MRI-DWI detection of residual cholesteatoma: moving toward an optimum follow-up scheme.

ABSTRACT

PURPOSE: To analyse diagnostic accuracy of MRI-DWI in detecting residual disease after cholesteatoma surgery and propose an optimum follow-up (FU) scheme. METHOD: A retrospective chart review of patients who had cholesteatoma surgery in a tertiary referral centre. 3.0 T non-echo planar diffusion weighted imaging was performed as part of routine FU or indicated on the basis of clinical suspicion of disease. Imaging outcome was verified per-operatively during a second-look procedure or ossicular chain reconstruction. Diagnostic parameters were calculated and stratified by FU length. RESULTS: For the FU of 664 cholesteatoma surgeries, 1208 MRI-DWI were obtained and 235 second-look procedures were performed. Most MRI-DWI were obtained within 1.5 yrs of surgery. In this period, significantly less true positive MRI-DWI and significantly more false negative MRI-DWI for residual disease were found compared to other FU periods. Scanning after approximately 3 yrs yielded a significantly higher rate of true positive MRI-DWI, while sensitivity surpassed 80%. Younger patients had a higher risk of developing residual disease. Patients undergoing canal wall up surgery, as well as patients < 12 yrs, were at risk for false negative MRI-DWI. Obliteration reduces the risk of residual disease, while leading to less false negative MRI-DWI. CONCLUSION: A novel radiologic FU scheme for detecting residual disease is suggested for stable ears after cholesteatoma surgery standard MRI-DWI approximately 3 and 5 yrs after primary surgery, as well as MRI-DWI after approximately 9 yrs for patients with specific risk factors (i.e., patients < 12 yrs or patients undergoing canal wall up surgery without obliteration).