A crescentic rim of high-density material (acute blood) is seen over the surface of the right cerebral hemisphere (arrowheads). There is evidence of mass effect with effacement of the sulci, Sylvian fissure, and lateral ventricle (compare with left), with shift of midline structures (green to red line)

There is widespread high-density material (acute blood) within the subarachnoid space. The blood is seen in the interhemispheric fissure (1), the suprasellar cistern (2), and is layered over the tentorium cerebelli (3). The underlying cause was an aneurysm found on CT angiography

Areas of high density represent acute intracerebral haemorrhage of the right cerebral hemisphere. The high-density areas (blood) are surrounded by low-density areas (oedema). Mass effect is seen with loss of sulci on this side and slight midline shift

On the right there is a large low-density area indicating an acute infarction of the right middle cerebral artery (MCA) territory. This is causing mass effect with loss of sulci, effacement of the right lateral ventricle anterior horn (arrow) and some midline shift. For comparison an old low density infarct is seen on the left

A peripherally enhancing lesion is seen in the right cerebral hemisphere. Note its central low-density area (necrosis) and the surrounding low density (oedema). Mass effect is seen with sulcal effacement on this side and slight deviation of the falx cerebri. Biopsy proved this to be a malignant tumour