Lung volumes before and after lung volume reduction surgery: quantitative CT analysis

Area of Science:

• Pulmonary Medicine
• Radiology
• Thoracic Surgery

Background:

• Pulmonary emphysema significantly impacts lung function and quality of life.
• Lung volume reduction surgery (LVRS) is a treatment option for severe emphysema.
• Accurate volumetric assessment of lung changes post-LVRS is crucial.

Purpose of the Study:

• To quantitatively assess the volume and severity of pulmonary emphysema using computed tomography (CT) before and after LVRS.
• To correlate CT findings with spirometric and plethysmographic data.
• To evaluate the impact of unilateral versus bilateral LVRS on lung volumes and function.

Main Methods:

• Quantitative CT scans were performed on 28 patients (median age 65) before and after LVRS (bilateral or unilateral).
• CT data (at total lung capacity and residual volume) were correlated with spirometry and body plethysmography.
• Measurements included lung volumes, total functional lung volume (TFLV), and air space to tissue space volume ratio (V(AS)/V(TS)).

Main Results:

• CT-derived lung volumes correlated well with plethysmography (p < 0.0001).
• Post-LVRS, operated lungs showed decreased lung capacity (13%) and residual volume (20%), with increased TFLV (9%) and reduced V(AS)/V(TS) at RV (23%) and TLC (14%).
• Unilateral LVRS did not affect the unoperated lung; responses were comparable between unilateral and bilateral procedures, indicating independence between lungs.

Conclusions:

• Quantitative CT is a reliable tool for assessing volumetric changes after LVRS.
• LVRS leads to significant improvements in operated lung volumes and air-tissue space ratio.
• Postoperative functional improvements correlate with changes in TFLV, suggesting expanded functioning tissue contributes to symptom palliation.