Image Registration for PET/CT and CT Images with Particle Swarm Optimization

International Nuclear Information System (INIS)

Lee, Hak Jae; Kim, Yong Kwon; Lee, Ki Sung; Choi, Jong Hak; Kim, Chang Kyun; Moon, Guk Hyun; Joo, Sung Kwan; Kim, Kyeong Min; Cheon, Gi Jeong

2009-01-01

Image registration is a fundamental task in image processing used to match two or more images. It gives new information to the radiologists by matching images from different modalities. The objective of this study is to develop 2D image registration algorithm for PET/CT and CT images acquired by different systems at different times. We matched two CT images first (one from standalone CT and the other from PET/CT) that contain affluent anatomical information. Then, we geometrically transformed PET image according to the results of transformation parameters calculated by the previous step. We have used Affine transform to match the target and reference images. For the similarity measure, mutual information was explored. Use of particle swarm algorithm optimized the performance by finding the best matched parameter set within a reasonable amount of time. The results show good agreements of the images between PET/CT and CT. We expect the proposed algorithm can be used not only for PET/CT and CT image registration but also for different multi-modality imaging systems such as SPECT/CT, MRI/PET and so on.

16-slice multi-detector row CT coronary angiography: image quality and optimization of the image reconstruction window

International Nuclear Information System (INIS)

Kim, Yoo Kyung; Shim, Sung Shine; Lim, Soo Mee; Hwang, Ji Young; Kim, Yoon Kyung

2005-01-01

The purpose of this experiment is to investigate the image quality of CT coronary angiography using a 16-slice multi-detector row CT and to determine the optimal image reconstruction window. CT coronary angiography was obtained in 36 nonsymptomatic volunteers using a 16-slice multi-detector row CT (SOMATOM Sensation, Siemens Medical System). The mean heart rates were 70 beats per minute (bpm) or less in 18 persons and more than 70 bpm in 18 persons. Eleven data sets were obtained for each patient (reconstructed at 30%-80% of the cardiac cycle with an increment of 5%). Image quality of the eight coronary segments [left main coronary artery (LM), proximal and middle segments of left anterior descending artery (p-LAD, m-LAN) and left circumflex coronary artery (p-LCx, m-LCx) and proximal, middle and distal segments of right coronary artery (p-RCA, m-RCA, d-RCA)] was assessed. The optimal reconstruction windows in the cardiac cycle for the best image quality were 60-70% for the segments of the LM, LAD, and LC arteries in two groups (bpm 70) and 55-65% (bpm 70) for the segments of the RCA. On the best dataset for each coronary segment, the following diagnostic image quality was achieved in the two groups: LM: 100%, 83%; p-LAD: 100%, 88% m-LAD: 100%, 72%; p-LCx: 100%, 72%; m-LCx: 100%, 72%; p-RCA: 94%, 72%; m-RCA: 61%, 50%; d-RCA: 100%, 80%. The 16 slice multi-detector row CT scan provided visualization of the coronary arteries with high resolution. Especially in the group with a mean heart rate of 70 bpm or less, all the coronary segments except the RCA showed diagnostic image quality. Optimal image quality was achieved with a 60-70% trigger delay for all coronary arterial segments, but the best images of RCA were achieved in the earlier cardiac phase in the patients with a mean heart rate of more than 70 bpm

Multi-slice and dual-source CT in cardiac imaging. Principles - protocols - indications - outlook. 2. ed.

International Nuclear Information System (INIS)

Ohnesorge, B.M.; Flohr, T.G.; Becker, C.R.; Reiser, M.F.; Knez, A

2007-01-01

Cardiac diseases, and in particular coronary artery disease, are the leading cause of death and morbidity in industrialized countries. The development of non-invasive imaging techniques for the heart and the coronary arteries has been considered a key element in improving patient care. A breakthrough in cardiac imaging using CT occurred in 1998, with the introduction of multi-slice computed tomography (CT). Since then, amazing advances in performance have taken place with scanners that acquire up to 64 slices per rotation. This book discusses the state-of-the-art developments in multi-slice CT for cardiac imaging as well as those that can be anticipated in the future. It serves as a comprehensive work that covers all aspects of this technology, from the technical fundamentals and image evaluation all the way to clinical indications and protocol recommendations. This fully reworked second edition draws on the most recent clinical experience obtained with 16- and 64-slice CT scanners by world-leading experts from Europe and the United States. It also includes ''hands-on'' experience in the form of 10 representative clinical case studies, which are included on the accompanying CD. As a further highlight, the latest results of the very recently introduced dual-source CT, which may soon represent the CT technology of choice for cardiac applications, are presented. This book will not only convince the reader that multi-slice cardiac CT has arrived in clinical practice, it will also make a significant contribution to the education of radiologists, cardiologists, technologists, and physicists-whether newcomers, experienced users, or researchers. (orig.)

The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients

DEFF Research Database (Denmark)

Nielsen, Marie Kristina Rue; Chakera, Annette H; Hesse, Birger

2011-01-01

The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients.......The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients....

Multi-level tree analysis of pulmonary artery/vein trees in non-contrast CT images

Science.gov (United States)

Gao, Zhiyun; Grout, Randall W.; Hoffman, Eric A.; Saha, Punam K.

2012-02-01

Diseases like pulmonary embolism and pulmonary hypertension are associated with vascular dystrophy. Identifying such pulmonary artery/vein (A/V) tree dystrophy in terms of quantitative measures via CT imaging significantly facilitates early detection of disease or a treatment monitoring process. A tree structure, consisting of nodes and connected arcs, linked to the volumetric representation allows multi-level geometric and volumetric analysis of A/V trees. Here, a new theory and method is presented to generate multi-level A/V tree representation of volumetric data and to compute quantitative measures of A/V tree geometry and topology at various tree hierarchies. The new method is primarily designed on arc skeleton computation followed by a tree construction based topologic and geometric analysis of the skeleton. The method starts with a volumetric A/V representation as input and generates its topologic and multi-level volumetric tree representations long with different multi-level morphometric measures. A new recursive merging and pruning algorithms are introduced to detect bad junctions and noisy branches often associated with digital geometric and topologic analysis. Also, a new notion of shortest axial path is introduced to improve the skeletal arc joining two junctions. The accuracy of the multi-level tree analysis algorithm has been evaluated using computer generated phantoms and pulmonary CT images of a pig vessel cast phantom while the reproducibility of method is evaluated using multi-user A/V separation of in vivo contrast-enhanced CT images of a pig lung at different respiratory volumes.

Multi-detector CT knee arthrography - initial experience

International Nuclear Information System (INIS)

Thomson, J.M.Z.; Fallon, M.; Breidahl, W.H.

2002-01-01

Full text: Traditional plain film arthrography can achieve reasonable accuracy and is an accepted method of investigation of patients with knee pain and possible meniscal tear. Multi-detector CT can potentially provide a more detailed and accurate examination due to its high-resolution crosssectional and multi-planar capabilities. The aim of this study was to assess the accuracy of our technique. All patients who underwent a multi-detector CT knee arthrogram in an initial 8 month period were identified. Initially the referring clinician was contacted. If the patient was referred to an orthopaedic surgeon the outcome of orthopaedic review was recorded using clinical, arthroscopic and / or MRI follow-up of the patient population. One hundred and twelve patients had a Multi-detector CT knee arthrogram performed within and 8 month period. Follow-up information was received in 69.7% of patients. Of these 68.9% had orthopaedic assessment - of which 69.2% underwent a knee arthroscopy.There was total agreement of findings in 67%, agreement of meniscal findings in 67% and chondral findings in 100%. Overall, orthopaedic opinion agreed with CT findings in 76.9%. At this stage, all meniscal tears not described in the initial CT arthrogram report have in retrospect been visible. Multi-detector CT knee arthrography is an accurate and elegant technique for investigation of knee pain, providing information in a format familiar to those reporting knee MRI. There is an initial learning curve. The technique is particularly useful in chondral assessment. It is accurate for meniscal pathology, although caution and recognition of potential pitfalls is required. Copyright (2002) Blackwell Science Pty Ltd

Benign versus malignant osseous lesions in spine: differentiation by means of bone SPECT/CT fused image

International Nuclear Information System (INIS)

Yao Zhiming; Qu Wanying

2004-01-01

This study compared the efficiency of SPECT-CT fused image with planar bone scan, bone SPECT and CT in differentiating malignant from benign lesions and detecting metastases to the spine. Methods. Total 144 patients with spinal lesions underwent planar bone scan (WB), single photon tomography (SPECT), CT and SPECT-CT fused image by a SPECT/CT system. The malignant or benign nature of lesions was proved by radiological Methods, histological findings, 6-24 month follow-up, or all of these. The diagnostic results was divided into 4 types, i.e., normal, benign, doubtful malignant and malignant. Results. There were 137 malignant and 252 benign lesions in 144 patients, respectively. The percentages of doubtful malignant diagnosed by WB, SPECT, CT and fused image are 22.6%, 5.1%, 9.5% and 0%, respectively, p < 0.01-0.001, except for the comparison between the percentages of SPECT and CT. Sensitivities in detection of malignant lesions by WB, SPECT, CT and fused image are 75.2%, 94.2%, 96.6% and 99.3%, respectively, P < 0.001, excepting for the comparisons between those of SPECT and CT, and between those of CT and fused image. The sensitivities m detection of benign lesions by WB, SPECT, CT and fused image are, 56.7%, 86.5%, 90.1% and 96.8%, respectively, P < 0.005 - 0.001, excepting for the comparison between those of SPECT and CT. The specificities in detection of maliganant lesions by WB, SPECT, CT and fused image are 70.6%, 88.9%, 97.2% and 97.6%, respectively, P < 0.001, excepting for the comparison between those of CT and fused image. Conclusion. Bone SPECT-CT fused image has highest diagnostic and differentiating diagnostic values in detection of spinal abnormalities over the planar bone scanning and SPECT. The CT by present SPECT/CT system can complement planar bone scanning and SPECT and is clinically valuable in detection of spinal abnormalities. (authors)

Usefulness of multi-plane dynamic subtraction CT (MPDS-CT) for intracranial high density lesions

Energy Technology Data Exchange (ETDEWEB)

Takagi, Ryo; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan)

1996-02-01

We present a new CT technique using the high speed CT scanner in detection and evaluation of temporal and spatial contrast enhancement of intracranial high density lesions. A multi-plane dynamic subtraction CT (MPDS-CT) was performed in 21 patients with intracranial high density lesions. These lesions consisted of 10 brain tumors, 7 intracerebral hemorrhages and 4 vascular malformations (2 untreated, 2 post-embolization). Baseline study was first performed, and 5 sequential planes of covering total high density lesions were selected. After obtaining the 5 sequential CT images as mask images, three series of multi-plane dynamic CT were performed for the same 5 planes with an intravenous bolus injection of contrast medium. MPDS-CT images were reconstructed by subtracting dynamic CT images from the mask ones. MPDS-CT were compared with conventional contrast-enhanced CT. MPDS-CT images showed the definite contrast enhancement of high density brain tumors and vascular malformations which were not clearly identified on conventional contrast-enhanced CT images because of calcified or hemorrhagic lesions and embolic materials, enabling us to eliminate enhanced abnormalities with non-enhanced areas such as unusual intracerebral hemorrhages. MPDS-CT will provide us further accurate and objective information and will be greatly helpful for interpreting pathophysiologic condition. (author).

Comparison of positron emission tomography/CT and bremsstrahlung imaging following Y-90 radiation synovectomy

International Nuclear Information System (INIS)

Barber, Thomas W.; Yap, Kenneth S.K.; Cherk, Martin H.; Kalff, Victor; Powell, Anne

2013-01-01

The aim of this study is to compare the results of positron emission tomography (PET)/CT with bremsstrahlung imaging following Y-90 radiation synovectomy. All patients referred to our institution for Y-90 radiation synovectomy between July 2011 and February 2012 underwent both PET/CT and bremsstrahlung planar (±single photon emission computed tomography (SPECT) or SPECT/CT) imaging at 4 or 24 h following administration of Y-90 silicate colloid. PET image acquisition was performed for between 15 and 20min. In patients who underwent SPECT, side-by-side comparison with PET was performed and image quality/resolution scored using a five-point scale. The distribution pattern of Y-90 on PET and bremsstrahlung imaging was compared with the intra- or extra-articular location of Y-90 activity on fused PET/CT. Thirteen joints (11 knees and two ankles) were imaged with both PET/CT and planar bremsstrahlung imaging with 12 joints also imaged with bremsstrahlung SPECT. Of the 12 joints imaged with SPECT, PET image quality/resolution was superior in 11 and inferior in one. PET demonstrated a concordant distribution pattern compared with bremsstrahlung imaging in all scans, with the pattern classified as diffuse in 12 and predominantly focal in one. In all 12 diffuse scans, PET/CT confirmed the Y-90 activity to be located intra-articularly. In the one predominantly focal scan, the fused PET/CT images localised the Y-90 activity to mostly lie in the extra-articular space of the knee. PET/CT can provide superior image quality compared with bremsstrahlung imaging and may enable reliable detection of extra-articular Y-90 activity when there are focal patterns on planar bremsstrahlung imaging.

Characteristics of a multi-image camera on a CT image

International Nuclear Information System (INIS)

Mihara, Kazuhiro; Fujino, Tatsuo; Abe, Katsuhito

1984-01-01

A multi-imaging camera was used for obtaining a hard-copy image from an imaging device of a CT scanner. The contrast and brightness of the CRT and time exposure of the camera were the three important factors which influenced the quality of the hard-copy image. Two kinds of original test patterns were designed to examine the characteristics of the factors. One was the grayscale test pattern which was used to obtain the density curve. This curve, named the Film-CRT curve, (F-C curve) is to distinguish it from the H D curve. The other was the sharpness test pattern which was used to examine the relationship between brightness and sharpness. As a result, the slope of F-C curve became steeper with a decrease in brightness, with an increase in contrast and with increase in exposure time. Sharpness became worse with an increase in brightness. Therefore, to obtain a good hard copy image, the brightness must be set as dark as possible, and the contrast and exposure time must be controlled after due consideration is given to their characteristics. (author)

Comparison of CT numbers between cone-beam CT and multi-detector CT

International Nuclear Information System (INIS)

Kim, Dong Soo; Han, Won Jeong; Kim, Eun Kyung

2010-01-01

To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, ρ(g/cm 3 ), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were ρ=0.001 H+1.07 with R2 value of 0.999 for Somatom Emotion, ρ=0.002 H+1.09 with R2 value of 0.991 for Alphard VEGA, ρ=0.001 H+1.43 with R2 value of 0.980 for i-CAT and ρ=0.001 H+1.30 with R2 value of 0.975 for Implagraphy. CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

Comparison of CT numbers between cone-beam CT and multi-detector CT

Energy Technology Data Exchange (ETDEWEB)

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

2010-06-15

To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, {rho}(g/cm{sup 3}), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were {rho}=0.001 H+1.07 with R2 value of 0.999 for Somatom Emotion, {rho}=0.002 H+1.09 with R2 value of 0.991 for Alphard VEGA, {rho}=0.001 H+1.43 with R2 value of 0.980 for i-CAT and {rho}=0.001 H+1.30 with R2 value of 0.975 for Implagraphy. CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

Multi-projector auto-calibration and placement optimization for non-planar surfaces

Science.gov (United States)

Li, Dong; Xie, Jinghui; Zhao, Lu; Zhou, Lijing; Weng, Dongdong

2015-10-01

Non-planar projection has been widely applied in virtual reality and digital entertainment and exhibitions because of its flexible layout and immersive display effects. Compared with planar projection, a non-planar projection is more difficult to achieve because projector calibration and image distortion correction are difficult processes. This paper uses a cylindrical screen as an example to present a new method for automatically calibrating a multi-projector system in a non-planar environment without using 3D reconstruction. This method corrects the geometric calibration error caused by the screen's manufactured imperfections, such as an undulating surface or a slant in the vertical plane. In addition, based on actual projection demand, this paper presents the overall performance evaluation criteria for the multi-projector system. According to these criteria, we determined the optimal placement for the projectors. This method also extends to surfaces that can be parameterized, such as spheres, ellipsoids, and paraboloids, and demonstrates a broad applicability.

Computer-aided diagnosis workstation and database system for chest diagnosis based on multi-helical CT images

Science.gov (United States)

Satoh, Hitoshi; Niki, Noboru; Mori, Kiyoshi; Eguchi, Kenji; Kaneko, Masahiro; Kakinuma, Ryutarou; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru; Sasagawa, Michizou

2006-03-01

Multi-helical CT scanner advanced remarkably at the speed at which the chest CT images were acquired for mass screening. Mass screening based on multi-helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images and a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification. We also have developed electronic medical recording system and prototype internet system for the community health in two or more regions by using the Virtual Private Network router and Biometric fingerprint authentication system and Biometric face authentication system for safety of medical information. Based on these diagnostic assistance methods, we have now developed a new computer-aided workstation and database that can display suspected lesions three-dimensionally in a short time. This paper describes basic studies that have been conducted to evaluate this new system. The results of this study indicate that our computer-aided diagnosis workstation and network system can increase diagnostic speed, diagnostic accuracy and safety of medical information.

Usefulness of multiplanar reformatted images of multi-detector row helical CT in assessment of biliary stent patency

International Nuclear Information System (INIS)

Kim, Soo Jin; Kim, Suk; Kim, Chang Won; Lee, Jun Woo; Lee, Tae Hong; Choo, Ki Seok; Koo, Young Baek; Moon, Tae Yong; Lee, Suk Hong

2004-01-01

To evaluate the usefulness of multi-detector row helical CT (MDCT), multiplanar reformatted images for the noninvasive assessment of biliary stent patency, and for the planning for management in patients with a sele-expandable metallic stent due to malignant biliary obstruction. Among 90 consecutive patients, from August 1999 to July 2003, 26 cases in 23 patients with malignant biliary obstruction who underwent self-expandable metaIlic stent insertion in the biliary system and percutaneous transhepatic biliary drainage within 7 days after CT were enrolled in this study. On CT images, the complete and functional obstruction of the stent and the precise level of obstruction were evaluated. The presence of an enhancing intraluminal mass or wall thickening around stent was determined, and the causes of obstruction were evaluated. These findings were then compared with percutaneous transhepatic cholangiography. Multi-detector row helical CT correctly demonstrated the patency of a stent in 24 cases (92.3%). It was adequate in helping to depict the precise level of stent occlusion in 23 cases (88.5%). Multi-detector row helical CT also revealed the extent of tumor that represented as an enhancing intraluminal mass or wall thickening around the stent in 23 cases, and this was represented as complete obstruction on percutaneous transhepatic cholangiography. In the case of functional obstruction, MDCT predicted the possible cause of the obstruction. Multiplanar reformatted images of multi-detector row helical CT is a useful imaging modality for the noninvasive assessment of stent patency and the precise level of obstruction when stent obstruction is suspected in the patients with self-expandable metallic stent due to malignant biliary obstruction. It can also predict the possible cause of the obstruction and allows adequate planning for the medical management of such cases

Usefulness of multiplanar reformatted images of multi-detector row helical CT in assessment of biliary stent patency

Energy Technology Data Exchange (ETDEWEB)

Kim, Soo Jin; Kim, Suk; Kim, Chang Won; Lee, Jun Woo; Lee, Tae Hong; Choo, Ki Seok; Koo, Young Baek; Moon, Tae Yong; Lee, Suk Hong [Pusan National Univ. Hospital, Busan (Korea, Republic of)

2004-08-01

To evaluate the usefulness of multi-detector row helical CT (MDCT), multiplanar reformatted images for the noninvasive assessment of biliary stent patency, and for the planning for management in patients with a sele-expandable metallic stent due to malignant biliary obstruction. Among 90 consecutive patients, from August 1999 to July 2003, 26 cases in 23 patients with malignant biliary obstruction who underwent self-expandable metaIlic stent insertion in the biliary system and percutaneous transhepatic biliary drainage within 7 days after CT were enrolled in this study. On CT images, the complete and functional obstruction of the stent and the precise level of obstruction were evaluated. The presence of an enhancing intraluminal mass or wall thickening around stent was determined, and the causes of obstruction were evaluated. These findings were then compared with percutaneous transhepatic cholangiography. Multi-detector row helical CT correctly demonstrated the patency of a stent in 24 cases (92.3%). It was adequate in helping to depict the precise level of stent occlusion in 23 cases (88.5%). Multi-detector row helical CT also revealed the extent of tumor that represented as an enhancing intraluminal mass or wall thickening around the stent in 23 cases, and this was represented as complete obstruction on percutaneous transhepatic cholangiography. In the case of functional obstruction, MDCT predicted the possible cause of the obstruction. Multiplanar reformatted images of multi-detector row helical CT is a useful imaging modality for the noninvasive assessment of stent patency and the precise level of obstruction when stent obstruction is suspected in the patients with self-expandable metallic stent due to malignant biliary obstruction. It can also predict the possible cause of the obstruction and allows adequate planning for the medical management of such cases.

Evaluation of classification method of lung lobe for multi-slice CT images

International Nuclear Information System (INIS)

Sakurai, Kousuke; Matsuhiro, Mikio; Saita, Shinsuke

2010-01-01

Recently, due to the introduction of multi-slice CT, to obtain a high resolution 3D CT image is possible in a short time. The temporal and spatial resolutions are high, so a highly accurate 3D image analysis is possible. To develop a structure analysis of the lung is needed and to be used as a fundamental technology for early detection of the disease. By separating the lung into lung lobes may provide important information for analysis, diagnosis and treatment of lung diseases. Therefore in this report, we adapt to abnormality example with the classification algorithms using the anatomical information of the bronchus, the pulmonary vein and interlobar fissure information, we evaluate the classification. (author)

Incremental value of 99mTc-HYNIC-TOC SPECT/CT over whole-body planar scintigraphy and SPECT in patients with neuroendocrine tumours.

Science.gov (United States)

Trogrlic, Mate; Težak, Stanko

2017-06-12

The aim of this study was to evaluate the additional value of 99m Tc-HYNIC-TOC SPECT/CT over planar whole-body (WB) scintigraphy and SPECT alone in the detection and accurate localisation of neuroendocrine tumour (NET) lesions. This study included 65 patients with a definitive histological diagnosis of NET prior to scintigraphy. Planar WB scintigraphy, SPECT, and SPECT/CT images were acquired at 4 h post-administration of 670 MBq 99m Tc-HYNIC-TOC. Additional SPECT images at 10 min after tracer administration were also acquired. Clinical and imaging follow-up findings were considered as the reference standards (minimum follow-up period, 15 months). Patient and lesion-based analyses of the efficacies of the imaging modalities were performed. While 38 patients exhibited metastasis of NETs, 27 presented no evidence of metastasis. Upon patient-based analysis, the sensitivity and specificity of SPECT/CT were found to be 88.9 and 79.3 %, respectively. The diagnostic accuracies of WB scintigraphy, 4h-SPECT, and SPECT/CT were 72.3, 73.8, and 84.6 %, respectively. The area under curve (AUC) value for SPECT/CT (0.84) was the highest, followed by those for 4h-SPECT (0.75) and WB scintigraphy (0.74). The accuracy and AUC values of SPECT/CT were significantly better compared to those of WB scintigraphy (p < 0.001), 10 min-SPECT (p < 0.001), and 4 h-SPECT (p = 0.001). The findings of SPECT/CT led to the change in treatment plan of 11 patients (16.9 %). The sensitivity and diagnostic accuracy of SPECT/CT in the evaluation of NET lesions outperforms planar WB imaging or SPECT alone.

Estimation of Setup Uncertainty Using Planar and MVCT Imaging for Gynecologic Malignancies

International Nuclear Information System (INIS)

Santanam, Lakshmi; Esthappan, Jacqueline; Mutic, Sasa; Klein, Eric E.; Goddu, S. Murty; Chaudhari, Summer; Wahab, Sasha; El Naqa, Issam M.; Low, Daniel A.; Grigsby, Perry W.

2008-01-01

Purpose: This prospective study investigates gynecologic malignancy online treatment setup error corrections using planar kilovoltage/megavoltage (KV/MV) imaging and helical MV computed tomography (MVCT) imaging. Methods and Materials: Twenty patients were divided into two groups. The first group (10 patients) was imaged and treated using a conventional linear accelerator (LINAC) with image-guidance capabilities, whereas the second group (10 patients) was treated using tomotherapy with MVCT capabilities. Patients treated on the LINAC underwent planar KV and portal MV imaging and a two-dimensional image registration algorithm was used to match these images to digitally reconstructed radiographs (DRRs). Patients that were treated using tomotherapy underwent MVCT imaging, and a three-dimensional image registration algorithm was used to match planning CT to MVCT images. Subsequent repositioning shifts were applied before each treatment and recorded for further analysis. To assess intrafraction motion, 5 of the 10 patients treated on the LINAC underwent posttreatment planar imaging and DRR matching. Based on these data, patient position uncertainties along with estimated margins based on well-known recipes were determined. Results: The errors associated with patient positioning ranged from 0.13 cm to 0.38 cm, for patients imaged on LINAC and 0.13 cm to 0.48 cm for patients imaged on tomotherapy. Our institutional clinical target volume-PTV margin value of 0.7 cm lies inside the confidence interval of the margins established using both planar and MVCT imaging. Conclusion: Use of high-quality daily planar imaging, volumetric MVCT imaging, and setup corrections yields excellent setup accuracy and can help reduce margins for the external beam treatment of gynecologic malignancies

A comparative study of planar, SPECT, x-ray CT and angiographic imaging in the detectability of space occupying lesion (SOL) of liver

International Nuclear Information System (INIS)

Manabe, Takao; Oda, Junro; Kamino, Toshio

1986-01-01

Planar, SPECT, X-CT, and angiography were compared in 47 patients with suspected SOL in the liver. SPECT had greater sensitivity and specificity in detecting SOLs than planar. Especially the detection of SOL less than 3 cm was improved, and the smallest SOL detected by SPECT was 1.0 cm in diameter. SPECT appears reliable procedure for screening SOLs in the liver. Compared with X-CT, SPECT had nearly equal sensitivity in detecting SOLs more than 3 cm, and X-CT had higher sensitivity in detecting SOLs less than 3 cm. But in some cases, for example isodensity SOL, SPECT could detect the SOL which was missed by X-CT. (author)

Multi-material decomposition of spectral CT images

Science.gov (United States)

Mendonça, Paulo R. S.; Bhotika, Rahul; Maddah, Mahnaz; Thomsen, Brian; Dutta, Sandeep; Licato, Paul E.; Joshi, Mukta C.

2010-04-01

Spectral Computed Tomography (Spectral CT), and in particular fast kVp switching dual-energy computed tomography, is an imaging modality that extends the capabilities of conventional computed tomography (CT). Spectral CT enables the estimation of the full linear attenuation curve of the imaged subject at each voxel in the CT volume, instead of a scalar image in Hounsfield units. Because the space of linear attenuation curves in the energy ranges of medical applications can be accurately described through a two-dimensional manifold, this decomposition procedure would be, in principle, limited to two materials. This paper describes an algorithm that overcomes this limitation, allowing for the estimation of N-tuples of material-decomposed images. The algorithm works by assuming that the mixing of substances and tissue types in the human body has the physicochemical properties of an ideal solution, which yields a model for the density of the imaged material mix. Under this model the mass attenuation curve of each voxel in the image can be estimated, immediately resulting in a material-decomposed image triplet. Decomposition into an arbitrary number of pre-selected materials can be achieved by automatically selecting adequate triplets from an application-specific material library. The decomposition is expressed in terms of the volume fractions of each constituent material in the mix; this provides for a straightforward, physically meaningful interpretation of the data. One important application of this technique is in the digital removal of contrast agent from a dual-energy exam, producing a virtual nonenhanced image, as well as in the quantification of the concentration of contrast observed in a targeted region, thus providing an accurate measure of tissue perfusion.

Ring artifact correction for high-resolution micro CT

International Nuclear Information System (INIS)

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

2009-01-01

In high-resolution micro CT using flat detectors (FD), imperfect or defect detector elements may cause concentric-ring artifacts due to their continuous over- or underestimation of attenuation values, which often disturb image quality. We here present a dedicated image-based ring artifact correction method for high-resolution micro CT, based on median filtering of the reconstructed image and working on a transformed version of the reconstructed images in polar coordinates. This post-processing method reduced ring artifacts in the reconstructed images and improved image quality for phantom and in in vivo scans. Noise and artifacts were reduced both in transversal and in multi-planar reformations along the longitudinal axis. (note)

Improved quantitation and reproducibility in multi-PET/CT lung studies by combining CT information.

Science.gov (United States)

Holman, Beverley F; Cuplov, Vesna; Millner, Lynn; Endozo, Raymond; Maher, Toby M; Groves, Ashley M; Hutton, Brian F; Thielemans, Kris

2018-06-05

Matched attenuation maps are vital for obtaining accurate and reproducible kinetic and static parameter estimates from PET data. With increased interest in PET/CT imaging of diffuse lung diseases for assessing disease progression and treatment effectiveness, understanding the extent of the effect of respiratory motion and establishing methods for correction are becoming more important. In a previous study, we have shown that using the wrong attenuation map leads to large errors due to density mismatches in the lung, especially in dynamic PET scans. Here, we extend this work to the case where the study is sub-divided into several scans, e.g. for patient comfort, each with its own CT (cine-CT and 'snap shot' CT). A method to combine multi-CT information into a combined-CT has then been developed, which averages the CT information from each study section to produce composite CT images with the lung density more representative of that in the PET data. This combined-CT was applied to nine patients with idiopathic pulmonary fibrosis, imaged with dynamic 18 F-FDG PET/CT to determine the improvement in the precision of the parameter estimates. Using XCAT simulations, errors in the influx rate constant were found to be as high as 60% in multi-PET/CT studies. Analysis of patient data identified displacements between study sections in the time activity curves, which led to an average standard error in the estimates of the influx rate constant of 53% with conventional methods. This reduced to within 5% after use of combined-CTs for attenuation correction of the study sections. Use of combined-CTs to reconstruct the sections of a multi-PET/CT study, as opposed to using the individually acquired CTs at each study stage, produces more precise parameter estimates and may improve discrimination between diseased and normal lung.

Usefulness of multidetector-row CT (MDCT) for the diagnosis of non-occlusive mesenteric ischemia (NOMI): Assessment of morphology and diameter of the superior mesenteric artery (SMA) on multi-planar reconstructed (MPR) images

International Nuclear Information System (INIS)

Woodhams, Reiko; Nishimaki, Hiroshi; Fujii, Kaoru; Kakita, Satoko; Hayakawa, Kazushige

2010-01-01

Objective: The purpose of this study was to assess the efficacy of multidetector-row CT (MDCT) for the diagnosis of non-occlusive mesenteric ischemia (NOMI) by analyzing morphology and diameter of superior mesenteric artery (SMA). We assessed whether MDCT was as useful as angiography for the diagnosis of NOMI. Materials and methods: Four patients who were diagnosed with NOMI were retrospectively analyzed. All patients had 8-row MDCT followed by laparotomy. Two of them underwent angiography after MDCT. The morphology and diameter of SMA of these cases was analyzed on multi-planar reconstructed (MPR) images. The mean diameter of SMA of NOMI cases was compared to that of 13 control cases. Results: MPR images of all NOMI cases showed irregular narrowing of the SMA, spasm of the arcades of SMA, and poor demonstration of intramural vessels. MPR images of two patients who had angiography were concordant with their angiograms. The mean diameter of SMA of NOMI patients was 3.4 ± 1.1 mm, which was statistically smaller than that of 13 control patients, 6.0 ± 1.5 mm (P < 0.05, Wilcoxon rank sum tests). Conclusion: Angiography has been recognized essential for the diagnosis of NOMI. This study shows the possibility of MDCT to be an equivalently useful modality compared to angiography for the diagnosis of NOMI by interpreting morphologic appearance and diameter of SMA. Introduction of MDCT in the decision tree of NOMI treatment may bring the benefit of prompt diagnosis and subsequent early and efficient initiation of therapy, which may improve the mortality.

Diagnostic role of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for early and atypical bone metastases.

Science.gov (United States)

Chen, Xiao-Liang; Li, Qian; Cao, Lin; Jiang, Shi-Xi

2014-01-01

The bone metastasis appeared early before the bone imaging for most of the above patients. (99)Tc(m)-MDP ((99)Tc(m) marked methylene diphosphonate) bone imaging could diagnosis the bone metastasis with highly sensitivity, but with lower specificity. The aim of this study is to explore the diagnostic value of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for the early period atypical bone metastases. 15 to 30 mCi (99)Tc(m)-MDP was intravenously injected to the 34 malignant patients diagnosed as doubtful early bone metastases. SPECT, CT and SPECT/CT images were captured and analyzed consequently. For the patients diagnosed as early period atypical bone metastases by SPECT/CT, combining the SPECT/CT and MRI together as the SPECT/MRI integrated image. The obtained SPECT/MRI image was analyzed and compared with the pathogenic results of patients. The results indicated that 34 early period doubtful metastatic focus, including 34 SPECT positive focus, 17 focus without special changes by using CT method, 11 bone metastases focus by using SPECT/CT method, 23 doubtful bone metastases focus, 8 doubtful bone metastases focus, 14 doubtful bone metastases focus and 2 focus without clear image. Totally, SPECT/CT combined with SPECT/MRI method diagnosed 30 bone metastatic focus and 4 doubtfully metastatic focus. In conclusion, (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging shows a higher diagnostic value for the early period bone metastases, which also enhances the diagnostic accuracy rate.

Scanning and contrast enhancement protocols for multi-slice CT in evaluation of the upper abdomen

International Nuclear Information System (INIS)

Awai, Kazuo; Onishi, Hiromitsu; Takada, Koichi; Yamaguchi, Yasuo; Eguchi, Nobuko; Hiraishi, Kumiko; Hori, Shinichi

2000-01-01

The advent of multi-slice CT is one of the quantum leaps in computed tomography since the introduction of helical CT. Multi-slice CT can rapidly scan a large longitudinal (z-axis) volume with high longitudinal resolution and low image artifacts. The rapid volume coverage speed of multi-slice CT can increase the difficulty in optimizing the delay time between the beginning of contrast material injection and the acquisition of images and we need accurate knowledge about optimal temporal window for adequate contrast enhancement. High z-axis resolution of multi-slice can improve the quality of three-dimensional images and MPR images and we must select adequate slice thickness and slice intervals in each case. We discuss basic considerations for adequate contrast enhancement and scanning protocols by multi-slice CT scanner in the upper abdomen. (author)

SPECT/CT imaging in general orthopedic practice.

Science.gov (United States)

Scharf, Stephen

2009-09-01

The availability of hybrid devices that combine the latest single-photon emission computed tomography (SPECT) imaging technology with multislice computed tomography (CT) scanning has allowed us to detect subtle, nonspecific abnormalities on bone scans and interpret them as specific focal areas of pathology. Abnormalities in the spine can be separated into those caused by pars fractures, facet joint arthritis, or osteophyte formation on vertebral bodies. Compression fractures can be distinguished from severe degenerative disease, both of which can cause intense activity across the spine on either planar or SPECT imaging. Localizing activity in patients who have had spinal fusion can provide tremendous insight into the causes of therapeutic failures. Infections of the spine now can be diagnosed with gallium SPECT/CT, despite the fact that gallium has long been abandoned because of its failure to detect spine infection on either planar or SPECT imaging. Small focal abnormalities in the feet and ankles can be localized well enough to make specific orthopedic diagnoses on the basis of their location. Moreover, when radiographic imaging provides equivocal or inadequate information, SPECT/CT can provide a road map for further diagnostic studies and has been invaluable in planning surgery. Our ability to localize activity within a bone or at an articular surface has allowed us to distinguish between fractures and joint disease. Increased activity associated with congenital anomalies, such as tarsal coalition and Bertolotti's syndrome have allowed us to understand the pathophysiology of these conditions, to confirm them as the cause of the patient's symptoms, and to provide information that is useful in determining appropriate clinical management. As our experience broadens, SPECT/CT will undoubtedly become an important tool in the evaluation and management of a wider variety of orthopedic patients.

Evaluation of Rib Fractures on a Single-in-plane Image Reformation of the Rib Cage in CT Examinations.

Science.gov (United States)

Dankerl, Peter; Seuss, Hannes; Ellmann, Stephan; Cavallaro, Alexander; Uder, Michael; Hammon, Matthias

2017-02-01

This study aimed to evaluate the diagnostic performance of using a reformatted single-in-plane image reformation of the rib cage for the detection of rib fractures in computed tomography (CT) examinations, employing different levels of radiological experience. We retrospectively evaluated 10 consecutive patients with and 10 patients without rib fractures, whose CT scans were reformatted to a single-in-plane image reformation of the rib cage. Eight readers (two radiologists, two residents in radiology, and four interns) independently evaluated the images for the presence of rib fractures using a reformatted single-in-plane image and a multi-planar image reformation. The time limit was 30 seconds for each read. A consensus of two radiologist readings was considered as the reference standard. Diagnostic performance (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) was assessed and evaluated per rib and per location (anterior, lateral, posterior). To determine the time limit, we prospectively analyzed the average time it took radiologists to assess the rib cage, in a bone window setting, in 50 routine CT examinations. McNemar test was used to compare the diagnostic performances. Single image reformation was successful in all 20 patients. The sensitivity, specificity, PPV, and NPV for the detection of rib fractures using the conventional multi-planar read were 77.5%, 99.2%, 89.9%, and 98.0% for radiologists; 46.3%, 99.7%, 92.5%, and 95.3% for residents; and 29.4%, 99.4%, 82.5%, and 93.9% for interns, respectively. Sensitivity, PPV, and NPV increased across all three groups of experience, using the reformatted single-in-plane image of the rib cage (radiologists: 85.0%, 98.6%, and 98.7%; residents: 80.0%, 92.8%, and 98.2%; interns: 66.9%, 89.9%, and 97.1%), whereas specificity did not change significantly (99.9%, 99.4%, and 99.3%). The diagnostic performance of the interns and residents was significantly better when

Improved scatter correction with factor analysis for planar and SPECT imaging

Science.gov (United States)

Knoll, Peter; Rahmim, Arman; Gültekin, Selma; Šámal, Martin; Ljungberg, Michael; Mirzaei, Siroos; Segars, Paul; Szczupak, Boguslaw

2017-09-01

Quantitative nuclear medicine imaging is an increasingly important frontier. In order to achieve quantitative imaging, various interactions of photons with matter have to be modeled and compensated. Although correction for photon attenuation has been addressed by including x-ray CT scans (accurate), correction for Compton scatter remains an open issue. The inclusion of scattered photons within the energy window used for planar or SPECT data acquisition decreases the contrast of the image. While a number of methods for scatter correction have been proposed in the past, in this work, we propose and assess a novel, user-independent framework applying factor analysis (FA). Extensive Monte Carlo simulations for planar and tomographic imaging were performed using the SIMIND software. Furthermore, planar acquisition of two Petri dishes filled with 99mTc solutions and a Jaszczak phantom study (Data Spectrum Corporation, Durham, NC, USA) using a dual head gamma camera were performed. In order to use FA for scatter correction, we subdivided the applied energy window into a number of sub-windows, serving as input data. FA results in two factor images (photo-peak, scatter) and two corresponding factor curves (energy spectra). Planar and tomographic Jaszczak phantom gamma camera measurements were recorded. The tomographic data (simulations and measurements) were processed for each angular position resulting in a photo-peak and a scatter data set. The reconstructed transaxial slices of the Jaszczak phantom were quantified using an ImageJ plugin. The data obtained by FA showed good agreement with the energy spectra, photo-peak, and scatter images obtained in all Monte Carlo simulated data sets. For comparison, the standard dual-energy window (DEW) approach was additionally applied for scatter correction. FA in comparison with the DEW method results in significant improvements in image accuracy for both planar and tomographic data sets. FA can be used as a user

Imaging skeletal anatomy of injured cervical spine specimens: comparison of single-slice vs multi-slice helical CT

Energy Technology Data Exchange (ETDEWEB)

Obenauer, S.; Alamo, L.; Herold, T.; Funke, M.; Kopka, L.; Grabbe, E. [Department of Radiology, Georg August-University Goettingen, Robert-Koch-Strasse 40, 37075 Goettingen (Germany)

2002-08-01

Our objective was to compare a single-slice CT (SS-CT) scanner with a multi-slice CT (MS-CT) scanner in the depiction of osseous anatomic structures and fractures of the upper cervical spine. Two cervical spine specimens with artificial trauma were scanned with a SS-CT scanner (HighSpeed, CT/i, GE, Milwaukee, Wis.) by using various collimations (1, 3, 5 mm) and pitch factors (1, 1.5, 2, 3) and a four-slice helical CT scanner (LightSpeed, QX/i, GE, Milwaukee, Wis.) by using various table speeds ranging from 3.75 to 15 mm/rotation for a pitch of 0.75 and from 7.5 to 30 mm/rotation for a pitch of 1.5. Images were reconstructed with an interval of 1 mm. Sagittal and coronal multiplanar reconstructions of the primary and reconstructed data set were performed. For MS-CT a tube current resulting in equivalent image noise as with SS-CT was used. All images were judged by two observers using a 4-point scale. The best image quality for SS-CT was achieved with the smallest slice thickness (1 mm) and a pitch smaller than 2 resulting in a table speed of up to 2 mm per gantry rotation (4 points). A reduction of the slice thickness rather than of the table speed proved to be beneficial at MS-CT. Therefore, the optimal scan protocol in MS-CT included a slice thickness of 1.25 mm with a table speed of 7.5 mm/360 using a pitch of 1.5 (4 points), resulting in a faster scan time than when a pitch of 0.75 (4 points) was used. This study indicates that MS-CT could provide equivalent image quality at approximately four times the volume coverage speed of SS-CT. (orig.)

The effects of slice thickness and reconstructive parameters on VR image quality in multi-slice CT

International Nuclear Information System (INIS)

Gao Zhenlong; Wang Qiang; Liu Caixia

2005-01-01

Objective: To explore the effects of slice thickness, reconstructive thickness and reconstructive interval on VR image quality in multi-slice CT, in order to select the best slice thickness and reconstructive parameters for the imaging. Methods: Multi-slice CT scan was applied on a rubber dinosaur model with different slice thickness. VR images were reconstructed with different reconstructive thickness and reconstructive interval. Five radiologists were invited to evaluate the quality of the images without knowing anything about the parameters. Results: The slice thickness, reconstructive thickness and reconstructive interval did have effects on VR image quality and the effective degree was different. The effective coefficients were V 1 =1413.033, V 2 =563.733, V 3 =390.533, respectively. The parameters interacted with the others (P<0.05). The smaller of those parameters, the better of the image quality. With a small slice thickness and a reconstructive slice equal to slice thickness, the image quality had no obvious difference when the reconstructive interval was 1/2, 1/3, 1/4 of the slice thickness. Conclusion: A relative small scan slice thickness, a reconstructive slice equal to slice thickness and a reconstructive interval 1/2 of the slice thickness should be selected for the best VR image quality. The image quality depends mostly on the slice thickness. (authors)

Diagnostic Accuracy of the Volume Rendering Images of Multi-Detector CT for the Detection of Lumbar Transverse Process Fractures

Energy Technology Data Exchange (ETDEWEB)

Lee, Yun Hak; Chun, Tong Jin [Dept. of Radiology, Eulji University Hospital, Daejeon (Korea, Republic of)

2012-01-15

To compare the accuracy of three-dimensional computed tomographic (3D CT) volume rendering techniques with axial images of multi-detector row computed tomography to identify lumbar transverse process (LTP) fractures in trauma patients. We retrospectively evaluated 42 patients with back pain as a result of blunt trauma between January and June of 2010. Two radiologists examined the 3D CT volume rendering images independently. The confirmation of a LTP fracture was based on the consensus of the axial images by the two radiologists. The results of 3D CT volume rendering images were compared with the axial images and the diagnostic powers (sensitivity, specificity, and accuracy) were calculated. Seven of the 42 patients had twenty five lumbar transverse process fractures. The diagnostic power of the 3D CT volume rendering technique is as accurate as axial images. Reader 1, sensitivity 96%, specificity 100%, accuracy 99.9%; and Reader 2 sensitivity 100%, specificity 99.8%, accuracy 99.8%. The accordance of the two radiologists was 99.8%. 3D CT volume rendering images can alternate axial images to detect lumbar transverse process fractures with good image quality.

Multi-slice spiral CT perfusion imaging of chronic obstructive pulmonary disease

International Nuclear Information System (INIS)

Shao Yanhui; Qian Nong; Xue Yuejun; Dao Yinhong

2008-01-01

Objective: To evaluate the diagnostic value of multi-slice spiral CT (MSCT) perfusion imaging in chronic obstructive pulmonary disease (COPD). Methods: Twenty COPD patients and 20 volunteers underwent 8-row detector spiral CT (MSCT) perfusion imaging using cine scan mode with 5 mm slice thickness, 0.5 s rotation time and a total scan time of 45 s with 5 s intervals. 60 ml contrast agent (300 nag I/ml) were administered at a rate of 4 ml/s from the forearm superficial vein. The imaging data were transferred to a workstation. A time-density curve and pseudo-color map were generated automatically with GE CT perfusion 3 software, the blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) were measured. Results: Time-density curve was flatter and the peak of the curve was obviously lower in COPD patients than the volunteers. The BF, BV, PS in COPD patients was (24.77±11.49) ml·min -1 ·100 g -1 , (2.48±1.02) ml/100 g and (2.75±1.13) ml· min -1 ·100 g -1 respectively. In volunteers was (290.14±107.59) ml·min -1 ·100 g -1 , (16.51 ± 5.98) ml/100 g, (8.80±3.03) ml·min -1 ·100 g -1 respectively. The MTT in COPD patients and volunteers was (10.58±4.85) s and (4.50±1.71)s respectively. The BF, BV and PS in COPD patients was lower than the volunteers, the MTY was higher (P<0.01). Conclusion: MSCT perfusion imaging is helpful for the diagnosis of COPD. (authors)

Clinical applications of SPECT/CT in imaging the extremities

International Nuclear Information System (INIS)

Huellner, Martin W.; Strobel, Klaus

2014-01-01

Today, SPECT/CT is increasingly used and available in the majority of larger nuclear medicine departments. Several applications of SPECT/CT as a supplement to or replacement for traditional conventional bone scintigraphy have been established in recent years. SPECT/CT of the upper and lower extremities is valuable in many conditions with abnormal bone turnover due to trauma, inflammation, infection, degeneration or tumour. SPECT/CT is often used in patients if conventional radiographs are insufficient, if MR image quality is impaired due to metal implants or in patients with contraindications to MR. In complex joints such as those in the foot and wrist, SPECT/CT provides exact anatomical correlation of pathological uptake. In many cases SPECT increases the sensitivity and CT the specificity of the study, increasing confidence in the final diagnosis compared to planar images alone. The CT protocol should be adapted to the clinical question and may vary from very low-dose (e.g. attenuation correction only), to low-dose for anatomical correlation, to normal-dose protocols enabling precise anatomical resolution. The aim of this review is to give an overview of SPECT/CT imaging of the extremities with a focus on the hand and wrist, knee and foot, and for evaluation of patients after joint arthroplasty. (orig.)

Clinical applications of SPECT/CT in imaging the extremities

Energy Technology Data Exchange (ETDEWEB)

Huellner, Martin W. [University Hospital Zurich, Department of Medical Radiology, Division of Nuclear Medicine, Zurich (Switzerland); Strobel, Klaus [Lucerne Cantonal Hospital, Department of Nuclear Medicine and Radiology, Lucerne (Switzerland)

2014-05-15

Today, SPECT/CT is increasingly used and available in the majority of larger nuclear medicine departments. Several applications of SPECT/CT as a supplement to or replacement for traditional conventional bone scintigraphy have been established in recent years. SPECT/CT of the upper and lower extremities is valuable in many conditions with abnormal bone turnover due to trauma, inflammation, infection, degeneration or tumour. SPECT/CT is often used in patients if conventional radiographs are insufficient, if MR image quality is impaired due to metal implants or in patients with contraindications to MR. In complex joints such as those in the foot and wrist, SPECT/CT provides exact anatomical correlation of pathological uptake. In many cases SPECT increases the sensitivity and CT the specificity of the study, increasing confidence in the final diagnosis compared to planar images alone. The CT protocol should be adapted to the clinical question and may vary from very low-dose (e.g. attenuation correction only), to low-dose for anatomical correlation, to normal-dose protocols enabling precise anatomical resolution. The aim of this review is to give an overview of SPECT/CT imaging of the extremities with a focus on the hand and wrist, knee and foot, and for evaluation of patients after joint arthroplasty. (orig.)

Diagnostic test accuracy study of 18F-sodium fluoride PET/CT, 99mTc-labelled diphosphonate SPECT/CT, and planar bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer

DEFF Research Database (Denmark)

Fonager, Randi F; Zacho, Helle D; Langkilde, Niels C

2017-01-01

The aim of this study was to prospectively compare planar, bone scan (BS) versus SPECT/CT and NaF PET/CT in detecting bone metastases in prostate cancer. Thirty-seven consecutive, newly diagnosed, prostate cancer patients with prostate specific antigen (PSA) levels ≥ 50 ng/mL and who were...... considered eligible for androgen-deprivation therapy (ADT) were included in this study. BS, SPECT/CT, and NaF PET/CT, were performed prior to treatment and were repeated after six months of ADT. Baseline images from each index test were independently read by two experienced readers. The reference standard......%, and 96%, respectively, and the negative predictive values were 60%, 77% and 75%, respectively. No statistically significant difference among the three imaging modalities was observed. All three imaging modalities showed high sensitivity and specificity. NaF PET/CT and SPECT/CT showed numerically improved...

SPECT/CT imaging in children with papillary thyroid carcinoma

International Nuclear Information System (INIS)

Kim, Hwa-Young; Gelfand, Michael J.; Sharp, Susan E.

2011-01-01

SPECT/CT improves localization of single photon-emitting radiopharmaceuticals. To determine the utility of SPECT/CT in children with papillary thyroid carcinoma. 20 SPECT/CT and planar studies were reviewed in 13 children with papillary thyroid carcinoma after total thyroidectomy. Seven studies used I-123 and 13 used I-131, after elevating TSH by T4 deprivation or intramuscular thyrotropin alfa. Eight children had one study and five children had two to four studies. Studies were performed at initial post-total thyroidectomy evaluation, follow-up and after I-131 treatment doses. SPECT/CT was performed with a diagnostic-quality CT unit in 13 studies and a localization-only CT unit in 7. Stimulated thyroglobulin was measured (except in 2 cases with anti-thyroglobulin antibodies). In 13 studies, neck activity was present but poorly localized on planar imaging; all foci of uptake were precisely localized by SPECT/CT. Two additional foci of neck uptake were found on SPECT/CT. SPECT/CT differentiated high neck uptake from facial activity. In six studies (four children), neck uptake was identified as benign by SPECT/CT (three thyroglossal duct remnants, one skin contamination, two by precise anatomical CT localization). In two children, SPECT/CT supported a decision not to treat with I-131. When SPECT/CT was unable to identify focal uptake as benign, stimulated thyroglobulin measurements were valuable. In three of 13 studies with neck uptake, SPECT/CT provided no useful additional information. SPECT/CT precisely localizes neck iodine uptake. In small numbers of patients, treatment is affected. SPECT/CT should be used when available in thyroid carcinoma patients. (orig.)

Clinical Utility of SPECT/CT Imaging Post-Radioiodine Therapy: Does It Enhance Patient Management in Thyroid Cancer?

Science.gov (United States)

Hassan, Fahim U; Mohan, Hosahalli K

2015-12-01

The aim of this study was to evaluate post-therapy iodine-131 single-photon emission computed tomography/computed tomography ((131)I-SPECT/CT) imaging in comparison to conventional planar (131)I whole-body imaging, and to assess its clinical impact on the management of patients. We retrospectively reviewed planar (131)I whole-body and (131)I-SPECT/CT imaging findings in 67 patients who underwent (131)I therapy for thyroid cancer. Two nuclear medicine physicians reviewed the scans independently. The foci of increased tracer uptake were identified in the neck, thorax and elsewhere. Within the neck, the foci of (131)I-increased uptake were graded qualitatively as probable or definite uptake in thyroid remnants and probable or definite uptake in the lymph nodes. Serum thyroglobulin level, histopathology and other imaging findings served as the reference standard. Of the 67 patients, 57 (85%) had radioiodine avid disease and 10 (15%) demonstrated non-radioiodine avid disease. Overall, post-therapy (131)I-SPECT/CT downstaged lymph node staging in 10 patients and upstaged it in 4 patients. This translated into a change of management for 9/57 (16%) patients with radioiodine avid disease. A change of management was observed in 5/10 patients with non-radioiodine avid disease confirmed in the post-(131)I-SPECT/CT study. Additionally, clinically significant findings such as incidental lung cancer, symptomatic pleural effusion and consolidation were also diagnosed in both groups of patients. In patients with thyroid cancer, (131)I-SPECT/CT is a valuable addition to standard post-therapy planar imaging. SPECT/CT also improved diagnostic confidence and provided crucial clinical information leading to change of management for a significant number of these patients.

Investigating the role of SPECT/CT in dynamic sentinel lymph node biopsy for penile cancers

Energy Technology Data Exchange (ETDEWEB)

Saad, Ziauddin Zia; Bomanji, Jamshed [University College Hospitals London, Department of Nuclear Medicine, London (United Kingdom); UCLH NHS Foundation Trust, Institute of Nuclear Medicine, 5th Floor, London (United Kingdom); Omorphos, Savvas; Malone, Peter; Nigam, Raj; Muneer, Asif [University College Hospitals London, Department of Urology, London (United Kingdom); Michopoulou, Sofia; Gacinovic, Svetislav [University College Hospitals London, Department of Nuclear Medicine, London (United Kingdom)

2017-07-15

Currently, most centres use 2-D planar lymphoscintigraphy when performing dynamic sentinel lymph node biopsy in penile cancer patients with clinically impalpable inguinal nodes. This study aimed to investigate the role of SPECT/CT following 2-D planar lymphoscintigraphy (dynamic and static) in the detection and localization of sentinel lymph nodes in the groin. A qualitative (visual) review was performed on planar followed by SPECT/CT lymphoscintigraphy in 115 consecutive patients (age 28-86 years) who underwent injection of {sup 99m}Tc-nanocolloid followed by immediate acquisition of dynamic (20 min) and early static scans (5 min) initially and further delayed static (5 min) images at 120 min followed by SPECT/CT imaging. The lymph nodes detected in each groin on planar lymphoscintigraphy and SPECT/CT were compared. A total of 440 and 467 nodes were identified on planar scintigraphy and SPECT/CT, respectively. Overall, SPECT/CT confirmed the findings of planar imaging in 28/115 cases (24%). In the remaining 87 cases (76%), gross discrepancies were observed between planar and SPECT/CT images. SPECT/CT identified 17 instances of skin contamination (16 patients, 13%) and 36 instances of in-transit lymphatic tract activity (24 patients, 20%) that had been interpreted as tracer-avid lymph nodes on planar imaging. In addition, SPECT/CT identified 53 tracer-avid nodes in 48 patients (42%) that were not visualized on planar imaging and led to reclassification of the drainage basins (pelvic/inguinal) of 27 tracer-avid nodes. The addition of SPECT/CT improved the rate of detection of true tracer-avid lymph nodes and delineated their precise (3-D) anatomic localization in drainage basins. (orig.)

Comparison of effective dose for imaging of mandible between multi-detector CT and cone-beam CT

International Nuclear Information System (INIS)

Jeong, Dae Kyo; Lee, Sang Chul; Huh, Kyung Hoe; Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul

2012-01-01

The aim of this study was to compare the effective dose for imaging of mandible between multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). An MDCT with low dose technique was also compared with them. Thermoluminescent dosimeter (TLD) chips were placed at 25 organ sites of an anthropomorphic phantom. The mandible of the phantom was exposed using 2 different types of MDCT units (Somatom Sensation 10 for standard-dose MDCT, Somatom Emotion 6 for low-dose MDCT) and 3 different CBCT units (AZ3000CT, Implagraphy, and Kavo 3D eXaM). The radiation absorbed dose was measured and the effective dose was calculated according to the ICRP 2007 report. The effective dose was the highest for Somatom Sensation 10 (425.84 μSv), followed by AZ3000CT (332.4 μSv), Somatom Emotion 6 (199.38 μSv), and 3D eXaM (111.6 μSv); it was the lowest for Implagraphy (83.09 μSv). The CBCT showed significant variation in dose level with different device. The effective doses of MDCTs were not significantly different from those of CBCTs for imaging of mandible. The effective dose of MDCT could be markedly decreased by using the low-dose technique.

Comparison of effective dose for imaging of mandible between multi-detector CT and cone-beam CT

Energy Technology Data Exchange (ETDEWEB)

Jeong, Dae Kyo; Lee, Sang Chul; Huh, Kyung Hoe; Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul [School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

2012-06-15

The aim of this study was to compare the effective dose for imaging of mandible between multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). An MDCT with low dose technique was also compared with them. Thermoluminescent dosimeter (TLD) chips were placed at 25 organ sites of an anthropomorphic phantom. The mandible of the phantom was exposed using 2 different types of MDCT units (Somatom Sensation 10 for standard-dose MDCT, Somatom Emotion 6 for low-dose MDCT) and 3 different CBCT units (AZ3000CT, Implagraphy, and Kavo 3D eXaM). The radiation absorbed dose was measured and the effective dose was calculated according to the ICRP 2007 report. The effective dose was the highest for Somatom Sensation 10 (425.84 {mu}Sv), followed by AZ3000CT (332.4 {mu}Sv), Somatom Emotion 6 (199.38 {mu}Sv), and 3D eXaM (111.6 {mu}Sv); it was the lowest for Implagraphy (83.09 {mu}Sv). The CBCT showed significant variation in dose level with different device. The effective doses of MDCTs were not significantly different from those of CBCTs for imaging of mandible. The effective dose of MDCT could be markedly decreased by using the low-dose technique.

SPECT/CT in the Diagnosis of Skull Base Osteomyelitis

International Nuclear Information System (INIS)

Damle, Nishikant Avinash; Kumar, Rakesh; Kumar, Praveen; Jaganthan, Sriram; Patnecha, Manish; Bal, Chandrasekhar; Bandopadhyaya, Gurupad; Malhotra, Arun

2011-01-01

Skull base osteomyelitis is a potentially fatal disease. We demonstrate here the utility of SPECT/CT in diagnosing this entity, which was not obvious on a planar bone scan. A 99mT c MDP bone scan with SPECT/CT was carried out on a patient with clinically suspected skull base osteomyelitis. Findings were correlated with contrast enhanced CT (CECT) and MRI. Planar images were equivocal, but SPECT/CT showed intense uptake in the body of sphenoid and petrous temporal bone as well as the atlas corresponding to irregular bone destruction on CT and MRI. These findings indicate that SPECT/CT may have an additional role beyond planar imaging in the detection of skull base osteomyelitis.

Automatic labeling and segmentation of vertebrae in CT images

Science.gov (United States)

Rasoulian, Abtin; Rohling, Robert N.; Abolmaesumi, Purang

2014-03-01

Labeling and segmentation of the spinal column from CT images is a pre-processing step for a range of image- guided interventions. State-of-the art techniques have focused either on image feature extraction or template matching for labeling of the vertebrae followed by segmentation of each vertebra. Recently, statistical multi- object models have been introduced to extract common statistical characteristics among several anatomies. In particular, we have created models for segmentation of the lumbar spine which are robust, accurate, and computationally tractable. In this paper, we reconstruct a statistical multi-vertebrae pose+shape model and utilize it in a novel framework for labeling and segmentation of the vertebra in a CT image. We validate our technique in terms of accuracy of the labeling and segmentation of CT images acquired from 56 subjects. The method correctly labels all vertebrae in 70% of patients and is only one level off for the remaining 30%. The mean distance error achieved for the segmentation is 2.1 +/- 0.7 mm.

Synchrotron-based DEI for bio-imaging and DEI-CT to image phantoms with contrast agents

International Nuclear Information System (INIS)

Rao, Donepudi V.; Swapna, Medasani; Cesareo, Roberto; Brunetti, Antonio; Akatsuka, Tako; Yuasa, Tetsuya; Zhong, Zhong; Takeda, Tohoru; Gigante, Giovanni E.

2012-01-01

The introduction of water, physiological, or iodine as contrast agents is shown to enhance minute image features in synchrotron-based X-ray diffraction radiographic and tomographic imaging. Anatomical features of rat kidney, such as papillary ducts, ureter, renal artery and renal vein are clearly distinguishable. Olfactory bulb, olfactory tact, and descending bundles of the rat brain are visible with improved contrast. - Highlights: ► Distinguishable anatomical structures features of rat kidney and rat brain are acquired with Sy-DEI in planar mode. ► Images of a small brain phantom and cylindrical phantom are acquired in tomography mode (Sy-DEI-CT) with contrast agents. ► Sy-DEI and Sy-DEI-CT techniques provide new source of information related to biological microanatomy.

Combined multi-kernel head computed tomography images optimized for depicting both brain parenchyma and bone.

Science.gov (United States)

Takagi, Satoshi; Nagase, Hiroyuki; Hayashi, Tatsuya; Kita, Tamotsu; Hayashi, Katsumi; Sanada, Shigeru; Koike, Masayuki

2014-01-01

The hybrid convolution kernel technique for computed tomography (CT) is known to enable the depiction of an image set using different window settings. Our purpose was to decrease the number of artifacts in the hybrid convolution kernel technique for head CT and to determine whether our improved combined multi-kernel head CT images enabled diagnosis as a substitute for both brain (low-pass kernel-reconstructed) and bone (high-pass kernel-reconstructed) images. Forty-four patients with nondisplaced skull fractures were included. Our improved multi-kernel images were generated so that pixels of >100 Hounsfield unit in both brain and bone images were composed of CT values of bone images and other pixels were composed of CT values of brain images. Three radiologists compared the improved multi-kernel images with bone images. The improved multi-kernel images and brain images were identically displayed on the brain window settings. All three radiologists agreed that the improved multi-kernel images on the bone window settings were sufficient for diagnosing skull fractures in all patients. This improved multi-kernel technique has a simple algorithm and is practical for clinical use. Thus, simplified head CT examinations and fewer images that need to be stored can be expected.

Lymphoscintigraphic sentinel node identification in patients with breast cancer: the role of SPECT-CT

International Nuclear Information System (INIS)

Lerman, H.; Metser, U.; Lievshitz, G.; Sperber, F.; Shneebaum, S.; Even-Sapir, E.

2006-01-01

Lymph node status is a major factor in determining the stage, appropriate therapy and outcome in patients with breast cancer. It is therefore of clinical importance to accurately identify all sentinel nodes (SNs) for each individual tumour before surgery. The purpose of this study was to assess the role of SPECT-CT lymphoscintigraphy in SN identification in patients with breast cancer. Lymphoscintigraphy comprising planar and SPECT-CT acquisition was performed in 157 consecutive patients with breast cancer (mean age 54.7±10.6, range 27-81 years) with a palpable mass (n=100), with a non-palpable mass (n=52) or post lumpectomy (n=5). Planar and SPECT-CT images were interpreted separately and the two imaging techniques were compared with respect to their ability to identify hot nodes. Planar imaging alone was negative for identification of hot nodes in 15% of the patients. SPECT-CT alone was negative in 10% and both techniques were negative in 9% of the patients. Forty-six of the total of 361 (13%) hot nodes identified by lymphoscintigraphy were detected only on SPECT-CT, including 21 nodes obscured by the scattered radiation from the injection site, nine adjacent nodes misinterpreted on planar images as a single node and 16 nodes which were missed on planar images and detected on SPECT data. SPECT-CT detected additional sites of drainage unexpected on planar images, including axillary (n=23 patients), internal mammary (n=5 patients), interpectoral (n=3 patients) and intramammary (n=2 patients) lymph node sites. Fourteen of the 329 (4%) hot lesions seen on planar images were false positive non-nodal sites of uptake that were accurately assessed by SPECT-CT and further validated by surgery. In a single patient, SPECT-CT was negative while planar images identified the SN. (orig.)

Computed tomography imaging for superior semicircular canal dehiscence syndrome

International Nuclear Information System (INIS)

Dobeli, Karen

2006-01-01

Superior semicircular canal dehiscence is a newly described syndrome of sound and/or pressure induced vertigo. Computed tomography (CT) imaging plays an important role in confirmation of a defect in the bone overlying the canal. A high resolution CT technique utilising 0.5 mm or thinner slices and multi-planar reconstructions parallel to the superior semicircular canal is required. Placement of a histogram over a suspected defect can assist CT diagnosis

Skeletal scintigraphy and SPECT/CT in orthopedic imaging

International Nuclear Information System (INIS)

Klaeser, B.; Walter, M.; Krause, T.

2011-01-01

Multi-modality imaging with SPECT-CT in orthopaedics combines the excellent sensitivity of scintigraphy with the morphological information of CT as a key for specific interpretation of findings in bone scans. The result is an imaging modality with the clear potential to prove of value even in a competitive setting dominated by MRI, and to significantly add to diagnostic imaging in orthopaedics. SPECT-CT is of great value in the diagnostic evaluation after fractures, and - in contrast to MRI - it is well suited for imaging in patients with osteosyntheses and metallic implants. In sports medicine, SPECT-CT allows for a sensitive and specific detection of osseous stress reactions before morphological changes become detectable by CT or MRI. In patients with osseous pain syndromes, actively evolving degenerative changes as a cause of pain can be identified and accurately localized. Further, particularly prospective diagnostic studies providing comparative data are needed to strengthen the position of nuclear imaging in orthopaedics and sports medicine and to help implementing SPECT/CT in diagnostic algorithms. (orig.)

Planar strain analysis of liver undergoing microwave thermal ablation using x-ray CT.

Science.gov (United States)

Weiss, Noam; Goldberg, S Nahum; Nissenbaum, Yitzhak; Sosna, Jacob; Azhari, Haim

2015-01-01

To study the planar strain effects in liver during microwave (MW) thermal ablation as a means for tracking tissue expansion and contraction as a method for improving ablation monitoring. 1.4 mm circular metallic markers were inserted into 16 ex-vivo bovine fresh liver specimens, that were subsequently ablated (with the markers inside the specimen) by 40 W of microwave energy, for 1, 2, 3, 6, and 10 min. The markers were tracked during the ablation using an x-ray CT scanner. Images were acquired every 5-10 s enabling determination of the markers' coordinates over time. The 2D principal strains were calculated for triangles formed by subgroups of three markers, and their planar strain index, Ω, was plotted vs time. In addition, the radial distance of the markers from the antenna was measured at the end of each ablation. Subsequently, the tissue was sliced parallel to the imaged planes and the ablation zone was traced and digitized. The average ablation radius was then computed and compared to the radial distance. The planar strain, Ω(t), profile demonstrated an ascending pattern until reaching a maximum at about 180 s, with a mean peak value (Ω = 1.31 ± 0.04) indicating tissue expansion. Thereafter, Ω progressively declined over the remaining duration of the ablation treatment, indicating tissue contraction. Furthermore, when plotting the ablation size vs time and the markers' mean radial distance vs time, it was found that the two curves intercepted at a time corresponding to the time of peak planar strain. By detecting the point of maximal planar strain in tissues during MW application, it is possible to noninvasively identify the location of the ablation zone front. The fact that the liver tissue proximal to the ablated zone expands during the first part of the treatment and then contracts when the ablation front reaches it, may serve as an index for monitoring the thermal treatment.

SPECT/CT imaging in bone scintigraphy of a case of clavicular osteoma

International Nuclear Information System (INIS)

Yamamoto, Yuka; Nishiyama, Yoshihiro

2014-01-01

Osteoma is a benign bone-forming tumor that usually arises in the craniofacial bones and rarely in the long bones. Clavicular involvement is extremely rare. We report a 51-year-old woman with osteoma of the left clavicle. Radiograph of the left shoulder showed a well-defined lobulated blastic mass in the proximal and mid-portion of the left clavicle. Bone scintigraphy was performed 4 hours after an intravenous injection of Tc-99m hydroxymethylene diphosphonate (HMDP). Whole-body image showed a focus of intensely increased uptake in the clavicle. Single photon emission computed tomography / computed tomography (SPECT/CT) images were also acquired and clearly showed intense uptake at the tumor site. Integrated SPECT/CT imaging supplies both functional and anatomic information about bone the SPECT imaging improves sensitivity compared with planar imaging, the CT imaging provides precise localization of the abnormal uptake, and information on the shape and structure of the abnormalities improves the specificity of the diagnosis

Multi-modality PET-CT imaging of breast cancer in an animal model using nanoparticle x-ray contrast agent and 18F-FDG

Science.gov (United States)

Badea, C. T.; Ghaghada, K.; Espinosa, G.; Strong, L.; Annapragada, A.

2011-03-01

Multi-modality PET-CT imaging is playing an important role in the field of oncology. While PET imaging facilitates functional interrogation of tumor status, the use of CT imaging is primarily limited to anatomical reference. In an attempt to extract comprehensive information about tumor cells and its microenvironment, we used a nanoparticle xray contrast agent to image tumor vasculature and vessel 'leakiness' and 18F-FDG to investigate the metabolic status of tumor cells. In vivo PET/CT studies were performed in mice implanted with 4T1 mammary breast cancer cells.Early-phase micro-CT imaging enabled visualization 3D vascular architecture of the tumors whereas delayedphase micro-CT demonstrated highly permeable vessels as evident by nanoparticle accumulation within the tumor. Both imaging modalities demonstrated the presence of a necrotic core as indicated by a hypo-enhanced region in the center of the tumor. At early time-points, the CT-derived fractional blood volume did not correlate with 18F-FDG uptake. At delayed time-points, the tumor enhancement in 18F-FDG micro-PET images correlated with the delayed signal enhanced due to nanoparticle extravasation seen in CT images. The proposed hybrid imaging approach could be used to better understand tumor angiogenesis and to be the basis for monitoring and evaluating anti-angiogenic and nano-chemotherapies.

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

International Nuclear Information System (INIS)

Chung, Gi Chung; Han, Won Jeong; Kim, Eun Kyung

2010-01-01

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 μSv (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.

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

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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.

Variation in the quality of CT images of the upper abdomen when CT automatic exposure control is employed

International Nuclear Information System (INIS)

Aizawa, Isao; Muramatsu, Yoshihisa; Nomura, Keiichi; Shimizu, Fuminori

2010-01-01

The aim of this study was to analyze the reason for variation of image quality in the upper abdomen CT with the use of CT-automatic exposure control (AEC). The CT investigated was 3D modulation in the 16 multi detector row CT (MDCT) and lung cancer screening CT (LSCT) phantom was used to simulate the patient. When there was a phase difference, an image noise increase of around 15% at the maximum was accepted. It is concluded that the major reason for variation in image quality is respiratory motion and the importance of respiration control must be recognized. (author)

Three-dimensional multislice CT imaging of otitis media

International Nuclear Information System (INIS)

Suzuki, Miyako; Yoshikawa, Hiroshi; Hosokawa, Akira; Furukawa, Tomoyasu; Ichikawa, Ginichiro; Wada, Akihiro; Ando, Ichiro

2002-01-01

In recent years, the multislice CT system has come into practical use that enables table movement of half mm, resulting in a significant improvement in resolution. The use of this CT system enables to depict the entire auditory ossicles, including the stapes. 3D reconstruction was performed using helical CT data in 5 patients with chronic otitis media and 5 patients with cholesteatoma. An Aquilion Multi (Toshiba) multislice helical CT scanner and a Xtension (Toshiba) image workstation were used in this study. We demonstrated the 3D display with axial, coronal and sagittal images. Compared with the normal ears, it was necessary to set a higher threshold for the affected ears. It is important to select suitable threshold for demonstration of 3D images optimally. Bone destruction of the stapes was confirmed at surgery in 2 ears. The stapes was observed at 3D-CT imaging in other 18 ears. It was found that the 3D images of the ossicular destruction in ears with cholesteatoma were consistent with surgical findings. It is therefore concluded that 3D imaging of the middle ear using a multislice CT scanner is clinically useful. (author)

Three-dimensional multislice CT imaging of otitis media

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Suzuki, Miyako [Yanagibasi Hospital, Tokyo (Japan); Yoshikawa, Hiroshi; Hosokawa, Akira; Furukawa, Tomoyasu; Ichikawa, Ginichiro [Juntendo Univ., Tokyo (Japan). School of Medicine; Wada, Akihiro; Ando, Ichiro [Juntendo Univ., Chiba (Japan). Urayasu Hospital

2002-07-01

In recent years, the multislice CT system has come into practical use that enables table movement of half mm, resulting in a significant improvement in resolution. The use of this CT system enables to depict the entire auditory ossicles, including the stapes. 3D reconstruction was performed using helical CT data in 5 patients with chronic otitis media and 5 patients with cholesteatoma. An Aquilion Multi (Toshiba) multislice helical CT scanner and a Xtension (Toshiba) image workstation were used in this study. We demonstrated the 3D display with axial, coronal and sagittal images. Compared with the normal ears, it was necessary to set a higher threshold for the affected ears. It is important to select suitable threshold for demonstration of 3D images optimally. Bone destruction of the stapes was confirmed at surgery in 2 ears. The stapes was observed at 3D-CT imaging in other 18 ears. It was found that the 3D images of the ossicular destruction in ears with cholesteatoma were consistent with surgical findings. It is therefore concluded that 3D imaging of the middle ear using a multislice CT scanner is clinically useful. (author)

Improved detection of sentinel lymph nodes in SPECT/CT images acquired using a low- to medium-energy general-purpose collimator.

Science.gov (United States)

Yoneyama, Hiroto; Tsushima, Hiroyuki; Kobayashi, Masato; Onoguchi, Masahisa; Nakajima, Kenichi; Kinuya, Seigo

2014-01-01

The use of the low-energy high-resolution (LEHR) collimator for lymphoscintigraphy causes the appearance of star-shaped artifacts at injection sites. The aim of this study was to confirm whether the lower resolution of the low- to medium-energy general-purpose (LMEGP) collimator is compensated by decrease in the degree of septal penetration and the reduction in star-shaped artifacts. A total of 106 female patients with breast cancer, diagnosed by biopsy, were enrolled in this study. Tc phytate (37 MBq, 1 mCi) was injected around the tumor, and planar and SPECT/CT images were obtained after 3 to 4 hours. When sentinel lymph nodes (SLNs) could not be identified from planar and SPECT/CT images by using the LEHR collimator, we repeated the study with the LMEGP collimator. Planar imaging performed using the LEHR and LEHR + LMEGP collimators positively identified SLNs in 96.2% (102/106) and 99.1% (105/106) of the patients, respectively. Using combination of planar and SPECT/CT imaging with the LEHR and LEHR + LMEGP collimators, SLNs were positively identified in 97.2% (103/106) and 100% (106/106) of the patients, respectively. The LMEGP collimator provided better results than the LEHR collimator because of the lower degree of septal penetration. The use of the LMEGP collimator improved SLN detection.

NP-59 SPECT/CT Imaging in Stage 1 Hypertensive and Atypical Primary Aldosteronism: A 5-Year Retrospective Analysis of Clinicolaboratory and Imaging Features

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Yi-Chun Chen

2013-01-01

Full Text Available Objective. We retrospectively analyzed all primary aldosteronism (PA patients undergoing NP-59 SPECT/CT imaging with regard to their clinicolaboratory and imaging features, investigation, and outcomes. Material and Methods. 11 PA patients who presented to our hospital for NP-59 SPECT/CT imaging between April 2007 and March 2012 and managed here were analyzed. Results. Among 11 PA patients, eight (73% had stage 1 hypertension, three (27% stage 2 hypertension, four (36% normal plasma aldosterone concentration, nine (82% nonsuppressed plasma renin activity (PRA, six (55% normal aldosterone-renin-ratio (ARR, eight (73% serum potassium ≧3 mEq/L, seven (64% subclinical presentation, seven (64% negative confirmatory testing, and four (36% inconclusive results on CT scan and seven (64% on planar NP-59 scan. All 11 (100% patients had positive results on NP-59 SPECT/CT scan. Two (18% met typical triad and nine (82% atypical triad. Among nine atypical PA patients, three (33% had clinical presentation, six (67% subclinical presentation, six (67% negative confirmatory testing, and four (44% inconclusive results on CT scan and six (67% on planar NP-59 scan. All patients had improved outcomes. Significant differences between typical and atypical PA existed in PRA and ARR. Conclusions. NP-59 SPECT/CT may provide diagnostic potential in stage 1 hypertensive and atypical PA.

CT and MR imaging features of mucinous tubular and spindle cell carcinoma of the kidneys. A multi-institutional review

Energy Technology Data Exchange (ETDEWEB)

Cornelis, F.; Grenier, N. [Pellegrin Hospital, Department of Radiology, Bordeaux (France); Ambrosetti, D. [Pasteur Hospital, Department of Pathology, Nice (France); Rocher, L. [Kremlin-Bicetre Hospital, Department of Radiology, Paris (France); Derchi, L.E. [University of Genoa, IRCCS AOU Ospedale, San Martino IST, Department of Health Sciences (DISSAL), Genoa (Italy); Renard, B.; Puech, P. [Claude Huriez Hospital, Department of Radiology, Lille (France); Claudon, M. [Brabois Hospital, Department of Radiology, Vandoeuvre-les-Nancy (France); Rouviere, O. [E. Herriot Hospital, Department of Radiology, Lyon (France); Ferlicot, S. [Kremlin-Bicetre Hospital, Department of Pathology, Paris (France); Roy, C. [Civil Hospital, Department of Radiology, Strasbourg (France); Yacoub, M. [Pellegrin Hospital, Department of Pathology, Bordeaux (France); Bernhard, J.C. [Pellegrin Hospital, Department of Urologic Surgery, Bordeaux (France)

2017-03-15

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a recently identified renal malignancy. Diagnosis of this rare subtype of renal tumour can be challenging for pathologists, and as such, any additional data would be helpful to improve diagnostic reliability. As imaging features of this new and rare sub-type have not yet been clearly described, the purpose of this study was to describe the main radiologic features on computed tomography (CT) and magnetic resonance imaging (MRI), based jointly on the literature and findings from a multi-institutional retrospective review of pathology and imaging databases. Using a combination of CT/MRI features, diagnosis of MTSCC could be suggested in many cases. A combination of slow enhancement with plateau on dynamic contrast-enhanced CT/MRI, intermediate to high T2 signal intensity contrasting with low apparent diffusion coefficient values on MRI appeared evocative of this diagnosis. (orig.)

Skeletal scintigraphy and SPECT/CT in orthopedic imaging; Knochenszintigrafie und SPECT/CT bei orthopaedischen Fragestellungen

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Klaeser, B.; Walter, M.; Krause, T. [Inselspital Bern (Switzerland). Universitaetsklinik fuer Nuklearmedizin

2011-03-15

Multi-modality imaging with SPECT-CT in orthopaedics combines the excellent sensitivity of scintigraphy with the morphological information of CT as a key for specific interpretation of findings in bone scans. The result is an imaging modality with the clear potential to prove of value even in a competitive setting dominated by MRI, and to significantly add to diagnostic imaging in orthopaedics. SPECT-CT is of great value in the diagnostic evaluation after fractures, and - in contrast to MRI - it is well suited for imaging in patients with osteosyntheses and metallic implants. In sports medicine, SPECT-CT allows for a sensitive and specific detection of osseous stress reactions before morphological changes become detectable by CT or MRI. In patients with osseous pain syndromes, actively evolving degenerative changes as a cause of pain can be identified and accurately localized. Further, particularly prospective diagnostic studies providing comparative data are needed to strengthen the position of nuclear imaging in orthopaedics and sports medicine and to help implementing SPECT/CT in diagnostic algorithms. (orig.)

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Low-activity 124I-PET/low-dose CT versus 99mTc-pertechnetate planar scintigraphy or 99mTc-pertechnetate single-photon emission computed tomography of the thyroid: a pilot comparison.

Science.gov (United States)

Darr, Andreas M; Opfermann, Thomas; Niksch, Tobias; Driesch, Dominik; Marlowe, Robert J; Freesmeyer, Martin

2013-10-01

The standard thyroid functional imaging method, 99mTc-pertechnetate (99mTc-PT) planar scintigraphy, has technical drawbacks decreasing its sensitivity in detecting nodules or anatomical pathology. 124I-PET, lacking these disadvantages and allowing simultaneous CT, may have greater sensitivity for these purposes. We performed a blinded pilot comparison of 124I-PET(/CT) versus 99mTc-PT planar scintigraphy or its cross-sectional enhancement, 99mTc-PT single-photon emission CT (SPECT), in characterizing the thyroid gland with benign disease. Twenty-one consecutive adults with goiter underwent low-activity (1 MBq/0.027 mCi) 124I-PET/low-dose (30 mAs) CT, 99mTc-PT planar scintigraphy, and 99mTc-PT-SPECT. Endpoints included the numbers of “hot spots” with/without central photopenia and “cold spots” detected, the proportion of these lesions with morphological correlates, the mean volume and diameter of visualized nodules, and the number of cases of lobus pyramidalis or retrosternal thyroid tissue identified. 124I-PET detected significantly more “hot spots” with/without central photopenia (P < 0.001), significantly more nodules (P < 0.001), and more “cold spots” than did 99mTc-PT planar scintigraphy or 99mTc-PT-SPECT, including all lesions seen on the 99mTc-PT modalities. Ultrasonographic correlates were found for all nodules visualized on all 3 modalities and 92.5% of nodules seen only on 124I-PET. Nodules discernible only on 124I-PET had significantly smaller mean volume or diameter (P < 0.001) than did those visualized on 99mTc-PT planar scintigraphy or 99mTc-PT-SPECT. 124I-PET(/CT) identified significantly more patients with a lobus pyramidalis (P < 0.001) or retrosternal thyroid tissue (P < 0.05). 124I-PET(/CT) may provide superior imaging of benign thyroid disease compared to planar or cross-sectional 99mTc-PT scintigraphy.

Anatomical details of the brainstem and cranial nerves visualized by high resolution readout-segmented multi-shot echo-planar diffusion-weighted images using unidirectional MPG at 3T

International Nuclear Information System (INIS)

Naganawa, Shinji; Yamazaki, Masahiro; Kawai, Hisashi; Sone, Michihiko; Nakashima, Tsutomu; Isoda, Haruo

2011-01-01

We compared diffusion-weighted imaging (DWI) with readout-segmented multi-shot echo-planar imaging (rs-EPI) and single-shot EPI, both using unidirectional motion-probing gradient, in 10 patients for visualization of the anatomical structures in the brainstem. DWI by rs-EPI was significantly better than DWI by single-shot EPI for visualizing the medial longitudinal fasciculus, lateral lemniscus, corticospinal tract, and seventh/eighth cranial nerves and offered significantly less distortion of the brainstem. (author)

Peritoneal mesothelioma: CT and MRI findings

International Nuclear Information System (INIS)

Puvaneswary, M.; Chen, S.; Proietto, T.

2002-01-01

Two patients with histologically proven diagnosis of peritoneal mesothelioma are presented. Both patients had CT scans of the abdomen. The second patient was also examined with MRI. Although imaging findings are striking, they are non-specific and diagnosing peritoneal mesothelioma in the absence of pleural calcification or pleural plaque on chest radiograph or CT is difficult. However, it is possible to suggest the correct diagnosis in a patient with the presence of non-calcified omental and peritoneal infiltration or masses without liver secondaries or lymphadenopathy. Magnetic resonance imaging with its multi-planar capabilities is a highly sensitive non-invasive modality in the evaluation of malignant peritoneal mesothelioma and can demonstrate the exact site and clarify whether the mass is arising from the peritoneal surface or within a visceral organ. Copyright (2002) Blackwell Science Pty Ltd

SPECT/CT Fusion in the Diagnosis of Hyperparathyroidism

International Nuclear Information System (INIS)

Monzen, Yoshio; Tamura, Akihisa; Okazaki, Hajime; Kurose, Taichi; Kobayashi, Masayuki; Kuraoka, Masatsugu

2015-01-01

In this study, we aimed to analyze the relationship between the diagnostic ability of fused single photon emission computed tomography/ computed tomography (SPECT/CT) images in localization of parathyroid lesions and the size of adenomas or hyperplastic glands. Five patients with primary hyperparathyroidism (PHPT) and 4 patients with secondary hyperparathyroidism (SHPT) were imaged 15 and 120 minutes after the intravenous injection of technetium99m-methoxyisobutylisonitrile ( 99m Tc-MIBI). All patients underwent surgery and 5 parathyroid adenomas and 10 hyperplastic glands were detected. Pathologic findings were correlated with imaging results. The SPECT/CT fusion images were able to detect all parathyroid adenomas even with the greatest axial diameter of 0.6 cm. Planar scintigraphy and SPECT imaging could not detect parathyroid adenomas with an axial diameter of 1.0 to 1.2 cm. Four out of 10 (40%) hyperplastic parathyroid glands were diagnosed, using planar and SPECT imaging and 5 out of 10 (50%) hyperplastic parathyroid glands were localized, using SPECT/CT fusion images. SPECT/CT fusion imaging is a more useful tool for localization of parathyroid lesions, particularly parathyroid adenomas, in comparison with planar and or SPECT imaging

Quantitative imaging of excised osteoarthritic cartilage using spectral CT

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Rajendran, Kishore; Bateman, Christopher J.; Younis, Raja Aamir; De Ruiter, Niels J.A.; Ramyar, Mohsen; Anderson, Nigel G. [University of Otago - Christchurch, Department of Radiology, Christchurch (New Zealand); Loebker, Caroline [University of Otago, Christchurch Regenerative Medicine and Tissue Engineering Group, Department of Orthopaedic Surgery and Musculoskeletal Medicine, Christchurch (New Zealand); University of Twente, Department of Developmental BioEngineering, Enschede (Netherlands); Schon, Benjamin S.; Hooper, Gary J.; Woodfield, Tim B.F. [University of Otago, Christchurch Regenerative Medicine and Tissue Engineering Group, Department of Orthopaedic Surgery and Musculoskeletal Medicine, Christchurch (New Zealand); Chernoglazov, Alex I. [University of Canterbury, Human Interface Technology Laboratory New Zealand, Christchurch (New Zealand); Butler, Anthony P.H. [University of Otago - Christchurch, Department of Radiology, Christchurch (New Zealand); European Organisation for Nuclear Research (CERN), Geneva (Switzerland); MARS Bioimaging, Christchurch (New Zealand)

2017-01-15

To quantify iodine uptake in articular cartilage as a marker of glycosaminoglycan (GAG) content using multi-energy spectral CT. We incubated a 25-mm strip of excised osteoarthritic human tibial plateau in 50 % ionic iodine contrast and imaged it using a small-animal spectral scanner with a cadmium telluride photon-processing detector to quantify the iodine through the thickness of the articular cartilage. We imaged both spectroscopic phantoms and osteoarthritic tibial plateau samples. The iodine distribution as an inverse marker of GAG content was presented in the form of 2D and 3D images after applying a basis material decomposition technique to separate iodine in cartilage from bone. We compared this result with a histological section stained for GAG. The iodine in cartilage could be distinguished from subchondral bone and quantified using multi-energy CT. The articular cartilage showed variation in iodine concentration throughout its thickness which appeared to be inversely related to GAG distribution observed in histological sections. Multi-energy CT can quantify ionic iodine contrast (as a marker of GAG content) within articular cartilage and distinguish it from bone by exploiting the energy-specific attenuation profiles of the associated materials. (orig.)

Effects of dose reduction on multi-detector computed tomographic images in evaluating the maxilla and mandible for pre-surgical implant planning: a cadaveric study.

Science.gov (United States)

Koizumi, Hiroshi; Sur, Jaideep; Seki, Kenji; Nakajima, Koh; Sano, Tsukasa; Okano, Tomohiro

2010-08-01

To assess effects of dose reduction on image quality in evaluating maxilla and mandible for pre-surgical implant planning using cadavers. Six cadavers were used for the study using multi-detector computed tomography (CT) operated at 120 kV and the variable tube current of 80, 40, 20 and 10 mA. A slice thickness of 0.625 mm and pitch 1 were used. Multi-planar images perpendicular and parallel to dentitions were created. The images were evaluated by five oral radiologists in terms of visibility of the anatomical landmarks including alveolar crest, mandibular canal, floors of the maxillary sinus and nasal cavity, contours/cortical layer of jaw bones and the details of trabecular bone. Observers were asked to determine the quality of the images in comparison with 80 mA images based on the criteria: excellent, good, fair or non-diagnostic. The average scores of all observers were calculated for each specimen in all exposure conditions. The 40 mA images could visualize such landmarks and were evaluated to be same or almost equivalent in quality to the 80 mA images. Even the 20 mA images could be accepted just for diagnostic purpose for implant with substantial deterioration of the image quality. The 10 mA images may not be accepted because of the obscured contour caused by image noise. Significant dose reduction by lowering mA can be utilized for pre-surgical implant planning in multi-detector CT.

CT imaging of bronchus related to solitary pulmonary lesion: comparison of minimum intensity projection and multi-planar reconstruction

International Nuclear Information System (INIS)

Zhou Jun; Shan Fei; Zhang Zhiyong; Yang Shan; Zhang Xingwei; Wu Dong; Zhan Songhua

2011-01-01

Objective: To investigate the clinical value of 64-slice computed tomography with MinIP and MPR for imaging the bronchus related to a solitary pulmonary lesion (SPL). Methods: Seventy-five subjects with solitary pulmonary lesions underwent chest 64-slice CT and their bronchi were analyzed retrospectively. All images of thin-section (0.625 mm) were reconstructed with MPR and MinIP into images of 1, 2, 3, and 5 mm thickness and 1 mm gap in two orthogonal planes along the long axis of bronchus related to the SPL. The image quality of four series of MinIP and MPR images was evaluated in the aspect of bronchus visibility and pulmonary vascular masking. One-way ANOVA with Bonferroni correction and interclass correlation coefficient were used in the statistical analysis. Results: (1) The mean scores of display of the bronchi on MinIP images of four series (4.85, 4.77 and 4.84, 4.63 and 4.67, 4.25 and 4.28, in 1, 2, 3, and 5 mm thickness, respectively) and on MPR images of 1 or 2 mm thickness (4.77 and 4.76, 4.04 and 4.27, in 1 and 2 mm thickness, respectively) were good or excellent. MPR images of 1 mm thickness and MinIP images of 1-3 mm thickness showed no significant differences (t=0.318, P> 0.05 for all), but they were superior to MinIP images of 5 mm thickness (t=6.318 and 6.610, P 0.05). (2) The effect of suppression of pulmonary vascular markings on MinIP images was better with the increase of slice thickness (F= 45.312 and 40.415, P<0.01). The mean scores of MinIP images of 3 mm and 5 mm thickness (4.67 and 4.64, 5.00 and 4.97, for 3 and 5 mm thickness, respectively) were good or excellent, but MinIP images of 2 mm thickness were just acceptable. Conclusion: MinIP images of 3 mm thickness may display the bronchus related to SPL more clearly. (authors)

Modelling the Siemens SOMATOM Sensation 64 Multi-Slice CT (MSCT) Scanner

International Nuclear Information System (INIS)

Amin, A T Mohd; Rahni, A A Abd

2017-01-01

Reconstructing large volumetric 3D images with minimal radiation dosage exposure with reduced scanning time has been one of the main objectives in the advancement of CT development. One of its advancement is the introduction of multi-slice arc detector geometry from a cone-beam source in third generation scanners. In solving this complex geometry, apart from the known vast computations in CT image reconstruction due to large CT images, iterative reconstruction methods are preferred compared to analytic methods due to its flexibility in image reconstruction. A scanner of interest that has this type of geometry is the Siemens SOMATOM Sensation 64 Multi-Slice CT (MSCT) Scanner , which has a total of 32 slices with 672 detector elements on each slice. In this paper, the scanner projection is modelled via the intersecting lengths between each ray (exhibited from the source to the detector elements) with the scanned image voxels, which are evaluated using the classical Siddon’s algorithm to generate the system matrix, H . This is a prerequisite to perform various iterative reconstruction methods, which involves solving the inverse problem arising from the linear equation: S = H· I; where S is the projections produced from the image, I. Due to the ‘cone-beam geometry’ along the z -axis, the effective field-of-view (FOV) with voxel dimensions (0.4×0.4×0.4) mm 3 is 512×512×32 voxels. The scanner model is demonstrated by reconstructing an image from simulated projections using the analytic Feldkamp-Davis-Kress (FDK) method against basic iterative image reconstruction methods. (paper)

The simple method to co-register planar image with photograph

International Nuclear Information System (INIS)

Jang, Sung June; Kim, Seok Ki; Kang, Keon Wook

2005-01-01

Generally scintigraphic image presents the highly specific functional information. Sometimes, there can be limited information of patients anatomical landmark required to identify the lesion in planar nuclear medicine image. In this study, we applied the simple fusion method of planar scintigraphy and plain photography and validated the techniques with our own software. We used three fiducial marks which were comprised with Tc-99m. We obtained planar image with single head gamma camera (ARGUS ADAC laboratory, USA) and photograph using a general digital camera (CANON JAPAN). The coordinates of three marks were obtained in photograph and planar scintigraphy image. Based on these points, we took affine transformation and then fused these two images. To evaluate the precision, we compared with different depth. To find out the depth of lesion, the images were acquired in different angles and we compared the real depth and the geometrically calculated depth. At the same depth with mark, the each discordance was less than 1 mm. When the photograph were taken at the distance with 1 m and 2 m, the point 30 cm off the center were discordant in 5 mm and 2 mm each. We used this method in the localization of the remnant thyroid tissue on I-131 whole body scan with photo image. The simple method to co-register planar image with photography was reliable and easy to use. By this method, we could localize the lesion on the planar scintigraphy more accurately with other planar images (i.e. photograph) and predict the depth of the lesion without tomographic image

The value of filtered planar images in pediatric DMSA scans

International Nuclear Information System (INIS)

Mohammed, A.M.; Naddaf, S.Y.; Elgazzar, A.H.; Al-Abdul Salam, A.A.; Omar, A.A.

2006-01-01

The study was designed to demonstrate the value of filtered planar images in paediatric DMSA scanning. One hundred and seventy three patients ranged in age from 15 days to 12 years (mean: 4.3 years) with urinary tract infection (UTI) and clinical and/or laboratory suspicion of acute pyelonephritis (APN) were retrospectively studied. Planar images were filtered using Butterworth filter. The scan findings were reported as positive, negative or equivocal for cortical defects. Each scan was read in a double-blind fashion by two nuclear medicine physicians to evaluate inter-observer variations. Each kidney was divided into three zones, upper, middle and lower, and each zone was graded as positive, negative or equivocal for the presence of renal defects. Renal cortical defects were found in 66 patients (91 kidneys and 186 zones) with filtered images, 58 patients (81 kidneys and 175 zones) with planar images, and 69 patients (87 kidneys and 180 zones) with SPECT images. McNemar's test revealed statistically significant difference between filtered and planar images (p=0.038 for patients, 0.021 for kidneys and 0.034 for number of zones). Inter-observer agreement was 0.877 for filtered images, 0.915 for planar images and 0.915 for SPECT images. It was concluded that filtered planar images of renal cortex are comparable to SPECT images and can be used effectively in place of SPECT, when required, to shorten imaging time and eliminate motion artifacts, especially in the paediatric population. (author)

WE-E-18C-01: Multi-Energy CT: Current Status and Recent Innovations

International Nuclear Information System (INIS)

Pelc, N; McCollough, C; Yu, L; Schmidt, T

2014-01-01

Conventional computed tomography (CT) uses a single polychromatic x-ray spectrum and energy integrating detectors, and produces images whose contrast depends on the effective attenuation coefficient of the broad spectrum beam. This can introduce errors from beam hardening and does not produce the optimal contrast-to-noise ratio. In addition, multiple materials can have the same effective attenuation coefficient, causing different materials to be indistinguishable in conventional CT images. If transmission measurements at two or more energies are obtained, even with polychromatic beams, more specific information about the object can be obtained. If the object does not contain materials with k-edges in the spectrum, the x-ray attenuation can be well-approximated by a linear combination of two processes (photoelectric absorption and Compton scattering) or, equivalently, two basis materials. For such cases, two spectral measurements suffice, although additional measurements can provide higher precision. If K-edge materials are present, additional spectral measurements can allow these materials to be isolated. Current commercial implementations use varied approaches, including two sources operating a different kVp, one source whose kVp is rapidly switched in a single scan, and a dual layer detector that can provide spectral information in every reading. Processing of the spectral information can be performed in the raw data domain or in the image domain. The process of calculating the amount of the two basis functions implicitly corrects for beam hardening and therefore can lead to improvements in quantitative accuracy. Information can be extracted to provide material specific information beyond that of conventional CT. This additional information has been shown to be important in several clinical applications, and can also lead to more efficient clinical protocols. Recent innovations in x-ray sources, detectors, and systems have made multi-energy CT much more practical

Multi-energy CT based on a prior rank, intensity and sparsity model (PRISM)

International Nuclear Information System (INIS)

Gao, Hao; Osher, Stanley; Yu, Hengyong; Wang, Ge

2011-01-01

We propose a compressive sensing approach for multi-energy computed tomography (CT), namely the prior rank, intensity and sparsity model (PRISM). To further compress the multi-energy image for allowing the reconstruction with fewer CT data and less radiation dose, the PRISM models a multi-energy image as the superposition of a low-rank matrix and a sparse matrix (with row dimension in space and column dimension in energy), where the low-rank matrix corresponds to the stationary background over energy that has a low matrix rank, and the sparse matrix represents the rest of distinct spectral features that are often sparse. Distinct from previous methods, the PRISM utilizes the generalized rank, e.g., the matrix rank of tight-frame transform of a multi-energy image, which offers a way to characterize the multi-level and multi-filtered image coherence across the energy spectrum. Besides, the energy-dependent intensity information can be incorporated into the PRISM in terms of the spectral curves for base materials, with which the restoration of the multi-energy image becomes the reconstruction of the energy-independent material composition matrix. In other words, the PRISM utilizes prior knowledge on the generalized rank and sparsity of a multi-energy image, and intensity/spectral characteristics of base materials. Furthermore, we develop an accurate and fast split Bregman method for the PRISM and demonstrate the superior performance of the PRISM relative to several competing methods in simulations. (papers)

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-12-15

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

Comparison of sequential planar 177Lu-DOTA-TATE dosimetry scans with 68Ga-DOTA-TATE PET/CT images in patients with metastasized neuroendocrine tumours undergoing peptide receptor radionuclide therapy

International Nuclear Information System (INIS)

Sainz-Esteban, Aurora; Carril, Jose Manuel; Prasad, Vikas; Schuchardt, Christiane; Zachert, Carolin; Baum, Richard P.

2012-01-01

The aim of the study was to compare sequential 177 Lu-DOTA-TATE planar scans ( 177 Lu-DOTA-TATE) in patients with metastasized neuroendocrine tumours (NET) acquired during peptide receptor radionuclide therapy (PRRT) for dosimetry purposes with the pre-therapeutic 68 Ga-DOTA-TATE positron emission tomography (PET)/CT ( 68 Ga-DOTA-TATE) maximum intensity projection (MIP) images obtained in the same patients concerning the sensitivity of the different methods. A total of 44 patients (59 ± 11 years old) with biopsy-proven NET underwent 68 Ga-DOTA-TATE and 177 Lu-DOTA-TATE imaging within 7.9 ± 7.5 days between the two examinations. 177 Lu-DOTA-TATE planar images were acquired at 0.5, 2, 24, 48 and 72 h post-injection; lesions were given a score from 0 to 4 depending on the uptake of the radiopharmaceutical (0 being lowest and 4 highest). The number of tumour lesions which were identified on 177 Lu-DOTA-TATE scans (in relation to the acquisition time after injection of the therapeutic dose as well as with regard to the body region) was compared to those detected on 68 Ga-DOTA-TATE studies obtained before PRRT. A total of 318 lesions were detected; 280 (88%) lesions were concordant. Among the discordant lesions, 29 were 68 Ga-DOTA-TATE positive and 177 Lu-DOTA-TATE negative, whereas 9 were 68 Ga-DOTA-TATE negative and 177 Lu-DOTA-TATE positive. The sensitivity, positive predictive value and accuracy for 177 Lu-DOTA-TATE as compared to 68 Ga-DOTA-TATE were 91, 97 and 88%, respectively. Significantly more lesions were seen on the delayed (72 h) 177 Lu-DOTA-TATE images (91%) as compared to the immediate (30 min) images (68%). The highest concordance was observed for bone metastases (97%) and the lowest for head/neck lesions (75%). Concordant lesions (n = 77; mean size 3.8 cm) were significantly larger than discordant lesions (n = 38; mean size 1.6 cm) (p max ). However, concordant liver lesions with a score from 1 to 3 in the 72-h 177 Lu-DOTA-TATE scan had a lower SUV max

Megavoltage planar and cone-beam imaging with low-Z targets: dependence of image quality improvement on beam energy and patient separation.

Science.gov (United States)

Robar, James L; Connell, Tanner; Huang, Weihong; Kelly, Robin G

2009-09-01

The purpose of this study is to investigate the improvement of megavoltage planar and cone-beam CT (CBCT) image quality with the use of low atomic number (Z) external targets in the linear accelerator. In this investigation, two experimental megavoltage imaging beams were generated by using either 3.5 or 7.0 MeV electrons incident on aluminum targets installed above the level of the carousel in a linear accelerator (2100EX, Varian Medical, Inc., Palo Alto, CA). Images were acquired using an amorphous silicon detector panel. Contrast-to-noise ratio (CNR) in planar and CBCT images was measured as a function of dose and a comparison was made between the imaging beams and the standard 6 MV therapy beam. Phantoms of variable diameter were used to examine the loss of contrast due to beam hardening. Porcine imaging was conducted to examine qualitatively the advantages of the low-Z target approach in CBCT. In CBCT imaging CNR increases by factors as high as 2.4 and 4.3 for the 7.0 and 3.5 MeV/Al beams, respectively, compared to images acquired with 6 MV. Similar factors of improvement are observed in planar imaging. For the imaging beams, beam hardening causes a significant loss of the contrast advantage with increasing phantom diameter; however, for the 3.5 MeV/Al beam and a phantom diameter of 25 cm, a contrast advantage remains, with increases of contrast by factors of 1.5 and 3.4 over 6 MV for bone and lung inhale regions, respectively. The spatial resolution is improved slightly in CBCT images for the imaging beams. CBCT images of a porcine cranium demonstrate qualitatively the advantages of the low-Z target approach, showing greater contrast between tissues and improved visibility of fine detail. The use of low-Z external targets in the linear accelerator improves megavoltage planar and CBCT image quality significantly. CNR may be increased by a factor of 4 or greater. Improvement of the spatial resolution is also apparent.

Advances in CT imaging for urolithiasis

Directory of Open Access Journals (Sweden)

Yasir Andrabi

2015-01-01

Full Text Available Urolithiasis is a common disease with increasing prevalence worldwide and a lifetime-estimated recurrence risk of over 50%. Imaging plays a critical role in the initial diagnosis, follow-up and urological management of urinary tract stone disease. Unenhanced helical computed tomography (CT is highly sensitive (>95% and specific (>96% in the diagnosis of urolithiasis and is the imaging investigation of choice for the initial assessment of patients with suspected urolithiasis. The emergence of multi-detector CT (MDCT and technological innovations in CT such as dual-energy CT (DECT has widened the scope of MDCT in the stone disease management from initial diagnosis to encompass treatment planning and monitoring of treatment success. DECT has been shown to enhance pre-treatment characterization of stone composition in comparison with conventional MDCT and is being increasingly used. Although CT-related radiation dose exposure remains a valid concern, the use of low-dose MDCT protocols and integration of newer iterative reconstruction algorithms into routine CT practice has resulted in a substantial decrease in ionizing radiation exposure. In this review article, our intent is to discuss the role of MDCT in the diagnosis and post-treatment evaluation of urolithiasis and review the impact of emerging CT technologies such as dual energy in clinical practice.

Synthetic display of three-dimensional CT and MPR for gastric neoplasm

International Nuclear Information System (INIS)

Ogura, Toshihiro; Maruyama, Masakazu

1998-01-01

We attempted to obtain synthesized three dimensional (3D) and MPR (Multi Planar Reconstruction) helical CT scans (3D-MPR-CT) of gastric neoplasm by using the air as a contrast medium, and we assessed the usefulness of 3D-MPR-CT gastroendoscopy in the diagnosis of gastric neoplasm. Five minutes before the scan, 20 mg Scopolamine Butylbromide (Buscopan) was injected intramuscularly to minimize gastric peristalsis. An effervescent agent (bubble-make granules) was fed to extend the stomach wall. Non-ionic contrast material (100 mL) was power injected immediately before the scan start. Axial images were obtained with an intersection gap of 5-mm, a 5-mm/sec table speed, and 1-mm reconstruction intervals. 3D-MPR-CT images were reconstructed from these images. In abdominal study, 3D-MPR-CT images enabled the visualization of neoplasm and its adjacent structures in versatile directions, including a view similar to endoscopic observation, proximal aspect of narrowing by tumor and also could get the information about invasive depth of gastric neoplasm. Reports on some clinical cases and the advantages and disadvantages of 3D-MPR-CT gastroendoscopy were discussed. (author)

Budd-Chiari syndrome: dynamic enhancement findings with multi-slice helical CT and CT angiography analysis

International Nuclear Information System (INIS)

Meng Xiaochun; Shan Hong; Zhu Kangshun; Xu Chuan; Zhang Jiansheng; Liu Lingyun; Ye Binbin

2005-01-01

Objective: To investigate the dynamic enhancement regulations of liver and their mechanism in Budd-Chiari syndrome (BCS) by using multi-slice CT and evaluate the value of CT angiography in the diagnosis of BCS. Methods: 28 cases with BCS confirmed by digital subtraction angiography (DSA) were retrospectively analyzed. All patients underwent dynamic enhancement examinations with multi-slice CT within 1 week before DSA. The relevant vessels were reconstructed respectively with MIP, VR and MPR. Compared with the results of DSA, we analyzed the dynamic enhancement regulations of liver in BCS, estimated the value of dynamic enhancement CT exams and CTA techniques in judging the obstruction level and showing collateral vessels. Results: Of all 28 cases, CT correctly showed the obstruction level in 26 cases, and 2 had incorrect results which proved to be membranous obstruction of the inferior vena cava superior to diaphragm. In 22 cases with hepatic vein obstructions, hepatic parenchyma displayed typical patchy enhancement in 19, atypical patchy enhancement in 3.8 cases among these showed benign nodules. Simultaneously, CT showed stenosis and rigidity of portal vein branches in 20, enlargement of hepatic artery in 14, hepatic collateral vessels in 20 out of 22 cases. In 6 cases with simple obstruction of inferior vena cava, hepatic changes were not found. Collateral circulations in or out of liver corresponded to the obstruction level. Conclusion: Dynamic enhancement examinations with multi-slice CT can correctly reflect the hepatic hemodynamic changes. Transverse images, combined with CTA, can explicitly display the obstruction level of vascular lesions and collateral circulations in BCS. (authors)

Abdominal multi-organ segmentation from CT images using conditional shape-location and unsupervised intensity priors.

Science.gov (United States)

Okada, Toshiyuki; Linguraru, Marius George; Hori, Masatoshi; Summers, Ronald M; Tomiyama, Noriyuki; Sato, Yoshinobu

2015-12-01

This paper addresses the automated segmentation of multiple organs in upper abdominal computed tomography (CT) data. The aim of our study is to develop methods to effectively construct the conditional priors and use their prediction power for more accurate segmentation as well as easy adaptation to various imaging conditions in CT images, as observed in clinical practice. We propose a general framework of multi-organ segmentation which effectively incorporates interrelations among multiple organs and easily adapts to various imaging conditions without the need for supervised intensity information. The features of the framework are as follows: (1) A method for modeling conditional shape and location (shape-location) priors, which we call prediction-based priors, is developed to derive accurate priors specific to each subject, which enables the estimation of intensity priors without the need for supervised intensity information. (2) Organ correlation graph is introduced, which defines how the conditional priors are constructed and segmentation processes of multiple organs are executed. In our framework, predictor organs, whose segmentation is sufficiently accurate by using conventional single-organ segmentation methods, are pre-segmented, and the remaining organs are hierarchically segmented using conditional shape-location priors. The proposed framework was evaluated through the segmentation of eight abdominal organs (liver, spleen, left and right kidneys, pancreas, gallbladder, aorta, and inferior vena cava) from 134 CT data from 86 patients obtained under six imaging conditions at two hospitals. The experimental results show the effectiveness of the proposed prediction-based priors and the applicability to various imaging conditions without the need for supervised intensity information. Average Dice coefficients for the liver, spleen, and kidneys were more than 92%, and were around 73% and 67% for the pancreas and gallbladder, respectively. Copyright © 2015

Prevalence of ligamentum arteriosum calcification on multi-section spiral CT and digital radiography.

Science.gov (United States)

Hong, Gil-Sun; Goo, Hyun Woo; Song, Jae-Woo

2012-06-01

To investigate the prevalence of ligamentum arteriosum calcification (LAC) on multi-section spiral CT and digital radiography. Five hundred and eight children and 232 adults who performed multi-section chest CT were included in this study and were divided into nine age groups: A (0-5 years), B (6-10 years), C (11-15 years), D (16-20 years), E (21-30 years), F (31-40 years), G (41-50 years), H (51-60 years), and I (61-70 years). Two radiologists assessed the presence of LAC on axial and coronal CT images, defined as focal calcific density on both or on one plane with attenuation >100 Hounsfield unit. The prevalence of LAC on CT was compared between children and adults, and between unenhanced and enhanced CT in children. The prevalence of LAC on digital radiography was evaluated in 476 children. The prevalence of definite LAC on unenhanced multi-section CT was significantly higher in children (37.8 %) than in adults (11.2 %) (P CT were 4.5, 12.8, 8.1, 19.0, 0.0, 0.0, 0.0, 2.0, and 1.9 %. In children, the prevalence of LAC was significantly higher on unenhanced than on enhanced CT (37.8 vs. 16.4 %, P children. LAC is frequently observed in children and adults on multi-section spiral CT, more frequently than previously reported. Compared with that on multi-section spiral CT, the prevalence of LAC on digital radiography is substantially low.

Dual- and Multi-Energy CT: Principles, Technical Approaches, and Clinical Applications

Science.gov (United States)

Leng, Shuai; Yu, Lifeng; Fletcher, Joel G.

2015-01-01

In x-ray computed tomography (CT), materials having different elemental compositions can be represented by identical pixel values on a CT image (ie, CT numbers), depending on the mass density of the material. Thus, the differentiation and classification of different tissue types and contrast agents can be extremely challenging. In dual-energy CT, an additional attenuation measurement is obtained with a second x-ray spectrum (ie, a second “energy”), allowing the differentiation of multiple materials. Alternatively, this allows quantification of the mass density of two or three materials in a mixture with known elemental composition. Recent advances in the use of energy-resolving, photon-counting detectors for CT imaging suggest the ability to acquire data in multiple energy bins, which is expected to further improve the signal-to-noise ratio for material-specific imaging. In this review, the underlying motivation and physical principles of dual- or multi-energy CT are reviewed and each of the current technical approaches is described. In addition, current and evolving clinical applications are introduced. © RSNA, 2015 PMID:26302388

Comparison of a dental cone beam CT with a multi-detector row CT on effective doses and physical image quality

International Nuclear Information System (INIS)

Yoshida, Yutaka; Tokumori, Kenji; Okamura, Kazutoshi; Yoshiura, Kazunori

2011-01-01

The purpose of this study was to compare a dental cone beam computed tomography (dental CBCT) and a multi-detector row CT (MDCT) using effective doses and physical image quality. A dental mode (D-mode) and an implant mode (I-mode) were employed for calculating effective doses. Field of view (FOV) size of the MDCT was 150 mm. Three types of images were obtained using 3 different reconstruction functions: FC1 (for abdomen images), FC30 (for internal ear and bone images) and FC81 (for high resolution images). Effective doses obtained with the D-mode and with the I-mode were about 20% and 50% of those obtained with the MDCT, respectively. Resolution properties obtained with the D-mode and I-mode were superior to that of the MDCT in a high frequency range. Noise properties of the D-mode and the I-mode were better than those with FC81. It was found that the dental CBCT has better potential as compared with MDCT in both dental and implant modes. (author)

An Automatic Multi-Target Independent Analysis Framework for Non-Planar Infrared-Visible Registration.

Science.gov (United States)

Sun, Xinglong; Xu, Tingfa; Zhang, Jizhou; Zhao, Zishu; Li, Yuankun

2017-07-26

In this paper, we propose a novel automatic multi-target registration framework for non-planar infrared-visible videos. Previous approaches usually analyzed multiple targets together and then estimated a global homography for the whole scene, however, these cannot achieve precise multi-target registration when the scenes are non-planar. Our framework is devoted to solving the problem using feature matching and multi-target tracking. The key idea is to analyze and register each target independently. We present a fast and robust feature matching strategy, where only the features on the corresponding foreground pairs are matched. Besides, new reservoirs based on the Gaussian criterion are created for all targets, and a multi-target tracking method is adopted to determine the relationships between the reservoirs and foreground blobs. With the matches in the corresponding reservoir, the homography of each target is computed according to its moving state. We tested our framework on both public near-planar and non-planar datasets. The results demonstrate that the proposed framework outperforms the state-of-the-art global registration method and the manual global registration matrix in all tested datasets.

Planar imaging quantification using 3D attenuation correction data and Monte Carlo simulated buildup factors

International Nuclear Information System (INIS)

Miller, C.; Filipow, L.; Jackson, S.; Riauka, T.

1996-01-01

A new method to correct for attenuation and the buildup of scatter in planar imaging quantification is presented. The method is based on the combined use of 3D density information provided by computed tomography to correct for attenuation and the application of Monte Carlo simulated buildup factors to correct for buildup in the projection pixels. CT and nuclear medicine images were obtained for a purpose-built nonhomogeneous phantom that models the human anatomy in the thoracic and abdominal regions. The CT transverse slices of the phantom were converted to a set of consecutive density maps. An algorithm was developed that projects the 3D information contained in the set of density maps to create opposing pairs of accurate 2D correction maps that were subsequently applied to planar images acquired from a dual-head gamma camera. A comparison of results obtained by the new method and the geometric mean approach based on published techniques is presented for some of the source arrangements used. Excellent results were obtained for various source - phantom configurations used to evaluate the method. Activity quantification of a line source at most locations in the nonhomogeneous phantom produced errors of less than 2%. Additionally, knowledge of the actual source depth is not required for accurate activity quantification. Quantification of volume sources placed in foam, Perspex and aluminium produced errors of less than 7% for the abdominal and thoracic configurations of the phantom. (author)

Time-resolved computed tomography of the liver: retrospective, multi-phase image reconstruction derived from volumetric perfusion imaging

Energy Technology Data Exchange (ETDEWEB)

Fischer, Michael A.; Kartalis, Nikolaos; Aspelin, Peter; Albiin, Nils; Brismar, Torkel B. [Karolinska University Hospital, Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden); Leidner, Bertil; Svensson, Anders [Karolinska University Hospital, Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden); Karolinska University Hospital Huddinge, Department of Radiology, Stockholm (Sweden)

2014-01-15

To assess feasibility and image quality (IQ) of a new post-processing algorithm for retrospective extraction of an optimised multi-phase CT (time-resolved CT) of the liver from volumetric perfusion imaging. Sixteen patients underwent clinically indicated perfusion CT using 4D spiral mode of dual-source 128-slice CT. Three image sets were reconstructed: motion-corrected and noise-reduced (MCNR) images derived from 4D raw data; maximum and average intensity projections (time MIP/AVG) of the arterial/portal/portal-venous phases and all phases (total MIP/ AVG) derived from retrospective fusion of dedicated MCNR split series. Two readers assessed the IQ, detection rate and evaluation time; one reader assessed image noise and lesion-to-liver contrast. Time-resolved CT was feasible in all patients. Each post-processing step yielded a significant reduction of image noise and evaluation time, maintaining lesion-to-liver contrast. Time MIPs/AVGs showed the highest overall IQ without relevant motion artefacts and best depiction of arterial and portal/portal-venous phases respectively. Time MIPs demonstrated a significantly higher detection rate for arterialised liver lesions than total MIPs/AVGs and the raw data series. Time-resolved CT allows data from volumetric perfusion imaging to be condensed into an optimised multi-phase liver CT, yielding a superior IQ and higher detection rate for arterialised liver lesions than the raw data series. (orig.)

Role of CT in Congenital Heart Disease.

Science.gov (United States)

Rajiah, Prabhakar; Saboo, Sachin S; Abbara, Suhny

2017-01-01

Congenital heart diseases (CHD) are being increasingly encountered in cardiac imaging due to improved outcomes from surgical and interventional techniques. Imaging plays an important role in the evaluation of CHD, both prior to and after surgeries and interventions. Computed tomography (CT) has several advantages in the evaluation of these disorders, particularly its high spatial resolution, multi-planar reconstruction capabilities at sub-millimeter isotropic resolution, good temporal resolution, wide field of view, and rapid turnaround time, which minimizes the need for sedation and anesthesia in young children or children with disabilities. With modern scanners, images can be acquired as fast as within one heartbeat. Although there is a risk of ionizing radiation, the radiation dose can be minimized by using several dose reduction strategies. There is a risk of contrast nephrotoxicity in patients with renal dysfunction. In this article, we will review the role of CT in the evaluation of several congenital heart diseases, both in children and adults.

- LAA Occluder View for post-implantation Evaluation (LOVE) - standardized imaging proposal evaluating implanted left atrial appendage occlusion devices by cardiac computed tomography

International Nuclear Information System (INIS)

Behnes, Michael; Akin, Ibrahim; Sartorius, Benjamin; Fastner, Christian; El-Battrawy, Ibrahim; Borggrefe, Martin; Haubenreisser, Holger; Meyer, Mathias; Schoenberg, Stefan O.; Henzler, Thomas

2016-01-01

A standardized imaging proposal evaluating implanted left atrial appendage (LAA) occlusion devices by cardiac computed tomography angiography (cCTA) has never been investigated. cCTA datasets were acquired on a 3 rd generation dual-source CT system and reconstructed with a slice thickness of 0.5 mm. An interdisciplinary evaluation was performed by two interventional cardiologists and one radiologist on a 3D multi-planar workstation. A standardized multi-planar reconstruction algorithm was developed in order to assess relevant clinical aspects of implanted LAA occlusion devices being outlined within a pictorial essay. The following clinical aspects of implanted LAA occlusion devices were evaluated within the most appropriate cCTA multi-planar reconstruction: (1) topography to neighboring structures, (2) peri-device leaks, (3) coverage of LAA lobes, (4) indirect signs of neo-endothelialization. These are illustrated within concise CT imaging examples emphasizing the potential value of the proposed cCTA imaging algorithm: Starting from anatomical cCTA planes and stepwise angulation planes perpendicular to the base of the LAA devices generates an optimal LAA Occluder View for post-implantation Evaluation (LOVE). Aligned true axial, sagittal and coronal LOVE planes offer a standardized and detailed evaluation of LAA occlusion devices after percutaneous implantation. This pictorial essay presents a standardized imaging proposal by cCTA using multi-planar reconstructions that enables systematical follow-up and comparison of patients after LAA occlusion device implantation. The online version of this article (doi:10.1186/s12880-016-0127-y) contains supplementary material, which is available to authorized users

Multi-slice spiral CT diagnosis of carotid body tumor

International Nuclear Information System (INIS)

Li Peiling; Leng Renli; Li Shu; Xie Xiuli; Xu Ke

2006-01-01

Objective: to explore the Multi-slice spiral CT (MSCT) findings of carotid body tumor (CBT). Methods: Twelve cases of CBT proved by surgery were collected in this study and all patients accepted contrast-enhanced MSCT examination. Two-dimensional and three-dimensional post-processing were performed at diagnostic workstation using Aquilion 1.42. The CT features of CBT were analyzed. Results Each of 12 patients had one lesion. All lesions demonstrated well-marginated masses of homogeneous soft- tissue density with CT value within 29-48 HU on pre-enhanced images. All lesions were markedly enhanced with CT value over 200 HU on arterial-phase images, and the density of lesions decreased rapidly on delay- phase images. Twelve lesions were all located at the level of carotid artery bifurcation, 3 of them enveloping common carotid artery and internal/external carotid artery, and other 9 of them riding right on the carotid bifurcation. Internal carotid artery usually were shifted toward posterior-lateral, and external carotid artery toward anterior or anterior-medial. Conclusion: Contrast-enhanced MSCT examination not only can make a qualitative diagnosis of CBT, but determine its accurate location. It plays an importantly instructional role in clinical diagnosis and treatment. (authors)

SPECT versus planar bone radionuclide imaging in the detection of spondylolysis

International Nuclear Information System (INIS)

Whitten, C.G.; El-Khoury, G.Y.; Chang, P.J.; Seabold, J.E.; Found, E.M.; Renfrew, D.L.

1991-01-01

This paper evaluates the relative performance and ease of interpretation of SPECT versus planar radionuclide bone imaging in the detection of spondylolysis. The authors studied all patients presenting with back pain suggestive of spondylolysis from November 1989 to January 1991 who underwent bone scanning; patients underwent both planar and SPECT imaging. The planar and SPECT images were randomly mixed and independently interpreted by four observers for presence or absence of spondylolysis and ease of interpretation for each scan. Receiver operating characteristic (ROC) and analysis of variance (ANOVA) were used. Of 72 patients, 19 had confirmed spondylolysis, and 53 did not. While ROC analysis showed that SPECT performed slightly better than planar imaging for all four observers, the difference was not statistically significant. ANOVA results suggest that planar imaging was significantly easier to use than SPECT and that ease of use was strongly correlated with the observer's confidence in the diagnosis

The current status of SPECT or SPECT/CT in South Korea

Energy Technology Data Exchange (ETDEWEB)

Yoo, Ik Dong; Choi, Eun Kyung; Chung, Yong An [Dept. of Radiology, Incheon Saint Mary' s HospitalThe Catholic University of Korea, Incheon (Korea, Republic of)

2017-06-15

The first step to nuclear medicine in Korea started with introduction of the gamma camera in 1969. Although planar images with the gamma camera give important functional information, they have the limitations that result from 2-dimensional images. Single-photon emission computed tomography (SPECT) due to its 3-dimensional image acquisition is superior to earlier planar gamma imaging in image resolution and diagnostic accuracy. As demand for a hybrid functional and anatomical imaging device has increased, integrated SPECT/CT systems have been used. In Korea, SPECT/CT was for the first time installed in 2003. SPECT/CT can eliminate many possible pitfalls on SPECT-alone images, making better attenuation correction and thereby improving image quality. Therefore, SPECT/CT is clinically preferred in many hospitals in various aspects. More recently, additional SPECT/CT images taken from the region with equivocal uptake on planar images have been helpful in making precise interpretation as part of their clinical workup in postoperative thyroid cancer patients. SPECT and SPECT/CT have various advantages, but its clinical application has gradually decreased in recent few years. While some researchers investigated the myocardial blood flow with cardiac PET using F-18 FDG or N-13 ammonia, myocardial perfusion SPECT is, at present, the radionuclide imaging study of choice for the risk stratification and guiding therapy in the coronary artery disease patients in Korea. New diagnostic radiopharmaceuticals for AD have received increasing attention; nevertheless, brain SPECT will remain the most reliable modality evaluating cerebral perfusion.

Clinical assessment of SPECT/CT co-registration image fusion

International Nuclear Information System (INIS)

Zhou Wen; Luan Zhaosheng; Peng Yong

2004-01-01

not confirmed by planner imaging were defined, 8 of them were eliminated. In 18 LUNG MAA-SPECT +CT image fusion, 10 of 11 pulmonary-embolism patients were inspected, multi-embolism patents is 8, single-embolism is 3. 8 patients of them were inspected by V/Q pulmonary planer imaging. The diagnosis for 12/18 patients were similar in LUNG MAA-SPECT +CT image fusion and V/O pulmonary planer imaging. Conclusion: Co-registration SPECT/CT image fusion could over-come the un-certain localization in single emission imaging, and avoid the deviation caused by different imaging time and space in separate - registration imaging fusion. At the moment of increasing the accuracy of location, doctors could accepted more information about anatomic, metabolism and functions. So SPECT/CT Co-registration image fusion can reject the false-positive, increase the sensibility of finding smaller foci, and enhance the veracity of diagnosis. This technical is simple , credibility and practicality, and will be have a good further for nuclear imaging in the coming years. SPECT/CT (authors)

Development of a fast multi-line x-ray CT detector for NDT

International Nuclear Information System (INIS)

Hofmann, T.; Nachtrab, F.; Schlechter, T.; Mühlbauer, J.; Schröpfer, S.; Firsching, M.; Uhlmann, N.; Neubauer, H.; Ernst, J.; Schweiger, T.; Oberst, M.; Meyer, A.

2015-01-01

Typical X-ray detectors for non-destructive testing (NDT) are line detectors or area detectors, like e.g. flat panel detectors. Multi-line detectors are currently only available in medical Computed Tomography (CT) scanners. Compared to flat panel detectors, line and multi-line detectors can achieve much higher frame rates. This allows time-resolved 3D CT scans of an object under investigation. Also, an improved image quality can be achieved due to reduced scattered radiation from object and detector themselves. Another benefit of line and multi-line detectors is that very wide detectors can be assembled easily, while flat panel detectors are usually limited to an imaging field with a size of approx. 40 × 40 cm 2 at maximum. The big disadvantage of line detectors is the limited number of object slices that can be scanned simultaneously. This leads to long scan times for large objects. Volume scans with a multi-line detector are much faster, but with almost similar image quality. Due to the promising properties of multi-line detectors their application outside of medical CT would also be very interesting for NDT. However, medical CT multi-line detectors are optimized for the scanning of human bodies. Many non-medical applications require higher spatial resolutions and/or higher X-ray energies. For those non-medical applications we are developing a fast multi-line X-ray detector.In the scope of this work, we present the current state of the development of the novel detector, which includes several outstanding properties like an adjustable curved design for variable focus-detector-distances, conserving nearly uniform perpendicular irradiation over the entire detector width. Basis of the detector is a specifically designed, radiation hard CMOS imaging sensor with a pixel pitch of 200 μ m. Each pixel has an automatic in-pixel gain adjustment, which allows for both: a very high sensitivity and a wide dynamic range. The final detector is planned to have 256 lines of

Holographic observation of magnetic resonance image CT of intracranial tumors

International Nuclear Information System (INIS)

Iwata, Kinjiro; Watanabe, Saburo; Yuasa, Hiromi; Yamada, Takahisa; Hoshino, Daisaku; Suzuki, Masane; Saito, Takayuki.

1987-01-01

In 1975, we developed a new method of 3-dimensional observation of CT pictures using Gabor's holography principle. In this study, we are reporting our experience with the multi-tomogram holography using magnetic resonance image CT in order to reconstruct 3-dimensional viewing of the central nervous system and intracranial lesions. (J.P.N.)

Efficacy of 67 gallium ECT imaging in lymphoma, infection, and lung carcinoma: A comparison with planar imaging

International Nuclear Information System (INIS)

Harwood, S.J.; Anderson, M.W.; Klein, R.C.; Friedman, B.I.; Carroll, R.G.

1984-01-01

Emission computed tomography (ECT) studies were performed on a GE 400 A/T camera and ADAC computers (system 3 and system 3300). Thirty-three sets of ECT and planar images were obtained in 20 patients over a six month period. Imaging was performed 48 hours after the intravenous administration of 5 mc of Gallium 67 citrate. No bowel preparation was employed. Comparison is made of the initial nuclear medicine report derived from planar and ECT imaging aided by clinical knowledge versus the consensus opinion of two nuclear medicine physicians reading the planar images along with minimal clinical information. The lymphoma series consists of 18 scans in 10 patients. There were 5 scans in which a false negative planar interpretation was changed to a true positive ECT interpretation. Sensitivity of planar imaging for lymphoma was 58% which rose to 100% with addition of ECT information. There were no false positives by either technique. There were 5 sets of scans in 5 lung carcinoma patients. Sensitivity of the planar images was 60% because of 2 false negative results. Sensitivity of the ECT technique was 100%. There were no false positives. The infection series consists of 10 scans in 5 patients. Sensitivity of ECT was 100%, sensitivity of planar was 66%. There was 1 false positive planar. For the total series the accuracy of planar imaging was 69% and the predictive value of a negative planar interpretation was 44%. Corresponding values for ECT imaging were 100%. The authors' experience demonstrates significant increase in sensitivity without loss of specificity resulting from the use of Emission Computed Tomography in both chest and abdomen in patients with lymphoma, infection, and lung cancer

Multi-scale analysis of lung computed tomography images

CERN Document Server

Gori, I; Fantacci, M E; Preite Martinez, A; Retico, A; De Mitri, I; Donadio, S; Fulcheri, C

2007-01-01

A computer-aided detection (CAD) system for the identification of lung internal nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 project. The three modules of our lung CAD system, a segmentation algorithm for lung internal region identification, a multi-scale dot-enhancement filter for nodule candidate selection and a multi-scale neural technique for false positive finding reduction, are described. The results obtained on a dataset of low-dose and thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.

Evaluation of the diagnostic performance of SPECT coupled to tomodensitometry (SPECT-CT) in the daily practice of bone scintigraphy at the Nuclear Medical station of Nancy

International Nuclear Information System (INIS)

Netter, F.; Journo, A.; Mayer, J.C.; Grandpierre, S.; Daragon, N.; Karcher, G.; Olivier, P.; Scigliano, S.

2008-01-01

Objective: The purpose of our study was to evaluate the diagnostic performance of SPECT coupled to computed axial tomography (SPECT- CT) in our daily practice of bone scintigraphy. Subjects and methods: SPECT- CT obtained as a complement to the planar bone scintigraphy in 39 patients were studied. Each type of image was retrospectively read by two different observers: a nuclear medicine physician who was unaware of SPECT- CT results analysed planar bone scintigraphy, a second one who was unaware of planar bone scintigraphy results analysed SPECT- CT images. In this population of patients, 17 patients were addressed in an oncologic setting. The 22 other patients were addressed for pain of indeterminate origin without neoplastic context. Results: In 13% of the cases, SPECT- CT specified the precise location of increased uptake foci seen on planar bone scintigraphy. In 38% of cases, SPECT- CT confirmed a diagnosis suspected by the planar bone scintigraphy. In 10% of cases, SPECT- CT established a diagnosis that was uncertain with planar bone scintigraphy. In 26% of cases, SPECT- CT brought no additional information. Finally in 3% of cases, SPECT- CT proved to be more sensitive than planar images. Conclusion: Our study demonstrates the utility of SPECT- CT in the daily practice of bone scintigraphy, this complementary imaging study benefited to 74% of our patients. (authors)

Hybrid imaging (SPECT/CT, PET/CT) in differentiated thyroid cancer; Imagerie hybride (TEMP/TDM, TEP/TDM) et cancer differencie de la thyroide

Energy Technology Data Exchange (ETDEWEB)

Bardet, S.; Ciappuccini, R.; Aide, N. [Unite de concertation pluridisciplinaire thyroide, service de medecine nucleaire, centre Francois-Baclesse, 14 - Caen (France); Barraux, V. [Unite de radiophysique, centre Francois-Baclesse, 14 - Caen (France); Rame, J.P. [Chirurgie ORL, centre Francois-Baclesse, 14 - Caen (France)

2010-08-15

Differentiated thyroid cancer (DTC) is generally associated with a good prognosis. Local recurrences, mainly lymph-node involvement, account for 15-20% of cases and are surgically treated. Distant metastases, mostly in lungs and more rarely in bones, are present in 5% of patients. When iodine uptake is sufficient (in approximately 60% of patients), distant metastases can be destroyed by iterative activities of iodine 131. Serum thyroglobulin (Tg), which can be assessed either on hormonal treatment or on TSH stimulation is considered as the tumour marker in DTC. Functional (iodine 131 scintigraphy, FDG PET, bone scintigraphy) or anatomical (neck ultrasound, thoracic CT, bone MRI) imaging methods can be performed when Tg increases in order to show residual/recurrent disease. In recent years, new hybrid equipments integrating both a gamma camera and CT scan (SPECT/CT) have been commercialized while positron emission tomography cameras associated with CT (PET/CT) have been installed on the whole French territory. These equipments, which allow us to directly correlate functional and anatomical images, greatly improve the interpretation of planar scintigraphy or that of PET alone. Hybrid imaging enables us to precisely localize scintigraphic foci and most often, to immediately verify whether they correspond to tumour lesions. The aim of this article is to review the role of SPECT/CT and PET/CT in the management of patients with DTC in 2010. (authors)

Accelerated magnetic resonance diffusion tensor imaging of the median nerve using simultaneous multi-slice echo planar imaging with blipped CAIPIRINHA.

Science.gov (United States)

Filli, Lukas; Piccirelli, Marco; Kenkel, David; Boss, Andreas; Manoliu, Andrei; Andreisek, Gustav; Bhat, Himanshu; Runge, Val M; Guggenberger, Roman

2016-06-01

To investigate the feasibility of MR diffusion tensor imaging (DTI) of the median nerve using simultaneous multi-slice echo planar imaging (EPI) with blipped CAIPIRINHA. After federal ethics board approval, MR imaging of the median nerves of eight healthy volunteers (mean age, 29.4 years; range, 25-32) was performed at 3 T using a 16-channel hand/wrist coil. An EPI sequence (b-value, 1,000 s/mm(2); 20 gradient directions) was acquired without acceleration as well as with twofold and threefold slice acceleration. Fractional anisotropy (FA), mean diffusivity (MD) and quality of nerve tractography (number of tracks, average track length, track homogeneity, anatomical accuracy) were compared between the acquisitions using multivariate ANOVA and the Kruskal-Wallis test. Acquisition time was 6:08 min for standard DTI, 3:38 min for twofold and 2:31 min for threefold acceleration. No differences were found regarding FA (standard DTI: 0.620 ± 0.058; twofold acceleration: 0.642 ± 0.058; threefold acceleration: 0.644 ± 0.061; p ≥ 0.217) and MD (standard DTI: 1.076 ± 0.080 mm(2)/s; twofold acceleration: 1.016 ± 0.123 mm(2)/s; threefold acceleration: 0.979 ± 0.153 mm(2)/s; p ≥ 0.074). Twofold acceleration yielded similar tractography quality compared to standard DTI (p > 0.05). With threefold acceleration, however, average track length and track homogeneity decreased (p = 0.004-0.021). Accelerated DTI of the median nerve is feasible. Twofold acceleration yields similar results to standard DTI. • Standard DTI of the median nerve is limited by its long acquisition time. • Simultaneous multi-slice acquisition is a new technique for accelerated DTI. • Accelerated DTI of the median nerve yields similar results to standard DTI.

SU-C-BRA-04: Automated Segmentation of Head-And-Neck CT Images for Radiotherapy Treatment Planning Via Multi-Atlas Machine Learning (MAML)

International Nuclear Information System (INIS)

Ren, X; Gao, H; Sharp, G

2016-01-01

Purpose: Accurate image segmentation is a crucial step during image guided radiation therapy. This work proposes multi-atlas machine learning (MAML) algorithm for automated segmentation of head-and-neck CT images. Methods: As the first step, the algorithm utilizes normalized mutual information as similarity metric, affine registration combined with multiresolution B-Spline registration, and then fuses together using the label fusion strategy via Plastimatch. As the second step, the following feature selection strategy is proposed to extract five feature components from reference or atlas images: intensity (I), distance map (D), box (B), center of gravity (C) and stable point (S). The box feature B is novel. It describes a relative position from each point to minimum inscribed rectangle of ROI. The center-of-gravity feature C is the 3D Euclidean distance from a sample point to the ROI center of gravity, and then S is the distance of the sample point to the landmarks. Then, we adopt random forest (RF) in Scikit-learn, a Python module integrating a wide range of state-of-the-art machine learning algorithms as classifier. Different feature and atlas strategies are used for different ROIs for improved performance, such as multi-atlas strategy with reference box for brainstem, and single-atlas strategy with reference landmark for optic chiasm. Results: The algorithm was validated on a set of 33 CT images with manual contours using a leave-one-out cross-validation strategy. Dice similarity coefficients between manual contours and automated contours were calculated: the proposed MAML method had an improvement from 0.79 to 0.83 for brainstem and 0.11 to 0.52 for optic chiasm with respect to multi-atlas segmentation method (MA). Conclusion: A MAML method has been proposed for automated segmentation of head-and-neck CT images with improved performance. It provides the comparable result in brainstem and the improved result in optic chiasm compared with MA. Xuhua Ren and Hao

SU-C-BRA-04: Automated Segmentation of Head-And-Neck CT Images for Radiotherapy Treatment Planning Via Multi-Atlas Machine Learning (MAML)

Energy Technology Data Exchange (ETDEWEB)

Ren, X; Gao, H [Shanghai Jiao Tong University, Shanghai, Shanghai (China); Sharp, G [Massachusetts General Hospital, Boston, MA (United States)

2016-06-15

Purpose: Accurate image segmentation is a crucial step during image guided radiation therapy. This work proposes multi-atlas machine learning (MAML) algorithm for automated segmentation of head-and-neck CT images. Methods: As the first step, the algorithm utilizes normalized mutual information as similarity metric, affine registration combined with multiresolution B-Spline registration, and then fuses together using the label fusion strategy via Plastimatch. As the second step, the following feature selection strategy is proposed to extract five feature components from reference or atlas images: intensity (I), distance map (D), box (B), center of gravity (C) and stable point (S). The box feature B is novel. It describes a relative position from each point to minimum inscribed rectangle of ROI. The center-of-gravity feature C is the 3D Euclidean distance from a sample point to the ROI center of gravity, and then S is the distance of the sample point to the landmarks. Then, we adopt random forest (RF) in Scikit-learn, a Python module integrating a wide range of state-of-the-art machine learning algorithms as classifier. Different feature and atlas strategies are used for different ROIs for improved performance, such as multi-atlas strategy with reference box for brainstem, and single-atlas strategy with reference landmark for optic chiasm. Results: The algorithm was validated on a set of 33 CT images with manual contours using a leave-one-out cross-validation strategy. Dice similarity coefficients between manual contours and automated contours were calculated: the proposed MAML method had an improvement from 0.79 to 0.83 for brainstem and 0.11 to 0.52 for optic chiasm with respect to multi-atlas segmentation method (MA). Conclusion: A MAML method has been proposed for automated segmentation of head-and-neck CT images with improved performance. It provides the comparable result in brainstem and the improved result in optic chiasm compared with MA. Xuhua Ren and Hao

Sci—Thur PM: Imaging — 06: Canada's National Computed Tomography (CT) Survey

Energy Technology Data Exchange (ETDEWEB)

Wardlaw, GM; Martel, N [Medical Imaging Division, Consumer and Clinical Radiation Protection Bureau, Healthy Environments and Consumer Safety Branch, Health Canada (Canada); Blackler, W; Asselin, J-F [Data Analysis and Information Systems, Applied Research and Analysis Directorate, Strategic Policy Branch, Health Canada (Canada)

2014-08-15

The value of computed tomography (CT) in medical imaging is reflected in its' increased use and availability since the early 1990's; however, given CT's relatively larger exposures (vs. planar x-ray) greater care must be taken to ensure that CT procedures are optimised in terms of providing the smallest dose possible while maintaining sufficient diagnostic image quality. The development of CT Diagnostic Reference Levels (DRLs) supports this process. DRLs have been suggested/supported by international/national bodies since the early 1990's and widely adopted elsewhere, but not on a national basis in Canada. Essentially, CT DRLs provide guidance on what is considered good practice for common CT exams, but require a representative sample of CT examination data to make any recommendations. Canada's National CT Survey project, in collaboration with provincial/territorial authorities, has collected a large national sample of CT practice data for 7 common examinations (with associated clinical indications) of both adult and pediatric patients. Following completion of data entry into a common database, a survey summary report and recommendations will be made on CT DRLs from this data. It is hoped that these can then be used by local regions to promote CT practice optimisation and support any dose reduction initiatives.

Choice ofoptimal phase for liver angiography and multi-phase scanning with multi-slice spiral CT

International Nuclear Information System (INIS)

Fang Hong; Song Yunlong; Bi Yongmin; Wang Dong; Shi Huiping; Zhang Wanshi; Zhu Hongxian; Yang Hua; Ji Xudong; Fan Hongxia

2008-01-01

Objective: To evaluate the efficacy of test bolus technique with multi-slice spiral CT (MSCT) for determining the optimal scan delay time in CT Hepatic artery (HA)-portal vein (PV) angiography and multi-phase scanning. Methods: MSCT liver angiography and multi-phase scanning were performed in 187 patients divided randomly into two groups. In group A (n=59), the scan delay time was set according to the subjective experiences of operators; in group B (n=128), the scan delay time was determined by test bolus technique. Abdominal aorta and superior mesenteric, vein were selected as target blood vessels, and 50 HU was set as enhancement threshold value. 20 ml contrast agent was injected intravenously and time-density curve of target blood vessels were obtained, then HA-PV scanning delay time were calculated respectively. The quality of CTA images obtained by using these 2 methods were compared and statistically analysed using Chi-square criterion. Results: For hepatic artery phase, the images of group A are: excellent in 34 (58%), good in 17 (29%), and poor in 8 (13%), while those of group B are excellent in 128(100%), good in 0(0%), and poor in 0(0%). For portal vein phase, the images of group A are: excellent in 23 (39%), good in 27 (46%), and poor in 9 (15%), while those of group B are excellent in 96 (75%), good in 28 (22%), and poor in 4 (3%) respectively. There was statistically significant difference between the ratios of image quality in group A and group B (χ 2 =14.97, 9.18, P< 0.05). Conclusion: Accurate scan delay time was best determined by using test bolus technique, which can improve the image quality of liver angiography and multi-phase scanning. (authors)

[The value of multimodal imaging by single photon emission computed tomography associated to X ray computed tomography (SPECT-CT) in the management of differentiated thyroid carcinoma: about 156 cases].

Science.gov (United States)

Mhiri, Aida; El Bez, Intidhar; Slim, Ihsen; Meddeb, Imène; Yeddes, Imene; Ghezaiel, Mohamed; Gritli, Saïd; Ben Slimène, Mohamed Faouzi

2013-10-01

Single photon emission computed tomography combined with a low dose computed tomography (SPECT-CT), is a hybrid imaging integrating functional and anatomical data. The purpose of our study was to evaluate the contribution of the SPECTCT over traditional planar imaging of patients with differentiated thyroid carcinoma (DTC). Post therapy 131IWhole body scan followed by SPECTCT of the neck and thorax, were performed in 156 patients with DTC. Among these 156 patients followed for a predominantly papillary, the use of fusion imaging SPECT-CT compared to conventional planar imaging allowed us to correct our therapeutic approach in 26.9 % (42/156 patients), according to the protocols of therapeutic management of our institute. SPECT-CT is a multimodal imaging providing better identification and more accurate anatomic localization of the foci of radioiodine uptake with impact on therapeutic management.

Feasibility of megavoltage portal CT using an electronic portal imaging device (EPID) and a multi-level scheme algebraic reconstruction technique (MLS-ART)

International Nuclear Information System (INIS)

Guan, Huaiqun; Zhu, Yunping

1998-01-01

Although electronic portal imaging devices (EPIDs) are efficient tools for radiation therapy verification, they only provide images of overlapped anatomic structures. We investigated using a fluorescent screen/CCD-based EPID, coupled with a novel multi-level scheme algebraic reconstruction technique (MLS-ART), for a feasibility study of portal computed tomography (CT) reconstructions. The CT images might be useful for radiation treatment planning and verification. We used an EPID, set it to work at the linear dynamic range and collimated 6 MV photons from a linear accelerator to a slit beam of 1 cm wide and 25 cm long. We performed scans under a total of ∼200 monitor units (MUs) for several phantoms in which we varied the number of projections and MUs per projection. The reconstructed images demonstrated that using the new MLS-ART technique megavoltage portal CT with a total of 200 MUs can achieve a contrast detectibility of ∼2.5% (object size 5mmx5mm) and a spatial resolution of 2.5 mm. (author)

Multi-slice spiral CT coronary angiography: influence of heart rate and reconstruction window on image quality

International Nuclear Information System (INIS)

Mao Dingbiao; Hua Yanqing; Wang Mingpeng; Zhang Guozhen; Wu Weilan; Hu Fei; Ge Xiaojun; Ding Qiyong

2004-01-01

Objective: To evaluate the influence of heart rate and reconstruction window on image quality of multi-slice spiral CT coronary angiography. Methods: Retrospectively ECG-gated MSCT coronary angiography were performed in 80 healthy cases. Results: Four coronary (RCA, LM, LAD, LCX) segments were analyzed in each patient with regard to image quality. 82.1% (46/56) of the coronary segments were sufficient for analysis in patients with heart rate ≤60 bpm, 63.4% (104/164) with 61-70 bpm, 41.2%(28/68) with 71-80 bpm, and 31.2%(10/32) with>80 bpm, respectively. The left anterior descending artery, left circumflex artery, and the right coronary artery were best visualized when the reconstruction window was 60%-70%, 50%-60%, and 50%-70%, respectively. Conclusion: Image quality of MSCT coronary angiography is highly dependent on heart rate and reconstruction window

Feature-based Alignment of Volumetric Multi-modal Images

Science.gov (United States)

Toews, Matthew; Zöllei, Lilla; Wells, William M.

2014-01-01

This paper proposes a method for aligning image volumes acquired from different imaging modalities (e.g. MR, CT) based on 3D scale-invariant image features. A novel method for encoding invariant feature geometry and appearance is developed, based on the assumption of locally linear intensity relationships, providing a solution to poor repeatability of feature detection in different image modalities. The encoding method is incorporated into a probabilistic feature-based model for multi-modal image alignment. The model parameters are estimated via a group-wise alignment algorithm, that iteratively alternates between estimating a feature-based model from feature data, then realigning feature data to the model, converging to a stable alignment solution with few pre-processing or pre-alignment requirements. The resulting model can be used to align multi-modal image data with the benefits of invariant feature correspondence: globally optimal solutions, high efficiency and low memory usage. The method is tested on the difficult RIRE data set of CT, T1, T2, PD and MP-RAGE brain images of subjects exhibiting significant inter-subject variability due to pathology. PMID:24683955

The Usefulness of Readout-Segmented Echo-Planar Imaging (RESOLVE) for Bio-phantom Imaging Using 3-Tesla Clinical MRI.

Science.gov (United States)

Yoshimura, Yuuki; Kuroda, Masahiro; Sugiantoc, Irfan; Bamgbosec, Babatunde O; Miyahara, Kanae; Ohmura, Yuichi; Kurozumi, Akira; Matsushita, Toshi; Ohno, Seiichiro; Kanazawa, Susumu; Asaumi, Junichi

2018-02-01

Readout-segmented echo-planar imaging (RESOLVE) is a multi-shot echo-planar imaging (EPI) modality with k-space segmented in the readout direction. We investigated whether RESOLVE decreases the distortion and artifact in the phase direction and increases the signal-to-noise ratio (SNR) in phantoms image taken with 3-tesla (3T) MRI versus conventional EPI. We used a physiological saline phantom and subtraction mapping and observed that RESOLVE's SNR was higher than EPI's. Using RESOLVE, the combination of a special-purpose coil and a large-loop coil had a higher SNR compared to using only a head/neck coil. RESOLVE's image distortioas less than EPI's. We used a 120 mM polyethylene glycol phantom to examine the phase direction artifact.vThe range where the artifact appeared in the apparent diffusion coefficient (ADC) image was shorter with RESOLVE compared to EPI. We used RESOLVE to take images of a Jurkat cell bio-phantom: the cell-region ADC was 856×10-6mm2/sec and the surrounding physiological saline-region ADC was 2,951×10-6mm2/sec. The combination of RESOLVE and the 3T clinical MRI device reduced image distortion and improved SNR and the identification of accurate ADC values due to the phase direction artifact reduction. This combination is useful for obtaining accurate ADC values of bio-phantoms.

Study of turbulent flow using Half-Fourier Echo-Planar imaging

International Nuclear Information System (INIS)

Rodriguez, A.O.

2006-01-01

The Echo-Planar Imaging technique combined with a partial Fourier acquisition method was used to obtain velocity images for liquid flows in a circular cross-section pipe at Reynolds number of up to 8000. This partial-Fourier imaging scheme is able to generate shorter echo times than the full-Fourier Echo-Planar Imaging methods, reducing the signal attenuation due to T2 * and flow. Velocity images along the z axis were acquired with a time-scale of 80 ms thus obtaining a real-time description of flow in both the laminar and turbulent regimes. Velocity values and velocity fluctuations were computed with the flow image data. A comparison plot of NMR velocity and bulk velocity and a plot of velocity fluctuations were calculated to investigate the feasibility of this imaging technique. Flow encoded Echo-Planar Imaging together with a reduced data acquisition method can provide us with a real-time technique to capture instantaneous images of the flow field for both laminar and turbulent regimes. (author)

Use of spiral CT angiography to judge central pulmonary vascular involvement from lung cancer

International Nuclear Information System (INIS)

Tan Qunyou; Zhao Shaohong; Wang Fangze; Cai Zulong

2000-01-01

Objective: To evaluate the accuracy of spiral CT angiography (SCTA) in judging central pulmonary vascular involvement from lung cancer located in the hilum and correlate the resultant images with pathologic and surgical findings. Methods: SCTA was done in 33 patients who were preoperatively diagnosed as having lung carcinoma located in the hilum. Contrast medium was injected at a rate of 3 ml/sec with a power injector. The delay time was from 20 to 25 seconds. The pitch was 1 with 3 mm-collimation. Images of central pulmonary arteries and veins were reconstructed with shaded surface display (SSD), maximum intensity projection (MIP), curved planar reformation (CPR), and multi-planar reformation (MPR). Then the relation between tumor and vessels was assessed prospectively on both 3 mm interval axial CT and SCTA images with comparison to subsequent pathologic or surgical findings. Results: (1) In showing the integrity of central pulmonary arteries and veins, images reconstructed by different ways of SCTA had different strong and weak points. (2) The grading standard in this study, with which the relation between vessels and tumor was judged, reflected the basic and common characters of central pulmonary vascular involvement by tumor located in the hilum. compared with axial CT images, SCTA was more accurate in judging the relation between central pulmonary vessels and tumor, and the correlation of SCTA imaging features with pathological patterns and surgical findings was better than that of axial CT images, P < 0.05 and P < 0.0001, respectively. Conclusion: It was feasible to show the relation between central pulmonary vessel and lung cancer located in the hilum with SCTA. And the accuracy of judging the vascular involvement with SCTA was higher than that with axial CT

Comparison of two different segmentation methods on planar lung perfusion scan with reference to quantitative value on SPECT/CT

Energy Technology Data Exchange (ETDEWEB)

Suh, Min Seok; Kang, Yeon Koo; Ha, Seung Gyun [Dept. of Nuclear Medicine, Seoul National University Hospital, Seoul (Korea, Republic of); and others

2017-06-15

Until now, there was no single standardized regional segmentation method of planar lung perfusion scan. We compared planar scan based two segmentation methods, which are frequently used in the Society of Nuclear Medicine, with reference to the lung perfusion single photon emission computed tomography (SPECT)/computed tomography (CT) derived values in lung cancer patients. Fifty-five lung cancer patients (male:female, 37:18; age, 67.8 ± 10.7 years) were evaluated. The patients underwent planar scan and SPECT/CT after injection of technetium-99 m macroaggregated albumin (Tc-99 m-MAA). The % uptake and predicted postoperative percentage forced expiratory volume in 1 s (ppoFEV1%) derived from both posterior oblique (PO) and anterior posterior (AP) methods were compared with SPECT/CT derived parameters. Concordance analysis, paired comparison, reproducibility analysis and spearman correlation analysis were conducted. The % uptake derived from PO method showed higher concordance with SPECT/CT derived % uptake in every lobe compared to AP method. Both methods showed significantly different lobar distribution of % uptake compared to SPECT/CT. For the target region, ppoFEV1% measured from PO method showed higher concordance with SPECT/CT, but lower reproducibility compared to AP method. Preliminary data revealed that every method significantly correlated with actual postoperative FEV1%, with SPECT/CT showing the best correlation. The PO method derived values showed better concordance with SPECT/CT compared to the AP method. Both PO and AP methods showed significantly different lobar distribution compared to SPECT/CT. In clinical practice such difference according to different methods and lobes should be considered for more accurate postoperative lung function prediction.

Impact of imaging quality of change pitch on coronary CTA with 64-detector row CT

International Nuclear Information System (INIS)

Li Xiang; Jin Chaolin; Zhang Shutong

2009-01-01

Objective: To investigate the impact of imaging quality of pitch on coronary CT angiography (CTA) with 64-detector row CT. Methods: 566 patients were divided into four groups according to heart rate (≤ 50, 51 ∼ 70, 71 ∼ 80 and ≥ 80 bpm). Three dimensional reconstructions were used such as volume rendering (VR), maximum intensity projection(MIP) and curved planar reformation (CPR). Each group was divided into control group and experimential group randomly, using normal pitch and revised pitch respectively, and the imaging quality and influencing factors were analyzed among the four groups. Results: There was significant difference in imaging quality among the four groups (P < 0.05). Each group had difference in imaging quality with normal pitch and revised pitch. Conclusions: The revised pitch helps to improve the imaging quality and meet the demand of diagnosis. (authors)

[Chronic pancreatitis: which is the role of 320-row CT for the staging?].

Science.gov (United States)

Stabile Ianora, Amato Antonio; Rubini, Giuseppe; Lorusso, Filomenamila; Ambriola, Angela; Rella, Leonarda; Di Crescenzo, Vincenzo; Moschetta, Marco

2013-01-01

The purpose of this study was to evaluate the diagnostic potential of multi-planar and volumetric reconstructions obtained from isotropic data by using 16-slice computed tomography (CT) in the diagnosis and staging of chronic pancreatitis. In a group of 42 patients CT images were evaluated searching for alterations in morphology and structure of the pancreas, alterations of the Wirsung duct, dilatation of the bile ducts, fluid collections, and vascular involvement of the digestive tract. The disease was then staged in mild, moderate and severe and correlated with the clinical staging. CT allowed the recognition of chronic pancreatitis in all cases. The staging was correct in 25/42 patients, with an accuracy rate of 59.5%. In the staging of moderate and severe forms, CT correlation with clinical and laboratory data was valid, but in mild forms it appeared less significant. Multi-detector CT is accurate in the recognition of moderate, advanced forms of chronic pancreatitis and in the identification of its complications, while it is poorly correlated with the clinical staging in mild forms of the disease.

CT synthesis in the head & neck region for PET/MR attenuation correction: an iterative multi-atlas approach

Energy Technology Data Exchange (ETDEWEB)

Burgos, Ninon [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Cardoso, M Jorge; Modat, Marc [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Dementia Research Centre, University College London, London (United Kingdom); Punwani, Shonit [Division of Imaging, University College London Hospitals, London (United Kingdom); Centre for Medical Imaging, University College London, London (United Kingdom); Atkinson, David [Centre for Medical Imaging, University College London, London (United Kingdom); Arridge, Simon R [Centre for Medical Image Computing, University College London, London (United Kingdom); Hutton, Brian F [Institute of Nuclear Medicine, University College London Hospitals, London (United Kingdom); Ourselin, Sébastien [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Dementia Research Centre, University College London, London (United Kingdom)

2015-05-18

In this work, we propose to tackle the problem of attenuation correction in the head and neck by synthesising CT from MR images using an iterative multi-atlas approach. The proposed method relies on pre-acquired T2-weighted MRI and CT images of the neck. For each subject, the MRI is non-rigidly mapped to the CT. To synthesise a pseudo CT, all the MRIs in the database are first registered to the target MRI. This registration consists of a robust affine followed by a non-rigid registration. The pseudo CT is obtained by fusing the mapped atlases according to their morphological similarity to the target. In contrast to CTs, T2 images do not provide a good estimate of the bone location. Combining multiple modalities at both the registration and image similarity stages is expected to provide more realistic mappings and to reduce the bias. An initial pseudo CT (pCT) is combined with the target MRI to form a MRI-pCT pair. The MRI-pCT pair is registered to all the MRI-CT pairs from the database. An improved pseudo CT is obtained by fusing the mapped MRI-CT pairs according to their morphological similarity to the target MRI-pCT pair. Results showed that the proposed CT synthesis algorithm based on a multi-atlas information propagation scheme and iterative process is able to synthesise pseudo CT images in a region challenging for registration algorithms. The results also demonstrate that the robust affine decreases the absolute error compared to the classic approach and that the bone refinement process reduces the bias in the bone region. The proposed method could be used to correct for attenuation PET/MR data, but also for dosimetry calculations in the context of MR-based radiotherapy treatment planning.

Accelerated magnetic resonance diffusion tensor imaging of the median nerve using simultaneous multi-slice echo planar imaging with blipped CAIPIRINHA

Energy Technology Data Exchange (ETDEWEB)

Filli, Lukas; Kenkel, David; Boss, Andreas; Manoliu, Andrei; Andreisek, Gustav; Runge, Val M.; Guggenberger, Roman [University Hospital of Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Piccirelli, Marco [University Hospital of Zurich, Department of Neuroradiology, Zurich (Switzerland); Bhat, Himanshu [Siemens Medical Solutions USA Inc, Charlestown, MA (United States)

2016-06-15

To investigate the feasibility of MR diffusion tensor imaging (DTI) of the median nerve using simultaneous multi-slice echo planar imaging (EPI) with blipped CAIPIRINHA. After federal ethics board approval, MR imaging of the median nerves of eight healthy volunteers (mean age, 29.4 years; range, 25-32) was performed at 3 T using a 16-channel hand/wrist coil. An EPI sequence (b-value, 1,000 s/mm{sup 2}; 20 gradient directions) was acquired without acceleration as well as with twofold and threefold slice acceleration. Fractional anisotropy (FA), mean diffusivity (MD) and quality of nerve tractography (number of tracks, average track length, track homogeneity, anatomical accuracy) were compared between the acquisitions using multivariate ANOVA and the Kruskal-Wallis test. Acquisition time was 6:08 min for standard DTI, 3:38 min for twofold and 2:31 min for threefold acceleration. No differences were found regarding FA (standard DTI: 0.620 ± 0.058; twofold acceleration: 0.642 ± 0.058; threefold acceleration: 0.644 ± 0.061; p ≥ 0.217) and MD (standard DTI: 1.076 ± 0.080 mm{sup 2}/s; twofold acceleration: 1.016 ± 0.123 mm{sup 2}/s; threefold acceleration: 0.979 ± 0.153 mm{sup 2}/s; p ≥ 0.074). Twofold acceleration yielded similar tractography quality compared to standard DTI (p > 0.05). With threefold acceleration, however, average track length and track homogeneity decreased (p = 0.004-0.021). Accelerated DTI of the median nerve is feasible. Twofold acceleration yields similar results to standard DTI. (orig.)

Slice sensitivity profiles and pixel noise of multi-slice CT in comparison with single-slice CT

International Nuclear Information System (INIS)

Schorn, C.; Obenauer, S.; Funke, M.; Hermann, K.P.; Kopka, L.; Grabbe, E.

1999-01-01

Purpose: Presentation and evaluation of slice sensitivity profile and pixel noise of multi-slice CT in comparison to single-slice CT. Methods: Slice sensitivity profiles and pixel noise of a multi-slice CT equiped with a 2D matrix detector array and of a single-slice CT were evaluated in phantom studies. Results: For the single-slice CT the width of the slice sensitivity profiles increased with increasing pitch. In spite of a much higher table speed the slice sensitivity profiles of multi-slice CT were narrower and did not increase with higher pitch. Noise in single-slice CT was independent of pitch. For multi-slice CT noise increased with higher pitch and for the higher pitch decreased slightly with higher detector row collimation. Conclusions: Multi-slice CT provides superior z-resolution and higher volume coverage speed. These qualities fulfill one of the prerequisites for improvement of 3D postprocessing. (orig.) [de

Spectral detector CT-derived virtual non-contrast images: comparison of attenuation values with unenhanced CT.

Science.gov (United States)

Ananthakrishnan, Lakshmi; Rajiah, Prabhakar; Ahn, Richard; Rassouli, Negin; Xi, Yin; Soesbe, Todd C; Lewis, Matthew A; Lenkinski, Robert E; Leyendecker, John R; Abbara, Suhny

2017-03-01

To assess virtual non-contrast (VNC) images obtained on a detection-based spectral detector CT scanner and determine how attenuation on VNC images derived from various phases of enhanced CT compare to those obtained from true unenhanced images. In this HIPAA compliant, IRB approved prospective multi-institutional study, 46 patients underwent pre- and post-contrast imaging on a prototype dual-layer spectral detector CT between October 2013 and November 2015, yielding 84 unenhanced and VNC pairs (25 arterial, 39 portal venous/nephrographic, 20 urographic). Mean attenuation was measured by one of three readers in the liver, spleen, kidneys, psoas muscle, abdominal aorta, and subcutaneous fat. Equivalence testing was used to determine if the mean difference between unenhanced and VNC attenuation was less than 5, 10, or 15 HU. VNC image quality was assessed on a 5 point scale. Mean difference between unenhanced and VNC attenuation was VNC attenuation were equivalent in all tissues except fat using a threshold of VNC overestimated the HU relative to unenhanced images. VNC image quality was rated as excellent or good in 84% of arterial phase and 85% of nephrographic phase cases, but only 40% of urographic phase. VNC images derived from novel dual layer spectral detector CT demonstrate attenuation values similar to unenhanced images in all tissues evaluated except for subcutaneous fat. Further study is needed to determine if attenuation thresholds currently used clinically for common pathology should be adjusted, particularly for lesions containing fat.

Clinical application of 16-slice spiral CT in reconstruction imaging of coronary artery for diagnosing coronary disense

International Nuclear Information System (INIS)

Mao Xinbo; Zhu Xinjin; Zeng Huiliang; Chen Xueguang

2005-01-01

Objective: An evaluation of the reconstructed imaging of coronary arteries with 16-slice spiral CT in diagnosis of coronary disease. Methods: The reconstructed images of coronary arteries obtained on a 16-slice spiral CT scanner were reviewed in 60 cases, on which the following techniques were applied: retrospective ECG-gating, Segment method with 75% R-R interval, volume rendering technique (VRT), maximum intensity projection (MIP), mulfiplanar reconstruction (MPR), curved planar reconstruction (CPR) and CT virtual endoscopy (CTVE). Results: In all 60 cases, different stages of CHD were revealed in 21 cases; none abnormality was found in 33; and images were in poor quality in 2 cases, which was available for diagnosis. There were 4 stents planted in 4 cases: soft plaque suspected in lcase, patent in 2 and occlude in 1. Conclusion: The reconstructed imaging of coronary arteries with 16-slice spiral CT is superior modality in evaluation of severe coronary stenosis, plaques, and the pantency of the intra-luminal stents, which is an efficient and non-invasive imaging in diagnosis of early-stage CHD and screening in high risk population. (authors)

Quality assurance of CT-PET alignment and image registration for radiation treatment planning

International Nuclear Information System (INIS)

Gong, S.J.; O'Keefe, G.J.; Gunawardana, D.H.

2005-01-01

A multi-layer point source phantom was first used to calibrate and verify the CT-PET system alignment. A partial whole-body Aldcrson RANDO Man Phantom (head through mid-femur) was externally and internally marked with small metal cannulas filled with 18F-FDG and then scanned with both modalities. Six series of phantom studies with different acquisition settings and scan positions were performed to reveal possible system bias and evaluate the accuracy and reliabilities of Philips Syntegra program in image alignment, coregistration and fusion. The registration error was assessed quantitatively by measuring the root-mean-square distance between the iso-centers of corresponding fiducial marker geometries in reference CT volumes and transformed CT or PET volumes. Results: Experimental data confirms the accuracy of manual, parameter, point and image-based registration using Syntegra is better than 2 mm. Comparisons between blind and cross definition of iso-centers of fiducial marks indicate that the fused CT and PET is superior to visual correlation of CT and PET side-by-side. Conclusion: In this work we demonstrate the QA procedures of Gemini image alignment and registration. Syntegra produces intrinsic and robust multi-modality image registration and fusion with careful user interaction. The registration accuracy is generally better than the spatial resolution of the PET scanner used and this appears to be sufficient for most RTP CT-PET registration procedures

CT, MRI and PET image fusion using the ProSoma 3D simulation software

International Nuclear Information System (INIS)

Dalah, E.; Bradley, D.A.; Nisbet, A.; Reise, S.

2008-01-01

Full text: Multi-modality imaging is involved in almost all oncology applications focusing on the extent of disease and target volume delineation. Commercial image fusion software packages are becoming available but require comprehensive evaluation to ensure reliability of fusion and the underpinning registration algorithm particularly for radiotherapy. The present work seeks to assess such accuracy for a number of available registration methods provided by the commercial package ProSoma. A NEMA body phantom was used in evaluating CT, MR and PET images. In addition, discussion is provided concerning the choice and geometry of fiducial markers in phantom studies and the effect of window-level on target size, in particular in regard to the application of multi modality imaging in treatment planning. In general, the accuracy of fusion of multi-modality images was within 0.5-1.5 mm of actual feature diameters and < 2 ml volume of actual values, particularly in CT images. (author)

Comparison of sequential planar {sup 177}Lu-DOTA-TATE dosimetry scans with {sup 68}Ga-DOTA-TATE PET/CT images in patients with metastasized neuroendocrine tumours undergoing peptide receptor radionuclide therapy

Energy Technology Data Exchange (ETDEWEB)

Sainz-Esteban, Aurora; Carril, Jose Manuel [Hospital Universitario Marques de Valdecilla, Department of Nuclear Medicine, Santander (Spain); Prasad, Vikas; Schuchardt, Christiane; Zachert, Carolin; Baum, Richard P. [Zentralklinik Bad Berka, Department of Nuclear Medicine and Centre for PET/CT, Bad Berka (Germany)

2012-03-15

The aim of the study was to compare sequential {sup 177}Lu-DOTA-TATE planar scans ({sup 177}Lu-DOTA-TATE) in patients with metastasized neuroendocrine tumours (NET) acquired during peptide receptor radionuclide therapy (PRRT) for dosimetry purposes with the pre-therapeutic {sup 68}Ga-DOTA-TATE positron emission tomography (PET)/CT ({sup 68}Ga-DOTA-TATE) maximum intensity projection (MIP) images obtained in the same patients concerning the sensitivity of the different methods. A total of 44 patients (59 {+-} 11 years old) with biopsy-proven NET underwent {sup 68}Ga-DOTA-TATE and {sup 177}Lu-DOTA-TATE imaging within 7.9 {+-} 7.5 days between the two examinations. {sup 177}Lu-DOTA-TATE planar images were acquired at 0.5, 2, 24, 48 and 72 h post-injection; lesions were given a score from 0 to 4 depending on the uptake of the radiopharmaceutical (0 being lowest and 4 highest). The number of tumour lesions which were identified on {sup 177}Lu-DOTA-TATE scans (in relation to the acquisition time after injection of the therapeutic dose as well as with regard to the body region) was compared to those detected on {sup 68}Ga-DOTA-TATE studies obtained before PRRT. A total of 318 lesions were detected; 280 (88%) lesions were concordant. Among the discordant lesions, 29 were {sup 68}Ga-DOTA-TATE positive and {sup 177}Lu-DOTA-TATE negative, whereas 9 were {sup 68}Ga-DOTA-TATE negative and {sup 177}Lu-DOTA-TATE positive. The sensitivity, positive predictive value and accuracy for {sup 177}Lu-DOTA-TATE as compared to {sup 68}Ga-DOTA-TATE were 91, 97 and 88%, respectively. Significantly more lesions were seen on the delayed (72 h) {sup 177}Lu-DOTA-TATE images (91%) as compared to the immediate (30 min) images (68%). The highest concordance was observed for bone metastases (97%) and the lowest for head/neck lesions (75%). Concordant lesions (n = 77; mean size 3.8 cm) were significantly larger than discordant lesions (n = 38; mean size 1.6 cm) (p < 0.05). No such significance was

Image Alignment by Piecewise Planar Region Matching

NARCIS (Netherlands)

Lou, Z.; Gevers, T.

2014-01-01

Robust image registration is a challenging problem, especially when dealing with severe changes in illumination and viewpoint. Previous methods assume a global geometric model (e.g., homography) and, hence, are only able to align images under predefined constraints (e.g., planar scenes and

FDG PET/CT for therapeutic response monitoring in multi-site non-respiratory tuberculosis

International Nuclear Information System (INIS)

Geng Tian; Yong Xiao; Bin Chen; Jun Xia; Hong Guan; Qunyi Deng

2010-01-01

Background: Tuberculosis (TB) can produce positive signals during 18 F-fluorodeoxyglucose positron emission/computed tomography (FDG PET/CT) scanning. Until now, there has been no better method than clinical assessment to evaluate the therapeutic response of non-respiratory TB (NRTB). Purpose: To retrospectively assess the ability of FDG PET/CT to evaluate the response to anti-TB treatment in patients with NRTB. Material and Methods: Three patients with multi-site NRTB underwent repeat PET/CT scans during anti-TB treatment. Changes in maximal standard uptake value (SUVmax) of the TB lesions on PET/CT images were analyzed between two scans. Initial PET/CT scans were performed before the start of anti-TB treatment, and later scans were performed after completion of the treatment. Results: Patient 1, a 63-year-old female, and patient 2, a 50-year-old male, were diagnosed as multi-site NRTB by biopsy. Patient 3, a 37-year-old male was diagnosed clinically. These patients demonstrated multiple FDG-avid lesions in whole body on initial PET/CT images. The highest SUVmax of patient 1, 2, and 3 were 13.6, 17.7, and 13.9 separately. After completion of the treatment, all positive signals of patient 1, 2, and 3 decreased to undetectable value on repeated PET/CT scans with intervals of 318 days, 258 days, and 182 days separately. Conclusion: FDG PET/CT scan may be useful for monitoring responses to anti-TB treatment in patients with NRTB

A comparative study for spatial resolution and subjective image characteristics of a multi-slice CT and a cone-beam CT for dental use

International Nuclear Information System (INIS)

Watanabe, Hiroshi; Honda, Eiichi; Tetsumura, Akemi; Kurabayashi, Tohru

2011-01-01

Purpose: Multi-slice CT (MSCT) and cone-beam CT (CBCT) are widely used in dental practice. This study compared the spatial resolution of these CT systems to elucidate which CT modalities should be selected for various clinical cases. Materials and methods: As MSCT and CBCT apparatuses, Somatom Sensation 64 and 3D Accuitomo instruments, respectively, were used. As an objective evaluation of spatial resolution of these CT systems, modulation transfer function (MTF) analysis was performed employing an over-sampling method. The results of MTF analysis were confirmed with a line-pair test using CATPHAN. As a subjective evaluation, a microstructure visualization ability study was performed using a Jcl:SD rat and a head CT phantom. Results: MTF analysis showed that for the in-plane direction, the z-axis ultrahigh resolution mode (zUHR) of the Sensation 64 and 3D Accuitomo instruments had higher spatial resolutions than the conventional mode (64x) of the Sensation 64, but for the longitudinal direction, the 3D Accuitomo had clearly higher spatial resolution than either mode of the Sensation 64. A line-pair test study and microstructure visualization ability studies confirmed the results for MTF analysis. However, images of the rat and the CT phantom revealed that the 3D Accuitomo demonstrated the failure to visualize the soft tissues along with aliasing and beam-hardening artifacts, which were not observed in the Sensation 64. Conclusions: This study successfully applied spatial resolution analysis using MSCT and CBCT systems in a comparative manner. These findings could help in deciding which CT modality should be selected for various clinical cases.

Combined SPECT/CT and PET/CT for breast imaging

Energy Technology Data Exchange (ETDEWEB)

Russo, Paolo [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy); Larobina, Michele [Istituto di Biostrutture e Bioimmagini, Consiglio Nazionale delle Ricerche, Via Tommaso De Amicis, 95, Naples I-80145 (Italy); Di Lillo, Francesca [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy); Del Vecchio, Silvana [Università di Napoli Federico II, Dipartimento di Scienze Biomediche Avanzate, Via Pansini, 5, Naples I-80131 (Italy); Mettivier, Giovanni, E-mail: mettivier@na.infn.it [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy)

2016-02-11

In the field of nuclear medicine imaging, breast imaging for cancer diagnosis is still mainly based on 2D imaging techniques. Three-dimensional tomographic imaging with whole-body PET or SPECT scanners, when used for imaging the breast, has performance limits in terms of spatial resolution and sensitivity, which can be overcome only with a dedicated instrumentation. However, only few hybrid imaging systems for PET/CT or SPECT/CT dedicated to the breast have been developed in the last decade, providing complementary functional and anatomical information on normal breast tissue and lesions. These systems are still under development and clinical trials on just few patients have been reported; no commercial dedicated breast PET/CT or SPECT/CT is available. This paper reviews combined dedicated breast PET/CT and SPECT/CT scanners described in the recent literature, with focus on their technological aspects.

The value of spiral CT scan on fracture of ankle joint and tarsal bones

International Nuclear Information System (INIS)

Li Zhaoli; Liang Jingyin; Pan Zhifeng

2009-01-01

Objective: To study the value of spiral CT scan on the fracture of ankle joint and tarsal bones. Methods: 43 cases with the fracture of ankle joint and tarsal bones were collected and analyzed. All the cases were examined by plain film radiography and spiral CT thin slice scan. Multi-planar reformation (MPR), surface shaded display (SSD) and other techniques of image post-processing were performed in 35 cases of them. Results: Spiral CT scan could demonstrate more fractures than plain film radiography in 28 cases(65.1%). There are 15 cases (34.9%) which are normal in plain film radiography but abnormal in Spiral CT scan. Spiral CT could demonstrate the different length, width, direction and number of linear low density shadow. SSD and MPR were performed again in the cases with avulsion fracture and fragmental fracture to demonstrate the fracture direction and the shape, size and location of fragments more clearly. Conclusion: Spiral CT thin slice scan with image post-processing techniques can play an important role in fracture of ankle joint and tarsal bones. (authors)

A novel APD-based detector module for multi-modality PET/SPECT/CT scanners

International Nuclear Information System (INIS)

Saoudi, A.; Lecomte, R.

1999-01-01

The lack of anatomical information in SPECT and PET images is one of the major factors limiting the ability to localize and accurately quantify radionuclide uptake in small regions of interest. This problem could be resolved by using multi-modality scanners having the capability to acquire anatomical and functional images simultaneously. The feasibility of a novel detector suitable for measuring high-energy annihilation radiation in PET, medium-energy γ-rays in SPECT and low-energy X-rays in transmission CT is demonstrated and its performance is evaluated for potential use in multi-modality PET/SPECT/CT imaging. The proposed detector consists of a thin CsI(Tl) scintillator sitting on top of a deep GSO/LSO pair read out by an avalanche photodiode. The GSO/LOS pair provides depth-of-interaction information for 511 keV detection in PET, while the thin CsI(Tl) that is essentially transparent to annihilation radiation is used for detecting lower energy X- and γ-rays. The detector performance is compared to that of an LSO/YSO phoswich. Although the implementation of the proposed GSO/LSO/CsI(Tl) detector raises special problems that increase complexity, it generally outperforms the LSO/YSO phoswich for simultaneous PET, SPECT and CT imaging

Study of Image Quality From CT Scanner Multi-Detector by using Americans College of Radiology (ACR) Phantom

Science.gov (United States)

Mulyadin; Dewang, Syamsir; Abdullah, Bualkar; Tahir, Dahlang

2018-03-01

In this study, the image quality of CT scan using phantom American College of Radiology (ACR) was determined. Scanning multidetector CT is used to know the image quality parameters by using a solid phantom containing four modules and primarily from materials that are equivalent to water. Each module is 4 cm in diameter and 20 cm in diameter. There is white alignment marks painted white to reflect the alignment laser and there are also “HEAD”, “FOOT”, and “TOP” marks on the phantom to help align. This test obtains CT images of each module according to the routine inspection protocol of the head. Acceptance of image quality obtained for determination: CT Number Accuracy (CTN), CT Number Uniformity and Noise, Linearity CT Number, Slice Technique, Low Contrast Resolution and High Contrast Resolution represent image quality parameters. In testing CT Number Accuracy (CTN), CT Uniform number and Noise are in the range of tolerable values allowed. In the test, Linearity CT Number obtained correlation value above 0.99 is the relationship between electron density and CT Number. In a low contrast resolution test, the smallest contrast groups are visible. In contrast, the high resolution is seen up to 7 lp/cm. The quality of GE CT Scan is very high, as all the image quality tests obtained are within the tolerance brackets of values permitted by the Nuclear Power Control Agency (BAPETEN). Image quality test is a way to get very important information about the accuracy of snoring result by using phantom ACR.

A unified material decomposition framework for quantitative dual- and triple-energy CT imaging.

Science.gov (United States)

Zhao, Wei; Vernekohl, Don; Han, Fei; Han, Bin; Peng, Hao; Yang, Yong; Xing, Lei; Min, James K

2018-04-21

Many clinical applications depend critically on the accurate differentiation and classi-fication of different types of materials in patient anatomy. This work introduces a unified framework for accurate nonlinear material decomposition and applies it, for the first time, in the concept of triple-energy CT (TECT) for enhanced material differentiation and classification as well as dual-energy CT METHODS: We express polychromatic projection into a linear combination of line integrals of material-selective images. The material decomposition is then turned into a problem of minimizing the least-squares difference between measured and estimated CT projections. The optimization problem is solved iteratively by updating the line integrals. The proposed technique is evaluated by using several numerical phantom measurements under different scanning protocols The triple-energy data acquisition is implemented at the scales of micro-CT and clinical CT imaging with commercial "TwinBeam" dual-source DECT configuration and a fast kV switching DECT configu-ration. Material decomposition and quantitative comparison with a photon counting detector and with the presence of a bow-tie filter are also performed. The proposed method provides quantitative material- and energy-selective images exam-ining realistic configurations for both dual- and triple-energy CT measurements. Compared to the polychromatic kV CT images, virtual monochromatic images show superior image quality. For the mouse phantom, quantitative measurements show that the differences between gadodiamide and iodine concentrations obtained using TECT and idealized photon counting CT (PCCT) are smaller than 8 mg/mL and 1 mg/mL, respectively. TECT outperforms DECT for multi-contrast CT imag-ing and is robust with respect to spectrum estimation. For the thorax phantom, the differences between the concentrations of the contrast map and the corresponding true reference values are smaller than 7 mg/mL for all of the realistic

Planar scintigraphy with 123I/99mTc-sestamibi, 99mTc-sestamibi SPECT/CT, 11C-methionine PET/CT, or selective venous sampling before reoperation of primary hyperparathyroidism?

Science.gov (United States)

Schalin-Jäntti, Camilla; Ryhänen, Eeva; Heiskanen, Ilkka; Seppänen, Marko; Arola, Johanna; Schildt, Jukka; Väisänen, Mika; Nelimarkka, Lassi; Lisinen, Irina; Aalto, Ville; Nuutila, Pirjo; Välimäki, Matti J

2013-05-01

All patients with primary hyperparathyroidism should undergo localization studies before reoperation, but it is not known which method is most accurate. The purpose of this prospective study was to compare the performance of planar scintigraphy with (123)I/(99m)Tc-sestamibi, (99m)Tc-sestamibi SPECT (SPECT/CT), (11)C-methionine PET/CT, and selective venous sampling (SVS) in persistent primary hyperparathyroidism. Twenty-one patients referred for reoperation of persistent hyperparathyroidism were included and investigated with (123)I/(99m)Tc-sestamibi, SPECT/CT (n = 19), (11)C-methionine PET/CT, and SVS (n = 18) before reoperation. All patients had been operated on 1-2 times previously because of hyperparathyroidism. The results of the localization studies were compared with operative findings, histology, and biochemical cure. Eighteen (86%) of 21 patients were biochemically cured. Nineteen parathyroid glands (9 adenomas, 1 atypical adenoma, and 9 hyperplastic glands) were removed from 17 patients, and 1 patient who was biochemically cured had an unclear histology result. The accuracy for localizing a pathologic parathyroid gland to the correct side of the neck was 59% (95% confidence interval [CI], 36%-79%) for (123)I/(99m)Tc-sestamibi, 19% (95% CI, 5%-42%) for SPECT/CT, 65% (95% CI, 43%-84%) for (11)C-methionine PET/CT, and 40% (95% CI, 19%-65%) for SVS (P hyperparathyroidism and is recommended as first-line imaging before reoperation. (11)C-methionine PET/CT provides valuable additional information if (123)I/(99m)Tc-sestamibi scan results remain negative. (99m)Tc-sestamibi SPECT/CT and SVS provide no additional information, compared with the combined results of (123)I/(99m)Tc-sestamibi and (11)C-methionine PET/CT imaging.

Congenital heart diseases: post-operative appearance on multi-detector CT - a pictorial essay

Energy Technology Data Exchange (ETDEWEB)

Tomasian, Anderanik; Malik, Sachin; Shamsa, Kamran; Krishnam, Mayil S. [UCLA Medical Center, Department of Radiological Science, Los Angeles, CA (United States)

2009-12-15

Echocardiography is considered as an initial imaging modality of choice in patients with congenital heart disease (CHD), and magnetic resonance (MR) imaging is preferred for detailed functional information. Multi-detector computed tomography (CT) plays an important role in clinical practice in assessing post-operative morphological and functional information of patients with complex CHD when echocardiography and MR imaging are not contributory. Radiologists should understand and become familiar with the complex morphology and physiology of CHD, as well as with various palliative and corrective surgical procedures performed in these patients, to obtain CT angiograms with diagnostic quality and promptly recognise imaging features of normal post-operative anatomy and complications of these complex surgeries. (orig.)

Spectroscopic (multi-energy) CT distinguishes iodine and barium contrast material in MICE

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Anderson, N.G. [University of Otago, Department of Radiology, Christchurch (New Zealand); Butler, A.P. [University of Otago, Department of Radiology, Christchurch (New Zealand); University of Canterbury, Physics and Astronomy, Christchurch (New Zealand); Scott, N.J.A. [University of Otago, Department of Medicine, Christchurch (New Zealand); Cook, N.J. [Christchurch Hospital, Medical Physics and Bioengineering, Christchurch (New Zealand); Butzer, J.S. [Karlsruhe Institute of Technology, Physics Department, Karlsruhe (Germany); Schleich, N. [University of Canterbury, Physics and Astronomy, Christchurch (New Zealand); Christchurch Hospital, Medical Physics and Bioengineering, Christchurch (New Zealand); Firsching, M. [Friedrich Alexander University, Physics Department, Erlangen (Germany); Grasset, R.; Ruiter, N. de [University of Canterbury, Hitlab NZ, Christchurch (New Zealand); Campbell, M. [European Organisation for Nuclear Research, Physics Section, Geneva (Switzerland); Butler, P.H. [University of Canterbury, Physics and Astronomy, Christchurch (New Zealand)

2010-09-15

Spectral CT differs from dual-energy CT by using a conventional X-ray tube and a photon-counting detector. We wished to produce 3D spectroscopic images of mice that distinguished calcium, iodine and barium. We developed a desktop spectral CT, dubbed MARS, based around the Medipix2 photon-counting energy-discriminating detector. The single conventional X-ray tube operated at constant voltage (75 kVp) and constant current (150 {mu}A). We anaesthetised with ketamine six black mice (C57BL/6). We introduced iodinated contrast material and barium sulphate into the vascular system, alimentary tract and respiratory tract as we euthanised them. The mice were preserved in resin and imaged at four detector energy levels from 12 keV to 42 keV to include the K-edges of iodine (33.0 keV) and barium (37.4 keV). Principal component analysis was applied to reconstructed images to identify components with independent energy response, then displayed in 2D and 3D. Iodinated and barium contrast material was spectrally distinct from soft tissue and bone in all six mice. Calcium, iodine and barium were displayed as separate channels on 3D colour images at <55 {mu}m isotropic voxels. Spectral CT distinguishes contrast agents with K-edges only 4 keV apart. Multi-contrast imaging and molecular CT are potential future applications. (orig.)

SU-E-I-100: Heterogeneity Studying for Primary and Lymphoma Tumors by Using Multi-Scale Image Texture Analysis with PET-CT Images

Energy Technology Data Exchange (ETDEWEB)

Li, Dengwang [Shandong Normal University, Jinan, Shandong Province (China); Wang, Qinfen [Shandong Normal University, Jinan, Shandong (China); Li, H; Chen, J [Shandong Cancer Hospital and Institute, Jinan, Shandong (China)

2014-06-01

Purpose: The purpose of this research is studying tumor heterogeneity of the primary and lymphoma by using multi-scale texture analysis with PET-CT images, where the tumor heterogeneity is expressed by texture features. Methods: Datasets were collected from 12 lung cancer patients, and both of primary and lymphoma tumors were detected with all these patients. All patients underwent whole-body 18F-FDG PET/CT scan before treatment.The regions of interest (ROI) of primary and lymphoma tumor were contoured by experienced clinical doctors. Then the ROI of primary and lymphoma tumor is extracted automatically by using Matlab software. According to the geometry size of contour structure, the images of tumor are decomposed by multi-scale method.Wavelet transform was performed on ROI structures within images by L layers sampling, and then wavelet sub-bands which have the same size of the original image are obtained. The number of sub-bands is 3L+1.The gray level co-occurrence matrix (GLCM) is calculated within different sub-bands, thenenergy, inertia, correlation and gray in-homogeneity were extracted from GLCM.Finally, heterogeneity statistical analysis was studied for primary and lymphoma tumor using the texture features. Results: Energy, inertia, correlation and gray in-homogeneity are calculated with our experiments for heterogeneity statistical analysis.Energy for primary and lymphomatumor is equal with the same patient, while gray in-homogeneity and inertia of primaryare 2.59595±0.00855, 0.6439±0.0007 respectively. Gray in-homogeneity and inertia of lymphoma are 2.60115±0.00635, 0.64435±0.00055 respectively. The experiments showed that the volume of lymphoma is smaller than primary tumor, but thegray in-homogeneity and inertia were higher than primary tumor with the same patient, and the correlation with lymphoma tumors is zero, while the correlation with primary tumor isslightly strong. Conclusion: This studying showed that there were effective heterogeneity

SPECT/CT and pulmonary embolism

Energy Technology Data Exchange (ETDEWEB)

Mortensen, Jann [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); The Faroese National Hospital, Department of Medicine, Torshavn (Faroe Islands); Gutte, Henrik [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Herlev Hospital, Copenhagen University Hospital, Department of Radiology, Copenhagen (Denmark); University of Copenhagen, Cluster for Molecular Imaging, Faculty of Health Sciences, Copenhagen (Denmark)

2014-05-15

Acute pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/P) scintigraphy or pulmonary CT angiography (CTPA). In recent years both techniques have improved. Many nuclear medicine centres have adopted the single photon emission CT (SPECT) technique as opposed to the planar technique for diagnosing PE. SPECT has been shown to have fewer indeterminate results and a higher diagnostic value. The latest improvement is the combination of a low-dose CT scan with a V/P SPECT scan in a hybrid tomograph. In a study comparing CTPA, planar scintigraphy and SPECT alone, SPECT/CT had the best diagnostic accuracy for PE. In addition, recent developments in the CTPA technique have made it possible to image the pulmonary arteries of the lungs in one breath-hold. This development is based on the change from a single-detector to multidetector CT technology with an increase in volume coverage per rotation and faster rotation. Furthermore, the dual energy CT technique is a promising modality that can provide functional imaging in combination with anatomical information. Newer high-end CT scanners and SPECT systems are able to visualize smaller subsegmental emboli. However, consensus is lacking regarding the clinical impact and treatment. In the present review, SPECT and SPECT in combination with low-dose CT, CTPA and dual energy CT are discussed in the context of diagnosing PE. (orig.)

Panoramic three-dimensional CT imaging

International Nuclear Information System (INIS)

Kawamata, Akitoshi; Fujishita, Masami

1998-01-01

Panoramic radiography is a unique projection technique for producing a single image of both maxillary and mandibular arches and many other anatomical structures. To obtain a similar panoramic image without panoramic radiography system, a modified three-dimensional (3D) CT imaging technique was designed. A set of CT slice image data extending from the chin to the orbit was used for 3D reconstruction. The CT machine used in this study was the X-Vision (TOSHIBA, Japan). The helical scan technique was used. The slice thickness of reconstructed image was one or 1.5 mm. The occlusal plane or Frankfort horizontal (FH) plane was used as the reference line. The resultant slice image data was stored on a magnetic optical disk and then used to create panoramic 3D-CT images on a Macintosh computer systems (Power Macintosh 8600/250, Apple Computer Inc., USA). To create the panoramic 3D-CT image, the following procedure was designed: Design a curved panoramic 3D-CT imaging layer using the imaging layer and the movement of the x-ray beam in panoramic radiography system as a template; Cut this imaging layer from each slice image, then the trimmed image was transformed to a rectangular layer using the ''still image warping'' special effect in the Elastic Reality special effects system (Elastic Reality Inc., USA); Create panoramic 3D-CT image using the Voxel View (Vital Images Inc., USA) rendering system and volume rendering technique. Although the image quality was primitive, a panoramic view of maxillofacial region was obtained by this technique. (author)

Multi-Modality Medical Image Fusion Based on Wavelet Analysis and Quality Evaluation

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Multi-modality medical image fusion has more and more important applications in medical image analysisand understanding. In this paper, we develop and apply a multi-resolution method based on wavelet pyramid to fusemedical images from different modalities such as PET-MRI and CT-MRI. In particular, we evaluate the different fusionresults when applying different selection rules and obtain optimum combination of fusion parameters.

Three-dimensional versus conventional CT in the evaluation of facial trauma

International Nuclear Information System (INIS)

Mayer, J.S.; Yeakley, J.W.; Kulkarni, M.V.; Wainwright, D.J.; Lee, K.F.; Harris, J.H. Jr.

1987-01-01

An accurate knowledge of the three-dimensional pattern of facial fractures is surgically important. This exhibit shows how this may be difficult if not impossible to obtain using axial and reconstructed CT images and how 3D CT is superior in this regard. 3D CT displays the course of anterior and lateral facial fractures and the spatial orientation of bone fragments that can be missed when using other CT techniques. 3D CT and facial CT images can be generated from a single CT examination and are complementary. Together they display posttraumatic facial anatomy better than conventional planar CT images

Comparison of image quality in head CT studies with different dose-reduction strategies

DEFF Research Database (Denmark)

Johansen, Jeppe; Nielsen, Rikke; Fink-Jensen, Vibeke

The number of multi-detector CT examinations is increasing rapidly. They allow high quality reformatted images providing accurate and precise diagnosis at maximum speed. Brain examinations are the most commonly requested studies, and although they come at a lower effective dose than body CT, can...... account to a considerable radiation dose as many patients undergo repeated studies. Therefore, various dose-reduction strategies are applied such as automated tube current and voltage modulation and recently different iterative reconstruction algorithms. However, the trade-off of all dose......-reduction maneuvers is reduction of image quality due to image noise or artifacts. The aim of our study was therefore to find the best diagnostic images with lowest possible dose. We present results of dose- and image quality optimizing strategies of brain CT examinations at our institution. We compare sequential...

Spect-CT and PET: CT in the management of differentiated thyroid cancer

International Nuclear Information System (INIS)

Khan, Shoukat H.

2007-01-01

Full text: With the advancement and evolution in medical technology notably imaging there has been a sea change in the overall management strategy of most of the cancers of human body. The present day functional, imaging with PET and MRI enables us to pick up a tumour at its cellular stage. Molecular imaging and nanotechnology have further added to this expanding armamentarium of cancer imaging and treatment. Thyroid cancer is one such cancer where the cutting edge biotechnology has dramatically changed the management profile of a disease. Thyroid cancer can safely be classified as one of the cancers which if optimally managed is curable. Hybrid and fusion imaging like SPECT-CT and PET-CT with their superior sensitivity and specificity have greatly improved the accuracy of disease detection and reduced drastically the false positive disease sites. Disease not detected by conventional planar imaging can now be detected and also anatomically localized using hybrid imaging modalities of SPECT-CT and PET-CT. An accurate detection and precise localization improves image interpretation and a treatment optimization in the curable cancer of thyroid

A pilot study of three dimensional color CT images of brain diseases to improve informed consent

International Nuclear Information System (INIS)

Tanizaki, Yoshio; Akiyama, Takenori; Hiraga, Kenji; Akaji, Kazunori

2005-01-01

We have described brain diseases to patients and their family using monochrome CT images. It is thought that patients have difficulties in giving their consent to our conventional explanation because their understanding of brain diseases is based on three dimensional and color images, however, standard CT images are two dimensional and gray scale images. We have been trying to use three dimensional color CT images to improve the typical patient's comprehension of brain diseases. We also try to simulate surgery using these images. Multi-slice CT accumulates precise isotropic voxel data within a half minute. These two dimensional and monochrome data are converted to three dimensional color CT images by 3D workstation. Three dimensional color CT images of each brain structures (e.g. scalp, skull, brain, ventricles and lesions) are created separately. Then, selected structures are fused together for different purposes. These images are able to rotate around any axis. Because the methods to generate three-dimensional color images have not established, we neurosurgeons must create these images. In particular, when an operation is required, the surgeon should create the images. In this paper, we demonstrate how three-dimensional color CT images can improve informed consent. (author)

ADDITIONAL VALUE OF POST-THERAPY 131 I SPECT/CT IN PATIENTS WITH DIFFERENTIATED THYROID CANCER

Directory of Open Access Journals (Sweden)

Satyawati Deswal

2017-03-01

Full Text Available BACKGROUND Generally, it is seen that SPECT/CT images are more useful than the planar images. We compared post-therapy 131 I imaging findings on planar and SPECT/CT scans to assess the clinical utility of SPECT/CT in management of patients with differentiated thyroid cancer. MATERIALS AND METHODS Post-therapy imaging was performed at 4-7 (when 5mR/hrs. exposure rate were observed by the survey meter days after 131 I administration and all patients underwent whole-body scintigraphy and SPECT/CT scanning on the same day. A generalised McNemar 1 was used to determine to establish the agreement between planar whole-body imaging and SPECT/CT for the assignment of benign, equivocal and malignant findings. RESULTS In 44 patients, 32 of the 44 patients underwent postsurgical 131 I ablation of residual thyroid tissue and 12 of 44 patients, 2 patients were treated twice. Hence, a total of 46 scans were analysed. SPECT/CT helped to localise focal iodine uptake and characterise it as either normal or abnormal thereby reducing the need for additional imaging studies. In post-thyroidectomy patients, SPECT/CT findings affected the ATA risk classification with implications for management by changing the interval for clinical followup and the need for additional imaging and laboratory tests. Our study found an 11% change in nodal status in the postsurgical group. Change in patient management was observed in 18%. CONCLUSION SPECT/CT enabled more accurate characterisation of focal iodine accumulation in patients.

Diagnostic value of radionuclide imaging combined with routine CT in detecting hepatic focal nodular hyperplasia

International Nuclear Information System (INIS)

Lu Xuemin; Yu Shuhong; Han Jiankui

2011-01-01

Objective: To investigate radionuclide imaging and routine CT in diagnosing hepatic focal nodular hyperplasia (FNH) and the combined diagnostic value of the two modalities. Methods: Thirty-two patients with hepatic FNH were retrospectively studied. All patients underwent routine CT scan. Twenty-four patients were examined by 99 Tc m -sulfur colloid (SC) hepatic planar scintigraphy and SPECT/CT imaging, and then patients who had abnormal foci underwent 99 Tc m -diethyl iminodiacetic acid (EHIDA) triple-phase hepatobiliary imaging. χ 2 -test of four-table or Fisher exact probabilities in 2 × 2 table was applied for statistical analysis. Results: Of all 32 patients pathologically diagnosed as FNH with single solitary nodule, 25 were classified as classic type and the rest 7 as non-classic type. Although routine CT found all hepatic lesions, only 15 cases were diagnosed pathologically as FNH classic type but the rest were either misdiagnosed or left as indeterminate. On radionuclide imaging (hepatic colloid scintigraphy plus triple-phase hepatobiliary images), 11 patients with big foci (with maximal diameter >3 cm) out of 24 patients were correctly diagnosed as FNH, with 7 diagnosed as classic type FNH and 4 as non-classic. Other 13 patients were either misdiagnosed or simply missed. The diagnosing rates of routine CT and radionuclide imaging were 60.0% (15/25) and 38.9% (7/18) for FNH classic type, 0/7 and 4/6 for non-classic type, 50.0% (10/20) and 73.3% (11/15) for big foci, 41.7% (5/12) and 0/9 for small foci (with maximal diameter ≤3 cm), respectively. The total diagnosing rate of radionuclide imaging combined with routine CT was significantly higher than that of routine CT or radionuclide imaging alone (χ 2 =4.48, P<0.05; χ 2 =4.27, P<0.05). Conclusion: Radionuclide imaging in combination with routine CT may improve the diagnostic accuracy for hepatic FNH patients. (authors)

Subtraction imaging of the ECG gated cardiac CT

Energy Technology Data Exchange (ETDEWEB)

Tanegashima, K.; Fukui, M.; Hyodo, H.

1987-05-01

The subtracting manipulation of contrast-enhanced gated cardiac CT (GCCT) images was experimentally studied with TCT 60A - 30 type (Toshiba) for clinical use, thereby reducing the amount of contrast medium (CM). Initially the optimum relationship between the concentration of CM and its injected velocity was determined using the model of resected canine hearts and in actual dogs. The emphasized good-subtracted images were obtained when the difference of CT values was approximately 40 H.U. between cardiac cavity and myocardium. Such condition was feasible in the use of 25 % Diatrizoic acid and its injected velocity of 0.02 ml/kg/sec. Finally the reduction of the amount of CM by 1/3 became possible in clinical settings. The method is applicable to multi-slice GCCT in various heart diseases.

Nuclear Medicine Imaging Devices. Chapter 11

Energy Technology Data Exchange (ETDEWEB)

Lodge, M. A.; Frey, E. C. [Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD (United States)

2014-12-15

Imaging forms an important part of nuclear medicine and a number of different imaging devices have been developed. This chapter describes the principles and technological characteristics of the main imaging devices used in nuclear medicine. The two major categories are gamma camera systems and positron emission tomography (PET) systems. The former are used to image γ rays emitted by any nuclide, while the latter exploit the directional correlation between annihilation photons emitted by positron decay. The first section of this chapter discusses the principal components of gamma cameras and how they are used to form 2-D planar images as well as 3-D tomographic images (single photon emission computed tomography (SPECT)). The second section describes related instrumentation that has been optimized for PET data acquisition. A major advance in nuclear medicine was achieved with the introduction of multi-modality imaging systems including SPECT/computed tomography (CT) and PET/CT. In these systems, the CT images can be used to provide an anatomical context for the functional nuclear medicine images and allow for attenuation compensation. The third section in this chapter provides a discussion of the principles of these devices.

CT imaging features of anaplastic thyroid carcinoma

International Nuclear Information System (INIS)

Shi Zhenshan; You Ruixiong; Cao Dairong; Li Yueming; Zhuang Qian

2013-01-01

Objective: To investigate the CT characteristics of anaplastic thyroid carcinoma and evaluate the diagnostic value of CT in this disease. Methods: The CT findings of 10 patients with pathologically proved anaplastic thyroid carcinoma were retrospectively reviewed. The patients included 7 females and 3 males. Their age ranged from 25.0 to 78 years with median of 61 years. Multi-slices plain and post contrast CT scans were performed in all patients. Results: Unilateral thyroid was involved in 6 patients. Unilateral thyroid and thyroid isthmus were both involved in 2 patients due to big size. Bilateral thyroid were involved in 2 patients. The maximum diameter of anaplastic thyroid carcinoma ranged from 2.9-12.8 cm with mean of (4.5 ± 1.4) cm. All lesions demonstrated unclear margins and envelope invasion. The densities of all lesions were heterogeneous and obvious necrosis areas were noted on precontrast images. Seven lesions showed varied calcifications, and coarse granular calcifications were found in 5 lesions among them. All lesions showed remarkable heterogenous enhancement on post-contrast CT. The CT value of solid portion of the tumor increased 40 HU after contrast media administration. The ratios of CT value which comparing of the tumor with contralateral sternocleidomastoid muscle were 0.69-0.82 (0.76 ± 0.18) and 1.25-1.41 (1.33 ± 0.28) on pre and post CT, respectively. Enlarged cervical lymph nodes were found in 6 cases (60.0%). It showed obvious homogeneous enhancement or irregular ring-like enhancement on post-contrast images and dot calcifications were seen in 1 case. Conclusions: Relative larger single thyroid masses with coarse granular calcifications, necrosis,envelope invasion, remarkable heterogeneous enhancing and enlarged lymph nodes on CT are suggestive of anaplastic thyroid carcinoma. (authors)

Volumetric CT-images improve testing of radiological image interpretation skills

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Ravesloot, Cécile J., E-mail: C.J.Ravesloot@umcutrecht.nl [Radiology Department at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, Room E01.132 (Netherlands); Schaaf, Marieke F. van der, E-mail: M.F.vanderSchaaf@uu.nl [Department of Pedagogical and Educational Sciences at Utrecht University, Heidelberglaan 1, 3584 CS Utrecht (Netherlands); Schaik, Jan P.J. van, E-mail: J.P.J.vanSchaik@umcutrecht.nl [Radiology Department at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, Room E01.132 (Netherlands); Cate, Olle Th.J. ten, E-mail: T.J.tenCate@umcutrecht.nl [Center for Research and Development of Education at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht (Netherlands); Gijp, Anouk van der, E-mail: A.vanderGijp-2@umcutrecht.nl [Radiology Department at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, Room E01.132 (Netherlands); Mol, Christian P., E-mail: C.Mol@umcutrecht.nl [Image Sciences Institute at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht (Netherlands); Vincken, Koen L., E-mail: K.Vincken@umcutrecht.nl [Image Sciences Institute at University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht (Netherlands)

2015-05-15

Rationale and objectives: Current radiology practice increasingly involves interpretation of volumetric data sets. In contrast, most radiology tests still contain only 2D images. We introduced a new testing tool that allows for stack viewing of volumetric images in our undergraduate radiology program. We hypothesized that tests with volumetric CT-images enhance test quality, in comparison with traditional completely 2D image-based tests, because they might better reflect required skills for clinical practice. Materials and methods: Two groups of medical students (n = 139; n = 143), trained with 2D and volumetric CT-images, took a digital radiology test in two versions (A and B), each containing both 2D and volumetric CT-image questions. In a questionnaire, they were asked to comment on the representativeness for clinical practice, difficulty and user-friendliness of the test questions and testing program. Students’ test scores and reliabilities, measured with Cronbach's alpha, of 2D and volumetric CT-image tests were compared. Results: Estimated reliabilities (Cronbach's alphas) were higher for volumetric CT-image scores (version A: .51 and version B: .54), than for 2D CT-image scores (version A: .24 and version B: .37). Participants found volumetric CT-image tests more representative of clinical practice, and considered them to be less difficult than volumetric CT-image questions. However, in one version (A), volumetric CT-image scores (M 80.9, SD 14.8) were significantly lower than 2D CT-image scores (M 88.4, SD 10.4) (p < .001). The volumetric CT-image testing program was considered user-friendly. Conclusion: This study shows that volumetric image questions can be successfully integrated in students’ radiology testing. Results suggests that the inclusion of volumetric CT-images might improve the quality of radiology tests by positively impacting perceived representativeness for clinical practice and increasing reliability of the test.

The Role of Multi-slice Spiral CT Angiography in Patient Management After Endovascular Therapy

International Nuclear Information System (INIS)

Peloschek, P.; Sailer, J.; Loewe, C.; Schillinger, M.; Lammer, J.

2006-01-01

Objectives. To bring out the role of multi-slice spiral CT angiography (MS-CTA) in patient management after endovascular therapy of subclavian artery stenosis. Methods. Twenty-one consecutive patients with clinically suspected restenosis after endovascular treatment of subclavian artery stenosis or occlusion were included in the study. Eleven patients had been treated with percutaneous transluminal angioplasty (PTA) alone and 10 with PTA and stenting. The mean follow-up period after PTA or stenting was 57 (±27 SD) months. CTA was performed using a bolus-triggered high-resolution protocol with biphasic intravenous contrast medium injection. Axial images and curved planar reformations (CPRs) were rated by three readers with regard to patency of supra-aortic vessels. Imaging findings were correlated with a standardized clinical assessment. Results. All examinations were of diagnostic quality. Of 21 referred patients, 7 had significant reobstruction of the treated subclavian artery. Six of the 7 patients with significant restenosis on CTA were treated conservatively (antiplatelet agents), despite 2 of them being symptomatic on the standardized clinical assessment, which showed a sensitivity and specificity of 86% in predicting stenosis. One patient was treated with PTA and stent deployment because of strong subjective suffering. Conclusion. MS-CTA is useful for exclusion or quantification of clinically suspected restenosis in carefully selected patients after endovascular therapy where ultrasound is inconclusive and/or contrast-enhanced magnetic resonance angiography is contraindicated

Image Guided Radiation Therapy Using Synthetic Computed Tomography Images in Brain Cancer

Energy Technology Data Exchange (ETDEWEB)

Price, Ryan G. [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan (United States); Kim, Joshua P.; Zheng, Weili [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Chetty, Indrin J. [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan (United States); Glide-Hurst, Carri, E-mail: churst2@hfhs.org [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan (United States)

2016-07-15

Purpose: The development of synthetic computed tomography (CT) (synCT) derived from magnetic resonance (MR) images supports MR-only treatment planning. We evaluated the accuracy of synCT and synCT-generated digitally reconstructed radiographs (DRRs) relative to CT and determined their performance for image guided radiation therapy (IGRT). Methods and Materials: Magnetic resonance simulation (MR-SIM) and CT simulation (CT-SIM) images were acquired of an anthropomorphic skull phantom and 12 patient brain cancer cases. SynCTs were generated using fluid attenuation inversion recovery, ultrashort echo time, and Dixon data sets through a voxel-based weighted summation of 5 tissue classifications. The DRRs were generated from the phantom synCT, and geometric fidelity was assessed relative to CT-generated DRRs through bounding box and landmark analysis. An offline retrospective analysis was conducted to register cone beam CTs (n=34) to synCTs and CTs using automated rigid registration in the treatment planning system. Planar MV and KV images (n=37) were rigidly registered to synCT and CT DRRs using an in-house script. Planar and volumetric registration reproducibility was assessed and margin differences were characterized by the van Herk formalism. Results: Bounding box and landmark analysis of phantom synCT DRRs were within 1 mm of CT DRRs. Absolute planar registration shift differences ranged from 0.0 to 0.7 mm for phantom DRRs on all treatment platforms and from 0.0 to 0.4 mm for volumetric registrations. For patient planar registrations, the mean shift differences were 0.4 ± 0.5 mm (range, −0.6 to 1.6 mm), 0.0 ± 0.5 mm (range, −0.9 to 1.2 mm), and 0.1 ± 0.3 mm (range, −0.7 to 0.6 mm) for the superior-inferior (S-I), left-right (L-R), and anterior-posterior (A-P) axes, respectively. The mean shift differences in volumetric registrations were 0.6 ± 0.4 mm (range, −0.2 to 1.6 mm), 0.2 ± 0.4 mm (range, −0.3 to 1.2 mm), and 0.2 ± 0

Image Guided Radiation Therapy Using Synthetic Computed Tomography Images in Brain Cancer

International Nuclear Information System (INIS)

Price, Ryan G.; Kim, Joshua P.; Zheng, Weili; Chetty, Indrin J.; Glide-Hurst, Carri

2016-01-01

Purpose: The development of synthetic computed tomography (CT) (synCT) derived from magnetic resonance (MR) images supports MR-only treatment planning. We evaluated the accuracy of synCT and synCT-generated digitally reconstructed radiographs (DRRs) relative to CT and determined their performance for image guided radiation therapy (IGRT). Methods and Materials: Magnetic resonance simulation (MR-SIM) and CT simulation (CT-SIM) images were acquired of an anthropomorphic skull phantom and 12 patient brain cancer cases. SynCTs were generated using fluid attenuation inversion recovery, ultrashort echo time, and Dixon data sets through a voxel-based weighted summation of 5 tissue classifications. The DRRs were generated from the phantom synCT, and geometric fidelity was assessed relative to CT-generated DRRs through bounding box and landmark analysis. An offline retrospective analysis was conducted to register cone beam CTs (n=34) to synCTs and CTs using automated rigid registration in the treatment planning system. Planar MV and KV images (n=37) were rigidly registered to synCT and CT DRRs using an in-house script. Planar and volumetric registration reproducibility was assessed and margin differences were characterized by the van Herk formalism. Results: Bounding box and landmark analysis of phantom synCT DRRs were within 1 mm of CT DRRs. Absolute planar registration shift differences ranged from 0.0 to 0.7 mm for phantom DRRs on all treatment platforms and from 0.0 to 0.4 mm for volumetric registrations. For patient planar registrations, the mean shift differences were 0.4 ± 0.5 mm (range, −0.6 to 1.6 mm), 0.0 ± 0.5 mm (range, −0.9 to 1.2 mm), and 0.1 ± 0.3 mm (range, −0.7 to 0.6 mm) for the superior-inferior (S-I), left-right (L-R), and anterior-posterior (A-P) axes, respectively. The mean shift differences in volumetric registrations were 0.6 ± 0.4 mm (range, −0.2 to 1.6 mm), 0.2 ± 0.4 mm (range, −0.3 to 1.2 mm), and 0.2 ± 0

The influence factors in image quality of multi-slice spiral CT coronary angiography (MSCTA)

International Nuclear Information System (INIS)

Zeng Huiliang; Zhu Xinjin; Liang Jianhao; Zhong Yingze; Chen Xueguang; Ou Weiqian; Wen Haomao; Li Peiwen

2007-01-01

Objective: To evaluate the influence of heart rate on image quality of multi-slice spiral CT coronary angiography(MSCTA) and the optimization of image reconstruction windows. Methods: Retrospectively ECG-gated MSCT coronary angiography were performed in 67 cases. The cases were divided into four groups by heart rate, groupl with heart rate less than 60 beats per minute(bpm), group 2 with heart rate 61-70 bpm, group 3 with heart rate 71-80 bpm and group 4 with heart rate over 81 bpm. The impact of heart rate on image quality of MSCTA and the optimization of image reconstruction windows were evaluated. Results: 4 coronary (RCA,LM,LAD,LCX) segments were analyzed in each patients with regard to image quality. 86.7%(112/128) of the coronary segments were sufficient for analysis in patients with heart rate less than 60 bpm,62.5%(55/88) with 61-70 bpm,40%(8/20) with 71-80 bpm and 12.5%(2/16) with heart rate over 81 bpm, respectively. There were statistically significances between every coronary segments of group 1 and 2, group 3 and 4 (P<0.05). All coronary segments of group 1 were optimally visualized on the image reconstructed at 75% image reconstruction window of' cardiac cycle; 89.5% cases at 75% in group 2; for group 3.55% of coronary artery were best presented at 75% image reconstruction window, 45% of coronary artery at 45%; All coronary segments of group 4 were optimally visualized on the image reconstructed at 45% image reconstruction window. Conclusion: Image quality of MSCT coronary angiography is highly dependent on heart rate. Coronary artery is usually best shown at 75% image reconstruction window of cardiac cycle for those with heart rate less than 70 bpm. 30%-90% image reconstruction should be performed when heart rate is over 71 bpm. (authors)

Spectroscopic (multi-energy) CT distinguishes iodine and barium contrast material in MICE.

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Anderson, N G; Butler, A P; Scott, N J A; Cook, N J; Butzer, J S; Schleich, N; Firsching, M; Grasset, R; de Ruiter, N; Campbell, M; Butler, P H

2010-09-01

Spectral CT differs from dual-energy CT by using a conventional X-ray tube and a photon-counting detector. We wished to produce 3D spectroscopic images of mice that distinguished calcium, iodine and barium. We developed a desktop spectral CT, dubbed MARS, based around the Medipix2 photon-counting energy-discriminating detector. The single conventional X-ray tube operated at constant voltage (75 kVp) and constant current (150 microA). We anaesthetised with ketamine six black mice (C57BL/6). We introduced iodinated contrast material and barium sulphate into the vascular system, alimentary tract and respiratory tract as we euthanised them. The mice were preserved in resin and imaged at four detector energy levels from 12 keV to 42 keV to include the K-edges of iodine (33.0 keV) and barium (37.4 keV). Principal component analysis was applied to reconstructed images to identify components with independent energy response, then displayed in 2D and 3D. Iodinated and barium contrast material was spectrally distinct from soft tissue and bone in all six mice. Calcium, iodine and barium were displayed as separate channels on 3D colour images at contrast agents with K-edges only 4 keV apart. Multi-contrast imaging and molecular CT are potential future applications.

Assessment of sphenoid sinus volume in order to determine sexual identity, using multi-slice CT images

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Habibeh Farazdaghi

2017-02-01

Full Text Available Background and Aims: Gender determination is an important step in identification. For gender determination, anthropometric evaluation is one of the main forensic evaluations. The aim of this study was the assessment of sphenoid sinus volume in order to determine sexual identity, using multi-slice CT images. Materials and Methods: For volumetric analysis, axial paranasal sinus CT scan with 3-mm slice thickness was used. For this study, 80 images (40 women and 40 men older than 18 years were selected. For the assessment of sphenoid sinus volume, Digimizer software was used. The volume of sphenoid sinus was calculated using the following equation: v=∑ (area of each slice × thickness of each slice. Statistical analysis was performed by independent T-test. Results: The mean volume of sphenoid sinus was significantly greater in male gender (P=0.01.The assessed Cut off point was 9/35 cm3, showing that 63.4% of volume assessments greater than cut off point was supposed to be male and 64.1% of volumetry lesser than cut off point were female. Conclusion: According to the area under Roc curve (1.65%, sphenoid sinus volume is not an appropriate factor for differentiation of male and female from each other, which means the predictability of cut off point (9/35 cm3 is 65/1% close to reality.

Multi Detector Computed Tomography Fistulography In Patients of Fistula-in-Ano: An Imaging Collage.

Science.gov (United States)

Bhatt, Shuchi; Jain, Bhupendra Kumar; Singh, Vikas Kumar

2017-01-01

Fistula-in-ano, or perianal fistula, is a challenging clinical condition for both diagnosis and treatment. Imaging modalities such as fistulography, anal endosonography, perineal sonography, magnetic resonance imaging (MRI), and computed tomography (CT) are available for its evaluation. MRI is considered as the modality of choice for an accurate delineation of the tract in relation to the sphincter complex and for the detection of associated complications. However, its availability and affordability is always an issue. Moreover, the requirement to obtain multiple sequences to depict the fistula in detail is cumbersome and confusing for the clinicians to interpret. The inability to show the fistula in relation to normal anatomical structures in a single image is also a limitation. Multi detector computed tomography fistulography ( MDCTF ) is an underutilized technique for defining perianal fistulas. Acquisition of iso-volumetric data sets with instillation of contrast into the fistula delineates the tract and its components. Post-processing with thin sections allows for a generation of good quality images for presentation in various planes (multi-planar reconstructions) and formats (volume rendered technique, maximum intensity projection). MDCTF demonstrates the type of fistula, its extent, whether it is simple or complex, and shows the site of internal opening and associated complications; all in easy to understand images that can be used by the surgeons. Its capability to represent the entire pathology in relation to normal anatomical structures in few images is a definite advantage. MDCTF can be utilized when MRI is contraindicated or not feasible. This pictorial review shares our initial experience with MDCT fistulography in evaluating fistula-in-ano, demonstrates various components of fistulas, and discusses the types of fistulas according to the standard Parks classification.

Peripheral pulmonary arteries: identification at multi-slice spiral CT with 3D reconstruction

International Nuclear Information System (INIS)

Coche, Emmanuel; Pawlak, Sebastien; Dechambre, Stephane; Maldague, Baudouin

2003-01-01

Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries. (orig.)

Inner images of the human body with a 3D CT scanner

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Kobayashi, Hisashi

1994-01-01

This article deals with not only CT-endoscopy (CTES) technique but also various imaging and processing techniques of 3D CT. CTES images, which were obtained from 137 patients with suspected cardiovascular disorder or disease of other tubular organs, were reconstructed using a newly developed volumetric scanner with a slip-ring system. Among the 137 patients, 107 (78%) were successfully diagnosed by CTES. For cardiovascular region, dissecting aneurysm was detected in 27/32, aortitis in 9/9, and intra-arterial thrombosis in 5/6. Various imaging and processing techniques, including CT number conversion technique, multi-threshold range imaging, 'open-window' and 'virtual operation', and long segmental arteriogram by intravenous contrast injection, are displayed in futures. In conclusion, CTES might become a safe and minimally invasive means for observing the inner surface of the tubular organs, particularly of the aorta, without the need of fiberscopic manipulation. (N.K.)

Reproducibility of Lobar Perfusion and Ventilation Quantification Using SPECT/CT Segmentation Software in Lung Cancer Patients.

Science.gov (United States)

Provost, Karine; Leblond, Antoine; Gauthier-Lemire, Annie; Filion, Édith; Bahig, Houda; Lord, Martin

2017-09-01

Planar perfusion scintigraphy with 99m Tc-labeled macroaggregated albumin is often used for pretherapy quantification of regional lung perfusion in lung cancer patients, particularly those with poor respiratory function. However, subdividing lung parenchyma into rectangular regions of interest, as done on planar images, is a poor reflection of true lobar anatomy. New tridimensional methods using SPECT and SPECT/CT have been introduced, including semiautomatic lung segmentation software. The present study evaluated inter- and intraobserver agreement on quantification using SPECT/CT software and compared the results for regional lung contribution obtained with SPECT/CT and planar scintigraphy. Methods: Thirty lung cancer patients underwent ventilation-perfusion scintigraphy with 99m Tc-macroaggregated albumin and 99m Tc-Technegas. The regional lung contribution to perfusion and ventilation was measured on both planar scintigraphy and SPECT/CT using semiautomatic lung segmentation software by 2 observers. Interobserver and intraobserver agreement for the SPECT/CT software was assessed using the intraclass correlation coefficient, Bland-Altman plots, and absolute differences in measurements. Measurements from planar and tridimensional methods were compared using the paired-sample t test and mean absolute differences. Results: Intraclass correlation coefficients were in the excellent range (above 0.9) for both interobserver and intraobserver agreement using the SPECT/CT software. Bland-Altman analyses showed very narrow limits of agreement. Absolute differences were below 2.0% in 96% of both interobserver and intraobserver measurements. There was a statistically significant difference between planar and SPECT/CT methods ( P software is highly reproducible. This tridimensional method yields statistically significant differences in measurements for right lung lobes when compared with planar scintigraphy. We recommend that SPECT/CT-based quantification be used for all lung

4 T MRI of chondrocalcinosis in combination with three-dimensional CT, radiography, and arthroscopy: a report of three cases

International Nuclear Information System (INIS)

Suan, J.C.; Chhem, R.K.; Gati, J.S.; Norley, C.J.; Holdsworth, D.W.

2005-01-01

To describe 4 T MRI techniques in imaging chondrocalcinosis within the knee and examine the results together with those demonstrated using three-dimensional (3D) computed tomography, conventional radiography, and arthroscopy. From a larger clinical imaging study of early osteoarthritis, knee arthroscopy patients were imaged using high-field MRI and high-resolution 3D CT prior to their surgery. Retrospective review of the imaging data diagnosed three patients with chondrocalcinosis. Fat-suppressed 3D spoiled gradient (3D SPGR) and two-dimensional fat-suppressed fast spin echo (FSE) imaging was performed at 4 T. The MR images, multi-planar reformatted CT (MPR-CT) and maximum intensity projection CT (MIP-CT) images, and radiographs were examined by a musculoskeletal radiologist for the presence and location of chondrocalcinosis. The findings from arthroscopy were also included. MRI showed 16 sites of punctate hypointense regions from 18 articular surfaces and five of six menisci with similar signal characteristics. Both meniscal chondrocalcinosis and meniscal tears were clearly visible using the 3D SPGR sequence. Only three sites were demonstrated to have calcification using MPR-CT and MIP-CT revealed an additional three. In articular cartilage surfaces showing surface disruption, arthroscopy demonstrated 11 sites with crystal deposition. Arthroscopy also revealed five menisci with calcification present. Our preliminary findings suggest that imaging chondrocalcinosis using spoiled gradient 4 T MRI is superior and complementary to the other imaging modalities in the detection of crystal deposition in both articular cartilage and menisci. (orig.)

4 T MRI of chondrocalcinosis in combination with three-dimensional CT, radiography, and arthroscopy: a report of three cases

Energy Technology Data Exchange (ETDEWEB)

Suan, J.C.; Chhem, R.K.; Gati, J.S.; Norley, C.J.; Holdsworth, D.W. [Robarts Research Institute, Imaging Research Laboratories, London, Ontario (Canada)

2005-11-01

To describe 4 T MRI techniques in imaging chondrocalcinosis within the knee and examine the results together with those demonstrated using three-dimensional (3D) computed tomography, conventional radiography, and arthroscopy. From a larger clinical imaging study of early osteoarthritis, knee arthroscopy patients were imaged using high-field MRI and high-resolution 3D CT prior to their surgery. Retrospective review of the imaging data diagnosed three patients with chondrocalcinosis. Fat-suppressed 3D spoiled gradient (3D SPGR) and two-dimensional fat-suppressed fast spin echo (FSE) imaging was performed at 4 T. The MR images, multi-planar reformatted CT (MPR-CT) and maximum intensity projection CT (MIP-CT) images, and radiographs were examined by a musculoskeletal radiologist for the presence and location of chondrocalcinosis. The findings from arthroscopy were also included. MRI showed 16 sites of punctate hypointense regions from 18 articular surfaces and five of six menisci with similar signal characteristics. Both meniscal chondrocalcinosis and meniscal tears were clearly visible using the 3D SPGR sequence. Only three sites were demonstrated to have calcification using MPR-CT and MIP-CT revealed an additional three. In articular cartilage surfaces showing surface disruption, arthroscopy demonstrated 11 sites with crystal deposition. Arthroscopy also revealed five menisci with calcification present. Our preliminary findings suggest that imaging chondrocalcinosis using spoiled gradient 4 T MRI is superior and complementary to the other imaging modalities in the detection of crystal deposition in both articular cartilage and menisci. (orig.)

Relationship of radiation dose and spiral pitch for multi-slice CT system

International Nuclear Information System (INIS)

Song Shaojuan; Wang Wei; Liu Chuanya

2006-01-01

Objective: To study the relations of radiation dose and spiral pitch for multi-slice CT system. Methods: 16 mm dose phantom with solidose 300/400 pen-style ion chamber inserted into each of five holes in turn was scanned with different spiral pitch by LightSpeed 16-slice CT and Sensation 16-slice and 64-slice CT and radiation dose. Results: CTDI vol of axial scan and spiral scan for the three types of CT system are: (1) LightSpeed 16-slice CT: 28.9 (axial), 51.4 (pitch 0.562), 30.8 (pitch 0.938) and 16.5 ( pitch 1.75 ); (2) Sensation 16-slice CT: 41.2(axial) and 40.3(pitch 0.5) ,41.5(pitch 1) and 43.2(pitch 1.5); (3) Sensation 64- slice CT: 41.2(axial) and 40.3(pitch 0.5),41.5(pitch 1),43.2(pitch 1.5). Conclusions: For LightSpeed 16-slice CT, the measured radiation dose decreased with the increase of spiral pitch, the image quality could keep constant only if we increase mAs. While for Sensation 16-slice and 64-slice CT system, the measured radiation dose was identical for different pitch, and the image quality was identical because of the use of mAs auto control technique The mAs should be adjusted in different way according to the type of CT system when the pitch is changed in daily operation. (authors)

Clinical impact of SPECT-CT in the diagnosis and surgical management of hyper-parathyroidism.

Science.gov (United States)

Tokmak, Handan; Demirkol, Mehmet Onur; Alagöl, Faruk; Tezelman, Serdar; Terzioglu, Tarik

2014-01-01

Hyper-functioning parathyroid glands with autonomous overproduction of PTH is the most frequent cause of hypercalcemia in outpatient populations with primary hyper-parathyroidism. It is generally caused by a solitary adenoma in 80%-90% of patients. Despite the various methodologies that are available for preoperative localization of parathyroid lesions, there is still no certain preoperative imaging algorithm to guide a surgical approach prior to the management of primary hyper-parathyroidism (P-HPT). Minimally invasive surgery has replaced the traditional bilateral neck exploration (BNE) as the initial approach in parathyroidectomy at many referral hospitals worldwide. In our study, we investigated diagnostic contributions of SPECT-CT combined with conventional planar scintigraphy in the detection of hyper-functioning parathyroid gland localization, since planar imaging has limitations. We also evaluated the efficacy of preoperative USG in adding to initial diagnostic imaging algorithms to localize a parathyroid adenoma. A total of 256 consecutive surgically naive patients with hyper-parathyroidism diagnosis were included in the following preoperative localization study. The study consisted of 256 consecutive patients with HPT, with a selected 154 patients who had neck surgery with definitive histology reports. All patients had 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) double-phase scintigraphy. The SPECT-CT procedure, combined with standard 99mTc-MIBI planar parathyroid scintigraphy with a pinhole and parallel-hole collimator to evaluate whether the SPECT-CT procedure was able to provide additional information in the localization of the pathology, caused hyper-parathyroidism in both P-HPT and S-HPT. In the 154 P-HPT patients, 168 lesions (142 adenomas including 2 intrathyroidal and 2 double adenoma, 2 carcinoma, and 22 hyperplastic glands (four patients had MEN I, each with four hyperplastic glands)), were found at surgery. SPECT-CT detected more lesions than

Detection of the anatomic structure and pathology in animal lung specimens: comparison of micro CT and multi-detector row CT

International Nuclear Information System (INIS)

Lim, Kun Young; Lee, Hyun Ju; Lee, Chang Hyun; Son, Kyu Ri; Goo, Jin Mo; Im, Jung Gi; Seo, Joon Beom

2006-01-01

We wanted to compare the capability of micro CT and the clinically available thin-slice multi-detector row CT (MDCT) for demonstrating fine anatomic structures and pathological lesions in formalin-fixed lung specimens. The porcine lung with shark liver oil-induced lipoid pneumonia and the canine lung with pulmonary paragonimiasis were fixed by ventilating them with formalin vapor, and they were then sliced into one-centimeter thick sections. Micro CT (section thickness, 18 micrometer) and MDCT (section thickness, 0.75 mm) images were acquired in four of the lung slices of the lipoid pneumonia specimen and in five of the lung slices of the paragonimiasis specimen. On 62 pairs of micro CT and MDCT images, 169 pairs of rectangular ROIs were manually drawn in the corresponding locations. Two chest radiologists recorded the detectability of three kinds of anatomic structures (lobular core structure, interlobular septum and small bronchiolar lumen) and two kinds of pathological lesions (ground-glass opacity and consolidation) with using a five-point scale. The statistical comparison was performed by using the Wilcoxon signed rank test. Interobserver agreement was evaluated with kappa statistics. For all observers, all the kinds of anatomic structures and pathological lesions were detected better on the micro CT images than on the MDCT images (ρ < 0.01). Agreement was fair between two observers (κ = 0.38, ρ < 0.001). The fine anatomic structures and pathological lesions of the lung were more accurately demonstrated on micro CT than on thin-slice MDCT in the inflated and fixed lung specimens

Detection of the anatomic structure and pathology in animal lung specimens: comparison of micro CT and multi-detector row CT

Energy Technology Data Exchange (ETDEWEB)

Lim, Kun Young [National Cancer Center, Goyang (Korea, Republic of); Lee, Hyun Ju; Lee, Chang Hyun; Son, Kyu Ri; Goo, Jin Mo; Im, Jung Gi [Seoul National University Hospital and the Institute of Radiation Medicine, Seoul (Korea, Republic of); Seo, Joon Beom [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

2006-05-15

We wanted to compare the capability of micro CT and the clinically available thin-slice multi-detector row CT (MDCT) for demonstrating fine anatomic structures and pathological lesions in formalin-fixed lung specimens. The porcine lung with shark liver oil-induced lipoid pneumonia and the canine lung with pulmonary paragonimiasis were fixed by ventilating them with formalin vapor, and they were then sliced into one-centimeter thick sections. Micro CT (section thickness, 18 micrometer) and MDCT (section thickness, 0.75 mm) images were acquired in four of the lung slices of the lipoid pneumonia specimen and in five of the lung slices of the paragonimiasis specimen. On 62 pairs of micro CT and MDCT images, 169 pairs of rectangular ROIs were manually drawn in the corresponding locations. Two chest radiologists recorded the detectability of three kinds of anatomic structures (lobular core structure, interlobular septum and small bronchiolar lumen) and two kinds of pathological lesions (ground-glass opacity and consolidation) with using a five-point scale. The statistical comparison was performed by using the Wilcoxon signed rank test. Interobserver agreement was evaluated with kappa statistics. For all observers, all the kinds of anatomic structures and pathological lesions were detected better on the micro CT images than on the MDCT images ({rho} < 0.01). Agreement was fair between two observers ({kappa} = 0.38, {rho} < 0.001). The fine anatomic structures and pathological lesions of the lung were more accurately demonstrated on micro CT than on thin-slice MDCT in the inflated and fixed lung specimens.

4D-CT Lung registration using anatomy-based multi-level multi-resolution optical flow analysis and thin-plate splines.

Science.gov (United States)

Min, Yugang; Neylon, John; Shah, Amish; Meeks, Sanford; Lee, Percy; Kupelian, Patrick; Santhanam, Anand P

2014-09-01

The accuracy of 4D-CT registration is limited by inconsistent Hounsfield unit (HU) values in the 4D-CT data from one respiratory phase to another and lower image contrast for lung substructures. This paper presents an optical flow and thin-plate spline (TPS)-based 4D-CT registration method to account for these limitations. The use of unified HU values on multiple anatomy levels (e.g., the lung contour, blood vessels, and parenchyma) accounts for registration errors by inconsistent landmark HU value. While 3D multi-resolution optical flow analysis registers each anatomical level, TPS is employed for propagating the results from one anatomical level to another ultimately leading to the 4D-CT registration. 4D-CT registration was validated using target registration error (TRE), inverse consistency error (ICE) metrics, and a statistical image comparison using Gamma criteria of 1 % intensity difference in 2 mm(3) window range. Validation results showed that the proposed method was able to register CT lung datasets with TRE and ICE values <3 mm. In addition, the average number of voxel that failed the Gamma criteria was <3 %, which supports the clinical applicability of the propose registration mechanism. The proposed 4D-CT registration computes the volumetric lung deformations within clinically viable accuracy.

CT and MR imaging of craniopharyngioma

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Tsuda, M. [Tohoku Univ. School of Medicine, Sendai (Japan). Dept. of Radiology; Takahashi, S. [Tohoku Univ. School of Medicine, Sendai (Japan). Dept. of Radiology; Higano, S. [Tohoku Univ. School of Medicine, Sendai (Japan). Dept. of Radiology; Kurihara, N. [Tohoku Univ. School of Medicine, Sendai (Japan). Dept. of Radiology; Ikeda, H. [Tohoku Univ. School of Medicine, Sendai (Japan). Dept. of Neurosurgery; Sakamoto, K. [Tohoku Univ. School of Medicine, Sendai (Japan). Dept. of Radiology

1997-05-01

We reviewed imaging findings of CT and MR imaging in 20 cases of surgically confirmed craniopharyngioma in an attempt to determine their relation to patterns of tumor extent. The relationship between these patterns and the frequency of preoperative CT diagnosis and MR imaging diagnosis according to the surgical diagnosis were determined. The CT technique was superior to MR imaging in the detection of calcification. The MR imaging technique was superior to CT for determining tumor extent and provided valuable information about the relationships of the tumor to surrounding structures. Thus, CT and MR imaging have complementary roles in the diagnosis of craniopharyngiomas. In cases of possible craniopharyngioma, noncontrast sagittal T1-weighted images may enable the identification of the normal pituitary, possibly leading to the correct diagnosis. (orig.)

CT and MR imaging of craniopharyngioma

International Nuclear Information System (INIS)

Tsuda, M.; Takahashi, S.; Higano, S.; Kurihara, N.; Ikeda, H.; Sakamoto, K.

1997-01-01

We reviewed imaging findings of CT and MR imaging in 20 cases of surgically confirmed craniopharyngioma in an attempt to determine their relation to patterns of tumor extent. The relationship between these patterns and the frequency of preoperative CT diagnosis and MR imaging diagnosis according to the surgical diagnosis were determined. The CT technique was superior to MR imaging in the detection of calcification. The MR imaging technique was superior to CT for determining tumor extent and provided valuable information about the relationships of the tumor to surrounding structures. Thus, CT and MR imaging have complementary roles in the diagnosis of craniopharyngiomas. In cases of possible craniopharyngioma, noncontrast sagittal T1-weighted images may enable the identification of the normal pituitary, possibly leading to the correct diagnosis. (orig.)

A comparative study of FDG PET/CT and enhanced multi-detector CT for detecting liver metastasis according to the size and location.

Science.gov (United States)

Park, Jung Mi; Kim, Il Young; Kim, Sang Won; Lee, Sang Mi; Kim, Hyun Gi; Kim, Shin Young; Shin, Hyung Chul

2013-04-01

The aim of this study was to compare the diagnosability between (18)F-fluorodeoxyglucose (FDG) PET/CT and enhanced multi-detector CT (MDCT) for the detection of liver metastasis (LM) according to the size and location in liver and to evaluate standard maximum standardized uptake values (SUVmax) of all liver metastatic lesions. One hundred two consecutive patients with malignancy who underwent both FDG PET/CT and MDCT for LM evaluation were retrospectively reviewed. Among them, 56 patients with LM were enrolled in this study. LM was confirmed by follow-up imaging studies after at least 6 months or by histopathology. FDG PET/CT and MDCT images were visually analyzed using three-point scale by the consensus of two radiologists and two nuclear medicine physicians. The size and location (central vs. sub-capsular) of the all liver lesions were evaluated using MDCT images. Furthermore, SUVmax of all liver lesions on FDG PET/CT images were calculated. A total of 146 liver lesions were detected by FDG PET/CT and MDCT and 142 of the lesions were diagnosed as LM. The detection rates of MDCT and FDG PET/CT for LM by visual analysis were 77 and 78%, respectively. There was no significant difference of detection rate according to the overall location and size of the lesions. However, FDG PET/CT was more sensitive than MDCT for detecting small and sub-capsular LM. The detection rate of FDG PET/CT for LM was 68% by the cutoff SUVmax of 2.7. Although the diagnosabilities of MDCT and FDG PET/CT for detecting LM were comparable, FDG PET/CT is superior to MDCT for detecting small LM located in the sub-capsular portion of liver.

Comparison of single photon emission computed tomography-computed tomography, computed tomography, single photon emission computed tomography and planar scintigraphy for characterization of isolated skull lesions seen on bone scintigraphy in cancer patients

International Nuclear Information System (INIS)

Sharma, Punit; Jain, Tarun Kumar; Reddy, Rama Mohan; Faizi, Nauroze Ashgar; Bal, Chandrasekhar; Malhotra, Arun; Kumar, Rakesh

2014-01-01

The purpose of this study is to evaluate the added value of single photon emission computed tomography-computed tomography (SPECT-CT) over planar scintigraphy, SPECT and CT alone for characterization of isolated skull lesions in bone scintigraphy (BS) in cancer patients. A total of 32 cancer patients (age: 39.5 ± 21.9; male: female - 1:1) with 36 isolated skull lesions on planar BS, underwent SPECT-CT of skull. Planar BS, SPECT, CT and SPECT-CT images were evaluated in separate sessions to minimize recall bias. A scoring scale of 1-5 was used, where 1 is definitely metastatic, 2 is probably metastatic, 3 is indeterminate, 4 is probably benign and 5 is definitely benign. With receiver operating characteristic analysis area under the curves (AUC) was calculated for each modality. For calculation of sensitivity, specificity and predictive values a Score ≤3 was taken as metastatic. Clinical/imaging follow-up and/or histopathology were taken as reference standard. Of 36 skull lesions 11 lesions each were on frontal, parietal and occipital bone while three lesions were in the temporal bone. Of these 36 lesions, 16 were indeterminate (Score-3) on planar and SPECT, five on CT and none on SPECT-CT. The AUC was largest for SPECT-CT followed by CT, SPECT and planar scintigraphy, respectively. Planar scintigraphy was inferior to SPECT-CT (P = 0.006) and CT (P = 0.012) but not SPECT (P = 0.975). SPECT was also inferior to SPECT-CT (P = 0.007) and CT (P = 0.015). Although no significant difference was found between SPECT-CT and CT (P = 0.469), the former was more specific (100% vs. 94%). SPECT-CT is better than planar scintigraphy and SPECT alone for correctly characterizing isolated skull lesions on BS in cancer patients. It is more specific than CT, but provides no significant advantage over CT alone for this purpose

The impact of different imaging modalities of 67Ga scintigraphy on the image quality and the ability in detection of lesions

International Nuclear Information System (INIS)

Liu Xiuqin; Li Wenchan; Zhang Jianfei; Yao Zhiming

2009-01-01

Objective: 67 Ga scintigraphy is an important method in detection of active sarcoidosis. The aim of this research was to study the influence of planar and tomography. with and without CT attenuation correction (AC and NAC), on 67 Ga images on the image quality and the ability in detection of lesions. Methods: Thirty one patients (13 male, 18 female, age range: 33-87 years)with sarcoidosis underwent 67 Ga planar and tomographic scans. AC and NAC.The imaging quality and the ability in detection of hyper-radioactive lymph nodes in lung hilar and mediastinal(1esion) among the planar, AC and NAC images were compared. The paired t-test and χ 2 -test were used for data analysis with SPSS 10.0 software. Results: From planar, NAC to AC, the image quality was better and better in proper order (χ 2 = 25.88, P 67 Ga tomographic scintigraphy can impmve the ability in detection of hyperradioactive lung hilar and mediastinal lymph nodes compared with planar image does. CT AC for 67 Ga tomography can improve the tomographic imaging quality. (authors)

CT images of gossypiboma

International Nuclear Information System (INIS)

Jeon, Hae Jeong; Lim, Jong Nam; Choi, Young Chil; Park, Jeong Hee

1994-01-01

Surgical sponges retained after laparotomy can cause serious problem if they were not be identified in early state. In these circumstances abdominal CT yields the accurate diagnostic images. The purpose of this report is to present highly indicative findings permitting correct preoperative diagnosis of the gossypiboma. We experienced three cases in which CT showed the images sufficiently characteristic to suggest the correct preoperative diagnosis. We evaluated retrospectively the radiological images of gossypiboma confirmed by operation. Three patients were admitted due to palpable masses. Two female patients had medical histories of cesarean sections and a male patient had been operated due to malignant fibrous histiocytoma, previously. Abdominal CT scan of one case revealed huge ovoid hypodense mass with enhanced peripheral rim. Calcific spots and whirl-like stripes were noted within the lesion. Towel was found in pathologic specimen. CT images of two patients showed well-encapsulated, mixed fluid and soft tissue density mass with several gas bubbles. Surgical sponges were found within abscesses. The authors conclude that these characteristic CT findings and careful histories of surgery are very useful for correct pre-operative diagnosis and permit the guideline for the optimal plan of the surgical treatment

CT images of gossypiboma

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Jeon, Hae Jeong; Lim, Jong Nam; Choi, Young Chil; Park, Jeong Hee [College of Medicine, Kon-Kuk University, Seoul (Korea, Republic of)

1994-04-15

Surgical sponges retained after laparotomy can cause serious problem if they were not be identified in early state. In these circumstances abdominal CT yields the accurate diagnostic images. The purpose of this report is to present highly indicative findings permitting correct preoperative diagnosis of the gossypiboma. We experienced three cases in which CT showed the images sufficiently characteristic to suggest the correct preoperative diagnosis. We evaluated retrospectively the radiological images of gossypiboma confirmed by operation. Three patients were admitted due to palpable masses. Two female patients had medical histories of cesarean sections and a male patient had been operated due to malignant fibrous histiocytoma, previously. Abdominal CT scan of one case revealed huge ovoid hypodense mass with enhanced peripheral rim. Calcific spots and whirl-like stripes were noted within the lesion. Towel was found in pathologic specimen. CT images of two patients showed well-encapsulated, mixed fluid and soft tissue density mass with several gas bubbles. Surgical sponges were found within abscesses. The authors conclude that these characteristic CT findings and careful histories of surgery are very useful for correct pre-operative diagnosis and permit the guideline for the optimal plan of the surgical treatment.

SU-E-I-93: Improved Imaging Quality for Multislice Helical CT Via Sparsity Regularized Iterative Image Reconstruction Method Based On Tensor Framelet

International Nuclear Information System (INIS)

Nam, H; Guo, M; Lee, K; Li, R; Xing, L; Gao, H

2014-01-01

Purpose: Inspired by compressive sensing, sparsity regularized iterative reconstruction method has been extensively studied. However, its utility pertinent to multislice helical 4D CT for radiotherapy with respect to imaging quality, dose, and time has not been thoroughly addressed. As the beginning of such an investigation, this work carries out the initial comparison of reconstructed imaging quality between sparsity regularized iterative method and analytic method through static phantom studies using a state-of-art 128-channel multi-slice Siemens helical CT scanner. Methods: In our iterative method, tensor framelet (TF) is chosen as the regularization method for its superior performance from total variation regularization in terms of reduced piecewise-constant artifacts and improved imaging quality that has been demonstrated in our prior work. On the other hand, X-ray transforms and its adjoints are computed on-the-fly through GPU implementation using our previous developed fast parallel algorithms with O(1) complexity per computing thread. For comparison, both FDK (approximate analytic method) and Katsevich algorithm (exact analytic method) are used for multislice helical CT image reconstruction. Results: The phantom experimental data with different imaging doses were acquired using a state-of-art 128-channel multi-slice Siemens helical CT scanner. The reconstructed image quality was compared between TF-based iterative method, FDK and Katsevich algorithm with the quantitative analysis for characterizing signal-to-noise ratio, image contrast, and spatial resolution of high-contrast and low-contrast objects. Conclusion: The experimental results suggest that our tensor framelet regularized iterative reconstruction algorithm improves the helical CT imaging quality from FDK and Katsevich algorithm for static experimental phantom studies that have been performed

Multi-organ segmentation from multi-phase abdominal CT via 4D graphs using enhancement, shape and location optimization.

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Linguraru, Marius George; Pura, John A; Chowdhury, Ananda S; Summers, Ronald M

2010-01-01

The interpretation of medical images benefits from anatomical and physiological priors to optimize computer-aided diagnosis (CAD) applications. Diagnosis also relies on the comprehensive analysis of multiple organs and quantitative measures of soft tissue. An automated method optimized for medical image data is presented for the simultaneous segmentation of four abdominal organs from 4D CT data using graph cuts. Contrast-enhanced CT scans were obtained at two phases: non-contrast and portal venous. Intra-patient data were spatially normalized by non-linear registration. Then 4D erosion using population historic information of contrast-enhanced liver, spleen, and kidneys was applied to multi-phase data to initialize the 4D graph and adapt to patient specific data. CT enhancement information and constraints on shape, from Parzen windows, and location, from a probabilistic atlas, were input into a new formulation of a 4D graph. Comparative results demonstrate the effects of appearance and enhancement, and shape and location on organ segmentation.

Additional value of hybrid SPECT/CT systems in neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas.

Science.gov (United States)

Wong, K K; Chondrogiannis, S; Fuster, D; Ruiz, C; Marzola, M C; Giammarile, F; Colletti, P M; Rubello, D

The aim of this review was to evaluate the potential advantages of SPECT/CT hybrid imaging in the management of neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas. From the collected data, the superiority of fused images was observed as providing both functional/molecular and morphological imaging compared to planar imaging. This provided an improvement in diagnostic imaging, with significant advantages as regards: (1) precise locating of the lesions; (2) an improvement in characterization of the findings, resulting higher specificity, improved sensitivity, and overall greater accuracy, (3) additional anatomical information derived from the CT component; (4) CT-based attenuation correction and potential for volumetric dosimetry calculations, and (5) improvement on the impact on patient management (e.g. in better defining treatment plans, in shortening surgical operating times). It can be concluded that SPECT/CT hybrid imaging provides the nuclear medicine physician with a powerful imaging modality in comparison to planar imaging, providing essential information about the location of lesions, and high quality homogeneous images. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Computer aided detection system for Osteoporosis using low dose thoracic 3D CT images

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Tsuji, Daisuke; Matsuhiro, Mikio; Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Harada, Masafumi; Kusumoto, Masahiko; Tsuchida, Takaaki; Eguchi, Kenji; Kaneko, Masahiro

2018-02-01

The patient of osteoporosis is about 13 million people in Japan and it is one of healthy life problems in the aging society. It is necessary to do early stage detection and treatment in order to prevent the osteoporosis. Multi-slice CT technology has been improving the three dimensional (3D) image analysis with higher resolution and shorter scan time. The 3D image analysis of thoracic vertebra can be used for supporting to diagnosis of osteoporosis. This analysis can be used for lung cancer detection at the same time. We develop method of shape analysis and CT values of spongy bone for the detection osteoporosis. Osteoporosis and lung cancer screening show high extraction rate by the thoracic vertebral evaluation CT images. In addition, we created standard pattern of CT value per thoracic vertebra for male age group using 298 low dose data.

A temporal subtraction method for thoracic CT images based on generalized gradient vector flow

International Nuclear Information System (INIS)

Miyake, Noriaki; Kim, H.; Maeda, Shinya; Itai, Yoshinori; Tan, J.K.; Ishikawa, Seiji; Katsuragawa, Shigehiko

2010-01-01

A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes (such as formation of new lesions and changes in existing abnormalities) on medical images by removing most of the normal structures. If image registration is incorrect, not only the interval changes but also the normal structures would be appeared as some artifacts on the temporal subtraction image. In a temporal subtraction technique for 2-D X-ray image, the effectiveness is shown through a lot of clinical evaluation experiments, and practical use is advancing. Moreover, the MDCT (Multi-Detector row Computed Tomography) can easily introduced on medical field, the development of a temporal subtraction for thoracic CT Images is expected. In our study, a temporal subtraction technique for thoracic CT Images is developed. As the technique, the vector fields are described by use of GGVF (Generalized Gradient Vector Flow) from the previous and current CT images. Afterwards, VOI (Volume of Interest) are set up on the previous and current CT image pairs. The shift vectors are calculated by using nearest neighbor matching of the vector fields in these VOIs. The search kernel on previous CT image is set up from the obtained shift vector. The previous CT voxel which resemble standard the current voxel is detected by voxel value and vector of the GGVF in the kernel. And, the previous CT image is transformed to the same coordinate of standard voxel. Finally, temporal subtraction image is made by subtraction of a warping image from a current one. To verify the proposal method, the result of application to 7 cases and the effectiveness are described. (author)

Generalized multi-dimensional adaptive filtering for conventional and spiral single-slice, multi-slice, and cone-beam CT

International Nuclear Information System (INIS)

Kachelriess, Marc; Watzke, Oliver; Kalender, Willi A.

2001-01-01

In modern computed tomography (CT) there is a strong desire to reduce patient dose and/or to improve image quality by increasing spatial resolution and decreasing image noise. These are conflicting demands since increasing resolution at a constant noise level or decreasing noise at a constant resolution level implies a higher demand on x-ray power and an increase of patient dose. X-ray tube power is limited due to technical reasons. We therefore developed a generalized multi-dimensional adaptive filtering approach that applies nonlinear filters in up to three dimensions in the raw data domain. This new method differs from approaches in the literature since our nonlinear filters are applied not only in the detector row direction but also in the view and in the z-direction. This true three-dimensional filtering improves the quantum statistics of a measured projection value proportional to the third power of the filter size. Resolution tradeoffs are shared among these three dimensions and thus are considerably smaller as compared to one-dimensional smoothing approaches. Patient data of spiral and sequential single- and multi-slice CT scans as well as simulated spiral cone-beam data were processed to evaluate these new approaches. Image quality was assessed by evaluation of difference images, by measuring the image noise and the noise reduction, and by calculating the image resolution using point spread functions. The use of generalized adaptive filters helps to reduce image noise or, alternatively, patient dose. Image noise structures, typically along the direction of the highest attenuation, are effectively reduced. Noise reduction values of typically 30%-60% can be achieved in noncylindrical body regions like the shoulder. The loss in image resolution remains below 5% for all cases. In addition, the new method has a great potential to reduce metal artifacts, e.g., in the hip region

Detection and classification of focal liver lesions in patients with colorectal cancer: Retrospective comparison of diffusion-weighted MR imaging and multi-slice CT

International Nuclear Information System (INIS)

Eiber, Matthias; Fingerle, Alexander A.; Brügel, Melanie; Gaa, Jochen; Rummeny, Ernst J.; Holzapfel, Konstantin

2012-01-01

Objectives: To compare the diagnostic performance of diffusion-weighted MR imaging (DWI) with multi-slice CT (MS-CT) in the detection and classification of focal liver lesions in patients with colorectal cancer. Methods: In a retrospective study 68 patients who underwent DWI at 1.5 T (b-values of 50, 300 and 600 s/mm 2 ) and contrast-enhanced MS-CT were analysed by two radiologists blinded to the clinical results. Imaging results were correlated with intraoperative surgical and ultrasound findings (n = 24), imaging follow-up or PET (n = 44). Sensitivity of DWI and MS-CT in detection of focal liver lesions was compared on a per-lesion and a per-segment basis. Receiver operator-characteristic (ROC) curves to determine the diagnostic performance and the sensitivities of correctly identifying liver metastases on a segmental base were calculated. Results: For lesion detection, DWI was significantly superior to MS-CT both on a per-lesion (difference in sensitivities for reader 1 and 2 22.65% and 19.06%, p < 0.0001) and a per-segment basis (16.86% and 11.76%, p < 0.0001). Especially lesions smaller than 10 mm were better detected with DWI compared to MS-CT (difference 41.10% and 29.45%, p < 0.0001). ROC-analysis showed superiority for lesions classification (p < 0.0001) of DWI (AUC: 0.949 and 0.951) as compared to MS-CT (AUC: 0.879 and 0.892, p < 0.0001 and p = 0.005). DWI was able to filter out metastatic segments with a higher sensitivity (88.2 and 86.5%) compared to MS-CT (68.0 and 67.4%, p < 0.0001 and p = 0.005, respectively). Conclusion: Compared to MS-CT DWI is both more sensitive in the detection of liver lesions and more accurate in determining the extent of metastatic disease in patients with colorectal cancer and therefore might help to optimize therapeutic management in those patients.

Mediastinal and hilar lymphadenopathy: cross-referenced anatomy on axial and coronal images displayed by using multi-detector row CT

International Nuclear Information System (INIS)

Lee, Ju Hyun; Lee, Kyung Soo; Kim, Tae Sung; Yi, Chin A; Cho, Jae Min; Lee, Min Hee

2003-01-01

The accurate evaluation of mediastinal and pulmonary hilar lymphadenopathy, especially in patients with lung cancer, is important for determining treatment options and evaluating the response to therapy. To indicate nodal location in detail, mediastinal and hilar lymph nodes have been assigned to one of 14 nodal stations. Mediastinal nodes of greater than 10 mm short-axis diameter are regarded as abnormal, irrespective of their nodal station, while hilar nodes are considered abnormal if their diameter is greater than 10 mm in any axis or they are convex compared to surrounding lung. By providing multiplanar images, multi-detector row CT allows detailed evaluation of thoracic anatomic structures more easily than in the past, when axial images only were available. At cross-referenced imaging, a lymph node depicted at axial imaging in one anatomical location can be visualized simultaneously and automatically at coronal imaging at the exactly corresponding anatomical location. Cross-referenced coincidental axial and coronal images help assess both the size and morphology of mediastinal and hilar lymph nodes

Pore-scale Simulation and Imaging of Multi-phase Flow and Transport in Porous Media (Invited)

Science.gov (United States)

Crawshaw, J.; Welch, N.; Daher, I.; Yang, J.; Shah, S.; Grey, F.; Boek, E.

2013-12-01

We combine multi-scale imaging and computer simulation of multi-phase flow and reactive transport in rock samples to enhance our fundamental understanding of long term CO2 storage in rock formations. The imaging techniques include Confocal Laser Scanning Microscopy (CLSM), micro-CT and medical CT scanning, with spatial resolutions ranging from sub-micron to mm respectively. First, we report a new sample preparation technique to study micro-porosity in carbonates using CLSM in 3 dimensions. Second, we use micro-CT scanning to generate high resolution 3D pore space images of carbonate and cap rock samples. In addition, we employ micro-CT to image the processes of evaporation in fractures and cap rock degradation due to exposure to CO2 flow. Third, we use medical CT scanning to image spontaneous imbibition in carbonate rock samples. Our imaging studies are complemented by computer simulations of multi-phase flow and transport, using the 3D pore space images obtained from the scanning experiments. We have developed a massively parallel lattice-Boltzmann (LB) code to calculate the single phase flow field in these pore space images. The resulting flow fields are then used to calculate hydrodynamic dispersion using a novel scheme to predict probability distributions for molecular displacements using the LB method and a streamline algorithm, modified for optimal solid boundary conditions. We calculate solute transport on pore-space images of rock cores with increasing degree of heterogeneity: a bead pack, Bentheimer sandstone and Portland carbonate. We observe that for homogeneous rock samples, such as bead packs, the displacement distribution remains Gaussian with time increasing. In the more heterogeneous rocks, on the other hand, the displacement distribution develops a stagnant part. We observe that the fraction of trapped solute increases from the beadpack (0 %) to Bentheimer sandstone (1.5 %) to Portland carbonate (8.1 %), in excellent agreement with PFG

Readout-segmented echo-planar imaging improves the image quality of diffusion-weighted MR imaging in rectal cancer: Comparison with single-shot echo-planar diffusion-weighted sequences

Energy Technology Data Exchange (ETDEWEB)

Xia, Chun-chao; Liu, Xi; Peng, Wan-lin; Li, Lei; Zhang, Jin-ge [Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Meng, Wen-jian; Deng, Xiang-bing [Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Zuo, Pan-li [Siemens Healthcare, MR Collaborations NE Asia, 100010, Beijing (China); Li, Zhen-lin, E-mail: lzlcd01@126.com [Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

2016-10-15

Purpose: To determine whether readout-segmented echo-planar imaging (rs-EPI) diffusion-weighted imaging (DWI) can improve the image quality in patients with rectal cancer compared with single-shot echo-planar imaging (ss-EPI) DWI using 3.0 T magnetic resonance (MR) imaging. Materials and methods: This study was approved by the Institutional Review Board, and informed consent was obtained from all patients. Seventy-one patients with rectal cancer were enrolled in this study. For all patients, both rs-EPI and ss-EPI DWI were performed using a 3T MR scanner. Two radiologists independently assessed the overall image quality, lesion conspicuity, geometric distortion and distinction of anatomical structures. The signal-to-noise ratio (SNR), lesion contrast, contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) were also measured. Comparisons of the quantitative and qualitative parameters between the two sequences were performed using the paired t-test and the Wilcoxon signed rank test. Results: The scores of overall image quality, lesion conspicuity, geometric distortion and distinction of anatomical structures of rs-EPI were all significantly higher than those of ss-EPI (all p < 0.05). The SNR and CNR were higher in rs-EPI than those in ss-EPI (all p < 0.05). There was no significant difference between ss-EPI and rs-EPI with regard to ROI size and mean ADCs of the tumour (p = 0.574 and p = 0.479, respectively), but the mean ADC of the normal tissue was higher in rs-EPI than in ss-EPI (1.73 ± 0.30 × 10{sup −3} mm{sup 2}/s vs. 1.60 ± 0.31 × 10{sup −3} mm{sup 2}/s, p = 0.001). Conclusions: DW imaging based on readout-segmented echo-planar imaging is a clinically useful technique to improve the image quality for the purpose of evaluating lesions in patients with rectal tumours.

High precision localization of intracerebral hemorrhage based on 3D MPR on head CT images

Science.gov (United States)

Sun, Jianyong; Hou, Xiaoshuai; Sun, Shujie; Zhang, Jianguo

2017-03-01

The key step for minimally invasive intracerebral hemorrhage surgery is precisely positioning the hematoma location in the brain before and during the hematoma surgery, which can significantly improves the success rate of puncture hematoma. We designed a 3D computerized surgical plan (CSP) workstation precisely to locate brain hematoma based on Multi-Planar Reconstruction (MPR) visualization technique. We used ten patients' CT/MR studies to verify our designed CSP intracerebral hemorrhage localization method. With the doctor's assessment and comparing with the results of manual measurements, the output of CSP WS for hematoma surgery is more precise and reliable than manual procedure.

Short-scan-time multi-slice diffusion MRI of the mouse cervical spinal cord using echo planar imaging.

Science.gov (United States)

Callot, Virginie; Duhamel, Guillaume; Cozzone, Patrick J; Kober, Frank

2008-10-01

Mouse spinal cord (SC) diffusion-weighted imaging (DWI) provides important information on tissue morphology and structural changes that may occur during pathologies such as multiple sclerosis or SC injury. The acquisition scheme of the commonly used DWI techniques is based on conventional spin-echo encoding, which is time-consuming. The purpose of this work was to investigate whether the use of echo planar imaging (EPI) would provide good-quality diffusion MR images of mouse SC, as well as accurate measurements of diffusion-derived metrics, and thus enable diffusion tensor imaging (DTI) and highly resolved DWI within reasonable scan times. A four-shot diffusion-weighted spin-echo EPI (SE-EPI) sequence was evaluated at 11.75 T on a group of healthy mice (n = 10). SE-EPI-derived apparent diffusion coefficients of gray and white matter were compared with those obtained using a conventional spin-echo sequence (c-SE) to validate the accuracy of the method. To take advantage of the reduction in acquisition time offered by the EPI sequence, multi-slice DTI acquisitions were performed covering the cervical segments (six slices, six diffusion-encoding directions, three b values) within 30 min (vs 2 h for c-SE). From these measurements, fractional anisotropy and mean diffusivities were calculated, and fiber tracking along the C1 to C6 cervical segments was performed. In addition, high-resolution images (74 x 94 microm(2)) were acquired within 5 min per direction. Clear delineation of gray and white matter and identical apparent diffusion coefficient values were obtained, with a threefold reduction in acquisition time compared with c-SE. While overcoming the difficulties associated with high spatially and temporally resolved DTI measurements, the present SE-EPI approach permitted identification of reliable quantitative parameters with a reproducibility compatible with the detection of pathologies. The SE-EPI method may be particularly valuable when multiple sets of images

The prevalence of thyroid tissue along the thyroglossal tract on SPECT/CT following I131 ablation therapy after total thyroidectomy for thyroid cancer

International Nuclear Information System (INIS)

Barber, T.W.; Cherk, M.H.; Yap, K.S.K.; Kalff, V.; Topliss, D.J.; Serpell, J.W.

2015-01-01

Full text of publication follows. Aim: the aims of this study are first to determine the prevalence of thyroid tissue along the thyroglossal tract on SPECT/CT and secondly to assess the contribution of this tissue to total neck I-131 activity in patients treated with I-131 ablation therapy after total thyroidectomy for thyroid cancer. Materials and methods: a total of 63 consecutive patients with well differentiated thyroid cancer treated with total thyroidectomy underwent whole body planar imaging and SPECT/CT of the neck 48 hours following ablative I-131 therapy. On SPECT/CT, thyroglossal tract thyroid tissue was defined as radioiodine activity in the anterior neck, superior to the thyroid bed in close proximity to the midline without evidence of localisation to lymph nodes. On planar imaging, thyroglossal tract thyroid tissue was defined as linear radioiodine activity in the midline of the neck superior to the thyroid bed. SPECT/CT and planar images were classified by two independent reviewers as positive, negative or equivocal with interobserver agreement quantified using a Kappa score. Disagreement was resolved using a third reviewer. Quantitation of thyroglossal tract thyroid tissue and total neck I-131 activity was performed using region of interest analysis on planar imaging following localisation on SPECT/CT. Results: thyroglossal tract thyroid tissue was present in 31/63 (49%; 95% CI: 37-61%) patients on SPECT/CT. In these 31 patients, thyroglossal tract thyroid tissue contributed to an average of 49% of total neck activity. Interobserver agreement was substantial on SPECT/CT (Kappa = 0.76; 95% CI: 0.61-0.91) and fair on planar imaging (Kappa = 0.31; 95% CI: 0.15-0.47). Conclusion: thyroid tissue along the thyroglossal tract was present in one half of patients in our study population and can contribute to a significant amount of total neck I-131 activity. Given the high prevalence of thyroglossal tract thyroid tissue, our results suggest that total neck

Role of post-therapy 131Iodine SPECT-CT in risk stratification and management of patients with differentiated thyroid cancer

International Nuclear Information System (INIS)

Agarwal, K.; Bhattacharya, A.; Harishankar, C.N.B.; Manohar, K.; Mittal, B.R.

2010-01-01

Full text: To determine whether post therapy 131 I SPECT/CT changed the American Thyroid Association risk of recurrence classification and further management of the patients with differentiated thyroid carcinoma. Materials and Methods: In this prospective study, 33 consecutive patients with thyroid carcinoma (28 papillary, 4 follicular, 1 Hurthle cell) were included. Planar imaging and SPECT/CT were performed 4-7 days after the therapeutic administration of 1,221-5,180 MBq (33-140 mCi) of 131 I. SPECT/CT of the neck and upper chest were obtained for all subjects. Additional SPECT/CT scans of the abdomen or pelvis were acquired if planar imaging showed any abnormal focus of uptake. Planar and SPECT/CT images were interpreted independently, and sites of uptake were categorized as residual thyroid uptake, level VI cervical lymph node uptake, level II-V cervical lymph nodal uptake or distant metastasis. An experienced nuclear medicine physician determined if the imaging findings changed the patient's risk category and further management. Results: In 4 of 33 post surgical patients, SPECT/CT findings changed the initial ATA risk of recurrence classification. In 3 of these 4 patients, WB planar imaging showed distant metastases (1 in lung, 1 in spleen, 1 in left humerus), SPECT/CT confirming these to physiological uptake in breast and intestine and skin contamination respectively. This altered the risk of recurrence from high to intermediate category. In 1 of these 4 patients, WB planar imaging was suggestive of cervical lymph nodal metastasis, but SPECT/CT localized the abnormal focus of uptake to residual thyroid tissue, altering the risk of recurrence from intermediate to low. SPECT/CT changed the further post ablation management in 13 out of 33 patients. In 4/13 patients SPECT/CT detected cervical lymph nodes metastases, in 1/13 patient supraclavicular lymph node metastasis was detected, in 7/13 patients distant metastases was confirmed as physiological uptake or

The application of DynaCT in performing the placement of intracranial stent

International Nuclear Information System (INIS)

Shen Hui; Wang Yongchun; Wang Minjie; Ding Hailing; Qin Yashan; Mao Yaqin; Li Songhua; Mao Yanjun; Hao Qiang

2011-01-01

Objective: To evaluate the clinical application of DynaCT technique in performing intracranial stent implantation. Methods: Thirty-nine patients who were planed to receive intracranial stent implantation were involved in this study. During the procedure DynaCT scanning was employed to monitor the real-time situation of stent implantation. Results: A total of 47 stents were implanted in intracranial vessels in the 39 patients. By using conventional angiography during operation the position of these stents was observed and was assured to be in the proper position. The adherence of these stents to the vascular wall was demonstrated with DynaCT multi-planar reconstruction images and the stent adherence in good condition was ensured. Conclusion: DynaCT applied during and after intracranial stent implantation is very helpful for displaying the contours of the stents as well as the vascular lumen and for providing a detail picture of the relationship between the stent and the surrounding anatomy. Therefore, DynaCT scanning is of great clinical significance for performing the intracranial stent implantation. (authors)

3D reconstruction from multi-view VHR-satellite images in MicMac

Science.gov (United States)

Rupnik, Ewelina; Pierrot-Deseilligny, Marc; Delorme, Arthur

2018-05-01

This work addresses the generation of high quality digital surface models by fusing multiple depths maps calculated with the dense image matching method. The algorithm is adapted to very high resolution multi-view satellite images, and the main contributions of this work are in the multi-view fusion. The algorithm is insensitive to outliers, takes into account the matching quality indicators, handles non-correlated zones (e.g. occlusions), and is solved with a multi-directional dynamic programming approach. No geometric constraints (e.g. surface planarity) or auxiliary data in form of ground control points are required for its operation. Prior to the fusion procedures, the RPC geolocation parameters of all images are improved in a bundle block adjustment routine. The performance of the algorithm is evaluated on two VHR (Very High Resolution)-satellite image datasets (Pléiades, WorldView-3) revealing its good performance in reconstructing non-textured areas, repetitive patterns, and surface discontinuities.

Optimization of SPECT-CT Hybrid Imaging Using Iterative Image Reconstruction for Low-Dose CT: A Phantom Study.

Directory of Open Access Journals (Sweden)

Oliver S Grosser

Full Text Available Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT or positron emission tomography (PET with computed tomography (CT. Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR on the image quality of the low-dose CT images.Examinations were performed with a SPECT-CT scanner with standardized CT and SPECT-phantom geometries and CT protocols with systematically reduced X-ray tube currents. Analyses included image quality with respect to photon flux. Results were compared to the standard FBP reconstructed images. The general impact of the CT-based attenuation maps used during SPECT reconstruction was examined for two SPECT phantoms. Using ASIR for image reconstructions, image noise was reduced compared to FBP reconstructions for the same X-ray tube current. The Hounsfield unit (HU values reconstructed by ASIR were correlated to the FBP HU values(R2 ≥ 0.88 and the contrast-to-noise ratio (CNR was improved by ASIR. However, for a phantom with increased attenuation, the HU values shifted for low X-ray tube currents I ≤ 60 mA (p ≤ 0.04. In addition, the shift of the HU values was observed within the attenuation corrected SPECT images for very low X-ray tube currents (I ≤ 20 mA, p ≤ 0.001.In general, the decrease in X-ray tube current up to 30 mA in combination with ASIR led to a reduction of CT-related radiation exposure without a significant decrease in image quality.

Comparative methods for quantifying thyroid volume using planar imaging and SPECT

International Nuclear Information System (INIS)

Zaidi, H.

1996-01-01

Thyroid volume determination using planar imaging is a procedure often performed in routine nuclear medicine, but is hampered by several physical difficulties, in particular by structures which overlie or underlie the organ of interest. SPECT enables improved accuracy over planar imaging in the determination of the volume since it is derived from the 3-D data rather than from a 2-D projection with a certain geometric assumption regarding the thyroid configuration. By using the phantoms of known volume, it was possible to estimate the accuracy of 3 different methods of determining thyroid volume from planar imaging used in clinical routine. The experimental results demonstrate that compared with conventional scintigraphy, thyroid phantom volumes were most accurately determined with SPECT when attenuation and scatter corrections are performed which allows accurate radiation dosimetry in humans without the need for assumptions on organ size or concentrations. Poster 181. (author)

Evaluation of hepatic alveolar echinococcosis with multi-slices spiral CT

International Nuclear Information System (INIS)

Liu Wenya; Lou Jianru; Xing Yan; Wang Jing; Wang Haitao

2005-01-01

Objective: To analyze the multi-slices spiral CT (MSCT) findings of hepatic alveolar echinococcosis (HAE), and to evaluate the value of MSCT for diagnosis of HAE. Methods: Twenty-six cases with HAE were scanning by MSCT. The raw data were transmitted to advanced workstation for reconstruction imaging. Correlated studies were made between the CT features and pathology or other imaging results. Results: Altogether 28 lesions were detected. They all revealed as heterogeneous hypodense mass with ill-defined boundary in plain CT but were easily being distinguished from surrounding parenchyma after contrast medium injection. Characteristics of the lesions include different amount of calcification (26/26), liquefied necrosis in center area (20/26), peripheral lacunae or alveolar signs (15/26 ), compensatory hypertrophy of healthy hepatic part (18/26) and the retraction in the involved hepatic lobe or segment (12/26). The lesions that located at or extended to hepatic hilum caused dilatation of intra-hepatic biliary ducts (9/26), splenomegaly (12/26 ), and ascites (1/26). MSCT angiography (CTA) depicted signs of abnormalities of hepatic vessels such as compression, displacement, encasement and occlusion. Compared with findings of operation, the sensitivity, specificity and positive prediction value of CTA for evaluating the hepatic artery system disorders were 88%, 96% and 93%, respectively; and for portal venous system were 95%, 100% and 95%, respectively; while for hepatic venous system were 96%, 86% and 96%, respectively. Conclusion: MSCT is able to comprehensive display the CT features and vessels complication of HAE. It provides reliable imaging for both accuracy diagnosis and proper treatment of the disease. (authors)

Primitive experience of three dimensional multi-slice spiral CT angiography for the follow-up of intracranial aneurysm clipping

International Nuclear Information System (INIS)

Yang Yunjun; Chen Weijian; Hu Zhangyong; Wu Enfu; Wang Meihao; Zhuge Qichuan; Zhongming; Cheng Jingliang; Ren Cuiping; Zhang Yong

2008-01-01

Objective To evaluate multi-slice three-dimensional CT angiography (MS 3D-CTA) for the follow-up of intracranial aneurysm clipping. Methods: MS 3D-CTA of 16 patients with intracranial aneurysm clipping were retrospectively analyzed. The patients were scanned on a 16-slice spiral CT (GE Lightspeed pro). Volume rendering(VR), thin maximum intensity projection(thin MIP) and multi-planar reconstruction (MPR) were employed in image postprocessing in all cases. Results: There were 17 clips in the 16 patients with aneurysm clipping. Six clips were located at the posterior communicating artery, 5 at the anterior communicating artery, 4 at the middle cerebral artery, and the remaining 2 clips were located at the pericallosal artery, in 1 patient. There were no abnormalities found in the aneurysm clipping region in 7 cases by MS 3D- CTA. There were residual aneurysm in 2 cases, parent artery stenosis in 4 cases, and artery spasm in 3 eases. There was no parent artery occlusion and clip displacement in all cases. VR showed excellent 3D spacial relations between the clip and parent artery in 12 cases, and showed good relations in 3 cases. The 1 case with 2 clips in the pericallosal artery showed heavy beam-hardening artifacts. The size and shape of aneurysm clips were clearly depicted by MPR and thin MIP, while 3D spacial relation of aneurysm clip and parent artery were poorly showed. Conclusion: MS 3D-CTA is a safe and efficient method for the follow-up of intracranialaneurysm clipping. Combined VR with MPR or thin MIP can well reveal postoperative changes after aneurysm clipping. (authors)

The experimental study on bowel ischemia in closed loop obstruction by using multi-phase spiral CT

International Nuclear Information System (INIS)

Zhang Xiaoming; Yang Hanfeng; Huang Xiaohua; Tang Xianying; Jian Pu; Yang Zhengwei; Zhou Jiyong; Zhao Zongwen

2005-01-01

Objective: To evaluate the bowel ischemia in experimental closed loop obstruction by using multi-phase spiral CT. Methods: Twenty-four New Zealand rabbits of both sexes (mean age, 4 months, and mean body weight, 2.5-3.0 kg) were divided randomly into three groups with each group containing 8 rabbits. After clamping 10-15 cm segments of small bowel and their veins for 0.5 hours (Group A), 1-2 hours (Group B), and 3-5 hours (Group C), respectively, multi-phase spiral CT was performed at baseline, and at arterial, venous, and delayed phases after intravenous contrast administration. Then the rabbits were sacrificed to observe their surgical and histological changes. Two radiologists, blinded to the animal model classification and their histological results, individually reviewed the CT images to observe the CT appearances of the closed loop. Statistical significance criteria was determined by P 0.05) at baseline, however, they were significantly different (P<0.05) at all phases after enhancement. Among rabbits without necrotic closed loop, 11 of 13 had continuous enhancement at all phases, while only 1 of 11 rabbits with necrotic closed loop showed continuous enhancement (P<0.05). Conclusion: The ischemia of bowel wall in different phases after clamping small bowel and their veins can be evaluated by using enhanced multi-phase spiral CT. Continuous enhancement of bowel wall in multi-phase spiral CT can be seen prominently in the early bowel ischemia, but necrotic bowel shows no enhancement. (authors)

The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients

International Nuclear Information System (INIS)

Nielsen, Kristina Rue; Nielsen, Michael B.; Chakera, Annette H.; Hesse, Birger; Oturai, Peter S.; Scolyer, Richard A.; Stretch, Jonathan F.; Thompson, John F.; Uren, Roger F.

2011-01-01

The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients. Three hundred and seven consecutive melanoma patients referred for SN biopsy (SNB) were examined using combined imaging. Secondary interpretation of only the delayed static images was subsequently performed. In 220 patients (72%), complete surgical and pathological information relating to the SNB was available. The number of SNs identified and number of patients with positive SNs were compared between the two interpretations of the imaging studies and, when available, related to pathology data. A slightly higher number of SNs (mean 0.12/patient) was identified when interpreting only delayed static images compared to combined imaging. In a direct patient-to-patient comparison, the number of SN(s) identified on the combined vs static images only showed moderate agreement (kappa value 0.56). In 38 patients (17%), positive SNs were identified by the combined procedure compared to 35 (16%) by static imaging only. Thus by static imaging only, tumour-positive SNs were not identified in 3 of 38 patients (8%). For SN identification in melanoma patients, dynamic imaging combined with delayed static imaging and SPECT/CT is superior to delayed static imaging only because the latter is more likely to fail to identify SNs containing metastases. (orig.)

Extraperitoneal urine leak after renal transplantation: the role of radionuclide imaging and the value of accompanying SPECT/CT - a case report

International Nuclear Information System (INIS)

Son, Hongju; Heiba, Sherif; Kostakoglu, Lale; Machac, Josef

2010-01-01

The differentiation of the nature of a fluid collection as a complication of kidney transplantation is important for management and treatment planning. Early and delayed radionuclide renography can play an important role in the evaluation of a urine leak. However, it is sometimes limited in the evaluation of the exact location and extent of a urine leak. A 71-year-old male who had sudden anuria, scrotal swelling and elevated creatinine level after cadaveric renal transplantation performed Tc-99 m MAG3 renography to evaluate the renal function, followed by an ultrasound which was unremarkable. An extensive urine leak was evident on the planar images. However, an exact location of the urine leak was unknown. Accompanying SPECT/CT images confirmed a urine leak extending from the lower aspect of the transplant kidney to the floor of the pelvic cavity, presacral region and the scrotum via right inguinal canal as well as to the right abdominal wall. Renal scintigraphy is very useful to detect a urine leak after renal transplantation. However, planar imaging is sometimes limited in evaluating the anatomical location and extent of a urine leak accurately. In that case accompanying SPECT/CT images are very helpful and valuable to evaluate the anatomical relationships exactly

Coronary artery anomalies in adults: imaging at dual source CT coronary angiography

International Nuclear Information System (INIS)

Laspas, Fotios; Roussakis, Arkadios; Mourmouris, Christos; Kritikos, Nikolaos; Efthimiadou, Roxani; Andreou, John

2013-01-01

Congenital abnormalities of the coronary arteries have an incidence of 1%, and most of these are benign. However, a small number are associated with myocardial ischaemia and sudden death. Various imaging modalities are available for coronary artery assessment. Recently, multi-detector CT has emerged as an accurate diagnostic tool for defining coronary artery anomalies. The purpose of this pictorial essay is to review the dual source CT appearance of congenital anomalies of the coronary arteries in adults.

Implications of CT noise and artifacts for quantitative 99mTc SPECT/CT imaging

International Nuclear Information System (INIS)

Hulme, K. W.; Kappadath, S. C.

2014-01-01

Purpose: This paper evaluates the effects of computed tomography (CT) image noise and artifacts on quantitative single-photon emission computed-tomography (SPECT) imaging, with the aim of establishing an appropriate range of CT acquisition parameters for low-dose protocols with respect to accurate SPECT attenuation correction (AC). Methods: SPECT images of two geometric and one anthropomorphic phantom were reconstructed iteratively using CT scans acquired at a range of dose levels (CTDI vol = 0.4 to 46 mGy). Resultant SPECT image quality was evaluated by comparing mean signal, background noise, and artifacts to SPECT images reconstructed using the highest dose CT for AC. Noise injection was performed on linear-attenuation (μ) maps to determine the CT noise threshold for accurate AC. Results: High levels of CT noise (σ ∼ 200–400 HU) resulted in low μ-maps noise (σ ∼ 1%–3%). Noise levels greater than ∼10% in 140 keV μ-maps were required to produce visibly perceptible increases of ∼15% in 99m Tc SPECT images. These noise levels would be achieved at low CT dose levels (CTDI vol = 4 μGy) that are over 2 orders of magnitude lower than the minimum dose for diagnostic CT scanners. CT noise could also lower (bias) the expected μ values. The relative error in reconstructed SPECT signal trended linearly with the relative shift in μ. SPECT signal was, on average, underestimated in regions corresponding with beam-hardening artifacts in CT images. Any process that has the potential to change the CT number of a region by ∼100 HU (e.g., misregistration between CT images and SPECT images due to motion, the presence of contrast in CT images) could introduce errors in μ 140 keV on the order of 10%, that in turn, could introduce errors on the order of ∼10% into the reconstructed 99m Tc SPECT image. Conclusions: The impact of CT noise on SPECT noise was demonstrated to be negligible for clinically achievable CT parameters. Because CT dose levels that affect

Computer-assisted lung nodule volumetry from multi-detector row CT: Influence of image reconstruction parameters

International Nuclear Information System (INIS)

Honda, Osamu; Sumikawa, Hiromitsu; Johkoh, Takeshi; Tomiyama, Noriyuki; Mihara, Naoki; Inoue, Atsuo; Tsubamoto, Mitsuko; Natsag, Javzandulam; Hamada, Seiki; Nakamura, Hironobu

2007-01-01

Purpose: To investigate differences in volumetric measurement of pulmonary nodules caused by changing the reconstruction parameters for multi-detector row CT. Materials and methods: Thirty-nine pulmonary nodules less than 2 cm in diameter were examined by multi-slice CT. All nodules were solid, and located in the peripheral part of the lungs. The resultant 48 parameters images were reconstructed by changing slice thickness (1.25, 2.5, 3.75, or 5 mm), field of view (FOV: 10, 20, or 30 cm), algorithm (high-spatial frequency algorithm or low-spatial frequency algorithm) and reconstruction interval (reconstruction with 50% overlapping of the reconstructed slices or non-overlapping reconstruction). Volumetric measurements were calculated using commercially available software. The differences between nodule volumes were analyzed by the Kruskal-Wallis test and the Wilcoxon Signed-Ranks test. Results: The diameter of the nodules was 8.7 ± 2.7 mm on average, ranging from 4.3 to 16.4 mm. Pulmonary nodule volume did not change significantly with changes in slice thickness or FOV (p > 0.05), but was significantly larger with the high-spatial frequency algorithm than the low-spatial frequency algorithm (p < 0.05), except for one reconstruction parameter. The volumes determined by non-overlapping reconstruction were significantly larger than those of overlapping reconstruction (p < 0.05), except for a 1.25 mm thickness with 10 cm FOV with the high-spatial frequency algorithm, and 5 mm thickness. The maximum difference in measured volume was 16% on average between the 1.25 mm slice thickness/10 cm FOV/high-spatial frequency algorithm parameters and overlapping reconstruction. Conclusion: Volumetric measurements of pulmonary nodules differ with changes in the reconstruction parameters, with a tendency toward larger volumes in high-spatial frequency algorithm and non-overlapping reconstruction compared to the low-spatial frequency algorithm and overlapping reconstruction

SPECT/CT and pulmonary embolism

DEFF Research Database (Denmark)

Mortensen, Jann; Borgwardt, Henrik Gutte

2014-01-01

the best diagnostic accuracy for PE. In addition, recent developments in the CTPA technique have made it possible to image the pulmonary arteries of the lungs in one breath-hold. This development is based on the change from a single-detector to multidetector CT technology with an increase in volume......Acute pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/P) scintigraphy or pulmonary CT angiography (CTPA). In recent years both techniques have improved. Many nuclear medicine centres have adopted the single photon emission CT (SPECT) technique as opposed to the planar...

Vertebral uptake of Tc-99m macroaggregated albumin (MAA) with SPECT/CT occurring in superior vena cava obstruction

Energy Technology Data Exchange (ETDEWEB)

Karls, Shawn; Hassoun, Hani; Derbekyan, Vilma [Dept. of Nuclear Madicine, Royal Victoria Hospital, Montreal (Canada)

2016-09-15

A 67-year-old male presented with dyspnea for which lung scintigraphy was ordered to rule out pulmonary embolus. Planar images demonstrated abnormal midline uptake of Tc-99m macroaggregated albumin, which SPECT/CT localized to several thoracic vertebrae. Thoracic vertebral uptake on perfusion lung scintigraphy was previously described on planar imaging. Radionuclide venography and contrast-enhanced CT subsequently demonstrated superior vena cava (SVC) obstruction with collateralization through the azygous/hemiazygous system and vertebral venous plexus. SPECT/CT differentiated residual esophageal/tracheal ventilation activity, a clinically insignificant finding, from vertebral uptake indicative of SVC obstruction, a potentially life-threatening condition.

SPECT/CT workflow and imaging protocols

Energy Technology Data Exchange (ETDEWEB)

Beckers, Catherine [University Hospital of Liege, Division of Nuclear Medicine and Oncological Imaging, Department of Medical Physics, Liege (Belgium); Hustinx, Roland [University Hospital of Liege, Division of Nuclear Medicine and Oncological Imaging, Department of Medical Physics, Liege (Belgium); Domaine Universitaire du Sart Tilman, Service de Medecine Nucleaire et Imagerie Oncologique, CHU de Liege, Liege (Belgium)

2014-05-15

Introducing a hybrid imaging method such as single photon emission computed tomography (SPECT)/CT greatly alters the routine in the nuclear medicine department. It requires designing new workflow processes and the revision of original scheduling process and imaging protocols. In addition, the imaging protocol should be adapted for each individual patient, so that performing CT is fully justified and the CT procedure is fully tailored to address the clinical issue. Such refinements often occur before the procedure is started but may be required at some intermediate stage of the procedure. Furthermore, SPECT/CT leads in many instances to a new partnership with the radiology department. This article presents practical advice and highlights the key clinical elements which need to be considered to help understand the workflow process of SPECT/CT and optimise imaging protocols. The workflow process using SPECT/CT is complex in particular because of its bimodal character, the large spectrum of stakeholders, the multiplicity of their activities at various time points and the need for real-time decision-making. With help from analytical tools developed for quality assessment, the workflow process using SPECT/CT may be separated into related, but independent steps, each with its specific human and material resources to use as inputs or outputs. This helps identify factors that could contribute to failure in routine clinical practice. At each step of the process, practical aspects to optimise imaging procedure and protocols are developed. A decision-making algorithm for justifying each CT indication as well as the appropriateness of each CT protocol is the cornerstone of routine clinical practice using SPECT/CT. In conclusion, implementing hybrid SPECT/CT imaging requires new ways of working. It is highly rewarding from a clinical perspective, but it also proves to be a daily challenge in terms of management. (orig.)

SPECT/CT workflow and imaging protocols

International Nuclear Information System (INIS)

Beckers, Catherine; Hustinx, Roland

2014-01-01

Introducing a hybrid imaging method such as single photon emission computed tomography (SPECT)/CT greatly alters the routine in the nuclear medicine department. It requires designing new workflow processes and the revision of original scheduling process and imaging protocols. In addition, the imaging protocol should be adapted for each individual patient, so that performing CT is fully justified and the CT procedure is fully tailored to address the clinical issue. Such refinements often occur before the procedure is started but may be required at some intermediate stage of the procedure. Furthermore, SPECT/CT leads in many instances to a new partnership with the radiology department. This article presents practical advice and highlights the key clinical elements which need to be considered to help understand the workflow process of SPECT/CT and optimise imaging protocols. The workflow process using SPECT/CT is complex in particular because of its bimodal character, the large spectrum of stakeholders, the multiplicity of their activities at various time points and the need for real-time decision-making. With help from analytical tools developed for quality assessment, the workflow process using SPECT/CT may be separated into related, but independent steps, each with its specific human and material resources to use as inputs or outputs. This helps identify factors that could contribute to failure in routine clinical practice. At each step of the process, practical aspects to optimise imaging procedure and protocols are developed. A decision-making algorithm for justifying each CT indication as well as the appropriateness of each CT protocol is the cornerstone of routine clinical practice using SPECT/CT. In conclusion, implementing hybrid SPECT/CT imaging requires new ways of working. It is highly rewarding from a clinical perspective, but it also proves to be a daily challenge in terms of management. (orig.)

Multi-technique hybrid imaging in PET/CT and PET/MR: what does the future hold?

International Nuclear Information System (INIS)

Galiza Barbosa, F. de; Delso, G.; Voert, E.E.G.W. ter; Huellner, M.W.; Herrmann, K.; Veit-Haibach, P.

2016-01-01

Integrated positron-emission tomography and computed tomography (PET/CT) is one of the most important imaging techniques to have emerged in oncological practice in the last decade. Hybrid imaging, in general, remains a rapidly growing field, not only in developing countries, but also in western industrialised healthcare systems. A great deal of technological development and research is focused on improving hybrid imaging technology further and introducing new techniques, e.g., integrated PET and magnetic resonance imaging (PET/MRI). Additionally, there are several new PET tracers on the horizon, which have the potential to broaden clinical applications in hybrid imaging for diagnosis as well as therapy. This article aims to highlight some of the major technical and clinical advances that are currently taking place in PET/CT and PET/MRI that will potentially maintain the position of hybrid techniques at the forefront of medical imaging technologies.

3D visualisation of the middle ear and adjacent structures using reconstructed multi-slice CT datasets, correlating 3D images and virtual endoscopy to the 2D cross-sectional images

International Nuclear Information System (INIS)

Rodt, T.; Ratiu, P.; Kacher, D.F.; Anderson, M.; Jolesz, F.A.; Kikinis, R.; Becker, H.; Bartling, S.

2002-01-01

The 3D imaging of the middle ear facilitates better understanding of the patient's anatomy. Cross-sectional slices, however, often allow a more accurate evaluation of anatomical structures, as some detail may be lost through post-processing. In order to demonstrate the advantages of combining both approaches, we performed computed tomography (CT) imaging in two normal and 15 different pathological cases, and the 3D models were correlated to the cross-sectional CT slices. Reconstructed CT datasets were acquired by multi-slice CT. Post-processing was performed using the in-house software ''3D Slicer'', applying thresholding and manual segmentation. 3D models of the individual anatomical structures were generated and displayed in different colours. The display of relevant anatomical and pathological structures was evaluated in the greyscale 2D slices, 3D images, and the 2D slices showing the segmented 2D anatomy in different colours for each structure. Correlating 2D slices to the 3D models and virtual endoscopy helps to combine the advantages of each method. As generating 3D models can be extremely time-consuming, this approach can be a clinically applicable way of gaining a 3D understanding of the patient's anatomy by using models as a reference. Furthermore, it can help radiologists and otolaryngologists evaluating the 2D slices by adding the correct 3D information that would otherwise have to be mentally integrated. The method can be applied to radiological diagnosis, surgical planning, and especially, to teaching. (orig.)

Automatic recognition of 3D GGO CT imaging signs through the fusion of hybrid resampling and layer-wise fine-tuning CNNs.

Science.gov (United States)

Han, Guanghui; Liu, Xiabi; Zheng, Guangyuan; Wang, Murong; Huang, Shan

2018-06-06

Ground-glass opacity (GGO) is a common CT imaging sign on high-resolution CT, which means the lesion is more likely to be malignant compared to common solid lung nodules. The automatic recognition of GGO CT imaging signs is of great importance for early diagnosis and possible cure of lung cancers. The present GGO recognition methods employ traditional low-level features and system performance improves slowly. Considering the high-performance of CNN model in computer vision field, we proposed an automatic recognition method of 3D GGO CT imaging signs through the fusion of hybrid resampling and layer-wise fine-tuning CNN models in this paper. Our hybrid resampling is performed on multi-views and multi-receptive fields, which reduces the risk of missing small or large GGOs by adopting representative sampling panels and processing GGOs with multiple scales simultaneously. The layer-wise fine-tuning strategy has the ability to obtain the optimal fine-tuning model. Multi-CNN models fusion strategy obtains better performance than any single trained model. We evaluated our method on the GGO nodule samples in publicly available LIDC-IDRI dataset of chest CT scans. The experimental results show that our method yields excellent results with 96.64% sensitivity, 71.43% specificity, and 0.83 F1 score. Our method is a promising approach to apply deep learning method to computer-aided analysis of specific CT imaging signs with insufficient labeled images. Graphical abstract We proposed an automatic recognition method of 3D GGO CT imaging signs through the fusion of hybrid resampling and layer-wise fine-tuning CNN models in this paper. Our hybrid resampling reduces the risk of missing small or large GGOs by adopting representative sampling panels and processing GGOs with multiple scales simultaneously. The layer-wise fine-tuning strategy has ability to obtain the optimal fine-tuning model. Our method is a promising approach to apply deep learning method to computer-aided analysis

Dynamic multi-coil technique (DYNAMITE) shimming for echo-planar imaging of the human brain at 7 Tesla.

Science.gov (United States)

Juchem, Christoph; Umesh Rudrapatna, S; Nixon, Terence W; de Graaf, Robin A

2015-01-15

Gradient-echo echo-planar imaging (EPI) is the primary method of choice in functional MRI and other methods relying on fast MRI to image brain activation and connectivity. However, the high susceptibility of EPI towards B0 magnetic field inhomogeneity poses serious challenges. Conventional magnetic field shimming with low-order spherical harmonic (SH) functions is capable of compensating shallow field distortions, but performs poorly for global brain shimming or on specific areas with strong susceptibility-induced B0 distortions such as the prefrontal cortex (PFC). Excellent B0 homogeneity has been demonstrated recently in the human brain at 7 Tesla with the DYNAmic Multi-coIl TEchnique (DYNAMITE) for magnetic field shimming (J Magn Reson (2011) 212:280-288). Here, we report the benefits of DYNAMITE shimming for multi-slice EPI and T2* mapping. A standard deviation of 13Hz was achieved for the residual B0 distribution in the human brain at 7 Tesla with DYNAMITE shimming and was 60% lower compared to conventional shimming that employs static zero through third order SH shapes. The residual field inhomogeneity with SH shimming led to an average 8mm shift at acquisition parameters commonly used for fMRI and was reduced to 1.5-3mm with DYNAMITE shimming. T2* values obtained from the prefrontal and temporal cortices with DYNAMITE shimming were 10-50% longer than those measured with SH shimming. The reduction of the confounding macroscopic B0 field gradients with DYNAMITE shimming thereby promises improved access to the relevant microscopic T2* effects. The combination of high spatial resolution and DYNAMITE shimming allows largely artifact-free EPI and T2* mapping throughout the brain, including prefrontal and temporal lobe areas. DYNAMITE shimming is expected to critically benefit a wide range of MRI applications that rely on excellent B0 magnetic field conditions including EPI-based fMRI to study various cognitive processes and assessing large-scale brain connectivity

Dynamic Multi-Coil Technique (DYNAMITE) Shimming for Echo-Planar Imaging of the Human Brain at 7 Tesla

Science.gov (United States)

Juchem, Christoph; Rudrapatna, S. Umesh; Nixon, Terence W.; de Graaf, Robin A.

2014-01-01

Gradient-echo echo-planar imaging (EPI) is the primary method of choice in functional MRI and other methods relying on fast MRI to image brain activation and connectivity. However, the high susceptibility of EPI towards B0 magnetic field inhomogeneity poses serious challenges. Conventional magnetic field shimming with low-order spherical harmonic (SH) functions is capable of compensating shallow field distortions, but performs poorly for global brain shimming or on specific areas with strong susceptibility-induced B0 distortions such as the prefrontal cortex (PFC). Excellent B0 homogeneity has been demonstrated recently in the human brain at 7 Tesla with the DYNAmic Multi-coIl TEchnique (DYNAMITE) for magnetic field shimming (Juchem et al., J Magn Reson (2011) 212:280-288). Here, we report the benefits of DYNAMITE shimming for multi-slice EPI and T2* mapping. A standard deviation of 13 Hz was achieved for the residual B0 distribution in the human brain at 7 Tesla with DYNAMITE shimming and was 60% lower compared to conventional shimming that employs static zero through third order SH shapes. The residual field inhomogeneity with SH shimming led to an average 8 mm shift at acquisition parameters commonly used for fMRI and was reduced to 1.5-3 mm with DYNAMITE shimming. T2* values obtained from the prefrontal and temporal cortices with DYNAMITE shimming were 10-50% longer than those measured with SH shimming. The reduction of the confounding macroscopic B0 field gradients with DYNAMITE shimming thereby promises improved access to the relevant microscopic T2* effects. The combination of high spatial resolution and DYNAMITE shimming allows largely artifact-free EPI and T2* mapping throughout the brain, including prefrontal and temporal lobe areas. DYNAMITE shimming is expected to critically benefit a wide range of MRI applications that rely on excellent B0 magnetic field conditions including EPI-based fMRI to study various cognitive processes and assessing large

Usefulness of simulation with multi-slice CT for laparoscopic nephrectomy

Energy Technology Data Exchange (ETDEWEB)

Akiyama, Yuji; Ishifuro, Minoru; Ookubo, Masaomi [Hiroshima Univ. (Japan). Hospital] (and others)

2002-12-01

In recent years, laparoscopic surgery has attracted attention as a minimally invasive type of surgery because of the small surgical wounds and early recovery it provides. We carry out this technique on the basis of volume data that we make use of in multi-slice CT imaging technology in laparoscopic nephrectomy by the retroperitoneal approach, and we have created CT virtual laparoscopy by virtual endoscopic display as an intra-operative navigator with an image analysis system. We provide information on detailed vascular anatomy to form intra-operative images that act as similar support images. With the provision of this volume data, we consider virtual endoscopic display the most suitable method for surgery. When we perform virtual laparoscopy, we simulate the insertion point and angle, the order of vascular structures and their locations, the number of arteries and veins, and their bifurcation points and ligation points in conjunction with the surgeon prior to operation. As the branch patterns of the renal artery are varied, perioperative confusion and surgical mishaps can be avoided through the information that is provided beforehand. Thus surgery is more accurate and proceeds more smoothly, because the surgeon has accurate anatomical information. In addition, the time required for surgery is decreased, reducing risk and the possibility of complications. (author)

Usefulness of simulation with multi-slice CT for laparoscopic nephrectomy

International Nuclear Information System (INIS)

Akiyama, Yuji; Ishifuro, Minoru; Ookubo, Masaomi

2002-01-01

In recent years, laparoscopic surgery has attracted attention as a minimally invasive type of surgery because of the small surgical wounds and early recovery it provides. We carry out this technique on the basis of volume data that we make use of in multi-slice CT imaging technology in laparoscopic nephrectomy by the retroperitoneal approach, and we have created CT virtual laparoscopy by virtual endoscopic display as an intra-operative navigator with an image analysis system. We provide information on detailed vascular anatomy to form intra-operative images that act as similar support images. With the provision of this volume data, we consider virtual endoscopic display the most suitable method for surgery. When we perform virtual laparoscopy, we simulate the insertion point and angle, the order of vascular structures and their locations, the number of arteries and veins, and their bifurcation points and ligation points in conjunction with the surgeon prior to operation. As the branch patterns of the renal artery are varied, perioperative confusion and surgical mishaps can be avoided through the information that is provided beforehand. Thus surgery is more accurate and proceeds more smoothly, because the surgeon has accurate anatomical information. In addition, the time required for surgery is decreased, reducing risk and the possibility of complications. (author)

Scatter correction, intermediate view estimation and dose characterization in megavoltage cone-beam CT imaging

Science.gov (United States)

Sramek, Benjamin Koerner

neck phantoms. The conclusions of this investigation were: (1) the implementation of intermediate view estimation techniques to megavoltage cone-beam CT produced improvements in image quality, with the largest impact occurring for smaller numbers of initially-acquired projections, (2) the SPECS scatter correction algorithm could be successfully incorporated into projection data acquired using an electronic portal imaging device during megavoltage cone-beam CT image reconstruction, (3) a large range of SPECS parameters were shown to reduce cupping artifacts as well as improve reconstruction accuracy, with application to anthropomorphic phantom geometries improving the percent difference in reconstructed electron density for soft tissue from -13.6% to -2.0%, and for cortical bone from -9.7% to 1.4%, (4) dose measurements in the anthropomorphic phantoms showed consistent agreement between planar measurements using radiochromic film and point measurements using thermoluminescent dosimeters, and (5) a comparison of normalized dose measurements acquired with radiochromic film to those calculated using multiple treatment planning systems, accelerator-detector combinations, patient geometries and accelerator outputs produced a relatively good agreement.

Clinical PET/CT imaging. Promises and misconceptions

International Nuclear Information System (INIS)

Czernin, J.; Auerbach, M.A.

2005-01-01

PET/CT is now established as the most important imaging tool in oncology. PET/CT stages and restages cancer with a higher accuracy than PET or CT alone. The sometimes irrational approach to combine state of the art PET with the highest end CT devices should give way to a more reasonable equipment design tailored towards the specific clinical indications in well-defined patient populations. The continuing success of molecular PET/CT now depends more upon advances in molecular imaging with the introduction of targeted imaging probes for individualized therapy approaches in cancer patients and less upon technological advances of imaging equipment. (orig.)

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

Science.gov (United States)

Lechuga, Lawrence; Weidlich, Georg A

2016-09-12

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

Three-dimensional reconstruction of CT images

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Toshiaki; Kattoh, Keiichi; Kawakami, Genichiroh; Igami, Isao; Mariya, Yasushi; Nakamura, Yasuhiko; Saitoh, Yohko; Tamura, Koreroku; Shinozaki, Tatsuyo

1986-09-01

Computed tomography (CT) has the ability to provide sensitive visualization of organs and lesions. Owing to the nature of CT to be transaxial images, a structure which is greater than a certain size appears as several serial CT images. Consequently each observer must reconstruct those images into a three-dimensional (3-D) form mentally. It has been supposed to be of great use if such a 3-D form can be described as a definite figure. A new computer program has been developed which can produce 3-D figures from the profiles of organs and lesions on CT images using spline curves. The figures obtained through this method are regarded to have practical applications.

Evaluation of the retrospective ECG-gated helical scan using half-second multi-slice CT. Motion phantom study for volumetry

International Nuclear Information System (INIS)

Yamamoto, Shuji; Matsumoto, Takashi; Nakanishi, Shohzoh; Hamada, Seiki; Takahei, Kazunari; Naito, Hiroaki; Ogata, Yuji

2002-01-01

ECG synchronized technique on multi-slice CT provide the thinner (less 2 mm slice thickness) and faster (0.5 sec/rotation) scan than that of the single detector CT and can acquire the coverage of the entire heart volume within one breath-hold. However, temporal resolution of multi-slice CT is insufficient on practical range of heart rate. The purpose of this study was to evaluate the accuracy of volumetry on cardiac function measurement in retrospective ECG-gated helical scan. We discussed the influence of the degradation of image quality and limitation of the heart rate in cardiac function measurement (volumetry) using motion phantom. (author)

Planar Submillimeter-Wave Mixer Technology with Integrated Antenna

Science.gov (United States)

Chattopadhyay, Gautam; Mehdi, Imran; Gill, John J.; Lee, Choonsup; lombart, Muria L.; Thomas, Betrand

2010-01-01

High-performance mixers at terahertz frequencies require good matching between the coupling circuits such as antennas and local oscillators and the diode embedding impedance. With the availability of amplifiers at submillimeter wavelengths and the need to have multi-pixel imagers and cameras, planar mixer architecture is required to have an integrated system. An integrated mixer with planar antenna provides a compact and optimized design at terahertz frequencies. Moreover, it leads to a planar architecture that enables efficient interconnect with submillimeter-wave amplifiers. In this architecture, a planar slot antenna is designed on a thin gallium arsenide (GaAs) membrane in such a way that the beam on either side of the membrane is symmetric and has good beam profile with high coupling efficiency. A coplanar waveguide (CPW) coupled Schottky diode mixer is designed and integrated with the antenna. In this architecture, the local oscillator (LO) is coupled through one side of the antenna and the RF from the other side, without requiring any beam sp litters or diplexers. The intermediate frequency (IF) comes out on a 50-ohm CPW line at the edge of the mixer chip, which can be wire-bonded to external circuits. This unique terahertz mixer has an integrated single planar antenna for coupling both the radio frequency (RF) input and LO injection without any diplexer or beamsplitters. The design utilizes novel planar slot antenna architecture on a 3- mthick GaAs membrane. This work is required to enable future multi-pixel terahertz receivers for astrophysics missions, and lightweight and compact receivers for planetary missions to the outer planets in our solar system. Also, this technology can be used in tera hertz radar imaging applications as well as for testing of quantum cascade lasers (QCLs).

Imaging of head and neck tumors -- methods: CT, spiral-CT, multislice-spiral-CT

International Nuclear Information System (INIS)

Baum, Ulrich; Greess, Holger; Lell, Michael; Noemayr, Anton; Lenz, Martin

2000-01-01

Spiral-CT is standard for imaging neck tumors. In correspondence with other groups we routinely use spiral-CT with thin slices (3 mm), a pitch of 1.3-1.5 and an overlapping reconstruction increment (2-3 mm). In patients with dental fillings a short additional spiral parallel to the corpus of the mandible reduces artifacts behind the dental arches and improves the diagnostic value of CT. For the assessment of the base of the skull, the orbital floor, the palate and paranasal sinuses an additional examination in the coronal plane is helpful. Secondary coronal reconstructions of axial scans are helpful in the evaluation of the crossing of the midline by small tumors of the tongue base or palate. For an optimal vascular or tissue contrast a sufficient volume of contrast medium and a start delay greater than 70-80 s are necessary. In our opinion the best results can be achieved with a volume of 150 ml, a flow of 2.5 ml/s and a start delay of 80 s. Dynamic enhanced CT is only necessary in some special cases. There is clear indication for dynamic enhanced CT where a glomus tumor is suspected. Additional functional CT imaging during i-phonation and/or Valsalva's maneuver are of great importance to prove vocal cords mobility. Therefore, imaging during i-phonation is an elemental part of every thorough examination of the hypopharynx and larynx region. Multislice-spiral-CT allows almost isotropic imaging of the head and neck region and improves the assessment of tumor spread and lymph node metastases in arbitrary oblique planes. Thin structures (the base of the skull, the orbital floor, the hard palate) as well as the floor of the mouth can be evaluated sufficiently with multiplanar reformations. Usually, additional coronal scanning is not necessary with multislice-spiral-CT. Multislice-spiral-CT is especially advantageous in defining the critical relationships of tumor and lymph node metastases and for functional imaging of the hypopharynx and larynx not only in the

Comparative study of multi-slice spiral CT angiography and color doppler ultrasound in diagnosis of arteriosclerotic occlusive disease of lower extremity

International Nuclear Information System (INIS)

Li Wanjun; Lai Zhenhui; Cui Dong; Lin Xiupeng; Du Muxuan

2010-01-01

Objective: To compare the difference between multi-slice spiral CT angiography (MSCTA) and color doppler ultrasound in diagnosis of arteriosclerotic occlusive disease of lower extremity. Methods: Patients with arteriosclerosis occlusion were assessed by color doppler ultrasound, multi-slice spiral CT angiography and digital subtraction angiography (DSA). The image information of color doppler ultrasound and MSCTA were compared with that of DSA. Results: Color doppler ultrasound showed the anatomical shape and hemodynamics of the arteries of lower extremity. The sensitivity, specificity, and accuracy for diagnosis arteriosclerotic occlusive disease of lower extremity were 88.04%, 90.69% and 88.77% respectively. MSCTA showed the three dimensional structure of the arteries of lower extremity as well as the collateral arteries and the distal arterials. The sensitivity, specificity and accuracy of MSCTA were 97.69%, 96.90% and 97.66%, respectively. Conclusion: Multi-slice spiral CT angiography is an ideal imaging method for the diagnosis of arteriosclerotic occlusive disease of lower extremity. (authors)

Cardiac CT for the assessment of chest pain: Imaging techniques and clinical results

International Nuclear Information System (INIS)

Becker, Hans-Christoph; Johnson, Thorsten

2012-01-01

Immediate and efficient risk stratification and management of patients with acute chest pain in the emergency department is challenging. Traditional management of these patients includes serial ECG, laboratory tests and further on radionuclide perfusion imaging or ECG treadmill testing. Due to the advances of multi-detector CT technology, dedicated coronary CT angiography provides the potential to rapidly and reliably diagnose or exclude acute coronary artery disease. Life-threatening causes of chest pain, such as aortic dissection and pulmonary embolism can simultaneously be assessed with a single scan, sometimes referred to as “triple rule out” scan. With appropriate patient selection, cardiac CT can accurately diagnose heart disease or other sources of chest pain, markedly decrease health care costs, and reliably predict clinical outcomes. This article reviews imaging techniques and clinical results for CT been used to evaluate patients with chest pain entering the emergency department.

Planar concentrators at the étendue limit

Science.gov (United States)

Winston, Roland; Gordon, Jeffrey M.

2005-08-01

Recently proposed aplanatic imaging designs are integrally combined with nonimaging flux boosters to produce an ultra-compact planar dielectric-filled concentrator that performs near the étendue limit. Such optical devices are attractive for high-efficiency multi-junction photovoltaics at high flux, with realistic power generation of 1 W from a 1 mm2 cell.

The findings and the role of axial CT imaging and 3D imaging of gastric lesion by spiral CT

International Nuclear Information System (INIS)

Lee, Dong Ho; Ko, Young Tae

1996-01-01

The purpose of this study is to assess the efficacy of axial CT imaging and 3D imaging by spiral CT in the detection and evaluation of gastric lesion. Seventy-seven patients with pathologically-proven gastric lesions underwent axial CT and 3D imaging by spiral CT. There were 49 cases of advanced gastric carcinoma(AGC), 21 of early gastric carcinoma (EGC), three of benign ulcers, three of leiomyomas, and one case of lymphoma. Spiral CT was performed with 3-mm collimation, 4.5mm/sec table feed, and 1-1.5-mm reconstruction interval after the ingestion of gas. 3D imaging was obtained using the SSD technique, and on analysis a grade was given(excellent, good, poor). Axial CT scan was performed with 5-mm collimation, 7mm/sec table feed, and 5-mm reconstruction interval after the ingestion of water. Among 49 cases of AGC, excellent 3D images were obtained in seven patients (14.3%), good 3D images in 30(61.2%), and poor 3D images in 12(24.5%). Among the 12 patients with poor images, the cancers were located at the pyloric antrum in eight cases, were AGC Borrmann type 4 in three cases, and EGC-mimicking lesion in one case. Using axial CT scan alone, Borrmann's classification based tumor morphology were accurately identified in 67.3% of cases, but using 3D imaging, the corresponding figure was 85.7%. In 33 cases receiving surgery, good correlation between axial CT scan and pathology occurred in 72.7% of T class, and 69.7% of N class. Among 21 cases of EGC, excellent 3D images were obtained in three patients (14.3%), good 3D images in 14 (66.7%), and poor 3D images in two (9.5%). The other two cases of EGC were not detected. By axial CT scan, no tumor was detected in four cases, and there were two doubtful cases. 3D images of three benign ulcers were excellent in one case and good in two. 3D images of three leiomyomas and one lymphoma were excellent. Combined axial CT imaging and 3D imaging by spiral CT has the potential to accurately diagnose gastric lesions other than AGC

Three-dimentional imaging of dentomaxillofacial region using electron beam tomography

International Nuclear Information System (INIS)

Tanaka, Takemasa; Kanda, Shigenobu; Muranaka, Toru

1998-01-01

Authors reported their results of the 3-D imaging of dentomaxillofacial region mainly for jaw deformity with electron beam tomography (EBT). The EBT apparatus used was Imatron C-100 (Imatron Corp.), with which, using bremsstrahlung radiation generated from the electron beam, CT is possible with rapid scanning rate at <0.1 sec. Imaging was done with those conditions as tube voltage: 130 kV, current: 610 mA, scanning rate: 0.1 sec/slice whose thickness was 1.5 mm, feeding rate: 1.5 mm and number of slices: 40-170. Patients were 15 cases with jaw deformity. Data were processed for 3-D image by Scribe Imaging Workstation (Multi-dimensional Imaging Inc.) which giving surface rendering and further by Power Macintosh 8500 (Apple Computer Inc.) with VoxBlast 1.1.0 (VayTec Inc.) software which giving volume rendering or with Image 1.60 (NIH) which allowing multi-planar reconstruction and re-analog projection. These actual images were presented in the report. (K.H.)

Algorithms of CT value correction for reconstructing a radiotherapy simulation image through axial CT images

International Nuclear Information System (INIS)

Ogino, Takashi; Egawa, Sunao

1991-01-01

New algorithms of CT value correction for reconstructing a radiotherapy simulation image through axial CT images were developed. One, designated plane weighting method, is to correct CT value in proportion to the position of the beam element passing through the voxel. The other, designated solid weighting method, is to correct CT value in proportion to the length of the beam element passing through the voxel and the volume of voxel. Phantom experiments showed fair spatial resolution in the transverse direction. In the longitudinal direction, however, spatial resolution of under slice thickness could not be obtained. Contrast resolution was equivalent for both methods. In patient studies, the reconstructed radiotherapy simulation image was almost similar in visual perception of the density resolution to a simulation film taken by X-ray simulator. (author)

The significance of multi-slice helical CT multiplanar reconstruction in the diagnoses of laryngeal carcinoma

International Nuclear Information System (INIS)

Li Lin; Luo Dehong; Zhou Chunwu; Zhao Xinming; Jiang Liming; Huang Yao; Jiang Lingxia; Li Jing; Wu Ning

2006-01-01

Objective: To evaluate the significance of multi-slice helical CT with multiplanar reconstruction in laryngeal carcinoma. Methods: Thirty-five patients with laryngeal carcinoma were studied by helical CT, MPR were subsequently done. The lesion extent of the axial image findings, MPR findings and the combined image findings were compared with the pathological results respectively. The data were statistically analyzed. Results: In the evaluation of the anterior commissure, the axial image findings, MPR findings and the combined image findings were 82.9%, 68.6% and 91.4% in accuracy respectively, the results were statistically different (P 0.05). The combined images were superior to the axial images and the MPR images in sensitivity, specificity and accuracy of the lesion extent. Conclusion: The axial images could show the shape, size, extension of the tumor and the lymphadenopathy, MPR images displayed the shape, size and extension roundly and directly, they were the supplement for the axial images. Axial images combined with MPR could improve the accuracy in the diagnoses of laryngeal carcinoma. (authors)

Development of an automated extraction method for liver tumors in three dimensional multiphase multislice CT images

International Nuclear Information System (INIS)

Nakagawa, Junya; Shimizu, Akinobu; Kobatake, Hidefumi

2004-01-01

This paper proposes a tumor detection method using four phase three dimensional (3D) CT images of livers, i.e. non-contrast, early, portal, and late phase images. The method extracts liver regions from the four phase images and enhances tumors in the livers using a 3D adaptive convergence index filter. Then it detects local maximum points and extracts tumor candidates by a region growing method. Subsequently several features of the candidates are measured and each candidate is classified into true tumor or normal tissue based on Mahalanobis distances. Above processes except liver region extraction are applied to four phase images, independently and four resultant images are integrated into one. We applied the proposed method to 3D abdominal CT images of ten patients obtained with multi-detector row CT scanner and confirmed that tumor detection rate was 100% without false positives, which was quite promising results. (author)

Dynamic Neuromuscular Control of the Lower Limbs in Response to Unexpected Single-Planar versus Multi-Planar Support Perturbations in Young, Active Adults.

Science.gov (United States)

Malfait, Bart; Staes, Filip; de Vries, Aijse; Smeets, Annemie; Hawken, Malcolm; Robinson, Mark A; Vanrenterghem, Jos; Verschueren, Sabine

2015-01-01

An anterior cruciate ligament (ACL) injury involves a multi-planar injury mechanism. Nevertheless, unexpected multi-planar perturbations have not been used to screen athletes in the context of ACL injury prevention yet could reveal those more at risk. The objective of this study was to compare neuromuscular responses to multi-planar (MPP) and single-planar perturbations (SPP) during a stepping-down task. These results might serve as a basis for future implementation of external perturbations in ACL injury screening programs. Thirteen young adults performed a single leg stepping-down task in eight conditions (four MPP and four SPP with a specified amplitude and velocity). The amplitudes of vastus lateralis (VL), vastus medialis (VM), hamstrings lateralis (HL), hamstrings medialis (HM) EMG activity, medio-lateral and anterior-posterior centre of mass (COM) displacements, the peak knee flexion and abduction angles were compared between conditions using an one-way ANOVA. Number of stepping responses were monitored during all conditions. Significantly greater muscle activity levels were found in response to the more challenging MPP and SPP compared to the less challenging conditions (p neuromuscular activity were found between the MPP conditions and their equivalents in the SPP. Eighteen stepping responses were monitored in the SPP versus nine in the MPP indicating that the overall neuromuscular control was even more challenged during the SPP which was supported by greater COM displacements in the SPP. The more intense MPP and SPP evoked different neuromuscular responses resulting in greater muscle activity levels compared to small perturbations. Based on the results of COM displacements and based on the amount of stepping responses, dynamic neuromuscular control of the knee joint appeared less challenged during the MPP. Therefore, future work should investigate extensively if other neuromuscular differences (i.e. co-activation patterns and kinetics) exist between MPP

Material Discriminated X-Ray CT System by Using New X-Ray Imager with Energy Discriminate Function

Directory of Open Access Journals (Sweden)

Toru Aoki

2008-04-01

Full Text Available Material discriminated X-ray CT system has been constructed by using conventional X-ray tube (white X-ray source and photon-counting X-ray imager as an application with energy band detection. We have already reported material identify X-ray CT using K-shell edge method elsewhere. In this report the principle of material discrimination was adapted the separation of electron-density and atomic number from attenuation coefficient mapping in X-ray CT reconstructed image in two wavelength X-ray CT method using white X-ray source and energy discriminated X-ray imager by using two monochrome X-ray source method. The measurement phantom was prepared as four kinds material rods (Carbon(C, Iron(Fe, Copper(Cu, Titanium(Ti rods of 3mm-diameter inside an aluminum(Al rod of 20mm-diameter. We could observed material discriminated X-ray CT reconstructed image, however, the discrimination properties were not good than two monochrome X-ray CT method. This results was could be explained because X-ray scattering, beam-hardening and so on based on white X-ray source, which could not observe in two monochrome X-ray CT method. However, since our developed CdTe imager can be detect five energy-bands at the same time, we can use multi-band analysis to decrease the least square error margin. We will be able to obtain more high separation in atomic number mapping in X-ray CT reconstructed image by using this system.

Linked statistical shape models for multi-modal segmentation: application to prostate CT-MR segmentation in radiotherapy planning

Science.gov (United States)

Chowdhury, Najeeb; Chappelow, Jonathan; Toth, Robert; Kim, Sung; Hahn, Stephen; Vapiwala, Neha; Lin, Haibo; Both, Stefan; Madabhushi, Anant

2011-03-01

We present a novel framework for building a linked statistical shape model (LSSM), a statistical shape model (SSM) that links the shape variation of a structure of interest (SOI) across multiple imaging modalities. This framework is particularly relevant in scenarios where accurate delineations of a SOI's boundary on one of the modalities may not be readily available, or difficult to obtain, for training a SSM. We apply the LSSM in the context of multi-modal prostate segmentation for radiotherapy planning, where we segment the prostate on MRI and CT simultaneously. Prostate capsule segmentation is a critical step in prostate radiotherapy planning, where dose plans have to be formulated on CT. Since accurate delineations of the prostate boundary are very difficult to obtain on CT, pre-treatment MRI is now beginning to be acquired at several medical centers. Delineation of the prostate on MRI is acknowledged as being significantly simpler to do compared to CT. Hence, our framework incorporates multi-modal registration of MRI and CT to map 2D boundary delineations of prostate (obtained from an expert radiation oncologist) on MR training images onto corresponding CT images. The delineations of the prostate capsule on MRI and CT allows for 3D reconstruction of the prostate shape which facilitates the building of the LSSM. We acquired 7 MRI-CT patient studies and used the leave-one-out strategy to train and evaluate our LSSM (fLSSM), built using expert ground truth delineations on MRI and MRI-CT fusion derived capsule delineations on CT. A unique attribute of our fLSSM is that it does not require expert delineations of the capsule on CT. In order to perform prostate MRI segmentation using the fLSSM, we employed a regionbased approach where we deformed the evolving prostate boundary to optimize a mutual information based cost criterion, which took into account region-based intensity statistics of the image being segmented. The final prostate segmentation was then

Neutron CT with a multi-detector system leading to drastical reduction of the measuring time

International Nuclear Information System (INIS)

Hehn, G.; Pfister, G.; Schatz, A.; Goebel, J.; Kofler, R.

1993-09-01

By means of numerical simulation methods and their verification with measurements it could be shown that such a detector system can be realized for a line beam and 1-2 detectors per cm. With the maximum available beam width of the fast neutron field at the FRM approximately 20 detectors can be used leading to a reduction of the measuring time to 0,5 - 1 hour. A multi detector system for a line beam of thermal neutrons was constructed, tested and used for CT-measurements. This detector system for the measurement of thinner layers with better spatial resolution could be realized. The electronic discrimination between neutrons and gamma rays has been improved. This discrimination was used in all CT-measurements to get transmission values of both kinds of radiation and to reconstruct to complementary CT-images. The use of a polyenergetic radiation causes spectral shifts in the transmission spectrum leading to artifacts in the reconstructed CT-image. The transmission values must be spectral corrected before image reconstruction, because the image artifacts complicate the image evaluation or make it impossible. A new energy selective procedure for the online spectral correction was developed. This method is based on the concept to measure additionally to the integral transmission value his pulse height spectrum and to do the correction depending on the changes in this pulse height spectrum. (orig./HP) [de

Ultrasound and PET-CT image fusion for prostate brachytherapy image guidance

International Nuclear Information System (INIS)

Hasford, F.

2015-01-01

Fusion of medical images between different cross-sectional modalities is widely used, mostly where functional images are fused with anatomical data. Ultrasound has for some time now been the standard imaging technique used for treatment planning of prostate cancer cases. While this approach is laudable and has yielded some positive results, latest developments have been the integration of images from ultrasound and other modalities such as PET-CT to compliment missing properties of ultrasound images. This study has sought to enhance diagnosis and treatment of prostate cancers by developing MATLAB algorithms to fuse ultrasound and PET-CT images. The fused ultrasound-PET-CT image has shown to contain improved quality of information than the individual input images. The fused image has the property of reduced uncertainty, increased reliability, robust system performance, and compact representation of information. The objective of co-registering the ultrasound and PET-CT images was achieved by conducting performance evaluation of the ultrasound and PET-CT imaging systems, developing image contrast enhancement algorithm, developing MATLAB image fusion algorithm, and assessing accuracy of the fusion algorithm. Performance evaluation of the ultrasound brachytherapy system produced satisfactory results in accordance with set tolerances as recommended by AAPM TG 128. Using an ultrasound brachytherapy quality assurance phantom, average axial distance measurement of 10.11 ± 0.11 mm was estimated. Average lateral distance measurements of 10.08 ± 0.07 mm, 20.01 ± 0.06 mm, 29.89 ± 0.03 mm and 39.84 ± 0.37 mm were estimated for the inter-target distances corresponding to 10 mm, 20 mm, 30 mm and 40 mm respectively. Volume accuracy assessment produced measurements of 3.97 cm 3 , 8.86 cm 3 and 20.11 cm 3 for known standard volumes of 4 cm 3 , 9 cm 3 and 20 cm 3 respectively. Depth of penetration assessment of the ultrasound system produced an estimate of 5.37 ± 0.02 cm

Comparison of planar images and SPECT with bayesean preprocessing for the demonstration of facial anatomy and craniomandibular disorders

International Nuclear Information System (INIS)

Kircos, L.T.; Ortendahl, D.A.; Hattner, R.S.; Faulkner, D.; Taylor, R.L.

1984-01-01

Craniomandiublar disorders involving the facial anatomy may be difficult to demonstrate in planar images. Although bone scanning is generally more sensitive than radiography, facial bone anatomy is complex and focal areas of increased or decreased radiotracer may become obscured by overlapping structures in planar images. Thus SPECT appears ideally suited to examination of the facial skeleton. A series of patients with craniomandibular disorders of unknown origin were imaged using 20 mCi Tc-99m MDP. Planar and SPECT (Siemens 7500 ZLC Orbiter) images were obtained four hours after injection. The SPECT images were reconstructed with a filtered back-projection algorithm. In order to improve image contrast and resolution in SPECT images, the rotation views were pre-processed with a Bayesean deblurring algorithm which has previously been show to offer improved contrast and resolution in planar images. SPECT images using the pre-processed rotation views were obtained and compared to the SPECT images without pre-processing and the planar images. TMJ arthropathy involving either the glenoid fossa or the mandibular condyle, orthopedic changes involving the mandible or maxilla, localized dental pathosis, as well as changes in structures peripheral to the facial skeleton were identified. Bayesean pre-processed SPECT depicted the facial skeleton more clearly as well as providing a more obvious demonstration of the bony changes associated with craniomandibular disorders than either planar images or SPECT without pre-processing

Multi-channel data acquisition system for CT

International Nuclear Information System (INIS)

Cao Fuqiang; He Bin; Liu Guohua; Xu Minjian

2009-01-01

The architecture design and realization of a data acquisition system for multi-channel CT is described. The article introduces the conversion of analog signal to digital signal, the data cache and transmission. This data acquisition system can be widely used in the system which requires the multi-channel, weak current signal detection. (authors)

Imaging and PET - PET/CT imaging

International Nuclear Information System (INIS)

Von Schulthess, G.K.; Hany, Th.F.

2008-01-01

PET/CT has grown because the lack of anatomic landmarks in PET makes 'hardware-fusion' to anatomic cross-sectional data extremely useful. Addition of CT to PET improves specificity, but also sensitivity, and adding PET to CT adds sensitivity and specificity in tumor imaging. The synergistic advantage of adding CT is that the attenuation correction needed for PET data can also be derived from the CT data. This makes PET-CT 25-30% faster than PET alone, leading to higher patient throughput and a more comfortable examination for patients typically lasting 20 minutes or less. FDG-PET-CT appears to provide relevant information in the staging and therapy monitoring of many tumors, such as lung carcinoma, colorectal cancer, lymphoma, gynaecological cancers, melanoma and many others, with the notable exception of prostatic cancer. for this cancer, choline derivatives may possibly become useful radiopharmaceuticals. The published literature on the applications of FDG-PET-CT in oncology is still limited but several designed studies have demonstrated the benefits of PET-CT. (authors)

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

Science.gov (United States)

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

2009-07-01

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

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

International Nuclear Information System (INIS)

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

2009-01-01

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

Improving image quality in portal venography with spectral CT imaging

International Nuclear Information System (INIS)

Zhao, Li-qin; He, Wen; Li, Jian-ying; Chen, Jiang-hong; Wang, Ke-yang; Tan, Li

2012-01-01

Objective: To investigate the effect of energy spectral CT on the image quality of CT portal venography in cirrhosis patients. Materials and methods: 30 portal hypertension patients underwent spectral CT examination using a single-tube, fast dual tube voltage switching technique. 101 sets of monochromatic images were generated from 40 keV to 140 keV. Image noise and contrast-to-noise ratio (CNR) for portal veins from the monochromatic images were measured. An optimal monochromatic image set was selected for obtaining the best CNR for portal veins. The image noise and CNR of the intra-hepatic portal vein and extra-hepatic main stem at the selected monochromatic level were compared with those from the conventional polychromatic images. Image quality was also assessed and compared. Results: The monochromatic images at 51 keV were found to provide the best CNR for both the intra-hepatic and extra-hepatic portal veins. At this energy level, the monochromatic images had about 100% higher CNR than the polychromatic images with a moderate 30% noise increase. The qualitative image quality assessment was also statistically higher with monochromatic images at 51 keV. Conclusion: Monochromatic images at 51 keV for CT portal venography could improve CNR for displaying hepatic portal veins and improve the overall image quality.

Improving image quality in portal venography with spectral CT imaging

Energy Technology Data Exchange (ETDEWEB)

Zhao, Li-qin, E-mail: zhaolqzr@sohu.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); He, Wen, E-mail: hewen1724@sina.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); Li, Jian-ying, E-mail: jianying.li@med.ge.com [CT Advanced Application and Research, GE Healthcare, 100176 China (China); Chen, Jiang-hong, E-mail: chenjianghong1973@hotmail.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); Wang, Ke-yang, E-mail: ke7ke@sina.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); Tan, Li, E-mail: Litan@ge.com [CT product, GE Healthcare, 100176 China (China)

2012-08-15

Objective: To investigate the effect of energy spectral CT on the image quality of CT portal venography in cirrhosis patients. Materials and methods: 30 portal hypertension patients underwent spectral CT examination using a single-tube, fast dual tube voltage switching technique. 101 sets of monochromatic images were generated from 40 keV to 140 keV. Image noise and contrast-to-noise ratio (CNR) for portal veins from the monochromatic images were measured. An optimal monochromatic image set was selected for obtaining the best CNR for portal veins. The image noise and CNR of the intra-hepatic portal vein and extra-hepatic main stem at the selected monochromatic level were compared with those from the conventional polychromatic images. Image quality was also assessed and compared. Results: The monochromatic images at 51 keV were found to provide the best CNR for both the intra-hepatic and extra-hepatic portal veins. At this energy level, the monochromatic images had about 100% higher CNR than the polychromatic images with a moderate 30% noise increase. The qualitative image quality assessment was also statistically higher with monochromatic images at 51 keV. Conclusion: Monochromatic images at 51 keV for CT portal venography could improve CNR for displaying hepatic portal veins and improve the overall image quality.

Detection of low-grade prosthetic joint infections using 99mTc-antigranulocyte SPECT/CT: initial clinical results

International Nuclear Information System (INIS)

Graute, Vera; Lehner, Sebastian; Haug, Alexander; Bartenstein, Peter; Hacker, Marcus; Feist, Markus; Mueller, Peter Ernst

2010-01-01

Low-grade joint infections are characterized by infiltration of granulocytes, which mediate aspects of inflammatory changes. We evaluated retrospectively the contribution of SPECT/CT as an addition to planar scintigraphy with 99m Tc-labelled antigranulocyte antibodies for diagnosing and localizing low-grade joint infections. Planar scintigraphy using 99m Tc-labelled antigranulocyte BW 250/183 antibodies was performed in 31 patients with suspected joint infections at 5 min, 5 h and 24 h after injection, with additional SPECT/CT performed 6 h after injection. With reference to gold standard clinical data, we assessed the diagnostic sensitivity of scintigraphy alone and in conjunction with SPECT/CT. Joint infections were diagnosed clinically in 9 of the 31 patients (1 hip and 8 knee prostheses). Planar scintigraphy revealed 6 true-positives, 13 true-negatives, 9 false-positives and 3 false-negative results, indicating sensitivity, specificity, positive and negative predictive values of, respectively, 0.66, 0.60, 0.4 and 0.81. With the addition of SPECT images, corresponding sensitivity, specificity, positive and negative predictive values increased to 0.89, 0.45, 0.40 and 0.91. Implementation of fused SPECT/CT led to a further increase to 0.89, 0.73, 0.57 and 0.94. Relative to planar scintigraphy, SPECT with and without CT substantially improved the utility of imaging with 99m Tc-labelled antigranulocyte antibodies for diagnosis and localization of suspected joint infections. Optimal accuracy was obtained through image fusion, which permitted anatomical allocation of foci of pathological tracer accumulation as well as providing information on the extent of the infection. This imaging method seems suited for selection of patients requiring surgical therapy. (orig.)

Evaluation of TSE- and T1-3D-GRE-sequences for focal cartilage lesions in vitro in comparison to ultrahigh resolution multi-slice CT

International Nuclear Information System (INIS)

Stork, A.; Schulze, D.; Koops, A.; Kemper, J.; Adam, G.

2002-01-01

Purpose: Evaluation of TSE- and T 1 -3D-GRE-sequences for focal cartilage lesions in vitro in comparison to ultrahigh resolution multi-slice CT. Materials and methods: Forty artificial cartilage lesions in ten bovine patellae were immersed in a solution of iodinated contrast medium and assessed with ultrahigh resolution multi-slice CT. Fat-suppressed TSE images with intermediate- and T 2 -weighting at a slice thickness of 2, 3 and 4 mm as well as fat-suppressed T 1 -weighted 3D-FLASH images with an effective slice thickness of 1, 2 and 3 mm were acquired at 1.5 T. After adding Gd-DTPA to the saline solution containing the patellae, the T 1 -weighted 3D-FLASH imaging was repeated. Results: All cartilage lesions were visualised and graded with ultrahigh resolution multi-slice CT. The TSE images had a higher sensitivity and a higher inter- and intraobserver kappa compared to the FLASH-sequences (TSE: 70-95%; 0.82-0.83; 0.85-0.9; FLASH: 57.5-85%; 0.53-0.72; 0.73-0.82, respectively). An increase in slice thickness decreased the sensitivity, whereby deep lesions were even reliably depicted on TSE images at a slice thickness of 3 and 4 mm. Adding Gd-DTPA to the saline solution increased the sensitivity by 10% with no detectable advantage over the T 2 -weighted TSE images. Conclusion: TSE sequences and application of Gd-DTPA seemed to be superior to T 1 -weighted 3D-FLASH sequences without Gd-DTPA in the detection of focal cartilage lesions. The ultrahigh resolution multi-slice CT can serve as in vitro reference standard for focal cartilage lesions. (orig.) [de

CT-MR image data fusion for computer assisted navigated neurosurgery of temporal bone tumors

International Nuclear Information System (INIS)

Nemec, Stefan Franz; Donat, Markus Alexander; Mehrain, Sheida; Friedrich, Klaus; Krestan, Christian; Matula, Christian; Imhof, Herwig; Czerny, Christian

2007-01-01

Purpose: To demonstrate the value of multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative work up of temporal bone tumors and to present, especially, CT and MR image fusion for surgical planning and performance in computer assisted navigated neurosurgery of temporal bone tumors. Materials and methods: Fifteen patients with temporal bone tumors underwent MDCT and MRI. MDCT was performed in high-resolution bone window level setting in axial plane. The reconstructed MDCT slice thickness was 0.8 mm. MRI was performed in axial and coronal plane with T2-weighted fast spin-echo (FSE) sequences, un-enhanced and contrast-enhanced T1-weighted spin-echo (SE) sequences, and coronal T1-weighted SE sequences with fat suppression and with 3D T1-weighted gradient-echo (GE) contrast-enhanced sequences in axial plane. The 3D T1-weighted GE sequence had a slice thickness of 1 mm. Image data sets of CT and 3D T1-weighted GE sequences were merged utilizing a workstation to create CT-MR fusion images. MDCT and MR images were separately used to depict and characterize lesions. The fusion images were utilized for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient. Results: Tumorous lesions of bone and soft tissue were well delineated and characterized by CT and MR images. The images played a crucial role in the differentiation of benign and malignant pathologies, which consisted of 13 benign and 2 malignant tumors. The CT-MR fusion images supported the surgeon in preoperative planning and improved surgical performance. The mean intraoperative accuracy of the navigation system was 1.25 mm. Conclusion: CT and MRI are essential in the preoperative work up of temporal bone tumors. CT-MR image data fusion presents an accurate tool for planning the correct surgical procedure and is a

Nontraumatic femoral head necrosis. Classification of bone scintigraphic findings and diagnostic value of SPECT following planar imaging

Energy Technology Data Exchange (ETDEWEB)

Minoshima, Satoshi; Uchida, Yoshitaka; Anzai, Yoshimi; Uno, Kimiichi; Arimizu, Noboru [Chiba Univ. (Japan). School of Medicine

1994-09-01

This study was conducted to determine bone scintigraphic findings in nontraumatic femoral head avascular necrosis and diagnostic value of SPECT imaging following a conventional planar imaging. Forty-three femoral heads in twenty-six cases with idiopathic femoral head necrosis (n=2), systemic lupus erythematosus (n=22), aplastic anemia (n=1), and renal transplantation (n=1) were studied. The diagnosis for femoral head necrosis was based on magnetic resonance imaging as well as other diagnostic studies in all cases. Scintigraphic findings of planar and SPECT images were classified into six categories: normal (N); cold or decrease (C); partial increase with cold or decrease (PH+C); ring-like increase with a cold center (RH+C); partial increase (PH); diffuse and/or irregular increase (DH). Avascular necrosis was confirmed in twenty-four femoral heads, in which planar and SPECT images showed scintigraphic findings of N (n=3, 2), C (n=1, 3), PH+C (n=2, 8), RH+C (n=2, 3), PH (n=9, 2), and DH (n=7, 6), respectively. Femoral heads without avascular necrosis demonstrated planar and SPECT findings of N (n=16, 12), C (n=0, 6), and DH (n=3, 1), respectively. When considering C, PH+C, and RH+C as diagnostic findings for avascular necrosis, sensitivities of planar and SPECT images were 21% and 58%, and specificities were 100% and 68%, respectively. In nineteen femoral heads with normal planar findings (N), SPECT correctly identified avascular necrosis in two femoral heads and misidentified six normal femoral heads as avascular necrosis. In nineteen femoral heads with nondiagnostic abnormalities (PH, DH), SPECT correctly identified avascular necrosis in seven femoral heads and showed no false positive. Diagnostic planar findings in five femoral heads were concordant with SPECT diagnosis. These results indicate that SPECT imaging is most valuable when planar images show nondiagnostic abnormalities based on the proposed classification of scintigraphic findings. (author).

Nontraumatic femoral head necrosis. Classification of bone scintigraphic findings and diagnostic value of SPECT following planar imaging

International Nuclear Information System (INIS)

Minoshima, Satoshi; Uchida, Yoshitaka; Anzai, Yoshimi; Uno, Kimiichi; Arimizu, Noboru

1994-01-01

This study was conducted to determine bone scintigraphic findings in nontraumatic femoral head avascular necrosis and diagnostic value of SPECT imaging following a conventional planar imaging. Forty-three femoral heads in twenty-six cases with idiopathic femoral head necrosis (n=2), systemic lupus erythematosus (n=22), aplastic anemia (n=1), and renal transplantation (n=1) were studied. The diagnosis for femoral head necrosis was based on magnetic resonance imaging as well as other diagnostic studies in all cases. Scintigraphic findings of planar and SPECT images were classified into six categories: normal (N); cold or decrease (C); partial increase with cold or decrease (PH+C); ring-like increase with a cold center (RH+C); partial increase (PH); diffuse and/or irregular increase (DH). Avascular necrosis was confirmed in twenty-four femoral heads, in which planar and SPECT images showed scintigraphic findings of N (n=3, 2), C (n=1, 3), PH+C (n=2, 8), RH+C (n=2, 3), PH (n=9, 2), and DH (n=7, 6), respectively. Femoral heads without avascular necrosis demonstrated planar and SPECT findings of N (n=16, 12), C (n=0, 6), and DH (n=3, 1), respectively. When considering C, PH+C, and RH+C as diagnostic findings for avascular necrosis, sensitivities of planar and SPECT images were 21% and 58%, and specificities were 100% and 68%, respectively. In nineteen femoral heads with normal planar findings (N), SPECT correctly identified avascular necrosis in two femoral heads and misidentified six normal femoral heads as avascular necrosis. In nineteen femoral heads with nondiagnostic abnormalities (PH, DH), SPECT correctly identified avascular necrosis in seven femoral heads and showed no false positive. Diagnostic planar findings in five femoral heads were concordant with SPECT diagnosis. These results indicate that SPECT imaging is most valuable when planar images show nondiagnostic abnormalities based on the proposed classification of scintigraphic findings. (author)

The diagnostic value of multi-slice spiral CT virtual bronchoscopy in tracheal and bronchial disease

International Nuclear Information System (INIS)

Han Ying; Ma Daqing

2006-01-01

Objective: To assess the diagnostic value of multi-slice spiral CT virtual bronchoscopy (CTVB) in tracheal and bronchial disease. Methods: Forty-two patients including central lung cancer (n=35), endobronchial tuberculosis (n=3), intrabronchial benign tumor (n=3), and intrabronchial foreign body (n=1) were examined by using multi-slice spiral CT examinations. All the final diagnosis were proved by pathology except 1 patient with endoluminal foreign body was proved by clinic. All patients were scanned on GE Lightspeed 99 scanner, using 10 mm collimation, pitch of 1.35, and reconstructed at 1 mm intervals and 1.25 mm thickness. The chest images of transverse CT and virtual bronchoscopy were viewed by two separate radiologists who were familiar with the tracheal and bronchial anatomy. Results: Among the 42 patients, the tumor of trachea and bronchial lumen appeared as masses in 22 of 35 patients with central lung cancer and bronchial stenosis was found in 13 of 35 patients with central lung cancer, and bronchial wall thickening was revealed on transverse CT in all 35 cases. 3 patients of endobronchial tuberculosis showed bronchial lumen narrowing on CTVB, the bronchial wall thickening was revealed on transverse CT, and the length of the wall thickening was long. 3 patients with intrabronchial benign tumor showed nodules in trachea and bronchial lumen on CTVB, and without wall thickening on transverse CT. CTVB could detect the occlusion of bronchial lumen in 1 patient with intrabronchial foreign body and CTVB was able to visualize the areas beyond stenosis, and the bronchial wall was without thickening on transverse CT. Conclusion: Multi- slice spiral CTVB could reflect the morphology of tracheal and bronchial disease. Combined with transverse CT, it could provide diagnostic reference value for bronchial disease. (authors)

90Y microsphere therapy: does 90Y PET/CT imaging obviate the need for 90Y Bremsstrahlung SPECT/CT imaging?

Science.gov (United States)

Zade, Anand A; Rangarajan, Venkatesh; Purandare, Nilendu C; Shah, Sneha A; Agrawal, Archi R; Kulkarni, Suyash S; Shetty, Nitin

2013-11-01

Transarterial radioembolization using Y microspheres is a novel therapeutic option for inoperable hepatic malignancies. As these spheres are radiolucent, real-time assessment of their distribution during the infusion process under fluoroscopic guidance is not possible. Bremsstrahlung radiations arising from 90Y have conventionally been used for imaging its biodistribution. Recent studies have proved that sources of 90Y also emit positrons, which can further be used for PET/computed tomography (CT) imaging. This study aimed to assess the feasibility of 90Y PET/CT imaging in evaluating microsphere distributions and to compare its findings with those of Bremsstrahlung imaging. Thirty-five sessions of 90Y microsphere transarterial radioembolization were performed on 30 patients with hepatic malignancies. 90Y PET/CT imaging was performed within 3 h of therapy. Bremsstrahlung imaging was also performed for each patient. The imaging findings were compared for concordance in the distribution of microspheres. Exact one-to-one correspondence between 90Y PET/CT imaging and 90Y Bremsstrahlung imaging was observed in 97.14% of cases (i.e. in 34/35 cases). Discordance was observed only in one case in which 90Y PET/CT imaging resolved the microsphere uptake in the inferior vena cava tumor thrombus, which was, however, not visualized on Bremsstrahlung imaging. There is good concordance in the imaging findings of 90Y PET/CT and 90Y Bremsstrahlung imaging. 90Y PET/CT imaging scores over the conventionally used Bremsstrahlung imaging in terms of better resolution, ease of technique, and comparable image acquisition time. This makes it a preferred imaging modality for assessment of the distribution of 90Y microspheres.

A new technique for noise reduction at coronary CT angiography with multi-phase data-averaging and non-rigid image registration

Energy Technology Data Exchange (ETDEWEB)

Tatsugami, Fuminari; Higaki, Toru; Nakamura, Yuko; Yamagami, Takuji; Date, Shuji; Awai, Kazuo [Hiroshima University, Department of Diagnostic Radiology, Minami-ku, Hiroshima (Japan); Fujioka, Chikako; Kiguchi, Masao [Hiroshima University, Department of Radiology, Minami-ku, Hiroshima (Japan); Kihara, Yasuki [Hiroshima University, Department of Cardiovascular Medicine, Minami-ku, Hiroshima (Japan)

2015-01-15

To investigate the feasibility of a newly developed noise reduction technique at coronary CT angiography (CTA) that uses multi-phase data-averaging and non-rigid image registration. Sixty-five patients underwent coronary CTA with prospective ECG-triggering. The range of the phase window was set at 70-80 % of the R-R interval. First, three sets of consecutive volume data at 70 %, 75 % and 80 % of the R-R interval were prepared. Second, we applied non-rigid registration to align the 70 % and 80 % images to the 75 % image. Finally, we performed weighted averaging of the three images and generated a de-noised image. The image noise and contrast-to-noise ratio (CNR) in the proximal coronary arteries between the conventional 75 % and the de-noised images were compared. Two radiologists evaluated the image quality using a 5-point scale (1, poor; 5, excellent). On de-noised images, mean image noise was significantly lower than on conventional 75 % images (18.3 HU ± 2.6 vs. 23.0 HU ± 3.3, P < 0.01) and the CNR was significantly higher (P < 0.01). The mean image quality score for conventional 75 % and de-noised images was 3.9 and 4.4, respectively (P < 0.01). Our method reduces image noise and improves image quality at coronary CTA. (orig.)

Abdominal multi-organ CT segmentation using organ correlation graph and prediction-based shape and location priors.

Science.gov (United States)

Okada, Toshiyuki; Linguraru, Marius George; Hori, Masatoshi; Summers, Ronald M; Tomiyama, Noriyuki; Sato, Yoshinobu

2013-01-01

The paper addresses the automated segmentation of multiple organs in upper abdominal CT data. We propose a framework of multi-organ segmentation which is adaptable to any imaging conditions without using intensity information in manually traced training data. The features of the framework are as follows: (1) the organ correlation graph (OCG) is introduced, which encodes the spatial correlations among organs inherent in human anatomy; (2) the patient-specific organ shape and location priors obtained using OCG enable the estimation of intensity priors from only target data and optionally a number of untraced CT data of the same imaging condition as the target data. The proposed methods were evaluated through segmentation of eight abdominal organs (liver, spleen, left and right kidney, pancreas, gallbladder, aorta, and inferior vena cava) from 86 CT data obtained by four imaging conditions at two hospitals. The performance was comparable to the state-of-the-art method using intensity priors constructed from manually traced data.

PET/CT imaging in head and neck tumors

International Nuclear Information System (INIS)

Roedel, R.; Palmedo, H.; Reichmann, K.; Reinhardt, M.J.; Biersack, H.J.; Straehler-Pohl, H.J.; Jaeger, U.

2004-01-01

To evaluate the usefulness of combined PET/CT examinations for detection of malignant tumors and their metastases in head and neck oncology. 51 patients received whole body scans on a dual modality PET/CT system. CT was performed without i.v. contrast. The results were compared concerning the diagnostic impact of native CT scan on FDG-PET images and the additional value of fused imaging. From 153 lesions were 97 classified as malignant on CT and 136 on FDG/PET images, as suspicious for malignancy in 33 on CT and 7 on FDG-PET and as benign in 23 on CT and 10 on FDG-PET. With combined PET/CT all primary and recurrent tumors could be found, the detection rate in patients with unknown primary tumors was 45%. Compared to PET or CT alone the sensitivity, specifity and accuracy could be significantly improved by means of combined PET/CT. Fused PET/CT imaging with [F18]-FDG and native CT-scanning enables accurate diagnosis in 93% of lesions and 90% of patients with head and neck oncology. (orig.) [de

An attenuation correction method for PET/CT images

International Nuclear Information System (INIS)

Ue, Hidenori; Yamazaki, Tomohiro; Haneishi, Hideaki

2006-01-01

In PET/CT systems, accurate attenuation correction can be achieved by creating an attenuation map from an X-ray CT image. On the other hand, respiratory-gated PET acquisition is an effective method for avoiding motion blurring of the thoracic and abdominal organs caused by respiratory motion. In PET/CT systems employing respiratory-gated PET, using an X-ray CT image acquired during breath-holding for attenuation correction may have a large effect on the voxel values, especially in regions with substantial respiratory motion. In this report, we propose an attenuation correction method in which, as the first step, a set of respiratory-gated PET images is reconstructed without attenuation correction, as the second step, the motion of each phase PET image from the PET image in the same phase as the CT acquisition timing is estimated by the previously proposed method, as the third step, the CT image corresponding to each respiratory phase is generated from the original CT image by deformation according to the motion vector maps, and as the final step, attenuation correction using these CT images and reconstruction are performed. The effectiveness of the proposed method was evaluated using 4D-NCAT phantoms, and good stability of the voxel values near the diaphragm was observed. (author)

Two-Dimensional Image Fusion of Planar Bone Scintigraphy and Radiographs in Patients with Clinical Scaphoid Fracture: An Imaging Study

DEFF Research Database (Denmark)

Henriksen, O.M.; Lonsdale, M.N.; Jensen, T.D.

2008-01-01

. Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy. Purpose: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation......Background: Although magnetic resonance imaging (MRI) is now considered the gold standard in second-line imaging of patients with suspected scaphoid fracture and negative radiographs, bone scintigraphy can be used in patients with pacemakers, metallic implants, or other contraindications to MRI....... Conclusion: Image fusion of planar bone scintigrams and radiographs has a significant influence on image interpretation and increases both diagnostic confidence and interobserver agreement Udgivelsesdato: 2008/12/3...

Two-dimensional fusion imaging of planar bone scintigraphy and radiographs in patients with clinical scaphoid fracture: an imaging study

DEFF Research Database (Denmark)

Henriksen, Otto Mølby; Lonsdale, Markus Georg; Jensen, T D

2009-01-01

. Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy. PURPOSE: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation......BACKGROUND: Although magnetic resonance imaging (MRI) is now considered the gold standard in second-line imaging of patients with suspected scaphoid fracture and negative radiographs, bone scintigraphy can be used in patients with pacemakers, metallic implants, or other contraindications to MRI....... CONCLUSION: Image fusion of planar bone scintigrams and radiographs has a significant influence on image interpretation and increases both diagnostic confidence and interobserver agreement....

Co-registered perfusion SPECT/CT: Utility for prediction of improved postoperative outcome in lung volume reduction surgery candidates

International Nuclear Information System (INIS)

Takenaka, Daisuke; Ohno, Yoshiharu; Koyama, Hisanobu; Nogami, Munenobu; Onishi, Yumiko; Matsumoto, Keiko; Yoshikawa, Takeshi; Matsumoto, Sumiaki; Sugimura, Kazuro

2010-01-01

Purpose: To directly compare the capabilities of perfusion scan, SPECT, co-registered SPECT/CT, and quantitatively and qualitatively assessed MDCT (i.e. quantitative CT and qualitative CT) for predicting postoperative clinical outcome for lung volume reduction surgery (LVRS) candidates. Materials and methods: Twenty-five consecutive candidates (19 men and six women, age range: 42-72 years) for LVRS underwent preoperative CT and perfusion scan with SPECT. Clinical outcome of LVRS for all subjects was also assessed by determining the difference between pre- and postoperative forced expiratory volume in 1 s (FEV 1 ) and 6-min walking distance (6MWD). All SPECT examinations were performed on a SPECT scanner, and co-registered to thin-section CT by using commercially available software. On planar imaging, SPECT and SPECT/CT, upper versus lower zone or lobe ratios (U/Ls) were calculated from regional uptakes between upper and lower lung fields in the operated lung. On quantitatively assessed CT, U/L for all subjects was assessed from regional functional lung volumes. On qualitatively assessed CT, planar imaging, SPECT and co-registered SPECT/CT, U/Ls were assessed with a 4-point visual scoring system. To compare capabilities of predicting clinical outcome, each U/L was statistically correlated with the corresponding clinical outcome. Results: Significantly fair or moderate correlations were observed between quantitatively and qualitatively assessed U/Ls obtained with all four methods and clinical outcomes (-0.60 ≤ r ≤ -0.42, p < 0.05). Conclusion: Co-registered perfusion SPECT/CT has better correlation with clinical outcome in LVRS candidates than do planar imaging, SPECT or qualitatively assessed CT, and is at least as valid as quantitatively assessed CT.

Co-registered perfusion SPECT/CT: Utility for prediction of improved postoperative outcome in lung volume reduction surgery candidates

Energy Technology Data Exchange (ETDEWEB)

Takenaka, Daisuke [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.j [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017 (Japan); Koyama, Hisanobu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017 (Japan); Nogami, Munenobu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017 (Japan); Division of Image-Based Medicine, Institute of Biomedical Research and Innovation, 2-2, Minatojima Minamimachi Chuo-ku, Kobe, Hyogo, 650-0047 (Japan); Onishi, Yumiko [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017 (Japan); Matsumoto, Keiko [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017 (Japan); Department of Radiology, University of Yamanashi, 1110 Shimogato, Chuo, Yamanashi, 409-3898 (Japan); Yoshikawa, Takeshi; Matsumoto, Sumiaki; Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017 (Japan)

2010-06-15

Purpose: To directly compare the capabilities of perfusion scan, SPECT, co-registered SPECT/CT, and quantitatively and qualitatively assessed MDCT (i.e. quantitative CT and qualitative CT) for predicting postoperative clinical outcome for lung volume reduction surgery (LVRS) candidates. Materials and methods: Twenty-five consecutive candidates (19 men and six women, age range: 42-72 years) for LVRS underwent preoperative CT and perfusion scan with SPECT. Clinical outcome of LVRS for all subjects was also assessed by determining the difference between pre- and postoperative forced expiratory volume in 1 s (FEV{sub 1}) and 6-min walking distance (6MWD). All SPECT examinations were performed on a SPECT scanner, and co-registered to thin-section CT by using commercially available software. On planar imaging, SPECT and SPECT/CT, upper versus lower zone or lobe ratios (U/Ls) were calculated from regional uptakes between upper and lower lung fields in the operated lung. On quantitatively assessed CT, U/L for all subjects was assessed from regional functional lung volumes. On qualitatively assessed CT, planar imaging, SPECT and co-registered SPECT/CT, U/Ls were assessed with a 4-point visual scoring system. To compare capabilities of predicting clinical outcome, each U/L was statistically correlated with the corresponding clinical outcome. Results: Significantly fair or moderate correlations were observed between quantitatively and qualitatively assessed U/Ls obtained with all four methods and clinical outcomes (-0.60 {<=} r {<=} -0.42, p < 0.05). Conclusion: Co-registered perfusion SPECT/CT has better correlation with clinical outcome in LVRS candidates than do planar imaging, SPECT or qualitatively assessed CT, and is at least as valid as quantitatively assessed CT.

Dual source CT imaging

International Nuclear Information System (INIS)

Seidensticker, Peter R.; Hofmann, Lars K.

2008-01-01

The introduction of Dual Source Computed Tomography (DSCT) in 2005 was an evolutionary leap in the field of CT imaging. Two x-ray sources operated simultaneously enable heart-rate independent temporal resolution and routine spiral dual energy imaging. The precise delivery of contrast media is a critical part of the contrast-enhanced CT procedure. This book provides an introduction to DSCT technology and to the basics of contrast media administration followed by 25 in-depth clinical scan and contrast media injection protocols. All were developed in consensus by selected physicians on the Dual Source CT Expert Panel. Each protocol is complemented by individual considerations, tricks and pitfalls, and by clinical examples from several of the world's best radiologists and cardiologists. This extensive CME-accredited manual is intended to help readers to achieve consistently high image quality, optimal patient care, and a solid starting point for the development of their own unique protocols. (orig.)

Readout-Segmented Echo-Planar Imaging in Diffusion-Weighted MR Imaging in Breast Cancer: Comparison with Single-Shot Echo-Planar Imaging in Image Quality

International Nuclear Information System (INIS)

Kim, Yun Ju; Kim, Sung Hun; Kang, Bong Joo; Park, Chang Suk; Kim, Hyeon Sook; Son, Yo Han; Porter, David Andrew; Song, Byung Joo

2014-01-01

The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer. Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated. The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR. Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast

Towards truly integrated hardware fusion with PET/CT

International Nuclear Information System (INIS)

Beyer, T.

2005-01-01

Combined PET/CT imaging is a non-invasive means of acquiring and reviewing both, the anatomy and the molecular pathways of a patient during a quasi-simultaneous examination. Since the introduction of the prototype PET/CT in 1998 this imaging technology has evolved rapidly. State-of-the-art PET/CT tomographs combine the latest technology in spiral, multi-slice CT and PET using novel scintillator materials and image reconstruction techniques. Together with novel patient positioning systems PET/CT tomographs allow to acquire complementary PET and CT data in a single exam with the best intrinsic co-registration. In addition to the hardware integration efforts have been made to integrate the acquisition and viewing software in PET/CT, thus making the diagnostic review and reporting more efficient. Based on the first clinical experiences and the technical evolution of combined imaging technology PET/CT has become a standard in diagnostic oncology. With high-performance imaging technology at hand today, standardized, high-quality PET/CT imaging protocols are needed to provide best oncology patient care. These protocols mandate the joint efforts of a multi-disciplinary team of physicians, physicists and radiochemists. (orig.)

The added value of SPECT-CT for the identification of sentinel lymph nodes in early stage oral cancer

International Nuclear Information System (INIS)

Toom, Inne J. den; Bree, Remco de; Schie, Annelies van; Hoekstra, Otto S.; Weert, Stijn van; Karagozoglu, K.H.; Bloemena, Elisabeth

2017-01-01

To assess the role of single-photon emission computed tomography with computed tomography (SPECT-CT) for the identification of sentinel lymph nodes (SLNs) in patients with early stage (T1-T2) oral cancer and a clinically negative neck (cN0). In addition to planar lymphoscintigraphy, SPECT-CT was performed in 66 consecutive patients with early stage oral cancer and a clinically negative neck. The addition of SPECT-CT to planar images was retrospectively analyzed for the number of additional SLNs, more precise localization of SLNs, and importance of anatomical information by a team consisting of a nuclear physician, surgeon, and investigator. Identification rate for both imaging modalities combined was 98% (65/66). SPECT-CT identified 15 additional SLNs in 14 patients (22%). In 2/15 (13%) of these additional SLNs, the only metastasis was found, resulting in an upstaging rate of 3% (2/65). In 20% of the patients with at least one positive SLN, the only positive SLN was detected due to the addition of SPECT-CT. SPECT-CT was considered to add important anatomical information in two patients (3%). In 5/65 (8%) of the patients initially scored SLNs on planar lymphoscintigrams were scored as non-SLNs when SPECT-CT was added. There were four false-negative SLN biopsy procedures in this cohort. The addition of SPECT-CT to planar lymphoscintigraphy is recommended for the identification of more (positive) SLNs and better topographical orientation for surgery in sentinel lymph node biopsy for early stage oral cancer. (orig.)

The added value of SPECT-CT for the identification of sentinel lymph nodes in early stage oral cancer

Energy Technology Data Exchange (ETDEWEB)

Toom, Inne J. den; Bree, Remco de [VU University Medical Center, Department of Otolaryngology-Head and Neck Surgery, Amsterdam (Netherlands); UMC Utrecht Cancer Center, University Medical Center, Department of Head and Neck Surgical Oncology, PO Box 85500, Utrecht (Netherlands); Schie, Annelies van; Hoekstra, Otto S. [VU University Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Weert, Stijn van [VU University Medical Center, Department of Otolaryngology-Head and Neck Surgery, Amsterdam (Netherlands); Karagozoglu, K.H. [VU University Medical Center/Academic Centre for Dentistry (ACTA) Amsterdam, Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam (Netherlands); Bloemena, Elisabeth [VU University Medical Center/Academic Centre for Dentistry (ACTA) Amsterdam, Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam (Netherlands); VU University Medical Center, Department of Pathology, Amsterdam (Netherlands)

2017-06-15

To assess the role of single-photon emission computed tomography with computed tomography (SPECT-CT) for the identification of sentinel lymph nodes (SLNs) in patients with early stage (T1-T2) oral cancer and a clinically negative neck (cN0). In addition to planar lymphoscintigraphy, SPECT-CT was performed in 66 consecutive patients with early stage oral cancer and a clinically negative neck. The addition of SPECT-CT to planar images was retrospectively analyzed for the number of additional SLNs, more precise localization of SLNs, and importance of anatomical information by a team consisting of a nuclear physician, surgeon, and investigator. Identification rate for both imaging modalities combined was 98% (65/66). SPECT-CT identified 15 additional SLNs in 14 patients (22%). In 2/15 (13%) of these additional SLNs, the only metastasis was found, resulting in an upstaging rate of 3% (2/65). In 20% of the patients with at least one positive SLN, the only positive SLN was detected due to the addition of SPECT-CT. SPECT-CT was considered to add important anatomical information in two patients (3%). In 5/65 (8%) of the patients initially scored SLNs on planar lymphoscintigrams were scored as non-SLNs when SPECT-CT was added. There were four false-negative SLN biopsy procedures in this cohort. The addition of SPECT-CT to planar lymphoscintigraphy is recommended for the identification of more (positive) SLNs and better topographical orientation for surgery in sentinel lymph node biopsy for early stage oral cancer. (orig.)

PET/CT. Dose-escalated image fusion?

International Nuclear Information System (INIS)

Brix, G.; Beyer, T.

2005-01-01

Clinical studies demonstrate a gain in diagnostic accuracy by employing combined PET/CT instead of separate CT and PET imaging. However, whole-body PET/CT examinations result in a comparatively high radiation burden to patients and thus require a proper justification and optimization to avoid repeated exposure or over-exposure of patients. This review article summarizes relevant data concerning radiation exposure of patients resulting from the different components of a combined PET/CT examination and presents different imaging strategies that can help to balance the diagnostic needs and the radiation protection requirements. In addition various dose reduction measures are discussed, some of which can be adopted from CT practice, while others mandate modifications to the existing hard- and software of PET/CT systems. (orig.)

Detection of low-grade prosthetic joint infections using {sup 99m}Tc-antigranulocyte SPECT/CT: initial clinical results

Energy Technology Data Exchange (ETDEWEB)

Graute, Vera; Lehner, Sebastian; Haug, Alexander; Bartenstein, Peter; Hacker, Marcus [University of Munich, Department of Nuclear Medicine, Munich (Germany); Feist, Markus; Mueller, Peter Ernst [University of Munich, Department of Orthopedic Medicine, Munich (Germany)

2010-09-15

Low-grade joint infections are characterized by infiltration of granulocytes, which mediate aspects of inflammatory changes. We evaluated retrospectively the contribution of SPECT/CT as an addition to planar scintigraphy with {sup 99m}Tc-labelled antigranulocyte antibodies for diagnosing and localizing low-grade joint infections. Planar scintigraphy using {sup 99m}Tc-labelled antigranulocyte BW 250/183 antibodies was performed in 31 patients with suspected joint infections at 5 min, 5 h and 24 h after injection, with additional SPECT/CT performed 6 h after injection. With reference to gold standard clinical data, we assessed the diagnostic sensitivity of scintigraphy alone and in conjunction with SPECT/CT. Joint infections were diagnosed clinically in 9 of the 31 patients (1 hip and 8 knee prostheses). Planar scintigraphy revealed 6 true-positives, 13 true-negatives, 9 false-positives and 3 false-negative results, indicating sensitivity, specificity, positive and negative predictive values of, respectively, 0.66, 0.60, 0.4 and 0.81. With the addition of SPECT images, corresponding sensitivity, specificity, positive and negative predictive values increased to 0.89, 0.45, 0.40 and 0.91. Implementation of fused SPECT/CT led to a further increase to 0.89, 0.73, 0.57 and 0.94. Relative to planar scintigraphy, SPECT with and without CT substantially improved the utility of imaging with {sup 99m}Tc-labelled antigranulocyte antibodies for diagnosis and localization of suspected joint infections. Optimal accuracy was obtained through image fusion, which permitted anatomical allocation of foci of pathological tracer accumulation as well as providing information on the extent of the infection. This imaging method seems suited for selection of patients requiring surgical therapy. (orig.)

Image mottle in abdominal CT.

Science.gov (United States)

Ende, J F; Huda, W; Ros, P R; Litwiller, A L

1999-04-01

To investigate image mottle in conventional CT images of the abdomen as a function of radiographic technique factors and patient size. Water-filled phantoms simulating the abdomens of adult (32 cm in diameter) and pediatric (16 cm in diameter) patients were used to investigate image mottle in CT as a function of x-ray tube potential and mAs. CT images from 39 consecutive patients with noncontrast liver scans and 49 patients with iodine contrast scans were analyzed retrospectively. Measurements were made of the mean liver parenchyma Hounsfield unit value and the corresponding image mottle. For a given water phantom and x-ray tube potential, image mottle was proportional to the mAs-0.5. Increasing the phantom diameter from 16 cm (pediatric) to 32 cm increased the mottle by a factor of 2.4, and increasing the x-ray tube potential from 80 kVp to 140 kVp reduced the mottle by a factor of 2.5. All patients were scanned at 120 kVp, with no correlation between patient size and the x-ray tube mAs. The mean mottle level was 7.8 +/- 2.2 and 10.0 +/- 2.5 for the noncontrast and contrast studies, respectively. An increase in patient diameter of 3 cm would require approximately 65% more mAs to maintain the same level of image mottle. The mottle in abdominal CT images may be controlled by adjusting radiographic technique factors, which should be adjusted to take into account the size of the patient undergoing the examination.

Dual energy CT: New horizon in medical imaging

Energy Technology Data Exchange (ETDEWEB)

Goo, Hyun Woo [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Goo, Jin Mo [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2017-08-01

Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

Dual-Energy CT: New Horizon in Medical Imaging.

Science.gov (United States)

Goo, Hyun Woo; Goo, Jin Mo

2017-01-01

Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

An approach for quantitative image quality analysis for CT

Science.gov (United States)

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

2016-03-01

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

Development of comprehensive image processing technique for differential diagnosis of liver disease by using multi-modality images. Pixel-based cross-correlation method using a profile

International Nuclear Information System (INIS)

Inoue, Akira; Okura, Yasuhiko; Akiyama, Mitoshi; Ishida, Takayuki; Kawashita, Ikuo; Ito, Katsuyoshi; Matsunaga, Naofumi; Sanada, Taizo

2009-01-01

Imaging techniques such as high magnetic field imaging and multidetector-row CT have been markedly improved recently. The final image-reading systems easily produce more than a thousand diagnostic images per patient. Therefore, we developed a comprehensive cross-correlation processing technique using multi-modality images, in order to decrease the considerable time and effort involved in the interpretation of a radiogram (multi-formatted display and/or stack display method, etc). In this scheme, the criteria of an attending radiologist for the differential diagnosis of liver cyst, hemangioma of liver, hepatocellular carcinoma, and metastatic liver cancer on magnetic resonance images with various sequences and CT images with and without contrast enhancement employ a cross-correlation coefficient. Using a one-dimensional cross-correlation method, comprehensive image processing could be also adapted for various artifacts (some depending on modality imaging, and some on patients), which may be encountered at the clinical scene. This comprehensive image-processing technique could assist radiologists in the differential diagnosis of liver diseases. (author)

Variability in DMSA reporting following urinary tract infection in children: pinhole, planar, and pinhole with planar

International Nuclear Information System (INIS)

Rossleigh, M.A.; Christian, C.L.; Craig, J.C.; Howman-Giles, R.B.; Grunewald, S.

2004-01-01

Purpose: To determine whether the provision of DMSA images obtained by pinhole collimation reduces inter-observer variability of reporting compared with planar DMSA images alone. Methods: One hundred consecutive DMSA images were independently interpreted three times (pinhole alone, planar alone, pinhole and planar) by four participating nuclear medicine specialists from different departments and in random order. The presence or absence of renal parenchymal abnormality was classified using the modified four level grading system of Goldraich with mean values for the 6 comparisons reported. Results: The proportion of DMSA images interpreted as abnormal was 31% for planar, 34% for pinhole and 33% for planar with pinhole. Agreement was 89% for planar alone, 89% for pinhole alone and 90% for planar with pinhole, with kappa values 0.74, 0.75 and 0.80 respectively for the normal-abnormal scan classification of individual children. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. Reasons for disagreement in reporting included different interpretations of 'abnormalities' as normal anatomical variations (splenic impression, fetal lobulation, duplex collecting systems, column of Bertin) or true parenchymal abnormalities, different adjustments in thresholds for reporting abnormality when images were technically suboptimal, different weighting given to pinhole and planar images when both were provided, and error. Conclusion: Four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone, pinhole alone and planar with pinhole DMSA images, but the provision of both sets of images, planar and pinhole, did not reduce variability. (authors)

Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease

International Nuclear Information System (INIS)

Hyare, Harpreet; Desigan, Sharmini; Nicholl, Helen; Guiney, Michael J.; Brookes, Jocelyn A.; Lees, William R.

2006-01-01

Purpose: Major arterial hemorrhage is an uncommon but serious complication of pancreatitis with high morbidity and mortality. Digital subtraction angiography (DSA) has long been the gold standard for the detection of a visceral artery pseudoaneurysm or for the site of active bleeding in patients with pancreatitis. Multi-section CT angiography is a minimally invasive technique which can provide high-resolution and high-contrast images of the arterial lumen and wall, with a much lower risk of complication and morbidity compared to DSA. The aim of this study was to determine the accuracy of multi-section CT angiography for the diagnosis of arterial complications of inflammatory pancreatitic disease. Materials and methods: A retrospective analysis of all patients undergoing visceral angiography for major bleeding as a complication of pancreatitis between 1998 and 2004 was performed. Twenty-nine studies in 25 patients (20 males, 5 females) with a mean age of 50.9 years (range 11-67 years) were identified where multi-section CT angiography was performed in the 24 h preceding the digital subtraction angiogram. Results: Digital subtraction angiography detected a pseudoaneurysm or contrast extravasation in 19 studies and no bleeding was demonstrated in 9 studies. CT angiography correctly identified the site and type of bleeding in 18 of the 19 positive studies. CT angiography detected extravasation of contrast in one study that was not demonstrated on digital subtraction angiography. The sensitivity and specificity for multi-section CT angiography for the detection of major arterial bleeding on a background of pancreatitis were 0.947 and 0.900, respectively. Conclusion: Multi-section CT angiography is a sensitive and accurate technique for the detection of major arterial hemorrhage in inflammatory pancreatic disease and should be considered as the first investigation in the management of these patients

Nanoscale imaging of the growth and division of bacterial cells on planar substrates with the atomic force microscope

Energy Technology Data Exchange (ETDEWEB)

Van Der Hofstadt, M. [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Hüttener, M.; Juárez, A. [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Departament de Microbiologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona (Spain); Gomila, G., E-mail: ggomila@ibecbarcelona.eu [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Departament d' Electronica, Universitat de Barcelona, C/ Marti i Franqués 1, 08028 Barcelona (Spain)

2015-07-15

With the use of the atomic force microscope (AFM), the Nanomicrobiology field has advanced drastically. Due to the complexity of imaging living bacterial processes in their natural growing environments, improvements have come to a standstill. Here we show the in situ nanoscale imaging of the growth and division of single bacterial cells on planar substrates with the atomic force microscope. To achieve this, we minimized the lateral shear forces responsible for the detachment of weakly adsorbed bacteria on planar substrates with the use of the so called dynamic jumping mode with very soft cantilever probes. With this approach, gentle imaging conditions can be maintained for long periods of time, enabling the continuous imaging of the bacterial cell growth and division, even on planar substrates. Present results offer the possibility to observe living processes of untrapped bacteria weakly attached to planar substrates. - Highlights: • Gelatine coatings used to weakly attach bacterial cells onto planar substrates. • Use of the dynamic jumping mode as a non-perturbing bacterial imaging mode. • Nanoscale resolution imaging of unperturbed single living bacterial cells. • Growth and division of single bacteria cells on planar substrates observed.

Pulmonary hypertension CT imaging

International Nuclear Information System (INIS)

Nedevska, A.

2013-01-01

Full text: The right heart catheterization is the gold standard in the diagnosis and determines the severity of pulmonary hypertension. The significant technical progress of noninvasive diagnostic imaging methods significantly improves the pixel density and spatial resolution in the study of cardiovascular structures, thus changes their role and place in the overall diagnostic plan. Learning points: What is the etiology, clinical manifestation and general pathophysiological disorders in pulmonary hypertension. What are the established diagnostic methods in the diagnosis and follow-up of patients with pulmonary hypertension. What is the recommended protocol for CT scanning for patients with clinically suspected or documented pulmonary hypertension. What are the important diagnostic findings in CT scan of a patient with pulmonary hypertension. Discussion: The prospect of instantaneous complex - anatomical and functional cardiopulmonary and vascular diagnostics seems extremely attractive. The contrast enhanced multislice computed (CT ) and magnetic resonance imaging are very suitable methods for imaging the structures of the right heart, with the possibility of obtaining multiple projections and three-dimensional imaging reconstructions . There are specific morphological features that, if carefully analyzed, provide diagnostic information. Thus, it is possible to avoid or at least reduce the frequency of use of invasive diagnostic cardiac catheterization in patients with pulmonary hypertension. Conclusion: This review focuses on the use of contrast-enhanced CT for comprehensive evaluation of patients with pulmonary hypertension and presents the observed characteristic changes in the chest, lung parenchyma , the structures of the right half of the heart and pulmonary vessels

Methods of X-ray CT image reconstruction from few projections

International Nuclear Information System (INIS)

Wang, H.

2011-01-01

To improve the safety (low dose) and the productivity (fast acquisition) of a X-ray CT system, we want to reconstruct a high quality image from a small number of projections. The classical reconstruction algorithms generally fail since the reconstruction procedure is unstable and suffers from artifacts. A new approach based on the recently developed 'Compressed Sensing' (CS) theory assumes that the unknown image is in some sense 'sparse' or 'compressible', and the reconstruction is formulated through a non linear optimization problem (TV/l1 minimization) by enhancing the sparsity. Using the pixel (or voxel in 3D) as basis, to apply the CS framework in CT one usually needs a 'sparsifying' transform, and combines it with the 'X-ray projector' which applies on the pixel image. In this thesis, we have adapted a 'CT-friendly' radial basis of Gaussian family called 'blob' to the CS-CT framework. The blob has better space-frequency localization properties than the pixel, and many operations, such as the X-ray transform, can be evaluated analytically and are highly parallelizable (on GPU platform). Compared to the classical Kaisser-Bessel blob, the new basis has a multi-scale structure: an image is the sum of dilated and translated radial Mexican hat functions. The typical medical objects are compressible under this basis, so the sparse representation system used in the ordinary CS algorithms is no more needed. 2D simulations show that the existing TV and l1 algorithms are more efficient and the reconstructions have better visual quality than the equivalent approach based on the pixel or wavelet basis. The new approach has also been validated on 2D experimental data, where we have observed that in general the number of projections can be reduced to about 50%, without compromising the image quality. (author) [fr

Stereoscopic Planar Laser-Induced Fluorescence Imaging at 500 kHz

Science.gov (United States)

Medford, Taylor L.; Danehy, Paul M.; Jones, Stephen B.; Jiang, N.; Webster, M.; Lempert, Walter; Miller, J.; Meyer, T.

2011-01-01

A new measurement technique for obtaining time- and spatially-resolved image sequences in hypersonic flows is developed. Nitric-oxide planar laser-induced fluorescence (NO PLIF) has previously been used to investigate transition from laminar to turbulent flow in hypersonic boundary layers using both planar and volumetric imaging capabilities. Low flow rates of NO were typically seeded into the flow, minimally perturbing the flow. The volumetric imaging was performed at a measurement rate of 10 Hz using a thick planar laser sheet that excited NO fluorescence. The fluorescence was captured by a pair of cameras having slightly different views of the flow. Subsequent stereoscopic reconstruction of these images allowed the three-dimensional flow structures to be viewed. In the current paper, this approach has been extended to 50,000 times higher repetition rates. A laser operating at 500 kHz excites the seeded NO molecules, and a camera, synchronized with the laser and fitted with a beam-splitting assembly, acquires two separate images of the flow. The resulting stereoscopic images provide three-dimensional flow visualizations at 500 kHz for the first time. The 200 ns exposure time in each frame is fast enough to freeze the flow while the 500 kHz repetition rate is fast enough to time-resolve changes in the flow being studied. This method is applied to visualize the evolving hypersonic flow structures that propagate downstream of a discrete protuberance attached to a flat plate. The technique was demonstrated in the NASA Langley Research Center s 31-Inch Mach 10 Air Tunnel facility. Different tunnel Reynolds number conditions, NO flow rates and two different cylindrical protuberance heights were investigated. The location of the onset of flow unsteadiness, an indicator of transition, was observed to move downstream during the tunnel runs, coinciding with an increase in the model temperature.

PT-symmetric planar devices for field transformation and imaging

International Nuclear Information System (INIS)

Valagiannopoulos, C A; Monticone, F; Alù, A

2016-01-01

The powerful tools of transformation optics (TO) allow an effective distortion of a region of space by carefully engineering the material inhomogeneity and anisotropy, and have been successfully applied in recent years to control electromagnetic fields in many different scenarios, e.g., to realize invisibility cloaks and planar lenses. For various field transformations, it is not necessary to use volumetric inhomogeneous materials, and suitably designed ultrathin metasurfaces with tailored spatial or spectral responses may be able to realize similar functionalities within smaller footprints and more robust mechanisms. Here, inspired by the concept of metamaterial TO lenses, we discuss field transformations enabled by parity-time (PT) symmetric metasurfaces, which can emulate negative refraction. We first analyze a simple realization based on homogeneous and local metasurfaces to achieve negative refraction and imaging, and we then extend our results to arbitrary PT-symmetric two-port networks to realize aberration-free planar imaging. (paper)

Ring artifacts removal from synchrotron CT image slices

International Nuclear Information System (INIS)

Wei Zhouping; Chapman, Dean; Wiebe, Sheldon

2013-01-01

Ring artifacts can occur in reconstructed images from x-ray Computerized Tomography (CT) as full or partial concentric rings superimposed on the scanned structures. Due to the data corruption by those ring artifacts in CT images, qualitative and quantitative analysis of these images are compromised. In this paper, we propose to correct the ring artifacts on the reconstructed synchrotron radiation (SR) CT image slices. The proposed correction procedure includes the following steps: (1). transform the reconstructed CT images into polar coordinates; (2) apply discrete two-dimensional (2D) wavelet transform to the polar image to decompose it into four image components: low pass band image component, as well as the components from horizontal, vertical and diagonal details bands; (3). apply 2D Fourier transform to the vertical details band image component only, since the ring artifacts become vertical lines in the polar coordinates; (4). apply Gaussian filtering in Fourier domain along the abscissa direction to suppress the vertical lines, since the information of the vertical lines in Fourier domain is completely condensed to that direction; (5). perform inverse Fourier transform to get the corrected vertical details band image component; (6). perform inverse wavelet transform to get the corrected polar image; (7). transform the corrected polar image back to Cartesian coordinates to get the CT image slice with reduced ring artifacts. This approach has been successfully used on CT data acquired from the Biomedical Imaging and Therapy (BMIT) beamline in Canadian Light Source (CLS), and the results show that the ring artifacts in original SR CT images have been effectively suppressed with all the structure information in the image preserved.

Pericardial sinuses and recesses effusion of 16-slice helical CT imaging and anatomic correlation

International Nuclear Information System (INIS)

Lu Chunyan; Yang Zhigang; Zhou Xiangping; Yu Jianqun; Zhu Jie; Yang Kaiqing

2007-01-01

Objective: To evaluate the CT features and implications of the pericardial sinuses and recesses effusion by combining the sectional cadavers and 16 multi-slice CT (MSCT) reformation. Methods: The anatomy and communication of the pericardial sinuses and recesses on the axial, coronal and saggital sectional cadavers (respectively 1 case), and the morphologic features on MSCT reformatted images in 104 patients were observed. The detection rate of effusion was analyzed. Results: The sectional cadavers and CT images showed that the pericardial sinuses and recesses were formed by the reflections of the pericardium on the root of the great vessels. The detection rate of the sinuses and recesses was lower in small effusion than in moderate and large effusion (P<0.05). The superior aortic recess was the most common recess for pericardial effusion. Conclusion: The MSCT reformatted images can show the morphologic features of pericardial sinuses and recesses effusion and communications with the pericardial cavity, help differentiate pericardial effusion from other mediastinal or pericardial lesions. (authors)

Impulse-response analysis of planar computed tomography for nondestructive test

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae Cheon; Kim, Seung Ho; Kim, Ho Kyung [KAERI, Daejeon (Korea, Republic of)

2016-05-15

There have been reported that the use of radiation imaging such as digital radiography, computed tomography (CT), and digital tomosynthesis (DTS) for the nondestructive test (NDT) widely is spreading. These methods have merits and demerits of their own, in terms of image quality and inspection speed. Therefore, image for these methods for NDT should have acceptable image quality and high speed. In this study, we quantitatively evaluate impulse responses of reconstructed images from the filtered backprojection (FBP), which are most widely used in planar computed tomography (pCT) systems. We first evaluate image performance metrics due to the contrast, depth resolution, and then we design the figure of merit including image performance and system parameters, such as tube load and reconstruction speed. The final goal of this study is the application of these methods to the nondestructive test. In order to accomplish it, further study is needed. First of all, the results of the ASF from various numbers of views. Second, the analysis of modulation transfer function, noise power spectrum, and detective quantum efficiency from various angular range and numbers of views.

CT urethrography. New imaging technique of the urethra

International Nuclear Information System (INIS)

Takeyama, Nobuyuki; Munechika, Hirotsugu

2005-01-01

The purpose of the study is to assess the usefulness of CT urethrography for evaluation of the posterior urethra and surrounding structures. The CT images were performed with 4 channel multidetector row CT unit. Twenty-six cases (12 cases of CT urethrography and 14 cases of conventional urethrography) were included in this study. 3D-volume rendering (VR) images and VR-multiplaner reconstruction (MPR) sagittal images were compared with conventional retrograde urethrography (RUG) images to evaluate the following anatomical structures; the inferior wall of bladder, the neck of bladder, the posterior urethra, and the prostate. Two radiologists undertook a task of evaluation of the images. There was no significant difference in image quality between RUG and 3D-VR. However, VR-MPR sagittal images were significantly better than RUG or 3D-VR images in any anatomical structures set up beforehand for evaluation. CT urerthrography was useful for evaluation of the posterior urethra and surrounding structures. (author)

Evaluation of Marfan syndrome: MR imaging versus CT

International Nuclear Information System (INIS)

Soulen, R.L.; Fishman, E.K.; Pyeritz, R.E.; Gott, V.L.; Zerhouni, E.A.

1986-01-01

Twenty-five patients with Marfan, syndrome underwent both CT and MR imaging. MR imaging were interpreted in blinded fashion and then compared with CT scans MR imaging was found to be equivalent to CT in the detection of aortic, dural, and hip abnormalities in patients not operated on. MR imaging was superior to CT in the evaluation of postoperative patients because the artifact produced by Bjork-Shirley or St. Jude valves precludes adequate evaluation of the aortic root on CT while producing only a small inferior field distortion (a ''pseudo-ventricular septal defect'') on MR imaging. The absence of radiation exposure is another major advantage of MR imaging in this relatively young population requiring serial studies. The authors conclude that MR imaging is the modality of choice for the evaluation and follow-up of patients with Marfan syndrome and offers an appropriate means of screening their kindred

Mass preserving image registration for lung CT

DEFF Research Database (Denmark)

Gorbunova, Vladlena; Sporring, Jon; Lo, Pechin Chien Pau

2012-01-01

This paper presents a mass preserving image registration algorithm for lung CT images. To account for the local change in lung tissue intensity during the breathing cycle, a tissue appearance model based on the principle of preservation of total lung mass is proposed. This model is incorporated...... on four groups of data: 44 pairs of longitudinal inspiratory chest CT scans with small difference in lung volume; 44 pairs of longitudinal inspiratory chest CT scans with large difference in lung volume; 16 pairs of expiratory and inspiratory CT scans; and 5 pairs of images extracted at end exhale and end...

Evaluation of diagnostic quality in musculoskeletal three-dimensional CT scans

International Nuclear Information System (INIS)

Vannier, M.W.; Hildebolt, C.F.; Gilula, L.A.; Sutherland, C.J.; Offutt, C.J.; Drebin, R.; Mantle, M.; Giordono, T.A.

1988-01-01

A major application of three-dimensional computed tomography (CT) is in the imaging of the skeleton. Three-dimensional CT has an important role in determining the presence and extent of congenital and acquired orthopedic abnormalities. The objective of this study was to compare the diagnostic sensitivity and specificity of three-dimensional CT, planar CT, and plain radiography in the detection and characterization of orthopedic abnormalities. Three-dimensional CT scan reconstructions were obtained by two methods, surface reconstruction and volumetric techniques. Seventy patients were imaged with CT, three-dimensional CT, and plain radiography. The consensus opinion of experts with access to all images plus clinical history, surgical findings, and follow-up findings were taken as truth. Expert radiologists read these cases in a blinded fashion. The results were compared using receiver operating characteristic (ROC) analysis. The diagnostic value of each three-dimensional reconstruction method and the parameters used to perform the reconstructions were evaluated

Functional magnetic resonance imaging by visual stimulation

International Nuclear Information System (INIS)

Nishimura, Yukiko; Negoro, Kiyoshi; Morimatsu, Mitsunori; Hashida, Masahiro

1996-01-01

We evaluated functional magnetic resonance images obtained in 8 healthy subjects in response to visual stimulation using a conventional clinical magnetic resonance imaging system with multi-slice spin-echo echo planar imaging. Activation in the visual cortex was clearly demonstrated by the multi-slice experiment with a task-related change in signal intensity. In addition to the primary visual cortex, other areas were also activated by a complicated visual task. Multi-slice spin-echo echo planar imaging offers high temporal resolution and allows the three-dimensional analysis of brain function. Functional magnetic resonance imaging provides a useful noninvasive method of mapping brain function. (author)

In vivo microCT imaging of rodent cerebral vasculature

International Nuclear Information System (INIS)

Seo, Youngho; Hasegawa, Bruce H; Hashimoto, Tomoki; Nuki, Yoshitsugu

2008-01-01

Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography ('microCT') system (FLEX(tm) X-O(tm), Gamma Medica-Ideas, Northridge, CA). For all in vivo studies, the head of the anesthetized rat was secured in a custom immobilization device for microCT imaging with 512 projections over 2 min at 60 kVp and 0.530 mA (I tube x t/rotation = 63.6 mAs). First, imaging without iodinated contrast was performed (a) to differentiate the effect of contrast agent in contrast-enhanced CT and (b) to examine the effectiveness of the immobilization device between two time points of CT acquisitions. Then, contrast-enhanced CT was performed with continuous administration of iopromide (300 mgI ml -1 at 1.2 ml min -1 ) to visualize aneurysms and other vascular formations in the carotid and cerebral arteries that may precede subarachnoid hemorrhage. The accuracy of registration between the noncontrast and contrast-enhanced CT images with the immobilization device was compared against the images aligned with normalized mutual information using FMRIB's linear image registration tool (FLIRT). Translations and rotations were examined between the FLIRT-aligned noncontrast CT image and the nonaligned noncontrast CT image. These two data sets demonstrated translational and rotational differences of less than 0.5 voxel (∼85 μm) and 0.5 deg., respectively. Noncontrast CT demonstrated a very small volume (0.1 ml) of femoral arterial blood introduced surgically into the rodent brain. Continuous administration of iopromide during the CT acquisition produced consistent vascular contrast in the reconstructed CT images. As a result, carotid arteries and major cerebral blood vessels

In vivo microCT imaging of rodent cerebral vasculature

Energy Technology Data Exchange (ETDEWEB)

Seo, Youngho; Hasegawa, Bruce H [Center for Molecular and Functional Imaging, Department of Radiology, University of California, San Francisco, CA 94143 (United States); Hashimoto, Tomoki; Nuki, Yoshitsugu [Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143 (United States)], E-mail: youngho.seo@radiology.ucsf.edu

2008-04-07

Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography ('microCT') system (FLEX(tm) X-O(tm), Gamma Medica-Ideas, Northridge, CA). For all in vivo studies, the head of the anesthetized rat was secured in a custom immobilization device for microCT imaging with 512 projections over 2 min at 60 kVp and 0.530 mA (I{sub tube} x t/rotation = 63.6 mAs). First, imaging without iodinated contrast was performed (a) to differentiate the effect of contrast agent in contrast-enhanced CT and (b) to examine the effectiveness of the immobilization device between two time points of CT acquisitions. Then, contrast-enhanced CT was performed with continuous administration of iopromide (300 mgI ml{sup -1} at 1.2 ml min{sup -1}) to visualize aneurysms and other vascular formations in the carotid and cerebral arteries that may precede subarachnoid hemorrhage. The accuracy of registration between the noncontrast and contrast-enhanced CT images with the immobilization device was compared against the images aligned with normalized mutual information using FMRIB's linear image registration tool (FLIRT). Translations and rotations were examined between the FLIRT-aligned noncontrast CT image and the nonaligned noncontrast CT image. These two data sets demonstrated translational and rotational differences of less than 0.5 voxel ({approx}85 {mu}m) and 0.5 deg., respectively. Noncontrast CT demonstrated a very small volume (0.1 ml) of femoral arterial blood introduced surgically into the rodent brain. Continuous administration of iopromide during the CT acquisition produced consistent vascular contrast in the reconstructed CT images. As a result, carotid

Fast in vivo bioluminescence tomography using a novel pure optical imaging technique

Directory of Open Access Journals (Sweden)

Shuang Zhang

2017-05-01

Full Text Available Bioluminescence tomography (BLT is a novel optical molecular imaging technique that advanced the conventional planar bioluminescence imaging (BLI into a quantifiable three-dimensional (3D approach in preclinical living animal studies in oncology. In order to solve the inverse problem and reconstruct tumor lesions inside animal body accurately, the prior structural information is commonly obtained from X-ray computed tomography (CT. This strategy requires a complicated hybrid imaging system, extensive post imaging analysis and involvement of ionizing radiation. Moreover, the overall robustness highly depends on the fusion accuracy between the optical and structural information. Here, we present a pure optical bioluminescence tomographic (POBT system and a novel BLT workflow based on multi-view projection acquisition and 3D surface reconstruction. This method can reconstruct the 3D surface of an imaging subject based on a sparse set of planar white-light and bioluminescent images, so that the prior structural information can be offered for 3D tumor lesion reconstruction without the involvement of CT. The performance of this novel technique was evaluated through the comparison with a conventional dual-modality tomographic (DMT system and a commercialized optical imaging system (IVIS Spectrum using three breast cancer xenografts. The results revealed that the new technique offered comparable in vivo tomographic accuracy with the DMT system (P>0.05 in much shorter data analysis time. It also offered significantly better accuracy comparing with the IVIS system (P<0.04 without sacrificing too much time.

Neural network and its application to CT imaging

Energy Technology Data Exchange (ETDEWEB)

Nikravesh, M.; Kovscek, A.R.; Patzek, T.W. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-02-01

We present an integrated approach to imaging the progress of air displacement by spontaneous imbibition of oil into sandstone. We combine Computerized Tomography (CT) scanning and neural network image processing. The main aspects of our approach are (I) visualization of the distribution of oil and air saturation by CT, (II) interpretation of CT scans using neural networks, and (III) reconstruction of 3-D images of oil saturation from the CT scans with a neural network model. Excellent agreement between the actual images and the neural network predictions is found.

Prior image constrained image reconstruction in emerging computed tomography applications

Science.gov (United States)

Brunner, Stephen T.

Advances have been made in computed tomography (CT), especially in the past five years, by incorporating prior images into the image reconstruction process. In this dissertation, we investigate prior image constrained image reconstruction in three emerging CT applications: dual-energy CT, multi-energy photon-counting CT, and cone-beam CT in image-guided radiation therapy. First, we investigate the application of Prior Image Constrained Compressed Sensing (PICCS) in dual-energy CT, which has been called "one of the hottest research areas in CT." Phantom and animal studies are conducted using a state-of-the-art 64-slice GE Discovery 750 HD CT scanner to investigate the extent to which PICCS can enable radiation dose reduction in material density and virtual monochromatic imaging. Second, we extend the application of PICCS from dual-energy CT to multi-energy photon-counting CT, which has been called "one of the 12 topics in CT to be critical in the next decade." Numerical simulations are conducted to generate multiple energy bin images for a photon-counting CT acquisition and to investigate the extent to which PICCS can enable radiation dose efficiency improvement. Third, we investigate the performance of a newly proposed prior image constrained scatter correction technique to correct scatter-induced shading artifacts in cone-beam CT, which, when used in image-guided radiation therapy procedures, can assist in patient localization, and potentially, dose verification and adaptive radiation therapy. Phantom studies are conducted using a Varian 2100 EX system with an on-board imager to investigate the extent to which the prior image constrained scatter correction technique can mitigate scatter-induced shading artifacts in cone-beam CT. Results show that these prior image constrained image reconstruction techniques can reduce radiation dose in dual-energy CT by 50% in phantom and animal studies in material density and virtual monochromatic imaging, can lead to radiation

Computed tomography whole body imaging in multi-trauma: 7 years experience

Energy Technology Data Exchange (ETDEWEB)

Sampson, M.A. [Southampton General Hospital, Southampton (United Kingdom)]. E-mail: msampson@doctors.org.uk; Colquhoun, K.B.M. [Southampton General Hospital, Southampton (United Kingdom); Hennessy, N.L.M. [Southampton General Hospital, Southampton (United Kingdom)

2006-04-15

AIM: To assess the impact of the introduction of a computed tomography (CT) imaging protocol for multi-trauma patients on the workload, overall diagnostic yield, and effect on detection of cervical spine injury and pneumothorax. METHOD: Between February 1997 and April 2004, all patients presenting acutely to the Emergency Department (ED) with haemodynamically stable trauma (Abbreviated Injury Scale 3 or more) involving more than two body systems were imaged with a comprehensive pre-set helical CT protocol (including non-contrast head, cervical spine: cranio-cervical and cervico-thoracic junctions; and oral and intravenous contrast-enhanced thoracic, abdomen and pelvis) after initial triage and a standard trauma series of radiographs (chest, lateral C-spine and pelvis). Diagnosis of cervical spine fracture and pneumothorax was noted before and after the CT protocol was carried out and findings from all studies were recorded prospectively. RESULTS: Over the 7-year period 296 multi-trauma CT studies were completed of which 41 (13.8%) were negative. Of the positive cases there were 127 (43%) head injuries; 25 cervical spine fractures (8%); 66 pelvic fractures (22%);48 thoracic or lumbar spine fractures (16%); 97 pneumothoraces (33%); 22 mediastinal injuries (7%) and 49 intra-abdominal injuries (17%) with 19 (6%) splenic tears/ruptures. Positive findings included many unsuspected injuries, including 19 cervical spine fractures which were not demonstrated on the standard lateral radiograph from the resuscitation room. Of the 97 CT detected pneumothoraces, 12 were bilateral, 52 already had a chest drain in situ and 36 were not detected on initial supine chest radiography in the resuscitation room. One undetected case had bilateral tension pneumothoraces that were promptly drained on the CT table. Only three patients did not complete their multi-trauma examination because of deterioration in clinical condition and these were all immediately returned to the resuscitation

Computed tomography whole body imaging in multi-trauma: 7 years experience

International Nuclear Information System (INIS)

Sampson, M.A.; Colquhoun, K.B.M.; Hennessy, N.L.M.

2006-01-01

AIM: To assess the impact of the introduction of a computed tomography (CT) imaging protocol for multi-trauma patients on the workload, overall diagnostic yield, and effect on detection of cervical spine injury and pneumothorax. METHOD: Between February 1997 and April 2004, all patients presenting acutely to the Emergency Department (ED) with haemodynamically stable trauma (Abbreviated Injury Scale 3 or more) involving more than two body systems were imaged with a comprehensive pre-set helical CT protocol (including non-contrast head, cervical spine: cranio-cervical and cervico-thoracic junctions; and oral and intravenous contrast-enhanced thoracic, abdomen and pelvis) after initial triage and a standard trauma series of radiographs (chest, lateral C-spine and pelvis). Diagnosis of cervical spine fracture and pneumothorax was noted before and after the CT protocol was carried out and findings from all studies were recorded prospectively. RESULTS: Over the 7-year period 296 multi-trauma CT studies were completed of which 41 (13.8%) were negative. Of the positive cases there were 127 (43%) head injuries; 25 cervical spine fractures (8%); 66 pelvic fractures (22%);48 thoracic or lumbar spine fractures (16%); 97 pneumothoraces (33%); 22 mediastinal injuries (7%) and 49 intra-abdominal injuries (17%) with 19 (6%) splenic tears/ruptures. Positive findings included many unsuspected injuries, including 19 cervical spine fractures which were not demonstrated on the standard lateral radiograph from the resuscitation room. Of the 97 CT detected pneumothoraces, 12 were bilateral, 52 already had a chest drain in situ and 36 were not detected on initial supine chest radiography in the resuscitation room. One undetected case had bilateral tension pneumothoraces that were promptly drained on the CT table. Only three patients did not complete their multi-trauma examination because of deterioration in clinical condition and these were all immediately returned to the resuscitation

Three-dimensional ground penetrating radar imaging using multi-frequency diffraction tomography

Energy Technology Data Exchange (ETDEWEB)

Mast, J.E.; Johansson, E.M. [Lawrence Livermore National Lab., CA (United States)

1994-11-15

In this talk we present results from a three-dimensional image reconstruction algorithm for impulse radar operating in monostatic pule-echo mode. The application of interest to us is the nondestructive evaluation of civil structures such as bridge decks. We use a multi-frequency diffraction tomography imaging technique in which coherent backward propagations of the received reflected wavefield form a spatial image of the scattering interfaces within the region of interest. This imaging technique provides high-resolution range and azimuthal visualization of the subsurface region. We incorporate the ability to image in planarly layered conductive media and apply the algorithm to experimental data from an offset radar system in which the radar antenna is not directly coupled to the surface of the region. We present a rendering in three-dimensions of the resulting image data which provides high-detail visualization.

Interior tomography in microscopic CT with image reconstruction constrained by full field of view scan at low spatial resolution

Science.gov (United States)

Luo, Shouhua; Shen, Tao; Sun, Yi; Li, Jing; Li, Guang; Tang, Xiangyang

2018-04-01

In high resolution (microscopic) CT applications, the scan field of view should cover the entire specimen or sample to allow complete data acquisition and image reconstruction. However, truncation may occur in projection data and results in artifacts in reconstructed images. In this study, we propose a low resolution image constrained reconstruction algorithm (LRICR) for interior tomography in microscopic CT at high resolution. In general, the multi-resolution acquisition based methods can be employed to solve the data truncation problem if the project data acquired at low resolution are utilized to fill up the truncated projection data acquired at high resolution. However, most existing methods place quite strict restrictions on the data acquisition geometry, which greatly limits their utility in practice. In the proposed LRICR algorithm, full and partial data acquisition (scan) at low and high resolutions, respectively, are carried out. Using the image reconstructed from sparse projection data acquired at low resolution as the prior, a microscopic image at high resolution is reconstructed from the truncated projection data acquired at high resolution. Two synthesized digital phantoms, a raw bamboo culm and a specimen of mouse femur, were utilized to evaluate and verify performance of the proposed LRICR algorithm. Compared with the conventional TV minimization based algorithm and the multi-resolution scout-reconstruction algorithm, the proposed LRICR algorithm shows significant improvement in reduction of the artifacts caused by data truncation, providing a practical solution for high quality and reliable interior tomography in microscopic CT applications. The proposed LRICR algorithm outperforms the multi-resolution scout-reconstruction method and the TV minimization based reconstruction for interior tomography in microscopic CT.

A Prospective Study Comparing 99mTc-Hydroxyethylene-Diphosphonate Planar Bone Scintigraphy and Whole-Body SPECT/CT with 18F-Fluoride PET/CT and 18F-Fluoride PET/MRI for Diagnosing Bone Metastases.

Science.gov (United States)

Löfgren, Johan; Mortensen, Jann; Rasmussen, Sine H; Madsen, Claus; Loft, Annika; Hansen, Adam E; Oturai, Peter; Jensen, Karl Erik; Mørk, Mette Louise; Reichkendler, Michala; Højgaard, Liselotte; Fischer, Barbara M

2017-11-01

We prospectively evaluated and compared the diagnostic performance of 99m Tc-hydroxyethylene-diphosphonate ( 99m Tc-HDP) planar bone scintigraphy (pBS), 99m Tc-HDP SPECT/CT, 18 F-NaF PET/CT, and 18 F-NaF PET/MRI for the detection of bone metastases. Methods: One hundred seventeen patients with histologically proven malignancy referred for clinical pBS were prospectively enrolled. pBS and whole-body SPECT/CT were performed followed by 18 F-NaF PET/CT within 9 d. 18 F-NaF PET/MRI was also performed in 46 patients. Results: Bone metastases were confirmed in 16 patients and excluded in 101, which was lower than expected. The number of equivocal scans was significantly higher for pBS than for SPECT/CT and PET/CT (18 vs. 5 and 6, respectively; P = 0.004 and 0.01, respectively). When equivocal readings were excluded, no statistically significant difference in sensitivity, specificity, positive predictive value, negative predictive value, or overall accuracy were found when comparing the different imaging techniques. In the per-patient analysis, equivocal scans were either assumed positive for metastases ("pessimistic analysis") or assumed negative for metastases ("optimistic analysis"). The percentages of misdiagnosed patients for the pessimistic analysis were 21%, 15%, 9%, and 7% for pBS, SPECT/CT, PET/CT, and PET/MRI, respectively. Corresponding figures for the optimistic analysis were 9%, 12%, 5%, and 7%. In those patients identified as having bone metastases according to the reference standard, SPECT/CT, 18 F-NaF PET/CT, and PET/MRI detected additional lesions compared with pBS in 31%, 63%, and 71%, respectively. Conclusion: 18 F-NaF PET/CT and whole-body SPECT/CT resulted in a significant reduction of equivocal readings compared with pBS, which implies an improved diagnostic confidence. However, the clinical benefit of using, for example, 18 F-NaF PET/CT or PET/MRI as compared with SPECT/CT and pBS in this patient population with a relatively low prevalence of bone

Quantitative pre-surgical lung function estimation with SPECT/CT

International Nuclear Information System (INIS)

Bailey, D. L.; Willowson, K. P.; Timmins, S.; Harris, B. E.; Bailey, E. A.; Roach, P. J.

2009-01-01

Full text:Objectives: To develop methodology to predict lobar lung function based on SPECT/CT ventilation and perfusion (V/Q) scanning in candidates for lobectomy for lung cancer. Methods: This combines two development areas from our group: quantitative SPECT based on CT-derived corrections for scattering and attenuation of photons, and SPECT V/Q scanning with lobar segmentation from CT. Eight patients underwent baseline pulmonary function testing (PFT) including spirometry, measure of DLCO and cario-pulmonary exercise testing. A SPECT/CT V/Q scan was acquired at baseline. Using in-house software each lobe was anatomically defined using CT to provide lobar ROIs which could be applied to the SPECT data. From these, individual lobar contribution to overall function was calculated from counts within the lobe and post-operative FEV1, DLCO and VO2 peak were predicted. This was compared with the quantitative planar scan method using 3 rectangular ROIs over each lung. Results: Post-operative FEV1 most closely matched that predicted by the planar quantification method, with SPECT V/Q over-estimating the loss of function by 8% (range - 7 - +23%). However, post-operative DLCO and VO2 peak were both accurately predicted by SPECT V/Q (average error of 0 and 2% respectively) compared with planar. Conclusions: More accurate anatomical definition of lobar anatomy provides better estimates of post-operative loss of function for DLCO and VO2 peak than traditional planar methods. SPECT/CT provides the tools for accurate anatomical defintions of the surgical target as well as being useful in producing quantitative 3D functional images for ventilation and perfusion.

Usefulness of Ga-67 citrate whole body imaging, chest spot imaging, and chest SPECT in sarcoidosis

International Nuclear Information System (INIS)

Ueno, Kyoichi; Nishi, Koichi; Namura, Masanobu; Kawashima, Yoshio; Kurumaya, Hiroshi

1999-01-01

To assess the sensitivity, and the relative role of Ga-67 whole body, chest spot imaging, and chest SPECT, we retrospectively studied 34 cases of sarcoidosis (24 biopsy proven, 10 clinically diagnosed) with Ga-67 (111 MBq), and compared the results of lung (25 cases), muscle (25 cases), skin (3 cases), and myocardial (2 cases) biopsies. Ga-67 chest SPECT (single photon emission CT) were done in 17 cases with Siemens MultiSPECT3. Ga-67 planar imaging visualized only 2 of 12 (16.7%) lung biopsy-positive cases, 5 of 12 (41.6%) muscle biopsy-positive cases, 2 of 3 (66.7%) skin biopsy-positive cases. However, Ga-67 imaging revealed the lesions in 1 of 9 (11.1%) of muscle biopsy-negative cases, in 2 of 3 (66.7%) of skin biopsy-negative cases, and in 1 of 2 myocardial biopsy-negative cases. Ga-67 chest SPECT visualized 14 hilar lymphadenopathy (LN), 3 supraclavicular LN, and 1 myocardial sarcoidosis. Although both SPECT, and planar spot imaging detected the lesions equally, the former showed them more clearly. Compared with various biopsies, the sensitivity of Ga-67 imaging was not so high. However, Ga-67 imaging is non-invasive, easy to perform the whole body imaging, and can detect the activity of the lesions. Ga-67 SPECT showed clear imaging of the hilar, mediastinal LN, and potentially fatal myocardial sarcoidosis. (author)

Clinical efficiency, image quality and dosimetric considerations

Energy Technology Data Exchange (ETDEWEB)

Arreola, M. [Director of Clinical Radiological Physics, Shands Hospital at the University of Florida College of Medicine, Gainesville, FL (United States)

2000-07-01

Three decades have passed since the first clinical use of the famous EMI Computed Axial Tomography (Cat) scanner. At the time, the prospects for clinical success of this innovative idea were not very good. Time, however, has proven otherwise as what is now simply known as Computed tomography (CT) has been boosted in each one of these decades for different reasons. In the 1970s, technological progress augmented by the realization of the importance of tomographic imaging got everything started; in the 1980s, the boom in health care demand in the US solidified its position and in the 1990s the technological explosion in computers and the imperative need to lower costs in the health care industry have prompted the most dramatic changes in the wy CT is utilized in the year 2000. Thus, different motivations have led the way of progress in CT at various times, and in spite of amazing developments in other crucial imaging modalities, such as ultrasound, Doppler ultrasound, digital subtraction angiography and magnetic resonance imaging, CT maintains its rightful place as the premiere imaging modality in the modern radiology department. This work covers the basic principles of tomographic image reconstruction, and how axial CT scanners progressed historically in the first two decades. Developments in X-ray tubes, and detection systems are highlighted, as well as the impact of clinical efficiency, image quality and patient doses. The basic construction of translate-rotate (1st and 2nd generation), rotate-rotate (3rd generation) and detector ring (4th generation) scanners are described. The so-called 5th generation scanner, the electron beam scanner, is also described, with its clinical and technical advantages and its inherent financial and maintenance disadvantages, which brought the advent of spiral and multi-slice scanners. These most recent developments in CT technology have opened a new era in the clinical use of CT; and although image quality has reached an expected

Clinical efficiency, image quality and dosimetric considerations

International Nuclear Information System (INIS)

Arreola, M.

2000-01-01

Three decades have passed since the first clinical use of the famous EMI Computed Axial Tomography (Cat) scanner. At the time, the prospects for clinical success of this innovative idea were not very good. Time, however, has proven otherwise as what is now simply known as Computed tomography (CT) has been boosted in each one of these decades for different reasons. In the 1970s, technological progress augmented by the realization of the importance of tomographic imaging got everything started; in the 1980s, the boom in health care demand in the US solidified its position and in the 1990s the technological explosion in computers and the imperative need to lower costs in the health care industry have prompted the most dramatic changes in the wy CT is utilized in the year 2000. Thus, different motivations have led the way of progress in CT at various times, and in spite of amazing developments in other crucial imaging modalities, such as ultrasound, Doppler ultrasound, digital subtraction angiography and magnetic resonance imaging, CT maintains its rightful place as the premiere imaging modality in the modern radiology department. This work covers the basic principles of tomographic image reconstruction, and how axial CT scanners progressed historically in the first two decades. Developments in X-ray tubes, and detection systems are highlighted, as well as the impact of clinical efficiency, image quality and patient doses. The basic construction of translate-rotate (1st and 2nd generation, rotate-rotate (3rd generation) and detector ring (4th generation) scanners are described. The so-called 5th generation scanner, the electron beam scanner, is also described, with its clinical and technical advantages and its inherent financial and maintenance disadvantages, which brought the advent of spiral and multi-slice scanners. These most recent developments in CT technology have opened a new era in the clinical use of CT; and although image quality has reached an expected

Application of triple rule-out with 64-slice spiral CT in the diagnosis of acute chest pain

International Nuclear Information System (INIS)

Li Pengyu; Li Kuncheng; Du Xiangyin; Cao Lizhen; Liu Jiabin; Yang Yanhuui; Liang Zhigang; Zhu Xiaolian; Liu Jian

2007-01-01

Objective: To investigate the performance of triple rule-out with 64-slice spiral CT in the combined examination of pulmonary artery, thoracic aorta and coronary artery for patients with acute chest pain. Methods: Seventy patients who presented with acute chest pain were included in the study. All of the patients underwent retrospective ECG-gated 64-slice computed tomography triple rule-out examination to evaluate the pulmonary arteries, thoracic aorta and coronary arteries. Multi-planar reconstruction (MPR), maximum intensity projection (MIP), curved-planar reconstruction (CPR) and volume rendering (VR) were used to display pulmonary arteries, thoracic aorta and coronary arteries. We evaluated the image quality of coronary artery and the enhancement of the pulmonary artery and thoracic aorta to estimate if the examination can fulfill the clinical demand for the differential diagnosis of acute chest pain. Results: The mean scan time was (8.5±1.0) s, and the dose of contrast medium injected was 100 ml. There were 95.7% (67/70) of patients whose CT values detected in the pulmonary artery and thoracic aorta after enhancement Were ≥200 HU. The image quality of 85.8% (720/839) coronary segments was classified as excellent, 8.6% (72/839) as good, and 5.6% (47/839) as poor. There were 20 eases with coronary stenoses ≥50%, 2 cases with pulmonary embolism, and 2 cases with aortic dissection. Conclusion: The triple rule-out examination with 64-slice spiral CT could depict pulmonary artery, thoracic aorta, and coronary artery in 8 s with good image quality. It has great potential in the etiological diagnosis for the patients with acute chest pain. (authors)