A spate of European studies within the last year contributes to the evidence that MRI may soon replace scintigraphy and x-ray to detect bony metastases and soft tissue involvement.

In one study, Dr. Frédéric E. Lecouvet, professor of musculoskeletal radiology, Saint Luc University Hospital, Brussels, and his colleagues prospectively enrolled 66 consecutive patients with a high-risk prostate cancer profile who underwent MRI of the spine and pelvis in addition to a standard sequential imaging workup. The imaging workup included technetium-99m bone scintigraphy, targeted x-rays in patients with inconclusive bone scans, and on-request MRI in patients with inconclusive bone scans and x-rays (J Clin Oncol 25:3281-3287, 2007).

They found that MRI alone was more sensitive (100%) than the combination of the other tests (63%). MRI's specificity (88%) also topped the combination of the other tests (64%). MRI modified therapy by finding metastases in about one-third of patients considered negative and almost half of those with inconclusive results by standard imaging.

The MRI technique—detection of foci of abnormal signal intensity on T1- and T2-weighted fat-saturated images—is quite simple, Dr. Lecouvet said. He added that a larger multicenter trial is under way to assess reproducibility.

Whole-body MRI

Dr. Joan Vilanova, from the Ressonáncia Girona MRI Clinic in Spain, found whole-body MRI more sensitive and specific than scintigraphy in detecting bone metastases in 24 patients. MRI also provided additional information regarding nonskeletal lesions, especially in the lungs, liver, and lymph nodes, Dr. Vilanova reported at last year's RSNA annual meeting.

Dr. Stephen Eustace, professor of musculoskeletal radiology, Cappagh National Orthopaedic Hospital, Dublin, says that whole-body MRI should now be regarded as the test of choice for staging skeletal metastatic disease.