Multiparametric bone MRI can improve CT-guided bone biopsy target selection in cancer patients and increase diagnostic yield and feasibility of next-generation tumour sequencing.

Objectives: To evaluate whether multiparametric bone MRI (mpBMRI) utilising a combination of DWI signal, ADC and relative fat-fraction (rFF) can identify bone metastases, which provide high diagnostic biopsy yield and next-generation genomic sequencing (NGS) feasibility.

Methods: A total of 150 CT-guided bone biopsies performed by interventional radiologists (3/2013 to 2/2021) at our centre were reviewed. In 43 patients, contemporaneous DWI and rFF images, calculated from 2-point T1w Dixon MRI, were available. For each biopsied lesion, a region of interest (ROI) was delineated on ADC and rFF images and the following MRI parameters were recorded: visual classification of DWI signal intensity (SI), mean, median, 10th and 90th centile ADC and rFF values. Non-parametric tests were used to compare values between tumour positive/negative biopsies and feasible/non-feasible NGS, with p-values < 0.05 deemed significant.

Results: The mpBMRI combination high DWI signal, mean ADC < 1100 µm/s and mean rFF < 20% identified tumour-positive biopsies with 82% sensitivity, 80% specificity, a positive predictive value (PPV) of 93% (p = 0.001) and NGS feasibility with 91% sensitivity, 78% specificity and 91% PPV (p < 0.001). The single MRI parameters DWI signal, ADC and rFF failed to distinguish between tumour-positive and tumour-negative biopsies (each p > 0.082). In NGS feasible biopsies, mean and 90th centile rFF were significantly smaller (each p < 0.041). Single ADC parameters did not show significant difference regarding NGS feasibility (each p > 0.292).

Conclusions: MpBMRI utilising the combination of DWI signal, ADC and rFF can identify active bone metastases, which provide biopsy tissue with high diagnostic yield and NGS feasibility.

Key Points: • Multiparametric bone MRI with diffusion-weighted and relative fat-fraction images helps to identify active bone metastases suitable for CT-guided biopsy. • Target lesions for CT-guided bone biopsies in cancer patients can be chosen with greater confidence. • CT-guided bone biopsy success rates, especially yielding sufficient viable tissue for advanced molecular tissue analyses, can be improved.