New type of MRI ‘whole body’ scan could improve treatment of bone-marrow cancer

February 19, 2014

Patient setup for WB-DWI (credit: Institute of Cancer Research)

A new type of magnetic resonance imaging (MRI) scan could improve care for a type of cancer called myeloma and reduce reliance on bone marrow biopsies, which can be painful for patients and often fail to show doctors how far the disease has spread.

The research, published Feb. 18 in the journal Radiology, was carried out by researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust.

The new whole-body, diffusion-weighted MRI scans showed the spread of cancer throughout the bone marrow of patients with myeloma — one of the most common forms of blood cancer — more accurately than standard tests. The scans also showed whether the patients were responding to cancer treatments.

In the study, 26 patients had whole-body, diffusion-weighted MRI scans before and after treatment. In 86% of cases, experienced doctors trained in imaging were able to correctly identify whether patients responded to treatment. The doctors also correctly identified those patients who weren’t responding to treatment 80% of the time.

Using the scanning technique, doctors could pinpoint exactly where the cancer was in the bones, with the results available immediately. Conventional tests include bone marrow biopsies and blood tests but neither shows accurately where the cancer is present in the bones.

The researchers also assessed the visible changes on the MRI scans, using a measurement called the Apparent Diffusion Coefficient (ADC), which records how restricted water movement is within tissues. Changes in this measurement correctly identified treatment response for 24 of 25 myeloma patients.

The new scan was able to visualize cancer in almost all bones in the body, with only the skull remaining difficult to image, partly because of metal dental implants and fillings. The researchers also found the new methods were suitable for more patients than conventional tests; for example, seven patients had bone marrow biopsies but their samples were found to be inadequate for analysis. Performing another biopsy could be traumatic and painful, and may not provide any new information.

“This is the first time we’ve been able to obtain information from all the bones in the entire body for myeloma in one scan without having to rely on individual bone X-rays,” Professor Nandita deSouza, Professor of Translational Imaging at The Institute of Cancer Research and Honorary Consultant at The Royal Marsden, said. ” It enables us to measure the involvement of individual bones and follow their response to treatment.

“The results can be visualized immediately; we can look on the screen and see straight away where the cancer is and measure how severe it is. The scan is better than blood tests, which don’t tell us in which bones the cancer is located. It also reduces the need for uncomfortable biopsies, which don’t reveal the extent or severity of the disease.”

The research received funding from Cancer Research UK and the National Institute for Health Research Clinical Research Facility in Imaging, with additional funding from the EPSRC.

Abstract of Radiology paper

Purpose – To determine the feasibility of whole-body diffusion-weighted (DW) magnetic resonance (MR) imaging for assessment of treatment response in myeloma.
Materials and Methods – This prospective single-institution study was HIPAA-compliant with local research ethics committee approval. Written informed consent was obtained from each subject. Eight healthy volunteers (cohort 1a) and seven myeloma patients (cohort 1b) were imaged twice to assess repeatability of quantitative apparent diffusion coefficient (ADC) estimates. Thirty-four additional myeloma patients (cohort 2) underwent whole-body DW imaging before treatment; 26 completed a posttreatment imaging. Whole-body DW data were compared before and after treatment by using qualitative (ie, observer scores) and quantitative (ie, whole-body segmentation of marrow ADC) methods. Serum paraproteins and/or light chains or bone marrow biopsy defined response.
Results – Whole-body DW imaging scores were significantly different between observers (P < .001), but change in scores between observers after treatment was not (P = .49). Sensitivity and specificity for detecting response according to observer scores were 86% (18 of 21 patients) and 80% (4 of 5 patients) for both observers. ADC measurement was repeatable: mean coefficient of variation was 3.8% in healthy volunteers and 2.8% in myeloma patients. Pretreatment ADC in cohort 2 was significantly different from that in cohort 1a (P = .03), but not from that in cohort 1b (P = .2). Mean ADC increased in 95% (19 of 20) of responding patients and decreased in all (five of five) nonresponders (P = .002). A 3.3% increase in ADC helped identify response with 90% sensitivity and 100% specificity; an 8% increase (greater than repeatability of cohort 1b) resulted in 70% sensitivity and 100% specificity. There was a significant negative correlation between change in ADC and change in laboratory markers of response (r = −0.614; P = .001).
Conclusion – Preliminary work demonstrates whole-body DW imaging is a repeatable, quantifiable technique for assessment of treatment response in myeloma.