Correlation of Atherosclerotic Plaque Compositions in Coronary and Carotid Arteries

Introduction: Atherosclerosis has been shown to be a systematic disease which often involves multiple vascular beds, such as coronary and carotid arteries . The size of carotid lipid-rich necrotic core (LRNC) and presence of intraplaque hemorrhage (IPH) were demonstrated to be high risk features due to their correlations with neurovascular events . For coronary atherosclerosis, previous studies suggest that coronary mixed type of atherosclerotic plaques may be vulnerable lesions prone to developing cardiac events . These studies indicate that the assessment of plaque compositional features in both coronary and carotid arteries is necessary. Recently, a number of studies demonstrated a significant correlation between coronary and carotid atherosclerosis . However, the association of coronary and carotid plaque compositions is unknown. Purpose: This study sought to determine the correlation of atherosclerotic plaque compositions between coronary and carotid arteries using CT and MRI. Methods: One hundred and twenty-three subjects (mean age 58 years, 96 males) with suspected coronary artery disease underwent coronary CT angiography (CTA) on a Siemens Dual Source CT and carotid MR imaging on a GE 3.0T MR scanner within 2 weeks interval. Coronary CTA imaging parameters were as follows: 64× 0.6 mm, 0.33s/rot, 120 kV, 350 mAs, pitch 0.20-0.28, reconstructed image slice thickness 0.75mm with 0.5mm slice spacing on 60-80% RR interval. Contrast media (Iomeprol 370mg I/ml, Bracco) was injected intravenously with bolus of 70ml at 5 ml/s. A standardized multi-contrast protocol [6] was used to perform carotid MR imaging with the following parameters: T1w, quadruple inversion-recovery, TR/TE 800/8.8ms; Double IR, TR/TE 3000/13.1ms for PDw and 3000/56.9 ms for T2w; and 3D TOF: TR/TE 29/2.1ms, flip angle 20°. MR images were acquired with 2 mm slice thickness, field of view of 14 cm, and matrix size 256×256. Coronary plaques were classified into three types: non-calcified, calcified, and mixed type plaques . The presence /absence of three types of plaques and plaque scores (plaque number) for three types of plaques were evaluated for each subject. Presence/absence and the volume of calcification (CA), LRNC and IPH were indentified and measured by two trained reviewers with consensus blinded to coronary CT images using a custom designed software (CASCADE , Seattle, WA, USA). The three types of coronary plaque scores in patients with and without carotid CA, LRNC, and IPH were compared. The Volumes of carotid CA, LRNC, and IPH in subjects with and without coronary non-calcified, calcified, and mixed type plaques were also compared. ROC analysis was used to determine the AUC of coronary plaque scores for classifying presence of carotid CA, LRNC, and IPH. In addition, the AUC of carotid CA, LRNC, and IPH volume for classifying coronary different type of plaque were also analyzed. Results: Subjects with carotid CA or LRNC showed significantly larger coronary three types of plaque scores than those without carotid plaque compositions (Table 1). Significant difference can be found for coronary mixed type plaque score only in subjects with and without carotid IPH (Table 1). For subjects with and without coronary non-