Original contribution Proton MR spectroscopy of normal breasts: Association of risk factors for breast cancer with water and lipid composition of the breast ☆ Jane Wang a, b, c , Ming-Yang Wang d , Wen-Hung Kuo d , Kuan-Lin Chen a , Tiffany Ting-Fang Shih a, b, ⁎ a Department of Medical Imaging, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 100, Taiwan, ROC b Department of Radiology, National Taiwan University College of Medicine, 1, Section 1, Jen-Ai Road, Taipei 100, Taiwan, ROC c Department of Radiology, Taipei Veterans General Hospital, 201, Section 2, Shipai Road, Taipei 112, Taiwan, ROC d Department of Surgery, National Taiwan University Hospital, Taipei 100, Taiwan, ROC abstract article info Article history: Received 20 November 2015 Accepted 15 December 2015 Keywords: Proton magnetic resonance spectroscopy Water fraction Lipid line width Normal breasts Purpose: To investigate the water and lipid composition of normal women breasts on proton MR spectroscopy ( 1 H-MRS), and the association of breast cancer risk factors with 1 H-MRS parameters. Materials and methods: Three groups of participants were included: group 1, women without a family history of breast cancer (n = 49); group 2, women with at least one affected first-degree relative (n = 77); group 3, contralateral normal breasts of women with newly diagnosed unilateral breast cancer (n = 84). 1 H-MRS parameters were shown below: water fraction 1 (WF1) = (water integral)/ (water integral + integral for methylene peak); lipid line width for methylene resonance (LW1) and lipid line width for methyl peaks (LW2) were measured. The association of breast cancer risk factors – age, breast density, body mass index (BMI), menopausal status, group with 1 H-MRS parameters – was analyzed by multiple linear regression. Results: In age-adjusted multiple linear regression, breast density was positively associated with WF1 (P = 0.009, 0.001, and b 0.001 for groups 1, 2, and 3, respectively). BMI was inversely associated with LW1 in groups 1 (P = 0.040) and 3 (P = 0.005). In group 3, premenopausal breasts had lower LW2 than their postmenopausal counterparts (P = 0.033). Group 3 had narrower LW2 than group 2 (P = 0.007). Conclusions: The risk factors for breast cancer were associated with 1 H-MRS parameters. © 2015 Elsevier Inc. All rights reserved. 1. Introduction Breast magnetic resonance imaging (MRI) is a sensitive modality for breast cancer diagnosis [1–6]. Breast density is an independent risk factor for breast cancer, and breast MRI with 3-dimensional segmentation is used to determine breast density [7–10]. Use of MRI to investigate the chemical composition of normal breasts is rarely reported [11–15]. Graham et al. [11] estimated the volumetric water content of ex vivo normal breast tissue to infer the fibroglandular volume. Changes in lipid composition, water content, and fibro- glandular volume during the menstrual cycle evaluated by breast MRI have also been reported, and proton MR spectroscopy ( 1 H-MRS) was used in some of those studies [15–17]. 1 H-MRS is commonly used as an adjunct to breast MRI since the presence of a choline peak in breast tumors is an indicator of malignancy [18–21]. It was reported that different lipid composition revealed different implica- tions in normal breasts on 1 H-MRS [14]. However, use of 1 H-MRS to investigate the chemical composition of normal breasts for risk stratification is not clearly documented. Women with a family history of breast cancer, especially in affected first-degree relatives, are at higher risk for breast cancer than the general population, with a pooled relative risk of about 1.8–2.1 for one affected first-degree relative and about 2.9 for two affected first-degree relatives [22–24]. There is also an increased risk of breast cancer in the contralateral breasts of women with recently diagnosed unilateral breast cancer, with an annual incidence of 0.5%– 1.0% and a cumulative incidence of about 15% at 20 years [3,25]. Other reported risk factors for breast cancer included age, body mass index (BMI), hormonal factors, and a history of high-risk pathologies such as atypical ductal hyperplasia (ADH), lobular neoplasia, and so forth [26]. In our study, we estimated the chemical composition of normal breasts by 1 H-MRS from three groups of women — one group without any family history of breast cancer, one group with at least one affected first-degree relative, and one group with unilateral breast cancer in which the contralateral normal breasts were studied. We investigated whether risk factors for breast cancer are associated with 1 H-MRS findings in normal breasts. Magnetic Resonance Imaging 34 (2016) 524–528 ☆ The work was done in National Taiwan University Hospital, Taipei, Taiwan. ⁎ Corresponding author. Tel.: +886 2 23123456 65568; fax: +886 2 23224552. E-mail addresses: jwwangjen@gmail.com (J. Wang), suryang1971@hotmail.com (M.-Y. Wang), npcancer@yahoo.com.tw (W.-H. Kuo), step01.tw@gmail.com (K.-L. Chen), ttfshih@ntu.edu.tw (T T.-F. Shih). http://dx.doi.org/10.1016/j.mri.2015.12.028 0730-725X/© 2015 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Magnetic Resonance Imaging journal homepage: www.mrijournal.com