Head-to-Head Prospective Comparison of Quantitative Lung Scintigraphy and Segment Counting in Predicting Pulmonary...

Prediction of postoperative pulmonary function in lung cancer patients before tumor resection is essential for patient selection for surgery and is conventionally done with a nonimaging segment counting method (SC) or 2-dimensional planar lung perfusion scintigraphy (PS). The purpose of this study was to compare quantitative analysis of PS to SPECT/CT and to estimate the accuracy of SC, PS, and SPECT/CT in predicting postoperative pulmonary function in patients undergoing lobectomy. Methods: Seventy-five non-small cell lung cancer patients planned for lobectomy were prospectively enrolled (68% male; average age, 68.1 ± 8 y). All patients completed tests of preoperative forced expiratory volume capacity in 1 s (FEV1) and diffusing capacity of the lungs for carbon monoxide (DLCO), as well as ^99mTc-macroaggregated albumin PS and SPECT/CT quantification. A subgroup of 60 patients underwent video-assisted thoracoscopic lobectomy and measurement of postoperative FEV1 and DLCO. Relative uptake of the lung lobes estimated by PS and SPECT/CT was compared. Predicted postoperative FEV1 and DLCO were derived from SC, PS, and SPECT/CT. Prediction results were compared between the different methods and the true postoperative measurements in patients who underwent lobectomy. Results: Relative uptake measurements differed significantly between PS and SPECT/CT in right lung lobes, with a mean difference of -8.2 ± 3.8, 18.0 ± 5.0, and -11.5 ± 6.1 for right upper, middle, and lower lobes, respectively (P < 0.001). The differences between the methods in the left lung lobes were minor, with a mean difference of -0.4 ± 4.4 (P > 0.05) and -2.0 ± 4.0 (P < 0.001) for left upper and lower lobes, respectively. No significant difference and a strong correlation (R = 0.6-0.76, P < 0.001) were found between predicted postoperative lung function values according to SC, PS, SPECT/CT, and the actual postoperative FEV1 and DLCO. Conclusion: Although lobar quantification parameters differed significantly between PS and SPECT/CT, no significant differences were found between the predicted postoperative lung function results derived from these methods and the actual postoperative results. The additional time and effort of SPECT/CT quantification may not have an added value in patient selection for surgery. SPECT/CT may be advantageous in patients planned for right lobectomy, but further research is warranted.