Reproducibility of four-dimensional computed tomography-based lung ventilation imaging.

Area of Science:

• Medical Imaging
• Radiation Oncology
• Pulmonary Function Assessment

Background:

• Four-dimensional computed tomography (4D CT) is a novel imaging technique applied in radiation oncology.
• Understanding the reproducibility of 4D CT ventilation imaging is crucial before clinical implementation.
• Assessing ventilation patterns can optimize radiation therapy for lung cancer patients.

Purpose of the Study:

• To quantify the reproducibility of 4D CT ventilation imaging.
• To assess reproducibility over different time intervals: 15 days and 5 minutes.
• To evaluate the impact of respiratory motion on ventilation imaging reproducibility.

Main Methods:

• Two sets of 4D CT ventilation images were acquired from 12 lung cancer patients.
• Reproducibility was measured using voxel-based Spearman correlation and Dice similarity coefficients (DSC).
• Linear regression analyzed the relationship between breathing depth variation and ventilation variation.

Main Results:

• Voxel-based correlation between ventilation images was moderate (average 0.50 ± 0.15).
• DSCs for segmented lung volumes (high, moderate, low function) were also moderate.
• A significant, moderate relationship was found between respiratory motion range variation and ventilation variation.

Conclusions:

• 4D CT ventilation imaging demonstrated only moderate reproducibility over 15-day and 5-minute intervals.
• Respiratory variations during 4D CT acquisition significantly reduce imaging reproducibility.
• Enhancements in 4D CT imaging techniques are required to improve the clinical utility of ventilation imaging.