Whole-body MRI lures musculoskeletal imagers

Whole-body MR could complement - in some cases, even replace altogether - traditional bone scanning techniques, according to studies from Germany, Italy, and Spain released at the 2006 RSNA meeting in Chicago.

Researchers from the Institute of Radiology at the University of Pavia in Italy compared whole-body MRI with an x-ray-based skeletal survey for staging of multiple myeloma in 107 consecutive patients. They found whole-body MR more sensitive and specific for this task. They also found that MR results changed patient management in a significant number of patients, leading to an overall cost reduction.

Whole-body MRI revealed more extensive involvement than did the x-ray skeletal survey in 91% of patients with positive findings. Both imaging techniques showed a similar extent of bone marrow involvement in almost 9% of patients. X-rays, however, came up with a higher false-positive rate. Whole-body MR imaging results changed clinical management in more than 24% of patients.

"Whole-body MR can easily demonstrate bone marrow alterations," said principal investigator Michela Zacchino. "We recommend it for routine management of multiple myeloma patients."

A study by Dr. Andreas Baldauf from the University of Heidelberg in Germany also compared whole-body MRI with conventional radiography for the diagnosis and staging of multiple myeloma in 41 consecutive patients. Baldauf and colleagues found whole-body MRI provided a significant impact on staging and patient management. Long-term follow-up of this population may confirm whole-body MRI's value as the method of choice for staging, Baldauf said.

MR imaging changed disease staging in 27 patients, with 12 and 15 patients classified at higher and lower stages, respectively, than with previous evaluations. In many cases, MR did not confirm signs of local or bone marrow infiltration seen on conventional radiography. MRI also identified myeloma foci and soft-tissue masses that went undetected by x-rays. MR staging changed management indications for three patients requiring treatment and eight who did not.

Dr. Joan Vilanova from the Ressonància Girona MRI Clinic in Spain presented results of another study comparing the diagnostic value of whole-body MRI with bone scintigraphy in 24 patients with metastatic bone disease. Vilanova and colleagues found the whole-body MR scanning technique significantly more sensitive and specific than scintigraphy for detection of bone metastases.

Whole-body MRI detected 96% of metastases from skeletal sites, while scintigraphy revealed only 52%. Sensitivity, specificity, and accuracy for whole-body MR were 100%, 90%, and 96%, respectively, and for scintigraphy they were 71%, 80%, and 75%, respectively. Whole-body MR showed additional metastases in extraskeletal regions of the body in 42% of patients with bone metastases.

Diffusion-weighted imaging with whole-body MR detected all bone lesions - except osteoblastic metastases - and all extraskeletal lesions.

Whole-body MRI could be applied in several other ways. It provides an imaging alternative for diagnosis of multisystemic infections and multiple myeloma. It could also detect and provide additional information regarding nonskeletal lesions, especially in the lungs, liver, and lymph nodes.

The complete evaluation takes less than 40 minutes, can replace the need for bone scintigraphy in most cases, and complements PET studies, Vilanova said.

"We are starting to use whole-body MR with our oncologists, who feel very confident about it. They are now asking us to perform whole-body MR instead of scintigraphy in certain protocols," he said.

For more information from the Diagnostic Imaging archives:

Experience overcomes difficulties of 3T MRI

Whole-body MR proves value in lymphoma staging

MRI enhances whole-body imaging

Whole-body MR shows clinical promise, but not for screening