Magnetic resonance imaging of hemorrhagic conditions.

There is a stereotyped progression in the appearance of hemorrhage or thrombosis in magnetic resonance imaging performed at 1.5 tesla (T). This progression begins with low intensity on T2 weighted images (WI), and progresses to high intensity on T1 and T2 WI associated eventually, in some cases, with peripheral low intensity on T2 WI. Depending upon the etiology and location of hemorrhage or thrombosis the latter hypointensity on T2 WI may or may not be present. Hemorrhages occurring in regions of the brain not having an intact blood-brain barrier do not usually display persistence of low intensity. Regardless of etiology, consistent patterns in the evolution of hemorrhage may be observed on MR.