CT Assessment of Otic Capsule Bone Density in Paget's Disease of the Temporal Bone and Its Relationship With Hearing Loss

Abstract

Objectives: To study computed tomography findings in Paget's disease of temporal bone (PDTB) and analyze the relations between otic capsule bone mineral density values measured in Hounsfield Units (HU) and hearing loss (HL).

Study design: Observational case-control study.

Setting: Tertiary referral center.

Patients: Radiographically confirmed PDTB cases and control group.

Intervention: Diagnostic.

Main outcome measures: Hearing thresholds and computed tomography bone density values.

Results: Twenty-three ears in the case group (PDTB) and 27 control ears were included. In the PDTB group, HL was found in 87% of the ears (43% mixed) and an air-conduction threshold of 50.7 dB (SD = 19.8). In the control group, 48% of the ears showed HL (7% mixed) and an air-conduction threshold of 34.5 dB (SD = 20.6) was found; the difference was statistically significant (p < 0.05). Measurements of bone density (HU) in the otic capsule (regions of interest [ROI] 1 and 2) and in the petrous bone (ROI 3) were significantly lower (p < 0.05) in the PDTB group than in controls.The PDTB group presented a significant association between otic capsule bone density in ROI 1 and mean otic capsule density with air and bone-conduction thresholds (p < 0.05). In controls, no association was observed between any density value and audiometric thresholds.

Conclusion: PDTB patients showed more frequent HL, lower thresholds, and a higher proportion of mixed HL than controls. Bone density (HU) was decreased in all ROIs in PDTB patients in comparison with controls. Bone density in the otic capsule was associated with HL in PDTB patients, but no association was observed between bone density and HL in controls.