Abstract TP264: Comparative Performance of 7T and Conventional MRI for CAA Markers

Introduction: Cerebral amyloid angiopathy (CAA) is characterized by progressive amyloid-β deposition in cortical and leptomeningeal vessels, resulting in cognitive impairment, stroke, and intracranial hemorrhage. While definitive diagnosis requires histopathology, clinical diagnoses are primarily based on clinical and magnetic resonance imaging (MRI) findings. MRI diagnosis, often utilizing the Boston Criteria, is influenced by imaging sequences and magnet strength. 7 Tesla (7T) MRI may improve visualization of hemorrhagic markers of CAA, such as cortical microbleeds (CMBs), cortical superficial siderosis (CSS), and intragyral hemorrhage (IGH). We evaluated the sensitivity of 7T MRI to detect imaging markers of CAA in comparison to conventional MRI. Methods: We reviewed consecutive patients who underwent 7T brain MRI for evaluation of CAA at our institution between August 2022 and April 2024. Eligible patients also had a conventional (1.5-3.0 Tesla) MRI for comparison within one year. All radiographic findings were independently reviewed by two neuroradiologists (CO&MF), and any disagreements were resolved through consensus. T2* and SWI sequences were reviewed for the presence (yes/no) of CMBs, CSS, and IGH. Results are reported descriptively without statistical testing. Results: Of the 70 patients who underwent 7T MRI for evaluation of CAA, 40 had a conventional MRI for comparison. The cohort’s mean age was: 79 years; 70% female;82/5%white, and 87.5% 1.5T, 12.5% 3.0T). All 40 7T MRI scans included T2* and SWI sequences. Of the 40 conventional MRI scans, 14(35%) included SWI and 26 (65%) included T2*. On 7T T2*, the incidence of any CMBs, CSS, or IGH was 69.23%, 34.62%, 15.38% compared to 23.8%, 11.54%, 0 with conventional MRI. On 7T SWI, the incidence of any CMBs, CSS, or IGH was 57.14%,57.14%, 50% versus 50%, 50%, 7.14% with conventional MRI SWI. The “number needed to scan” to detect one additional patient with CMBs was 3,14; CSS was 5,14; and IGH was 7, 3 for 7T T2* and SWI sequences, respectively (Table 1). Conclusion: 7T MRI increased the likelihood of detecting hemorrhagic markers of CAA. The clinical implications of these findings require further study.