Early response of breast cancer bone metastases to chemotherapy evaluated with MR imaging

Purpose: To compare T1-weighted spin-echo and fat-suppressed long echo time inversion recovery turbo spin-echo (long TE IR-TSE) MR images in the evalu ation of early response of breast cancer bone metastases to chemotherapy. Material and Methods: Eighteen breast cancer patients with known bone metas tases were investigated prospectively by MR, using T1-weighted and long TE IR-TSE sequences on the sternum, spine, pelvis and proximal femora, before and after a median of 6 courses of chemotherapy. Therapeutic response evalu ation with MR was based on change in tumor size assessed quantitatively by measuring all focal metastases, and change in pattern and signal intensity (SI) of the metastases, assessed visually. Combined response evaluation bas ed on clinical findings, conventional radiography, and scintigraphy was use d as reference. Results: Progressive disease (2 patients) and no change (4 patients) were a ssessed equally well on both MR sequences. Long TE IR-TSE demonstrated part ial response with higher accuracy than T1-weighted images, 58% (7/12 patien ts) vs. 17% (2/12 patients). In patients without progression there was an S I increase in or around the metastases in 6 patients on T1-weighted images and in 7 patients on long TE IR-TSE images. Conclusion: The long TE IR-TSE sequence demonstrated early partial response of breast cancer bone metastases to chemotherapy more accurately than the T1-weighted sequence.