Abstract WP219: Diffusion Weighted Imaging Characteristics in Deep White and Gray Matter Structures in Pediatric Patients With Moyamoya Disease

Abstract

Background: Moyamoya Disease (MMD) is a steno-occlusive arteriopathy associated with transient ischemic attacks, stroke, and cognitive impairments. In adult MMD, normal-appearing deep gray and white matter structures (NADWM) show diffusion changes that are associated with cognitive impairments. Apparent diffusion coefficient [ADC] measures the mean diffusion and is sensitive to these changes. The association of ADC changes in NADWM in pediatric MMD is not clear. Our objective is to determine whether ADC is elevated in NADWM in pediatric MMD patients. Hypothesis: ADC values in NADWM will be elevated in MMD patients compared to controls. Methods: Twenty-nine MMD patients and no stroke and 7 healthy controls (HC) were included in a single center, retrospective study. Diffusion and T1-weighted images were analyzed. We constructed a script implementing a convolutional neural network (CNN) based approach to segment and binarize cortical regions of interest (ROI) and allow extraction of ADC values (units =[x10 -6 mm 2 /s]). Segmented ROIs included: 1) all white matter (WM), and NADWM including: 2) thalamus, 3) caudate, 4) putamen, 5) globus pallidus, 6) hippocampus. Mean ADC values were compared for: 1) all ROIs between MMD and controls, and 2) all ROIs in the MMD affected and the contralateral hemispheres within the MMD group. Results: Patients were on average 7.7 + 5.4 years at MMD diagnosis. In all WM, MMD patients had significantly higher ADC values than controls in the left (mean= 865.7 + 101.6 versus 762.4 + 21.6, p=0.01) and right hemispheres (mean= 869.9 + 104.9 versus 761.0 + 21.3, p=.01), respectively. In NADGM, there were no significant differences found between the MMD and control groups in any of the NADGM ROIs. In the NADGM of MMD patients, higher ADC values were found in the putamen (mean= 778.2 + 46.0, p=0.041), hippocampus (mean=1009.5 + 58.6, p=0.005) and all NAWM (mean= 860.3 + 57.0, p<0.0001) in the MMD affected compared to the contra-lesional hemisphere. Conclusions: In pediatric patients with MMD, we found elevated ADC values in deep gray and white matter structures in the diseased hemisphere indicating alterations in the underlying microstructure. Our future analysis will integrate hemodynamic profiles and cognitive outcomes.