Proptosis--Correlation and Agreement between Hertel Exophthalmometry and Computed Tomography

Area of Science:

• Ophthalmology
• Radiology
• Medical Imaging

Background:

• Proptosis measurement is crucial for diagnosing and managing orbital conditions.
• Hertel exophthalmometry and computed tomography (CT) are common methods for assessing proptosis.
• Understanding the correlation and agreement between these methods is essential for accurate clinical assessment.

Purpose of the Study:

• To evaluate the correlation and agreement between Hertel exophthalmometry and orbital CT scans in measuring proptosis.
• To determine if these two measurement techniques are interchangeable in clinical practice.

Main Methods:

• A study involving 80 patients (40 normal, 40 with proptosis) was conducted.
• Measurements were taken using the Hertel exophthalmometer and CT scans.
• Statistical analyses included unpaired t-tests, intraclass correlation coefficients (ICC), Pearson correlation coefficients (PCC), and the Bland-Altman method.

Main Results:

• Hertel exophthalmometry and CT measurements showed no significant difference (p > 0.05) but had slight variations.
• Both methods demonstrated high intra-observer reliability (ICC = 0.99).
• Strong correlations were observed (PCC = 0.96 for normal, 0.93 for proptosis), but Bland-Altman analysis revealed poor agreement, especially in proptosis cases.

Conclusions:

• While Hertel exophthalmometry and CT measurements are correlated, they exhibit poor agreement, particularly in patients with proptosis.
• The findings suggest that these measurement techniques should not be used interchangeably.
• Discrepancies between methods may lead to misinterpretation in clinical decision-making.