Evaluating the Diagnostic Accuracy of Tympanometry and High-Resolution Compute Tomography (HRCT) in Otosclerosis: A Retrospective Comparative Study

Abstract

Background: Otosclerosis is a progressive disease causing stapes fixation and conductive hearing loss. While tympanometry and high-resolution computed tomography (HRCT) are commonly used for diagnosis, their accuracy varies. This study evaluates the diagnostic performance of these modalities individually and in combination, using intraoperative findings as the reference standard.

Methods: A retrospective analysis of 40 patients who underwent exploratory tympanotomy for suspected otosclerosis was conducted. Preoperative tympanometry and HRCT findings were compared to intraoperative confirmation. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. McNemar’s test assessed statistical significance.

Results: Tympanometry had high sensitivity (78.13%) but low specificity (50%), whereas HRCT had lower sensitivity (43.75%) but higher specificity (62.6%). Combining both improved specificity (75%) but reduced sensitivity (37.5%). PPV remained high (85.7% for the combined test), indicating strong predictive value when both tests were positive. However, NPV was consistently low, limiting their reliability in ruling out otosclerosis. Statistical analysis showed no significant change in diagnostic accuracy when combining tests.

Conclusion: Tympanometry is useful for screening, while HRCT aids in confirmation. However, neither test alone nor in combination reliably excludes otosclerosis due to low NPV. Preoperative HRCT interpretation should involve experienced radiologists, and emerging imaging techniques may enhance diagnostic accuracy.