Primary Brain Tumors

Preliminary Diagnosis: Primary Brain Tumors

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

MR imaging of the brain with IV contrast

II. Describe the advantages and disadvantages of this technique for diagnosing primary brain tumors.

Advantages

• Diagnostic with positive pertinent findings in the correct clinical situation.

• Able to localize the area of abnormality better than any other modality.

• Evaluates for secondary complications such as hemorrhage, mass effect, midline shift, etc.

• Does not utilize ionizing radiation.

Disadvantages

• Exposure to radiation.

• Time consuming.

• Requires significant patient cooperation to minimize motion artifact.

• MR with contrast is contraindicated in patients with renal disease (i.e. GFR < 30).

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

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

IV. What alternative imaging techniques are available?

• FDG - PET

• CT with contrast

V. Describe the advantages and disadvantages of the alternative techniques for diagnosing primary brain tumors.

FDG-PET

Advantages

• Able to distinguish benign and malignant lesions based on degree of radiopharmaceutical uptake (i.e., a low grade glioma will demonstrate significantly less uptake than a high grade glioma).

• Able to detect distant metastatic disease.

Disadvantages

• Exposes the patient to a high degree of radiation.

• Lacks the anatomic detailing of MRI and is unable to detect many secondary neurological complications.

• Unable to fully characterize properties of neoplasm to the degree that MRI can.

CT with contrast

Advantages

• Less expensive, quicker, and requires less patient cooperation than MRI.

• Can determine many secondary complications, such as hemorrhage, mass effect, midline shift, etc.

• Better than MRI at detecting calcified neoplasms.

Disadvantages

• Lacks specificity and anatomic detailing of MRI.

• Exposes patient to ionizing radiation.

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

FDG-PET

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

CT with contrast

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

• Relative contraindication in patients with renal failure.

• Relative contraindication in patients with allergy to contrast.