Report from ISMRM: Whole-body MRI and PET/CT fight to a draw
With MRI and dual-modality PET/CT both capable of whole-body imaging, it was only a matter of time before the two modalities went toe-to-toe to determine which is better at surveying the body for metastatic disease.
Dr. Gerald Antoch and colleagues at the MRI Center in Essen, Germany, arranged the match. Noting the importance to cancer staging and therapeutic decision-making, the Essen University group used both whole-body MRI and PET/CT to examine 50 patients with various types of malignant cancer. Their results were reported in a poster presentation this week at the International Society for Magnetic Resonance in Medicine meeting in Toronto.
When the bell rang, both modalities were still standing, according to Antoch. PET/CT proved superior in lymph node staging in eight patients. F-18 FDG uptake indicative of malignancy that was seen in cervical, thoracic, and abdominal lymph nodes was missed by whole-body MRI. Typically, the nodes not caught by MRI were less than 1 cm in diameter.
PET/CT was also better at finding pulmonary metastases. It detected 94 pulmonary lesions in 16 patients, compared with 58 lesions in 13 patients with whole-body MRI. For three patients, pulmonary metastases were visible only with PET/CT.
But MRI was superior for determining the presence of bone metastases, Antoch said. In seven patients, whole-body MRI uncovered bone lesions not seen on the fused PET/CT images.
Overall, MRI and PET/CT produced identical results for 33 cases. PET/CT detected metastases not shown on MRI for 12 patients, while MRI was able to delineate malignant foci not visible on PET/CT in seven cases. The modalities were equally adept at identifying metastases residing in abdominal and parenchymal organs.
The mixed findings led Antoch and his colleagues to conclude that whole-body MRI and PET/CT complement one another in staging malignant disease.
