Abstract WP93: Cross-Institution Adaptive CT Perfusion Protocol for Stroke Workup Can Save Time, Radiation Dose and Improve Diagnostic Quality

Abstract

Introduction: CT perfusion (CTP) is an integral part of the diagnosis and treatment pathway for acute ischemic stroke patients, however CTP protocols vary in scan duration and radiation dose across institutions. An ideal protocol would customize scan acquisition for each individual patient in real-time to avoid truncation-related postprocessing errors and minimize time and radiation dose. We explore the potential time and radiation dosage savings if such an ideal adaptive CTP protocol were implemented across institutions. Methods: We retrospectively assessed 148 CTP scans across two institutions, postprocessed by an expert reader with the CT perfusion 4D Neuro software package (GE Healthcare). Bolus arrival, peak and exit time for the arterial input (AIF) and venous output (VOF) functions were determined via inflection point analysis of time-attenuation curves. An empirically determined customized adaptive scan protocol (Figure) was generated based on each patient’s AIF/VOF curves. Resultant reduction in radiation dose, scan acquisition time and total protocol time were calculated. Results: With the adaptive protocol, all scans would have optimal diagnostic image quality, which addresses the 3% and 18% exams of sub diagnostic quality at the two institutions respectively. Average total protocol time decreased by 153 s and 12 s (59% and 9%) and average radiation dose decreased by 61% and 12% respectively, in comparison to current protocols at the two institutions. Scan acquisition time increased for 7% (11 of 148) of exams. Conclusions: An adaptive CTP protocol would realize significant time and radiation savings across institutions. Methods for real-time identification of VOF end times are currently under development.