Growth and Late Detection of Post-Operative Cholesteatoma on Long Term Follow-Up With Diffusion Weighted Magnetic Resonance Imaging (DWI MRI): A Retrospective Analysis From a Single UK Centre.

Abstract

To evaluate the growth rate and late detection of residual cholesteatoma on long-term follow-up with diffusion weighted magnetic resonance imaging (DWI MRI) in clinically stable ears following definitive surgery, in order to define surveillance imaging protocols. Retrospective case review. Tertiary referral center. Patients who underwent DWI MRI at our institution between February 2007 and May 2013 for postoperative cholesteatoma follow-up. Non-echo planar imaging (non-EPI) Half-Fourier Acquisition Single-shot Turbo spin Echo (HASTE) DWI MRI. Intervals between the definitive surgery and the first and subsequent DWI MRI, the maximum coronal dimension of the lesion on DWI and length of follow-up. The study evaluated 152 postoperative DWI studies performed for 88 patients. In 12 cases, DWI was initially negative but became positive on repeat imaging after a mean interval of 3.8 years from the initial cholesteatoma surgery (median 3.7 years, range 1.6-7.9). Of these, 3/12 had more than one negative/indeterminate DWI before disease was eventually detected on imaging; in this subgroup, the mean interval between surgery and positive DWI was 3.2 years (median 2.6 years, range 2.3-4.2). 39 DWI positive foci with serial imaging demonstrated a mean growth rate of 4 mm/year (median 2 mm, range 0-18). After negative initial DWI, it is proposed that interval imaging should be considered for a minimum of 5 years in stable ears following definitive cholesteatoma surgery. In view of the marked variability in growth rate, an additional interval scan between 2 and 3 years postoperatively is indicated.