Pericarotid Fat as a Marker of Cerebrovascular Risk

Abstract

Vascular inflammation is widely recognized as an important factor in the atherosclerotic process, particularly in terms of plaque development and progression. Conventional tests, such as measuring circulating inflammatory biomarkers, lack the precision to identify specific areas of vascular inflammation. In this context, noninvasive imaging modalities can detect perivascular fat changes, serving as a marker of vascular inflammation. This review aims to provide a comprehensive overview of the key concepts related to perivascular carotid fat and its pathophysiology. Additionally, we examine the existing literature on the association of pericarotid fat with features of plaque vulnerability and cerebrovascular events. Finally, we scrutinize the advantages and limitations of the noninvasive assessment of pericarotid fat.

FIG 1.

Graphic overview of potential association of dysfunctional PCF.

FIG 2.

Examples of various methods described in the literature to define PCF. A, PCF is defined as the adipose tissue within a radial distance from the outer vessel wall equal to the diameter of the carotid vessel. B, PCF was obtained by tracking 2 separate regions of interest (each with an area of 2.5 mm²) located at least 1 mm from the outer margin of the carotid artery wall.

FIG 3.

Axial CT image of a 71-year-old-man with left ischemic stroke. Two ROIs were positioned in the PCF surrounding a stenotic left internal carotid artery with a vulnerable plaque (yellow circles), and 2 ROIs were placed in the contralateral carotid artery in the same section (white circles) to measure perivascular fat attenuation. The PCF demonstrates an HU value of 58.3 and 61 in the left carotid artery and 75.2 and 78.5 in the right carotid artery, respectively.