Pulmonary ventilation imaging based on 4-dimensional computed tomography: comparison with pulmonary function tests...

Area of Science:

• Pulmonary imaging
• Functional imaging
• Thoracic oncology

Background:

• 4-dimensional computed tomography (4D-CT) is an emerging technique for pulmonary ventilation imaging.
• Pulmonary function tests (PFTs) and single-photon emission CT (SPECT) are established clinical references for global and regional lung function, respectively.

Purpose of the Study:

• To investigate the physiological significance of 4D-CT ventilation imaging.
• To compare 4D-CT ventilation imaging with PFT measurements and SPECT ventilation images.

Main Methods:

• Prospective clinical trial involving thoracic cancer patients undergoing 4D-CT, PFT, and/or SPECT imaging.
• Regional ventilation calculated using 4D-CT (V4DCT) via deformable image registration.
• Comparison of V4DCT defect parameters with PFT measurements (FEV1, FEV1/FVC) and SPECT ventilation (VSPECT).

Main Results:

• Significant, moderate correlations found between V4DCT defect parameters and PFT measurements (e.g., V4DCT defect volume increased with decreasing FEV1/FVC, R=-0.65).
• V4DCT in VSPECT defect regions was significantly lower than in non-defect regions (P<.01).
• Moderate spatial overlap (Dice Similarity Coefficient=0.39) between V4DCT and VSPECT defects; similar ventral-to-dorsal gradients observed.

Conclusions:

• 4D-CT ventilation imaging demonstrates significant correlations with PFT and SPECT ventilation.
• These findings provide evidence for the validation of 4D-CT ventilation imaging as a functional imaging modality.