PURPOSE: Regional lung perfusion together with spirometry are established methods to aid in the prediction of postoperative (PPO) pulmonary function after lung resection. A non-invasive, non-radiation Vibration Response Imaging (VRIxp) device has been developed that analyzes lung sounds and calculates quantitative regional acoustic energy.. A multi-center study is underway to corroborate preliminary single-center results that quantitative lung sound measurements are comparable to quantitative lung perfusion for the PPO lung function (FEV1 & DLCO) and thus patient suitability for lung resection.
METHODS: Currently, 61 patients have been enrolled in the study at 6 USA sites; the first 24 consecutive patients (17 males; mean age 64±11 years) are included in this preliminary analysis. All subjects underwent pulmonary function tests, quantitative perfusion scans and VRIxp testing before resection (20 lobectomies,4 pneumonectomies). PPO values were calculated by subtracting the percent functional uptake (perfusion) or percent acoustic energy (VRI) of the lung segments to be resected from the total number of segments in that lung; calculations were compared for both methods at baseline.
RESULTS: A high correlation was found between the predictions based on VRI values and those based on perfusion (r=0.96 for ppoFEV1% and 0.90 for ppoDLCO%); overall agreement rates between the two methods were 88% and the differences were non-significant for both PPO FEV1% and DLCO% (P>0.05, Wilcoxon test. Also,there was good agreement between the two methods by the Bland-Altman plot. The limits of agreement between the two methods for ppoFEV1 were -10.2% to 12.9% with a mean difference of 1.4% (95% CI -0.96% to 3.7%) and for ppoDLCO were -11.3% to 14.9% with a mean difference of 1.8% (95% CI -0.8% to 4.4%).
CONCLUSION: Predictions based on lung function testing and quantitative breath sound measurements demonstrated high correlations with quantitive perfusion estimations and corroborate previously published results.
CLINICAL IMPLICATIONS: Given its simplicity of operation,lack of radiation and the non-invasive nature of VRIxp testing,it could be a good alternative to quantitative perfusion scans in preoperative lung resection assessment.
DISCLOSURE: Frank Detterbeck, Other Support from Deepbreeze, Ltd for standard coverage of costs for research study; No Product/Research Disclosure Information