Repeated Postoperative Follow-up Diffusion-weighted Magnetic Resonance Imaging to Detect Residual or Recurrent Cholesteatoma.

Objective: In our institution, follow-up diffusion-weighted imaging (DWI) after cholesteatoma surgery is performed at least twice. The aim of this study was to determine the yield of the second follow-up DWI (D-W MRI-2) in patients in whom the first postoperative DWI (D-W MRI-1) was negative for residual or recurrent cholesteatoma.

Study Design: A retrospective analysis.

Setting: Tertiary referral center.

Patients: Patients were included if 1) they had at least two postoperative DWI examinations after a canal wall up procedure with apparently complete cholesteatoma resection; 2) D-W MRI-1 was performed between 6 and 24 months after surgery and D-W MRI-2 performed at least 6 months after D-W MRI-1; 3) both DWI examinations were of good quality and covering the whole mastoid-middle ear region; 4) D-W MRI-1 was unequivocally negative for cholesteatoma; and 5) there was no clinical suspicion on otoscopy of recurrent cholesteatoma nor a surgical intervention between these two postoperative DWI examinations. In total, 45 separate ears in 44 patients were included.

Results: In 14 ears (31%) D-W MRI-2 was positive (n = 8) or equivocal (n = 6) for cholesteatoma. In six of eight patients with positive D-W MRI-2, follow-up surgery was performed. Cholesteatoma was found in five of them. None of the patients with equivocal findings on D-W MRI-2 was operated on. Patients with positive D-W MRI-2 were of young age. There were no observable differences for sex, side, time between surgery and D-W MRI-1, time between surgery and D-W MRI-2, or time between D-W MRI-1 and D-W MRI-2, or for the location of cholesteatoma at surgery. In the study period there was a trend to perform D-W MRI-1 and D-W MRI-2 earlier after initial surgery. In the same period, there was an evident decrease in average age of the patient population.

Conclusion: Despite cholesteatoma surgery without macroscopic residue, clinical follow-up and routine first follow-up DWI without any signs of residual or recurrent disease, repeat follow-up DWI showed evidence of cholesteatoma in 31% of patients. On the basis of the findings in this study, repeated follow-up DWI is recommended.