This patient had presented with bilateral parietal cerebral infarction 20 days prior. The axial non-enhanced CT (click image for arrows) shows bilateral frontoparietal areas of hypodensity (large arrows) involving both grey and white matter, consistent with infarcts. In addition there is a cortical ribbon of high density on the left (small green arrows).
During the second and third weeks post-infarction, isodense to hyperdense cortical bands frequently develop. These changes result from hyperaemia related to new capillary ingrowth and improved collateral circulation in thrombotic infarcts. There is also likely to be increased blood volume and decreased blood flow due to autoregulated vascular dilatation. Some of the density changes may be due to petechial haemorrhage, particularly in embolic infarcts.
Lee SH, Rao KCVG, Zimmerman RA. Cranial MRI and CT. 3rd edition. McGraw-Hill 1992.
Credit: Dr Laughlin Dawes