Thymic measurements in pathologically proven normal thymus and thymic hyperplasia: intraobserver and interobserver...

Area of Science:

• Radiology and Imaging
• Thoracic Imaging
• Medical Diagnostics

Background:

• Thymic measurements on computed tomography (CT) are crucial for diagnosing thymic hyperplasia and assessing normal thymus.
• Variability in these measurements can impact diagnostic accuracy.
• Standardized measurement techniques are needed to improve reliability.

Purpose of the Study:

• To evaluate the intraobserver and interobserver variability of thymic size and CT attenuation measurements.
• To assess the impact of standardized imaging instructions on measurement reproducibility.
• To establish the reliability of CT-based thymic assessments.

Main Methods:

• Retrospective analysis of CT scans from 33 patients with thymic hyperplasia or normal thymus.
• Independent measurements of thymic size (diameters, lobe length, thickness) and CT attenuation by two radiologists.
• Statistical analysis using concordance correlation coefficients (CCCs) and Bland-Altman plots.

Main Results:

• Moderate to high intraobserver and interobserver agreement for thymic diameters and lobe length (CCCs 0.72–0.89).
• Improved agreement after providing standardized image selection instructions (CCCs 0.77–0.92).
• High reproducibility for CT attenuation measurements (CCCs 0.88–0.97), especially for thymic glands >30 HU.

Conclusions:

• Thymic size measurements on CT demonstrate moderate-to-high reliability with consistent image selection.
• CT attenuation measurements are highly reproducible, offering a reliable quantitative assessment.
• Understanding measurement variability is essential for accurate interpretation of thymic CT findings.