Fate of diffusion restricted lesions in acute intracerebral hemorrhage

Diffusion-restricted lesions on diffusion-weighted imaging (DWI) are detected in patients with intracerebral hemorrhage (ICH). In this study, we aimed to determine the fate of DWI lesions in ICH patients and whether the presence of DWI lesions is associated with functional outcome in patients with ICH. This prospective study enrolled 153 patients with acute ICH. Baseline MRI scans were performed within 2 weeks after ICH to detect DWI lesions and imaging markers for small vessel disease (SVD). Follow-up MRI scans were performed at 3 months after ICH to assess the fate of the DWI lesions. We analyzed the associations between the characteristics of DWI lesions with clinical features and functional outcome. Seventeen of the 153 patients (11.1%) had a total of 25 DWI lesions. Factors associated with DWI lesions were high initial systolic and mean arterial blood pressure (MAP) at the emergency room, additional lowering of MAP within 24 hours, and the presence of white matter hyperintensity and cerebral microbleeds. Thirteen of the 25 DWI lesions (52%) were not visible on follow-up T2-weighted or fluid-attenuated inversion recovery images and were associated with high apparent diffusion coefficient value and a sharper decease in MAP. The regression of DWI lesions was associated with good functional outcome. More than half of the DWI lesions in the ICH patients did not transition to visible, long-term infarction. Only if the DWI lesion finally transitioned to final infarction was a poor functional outcome predicted. A DWI lesion may be regarded as an ischemic change of SVD and does not always indicate certain cerebral infarction or permanent tissue injury.