Blood oxygen level-dependent MRI for the monitoring of neoadjuvant chemotherapy in breast carcinoma: initial experience

Purpose: To determine the feasibility of using R2* map MRI for pretreatment diagnosis and monitoring of tumor response to neoadjuvant chemotherapy (NAC) in patients with breast cancer. Material and Methods: Twenty-eight women with breast cancer, as evidenced by pathology, underwent MR imaging prior to and after chemotherapy. All patients were examined by conventional MRI and R2* map imaging. Subjects were divided into major histological response (MHR) and non-major histological response (NMHR) groups. Mean R2* values of cancerous and normal glandular tissues were measured before and following NAC. Differences in R2* and Delta R2*% values between these two groups were compared with paired or independent t tests. The relationship between Delta R2*% and histological response was examined using Spearman's correlation test. Results: Before NAC, the average R2* values in carcinoma were lower than in normal glandular tissue (P<.05). After two to four cycles of NAC, the R2* values in carcinoma were increased (P<.05), but this change was not significant in normal glandular tissue. After NAC, Delta R2*% was significantly higher in MHR as compared to NMHR (P<.05). The Delta R2*% correlated with the histological response (r=0.581, P<.01). Conclusion: In women undergoing NAC for breast cancer treatment, R2* and Delta R2*% appear to provide predictive information of tumor response which is probably associated with changes in tumor angiogenesis and tissue oxygenation. R2* map imaging of breasts may therefore be useful in monitoring tumor response to NAC. (C) 2011 Elsevier Inc. All rights reserved.