Dual-Energy CT Differentiates Contrast Staining From Hemorrhagic Conversion of Ischemic Stroke

A 67-year-old woman presented to the emergency department with fluctuating symptoms of left middle cerebral artery (MCA) distribution ischemia. The initial noncontrast computed tomography (CT) was unremarkable (Figure 1A). CT angiography (not shown) demonstrated a left distal M1 and proximal M2 thrombus, and intravenous tissue plasminogen activator (TPA) was initiated. Shortly after beginning TPA, her symptoms worsened and another noncontrast CT was obtained with dual-energy (DECT) technique (Figure 1B), which demonstrated interval development of a new small hyperdensity in the left parietal region. However, after processing of the DECT data, a “virtual noncontrast” image (Figure 1C) was generated that did not show hyperdensity in this area, indicating that it represented contrast staining rather than hemorrhage. Magnetic resonance (MR) images obtained later the same day (Figure 1D) demonstrated no evidence of hemorrhage, confirming the virtual noncontrast CT result