Necrotizing (malignant) external otitis: prospective comparison of CT and MR imaging in diagnosis and follow-up

Radiology. 1995 Aug;196(2):499-504. doi: 10.1148/radiology.196.2.7617867.


Purpose: To compare computed tomography (CT) and magnetic resonance (MR) imaging in the diagnosis and follow-up of necrotizing external otitis.

Materials and methods: CT and MR imaging were performed in seven patients at diagnosis and at 6 and 12 months after initiation of therapy. Imaging findings were compared and correlated with the clinical course of the disease.

Results: Cortical bone erosion was best seen on CT scans (n = 5 vs n = 0 on MR images) and failed to normalize with cure. Subtemporal soft-tissue abnormalities (n = 7 with both modalities) were better appreciated with MR imaging and had low signal intensity on T1- and T2-weighted images. Soft-tissue changes improved but did not disappear completely with treatment.

Conclusion: CT is preferred at initial diagnosis, as small cortical erosions are better seen. Either modality can be used to follow up soft-tissue evolution. MR imaging may be better for evaluation and follow-up of meningeal enhancement and changes within the osseous medullary cavity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Ear Canal / pathology
  • Ear, External / pathology
  • Follow-Up Studies
  • Humans
  • Magnetic Resonance Imaging
  • Necrosis
  • Otitis Externa / diagnosis*
  • Otitis Externa / diagnostic imaging
  • Otitis Externa / microbiology
  • Prospective Studies
  • Pseudomonas Infections / diagnosis*
  • Pseudomonas Infections / diagnostic imaging
  • Time Factors
  • Tomography, X-Ray Computed