Abstract Number ‐ 46: Automated Magnetic Resonance Perfusion Imaging in the Management of Delayed Cerebral Ischemia: A Pilot Study

Abstract

Introduction Inadequate perfusion secondary to changes in vascular narrowing and breakdown of cerebral autoregulation is thought to be a major contributor to delayed cerebral ischemia (DCI). Subjective evaluation of narrowing of large and medium intracranial vessels on angiography detects vasospasm in up to 70% of patients, though only 30% become clinically symptomatic. There are no available tools for the quantification of tissue level perfusion to detect critical levels of ischemia in this setting. We aimed to evaluate focal perfusion changes using MR‐perfusion weighted imaging with automated thresholding of flow and timing parameters in the setting of DCI. Methods This is a prospective observational pilot study that includes seven patients with SAH. All patients underwent multimodality MRI including diffusion and perfusion imaging when there was concern for DCI. RAPID software was used to process diffusion and perfusion images and obtain threshold maps for diffusion restriction, Tmax prolongation and drops in cerebral blood volume (CBV), and cerebral blood flow (CBF). Correspondence of neuroanatomic location of focal perfusion alteration and pattern of perfusion alteration was evaluated. Results Neuroanatomical location of perfusion alteration corresponded to neurological symptoms in 86% (6/7) of patients. The prominent patterns were: prolongation of Tmax greater than four seconds (7/7), greater than 20% drop in CBF (3/7), and greater than 20% drop in CBV (3/7). Significant radiographic vasospasm on concurrently catheter angiogram and/or MR angiogram which corresponded to the supplying vessels to the neuroanatomic area with altered perfusion was seen in 71% (5/7) of the patients. Conclusions MRI‐perfusion imaging using RAPID software can help detect and quantify the presence of inadequate focal perfusion for DCI in real‐time. This tool could guide the timing and extent of endovascular vasodilatory and medical hyperdynamic treatment and larger studies of MRI‐perfusion imaging for DCI are warranted.