We aim to report the incidence and clinical characteristics of patients with restricted diffusion lesions in the corpus callosum following ICH. 

Restricted diffusion lesions in corpus callosum are cytotoxic lesions that have been previously described associated with various conditions including anti-epileptics use, infection, ischemia, encephalitis, metabolic disorders and trauma. Although it was not reported in patients with ICH. 

Medical records of adult patients admitted to a single tertiary center with ICH were reviewed over a 2-year period. Patients without MRI brain performed during admission were excluded. Restricted diffusion lesions are defined as increased signal intensity on MRI FLAIR, DWI sequences with decreased signal intensity in ADC. 

Among 162 patients who met inclusion criteria, 6 patients(4%, median age 53, range 37-71, 100% male, 33% white) were found to have restricted diffusion lesions in corpus callosum on MRI DWI sequence. All patients had lesions that involved splenium of the corpus callosum. The ICH locations were supratentorial in 5 patients(cortical= 3, deep= 2), and infratentorial in 1 patient. The median ICH volume was 17ml (range 1-105ml), GCS on admission was 10 (range 3-15), and modified Rankin scale at the time of discharge was 5 (range 3-6). Five (83%) patients had multi-focal lesions involving body and genu of corpus callosum, and all 5 patients also have IVH with median IVH volume of 25ml (range 2.7-55ml). Four patients were on levetiracetam and 3 patients had mild pleocytosis in CSF and were on antibiotics. None of the patients had other metabolic abnormalities during the admission. Five patients had normal cerebral angiogram and one patient had diffuse moyamoya changes bilaterally. One patient had repeat MRI after 14 days without resolution of the lesion. 

Corpus callosum lesions are rare but can be seen in patients with ICH. Larger multi-focal lesions are seen in patients with IVH extension.