Severe contrast-induced encephalopathy diagnosed with postmortem dual-energy CT in an elderly patient

Abstract

Contrast-induced encephalopathy (CIE) is a rare complication associated with the use of iodine-based contrast agents and can be severe in some cases. In such cases, symptoms of encephalopathy, seizures, and neurological deficits appear shortly after contrast administration. This case report discusses a 90-year-old woman who developed severe CIE after iodine contrast agent administration. The patient underwent contrast enhanced computed tomography (CT) and left lower extremity angioplasty 2 days later. The patient's level of consciousness decreased the day after angioplasty; CT and magnetic resonance imaging (MRI) scans suggested CIE. Although the patient was treated with dialysis, but passed away 2 days after onset. Head CT at the time of onset showed extensive high-density area in the cerebral sulci. However, the distribution was different from typical subarachnoid hemorrhage due to ruptured aneurysm; subsequent MRI showed no evidence of subarachnoid hemorrhage. Therefore, CIE was suspected, rather than hemorrhage. A head dual-energy (DE)-CT, which can non-invasively assess the presence of intracranial iodine, was planned for diagnosing CIE. Although her poor condition made it difficult to performed prior to the death, so postmortem DE-CT was performed and confirmed the presence of iodine intracranially. This case suggests considering CIE in patients who develop impaired consciousness after contrast agents use, even when the contrast agents are not directly injected into cerebral blood vessels. In suspected CIE cases, DE-CT is useful for distinguishing iodine from hemorrhage.

Keywords: Case report; Contrast medium; Contrast-induced encephalopathy; Dual-energy computed tomography; Iodine.

Fig. 1

Computed tomography images of the head obtained on the day after angiography when the level of consciousness had decreased. There was extensive high-density area in the cerebral sulcus along the cerebral hemispheres. There were no high-density areas in the suprasellar cistern or sylvian fissure, which is often seen in subarachnoid hemorrhage due to aneurysmal rupture.

Fig. 2

Magnetic resonance images of the head. No abnormal signal suggesting subarachnoid hemorrhage is seen, and no aneurysm is seen on the magnetic resonance angiogram.

Fig. 3

Postmortem dual-energy computed tomography images. (A) The computed tomography image of the head reveals the persisting high-density area in the cerebral sulcus, although its density has decreased compared with the initial computed tomography image. (B) On virtual non-contrast computed tomography images generated using dual-energy computed tomography data, the high-density area in the cerebral sulcus seems faded. (C) Iodine distribution on the iodine map is consistent with the high-density zone on the plain computed tomography image. (D) The computed tomography image of the trunk shows aspiration pneumonia.