Neurofibromatosis

Preliminary Diagnosis: Neurofibromatosis

I. What imaging technique is first-line for this diagnosis?

• MRI imaging of the brain and spine with contrast

II. Describe the advantages and disadvantages of this technique for diagnosis of neurofibromatosis.

Advantages

• Diagnostic in the appropriate clinical setting

• Able to determine both the extent and type of intracranial anomaly associated with NF1/NF2

• Does not utilize ionizing radiation

Disadvantages

• Expensive

• Time consuming

• Requires significant patient cooperation to minimize motion artifact

• Requires the patient have adequate renal function (ie, GFR > 30 )

III. What are the contraindications for the first-line imaging technique?

• Contraindicated in patients with poor renal function (ie, GFR < 30)

• Contraindicated in patients with non–MR-compatible metallic hardware or foreign bodies

IV. What alternative imaging techniques are available?

• Contrast-enhanced CT

• Catheter-based angiography

V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of neurofibromatosis.

Contrast-enhanced CT

Advantages

• Quicker and less expensive than MR imaging

• Less prone to motion artifact

• More adept than MR at detecting associated osseous abnormalities such as sphenoid and occipital bone dysplasias, spinal scoliosis, etc

Disadvantages

• Has both a lower sensitivity and specificity in detecting associated intracranial abnormalities

• Not able to depict early parenchymal brain changes associated with neurofibromatosis and has less anatomic detail than MRI

• Exposes the patient to ionizing radiation

Catheter Angiography

Advantages

• Gold standard in detecting associated vascular lesions of NF such as aneurysms/AVMs, stenoses, etc

• Can be used as both diagnostic and therapeutic modality

Disadvantages

• Invasive procedure

• Limited to only vascular findings associated with NF

• Time consuming

• Exposes the patient to a high degree of ionizing radiation

VI. What are the contraindications for the alternative imaging techniques?

Contrast-enhanced CT

• Contraindicated in pregnant patients, especially during the first two trimesters

• Contraindicated in patients with poor renal function

Catheter Angiography

• Contraindicated in patients in a hypocoagulable state (ie, platelets < 50,000 and INR > 2)

• Contraindicated in pregnant patients

• Contraindicated in patients with poor renal function