FDG PET/CT outperforms whole-body MRI in staging cancer patients
CHICAGO—FDG PET/CT improves staging accuracy in cancer patients compared with whole-body MRI (WBMR) at 3T field strength, according to study results presented today at the Nuclear Medicine (PET/CT Oncology) scientific session during the 94th annual meeting of the Radiological Society of North America in Chicago.

The study, presented by Ettore Squillaci, MD, compared the accuracy of PET/CT with WBMR in staging different malignant diseases and to determine the potential benefit of both modalities concerning patient management among 60 consecutive patients with known primary tumors, such as colorectal, breast, lung cancer and lymphomas.

Patients underwent F18 FDG PET/CT for tumor staging (GE Discovery ST 16) from October 2007 to September 2008. Imaging evaluation was performed for CT alone, PET plus CT viewed side by side and fused PET/CT data. WBMR examinations were performed 10 days after FDG imaging, using a 3T system (Philips Achieva) with a body coil and unlimited field of view. A coronal STIR-sequence was used for imaging of the different body regions before and after administration of 20 ml of GD-DTPA at 2ml/sec. Histopathology or clinical follow-up of 6 (+/- 2 ) month served as standards of reference.
According to the results, fused PET/CT proved significantly more accurate in assessing the overall TNM stage compared to CT alone, side-by-side CT plus PET and WBMR. The researchers found that of all 60 patients, 90 percent were correctly staged with PET/CT; 70 percent with side-by-side CT plus PET; 63 percent with CT alone and 60 percent with WBMR. No statistically significant difference could be detected between PET/CT and CT plus PET in assessing M-staging. Combined PET/CT had an impact on the treatment plan in three patients compared with WBMR.
The researchers concluded that dual-modality FDG-PET/CT was more accurate than CT alone and side-by-side CT plus PET in staging different malignant diseases. “WBMR is an effective and fast method for staging cancer patients but cannot reach accuracy of FDG-PET/CT,” the authors wrote.

Ettore said that while WBMR is an “effective and fast method for staging cancer patients, it cannot reach the accuracy of F18 FDG PET/CT.”