Imaging

Meningitis

Preliminary Diagnosis: Meningitis

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

  • MR imaging of the brain and spine with and without contrast

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

Advantages

  • May be diagnostic in certain clinical settings

  • Able to locate the focal area of meningeal inflammation and predict any neurologic abnormalities

  • Able to evaluate for any secondary complications from a primary infectious or inflammatory meningitis, such as an intraaxial or extraaxial abscesses, empyema, encephalitis, ventriculitis, hydrocephalus, and/or petechial hemorrhages

  • Does not make use of any ionizing radiation

Disadvantages

  • Expensive

  • Time-consuming

  • Requires marked patient cooperation to limit motion artifact

  • MR imaging with intravenous contrast requires that patient have good renal function with GFR >60; administration of intravenous contrast decided on a case by case basis with GFR >30 and <60

  • Meningitis is a clinical/laboratory diagnosis that may occur in the setting of normal imaging

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

  • Contraindicated in patients with non-MR compatible hardware and foreign bodies

  • Intravenous contrast requires that patient have good renal function with GFR >60. Administration of intravenous contrast is decided on a case by case basis with GFR >30 and <60.

IV. What alternative imaging techniques are available?

  • Nonenhanced and enhanced CT imaging of the brain

  • CT spinal myelography

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

Nonenhanced and enhanced CT imaging of the brain

Advantages

  • Able to detect primary forms of infection causing a secondary meningitis, such as paranasal sinus and/or temporal bone infection

  • May be performed much quicker than MR imaging, requires less patient cooperation, and is associated with less motion artifact compared to MR imaging

Disadvantages

  • Less specific and less adept in detailing secondary complications from a primary meningitis.

  • Exposes the patient to ionizing radiation

  • Has less soft tissue detail compared to MR imaging

CT spinal myelography

Advantages

  • Demonstrates thickening of the nerve roots, blockage of CSF flow, and irregular contour of the cauda equina/thecal sac to demonstrate/diagnose spinal meningitis

Disadvantages

  • Invasive procedure that exposes a patient to all the risks of an invasive procedure

  • Exposes a patient to ionizing radiation

  • May not be helpful in diagnosing intracranial compared to spinal meningitis

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

Nonenhanced and enhanced CT imaging of the brain

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

CT spinal myelography

  • Contraindicated in hypocoagulable patients: INR greater than 2.0 and platelets less than 50,000

You must be a registered member of Endocrinology Advisor to post a comment.

Sign Up for Free e-Newsletters

CME Focus