Neuroimaging utilization and findings in headache outpatients: Significance of red and yellow flags

Background Neuroimaging for headache commonly exceeds published guideline recommendations and may be overutilized. Methods We conducted a retrospective cross-sectional study of all outpatient community patients at Mayo Clinic Rochester who underwent a neuroimaging study for a headache indication in 2015. We assessed the neuroimaging utilization pattern, clinical application of red flags, and concordance with neuroimaging guidelines. Results We identified 190 outpatients who underwent 304 neuroimaging studies for headache. The median age was 46.5 years (range 18-91 years), 65% were female, and most reported no prior history of headache (n = 97, 51%). A minority of patients had prior brain imaging studies (n = 44, 23%) and neurological consultations for headache (n = 29, 15%). Few studies were ordered after consultation with a neurologist (n = 14, 7%). Seventy-seven percent of patients were documented to have a red flag justifying the imaging study. Abnormal neuroimaging findings were found in 3.1% of patients with warning flags (5/161); carotid dissection (n = 3) and reversible cerebral vasoconstrictive syndrome (n = 2). An estimated 35% of patients were imaged against guidelines. Conclusions The prevalence of serious causes of headache in a community practice was low despite the presence of a documented red flag symptom. Inadequate understanding or application of red flags may be contributing to recommendations to image patients against current guidelines. Interventions to reduce unnecessary neuroimaging of patients with headache need to be designed and implemented.