Standardized volumetric plaque quantification and characterization from coronary CT angiography: a head-to-head comparison with invasive intravascular ultrasound

Abstract

Objectives-We sought to evaluate the accuracy of standardized total plaque volume (TPV) measurement and low-density non-calcified plaque (LDNCP) assessment from coronary CT angiography (CTA) in comparison with intravascular ultrasound (IVUS).Methods-We analyzed 118 plaques without extensive calcifications from 77 consecutive patients who underwent CTA prior to IVUS. CTA TPV was measured with semi-automated software comparing both scan-specific (automatically derived from scan) and fixed attenuation thresholds. From CTA, %LDNCP was calculated voxels below multiple LDNCP thresholds (30, 45, 60, 75, and 90 Hounsfield units [HU]) within the plaque. On IVUS, the lipid-rich component was identified by echo attenuation, and its size was measured using attenuation score (summed Hidenari Matsumoto,

Extraction of Coronary Atherosclerotic Plaques From Computed Tomography Imaging: A Review of Recent Methods

“…In vivo data were used in the majority (14 out of 17) of the original studies on 3D plaque extraction ( 28 , 30 , 32 , 33 , 47 , 51 – 56 , 62 , 64 ) and was mentioned in the review paper [( 63 ) in ( 72 )]. With 3D reconstruction, the diversity in the geometry and composition of plaques could be fully disclosed and represented not only on cross-sections but also in the longitudinal direction along the vessel, as well as in volume.…”

“…In another study, to investigate the difference between proximal and distal segments of the main coronary arteries [anterior descending artery (LAD), left circumflex artery (LCX), right coronary artery (RCA)], the middle segments and side branches were excluded ( 32 ). In some studies, arterial segments especially distal branches were excluded due to low quality of images ( 30 , 54 ).…”

“…The plaques could be classified according to the main component as soft lipid-rich plaques, mixed plaques, and calcified plaques ( 55 ), or non-calcified plaques, low-density non-calcified plaques, and calcified plaques ( 56 ). The volume of extracted component heavily depends on the threshold of attenuation value applied in the study ( 30 ).…”

“…As shown in Table 3 , in 3D plaque extraction, 130 HU was used as the lower threshold of calcified plaques ( 28 ) similar as in 2D studies, while higher attenuation values such as 400 HU ( 47 ) and 500 HU ( 30 ) were also observed. For non-calcified plaques, the 3D reconstruction studies provided more details on the separation between lipid-rich and fibrous plaques.…”

“…For non-calcified plaques, the 3D reconstruction studies provided more details on the separation between lipid-rich and fibrous plaques. Matsumoto et al used different thresholds attenuation (30 and 45 HU) to extract low-density non-calcified plaques ( 30 ), and concluded that the upper threshold of 45 HU improved the accuracy of lipid-rich plaque assessment from CTA.…”