Magnetic resonance angiography of reversible cerebral vasoconstriction syndrome

Abstract

Objectives: To investigate the morphology, evolution, and clinical significance of vasoconstrictions seen on magnetic resonance angiography (MRA) in patients with reversible cerebral vasoconstriction syndromes (RCVS). Background: RCVS is characterized by recurrent thunderclap headaches and reversible cerebral vasoconstrictions. MRA is the study of choice for the diagnosis, evaluation and follow-up of vasoconstrictions; however, no systematic studies have been conducted to date. Methods: Patients with RCVS were consecutively recruited from August 2000 to March 2009. Diagnosed with MRA examinations, the patients were followed up until complete or near complete normalization of their vasoconstrictions. The severity of vasoconstriction of the first and second segments of major cerebral arteries (M1, M2, A1, A2, P1, P2 and basilar artery) were scored on a five-point scale: 0 (0-< 10%), 1 (10-< 25%), 2 (25-< 50%), 3 (50-< 75%) and 4 (375%). Subjects with at least one arterial segment with a vasoconstriction score 3 2 were considered eligible cases. Mean vasoconstriction scores which were derived by averaging the vasoconstriction scores of bilateral arterial segments with the same designation or different arterial segments, were used to predict ischemic complications. Results: Eighty-seven patients (M/F 8/79; average age, 48.7 (plus or minus) 10.7 years) finished the study with a mean of 3.16 MRA exams per patient. The initial number of arterial segments involved was 5.3 (plus or minus) 3.1 per patient. Segmental vasoconstrictions with a vasoconstriction score of 2 (57.9%) and length less than 5 mm (98.0%) were the most common finding. Post-stenotic dilatation was observed in 8.1% of stenotic arterial segments. Vasoconstriction was the most severe 18.1 (plus or minus) 16.3 days after headache onset (See Figure 1), roughly similar to the timing of headache resolution (18.7 (plus or minus) 10.4 days). Eight patients (9.2%) developed posterior reversible encephalopathy syndromes (PRES), located predominantly at the posterior watershed zones. Five (5.7%) patients (including 4 with PRES) had an ischemic stroke. A logistic regression forward model demonstrated that the M1-P2 mean vasoconstriction score was the best predictor for PRES (Odds ratio (OR): 8.8 (95% CI 2.3-34.3), P = 0.002), while M1 mean vasoconstriction score predicted stroke the best (OR: 3.6 (95% CI 1.3-10.4), P = 0.017). (Figure Presented). Conclusions: MRA showed different patterns of vasoconstrictions between RCVS and subarachnoid hemorrhage. It is valid in the evaluation of vasoconstrictions and predicting outcomes in patients with RCVS. Vasoconstrictions in M1 are the most important determinant of ischemic stroke, while additional involvement of P2 raised the risks for PRES.