Large area of abnormal signal in the right cerebellar hemisphere, involving the inferior and medial aspects as well as the cerebellar vermis.
The abnormality is predominantly T2 hyperintense with areas of corresponding abnormal increased diffusion restriction (with some pseudo-normalisation of ADC). There are large areas of susceptibility related signal loss in keeping with haemorrhage.
Patchy enhancement within the abnormality, predominantly at the margins of the cerebellar folia. Marked mass effect results in almost complete effacement of the fourth ventricle, distortion of the medulla, and herniation of the medial portion of the right cerebellar hemisphere across the midline.
Ventricular size remains stable compared to previous CT scans. Patchy periventricular white matter T2 hyperintensity is felt to represent chronic small vessel disease, as opposed to trans ependymal fluid shift.
No intra-axial lesion elsewhere. No extra axial mass or collection.
On time-of-flight MRA, no flow-related signal is demonstrated in the right posterior inferior cerebellar artery. The left PICA is patent but does not appear to contribute significantly to the right side of the cerebellum. No intracranial occlusive disease or aneurysm was identified otherwise.
- Findings consistent with subacute PICA territory infarct, with areas of petechial haemorrhage.
- No convincing evidence of underlying mass