Comparison between quantitative computed tomography, scintigraphy, and anatomical methods for prediction of postoperative FEV1 and DLCO: effects of chronic obstructive pulmonary disease status and resected lobes

Abstract

Background: Postoperative assessment of pulmonary function is important for estimating the risk of thoracic surgery and long-term disability following pulmonary resection, including predicted postoperative (ppo) forced expiratory volume (FEV) in one second (ppoFEV 1 ) and percent predicted lung diffusion capacity for carbon monoxide (ppo%DLCO) estimation. The ppo values were compared using four different estimation methods between chronic obstructive pulmonary disease (COPD) and non-COPD patients and according to the resected lobe. Methods: This prospective study included 59 eligible patients requiring single lobectomy and succeeded in performing pulmonary function tests at 3 and 12 months after lobectomy. The ppoFEV 1 and ppo%DLCO were compared with poFEV 1 and po%DLCO obtained at 3 and 12 months after lobectomy. The ppo values were estimated using the four usual methods: the 19-segment anatomical technique (S), perfusion scintigraphy (Q), quantitative CT (CT), and quantitative CT with low attenuation volume (CT LAV ) subtraction. Results: For non-COPD and COPD patients, the smallest mean difference between ppo and po values was observed by S for FEV 1 and %DLCO. Based on the resected lobe, the smallest mean difference was observed by (I) Q for right upper lobectomy (RUL) excluding %DLCO at 12 months by S, (II) S for left upper lobectomy (LUL), (III) CT and CT LAV for right lower lobectomy (RLL), and (IV) CT and CT LAV for left lower lobectomy (LLL) at 12 months. The ppo values calculated by S for RUL (FEV 1 at 3 and 12 months and %DLCO at 3 months) and by all four methods for LLL (FEV 1 and %DLCO at 3 months) were smaller than the po values. Conclusions: The S method is adequate for calculating ppoFEV 1 and ppo%DLCO when patients are classified as non-COPD and COPD. However, S sometimes overestimates the ppoFEV 1 and ppo%DLCO when patients are classified according to the resected lobe. The CT LAV method may be the method of choice instead of S for calculating ppoFEV 1 and ppo%DLCO in patients who undergo lung lobectomy despite the presence or absence of airflow limitation.

Software-Based Assessment of Well-Aerated Lung at CT for Quantification of Predicted Pulmonary Function in Resected NSCLC

“…Similar results was demonstrated by Sverzellati et al, who reported a significant correlation between estimated FEV1 and measured FEV1 values (r = 0.97) three months after surgery [ 9 ]. According with our findings, Yokoba et al identified a significant correlation between postoperative FEV1 and %DLCO and corresponding predicted values obtained by QCT; nevertheless, our results showed a higher tendency to underestimate PFTs, likely for the narrower range of CT density considered as WAL in our study (between −950 and −750 HU vs. −950 and −600 HU) [ 8 ].…”

“…Emerging techniques, such as CT ventilation imaging, strongly correlate with PET ventilation in evaluating relative lobar function; nevertheless, it requires images acquired at end-expiration and end-inhalation, increasing radiation exposure [ 7 ]. QCT has the potential to predict post-surgical lung function by quantifying the ventilated area of the lobe that might be resected [ 8 , 9 ]. Several types of software can calculate, on the basis of CT Hounsfield units (HU) thresholds, the well-aerated lung (WAL) as a surrogate of normal lung [ 10 ].…”

Pulmonary function changes after thoracoscopic lobectomy versus intentional thoracoscopic segmentectomy for early-stage non-small cell lung cancer

“…Patients who had poor lung function were excluded during the study design. Therefore, quantitative ventilation-perfusion scans would be not essential in this study (32)(33)(34), and the results could not be extrapolated to patients with poor lung function. Then segmental planes were divided by staplers in our patients.…”

A Modified Calculation Improves the Accuracy of Predicted Postoperative Lung Function Values in Lung Cancer Patients

“…Brunelli et al reported similar results regarding extended lung resection, suggesting that measurements of ppoFEV1 for pneumectomies need to be reconsidered [ 13 , 14 , 22 ]. Brunelli et al showed similar results for extended lung resection, even stating, that measurements of ppoFEV1 for risk stratification for pneumectomies need to be reconsidered [ 9 , 13 ]. Therefore, we excluded pneumectomy patients for our customized FEV1 (Fig.…”

“…Yokoba et al found that COPD is an independent factor for an inaccurate ppoFEV1. The authors suggest separating the calculation of patients with and without COPD [ 13 ].…”