Perfusion-weighted magnetic resonance imaging in patients with carotid artery disease before and after carotid endarterectomy

Objective: The purpose of this study was to investigate the potential of perfusion-weighted magnetic resonance imaging for preoperative and postoperative evaluation of cerebral hemodynamics in patients undergoing carotid endarterectomy for carotid artery stenosis. Methods. We examined 26 patients with angiographically proven stenoses (60%-99%) of the internal carotid artery preoperatively. Perfusion imaging studies were performed by bolus-tracking of a dosage of 0.2 mmol/kg body weight of gadolinium diethylenetriaminepentaacetic acid on a 1.5-T scanner using a T2*-weighted fast low-angle shot sequence. The observed signal intensities were converted pixel by pixel into concentration-time curves. In each patient, the hemispheres were compared and the difference between the normalized first moments (NFMs) and the percentage changes of the regional cerebral blood volume (CBV) were calculated. Three months postoperatively, perfusion-weighted magnetic resonance imaging was performed in 13 patients. Results. In patients with <80% stenosis (n = 10), there was no significant alteration of NFM and regional CBV compared with die contralateral hemisphere (-0.16 +/- 0.7 s, +5.9 +/- 24.6%). In patients with stenoses <greater than or equal to>80% (n = 16), we found an increase in NFM ipsilateral to the stenosis of 1.2 +/- 0.92 s (P <.001) and an increase of CBV of 16.8 +/- 15.2% (P <.005). Three months postoperatively, perfusion parameters were normal in all 13 patients examined. Conclusions: Perfusion-weighted magnetic resonance imaging is well suited to evaluate the preoperative and postoperative hemodynamic changes in patients with carotid artery stenosis. This noninvasive, semiquantitative magnetic resonance technique could prove to be a valuable adjunct in identification of patients who might benefit from carotid endarterectomy.