When is brain MRI with and without contrast indicated for evaluation of headache?

WHAT NEUROIMAGING MODALITY SHOULD BE USED FOR EVALUATING HEADACHE?

The American Headache Society recommends against using computed tomography for headache when magnetic resonance imaging (MRI) is available, except in emergencies, as computed tomography takes less time.⁴ MRI is the imaging modality of choice for the workup of headaches because it has higher resolution and greater sensitivity at detecting intracranial pathologies, including posterior fossa pathology, as compared with computed tomography.

WHY WOULD I NEED TO ADD CONTRAST ENHANCEMENT?

When red-flag features are found during the evaluation of patients with headache, the differential diagnosis should be used to determine whether contrast enhancement is needed. The authors recommend ordering brain MRI with and without intravenous contrast for the evaluation of headache in patients with current or previous malignancy, immunosuppression, or focal neurologic deficits, or when the differential diagnosis includes atypical presentations of primary headache disorders, trigeminal autonomic cephalgias, intracranial infection, and intracranial hypotension or hypertension (Figure 1). This approach is illustrated in the 4 case scenarios below.

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Figure 1

Approach to determining need for contrast enhancement in the evaluation of headache.

MRI = magnetic resonance imaging; SNOOP = systemic symptoms, neurologic symptoms, onset is sudden, older patient, previous headache history/positional change/precipitators/papilledema

WHAT SHOULD I CONSIDER BEFORE ADDING CONTRAST ENHANCEMENT?

Adding contrast to imaging can have a diagnostic benefit, but this decision must take into consideration possible risks of exposure, increased chance of incidental findings, and cost.

Gadolinium-based contrast agents (GBCAs) are paramagnetic ions that enhance a brain MRI by improving the visualization of soft tissues, particularly in areas where the blood-brain barrier is disrupted. This allows for better detection of abnormalities such as tumors, infection, inflammation, active demyelination, vascular pathology, and conditions associated with low cerebrospinal fluid. The use of GBCAs is reported to be 62% more expensive than noncontrast studies and may increase the risk of incidental benign findings.² Also, GBCAs should be used cautiously in patients with acute kidney injury or severe chronic kidney disease (estimated glomerular filtration rate < 30 mL/ min/1.73 m²) and are contraindicated in pregnancy and in patients with a previous type 1 hypersensitivity reaction to GBCAs.⁵

SCENARIO 1: HEADACHE AND MALIGNANCY HISTORY

A 60-year-old woman presents to your office with new-onset generalized headaches that have occurred daily for the past 4 weeks and are associated with nausea and vomiting. She has a history of breast cancer diagnosed 3 years ago, which was treated with lumpectomy and radiation. Her neurologic examination is notable for hyperreflexia at the left patellar and Achilles tendons and a left-sided extensor plantar response.

This presentation is concerning for intracranial metastasis and warrants workup with brain MRI with and without intravenous contrast. Among the most concerning differential diagnoses in patients presenting with headache is an intracranial neoplasm. A 2025 retrospective review of 874 outpatient brain MRIs with and without intravenous contrast, indicated for evaluation of headache, found that imaging without contrast detected all intra- and extra-axial masses associated with parenchymal edema.² However, this study excluded individuals with current or previous malignancy. Therefore, when detection of intracerebral or leptomeningeal metastasis is the primary indication for neuroimaging, brain MRI with and without contrast is recommended.

In patients undergoing evaluation for secondary headache where the concern for malignancy is low and there are no other red-flag features, ordering brain MRI without contrast would be appropriate.^1,2

SCENARIO 2: MORNING HEADACHES

A 28-year-old woman presents to the office with a chief concern of new-onset generalized pressure-like headaches that are worse first thing in the morning, improve when she is upright, and are triggered by Valsalva maneuver. Her headaches are associated with bilateral pulsatile tinnitus and visual changes. On examination, she has a body mass index of 35 kg/m² and bilateral papilledema.

This presentation raises suspicion for idiopathic intracranial hypertension. One of the diagnostic criteria for idiopathic intracranial hypertension is a cerebrospinal fluid opening pressure of at least 25 cm H₂O, but before lumbar puncture is performed, neuroimaging is recommended to rule out a space-occupying intracranial lesion to avoid iatrogenic herniation and to rule out secondary causes of increased intracranial pressure.^6,7

For this scenario, the American College of Radiology recommends that either brain MRI with and without intravenous contrast or brain MRI without intravenous contrast is usually appropriate.¹ However, the authors recommend obtaining brain MRI with and without contrast as this approach provides improved venous sinus depiction, enhancement of the optic nerve head, and characterization of possible intracranial masses. The addition of magnetic resonance venography should also be considered to assess for transverse sinus stenosis, which is commonly seen in patients with idiopathic intracranial hypertension and impacts treatment options, such as venous stenting.⁶

SCENARIO 3: CLUSTER HEADACHE

A 35-year-old man presents to the office with brief episodes of severe stabbing pain in his left eye that is associated with ipsilateral conjunctival injection and lacrimation. The episodes occur around the same time each day and have happened around the same time each year for the past 4 years. His ophthalmologist noted no abnormalities, and his neurologic examination is unremarkable.

This presentation is consistent with episodic cluster headache, a type of trigeminal autonomic cephalgia. Structural lesions of the sella, posterior fossa, and pituitary gland may mimic trigeminal autonomic cephalgia symptoms, so brain MRI with and without intravenous contrast is recommended.¹

SCENARIO 4: MIGRAINE HEADACHE

A 40-year-old woman presents to the office for follow-up. For several years, twice a month, she has experienced a migraine without aura. Her migraines have not increased in frequency or severity. She has no history of malignancy or head trauma, and she is immunocompetent. A neurologic examination is unremarkable. She was recently told by a friend that she should have neuroimaging to rule out a brain tumor as the cause.

In patients with migraine without aura and no red-flag or atypical features on evaluation, the American College of Radiology, the American Headache Society, and the authors recommend against routine neuroimaging.^1,4,8,9 Despite these recommendations, it is estimated that 12.4% to 15.9% of patients with uncomplicated migraines still undergo neuroimaging.⁹ The most appropriate next steps are to focus on symptom management and provide reassurance, as the likelihood of finding a brain tumor in a patient with no malignancy history presenting with headache is less than 0.1%.³

THE BOTTOM LINE

The decision to pursue neuroimaging for a patient who presents with headache should be guided primarily by a careful history and physical examination. Attention should be given to a history of malignancy and to clinical features raising concern for secondary causes, including intracranial infection and abnormal intracranial pressure, and for differential diagnoses that include trigeminal autonomic cephalgias (Figure 1).

DISCLOSURES

The authors report no relevant financial relationships which, in the context of their contributions, could be perceived as a potential conflict of interest.