Preliminary Diagnosis: Central Nervous System Lymphoma

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

  • MRI of the brain with IV contrast.

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

Advantages
  • Diagnostic with positive pertinent findings in the appropriate clinical situation

  • Able to evaluate CNS anatomy exquisitely and can predict any current or impending neurologic deficits based on the location of the lesion


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  • Can assess for any secondary complications such as mass effect and midline shift

  • Does not use ionizing radation

Disadvantages
  • Expensive

  • Time-consuming imaging modality

  • Susceptible to motion artifact and requires significant patient cooperation

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

  • MRI is contraindicated in patients with non-MR-compatible hardware or foreign bodies.

  • MRI with IV contrast is contraindicated in those with decreased renal function (i.e., GFR <30).

IV. What alternative imaging techniques are available?

  • CT imaging with or without contrast

  • FDG-PET

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

CT
Advantages
  • Quick and inexpensive compared with MRI.

  • CNS lymphoma is often characteristically hyperdense on CT, raising specificity.

Disadvantages
  • Eposes the patient to ionizing radiation

  • Not as specific as MRI when diagnosing intracerebral mass

  • Has less anatomic detail compared with MRI

FDG-PET
Advantages
  • Very useful in discerning benign from agressive intracerebral masses

  • Has ability to detect distant metastatic disease

Disadvantages
  • Exposes the patient to high amounts of radiation

  • Not as specific as MRI

  • Lacks anatomic detail of MRI

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

Enhanced and nonenhanced CT

CT is contraindicated in a pregnant patient, especially within the first two trimesters.

FDG-PET

FDG-PET is contraindicated in a pregnant patient, especially within the first two trimesters.