Pitfalls in the Imaging Interpretation of Intracranial Hemorrhage.

Intracranial hemorrhage (ICH) is one of the most common pathologic findings in the emergent computed tomography (CT) imaging. ICH presents as hyperattenuation in parenchymal, subarachnoid, subdural, or epidural location. However, the initial interpretation of areas of hyperattenuation can be challenging as other pathologic or nonpathologic processes (eg, calcifications, vascular malformations, highly cellular tumors, iodinated contrast, or beam-hardening artifacts) can have similar appearance. ICH can also present as isoattenuation on CT, being difficult to distinguish from the brain parenchyma. Dual-energy CT can separate hemorrhage from other causes of hyperattenuation. Albeit, this type of technology has limited availability. Pitfalls on magnetic resonance imaging (MRI) are possible but less common. The characterization of hemorrhage on conventional MR sequences, and particularly on gradient recall echo or susceptibility-weighted imaging is improved. Thus, MRI is considered a problem-solving technique. Radiologists have a prominent role in the interpretation of the initial head CT, recognizing potential pitfalls or alternative diagnosis and if necessary recommending additional work-up. Key imaging findings and technical considerations in common and uncommon pitfalls of ICH are reviewed here.