Coregistered Ventilation and Perfusion SPECT Using Krypton-81m and Tc-99m-Labeled Macroaggregated Albumin With Multislice CT. Utility for Prediction of Postoperative Lung Function in Non-Small Cell Lung Cancer Patients

Rationale and Objective: Coregistered SPECT and CT imaging (SPECT-CT) has potential for more precise evaluation of regional pulmonary function and may be useful for prediction of postoperative lung function in non-small cell lung cancer (NSCLC) patients. The purpose of the present study was to prospectively assess the capability of coregistered SPECT-CT using krypton-81m (Kr-81m) and technetium-99m-labeled macroaggregated albumin (Tc-99m MAA) for prediction of postoperative lung function of NSCLC patients compared with SPECT and planar imaging. Materials and Methods: Sixty consecutive patients considered candidates for lung resection underwent 16-slice CT, ventilation and perfusion scintigraphy with SPECT examinations, and preoperative and postoperative measurement of FEV₁%. In each subject, SPECT and CT data were automatically fused by using commercially available software. Each postoperative FEV₁% value was predicted from uptakes of Kr-81m and Tc-99m MAA within total and resected lungs. Then, reproducibility coefficients and the limits of agreement between actual and each predicted postoperative lung function were statistically assessed. Results: Reproducibility coefficients of SPECT-CT (Kr-81m: 5.1%, Tc-99m MAA: 5.2%) were smaller than those of SPECT and planar image using Kr-81m (SPECT: 7.4%, planar image: 12.1%) and using Tc-99m MAA (SPECT: 7.2%, planar image: 11.8%). The limits of agreement for SPECT-CT (Kr-81m: 3.3 ± 10.5%, Tc-99m MAA: 5.4 ± 11.0%) were also smaller than that of SPECT and planar image and small enough for clinical purposes. Conclusions: Coregistered SPECT-CT using Kr-81m and Tc-99m MAA was able to more reproducibly and accurately predict postoperative lung function compared with SPECT and planar imaging.