Characterizing Spatial Lung Function for Esophageal Cancer Patients Undergoing Radiation Therapy

Area of Science:

• Medical Imaging
• Pulmonary Medicine
• Oncology

Background:

• Esophageal cancer treatment, including chemoradiation and surgery, can lead to pulmonary complications.
• Four-dimensional computed tomography-ventilation (4DCT-ventilation) is an emerging imaging technique for assessing lung ventilation using 4DCT data.
• Previous studies have focused on 4DCT-ventilation in lung cancer, but its application in esophageal cancer patients is underexplored.

Purpose of the Study:

• To characterize the spatial lung function of patients with esophageal cancer using 4DCT-ventilation.
• To establish baseline ventilation parameters for this patient population.
• To explore the relationship between ventilation patterns and thoracic comorbidities or radiologist-identified defects.

Main Methods:

• Thirty-five esophageal cancer patients undergoing 4DCT scans were analyzed.
• 4DCT-ventilation maps were generated using a density change-based algorithm.
• Radiologist interpretations and quantitative metrics (e.g., coefficient of variation, Vent-SI) assessed ventilation profiles and heterogeneity.

Main Results:

• Radiologist review identified lobar defects in 26% and gravity-dependent atelectasis in 46% of patients.
• Baseline quantitative metrics included coefficient of variation (0.52 ± 0.20) and Vent-SI (72.5 ± 14.6).
• Vent-SI values differed significantly between patients with and without thoracic comorbidities (P=0.05), and anteroposterior ventilation distinguished patients with gravity-dependent atelectasis (P<0.01).

Conclusions:

• Approximately 30% of esophageal cancer patients exhibit significant ventilation heterogeneity.
• 4DCT-ventilation provides a method to characterize lung function in esophageal cancer patients.
• This characterization using quantitative metrics and radiologist observations can inform future applications of 4DCT-ventilation to mitigate thoracic toxicity.