Pre-operative Evaluation of Patients with Single Pulmonary Nodule/ Lung Mass using Quantitative SPECT/CT Perfusion Lung Scan

Purpose: Lung cancer is responsible for more cancer deaths annually than any other cancer and is highly associated with chronic obstructive lung disease (COPD) secondary to smoking. Curative treatment of lung nodules or masses with malignant potential is surgical resection. However, surgery may not be an option for some patients with severe emphysema. This study investigates whether Quantitative perfusion lung scan with SPECT/ CT (QSPECT/CT) can serve as a tool to predict surgical outcomes in patients with pulmonary nodule or mass. Patients and Methods: 16 patients (9 male, 7 female), (age range 39-84yo median age 66.9yo), with pulmonary nodule or lung mass prior to surgery were included. 14 patients with emphysema had a smoking history (50.7 mean pack years) and one patient with emphysema due to alpha-1 antitrypsin deficiency. All underwent preoperative PFT (Pulmonary Function Test) and QSPECT/CT as part of their pre-operative evaluation.

Results: Nine patients underwent curative resection including segmentectomy, bullectomy, wedge resection, lobectomy, or pneumonectomy. The mean FEV1 was 2.0 L for patients prior to surgery and 0.85L for patients who did not have surgery. Following QSPECT/CT studies, lobar counts to volume ratio in each lobe was measured. The lobar count/ volume ratio prior to surgery was 0.94 (0.57-1.24) vs. 0.93 (0.48-1.67) on those who did not undergo surgery. Seven patients did not undergo surgery for the following reasons: three with benign etiology, three were poor surgical candidates and one decided to continue with CT monitoring. Patients who underwent surgical resection for the lung nodule or mass did subjectively well and maintained a higher mean FEV1 post-surgery without need for oxygen therapy. Nonsurgical patients had lower counts/ volume ratio on QSPECT/CT in the affected lobe. However, these values must be interpreted in conjunction with the patients overall pulmonary function test such as FEV1, FVC and DLCO. Conclusion: Quantitative SPECT/CT is useful in pre-surgical evaluation or radiation treatment planning of patients with pulmonary nodule or lung mass. Larger sample size of patients with underlying emphysema is needed to further evaluate the utility of this technique. We recommend Quantitative perfusion SPECT/CT for lobar assessment than traditional regional quantitative perfusion prior to surgery.