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Visualization of small visceral arteries on abdominal CT angiography using ultra-high-resolution CT scanner. Jpn J Radiol 2021; 39:889-897. [PMID: 33948788 PMCID: PMC8413175 DOI: 10.1007/s11604-021-01124-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 04/15/2021] [Indexed: 01/12/2023]
Abstract
PURPOSE To evaluate the image quality and ability to delineate the small visceral arteries of high-resolution (HR) abdominal CT angiography (CTA) using an ultra-high-resolution computed tomography (UHR CT) scanner. MATERIALS AND METHODS Thirty-seven patients were enrolled who underwent abdominal CTA using a UHR CT scanner. The images were reconstructed with a matrix of 1024 × 1024 and 0.25 mm thickness for HR CTA and with a matrix of 512 × 512 and 0.5 mm thickness for normal resolution (NR) CTA. Maximum CT value, image quality, and delineation of the small arteries were compared between HR CTA and NR CTA. RESULTS HR CTA showed significantly higher maximum CT value, higher image quality, and better delineation of the small arteries than did NR CTA (P < .005). CONCLUSION HR CTA using a UHR CT scanner showed higher image quality than NR CTA and enhanced the delineation of visceral arteries.
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Tuncay V, Vliegenthart R, den Dekker MAM, de Jonge GJ, van Zandwijk JK, van der Harst P, Oudkerk M, van Ooijen PMA. Non-invasive assessment of coronary artery geometry using coronary CTA. J Cardiovasc Comput Tomogr 2018; 12:257-260. [PMID: 29486988 DOI: 10.1016/j.jcct.2018.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 02/12/2018] [Indexed: 10/18/2022]
Abstract
AIM To assess the association of coronary artery geometry with the severity of coronary artery disease (CAD). METHODS 73 asymptomatic individuals at increased risk of CAD due to peripheral vascular disease (18 women, mean age 63.5 ± 8.2 years) underwent coronary computed tomography angiography (coronary CTA) using first generation dual-source CT. Curvature and tortuosity of the coronary arteries were quantified using semi-automatically generated centerlines. Measurements were performed for individual segments and for the entire artery. Coronary segments were labeled according to the presence of significant stenosis, defined as >70% luminal narrowing, and the presence of plaque. Comparisons were made by segment and by artery, using linear mixed models. RESULTS Overall, median curvature and tortuosity were, respectively, 0.094 [0.071; 0.120] and 1.080 [1.040; 1.120] on a per-segment level, and 0.096 [0.078; 0.118] and 1.175 [1.090; 1.420] on a per-artery level. Curvature was associated with significant stenosis at a per-segment (p < 0.001) and per-artery level (p = 0.002). Curvature was 16.7% higher for segments with stenosis, and 13.8% higher for arteries with stenosis. Tortuosity was associated with significant stenosis only at the per-segment level (p = 0.002). Curvature was related to the presence of plaque at the per-segment (p < 0.001) and per-artery level (p < 0.001), tortuosity was only related to plaque at the per-segment level (p < 0.001). CONCLUSION Coronary artery geometry as derived from coronary CTA is related to the presence of plaque and significant stenosis.
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Affiliation(s)
- V Tuncay
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands (CMI-NEN), Department of Radiology, The Netherlands
| | - R Vliegenthart
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands (CMI-NEN), Department of Radiology, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Radiology, The Netherlands
| | - M A M den Dekker
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands (CMI-NEN), Department of Radiology, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Radiology, The Netherlands
| | - G J de Jonge
- University of Groningen, University Medical Center Groningen, Department of Radiology, The Netherlands
| | - J K van Zandwijk
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands (CMI-NEN), Department of Radiology, The Netherlands; University of Twente, Technical Medicine Faculty, The Netherlands
| | - P van der Harst
- University of Groningen, University Medical Center Groningen, Cardiology, The Netherlands
| | - M Oudkerk
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands (CMI-NEN), Department of Radiology, The Netherlands
| | - P M A van Ooijen
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands (CMI-NEN), Department of Radiology, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Radiology, The Netherlands.
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Abstract
Resumo Softwares tradicionais de avaliação de imagens médicas, como DICOM, possuem diversas ferramentas para mensuração de distância, área e volume. Nenhuma delas permite medir distâncias entre pontos em superfícies. O menor trajeto entre pontos possibilita o cálculo entre óstios de vasos, como no caso de aneurismas aórticos, e a avaliação dos vasos viscerais para planejamento cirúrgico. O desenvolvimento de um plugin para OsiriX para mensuração de distâncias em superfícies mostrou-se factível. A validação da ferramenta ainda se faz necessária.
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Rubin GD. Computed tomography: revolutionizing the practice of medicine for 40 years. Radiology 2015; 273:S45-74. [PMID: 25340438 DOI: 10.1148/radiol.14141356] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Computed tomography (CT) has had a profound effect on the practice of medicine. Both the spectrum of clinical applications and the role that CT has played in enhancing the depth of our understanding of disease have been profound. Although almost 90 000 articles on CT have been published in peer-reviewed journals over the past 40 years, fewer than 5% of these have been published in Radiology. Nevertheless, these almost 4000 articles have provided a basis for many important medical advances. By enabling a deepened understanding of anatomy, physiology, and pathology, CT has facilitated key advances in the detection and management of disease. This article celebrates this breadth of scientific discovery and development by examining the impact that CT has had on the diagnosis, characterization, and management of a sampling of major health challenges, including stroke, vascular diseases, cancer, trauma, acute abdominal pain, and diffuse lung diseases, as related to key technical advances in CT and manifested in Radiology.
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Affiliation(s)
- Geoffrey D Rubin
- From the Duke Clinical Research Institute and Department of Radiology, Duke University School of Medicine, PO Box 17969, 2400 Pratt St, Durham, NC 27715
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Zhou C, Chan HP, Chughtai A, Kuriakose J, Agarwal P, Kazerooni EA, Hadjiiski LM, Patel S, Wei J. Computerized analysis of coronary artery disease: performance evaluation of segmentation and tracking of coronary arteries in CT angiograms. Med Phys 2014; 41:081912. [PMID: 25086543 PMCID: PMC4111838 DOI: 10.1118/1.4890294] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 06/08/2014] [Accepted: 07/02/2014] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The authors are developing a computer-aided detection system to assist radiologists in analysis of coronary artery disease in coronary CT angiograms (cCTA). This study evaluated the accuracy of the authors' coronary artery segmentation and tracking method which are the essential steps to define the search space for the detection of atherosclerotic plaques. METHODS The heart region in cCTA is segmented and the vascular structures are enhanced using the authors' multiscale coronary artery response (MSCAR) method that performed 3D multiscale filtering and analysis of the eigenvalues of Hessian matrices. Starting from seed points at the origins of the left and right coronary arteries, a 3D rolling balloon region growing (RBG) method that adapts to the local vessel size segmented and tracked each of the coronary arteries and identifies the branches along the tracked vessels. The branches are queued and subsequently tracked until the queue is exhausted. With Institutional Review Board approval, 62 cCTA were collected retrospectively from the authors' patient files. Three experienced cardiothoracic radiologists manually tracked and marked center points of the coronary arteries as reference standard following the 17-segment model that includes clinically significant coronary arteries. Two radiologists visually examined the computer-segmented vessels and marked the mistakenly tracked veins and noisy structures as false positives (FPs). For the 62 cases, the radiologists marked a total of 10191 center points on 865 visible coronary artery segments. RESULTS The computer-segmented vessels overlapped with 83.6% (8520/10191) of the center points. Relative to the 865 radiologist-marked segments, the sensitivity reached 91.9% (795/865) if a true positive is defined as a computer-segmented vessel that overlapped with at least 10% of the reference center points marked on the segment. When the overlap threshold is increased to 50% and 100%, the sensitivities were 86.2% and 53.4%, respectively. For the 62 test cases, a total of 55 FPs were identified by radiologist in 23 of the cases. CONCLUSIONS The authors' MSCAR-RBG method achieved high sensitivity for coronary artery segmentation and tracking. Studies are underway to further improve the accuracy for the arterial segments affected by motion artifacts, severe calcified and noncalcified soft plaques, and to reduce the false tracking of the veins and other noisy structures. Methods are also being developed to detect coronary artery disease along the tracked vessels.
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Affiliation(s)
- Chuan Zhou
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Heang-Ping Chan
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Aamer Chughtai
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Jean Kuriakose
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Prachi Agarwal
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Ella A Kazerooni
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
| | | | - Smita Patel
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Jun Wei
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109
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Rubin GD, Leipsic J, Joseph Schoepf U, Fleischmann D, Napel S. CT angiography after 20 years: a transformation in cardiovascular disease characterization continues to advance. Radiology 2014; 271:633-52. [PMID: 24848958 DOI: 10.1148/radiol.14132232] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Through a marriage of spiral computed tomography (CT) and graphical volumetric image processing, CT angiography was born 20 years ago. Fueled by a series of technical innovations in CT and image processing, over the next 5-15 years, CT angiography toppled conventional angiography, the undisputed diagnostic reference standard for vascular disease for the prior 70 years, as the preferred modality for the diagnosis and characterization of most cardiovascular abnormalities. This review recounts the evolution of CT angiography from its development and early challenges to a maturing modality that has provided unique insights into cardiovascular disease characterization and management. Selected clinical challenges, which include acute aortic syndromes, peripheral vascular disease, aortic stent-graft and transcatheter aortic valve assessment, and coronary artery disease, are presented as contrasting examples of how CT angiography is changing our approach to cardiovascular disease diagnosis and management. Finally, the recently introduced capabilities for multispectral imaging, tissue perfusion imaging, and radiation dose reduction through iterative reconstruction are explored with consideration toward the continued refinement and advancement of CT angiography.
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Affiliation(s)
- Geoffrey D Rubin
- From the Duke Clinical Research Institute, 2400 Pratt St, Box 17969, Durham, NC 27715 (G.D.R.); Department of Medical Imaging and Division of Cardiology, University of British Columbia, Vancouver, BC, Canada (J.L.); Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (U.J.S.); and Department of Radiology, Stanford University School of Medicine, Stanford, Calif (D.F., S.N.)
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Ghatwary TMH, Patterson BO, Karthikesalingam A, Hinchliffe RJ, Loftus IM, Morgan R, Thompson MM, Holt PJE. A systematic review of protocols for the three-dimensional morphologic assessment of abdominal aortic aneurysms using computed tomographic angiography. Cardiovasc Intervent Radiol 2013; 36:14-24. [PMID: 22159906 DOI: 10.1007/s00270-011-0296-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 10/09/2011] [Indexed: 10/14/2022]
Abstract
The morphology of infrarenal abdominal aortic aneurysms (AAAs) directly influences the perioperative outcome and long-term durability of endovascular aneurysm repair. A variety of methods have been proposed for the characterization of AAA morphology using reconstructed three-dimensional (3D) computed tomography (CT) images. At present, there is lack of consensus as to which of these methods is most applicable to clinical practice or research. The purpose of this review was to evaluate existing protocols that used 3D CT images in the assessment of various aspects of AAA morphology. An electronic search was performed, from January 1996 to the end of October 2010, using the Embase and Medline databases. The literature review conformed to PRISMA statement standards. The literature search identified 604 articles, of which 31 studies met inclusion criteria. Only 15 of 31 studies objectively assessed reproducibility. Existing published protocols were insufficient to define a single evidence-based methodology for preoperative assessment of AAA morphology. Further development and expert consensus are required to establish a standardized and validated protocol to determine precisely how morphology relates to outcomes after endovascular aneurysm repair.
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Affiliation(s)
- Tamer M H Ghatwary
- Department of Outcomes Research, St. George's Vascular Institute, St. George's Hospital, Blackshaw Road, London, SW17 0QT, UK
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Nijhof WH, van der Vos CS, Anninga B, Stegehuis PL, Jager GJ, Rutten MJ. Reduced contrast medium in abdominal aorta CTA using a multiphasic injection technique. Eur J Radiol 2013; 82:252-7. [DOI: 10.1016/j.ejrad.2012.09.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Revised: 09/27/2012] [Accepted: 09/30/2012] [Indexed: 11/26/2022]
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Role of multi-slice CT angiography versus Doppler ultrasonography and conventional angiography in assessment of aorto-iliac arterial disease. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2012. [DOI: 10.1016/j.ejrnm.2012.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Assessment of vascular contrast and depiction of stenoses in abdominopelvic and lower extremity vasculature: comparison of dual-energy MDCT with digital subtraction angiography. Acad Radiol 2012; 19:1149-57. [PMID: 22743115 DOI: 10.1016/j.acra.2012.04.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/12/2012] [Accepted: 04/13/2012] [Indexed: 12/22/2022]
Abstract
RATIONALE AND OBJECTIVES To assess whether dual-energy computed tomography (DECT) multidetector computed tomography (MDCT) angiography improves vascular contrast beyond MDCT angiography and digital subtraction angiography (DSA) while preserving the ability to precisely characterize stenoses, using DSA as reference standard. MATERIALS AND METHODS This prospective, Health Insurance Portability and Accountability Act-compliant, institutional review board-approved study was performed on 25 patients referred for lower extremity DECT angiography and subsequent DSA. Spectral data were postprocessed to create single-energy 120 kVp (MDCT series) and iodine-only (DECT series) datasets. The arterial tree was subdivided into 11 anatomical levels. Contrast-to-noise ratios (CNR) and corresponding coefficient -of variation (CV) of patent vessel segments were evaluated for DECT, MDCT, and DSA using analysis of variance comparisons. Degree of stenoses was determined for DECT, MDCT, and DSA and correlated with t-test, bivariate Pearson comparisons, and Bland-Altman plots. RESULTS Patent vasculature comprised 230 vessel segments. From infrarenal aorta to distal femoral arteries, DECT showed higher CNR compared to DSA and MDCT (P < .05); distal to the popliteal arteries, DSA achieved higher CNR (P < .05). Analyses of contrast homogeneity showed minimal CV above the knee for MDCT (≤9%) and for DSA below the knee (≤7%). Stenotic vasculature comprised 33 segments. Significant correlations of stenosis severity were found comparing DECT and MDCT with DSA as reference standard showing a 0.04-fold mean underestimation of stenoses on MDCT and no detectable mean variation on DECT compared with DSA. CONCLUSION DECT angiography improved contrast in vascular abdominopelvic and thigh distributions beyond MDCT angiography and DSA while preserving the ability to precisely assess severity of stenoses, using DSA as an accepted reference standard.
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Impact of Quantitatively Determined Native Thoracic Aortic Tortuosity on Endoleak Development After Thoracic Endovascular Aortic Repair. AJR Am J Roentgenol 2011; 197:W1140-6. [DOI: 10.2214/ajr.11.6819] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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Discriminant Analysis of Native Thoracic Aortic Curvature: Risk Prediction for Endoleak Formation After Thoracic Endovascular Aortic Repair. J Vasc Interv Radiol 2011; 22:974-979.e2. [DOI: 10.1016/j.jvir.2011.02.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 02/16/2011] [Accepted: 02/22/2011] [Indexed: 11/30/2022] Open
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Martin Rodriguez Z, Kenny P, Gaynor L. Improved characterisation of aortic tortuosity. Med Eng Phys 2011; 33:712-9. [DOI: 10.1016/j.medengphy.2011.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 11/04/2010] [Accepted: 01/15/2011] [Indexed: 11/28/2022]
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Zhou C, Chan HP, Chughtai A, Patel S, Hadjiiski LM, Wei J, Kazerooni EA. Automated coronary artery tree extraction in coronary CT angiography using a multiscale enhancement and dynamic balloon tracking (MSCAR-DBT) method. Comput Med Imaging Graph 2011; 36:1-10. [PMID: 21601422 DOI: 10.1016/j.compmedimag.2011.04.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 04/01/2011] [Accepted: 04/01/2011] [Indexed: 11/17/2022]
Abstract
RATIONAL AND OBJECTIVES To evaluate our prototype method for segmentation and tracking of the coronary arterial tree, which is the foundation for a computer-aided detection (CADe) system to be developed to assist radiologists in detecting non-calcified plaques in coronary CT angiography (cCTA) scans. MATERIALS AND METHODS The heart region was first extracted by a morphological operation and an adaptive thresholding method based on expectation-maximization (EM) estimation. The vascular structures within the heart region were enhanced and segmented using a multiscale coronary response (MSCAR) method that combined 3D multiscale filtering, analysis of the eigenvalues of Hessian matrices and EM estimation segmentation. After the segmentation of vascular structures, the coronary arteries were tracked by a 3D dynamic balloon tracking (DBT) method. The DBT method started at two manually identified seed points located at the origins of the left and right coronary arteries (LCA and RCA) for extraction of the arterial trees. The coronary arterial trees of a data set containing 20 ECG-gated contrast-enhanced cCTA scans were extracted by our MSCAR-DBT method and a clinical GE Advantage workstation. Two experienced thoracic radiologists visually examined the coronary arteries on the original cCTA scans and the rendered volume of segmented vessels to count the untracked false-negative (FN) segments and false positives (FPs) for both methods. RESULTS For the visible coronary arterial segments in the 20 cases, the radiologists identified that 25 segments were missed by our MSCAR-DBT method, ranging from 0 to 5 FN segments in individual cases, and that 55 artery segments were missed by the GE software, ranging from 0 to 7 FN segments in individual cases. 19 and 15 FPs were identified in our and the GE coronary trees, ranging from 0 to 4 FPs for both methods in individual cases, respectively. CONCLUSION The preliminary study demonstrates the feasibility of our MSCAR-DBT method for segmentation and tracking coronary artery trees. The results indicated that both our method and GE software can extract coronary artery trees reasonably well and the performance of our method is superior to that of GE software in this small data set. Further studies are underway to develop methods for improvement of the segmentation and tracking accuracy.
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Affiliation(s)
- Chuan Zhou
- Department of Radiology, University of Michigan, Ann Arbor 48109, USA.
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Bae KT. Intravenous contrast medium administration and scan timing at CT: considerations and approaches. Radiology 2010; 256:32-61. [PMID: 20574084 DOI: 10.1148/radiol.10090908] [Citation(s) in RCA: 646] [Impact Index Per Article: 46.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The continuing advances in computed tomographic (CT) technology in the past decades have provided ongoing opportunities to improve CT image quality and clinical practice and discover new clinical CT imaging applications. New CT technology, however, has introduced new challenges in clinical radiology practice. One of the challenges is with intravenous contrast medium administration and scan timing. In this article, contrast medium pharmacokinetics and patient, contrast medium, and CT scanning factors associated with contrast enhancement and scan timing are presented and discussed. Published data from clinical studies of contrast medium and physiology are reviewed and interpreted. Computer simulation data are analyzed to provide an in-depth analysis of various factors associated with contrast enhancement and scan timing. On the basis of basic principles and analysis of the factors, clinical considerations and modifications to protocol design that are necessary to optimize contrast enhancement for common clinical CT applications are proposed.
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Affiliation(s)
- Kyongtae T Bae
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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Aortic valves stenosis and regurgitation: assessment with dual source computed tomography. Int J Cardiovasc Imaging 2009; 25:591-600. [DOI: 10.1007/s10554-009-9456-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 03/23/2009] [Indexed: 10/20/2022]
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Hazirolan T, Turkbey B, Akpinar E, Canyigit M, Karcaaltincaba M, Peynircioglu B, Balkanci ZD, Akata D, Balkanci F. The impact of warmed intravenous contrast material on the bolus geometry of coronary CT angiography applications. Korean J Radiol 2009; 10:150-5. [PMID: 19270861 PMCID: PMC2651444 DOI: 10.3348/kjr.2009.10.2.150] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Accepted: 11/18/2008] [Indexed: 11/18/2022] Open
Abstract
Objective This study was designed to investigate the effect of administration of warmed contrast material (CM) on the bolus geometry and enhancement as depicted on coronary CT angiography. Materials and Methods A total of 64 patients (42 men, 22 women; mean age, 56 years) were randomly divided into two groups. Group 1 included 32 patients administered CM (Omnipaque [Iohexol] 350 mg I/ mL; Nycomed, Princeton, NJ) saline solutions kept in an incubator at a constant temperature (37℃). Group 2 included 32 patients administered the CM saline solutions kept at constant room temperature (24℃). Cardiac CT scans were performed with a dual source computed tomography (DSCT) scanner. For each group, region of interest curves were plotted inside the ascending aorta, main pulmonary artery and descending aorta on test bolus images. Using enhancement values, time/enhancement diagrams were produced for each vessel. On diagrams, basal Hounsfield unit (HU) values were subtracted from sequentially obtained values. A value of 100 HU was accepted as a cut-off value for the beginning of opacification. The time to peak, the time required to reach 100 HU opacification, maximum enhancement and duration of enhancement above 100 HU were noted. DSCT angiography studies were evaluated for coronary vessel enhancement. Results Maximum enhancement values in the ascending aorta, descending aorta and main pulmonary artery were significantly higher in group 1 subjects. In the ascending aorta, the median time required to reach 100 HU opacification during the test bolus analysis was significantly shorter for group 2 subjects than for group 1 subjects. In the ascending aorta, the descending aorta and main pulmonary artery, for group 1 subjects, the bolus geometry curve shifted to the left and upwards as compared with the bolus geometry curve for group 2 subjects. Conclusion The use of warmed CM yields higher enhancement values and a shorter time to reach maximum enhancement duration, resulting in a shift of the bolus geometry curve to the left that may provide optimized image quality.
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Affiliation(s)
- Tuncay Hazirolan
- Department of Radiology, Hacettepe University School of Medicine, Ankara, Turkey
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Chan HP, Hadjiiski L, Zhou C, Sahiner B. Computer-aided diagnosis of lung cancer and pulmonary embolism in computed tomography-a review. Acad Radiol 2008; 15:535-55. [PMID: 18423310 PMCID: PMC2800985 DOI: 10.1016/j.acra.2008.01.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 01/01/2008] [Accepted: 01/17/2008] [Indexed: 02/08/2023]
Abstract
Computer-aided detection (CADe) and computer-aided diagnosis (CADx) have been important areas of research in the last two decades. Significant progress has been made in the area of breast cancer detection, and CAD techniques are being developed in many other areas. Recent advances in multidetector row computed tomography have made it an increasingly common modality for imaging of lung diseases. A thoracic examination using thin-section computed tomography contains hundreds of images. Detection of lung cancer and pulmonary embolism on computed tomographic (CT) examinations are demanding tasks for radiologists because they have to search for abnormalities in a large number of images, and the lesions can be subtle. If successfully developed, CAD can be a useful second opinion to radiologists in thoracic CT interpretation. In this review, we summarize the studies that have been reported in these areas, discuss some challenges in the development of CAD, and identify areas that deserve particular attention in future research.
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Affiliation(s)
- Heang-Ping Chan
- Department of Radiology, Med Inn Building C477, 1500 East Medical Center Drive, The University of Michigan, Ann Arbor, MI 48109-5842, USA.
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Quantitative Analysis of Extracardiac Versus Intraatrial Fontan Anatomic Geometries. Ann Thorac Surg 2008; 85:810-7. [DOI: 10.1016/j.athoracsur.2007.11.082] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Revised: 11/27/2007] [Accepted: 11/28/2007] [Indexed: 11/22/2022]
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Zhou C, Chan HP, Sahiner B, Hadjiiski LM, Chughtai A, Patel S, Wei J, Ge J, Cascade PN, Kazerooni EA. Automatic multiscale enhancement and segmentation of pulmonary vessels in CT pulmonary angiography images for CAD applications. Med Phys 2007; 34:4567-77. [PMID: 18196782 PMCID: PMC2742232 DOI: 10.1118/1.2804558] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The authors are developing a computerized pulmonary vessel segmentation method for a computer-aided pulmonary embolism (PE) detection system on computed tomographic pulmonary angiography (CTPA) images. Because PE only occurs inside pulmonary arteries, an automatic and accurate segmentation of the pulmonary vessels in 3D CTPA images is an essential step for the PE CAD system. To segment the pulmonary vessels within the lung, the lung regions are first extracted using expectation-maximization (EM) analysis and morphological operations. The authors developed a 3D multiscale filtering technique to enhance the pulmonary vascular structures based on the analysis of eigenvalues of the Hessian matrix at multiple scales. A new response function of the filter was designed to enhance all vascular structures including the vessel bifurcations and suppress nonvessel structures such as the lymphoid tissues surrounding the vessels. An EM estimation is then used to segment the vascular structures by extracting the high response voxels at each scale. The vessel tree is finally reconstructed by integrating the segmented vessels at all scales based on a "connected component" analysis. Two CTPA cases containing PEs were used to evaluate the performance of the system. One of these two cases also contained pleural effusion disease. Two experienced thoracic radiologists provided the gold standard of pulmonary vessels including both arteries and veins by manually tracking the arterial tree and marking the center of the vessels using a computer graphical user interface. The accuracy of vessel tree segmentation was evaluated by the percentage of the "gold standard" vessel center points overlapping with the segmented vessels. The results show that 96.2% (2398/2494) and 96.3% (1910/1984) of the manually marked center points in the arteries overlapped with segmented vessels for the case without and with other lung diseases. For the manually marked center points in all vessels including arteries and veins, the segmentation accuracy are 97.0% (4546/4689) and 93.8% (4439/4732) for the cases without and with other lung diseases, respectively. Because of the lack of ground truth for the vessels, in addition to quantitative evaluation of the vessel segmentation performance, visual inspection was conducted to evaluate the segmentation. The results demonstrate that vessel segmentation using our method can extract the pulmonary vessels accurately and is not degraded by PE occlusion to the vessels in these test cases.
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Affiliation(s)
- Chuan Zhou
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, USA.
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22
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Engelke C, Schmidt S, Bakai A, Auer F, Marten K. Computer-assisted detection of pulmonary embolism: performance evaluation in consensus with experienced and inexperienced chest radiologists. Eur Radiol 2007; 18:298-307. [PMID: 17901958 DOI: 10.1007/s00330-007-0770-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 08/22/2007] [Accepted: 08/28/2007] [Indexed: 10/22/2022]
Abstract
The value of a computer-aided detection tool (CAD) as second reader in combination with experienced and inexperienced radiologists for the diagnosis of acute pulmonary embolism (PE) was assessed prospectively. Computed tomographic angiography (CTA) scans (64 x 0.6 mm collimation; 61.4 mm/rot table feed) of 56 patients (31 women, 34-89 years, mean = 66 years) with suspected PE were analysed by two experienced (R1, R2) and two inexperienced (R3, R4) radiologists for the presence and distribution of emboli using a five-point confidence rating, and by CAD. Informed consent was obtained from all patients. Results were compared with an independent reference standard. Inter-observer agreement was calculated by kappa, confidence assessed by ROC analysis. A total of 1,116 emboli [within mediastinal (n = 72), lobar (n = 133), segmental (n = 465) and subsegmental arteries (n = 455)] were included. CAD detected 343 emboli (sensitivity = 30.74%, correct-positive rate = 6.13/patient; false-positive rate = 4.1/patient). Inter-observer agreement was good (R1, R2: kappa = 0.84, 95% CI = 0.81-0.87; R3, R4: kappa = 0.79, 95% CI = 0.76-0.81). Extended inter-observer agreement was higher in mediastinal and lobar than in segmental and subsegmental arteries (kappa = 0.84-0.86 and kappa = 0.51-0.58 for mediastinal/lobar and segmental/subsegmental arteries, respectively P < 0.05). Agreement between experienced and inexperienced readers was improved by CAD (kappa = 0.60-0.62 and kappa = 0.69-0.72 before and after CAD consensus, respectively P < 0.05). The experienced outperformed the inexperienced readers (Az = 0.95, 0.93, 0.89 and 0.86 for R1-4, respectively, P < 0.05). CAD significantly improved overall performances of readers 3 and 4 (Az = 0.86 for R3, R4 and Az = 0.89 for R3, R4 with CAD, P < 0.05), by enhancing sensitivities in segmental/subsegmental arteries. CAD improved experienced readers' sensitivities in segmental/subsegmental arteries (sens. = 0.93 and 0.90 for R1, R2 before and 0.97 and 0.94 for R1, R2 after CAD consensus, P < 0.05), without significant improvement of their overall performances (P > 0.05). Particularly inexperienced readers benefit from consensus with CAD data, greatly improving detection of segmental and subsegmental emboli. This system is advocated as a second reader.
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Affiliation(s)
- Christoph Engelke
- Department of Radiology, University of Wuerzburg, 97080 Wuerzburg, Germany.
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Alkadhi H, Desbiolles L, Husmann L, Plass A, Leschka S, Scheffel H, Vachenauer R, Schepis T, Gaemperli O, Flohr TG, Genoni M, Marincek B, Jenni R, Kaufmann PA, Frauenfelder T. Aortic regurgitation: assessment with 64-section CT. Radiology 2007; 245:111-21. [PMID: 17717329 DOI: 10.1148/radiol.2451061523] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively evaluate diagnostic accuracy of 64-section computed tomography (CT) for evaluation of aortic regurgitation (AR), with transthoracic echocardiography (TTE) as reference. MATERIALS AND METHODS The institutional review board approved this study; written informed consent was obtained. Thirty patients (23 men, seven women; mean age, 56.6 years) with AR underwent TTE and retrospective electrocardiographically gated 64-section CT. CT data sets were reconstructed in 5% steps from 40% to 90% of R-R interval for analysis. Maximum regurgitant orifice area (ROA) in diastole was planimetrically measured with CT, and measurements were compared with semiquantitative classification with TTE (Spearman rank order correlation coefficients). Receiver operating characteristic (ROC) curves were calculated for differentiation between degrees of AR with ROA measurements. Dimensions of the aortic root and left ventricular parameters were compared (Pearson correlation analysis). RESULTS A significant correlation was observed between CT planimetric size of ROA (mean, 62 mm2+/-63 [standard deviation]; range, 6-224 mm2) and TTE classification of mild, moderate, and severe AR (r=0.84, P<.001). With ROC analysis, discrimination between degrees of AR with CT was highly accurate when cutoff ROAs (25 mm2 and 75 mm2) were used. A significant correlation was observed between methods in dimensions of aortic annulus (mean, 29.0 mm+/-4.6), sinus of Valsalva (mean, 38.3 mm+/-8.6), and ascending aorta (mean, 37.2 mm+/-8.0); mean values were 27.4 mm+/-4.9 (r=0.76, P<.001), 37.7 mm+/-8.6 (r=0.94, P<.001), and 38.2 mm+/-7.9 (r=0.96, P<.001), respectively. Mean end-systolic volume (67 mL+/-38), end-diastolic volume (149 mL+/-48), and ejection fraction (57%+/-13) at CT correlated well with mean results at TTE (65 mL+/-36 [r=0.96, P<.001], 140 mL+/-48 [r=0.91, P<.001], 56%+/-13 [r=0.98, P<.001], respectively). CONCLUSION Results of assessment of AR with 64-section CT are similar to those with TTE.
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Affiliation(s)
- Hatem Alkadhi
- Institute of Diagnostic Radiology, Clinic for Cardiovascular Surgery, and Cardiovascular Center, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland.
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24
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Khan AM, Lad T, Jacobs SJ. Computed tomography aortic three-dimensional reconstruction: An invaluable tool for diagnosis of juxtarenal abdominal aortic aneurysm. JOURNAL OF VASCULAR NURSING 2006; 24:133-6. [PMID: 17141132 DOI: 10.1016/j.jvn.2006.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 06/23/2006] [Accepted: 08/17/2006] [Indexed: 11/27/2022]
Abstract
Accurate mapping of the aortic aneurysm in relation to the renal artery is pivotal in the success of abdominal aortic aneurysm repair. Currently, contrast computed tomography (CT), a method of combining both angiography and CT scan, is being used in the evaluation and diagnosis of abdominal aortic aneurysm. We report a series of cases in which contrast CT alone gave us misleading information on the true nature of the aneurysm in relation to the renal arteries. We conclude that the three-dimensional spiral CT reconstructed model provides better morphologic information for clinical decision-making than contrast CT alone.
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Affiliation(s)
- Amir M Khan
- Department of Vascular Surgery, King George Hospital, Essex, United Kingdom.
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Lu D, Bai E, Liu J, Yu H, Wei Y, Cai Z, Sharafuddin MJ, Golzarian J, Stolpen A, Saba O, Vannier M, Wang G. Projection-based bolus detection for computed tomographic angiography. J Comput Assist Tomogr 2006; 30:846-9. [PMID: 16954941 DOI: 10.1097/01.rct.0000230000.08027.ad] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Computed tomographic (CT) angiography is important for imaging studies on cardiovascular structures, peripheral vessels, and solid organs. In practice, a CT angiography scan is triggered by the bolus arrival at a prespecified anatomical location, which is determined using CT fluoroscopy. In this article, we propose a projection-based method adapted from the Grangeat formula to detect the bolus arrival. Then, we evaluate our new method in numerical and animal studies. Our results indicate that this method allows significantly better temporal resolution and is computationally more efficient, as compared with the image-based methods.
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Affiliation(s)
- Donghui Lu
- CT/Micro-CT Laboratory, Department of Radiology, University of Iowa, Iowa City, IA, USA.
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26
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Kubo S, Tadamura E, Yamamuro M, Hosokawa R, Kimura T, Kita T, Komeda M, Togashi K. Thoracoabdominal-Aortoiliac MDCT Angiography Using Reduced Dose of Contrast Material. AJR Am J Roentgenol 2006; 187:548-54. [PMID: 16861562 DOI: 10.2214/ajr.05.0309] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of our study was to compare the image quality of MDCT angiography studies obtained by injection of low doses of contrast medium with saline flush versus conventional doses of contrast medium. MATERIALS AND METHODS Seventy-one patients with pre- or postoperative aortic aneurysms underwent MDCT angiography throughout the thoracoabdominal-aortoiliac system using an 8-MDCT scanner. In 37 patients, 100 mL of contrast medium was injected at a flow rate of 3.0 mL/s (hereafter referred to as the 100-mL group). In 34 patients, 50 mL of contrast medium followed by a 20-mL saline flush was injected at a flow rate of 2.5 mL/s (the 50-mL group). For each group, quantitative analysis involved calculating the mean aortoiliac enhancement, plateau deviation, and contrast enhancement in the pulmonary trunk and superior vena cava (SVC). Qualitative analysis involved assessing the 3D postprocessing images. RESULTS Significant differences between the groups in mean aortoiliac enhancement (100-mL group vs 50-mL group, 337 +/- 6 H vs 319 +/- 5 H, p < 0.0001) and mean plateau deviation (51 +/- 4 H vs 58 +/- 4 H, p < 0.0001) were found. However, adequate arterial enhancement (>or= 200 H) was observed in 31 of 34 patients in the 50-mL group and uniform aortoiliac enhancement (< 50 H) was seen in 26 patients. Visual analysis showed no difference in contrast material magnitude and homogeneity between the groups. Furthermore, in the 50-mL group, the thoracic aorta was more clearly visualized because of a reduction in the opacity of the main pulmonary artery and SVC. CONCLUSION In our experience, administration of 50 mL of contrast medium followed by a 20-mL saline flush produces thoracoabdominal-aortoiliac MDCT angiographic examinations of effective quality in most cases.
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Affiliation(s)
- Shigeto Kubo
- Department of Nuclear Medicine and Diagnostic Imaging, Kyoto University Graduate School of Medicine, Kyoto, Japan
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27
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Honda M, Sugimoto H, Obuchi M, Narisawa T. Preliminary examination to determine the suitable contrast material injection protocol for CT angiography of the pelvis and lower extremities with a multidetector row helical scanner. ACTA ACUST UNITED AC 2006; 24:239-46. [PMID: 16958396 DOI: 10.1007/s11604-005-1473-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Accepted: 12/01/2005] [Indexed: 11/30/2022]
Abstract
PURPOSE The aim of this study was to determine the best of three protocols for the depiction of arteries in the pelvis and lower extremities by computed tomographic angiography (CTA) with a multidetector row helical scanner. MATERIALS AND METHODS CTA was performed in five asymptomatic volunteers using a four-channel multidetector row helical scanner. Low-osmolar iodinated contrast material was injected at the flow rate of 3 ml/s using three protocols: 100 ml of 300 mg I/ml, 150 ml of 300 mg I/ml, and 100 ml of 350 mg I/ml. The CT number of opacified blood was measured at six levels. Three doctors independently assessed the degree of depiction of arteries on CTA images without knowing the protocol using a 3-point scale. RESULTS CT numbers at the level of the popliteal artery on the protocol of 150 ml of 300 mg I/ml were significantly greater than the others. The mean score for the depiction of trifurcation on the protocol of 150 ml of 300 mg I/ml was significantly greater than those in the others. CONCLUSION The protocol of 150 ml of 300 mg I/ml was the best for depicting arteries in the pelvis and lower extremities by CTA.
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Affiliation(s)
- Minoru Honda
- Department of Radiology, Showa University Hospital, 1-5-8 Hatanodai, Tokyo, Japan.
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28
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Gupta R, Jones SE, Mooyaart EAQ, Pomerantz SR. Computed Tomographic Angiography in Stroke Imaging: Fundamental Principles, Pathologic Findings, and Common Pitfalls. Semin Ultrasound CT MR 2006; 27:221-42. [PMID: 16808221 DOI: 10.1053/j.sult.2006.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The development of multidetector row computed tomography (MDCT) now permits visualization of the entire vascular tree that is relevant for the management of stroke within 15 seconds. Advances in MDCT have brought computed tomography angiography (CTA) to the frontline in evaluation of stroke. CTA is a rapid and noninvasive modality for evaluating the neurovasculature. This article describes the role of CTA in the management of stroke. Fundamentals of contrast delivery, common pathologic findings, artifacts, and pitfalls in CTA interpretation are discussed.
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Affiliation(s)
- Rajiv Gupta
- Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, USA.
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29
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Keller D, Wildermuth S, Boehm T, Boskamp T, Mayer D, Schuster HL, Marincek B, Alkadhi H. CT angiography of peripheral arterial bypass grafts: Accuracy and time-effectiveness of quantitative image analysis with an automated software tool. Acad Radiol 2006; 13:610-20. [PMID: 16627202 DOI: 10.1016/j.acra.2006.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 01/11/2006] [Accepted: 01/11/2006] [Indexed: 11/27/2022]
Abstract
RATIONALE AND OBJECTIVES Qualitative analysis of computed tomography (CT) angiography data often is limited by intra- and interobserver variability. The purpose of this study was to evaluate the time-effectiveness and accuracy of a quantitative CT angiography data analysis using automated software in comparison with qualitative axial and coronal CT image reading in patients with peripheral bypass grafts. MATERIALS AND METHODS Twenty-eight patients with 33 saphenous bypass grafts underwent 4-channel (n = 21) and 16-channel (n = 7) CT angiography. Two readers evaluated in consensus the CT data qualitatively on axial and coronal reconstructions and with the software regarding the presence of graft stenoses, aneurysmal changes, and arteriovenous fistulas. The time for data analysis was taken and the accuracy was compared with the results from digital subtraction angiography (DSA). RESULTS No significant difference was present between data analysis time using axial and coronal CT images (4.9 +/- 1.5 minutes) and when using the software tool (5.5 +/- 1.4 minutes). Good (kappa = 0.652) to excellent (kappa = 1.000) intermodality agreement was present between qualitative and quantitative CT analysis regarding graft-related abnormalities. Sensitivity and specificity for diagnosing stenoses, aneurysms, and fistula did not differ significantly (P > .025) between qualitative CT image reading and the automated software tool. CONCLUSIONS CT angiography analysis of peripheral bypass grafts using an automated software tool is similar regarding time-effectiveness and accuracy when compared with qualitative CT data analysis on axial and coronal images. It may assist in determining the significance of an abnormality and can yield objective morphometric data of vessel calibers.
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Affiliation(s)
- Denise Keller
- Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich
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30
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Maddah M, Soltanian-Zadeh H, Afzali-Kusha A, Shahrokni A, Zhang ZG. Three-dimensional analysis of complex branching vessels in confocal microscopy images. Comput Med Imaging Graph 2005; 29:487-98. [PMID: 15996853 DOI: 10.1016/j.compmedimag.2005.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 03/12/2005] [Accepted: 03/12/2005] [Indexed: 10/25/2022]
Abstract
The characteristic of confocal microscopy (CM) vascular data is that it contains many tiny vessels with branching and complex structure. In this work, an automated method for quantitative analysis and reconstruction of cerebral vessels from CM images is presented in which the extracted centerline of the vessels plays the key role. To assess the efficiency and accuracy of different centerline extraction methods, a comparison among three fully automated approaches is given. The centerline extraction methods studied in this work are a snake model, a path planning approach, and a distance transform-based method. To evaluate the accuracy of the quantitative parameters of vessels such as length and diameter, we apply the method to synthetic data. These results indicate that the snake model and the path planning method are more accurate in extracting the quantitative parameters. The efficiency of the approach in clinical applications is then confirmed by applying the method to real CM images. All three methods investigated in this work are accurate enough to correctly distinguish between normal and stroke brain data, while the snake model is the fastest for clinical applications. In addition, three-dimensional visualization, reconstruction, and characterization of CM vascular images of rat brains are presented.
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Affiliation(s)
- Mahnaz Maddah
- Control and Intelligent Processing Center of Excellence, Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
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31
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Zhou C, Chan HP, Patel S, Cascade PN, Sahiner B, Hadjiiski LM, Kazerooni EA. Preliminary investigation of computer-aided detection of pulmonary embolism in three-dimensional computed tomography pulmonary angiography images. Acad Radiol 2005; 12:782-92. [PMID: 15935977 PMCID: PMC2784697 DOI: 10.1016/j.acra.2005.01.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Revised: 12/11/2004] [Accepted: 01/12/2005] [Indexed: 11/27/2022]
Abstract
RATIONALE AND OBJECTIVES We sought to develop a computer-aided diagnosis (CAD) system for assisting radiologists in the detection of pulmonary embolism (PE) on computed tomography pulmonary angiographic (CTPA) images. MATERIALS AND METHODS An adaptive three-dimensional (3D) voxel clustering method was developed based on expectation-maximization (EM) analysis to extract vessels from their surrounding tissues. Using a connected component analysis, the vessel tree was reconstructed by tracking the vessel and its branches in 3D space. The tracked vessels were prescreened for suspicious PE areas using a second EM analysis. A rule-based false-positive (FP) reduction method was designed to detect true PE based on the features of PE and vessels. In this preliminary study, 14 patients with positive CTPA for PE were studied. CT scans were performed at 1.25-mm collimation using a GE LightSpeed CT scanner; eight of these patients also had extensive lung parenchymal or pleural disease. One hundred sixty-three emboli were identified by two experienced thoracic radiologists. The emboli identified by the radiologists were used as the "gold standard." For each embolus, the percent diameter occlusion (clot) and conspicuity of embolus (rating of 1 to 5, with 5 being the most conspicuous) were visually estimated. One hundred one emboli were identified in the six patients without lung diseases; 57 were proximal to the subsegmental and 44 were subsegmental. For the eight patients with lung diseases, 62 emboli were identified, of which 37 were proximal to the subsegmental and 25 were subsegmental. A computer-detected volume was counted as true-positive when it overlapped with an embolus volume identified by the radiologists. RESULTS In the cases without lung diseases, if the PE had a conspicuity of >2 and only partially (20%-80%) occluded the vessel, our method detected 92.0% of proximal emboli and 77.8% of subsegmental emboli, with an average of 18.3 FPs/case. In the cases containing extensive lung disease, 66.7% and 40.0% of the PEs were detected with an average of 11.4 FPs/case under the same conditions. For the 14 PE cases, 13 of them were diagnosed as positive PE cases (case sensitivity was 92.9%). CONCLUSION This preliminary study indicates that our automated method is a promising approach to CAD of PE on CTPA. Further study is under way to collect a larger data set and to improve the detection accuracy for PE, especially those with <20% or >80% occlusion, and for very subtle PE. A fully developed CAD system is expected to provide a useful aid for PE detection on CTPA.
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Affiliation(s)
- Chuan Zhou
- Department of Radiology, University of Michigan, Ann Arbor, CGC B2103, 1500 E. Medical Center Drive, Ann Arbor, MI 48109, USA.
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Hyodoh H, Katagiri Y, Sakai T, Hyodoh K, Akiba H, Hareyama M. Creation of individual ideally shaped stents using multi-slice CT: in vitro results from the semi-automatic virtual stent (SAVS) designer. Eur Radiol 2005; 15:1623-8. [PMID: 15761717 DOI: 10.1007/s00330-004-2587-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Revised: 11/01/2004] [Accepted: 11/08/2004] [Indexed: 10/25/2022]
Abstract
To plan stent-grafting for thoracic aortic aneurysm with complicated morphology, we created a virtual stent-grafting program [Semi Automatic Virtual Stent (SAVS) designer] using three-dimensional CT data. The usefulness of the SAVS designer was evaluated by measurement of transformed anatomical and straight stents. Curved model images (source, multi-planer reconstruction and volume rendering) were created, and a hollow virtual stent was produced by the SAVS designer. A straight Nitinol stent was transformed to match the curved configuration of the virtual stent. The accuracy of the anatomical stent was evaluated by experimental strain phantom studies in comparison with the straight stent. Mean separation length was 0 mm in the anatomical stent [22 mm outer diameter (OD)] and 5 mm in the straight stent (22 mm OD). The straight stent strain voltage was four times that of the anatomical stent at the stent end. The anatomical stent is useful because it fits the curved structure of the aorta and reduces the strain force compared to the straight stent. The SAVS designer can help to design and produce the anatomical stent.
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Affiliation(s)
- Hideki Hyodoh
- Department of Radiology, Sapporo Medical University, S-1 W-16 Chuo-ku, Sapporo, 060-8543, Japan.
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33
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Hellinger JC. Endovascular Repair of Thoracic and Abdominal Aortic Aneurysms: Pre- and Postprocedural Imaging. Tech Vasc Interv Radiol 2005; 8:2-15. [PMID: 16098932 DOI: 10.1053/j.tvir.2005.05.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Endovascular repair of thoracic and abdominal aortic aneurysms is a safe alternative to conventional open surgical repair. Clinical success, however, is highly dependent on patient selection. Diagnostic vascular imaging has an essential role for this selection process. Following endovascular aneurysm repair (EVAR), patients require long-term surveillance and again vascular imaging serves an integral function. This article reviews EVAR selection criteria and post-EVAR assessment and then discusses the imaging modalities used to evaluate these patients, namely multi-detector-row computed tomographic angiography, magnetic resonance imaging/angiography, duplex ultrasonography, and catheter angiography.
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Affiliation(s)
- Jeffrey C Hellinger
- Department of Radiology, Stanford University Medical Center, Stanford, CA 94305, USA.
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Abstract
PURPOSE OF REVIEW The dilated aortic root is often completely asymptomatic and found incidentally on routine imaging studies such as chest radiograph, echocardiography, chest computed tomography, or magnetic resonance imaging. The dilated aortic root may be associated with underlying aortic valve abnormalities as seen with bicuspid aortic valve. It may also lead to the awareness of important underlying connective tissue disorders like the Marfan syndrome. It is imperative that the dilated aortic root be observed carefully over time with serial imaging studies and that timely resection of the aneurysm be carried out before catastrophic complications such as aortic dissection, aortic rupture, or congestive heart failure from aortic insufficiency occur. RECENT FINDINGS In recent years, the advent of molecular genetics has heightened awareness of familial aortic disease such as the Marfan syndrome, bicuspid aortic valve disease, and hereditary aortic aneurysm and dissection. In addition to hypertension and inflammatory aortic disease, these hereditary aortopathies are important to consider in the evaluation of patients with a dilated aorta and have implications for screening of the relatives of the patient with aortic aneurysm. SUMMARY Because there is often uncertainty regarding the dilated aortic root, this review will summarize the approach to diagnosis, evaluation, and management of aortic root aneurysms. Clinical features, diagnostic approaches, screening of relatives, and long term follow-up will be highlighted.
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Affiliation(s)
- John K Boyer
- Department of Medicine, and the Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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35
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Neri E, Bargellini I, Rieger M, Giachetti A, Vignali C, Tuveri M, Jaschke W, Bartolozzi C. Abdominal aortic aneurysms: virtual imaging and analysis through a remote web server. Eur Radiol 2004; 15:348-52. [PMID: 15503043 DOI: 10.1007/s00330-004-2500-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 08/03/2004] [Accepted: 08/23/2004] [Indexed: 10/26/2022]
Abstract
The study describes the application of a web-based software in the planning of the endovascular treatment of abdominal aortic aneurysms (AAA). The software has been developed in the framework of a 2-year research project called Aneurysm QUAntification Through an Internet Collaborative System (AQUATICS); it allows to manage remotely Virtual Reality Modeling Language (VRML) models of the abdominal aorta, derived from multirow computed tomography angiography (CTA) data sets, and to obtain measurements of diameters, angles and centerline lengths. To test the reliability of measurements, two radiologists performed a detailed analysis of multiple 3D models generated from a synthetic phantom, mimicking an AAA. The system was tested on 30 patients with AAA; CTA data sets were mailed and the time required for segmentation and measurement were collected for each case. The Bland-Altman plot analysis showed that the mean intra- and inter-observer differences in measures on phantoms were clinically acceptable. The mean time required for segmentation was 1 h (range 45-120 min). The mean time required for measurements on the web was 7 min (range 4-11 min). The AQUATICS web server may provide a rapid, standardized and accurate tool for the evaluation of AAA prior to the endovascular treatment.
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Affiliation(s)
- Emanuele Neri
- Diagnostic and Interventional Radiology, Department of Oncology, Transplants, and Advanced Technologies in Medicine, University of Pisa, Via Roma 67, 56100, Pisa, Italy.
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Diehm N, Herrmann P, Dinkel HP. Multidetector CT Angiography Versus Digital Subtraction Angiography for Aortoiliac Length Measurements Prior to Endovascular AAA Repair. J Endovasc Ther 2004; 11:527-34. [PMID: 15482025 DOI: 10.1583/03-1172.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
PURPOSE To assess observer variation between calibrated-catheter digital subtraction angiography (DSA) and software-enhanced multidetector computed tomography angiography (CTA) in measuring vessel length prior to endovascular aortic aneurysm repair (EVAR). METHODS Thirty patients (25 men; mean age 65 years, range 61-85) scheduled for EVAR underwent CTA in 4x2-mm collimation using advanced vessel analysis software. CTA measurements were performed twice by 2 blinded readers in random order with at least a 4-week interval between readings. Nine patients were found unsuitable for endovascular repair after the CTA, so DSA was performed in 21 patients for morphometric evaluation of the abdominal aorta and the iliac arteries. The following segments were measured: H1 (aneurysm neck), H2 (lower renal artery to distal aspect of the aneurysm), H3 (lower renal artery to aortic bifurcation), and H4a/H4b (lower renal artery to iliac bifurcations). Length measurements on DSA were made by (1) following the catheter path in the aortic lumen and (2) dividing tortuous vessel anatomy into segments and measuring each segment along an idealized centerline. Addition of the various segments allowed comparison with data obtained from CTA measurements. RESULTS CTA was performed with good intraobserver agreement for all length parameters except H3 in reader 2 (p<0.05). While good interobserver agreement was demonstrated for CTA over long aortoiliac distances (H4a, H4b), higher interobserver agreement was obtained with DSA for shorter segments (H1, H2). Considerable differences were observed between CTA and DSA for the lengths H2 and H4b. CONCLUSIONS CTA produces better intra and interobserver correlations in measuring vessel length than DSA. It has the potential to replace DSA as an imaging method before EVAR.
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Affiliation(s)
- Nicolas Diehm
- Institute of Diagnostic Radiology, Department of Radiology, Inselspital, University Hospital of Bern, Switzerland
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Sun Z, Gallagher E. Multislice CT Virtual Intravascular Endoscopy for Abdominal Aortic Aneurysm Stent Grafts. J Vasc Interv Radiol 2004; 15:961-70. [PMID: 15361564 DOI: 10.1097/01.rvi.0000140936.45313.ee] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate the optimal scanning protocols of multislice computed tomographic (CT) angiography in aortic stent graft placement observed on virtual intravascular endoscopy (VIE). MATERIALS AND METHODS A human aorta phantom was built with a commercial aortic stent graft placed in situ. The phantom was housed in a perspex container and filled with contrast medium with CT attenuation similar to that used in the patient's abdominal scanning. CT was performed with a four-slice multislice CT scanner with section thickness of 1.3 mm, 2 mm, and 3.2 mm, pitch of 0.75, 1, and 1.5, and reconstruction interval of 50% overlap and no overlap. Stair-step artifacts were quantified by measuring the SD of signal intensity on surfaced shaded VIE images in three different locations: superior mesenteric artery (SMA), renal ostium, and aortic aneurysm. RESULTS Image quality of VIE images was independent of section thickness and pitch values in the level of renal ostium and aortic aneurysm (P >.05), whereas it was determined by the section thickness and pitch in the level of SMA (P <.05). Aortic branch origin became irregular or distorted when section thickness increased to 3.2 mm or pitch reached 1.5. CONCLUSION A scanning protocol of section thickness of 2 mm, pitch 1, and reconstruction interval of 1 mm is recommended in aortic stent graft placement because it allows fewer stair-step artifacts and better visualization of the aortic stent wires observed on VIE.
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Affiliation(s)
- Zhonghua Sun
- School of Applied Medical Sciences and Sports Studies, University of Ulster, Shore Road, Newtownabbey, BT37 0QB, Northern Ireland, United Kingdom.
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Suri JS, Liu K, Reden L, Laxminarayan S. A review on MR vascular image processing algorithms: acquisition and prefiltering: part I. ACTA ACUST UNITED AC 2004; 6:324-37. [PMID: 15224847 DOI: 10.1109/titb.2002.804139] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vascular segmentation has recently been given much attention. This review paper has two parts. Part I focuses on the physics of magnetic resonance angiography (MRA) generation and prefiltering techniques applied to MRA data sets. Part II of the review focuses on the vessel segmentation algorithms. The first section of this paper introduces the five different sets of receive coils used with the MRI system for magnetic resonance angiography data acquisition. This section then presents the five different types of the most popular data acquisition techniques: time-of-flight (TOF), phase-contrast, contrast-enhanced, black-blood, T2-weighted, and T2*-weighted, along with their pros and cons. Section II of this paper focuses on prefiltering algorithms for MRA data sets. This is necessary for removing the background nonvascular structures in the MRA data sets. Finally, the paper concludes with a clinical discussion on the challenges and the future of the data acquisition and the automated filtering algorithms.
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Affiliation(s)
- Jasjit S Suri
- Philips Medical Systems, Inc., Cleveland, OH 44143, USA
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Boll DT, Lewin JS, Fleiter TR, Duerk JL, Merkle EM. Multidetector CT angiography of arterial inflow and runoff in the lower extremities: a challenge in data acquisition and evaluation. J Endovasc Ther 2004; 11:144-51. [PMID: 15056024 DOI: 10.1583/03-1098.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
PURPOSE To show the feasibility of acquiring homogenous 3-dimensional datasets with high temporal and spatial resolution from computed tomographic angiographic (CTA) scans of the lower extremities and to assess automated vessel-tracking techniques for vascular evaluation. METHODS Eighteen men (mean age 67.0 years, range 43-83) with aneurysmal or occlusive vascular diseases underwent contrast-enhanced CTA of the lower limb arteries utilizing a 16-row CT imager. Curved multiplanar reformations were generated by manual selection of vessel centerlines in the infrarenal aorta and the arterial vasculature in the pelvis, thigh, and calf based on volume-rendering techniques. For each vessel, opacification and depiction were quantitatively evaluated. The manually segmented images were compared to datasets processed with automated vessel-tracking strategies by 5 radiologists, who evaluated diagnostic reliability and image quality. A Differential Receiver Operating Characteristic (DROC) analysis was performed. RESULTS An increase in the temporal and spatial resolution led to acquisition of high quality CTA datasets. Significant homogeneity of the vascular contrast-to-noise ratios was achieved in the pelvic (coefficient of variance 1.5% to 10.1%), thigh (0.1% to 9.4%), and calf (3.3% to 19.2%) vessels. The assessment of vascular delineation revealed full-width-at-half-maximum contrast values of 96.4%, 95.5%, and 111.3% in the pelvis, thigh, and calf, respectively. Observers were not able to distinguish between manual and automated vascular segmentation, as represented by a 0.56 value for the area under the DROC curve. CONCLUSIONS High-resolution CTA lower extremity datasets were acquired successfully, presenting vascular signal intensities of high homogeneity suitable for automated vessel-tracking techniques. Automated 3D visualization tools produced reliable, reproducible, and time-efficient centerline extractions that were comparable to manually defined centerlines.
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Affiliation(s)
- Daniel T Boll
- Department of Radiology, Case Western Reserve University, University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, OH 4410-106, USA
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Bae KT, Tran HQ, Heiken JP. Uniform vascular contrast enhancement and reduced contrast medium volume achieved by using exponentially decelerated contrast material injection method. Radiology 2004; 231:732-6. [PMID: 15163812 DOI: 10.1148/radiol.2313030497] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To investigate in computed tomographic (CT) angiography whether an exponentially decelerated contrast medium injection, as compared with a standard constant-rate injection, can facilitate uniform vascular contrast enhancement with a reduced contrast material volume. MATERIALS AND METHODS CT angiography of the abdominal aorta was performed in 46 subjects by using an exponentially decelerated injection method: 134 mL of contrast medium was injected for 40 seconds, starting at 4.0 mL/sec and decreasing exponentially to 2.7 mL/sec by the end of the injection. Twenty-one of these subjects also underwent CT angiography with a constant-rate injection: 160 mL of contrast medium was injected for 40 seconds at a constant rate of 4 mL/sec. Time-enhancement curves and the magnitude of peak vascular enhancement were measured. Enhancement uniformity was evaluated by using three indexes: (a) duration of contrast enhancement achieved within 80% of the peak (80% DCE), (b) SD of the normalized contrast enhancement (SDNCE) measured from the beginning of spiral CT scanning to the time when the enhancement decreased to a level lower than the beginning level, and (c) slope of the enhancement curve calculated by using linear regression analysis. RESULTS Exponentially decelerated injection resulted in more uniform enhancement. Mean values generated by using exponentially decelerated versus constant-rate injection in 21 paired comparisons were, respectively, 30.8 seconds +/- 5.0 versus 22.6 seconds +/- 7.6 for 80% DCE, 0.052 +/- 0.017 versus 0.086 +/- 0.031 for SDNCE, and 0.47 HU/sec +/- 0.70 versus 2.27 HU/sec +/- 0.87 for slope (P <.001 for all indexes). Compared with the peak enhancement resulting from the constant-rate injection, that resulting from the exponentially decelerated injection was reduced by a mean of 17.2% +/- 10.0. CONCLUSION Uniform vascular contrast enhancement and reduced contrast medium volume, which are desirable in CT angiography, can be achieved with exponentially decelerated injection.
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Affiliation(s)
- Kyongtae T Bae
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Box 8131, St Louis, MO 63110, USA.
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Tsai CL, Stewart CV, Tanenbaum HL, Roysam B. Model-Based Method for Improving the Accuracy and Repeatability of Estimating Vascular Bifurcations and Crossovers From Retinal Fundus Images. ACTA ACUST UNITED AC 2004; 8:122-30. [PMID: 15217257 DOI: 10.1109/titb.2004.826733] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A model-based algorithm, termed exclusion region and position refinement (ERPR), is presented for improving the accuracy and repeatability of estimating the locations where vascular structures branch and cross over, in the context of human retinal images. The goal is two fold. First, accurate morphometry of branching and crossover points (landmarks) in neuronal/vascular structure is important to several areas of biology and medicine. Second, these points are valuable as landmarks for image registration, so improved accuracy and repeatability in estimating their locations and signatures leads to more reliable image registration for applications such as change detection and mosaicing. The ERPR algorithm is shown to reduce the median location error from 2.04 pixels down to 1.1 pixels, while improving the median spread (a measure of repeatability) from 2.09 pixels down to 1.05 pixels. Errors in estimating vessel orientations were similarly reduced from 7.2 degrees down to 3.8 degrees.
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de Bruijne M, van Ginneken B, Viergever MA, Niessen WJ. Interactive segmentation of abdominal aortic aneurysms in CTA images. Med Image Anal 2004; 8:127-38. [PMID: 15063862 DOI: 10.1016/j.media.2004.01.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2003] [Accepted: 12/12/2003] [Indexed: 12/21/2022]
Abstract
A model-based approach to interactive segmentation of abdominal aortic aneurysms from CTA data is presented. After manual delineation of the aneurysm sac in the first slice, the method automatically detects the contour in subsequent slices, using the result from the previous slice as a reference. If an obtained contour is not sufficiently accurate, the user can intervene and provide an additional manual reference contour. The method is inspired by the active shape model (ASM) segmentation scheme (), in which a statistical shape model, derived from corresponding landmark points in manually labeled training images, is fitted to the image in an iterative manner. In our method, a shape model of the contours in two adjacent image slices is progressively fitted to the entire volume. The contour obtained in one slice thus constrains the possible shapes in the next slice. The optimal fit is determined on the basis of multi-resolution gray level models constructed from gray value patches sampled around each landmark. We propose to use the similarity of adjacent image slices for this gray level model, and compare these to single-slice features that are more generally used with ASM. The performance of various image features is evaluated in leave-one-out experiments on 23 data sets. Features that use the similarity of adjacent image slices outperform measures based on single-slice features in all cases. The average number of slices in our datasets is 51, while on average eight manual initializations are required, which decreases operator segmentation time by a factor of 6.
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Affiliation(s)
- Marleen de Bruijne
- Image Sciences Institute, University Medical Center Utrecht, E01.335, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
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Stueckle CA, Haegele KF, Jendreck M, Zipser MC, Kirchner J, Kickuth R, Liermann D. Multislice computed tomography angiography of the abdominal arteries: Comparison between computed tomography angiography and digital subtraction angiography findings in 52 cases. ACTA ACUST UNITED AC 2004; 48:142-7. [PMID: 15230747 DOI: 10.1111/j.1440-1673.2004.01275.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Since the introduction of multislice CT scanners, CT angiography (CTA) has become a powerful tool for imaging the vascular system. We compare conventional angiography to CTA in the diagnosis of morphological changes in the abdominal aorta and its branches. A retrospective analysis of 52 patients who underwent both multislice CT angiography (MSCTA) and digital subtraction angiography before surgical treatment is presented. All CT examinations were performed after administration of 100 mL contrast medium with a collimation of 4 x 1 mm and a pitch of 7. A standardized evaluation of the axial, multiplanar and 3D reconstructions was performed by two experienced radiologists. Stenoses were classified as high-grade and low-grade, and aneurysms, occlusions and arteriosclerosis were evaluated. The CTA findings were compared with conventional angiography. All aneurysms, occlusions, stenoses and calcifications were diagnosed correctly by CTA in axial and multiplanar projections (sensitivity 1.0; specificity 1.0). The degree of stenosis was overestimated in three cases when using axial projections. Three-dimensional volume-rendered CTA showed a sensitivity of 0.91 for aneurysms, 0.82 for stenoses, 0.75 for occlusions and 0.77 for calcifications. The specificity was 1.0 in all cases. Multislice CT angiography seems to be similar to conventional digital subtraction angiography for abdominal vessels if multiplanar projections are used.
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Affiliation(s)
- Christoph A Stueckle
- Department of Radiology and Nuclear Medicine, Marienhospital Herne, University Hospital of Ruhr-University-Bochum, Herne, Germany.
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Suzuki S, Furui S, Kaminaga T, Yamauchi T. Measurement of Vascular Diameter In Vitro by Automated Software for CT Angiography:Effects of Inner Diameter, Density of Contrast Medium, and Convolution Kernel. AJR Am J Roentgenol 2004; 182:1313-7. [PMID: 15100138 DOI: 10.2214/ajr.182.5.1821313] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE This investigation was performed to evaluate the accuracy of diameter measurement of vessels in vitro by automated software for CT angiography. MATERIALS AND METHODS Vascular models with three inner diameters ( approximately 3, 4, and 6 mm) filled with contrast medium of three different densities ( approximately 460, 350, and 210 H) were scanned with helical CT. Five convolution kernels (soft, standard, detail, bone, and lung) were used. We evaluated the measurement error, defined as the difference between the diameter measured by the automated software and the true inner diameter of the vascular model. Statistical analysis involved three-way analysis of variance with repeated measures. RESULTS Significant differences occurred in measurement error among the three vascular model inner diameters, among the three densities of intravascular contrast medium, and among the five convolution kernels (p < 0.01). In all the convolution kernels except lung, measurement errors progressively decreased with higher densities of intravascular contrast medium (p < 0.01). In vascular models filled with contrast medium of 350 H, measurement errors were significantly smaller in soft (mean +/- standard deviation [SD], 0.29 +/- 0.16 mm) and bone (0.23 +/- 0.05 mm) than in other convolution kernels (p < 0.01). CONCLUSION The accuracy of diameter measurement was affected by the vascular model inner diameter, the density of contrast medium, and the convolution kernel. A higher density of intravascular contrast medium and selection of the proper convolution kernel will improve accuracy.
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Affiliation(s)
- Shigeru Suzuki
- Department of Radiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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Schoellnast H, Tillich M, Deutschmann MJ, Deutschmann HA, Schaffler GJ, Portugaller HR. Aortoiliac enhancement during computed tomography angiography with reduced contrast material dose and saline solution flush: influence on magnitude and uniformity of the contrast column. Invest Radiol 2004; 39:20-6. [PMID: 14701985 DOI: 10.1097/01.rli.0000091841.45342.84] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RATIONALE AND OBJECTIVES To compare the magnitude and uniformity of aortoiliac contrast enhancement obtained from uniphasic contrast material injections versus contrast material injections with reduced iodine dose followed by a saline flush in aortoiliac multislice CT angiography (CTA). METHODS Twenty-nine patients with abdominal aortic aneurysms underwent aortoiliac CTA using protocols A and B. With protocol A, 120 mL contrast material (300 mgI/mL), and with protocol B, 100 mL contrast material followed by a 40-mL saline solution flush were administered at a flow rate of 4 mL/s. Quantitative analysis was performed by calculating mean aortoiliac attenuation, mean plateau deviation, and mean difference between maximum and minimum attenuation value for both groups. Qualitative analysis was performed by visual assessment of vascular enhancement using 2-dimensional and 3-dimensional postprocessing techniques. RESULTS The mean aortoiliac attenuation with protocol A was 291 +/- 62 HU, and with protocol B it was 285 +/- 61 HU. The difference of 6 HU was not statistically significant (P = 0.27). Mean plateau deviation was significantly smaller using protocol A than protocol B (16 +/- 9 HU vs. 20 +/- 10 HU, P = 0.03). In addition, the mean difference between maximum and minimum attenuation value was significantly smaller with protocol A than with protocol B (59 +/- 29 HU vs. 72 +/- 32 HU, P = 0.01). Visual analysis showed no difference in contrast material magnitude and homogeneity between the protocols. CONCLUSIONS In aortoiliac CTA, a saline solution flush after contrast material bolus allows an iodine dose reduction of approximately 20 mL without impairing the magnitude of contrast enhancement but degrades the uniformity of the contrast column. However, the degradation does not affect visual analysis.
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Smith JC, Nelson RC, Gimenez EI, Heneghan JP, Thomas J, Delong DM, Kurylo LM. Multidetector helical computed tomography of the liver: comparison of hepatic enhancement using two different contrast media strategies. Acad Radiol 2004; 11:267-71. [PMID: 15035516 DOI: 10.1016/s1076-6332(03)00675-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
RATIONALE AND OBJECTIVES The purpose of this study was to compare hepatic enhancement characteristics using two different contrast media injection protocols with multidetector helical computed tomography. MATERIALS AND METHODS Twenty-three patients with known or suspected liver lesions scheduled to undergo biphasic hepatic multidetector helical computed tomography were randomized into one of two groups: (1) 150 mL of iopamidol (300 mgI/mL) at 5 mL/second, or (2) 100 mL of iopamidol (370 mgI/mL) at 4 mL/second. Unenhanced images were acquired initially, followed by both hepatic arterial phase (scan delay, 33 seconds) and portal venous phase (PVP; scan delay, 65 seconds) imaging. Three abdominal radiologists independently graded the images on a scale from 1-5 for enhancement and overall scan quality. Time-attenuation curves were generated from operator-defined region-of-interest measurements of liver parenchyma and aorta. RESULTS Qualitatively, the three reviewers found no significant difference between the two study groups in terms of overall scan quality (P = .23) or aortic enhancement (hepatic arterial phase, P = .9; PVP, P = .24). However, liver enhancement during the PVP was considered to be less in the Isovue 370 group (P = .04). Quantitatively, during the hepatic arterial phase, there was no statistically significant difference between the two injection protocols comparing either aortic or hepatic parenchymal enhancement (P = .62 and .80, respectively). During the PVP, these differences were statistically significant, with both aortic and hepatic parenchymal enhancement lower in the Isovue 370 group (P < .01 and P = .04, respectively). CONCLUSION It is important to consider the amount of iodine injected per second and the duration of the injection when setting up protocols to achieve target organ enhancement. 100 mL of iopamidol 370 at 4 mL/second can be used to obtain images of the liver with good diagnostic quality compared to more conventional protocols using 150 mL of iopamidol 300 at 5 mL/second. However, the degree of liver parenchymal enhancement during the PVP using the latter injection scheme is lower, which in turn could potentially reduce hepatic lesion conspicuity.
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Affiliation(s)
- Jason C Smith
- Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710, USA
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Boskamp T, Rinck D, Link F, Kümmerlen B, Stamm G, Mildenberger P. New Vessel Analysis Tool for Morphometric Quantification and Visualization of Vessels in CT and MR Imaging Data Sets. Radiographics 2004; 24:287-97. [PMID: 14730052 DOI: 10.1148/rg.241035073] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Image processing algorithms and a prototypical research software tool have been developed for visualization and quantitative analysis of vessels in data sets from computed tomography and magnetic resonance imaging. The software is based on a sequence of processing steps, which are as follows: (a) vessel segmentation based on a region growing algorithm, (b) interactive "premasking" to optionally exclude interfering structures close to the vessels of interest, (c) distance transform-based skeletonization, (d) multiplanar reformation orthogonal to the vessel path, (e) identification of the lumen boundary on the orthogonal cross-section images, and (f) morphometric measurements. The development of the algorithmic components and the application user interface has been carried out in close cooperation with clinical users to achieve a high degree of usability and flexible support of work flow. The software has been successfully applied to the intracranial arteries, carotid arteries, and abdominal and thoracic aorta, as well as the renal, coronary, and peripheral arteries.
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Affiliation(s)
- Tobias Boskamp
- MeVis Center for Medical Diagnostic Systems and Visualization, Universitätsallee 29, 28359 Bremen, Germany.
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Bae KT, McDermott R, Gierada DS, Heiken JP, Nolte MA, Takahashi N, Hong C. Gadolinium-enhanced computed tomography angiography in multi-detector row computed tomography. Acad Radiol 2004; 11:61-8. [PMID: 14746403 DOI: 10.1016/s1076-6332(03)00536-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
RATIONALE AND OBJECTIVES The feasibility of using gadolinium contrast medium for computed tomography angiography (CTA) in multi-detector row computed tomography and the effect of contrast medium dilution was investigated. MATERIALS AND METHODS Three pigs were each scanned in multiple sessions with injections of non-dilute and dilute contrast medium at a dose of 0.3 mmol/kg body weight. Non-spiral dynamic scanning at a fixed mid-abdominal aortic level and thoracoabdominal CTA were performed. RESULTS The magnitude of peak aortic enhancement was not significantly different between dilute and non-dilute contrast medium injections (P = .88), but the former showed earlier enhancement (mean of 2.3 seconds sooner, P < .01) than the latter. CT angiography with gadolinium contrast medium showed much lower enhancement than iodine contrast medium, but small vessels were readily identifiable. CONCLUSION Gadolinium contrast medium combined with multi-detector row computed tomography may provide clinically useful CTA. Dilution of contrast medium shortens the enhancement time but has little effect on the magnitude.
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Affiliation(s)
- Kyongtae T Bae
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Boulevard, St Louis, MO 63110, USA
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Abstract
The authors developed and evaluated a method to produce curved-slab maximum intensity projections (MIPs) through blood vessels that semiautomatically excludes soft tissue and bone. Results obtained with the algorithm were compared with those obtained with rectangular-slab MIPs by using computed tomographic (CT) data from four patients with abdominal aortic aneurysms. Curved-slab MIPs exhibited increased mean vessel-to-perivascular tissue contrast of 55.1 HU (36%), allowed a 10% increase in contrast-to-noise ratio, and decreased apparent vessel narrowing by 0.12-1.09 mm, without increasing processing time. Curved-slab MIPs may also include multiple vessels in a single image, thereby improving interpretation efficiency by reducing the number of MIPs required in these patients from eight to three.
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Affiliation(s)
- Raghav Raman
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5105, USA
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Morgan-Hughes GJ, Owens PE, Marshall AJ, Roobottom CA. Thoracic aorta at multi-detector row CT: motion artifact with various reconstruction windows. Radiology 2003; 228:583-8. [PMID: 12819333 DOI: 10.1148/radiol.2282020873] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The authors assessed motion artifact of the thoracic aorta in 25 patients who underwent multi-detector row computed tomography (CT) with retrospective electrocardiographic (ECG) gating. CT reconstructions centered at four phases of diastole were compared for five different levels of the thoracic aorta. A significant positive correlation was observed between heart rate and motion artifact (r = 0.72, P <.001). The optimal reconstruction phase varied between patients, and this was directly related to heart rate. For patients with a heart rate of 70 beats per minute, the reconstruction phase centered at 75% of the R-R interval had the significantly least motion artifact (P =.004). Conversely, the optimal reconstruction phase for patients with heart rates above 70 beats per minute was centered at 50% of the R-R interval (P =.09).
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Affiliation(s)
- Gareth J Morgan-Hughes
- Departments of Cardiology and Radiology, South West Cardiothoracic Centre, Plymouth NHS Trust, Derriford Rd, Plymouth PL6 8DH, England.
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