Diffusion-Weighted Magnetic Resonance Imaging as a Cancer Biomarker: Consensus and Recommendations

Abstract

On May 3, 2008, a National Cancer Institute (NCI)-sponsored open consensus conference was held in Toronto, Ontario, Canada, during the 2008 International Society for Magnetic Resonance in Medicine Meeting. Approximately 100 experts and stakeholders summarized the current understanding of diffusion-weighted magnetic resonance imaging (DW-MRI) and reached consensus on the use of DW-MRI as a cancer imaging biomarker. DW-MRI should be tested as an imaging biomarker in the context of well-defined clinical trials, by adding DW-MRI to existing NCI-sponsored trials, particularly those with tissue sampling or survival indicators. Where possible, DW-MRI measurements should be compared with histologic indices including cellularity and tissue response. There is a need for tissue equivalent diffusivity phantoms; meanwhile, simple fluid-filled phantoms should be used. Monoexponential assessments of apparent diffusion coefficient values should use two b values (>100 and between 500 and 1000 mm2/sec depending on the application). Free breathing with multiple acquisitions is superior to complex gating techniques. Baseline patient reproducibility studies should be part of study designs. Both region of interest and histogram analysis of apparent diffusion coefficient measurements should be obtained. Standards for measurement, analysis, and display are needed. Annotated data from validation studies (along with outcome measures) should be made publicly available. Magnetic resonance imaging vendors should be engaged in this process. The NCI should establish a task force of experts (physicists, radiologists, and oncologists) to plan, organize technical aspects, and conduct pilot trials. The American College of Radiology Imaging Network infrastructure may be suitable for these purposes. There is an extraordinary opportunity for DW-MRI to evolve into a clinically valuable imaging tool, potentially important for drug development.

Correlation of the Apparent Diffusion Coefficient (ADC) with the Standardized Uptake Value (SUV) in Hybrid 18F-FDG PET/MRI in Non-Small Cell Lung Cancer (NSCLC) Lesions: Initial Results

“…In the present study we chose a range of three b-values (b0-b500-b1000), because the whole-body PET/MRI system is foremost designed for and used in oncologic applications. With our choice of b-values, we met the consensus recommendations on the use of DWI as an image biomarker in cancer patients [34]. Furthermore, as demonstrated previously in human brains, ADC values can be reliably calculated using only 2 b-values [35].…”

Comparison of diffusion‐weighted MRI and MR volumetry in the evaluation of early treatment outcomes after preoperative chemoradiotherapy for locally advanced rectal cancer

“…CRT induces tumor downstaging and complete/partial pathologic responses through vascular changes and cell death (1). However, individual responses to preoperative CRT have been shown to vary significantly and ineffective treatment may result in unnecessary toxicity to the patient as well as possibly delaying proper treatment (2).…”

Diffusion‐weighted and dynamic contrast‐enhanced MRI in evaluation of early treatment effects during neoadjuvant chemotherapy in breast cancer patients

“…The correlation between ADC values and treatment response has been investigated, and studies show an early increase in ADC after only one or two cycles of NAC (8,10). Guidelines for the use of DW-MRI as a cancer biomarker have been suggested, and emphasize the need for both validation and assessment of reliability of this method in oncologic imaging (11). The unique possibility of including several MR methods in one examination has made multiparametric studies of several tumor features possible; however, only a few studies have exploited this with respect to treatment response in breast cancer (12,13).…”