The objective of this study is to estimate the timing of new diffusion weighted imaging (DWI) lesions after acute primary spontaneous intracerebral hemorrhage (sICH).
 

DWI lesions are found in nearly 50% of patients with acute sICH. However, the timing of DWI lesions after sICH ictus remains unknown. By establishing a time frame, potential pathophysiologic mechanisms for DWI lesions can be elucidated.

Between September 10, 2011 and January 15, 2017, patients were enrolled in a prospective study examining DWI lesions in acute primary sICH. Enrolled subjects received a research brain MRI after admission blinded to the clinical teams. During the same admission, select patients received a separate brain MRI as part of clinical care. Subjects with 2 scans were identified from the study cohort, and their imaging evaluated for DWI lesions. When compared to the first MRI scan, the presence of a new DWI lesion on the second MRI scan was defined as a new DWI event. A Kaplan-Meier analysis was performed to estimate the time to a new DWI event from the first MRI scan.

Among 121 enrolled subjects, 61 (56%) had two brain MRIs. Mean age was 56 years, 57.4% were male, and 50.8% were African American. The median ICH score was 1 (IQR 1). Median time from sICH onset to first MRI was 1.2 days (IQR 1.2). Median time from first MRI to a new DWI event was 4.9 days (95% CI, 3.0 to 7.8). Median time between the first and second MRI was 2.1 days (IQR 2.6).

Our data suggest that new DWI lesions occur approximately 6 days after sICH ictus. Therefore, acute interventions during the first 24 hours after sICH admission may not be associated with DWI lesions. Further research is needed to elucidate potential mechanisms associated with DWI lesions in sICH.