Background and purpose: To assess the clinical feasibility of time-resolved 3D phase contrast (4D Flow) MRI assessment of the ophthalmic artery (OphA) flow in patients with internal carotid artery stenosis (ICS).
Materials and methods: Twenty-one consecutive patients with unilateral ICS were recruited. 4D Flow MRI and acetazolamide-stress brain perfusion single photon emission computed tomography (SPECT) were performed. The flow direction on the affected-side OphA was categorized into native flow (anterograde or unclear) and non-native flow (retrograde flow) based on 4D Flow MRI. In the affected-side middle cerebral artery (MCA) territory, the ratio of rest cerebral blood flow to normal control (RCBFMCA) and cerebral vascular reserve (CVRMCA) were calculated from SPECT dataset. High-risk patients were defined based on the previous large cohort study (RCBFMCA < 80% and CVRMCA < 10%).
Results: Eleven patients had native OphA flow (4 anterograde, 7 unclear) and the remaining 10 had non-native OphA flow. RCBFMCA and CVRMCA each were significantly lower in non-native flow group (84.9 ± 18.9% vs. 69.8 ± 7.3%, P < 0.05; 36.4 ± 20.6% vs. 17.0 ± 15.0%, P < 0.05). Four patients in the non-native flow group and none in the native flow group were confirmed as high-risk (Sensitivity/Specificity, 1.00/0.65).
Conclusion: The 6 min standard 4D Flow MRI assessment of OphA in patients with ICS can predict intracranial hemodynamic impairment.
Keywords: Single Photon Emission Computed Tomography; atherosclerosis; magnetic resonance angiography; ophthalmic artery; time-resolved three-dimensional phase contrast.