Multiparametric flow analysis using four-dimensional flow magnetic resonance imaging can detect cerebral hemodynamic impairment in patients with internal carotid artery stenosis

Purpose MRI-based risk stratification should be established to identify patients with internal carotid artery stenosis (ICS) who require further PET or SPECT evaluation. This study assessed whether multiparametric flow analysis using time-resolved 3D phase-contrast (4D flow) MRI can detect cerebral hemodynamic impairment in patients with ICS. Methods This retrospective study analyzed 26 consecutive patients with unilateral ICS (21 men; mean age, 71 years) who underwent 4D flow MRI and acetazolamide-stress brain perfusion SPECT. Collateral flow via the Willis ring was visually evaluated. Temporal mean flow volume rate (Net), pulsatile flow volume (Δ V ), and pulsatility index (PI) at the middle cerebral artery were measured. Cerebral vascular reserve (CVR) was calculated from the SPECT dataset. Patients were assigned to the misery perfusion group if the CVR was < 10% and to the nonmisery perfusion group if the CVR was ≥ 10%. Parameters showing a significant difference in both groups were statistically evaluated. Results Affected side Δ V , ratio of affected to contralateral side Net (rNet), and ratio of affected to contralateral side Δ V were significantly correlated to CVR ( p = 0.030, p = 0.010, p = 0.015, respectively). Absence of retrograde flow at the posterior communicating artery was observed in the misery perfusion group ( p = 0.020). Combined cut-off values of the affected side Δ V (0.18 ml) and rNet (0.64) showed a sensitivity and specificity of 100% and 77.8%, respectively. Conclusion Multiparametric flow analysis using 4D flow MRI can detect misery perfusion by comprehensively assessing blood flow data, including blood flow volume, pulsation, and collateral flow.