Molecular Imaging News
May 17, 2005
Whole-body MRI Superior to Bone Scintigraphy in Detecting Cancer Metastasis; PET Superior to MRI in Soft Tissues
American Roentgen Ray Society
Whole-body MRI with an automatic moving table is effective for evaluating the entire skeleton in patients with suspected bone metastasis in a single imaging scan—and it only takes between 15 and 18 minutes, say two different European studies.
For one study, researchers from the Clinica Girona in Catalonia, Spain, performed whole-body MRI on 42 patients with known malignant tumors and a suspicion of bone lesions. Upon analyzing the results, the researchers found that whole-body MRI had a sensitivity of 100%, a specificity of 95% and an accuracy of 97%. According to the researchers, these results were about 20% better than bone scintigraphy, which is usually performed for this purpose.
"Whole-body MRI is a relatively new technique that uses an automatic moving table and fast software. It offers a better sensitivity and higher specificity in detecting bone metastasis than other methods," said Joan C. Vilanova, MD, lead researcher for the study.
In addition to all its benefits, say the researchers, whole-body MRI is not just limited to finding metastasis in the bone. "Besides its accuracy, quickness and the fact that it's an MRI scan—which means it's noninvasive and there is no radiation risk to the patient—whole-body MRI can also detect metastases in other parts of the body besides the bones, such as in the brain, lung or liver," said Dr. Vilanova.
Dr. Vilanova will present the full results of the study on May 16 during the American Roentgen Ray Society Annual Meeting in New Orleans, LA.
In a separate study that compared the results of whole-body MRI and whole-body FDG-PET for detecting cancer, researchers from the University Hospital in Freiburg, Germany, also found that whole-body MRI is fast and accurate for discovering bone metastases. However, they discovered that whole-body FDG-PET is superior to whole-body MRI in for staging lymph nodes, soft-tissue tumors, and metastasis in the internal organs.
For that study, the researchers scanned 120 patients using both whole-body MRI and whole-body FDG-PET. Similar to the Italian study, the whole-body MRI procedure took about 15 minutes total room time. They found that whole-body MRI detected 35 bone metastases, whereas whole-body FDG-PET discovered only 26. But MRI could only detect 63 of 68 lymph nodes, 15 of 19 soft-tissue tumors and 23 of 28 metastases in the internal organs, numbers below the detection rate of FDG-PET.
"In our experience, the combination of these two methods is the future in primary and recurrent tumor detection and staging," said Nadir Ghanem, MD, lead researcher on the German study.
Dr. Ghanem presented the full results of the study on May 17 during the American Roentgen Ray Society Annual Meeting in New Orleans, LA.