Abstract TP119: Feasibility of Automated Analysis of Dual- Venc 4d Flow Mri to Assess Hemodynamics in Patients With Intracranial Atherosclerotic Disease

Abstract

Purpose: Advanced imaging and automated image processing techniques were used to demonstrate the feasibility of 4D flow MRI as a clinical tool for assessment of intracranial hemodynamics in patients with intracranial atherosclerotic disease (ICAD). Introduction: ICAD patients have a high risk of stroke recurrence, which could be partly due to intracranial hemodynamic failure. Thus, it is critical to assess the impact of ICAD on cerebrovascular flow dynamics. Dual- venc 4D flow MRI allows the assessment of flow in major intracranial arteries and veins by providing a large dynamic range. A new automated post-processing tool was developed to ease the cumbersome processing task that hinders clinical application of 4D flow MRI. Method: Intracranial dual- venc 4D flow MRI (Fig 1a) was acquired in 20 healthy volunteers (12M, 43±18Y) and three ICAD patients: two men, 65Y with near occlusion and 43Y with 65% stenotic right MCAs and a 70Y woman with stenoses in PCAs and ACAs (> 50%). Post-processing included automated segmentation of vessels, extraction of centerlines, positioning multiple analysis cut-planes (1 mm inter-plane distance) along the vessels, and computing peak velocity (PK) and flow rate (FR) for each vessel (Fig. 1b and 1c). Results: Fig. 1d and 1e present cumulative results for the control subjects, which show the PV and FR left/right ratios are close to one. this suggests hemodynamic symmetry between left and right hemispheres for controls. For the 65M patient with RMCA stenosis, the PV ratio/FR ratio in ICA and MCA were 1.37/2.26 and 1.44/7.09. The 43M patient with stenotic RMCA showed asymmetry only in the MCA-FR (1.6). The 70F case had multiple stenoses with the most pronounced asymmetry in PCA-PV and -FR (0.42 and 0.6). Discussion: We demonstrated the feasibility of using dual- venc 4D flow MRI and automated flow analysis tool to quantify hemodynamic markers such as PV, FR and flow asymmetry in ICAD patients with the potential application for ICAD risk stratification.