MR imaging in the evaluation of chronic or recurrent headache.

PURPOSE To evaluate ability of magnetic resonance (MR) imaging to depict an abnormality in patients with chronic or recurrent headache without neurologic abnormality. MATERIALS AND METHODS Institutional review board approval and patient informed consent were not required. A total of 306 patients with normal neurologic findings and chronic or recurrent headache were examined with MR imaging. Patients were divided into three groups: those with no abnormality, those with minor abnormality, and those with clinically important intracranial abnormality, which may result in chronic or recurrent headache. Literature review was also performed. Upper 99.5% confidence bound for frequency of abnormal MR findings was calculated. RESULTS A total of 169 patients (55.2%) were placed in the first group, 135 (44.1%) were placed in the second group, and two (0.7%) were placed in the third group because they had a clinically important abnormality at MR imaging. Neither contrast material enhancement (n = 195) nor repeated MR imaging (n = 23) contributed to the diagnosis. Literature review revealed two previous studies concerning unspecified headache (in addition to the current study), including a total of 1036 MR imaging results and 22 (2.1%) clinically important results (upper 99.5% confidence bound, 3.4%). Twelve studies of migraine headache were found, with a total of 790 MR imaging examinations. Excluding the 19 patients with complicated migraine, the 99.5% confidence bound of the frequency of clinically important abnormality at MR imaging was estimated as 0.68%. Clinically important infarctions were noted on MR images in five (26.3%) of 19 patients with complicated migraine. CONCLUSION MR imaging is an unrewarding technique in the evaluation of patients with chronic or recurrent headache and normal neurologic findings. Neither contrast enhancement nor repeated MR imaging contributed to diagnosis, although the number of patients in the latter category was small.