Abstract
SUMMARY: The relevant aspects of cholesteatomas are reviewed with the emphasis on their diagnosis by using cross-sectional imaging. The indications and limitations of CT and MR imaging and the use of novel MR imaging techniques in the diagnosis of cholesteatomas are described. HRCT of the temporal bone has an excellent spatial resolution, thus even small soft-tissue lesions can be accurately delineated (high sensitivity). However, CT has poor specificity (ie, soft-tissue structures cannot be differentiated). MR imaging with the conventional sequences (T1WI, T2WI, postcontrast T1WI) provides additional information for distinguishing different pathologic entities and for accurately diagnosing primary (nonsurgical) and residual/recurrent (surgical) cholesteatomas. Higher diagnostic specificity is achieved by introducing DW-EPI, delayed postcontrast imaging, DW-non-EPI, and DWI-PROPELLER techniques. Studies using DW-non-EPI and DWI-PROPELLER sequences show promising results related to improved diagnostic sensitivity and specificity for even small (<5 mm) cholesteatomas, thus allowing avoidance of second-look surgery in the future.
Abbreviations
- DWI
- diffusion-weighted imaging
- DW-EPI
- diffusion-weighted echo-planar imaging
- DWI-PROPELLER
- diffusion-weighted imaging with periodically rotated overlapping parallel lines with enhanced reconstruction
- DW-non-EPI
- diffusion-weighted non-echo-planar imaging
- EAC
- external auditory canal
- EACC
- external auditory canal cholesteatoma
- EPI
- echo-planar imaging
- FIESTA
- fast imaging employing steady-state acquisition
- FLASH
- fast low-angle shot
- HRCT
- high-resolution CT
- NPV
- negative predictive value
- PPV
- positive predictive value
- T1WI
- T1-weighted imaging
- T2WI
- T2- weighted imaging
- TM
- tympanic membrane
- Copyright © American Society of Neuroradiology
Indicates open access to non-subscribers at www.ajnr.org