New Compartmental Reading Method for MRI Enables Accurate Localization of Cholesteatomas With High Sensitivity and Specificity.

OBJECTIVES: Cholesteatoma is an inflammatory disease, frequently observed in childrens and young adults, with a risk of relapse or recurrence. The few studies which analyzed cholesteatoma localization on magnetic resonance imaging (MRI) usually merged CT-MR images or relied on their authors' anatomical knowledge. We propose a compartmental reading method of the compartments of the middle ear cavity for an accurate localization of cholesteatomas on MR images alone. MATERIAL AND METHODS: Our method uses easily recognizable anatomical landmarks, seen on both computed tomography (CT) and MRI, to delimit the middle ear compartments (epitympanum, mesotympanum, hypotympanum, retrotympanum, protympanum, antrum-mastoid cavity). We first tested it on 50 patients on non-enhanced temporal bone CT. Then, we evaluated its performances for the localization of cholesteatomas on MRI, compared with surgery on 31 patients (validation cohort). RESULTS: The selected anatomical landmarks that delimited the middle ear compartments were applicable in 98 to 100% of the cases. In the validation cohort, we were able to accurately localize the cholesteatoma on MRI in 83% of the cases (n = 26) with high sensitivity (95.7%) and specificity (98.6%). CONCLUSION: With our compartmental reading method, based on the recognition of well-known anatomical landmarks to differentiate the compartments of the middle ear cavity on MRI, we were able to accurately localize the cholesteatoma with high (>90%) sensitivity and specificity. Such landmarks are widely applicable and only require limited learning time based on key images. Accurate localization of the cholesteatoma is useful for the choice of surgical approach.

Audiometric Results of Stapedotomy Surgery for Otoscelorsis: Influence of the Radiological Stage.

BACKGROUND: The objective of this study was to identify a correlation between the radiological stage of otosclerosis and the pre- and postoperative audiometric results of patients who underwent a stapedotomy. METHODS: Ninety-three patients with radiologically and surgically confirmed otosclerosis who underwent stapedotomy surgery and CT scanning within 18 months before the operation were included. The CT scans were interpreted by an otologist and a specialised radiologist to determine their radiological stage according to the classification of Veillon and Fraysse. The patients received a pre- and postoperative audiogram in the short and long term. RESULTS: The preoperative bone conduction thresholds were higher in patients who presented with an advanced radiological stage of otosclerosis: 32.7 dB ±â€Š12.4 compared with those who presented with a less advanced radiological stage: 24.3 dB ±â€Š10.0. The preoperative air conduction thresholds were higher in patients who presented with an impairment of the round window: 58.1 dB ±â€Š13.5 compared with those who presented with no impairment of the round window: 48.7 dB ±â€Š14.5. The postoperative improvement in the air-bone gap was significantly higher for the localised foci: 16.9 dB ±â€Š8.6 versus 11.0 dB ±â€Š9.2, but only in the short term. CONCLUSION: There was a clinical radiological correlation with the preoperative results: In BC, there was a correlation with the radiological stage of Veillon and in AC, there was a correlation with impairment of the round window. The link between the radiological stage of otosclerosis and the postoperative audiometric results is less obvious. In the short term, the audiometric improvements in the air-bone gap were greater in patients in the early stages according to the Veillon classification, but this result was not sustained in the long-term.