ORIGINAL ARTICLE Evaluation of 1 H-Magnetic Resonance Spectroscopy of Breast Cancer Pre- and Postgadolinium Administration Bonnie N. Joe, MD, PhD,* Victoria Y. Chen, MD,§ Nouha Salibi, PhD,† Pornpim Fuangtharntip, MD,‡ Charles F. Hildebolt, DDS, PhD,§ and Kyongtae T. Bae, MD, PhD§ Objectives: We sought to evaluate spectroscopic measurements in breast cancer and compare variability in choline peak parameters related to contrast administration versus that inherent to repeated measurements. Materials and Methods: Single-voxel, proton spectroscopy mea- surements were obtained before and after the administration of gadolinium on 15 patients with 1-cm breast cancers. The protocol was repeated on a separate day in 7 patients. Results: Postcontrast spectra demonstrated a significant increase in choline peak linewidth (day 1: 15%  21%, P = 0.03; day 2: 19%  12%, P = 0.001) and decrease in choline peak area (day 1: 11%  9% (P  0.001); day 2: 18%  21% (P = 0.03). A variance-components analysis indicated that day-to-day variation in linewidth accounted for 0.0% of the total variation in width mea- surements and was not significant (P = 0.85). Day-to-day variation in area was also not significant (0.0%, P = 0.95). Conclusions: Contrast administration caused significant increases in choline peak linewidth and decreases in choline peak area in spec- troscopic measurements of breast cancer. Key Words: MR spectroscopy, breast cancer, breast MRI, contrast, choline (Invest Radiol 2005;40: 405– 411) O ne of the criticisms of breast magnetic resonance imag- ing (MRI) is that the findings are frequently nonspecific. Dynamic contrast-enhancement patterns and lesion morphol- ogy can be helpful in distinguishing benign from malignant masses, but these features are not perfect predictors and there may be considerable variability in their interpretation. 1 Hence, many groups are actively investigating methods for improving the diagnostic specificity of contrast-enhanced breast MRI. 2–7 A promising method to study the biochemistry of breast tumor cells in vivo is proton magnetic resonance spectros- copy ( 1 H-MRS). In theory, combining 1 H-MRS and dynamic gadolinium-enhanced MRI may make the findings of breast MRI more specific. The relative importance, however, of the effect of circulating gadolinium on spectroscopic measure- ments in breast tumors is still unresolved. Kvistad et al 8 waited more than 7 hours after the administration of gado- linium before performing 1 H-MR spectroscopic measure- ments because of concerns that circulating gadolinium might hinder the detection of choline-containing compounds. Work performed on brain tumors has shown a decrease in signal intensity of the choline resonance (a commonly measured peak in spectroscopic studies of malignancies) in 1 H-MR spectra after gadolinium administration. 9 An in vitro study has also demonstrated that gadolinium can affect proton relaxivities of choline, as well as other brain metabolites, and thus affect signal intensity. 10 No similar studies have been reported with respect to breast tumors. The purpose of this study was to compare the variabil- ity between pre- and postcontrast spectroscopic measure- ments to the inherent interscan variability in repeated spec- troscopic measurements. Leach et al 11 reported variability in repeated 31 P spectroscopic measurements of total phosphate of 6% for 2 patients measured on the same day and 29% for 2 patients measured on different days. To our knowledge, no study of interscan variability with 1 H-MR spectroscopic mea- surements has been performed. Our hypothesis was that the inherent interscan variability in spectroscopic measurements would be comparable to if not greater than the variability introduced by gadolinium administration. Support of this Received December 20, 2004 and accepted for publication, after revision, March 22, 2005. From the *Department of Radiology, University of California, San Fran- cisco; †Siemens Medical Solutions, Inc., Malvern, Pennsylvania; ‡De- partment of Radiology, Siriraj Hospital, Mahidol University, Bangkok, Thailand; and §Mallinckrodt Institute of Radiology, Washington Univer- sity School of Medicine, St. Louis, Missouri. Supported by the RSNA Research and Education Foundation, Amersham Health (Princeton, NJ), and Becton Dickinson (Franklin Lakes, NJ). Reprints: Bonnie N. Joe, MD, PhD, Abdominal Imaging, Department of Radiology, University of California San Francisco, Box 0628, L-325B, 505 Parnassus Avenue, San Francisco, CA 94143-0628. E-mail: bonnie. joe@radiology.ucsf.edu. Copyright © 2005 by Lippincott Williams & Wilkins ISSN: 0020-9996/05/4007-0405 Investigative Radiology • Volume 40, Number 7, July 2005 405