Quantification of carotid artery plaque and peri-vascular adipose tissue attenuation on computed tomography.

Aims: Quantitative assessment of carotid artery plaque on computed tomography (CT) may identify high-risk phenotypes associated with culprit lesions and subsequent ischaemic stroke or transient ischaemic attack.

Methods and results: Carotid CT angiography was performed in 48 patients with acute ischaemic stroke or transient ischaemic attack within 21 days. Quantitative plaque assessment was performed in the proximal 6 cm of the internal and external carotid artery, distal 6 cm of the common carotid artery, and residual common carotid artery. Semi-automated quantification included assessment of non-calcified, calcified, low-attenuation, and total plaque, area and diameter stenosis, and peri-vascular adipose tissue attenuation. In 48 patients (mean age 71 ± 11 years, 67% male), 96 vessels were assessed with 30 (31%) identified as culprit vessels. Culprit internal carotid arteries had greater area [83 (65, 94) vs. 64 (55, 77)%] and diameter [56 (39, 74) vs. 32 (21, 48)%] stenosis and more non-calcified [563 (413, 965) vs. 428 (283 649) mm³, P = 0.04], low-attenuation [33.7 (6.9, 72.4) vs. 16.3 (3.35, 54.3) mm³, P = 0.01], and total [699 (455, 1057) vs. 492 (311, 809), P = 0.04] plaque. There was no difference in calcified plaque or peri-vascular adipose tissue attenuation between culprit and non-culprit internal carotid arteries. There were no differences in quantitative plaque or peri-vascular adipose tissue attenuation in the external carotid artery or common carotid artery.

Conclusion: Carotid atherosclerotic plaque characteristics are the principal features associated with culprit plaques with little or no demonstrable relationship with calcified plaque or increased peri-vascular adipose tissue attenuation.