title: Earlier and better high-resolution single breast imaging during bilateral breast dynamic scans at 3-T MRI: comparison with post dynamic high-resolution imaging.
abstract: BACKGROUND
  Breast MRI protocols have been improved by using a combination of dynamic scans for bilateral breasts and high-resolution imaging for a single breast which can be obtained during dynamic scans by recent technological advances. The purpose of this study was to compare high-resolution imaging during dynamic scans (HR-intra) with high-resolution imaging obtained post dynamic scans (HR-post).
  
  
  METHODS
  Fifty-five women with pathologically proven breast cancer who underwent breast dynamic scans at 3-T MRI from February to September 2009 were enrolled in this study. Tumoral contrasts to the background breast tissue were compared by three radiologists independently in a blinded fashion. Results of visual assessment were categorized into three groups as follows: HR-intra being better (IB), equal (E), and HR-post being better (PB). The contrast to noise ratio (CNR) of the tumor and the signal to noise ratio of the normal breast gland (SNR) were compared between HR-intra and HR-post.
  
  
  RESULTS
  Two patients were excluded because of poor MR imaging quality. Three radiologists separately categorized 64.2, 79.2, and 77.4 % of lesions as IB. The CNR of the tumor of HR-intra (mean ± SD = 6.9 ± 4.0) was significantly higher than that of HR-post (6.0 ± 3.7, p < 0.0001). The SNR of the normal breast gland of HR-intra (9.5 ± 1.7) was significantly lower than that of HR-post (10.0 ± 1.9, p < 0.0001).
  
  
  CONCLUSIONS
  HR-intra during dynamic MRI provided earlier and better tumor to normal breast gland contrast than HR-post.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, N14, W5, Kita-ku, Sapporo, 060-8648, Japan.
authors.forename: Fumi
authors.initials: F
authors.lastname: Kato
authors.forename: Noriko
authors.initials: N
authors.lastname: Oyama-Manabe
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sakuhara
authors.forename: Suzuko
authors.initials: S
authors.lastname: Mito
authors.forename: Masato
authors.initials: M
authors.lastname: Takahashi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Mitsuchika
authors.initials: M
authors.lastname: Hosoda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Terae
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio