Detection of occlusive lesions in intracranial arteries by three-dimensional time-of-flight magnetic resonance angiography

To evaluate the accuracy of 3-dimensional time-of-fiight magnetic resonance angiography (3D TOF MRA) for detecting intracranial arterial occlusive disease, this technique was compared with conventional angiography. The subjects were 54 patients with cerebrovascular ischemic disease. Using a semi- quantified grading scheme, stenotic lesions were assessed for each segment of the intracranial arteries to the level of the second segment. A high correlation in the degree of stenosis (Spearman rank correlation = 0.68. p = 0.0001, k statistic = 0.846) and an extremely high sensitivity (100%) for detecting occlusive lesions were found. Specificity for each segment of the intracranial arteries varied from 94.8% (Ml portion of the middle cerebral artery) to 83.3% (A1 portion of the anterior cerebral artery). However, mild stenosis tended to be slightly overestimated, and false-positive readings in specific parts of the vessels (the carotid siphon, the anterior cerebral artery orifice, and the middle cerebral artery bifurcation) were not insubstantial. We conclude that despite a relatively high false-positive rate in some regions, 3D TOF MRA is useful for evaluating intracranial major vessels in stroke patients.