Subarachnoid hemorrhage. Concern for dissection. There is a stable right frontal ventriculostomy catheter, with its tip near the right foramen of Monro. Susceptibility remains within the dependent occipital horns as well as scattered throughout the sulci, consistent with known intraventricular and subarachnoid blood products, with interval expected evolution. There is only minimal residual sulcal FLAIR hyperintensity corresponding to blood products. There is increased conspicuity of FLAIR hyperintensity throughout the midbrain in a relatively symmetric pattern with extension into the periaqueductal gray matter. There is mild residual diffusion restriction noted. There is also now involvement of the ventral and dorsal pons.There is a linear focus of mild diffusion restriction the lateral right cerebellum without significant FLAIR abnormality at this time. There are few scattered punctate foci of nonspecific T2/FLAIR hyperintensity in the cerebral white matter bilaterally, not well delineated on prior exam secondary to motion artifact. There is extra-axial FLAIR hyperintensity along the frontal lobes bilaterally, slightly more prominent on the left, extending into the anterior interhemispheric fissure along the falx. There is a thin collection of increased T1 signal or enhancement along the left anterior cranial fossa floor, with similar findings identified along the left tentorium and posterior fossa. Retrospectively, these findings are likely present on the prior exam.There is no intracranial mass or mass effect. No parenchymal or leptomeningeal enhancement. Right parietal scalp edema is noted. There is trace right mastoid fluid.
1. Interval acute right cerebellar lacunar infarct.2. Limited evaluation secondary to lack of precontrast T1-weighted images. Persistent now subacute trace right greater than left frontal as well as left tentorial and posterior fossa subdural hematomas/collections with possible reactive dural thickening/enhancement, without gross interval change.3. Probable interval evolution of previous abnormality in the midbrain with now findings involving the ventral and dorsal pons, likely representing edema and ischemic injury. Osmotic demyelination also remains a possibility although distribution is not characteristic.4. Interval expected evolution of diffuse subarachnoid and intraventricular blood products. Stable right transfrontal ventriculostomy catheter in place without evidence of hydrocephalus.