Incidental Findings and Normal Anatomical Variants on MRI of the Brain in Adults for Primary Headaches

Randolph W. Evans, MD


Headache. 2017;57(5):780-791. 

In This Article

Abstract and Introduction


When MRI scans of the brain are obtained for evaluation of primary headaches in adults, incidental findings are commonly present. After a review of the prevalence of incidental findings and normal anatomical variants, 21 types are presented.


About 90% of all headaches are the primary type where MRI scans of the brain will not reveal any pathology responsible for headaches. MRI scans are frequently done for primary headaches for a variety of reasons including the following: secondary pathology; at the patient's or family's request; to reassure the patient, "our stubborn quest for diagnostic certainty;"[1] faulty cognitive reasoning; the medical decision rule where it is better to impute disease than to risk overlooking it; busy practice conditions where tests are ordered as a shortcut; financial incentives; professional peer pressure where recommendations for routine and esoteric tests are expected as a demonstration of competence; and medicolegal concerns.[2] Incidental findings are common, often revealing benign pathology which may cause concern of the patient. Normal anatomical variants are also common.[3] Definitions may differ among investigators as some may classify normal anatomical variants as incidental findings while others may not.[4]