The Use of Quantitative Magnetic Resonance Perfusion for Assessment of CBF in The Perioperative Management of Carotid Stenosis: Case Illustration

Objective and Importance: Internal Carotid Artery (ICA) stenosis is a common condition with a high preva- lence in the normal population and carries a high risk of stroke. Hemodynamic impairment has been proven to be a power- ful and independent risk factor for stroke. Understanding the hemodynamics beyond a stenosis may play a role in select- ing patients who would benefit from treatment, determining the success of the treatment, and monitoring for disease recur- rence. Our group has developed a unique quantitative approach to MR perfusion. We report on the use of Quantitative Magnetic Resonance Perfusion (MRP) for assessment of Cerebral Blood Flow (CBF) pre- and post- Carotid Angioplasty and Stenting for symptomatic ICA stenosis. Clinical Presentation: A 71-year-old female with significant comorbidities presented with two episodes of left transient ischemic attacks (TIAs) over the course of one month related to high grade left ICA stenosis. Preoperative quantitative MRP showed asymmetry in CBF between the two hemispheres. Carotid angioplasty and stenting was recommended. Intervention: Left ICA angioplasty and stenting was performed and reduced the stenosis to <10%. Quantitative MRP done after the procedure revealed improved CBF to the affected side and normalization in the asymmetry of perfusion between the two hemispheres. Quantitative MRP values showed that affected regions were hypoperfused, but flow was sufficiently maintained so as to avoid infarct. Conclusion: Relative MRP images allowed us to elucidate improvement in perfusion resulting form carotid angioplasty and stenting. This novel quantitative MRP allows quantification of CBF and the potential to provide additional informa- tion on the degree of hemodynamic compromise.