What is the most appropriate diagnostic imaging for a 14-year-old female with a severe, throbbing, unilateral headache and recent balance and gait problems?

From the Guidelines

The most appropriate diagnostic imaging choice for this 14-year-old girl is an MRI of the head. This patient presents with concerning symptoms including a new-onset severe, throbbing, unilateral headache and recent balance and gait problems, which raise concern for a possible intracranial lesion such as a tumor, arteriovenous malformation, or other structural abnormality.

Key Considerations

• MRI provides superior soft tissue contrast compared to CT scans and can better visualize the posterior fossa, brainstem, and cerebellum where lesions affecting balance would be located 1.
• MRI also avoids radiation exposure, which is particularly important in pediatric patients.
• While CT scans are faster and more readily available, they are less sensitive for detecting many intracranial pathologies, especially in the posterior fossa.
• The patient's symptoms have developed over time, suggesting this is not an emergency requiring immediate CT imaging.
• The absence of fever, neck stiffness, or altered mental status makes lumbar puncture less indicated as the initial diagnostic approach.

Diagnostic Approach

• Given the progressive nature of symptoms and neurological involvement, outpatient MRI represents the most appropriate next step in evaluation.
• If an abnormality is detected on noncontrast MRI scan, postcontrast imaging is usually indicated 1.
• MRI is the imaging modality of choice in patients with suspected pseudotumor cerebri, as it is more sensitive for detection of secondary signs of increased intracranial pressure 1.

Additional Considerations

• In patients with high suspicion for Chiari I deformity, a noncontrast MRI scan of the brain to include a sagittal T2-weighted sequence of the cranio-cervical junction with optional phase-contrast CSF flow study at the craniocervical junction is the study of choice 1.
• MRV is indicated in patients with possible venous sinus abnormalities, such as those with suspected pseudotumor cerebri 1.

From the Research

Diagnostic Imaging Options

The most appropriate diagnostic imaging for a 14-year-old female with a severe, throbbing, unilateral headache and recent balance and gait problems can be determined by considering the following options:

• Magnetic Resonance Imaging (MRI): This modality is sensitive for detecting abnormalities in the brain, particularly in the white and grey matter, as seen in Susac syndrome 2. MRI can also reveal cortical subarachnoid hemorrhage and extensive vasoconstriction of small- to medium-sized cerebral arteries, characteristic of Call-Fleming syndrome 3.
• Computed Tomography (CT) scan: Although less sensitive than MRI for certain conditions, CT is superior for detecting osseous lesions and lesions of the middle and external ear 4. It can also show bilateral caudate nucleus hypodensities, as seen in Wernicke's Encephalopathy 5.
• Magnetic Resonance Venography (MRV): This modality can be used to confirm cerebral venous sinus thrombosis (CVST), a less common cause of acute neurological presentation 6.

Considerations for Diagnostic Imaging

When selecting a diagnostic imaging modality, it is essential to consider the clinical presentation and potential underlying conditions. For example:

• If Susac syndrome is suspected, MRI is the preferred modality due to its sensitivity for detecting high signal intensities on T2-weighted images in the white and grey matter 2.
• If CVST is suspected, a combination of CT, MRI, and MRV may be necessary to confirm the diagnosis 6.
• If Wernicke's Encephalopathy is suspected, MRI and CT can be used to detect characteristic abnormalities, such as gadolinium enhancement of mamillary bodies and vermis, and bilateral caudate nucleus hypodensities 5.
• If Call-Fleming syndrome is suspected, MRI and angiography can be used to detect cortical subarachnoid hemorrhage and extensive vasoconstriction of small- to medium-sized cerebral arteries 3.