Overestimation of the degree of stenosis in the intracranial internal carotid artery determined by magnetic resonance angiography compared to conventional arteriography

Introduction. In the evaluation of stenoses of the extracranial internal carotid artery (ICA), there are studies that suggest that magnetic resonance angiography (MRA) can be a substitutefor conventional arteriography (CA), although it seems it has a tendency to overestimate the degree of stenosis. No similar comparison of the two techniques has been conducted in intracranial ICA. We report the case of a patient sufferin from an acute ischemic stroke and symptomatic intracranial stenosis that was overestimated when MRA was used, compared to the results obtained using CA. Case report. We report the case of a 64-year-old male with a history of arterial hypertension, hypercholesterolemia and intermittent claudication who visited the emergency department because of the sudden onset of paresthesias in the left hemiface and hand. The cranial tomography scan performed in the emergency unit ruled out any acute bleeding or early signs of a stroke. Magnetic resonance (MR) diffusion imaging showed an acute ischemic stroke in the tight parietal cortex. Extracranial MRA was normal and in the intracranial area a 73% stenosis was detected in the cavernous segment of the right ICA, whereas the use of CA showed the stenosis to be only 55%. On repeating the MRA to rule out a possible rechanneling of the ICA, the image obtained was exactly the same as the earlier one. Conclusions. Our observations suggest that, as occurs with the extracranial part, MRA tends to magnify the degree of stenosis in the intracranial vessels, and this technique would therefore appear to be less efficient than CA in the evaluation of intracranial stenoses.