title: A comparison of shimming techniques for optimizing fat suppression in MR mammography.
abstract: We evaluated the degree of inhomogeneities of fat suppression using the fully automated three-dimensional breast shimming technique (Image Based-Smart: IB-Smart) and manual setting of a rectangular parallelepiped shim (volume shimming) in MR mammography. Information on breast shape was collected from 9 patients whose images were insufficiently fat-suppressed. A breast phantom made of a thermoplastic sheet was used. Shimming of the magnetic field was done with IB-Smart and various dimensions of volume shims: the anterior to posterior/right to left/head to foot directions were set to 75-150/150-350/50-150 mm. The volumes of inhomogeneously suppressed fat were measured. The calculated volume with inhomogeneous fat suppression with use of IB-Smart was 13.3 × 10(4) mm(3). The smallest volume of inhomogeneous fat suppression with volume shimming was 5.4 × 10(4) mm(3) when the anterior-posterior/right-left/head-foot directions were set to 75/350/50 mm. Our results show that using optimized dimensions of volume shims enables better fat suppression than does IB-Smart.
authors.affiliation: Department of Radiology, Osaka Red Cross Hospital, 5-30 Fudegasaki, Tennouji-ku, Osaka 543-8555, Japan. pcblue2@yahoo.co.jp
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Takatsu
authors.forename: Kengo
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Tosiaki
authors.initials: T
authors.lastname: Miyati
authors.forename: Hideto
authors.initials: H
authors.lastname: Miyano
authors.forename: Mariko
authors.initials: M
authors.lastname: Kajihara
authors.forename: Thai
authors.initials: T
authors.lastname: Akasaka
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D001940:Breast / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008327:Mammography; D019047:Phantoms, Imaging