Fully automatic quantitative assessment of emphysema in computed tomography: comparison with pulmonary function...

Area of Science:

• Radiology
• Pulmonary Medicine
• Medical Imaging Analysis

Background:

• Accurate characterization and quantification of emphysema are crucial for effective local treatment planning and patient monitoring.
• Establishing sensitive, easily measurable, and stable imaging parameters is essential for clinical utility.
• Investigating the relationship between CT-derived parameters and established Pulmonary Function Testing (PFT) is necessary.

Purpose of the Study:

• To evaluate the utility of automatic quantification of nonenhanced thin-section CT for characterizing emphysema.
• To establish reliable CT-derived parameters and their normal ranges for differentiating emphysema, COPD, and ILD.
• To compare CT findings with PFT results in patients with COPD and ILD.

Main Methods:

• Retrospective analysis of 221 nonenhanced thin-section MDCT scans with corresponding PFT data.
• Subgroup analysis included 102 COPD stages III+IV, 44 COPD stage 0, and 33 ILD cases.
• Utilized in-house YACTA software for automatic quantification of lung volume, emphysema volume, emphysema index, mean lung density (MLD), and 15th percentile.

Main Results:

• CT-derived lung volume differed significantly across groups: smaller in ILD, larger in COPD compared to controls.
• Emphysema volume and index were significantly higher in COPD patients than in controls.
• MLD and 15th percentile showed significant differences, aiding in distinguishing COPD and ILD from controls. Normal ranges were proposed.

Conclusions:

• Automatic quantification of thin-section CT offers convincing parameters capable of differentiating emphysema, control, and ILD.
• Proposed normal ranges for emphysema index (<20%), MLD (> -850 HU), and 15th percentile (< -950 HU) may assist in individual measure assessment.
• CT-derived parameters can identify emphysema features even in individuals without formal COPD diagnosis via PFT, and vice versa.