Association between spontaneous internal carotid artery dissection and perivascular adipose tissue attenuation on computed tomography angiography

Abstract

Background: Spontaneous cervical artery dissection (sCAD) is a leading cause of ischemic stroke in young patients. Studies using high-resolution magnetic resonance imaging and positron emission tomography have suggested vessel wall inflammation to be a pathogenic factor in sCAD. Computed tomography (CT) attenuation of perivascular adipose tissue (PVAT) is an established non-invasive imaging biomarker of inflammation in coronary arteries, with higher attenuation values reflecting a greater degree of vascular inflammation. Objectives: We evaluate the CT attenuation of PVAT surrounding the internal carotid artery (PVAT<sub>carotid</sub>) with and without spontaneous dissection. Methods: Single-centre prospective observational study of 56 consecutive patients with CT-verified spontaneous dissection of the internal carotid artery (ICA) admitted between 2011 and 2018. Of these patients, 6 underwent follow-up CTA. 22 patients who underwent CTA for acute neurological symptoms but did not have dissection formed the control group. Using semiautomated research software, PVAT<sub>carotid</sub> was measured as the mean Hounsfield Unit (HU) attenuation of adipose tissue within a defined volume of interest surrounding the ICA. Results: PVAT<sub>carotid</sub> was significantly higher around dissected ICA compared with non-dissected contralateral ICA in the same patients (-58.7±10.2 vs. -68.9±8.1 HU, P<0.0001) and ICA of patients without dissection (-58.7±10.2 vs. -69.3±9.3 HU, P<0.0001). After a median follow-up of 89 days, there was a significant reduction in PVAT<sub>carotid</sub> around dissected ICA (from -57.5±13.4 to -74.3±10.5 HU, P<0.05); while no change was observed around non-dissected contralateral ICA (from -71.0±4.4 to -74.1±4.1 HU, P=0.19). ICA dissection was an independent predictor of PVAT<sub>carotid</sub> following multivariable adjustment for age and the presence of ICA occlusion. Conclusion: PVAT<sub>carotid</sub> is elevated in the presence of sCAD and may decrease following the acute event.

Cardiovascular Disease from Pathophysiology to Risk Estimation: Is Inflammation Estimated through Perivascular Attenuation on Computed Tomography the Key?

“…A higher PVAT on stenotic internal carotid artery was associated with the presence of cerebrovascular symptoms in patients with transient ischemic attack or non-cardioembolic ischemic stroke. Furthermore, the PVAT applied on the internal carotid artery with spontaneous dissection is greater than on the contralateral vessel in the same subject [20][21][22].…”

“…Plaques with symptoms (−55.0 ± 10.0 HU) had a higher pericarotid fat density than those without symptoms (−68.0 ± 10.3 HU, p < 0.0001). [22] Association between spontaneous internal carotid artery dissection and perivascular adipose tissue attenuation on computed tomography angiography. [23]…”