Prospective comparison of F-FDG PET/MRI and F-FDG PET/CT for thoracic staging of non-small cell lung cancer.

Objectives: To compare the diagnostic performance of F-FDG PET/MRI and F-FDG PET/CT for primary and locoregional lymph node staging in non-small cell lung cancer (NSCLC).

Methods: In this prospective study, a total of 84 patients (51 men, 33 women, mean age 62.5 ± 9.1 years) with histopathologically confirmed NSCLC underwent F-FDG PET/CT followed by F-FDG PET/MRI in a single injection protocol. Two readers independently assessed T and N staging in separate sessions according to the seventh edition of the American Joint Committee on Cancer staging manual for F-FDG PET/CT and F-FDG PET/MRI, respectively. Histopathology as a reference standard was available for N staging in all 84 patients and for T staging in 39 patients. Differences in staging accuracy were assessed by McNemars chi test. The maximum standardized uptake value (SUV) and longitudinal diameters of primary tumors were correlated using Pearson's coefficients.

Results: T stage was categorized concordantly in F-FDG PET/MRI and F-FDG PET/CT in 38 of 39 (97.4%) patients. Herein, F-FDG PET/CT and F-FDG PET/MRI correctly determined the T stage in 92.3 and 89.7% of patients, respectively. N stage was categorized concordantly in 83 of 84 patients (98.8%). F-FDG PET/CT correctly determined the N stage in 78 of 84 patients (92.9%), while F-FDG PET/MRI correctly determined the N stage in 77 of 84 patients (91.7%). Differences between F-FDG PET/CT and F-FDG PET/MRI in T and N staging accuracy were not statistically significant (p > 0.5, each). Tumor size and SUV measurements derived from both imaging modalities exhibited excellent correlation (r = 0.963 and r = 0.901, respectively).

Conclusion: F-FDG PET/MRI and F-FDG PET/CT show an equivalently high diagnostic performance for T and N staging in patients suffering from NSCLC.