Value of dual energy CT in post resuscitation coma. Differentiating contrast retention and ischemic brain parenchyma

Abstract

Applications of dual-energy computed tomography and virtual non-contrast technique in neuroimaging are still emerging. While the role of DECT in differentiating parenchymal hemorrhage and contrast media after mechanical revascularization is well recognized, the value of DECT in evaluation of brain ischemia in post resuscitation patients who have received intravenous (IV) iodinated contrast is not well documented. We present a challenging case where DECT helped explain hyperattenuation in cortical grey matter and deep grey nuclei as well as cerebellar hemispheres in a comatose patient post cardiac arrest following massive pulmonary embolism.

Keywords: Brain ischemia; Contrast retention; Dual-energy computed tomography (DECT); Virtual non-contrast (VNC).

Fig. 1

Axial non-contrast CT head images demonstrating areas of subarachnoid hyperdensities termed as pseudosubarachnoid appearance due to vascular engorgement secondary to diffuse cerebral edema and underlying history of rescusitation from cardiopulmonary arrest.

Fig. 2

Left column: Non-contrast CT head demonstrates pronounced sulcal hyperdensity as well as hyperdense left thalamus, cortical and sub-cortical areas and cerebellum. Mean attenuation value was 103.17 HU in the right parasagittal parietal cortex and subcortical region, 109.25 Hounsfield unit (HU) in the left thalamus, and 112.27 HU in the right cerebellar hemisphere. Middle and right columns (Dual-Energy CT images): The right sided fused images of the brain demonstrate bright areas of contrast retention within the subarachnoid spaces as well as within patchy cortical and sub-cortical areas, left thalamus, and cerebellum. The middle subtracted virtual non-contrast (VNC) images demonstrate extensive low attenuation in areas of contrast retention consistent with widespread areas of infarction in a pattern consistent with diffuse hypoxic-ischemic injury.