Differentiating contrast staining after acute ischemic stroke from hemorrhagic transformation during emergency evaluation.

A hyperdense lesion observed in a computed tomographic (CT) image of the brain is usually suspected to be a hemorrhage during an emergency evaluation. Other rare differential diagnoses include contrast-induced encephalopathy (CIN) and acute cerebral infarction with contrast staining (CS). Recent contrast administration is a common risk factor for both CIN and CS. The former has been associated with favorable neurologic outcomes, whereas CS might have complications, such as hemorrhagic transformation (HT). Contrast staining on brain CT scans was most often reported in acute ischemic stroke patients receiving thrombolytic therapy and being administered contrast; the incidence of CS was 31% to 60% among these patients. Differentiating CS from HT after acute ischemic stroke was dependent on the presence of anatomical boundaries and on the absence of a significant mass effect and surrounding edema. The Hounsfield unit scalewas also used to differentiate contrast or hemorrhage alone from mixed contrast and hemorrhage on brain CT scans. Clarifying the properties of a hyperdense lesion on a brain CT scan is essential because the therapeutic strategies for treating CS vs HT are completely different, including differences in the therapeutic goal of controlling blood pressure and in the use of antiplatelet agents. We report a rare condition in which CS developed in an elderly patient because of end-stage renal disease, but the patient was not receiving thrombolytic therapy. An urgent brain magnetic resonance imaging scanwas used to confirmthe diagnosis of CS, which further guided the treatment of this patient.