Optimal threshold in low-dose CT quantification of emphysema.

Area of Science:

• Radiology
• Pulmonology
• Medical Imaging

Background:

• Low-dose CT (LDCT) is crucial for lung cancer screening and nodule detection.
• Increasing interest exists in using LDCT for emphysema evaluation.
• A conventional threshold of -950HU is used for emphysema quantification in general populations, but an optimal threshold for LDCT is undetermined.

Purpose of the Study:

• To determine the optimal threshold for quantifying emphysema using LDCT in the Chinese population.
• To compare the efficacy of different thresholds for emphysema assessment.

Main Methods:

• 548 LDCT examinations from subjects with varying emphysema severity were analyzed.
• Emphysema extent (LAA%) was quantified across thresholds from -850HU to -1000HU.
• Correlations between LAA% and pulmonary function/classification were assessed using Pearson and Spearman coefficients.

Main Results:

• LAA% showed good correlation with pulmonary function and emphysema classification across thresholds.
• The highest correlation coefficient was observed at a threshold of -940HU, outperforming the conventional -950HU.
• This optimal threshold was consistent for both the entire lung and individual lobes.

Conclusions:

• LDCT is effective for quantitative emphysema assessment.
• A threshold of -940HU is suitable for quantifying emphysema in LDCT images for the Chinese population.
• This study refines the methodology for emphysema detection using LDCT in a specific demographic.