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Sample records for low-dose abdominal ct

  1. Screening of illegal intracorporeal containers ("body packing"): is abdominal radiography sufficiently accurate? A comparative study with low-dose CT.

    Science.gov (United States)

    Poletti, Pierre-Alexandre; Canel, Laurent; Becker, Christoph D; Wolff, Hans; Elger, Bernice; Lock, Eric; Sarasin, François; Bonfanti, Monica S; Dupuis-Lozeron, Elise; Perneger, Thomas; Platon, Alexandra

    2012-12-01

    To evaluate the diagnostic performance of abdominal radiography in the detection of illegal intracorporeal containers (hereafter, packets), with low-dose computed tomography (CT) as the reference standard. This study was approved by the institutional ethical review board, with written informed consent. From July 2007 to July 2010, 330 people (296 men, 34 women; mean age, 32 years [range, 18-55 years]) suspected of having ingested drug packets underwent supine abdominal radiography and low-dose CT. The presence or absence of packets at abdominal radiography was reported, with low-dose CT as the reference standard. The density and number of packets (≤ 12 or >12) at low-dose CT were recorded and analyzed to determine whether those variables influence interpretation of results at abdominal radiography. Packets were detected at low-dose CT in 53 (16%) suspects. Sensitivity of abdominal radiography for depiction of packets was 0.77 (41 of 53), and specificity was 0.96 (267 of 277). The packets appeared isoattenuated to the bowel contents at low-dose CT in 16 (30%) of the 53 suspects with positive results. Nineteen (36%) of the 53 suspects with positive low-dose CT results had fewer than 12 packets. Packets that were isoattenuated at low-dose CT and a low number of packets (≤12) were both significantly associated with false-negative results at abdominal radiography (P = .004 and P = .016, respectively). Abdominal radiography is mainly limited by low sensitivity when compared with low-dose CT in the screening of people suspected of carrying drug packets. Low-dose CT is an effective imaging alternative to abdominal radiography. © RSNA, 2012.

  2. The optimal parameter for radiation dose in pediatric low dose abdominal CT: cross-sectional dimensions versus body weight

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    Jung, Yoon Young; Goo, Hyun Woo [Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of)

    2008-02-15

    To investigate the best parameter between cross-sectional dimensions and body weight in pediatric low dose abdominal CT. One hundred and thirty six children consecutively underwent weight-based abdominal CT. The subjects consisted of group 1 (79 children, weight range 10.0-19.9 kg) and group 2 (57 children, weight range 20.0-39.9 kg). Abdominal cross-sectional dimensions including circumference, area, anteroposterior diameters and transverse diameters were calculated. Image noise (standard deviation of CT density) was measured by placing a region of interest in the posterior segment of the right hepatic lobe on a CT image at the celiac axis. The measured image noise was correlated with the cross-sectional abdominal dimensions and body weight for subjects in each group. In group 1 subjects,area, circumference, transverse diameter, anteroposterior diameter, and body weight showed a significant positive correlation with image noise in descending order({gamma} = 0.63, 0.62, 0.61, 0.51, and 0.49; {rho} < 0.0001). In group 2 subjects, transverse diameter, circumference, area, anteroposterior diameter, and body weight showed a significant positive correlation with image noise in descending order ({gamma} = 0.83, 0.82, 0.78, 0.71, and 0.71; {rho} < 0.0001). Cross-sectional dimensions such as area, circumference, and transverse diameter showed a higher positive correlation with image noise than body weight for pediatric low dose abdominal CT.

  3. Low-dose multidetector-row CT-angiography of abdominal aortic aneurysm after endovascular repair

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    Iezzi, R., E-mail: iezzir@virgilio.it [Department of Bioimaging and Radiological Sciences, Institute of Radiology, ' A. Gemelli' Hospital - Catholic University, L.go A Gemelli 8, 00168 Rome (Italy); Department of Clinical Science and Bioimaging, Section of Radiology, University ' G. D' Annunzio' , Chieti (Italy); Cotroneo, A.R.; Giammarino, A. [Department of Clinical Science and Bioimaging, Section of Radiology, University ' G. D' Annunzio' , Chieti (Italy); Spigonardo, F. [Department of Vascular Surgery, University ' G. D' Annunzio' , Chieti (Italy); Storto, M.L. [Department of Clinical Science and Bioimaging, Section of Radiology, University ' G. D' Annunzio' , Chieti (Italy)

    2011-07-15

    Purpose: To investigate the possibility of reducing radiation dose exposure while maintaining image quality using multidetector computed tomography angiography (MDCTA) with high-concentration contrast media in patients undergoing follow-up after endovascular aortic repair (EVAR) to treat abdominal aortic aneurysm. Materials and methods: In this prospective, single center, intra-individual study, patients underwent two consecutive MDCTA scans 6 months apart, one with a standard acquisition protocol (130 mAs/120 kV) and 120 mL of iomeprol 300, and one using a low dose protocol (100 mAs/80 kV) and 90 mL of iomeprol 400. Images acquired during the arterial phase of contrast enhancement were evaluated both qualitatively and quantitatively for image noise and intraluminal contrast enhancement. Results: Thirty adult patients were prospectively enrolled. Statistically significantly higher attenuation values were measured in the low-dose acquisition protocol compared to the standard protocol, from the suprarenal abdominal aorta to the common femoral artery (p < 0.0001; all vascular segments). Qualitatively, image quality was judged significantly (p = 0.0002) better with the standard protocol than with the low-dose protocol. However, no significant differences were found between the two protocols in terms of contrast-to-noise ratio (CNR) (13.63 {+-} 6.97 vs. 11.48 {+-} 8.13; p = 0.1058). An overall dose reduction of up to 74% was observed for the low-dose protocol compared with the standard protocol. Conclusion: In repeat follow-up examinations of patients undergoing EVAR for abdominal aortic aneurysm, a low-dose radiation exposure acquisition protocol provides substantially reduced radiation exposure while maintaining a constant CNR and good image quality.

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

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    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.)

  5. Low-dose multiphase abdominal CT reconstruction with phase-induced swap prior

    Science.gov (United States)

    Selim, Mona; Rashed, Essam A.; Kudo, Hiroyuki

    2016-10-01

    Multiphase abdominal CT is an imaging protocol in which the patient is scanned at different phases before and after the injection of a contrast agent. Reconstructed images with different concentrations of contrast material provide useful information for effective detection of abnormalities. However, several scanning during a short period of time eventually increase the patient radiation dose to a remarkable value up to a risky level. Reducing the patient dose by modulating the x-ray tube current or acquiring the projection data through a small number of views are known to degrade the image quality and reduce the possibility to be useful for diagnosis purpose. In this work, we propose a novel multiphase abdominal CT imaging protocol with patient dose reduction and high image quality. The image reconstruction cost function consists of two terms, namely the data fidelity term and penalty term to enforce the anatomical similarity in successive contrast phase reconstruction. The prior information, named phase-induced swap prior (PISP) is computed using total variation minimization of image acquired from different contrast phases. The new method is evaluated through a simulation study using digital abdominal phantom and real data and results are promising.

  6. Emergency assessment of patients with acute abdominal pain using low-dose CT with iterative reconstruction: a comparative study.

    Science.gov (United States)

    Poletti, Pierre-Alexandre; Becker, Minerva; Becker, Christoph D; Halfon Poletti, Alice; Rutschmann, Olivier T; Zaidi, Habib; Perneger, Thomas; Platon, Alexandra

    2017-08-01

    To determine if radiation dose delivered by contrast-enhanced CT (CECT) for acute abdominal pain can be reduced to the dose administered in abdominal radiography (<2.5 mSv) using low-dose CT (LDCT) with iterative reconstruction algorithms. One hundred and fifty-one consecutive patients requiring CECT for acute abdominal pain were included, and their body mass index (BMI) was calculated. CECT was immediately followed by LDCT. LDCT series was processed using 1) 40% iterative reconstruction algorithm blended with filtered back projection (LDCT-IR-FBP) and 2) model-based iterative reconstruction algorithm (LDCT-MBIR). LDCT-IR-FBP and LDCT-MBIR images were reviewed independently by two board-certified radiologists (Raters 1 and 2). Abdominal pathology was revealed on CECT in 120 (79%) patients. In those with BMI <30, accuracies for correct diagnosis by Rater 1 with LDCT-IR-FBP and LDCT-MBIR, when compared to CECT, were 95.4% (104/109) and 99% (108/109), respectively, and 92.7% (101/109) and 100% (109/109) for Rater 2. In patients with BMI ≥30, accuracies with LDCT-IR-FBP and LDCT-MBIR were 88.1% (37/42) and 90.5% (38/42) for Rater 1 and 78.6% (33/42) and 92.9% (39/42) for Rater 2. The radiation dose delivered by CT to non-obese patients with acute abdominal pain can be safely reduced to levels close to standard radiography using LDCT-MBIR. • LDCT-MBIR (<2.5 mSv) can be used to assess acute abdominal pain. • LDCT-MBIR (<2.5 mSv) cannot safely assess acute abdominal pain in obese patients. • LDCT-IR-FBP (<2.5 mSv) cannot safely assess patients with acute abdominal pain.

  7. [Indications for low-dose CT in the emergency setting].

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    Poletti, Pierre-Alexandre; Andereggen, Elisabeth; Rutschmann, Olivier; de Perrot, Thomas; Caviezel, Alessandro; Platon, Alexandra

    2009-08-19

    CT delivers a large dose of radiation, especially in abdominal imaging. Recently, a low-dose abdominal CT protocol (low-dose CT) has been set-up in our institution. "Low-dose CT" is almost equivalent to a single standard abdominal radiograph in term of dose of radiation (about one sixth of those delivered by a standard CT). "Low-dose CT" is now used routinely in our emergency service in two main indications: patients with a suspicion of renal colic and those with right lower quadrant pain. It is obtained without intravenous contrast media. Oral contrast is given to patients with suspicion of appendicitis. "Low-dose CT" is used in the frame of well defined clinical algorithms, and does only replace standard CT when it can reach a comparable diagnostic quality.

  8. Comparison of low dose with standard dose abdominal/pelvic multidetector CT in patients with stage 1 testicular cancer under surveillance

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    O' Malley, Martin E. [Joint Department of Medical Imaging, Toronto, ON (Canada); Chung, Peter; Warde, Padraig [Princess Margaret Hospital, Department of Radiation Oncology, Toronto, ON (Canada); Haider, Masoom; Jhaveri, Kartik; Khalili, Korosh [Princess Margaret Hospital, Joint Department of Medical Imaging, Toronto, ON (Canada); Jang, Hyun-Jung [Toronto General Hospital, Joint Department of Medical Imaging, Toronto, ON (Canada); Panzarella, Tony [Princess Margaret Hospital, Department of Biostatistics, Toronto, ON (Canada)

    2010-07-15

    To compare the image quality and acceptability of a low dose with those of standard dose abdominal/pelvic multidetector CT in patients with stage 1 testicular cancer managed by surveillance. One hundred patients (median age 31 years; range 19-83 years), 79 with seminoma and 21 with non-seminoma, underwent abdominal/pelvic imaging with low and standard dose protocols on 64-slice multidetector CT. Three reviewers independently evaluated images for noise and diagnostic quality on a 5-point scale and for diagnostic acceptability. On average, each reader scored noise and diagnostic quality of standard dose images significantly better than corresponding low dose images (p < 0.0001). One reader found all CT examinations acceptable; two readers each found 1/100 (1%) low dose examinations unacceptable. Median and mean dose-length product for low and standard dose protocols were 416.0 and 452.2 (range 122.9-913.4) and 931.9 and 999.8 (range 283.8-1,987.7) mGy cm, respectively. The low dose protocol provided diagnostically acceptable images for at least 99% of patients and achieved mean dose reduction of 55% compared with the standard dose protocol. (orig.)

  9. Objective evaluation of the correction by non-rigid registration of abdominal organ motion in low-dose 4D dynamic contrast-enhanced CT

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    Piper, Jim; Ikeda, Yoshihiro; Fujisawa, Yasuko; Ohno, Yoshiharu; Yoshikawa, Takeshi; O'Neil, Alison; Poole, Ian

    2012-03-01

    We objectively evaluate a straightforward registration method for correcting respiration-induced movement of abdominal organs in CT perfusion studies by measuring the distributions of alignment errors between corresponding landmark pairs. We introduce the concept and describe the advantages of using the surface-normal component of distance between pairs of corresponding landmarks selected so that their surface normal is in one of the three coordinate axis directions, and show that such landmarks can be precisely placed with respect to the surface normal. Using a large population of landmark pairs on a substantial quantity of 4D dynamic contrast-enhanced CT volume data, we quantify the average alignment errors of abdominal organs that remain uncorrected by registration.

  10. Low-dose versus standard-dose CT protocol in patients with clinically suspected renal colic.

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    Poletti, Pierre-Alexandre; Platon, Alexandra; Rutschmann, Olivier T; Schmidlin, Franz R; Iselin, Christophe E; Becker, Christoph D

    2007-04-01

    The purpose of our study was to compare a low-dose abdominal CT protocol, delivering a dose of radiation close to the dose delivered by abdominal radiography, with standard-dose unenhanced CT in patients with suspected renal colic. One hundred twenty-five patients (87 men, 38 women; mean age, 45 years) who were admitted with suspected renal colic underwent both abdominal low-dose CT (30 mAs) and standard-dose CT (180 mAs). Low-dose CT and standard-dose CT were independently reviewed, in a delayed fashion, by two radiologists for the characterization of renal and ureteral calculi (location, size) and for indirect signs of renal colic (renal enlargement, pyeloureteral dilatation, periureteral or renal stranding). Results reported for low-dose CT, with regard to the patients' body mass indexes (BMIs), were compared with those obtained with standard-dose CT (reference standard). The presence of non-urinary tract-related disorders was also assessed. Informed consent was obtained from all patients. In patients with a BMI 3 mm. Low-dose CT was 100% sensitive and specific for depicting non-urinary tract-related disorders (n = 6). Low-dose CT achieves sensitivities and specificities close to those of standard-dose CT in assessing the diagnosis of renal colic, depicting ureteral calculi > 3 mm in patients with a BMI < 30, and correctly identifying alternative diagnoses.

  11. Low-dose CT denoising with convolutional neural network

    CERN Document Server

    Chen, Hu; Zhang, Weihua; Liao, Peixi; Li, Ke; Zhou, Jiliu; Wang, Ge

    2016-01-01

    To reduce the potential radiation risk, low-dose CT has attracted much attention. However, simply lowering the radiation dose will lead to significant deterioration of the image quality. In this paper, we propose a noise reduction method for low-dose CT via deep neural network without accessing original projection data. A deep convolutional neural network is trained to transform low-dose CT images towards normal-dose CT images, patch by patch. Visual and quantitative evaluation demonstrates a competing performance of the proposed method.

  12. Low-Dose CT via Deep Neural Network

    CERN Document Server

    Chen, Hu; Zhang, Weihua; Liao, Peixi; Li, Ke; Zhou, Jiliu; Wang, Ge

    2016-01-01

    In order to reduce the potential radiation risk, low-dose CT has attracted more and more attention. However, simply lowering the radiation dose will significantly degrade the imaging quality. In this paper, we propose a noise reduction method for low-dose CT via deep learning without accessing the original projection data. An architecture of deep convolutional neural network was considered to map the low-dose CT images into its corresponding normal-dose CT images patch by patch. Qualitative and quantitative evaluations demonstrate a state-the-art performance of the proposed method.

  13. Screening for lung cancer with low-dose CT.

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    Coche, E

    2008-01-01

    Lung cancer represents the leading cause of cancer-related mortality in the world. In the past, many attempts were made to detect the disease at an early stage and subsequently reduce its mortality. Chest X-ray was abandoned for this purpose. For several years low-dose computed tomography has been introduced as a potential tool for early screening in a high-risk population. As demonstrated in several papers, the task is not easy and researchers are faced with many difficulties. This paper reviews mainly the role of low-dose CT for early cancer screening. Results of past and current trials, controversies related to the high rate of lung nodules, cost-effectiveness, and delivered radiation dose to the patient are presented. Finally some limitations of low dose CT for lung cancer detection are explained.

  14. Low-dose techniques in CT-guided interventions.

    Science.gov (United States)

    Sarti, Marc; Brehmer, William P; Gay, Spencer B

    2012-01-01

    Computed tomography (CT)-guided interventions such as biopsy, drainage, and ablation may be significant sources of radiation exposure in both patients and radiologists. Simple CT techniques to reduce radiation dose may be employed without increasing the procedure time or significantly degrading image quality. To develop low-dose protocols, it is important to understand the key concepts of delivered radiation dose to patients and physicians during CT-guided interventions. Patient dose estimates are easily followed and are provided at CT workstations. Familiarity with dose estimates, which are expressed as CT dose index and dose-length product, is also important. Methods to reduce radiation exposure in patients and physicians include performing proper preprocedure planning and paying careful attention to technique during the planning stage, making use of personal protective equipment, performing CT fluoroscopy intermittently instead of in real time, and optimizing needle visualization. Representative examples of these techniques have resulted in dose reductions of as much as 89%. Alternative imaging technologies that do not use ionizing radiation, such as virtual and ultrasonographic guidance, may also be used to reduce radiation dose. Understanding dose contribution strategies to reduce radiation dose provides a safer, more efficient environment for patients and the radiology team.

  15. Low dose CT perfusion using k-means clustering

    Science.gov (United States)

    Pisana, Francesco; Henzler, Thomas; Schönberg, Stefan; Klotz, Ernst; Schmidt, Bernhard; Kachelrieß, Marc

    2016-03-01

    We aim at improving low dose CT perfusion functional parameters maps and CT images quality, preserving quantitative information. In a dynamic CT perfusion dataset, each voxel is measured T times, where T is the number of acquired time points. In this sense, we can think about a voxel as a point in a T-dimensional space, where the coordinates of the voxels would be the values of its time attenuation curve (TAC). Starting from this idea, a k-means algorithm was designed to group voxels in K classes. A modified guided time-intensity profile similarity (gTIPS) filter was implemented and applied only for those voxels belonging to the same class. The approach was tested on a digital brain perfusion phantom as well as on clinical brain and body perfusion datasets, and compared to the original TIPS implementation. The TIPS filter showed the highest CNR improvement, but lowest spatial resolution. gTIPS proved to have the best combination of spatial resolution and CNR improvement for CT images, while k-gTIPS was superior to both gTIPS and TIPS in terms of perfusion maps image quality. We demonstrate k-means clustering analysis can be applied to denoise dynamic CT perfusion data and to improve functional maps. Beside the promising results, this approach has the major benefit of being independent from the perfusion model employed for functional parameters calculation. No similar approaches were found in literature.

  16. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... often used to determine the cause of unexplained pain. CT scanning is fast, painless, noninvasive and accurate. ... help diagnose the cause of abdominal or pelvic pain and diseases of the internal organs, small bowel ...

  17. Personalized low dose CT via variable kVp

    Science.gov (United States)

    Wang, Hui; Jin, Yannan; Yao, Yangyang; Wu, Mingye; Yan, Ming; Tao, Kun; Yin, Zhye; De Man, Bruno

    2015-03-01

    Computerized Tomography (CT) is a powerful radiographic imaging technology but the health risk due to the exposure of x-ray radiation has drawn wide concern. In this study, we propose to use kVp modulation to reduce the radiation dose and achieve the personalized low dose CT. Two sets of simulation are performed to demonstrate the effectiveness of kVp modulation and the corresponding calibration. The first simulation used the helical body phantom (HBP) that is an elliptical water cylinder with high density bone inserts. The second simulation uses the NCAT phantom to emulate the practical use of kVp modulation approach with region of interest (ROI) selected in the cardiac region. The kVp modulation profile could be optimized view by view based on the knowledge of patient attenuation. A second order correction is applied to eliminate the beam hardening artifacts. To simplify the calibration process, we first generate the calibration vectors for a few representative spectra and then acquire other calibration vectors with interpolation. The simulation results demonstrate the beam hardening artifacts in the images with kVp modulation can be eliminated with proper beam hardening correction. The results also show that the simplification of calibration did not impair the image quality: the calibration with the simplified and the complete vectors both eliminate the artifacts effectively and the results are comparable. In summary, this study demonstrates the feasibility of kVp modulation and gives a practical way to calibrate the high order beam hardening artifacts.

  18. Ultra-low dose CT attenuation correction for PET/CT

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    Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

    2012-01-01

    A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging.

  19. Limits of Ultra-Low Dose CT Attenuation Correction for PET/CT.

    Science.gov (United States)

    Xia, Ting; Alessio, Adam M; Kinahan, Paul E

    2010-01-29

    We present an analysis of the effects of ultra-low dose X-ray computerized tomography (CT) based attenuation correction for positron emission tomography (PET). By ultra low dose we mean less than approximately 5 mAs or 0.5 mSv total effective whole body dose. The motivation is the increased interest in using respiratory motion information acquired during the CT scan for both phase-matched CT-based attenuation correction and for motion estimation. Since longer duration CT scans are desired, radiation dose to the patient can be a limiting factor. In this study we evaluate the impact of reducing photon flux rates in the CT data on the reconstructed PET image by using the CATSIM simulation tool for the CT component and the ASIM simulation tool for the PET component. The CT simulation includes effects of the x-ray tube spectra, beam conditioning, bowtie filter, detector noise, and bean hardening correction. The PET simulation includes the effect of attenuation and photon counting. Noise and bias in the PET image were evaluated from multiple realizations of test objects. We show that techniques can be used to significantly reduce the mAs needed for CT based attenuation correction if the CT is not used for diagnostic purposes. The limiting factor, however, is not the noise in the CT image but rather the bias introduced by CT sinogram elements with no detected flux. These results constrain the methods that can be used to lower CT dose in a manner suitable for attenuation correction of PET data. We conclude that ultra-low-dose CT for attenuation correction of PET data is feasible with current PET/CT scanners.

  20. Low dose CT perfusion in acute ischemic stroke

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    Murphy, Amanda; Symons, Sean; Jakubovic, Raphael; Zhang, Liying; Aviv, Richard I. [Sunnybrook Health Sciences Centre, Toronto, ON (Canada); So, Aaron; Lee, Ting-Yim [Robarts Research Institute, London, Ontario (Canada)

    2014-12-15

    The purpose of this investigation is to determine if CT perfusion (CTP) measurements at low doses (LD = 20 or 50 mAs) are similar to those obtained at regular doses (RD = 100 mAs), with and without the addition of adaptive statistical iterative reconstruction (ASIR). A single-center, prospective study was performed in patients with acute ischemic stroke (n = 37; 54 % male; age = 74 ± 15 years). Two CTP scans were performed on each subject: one at 100 mAs (RD) and one at either 50 or 20 mAs (LD). CTP parameters were compared between the RD and LD scans in regions of ischemia, infarction, and normal tissue. Differences were determined using a within-subjects ANOVA (p < 0.05) followed by a paired t test post hoc analysis (p < 0.01). At 50 mAs, there was no significant difference between cerebral blood flow (CBF), cerebral blood volume (CBV), or time to maximum enhancement (Tmax) values for the RD and LD scans in the ischemic, infarcted, or normal contralateral regions (p < 0.05). At 20 mAs, there were significant differences between the RD and LD scans for all parameters in the ischemic and normal tissue regions (p > 0.05). CTP-derived CBF and CBV are not different at 50 mAs compared to 100 mAs, even without the addition of ASIR. Current CTP protocols can be modified to reduce the effective dose by 50 % without altering CTP measurements. (orig.)

  1. Evaluation of a low-dose CT protocol with oral contrast for assessment of acute appendicitis

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    Platon, Alexandra; Jlassi, Helmi; Becker, Christoph D.; Poletti, Pierre-Alexandre [University Hospital of Geneva, Department of Radiology, Geneva 14 (Switzerland); Rutschmann, Olivier T. [University Hospital of Geneva, Emergency Center, Geneva (Switzerland); Verdun, Francis R. [University Institute for Radiation Physics, Lausanne (Switzerland); Gervaz, Pascal [University Hospital of Geneva, Clinic of Digestive Surgery, Geneva (Switzerland)

    2009-02-15

    The aim of this study was to evaluate a low-dose CT with oral contrast medium (LDCT) for the diagnosis of acute appendicitis and compare its performance with standard-dose i.v. contrast-enhanced CT (standard CT) according to patients' BMIs. Eighty-six consecutive patients admitted with suspicion of acute appendicitis underwent LDCT (30 mAs), followed by standard CT (180 mAs). Both examinations were reviewed by two experienced radiologists for direct and indirect signs of appendicitis. Clinical and surgical follow-up was considered as the reference standard. Appendicitis was confirmed by surgery in 37 (43%) of the 86 patients. Twenty-nine (34%) patients eventually had an alternative discharge diagnosis to explain their abdominal pain. Clinical and biological follow-up was uneventful in 20 (23%) patients. LDCT and standard CT had the same sensitivity (100%, 33/33) and specificity (98%, 45/46) to diagnose appendicitis in patients with a body mass index (BMI) {>=} 18.5. In slim patients (BMI < 18.5), sensitivity to diagnose appendicitis was 50% (2/4) for LDCT and 100% (4/4) for standard CT, while specificity was identical for both techniques (67%, 2/3). LDCT may play a role in the diagnostic workup of patients with a BMI {>=} 18.5. (orig.)

  2. Abdominal aspergillosis: CT findings

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    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.

  3. Korean Society of Thoracic Radiology Guideline for Lung Cancer Screening with Low-Dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Ju [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Jin Hwan [Dept. of Radiology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon (Korea, Republic of); Kim, Yoon Kyung [Dept. of Radiology, Gachon University Gil Medical Center, Incheon (Korea, Republic of); Park, Chang Min [Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Jeong, Yeon Joo [Dept. of Radiology, Pusan National University Hospital, Pusan National University School of Medicine and Medical Research Institute, Busan (Korea, Republic of)

    2012-09-15

    The National Lung Screening Trial (NLST), a nation-wide randomized controlled trial involving more than 50,000 current and former heavy smokers ages 55 to 74, compared the effects of two screening procedures (low-dose helical CT and standard chest radiography) on lung cancer mortality and found 20 percent fewer lung cancer deaths among trial participants screened with low-dose CT. Korean Society of Thoracic Radiology (KSTR) planned to establish an effective guideline for lung cancer screening with low-dose CT to improve health of Korean people and to reduce harms from misuse of lung cancer screening with low-dose CT. KSTR guideline for lung cancer screening with low-dose CT established based on objective medical evidences obtained by NLST.

  4. Low dose dynamic myocardial CT perfusion using advanced iterative reconstruction

    Science.gov (United States)

    Eck, Brendan L.; Fahmi, Rachid; Fuqua, Christopher; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2015-03-01

    Dynamic myocardial CT perfusion (CTP) can provide quantitative functional information for the assessment of coronary artery disease. However, x-ray dose in dynamic CTP is high, typically from 10mSv to >20mSv. We compared the dose reduction potential of advanced iterative reconstruction, Iterative Model Reconstruction (IMR, Philips Healthcare, Cleveland, Ohio) to hybrid iterative reconstruction (iDose4) and filtered back projection (FBP). Dynamic CTP scans were obtained using a porcine model with balloon-induced ischemia in the left anterior descending coronary artery to prescribed fractional flow reserve values. High dose dynamic CTP scans were acquired at 100kVp/100mAs with effective dose of 23mSv. Low dose scans at 75mAs, 50mAs, and 25mAs were simulated by adding x-ray quantum noise and detector electronic noise to the projection space data. Images were reconstructed with FBP, iDose4, and IMR at each dose level. Image quality in static CTP images was assessed by SNR and CNR. Blood flow was obtained using a dynamic CTP analysis pipeline and blood flow image quality was assessed using flow-SNR and flow-CNR. IMR showed highest static image quality according to SNR and CNR. Blood flow in FBP was increasingly over-estimated at reduced dose. Flow was more consistent for iDose4 from 100mAs to 50mAs, but was over-estimated at 25mAs. IMR was most consistent from 100mAs to 25mAs. Static images and flow maps for 100mAs FBP, 50mAs iDose4, and 25mAs IMR showed comparable, clear ischemia, CNR, and flow-CNR values. These results suggest that IMR can enable dynamic CTP at significantly reduced dose, at 5.8mSv or 25% of the comparable 23mSv FBP protocol.

  5. Evaluation of a low-dose CT protocol with oral contrast for assessment of acute appendicitis.

    Science.gov (United States)

    Platon, Alexandra; Jlassi, Helmi; Rutschmann, Olivier T; Becker, Christoph D; Verdun, Francis R; Gervaz, Pascal; Poletti, Pierre-Alexandre

    2009-02-01

    The aim of this study was to evaluate a low-dose CT with oral contrast medium (LDCT) for the diagnosis of acute appendicitis and compare its performance with standard-dose i.v. contrast-enhanced CT (standard CT) according to patients' BMIs. Eighty-six consecutive patients admitted with suspicion of acute appendicitis underwent LDCT (30 mAs), followed by standard CT (180 mAs). Both examinations were reviewed by two experienced radiologists for direct and indirect signs of appendicitis. Clinical and surgical follow-up was considered as the reference standard. Appendicitis was confirmed by surgery in 37 (43%) of the 86 patients. Twenty-nine (34%) patients eventually had an alternative discharge diagnosis to explain their abdominal pain. Clinical and biological follow-up was uneventful in 20 (23%) patients. LDCT and standard CT had the same sensitivity (100%, 33/33) and specificity (98%, 45/46) to diagnose appendicitis in patients with a body mass index (BMI) >or= 18.5. In slim patients (BMIor= 18.5.

  6. Improving abdomen tumor low-dose CT images using a fast dictionary learning based processing

    Science.gov (United States)

    Chen, Yang; Yin, Xindao; Shi, Luyao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis; Toumoulin, Christine

    2013-08-01

    In abdomen computed tomography (CT), repeated radiation exposures are often inevitable for cancer patients who receive surgery or radiotherapy guided by CT images. Low-dose scans should thus be considered in order to avoid the harm of accumulative x-ray radiation. This work is aimed at improving abdomen tumor CT images from low-dose scans by using a fast dictionary learning (DL) based processing. Stemming from sparse representation theory, the proposed patch-based DL approach allows effective suppression of both mottled noise and streak artifacts. The experiments carried out on clinical data show that the proposed method brings encouraging improvements in abdomen low-dose CT images with tumors.

  7. Low-dose aspirin and rupture of abdominal aortic aneurysm

    DEFF Research Database (Denmark)

    Wemmelund, Holger; Jørgensen, Trine M M; Høgh, Annette

    2016-01-01

    OBJECTIVE: The use of low-dose aspirin (acetylsalicylic acid [ASA]) has been suggested to attenuate growth of abdominal aortic aneurysms (AAAs), yet solid clinical evidence of this hypothesis is still missing. This study aimed to investigate whether preadmission ASA use influenced the risk...

  8. A new low-dose CT examination compared with standard-dose CT in the diagnosis of acute sinusitis

    Energy Technology Data Exchange (ETDEWEB)

    Hagtvedt, T.; Aaloekken, T.M.; Noetthellen, J.; Kolbenstvedt, A. [Department of Radiology, Rikshospitalet, 0027 Oslo (Norway)

    2003-05-01

    A low-dose CT of the paranasal sinuses was designed with few, thin sections, non-uniform intersection gaps, low milliampere settings and avoidance of direct radiation to the eye lens. The low-dose CT was prospectively compared with standard-dose CT in patients with suspicion of acute sinusitis. Forty-seven patients were examined with low-dose CT immediately after standard-dose CT. The effective dose and the lens dose were calculated and compared. Using standard-dose CT as a gold standard the sensitivity and specificity of low-dose CT was calculated for each sinus group. The effective dose and the lens dose of the low-dose CT were reduced to, respectively, 3 and 2% of the standard-dose CT. The diagnostic yield of the low-dose CT with regard to acute sinusitis was good with a high specificity ({>=}96%) for all sinus groups. The sensitivity was also high ({>=}95%) except for the frontal sinus where the sensitivity was 83%. Low-dose CT offers considerable dose reduction and should be the standard for imaging patients with suspected acute inflammatory paranasal disease. (orig.)

  9. Low-dose helical computed tomography (CT) in the perioperative workup of adolescent idiopathic scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Abul-Kasim, Kasim; Overgaard, Angelica; Maly, Pavel [Malmoe University Hospital, Department of Radiology, Section of Neuroradiology, University of Lund, Malmoe (Sweden); Ohlin, Acke [Malmoe University Hospital, Department of Orthopaedic Surgery, University of Lund, Malmoe (Sweden); Gunnarsson, Mikael [Malmoe University Hospital, Department of Radiation Physics, University of Lund, Malmoe (Sweden); Sundgren, Pia C. [University of Michigan Health Systems, Department of Radiology, Division of Neuroradiology, Ann Arbor (United States)

    2009-03-15

    The study aims were to estimate the radiation dose in patients examined with low dose spine CT and to compare it with that received by patients undergoing standard CT for trauma of the same region, as well as to evaluate the impact of dose reduction on image quality. Radiation doses in 113 consecutive low dose spine CTs were compared with those in 127 CTs for trauma. The inter- and intraobserver agreement in measurements of pedicular width, and vertebral rotation, measurements of signal-to-noise ratio and assessment of hardware status were the indicators in the evaluation of image quality. The effective dose of the low dose spine CT (0.37 mSv) was 20 times lower than that of a standard CT for trauma (13.09 mSv). This dose reduction conveyed no impact on image quality. This low dose spine CT protocol allows detailed evaluation that is necessary for preoperative planning and postoperative evaluation. (orig.)

  10. Coronary artery calcification scoring in low-dose ungated CT screening for lung cancer: interscan agreement.

    NARCIS (Netherlands)

    Jacobs, P.C.; Isgum, I.; Gondrie, M.J.; Mali, W.P.Th.; Ginneken, B. van; Prokop, M.; Graaf, Y. van der

    2010-01-01

    OBJECTIVE: In previous studies detection of coronary artery calcification (CAC) with low-dose ungated MDCT performed for lung cancer screening has been compared with detection with cardiac CT. We evaluated the interscan agreement of CAC scores from two consecutive low-dose ungated MDCT examinations.

  11. Coronary Artery Calcification Scoring in Low-Dose Ungated CT Screening for Lung Cancer : Interscan Agreement

    NARCIS (Netherlands)

    Jacobs, Peter C. A.; Isgum, Ivana; Gondrie, Martijn J. A.; Mali, Willem P. Th. M.; van Ginneken, Bram; Prokop, Mathias; van der Graaf, Yolanda

    2010-01-01

    OBJECTIVE. In previous studies detection of coronary artery calcification (CAC) with low-dose ungated MDCT performed for lung cancer screening has been compared with detection with cardiac CT. We evaluated the interscan agreement of CAC scores from two consecutive low-dose ungated MDCT examinations.

  12. 20 percent lower lung cancer mortality with low-dose CT vs chest X-ray

    Science.gov (United States)

    Scientists have found a 20 percent reduction in deaths from lung cancer among current or former heavy smokers who were screened with low-dose helical computed tomography (CT) versus those screened by chest X-ray.

  13. Usefulness of low-dose CT in the detection of pulmonary metastasis of gestational trophoblastic tumours

    Energy Technology Data Exchange (ETDEWEB)

    Xu, X.J. [Department of Radiology, First Affiliated Hospital, Woman Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Lou, F.L. [Department of Radiology, Woman Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Zhang, M.M. [Department of Radiology, First Affiliated Hospital, Woman Hospital, School of Medicine, Zhejiang University, Hangzhou (China)], E-mail: zhangminming@163.com; Pan, Z.M. [Department of Radiology, Woman Hospital, School of Medicine, Zhejiang University, Hangzhou (China); Zhang, L. [Department of Radiology, First Affiliated Hospital, Woman Hospital, School of Medicine, Zhejiang University, Hangzhou (China)

    2007-10-15

    Aim: To determine whether a low-dose spiral chest computed tomography (CT) examination could replace standard-dose chest CT in detecting pulmonary metastases in patients with gestational trophoblastic tumour (GTT). Materials and methods: In a prospective investigation, 67 chest CT examinations of 39 GTT patients were undertaken. All the patients underwent CT examinations using standard-dose (150 mAs, pitch 1, standard reconstruction algorithm) and low-dose (40 mAs, pitch 2, bone reconstruction algorithm) protocols. Two radiologists interpreted images independently. A metastasis was defined as a nodule within lung parenchyma that could not be attributed to a pulmonary vessel. The number of metastases detected with each protocol was recorded. The size of each lesion was measured and categorized as <5, 5-9.9, and {>=}10 mm. Wilcoxon's signed rank test was used to assess the difference between the numbers of lesion detected by the two protocols. Results: The CT dose index (CTDI) for the standard-dose and low-dose CT protocols was 10.4 mGy and 1.4 mGy, respectively. One thousand, six hundred, and eighty-two metastases were detected by standard-dose CT, and 1460 lesions by the low-dose protocol. The numbers detected by low-dose CT were significantly less than those detected by standard-dose CT (Z = -3.776, p < 0.001), especially for nodules smaller than 5 mm (Z = -4.167, p < 0.001). However, the disease staging and risk score of the patients were not affected by use of the low-dose protocol. Conclusion: Low-dose chest CT can be used as a staging and follow-up procedure for patients with GTT.

  14. Spectrotemporal CT data acquisition and reconstruction at low dose

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Darin P.; Badea, Cristian T., E-mail: cristian.badea@duke.edu [Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710 (United States); Lee, Chang-Lung [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Kirsch, David G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2015-11-15

    Purpose: X-ray computed tomography (CT) is widely used, both clinically and preclinically, for fast, high-resolution anatomic imaging; however, compelling opportunities exist to expand its use in functional imaging applications. For instance, spectral information combined with nanoparticle contrast agents enables quantification of tissue perfusion levels, while temporal information details cardiac and respiratory dynamics. The authors propose and demonstrate a projection acquisition and reconstruction strategy for 5D CT (3D + dual energy + time) which recovers spectral and temporal information without substantially increasing radiation dose or sampling time relative to anatomic imaging protocols. Methods: The authors approach the 5D reconstruction problem within the framework of low-rank and sparse matrix decomposition. Unlike previous work on rank-sparsity constrained CT reconstruction, the authors establish an explicit rank-sparse signal model to describe the spectral and temporal dimensions. The spectral dimension is represented as a well-sampled time and energy averaged image plus regularly undersampled principal components describing the spectral contrast. The temporal dimension is represented as the same time and energy averaged reconstruction plus contiguous, spatially sparse, and irregularly sampled temporal contrast images. Using a nonlinear, image domain filtration approach, the authors refer to as rank-sparse kernel regression, the authors transfer image structure from the well-sampled time and energy averaged reconstruction to the spectral and temporal contrast images. This regularization strategy strictly constrains the reconstruction problem while approximately separating the temporal and spectral dimensions. Separability results in a highly compressed representation for the 5D data in which projections are shared between the temporal and spectral reconstruction subproblems, enabling substantial undersampling. The authors solved the 5D reconstruction

  15. Smoking habits in the randomised Danish Lung Cancer Screening Trial with low-dose CT

    DEFF Research Database (Denmark)

    Ashraf, Haseem; Saghir, Zaigham; Dirksen, Asger

    2014-01-01

    to annual low-dose CT (CT group) and 2052 received no intervention (control group). Participants were current and ex-smokers (≥4 weeks abstinence from smoking) with a tobacco consumption of ≥20 pack years. Smoking habits were determined annually. Missing values for smoking status at the final screening...

  16. Fast reconstruction of low dose proton CT by sinogram interpolation

    Science.gov (United States)

    Hansen, David C.; Sangild Sørensen, Thomas; Rit, Simon

    2016-08-01

    Proton computed tomography (CT) has been demonstrated as a promising image modality in particle therapy planning. It can reduce errors in particle range calculations and consequently improve dose calculations. Obtaining a high imaging resolution has traditionally required computationally expensive iterative reconstruction techniques to account for the multiple scattering of the protons. Recently, techniques for direct reconstruction have been developed, but these require a higher imaging dose than the iterative methods. No previous work has compared the image quality of the direct and the iterative methods. In this article, we extend the methodology for direct reconstruction to be applicable for low imaging doses and compare the obtained results with three state-of-the-art iterative algorithms. We find that the direct method yields comparable resolution and image quality to the iterative methods, even at 1 mSv dose levels, while yielding a twentyfold speedup in reconstruction time over previously published iterative algorithms.

  17. Automated coronary artery calcification detection on low-dose chest CT images

    Science.gov (United States)

    Xie, Yiting; Cham, Matthew D.; Henschke, Claudia; Yankelevitz, David; Reeves, Anthony P.

    2014-03-01

    Coronary artery calcification (CAC) measurement from low-dose CT images can be used to assess the risk of coronary artery disease. A fully automatic algorithm to detect and measure CAC from low-dose non-contrast, non-ECG-gated chest CT scans is presented. Based on the automatically detected CAC, the Agatston score (AS), mass score and volume score were computed. These were compared with scores obtained manually from standard-dose ECG-gated scans and low-dose un-gated scans of the same patient. The automatic algorithm segments the heart region based on other pre-segmented organs to provide a coronary region mask. The mitral valve and aortic valve calcification is identified and excluded. All remaining voxels greater than 180HU within the mask region are considered as CAC candidates. The heart segmentation algorithm was evaluated on 400 non-contrast cases with both low-dose and regular dose CT scans. By visual inspection, 371 (92.8%) of the segmentations were acceptable. The automated CAC detection algorithm was evaluated on 41 low-dose non-contrast CT scans. Manual markings were performed on both low-dose and standard-dose scans for these cases. Using linear regression, the correlation of the automatic AS with the standard-dose manual scores was 0.86; with the low-dose manual scores the correlation was 0.91. Standard risk categories were also computed. The automated method risk category agreed with manual markings of gated scans for 24 cases while 15 cases were 1 category off. For low-dose scans, the automatic method agreed with 33 cases while 7 cases were 1 category off.

  18. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... accurate. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. ... kidney and bladder stones. abdominal aortic aneurysms (AAA), injuries to abdominal organs such as the spleen, liver, ...

  19. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... accurate. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. ... kidney and bladder stones. abdominal aortic aneurysms (AAA), injuries to abdominal organs such as the spleen, liver, ...

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... the scanner at one time such as with MRI. If an intravenous contrast material is used, you ... CT is less sensitive to patient movement than MRI. CT can be performed if you have an ...

  4. Abdominal and Pelvic CT

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... lives. CT has been shown to be a cost-effective imaging tool for a wide range of ...

  5. Abdominal and Pelvic CT

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    Full Text Available ... the cause of unexplained pain. CT scanning is fast, painless, noninvasive and accurate. In emergency cases, it ... additional view capabilities. Modern CT scanners are so fast that they can scan through large sections of ...

  6. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... prescribed procedure with your doctor, the medical facility staff and/or your insurance provider to get a ...

  7. Abdominal and Pelvic CT

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    Full Text Available ... CT scanner technique will be adjusted to their size and the area of interest to reduce the ... Patient undergoing computed tomography (CT) scan View full size with caption Pediatric Content Some imaging tests and ...

  8. Abdominal and Pelvic CT

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    Full Text Available ... page How should I prepare for the CT scan? You should wear comfortable, loose-fitting clothing to ... studied. top of page How is the CT scan performed? The technologist begins by positioning you on ...

  9. Abdominal and Pelvic CT

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    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  10. Abdominal and Pelvic CT

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits Viewing a CT scan, an experienced radiologist ... CT scans should have no immediate side effects. Risks There is always a slight chance of cancer ...

  11. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Ultrasound - Abdomen X- ...

  12. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... CT scanning is fast, painless, noninvasive and accurate. In emergency cases, it can reveal internal injuries and ... generated during a CT scan can be reformatted in multiple planes, and can even generate three-dimensional ...

  13. Abdominal and Pelvic CT

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    Full Text Available ... the cause of unexplained pain. CT scanning is fast, painless, noninvasive and accurate. In emergency cases, it ... additional view capabilities. Modern CT scanners are so fast that they can scan through large sections of ...

  14. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... microphone. top of page How does the procedure work? In many ways CT scanning works very much like other x-ray examinations. Different ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ...

  15. Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT studies for the diagnosis of uterine cancer recurrence

    Energy Technology Data Exchange (ETDEWEB)

    Kitajima, Kazuhiro [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Suzuki, Kayo [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Nakamoto, Yuji [Kyoto University Hospital, Department of Diagnostic Radiology, Kyoto (Japan); Onishi, Yumiko; Sakamoto, Setsu; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Senda, Michio [Institute of Biomedical Research and Innovation, Department of Molecular Imaging, Kobe (Japan); Kita, Masato [Kobe City Medical Center General Hospital, Department of Obstetrics and Gynecology, Kobe (Japan)

    2010-08-15

    To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated {sup 18}F-fluorodeoxyglucose (FDG) PET/CT studies for restaging of uterine cancer. A group of 100 women who had undergone treatment for uterine cervical (n=55) or endometrial cancer (n=45) underwent a conventional PET/CT scans with ldCT, and then a ceCT scan. Two observers retrospectively reviewed and interpreted the PET/ldCT and PET/ceCT images in consensus using a three-point grading scale (negative, equivocal, or positive) per patient and per lesion. Final diagnoses were obtained by histopathological examination, or clinical follow-up for at least 6 months. Patient-based analysis showed that the sensitivity, specificity and accuracy of PET/ceCT were 90% (27/30), 97% (68/70) and 95% (95/100), respectively, whereas those of PET/ldCT were 83% (25/30), 94% (66/70) and 91% (91/100), respectively. Sensitivity, specificity and accuracy did not significantly differ between two methods (McNemar test, p=0.48, p=0.48, and p=0.13, respectively). There were 52 sites of lesion recurrence: 12 pelvic lymph node (LN), 11 local recurrence, 8 peritoneum, 7 abdominal LN, 5 lung, 3 supraclavicular LN, 3 liver, 2 mediastinal LN, and 1 muscle and bone. The grading results for the 52 sites of recurrence were: negative 5, equivocal 0 and positive 47 for PET/ceCT, and negative 5, equivocal 4 and positive 43 for PET/ldCT, respectively. Four equivocal regions by PET/ldCT (local recurrence, pelvic LN metastasis, liver metastasis and muscle metastasis) were correctly interpreted as positive by PET/ceCT. PET/ceCT is an accurate imaging modality for the assessment of uterine cancer recurrence. Its use reduces the frequency of equivocal interpretations. (orig.)

  16. Abdominal and Pelvic CT

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    Full Text Available ... contrast materials and a metallic taste in your mouth that lasts for at most a minute or ... can diagnose many causes of abdominal pain or injury from trauma with very high accuracy, enabling faster ...

  17. Abdominal and Pelvic CT

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    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... GI) contrast exams and ultrasound are preferred for evaluation of acute abdominal conditions in babies, such as ...

  18. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... GI) contrast exams and ultrasound are preferred for evaluation of acute abdominal conditions in babies, such as ...

  19. Three-Dimensions Segmentation of Pulmonary Vascular Trees for Low Dose CT Scans

    Science.gov (United States)

    Lai, Jun; Huang, Ying; Wang, Ying; Wang, Jun

    2016-12-01

    Due to the low contrast and the partial volume effects, providing an accurate and in vivo analysis for pulmonary vascular trees from low dose CT scans is a challenging task. This paper proposes an automatic integration segmentation approach for the vascular trees in low dose CT scans. It consists of the following steps: firstly, lung volumes are acquired by the knowledge based method from the CT scans, and then the data are smoothed by the 3D Gaussian filter; secondly, two or three seeds are gotten by the adaptive 2D segmentation and the maximum area selecting from different position scans; thirdly, each seed as the start voxel is inputted for a quick multi-seeds 3D region growing to get vascular trees; finally, the trees are refined by the smooth filter. Through skeleton analyzing for the vascular trees, the results show that the proposed method can provide much better and lower level vascular branches.

  20. Reduced image noise at low-dose multidetector CT of the abdomen with prior image constrained compressed sensing algorithm.

    Science.gov (United States)

    Lubner, Meghan G; Pickhardt, Perry J; Tang, Jie; Chen, Guang-Hong

    2011-07-01

    To assess the effect of prior image constrained compressed sensing (PICCS) on noise reduction and image quality at low-dose computed tomography (CT). This HIPAA-compliant institutional review board-approved retrospective study was performed by using DICOM CT colonography data sets obtained in 20 adult patients. Informed consent was waived. Low-dose CT colonography was performed with 64-detector CT by using the standard protocol with mean effective dose per series of 3.06 mSv (range, 1.4-7.7 mSv). PICCS was applied to standard filtered back-projection (FBP) series. For FBP and PICCS series, mean and standard deviation (SD) of attenuation were obtained with 100-mm(2) circular region of interest (ROI) at six sites (240 soft-tissue, colonic gas, and subcutaneous fat measurements). Two abdominal radiologists reviewed two- and three-dimensional CT colonography displays and graded image quality with a five-point scale. Phantom studies were performed to compare spatial resolution and image quality between FBP and PICCS. Mean image noise and image quality scores were calculated and compared for clinical and phantom data sets. Bland-Altman, generalized estimating equation regression model, and Student t tests were used to obtain limits of agreement and to compare noise ratios and subjective image quality. Mean SD of attenuation (image noise) for ROIs was 38.0 for FBP and 12.2 for PICCS, corresponding to a noise-reduction factor of 3.1 (P < .001). Average noise reduction was 3.3 for soft tissue, 2.8 for air, and 3.0 for fat attenuation. Attenuation did not substantially change between FBP and PICCS images. Average two-dimensional image quality was 2.45 for FBP and 3.4 for PICCS (P < .001). Average three-dimensional image quality at three sites in the colon was 3.5 for FBP and 3.7 for PICCS (P = .34). Phantom data sets revealed no loss of spatial resolution in a line phantom and reduced noise in a liver tumor phantom when PICCS was compared with FBP. Application of PICCS to

  1. Abdominal and Pelvic CT

    Medline Plus

    Full Text Available ... images or pictures of the inside of the body. The cross-sectional images generated during a CT scan can be reformatted ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  2. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Yinghua [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Chen, Guang-Hong [Department of Medical Physics and Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Hacker, Timothy A.; Raval, Amish N. [Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Van Lysel, Michael S.; Speidel, Michael A., E-mail: speidel@wisc.edu [Department of Medical Physics and Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2014-07-15

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  3. [Gallstone ileus. Abdominal CT usefulness].

    Science.gov (United States)

    Sukkarieh, F; Brasseur, P; Bissen, L

    2004-06-01

    The authors report the case of a 93-year old woman referred to the emergency department and presenting with an intestinal obstruction. Abdominal CT reveals a biliary ileus caused by the migration and the impaction of a 3 cm gallstone in the small bowel. Surgical treatment by enterolithotomy was successful. In over 90% of cases, gallstone ileus is a complication of cholelithiasis and accounts for 25% of intestinal obstruction in patients over 65 years. To reduce morbidity and mortality, early diagnosis and prompt treatment are essential. Abdominal CT-scan is the gold standard technique.

  4. Statistical image reconstruction for low-dose CT using nonlocal means-based regularization.

    Science.gov (United States)

    Zhang, Hao; Ma, Jianhua; Wang, Jing; Liu, Yan; Lu, Hongbing; Liang, Zhengrong

    2014-09-01

    Low-dose computed tomography (CT) imaging without sacrifice of clinical tasks is desirable due to the growing concerns about excessive radiation exposure to the patients. One common strategy to achieve low-dose CT imaging is to lower the milliampere-second (mAs) setting in data scanning protocol. However, the reconstructed CT images by the conventional filtered back-projection (FBP) method from the low-mAs acquisitions may be severely degraded due to the excessive noise. Statistical image reconstruction (SIR) methods have shown potentials to significantly improve the reconstructed image quality from the low-mAs acquisitions, wherein the regularization plays a critical role and an established family of regularizations is based on the Markov random field (MRF) model. Inspired by the success of nonlocal means (NLM) in image processing applications, in this work, we propose to explore the NLM-based regularization for SIR to reconstruct low-dose CT images from low-mAs acquisitions. Experimental results with both digital and physical phantoms consistently demonstrated that SIR with the NLM-based regularization can achieve more gains than SIR with the well-known Gaussian MRF regularization or the generalized Gaussian MRF regularization and the conventional FBP method, in terms of image noise reduction and resolution preservation.

  5. Abdominal and Pelvic CT

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the ...

  6. Abdominal and Pelvic CT

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    Full Text Available ... CT scanning procedure. For exams (excluding head and neck) your head will remain outside the hole in ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ...

  7. Abdominal and Pelvic CT

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    Full Text Available ... liver, shows up in shades of gray, and air appears black. With CT scanning, numerous x-ray ... injected into a vein) to help evaluate blood vessels and organs such as the liver, kidneys and ...

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    Full Text Available ... CT exam to be stressful. The technologist or nurse, under the direction of a physician, may offer ... to you, revolve around you during the imaging process. You will be alone in the exam room ...

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    Full Text Available ... hours prior to your exam. Leave jewelry at home and wear loose, comfortable clothing. You may be ... the CT images and should be left at home or removed prior to your exam. You may ...

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    Full Text Available ... liver, shows up in shades of gray, and air appears black. With CT scanning, numerous x-ray ... cause blurring of the images and degrade the quality of the examination the same way that it ...

  11. Abdominal and Pelvic CT

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    Full Text Available ... tomography (CT) scan View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

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    Full Text Available ... your exam. You should inform your physician of all medications you are taking and if you have ... body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a ...

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    Full Text Available ... or thyroid problems. Any of these conditions may increase the risk of an unusual adverse effect. Women ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ...

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    Full Text Available ... or liver cirrhosis. cancers of the liver, kidneys, pancreas, ovaries and bladder as well as lymphoma. kidney ... and organs such as the liver, kidneys and pancreas. When you enter the CT scanner, special light ...

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    Full Text Available ... an image on a special electronic image recording plate. Bones appear white on the x-ray; soft ... which are then displayed on a monitor. CT imaging is sometimes compared to looking into a loaf ...

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    ... an image on a special electronic image recording plate. Bones appear white on the x-ray; soft ... which are then displayed on a monitor. CT imaging is sometimes compared to looking into a loaf ...

  18. Abdominal and Pelvic CT

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    Full Text Available ... many types of tissue as well as the lungs, bones, and blood vessels. CT examinations are fast ... of many areas of the body, particularly the lungs, abdomen, pelvis and bones. A diagnosis determined by ...

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    Full Text Available ... to arriving. top of page What will I experience during and after the procedure? CT exams are ... at most a minute or two. You may experience a sensation like you have to urinate; however, ...

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    Full Text Available ... See the Safety page for more information about pregnancy and x-rays. top of page What does ... See the Safety page for more information about pregnancy and x-rays. CT scanning is, in general, ...

  1. Abdominal and Pelvic CT

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    Full Text Available ... Radiation Therapy for Bladder Cancer Radiation Therapy for Colorectal Cancer top of page This page was reviewed on ... GI Tract X-ray (Radiography) - Upper GI Tract Colorectal Cancer Images related to Computed Tomography (CT) - Abdomen and ...

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    Full Text Available ... rays used in CT scans should have no immediate side effects. Risks There is always a slight ... possible charges you will incur. Web page review process: This Web page is reviewed regularly by a ...

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    Full Text Available ... tissue as well as the lungs, bones, and blood vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. ...

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    Full Text Available ... during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images and ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the ...

  5. Abdominal and Pelvic CT

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    Full Text Available ... tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like ... contrast materials and a metallic taste in your mouth that lasts for at most a minute or ...

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    Full Text Available ... have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may ... particularly the lungs, abdomen, pelvis and bones. A diagnosis determined by CT scanning may eliminate the need ...

  7. Abdominal and Pelvic CT

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    Full Text Available ... preferable over CT scanning. top of page Additional Information and Resources RTAnswers.org: Radiation Therapy for Bladder ... Send us your feedback Did you find the information you were looking for? Yes No Please type ...

  8. Abdominal and Pelvic CT

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ...

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    Full Text Available ... pancreas. When you enter the CT scanner, special light lines may be seen projected onto your body, ... in the womb. The risk of serious allergic reaction to contrast materials that contain iodine is extremely ...

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    Full Text Available ... to obtain images. For children, the CT scanner technique will be adjusted to their size and the ... evaluation with additional views or a special imaging technique. A follow-up examination may also be necessary ...

  11. Abdominal and Pelvic CT

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    Full Text Available ... of electronic x-ray detectors rotate around you, measuring the amount of radiation being absorbed throughout your ... pancreas. When you enter the CT scanner, special light lines may be seen projected onto your body, ...

  12. Abdominal and Pelvic CT

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    Full Text Available ... lives. CT has been shown to be a cost-effective imaging tool for a wide range of ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  13. Abdominal and Pelvic CT

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    Full Text Available ... emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. Tell your ... emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has ...

  14. Abdominal and Pelvic CT

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    Full Text Available ... to remove hearing aids and removable dental work. Women will be asked to remove bras containing metal ... increase the risk of an unusual adverse effect. Women should always inform their physician and the CT ...

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    Full Text Available ... Leave jewelry at home and wear loose, comfortable clothing. You may be asked to wear a gown. ... CT scan? You should wear comfortable, loose-fitting clothing to your exam. You may be given a ...

  16. Abdominal and Pelvic CT

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    Full Text Available ... to wear a lead apron to minimize radiation exposure. After a CT exam, the intravenous line used ... always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate ...

  17. Abdominal and Pelvic CT

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... to urinate; however, this is actually a contrast effect and subsides quickly. If the contrast material is ...

  18. Abdominal and Pelvic CT

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    Full Text Available ... microphone. top of page How does the procedure work? In many ways CT scanning works very much ... these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2017 Radiological ...

  19. Abdominal and Pelvic CT

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    Full Text Available ... painless, noninvasive and accurate. In emergency cases, it can reveal internal injuries and bleeding quickly enough to ... cross-sectional images generated during a CT scan can be reformatted in multiple planes, and can even ...

  20. Abdominal and Pelvic CT

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    Full Text Available ... you are pregnant and discuss any recent illnesses, medical conditions, medications you’re taking, and allergies. You ... a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces multiple ...

  1. Abdominal and Pelvic CT

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    Full Text Available ... scanning is fast, painless, noninvasive and accurate. In emergency cases, it can reveal internal injuries and bleeding ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding ...

  2. Abdominal and Pelvic CT

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    Full Text Available ... CT) of the abdomen and pelvis is a diagnostic imaging test used to help detect diseases of the ... a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you ...

  3. Abdominal and Pelvic CT

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    Full Text Available ... treatments. plan for and assess the results of surgery, such as organ transplants. stage, plan and properly ... CT scanning may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a ...

  4. Abdominal and Pelvic CT

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    Full Text Available ... as: infections such as appendicitis , pyelonephritis or infected fluid collections, also known as abscesses. inflammatory bowel disease ... caused by a burst appendix or an infected fluid collection and the subsequent spread of infection. CT ...

  5. Abdominal and Pelvic CT

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    Full Text Available ... Abdomen and Pelvis? What is CT Scanning of the Abdomen/Pelvis? Computed tomography, more commonly known as ... of page What are some common uses of the procedure? This procedure is typically used to help ...

  6. Abdominal and Pelvic CT

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    Full Text Available ... entire body will be "inside" the scanner at one time such as with MRI. If an intravenous ... CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, ...

  7. Abdominal and Pelvic CT

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    Full Text Available ... as ulcerative colitis or Crohn's disease , pancreatitis or liver cirrhosis. cancers of the liver, kidneys, pancreas, ovaries and bladder as well as ... injuries to abdominal organs such as the spleen, liver, kidneys or other internal organs in cases of ...

  8. Abdominal and Pelvic CT

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    Full Text Available ... to help diagnose the cause of abdominal or pelvic pain and diseases of the internal organs, small bowel and colon, such as: infections such as appendicitis , pyelonephritis or infected fluid collections, also known as abscesses. inflammatory bowel disease such as ulcerative colitis or Crohn's ...

  9. Volumetric measurement of pulmonary nodules at low-dose chest CT : effect of reconstruction setting on measurement variability

    NARCIS (Netherlands)

    Wang, Y.; de Bock, G.H.; van Klaveren, R.J.; van Ooyen, P.; Tukker, W.; Zhao, Y.; Dorrius, M.D.; Proenca, R.V.; Post, W.J.; Oudkerk, M.

    2010-01-01

    To assess volumetric measurement variability in pulmonary nodules detected at low-dose chest CT with three reconstruction settings. The volume of 200 solid pulmonary nodules was measured three times using commercially available semi-automated software of low-dose chest CT data-sets reconstructed wit

  10. Optimised low-dose multidetector CT protocol for children with cranial deformity

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, Jose Luis [Complejo Hospitalario Universitario de Vigo, Department of Radiology, Vigo, Pontevedra (Spain); Pombar, Miguel Angel [Complejo Hospitalario Universitario de Santiago, Department of Radiophysics, Santiago de Compostela, La Coruna (Spain); Pumar, Jose Manuel [Complejo Hospitalario Universitario de Santiago, Department of Radiology, Santiago de Compostela, La Coruna (Spain); Campo, Victor Miguel del [Complejo Hospitalario Universitario de Vigo, Department of Public Health, Vigo, Pontevedra (Spain)

    2013-08-15

    To present an optimised low-dose multidetector computed tomography (MDCT) protocol for the study of children with cranial deformity. Ninety-one consecutive MDCT studies were performed in 80 children. Studies were performed with either our standard head CT protocol (group 1, n = 20) or a low-dose cranial deformity protocol (groups 2 and 3). Group 2 (n = 38), initial, and group 3 (n = 33), final and more optimised. All studies were performed in the same 64-MDCT equipment. Cranial deformity protocol was gradationally optimised decreasing kVp, limiting mA range, using automatic exposure control (AEC) and increasing the noise index (NI). Image quality was assessed. Dose indicators such us CT dose index volume (CTDIvol), dose-length product (DLP) and effective dose (E) were used. The optimised low-dose protocol reached the following values: 80 kVp, mA range: 50-150 and NI = 23. We achieved a maximum dose reduction of 10-22 times in the 1- to 12-month-old cranium in regard to the 2004 European guidelines for MDCT. A low-dose MDCT protocol that may be used as the first diagnostic imaging option in clinically selected patients with skull abnormalities. (orig.)

  11. Cystic Fibrosis: Are Volumetric Ultra-Low-Dose Expiratory CT Scans Sufficient for Monitoring Related Lung Disease?

    DEFF Research Database (Denmark)

    Loeve, Martine; Lequin, Maarten H; Bruijne, Marleen de

    2009-01-01

    that differences in scores were independent of score magnitude. Conclusion: In this pilot study, CT scores from end-expiratory and end-inspiratory CT match closely, suggesting that ultra-low-dose end-expiratory CT alone may be sufficient for monitoring CF-related lung disease. This would help reduce radiation dose......Purpose: To assess whether chest computed tomography (CT) scores from ultra-low-dose end-expiratory scans alone could suffice for assessment of all cystic fibrosis (CF)-related structural lung abnormalities. Materials and Methods: In this institutional review board–approved study, 20 patients...... with CF aged 6–20 years (eight males, 12 females) underwent low-dose end-inspiratory CT and ultra-low-dose end-expiratory CT. Informed consent was obtained. Scans were randomized and scored by using the Brody-II CT scoring system to assess bronchiectasis, airway wall thickening, mucus plugging...

  12. Low-Dose CT of the Paranasal Sinuses: Minimizing X-Ray Exposure with Spectral Shaping.

    Science.gov (United States)

    Wuest, Wolfgang; May, Matthias; Saake, Marc; Brand, Michael; Uder, Michael; Lell, Michael

    2016-11-01

    Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort. In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192x0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 × 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures. All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDIvol 1.2 mGy vs. 4.4 mGy, p image quality at a very low radiation exposure. • Spectral optimization (tin filtration) is beneficial to low-dose parasinus CT • Tin filtration at 100 kV yields sufficient image quality for pre-operative planning • Diagnostic parasinus CT can be performed with an effective dose <0.05 mSv.

  13. Abdominal and Pelvic CT

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    Full Text Available ... liver, kidney, pancreatic, uterine or ovarian abnormalities, the evaluation and diagnosis with MRI may be preferable over CT scanning. top of page Additional Information and Resources RTAnswers.org: Radiation Therapy for Bladder Cancer Radiation Therapy for Colorectal ...

  14. Abdominal and Pelvic CT

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    Full Text Available ... Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other ... another on an x-ray film or CT electronic image. In a conventional x-ray exam, a ...

  15. Abdominal and Pelvic CT

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    Full Text Available ... The teddy bear denotes child-specific content. Related Articles and Media Ultrasound - Abdomen X-ray (Radiography) - Lower GI Tract X-ray (Radiography) - Upper GI Tract Colorectal Cancer Images related to Computed Tomography (CT) - Abdomen and ...

  16. Abdominal and Pelvic CT

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    Full Text Available ... and Resources RTAnswers.org: Radiation Therapy for Bladder Cancer Radiation Therapy for Colorectal Cancer top of page This page was reviewed on ... with caption Pediatric Content Some imaging tests and treatments have special ... Cancer Images related to Computed Tomography (CT) - Abdomen and ...

  17. Abdominal and Pelvic CT

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    Full Text Available ... images or pictures of the inside of the body. The cross-sectional images generated during a CT scan can be reformatted ... at and passes through the part of the body being examined, recording an image on a special electronic image recording plate. Bones ...

  18. Abdominal and Pelvic CT

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    Full Text Available ... You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras ... and surgical biopsy. No radiation remains in a patient's body after a CT ... side effects. Risks There is always a slight chance of cancer ...

  19. Abdominal and Pelvic CT

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    Full Text Available ... can be performed if you have an implanted medical device of any kind, unlike MRI. CT imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the ...

  20. Abdominal and Pelvic CT

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    Full Text Available ... circumstances. For example, sometimes a parent wearing a lead shield may stay in the room with their child. However, the technologist will always be able to see, hear and speak with you through ... to wear a lead apron to minimize radiation exposure. After a CT ...

  1. Abdominal and Pelvic CT

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    Full Text Available ... Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other ... another on an x-ray film or CT electronic image. In a conventional x-ray exam, a ...

  2. Simple pulmonary eosinophilia detected at low-dose CT for lung cancer screening

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Kyung Nyeo; Bae, Kyung Soo; Kim, Ho Cheol [Gyeongsang National University Hospital, Jinju (Korea, Republic of)] (and others)

    2006-05-15

    The aim of this study was to evaluate the frequency, radiologic findings and clinical significance of the simple pulmonary eosinophilia (SPE) that was diagnosed among the asymptomatic patients who underwent low-dose CT scans for the early detection of lung cancer. From June 2003 to May 2005, 1,239 asymptomatic patients (1,275 examinations) who visited the health promotion center in our hospital and who underwent low-dose CT were enrolled in this study. SPE was defined as the presence of > 500 eosinophils per microliter of peripheral blood and the presence of abnormal parenchymal lesions such as nodules, airspace consolidation or areas of ground-glass attenuation (GGA) on CT, and there was spontaneous resolution or migration of the lesions on the follow-up examination. We analyzed the CT findings of SPE and we investigated the relationship between the occurrence of SPE and the season, smoking and the presence of parasite infestation. 36 patients were finally diagnosed as having SPE; this was 24% of the 153 patients who were diagnosed with parasite infestation and 2.8% of the total low-dose CT scans. These 36 patients consisted of 31 men and 5 women with a mean age 45.7 years. There was no significant relationship between SPE and the presence of parasite infestation, smoking or gender. Among the patients with peripheral blood eosinophilia, the eosinophil count was significantly higher in the patients with SPE than that in the patients without pulmonary infiltration ({rho} < 0.05). SPE more frequently occurred in winter and spring than in summer and autumn ({rho} < 0.05). The CT findings were single or multiple nodules in 18 patients, nodules and focal GGA in 9 patients and GGA only in 9 patients. Most of the nodules were less than 10 mm (88%, 49/56) in diameter and they showed an ill-defined margin (82%, n = 46); 30% of the nodules (n = 17) showed a halo around them. Simple pulmonary eosinophilia can be suggested as the cause if single or multiple ill-defined nodules

  3. Low-dose CT of the paranasal sinuses. Minimizing X-ray exposure with spectral shaping

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, Wolfgang [Friedrich-Alexander-University Erlangen-Nuremberg, Radiological Institute, Erlangen (Germany); Radiological Institute, Erlangen (Germany); May, Matthias; Saake, Marc; Brand, Michael; Uder, Michael; Lell, Michael [Friedrich-Alexander-University Erlangen-Nuremberg, Radiological Institute, Erlangen (Germany)

    2016-11-15

    Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort. In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192 x 0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 x 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures. All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDI{sub vol} 1.2 mGy vs. 4.4 mGy, p < 0.001). Spectral optimization (tin filtration at 100 kV) allows for visualization of the paranasal sinus with sufficient image quality at a very low radiation exposure. (orig.)

  4. Automated segmentation of cardiac visceral fat in low-dose non-contrast chest CT images

    Science.gov (United States)

    Xie, Yiting; Liang, Mingzhu; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2015-03-01

    Cardiac visceral fat was segmented from low-dose non-contrast chest CT images using a fully automated method. Cardiac visceral fat is defined as the fatty tissues surrounding the heart region, enclosed by the lungs and posterior to the sternum. It is measured by constraining the heart region with an Anatomy Label Map that contains robust segmentations of the lungs and other major organs and estimating the fatty tissue within this region. The algorithm was evaluated on 124 low-dose and 223 standard-dose non-contrast chest CT scans from two public datasets. Based on visual inspection, 343 cases had good cardiac visceral fat segmentation. For quantitative evaluation, manual markings of cardiac visceral fat regions were made in 3 image slices for 45 low-dose scans and the Dice similarity coefficient (DSC) was computed. The automated algorithm achieved an average DSC of 0.93. Cardiac visceral fat volume (CVFV), heart region volume (HRV) and their ratio were computed for each case. The correlation between cardiac visceral fat measurement and coronary artery and aortic calcification was also evaluated. Results indicated the automated algorithm for measuring cardiac visceral fat volume may be an alternative method to the traditional manual assessment of thoracic region fat content in the assessment of cardiovascular disease risk.

  5. Discriminative feature representation: an effective postprocessing solution to low dose CT imaging

    Science.gov (United States)

    Chen, Yang; Liu, Jin; Hu, Yining; Yang, Jian; Shi, Luyao; Shu, Huazhong; Gui, Zhiguo; Coatrieux, Gouenou; Luo, Limin

    2017-03-01

    This paper proposes a concise and effective approach termed discriminative feature representation (DFR) for low dose computerized tomography (LDCT) image processing, which is currently a challenging problem in medical imaging field. This DFR method assumes LDCT images as the superposition of desirable high dose CT (HDCT) 3D features and undesirable noise-artifact 3D features (the combined term of noise and artifact features induced by low dose scan protocols), and the decomposed HDCT features are used to provide the processed LDCT images with higher quality. The target HDCT features are solved via the DFR algorithm using a featured dictionary composed by atoms representing HDCT features and noise-artifact features. In this study, the featured dictionary is efficiently built using physical phantom images collected from the same CT scanner as the target clinical LDCT images to process. The proposed DFR method also has good robustness in parameter setting for different CT scanner types. This DFR method can be directly applied to process DICOM formatted LDCT images, and has good applicability to current CT systems. Comparative experiments with abdomen LDCT data validate the good performance of the proposed approach. This research was supported by National Natural Science Foundation under grants (81370040, 81530060), the Fundamental Research Funds for the Central Universities, and the Qing Lan Project in Jiangsu Province.

  6. CT appearances of abdominal tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.-K., E-mail: leewk33@hotmail.com [Department of Medical Imaging, St Vincent' s Hospital, University of Melbourne, Fitzroy, Victoria (Australia); Van Tonder, F.; Tartaglia, C.J.; Dagia, C. [Department of Medical Imaging, St Vincent' s Hospital, University of Melbourne, Fitzroy, Victoria (Australia); Cazzato, R.L. [Department of Radiology, Universita Campus Bio-Medico di Roma, Rome (Italy); Duddalwar, V.A. [Department of Radiology, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California (United States); Chang, S.D. [Department of Medical Imaging, Vancouver General Hospital, University of British Columbia, British Columbia (Canada)

    2012-06-15

    The purpose of this article is to review and illustrate the spectrum of computed tomography (CT) appearances of abdominal tuberculosis. Tuberculosis can affect any organ or tissue in the abdomen, and can be mistaken for other inflammatory or neoplastic conditions. The most common sites of tuberculosis in the abdomen include lymph nodes, genitourinary tract, peritoneal cavity and gastrointestinal tract. The liver, spleen, biliary tract, pancreas and adrenals are rarely affected, but are more likely in HIV-seropositive patients and in miliary tuberculosis. This article should alert the radiologist to consider abdominal tuberculosis in the correct clinical setting to ensure timely diagnosis and enable appropriate treatment.

  7. Computer-aided detection of early interstitial lung diseases using low-dose CT images

    Science.gov (United States)

    Park, Sang Cheol; Tan, Jun; Wang, Xingwei; Lederman, Dror; Leader, Joseph K.; Kim, Soo Hyung; Zheng, Bin

    2011-02-01

    This study aims to develop a new computer-aided detection (CAD) scheme to detect early interstitial lung disease (ILD) using low-dose computed tomography (CT) examinations. The CAD scheme classifies each pixel depicted on the segmented lung areas into positive or negative groups for ILD using a mesh-grid-based region growth method and a multi-feature-based artificial neural network (ANN). A genetic algorithm was applied to select optimal image features and the ANN structure. In testing each CT examination, only pixels selected by the mesh-grid region growth method were analyzed and classified by the ANN to improve computational efficiency. All unselected pixels were classified as negative for ILD. After classifying all pixels into the positive and negative groups, CAD computed a detection score based on the ratio of the number of positive pixels to all pixels in the segmented lung areas, which indicates the likelihood of the test case being positive for ILD. When applying to an independent testing dataset of 15 positive and 15 negative cases, the CAD scheme yielded the area under receiver operating characteristic curve (AUC = 0.884 ± 0.064) and 80.0% sensitivity at 85.7% specificity. The results demonstrated the feasibility of applying the CAD scheme to automatically detect early ILD using low-dose CT examinations.

  8. Automated detection and classification of interstitial lung diseases from low-dose CT images

    Science.gov (United States)

    Zheng, Bin; Leader, Joseph K.; Fuhrman, Carl R.; Sciurba, Frank C.; Gur, David

    2004-05-01

    We developed a computer-aided diagnosis (CAD) scheme to detect and quantitatively assess interstitial lung diseases (ILD) depicted on low-dose and multi-slice helical high-resolution computed tomography (CT) examinations. Eighteen CT cases acquired from patients who underwent routine low-dose whole-lung screening examinations for the detection of lung cancer were used to test the scheme. ILD was identified in all of these cases. The CAD scheme involves multiple steps to segment lung areas, identify suspicious ILD regions depicted on each CT slice, and generate volumetric ILD lesions by grouping and matching ILD regions detected on multiple adjacent slices. The scheme computes five "global" features for each identified ILD region, which include size (or volume), contrast, average local pixel value fluctuation, mean of stochastic fractal dimension, and geometric fractal dimension. Two sets of classification rules are applied to remove false-positive detections. The severity of ILD in each case was rated by one experienced chest radiologist into one of the three categories (mild, moderate, and severe). A distance-weighted k-nearest neighbor algorithm and round-robin validation method was applied to classify each testing case into one of the three categories of severity. In this experiment, the CAD scheme classified 78% (14 out of 18) cases into the same categories as rated by the radiologist.

  9. Computer-aided detection of early interstitial lung diseases using low-dose CT images

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Cheol; Kim, Soo Hyung [School of Electronics and Computer Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Tan, Jun; Wang Xingwei; Lederman, Dror; Leader, Joseph K; Zheng Bin, E-mail: zhengb@upmc.edu [Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213 (United States)

    2011-02-21

    This study aims to develop a new computer-aided detection (CAD) scheme to detect early interstitial lung disease (ILD) using low-dose computed tomography (CT) examinations. The CAD scheme classifies each pixel depicted on the segmented lung areas into positive or negative groups for ILD using a mesh-grid-based region growth method and a multi-feature-based artificial neural network (ANN). A genetic algorithm was applied to select optimal image features and the ANN structure. In testing each CT examination, only pixels selected by the mesh-grid region growth method were analyzed and classified by the ANN to improve computational efficiency. All unselected pixels were classified as negative for ILD. After classifying all pixels into the positive and negative groups, CAD computed a detection score based on the ratio of the number of positive pixels to all pixels in the segmented lung areas, which indicates the likelihood of the test case being positive for ILD. When applying to an independent testing dataset of 15 positive and 15 negative cases, the CAD scheme yielded the area under receiver operating characteristic curve (AUC = 0.884 {+-} 0.064) and 80.0% sensitivity at 85.7% specificity. The results demonstrated the feasibility of applying the CAD scheme to automatically detect early ILD using low-dose CT examinations.

  10. Low-dose fetal CT for evaluation of severe congenital skeletal anomalies: preliminary experience

    Energy Technology Data Exchange (ETDEWEB)

    Victoria, Teresa; Epelman, Monica; Johnson, Ann M.; Kramer, Sandra; Jaramillo, Diego [Children' s Hospital of Philadelphia, Diagnostic Imaging, Philadelphia, PA (United States); Bebbington, Michael [Children' s Hospital of Philadelphia, Center for Fetal Diagnosis and Treatment, Philadelphia, PA (United States); Wilson, R.D. [University of Calgary, Obstetrics and Gynecology, Calgary (Canada)

    2012-01-15

    Congenital skeletal abnormalities compose a heterogeneous and complex group of conditions that affect bone growth and development and result in various anomalies in shape and size of the skeleton. Prenatal sonographic diagnosis of these anomalies is challenging because of the relative rarity of each skeletal dysplasia, the multitude of differential diagnoses encountered when the bony abnormalities are identified, lack of precise molecular diagnosis and the fact that many of these disorders have overlapping features and marked phenotypic variability. The following review is a preliminary summary of our experience at the Children's Hospital of Philadelphia (CHOP) using low-dose fetal CT in the evaluation of severe fetal osseous abnormalities. (orig.)

  11. Ultra-low dose CT attenuation correction for PET/CT: analysis of sparse view data acquisition and reconstruction algorithms

    Science.gov (United States)

    Rui, Xue; Cheng, Lishui; Long, Yong; Fu, Lin; Alessio, Adam M.; Asma, Evren; Kinahan, Paul E.; De Man, Bruno

    2015-09-01

    For PET/CT systems, PET image reconstruction requires corresponding CT images for anatomical localization and attenuation correction. In the case of PET respiratory gating, multiple gated CT scans can offer phase-matched attenuation and motion correction, at the expense of increased radiation dose. We aim to minimize the dose of the CT scan, while preserving adequate image quality for the purpose of PET attenuation correction by introducing sparse view CT data acquisition. We investigated sparse view CT acquisition protocols resulting in ultra-low dose CT scans designed for PET attenuation correction. We analyzed the tradeoffs between the number of views and the integrated tube current per view for a given dose using CT and PET simulations of a 3D NCAT phantom with lesions inserted into liver and lung. We simulated seven CT acquisition protocols with {984, 328, 123, 41, 24, 12, 8} views per rotation at a gantry speed of 0.35 s. One standard dose and four ultra-low dose levels, namely, 0.35 mAs, 0.175 mAs, 0.0875 mAs, and 0.043 75 mAs, were investigated. Both the analytical Feldkamp, Davis and Kress (FDK) algorithm and the Model Based Iterative Reconstruction (MBIR) algorithm were used for CT image reconstruction. We also evaluated the impact of sinogram interpolation to estimate the missing projection measurements due to sparse view data acquisition. For MBIR, we used a penalized weighted least squares (PWLS) cost function with an approximate total-variation (TV) regularizing penalty function. We compared a tube pulsing mode and a continuous exposure mode for sparse view data acquisition. Global PET ensemble root-mean-squares-error (RMSE) and local ensemble lesion activity error were used as quantitative evaluation metrics for PET image quality. With sparse view sampling, it is possible to greatly reduce the CT scan dose when it is primarily used for PET attenuation correction with little or no measureable effect on the PET image. For the four ultra-low dose

  12. Ultra-low dose CT attenuation correction for PET/CT: analysis of sparse view data acquisition and reconstruction algorithms.

    Science.gov (United States)

    Rui, Xue; Cheng, Lishui; Long, Yong; Fu, Lin; Alessio, Adam M; Asma, Evren; Kinahan, Paul E; De Man, Bruno

    2015-10-07

    For PET/CT systems, PET image reconstruction requires corresponding CT images for anatomical localization and attenuation correction. In the case of PET respiratory gating, multiple gated CT scans can offer phase-matched attenuation and motion correction, at the expense of increased radiation dose. We aim to minimize the dose of the CT scan, while preserving adequate image quality for the purpose of PET attenuation correction by introducing sparse view CT data acquisition.We investigated sparse view CT acquisition protocols resulting in ultra-low dose CT scans designed for PET attenuation correction. We analyzed the tradeoffs between the number of views and the integrated tube current per view for a given dose using CT and PET simulations of a 3D NCAT phantom with lesions inserted into liver and lung. We simulated seven CT acquisition protocols with {984, 328, 123, 41, 24, 12, 8} views per rotation at a gantry speed of 0.35 s. One standard dose and four ultra-low dose levels, namely, 0.35 mAs, 0.175 mAs, 0.0875 mAs, and 0.043 75 mAs, were investigated. Both the analytical Feldkamp, Davis and Kress (FDK) algorithm and the Model Based Iterative Reconstruction (MBIR) algorithm were used for CT image reconstruction. We also evaluated the impact of sinogram interpolation to estimate the missing projection measurements due to sparse view data acquisition. For MBIR, we used a penalized weighted least squares (PWLS) cost function with an approximate total-variation (TV) regularizing penalty function. We compared a tube pulsing mode and a continuous exposure mode for sparse view data acquisition. Global PET ensemble root-mean-squares-error (RMSE) and local ensemble lesion activity error were used as quantitative evaluation metrics for PET image quality.With sparse view sampling, it is possible to greatly reduce the CT scan dose when it is primarily used for PET attenuation correction with little or no measureable effect on the PET image. For the four ultra-low dose levels

  13. Robust low-dose dynamic cerebral perfusion CT image restoration via coupled dictionary learning scheme.

    Science.gov (United States)

    Tian, Xiumei; Zeng, Dong; Zhang, Shanli; Huang, Jing; Zhang, Hua; He, Ji; Lu, Lijun; Xi, Weiwen; Ma, Jianhua; Bian, Zhaoying

    2016-11-22

    Dynamic cerebral perfusion x-ray computed tomography (PCT) imaging has been advocated to quantitatively and qualitatively assess hemodynamic parameters in the diagnosis of acute stroke or chronic cerebrovascular diseases. However, the associated radiation dose is a significant concern to patients due to its dynamic scan protocol. To address this issue, in this paper we propose an image restoration method by utilizing coupled dictionary learning (CDL) scheme to yield clinically acceptable PCT images with low-dose data acquisition. Specifically, in the present CDL scheme, the 2D background information from the average of the baseline time frames of low-dose unenhanced CT images and the 3D enhancement information from normal-dose sequential cerebral PCT images are exploited to train the dictionary atoms respectively. After getting the two trained dictionaries, we couple them to represent the desired PCT images as spatio-temporal prior in objective function construction. Finally, the low-dose dynamic cerebral PCT images are restored by using a general DL image processing. To get a robust solution, the objective function is solved by using a modified dictionary learning based image restoration algorithm. The experimental results on clinical data show that the present method can yield more accurate kinetic enhanced details and diagnostic hemodynamic parameter maps than the state-of-the-art methods.

  14. Development of low-dose protocols for thin-section CT assessment of cystic fibrosis in pediatric patients.

    LENUS (Irish Health Repository)

    O'Connor, Owen J

    2010-12-01

    To develop low-dose thin-section computed tomographic (CT) protocols for assessment of cystic fibrosis (CF) in pediatric patients and determine the clinical usefulness thereof compared with chest radiography.

  15. Low-dose 4D myocardial perfusion with x-ray micro-CT

    Science.gov (United States)

    Clark, D. P.; Badea, C. T.

    2017-03-01

    X-ray CT is widely used, both clinically and pre-clinically, for fast, high-resolution, anatomic imaging; however, compelling opportunities exist to expand its use in functional imaging applications. For instance, temporally-resolved CT data can detail cardiac motion and blood flow dynamics for one-stop cardiovascular CT imaging procedures. In previous work, we demonstrated efficient, low-dose projection acquisition and reconstruction strategies for cardiac micro-CT imaging and for multiple-injection micro-CT perfusion imaging. Here, we extend this previous work with regularization based on rank-sparse kernel regression and on filtration with the Karhunen-Loeve transform. Using a dual source, prospectively gated sampling strategy which produces an approximately uniform distribution of projections, we apply this revised algorithm to the assessment of both myocardial perfusion and cardiac functional metrics from the same set of projection data. We test the algorithm in simulations using a modified version of the MOBY mouse phantom which contains realistic perfusion and cardiac dynamics. The proposed algorithm reduces the reconstruction error by 81% relative to unregularized, algebraic reconstruction. The results confirm our ability to simultaneously solve for cardiac temporal motion and perfusion dynamics. In future work, we will apply the algorithm and sampling protocol to small animal cardiac studies.

  16. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    Science.gov (United States)

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  17. Median prior constrained TV algorithm for sparse view low-dose CT reconstruction.

    Science.gov (United States)

    Liu, Yi; Shangguan, Hong; Zhang, Quan; Zhu, Hongqing; Shu, Huazhong; Gui, Zhiguo

    2015-05-01

    It is known that lowering the X-ray tube current (mAs) or tube voltage (kVp) and simultaneously reducing the total number of X-ray views (sparse view) is an effective means to achieve low-dose in computed tomography (CT) scan. However, the associated image quality by the conventional filtered back-projection (FBP) usually degrades due to the excessive quantum noise. Although sparse-view CT reconstruction algorithm via total variation (TV), in the scanning protocol of reducing X-ray tube current, has been demonstrated to be able to result in significant radiation dose reduction while maintain image quality, noticeable patchy artifacts still exist in reconstructed images. In this study, to address the problem of patchy artifacts, we proposed a median prior constrained TV regularization to retain the image quality by introducing an auxiliary vector m in register with the object. Specifically, the approximate action of m is to draw, in each iteration, an object voxel toward its own local median, aiming to improve low-dose image quality with sparse-view projection measurements. Subsequently, an alternating optimization algorithm is adopted to optimize the associative objective function. We refer to the median prior constrained TV regularization as "TV_MP" for simplicity. Experimental results on digital phantoms and clinical phantom demonstrated that the proposed TV_MP with appropriate control parameters can not only ensure a higher signal to noise ratio (SNR) of the reconstructed image, but also its resolution compared with the original TV method.

  18. Evaluation of the effective dose and image quality of low-dose multi-detector CT for orthodontic treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Gi Chung; Han, Won Jeong; Kim, Eun Kyung [Department of Oral and Maxillofacial Radiology, School of Dentistry, Dankook University, Cheonan (Korea, Republic of)

    2010-03-15

    This study was designed to compare the effective doses from low-dose and standard-dose multi-detector CT (MDCT) scanning protocols and evaluate the image quality and the spatial resolution of the low-dose MDCT protocols for clinical use. 6-channel MDCT scanner (Siemens Medical System, Forschheim, Germany), was used for this study. Protocol of the standard-dose MDCT for the orthodontic analysis was 130 kV, 35 mAs, 1.25 mm slice width, 0.8 pitch. Those of the low-dose MDCT for orthodontic analysis and orthodontic surgery were 110 kV, 30 mAs, 1.25 mm slice width, 0.85 pitch and 110 kV, 45 mAs, 2.5 mm slice width, 0.85 pitch. Thermoluminescent dosimeters (TLDs) were placed at 31 sites throughout the levels of adult female ART head and neck phantom. Effective doses were calculated according to ICRP 1990 and 2007 recommendations. A formalin-fixed cadaver and AAPM CT performance phantom were scanned for the evaluation of subjective image quality and spatial resolution. Effective doses in {mu}Sv (E2007) were 699.1, 429.4 and 603.1 for standard-dose CT of orthodontic treatment, low-dose CT of orthodontic analysis, and low-dose CT of orthodontic surgery, respectively. The image quality from the low-dose protocol were not worse than those from the standard-dose protocol. The spatial resolutions of both standard-dose and low-dose CT images were acceptable. From the above results, it can be concluded that the low-dose MDCT protocol is preferable in obtaining CT images for orthodontic analysis and orthodontic surgery.

  19. Low-dose x-ray phase-contrast and absorption CT using equally sloped tomography

    Science.gov (United States)

    Fahimian, Benjamin P.; Mao, Yu; Cloetens, Peter; Miao, Jianwei

    2010-09-01

    Tomographic reconstruction from undersampled and noisy projections is often desirable in transmission CT modalities for purposes of low-dose tomography and fast acquisition imaging. However under such conditions, due to the violation of the Nyquist sampling criteria and the presence of noise, reconstructions with acceptable accuracy may not be possible. Recent experiments in transmission electron tomography and coherent diffraction microscopy have shown that the technique of equally sloped tomography (EST), an exact tomographic method utilizing an oversampling iterative Fourier-based reconstruction, provides more accurate image reconstructions when the number of projections is significantly undersampled relative to filtered back projection and algebraic iterative methods. Here we extend this technique by developing new reconstruction algorithms which allow for the incorporation of advanced mathematical regularization constraints, such as the nonlocal means total variational model, in a manner that is consistent with experimental projections. We then evaluate the resulting image quality of the developed algorithm through simulations and experiments at the European Synchrotron Radiation Facility on image quality phantoms using the x-ray absorption and phase contrast CT modalities. Both our simulation and experimental results have indicated that the method can reduce the number of projections by 60-75% in parallel beam modalities, while achieving comparable or better image quality than the conventional reconstructions. As large-scale and compact synchrotron radiation facilities are currently under rapid development worldwide, the implementation of low-dose x-ray absorption and phase-contrast CT can find broad applications in biology and medicine using these advanced x-ray sources.

  20. Low-dose x-ray phase-contrast and absorption CT using equally sloped tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fahimian, Benjamin P; Miao Jianwei [Department of Physics and Astronomy, and the California NanoSystems Institute, University of California, Los Angeles, CA 90095 (United States); Mao Yu [Department of Mathematics, University of California, Los Angeles, CA 90095 (United States); Cloetens, Peter, E-mail: miao@physics.ucla.ed, E-mail: fahimian@stanford.ed [European Synchrotron Radiation Facility, BP 220, 6 Rue Jules Horowitz, 38043 Grenoble Cedex (France)

    2010-09-21

    Tomographic reconstruction from undersampled and noisy projections is often desirable in transmission CT modalities for purposes of low-dose tomography and fast acquisition imaging. However under such conditions, due to the violation of the Nyquist sampling criteria and the presence of noise, reconstructions with acceptable accuracy may not be possible. Recent experiments in transmission electron tomography and coherent diffraction microscopy have shown that the technique of equally sloped tomography (EST), an exact tomographic method utilizing an oversampling iterative Fourier-based reconstruction, provides more accurate image reconstructions when the number of projections is significantly undersampled relative to filtered back projection and algebraic iterative methods. Here we extend this technique by developing new reconstruction algorithms which allow for the incorporation of advanced mathematical regularization constraints, such as the nonlocal means total variational model, in a manner that is consistent with experimental projections. We then evaluate the resulting image quality of the developed algorithm through simulations and experiments at the European Synchrotron Radiation Facility on image quality phantoms using the x-ray absorption and phase contrast CT modalities. Both our simulation and experimental results have indicated that the method can reduce the number of projections by 60-75% in parallel beam modalities, while achieving comparable or better image quality than the conventional reconstructions. As large-scale and compact synchrotron radiation facilities are currently under rapid development worldwide, the implementation of low-dose x-ray absorption and phase-contrast CT can find broad applications in biology and medicine using these advanced x-ray sources.

  1. Non-contrast CT at comparable dose to an abdominal radiograph in patients with acute renal colic; impact of iterative reconstruction on image quality and diagnostic performance.

    LENUS (Irish Health Repository)

    McLaughlin, P D

    2014-04-01

    The aim was to assess the performance of low-dose non-contrast CT of the urinary tract (LD-CT) acquired at radiation exposures close to that of abdominal radiography using adaptive statistical iterative reconstruction (ASiR).

  2. A framework of whole heart extracellular volume fraction estimation for low-dose cardiac CT images.

    Science.gov (United States)

    Chen, Xinjian; Nacif, Marcelo S; Liu, Songtao; Sibley, Christopher; Summers, Ronald M; Bluemke, David A; Yao, Jianhua

    2012-09-01

    Cardiac CT (CCT) is widely available and has been validated for the detection of focal myocardial scar using a delayed enhancement technique in this paper. CCT, however, has not been previously evaluated for quantification of diffuse myocardial fibrosis. In our investigation, we sought to evaluate the potential of low-dose CCT for the measurement of myocardial whole heart extracellular volume (ECV) fraction. ECV is altered under conditions of increased myocardial fibrosis. A framework consisting of three main steps was proposed for CCT whole heart ECV estimation. First, a shape-constrained graph cut (GC) method was proposed for myocardium and blood pool segmentation on postcontrast image. Second, the symmetric demons deformable registration method was applied to register precontrast to postcontrast images. So the correspondences between the voxels from precontrast to postcontrast images were established. Finally, the whole heart ECV value was computed. The proposed method was tested on 20 clinical low-dose CCT datasets with precontrast and postcontrast images. The preliminary results demonstrated the feasibility and efficiency of the proposed method.

  3. A framework of whole heart extracellular volume fraction estimation for low dose cardiac CT images

    Science.gov (United States)

    Chen, Xinjian; Summers, Ronald M.; Nacif, Marcelo Souto; Liu, Songtao; Bluemke, David A.; Yao, Jianhua

    2012-02-01

    Cardiac magnetic resonance imaging (CMRI) has been well validated and allows quantification of myocardial fibrosis in comparison to overall mass of the myocardium. Unfortunately, CMRI is relatively expensive and is contraindicated in patients with intracardiac devices. Cardiac CT (CCT) is widely available and has been validated for detection of scar and myocardial stress/rest perfusion. In this paper, we sought to evaluate the potential of low dose CCT for the measurement of myocardial whole heart extracellular volume (ECV) fraction. A novel framework was proposed for CCT whole heart ECV estimation, which consists of three main steps. First, a shape constrained graph cut (GC) method was proposed for myocardium and blood pool segmentation for post-contrast image. Second, the symmetric Demons deformable registrations method was applied to register pre-contrast to post-contrast images. Finally, the whole heart ECV value was computed. The proposed method was tested on 7 clinical low dose CCT datasets with pre-contrast and post-contrast images. The preliminary results demonstrated the feasibility and efficiency of the proposed method.

  4. Inter- and intrascanner variability of pulmonary nodule volumetry on low-dose 64-row CT : an anthropomorphic phantom study

    NARCIS (Netherlands)

    Xie, X.; Willemink, M. J.; Zhao, Y.; de Jong, P. A.; van Ooijen, P. M. A.; Oudkerk, M.; Greuter, M. J. W.; Vliegenthart, R.

    2013-01-01

    Objective: To assess inter- and intrascanner variability in volumetry of solid pulmonary nodules in an anthropomorphic thoracic phantom using low-dose CT. Methods: Five spherical solid artificial nodules [diameters 3, 5, 8, 10 and 12mm; CT density 1100 Hounsfield units (HU)] were randomly placed ins

  5. Effect of low-dose CT and iterative reconstruction on trabecular bone microstructure assessment

    Science.gov (United States)

    Kopp, Felix K.; Baum, Thomas; Nasirudin, Radin A.; Mei, Kai; Garcia, Eduardo G.; Burgkart, Rainer; Rummeny, Ernst J.; Bauer, Jan S.; Noël, Peter B.

    2016-03-01

    The trabecular bone microstructure is an important factor in the development of osteoporosis. It is well known that its deterioration is one effect when osteoporosis occurs. Previous research showed that the analysis of trabecular bone microstructure enables more precise diagnoses of osteoporosis compared to a sole measurement of the mineral density. Microstructure parameters are assessed on volumetric images of the bone acquired either with high-resolution magnetic resonance imaging, high-resolution peripheral quantitative computed tomography or high-resolution computed tomography (CT), with only CT being applicable to the spine, which is one of clinically most relevant fracture sites. However, due to the high radiation exposure for imaging the whole spine these measurements are not applicable in current clinical routine. In this work, twelve vertebrae from three different donors were scanned with standard and low radiation dose. Trabecular bone microstructure parameters were assessed for CT images reconstructed with statistical iterative reconstruction (SIR) and analytical filtered backprojection (FBP). The resulting structure parameters were correlated to the biomechanically determined fracture load of each vertebra. Microstructure parameters assessed for low-dose data reconstructed with SIR significantly correlated with fracture loads as well as parameters assessed for standard-dose data reconstructed with FBP. Ideal results were achieved with low to zero regularization strength yielding microstructure parameters not significantly different from those assessed for standard-dose FPB data. Moreover, in comparison to other approaches, superior noise-resolution trade-offs can be found with the proposed methods.

  6. [Lung cancer screening with low-dose thoracic CT-scan in the Somme area].

    Science.gov (United States)

    Leleu, O; Auquier, M; Carre, O; Chauffert, B; Dubreuil, A; Petigny, V; Trancart, B; Berna, P; Jounieaux, V

    2017-03-01

    This feasibility trial proposes to set up in the department of the Somme an annual screening for lung cancer with low-dose thoracic CT. It responds to the first objective of the third cancer plan and follows the publication of the results of the National Lung Screening Trial in 2011. The method of this study is to use the existing networks among and between healthcare professionals and the departmental cancer screening structure. The inclusion criteria will be those of the National Lung Screening Trial. Screening will be proposed by treating physicians and chest physicians. The CT-scan will be performed in radiological centers that adhere to the good practice charter for low radiation scanning. A copy of CT results will be sent to the departmental structure of cancer screening (ADEMA80) which will ensure traceability and will perform statistical analysis. The study received funding from the Agence régionale de santé de la Picardie and la ligue contre le cancer. The primary endpoints of this screening will be the number of cancers diagnosed and the survival of the patients. The follow-up of positive examinations, delays in management and the level of participation will also be assessed. Copyright © 2016 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  7. An adaptive nonlocal filtering for low-dose CT in both image and projection domains

    Directory of Open Access Journals (Sweden)

    Yingmei Wang

    2015-04-01

    Full Text Available An important problem in low-dose CT is the image quality degradation caused by photon starvation. There are a lot of algorithms in sinogram domain or image domain to solve this problem. In view of strong self-similarity contained in the special sinusoid-like strip data in the sinogram space, we propose a novel non-local filtering, whose average weights are related to both the image FBP (filtered backprojection reconstructed from restored sinogram data and the image directly FBP reconstructed from noisy sinogram data. In the process of sinogram restoration, we apply a non-local method with smoothness parameters adjusted adaptively to the variance of noisy sinogram data, which makes the method much effective for noise reduction in sinogram domain. Simulation experiments show that our proposed method by filtering in both image and projection domains has a better performance in noise reduction and details preservation in reconstructed images.

  8. Optimal image reconstruction for detection and characterization of small pulmonary nodules during low-dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, SayedMasoud; Cobbold, Richard S.C. [University of Toronto, Institute of Biomaterial and Biomedical Engineering, Toronto, ON (Canada); Mehrez, Hatem [Toshiba of Canada Ltd, Markham, ON (Canada); Paul, Narinder S. [University Health Network, Medical Imaging, Toronto General Hospital, Toronto, ON (Canada)

    2014-06-15

    To optimize the slice thickness/overlap parameters for image reconstruction and to study the effect of iterative reconstruction (IR) on detectability and characterization of small non-calcified pulmonary nodules during low-dose thoracic CT. Data was obtained from computer simulations, phantom, and patient CTs. Simulations and phantom CTs were performed with 9 nodules (5, 8, and 10 mm with 100, -630, and -800 HU). Patient data were based on 11 ground glass opacities (GGO) and 9 solid nodules. For each analysis the nodules were reconstructed with filtered back projection and IR algorithms using 10 different combinations of slice thickness/overlap (0.5-5 mm). The attenuation (CT) and the contrast to noise ratio (CNR) were measured. Spearman's coefficient was used to correlate the error in CT measurements and slice thickness. Paired Student's t test was used to measure the significance of the errors. CNR measurements: CNR increases with increasing slice thickness/overlap for large nodules and peaks at 4.0/2.0 mm for smaller ones. Use of IR increases the CNR of GGOs by 60 %. CT measurements: Increasing slice thickness/overlap above 3.0/1.5 mm results in decreased CT measurement accuracy. Optimal detection of small pulmonary nodules requires slice thickness/overlap of 4.0/2.0 mm. Slice thickness/overlap of 2.0/2.0 mm is required for optimal nodule characterization. IR improves conspicuity of small ground glass nodules through a significant increase in nodule CNR. (orig.)

  9. Heart region segmentation from low-dose CT scans: an anatomy based approach

    Science.gov (United States)

    Reeves, Anthony P.; Biancardi, Alberto M.; Yankelevitz, David F.; Cham, Matthew D.; Henschke, Claudia I.

    2012-02-01

    Cardiovascular disease is a leading cause of death in developed countries. The concurrent detection of heart diseases during low-dose whole-lung CT scans (LDCT), typically performed as part of a screening protocol, hinges on the accurate quantification of coronary calcification. The creation of fully automated methods is ideal as complete manual evaluation is imprecise, operator dependent, time consuming and thus costly. The technical challenges posed by LDCT scans in this context are mainly twofold. First, there is a high level image noise arising from the low radiation dose technique. Additionally, there is a variable amount of cardiac motion blurring due to the lack of electrocardiographic gating and the fact that heart rates differ between human subjects. As a consequence, the reliable segmentation of the heart, the first stage toward the implementation of morphologic heart abnormality detection, is also quite challenging. An automated computer method based on a sequential labeling of major organs and determination of anatomical landmarks has been evaluated on a public database of LDCT images. The novel algorithm builds from a robust segmentation of the bones and airways and embodies a stepwise refinement starting at the top of the lungs where image noise is at its lowest and where the carina provides a good calibration landmark. The segmentation is completed at the inferior wall of the heart where extensive image noise is accommodated. This method is based on the geometry of human anatomy and does not involve training through manual markings. Using visual inspection by an expert reader as a gold standard, the algorithm achieved successful heart and major vessel segmentation in 42 of 45 low-dose CT images. In the 3 remaining cases, the cardiac base was over segmented due to incorrect hemidiaphragm localization.

  10. Usefulness evaluation of low-dose for emphysema: Compared with high-resolution CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jeong [Dept. of Radiological Technology, Daejeon Health Institute of Technology, Daejeon (Korea, Republic of)

    2016-09-15

    The purpose of this study was to evaluate the usefulness of low-dose CT (LDCT) for emphysema compared with high-resolution CT (HRCT). Measurements of radiation dose and noise were repeated 3 times in same exposure condition which was similar with obtaining HRCT and LDCT images. We analysed reading results of 146 subjects. Six images per participants selected for emphysema grading. Emphysema was graded for all 6 zones on the left and right sides of the lungs by the consensus reading of two chest radiologists using a 4-point scale. Between the HRCT and LDCT images, diagnostic differences and agreements for emphysema were analyzed by McNemar's and unweighted kappa tests, and radiation doses and noise by a Mann-Whitney U-test, using the SPSS 19.0 program. Radiation dose from HRCT was significantly higher than that of LDCT, but the noise was significantly lower in HRCT than in LDCT. Diagnostic agreement for emphysema between HRCT and LDCT images was excellent (k-value=0.88). Emphysema grading scores were not significantly different between HRCT and LDCT images for all six lung zones. Emphysema grading scores from LDCT images were significantly correlated with increased scores on HRCT images (r=0.599, p < 0.001). Considering the tradeoff between radiation dose and image noise, LDCT could be used as the gold standard method instead of HRCT for emphysema detection and grading.

  11. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy

    Science.gov (United States)

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-01

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  12. Abdominal plain film in patients admitted with clinical suspicion of renal colic: should it be replaced by low-dose computed tomography?

    Science.gov (United States)

    Poletti, Pierre-Alexandre; Platon, Alexandra; Rutschmann, Olivier T; Verdun, Francis R; Schmidlin, Franz R; Iselin, Christophe E; Vermeulen, Bernard; Sarasin, François P; Buhler, Léo H; Becker, Christoph D

    2006-01-01

    To evaluate a low-dose abdominal computed tomography (LDCT) protocol, delivering a radiation dose close to that delivered by an abdominal plain film (APF), in patients with a clinical suspicion of renal colic. A total of 139 patients for whom an APF was requested for suspicion of renal colic were randomized into two groups. The patients in group 1 (n = 68) underwent an admission LDCT scan delivering a 2.1-mSv radiation dose to women and 1.6 mSv to men, instead of the APF. Patients in group 2 (n = 71) underwent an APF. Clinical and radiologic follow-up data were obtained for each patient. The number of additional abdominal ultrasound and CT scans performed to reach a confident final diagnosis and determine the proper treatment was compared between the two groups. A mean effective radiation dose was obtained in each group. Of the 68 patients in group 1 (LDCT), 10 (15%) underwent ultrasonography, 9 (13%) conventional abdominal CT, and 2 (3%) both. In group 2 (APF), the corresponding percentages were 27% (19 of 71), 28% (20 of 71), and 23% (16 of 71). Of the 68 patients in group 1, 47 (69%) did not require any additional examinations compared with 16 (23%) of the 71 patients in group 2 (P < 0.0001). The mean effective dose was 3.5 and 6.9 mSv in groups 1 and 2, respectively (P < 0.0001). In patients with suspicion of renal colic, replacing the admission APF with our LDCT protocol will significantly reduce the need for additional CT or ultrasonography. Also, our LDCT protocol decreases by almost 50% the mean radiation dose per patient.

  13. Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT

    Science.gov (United States)

    Liu, Hui; Chan, Chung; Grobshtein, Yariv; Ma, Tianyu; Liu, Yaqiang; Wang, Shi; Stacy, Mitchel R.; Sinusas, Albert J.; Liu, Chi

    2015-09-01

    Due to the limited spatial resolution, partial volume effect has been a major degrading factor on quantitative accuracy in emission tomography systems. This study aims to investigate the performance of several anatomical-based partial volume correction (PVC) methods for a dedicated cardiac SPECT/CT system (GE Discovery NM/CT 570c) with focused field-of-view over a clinically relevant range of high and low count levels for two different radiotracer distributions. These PVC methods include perturbation geometry transfer matrix (pGTM), pGTM followed by multi-target correction (MTC), pGTM with known concentration in blood pool, the former followed by MTC and our newly proposed methods, which perform the MTC method iteratively, where the mean values in all regions are estimated and updated by the MTC-corrected images each time in the iterative process. The NCAT phantom was simulated for cardiovascular imaging with 99mTc-tetrofosmin, a myocardial perfusion agent, and 99mTc-red blood cell (RBC), a pure intravascular imaging agent. Images were acquired at six different count levels to investigate the performance of PVC methods in both high and low count levels for low-dose applications. We performed two large animal in vivo cardiac imaging experiments following injection of 99mTc-RBC for evaluation of intramyocardial blood volume (IMBV). The simulation results showed our proposed iterative methods provide superior performance than other existing PVC methods in terms of image quality, quantitative accuracy, and reproducibility (standard deviation), particularly for low-count data. The iterative approaches are robust for both 99mTc-tetrofosmin perfusion imaging and 99mTc-RBC imaging of IMBV and blood pool activity even at low count levels. The animal study results indicated the effectiveness of PVC to correct the overestimation of IMBV due to blood pool contamination. In conclusion, the iterative PVC methods can achieve more accurate quantification, particularly for low

  14. Developing low-dose C-arm CT imaging for temporomandibular joint (TMJ) disorder in interventional radiology

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaowei; Cahill, Anne Marie [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Felice, Marc [University of Pennsylvania, Environmental Health and Radiation Safety, Philadelphia, PA (United States); Johnson, Laura [Computed Tomography Division, Siemens Healthcare Sector, Shanghai (China); Sarmiento, Marily [Siemens Medical Solutions, Angiography and X-ray Division, Hoffman Estates, IL (United States)

    2011-04-15

    Manufacturers have provided C-arm CT imaging technologies for applications in interventional radiology in recent years. However, clinical imaging protocols and radiation doses have not been well studied or reported. The purpose of this study is to develop low-dose settings for clinically acceptable CT imaging of temporomandibular joint in interventional radiology suites, using a C-arm imaging angiography system. CT scans were performed with a flat-panel digital C-arm angiographic system on a 5-year-old anthropomorphic phantom. The CTDI was determined for various rotation times, dose settings and Cu filter selections. The CTDI values were compared with those of conventional low-dose CT for the same phantom. The effectiveness of using Cu filters to reduce dose was also investigated. Images were reviewed by a senior radiologist for clinical acceptance. The manufacturer's default setting gave an equivalent CTDI of 4.8 mGy. Optimizing the dose settings and adding copper filtration reduced the radiation dose by 94%. This represents a 50% reduction from conventional CT. Use of Cu filters and low-dose settings significantly reduced radiation dose from that of standard settings. This phantom study process successfully guided the clinical implementation of low-dose studies for all ages at our institution. (orig.)

  15. Early interim FDG PET/CT prediction of treatment response and prognosis in pediatric Hodgkin disease - added value of low-dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Ilivitzki, Anat [Rambam Health Care Campus, Department of Diagnostic Imaging, Haifa (Israel); Rambam Health Care Campus, Department of Pediatric Radiology, Haifa (Israel); Radan, Lea; Israel, Ora [Rambam Health Care Campus, Department of Nuclear Medicine, Haifa (Israel); Ben-Arush, Miriam; Ben-Barak, Ayelet [Rambam Health Care Campus, Department of Pediatric Oncology, Haifa (Israel)

    2013-01-15

    Interim 18F-FDG PET helps predict outcome and tailor treatment in adults with Hodgkin disease (HD). The purpose of this study was to assess predictive values of interim 18F-FDG PET/CT in children with HD and to define the potential added value to interim PET of low-dose CT. Children were prospectively enrolled August 2002-April 2007. PET/low-dose CT was performed at staging, after 2 cycles, at the end of treatment and during follow-up (mean 45 months). Treatment was unchanged regardless of interim results. PET and low-dose CT were read independently. Of 34 enrolled children (ages 3-17 years), 27 achieved complete response, 4 had progressive disease and 3 had relapse. Interim PET alone had positive and negative predictive values of 67% and 89%, respectively. Interim low-dose CT alone had positive and negative predictive values of 35% and 100%, respectively. Interim PET/CT had positive and negative predictive values of 75% and 96%, respectively. Early interim PET/CT was a good predictor of outcome. Integrated PET and low-dose CT improved the predictive value in children with HD. (orig.)

  16. Segmentation of the whole breast from low-dose chest CT images

    Science.gov (United States)

    Liu, Shuang; Salvatore, Mary; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2015-03-01

    The segmentation of whole breast serves as the first step towards automated breast lesion detection. It is also necessary for automatically assessing the breast density, which is considered to be an important risk factor for breast cancer. In this paper we present a fully automated algorithm to segment the whole breast in low-dose chest CT images (LDCT), which has been recommended as an annual lung cancer screening test. The automated whole breast segmentation and potential breast density readings as well as lesion detection in LDCT will provide useful information for women who have received LDCT screening, especially the ones who have not undergone mammographic screening, by providing them additional risk indicators for breast cancer with no additional radiation exposure. The two main challenges to be addressed are significant range of variations in terms of the shape and location of the breast in LDCT and the separation of pectoral muscles from the glandular tissues. The presented algorithm achieves robust whole breast segmentation using an anatomy directed rule-based method. The evaluation is performed on 20 LDCT scans by comparing the segmentation with ground truth manually annotated by a radiologist on one axial slice and two sagittal slices for each scan. The resulting average Dice coefficient is 0.880 with a standard deviation of 0.058, demonstrating that the automated segmentation algorithm achieves results consistent with manual annotations of a radiologist.

  17. Automated segmentation of the pulmonary arteries in low-dose CT by vessel tracking

    CERN Document Server

    Wala, Jeremiah; Lee, Jaesung; Jirapatnakul, Artit; Biancardi, Alberto; Reeves, Anthony

    2011-01-01

    We present a fully automated method for top-down segmentation of the pulmonary arterial tree in low-dose thoracic CT images. The main basal pulmonary arteries are identified near the lung hilum by searching for candidate vessels adjacent to known airways, identified by our previously reported airway segmentation method. Model cylinders are iteratively fit to the vessels to track them into the lungs. Vessel bifurcations are detected by measuring the rate of change of vessel radii, and child vessels are segmented by initiating new trackers at bifurcation points. Validation is accomplished using our novel sparse surface (SS) evaluation metric. The SS metric was designed to quantify the magnitude of the segmentation error per vessel while significantly decreasing the manual marking burden for the human user. A total of 210 arteries and 205 veins were manually marked across seven test cases. 134/210 arteries were correctly segmented, with a specificity for arteries of 90%, and average segmentation error of 0.15 mm...

  18. Low-dose lung cancer screening with photon-counting CT: a feasibility study

    Science.gov (United States)

    Symons, Rolf; Cork, Tyler E.; Sahbaee, Pooyan; Fuld, Matthew K.; Kappler, Steffen; Folio, Les R.; Bluemke, David A.; Pourmorteza, Amir

    2017-01-01

    To evaluate the feasibility of using a whole-body photon-counting detector (PCD) CT scanner for low-dose lung cancer screening compared to a conventional energy integrating detector (EID) system. Radiation dose-matched EID and PCD scans of the COPDGene 2 phantom were acquired at different radiation dose levels (CTDIvol: 3.0, 1.5, and 0.75 mGy) and different tube voltages (120, 100, and 80 kVp). EID and PCD images were compared for quantitative Hounsfield unit (HU) accuracy, noise levels, and contrast-to-noise ratios (CNR) for detection of ground-glass nodules (GGN) and emphysema. The PCD HU accuracy was better than EID for water at all scan parameters. PCD HU stability for lung, GGN and emphysema regions were superior to EID and PCD attenuation values were more reproducible than EID for all scan parameters (all P  lung, GGN and emphysema ROIs changed significantly for EID with decreasing dose (all P  lung, ground-glass, and emphysema-equivalent foams at lower radiation dose settings with better reproducibility than EID. Additionally, PCD showed up to 10% less noise, and 11% higher CNR at 0.75 mGy for both 100 and 80 kVp. PCD technology may help reduce radiation exposure in lung cancer screening while maintaining diagnostic quality.

  19. Quantification of pulmonary vessel diameter in low-dose CT images

    Science.gov (United States)

    Rudyanto, Rina D.; Ortiz de Solórzano, Carlos; Muñoz-Barrutia, Arrate

    2015-03-01

    Accurate quantification of vessel diameter in low-dose Computer Tomography (CT) images is important to study pulmonary diseases, in particular for the diagnosis of vascular diseases and the characterization of morphological vascular remodeling in Chronic Obstructive Pulmonary Disease (COPD). In this study, we objectively compare several vessel diameter estimation methods using a physical phantom. Five solid tubes of differing diameters (from 0.898 to 3.980 mm) were embedded in foam, simulating vessels in the lungs. To measure the diameters, we first extracted the vessels using either of two approaches: vessel enhancement using multi-scale Hessian matrix computation, or explicitly segmenting them using intensity threshold. We implemented six methods to quantify the diameter: three estimating diameter as a function of scale used to calculate the Hessian matrix; two calculating equivalent diameter from the crosssection area obtained by thresholding the intensity and vesselness response, respectively; and finally, estimating the diameter of the object using the Full Width Half Maximum (FWHM). We find that the accuracy of frequently used methods estimating vessel diameter from the multi-scale vesselness filter depends on the range and the number of scales used. Moreover, these methods still yield a significant error margin on the challenging estimation of the smallest diameter (on the order or below the size of the CT point spread function). Obviously, the performance of the thresholding-based methods depends on the value of the threshold. Finally, we observe that a simple adaptive thresholding approach can achieve a robust and accurate estimation of the smallest vessels diameter.

  20. CTA-enhanced perfusion CT: an original method to perform ultra-low-dose CTA-enhanced perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Elizabeth; Wintermark, Max [University of Virginia, Department of Radiology, Neuroradiology Division, Charlottesville, VA (United States)

    2014-11-15

    Utilizing CT angiography enhances image quality in PCT, thereby permitting acquisition at ultra-low dose. Dynamic CT acquisitions were obtained at 80 kVp with decreasing tube current-time product [milliamperes x seconds (mAs)] in patients suspected of ischemic stroke, with concurrent CTA of the cervical and intracranial arteries. By utilizing fast Fourier transformation, high spatial frequencies of CTA were combined with low spatial frequencies of PCT to create a virtual PCT dataset. The real and virtual PCT datasets with decreasing mAs were compared by assessing contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and noise and PCT values and by visual inspection of PCT parametric maps. Virtual PCT attained CNR and SNR three- to sevenfold superior to real PCT and noise reduction by a factor of 4-6 (p < 0.05). At 20 mAs, virtual PCT achieved diagnostic parametric maps, while the quality of real PCT maps was inadequate. At 10 mAs, both real and virtual PCT maps were nondiagnostic. Virtual PCT (but not real PCT) maps regained diagnostic quality at 10 mAs by applying 40 % adaptive statistical iterative reconstruction (ASIR) and improved further with 80 % ASIR. Our new method of creating virtual PCT by combining ultra-low-dose PCT with CTA information yields diagnostic perfusion parametric maps from PCT acquired at 20 or 10 mAs with 80 % ASIR. Effective dose is approximately 0.20 mSv, equivalent to two chest radiographs. (orig.)

  1. Evaluation of dose reduction and image quality in CT colonography: Comparison of low-dose CT with iterative reconstruction and routine-dose CT with filtered back projection

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Koichi [Kameda Medical Center, Department of Radiology, Kamogawa, Chiba (Japan); Jichi Medical University, Department of Radiology, Tochigi (Japan); National Cancer Center, Cancer Screening Technology Division, Research Center for Cancer Prevention and Screening, Tokyo (Japan); Fujiwara, Masanori; Mogi, Tomohiro; Iida, Nao [Kameda Medical Center Makuhari, Department of Radiology, Chiba (Japan); Kanazawa, Hidenori; Sugimoto, Hideharu [Jichi Medical University, Department of Radiology, Tochigi (Japan); Mitsushima, Toru [Kameda Medical Center Makuhari, Department of Gastroenterology, Chiba (Japan); Lefor, Alan T. [Jichi Medical University, Department of Surgery, Tochigi (Japan)

    2015-01-15

    To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the prone series (p < 0.01). Overall image quality and noise of low-dose CTC with iterative reconstruction were significantly improved compared to routine-dose CTC using filtered back projection. The lowest dose group had image quality comparable to routine-dose images. Low-dose CTC with iterative reconstruction reduces the radiation dose by 48.5 to 75.1 % without image quality degradation compared to routine-dose CTC with filtered back projection. (orig.)

  2. Low-dose CT pulmonary angiography on a 15-year-old CT scanner: a feasibility study

    Directory of Open Access Journals (Sweden)

    Moritz Kaup

    2016-12-01

    Full Text Available Background Computed tomography (CT low-dose (LD imaging is used to lower radiation exposure, especially in vascular imaging; in current literature, this is mostly on latest generation high-end CT systems. Purpose To evaluate the effects of reduced tube current on objective and subjective image quality of a 15-year-old 16-slice CT system for pulmonary angiography (CTPA. Material and Methods CTPA scans from 60 prospectively randomized patients (28 men, 32 women were examined in this study on a 15-year-old 16-slice CT scanner system. Standard CT (SD settings were 100 kV and 150 mAs, LD settings were 100 kV and 50 mAs. Attenuation of the pulmonary trunk, various anatomic landmarks, and image noise were quantitatively measured; contrast-to-noise ratios (CNR and signal-to-noise ratios (SNR were calculated. Three independent blinded radiologists subjectively rated each image series using a 5-point grading scale. Results CT dose index (CTDI in the LD series was 66.46% lower compared to the SD settings (2.49 ± 0.55 mGy versus 7.42 ± 1.17 mGy. Attenuation of the pulmonary trunk showed similar results for both series (SD 409.55 ± 91.04 HU; LD 380.43 HU ± 93.11 HU; P = 0.768. Subjective image analysis showed no significant differences between SD and LD settings regarding the suitability for detection of central and peripheral PE (central SD/LD, 4.88; intra-class correlation coefficients [ICC], 0.894/4.83; ICC, 0.745; peripheral SD/LD, 4.70; ICC, 0.943/4.57; ICC, 0.919; all P > 0.4. Conclusion The LD protocol, on a 15-year-old CT scanner system without current high-end hardware or post-processing tools, led to a dose reduction of approximately 67% with similar subjective image quality and delineation of central and peripheral pulmonary arteries.

  3. Segmentation of the sternum from low-dose chest CT images

    Science.gov (United States)

    Liu, Shuang; Xie, Yiting; Reeves, Anthony P.

    2015-03-01

    Segmentation of the sternum in medical images is of clinical significance as it frequently serves as a stable reference to image registration and segmentation of other organs in the chest region. In this paper we present a fully automated algorithm to segment the sternum in low-dose chest CT images (LDCT). The proposed algorithm first locates an axial seed slice and then segments the sternum cross section on the seed slice by matching a rectangle model. Furthermore, it tracks and segments the complete sternum in the cranial and caudal direction respectively through sequential axial slices starting from the seed slice. The cross section on each axial slice is segmented using score functions that are designed to have local maxima at the boundaries of the sternum. Finally, the sternal angle is localized. The algorithm is designed to be specifically robust with respect to cartilage calcifications and to accommodate the high noise levels encountered with LDCT images. Segmentation of 351 cases from public datasets was evaluated visually with only 1 failing to produce a usable segmentation. 87.2% of the 351 images have good segmentation and 12.5% have acceptable segmentation. The sternal body segmentation and the localization of the sternal angle and the vertical extents of the sternum were also evaluated quantitatively for 25 good cases and 25 acceptable cases. The overall weighted mean DC of 0.897 and weighted mean distance error of 2.88 mm demonstrate that the algorithm achieves encouraging performance in both segmenting the sternal body and localizing the sternal angle.

  4. A decrease in lung cancer mortality following the introduction of low-dose chest CT screening in Hitachi, Japan.

    Science.gov (United States)

    Nawa, Takeshi; Nakagawa, Tohru; Mizoue, Tetsuya; Kusano, Suzushi; Chonan, Tatsuya; Hayashihara, Kenji; Suito, Tetsushi; Endo, Katsuyuki

    2012-12-01

    Recent US clinical trial demonstrated that CT screening prevents lung cancer death among high risk individuals. However, it remains unclear whether wide implementation of low-dose CT screening for lung cancer can decrease mortality in the community. Among residents in Hitachi City (Japan), where nearly 40% of inhabitants aged 50-69 years were estimated to have participated in the screening at least once from 1998 through 2009, the trend of lung cancer mortality was described in relation to the timing of implementation of the CT screening. Cancer mortality data were obtained from regional cancer registry and standardized mortality ratio (SMR) of lung cancer was calculated for each 5-year period during 1995-2009. In both men and women aged 60 years or older, age-specific lung cancer mortality rates were generally lower during 2005-2009 as compared with those during 1995-2004. For combined men and women aged 50-79 years, SMR was nearly unity prior to or during introductory phase of CT screening and during early period of implementation; however, it was significantly decreased during 2005-2009, well after the implementation of CT screening, with SMR (95% confidence interval) being 0.76 (0.67-0.86). Results suggest that wide implementation of low-dose chest CT screening may decrease lung cancer mortality in the community 4-8 years after introduction of the screening.

  5. Automatic lobar segmentation for diseased lungs using an anatomy-based priority knowledge in low-dose CT images

    Science.gov (United States)

    Park, Sang Joon; Kim, Jung Im; Goo, Jin Mo; Lee, Doohee

    2014-03-01

    Lung lobar segmentation in CT images is a challenging tasks because of the limitations in image quality inherent to CT image acquisition, especially low-dose CT for clinical routine environment. Besides, complex anatomy and abnormal lesions in the lung parenchyma makes segmentation difficult because contrast in CT images are determined by the differential absorption of X-rays by neighboring structures, such as tissue, vessel or several pathological conditions. Thus, we attempted to develop a robust segmentation technique for normal and diseased lung parenchyma. The images were obtained with low-dose chest CT using soft reconstruction kernel (Sensation 16, Siemens, Germany). Our PC-based in-house software segmented bronchial trees and lungs with intensity adaptive region-growing technique. Then the horizontal and oblique fissures were detected by using eigenvalues-ratio of the Hessian matrix in the lung regions which were excluded from airways and vessels. To enhance and recover the faithful 3-D fissure plane, our proposed fissure enhancing scheme were applied to the images. After finishing above steps, for careful smoothening of fissure planes, 3-D rolling-ball algorithm in xyz planes were performed. Results show that success rate of our proposed scheme was achieved up to 89.5% in the diseased lung parenchyma.

  6. More than lung cancer: Automated analysis of low-dose screening CT scans

    NARCIS (Netherlands)

    Mets, O.M.

    2012-01-01

    Smoking is a major health care problem and is projected to cause over 8 million deaths per year worldwide in the coming decades. To reduce lung cancer mortality in heavy smokers, several randomized screening trials were initiated in the past years using screening with low-dose Computed Tomography

  7. Evaluation of chronic infectious interstitial pulmonary disease in children by low-dose CT-guided transthoracic lung biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Heyer, Christoph M.; Lemburg, Stefan P.; Kagel, Thomas; Nicolas, Volkmar [Ruhr-University of Bochum, Institute of Diagnostic Radiology, Interventional Radiology and Nuclear Medicine, BG Clinics Bergmannsheil, Bochum (Germany); Mueller, Klaus-Michael [Ruhr-University of Bochum, Institute of Pathology, BG Clinics Bergmannsheil, Bochum (Germany); Nuesslein, Thomas G.; Rieger, Christian H.L. [Ruhr-University of Bochum, Pediatric Hospital, Bochum (Germany)

    2005-07-01

    Children with chronic infectious interstitial lung disease often have to undergo open lung biopsy to establish a final diagnosis. Open lung biopsy is an invasive procedure with major potential complications. Transthoracic lung biopsy (TLB) guided by computed tomography (CT) is a less-invasive well-established procedure in adults. Detailing the role of low-dose CT-guided TLB in the enhanced diagnosis of chronic lung diseases related to infection in children. A group of 11 children (age 8 months to 16 years) underwent CT-guided TLB with a 20-gauge biopsy device. All investigations were done under general anaesthesia on a multidetector CT scanner (SOMATOM Volume Zoom, Siemens, Erlangen, Germany) using a low-dose protocol (single slices, 120 kV, 20 mAs). Specimens were processed by histopathological, bacteriological, and virological techniques. All biopsies were performed without major complications; one child developed a small pneumothorax that resolved spontaneously. A diagnosis could be obtained in 10 of the 11 patients. Biopsy specimens revealed chronic interstitial alveolitis in ten patients. In five patients Chlamydia pneumoniae PCR was positive, in three Mycoplasma pneumoniae PCR was positive, and in two Cytomegalovirus PCR was positive. The average effective dose was 0.83 mSv. Low-dose CT-guided TLB can be a helpful tool in investigating chronic infectious inflammatory processes in children with minimal radiation exposure. It should be considered prior to any open surgical procedure performed for biopsy alone. In our patient group no significant complication occurred. A disadvantage of the method is that it does not allow smaller airways and vessels to be assessed. (orig.)

  8. Central image archiving and managements system for multicenter clinical studies: Lessons from low-dose CT for appendicitis trial

    Energy Technology Data Exchange (ETDEWEB)

    Ko, You Sun; Lee, Kyong Joon; Lee, Kyoung Ho [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); and others

    2017-03-15

    This special report aimed to document our experiences in implementing the Central Imaging Archiving and Management System (CIAMS) for a multicenter clinical trial, Low-dose CT for Appendicitis Trial (LOCAT), supported by the Korean Society of Radiology and Radiology Imaging Network of Korea for Clinical Research. LOCAT was a randomized controlled trial to determine whether low-dose CT is non-inferior to standard-dose CT with respect to the negative appendectomy rate in patients aged from 15 to 44 years. Site investigators downloaded the CT images from the site picture archiving and communication system servers, and uploaded the anonymized images to the primary server. CIAMS administrators inspected the images routed to the secondary server by a cross-check against image submission worksheets provided by the site investigators. The secondary server was automatically synchronized to the tertiary backup server. Up to June 2016, 2715 patients from 20 sites participated in LOCAT for 30 months. A total of 2539 patients' images (93.5%, 2539/2715) were uploaded to the primary server, 2193 patients' worksheets (80.8%, 2193/2715) were submitted, and 2163 patients' data (79.7%, 2163/2715) were finally monitored. No data error occurred.

  9. Towards robust deconvolution of low-dose perfusion CT: sparse perfusion deconvolution using online dictionary learning.

    Science.gov (United States)

    Fang, Ruogu; Chen, Tsuhan; Sanelli, Pina C

    2013-05-01

    Computed tomography perfusion (CTP) is an important functional imaging modality in the evaluation of cerebrovascular diseases, particularly in acute stroke and vasospasm. However, the post-processed parametric maps of blood flow tend to be noisy, especially in low-dose CTP, due to the noisy contrast enhancement profile and the oscillatory nature of the results generated by the current computational methods. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow in CTP performed at low radiation dose. We first build a dictionary from high-dose perfusion maps using online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation on the low-dose CTP data. Our method is validated on clinical data of patients with normal and pathological CBF maps. The results show that we achieve superior performance than existing methods, and potentially improve the differentiation between normal and ischemic tissue in the brain.

  10. Cost-effectiveness of the Introduction of Low-dose CT Screening in Japanese Smokers Aged 55 to 74 Years Old

    OpenAIRE

    Tabata, Hiroki; Akita, Tomoyuki; Matsuura, Akiko; Kaishima, Terumi; Matsuoka, Toshihiko; Ohisa, Masayuki; Awai, Kazuo; Tanaka, Junko

    2014-01-01

    The validity of low-dose CT screening for lung cancer in heavy smokers was supported by the results of National Lung Screening Trials (NLST) conducted in the U.S.A. The present study investigated the appropriateness of the introduction of low-dose CT screening for lung cancer in Japanese smokers aged between 55 and 74 years old, in terms of cost-effectiveness and age. To examine changes in the shift from conventional chest radiography (CR) to low-dose CT (LDCT) screening for lung cancer, we e...

  11. A clinical evaluation of total variation-Stokes image reconstruction strategy for low-dose CT imaging of the chest

    Science.gov (United States)

    Liu, Yan; Zhang, Hao; Moore, William; Bhattacharji, Priya; Liang, Zhengrong

    2015-03-01

    One hundred "normal-dose" computed tomography (CT) studies of the chest (i.e., 1,160 projection views, 120kVp, 100mAs) data sets were acquired from the patients who were scheduled for lung biopsy at Stony Brook University Hospital under informed consent approved by our Institutional Review Board. To mimic low-dose CT imaging scenario (i.e., sparse-view scan), sparse projection views were evenly extracted from the total 1,160 projections of each patient and the total radiation dose was reduced according to how many sparse views were selected. A standard filtered backprojection (FBP) algorithm was applied to the 1160 projections to produce reference images for comparison purpose. In the low-dose scenario, both the FBP and total variation-stokes (TVS) algorithms were applied to reconstruct the corresponding low-dose images. The reconstructed images were evaluated by an experienced thoracic radiologist against the reference images. Both the low-dose reconstructions and the reference images were displayed on a 4- megapixel monitor in soft tissue and lung windows. The images were graded by a five-point scale from 0 to 4 (0, nondiagnostic; 1, severe artifact with low confidence; 2, moderate artifact or moderate diagnostic confidences; 3, mild artifact or high confidence; 4, well depicted without artifacts). Quantitative evaluation measurements such as standard deviations for different tissue types and universal quality index were also studied and reported for the results. The evaluation concluded that the TVS can reduce the view number from 1,160 to 580 with slightly lower scores as the reference, resulting in a dose reduction to close 50%.

  12. 从RSNA2012看CT 低剂量技术的发展%Low Dose CT Technology-2012 SNA eview

    Institute of Scientific and Technical Information of China (English)

    张挽时

    2013-01-01

    本文回顾了刚刚结束的第98 届北美放射学会年会(RSNA2012)上关于CT 低剂量研究和临床的新进展.这些新技术包括各种迭代重建软件,更新型探测器等的推出,大幅度降低患者的辐射剂量,拓宽了CT 的临床应用,如全器官CT 灌注成像,大范围多期扫描等.合理使用低剂量ALARA 原则(As Low As Reasonably Achievable)同样适用于CT 检查.%This paper reviews the just-concluded 98th Annual Meeting of the Radiological Society of North America (RSNA2012) on CT low-dose studies and new clinical progress. These new technologies, including various iterative reconstruction software and updated type detectors, significantly reduce radiation dose patient received and broaden the clinical application of CT, such as whole-organ CT perfusion imaging, a wide range of multi-phase scan and so on. Rational use of low-dose ALARA principle (As Low As Reasonably Achievable) also applies to the CT examination.

  13. Low-dose CT for quantitative analysis in acute respiratory distress syndrome

    National Research Council Canada - National Science Library

    Vecchi, Vittoria; Langer, Thomas; Bellomi, Massimo; Rampinelli, Cristiano; Chung, Kevin K; Cancio, Leopoldo C; Gattinoni, Luciano; Batchinsky, Andriy I

    2013-01-01

    The clinical use of serial quantitative computed tomography (CT) to characterize lung disease and guide the optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS...

  14. Deep convolutional neural networks for automatic coronary calcium scoring in a screening study with low-dose chest CT

    Science.gov (United States)

    Lessmann, Nikolas; Išgum, Ivana; Setio, Arnaud A. A.; de Vos, Bob D.; Ciompi, Francesco; de Jong, Pim A.; Oudkerk, Matthjis; Mali, Willem P. Th. M.; Viergever, Max A.; van Ginneken, Bram

    2016-03-01

    The amount of calcifications in the coronary arteries is a powerful and independent predictor of cardiovascular events and is used to identify subjects at high risk who might benefit from preventive treatment. Routine quantification of coronary calcium scores can complement screening programs using low-dose chest CT, such as lung cancer screening. We present a system for automatic coronary calcium scoring based on deep convolutional neural networks (CNNs). The system uses three independently trained CNNs to estimate a bounding box around the heart. In this region of interest, connected components above 130 HU are considered candidates for coronary artery calcifications. To separate them from other high intensity lesions, classification of all extracted voxels is performed by feeding two-dimensional 50 mm × 50 mm patches from three orthogonal planes into three concurrent CNNs. The networks consist of three convolutional layers and one fully-connected layer with 256 neurons. In the experiments, 1028 non-contrast-enhanced and non-ECG-triggered low-dose chest CT scans were used. The network was trained on 797 scans. In the remaining 231 test scans, the method detected on average 194.3 mm3 of 199.8 mm3 coronary calcifications per scan (sensitivity 97.2 %) with an average false-positive volume of 10.3 mm3 . Subjects were assigned to one of five standard cardiovascular risk categories based on the Agatston score. Accuracy of risk category assignment was 84.4 % with a linearly weighted κ of 0.89. The proposed system can perform automatic coronary artery calcium scoring to identify subjects undergoing low-dose chest CT screening who are at risk of cardiovascular events with high accuracy.

  15. Ultra-low dose comprehensive cardiac CT imaging in a patient with acute myocarditis.

    Science.gov (United States)

    Tröbs, Monique; Brand, Michael; Achenbach, Stephan; Marwan, Mohamed

    2014-01-01

    The ability of contrast-enhanced CT to detect "late enhancement" in a fashion similar to magnetic resonance imaging has been previously reported. We report a case of acute myocarditis with coronary CT angiography as well as "late enhancement" imaging with ultra-low effective radiation dose.

  16. Reducing the radiation dose for low-dose CT of the paranasal sinuses using iterative reconstruction: Feasibility and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Bulla, Stefan, E-mail: stefan.bulla@uniklinik-freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Blanke, Philipp, E-mail: philipp.blanke@uniklinik.freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Hassepass, Frederike, E-mail: frederike.hassepass@uniklinik.freiburg.de [Department of Otorhinolaryngology – Head and Neck Surgery, University Hospital Freiburg, Killianstraße 5, 79106 Freiburg (Germany); Krauss, Tobias, E-mail: tobias.krauss@uniklinik.freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Winterer, Jan Thorsten, E-mail: jan.winterer@uniklinik.freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Breunig, Christine, E-mail: christine.breunig@uniklinik.freiburg.de [Department of Otorhinolaryngology – Head and Neck Surgery, University Hospital Freiburg, Killianstraße 5, 79106 Freiburg (Germany); Langer, Mathias, E-mail: mathias.langer@uniklinik.freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Pache, Gregor [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany)

    2012-09-15

    Purpose: To evaluate image quality of dose-reduced CT of the paranasal-sinus using an iterative reconstruction technique. Methods: In this study 80 patients (mean age: 46.9 ± 18 years) underwent CT of the paranasalsinus (Siemens Definition, Forchheim, Germany), with either standard settings (A: 120 kV, 60 mAs) reconstructed with conventional filtered back projection (FBP) or with tube current–time product lowering of 20%, 40% and 60% (B: 48 mAs, C: 36 mAs and D: 24 mAs) using iterative reconstruction (n = 20 each). Subjective image quality was independently assessed by four blinded observers using a semiquantitative five-point grading scale (1 = poor, 5 = excellent). Effective dose was calculated from the dose-length product. Mann–Whitney-U-test was used for statistical analysis. Results: Mean effective dose was 0.28 ± 0.03 mSv(A), 0.23 ± 0.02 mSv(B), 0.17 ± 0.02 mSv(C) and 0.11 ± 0.01 mSv(D) resulting in a maximum dose reduction of 60% with iterative reconstruction technique as compared to the standard low-dose CT. Best image quality was observed at 48 mAs (mean 4.8; p < 0.05), whereas standard low-dose CT (A) and maximum dose reduced scans (D) showed no significant difference in subjective image quality (mean 4.37 (A) and 4.31 (B); p = 0.72). Interobserver agreement was excellent (κ values 0.79–0.93). Conclusion: As compared to filtered back projection, the iterative reconstruction technique allows for significant dose reduction of up to 60% for paranasal-sinus CT without impairing the diagnostic image quality.

  17. Anatomical-based Partial Volume Correction for Low-dose Dedicated Cardiac SPECT/CT

    OpenAIRE

    Liu, Hui; Chan, Chung; Grobshtein, Yariv; Ma, Tianyu; Liu, Yaqiang; Wang, Shi; Stacy, Mitchel R.; Sinusas, Albert J.; Liu, Chi

    2015-01-01

    Due to the limited spatial resolution, partial volume effect (PVE) has been a major degrading factor on quantitative accuracy in emission tomography systems. This study aims to investigate the performance of several anatomical-based partial volume correction (PVC) methods for a dedicated cardiac SPECT/CT system (GE Discovery NM/CT 570c) with focused field-of-view (FOV) over a clinically relevant range of high and low count levels for two different radiotracer distributions. These PVC methods ...

  18. Impact of low-dose CT scan in dual timepoint investigations: a phantom study

    DEFF Research Database (Denmark)

    Micheelsen, M A; Jensen, Mikael

    2011-01-01

    with a CT image and also use the CT for attenuation correction. In any practical hospital setting, 1 hour is too long to occupy the scanner bed and a second CT procedure thus becomes necessary. This study tries to validate to what extent the dose/quality of the second CT scan can be lowered, without...... compromising attenuation correction, lesion detection and quantification. Using a standard NEMA phantom with the GE Discovery PET/CT scanner, taken in and out between scan sessions, we have tried to find the minimal CT dose necessary for the second scan while still reaching tissue activity quantification...... within predetermined error limits. For a hot sphere to background activity concentration ratio of 1:5, the average uptake (normalised by the time corrected input activity concentration) in a sphere of 6 cm3 was found to be 0.90 ± 0.08 for the standard scan, yielding a dose of 5.5 mGy, and 0.90 ± 0...

  19. Computed Tomography (CT) Perfusion in Abdominal Cancer

    DEFF Research Database (Denmark)

    Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten

    2013-01-01

    Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed...... table position. Advances in reconstruction algorithms make it possible to reduce the radiation dose for each examination to acceptable levels. Regarding abdominal imaging, CT perfusion is still considered a research tool, but several studies have proven it as a reliable non-invasive technique...... for assessment of vascularity. CT perfusion has also been used for tumor characterization, staging of disease, response evaluation of newer drugs targeted towards angiogenesis and as a method for early detection of recurrence after radiation and embolization. There are several software solutions available...

  20. Low-dose computed tomography scans with automatic exposure control for patients of different ages undergoing cardiac PET/CT and SPECT/CT.

    Science.gov (United States)

    Yang, Ching-Ching; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin; Liu, Shu-Hsin

    2017-06-01

    This study aimed to evaluate the efficacy of automatic exposure control (AEC) in order to optimize low-dose computed tomography (CT) protocols for patients of different ages undergoing cardiac PET/CT and single-photon emission computed tomography/computed tomography (SPECT/CT). One PET/CT and one SPECT/CT were used to acquire CT images for four anthropomorphic phantoms representative of 1-year-old, 5-year-old and 10-year-old children and an adult. For the hybrid systems investigated in this study, the radiation dose and image quality of cardiac CT scans performed with AEC activated depend mainly on the selection of a predefined image quality index. Multiple linear regression methods were used to analyse image data from anthropomorphic phantom studies to investigate the effects of body size and predefined image quality index on CT radiation dose in cardiac PET/CT and SPECT/CT scans. The regression relationships have a coefficient of determination larger than 0.9, indicating a good fit to the data. According to the regression models, low-dose protocols using the AEC technique were optimized for patients of different ages. In comparison with the standard protocol with AEC activated for adult cardiac examinations used in our clinical routine practice, the optimized paediatric protocols in PET/CT allow 32.2, 63.7 and 79.2% CT dose reductions for anthropomorphic phantoms simulating 10-year-old, 5-year-old and 1-year-old children, respectively. The corresponding results for cardiac SPECT/CT are 8.4, 51.5 and 72.7%. AEC is a practical way to reduce CT radiation dose in cardiac PET/CT and SPECT/CT, but the AEC settings should be determined properly for optimal effect. Our results show that AEC does not eliminate the need for paediatric protocols and CT examinations using the AEC technique should be optimized for paediatric patients to reduce the radiation dose as low as reasonably achievable.

  1. Investigating the low-dose limits of multidetector CT in lung nodule surveillance.

    Science.gov (United States)

    Paul, N S; Siewerdsen, J H; Patsios, D; Chung, T B

    2007-09-01

    The purpose of this study was to evaluate the factors limiting nodule detection in thoracic computed tomography (CT) and to determine whether prior knowledge of nodule size and attenuation, available from a baseline CT study, influences the minimum radiation dose at which nodule surveillance CT scans can be performed while maintaining current levels of nodule detectability. Multiple nodules varying in attenuation (-509 to + 110 HU) and diameter (1.6 to 9.5 mm) were layered in random and ordered sequences within 2 lung cylinders made of Rando lung material and suspended within a custom-built CT phantom. Multiple CT scans were performed at varying kVp (120, 100, and 80), mA (200, 150, 100, 50, 20, and 10), and beam collimation (5, 2.5, and 1.25 mm) on a four-row multidetector scanner (Lightspeed, General Electric, Milwaukee, WI) using 0.8 s gantry rotation. The corresponding range of radiation dose over which images were acquired was 0.3-26.4 mGy. Nine observers independently performed three specific tasks, namely: (1) To detect a 3.2 mm nodule of 23 HU; (2) To detect 3.2 mm nodules of varying attenuation (-509 to -154 HU); and (3) To detect nodules varying in size (1.6-9 mm) and attenuation (-509 to 110 HU). A two-alternative forced-choice test was used in order to determine the limits of nodule detection in terms of the proportion of correct responses (Pcorr, related to the area under the ROC curve) as a summary metric of observer performance. The radiation dose levels for detection of 99% of nodules in each task were as follows: Task 1 (1 mGy); Task 2 (5 mGy); and Task 3 (7 mGy). The corresponding interobserver confidence limits were 1, 5, and 10 mGy for Tasks 1, 2, and 3, respectively. There was a fivefold increase in the radiation dose required for detection of lower-density nodules (Tasks 1 to 2). Absence of prior knowledge of the nodule size and density (Task 3) corresponds to a significant increase in the minimum required radiation dose. Significant image

  2. Abdominal wall hernias: imaging with spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Stabile Ianora, A.A.; Midiri, M.; Vinci, R.; Rotondo, A.; Angelelli, G. [Department of Radiology, Bari University Hospital (Italy)

    2000-06-01

    Computed tomography is an accurate method of identifying the various types of abdominal wall hernias, especially if they are clinically occult, and of distinguishing them from other diseases such as hematomas, abscesses and neoplasia. In this study we examined the CT images of 94 patients affected by abdominal wall hernias observed over a period of 6 years. Computed tomography clearly demonstrates the anatomical site of the hernial sac, the content and any occlusive bowel complications due to incarceration or strangulation. Clinical diagnosis of external hernias is particularly difficult in obese patients or in those with laparotic scars. In these cases abdominal imaging is essential for a correct preoperative diagnosis and to determine the most effective treatment. (orig.)

  3. Automatic LV volume measurement in low dose multi-phase CT by shape tracking

    Science.gov (United States)

    von Berg, Jens; Begemann, Philipp; Stahmer, Felix; Adam, Gerhard; Lorenz, Cristian

    2006-03-01

    Functional assessment of cardiac ventricular function requires time consuming manual interaction. Some automated methods have been presented that predominantly used cardiac magnet resonance images. Here, an automatic shape tracking approach is followed to estimate left ventricular blood volume from multi-slice computed tomography image series acquired with retrospective ECG-gating. A deformable surface model method was chosen that utilized both shape and local appearance priors to determine the endocardial surface and to follow its motion through the cardiac cycle. Functional parameters like the ejection fraction could be calculated from the estimated shape deformation. A clinical validation was performed in a porcine model with 60 examinations on eight subjects. The functional parameters showed a good correlation with those determined by clinical experts using a commercially available semi-automatic short axes delineation tool. The correlation coefficient for the ejection fraction (EF) was 0.89. One quarter of these acquisitions were done with a low dose protocol. All of these degraded images could be processed well. Their correlation slightly decreases when compared to the normal dose cases (EF: 0.87 versus 0.88).

  4. Delayed enhancement imaging of myocardial viability: low-dose high-pitch CT versus MRI

    Energy Technology Data Exchange (ETDEWEB)

    Goetti, Robert; Feuchtner, Gudrun; Stolzmann, Paul; Donati, Olivio F.; Frauenfelder, Thomas; Leschka, Sebastian; Alkadhi, Hatem [University Hospital Zurich, Department of Radiology, Zurich (Switzerland); Wieser, Monika; Plass, Andre [University Hospital Zurich, Division of Cardiac and Vascular Surgery, Zurich (Switzerland)

    2011-10-15

    To evaluate the accuracy of high-pitch delayed enhancement (DE) CT for the assessment of myocardial viability with MRI as the reference standard. Twenty-four patients (mean age 66.9 {+-} 9.2 years) with coronary artery disease underwent DE imaging with 128-slice dual-source CT (prospective electrocardiography (ECG)-triggering) and MRI at 1.5 T. Two observers assessed DE transmurality per segment, and measured signal intensity (MRI) or attenuation (CT) in infarcted and healthy myocardium and noise in the left ventricular blood pool for calculating contrast-to-noise ratios (CNR). 75/408 (18.4%) segments in 18/24 patients (75.0%) showed DE in MRI, of which 28 segments in 10/24 (41.7%) patients were non-viable (scar tissue transmurality >50%). Sensitivity, specificity and accuracy of CT for diagnosis of non-viability were 60.7%, 96.8% and 94.4% per segment, and 90.0%, 92.9% and 91.7% per patient. CNR was significantly higher in MR (7.4 {+-} 3.0 vs. 4.6 {+-} 1.5; p = 0.018), and image noise significantly lower (11.6 {+-} 5.7 vs.15.0 {+-} 4.5; p = 0.019). Radiation dose of DECT was 0.89 {+-} 0.07 mSv. CTDE imaging in the high-pitch mode enables myocardial viability assessment at a low radiation dose and good accuracy compared with MR, although associated with a lower CNR and higher noise. (orig.)

  5. Low-dose CT for quantitative analysis in acute respiratory distress syndrome

    Science.gov (United States)

    2013-08-31

    Dipartimento di Anestesia, Rianimazione (Intensiva e Sub-intensiva) e Terapia del Dolore, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico di...boundaries were drawn automatically on each baseline image and manually on each CT image acquired on sheep with experimental ARDS. After processing each...led to differences in the manual selection of regions of interest within compared scans. In this regard, despite the slight change in image noise

  6. Prospectively gated axial CT coronary angiography: preliminary experiences with a novel low-dose technique

    Energy Technology Data Exchange (ETDEWEB)

    Klass, Oliver; Jeltsch, Martin; Feuerlein, Sebastian; Brunner, Horst; Brambs, Hans-Juergen; Hoffmann, Martin H.K. [University Hospital of Ulm, Department of Diagnostic and Interventional Radiology, Ulm (Germany); Nagel, Hans-Dieter [Philips Healthcare, Department of Science and Technology, Hamburg (Germany); Walker, Matthew J. [CT Clinical Science, Philips Healthcare, Cleveland, OH (United States)

    2009-04-15

    To assess image quality and radiation exposure with prospectively gated axial CT coronary angiography (PGA) compared to retrospectively gated helical techniques (RGH). Forty patients with suspected coronary artery disease (CAD) and a stable heart rate below 65 bpm underwent CT coronary angiography (CTCA) using a 64-channel CT system. The patient cohort consisted of 20 consecutive patients examined using a PGA technique and 20 patients examined using a standard RGH technique. Both groups were matched demographically according to age, gender, body mass index, and heart rate. For both groups, two independent observers assessed image quality for all coronary segments on an ordinal scale from 1 (nonassessable) to 5 (excellent quality). Image quality and radiation exposure were compared between patient groups. There were no significant differences in vessel-based image quality between the two groups (P > 0.05). Mean ({+-} SD) effective radiation exposure in the PGA group was 3.7 {+-} 0.8 mSv compared to 18.9 {+-} 3.8 mSv in the RGH group without ECG-based tube current modulation (P < 0.001). Preliminary experience shows PGA technique to be a promising approach for CTCA resulting in a substantial reduction in radiation exposure with image quality comparable to that of standard RGH technique. (orig.)

  7. Anxiety in Cancer Patients during 18F-FDG PET/CT Low Dose: A Comparison of Anxiety Levels before and after Imaging Studies

    Directory of Open Access Journals (Sweden)

    Ana Grilo

    2017-01-01

    Full Text Available Objective. Assessing the level of anxiety in oncology patients who underwent 18F-FDG PET/CT low dose scan and identifying the main reasons that generate anxiety. Material and Method. The study included 81 cancer patients submitted to the 18F-FDG PET/CT low dose scan. Patients filled in the Scan Experience Questionnaire and the State-Trait Anxiety Inventory (STAI before and after 18F-FDG PET/CT low dose scan. Results. Substantial levels of anxiety were detected both before and after 18F-FDG PET/CT low dose scan (STAI mean > 30, with a significant increase in the state of anxiety after scan performance (p<0.0001, Medianpre = 31.1, and Medianpos = 33.0. 18F-FDG PET/CT low dose results are the main cause of anxiety both before (79.1% and after (86.9% the scan. The information provided by staff both before and on the 18F-FDG PET/CT low dose day was classified mostly as completely understandable (70.5% and 75.3%, resp. and as very useful (70.5% and 72.6%, resp. and correlated positively with patients’ overall satisfaction with NM Department (rS=0.372, p=0.004 and rS=0.528, p = 0.000, resp., but not with anxiety levels. Conclusions. Patients perceive high levels of anxiety during the 18F-FDG PET/CT low dose scan and the concern with scan results was pointed out as the main factor for that emotional reaction.

  8. Anxiety in Cancer Patients during (18)F-FDG PET/CT Low Dose: A Comparison of Anxiety Levels before and after Imaging Studies.

    Science.gov (United States)

    Grilo, Ana; Vieira, Lina; Carolino, Elisabete; Oliveira, Cátia; Pacheco, Carolina; Castro, Maria; Alonso, Juan

    2017-01-01

    Objective. Assessing the level of anxiety in oncology patients who underwent (18)F-FDG PET/CT low dose scan and identifying the main reasons that generate anxiety. Material and Method. The study included 81 cancer patients submitted to the (18)F-FDG PET/CT low dose scan. Patients filled in the Scan Experience Questionnaire and the State-Trait Anxiety Inventory (STAI) before and after (18)F-FDG PET/CT low dose scan. Results. Substantial levels of anxiety were detected both before and after (18)F-FDG PET/CT low dose scan (STAI mean > 30), with a significant increase in the state of anxiety after scan performance (p < 0.0001, Medianpre = 31.1, and Medianpos = 33.0). (18)F-FDG PET/CT low dose results are the main cause of anxiety both before (79.1%) and after (86.9%) the scan. The information provided by staff both before and on the (18)F-FDG PET/CT low dose day was classified mostly as completely understandable (70.5% and 75.3%, resp.) and as very useful (70.5% and 72.6%, resp.) and correlated positively with patients' overall satisfaction with NM Department (rS = 0.372, p = 0.004 and rS = 0.528, p = 0.000, resp.), but not with anxiety levels. Conclusions. Patients perceive high levels of anxiety during the (18)F-FDG PET/CT low dose scan and the concern with scan results was pointed out as the main factor for that emotional reaction.

  9. Anxiety in Cancer Patients during 18F-FDG PET/CT Low Dose: A Comparison of Anxiety Levels before and after Imaging Studies

    Science.gov (United States)

    Vieira, Lina; Carolino, Elisabete; Oliveira, Cátia; Pacheco, Carolina; Castro, Maria; Alonso, Juan

    2017-01-01

    Objective. Assessing the level of anxiety in oncology patients who underwent 18F-FDG PET/CT low dose scan and identifying the main reasons that generate anxiety. Material and Method. The study included 81 cancer patients submitted to the 18F-FDG PET/CT low dose scan. Patients filled in the Scan Experience Questionnaire and the State-Trait Anxiety Inventory (STAI) before and after 18F-FDG PET/CT low dose scan. Results. Substantial levels of anxiety were detected both before and after 18F-FDG PET/CT low dose scan (STAI mean > 30), with a significant increase in the state of anxiety after scan performance (p < 0.0001, Medianpre = 31.1, and Medianpos = 33.0). 18F-FDG PET/CT low dose results are the main cause of anxiety both before (79.1%) and after (86.9%) the scan. The information provided by staff both before and on the 18F-FDG PET/CT low dose day was classified mostly as completely understandable (70.5% and 75.3%, resp.) and as very useful (70.5% and 72.6%, resp.) and correlated positively with patients' overall satisfaction with NM Department (rS = 0.372, p = 0.004 and rS = 0.528, p = 0.000, resp.), but not with anxiety levels. Conclusions. Patients perceive high levels of anxiety during the 18F-FDG PET/CT low dose scan and the concern with scan results was pointed out as the main factor for that emotional reaction. PMID:28392942

  10. Detection of lung cancer through low-dose CT screening (NELSON) : a prespecifi ed analysis of screening test performance and interval cancers

    NARCIS (Netherlands)

    Horeweg, Nanda; Scholten, Ernst Th; de Jong, Pim A.; van der Aalst, Carlijn M.; Weenink, Carla; Lammers, Jan-Willem J.; Nackaerts, Kristiaan; Vliegenthart, Rozemarijn; ten Haaf, Kevin; Yousaf-Khan, Uraujh A.; Heuvelmans, Marjolein A.; Thunnissen, Erik; Oudkerk, Matthijs; Mali, Willem; de Koning, Harry J.

    2014-01-01

    Background Low-dose CT screening is recommended for individuals at high risk of developing lung cancer. However, CT screening does not detect all lung cancers: some might be missed at screening, and others can develop in the interval between screens. The NELSON trial is a randomised trial to assess

  11. 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

  12. Lung cancer screening with low-dose helical CT in Korea: experiences at the Samsung Medical Center.

    Science.gov (United States)

    Chong, Semin; Lee, Kyung Soo; Chung, Myung Jin; Kim, Tae Sung; Kim, Hojoong; Kwon, O Jung; Choi, Yoon-Ho; Rhee, Chong H

    2005-06-01

    To determine overall detection rates of lung cancer by low-dose CT (LDCT) screening and to compare histopathologic and imaging differences of detected cancers between high- and low-risk groups, this study included 6,406 asymptomatic Korean adults with >or=45 yr of age who underwent LDCT for lung cancer screening. All were classified into high- (>or=20 pack-year smoking; 3,353) and low-risk (3,053; <20 pack-yr smoking and non-smokers) groups. We compared CT findings of detected cancers and detection rates between high- and low-risk. At initial CT, 35% (2,255 of 6,406) had at least one or more non-calcified nodule. Lung cancer detection rates were 0.36% (23 of 6,406). Twenty-one non-small cell lung cancers appeared as solid (n=14) or ground-glass opacity (GGO) (n=7) nodules. Cancer likelihood was higher in GGO nodules than in solid nodules (p<0.01). Fifteen of 23 cancers occurred in high-risk group and 8 in low-risk group (p=0.215). Therefore, LDCT screening help detect early stage of lung cancer in asymptomatic Korean population with detection rate of 0.36% on a population basis and may be useful for discovering early lung cancer in low-risk group as well as in high-risk group.

  13. Radiation Dose and Image Quality of Low-dose Protocol in Chest CT: Comparison of Standard-dose Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jeong [Occupational Lung Diseases Institute, KCOMWEL, Seoul (Korea, Republic of); Ahn, Bong Seon; Park, Young Sun [Department of Radiological Technology, Daejeon Health Science College, Daejeon (Korea, Republic of)

    2012-06-15

    The purpose of this study was to compare radiation dose and image quality between low-dose (LDP) and standard-dose protocol (SDP). LDP (120 kVp, 30 mAs, 2-mm thickness) and SDP (120 kVp, 180 mAs, 1.2-mm thickness) images obtained from 61 subjects were retrospectively evaluated at level of carina bifurcation, using multi-detector CT (Brilliance 16, Philips Medical Systems). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated at ascending aorta and infraspinatus muscle, from CT number and back-ground noise. Radiation dose from two protocols measured at 5-point using acrylic-phantom, and CT number and noise measured at 4-point using water-phantom. All statistical analysis were performed using SPSS 19.0 program. LDP images showed significantly more noise and a significantly lower SNR and CNR than did SDP images at ascending aorta and infraspinatus muscle. Noise, SNR and CNR were significantly correlated with body mass index (p<0.001). Radiation dose, SNR and CNR from phantom were significant differences between two protocols. LDP showed a significant reduction of radiation dose with a significant change in SNR and CNR compared with SDP. Therefore, exposure dose on LDP in clinical applications needs resetting highly more considering image quality.

  14. Performances of low-dose dual-energy CT in reducing artifacts from implanted metallic orthopedic devices

    Energy Technology Data Exchange (ETDEWEB)

    Filograna, Laura [Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Department of Radiological Sciences, Institute of Radiology, Rome (Italy); University of Zurich, Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, Zurich (Switzerland); Magarelli, Nicola; Leone, Antonio; Bonomo, Lorenzo [Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Department of Radiological Sciences, Institute of Radiology, Rome (Italy); De Waure, Chiara; Calabro, Giovanna Elisa [Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Research Centre for Health Technology Assessment, Department of Public Health, Section of Hygiene, Rome (Italy); Finkenstaedt, Tim [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Thali, Michael John [University of Zurich, Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, Zurich (Switzerland)

    2016-07-15

    The objective was to evaluate the performances of dose-reduced dual-energy computed tomography (DECT) in decreasing metallic artifacts from orthopedic devices compared with dose-neutral DECT, dose-neutral single-energy computed tomography (SECT), and dose-reduced SECT. Thirty implants in 20 consecutive cadavers underwent both SECT and DECT at three fixed CT dose indexes (CTDI): 20.0, 10.0, and 5.0 mGy. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV, and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. In each group, the image quality of the seven monoenergetic images and of the SECT image was assessed qualitatively and quantitatively by visually rating and by measuring the maximum streak artifact respectively. The comparison between SECT and OPTkeV evaluated overall within all groups showed a significant difference (p <0.001), with OPTkeV images providing better images. Comparing OPTkeV with the other DECT images, a significant difference was shown (p <0.001), with OPTkeV and 130-keV images providing the qualitatively best results. The OPTkeV images of 5.0-mGy acquisitions provided percentages of images with scores 1 and 2 of 36 % and 30 % respectively, compared with 0 % and 33.3 % of the corresponding SECT images of 10- and 20-mGy acquisitions. Moreover, DECT reconstructions at the OPTkeV of the low-dose group showed higher CT numbers than the SECT images of dose groups 1 and 2. This study demonstrates that low-dose DECT permits a reduction of artifacts due to metallic implants to be obtained in a similar manner to neutral-dose DECT and better than reduced or neutral-dose SECT. (orig.)

  15. Screening for lung cancer with low-dose computed tomography; Bronchialkarzinom-Screening mit Niedrigdosis-CT. Aktueller Stand

    Energy Technology Data Exchange (ETDEWEB)

    Diederich, S.; Wormanns, D.; Heindel, W. [Muenster Univ. (Germany). Inst. fuer Klinische Radiologie

    2001-03-01

    Lung cancer is the most common cause of death from malignancy. It is characterized by a favourable prognosis when treated in early stages and a poor prognosis in advanced stages. Populations at risk are relatively well defined, i.e. heavy smokers and workers exposed to asbestos and radon. Therefore, early detection using diagnostic techniques promises reduction of mortality from this tumor. Previous studies using chest radiography and sputum cytology were, however, disappointing due to poor sensitivity of these tests for early tumor stages. The new technique of low-dose computed tomography provides both high sensitivity for small tumors and a comfortable examination. As small benign pulmonary nodules are common reliable non-invasive diagnostic algorithms are required for classification of nodules. Preliminary studies using low-dose CT screening in smokers have provided promising results. Prior to a wide application of the technique in clinical routine more data are required as to inclusion criteria, examination intervals and the effect of screening on mortality reduction. (orig.) [German] Das Bronchialkarzinom ist der am haeufigsten zum Tode fuehrende maligne Tumor. Seine Prognose ist bei einer Therapie in fruehen Stadien relativ gut, in fortgeschrittenen Erkrankungsstadien dagegen ausgesprochen schlecht. Die Risikopopulationen sind gut charakterisiert, v.a. starke Raucher und Personen mit einer beruflichen Asbest- bzw. Radonexposition. Vor diesem Hintergrund erscheinen Frueherkennungsuntersuchungen mittels diagnostischer Verfahren sinnvoll, um die Sterblichkeit an diesem Tumor zu senken. Bisherige Erfahrungen mit Thoraxroentgenaufnahmen und Sputumuntersuchungen waren aufgrund der geringen Sensitivitaet der Verfahren fuer fruehe Tumorstadien jedoch enttaeuschend. Das relativ neue Verfahren der Niedrigdosis-Computertomographie des Thorax verbindet eine hohe Sensitivitaet fuer kleine Tumoren mit einer geringen Belastung der untersuchten Person. Wegen der Haeufigkeit

  16. [Development of transXend detector and its application to low dose exposure CT].

    Science.gov (United States)

    Kanno, Ikuo

    2013-01-01

    For practical energy-resolved computed tomography (CT), a transXend detector is proposed. The transXend detector consists of several segment detectors which are aligned along the direction of X-ray incidence. With response functions of segment detectors, the energy distribution of incident X-rays is obtained after unfolding process. Because the transXend detector measures X-rays as electric currents, it has no limit of counting rate: the number of X-rays in medical diagnosis ranges 10(6)-10(9)n/mm2/s, measuring energy of each X-ray is not practical at this stage. The operation principle and ways of application of the transXend detector are described. With defining narrow energy ranges in an unfolding process, effective atomic numbers are estimated with using white X-rays: the transXend detector can cut out quasi-monochromatic X-rays out of white X-rays. With the transXend detector with absorbers among the segment detectors, the directions of material thickness increment are shown different in the graph made of electric current ratios measured by the segment detectors. Using the current ratio graph, the thicknesses of the materials along the line X-rays passed are estimated. In other words, cancers marked by contrast agent can be detected with one transmission measurement, and possibly are measured and positioned by transmission measurements from two directions.

  17. A Model of Regularization Parameter Determination in Low-Dose X-Ray CT Reconstruction Based on Dictionary Learning

    Directory of Open Access Journals (Sweden)

    Cheng Zhang

    2015-01-01

    Full Text Available In recent years, X-ray computed tomography (CT is becoming widely used to reveal patient’s anatomical information. However, the side effect of radiation, relating to genetic or cancerous diseases, has caused great public concern. The problem is how to minimize radiation dose significantly while maintaining image quality. As a practical application of compressed sensing theory, one category of methods takes total variation (TV minimization as the sparse constraint, which makes it possible and effective to get a reconstruction image of high quality in the undersampling situation. On the other hand, a preliminary attempt of low-dose CT reconstruction based on dictionary learning seems to be another effective choice. But some critical parameters, such as the regularization parameter, cannot be determined by detecting datasets. In this paper, we propose a reweighted objective function that contributes to a numerical calculation model of the regularization parameter. A number of experiments demonstrate that this strategy performs well with better reconstruction images and saving of a large amount of time.

  18. CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Christe, Andreas, E-mail: andreas.christe@insel.ch [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); University Institute of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Inselspital, Freiburgstrasse 10, 3010 Bern (Switzerland); Lin, Margaret C., E-mail: mc_lin@hotmail.com [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); Yen, Andrew C., E-mail: acyen@ucsd.edu [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); Hallett, Rich L., E-mail: xraydoc97@yahoo.com [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); Roychoudhury, Kingshuk, E-mail: kingshuk@statucc.ie [Statistics Department, University College Cork, Cork (Ireland); Schmitzberger, Florian, E-mail: florians@stanford.edu [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); Fleischmann, Dominik, E-mail: d.fleischmann@stanford.edu [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); Leung, Ann N., E-mail: aleung@stanford.edu [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); Rubin, Geoffry D., E-mail: grubin@stanford.edu [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States); Vock, Peter, E-mail: peter.vock@insel.ch [University Institute of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Inselspital, Freiburgstrasse 10, 3010 Bern (Switzerland); Roos, Justus E., E-mail: justus.roos@stanford.edu [Department of Radiology, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305 (United States)

    2012-10-15

    Purpose: To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients. Materials and methods: Raw data of thoracic CT scans (64 × 0.75 mm, 120 kVp, 300 reference mAs) from 41 consecutive patients with clinical suspicion of pulmonary fungal infection were collected. In 32 patients fungal infection could be proven (median age of 55.5 years, range 35–83). A total of 267 cuboids showing CT patterns of fungal infection and 27 cubes having no disease were reconstructed at the original and 6 simulated tube currents of 100, 40, 30, 20, 10, and 5 reference mAs. Eight specific fungal CT patterns were analyzed by three radiologists: 76 ground glass opacities, 42 ground glass nodules, 51 mixed, part solid, part ground glass nodules, 36 solid nodules, 5 lobulated nodules, 6 spiculated nodules, 14 cavitary nodules, and 37 foci of air-space disease. The standard of reference was a consensus subjective interpretation by experts whom were not readers in the study. Results: The mean sensitivity and standard deviation for detecting pathological cuboids/disease using standard dose CT was 0.91 ± 0.07. Decreasing dose did not affect sensitivity significantly until the lowest dose level of 5 mAs (0.87 ± 0.10, p = 0.012). Nodular pattern discrimination was impaired below the dose level of 30 reference mAs: specificity for fungal ‘mixed nodules’ decreased significantly at 20, 10 and 5 reference mAs (p < 0.05). At lower dose levels, classification drifted from ‘solid’ to ‘mixed nodule’, although no lesion was missed. Conclusion: Our simulation data suggest that tube current levels can be reduced from 300 to 30 reference mAs without impairing the diagnostic information of specific CT patterns of pulmonary fungal infections.

  19. Effect of different reconstruction algorithms on computer-aided diagnosis (CAD) performance in ultra-low dose CT colonography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sun [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of); Kim, Se Hyung, E-mail: shkim7071@gmail.com [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of); Im, Jong Pil; Kim, Sang Gyun [Department of Internal Medicine, Seoul National University Hospital (Korea, Republic of); Shin, Cheong-il; Han, Joon Koo; Choi, Byung Ihn [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of)

    2015-04-15

    Highlights: •We assessed the effect of reconstruction algorithms on CAD in ultra-low dose CTC. •30 patients underwent ultra-low dose CTC using 120 and 100 kVp with 10 mAs. •CT was reconstructed with FBP, ASiR and Veo and then, we applied a CAD system. •Per-polyp sensitivity of CAD in ULD CT can be improved with the IR algorithms. •Despite of an increase in the number of FPs with IR, it was still acceptable. -- Abstract: Purpose: To assess the effect of different reconstruction algorithms on computer-aided diagnosis (CAD) performance in ultra-low-dose CT colonography (ULD CTC). Materials and methods: IRB approval and informed consents were obtained. Thirty prospectively enrolled patients underwent non-contrast CTC at 120 kVp/10 mAs in supine and 100 kVp/10 mAs in prone positions, followed by same-day colonoscopy. Images were reconstructed with filtered back projection (FBP), 80% adaptive statistical iterative reconstruction (ASIR80), and model-based iterative reconstruction (MBIR). A commercial CAD system was applied and per-polyp sensitivities and numbers of false-positives (FPs) were compared among algorithms. Results: Mean effective radiation dose of CTC was 1.02 mSv. Of 101 polyps detected and removed by colonoscopy, 61 polyps were detected on supine and on prone CTC datasets on consensus unblinded review, resulting in 122 visible polyps (32 polyps <6 mm, 52 6–9.9 mm, and 38 ≥ 10 mm). Per-polyp sensitivity of CAD for all polyps was highest with MBIR (56/122, 45.9%), followed by ASIR80 (54/122, 44.3%) and FBP (43/122, 35.2%), with significant differences between FBP and IR algorithms (P < 0.017). Per-polyp sensitivity for polyps ≥ 10 mm was also higher with MBIR (25/38, 65.8%) and ASIR80 (24/38, 63.2%) than with FBP (20/38, 58.8%), albeit without statistical significance (P > 0.017). Mean number of FPs was significantly different among algorithms (FBP, 1.4; ASIR, 2.1; MBIR, 2.4) (P = 0.011). Conclusion: Although the performance of stand-alone CAD

  20. Acute appendicitis: prospective evaluation of a diagnostic algorithm integrating ultrasound and low-dose CT to reduce the need of standard CT

    Energy Technology Data Exchange (ETDEWEB)

    Poletti, Pierre-Alexandre; Platon, Alexandra [University Hospital of Geneva, Department of Radiology, Geneva (Switzerland); University Hospital of Geneva, Emergency Center, Geneva (Switzerland); Perrot, Thomas de; Becker, Christoph D. [University Hospital of Geneva, Department of Radiology, Geneva (Switzerland); Sarasin, Francois; Rutschmann, Olivier [University Hospital of Geneva, Emergency Center, Geneva (Switzerland); Andereggen, Elisabeth [University Hospital of Geneva, Emergency Center, Geneva (Switzerland); University Hospital of Geneva, Department of Surgery, Geneva (Switzerland); Dupuis-Lozeron, Elise; Perneger, Thomas [University Hospital of Geneva, Division of Clinical Epidemiology, Geneva (Switzerland); Gervaz, Pascal [University Hospital of Geneva, Department of Surgery, Geneva (Switzerland)

    2011-12-15

    To evaluate an algorithm integrating ultrasound and low-dose unenhanced CT with oral contrast medium (LDCT) in the assessment of acute appendicitis, to reduce the need of conventional CT. Ultrasound was performed upon admission in 183 consecutive adult patients (111 women, 72 men, mean age 32) with suspicion of acute appendicitis and a BMI between 18.5 and 30 (step 1). No further examination was recommended when ultrasound was positive for appendicitis, negative with low clinical suspicion, or demonstrated an alternative diagnosis. All other patients underwent LDCT (30 mAs) (step 2). Standard intravenously enhanced CT (180 mAs) was performed after indeterminate LDCT (step 3). No further imaging was recommended after ultrasound in 84 (46%) patients; LDCT was obtained in 99 (54%). LDCT was positive or negative for appendicitis in 81 (82%) of these 99 patients, indeterminate in 18 (18%) who underwent standard CT. Eighty-six (47%) of the 183 patients had a surgically proven appendicitis. The sensitivity and specificity of the algorithm were 98.8% and 96.9%. The proposed algorithm achieved high sensitivity and specificity for detection of acute appendicitis, while reducing the need for standard CT and thus limiting exposition to radiation and to intravenous contrast media. (orig.)

  1. Acute appendicitis: prospective evaluation of a diagnostic algorithm integrating ultrasound and low-dose CT to reduce the need of standard CT.

    Science.gov (United States)

    Poletti, Pierre-Alexandre; Platon, Alexandra; De Perrot, Thomas; Sarasin, Francois; Andereggen, Elisabeth; Rutschmann, Olivier; Dupuis-Lozeron, Elise; Perneger, Thomas; Gervaz, Pascal; Becker, Christoph D

    2011-12-01

    To evaluate an algorithm integrating ultrasound and low-dose unenhanced CT with oral contrast medium (LDCT) in the assessment of acute appendicitis, to reduce the need of conventional CT. Ultrasound was performed upon admission in 183 consecutive adult patients (111 women, 72 men, mean age 32) with suspicion of acute appendicitis and a BMI between 18.5 and 30 (step 1). No further examination was recommended when ultrasound was positive for appendicitis, negative with low clinical suspicion, or demonstrated an alternative diagnosis. All other patients underwent LDCT (30 mAs) (step 2). Standard intravenously enhanced CT (180 mAs) was performed after indeterminate LDCT (step 3). No further imaging was recommended after ultrasound in 84 (46%) patients; LDCT was obtained in 99 (54%). LDCT was positive or negative for appendicitis in 81 (82%) of these 99 patients, indeterminate in 18 (18%) who underwent standard CT. Eighty-six (47%) of the 183 patients had a surgically proven appendicitis. The sensitivity and specificity of the algorithm were 98.8% and 96.9%. The proposed algorithm achieved high sensitivity and specificity for detection of acute appendicitis, while reducing the need for standard CT and thus limiting exposition to radiation and to intravenous contrast media.

  2. Low-dose CT screening in an Asian population with diverse risk for lung cancer: A retrospective cohort study

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Chin A. [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Lee, Kyung Soo [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Shin, Myung-Hee; Cho, Yun Yung [Sungkyunkwan University School of Medicine, Department of Social and Preventive Medicine, Seoul (Korea, Republic of); Choi, Yoon-Ho [Sungkyunkwan University School of Medicine, Center for Health Promotion, Seoul (Korea, Republic of); Kwon, O. Jung [Sungkyunkwan University School of Medicine, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Seoul (Korea, Republic of); Shin, Kyung Eun [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Kyung Hee University Hospital, Department of Diagnostic Radiology, Seoul (Korea, Republic of)

    2015-08-15

    To evaluate the performance of low-dose CT (LDCT) screening for lung cancer (LCA) detection in an Asian population with diverse risks for LCA. LCA screening was performed in 12,427 symptomless Asian subjects using either LDCT (5,771) or chest radiography (CXR) (6,656) in a non-trial setting. Subjects were divided into high-risk and non-high-risk groups. Data were collected on the number of patients with screening-detected LCAs and their survival in order to compare outcomes between LDCT and CXR screening with the stratification of risks considering age, sex and smoking status. In the non-high-risk group, a significant difference was observed for the detection of lung cancer (adjusted OR, 5.07; 95 % CI, 2.72-9.45) and survival (adjusted HR of LCA survival between LDCT vs. CXR group, 0.08; 95 % CI, 0.01-0.62). No difference in detection or survival of LCA was noticed in the high-risk group. LCAs in the non-high-risk group were predominantly adenocarcinomas (96 %), and more likely to be part-solid or non-solid compared with those in the high-risk group (p = 0.023). In the non-high-risk group, LDCT helps detect more LCAs and offers better survival than CXR screening, due to better detection of part solid or non-solid lung adenocarcinomas. (orig.)

  3. Small pulmonary nodules in baseline and incidence screening rounds of low-dose CT lung cancer screening.

    Science.gov (United States)

    Walter, Joan E; Heuvelmans, Marjolein A; Oudkerk, Matthijs

    2017-02-01

    Currently, lung cancer screening by low-dose computed tomography (LDCT) is widely recommended for high-risk individuals by US guidelines, but there still is an ongoing debate concerning respective recommendations for European countries. Nevertheless, the available data regarding pulmonary nodules released by lung cancer screening studies could improve future screening guidelines, as well as the clinical practice of incidentally detected pulmonary nodules on routine CT scans. Most lung cancer screening trials present results for baseline and incidence screening rounds separately, clustering pulmonary nodules initially found at baseline screening and newly detected pulmonary nodules after baseline screening together. This approach does not appreciate possible differences among pulmonary nodules detected at baseline and firstly detected at incidence screening rounds and is heavily influenced by methodological differences of the respective screening trials. This review intends to create a basis for assessing non-calcified pulmonary nodules detected during LDCT lung cancer screening in a more clinical relevant manner. The aim is to present data of non-calcified pulmonary baseline nodules and new non-calcified pulmonary incident nodules without clustering them together, thereby also simplifying translation to the clinical practice of incidentally detected pulmonary nodules. Small pulmonary nodules newly detected at incidence screening rounds of LDCT lung cancer screening may possess a greater lung cancer probability than pulmonary baseline nodules at a smaller size, which is essential for the development of new guidelines.

  4. Application of low dose radiation and low concentration contrast media in enhanced CT scans in children with congenital heart disease.

    Science.gov (United States)

    Liu, Zhimin; Song, Lei; Yu, Tong; Gao, Jun; Zhang, Qifeng; Jiang, Ling; Liu, Yong; Peng, Yun

    2016-09-01

    The aim of this study was to explore the feasibility of using low dose radiation and low concentration contrast media in enhanced CT examinations in children with congenital heart disease. Ninety patients with congenital heart disease were randomly divided into three groups of 30 patients each who underwent contrast-enhanced cardiac scans on a Discovery CT750 HD scanner. Group A received 270 mg I/mL iodixanol, and group B received 320 mg I/mL iodixanol contrast media and was scanned with prospective ECG triggering mode. Group C received 320 mg I/mL iodixanol and was scanned with conventional retrospective ECG gating mode. The same weight-based contrast injection protocol was used for all three groups. Images were reconstructed using a 30% adaptive statistical iterative reconstruction (ASIR) algorithm and a 50% ASIR in groups A and B and a 30% ASIR in group C. The subjective and objective image quality evaluations, diagnostic accuracies, radiation doses and amounts of contrast media in the three groups were measured and compared. All images in the three groups met the diagnostic requirements, with the same diagnostic accuracy and image quality scores greater than 3 in a 4-point scoring system. However, ventricular enhancement and the objective noise, signal-to-noise ratio, contrast-to-noise ratio and subjective image quality scores in group C were better than those in groups A and B (all Pconcentration contrast media can meet the diagnostic requirements for examining children with congenital heart disease while reducing the potential risk of radiation damage and contrast-induced nephropathy. © 2016 John Wiley & Sons Ltd.

  5. Occurrence and lung cancer probability of new solid nodules at incidence screening with low-dose CT : analysis of data from the randomised, controlled NELSON trial

    NARCIS (Netherlands)

    Walter, Joan E.; Heuvelmans, Marjolein A.; de Jong, Pim A.; Vliegenthart, Rozemarijn; van Ooijen, Peter M. A.; Peters, Robin B.; ten Haaf, Kevin; Yousaf-Khan, Uraujh; van der Aalst, Carlijn M.; de Bock, Geertruida H.; Mali, Willem; Groen, Harry J. M.; de Koning, Harry J.; Oudkerk, Matthijs

    2016-01-01

    Background US guidelines now recommend lung cancer screening with low-dose CT for high-risk individuals. Reports of new nodules after baseline screening have been scarce and are inconsistent because of differences in definitions used. We aimed to identify the occurrence of new solid nodules and thei

  6. Occurrence and lung cancer probability of new solid nodules at incidence screening with low-dose CT : analysis of data from the randomised, controlled NELSON trial

    NARCIS (Netherlands)

    Walter, Joan E.; Heuvelmans, Marjolein A.; de Jong, Pim A.; Vliegenthart, Rozemarijn; van Ooijen, Peter M. A.; Peters, Robin B.; ten Haaf, Kevin; Yousaf-Khan, Uraujh; van der Aalst, Carlijn M.; de Bock, Geertruida H.; Mali, Willem; Groen, Harry J. M.; de Koning, Harry J.; Oudkerk, Matthijs

    2016-01-01

    BACKGROUND: US guidelines now recommend lung cancer screening with low-dose CT for high-risk individuals. Reports of new nodules after baseline screening have been scarce and are inconsistent because of differences in definitions used. We aimed to identify the occurrence of new solid nodules and the

  7. Occurrence and lung cancer probability of new solid nodules at incidence screening with low-dose CT : analysis of data from the randomised, controlled NELSON trial

    NARCIS (Netherlands)

    Walter, Joan E.; Heuvelmans, Marjolein A.; de Jong, Pim A.; Vliegenthart, Rozemarijn; van Ooijen, Peter M A; Peters, Robin B.; ten Haaf, Kevin; Yousaf-Khan, Uraujh; van der Aalst, Carlijn M.; de Bock, Geertruida H.; Mali, Willem P Th M; Groen, Harry J M; de Koning, Harry J.; Oudkerk, Matthijs

    BACKGROUND: US guidelines now recommend lung cancer screening with low-dose CT for high-risk individuals. Reports of new nodules after baseline screening have been scarce and are inconsistent because of differences in definitions used. We aimed to identify the occurrence of new solid nodules and

  8. Assessment of pulmonary function using pixel indexes of multiple-slice spiral CT low-dose two-phase scanning in chronic obstructive pulmonary disease

    Institute of Scientific and Technical Information of China (English)

    张利华

    2012-01-01

    Objective To explore the values of pixel indexes (PI) with multiple-slice spiral CT low-dose two-phase scanning for assessing the pulmonary function in chronic obstructive pulmonary disease(COPD) . Methods Thirty-six patients with COPD (COPD group) and 30 healthy people(control group) underwent pulmonary

  9. Over-exposure correction in knee cone-beam CT imaging with automatic exposure control using a partial low dose scan

    Science.gov (United States)

    Choi, Jang-Hwan; Muller, Kerstin; Hsieh, Scott; Maier, Andreas; Gold, Garry; Levenston, Marc; Fahrig, Rebecca

    2016-03-01

    C-arm-based cone-beam CT (CBCT) systems with flat-panel detectors are suitable for diagnostic knee imaging due to their potentially flexible selection of CT trajectories and wide volumetric beam coverage. In knee CT imaging, over-exposure artifacts can occur because of limitations in the dynamic range of the flat panel detectors present on most CBCT systems. We developed a straightforward but effective method for correction and detection of over-exposure for an Automatic Exposure Control (AEC)-enabled standard knee scan incorporating a prior low dose scan. The radiation dose associated with the low dose scan was negligible (0.0042mSv, 2.8% increase) which was enabled by partially sampling the projection images considering the geometry of the knees and lowering the dose further to be able to just see the skin-air interface. We combined the line integrals from the AEC and low dose scans after detecting over-exposed regions by comparing the line profiles of the two scans detector row-wise. The combined line integrals were reconstructed into a volumetric image using filtered back projection. We evaluated our method using in vivo human subject knee data. The proposed method effectively corrected and detected over-exposure, and thus recovered the visibility of exterior tissues (e.g., the shape and density of the patella, and the patellar tendon), incorporating a prior low dose scan with a negligible increase in radiation exposure.

  10. CT diagnosis of unsuspected pneumothorax after blunt abdominal trauma

    Energy Technology Data Exchange (ETDEWEB)

    Wall, S.D. (Univ. of California, San Francisco); Federle, M.P.; Jeffrey, R.B.; Brett, C.M.

    1983-11-01

    Review of abdominal CT scans for evaluation of blunt abdominal trauma yielded 35 cases of pneumothorax, 10 of which had not been diagnosed before CT by clinical examination of plain radiographs. Of the 10 cases initially diagnosed on CT, seven required tube thoracostomy for treatment of the pneumothorax. CT detection of pneumothorax is especially important if mechanical assisted ventilation or general anesthesia is used. Demonstration of pneumothorax requires viewing CT scans of the upper abdomen (lower thorax) at lung windows in addition to the usual soft-tissue windows.

  11. Test-retest reliability of tibiofemoral joint space width measurements made using a low-dose standing CT scanner

    Energy Technology Data Exchange (ETDEWEB)

    Segal, Neil A. [University of Kansas Medical Center, Department of Rehabilitation Medicine, 3901 Rainbow Boulevard, Mailstop 1046, Kansas City, KS (United States); The University of Iowa, Iowa City, IA (United States); Bergin, John; Kern, Andrew; Findlay, Christian [The University of Iowa, Iowa City, IA (United States); Anderson, Donald D. [The University of Iowa, Department of Orthopaedics and Rehabilitation, Iowa City, IA (United States)

    2017-02-15

    To determine the test-retest reliability of knee joint space width (JSW) measurements made using standing CT (SCT) imaging. This prospective two-visit study included 50 knees from 30 subjects (66% female; mean ± SD age 58.2 ± 11.3 years; BMI 29.1 ± 5.6 kg/m{sup 2}; 38% KL grade 0-1). Tibiofemoral geometry was obtained from bilateral, approximately 20 fixed-flexed SCT images acquired at visits 2 weeks apart. For each compartment, the total joint area was defined as the area with a JSW <10 mm. The summary measurements of interest were the percentage of the total joint area with a JSW less than 0.5-mm thresholds between 2.0 and 5.0 mm in each tibiofemoral compartment. Test-retest reliability of the summary JSW measurements was assessed by intraclass correlation coefficients (ICC 2,1) for the percentage area engaged at each threshold of JSW and root-mean-square errors (RMSE) were calculated to assess reproducibility. The ICCs were excellent for each threshold assessed, ranging from 0.95 to 0.97 for the lateral and 0.90 to 0.97 for the medial compartment. RMSE ranged from 1.1 to 7.2% for the lateral and from 3.1 to 9.1% for the medial compartment, with better reproducibility at smaller JSW thresholds. The knee joint positioning protocol used demonstrated high day-to-day reliability for SCT 3D tibiofemoral JSW summary measurements repeated 2 weeks apart. Low-dose SCT provides a great deal of information about the joint while maintaining high reliability, making it a suitable alternative to plain radiographs for evaluating JSW in people with knee OA. (orig.)

  12. Impact of image denoising on image quality, quantitative parameters and sensitivity of ultra-low-dose volume perfusion CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Brockmann, Carolin; Afat, Saif; Pjontek, Rastislav; Nikoubashman, Omid; Brockmann, Marc A.; Wiesmann, Martin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Yang, Zepa; Kim, Changwon [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Nikolaou, Konstantin [Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Kim, Jong Hyo [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Advanced Institute of Convergence Technology, Center for Medical-IT Convergence Technology Research, Suwon (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of)

    2016-01-15

    To examine the impact of denoising on ultra-low-dose volume perfusion CT (ULD-VPCT) imaging in acute stroke. Simulated ULD-VPCT data sets at 20 % dose rate were generated from perfusion data sets of 20 patients with suspected ischemic stroke acquired at 80 kVp/180 mAs. Four data sets were generated from each ULD-VPCT data set: not-denoised (ND); denoised using spatiotemporal filter (D1); denoised using quanta-stream diffusion technique (D2); combination of both methods (D1 + D2). Signal-to-noise ratio (SNR) was measured in the resulting 100 data sets. Image quality, presence/absence of ischemic lesions, CBV and CBF scores according to a modified ASPECTS score were assessed by two blinded readers. SNR and qualitative scores were highest for D1 + D2 and lowest for ND (all p ≤ 0.001). In 25 % of the patients, ND maps were not assessable and therefore excluded from further analyses. Compared to original data sets, in D2 and D1 + D2, readers correctly identified all patients with ischemic lesions (sensitivity 1.0, kappa 1.0). Lesion size was most accurately estimated for D1 + D2 with a sensitivity of 1.0 (CBV) and 0.94 (CBF) and an inter-rater agreement of 1.0 and 0.92, respectively. An appropriate combination of denoising techniques applied in ULD-VPCT produces diagnostically sufficient perfusion maps at substantially reduced dose rates as low as 20 % of the normal scan. (orig.)

  13. Comparison of low-dose sequences of dual-source CT and echocardiography for preoperative evaluation of aortic valve disease

    Institute of Scientific and Technical Information of China (English)

    FENG Juan; WANG Xi-ming; JI Xiao-peng; LI Hai-ou; LI Qiao; GUO Wen-bin; WANG Zheng-jun

    2013-01-01

    Background Accurate evaluation of coronary artery,aortic valve annulus diameter (AVAD),and cardiac function in patients with aortic valve disease is of great significance for surgical strategy.In this study,we explored the preoperative evaluation of low-dose sequence (MinDose sequence) scan of dual-source CT (DSCT) for those patients.Methods Forty patients suspected for aortic valve disease (the experimental group) underwent MinDose sequence of DSCT to observe coronary artery,AVAD,and left ventricular ejection fraction (LVEF).Another 33 subjects suspected for coronary artery disease (the control group) underwent conventional retrospective electrocardiographically-gated sequence of DSCT.Two-dimensional transthoracic echocardiography (2D-TTE) and four-dimensional transthoracic echocardiography (4D-TTE) were applied in the experimental group to measure AVAD and LVEF and compared with MinDose-DSCT.Results There was a strong correlation between LVEFs measured by 2D-TTE and MinDose-DSCT (r=0.87,P <0.01),as well as between 4D-TTE and MinDose-DSCT (r=0.90,P <0.01).AVAD measured by MinDose-DSCT was in good agreement with corresponding measurements by 2D-TTE (r=0.90,P <0.01).The effective dose in the experimental group was 63.54% lower than that in the control group.Conclusions MinDose sequence of DSCT with a low radiation dose serving as a one-stop preoperative evaluation makes effective assessment of the coronary artery,AVAD,and LVEF for patients with aortic valve disease.

  14. Multidetector CT Findings of Bowel Transection in Blunt Abdominal Trauma

    NARCIS (Netherlands)

    Cho, H.S.; Woo, J.Y.; Hong, H.S.; Park, M.H.; Ha, H.I.; Yang, I.; Lee, Y.; Jung, A.Y.; Hwang, J.Y.

    2013-01-01

    OBJECTIVE: Though a number of CT findings of bowel and mesenteric injuries in blunt abdominal trauma are described in literature, no studies on the specific CT signs of a transected bowel have been published. In the present study we describe the incidence and new CT signs of bowel transection in blu

  15. TU-A-12A-09: Absolute Blood Flow Measurement in a Cardiac Phantom Using Low Dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Ziemer, B; Hubbard, L; Lipinski, J; Molloi, S [University of California, Irvine, CA (United States)

    2014-06-15

    Purpose: To investigate a first pass analysis technique to measure absolute flow from low dose CT images in a cardiac phantom. This technique can be combined with a myocardial mass assignment to yield absolute perfusion using only two volume scans and reduce the radiation dose to the patient. Methods: A four-chamber cardiac phantom and perfusion chamber were constructed from poly-acrylic and connected with tubing to approximate anatomical features. The system was connected to a pulsatile pump, input/output reservoirs and power contrast injector. Flow was varied in the range of 1-2.67 mL/s with the pump operating at 60 beats/min. The system was imaged once a second for 14 seconds with a 320-row scanner (Toshiba Medical Systems) using a contrast-enhanced, prospective-gated cardiac perfusion protocol. Flow was calculated by the following steps: subsequent images of the perfusion volume were subtracted to find the contrast entering the volume; this was normalized by an upstream, known volume region to convert Hounsfield (HU) values to concentration; this was divided by the subtracted images time difference. The technique requires a relatively stable input contrast concentration and no contrast can leave the perfusion volume before the flow measurement is completed. Results: The flow calculated from the images showed an excellent correlation with the known rates. The data was fit to a linear function with slope 1.03, intercept 0.02 and an R{sup 2} value of 0.99. The average root mean square (RMS) error was 0.15 mL/s and the average standard deviation was 0.14 mL/s. The flow rate was stable within 7.7% across the full scan and served to validate model assumptions. Conclusion: Accurate, absolute flow rates were measured from CT images using a conservation of mass model. Measurements can be made using two volume scans which can substantially reduce the radiation dose compared with current dynamic perfusion techniques.

  16. WE-FG-207A-03: Low-Dose Cone-Beam Breast CT: Physics and Technology Development.

    Science.gov (United States)

    Boone, J

    2016-06-01

    dedicated breast CT. The development of large-area flat-panel detectors with field-of-view sufficient to image the entire breast in each projection enabled development of flat-panel cone-beam breast CT. More recently, the availability of complimentary metal-oxide semiconductor (CMOS) detectors with lower system noise and finer pixel pitch, combined with the development of x-ray tubes with focal spot dimensions similar to mammography systems, has shown improved spatial resolution and could improve visualization of microcalcifications. These technological developments promise clinical translation of low-dose cone-beam breast CT. Dedicated photon-counting breast CT (pcBCT) systems represent a novel detector design, which provide high spatial resolution (∼ 100µm) and low mean glandular dose (MGD). The CdTe-based direct conversion detector technology was previously evaluated and confirmed by simulations and basic experiments on laboratory setups [Kalender et al., Eur Radiol 22: 1-8, 2012]. Measurements of dose, technical image quality parameters, and surgical specimens on a pcBCT scanner have been completed. Comparative evaluation of surgical specimens showed that pcBCT outperformed mammography and digital breast tomosynthesis with respect to 3D spatial resolution, detectability of calcifications, and soft tissue delineation. Major barriers to widespread clinical use of BCT relate to radiation dose, imaging of microcalcifications, and adequate coverage of breast tissue near the chest wall. Adequate chest wall coverage is also technically challenging but recent progress in x-ray tube, detector and table design now enables full breast coverage in the majority of patients. At this time, BCT has been deemed to be suitable for diagnostic imaging but not yet for screening. The mean glandular dose (MGD) from BCT has been reported to be between 5.7 to 27.8 mGy, and this range is comparable to, and within the range of, the MGD of 2.6 to 31.6 mGy in diagnostic mammography. In

  17. 低剂量CT扫描颅内出血性疾病%Low-dose CT Scanning of Intracranial Hemorrhagic Disease

    Institute of Scientific and Technical Information of China (English)

    魏应敏; 毛存南

    2014-01-01

    Objective To explore the application of low-dose CT scanning in intracranial hemorrhagic disease. To study the feasibility of low-dose scans in the clinical diagnosis. Methods German Siemens 16-slice spiral CT was used. The scanning dose was reduced by reducing the tube current. 60 cases with intracranial bleeding diseases underwent CT scanning. 30 patients underwent conventional CT scanning, and another 30 cases underwent low-dose CT scanning. Low-dose CT images were compared to the first checked images to evaluate the development of hemorrhagic disease, and compared with conventional CT scanning images. Results Compared with the first scanning images, low-dose CT scanning images showed no significant difference, and the quality of images did not affect the display of lesions and diagnosis. There was no significant difference compared to conventional CT images. Conclusion The patient's radiation dose was significantly reduced by low-dose CT scanning. As a result of low-dose scanning, the consumption of CT machine was also reduced, which could greatly increase the life of machine.%目的:探讨低剂量CT扫描在颅内出血性疾病复查时扫描的应用价值。并研究低剂量扫描在临床诊断中的可行性。方法采用德国西门子公司生产的16排螺旋CT,通过降低管电流来降低扫描剂量,对60例颅内出血性疾病患者复查扫描。其中30例采用常规扫描,另外30例采用低剂量扫描。将低剂量扫描的图像与首次检查图像比较,评价出血性疾病的发展情况。再与常规扫描比较影像学差异。结果低剂量CT扫描所获得的图像清晰,与首次扫描的图像相比,对比度、病灶边缘显示无明显差异,不影响病灶的显示和诊断结果。与常规扫描图像无明显影像学差异。结论低剂量CT扫描对病人的辐射剂量大大降低了。由于采用低剂量扫描,CT机器的消耗也降低了,大大增加了机器的使用寿命。

  18. Value of abdominal CT in the emergency department for patients with abdominal pain

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Max P.; Siewert, Bettina; Bromberg, Rebecca; Raptopoulos, Vassilios [Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215 (United States); Sands, Daniel Z. [Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215 (United States); Edlow, Jonathan [Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215 (United States)

    2003-02-01

    The purpose of our study is to demonstrate the value of CT in the emergency department (ED) for patients with non-traumatic abdominal pain. Between August 1998 and April 1999, 536 consecutive patients with non-traumatic abdominal pain were entered into our study. Using a computer order entry system, physicians were asked to identify: (a) their most likely diagnosis; (b) their level of certainty in their diagnosis; (c) if they thought CT would be normal or abnormal; (d) their treatment plan (prior to knowledge of the CT results); and (e) their role in deciding to order CT. This information was correlated with each patient's post-CT diagnosis and subsequent management. Pre- and post-CT diagnoses were concordant in 200 of 536 (37%) patients. The physicians' certainty in the accuracy of their pre-CT diagnosis was less than high in 88% of patients. Prior to CT, the management plan included hospital admission for 402 patients. Following CT, only 312 patients were actually admitted; thus, the net impact of performing CT was to obviate the need for hospital admission in 90 of 536 (17%) of patients with abdominal pain. Prior to CT, 67 of 536 (13%) of all patients would have undergone immediate surgery; however, following CT only 25 (5%) actually required immediate surgery. Among patients with the four most common pre-CT diagnoses (appendicitis, abscess, diverticulitis, and urinary tract stones) CT had the greatest impact on hospital admission and surgical management for patients with suspected appendicitis. For patients with suspected appendicitis, CT reduced the hospital admission rate in 28% (26 of 91) of patients and changed the surgical management in 40% (39 of 91) of patients. Our study demonstrates the advantage of performing abdominal CT in the ED for patients with non-traumatic abdominal pain. (orig.)

  19. Density of the midpalatal suture after RME treatment – a retrospective comparative low-dose CT-study

    Science.gov (United States)

    2014-01-01

    Introduction Rapid maxillary expansion (RME) is a common technique to improve the dental and skeletal transverse width in cases of constricted maxillary arches. Although retention after RME has been widely examined, there is still no clear statement about the minimal retention time in postpubertal patients and many practitioners have retention concepts varying between three and six months. Methods This retrospective study consisted of 14 patients who were either treated with a Haas-type RME (6 patients) or a Hybrid-RME (8 patients). The average age was 15.8 years (min. 13.5 years, max. 23.0 years). Low-dose CT scans were taken initially before placement of the RME (T0), directly after maximal activation (T1) and (in six cases) also in retention after 6 months (T2). Using a 3D-software (“OnDemand3D”/Cybermed Inc.) in analogy to the method published by Franchi et al. (AJODO Volume 137/ Number 4) all values were measured twice at an interval of 1 month to assess the method error and the intraoperator reliability. Statistical analysis was performed using SPSS 21 for Mac. Possible influences of the RME-type were assessed using the univariate ANOVA. Changes in the sutural density between the different points of time were examined using paired t-tests. Results The density of the suture decreased significantly after expansion (T0-T1) with both types of RME (p = 0.000). In the retention period there was a significant increase of the sutural density (p = 0.007) although it did not achieve the initial level (p = 0.002). Conclusions 1. The midpalatal suture was opened in all analysed patients. 2. In postpubertal patients a retention time of six months does not allow sufficient reorganization of the suture. 3. Therefore, a retention period longer than six months seems to be beneficial to prevent relapses in postpubertal patients. PMID:24884771

  20. Effects of Iterative Reconstruction Algorithms on Computer-assisted Detection (CAD) Software for Lung Nodules in Ultra-low-dose CT for Lung Cancer Screening.

    Science.gov (United States)

    Nomura, Yukihiro; Higaki, Toru; Fujita, Masayo; Miki, Soichiro; Awaya, Yoshikazu; Nakanishi, Toshio; Yoshikawa, Takeharu; Hayashi, Naoto; Awai, Kazuo

    2017-02-01

    This study aimed to evaluate the effects of iterative reconstruction (IR) algorithms on computer-assisted detection (CAD) software for lung nodules in ultra-low-dose computed tomography (ULD-CT) for lung cancer screening. We selected 85 subjects who underwent both a low-dose CT (LD-CT) scan and an additional ULD-CT scan in our lung cancer screening program for high-risk populations. The LD-CT scans were reconstructed with filtered back projection (FBP; LD-FBP). The ULD-CT scans were reconstructed with FBP (ULD-FBP), adaptive iterative dose reduction 3D (AIDR 3D; ULD-AIDR 3D), and forward projected model-based IR solution (FIRST; ULD-FIRST). CAD software for lung nodules was applied to each image dataset, and the performance of the CAD software was compared among the different IR algorithms. The mean volume CT dose indexes were 3.02 mGy (LD-CT) and 0.30 mGy (ULD-CT). For overall nodules, the sensitivities of CAD software at 3.0 false positives per case were 78.7% (LD-FBP), 9.3% (ULD-FBP), 69.4% (ULD-AIDR 3D), and 77.8% (ULD-FIRST). Statistical analysis showed that the sensitivities of ULD-AIDR 3D and ULD-FIRST were significantly higher than that of ULD-FBP (P CAD software in ULD-CT was improved by using IR algorithms. In particular, the performance of CAD in ULD-FIRST was almost equivalent to that in LD-FBP. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  1. Using Abdominal CT Data for Visceral Fat Evaluation

    OpenAIRE

    2013-01-01

    Background: Quantitative assessment of body fat is important for the diagnosis and treatment of diseases related to obesity, Computed tomography (CT) becoming the standard procedure for measuring the abdominal fat distribution. Material and method: The retrospective study included 111 inpatients, who underwent routine abdominal CT exams in the Radiology Laboratory of SCJU Tg.Mures (2013). MPR MDCT (SOMATOM AS 64) data was processed using a custom written MATLAB R2009b software, ImageJ being u...

  2. Prospective ECG triggering versus low-dose retrospective ECG-gated 128-channel CT coronary angiography: comparison of image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Q.; Yin, Y.; Hua, X.; Zhu, R.; Hua, J. [Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Xu, J., E-mail: xujianr@hotmail.co [Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China)

    2010-10-15

    Aim: To evaluate image quality and radiation dose for 128-detector prospective electrocardiogram (ECG)-gated computed tomography coronary angiography (CTCA) compared with a low-dose retrospective ECG-gated imaging protocol. Materials and methods: Thirty-one and 47 patients suspected of having coronary artery disease were enrolled into groups examined using prospective and low-dose retrospective ECG-gated CT protocols respectively. All examinations were performed on a 128-detector CT system (Definition AS, Siemens Healthcare, Forchheim, Germany). Prospective CTCA was performed using following parameters: tube voltage 100 kV; tube current 205 mAs; centre of acquisition window 70% of the RR interval. The tube current for low-dose retrospective ECG-gated CTCA was full dose during 40-70% of the RR interval and partial dose for the rest of RR interval. The pitch varied between 0.2 and 0.5 depending on heart rate and patient size. Image quality of coronary arteries was evaluated using a four-point grading scale. The signal-to-noise ratios (SNRs) of enhanced arteries and myocardium were also measured, corresponding contrast-to-noise ratios (CNRs) were calculated, and the radiation doses received were recorded. Results: There was a significant difference in the image quality scores between the retrospective and prospective gating protocols (Chi-square = 15.331, p = 0.009). There was no significant difference between the SNRs of the contrasted artery and myocardium in these two groups, but the CNRs were increased in the prospective group. The mean radiation dose of prospective gating group was 2.71 {+-} 0.67 mSv (range, 1.67-3.59 mSv), which was significantly lower than that of the retrospective group (p < 0.001). Conclusion: Prospective CT angiography can achieve lower radiation dose than that of low-dose retrospective CT angiography, with preserved image quality.

  3. Low-Dose and Scatter-Free Cone-Beam CT Imaging Using a Stationary Beam Blocker in a Single Scan: Phantom Studies

    Directory of Open Access Journals (Sweden)

    Xue Dong

    2013-01-01

    Full Text Available Excessive imaging dose from repeated scans and poor image quality mainly due to scatter contamination are the two bottlenecks of cone-beam CT (CBCT imaging. Compressed sensing (CS reconstruction algorithms show promises in recovering faithful signals from low-dose projection data but do not serve well the needs of accurate CBCT imaging if effective scatter correction is not in place. Scatter can be accurately measured and removed using measurement-based methods. However, these approaches are considered unpractical in the conventional FDK reconstruction, due to the inevitable primary loss for scatter measurement. We combine measurement-based scatter correction and CS-based iterative reconstruction to generate scatter-free images from low-dose projections. We distribute blocked areas on the detector where primary signals are considered redundant in a full scan. Scatter distribution is estimated by interpolating/extrapolating measured scatter samples inside blocked areas. CS-based iterative reconstruction is finally carried out on the undersampled data to obtain scatter-free and low-dose CBCT images. With only 25% of conventional full-scan dose, our method reduces the average CT number error from 250 HU to 24 HU and increases the contrast by a factor of 2.1 on Catphan 600 phantom. On an anthropomorphic head phantom, the average CT number error is reduced from 224 HU to 10 HU in the central uniform area.

  4. Radiation exposure and image quality in staged low-dose protocols for coronary dual-source CT angiography: a randomized comparison

    Energy Technology Data Exchange (ETDEWEB)

    Pflederer, Tobias; Jakstat, Josy; Marwan, Mohamed; Schepis, Tiziano; Bachmann, Sven; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G.; Achenbach, Stephan [University of Erlangen, Department of Internal Medicine 2, Erlangen (Germany); Kuettner, Axel; Anders, Katharina; Lell, Michael [University of Erlangen, Institute of Diagnostic Radiology, Erlangen (Germany)

    2010-05-15

    To evaluate staged low-dose approaches for coronary CT angiography (CTA) in which a standard sequence was added if the low-dose sequence did not allow reliable rule-out of coronary stenosis. A total of 176 consecutive patients referred for dual-source CTA were randomized to three protocols: group 1 using prospective ECG-triggering (100 kV, 330 mAs), group 2 a retrospectively gated ''MinDose'' sequence (100 kV, 330 mAs) and group 3 a standard spiral sequence (120 kV, 400 mAs). If image quality in low-dose groups 1 or 2 was non-diagnostic, an additional standard CT examination (as in group 3) was performed. Non-diagnostic image quality was found in 11/56, 4/55, and 2/65 patients (46/896, 4/880 and 3/1,040 coronary segments) in groups 1, 2 and 3, respectively. Median (interquartile ranges) volumes of contrast material, CTDI{sub vol}, DLP and effective dose for low-dose groups 1 and 2 and for standard group 3 were 92.5 (11.3), 75.0 (2.5) and 75.0 (9.0) ml; 8.0 (1.4), 16.8 (4.8) and 48.1 (14.2) mGy; 108.0 (27.3), 246.0 (93.0) and 701.0 (207.8) mGy cm; and 1.5 (0.4), 3.4 (1.3) and 9.8 (2.9) mSv, respectively. A staged coronary CTA protocol with an initial low-dose approach and addition of a standard sequence - should image quality be too low - can lead to a substantial reduction in radiation exposure. (orig.)

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

    CERN Document Server

    Yan, Hao; Jia, Xun; Jiang, Steve B

    2011-01-01

    While compressed sensing (CS) based reconstructions have been developed for low-dose CBCT, a clear understanding on the relationship between the image quality and imaging dose at low dose levels is needed. In this paper, we qualitatively investigate this subject in a comprehensive manner with extensive experimental and simulation studies. The basic idea is to plot image quality and imaging dose together as functions of number of projections and mAs per projection over the whole clinically relevant range. A clear understanding on the tradeoff between image quality and dose can be achieved and optimal low-dose CBCT scan protocols can be developed for various imaging tasks in IGRT. Main findings of this work include: 1) Under the CS framework, image quality has little degradation over a large dose range, and the degradation becomes evident when the dose < 100 total mAs. A dose < 40 total mAs leads to a dramatic image degradation. Optimal low-dose CBCT scan protocols likely fall in the dose range of 40-100 ...

  6. Small pulmonary nodules in baseline and incidence screening rounds of low-dose CT lung cancer screening

    NARCIS (Netherlands)

    Walter, Joan E; Heuvelmans, Marjolein A; Oudkerk, Matthijs

    Currently, lung cancer screening by low-dose computed tomography (LDCT) is widely recommended for high-risk individuals by US guidelines, but there still is an ongoing debate concerning respective recommendations for European countries. Nevertheless, the available data regarding pulmonary nodules

  7. Low-dose 4D cone-beam CT via joint spatiotemporal regularization of tensor framelet and nonlocal total variation

    Science.gov (United States)

    Han, Hao; Gao, Hao; Xing, Lei

    2017-08-01

    Excessive radiation exposure is still a major concern in 4D cone-beam computed tomography (4D-CBCT) due to its prolonged scanning duration. Radiation dose can be effectively reduced by either under-sampling the x-ray projections or reducing the x-ray flux. However, 4D-CBCT reconstruction under such low-dose protocols is prone to image artifacts and noise. In this work, we propose a novel joint regularization-based iterative reconstruction method for low-dose 4D-CBCT. To tackle the under-sampling problem, we employ spatiotemporal tensor framelet (STF) regularization to take advantage of the spatiotemporal coherence of the patient anatomy in 4D images. To simultaneously suppress the image noise caused by photon starvation, we also incorporate spatiotemporal nonlocal total variation (SNTV) regularization to make use of the nonlocal self-recursiveness of anatomical structures in the spatial and temporal domains. Under the joint STF-SNTV regularization, the proposed iterative reconstruction approach is evaluated first using two digital phantoms and then using physical experiment data in the low-dose context of both under-sampled and noisy projections. Compared with existing approaches via either STF or SNTV regularization alone, the presented hybrid approach achieves improved image quality, and is particularly effective for the reconstruction of low-dose 4D-CBCT data that are not only sparse but noisy.

  8. Prospective randomised comparison of diagnostic confidence and image quality with normal-dose and low-dose CT pulmonary angiography at various body weights

    Energy Technology Data Exchange (ETDEWEB)

    Szucs-Farkas, Zsolt [University Hospital Bern, University Institute of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Berne (Switzerland); Hospital Centre of Biel, Institute of Radiology, Biel/Bienne (Switzerland); Megyeri, Boglarka [University of Debrecen, Health and Medical Science Centre, Department of Anaesthesiology and Intensive Care, Debrecen (Hungary); Christe, Andreas; Vock, Peter; Heverhagen, Johannes T. [University Hospital Bern, University Institute of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Berne (Switzerland); Schindera, Sebastian T. [University Hospital Bern, University Institute of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Berne (Switzerland); University Hospital Basel, Department of Radiology, Basel (Switzerland)

    2014-08-15

    To find a threshold body weight (BW) below 100 kg above which computed tomography pulmonary angiography (CTPA) using reduced radiation and a reduced contrast material (CM) dose provides significantly impaired quality and diagnostic confidence compared with standard-dose CTPA. In this prospectively randomised study of 501 patients with suspected pulmonary embolism and BW <100 kg, 246 were allocated into the low-dose group (80 kVp, 75 ml CM) and 255 into the normal-dose group (100 kVp, 100 ml CM). Contrast-to-noise ratio (CNR) in the pulmonary trunk was calculated. Two blinded chest radiologists independently evaluated subjective image quality and diagnostic confidence. Data were compared between the normal-dose and low-dose groups in five BW subgroups. Vessel attenuation did not differ between the normal-dose and low-dose groups within each BW subgroup (P = 1.0). The CNR was higher with the normal-dose compared with the low-dose protocol (P < 0.006) in all BW subgroups except for the 90-99 kg subgroup (P = 0.812). Subjective image quality and diagnostic confidence did not differ between CT protocols in all subgroups (P between 0.960 and 1.0). Subjective image quality and diagnostic confidence with 80 kVp CTPA is not different from normal-dose protocol in any BW group up to 100 kg. (orig.)

  9. Abdominal actinomycosis associated with intrauterine device: CT features.

    Science.gov (United States)

    Laurent, T; de Grandi, P; Schnyder, P

    1996-01-01

    Abdominal actinomycosis is a severe and progressive peritoneal infection, due to an anerobic gram-positive bacterium, Actinomyces israelii. The presence of a long-standing intrauterine device (IUD) is a well-known risk factor in young women. We report two cases of pelviperitoneal actinomycosis appearing in two young women with acute low abdominal pain. Abdominal CT demonstrated multiple solid or encapsulated peritoneal masses with marked contrast enhancement and infiltration of the adjacent mesenteric fat. Laparoscopy confirmed the presence of intraperitoneal abscesses which contained Actinomyces israelii. High doses of amoxicillin and clavulanic acid (Augmentine) were given and following CT scan after 2 and 6 weeks showed a slow, but complete, resolution of the lesions. Although the radiologic presentation of actinomycosis is nonspecific, the diagnosis should be raised in the presence of pseudotumoral mesenteric infiltration, particularly in young women with an IUD. Abdominal CT is a useful method for diagnosis and for follow-up.

  10. CT findings of benign omental lesions following abdominal cancer surgery

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Yun; Kim, Dong Won; Cho, Jin Han; Kwon, Hee Jin; Ha, Dong Ho; Oh, Jong Young [Diagnostic Radiology, Dong-A University College of Medicine, Busan (Korea, Republic of)

    2016-07-15

    The greater omentum is the largest peritoneal fold and can be the origin of primary pathologic conditions, as well as a boundary and conduit for disease processes. Most diseases involving the omentum manifest with nonspecific and overlapping features on computed tomography (CT). In particular, varying benign disease processes of traumatic, inflammatory, vascular, or systemic origin can occur in the omentum during the follow-up period after surgery for intra-abdominal malignancy. It can be challenging for radiologists due to various spectrum of CT findings. Thus, we reviewed the CT findings of various benign omental lesions after surgery for intra-abdominal malignancy.

  11. A low-dose and an ultra-low-dose contrast agent protocol for coronary CT angiography in a clinical setting: quantitative and qualitative comparison to a standard dose protocol.

    Science.gov (United States)

    Benz, Dominik C; Gräni, Christoph; Hirt Moch, Beatrice; Mikulicic, Fran; Vontobel, Jan; Fuchs, Tobias A; Stehli, Julia; Clerc, Olivier F; Possner, Mathias; Pazhenkottil, Aju P; Gaemperli, Oliver; Buechel, Ronny R; Kaufmann, Philipp A

    2017-06-01

    To evaluate the impact of a low-dose (LD) and an ultra-LD (ULD) contrast protocol for coronary CT angiography on qualitative and quantitative image parameters in a clinical setting. We scanned 120 consecutive patients with a 256-slice CT scanner applying a LD (60 patients, 35-55 ml) or ULD (60 patients, 25-45 ml) contrast protocol adapted to the body mass index. Visually assessed image quality and attenuation measured in each coronary segment were retrospectively compared in 20 consecutive patients scanned with a normal-dose (ND, 40-105 ml) contrast protocol. Visually assessed image quality did not differ significantly among protocols. By contrast, attenuation obtained from the ULD protocol (median contrast volume 35 ml) differed significantly from the LD (median 45 ml) and ND (median 70 ml) protocols in the coronary segments (316 ± 52 vs 363 ± 60 and 359 ± 52 HU, p < 0.001). Attenuation did not differ significantly between the LD and ND protocol. The proportion of patients with inadequate coronary vessel attenuation was significantly higher (p < 0.001) in the ULD protocol (37%) than in the ND (5%) and LD (10%) protocols but did not differ significantly between the ND and LD protocols. In a clinical setting, a LD contrast protocol with a median volume of 45 ml is feasible for the latest generation 256-slice coronary CT angiography as it yields attenuation comparable to a ND protocol. By contrast, the implementation of an ULD protocol remains challenging. Advances in knowledge: Although not perceived by the naked eye, an ULD contrast protocol in a clinical setting yields attenuation below a threshold for diagnostic image quality.

  12. Low-dose CT imaging of a total hip arthroplasty phantom using model-based iterative reconstruction and orthopedic metal artifact reduction

    Energy Technology Data Exchange (ETDEWEB)

    Wellenberg, R.H.H.; Streekstra, G.J.; Maas, M. [Academic Medical Center, Department of Radiology, Amsterdam (Netherlands); Boomsma, M.F.; Osch, J.A.C. van [Department of Radiology, Zwolle (Netherlands); Vlassenbroek, A. [Philips Medical Systems, Brussels (Belgium); Milles, J. [Philips Medical Systems, Eindhoven (Netherlands); Edens, M.A. [Department of Innovation and Science, Zwolle (Netherlands); Slump, C.H. [University of Twente, MIRA Institute for Biomedical Technology and Technical Medicine, Enschede (Netherlands)

    2017-05-15

    To compare quantitative measures of image quality, in terms of CT number accuracy, noise, signal-to-noise-ratios (SNRs), and contrast-to-noise ratios (CNRs), at different dose levels with filtered-back-projection (FBP), iterative reconstruction (IR), and model-based iterative reconstruction (MBIR) alone and in combination with orthopedic metal artifact reduction (O-MAR) in a total hip arthroplasty (THA) phantom. Scans were acquired from high- to low-dose (CTDI{sub vol}: 40.0, 32.0, 24.0, 16.0, 8.0, and 4.0 mGy) at 120- and 140- kVp. Images were reconstructed using FBP, IR (iDose{sup 4} level 2, 4, and 6) and MBIR (IMR, level 1, 2, and 3) with and without O-MAR. CT number accuracy in Hounsfield Units (HU), noise or standard deviation, SNRs, and CNRs were analyzed. The IMR technique showed lower noise levels (p < 0.01), higher SNRs (p < 0.001) and CNRs (p < 0.001) compared with FBP and iDose{sup 4} in all acquisitions from high- to low-dose with constant CT numbers. O-MAR reduced noise (p < 0.01) and improved SNRs (p < 0.01) and CNRs (p < 0.001) while improving CT number accuracy only at a low dose. At the low dose of 4.0 mGy, IMR level 1, 2, and 3 showed 83%, 89%, and 95% lower noise values, a factor 6.0, 9.2, and 17.9 higher SNRs, and 5.7, 8.8, and 18.2 higher CNRs compared with FBP respectively. Based on quantitative analysis of CT number accuracy, noise values, SNRs, and CNRs, we conclude that the combined use of IMR and O-MAR enables a reduction in radiation dose of 83% compared with FBP and iDose{sup 4} in the CT imaging of a THA phantom. (orig.)

  13. Chest computed tomography using iterative reconstruction vs filtered back projection (Part 2): image quality of low-dose CT examinations in 80 patients

    Energy Technology Data Exchange (ETDEWEB)

    Pontana, Francois; Pagniez, Julien; Faivre, Jean-Baptiste; Hachulla, Anne-Lise; Remy, Jacques [University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain [University Lille Nord de France, Department of Medical Statistics, Lille (France); Flohr, Thomas [Computed Tomography Division, Siemens Healthcare, Forchheim (Germany); Remy-Jardin, Martine [University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Hospital Calmette, Department of Thoracic Imaging, Lille cedex (France)

    2011-03-15

    To evaluate the image quality of an iterative reconstruction algorithm (IRIS) in low-dose chest CT in comparison with standard-dose filtered back projection (FBP) CT. Eighty consecutive patients referred for a follow-up chest CT examination of the chest, underwent a low-dose CT examination (Group 2) in similar technical conditions to those of the initial examination, (Group 1) except for the milliamperage selection and the replacement of regular FBP reconstruction by iterative reconstructions using three (Group 2a) and five iterations (Group 2b). Despite a mean decrease of 35.5% in the dose-length-product, there was no statistically significant difference between Group 2a and Group 1 in the objective noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios and distribution of the overall image quality scores. Compared to Group 1, objective image noise in Group 2b was significantly reduced with increased SNR and CNR and a trend towards improved image quality. Iterative reconstructions using three iterations provide similar image quality compared with the conventionally used FBP reconstruction at 35% less dose, thus enabling dose reduction without loss of diagnostic information. According to our preliminary results, even higher dose reductions than 35% may be feasible by using more than three iterations. (orig.)

  14. Ultra-low dose abdominal MDCT: Using a knowledge-based Iterative Model Reconstruction technique for substantial dose reduction in a prospective clinical study

    Energy Technology Data Exchange (ETDEWEB)

    Khawaja, Ranish Deedar Ali, E-mail: rkhawaja@mgh.harvard.edu [MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Singh, Sarabjeet; Blake, Michael; Harisinghani, Mukesh; Choy, Gary; Karosmangulu, Ali; Padole, Atul; Do, Synho [MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Brown, Kevin; Thompson, Richard; Morton, Thomas; Raihani, Nilgoun [CT Research and Advanced Development, Philips Healthcare, Cleveland, OH (United States); Koehler, Thomas [Philips Technologie GmbH, Innovative Technologies, Hamburg (Germany); Kalra, Mannudeep K. [MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2015-01-15

    Highlights: • Limited abdominal CT indications can be performed at a size specific dose estimate of (SSDE) 1.5 mGy (∼0.9 mSv) in smaller patients (BMI less than or equal to 25 kg/m{sup 2}) using a knowledge based Iterative Model Reconstruction (IMR) technique. • Evaluation of liver tumors and pathologies is unacceptable at this reduced dose with IMR technique especially in patients with a BMI greater than 25 kg/m{sup 2}. • IMR body soft tissue and routine settings perform substantially better than IMR sharp plus setting in reduced dose CT images. • At SSDE of 1.5 mGy, objective image noise in reduced dose IMR images is 8–56% less than compared to standard dose FBP images, with lowest image noise in IMR body-soft tissue images. - Abstract: Purpose: To assess lesion detection and image quality parameters of a knowledge-based Iterative Model Reconstruction (IMR) in reduced dose (RD) abdominal CT examinations. Materials and methods: This IRB-approved prospective study included 82 abdominal CT examinations performed for 41 consecutive patients (mean age, 62 ± 12 years; F:M 28:13) who underwent a RD CT (SSDE, 1.5 mGy ± 0.4 [∼0.9 mSv] at 120 kV with 17–20 mAs/slice) immediately after their standard dose (SD) CT exam (10 mGy ± 3 [∼6 mSv] at 120 kV with automatic exposure control) on 256 MDCT (iCT, Philips Healthcare). SD data were reconstructed using filtered back projection (FBP). RD data were reconstructed with FBP and IMR. Four radiologists used a five-point scale (1 = image quality better than SD CT to 5 = image quality unacceptable) to assess both subjective image quality and artifacts. Lesions were first detected on RD FBP images. RD IMR and RD FBP images were then compared side-by-side to SD-FBP images in an independent, randomized and blinded fashion. Friedman's test and intraclass correlation coefficient were used for data analysis. Objective measurements included image noise and attenuation as well as noise spectral density (NSD) curves

  15. Adaptive iterative dose reduction (AIDR) 3D in low dose CT abdomen-pelvis: Effects on image quality and radiation exposure

    Science.gov (United States)

    Ang, W. C.; Hashim, S.; Karim, M. K. A.; Bahruddin, N. A.; Salehhon, N.; Musa, Y.

    2017-05-01

    The widespread use of computed tomography (CT) has increased the medical radiation exposure and cancer risk. We aimed to evaluate the impact of AIDR 3D in CT abdomen-pelvic examinations based on image quality and radiation dose in low dose (LD) setting compared to standard dose (STD) with filtered back projection (FBP) reconstruction. We retrospectively reviewed the images of 40 patients who underwent CT abdomen-pelvic using a 80 slice CT scanner. Group 1 patients (n=20, mean age 41 ± 17 years) were performed at LD with AIDR 3D reconstruction and Group 2 patients (n=20, mean age 52 ± 21 years) were scanned with STD using FBP reconstruction. Objective image noise was assessed by region of interest (ROI) measurements in the liver and aorta as standard deviation (SD) of the attenuation value (Hounsfield Unit, HU) while subjective image quality was evaluated by two radiologists. Statistical analysis was used to compare the scan length, CT dose index volume (CTDIvol) and image quality of both patient groups. Although both groups have similar mean scan length, the CTDIvol significantly decreased by 38% in LD CT compared to STD CT (pabdomen-pelvis.

  16. CT detection and aspiration of abdominal abscesses.

    Science.gov (United States)

    Haaga, J R; Alfidi, R J; Havrilla, T R; Cooperman, A M; Seidelmann, F E; Reich, N E; Weinstein, A J; Meaney, T F

    1977-03-01

    Computed tomography (CT) is effective in detecting intraabdominal abscesses. Loculations of fluid and extraluminal gas are clearly localized in relation to other organs. Of 22 abscess in this series, CT successfully detected 20; comparative information with gallium, techneticum, and ultrasound scans is presented. In addition to localizing these collections, CT can be used to guide needle aspiration and drainage procedures. Three sizes of needles were used to aspirate specimens and/or provide drainage. This was accomplished successfully in 12 of 14 CT-guided procedures.

  17. Investigation of sinonasal anatomy via low-dose multidetector CT examination in chronic rhinosinusitis patients with higher risk for perioperative complications.

    Science.gov (United States)

    Fraczek, Marcin; Guzinski, Maciej; Morawska-Kochman, Monika; Krecicki, Tomasz

    2017-02-01

    The aim of the study was to compare visualisation of the surgically relevant anatomical structures via low- and standard-dose multidetector CT protocol in patients with chronic rhinosinusitis (CRS) and higher risk for perioperative complications (i.e. presence of bronchial asthma, history of sinus surgery and advanced nasal polyposis). 135 adult CRS patients were divided randomly into standard-dose (120 kVp, 100 mAs) or low-dose CT groups (120 kVp, 45 mAs). The detectability of the vital anatomical structures (anterior ethmoid artery, optic nerve, cribriform plate and lamina papyracea) was scored using a five-point scale (from excellent to unacceptable) by a radiologist and sinus surgeon. Polyp sizes were quantified endoscopically according to the Lildholdt's scale (LS). Olfactory function was tested with the "Sniffin' Sticks" test. On the low-dose CT images, detectability ranged from 2.42 (better than poor) for cribriform plate among anosmic cases to 4.11 (better than good) for lamina papyracea in cases without nasal polyps. Identification of lamina papyracea on low-dose scans was significantly worse in each group and the same was the case with cribriform plates in patients with advanced polyposis and anosmia. Cribriform plates were the most poorly identified (between poor and average) among all the structures on low-dose images. Identification of anterior ethmoid artery (AEA) with reduced dose was insignificantly worse than with standard-dose examination. The AEA was scored as an average-defined structure and was the second weakest visualised. In conclusion, preoperatively, low-dose protocols may not sufficiently visualise the surgically relevant anatomical structures in patients with CRS and bronchial asthma, advanced nasal polyps (LS > 2) and history of sinus surgery. Low mAs value enables comparable detectability of sinonasal landmarks with standard-dose protocols in patients without analysed risk factors. In the context of planned surgery, the current

  18. 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.)

  19. Abdominal actinomycosis associated with intrauterine device: CT features

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, T. [Dept. of Radiology, CHUV-1011, Lausanne (Switzerland); Grandi, P. de [Dept. of Gynecology-Obstetrics, CHUV-1011, Lausame (Switzerland); Schnyder, P. [Dept. of Radiology, CHUV-1011, Lausanne (Switzerland)

    1996-10-01

    We report two cases of pelviperitoneal actinomycosis appearing in two young women with acute low abdominal pain. Abdominal CT demonstrated multiple solid or encapsulated peritoneal masses with marked contrast enhancement and infiltration of the adjacent mesenteric fat. Laparoscopy confirmed the presence of intraperitoneal abscesses which contained Actinomyces israelii. High doses of amoxicillin and clavulanic acid (Augmentine) were given and following CT scan after 2 and 6 weeks showed a slow, but complete, resolution of the lesions. Although the radiologic presentation of actinomycosis is nonspecific, the diagnosis should be raised in the presence of pseudotumoral mesenteric infiltration, particularly in young women with an IUD. Abdominal CT is a useful method for diagnosis and for follow-up. (orig./MG)

  20. Lung cancer probability in patients with CT-detected pulmonary nodules: a prespecified analysis of data from the NELSON trial of low-dose CT screening.

    Science.gov (United States)

    Horeweg, Nanda; van Rosmalen, Joost; Heuvelmans, Marjolein A; van der Aalst, Carlijn M; Vliegenthart, Rozemarijn; Scholten, Ernst Th; ten Haaf, Kevin; Nackaerts, Kristiaan; Lammers, Jan-Willem J; Weenink, Carla; Groen, Harry J; van Ooijen, Peter; de Jong, Pim A; de Bock, Geertruida H; Mali, Willem; de Koning, Harry J; Oudkerk, Matthijs

    2014-11-01

    The main challenge in CT screening for lung cancer is the high prevalence of pulmonary nodules and the relatively low incidence of lung cancer. Management protocols use thresholds for nodule size and growth rate to determine which nodules require additional diagnostic procedures, but these should be based on individuals' probabilities of developing lung cancer. In this prespecified analysis, using data from the NELSON CT screening trial, we aimed to quantify how nodule diameter, volume, and volume doubling time affect the probability of developing lung cancer within 2 years of a CT scan, and to propose and evaluate thresholds for management protocols. Eligible participants in the NELSON trial were those aged 50-75 years, who have smoked 15 cigarettes or more per day for more than 25 years, or ten cigarettes or more for more than 30 years and were still smoking, or had stopped smoking less than 10 years ago. Participants were randomly assigned to low-dose CT screening at increasing intervals, or no screening. We included all participants assigned to the screening group who had attended at least one round of screening, and whose results were available from the national cancer registry database. We calculated lung cancer probabilities, stratified by nodule diameter, volume, and volume doubling time and did logistic regression analysis using diameter, volume, volume doubling time, and multinodularity as potential predictor variables. We assessed management strategies based on nodule threshold characteristics for specificity and sensitivity, and compared them to the American College of Chest Physicians (ACCP) guidelines. The NELSON trial is registered at www.trialregister.nl, number ISRCTN63545820. Volume, volume doubling time, and volumetry-based diameter of 9681 non-calcified nodules detected by CT screening in 7155 participants in the screening group of NELSON were used to quantify lung cancer probability. Lung cancer probability was low in participants with a nodule

  1. 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.

  2. Inter-observer agreement for abdominal CT in unselected patients with acute abdominal pain

    Energy Technology Data Exchange (ETDEWEB)

    Randen, Adrienne van [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); University of Amsterdam, Department of Surgery, Academic Medical Center, Amsterdam (Netherlands); Academic Medical Center, Amsterdam (Netherlands); Lameris, Wytze [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); University of Amsterdam, Department of Surgery, Academic Medical Center, Amsterdam (Netherlands); Nio, C.Y.; Spijkerboer, Anje M.; Meier, Mark A.; Tutein Nolthenius, Charlotte; Smithuis, Frank; Stoker, Jaap [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); Bossuyt, Patrick M. [University of Amsterdam, Department of Clinical Epidemiology, Biostatistics, and Bioinformatics, Academic Medical Center, Amsterdam (Netherlands); Boermeester, Marja A. [University of Amsterdam, Department of Surgery, Academic Medical Center, Amsterdam (Netherlands)

    2009-06-15

    The level of inter-observer agreement of abdominal computed tomography (CT) in unselected patients presenting with acute abdominal pain at the Emergency Department (ED) was evaluated. Two hundred consecutive patients with acute abdominal pain were prospectively included. Multi-slice CT was performed in all patients with intravenous contrast medium only. Three radiologists independently read all CT examinations. They recorded specific radiological features and a final diagnosis on a case record form. We calculated the proportion of agreement and kappa values, for overall, urgent and frequently occurring diagnoses. The mean age of the evaluated patients was 46 years (range 19-94), of which 54% were women. Overall agreement on diagnoses was good, with a median kappa of 0.66. Kappa values for specific urgent diagnoses were excellent, with median kappa values of 0.84, 0.90 and 0.81, for appendicitis, diverticulitis and bowel obstruction, respectively. Abdominal CT has good inter-observer agreement in unselected patients with acute abdominal pain at the ED, with excellent agreement for specific urgent diagnoses as diverticulitis and appendicitis. (orig.)

  3. Abdominal wall lipoma--CT and MRI appearance.

    Science.gov (United States)

    Bloom, R A; Gomori, J M; Fields, S I; Katz, E

    1991-01-01

    Although soft tissue lipomata are common tumours, a large lipoma arising from the deep layers of the abdominal wall would appear to be excessively rare and the site of origin may be difficult to determine. The CT and MRI appearances of such a tumour are described.

  4. Can abdominal multi-detector CT diagnose spinal osteoporosis?

    Energy Technology Data Exchange (ETDEWEB)

    Papadakis, Antonios E.; Damilakis, John [University of Crete, Department of Medical Physics, Faculty of Medicine, P.O. Box 2208, Iraklion, Crete (Greece); Karantanas, Apostolos H. [University of Crete, Department of Radiology, Faculty of Medicine, P.O. Box 2208, Iraklion, Crete (Greece); Papadokostakis, Giorgos [University Hospital of Heraklion, Department of Orthopedics, Faculty of Medicine, P.O. Box 2208, Iraklion, Crete (Greece); Petinellis, Effie [University Hospital of Heraklion, Department of Radiotherapy, Faculty of Medicine, P.O. Box 2208, Iraklion, Crete (Greece)

    2009-01-15

    The aim of this study was to (1) generate quantitative CT (QCT) densitometric data based on routine abdominal multi-detector (MDCT) examinations and (2) investigate whether these data can be used to differentiate osteoporotic from healthy females. Twenty-five female patients (group A) with a history of radiotherapy were examined both with routine abdominal MDCT and standard QCT to generate a MDCT-to-QCT conversion equation. Twenty-one osteoporotic (group B) and 23 healthy female patients (group C) were also recruited in the study. Patients of groups B and C underwent routine abdominal MDCT examination for various clinical indications. Mean bone mineral density (BMD) in patients of group A was 103.4 mg/ml {+-} 32.8 with routine abdominal MDCT and 91.0 mg/ml {+-}28.5 with QCT. Quantitative CT BMD{sub QCT} values for patients in groups B and C were calculated utilizing the BMD{sub MDCT} values derived from routine abdominal MDCT data sets and the MDCT to QCT conversion equation: BMD{sub QCT}=0.78. BMD{sub MDCT}+10.13. The calculated QCT densitometric data adequately differentiated osteoporotic from healthy females (area under ROC curve 0.828, p=0.05). In conclusion, this study showed that in a group of female patients, QCT data derived from routine abdominal MDCT examinations discriminated osteoporotic from healthy subjects. (orig.)

  5. Chronic respiratory symptoms associated with airway wall thickening measured by thin-slice low-dose CT

    NARCIS (Netherlands)

    Xie, Xueqian; Dijkstra, Akkelies E.; Vonk, Judith M.; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Groen, Harry J. M.

    2014-01-01

    OBJECTIVE: In lung cancer screening, the prevalence of chronic respiratory symptoms is high among heavy smokers. The purpose of this study was to compare CT-derived airway wall measurements between male smokers with and those without chronic respiratory symptoms. MATERIALS AND METHODS: Fifty male

  6. Low-dose CT of the paranasal sinuses with eye lens protection: effect on image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Hein, Eike; Rogalla, Patrik; Klingebiel, Randolph; Hamm, Bernd [Department of Diagnostic and Interventional Radiology, Charite Hospital, Humboldt-Universitaet zu Berlin (Germany)

    2002-07-01

    The purpose of the study was to assess the effect of lens protection on image quality and radiation dose to the eye lenses in CT of the paranasal sinuses. In 127 patients referred to rule out sinusitis, an axial spiral CT with a lens protection placed on the patients eyes was obtained (1.5/2/1, 50 mAs, 120 kV). Coronal views were reconstructed at 5-mm interval. To quantify a subjective impression of image quality, three regions of interest within the eyeball were plotted along a line perpendicular to the protection at 2, 5, and 9 mm beneath skin level on the axial images. Additionally, dose reduction of a bismuth-containing latex shield was measured using a film-dosimetry technique. The average eyeball density was 17.97 HU (SD 3.7 HU). The relative increase in CT density was 180.6 (17.7), 103.3 (11.7), and 53.6 HU (9.2), respectively. There was no diagnostic information loss on axial and coronal views observed. Artifacts were practically invisible on images viewed in a bone window/level setting. The use of the shield reduced skin radiation from 7.5 to 4.5 mGy. The utilization of a radioprotection to the eye lenses in paranasal CT is a suitable and effective means of reducing skin radiation by 40%. (orig.)

  7. Performance of computer-aided detection of pulmonary nodules in low-dose CT: comparison with double reading by nodule volume

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yingru; Vliegenthart, Rozemarijn; Wang, Ying; Ooijen, Peter M.A. van; Oudkerk, Matthijs [University of Groningen/University Medical Center Groningen, Center for Medical Imaging - North East Netherlands, Department of Radiology, P.O. Box 30.001, Groningen (Netherlands); Bock, Geertruida H. de [University of Groningen/University Medical Center Groningen, Department of Epidemiology, P.O. Box 30.001, Groningen (Netherlands); Klaveren, Rob J. van [Lievensberg Hospital, Department of Pulmonology, P.O. Box 135, Bergen op Zoom (Netherlands); Bogoni, Luca [CAD Group, Siemens Medical Solutions USA, Inc., Malvern, PA (United States); Jong, Pim A. de; Mali, Willem P. [University of Utrecht, Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, Utrecht (Netherlands)

    2012-10-15

    To evaluate performance of computer-aided detection (CAD) beyond double reading for pulmonary nodules on low-dose computed tomography (CT) by nodule volume. A total of 400 low-dose chest CT examinations were randomly selected from the NELSON lung cancer screening trial. CTs were evaluated by two independent readers and processed by CAD. A total of 1,667 findings marked by readers and/or CAD were evaluated by a consensus panel of expert chest radiologists. Performance was evaluated by calculating sensitivity of pulmonary nodule detection and number of false positives, by nodule characteristics and volume. According to the screening protocol, 90.9 % of the findings could be excluded from further evaluation, 49.2 % being small nodules (less than 50 mm{sup 3}). Excluding small nodules reduced false-positive detections by CAD from 3.7 to 1.9 per examination. Of 151 findings that needed further evaluation, 33 (21.9 %) were detected by CAD only, one of them being diagnosed as lung cancer the following year. The sensitivity of nodule detection was 78.1 % for double reading and 96.7 % for CAD. A total of 69.7 % of nodules undetected by readers were attached nodules of which 78.3 % were vessel-attached. CAD is valuable in lung cancer screening to improve sensitivity of pulmonary nodule detection beyond double reading, at a low false-positive rate when excluding small nodules. circle Computer-aided detection (CAD) has known advantages for computed tomography (CT). (orig.)

  8. Coronary CT angiography: Comparison of a novel iterative reconstruction with filtered back projection for reconstruction of low-dose CT—Initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Takx, Richard A.P. [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, Maastricht University Medical Centre, Maastricht (Netherlands); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States); Moscariello, Antonio [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, Policlinico Universitario Campus Bio-Medico, Rome (Italy); Das, Marco [Department of Radiology, Maastricht University Medical Centre, Maastricht (Netherlands); Rowe, Garrett [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoenberg, Stefan O.; Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Henzler, Thomas [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

    2013-02-15

    Objective: To prospectively compare subjective and objective image quality in 20% tube current coronary CT angiography (cCTA) datasets between an iterative reconstruction algorithm (SAFIRE) and traditional filtered back projection (FBP). Materials and methods: Twenty patients underwent a prospectively ECG-triggered dual-step cCTA protocol using 2nd generation dual-source CT (DSCT). CT raw data was reconstructed using standard FBP at full-dose (Group{sub 1}a) and 80% tube current reduced low-dose (Group{sub 1}b). The low-dose raw data was additionally reconstructed using iterative raw data reconstruction (Group{sub 2}). Attenuation and image noise were measured in three regions of interest and signal-to-noise-ratio (SNR) as well as contrast-to-noise-ratio (CNR) was calculated. Subjective diagnostic image quality was evaluated using a 4-point Likert scale. Results: Mean image noise of group{sub 2} was lowered by 22% on average when compared to group{sub 1}b (p < 0.0001–0.0033), while there were no significant differences in mean attenuation within the same anatomical regions. The lower image noise resulted in significantly higher SNR and CNR ratios in group{sub 2} compared to group{sub 1}b (p < 0.0001–0.0232). Subjective image quality of group{sub 2} (1.88 ± 0.63) was also rated significantly higher when compared to group{sub 1}b (1.58 ± 0.63, p = 0.004). Conclusions: Image quality of 80% tube current reduced iteratively reconstructed cCTA raw data is significantly improved when compared to standard FBP and consequently may improve the diagnostic accuracy of cCTA.

  9. Emphysema progression is visually detectable in low-dose CT in continuous but not in former smokers

    DEFF Research Database (Denmark)

    Wille, Mathilde Marie Winkler; Thomsen, Laura H.; Dirksen, Asger

    2014-01-01

    OBJECTIVES: To evaluate interobserver agreement and time-trend in chest CT assessment of emphysema, airways, and interstitial abnormalities in a lung cancer screening cohort. METHODS: Visual assessment of baseline and fifth-year examination of 1990 participants was performed independently by two...... time-trends for emphysema presence and grading. • For continuous smokers, progression of emphysema was seen in all lung zones. • For former smokers, progression of emphysema was undetectable by visual assessment. • Onset and progression of interstitial abnormalities are visually detectable....... prevalence and grade of emphysema in late CT examinations). Significant progression in emphysema was seen in continuous smokers, but not in former smokers. Agreement on centrilobular emphysema subtype was substantial; agreement on paraseptal subtype, moderate. Agreement on panlobular and mixed subtypes...

  10. Emphysema progression is visually detectable in low-dose CT in continuous but not in former smokers

    Energy Technology Data Exchange (ETDEWEB)

    Winkler Wille, Mathilde Marie; Thomsen, Laura H.; Dirksen, Asger; Shaker, Saher B. [Gentofte Hospital, Department of Respiratory Medicine, Hellerup (Denmark); Petersen, Jens [Copenhagen University, Department of Computer Science, Copenhagen (Denmark); Pedersen, Jesper Holst [Copenhagen University Hospital, Department of Thoracic Surgery, Rigshospitalet, Copenhagen (Denmark)

    2014-11-15

    To evaluate interobserver agreement and time-trend in chest CT assessment of emphysema, airways, and interstitial abnormalities in a lung cancer screening cohort. Visual assessment of baseline and fifth-year examination of 1990 participants was performed independently by two observers. Results were standardised by means of an electronic score sheet; kappa and time-trend analyses were performed. Interobserver agreement was substantial in early emphysema diagnosis; highly significant (p < 0.001) time-trends in both emphysema presence and grading were found (higher prevalence and grade of emphysema in late CT examinations). Significant progression in emphysema was seen in continuous smokers, but not in former smokers. Agreement on centrilobular emphysema subtype was substantial; agreement on paraseptal subtype, moderate. Agreement on panlobular and mixed subtypes was only fair. Agreement was fair regarding airway analysis. Interstitial abnormalities were infrequent in the cohort, and agreement on these was fair to moderate. A highly significant time-trend was found regarding interstitial abnormalities, which were more frequent in late examinations. Visual scoring of chest CT is able to characterise the presence, pattern, and progression of early emphysema. Continuous smokers progress; former smokers do not. (orig.)

  11. Abdominal CT findings of delayed postoperative complications

    Energy Technology Data Exchange (ETDEWEB)

    Zissin, R.; Osadchy, A. [Sapir Medical Center, Dept. of Diagnostic Imaging, Kfar Saba (Israel)]. E-mail: zisinrivka@clalit.org.il; Gayer, G. [Assaf Harofe Medical Center, Dept. of Diagnostic Imaging, Zrifin (Israel)

    2007-10-15

    Despite progress in surgical techniques and modern medical treatment, postoperative complications occur not infrequently and vary according to type of surgery, clinical setting, and time elapsed since surgery. In general, they can be divided into early and delayed complications. Delayed postoperative complications can be classified as specific and nonspecific. The common nonspecific delayed complications are incisional hernia and postoperative bowel obstruction. Bowel obstruction can be further categorized as obstruction related to benign or neoplastic etiology, the latter occurring in oncology patients in whom the primary surgery was related to an underlying abdominal neoplasm. Gossypiboma is another, fortunately rare, postoperative complication. Specific complications appear after specific operations and include the following: Splenosis - following splenectomy. Retained gallstones and spilled gallstones - following cholecystectomy, mainly laparoscopic. Dropped appendicolith and stump appendicitis - following appendectomy, mainly laparoscopic. Obturation obstruction by a bezoar - following gastric surgery. Afferent loop syndrome (ALS) - following Bilroth II gastrectomy. (author)

  12. SU-E-I-41: Dictionary Learning Based Quantitative Reconstruction for Low-Dose Dual-Energy CT (DECT)

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Q [School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Department of Radiation Oncology, Stanford University, Stanford, CA 94305 (United States); Xing, L [Department of Radiation Oncology, Stanford University, Stanford, CA 94305 (United States); Xiong, G; Elmore, K; Min, J [Dalio Institute of Cardiovascular Imaging, New York-Presbyterian Hospital and Weill Cornell Medical College, New York, NY (United States)

    2015-06-15

    Purpose: DECT collects two sets of projection data under higher and lower energies. With appropriates composition methods on linear attenuation coefficients, quantitative information about the object, such as density, can be obtained. In reality, one of the important problems in DECT is the radiation dose due to doubled scans. This work is aimed at establishing a dictionary learning based reconstruction framework for DECT for improved image quality while reducing the imaging dose. Methods: In our method, two dictionaries were learned respectively from the high-energy and lowenergy image datasets of similar objects under normal dose in advance. The linear attenuation coefficient was decomposed into two basis components with material based composition method. An iterative reconstruction framework was employed. Two basis components were alternately updated with DECT datasets and dictionary learning based sparse constraints. After one updating step under the dataset fidelity constraints, both high-energy and low-energy images can be obtained from the two basis components. Sparse constraints based on the learned dictionaries were applied to the high- and low-energy images to update the two basis components. The iterative calculation continues until a pre-set number of iteration was reached. Results: We evaluated the proposed dictionary learning method with dual energy images collected using a DECT scanner. We re-projected the projection data with added Poisson noise to reflect the low-dose situation. The results obtained by the proposed method were compared with that obtained using FBP based method and TV based method. It was found that the proposed approach yield better results than other methods with higher resolution and less noise. Conclusion: The use of dictionary learned from DECT images under normal dose is valuable and leads to improved results with much lower imaging dose.

  13. Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Joscha, E-mail: joscha.maier@dkfz.de [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)

    2014-05-15

    Purpose: Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. Methods: Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. Results: Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the

  14. Computer and Modernization%Low-dose CT Image Reconstruction Based on Adaptive Kernel Regression Method and Algebraic Reconstruction Technique

    Institute of Scientific and Technical Information of China (English)

    钟志威

    2016-01-01

    针对稀疏角度投影数据CT图像重建问题,TV-ART算法将图像的梯度稀疏先验知识引入代数重建法( ART)中,对分段平滑的图像具有较好的重建效果。但是,该算法在边界重建时会产生阶梯效应,影响重建质量。因此,本文提出自适应核回归函数结合代数重建法的重建算法( LAKR-ART),不仅在边界重建时不会产生阶梯效应,而且对细节纹理重建具有更好的重建效果。最后对shepp-logan标准CT图像和实际CT头颅图像进行仿真实验,并与ART、TV-ART算法进行比较,实验结果表明本文算法有效。%To the problem of sparse angular projection data of CT image reconstruction, TV-ART algorithm introduces the gradient sparse prior knowledge of image to algebraic reconstruction, and the local smooth image gets a better reconstruction effect. How-ever, the algorithm generates step effect when the borders are reconstructed, affecting the quality of the reconstruction. Therefore, this paper proposes an adaptive kernel regression function combined with Algebraic Reconstruction Technique reconstruction algo-rithm ( LAKR-ART) , it does not produce the step effect on the border reconstruction, and has a better effect to detail reconstruc-tion. Finally we use the shepp-logan CT image and the actual CT image to make the simulation experiment, and compare with ART and TV-ART algorithm. The experimental results show the algorithm is of effectiveness.

  15. Low-dose prospective ECG-triggering dual-source CT angiography in infants and children with complex congenital heart disease: first experience

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhaoping; Wang, Ximing; Duan, Yanhua; Wu, Lebin; Wu, Dawei; Chao, Baoting; Liu, Cheng; Xu, Zhuodong [Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Li, Hongxin; Liang, Fei [Shandong Provincial Hospital, Department of Cardiovascular Surgery, Jinan, Shandong (China); Xu, Jian; Chen, Jiuhong [Siemens. Ltd. China, CT Research Collaboration, Beijing (China)

    2010-10-15

    To explore the clinical value of low-dose prospective ECG-triggering dual-source CT (DSCT) angiography in infants and children with complex congenital heart disease (CHD) compared with transthoracic echocardiography (TTE). Thirty-five patients (mean age: 16 months, range: 2 months to 6 years; male 15; mean weight: 12 kg) underwent low-dose prospective ECG-triggering DSCT angiography and TTE. Surgeries were performed in 29 patients, and conventional cardiac angiography (CCA) was performed in 8 patients. The accuracy was calculated based on the surgical and/or CCA findings. The overall imaging quality was evaluated on a five-point scale. A total of 146 separate cardiovascular deformities were confirmed. DSCT missed three atrial septal defects and a patent ductus arteriosus. The accuracy of DSCT angiography and TTE was 97.3% (142/146) and 92.5% (135/146), respectively. Overall test parameters for DSCT angiography and TTE were similar (sensitivity, 97.3% vs 92.5%; specificity, 99.8% vs 99.8%). The average subjective image quality score was 4.3 {+-} 0.7. The mean effective dose was 0.38 {+-} 0.09 mSv. Prospective ECG-triggering DSCT angiography with a very low effective radiation dose allows the accurate diagnosis of anomalies in infants and children with complex CHD compared with TTE. It has great promise to become a commonly used second-line technique for complex CHD. (orig.)

  16. Patient-bounded extrapolation using low-dose priors for volume-of-interest imaging in C-arm CT

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Y.; Maier, A.; Berger, M.; Hornegger, J. [Pattern Recognition Lab, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91058 (Germany); Bauer, S. [Siemens AG, Healthcare Sector, Forchheim 91301 (Germany)

    2015-04-15

    Purpose: Three-dimensional (3D) volume-of-interest (VOI) imaging with C-arm systems provides anatomical information in a predefined 3D target region at a considerably low x-ray dose. However, VOI imaging involves laterally truncated projections from which conventional reconstruction algorithms generally yield images with severe truncation artifacts. Heuristic based extrapolation methods, e.g., water cylinder extrapolation, typically rely on techniques that complete the truncated data by means of a continuity assumption and thus appear to be ad-hoc. It is our goal to improve the image quality of VOI imaging by exploiting existing patient-specific prior information in the workflow. Methods: A necessary initial step prior to a 3D acquisition is to isocenter the patient with respect to the target to be scanned. To this end, low-dose fluoroscopic x-ray acquisitions are usually applied from anterior–posterior (AP) and medio-lateral (ML) views. Based on this, the patient is isocentered by repositioning the table. In this work, we present a patient-bounded extrapolation method that makes use of these noncollimated fluoroscopic images to improve image quality in 3D VOI reconstruction. The algorithm first extracts the 2D patient contours from the noncollimated AP and ML fluoroscopic images. These 2D contours are then combined to estimate a volumetric model of the patient. Forward-projecting the shape of the model at the eventually acquired C-arm rotation views gives the patient boundary information in the projection domain. In this manner, we are in the position to substantially improve image quality by enforcing the extrapolated line profiles to end at the known patient boundaries, derived from the 3D shape model estimate. Results: The proposed method was evaluated on eight clinical datasets with different degrees of truncation. The proposed algorithm achieved a relative root mean square error (rRMSE) of about 1.0% with respect to the reference reconstruction on

  17. Technical feasibility proof for high-resolution low-dose photon-counting CT of the breast

    Energy Technology Data Exchange (ETDEWEB)

    Kalender, Willi A.; Kolditz, Daniel; Lueck, Ferdinand [University of Erlangen-Nuernberg, Institute of Medical Physics (IMP), Erlangen (Germany); CT Imaging GmbH, Erlangen (Germany); Steiding, Christian [University of Erlangen-Nuernberg, Institute of Medical Physics (IMP), Erlangen (Germany); CT Imaging GmbH, Erlangen (Germany); University Hospital of Erlangen, Institute of Radiology, Erlangen (Germany); Ruth, Veikko; Roessler, Ann-Christin [University of Erlangen-Nuernberg, Institute of Medical Physics (IMP), Erlangen (Germany); Wenkel, Evelyn [University Hospital of Erlangen, Institute of Radiology, Erlangen (Germany)

    2017-03-15

    X-ray computed tomography (CT) has been proposed and evaluated multiple times as a potentially alternative method for breast imaging. All efforts shown so far have been criticized and partly disapproved because of their limited spatial resolution and higher patient dose when compared to mammography. Our concept for a dedicated breast CT (BCT) scanner therefore aimed at novel apparatus and detector design to provide high spatial resolution of about 100 μm and average glandular dose (AGD) levels of 5 mGy or below. Photon-counting technology was considered as a solution to reach these goals. The complete concept was previously evaluated and confirmed by simulations and basic experiments on laboratory setups. We here present measurements of dose, technical image quality parameters and surgical specimen results on such a scanner. For comparison purposes, the specimens were also imaged with digital mammography (DM) and breast tomosynthesis (BT) apparatus. Results show that photon-counting BCT (pcBCT) at 5 mGy AGD offers sufficiently high 3D spatial resolution for reliable detectability of calcifications and soft tissue delineation. (orig.)

  18. A very fast iterative algorithm for TV-regularized image reconstruction with applications to low-dose and few-view CT

    CERN Document Server

    Kudo, Hiroyuki; Nemoto, Takuya; Takaki, Keita

    2016-01-01

    This paper concerns iterative reconstruction for low-dose and few-view CT by minimizing a data-fidelity term regularized with the Total Variation (TV) penalty. We propose a very fast iterative algorithm to solve this problem. The algorithm derivation is outlined as follows. First, the original minimization problem is reformulated into the saddle point (primal-dual) problem by using the Lagrangian duality, to which we apply the first-order primal-dual iterative methods. Second, we precondition the iteration formula using the ramp flter of Filtered Backprojection (FBP) reconstruction algorithm in such a way that the problem solution is not altered. The resulting algorithm resembles the structure of so-called iterative FBP algorithm, and it converges to the exact minimizer of cost function very fast.

  19. Differential analgesic effects of low-dose epidural morphine and morphine-bupivacaine at rest and during mobilization after major abdominal surgery

    DEFF Research Database (Denmark)

    Dahl, J B; Rosenberg, J; Hansen, B L

    1992-01-01

    In a double-blind, randomized study, epidural infusions of low-dose morphine (0.2 mg/h) combined with low-dose bupivacaine (10 mg/h) were compared with epidural infusions of low-dose morphine (0.2 mg/h) alone for postoperative analgesia at rest and during mobilization and cough in 24 patients aft....... Evaluation of postoperative analgesic regimens should include assessment of pain during various activities as different analgesics may have differential effects on pain at rest and during mobilization....

  20. Interobserver agreement for the detection of atherosclerotic plaque in coronary CT angiography: comparison of two low-dose image acquisition protocols with standard retrospectively ECG-gated reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Schuhbaeck, Annika; Rixe, Johannes; Hamm, Christian [University of Giessen, Department of Cardiology, Giessen (Germany); Marwan, Mohamed; Gauss, Soeren; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G.; Achenbach, Stephan [University of Erlangen, Department of Cardiology, Erlangen (Germany); Schneider, Christian [University of Giessen, Department of Radiology, Giessen (Germany); Lell, Michael [University of Erlangen, Department of Radiology, Erlangen (Germany)

    2012-07-15

    We compared the interobserver variability concerning the detection of calcified and non-calcified plaque in two different low-dose and standard retrospectively gated protocols for coronary CTA. 150 patients with low heart rates and less than 100 kg body weight were randomised and examined by contrast-enhanced dual-source CT coronary angiography (100 kV, 320 mAs). 50 patients were examined with prospectively ECG-triggered axial acquisition, 50 patients with prospectively ECG-triggered high pitch spiral acquisition, and 50 patients using spiral acquisition with retrospective ECG gating. Two investigators independently analysed the datasets concerning the presence of calcified and non-calcified plaque on a per-segment level. Mean effective dose was 1.4 {+-} 0.2 mSv for axial, 0.8 {+-} 0.07 mSv for high-pitch spiral, and 5.3 {+-} 2.6 mSV for standard spiral acquisition (P < 0.0001). In axial acquisition, interobserver agreement concerning the presence of atherosclerotic plaque was achieved in 650/749 coronary segments (86.8%). In high-pitch spiral acquisition, agreement was achieved in 664/748 segments (88.8%, n.s.). In standard spiral acquisition, agreement was achieved in 672/738 segments (91.0%, P < 0.0001). Interobserver agreement was significantly higher for calcified than for non-calcified plaque in all data acquisition modes. Low-dose coronary CT angiography permits the detection of coronary atherosclerotic plaque with good interobserver agreement. (orig.)

  1. Very low-dose adult whole-body tumor imaging with F-18 FDG PET/CT

    Science.gov (United States)

    Krol, Andrzej; Naveed, Muhammad; McGrath, Mary; Lisi, Michele; Lavalley, Cathy; Feiglin, David

    2015-03-01

    The aim of this study was to evaluate if effective radiation dose due to PET component in adult whole-body tumor imaging with time-of-flight F-18 FDG PET/CT could be significantly reduced. We retrospectively analyzed data for 10 patients with the body mass index ranging from 25 to 50. We simulated F-18 FDG dose reduction to 25% of the ACR recommended dose via reconstruction of simulated shorter acquisition time per bed position scans from the acquired list data. F-18 FDG whole-body scans were reconstructed using time-of-flight OSEM algorithm and advanced system modeling. Two groups of images were obtained: group A with a standard dose of F-18 FDG and standard reconstruction parameters and group B with simulated 25% dose and modified reconstruction parameters, respectively. Three nuclear medicine physicians blinded to the simulated activity independently reviewed the images and compared diagnostic quality of images. Based on the input from the physicians, we selected optimal modified reconstruction parameters for group B. In so obtained images, all the lesions observed in the group A were visible in the group B. The tumor SUV values were different in the group A, as compared to group B, respectively. However, no significant differences were reported in the final interpretation of the images from A and B groups. In conclusion, for a small number of patients, we have demonstrated that F-18 FDG dose reduction to 25% of the ACR recommended dose, accompanied by appropriate modification of the reconstruction parameters provided adequate diagnostic quality of PET images acquired on time-of-flight PET/CT.

  2. The CT features of abdominal tuberculosis in children

    Energy Technology Data Exchange (ETDEWEB)

    Andronikou, Savvas; Welman, Chris J.; Kader, Ebrahim [Department of Paediatric Radiology, Red Cross Children' s Hospital, Rondebosch, Cape Town (South Africa); Institute of Child Health, University of Cape Town (South Africa)

    2002-02-01

    Background: The last decade has seen a resurgence in the incidence and clinical presentation of tuberculosis (TB). Little data exist in the paediatric age group regarding abdominal tuberculosis (ATB) and limited reports of its CT features have been published. Purpose: To elucidate the CT features of ATB in children. Materials and methods: The medical records of 22 patients with ATB were reviewed. Data were extracted regarding the methods of diagnosis and HIV status. The plain chest films were examined and the CT scans were assessed for adenopathy, solid organ involvement, ascites, bowel wall and omental thickening and inflammatory masses. Results: Ten patients had biopsy-proven ATB, 11 had extra-abdominal TB with clinical suspicion of ATB and 1 had a positive trial of therapy. Five patients were tested for HIV and one tested positive. Thirteen patients had abnormal chest radiographs. The commonest CT finding was lymphadenopathy (n=17), followed by solid organ involvement (n=12), ascites (n=5), bowel wall thickening (n=5), inflammatory masses (n=2) and omental thickening (n=1). Conclusions: The clinical features of ATB are protean. This usually results in a delay in diagnosis and impacts negatively on patient morbidity and mortality. On CT, the constellation of findings is highly suggestive of the diagnosis of ATB and, used in conjunction with clinical and laboratory data, should narrow the differential considerably. Unique findings include histologically proven active TB in calcified lymph nodes and a pancreatic TB granuloma. (orig.)

  3. Characteristic performance evaluation of a photon counting Si strip detector for low dose spectral breast CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hyo-Min; Ding, Huanjun; Molloi, Sabee, E-mail: symolloi@uci.edu [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States); Barber, William C.; Iwanczyk, Jan S. [DxRay Inc., Northridge, California 91324 (United States)

    2014-09-15

    Purpose: The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-ray detector based on a silicon (Si) strip sensor used in an edge-on geometry with an application specific integrated circuit to record the number of x-rays and their energies at high flux and fast frame rates. The investigated detector was integrated with a dedicated breast spectral computed tomography (CT) system to make use of the detector's high spatial and energy resolution and low noise performance under conditions suitable for clinical breast imaging. The aim of this article is to investigate the intrinsic characteristics of the detector, in terms of maximum output count rate, spatial and energy resolution, and noise performance of the imaging system. Methods: The maximum output count rate was obtained with a 50 W x-ray tube with a maximum continuous output of 50 kVp at 1.0 mA. A{sup 109}Cd source, with a characteristic x-ray peak at 22 keV from Ag, was used to measure the energy resolution of the detector. The axial plane modulation transfer function (MTF) was measured using a 67 μm diameter tungsten wire. The two-dimensional (2D) noise power spectrum (NPS) was measured using flat field images and noise equivalent quanta (NEQ) were calculated using the MTF and NPS results. The image quality parameters were studied as a function of various radiation doses and reconstruction filters. The one-dimensional (1D) NPS was used to investigate the effect of electronic noise elimination by varying the minimum energy threshold. Results: A maximum output count rate of 100 million counts per second per square millimeter (cps/mm{sup 2}) has been obtained (1 million cps per 100 × 100 μm pixel). The electrical noise floor was less than 4 keV. The

  4. Feasibility of spectral shaping for detection and quantification of coronary calcifications in ultra-low dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Vonder, Marleen; Pelgrim, Gert Jan; Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen (Netherlands); University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen (Netherlands); Huijsse, Sevrin E.M.; Greuter, Marcel J.W. [University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen (Netherlands); Meyer, Mathias; Henzler, Thomas [Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University Medical Center Mannheim, Heidelberg (Germany); Flohr, Thomas G. [Siemens Healthcare GmbH, Computed Tomography, Forchheim (Germany); Oudkerk, Matthijs [University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen (Netherlands)

    2017-05-15

    To evaluate detectability and quantification of coronary calcifications for CT with a tin filter for spectral shaping. Phantom inserts with 100 small and 9 large calcifications, and a moving artificial artery with 3 calcifications (speed 0-30 mm/s) were placed in a thorax phantom simulating different patient sizes. The phantom was scanned in high-pitch spiral mode at 100 kVp with tin filter (Sn100 kVp), and at a reference of 120 kVp, with electrocardiographic (ECG) gating. Detectability and quantification of calcifications were analyzed for standard (130 HU) and adapted thresholds. Sn100 kVp yielded lower detectability of calcifications (9 % versus 12 %, p = 0.027) and lower Agatston scores (p < 0.008), irrespective of calcification, patient size and speed. Volume scores of the moving calcifications for Sn100 kVp at speed 10-30 mm/s were lower (p < 0.001), while mass scores were similar (p = 0.131). For Sn100 kVp with adapted threshold of 117 HU, detectability (p = 1.000) and Agatston score (p > 0.206) were similar to 120 kVp. Spectral shaping resulted in median dose reduction of 62.3 % (range 59.0-73.4 %). Coronary calcium scanning with spectral shaping yields lower detectability of calcifications and lower Agatston scores compared to 120 kVp scanning, for which a HU threshold correction should be developed. (orig.)

  5. Estimation of non-solid lung nodule volume with low-dose CT protocols: effect of reconstruction algorithm and measurement method

    Science.gov (United States)

    Gavrielides, Marios A.; DeFilippo, Gino; Berman, Benjamin P.; Li, Qin; Petrick, Nicholas; Schultz, Kurt; Siegelman, Jenifer

    2017-03-01

    Computed tomography is primarily the modality of choice to assess stability of nonsolid pulmonary nodules (sometimes referred to as ground-glass opacity) for three or more years, with change in size being the primary factor to monitor. Since volume extracted from CT is being examined as a quantitative biomarker of lung nodule size, it is important to examine factors affecting the performance of volumetric CT for this task. More specifically, the effect of reconstruction algorithms and measurement method in the context of low-dose CT protocols has been an under-examined area of research. In this phantom study we assessed volumetric CT with two different measurement methods (model-based and segmentation-based) for nodules with radiodensities of both nonsolid (-800HU and -630HU) and solid (-10HU) nodules, sizes of 5mm and 10mm, and two different shapes (spherical and spiculated). Imaging protocols included CTDIvol typical of screening (1.7mGy) and sub-screening (0.6mGy) scans and different types of reconstruction algorithms across three scanners. Results showed that radio-density was the factor contributing most to overall error based on ANOVA. The choice of reconstruction algorithm or measurement method did not affect substantially the accuracy of measurements; however, measurement method affected repeatability with repeatability coefficients ranging from around 3-5% for the model-based estimator to around 20-30% across reconstruction algorithms for the segmentation-based method. The findings of the study can be valuable toward developing standardized protocols and performance claims for nonsolid nodules.

  6. Adaptive Statistical Iterative Reconstruction-Applied Ultra-Low-Dose CT with Radiography-Comparable Radiation Dose: Usefulness for Lung Nodule Detection.

    Science.gov (United States)

    Yoon, Hyun Jung; Chung, Myung Jin; Hwang, Hye Sun; Moon, Jung Won; Lee, Kyung Soo

    2015-01-01

    To assess the performance of adaptive statistical iterative reconstruction (ASIR)-applied ultra-low-dose CT (ULDCT) in detecting small lung nodules. Thirty patients underwent both ULDCT and standard dose CT (SCT). After determining the reference standard nodules, five observers, blinded to the reference standard reading results, independently evaluated SCT and both subsets of ASIR- and filtered back projection (FBP)-driven ULDCT images. Data assessed by observers were compared statistically. Converted effective doses in SCT and ULDCT were 2.81 ± 0.92 and 0.17 ± 0.02 mSv, respectively. A total of 114 lung nodules were detected on SCT as a standard reference. There was no statistically significant difference in sensitivity between ASIR-driven ULDCT and SCT for three out of the five observers (p = 0.678, 0.735, Adaptive statistical iterative reconstruction-driven ULDCT delivering a radiation dose of only 0.17 mSv offers acceptable sensitivity in nodule detection compared with SCT and has better performance than FBP-driven ULDCT.

  7. Using Abdominal CT Data for Visceral Fat Evaluation

    Directory of Open Access Journals (Sweden)

    M Pop

    2013-10-01

    Full Text Available Background: Quantitative assessment of body fat is important for the diagnosis and treatment of diseases related to obesity, Computed tomography (CT becoming the standard procedure for measuring the abdominal fat distribution. Material and method: The retrospective study included 111 inpatients, who underwent routine abdominal CT exams in the Radiology Laboratory of SCJU Tg.Mures (2013. MPR MDCT (SOMATOM AS 64 data was processed using a custom written MATLAB R2009b software, ImageJ being used for tracing of the visceral fat area (VFA. Patient data (including blood glucose, cholesterol and triglycerides were analyzed using MO Excel and GraphPad Inprism5. Results: Visceral Fat percentage varied in population from 14.59-68.69 (SD = 11.83 with significant difference between sexes (male vs. female, 46.98 vs. 31.62, p 220 mg% and triglycerides >150 mg% are significantly associated with the VF percent (p <0.05. Overall there is a weak correlation between the lab variables and the measured fat, the strongest one being between triglycerides and the VFA (r = +0.23 and between age and VFA percentage (certain samples. Conclusions: The technique used should decreases the human error in marking of the fat areas providing a better estimation of the VF/VF percentage. CT measured VF relates with certain lab tests. Further analysis, is required for a better use of CT in obesity related pathology diagnosis and treatment

  8. Lung nodule detection performance in five observers on computed tomography (CT) with adaptive iterative dose reduction using three-dimensional processing (AIDR 3D) in a Japanese multicenter study: Comparison between ultra-low-dose CT and low-dose CT by receiver-operating characteristic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nagatani, Yukihiro, E-mail: yatsushi@belle.shiga-med.ac.jp [Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga (Japan); Takahashi, Masashi; Murata, Kiyoshi [Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga (Japan); Ikeda, Mitsuru [Department of Radiological and Medical Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Aichi (Japan); Yamashiro, Tsuneo [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan); Miyara, Tetsuhiro [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan); Department of Radiology, Okinawa Prefectural Yaeyama Hospital, Ishigaki 907-0022, Okinawa (Japan); Koyama, Hisanobu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo (Japan); Koyama, Mitsuhiro [Department of Radiology, Osaka Medical College, Takatsuki 569-8686, Osaka (Japan); Sato, Yukihisa [Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka (Japan); Department of Radiology, Osaka Medical Center of Cancer and Cardiovascular Diseases, Osaka 537-8511, Osaka (Japan); Moriya, Hiroshi [Department of Radiology, Ohara General Hospital, Fukushima 960-8611 (Japan); Noma, Satoshi [Department of Radiology, Tenri Hospital, Tenri 632-8552, Nara (Japan); Tomiyama, Noriyuki [Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka (Japan); Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo (Japan); Murayama, Sadayuki [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa (Japan)

    2015-07-15

    Highlights: • Using AIDR 3D, ULDCT showed comparable LND of solid nodules to LDCT. • Using AIDR 3D, LND of smaller GGN in ULDCT was inferior to that in LDCT. • Effective dose in ULDCT was about only twice of that in chest X-ray. • BMI values in study population were mostly in the normal range body habitus. - Abstract: Purpose: To compare lung nodule detection performance (LNDP) in computed tomography (CT) with adaptive iterative dose reduction using three dimensional processing (AIDR3D) between ultra-low dose CT (ULDCT) and low dose CT (LDCT). Materials and methods: This was part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases (ACTIve) Study, a multicenter research project being conducted in Japan. Institutional Review Board approved this study and informed consent was obtained. Eighty-three subjects (body mass index, 23.3 ± 3.2) underwent chest CT at 6 institutions using identical scanners and protocols. In a single visit, each subject was scanned using different tube currents: 240, 120 and 20 mA (3.52, 1.74 and 0.29 mSv, respectively). Axial CT images with 2-mm thickness/increment were reconstructed using AIDR3D. Standard of reference (SOR) was determined based on CT images at 240 mA by consensus reading of 2 board-certificated radiologists as to the presence of lung nodules with the longest diameter (LD) of more than 3 mm. Another 5 radiologists independently assessed and recorded presence/absence of lung nodules and their locations by continuously-distributed rating in CT images at 20 mA (ULDCT) and 120 mA (LDCT). Receiver-operating characteristic (ROC) analysis was used to evaluate LNDP of both methods in total and also in subgroups classified by LD (>4, 6 and 8 mm) and nodular characteristics (solid and ground glass nodules). Results: For SOR, 161 solid and 60 ground glass nodules were identified. No significant difference in LNDP for entire solid nodules was demonstrated between both methods, as area under ROC

  9. Ultra-low-dose dual-source CT coronary angiography with high pitch: diagnostic yield of a volumetric planning scan and effects on dose reduction and imaging strategy

    Science.gov (United States)

    Hamm, B; Huppertz, A; Lembcke, A

    2015-01-01

    Objective: To evaluate the role of an ultra-low-dose dual-source CT coronary angiography (CTCA) scan with high pitch for delimiting the range of the subsequent standard CTCA scan. Methods: 30 patients with an indication for CTCA were prospectively examined using a two-scan dual-source CTCA protocol (2.0 × 64.0 × 0.6 mm; pitch, 3.4; rotation time of 280 ms; 100 kV): Scan 1 was acquired with one-fifth of the tube current suggested by the automatic exposure control software [CareDose 4D™ (Siemens Healthcare, Erlangen, Germany) using 100 kV and 370 mAs as a reference] with the scan length from the tracheal bifurcation to the diaphragmatic border. Scan 2 was acquired with standard tube current extending with reduced scan length based on Scan 1. Nine central coronary artery segments were analysed qualitatively on both scans. Results: Scan 2 (105.1 ± 10.1 mm) was significantly shorter than Scan 1 (127.0 ± 8.7 mm). Image quality scores were significantly better for Scan 2. However, in 5 of 6 (83%) patients with stenotic coronary artery disease, a stenosis was already detected in Scan 1 and in 13 of 24 (54%) patients with non-stenotic coronary arteries, a stenosis was already excluded by Scan 1. Using Scan 2 as reference, the positive- and negative-predictive value of Scan 1 was 83% (5 of 6 patients) and 100% (13 of 13 patients), respectively. Conclusion: An ultra-low-dose CTCA planning scan enables a reliable scan length reduction of the following standard CTCA scan and allows for correct diagnosis in a substantial proportion of patients. Advances in knowledge: Further dose reductions are possible owing to a change in the individual patient's imaging strategy as a prior ultra-low-dose CTCA scan may already rule out the presence of a stenosis or may lead to a direct transferal to an invasive catheter procedure. PMID:25710210

  10. Low-dose ECG-gated 64-slices helical CT angiography of the chest: evaluation of image quality in 105 patients

    Energy Technology Data Exchange (ETDEWEB)

    D' Agostino, A.G.; Remy-Jardin, M.; Khalil, C.; Remy, J. [University Center of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Delannoy-Deken, V.; Duhamel, A. [University of Lille, Department of Medical Statistics, Lille (France); Flohr, T. [Siemens Medical, Research and Development Department, CT Division, Forchheim (Germany)

    2006-10-15

    The purpose of this study was to evaluate image quality of low-dose electrocardiogram (ECG)-gated multislice helical computed tomography (CT) angiograms of the chest. One hundred and five consecutive patients with a regular sinus rhythm (72 men; 33 women) underwent ECG-gated CT angiographic examination of the chest without administration of beta blockers using the following parameters: (a) collimation 32 x 0.6 mm with z-flying focal spot for the acquisition of 64 overlapping 0.6-mm slices, rotation time 0.33 s, pitch 0.3; (b) 120 kV, 200 mAs; (c) use of two dose modulation systems, including adjustment of the mAs setting to the patient's size and anatomical shape and an ECG-controlled tube current. Subjective and objective image quality was evaluated by two radiologists in consensus on 3-mm-thick scans reconstructed at 55% of the response rate (RR) interval. The population and protocol characteristics included: (a) a mean [{+-}standard deviation (SD)] body mass index (BMI) of 24.47 ({+-}4.64); (b) a mean ({+-}SD) heart rate of 72.04 ({+-}15.76) bpm; (c) a mean ({+-}SD) scanning time of 18.3 ({+-}2.73) s; (d) a mean ({+-}SD) dose-length product (DLP) value of 260.57 ({+-}83.67) mGy/cm; (e) an estimated average effective dose of 4.95 ({+-}1.59) mSv. Subjective noise was depicted in a total of nine examinations (8.5%), always rated as mild. Objective noise was assessed by measuring the standard deviation of pixel values in a homogeneous region of interest within the trachea and descending aorta; SD was 15.91 HU in the trachea and 22.16 HU in the descending aorta, with no significant difference in the mean value of the standard deviations between the four categories of BMI except for obese patients, who had a higher mean SD within the aorta. Interpolation artefacts were depicted in 22 patients, with a mean heart rate significantly lower than that of patients without interpolation artifacts, rated as mild in 11 patients and severe in 11 patients. The severity of

  11. Development of automated quantification of visceral and subcutaneous adipose tissue volumes from abdominal CT scans

    Science.gov (United States)

    Mensink, Sanne D.; Spliethoff, Jarich W.; Belder, Ruben; Klaase, Joost M.; Bezooijen, Roland; Slump, Cornelis H.

    2011-03-01

    This contribution describes a novel algorithm for the automated quantification of visceral and subcutaneous adipose tissue volumes from abdominal CT scans of patients referred for colorectal resection. Visceral and subcutaneous adipose tissue volumes can accurately be measured with errors of 1.2 and 0.5%, respectively. Also the reproducibility of CT measurements is good; a disadvantage is the amount of radiation. In this study the diagnostic CT scans in the work - up of (colorectal) cancer were used. This implied no extra radiation. For the purpose of segmentation alone, a low dose protocol can be applied. Obesity is a well known risk factor for complications in and after surgery. Body Mass Index (BMI) is a widely accepted indicator of obesity, but it is not specific for risk assessment of colorectal surgery. We report on an automated method to quantify visceral and subcutaneous adipose tissue volumes as a basic step in a clinical research project concerning preoperative risk assessment. The outcomes are to be correlated with the surgery results. The hypothesis is that the balance between visceral and subcutaneous adipose tissue together with the presence of calcifications in the major bloodvessels, is a predictive indicator for post - operatieve complications such as anastomotic leak. We start with four different computer simulated humanoid abdominal volumes with tissue values in the appropriate Hounsfield range at different dose levels. With satisfactory numerical results for this test, we have applied the algorithm on over a 100 patient scans and have compared results with manual segmentations by an expert for a smaller pilot group. The results are within a 5% difference. Compared to other studies reported in the literature, reliable values are obtained for visceral and subcutaneous adipose tissue areas.

  12. Low-dose dynamic myocardial perfusion CT image reconstruction using pre-contrast normal-dose CT scan induced structure tensor total variation regularization

    Science.gov (United States)

    Gong, Changfei; Han, Ce; Gan, Guanghui; Deng, Zhenxiang; Zhou, Yongqiang; Yi, Jinling; Zheng, Xiaomin; Xie, Congying; Jin, Xiance

    2017-04-01

    Dynamic myocardial perfusion CT (DMP-CT) imaging provides quantitative functional information for diagnosis and risk stratification of coronary artery disease by calculating myocardial perfusion hemodynamic parameter (MPHP) maps. However, the level of radiation delivered by dynamic sequential scan protocol can be potentially high. The purpose of this work is to develop a pre-contrast normal-dose scan induced structure tensor total variation regularization based on the penalized weighted least-squares (PWLS) criteria to improve the image quality of DMP-CT with a low-mAs CT acquisition. For simplicity, the present approach was termed as ‘PWLS-ndiSTV’. Specifically, the ndiSTV regularization takes into account the spatial-temporal structure information of DMP-CT data and further exploits the higher order derivatives of the objective images to enhance denoising performance. Subsequently, an effective optimization algorithm based on the split-Bregman approach was adopted to minimize the associative objective function. Evaluations with modified dynamic XCAT phantom and preclinical porcine datasets have demonstrated that the proposed PWLS-ndiSTV approach can achieve promising gains over other existing approaches in terms of noise-induced artifacts mitigation, edge details preservation, and accurate MPHP maps calculation.

  13. 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.)

  14. Quantitative assessment of first-pass perfusion using a low-dose method at multidetector CT in oesophageal squamous cell carcinoma: Correlation with VEGF expression

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.-W. [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China) and Sichuan Province Key Laboratory of Medical Imaging and Department of Radiology, Affiliated Hospital of North Sichuan Medical College, 63 Wen Hua Lu, Nanchong, Sichuan 637000 (China); Yang, Z.-G., E-mail: yangzg1117@yahoo.com.cn [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Chen, H.-J. [Department of Pathology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Li, Y.; Tang, S.-S.; Yao, J.; Dong, Z.-H. [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); He, D. [Department of Pathology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2012-08-15

    Aim: To investigate the correlation between vascular endothelial cell growth factor (VEGF) expression and first-pass perfusion parameters at multidetector computed tomography (MDCT) using a low-dose technique, and to determine how to discriminate VEGF positivity from VEGF negativity by perfusion CT in oesophageal squamous cell carcinomas. Materials and methods: Thirty-two patients with oesophageal squamous cell carcinomas underwent first-pass perfusion with 64-section MDCT at 50 mAs. Perfusion parameters, including perfusion, peak enhanced density (PED), time to peak (TTP), and blood volume (BV), were measured. Postoperative specimens were assessed for VEGF expression. Correlation tests were performed to determine the associations between each CT perfusion parameter and VEGF expression. The cut-off values of perfusion parameters were obtained statistically to discriminate VEGF positivity from VEGF negativity. Results: Mean perfusion, PED, TTP, and BV were 38.47 {+-} 30.26 ml/min/ml, 24.68 {+-} 9.65 HU, 28.35 {+-} 9.03 s, and 11.82 {+-} 6.06 ml/100 g, respectively. PED or BV were significantly higher in the VEGF-positive group than in the VEGF-negative group (all p < 0.05), but no significant difference in perfusion or TTP was found between the VEGF-positive and VEGF-negative groups (all p > 0.05). In VEGF positivity, PED and BV were correlated with VEGF expression (r = 0.576 and 0.765, respectively; all p < 0.05), whereas perfusion and TTP were not (r = 0.361 and 0.239, respectively; all p > 0.05). A threshold of BV (10.23 ml/100 g) achieved a sensitivity of 94.4%, and a specificity of 92.9% for discriminating VEGF positivity from VEGF negativity. Conclusion: BV could reflect tumour VEGF expression, and could be an indicator for evaluating angiogenesis in oesophageal tumours.

  15. Reliable categorisation of visual scoring of coronary artery calcification on low-dose CT for lung cancer screening: validation with the standard Agatston score

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yi-Luan; Wu, Fu-Zong; Wang, Yen-Chi [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung 813 (China); National Yang Ming University, Faculty of Medicine, School of Medicine, Taipei (China); Ju, Yu-Jeng [National Taiwan University, Department of Psychology, Taipei (China); Mar, Guang-Yuan [Kaohsiung Veterans General Hospital, Division of Cardiology, Department of Medicine, Kaohsiung 813 (China); Chuo, Chiung-Chen [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung 813 (China); Lin, Huey-Shyan [Fooyin University, School of Nursing, Kaohsiung (China); Wu, Ming-Ting [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung 813 (China); National Yang Ming University, Faculty of Medicine, School of Medicine, Taipei (China); National Yang Ming University, Institute of Clinical Medicine, Taipei (China)

    2013-05-15

    To validate the reliability of the visual coronary artery calcification score (VCACS) on low-dose CT (LDCT) for concurrent screening of CAC and lung cancer. We enrolled 401 subjects receiving LDCT for lung cancer screening and ECG-gated CT for the Agatston score (AS). LDCT was reconstructed with 3- and 5-mm slice thickness (LDCT-3mm and LDCT-5mm respectively) for VCACS to obtain VCACS-3mm and VCACS-5mm respectively. After a training session comprising 32 cases, two observers performed four-scale VCACS (absent, mild, moderate, severe) of 369 data sets independently, the results were compared with four-scale AS (0, 1-100, 101-400, >400). CACs were present in 39.6 % (146/369) of subjects. The sensitivity of VCACS-3mm was higher than for VCACS-5mm (83.6 % versus 74.0 %). The median of AS of the 24 false-negative cases in VCACS-3mm was 2.3 (range 1.1-21.1). The false-negative rate for detecting AS {>=} 10 on LDCT-3mm was 1.9 %. VCACS-3mm had higher concordance with AS than VCACS-5mm (k = 0.813 versus k = 0.685). An extended test of VCACS-3mm for four junior observers showed high inter-observer reliability (intra-class correlation = 0.90) and good concordance with AS (k = 0.662-0.747). This study validated the reliability of VCACS on LDCT for lung cancer screening and showed that LDCT-3mm was more feasible than LDCT-5mm for CAD risk stratification. (orig.)

  16. High quality high spatial resolution functional classification in low dose dynamic CT perfusion using singular value decomposition (SVD) and k-means clustering

    Science.gov (United States)

    Pisana, Francesco; Henzler, Thomas; Schönberg, Stefan; Klotz, Ernst; Schmidt, Bernhard; Kachelrieß, Marc

    2017-03-01

    Dynamic CT perfusion acquisitions are intrinsically high-dose examinations, due to repeated scanning. To keep radiation dose under control, relatively noisy images are acquired. Noise is then further enhanced during the extraction of functional parameters from the post-processing of the time attenuation curves of the voxels (TACs) and normally some smoothing filter needs to be employed to better visualize any perfusion abnormality, but sacrificing spatial resolution. In this study we propose a new method to detect perfusion abnormalities keeping both high spatial resolution and high CNR. To do this we first perform the singular value decomposition (SVD) of the original noisy spatial temporal data matrix to extract basis functions of the TACs. Then we iteratively cluster the voxels based on a smoothed version of the three most significant singular vectors. Finally, we create high spatial resolution 3D volumes where to each voxel is assigned a distance from the centroid of each cluster, showing how functionally similar each voxel is compared to the others. The method was tested on three noisy clinical datasets: one brain perfusion case with an occlusion in the left internal carotid, one healthy brain perfusion case, and one liver case with an enhancing lesion. Our method successfully detected all perfusion abnormalities with higher spatial precision when compared to the functional maps obtained with a commercially available software. We conclude this method might be employed to have a rapid qualitative indication of functional abnormalities in low dose dynamic CT perfusion datasets. The method seems to be very robust with respect to both spatial and temporal noise and does not require any special a priori assumption. While being more robust respect to noise and with higher spatial resolution and CNR when compared to the functional maps, our method is not quantitative and a potential usage in clinical routine could be as a second reader to assist in the maps

  17. Abdominal CT scanning in critically ill surgical patients.

    Science.gov (United States)

    Norwood, S H; Civetta, J M

    1985-01-01

    Clinical parameters, intensive care unit (ICU) course, abdominal computed tomography (CT) scans, and the clinical decisions of 53 critically ill patients were reviewed to determine the influence of the CT scan. No scans were positive before the eighth day. Sensitivity was 48% and specificity, 64%. Seventeen (23%) scans of the 72 provided beneficial results: eight localized abscesses that were drained; nine were negative and not operated on. Five (7%) scans provided detrimental information: scan negative with abscess discovered or scan positive but negative laparotomy. Fifty (70%) scans were either of no help or not used in management. The mortality rate was 50% when CT led to an intervention, and 47% in the entire group. Hospital charges were +33,408. Personnel time and cost were 497 hours and +3658; of the total +37,066, 77% (+28,541) could be considered wasted. From these data, it was concluded that CT scans should be used to confirm abscesses, not to search for a source of sepsis. PMID:4015222

  18. Application Analysis of Low Dose Chest CT scan%低剂量胸部CT扫描技术的应用分析

    Institute of Scientific and Technical Information of China (English)

    李晶; 周珏榕; 黄雨琴; 续晋铭; 钱琳琳

    2013-01-01

    Objective To probe into the value of low dose chest CT in clinical application. Methods 100 cases are randomly classified into 2 groups. Each includes 18 males and 32 females. The height is between 1.60~1.78 m and the weight is between 50~80 kg. The tube current of regular group A is 90 mAs, and control group B is 70 mAs. The tube voltages are both 120 Kv and the scanned images are compared by using t test and are supervised by 2 advanced doctors for blind peer review between the two groups. Results CTDI decreases by 23.3%, from 6.84 mGy to 5.32 mGy when the tube current changed from 90 mAs to 70 mAs. The average effective tube ball dose, total tube ball dose, and CT dose index volume are (75.83±4.92) mAs, (2092±128.14) mAs and (5.77±0.42) mGy in regular group A, and the data are (56.24±5.87) mAs, (1592±114.02) mAs and (4.29±0.69) mGy in low dose group. Both of them have statistical significance (t=20.62, t=35.41, t=5.48,p < 0.05). The image noises are (11.4±2.97) HU in standard group and (14.22±3.39) HU in low dose group, there is statistical significance is (t=6.71,p < 0.05 ). Conclusion The low dose chest CT can remarkably reduce the radiation dose, and provide satisfactory images for diagnosis.%目的 探讨低剂量CT胸部扫描技术的临床应用价值.方法 将100例患者随机分2组,各50例,均为男18例,女32例.身高1.60~1.78 m,体重50~80 kg.常规A组采用管电流90 mAs,对照B组管电流70 mAs.管电压均为120 kV,两组胸部扫描的差异对比采用t 检验进行比较.扫描图像质量由2名高年资诊断医师进行盲审.结果 两组对比单次扫描剂量CTDI分别为6.84 mGy、5.32 mGy,降幅为23.3%.常规组的平均有效管球剂量、总管球剂量和放射容积剂量指数分别为(75.83±4.92)mAs、(2092±128.14)mAs和(5.77±0.42)mGy.低剂量组分别为(56.24±5.87)mAs、(1592±114.02)mAs和(4.29±0.69)mGy,两者差异有统计学意义(t =20.62,t =35.41,t =5.48,p <0.05).常规组的图像噪声为(11.4

  19. Diagnostic work-up of pulmonary nodules. Management of pulmonary nodules detected with low-dose CT screening; Abklaerung von Lungenrundherden. Management durch Frueherkennungsuntersuchungen detektierter pulmonaler Rundherde

    Energy Technology Data Exchange (ETDEWEB)

    Wormanns, D. [Evangelische Lungenklinik Berlin, Berlin (Germany)

    2016-09-15

    Pulmonary nodules are the most frequent pathological finding in low-dose computed tomography (CT) scanning for early detection of lung cancer. Early stages of lung cancer are often manifested as pulmonary nodules; however, the very commonly occurring small nodules are predominantly benign. These benign nodules are responsible for the high percentage of false positive test results in screening studies. Appropriate diagnostic algorithms are necessary to reduce false positive screening results and to improve the specificity of lung cancer screening. Such algorithms are based on some of the basic principles comprehensively described in this article. Firstly, the diameter of nodules allows a differentiation between large (>8 mm) probably malignant and small (<8 mm) probably benign nodules. Secondly, some morphological features of pulmonary nodules in CT can prove their benign nature. Thirdly, growth of small nodules is the best non-invasive predictor of malignancy and is utilized as a trigger for further diagnostic work-up. Non-invasive testing using positron emission tomography (PET) and contrast enhancement as well as invasive diagnostic tests (e.g. various procedures for cytological and histological diagnostics) are briefly described in this article. Different nodule morphology using CT (e.g. solid and semisolid nodules) is associated with different biological behavior and different algorithms for follow-up are required. Currently, no obligatory algorithm is available in German-speaking countries for the management of pulmonary nodules, which reflects the current state of knowledge. The main features of some international and American recommendations are briefly presented in this article from which conclusions for the daily clinical use are derived. (orig.) [German] Lungenrundherde sind die haeufigsten pathologischen Befunde bei Untersuchungen mit der Niedrigdosis-CT zur Lungenkrebsfrueherkennung. Fruehstadien des Lungenkarzinoms manifestieren sich meist als Rundherd

  20. Detection of pulmonary embolism with combined ventilation-perfusion SPECT and low-dose CT: head-to-head comparison with multidetector CT angiography

    DEFF Research Database (Denmark)

    Gutte, Henrik; Mortensen, Jann; Jensen, Claus Verner

    2009-01-01

    The diagnosis of pulmonary embolism (PE) is usually established by a combination of clinical assessment, D-dimer testing, and imaging with either pulmonary ventilation-perfusion (V/Q) scintigraphy or pulmonary multidetector CT (MDCT) angiography. Both V/Q SPECT and MDCT angiography seem to have...... high diagnostic accuracy. However, only limited data directly comparing these 2 modalities are available. Hybrid gamma-camera/MDCT systems have been introduced and allow simultaneous 3-dimensional lung V/Q SPECT and MDCT angiography, suitable for diagnosing PE. The aim of our study was to compare...

  1. Spleen volume on CT and the effect of abdominal trauma.

    Science.gov (United States)

    Cruz-Romero, Cinthia; Agarwal, Sheela; Abujudeh, Hani H; Thrall, James; Hahn, Peter F

    2016-08-01

    The aim of this study is to determine the magnitude of change in spleen volume on CT in subjects sustaining blunt abdominal trauma without hemorrhage relative to patients without disease and how the spleen volumes are distributed. Sixty-seven subjects with blunt abdominal trauma and 101 control subjects were included in this retrospective single-center, IRB-approved, and HIPAA-compliant study. Patients with an injured spleen were excluded. Using a semiautomatic segmentation program, two readers computed spleen volumes from CT. Spleen volume distribution in male and female trauma and control cohorts were compared nonparametrically. Spleen volume plotted against height, weight, and age were analyzed by linear regression. The number of females and males are, respectively, 35 and 32 in trauma subjects and 69 and 32 among controls. Female trauma patients (49.6 years) were older than males (39.8 years) (p = 0.02). Distributions of spleen volume were not normal, skewed above their means, requiring a nonparametric comparison. Spleen volumes in trauma patients were smaller than those in controls with medians of 230 vs 294 mL in males(p volume correlated positively with weight in females and with height in male controls, and negatively with age in male controls (p volume in controls was 245 mL, the largest ever reported. Spleen volume decreases in response to blunt abdominal trauma. Spleen volumes are not normally distributed. Our population has the largest spleen volume reported in the literature, perhaps a consequence of the obesity epidemic.

  2. Blunt abdominal trauma: The role of focused abdominal sonography in assessment of organ injury and reducing the need for CT

    Directory of Open Access Journals (Sweden)

    Samer Malak Boutros

    2016-03-01

    Conclusion: Ultrasonography is considered the best modality in initial evaluation of blunt abdominal trauma patients as it is noninvasive, readily available, and requires minimal preparation time. Ultrasonography is very useful in follow up of patients with intra-abdominal injury and decreases use of CT which has the disadvantages of being expensive, high dose radiation.

  3. Identification of early-stage usual interstitial pneumonia from low-dose chest CT scans using fractional high-density lung distribution

    Science.gov (United States)

    Xie, Yiting; Salvatore, Mary; Liu, Shuang; Jirapatnakul, Artit; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2017-03-01

    A fully-automated computer algorithm has been developed to identify early-stage Usual Interstitial Pneumonia (UIP) using features computed from low-dose CT scans. In each scan, the pre-segmented lung region is divided into N subsections (N = 1, 8, 27, 64) by separating the lung from anterior/posterior, left/right and superior/inferior in 3D space. Each subsection has approximately the same volume. In each subsection, a classic density measurement (fractional high-density volume h) is evaluated to characterize the disease severity in that subsection, resulting in a feature vector of length N for each lung. Features are then combined in two different ways: concatenation (2*N features) and taking the maximum in each of the two corresponding subsections in the two lungs (N features). The algorithm was evaluated on a dataset consisting of 51 UIP and 56 normal cases, a combined feature vector was computed for each case and an SVM classifier (RBF kernel) was used to classify them into UIP or normal using ten-fold cross validation. A receiver operating characteristic (ROC) area under the curve (AUC) was used for evaluation. The highest AUC of 0.95 was achieved by using concatenated features and an N of 27. Using lung partition (N = 27, 64) with concatenated features had significantly better result over not using partitions (N = 1) (p-value < 0.05). Therefore this equal-volume partition fractional high-density volume method is useful in distinguishing early-stage UIP from normal cases.

  4. Application of low-dose 16-slice spiral CT scanning technology in adenoidal hypertrophy in children%16层螺旋CT低剂量扫描技术在儿童腺样体肥大中的应用

    Institute of Scientific and Technical Information of China (English)

    党保华; 曲金荣; 张建伟; 刘翠翠; 黎海亮

    2012-01-01

    目的:探讨16层螺旋CT低剂量扫描技术在儿童腺样体肥大的临床应用.方法:对46例临床疑似腺样体肥大儿童行16层螺旋CT低剂量和常规剂量扫描,将其随机分为两组,时比两种剂量扫描的图像质量与患者的辐射剂量.结果:16层螺旋CT低剂量扫描与常规剂量扫描对显示鼻咽部的解剖结构及病变差异无显著性意义(P=0.381).对低剂量组/常规剂量组两组腺样体CT值平均值之间无统计学差异(P=0.256).CT值标准偏差之间无统计学差异(P=0.313).低剂量CT扫描显示儿童鼻咽部扫描参数中CTDIvol为4.35 mGy、DLP为40.62 mGy·cm,常规剂量CTDIvol为8.65 mGy、DLP为81.23 mGy·cm.低剂量与常规剂量相比,其CTDIvol和DLP降低了约50%的辐射剂量.结论:16层螺旋CT低剂量扫描对腺样体肥大的诊断结果与常规剂量均相同,故16层螺旋CT低剂量扫描临床疑似腺样体肥大的患者,完全能替代常规剂量的16层螺旋CT扫描.%Objective:To investigate clinical application value of low-dose 16-slice spiral CT scanning technology in the adenoidal hypertrophy of children. MethodS:46 cases of children with adenoidal hypertrophy underwent low-dose (group A) and conventional-dose (group B) 16-slice spiral CT scanning. The image quality and radiation dose in two groups were compared. Results: The display of the anatomical structure of the nasopharynx and adenoidal hypertrophy showed no significant difference between low-dose CT scanning and conventional-dose CT scanning (P = 0. 381). It showed no significant difference in the mean of CT values (P=0. 256) and the standard deviation of CT values (P=0. 313) between low-dose and conventional-dose scanning. The CTDIvol of low-dose CT scanning was 4. 35mGy,and DLP was40. 62mGy ·cm,and the CTDIvol of conventional doses was 8. 65mGy,DLP was 81. 23mGy-cm. The CTDIvol and DLP of low-dose CT scanning decreased about 50% as compared with those of conventional dose scanning. Conclusion

  5. Observer variation in vascular CT measurements of the abdominal aorta

    Energy Technology Data Exchange (ETDEWEB)

    England, Andrew [Department of Radiology, South Manchester University Hospitals NHS Trust, Southmoor Road, Manchester M23 9LT (United Kingdom); Department of Medical Imaging and Radiotherapy, University of Liverpool, Johnson Building, Quadrangle, Brownlow Hill, Liverpool L69 3GB (United Kingdom)], E-mail: a.england@liverpool.ac.uk; Butterfield, John S.; Ashleigh, Raymond J. [Department of Radiology, South Manchester University Hospitals NHS Trust, Southmoor Road, Manchester M23 9LT (United Kingdom)

    2008-11-15

    Aim: To assess the inter-observer variation between a radiographer and radiologist when performing CT measurement of the abdominal aorta before endovascular aortic aneurysm repair (EVAR). Methods: A total of 30 consecutive patients who were considered anatomically suitable for EVAR had aortic measurements performed independently by a vascular radioogist and then by a radiographer training vascular and CT imaging. All measurements were performed on a computer workstation using electronic callipers, each patient had 12 anatomical sites evaluated (eight diameters, four vessel lengths). Statistical analysis was performed by the computer package SPSS for Windows 11.01. Results: Of the 30 patients, mean difference in measurements between observers was 2.3 mm {+-} 1.2 mm and 6.0 mm {+-} 6.4 mm for diameter and vessel length measurements, respectively. Two hundred and seven (86%) diameter measurements were {<=}2 mm of each other and 233 (97%) were within {<=}5 mm. Eighty-two (57%) length measurements were within {<=}5 mm, and 100 (83%) within 10 mm or less. Widest variation existed for measurements of common iliac diameter and aortic neck length, where coefficients of variance were 38.2 (95% CI 35.7-41.0) and 40.0 (95% CI 36.2-44.6), respectively. Conclusion: A good level of agreement exists between a trained radiographer and radiologist when comparing vascular CT measurements of the aorta. It is technically feasible for a radiographer to perform these measurements, and improvements in variability may be achieved from a more standardised technique and automated vessel analysis software. Further research is required to establish the overall variability between different observer types when undertaking vascular CT measurements.

  6. Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

    Energy Technology Data Exchange (ETDEWEB)

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Otrakji, Alexi; Padole, Atul; Lim, Ruth; Nimkin, Katherine; Westra, Sjirk; Kalra, Mannudeep K.; Gee, Michael S. [MGH Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

    2015-07-15

    Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT. (orig.)

  7. SPECT/spiral CT and bone scintigraphy in cancer patients: Impact of a low dose CT acquisitions in indeterminate or suspicious solitary focus; TEMP/TDM et scintigraphie osseuse en cancerologie: impact d'une acquisition scannographique basse dose chez les patients avec foyer isole suspect ou de nature indeterminee

    Energy Technology Data Exchange (ETDEWEB)

    Franson, T.; Bardet, S.; Switsers, O.; Aide, N. [CRLCC Francois-Baclesse, 14 - Caen (France); CHU Lyon-Sud, Pierre-Benite, Service de Medecine Nucleaire, 69 - Lyon (France); Loiseau, C. [CRLCC Francois-Baclesse, Unite de Biophysique, 14 - Caen (France); Allouache, D.; Gunzer, K. [CRLCC Francois-Baclesse, Oncologie Medicale, 14 - Caen (France); Allouache, N. [CRLCC Francois-Baclesse, Radiotherapie, 14 - Caen (France)

    2008-05-15

    Aim: To evaluate the usefulness of a low dose SPECT/CT and the added value of an additional 'diagnostic' centred CT-scan in cancer patients with a solitary focus observed on planar whole-body bone scintigraphy (P.W.B.S.) and classified as indeterminate or suspicious. Material and methods Sixty consecutive patients underwent a low dose SPECT/CT acquisition (120 kV, 30 m As, 3 mm slice thickness) followed by a 'diagnostic' CT-scan (120 kV, 100 m As, 1.25 mm slice thickness) centred on the focus. The first observer considered prospectively W.B.S., low-dose SPECT/CT and finally the centred SPECT/CT. A blinded review was performed by a second observer. Results P.W.B.S. depicted solitary indeterminate or suspicious foci in 38 and 22 patients, respectively. SPECT/CT acquisitions clarified 73% (44/60) of the foci. Additional diagnostic CT-scan altered low-dose SPECT/CT results in nine patients. Additional foci (not found by P.W.B.S.) located outside the scanning area of the centred diagnostic CT-scan were found in 20 patients. Inter observer agreement for P.W.B.S., low-dose SPECT/CT and diagnostic SPECT/CT was equal to 0.542, 0.68 and 0.694, respectively. R.O.C. analysis showed no difference between low-dose SPECT/CT and diagnostic SPECT/CT for observer 1 and observer 2. Conclusion This study shows that a conventional low-dose SPECT/CT in patients presenting with a solitary focus on P.W.B.S. is sufficient to improve both accuracy and inter observer variability of bone scanning. A CT volume session should not be limited to the area of the solitary focus since additional foci located outside the centred CT-scan frequently occurred. (authors)

  8. Lung cancer incidence and mortality in National Lung Screening Trial participants who underwent low-dose CT prevalence screening: a retrospective cohort analysis of a randomised, multicentre, diagnostic screening trial

    Science.gov (United States)

    Patz, Edward F; Greco, Erin; Gatsonis, Constantine; Pinsky, Paul; Kramer, Barnett S; Aberle, Denise R

    2016-01-01

    Summary Background Annual low-dose CT screening for lung cancer has been recommended for high-risk individuals, but the necessity of yearly low-dose CT in all eligible individuals is uncertain. This study examined rates of lung cancer in National Lung Screening Trial (NLST) participants who had a negative prevalence (initial) low-dose CT screen to explore whether less frequent screening could be justified in some lower-risk subpopulations. Methods We did a retrospective cohort analysis of data from the NLST, a randomised, multicentre screening trial comparing three annual low-dose CT assessments with three annual chest radiographs for the early detection of lung cancer in high-risk, eligible individuals (aged 55–74 years with at least a 30 pack-year history of cigarette smoking, and, if a former smoker, had quit within the past 15 years), recruited from US medical centres between Aug 5, 2002, and April 26, 2004. Participants were followed up for up to 5 years after their last annual screen. For the purposes of this analysis, our cohort consisted of all NLST participants who had received a low-dose CT prevalence (T0) screen. We determined the frequency, stage, histology, study year of diagnosis, and incidence of lung cancer, as well as overall and lung cancer-specific mortality, and whether lung cancers were detected as a result of screening or within 1 year of a negative screen. We also estimated the effect on mortality if the first annual (T1) screen in participants with a negative T0 screen had not been done. The NLST is registered with ClinicalTrials.gov, number NCT00047385. Findings Our cohort consisted of 26 231 participants assigned to the low-dose CT screening group who had undergone their T0 screen. The 19 066 participants with a negative T0 screen had a lower incidence of lung cancer than did all 26 231 T0-screened participants (371·88 [95% CI 337·97–408·26] per 100 000 person-years vs 661·23 [622·07–702·21]) and had lower lung cancer

  9. The bibliometric analysis of literatures on low -dose CT in CNKI.%基于 CNKI 的国内 CT 低剂量研究文献计量学分析

    Institute of Scientific and Technical Information of China (English)

    王倩; 綦维维; 夏光辉; 赵心明; 马霄虹; 周纯武; 洪楠

    2013-01-01

    Objective The purposes of this study were to evaluate the characteristics and rule of the development in natioanl low -dose CT examination, and to supply a useful reference for future studies. Materials and Methods The journal articles in CNKI which were included by China Academic Journal Network Publishing Database (CAJD) from 2002 to 2011 were processed with Thomson Data Analyzer (TDA). Seven aspects were analyzed: time, authors, funds for scientific research,areal distribution,institutions, authors, and keywords. Results A total 3148 journal articles on low -dose CT examination and 7352 authors were found. The cooperative rate and degree were 63.48% and 2.34, respectively. The famous authors were those who published more than 3 articles. Authors were from 33 areas, 471 institutions of 8 systems. Beijing and Shanghai were the most productive areas, publishing 45.9% articles. There were 10 core journals in this research area. 868 articles were funded by certain grants, and number of articles was increased yearly, indicative of the importance of grant in promoting research. Conclusion The national low-dose CT research was in the young stage compared to the international research, and the research were not evenly distributed national wide. Though the researches have involved multi-institute, multi-system, multi -discipline, the quantities and qualities of papers still have improvement space. Strengthening basic research, improving medical ethics, and optimalizing clinical research methods would promote development of low-dose CT studies.%  目的探讨近十年国内 CT 低剂量领域的研究现状,揭示该领域的发展特点和一般规律,为该领域的进一步深入研究提供参考.方法以中国知网(CNKI)为搜索引擎,中国学术期刊网络出版总库(CAJD)为数据源,检索2002—2011年 CT 低剂量文献,采用 Thomson Data Analyzer(TDA)分析软件进行数据清洗.从年代、发文作者、地区、机构、基金等多方面进

  10. 胸部DR与低剂量螺旋CT扫描在肺癌筛选中的应用观察%Application and Observation of Thoracic DR and Low Dose Spiral CT Scanning in Lung Cancer Screening

    Institute of Scientific and Technical Information of China (English)

    成洪桥

    2014-01-01

    目的:探讨分析胸部DR与低剂量螺旋CT扫描在肺癌筛选中的应用价值。方法选择来我院进行肺癌治疗的300例患者,对他们分别采用胸部DR以及低剂量螺旋CT扫描,统计两种方法的检出率。结果胸部DR检出结节性病变患者24例,占8%,其中肺癌患者3例;低剂量螺旋CT扫描检出结节性病变患者51例,占17%,其中肺癌患者6例,差异具有统计学意义(P<0.05)。结论采用低剂量螺旋CT扫描在肺癌筛选中的应用价值显著,能明显提高检出率。%Objective To investigate the application value of chest DR and low dose spiral CT scanning in lung cancer screening. Methods 300 patients came to our hospital for treatment of lung cancer, they were used on the chest DR and low dose spiral CT scanning, using statistical method for detection rate. Results Chest DR were detected in 24 cases, patients with nodular lesions accounted for 8%, of which 3 cases of lung cancer patients;low dose spiral CT scanning were detected in 51 cases, patients with nodular lesions accounted for 17%, of which 6 cases of lung cancer patients, with significant difference (P<0.05). Conclusion Using low dose spiral CT scanning in lung cancer screening has significant value, it can significantly improve the detection rate.

  11. Emphysema quantification on low-dose CT using percentage of low-attenuation volume and size distribution of low-attenuation lung regions: Effects of adaptive iterative dose reduction using 3D processing

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Mizuho, E-mail: nmizuho@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Matsumoto, Sumiaki, E-mail: sumatsu@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Seki, Shinichiro, E-mail: sshin@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Koyama, Hisanobu, E-mail: hkoyama@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Ohno, Yoshiharu, E-mail: yosirad@kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Fujisawa, Yasuko, E-mail: yasuko1.fujisawa@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); Sugihara, Naoki, E-mail: naoki.sugihara@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); and others

    2014-12-15

    Highlights: • Emphysema quantification (LAV% and D) was affected by image noise on low-dose CT. • For LAV% and D, AIDR 3D improved agreement of quantification on low-dose CT. • AIDR 3D has the potential to quantify emphysema accurately on low-dose CT. - Abstract: Purpose: To evaluate the effects of adaptive iterative dose reduction using 3D processing (AIDR 3D) for quantification of two measures of emphysema: percentage of low-attenuation volume (LAV%) and size distribution of low-attenuation lung regions. Method and materials: : Fifty-two patients who underwent standard-dose (SDCT) and low-dose CT (LDCT) were included. SDCT without AIDR 3D, LDCT without AIDR 3D, and LDCT with AIDR 3D were used for emphysema quantification. First, LAV% was computed at 10 thresholds from −990 to −900 HU. Next, at the same thresholds, linear regression on a log–log plot was used to compute the power law exponent (D) for the cumulative frequency-size distribution of low-attenuation lung regions. Bland–Altman analysis was used to assess whether AIDR 3D improved agreement between LDCT and SDCT for emphysema quantification of LAV% and D. Results: The mean relative differences in LAV% between LDCT without AIDR 3D and SDCT were 3.73%–88.18% and between LDCT with AIDR 3D and SDCT were −6.61% to 0.406%. The mean relative differences in D between LDCT without AIDR 3D and SDCT were 8.22%–19.11% and between LDCT with AIDR 3D and SDCT were 1.82%–4.79%. AIDR 3D improved agreement between LDCT and SDCT at thresholds from −930 to −990 HU for LAV% and at all thresholds for D. Conclusion: AIDR 3D improved the consistency between LDCT and SDCT for emphysema quantification of LAV% and D.

  12. MLEM LOW-DOSE CT RECONSTRUCTION ALGORITHM BASED ON ROAD AND WAVELET SHRINKAGE%基于 ROAD 和小波收缩的 MLEM 低剂量 CT 重建算法

    Institute of Scientific and Technical Information of China (English)

    董婵婵; 桂志国; 张权; 郝慧艳; 张芳; 刘祎; 孙未雅

    2016-01-01

    针对低剂量 CT (Computed Tomography)重建图像质量退化的问题,提出一种基于小波收缩和绝对差值排序各项异性扩散的 MLEM(Maximum Likelihood Expectation Maximization)低剂量 CT 重建算法。算法在每次迭代中首先采用 MLEM算法对低剂量CT 投影数据进行重建。由于各项异性扩散对噪声敏感,所以算法先对重建后的图像进行小波变换,再在更稳定的低频小波域进行基于绝对差值排序的各项异性扩散处理,对小波高频系数进行软阈值降噪处理。然后将降噪处理后的系数进行小波反变换,得到降噪后的图像。最后使用中值滤波对图像进行处理,从而消除脉冲噪声点。实验结果表明,与其他几种常用重建算法相比,该算法重建的图像信噪比更高,归一化均方误差更小,处理后的图像更清晰,即可以在抑制噪声的同时,较好地保持图像的边缘和细节信息。%Concerning the problem of quality degradation of low-dose CT reconstruction images,we presented an MLEM low-dose CT reconstruction method which is based on wavelet shrinkage and rank-ordered absolute differences anisotropic diffusion.In each time of iteration,the algorithm first uses MLEMto reconstruct the low-dose projection data.Since the anisotropic diffusion is sensitive to noises,so the algorithm performs wavelet transform on the reconstructed image prior to conducting anisotropic diffusion processing based on rank-ordered absolute differences in more stable low-frequency wavelet domain and then carries out the soft threshold denoising processing on high-frequency coefficient of wavelet.After that the algorithm performs inverse discrete wavelet transform (IDWT)on the coefficients with denoising treatment and obtains the denoised images.Finally it uses median filter to process the image so as to eliminate the impulse noise points.Experimental results showed that compared with some other common

  13. Reliability analysis of visual ranking of coronary artery calcification on low-dose CT of the thorax for lung cancer screening: comparison with ECG-gated calcium scoring CT.

    Science.gov (United States)

    Kim, Yoon Kyung; Sung, Yon Mi; Cho, So Hyun; Park, Young Nam; Choi, Hye-Young

    2014-12-01

    Coronary artery calcification (CAC) is frequently detected on low-dose CT (LDCT) of the thorax. Concurrent assessment of CAC and lung cancer screening using LDCT is beneficial in terms of cost and radiation dose reduction. The aim of our study was to evaluate the reliability of visual ranking of positive CAC on LDCT compared to Agatston score (AS) on electrocardiogram (ECG)-gated calcium scoring CT. We studied 576 patients who were consecutively registered for health screening and undergoing both LDCT and ECG-gated calcium scoring CT. We excluded subjects with an AS of zero. The final study cohort included 117 patients with CAC (97 men; mean age, 53.4 ± 8.5). AS was used as the gold standard (mean score 166.0; range 0.4-3,719.3). Two board-certified radiologists and two radiology residents participated in an observer performance study. Visual ranking of CAC was performed according to four categories (1-10, 11-100, 101-400, and 401 or higher) for coronary artery disease risk stratification. Weighted kappa statistics were used to measure the degree of reliability on visual ranking of CAC on LDCT. The degree of reliability on visual ranking of CAC on LDCT compared to ECG-gated calcium scoring CT was excellent for board-certified radiologists and good for radiology residents. A high degree of association was observed with 71.6% of visual rankings in the same category as the Agatston category and 98.9% varying by no more than one category. Visual ranking of positive CAC on LDCT is reliable for predicting AS rank categorization.

  14. Postoperative findings following the Whipple procedure : determination of prevalence and morphologic abdominal CT features

    NARCIS (Netherlands)

    Mortele, KJ; Lemmerling, M; de Hemptinne, B; De Vos, M; De Bock, G; Kunnen, M

    2000-01-01

    This study was conducted to determine characteristic CT findings following the Whipple procedure and to evaluate the usefulness of CT in re-dieting tumor recurrence. Eighty-four postoperative abdominal CT scans and medical records of 43 patients were retrospectively reviewed. Perioperative histopath

  15. Quantifying the usefulness of CT in evaluating seniors with abdominal pain

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Lawrence M. [Campus Box 8072, Division of Emergency Medicine, School of Medicine, Washington University, St. Louis, MO 63110 (United States)]. E-mail: lewisl@msnotes.wustl.edu; Klippel, Allen P. [Campus Box 8072, Division of Emergency Medicine, School of Medicine, Washington University, St. Louis, MO 63110 (United States); Bavolek, Rebecca A. [Campus Box 8072, Division of Emergency Medicine, School of Medicine, Washington University, St. Louis, MO 63110 (United States); Ross, Laura M. [Washington University, School of Arts and Science (United States); Scherer, Tara M. [Washington University, School of Arts and Science (United States); Banet, Gerald A. [Campus Box 8072, Division of Emergency Medicine, School of Medicine, Washington University, St. Louis, MO 63110 (United States)

    2007-02-15

    Objectives: (1) Determine if older patients with abdominal pain who receive emergency department (ED) abdominal CT have changes in diagnosis and/or disposition more often than similar patients without CT; (2) compare physician confidence in diagnosis and disposition for patients with versus without CT; (3) document factors that most influence physician's decision to order abdominal CT in this population. Methods: ED patients 60 years of age or older, with acute non-traumatic abdominal pain were enrolled over a 6-week period. Physicians documented a preliminary and final ED diagnosis and disposition, along with pre- and post-evaluation confidence levels. Decision to order CT, along with clinical information most influencing that decision, was noted. Physician confidence levels and percent change in diagnosis and disposition were compared for patients with versus without CT. Results: One hundred and twenty-six patients comprised study sample. Abdominal CT rate was 59% (95%CI, 50-67%). CT was associated with an increased change in diagnosis (46%; 95%CI, 4-58% versus 29%; 95%CI, 16-42%), but no change in disposition between patients with versus without CT. Preliminary diagnostic confidence was lower for EPs who ordered a CT than for those who did not (p < 0.001). Patient history most influenced ordering CT, whereas prior lab/imaging results most influenced not ordering CT. Conclusion: Patients with CT had a change in diagnosis more often than those without. Preliminary diagnostic confidence was lower in CT group. Percent change in disposition did not differ between groups. Physicians most often ordered CT based on history and did not order CT when other diagnostic evaluation supported a specific diagnosis.

  16. An Effort to Develop an Algorithm to Target Abdominal CT Scans for Patients After Gastric Bypass.

    Science.gov (United States)

    Pernar, Luise I M; Lockridge, Ryan; McCormack, Colleen; Chen, Judy; Shikora, Scott A; Spector, David; Tavakkoli, Ali; Vernon, Ashley H; Robinson, Malcolm K

    2016-10-01

    Abdominal CT (abdCT) scans are frequently ordered for Roux-en-Y gastric bypass (RYGB) patients presenting to the emergency department (ED) with abdominal pain, but often do not reveal intra-abdominal pathology. We aimed to develop an algorithm for rational ordering of abdCTs. We retrospectively reviewed our institution's RYGB patients presenting acutely with abdominal pain, documenting clinical and laboratory data, and scan results. Associations of clinical parameters to abdCT results were examined for outcome predictors. Of 1643 RYGB patients who had surgery between 2005 and 2015, 355 underwent 387 abdCT scans. Based on abdCT, 48 (12 %) patients required surgery and 86 (22 %) another intervention. No clinical or laboratory parameter predicted imaging results. Imaging decisions for RYGB patients do not appear to be amenable to a simple algorithm, and patient work-up should be based on astute clinical judgment.

  17. The application value of 64 layers CT low-dose scanning technology in the chest check%64层螺旋 CT低剂量扫描技术在胸部检查中的应用价值

    Institute of Scientific and Technical Information of China (English)

    陈绵荣; 陈志远; 吴辉

    2016-01-01

    Objective Through this research we aimed to explore the application value of 64 layers CT low-dose scanning technology in the chest check.Methods Totally 84 cases of people, who received chest examination by 64 layers CT for medical examination in our hospital during July 2014 and July 2016, were selected as the research objects, according to random number table method all selected objects were divided into low dose group, forty cases in each group.The people in low dose group received low dose 64 layers CT scan, those in routine dose group adopted regular doses of 64 layer CT scan, comparing the diagnosed rate of chest lesions of the two dose groups.Results The diagnosis rate of low dose group was 92.00%, and it was 92.50%of the conventional dose group, the difference between the two groups has no statistical significance (P>0.05). Image quality of both low dose group and conventional dose group are excellent, air-filled bronchi, pleural adhesion, spicule sign, sign of lobulation, nodular density cavity, uneven and calcification can clear display in both groups.Conclusions Diagnose rate of routine dose 64 spiral CT scans was equal to that of low dose 64 spiral CT scans.Compared to conventional treatment, low dose scan can reduce the radiation hazards, reduce the loss of the ball tube, has important application value in clinical.%目的:通过本研究探讨64层螺旋CT低剂量扫描技术在胸部检查中的应用价值。方法选取2013年7月至2016年7月期间在本院行胸部64层螺旋CT检查的80例体检者作为研究对象,按照随机法将所有入选对象分为低剂量组与常规剂量组(各40例),低剂量组行低剂量64层螺旋CT扫描,常规剂量组行常规剂量64层螺旋CT扫描,比较两种剂量对胸部病变的诊出率。结果两组分别经低剂量和常规剂量64层螺旋CT扫描诊断后,低剂量组诊出率为92.00%,常规剂量组诊出率为92.50%,两组间诊出率比

  18. Low-dose rhBMP2/7 heterodimer to reconstruct peri-implant bone defects: a micro-CT evaluation

    NARCIS (Netherlands)

    Wang, J.; Zheng, Y.; Zhao, J.; Liu, T.; Gao, L.; Gu, Z.; Wu, G.

    2012-01-01

    Objectives To delineate the dynamic micro-architectures of bone induced by low-dose bone morphogenetic protein (BMP)-2/7 heterodimer in peri-implant bone defects compared to BMP2 and BMP7 homodimer. Material and Methods Peri-implant bone defects (8 mm in diameter, 4 mm in depth) were created surroun

  19. Low-dose prospectively electrocardiogram-gated axial dual-source CT angiography in patients with pulsatile bilateral bidirectional Glenn Shunt: an alternative noninvasive method for postoperative morphological estimation.

    Directory of Open Access Journals (Sweden)

    Xiaopeng Ji

    Full Text Available OBJECTIVE: To explore the clinical value of low-dose prospectively electrocardiogram-gated axial dual-source CT angiography (low-dose PGA scanning, CTA in patients with pulsatile bilateral bidirectional Glenn shunt (bBDG as an alternative noninvasive method for postoperative morphological estimation. METHODS: Twenty patients with pulsatile bBDG (mean age 4.2±1.6 years underwent both low-dose PGA scanning and conventional cardiac angiography (CCA for the morphological changes. The morphological evaluation included the anatomy of superior vena cava (SVC and pulmonary artery (PA, the anastomotic location, thrombosis, aorto-pulmonary collateral circulation, pulmonary arteriovenous malformations, etc. Objective and subjective image quality was assessed. Bland-Altman analysis and linear regression analyses were used to evaluate the correlation on measurements between CTA and CCA. Effective radiation dose of both modalities was calculated. RESULTS: The CT attenuation value of bilateral SVC and PA was higher than 300 HU. The average subjective image quality score was 4.05±0.69. The morphology of bilateral SVC and PA was displayed completely and intuitively by CTA images. There were 24 SVC above PA and 15 SVC beside PA. Thrombosis was found in 1 patient. Collateral vessels were detected in 13 patients. No pulmonary arteriovenous malformation was found in our study. A strong correlation (R2>0.8, P0.The mean effective dose of CTA and CCA was 0.50±0.17 mSv and 4.85±1.34 mSv respectively. CONCLUSION: CT angiography with a low-dose PGA scanning is an accurate and reliable noninvasive examination in the assessment of morphological changes in patients with pulsatile bBDG.

  20. Low-dose computed tomography to detect body-packing in an animal model

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, M.H., E-mail: martin.maurer@charite.de [Klinik fuer Strahlenheilkunde, Charite - Universitaetsmedizin, Berlin (Germany); Niehues, S.M.; Schnapauff, D.; Grieser, C.; Rothe, J.H. [Klinik fuer Strahlenheilkunde, Charite - Universitaetsmedizin, Berlin (Germany); Waldmueller, D. [Bildungs- und Wissenschaftszentrum der Bundesfinanzverwaltung, Berlin (Germany); Chopra, S.S. [Klinik fuer Allgemein-, Viszeral- und Transplantationschirurgie, Charite - Universitaetsmedizin, Berlin (Germany); Hamm, B.; Denecke, T. [Klinik fuer Strahlenheilkunde, Charite - Universitaetsmedizin, Berlin (Germany)

    2011-05-15

    Objective: To assess the possible extent of dose reduction for low-dose computed tomography (CT) in the detection of body-packing (ingested drug packets) as an alternative to plain radiographs in an animal model. Materials and methods: Twelve packets containing cocaine (purity >80%) were introduced into the intestine of an experimental animal (crossbred pig), which was then repeatedly examined by abdominal CT with stepwise dose reduction (tube voltage, 80 kV; tube current, 10-350 mA). Three blinded readers independently evaluated the CT datasets starting with the lowest tube current and noted the numbers of packets detected at the different tube currents used. In addition, 1 experienced reader determined the number of packets detectable on plain abdominal radiographs and ultrasound. Results: The threshold for correct identification of all 12 drug packets was 100 mA for reader 1 and 125 mA for readers 2 and 3. Above these thresholds all 3 readers consistently identified all 12 packets. The effective dose of a low-dose CT scan with 125 mA (including scout view) was 1.0 mSv, which was below that of 2 conventional abdominal radiographs (1.2 mSv). The reader interpreting the conventional radiographs identified a total of 9 drug packets and detected 8 packets by abdominal ultrasound. Conclusions: Extensive dose reduction makes low-dose CT a valuable alternative imaging modality for the examination of suspected body-packers and might replace conventional abdominal radiographs as the first-line imaging modality.

  1. 低剂量对比剂头颈部CT血管成像%Feasibility of head and neck CT angiography with low dose contrast medium

    Institute of Scientific and Technical Information of China (English)

    周如康; 沈永菊; 刘勇; 冷永新; 邱裕友; 张晓

    2013-01-01

    目的 探讨低剂量对比剂头颈部CTA成像的可行性.方法 根据对比剂剂量和流率,将67例接受头颈部CTA的患者对比剂均为碘帕醇(370 mgI/ml)]随机分为2组:常规组(n=33)以固定流率(4 ml/s)注入90 ml对比剂和20ml生理盐水,个体化组(n=34)根据公式计算所需对比剂剂量和流率[对比剂剂量(ml)=体质量(kg)×λ(ml/kg);流率(ml/s)=对比剂剂量/(曝光时间+7);生理盐水剂量(ml)=(27.5-7-曝光时间)×流率.患者体质量为45~60 kg时,λ=0.8 ml/kg;61~75 kg时λ=0.9 ml/kg;>75 kg时λ=1.0 ml/kg].测量主动脉弓、双侧颈总动脉分又和双侧大脑中动脉起始段相应层面的增强CT值.采用单因素方差分析比较CT值和对比剂剂量,以t检验比较两组大脑中动脉图像质量.结果 常规组和个体化组主动脉弓CT值分别为(414.20±6.24)HU、(435.36±6.44) HU(P<0.001);右颈总动脉分叉处CT值分别为(434.29±6.25)HU、(459.85±6.48) HU(P<0.001);左颈总动脉分叉处CT值分别为(435.42±6.26)HU、(458.43±6.42) HU(P<0.001).常规组和个体化组右大脑中动脉起始段CT值分别为(291.03±10.08) HU、(267.55±9.88)HU(P=0.180);左大脑中动脉起始段CT值分别为(289.94±9.80) HU、(269.50±9.86) HU(P=0.169).常规组每例对比剂剂量均为90 ml,个体化组平均剂量为(59.41±7.91) ml(F=508.474,P<0.001).常规组大脑中动脉图像质量等级优秀、良好和一般分别为28、4和1例,个体化组分别为27、6和1例(P=0.874).结论 通过个体化解决方案,降低头颈部CTA成像的对比剂剂量是切实可行的.%Objective To observe the feasibility of head and neck CTA with low dose contrast medium.Methods Sixty-seven patients who underwent head and neck CTA were randomly divided into 2 groups according to different contrast medium dosage and flow rate.MSCTA was performed using iopamidol (370 mgI/ml).In the routine group (n=33),an option of regular flow rate (4 ml/s) and injection volume (90

  2. 基于投影数据非单调性全变分恢复的低剂量CT重建%Nonmonotone Total Variation Minimization Based Projection Restoration for Low-Dose CT Reconstruction

    Institute of Scientific and Technical Information of China (English)

    钱姗姗; 黄静; 马建华; 张华; 刘楠; 张喜乐; 冯前进; 陈武凡

    2011-01-01

    为获取低剂量CT图像的优质重建,本文提出一种基于投影数据非单调性全变分恢复的低剂量CT重建方法.新方法首先通过非线性Anscombe变换将满足Poisson分布的投影数据转化为近似Gaussian分布,其后对变换后的Gaussian型数据进行非单调性全变分最小化算法(Nonmonotone Total Variation Minimization,NTVM)滤波,最后对Anscombe逆变换数据实现传统的滤波反投影(Filtered Back Projection,FBP) CT重建.仿真和临床低剂量CT重建实验表明,本文方法在噪声清除、伪影抑制和缩短重建时间等方面均有上佳表现.%In order to improve the reconstruction quality of low-dose CT image,a new approach is proposed based on low-dose CT projection restoration in this paper. First, projection data is transformed from Poisson distribution to Gaussian distribution using nonlinear Anscombe transform. Then, the Anscombe transformed data is filtered by an efficient nonmonotone total variation minimization denoising algorithm. Last, the reconstruction is achieved by inverse Anscombe transform and filtered back projection (FBP) method. Simulated and clinical low-dose CT data experimental results demonstrate that a high-quality CT image can be reconstructed.

  3. A study of Iterative reconstruction algorithm in low dose CT perfusion of brain%低剂量脑 CT 灌注的迭代重建研究

    Institute of Scientific and Technical Information of China (English)

    黎佩君; 黄飚; 梁长虹; 朱文珍; 龙晚生

    2015-01-01

    Objective:To assess the image quality of low dose CT perfusion (CTP)of brain with iterative reconstruc-tion algorithm.Methods:43 patients with suspected cerebrovascular ischemic disorders were enrolled in the study.All pa-tients underwent CTP of brain.Datasets of CTP were reconstructed by using IR and FBP algorithms.The objective image quality of CTP source image and the subjective quality of color coded perfusion maps of the two sets were assessed and com-pared.Results:Comparing the imaging scores of the four perfusion maps (CBV、CBF、MTT、TTP)after IR and FBP recon-struction,the P values of differentiating gray/white matter with these two algorithms were 0.317,0.157,0.257,0.083 re-spectively;the P values of scoring artifacts severity of images were 0.083,0.046;<0.001,0.011 respectively.The brain CTP reconstructed by using IR was superior to those reconstructed by FBP in following aspects:objective image quality,im-aging scores and total image quality.Significant statistical differences were showed in all above aspects (P <0.05).Conclu-sion:Employing IR algorithm to reconstruct low dose CT perfusion of brain,not only can improve the image quality,but also reduce radiation dose.Additionally,high diagnostic effectiveness could be obained.%目的:探讨迭代重建(IR)技术对低剂量脑 CT 灌注(CTP)图像质量的影响。方法:43例缺血性脑血管病患者行低剂量脑 CTP,CTP 原始图像分别经 IR 和滤波反投影(FBP)重建得到两组图像,比较两组图像客观质量及灌注参数图的主观质量。结果:对经 IR 及 FBP 重建的灌注参数图(CBV、CBF、MTT、TTP)进行评分并比较,两组各灌注参数图脑灰白质分界评分 P 值分别为0.317、0.157、0.257、0.083,图像伪影严重程度评分 P 值分别为0.083、0.046、<0.001、0.011。经 IR 重建的 CTP 原始图像客观质量及灌注参数图的图像均匀性、总体图像质量均优于 FBP 重建,且差

  4. Respiratory motion reduction in PET/CT using abdominal compression for lung cancer patients.

    Directory of Open Access Journals (Sweden)

    Tzung-Chi Huang

    Full Text Available PURPOSE: Respiratory motion causes substantial artifacts in reconstructed PET images when using helical CT as the attenuation map in PET/CT imaging. In this study, we aimed to reduce the respiratory artifacts in PET/CT images of patients with lung tumors using an abdominal compression device. METHODS: Twelve patients with lung cancer located in the middle or lower lobe of the lung were recruited. The patients were injected with 370 MBq of 18F-FDG. During PET, the patients assumed two bed positions for 1.5 min/bed. After conducting free-breathing imaging, we obtained images of the patients with abdominal compression by applying the same setup used in the free-breathing scan. The differences in the standardized uptake value (SUVmax, SUVmean, tumor volume, and the centroid of the tumors between PET and various CT schemes were measured. RESULTS: The SUVmax and SUVmean derived from PET/CT imaging using an abdominal compression device increased for all the lesions, compared with those obtained using the conventional approach. The percentage increases were 18.1% ±14% and 17% ±16.8% for SUVmax and SUVmean, respectively. PET/CT imaging combined with abdominal compression generally reduced the tumor mismatch between CT and the corresponding attenuation corrected PET images, with an average decrease of 1.9±1.7 mm over all the cases. CONCLUSIONS: PET/CT imaging combined with abdominal compression reduces respiratory artifacts and PET/CT misregistration, and enhances quantitative SUV in tumor. Abdominal compression is easy to set up and is an effective method used in PET/CT imaging for clinical oncology, especially in the thoracic region.

  5. 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.)

  6. CT in the diagnosis of abdominal wall hernias: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Hoejer, A.M.; Jess, P. [Department of Surgery, Roskilde County Hospital Koege, DK-4600 Koege (Denmark); Rygaard, H. [Department of Radiology, Roskilde County Hospital Koege, DK-4600 Koege (Denmark)

    1997-12-01

    The aim of the study was to estimate the value of CT in the diagnosis of abdominal wall hernias and at the same time to create a standard for this CT investigation. Twenty-four patients with suspected hernia of the abdominal wall were examined. All were operated on. The CT scans were assessed by two radiologists to estimate the interobserver variation. The CT diagnoses made by the two radiologists were correct in 83 % and 79 % of cases, respectively. The sensitivity was 0.83 in both CT evaluations and the specificity was 0.83 and 0.67, respectively. The predictive value of a positive CT finding was 0.94 and 0.88, while the predictive value of a negative CT finding was 0.63 and 0.57, respectively. The interobserver variation (kappa) was 0.87. The study therefore indicates that a positive CT finding of abdominal wall hernia is reliable, while a negative finding does not exclude the diagnosis. The interobserver variation of the CT diagnoses is acceptable. To achieve the highest diagnostic accuracy, it is recommended to always use the Valsalva manoeuvre, oral intake of contrast and 10/10 mm CT slices. (orig.) With 3 figs., 1 tab., 7 refs.

  7. Cholestrol granuloma of the breast incidentally detected on dynamic abdominal CT: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Sun Hye; Lee, Eun Hye; Hong, Hyun Sook; Kwak, Jeong Ja [Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon (Korea, Republic of)

    2016-01-15

    A breast cholesterol granuloma is an uncommon nodular breast lesion. We incidentally detected a persistently enhancing breast mass on the dynamic abdominal computed tomography (CT) of a 78-year-old woman. The mass decreased in diameter over 50 days following a core needle biopsy. This report is the first to describe the dynamic-enhanced CT features of a breast cholesterol granuloma.

  8. Abdominal manifestations of polyarteritis nodosa demonstrated with CT

    Energy Technology Data Exchange (ETDEWEB)

    Adaletli, Ibrahim; Ozpeynirci, Yigit; Kurugoglu, Sebuh [Istanbul University, Department of Radiology, Cerrahpasa Medical School, Istanbul (Turkey); Sever, Lale; Arisoy, Nil [Istanbul University, Department of Pediatric Nephrology, Istanbul (Turkey)

    2010-05-15

    We report a rare case of polyarteritis nodosa (PAN) presenting in childhood. The child had multiple visceral aneurysms and later developed ascending colitis and jejunitis. The diagnosis was established with multidetector CT and CT angiography. (orig.)

  9. Intra-abdominal desmoplastic small round-cell tumour: multiphase CT findings in two children

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hyoung; Goo, Hyun Woo; Yoon, Chong Hyun [Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-2 dong, Songpa-gu, Seoul, 138-736 (Korea)

    2003-06-01

    We report the multiphase CT findings of intra-abdominal desmoplastic small round-cell tumour (DSRCT) in two children. CT showed a huge heterogeneous intraperitoneal mass with or without direct invasion into solid organs such as liver or kidney, extensive intraperitoneal seeding, intratumoural calcification, ascites, and lymphadenopathy. DSRCT should be included in the differential diagnosis of malignant intraperitoneal neoplasm in children. Multiphase CT may be helpful in delineating tumour extent, vascularity and direct invasion into adjacent organs. (orig.)

  10. Deformable registration of abdominal kilovoltage treatment planning CT and tomotherapy daily megavoltage CT for treatment adaptation

    Science.gov (United States)

    Yang, Deshan; Chaudhari, Summer R.; Goddu, S. Murty; Pratt, David; Khullar, Divya; Deasy, Joseph O.; El Naqa, Issam

    2009-01-01

    In adaptive radiation therapy the treatment planning kilovoltage CT (kVCT) images need to be registered with daily CT images. Daily megavoltage CT (MVCT) images are generally noisier than the kVCT images. In addition, in the abdomen, low image contrast, differences in bladder filling, differences in bowel, and rectum filling degrade image usefulness and make deformable image registration very difficult. The authors have developed a procedure to overcome these difficulties for better deformable registration between the abdominal kVCT and MVCT images. The procedure includes multiple image preprocessing steps and a two deformable registration steps. The image preprocessing steps include MVCT noise reduction, bowel gas pockets detection and painting, contrast enhancement, and intensity manipulation for critical organs. The first registration step is carried out in the local region of the critical organs (bladder, prostate, and rectum). It requires structure contours of these critical organs on both kVCT and MVCT to obtain good registration accuracy on these critical organs. The second registration step uses the first step results and registers the entire image with less intensive computational requirement. The two-step approach improves the overall computation speed and works together with these image preprocessing steps to achieve better registration accuracy than a regular single step registration. The authors evaluated the procedure on multiple image datasets from prostate cancer patients and gynecological cancer patients. Compared to rigid alignment, the proposed method improves volume matching by over 60% for the critical organs and reduces the prostate landmark registration errors by 50%. PMID:19291972

  11. Unsupervised quantification of abdominal fat from CT images using Greedy Snakes

    Science.gov (United States)

    Agarwal, Chirag; Dallal, Ahmed H.; Arbabshirani, Mohammad R.; Patel, Aalpen; Moore, Gregory

    2017-02-01

    Adipose tissue has been associated with adverse consequences of obesity. Total adipose tissue (TAT) is divided into subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). Intra-abdominal fat (VAT), located inside the abdominal cavity, is a major factor for the classic obesity related pathologies. Since direct measurement of visceral and subcutaneous fat is not trivial, substitute metrics like waist circumference (WC) and body mass index (BMI) are used in clinical settings to quantify obesity. Abdominal fat can be assessed effectively using CT or MRI, but manual fat segmentation is rather subjective and time-consuming. Hence, an automatic and accurate quantification tool for abdominal fat is needed. The goal of this study is to extract TAT, VAT and SAT fat from abdominal CT in a fully automated unsupervised fashion using energy minimization techniques. We applied a four step framework consisting of 1) initial body contour estimation, 2) approximation of the body contour, 3) estimation of inner abdominal contour using Greedy Snakes algorithm, and 4) voting, to segment the subcutaneous and visceral fat. We validated our algorithm on 952 clinical abdominal CT images (from 476 patients with a very wide BMI range) collected from various radiology departments of Geisinger Health System. To our knowledge, this is the first study of its kind on such a large and diverse clinical dataset. Our algorithm obtained a 3.4% error for VAT segmentation compared to manual segmentation. These personalized and accurate measurements of fat can complement traditional population health driven obesity metrics such as BMI and WC.

  12. SU-C-207-03: Optimization of a Collimator-Based Sparse Sampling Technique for Low-Dose Cone-Beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T; Cho, S [KAIST, Daejon (Korea, Republic of); Kim, I; Han, B [EB Tech Co., Ltd., Daejeon (Korea, Republic of)

    2015-06-15

    Purpose: In computed tomography (CT) imaging, radiation dose delivered to the patient is one of the major concerns. Sparse-view CT takes projections at sparser view angles and provides a viable option to reducing dose. However, a fast power switching of an X-ray tube, which is needed for the sparse-view sampling, can be challenging in many CT systems. We have earlier proposed a many-view under-sampling (MVUS) technique as an alternative to sparse-view CT. In this study, we investigated the effects of collimator parameters on the image quality and aimed to optimize the collimator design. Methods: We used a bench-top circular cone-beam CT system together with a CatPhan600 phantom, and took 1440 projections from a single rotation. The multi-slit collimator made of tungsten was mounted on the X-ray source for beam blocking. For image reconstruction, we used a total-variation minimization (TV) algorithm and modified the backprojection step so that only the measured data through the collimator slits are to be used in the computation. The number of slits and the reciprocation frequency have been varied and the effects of them on the image quality were investigated. We also analyzed the sampling efficiency: the sampling density and data incoherence in each case. We tested three sets of slits with their number of 6, 12 and 18, each at reciprocation frequencies of 10, 30, 50 and 70 Hz/ro. Results: Consistent results in the image quality have been produced with the sampling efficiency, and the optimum condition was found to be using 12 slits at 30 Hz/ro. As image quality indices, we used the CNR and the detectability. Conclusion: We conducted an experiment with a moving multi-slit collimator to realize a sparse-sampled cone-beam CT. Effects of collimator parameters on the image quality have been systematically investigated, and the optimum condition has been reached.

  13. Evaluation of the use of automatic exposure control and automatic tube potential selection in low-dose cerebrospinal fluid shunt head CT

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, Adam N.; Bagade, Swapnil; Chatterjee, Arindam; Hicks, Brandon; McKinstry, Robert C. [Barnes Jewish Hospital, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, St. Louis, MO (United States); Vyhmeister, Ross [Washington University School of Medicine, St. Louis, MO (United States); Ramirez-Giraldo, Juan Carlos [Siemens Healthcare, Malvern, PA (United States)

    2015-03-17

    Cerebrospinal fluid shunts are primarily used for the treatment of hydrocephalus. Shunt complications may necessitate multiple non-contrast head CT scans resulting in potentially high levels of radiation dose starting at an early age. A new head CT protocol using automatic exposure control and automated tube potential selection has been implemented at our institution to reduce radiation exposure. The purpose of this study was to evaluate the reduction in radiation dose achieved by this protocol compared with a protocol with fixed parameters. A retrospective sample of 60 non-contrast head CT scans assessing for cerebrospinal fluid shunt malfunction was identified, 30 of which were performed with each protocol. The radiation doses of the two protocols were compared using the volume CT dose index and dose length product. The diagnostic acceptability and quality of each scan were evaluated by three independent readers. The new protocol lowered the average volume CT dose index from 15.2 to 9.2 mGy representing a 39 % reduction (P < 0.01; 95 % CI 35-44 %) and lowered the dose length product from 259.5 to 151.2 mGy/cm representing a 42 % reduction (P < 0.01; 95 % CI 34-50 %). The new protocol produced diagnostically acceptable scans with comparable image quality to the fixed parameter protocol. A pediatric shunt non-contrast head CT protocol using automatic exposure control and automated tube potential selection reduced patient radiation dose compared with a fixed parameter protocol while producing diagnostic images of comparable quality. (orig.)

  14. Construction of Abdominal Probabilistic Atlases and Their Value in Segmentation of Normal Organs in Abdominal CT Scans

    Science.gov (United States)

    Park, Hyunjin; Hero, Alfred; Bland, Peyton; Kessler, Marc; Seo, Jongbum; Meyer, Charles

    A good abdominal probabilistic atlas can provide important information to guide segmentation and registration applications in the abdomen. Here we build and test probabilistic atlases using 24 abdominal CT scans with available expert manual segmentations. Atlases are built by picking a target and mapping other training scans onto that target and then summing the results into one probabilistic atlas. We improve our previous abdominal atlas by 1) choosing a least biased target as determined by a statistical tool, i.e. multidimensional scaling operating on bending energy, 2) using a better set of control points to model the deformation, and 3) using higher information content CT scans with visible internal liver structures. One atlas is built in the least biased target space and two atlases are built in other target spaces for performance comparisons. The value of an atlas is assessed based on the resulting segmentations; whichever atlas yields the best segmentation performance is considered the better atlas. We consider two segmentation methods of abdominal volumes after registration with the probabilistic atlas: 1) simple segmentation by atlas thresholding and 2) application of a Bayesian maximum a posteriori method. Using jackknifing we measure the atlas-augmented segmentation performance with respect to manual expert segmentation and show that the atlas built in the least biased target space yields better segmentation performance than atlases built in other target spaces.

  15. Long-term follow-up of non-calcified pulmonary nodules (<10 mm) identified during low-dose CT screening for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, Michael M.; Logan, P.M.; Lee, Michael J. [Beaumont Hospital, Department of Radiology, Dublin (Ireland); Foley, Claire; Kenny, Dermot [Beaumont Hospital, Clinical Research Centre, RCSI, Dublin (Ireland); Costello, Richard W. [Beaumont Hospital, Respiratory Division, Dublin (Ireland)

    2012-09-15

    To assess the long-term stability of small (<10 mm) non-calcified pulmonary nodules (NCNs) in high-risk subjects initially screened for lung cancer using low-dose chest computed tomography (LDCCT). A total of 449 subjects initially underwent screening with serial LDCCT over a 2-year period. Participants identified as having NCNs {>=}10 mm were referred for formal lung cancer workup. NCNs <10 mm diameter were followed in accordance with the study protocol. Seven years after baseline screening, subjects with previously documented NCNs <10 mm, which were unchanged in size after the 2-year follow-up period, were re-imaged using LDCCT to assess for interval nodule growth. Eighty-three subjects with previously documented stable NCNs <10 mm underwent LDCCT at 7 years. NCNs were unchanged in 78 subjects and had decreased in size in 4 subjects. There was interval growth of an NCN (from 6 mm to 9 mm) in one subject re-imaged at 7 years, but this nodule has remained stable in size over a further 2-year follow-up period. Non-calcified pulmonary nodules <10 mm in size that are unchanged in size or smaller after 2 years of follow-up with LDCCT are most likely benign. (orig.)

  16. Nutrient intake and nutrient patterns and risk of lung cancer among heavy smokers: results from the COSMOS screening study with annual low-dose CT.

    Science.gov (United States)

    Gnagnarella, Patrizia; Maisonneuve, Patrick; Bellomi, Massimo; Rampinelli, Cristiano; Bertolotti, Raffaella; Spaggiari, Lorenzo; Palli, Domenico; Veronesi, Giulia

    2013-06-01

    The role of nutrients in lung cancer aetiology remains controversial and has never been evaluated in the context of screening. Our aim was to investigate the role of single nutrients and nutrient patterns in the aetiology of lung cancer in heavy smokers. Asymptomatic heavy smokers (≥20 pack-years) were invited to undergo annual low-dose computed tomography. We assessed diet using a self-administered food frequency questionnaire and collected information on multivitamin supplement use. We performed principal component analysis identifying four nutrient patterns and used Cox proportional Hazards regression to assess the association between nutrients and nutrients patterns and lung cancer risk. During a mean follow-up of 5.7 years, 178 of 4,336 participants were diagnosed with lung cancer by screening. We found a significant risk reduction of lung cancer with increasing vegetable fat consumption (HR for highest vs. lowest quartile = 0.50, 95% CI = 0.31-0.80; P-trend = 0.02). Participants classified in the high "vitamins and fiber" pattern score had a significant risk reduction of lung cancer (HR = 0.57; 95% CI = 0.36-0.90, P-trend = 0.01). Among heavy smokers enrolled in a screening trial, high vegetable fat intake and adherence to the "vitamin and fiber" nutrient pattern were associated with reduced lung cancer incidence.

  17. Low-dose adaptive sequential scan for dual-source CT coronary angiography in patients with high heart rate: Comparison with retrospective ECG gating

    Energy Technology Data Exchange (ETDEWEB)

    Xu Lei, E-mail: leixu2001@hotmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Yang Lin, E-mail: anna7949@163.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Zhang Zhaoqi, E-mail: zhaoqi5000@vip.sohu.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Li Yu, E-mail: athen06@hotmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Fan Zhanming, E-mail: fanzm120@tom.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Ma Xiaohai, E-mail: maxi8238@gmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Lv Biao, E-mail: biao_lu2007@sina.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Yu Wei, E-mail: yuwei02@gmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China)

    2010-11-15

    Purpose: To explore feasibility of dual-source CT (DS-CT) prospective ECG-gated coronary angiography in patients with heart rate (HR) higher than 70 beat per minute (bpm), and evaluate image quality and radiation dose with comparison to retrospective ECG-gated spiral scan. Materials and methods: One hundred patients who underwent DS-CT coronary angiography (DS-CTCA) with mean HR higher than 70 bpm but below 110 bpm were enrolled in the study, 50 were scanned by adaptive sequential scan and another 50 were analyzed by retrospectively gated CT scan. The imaging quality of coronary artery segments in the two groups was evaluated using a four-point grading scale by two independent reviewers. Patient radiation dose was calculated by multiplying dose length product by conversion coefficient of 0.017. Results: There was no significant difference between the two groups for mean HR (p = 0.305), HR variability (p = 0.103), body mass index (p = 0.472), and scan length (p = 0.208). There was good agreement for image quality scoring between the two reviewers (Kappa = 0.72). Coronary evaluability of adaptive sequential scan was 99.7% (608 of 610 segments), while that of retrospective gated scan was 98.7% (614 of 622 segments), showing similar coronary evaluability (p = 0.061). Effective doses of adaptive sequential scan and retrospective gated scan were 5.1 {+-} 1.6 and 11.8 {+-} 4.5 mSv, respectively (p < 0.001), showing that adaptive sequential scan reduced radiation dose by 57% compared with that of retrospective gated scan. Conclusions: In patients with 70-110 bpm HR, DS-CTCA adaptive sequential scan shows similar image quality as retrospective ECG-gated spiral scan with 57% reduction of radiation dose.

  18. Comparison of iterative model, hybrid iterative, and filtered back projection reconstruction techniques in low-dose brain CT: impact of thin-slice imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nakaura, Takeshi; Iyama, Yuji; Kidoh, Masafumi; Yokoyama, Koichi [Amakusa Medical Center, Diagnostic Radiology, Amakusa, Kumamoto (Japan); Kumamoto University, Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto (Japan); Oda, Seitaro; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto (Japan); Tokuyasu, Shinichi [Philips Electronics, Kumamoto (Japan); Harada, Kazunori [Amakusa Medical Center, Department of Surgery, Kumamoto (Japan)

    2016-03-15

    The purpose of this study was to evaluate the utility of iterative model reconstruction (IMR) in brain CT especially with thin-slice images. This prospective study received institutional review board approval, and prior informed consent to participate was obtained from all patients. We enrolled 34 patients who underwent brain CT and reconstructed axial images with filtered back projection (FBP), hybrid iterative reconstruction (HIR) and IMR with 1 and 5 mm slice thicknesses. The CT number, image noise, contrast, and contrast noise ratio (CNR) between the thalamus and internal capsule, and the rate of increase of image noise in 1 and 5 mm thickness images between the reconstruction methods, were assessed. Two independent radiologists assessed image contrast, image noise, image sharpness, and overall image quality on a 4-point scale. The CNRs in 1 and 5 mm slice thickness were significantly higher with IMR (1.2 ± 0.6 and 2.2 ± 0.8, respectively) than with FBP (0.4 ± 0.3 and 1.0 ± 0.4, respectively) and HIR (0.5 ± 0.3 and 1.2 ± 0.4, respectively) (p < 0.01). The mean rate of increasing noise from 5 to 1 mm thickness images was significantly lower with IMR (1.7 ± 0.3) than with FBP (2.3 ± 0.3) and HIR (2.3 ± 0.4) (p < 0.01). There were no significant differences in qualitative analysis of unfamiliar image texture between the reconstruction techniques. IMR offers significant noise reduction and higher contrast and CNR in brain CT, especially for thin-slice images, when compared to FBP and HIR. (orig.)

  19. Infected abdominal aortic aneurysm due to Morganella morganii: CT findings.

    Science.gov (United States)

    Kwon, Oh Young; Lee, Jong Seok; Choi, Han Sung; Hong, Hoon Pyo; Ko, Young Gwan

    2011-02-01

    An infected aortic aneurysm, or mycotic aneurysm, is a rare arterial dilatation due to destruction of the infected vessel wall. Common pathogens resulting in an infected aortic aneurysm are Salmonella and Clostridium species, as well as Staphylococcus aureus; Morganella morganii, on the other hand, is very rare. An infected abdominal aortic aneurysm has tendencies to grow rapidly and to rupture. The mortality rate is high in patients undergoing emergent surgical intervention. We report the case of a 65-year-old man who presented with an infected abdominal aortic aneurysm caused by M. morganii. A high index of suspicion and imaging tests are necessary in order to diagnose an infected aortic aneurysm.

  20. Low dose scanning of 64 slice spiral CT in the diagnosis of pneumothorax in neonates%64层螺旋CT低剂量扫描在新生儿气胸诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    武军; 李彦杰

    2015-01-01

    目的:探讨64层螺旋CT低剂量扫描在新生儿气胸诊断中的应用,分析新生儿气胸的CT表现特点,以提高对新生儿气胸的认识及CT的诊断水平。方法用64层螺旋CT对23例临床可疑新生儿气胸进行低电压、低电流和增大螺距进行扫描,并对图像进行分析。结果患儿有不同类型的CT表现,如外侧肺气胸、内侧纵隔旁气胸、膈面附近及胸前部气胸等。结论新生儿肺气胸有一定的临床CT特征,对及时发现新生儿气胸,对临床诊断并及时处理有重要意义。%Objective Application of low dose of 64 row spiral CT scanning in the diagnosis of pneumothorax in neonatal pneumothorax, analysis CT charac-teristics, in order to improve the diagnostic level of understanding and CT on neonatal pneumothorax. Methods Twenty-three patients with clinically suspected of pneumothorax in neonates of low voltage, low current and increasing pitch were scanned by 64 slice spiral CT. And the image analysis. Results Patients with CT showed different types, such as lateral lung chest,medial mediastinum side pneumothorax, diaphrag-matic surface and near the front of pneumothorax. Conclusion Neonatal lung chest clinic and CT features, the timely detection of pneumothorax in neonates, for clinical diagnosis and timely treatment is meaningful.

  1. SU-E-I-39: Combining Conventional Tomographic Imaging Strategy and Interior Tomography for Low Dose Dual-Energy CT (DECT)

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Q [School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Xing, L [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Xiong, G; Elmore, K; Min, J [Dalio Institute of Cardiovascular Imaging, New York- Presbyterian Hospital and Weill Cornell Medical College, New York, NY (United States)

    2015-06-15

    Purpose: Dual-energy CT (DECT) affords quantitative information of tissue density and provides a new dimension for disease diagnosis and treatment planning. The technique, however, increases the imaging dose because of the doubled scans, and thus hinders its widespread clinical applications. The purpose of this work is to develop a novel hybrid DECT image acquisition and reconstruction strategy, in which one of the energies is dealt by interior tomography while the other one is obtained using conventional tomography approach. Methods: In the proposed hybrid imaging strategy, the projection data of one of the energies (e.g., high-energy) were acquired and processed in an interior scanning model, whereas the other energy in the conventional tomographic approach. It known that, if the ROI is piecewise constant or polynomial, the interior ROI can be reconstructed with TV or HOT minimization. Here we extend the TV based interior reconstruction method into dual-energy situation. The ROI images so obtained were overlaid in the context of conventional CT of the companion energy. A material based composition in ROI was used in the proposed reconstruction framework. Results: In the simulation experiment with a diagnostic DECT geometry and energies, we were able to derive the densities of soft-tissues and bones in the ROI with high fidelity. In the experimental CBCT study, both kV and MV data were collected using the on-board kV and MV imaging system. The MV data were truncated only across the ROI. Using the interior tomography reconstruction above, we were able to obtain the ROI images as that obtained using un-truncated MV data with known tissue densities. Conclusion: The proposed DECT imaging strategy provides an effective way to extract tissue density information in the ROI and in the context of anatomical images of CT imaging, with much reduced imaging dose.

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

    Science.gov (United States)

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

    2016-01-01

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

  3. Feasibility of low-dose contrast medium high pitch CT angiography for the combined evaluation of coronary, head and neck arteries.

    Directory of Open Access Journals (Sweden)

    Zhiwei Wang

    Full Text Available PURPOSE: To evaluate the image quality and radiation dose of combined heart, head, and neck CT angiography (CTA using prospectively electrocardiography (ECG-triggered high-pitch spiral scan protocol, compared with single coronary CTA. MATERIALS AND METHODS: 151 consecutive patients were prospectively included and randomly divided into three groups. Group 1 (n = 47 underwent combined heart, neck, and head CTA using prospectively ECG-triggered high-pitch spiral (Flash scan protocol with a single-phase intravenous injection of iodinated contrast and saline flush; Group 2 (n = 51 underwent single coronary CTA with Flash scan protocol; and Group 3 (n = 53 underwent single coronary CTA with prospective sequence scan protocol. All patients were examined on a dual source CT (Definition FLASH. The image quality was determined for each CT study. RESULTS: Patients of scanning protocol Group 1, 2, and 3 showed no significant differences in age, sex, heart rates, and BMI. Evaluation of coronary artery image quality showed comparable results in the three scanning protocol groups on a per patient-based analysis. In group 1, image quality was found to be sufficient to be diagnostic in all arterial segments of carotid arteries. The mean dose-length product (DLP for group 1 was 256.3±24.5 mGy×cm and was significantly higher in comparison with group 2 (93.4±19.9 mGy×cm; p < 0.001. However, there was no significant difference of DLP between group 1 and group 3 (254.1±69.9 mGy×cm. CONCLUSIONS: The combined heart, neck, and head arteries scan using prospectively electrocardiography (ECG-triggered high-pitch spiral scan protocol in 1 single examination resulted in an excellent opacification of the aorta, the carotid arteries, and the coronary arteries and provided a good image quality with low radiation dose.

  4. A comparative study of seed localization and dose calculation on pre- and post-implantation ultrasound and CT images for low-dose-rate prostate brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Imad; Algan, Ozer; Thompson, Spencer; Sindhwani, Puneet; Herman, Terence; Cheng, C.-Y.; Ahmad, Salahuddin [Department of Radiation Oncology, University of Oklahoma Health Sciences Center, 825 NE 10th Street, OUPB 1430, Oklahoma City, OK 73104 (United States)], E-mail: iali@ouhsc.edu

    2009-09-21

    This work investigates variation in the volume of the prostate measured at different stages through the prostate brachytherapy procedure for 30 patients treated with I-125 radioactive seeds. The implanted seeds were localized on post-implantation ultrasound (US) images and the effect of prostate enlargement due to edema on dose coverage for 15 patients was studied. The volume of the prostate was measured at four stages as follows: (a) 2-3 weeks prior to implantation using US imaging, (b) then at the start of the intra-operative prostate brachytherapy procedure on the day of the implant, (c) immediately post-implantation using US imaging in the operating room and (d) finally by CT imaging at nearly 4 weeks post-implantation. Comparative prostate volume studies were performed using US imaging stepper and twister modes. For the purpose of this study, the implanted seeds were localized successfully on post-implant ultrasound twister images, retrospectively. The plans using post-implant US imaging were compared with intra-operative plans on US and plans created on CT images. The prostate volume increases about 10 cm{sup 3} on average due to edema induced by needle insertion and seed loading during implantation. The visibility of the implanted seeds on US twister images acquired post-implantation is as good as those on CT images and can be localized and used for dose calculation. The dose coverage represented by parameters such as D90 (dose covering 90% of the volume) and V100 (volume covered by 100% dose) is poorer on plans performed on post-implantation twister US studies than on the intra-operative live plan or the CT scan performed 4 weeks post-operatively. For example, the mean D90 difference on post-implantation US is lower by more than 15% than that on pre-implantation US. The volume enlargement of the prostate due to edema induced by needle insertion and seed placement has a significant effect on the quality of dosimetric coverage in brachytherapy prostate seed

  5. Evaluation of a Chest Circumference-Adapted Protocol for Low-Dose 128-Slice Coronary CT Angiography with Prospective Electrocardiogram Triggering

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chenying; Wang, Zufei; Ji, Jiansong; Wang, Hailin; Hu, Xianghua; Chen, Chunmiao [Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000 (China)

    2015-11-01

    To assess the effect of chest circumference-adapted scanning protocol on radiation exposure and image quality in patients undergoing prospective electrocardiogram (ECG)-triggered coronary CT angiography (CCTA). One hundred-eighty-five consecutive patients, who had undergone prospective ECG triggering CCTA with a 128-slice CT, were included in the present study. Nipple-level chest circumference, body weight and height were measured before CT examinations. Patients were divided into four groups based on kV/ref·mAs = 100/200, 100/250, 120/200, and 120/250, when patient's chest circumference was ≤ 85.0 (n = 56), 85.0-90.0 (n = 53), 90.0-95.0 (n = 44), and > 95.0 (n = 32), respectively. Image quality per-segment was independently assessed by two experienced observers. Image noise and attenuation were also measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The effective radiation dose was calculated using CT dose volume index and the dose-length product. A significant correlation was observed between patients' chest circumference and body mass index (r = 0.762, p < 0.001). Chest circumference ranged from 74 to 105 cm, and the mean effective radiation dose was 1.9-3.8 mSv. Diagnostic image quality was obtained in 98.5% (2440/2478) of all evaluated coronary segments without any significant differences among the four groups (p = 0.650). No significant difference in image noise was observed among the four groups (p = 0.439), thus supporting the validity of the chest circumference-adapted scanning protocol. However, vessel attenuation, SNR and CNR were significantly higher in the 100 kV groups than in the 120 kV groups (p < 0.05). A measure of chest circumference can be used to adapt tube voltage and current for individualized radiation dose control, with resultant similar image noise and sustained diagnostic image quality.

  6. A comparative study of seed localization and dose calculation on pre- and post-implantation ultrasound and CT images for low-dose-rate prostate brachytherapy

    Science.gov (United States)

    Ali, Imad; Algan, Ozer; Thompson, Spencer; Sindhwani, Puneet; Herman, Terence; Cheng, Chih-Yao; Ahmad, Salahuddin

    2009-09-01

    This work investigates variation in the volume of the prostate measured at different stages through the prostate brachytherapy procedure for 30 patients treated with I-125 radioactive seeds. The implanted seeds were localized on post-implantation ultrasound (US) images and the effect of prostate enlargement due to edema on dose coverage for 15 patients was studied. The volume of the prostate was measured at four stages as follows: (a) 2-3 weeks prior to implantation using US imaging, (b) then at the start of the intra-operative prostate brachytherapy procedure on the day of the implant, (c) immediately post-implantation using US imaging in the operating room and (d) finally by CT imaging at nearly 4 weeks post-implantation. Comparative prostate volume studies were performed using US imaging stepper and twister modes. For the purpose of this study, the implanted seeds were localized successfully on post-implant ultrasound twister images, retrospectively. The plans using post-implant US imaging were compared with intra-operative plans on US and plans created on CT images. The prostate volume increases about 10 cm3 on average due to edema induced by needle insertion and seed loading during implantation. The visibility of the implanted seeds on US twister images acquired post-implantation is as good as those on CT images and can be localized and used for dose calculation. The dose coverage represented by parameters such as D90 (dose covering 90% of the volume) and V100 (volume covered by 100% dose) is poorer on plans performed on post-implantation twister US studies than on the intra-operative live plan or the CT scan performed 4 weeks post-operatively. For example, the mean D90 difference on post-implantation US is lower by more than 15% than that on pre-implantation US. The volume enlargement of the prostate due to edema induced by needle insertion and seed placement has a significant effect on the quality of dosimetric coverage in brachytherapy prostate seed

  7. 腰椎多层螺旋CT低剂量扫描参数优化的研究%Study of Multi-slice Spiral CT Low-dose Scanning Parameters Optimization in the Lumbar Spine

    Institute of Scientific and Technical Information of China (English)

    董艳军; 张磊磊; 唐晓; 白男男; 胡蓬勃; 郭兰田

    2014-01-01

    目的:评价不同扫描条件腰椎多层螺旋CT扫描对成像质量及辐射剂量的影响,探讨多层螺旋CT在腰椎软组织病变扫描中适宜的低剂量扫描参数。方法通过CT设备扫描患者腰椎,以240 mAs为起点,逐渐降低管电流量,记录CT主机上显示的辐射剂量;评价图像质量采用adw 4.3工作站,统计学处理采用SPSS18.0软件。结果管电流量80 mAs扫描所获得的图像评分均不低于3分,其产生的辐射剂量为6.81 mGy;而管电流量240 mAs扫描所获得的图像评分均为4分,其产生的辐射剂量为20.22 mGy。结论腰椎软组织多层螺旋CT低剂量扫描的适宜扫描参数为80 mAs。%Objective To evaluate the effect of lumbar spine multiple-slice spiral CT different scanning schemes on image quality and radiation dose and investigate the suitable low-dose scanning parameters of multiple-slice spiral CT in lumbar spine soft tis-sue lesions. Methods We scanned the patients' lumbar spine by CT equipment. We started with 240mAs and gradually reduced mAs. We also recorded the radiation dose showed by the CT host computer and evaluated image quality by the adw 4.3 worksta-tion. We analyzed data through SPSS 18.0. Results All image quality scores were no less than 3 points at 80mAs, and the radia-tion dose at 80mAs was 6.81mGy. All image quality scores were 4 points at 240mAs, and the radiation dose at 240mAs was 20.22mGy. Conclusion The suitable multiple-slice spiral CT low-dose scanning parameters in the lumbar spine soft tissue lesions is 80mAs.

  8. Preliminary performance of image quality for a low-dose C-arm CT system with a flat-panel detector

    Energy Technology Data Exchange (ETDEWEB)

    Kyung Cha, Bo [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of); Seo, Chang-Woo [Department of Radiation Convergence Engineering, College of Health Science, Yonsei University, Wonju (Korea, Republic of); Yang, Keedong [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of); Jeon, Seongchae, E-mail: sarim@keri.re.kr [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of); Huh, Young [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of)

    2015-06-01

    Digital flat panel imager (FPI)-based cone-beam computed tomography (CBCT) has been widely used in C-arm imaging for spine surgery and interventional procedures. The system provides real-time fluoroscopy with high spatial resolution and three-dimensional (3D) visualization of anatomical structure without the need for patient transportation in interventional suite. In this work, a prototype CBCT imaging platform with continuous single rotation about the gantry was developed by using a large-area flat-panel detector with amorphous Si-based thin film transistor matrix. The different 2D projection images were acquired during constant gantry velocity for reconstructed images at a tube voltage of 80–120 kVp, and different current (10–50 mA) conditions. Various scan protocols were applied to a chest phantom human by changing the number of projection images and scanning angles. The projections were then reconstructed into a volumetric data of sections by using a 3D reconstruction algorithm (e.g., filtered back projection). The preliminary quantitative X-ray performance of our CBCT system was investigated by using the American Association of Physicists in Medicine CT phantom in terms of spatial resolution, contrast resolution, and CT number linearity for mobile or fixed C-arm based CBCT application with limited rotational geometry. The novel results of the projection data with different scanning angles and angular increments in the orbital gantry platform were acquired and evaluated experimentally.

  9. Preliminary performance of image quality for a low-dose C-arm CT system with a flat-panel detector

    Science.gov (United States)

    Kyung Cha, Bo; Seo, Chang-Woo; Yang, Keedong; Jeon, Seongchae; Huh, Young

    2015-06-01

    Digital flat panel imager (FPI)-based cone-beam computed tomography (CBCT) has been widely used in C-arm imaging for spine surgery and interventional procedures. The system provides real-time fluoroscopy with high spatial resolution and three-dimensional (3D) visualization of anatomical structure without the need for patient transportation in interventional suite. In this work, a prototype CBCT imaging platform with continuous single rotation about the gantry was developed by using a large-area flat-panel detector with amorphous Si-based thin film transistor matrix. The different 2D projection images were acquired during constant gantry velocity for reconstructed images at a tube voltage of 80-120 kVp, and different current (10-50 mA) conditions. Various scan protocols were applied to a chest phantom human by changing the number of projection images and scanning angles. The projections were then reconstructed into a volumetric data of sections by using a 3D reconstruction algorithm (e.g., filtered back projection). The preliminary quantitative X-ray performance of our CBCT system was investigated by using the American Association of Physicists in Medicine CT phantom in terms of spatial resolution, contrast resolution, and CT number linearity for mobile or fixed C-arm based CBCT application with limited rotational geometry. The novel results of the projection data with different scanning angles and angular increments in the orbital gantry platform were acquired and evaluated experimentally.

  10. CT identification of abdominal injuries in abused pre-school-age children

    Energy Technology Data Exchange (ETDEWEB)

    Hilmes, Melissa A.; Hernanz-Schulman, Marta; Kan, J.H. [Vanderbilt Children' s Hospital, Department of Radiology and Radiological Sciences, Nashville, TN (United States); Greeley, Christopher S. [University of Texas Health Science Center at Houston, Department of Pediatrics, Houston, TX (United States); Piercey, Lisa M. [Vanderbilt Children' s Hospital, Department of Pediatrics, Nashville, TN (United States); Yu, Chang [Vanderbilt University, Department of Biostatistics, Nashville, TN (United States)

    2011-05-15

    Although the abdominopelvic CT findings of abdominal trauma in children have been described, little has been written about the subset of children who are victims of abuse. Our purpose is to describe abdominopelvic injuries in abused pre-school-age children as identified on CT. An IRB-approved retrospective review of our institutional child abuse registry was performed. Searching a 14-year period, we identified 84 children {<=} 5 years of age with medically diagnosed abuse who underwent CT. We reviewed imaging studies, operative reports, autopsy findings and patient outcomes. Consensus review of the CT examinations was performed by CAQ-certified pediatric radiologists, and findings were categorized as normal or by injury types (solid organ versus bowel). The injuries were analyzed in light of existing literature on pediatric accidental and non-accidental injuries. Of the 84 children, 35 (41.7%) had abdominal injuries. Abdominal injuries included liver (15), bowel (13), mesentery (4), spleen (6), kidneys (7), pancreas (4) and adrenal glands (3). Of these children, 26% (9/35) required surgical intervention for bowel, mesenteric and pancreatic injuries. Another 9/35 children died, not as a result of abdominal injuries but as a direct result of inflicted intracranial injuries. Our data indicate that abdominal injuries in abused children present in a pattern similar to that of children with accidental abdominal trauma, underscoring the need for vigilance and correlative historical and clinical data to identify victims of abuse. Mortality in abused children with intra-abdominal injury was frequently related to concomitant head injury. (orig.)

  11. Curved Needles in CT-Guided Fine Needle Biopsies of Abdominal and Retroperitoneal Small Lesions.

    Science.gov (United States)

    De Filippo, Massimo; Saba, Luca; Rossi, Enrica; Nizzoli, Rita; Tiseo, Marcello; Pedrazzi, Giuseppe; Brunese, Luca; Rotondo, Antonio; Rossi, Cristina

    2015-12-01

    To demonstrate the advantages of using curved needles in fine needle aspiration (FNA) with CT-guided, for analyzing abdominal and/or retroperitoneal small lesions which are impossible to reach with conventional non-surgical biopsy techniques, particularly in cases in which the cytology sample was not possible to obtain by means of US or CT guide with axial images. An authorization for CT-guided FNA in patients with neoplasms is not required by the institutional review board of our Institute. From April 2012 to November 2014, the study included retrospectively 25 patients (16 M, 9 F) who underwent CT-guided FNA of abdominal and/or retroperitoneal small lesions (biopsy procedure because of the interposition of anatomical obstacles. Patients with suspected lymphomas or sarcomas, pediatric patients and patients with bleeding diathesis were excluded. Cytology reports were used for evaluating suitability. The biological material was considered to be suitable for cytological study, with a diagnostic value in all 25 cases, finding in particular: out of 23 neoplastic lesions (85%), 21 were malignant (90.2%) and 2 were benign (8%). 2 out 25 were non-neoplastic benign lesions (8%). No procedural complications arose in any of the cases (0%). Using curved needles, there is an effective improvement in CT-guided FNA of abdominal and retroperitoneal small lesions which are difficult to achieve with conventional CT or ultrasound guide.

  12. Predictors for the selection of patients for abdominal CT after blunt trauma: a proposal for a diagnostic algorithm.

    NARCIS (Netherlands)

    Deunk, J.; Brink, M.; Dekker, H.M.; Kool, D.R.; Blickman, J.G.; Vugt, A.B. van; Edwards, M.J.R.

    2010-01-01

    OBJECTIVE: To select parameters that can predict which patients should receive abdominal computed tomography (CT) after high-energy blunt trauma. SUMMARY BACKGROUND DATA: Abdominal CT accurately detects injuries of the abdomen, pelvis, and lumbar spine, but has important disadvantages. More evidence

  13. Low-dose Imaging Technology and Its Application under New 64-Slice CT Generation%后64排CT时代的低剂量成像技术和应用现状

    Institute of Scientific and Technical Information of China (English)

    陈星; 张唯唯; 张华

    2013-01-01

    To keep radiation dose as low as reasonably low remains the most important and challenging strategy for the potential risk of cancer induction from CT scan. This paper reviews the latest techniques to effectively reduce the radiation dose and discuss the low dose management strategy for routine clinical applications.%维持CT扫描过程中的放射剂量在一个合理的低范围,从而减少致癌因素,是目前最重要和最具挑战性的课题.本文重点介绍了最新有效降低放射剂量的技术,以及讨论日常临床应用中有效低放射剂量的管理策略.

  14. 家兔肝脏低剂量CT灌注成像的可行性研究%The feasibility study of hepatic low-dose CT perfusion imaging in rabbit

    Institute of Scientific and Technical Information of China (English)

    杨茹; 胡富碧; 吴少平; 冯俊榜; 宋晓琴; 张志; 曾雪琴

    2015-01-01

    Objective:To explore the effect of hepatic lose-dose CT perfusion imaging for perfusion parameters and image qual-ity. Methods:9 rabbits were undergone routine dose,median dose and low-dose CT perfusion scanning. The original images were pro-cessed by perfusion software. The value of blood volume ( BV) ,blood flow ( BF) and arterial liver perfusion ( ALP) were measured and image quality were evaluated, and statistical analysis was performed. Results:The differences of BF, BV, and ALP among the three groups were not statistically significant (P>0. 05). The scores of image quality in routine dose group,median dose group and low-dose group were 4. 11 ± 0. 65,4. 38 ± 0. 61 and 4. 56 ± 0. 58,respectively. The two reviewers keep good consistency. Kappa value of two re-viewers was 0. 507. Compared with the routine dose group,the value of CTDIvol and DLP of the low-dose group decreased 75%. Con-clusion:Low-dose hepatic CT perfusion imaging based on reducing tube current in rabbit was feasible.%目的::探讨低剂量CT灌注成像对家兔肝脏灌注成像参数及图像质量的影响。方法:对9只家兔行常规剂量、中等剂量和低剂量肝脏CT灌注成像,对图像进行后处理,测量肝脏灌注参数值,包括肝血容量( BV)、肝血流量( BF)、肝动脉灌注量( APL),并对获得的肝脏灌注图进行主观质量评分,对3组灌注参数值和图像质量评分进行统计学分析。同时记录三种条件下的辐射记录值。结果:低剂量组、中等剂量组和常规剂量组的BF、BV、APL值差异无统计学意义( P>0.05)。低剂量组、中等剂量组和常规剂量组图像主观评分分别为(4.11±0.65)分、(4.38±0.61)分和(4.56±0.58)分,2名医师观察者间一致性较好(Kappa值为0.507)。低剂量组所接受辐射剂量远低于常规记录,容积CT剂量指数(volume CT dose index, CTDI-vol)和剂量长度乘积( dose length product,DLP)均下降了75%。结论:基于降低管电

  15. SU-F-18C-13: Low-Dose X-Ray CT Reconstruction Using a Hybrid First-Order Method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L; Lin, W [Tianjin University, Tianjin (China); Jin, M [University of Texas at Arlington, Arlington, TX (United States)

    2014-06-15

    Purpose: To develop a novel reconstruction method for X-ray CT that can lead to accurate reconstruction at significantly reduced dose levels combining low X-ray incident intensity and few views of projection data. Methods: The noise nature of the projection data at low X-ray incident intensity was modeled and accounted by the weighted least-squares (WLS) criterion. The total variation (TV) penalty was used to mitigate artifacts caused by few views of data. The first order primal-dual (FOPD) algorithm was used to minimize TV in image domain, which avoided the difficulty of the non-smooth objective function. The TV penalized WLS reconstruction was achieved by alternated FOPD TV minimization and projection onto convex sets (POCS) for data fidelity constraints. The proposed FOPD-POCS method was evaluated using the FORBILD jaw phantom and the real cadaver head CT data. Results: The quantitative measures, root mean square error (RMSE) and contrast-to-noise ratio (CNR), demonstrate the superior denoising capability of WLS over LS-based TV iterative reconstruction. The improvement of RMSE (WLS vs. LS) is 15%∼21% and that of CNR is 17%∼72% when the incident counts per ray are ranged from 1×10{sup 5} to 1×10{sup 3}. In addition, the TV regularization can accurately reconstruct images from about 50 views of the jaw phantom. The FOPD-POCS reconstruction reveals more structural details and suffers fewer artifacts in both the phantom and real head images. The FOPD-POCS method also shows fast convergence at low X-ray incident intensity. Conclusion: The new hybrid FOPD-POCS method, based on TV penalized WLS, yields excellent image quality when the incident X-ray intensity is low and the projection views are limited. The reconstruction is computationally efficient since the FOPD minimization of TV is applied only in the image domain. The characteristics of FOPD-POCS can be exploited to significantly reduce radiation dose of X-ray CT without compromising accuracy for diagnosis

  16. Extra-appendiceal findings in pediatric abdominal CT for suspected appendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Halverson, Mark; Delgado, Jorge; Mahboubi, Soroosh [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2014-07-15

    Much has been written regarding the incidence, types, importance and management of abdominal CT incidental findings in adults, but there is a paucity of literature on incidental findings in children. We sought to determine the prevalence and characteristics of extra-appendiceal and incidental findings in pediatric abdominal CT performed for suspected appendicitis. A retrospective review was performed of abdominal CT for suspected appendicitis in a pediatric emergency department from July 2010 to June 2012. Extra-appendiceal findings were recorded. Any subsequent imaging was noted. Extra-appendiceal findings were divided into incidental findings of doubtful clinical significance, alternative diagnostic findings potentially providing a diagnosis other than appendicitis explaining the symptoms, and incidental findings that were abnormalities requiring clinical correlation and sometimes requiring further evaluation but not likely related to the patient symptoms. One hundred sixty-five children had abdominal CT for suspected appendicitis. Seventy-seven extra-appendiceal findings were found in 57 (34.5%) patients. Most findings (64 of 77) were discovered in children who did not have appendicitis. Forty-one of these findings (53%) could potentially help explain the patient's symptoms, while 30 of the findings (39%) were abnormalities that were unlikely to be related to the symptoms but required clinical correlation and sometimes further work-up. Six of the findings (8%) had doubtful or no clinical significance. Extra-appendiceal findings are common in children who undergo abdominal CT in the setting of suspected appendicitis. A significant percentage of these patients have findings that help explain their symptoms. Knowledge of the types and prevalence of these findings may help radiologists in the planning and interpretation of CT examinations in this patient population. (orig.)

  17. Validation of the Measurement of Intra-abdominal Fat Between Ultrasound and CT Scan in Women with Obesity and Infertility

    NARCIS (Netherlands)

    Kuchenbecker, Walter K. H.; Groen, Henk; Pel, Heleen; Bolster, Johanna H. T.; Wolffenbuttel, Bruce H. R.; Land, Jolande A.; Hoek, Annemieke; Corpeleijn, Eva

    2014-01-01

    Objective: To compare the means and changes over time of intra-abdominal fat (IAF) and subcutaneous abdominal fat (SAF) measured by abdominal ultrasound (US) and computerized tomography (CT). Design and Methods: Prospective cohort study of 53 women with obesity and infertility undergoing a lifestyle

  18. Validation of the Measurement of Intra-abdominal Fat Between Ultrasound and CT Scan in Women with Obesity and Infertility

    NARCIS (Netherlands)

    Kuchenbecker, Walter K. H.; Groen, Henk; Pel, Heleen; Bolster, Johanna H. T.; Wolffenbuttel, Bruce H. R.; Land, Jolande A.; Hoek, Annemieke; Corpeleijn, Eva

    Objective: To compare the means and changes over time of intra-abdominal fat (IAF) and subcutaneous abdominal fat (SAF) measured by abdominal ultrasound (US) and computerized tomography (CT). Design and Methods: Prospective cohort study of 53 women with obesity and infertility undergoing a lifestyle

  19. Using cone-beam CT as a low-dose 3D imaging technique for the extremities: initial experience in 50 subjects

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ambrose J.; Chang, Connie Y.; Palmer, William E. [Massachusetts General Hospital, Department of Radiology, Division of Musculoskeletal Imaging and Intervention, Boston, MA (United States); Thomas, Bijoy J. [Universal College of Medical Sciences, Department of Radiology, Bhairahawa (Nepal); MacMahon, Peter J. [Mater Misericordiae University Hospital, Department of Radiology, Dublin 7 (Ireland)

    2015-06-01

    To prospectively evaluate a dedicated extremity cone-beam CT (CBCT) scanner in cases with and without orthopedic hardware by (1) comparing its imaging duration and image quality to those of radiography and multidetector CT (MDCT) and (2) comparing its radiation dose to that of MDCT. Written informed consent was obtained for all subjects for this IRB-approved, HIPAA-compliant study. Fifty subjects with (1) fracture of small bones, (2) suspected intraarticular fracture, (3) fracture at the site of complex anatomy, or (4) a surgical site difficult to assess with radiography alone were recruited and scanned on an extremity CBCT scanner prior to FDA approval. Same-day radiographs were performed in all subjects. Some subjects also underwent MDCT within 1 month of CBCT. Imaging duration and image quality were compared between CBCT and radiographs. Imaging duration, effective radiation dose, and image quality were compared between CBCT and MDCT. Fifty-one CBCT scans were performed in 50 subjects. Average imaging duration was shorter for CBCT than radiographs (4.5 min vs. 6.6 min, P = 0.001, n = 51) and MDCT (7.6 min vs. 10.9 min, P = 0.01, n = 7). Average estimated effective radiation dose was less for CBCT than MDCT (0.04 mSv vs. 0.13 mSv, P = 0.02, n = 7). CBCT images yielded more diagnostic information than radiographs in 23/51 cases and more diagnostic information than MDCT in 1/7 cases, although radiographs were superior for detecting hardware complications. CBCT performs high-resolution imaging of the extremities using less imaging time than radiographs and MDCT and lower radiation dose than MDCT. (orig.)

  20. Clinical value of a one-stop-shop low-dose lung screening combined with {sup 18}F-FDG PET/CT for the detection of metastatic lung nodules from colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yeon Hee; Lim, Seok Tae; Jeong, Hwan Jeong; Sohn, Myung Hee [Dept. of Nuclear Medicine, Research Institute of Clinical Medicine, Chonbuk National University-Biomedical Research Institute, Chonbuk National University Hospital, Cyclotron Research Center, Molecular Imaging and Therapeutic Medicine Research Center, Chonbuk National University Medical School and Hospital, Jeonju (Korea, Republic of)

    2016-06-15

    The aim of this study was to evaluate the clinical usefulness of additional low-dose high-resolution lung computed tomography (LD-HRCT) combined with 18F-fluoro-2-deoxyglucose positron emission tomography with CT (18F-FDG PET/CT) compared with conventional lung setting image of 18F-FDG PET/CT for the detection of metastatic lung nodules from colorectal cancer. From January 2011 to September 2011, 649 patients with colorectal cancer underwent additional LD-HRCT at maximum inspiration combined with 18F-FDG PET/CT. Forty-five patients were finally diagnosed to have lung metastasis based on histopathologic study or clinical follow-up. Twenty-five of the 45 patients had ≤5 metastatic lung nodules and the other 20 patients had  >5 metastatic nodules. One hundred and twenty nodules in the 25 patients with ≤5 nodules were evaluated by conventional lung setting image of 18F-FDG PET/CT and by additional LD-HRCT respectively. Sensitivities, specificities, diagnostic accuracies, positive predictive values (PPVs), and negative predictive values (NPVs) of conventional lung setting image of 18F-FDG PET/CT and additional LD-HRCT were calculated using standard formulae. The McNemar test and receiver-operating characteristic (ROC) analysis were performed. Of the 120 nodules in the 25 patients with ≤5 metastatic lung nodules, 66 nodules were diagnosed as metastatic. Eleven of the 66 nodules were confirmed histopathologically and the others were diagnosed by clinical follow-up. Conventional lung setting image of 18F-FDG PET/CT detected 40 of the 66 nodules and additional LD-HRCT detected 55 nodules. All 15 nodules missed by conventional lung setting imaging but detected by additional LD-HRCT were <1 cm in size. The sensitivity, specificity, and diagnostic accuracy of the modalities were 60.6 %, 85.2 %, and 71.1 % for conventional lung setting image and 83.3 %, 88.9 %, and 85.8 % for additional LD-HRCT. By ROC analysis, the area under the ROC curve (AUC) of conventional

  1. Abdominal and pelvic computed tomography (CT) interpretation: discrepancy rates among experienced radiologists

    Energy Technology Data Exchange (ETDEWEB)

    Abujudeh, Hani H.; Boland, Giles W.; Kaewlai, Rathachai; Rabiner, Pavel; Thrall, James H. [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Halpern, Elkarn F.; Gazelle, G.S. [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Massachusetts General Hospital and Harvard Medical School, Institute for Technology Assessment, Boston, MA (United States)

    2010-08-15

    To assess the discrepancy rate for the interpretation of abdominal and pelvic computed tomography (CT) examinations among experienced radiologists. Ninety abdominal and pelvic CT examinations reported by three experienced radiologists who specialize in abdominal imaging were randomly selected from the radiological database. The same radiologists, blinded to previous interpretation, were asked to re-interpret 60 examinations: 30 of their previous interpretations and 30 interpreted by others. All reports were assessed for the degree of discrepancy between initial and repeat interpretations according to a three-level scoring system: no discrepancy, minor, or major discrepancy. Inter- and intrareader discrepancy rates and causes were evaluated. CT examinations included in the investigation were performed on 90 patients (43 men, mean age 59 years, SD 14, range 19-88) for the following indications: follow-up/evaluation of malignancy (69/90, 77%), pancreatitis (5/90, 6%), urinary tract stone (4/90, 4%) or other (12/90, 13%). Interobserver and intraobserver major discrepancy rates were 26 and 32%, respectively. Major discrepancies were due to missed findings, different opinions regarding interval change of clinically significant findings, and the presence of recommendation. Major discrepancy of between 26 and 32% was observed in the interpretation of abdominal and pelvic CT examinations. (orig.)

  2. Abdominal CT scanning in reproductive-age women with right lower quadrant abdominal pain: does its use reduce negative appendectomy rates and healthcare costs?

    Science.gov (United States)

    Morse, Bryan C; Roettger, Richard H; Kalbaugh, Corey A; Blackhurst, Dawn W; Hines, William B

    2007-06-01

    Although acute appendicitis is the most frequent cause of the acute abdomen in the United States, its accurate diagnosis in reproductive-age women remains difficult. Problems in making the diagnosis are evidenced by negative appendectomy rates in this group of 20 per cent to 45 per cent. Abdominal CT scanning has been used in diagnosing acute appendicitis, but its reliability and usefulness remains controversial. There is concern that the use of CT scanning to make this diagnosis leads to increased and unwarranted healthcare charges and costs. The purpose of our study is to determine if abdominal CT scanning is an effective test in making the diagnosis of acute appendicitis in reproductive-age women (age, 16-49 years) with right lower quadrant abdominal pain and to determine if its use is cost-effective. From January 2003 to December 2006, 439 patients were identified from our academic surgical database and confirmed by chart review as undergoing an appendectomy with a pre- or postoperative diagnosis of acute appendicitis. Data, including age, presence and results of preoperative abdominal CT scans, operative findings, and pathology reports were reviewed. Comparison of patients receiving a preoperative CT scan with those who did not was performed using chi-squared analysis. In the subgroup of reproductive-age women, there was a significant difference in negative appendectomy rates of 17 per cent in the group that received abdominal CT scans versus 42 per cent in the group that did not (P accounting for the patient and insurance company costs, abdominal CT scan savings averaged $1412 per patient. Abdominal CT scanning is a reliable, useful, and cost-effective test for evaluating right lower quadrant abdominal pain and making the diagnosis of acute appendicitis in reproductive-age women.

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

    Science.gov (United States)

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

    2015-10-01

    iterative reconstruction. Use of the ASIR-V algorithm decreased image noise and increased image quality when compared with the ASIR and FBP methods. These results suggest that high-quality low-dose CT may represent a new clinical option.

  4. Acute Appendagitis Presenting with Features of Appendicitis: Value of Abdominal CT Evaluation

    Directory of Open Access Journals (Sweden)

    Sukhpreet Dubb

    2008-05-01

    Full Text Available We report a case of acute appendagitis in a patient who presented initially with typical features of acute appendicitis. The diagnosis of acute appendagitis was made on pathognomonic signs on computed tomography (CT scan. Abdominal pain is a common surgical emergency. CT is not always done if there are clear features of acute appendicitis. The rare but important differential diagnosis of acute appendagitis must be borne in mind when dealing with patients with suspected acute appendicitis. A CT scan of the abdomen may avoid unnecessary surgery in these patients.

  5. The clinical application of multi-slice spiral CT angiography in abdominal aortic disease

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective: To evaluate the clinical application of multi-slice spiral CT angiography(MSCTA) in the assessment of abdominal aortic disease. Methods: Fifty-four patients underwent multi-slice spiral CT angiography of abdomen. Contrast agent (Omnipaque 300 I g/L) 1.5 ml/kg was injected and the injection rate was 3 ml/s. The delay time was determined by bolus tracking technique,Tll level abdominal aorta was set as the target vessel and the threshold was 180-200 Hu, slice width was 3 mm and with a pitch of 4-6.Original data were transferred to working-station to perform functional reconstruction. Results: Ten cases were normal, twenty-eight cases were abdominal aortic aneurysms, five abdominal aortic dissecting aneurysms (Debakay type Ⅲ ) and eleven aortic sclerosis. SSD showed the body of aneurysm and the relationship between aneurysm and adjacent blood vessel, MIP better displayed calcification of blood vessel wall and condition of the stent, MPR demonstrated true and false lumen, rupture site of abdominal aorta intima and mural thrombus. Conclusion: MSCTA axial and reconstruction image can show the extent of abdominal aortic disease and the relationship with adjacent blood vessels. It is a safe, simple and non-invasive examination method.

  6. Acute ureteric calculus obstruction: unenhanced spiral CT versus HASTE MR urography and abdominal radiograph.

    Science.gov (United States)

    Regan, F; Kuszyk, B; Bohlman, M E; Jackman, S

    2005-06-01

    The aim of this study is to compare the performance of unenhanced spiral CT to the combination of HASTE MR urography (MRU) and plain abdominal radiography (KUB) in patients suspected of having acute calculus ureteric obstruction. 64 patients with suspected acute calculus ureteric obstruction were evaluated. The presence of perirenal fluid, presence and level of ureteric obstruction and calculi were assessed on both techniques. 44 of 64 (69%) patients had acute calculus ureteric obstruction based on clinical, radiographic or surgical findings. MRU showed perirenal fluid in acute ureteric obstruction (77%) with a greater sensitivity than CT showed stranding (45%). The combination of fluid and ureteric dilation on MRU showed a sensitivity of 93% (CT 80%), specificity of 95% (CT 85%), and accuracy of 94% (CT 81%). There were 61 findings of either fluid or ureteric dilatation on MRU in 44 acutely obstructed kidneys compared with 37 similar findings on CT (p0.75) in the finding of perirenal fluid on MRU, there was only fair interobserver agreement (KappaMRU/KUB showed ureteric calculi in 21/29 (72%) of patients with calculi seen by CT. Overall, MRU/KUB revealed 2.4 abnormalities per acutely obstructed ureter compared with 1.8 abnormalities detected by CT. MRU/KUB using HASTE sequences can diagnose the presence of acute calculus ureteric obstruction with similar accuracy to spiral CT. The technique has less observer variability and is more accurate than CT in detecting evidence of obstruction such as perirenal fluid.

  7. CT diagnosis of inflammatory abdominal aneurysms. Computertomographische Diagnostik des inflammatorischen Bauchaortenaneurysmas

    Energy Technology Data Exchange (ETDEWEB)

    Koch, J.A. (Inst. fuer Diagnostische Radiologie, Duesseldorf Univ. (Germany)); Gruetzner, G. (Inst. fuer Diagnostische Radiologie, Duesseldorf Univ. (Germany)); Jungblut, R.M. (Inst. fuer Diagnostische Radiologie, Duesseldorf Univ. (Germany)); Kniemeyer, H.W. (Abt. fuer Gefaesschirurgie und Nierentransplantation, Duesseldorf Univ. (Germany)); Moedder, U. (Inst. fuer Diagnostische Radiologie, Duesseldorf Univ. (Germany))

    1994-07-01

    Amongst 1599 patients undergoing surgery for abdominal aortic aneurysm, there were 89 patients (5,6%) who showed typical features of inflammatory aneurysms of the abdominal aorta (IAAA). 37 of the 89 patients had been examined preoperatively by CT. In 73% of the cases (27/37) a correct diagnosis had been made. Localisation, width and extent of the IAAA was correctly diagnosed in all patients. Involvement of the renal arteries by the inflammatory process, the extent of thrombus and of mural calcification were accurately shown. The inflammatory tissues were typically ventral and lateral to the aorta. Frequently, there were adhesions to neighbouring structures. Aortic rupture, aortic dissection and retroperitoneal lymphoma may produce similar CT appearances; nevertheless, CT remains at present the method of choice for the diagnosis of IAAA because of its high sensitivity. (orig.)

  8. Colitis detection on abdominal CT scans by rich feature hierarchies

    Science.gov (United States)

    Liu, Jiamin; Lay, Nathan; Wei, Zhuoshi; Lu, Le; Kim, Lauren; Turkbey, Evrim; Summers, Ronald M.

    2016-03-01

    Colitis is inflammation of the colon due to neutropenia, inflammatory bowel disease (such as Crohn disease), infection and immune compromise. Colitis is often associated with thickening of the colon wall. The wall of a colon afflicted with colitis is much thicker than normal. For example, the mean wall thickness in Crohn disease is 11-13 mm compared to the wall of the normal colon that should measure less than 3 mm. Colitis can be debilitating or life threatening, and early detection is essential to initiate proper treatment. In this work, we apply high-capacity convolutional neural networks (CNNs) to bottom-up region proposals to detect potential colitis on CT scans. Our method first generates around 3000 category-independent region proposals for each slice of the input CT scan using selective search. Then, a fixed-length feature vector is extracted from each region proposal using a CNN. Finally, each region proposal is classified and assigned a confidence score with linear SVMs. We applied the detection method to 260 images from 26 CT scans of patients with colitis for evaluation. The detection system can achieve 0.85 sensitivity at 1 false positive per image.

  9. Systematic unenhanced CT for acute abdominal symptoms in the elderly patients improves both emergency department diagnosis and prompt clinical management

    Energy Technology Data Exchange (ETDEWEB)

    Millet, Ingrid; Pages-Bouic, Emma; Curros-Doyon, Fernanda; Taourel, Patrice [CHU Lapeyronie, Department of Medical Imaging, Montpellier Cedex 5 (France); Sebbane, Mustapha [Department of Emergency Medicine, CHU Lapeyronie, Montpellier (France); Molinari, Nicolas [Department of Medical Information and Statistics, CHU Montpellier (France); Riou, Bruno [GH Pitie-Salpetriere, APHP, Department of Emergency Medicine and Surgery, Paris (France)

    2017-02-15

    To assess the added-value of systematic unenhanced abdominal computed tomography (CT) on emergency department (ED) diagnosis and management accuracy compared to current practice, in elderly patients with non-traumatic acute abdominal symptoms. Institutional review board approval and informed consent were obtained. This prospective study included 401 consecutive patients 75 years of age or older, admitted to the ED with acute abdominal symptoms, and investigated by early systematic unenhanced abdominal CT scan. ED diagnosis and intended management before CT, after unenhanced CT, and after contrast CT if requested, were recorded. Diagnosis and management accuracies were evaluated and compared before CT (clinical strategy) and for two conditional strategies (current practice and systematic unenhanced CT). An expert clinical panel assigned a final diagnosis and management after a 3-month follow-up. Systematic unenhanced CT significantly improved the accurate diagnosis (76.8% to 85%, p=1.1 x 10{sup -6}) and management (88.5% to 95.8%, p=2.6 x 10{sup -6}) rates compared to current practice. It allowed diagnosing 30.3% of acute unsuspected pathologies, 3.4% of which were unexpected surgical procedure requirement. Systematic unenhanced abdominal CT improves ED diagnosis accuracy and appropriate management in elderly patients presenting with acute abdominal symptoms compared to current practice. (orig.)

  10. Routine use of modified CT Enterography in patients with acute abdominal pain

    Energy Technology Data Exchange (ETDEWEB)

    Gourtsoyianni, Sofia [Department of Radiology, University Hospital of Heraklion, Medical School of Crete, 71110 Stavrakia, Heraklion/Crete (Greece)], E-mail: sgty76@gmail.com; Zamboni, Giulia A. [Department of Radiology, University Hospital GB Rossi, Verona (Italy); Romero, Janneth Y.; Raptopoulos, Vassilios D. [Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (United States)

    2009-03-15

    Purpose: To evaluate routine use of CT Enterography (CTE) in patients presenting with non-traumatic acute abdominal pain with respect to patient tolerance, imaging of intestinal detail along with conventional abdominal evaluation. Materials and methods: Modified CTE was performed in 165 consecutive patients with acute abdominal pain: ingestion, as tolerated, of 900-1200 ml of 2% barium suspension + 5 ml of Gastrografin over 45 min; 150 ml of iv contrast given in two boluses (50 and 100 ml) 3 min apart (split bolus injection protocol). Axial, coronal and sagittal reformats were reviewed by two radiologists and graded on a 5-point scale (5 best) in regard to GI tract luminal opacification and distension and abdominal organ and vascular enhancement. Results: In 81 patients the cause of abdominal pain was identified (intestinal in 54 and extraintestinal in 27). Oral contrast reached cecum in 76% of the patients and the small bowel was well distended and opacified (medians = 4). Mucosa detail was good (median = 3) and there was significant (p < 0.0001) correlation between bowel opacification and distension for both jejunum and ileum. A combined nephrographic and excretory phase was achieved (medians 4 and 5, respectively), while the great vessels were well opacified, allowing for vascular evaluation (median = 5). The rest of the abdominal structures were well visualized. Conclusion: Modified CTE is well tolerated by patients with acute non-traumatic abdominal pain, and can be used routinely as a non-invasive examination informative of bowel, vessel and organ pathology in Emergency Department patients.

  11. Role of F-18 FDG PET/CT in the management of infected abdominal aortic aneurysm due to salmonella

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seung Jin; Lee, Jin Soo; Cheong, Moon Hyun; Byun, Sung Su; Hyun, In Young [Inha University College of Medicine, Incheon (Korea, Republic of)

    2007-12-15

    We present a case of infected abdominal aortic aneurysm due to salmonella enteritidis. F-18 FDG PET/CT was performed to diagnosis and during follow-up after antibiotic treatment. Computed tomography (CT) is considered to be the best diagnostic imaging modality in infected aortic lesions. In this case, a combination of CT and FDG PET/CT provided accurate information for the diagnosis of infected abdominal aortic aneurysm. Moreover, FDG PET/CT made an important contribution of monitoring disease activity during antibiotic treatment.

  12. Abdominal fat volume estimation by stereology on CT: a comparison with manual planimetry

    Energy Technology Data Exchange (ETDEWEB)

    Manios, G.E.; Mazonakis, M.; Damilakis, J. [University of Crete, Department of Medical Physics, Faculty of Medicine, Heraklion, Crete (Greece); Voulgaris, C.; Karantanas, A. [University of Crete, Department of Radiology, Faculty of Medicine, Heraklion, Crete (Greece)

    2016-03-15

    To deploy and evaluate a stereological point-counting technique on abdominal CT for the estimation of visceral (VAF) and subcutaneous abdominal fat (SAF) volumes. Stereological volume estimations based on point counting and systematic sampling were performed on images from 14 consecutive patients who had undergone abdominal CT. For the optimization of the method, five sampling intensities in combination with 100 and 200 points were tested. The optimum stereological measurements were compared with VAF and SAF volumes derived by the standard technique of manual planimetry on the same scans. Optimization analysis showed that the selection of 200 points along with the sampling intensity 1/8 provided efficient volume estimations in less than 4 min for VAF and SAF together. The optimized stereology showed strong correlation with planimetry (VAF: r = 0.98; SAF: r = 0.98). No statistical differences were found between the two methods (VAF: P = 0.81; SAF: P = 0.83). The 95 % limits of agreement were also acceptable (VAF: -16.5 %, 16.1 %; SAF: -10.8 %, 10.7 %) and the repeatability of stereology was good (VAF: CV = 4.5 %, SAF: CV = 3.2 %). Stereology may be successfully applied to CT images for the efficient estimation of abdominal fat volume and may constitute a good alternative to the conventional planimetric technique. (orig.)

  13. Clinical significance of pulmonary nodules detected on abdominal CT in pediatric patients

    Energy Technology Data Exchange (ETDEWEB)

    Breen, Micheal; Lee, Edward Y. [Boston Children' s Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Zurakowski, David [Boston Children' s Hospital and Harvard Medical School, Departments of Anesthesiology and Surgery, Boston, MA (United States)

    2015-11-15

    The clinical significance of a pulmonary nodule that is detected incidentally on CT studies in children is unknown. In addition, there is limited information regarding the management of incidentally detected pulmonary nodules discovered on abdominal CT studies in children. The purpose of this study was to investigate the clinical significance of incidental pulmonary nodules detected on abdominal CT studies in children. This was a retrospective study performed following institutional review board approval. Abdominal CT reports in patients younger than 18 years of age from July 2004 to June 2011 were reviewed for the terms ''nodule,'' ''nodular'' or ''mass'' in reference to the lung bases. The study population included those pediatric patients in whom pulmonary nodules were initially detected on abdominal CT studies. The largest pulmonary nodules detected on CT studies were evaluated for their features (size, shape, margin, attenuation, location, and presence of calcification and cavitation). Follow-up CT studies and clinical records were reviewed for demographic information, history of underlying malignancies and the clinical outcome of the incidental pulmonary nodules. Comparison of malignant versus benign pulmonary nodules was performed with respect to the size of the nodule, imaging features on CT, and patient history of malignancy using the Student's t-test and Fisher exact test. Youden J-index in receiver operating characteristic (ROC) analysis was used to determine the optimal cut-off size for suggesting a high risk of malignancy of incidentally detected pulmonary nodules. Pulmonary nodules meeting inclusion criteria were detected in 62 (1.2%) of 5,234 patients. The mean age of patients with nodules was 11.2 years (range: 5 months-18 years). Thirty-one patients (50%) had follow-up CT studies and two of these patients (6%) were subsequently found to have malignant pulmonary nodules. Both of these

  14. Clinical significance of pulmonary nodules detected on abdominal CT in pediatric patients.

    Science.gov (United States)

    Breen, Micheál; Zurakowski, David; Lee, Edward Y

    2015-11-01

    The clinical significance of a pulmonary nodule that is detected incidentally on CT studies in children is unknown. In addition, there is limited information regarding the management of incidentally detected pulmonary nodules discovered on abdominal CT studies in children. The purpose of this study was to investigate the clinical significance of incidental pulmonary nodules detected on abdominal CT studies in children. This was a retrospective study performed following institutional review board approval. Abdominal CT reports in patients younger than 18 years of age from July 2004 to June 2011 were reviewed for the terms "nodule," "nodular" or "mass" in reference to the lung bases. The study population included those pediatric patients in whom pulmonary nodules were initially detected on abdominal CT studies. The largest pulmonary nodules detected on CT studies were evaluated for their features (size, shape, margin, attenuation, location, and presence of calcification and cavitation). Follow-up CT studies and clinical records were reviewed for demographic information, history of underlying malignancies and the clinical outcome of the incidental pulmonary nodules. Comparison of malignant versus benign pulmonary nodules was performed with respect to the size of the nodule, imaging features on CT, and patient history of malignancy using the Student's t-test and Fisher exact test. Youden J-index in receiver operating characteristic (ROC) analysis was used to determine the optimal cut-off size for suggesting a high risk of malignancy of incidentally detected pulmonary nodules. Pulmonary nodules meeting inclusion criteria were detected in 62 (1.2%) of 5,234 patients. The mean age of patients with nodules was 11.2 years (range: 5 months-18 years). Thirty-one patients (50%) had follow-up CT studies and two of these patients (6%) were subsequently found to have malignant pulmonary nodules. Both of these patients had a history of malignancy. Of the remaining 31 patients

  15. Kaposi sarcoma and lymphadenopathy syndrome: limitations of abdominal CT in acquired immunodeficiency syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Moon, K.L. Jr.; Federle, M.P.; Abrams, D.I.; Volberding, P.; Lewis, B.J.

    1984-02-01

    Abdominal computed tomography (CT) was performed in 31 patients with Kaposi sarcoma (KS) related to acquired immunodeficiency syndrome (AIDS), three patients with classic KS, and 12 patients with the newly described lymphadenopathy syndrome (LNS). The frequency, distribution, and appearance of lymphadenopathy and splenomegaly were similar in the AIDS-related KS and LNS groups. Rectal and perirectal disease was identified in 86% of homosexual men studied; rectal KS could not be distinguished from proctitis on CT criteria alone. No CT abnormalities were seen in patients with classic KS. The CT demonstration of retroperitoneal, mesenteric, or pelvic adenopathy or of rectal or perirectal disease in patients with AIDS-related KS is not necessarily indicative of widespread involvement with the disease.

  16. 投影数据恢复导引的非局部平均低剂量CT优质重建%Projection Data Recovery Induced Non-local Means for Low-Dose CT Reconstruction

    Institute of Scientific and Technical Information of China (English)

    刘楠; 黄静; 马建华; 陈武凡; 卢虹冰; Zhengrong Liang

    2011-01-01

    针对低剂量CT成像质量退化问题,将CT投影数据恢复与图像数据恢复巧妙地融合,提出一种投影数据恢复导引的非局部平均(NL-means)低剂量CT重建方法.首先通过非线性Anscombe变换将满足Poisson分布的投影数据转化为Gaussian分布,以便于投影数据噪声的滤除;然后对滤波后的投影数据执行Anscombe逆变换和滤波反投影(FBP)CT图像重建;最后将投影数据滤波后的FBP图像作为先验构建非局部权值矩阵,并将该权值矩阵用于低剂量CT图像的非局部平均成像.仿真和临床实验结果表明.该方法在噪声消除和伪影抑制两方面均有上佳表现.%To improve the quality of low-dose computed tomography (CT) image, a novel projection data recovery induced non-local means for low-dose CT reconstruction is proposed. The presented method can take the advantages of data recovery methods in two domains (projection domain and image domain). Specially, the projection data is first transformed from Poisson distribution to Gaussian distribution using the nonlinear Anscombe transform in order to easily filter the noise of projection data. Second, after Anscombe transformed data is filtered, Anscombe inverse transform is performed, and the reconstructed image is achieved using the classical filtered back projection (FBP) method from filtered projection data. Last, non-local means (NL-means) weights of FBP image are computed from the restored projection data to induce the NL-means filtering of directly reconstructed FBP image from the un-restored projection data. Simulated and clinical experimental results demonstrate that the proposed method performs very well in lowering the noise and preserving the image edge.

  17. CT diagnosis of 52 patients with lymphoma in abdominal lymph nodes

    Institute of Scientific and Technical Information of China (English)

    Ri-Sheng Yu; Wei-Min Zhang; Yi-Qing Liu

    2006-01-01

    AIM: To assess CT manifestations and its diagnostic value for lymphoma in the abdominal lymph nodes (LALN).METHODS: CT findings in 52 cases of LALN proved by surgery or biopsy, including Hodgkin's disease (HD) in 16 cases and non-Hodgkin's lymphoma (NHL) in 36 cases,were retrospectively analyzed.RESULTS: (1) CT manifestations based on distribution of the lesions of LALN: Solitary mass type was found in 10 cases, including solitary, round, uniform-density,enlarged lymph nodes in 3 cases; and multiple, enlarged lymph nodes fusing into singular lobular mass in 7cases. Thirty-four cases of multiple-nodular type showed multiple, round, enlarged lymph nodes with uniform density and clear margins. Vessels-embedded signs,including mesenteric vessels, renal vessels, abdominal aorta or inferior vena cava, were seen in 6 cases, and duodenum-embedded signs were seen in 2 cases. Eight cases of diffuse type showed characteristic "cobblestone signs". (2) CT manifestations correlated with pathological type: CT manifestations of 12 cases of HD were different from those of 40 cases of NHL in distribution, size,quantity and fused lesion of enlarged lymph nodes. (3)Twenty-eight cases of 52 patients were accompanied with extra-nodal lymphoma in the abdomen, especially gastrointestinal lymphoma, which had characteristic CT findings. (4) In follow-up examinations, CT images showed uniform, heterogeneous or rim enhancement in 15 cases, and occasional calcifications accompanied with reduction of the lesion size and quantity in 12 cases, whereas the lesions disappeared in 3 cases after treatment.CONCLUSION: CT images show many characteristic manifestations valuable for qualitative diagnosis of LALN,and it is also helpful for pathological classification of LALN and therapeutic evaluation in follow-up of patients.

  18. Value of abdominal CT in patients of the surgical intensive care unit; Stellenwert der abdominellen CT bei chirurgischen Intensivpatienten

    Energy Technology Data Exchange (ETDEWEB)

    Rieger, J. [Abt. fuer Radiologie, Klinikum Innenstadt, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Kerner, T. [Abt. fuer Chirurgie, Klinikum Innenstadt, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Waydhas, C. [Abt. fuer Chirurgie, Klinikum Innenstadt, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Schenk, F. [Abt. fuer Radiologie, Klinikum Innenstadt, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Pfeifer, K.J. [Abt. fuer Radiologie, Klinikum Innenstadt, Ludwig-Maximilians-Universitaet, Muenchen (Germany)

    1996-09-01

    The purpose of the retrospective study reported was to examine the indications, findings and therapeutic consequences of 88 consecutive CT examinations of the abdomen of 62 patients of a surgical intensive care unit. The CT examinations were performed within 12 hours following indication. The most frequent indications were sepsis with suspected intra-abdominal foci (72.7%), suspected lesion of intra-abdominal organs due to a serious accident (13.6%), and acutely necrotising pancreatitis (11.4%). Clinically relevant findings were obtained in 71.6% of the patients, in 43.2% the decision was for invasive treatment (of 38 patients, 28 treated by surgery, and 10 by other interventional measures) within 48 hours, which meant an essential modification of hitherto planned treatment. Patients with a high MOF score (>5) exhibited a significantly higher rate of pathologic findings than patients with a low MOF score (0-2). In the cases of suspected organ lesions, CT did not add any further information. (orig./MG)

  19. PET/CT imaging of abdominal aorta with intramural hematomas, penetrating ulcer, and saccular pseudoaneurysm.

    Science.gov (United States)

    Nguyen, Vien X; Nguyen, Ba D

    2014-05-01

    Acute aortic syndromes, encompassing intramural hematoma, penetrating ulcer, and pseudoaneurysm, are best demonstrated by angiographic CT and magnetic resonance imaging. These imaging modalities provide an accurate evaluation and allow timely therapies of these frequently symptomatic lesions, thus reducing their morbidity and mortality. The inflammatory pathogenesis of these acute aortic syndromes may exhibit positive PET findings predictive of prognosis and outcomes of these vascular events. The authors present a case of PET/CT imaging showing asymptomatic intramural hematomas with penetrating ulcer and saccular pseudoaneurysm of the proximal abdominal aorta.

  20. Evaluation of five image registration tools for abdominal CT: pitfalls and opportunities with soft anatomy

    Science.gov (United States)

    Lee, Christopher P.; Xu, Zhoubing; Burke, Ryan P.; Baucom, Rebeccah; Poulose, Benjamin K.; Abramson, Richard G.; Landman, Bennett A.

    2015-03-01

    Image registration has become an essential image processing technique to compare data across time and individuals. With the successes in volumetric brain registration, general-purpose software tools are beginning to be applied to abdominal computed tomography (CT) scans. Herein, we evaluate five current tools for registering clinically acquired abdominal CT scans. Twelve abdominal organs were labeled on a set of 20 atlases to enable assessment of correspondence. The 20 atlases were pairwise registered based on only intensity information with five registration tools (affine IRTK, FNIRT, Non-Rigid IRTK, NiftyReg, and ANTs). Following the brain literature, the Dice similarity coefficient (DSC), mean surface distance, and Hausdorff distance were calculated on the registered organs individually. However, interpretation was confounded due to a significant proportion of outliers. Examining the retrospectively selected top 1 and 5 atlases for each target revealed that there was a substantive performance difference between methods. To further our understanding, we constructed majority vote segmentation with the top 5 DSC values for each organ and target. The results illustrated a median improvement of 85% in DSC between the raw results and majority vote. These experiments show that some images may be well registered to some targets using the available software tools, but there is significant room for improvement and reveals the need for innovation and research in the field of registration in abdominal CTs. If image registration is to be used for local interpretation of abdominal CT, great care must be taken to account for outliers (e.g., atlas selection in statistical fusion).

  1. Lung Cancer Screening with Low Dose CT

    Science.gov (United States)

    Caroline, Chiles

    2014-01-01

    SUMMARY The announcement of the results of the NLST, showing a 20% reduction in lung-cancer specific mortality with LDCT screening in a high risk population, marked a turning point in lung cancer screening. This was the first time that a randomized controlled trial had shown a mortality reduction with an imaging modality aimed at early detection of lung cancer. Current guidelines endorse LDCT screening for smokers and former smokers ages 55 to 74, with at least a 30 pack year smoking history. Adherence to published algorithms for nodule follow-up is strongly encouraged. Future directions for screening research include risk stratification for selection of the screening population, and improvements in the diagnostic follow-up for indeterminate pulmonary nodules. As with screening for other malignancies, screening for lung cancer with LDCT has revealed that there are indolent lung cancers which may not be fatal. More research is necessary if we are to maximize the risk-benefit ratio in lung cancer screening. PMID:24267709

  2. Postoperative findings following the Whipple procedure: determination of prevalence and morphologic abdominal CT features

    Energy Technology Data Exchange (ETDEWEB)

    Mortele, K.J.; Lemmerling, M.; Bock, G. de; Kunnen, M. [Department of Radiology, University Hospital Gent (Belgium); Hemptinne, B. de [Department of Digestive Surgery, University Hospital Gent (Belgium); Vos, M. de [Department of Gastroenterology, University Hospital Gent (Belgium)

    2000-01-01

    This study was conducted to determine characteristic CT findings following the Whipple procedure and to evaluate the usefulness of CT in predicting tumor recurrence. Eighty-four postoperative abdominal CT scans and medical records of 43 patients were retrospectively reviewed. Perioperative histopathologic examinations revealed malignancy in 32 patients (74.4 %). Time interval between surgery and CT varied from 13 days to 6 years and 7 months. Common postoperative findings were unopacified anastomotic bowel loops in the porta hepatis (n = 69 scans), perivascular cuffing (n = 42 scans), pneumobilia (n = 40 scans), dilated intrahepatic bile ducts (n = 22 scans), reactive lymphadenopathy (n = 21 scans), and transient fluid collections (n = 20 scans). Postoperative complications were detected on 17 CT scans (20.2 %): generalized ascites (n = 8 patients), deep abscesses (n = 3 patients), wound abscess (n = 1 patient), pancreatitis (n = 1 patient), and pseudomembranous colitis (n = 1 patient). Tumor recurrence appeared in 15 patients (46.8 %) after a mean postoperative period of 11 months (1 month to 3 years): local (9 of 15), regional lymph nodes (9 of 15), and liver metastasis (8 of 15). Detection of generalized ascites more than 30 days after surgery was associated with tumor recurrence in 6 of 6 patients (100 %). Diffuse ascites (> 30 days after surgery) behaved as an early predictive sign of tumor recurrence. In our series CT accuracy for detecting recurrent tumor with CT was 93.5 %. No predilection site for disease recurrence could be determined. (orig.)

  3. A prospective evaluation of CT features predictive of intra-abdominal hypertension and abdominal compartment syndrome in critically ill surgical patients

    Energy Technology Data Exchange (ETDEWEB)

    Al-Bahrani, A.Z. [Department of Surgery, Manchester Royal Infirmary, Manchester (United Kingdom); Abid, G.H. [Department of Surgery, Manchester Royal Infirmary, Manchester (United Kingdom); Sahgal, E. [Department of Surgery, Manchester Royal Infirmary, Manchester (United Kingdom); O' Shea, S. [Department of Radiology, Manchester Royal Infirmary, Manchester (United Kingdom); Lee, S. [Department of Surgery, Manchester Royal Infirmary, Manchester (United Kingdom); Ammori, B.J. [Department of Surgery, Manchester Royal Infirmary, Manchester (United Kingdom)]. E-mail: bammori@btinternet.com

    2007-07-15

    Aim: The aim of this study was to validate the computed tomography (CT) features of intra-abdominal hypertension (IAH) by relating them to the clinical measurement of intra-abdominal pressure (IAP) in critically ill surgical patients. Materials and methods: The intra-vesical pressure was measured to reflect IAP in 24 critically ill patients. CT examinations obtained within 24 h of IAP measurement were reviewed and scored independently by two consultant radiologists. Each CT examination was scored for the seven proposed features of IAH. Images obtained during the presence of IAH were compared with those obtained in the absence of IAH. Results: Forty-eight abdominal CT examinations were evaluated, of which 18 (38%) were obtained in the presence of IAH, whereas eight (17%) were obtained in the presence of abdominal compartment syndrome (ACS). At CT, the round belly sign (RBS) and bowel wall thickening with enhancement (BWTE) were significantly more frequently detected during the presence of IAH than when the IAP was less than 12 mmHg (78 versus 20% of examinations, p < 0.001 and 39 versus 3% of examinations, p = 0.003, respectively), but only BWTE was significantly associated with the presence of ACS (40 versus 11% of examinations, p = 0.047). Conclusion: The presence of RBS and BWTE on CT images of critically ill surgical patients should alert clinicians to the possibility of presence of IAH and ACS, and prompt measurement of the IAP and consideration of suitable interventions.

  4. A brief report of basic science: the effects of preincisional low-dose ketamine on natural killer cell activity in male Fischer 344 rats after intra-abdominal surgery.

    Science.gov (United States)

    Estes, Savannah; Dinh, Tim; Garrett, Normalynn

    2009-01-01

    Although the first line of defense in cancer treatment often is surgery, studies suggest that postoperative pain and anesthetic drugs suppress the activity of cells that lyse metastatic cells, that is, natural killer cells. We assessed the affect of low-dose ketamine on natural killer cell activity. The findings are presented in this brief report.

  5. Clinical Study of Low-dose Spiral CT Angiography Scan Inlfated Stomach Gastric%螺旋CT低剂量胃充气造影扫描在胃癌的临床研究

    Institute of Scientific and Technical Information of China (English)

    罗锦文; 邓义; 刘玉新; 杨壁然; 刘燕

    2015-01-01

    目的:分析螺旋CT低剂量胃充气造影扫描在胃癌诊断中的效果。方法90例经胃镜检查拟诊胃癌并需要做螺旋CT检查患者,按就诊顺序随机分成3组,每组30例。A组参照组采用固定毫安法,120kv,150mAs;B、C组低剂量组均采用智能毫安调制法,管电压120KV,使用智能毫安法,噪声指数SD值分别为12、15,造影剂均使用碘海醇(300mgI/ml),1.2ml/kg,扫描后将原始薄层图像在东芝16排CT Vitrea工作站上进行后处理,将轴位图像和重组图像传送至NFPACS上,分别记录每组病例的CT容积剂量指数(CTDIvol),评价图像质量。结果 A、B扫描图像质量的差异不具有统计学意义(P>0.05),A、B组剂量加权指数降低率的差异具有统计学意义,A、C组间扫描图像质量、剂量加权指数降低率的差异具有统计学意义(P<0.05),B、C组间扫描图像质量/剂量加权指数降低率的差异具有统计学意义。结论 B、C组使用智能毫安调制法可以有效降低辐射剂量值,B组扫描条件可以作为常规扫描方案,以降低辐射剂量;C组图像质量显示欠佳,容易造成漏诊,该方案不推荐应用于胃部肿瘤扫描;在不影响诊断准确性的前提下,在一定范围内减少辐射剂量可获得与常规剂量相同的影像信息和图像质量,应该在临床中进行推广和应用,更好的对胃癌进行诊断,力求减低病人的辐射量,提高低剂量筛查早期胃癌的诊断率。%Objective to analyze the value on the low-dose spiral CT scan of inflated stomach in the diagnosis of gastric cancer.Methods 90 cases of stomach cancer diagnosed by endoscopy who need to do spiral CT san examination were divided into three groups averagely in order. A group, the reference group was taking the way of a fixed tube mA, 120 KV, 150 mAs; B,C Group,as the low-dose group were taking the smart mA modulation method, the tube voltage of 120 KV, using

  6. Arterial enhancement at abdominal CT angiography: Low- versus high-osmolality contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Rouviere, O.; Berger, P.; Pangaud, C.; Lyonnet, D. [Hopital E. Herriot, Lyon (France). Dept. of Vascular and Genitourinary Radiology; Ecochard, R. [Hospices Civils de Lyon (France). Dept of Biostatistics; Fontaine, B. [Laboratoire Guerbet, Roissy (France)

    2000-09-01

    Purpose: To evaluate the effects of contrast media pharmokinetic differences on aortic enhancement at abdominal CT angiography and to determine whether these effects are of clinical relevance. Material and Methods: Two hundred and twelve patients referred for abdominal CT angiography were included in the study. All abdominal CT angiograms were performed with the same parameters (collimation 3 mm, pitch ratio 1.7, scan delay 30 s) after i.v. injection of 120 ml of contrast medium at 3 ml/s. After randomization, patients received either iobitridol 300 (low-osmolar, 300 mg I/ml), iobitridol 350 (low-osmolar, 350 mg I/ml) or ioxithalamate 350 (high-osmolar, 350 mg I/ml). The time attenuation curves obtained with the three contrast media were compared. Results: The time attenuation curve obtained with ioxithalamate 350 was not parallel to those obtained with iobitridol 300 and iobitridol 350. Mean peak enhancements obtained with iobitridol 350 and ioxithalamate 350 were not significantly different but iobitridol 350 provided higher mean peak enhancement than iobitridol 300. Mean delays of the peak enhancements were the same with the three contrast media. After peak enhancement, the decrease of aortic opacification under a selected threshold of 200 HU was significantly slower with iobitridol 350 than with iobitridol 300 and ioxithalamate 350, whereas iobitridol 300 and ioxithalamate 350 showed no significant differences. Conclusion: For a given iodine concentration, low-osmolality contrast media provide longer aortic opacification and may be recommended for CT angiography when long acquisition times are needed.

  7. Low-dose 16-slice spiral CT thoracic angiography using Z-axis modulation%16层CT胸部血管成像Z轴调制低剂量研究

    Institute of Scientific and Technical Information of China (English)

    李惠民; 于红; 肖湘生; 虞崚崴

    2011-01-01

    Objective To explore the feasibility of low dose in MSCT thoracic angiography using Z-axis modulation. Methods The consecutive 60 patients were averagely divided into 3 groups and underwent thoracic angiography with a Toshiba Aquilion 16 scanner. The whole chest acquisition was commenced in automatic exposure control with Z-axis modulation 20-25 seconds after the contrast material was administered at the rate of 3.5-4. 0 ml/s. With the noise index (SD) as the variable, three study groups were classified as A (SD = 12) , B (SD = 15 ), and C (SD = 18 ). The mAs value per slice and the number of slices were recorded. The noises and artifacts of the axial images and the acceptability of CT angiogram were evaluated. The difference among the groups was compared by using ANOVA or nonparametric Kruskal-Wallis test. The threshold of the P value was 0. 05. Results The mean mAs value (46. 4 ± 15.6) mAs in group A was the highest but the SD value (21.6 ±7.7) was the lowest. The mean mAs value ( 37. 0 ± 13.5 ) and the SD value ( 24. 0 t 5.4 ) in group B were the mediate. The mean mAs value ( 20. 7 ±6.3) mAs in group C was the lowe(s)t but the SD value ( 30. 7 ± 6.9) was the highest ( H = 31. 390, P =0. 000). The middle slice images in all patients had the smallest mAs (40. 9,31.3,17. 1 for group A,B,C,respectively; F =9. 578, H =22. 230, F =21. 180,P =0. 000) and SD values( 16. 3, 20. 0,25.4 for group A,B,C, respectively; H = 28. 982, H = 20. 824, H = 24. 396, P = 0. 000). The acceptability of CT angiogram in all patients was excellent. The CT value of descending aorta in group A, B, and C was ( 335 ± 85 ) HU,(334 ±56)HU, and (427 ± 63 )HU, respectively. Conclusion Low dose in MSCT thoracic angiography using Z-axis modulation is feasible. We can use low dose (20 mAs, etc. ) for CT angiography when the contrast is significant.%目的 探讨16层CT胸部增强血管成像中Z轴调制合理低剂量的可行性.方法 连续60例患者依序分为3组,每组20例,采用16

  8. Abdominal CT Does Not Improve Outcome for Children with Suspected Acute Appendicitis

    Directory of Open Access Journals (Sweden)

    Danielle I. Miano

    2015-12-01

    Full Text Available Introduction: Acute appendicitis in children is a clinical diagnosis, which often requires preoperative confirmation with either ultrasound (US or computed tomography (CT studies. CTs expose children to radiation, which may increase the lifetime risk of developing malignancy. US in the pediatric population with appropriate clinical follow up and serial exam may be an effective diagnostic modality for many children without incurring the risk of radiation. The objective of the study was to compare the rate of appendiceal rupture and negative appendectomies between children with and without abdominal CTs; and to evaluate the same outcomes for children with and without USs to determine if there were any associations between imaging modalities and outcomes. Methods: We conducted a retrospective chart review including emergency department (ED and inpatient records from 1/1/2009–2/31/2010 and included patients with suspected acute appendicitis. Results: 1,493 children, aged less than one year to 20 years, were identified in the ED with suspected appendicitis. These patients presented with abdominal pain who had either a surgical consult or an abdominal imaging study to evaluate for appendicitis, or were transferred from an outside hospital or primary care physician office with the stated suspicion of acute appendicitis. Of these patients, 739 were sent home following evaluation in the ED and did not return within the subsequent two weeks and were therefore presumed not to have appendicitis. A total of 754 were admitted and form the study population, of which 20% received a CT, 53% US, and 8% received both. Of these 57%, 95% CI [53.5,60.5] had pathology-proven appendicitis. Appendicitis rates were similar for children with a CT (57%, 95% CI [49.6,64.4] compared to those without (57%, 95% CI [52.9,61.0]. Children with perforation were similar between those with a CT (18%, 95% CI [12.3,23.7] and those without (13%, 95% CI [10.3,15.7]. The proportion of

  9. Screenings of lung cancer with low dose spiral CT: results of a three year pilot study and design of the randomised controlled trial Italung-CT; Screening della neoplasia polmonare con TC spirale a bassa dose: risultati di uno studio pilota triennale e disegno dello studio clinico randomizzato Italung-CT

    Energy Technology Data Exchange (ETDEWEB)

    Picozzi, Giulia [Firenze Univ., Firenze (Italy). Radiodiagnostica I-Dipartimento di Fisiopatologia Clinica; Paci, Enrico [Azienda Ospedaliera Universitaria di Careggi, Firenze (Italy). Unita' di Epidemiologia Clinica e Descrittiva Centro per lo Studio e la Prevenzione Oncologica; Lopes Pegna, Andrea [Azienda Ospedaliera Universitaria di Careggi, Firenze (Italy). U.O. Pneumologia] [and others

    2005-02-01

    Purpose: To report the results of a three-year observational pilot study of lung cancer screening with low dose computed tomography (CT) and to present the study design of a randomised clinical trial named as Italung CT. Materials and methods: Sixty (47 males and 13 females, mean age 64{+-}4.5 years) heavy smokers (at least 20 packs-year) underwent three low-dose spiral CT screening tests one year apart on a single slice or multislice CT scanner. Indeterminate nodules were managed according to the recommendations of the Early Lung Cancer Action Project. Results: Indeterminate nodules were observed in 33 (55%) of the subjects (60% at the baseline screening test, 24% at the first annual test and 16% at the second annual test). The size of the largest indeterminate nodule was <5mm in diameter in 20 subjects. 10 of whom showed the nodule at the baseline test. Forty-five subjects (75%) completed the first annual test and 42 (70%) the second annual test. One (1.6%) prevalent lung cancer (adenosquamous carcinoma) and one (2.2%) incident lung cancer (small cell cancer at the first annual examination) were observed, as well as pulmonary localisation of Hodgkin's lymphoma (at the second annual test). In addition, one subject underwent lung surgery for a chondromatous hamartoma. Conclusions: The results of the pilot study are substantially in line with those of other observational studies of greater sample size. This justifies optimism about the reliability of the results in the screened arm of the Italung Ct trial which hast just began. [Italian] Scopo: Riportare i risultati di uno studio pilota osservazionale di screening della neoplasia polmonare con TC a bassa dose della durata di tre anni e presentare il disegno dello studio clinico randomizzato Italung-CT. Materiale e metodi: Sessanta (47 uomini e 13 donne, eta' media 64{+-}4,5 anni) forti fumatori (almeno 20 pacchetti/anno) sono stati sottoposti ad un esame basale e a due controlli annuali con TC single o

  10. Patient-size-dependent radiation dose optimisation technique for abdominal CT examinations.

    Science.gov (United States)

    Ngaile, J E; Msaki, P; Kazema, R

    2012-01-01

    Since patient doses from computed tomography (CT) are relatively high, risk-benefit analysis requires dose to patients and image quality be optimised. The aim of this study was to develop a patient-dependent optimisation technique that uses patient diameter to select a combination of CT scanning parameters that minimise dose delivered to patients undergoing abdominal CT examinations. The study was performed using cylindrical phantoms of diameters ranging from 16 to 40 cm in order to establish the relationship between image degradation, CT scanning techniques, patient dose and patient size from two CT scanners. These relationships were established by scanning the phantoms using standard scanning technique followed by selected combinations of scanning parameters. The image noises through phantom images were determined using region of interest software available in both scanners. The energy depositions to the X-ray detector through phantoms were determined from measurements of CT dose index in air corrected for attenuation of the phantom materials. The results demonstrate that exposure settings (milliampere seconds) could be reduced by up to 82 % for smaller phantom relative to standard milliampere seconds, while detector signal could be reduced by up to 93 % for smaller phantom relative to energy depositions required when scanned using standard scanning protocols. It was further revealed that the use of the object-specific scanning parameters on studies performed with phantom of different diameters could reduce the incident radiation to small size object by up to 86 % to obtain the same image quality required for standard adult object. In view of the earlier mentioned fact, substantial dose saving from small-sized adults and children patients undergoing abdomen CT examinations could be achieved through optimal adjustment of CT scanning technique based on the patient transverse diameter.

  11. Multidetector computed tomography in abdominal emergencies; Multidetektor-CT bei abdominellen Notfaellen

    Energy Technology Data Exchange (ETDEWEB)

    Zorger, N.; Schreyer, A.G. [Universitaetsklinikum Regensburg (Germany). Institut fuer Roentgendiagnostik

    2009-06-15

    Abdominal emergencies encompass traumatic events in the region of the abdomen as well as the clinical term acute abdomen. Multidetector CT (MDCT) represents one of the most important imaging modalities for detection and correct diagnosis in such abdominal emergencies. Based on the acquired data MDCT allows a stable imaging of the abdomen in an extremely short time even in critically ill patients. Multiplanar reconstructions can be created based on the high resolution data allowing an impressive visualization of the pathology. In this review article the most important abdominal pathologies of the abdomen diagnosed by MDCT are presented with special emphasis on the liver, bile ducts, spleen and kidneys as well as the gastro-intestinal tract. Additionally, MDCT imaging of the individual organ regions will be dealt with in detail. (orig.) [German] Abdominelle Notfaelle beinhalten sowohl traumatische Ereignisse im Bereich des Bauchraums als auch den klinischen Begriff des ''akuten Abdomens''. Die Darstellung solcher Notfaelle mittels Multidetektor-Computertomographie (MDCT) ist eine leistungsfaehige Methode zur Detektion und richtigen Diagnosefindung der abdominellen Notfaelle. Die MDCT erlaubt eine stabile Bildgebung des Abdomens in extrem kurzer Zeit bei schwerkranken Patienten und zudem multiplanare Rekonstruktionen, basierend auf den akquirierten Rohdatensaetzen mit der Moeglichkeit, zusaetzlich Befunde anschaulicher zu visualisieren. In diesem Uebersichtsartikel werden die MDCT-Charakteristika verschiedener abdomineller Notfaelle der wichtigsten Organregionen des Abdomens, wie der Leber und der Gallenwege, des Pankreas, der Milz und der Niere sowie des Gastrointestinaltrakts erlaeutert. Dabei wird speziell auf die Multidetektor-CT-Technik der einzelnen Organregionen eingegangen. (orig.)

  12. 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.)

  13. 3D segmentation of abdominal aorta from CT-scan and MR images.

    Science.gov (United States)

    Duquette, Anthony Adam; Jodoin, Pierre-Marc; Bouchot, Olivier; Lalande, Alain

    2012-06-01

    We designed a generic method for segmenting the aneurismal sac of an abdominal aortic aneurysm (AAA) both from multi-slice MR and CT-scan examinations. It is a semi-automatic method requiring little human intervention and based on graph cut theory to segment the lumen interface and the aortic wall of AAAs. Our segmentation method works independently on MRI and CT-scan volumes and has been tested on a 44 patient dataset and 10 synthetic images. Segmentation and maximum diameter estimation were compared to manual tracing from 4 experts. An inter-observer study was performed in order to measure the variability range of a human observer. Based on three metrics (the maximum aortic diameter, the volume overlap and the Hausdorff distance) the variability of the results obtained by our method is shown to be similar to that of a human operator, both for the lumen interface and the aortic wall. As will be shown, the average distance obtained with our method is less than one standard deviation away from each expert, both for healthy subjects and for patients with AAA. Our semi-automatic method provides reliable contours of the abdominal aorta from CT-scan or MRI, allowing rapid and reproducible evaluations of AAA.

  14. Dose reduction at abdominal CT imaging: reduced tension (kV) or reduced intensity (mAs)?; Diminuer la dose en tomodensitometrie abdominale: baisser la tension (kV) ou la charge (mAs)?

    Energy Technology Data Exchange (ETDEWEB)

    Dion, A.M.; Helie, O.; Cordoliani, Y.S. [Hopital d' Instruction des Armees du Val-de-Grace, Service d' Imagerie, 75 - Paris (France); Berger, F.; Ott, D.; Spiegel, A. [Hopital d' Instruction des Armees Begin, Service de Medecine des Collectivites et d' Etudes Statistiques, 94 - Saint-Mande (France)

    2004-04-01

    Purpose. To compare low-dose protocols using either reduction of the tension (kV) or reduction of the intensity (mAs) at abdominal CT imaging, with reference to image quality. Materials and Methods. Fifty adult patients, weighing less than 55 kg, were prospectively included among patients referred for abdominal CT examination when the protocol required a non-contrast study. The images obtained with the standard protocol (120 kV, 200 mAs) were compared to 4 additional test images, two obtained with low intensity (120 kV, 100 mAs) and two obtained with low tension (100 kV, 200 mAs). Two senior radiologists blindly reviewed all images using both subjective (itemized list) and objective criteria (measure of standard deviation for density measurements obtained of the liver,parenchyma). Results. The image quality of the low kV protocol was better than the image quality of the low mAs protocol for both subjective and objective criteria. Conclusion. For abdominal CT imaging of standard to thin adult patients or children, dose reduction using a low kV-protocol may be an alternative to a protocol using a, low intensity. This can easily be implemented and can be used in conjunction with a dose reducing software. (author)

  15. 基于偏微分方程的低剂量CT投影降噪算法%DENOISING ALGORITHM FOR LOW-DOSE CT PROJECTION BASED ON PARTIAL DIFFERENTIAL EQUATION

    Institute of Scientific and Technical Information of China (English)

    唐瑜; 崔学英; 张权; 刘祎; 桂志国

    2014-01-01

    Because of using lower X-ray dose,the harm of radiation in low-dose CT image on the human body is greatly reduced.But the problem it brings out is that the projection data are polluted seriously by the noise,thus leads to the reductions in quality of the reconstructed image.In view of the above problems,based on partial differential equations we present an improved projectiond domain denoising algorithm. On the basis of the anisotropic diffusion equation,the algorithm can effectively reflect the feature of local characteristics of the image by using the local entropy to control the degree of diffusion.Experimental results show that the new algorithm better preserves the detail and edge information of the reconstructed image while increasing the SNR of reconstructed image.%低剂量 CT 图像由于采用了较低的 X 射线放射剂量,大大降低了辐射对人体的危害,但由此带来的问题是投影数据受噪声污染严重,从而导致了重建图像质量的降低。针对上述问题,在基于偏微分方程的基础上,提出一种改进的投影域降噪算法。该算法在各向异性扩散方程的基础上,利用局部熵可以有效地反映图像局部特征的特点,来控制扩散的程度。实验结果表明,新的算法在提高重建图像信噪比的同时更好地保持了图像的细节和边缘信息。

  16. Spectrum of abdominal pathologies detected with CT in long term dialysis patients

    Energy Technology Data Exchange (ETDEWEB)

    Ulu, Esra Meltem Kayahan [Baskent University Faculty of Medicine, Department of Radiology, Fevzi Cakmak cad. No.: 45, Bahcelievler/Ankara (Turkey)], E-mail: emkayahanulu@yahoo.com; Tarhan, N. Cagla [Baskent University Faculty of Medicine, Department of Radiology, Fevzi Cakmak cad. No.: 45, Bahcelievler/Ankara (Turkey); Hocaoglu, Elif [Bakirkoy Dr Sadi Konuk Training and Research Hospital, Department of Radiology, Zuhurat Baba mah, Bakirkoy/Istanbul (Turkey); Akman, Beril [Department of Nephrology, Fevzi Cakmak cad. No.: 45, Bahcelievler/Ankara (Turkey); Basaran, Ceyla; Donmez, Fuldem Yildirim; Niron, Emin Alp [Baskent University Faculty of Medicine, Department of Radiology, Fevzi Cakmak cad. No.: 45, Bahcelievler/Ankara (Turkey)

    2009-11-15

    As a consequence of the expanded use of long term hemodialysis and continuous ambulatory peritoneal dialysis (CAPD) treatments and extended life spans, complications of end-stage renal disease and dialysis treatments are being encountered with increasing frequency in these patients. Computed tomography can accurately depict many of the potential complications of end-stage renal disease on dialysis. This article presents the abdominal CT findings of 429 end-stage renal disease patients who are on either hemodialysis or continuous ambulatory peritoneal dialysis treatment.

  17. Spleen Segmentation and Assessment in CT Images for Traumatic Abdominal Injuries.

    Science.gov (United States)

    Reza Soroushmehr, S M; Davuluri, Pavani; Molaei, Somayeh; Hargraves, Rosalyn Hobson; Tang, Yang; Cockrell, Charles H; Ward, Kevin; Najarian, Kayvan

    2015-09-01

    Spleen segmentation is especially challenging as the majority of solid organs in the abdomen region have similar gray level range. Physician analysis of computed tomography (CT) images to assess abdominal trauma could be very time consuming and hence, automating this process can reduce time to treatment. The proposed method presented in this paper is a fully automated and knowledge based technique that employs anatomical information to accurately segment the spleen in CT images. The spleen detection procedure is proposed to locate the spleen in both healthy and injured cases. In the presence of hemorrhage and laceration, the edge merging technique is used. The accuracy of the method is measured by some criteria such as mis-segmented area, accuracy, specificity and sensitivity. The results show that the proposed spleen segmentation method performs well and outperforms other methods.

  18. Abdominal CT predictors of fibrosis in patients with chronic pancreatitis undergoing surgery

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Amitasha; Afghani, Elham [Johns Hopkins Medical Institutions, Division of Gastroenterology, Baltimore, MD (United States); Singh, Vikesh K. [Johns Hopkins Medical Institutions, Division of Gastroenterology, Baltimore, MD (United States); Johns Hopkins Medical Institutions, Pancreatitis Center, Baltimore, MD (United States); Cruise, Michael; Matsukuma, Karen [Johns Hopkins Medical Institutions, Department of Pathology, Baltimore, MD (United States); Ali, Sumera; Raman, Siva P.; Fishman, Elliot K. [Johns Hopkins Medical Institutions, The Russel H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Andersen, Dana K. [National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD (United States); Makary, Martin A. [Johns Hopkins Medical Institutions, Department of Surgery, Baltimore, MD (United States); Johns Hopkins Medical Institutions, Pancreatitis Center, Baltimore, MD (United States); Zaheer, Atif [Johns Hopkins Medical Institutions, The Russel H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Johns Hopkins Medical Institutions, Pancreatitis Center, Baltimore, MD (United States); Johns Hopkins Medical Institutions, Baltimore, MD (United States)

    2015-05-01

    To determine which abdominal CT findings predict severe fibrosis and post-operative pain relief in chronic pancreatitis (CP). Pre-operative abdominal CTs of 66 patients (mean age 52 ± 12 years, 53 % males) with painful CP who underwent the Whipple procedure (n = 32), Frey procedure (n = 32) or pancreatic head biopsy (n = 2), between 1/2003-3/2014, were evaluated. CT was evaluated for parenchymal calcifications, intraductal calculi, main pancreatic duct dilation (>5 mm), main pancreatic duct stricture, and abnormal side branch(es). The surgical histopathology was graded for fibrosis. CT findings were evaluated as predictors of severe fibrosis and post-operative pain relief using regression and area under receiver operating curve (AUC) analysis. Thirty-eight (58 %) patients had severe fibrosis. Parenchymal calcification(s) were an independent predictor of severe fibrosis (p = 0.03), and post-operative pain relief over a mean follow-up of 1-year (p = 0.04). Presence of >10 parenchymal calcifications had higher predictive accuracy for severe fibrosis than 1-10 parenchymal calcification(s) (AUC 0.88 vs. 0.59, p = 0.003). The predictive accuracy of >10 versus 1-10 parenchymal calcifications increased after adjusting for all other CT findings (AUC 0.89 vs. 0.63, p = 0.01). Parenchymal calcification(s) independently predict severe fibrosis and are significantly associated with post-operative pain relief in CP. The presence of >10 parenchymal calcifications is a better predictor of severe fibrosis than 1-10 parenchymal calcification(s). (orig.)

  19. Abdominal and pelvic CT: is positive enteric contrast still necessary? Results of a retrospective observational study

    Energy Technology Data Exchange (ETDEWEB)

    Kammerer, S.; Hoeink, A.J.; Wessling, J.; Schuelke, C.; Heindel, W.; Buerke, B. [University Hospital Muenster, Department of Clinical Radiology, Muenster (Germany); Heinzow, H. [University Hospital Muenster, Department of Gastroenterology and Metabolic Diseases, Muenster (Germany); Koch, R. [University Muenster, Institute of Biostatistics and Clinical Research, Muenster (Germany)

    2014-10-15

    Evaluation of diagnostic accuracy of abdominal CT depending on the type of enteric contrast agent. Multislice CTs of 2,008 patients with different types of oral preparation (positive with barium, n = 576; neutral with water, n = 716; and no enteric contrast, n = 716) were retrospectively evaluated by two radiologists including delineation of intestinal segments and influence on diagnosis and diagnostic reliability exerted by the enteric contrast, using a three-point scale. Furthermore, diagnostic reliability of the delineation of selected enteric pathologies was noted. CT data were assigned into groups: oncology, inflammation, vascular, pathology, trauma and gastrointestinal pathology. Delineation of the bowel was clearly practicable across all segments irrespective of the type of enteric contrast, though a slight impairment was observed without enteric contrast. Although delineation of intestinal pathologies was mostly classified ''clearly delimitable'' more difficulties occurred without oral contrast (neutral/positive/no contrast, 0.8 %/3.8 %/6.5 %). Compared to examinations without enteric contrast, there was a significant improvement in diagnosis that was even increased regarding the reader's diagnostic reliability. Positive opacification impaired detection of mucosal enhancement or intestinal bleeding. Water can replace positive enteric contrast agents in abdominal CTs. However, selected clinical questions require individual enteric contrast preparations. Pathology detection is noticeably impaired without any enteric contrast. circle Neutral oral contrast ensures an equivalent delineation of the bowel. (orig.)

  20. Efficacy of 'fine' focal spot imaging in CT abdominal angiography

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Lawrence Chia Wei; Devapalasundaram, Ashwini; Ardley, Nicholas [Monash Health, Department of Diagnostic Imaging, Clayton, Victoria (Australia); Lau, Kenneth K. [Monash Health, Department of Diagnostic Imaging, Clayton, Victoria (Australia); Monash University, Department of Medicine, Faculty of Medicine, Nursing, and Health Sciences, Victoria (Australia); Buchan, Kevin [Phillips Healthcare, Clinical Science, PO Box 312, Mont Albert, Victoria (Australia); Huynh, Minh [RMIT University, School of Mathematical and Geospatial Sciences, Victoria (Australia)

    2014-12-15

    To assess the efficacy of fine focal spot imaging in calcification beam-hardening artefact reduction and vessel clarity on CT abdominal angiography (CTAA). Adult patients of any age and gender who presented for CTAA were included. Thirty-nine patients were examined with a standard focal spot size (SFSS) of 1 x 1 mm in the first 3 months while 31 consecutive patients were examined with a fine focal spot size (FFSS) of 1 x 0.5 mm in the following 3 months. Vessel clarity and calcification beam-hardening artefacts of the abdominal aorta, celiac axis, superior mesenteric artery, inferior mesenteric artery, renal arteries, and iliac arteries were assessed using a 5-point grading scale by two blinded radiologists randomly. Cohen's Kappa test indicated that on average, there was substantial agreement among reviewers for vessel wall clarity and calcification artefact grading. Mann-Whitney test showed that there was a significant difference between the two groups, with FFSS performing significantly better for vessel clarity (U, 6481.50; p < 0.001; r, 0.73) and calcification artefact reduction (U, 1916; p < 0.001; r, 0.77). Fine focus CT angiography produces images with better vessel wall clarity and less vessel calcification beam-hardening artefact. (orig.)

  1. Pain Outcomes in Patients Undergoing CT-Guided Celiac Plexus Neurolysis for Intractable Abdominal Visceral Pain.

    Science.gov (United States)

    Edelstein, Mark R; Gabriel, Ryan T; Elbich, Jeffrey D; Wolfe, Luke G; Sydnor, Malcolm K

    2017-03-01

    The purpose of this study was to assess outcomes in patients who have undergone celiac plexus neurolysis (CPN) as treatment for refractory abdominal visceral pain at a tertiary care medical center. This study involved retrospective analysis of all patients who had undergone computed tomography (CT)-guided CPN over a 7-year period, as identified in the medical record. Cases were categorized into 1 of 3 groups-group 1: patients getting at least moderate improvement in pain but with improvements subsiding within 2 days; group 2: patients with some sustained pain relief but still requiring heavy doses of narcotics; group 3: patients with major or complete sustained reduction in pain where the narcotic dose was able to be reduced. One hundred thirty-eight cases were identified, 51 of which had no or insufficient follow-up, leaving 87 cases for analysis. Of the 87 cases, 31 (36%) were categorized as group 1, 21 (24%) as group 2, and 35 (40%) as group 3. There were no statistical differences in outcomes based on patient age, gender, time since diagnosis, or type of cancer. Documented postoperative complications were diarrhea (11 cases) and 1 case each of obtundation, hypotension, and presyncopal event. We conclude that patients undergoing CT-guided CPN for abdominal visceral pain achieve moderate or major short-term pain relief in a majority of cases. The procedure is safe with minimal complications.

  2. Towards the clinical implementation of iterative low-dose cone-beam CT reconstruction in image-guided radiation therapy: Cone/ring artifact correction and multiple GPU implementation

    Science.gov (United States)

    Yan, Hao; Wang, Xiaoyu; Shi, Feng; Bai, Ti; Folkerts, Michael; Cervino, Laura; Jiang, Steve B.; Jia, Xun

    2014-01-01

    , an overall 3.1 × speedup factor has been achieved with four GPU cards compared to a single GPU-based reconstruction. The total computation time is ∼30 s for typical clinical cases. Conclusions: The authors have developed a low-dose CBCT IR system for IGRT. By incorporating data consistency-based weighting factors in the IR model, cone/ring artifacts can be mitigated. A boost in computational efficiency is achieved by multi-GPU implementation. PMID:25370645

  3. Dictionary learning based denoising of low-dose X-ray CT image%基于字典学习的低剂量X-ray CT图像去噪

    Institute of Scientific and Technical Information of China (English)

    朱永成; 陈阳; 罗立民; Toumoulin Christine

    2012-01-01

    介绍了一种基于字典学习的去噪方法,并将其应用于降低低剂量CT图像噪声水平的研究.针对体模图像和病人图像,分别选择低剂量CT图像和正常剂量CT图像作为训练样本,采用K-SVD算法,通过迭代学习构建图像字典;然后,结合正交匹配跟踪算法,实现图像稀疏表示,稀疏成分对应于图像的有用信息,其他成分对应于图像噪声;最后,依据图像的稀疏成分重建图像,达到去除噪声的目的.实验结果表明:字典的大小、稀疏表示的约束条件等参数会显著影响所提算法的去噪结果;相比低剂量CT图像,将正常剂量CT图像作为训练样本可以得到更好的去噪结果;在相同的噪声水平下,所提算法与传统图像去噪算法相比可以更好地去除图像噪声,且保留了图像的细节信息.%A dictionary learning based denoising method is introduced to eliminate the noise in low-dose computed-tomography (LDCT) image. Aiming at the phantom and patient images, the &-means singular value decomposition (K-SVD) algorithm is adopted to train image dictionary itera-tively based on LDCT and normal-dose CT (NDCT) images. Then, based on the orthogonal matching pursuit algorithm, the sparse representation decomposes the noise image into sparse component which is related to image information and remains which are regarded as noise. Finally, noises can be suppressed by reconstructing image only with its sparse components. The experimental results show that the performance of the proposed method is strongly affected by the dictionary size and the constraints for sparsity in dictionary training. The better performance can be achieved when training samples are extracted from NDCT image instead of LDCT image. Under the same noise level, compared with the traditional de-noising methods, the proposed method is more effective in suppressing noise and improving the visual effect while maintaining more diagnostic image details.

  4. Pancreas segmentation from 3D abdominal CT images using patient-specific weighted subspatial probabilistic atlases

    Science.gov (United States)

    Karasawa, Kenichi; Oda, Masahiro; Hayashi, Yuichiro; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Rueckert, Daniel; Mori, Kensaku

    2015-03-01

    Abdominal organ segmentations from CT volumes are now widely used in the computer-aided diagnosis and surgery assistance systems. Among abdominal organs, the pancreas is especially difficult to segment because of its large individual differences of the shape and position. In this paper, we propose a new pancreas segmentation method from 3D abdominal CT volumes using patient-specific weighted-subspatial probabilistic atlases. First of all, we perform normalization of organ shapes in training volumes and an input volume. We extract the Volume Of Interest (VOI) of the pancreas from the training volumes and an input volume. We divide each training VOI and input VOI into some cubic regions. We use a nonrigid registration method to register these cubic regions of the training VOI to corresponding regions of the input VOI. Based on the registration results, we calculate similarities between each cubic region of the training VOI and corresponding region of the input VOI. We select cubic regions of training volumes having the top N similarities in each cubic region. We subspatially construct probabilistic atlases weighted by the similarities in each cubic region. After integrating these probabilistic atlases in cubic regions into one, we perform a rough-to-precise segmentation of the pancreas using the atlas. The results of the experiments showed that utilization of the training volumes having the top N similarities in each cubic region led good results of the pancreas segmentation. The Jaccard Index and the average surface distance of the result were 58.9% and 2.04mm on average, respectively.

  5. Efficient Abdominal Segmentation on Clinically Acquired CT with SIMPLE Context Learning.

    Science.gov (United States)

    Xu, Zhoubing; Burke, Ryan P; Lee, Christopher P; Baucom, Rebeccah B; Poulose, Benjamin K; Abramson, Richard G; Landman, Bennett A

    2015-03-20

    Abdominal segmentation on clinically acquired computed tomography (CT) has been a challenging problem given the inter-subject variance of human abdomens and complex 3-D relationships among organs. Multi-atlas segmentation (MAS) provides a potentially robust solution by leveraging label atlases via image registration and statistical fusion. We posit that the efficiency of atlas selection requires further exploration in the context of substantial registration errors. The selective and iterative method for performance level estimation (SIMPLE) method is a MAS technique integrating atlas selection and label fusion that has proven effective for prostate radiotherapy planning. Herein, we revisit atlas selection and fusion techniques for segmenting 12 abdominal structures using clinically acquired CT. Using a re-derived SIMPLE algorithm, we show that performance on multi-organ classification can be improved by accounting for exogenous information through Bayesian priors (so called context learning). These innovations are integrated with the joint label fusion (JLF) approach to reduce the impact of correlated errors among selected atlases for each organ, and a graph cut technique is used to regularize the combined segmentation. In a study of 100 subjects, the proposed method outperformed other comparable MAS approaches, including majority vote, SIMPLE, JLF, and the Wolz locally weighted vote technique. The proposed technique provides consistent improvement over state-of-the-art approaches (median improvement of 7.0% and 16.2% in DSC over JLF and Wolz, respectively) and moves toward efficient segmentation of large-scale clinically acquired CT data for biomarker screening, surgical navigation, and data mining.

  6. Efficient multi-atlas abdominal segmentation on clinically acquired CT with SIMPLE context learning.

    Science.gov (United States)

    Xu, Zhoubing; Burke, Ryan P; Lee, Christopher P; Baucom, Rebeccah B; Poulose, Benjamin K; Abramson, Richard G; Landman, Bennett A

    2015-08-01

    Abdominal segmentation on clinically acquired computed tomography (CT) has been a challenging problem given the inter-subject variance of human abdomens and complex 3-D relationships among organs. Multi-atlas segmentation (MAS) provides a potentially robust solution by leveraging label atlases via image registration and statistical fusion. We posit that the efficiency of atlas selection requires further exploration in the context of substantial registration errors. The selective and iterative method for performance level estimation (SIMPLE) method is a MAS technique integrating atlas selection and label fusion that has proven effective for prostate radiotherapy planning. Herein, we revisit atlas selection and fusion techniques for segmenting 12 abdominal structures using clinically acquired CT. Using a re-derived SIMPLE algorithm, we show that performance on multi-organ classification can be improved by accounting for exogenous information through Bayesian priors (so called context learning). These innovations are integrated with the joint label fusion (JLF) approach to reduce the impact of correlated errors among selected atlases for each organ, and a graph cut technique is used to regularize the combined segmentation. In a study of 100 subjects, the proposed method outperformed other comparable MAS approaches, including majority vote, SIMPLE, JLF, and the Wolz locally weighted vote technique. The proposed technique provides consistent improvement over state-of-the-art approaches (median improvement of 7.0% and 16.2% in DSC over JLF and Wolz, respectively) and moves toward efficient segmentation of large-scale clinically acquired CT data for biomarker screening, surgical navigation, and data mining.

  7. Efficient abdominal segmentation on clinically acquired CT with SIMPLE context learning

    Science.gov (United States)

    Xu, Zhoubing; Burke, Ryan P.; Lee, Christopher P.; Baucom, Rebeccah B.; Poulose, Benjamin K.; Abramson, Richard G.; Landman, Bennett A.

    2015-03-01

    Abdominal segmentation on clinically acquired computed tomography (CT) has been a challenging problem given the inter-subject variance of human abdomens and complex 3-D relationships among organs. Multi-atlas segmentation (MAS) provides a potentially robust solution by leveraging label atlases via image registration and statistical fusion. We posit that the efficiency of atlas selection requires further exploration in the context of substantial registration errors. The selective and iterative method for performance level estimation (SIMPLE) method is a MAS technique integrating atlas selection and label fusion that has proven effective for prostate radiotherapy planning. Herein, we revisit atlas selection and fusion techniques for segmenting 12 abdominal structures using clinically acquired CT. Using a re-derived SIMPLE algorithm, we show that performance on multi-organ classification can be improved by accounting for exogenous information through Bayesian priors (so called context learning). These innovations are integrated with the joint label fusion (JLF) approach to reduce the impact of correlated errors among selected atlases for each organ, and a graph cut technique is used to regularize the combined segmentation. In a study of 100 subjects, the proposed method outperformed other comparable MAS approaches, including majority vote, SIMPLE, JLF, and the Wolz locally weighted vote technique. The proposed technique provides consistent improvement over state-of-the-art approaches (median improvement of 7.0% and 16.2% in DSC over JLF and Wolz, respectively) and moves toward efficient segmentation of large-scale clinically acquired CT data for biomarker screening, surgical navigation, and data mining.

  8. 胸部低剂量CT定量指标与肺气流受限的相关性分析%Correlation between the parameters quantified by chest low-dose CT scan and airflow limitation examined by spirometry

    Institute of Scientific and Technical Information of China (English)

    陈淑靖; 白春学; 顾宇彤; 张静; 余勇夫; 计海婴; 王桂芳; 李丽; 龚颖; 陈刚

    2012-01-01

    目的 探讨胸部低剂量CT(LDCT)定量指标和肺气流受限及其严重程度的相关性,建立初步相关模型.方法 纳入2008年7月至2012年2月在我院同步完成LDCT和肺功能检查的48例40岁以上有吸烟史的患者,对LDCT定量指标和肺功能指标进行相关性分析,并结合年龄、性别等因素建立回归模型.通过绘制受试者工作特征曲线(ROC曲线)确定对气流受限的判断作用最佳的LDCT定量指标.结果 经调整年龄、性别及BMI校正后,EV和El与FEV1、FEV1% pred、FEV1/FVC和TLC% pred呈负相关(P<0.05).但与RV/TLC% pred则无明显相关性(P>0.05);确定最佳回归模型为FEV1/FVC%=94.17+25.31×性别(gender)-0.58×年龄(age)-l0.84×In(El(%));FEV1% pred=141.76-0.78×年龄(age)-14.07×In(EI(%)).经ROC曲线确定对气流受限的判断作用最佳的LDCT定量指标为El.结论 El可用于判别有无气流受限,通过回归方程计算可估测气流受限和肺气肿严重程度.LDCT有望用于COPD的早期诊断.%Objective The purpose of the current study was to deternmine the correlation between the parameters quantified by chest low-dose CT scan (LDCT) and airflow limitation examined by spirometry.Methods This study included 48 patients above 40 years old and with smoking history who underwent LDCT and spirometry on the same day.The regression model was generated on the base of the LDCT value which correlated best to airflow limitation using ROC curve.Results With age,gender and body mass index adjusted,EV and El significantly correlated negatively with FEV1,FEV1%predieted,FEV1/FVC and TLC% predicted (P<0.05),but had no correlation with RV/TLC% predicted ( P>0.05).The regression model were FEV1/FVC%=94.17+25.31 X<gender-0.58×age-10.84×In (EI (%)),FEV1%predicted=141.76-0.78×age-14.07×In (EI(%)).The best LDCT value for airflow limitation estimation was EI.Conclusions El may be used to estimate whether airflow limitation exited and to

  9. Multi-site abdominal tuberculosis mimics malignancy on ~(18)F-FDG PET/CT:Report of three cases

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    18 F-fluorodeoxyglucose positron emission/computed tomography( 18 F-FDG PET/CT)imaging,an established procedure for evaluation of malignancy,shows an increased 18 F-FDG uptake in inflammatory conditions.We present three patients with abdominal pain and weight loss.Conventional imaging studies indicated that abdominal neoplasm and 18 F-FDG PET/CT for assessment of malignancy showed multiple lesions with intense 18 FFDG uptake in abdomen of the three cases.However,the three patients were finally diagnosed wit...

  10. Half-dose abdominal CT with sinogram-affirmed iterative reconstruction technique in children - comparison with full-dose CT with filtered back projection

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Minwook; Kim, Myung-Joon; Lee, Mi-Jung [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Severance Children' s Hospital, 50 Yonsei-ro, Seodaemun-gu, Seoul (Korea, Republic of); Han, Kyung Hwa [Yonsei University College of Medicine, Gangnam Medical Research Center, Biostatistics Collaboration Unit, Seoul (Korea, Republic of)

    2014-07-17

    Iterative reconstruction can be helpful to reduce radiation dose while maintaining image quality. However, this technique has not been fully evaluated in children during abdominal CT. To compare objective and subjective image quality between half-dose images reconstructed with iterative reconstruction at iteration strength levels 1 to 5 (half-S1 to half-S5 studies) and full-dose images reconstructed with filtered back projection (full studies) in pediatric abdominal CT. Twenty-one children (M:F = 13:8; mean age 8.2 ± 5.7 years) underwent dual-source abdominal CT (mean effective dose 4.8 ± 2.1 mSv). The objective image quality was evaluated as noise. Subjective image quality analysis was performed comparing each half study to the full study for noise, sharpness, artifact and diagnostic acceptability. Both objective and subjective image noise decreased with increasing iteration strength. Half-S4 and -S5 studies showed objective image noise similar to or lower than that of full studies. The half-S2 and -S3 studies produced the greatest sharpness and the half-S5 studies were the worst from a blocky appearance. Full and half studies did not differ in artifacts. Half-S3 studies showed the best diagnostic acceptability. Half-S4 and -S5 studies objectively and half-S3 studies subjectively showed comparable image quality to full studies in pediatric abdominal CT. (orig.)

  11. Texture-learning-based system for three-dimensional segmentation of renal parenchyma in abdominal CT images

    Science.gov (United States)

    Peng, Cong-Qi; Chang, Yuan-Hsiang; Wang, Li-Jen; Wong, Yon-Choeng; Chiang, Yang-Jen; Jiang, Yan-Yau

    2009-02-01

    Abdominal CT images are commonly used for the diagnosis of kidney diseases. With the advances of CT technology, processing of CT images has become a challenging task mainly because of the large number of CT images being studied. This paper presents a texture-learning based system for the three-dimensional (3D) segmentation of renal parenchyma in abdominal CT images. The system is designed to automatically delineate renal parenchyma and is based on the texturelearning and the region-homogeneity-based approaches. The first approach is achieved with the texture analysis using the gray-level co-occurrence matrix (GLCM) features and an artificial neural network (ANN) to determine if a pixel in the CT image is likely to fall within the renal parenchyma. The second approach incorporates a two-dimensional (2D) region growing to segment renal parenchyma in single CT image slice and a 3D region growing to propagate the segmentation results to neighboring CT image slices. The criterion for the region growing is a test of region-homogeneity which is defined by examining the ANN outputs. In system evaluation, 10 abdominal CT image sets were used. Automatic segmentation results were compared with manually segmentation results using the Dice similarity coefficient. Among the 10 CT image sets, our system has achieved an average Dice similarity coefficient of 0.87 that clearly shows a high correlation between the two segmentation results. Ultimately, our system could be incorporated in applications for the delineation of renal parenchyma or as a preprocessing in a CAD system of kidney diseases.

  12. Low dose computed tomography of the chest : Applications and limitations

    NARCIS (Netherlands)

    Gietema, H.A.

    2007-01-01

    In areas with a high intrinsic contrast such as the chest, radiation dose can be reduced for specific indications. Low dose chest CT is feasible and cannot only be applied for lung cancer screening, but also in daily routine and for early detection of lung destruction. We showed in a small sample of

  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).

    LENUS (Irish Health Repository)

    Gleeson, T G

    2009-03-01

    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.

  14. Core muscle size assessed by perioperative abdominal CT scan is related to mortality, postoperative complications, and hospitalization after major abdominal surgery

    DEFF Research Database (Denmark)

    Hasselager, Rune; Gögenur, Ismail

    2014-01-01

    to systematically review the literature where core muscle size measurements have been used for risk assessment of patients undergoing major abdominal surgery. METHODS: PubMed and EMBASE databases were searched for studies that investigated core muscle size measured with abdominal CT scans and outcomes after major...... abdominal surgery. RESULTS: Eight studies were found. Four studies investigated postoperative complications related to core muscle area. Three of these studies found significantly increased risk of complications related to low core muscle area. Three studies investigated length of hospitalization, and two......PURPOSE: Risk stratification of patients prior to surgery is important for reduction of postoperative morbidity and mortality. The frailty concept has been put forward as a good predictor of surgical outcomes. Sarcopenia (depletion of muscle mass) can be used to measure frailty. We aimed...

  15. Intra-abdominal spilled gallstones simulating peritoneal metastasis: CT and MR imaging features (2008: 1b)

    Energy Technology Data Exchange (ETDEWEB)

    Karabulut, Nevzat; Tavasli, Birnur; Kiroglu, Yilmaz [Pamukkale University Medical Center, Department of Radiology, Kinikli, Denizli (Turkey)

    2008-04-15

    Laparoscopic cholecystectomy has rapidly become the preferred treatment for symptomatic cholecystolithiasis. However, the procedure is associated with a number of complications, one of which is the spillage of gallstones into the peritoneal cavity. Unretrieved gallstones may cause a wide variety of complications such as abscess, adhesion and small-bowel obstruction, or they may remain asymptomatic and harmless. In the latter case, spilled gallstones in the peritoneal spaces may cause diagnostic difficulty or mimic peritoneal metastasis. We present the computed tomography (CT) and magnetic resonance (MR) imaging features of intra-abdominal gallstone spillage in a case with head and neck neoplasm. Awareness of radiologic features of dropped intraperitoneal gallstones is necessary as they may be mistaken for peritoneal metastases. (orig.)

  16. Liver Segmentation Based on Snakes Model and Improved GrowCut Algorithm in Abdominal CT Image

    Science.gov (United States)

    He, Baochun; Ma, Zhiyuan; Zong, Mao; Zhou, Xiangrong; Fujita, Hiroshi

    2013-01-01

    A novel method based on Snakes Model and GrowCut algorithm is proposed to segment liver region in abdominal CT images. First, according to the traditional GrowCut method, a pretreatment process using K-means algorithm is conducted to reduce the running time. Then, the segmentation result of our improved GrowCut approach is used as an initial contour for the future precise segmentation based on Snakes model. At last, several experiments are carried out to demonstrate the performance of our proposed approach and some comparisons are conducted between the traditional GrowCut algorithm. Experimental results show that the improved approach not only has a better robustness and precision but also is more efficient than the traditional GrowCut method. PMID:24066017

  17. Calcification detection of abdominal aorta in CT images and 3D visualization in VR devices.

    Science.gov (United States)

    Garcia-Berna, Jose A; Sanchez-Gomez, Juan M; Hermanns, Judith; Garcia-Mateos, Gines; Fernandez-Aleman, Jose L

    2016-08-01

    Automatic calcification detection in abdominal aorta consists of a set of computer vision techniques to quantify the amount of calcium that is found around this artery. Knowing that information, it is possible to perform statistical studies that relate vascular diseases with the presence of calcium in these structures. To facilitate the detection in CT images, a contrast is usually injected into the circulatory system of the patients to distinguish the aorta from other body tissues and organs. This contrast increases the absorption of X-rays by human blood, making it easier the measurement of calcifications. Based on this idea, a new system capable of detecting and tracking the aorta artery has been developed with an estimation of the calcium found surrounding the aorta. Besides, the system is complemented with a 3D visualization mode of the image set which is designed for the new generation of immersive VR devices.

  18. Isolated free intra-abdominal fluid on CT in blunt trauma: The continued diagnostic dilemma

    Institute of Scientific and Technical Information of China (English)

    Victor Y.Kong; Damon Jeetoo; Leah C.Naidoo; George V.Oosthuizen; Damian L.Clarke

    2015-01-01

    Purpose: The clinical significance of isolated free fluid (FF) without solid organ injury on computed tomography (CT) continues to pose significant dilemma in the management of patients with blunt abdominal trauma (BAT).Methods: We reviewed the incidence of FF and the clinical outcome amongst patients with blunt abdominal trauma in a metropolitan trauma service in South Africa.We performed a retrospective study of 121 consecutive CT scans over a period of 12 months to determine the incidence of isolated FF and the clinical outcome of patients managed in a large metropolitan trauma service.Results: Of the 121 CTs, FF was identified in 36 patients (30%).Seven patients (6%) had isolated FF.Of the 29 patients who had free fluid and associated organ injuries, 33 organ injuries were identified.86% (25/ 29) of all 29 patients had a single organ injury and 14% had multiple organ injuries.There were 26 solid organ injuries and 7 hollow organ injuries.The 33 organs injured were: spleen, 12: liver, 8;kidney, 5;pancreas, 2;small bowel, 4;duodenum, 1.Six (21%) patients required operative management for small bowel perforations in 4 cases and pancreatic tail injury in 2 cases.All 7 patients with isolated FF were initially observed, and 3 (43%) were eventually subjected to operative intervention.They were found to have an intra-peritoneal bladder rupture in 1 case, a non-expanding zone 3 haematoma in 1 case, and a negative laparotomy in 1 case.Four (57%) patients were successfully managed without surgical interventions.Conclusions: Isolated FF is uncommon and the clinical significance remains unclear.Provided that reliable serial physical examination can be performed by experienced surgeons, an initial non-operative approach should be considered.

  19. Quantitative Aortic Distensibility Measurement Using CT in Patients with Abdominal Aortic Aneurysm: Reproducibility and Clinical Relevance

    Directory of Open Access Journals (Sweden)

    Yunfei Zha

    2017-01-01

    Full Text Available Purpose. To investigate the reproducibility of aortic distensibility (D measurement using CT and assess its clinical relevance in patients with infrarenal abdominal aortic aneurysm (AAA. Methods. 54 patients with infrarenal abdominal aortic aneurysm were studied to determine their distensibility by using 64-MDCT. Aortic cross-sectional area changes were determined at two positions of the aorta, immediately below the lowest renal artery (level 1. and at the level of its maximal diameter (level 2. by semiautomatic segmentation. Measurement reproducibility was assessed using intraclass correlation coefficient (ICC and Bland-Altman analyses. Stepwise multiple regression analysis was performed to assess linear associations between aortic D and anthropometric and biochemical parameters. Results. A mean distensibility of Dlevel  1.=(1.05±0.22×10-5  Pa-1 and Dlevel  2.=(0.49±0.18×10-5  Pa-1 was found. ICC proved excellent consistency between readers over two locations: 0.92 for intraobserver and 0.89 for interobserver difference in level 1. and 0.85 and 0.79 in level 2. Multivariate analysis of all these variables showed sac distensibility to be independently related (R2=0.68 to BMI, diastolic blood pressure, and AAA diameter. Conclusions. Aortic distensibility measurement in patients with AAA demonstrated high inter- and intraobserver agreement and may be valuable when choosing the optimal dimensions graft for AAA before endovascular aneurysm repair.

  20. CFD Modelling of Abdominal Aortic Aneurysm on Hemodynamic Loads Using a Realistic Geometry with CT

    Directory of Open Access Journals (Sweden)

    Eduardo Soudah

    2013-01-01

    Full Text Available The objective of this study is to find a correlation between the abdominal aortic aneurysm (AAA geometric parameters, wall stress shear (WSS, abdominal flow patterns, intraluminal thrombus (ILT, and AAA arterial wall rupture using computational fluid dynamics (CFD. Real AAA 3D models were created by three-dimensional (3D reconstruction of in vivo acquired computed tomography (CT images from 5 patients. Based on 3D AAA models, high quality volume meshes were created using an optimal tetrahedral aspect ratio for the whole domain. In order to quantify the WSS and the recirculation inside the AAA, a 3D CFD using finite elements analysis was used. The CFD computation was performed assuming that the arterial wall is rigid and the blood is considered a homogeneous Newtonian fluid with a density of 1050 kg/m3 and a kinematic viscosity of 4×10-3 Pa·s. Parallelization procedures were used in order to increase the performance of the CFD calculations. A relation between AAA geometric parameters (asymmetry index (β, saccular index (γ, deformation diameter ratio (χ, and tortuosity index (ε and hemodynamic loads was observed, and it could be used as a potential predictor of AAA arterial wall rupture and potential ILT formation.

  1. Application of adaptive non-linear 2D and 3D postprocessing filters for reduced dose abdominal CT.

    Science.gov (United States)

    Borgen, Lars; Kalra, Mannudeep K; Laerum, Frode; Hachette, Isabelle W; Fredriksson, Carina H; Sandborg, Michael; Smedby, Orjan

    2012-04-01

    Abdominal computed tomography (CT) is a frequently performed imaging procedure, resulting in considerable radiation doses to the patient population. Postprocessing filters are one of several dose reduction measures that might help to reduce radiation doses without loss of image quality. To assess and compare the effect of two- and three-dimensional (2D, 3D) non-linear adaptive filters on reduced dose abdominal CT images. Two baseline abdominal CT image series with a volume computer tomography dose index (CTDI (vol)) of 12 mGy and 6 mGy were acquired for 12 patients. Reduced dose images were postprocessed with 2D and 3D filters. Six radiologists performed blinded randomized, side-by-side image quality assessments. Objective noise was measured. Data were analyzed using visual grading regression and mixed linear models. All image quality criteria were rated as superior for 3D filtered images compared to reduced dose baseline and 2D filtered images (P 0.05). There were no significant variations of objective noise between standard dose and 2D or 3D filtered images. The quality of 3D filtered reduced dose abdominal CT images is superior compared to reduced dose unfiltered and 2D filtered images. For patients with BMI < 30 kg/m(2), 3D filtered images are comparable to standard dose images.

  2. MLEM LOW-DOSE CT RECONSTRUCTION BASED ON WAVELET AND FOURTH-ORDER ANISOTROPIC DIFFUSION%基于小波和四阶各向异性扩散的 MLEM 低剂量 CT 重建算法

    Institute of Scientific and Technical Information of China (English)

    张芳; 桂志国; 张权; 董婵婵

    2016-01-01

    In low-dose CT (computed tomography)reconstruction algorithm,traditional maximum likelihood expectation maximisation (MLEM)algorithm will appear chessboard effect along with the increase of the number of iterations,thus cannot effectively suppress noises. For this problem,this paper proposes a low dose CT reconstruction algorithm,which is based on the combination of wavelet shrinkage and fourth-order anisotropic diffusion.It combines the advantages of wavelet shrinkage and anisotropic diffusion,in each iteration,it conducts the discrete stationary wavelet decomposition on the image processed with MLEM reconstruction algorithm,in high frequency part of the wavelet domain it shrinks the wavelet,in low frequency part it uses fourth-order anisotropic diffusion,which has high quality effect in denoising,to eliminate noises,it processes the final residual pulse noise points with the median filter,so that further optimises the image.Simulation experiment results show that the proposed algorithm can effectively remove the noise in low-dose CT image,and has good performances in keeping both the image edges and detailed information,thereby gains the image with high anti-noise performance.%在低剂量计算机断层扫描 CT(computed tomography)重建算法中,传统的最大似然期望最大 MLEM(Maximum Likelihood Expectation Maximization)算法随着迭代次数的增加会出现棋盘效应而不能有效地抑制噪声。针对上述问题提出一种基于小波收缩和四阶各向异性扩散相结合的 MLEM低剂量 CT 重建算法。该算法结合小波收缩和各向异性扩散的优点,在每次迭代中,对 MLEM重建算法处理后的图像进行离散平稳小波分解,在小波域的高频部分进行小波收缩,低频部分使用降噪效果优质的四阶各向异性扩散进行消噪,最后残留的脉冲噪声点通过中值滤波器进行处理,从而进一步优化图像。仿真实验结果表明,该算法

  3. Variability of vascular CT measurement techniques used in the assessment abdominal aortic aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    England, Andrew, E-mail: a.england@liv.ac.u [Directorate of Medical Imaging and Radiotherapy, University of Liverpool, Johnston Building, Quadrangle, Brownlow Hill, Liverpool, L69 3GB (United Kingdom); Niker, Amanda; Redmond, Claire [Directorate of Medical Imaging and Radiotherapy, University of Liverpool, Johnston Building, Quadrangle, Brownlow Hill, Liverpool, L69 3GB (United Kingdom)

    2010-08-15

    Purpose: The aim of this project is to assess the variability of six CT measurement techniques for sizing abdominal aortic aneurysms (AAAs). Method: 37 CT scans with known AAAs were loaded on to a departmental picture archiving and communication system (PACS). A team of three observers, with experience in aortic CT measurements and the PACS performed a series of 2D and 3D measurements on the abdominal aorta. Each observer was asked to measure 3 quantities; anterior-posterior AAA diameter, maximum oblique AAA diameter, maximum aneurysm area using both 2D and 3D techniques. In order to test intra-observer variability each observer was asked to repeat their measurements. All measurements were taken using electronic callipers, under standardised viewing conditions using previously calibrated equipment. 3D measurements were conducted using a computer generated central luminal line (CLL). All measurements for this group were taken perpendicular to the CLL. Results: A total of 972 independent measurements were recorded by three observers. Mean intra-observer variability was lower for 2D diameter measurements (AP 1.3 {+-} 1.6 mm; 2D Oblique 1.2 {+-} 1.3 mm) and 2D areas (0.7 {+-} 1.3 cm{sup 2}) when compared to inter-observer variability (AP 1.7 {+-} 1.9 mm; Oblique 1.6 {+-} 1.7 mm; area 1.1 {+-} 1.5 cm{sup 2}). When comparing 2D with 3D measurements, differences were comparable except for 3D AP diameter and area which had lower inter-observer variability than their 2D counterparts (AP 2D 1.7 {+-} 1.9 mm, 3D 1.3 {+-} 1.3 mm; area 2D 1.1 {+-} 1.5 cm{sup 2}, 3D 0.7 {+-} 0.7 cm{sup 2}). 3D area measurement was the only technique which had equal variability for intra- and inter-observer measurements. Overall observer variability for the study was good with 94-100% of all paired measurements within 5.00 mm/cm{sup 2} or less. Using Pitman's test it can be confirmed that area measurements in the 3D plane have the least variability (r = 0.031) and 3D oblique measurements have

  4. Asbestos Surveillance Program Aachen (ASPA): initial results from baseline screening for lung cancer in asbestos-exposed high-risk individuals using low-dose multidetector-row CT.

    Science.gov (United States)

    Das, Marco; Mühlenbruch, Georg; Mahnken, Andreas H; Hering, K G; Sirbu, H; Zschiesche, W; Knoll, Lars; Felten, Michael K; Kraus, Thomas; Günther, Rolf W; Wildberger, Joachim E

    2007-05-01

    The purpose of this study was to assess the prevalence of lung cancer in a high-risk asbestos-exposed cohort using low-dose MDCT. Of a population of 5,389 former power-plant workers, 316 were characterized as individuals at highest risk for lung cancer according to a lung-cancer risk model including age, asbestos exposure and smoking habits. Of these 316, 187 (mean age: 66.6 years) individuals were included in a prospective trial. Mean asbestos exposure time was 29.65 years and 89% were smokers. Screening was performed on a 16-slice MDCT (Siemens) with low-dose technique (10/20 mAs(eff.); 1 mm/0.5 mm increment). In addition to soft copy PACS reading analysis on a workstation with a dedicated lung analysis software (LungCARE; Siemens) was performed. One strongly suspicious mass and eight cases of histologically proven lung cancer were found plus 491 additional pulmonary nodules (average volume: 40.72 ml, average diameter 4.62 mm). Asbestos-related changes (pleural plaques, fibrosis) were visible in 80 individuals. Lung cancer screening in this high-risk cohort showed a prevalence of lung cancer of 4.28% (8/187) at baseline screening with an additional large number of indeterminate pulmonary nodules. Low-dose MDCT proved to be feasible in this highly selected population.

  5. The in vivo relationship between cross-sectional area and CT dose index in abdominal multidetector CT with automatic exposure control

    Energy Technology Data Exchange (ETDEWEB)

    Meeson, S; Alvey, C M; Golding, S J, E-mail: stuart.meeson@nds.ox.ac.u [Radiology Group, Nuffield Department of Surgery, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU (United Kingdom)

    2010-06-15

    The relationship between patient cross-sectional area and both volume CT dose index (CTDI) and dose length product was explored for abdominal CT in vivo, using a 16 multidetector row CT (MDCT) scanner with automatic exposure control. During a year-long retrospective survey of patients with MDCT for symptoms of abdominal sepsis, cross-sectional areas were estimated using customised ellipses at the level of the middle of vertebra L3. The relationship between cross-sectional area and the exposure parameters was explored. Scans were performed using a LightSpeed 16 (GE Healthcare Medical Systems, Milwaukee, WI) operated with tube current modulation. From a survey of 94 patients it was found that the CTDI increased with the increase in patient cross-sectional area. The relationship was logarithmic rather than linear, with a least-squares fit to the data (R{sup 2} = 0.80). For abdominal CT the cross-sectional area gave a measure of patient size based on the region of the body to be exposed. Exposure parameters increased with increasing cross-sectional area and the greater radiation exposure of larger patients was partly a consequence of their size. Given increasing obesity levels we believe that cross-sectional area and scan length should be added to future dose surveys, allowing patient size to be considered as a factor of relevance when examining population doses.

  6. Evaluation of adverse events and imaging quality in contrast-enhanced abdominal CT using generic CT contrast developed in South Korea: A multicenter prospective observational study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, You Sung [Dept. of Radiology, Ilsan Paik Hospital, College of Medicine, Inje University, Goyang (Korea, Republic of); Jung, Seung Eun; Park, Micheal Yong; Rha, Sung Eun [Dept. of Radiology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Lee, Soo Rim [Dept. of Radiology, Uijeongbu St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu (Korea, Republic of); Hwang, Seong Su [Dept. of Radiology, St. Vincent Hospital, College of Medicine, The Catholic University of Korea, Suwon (Korea, Republic of); Lim, Yeon Soo [Dept. of Radiology, Bucheon St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Bucheon (Korea, Republic of); Park, Jeong Mi [Dept. of Radiology, Yeouido St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2017-02-15

    The purpose of this study is to evaluate the clinical safety and usefulness of the Prosure®300 in contrast-enhanced abdominal CT. This prospective study was approved by our center's Institutional Review Board. This study included 727 patients in four hospitals who underwent contrast-enhanced abdominal CT using Prosure®300 from December 2010 to June 2011. Adverse events were classified into minor and major adverse events. Logistic regression analysis was used to evaluate the relationship between adverse events and patient gender, age, underlying disease, and amount of injected contrast agent. Two radiologists independently evaluated imaging quality as poor, insufficient, sufficient, good, or very good. One hundred seventy-six out of 727 patients complained of adverse events, but most of them were minor adverse events. Five patients complained of dyspnea and one patient had hoarseness, but recovered without treatment. The rate of adverse events was significantly higher in men (p = 0.011), and a greater amount of injected contrast agent was related to a higher rate of adverse events (p = 0.000). Imaging quality was evaluated as 'good' or 'very good' in all cases. Prosure®300, a generic CT contrast agent developed in South Korea, can be used in contrast-enhanced abdominal CT.

  7. 低剂量对比剂在64排螺旋CT主动脉成像中的探讨%Exploration on the use of low dose contrast medium in 64-slice CT imaging of the aorta

    Institute of Scientific and Technical Information of China (English)

    付传明; 徐官珍; 陈伦刚; 徐霖; 龚晓虹; 邹建华; 陈杰

    2011-01-01

    Objective The aim of this study was to explore the effect of different dosees of contrast medium ( CM ) according to different weight indexes in 64-slice CT imaging of the thoraco - abdominal aorta.Methods 40 suspicious patients for aortic disorders were divided into two groups. In the group A, 20 patients with body weight > 60 kg were injected 60 ml contrast medium and 40 ml physiological saline.In the group B, 20 patients with body weight ≤ 60 kg were injected contrast medium in a dose of 1 ml/kg and an appropriate amount of physiological saline. Both groups were injected at the same speed and CM concentration. The body weight, height, blood pressure and heart rate were measured before CT scanning, and the patients received real -time monitoring and triggering scan to measure the CT values and diameters of the aortic intersecting surface at the levels of ascendening aorta, descendening aorta (T7,L2), and aoric bifurcation. Two experienced senior imaging diagnostic doctors evaluated the CT images,and the measured data were statistically analyzed. Results the mean CT values of ascending aorta, thoracic aorta (T7), lumbar aorta (L2) and aortic bifurcation were 331.10 Hu, 342.52 Hu, 308.71 Hu,299.75 Hu and 337. 10 Hu, 325.59 Hu, 322.06 Hu, 308.34 Hu, respectively. The mean diameter ofthe aorta at the four levels were 37.40 mm, 25.12 mm, 17.91 mm, 15.50 mm and 35.20 mm, 23.08 mm,12. 37 mm, 11.80 mm, respectively. The body weights were 72.50 kg and 49.50 kg, the heights were 175.70 cm and 150.50 cm, the systolic blood pressure were 130/78 mmHg and 124/78 mmHg, the heart rates were 76.5 beat/min and 74.6 beat/min, respectively. The intensified CT values of the two groups were not significantly different ( P > 0.05 ), the clarity of the recombined blood vessel branches were not significantly different. The mean diameters of different aortic segments were significantly different ( P < 0.05 ). The body weights and heights were significantly different ( P < 0

  8. False-positive F-18 FDG uptake in PET/CT studies in pediatric patients with abdominal Burkitt's lymphoma.

    Science.gov (United States)

    Riad, Raef; Omar, Walid; Sidhom, Iman; Zamzam, Manal; Zaky, Iman; Hafez, Magdy; Abdel-Dayem, Hussein M

    2010-03-01

    In pediatric patients with abdominal Burkitt's lymphoma, the involvement of the gastrointestinal tract and abdominal lymph nodes are the main presenting feature of the disease. Chemotherapy is the main treatment modality and could be preceded by surgical excision of the abdominal masses. To achieve cure or long-term disease-free survival a balance has to be struck between aggressive chemotherapy and the probability of tumor necrosis secondary to treatment complicated by acute infections, perforation or intestinal bleeding. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (F-18 FDG-PET/CT) has been recommended over conventional imaging modalities for the follow-up of these patients and for monitoring treatment response. As the incidences of postchemotherapy complications are high, the positive predictive value of PET/CT studies in these patients is very low and the false-positive rate is high from acute infections and tumor necrosis. Accordingly, histopathological confirmation of positive lesions on F-18 FDG-PET/CT studies is essential. This is especially important as post-therapy complications might present with nonspecific and nonurgent symptoms. At the same time initiating a second course of salvage chemotherapy is risky. Retrospectively reviewed F-18 FDG-PET/CT studies for 28 pediatric patients with abdominal Burkitt's lymphoma and diffuse large B-cell lymphoma after their treatment with chemotherapy or surgery. Four positive studies were found. All had pathological verification and were because of acute inflammation and tumor necrosis and there was no evidence of viable tumor cells. One patient had multiple recurrent lesions in the abdomen after the initial surgical excision and before starting chemotherapy. The incidence of acute complications in this series is 10.7%. This study confirms the high incidence of tumor necrosis and inflammation after chemotherapy for the abdominal Burkitt's lymphoma and consequently, the incidence of true

  9. The feasibility study of low-dose gem energy spectrum CT colonography in the diagnosis of colonic polyps%低剂量宝石能谱 CT 结肠成像在检测结肠息肉中的可行性研究

    Institute of Scientific and Technical Information of China (English)

    李家言; 黄乔统; 何欣; 黄增超; 刘熙荣; 廖海; 袁文昭; 张锡流; 袁捷; 韦兰珍

    2014-01-01

    Objective To explore the feasibility of low doses of gem energy spectrum CT colonography ( CTC) in detecting polyps of the colon .Methods A total of 50 patients with suspected colonic polyps underwent low-dose gem energy spectrum CTC and endoscopy .The colonic polyps were observed by endoscopy and gem energy spectrum CTC,with the endoscopic finding as gold standard .The coincidence was evaluated for colonic polyps by the gem energy spectrum CTC ,and calculated CT dose index ( CTDIw) in prone was recorded .Results Thirty-eight pa-tients were diagnosed to have colonic polyps by endoscopy and 12 were negative ,the CTC negative diagnosis of colonic polyps in 16 cases and positive 34 cases.Total 79 polyps in 50 patients were found by CTC .For polyp size≥0.5 cm and <0.5 cm, the compliance was 91.07%, and 50.00%,respectively.Conclusion Reduction of the effective dose to 1.01 mGy significantly affects images quality on gemstone energy spectrum CTC ,but the perception of ≥0.5 cm lesion not significantly impaired .%目的:探讨低剂量宝石能谱CT结肠成像( CTC)在检测结肠息肉中的可行性。方法对50例疑似结肠息肉患者行低剂量宝石能谱CTC及内镜检查,以内镜结果作为金标准,计算低剂量宝石能谱CTC检测结肠息肉的符合率,并记录扫描的CT剂量指数( CTDIw )。结果内镜诊断结肠息肉阴性12例,阳性38例;低剂量宝石能谱CTC诊断结肠息肉阴性16例,阳性34例;共发现79个息肉。对于≥0.5 cm的息肉,低剂量宝石能谱CTC的符合率为91.07%,<5 mm的息肉符合率为50%。结论辐射剂量降低至1.01 mGy的宝石能谱CTC检测≥0.5 cm的息肉,与内镜有较高的符合率。

  10. Application of adaptive non-linear 2D and 3D postprocessing filters for reduced dose abdominal CT

    Energy Technology Data Exchange (ETDEWEB)

    Borgen, Lars (Dept. of Radiology, Drammen Hospital, Drammen and Buskerud Univ. College, Drammen (Norway)), Email: lars.borgen@vestreviken.no; Kalra, Mannudeep K. (Massachusetts General Hospital Imaging, Harvard Medical School, Massachusetts General Hospital, Boston (United States)); Laerum, Frode (Dept. of Radiology, Akershus Univ. Hospital, Loerenskog (Norway)); Hachette, Isabelle W.; Fredriksson, Carina H. (ContextVision AB, Linkoeping (Sweden)); Sandborg, Michael (Dept. of Medical Physics, IMH, Faculty of Health Sciences, Linkoeping Univ., County Council of Oestergoetland, Linkoeping (Sweden); Center for Medical Image Science and Visualization, Linkoeping (Sweden)); Smedby, Oerjan (Center for Medical Image Science and Visualization, Linkoeping (Sweden); Dept. of Radiology, Linkoeping Univ., Linkoeping (Sweden))

    2012-04-15

    Background: Abdominal computed tomography (CT) is a frequently performed imaging procedure, resulting in considerable radiation doses to the patient population. Postprocessing filters are one of several dose reduction measures that might help to reduce radiation doses without loss of image quality. Purpose: To assess and compare the effect of two- and three-dimensional (2D, 3D) non-linear adaptive filters on reduced dose abdominal CT images. Material and Methods: Two baseline abdominal CT image series with a volume computer tomography dose index (CTDI{sub vol}) of 12 mGy and 6 mGy were acquired for 12 patients. Reduced dose images were postprocessed with 2D and 3D filters. Six radiologists performed blinded randomized, side-by-side image quality assessments. Objective noise was measured. Data were analyzed using visual grading regression and mixed linear models. Results: All image quality criteria were rated as superior for 3D filtered images compared to reduced dose baseline and 2D filtered images (P < 0.01). Standard dose images had better image quality than reduced dose 3D filtered images (P < 0.01), but similar image noise. For patients with body mass index (BMI) < 30 kg/m2 however, 3D filtered images were rated significantly better than normal dose images for two image criteria (P < 0.05), while no significant difference was found for the remaining three image criteria (P > 0.05). There were no significant variations of objective noise between standard dose and 2D or 3D filtered images. Conclusion: The quality of 3D filtered reduced dose abdominal CT images is superior compared to reduced dose unfiltered and 2D filtered images. For patients with BMI < 30 kg/m2, 3D filtered images are comparable to standard dose images

  11. Differential diagnosis of incidentally detected adrenal masses revealed on routine abdominal CT

    Energy Technology Data Exchange (ETDEWEB)

    Ctvrtlik, Filip [Department of Radiology, University Hospital Olomouc, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)], E-mail: ctvrtlikf@seznam.cz; Herman, Miroslav [Department of Radiology, University Hospital Olomouc, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)], E-mail: miroslav.herman@fnol.cz; Student, Vladimir [Department of Urology, University Hospital Olomouc, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)], E-mail: studentv@seznam.cz; Ticha, Vlastislava [Department of Pathology, University Hospital Olomouc, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)], E-mail: tichym@tunw.upol.cz; Minarik, Jiri [Department of Internal medicine, University Hospital Olomouc, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)], E-mail: abretina@email.cz

    2009-02-15

    Purpose: The aim of this study was to compare CT findings of adrenal incidentalomas with a definitive histological diagnosis in order to establish CT features characteristic for individual types of lesions. Patients and methods: The retrospective study comprised of patients with adrenal lesions detected on abdominal CT. The patients with these incidental findings subsequently underwent adrenalectomy. The adrenalectomy was followed by a histological assessment of the expansion process. The study consisted of 62 adrenal expansions found in 55 patients (in seven patients bilateral lesions were found). According to the definitive histological diagnosis after adrenalectomy, the lesions were divided into the following six groups: primary adrenocortical carcinoma (n = 4), metastasis (n = 7), adrenocortical adenoma (n = 37), pheochromocytoma (n = 9), myelolipoma (n = 2), and others (n = 3). CT observations were categorized as follows: size, shape, margins, density, side of the expansion, homogeneous or heterogeneous density before and after contrast application, presence of central hypodensity, presence of central calcifications and fat deposits. Statistical analysis was carried out using the {chi}{sup 2}-test, Kruskal-Wallis test and Mann-Whitney test. To estimate the differences between the subgroups, the t-test was used. For the evaluation of the mutual relations of maximum size, mean size, and volume, regression analysis (coefficient of determination R{sup 2}) was used. Results: The correlation and regression analysis suggest that there will be no statistically significant error if the maximum size measurements are used instead of the mean size or volume measurements of the lesion. Sensitivity, specificity, accuracy, positive predictive value, negative predictive value for distinguishing adenomas and non-adenomas using a cut-off diameter of 41.5 mm were 81.1%, 70.0%, 77.2%, 83.3%, 66.7%, respectively; using the non-contrast density threshold of 23 HU, they were 89

  12. Incidental unilateral tuberculous sacroiliitis detected by 18F-FDG PET/CT in a patient with abdominal tuberculosis.

    Directory of Open Access Journals (Sweden)

    Domenico Albano

    2017-06-01

    Full Text Available Tuberculosis is a systemic disease which involves skeletal and articular system very rarely. Osteoarticular tuberculosis commonly occurs in the vertebral column and more rarely in the sacroiliac joints. In this study, we report a 44-years-old male patient with low-grade fever, malabsorption syndrome, abdominal and pelvic ascites and low-back pain, that underwent 18F-FDG PET/CT for identifying the cause of signs and symptoms after a negative abdominal CT and negative thorax radiography. The study revealed increased tracer uptake at the peritoneal ascites and at the right sacroiliac joint in absence of bone alteration suggesting a sacroiliitis. Staining of the ascitic fluid was positive for acid-fast bacilli (Ziehl–Neelsen and in the subsequent abdominal paracentesis Mycobacterium Tuberculosis was isolated; the final diagnosis was abdominal tuberculosis with a sacroiliac joint involvement. The patient started antitubercular therapy for 6 months and the clinical conditions were resolved, in particular both back pain and ascites disappeared.

  13. Prognostic Value of Gastric Bare Area & Left Adrenal Gland Involvement in Acute Pancreatitis on Abdominal CT SCAN

    Directory of Open Access Journals (Sweden)

    Saeed Naghibi

    2009-01-01

    Full Text Available "nIntroduction: The CT severity index (CTSI proposed by Baithazar is a well-defined scoring system and has proved to be an excellent prognostic tool in predicting complications and mortality in patients with acute pancreatitis .But new investigations demonstrate that the other findings on abdominal CT scan in acute pancreatitis impression on prognostic outcome (involvement of abdominal viscera. Therefore the newer scoring system has been proposed. In our study the involvement of gastric bare area & left adrenal gland in CT scan is usually associated with a more severe clinical course. "nMaterials and Methods: This study was a retrospective & prospective evaluation in 22-Bahman Hospital of AZAD University of Mashhad from 2006 to 2008 .78 patients with acute pancreatitis (based on a typical clinical presentation & an elevated serum amylase level and "or pathologic findings had undergone the abdominal spiral CT scan with oral & IV contrast (if necesary. 28 cases were excluded from the study population for the following reasons: CT was not performed (n=10 ; CT images were not available (n=13; inadequate data analysis (n=2; and acute pancreatitis was not the first episode (n=3. "nFollow-up CT was performed within 1 week after the initial CT. Leaving 50 patients in our study there were 32 men and 18 women in the age range of 21-82 years (50.5+_ 18.2 years. All the patients underwent unenhanced CT followed by dual-phase contrast-enhanced CT. The arterial and portal venous phase data acquisition started at 25-30s and 60-65s after injection of contrast. Then two experienced abdominal radiologists recorded the findings of CT scan including the size,contour and density of the pancreas and manifestations of peripancreatic inflammation as well as the GBAI and LAGI involvement (haziness and streaky density with fluid collection in the gastric bare area and deformity with ill-defined margin and hypodensity of the left adrenal gland on unenhanced or contrast

  14. Automated tube potential selection for standard chest and abdominal CT in follow-up patients with testicular cancer: comparison with fixed tube potential

    Energy Technology Data Exchange (ETDEWEB)

    Gnannt, Ralph; Winklehner, Anna; Frauenfelder, Thomas; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Eberli, Daniel [University Hospital Zurich, Clinic for Urology, Zurich (Switzerland); Knuth, Alexander [University Hospital Zurich, Clinic for Oncology, Zurich (Switzerland)

    2012-09-15

    To evaluate prospectively, in patients with testicular cancer, the radiation dose-saving potential and image quality of contrast-enhanced chest and abdominal CT with automated tube potential selection. Forty consecutive patients with testicular cancer underwent contrast-enhanced arterio-venous chest and portal-venous abdominal CT with automated tube potential selection (protocol B; tube potential 80-140 kVp), which is based on the attenuation of the CT topogram. All had a first CT at 120 kVp (protocol A) using the same 64-section CT machine and similar settings. Image quality was assessed; dose information (CTDI{sub vol}) was noted. Image noise and attenuation in the liver and spleen were significantly higher for protocol B (P < 0.05 each), whereas attenuation in the deltoid and erector spinae muscles was similar. In protocol B, tube potential was reduced to 100 kVp in 18 chest and 33 abdominal examinations, and to 80 kVp in 5 abdominal CT examinations; it increased to 140 kVp in one patient. Image quality of examinations using both CT protocols was rated as diagnostic. CTDI{sub vol} was significantly lower for protocol B compared to protocol A (reduction by 12%, P < 0.01). In patients with testicular cancer, radiation dose of chest and abdominal CT can be reduced with automated tube potential selection, while image quality is preserved. (orig.)

  15. The effect of low-dose β-blocker on heart rate and heart rate variability in health subjects wth a resting heart rate of less than 65 beats per minute: Effect on the quality of prospective electrocardiography-gated coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chul Hwan; Kim, Tae Hoon [Dept. of Radiology and Research Institute of Radiological Science, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Lee, Sang Min [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Hong, Yoo Jin [Dept. of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2015-02-15

    We assessed the effect of a low-dose β-blocker on heart rate (HR), HR variability (HRV) and image quality of prospective electrocardiography-gated coronary CT angiography (CCTA) in healthy subjects with low HR. CCTA was performed with a 64-slice CT in 75 subjects with a HR of less than 65 beats per minute (bpm). Subjects were divided into 2 groups: Group 1 (G1), 35 with a low dose β-blocker; and Group 2 (G2), 40 without pre-medication. The image quality (IQ) of the CCTA was assessed on a 4-point grading scale (1, poor; 4, excellent). Initial HR (bpm) was not different between the 2 groups. HR during CCTA was lower in G1 than G2 (50.3 ± 5.6 vs. 53.3 ± 4.8, p = 0.016). HRV was not different between the 2 groups. Per-segment analysis showed better IQ at the mid-segment of the right coronary artery (3.0 ± 0.9 vs. 2.5 ± 1.1, p = 0.039) and the first diagonal branch (3.4 ± 0.6 vs. 3.1 ± 0.7, p = 0.024), in the G1 than the G2 group, respectively. The IQ was negatively correlated with HR, but no correlation was found between HRV and IQ. The IQs in the per-vessel analysis were not different between the 2 groups. Low-dose β-blocker reduced HR and improved the IQ of CCTA in a few segments, even at a HR of less than 65 bpm. However the effect was limited.

  16. Determination of the optimal energy level in spectral CT imaging for displaying abdominal vessels in pediatric patients

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Di, E-mail: hudi0415@163.com [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Yu, Tong, E-mail: hemophilia@126.com [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Duan, Xiaomin, E-mail: potatocat@yeah.net [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Peng, Yun, E-mail: ppengyun@yahoo.com [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Zhai, Renyou, E-mail: zhairenyou@163.com [Beijing Chaoyang Hospital, Capital Medical University, Imaging Center, No. 8, Gongti South Road, Chaoyang District, Beijing 100020 (China)

    2014-03-15

    Purpose: To determine the optimal energy level in contrast-enhanced spectral CT imaging for displaying abdominal vessels in pediatric patients. Materials and methods: This retrospective study was institutional review board approved. 15 children (8 males and 7 females, age range, 6–15 years, mean age 10.1 ± 3.1 years) underwent contrast-enhanced spectral CT imaging for diagnosing solid tumors in abdomen and pelvic areas were included. A single contrast-enhanced scan was performed using a dual energy spectral CT mode with a new split contrast injection scheme (iodixanol at 1–1.5 ml/kg dose. 2/3 first, 1/3 at 7–15 s after the first injection). 101 sets of monochromatic images with photon energies of 40–140 keV with 1 keV interval were reconstructed. Contrast-noise-ratio (CNR) for hepatic portal or vein were generated and compared at every energy level to determine the optimal energy level to maximize CNR. 2 board-certified radiologists interpreted the selected image sets independently for image quality scores. Results: CT values and CNR for the vessels increased as photon energy decreased from 140 to 40 keV: (CT value: 48.29–570.12 HU, CNR: 0.08–14.90) in the abdominal aorta, (58.48–369.73 HU, 0.64–5.87) in the inferior vena cava, and (58.48–369.73 HU, 0.06–6.96) in the portal vein. Monochromatic images at 40–50 keV (average 42.0 ± 4.67 keV) could display vessels above three levels clearly, and with excellent image quality scores of 3.17 ± 0.58 (of 4) (k = 0.50). The CNR values at the optimal energy level were significantly higher than those at 70 keV, an average energy corresponding to the conventional 120 kVp for abdominal CT imaging. Conclusion: Spectral CT imaging provides a set of monochromatic images to optimize image quality and enhance vascular visibility, especially in the hepatic portal and vein systems. The best CNR for displaying abdominal vessels in children was obtained at 42 keV photon energy level.

  17. Application Value of Dual-source CT Low-dose Scanning in the Diagnosis of Adenoidal Hypertrophy in Children%双源CT低剂量扫描在诊断儿童腺样体肥大中的应用价值

    Institute of Scientific and Technical Information of China (English)

    王守玺

    2014-01-01

    Objective To evaluate and analyze the application value of dual-source CT low-dose scanning in the diagnosis of ade-noidal hypertrophy in children, so as to provide reliable reference for future clinical diagnostic work. Methods 76 cases of children clinically diagnosed as adenoidal hypertrophy admitted in our hospital from January, 2011 to December, 2013 were extracted. And they were divided into the control group and the observation group in accordance with the order of admission. The control group was given dual-source CT conventional-dose scanning, and the observation group was given dual-source CT low-dose scanning, the image quality, radiation dose and diagnostic results of both groups were compared and analyzed. Results There was no signifi-cant difference in the result of nasopharyngeal anatomy display between the observation group and the control group ( P>0.05), but the difference in adenoid CT value and radiation dose between the two groups was significant (P0.05),两组患儿腺样体CT值和辐射剂量比较存在差异有统计学意义(P<0.05)。结论经双源CT低剂量扫描可对儿童腺样体肥大做出准确的诊断,且其安全性较常规剂量扫描更高,临床诊断价值显著,值得关注并推广。

  18. Abdominal and pelvic CT in cases of suspected abuse: can clinical and laboratory findings guide its use?

    Energy Technology Data Exchange (ETDEWEB)

    Trout, Andrew T.; Strouse, Peter J. [University of Michigan Health System, C.S. Mott Children' s Hospital, Department of Radiology, Ann Arbor, MI (United States); Mohr, Bethany A. [University of Michigan Health System, C.S. Mott Children' s Hospital, Department of Pediatrics, Ann Arbor, MI (United States); Khalatbari, S.; Myles, Jamie D. [University of Michigan, Michigan Institute for Clinical and Health Research, Ann Arbor, MI (United States)

    2011-01-15

    Incomplete history and concern for occult injury in suspected child abuse occasionally results in CT screenings of the abdomen and pelvis. At our institution, we noted that these exams were infrequently positive. To identify clinical or laboratory criteria that may predict intra-abdominal injury and guide the use of abdominal and pelvic CT in this population. This retrospective review involved 68 children older than 36 months who had a CT of the abdomen/pelvis for suspected abuse. CT results and patient charts were reviewed for physical exam and historical and laboratory variables. CTs were positive in 16% of patients (11/68). Hypoactive/absent bowel sounds (P = 0.01, specificity = 94.7%) and AST and ALT values greater than twice normal (P = 0.004 and P = 0.003 respectively, NPV = 93.6%) were significantly associated with positive CTs. Multiple abnormal physical exam or laboratory findings were also significantly associated with positive CTs (P = 0.03 and P = 0.002 respectively, specificity = 91.3% and NPV = 93.6% respectively). CTs of the abdomen and pelvis are infrequently positive in cases of suspected abuse. To reduce radiation exposure, CTs should only be ordered if there are findings indicating that they may be positive. In our population, these findings include absent/hypoactive bowel sounds, LFTs greater than twice normal and {>=}2 abnormal labs or physical exam findings. (orig.)

  19. Endovascular abdominal aortic aneurysm repair: surveillance of endoleak using maximum transverse diameter of aorta on non-enhanced CT

    Energy Technology Data Exchange (ETDEWEB)

    Nagayama, Hiroki; Sueyoshi, Eijun; Sakamoto, Ichiro; Uetani, Masataka [Dept. of Radiology, Nagasaki Univ. School of Medicine, Nagasaki (Japan)], E-mail: sueyo@nagasaki-u.ac.jp

    2012-07-15

    Background. Repeat volumetric analysis of abdominal aortic aneurysm (AAA) after endovascular AAA repair (EVAR) is time-consuming and requires advanced processing, dedicated equipment, and skilled operators. Purpose. To clarify the validity of measuring the maximal short-axis diameter (Dmax) of AAA in follow-up non-enhanced axial CT as a means of detecting substantial endoleaks after EVAR. Material and Methods. CT images were retrospectively reviewed in 47 patients (7 women, 40 men; mean age, 76.2 years) who had no endoleak on initial contrast-enhanced CT after EVAR. Regular follow-up CT studies were performed every 6 months. At each CT study, the Dmax on the CT axial image was measured and compared with that on the last CT (115 data-sets). Contrast-enhanced CT was regarded as the standard of reference to decide the presence or absence of endoleaks. The appearance of endoleak was defined as the end point of this study. Results. Endoleaks were detected in 17 patients during the follow-up period. Mean Dmax changes for 6 months were significant between positive and negative endoleak cases (1.8 {+-} 1.9 vs. -1.1 {+-} 3.0 mm, P < 0.0001). When the Dmax change {<=} 0 mm for 6 months was used as the threshold for negative endoleak, the sensitivity, specificity, positive predictive value, and negative predictive value were 74.5, 82.4, 96.1, and 35.9%, respectively. When Dmax change {<=}-1 mm was used as the threshold, the sensitivity, specificity, PPV, and NPV were 38.8, 100, 100, and 22.1%, respectively. Conclusion. Contrast-enhanced CT is not required for the evaluation of endoleaks when the Dmax decreases by at least 1 mm over 6 months after EVAR.

  20. Low-dose head computed tomography in children: a single institutional experience in pediatric radiation risk reduction: clinical article.

    Science.gov (United States)

    Morton, Ryan P; Reynolds, Renee M; Ramakrishna, Rohan; Levitt, Michael R; Hopper, Richard A; Lee, Amy; Browd, Samuel R

    2013-10-01

    In this study, the authors describe their experience with a low-dose head CT protocol for a preselected neurosurgical population at a dedicated pediatric hospital (Seattle Children's Hospital), the largest number of patients with this protocol reported to date. All low-dose head CT scans between October 2011 and November 2012 were reviewed. Two different low-dose radiation dosages were used, at one-half or one-quarter the dose of a standard head CT scan, based on patient characteristics agreed upon by the neurosurgery and radiology departments. Patient information was also recorded, including diagnosis and indication for CT scan. Six hundred twenty-four low-dose head CT procedures were performed within the 12-month study period. Although indications for the CT scans varied, the most common reason was to evaluate the ventricles and catheter placement in hydrocephalic patients with shunts (70%), followed by postoperative craniosynostosis imaging (12%). These scans provided adequate diagnostic imaging, and no patient required a follow-up full-dose CT scan as a result of poor image quality on a low-dose CT scan. Overall physician comfort and satisfaction with interpretation of the images was high. An additional 2150 full-dose head CT scans were performed during the same 12-month time period, making the total number of CT scans 2774. This value compares to 3730 full-dose head CT scans obtained during the year prior to the study when low-dose CT and rapid-sequence MRI was not a reliable option at Seattle Children's Hospital. Thus, over a 1-year period, 22% of the total CT scans were able to be converted to low-dose scans, and full-dose CT scans were able to be reduced by 42%. The implementation of a low-dose head CT protocol substantially reduced the amount of ionizing radiation exposure in a preselected population of pediatric neurosurgical patients. Image quality and diagnostic utility were not significantly compromised.

  1. Application of Low-dose CT Scanning in the Evaluation of Upper Airway Obstruction in Children with Adenoid Hypertrophy%低剂量CT对儿童腺样体肥大上气道阻塞的客观评价

    Institute of Scientific and Technical Information of China (English)

    蒋山姗; 徐嵩; 丁琼; 郭建东; 刘西; 唐伟华

    2014-01-01

    目的:研究低剂量CT三维重建技术在儿童腺样体肥大所致上气道顺应性改变的客观评估中的临床应用价值。方法19例腺样体肥大患儿接受CT低剂量扫描和症状计分表调查,与17例正常儿童的CT低剂量扫描后三维测量指标进行对照。结果腺样体肥大组患儿单位鼻咽腔容积(rNPV)及鼻咽气道最狭窄处面积比值(rNPA)与对照组比较差异均有统计学意义(rNPV值P<0.01、rNPA值P<0.05);rNPA与症状严重程度呈负相关(r=-0.659,P<0.01), rNPV值与症状计分无明显相关(P>0.05)。结论低剂量CT三维重建技术可用于腺样体肥大所致儿童上气道阻塞的客观定量评估。在解释测量结果与主观症状关系时rNPA应作为主要参考指标。%Objective To evaluate the clinical application value of Low-dose CT scanning and three-dimensional reconstruction method in the objective evaluation of upper airway obstruction caused by adenoid hypertrophy in children. Methods nineteen patients with adenoid hypertrophy were examined with low-dose CT and questionnaire. The measured values of 3D reconstruction were compared with those of 17 normal children. Results There were significant differences between the study group and the control group in rNPV(P0.05). Conclusion Low-dose CT scanning with 3D reconstruction method was an objective and quantitative method for the evaluation of upper airway in children with adenoid hypertrophy. The relationship of the measured values and subjective symptoms can be evaluated by rNPA.

  2. Retropsoas hernia as a cause of chronic abdominal pain: CT diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.E. [Div. of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (United States); Strauch, E.D. [Division of Pediatric Surgery, Johns Hopkins Hospital, Baltimore, Maryland (United States)

    1998-05-01

    Congenital retropsoas small bowel herniation is reported as the cause of long-standing recurrent abdominal pain in a teenage girl. Knowledge of this entity is important for differential diagnosis of abdominal pain, mass, or retroperitoneal gas and fluid, and for avoiding complications of percutaneous renal interventions. (orig.) With 2 figs., 6 refs.

  3. CT-based abdominal aortic calcification score as a surrogate marker for predicting the presence of asymptomatic coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    An, Chansik; Lee, Hye-Jeong; Ahn, Sung Soo; Choi, Byoung Wook; Kim, Myeong-Jin; Chung, Yong Eun [Severance Hospital, Yonsei University College of Medicine, Department of Radiology, Research Institute of Radiological Science, 50 Yonsei-Ro, Seodaemun-Gu, Seoul (Korea, Republic of); Lee, Hye Sun [Yonsei University College of Medicine, Biostatistics Collaboration Unit, Department of Research Affairs, Seoul (Korea, Republic of)

    2014-10-15

    To assess the value of a CT-based abdominal aortic calcification (AAC) score as a surrogate marker for the presence of asymptomatic coronary artery disease (CAD). The AAC scores of 373 patients without cardiac symptoms who underwent both screening coronary CT angiography and abdominal CT within one year were calculated according to the Agatston method. Logistic regression was used to derive two multivariate models from traditional cardiovascular risk factors, with and without AAC scores, to predict the presence of CAD. The AAC score and the two multivariate models were compared by calculating the area under the receiver operating characteristic curve (AUC) and the net reclassification improvement (NRI). The AAC score alone showed a marginally higher AUC (0.823 vs. 0.767, P = 0.061) and significantly better risk classification (NRI = 0.158, P = 0.048) than the multivariate model without AAC. The multivariate model using traditional factors and AAC did not show a significantly higher AUC (0.832 vs. 0.823, P = 0.616) or NRI (0.073, P = 0.13) than the AAC score alone. The optimal cutoff value of the AAC score for predicting CAD was 1025.8 (sensitivity, 79.5 %; specificity, 75.9 %). AAC scores may serve as a surrogate marker for the presence or absence of asymptomatic CAD. (orig.)

  4. Dual-source CT Low-dose Technology Used in Suspected Lesions in Patients with Chest CT Examination%双源CT低剂量技术在疑是胸部病变患者CT检查中的应用

    Institute of Scientific and Technical Information of China (English)

    刘素芝; 郭占林; 张颖

    2016-01-01

    目的:研究双源CT低剂量技术在疑是胸部病变患者CT检查中的应用价值。方法选取2013年11月至2014年11月来我院接受检查的161例疑是胸部病变患者,按照患者前来就诊的先后顺序将患者分为7组,每组23例,对7组患者分别采用常规管电流量110mAs和低管电流量105,100,95,90,85,80 mAs进行测量,比较各组患者肺动脉分叉平面肺动脉信噪比、肺动脉-竖脊肌对比噪声比、降主动脉信噪比、降主动脉-竖脊肌对比噪声比、图像主观质量评分及病变检出情况。结果随着放射剂量的降低,肺动脉和降主动脉的信噪比逐渐降低(P<0.05);各组图像质量评分随着球管电流量的减小而降低(P<0.05);80mAs低管电流量组病变检出率为81.25%较其余各组显著较低(P<0.05)。结论双源CT低剂量技术能在疑是胸部病变患者CT检查中给予准确判断,能有效降低放射对人体造成的伤害,建议行双源CT检查时采用85mAs的参考管电流量,既能获得准确清晰的诊断图像又能明显降低患者所受辐射剂量。%Objective to study the dual-source CT low-dose technology in the application of CT examination in patients with suspected chest lesions. Methods Selection in November 2013 to November 2014 in our hospital for inspection of 161 patients with suspected chest lesions, according to the order of patients in the hospital can be divided into 7 groups, each group of 23 cases, the 7 groups patients respectively using conventional pipe electricity flow 110 mAs and low electrical flow 105, 100, 95, 90, 85, 80 mAs measurement, comparison between groups in patients with pulmonary artery bifurcation plane the signal-to-noise ratio of pulmonary artery, pulmonary artery - sma vertical contrast to noise ratio, the descending aorta signal-to-noise ratio, the descending aorta-sma vertical contrast to noise ratio, the subjective image quality score and lesion detection

  5. Quantitative X-ray CT analysis of calcification of the abdominal aorta and its relationship to obesity

    Energy Technology Data Exchange (ETDEWEB)

    Shinagawa, Toshio; Hiraiwa, Yoshio; Mizuno, Seio; Kusunoki, Norio; Nitta, Yu; Matsubara, Takao; Iwainaka, Yoichi; Konishi, Hideo (Toyama Red Cross Hospital (Japan))

    1992-04-01

    Quantitative analysis of abdominal aorta calcification by X-ray CT is useful method for non-invasive diagnosis of atherosclerosis. We recently examined the relationship between the X-ray CT measurement of abdominal aorta calcification and the degree of obesity. For this purpose, the body mass index (BMI) and the subcutaneous fat thickness (determined by X-ray CT at the umbilical level) were analyzed in relation to the abdominal aorta calcification index (ACI) in 845 patients (453 males and 392 females aged 40-79 years). Patients with BMI under 20 were classified as 'lean', those with BMI between 20-26 as 'normal' and those with BMI over 26 as 'obese'. 1. Among males, the ACI was highest in lean individuals and lowest in obese individuals. The difference in ACI between lean and obese males was significant in the middle aged group (40-65 years). Among females, no relationship was observed between the degree of obesity and ACI. 2. Among males, ACI was higher in individuals with low subcutaneous fat thickness and lower in individuals with greater subcutaneous fat thickness. The difference was significant in the middle aged group. Among females, no relationship was observed between the two parameters. 3. When the visceral fat to subcutaneous fat ratio (V/S) in 85 males and females aged 60-69 years was analyzed in relation to ACI, ACI tended to decrease as the V/S increased, in both males and females. 4. Relationships between BMI and subcutaneous fat thickness, between BMI and lipids and between lipids and ACI were also analyzed. (author).

  6. Automatic coronary calcium scoring in low-dose chest computed tomography

    NARCIS (Netherlands)

    Isgum, I.; Prokop, M.; Niemeijer, M.; Viergever, M.; Ginneken, B. van

    2012-01-01

    The calcium burden as estimated from non-ECGsynchronized CT exams acquired in screening of heavy smokers has been shown to be a strong predictor of cardiovascular events. We present a method for automatic coronary calcium scoring with low-dose, non-contrast-enhanced, non-ECG-synchronized chest CT. F

  7. 基于预扫描正则化与稀疏约束重建的低剂量CT灌注成像%Low-dose CT Perfusion Imaging Based on Pre-scan Regulation and on Reconstruction with Sparsity Constraints

    Institute of Scientific and Technical Information of China (English)

    莫纪江; 周爱珍; 王聪; 梅颖洁; 冯衍秋

    2012-01-01

    The long-period CT perfusion imaging leads to an excess amount of radiation dose to the patient. However, the radiation dose could be significantly reduced if a previous normal-dose image is acquired before a set of low-dose scans of perfusion, and a filtering processing is performed on the differences between the current low-dose images and the previous normal-dose image, then the results are added to the previous image. But the selection of plenty of parameters makes the algorithm complicated. This paper proposes an innovative approach performed in sinogram domain instead of in image domain. First a normal-dose image and a set of low-dose projection data are acquired before the perfusion. Second the perfusion information is commendably reconstructed with sparsity constraints of the' differences between current low-dose perfusion sinograms and previous low-dose sinogram. Finally, the reconstructed perfusion information is added to the previous normal-dose image. The proposed method was validated by simulated experiments with a set of brain CT perfusion images, which showed that the new method provided more accurate perfusion informations the time-attenuation curve was more close to that for normal-dose scan and the mean transit time more repeatable.%CT灌注成像中患者会受到长时间的X线照射,在灌注前预先扫描一幅正常剂量图像,在后续灌注过程中进行低剂量采集,将所获低剂量图像与参考图像做减影并进行滤波处理以获得灌注信息,然后叠加到正常剂量图像中,可以非常显著地降低CT灌注成像中辐射剂量,然而,当剂量非常低的时候,重建图像会受到噪声与伪影干扰.本文基于类似的预扫描正则化数据采集方案,分别进行正常剂量和低剂量预扫描,然后利用相同的低剂量进行后续灌注过程的扫描,将所采集低剂量数据与预扫描的低剂量数据在投影域作差,然后在重建中引入稀疏性约束,以获得更准确的灌注信

  8. Locoregional IL-2 low dose applications for gastrointestinal tumors

    Institute of Scientific and Technical Information of China (English)

    Zachary Krastev; Willem Den Otter; V Koltchakov; R Tomova; S Deredjian; A Alexiev; D Popov; B Tomov; Jan-Willem Koten; John Jacobs

    2005-01-01

    AIM: To explore the feasibility of local interleukin 2 (IL-2)in patients with different forms of abdominal cancer. This required experimentation with the time interval between IL-2 applications and the methods of application.METHODS: Sixteen patients with stages Ⅲ and Ⅳ of gastrointestinal malignancies (primary or metastatic) who were admitted to our Department of Gastroenterology were treated with locoregionally applied IL-2 in low doses.RESULTS: No major problems applying locoregional IL-2 were encountered. In 6 out of 16 patients, a modest but clinically worthwhile improvement was obtained. Adverse effects were minimal, The therapeutic scheme was well tolerated, even in patients in a poor condition.CONCLUSION: This study demonstrates the feasibility of low dose locoregional IL-2 application in advanced abdominal cancer. Local IL-2 therapy gives only negligible adverse effects. The results suggest that it is important to apply intratumorally. Local IL-2 may be given adjunct to standard therapeutic regimes and does not imply complex surgical interventions. These initial results are encouraging.

  9. Low-dose computed tomography to diagnose fetal bone dysplasias.

    Science.gov (United States)

    Montoya Filardi, A; Guasp Vizcaíno, M; Gómez Fernández-Montes, J; Llorens Salvador, R

    We present a case of cleidocranial dysplasia diagnosed by low-dose fetal computed tomography (CT) in the 25th week of gestation. Severe bone dysplasia was suspected because of the fetus' low percentile in long bones length and the appearance of craniosynostosis on sonography. CT found no abnormalities incompatible with life. The effective dose was 5 mSv, within the recommended range for this type of examination. Low-dose fetal CT is a new technique that makes precision study of the bony structures possible from the second trimester of pregnancy. In Spain, abortion is legal even after the 22nd week of gestation in cases of severe fetal malformations. Therefore, in cases in which severe bone dysplasia is suspected, radiologists must know the strategies for reducing the dose of radiation while maintaining sufficient diagnostic quality, and they must also know which bony structures to evaluate. Copyright © 2016 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Development of automated extraction method of biliary tract from abdominal CT volumes based on local intensity structure analysis

    Science.gov (United States)

    Koga, Kusuto; Hayashi, Yuichiro; Hirose, Tomoaki; Oda, Masahiro; Kitasaka, Takayuki; Igami, Tsuyoshi; Nagino, Masato; Mori, Kensaku

    2014-03-01

    In this paper, we propose an automated biliary tract extraction method from abdominal CT volumes. The biliary tract is the path by which bile is transported from liver to the duodenum. No extraction method have been reported for the automated extraction of the biliary tract from common contrast CT volumes. Our method consists of three steps including: (1) extraction of extrahepatic bile duct (EHBD) candidate regions, (2) extraction of intrahepatic bile duct (IHBD) candidate regions, and (3) combination of these candidate regions. The IHBD has linear structures and intensities of the IHBD are low in CT volumes. We use a dark linear structure enhancement (DLSE) filter based on a local intensity structure analysis method using the eigenvalues of the Hessian matrix for the IHBD candidate region extraction. The EHBD region is extracted using a thresholding process and a connected component analysis. In the combination process, we connect the IHBD candidate regions to each EHBD candidate region and select a bile duct region from the connected candidate regions. We applied the proposed method to 22 cases of CT volumes. An average Dice coefficient of extraction result was 66.7%.

  11. Radiation dose reduction sinogram affirmed iterative reconstruction and automatic tube voltage modulation(CARE kV) in abdominal CT

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyun Joo; Chung, Yong Eun; Lee, Young Han; Choi, Jin Young; Park, Mi Suk; Kim, Myeong Jin; Kim, Ki Whang [Dept. of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2013-12-15

    To evaluate the feasibility of sinogram-affirmed iterative reconstruction (SAFIRE) and automated kV modulation (CARE kV) in reducing radiation dose without increasing image noise for abdominal CT examination. This retrospective study included 77 patients who received CT imaging with an application of CARE kV with or without SAFIRE and who had comparable previous CT images obtained without CARE kV or SAFIRE, using the standard dose (i.e., reference mAs of 240) on an identical CT scanner and reconstructed with filtered back projection (FBP) within 1 year. Patients were divided into two groups: group A (33 patients, CT scanned with CARE kV); and group B (44 patients, scanned after reducing the reference mAs from 240 to 170 and applying both CARE kV and SAFIRE). CT number, image noise for four organs and radiation dose were compared among the two groups. Image noise increased after CARE kV application (p < 0.001) and significantly decreased as SAFIRE strength increased (p < 0.001). Image noise with reduced-mAs scan (170 mAs) in group B became similar to that of standard-dose FBP images after applying CARE kV and SAFIRE strengths of 3 or 4 when measured in the aorta, liver or muscle (p ≥ 0.108). Effective doses decreased by 19.4% and 41.3% for groups A and B, respectively (all, p < 0.001) after application of CARE kV with or without SAFIRE. Combining CARE kV, reduction of mAs from 240 to 170 mAs and noise reduction by applying SAFIRE strength 3 or 4 reduced the radiation dose by 41.3% without increasing image noise compared with the standard-dose FBP images.

  12. Application of Low-dose Chest 16-slice Spiral CT Scan in Examination of Foreign Bodies in Bronchi of Children%16层螺旋CT低剂量胸部扫描在小儿气道异物检查中的应用

    Institute of Scientific and Technical Information of China (English)

    曹治婷

    2011-01-01

    目的:探讨16层螺旋CT低剂量胸部扫描在小儿气道异物检查中的应用价值.方法:对48例经纤维支气管镜证实有气道异物的患儿行不同荆量检查,其中28倒为低剂量(30 mAs)扫描,20例为常规(100 mAs)剂量扫描,将轴位薄层原始数据传至工作站分别行多平面重组(MPR)、最小密度投影(MinIP)、容积再现(VR)及CT仿真内镜(CTVE)后处理重建成像、分析其敏感性和准确性.结果:28例低剂量扫描患儿中发现异物27例,诊断准确率为96.4%;20例常规刺量扫描患儿中发现异物20例,诊断准确率为100%.两者无显著性差异(P>0.05).结论:16层螺旋CT低剂量胸部扫描不仅减少小儿接受的辐射剂量,后处理图像重建后可清楚显示异物的部位、形态、大小及阻塞部位,是诊断小儿气道异物无创并实用的检查方法.%Objective To discuss the value of low-dose chest 16-slice spiral CT scan in the examination of foreign hodies in bronchi of children. Methods Forty-eight children with foreign bodies aspiration were scanned transversely and reconstructed in different doses of the line check, twenty-eight were scanned witb low-dose, the others were scanned with conventional dose. Then the original axial data were transferred to workstation for image reconsruction by multi-planar reconstruction (MPR), minimum intensity projection (MinIP), volume rendering (VR) and CT virtual endoscopy (CTVE) respectively. The sensitivity and accuracy were analyzed. Results Twenty-seven cases were diagnosed with foreign bodies in those scanned with low-dose, diagnostic accuracy was 96.4%. Twenty cases were diagnosed with foreign bodies diagnostic accuracy was 100%. The difference was not statistically significant (P>0.05). Conclusion Low-dose chest 16-slice spiral CT scan can not only reduce the radiation dose received but also clearly show the site, the shape and the size of foreign body, and even the position of obstruction after post

  13. Correlation of the CT values of abdominal aorta,renal artery and renal cortex with its thickness on 64-MDCT contrast en-hanced images

    Institute of Scientific and Technical Information of China (English)

    Alomary Mahfooz-Naef; Vikash; Wang Qiu-xia; Zhang Jin-hua; Hu Dao-yu

    2015-01-01

    Objective:To investigate the correlation of abdominal aorta CT value,renal artery CT value and renal cor-tex thickness with renal cortex CT value on contrast enhanced 64-slice CT images.Methods:96 patients (50 men and 46 women;16~74 years)with normal kidney function,which was confirmed by kidney function test were enrolled in this stud-y,including bilateral kidneys of 92 cases and unilateral kidney of 4 cases (total of 188 kidneys;92 left,96 right).After intra-venous (IV)injection of contrast agent the kidneys of the selected patients were scanned by MDCT.The scans were per-formed in arterial,venous and 3min delayed phases.All statistical analyses were performed by using IBM SPSS 20.0.Graphs were generated using Graph Pad Prism 5 software.Quantitative data were presented as mean ± standard deviation,while qualitative data were presented as frequency (%).P<0.05 was considered to be statistically significant.Results:The mean renal cortex thickness was (5.19±0.81)mm in all kidneys.In the arterial phase,a statistically significant positive correla-tion between renal cortex CT values and abdominal aortic CT values was showed (r= 0.584;P<0.001).A statistically sig-nificant positive correlation between renal cortex CT values and renal cortex thickness was demonstrated (r= 0.533,P<0.0001).Likewise,there was a positive correlation between renal cortex CT value and renal artery CT values (r= 0.43,P<0.001).Conclusion:It is a promising approach to assess the individual kidney function by measuring abdominal aorta CT value,renal artery CT value,renal cortex CT value and renal cortex thickness using contrast MDCT.

  14. Abdominal CT during pregnancy: a phantom study on the effect of patient centring on conceptus radiation dose and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Solomou, G.; Damilakis, J. [University of Crete, Faculty of Medicine, Department of Medical Physics, Heraklion, P.O. Box 2208, Crete (Greece); Papadakis, A.E. [University Hospital of Heraklion, Department of Medical Physics, Heraklion, P.O. Box 1352, Crete (Greece)

    2015-04-01

    To investigate the effect of patient centring on conceptus radiation dose and image quality in abdominal CT during pregnancy. Three anthropomorphic phantoms that represent a pregnant woman at the three trimesters of gestation were subjected to a routine abdominal CT. Examinations were performed with fixed mAs (mAs{sub f}) and with the automatic exposure control system (AEC) activated. The percent reduction between mAs{sub f} and modulated mAs (mAs{sub mod}) was calculated. Conceptus dose (D{sub c}) was measured using thermoluminescent dosimeters. To study the effect of misplacement of pregnant women on D{sub c}, each phantom was positioned at various locations relative to gantry isocentre. Image quality was evaluated on the basis of image noise, signal-to-noise ratio, and contrast-to-noise ratio. The maximum reduction between mAs{sub f} and mAs{sub mod} was 59.8 %, while the corresponding D{sub C} reduction was 59.3 %. D{sub C} was found to decrease by up to 25 % and 7.9 % for phantom locations below and above the isocentre, respectively. Image quality deteriorated when AEC was activated, and it was progressively improved from lower to higher than the isocentre locations. Centring errors do not result in an increase in D{sub c}. To maintain image quality, accurate centring is required. (orig.)

  15. Radiation Leukemogenesis at Low Dose Rates

    Energy Technology Data Exchange (ETDEWEB)

    Weil, Michael; Ullrich, Robert

    2013-09-25

    The major goals of this program were to study the efficacy of low dose rate radiation exposures for the induction of acute myeloid leukemia (AML) and to characterize the leukemias that are caused by radiation exposures at low dose rate. An irradiator facility was designed and constructed that allows large numbers of mice to be irradiated at low dose rates for protracted periods (up to their life span). To the best of our knowledge this facility is unique in the US and it was subsequently used to study radioprotectors being developed for radiological defense (PLoS One. 7(3), e33044, 2012) and is currently being used to study the role of genetic background in susceptibility to radiation-induced lung cancer. One result of the irradiation was expected; low dose rate exposures are ineffective in inducing AML. However, another result was completely unexpected; the irradiated mice had a very high incidence of hepatocellular carcinoma (HCC), approximately 50%. It was unexpected because acute exposures are ineffective in increasing HCC incidence above background. This is a potential important finding for setting exposure limits because it supports the concept of an 'inverse dose rate effect' for some tumor types. That is, for the development of some tumor types low dose rate exposures carry greater risks than acute exposures.

  16. LOW DOSE MAGNESIUM SULPHATE REGIME FOR ECLAMPSIA

    Directory of Open Access Journals (Sweden)

    Bangal V

    2009-09-01

    Full Text Available Pre- eclampsia is one of the commonest medical complications seen during pregnancy. It contributes significantly to maternal and perinatal morbidity and mortality. Dr.J.A.Pritchard in 1955, introduced magnesium sulphate for control of convulsions in eclampsia and is used worldwide. Considering the low body mass index of indian women, a low dose magnesium sulphate regime has been introduced by some authors. Present study was carried out at tertiary care centre in rural area. Fifty cases of eclampsia were randomly selected to find out the efficacy of low dose magnesium sulphate regime to control eclamptic convulsions. Maternal and perinatal outcome and magnesium toxicity were analyzed. It was observed that 86% cases responded to initial intravenous dose of 4 grams of 20% magnesium sulphate . Eight percent cases, who got recurrence of convulsion, were controlled by additional 2 grams of 20% magnesium sulphate. Six percent cases required shifting to standard Pritchard regime, as they did not respond to low dose magnesium sulphate regime. The average total dose of magnesium sulphate required for control of convulsions was 20 grams ie. 54.4% less than that of standard Pritchard regime. The maternal and perinatal morbidity and mortality in the present study werecomparable to those of standard Pritchard regime. The study did not find a single case of magnesium related toxicity with low dose magnesium sulphate regime. Low dose magnesium sulphate regime was found to be safe and effective in eclampsia.

  17. CT-guided percutaneous drainage of intra-abdominal abscesses: APACHE III score stratification of 1-year results

    Energy Technology Data Exchange (ETDEWEB)

    Betsch, Angelika; Belka, Claus [Department of Radiation Oncology, Eberhard Karls University, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Wiskirchen, Jakub; Truebenbach, Jochen; Claussen, Claus D.; Duda, Stephan H. [Department of Diagnostic Radiology, Eberhard Karls University, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Manncke, Klaus H. [Department of General Surgery, Eberhard Karls University, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany)

    2002-12-01

    Our objective was to evaluate the clinical success rates of percutaneously drained intra-abdominal abscesses using a risk stratification score for severely ill patients (APACHE III; Acute Physiology, Age, Chronic Health Evaluation). In 75 patients CT-guided percutaneous abscess drainage was performed to treat intra-abdominal abscesses. The clinical success rate based on a 1-year follow-up was correlated with abscess etiology, size, and structure, as well as with the initial APACHE III score. Clinical success, i.e., the complete removal of the abscess without surgical treatment, was observed in 62 of 75 patients (83%). Abscess size (<200 cm{sup 3}) and abscesses with a simple structure correlated with higher clinical success rates. Patients presenting with APACHE III scores below 30 were treated by percutaneous abscess drainages (PAD) alone significantly more often than patients presenting with higher APACHE scores. The percutaneous drainage of intra-abdominal abscesses shows good long-term results as long as abscesses are singular, small (<200 cm{sup 3}), and located in well accessible regions in combination with low APACHE scores (<30). (orig.)

  18. Diagnostic Value of Low Dose Multi-slice Spiral VHRCT (MSCT) CT in Children with Chronic Interstitial Lung Disease%小剂量多层螺旋CT(MSCT)VHRCT在小儿慢性肺间质病变中的诊断价值

    Institute of Scientific and Technical Information of China (English)

    李燕北; 李云秀; 王宝军

    2016-01-01

    目的:分析研讨小剂量多层螺旋CT(MSCT)VHRCT在小儿慢性肺间质病变中的诊断价值。方法:此研究中所研讨的32例患儿均随机从2013年5月至2014年11月期间我院收治的小儿慢性肺间质病变患儿中选取而出,回顾分析患儿临床病历资料,32例患儿均接受小剂量多层螺旋CT(MSCT)容积数据重组高分辨和HRCT扫描,对比此两者检查扫描方式在囊状透亮部位、网格影、结节影、肺大泡影、磨玻璃密度影等差异性,对比诊断准确性和图像质量评分状况。结果:对比同层面囊状透亮部位、网格影、结节影、肺大泡影、磨玻璃密度影、蜂窝影等显影状况,HRCT方式比MSCT方式要稍微高一点,但组间数据无统计学意义(P>0.05)。小剂量MSCT检查方式在图像质量评分上比VHRCT检查方式要稍高,但组间数据无统计学意义(P>0.05);在诊断准确率上,小剂量MSCT(93.75%)和VHRCT方式(96.87%)比较,虽后者稍高,但组间数据无统计学意义(P>0.05)。结论:HRCT检测结果比小剂量多层螺旋CTMSCT检查结果更加具有优势性,特别是针对小剂量多层螺旋CTMSCT和大龄患儿检查判定不佳时,可依据实际状况考虑是否采用HRCT,因此,建议临床在诊断疾病时,按照患儿实际状况确定检查方式,确保诊断准确性。%ABSTRACT:Objective:To analyze and discuss the value of low dose multi-slice spiral VHRCT (MSCT) CT in the diagnosis of chronic interstitial lung disease in children.Methods:32 children with this research studied were randomly from 2013 May to 2014 November period in our hospital pediatric chronic lung interstitial lesion in children with selected out, children with clin-ical data were retrospectively analyzed, 32 cases underwent low dose multislice spiral CT (MSCT) volume number according to the restructuring of high resolution scanning and HRCT, compared with the two scanning way

  19. Energy Limits in Second Generation High-pitch Dual Source CT - Comparison in an Upper Abdominal Phantom

    Directory of Open Access Journals (Sweden)

    Martin Beeres

    2015-01-01

    Full Text Available Objectives: The aim of our study was to find out how much energy is applicable in second-generation dual source high-pitch computed tomography (CT in imaging of the abdomen. Materials and Methods: We examined an upper abdominal phantom using a Somatom Definition Flash CT-Scanner (Siemens, Forchheim, Germany. The study protocol consisted of a scan-series at 100 kV and 120 kV. In each scan series we started with a pitch of 3.2 and reduced it in steps of 0.2, until a pitch of 1.6 was reached. The current was adjusted to the maximum the scanner could achieve. Energy values, image noise, image quality, and radiation exposure were evaluated. Results: For a pitch of 3.2 the maximum applicable current was 142 mAs at 120 kV and in 100 kV the maximum applicable current was 114 mAs. For conventional abdominal imaging, current levels of 200 to 260 mAs are generally used. To achieve similar current levels, we had to decrease the pitch to 1.8 at 100 kV - at this pitch we could perform our imaging at 204 mAs. At a pitch of 2.2 in 120 kV we could apply a current of 206 mAs. Conclusion: We conclude our study by stating that if there is a need for a higher current, we have to reduce the pitch. In a high-pitch dual source CT, we always have to remember where our main focus is, so we can adjust the pitch to the energy we need in the area of the body that has to be imaged, to find answers to the clinical question being raised.

  20. Effect of reducing abdominal compression during prone CT colonography on ascending colonic rotation during supine-to-prone positional change

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jong eon; Park, Seong Ho; Lee, Jong Seok; Kim, Hyun Jin; KIm, Ah Young; Ha, Hyun Kwon [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2016-02-15

    To determine the effect of reduced abdominal compression in prone position on ascending colonic movement during supine-to-prone positional change during CT colonography (CTC). Eighteen consecutive patients who had undergone prone CTC scanning with cushion blocks placed under the chest and hip/thigh to reduce abdominal compression and had confirmed sessile polyps ≥ 6 mm in the well-distended, straight, mid-ascending colon, were included. Radial location along the ascending colonic luminal circumference (°) was measured for 24 polyps and 54 colonic teniae on supine and prone CTC images. The supine-to-prone change ranging between -180° and +180° (- and + for internal and external colonic rotations, respectively), was determined. In addition, possible causes of any ascending colonic rotations were explored. Abdominal compression during prone CTC scanning completely disappeared with the use of cushion blocks in 17 of 18 patients. However, some degrees of ascending colonic rotation were still observed, with the radial location changes of -22° to 61° (median, 13.9°) for the polyps and similar degrees for teniae. Fifty-four percent and 56% of polyps and teniae, respectively, showed changes > 10°. The radial location change of the polyps was significantly associated with the degree of anterior shift of the small bowel and mesentery (r = 0.722, p < 0.001) and the degree of posterior displacement of the ascending colon (r = 0.566, p = 0.004) during supine-to-prone positional change. Ascending colonic rotation upon supine-to-prone positional change during CTC, mostly in the form of external rotation, is not eliminated by removing abdominal compression in prone position.

  1. 低剂量CT灌注成像在康复期缺血性卒中患者中的应用价值%The Application Value of Low Dose CT Perfusion Imaging in Patients with Ischemic Stroke of Convalescence

    Institute of Scientific and Technical Information of China (English)

    付冬

    2016-01-01

    Objective To study the application value of low dose CT perfusion imaging in patients with ischemic stroke of convalescence.Methods One hundred patients with recovery stage of ischemic stroke were selected as object of study from March 2013 to March 2015 in our hospital. According to the stochastic indicator method, the patients were divided into observation group and control group of 50 cases each. in the two groups of patients, on the basis of routine scan control group using conventional dose (120 kv, 200 mvas) CT perfusion imaging, observation group with low doses (80 kv, 200 mvas) CT perfusion imaging. The two groups were measured in patients with cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MMT), time to peak (TTP).Results Compared two groups of patients, significantly lower rCBF of ischemic lesions central area, the difference was statistically significant (P0.05), compared two groups of patients significantly lower rCBV ischemic lesions central area, the difference was statistically significant (P0.05), compared two groups of patients with the same parts of rCBV, there was no statistically significant difference (P>0.05), compared two groups of patients, a significantly lower rCBV ischemic lesions central area, the difference was statistically significant (P0.05)两组患者相比,病灶中心区rCBV明显低于缺血区,差异有统计学意义(P<0.05),不同组别相同部位的rCBV基本一致,差异无统计学意义(P>0.05)两组患者相比,相同部位的rCBV基本一致,差异无统计学意义(P>0.05),两组患者相比,病灶中心区rCBV明显低于缺血区,差异有统计学意义(P<0.05)。结论低剂量CT灌注成像,在有效降低辐射剂量的同时,能够有效评价患者病灶处的血流情况,对临床治疗以及预后恢复具有重要意义。

  2. Tardive dyskinesia with low dose amisulpride.

    Science.gov (United States)

    Tharoor, Hema; Padmavati, R

    2013-01-01

    In recent years, there has been an increasing trend to use amisulpride in the treatment of dysthymia and also as an adjunct treatment in patients with major depression. At low doses (50 mg), amisulpride preferentially blocks presynaptic auto receptors, enhances dopamine release, and therefore acts as a dopaminergic compound able to resolve the dopaminergic hypo activity that characterizes depression. Based on experimental data, amisulpride is the drug of choice for dopaminergic transmission disorders, both in depression and in schizophrenia. This case highlights the development of dyskinesia in a depressed patient treated with low dose amisulpride and fluvoxamine.

  3. Abdominal CT enterography as an imaging tool for chronic diarrhea: Review of technique and diagnostic criteria

    OpenAIRE

    Mona El-Kalioubie; Rasha Ali

    2015-01-01

    Purpose: Our aim was to evaluate the role of multi-slice CT enterography in chronic diarrhea and its degree of correlation with endoscopy and histopathology. Materials and methods: 50 patients with chronic diarrhea (23 Crohn’s disease, 3 ulcerative colitis, 5 Tuberculous enteritis, 1 Entamoeba infestation, 4 Celiac disease, 5 lymphoma and 10 miscellaneous) were evaluated by CT enterography. Quantitative image analysis included evaluation of bowel caliber and wall thickness. Qualitative ana...

  4. AP diameter shows the strongest correlation with CTDI and DLP in abdominal and chest CT.

    LENUS (Irish Health Repository)

    Zarb, Francis

    2010-01-01

    The purpose of this study is to investigate the relationships among cross-sectional diameters, weight and computed tomography (CT) dose descriptors (CTDI and DLP) to identify which is best used as a measure for the establishment of DRLs in CT. Data (gender, weight, cross-sectional diameters, dose descriptors) from 56 adult patients attending for either a CT examination of the abdomen or chest was obtained from two spiral CT units using automatic milliampere modulation. The AP diameter was demonstrated as the main contributing factor influencing the dose in CT (CTDI: r(2) = 0.269, p-value < or =0.001; DLP: r(2) = 0.260, p-value < or =0.001) since it has a greater correlation with radiation dose than body weight and can thus be its substitute in dose-reduction strategies and establishment of DRLs. The advantages of using the AP diameter are that it can easily be measured prior to scanning or retrospectively from previous CT images. However, further studies on the practicality of this approach are recommended.

  5. Low-dose aspirin and rupture ofabdominal aortic aneurysm: A nationwide, population-based study

    DEFF Research Database (Denmark)

    Wemmelund, H.; Jørgensen, T.; Høgh, A.

    OBJECTIVE: The use of low-dose aspirin (acetylsalicylic acid [ASA]) has been suggested to attenuate growth of abdominal aortic aneurysms (AAAs), yet solid clinical evidence of this hypothesis is still missing. This study aimed to investigate whether preadmission ASA use influenced the risk...

  6. A preliminary exploration of low-dose semicoronal CT of the sacroiliac joints in the diagnosis of ankylosing spondylitis%低剂量斜冠状位骶髂关节CT检查诊断强直性脊柱炎的研究初探

    Institute of Scientific and Technical Information of China (English)

    高岱; 李坤鹏; 文琼芳; 朱剑; 张江林; 黄烽

    2016-01-01

    的同时保持较高的图像质量,可以更好地满足AS患者的临床诊断及随访需求.%Objective To evaluate the clinical value of low-dose semicoronal computerized tomography (CT) of sacroiliac joints (SIJ) in the early diagnosis of ankylosing spondylitis (AS).Methods Patients who were diagnosed with AS and had received axial CT examination of SIJs over the past 2 years were recruited.All of them simultaneously underwent a low-dose semicoronal CT of SIJs.The clinical data were recorded.Radiation dose was compared between low-dose CT and the previous conventional axial CT.Image quality of low-dose CT was assessed and correlation between image quality and weight or body mass index (BMI) was analyzed.CT images of the two groups were graded by modified New York criteria, the Lee criteria and the Innsbruck criteria.The kappa coefficient was used to assess the consistency of grading between the two groups.Results Thirty-three patients were enrolled in this study.The effective dose (ED) of semicoronal SIJ CT was 3.37 mSv which was 49% lower than conventional axial CT (6.56 mSv).Lower dose had the potential protection of gonads.The quality of images in male patients with BMI < 25 kg/m2 and all female patients were good or excellent.There was a significant negative correlation between image quality and BMI (r =-0.746, P =0.000;r =-0.784, P =0.000;respectively).All patients were diagnosed as sacroiliitis by modified New York criteria and the grading of two groups was consistent.The consistency of grading between two groups was satisfactory no matter which classification criteria was used.(k =0.897 with Lee criteria;k =0.814