Differentiating Myelography Contrast from Intraventricular and Subarachnoid Hemorrhage Using Dual-Energy CT of the Head: A Case Report and a Review of Literature.

Single-energy computed tomography (SECT) head is a common diagnostic tool to evaluate for intracranial hemorrhage in emergency settings due to its widespread accessibility and non-invasive nature. However, SECT has densitometric evaluation limitations. For example, hyperdensities on SECT such as blood product and iodine contrast appear similarly. Dual-energy CT (DECT) is a relatively under-utilized imaging modality that has the capability to differentiate between multiple materials. This imaging technique can be extremely useful in identifying materials that are otherwise indistinguishable from standard SECT. The authors present a case of a patient with findings suspicious of intraventricular and subarachnoid hemorrhage on conventional SECT. The suspected hemorrhage was subsequently ruled out utilizing DECT, as iodinated contrast can be subtracted out, yielding an image that can differentiate iodine contrast from blood or other hyperdense material. The authors discuss the underlying physics, potential advantages, and limitations of the DECT.