Can 3D Pseudo-Continuous Territorial Arterial Spin Labeling Effectively Diagnose Patients With Recanalization of Unilateral Middle Cerebral Artery Stenosis?

Abstract

Background: Unilateral middle cerebral artery (MCA) stenosis, as an independent risk factor for stroke, requires an intervention operation for vessel recanalization. Accurate perfusion measurement is thus essential after the operation.

Purpose: To explore the feasibility of three-dimensional (3D) pseudo-continuous territorial arterial-spin-labeling (tASL) in evaluating MCA recanalization.

Study type: Prospective and longitudinal.

Subjects: Forty-seven patients with unilateral MCA stenosis or occlusion.

Field strength/sequence: A 3.0 T, 3D time-of-flight fast-field-echo magnetic resonance (MR) angiography sequence, spin-echo echo-planar diffusion-weighted imaging sequence, 3D fast-spin-echo pseudo-continuous ASL (pcASL) and tASL sequences.

Assessment: All patients underwent MR examination before and after MCA recanalization and scored using the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) at admission and discharge. An mRS score <2 was defined as a good prognosis. 3D-pcASL and tASL cerebral blood flow (CBF) maps were obtained, and the corresponding Alberta Stroke Program Early CT Score (ASPECTS)-based scores were evaluated.

Statistical tests: The Kolmogorov-Smirnov test, intra-class correlation coefficient, paired t-test, receiver operating characteristic (ROC) curve, and multivariable logistic regression analysis.

Results: After recanalization, tASL derived absolute CBFs between the affected and contralateral sides were significantly higher than before the operation (mean: 34.3 ± 8.5 mL/100 g/min vs. 40.6 ± 9.2 mL/100 g/min, 42.6 ± 9.8 mL/100 g/min vs. 43.5 ± 9.9 mL/100 g/min, both P < 0.05). In ROC analysis, tASL provided good prognosis (area under ROC curve [AUC] = 0.829; 95% CI: 0.651-1.000, P < 0.05), while pcASL had lower prognostic value (AUC = 0.760; 95% CI: 0.574-0.946, P < 0.05). The NIHSS score before recanalization, pcASL, and tASL-based ASPECTS scores were significantly associated with good clinical outcome (P < 0.05). Multivariable analysis revealed that ASPECTS-based scores of pcASL and tASL before and after surgery were independent predictors of good clinical outcome (all P < 0.05). DATA CONCLUSION: tASL can determine hypoperfusion in the responsible vascular perfusion area and predict clinical outcome.

Evidence level: 4 TECHNICAL EFFICACY: Stage 2.

Keywords: arterial spin labeling; cerebral blood flow; middle cerebral artery; perfusion imaging; revascularization surgery; territorial arterial spin labeling.