A dense subdural collection is demonstrated overlying the right cerebral convexity measuring up to 1 cm in maximal depth. There is also subdural blood seen tracking along the right tentorium as well as along the falx. No evidence of acute intraparenchymal haemorrhage. There is mild underlying mass effect characterized by sulcal effacement but no significant midline shift. No herniation.
No CT evidence of acute infarction. The ventricles and basal cisterns are preserved. Appearances within the posterior fossa are suspicious for mega cisterna magna or alternatively an arachnoid cyst.