Incidental Findings of Malignancy of the Chest by Single Photon Emission Computed Tomography Myocardial Perfusion Imaging (SPECT-CT MPI): One Year Follow-Up Report

Introduction: We recently reported six cases of pulmonary/hilar malignancies as the result of incidental findings (IF) on CT attenuation correction (CTAC) during Single Photon Emission Computed Tomography Myocardial Perfusion Imaging (SPECT-CT MPI). In this study, clinical features, diagnostic procedures, and clinical outcomes were examined on all patients who had malignancies or significant IF that required further follow-up.

Methods: Of 1,098 consecutive patients who underwent cardiac SPECT-CT MPI from September 1, 2017 to August 31, 2018, their MPI and CTAC were reviewed contemporaneously. Patients with known history of prior pulmonary or chest malignancy were excluded.

Results: A total of 79 (7.2%) patients were identified to have significant IF on CTAC. After diagnostic CT, 47 patients had significant findings that warranted further follow-up and included in this study. Eight of 1,098 patients (0.73%) and 8/79 patients (10.1%) were found to have malignancy of the chest because of IF on the CTAC. There were no statistically significant differences in baseline characteristics and cancer risk factors among patients who had cancer versus those without. At the time of diagnosis, four patients had cancer at an advanced stage, resulting in death within 12 months. Three others had early stage lung cancer and one had mantle cell lymphoma; they were alive at a mean follow-up of 17.5+/-2.1 months. Biopsy for tissue diagnosis was performed safely with needle biopsy. Major complication occurred in one patient (1/9 or 11.1%) with needle biopsy; none with surgical biopsy.

Conclusion: This study underscored the importance of reviewing CTAC images obtained during cardiac SPECT-CT MPI to detect clinically important IF.