Neuroimaging in migraine

• neuroimaging should be considered in patients with nonacute headache and an unexplained abnormal finding on the neurologic examination
  • recommendation is based on the finding that an abnormal neurologic examination increases the likelihood of intracranial pathology, such as brain tumor, arteriovenous malformation and hydrocephalus. The absence of abnormalities on neurologic examination reduces the odds of an abnormality on CT or MRI
    
    
• no recommendations are made regarding neuroimaging in the presence or absence of neurologic symptoms
  • while the data suggest that headache worsened by the Valsalva maneuver, headache that awakens the patient, new-onset headache in older patients or progressively worsening headache increases the likelihood of significant intracranial pathology, the absence of such signs and symptoms is less reliable than their presence
    
    
• neuroimaging is not usually warranted in patients with migraine and normal findings on neurologic examination
  • a lower threshold for CT or MRI may be applicable in patients with atypical features or with headaches that do not fulfill the definition of migraine. These recommendations are based on the finding that an abnormality is unlikely to be found on CT or MRI in patients with migraine and a normal neurologic examination
    
    
• imaging in tension-type headaches
  • because of insufficient evidence, a recommendation regarding neuroimaging in patients with tension-type headaches cannot be made. In two studies, no lesions were found in patients with tension-type headaches and normal neurologic examination
    
    
• use of MRI or CT
  • because of insufficient evidence, recommendations regarding the comparative sensitivity of MRI and CT cannot be made
    • the greater resolution of MRI appears to be of little clinical importance in the evaluation of nonacute headache. No comparative data exist for the effectiveness of CT scanning with and without enhancement

Notes:

• principles for diagnostic imaging
  • (1) testing should be avoided if it will not lead to a change in management;
  • (2) testing is not recommended if the patient is not significantly more likely than a person in the general population to have a significant abnormality; and
  • (3) testing that is not normally recommended may make sense in individual cases, such as in patients who are excessively worried about a serious problem as the cause of their headaches.

Reference:

• 1) Morey SS. Headache Consortium releases guidelines for use of CT or MRI in migraine work-up.Am Fam Physician. 2000 Oct 1;62(7):1699-701