Monitoring of early response to neoadjuvant chemotherapy in breast cancer with 1H MR spectroscopy:: Comparison to sequential 2-[18F]-fluorodeoxyglucose positron emission tomography

Purpose: To assess the efficacy of H-1 MR spectroscopy (MRS) to evaluate early responses to neoadjuvant chemotherapy in breast cancer patients, as compared to that of the standardized uptake value (SUV) in '$F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Materials and Methods: This retrospective study included seven patients with breast cancer who had both single-voxel 'H MRS and PET/computed tomography (CIA acquired before, during, and after neoadjuvant chemotherapy. Results: The averages of the Choline (Cho) integral value and peak SUV before chemotherapy were 2.5 (range, 1.25.3) and 7.5 (range, 1.9-19), respectively. Three cases became negative for both Cho and peak SUV after two cycles of chemotherapy, and one patient became negative before surgery. In the remaining three patients, the curves of both values paralleled the time course of chemotherapy treatment. The difference between Cho and peak SUV before, during, and after chemotherapy was r = 0.65 (P = 0.12), r = 0.80 (P = 0.03), and r = 0.99 (P < 0.001), respectively. The reduction rate (RR) of both values after chemotherapy was also correlated (r = 0.84, P = 0.02). Conclusion: A change in the Cho integral value is well correlated with that of peak SUV in the time course of neoadjuvant chemotherapy; thus, breast 'H MRS is thought to be an alternative to sequential ' $F-FDG PET.