Quantitative Assessment of Cholesteatoma using CT Hounsfield Units: A Retrospective Observational Study

Introduction: Cholesteatoma is a degenerative middle ear pathology that, unless treated, can cause bone erosion and serious complications. High-Resolution Computed Tomography (HRCT) aids in the diagnosis by evaluating structural integrity and bone alterations. Hounsfield Unit (HU) measurements can be used to enhance diagnostic accuracy in cholesteatoma evaluation. Aim: To compare the HRCT-derived HU indexes in cholesteatomaaffected middle ear structures from healthy controls. Materials and Methods: The present retrospective observational study was conducted from May 2023 to April 2024 in the Department of Radiodiagnosis and Imaging of Justice KS Hegde Hospital, Mangalore, Karnataka, India. The study included 150 participants spanning a range of ages from 18 to 70 years. The study participants were divided into 75 healthy controls and 75 patients with surgically proven right unilateral cholesteatoma. HRCT images were used to determine HU values at five anatomical sites: the scutum, malleus, incus, fallopian canal, and lateral semicircular canal. The data were analysed using an unpaired t-test, with p-values <0.05 considered significant. Results: The mean age of the cholesteatoma group was 42.6±12.4 years, while the healthy group had a mean age of 45.3±11.8 years. There were 47 (62.7%) male patients and 28 (37.3%) female patients in the cholesteatoma group, 44 (58.7%) male patients, and 31 (41.3%) female patients in the non cholesteatoma group. Cholesteatoma-affected ears had considerably lower HU values than healthy controls in all examined areas (p<0.001). The malleus and lateral semicircular canal showed the most affecting changes. Conclusion: HRCT-based HU values demonstrate a promising aid for detecting cholesteatoma-related bone alterations. The constant and considerable reduction in HU values across distinct middle ear structures demonstrates its potential to improve diagnostic confidence and clinical decision-making.