P2-10-04: 3D Mapping of Total Choline in Human Breast Cancer Using High-Speed MR Spectroscopic Imaging at 3T: A Feasibility Study.

Abstract

Abstract PURPOSE: To assess the feasibility of quantitative high-speed MR spectroscopic imaging (MRSI) of total Choline (tCho) as an adjunct to dynamic-contrast enhanced (DCE) MRI to improve lesion characterization and monitor treatment response in patients undergoing neoadjuvant chemotherapy. METHOD AND MATERIALS: Seven patients with biopsy-confirmed, infiltrating ductal carcinoma were studied using a clinical 3T MR scanner (Siemens Medical Solutions, Erlangen, Germany) equipped with 8- and 16-channel breast array (Hologic Inc., Bedford, MA). Measurements were performed using PRESS prelocalized 3D Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) using TR/TE=2000ms/135ms, matrix size up to 32×16x8, voxel size=1cc, and total acquisition time of 10 minutes (including water reference scan). Additional data were collected at TE 60 ms to enhance sensitivity for detecting tCho and J-coupled resonances. TE-averaging (8 steps, ΔTE: 2.5 ms) was employed to minimize gradient sideband artifacts. Quantification of tCho in reference to tissue water was performed using spectral fitting and relaxation correction. RESULTS: Strongly elevated tCho with maximum concentration ranging from 0.3 to 4.1 mmol/kg was measured in five patients with single and multi-centric enhancing lesions larger than 2 cc volume (Table 1). The measured tCho concentration in Grade 3 tumors was higher than in lower grade untreated and treated tumors. Strong decreases in tCho concentration were measured in 2 patients undergoing neoadjuvant therapy in a follow-up scan. At short TE an additional resonance was detected that was elevated in enhancing lesions and tentatively assigned to Taurine. Two patients had lesions smaller than 2 cc with surgical clips in which tCho was not detectable due to line broadening. MRSI data sets were preferentially collected before contrast injection, since it increased spectral line width by up to 50%. CONCLUSION: This study demonstrates feasibility of quantitatively mapping tCho in invasive breast carcinoma using high-speed MRSI. The long-term goals are to utilize high-speed MRSI as an early predictor of treatment failure in women undergoing neoadjuvant therapy (i.e. chemotherapy, endocrine therapy or biologic therapy) for breast cancer and to develop an improved screening protocol for high-risk patients. Grant support: 1RC1EB010617-01 Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-10-04.