Prevalence and Risk Factors Associated with Tumors and Other Structural Anomalies in Brain MRI Performed to Rule out Secondary Headache: A Multicenter Observational Study.

Headache disorders (HDs) are among the most common conditions of the central nervous system, with an estimated prevalence of 50% in adult population. The aim of this work is to analyze the prevalence of structural anomalies that may explain HDs in MRI exams performed to rule out secondary headache in real-world practice, as well as risk factors associated with these lesions. We conducted a retrospective observational study based on a consecutive case series of all patients that underwent brain MRI due to headache from 1 January 2019 to 31 May 2019. We included patients from six MRI diagnostic centers accounting for four provinces of Andalusia (southern Spain). Bivariate and multivariate logistical regression models were performed to identify risk factors associated with the outcomes (1) presence of a structural finding potentially explaining headache, (2) presence of intracranial space-occupying lesions (SOLs), and (3) presence of intracranial tumors (ITs). Of the analyzed sample (1041 patients), a structural finding that could explain headache was found in 224 (21.5%) patients. SOLs were found in 50 (6.8%) patients and ITs in 12 (1.5%) patients. The main factors associated with structural abnormalities were female sex (OR, 1.35; 95% CI, 1.02-1.85), accompanying symptoms (OR, 1.34; 95% CI, 1.05-1.89), use of gadolinium-based contrast agents (OR, 1.89; 95% CI, 1.31-2.72) and previously known conditions potentially explaining headache (OR, 2.44; 95% CI, 1.55-3.84). Female sex (