Imaging Atherosclerotic Plaques by Cardiac Computed Tomography In Vitro (original) (raw)
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World journal of radiology, 2012
To assess the attenuation of non-calcified atherosclerotic coronary artery plaques with computed tomography coronary angiography (CTCA). Four hundred consecutive patients underwent CTCA (Group 1: 200 patients, Sensation 64 Cardiac, Siemens; Group 2: 200 patients, VCT GE Healthcare, with either Iomeprol 400 or Iodixanol 320, respectively) for suspected coronary artery disease (CAD). CTCA was performed using standard protocols. Image quality (score 0-3), plaque (within the accessible non-calcified component of each non-calcified/mixed plaque) and coronary lumen attenuation were measured. Data were compared on a per-segment/per-plaque basis. Plaques were classified as fibrous vs lipid rich based on different attenuation thresholds. A P < 0.05 was considered significant. In 468 atherosclerotic plaques in Group 1 and 644 in Group 2, average image quality was 2.96 ± 0.19 in Group 1 and 2.93 ± 0.25 in Group 2 (P ≥ 0.05). Coronary lumen attenuation was 367 ± 85 Hounsfield units (HU) in G...
The International Journal of Cardiovascular Imaging, 2013
Computed tomography (CT) may characterize lipid-rich and presumably rupture-prone non-calcified coronary atherosclerotic plaque based on its Hounsfield-Unit (HU), but still inconclusively. This study aimed to evaluate factors influencing the HU-value of non-calcified plaque using software simulation. Several realistic virtual plaqueburdened coronary phantoms were constructed at 5 lm resolution. CT scanning was simulated with settings resembling a 64-row multi-detector CT (64-MDCT) and reconstructed at 64-MDCT (0.4 mm) and MicroCT (48 lm) resolutions. Influences of lumen contrastenhancement, stenosis-grades, and plaque compositions on plaque visualization were analyzed. Lumen contrastenhancement and mean plaque HU-value were positively correlated (R 2 [ 0.92), with approximately the same slopes for all plaque compositions. Percentage lipid-content and mean plaque HU-value were negatively correlated (R 2 [ 0.98). Stenosis-grade and noise had minimal influence on the correlations. Influence of lumen contrastenhancement on plaque HU-value was following a specific exponentially declining pattern (y = Ae -kx ? c) from the lumen border until 2-pixel radius. Outside 2-pixel radius, plaque HU-values deviated maximally 5 HU from noncontrast-enhanced reference. Thus, to avoid lumen contrast-enhancement influence, plaques should be measured outside 2-pixel radius from the lumen border. Based on the patterns found, a lumen influence correction algorithm may be developed. HU-based plaque percentage lipid-content determination might serve as an alternative plaque characterization method. However, its applicability is still hindered by many inherent limitations.
British Journal of Radiology, 2012
Objective: To compare the influence of different iodinated contrast media with several dilutions on plaque attenuation in an ex vivo coronary model studied by multislice CT coronary angiography. Methods: In six ex vivo left anterior descending coronary arteries immersed in oil, CT (slices/collimation 6460.625 mm, temporal resolution 210 ms, pitch 0.2) was performed after intracoronary injection of a saline solution, and solutions of a dimeric isosmolar contrast medium (Iodixanol 320 mgI ml 21 ) and a monomeric high-iodinated contrast medium (Iomeprol 400 mgI ml 21 ) with dilutions of 1/80 (low concentration), 1/50 (medium concentration), 1/40 (high concentration) and 1/20 (very high concentration). Two radiologists drew regions of interest in the lumen and in calcified and noncalcified plaques for each solution. 29 cross-sections with non-calcified plaques and 32 cross-sections with calcified plaques were evaluated. Results: Both contrast media showed different attenuation values within lumen and plaque (p,0.0001). The correlation between lumen and non-calcified plaque values was good (Iodixanol r50.793, Iomeprol r50.647). Clustered medium-and high-concentration solutions showed similar plaque attenuation values, signal-to-noise ratios (SNRs) (noncalcified plaque: medium solution SNR 31.3¡15 vs 31.4¡20, high solution SNR 39.4¡17 vs 37.4¡22; calcified plaque: medium solution SNR 305.2¡133 vs 298.8¡132, high solution SNR 323.9¡138 vs 293¡123) and derived contrast-to-noise ratios (p.0.05). Conclusion: Differently iodinated contrast media have a similar influence on plaque attenuation profiles. Advances in knowledge: Since iodine load affects coronary plaque attenuation linearly, different contrast media may be equally employed for coronary atherosclerotic plaque imaging. , et al. Comparison of iodinated contrast media for the assessment of atherosclerotic plaque attenuation values by CT coronary angiography: observations in an ex vivo model. Br J Radiol 2013;86:20120238. Br J Radiol, 86, 20120238 1 of 7 Influence of iodinated CM on atherosclerotic plaque imaging by CTCA Br J Radiol, 86, 20120238
Quantitative plaque characterization with coronary CT angiography (CTA)
The International Journal of …, 2008
In the current issue of the journal, Knollmann et al. describe results from a quantitative post-mortem coronary plaque analysis with CT angiography (CTA) in comparison to histology . Plaque burden was quantified on a per-segment and a per-patient basis and demonstrated an overall fair correlation to histology, but significant overestimation with CT. Further analysis of calcified and non-calcified plaque components demonstrated best correlation for calcified plaque with overestimation of plaque burden. In contrast, there was relatively poor correlation for non-calcified plaque components and in particular the lipid core area, which was underestimated with CT in comparison to histology. Importantly, the correlation was better for patient-based analysis (average of all segments) versus segment-based analysis. For segment-based analysis of individual plaques the correlation between histology and CT was limited for small plaques.
Ex vivo coronary atherosclerotic plaque characterization with multi-detector-row CT
European Radiology, 2003
Multi-detector-row CT angiography (CTA) is a new technology that allows for non-invasive investigation of coronary atherosclerosis in patients. The relation between the morphology of atherosclerotic plaques assessed by CTA and histopathology is unknown. We investigated 11 human cadaver heart specimens. A mixture of methylcellulose and CT contrast media was injected into the coronary arteries to achieve in-vivo-like contrast enhancement within the coronary artery lumen. The morphologic pattern of atherosclerotic lesions found on CTA images and the tissue attenuation of non-calcified plaques were determined. After CTA imaging, atherosclerotic lesions in the coronary arteries were macroscopically identified and characterized histopathologically according to American Heart Association criteria. A total of 50 and 40 lesions were found macroscopically and by CTA, respectively. Thirty-three lesions could have been compared directly. The sensitivity of CTA compared with macroscopic detection of atheromas, fibroatheromas, fibrocalcified, and calcified lesions was 73, 70, 86, and 100%, respectively. The mean CT attenuation of predominantly lipid-rich and fibrous-rich plaques was significantly different (47±9 and 104±28 HU, respectively; p<0.01). Atherosclerotic coronary plaques detected by CTA may represent different stages of coronary atherosclerosis. The tissue attenuation of non-calcified plaques may allow for assessment of their predominant component.
Coronary CT angiography in the quantitative assessment of coronary plaques
BioMed research international, 2014
Coronary computed tomography angiography (CCTA) has been recently evaluated for its ability to assess coronary plaque characteristics, including plaque composition. Identification of the relationship between plaque composition by CCTA and patient clinical presentations may provide insight into the pathophysiology of coronary artery plaque, thus assisting identification of vulnerable plaques which are associated with the development of acute coronary syndrome. CCTA-generated 3D visualizations allow evaluation of both coronary lesions and lumen changes, which are considered to enhance the diagnostic performance of CCTA. The purpose of this review is to discuss the recent developments that have occurred in the field of CCTA with regard to its diagnostic accuracy in the quantitative assessment of coronary plaques, with a focus on the characterization of plaque components and identification of vulnerable plaques.
2011
Purpose. The authors assessed the effect of vascular attenuation and density thresholds on the classification of noncalcified plaque by computed tomography coronary angiography (CTCA). Materials and methods. Thirty patients (men 25; age 59±8 years) with stable angina underwent arterial and delayed CTCA. At sites of atherosclerotic plaque, attenuation values (HU) were measured within the coronary lumen, noncalcified and calcified plaque material and the surrounding epicardial fat. Based on the measured CT attenuation values, coronary plaques were classified as lipid rich (attenuation value below the threshold) or fibrous (attenuation value above the threshold) using 30-HU, 50-HU and 70-HU density thresholds. Results. One hundred and sixty-seven plaques (117 mixed and 50 noncalcified) were detected and assessed. The attenuation values of mixed plaques were higher than those of exclusively noncalcified plaques in both the arterial (148.3±73.1 HU vs. 106.2±57.9 HU) and delayed (111.4±50.5 HU vs. 64.4±43.4 HU) phases (p<0.01). Using a 50-HU threshold, 12 (7.2%) plaques would be classified as lipid rich on arterial scan compared with 28 (17%) on the delayed-phase scan. Reclassification of these 16 (9.6%) plaques from fibrous to lipid rich involved 4/30 (13%) patients. Riassunto Obiettivo. Scopo del presente lavoro è valutare l'effetto dell'attenuazione vascolare e delle soglie di densità sulla classificazione delle placche aterosclerotiche coronariche non calcifiche mediante angiografia coronarica con tomografia computerizzata (CTCA). Materiali e metodi. Trenta pazienti (maschi 25; età 59±8 anni) con angina stabile sono stati sottoposti a CTCA in fase arteriosa e tardiva. Nei segmenti con aterosclerosi coronarica, è stata misurata l'attenuazione (HU) del lume coronarico, delle componenti calcifica e non calcifica delle placche aterosclerotiche e del tessuto adiposo epicardico adiacente. Sulla base delle attenuazioni misurate, le placche sono state classificate come lipidiche (valori di attenuazione al di sotto della soglia) o fibrose (valori di attenuazione al di sopra della soglia) utilizzando 30 HU, 50 HU e 70 HU come soglie di densità. Risultati. Sono state rilevate e valutate 167 placche (117 miste e 50 non calcifiche). I valori di attenuazione della placche miste è risultato maggiore di quello delle placche esclusivamente non calcifiche, sia in fase arteriosa (148,3±73,1 HU vs. 106,2±57,9 HU) che in fase tardiva (111,4±50,5 HU vs. 64,4±43,4 HU; p<0,01). Utilizzando una soglia di 50 HU, 12 (7,2%) placche sarebbero state classificate come lipidiche nella fase arteriosa, contro 28 (17%) nella fase tardiva. La riclassificazione di queste 16