Volume 78, Pages 27-34 (January 2018) The Utility of Collaterals as a Biomarker in Pediatric Unilateral Intracranial Arteriopathy  Jorina Elbers, MD, MS, Derek Armstrong, MD, Susanne M. Benseler, MD, PhD, Nomazulu Dlamini, MD, PhD, Gary K. Steinberg, MD, PhD, Kristen W. Yeom, MD  Pediatric Neurology  Volume 78, Pages 27-34 (January 2018) DOI: 10.1016/j.pediatrneurol.2017.08.009 Copyright © 2017 Terms and Conditions

Figure 1 Overview of patient identification from two institutions: (1) Brain Works Registry Hospital for Sick Children cohort, and (2) Stanford University Medical Center. Of 338 children with large-vessel arteriopathy from the two centers, we identified 92 patients with unilateral intracranial arteriopathy. Of these, 44 patients fulfilled the inclusion and exclusion criteria for this study. Pediatric Neurology 2018 78, 27-34DOI: (10.1016/j.pediatrneurol.2017.08.009) Copyright © 2017 Terms and Conditions

Figure 2 MRI brain of a four-year old boy with autism spectrum disorder but no history of stroke or transient ischemic symptoms. (A) T2 FLAIR image at 3T MRI shows no focal brain lesions (e.g., gliosis or encephalomalacia) to suggest prior ischemic injury. Note, scattered areas of hyperintense T2 signal within the sulci over the right cerebral convexity that represent slow flow in the leptomeningeal collaterals. (B) Baseline digital subtraction angiography demonstrates complete occlusion of the right supraclinoid carotid artery (thin arrow), with prominent lenticulostriate collaterals. On the left, no steno-occlusive disease or collaterals are visualized. (C) Follow-up DSA 17 months later demonstrates a new 50% stenosis of the left A1 segment of the anterior cerebral artery (thin arrow) with interval development of lenticulostriate collaterals near the carotid bifurcation (thick arrow). DSA, digital subtraction angiography; FLAIR, fluid-attenuation inversion recovery; MRI, magnetic resonance imaging. Pediatric Neurology 2018 78, 27-34DOI: (10.1016/j.pediatrneurol.2017.08.009) Copyright © 2017 Terms and Conditions

Figure 3 Diffusion MRI brain of a 13-year old boy who developed acute left face, arm, and leg weakness while playing basketball, without any apparent head or neck injury. (A) Axial diffusion-weighted image obtained at 3 Tesla MRI demonstrates reduced abnormal diffusion in the right the lentiform nucleus, posterior limb of the internal capsule, insular cortex, and frontal lobe, consistent with arterial ischemic stroke. (B) MRA obtained at 3T demonstrates asymmetric, reduced flow-related enhancement and irregularity of the right supraclinoid internal carotid artery compared with the left and segmental stenosis of the right M1 middle cerebral artery (thin arrow). Right terminal internal carotid artery stenosis (thick arrow) is also evident. No collaterals are visualized. (C) Follow-up MRA with a 3T imaging unit 13 months later demonstrates discordant progression with improved flow-related enhancement through the terminal internal carotid artery flow (thick arrow), but further increased narrowing and reduced flow-related enhancement through the right M1 segment of the middle cerebral artery and the A1 segment of the anterior cerebral artery (thin arrows). No collaterals are visualized. MRA, magnetic resonance angiogram; MRI, magnetic resonance imaging. Pediatric Neurology 2018 78, 27-34DOI: (10.1016/j.pediatrneurol.2017.08.009) Copyright © 2017 Terms and Conditions