Magnetic resonance angiography in reversible cerebral vasoconstriction syndromes

Objective: To investigate the evolution and clinical significance of vasoconstriction on magnetic resonance angiography (MRA) in patients with reversible cerebral vasoconstriction syndromes (RCVS). Methods: Patients with RCVS were recruited and followed up with MRA examinations until normalization of vasoconstriction or for 6 months. The vasoconstriction severity of the major cerebral arterial segments (M1, M2, A1, A2, P1, P2, and basilar artery) was scored on a 5-point scale: 0 (0-<10%), 1 (10-<25%), 2 (25-<50%), 3 (50-<75%), and 4 (≥75%). Subjects with at least 1 segment with a vasoconstriction score ≥2 were eligible for the study. Initial mean scores of single or combined arterial segments were used to predict ischemic complications. Results: Seventy-seven patients with RCVS (8 men/69 women; average age 47.7 ± 11.6 years) finished the study with a total of 225 MRAs performed. The mean number of arterial segments involved was 5.3 ± 3.0 in the initial MRA. Vasoconstriction scores reached their maximum 16.3 ± 10.2 days after headache onset, close to the average timing of headache resolution (16.7 ± 8.6 days). Vasoconstriction evolved in a parallel trend among different arterial segments. Seven (9.1%) patients developed posterior reversible encephalopathy syndromes (PRES). Six (7.8%) patients had ischemic stroke. A logistic regression model demonstrated that the M1-P2 combined score was associated with highest risk of PRES (odds ratio [OR], 11.6, p = 0.005) and ischemic stroke (OR, 3.4; p = 0.026). Interpretation: MRA evaluation in patients with RCVS is valid. Vasoconstriction was pervasive and outlasted headache resolution. Vasoconstrictions in M1 and P2 are important determinants for PRES and ischemic stroke.