title: Study of normal breast tissue by in vivo volume localized proton MR spectroscopy: variation of water-fat ratio in relation to the heterogeneity of the breast and the menstrual cycle.
abstract: OBJECTIVE
  To investigate the alterations in water-fat (W-F) ratio of the normal breast tissue of female volunteers as a function of the histological phases of the menstrual cycle.
  
  
  METHODS
  Image-guided volume localized in vivo proton ((1)H) magnetic resonance spectroscopy (MRS) at 1.5 T was carried out in the para-areolar region and the upper and lower quadrants of the normal breast tissue of volunteers (n=29; mean age 33.7+/-6 years) during five histological phases of the menstrual cycle.
  
  
  RESULTS
  A W-F value of 0.90+/-0.41 was observed for the para-areolar region during the proliferative phase, which reduced to 0.46+/-0.21 and 0.45+/-0.25 during follicular and luteal phases, respectively. The value increased to 0.76+/-0.61 during secretory and to 0.87+/-0.37 during menstrual phases. No significant difference was observed in the W-F value for the upper and the lower quadrants of the breast during various phases of the menstrual cycle. However, the W-F ratio of the para-areolar region was significantly higher compared to the upper and the lower quadrants during all phases. This reflects the dependence of W-F value on the amount of glandular and adipose tissues and the heterogeneous nature of the breast.
  
  
  CONCLUSIONS
  Our results indicate that changes in the normal breast tissue characteristics occur due to physiological factors like menstrual cycle that strongly influences the W-F value especially the para-areolar region in a cyclic manner. Thus any assessment of breast pathology using W-F values should be carried out carefully taking into consideration the location of the tumor within the breast as well as the time of menstruation.
authors.affiliation: Department of NMR and MRI Facility, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: Uma
authors.initials: U
authors.lastname: Sharma
authors.forename: Mahesh
authors.initials: M
authors.lastname: Kumar
authors.forename: Rani G
authors.initials: RG
authors.lastname: Sah
authors.forename: Naranamangalam R
authors.initials: NR
authors.lastname: Jagannathan
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000502:physiology*; D000328:Adult; D001940:Breast / Q000033:anatomy & histology* / Q000378:metabolism*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008597:Menstrual Cycle / Q000378:metabolism*; D011522:Protons; D012016:Reference Values; D014018:Tissue Distribution; D014867:Water / Q000032:analysis / Q000378:metabolism*
chemical_list: D011522:Protons; D014867:Water