Imaging description

Acute intracerebral hematoma (ICH) accounts for 10–15% of all strokes and is associated with a higher mortality rate than both ischemic stroke and subarachnoid hemorrhage (SAH). Common causes include hypertension, amyloid angiopathy, trauma, coagulopathy, vascular anomalies including cavernomas and arteriovenous malformations (AVMs), tumors, and various drugs. Hypertension remains the single greatest modifiable risk factor for ICH.

Although clinical information is invaluable in helping to distill a reasonably short differential for acute ICH, there are many features on imaging that can be quite helpful. Amongst the features to be analyzed include location, multiplicity, symmetry, mass effect, and presence of enhancement within the hematoma. CT has a high sensitivity and the modality of choice in detecting ICH. However, MRI is very helpful to evaluate for possible underlying lesions.

Hypertensive hemorrhages most commonly occur within the basal ganglia, thalamus, and cerebellum (Fig. 9.1). However, primary brainstem and lobar bleeds can also occur in a smaller number of patients. These locations correspond to the location of microscopic changes of hyalinization, necrosis, tortuosity, and microaneurysm formation in the perforating vessels. Large lesions may extend into the ventricular system, or less commonly into the subarachnoid space. CT angiography is being increasingly utilized in the work-up of ICH. Presence of “spot sign” on CTA may be indicative of future hematoma expansion (Fig. 9.2). It is defined as spot-like and/or serpiginous foci of enhancement, within the margin of a parenchymal hematoma without obvious connection to outside vessels [1].