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Hsia CCW, Bates JHT, Driehuys B, Fain SB, Goldin JG, Hoffman EA, Hogg JC, Levin DL, Lynch DA, Ochs M, Parraga G, Prisk GK, Smith BM, Tawhai M, Vidal Melo MF, Woods JC, Hopkins SR. Quantitative Imaging Metrics for the Assessment of Pulmonary Pathophysiology: An Official American Thoracic Society and Fleischner Society Joint Workshop Report. Ann Am Thorac Soc 2023; 20:161-195. [PMID: 36723475 PMCID: PMC9989862 DOI: 10.1513/annalsats.202211-915st] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Multiple thoracic imaging modalities have been developed to link structure to function in the diagnosis and monitoring of lung disease. Volumetric computed tomography (CT) renders three-dimensional maps of lung structures and may be combined with positron emission tomography (PET) to obtain dynamic physiological data. Magnetic resonance imaging (MRI) using ultrashort-echo time (UTE) sequences has improved signal detection from lung parenchyma; contrast agents are used to deduce airway function, ventilation-perfusion-diffusion, and mechanics. Proton MRI can measure regional ventilation-perfusion ratio. Quantitative imaging (QI)-derived endpoints have been developed to identify structure-function phenotypes, including air-blood-tissue volume partition, bronchovascular remodeling, emphysema, fibrosis, and textural patterns indicating architectural alteration. Coregistered landmarks on paired images obtained at different lung volumes are used to infer airway caliber, air trapping, gas and blood transport, compliance, and deformation. This document summarizes fundamental "good practice" stereological principles in QI study design and analysis; evaluates technical capabilities and limitations of common imaging modalities; and assesses major QI endpoints regarding underlying assumptions and limitations, ability to detect and stratify heterogeneous, overlapping pathophysiology, and monitor disease progression and therapeutic response, correlated with and complementary to, functional indices. The goal is to promote unbiased quantification and interpretation of in vivo imaging data, compare metrics obtained using different QI modalities to ensure accurate and reproducible metric derivation, and avoid misrepresentation of inferred physiological processes. The role of imaging-based computational modeling in advancing these goals is emphasized. Fundamental principles outlined herein are critical for all forms of QI irrespective of acquisition modality or disease entity.
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Fujita Y, Kent M, Wisner E, Johnson L, Stern J, Qi L, Boone J, Yamamoto T. Combined Assessment of Pulmonary Ventilation and Perfusion with Single-Energy Computed Tomography and Image Processing. Acad Radiol 2021; 28:636-646. [PMID: 32534966 DOI: 10.1016/j.acra.2020.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 10/24/2022]
Abstract
RATIONALE AND OBJECTIVES To establish a proof-of-principle for combined assessment of pulmonary ventilation and perfusion using single-energy computed tomography (CT) and image processing/analysis (denoted as single-energy CT ventilation/perfusion imaging). MATERIALS AND METHODS Breath-hold CT scans were acquired at end-expiration and end-inspiration before injection of iodinated contrast agents, and repeated at end-inspiration after contrast injection for 17 canines (8 normal and 9 diseased lung subjects). Ventilation images were calculated with deformable image registration to map the end-expiratory and end-inspiratory CT images and quantitative analysis for regional volume changes as surrogates for ventilation. Perfusion images were calculated by subtracting the end-inspiratory precontrast CT from the deformably registered end-inspiratory postcontrast CT, yielding a map of regional Hounsfield unit enhancement as a surrogate for perfusion. Ventilation-perfusion matching, spatial heterogeneity, and gravitationally directed gradients were compared between two groups using a Wilcoxon rank-sum test. RESULTS The normal group had significantly higher Dice similarity coefficients for spatial overlap of segmented functional volumes between ventilation and perfusion (median 0.40 vs. 0.33, p = 0.05), suggesting stronger ventilation-perfusion matching. The normal group also had greater Spearman's correlation coefficients based on 16 regions of interest (median 0.58 vs. 0.40, p = 0.09). The coefficients of variation were comparable (median, ventilation 0.71 vs. 0.91, p = 0.60; perfusion 0.63 vs. 0.75, p = 0.27). The linear regression slopes of gravitationally directed gradient were also comparable for ventilation (median, ventilation -0.26 vs. -0.18, p = 0.19; perfusion -0.17 vs. -0.06, p = 0.11). CONCLUSION These findings provide proof-of-principle for single-energy CT ventilation/perfusion imaging.
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Jimenez-Juan L, Mehrez H, Dey C, Homampour S, Salazar-Ferrer P, Granton JT, Lee TY, Paul N. Quantitative assessment of pulmonary artery occlusion using lung dynamic perfusion CT. Sci Rep 2021; 11:483. [PMID: 33436837 PMCID: PMC7804280 DOI: 10.1038/s41598-020-80177-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/14/2020] [Indexed: 11/09/2022] Open
Abstract
Quantitative measurement of lung perfusion is a promising tool to evaluate lung pathophysiology as well as to assess disease severity and monitor treatment. However, this novel technique has not been adopted clinically due to various technical and physiological challenges; and it is still in the early developmental phase where the correlation between lung pathophysiology and perfusion maps is being explored. The purpose of this research work is to quantify the impact of pulmonary artery occlusion on lung perfusion indices using lung dynamic perfusion CT (DPCT). We performed Lung DPCT in ten anesthetized, mechanically ventilated juvenile pigs (18.6–20.2 kg) with a range of reversible pulmonary artery occlusions (0%, 40–59%, 60–79%, 80–99%, and 100%) created with a balloon catheter. For each arterial occlusion, DPCT data was analyzed using first-pass kinetics to derive blood flow (BF), blood volume (BV) and mean transit time (MTT) perfusion maps. Two radiologists qualitatively assessed perfusion maps for the presence or absence of perfusion defects. Perfusion maps were also analyzed quantitatively using a linear segmented mixed model to determine the thresholds of arterial occlusion associated with perfusion derangement. Inter-observer agreement was assessed using Kappa statistics. Correlation between arterial occlusion and perfusion indices was evaluated using the Spearman-rank correlation coefficient. Our results determined that perfusion defects were detected qualitatively in BF, BV and MTT perfusion maps for occlusions larger than 55%, 80% and 55% respectively. Inter-observer agreement was very good with Kappa scores > 0.92. Quantitative analysis of the perfusion maps determined the arterial occlusion threshold for perfusion defects was 50%, 76% and 44% for BF, BV and MTT respectively. Spearman-rank correlation coefficients between arterial occlusion and normalized perfusion values were strong (− 0.92, − 0.72, and 0.78 for BF, BV and MTT, respectively) and were statically significant (p < 0.01). These findings demonstrate that lung DPCT enables quantification and stratification of pulmonary artery occlusion into three categories: mild, moderate and severe. Severe (occlusion ≥ 80%) alters all perfusion indices; mild (occlusion < 55%) has no detectable effect. Moderate (occlusion 55–80%) impacts BF and MTT but BV is preserved.
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Affiliation(s)
- Laura Jimenez-Juan
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.,Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, ON, Canada
| | - Hatem Mehrez
- Canon Medical Systems Canada, Markham, ON, Canada
| | - Chris Dey
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.,Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, ON, Canada
| | - Shabnam Homampour
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.,Joint Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada
| | | | - John T Granton
- Division of Respirology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Ting-Yim Lee
- Imaging Division, Lawson Health Research Institute, Imaging Research Laboratories, Research Institute, London, ON, Canada
| | - Narinder Paul
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada. .,Joint Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada. .,Department of Medical Imaging, London Health Sciences Centre, St Joseph's Hospital, Western University, London, ON, Canada.
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Nestler K, Becker BV, Majewski M, Veit DA, Krull BF, Waldeck S. Additional CTA-Subtraction Technique in Detection of Pulmonary Embolism-a Benefit for Patients or Only an Increase in Dose? HEALTH PHYSICS 2020; 119:148-152. [PMID: 32371851 DOI: 10.1097/hp.0000000000001274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Latest advantages in computed tomography (CT) come with enhanced diagnostic imaging and also sophisticated dose reduction techniques. However, overall exposure to ionizing radiation of patients in Germany rises slightly, which is mainly based on the growing number of performed CT scans. Furthermore, new possibilities in modern imaging, including 4D scans or perfusion protocols, offer new medical insights but require additional scans.In this study, we reevaluated data sets from patients undergoing CT examinations because of suspected pulmonary embolism and compared doses and diagnostic results of the standard protocol to the additional modern CT subtraction technique. Two groups of single-blinded radiologists were provided with CT data sets from 50 patients. One group (G1) had access to full datasets including CT subtraction with perfusion map. The other group (G2) only evaluated conventional CT angiography. Results were compared to final clinical diagnosis. Dose length product (DLP) of CT angiography was compared to CT subtraction technique, which consists of an additional non-contrast-enhanced scan and perfusion map. Effective dose was calculated using a Monte Carlo simulation-based software tool (ImpactDose). Inter-rater agreement of both groups was strong in G1 with κ = .896 and minimal in G2 (κ = .307). Agreement to final diagnosis was strong in both groups (G1, κ = .848; G2, κ = .767). Doses applied using the CT subtraction technique were 34.8% higher than for CT angiography alone (G1 DLP 337.6 ± 171.3 mGy x cm; G2 DLP 220.2 ± 192.8 mGy x cm; p < .001). Calculated effective dose was therefore significantly higher for G1 (G1 4.82 ± 2.20 mSv; G2 3.04 ± 1.33 mSv; p < .001). Our results indicate a benefit of the CT subtraction technique for the detection of pulmonary embolisms in clinical routine, accompanied by an increase in the dose administered. Although CT protocols should always be applied carefully to specific clinical indications in order to maximize the potential for dose reduction and keep the administered dose as low as reasonably achievable, one should never lose sight of the diagnostic benefit, especially in vital clinical indications.
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Affiliation(s)
| | - Benjamin Valentin Becker
- German Federal Armed Forces Central Hospital Koblenz, Department for Radiology and Neuroradiology, Koblenz, Germany
| | - Matthäus Majewski
- Bundeswehr Institute for Radiobiology affiliated to Ulm University, Munich, Germany
| | - Daniel Anton Veit
- German Federal Armed Forces Central Hospital Koblenz, Department for Radiology and Neuroradiology, Koblenz, Germany
| | - Bastian Felix Krull
- German Federal Armed Forces Central Hospital Koblenz, Department for Radiology and Neuroradiology, Koblenz, Germany
| | - Stephan Waldeck
- German Federal Armed Forces Central Hospital Koblenz, Department for Radiology and Neuroradiology, Koblenz, Germany
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Grob D, Smit E, Prince J, Kist J, Stöger L, Geurts B, Snoeren MM, van Dijk R, Oostveen LJ, Prokop M, Schaefer-Prokop CM, Sechopoulos I, Brink M. Iodine Maps from Subtraction CT or Dual-Energy CT to Detect Pulmonary Emboli with CT Angiography: A Multiple-Observer Study. Radiology 2019; 292:197-205. [DOI: 10.1148/radiol.2019182666] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Dagmar Grob
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Ewoud Smit
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Jip Prince
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Jakob Kist
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Lauran Stöger
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Bram Geurts
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Miranda M. Snoeren
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Rogier van Dijk
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Luuk J. Oostveen
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Mathias Prokop
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Cornelia M. Schaefer-Prokop
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Ioannis Sechopoulos
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
| | - Monique Brink
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (D.G., E.S., B.G., M.M.S., L.L.O., M.P., I.S., M.B.); and Department of Radiology and Nuclear Medicine, Meander Medical Centre, Amersfoort, the Netherlands (J.P., J.K., L.S., R.v.D., C.M.S.P.)
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Grob D, Oostveen L, Rühaak J, Heldmann S, Mohr B, Michielsen K, Dorn S, Prokop M, Kachelrieβ M, Brink M, Sechopoulos I. Accuracy of registration algorithms in subtraction CT of the lungs: A digital phantom study. Med Phys 2019; 46:2264-2274. [PMID: 30888690 PMCID: PMC6849605 DOI: 10.1002/mp.13496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 02/15/2019] [Accepted: 03/07/2019] [Indexed: 12/20/2022] Open
Abstract
Purpose The purpose of this study was to assess, using an anthropomorphic digital phantom, the accuracy of algorithms in registering precontrast and contrast‐enhanced computed tomography (CT) chest images for generation of iodine maps of the pulmonary parenchyma via temporal subtraction. Materials and methods The XCAT phantom, with enhanced airway and pulmonary vessel structures, was used to simulate precontrast and contrast‐enhanced chest images at various inspiration levels and added CT simulation for realistic system noise. Differences in diaphragm position were varied between 0 and 20 mm, with the maximum chosen to exceed the 95th percentile found in a dataset of 100 clinical subtraction CTs. In addition, the influence of whole body movement, degree of iodine enhancement, beam hardening artifacts, presence of nodules and perfusion defects in the pulmonary parenchyma, and variation in noise on the registration were also investigated. Registration was performed using three lung registration algorithms — a commercial (algorithm A) and a prototype (algorithm B) version from Canon Medical Systems and an algorithm from the MEVIS Fraunhofer institute (algorithm C). For each algorithm, we calculated the voxel‐by‐voxel difference between the true deformation and the algorithm‐estimated deformation in the lungs. Results The median absolute residual error for all three algorithms was smaller than the voxel size (1.0 × 1.0 × 1.0 mm3) for up to an 8 mm diaphragm difference, which is the average difference in diaphragm levels found clinically, and increased with increasing difference in diaphragm position. At 20 mm diaphragm displacement, the median absolute residual error after registration was 0.85 mm (interquartile range, 0.51–1.47 mm) for algorithm A, 0.82 mm (0.50–1.40 mm) for algorithm B, and 0.91 mm (0.54–1.52 mm) for algorithm C. The largest errors were seen in the paracardiac regions and close to the diaphragm. The impact of all other evaluated conditions on the residual error varied, resulting in an increase in the median residual error lower than 0.1 mm for all algorithms, except in the case of whole body displacements for algorithm B, and with increased noise for algorithm C. Conclusion Motion correction software can compensate for respiratory and cardiac motion with a median residual error below 1 mm, which was smaller than the voxel size, with small differences among the tested registration algorithms for different conditions. Perfusion defects above 50 mm will be visible with the commercially available subtraction CT software, even in poorly registered areas, where the median residual error in that area was 7.7 mm.
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Affiliation(s)
- Dagmar Grob
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Luuk Oostveen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Jan Rühaak
- Fraunhofer Institute for Medical Image Computing MEVIS, Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Maria-Goeppert-Str. 3, 23562, Lübeck, Germany
| | - Stefan Heldmann
- Fraunhofer Institute for Medical Image Computing MEVIS, Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Maria-Goeppert-Str. 3, 23562, Lübeck, Germany
| | - Brian Mohr
- Canon Medical Research Europe, Anderson Place 2, E6 5NP, Edinburgh, Scotland
| | - Koen Michielsen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Sabrina Dorn
- German Cancer Research Center, Heidelberg (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Mathias Prokop
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Marc Kachelrieβ
- German Cancer Research Center, Heidelberg (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Monique Brink
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Ioannis Sechopoulos
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands.,Dutch Expert Center for Screening (LRCB), Wijchenseweg 101, 6538 SW, Nijmegen, The Netherlands
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Maschke SK, Winther HMB, Meine T, Werncke T, Olsson KM, Hoeper MM, Baumgart J, Wacker FK, Meyer BC, Renne J, Hinrichs JB. Evaluation of a newly developed 2D parametric parenchymal blood flow technique with an automated vessel suppression algorithm in patients with chronic thromboembolic pulmonary hypertension undergoing balloon pulmonary angioplasty. Clin Radiol 2019; 74:437-444. [PMID: 30890260 DOI: 10.1016/j.crad.2018.12.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 12/03/2018] [Indexed: 12/21/2022]
Abstract
AIM To evaluate the feasibility of two-dimensional parametric parenchymal blood flow (2D-PPBF) to quantify perfusion changes in the lung parenchyma following balloon pulmonary angioplasty (BPA) for treatment of chronic thromboembolic pulmonary hypertension. MATERIALS AND METHODS Overall, 35 consecutive interventions in 18 patients with 98 treated pulmonary arteries were included. To quantify changes in pulmonary blood flow using 2D-PPBF, the acquired digital subtraction angiography (DSA) series were post-processed using dedicated software. A reference region of interest (ROI; arterial inflow) in the treated pulmonary artery and a distal target ROI, including the whole lung parenchyma distal to the targeted stenosis, were placed in corresponding areas on DSA pre- and post-BPA. Half-peak density (HPD), wash-in rate (WIR), arrival to peak (AP), area under the curve (AUC), and mean transit time (MTT) were assessed. The ratios of the reference ROI to the target ROI (HPDparenchyma/HPDinflow, WIRparenchyma/WIRinflow; APparenchyma/APinflow, AUCparenchyma/AUCinflow, MTTparenchyma/MTTinflow) were calculated. The relative differences of the 2D-PPBF parameters were correlated to changes in the pulmonary flow grade score. RESULTS The pulmonary flow grade score improved significantly after BPA (1 versus 3; p<0.0001). Likewise, the mean HPDparenchyma/HPDinflow (-10.2%; p<0.0001), APparenchyma/APinflow (-24.4%; p=0.0007), and MTTparenchyma/MTTinflow (-3.5%; p=0.0449) decreased significantly, whereas WIRparenchyma/WIRinflow (+82.4%) and AUCparenchyma/AUCinflow (+58.6%) showed a significant increase (p<0.0001). Furthermore, a significant correlation between changes of the pulmonary flow grade score and changes of HPDparenchyma/HPDinflow (ρ=-0.21, p=0.04), WIRparenchyma/WIRinflow (ρ=0.43, p<0.0001), APparenchyma/APinflow (ρ=-0.22, p=0.03), AUCparenchyma/AUCinflow (ρ=0.48, p<0.0001), and MTTparenchyma/MTTinflow (ρ=-0.39, p<0.0001) could be observed. CONCLUSION The 2D-PPBF technique is feasible for the quantification of perfusion changes following BPA and has the potential to improve monitoring of BPA.
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Affiliation(s)
- S K Maschke
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - H M B Winther
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - T Meine
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - T Werncke
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - K M Olsson
- Clinic for Pneumology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - M M Hoeper
- Clinic for Pneumology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - J Baumgart
- Siemens Medical Solutions USA, Inc., Angiography, Fluoroscopic and Radiographic Systems, Hoffman Estates, IL, USA
| | - F K Wacker
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - B C Meyer
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - J Renne
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany
| | - J B Hinrichs
- Department of Diagnostic and Interventional Radiology, Member of the German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany.
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Imaging of pulmonary perfusion using subtraction CT angiography is feasible in clinical practice. Eur Radiol 2018; 29:1408-1414. [PMID: 30255247 PMCID: PMC6510874 DOI: 10.1007/s00330-018-5740-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/24/2018] [Accepted: 08/28/2018] [Indexed: 01/06/2023]
Abstract
Abstract Subtraction computed tomography (SCT) is a technique that uses software-based motion correction between an unenhanced and an enhanced CT scan for obtaining the iodine distribution in the pulmonary parenchyma. This technique has been implemented in clinical practice for the evaluation of lung perfusion in CT pulmonary angiography (CTPA) in patients with suspicion of acute and chronic pulmonary embolism, with acceptable radiation dose. This paper discusses the technical principles, clinical interpretation, benefits and limitations of arterial subtraction CTPA. Key Points • SCT uses motion correction and image subtraction between an unenhanced and an enhanced CT scan to obtain iodine distribution in the pulmonary parenchyma. • SCT could have an added value in detection of pulmonary embolism. • SCT requires only software implementation, making it potentially more widely available for patient care than dual-energy CT.
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Lapointe A, Bahig H, Blais D, Bouchard H, Filion É, Carrier JF, Bedwani S. Assessing lung function using contrast-enhanced dual-energy computed tomography for potential applications in radiation therapy. Med Phys 2017; 44:5260-5269. [PMID: 28718888 DOI: 10.1002/mp.12475] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/15/2017] [Accepted: 07/11/2017] [Indexed: 11/08/2022] Open
Abstract
PURPOSE There is an increasing interest in the evaluation of lung function from physiological images in radiation therapy treatment planning to reduce the extent of postradiation toxicities. The purpose of this work was to retrieve reliable functional information from contrast-enhanced dual-energy computed tomography (DECT) for new applications in radiation therapy. The functional information obtained by DECT is also compared with other methods using single-energy CT (SECT) and single-photon emission computed tomography (SPECT) with CT. The differential function between left and right lung, as well as between lobes is computed for all methods. METHODS Five lung cancer patients were retrospectively selected for this study; each underwent a SPECT/CT scan and a contrast-injected DECT scan, using 100 and 140 Sn kVp. The DECT images are postprocessed into iodine concentration maps, which are further used to determine the perfused blood volume. These maps are calculated in two steps: (a) a DECT stoichiometric calibration adapted to the presence of iodine and followed by (b) a two-material decomposition technique. The functional information from SECT is assumed proportional to the HU numbers from a mixed CT image. The functional data from SPECT/CT are considered proportional to the number of counts. A radiation oncologist segmented the entire lung volume into five lobes on both mixed CT images and low-dose CT images from SPECT/CT to allow a regional comparison. The differential function for each subvolume is computed relative to the entire lung volume. RESULTS The differential function per lobe derived from SPECT/CT correlates strongly with DECT (Pearson's coefficient r = 0.91) and moderately with SECT (r = 0.46). The differential function for the left lung shows a mean difference of 7% between SPECT/CT and DECT; and 17% between SPECT/CT and SECT. The presence of nonfunctional areas, such as localized emphysema or a lung tumor, is reflected by an intensity drop in the iodine concentration maps. Functional dose volume histograms (fDVH) are also generated for two patients as a proof of concept. CONCLUSION The extraction of iodine concentration maps from a contrast-enhanced DECT scan is achieved to compute the differential function for each lung subvolume and good agreement is found in respect to SPECT/CT. One promising avenue in radiation therapy is to include such functional information during treatment planning dose optimization to spare functional lung tissues.
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Affiliation(s)
- Andréanne Lapointe
- Département de physique, Université de Montréal, Pavillon Roger-Gaudry (D-428), 2900 boulevard Édouard-Montpetit, Montréal, Québec, H3T 1J4, Canada
| | - Houda Bahig
- Département de radio-oncologie, Centre hospitalier de l'Université de Montréal (CHUM), 1560 rue Sherbrooke est, Montréal, Québec, H2L 4M1, Canada
| | - Danis Blais
- Département de radio-oncologie, Centre hospitalier de l'Université de Montréal (CHUM), 1560 rue Sherbrooke est, Montréal, Québec, H2L 4M1, Canada
| | - Hugo Bouchard
- Département de physique, Université de Montréal, Pavillon Roger-Gaudry (D-428), 2900 boulevard Édouard-Montpetit, Montréal, Québec, H3T 1J4, Canada.,Département de radio-oncologie, Centre hospitalier de l'Université de Montréal (CHUM), 1560 rue Sherbrooke est, Montréal, Québec, H2L 4M1, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal, 900 rue Saint-Denis, Montréal, Québec, H2X 0A9, Canada
| | - Édith Filion
- Département de radio-oncologie, Centre hospitalier de l'Université de Montréal (CHUM), 1560 rue Sherbrooke est, Montréal, Québec, H2L 4M1, Canada
| | - Jean-François Carrier
- Département de physique, Université de Montréal, Pavillon Roger-Gaudry (D-428), 2900 boulevard Édouard-Montpetit, Montréal, Québec, H3T 1J4, Canada.,Département de radio-oncologie, Centre hospitalier de l'Université de Montréal (CHUM), 1560 rue Sherbrooke est, Montréal, Québec, H2L 4M1, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal, 900 rue Saint-Denis, Montréal, Québec, H2X 0A9, Canada
| | - Stéphane Bedwani
- Département de physique, Université de Montréal, Pavillon Roger-Gaudry (D-428), 2900 boulevard Édouard-Montpetit, Montréal, Québec, H3T 1J4, Canada.,Département de radio-oncologie, Centre hospitalier de l'Université de Montréal (CHUM), 1560 rue Sherbrooke est, Montréal, Québec, H2L 4M1, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal, 900 rue Saint-Denis, Montréal, Québec, H2X 0A9, Canada
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Yamamoto T, Kent MS, Wisner ER, Johnson LR, Stern JA, Qi L, Fujita Y, Boone JM. Single-energy computed tomography-based pulmonary perfusion imaging: Proof-of-principle in a canine model. Med Phys 2017; 43:3998. [PMID: 27370118 PMCID: PMC5438244 DOI: 10.1118/1.4953188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose: Radiotherapy (RT) that selectively avoids irradiating highly functional
lung
regions may reduce pulmonary toxicity, which is substantial in lung
cancer RT.
Single-energy computed
tomography
(CT)
pulmonary perfusion imaging has several advantages
(e.g., higher resolution) over other modalities and has great potential for
widespread clinical implementation, particularly in RT. The purpose of this study
was to establish proof-of-principle for single-energy CT perfusion
imaging. Methods: Single-energy CT perfusion imaging is based on the following:
(1) acquisition of end-inspiratory breath-hold CT scans before and
after intravenous injection of iodinated contrast agents, (2)
deformable image
registration (DIR) for spatial mapping of
those two CT
image
data sets,
and (3) subtraction of the precontrast image
data set
from the postcontrast image
data set,
yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for
regional perfusion. In a protocol approved by the institutional animal care and
use committee, the authors acquired CT scans in the prone position for a total of 14
anesthetized canines (seven canines with normal lungs and seven
canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy
of DIR was evaluated based on the target registration error (TRE) of 50 anatomic
pulmonary landmarks per subject for 10 randomly selected subjects as well as on
singularities (i.e., regions where the displacement vector field is not
bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory
image were corrected for variation in the lung inflation level
between the precontrast and postcontrast end-inspiratory CT scans, using a
model built from two additional precontrast CT scans at
end-expiration and midinspiration. The authors also assessed spatial heterogeneity
and gravitationally directed gradients of regional perfusion for normal
lung
subjects and diseased lung subjects using a two-sample two-tailed
t-test. Results: The mean TRE (and standard deviation) was 0.6 ± 0.7 mm (smaller than the voxel
dimension) for DIR between pre contrast and postcontrast end-inspiratory
CT
image
data sets.
No singularities were observed in the displacement vector fields. The mean HU
enhancement (and standard deviation) was 37.3 ± 10.5 HU for normal lung subjects and 30.7
± 13.5 HU for diseased lung subjects. Spatial heterogeneity of regional perfusion was
found to be higher for diseased lung subjects than for normal lung subjects, i.e., a
mean coefficient of variation of 2.06 vs 1.59 (p = 0.07). The
average gravitationally directed gradient was strong and significant
(R2 = 0.99, p < 0.01) for
normal lung dogs, whereas it was moderate and nonsignificant
(R2 = 0.61, p = 0.12) for diseased
lung
dogs. Conclusions: This canine study demonstrated the accuracy of DIR with subvoxel TREs on average,
higher spatial heterogeneity of regional perfusion for diseased
lung
subjects than for normal lung subjects, and a strong gravitationally directed gradient
for normal lung subjects, providing proof-of-principle for single-energy
CT
pulmonary perfusion imaging. Further studies such as
comparison with other perfusion imaging modalities will be necessary
to validate the physiological significance.
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Affiliation(s)
- Tokihiro Yamamoto
- Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, California 95817
| | - Michael S Kent
- Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, California 95616
| | - Erik R Wisner
- Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, California 95616
| | - Lynelle R Johnson
- Department of Medicine and Epidemiology, University of California Davis School of Veterinary Medicine, Davis, California 95616
| | - Joshua A Stern
- Department of Medicine and Epidemiology, University of California Davis School of Veterinary Medicine, Davis, California 95616
| | - Lihong Qi
- Department of Public Health Sciences, University of California Davis, Davis, California 95616
| | - Yukio Fujita
- Department of Radiation Oncology, Tokai University, Isehara, Kanagawa 259-1193, Japan
| | - John M Boone
- Department of Radiology, University of California Davis School of Medicine, Sacramento, California 95817
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Doğan H, de Roos A, Geleijins J, Huisman MV, Kroft LJM. The role of computed tomography in the diagnosis of acute and chronic pulmonary embolism. Diagn Interv Radiol 2016; 21:307-16. [PMID: 26133321 DOI: 10.5152/dir.2015.14403] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pulmonary embolism (PE) is a potentially life threatening condition requiring adequate diagnosis and treatment. Computed tomography pulmonary angiography (CTPA) is excellent for including and excluding PE, therefore CT is the first-choice diagnostic imaging technique in patients suspected of having acute PE. Due to its wide availability and low invasiveness, CTPA tends to be overused. Correct implementation of clinical decision rules in diagnostic workup for PE improves adequate use of CT. Also, CT adds prognostic value by evaluating right ventricular (RV) function. CT-assessed RV dysfunction and to lesser extent central emboli location predicts PE-related mortality in normotensive and hypotensive patients, while PE embolic obstruction index has limited prognostic value. Simple RV/left ventricular (LV) diameter ratio measures >1.0 already predict risk for adverse outcome, whereas ratios <1.0 can safely exclude adverse outcome. Consequently, assessing the RV/LV diameter ratio may help identify patients who are potential candidates for treatment at home instead of treatment in the hospital. A minority of patients develop chronic thromboembolic pulmonary hypertension (CTEPH) following acute PE, which is a life-threatening condition that can be diagnosed by CT. In proximal CTEPH, involving the more central pulmonary arteries, thrombectomy usually results in good outcome in terms of both functional status and long-term survival rate. CT is becoming the imaging method of choice for diagnosing CTEPH as it can identify patients who may benefit from thrombectomy. New CT developments such as distensibility measurements and dual-energy or subtraction techniques may further refine diagnosis and prognosis for improved patient care.
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Affiliation(s)
- Halil Doğan
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
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12
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Jimenez-Juan L, Mehrez H, Dey C, Homampour S, Oikonomou A, Ursani F, Paul N. Arterial input function placement effect on computed tomography lung perfusion maps. Quant Imaging Med Surg 2016; 6:25-34. [PMID: 26981452 DOI: 10.3978/j.issn.2223-4292.2016.01.05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND A critical source of variability in dynamic perfusion computed tomography (DPCT) is the arterial input function (AIF). However, the impact of the AIF location in lung DPCT has not been investigated yet. The purpose of this study is to determine whether the location of the AIF within the central pulmonary arteries influences the accuracy of lung DPCT maps. METHODS A total of 54 lung DPCT scans were performed in three pigs using different rates and volumes of iodinated contrast media. Pulmonary blood flow (PBF) perfusion maps were generated using first-pass kinetics in three different AIF locations: the main pulmonary trunk (PT), the right main (RM) and the left main (LM) pulmonary arteries. A total of 162 time density curves (TDCs) and corresponding PBF perfusion maps were generated. Linear regression and Spearman's rank correlation coefficient were used to compare the TDCs. PBF perfusion maps were compared quantitatively by taking twenty six regions of interest throughout the lung parenchyma. Analysis of variance (ANOVA) was used to compare the mean PBF values among the three AIF locations. Two chest radiologists performed qualitative assessment of the perfusion maps using a 3-point scale to determine regions of perfusion mismatch. RESULTS The linear regression of the TDCs from the RM and LM compared to the PT had a median (range) of 1.01 (0.98-1.03). The Spearman rank correlation between the TDCs was 0.88 (P<0.05). ANOVA analysis of the perfusion maps demonstrated no statistical difference (P>0.05). Qualitative comparison of the perfusion maps resulted in scores of 1 and 2, demonstrating either identical or comparable maps with no significant difference in perfusion defects between the different AIF locations. CONCLUSIONS Accurate PBF perfusion maps can be generated with the AIF located either at the PT, RM or LM pulmonary arteries.
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Affiliation(s)
- Laura Jimenez-Juan
- 1 Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada ; 2 Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, Ontario, Canada ; 3 Toshiba Medical Systems, Markham, Ontario, Canada ; 4 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada ; 5 Department of Biology, University of Toronto, Toronto, Ontario, Canada
| | - Hatem Mehrez
- 1 Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada ; 2 Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, Ontario, Canada ; 3 Toshiba Medical Systems, Markham, Ontario, Canada ; 4 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada ; 5 Department of Biology, University of Toronto, Toronto, Ontario, Canada
| | - Chris Dey
- 1 Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada ; 2 Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, Ontario, Canada ; 3 Toshiba Medical Systems, Markham, Ontario, Canada ; 4 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada ; 5 Department of Biology, University of Toronto, Toronto, Ontario, Canada
| | - Shabnam Homampour
- 1 Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada ; 2 Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, Ontario, Canada ; 3 Toshiba Medical Systems, Markham, Ontario, Canada ; 4 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada ; 5 Department of Biology, University of Toronto, Toronto, Ontario, Canada
| | - Anastasia Oikonomou
- 1 Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada ; 2 Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, Ontario, Canada ; 3 Toshiba Medical Systems, Markham, Ontario, Canada ; 4 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada ; 5 Department of Biology, University of Toronto, Toronto, Ontario, Canada
| | - Fatima Ursani
- 1 Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada ; 2 Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, Ontario, Canada ; 3 Toshiba Medical Systems, Markham, Ontario, Canada ; 4 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada ; 5 Department of Biology, University of Toronto, Toronto, Ontario, Canada
| | - Narinder Paul
- 1 Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada ; 2 Department of Medical Imaging, Sunnybrook Health Science Centre, Toronto, Ontario, Canada ; 3 Toshiba Medical Systems, Markham, Ontario, Canada ; 4 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada ; 5 Department of Biology, University of Toronto, Toronto, Ontario, Canada
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Where do we stand? Functional imaging in acute and chronic pulmonary embolism with state-of-the-art CT. Eur J Radiol 2015; 84:2432-7. [DOI: 10.1016/j.ejrad.2015.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 09/17/2015] [Indexed: 01/26/2023]
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Coupal TM, Mallinson PI, McLaughlin P, Nicolaou S, Munk PL, Ouellette H. Peering through the glare: using dual-energy CT to overcome the problem of metal artefacts in bone radiology. Skeletal Radiol 2014; 43:567-75. [PMID: 24435711 DOI: 10.1007/s00256-013-1802-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 12/06/2013] [Accepted: 12/11/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Imaging of patients with large metal implants remains one of the most difficult endeavours for radiologists. This article reviews the theory of dual-energy CT (DECT) and its ability to reduce metal artefact, thus enhancing the diagnostic value of musculoskeletal imaging. The strengths, weaknesses, and alternative applications of DECT, as well as areas requiring further research, will also be reviewed. CONCLUSION Currently, DECT stands as the frontier for metal artefact reduction in musculoskeletal imaging. DECT requires no additional radiation and provides significantly enhanced image acquisition. When considered along with its other capabilities, DECT is a promising new tool for musculoskeletal and trauma radiologists.
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Affiliation(s)
- Tyler M Coupal
- Michael G. DeGroote School of Medicine, McMaster University, 1280 Main St W, Hamilton, ON, Canada, L8S 4 K1
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15
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Sun H, Gao F, Li N, Liu C. An evaluation of the feasibility of assessment of volume perfusion for the whole lung by 128-slice spiral CT. Acta Radiol 2013; 54:921-7. [PMID: 23761560 DOI: 10.1177/0284185113490151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Lung perfusion based on dynamic scanning cannot provide a quantitative assessment of the whole lung because of the limited coverage of the current computed tomography (CT) detector designs. PURPOSE To evaluate the feasibility of dynamic volume perfusion CT (VPCT) of the whole lung using a 128-slice CT for the quantitative assessment and visualization of pulmonary perfusion. MATERIAL AND METHODS Imaging was performed in a control group of 17 subjects who had no signs of disturbance of pulmonary function or diffuse lung disease, and 15 patients (five patients with acute pulmonary embolism and 10 with emphysema) who constituted the abnormal lung group. Dynamic VPCT was performed in all subjects, and pulmonary blood flow (PBF), pulmonary blood volume (PBV), and mean transit time (MTT) were calculated from dynamic contrast images with a coverage of 20.7 cm. Regional and volumetric PBF, PBV, and MTT were statistically evaluated and comparisons were made between the normal and abnormal lung groups. RESULTS Regional PBF (94.2 ± 36.5, 161.8 ± 29.6, 185.7 ± 38.1 and 125.5 ± 46.1, 161.9 ± 31.4, 169.3 ± 51.7), PBV (6.7 ± 2.8, 10.9 ± 3.0, 12.9 ± 4.5 and 9.9 ± 4.6, 10.3 ± 2.9, 11.9 ± 4.5), and MTT (5.8 ± 2.4, 4.5 ± 1.3, 4.7 ± 2.1 and 5.6 ± 2.3, 4.3 ± 1.5, 4.9 ± 1.5) demonstrated significant differences in the gravitational and isogravitational directions in the normal lung group (P < 0.05). The PBF (154.2 ± 30.6 vs. 94.9 ± 15.9) and PBV (11.1 ± 4.0 vs. 6.6 ± 1.7) by dynamic VPCT showed significant differences between normal and abnormal lungs (P < 0.05), notwithstanding the four large lungs that had coverage > 20.7 cm. CONCLUSION Dynamic VPCT of the whole lung is feasible for the quantitative assessment of pulmonary perfusion by 128-slice CT, and may in future permit the evaluation of both morphological and functional features of the whole lung in a single examination.
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Affiliation(s)
- Haitao Sun
- Imaging Center of Taian Central Hospital, Taian, Shandong
| | - Fei Gao
- Shandong University, Shandong Medical Imaging Research Institute, CT Room, Shandong, China
| | - Ning Li
- Shandong University, Shandong Medical Imaging Research Institute, CT Room, Shandong, China
| | - Cheng Liu
- Shandong University, Shandong Medical Imaging Research Institute, CT Room, Shandong, China
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Geyer LL, Scherr M, Körner M, Wirth S, Deak P, Reiser MF, Linsenmaier U. Imaging of acute pulmonary embolism using a dual energy CT system with rapid kVp switching: Initial results. Eur J Radiol 2012; 81:3711-8. [DOI: 10.1016/j.ejrad.2011.02.043] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 02/22/2011] [Indexed: 11/15/2022]
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Abstract
Computed tomography (CT) is the modality of choice for imaging the airways. Volumetric data sets with isotropic spatial resolution based on multidetector thin-section CT with overlapping reconstruction should be used. Chronic obstructive pulmonary disease and asthma are the 2 most common disease entities that are defined by airflow obstruction. The morphologic correlates of airway changes are dilation of the lumen, thickening of the wall, visibility of small airways due to mucus or edema, air trapping, hypoxic vasoconstriction, and collapsibility. To assess air trapping, additional expiratory low-dose scans are recommended. In clinical routine, these findings are visually assessed and should be routinely reported. However, the interobserver variability is high, and there is a clear need for objective software-based measurements. The development of such tools is challenging, and they are just becoming available on a broader scale. Novel techniques based on dual-energy CT aim to measure iodine distribution maps to assess pulmonary perfusion as well as the distribution of inhaled xenon gas to assess the distribution and time course of pulmonary ventilation. However, these techniques are still being investigated in clinical studies. This review will provide an overview of CT for the diagnosis of chronic obstructive pulmonary disease and asthma, its role in phenotyping these diseases, and the measurement of disease severity and functional compromise.
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Lung Perfused Blood Volume Images With Dual-Energy Computed Tomography for Chronic Thromboembolic Pulmonary Hypertension. J Comput Assist Tomogr 2011; 35:590-5. [DOI: 10.1097/rct.0b013e318224e227] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Barbash IM, Schenke WH, Halabi M, Ratnayaka K, Faranesh AZ, Kocaturk O, Lederman RJ. Experimental model of large pulmonary embolism employing controlled release of subacute caval thrombus in swine. J Vasc Interv Radiol 2011; 22:1471-7. [PMID: 21802315 DOI: 10.1016/j.jvir.2011.06.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/09/2011] [Accepted: 06/20/2011] [Indexed: 10/17/2022] Open
Abstract
PURPOSE To develop a catheter-based model of large pulmonary embolism (PE) in swine based on in situ venous thrombus formation. MATERIALS AND METHODS Ten Yorkshire swine underwent transjugular implantation of a retrievable inferior vena cava (IVC) filter. A thrombin and collagen mixture was injected into a confined space created by two balloons inflated proximal and distal to the IVC filter. Animals were left to survive for 7 days ± 3 to allow thrombus to organize in situ. The caval thrombus was released on transcatheter retrieval of the IVC filter and embolized into the main and branch pulmonary arteries. The severity of PE was scored based on digital subtraction angiography with the Miller index. At necropsy, thrombi were recovered and analyzed histopathologically. RESULTS Large PE was induced in all animals (Miller index score of 15 ± 5). Two animals developed saddle embolus with bilateral pulmonary artery occlusion, and five developed proximal occlusion of the left or right pulmonary artery. Nevertheless, no animal exhibited significant hemodynamic compromise. Large tubular thrombi were explanted in the size range of 5-10 cm long and 0.5-1 cm wide. Histologic analysis indicated an organized thrombus with infiltration of white blood cells and fibrin deposition. CONCLUSIONS Large caval thrombi can be formed in vivo and released at a predetermined time to induce large PE in a large animal model. This may help in the development and testing of new therapeutic approaches for PE.
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Affiliation(s)
- Israel M Barbash
- Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1538, USA
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Clinical application of dual-source CT in the evaluation of patients with lung cancer: correlation with perfusion scintigraphy and pulmonary function tests. Radiol Med 2011; 116:842-57. [PMID: 21509557 DOI: 10.1007/s11547-011-0674-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Accepted: 10/15/2010] [Indexed: 10/18/2022]
Abstract
PURPOSE This study was done to assess the diagnostic potential of dual-source computed tomography (DSCT) in the functional evaluation of lung cancer patients undergoing surgical resection. The CT data were compared with pulmonary perfusion scintigraphy and pulmonary function tests (PFTs). MATERIALS AND METHODS All patients were evaluated with DSCT, scintigraphy and PFTs. The DSCT scan protocol was as follows: two tubes (80 and 140 kV; Care Dose protocol); 70 cc of contrast material (5 cc/s); 5- to 6-s scan time; 0.6 mm collimation. After the automatic calculation of lung perfusion with DSCT and quantification of air volumes and emphysema with dedicated software applications, the perfusional CT studies were compared with scintigraphy using a visual score for perfusion defects; CT air volumes and emphysema were compared with PFTs. RESULTS The values of accuracy, sensitivity, specificity and positive (PPV) and negative (NPV) predictive values of DSCT compared with perfusion scintigraphy as the reference standard were: 0.88, 0.84, 0.90, 0.93 and 0.88, respectively. The McNemar test did not identify significant differences either between the two imaging techniques (p=0.07) or between CT and PFTs (p=0.09). CONCLUSIONS DSCT is a robust and promising technique that provides important and accurate information on lung function.
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Okajima Y, Ohno Y, Washko GR, Hatabu H. Assessment of pulmonary hypertension what CT and MRI can provide. Acad Radiol 2011; 18:437-53. [PMID: 21377593 DOI: 10.1016/j.acra.2011.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/06/2011] [Accepted: 01/12/2011] [Indexed: 01/06/2023]
Abstract
RATIONALES AND OBJECTIVES Pulmonary hypertension (PH) is a life-threatening condition, characterized by elevated pulmonary arterial pressure, which is confirmed based on invasive right heart catheterization (RHC). Noninvasive examinations may support diagnosis of PH before proceeding to RHC and play an important role in management and treatment of the disease. Although echocardiography is considered a standard tool in diagnosis, recent advances have made computed tomography (CT) and magnetic resonance (MR) imaging promising tools, which may provide morphologic and functional information. In this article, we review image-based assessment of PH with a focus on CT and MR imaging. CONCLUSIONS CT may provide useful morphologic information for depicting PH and seeking for underlying diseases. With the accumulated technological advancement, CT and MRI may provide practical tools for not only morphologic but also functional assessment of patients with PH.
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Affiliation(s)
- Yuka Okajima
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Henzler T, Barraza JM, Nance JW, Costello P, Krissak R, Fink C, Schoepf UJ. CT imaging of acute pulmonary embolism. J Cardiovasc Comput Tomogr 2011; 5:3-11. [DOI: 10.1016/j.jcct.2010.10.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 10/05/2010] [Indexed: 02/07/2023]
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Initial experience of dual-energy lung perfusion CT using a dual-source CT system in children. Pediatr Radiol 2010; 40:1536-44. [PMID: 20596701 DOI: 10.1007/s00247-010-1759-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 05/10/2010] [Accepted: 05/14/2010] [Indexed: 12/13/2022]
Abstract
Initial experience of dual-source dual-energy (DE) lung perfusion CT in children is described. In addition to traditional identification of pulmonary emboli, the assessment of lung perfusion is technically feasible with dual-source DE CT in children with acceptable radiation dose. This article describes how to perform dual-source DE lung perfusion CT in children, including the optimization of intravenous injection method and CT dose parameters. How to produce weighted-average CT images for the assessment of pulmonary emboli and colour-coded perfusion maps for the assessment of regional lung perfusion is also detailed. Lung perfusion status can then be evaluated on perfusion maps by means of either qualitative or quantitative analysis. Potential advantages and disadvantages of this emerging CT technique compared to lung perfusion scintigraphy and cardiac MRI are discussed.
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Nagao M, Kido T, Watanabe K, Saeki H, Okayama H, Kurata A, Hosokawa K, Higashino H, Mochizuki T. Functional assessment of coronary artery flow using adenosine stress dual-energy CT: a preliminary study. Int J Cardiovasc Imaging 2010; 27:471-81. [PMID: 20686853 PMCID: PMC3092061 DOI: 10.1007/s10554-010-9676-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2010] [Accepted: 07/24/2010] [Indexed: 12/18/2022]
Abstract
We attempted to assess coronary artery flow using adenosine-stress and dual-energy mode with dual-source CT (DE-CT). Data of 18 patients with suspected coronary arteries disease who had undergone cardiac DE-CT were retrospectively analyzed. The patients were divided into two groups: 10 patients who performed adenosine stress CT, and 8 patients who performed rest CT as controls. We reconstructed an iodine map and composite images at 120 kV (120 kV images) using raw data with scan parameters of 100 and 140 kV. We measured mean attenuation in the coronary artery proximal to the distal portion on both the iodine map and 120 kV images. Coronary enhancement ratio (CER) was calculated by dividing mean attenuation in the coronary artery by attenuation in the aortic root, and was used as an estimate of coronary enhancement. Coronary stenosis was identified as a reduction in diameter of >50% on CT angiogram, and myocardial ischemia was diagnosed by adenosine-stress myocardial perfusion scintigraphy. The iodine map showed that CER was significantly lower for ischemic territories (0.76 ± 0.06) or stenosed coronary arteries (0.77 ± 0.06) than for non-ischemic territories (0.95 ± 0.21, P = 0.02) or non-stenosed coronary arteries (1.07 ± 0.33, P < 0.001). The 120 kV images showed no difference in CER between these two groups. Use of CER on the iodine map separated ischemic territories from non-ischemic territories with a sensitivity of 86% and a specificity of 75%. Our quantification is the first non-invasive analytical technique for assessment of coronary artery flow using cardiac CT. CER on the iodine map is a candidate method for demonstration of alteration in coronary artery flow under adenosine stress, which is related to the physiological significance of coronary artery disease.
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Affiliation(s)
- Michinobu Nagao
- Department of Molecular Imaging and Diagnosis, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka-City, Fukuoka 812-8582, Japan.
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Time-resolved and high-resolution MRA in a rabbit model of pulmonary embolism at 7 T: preliminary results. Magn Reson Imaging 2010; 28:139-45. [DOI: 10.1016/j.mri.2009.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 06/18/2009] [Accepted: 06/25/2009] [Indexed: 11/23/2022]
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Remy-Jardin M, Faivre JB, Pontana F, Hachulla AL, Tacelli N, Santangelo T, Remy J. Thoracic Applications of Dual Energy. Radiol Clin North Am 2010; 48:193-205. [DOI: 10.1016/j.rcl.2009.08.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zhang LJ, Zhao YE, Wu SY, Yeh BM, Zhou CS, Hu XB, Hu QJ, Lu GM. Pulmonary embolism detection with dual-energy CT: experimental study of dual-source CT in rabbits. Radiology 2009; 252:61-70. [PMID: 19561250 DOI: 10.1148/radiol.2521081682] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate feasibility and added value of dual-energy computed tomography (CT) in diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS This institutional animal experimental committee-approved study was performed in accordance with animal care guidelines. Eight New Zealand rabbits underwent standard unenhanced and contrast material-enhanced dual-source CT. Gelatin sponge particles were injected into the pulmonary artery, and rabbits underwent contrast-enhanced dual-source CT pulmonary angiography, from which blood-flow (BF) and fusion images were created. Immediately after dual-source CT, rabbits were sacrificed, their lungs were removed and fixed in 10% formalin, and detailed pathologic determination of location and number of lung lobes with PE was performed. Two rabbits were excluded: One died during the procedure. In the other, the catheter tip was retained in the left inferior pulmonary artery. This caused marked postembolization CT image artifacts in adjacent regions. Six rabbits were included in final analysis. Two radiologists without knowledge of pathologic results evaluated five pulmonary lobes in each rabbit and recorded whether PE was present. Pathologic results served as the reference standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the techniques were calculated. Weighted kappa values were calculated to evaluate agreement between modalities. RESULTS Pathologic analysis revealed PE in 18 of 30 pulmonary lobes. Conventional CT angiography was used to correctly identify PE in 12 lobes and absence of emboli in 18 lobes, which corresponded to sensitivity, specificity, PPV, and NPV of 67%, 100%, 100%, and 67%, respectively. A kappa value of 0.65 indicated good correlation with pathologic findings. On BF images, segments with an embolic region showed low perfusion compared with segments with a normal pulmonary region. BF images and fused images correctly showed PE in 16 of 18 pulmonary lobes and absence of emboli in 11 of 12 lobes, which corresponded to sensitivity, specificity, PPV, and NPV of 89%, 92%, 94%, and 85%, respectively, in detection of PE. A kappa value of 0.80 indicated good correlation with pathologic findings. CONCLUSION Dual-source CT can depict normal and abnormal blood perfusion distribution in a rabbit's lung. Abnormal pulmonary blood distribution, as shown at dual-source CT, improves detection of acute PE in rabbits.
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Affiliation(s)
- Long-Jiang Zhang
- Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Zhongshan East Rd 305, Xuanwu District, Nanjing, Jiangsu Province, China
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Cho SW, Kim IK, Kang JM, Song KW, Kim HS, Park CH, Yoo KJ, Kim BS. Evidence for in vivo growth potential and vascular remodeling of tissue-engineered artery. Tissue Eng Part A 2009; 15:901-12. [PMID: 18783324 DOI: 10.1089/ten.tea.2008.0172] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Nondegradable synthetic polymer vascular grafts currently used in cardiovascular surgery have no growth potential. Tissue-engineered vascular grafts (TEVGs) may solve this problem. In this study, we developed a TEVG using autologous bone marrow-derived cells (BMCs) and decellularized tissue matrices, and tested whether the TEVGs exhibit growth potential and vascular remodeling in vivo. Vascular smooth muscle-like cells and endothelial-like cells were differentiated from bone marrow mononuclear cells in vitro. TEVGs were fabricated by seeding these cells onto decellularized porcine abdominal aortas and implanted into the abdominal aortas of 4-month-old, bone marrow donor pigs (n = 4). Eighteen weeks after implantation, the dimensions of TEVGs were measured and compared with those of native abdominal aortas. Expression of molecules associated with vascular remodeling was examined with reverse transcription-polymerase chain reaction assay and immunohistochemistry. Eighteen weeks after implantation, all TEVGs were patent with no sign of thrombus formation, dilatation, or stenosis. Histological and immunohistochemical analyses of the retrieved TEVGs revealed regeneration of endothelium and smooth muscle and the presence of collagen and elastin. The outer diameter of three of the four TEVGs increased in proportion to increases in body weight and outer native aorta diameter. Considerable extents of expression of molecules associated with extracellular matrix (ECM) degradation (i.e., matrix metalloproteinase and tissue inhibitor of matrix metalloproteinase) and ECM precursors (i.e., procollagen I, procollagen III, and tropoelastin) occurred in the TEVGs, indicating vascular remodeling associated with degradation of exogenous ECMs (implanted decellularized matrices) and synthesis of autologous ECMs. This study demonstrates that the TEVGs with autologous BMCs and decellularized tissue matrices exhibit growth potential and vascular remodeling in vivo of tissue-engineered artery.
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Affiliation(s)
- Seung-Woo Cho
- Department of Bioengineering, Hanyang University, Seoul, Korea
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Pontana F, Faivre JB, Remy-Jardin M, Flohr T, Schmidt B, Tacelli N, Pansini V, Remy J. Lung perfusion with dual-energy multidetector-row CT (MDCT): feasibility for the evaluation of acute pulmonary embolism in 117 consecutive patients. Acad Radiol 2008; 15:1494-504. [PMID: 19000866 DOI: 10.1016/j.acra.2008.05.018] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 05/13/2008] [Accepted: 05/13/2008] [Indexed: 01/21/2023]
Abstract
RATIONALE AND OBJECTIVES To investigate the accuracy of dual-energy computed tomography in the depiction of perfusion defects in patients with acute pulmonary embolism (PE). MATERIALS AND METHODS One hundred seventeen consecutive patients with clinical suspicion of acute PE underwent dual-energy multidetector computed tomographic (CT) angiography of the chest with a standard injection protocol. Two radiologists evaluated, by consensus, the presence of endoluminal clots on (1) transverse "diagnostic" scans (contiguous 1-mm-thick averaged images from tubes A and B) and (2) lung perfusion scans. RESULTS Seventeen patients showed CT features of acute PE, with the depiction of 75 clots within the lobar (n = 15), segmental (n = 43) and subsegmental (n = 17) pulmonary arteries. A total of 17 clots were identified as complete filling defects (ie, obstructive clots), located within segmental (12 of 17) and subsegmental (5 of 17) arteries. Fourteen of the 17 obstructive clots were seen with the concurrent presence of corresponding perfusion defects, whereas cardiac motion and/or contrast-induced artifacts precluded the confident recognition of perfusion abnormalities in the remaining two segments and one subsegment. Four subsegmental perfusion defects were depicted without the visualization of endoluminal thrombi within the corresponding arteries. Perfusion defects were identified beyond five nonobstructive clots. CONCLUSION Simultaneous information on the presence of endoluminal thrombus and lung perfusion impairment can be obtained with dual-energy computed tomography.
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Suga K, Yasuhiko K, Iwanaga H, Tokuda O, Matsunaga N. Relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism: Assessment with breath-hold SPECT–CT pulmonary angiography fusion images. Eur J Radiol 2008; 67:472-80. [PMID: 17905552 DOI: 10.1016/j.ejrad.2007.08.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2007] [Revised: 08/15/2007] [Accepted: 08/22/2007] [Indexed: 11/21/2022]
Abstract
PURPOSE The relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism (PTE) was comprehensively assessed on deep-inspiratory breath-hold (DIBrH) perfusion SPECT-computed tomographic pulmonary angiography (CTPA) fusion images. MATERIALS AND METHODS Subjects were 34 acute PTE patients, who had successfully performed DIBrH perfusion SPECT using a dual-headed SPECT and a respiratory tracking system. Automated DIBrH SPECT-CTPA fusion images were used to assess the relation between lung perfusion defects and intravascular clots detected by CTPA. RESULTS DIBrH SPECT visualized 175 lobar/segmental or subsegmental defects in 34 patients, and CTPA visualized 61 intravascular clots at variable locations in 30 (88%) patients, but no clots in four (12%) patients. In 30 patients with clots, the fusion images confirmed that 69 (41%) perfusion defects (20 segmental, 45 subsegmental and 4 lobar defects) of total 166 defects were located in lung territories without clots, although the remaining 97 (58%) defects were located in lung territories with clots. Perfusion defect was absent in lung territories with clots (one lobar branch and three segmental branches) in four (12%) of these patients. In four patients without clots, nine perfusion defects including four segmental ones were present. CONCLUSION Because of unexpected dissociation between intravascular clots and lung perfusion defects, the present fusion images will be a useful adjunct to CTPA in the diagnosis of acute PTE.
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Affiliation(s)
- Kazuyoshi Suga
- Department of Radiology, St. Hill Hospital, 1462-3 Nishikiwa, Ube, Yamaguchi 755-0151, Japan.
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Abstract
Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled multi-detector row CT allow for quantification of presence and distribution of parenchymal and airway pathology; xenon gas can be employed to assess regional ventilation of the lungs, and rapid bolus injections of iodinated contrast agent can provide a quantitative measure of regional parenchymal perfusion. Advances in MRI of the lung include gadolinium-enhanced perfusion imaging and hyperpolarized gas imaging, which allow functional assessment, including ventilation/perfusion, microscopic air space measurements, and gas flow and transport dynamics.
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Affiliation(s)
- Edwin J R van Beek
- Department of Radiology, Carver College of Medicine, University of Iowa, C-751 GH, 200 Hawkins Drive, Iowa City, IA 52242-1077, USA.
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When to perform CTA in patients suspected of PE? Eur Radiol 2007; 18:500-9. [DOI: 10.1007/s00330-007-0768-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 07/30/2007] [Accepted: 08/28/2007] [Indexed: 10/22/2022]
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Remy-Jardin M, Pistolesi M, Goodman LR, Gefter WB, Gottschalk A, Mayo JR, Sostman HD. Management of suspected acute pulmonary embolism in the era of CT angiography: a statement from the Fleischner Society. Radiology 2007; 245:315-29. [PMID: 17848685 DOI: 10.1148/radiol.2452070397] [Citation(s) in RCA: 401] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Martine Remy-Jardin
- Department of Thoracic Imaging, Hospital Calmette, University Center of Lille, Boulevard Jules Leclerc, 59037, Lille, France.
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Ghaye B, Dondelinger RF. CT Diagnosis of Acute Pulmonary Embolism. Emerg Radiol 2007. [DOI: 10.1007/978-3-540-68908-9_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pech M, Wieners G, Dul P, Fischbach F, Dudeck O, Lopez Hänninen E, Ricke J. Computed tomography pulmonary embolism index for the assessment of survival in patients with pulmonary embolism. Eur Radiol 2007; 17:1954-9. [PMID: 17265051 DOI: 10.1007/s00330-007-0577-2] [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: 09/27/2005] [Revised: 12/11/2006] [Accepted: 01/08/2007] [Indexed: 10/23/2022]
Abstract
This study was an analysis of the correlation between pulmonary embolism (PE) and patient survival. Among 694 consecutive patients referred to our institution with clinical suspicion of acute PE who underwent CT pulmonary angiography, 188 patients comprised the study group: 87 women (46.3%, median age: 60.7; age range: 19-88 years) and 101 men (53.7%, median age: 66.9; age range: 21-97 years). PE was assessed by two radiologist who were blinded to the results from the follow-up. A PE index was derived for each set of images on the basis of the embolus size and location. Results were analyzed using logistic regression, and correlation with risk factors and patient outcome (survival or death) was calculated. We observed no significant correlation between the CTPE index and patient outcome (p = 0.703). The test of logistic regression with the sum of heart and liver disease or presence of cancer was significantly (p< 0.05) correlated with PE and overall patient outcome. Interobserver agreement showed a significant correlation rate for the assessment of the PE index (0.993; p< 0.001). In our study the CT PE index did not translate into patient outcome. Prospective larger scale studies are needed to confirm the predictive value of the index and refine the index criteria.
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Affiliation(s)
- Maciej Pech
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
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Ghaye B, Ghuysen A, Bruyere PJ, D'Orio V, Dondelinger RF. Can CT pulmonary angiography allow assessment of severity and prognosis in patients presenting with pulmonary embolism? What the radiologist needs to know. Radiographics 2006; 26:23-39; discussion 39-40. [PMID: 16418240 DOI: 10.1148/rg.261055062] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Computed tomographic (CT) pulmonary angiography has been established as a first-line diagnostic technique in patients suspected of having pulmonary embolism. Risk stratification is important in patients with pulmonary embolism because optimal management, monitoring, and therapeutic strategies depend on the prognosis. Acute right-sided heart failure is known to be responsible for circulatory collapse and death in patients with severe pulmonary embolism. Acute right-sided heart failure can be assessed at CT pulmonary angiography by measuring the dimensions of right-sided heart cavities or upstream venous structures, such as the superior vena cava or azygos vein. The magnitude of pulmonary embolism can be calculated at CT pulmonary angiography by applying angiographic scores adapted for CT (Miller and Walsh scores) or dedicated CT scores (Qanadli and Mastora scores). The advent of CT pulmonary angiography performed with electrocardiographic gating permits new advances in assessment of acute right-sided heart failure, such as measurement of the ventricular ejection fraction. Although such findings may be useful for assessment of treatment effectiveness, their effect on prognosis in patients with severe pulmonary embolism is debated in the literature.
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Affiliation(s)
- Benoît Ghaye
- Department of Medical Imaging, University Hospital of Liege, Sart Tilman B35, B-4000 Liege, Belgium.
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Dougherty L, Torigian DA, Affusso JD, Asmuth JC, Gefter WB. Use of an optical flow method for the analysis of serial CT lung images. Acad Radiol 2006; 13:14-23. [PMID: 16399029 DOI: 10.1016/j.acra.2005.09.081] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Revised: 09/02/2005] [Accepted: 09/04/2005] [Indexed: 11/18/2022]
Abstract
RATIONALE AND OBJECTIVES Serial CT lung studies are difficult to compare due to misregistration between image sets. An optical flow method (OFM) was adapted for use on CT lung images to register images and visualize changes between studies. Three applications were investigated: lung nodule assessment; evaluation of pulmonary enhancement; and functional changes due to air trapping. MATERIALS AND METHODS From an initial clinical study, a follow-up study was created by digitally manipulating the images to simulate patient positioning errors and nodule growth. Nodule growth was measured from the temporal subtraction of registered images. In application to the assessment of pulmonary enhancement, pre and postcontrast images from a patient with acute pulmonary embolism (PE) were registered. A map of the perfused blood volume was computed from the ratio of aligned lung volumes. Functional changes in the lung were demonstrated using images from a patient with air trapping. End-inspiratory and end-expiratory volumes were aligned and displacement fields estimated using the OFM. Principal strains were computed from the displacement fields. RESULTS All image volumes were aligned with at least 0.95 correlation. OFM estimates of displacement showed excellent agreement with the prescribed displacements with 0.33 pixel RMS error. Nodule growth was evident in the presence of significant positioning errors. In the PE case, enhancement ratios indicated a hypoperfused area consistent with an occlusive hypodense filling defect. For the air trapping case, a strain map showed functional changes along the interface of the air trap. CONCLUSIONS The OFM can facilitate the detection and quantification of changes between serial CT lung studies.
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Affiliation(s)
- Lawrence Dougherty
- Hospital of the University of Pennsylvania, Department of Radiology/1 Silverstein, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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