Influence of intracoronary attenuation on coronary plaque measurements using multislice computed tomography: observations in an ex vivo model of coronary computed tomography angiography

Abstract

Influence of intracoronary attenuation on coronary plaque measurements using multislice computed tomography: observations in an ex vivo model of coronary computed tomography angiography Abstract Assessment of attenuation (measured in Hounsfield units, HU) of human coronary plaques was performed using multislice computed tomography (MSCT) in an ex vivo model. In three ex vivo specimens of left coronary arteries in oil, MSCT was performed after intracoronary injection of four solutions of contrast material (400 mgI/ml iomeprol). The four solutions were diluted as follows: 1/∞, 1/200, 1/80, and 1/20. All scans were performed with the following parameters: slices/collimation 16/0.75 mm, rotation time 375 ms. Each specimen was scored for the presence of atherosclerotic plaques. In each plaque the attenuation was measured in four regions of interest for lumen, plaque (non-calcified thickening of the vessel wall), calcium, and surrounding (oil surrounding the vessel). The results were compared with a one-way analysis of variance test and were correlated with Pearson's test. There were no significant differences in the attenuation of calcium and oil in the four solutions. The mean attenuation in the four solutions for lumen (35±10, 91±7, 246±18, 511±89 HU) and plaque (22±22, 50±26, 107±36, 152±67 HU) was significantly different between each decreasing dilution (p<0.001). The mean attenuation of lumen and plaque of coronary plaques showed high correlation, while the values were significantly different (r=0.73; p<0.001). Intracoronary attenuation modifies significantly the attenuation of plaques assessed with MSCT.

Comparison of 64-Slice Multidetector Computed Tomography With Spectral Analysis of Intravascular Ultrasound Backscatter Signals for Characterizations of Noncalcified Coronary Arterial Plaques

“…However, there are wide distributions of CT densities among studies, which may be attributed mainly to differences in contrast flow rate between studies. Schroeder et al 11 and Cademartiri et al 12 demonstrated that an ex vivo model that contrasts flow rate and contrast concentration within the coronary artery may affect density measurement. In addition, small microcalcification within the plaque, which was frequently found around the necrotic core and not grossly visualized on multidetector computed tomogram, may have affected density measurement through partial volume and beam-hardening effects.…”

Detection of Attenuated Plaque in Stable Angina With 64-Multidetector Computed Tomography

“…6 However, it is considered that the large variability of these measurements makes for an accurate classification of non-calcified 'plaque types' difficult. 19, 20 Recently, 1 criterium for soft plaque was reported to be a CT density value <30 HU. 17 Accordingly, our results indicating that the portions without a HDA in attenuated plaque included areas <30 HU, might support the hypothesis that lipid-laden atheroma is one of the components of attenuated plaque.…”

Coronary Plaque Stabilization Followed by Color Code PlaqueTM Analysis With 64-Slice Multidetector Row Computed Tomography

“…As the concept is based on the CT value, the plaque CT value is influenced by contrast media density in the vessel lumen, 13 calcium blooming effects and motion artifacts. In the present case, the evaluation of plaque with CCP was considered to be correct, because both lumen CT values (approximately 300 HU) at the reference sites of the first and second CCP examination were similar and only slightly affected by those of the plaques (Figures 1,3).…”