the WB-DWI scans
Photo courtesy of the
Institute of Cancer Research
A novel imaging technique could improve care for patients with multiple myeloma (MM) and reduce physicians’ reliance on bone marrow biopsies, according to researchers.
The group found that whole-body, diffusion-weighted imaging (WB-DWI) scans accurately showed the spread of MM throughout patients’ bone marrow.
And, most of the time, doctors were able to accurately determine which patients were responding to treatment by consulting the scans.
The investigators reported these results in Radiology.
They first performed WB-DWI on 8 healthy volunteers and 7 patients with MM, to assess the repeatability of quantitative apparent diffusion coefficient (ADC) estimates. ADC records how restricted water movement is within tissues.
The researchers found that ADC measurement was highly repeatable. The mean coefficient of variation was 3.8% in healthy volunteers and 2.8% in MM patients.
The team also performed pre-treatment WB-DWI scans on an additional 34 MM patients. Twenty-six of these patients had a post-treatment scan as well.
Physicians trained in imaging could pinpoint the exact sites of MM with WB-DWI, as the scans could show MM in nearly all bones. The skull remained difficult to image, however, partly because of the frequency of metal dental implants and fillings.
“This is the first time we’ve been able to obtain information from all the bones in the entire body for myeloma in 1 scan without having to rely on individual bone X-rays,” said study author Nandita deSouza, MD, of The Royal Marsden NHS Foundation Trust in the UK. “It enables us to measure the involvement of individual bones and follow their response to treatment.”
In 86% of cases, doctors were able to correctly identify whether patients responded to treatment. The physicians identified non-responders 80% of the time.
The investigators also assessed the visible changes on these scans using ADC. Changes in ADC correctly identified treatment response for 24 of 25 MM patients.
The mean ADC increased in 95% of responding patients and decreased in all non-responders (P=0.002). A 3.3% increase in ADC allowed the researchers to identify responding patients with 90% sensitivity and 100% specificity. An 8% increase in ADC yielded 70% sensitivity and 100% specificity.
The investigators said WB-DWI was suitable for more patients than conventional tests. For example, 7 patients had bone marrow biopsies, but their samples were inadequate for analysis.
“The scan is better than blood tests, which don’t tell us in which bones the cancer is located,” Dr deSouza said. “It also reduces the need for uncomfortable biopsies, which don’t reveal the extent or severity of the disease.”
The researchers did note that this study was conducted in a small number of patients. So the team plans to test the technology in more patients and refine the technique.
