Neck-brain integrated ultrasound as a noninvasive screening tool to identify morphological features of middle cerebral artery disease

Abstract

Background and aims: Endovascular treatment is suitable for middle cerebral artery (MCA) with focal lesion. Therefore, accurate evaluation of the morphological features of MCA disease is critical. Ultrasonography is commonly used to screen for MCA lesions. However, there are few studies on lesion length. Using ultrasonography, we aimed to prospectively evaluate MCA disease with focal stenosis, long stenosis, focal occlusion, and long occlusion.

Methods: Patients with symptomatic MCA disease scheduled for digital subtraction angiography were enrolled. The ultrasonic parameters recorded included mean flow velocity at MCA (V_MCA) and extracranial internal carotid artery (V_ICA), bilateral V_MCA ratio, bilateral V_ICA ratio, and MCA flow continuity.

Results: A total of 278 MCAs were included. Compared to normal vessels, the bilateral V_MCA ratio increased in the focal stenosis group and decreased in the long lesion and focal occlusion groups (all p < 0.05); the V_ICA and bilateral V_ICA ratio decreased in the long lesion group (all p < 0.01), and there was no significant difference in the focal lesion group (all p > 0.05). The optimal cut-offs were bilateral V_MCA ratio <0.80 to predict long lesions and focal occlusions (sensitivity: 0.898, specificity: 0.975), and bilateral V_ICA ratio <0.84 to predict long lesions (sensitivity: 0.704, specificity: 0.879). The sensitivity and specificity to predict long occlusions were 96.7% and 94.8%, respectively, in the absence of MCA flow continuity.

Conclusions: Neck-brain integrated ultrasound is an appropriate screening method for identifying MCA lesions with different morphologies. Endovascular treatment might not be recommended when bilateral V_ICA ratio <0.84 in patients with MCA lesions.

Keywords: Intracranial atherosclerosis; Middle cerebral artery; Transcranial Doppler; Ultrasonography.