Continuous arterial spin labeled perfusion magnetic resonance imaging in patients before and after carotid endarterectomy.

Continuous arterial spin labeling perfusion magnetic resonance imaging (CASL-pMRI) uses magnetically labeled arterial blood water as a tracer to obtain quantifiable measurements of cerebral blood flow (CBF) (mL/100 g-1/min-1). CASL-pMRI was used to assess CBF changes in major vascular distributions in patients (n = 10) prior to and 3 months after carotid endarterectomy (CEA). No significant change in the global baseline CBF before and after CEA was observed in the group as a whole (P = .81). In patients with reduced CBF prior to CEA (< 50 ml/100 g/min), a significant increase in global CBF following CEA was observed. An inverse relationship existed between percent change in CBF after CEA versus baseline CBF within the anterior circulation (r = -.78, P < .05) but not in the posterior distribution (r = .25, P = .63). CASL-pMRI may provide a convenient, inexpensive, noninvasive method for identifying CEA patients at risk for hyperperfusion following carotid revascularization.