Hyperintense lesions suspect for acute cerebral microbleeds on ultra-high field T1 weighted 7 Tesla MRI in patients with cerebral amyloid angiopathy

Abstract

Objective: The aims of this study are to describe T1 hyperintense lesions on 7 T MRI in patients with hereditary Dutch-type (D-CAA) and sporadic cerebral amyloid angiopathy (sCAA) and their detection rate on 7 T and 3 T MRI. Methods: We included D-CAA mutation carriers and patients with sCAA who participated between 2018 and 2023 in our natural history studies in D-CAA (AURORA) and sCAA (FOCAS). We assessed T1-weighted 7 T MRI for small (<10 mm) hyperintense lesions and T1-weighted 3 T MRI for corresponding lesions. We classified them as possible acute (1-3 days after onset) CMBs when exhibiting characteristics of CMBs on the T2*-weighted gradient echo sequence (GRE) 7 T and/or susceptibility weighted imaging (SWI) 3 T MRI. Follow-up T1-weighted 7 T and 3 T MRI and T2*-weighted GRE 7 T and/or SWI 3 T MRI were assessed to confirm the hemorrhagic origin of 7 T T1 hyperintense lesions found at baseline. Results: Baseline 7 T MRI and 3 T MRI was available in 112 participants. We found 16 T1 hyperintense lesions on 7 T in 12 participants (11 %). Of the 16 lesions, 10 (63 %) were subsequently identified on T1-weighted 3 T MRI. In patients with available follow-up imaging, 11 out of 15 lesions (73 %) were classified as acute CMBs based on 7 T and/or 3 T follow-up imaging. Conclusion: 7 T T1 hyperintense lesions were identified in approximately one in ten patients in our cohort. Acute CMBs were more often identified on 7 T MRI in comparison to 3 T MRI. This highlights the additional value of ultra-high field MRI in the assessment of CAA-related MRI markers.