Imaging of otosclerosis.
ABSTRACT Imaging studies play an important role in the diagnosis of otosclerosis and in the clinical management of this disease. CT scanning at present is the tool of choice for the assessment of the labyrinthine windows and cochlear capsules. MR imaging thus far has had limited applications in the examination of the cochlear capsules but has been more useful in the assessment of the cochlear lumen prior to cochlear implant in patients with profound bilateral hearing loss.
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ABSTRACT: Otosclerosis is an otodystrophy of the otic capsule and is a cause of conductive, mixed or sensorineural hearing loss in the 2nd to 4th decades of life. Otosclerosis is categorised into two types, fenestral and retrofenestral. Imaging plays an important role in the diagnosis and management of otosclerosis. High-resolution CT (HRCT) of the temporal bone using 1-mm (or less) thick sections is the modality of choice for assessment of the labyrinthine windows and cochlear capsules. MRI has limited application in the evaluation of the labyrinthine capsules but is useful for assessment of the cochlear lumen prior to cochlear implantation in patients with profound hearing loss. The treatment of fenestral otosclerosis is primarily surgical with stapedectomy and prosthesis insertion. Patients with retrofenestral otosclerosis and profound hearing loss are treated medically using fluorides, but may derive significant benefit from cochlear implantation. This pictorial review aims to acquaint the reader with the pathology and clinical features of otosclerosis, the classical imaging appearances on CT and MRI, a radiological checklist for preoperative CT evaluation of otosclerosis, imaging mimics and a few examples of post-stapedectomy imaging and complications. Teaching points • Otosclerosis causes conductive, sensorineural and mixed hearing loss in adults.• HRCT of the temporal bone is the diagnostic imaging modality of choice.• Stapedectomy is used to treat fenestral otosclerosis.• Fluorides and cochlear implantation are used to treat retrofenestral otosclerosis.Insights into imaging. 02/2014;
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ABSTRACT: The objective of the study was to investigate the relationship between extent of otosclerotic foci and audiological findings in otosclerotic patients with mixed hearing loss using high-resolution computed tomography (HRCT) and also to measure the density of bony labyrinth in otosclerotic patients and compared with control group. This was a retrospective study. Twenty-five patients with clinical otosclerosis and mixed hearing loss were included in the study. The average threshold of air-bone conductions (AC, BC) within the 0.5-4 kHz frequency range, and average air bone gap (ABG) were calculated. Eleven patients with normal HRCT who received cochlear implant were included in the study as the control group. The lesions in HRCT were staged according to their extension. Eight different points of the otic capsule in each patient were measured using HRCT. Fifty ears total, from 25 patients, had bilateral otosclerosis. The mean AC of all the ears was 63 dB, mean BC was 35.2 dB, and mean ABG was 27.8 dB. HRCT staging indicated 22 ears had Grade 1, 21 ears had Grade 2, and 7 ears had Grade 3 lesions. There was a statistically significant difference between the mean AC, BC of ears with Grade 1 and Grade 2 when compared with the mean AC, BC of ears with Grade 3. When comparing the densitometric measurements of fissula ante fenestram localizations, a statistically significant difference was observed. HRCT examination and densitometric measurements in otosclerotic patients with mixed hearing loss presented significant results. We were unable to show a significant relationship between early stage and hearing thresholds, but there was a significant relationship in advanced stage. Densitometric measurements may provide significant results for otosclerosis, particularly for the FAF region when comparing with control group.Archives of Oto-Rhino-Laryngology 10/2013; · 1.29 Impact Factor
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ABSTRACT: Until now, the use of computed tomography (CT) in the diagnosis and evaluation of otosclerosis has been based on correlation of radiologic findings to patient histories, intraoperative examinations, and audiologic data. The purpose of this study was to compare CT findings in otosclerosis to histopathology. Prospective blinded. Radiology department in a tertiary referral hospital and otopathology laboratory. Temporal bones from patients with otosclerosis and other otologic diseases (used as controls). Blinded review of specimen CT scans by radiologists and comparison of CT findings to histopathology of the same bones. Ability of CT to diagnose otosclerosis, identify otosclerotic foci in defined zones of the otic capsule, determine endosteal layer involvement, oval window (OW) obliteration, and round window (RW) obliteration. In a randomized blinded evaluation, radiologists identified 8 of 10 bones with otosclerosis and made 3 false-positive diagnoses from the 36 control bones. Radiologic examination correctly identified otosclerosis anterior to the oval window, in the pericochlear area, and in the round window niche in 17 of 17, 9 of 11, and 3 of 6 bones, respectively. CT correctly determined involvement of the endosteal layer, OW obliteration, and RW obliteration in 5 of 8, 2 of 2, and 2 of 2 temporal bones. High-resolution CT is highly sensitive and specific for the diagnosis of otosclerosis when compared with histopathology. Very small and subtle otosclerotic foci seen on pathology may be missed on CT. Although CT was able to positively identify cochlear endosteal margin involvement, the false-negative rate on CT was significant.Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 01/2013; 34(1):22-8. · 1.44 Impact Factor