results: Thorough error analysis of the dose reconstruction algorithm takes into account the uncertainties in the absolute PET activity, branching ratios, and nonlinearity of the calibration curve. The measured dose for 105-minute exposure on day 10 of the experiment was 219(11)cGy, while the reconstructed dose at the location of the detector was 215(47)cGy. Conclusion: We present the first experimental verification of the accuracy of the convolution algorithm for absolute dose reconstruction of yttrium-90 microspheres. The excellent agreement between the measured and calculated point doses will encourage the broad clinical adoption of the convolution-based dose reconstruction algorithm, making future quantitative dose

  6. Diagnostic accuracy and tolerability of contrast enhanced CT colonoscopy in symptomatic patients with increased risk for colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ozsunar, Yelda [Department of Radiology, School of Medicine, Adnan Menderes University, Aydin (Turkey)], E-mail: yozsunar@adu.edu.tr; Coskun, Guelten [Izmir Ataturk Egitim ve Arastirma Hastanesi, Izmir (Turkey); Delibas, Naciye; Uz, Burcin [Department of Radiology, School of Medicine, Adnan Menderes University, Aydin (Turkey); Yuekselen, Vahit [Department of Gastroenterology, School of Medicine, Adnan Menderes University, Aydin (Turkey)

    2009-09-15

    Objective: We compared the accuracy and tolerability of intravenous contrast enhanced spiral computed tomography colonography (CTC) and optical colonoscopy (OC) for the detection of colorectal neoplasia in symptomatic patients for colorectal neoplasia. Methods: A prospective study was performed in 48 patients with symptomatic patients with increased risk for colorectal cancer. Spiral CTC was performed in supine and prone positions after colonic cleansing. The axial, 2D MPR and virtual endoluminal views were analyzed. Results of spiral CTC were compared with OC which was done within 15 days. The psychometric tolerance test was asked to be performed for both CTC and colonoscopy after the procedure. Results: Ten lesions in 9 of 48 patients were found in CTC and confirmed with OC. Two masses and eight polyps, consisted of 1 tubulovillous, 1 tubular, 2 villous adenoma, 4 adenomatous polyp, 4 adenocarcinoma, were identified. Lesion prevalence was 21%. Sensitivity, specificity, accuracy, positive and negative predictive values were found 100%, 87%, 89%, 67% and 100%, respectively. Psychometric tolerance test showed that CTC significantly more comfortable comparing with OC (p = 0.00). CTC was the preferred method in 37% while OC was preferred in 6% of patients. In both techniques, the most unpleasant part was bowel cleansing. Conclusion: Contrast enhanced CTC is a highly accurate method in detecting colorectal lesions. Since the technique was found to be more comfortable and less time consuming compare to OE, it may be preferable in management of symptomatic patients with increased risk for colorectal cancer.

  7. Accuracy of CT-guided joint aspiration in patients with suspected infection status post-total hip arthroplasty

    Energy Technology Data Exchange (ETDEWEB)

    Tomas, Xavier; Garcia-Diez, Ana Isabel; Pomes, Jaime [Universidad de Barcelona, Department of Radiology, Hospital Clinic, Barcelona (Spain); Bori, Guillem; Garcia, Sebastian; Gallart, Xavier; Martinez, Juan Carlos; Riba, Josep [Universidad de Barcelona, Department of Orthopaedics, Hospital Clinic, Barcelona (Spain); Soriano, Alex; Mensa, Josep [Universidad de Barcelona, Department of Infectious Diseases, Hospital Clinic, Barcelona (Spain); Rios, Jose [Statistical Unit de Suport a la Estadistica I Metodologia IDIBAPS, Barcelona (Spain); Almela, Manel [Universidad de Barcelona, Department of Microbiology, Hospital Clinic, Barcelona (Spain)

    2011-01-15

    To determine the accuracy of guided computed tomography aspiration in the detection of septic hip prosthesis before surgery. Sixty-three patients (35 women and 28 men; age range, 29-86 years; mean age, 71 years) with clinically suspected septic hip prosthesis were prospectively studied with independent review board (IRB) approval. Volume and microbiological cultures of aspirated fluid and several computed tomography imaging findings such as periprosthetic fluid collections, prosthetic acetabular malposition, and heterotopic ossification were analyzed. All patients underwent revision surgery and infection was finally diagnosed in 33 patients. Statistical comparative analysis was performed comparing computed tomography aspiration and surgical findings (95% CI; level of significance at P = 0.05 two-sided) with 70% sensitivity, 100% specificity, 84% accuracy, 100% positive predictive value, and 75% negative predictive value. Using Fisher's exact test, the presence of periprosthetic fluid collections (P = 0.001), prosthetic acetabular malposition (P = 0.025) and aspirated fluid volume (P = 0.009) were significantly higher in infected than in non-infected prostheses, whereas heterotopic ossification was not (P = 0.429). Computed tomography aspiration is accurate to preoperatively diagnose septic hip prosthesis on the basis of volume and bacterial cultures of aspirated joint fluid. Furthermore, imaging findings such as periprosthetic fluid collections and prosthetic acetabular malposition strongly suggest infected prosthesis. (orig.)

  8. Diagnostic accuracy of dual-source CT coronary angiography: The effect of average heart rate, heart rate variability, and calcium score in a clinical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Long-Jiang Zhang; Zhuo-Li Zhang; Chang-Sheng Zhou; Guang-Ming Lu (Dept. of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing Univ., Nanjing (China)), e-mail: cjr.luguangming@vip.163.com; Sheng-Yong Wu (Medical Imaging Inst. of Tianjin, Tianjin (China)); Jing Wang; Shi-Sen Jiang (Dept. of Cardiology, Jinling Hospital, Clinical School of Medical College, Nanjing Univ., Nanjing (China)); Ying Lu (Dept. of Radiology and Biomedical Imaging, Univ. of California, San Francisco, CA (United States))

    2010-09-15

    Background: Dual-source CT coronary angiography (CTCA) has been used to detect coronary artery disease; however, the factors with potential to affect its diagnostic accuracy remain to be defined. Purpose: To prospectively evaluate the accuracy of dual-source CTCA in diagnosing coronary artery stenosis according to conventional coronary angiography (CAG), and the effect of average heart rate, heart rate variability, and calcium score on the accuracy of CTCA. Material and Methods: A total of 113 patients underwent both dual-source CTCA and CAG. The results were used to evaluate the findings in dual-source CTCA to assess the accuracy in the diagnosis of =50% (significant stenosis) and >75% (severe stenosis) of coronary artery according to those by CAG. Patients were divided into subgroups according to their heart rate (HR), HR variability (HRV), and calcium score, and the accuracy of CTCA was further evaluated. The chi-square test was used to analyze the difference in sensitivity and specificity for the detection of =50% and >75% coronary stenosis among subgroups. The generalized estimation equation method was used in per-vessel analysis to adjust for within-patient correlation. Results: In all, 113 patients had 338 vessels and 1661 segments evaluated by CAG. Dual-source CTCA displayed 1527 segments (91.9%). Among them, 1468 segments (calcium score by CAG score 1, n=1018; score 2, n=270; score 3, n=180) were assessable in CTCA. On a per-patient analysis, the sensitivity and specificity of CTCA were 93.9% and 93.5% for significant stenosis and 86.9% and 98.1% for severe stenosis. On a per-vessel basis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. On a per-segment analysis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. Average HR had no effect on the sensitivity and specificity of CTCA (P>0.05); whereas HRV and calcium score had some effect on

  9. Determination of the optimal number of markers and individuals in a training population necessary for maximum prediction accuracy in F2 populations by using genomic selection models.

    Science.gov (United States)

    Peixoto, L A; Bhering, L L; Cruz, C D

    2016-11-21

    Genomic selection is a useful technique to assist breeders in selecting the best genotypes accurately. Phenotypic selection in the F2 generation presents with low accuracy as each genotype is represented by one individual; thus, genomic selection can increase selection accuracy at this stage of the breeding program. This study aimed to establish the optimal number of individuals required to compose the training population and to establish the amount of markers necessary to obtain the maximum accuracy by genomic selection methods in F2 populations. F2 populations with 1000 individuals were simulated, and six traits were simulated with different heritability values (5, 20, 40, 60, 80 and 99%). Ridge regression best linear unbiased prediction was used in all analyses. Genomic selection models were set by varying the number of individuals in the training population (2 to 1000 individuals) and markers (2 to 3060 markers). Phenotypic accuracy, genotypic accuracy, genetic variance, residual variance, and heritability were evaluated. Greater the number of individuals in the training population, higher was the accuracy; the values of genotypic and residual variances and heritability were close to the optimum value. Higher the heritability of the trait, higher is the number of markers necessary to obtain maximum accuracy, ranging from 200 for the trait with 5% heritability to 900 for the trait with 99% heritability. Therefore, genomic selection models for prediction in F2 populations must consist of 200 to 900 markers of major effect on the trait and more than 600 individuals in the training population.

  10. Solitary pulmonary nodule and 18F-FDG PET/CT. Part 2: accuracy, cost-effectiveness, and current recommendations*

    Science.gov (United States)

    Mosmann, Marcos Pretto; Borba, Marcelle Alves; de Macedo, Francisco Pires Negromonte; Liguori, Adriano de Araujo Lima; Villarim Neto, Arthur; de Lima, Kenio Costa

    2016-01-01

    A solitary pulmonary nodule is a common, often incidental, radiographic finding. The investigation and differential diagnosis of solitary pulmonary nodules remain complex, because there are overlaps between the characteristics of benign and malignant processes. There are currently many strategies for evaluating solitary pulmonary nodules. The main objective is to identify benign lesions, in order to avoid exposing patients to the risks of invasive methods, and to detect cases of lung cancer accurately, in order to avoid delaying potentially curative treatment. The focus of this study was to review the evaluation of solitary pulmonary nodules, to discuss the current role of 18F-fluorodeoxyglucose positron-emission tomography, addressing its accuracy and cost-effectiveness, and to detail the current recommendations for the examination in this scenario. PMID:27141133

  11. A priori estimation of accuracy and of the number of wells to be employed in limiting dilution assays

    Directory of Open Access Journals (Sweden)

    J.G. Chaui-Berlinck

    2000-08-01

    Full Text Available The use of limiting dilution assay (LDA for assessing the frequency of responders in a cell population is a method extensively used by immunologists. A series of studies addressing the statistical method of choice in an LDA have been published. However, none of these studies has addressed the point of how many wells should be employed in a given assay. The objective of this study was to demonstrate how a researcher can predict the number of wells that should be employed in order to obtain results with a given accuracy, and, therefore, to help in choosing a better experimental design to fulfill one's expectations. We present the rationale underlying the expected relative error computation based on simple binomial distributions. A series of simulated in machina experiments were performed to test the validity of the a priori computation of expected errors, thus confirming the predictions. The step-by-step procedure of the relative error estimation is given. We also discuss the constraints under which an LDA must be performed.

  12. Diagnostic accuracy and impact on management of {sup 18}F-FDG PET and PET/CT in colorectal liver metastasis: a meta-analysis and systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Maffione, Anna Margherita; Rubello, Domenico [S.M. della Misericordia Hospital, PET Unit, Nuclear Medicine Department, Rovigo (Italy); Lopci, Egesta [Humanitas Research Hospital, Department of Nuclear Medicine, Milano (Italy); Bluemel, Christina; Herrmann, Ken [University Hospital Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Giammarile, Francesco [Centre Hospitalier Lyon Sud Biophysique, Department of Nuclear Medicine, Lyon (France)

    2015-01-15

    The first aim of the review (aim 1) was to obtain the diagnostic performance values of {sup 18}F-FDG PET for the detection and staging of liver metastases in patients with colorectal cancer (CRC), the second aim (aim 2) was to compare PET and conventional imaging modalities, and the third aim (aim 3) was to evaluate the impact of PET on patient management. The incidence of extrahepatic disease (EHD) detected by PET is also reviewed. A comprehensive search was performed on PubMed/MEDLINE for studies evaluating PET and PET/CT in CRC patients with liver metastases up to June 2014. For inclusion PET had to have been performed prior to surgery, there had to be at least 18 patients in the study, and the reported data had to allow calculation of 2 x 2 contingency tables (for aim 1). A total of 18 studies were eligible for at least one of the three intended subanalyses including a total of 1,059 patients. Pooled sensitivity, specificity and accuracy and the corresponding 95 % confidence intervals were derived from the contingency tables on a patient basis (patient-based analysis, PBA) and a lesion basis (lesion-based analysis, LBA) for eight studies. Pooled sensitivity and specificity of PET on PBA were both 93 %. Corresponding values for LBA were 60 % and 79 %, respectively. Areas under the summary ROC were 0.97 for PBA and 0.67 for LBA. Regarding aim 2, PET had a slightly lower sensitivity than MRI and CT on PBA (93 %, 100 % and 98 %, respectively) and LBA (66 %, 89 % and 79 %, respectively) but appeared to be more specific than MRI and CT (86 %, 81 % and 67 %, respectively). PET findings resulted in changes in the management of a mean of 24 % of patients. The mean incidence of PET-based EHD was 32 %. This meta-analysis suggests that FDG PET/CT is highly accurate for the detection of liver metastases on a patient basis but less accurate on a lesion basis. Compared to MRI, PET is less sensitive but more specific and affects the management of about one-quarter of patients

  13. Explaining Air and Water Transport in Undisturbed Soils By X-Ray CT Derived Macroporosity and CT- Number-Derived Matrix Density

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per

    The characterization of soil pore space geometry is important to predict the fluxes of air, water and solutes through soil and understand soil hydrogeochemical functions. X-ray computed tomography (CT) -derived parameters were evaluated as predictors of water, air and solute transport through soil....... Forty five soil columns (20-cm × 20-cm) were collected at an agricultural field in Estrup, Denmark. The soil columns were scanned in a medical CT-scanner. Subsequent to this, non-reactive tracer leaching experiments were performed in the laboratory together with measurements of air permeability (Ka...... is considered a robust indicator of preferential flow. Meanwhile, CT-derived limiting macro-porosity was the best predictor for Ka and log10Ksat. A best subsets regression analysis was performed combining macroporosity, limiting macroporosity and CTmatrix. The predictions of water and air flow improved using...

  14. Coronary CT angiography using prospective ECG triggering. High diagnostic accuracy with low radiation dose; CT-Angiographie der Koronarien mit prospektivem EKG-Triggering. Hohe diagnostische Genauigkeit bei niedriger Strahlendosis

    Energy Technology Data Exchange (ETDEWEB)

    Arnoldi, E. [Medical University of South Carolina, Charleston, Department of Radiology and Radiological Science, Charleston (United States); Klinikum der Ludwigs-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Ramos-Duran, L.; Abro, J.A.; Costello, P. [Medical University of South Carolina, Charleston, Department of Radiology and Radiological Science, Charleston (United States); Zwerner, P.L.; Schoepf, U.J. [Medical University of South Carolina, Charleston, Department of Radiology and Radiological Science, Charleston (United States); Medical University of South Carolina, Charleston, Department of Medicine, Division of Cardiology, Charleston (United States); Nikolaou, K.; Reiser, M.F. [Klinikum der Ludwigs-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany)

    2010-06-15

    The purpose of this study was to evaluate the diagnostic performance of coronary CT angiography (coronary CTA) using prospective ECG triggering (PT) for the detection of significant coronary artery stenosis compared to invasive coronary angiography (ICA). A total of 20 patients underwent coronary CTA with PT using a 128-slice CT scanner (Definition trademark AS+, Siemens) and ICA. All coronary CTA studies were evaluated for significant coronary artery stenoses ({>=}50% luminal narrowing) by 2 observers in consensus using the AHA-15-segment model. Findings in CTA were compared to those in ICA. Coronary CTA using PT had 88% sensitivity in comparison to 100% with ICA, 95% to 88% specificity, 80% to 92% positive predictive value and 97% to 100% negative predictive value for diagnosing significant coronary artery stenosis on per segment per patient analysis, respectively. Mean effective radiation dose-equivalent of CTA was 2.6{+-}1 mSv. Coronary CTA using PT enables non-invasive diagnosis of significant coronary artery stenosis with high diagnostic accuracy in comparison to ICA and is associated with comparably low radiation exposure. (orig.) [German] Ziel unserer Untersuchungen war es, die CT-Angiographie der Koronarien (Koronar-CTA) unter Verwendung des prospektiven EKG-Triggerings (PT) hinsichtlich ihrer diagnostischen Genauigkeit zur Detektion signifikanter Koronarstenosen mit der Herzkatheteruntersuchung (HK) zu vergleichen. Bei 20 Patienten wurden eine Koronar-CTA mit PT an einem 128-Zeilen-CT-Scanner (Definition trademark, AS+, Siemens) und eine HK durchgefuehrt. Alle CTA-Studien wurden von 2 Radiologen bzgl. signifikanter Koronarstenosen ({>=}50% Lumeneinengung) anhand des 15-Segment-Modells der American Heart Association (AHA) im Konsensus ausgewertet. Die Ergebnisse der CTA wurden mit den Befunden der HK verglichen. Die Koronar-CTA mit PT zeigte fuer die Diagnose signifikanter Stenosen im Vergleich zur HK eine Sensitivitaet von 88 bzw. 100%, eine Spezifitaet

  15. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Liang Xin, E-mail: Xin.Liang@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); College of Stomatology, Dalian Medical University (China); Lambrichts, Ivo, E-mail: Ivo.Lambrichts@uhasselt.b [Department of Basic Medical Sciences, Histology and Electron Microscopy, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Sun Yi, E-mail: Sunyihello@hotmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Denis, Kathleen, E-mail: kathleen.denis@groept.b [Department of Industrial Sciences and Techology-Engineering (IWT), XIOS Hogeschool Limburg, Hasselt (Belgium); Hassan, Bassam, E-mail: b.hassan@acta.n [Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); Li Limin, E-mail: Limin.Li@uz.kuleuven.b [Department of Paediatric Dentistry and Special Dental Care, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Pauwels, Ruben, E-mail: Ruben.Pauwels@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Jacobs, Reinhilde, E-mail: Reinhilde.Jacobs@uz.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium)

    2010-08-15

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.

  16. Accuracy and feasibility of frameless stereotactic and robot-assisted CT-based puncture in interventional radiology. A comparative phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Stoffner, R.; Widmann, G.; Bale, R. [Radiologie, Medizinische Univ. Innsbruck (Austria); Augschoell, C. [Chirurgie, LKH Salzburg (Austria); Boehler, D. [LKH Salzburg (Austria)

    2009-09-15

    Purpose: To compare the accuracy of frameless stereotactic and robot-assisted puncture in vitro based on computed tomography (CT) imaging with a slice thickness of 1, 3, and 5 mm. Materials and Methods: 300 punctures were carried out with help of the Atlas aiming device guided by the optical navigation system Stealth Station TREONplus and 150 punctures were guided by the robotic assistance system Innomotion. Conically shaped rods were punctured with Kirschner wires. The accuracy was evaluated on the basis of control CTs by measuring the Euclidean distance between the wire tip and target and the normal distance between the target and wire. Results: With the Stealth Station a mean Euclidean distance of 1.94{+-}0.912, 2.2{+-}1.136, and 2.74{+-}1.166 mm at a slice thickness of 1, 3 and 5 mm, respectively, was reached. The mean normal distance was 1.64{+-}0.919, 1.84{+-}1.189, and 2.48{+-}1.196 mm, respectively. The Innomotion system resulted in a mean Euclidean distance of 1.69{+-}0.772, 1.91{+-}0.673, and 2.30{+-}0.881 mm, respectively, while the mean normal distance was (1.42{+-}0.78), 1.60{+-}0.733, and 1.98{+-}1.002 mm, respectively. A statistical significance between accuracies with both systems with 1 mm and 3 mm slices could not be detected (p > 0.05). At a slice thickness of 5 mm, the robot was significantly more accurate, but not as accurate as when using thinner slices (p < 0.05). The procedure time is longer for the Innomotion system ({proportional_to}30 vs. {proportional_to}18 min), and the practicability is higher with the Stealth Station. (orig.)

  17. Assessment of the accuracy of a Bayesian estimation algorithm for perfusion CT by using a digital phantom

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Makoto; Kudo, Kohsuke; Uwano, Ikuko; Goodwin, Jonathan; Higuchi, Satomi; Ito, Kenji; Yamashita, Fumio [Iwate Medical University, Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Yahaba (Japan); Boutelier, Timothe; Pautot, Fabrice [Olea Medical, Department of Research and Innovation, La Ciotat (France); Christensen, Soren [University of Melbourne, Department of Neurology and Radiology, Royal Melbourne Hospital, Victoria (Australia)

    2013-10-15

    A new deconvolution algorithm, the Bayesian estimation algorithm, was reported to improve the precision of parametric maps created using perfusion computed tomography. However, it remains unclear whether quantitative values generated by this method are more accurate than those generated using optimized deconvolution algorithms of other software packages. Hence, we compared the accuracy of the Bayesian and deconvolution algorithms by using a digital phantom. The digital phantom data, in which concentration-time curves reflecting various known values for cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and tracer delays were embedded, were analyzed using the Bayesian estimation algorithm as well as delay-insensitive singular value decomposition (SVD) algorithms of two software packages that were the best benchmarks in a previous cross-validation study. Correlation and agreement of quantitative values of these algorithms with true values were examined. CBF, CBV, and MTT values estimated by all the algorithms showed strong correlations with the true values (r = 0.91-0.92, 0.97-0.99, and 0.91-0.96, respectively). In addition, the values generated by the Bayesian estimation algorithm for all of these parameters showed good agreement with the true values [intraclass correlation coefficient (ICC) = 0.90, 0.99, and 0.96, respectively], while MTT values from the SVD algorithms were suboptimal (ICC = 0.81-0.82). Quantitative analysis using a digital phantom revealed that the Bayesian estimation algorithm yielded CBF, CBV, and MTT maps strongly correlated with the true values and MTT maps with better agreement than those produced by delay-insensitive SVD algorithms. (orig.)

  18. Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.

    Science.gov (United States)

    Marin, Daniele; Davis, Drew; Roy Choudhury, Kingshuk; Patel, Bhavik; Gupta, Rajan T; Mileto, Achille; Nelson, Rendon C

    2017-09-01

    Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for

  19. SU-E-J-190: Characterization of Radiation Induced CT Number Changes in Tumor and Normal Lung During Radiation Therapy for Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C; Liu, F; Tai, A; Gore, E; Johnstone, C; Li, X [Medical College of Wisconsin Milwaukee WI (United States)

    2014-06-01

    Purpose: To measure CT number (CTN) changes in tumor and normal lung as a function of radiation therapy (RT) dose during the course of RT delivery for lung cancer using daily IGRT CT images and single respiration phase CT images. Methods: 4D CT acquired during planning simulation and daily 3D CT acquired during daily IGRT for 10 lung cancer cases randomly selected in terms of age, caner type and stage, were analyzed using an in-house developed software tool. All patients were treated in 2 Gy fractions to primary tumors and involved nodal regions. Regions enclosed by a series of isodose surfaces in normal lung were delineated. The obtained contours along with target contours (GTVs) were populated to each singlephase planning CT and daily CT. CTN in term of Hounsfield Unit (HU) of each voxel in these delineated regions were collectively analyzed using histogram, mean, mode and linear correlation. Results: Respiration induced normal lung CTN change, as analyzed from single-phase planning CTs, ranged from 9 to 23 (±2) HU for the patients studied. Normal lung CTN change was as large as 50 (±12) HU over the entire treatment course, was dose and patient dependent and was measurable with dose changes as low as 1.5 Gy. For patients with obvious tumor volume regression, CTN within the GTV drops monotonically as much as 10 (±1) HU during the early fractions with a total dose of 20 Gy delivered. The GTV and CTN reductions are significantly correlated with correlation coefficient >0.95. Conclusion: Significant RT dose induced CTN changes in lung tissue and tumor region can be observed during even the early phase of RT delivery, and may potentially be used for early prediction of radiation response. Single respiration phase CT images have dramatically reduced statistical noise in ROIs, making daily dose response evaluation possible.

  20. SU-E-J-271: Correlation of CT Number Change with Radiation Treatment Response for Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dalah, E; Tai, A; Oshima, K; Hall, W; Knechtges, P; Erickson, B; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

    2015-06-15

    Purpose: It has been reported recently that radiation can induce CT number (CTN) change during radiation therapy (RT) delivery. In the effort to explore whether CTN can be used to assess RT response, we analyze the relationship between the pathological treatment response (PTR) and the changes of CTN, MRI, and PET before and after the neoadjuvant chemoradiation (nCR) for pancreatic adenocarcinoma. Methods: The preand post-nCR CT, MRI, and PET data for a total of 8 patients with resectable, or borderline resectable pancreatic head adenocarcinoma treated with nCR were retrospectively analyzed. Radiographic characteristics were correlated to PTR data. The histograms, means and standard derivations (SD) of the CTNs in pancreatic head (CTNPH), the GTV defined by ADC (CTNGTV), and the rest of pancreatic head (CTNPH-CTNGTV) were compared. Changes before and after nCR were correlated with the corresponding changes of ADC, lean body mass normalized SUV (SUVlb), and PTR using Pearson’ s correlation coefficient test. Results: The average mean and SD in CTPH for all the patients analyzed were higher in post-nCR (53.17 ± 31.05 HU) compared to those at pre-nCR (28.09 ± 4.253 HU). The CTNGTV were generally higher than CTNPH and CTNPH-CTNGTV, though the differences were not significant. The post-nCR changes of mean CTN, ADC, and SUVlb values in pancreatic head were correlated with PTR (R=0.3273/P=0.5357, R=−0.5455/P<0.0001, and R=0.7638/P=0.0357, respectively). The mean difference in the maximum tumor dimension measured from CTN, ADC, and SUVlb as compared with pathological measurements was −2.1, −0.5, and 0.22 cm, respectively. Conclusion: The radiation-induced change of CTN in pancreas head after chemoradiation therapy of pancreatic cancer was observed, which may be related to treatment responses as assessed by biological imaging and pathology. More data are needed to determine whether the CTN can be used as a quantitative biomarker for response to neoadjuvant therapy.

  1. Investigation on the 3 D geometric accuracy and on the image quality (MTF, SNR and NPS) of volume tomography units (CT, CBCT and DVT); Untersuchung zur geometrischen 3-D-Genauigkeit und zur Bildqualitaet (MTF, SRV und W) von Volumentomografie-Einrichtungen (CT, CBCT und DVT)

    Energy Technology Data Exchange (ETDEWEB)

    Blendl, C.; Selbach, M.; Uphoff, C. [Fachhochschule Koeln (Germany). Inst. fuer Medien- und Phototechnik; Fiebich, M.; Voigt, J.M. [Fachhochschule Giessen (DE). Inst. fuer Medizinische Physik und Strahlenschutz (IMPS)

    2012-01-15

    Purpose: The study aims at investigating how far image quality (MTF and NPS) differs in between CT, CBCT and DVT units and how far the geometrical 3 D accuracy and the HU calibration differ in respect to surgical or radio therapeutic planning. Materials and Methods: X ray image stacks have been made using a new designed test device which contains structures for measuring MTF, NPS, the 3 D accuracy and the Hounsfield calibration (jaw or skull program). The image stacks of the transversal images were analyzed with a dedicated computer program. Results: The MTF values are correlated with the physical resolution (CT and DVT) and are influenced by the used Kernel (CT). The NPS values are limited to an intra system comparison due to the insufficient HU accuracy. The 3 D accuracy is comparable in between the system types. Conclusions: The values of image quality are not yet correlated with dose values: NPS. Investigations to an appropriate dosimetry are ongoing to establish the ratio between dose and image quality (ALARA principle). No fundamental difference between the systems can be stated in respect radio therapeutic planning: improper HU calibration accuracy in CBCT and DVT units. The geometric 3 D accuracy of high performance DVT systems is greater than that of CT Systems. (orig.)

  2. Accuracy of a clinical PET/CT vs. a preclinical μPET system for monitoring treatment effects in tumour xenografts

    Energy Technology Data Exchange (ETDEWEB)

    Palmowski, Karin [Department of Experimental Molecular Imaging, RWTH-Aachen University, Aachen (Germany); Department of Pneumology and Critical Care Medicine, Thoraxklinik Heidelberg, University of Heidelberg, Heidelberg (Germany); Winz, Oliver [Department of Nuclear Medicine, RWTH-Aachen University, Aachen (Germany); Rix, Anne; Bzyl, Jessica [Department of Experimental Molecular Imaging, RWTH-Aachen University, Aachen (Germany); Behrendt, Florian F.; Verburg, Frederic A.; Mottaghy, Felix M. [Department of Nuclear Medicine, RWTH-Aachen University, Aachen (Germany); Palmowski, Moritz, E-mail: mpalmowski@ukaachen.de [Department of Experimental Molecular Imaging, RWTH-Aachen University, Aachen (Germany); Department of Nuclear Medicine, RWTH-Aachen University, Aachen (Germany); Academic Radiology Baden Baden, Diagnostic and Interventional Radiology, University Medical Center Heidelberg, Heidelberg (Germany)

    2013-08-15

    Purpose: Small animal imaging is of growing importance for preclinical research and drug development. Tumour xenografts implanted in mice can be visualized with a clinical PET/CT (cPET); however, it is unclear whether early treatment effects can be monitored. Thus, we investigated the accuracy of a cPET versus a preclinical μPET using {sup 18}F-FDG for assessing early treatment effects. Materials and methods: The spatial resolution and the quantitative accuracy of a clinical and preclinical PET were evaluated in phantom experiments. To investigate the sensitivity for assessing treatment response, A431 tumour xenografts were implanted in nude mice. Glucose metabolism was measured in untreated controls and in two therapy groups (either one or four days of antiangiogenic treatment). Data was validated by γ-counting of explanted tissues. Results: In phantom experiments, cPET enabled reliable separation of boreholes ≥ 5 mm whereas μPET visualized boreholes ≥ 2 mm. In animal studies, μPET provided significantly higher tumour-to-muscle ratios for untreated control tumours than cPET (3.41 ± 0.87 vs. 1.60 ± .0.28, respectively; p < 0.01). During treatment, cPET detected significant therapy effects at day 4 (p < 0.05) whereas μPET revealed highly significant therapy effects even at day one (p < 0.01). Correspondingly, γ-counting of explanted tumours indicated significant therapy effects at day one and highly significant treatment response at day 4. Correlation with γ-counting was good for cPET (r = 0.74; p < 0.01) and excellent for μPET (r = 0.85; p < 0.01). Conclusion: Clinical PET is suited to investigate tumour xenografts ≥ 5 mm at an advanced time-point of treatment. For imaging smaller tumours or for the sensitive assessment of very early therapy effects, μPET should be preferred.

  3. Accuracy of 18-F FDG PET/CT to detect bone marrow clearance in patients with peripheral T-cell lymphoma - tissue remains the issue.

    Science.gov (United States)

    Pham, Anthony Q; Broski, Stephen M; Habermann, Thomas M; Jevremovic, Dragan; Wiseman, Gregory A; Feldman, Andrew L; Maurer, Matthew J; Ristow, Kay M; Witzig, Thomas E

    2017-10-01

    Staging of peripheral T-cell non-Hodgkin lymphoma (PTCL) is determined by 18-F FDG PET scan and bone marrow biopsy. This study addressed the accuracy of PET at detecting bone marrow (BM) involvement at restaging in patients with known involvement pretreatment. We identified patients with biopsy proven BM PTCL at diagnosis and concomitant BM and PET at the end of therapy. Pre-treatment PET demonstrated 50% (8/16) had a false-negative PET scan of the BM. After induction, repeat biopsy revealed 62.5% (10/16) with BM involvement. Of these 10, two had a positive PET; eight were false negative by PET. Of the six patients with a negative posttherapy BM biopsy, four were PET negative and two false positive. The sensitivity of PET at end of treatment was 20% (2/10) with a specificity of 66.7% (4/6). PET/CT is not an accurate predictor of BM involvement in patients with known PTCL in the marrow.

  4. SU-E-J-46: Evaluation of the Accuracy of a Six Degree of Freedom Robotic Couch Using ConeBeam CT Images of the Isocal Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q; Driewer, J; Wang, S; Li, S; Zheng, D; Zhu, X; Zhen, W; Wahl, A; Lin, C; Thompson, R; Zhou, S; Enke, C [University of Nebraska Medical Center, Omaha, NE (United States)

    2015-06-15

    Purpose The accuracy of Varian PerfectPitch six degree of freedom (DOF) robotic couch was examined using Varian Isocal phantom and cone-beam CT (CBCT) system. Methods CBCT images of the Isocal phantom were taken at different pitch and roll angles. The pitch and roll angles were varied from 357 to 3 degrees in one degree increments by input from service console, generating a total of 49 combinations with couch angle (yaw) zero. The center positions of the 16 tungsten carbide BBs contained in the Isocal were determined with in-house image processing software. Expected BBs positions at different rotation angles were determined mathematically by applying a combined translation/rotation operator to BB positions at zero pitch and roll values. A least square method was used to minimize the difference between the expected BB positions and their measured positions. In this way rotation angles were obtained and compared with input values from the console. Results A total of 49 CBCT images with voxel sizes 0.51 mm × 0.51 mm × 1 mm were used in analysis. Among the 49 calculations, the maximum rotation angle differences were 0.1 degree, 0.15 degree, and 0.09 degree, for pitch, roll, and couch rotation, respectively. The mean ± standard-deviation angle differences were 0.028±0.001 degree, −0.043±0.003 degree, and −0.009±0.001 degree, for pitch, roll, and couch rotation, respectively. The maximum isocenter shifts were 0.3 mm, 0.5 mm, 0.4 mm in x, y, z direction respectively following IEC6127 convention. The mean isocenter shifts were 0.07±0.02 mm, −0.05±0.06 mm, and −0.12±0.02 mm in x, y and z directions. Conclusion The accuracy of the Varian PerfectPitch six DOF couch was studied with CBCTs of the Isocal phantom. The rotational errors were less than 0.15 degree and isocenter shifts were less than 0.5 mm in any direction. This accuracy is sufficient for stereotactic radiotherapy clinical applications.

  5. Determination of the integrated CT number of the whole liver in patients with severe hepatitis. As an indicator of the functional reserve of the liver

    Energy Technology Data Exchange (ETDEWEB)

    Kumahara, Tadashi; Muto, Yasutoshi; Moriwaki, Hisataka; Yoshida, Takashi; Tomita, Eiichi (Gifu Univ. (Japan). Faculty of Medicine)

    1989-06-01

    A study was conducted to estimate the functional reserve of the liver of patients with severe hepatitis by computed tomography (CT), in particular employing the integrated CT number of the whole liver (ICTN). ICTN was calculated by integrating the product of 'area' times 'mean CT number' of the liver in each CT slice for the entire height of the liver. The following results were obtained: (1) In patients with fulminant hepatitis (FH) as well as those with subacute hepatitis (SAH), ICTN was found to be significantly lower as compared to that of patients with acute hepatitis (AH) or non-hepatic diseases. In addition, in FH and SAH patients, ICTN showed a larger degree of decrease when compared with such conventional parameters as either estimated liver volume or mean hepatic CT number. Thus, ICTN seems to more sensitively reflect the changes in functional reserve of the liver. (2) ICTN showed significant positive correlations with prothrombin time and plasma BCAA/AAA ratio, and a significant negative correlation with plasma methionine level. (3) Time course of changes in ICTN correlated well with the clinical features of severe hepatitis. In particular, patients with initial ICTN values above 20 lcenter dotHU/m/sup 2/ of body surface area showed significantly higher survival rate than those with initial ICTN below 20. In conclusion, ICTN well indicates the functional reserve of the liver, and is further suggested to be valuable as a parameter to predict the prognosis of patients with severe hepatitis. (author).

  6. Accuracy of dual-source CT coronary angiography: first experience in a high pre-test probability population without heart rate control

    Energy Technology Data Exchange (ETDEWEB)

    Scheffel, Hans; Alkadhi, Hatem; Desbiolles, Lotus; Frauenfelder, Thomas; Schertler, Thomas; Husmann, Lars; Marincek, Borut; Leschka, Sebastian [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Plass, Andre; Vachenauer, Robert; Grunenfelder, Juerg; Genoni, Michele [Clinic for Cardiovascular Surgery, Zurich (Switzerland); Gaemperli, Oliver; Schepis, Tiziano [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); University of Zurich, Center for Integrative Human Physiology, Zurich (Switzerland)

    2006-12-15

    The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1{+-}11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14{+-}9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter {>=}1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3{+-}3.9 kg/m{sup 2} (range 22.4-36.3 kg/m{sup 2}), mean heart rate during CT was 70.3{+-}14.2 bpm (range 47-102 bpm), and mean Agatston score was 821{+-}904 (range 0-3,110). Image quality was diagnostic (scores 1-3) in 98.6% (414/420) of segments (mean image quality score 1.68{+-}0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control. (orig.)

  7. Accuracy of panoramic radiographs in determining the relationship of posterior root apices and maxillary sinus floor by Cone-Beam CT

    Directory of Open Access Journals (Sweden)

    Hoorieh Bashizadeh Fakhar

    2014-06-01

    Full Text Available   Background and Aims: It is crucial to verify the relationship between root apices and maxillary sinus floor in some surgical procedures like extraction and implant placement or in orthodontic movements like intrusion. Protrusion of roots into the sinus increases the risk of post extraction pneumatization which in turn decreases the available bone at the implant or denture sites. The aim of this study was to determine the panoramic radiology accuracy for defining the relationship between posterior root apices and the maxillary sinus floor by Cone Beam CT (CBCT.   Materials and Methods: Paired panoramic radiographs and CBCT images of 117 subjects were examined. 452 posterior maxillary roots including second premolar, first and second molar were classified by the means of the relationship with maxillary sinus floor. CBCT was used as Gold standard method, and the agreement of panoramic findings with CBCT was examined statistically. Data were analyzed using Chi-square and Multiple logistic regressions.   Results: Agreement of the panoramic and CBCT results were seen in 57.7% of all cases. Roots which had no contacts with the sinus floor (class 0 showed a high agreement of 89.5% between two imaging techniques. Roots in contact with sinus floor (class 1 showed 58.8 % and cases with root protrusion into sinus cavity (class 3, 4 showed 50% of agreement (P<0.001. Also in 36% of cases with no protrusion into the sinus cavity (class 0, 1, 2, panoramic showed protrusion. The agreement for the premolar was higher than molars (P<0.001   Conclusion: The majority of roots which their images were projected on the sinus cavity had no vertical protrusion in CBCT cuts. Considering the results, in these cases CBCT can be recommended.

  8. Accuracy of CT angiography in the assessment of the circle of Willis: comparison of volume-rendered images and digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Han, Ari; Yoon, Dae Young; Chang, Suk Ki (Dept. of Radiology, Kangdong Seong-Sim Hospital, Hallym Univ. College of Medicine, Seoul (Korea, Republic of)), email: evee0914@chollian.net; Lim, Kyoung Ja (Dept. of Radiology, Kangdong Seong-Sim Hospital, Hallym Univ. College of Medicine, Seoul (Korea, Republic of); Dept. of Radiology, Kangwon National Univ. College of Medicine, Chuncheon, Kangwon-do (Korea, Republic of)); Cho, Byung-Moon (Dept. of Neurosurgery, Kangdong Seong-Sim Hospital, Hallym Univ. College of Medicine, Seoul (Korea, Republic of)); Shin, Yoon Cheol (Dept. of Thoracic Surgery, Kangdong Seong-Sim Hospital, Hallym Univ. College of Medicine, Seoul (Korea, Republic of)); Kim, Sam Soo (Dept. of Radiology, Kangwon National Univ. College of Medicine, Chuncheon, Kangwon-do (Korea, Republic of)); Kim, Keon Ha (Dept. of Radiology, Samsung Medical Center, Sungkyunkwan Univ. College of Medicine, Seoul (Korea, Republic of))

    2011-10-15

    Background Computed tomography angiography (CTA) is increasingly used for non-invasive imaging of the cerebrovascular diseases. Purpose To evaluate the accuracy of CTA in the assessment of the variation of the segment calibers of the circle of Willis. Material and Methods One hundred and 17 patients with acute SAH (51 men and 66 women, mean age 50.9 years) who underwent CTA using a 16 detector-row CT scanner and DSA were evaluated retrospectively. The CTA and DSA studies were performed within 24 h after the onset of symptoms and within 24 h of each other. A total of 819 arterial segments (A-comA, right and left A1 segment, right and left P-com A, and right and left P1 segment) of the circle of Willis were determined to be aplastic (grade 1), hypoplastic (grade 2), or normal-sized (grade 3) by blinded observers evaluating CTA volume-rendered images. The CTA results were then compared with findings on the corresponding DSA images (reference standard). Results The overall agreement between CTA and DSA was 92.4%. We had 62 (7.6%) cases of disagreement (58 cases of under-estimation and four cases of over-estimation by CTA) between tow modalities. The sensitivity and specificity of CTA in the detection of aplastic and normal-sized segments were more than 90%. In contrast, subgroup analysis of the hypoplastic segments showed a sensitivity of 52.6% and a specificity of 98.2%. Conclusion CTA is highly accurate in the assessment of anatomical variations of the circle of Willis; however, its sensitivity is limited in depicting hypoplastic segments

  9. Estimating the Latent Number of Types in Growing Corpora with Reduced Cost-Accuracy Trade-Off

    Science.gov (United States)

    Hidaka, Shohei

    2016-01-01

    The number of unique words in children's speech is one of most basic statistics indicating their language development. We may, however, face difficulties when trying to accurately evaluate the number of unique words in a child's growing corpus over time with a limited sample size. This study proposes a novel technique to estimate the latent number…

  10. 对HT系统MVCT扫描图像CT值及噪声影响因素的研究%The research on the factors of effecting the CT number and noise of TomoTherapy MVCT

    Institute of Scientific and Technical Information of China (English)

    岳麒; 段继梅; 王志伟; 谷丹; 杨秀美; 李荣清

    2014-01-01

    Objective To study the CT number and noise of HT MVCT on different dose rate and scanning thickness.Methods The CT number of different relative electron density were measured in the MVCT image of Cheesephantom with tissue substitute plugs scanned with different dose rate and slice thickness.The physical density corresponding to the CT number was plotted as the image value to density table (IVDT).The noise was measured in the MVCT image of Cheesephantom with solid water plugs scanned with different dose rate and slice thickness.Results There was a significant different of the CT number of the plugs with different dose rates (P =0.000),it shows a positive correlation between the varied CT number and density (R2 =0.846),there is larger impact on the high density number.There was still a significant effect on the noise with different dose rate (P =0.000 density),the noise increase as the dose rate decrease.There was no significant effect on IVDT (P =1.000) and noise (P =0.667) with different slice thickness.Conclusions The CT number and the noise vary with the dose rate,the QA of MVCT should be performed regularly to assure the quality of image and the accuracy of dose calculating on MVCT in adaptive.%目的 探讨HT的MVCT扫描剂量率波动和不同扫描精度选择对图像CT值及噪声的影响.方法 MVCT在不同剂量率和扫描层厚下扫描带各种密度棒的水模体,对应各密度棒的CT值得出各自条件下的IVDT曲线进行对比.MVCT在不同剂量率和扫描层厚下扫描带有均匀密度棒的水模体,测量不同扫描条件下均匀水模体中的CT图像噪声.对结果进行方差及相关性分析.结果 不同扫描剂量率下对CT值影响显著(P=0.000),各密度棒对应CT值的变化大小与密度呈正相关(R2 =0.846),既高密度物质的CT值受的影响较大.不同剂量率对噪声也有显著影响,扫描剂量率越低图像噪声越大(P=0.000).2、4、6 mm扫描层厚对CT值(P=1.000)及图像噪声(P=0.667)

  11. Comparison of diagnostic accuracy of {sup 111}In-pentetreotide SPECT and {sup 68}Ga-DOTATOC PET/CT: A lesion-by-lesion analysis in patients with metastatic neuroendocrine tumours

    Energy Technology Data Exchange (ETDEWEB)

    Binnebeek, S. van; Vanbilloen, B.; Baete, K.; Terwinghe, C.; Koole, M.; Mortelmans, L. [KU Leuven, Nuclear Medicine, University Hospitals Leuven and Department of Imaging and Pathology, Leuven (Belgium); Mottaghy, F.M. [Maastricht University Medical Center, Department of Nuclear Medicine, Maastricht (Netherlands); University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Clement, P.M. [KU Leuven, Medical Oncology, University Hospitals Leuven and Laboratory of Experimental Oncology, Leuven (Belgium); Bogaerts, K. [KU Leuven and UHasselt, Department of Public Health and Primary Care (I-BioStat), Leuven (Belgium); Haustermans, K. [KU Leuven, Radiation Oncology, University Hospitals Leuven and Department of Oncology, Leuven (Belgium); Nackaerts, K. [University Hospitals Leuven, Pulmonology, Leuven (Belgium); Cutsem, E. van; Verslype, C. [KU Leuven, Division of Digestive Oncology, University Hospitals Leuven and Department of Oncology, Leuven (Belgium); Verbruggen, A. [KU Leuven, Laboratory for Radiopharmacy, Leuven (Belgium); Deroose, C.M. [KU Leuven, Nuclear Medicine, University Hospitals Leuven and Department of Imaging and Pathology, Leuven (Belgium); University Hospitals Leuven, Nuclear Medicine, Leuven (Belgium)

    2016-03-15

    To compare the diagnostic accuracy of {sup 111}In-pentetreotide-scintigraphy with {sup 68}Ga-DOTATOC-positron emission tomography (PET)/computed tomography (CT) in patients with metastatic-neuroendocrine tumour (NET) scheduled for peptide receptor radionuclide therapy (PRRT). Incremental lesions (ILs) were defined as lesions observed on only one modality. Fifty-three metastatic-NET-patients underwent {sup 111}In-pentetreotide-scintigraphy (24 h post-injection; planar+single-photon emission CT (SPECT) abdomen) and whole-body {sup 68}Ga-DOTATOC-PET/CT. SPECT and PET were compared in a lesion-by-lesion and organ-by-organ analysis, determining the total lesions and ILs for both modalities. Significantly more lesions were detected on {sup 68}Ga-DOTATOC-PET/CT versus {sup 111}In-pentetreotide-scintigraphy. More specifically, we observed 1,098 lesions on PET/CT (range: 1-105; median: 15) versus 660 on SPECT (range: 0-73, median: 9) (p<0.0001), with 439 PET-ILs (42/53 patients) and one SPECT-IL (1/53 patients). The sensitivity for PET/CT was 99.9 % (95 % CI, 99.3-100.0), for SPECT 60.0 % (95 % CI, 48.5-70.2). The organ-by-organ analysis showed that the PET-ILs were most frequently visualized in liver and skeleton. Ga-DOTATOC-PET/CT is superior for the detection of NET-metastases compared to {sup 111}In-pentetreotide SPECT. (orig.)

  12. Stable measures of number sense accuracy in math learning disability: Is it time to proceed from basic science to clinical application?

    Science.gov (United States)

    Júlio-Costa, Annelise; Starling-Alves, Isabella; Lopes-Silva, Júlia Beatriz; Wood, Guilherme; Haase, Vitor Geraldi

    2015-12-01

    Math learning disability (MLD) or developmental dyscalculia is a highly prevalent and persistent difficulty in learning arithmetic that may be explained by different cognitive mechanisms. The accuracy of the number sense has been implicated by some evidence as a core deficit in MLD. However, research on this topic has been mainly conducted in demographically selected samples, using arbitrary cut-off scores to characterize MLD. The clinical relevance of the association between number sense and MLD remains to be investigated. In this study, we aimed at assessing the stability of a number sense accuracy measure (w) across five experimental sessions, in two clinically defined cases of MLD. Stable measures of number sense accuracy estimate are required to clinically characterize subtypes of MLD and to make theoretical inferences regarding the underlying cognitive mechanisms. G. A. was a 10-year-old boy with MLD in the context of dyslexia and phonological processing impairment and his performance remained steadily in the typical scores range. The performance of H. V., a 9-year-old girl with MLD associated with number sense inaccuracy, remained consistently impaired across measurements, with a nonsignificant tendency to worsen. Qualitatively, H. V.'s performance was also characterized by greater variability across sessions. Concomitant clinical observations suggested that H. V.'s difficulties could be aggravated by developing symptoms of mathematics anxiety. Results in these two cases are in line with the hypotheses that at least two reliable patterns of cognitive impairment may underlie math learning difficulties in MLD, one related to number sense inaccuracy and the other to phonological processing impairment. Additionally, it indicates the need for more translational research in order to examine the usefulness and validity of theoretical advances in numerical cognition to the clinical neuropsychological practice with MLD.

  13. Accuracy of 16-slice multi-detector CT to quantify the degree of coronary artery stenosis: Assessment of cross-sectional and longitudinal vessel reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Cury, Ricardo C. [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States)]. E-mail: rcury@partners.org; Ferencik, Maros [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Achenbach, Stephan [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Division of Cardiology, Massachusetts General Hospital, Boston, MA (United States); Department of Internal Medicine II, University of Erlangen (Germany); Pomerantsev, Eugene [Division of Cardiology, Massachusetts General Hospital, Boston, MA (United States); Nieman, Koen [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Moselewski, Fabian [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Division of Cardiology, Massachusetts General Hospital, Boston, MA (United States); Abbara, Suhny [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Jang, Ik-Kyung [Division of Cardiology, Massachusetts General Hospital, Boston, MA (United States); Brady, Thomas J. [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Hoffmann, Udo [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States)

    2006-03-15

    Background: Sixteen-slice multi-detector computed tomography (MDCT) permits reliable noninvasive detection of significant coronary stenosis based on qualitative visual assessment. The purpose of this study was to determine the accuracy of MDCT to quantify the degree of coronary stenosis as compared to quantitative coronary angiography (QCA) using two different reconstruction methods. Methods: We studied 69 coronary artery lesions from 38 consecutive patients that underwent 16-slice MDCT as a part of research study, which enrolled consecutive subjects scheduled for clinically indicated invasive coronary angiography. Nine coronary artery lesions with motion artifacts, heavily calcified plaques or stents were excluded from the analysis. The degree of stenosis was calculated by two independent readers non-blinded to the location of the stenosis, but blinded to the results of the QCA. MDCT luminal diameters were measured in cross-sectional multi-planar reformatted (CS-MPR) images created perpendicular to the centerline of the vessel and in 5 mm thin-slab maximum intensity projections (MIP) parallel to the long axis of the vessel. Both MDCT methods were compared against QCA. Results: The mean degree of stenosis as measured by MDCT was closely correlated to QCA for both methods (CS-MPR versus QCA: 61 {+-} 23% versus 64 {+-} 29%; r {sup 2} = 0.83, p < 0.001 and MIP versus QCA: 64 {+-} 22% versus 64 {+-} 29%; r {sup 2} = 0.84, p < 0.001 for MIP. Bland-Altman analysis demonstrated a negative bias of the degree of stenosis of -2.8 {+-} 12% using CS-MPR and a minimally positive bias of 0.6 {+-} 12% for MIP. In stratified analysis for lesion severity (mild, 0-40%; moderate, 41-70% or severe, >70%) the agreement between both CS-MPR and MIP was high when compared to QCA ({kappa} = 0.74 and 0.71, respectively). Conclusion: Multi-detector spiral CT permits accurate quantitative assessment of the degree of coronary stenosis in selected data sets of sufficient quality using both

  14. Posttherapeutic {sup 131}I SPECT-CT offers high diagnostic accuracy when the findings on conventional planar imaging are inconclusive and allows a tailored patient treatment regimen

    Energy Technology Data Exchange (ETDEWEB)

    Kohlfuerst, S.; Igerc, I.; Gallowitsch, H.J.; Gomez-Segovia, I.; Matschnig, S.; Mayr, J.; Mikosch, P.; Lind, P. [State Hospital Klagenfurt, Department of Nuclear Medicine and Endocrinology, PET-CT Centre, Klagenfurt (Austria); Lobnig, M. [State Hospital Klagenfurt, Department of Radiology, Klagenfurt (Austria); Beheshti, M. [St. Vincent' s Hospital, Department of Nuclear Medicine and Endocrinology, Linz (Austria)

    2009-06-15

    The purpose of this prospective study was to determine the diagnostic impact and influence on patient treatment of posttherapeutic {sup 131}I SPECT-CT when the findings on planar posttherapeutic whole-body scintigraphy (ptWBS) were inconclusive. A total of 53 SPECT-CT scans were performed in 41 patients with thyroid cancer after high-dose {sup 131}I therapy (2.944 to 7.526 GBq {sup 131}I) because of diagnostic uncertainty on ptWBS. Physiological uptake in the salivary glands, gastric mucosa, gut, nasal mucosa, urinary tract and liver were considered to be normal. Any other foci of increased {sup 131}I uptake, except iodine uptake clearly located in the thyroid bed, were considered to be abnormal. The data were evaluated on a lesion and a patient basis. Regarding neck lesions, SPECT-CT provided a diagnostic impact in 26/90 lesions (28.9%) and confirmed the diagnosis in 64/90 lesions (71.1%). On a patient basis, SPECT-CT changed N status in 12/33 patients (36.4%), provided a diagnostic impact in 21/33 patients (63.6%) and led to a treatment change in 8/33 patients (24.2%). Regarding lesions distant from the neck, SPECT-CT confirmed the diagnosis in 62/71 lesions (87.3%) and had a diagnostic impact in 9/71 lesions (12.7%). On a patient basis, SPECT-CT changed M status in 4/19 patients (21.1%), had a diagnostic impact in 14/19 patients (73.7%) and led to a treatment change in 2/19 patients (10.5%). Considering all patients, SPECT-CT led to a treatment change in 10/41 patients (24.4%). Integrated SPECT-CT is a useful tool, especially in cases of diagnostic uncertainty and helps to individualize patient management. (orig.)

  15. Comparison of the diagnostic accuracy of CBCT and conventional CT in detecting degenerative osseous changes of the TMJ: A systematic review

    Directory of Open Access Journals (Sweden)

    Ranjeni Rajamani Veerappan

    2015-01-01

    Full Text Available Temporomandibular joint (TMJ disorders are a group of conditions that cause pain and dysfunction in the jaw joint and muscles that control jaw movement. According to the Research Diagnostic Criteria (RDC/TMD, temporomandibular disorders (TMDs may be classified into three different groups: a myofacial pain dysfunction syndrome (MPDS, b internal derangement, and c arthritis. Complicated anatomy of the TMJ was the reason for developing standardized radiographic techniques to diagnose TMDs. The introduction of computed tomography (CT in the diagnosis of TMJ disorders enabled much better delineation of anatomical structures of the joint due to lack of tissue superposition. Cone beam CT (CBCT is the latest imaging modality for craniofacial deformities, with a lesser radiation exposure and cheaper cost when compared to CT. A systematic literature search was done to identify articles describing degenerative osseous changes of the TMJ using CBCT and conventional CT. Electronic search of scientific papers was carried out in PubMed (MeSH, ScienceDirect, and Cochrane databases using specific keywords. In this systematic review, all the selected articles demonstrate the role of CBCT and CT in diagnosing the degenerative osseous changes of the TMJ. The studies included in the review suggested that CT has been the method of choice to assess the TMJ dynamics and contours of the cortical bone.

  16. SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Soultan, D [University of California-San Diego, San Diego State University, La Jolla, CA (United States); Murphy, J; James, C; Hoh, C; Moiseenko, V; Cervino, L [University of California, San Diego, La Jolla, CA (United States); Gill, B [British Columbia Cancer Agency, Windsor, ON (Canada)

    2015-06-15

    Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images were binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing.

  17. Increasing the accuracy of {sup 18}F-FDG PET/CT interpretation of “mildly positive” mediastinal nodes in the staging of non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Moloney, F., E-mail: fiachramoloney@hotmail.com [Department of Radiology, Cork University Hospital, Cork - 00353214922000 (Ireland); Ryan, D., E-mail: ryansurgeon@gmail.com [Department of Radiology, Cork University Hospital, Cork - 00353214922000 (Ireland); McCarthy, L., E-mail: lauraghmccarthy1@hotmail.com [Department of Radiology, Cork University Hospital, Cork - 00353214922000 (Ireland); McCarthy, J., E-mail: julie.mccarthy@hse.ie [Department of Pathology, Cork University Hospital, Cork - 0214922000 (Ireland); Burke, L., E-mail: louise.burke@hse.ie [Department of Pathology, Cork University Hospital, Cork - 0214922000 (Ireland); Henry, M.T., E-mail: michael.henry@hse.ie [Department of Respiratory Medicine, Cork University Hospital, Cork - 00353214922000 (Ireland); Kennedy, M.P., E-mail: marcus.kennedy@hse.ie [Department of Respiratory Medicine, Cork University Hospital, Cork - 00353214922000 (Ireland); Hinchion, J., E-mail: John.Hinchion@hse.ie [Department of Cardiothoracic Surgery, Cork University Hospital, Cork - 00353214922000 (Ireland); McSweeney, S., E-mail: Sean.McSweeny@hse.ie [Department of Radiology, Cork University Hospital, Cork - 00353214922000 (Ireland); Maher, M.M., E-mail: m.maher@ucc.ie [Department of Radiology, Cork University Hospital, Cork - 00353214922000 (Ireland); O’Regan, K., E-mail: kevin.ORegan1@hse.ie [Department of Radiology, Cork University Hospital, Cork - 00353214922000 (Ireland)

    2014-05-15

    Introduction: The aim of this study was to identify radiological factors that may reduce false-positive results and increase diagnostic accuracy when staging the mediastinum of patients with non-small cell lung carcinoma (NSCLC). Methods: This was a retrospective, interdisciplinary, per-node analysis study. We included patients with NSCLC and mediastinal nodes with an SUV max in the range of 2.5–4.0 on PET-CT. We hypothesized that the greatest number of false positive cases would occur in this cohort of patients. Results: A total of 92 mediastinal lymph nodes were analyzed in 44 patients. Mediastinal disease (N2/N3) was histologically confirmed in 15 of 44 patients and in 34 of 92 lymph nodes; positive predictive value of 37% and false positive rate of 63%. Lymph node SUV max, tumor size, ratio of node SUV max to tumor SUV max (SUVn/SUVp), and ratio of node SUV max to node size (SUV n/SADn) were significantly higher in true positive cases. Using a threshold of 0.3 for SUV node/tumor and 3 for SUV node/size yielded sensitivities of 91% and 71% and specificities of 71% and 69% respectively for the detection of mediastinal disease. Using both ratios in combination resulted in a sensitivity of 65% and a specificity of 88%. Concurrent benign lung disease was observed significantly more frequently in false-positive cases. Conclusion: SUVn/SUVpt and SUVn/SADn may be complimentary to conventional visual interpretation and SUV max measurement in the assessment of mediastinal disease in patients with NSCLC.

  18. An approach for quantitative image quality analysis for CT

    Science.gov (United States)

    Rahimi, Amir; Cochran, Joe; Mooney, Doug; Regensburger, Joe

    2016-03-01

    An objective and standardized approach to assess image quality of Compute Tomography (CT) systems is required in a wide variety of imaging processes to identify CT systems appropriate for a given application. We present an overview of the framework we have developed to help standardize and to objectively assess CT image quality for different models of CT scanners used for security applications. Within this framework, we have developed methods to quantitatively measure metrics that should correlate with feature identification, detection accuracy and precision, and image registration capabilities of CT machines and to identify strengths and weaknesses in different CT imaging technologies in transportation security. To that end we have designed, developed and constructed phantoms that allow for systematic and repeatable measurements of roughly 88 image quality metrics, representing modulation transfer function, noise equivalent quanta, noise power spectra, slice sensitivity profiles, streak artifacts, CT number uniformity, CT number consistency, object length accuracy, CT number path length consistency, and object registration. Furthermore, we have developed a sophisticated MATLAB based image analysis tool kit to analyze CT generated images of phantoms and report these metrics in a format that is standardized across the considered models of CT scanners, allowing for comparative image quality analysis within a CT model or between different CT models. In addition, we have developed a modified sparse principal component analysis (SPCA) method to generate a modified set of PCA components as compared to the standard principal component analysis (PCA) with sparse loadings in conjunction with Hotelling T2 statistical analysis method to compare, qualify, and detect faults in the tested systems.

  19. Estimation of CT cone-beam geometry using a novel method insensitive to phantom fabrication inaccuracy: Implications for isocenter localization accuracy

    Science.gov (United States)

    Chetley Ford, J.; Zheng, Dandan; Williamson, Jeffrey F.

    2011-01-01

    Purpose: Mechanical instabilities that occur during gantry rotation of on-board cone-beam computed tomography (CBCT) imaging systems limit the efficacy of image-guided radiotherapy. Various methods for calibrating the CBCT geometry and correcting errors have been proposed, including some that utilize dedicated fiducial phantoms. The purpose of this work was to investigate the role of phantom fabrication imprecision on the accuracy of a particular CT cone-beam geometry estimate and to test a new method to mitigate errors in beam geometry arising from imperfectly fabricated phantoms. Methods: The authors implemented a fiducial phantom-based beam geometry estimation following the one described by Cho et al. [Med Phys 32(4), 968–983 (2005)]. The algorithm utilizes as input projection images of the phantom at various gantry angles and provides a full nine parameter beam geometry characterization of the source and detector position and detector orientation versus gantry angle. A method was developed for recalculating the beam geometry in a coordinate system with origin at the source trajectory center and aligned with the axis of gantry rotation, thus making the beam geometry estimation independent of the placement of the phantom. A second CBCT scan with the phantom rotated 180° about its long axis was averaged with the first scan to mitigate errors from phantom imprecision. Computer simulations were performed to assess the effect of 2D fiducial marker positional error on the projections due to image discretization, as well as 3D fiducial marker position error due to phantom fabrication imprecision. Experimental CBCT images of a fiducial phantom were obtained and the algorithm used to measure beam geometry for a Varian Trilogy with an on-board CBCT. Results: Both simulations and experimental results reveal large sinusoidal oscillations in the calculated beam geometry parameters with gantry angle due to displacement of the phantom from CBCT isocenter and misalignment

  20. CT colonography with minimal bowel preparation: evaluation of tagging quality, patient acceptance and diagnostic accuracy in two iodine-based preparation schemes

    Energy Technology Data Exchange (ETDEWEB)

    Liedenbaum, Marjolein H. [Academic Medical Centre, Department of Radiology, Amsterdam (Netherlands); Academic Medical Center, Amsterdam (Netherlands); Vries, A.H. de; Bipat, S.; Stoker, J. [Academic Medical Centre, Department of Radiology, Amsterdam (Netherlands); Gouw, C.I.B.F. [Academic Medical Centre, Department of Radiology, Amsterdam (Netherlands); Gelre Hospitals, Department of Radiology, Apeldoorn (Netherlands); Rijn, A.F. van; Dekker, E. [Academic Medical Centre, Department of Gastroenterology and Hepatology, Amsterdam (Netherlands)

    2010-02-15

    The aim of this study was to compare a 1-day with a 2-day iodine bowel preparation for CT colonography in a positive faecal occult blood test (FOBT) screening population. One hundred consecutive patients underwent CT colonography and colonoscopy with segmental unblinding. The first 50 patients (group 1) ingested 7*50 ml iodinated contrast starting 2 days before CT colonography. The latter 50 patients (group 2) ingested 4*50 ml iodinated contrast starting 1 day before CT colonography. Per colonic segment measurements of residual stool attenuation and homogeneity were performed, and a subjective evaluation of tagging quality (grade 1-5) was done. Independently, two reviewers performed polyp and carcinoma detection. The tagging density was 638 and 618 HU (p = 0.458) and homogeneity 91 and 86 HU for groups 1 and 2, respectively (p = 0.145). The tagging quality was graded 5 (excellent) in 90% of all segments in group 1 and 91% in group 2 (p = 0.749). Mean per-polyp sensitivity for lesions {>=}10 mm was 86% in group 1 and 97% in group 2 (p = 0.355). Patient burden from diarrhoea significantly decreased for patients in group 2. One-day preparation with meglumine ioxithalamate results in an improved patient acceptability compared with 2-day preparation and has a comparable, excellent image quality and good diagnostic performance. (orig.)

  1. Accuracy and differential bias in copy number measurement of CCL3L1 in association studies with three auto-immune disorders

    Directory of Open Access Journals (Sweden)

    Carpenter Danielle

    2011-08-01

    Full Text Available Abstract Background Copy number variation (CNV contributes to the variation observed between individuals and can influence human disease progression, but the accurate measurement of individual copy numbers is technically challenging. In the work presented here we describe a modification to a previously described paralogue ratio test (PRT method for genotyping the CCL3L1/CCL4L1 copy variable region, which we use to ascertain CCL3L1/CCL4L1 copy number in 1581 European samples. As the products of CCL3L1 and CCL4L1 potentially play a role in autoimmunity we performed case control association studies with Crohn's disease, rheumatoid arthritis and psoriasis clinical cohorts. Results We evaluate the PRT methodology used, paying particular attention to accuracy and precision, and highlight the problems of differential bias in copy number measurements. Our PRT methods for measuring copy number were of sufficient precision to detect very slight but systematic differential bias between results from case and control DNA samples in one study. We find no evidence for an association between CCL3L1 copy number and Crohn's disease, rheumatoid arthritis or psoriasis. Conclusions Differential bias of this small magnitude, but applied systematically across large numbers of samples, would create a serious risk of false positive associations in copy number, if measured using methods of lower precision, or methods relying on single uncorroborated measurements. In this study the small differential bias detected by PRT in one sample set was resolved by a simple pre-treatment by restriction enzyme digestion.

  2. Initial implementation of the conversion from the energy-subtracted CT number to electron density in tissue inhomogeneity corrections: An anthropomorphic phantom study of radiotherapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Tsukihara, Masayoshi [Division of Radiological Technology, Graduate School of Health Sciences, Niigata University, Niigata 951-8518 (Japan); Noto, Yoshiyuki [Department of Radiology, Niigata University Medical and Dental Hospital, Niigata 951-8520 (Japan); Sasamoto, Ryuta; Hayakawa, Takahide; Saito, Masatoshi, E-mail: masaito@clg.niigata-u.ac.jp [Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Niigata University, Niigata 951-8518 (Japan)

    2015-03-15

    Purpose: To achieve accurate tissue inhomogeneity corrections in radiotherapy treatment planning, the authors had previously proposed a novel conversion of the energy-subtracted computed tomography (CT) number to an electron density (ΔHU–ρ{sub e} conversion), which provides a single linear relationship between ΔHU and ρ{sub e} over a wide range of ρ{sub e}. The purpose of this study is to present an initial implementation of the ΔHU–ρ{sub e} conversion method for a treatment planning system (TPS). In this paper, two example radiotherapy plans are used to evaluate the reliability of dose calculations in the ΔHU–ρ{sub e} conversion method. Methods: CT images were acquired using a clinical dual-source CT (DSCT) scanner operated in the dual-energy mode with two tube potential pairs and an additional tin (Sn) filter for the high-kV tube (80–140 kV/Sn and 100–140 kV/Sn). Single-energy CT using the same DSCT scanner was also performed at 120 kV to compare the ΔHU–ρ{sub e} conversion method with a conventional conversion from a CT number to ρ{sub e} (Hounsfield units, HU–ρ{sub e} conversion). Lookup tables for ρ{sub e} calibration were obtained from the CT image acquisitions for tissue substitutes in an electron density phantom (EDP). To investigate the beam-hardening effect on dosimetric uncertainties, two EDPs with different sizes (a body EDP and a head EDP) were used for the ρ{sub e} calibration. Each acquired lookup table was applied to two radiotherapy plans designed using the XiO TPS with the superposition algorithm for an anthropomorphic phantom. The first radiotherapy plan was for an oral cavity tumor and the second was for a lung tumor. Results: In both treatment plans, the performance of the ΔHU–ρ{sub e} conversion was superior to that of the conventional HU–ρ{sub e} conversion in terms of the reliability of dose calculations. Especially, for the oral tumor plan, which dealt with dentition and bony structures, treatment

  3. Increasing the accuracy of 18F-FDG PET/CT interpretation of "mildly positive" mediastinal nodes in the staging of non-small cell lung cancer.

    LENUS (Irish Health Repository)

    Moloney, F

    2014-05-01

    The aim of this study was to identify radiological factors that may reduce false-positive results and increase diagnostic accuracy when staging the mediastinum of patients with non-small cell lung carcinoma (NSCLC).

  4. Detection of walking periods and number of steps in older adults and patients with Parkinson's disease: accuracy of a pedometer and an accelerometry-based method.

    Science.gov (United States)

    Dijkstra, Baukje; Zijlstra, Wiebren; Scherder, Erik; Kamsma, Yvo

    2008-07-01

    The aim of this study was to examine if walking periods and number of steps can accurately be detected by a single small body-fixed device in older adults and patients with Parkinson's disease (PD). Results of an accelerometry-based method (DynaPort MicroMod) and a pedometer (Yamax Digi-Walker SW-200) worn on each hip were evaluated against video observation. Twenty older adults and 32 PD patients walked straight-line trajectories at different speeds, of different lengths and while doing secondary tasks in an indoor hallway. Accuracy of the instruments was expressed as absolute percentage error (older adults versus PD patients). Based on the video observation, a total of 236.8 min of gait duration and 24,713 steps were assessed. The DynaPort method predominantly overestimated gait duration (10.7 versus 11.1%) and underestimated the number of steps (7.4 versus 6.9%). Accuracy decreased significantly as walking distance decreased. Number of steps were also mainly underestimated by the pedometers, the left Yamax (6.8 versus 11.1%) being more accurate than the right Yamax (11.1 versus 16.3%). Step counting of both pedometers was significantly less accurate for short trajectories (3 or 5 m) and as walking pace decreased. It is concluded that the Yamax pedometer can be reliably used for this study population when walking at sufficiently high gait speeds (>1.0 m/s). The accelerometry-based method is less speed-dependent and proved to be more appropriate in the PD patients for walking trajectories of 5 m or more.

  5. The effect of sterilization and number of use on the accuracy of friction-style mechanical torque limiting devices for dental implants

    Directory of Open Access Journals (Sweden)

    Ali Fayaz

    2014-01-01

    Full Text Available Background: Mechanical torque limiting devices (MTLDs are necessary tools to control a peak torque and achieving target values of screw component of dental implants. Due to probable effect of autoclaving and number of use on the accuracy of these devices, this study aimed to evaluate the effect of sterilization and number of use on the accuracy of friction-style mechanical torque limiting devices (F-S MTLDs in achieving their target torque values. Materials and Methods: Peak torque measurements of 15 new F-S MTLDs from three different manufacturers (Astra Tech, BioHorizons, Dr. Idhe were measured ten times before and after 100 steam sterilization using a digital torque gauge. To simulate the clinical situation of aging (number of use target torque application process was repeated 10 times after each sterilization cycle and the peak torque values were registered. Comparison of the mean differences with target torque in each cycle was performed using one sample t test. Considering the type of MTLDs as inter subject comparison, One-way repeated measure ANOVA was used to evaluate the absolute values of differences between devices of each manufacturer in each group (α = 0.05. Results: The results of this study in Dr. Idhe group showed that, mean of difference values significantly differed from the target torque (P = 0.002 until 75 cycles. In Astra Tech group, also mean of difference values with under estimation trend, showed a significant difference with the target torque (P < 0.001. Mean of difference values significantly differed from the target torque with under estimation trend during all the 100 cycles in BioHorizons group (P < 0.05. Conclusion: The torque output of each individual device stayed in 10% difference from target torque values before 100 sterilization cycles, but more than 10% difference from the target torque was seen in varying degrees during these consequent cycles.

  6. The reconstruction algorithm used for [{sup 68}Ga]PSMA-HBED-CC PET/CT reconstruction significantly influences the number of detected lymph node metastases and coeliac ganglia

    Energy Technology Data Exchange (ETDEWEB)

    Krohn, Thomas [RWTH University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Ulm University, Department of Nuclear Medicine, Ulm (Germany); Birmes, Anita; Winz, Oliver H.; Drude, Natascha I. [RWTH University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Mottaghy, Felix M. [RWTH University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Maastricht UMC+, Department of Nuclear Medicine, Maastricht (Netherlands); Behrendt, Florian F. [RWTH University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Radiology Institute ' ' Aachen Land' ' , Wuerselen (Germany); Verburg, Frederik A. [RWTH University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); University Hospital Giessen and Marburg, Department of Nuclear Medicine, Marburg (Germany)

    2017-04-15

    To investigate whether the numbers of lymph node metastases and coeliac ganglia delineated on [{sup 68}Ga]PSMA-HBED-CC PET/CT scans differ among datasets generated using different reconstruction algorithms. Data were constructed using the BLOB-OS-TF, BLOB-OS and 3D-RAMLA algorithms. All reconstructions were assessed by two nuclear medicine physicians for the number of pelvic/paraaortal lymph node metastases as well the number of coeliac ganglia. Standardized uptake values (SUV) were also calculated in different regions. At least one [{sup 68}Ga]PSMA-HBED-CC PET/CT-positive pelvic or paraaortal lymph node metastasis was found in 49 and 35 patients using the BLOB-OS-TF algorithm, in 42 and 33 patients using the BLOB-OS algorithm, and in 41 and 31 patients using the 3D-RAMLA algorithm, respectively, and a positive ganglion was found in 92, 59 and 24 of 100 patients using the three algorithms, respectively. Quantitatively, the SUVmean and SUVmax were significantly higher with the BLOB-OS algorithm than with either the BLOB-OS-TF or the 3D-RAMLA algorithm in all measured regions (p < 0.001 for all comparisons). The differences between the SUVs with the BLOB-OS-TF- and 3D-RAMLA algorithms were not significant in the aorta (SUVmean, p = 0.93; SUVmax, p = 0.97) but were significant in all other regions (p < 0.001 in all cases). The SUVmean ganglion/gluteus ratio was significantly higher with the BLOB-OS-TF algorithm than with either the BLOB-OS or the 3D-RAMLA algorithm and was significantly higher with the BLOB-OS than with the 3D-RAMLA algorithm (p < 0.001 in all cases). The results of [{sup 68}Ga]PSMA-HBED-CC PET/CT are affected by the reconstruction algorithm used. The highest number of lesions and physiological structures will be visualized using a modern algorithm employing time-of-flight information. (orig.)

  7. Accuracy of dual-source CT to identify significant coronary artery disease in patients with uncontrolled hypertension presenting with chest pain: comparison with coronary angiography.

    Science.gov (United States)

    Marwan, Mohamed; Pflederer, Tobias; Schepis, Tiziano; Seltmann, Martin; Klinghammer, Lutz; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G; Achenbach, Stephan

    2012-06-01

    It has been previously reported that the sensitivity and specificity of multislice CT for detecting significant CAD (coronary artery disease) is high. Chest pain is a common presentation in patients with uncontrolled hypertension. We investigated the sensitivity and specificity of dual-source CT to detect and rule out significant CAD in patients presenting with uncontrolled hypertension accompanied by chest pain. 260 consecutive patients presenting with acute chest pain in the context of stage 2 hypertension (systolic pressure ≥160 and/or diastolic pressure ≥100) were enrolled in the study. After admission, control of blood pressure and risk stratification, 82 patients were excluded due to renal insufficiency, prior coronary revascularisation or refused participation in the study. 90 further patients with low pre-test probability of CAD were also excluded. 88 remaining patients were subjected to CT coronary angiography using dual-source CT (Definition, Siemens Medical Solutions, Forchheim, Germany) within 24 h before invasive coronary angiography. A contrast-enhanced volume dataset was acquired (120 kV, 400 mAs/rot, collimation 2 × 64 × 0.6 mm, retrospective ECG gating). Data sets were evaluated concerning the presence or absence of significant coronary stenoses and validated against invasive coronary angiography. A significant stenosis was assumed if the diameter reduction was ≥50%. 88 patients (mean age 66 ± 11 years, mean heart rate 61 ± 9 bpm) were evaluated regarding the presence or absence of significant CAD (at least one stenosis ≥50% diameter reduction). Mean systolic blood pressure on presentation was 203 ± 20 mmHg and mean diastolic blood pressure was 103 ± 13 mmHg. On a per patient basis, the sensitivity and specificity for dual-source CT to detect significant CAD in vessels >1.5 mm diameter was 100% (36/36, 95% CI 90-100) and 90% (47/52, 95% CI 79-97), respectively with a negative predictive value (NPV) of 100% (47/47, 95% CI 92-100) and a

  8. Image quality, radiation dose, and diagnostic accuracy of prospectively ECG-triggered high-pitch coronary CT angiography at 70 kVp in a clinical setting: comparison with invasive coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Long Jiang; Qi, Li; Zhou, Chang Sheng; Zhao, Yan E.; Li, Xie; Lu, Guang Ming [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Wang, Yining; Cao, Jian; Jin, Zhengyu [Peking Union Medical College Hospital, Department of Radiology, Beijing (China); Schoepf, U.J. [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Meinel, Felix G. [Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Ludwig-Maximilians-University Hospital, Institute for Clinical Radiology, Munich (Germany); Bayer, Richard R. [Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Gong, Jian Bin [Jinling Hospital, Medical School of Nanjing University, Department of Cardiology, Nanjing, Jiangsu (China)

    2016-03-15

    To investigate image quality, radiation dose, and diagnostic performance of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp compared to invasive coronary angiography (ICA) as reference standard. Forty-three patients underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp using 30 cc (11 g iodine) contrast medium and ICA. Subjective and objective image quality was evaluated for each CCTA study. CCTA performance for diagnosing ≥50 % stenosis was assessed. Results were stratified according to heart rate (HR), body mass index (BMI), Agatston score, and image quality. At CCTA, 94.3 % (500/530) of coronary segments were of diagnostic quality. Using ICA as reference standard, sensitivity and accuracy were 100 % and 93.0 % on a per-patient basis. Per-vessel and per-segment performances were 92.2 % and 89.5 %; 79.5 % and 88.3 %, respectively. No differences were found in diagnostic accuracy between different HR, BMI, and calcification subgroups (all P > 0.05) on a per-patient basis. However, low image quality reduced diagnostic accuracy on a per-patient, per-vessel and per-segment basis (all P < 0.05). The mean effective radiation dose was 0.2 ± 0.0 mSv. Our presented protocol results in an effective radiation dose of 0.2 mSv and high diagnostic accuracy for stenosis detection in a selected, non-obese population. (orig.)

  9. Assessment of the diagnostic accuracy of {sup 18}F-FDG PET/CT in prosthetic infective endocarditis and cardiac implantable electronic device infection: comparison of different interpretation criteria

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Ballve, Ana; Jesus Perez-Castejon, Maria; Carreras-Delgado, Jose L. [Clinico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, Department of Nuclear Medicine, Madrid (Spain); Delgado-Bolton, Roberto C. [Clinico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, Department of Nuclear Medicine, Madrid (Spain); San Pedro Hospital and Centre for Biomedical Research of La Rioja (CIBIR), University of La Rioja, Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, La Rioja (Spain); Sanchez-Enrique, Cristina; Vilacosta, Isidre; Vivas, David; Olmos, Carmen [Clinico San Carlos University Hospital, Department of Cardiology, Madrid (Spain); Ferrer, Manuel E.F. [Clinico San Carlos University Hospital, Research Unit, Madrid (Spain)

    2016-12-15

    The diagnosis of prosthetic valve (PV) infective endocarditis (IE) and infection of cardiac implantable electronic devices (CIEDs) remains challenging. The aim of this study was to assess the usefulness of {sup 18}F-FDG PET/CT in these patients and analyse the interpretation criteria. We included 41 patients suspected of having IE by the Duke criteria who underwent {sup 18}F-FDG PET/CT. The criteria applied for classifying the findings as positive/negative for IE were: (a) visual analysis of only PET images with attenuation-correction (AC PET images); (b) visual analysis of both AC PET images and PET images without AC (NAC PET images); (c) qualitative analysis of NAC PET images; and (d) semiquantitative analysis of AC PET images. {sup 18}F-FDG PET/CT was considered positive for IE independently of the intensity and distribution of FDG uptake. The gold standard was the Duke pathological criteria (if tissue was available) or the decision of an endocarditis expert team after a minimum 4 months follow-up. We studied 62 areas with suspicion of IE, 28 areas (45 %) showing definite IE and 34 (55 %) showing possible IE. Visual analysis of only AC PET images showed poor diagnostic accuracy (sensitivity 20 %, specificity 57 %). Visual analysis of both AC PET and NAC PET images showed excellent sensitivity (100 %) and intermediate specificity (73 %), focal uptake being more frequently associated with IE. The accuracy of qualitative analysis of NAC PET images depended on the threshold: the maximum sensitivity, specificity and accuracy achieved were 88 %, 80 %, 84 %, respectively. In the semiquantitative analysis of AC PET images, SUVmax was higher in areas of confirmed IE than in those without IE (∇SUVmax 2.2, p < 0.001). When FDG uptake was twice that in the liver, IE was always confirmed, and SUVmax 5.5 was the optimal threshold for IE diagnosis using ROC curve analysis (area under the curve 0.71). The value of {sup 18}F-FDG PET/CT in the diagnosis of suspected IE of PVs

  10. Effects of the number of markers per haplotype and clustering of haplotypes on the accuracy of QTL mapping and prediction of genomic breeding values

    Directory of Open Access Journals (Sweden)

    Schrooten Chris

    2009-01-01

    Full Text Available Abstract The aim of this paper was to compare the effect of haplotype definition on the precision of QTL-mapping and on the accuracy of predicted genomic breeding values. In a multiple QTL model using identity-by-descent (IBD probabilities between haplotypes, various haplotype definitions were tested i.e. including 2, 6, 12 or 20 marker alleles and clustering base haplotypes related with an IBD probability of > 0.55, 0.75 or 0.95. Simulated data contained 1100 animals with known genotypes and phenotypes and 1000 animals with known genotypes and unknown phenotypes. Genomes comprising 3 Morgan were simulated and contained 74 polymorphic QTL and 383 polymorphic SNP markers with an average r2 value of 0.14 between adjacent markers. The total number of haplotypes decreased up to 50% when the window size was increased from two to 20 markers and decreased by at least 50% when haplotypes related with an IBD probability of > 0.55 instead of > 0.95 were clustered. An intermediate window size led to more precise QTL mapping. Window size and clustering had a limited effect on the accuracy of predicted total breeding values, ranging from 0.79 to 0.81. Our conclusion is that different optimal window sizes should be used in QTL-mapping versus genome-wide breeding value prediction.

  11. Effects of the number of markers per haplotype and clustering of haplotypes on the accuracy of QTL mapping and prediction of genomic breeding values.

    Science.gov (United States)

    Calus, Mario P L; Meuwissen, Theo H E; Windig, Jack J; Knol, Egbert F; Schrooten, Chris; Vereijken, Addie L J; Veerkamp, Roel F

    2009-01-15

    The aim of this paper was to compare the effect of haplotype definition on the precision of QTL-mapping and on the accuracy of predicted genomic breeding values. In a multiple QTL model using identity-by-descent (IBD) probabilities between haplotypes, various haplotype definitions were tested i.e. including 2, 6, 12 or 20 marker alleles and clustering base haplotypes related with an IBD probability of > 0.55, 0.75 or 0.95. Simulated data contained 1100 animals with known genotypes and phenotypes and 1000 animals with known genotypes and unknown phenotypes. Genomes comprising 3 Morgan were simulated and contained 74 polymorphic QTL and 383 polymorphic SNP markers with an average r2 value of 0.14 between adjacent markers. The total number of haplotypes decreased up to 50% when the window size was increased from two to 20 markers and decreased by at least 50% when haplotypes related with an IBD probability of > 0.55 instead of > 0.95 were clustered. An intermediate window size led to more precise QTL mapping. Window size and clustering had a limited effect on the accuracy of predicted total breeding values, ranging from 0.79 to 0.81. Our conclusion is that different optimal window sizes should be used in QTL-mapping versus genome-wide breeding value prediction.

  12. A critical analysis of the combined usage of protein localization prediction methods: Increasing the number of independent data sets can reduce the accuracy of predicted mitochondrial localization

    Science.gov (United States)

    Lythgow, Kieren T.; Hudson, Gavin; Andras, Peter; Chinnery, Patrick F.

    2011-01-01

    In the absence of a comprehensive experimentally derived mitochondrial proteome, several bioinformatic approaches have been developed to aid the identification of novel mitochondrial disease genes within mapped nuclear genetic loci. Often, many classifiers are combined to increase the sensitivity and specificity of the predictions. Here we show that the greatest sensitivity and specificity are obtained by using a combination of seven carefully selected classifiers. We also show that increasing the number of independent prediction methods can paradoxically decrease the accuracy of predicting mitochondrial localization. This approach will help to accelerate the identification of new mitochondrial disease genes by providing a principled way for the selection for combination of appropriate prediction methods of mitochondrial localization of proteins. PMID:21195798

  13. Diagnostic accuracy and utility of coronary CT angiography with consideration of unevaluable results: A systematic review and multivariate Bayesian random-effects meta-analysis with intention to diagnose

    Energy Technology Data Exchange (ETDEWEB)

    Menke, Jan [University Medical Center Goettingen, Institute for Diagnostic and Interventional Radiology, Goettingen (Germany); Kowalski, Joerg [Dr. Lauterbach-Klinik, Department of Cardiology, Bad Liebenstein (Germany)

    2016-02-15

    To meta-analyze diagnostic accuracy, test yield and utility of coronary computed tomography angiography (CCTA) in coronary artery disease (CAD) by an intention-to-diagnose approach with inclusion of unevaluable results. Four databases were searched from 1/2005 to 3/2013 for prospective studies that used 16-320-row or dual-source CTs and provided 3 x 2 patient-level data of CCTA (positive, negative, or unevaluable) versus catheter angiography (positive or negative) for diagnosing ≥50 % coronary stenoses. A Bayesian multivariate 3 x 2 random-effects meta-analysis considered unevaluable CCTAs. Thirty studies (3422 patients) were included. Compared to 16-40 row CT, test yield and accuracy of CCTA has significantly increased with ≥64-row CT (P < 0.05). In ≥64-row CT, about 2.5 % (95 %-CI, 0.9-4.8 %) of diseased patients and 7.5 % (4.5-11.2 %) of non-diseased patients had unevaluable CCTAs. A positive likelihood ratio of 8.9 (6.1-13.5) indicated moderate suitability for identifying CAD. A negative likelihood ratio of 0.022 (0.01-0.04) indicated excellent suitability for excluding CAD. Unevaluable CCTAs had an equivocal likelihood ratio of 0.42 (0.22-0.71). In the utility analysis, CCTA was useful at intermediate pre-test probabilities (16-70 %). CCTA is useful at intermediate CAD pre-test probabilities. Positive CCTAs require verification to confirm CAD, unevaluable CCTAs require alternative diagnostics, and negative CCTAs exclude obstructive CAD with high certainty. (orig.)

  14. Analyzing indirect effects in cluster randomized trials. The effect of estimation method, number of groups and group sizes on accuracy and power.

    Directory of Open Access Journals (Sweden)

    Joop eHox

    2014-02-01

    Full Text Available Cluster randomized trials assess the effect of an intervention that is carried out at the group or cluster level. Ajzen’s theory of planned behaviour is often used to model the effect of the intervention as an indirect effect mediated in turn by attitude, norms and behavioural intention. Structural equation modelling (SEM is the technique of choice to estimate indirect effects and their significance. However, this is a large sample technique, and its application in a cluster randomized trial assumes a relatively large number of clusters. In practice, the number of clusters in these studies tends to be relatively small, e.g. much less than fifty. This study uses simulation methods to find the lowest number of clusters needed when multilevel SEM is used to estimate the indirect effect. Maximum likelihood estimation is compared to Bayesian analysis, with the central quality criteria being accuracy of the point estimate and the confidence interval. We also investigate the power of the test for the indirect effect. We conclude that Bayes estimation works well with much smaller cluster level sample sizes such as 20 cases than maximum likelihood estimation; although the bias is larger the coverage is much better. When only 5 to 10 clusters are available per treatment condition even with Bayesian estimation problems occur.

  15. 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.

    Science.gov (United States)

    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 Crohn disease, despite an inferior subjective image quality. (©) RSNA, 2016 Online

  16. Stroke risk after abrupt internal carotid artery sacrifice: Accuracy of preoperative assessment with balloon test occlusion and stable xenon-enhanced CT

    Energy Technology Data Exchange (ETDEWEB)

    Linskey, M.E.; Jungreis, C.A.; Yonas, H.; Hirsch, W.L. Jr.; Sekhar, L.N.; Horton, J.A.; Janosky, J.E. [Univ. of Pittsburgh School of Medicine, PA (United States)

    1994-05-01

    To evaluate stable xenon-enhanced CT cerebral blood flow with balloon test occlusion as a predictor of stroke risk in internal carotid artery sacrifice. Abrupt internal carotid artery occlusion was performed by surgical or endovascular means below the origin of the ophthalmic artery in 31 normotensive patients who were assessed preoperatively by a 15-minute clinical balloon test occlusion followed by an internal carotid artery-occluded xenon CT cerebral blood flow study. One patient, who passed the clinical test occlusion but exhibited regions of cerebral blood flow less than 30 mL/100 g per minute on the occlusion xenon CT cerebral blood flow study went on to have a fatal stroke corresponding exactly to the region of assessment. Neuroimaging demonstrated possible flow-related infarctions, which subsequently developed in three patients. Two patients were asymptomatic, and one patient was left with a mild residual hemiparesis. Our protocol provided a statistically significant reduction in subsequent infarction rate and infarction-related death rate when compared with a control group of normotensive abrupt internal carotid artery occlusion patients who did not undergo any preoperative stroke-risk assessment (reported in the literature). The estimated false-negative rate for our preoperative assessment protocol ranged from 3.3% to 10% depending on the assessment of the cause of the three potentially flow-related infarctions. Although life-threatening major vascular territory infarctions have been avoided, our protocol is less sensitive to changes predicting smaller, often minimally symptomatic, vascular border zone infarctions and does not predict postoperative thromboembolic strokes. 94 refs., 5 figs., 4 tabs.

  17. SPECT/CT in pediatric patient management

    Energy Technology Data Exchange (ETDEWEB)

    Nadel, Helen R. [British Columbia Children' s Hospital, University of British Columbia, Pediatric Radiologist and Nuclear Medicine Physician, Division of Nuclear Medicine Department of Radiology, Vancouver, British Columbia (Canada)

    2014-05-15

    Hybrid SPECT/CT imaging is becoming the standard of care in pediatric imaging. Indications are mainly for oncologic imaging including mIBG scintigraphy for neuroblastoma and I-123 post surgical imaging of children with thyroid carcinoma, bone scintigraphy for back pain, children referred from sports medicine and neurodevelopmentally delayed children presenting with pain symptoms. The studies provide improved diagnostic accuracy, and oncologic imaging that includes optimized CT as part of the SPECT/CT study may decrease the number of studies and sedation procedures an individual child may need. The studies, however, must be tailored on an individual basis as the addition of the CT study can increase exposure to the child and should only be performed after appropriate justification and with adherence to optimized low dose pediatric protocols. (orig.)

  18. Accuracy and the influence of marrow fat on quantitative CT and dual-energy X-ray absorptiometry measurements of the femoral neck in vitro

    NARCIS (Netherlands)

    J.W. Kuiper; C. van Kuijk (Cornelis); J.L. Grashuis (Jan); A.G.H. Ederveen (Antwan); H.E. Schütte (Henri)

    1996-01-01

    markdownabstractAbstract Bone mineral measurements with quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA) were compared with chemical analysis (ChA) to determine (1) the accuracy and (2) the influence of bone marrow fat. Total bone mass of 19 human femoral necks in

  19. Diagnostic accuracy of 16-slice multidetector-row CT for detection of in-stent restenosis vs detection of stenosis in nonstented coronary arteries.

    Science.gov (United States)

    Kefer, Joelle M; Coche, Emmanuel; Vanoverschelde, Jean-Louis J; Gerber, Bernhard L

    2007-01-01

    The purpose of this study was to assess the diagnostic accuracy of 16-slice multidetector-row computed tomography (MDCT) for detecting in-stent restenosis. Fifty patients with 69 previously implanted coronary stents underwent 16-slice MDCT before quantitative coronary angiography (QCA). Diagnostic accuracy of MDCT for detection of in-stent restenosis defined as >50% lumen diameter stenosis (DS) in stented and nonstented coronary segments >1.5-mm diameter was computed using QCA as reference. According to QCA, 18/69 (25%) stented segments had restenosis. In addition, 33/518 (6.4%) nonstented segments had >50% DS. In-stent restenosis was correctly identified on MDCT images in 12/18 stents, and absence of restenosis was correctly identified in 50/51 stents. Stenosis in native coronary arteries was correctly identified in 22/33 segments and correctly excluded in 482/485 segments. Thus, sensitivity (67% vs 67% p=1.0), specificity (98% vs 99%, p=0.96) and overall diagnostic accuracy (90% vs 97%, p=0.68) was similarly high for detecting in-stent restenosis as for detecting stenosis in nonstented coronary segments. MDCT has similarly high diagnostic accuracy for detecting in-stent restenosis as for detecting coronary artery disease in nonstented segments. This suggests that MDCT could be clinically useful for identification of restenosis in patients after coronary stenting.

  20. Diagnostic accuracy of 16-slice multidetector-row CT for detection of in-stent restenosis vs detection of stenosis in nonstented coronary arteries

    Energy Technology Data Exchange (ETDEWEB)

    Kefer, Joelle M.; Vanoverschelde, Jean-Louis J.; Gerber, Bernhard L. [Cliniques Universitaires St. Luc UCL, Department of Cardiology, Brussels (Belgium); Coche, Emmanuel [Cliniques Universitaires St. Luc UCL, Department of Radiology, Brussels (Belgium)

    2007-01-15

    The purpose of this study was to assess the diagnostic accuracy of 16-slice multidetector-row computed tomography (MDCT) for detecting in-stent restenosis. Fifty patients with 69 previously implanted coronary stents underwent 16-slice MDCT before quantitative coronary angiography (QCA). Diagnostic accuracy of MDCT for detection of in-stent restenosis defined as >50% lumen diameter stenosis (DS) in stented and nonstented coronary segments >1.5-mm diameter was computed using QCA as reference. According to QCA, 18/69 (25%) stented segments had restenosis. In addition, 33/518 (6.4%) nonstented segments had >50% DS. In-stent restenosis was correctly identified on MDCT images in 12/18 stents, and absence of restenosis was correctly identified in 50/51 stents. Stenosis in native coronary arteries was correctly identified in 22/33 segments and correctly excluded in 482/485 segments. Thus, sensitivity (67% vs 67% p=1.0), specificity (98% vs 99%, p=0.96) and overall diagnostic accuracy (90% vs 97%, p=0.68) was similarly high for detecting in-stent restenosis as for detecting stenosis in nonstented coronary segments. MDCT has similarly high diagnostic accuracy for detecting in-stent restenosis as for detecting coronary artery disease in nonstented segments. This suggests that MDCT could be clinically useful for identification of restenosis in patients after coronary stenting. (orig.)

  1. Indication for and accuracy of CT and MRI of the temporomandibular joint; Indikation und Aussagekraft von Computertomographie und Magnetresonanztomographie des Kiefergelenks

    Energy Technology Data Exchange (ETDEWEB)

    Greess, H.; Anders, K. [Erlangen-Nuernberg Univ. (Germany). Inst. fuer Diagnostische Radiologie

    2005-07-01

    Recurrent pains of the temporomandibular joint represent a frequent symptom with numerous different causes. CT and MRI can reliably show the cause of these disorders and therefore have substituted conventional X-ray imaging. Modern multi-slice-CT (MSCT) allows for examination of the skull base including the mandible in a very short time with thinnest slice collimation (0.75 mm). With 2D- and 3D- reformations reconstructed out of this volume data set in parasagittal, coronal or any other arbitrary slice orientation excellent imaging of fractures and bony changes of arthrosis as well as benign and malignant tumors of the temporomandibular joint can be performed. MRI offers very good soft tissue contrast in order to visualize the intra-articular disc, the ligaments and muscles, as well the possibility to acquire cross sectional images in any user-defined orientation. MRI is the method of choice to diagnose 'internal derangement', particularly displacement of the intra-articular disc and inflammatory disease of the temporomandibular joint. The present paper will provide diagnostic strategies for the use of MSCT or MRI imaging concerning the different causes of disorders to the temporomandibular joint. (orig.)

  2. Accuracy of high-resolution CT in distinguishing between Pneumocystis carinii pneumonia and non-Pneumocystis carinii pneumonia in AIDS patients

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo, A.; Mauleon, S.; Andreu, J.; Caceres, J. [Department of Radiology, Hospital General Universitari Vall d' Hebron, Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, Paseo Vall d' Hebron 119-129, 08035 Barcelona (Spain); Falco, V.; Crespo, M.; Ribera, E.; Pahissa, A. [Department of Medicine, Service of Infectious Diseases, Hospital General Universitari Vall d' Hebron, Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, Paseo Vall d' Hebron 119-129, 08035 Barcelona (Spain)

    2003-05-01

    The aim of this study was to assess the value of high-resolution CT in distinguishing between Pneumocystis carinii and non-Pneumocystis carinii pneumonia (PCP) in patients HIV-positive and high risk to have PCP. We performed a prospective study in 30 patients with <200 CD4 lymphocytes, clinical symptoms of pulmonary disease and chest X-ray non-conclusive for pulmonary infection. Evaluated CT findings included ground-glass opacities, reticulation, tree-in-bud appearance, consolidation, cystic lesions, bronchiectasis and lymphadenopathies. The diagnosis of ''examination suggestive of PCP'' was applied to cases showing a diffuse or predominant ground-glass pattern in the upper fields, associated or not with reticulations and small cystic lesions. The sensitivity, specificity, positive predictive value and negative predictive value of high-resolution computed tomography (HRCT) for the diagnosis of PCP was 100, 83.3, 90.5 and 100%, respectively. Pneumocystis carinii pneumonia was not demonstrated in any of the cases classified as ''examination not suggestive of PCP''. Significant small airway disease was not observed in any of the PCP cases. We conclude that HRCT is a reliable method for differentiating PCP from other infectious processes in HIV-positive patients and a good method to rule our PCP. Its inclusion in the diagnostic algorithm of lung infections is justified in these patients. (orig.)

  3. Diagnostic accuracy of low-dose 256-slice multi-detector coronary CT angiography using iterative reconstruction in patients with suspected coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Yang; Ma, Yue; Wang, Yuke; Yu, Mei; Guo, Qiyong [Shengjing Hospital of China Medical University, Department of Radiology, Shenyang (China); Fan, Weipeng [Central Hospital of Anshan, Department of Radiology, Anshan (China); Vembar, Mani [CT Clinical Science Philips Healthcare, Cleveland, OH (United States)

    2014-01-15

    To evaluate the accuracy of low-dose coronary CTA with iterative reconstruction (IR) in the diagnosis of coronary artery disease (CAD) in patients with suspected CAD. Ninety-six patients with suspected CAD underwent low-dose prospective electrocardiogram-gated coronary CTA, with images reconstructed using IR. Image quality (IQ) of coronary segments were graded on a 4-point scale (4, excellent; 1, non-diagnostic). With invasive coronary angiography (ICA) considered the ''gold standard'', the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of coronary CTA were calculated on segment-, vessel- and patient-based levels. The patient data were divided into two groups (Agatston scores of ≥ 400 and <400). The differences in diagnostic performance between the two groups were tested. Diagnostic image quality was found in 98.1 % (1,232/1,256) of segments. The sensitivity, specificity, PPV, NPV and accuracy were 90.8 %, 95.3 %, 81.8 %, 97.8 % and 94.3 % (segment-based) and 97.2 %, 83.3 %, 94.6 %, 90.9 % and 93.8 % (patient-based). Significant differences between the two groups were seen in specificity, PPV and accuracy (92.1 % vs. 97.9 %, 76.0 % vs. 86.7 %, 91.7 % vs. 96.6 %, P < 0.05; segment-based). The average effective dose was 1.30 ± 0.15 mSv. Low-dose prospective coronary CTA with IR can acquire satisfactory image quality and show high diagnostic accuracy in patients with suspected CAD; however, blooming continues to pose a challenge in severely calcified segments. (orig.)

  4. Diagnostic accuracy of dual-source CT coronary angiography in a population unselected for degree of coronary artery calcification and without heart rate modification

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C.-J., E-mail: bcjlin@gmail.co [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); National Yang-Ming University School of Medicine, Taipei, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Hsu, J.-C. [National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Division of Cardiovascular Medicine, Far Eastern Memorial Hospital, Pan-Chiao City, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Lai, Y.-J. [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); National Yang-Ming University School of Medicine, Taipei, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Wang, K.-L. [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); Department of Radiological Technology, Yuanpei University, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Lee, J.-Y. [Department of Medical Imaging, Far Eastern Memorial Hospital, Pan-Chiao, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Li, A.-H. [Division of Cardiovascular Medicine, Far Eastern Memorial Hospital, Pan-Chiao City, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China); Chu, S.-H. [Division of Cardiovascular Surgery, Cardiovascular Center, Far Eastern Memorial Hospital, Pan-Chiao City, Taiwan (China); National Taiwan University College of Medicine, Taipei, Taiwan (China)

    2010-02-15

    Aim: To assess the ability of coronary angiography performed using dual-source computed tomography (DSCT) to evaluate coronary artery disease (CAD) in a population with unselected heart rates and extensive coronary calcification. Materials and methods: Forty-four patients at intermediate to high risk for CAD underwent both DSCT coronary angiography and invasive coronary angiography (ICA) within 30 days. No beta blockers were administered prior to imaging. Image quality and quantitatively stenosis of all coronary segments with a diameter >=1.5 mm were accessed. Patients were stratified according to mean heart rate (<70 versus >=70 bpm) and heart rate variability (<10 versus >=10 bpm). DSCT detection of coronary stenosis by segment, vessel, and patient characteristics were compared to the reference standard of ICA. Results: Diagnostic accuracy for all patients was high regarding sensitivity (97%), positive predictive value (PPV, 84.2%), and negative predictive value (NPV, 83.3%) but low regarding specificity (45.5%) with a moderate interobserver agreement (Kappa = 0.50). The accuracy for vessel-based diagnosis was high regarding sensitivity (96.6%), specificity (80.8%), PPV (80.3%), and NPV (96.7%). The segment-based diagnostic results revealed a moderate interobserver agreement for image quality and sensitivity, specificity, PPV and NPV for all segments of 66.9, 97.8, 90.8, and 89.9%, respectively. Conclusion: DSCT coronary angiography has high diagnostic accuracy in assessing CAD among patients at intermediate to high risk without using heart rate-modulating premedication. DSCT is not superior to ICA for diagnosis of calcified segments.

  5. Accuracy and safety of intraoperative CT-assisted placement of pedicle screw%术中CT辅助下椎弓根螺钉置入的精确性和安全性评估

    Institute of Scientific and Technical Information of China (English)

    潘冬生; 宋振全; 赵明光; 张海松; 陆宇; 金振野

    2016-01-01

    Objective To assess the safety and accuracy of intraoperative CT assisted-placement of pedicle screw in the patients with spinal disorders. Methods The clinical data of 39 patients with spinal disorders, who underwent intraoperative CT-assisted placement of pedicle screws in our hospital from May, 2014 through May, 2015, were analyzed retrospectively. The accuracy of pedicle screw placement was assessed by Gertzbein-Robbins classification after the surgery. The safety of pedicle screw fixation was assessed by the postoperative complications. Results A total of 112 pedicle screws were placed in the spines in 39 patients and the placements of 38 screws of them were adjusted according to intraoperative CT findings. Of 112 screws, 105 were placed in the pedicles, 5 by grade 1 pedicle breach, and 2 by grad 2 pedicle breach according to Gertzbein-Robbins classification of pedicle screw placement accuracy. Two screws breached the medical pedicle walls, 4 breached the lateral walls and 1 breached inferolateral pedicle wall. The postoperative complications included surgical site infections in 4 patients, cerebrospinal fluid leaks in 2 and injury to the nerve in 1. No complication was directly related to the screws placement. No patient required reoperation due to the misplacement of the pedicle screws. Conclusions The accuracy and safety of pedicle screw placement can be enhanced in the patients with spinal disorders by intraoperative CT scanning which may be help the surgeon adjust the improper pedicle screw placement in time.%目的 评估术中CT辅助下椎弓根固定技术的安全性和准确性.方法 回顾性分析2014年5月至2015年5月术中CT辅助下椎弓根固定手术治疗的39例脊柱脊髓疾病患者的临床资料,其中脊柱脊髓损伤6例,颅颈交界区畸形6例,脊柱退行性变14例,脊柱脊髓肿瘤13例;术后应用Gertzbein-Robbins分级评价螺钉植入的精确性.结果 椎弓根螺钉固定总数为112枚,术中根据CT影像

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Investigating CT to CBCT image registration for head and neck proton therapy as a tool for daily dose recalculation

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Guillaume, E-mail: g.landry@lmu.de [Department of Medical Physics, Ludwig-Maximilians-University, Munich D85748, Germany and Department of Radiation Oncology, Ludwig-Maximilians-University, Munich D81377 (Germany); Nijhuis, Reinoud; Thieke, Christian; Reiner, Michael; Ganswindt, Ute; Belka, Claus [Department of Radiation Oncology, Ludwig-Maximilians-University, Munich D81377 (Germany); Dedes, George; Handrack, Josefine; Parodi, Katia [Department of Medical Physics, Ludwig-Maximilians-University, Munich D85748 (Germany); Janssens, Guillaume; Orban de Xivry, Jonathan [ICTEAM, Université Catholique de Louvain, Louvain-La-Neuve B1348 (Belgium); Kamp, Florian; Wilkens, Jan J. [Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich D81675, Germany and Physik-Department, Technische Universität München, Garching D85748 (Germany); Paganelli, Chiara; Riboldi, Marco; Baroni, Guido [Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano, Milan 20133 (Italy)

    2015-03-15

    Purpose: Intensity modulated proton therapy (IMPT) of head and neck (H and N) cancer patients may be improved by plan adaptation. The decision to adapt the treatment plan based on a dose recalculation on the current anatomy requires a diagnostic quality computed tomography (CT) scan of the patient. As gantry-mounted cone beam CT (CBCT) scanners are currently being offered by vendors, they may offer daily or weekly updates of patient anatomy. CBCT image quality may not be sufficient for accurate proton dose calculation and it is likely necessary to perform CBCT CT number correction. In this work, the authors investigated deformable image registration (DIR) of the planning CT (pCT) to the CBCT to generate a virtual CT (vCT) to be used for proton dose recalculation. Methods: Datasets of six H and N cancer patients undergoing photon intensity modulated radiation therapy were used in this study to validate the vCT approach. Each dataset contained a CBCT acquired within 3 days of a replanning CT (rpCT), in addition to a pCT. The pCT and rpCT were delineated by a physician. A Morphons algorithm was employed in this work to perform DIR of the pCT to CBCT following a rigid registration of the two images. The contours from the pCT were deformed using the vector field resulting from DIR to yield a contoured vCT. The DIR accuracy was evaluated with a scale invariant feature transform (SIFT) algorithm comparing automatically identified matching features between vCT and CBCT. The rpCT was used as reference for evaluation of the vCT. The vCT and rpCT CT numbers were converted to stopping power ratio and the water equivalent thickness (WET) was calculated. IMPT dose distributions from treatment plans optimized on the pCT were recalculated with a Monte Carlo algorithm on the rpCT and vCT for comparison in terms of gamma index, dose volume histogram (DVH) statistics as well as proton range. The DIR generated contours on the vCT were compared to physician-drawn contours on the rpCT

  8. The detection accuracy of cone beam CT for osseous defects of the temporomandibular joint: a systematic review and meta-analysis

    Science.gov (United States)

    Ma, Ruo-han; Yin, Shuang; Li, Gang

    2016-01-01

    The purpose of this review was to evaluate whether cone-beam computed tomography (CBCT) is reliable for the detection of bone changes of the temporomandibular joint (TMJ). Studies collected from the PubMed, Web of Science, Cochrane Library, ScienceDirect, Embase, Wanfang and CNKI databases were searched, and the publishing time was limited from January 1990 to December 2015. Eight studies (23 experimental research groups) were eventually included for further analysis. The pooled sensitivity was 0.67 and the pooled specificity was 0.87, which leads to a relatively large area (0.84) under the Receiver Operating Characteristic (ROC) curve. The related pooled positive likelihood ratio (+LR) and the pooled negative likelihood ratio (−LR) were 5.2 and 0.38, respectively. The subgroup analysis was conducted for four subgroups categorized by voxel size (≤0.2; >0.2, ≤0.3; >0.3, ≤0.4; >0.4, and ≤0.5 (mm)), and the “>0.4, ≤0.5” subgroup had a higher pooled sensitivity and pooled specificity than the other groups. The present study demonstrates that CBCT has a relatively high diagnostic accuracy for TMJ bone changes, although its reliability is limited. Voxel size did not play a role in the accuracy of CBCT. PMID:27708375

  9. Diagnostic accuracy of colour Doppler ultrasonography, CT angiography and blood-pool-enhanced MR angiography in assessing carotid stenosis: a comparative study with DSA in 170 patients.

    Science.gov (United States)

    Anzidei, M; Napoli, A; Zaccagna, F; Di Paolo, P; Saba, L; Cavallo Marincola, B; Zini, C; Cartocci, G; Di Mare, L; Catalano, C; Passariello, R

    2012-02-01

    This study was undertaken to prospectively evaluate the diagnostic performance of colour Doppler ultrasonography (CDUS), first-pass (FP) and steady-state (SS) contrast-enhanced magnetic resonance angiography (MRA) and computed tomography angiography (CTA) of the carotid arteries using digital subtraction angiography (DSA) as the reference standard. A total of 170 patients with previous cerebrovascular events and suspected carotid artery stenoses underwent CDUS, blood-pool MRA, CTA and DSA. Accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for CDUS, FP MRA, SS MRA and CTA. The McNemar and Wilcoxon tests and receiver operating characteristic (ROC) curve analysis were used to determine significant differences (p<0.05) between the diagnostic performances of the four modalities, and the degree of stenosis was compared using linear regression. A total of 336 carotid bifurcations were studied. The area under the curve (AUC) for degree of stenosis was: CDUS 0.85±0.02, FP MRA 0.982±0.005, SS MRA 0.994±0.002 and CTA 0.997±0.001. AUC analysis showed no statistically significant difference between CTA and MRA (p=0.0174) and a statistically significant difference between CDUS and the other techniques (p<0.001). Plaque morphology analysis showed no significant difference between CTA and SS MRA; a significant difference was seen between CTA and SS MRA versus FP MRA (p=0.04) and CDUS (p=0.038). Plaque ulceration analysis showed a statistically significant difference between MRA and CTA (0.04< p<0.046) versus CDUS (p=0.019). CTA is the most accurate technique for evaluating carotid stenoses, with a slightly better performance than MRA (97% vs. 95% for SS MRA and 92% for FP MRA) and a greater accuracy than CDUS (97% vs. 76%). Blood-pool contrast-enhanced SS sequences offer improved evaluation of degree of stenosis and plaque morphology with accuracy substantially identical to CTA.

  10. Solitary pulmonary nodule and {sup 18}F-FDG PET/CT. Part 2: accuracy, cost-effectiveness, and current recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Mosmann, Marcos Pretto; Borba, Marcelle Alves; Macedo, Francisco Pires Negromonte de; Liguori, Adriano de Araujo Lima; Villarim Neto, Arthur [Liga Norte-Riograndense Contra o Cancer, Natal, RN (Brazil); Lima, Kenio Costa de, E-mail: mosmann@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Saude Coletiva

    2016-03-15

    A solitary pulmonary nodule is a common, often incidental, radiographic finding. The investigation and differential diagnosis of solitary pulmonary nodules remain complex, because there are overlaps between the characteristics of benign and malignant processes. There are currently many strategies for evaluating solitary pulmonary nodules. The main objective is to identify benign lesions, in order to avoid exposing patients to the risks of invasive methods, and to detect cases of lung cancer accurately, in order to avoid delaying potentially curative treatment. The focus of this study was to review the evaluation of solitary pulmonary nodules, to discuss the current role of {sup 18}F fluorodeoxyglucose positron-emission tomography, addressing its accuracy and cost-effectiveness, and to detail the current recommendations for the examination in this scenario. (author)

  11. SU-D-207-06: Clinical Validations of Shading Correction for Cone-Beam CT Using Planning CT as a Prior

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, T; Zhu, L [Georgia Institute of Technology, Atlanta, GA (Georgia); Wei, J [Landauer Medical Physics, Newnan, GA (United States)

    2015-06-15

    Purpose: Current cone-beam CT (CBCT) images contain severe shading artifacts mainly due to scatter, hindering their quantitative use in current radiation therapy. We have previously proposed an effective shading correction method for CBCT using planning CT (pCT) as prior knowledge. In this work, we investigate the method robustness via statistical analyses on studies of a large patient group and compare the performance with that of a state-of-the-art method implemented on the current commercial radiation therapy machine -- the Varian Truebeam system. Methods: Since radiotherapy patients routinely undergo multiple-detector CT (MDCT) scans in the planning procedure, we use the high-quality pCT as “free” prior knowledge for CBCT image improvement. The CBCT image with no correction is first spatially registered with the pCT. Primary CBCT projections are estimated via forward projections of the registered image. The low frequency errors in the projections, which stem from mainly scatter, are estimated by filtering the difference between original line integral and the estimated scatter projections. The corrected CBCT image is then reconstructed from the scatter corrected projections. The proposed method is evaluated on 40 cancer patients. Results: On all patient images, we compare errors on CT number, spatial non-uniformity (SNU) and image contrast, using pCT as the ground truth. T-tests show that our algorithm improves over the Varian method on CBCT accuracies of CT number and SNU with 90% confident. The average CT number error is reduced from 54.8 HU on the Varian method to 40.9 HU, and the SNU error is reduced from 7.7% to 3.8%. There is no obvious improvement on image contrast. Conclusion: Large-group patient studies show that the proposed pCT-based algorithm outperforms the Varian method of the Truebeam system on CBCT shading correction, by providing CBCT images with higher CT number accuracy and greater image uniformity.

  12. 18F-FDG-PET/CT parameters as imaging biomarkers in oral cavity squamous cell carcinoma, is visual analysis of PET and contrast enhanced CT better than the numbers?

    Energy Technology Data Exchange (ETDEWEB)

    Kendi, A.Tuba, E-mail: ayse.kendi@emory.edu [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA (United States); Corey, Amanda [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA (United States); Magliocca, Kelly R. [Department of Pathology, Emory University, Atlanta, GA (United States); Nickleach, Dana C. [Biostatistics & Bioinformatics Shared Resource at Winship Cancer Institute of Emory University, Atlanta, GA (United States); Galt, James [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA (United States); Switchenko, Jeffrey M. [Biostatistics & Bioinformatics Shared Resource at Winship Cancer Institute of Emory University, Atlanta, GA (United States); El-Deiry, Mark W.; Wadsworth, J. Trad [Otolaryngology Head and Neck Surgery, Emory University, Atlanta, GA (United States); Hudgins, Patricia A. [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA (United States); Saba, Nabil F. [Hematology Oncology, Winship Cancer Institute of Emory University, Atlanta, GA (United States); Schuster, David M. [Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA (United States)

    2015-06-15

    Highlights: • Highlights of our study were the significant association of higher T stage of oral cavity squamous cell carcinoma with PET/CT parameters. • This could be an important finding in cases where it is difficult to decide on T stage by CT only. • We found a significant association between ring/heterogeneous enhancement pattern of (either primary or nodal or both) oral cavity squamous cell carcinoma at contrast enhanced CT and poor prognosis. • This could be related to hypoxia, which is a known reason for therapy resistance. Hence therapies can be tailored in the feature depending on enhancement pattern on contrast enhanced CT. - Abstract: Purpose: This study was designed to seek associations between positron emission tomography/computed tomography (PET/CT) parameters, contrast enhanced neck computed tomography (CECT) and pathological findings, and to determine the potential prognostic value of PET/CT and CECT parameters in oral cavity squamous cell carcinoma (OCSCC). Materials and method: 36 OCSCC patients underwent staging PET/CT and 30/36 of patients had CECT. PET/CT parameters were measured for the primary tumor and the hottest involved node, including maximum, mean, and peak standardized uptake values (SUV max, SUV mean, and SUV peak), metabolic tumor volume (MTV), total lesion glycolysis (TLG), standardized added metabolic activity (SAM), and normalized standardized added metabolic activity (N SAM). Qualitative assessment of PET/CT and CECT were also performed. Pathological outcomes included: perineural invasion, lymphovascular invasion, nodal extracapsular spread, grade, pathologic T and N stages. Multivariable logistic regression models were fit for each parameter and outcome adjusting for potentially confounding variables. Multivariable Cox proportional hazards models were used for progression free survival (PFS), locoregional recurrence free survival (LRFS), overall survival (OS) and distant metastasis free survival (DMFS). Results: In

  13. Performance evaluation of the General Electric eXplore CT 120 micro-CT using the vmCT phantom

    Energy Technology Data Exchange (ETDEWEB)

    Bahri, M.A., E-mail: M.Bahri@ulg.ac.be [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); Warnock, G.; Plenevaux, A. [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); Choquet, P.; Constantinesco, A. [Biophysique et Medecine Nucleaire, Hopitaux universitaires de Strasbourg, Strasbourg (France); Salmon, E.; Luxen, A. [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); Seret, A. [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); ULg-Liege University, Experimental Medical Imaging, Liege (Belgium)

    2011-08-21

    The eXplore CT 120 is the latest generation micro-CT from General Electric. It is equipped with a high-power tube and a flat-panel detector. It allows high resolution and high contrast fast CT scanning of small animals. The aim of this study was to compare the performance of the eXplore CT 120 with that of the eXplore Ultra, its predecessor for which the methodology using the vmCT phantom has already been described . The phantom was imaged using typical a rat (fast scan or F) or mouse (in vivo bone scan or H) scanning protocols. With the slanted edge method, a 10% modulation transfer function (MTF) was observed at 4.4 (F) and 3.9-4.4 (H) mm{sup -1} corresponding to 114 {mu}m resolution. A fairly larger MTF was obtained by the coil method with the MTF for the thinnest coil (3.3 mm{sup -1}) equal to 0.32 (F) and 0.34 (H). The geometric accuracy was better than 0.3%. There was a highly linear (R{sup 2}>0.999) relationship between measured and expected CT numbers for both the CT number accuracy and linearity sections of the phantom. A cupping effect was clearly seen on the uniform slices and the uniformity-to-noise ratio ranged from 0.52 (F) to 0.89 (H). The air CT number depended on the amount of polycarbonate surrounding the area where it was measured; a difference as high as approximately 200 HU was observed. This hindered the calibration of this scanner in HU. This is likely due to the absence of corrections for beam hardening and scatter in the reconstruction software. However in view of the high linearity of the system, the implementation of these corrections would allow a good quality calibration of the scanner in HU. In conclusion, the eXplore CT 120 achieved a better spatial resolution than the eXplore Ultra (based on previously reported specifications) and future software developments will include beam hardening and scatter corrections that will make the new generation CT scanner even more promising.

  14. Accuracy and the influence of marrow fat on quantitative CT and dual-energy X-ray absorptiometry measurements of the femoral neck in vitro.

    Science.gov (United States)

    Kuiper, J W; van Kuijk, C; Grashuis, J L; Ederveen, A G; Schütte, H E

    1996-01-01

    Bone mineral measurements with quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA) were compared with chemical analysis (ChA) to determine (1) the accuracy and (2) the influence of bone marrow fat. Total bone mass of 19 human femoral necks in vitro was determined with QCT and DXA before and after defatting. ChA consisted of defatting and decalcification of the femoral neck samples for determination of bone mineral mass (BmM) and amount of fat. The mean BmM was 4.49 g. Mean fat percentage was 37.2% (23.3%-48.5%). QCT, DXA and ChA before and after defatting were all highly correlated (r > 0.96, p defatting the QCT values were on average 0.35 g less than BmM and the DXA values were on average 0.65 g less than BmM. After defatting, all bone mass values increased; QCT values were on average 0.30 g more than BmM and DXA values were 0.29 g less than BmM. It is concluded that bone mineral measurements of the femoral neck with QCT and DXA are highly correlated with the chemically determined bone mineral mass and that both techniques are influenced by the femoral fat content.

  15. Influence of Head Motion on the Accuracy of 3D Reconstruction with Cone-Beam CT: Landmark Identification Errors in Maxillofacial Surface Model

    Science.gov (United States)

    Song, Jin-Myoung; Cho, Jin-Hyoung

    2016-01-01

    Purpose The purpose of this study was to investigate the influence of head motion on the accuracy of three-dimensional (3D) reconstruction with cone-beam computed tomography (CBCT) scan. Materials and Methods Fifteen dry skulls were incorporated into a motion controller which simulated four types of head motion during CBCT scan: 2 horizontal rotations (to the right/to the left) and 2 vertical rotations (upward/downward). Each movement was triggered to occur at the start of the scan for 1 second by remote control. Four maxillofacial surface models with head motion and one control surface model without motion were obtained for each skull. Nine landmarks were identified on the five maxillofacial surface models for each skull, and landmark identification errors were compared between the control model and each of the models with head motion. Results Rendered surface models with head motion were similar to the control model in appearance; however, the landmark identification errors showed larger values in models with head motion than in the control. In particular, the Porion in the horizontal rotation models presented statistically significant differences (P CBCT scan might cause landmark identification errors on the 3D surface model in relation to the direction of the scanner rotation. Clinicians should take this into consideration to prevent patient movement during CBCT scan, particularly horizontal movement. PMID:27065238

  16. FDG-PET-CT for staging of high-risk breast cancer patients reduces the number of further examinations: A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Jager, Jos; Houben, Ruud; Ruysscher, Dirk de; Lambin, Philippe (MAASTRO Clinic, Postbus 1345, 6202 NA Maastricht (Netherlands)), E-mail: jos.jager@maastro.nl; Boersma, Liesbeth J.; Keymeulen, Kristien (Maastricht Univ. Medical Center, Dept. of Surgery, Maastricht (Netherlands)); Beets-Tan, Regina G.H. (Maastricht Univ. Medical Center, Dept. of Radiology, Maastricht (Netherlands)); Hupperets, Pierre (Maastricht Univ. Medical Center, Dept. of Medical Oncology, Maastricht (Netherlands)); Kroonenburgh, Marinus van (Maastricht Univ. Medical Center, Dept. of Nuclear Medicine, Maastricht (Netherlands))

    2010-02-15

    Aim. To determine the additional value of FDG-PET-CT as compared to conventional staging (CS) in high-risk breast cancer patients. Patients and methods. Thirty-one high-risk breast cancer patients, 14 of whom had recurrent breast cancer, were included in this study, which took place between June 2005 and March 2008. None of the patients had clinical signs of distant metastases. FDG-PET-CT scanning was added to CS, which consisted of a chest x-ray, liver ultrasonography or CT, and bone scintigraphy. Median follow-up was 17 months (6-41 months). FDG-PET-CT was considered to have additional value to CS if it led to a change in treatment plan or if it made additional examinations to confirm or deny findings on CS unnecessary. Results. FDG-PET-CT was considered to have additional value to CS in 13 patients (42% [95% CI: 23-61]). In five patients (16% [95% CI: 1-31]), FDG-PET-CT led to a change in treatment plan by identifying nodal metastases in the internal mammary chain (IMC; N = 3) or in the mediastinum (N = 2). In nine patients (29% [95% CI: 11-47]), FDG-PET-CT would have prevented the need for additional examinations; in seven of these nine patients, distant metastases were suggested in bone or liver on CS, but these did not show FDG uptake. Conclusions. FDG-PET-CT was found to have additional value to CS in 42% of the patients. To optimize cost-effectiveness, the main challenge now is to improve the selection of patients in whom FDG-PET-CT has additional value to CS

  17. Diagnostic accuracy of 16-row multislice CT angiography in the evaluation of coronary segments; Accuratezza diagnostica della coronarografia-TC a 16 strati nella valutazione dei segmenti coronarici

    Energy Technology Data Exchange (ETDEWEB)

    Cademartiri, Filippo [Erasmus Medical Center, Rotterdam (Netherlands). Dipartimento di Radiologia; Mollet, Nico R. [Erasmus Medical Center, Rotterdam (Netherlands). Dipartimento di Cardiologia; Runza, Giuseppe [Palermo Univ., Palermo (Italy). DIBIMEL Sezione di Scienze Radiologiche] [and others

    2005-02-01

    Purpose: To evaluate the diagnostic accuracy of 16-row multislice spiral computed tomography coronary angiography (16-MSCT-CA) for the non-invasive assessment of significant coronary artery stenosis. Materials and methods: We enrolled 40 patients (36 male, aged {+-} 11 yrs) with suspected obstructive coronary artery disease and a heart rate <65 bpm during the scan. The 16-MSCT-CA (Sensation 16, Siemens, Forcheim, Germany) was performed with electrocardiographic-gated technique after the intravenous administration of 100 ml of iodinated contrast material followed by a saline bolus chaser. The scan parameters were: collimation 16x0.75 mm, rotation time 0.42 s, feed/rot. 3 mm (pitch 0.25), 120 kVp, 500 mAs. All coronary segments {>=}2 mm in diameter were evaluated by two independent observers for the presence of significant coronary artery stenosis ({>=}50%). Consensus reading was compared to quantitative coronary angiography. Results: The average heart rate was 55{+-}6 bpm. Of the 428 segments of {>=}2.0 diameter 92 were significantly diseased. Without exclusion of any branches (428), the sensitivity, specificity, positive, and negative predictive values to identify {>=}50% obstructed segments were 95.7% (88/92), 95.8% (322/336). 86.3% (88/102), and 98.8% (322/326), respectively. No occluded left main, left anterior descending, circumflex or right coronary artery segments remained undetected. Conclusions: 16-MSCT-CA in a selected low-heart-rate patient population provides high diagnostic accuracy in the evaluation of significant coronary artery stenosis. [Italian] Scopo: Misurare l'accuratezza diagnostica della coronarografia-TC a 16 strati (16-AC-TCMS) nella valutazione non invasiva delle stenosi coronariche significative. Materiale e metodi: Quaranta pazienti (36 maschi, eta' 59{+-}11 anni) con sospetta malattia coronarica ostruttiva e con frequenza cardiaca durante la scansione <65bpm sono stati arruolati per lo studio . La 16-AC-TCMS (Sensation 16

  18. Influence of Head Motion on the Accuracy of 3D Reconstruction with Cone-Beam CT: Landmark Identification Errors in Maxillofacial Surface Model.

    Directory of Open Access Journals (Sweden)

    Kyung-Min Lee

    Full Text Available The purpose of this study was to investigate the influence of head motion on the accuracy of three-dimensional (3D reconstruction with cone-beam computed tomography (CBCT scan.Fifteen dry skulls were incorporated into a motion controller which simulated four types of head motion during CBCT scan: 2 horizontal rotations (to the right/to the left and 2 vertical rotations (upward/downward. Each movement was triggered to occur at the start of the scan for 1 second by remote control. Four maxillofacial surface models with head motion and one control surface model without motion were obtained for each skull. Nine landmarks were identified on the five maxillofacial surface models for each skull, and landmark identification errors were compared between the control model and each of the models with head motion.Rendered surface models with head motion were similar to the control model in appearance; however, the landmark identification errors showed larger values in models with head motion than in the control. In particular, the Porion in the horizontal rotation models presented statistically significant differences (P < .05. Statistically significant difference in the errors between the right and left side landmark was present in the left side rotation which was opposite direction to the scanner rotation (P < .05.Patient movement during CBCT scan might cause landmark identification errors on the 3D surface model in relation to the direction of the scanner rotation. Clinicians should take this into consideration to prevent patient movement during CBCT scan, particularly horizontal movement.

  19. CT angiography for living kidney donors: accuracy, cause of misinterpretation in studies of renal artery variations%CT血管成像评估活体肾移植供者肾动脉变异的准确性及其误判原因分析

    Institute of Scientific and Technical Information of China (English)

    赵修义; 孙奔; 田军; 孙长凤; 丁伟平; 王杰; 张爱民; 邵亚辉; 汝艳辉

    2014-01-01

    目的 评价活体肾移植供者肾动脉变异的CT血管成像(CTA)准确性,并分析误判原因.方法 308例活体肾移植供者术前均按同一扫描程序行多层螺旋CT(MSCT)检查,记录术前CT诊断结果,并与术中实际肾动脉解剖结构对照,分析计算活体肾移植供者肾动脉变异的CTA准确性;以术中实际情况为标准,针对误判病例术前MSCT资料进一步二次对照分析,总结误判的可能原因.结果 308例供者均成功行供肾手术,术中发现68支副肾动脉,17例肾动脉过早分支;术前MSCT共发现副肾动脉71支,其中5支术中未发现,5例假阳性病例中1例在二次对照分析中鉴别排除;术中所见2支副肾动脉在术前CTA上未鉴别出,在术后二次对照分析中其中1支予以鉴别,另1支仍未发现;术中17例肾动脉过早分支术前MSCT均清晰显示.MSCT诊断副肾动脉及动脉早期分支的准确性分别为98.5%(67/68)和100%(17/17).结论 供者肾动脉变异较常见,CTA能准确显示肾动脉及其变异,可作为术前评价活体肾移植供者肾动脉变异的标准检查方法.影像与移植医师定期阅片沟通对改进外科相关解剖的报告有重要意义.%Objective To assess the diagnostic accuracy of 16-slice multislice CT (MSCT)angiography in the evaluation of arterial variants in our centre by means of a retrospective comparison of the preoperative CT renal angiography and intraoperative findings of all live renal donors during the study period,and to identify potential reporting pitfalls.Method In the study period,308 consecutive live renal donors underwent contrast-enhanced MSCT renal angiography before donor nephrectomy.All MSCT studies were performed by using a 16-slice MSCT scanner with the same protocol.The initial CT results were compared with the operative findings during kidney harvest on the basis of arterial anatomy.The number and major variations of the renal arteries were evaluated.The accuracy of CT for the

  20. Thoracic CT

    Science.gov (United States)

    ... lungs; CT scan - chest Images CT scan Thyroid cancer - CT scan Pulmonary nodule, solitary - CT scan Lung mass, right upper ... Chest Injuries and Disorders CT Scans Emphysema Lung Cancer Lung Diseases Pleural Disorders Pneumonia Pulmonary Embolism Tuberculosis Browse the Encyclopedia A.D.A. ...

  1. Accuracy of the CT-estimated weight of the right hepatic lobe prior to living related liver donation (LRLD) for predicting the intraoperatively measured weight of the graft; Vorraussagegenauigkeit der praeoperativen CT-gestuetzten Gewichtsbestimmung des rechten Leberlappens bezueglich des intraoperativen Transplantatgewichts bei Leberlappen-Lebendspendern

    Energy Technology Data Exchange (ETDEWEB)

    Lemke, A.-J.; Brinkmann, M.; Felix, R. [Universitaetsklinikum Charite, Berlin (Germany). Klinik fuer Strahlenheilkunde; Pascher, A.; Steinmueller, T.; Settmacher, U.; Neuhaus, P. [Universitaetsklinikum Charite, Berlin (Germany). Klinik fuer Allgemein-, Viszeral- und Transplantationschirurgie

    2003-09-01

    Purpose: Due to the shortage of cadaver donors, living related liver donation (LRLD) has emerged as an alternative to cadaver donation. The expected graft weight is one of the main determinants for donor selection. This study investigates the accuracy of preoperatively performed CT-volumetry to predict the actual weight of the right liver lobe graft. Materials and methods: In a prospective study the weight of the right hepatic lobe was calculated by volumetric analysis based on CT in 33 patients (21 females, 12 males, mean age 42.1 years, median age 41 years) prior to living related liver donation. Graft weight was calculated as the product of CT-based graft volume and 1.00 g/ml (the approximated density of healthy liver parenchyma). The calculated weight was compared with the intraoperatively measured weight of the harvested right hepatic lobe. The difference was used to determine a correction factor for estimating the actual graft weight. Results: Based on the assumption of a parenchymal density of 1.00 g/ml, the preoperatively estimated graft weight (mean 980 g {+-} 168 g) deviated + 33% from the intraoperatively measured right hepatic lobe weight (mean 749 g {+-} 170 g). By reducing the preoperatively predicted weight of the right hepatic lobe with a correction factor of 0.75, the actual graft weight can be calculated. [German] Ziel: Vor dem Hintergrund des bestehenden Mangels an Spenderorganen stellt die Leberlappen-Lebendspende eine Alternative zur Leichenspende dar. Massgeblich fuer die Auswahl des Spenders ist das zu erwartende Transplantatgewicht. Ziel der Studie war, die Voraussagegenauigkeit der praeoperativen CT-gestuetzten Gewichtsbestimmung auf Basis einer Volumetrie des rechten Leberlappens bezueglich des intraoperativen Transplantatgewichts zu ueberpruefen. Methodik: In einer prospektiven Studie wurde bei 33 Patienten (21 Frauen, 12 Maennern, mittleres Alter 42,1 Jahre, medianes Alter 41 Jahre) vor Leberlappen-Lebendspende auf der Basis von CT

  2. Fast CT-CT fluoroscopy registration with respiratory motion compensation for image-guided lung intervention

    Science.gov (United States)

    Su, Po; Xue, Zhong; Lu, Kongkuo; Yang, Jianhua; Wong, Stephen T.

    2012-02-01

    CT-fluoroscopy (CTF) is an efficient imaging method for guiding percutaneous lung interventions such as biopsy. During CTF-guided biopsy procedure, four to ten axial sectional images are captured in a very short time period to provide nearly real-time feedback to physicians, so that they can adjust the needle as it is advanced toward the target lesion. Although popularly used in clinics, this traditional CTF-guided intervention procedure may require frequent scans and cause unnecessary radiation exposure to clinicians and patients. In addition, CTF only generates limited slices of images and provides limited anatomical information. It also has limited response to respiratory movements and has narrow local anatomical dynamics. To better utilize CTF guidance, we propose a fast CT-CTF registration algorithm with respiratory motion estimation for image-guided lung intervention using electromagnetic (EM) guidance. With the pre-procedural exhale and inhale CT scans, it would be possible to estimate a series of CT images of the same patient at different respiratory phases. Then, once a CTF image is captured during the intervention, our algorithm can pick the best respiratory phase-matched 3D CT image and performs a fast deformable registration to warp the 3D CT toward the CTF. The new 3D CT image can be used to guide the intervention by superimposing the EM-guided needle location on it. Compared to the traditional repetitive CTF guidance, the registered CT integrates both 3D volumetric patient data and nearly real-time local anatomy for more effective and efficient guidance. In this new system, CTF is used as a nearly real-time sensor to overcome the discrepancies between static pre-procedural CT and the patient's anatomy, so as to provide global guidance that may be supplemented with electromagnetic (EM) tracking and to reduce the number of CTF scans needed. In the experiments, the comparative results showed that our fast CT-CTF algorithm can achieve better registration

  3. A noise-optimized virtual monochromatic reconstruction algorithm improves stent visualization and diagnostic accuracy for detection of in-stent re-stenosis in lower extremity run-off CT angiography.

    Science.gov (United States)

    Mangold, Stefanie; De Cecco, Carlo N; Schoepf, U Joseph; Yamada, Ricardo T; Varga-Szemes, Akos; Stubenrauch, Andrew C; Caruso, Damiano; Fuller, Stephen R; Vogl, Thomas J; Nikolaou, Konstantin; Todoran, Thomas M; Wichmann, Julian L

    2016-12-01

    To evaluate the impact of noise-optimized virtual monochromatic imaging (VMI+) on stent visualization and accuracy for in-stent re-stenosis at lower extremity dual-energy CT angiography (DE-CTA). We evaluated third-generation dual-source DE-CTA studies in 31 patients with prior stent placement. Images were reconstructed with linear blending (F_0.5) and VMI+ at 40-150 keV. In-stent luminal diameter was measured and contrast-to-noise ratio (CNR) calculated. Diagnostic confidence was determined using a five-point scale. In 21 patients with invasive catheter angiography, accuracy for significant re-stenosis (≥50 %) was assessed at F_0.5 and 80 keV-VMI+ chosen as the optimal energy level based on image-quality analysis. At CTA, 45 stents were present. DSA was available for 28 stents whereas 12 stents showed significant re-stenosis. CNR was significantly higher with ≤80 keV-VMI+ (17.9 ± 6.4-33.7 ± 12.3) compared to F_0.5 (16.9 ± 4.8; all p VMI+ (4.90 ± 0.48-4.88 ± 0.63 vs. 4.60 ± 0.66, p = 0.001, 0.0042). Sensitivity, negative predictive value and accuracy for re-stenosis were higher with 80 keV-VMI+ (100, 100, 96.4 %) than F_0.5 (90.9, 94.1, 89.3 %). 80 keV-VMI+ improves image quality, diagnostic confidence and accuracy for stent evaluation at lower extremity DE-CTA. • The impact of noise-optimized virtual monochromatic imaging on stent visualization was assessed. • Virtual monochromatic imaging significantly improves stent lumen visualization and diagnostic confidence. • At 80 keV diagnostic performance for detection of in-stent restenosis was increased. • 80 keV virtual monochromatic images are recommended for stent evaluation of lower extremity vasculature.

  4. A noise-optimized virtual monochromatic reconstruction algorithm improves stent visualization and diagnostic accuracy for detection of in-stent re-stenosis in lower extremity run-off CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); De Cecco, Carlo N.; Yamada, Ricardo T.; Varga-Szemes, Akos; Stubenrauch, Andrew C.; Fuller, Stephen R. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Caruso, Damiano [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Vogl, Thomas J.; Wichmann, Julian L. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Todoran, Thomas M. [Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States)

    2016-12-15

    To evaluate the impact of noise-optimized virtual monochromatic imaging (VMI+) on stent visualization and accuracy for in-stent re-stenosis at lower extremity dual-energy CT angiography (DE-CTA). We evaluated third-generation dual-source DE-CTA studies in 31 patients with prior stent placement. Images were reconstructed with linear blending (F{sub 0}.5) and VMI+ at 40-150 keV. In-stent luminal diameter was measured and contrast-to-noise ratio (CNR) calculated. Diagnostic confidence was determined using a five-point scale. In 21 patients with invasive catheter angiography, accuracy for significant re-stenosis (≥50 %) was assessed at F{sub 0}.5 and 80 keV-VMI+ chosen as the optimal energy level based on image-quality analysis. At CTA, 45 stents were present. DSA was available for 28 stents whereas 12 stents showed significant re-stenosis. CNR was significantly higher with ≤80 keV-VMI+ (17.9 ± 6.4-33.7 ± 12.3) compared to F{sub 0}.5 (16.9 ± 4.8; all p < 0.0463); luminal stent diameters were increased at ≥70 keV (5.41 ± 1.8-5.92 ± 1.7 vs. 5.27 ± 1.8, all p < 0.001) and diagnostic confidence was highest at 70-80 keV-VMI+ (4.90 ± 0.48-4.88 ± 0.63 vs. 4.60 ± 0.66, p = 0.001, 0.0042). Sensitivity, negative predictive value and accuracy for re-stenosis were higher with 80 keV-VMI+ (100, 100, 96.4 %) than F{sub 0}.5 (90.9, 94.1, 89.3 %). 80 keV-VMI+ improves image quality, diagnostic confidence and accuracy for stent evaluation at lower extremity DE-CTA. (orig.)

  5. Effects of the number of markers per haplotype and clustering of haplotypes on the accuracy of QTL mapping and prediction of genomic breeding values

    NARCIS (Netherlands)

    Calus, M.P.L.; Meuwissen, T.H.E.; Windig, J.J.; Knol, E.F.; Schrooten, C.; Vereijken, A.L.J.; Veerkamp, R.F.

    2009-01-01

    The aim of this paper was to compare the effect of haplotype definition on the precision of QTL-mapping and on the accuracy of predicted genomic breeding values. In a multiple QTL model using identity-by-descent (IBD) probabilities between haplotypes, various haplotype definitions were tested i.e. i

  6. 冠状动脉CT造影SYNTAX积分可重复性及准确性研究%The repeatability and accuracy of coronary CT angiography SYNTAX score

    Institute of Scientific and Technical Information of China (English)

    王忠民; 刘煜昊; 朱绍成; 徐予; 朱中玉; 高传玉

    2015-01-01

    目的:分析冠状动脉CT造影SYNTAX积分的可重复性及准确性,为其临床应用奠定基础。方法回顾性分析2012年2月至2013年2月行冠状动脉CT造影及侵入性冠状动脉造影检查的223例患者,分别计算两种方法得出的SYNTAX积分。采用Kappa分析法评价CT冠状动脉造影SYNTAX积分的可重复性。以侵入性冠状动脉造影为金标准,进行配对样本t检验、Spearman's rank test分析及Bland-Altman法分析CT冠状动脉造影SYNTAX积分的准确性。采用双侧P<0.05为差异有统计学意义。结果 CT冠状动脉造影SYNTAX积分读者间及读者内的可重复性极好,K值均>0.75。侵入性冠状动脉造影与CT冠状动脉造影无显著统计学差异(平均值19.44vs.20.40, P=0.295)。相关分析显示两者之间显著正相关(r=0.931,P<0.001)。结论 CT冠状动脉造影SYNTAX积分可重复性好,准确性高。基于CT冠状动脉造影SYNTAX积分值得今后在临床上加以推广应用。%ObjectiveTo determine the repeatability and accuracy of coronary CT angiography SYNTAX score.Methods We evaluated 223 patients that underwent coronary CT angiography (CTA) and subsequent invasive coronary angiography (ICA). Vessel-specific SYNTAX scores, as well as global SYNTAX scores, were calculated from CTA and ICA in blinded fashion by independent and experienced investigators. Kappa analysis was used to analysis the repeatability of CTA. Paired samplet test, Spearman’s rank test analysis and Bland-Altman analysis method was used to analysis the accuracy of CTA. With double sideP0.75. There was no statistically significant difference between ICA and CTA (average: 19.44vs. 20.40,P=0.295). Correlation analysis showed significantly positive correlation between the two methods (r=0.931,P<0.931).ConclusionSYNTAX score derived from CTA demonstrate excellent repeatability and accuracy, which is worthy of clinical application.

  7. (68)Ga-DOTATATE PET/CT in recurrent medullary thyroid carcinoma: a lesion-by-lesion comparison with (111)In-octreotide SPECT/CT and conventional imaging.

    Science.gov (United States)

    Yamaga, Lilian Yuri Itaya; Cunha, Marcelo L; Campos Neto, Guilherme C; Garcia, Marcio R T; Yang, Ji H; Camacho, Cleber P; Wagner, Jairo; Funari, Marcelo B G

    2017-09-01

    The aim of this study was to prospectively compare the detection rate of (68)Ga-DOTATATE PET-CT with (111)In-octreotide SPECT-CT and conventional imaging (CI) in medullary thyroid carcinoma (MTC) patients with increased calcitonin (Ctn) levels but negative CI after thyroidectomy. Fifteen patients with raised Ctn levels and/or CI evidence of recurrence underwent (68)Ga-DOTATATE PET-CT, (111)In-octreotide SPECT-CT and CI. Histopathology, CI and biochemical/clinical/imaging follow-up were used as the reference standard. PET/CT, SPECT/CT and CI were compared in a lesion-based and organ-based analysis. PET/CT evidenced recurrence in 14 of 15 patients. There were 13 true positive (TP), 1 true negative (TN), 1 false positive (FP) and no false negative (FN) cases, resulting in a sensitivity and accuracy of 100% and 93%. SPECT/CT was positive in 6 of 15 cases. There were 6 TP, 2 TN, 7 FN and no FP cases, resulting in a sensitivity of 46% and accuracy of 53%. CI procedures detected tumor lesions in 14 of 15 patients. There were 13 TP, 1TN, 1 FP and no FN cases with a sensitivity of 100% and accuracy of 93%. A significantly higher number of lesions was detected by PET/CT (112 lesions, p = 0.005) and CI (109 lesions, p = 0.005) in comparison to SPECT/CT (16 lesions). There was no significant difference between PET/CT and CI for the total number of detected lesions (p = 0.734). PET/CT detected more lesions than SPECT/CT regardless of the organ. PET/CT detected more bone lesions but missed some neck nodal metastases evidenced by CI. The number of lesions per region demonstrated by PET/CT and CI were similar in the other sites. (68)Ga-DOTATATE PET/CT is superior to (111)In-octreotide SPECT/CT for the detection of recurrent MTC demonstrating a significantly higher number of lesions. (68)Ga-DOTATATE PET/CT showed a superior detection rate compared to CI in demonstrating bone metastases.

  8. Standardizing CT lung density measure across scanner manufacturers.

    Science.gov (United States)

    Chen-Mayer, Huaiyu Heather; Fuld, Matthew K; Hoppel, Bernice; Judy, Philip F; Sieren, Jered P; Guo, Junfeng; Lynch, David A; Possolo, Antonio; Fain, Sean B

    2017-03-01

    Computed Tomography (CT) imaging of the lung, reported in Hounsfield Units (HU), can be parameterized as a quantitative image biomarker for the diagnosis and monitoring of lung density changes due to emphysema, a type of chronic obstructive pulmonary disease (COPD). CT lung density metrics are global measurements based on lung CT number histograms, and are typically a quantity specifying either the percentage of voxels with CT numbers below a threshold, or a single CT number below which a fixed relative lung volume, nth percentile, falls. To reduce variability in the density metrics specified by CT attenuation, the Quantitative Imaging Biomarkers Alliance (QIBA) Lung Density Committee has organized efforts to conduct phantom studies in a variety of scanner models to establish a baseline for assessing the variations in patient studies that can be attributed to scanner calibration and measurement uncertainty. Data were obtained from a phantom study on CT scanners from four manufacturers with several protocols at various tube potential voltage (kVp) and exposure settings. Free from biological variation, these phantom studies provide an assessment of the accuracy and precision of the density metrics across platforms solely due to machine calibration and uncertainty of the reference materials. The phantom used in this study has three foam density references in the lung density region, which, after calibration against a suite of Standard Reference Materials (SRM) foams with certified physical density, establishes a HU-electron density relationship for each machine-protocol. We devised a 5-step calibration procedure combined with a simplified physical model that enabled the standardization of the CT numbers reported across a total of 22 scanner-protocol settings to a single energy (chosen at 80 keV). A standard deviation was calculated for overall CT numbers for each density, as well as by scanner and other variables, as a measure of the variability, before and after the

  9. A 20-year retrospective analysis of CT-based pre-operative identification of pulmonary metastases in patients with osteosarcoma: A single-center review.

    Science.gov (United States)

    Heaton, Todd E; Hammond, William J; Farber, Benjamin A; Pallos, Valerie; Meyers, Paul A; Chou, Alexander J; Price, Anita P; LaQuaglia, Michael P

    2017-01-01

    Cooperative studies support complete metastasectomy in osteosarcoma (OS). Pre-operative CT is used to identify and quantify metastases and can facilitate minimally invasive techniques. Here we assess the accuracy of pre-operative CT compared to findings at thoracotomy and its change over time. We reviewed OS thoracotomies performed at our institution from 1996 to 2015. The number of metastases identified on pre-operative chest CT was compared to the number of metastases seen on pathology (both metastases with viable cells and non-viable, osteoid-only metastases). Eighty-eight patients underwent 161 thoracotomies with a median of 14days (range, 1-85) between CT and surgery, a median of 2 CT-identified lesions (range, 0-15), and a median of 4 resected lesions (range, 1-25). In 56 (34.8%) cases, more metastases were found surgically than were seen on CT, and among these, 34 (21.1%) had a greater number of viable metastases. There was poor overall correlation between CT and pathology findings (Kendall Tau-b=0.506), regardless of CT slice thickness, decade of thoracotomy, or total number of CT-identified lesions. CT accuracy in pre-operatively quantifying OS pulmonary metastases has not improved in recent decades. Consequently, we recommend an open technique with direct lung palpation for complete identification and resection of OS pulmonary metastases. Level IV, retrospective study with no comparison group. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Evaluation of hyperdense renal lesions incidentally detected on single-phase post-contrast CT using dual-energy CT

    Science.gov (United States)

    Park, Jung Jae; Park, Byung Kwan

    2016-01-01

    Objective: To investigate the utility of dual-energy CT (DECT) for differentiating between solid and benign cystic lesions presenting as hyperdense renal lesions incidentally detected on single-phase post-contrast CT. Methods: 90 hyperdense renal lesions incidentally detected on single-phase post-contrast CT were evaluated with follow-up DECT. DECT protocols included true non-contrast (TNC), DE corticomedullary and DE late nephrographic phase imaging. The CT numbers of hyperdense renal lesions were calculated on linearly blended and iodine overlay (IO) images, and the results were compared. Results: In total, 47 benign cystic and 43 solid renal lesions were analyzed. For differentiating between solid and benign cystic lesions on the two phases, the specificity and accuracy of all lesions and lesions  0.05). For all types of lesions ≥1.5 cm, the CT numbers between linearly blended and IO images and between TNC and virtual non-contrast images were not statistically different (p > 0.05). Conclusion: DECT may be useful for differentiating between solid and benign cystic lesions presenting as hyperdense renal lesions incidentally detected on single-phase post-contrast CT, particularly with the size ≥1.5 cm. Advances in knowledge: DECT may be used to characterize hyperdense renal lesions ≥1.5 cm incidentally detected on single-phase post-contrast CT, without the use of TNC images. PMID:27043480

  11. Accuracy and differential bias in copy number measurement of CCL3L1 in association studies with three auto-immune disorders

    NARCIS (Netherlands)

    Carpenter, D.; Walker, S.; Prescott, N.; Schalkwijk, J.; Armour, J.A.

    2011-01-01

    BACKGROUND: Copy number variation (CNV) contributes to the variation observed between individuals and can influence human disease progression, but the accurate measurement of individual copy numbers is technically challenging. In the work presented here we describe a modification to a previously

  12. Effects of the difference in tube voltage of the CT scanner on dose calculation

    CERN Document Server

    Rhee, Dong Joo; Moon, Young Min; Kim, Jung Ki; Jeong, Dong Hyeok

    2015-01-01

    Computed Tomography (CT) measures the attenuation coefficient of an object and converts the value assigned to each voxel into a CT number. In radiation therapy, CT number, which is directly proportional to the linear attenuation coefficient, is required to be converted to electron density for radiation dose calculation for cancer treatment. However, if various tube voltages were applied to take the patient CT image without applying the specific CT number to electron density conversion curve, the accuracy of dose calculation would be unassured. In this study, changes in CT numbers for different materials due to change in tube voltage were demonstrated and the dose calculation errors in percentage depth dose (PDD) and a clinical case were analyzed. The maximum dose difference in PDD from TPS dose calculation and Monte Carlo simulation were 1.3 % and 1.1 % respectively when applying the same CT number to electron density conversion curve to the 80 kVp and 140 kVp images. In the clinical case, the different CT nu...

  13. Accuracy of whole-body low-dose multidetector CT (WBLDCT) versus skeletal survey in the detection of myelomatous lesions, and correlation of disease distribution with whole-body MRI (WBMRI)

    Energy Technology Data Exchange (ETDEWEB)

    Gleeson, T.G. [Mater Misericordiae University Hospital, Department of Radiology and Diagnostic Imaging, Dublin 7 (Ireland)]|[St Paul' s Hospital, Radiology Department, Vancouver, BC (Canada); Moriarty, J.; Shortt, C.P.; O' Connell, M.; Eustace, S.J. [Mater Misericordiae University Hospital, Department of Radiology and Diagnostic Imaging, Dublin 7 (Ireland); Gleeson, J.P. [University of Limerick, Department of Applied Mathemathics and Statistics, Limerick (Ireland); Fitzpatrick, P. [University College Dublin, UCD School of Public Health and Population Science, Dublin 2 (Ireland); Byrne, B. [Mater Misericordiae University Hospital, Department of Medical Physics, Dublin 7 (Ireland); McHugh, J.; O' Gorman, P. [Mater Misericordiae University Hospital, Department of Haematology, Dublin 7 (Ireland)

    2009-03-15

    The aim of the study is to assess the feasibility of whole-body low-dose computed tomography (WBLDCT) in the diagnosis and staging of multiple myeloma and compare to skeletal survey (SS), using bone marrow biopsy and whole-body magnetic resonance imaging (WBMRI; where available) as gold standard. Patients referred over an 18-month period for investigation of suspected multiple myeloma or restaging of myeloma were randomized to undergo one of two WBLDCT protocols using high kVp, low mAs technique (140 kVp, 14 mAs; or 140 kVp, 25 mAs). Recent WBMRI scans were reviewed in 23 cases. Each imaging modality was assessed by two radiologists in consensus and scored from 0-3 (0= normal, 1=1-4 lesions, 2=5-20 lesions, 3{>=}20 lesions/diffuse disease) in ten anatomical areas. Overall stage of disease, image quality score, and the degree of confidence of diagnosis were recorded. Diagnostic accuracy of skeletal survey and WBLDCT were determined using a gold standard of bone marrow biopsy and distribution of disease was compared to WBMRI. Thirty-nine patients were evaluated. WBLDCT identified more osteolytic lesions than skeletal survey with a greater degree of diagnostic confidence and led to restaging in 18 instances (16 upstaged, two downstaged). In those with recent WBMRI, distribution of disease on WBLDCT showed superior correlation with WBMRI when compared with SS. Overall reader impression of stage on WBLDCT showed significant correlation with WBMRI ({kappa}=0.454, p<0.05). WBLDCT provided complementary information to WBMRI in nine patients with normal marrow signal following treatment response, but which were shown to have diffuse residual cortical abnormalities on CT. WBLDCT at effective doses lower than previously reported, is superior to SS at detecting osteolytic lesions and at determining overall stage of multiple myeloma, and provides complementary information to WBMRI. (orig.)

  14. Synthetic Hounsfield units from spectral CT data

    Science.gov (United States)

    Bornefalk, Hans

    2012-04-01

    Beam-hardening-free synthetic images with absolute CT numbers that radiologists are used to can be constructed from spectral CT data by forming ‘dichromatic’ images after basis decomposition. The CT numbers are accurate for all tissues and the method does not require additional reconstruction. This method prevents radiologists from having to relearn new rules-of-thumb regarding absolute CT numbers for various organs and conditions as conventional CT is replaced by spectral CT. Displaying the synthetic Hounsfield unit images side-by-side with images reconstructed for optimal detectability for a certain task can ease the transition from conventional to spectral CT.

  15. Accuracy of the centenarian numbers in Okinawa and the role of the Okinawan diet on longevity: responses to Le Bourg about the article "Exploring the impact of climate on human longevity".

    Science.gov (United States)

    Robine, Jean-Marie; Herrmann, François R; Arai, Yasumichi; Willcox, D Craig; Gondo, Yasuyuki; Hirose, Nobuyoshi; Suzuki, Makoto; Saito, Yasuhiko

    2013-08-01

    This response letter addresses two points raised by le Bourg when discussing our previous paper entitled "Exploring the impact of climate on human longevity". First, the arguments explaining the accuracy of the numbers of centenarian in Okinawa are developed, and second the composition and healthfulness of the traditional Okinawan diet are described as well as the changes in dietary pattern and their impact on longevity. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. PET/CT诊断宫颈癌盆腔淋巴结转移的系统评价%Accuracy of diagnosing para-aortic and pelvic lymph node metastasis in cervical cancer with PET/CT:a meta analysis

    Institute of Scientific and Technical Information of China (English)

    翟亚楠; 郭顺林; 周怀琪; 王平; 王海军

    2011-01-01

    Objective: To review studies focused on diagnosing pelvic and para-aortic lymph node metastasis in cervical cancer with PET/CT, analyse sources of bias and variability and evaluate the diagnostic accuracy with meta analysis. Methods: Searched current literature in database without limiting time and language, evaluated the quality of included studies according to QUADAS(Quality assessment of diagnostic accuracy studies), MetaDisc version 1.40 software was used to pool sensitivity, specificity, positive likelihood ratio (+LR), negative likelihood ratio (-LR) and diagnostic OR, analysed source of heterogeneity with Q-test and draw SROC curves. Results: Nine studies met the inclusion criteria, eight literatures written in English and one in Chinese. 346 cases of cervical cancer (3979 lymph node metastasis) were included, we pooled data with random effects model on lymph nodes level: sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, accuracy and AUC value were 0.58 [95% confidence interval (CI) 0.51 ~0.65], 0.98 (95%CI 0.98~0.99), 0.686(0.464~0.852), 0.936(0.833~0.995), 2.15(7.20~64.24), 0.43(0.32~0.58), 0.900(0.75~0.993), 0.7724, respectively; pooled analysis with random effects model based on patient level: sensitivity, specificity, positive predictive value,negative predictive value, positive likelihood ratio, negative likelihood ratio, accuracy and AUC value were 0.54 (95%CI 0.45~ 0.63), 0.86(95%CI 0.98~0.99), 0.725(0.471~0.923), 0.765(0.615~0.886), 4.58(1.86~11.31), 0.52(0.34~0.80), 0.756(0.620~0.0.897) and 0.8699, respectively. Conclusion: PET/CT has moderate diagnostic value for evaluating pelvic and aortic lymph node metastasis in cervical cancer, which can provide reliable guidance in clincal practice.%目的:系统评价当前研究PET/CT诊断宫颈癌盆腔及主动脉旁淋巴结转移文献的质量并合并分析其准确性.方法:收

  17. Type I and Type II Error Rates and Overall Accuracy of the Revised Parallel Analysis Method for Determining the Number of Factors

    Science.gov (United States)

    Green, Samuel B.; Thompson, Marilyn S.; Levy, Roy; Lo, Wen-Juo

    2015-01-01

    Traditional parallel analysis (T-PA) estimates the number of factors by sequentially comparing sample eigenvalues with eigenvalues for randomly generated data. Revised parallel analysis (R-PA) sequentially compares the "k"th eigenvalue for sample data to the "k"th eigenvalue for generated data sets, conditioned on"k"-…

  18. Detection of walking periods and number of steps in older adults and patients with Parkinsons disease : accuracy of a pedometer and an accelerometry-based method

    NARCIS (Netherlands)

    Dijkstra, Baukje; Zijlstra, Wiebren; Scherder, Erik; Kamsma, Yvo

    The aim of this study was to examine if walking periods and number of steps can accurately be detected by a single small body-fixed device in older adults and patients with Parkinsons disease (PD). Results of an accelerometry-based method (DynaPort MicroMod) and a pedometer (Yamax Digi-Walker

  19. MRI-Based Computed Tomography Metal Artifact Correction Method for Improving Proton Range Calculation Accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Peter C. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Schreibmann, Eduard; Roper, Justin; Elder, Eric; Crocker, Ian [Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia (United States); Fox, Tim [Varian Medical Systems, Palo Alto, California (United States); Zhu, X. Ronald [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dong, Lei [Scripps Proton Therapy Center, San Diego, California (United States); Dhabaan, Anees, E-mail: anees.dhabaan@emory.edu [Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Georgia (United States)

    2015-03-15

    Purpose: Computed tomography (CT) artifacts can severely degrade dose calculation accuracy in proton therapy. Prompted by the recently increased popularity of magnetic resonance imaging (MRI) in the radiation therapy clinic, we developed an MRI-based CT artifact correction method for improving the accuracy of proton range calculations. Methods and Materials: The proposed method replaces corrupted CT data by mapping CT Hounsfield units (HU number) from a nearby artifact-free slice, using a coregistered MRI. MRI and CT volumetric images were registered with use of 3-dimensional (3D) deformable image registration (DIR). The registration was fine-tuned on a slice-by-slice basis by using 2D DIR. Based on the intensity of paired MRI pixel values and HU from an artifact-free slice, we performed a comprehensive analysis to predict the correct HU for the corrupted region. For a proof-of-concept validation, metal artifacts were simulated on a reference data set. Proton range was calculated using reference, artifactual, and corrected images to quantify the reduction in proton range error. The correction method was applied to 4 unique clinical cases. Results: The correction method resulted in substantial artifact reduction, both quantitatively and qualitatively. On respective simulated brain and head and neck CT images, the mean error was reduced from 495 and 370 HU to 108 and 92 HU after correction. Correspondingly, the absolute mean proton range errors of 2.4 cm and 1.7 cm were reduced to less than 2 mm in both cases. Conclusions: Our MRI-based CT artifact correction method can improve CT image quality and proton range calculation accuracy for patients with severe CT artifacts.

  20. 关于提高18F-FDG PET/CT诊断肺部病变准确率探究%The exploration about how to improve the accuracy of 18F-FDG PET/CT in the diagnosis of lung lesions

    Institute of Scientific and Technical Information of China (English)

    王永勇; 付圣灵; 王洁; 徐沁孜; 蔡奕欣; 张霓; 付向宁

    2014-01-01

    目的:通过分析169例肺部病变18F-FDG PET/CT 诊断结果,探究误诊和漏诊的病例特点,探索提高18F-FDG PET/CT诊断肺部病变灵敏度和特异度的方法。方法:收集169例肺部病变并且有明确术后病理诊断患者的病例资料。采用SPSS 18.0软件对结果进行分析。结果:169例病例中,病理诊断为恶性病变的为122例,被 PET/CT 正确诊断的有110例,病理诊断为良性病变的为47例,被 PET/CT 正确诊断的有15例。灵敏度为90.2%,特异度为31.9%,准确率为74.0%。结论:注意对SUV(max)的客观评价,综合病变大小和临床病史以及实验室检查结果进行诊断,才能提高PET/CT诊断的准确度,减少假阳性和假阴性的发生。%Objective In order to improve the diagnosis accuracy , 18F-FDG PET/CT results of 169 cases of lung lesions were analyzed. Methods The data of 169 pathological diagnosed patients were collected. SPSS 18.0 was used for the data analysis. Results In 169 cases, 122 cases were proved malignant by patholog-ical diagnosis, in which 110 cases were correctly diagnosed by PET/CT. 47 cases were proved benign by patho-logical diagnosis, in which 15 cases were correctly diagnosed by PET/CT. The sensitivity was 90.2%, specificity was 31.9%, and the accuracy was 74.0%. Conclusion In order to improve the accuracy rate of PET/CT exam-ination and reduce the existence of false positive cases and false positive cases , we should estimate SUV (max) objectively and diagnose according to the size of the lesion , clinical history and laboratory results.

  1. Evaluating differential nuclear DNA yield rates and osteocyte numbers among human bone tissue types: A synchrotron radiation micro-CT approach.

    Science.gov (United States)

    Andronowski, Janna M; Mundorff, Amy Z; Pratt, Isaac V; Davoren, Jon M; Cooper, David M L

    2017-05-01

    Molecular human identification has conventionally focused on DNA sampling from dense, weight-bearing cortical bone tissue, typically from femora or tibiae. A comparison of skeletal elements from three contemporary individuals demonstrated that elements with high quantities of cancellous bone yielded nuclear DNA at the highest rates, suggesting that preferentially sampling cortical bone may be suboptimal (Mundorff & Davoren, 2014). Despite these findings, the reason for the differential DNA yields between cortical and cancellous bone tissues remains unknown. The primary goal of this work is to ascertain whether differences in bone microstructure can be used to explain differential nuclear DNA yield among bone tissue types observed by Mundorff and Davoren (2014), with a focus on osteocytes and the three-dimensional (3D) quantification of their associated lacunae. Osteocytes and other bone cells are recognized to house DNA in bone tissue, thus examining the density of their lacunae may explain why nuclear DNA yield rates differ among bone tissue types. Lacunae were visualized and quantified using synchrotron radiation-based micro-Computed Tomographic imaging (SR micro-CT). Volumes of interest (VOIs) from cortical and cancellous bone tissues (n=129) were comparatively analyzed from the three skeletons sampled for Mundorff and Davoren's (2014) study. Analyses tested the primary hypothesis that the abundance and density of osteocytes (inferred from their lacunar spaces) vary between cortical and cancellous bone tissue types. Results demonstrated that osteocyte lacunar abundance and density vary between cortical and cancellous bone tissue types, with cortical bone VOIs containing a higher lacunar abundance and density. We found that the osteocyte lacunar density values are independent of nuclear DNA yield, suggesting an alternative explanation for the higher nuclear DNA yields from bones with greater quantities of cancellous bone tissue. The use of SR micro-CT allowed for

  2. 采用锥形束CT测量牙体长度的准确性研究%Investigation of accuracy of premolar length measured by cone beam CT in vivo

    Institute of Scientific and Technical Information of China (English)

    冯驰; 李丛华; 曾兴琪; 王勤花; 郑谦; 邱叶

    2014-01-01

    Objective To investigate the feasibility and accuracy of length measurement of in vivo teeth by using cone beam CT (CBCT). Methods Before orthodontic extraction, 109 vital premolars from 40 participants were scanned by using CBCT and reconstructed by using InVivoDental software. Buccal-lingual sectional images along the long axis of teeth were then acquired, and the crown, root, and tooth length were measured separately. After careful extraction and fixation, the cor-responding length of the same tooth was measured by using a digital caliper. CBCT measurement accuracy was then verified by using physical measurements as reference. Results CBCT and the physical method did not obtain significantly different measurements of the root, crown, and tooth length of experimental teeth (P=0.790, P=0.621, P=0.657, respectively), and the measurements were found to be consistent. The 95% limits of agreement of root, crown, and tooth length were -1.10 mm to 1.13 mm, -1.00 mm to 0.96 mm, and -1.00 mm to 1.05 mm, respectively. Conclusion The difference between CBCT and the physical method was not significant, and good consistency was shown. CBCT could be applied in noninvasive measure-ment of in vivo teeth.%目的: 探索锥形束CT(CBCT)对牙体长度各参数测量的可行性及准确性。方法 通过InVivoDental软件对40例患者109颗活体牙的CBCT扫描数据进行组织分割以及重建,得到目标牙长轴的颊舌向断层图像,测量根长、冠长和牙体全长。相同活体牙经外科拔除后,进行相应参数测量。比较实体测量值和CBCT测量值的差异,检验CBCT测量牙体长度的精确性。结果 实验牙根长、冠长及牙体全长的CBCT测量值与实体测量值的差异无统计学意义(P值分别为0.790、0.621、0.657),两种测量方法差值的95%可信区间分别为(-1.10~1.13)、(-1.00~0.96)、(-1.00~1.05) mm。结论 CBCT对活体牙的根长、冠长及牙体全长的无创测量与实

  3. [18F]Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET)/Computed Tomography (CT) in Suspected Recurrent Breast Cancer

    DEFF Research Database (Denmark)

    Hildebrandt, Malene Grubbe; Gerke, Oke; Baun, Christina;

    2016-01-01

    PURPOSE: To prospectively investigate the diagnostic accuracy of [(18)F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) with dual-time-point imaging, contrast-enhanced CT (ceCT), and bone scintigraphy (BS) in patients with suspected breast cancer recurrence....... PATIENTS AND METHODS: One hundred women with suspected recurrence of breast cancer underwent 1-hour and 3-hour FDG-PET/CT, ceCT, and BS within approximately 10 days. The study was powered to estimate the precision of the individual imaging tests. Images were visually interpreted using a four...... the receiver operating curve and higher sensitivity, specificity, and superior likelihood ratios. CONCLUSION: FDG-PET/CT was accurate in diagnosing recurrence in breast cancer patients. It allowed for distant recurrence to be correctly ruled out and resulted in only a small number of false-positive cases...

  4. Head CT scan

    Science.gov (United States)

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... hold your breath for short periods. A complete scan usually take only 30 seconds to a few ...

  5. Cystic adenomatoid malformation in children: CT histopathological correlation.

    Science.gov (United States)

    Lanza, C; Bolli, V; Galeazzi, V; Fabrizzi, B; Fabrizzi, G

    2007-06-01

    This study was performed to assess the accuracy of computed tomography (CT) in classifying the various types of cystic adenomatoid malformation (CAM) of the lung, as described by Stocker et al., taking histopathology as the gold standard. We retrospectively reviewed six cases of histologically proven CAM. Chest radiography, chest CT and histopathology results were available for all patients. The CT images were reviewed blinded to the histological findings, and attention was paid to the number and size of cysts so as to classify the lesions into the three groups described by Stocker et al. The classification of lesions based on the CT images was then correlated to the histopathological findings. Areas with small-sized cysts (2 cm) were seen in three cases (50%) whereas in the remaining case, the diagnosis was mixed type I and type II CAM. In one patient with type I CAM, an area of low-density consolidation around the cysts was interpreted as CAM in a context of pulmonary sequestration. The CT classification based on Stocker et al.'s categories was in agreement with the histopathological findings in four cases, whereas in the remaining two cases, the lesions were classed as type I or II on CT and as mixed (type I and II) lesions at histopathology. In one case, the CT classification was correct, but the histopathology revealed the coexistence of pulmonary sequestration. In our study, there was concordance between CT and histopathology in 66.7% of cases, whereas in 33.3% histopathology revealed areas with mixed grade lesions. CT proved to be accurate in identifying and characterising CAM and provided important information on lesion site and extension.

  6. Detection of pulmonary fat embolism with dual-energy CT: an experimental study in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chun Xiang; Zhou, Chang Sheng; Zhao, Yan E.; Han, Zong Hong; Qi, Li; Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Schoepf, U.J. [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Mangold, Stefanie; Ball, B.D. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States)

    2017-04-15

    To evaluate the use of dual-energy CT imaging of the lung perfused blood volume (PBV) for the detection of pulmonary fat embolism (PFE). Dual-energy CT was performed in 24 rabbits before and 1 hour, 1 day, 4 days and 7 days after artificial induction of PFE via the right ear vein. CT pulmonary angiography (CTPA) and lung PBV images were evaluated by two radiologists, who recorded the presence, number, and location of PFE on a per-lobe basis. Sensitivity, specificity, and accuracy of CTPA and lung PBV for detecting PFE were calculated using histopathological evaluation as the reference standard. A total of 144 lung lobes in 24 rabbits were evaluated and 70 fat emboli were detected on histopathological analysis. The overall sensitivity, specificity and accuracy were 25.4 %, 98.6 %, and 62.5 % for CTPA, and 82.6 %, 76.0 %, and 79.2 % for lung PBV. Higher sensitivity (p < 0.001) and accuracy (p < 0.01), but lower specificity (p < 0.001), were found for lung PBV compared with CTPA. Dual-energy CT can detect PFE earlier than CTPA (all p < 0.01). Dual-energy CT provided higher sensitivity and accuracy in the detection of PFE as well as earlier detection compared with conventional CTPA in this animal model study. (orig.)

  7. CT head in children

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Padma, E-mail: padma.rao@rch.org.au [Royal Children' s Hospital and the University of Melbourne, Medical Imaging Department, Flemington Road, Parkville, Melbourne, Victoria 3052 (Australia); Bekhit, Elhamy, E-mail: elhamy.bekhit@rch.org.au [Royal Children' s Hospital and the University of Melbourne, Medical Imaging Department, Flemington Road, Parkville, Melbourne, Victoria 3052 (Australia); Ramanauskas, Fiona, E-mail: fiona.ramanauskas@rch.org.au [Royal Children' s Hospital and the University of Melbourne, Medical Imaging Department, Flemington Road, Parkville, Melbourne, Victoria 3052 (Australia); Kumbla, Surekha, E-mail: surekha.kumbla@rch.org.au [Royal Children' s Hospital and the University of Melbourne, Medical Imaging Department, Flemington Road, Parkville, Melbourne, Victoria 3052 (Australia)

    2013-07-15

    The advances in computerized technology (CT) technique over the last few decades have greatly modified imaging protocols in children. The range of pathologies that can now be demonstrated has broadened with the advent of newer techniques such as CT perfusion and the ability to perform complex reconstructions. Increasing speed of scanning and reduction in scan time have influenced the need for sedation and general anaesthetic as well as impacting on motion artefact. Additionally, concerns about radiation safety and avoidance of unnecessary radiation have further impacted on the inclusion of CT in the imaging armamentarium. Justification and image optimisation are essential. It is important to familiarize oneself with the appearances of normal variants or age related developmental changes. CT does however remain an appropriate investigation in a number of conditions.

  8. Treatment planning using MRI data: an analysis of the dose calculation accuracy for different treatment regions

    Directory of Open Access Journals (Sweden)

    Karlsson Mikael

    2010-06-01

    Full Text Available Abstract Background Because of superior soft tissue contrast, the use of magnetic resonance imaging (MRI as a complement to computed tomography (CT in the target definition procedure for radiotherapy is increasing. To keep the workflow simple and cost effective and to reduce patient dose, it is natural to strive for a treatment planning procedure based entirely on MRI. In the present study, we investigate the dose calculation accuracy for different treatment regions when using bulk density assignments on MRI data and compare it to treatment planning that uses CT data. Methods MR and CT data were collected retrospectively for 40 patients with prostate, lung, head and neck, or brain cancers. Comparisons were made between calculations on CT data with and without inhomogeneity corrections and on MRI or CT data with bulk density assignments. The bulk densities were assigned using manual segmentation of tissue, bone, lung, and air cavities. Results The deviations between calculations on CT data with inhomogeneity correction and on bulk density assigned MR data were small. The maximum difference in the number of monitor units required to reach the prescribed dose was 1.6%. This result also includes effects of possible geometrical distortions. Conclusions The dose calculation accuracy at the investigated treatment sites is not significantly compromised when using MRI data when adequate bulk density assignments are made. With respect to treatment planning, MRI can replace CT in all steps of the treatment workflow, reducing the radiation exposure to the patient, removing any systematic registration errors that may occur when combining MR and CT, and decreasing time and cost for the extra CT investigation.

  9. Process Analysis Via Accuracy Control

    Science.gov (United States)

    1982-02-01

    0 1 4 3 NDARDS THE NATIONAL February 1982 Process Analysis Via Accuracy Control RESEARCH PROG RAM U.S. DEPARTMENT OF TRANSPORTATION Maritime...SUBTITLE Process Analysis Via Accuracy Control 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...examples are contained in Appendix C. Included, are examples of how “A/C” process - analysis leads to design improvement and how a change in sequence can

  10. Usefulness and limit of CT diagnosis on appendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Kuchiki, Megumi; Takanashi, Toshiyasu [Sakata Municipal Hospital, Yamagata (Japan); Yamaguchi, Koichi

    1997-08-01

    CT was performed in 104 patients with abdominal pain suspected appendicitis. CT showed positive finding (abnormal appendix, appendicolith, pericecal inflammatory change, fluid collection, LN swelling, abscess) and complication of appendicitis clearly. CT diagnosis showed high accuracy than clinical diagnosis. CT proved its usefulness especially only CT imaging showed the correct diagnosis. On the other hand, diverticulitis and terminal ileitis common diagnostic disease of appendicitis showed similar clinical appearance and CT image, caused to be difficult to diagnose correctly. In the cases showing similar image to appendicitis or atypical image, CT also proved its limit of the diagnosis on appendicitis. (author)

  11. Value of surveillance {sup 18}F FDG PET/CT in colorectal cancer:comparison with conventional imaging studies

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Eun Kyoung; Yoo, Ie Ryung; Park, Hye Lim; Choi, Hyun Su; Han, Eun Ji; Kim, Sung Hoon; Chung, Soo Kyo; O, Joo Hyun [The Catholic Univ. of Korea, Seoul (Korea, Republic of)

    2012-09-15

    To assess the value of PET/CT for detecting local or distant recurrence in patients who undergo surgery for colorectal cancer (CRC)and to compare the accuracy of PET/CT to that of conventional imaging studies (CIS). Tumor surveillance PET/CT scans done between March 2005 and December 2009 of disease free patients after surgery with or without adjuvant chemotherapy for CRC were retrospectively studied. CIS (serial enhanced CT from lung base to pelvis and plain chest radiograph)were performed within 1 month of PET/CT. We excluded patients with distant metastasis on initial staging, a known recurrent tumor, and a lack of follow up imaging. The final diagnosis was based on at least 6 months of follow up with colonoscopy, biopsy, and serial imaging studies in combination with carcinoembryonic antigen levels. A total of 262 PET/CT scans of 245 patients were included. Local and distant recurrences were detected in 27 cases (10.3%). On case based analysis, the overall sensitivity, specificity, and accuracy were 100, 97.0, and 97.3% for PET/CT and 85.1, 97.0, and 95.8% for CIS, respectively. On lesion based analysis, PET/CT detected more lesions compared to CIS in local recurrence and lung metastasis. PET/CT and CIS detected the same number of lesions in abdominal lymph nodes, hepatic metastasis, and peritoneal carcinomatosis. PET/CT detected two more metachronous tumors than did CIS in the lung and thyroid gland. PET/CT detected more recurrences in patients who underwent surgery for CRC than did CIS and had the additional advantage of evaluating the entire body during a single scan.

  12. USING OF MULTISLICE HELICAL CT COLONOGRAPHY IN PATIENTS WITH MALIGNANT LESIONS OF COLON

    Institute of Scientific and Technical Information of China (English)

    Ming-wei Qin; Wei-dong Pan; Guan-ning Cong; Yun Wang; Yun-qing Zhang; Wen-bin Mou; Zheng-yu Jin

    2005-01-01

    Objective To investigate the techniques and clinical applications of multislice helical computed tomography (CT) colono graphy in colonic lesions. Methods Fifty-nine patients with malignant lesions of colon underwent volume scanning using multislice helical CT. Four types of reconstruction including CT virtual colonoscopy (CTVC), shaded surface display (SSD), Raysum, and mu ltiple planar reconstruction (MPR) were used for image post-processing. The results were compared with those of colonos copy and pathology. Results Multislice helical CT colonography detected 54 colorectal carcinomas, 4 adenomas with focal carcinoma, 1 non-Hodgkin's lymphoma (NHL). The lesions' number, size, location, morphology, stricture of intestinal cavity, infiltration, and metastasis were shown satisfactorily by multislice helical CT colonography. Whole colon could be shown in all patients. CT colonography displayed 4 synchronous colonic tumors, 1 ascending colon carcinoma combined with left renal carcinoma among 54 patients with colonic carcinomas. The accuracy of location of CT colonography was 100%. There were 9 cases that CT showed the tumor location was different from the finding of conventional colonoscopy, while all of the CT location were proven exact by operation. CT colonography also displayed the infiltration of serous layer and fatty tissue in 45 cases; 21 cases matched the pathological results in all the 24 cases of suspicious lymph node metastasis, the sensitivity was 87.5%, the specificity was 90.6%; 9 cases hepatic metastasis, 2 ovarian metastasis, and 1 double adrenal gland metastasis.Conclusions Multislice helical CT colonography is effective in preoperative diagnosis, location, stage, and making treatment plan of colorectal carcinoma. It can display the portion not seen during colonoscopy and may have an adjunctive role.

  13. SU-E-I-13: Evaluation of Metal Artifact Reduction (MAR) Software On Computed Tomography (CT) Images

    Energy Technology Data Exchange (ETDEWEB)

    Huang, V; Kohli, K [BC Cancer Agency, Surrey, BC (United Kingdom)

    2015-06-15

    Purpose: A new commercially available metal artifact reduction (MAR) software in computed tomography (CT) imaging was evaluated with phantoms in the presence of metals. The goal was to assess the ability of the software to restore the CT number in the vicinity of the metals without impacting the image quality. Methods: A Catphan 504 was scanned with a GE Optima RT 580 CT scanner (GE Healthcare, Milwaukee, WI) and the images were reconstructed with and without the MAR software. Both datasets were analyzed with Image Owl QA software (Image Owl Inc, Greenwich, NY). CT number sensitometry, MTF, low contrast, uniformity, noise and spatial accuracy were compared for scans with and without MAR software. In addition, an in-house made phantom was scanned with and without a stainless steel insert at three different locations. The accuracy of the CT number and metal insert dimension were investigated as well. Results: Comparisons between scans with and without MAR algorithm on the Catphan phantom demonstrate similar results for image quality. However, noise was slightly higher for the MAR algorithm. Evaluation of the CT number at various locations of the in-house made phantom was also performed. The baseline HU, obtained from the scan without metal insert, was compared to scans with the stainless steel insert at 3 different locations. The HU difference between the baseline scan versus metal scan was improved when the MAR algorithm was applied. In addition, the physical diameter of the stainless steel rod was over-estimated by the MAR algorithm by 0.9 mm. Conclusion: This work indicates with the presence of metal in CT scans, the MAR algorithm is capable of providing a more accurate CT number without compromising the overall image quality. Future work will include the dosimetric impact on the MAR algorithm.

  14. Performance evaluation of the CT component of the IRIS PET/CT preclinical tomograph

    Energy Technology Data Exchange (ETDEWEB)

    Panetta, Daniele [CNR Institute of Clinical Physiology (IFC-CNR), v. G. Moruzzi 1, I-56124 Pisa (Italy); Belcari, Nicola [Department of Physics “E. Fermi”, University of Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy); Tripodi, Maria [CNR Institute of Clinical Physiology (IFC-CNR), v. G. Moruzzi 1, I-56124 Pisa (Italy); Burchielli, Silvia [Fondazione CNR/Toscana “G. Monasterio” – FTGM, v. G. Moruzzi 1, I-56124 Pisa (Italy); Salvadori, Piero A. [CNR Institute of Clinical Physiology (IFC-CNR), v. G. Moruzzi 1, I-56124 Pisa (Italy); Del Guerra, Alberto [Department of Physics “E. Fermi”, University of Pisa, L.go B. Pontecorvo 3, I-56127 Pisa (Italy)

    2016-01-01

    In this paper, we evaluate the physical performance of the CT component of the IRIS scanner, a novel combined PET/CT scanner for preclinical imaging. The performance assessment is based on phantom measurement for the determination of image quality parameters (spatial resolution, linearity, geometric accuracy, contrast to noise ratio) and reproducibility in dynamic (4D) imaging. The CTDI{sub 100} has been measured free in air with a pencil ionization chamber, and the animal dose was calculated using Monte Carlo derived conversion factors taken from the literature. The spatial resolution at the highest quality protocol was 6.9 lp/mm at 10% of the MTF, using the smallest reconstruction voxel size of 58.8 μm. The accuracy of the reconstruction voxel size was within 0.1%. The linearity of the CT numbers as a function of the concentration of iodine was very good, with R{sup 2}>0.996 for all the tube voltages. The animal dose depended strongly on the scanning protocol, ranging from 158 mGy for the highest quality protocol (2 min, 80 kV) to about 12 mGy for the fastest protocol (7.3 s, 80 kV). In 4D dynamic modality, the maximum scanning rate reached was 3.1 frames per minute, using a short-scan protocol with 7.3 s of scan time per frame at the isotropic voxel size of 235 μm. The reproducibility of the system was high throughout the 10 frames acquired in dynamic modality, with a standard deviation of the CT values of all frames <8 HU and an average spatial reproducibility within 30% of the voxel size across all the field of view. Example images obtained during animal experiments are also shown.

  15. Genomic selection and association mapping in rice (Oryza sativa): effect of trait genetic architecture, training population composition, marker number and statistical model on accuracy of rice genomic selection in elite, tropical rice breeding lines.

    Science.gov (United States)

    Spindel, Jennifer; Begum, Hasina; Akdemir, Deniz; Virk, Parminder; Collard, Bertrand; Redoña, Edilberto; Atlin, Gary; Jannink, Jean-Luc; McCouch, Susan R

    2015-02-01

    Genomic Selection (GS) is a new breeding method in which genome-wide markers are used to predict the breeding value of individuals in a breeding population. GS has been shown to improve breeding efficiency in dairy cattle and several crop plant species, and here we evaluate for the first time its efficacy for breeding inbred lines of rice. We performed a genome-wide association study (GWAS) in conjunction with five-fold GS cross-validation on a population of 363 elite breeding lines from the International Rice Research Institute's (IRRI) irrigated rice breeding program and herein report the GS results. The population was genotyped with 73,147 markers using genotyping-by-sequencing. The training population, statistical method used to build the GS model, number of markers, and trait were varied to determine their effect on prediction accuracy. For all three traits, genomic prediction models outperformed prediction based on pedigree records alone. Prediction accuracies ranged from 0.31 and 0.34 for grain yield and plant height to 0.63 for flowering time. Analyses using subsets of the full marker set suggest that using one marker every 0.2 cM is sufficient for genomic selection in this collection of rice breeding materials. RR-BLUP was the best performing statistical method for grain yield where no large effect QTL were detected by GWAS, while for flowering time, where a single very large effect QTL was detected, the non-GS multiple linear regression method outperformed GS models. For plant height, in which four mid-sized QTL were identified by GWAS, random forest produced the most consistently accurate GS models. Our results suggest that GS, informed by GWAS interpretations of genetic architecture and population structure, could become an effective tool for increasing the efficiency of rice breeding as the costs of genotyping continue to decline.

  16. Genomic selection and association mapping in rice (Oryza sativa: effect of trait genetic architecture, training population composition, marker number and statistical model on accuracy of rice genomic selection in elite, tropical rice breeding lines.

    Directory of Open Access Journals (Sweden)

    Jennifer Spindel

    2015-02-01

    Full Text Available Genomic Selection (GS is a new breeding method in which genome-wide markers are used to predict the breeding value of individuals in a breeding population. GS has been shown to improve breeding efficiency in dairy cattle and several crop plant species, and here we evaluate for the first time its efficacy for breeding inbred lines of rice. We performed a genome-wide association study (GWAS in conjunction with five-fold GS cross-validation on a population of 363 elite breeding lines from the International Rice Research Institute's (IRRI irrigated rice breeding program and herein report the GS results. The population was genotyped with 73,147 markers using genotyping-by-sequencing. The training population, statistical method used to build the GS model, number of markers, and trait were varied to determine their effect on prediction accuracy. For all three traits, genomic prediction models outperformed prediction based on pedigree records alone. Prediction accuracies ranged from 0.31 and 0.34 for grain yield and plant height to 0.63 for flowering time. Analyses using subsets of the full marker set suggest that using one marker every 0.2 cM is sufficient for genomic selection in this collection of rice breeding materials. RR-BLUP was the best performing statistical method for grain yield where no large effect QTL were detected by GWAS, while for flowering time, where a single very large effect QTL was detected, the non-GS multiple linear regression method outperformed GS models. For plant height, in which four mid-sized QTL were identified by GWAS, random forest produced the most consistently accurate GS models. Our results suggest that GS, informed by GWAS interpretations of genetic architecture and population structure, could become an effective tool for increasing the efficiency of rice breeding as the costs of genotyping continue to decline.

  17. Dosimetric impact of a CT metal artefact suppression algorithm for proton, electron and photon therapies.

    Science.gov (United States)

    Wei, Jikun; Sandison, George A; Hsi, Wen-Chien; Ringor, Michael; Lu, Xiaoyi

    2006-10-21

    Accurate dose calculation is essential to precision radiation treatment planning and this accuracy depends upon anatomic and tissue electron density information. Modern treatment planning inhomogeneity corrections use x-ray CT images and calibrated scales of tissue CT number to electron density to provide this information. The presence of metal in the volume scanned by an x-ray CT scanner causes metal induced image artefacts that influence CT numbers and thereby introduce errors in the radiation dose distribution calculated. This paper investigates the dosimetric improvement achieved by a previously proposed x-ray CT metal artefact suppression technique when the suppressed images of a patient with bilateral hip prostheses are used in commercial treatment planning systems for proton, electron or photon therapies. For all these beam types, this clinical image and treatment planning study reveals that the target may be severely underdosed if a metal artefact-contaminated image is used for dose calculations instead of the artefact suppressed one. Of the three beam types studied, the metal artefact suppression is most important for proton therapy dose calculations, intermediate for electron therapy and least important for x-ray therapy but still significant. The study of a water phantom having a metal rod simulating a hip prosthesis indicates that CT numbers generated after image processing for metal artefact suppression are accurate and thus dose calculations based on the metal artefact suppressed images will be of high fidelity.

  18. Verification of a CT scanner using a miniature step gauge

    DEFF Research Database (Denmark)

    Cantatore, Angela; Andreasen, J.L.; Carmignato, S.;

    2011-01-01

    The work deals with performance verification of a CT scanner using a 42mm miniature replica step gauge developed for optical scanner verification. Errors quantification and optimization of CT system set-up in terms of resolution and measurement accuracy are fundamental for use of CT scanning...

  19. Applying a deep learning based CAD scheme to segment and quantify visceral and subcutaneous fat areas from CT images

    Science.gov (United States)

    Wang, Yunzhi; Qiu, Yuchen; Thai, Theresa; Moore, Kathleen; Liu, Hong; Zheng, Bin

    2017-03-01

    Abdominal obesity is strongly associated with a number of diseases and accurately assessment of subtypes of adipose tissue volume plays a significant role in predicting disease risk, diagnosis and prognosis. The objective of this study is to develop and evaluate a new computer-aided detection (CAD) scheme based on deep learning models to automatically segment subcutaneous fat areas (SFA) and visceral (VFA) fat areas depicting on CT images. A dataset involving CT images from 40 patients were retrospectively collected and equally divided into two independent groups (i.e. training and testing group). The new CAD scheme consisted of two sequential convolutional neural networks (CNNs) namely, Selection-CNN and Segmentation-CNN. Selection-CNN was trained using 2,240 CT slices to automatically select CT slices belonging to abdomen areas and SegmentationCNN was trained using 84,000 fat-pixel patches to classify fat-pixels as belonging to SFA or VFA. Then, data from the testing group was used to evaluate the performance of the optimized CAD scheme. Comparing to manually labelled results, the classification accuracy of CT slices selection generated by Selection-CNN yielded 95.8%, while the accuracy of fat pixel segmentation using Segmentation-CNN yielded 96.8%. Therefore, this study demonstrated the feasibility of using deep learning based CAD scheme to recognize human abdominal section from CT scans and segment SFA and VFA from CT slices with high agreement compared with subjective segmentation results.

  20. CT Enterography

    Science.gov (United States)

    ... You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras ... kind, unlike MRI. No radiation remains in a patient's body after a CT ... side effects. Risks There is always a slight chance of cancer ...

  1. {sup 68}Ga-DOTA-NOC PET/CT in comparison with CT for the detection of bone metastasis in patients with neuroendocrine tumours

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosini, Valentina; Nanni, Cristina; Castellucci, Paolo; Allegri, Vincenzo; Montini, Giancarlo; Franchi, Roberto [S. Orsola-Malpighi University Hospital, Department of Nuclear Medicine, Bologna (Italy); Zompatori, Maurizio [S. Orsola-Malpighi University Hospital, Department of Radiology, Bologna (Italy); Campana, Davide; Tomassetti, Paola [S. Orsola-Malpighi University Hospital, Department of Internal Medicine, Bologna (Italy); Rubello, Domenico [S. Maria della Misericordia Hospital, Department of Nuclear Medicine, Rovigo (Italy); Fanti, Stefano [S. Orsola-Malpighi University Hospital, Department of Nuclear Medicine, Bologna (Italy); Azienda Ospedaliero Universitaria di Bologna, Unita Operativa di Medicina Nucleare, Padiglione 30, Policlinico S.Orsola-Malpighi, Bologna (Italy)

    2010-04-15

    To retrospectively evaluate the sensitivity, specificity and accuracy of {sup 68}Ga-DOTA-NOC PET/CT and CT alone for the evaluation of bone metastasis in patients with neuroendocrine tumour (NET). From among patients with NET who underwent {sup 68}Ga-DOTA-NOC PET/CT between April 2006 and November 2008 in our centre, 223 were included in the study. Criteria for inclusion were pathological confirmation of NET and a follow-up period of at least 10 months. PET and CT images were retrospectively reviewed by two nuclear medicine specialists and two radiologists, respectively, without knowledge of the patient history or the findings of other imaging modalities. PET data were compared with the CT findings. Interobserver agreement was evaluated in terms of the kappa score. Clinical and imaging follow-up were used as the standard of reference to evaluate the PET findings. PET was performed for staging (49/223), unknown primary tumour detection (24/223), restaging (32/223), restaging before radioimmunotherapy (1/223), evaluation during therapy (12/223), equivocal findings on conventional imaging (4/223 at the bone level; 61/223 at sites other than bone), and follow-up (40/223). A very high interobserver agreement was observed. CT detected at least one bone lesion in only 35 of 44 patients with a positive PET scan. In particular, PET showed more lesions in 20/35 patients, a lower number of lesions in 8/35, and the same number in 7/35. The characteristics of the lesions (sclerotic, lytic, mixed) on the basis of the CT report did not influence PET reading. PET revealed the presence of at least one bone metastasis in nine patients with a negative CT scan. Considering patients with a negative PET scan (179), CT showed equivocal findings at the bone level in three (single small sclerotic abnormality in two at the spine level, and bilateral small sclerotic abnormalities in the humeri, femurs and scapula). Clinical follow-up confirmed the PET findings in all patients; thus there

  2. Improved attenuation correction for respiratory gated PET/CT with extended-duration cine CT: a simulation study

    Science.gov (United States)

    Zhang, Ruoqiao; Alessio, Adam M.; Pierce, Larry A.; Byrd, Darrin W.; Lee, Tzu-Cheng; De Man, Bruno; Kinahan, Paul E.

    2017-03-01

    Due to the wide variability of intra-patient respiratory motion patterns, traditional short-duration cine CT used in respiratory gated PET/CT may be insufficient to match the PET scan data, resulting in suboptimal attenuation correction that eventually compromises the PET quantitative accuracy. Thus, extending the duration of cine CT can be beneficial to address this data mismatch issue. In this work, we propose to use a long-duration cine CT for respiratory gated PET/CT, whose cine acquisition time is ten times longer than a traditional short-duration cine CT. We compare the proposed long-duration cine CT with the traditional short-duration cine CT through numerous phantom simulations with 11 respiratory traces measured during patient PET/CT scans. Experimental results show that, the long-duration cine CT reduces the motion mismatch between PET and CT by 41% and improves the overall reconstruction accuracy by 42% on average, as compared to the traditional short-duration cine CT. The long-duration cine CT also reduces artifacts in PET images caused by misalignment and mismatch between adjacent slices in phase-gated CT images. The improvement in motion matching between PET and CT by extending the cine duration depends on the patient, with potentially greater benefits for patients with irregular breathing patterns or larger diaphragm movements.

  3. Accuracy, image quality and radiation dose comparison of high-pitch spiral and sequential acquisition on 128-slice dual-source CT angiography in children with congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Pei; Wang, Ximing; Cheng, Zhaoping; Ji, Xiaopeng; Duan, Yanhua [Shandong University, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Chen, Jiuhong [CT Research Collaboration, Siemens Ltd. China, Beijing (China)

    2012-10-15

    To compare accuracy, image quality and radiation dose between high-pitch spiral and sequential modes on 128-slice dual-source computed tomographic (DSCT) angiography in children with congenital heart disease (CHD). Forty patients suspected with CHD underwent 128-slice DSCT angiography with high-pitch mode and sequential mode respectively. All the anomalies were confirmed by the surgical and/or the conventional cardiac angiography (CCA) findings. The diagnostic accuracy, the subjective and objective image quality and effective radiation doses were compared. There was no significant difference in diagnostic accuracy ({chi}{sup 2} = 0.963, P > 0.05), the objective parameters for image quality (P > 0.05) and the image quality of great vessels (u = 167.500, P > 0.05) between the two groups. The image quality of intracardiac structures and coronary arteries was significantly better in the sequential mode group than that in the high-pitch group (u = 112.500 and 100.000, P < 0.05). The mean effective dose in high-pitch group (0.17 {+-} 0.05 mSv) was significantly lower (t = 5.287, P < 0.05) than that in the sequential mode group (0.29 {+-} 0.09 mSv). Both the high-pitch and the sequential modes for 128-slice DSCT angiography provide high accuracy for the assessment of CHD in children, while the high-pitch mode, even with some image quality decrease, further significantly lowers the radiation dose. (orig.)

  4. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... a stroke, especially with a new technique called Perfusion CT. brain tumors. enlarged brain cavities (ventricles) in ... X-Ray and CT Exams Blood Clots CT Perfusion of the Head CT Angiography (CTA) Stroke Brain ...

  5. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special ... the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT ...

  6. A prospective study comparing (99m)Tc-HDP planar bone scintigraphy and whole-body SPECT/CT with (18)F-fluoride PET/CT and (18)F-fluoride PET/MRI for diagnosing bone metastases.

    Science.gov (United States)

    Löfgren, Johan; Mortensen, Jann; Rasmussen, Sine Hvid; Madsen, Claus; Loft, Annika; Hansen, Adam Espe; Oturai, Peter; Jensen, Karl Erik; Mørk, Mette Louise; Reichkendler, Michala; Højgaard, Liselotte; Fischer, Barbara M

    2017-08-10

    We prospectively evaluate and compare the diagnostic performance of (99m)Tc-HDP planar bone scintigraphy (pBS), (99m)Tc-HDP SPECT/CT, (18)F-NaF PET/CT and (18)F-NaF PET/MRI for the detection of bone metastases. Methods: 117 patients with histologically proven malignancy referred for clinical pBS were prospectively enrolled. pBS and whole-body SPECT/CT were performed followed by (18)F-NaF PET/CT within 9 days. (18)F-NaF PET/MRI was also performed in 46 patients. A "truth panel" including clinical follow-up served as standard of reference. Results: Bone metastases were confirmed in 16 patients and excluded in 101. When equivocal readings were excluded no statistically significant difference in sensitivity, specificity, PPV, NPV or overall accuracy were found when comparing the different imaging techniques. With a pessimistic analysis, interpreting equivocal scans as positive, (18)F-NaF-PET showed a significant higher specificity and accuracy than pBS (93.1% vs 81.2%, P = 0.012 and 91.5% vs. 79.5%, P = 0.011). With an optimistic analysis, interpreting equivocal scans as negative, (18)F-NaF-PET showed significant higher accuracy than SPECT/CT (94.9% vs. 88.0%, P = 0.039) but not compared to pBS. The number of equivocal scans were significantly higher for pBS than for SPECT/CT and PET/CT (18 vs 5 and 6 respectively, P = 0.004 resp. P = 0.01). Conclusion:(18)F-NaF PET/CT and whole body SPECT/CT resulted in a significant reduction of equivocal readings compared to pBS which implies an improved diagnostic confidence. However, this large prospective study could not verify prior published results on (18)F-NaF-PET/CT superior overall accuracy compared to neither pBS nor whole-body SPECT/CT. The subgroup analysis of 46 patients with (18)F-NaF-PET/MRI failed to demonstrate significantly improved overall diagnostic accuracy. Copyright © 2017 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  7. Low tube voltage and low contrast material volume cerebral CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Song [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Xuzhou Medical College, School of Medical Imaging, Xuzhou, Jiangsu (China); Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Meinel, Felix G.; McQuiston, Andrew D. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Zhou, Chang Sheng; Qi, Li [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Schoepf, U.J. [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States)

    2014-07-15

    To evaluate the image quality, radiation dose and diagnostic accuracy of low kVp and low contrast material volume cerebral CT angiography (CTA) in intracranial aneurysm detection. One hundred twenty patients were randomly divided into three groups (n = 40 for each): Group A, 70 ml iodinated contrast agent/120 kVp; group B, 30 ml/100 kVp; group C, 30 ml/80 kVp. The CT numbers, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured in the internal carotid artery (ICA) and middle cerebral artery (MCA). Subjective image quality was evaluated. For patients undergoing DSA, diagnostic accuracy of CTA was calculated with DSA as reference standard and compared. CT numbers of ICA and MCA were higher in groups B and C than in group A (P < 0.01). SNR and CNR in groups A and B were higher than in group C (both P < 0.05). There was no difference in subjective image quality among the three groups (P = 0.939). Diagnostic accuracy for aneurysm detection among these groups had no statistical difference (P = 1.00). Compared with group A, the radiation dose of groups B and C was decreased by 45 % and 74 %. Cerebral CTA at 100 or 80 kVp using 30 ml contrast agent can obtain diagnostic image quality with a low radiation dose while maintaining the same diagnostic accuracy for aneurysm detection. (orig.)

  8. CT-guided core needle biopsy of pleural lesions: Evaluating diagnostic yield and associated complications

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Xiang Ke [Dept. of Radiology, Affiliated Hospital of Chengdu University, Chengdu (China); Bhetuwal, Anup; Yang, Han Feng [Dept. of Radiology, Sichuan Key Laboratory of Medical Imaging, Affiliated Hospital of North Sichuan Medical College, Nanchong (China)

    2015-02-15

    The purpose of this study was to retrospectively evaluate the diagnostic accuracy and complications of CT-guided core needle biopsy (CT-guided CNB) of pleural lesion and the possible effects of influencing factors. From September 2007 to June 2013, 88 consecutive patients (60 men and 28 women; mean [+/- standard deviation] age, 51.1 +/- 14.4 years; range, 19-78 years) underwent CT-guided CNB, which was performed by two experienced chest radiologists in our medical center. Out of 88 cases, 56 (63%) were diagnosed as malignant, 28 (31%) as benign and 4 (5%) as indeterminate for CNB of pleural lesions. The final diagnosis was confirmed by either histopathological diagnosis or clinical follow-up. The diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and complication rates were statistically evaluated. Influencing factors (patient age, sex, lesion size, pleural-puncture angle, patient position, pleural effusion, and number of pleural punctures) were assessed for their effect on accuracy of CT-guided CNB using univariate and subsequent multivariate analysis. Diagnostic accuracy, sensitivity, specificity, PPV, and NPV were 89.2%, 86.1%, 100%, 100%, and 67.8%, respectively. The influencing factors had no significant effect in altering diagnostic accuracy. As far as complications were concerned, occurrence of pneumothorax was observed in 14 (16%) out of 88 patients. Multivariate analysis revealed lesion size/pleural thickening as a significant risk factor (odds ratio [OR]: 8.744, p = 0.005) for occurrence of pneumothorax. Moreover, presence of pleural effusion was noted as a significant protective factor (OR: 0.171, p = 0.037) for pneumothorax. CT-guided CNB of pleural lesion is a safe procedure with high diagnostic yield and low risk of significant complications.

  9. Abdominal aspergillosis: CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, Suk Keu, E-mail: pagoda20@hanmail.net [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Kim, Hye Jin, E-mail: kimhyejin@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Byun, Jae Ho, E-mail: jhbyun@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Kim, Ah Young, E-mail: aykim@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Lee, Moon-Gyu, E-mail: mglee@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of); Ha, Hyun Kwon, E-mail: hkha@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap2-dong, Songpa-gu, Seoul, 138-736 (Korea, Republic of)

    2011-03-15

    Objective: In order to retrospectively evaluate the CT findings of abdominal aspergillosis in immunocompromised patients. Materials and methods: CT scans were reviewed with regard to the sites, number, morphologic appearance, attenuation, and the contrast enhancement patterns of the lesions in six patients (5 women, 1 man; mean age, 43.4 years; range, 23-59 years) with pathologically proved abdominal aspergillosis by two gastrointestinal radiologists in consensus. Medical records were also reviewed to determine each patient's clinical status and outcome. Results: All patients were immunocompromised state: 4 patients received immunosuppressive therapy for solid organ transplantation and 2 patients received chemotherapy for acute myeloid leukemia. Aspergillosis involved blood vessels (n = 3), liver (n = 2), spleen (n = 2), gastrointestinal tract (n = 2), native kidney (n = 1), transplanted kidney (n = 1), peritoneum (n = 1), and retroperitoneum (n = 1). CT demonstrated solid organ or bowel infarction or perforation secondary to vascular thrombosis or pseudoaneurysm, multiple low-attenuating lesions of solid organs presenting as abscesses, concentric bowel wall thickening mimicking typhlitis, or diffuse or nodular infiltration of the peritoneum and retroperitoneum. Conclusion: Familiarity with findings commonly presenting as angioinvasive features or abscesses on CT, may facilitate the diagnosis of rare and fatal abdominal aspergillosis.

  10. Accuracy of marker analysis, quantitative real-time polymerase chain reaction, and multiple ligation-dependent probe amplification to determine SMN2 copy number in patients with spinal muscular atrophy.

    Science.gov (United States)

    Alías, Laura; Bernal, Sara; Barceló, Maria J; Also-Rallo, Eva; Martínez-Hernández, Rebeca; Rodríguez-Alvarez, Francisco J; Hernández-Chico, Concepción; Baiget, Montserrat; Tizzano, Eduardo F

    2011-09-01

    Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by absence of or mutations in the survival motor neuron1 gene (SMN1). All SMA patients have a highly homologous copy of SMN1, the SMN2 gene. Severe (type I) SMA patients present one or two SMN2 copies, whereas milder chronic forms (type II-III) usually have three or four SMN2 copies. SMN2 dosage is important to stratify patients for motor function tests and clinical trials. Our aim was to compare three methods, marker analysis, real-time quantitative polymerase chain reaction using the LightCycler instrument, and multiple ligation-dependent probe amplification (MLPA), to characterize their accuracy in quantifying SMN2 genes. We studied a group of 62 genetically confirmed SMA patients, 54 with homozygous absence of exons 7 and 8 of SMN1 and 8 with SMN2-SMN1 hybrid genes. A complete correlation using the three methods was observed in 32 patients (51.6%). In the remaining 30 patients, discordances between the three methods were found, including under or overestimation of SMN2 copies by marker analysis with respect to the quantitative methods (LightCycler and MLPA) because of lack of informativeness of markers, 3' deletions of SMN genes, and breakpoints in SMN2-SMN1 hybrid genes. The technical limitations and advantages and disadvantages of these methods are discussed. We conclude that the three methods complement each other in estimating the SMN2 copy number in most cases. However, MLPA offers additional information to characterize SMA cases with particular rearrangements such as partial deletions and hybrid genes.

  11. Automated segmentation of mammary gland regions in non-contrast torso CT images based on probabilistic atlas

    Science.gov (United States)

    Zhou, X.; Kan, M.; Hara, T.; Fujita, H.; Sugisaki, K.; Yokoyama, R.; Lee, G.; Hoshi, H.

    2007-03-01

    The identification of mammary gland regions is a necessary processing step during the anatomical structure recognition of human body and can be expected to provide the useful information for breast tumor diagnosis. This paper proposes a fully-automated scheme for segmenting the mammary gland regions in non-contrast torso CT images. This scheme calculates the probability for each voxel belonging to the mammary gland or other regions (for example pectoralis major muscles) in CT images and decides the mammary gland regions automatically. The probability is estimated from the location of the mammary gland and pectoralis major muscles in CT images. The location (named as a probabilistic atlas) is investigated from the pre-segmentation results in a number of different CT scans and the CT number distribution is approximated using a Gaussian function. We applied this scheme to 66 patient cases (female, age: 40-80) and evaluated the accuracy by using the coincidence rate between the segmented result and gold standard that is generated manually by a radiologist for each CT case. The mean value of the coincidence rate was 0.82 with the standard deviation of 0.09 for 66 CT cases.

  12. Clinical applications of SPECT-CT

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadzadehfar, Hojjat; Biersack, Hans-Juergen (eds.) [University Hospital Bonn (Germany). Dept. of Nuclear Medicine

    2014-06-01

    Covers the full spectrum of clinical applications of SPECT/CT in diagnosis of benign and malignant diseases. Includes chapters on the use of SPECT/CT for dosimetry and for therapy planning. Completely up to date. Many helpful illustrations. SPECT/CT cameras have considerably improved diagnostic accuracy in recent years. Such cameras allow direct correlation of anatomic and functional information, resulting in better localization and definition of scintigraphic findings. In addition to this anatomic referencing, CT coregistration provides superior quantification of radiotracer uptake based on the attenuation correction capabilities of CT. Useful applications of SPECT/CT have been identified not only in oncology but also in other specialties such as orthopedics and cardiology. This book covers the full spectrum of clinical applications of SPECT/CT in diagnosis and therapy planning of benign and malignant diseases. Opening chapters discuss the technology and physics of SPECT/CT and its use for dosimetry. The role of SPECT/CT in the imaging of a range of pathologic conditions is then addressed in detail. Applications covered include, among others, imaging of the thyroid, bone, and lungs, imaging of neuroendocrine tumors, cardiac scintigraphy, and sentinel node scintigraphy. Individual chapters are also devoted to therapy planning in selective internal radiation therapy of liver tumors and bremsstrahlung SPECT/CT. Readers will find this book to be an essential and up-to-date source of information on this invaluable hybrid imaging technique.

  13. The Value of Calcium-scoring CT for Ischemic Cardiovascular Disease Screening

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jung Hoan; An, Sung Min [Dept. of Radiological Science, Gachon University Science and Health, Incheon (Korea, Republic of)

    2009-03-15

    The cardiovascular disease has been known as a common cause of death for a long time in the west. The eating habits of Asia, including Korea, have changed recently, so that this disease is also a problem in Asia now. Annual Report on the Cause of Death Statistics from 1996 to 2006 reported that the cardiovascular disease would become the number one cause of death in the next years. Therefore we realize that more accurate examination is required. The aim of this study was to investigate the accuracy of Calcium-scoring CT and the relationship between risk factor and quantitative scores of Calcium-scoring CT. Through this study we expect that the national public health will be improved. Seventy patients with chest pain were chosen at random. The patients were undergone both coronary CT antigraphy and Calcium - scoring CT at G hospital in Incheon from February 1 to June 30, 2008. The result of the Calcium-scoring CT showed its usefulness for Ischemic cardiovascular disease, with an accuracy similar to that of exercise/pharmacologic stress or ECG when it is difficult for a patient to exercise due to joint problems, aging or for other reasons.

  14. Detection of pulmonary fat embolism with dual-energy CT: an experimental study in rabbits.

    Science.gov (United States)

    Tang, Chun Xiang; Zhou, Chang Sheng; Zhao, Yan E; Schoepf, U Joseph; Mangold, Stefanie; Ball, B Devon; Han, Zong Hong; Qi, Li; Zhang, Long Jiang; Lu, Guang Ming

    2017-04-01

    To evaluate the use of dual-energy CT imaging of the lung perfused blood volume (PBV) for the detection of pulmonary fat embolism (PFE). Dual-energy CT was performed in 24 rabbits before and 1 hour, 1 day, 4 days and 7 days after artificial induction of PFE via the right ear vein. CT pulmonary angiography (CTPA) and lung PBV images were evaluated by two radiologists, who recorded the presence, number, and location of PFE on a per-lobe basis. Sensitivity, specificity, and accuracy of CTPA and lung PBV for detecting PFE were calculated using histopathological evaluation as the reference standard. A total of 144 lung lobes in 24 rabbits were evaluated and 70 fat emboli were detected on histopathological analysis. The overall sensitivity, specificity and accuracy were 25.4 %, 98.6 %, and 62.5 % for CTPA, and 82.6 %, 76.0 %, and 79.2 % for lung PBV. Higher sensitivity (p PFE earlier than CTPA (all p PFE as well as earlier detection compared with conventional CTPA in this animal model study. • Fat embolism occurs commonly in patients with traumatic bone injury. • Dual-energy CT improves diagnostic performance for pulmonary fat embolism detection. • Dual-energy CT can detect pulmonary fat embolism earlier than CTPA.

  15. Diagnostic Accuracy of 256-Slice CT for Detecting Isolated Superior Mesenteric Artery Lesions%256层CT对孤立性肠系膜上动脉病变的诊断价值

    Institute of Scientific and Technical Information of China (English)

    叶自青; 王珏; 范占明; 刘英峰

    2016-01-01

    目的:探讨孤立性肠系膜上动脉病变(isolated superior mesenteric artery lesions,ISMAL)的256层CT的影像特征。方法回顾性分析12例ISMAL患者的影像及临床资料,以平扫横轴位、增强扫描横轴位、容积再现(VR)、曲面重建(CPR)、最大密度投影(MIP)等重建方法对肠系膜上动脉病变进行分析观察,总结其影像学特征。结果 ISMAL患者平均年龄为(50.1±2.7)岁,男性9例占75%,女性3例占25%,男性发生率高于女性。肠系膜上动脉栓塞(superior mesenteric artery embolism, SMAE)共8例,其中男性5例,女性3例;肠系膜上动脉夹层(superior mesenteric artery dissection, SMAD)共4例,均为男性;管腔局部增宽、腔内充盈缺损是SMAE典型征象;腔内条形低密度影并双腔的显示是SMAD的典型表现。结论256层CT平扫及CTA图像后处理技术可清晰显示肠系膜上动脉病变,确定其病变性质,了解其累及范围,为临床诊治提供有力的影像学依据。%Objective To evaluate the image features of isolated superior mesenteric artery lesion (ISMAL) by using 256 slice CT.Methods The images and clinical data of 12 patients were analyzed retrospectively. Every case was analyzed by the methods of vascular reconstruction, such as plain scan transverse axial, enhanced scan transverse axis, the volume rendering (VR), curved planar reformation (CPR), maximum intensity projection (MIP), and summarize the imaging characterization.Results The average age of ISMAL patients was (50.1±2.7)years old, 9 male (75%), 3 female (25%), the prevalence's of SMAD are higher among men than women. 8 patients were superior mesenteric artery embolism (SAME) including5 male and 3 female. 4 patients were superior mesenteric artery dissection (SMAD), all of them were male. The appearance of SMAE were filling defect in arteries and luminal local broadening. The typical manifestation of SMAD was the double chamber display of the strip and

  16. Optical-CT imaging of complex 3D dose distributions

    Science.gov (United States)

    Oldham, Mark; Kim, Leonard; Hugo, Geoffrey

    2005-04-01

    The limitations of conventional dosimeters restrict the comprehensiveness of verification that can be performed for advanced radiation treatments presenting an immediate and substantial problem for clinics attempting to implement these techniques. In essence, the rapid advances in the technology of radiation delivery have not been paralleled by corresponding advances in the ability to verify these treatments. Optical-CT gel-dosimetry is a relatively new technique with potential to address this imbalance by providing high resolution 3D dose maps in polymer and radiochromic gel dosimeters. We have constructed a 1st generation optical-CT scanner capable of high resolution 3D dosimetry and applied it to a number of simple and increasingly complex dose distributions including intensity-modulated-radiation-therapy (IMRT). Prior to application to IMRT, the robustness of optical-CT gel dosimetry was investigated on geometry and variable attenuation phantoms. Physical techniques and image processing methods were developed to minimize deleterious effects of refraction, reflection, and scattered laser light. Here we present results of investigations into achieving accurate high-resolution 3D dosimetry with optical-CT, and show clinical examples of 3D IMRT dosimetry verification. In conclusion, optical-CT gel dosimetry can provide high resolution 3D dose maps that greatly facilitate comprehensive verification of complex 3D radiation treatments. Good agreement was observed at high dose levels (>50%) between planned and measured dose distributions. Some systematic discrepancies were observed however (rms discrepancy 3% at high dose levels) indicating further work is required to eliminate confounding factors presently compromising the accuracy of optical-CT 3D gel-dosimetry.

  17. Improved detection of bone metastases from lung cancer in the thoracic cage using 5- and 1-mm axial images versus a new CT software generating rib unfolding images: comparison with standard ¹⁸F-FDG-PET/CT.

    Science.gov (United States)

    Homann, Georg; Mustafa, Deedar F; Ditt, Hendrik; Spengler, Werner; Kopp, Hans-Georg; Nikolaou, Konstantin; Horger, Marius

    2015-04-01

    To evaluate the performance of a dedicated computed tomography (CT) software called "bone reading" generating rib unfolded images for improved detection of rib metastases in patients with lung cancer in comparison to readings of 5- and 1-mm axial CT images and (18)F-Fluordeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT). Ninety consecutive patients who underwent (18)F-FDG-PET/CT and chest CT scanning between 2012 and 2014 at our institution were analyzed retrospectively. Chest CT scans with 5- and 1-mm slice thickness were interpreted blindly and separately focused on the detection of rib metastases (location, number, cortical vs. medullary, and osteoblastic vs. sclerotic). Subsequent image analysis of unfolded 1 mm-based CT rib images was performed. For all three data sets the reading time was registered. Finally, results were compared to those of FDG-PET. Validation was based on FDG-PET positivity for osteolytic and mixed osteolytic/osteoblastic focal rib lesions and follow-up for sclerotic PET-negative lesions. A total of 47 metastatic rib lesions were found on FDG-PET/CT plus another 30 detected by CT bone reading and confirmed by follow-up CT. Twenty-nine lesions were osteolytic, 14 were mixed osteolytic/osteoblastic, and 34 were sclerotic. On a patient-based analysis, CT (5 mm), CT (1 mm), and CT (1-mm bone reading) yielded a sensitivity, specificity, and accuracy of 76.5/97.3/93, 81.3/97.3/94, and 88.2/95.9/92, respectively. On segment-based (unfolded rib) analysis, the sensitivity, specificity, and accuracy of the three evaluations were 47.7/95.7/67, 59.5/95.8/77, and 94.8/88.2/92, respectively. Reading time for 5 mm/1 mm axial images and unfolded images was 40.5/50.7/21.56 seconds, respectively. The use of unfolded rib images in patients with lung cancer improves sensitivity and specificity of rib metastasis detection in comparison to 5- and 1-mm CT slice reading. Moreover, it may reduce the reading time. Copyright © 2015 AUR

  18. Observation on the Accuracy of Perfusion Imaging and CT Enhanced Scan in Determining Preoperative Grading of Gliomas%灌注成像与CT增强扫描对脑胶质瘤术前分级的判断准确性观察

    Institute of Scientific and Technical Information of China (English)

    杨磊; 杨元山; 张海燕

    2016-01-01

    目的:观察并分析灌注成像与CT增强扫描对脑胶质瘤术前分级的判断准确性。方法对2009年1月至2012年12月来我院就诊并治疗的76例脑胶质瘤患者作回顾性分析,进行灌注扫描与CT增强扫描,以两种诊断方法的影像学资料为基础,灌注成像参考脑血容量(CBV)、脑血流量(CBF)和脑血管表面通透性(PS)和相对脑血容量(rCBV)值进行术前分级, CT增强扫描以影像学图片为判断依据,对比术后病理结果,比较两组术前分级准确率。结果以术后病理结果为标准,灌注成像中,两级别组病灶区域的CBF、PS、CBV、rCBV值均大于对侧正常区域的对应值(P<0.05),高级别组各灌注参数显著大于低级别组对应值(P<0.05)。灌注成像在低级别组、高级别组的判断准确率分别为90.24%、91.43%,均显著高于CT增强扫描的准确率73.17%、71.43%(P<0.05)。结论灌注成像对脑胶质瘤术前分级准确性均高于CT增强扫描,是一种有效的胶质瘤术前诊断技术。%Objective To observe and analyze the accuracy of perfusion imaging and CT scan in determining preoperative grading of gliomas.Methods 76 cases of patients with gliomas who were treated in our hospital between January 2009 and December 2012 were retrospectively analyzed. All underwent perfusion scan and CT enhanced scan. Based on the imaging data of the two kinds of diagnostic methods, preoperative grading of perfusion imaging was performed with reference to cerebral blood volume (CBV), cerebral blood flow (CBF), cerebrovascular permeability surface (PS) and relative cerebral blood volume (rCBV) values.Results The postoperative pathological results were taken as the standard. In terms of perfusion imaging, the values of CBF, PS, CBV and rCBV of lesion areas in the two different grade of groups were greater than the corresponding values of the contralateral normal areas (P<0.05). The perfusion parameters of high grade

  19. The relationship between post-traumatic ossicular injuries and conductive hearing loss: A 3D-CT study.

    Science.gov (United States)

    Maillot, Olivier; Attyé, Arnaud; Boutet, Claire; Boubagra, Kamel; Perolat, Romain; Zanolla, Marion; Grand, Sylvie; Schmerber, Sébastien; Krainik, Alexandre

    2017-09-01

    After a trauma, the conductive ossicular chain may be disrupted by ossicular luxation or fracture. Recent developments in 3D-CT allow a better understanding of ossicular injuries. In this retrospective study, we compared patients with post-traumatic conductive hearing loss (CHL) with those referred without CHL to evaluate the relationship between ossicular injuries and CHL. We also assessed the added value of 3D reconstructions on 2D-CT scan to detect ossicular lesions in patients surgically managed. The CT scans were performed using a 40-section spiral CT scanner in 49 patients with post-traumatic CHL (n=29) and without CHL (n=20). Three radiologists performed independent blind evaluations of 2D-CT and 3D reconstructions to detect ossicular chain injury. We used the t-test to explore differences regarding the number of subjects with ossicular injury in the two groups. We also estimated the diagnostic accuracy and the inter-rater agreement of the 3D-CT reconstructions associated to 2D-CT scan. We identified ossicular abnormality in 14 patients out of 29 and in one patient out of 20 in the CHL and non-CHL groups respectively. There was a significant difference regarding the number of subjects with ossicular lesions between the two groups (P≤0.01). The diagnostic sensitivity of 3D-CT reconstructions associated with 2D-CT ranged from 66% to 100% and the inter-reader agreement ranged from 0.85 to 1, depending of the type of lesion. The relationship between ossicular lesion and the presence of CHL tightly correlated. 3D-CT reconstructions of the temporal bone are useful to assess patients in a post-traumatic context. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. SU-E-I-20: Comprehensive Quality Assurance Test of Second Generation Toshiba Aquilion Large Bore CT Simulator Based On AAPM TG-66 Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D [Toshiba America Medical Systems, Tustin, CA (United States)

    2015-06-15

    Purpose: AAPM radiation therapy committee task group No. 66 (TG-66) published a report which described a general approach to CT simulator QA. The report outlines the testing procedures and specifications for the evaluation of patient dose, radiation safety, electromechanical components, and image quality for a CT simulator. The purpose of this study is to thoroughly evaluate the performance of a second generation Toshiba Aquilion Large Bore CT simulator with 90 cm bore size (Toshiba, Nasu, JP) based on the TG-66 criteria. The testing procedures and results from this study provide baselines for a routine QA program. Methods: Different measurements and analysis were performed including CTDIvol measurements, alignment and orientation of gantry lasers, orientation of the tabletop with respect to the imaging plane, table movement and indexing accuracy, Scanogram location accuracy, high contrast spatial resolution, low contrast resolution, field uniformity, CT number accuracy, mA linearity and mA reproducibility using a number of different phantoms and measuring devices, such as CTDI phantom, ACR image quality phantom, TG-66 laser QA phantom, pencil ion chamber (Fluke Victoreen) and electrometer (RTI Solidose 400). Results: The CTDI measurements were within 20% of the console displayed values. The alignment and orientation for both gantry laser and tabletop, as well as the table movement and indexing and scanogram location accuracy were within 2mm as specified in TG66. The spatial resolution, low contrast resolution, field uniformity and CT number accuracy were all within ACR’s recommended limits. The mA linearity and reproducibility were both well below the TG66 threshold. Conclusion: The 90 cm bore size second generation Toshiba Aquilion Large Bore CT simulator that comes with 70 cm true FOV can consistently meet various clinical needs. The results demonstrated that this simulator complies with the TG-66 protocol in all aspects including electromechanical component

  1. Seventh-generation CT

    Science.gov (United States)

    Besson, G. M.

    2016-03-01

    A new dual-drum CT system architecture has been recently introduced with the potential to achieve significantly higher temporal resolution than is currently possible in medical imaging CT. The concept relies only on known technologies; in particular rotation speeds several times higher than what is possible today could be achieved leveraging typical x-ray tube designs and capabilities. However, the architecture lends itself to the development of a new arrangement of x-ray sources in a toroidal vacuum envelope containing a rotating cathode ring and a (optionally rotating) shared anode ring to potentially obtain increased individual beam power as well as increase total exposure per rotation. The new x-ray source sub-system design builds on previously described concepts and could make the provision of multiple conventional high-power cathodes in a CT system practical by distributing the anode target between the cathodes. In particular, relying on known magnetic-levitation technologies, it is in principle possible to more than double the relative speed of the electron-beam with respect to the target, thus potentially leading to significant individual beam power increases as compared to today's state-of-the-art. In one embodiment, the proposed design can be naturally leveraged by the dual-drum CT concept previously described to alleviate the problem of arranging a number of conventional rotating anode-stem x-ray tubes and power conditioners on the limited space of a CT gantry. In another embodiment, a system with three cathodes is suggested leveraging the architecture previously proposed by Franke.

  2. Recurrent bladder carcinoma: clinical and prognostic role of 18 F-FDG PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Alongi, Pierpaolo [San Raffaele G. Giglio Institute, Department of Radiological Sciences, Nuclear Medicine Unit, Cefalu (Italy); Caobelli, Federico [Basel University Hospital, Department of Nuclear Medicine, Basel (Switzerland); Gentile, Roberta; Baldari, Sergio [University of Messina, Nuclear Medicine Unit, Department of Biomedical Sciences and Morphological and Functional Images, Messina (Italy); Stefano, Alessandro; Russo, Giorgio; Gilardi, Maria Carla [IBFM-CNR, Cefalu (Italy); Albano, Domenico [Universita degli Studi di Palermo, DIBIMEF - Sezione di Scienze Radiologiche, Palermo (Italy); Midiri, Massimo [San Raffaele G. Giglio Institute, Department of Radiological Sciences, Nuclear Medicine Unit, Cefalu (Italy); Universita degli Studi di Palermo, DIBIMEF - Sezione di Scienze Radiologiche, Palermo (Italy)

    2017-02-15

    A small number of studies evaluated the detection rate of lesions from bladder carcinoma (BC) of 18 F-FDG PET/CT in the restaging process. However, the prognostic role of FDG PET/CT still remains unclear. The aim of the present study was to evaluate the accuracy, the effect upon treatment decision, and the prognostic value of FDG PET/CT in patients with suspected recurrent BC. Forty-one patients affected by BC underwent FDG PET/CT for restaging purpose. The diagnostic accuracy of visually interpreted FDG PET/CT was assessed compared to histology (n = 8), other diagnostic imaging modalities (contrast-enhanced CT in 38/41 patients and MRI in 15/41) and clinical follow-up (n = 41). Semiquantitative PET values (SUVmax, SUVmean, SUL, MTV, TLG) were calculated using a graph-based method. Progression-free survival (PFS) and overall survival (OS) were assessed by using Kaplan-Meier curves. The risk of progression (hazard ratio, HR) was computed by Cox regression analysis by considering all the available variables. PET was considered positive in 21 of 41 patients. Of these, recurrent BC was confirmed in 20 (95 %). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET/CT were 87 %, 94 %, 95 %, 85 %, 90 %. AUC was 0.9 (95 %IC 0.8-1). Bayesian positive and negative likelihood ratios were 14.5 and 0.13, respectively. FDG PET/CT findings modified the therapeutic approach in 16 patients (modified therapy in 10 PET-positive patients, watch-and-wait in six PET-negative patients). PFS was significantly longer in patients with negative scan vs. those with pathological findings (85 % vs. 24 %, p < 0.05; HR = 12.4; p = 0.001). Moreover, an unremarkable study was associated with a longer OS (88 % vs. 47 % after 2 years and 87 % vs. 25 % after 3 years, respectively, p < 0.05). Standardized uptake value (SUV)max > 6 and total lesion glycolysis (TLG) > 8.5 were recognized as the most accurate thresholds to predict PFS (2-year PFS 62 % for

  3. CT urography

    Energy Technology Data Exchange (ETDEWEB)

    Korobkin, M. [Dept. of Radiology, Univ. of Michigan, Ann Arbor, MI (United States)

    2005-11-15

    With the advent of multidetector row CT scanners, evaluation of the urothelium of the entire urinary tract with high-resolution thin sections during a single breath-hold has become a reality. Multidetector CT urography (MDCTU) is a single examination that allows evaluation of potential urinary tract calculi, renal parenchymal masses, and both benign and malignant urothelial lesions. Initial results with this new technique are encouraging. Current investigations of MDCTU focus on methods to improve opacification and distension of the upper urinary tract - the collecting systems, pelvis, and ureters. The role of abdominal compression, infusion of saline and/or furosemide, and optimal time delay of excretory phase imaging is being explored. Upper tract urothelial malignancies, including small lesions less the 5 mmin diameter, can be detected with high sensitivity. Methods to reduce radiation exposure are being explored, including split-bolus contrast injection techniques that combine nephrographic and excretory phases into a single phase. It is likely that in the near future, radiological evaluation of significant unexplained hematuria or of known or prior urothelial malignancy will consist of a single examination - MDCTU. (orig.)

  4. SPECT/CT in neuroendocrine cancers; SPECT/CT bei neuroendokrinen Tumoren

    Energy Technology Data Exchange (ETDEWEB)

    Miederer, M. [Technische Univ. Muenchen (Germany). Nuklearmedizinische Klinik und Poliklinik; Mainz Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Castrop, C.; Scheidhauer, K. [Technische Univ. Muenchen (Germany). Nuklearmedizinische Klinik und Poliklinik; Buck, A.K. [Universitaetsklinikum Wuerzburg (Germany). Nuklearmedizinische Klinik und Poliklinik

    2011-03-15

    The accuracy of functional SPECT imaging has been significantly improved by addition of CT. This is especially relevant for functional imaging of neuroendocrine tumors using highly specific radiopharmaceuticals. Parathyroid adenomas can be detected by {sup 99m}Tc-MIBI SPECT/CT with very high sensitivity and specificity, playing an important role especially when minimally invasive techniques are used for surgical resection. With SPECT/CT, extra-adrenal manifestations of pheochromocytomas and tumors of the adrenal cortex can be detected with high accuracy. Because of the availability of PET radiopharmaceuticals such as {sup 68}Ga-DOTATOC, the clinical relevance of {sup 111}In-Octreotide SPECT for detection of neuroendocrine cancers has been recently reduced. Because of the better availability, SPECT and SPECT/CT still represent standard tools for imaging neuroendocrine cancers. SPECT/CT represents the superior imaging modality for monitoring radiopeptide based therapies, which are now increasingly used for treatment of neuroendocrine cancers. (orig.)

  5. Poster — Thur Eve — 11: Validation of the orthopedic metallic artifact reduction tool for CT simulations at the Ottawa Hospital Cancer Centre

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, J; Foottit, C [The Ottawa Hospital Cancer Centre (Canada)

    2014-08-15

    Metallic implants in patients can produce image artifacts in kilovoltage CT simulation images which can introduce noise and inaccuracies in CT number, affecting anatomical segmentation and dose distributions. The commercial orthopedic metal artifact reduction algorithm (O-MAR) (Philips Healthcare System) was recently made available on CT simulation scanners at our institution. This study validated the clinical use of O-MAR by investigating its effects on CT number and dose distributions. O-MAR corrected and uncorrected images were acquired with a Philips Brilliance Big Bore CT simulator of a cylindrical solid water phantom that contained various plugs (including metal) of known density. CT number accuracy was investigated by determining the mean and standard deviation in regions of interest (ROI) within each plug for uncorrected and O-MAR corrected images and comparing with no-metal image values. Dose distributions were calculated using the Monaco treatment planning system. Seven open fields were equally spaced about the phantom around a ROI near the center of the phantom. These were compared to a “correct” dose distribution calculated by overriding electron densities a no-metal phantom image to produce an image containing metal but no artifacts. An overall improvement in CT number and dose distribution accuracy was achieved by applying the O-MAR correction. Mean CT numbers and standard deviations were found to be generally improved. Exceptions included lung equivalent media, which is consistent with vendor specified contraindications. Dose profiles were found to vary by ±4% between uncorrected or O-MAR corrected images with O-MAR producing doses closer to ground truth.

  6. 320排容积CT血管成像在颅内动脉瘤诊断中的准确性%Accuracy of 320-detector volume CT angiography in the diagnosis of intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    陈文华; 邢伟; 何忠明; 彭亚; 王祁

    2015-01-01

    Objective To assess the accuracy of 320-detector volume CTA (VCTA) in the diagnosis of intracranial aneurysms.Methods A total of 462 patients suspected with intracranial aneurysm in the Department of Interventional Radiology,the Third Affiliated Hospital of Soochow University from February 2011 to October 2014 were performed 320-detector VCTA and digital subtraction angiographic (DSA) examinations.Results In 462 patients,313 patients with intracranial aneurysm were diagnosed by 3D-DSA and a total of 381 intracranial aneurysms were detected.Ten intracranial aneurysms were missed by non-subtracted VCTA and one aneurysm was misdiagnosed.The sensitivity,specificity,and accuracy of non-subtracted VCTA diagnosed < 3 mm intracranial aneurysm were 91.7%,99.3% and 96.8%,respectively.Two aneurysms were missed by subtracted VCTA and 1 aneurysm was misdiagnosed.The sensitivity,specificity,and accuracy of subtracted VCTA for diagnosis of < 3 mm intracranial aneurysms were 97.2%,99.3%,and 98.6%,respectively.As for the statistical results of the diagnosis of intracranial aneurysms,there were significant differences between the non-subtracted VCTA and subtracted VCTA,and the non-subtracted VCTA and 3D-DSA (all P < 0.05);while there was no significant difference between subtracted VCTA and 3D-DSA (P > 0.05).Conclusions The accuracy of subtracted 320-detector VCTA in the diagnosis of < 3 mm intracranial aneurysms is higher.It can be used as the preferred imaging examination for diagnosis of intracranial aneurysms.The non-subtracted 320-detector VCTA relatively easily misses the diagnosis of intracranial aneurysms near the skull.%目的 评价320排容积CT血管成像(VCTA)在颅内动脉瘤诊断中的准确性.方法 收集2011年2月至2014年10月苏州大学附属第三医院神经外科收治的疑诊颅内动脉瘤患者462例,行320排VCTA和数字减影血管造影(DSA)检查.结果 462例患者中,通过3D-DSA确诊颅内动脉瘤患者313

  7. A Novel Reporting System to Improve Accuracy in Appendicitis Imaging

    Science.gov (United States)

    Godwin, Benjamin D.; Drake, Frederick T.; Simianu, Vlad V.; Shriki, Jabi E.; Hippe, Daniel S.; Dighe, Manjiri; Bastawrous, Sarah; Cuevas, Carlos; Flum, David; Bhargava, Puneet

    2015-01-01

    OBJECTIVE The purpose of this study was to ascertain if standardized radiologic reporting for appendicitis imaging increases diagnostic accuracy. MATERIALS AND METHODS We developed a standardized appendicitis reporting system that includes objective imaging findings common in appendicitis and a certainty score ranging from 1 (definitely not appendicitis) through 5 (definitely appendicitis). Four radiologists retrospectively reviewed the preoperative CT scans of 96 appendectomy patients using our reporting system. The presence of appendicitis-specific imaging findings and certainty scores were compared with final pathology. These comparisons were summarized using odds ratios (ORs) and the AUC. RESULTS The appendix was visualized on CT in 89 patients, of whom 71 (80%) had pathologically proven appendicitis. Imaging findings associated with appendicitis included appendiceal diameter (odds ratio [OR] = 14 [> 10 vs appendicitis. In this initially indeterminate group, using the standardized reporting system, radiologists assigned higher certainty scores (4 or 5) in 21 of the 28 patients with appendicitis (75%) and lower scores (1 or 2) in five of the seven patients without appendicitis (71%) (AUC = 0.90; p = 0.001). CONCLUSION Standardized reporting and grading of objective imaging findings correlated well with postoperative pathology and may decrease the number of CT findings reported as indeterminate for appendicitis. Prospective evaluation of this reporting system on a cohort of patients with clinically suspected appendicitis is currently under way. PMID:26001230

  8. Planning and clinical studies of a commercial orthopedic metal artifact reduction tool for CT simulations for head-and-neck radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kon, Hyuck Jun; Ye, Sung Joon [Interdisplinary Program in Radiation Applied Life Science, Seoul National University Graduate School, Seoul (Korea, Republic of); Kim, Jung In; Park, Jong Min; Lee, Jae Gi; Heo, Tae Min [Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul (Korea, Republic of); Kim Kyung Su [Dept. of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Chun, Young Mi [Philips Healthcare Korea, Seoul (Korea, Republic of); Callahan, Zachariah [Program in Biomedical Radiation Sciences, Dept. of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul (Korea, Republic of)

    2013-11-15

    In computed tomography (CT) images, the presence of high Z materials induces typical streak artifacts, called metal artifacts which can pervert CT Hounsfield numbers in the reconstructed images. These artifact-induced distortion of CT images can impact on the dose calculation based on the CT images. In the radiation therapy of Head-and-Neck cancer because of the concave-shaped target volumes, the complex anatomy, a lot of sensitive normal tissues and air cavity structures, it is important to get accurate CT images for dose calculation. But dental implant is common for H and N patients so that it is hard to get undistorted CT images. Moreover because dental implants are generally with the air cavity like oral cavity and nasal cavity in the same CT slice, they can make lots of distortion. In this study, we focused on evaluating the distortion on air cavity by the metal artifact and the effectiveness of the commercial orthopedic metal artifact reduction function (O-MAR) about the metal artifacts induced by the dental implant. The O-MAR algorithm increases the accuracy of CT Hounsfield numbers and reducing noises. Thus, it can contribute to the entire radiation treatment planning process, especially for contouring/segmentation. Although there was no significant difference in dose distributions for most cases, the O-MAR correction was shown to have an impact on high dose regions in air cavity.

  9. Feasibility and Diagnostic Accuracy for Assessment of Coronary Artery Stenosis of Prospectively Electrocardiogram-gated High-pitch Spiral Acquisition Mode Dual-source CT Coronary Angiography in Patients with Relatively Higher Heart Rates:in Comparison wit

    Institute of Scientific and Technical Information of China (English)

    Kai Sun; Rui-juan Han; Li-fang Cui; Rui-ping Zhao; Li-jun Ma; Li-jun Wang; Li-gang Li; Chang-yong Li

    2012-01-01

    Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography coronary angiography (CTCA) in patients with relatively higher heart rates (HR) compared with catheter coronary angiography (CCA).Methods Forty-seven consecutive patients with relatively higher HR (>65 and < 100 bpm) (20 male,27 female; age 55 ± 10 years) who both underwent dual-source CTCA and CCA were prospectively included in this study.All patients were performed CTCA using high pitch mode setting at 20%-30% of the R-R interval for the image acquisition.All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a three-point scale (1:excellent to 3:non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%).Considered CCA as the standard of reference,the sensitivity,specificity,positive predictive value and negative predictive value were calculated.Radiation dose values were calculated using the dose-length product.Results Image quality was rated as being score 1 in 92.4% of segments,score 2 in 6.1% of segments and score 3 in 1.5% of segments.The average image quality score per segment was 1.064±0.306.The HR variability of patients with image score 1,2 and 3 were 2.29± 1.06 bpm,5.17± 1.37 bpm,8.88± 1.53 bpm,respectively.The average HR variability of patients with different image scores were significantly different (F=170.402,P=0.001).The sensitivity,specificity,positive and negative predictive values were 92.6%,97.0%,87.6%,98.3%,respe ctively,per segment and 90.0%,95.2%,85.3%,96.9%,respectively,per vessel and 100%,63.6%,90.0%,100%,respectively,per patient.The effective radiation dose was on average 0.86±0.16 mSv.Conclusion In patients with HR more than 65 bpm and below 100 bpm without cardiac arrhythmia

  10. Spiral CT of Non-Graft Post Cardiac Surgery Complications: A Pictorial Essay

    Directory of Open Access Journals (Sweden)

    S. Shirani

    2010-06-01

    Full Text Available Spiral CT is a rapidly growing method for noninvasive visualization of post-operative complications, including post-operative complications in CABG (coronary artery bypass graft. In the recent years, several different, yet more efficient types have been introduced with progressive improvement in the diagnostic accuracy in the detection of post-operative complications. The introduction of 64-slice technology, which allows high resolution as well as reconstructed images, has resulted in further progress in the diagnostic process. This kind of diagnostic equipment will spread rapidly in the world. Although studies with large numbers of patients regarding spiral CT as a routine diagnostic method have not been reported, there is great need for it all over the world. In this article, we intend to review the spiral CT findings of non-graft complications in patients after cardiac surgery.

  11. Mucinous cystadenoma of the appendix: CT findings

    Institute of Scientific and Technical Information of China (English)

    ZHOU Mei-ling; YAN Fu-hua; XU Peng-ju; ZHANG Li-jun; LI Qing-hai; JI Yuan

    2006-01-01

    @@ Appendiceal mucinous cystadenoma (AMC) is an uncommon disease. The clinical symptoms are non-specific, thus the preoperative diagnosis is very difficult. The importance of recognizing this condition lies in preventing spillage during surgery. At present,the widespread use of computed tomography (CT)for evaluating abdominal disease has increased the detection rate and diagnostic accuracy for AMC.Here, we report the CT appearance of 4histologically proven AMCs.

  12. Clinical value of FDG PET or PET/CT in urinary bladder cancer: A systemic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yu-Yu, E-mail: yuoyuolu@vghtc.gov.tw [Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung, Taiwan (China); Chen, Jin-Hua, E-mail: chenjh99@mail.cmu.edu.tw [Biostatistics Center and Graduate Institute of Biostatistics, China Medical University, Taichung, Taiwan (China); Liang, Ji-An, E-mail: hope.jal@msa.hinet.net [Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan (China); School of Medicine, China Medical University, Taichung, Taiwan (China); Wang, Hsin-Yi, E-mail: hywang@vghtc.gov.tw [Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung, Taiwan (China); Lin, Cheng-Chieh, E-mail: cclin@mail.cmuh.org.tw [School of Medicine, China Medical University, Taichung, Taiwan (China); Department of Community Medicine and Health Examination Center, China Medical University Hospital, Taichung, Taiwan (China); Lin, Wan-Yu, E-mail: wylin@vghtc.gov.tw [Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung, Taiwan (China); School of Medicine, China Medical University, Taichung, Taiwan (China); Kao, Chia-Hung, E-mail: d10040@mail.cmuh.org.tw [School of Medicine, China Medical University, Taichung, Taiwan (China); Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan (China)

    2012-09-15

    Aim: The purpose of the current study was to conduct a systemic review and meta-analysis of the published literature to evaluate the diagnostic accuracy of FDG PET or PET/CT in urinary bladder cancer. Materials and methods: The authors conducted a systematic MEDLINE search of articles published between January 2000 and December 2010. Two reviewers independently assessed the methodological quality of each study. We conducted a meta-analysis of pooled sensitivity and specificity in detecting primary and metastatic lesions of bladder cancer. Results: Six studies met the inclusion criteria. The pooled sensitivity and specificity of PET/CT for primary lesion detection of bladder cancer were 0.90 (95% CI: 0.70–0.99) and 1.00 (95% CI: 0.74–1.00), respectively. The pooled sensitivity and specificity of FDG PET or PET/CT for staging or restaging (metastatic lesions) of bladder cancer were 0.82 (95% CI: 0.72–0.89) and 0.89 (95% CI: 0.81–0.95), respectively. Conclusion: The diagnostic accuracy of FDG PET or PET/CT is good in metastatic lesions of urinary bladder cancer. Due to the small number of patients and limited number of studies analyzed, the diagnostic capability of FDG PET or PET/CT in detection of primary bladder wall lesions could not be assessed.

  13. CT enterography: technical and interpretive pitfalls.

    Science.gov (United States)

    Barlow, John M; Goss, Brian C; Hansel, Stephanie L; Kolbe, Amy B; Rackham, Joshua L; Bruining, David H; Fletcher, Joel G

    2015-06-01

    CT enterography is a first-line test at many institutions to investigate potential small bowel disorders. While numerous articles have focused on the ability of CT enterography to diagnose and stage Crohn's disease, small bowel neoplasia, and malabsorptive or vascular disorders, this article reviews CT enterography limitations, technical and interpretive pitfalls, image review tactics, and complementary radiologic and endoscopic examinations to improve diagnostic accuracy. CT enterography limitations include its inability to demonstrate isolated mucosal abnormalities such as aphthous ulcers and its use of ionizing radiation. The most common technical pitfall of CT enterography is inadequate small bowel distention resulting from inadequate ingestion, gastric retention, or rapid small bowel transit of a large volume of neutral enteric contrast material. Additionally, segments of jejunum are frequently collapsed. Interpretive pitfalls commonly result from peristaltic contractions, transient intussusception and opaque intraluminal debris. Opaque debris is especially problematic during multiphasic CT enterography performed to identify potential small bowel sources of obscure gastrointestinal bleeding. False-negative examinations may result from inadequate radiation dose. Examinations complementary to CT enterography include small bowel follow through, enteroclysis, CT enteroclysis, MR enterography, MR enteroclysis, capsule endoscopy, and balloon-assisted endoscopy. Properly performed and accurately interpreted CT enterography contributes to the diagnosis and management of small bowel disease by itself and as a complement to other radiologic and optical small bowel imaging examinations.

  14. SPECT/CT and pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Mortensen, Jann [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); The Faroese National Hospital, Department of Medicine, Torshavn (Faroe Islands); Gutte, Henrik [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Herlev Hospital, Copenhagen University Hospital, Department of Radiology, Copenhagen (Denmark); University of Copenhagen, Cluster for Molecular Imaging, Faculty of Health Sciences, Copenhagen (Denmark)

    2014-05-15

    Acute pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/P) scintigraphy or pulmonary CT angiography (CTPA). In recent years both techniques have improved. Many nuclear medicine centres have adopted the single photon emission CT (SPECT) technique as opposed to the planar technique for diagnosing PE. SPECT has been shown to have fewer indeterminate results and a higher diagnostic value. The latest improvement is the combination of a low-dose CT scan with a V/P SPECT scan in a hybrid tomograph. In a study comparing CTPA, planar scintigraphy and SPECT alone, SPECT/CT had the best diagnostic accuracy for PE. In addition, recent developments in the CTPA technique have made it possible to image the pulmonary arteries of the lungs in one breath-hold. This development is based on the change from a single-detector to multidetector CT technology with an increase in volume coverage per rotation and faster rotation. Furthermore, the dual energy CT technique is a promising modality that can provide functional imaging in combination with anatomical information. Newer high-end CT scanners and SPECT systems are able to visualize smaller subsegmental emboli. However, consensus is lacking regarding the clinical impact and treatment. In the present review, SPECT and SPECT in combination with low-dose CT, CTPA and dual energy CT are discussed in the context of diagnosing PE. (orig.)

  15. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... a relatively short time, especially when compared to magnetic resonance imaging (MRI). CT scanning is painless, noninvasive and accurate. A ... CT is less sensitive to patient movement than MRI. CT can be performed if you have an ...

  16. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... CT is less sensitive to patient movement than MRI. CT can be performed if you have an implanted medical device of any kind, unlike MRI. A diagnosis determined by CT scanning may eliminate ...

  17. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... CT Scanning of the Abdomen and Pelvis? What is CT Scanning of the Abdomen/Pelvis? Computed tomography, ... the body being studied. top of page How is the CT scan performed? The technologist begins by ...

  18. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... additional view capabilities. Modern CT scanners are so fast that they can scan through large sections of ... after the procedure? CT exams are generally painless, fast and easy. With multidetector CT, the amount of ...

  19. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... 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 ...

  20. Abdominal and Pelvic CT

    Science.gov (United States)

    ... 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 ...

  1. FDG-PET/contrast-enhanced CT as a post-treatment tool in head and neck squamous cell carcinoma: comparison with FDG-PET/non-contrast-enhanced CT and contrast-enhanced CT

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Yuko; Kitajima, Kazuhiro; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Ishihara, Takeaki; Sasaki, Ryohei [Kobe University Graduate, School of Medicine, Department of Radiology, Division of Radiation Oncology, Kobe (Japan); Otsuki, Naoki; Nibu, Ken-ichi [Kobe University Graduate, School of Medicine, Department of Otolaryngology-Head and Neck Surgery, Kobe (Japan); Minamikawa, Tsutomu [Kobe University Graduate School of Medicine, Department of Oral and Maxillofacial Surgery, Kobe (Japan); Kiyota, Naomi [Kobe University Hospital, Department of Medical Oncology and Hematology, Kobe (Japan)

    2016-04-15

    To evaluate the accuracy of PET/CT using {sup 18}F-fluorodeoxyglucose (FDG) with IV contrast for suspected recurrent head and neck squamous cell carcinoma (HNSCC). One hundred and seventy patients previously treated for HNSCC underwent PET/CT, consisting of non-contrast-enhanced and contrast-enhanced CT, to investigate suspected recurrence. Diagnostic performance of PET/contrast-enhanced CT (PET/ceCT), PET/non-contrast-enhanced CT (PET/ncCT) and contrast-enhanced CT (ceCT) for local or regional recurrence, distant metastasis, overall recurrence and second primary cancer was evaluated. The reference standard included histopathology, treatment change and imaging follow-up. The patient-based areas under the receiver operating characteristic curves (AUC) for ceCT, PET/ncCT and PET/ceCT were 0.82, 0.96 and 0.98 for local recurrence, 0.73, 0.86 and 0.86 for regional recurrence, 0.86, 0.91 and 0.92 for distant metastasis, 0.72, 0.86 and 0.87 for overall recurrence, and 0.86, 0.89 and 0.91 for a second primary cancer. Both PET/ceCT and PET/ncCT statistically showed larger AUC than ceCT for recurrence, and the difference between PET/ceCT and PET/ncCT for local recurrence reached a significant level (p = 0.039). The accuracy of PET/ceCT for diagnosing overall recurrence was high, irrespective of the time interval after the last treatment (83.3-94.1 %). FDG-PET/CT was a more accurate HNSCC restaging tool than ceCT. The added value of ceCT at FDG-PET/CT is minimal. (orig.)

  2. SPECT/CT and pulmonary embolism

    DEFF Research Database (Denmark)

    Mortensen, Jann; Borgwardt, Henrik Gutte

    2014-01-01

    Acute pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/P) scintigraphy or pulmonary CT angiography (CTPA). In recent years both techniques have improved. Many nuclear medicine centres have adopted the single photon emission CT (SPECT) technique as opposed to the planar...... technique for diagnosing PE. SPECT has been shown to have fewer indeterminate results and a higher diagnostic value. The latest improvement is the combination of a low-dose CT scan with a V/P SPECT scan in a hybrid tomograph. In a study comparing CTPA, planar scintigraphy and SPECT alone, SPECT/CT had...... the best diagnostic accuracy for PE. In addition, recent developments in the CTPA technique have made it possible to image the pulmonary arteries of the lungs in one breath-hold. This development is based on the change from a single-detector to multidetector CT technology with an increase in volume...

  3. Reducing radiation dose in CT enterography.

    Science.gov (United States)

    Del Gaizo, Andrew J; Fletcher, Joel G; Yu, Lifeng; Paden, Robert G; Spencer, Garrett Clay; Leng, Shuai; Silva, Annelise M; Fidler, Jeff L; Silva, Alvin C; Hara, Amy K

    2013-01-01

    Computed tomographic (CT) enterography is a diagnostic examination that is increasingly being used to evaluate disorders of the small bowel. An undesirable consequence of CT, however, is patient exposure to ionizing radiation. This is of particular concern with CT enterography because patients tend to be young and require numerous follow-up examinations. There are multiple strategies to reduce radiation dose at CT enterography, including adjusting acquisition parameters, reducing scan length, and reducing tube voltage or tube current. The drawback to dose reduction strategies is degradation of image quality due to increased image noise. However, image noise can be reduced with commercial iterative reconstruction and denoising techniques. With a combination of low-dose techniques and noise-control strategies, one can markedly reduce radiation dose at CT enterography while maintaining diagnostic accuracy.

  4. Utility of CT in branemark implant treatment

    Energy Technology Data Exchange (ETDEWEB)

    Yosue, Takashi; Takamori, Hitoshi; Nomura, Atsushi; Watanabe, Kaichi; Kamezawa, Hiroshi; Ohtani, Kazuo; Hiraga, Yasushi; Nakaya, Hiroshi (Nippon Dental Univ., Tokyo (Japan))

    1992-12-01

    Since the implant prognosis depends on the diagnosis, we use CT or tomography in addition to ordinary radiographic procedures to diagnose the propriety. Here we would like to present the diagnostic value of CT. We have performed CT examinations for 55 patients (66 jaws) up to the end of May 1992. In addition to the one-dimensional observation of CT images, we routinely used reconstructed CT images for the valuation of bone quality and quantity. The reconstructed CT images provided precise information regarding the width and height of the alveolar creat. The axial CT view provides more precise information on jawbone structure than panoramic radiographs. The CT number gives a quick estimate of jawbone quality. Because the image reconstruction requires only axial CT radiographs, metal restorations on the opposite jaw do not affect radiographic images. We have to take into account the partial volume effect, though. The disadvantages of CT use in diagnosis are an increase of time and of patient irradiation. The clarity of lower jaw CTs are especially sensitive to the patient movement. In conclusion, the CT radiographs are valuable in implant diagnosis. (author).

  5. Efficacy of IV Buscopan as a muscle relaxant in CT colonography

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzi, John F.; Brennan, Darren D.; Fenlon, Helen M. [Department of Radiology, Mater Misericordiae Hospital, Eccles Street, Dublin 7 (Ireland); Moss, Alan C.; MacMathuna, Padraic [Department of Gastroenterology, Mater Misericordiae Hospital, Eccles Street, Dublin 7 (Ireland)

    2003-10-01

    The aim of this study was to examine the efficacy of IV Buscopan as a muscle relaxant in CT colonography in terms of colonic distension and polyp detection, and to determine its particular efficacy in patients with diverticular disease. Seventy-three consecutive patients were randomised to receive IV Buscopan or no muscle relaxant prior to CT colonography. CT colonography was performed using a Siemens Somatom 4-detector multislice CT scanner. The following parameters were recorded: degree of colonic distension using a 4-point scale; diagnostic adequacy of colonic distension; presence or absence of diverticular disease; and presence of colonic polyps. Accuracy of polyp detection was assessed using subsequent conventional colonoscopy as a gold standard. There was no significant difference between the two groups in the number of segments that were deemed to be optimally or adequately distended (p=0.37). Although IV Buscopan did improve distension of certain segments, this effect was not sufficient to improve the number of diagnostically adequate studies in the Buscopan group (p=0.14). In patients with diverticular disease, IV Buscopan did not have any significant effect on segments affected by diverticulosis but was associated with an improvement in distension of more proximal segments. There was no significant difference between the two groups in terms of polyp detection (p=0.34). The addition of prone scanning to supine scanning was found to be the most useful technique for maximising colonic distension. Intravenous Buscopan at CT colonography does not improve the overall adequacy of colonic distension nor the accuracy of polyp detection. In patients with sigmoid diverticular disease IV Buscopan improves distension of more proximal colonic segments and may be useful in selected cases, but our results do not support its routine use for CT colonography. (orig.)

  6. State of the art imaging of multiple myeloma: Comparative review of FDG PET/CT imaging in various clinical settings

    Energy Technology Data Exchange (ETDEWEB)

    Mesguich, Charles, E-mail: charles.mesguich@chu-bordeaux.fr [Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Fardanesh, Reza; Tanenbaum, Lawrence [Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Chari, Ajai; Jagannath, Sundar [Department of Medicine Division of Hematology and Oncology, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Kostakoglu, Lale, E-mail: lale.kostakoglu@mssm.edu [Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY (United States)

    2014-12-15

    Highlights: • Metabolic changes on FDG PET/CT offer an earlier response evaluation than MRI. • PET/CT is less sensitive than MRI for diffuse bone marrow involvement. • PET/CT is a highly sensitive modality to determine extra-medullary disease. • Red marrow expansion: false positive findings on both FDG PET/CT and MRI. • Compression fractures are best characterized with MRI. - Abstract: 18-Flurodeoxyglucose Positron Emission Tomography with computed tomography (FDG PET/CT) and Magnetic Resonance Imaging (MRI) have higher sensitivity and specificity than whole-body X-ray (WBXR) survey in evaluating disease extent in patients with multiple myeloma (MM). Both modalities are now recommended by the Durie–Salmon Plus classification although the emphasis is more on MRI than PET/CT. The presence of extra-medullary disease (EMD) as evaluated by PET/CT imaging, initial SUV{sub max} and number of focal lesions (FL) are deemed to be strong prognostic parameters at staging. MRI remains the most sensitive technique for the detection of diffuse bone marrow involvement in both the pre and post-therapy setting. Compression fractures are best characterized with MRI signal changes, for determining vertebroplasty candidates. While PET/CT allows for earlier and more specific evaluation of therapeutic efficacy compared to MRI, when signal abnormalities persist years after treatment. PET/CT interpretation, however, can be challenging in the vertebral column and pelvis as well as in cases with post-therapy changes. Hence, a reading approach combining the high sensitivity of MRI and superior specificity of FDG PET/CT would be preferred to increase the diagnostic accuracy. In summary, the established management methods in MM, mainly relying on biological tumor parameters should be complemented with functional imaging data, both at staging and restaging for optimal management of MM.

  7. EEG channels reduction using PCA to increase XGBoost's accuracy for stroke detection

    Science.gov (United States)

    Fitriah, N.; Wijaya, S. K.; Fanany, M. I.; Badri, C.; Rezal, M.

    2017-07-01

    In Indonesia, based on the result of Basic Health Research 2013, the number of stroke patients had increased from 8.3 ‰ (2007) to 12.1 ‰ (2013). These days, some researchers are using electroencephalography (EEG) result as another option to detect the stroke disease besides CT Scan image as the gold standard. A previous study on the data of stroke and healthy patients in National Brain Center Hospital (RS PON) used Brain Symmetry Index (BSI), Delta-Alpha Ratio (DAR), and Delta-Theta-Alpha-Beta Ratio (DTABR) as the features for classification by an Extreme Learning Machine (ELM). The study got 85% accuracy with sensitivity above 86 % for acute ischemic stroke detection. Using EEG data means dealing with many data dimensions, and it can reduce the accuracy of classifier (the curse of dimensionality). Principal Component Analysis (PCA) could reduce dimensionality and computation cost without decreasing classification accuracy. XGBoost, as the scalable tree boosting classifier, can solve real-world scale problems (Higgs Boson and Allstate dataset) with using a minimal amount of resources. This paper reuses the same data from RS PON and features from previous research, preprocessed with PCA and classified with XGBoost, to increase the accuracy with fewer electrodes. The specific fewer electrodes improved the accuracy of stroke detection. Our future work will examine the other algorithm besides PCA to get higher accuracy with less number of channels.

  8. CT-based interstitial HDR brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kolotas, C.; Baltas, D.; Zamboglou, N. [Staedtische Kliniken Offenbach (Germany). Strahlenklinik

    1999-09-01

    Purpose: Development, application and evaluation of a CT-guided implantation technique and a fully CT-based treatment planning procedure for brachytherapy. Methods and Materials: A brachytherapy procedure based on CT-guided implantation technique and CT-based treatment planning has been developed and clinical evaluated. For this purpose a software system (PROMETHEUS) for the 3D reconstruction of brachytherapy catheters and patient anatomy using only CT scans has been developed. An interface for the Nucletron PLATO BPS treatment planning system for optimization and calculation of dose distribution has been devised. The planning target volume(s) are defined as sets of points using contouring tools and are used for optimization of the 3D dose distribution. Dose-volume histogram based analysis of the dose distribution (COIN analysis) enables a clinically realistic evaluation of the brachytherapy application to be made. The CT-guided implantation of catheters and the CT-based treatment planning procedure has been performed for interstitial brachytherapy and for different tumor sites in 197 patients between 1996 and 1997. Results: The accuracy of the CT reconstruction was tested using first a quality assurance phantom and second, a simulated interstitial implant of 12 needles. These were compared with the results of reconstruction using radiographs. Both methods gave comparable results with regard to accuracy, but the CT based reconstruction was faster. Clinical feasibility was proved in pre-irradiated recurrences of brain tumors, in pretreated recurrences or metastatic disease, and in breast carcinomas. The tumor volumes treated were in the range 5.1 to 2,741 cm{sup 3}. Analysis of implant quality showed a slightly significant lower COIN value for the bone implants, but no differences with respect to the planning target volume. Conclusions: The Offenbach system, incorporating the PROMETHEUS software for interstitial HDR brachytherapy has proved to be extremely valuable

  9. Rectal cancer staging: Multidetector-row computed tomography diagnostic accuracy in assessment of mesorectal fascia invasion.

    Science.gov (United States)

    Ippolito, Davide; Drago, Silvia Girolama; Franzesi, Cammillo Talei; Fior, Davide; Sironi, Sandro

    2016-05-28

    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. 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. 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, as compared to the

  10. 3D Reconstruction in Spiral Multislice CT Scans

    Directory of Open Access Journals (Sweden)

    M. Ghafouri

    2005-08-01

    strategies for volume data management, selection of rendering parameters, and features of data display. In addition, I present recent research on the accuracy of the technique in specific medical applications and discuss a number of current clinical applications of 3D volume rendering of spiral CT data.

  11. CT of pancreatitis

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Toshio (Nagasaki Univ. (Japan). School of Medicine)

    1990-09-01

    One hundred and two cases of acute and chronic pancreatitis were studied by computed tomography. Fluid collection was detected by CT in 45 cases, and the common extrapancreatic sites of involvement included the lesser sac (13 cases), anterior pararenal space (9 cases), transverse mesocolon (7 cases) and posterior pararenal space (5 cases). Ten cases of spontaneous resolution of pancreatic pseudocysts were encountered. Cystojejunostomy was done on 6 patients. A 4-to-6-weeks time interval has been currently accepted as necessary for pseudocyst wall maturation. However, the surgery was not possible in two patients in this series since the cyst wall was too thin. It is considered that the time over 3 months is required for surgical anastomosis of the cyst to the gastrointestinal tract. Pancreatic abscess has become the most common cause of death from pancreatitis. In this series pancreatic abscess occurred in 8 patients. Gas collection in the pancreas was observed in only one patient. In the other patients, pseudocysts had become infected and converted to abscesses. The CT number of 4 infected pseudocysts was less than 15 HU. Thus, it was not possible to distinguish infected from noninfected pseudocysts by CT. The author studied 9 patients with focal inflammatory mass of the pancreas with histologically proved severe fibrosis. All masses were small. Angiography showed occlusion or marked stenosis of the splenic vein in 3 cases. The postcontract CT (after intravenous bolus injection) in 7 cases of focal inflammatory mass demonstrated almost equal enhanced effect of the mass as compared with the adjacent normal pancreatic parenchyma. This finding is considered to be useful in distinguishing inflammatory mass from pancreatic carcinoma. (author).

  12. Design and validation of a CT-guided robotic system for lung cancer brachytherapy.

    Science.gov (United States)

    Dou, Huaisu; Jiang, Shan; Yang, Zhiyong; Sun, Luqing; Ma, Xiaodong; Huo, Bin

    2017-09-01

    of the robotic system was 0.49 ± 0.29 mm. Phantom experiments indicated that the accuracy of needle insertion was 1.5 ± 1.7 mm at a depth ranging from 30 to 80 mm. The time used to adjust the template to the target position was 12 min on average by robotic system automatically. An average of 30 min was saved compared with the manual positioning procedure in phantom experiments. This paper describes the design and experimental validation of a novel CT-guided robotic system for lung cancer brachytherapy. The robotic system was validated in a number of aspects which prove that it was capable of locating the template with clinically acceptable accuracy in the CT environment. All experimental results indicated that the system is reliable and ready to be applied to further studies on animals. © 2017 American Association of Physicists in Medicine.

  13. Clinical evaluation of a commercial orthopedic metal artifact reduction tool for CT simulations in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Li Hua; Noel, Camille; Chen, Haijian; Harold Li, H.; Low, Daniel; Moore, Kevin; Klahr, Paul; Michalski, Jeff; Gay, Hiram A.; Thorstad, Wade; Mutic, Sasa [Department of Radiation Oncology, Washington University, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California 90095 (United States); Department of Radiation Oncology, University of California San Diego, San Diego, California 92093 (United States); Philips Healthcare System, Cleveland, Ohio 44143 (United States); Department of Radiation Oncology, Washington University, St. Louis, Missouri 63110 (United States)

    2012-12-15

    Purpose: Severe artifacts in kilovoltage-CT simulation images caused by large metallic implants can significantly degrade the conspicuity and apparent CT Hounsfield number of targets and anatomic structures, jeopardize the confidence of anatomical segmentation, and introduce inaccuracies into the radiation therapy treatment planning process. This study evaluated the performance of the first commercial orthopedic metal artifact reduction function (O-MAR) for radiation therapy, and investigated its clinical applications in treatment planning. Methods: Both phantom and clinical data were used for the evaluation. The CIRS electron density phantom with known physical (and electron) density plugs and removable titanium implants was scanned on a Philips Brilliance Big Bore 16-slice CT simulator. The CT Hounsfield numbers of density plugs on both uncorrected and O-MAR corrected images were compared. Treatment planning accuracy was evaluated by comparing simulated dose distributions computed using the true density images, uncorrected images, and O-MAR corrected images. Ten CT image sets of patients with large hip implants were processed with the O-MAR function and evaluated by two radiation oncologists using a five-point score for overall image quality, anatomical conspicuity, and CT Hounsfield number accuracy. By utilizing the same structure contours delineated from the O-MAR corrected images, clinical IMRT treatment plans for five patients were computed on the uncorrected and O-MAR corrected images, respectively, and compared. Results: Results of the phantom study indicated that CT Hounsfield number accuracy and noise were improved on the O-MAR corrected images, especially for images with bilateral metal implants. The {gamma} pass rates of the simulated dose distributions computed on the uncorrected and O-MAR corrected images referenced to those of the true densities were higher than 99.9% (even when using 1% and 3 mm distance-to-agreement criterion), suggesting that dose

  14. Experimental study of CT test on the failure of acrylate spray-applied waterproof layer in the groundwater environment

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this study the computerized tomography (CT) was first used to quantitatively analyze the failure of acrylate spray-applied waterproof membrane in the groundwater environment. The results of the CT tests show that it is feasible to use the CT to quantitatively analyze the failure of the waterproof membrane and the CT method has the advantages of speediness and accuracy that can eliminate the fussy operation process in routine tests. The main conclusions summarized from the study are as follows. First, there are two combined-indexes that can be used to decide the failure of the spray-on waterproof layer: one is that the reduced percentage of the CT number of the spray-on waterproof layer is less than 40.0% and the other is that the variance of the CT number decreases first and then increases. Second, the applicability for the spray-on waterproof layer in the groundwater environment is the SO 24-concentration ≤ 1%, the Cl-concentration ≤ 7.5% and the pH value ≤ 12.0 of the groundwater, respectively.

  15. CT features of appendiceal mucocele

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Won Jong; Byun, Jae Young; Jung, Jung Im; Lee, Hae Gyu; Park, Young Ha; Shin, Kyung Sub [Catholic University Medical College, Seoul (Korea, Republic of)

    1995-10-15

    To evaluate the usefulness of CT features of appendiceal mucocele in the diagnosis and evaluation of complications. We retrospectively reviewed CT findings and compared with operative findings in 7 cases of pathologically proven appendiceal mucocele. CT findings such as location and extent of the lesion, tissue density, thickness or calcification of the wall, presence of adjacent inflammatory infiltration, and visualization of normal vermiform appendix were analyzed. Appendiceal mucocele was found as homogeneous low density cystic mass adjacent to the cecum, which has no surrounding inflammatory infiltration except in one case of perforation and one case of intussusception. Mean CT number measured in 4 cases was 21 Hounsfield unit. Thin curvilinear calcifications were noted along the cystic wall in 2 cases. Normal vermiform appendix couldn't be demonstrated in all cases. Appendiceal mucocele is characterized by homogeneously low density and thin walled cystic tumor adjacent to cecum without surrounding inflammatory infiltration, and absence of normal vermiform appendix on CT. Therefore, CT is valuable in preventing operative complications of appendiceal mucocele.

  16. Multi-institutional MicroCT image comparison of image-guided small animal irradiators

    Science.gov (United States)

    Johnstone, Chris D.; Lindsay, Patricia; E Graves, Edward; Wong, Eugene; Perez, Jessica R.; Poirier, Yannick; Ben-Bouchta, Youssef; Kanesalingam, Thilakshan; Chen, Haijian; E Rubinstein, Ashley; Sheng, Ke; Bazalova-Carter, Magdalena

    2017-07-01

    To recommend imaging protocols and establish tolerance levels for microCT image quality assurance (QA) performed on conformal image-guided small animal irradiators. A fully automated QA software SAPA (small animal phantom analyzer) for image analysis of the commercial Shelley micro-CT MCTP 610 phantom was developed, in which quantitative analyses of CT number linearity, signal-to-noise ratio (SNR), uniformity and noise, geometric accuracy, spatial resolution by means of modulation transfer function (MTF), and CT contrast were performed. Phantom microCT scans from eleven institutions acquired with four image-guided small animal irradiator units (including the commercial PXi X-RAD SmART and Xstrahl SARRP systems) with varying parameters used for routine small animal imaging were analyzed. Multi-institutional data sets were compared using SAPA, based on which tolerance levels for each QA test were established and imaging protocols for QA were recommended. By analyzing microCT data from 11 institutions, we established image QA tolerance levels for all image quality tests. CT number linearity set to R 2  >  0.990 was acceptable in microCT data acquired at all but three institutions. Acceptable SNR  >  36 and noise levels  1.5 lp mm-1 for MTF  =  0.2) was obtained at all but four institutions due to their large image voxel size used (>0.275 mm). Ten of the eleven institutions passed the set QA tolerance for geometric accuracy (2000 HU for 30 mgI ml-1). We recommend performing imaging QA with 70 kVp, 1.5 mA, 120 s imaging time, 0.20 mm voxel size, and a frame rate of 5 fps for the PXi X-RAD SmART. For the Xstrahl SARRP, we recommend using 60 kVp, 1.0 mA, 240 s imaging time, 0.20 mm voxel size, and 6 fps. These imaging protocols should result in high quality images that pass the set tolerance levels on all systems. Average SAPA computation time for complete QA analysis for a 0.20 mm voxel, 400 slice Shelley phantom microCT data set

  17. Development of phantoms for spiral CT.

    Science.gov (United States)

    Goodenough, D J; Levy, J R; Kasales, C

    1998-01-01

    This paper reports on the development of a new phantom for spiral CT. The phantom meets the increased demands on phantom z-axis uniformity in order that objects from the CT slice, immediately above and below the CT slice of interest, do not contribute perturbing information to the reconstructed CT slice. The phantom depends on formulation of tissue-like materials that can be cast and produced in both geometric and anthropomorphic shapes with sufficient z-axis length to enable unperturbed CT slices of test objects of interest. These materials are then used to produce a series of test objects of CT image quality including low contrast samples that do not require volume averaging or mixing of solutions, and that can reflect sub-slice thickness test objects and supra-slice thickness test objects. The overall phantom and its individual test objects provides meaningful tests of spiral CT image quality including slice sensitivity, CT number linearity and tests of high and low contrast resolution. Schematic designs and actual CT scans are shown. The new spiral phantom appears to meet the increased demands of spiral CT on phantom design, particularly z-axis length, and requirements for low contrast resolution test objects.

  18. 3D CT protocol in the assessment of the esophageal neoplastic lesions: can it improve TNM staging?

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, V.; Grazhdani, H.; Iafrate, F.; Petroni, M.; Anzidei, M.; Laghi, A.; Passariello, R. [University of Rome La Sapienza, Department of Radiological Sciences, Rome (Italy)

    2006-02-01

    The purpose of this prospective observational study was the evaluation of the usefulness of MPR reconstructions and virtual endoscopy in the study of the esophageal carcinoma. Thirty-nine patients with esophageal cancer proved by means of endoscopy, underwent preoperative TNM staging with dynamic CT of the chest and abdomen with the aid of 3D rendering. Twenty-six patients underwent surgery, and the CT results were compared with histopathologic findings. In staging the T parameter, the CT with 3D reconstructions and virtual endoscopy, showed a sensitivity of 92% and an accuracy of 88%. In staging lymph nodes, the sensitivity in our study was 85%, the specificity 58%, and the accuracy 69%. Our protocol of the study of the esophageal cancer with 3D CT and virtual endoscopy, demonstrated a high concordance with the surgical and pathologic findings. The 3D reconstructed images were very helpful to the surgeons regarding preoperative planning. We performed an observational enquiry, and although this was a small study, it has, however, confirmed that the 3D imaging of the esophagus represents a valuable advantage to conventional imaging. Further studies with a larger number of patients are needed to prove its superiority to traditional CT imaging of the esophagus. (orig.)

  19. [Direct total body CT scan in multi-trauma patients

    NARCIS (Netherlands)

    Sierink, J.C.; Saltzherr, T.P.; Edwards, M.J.R.; Beuker, B.J.; Patka, P.; Goslings, J.C.; studiegroep, R.

    2012-01-01

    BACKGROUND: Immediate total body computed tomography (CT) scanning has become important in the early diagnostic phase of trauma care because of its high diagnostic accuracy. However, literature provides limited evidence whether immediate total body CT leads to better clinical outcome then convention

  20. Accuracy of the typical computed tomographic appearances of fibrosing alveolitis.

    Science.gov (United States)

    Tung, K T; Wells, A U; Rubens, M B; Kirk, J M; du Bois, R M; Hansell, D M

    1993-01-01

    BACKGROUND--Open lung biopsy is often performed to confirm the diagnosis in patients with suspected fibrosing alveolitis. The superior sensitivity and specificity of high resolution computed tomography (CT) over chest radiography in various diffuse lung diseases suggest that the characteristic appearance of fibrosing alveolitis on high resolution CT might render biopsy confirmation unnecessary. METHODS--The chest radiographs and high resolution CT scans of 86 patients (41 with fibrosing alveolitis and 45 with various other diffuse lung diseases) were examined individually and independently by two observers. No clinical information was given and the observers gave a level of confidence when the diagnosis was thought to be fibrosing alveolitis. RESULTS--The observers correctly and confidently discriminated between fibrosing alveolitis and other diffuse lung diseases on high resolution CT with an accuracy of 88% and on chest radiography with an accuracy of 76%. The false negative rate for fibrosing alveolitis diminished from 29% on chest radiography to 11% on high resolution CT. The false positive rate on chest radiography was 19% and on high resolution CT 13%; the false positive diagnoses on CT were the result of a few conditions (extrinsic allergic alveolitis, sarcoidosis, cryptogenic organising pneumonia, and pulmonary eosinophilia) which mimicked some of the CT features of fibrosing alveolitis. The superficial similarity of the CT patterns of these conditions are discussed. CONCLUSIONS--High resolution CT is superior to chest radiography in establishing the diagnosis of fibrosing alveolitis and the typical CT appearances are virtually pathognomonic. The diagnostic advantages of CT over chest radiography should further reduce the need for open lung biopsy in this condition. Images PMID:8135910

  1. Correction of oral contrast artifacts in CT-based attenuation correction of PET images using an automated segmentation algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadian, Alireza; Ay, Mohammad R.; Sarkar, Saeed [Medical Sciences/University of Tehran, Research Center for Science and Technology in Medicine, Tehran (Iran); Medical Sciences/University of Tehran, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran (Iran); Bidgoli, Javad H. [Medical Sciences/University of Tehran, Research Center for Science and Technology in Medicine, Tehran (Iran); East Tehran Azad University, Department of Electrical and Computer Engineering, Tehran (Iran); Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine, Geneva (Switzerland)

    2008-10-15

    Oral contrast is usually administered in most X-ray computed tomography (CT) examinations of the abdomen and the pelvis as it allows more accurate identification of the bowel and facilitates the interpretation of abdominal and pelvic CT studies. However, the misclassification of contrast medium with high-density bone in CT-based attenuation correction (CTAC) is known to generate artifacts in the attenuation map ({mu}map), thus resulting in overcorrection for attenuation of positron emission tomography (PET) images. In this study, we developed an automated algorithm for segmentation and classification of regions containing oral contrast medium to correct for artifacts in CT-attenuation-corrected PET images using the segmented contrast correction (SCC) algorithm. The proposed algorithm consists of two steps: first, high CT number object segmentation using combined region- and boundary-based segmentation and second, object classification to bone and contrast agent using a knowledge-based nonlinear fuzzy classifier. Thereafter, the CT numbers of pixels belonging to the region classified as contrast medium are substituted with their equivalent effective bone CT numbers using the SCC algorithm. The generated CT images are then down-sampled followed by Gaussian smoothing to match the resolution of PET images. A piecewise calibration curve was then used to convert CT pixel values to linear attenuation coefficients at 511 keV. The visual assessment of segmented regions performed by an experienced radiologist confirmed the accuracy of the segmentation and classification algorithms for delineation of contrast-enhanced regions in clinical CT images. The quantitative analysis of generated {mu}maps of 21 clinical CT colonoscopy datasets showed an overestimation ranging between 24.4% and 37.3% in the 3D-classified regions depending on their volume and the concentration of contrast medium. Two PET/CT studies known to be problematic demonstrated the applicability of the technique

  2. Diagnostic accuracy of computed tomography using lower doses of radiation for patients with Crohn's disease.

    LENUS (Irish Health Repository)

    Craig, Orla

    2012-08-01

    Magnetic resonance and ultrasonography have increasing roles in the initial diagnosis of Crohn\\'s disease, but computed tomography (CT) with positive oral contrast agents is most frequently used to identify those with acute extramural complications. However, CT involves exposure of patients to radiation. We prospectively compared the diagnostic accuracy of low-dose CT (at a dose comparable to that used to obtain an abdominal radiograph) with conventional-dose CT in patients with active Crohn\\'s disease.

  3. A phantom for testing of 4D-CT for radiotherapy of small lesions

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, L.; Kron, T.; Taylor, M. L.; Callahan, J.; Franich, R. D. [School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne 3000 (Australia); School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne 3000 (Australia) and Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne 3002 (Australia); School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne 3000 (Australia);