Changes in interictal cerebral blood flow observed in migraine patients who respond to anti-calcitonin gene-related peptide therapy

We performed interictal arterial spin labeling (ASL) in 73 migraine patients, including those who underwent antibody switching, before and after anti-calcitonin gene-related peptide (anti-CGRP) therapy, classified cerebral blood flow (CBF) changes after treatment, compared clinical features, and identified predictors of treatment response. As a result, CBF in patients with cortical hyperperfusion (CHP) before treatment and decreased CBF after treatment (27 patients) or with no CHP before treatment and increased CBF after treatment (18 patients) became more normal. Notably, the latter group showed the highest percentage of patients with a > 50% decrease in monthly headache days (94%). Approximately 90% of patients with no CHP before treatment and decreased CBF after treatment (19 patients) showed inappropriate changes in CBF after treatment, with CBF decreasing below normal levels. Only one patient among those with no change in CBF before or after treatment regardless of pretreatment CHP (9 patients) responded to treatment. Multivariable analysis revealed CHP findings despite presentation with insomnia and insomnia with white matter hyperintensities as significant negative neuroradiological predictors of > 50% response. Interictal CBF measurements from ASL before and after anti-CGRP therapy may be clinically useful for predicting treatment efficacy.