Abstract 206: High Occurrence Rate of Parent Intracranial Artery Plaque n Patients With Acute Penetrating Artery Territory Infarcts: Interim Results of the Stroke Imaging Package Study

Background: Pathology studies suggested obstruction of the origins of penetrating arteries by parent intracranial artery plaque can cause an infarct. Using high-resolution magnetic resonance imaging(HRMRI), intracranial plaque distribution can be identified in vivo. We aimed to investigate the occurrence rate of parent intracranial artery plaque in patients with acute penetrating artery territory infarcts. Methods: Patients with first ever stroke within 72 hours from onset, confirmed by diffusion weighted imaging, were recruited from 16 medical centers. Conventional magnetic resonance imaging (MRI), magnetic resonance angiography, HRMRI (including 3-dimentional T1 images and 2-dimentional T2 images) and susceptibility-weighted imaging were performed. All patients received thorough evaluations to determine the cause of stroke according to TOAST classifications. A plaque was identified if there was eccentric wall thickening, whereas the thinnest part was estimated to be less than 50% of the thickest point by visual inspection. The plaques within middle cerebral artery(MCA) were further classified based on their orientation being centered on the superior, inferior, dorsal, or ventral side of the vessel. Possible culprit plaques were defined if superior and/or dorsal MCA plaques ipsilateral to the infarcts were observed. The plaques within basilar artery were further classified based on their orientation being centered on the ventral, dorsal, or lateral sides of the vessel ( ipsilateral to infarcts, or contralateral to infarcts). Possible culprit plaques were defined if dorsal plaques or the plaques ipsilateral to brain stem infarcts were observed. Results: Six hundred and one patients (70% male, mean age 61±16 years old, mean NIHSS 6± 5) were enrolled. Two hundred and eighty-eight(48%) patients were diagnosed with penetrating artery territory infarcts. Of them, 139 patients(48%, 85 MCAs and 54 BAs) had a plaque within the parent intracranial artery of the infarcts. Most of the parent artery plaques(119,85%) were identified as possible culprit plaques. Conclusions: High occurrence rate of parent intracranial artery plaques was observed in patients with acute penetrating artery territory infarcts.