Angioplasty for Symptomatic Middle Cerebral Artery Stenosis and a Perioperative Evaluation Using High-Resolution Magnetic Resonance Imaging at 3 T

A 46-year-old man with a history of smoking and diabetes mellitus presented with recurrent hemiparesis. Catheter angiography revealed stenosis in the right middle cerebral artery (MCA) (Figure 1). High-resolution magnetic resonance imaging (MRI) with a 3-T scanner revealed an eccentric plaque in the right MCA (Figure 2). This patient underwent angioplasty for his MCA stenosis. Surprisingly, despite prolonged dilatation with high pressures, the stenosis did not open completely after angioplasty. A follow-up high-resolution MRI scan revealed that the plaque was still there. As shown in previous reports,^{1 - 3} a high-resolution MRI scan can clearly show the wall structure of the MCA. To our knowledge, this is the first documentation of the use of high-resolution MRI before and after angioplasty of the intracranial vessel.

Current imaging modalities for the assessment of intracranial artery stenosis include magnetic resonance angiography, computed tomographic angiography, digital subtraction angiography, and transcranial Doppler ultrasonography. These evaluation tools concentrate mainly on the degree of stenosis and related hemodynamic factors, but they fail to provide information about wall structures. High-resolution MRI is currently the only noninvasive tool for the evaluation of intracranial atherosclerotic plaques. Several recent studies^{1 - 3} have confirmed the feasibility of using high-resolution MRI to depict the MCA plaque.

In our case, the MCA plaque exhibited inhomogeneous components with high and low signal intensities within itself. The plaque with focal calcification was rigid and refractory to angioplasty, even after using high-pressure balloon expansion. We presumed that the heterogeneous signal intensity of plaques may represent various plaque compositions. These plaque characteristics may be clinically meaningful, especially in the endovascular treatment of intracranial artery stenosis.