Significance of lesions with decreased diffusion on MRI in patients with intracerebral hemorrhage

The study by Garg et al1 reports the frequency of de-creased diffusion using diffusion-weighted imaging and an apparent diffusion coefficient map in patients with intra-cerebral hemorrhage (ICH) undergoing MRI. Only areas of decreased diffusion that were not contiguous with the hema-toma were analyzed. A total of 36 (38%) of 95 patients with ICH had evidence of decreased diffusion on MRI scans performed at a median time interval ranging from 1.6 to 2.3 days after symptom onset. Prabhakaran et al2 similarly reported diffusion-weighted abnormalities in 23 % of the 118 patients with spontaneous ICH who underwent MRI scans within 28 days of admission. Because these patients did not have MRI scans before onset of ICH and minor neurological deterioration is not always detected, the characteristics of MRI changes are the only proof of temporal correlation with occurrence of ICH. However, the exact time interval betwee