The Estimation of Hemodynamic Significant Deformations of Brachiocephalic Arteries Using CT-perfusion

Background and Aim: The cause of most strokes is associated with the pathology of the carotid arteries. Many modern researchers suggest preventive surgery in the presence of arterial deformity to prevent stroke. The hemodynamic significance of carotid deformities is determined by morphological and functional disorders at the level of tortuosity, while the reaction of cerebral blood flow is not taken into account. We assume that the cerebral autoregulation in tortuosity may differ. Methods and Materials/Patients: Sixty-four patients (۳۱-۷۵ years old) with ۱۱۰ carotid deformities were analyzed. Duplex color mapping, CT-angiography of carotid arteries, and  CT-perfusion (CTP) were performed with the estimation of absolute and average values ​​of cerebral blood flow (CBF, ml/۱۰۰g/min), cerebral blood volume (CBV, ml/۱۰۰g), mean transit time (MTT, s) in similar areas of the cortex. In ۶ patients, the acetazolamide (ACZ) challenge test was used to evaluate the autoregulatory disturbances. All findings were calculated statistically. Results: According to CT angiography and Duplex color mapping, ۱۸ patients had unilateral tortuosity (۲۸.۱%), and ۴۶ patients had bilateral tortuosity (۷۱.۹%). Hemodynamically significant deformities were detected in ۳۳ cases (۳۰% of tortuosities), and in ۵۴ cases (۴۹% of tortuosities), the deformities were accompanied by carotid stenosis. Perfusion disorders were detected in ۲۳ of ۶۴ patients (۳۵.۹%). In the majority of cases (۷۵% of all perfusion disorders), hypoperfusion was diagnosed on the side corresponding to the maximum degree of stenosis, regardless of the location of the tortuosity. Neurologically significant hypoperfusion, compensated by collateral blood flow was revealed only in ۷.۸% of cases of hemodynamic significant ICA deformity without concomitant atherosclerosis.  Conclusion: The obtained data suggest that the decision on surgical correction of carotid artery tortuosity should be made taking into account both local changes in hemodynamics and proven violations of autoregulation of cerebral blood flow, especially in patients with concomitant carotid stenosis.

Keywords:

CT-angiography , CT-Perfusion , Brachiocephalic Arteries , Tortuosity