Case ReportArterial Spin Labeling Magnetic Resonance Imaging to Diagnose Contrast-Induced Vasospasm After Intracranial Stent Embolization
Introduction
Contrast-induced encephalopathy (CIE), also known as iodinated contrast encephalopathy, is a rare and misdiagnosed complication of intravascular injection of iodinated contrast.1, 2 Neurotoxicity from iodinated contrast agents leads to neurologic deficits, which may mimic acute stroke or transient ischemic attack. Although the underlying mechanism of injury is not well understood, it has been postulated that a combination of chemotoxic effects from contrast hyperosmolarity together with direct neurotoxicity of the contrast agent itself are responsible for arterial vasospasm, cortical edema, and neurologic effects.3, 4 Patients usually develop neurologic symptoms shortly after the exposure (2–12 hours), which vary according to the part of the brain affected (encephalopathy, convulsions, cortical blindness, and focal neurologic deficits).5, 6
Imaging is essential in confirming the diagnosis and in excluding thromboembolic and hemorrhagic complications after iodinated contrast exposure. The typical noncontrast computed tomography (CT) findings are hyperdensity of the cerebral sulci similar to subarachnoid hemorrhage and subcortical edema. On magnetic resonance imaging (MRI), hyperintense foci can be seen on fluid-attenuated inversion recovery (FLAIR) T2-weighted sequences and diffusion-weighted imaging (DWI), depending on time of onset.7, 8, 9
For the first time in literature, we report a case of acute CIE after flow-diverter stenting embolization of a recanalized intracranial aneurysm, in which only the additional use of arterial spin labeling (ASL) perfusion sequences allowed early diagnosis of distal intracranial arterial vasospasm with no signs of cortical edema in conventional CT and MRI and no vasospasm in digital subtraction angiography (DSA).
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Case Report
A 56-year-old woman with a history of hypertension and endovascular coil embolization of a 5-mm ruptured right supra-ophthalmic internal carotid artery aneurysm 6 months previously underwent a follow-up angiography, which demonstrated a recanalization of the treated aneurysm, with a 3-mm neck. The patient underwent elective flow-diverter (Pipeline 3.75−18 mm) embolization (Medtronic, Minneapolis, Minnesota, USA) of the recanalized supra-ophthalmic internal carotid artery aneurysm, with no
Discussion
Although most patients with CIE fully recover within 72 hours, a minority (approximately 15%) have persistent neurologic deficit or die of cerebral edema.2 For this reason, the condition should be early recognized to avoid potential harmful effect.
In our case, CIE was related to cerebral angiography in which a flow-diverter stent was positioned in a recanalized supra-ophthalmic aneurysm. The patient gradually developed global aphasia, right hemiparesis, left look deviation, and VII cranial
Conclusions
CIE is a rare complication of endovascular treatment for cerebrovascular diseases and always should be considered in patients with focal neurologic deficits after contrast exposure. ASL perfusion MRI with CBF maps could be a promising tool for prompt and early diagnosis of hypoperfusion due to vasospasm in CIE, when conventional CT/MRI and DSA still do not demonstrate cortical edema and distal vasospasm, respectively.
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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.