Assessment of treatment response by total tumor volume and global apparent diffusion coefficient using diffusion-weighted MRI in patients with metastatic bone disease: a feasibility study.
We describe our semi-automatic segmentation of whole-body diffusion-weighted MRI (WBDWI) using a Markov random field (MRF) model to derive tumor total diffusion volume (tDV) and associated global apparent diffusion coefficient (gADC); and demonstrate the feasibility of using these indices for assessing tumor burden and response to treatment in patients with bone metastases. WBDWI was performed on eleven patients diagnosed with bone metastases from breast and prostate cancers before and after anti-cancer therapies. Semi-automatic segmentation incorporating a MRF model was performed in all patients below the C4 vertebra by an experienced radiologist with over eight years of clinical experience in body DWI. Changes in tDV and gADC distributions were compared with overall response determined by all imaging, tumor markers and clinical findings at serial follow up. The segmentation technique was possible in all patients although erroneous volumes of interest were generated in one patient because of poor fat suppression in the pelvis, requiring manual correction. Responding patients showed a larger increase in gADC (median change = +0.18, range = -0.07 to +0.78 × 10(-3) mm2/s) after treatment compared to non-responding patients (median change = -0.02, range = -0.10 to +0.05 × 10(-3) mm2/s, p = 0.05, Mann-Whitney test), whereas non-responding patients showed a significantly larger increase in tDV (median change = +26%, range = +3 to +284%) compared to responding patients (median change = -50%, range = -85 to +27%, p = 0.02, Mann-Whitney test). Semi-automatic segmentation of WBDWI is feasible for metastatic bone disease in this pilot cohort of 11 patients, and could be used to quantify tumor total diffusion volume and median global ADC for assessing response to treatment.
Radiotherapy and Imaging Division, Cancer Research UK and Engineering and Physical Sciences Research Council Cancer Imaging Centre at The Institute of Cancer Research and The Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom.
Matthew D
MD
Blackledge
Radiotherapy and Imaging Division, Cancer Research UK and Engineering and Physical Sciences Research Council Cancer Imaging Centre at The Institute of Cancer Research and The Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom.
David J
DJ
Collins
Radiotherapy and Imaging Division, Cancer Research UK and Engineering and Physical Sciences Research Council Cancer Imaging Centre at The Institute of Cancer Research and The Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom.
Nina
N
Tunariu
Radiotherapy and Imaging Division, Cancer Research UK and Engineering and Physical Sciences Research Council Cancer Imaging Centre at The Institute of Cancer Research and The Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom.
Matthew R
MR
Orton
Paul Strickland Scanner Centre, Mount Vernon Cancer Centre, Northwood, Middlesex, United Kingdom.
Anwar R
AR
Padhani
Radiotherapy and Imaging Division, Cancer Research UK and Engineering and Physical Sciences Research Council Cancer Imaging Centre at The Institute of Cancer Research and The Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom.
Martin O
MO
Leach
Radiotherapy and Imaging Division, Cancer Research UK and Engineering and Physical Sciences Research Council Cancer Imaging Centre at The Institute of Cancer Research and The Royal Marsden National Health Service Foundation Trust, Sutton, United Kingdom.
Dow-Mu
DM
Koh
D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary / Q000628:therapy; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy; D011859:Radiography; D047368:Tumor Burden