In vivo 1 H MRS is rapidly developing as a clinical tool for diagnosing and characterizing breast cancers. Many in vivo and in vitro experiments have demonstrated that alterations in concentrations of choline-containing metabolites are associated with malignant transformation. In recent years, considerable efforts have been made to evaluate the role of 1 H MRS measurements of total cholinecontaining compounds in the management of patients with breast cancer. Current technological developments, including the use of high-field MR scanners and quantitative spectroscopic analysis methods, promise to increase the sensitivity and accuracy of breast MRS. This article reviews the literature describing in vivo MRS in breast cancer, with an emphasis on the development of highfield MR scanning and quantitative methods. Potential applications of these technologies for diagnosing suspicious lesions and monitoring response to chemotherapy are discussed.

We report initial results with single voxel spectroscopy (SVS) using diffusion weighting and localization by adiabatic selective refocusing (LASER) in breast tumors to measure the apparent diffusion coefficient of water (ADCw). This is a quick ( Diagnosis of breast tumors is difficult, morphology on MRI or X-ray mammogram is not always sufficient, and biopsy is most often used as the final gold standard test (1). Secondary noninvasive tests can provide the physician with additional information, and perhaps in the future avoid unnecessary biopsy.Quantitative single voxel proton MRS for determining total concentration of choline-containing compounds, [tCho], has been shown to increase the diagnostic accuracy of MR in breast disease and provide an early indicator of tumor response to neoadjuvant chemotherapy (2,3). However, measurement of [tCho] is fraught with technical limitations due to low signal to noise ratio (SNR), motion, lipid overlap, artifactual sidebands, and shimming (4,5). The apparent diffusion coefficient of water (ADCw) is an additional MR-accessible parameter, which has already shown utility in cancer research (6 -9). Diffusion-weighted imaging (DWI) studies have demonstrated effectiveness in breast (10), although DWI has limitations as well. Echo planar DWI is fast, but limited in resolution and prone to distortion and motion artifacts. It also has SNR limitations, issues of image registration, and limits the number of b-values obtainable per voxel. Other MRI methods overcome some of these limitations but require more precious magnet time (11). All methods require overlay, comparison, and perhaps distortion correction to verify the region of interest (ROI). Single voxel ADCw (SV-ADCw) measurement, although lacking the ability to spatially resolve the region of interest retrospectively, offers the possibility of a rapid, simple, and high-SNR measurement. The purpose of this study is to demonstrate the feasibility of SV-ADCw in an initial patient population of 25 women as an additional diagnostic test for breast tumor malignancy. MATERIALS AND METHODSSpectroscopic and pathologic data from 25 women with breast abnormalities were reviewed. The study was approved by the Investigational Review Board at the University of Minnesota, and was HIPAA compliant. Before all studies, informed written consent was obtained. The patients ranged in age from 20 to 67 years (mean, 44.8 years) and were referred by radiologists, oncologists, and surgeons affiliated with the University of Minnesota. Patient age, diagnosis, tumor grade, axillary node status, and hormone receptor status were collected. For inclusion in this analysis patients had to meet the following criteria: (i) histologic confirmation of pathology (after breast MRI and MRS), (ii) an area of enhancement corresponding to mammographic and/or ultrasonographic abnormality, (iii) no significant motion during the scanning period, (iv) no prior surgical (including biopsy) or chemotherapeutic intervention in the breast of interest. For inclusion of [tCho] d...