INTRODUCTION We report initial experience with 3D mapping of tCho to monitor treatment response in patients undergoing neoadjuvant chemotherapy to predict outcome [1]. METHOD Eleven patients aged: 28 - 77 years with biopsy-confirmed, infiltrating ductal carcinoma (IDC) were studied before and during neoadjuvant therapy. Data were collected on a 3T MR scanner equipped with 8- and 16-channel breast array using PRESS volume prelocalized 3D high-speed Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) [2] with MEGA lipid suppression (TR/TE=2000ms/135ms, matrix size up to 32×16×8, voxel size=1cc, scan time: 10 minutes including a water reference scan). Spectral quantification was performed using LCModel-based spectral fitting in reference to tissue water [3] using a customized basis set with empirically modeled Lorentzian singlet peaks to account for broad and irregular line shapes of residual lipid signals, relaxation correction and automated spectral quality thresholds. RESULTS Strongly elevated tCho with mean concentrations up to 5.1 mmol/kg was measured in 7 patients with single and multi-centric enhancing lesions (Table 1). Decreases in tCho concentration and number of voxels with detectable tCho were measured in 4 patients who underwent neoadjuvant therapy. DISCUSSION AND CONCLUSION This study demonstrates feasibility of quantitative 3D mapping of tCho in invasive breast carcinoma and assessment of regional tCho changes during neoadjuvent therapy. The long-term goal is to utilize 3D high-speed MRSI as an early predictor of treatment failure in women undergoing neoadjuvant therapy. REFERENCES [1] Danishad, A., et al. NMR Biomed. 2010; 23: 233-241. [2] Posse, S., et al., Magn Reson Med, 1997. 37(6): p. 858-65. [3] Provencher et al MRM 1993. GRANT SUPPORT: NIH, DoD, UNM Cancer Center.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1710. doi:1538-7445.AM2012-1710