Detection of small fenestral otosclerotic lesions by high-resolution computed tomography using multiplanar reconstruction

Abstract

Objective: The aim of this study was to assess the value of multislice computed tomography (MSCT) using multiplanar reconstruction (MPR) to detect the small fenestral lesions in patients with otosclerosis.

Methods: MSCT with MPR imaging was used to evaluate 27 ears of 17 patients with otosclerosis (3 male and 14 females) ranging in age from 33 to 69 years with a mean of 49.8 year. MSCT imaging was performed using Aquilion®. Axial spiral scans with a 0.5-mm slice thickness were obtained. The acquired high-resolution data were transferred to a workstation (ALATO VIEW). MPR images were created in the planes parallel to the stapedial crus and then analyzed on the monitor screen by two radiologists (Y.T. and N.K.).

Results: MPR images showed abnormal findings in 26 of 27 ears with otosclerosis (96%), whereas axial images showed abnormal findings in only 15 of 27 ears (56%). The similar classification between both images was shown only in 9 of 27 ears (33%). In 16 ears (67%) axial images under-evaluated the lesions compared with MPR images. MPR images detected smaller foci than axial images. Air-bone gap at 0.5-4kHz tended to increase dependently on the extension of fenestral lesions evaluated by MPR images.

Conclusion: MPR images detected fenestral lesions in otosclerosis more frequently and more precisely than axial images. The extent of fenestral lesions observed on MPR images tends to be related to the degree of conductive hearing loss.