Healthy Lung Vessel Morphology Derived From Thoracic Computed Tomography

Area of Science:

• Pulmonary vascular imaging
• Medical image analysis
• Quantitative morphology

Background:

• Understanding lung vessel morphology is vital for diagnosing pulmonary diseases.
• Existing data on normal lung vasculature is limited, often based on small necropsy samples.
• Accurate morphometric data is needed to differentiate normal variations from pathological changes.

Purpose of the Study:

• To establish reference values for lung vessel morphology in a large cohort of healthy subjects.
• To develop and validate a fully-automatic algorithm for pulmonary artery and vein segmentation.
• To quantify vessel number, volume, and tortuosity in specific diameter ranges.

Main Methods:

• Computed tomography pulmonary angiography (CTPA) datasets from 123 healthy subjects were analyzed.
• A novel, fully-automatic artery/vein separation algorithm was employed.
• Vessel number, volume, and tortuosity (sum-of-angles) were quantified for vessels between 2-10 mm in diameter.
• Algorithm performance was validated against manual segmentation by a radiologist.

Main Results:

• The automated algorithm achieved a median overlap of 94.6% with manual segmentation.
• Median vessel counts per liter of lung volume were 206, with similar contributions from arteries and veins.
• Vessel density was approximately 15% higher in women than in men.
• Median arterial and venous volumes were 1.52% and 1.54% of lung volume, respectively. Tortuosity averaged 142.1 rad/m.

Conclusions:

• The fully-automatic algorithm reliably measures pulmonary vessel morphology, providing age and gender-specific data.
• Significant inter-subject variability exists in all measured parameters.
• The study provides valuable reference data for morphometric analysis of lung vasculature, aiding in the detection of pathological deviations.