Iranian Journal of Neurosurgery (Jan 2023)
Estimating Hemodynamic Significant Deformations of Brachiocephalic Arteries Using CT Perfusion
Abstract
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 strokes. The hemodynamic significance of carotid deformities is determined by morphological and functional disorders at the level of tortuosity, the reaction of cerebral blood flow is not often considered. Here, we assume that cerebral autoregulation in tortuosity can be different. Methods and Materials/Patients: A total of 64 patients (31-75 years old) with 110 carotid deformities were analyzed. Duplex color mapping, computed tomography angiography of carotid arteries, and computed tomography perfusion were performed by estimating the absolute and average values of cerebral blood flow (mL/100 g/min), cerebral blood volume (mL/100 g), Mean transit time (MTT) (s) in similar areas of the cortex. In 6 patients, the acetazolamide challenge test was used to evaluate the autoregulatory disturbances. Results: According to computed tomography angiography and duplex color mapping, 18(28.1%) patients had unilateral tortuosity, and 46(71.9%) patients had bilateral tortuo s ity. Hemodynamically significant deformities were detected in 33 cases (30% of tortuosity). In 54 cases (49% of tortuosity), the deformities were accompanied by carotid stenosis. Perfusion disorders were detected in 23 of 64 patients (35.9%). In the majority of cases (75% 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 revealed only in 7.8% of cases of hemodynamic significant internal carotid artery deformity without concomitant atherosclerosis. Conclusion: The decision on surgical correction of carotid artery tortuosity should be made while considering both local changes in hemodynamics and proven violations of autoregulation of cerebral blood flow, especially in patients with concomitant carotid stenosis.
