title: Diagnosis of gallstone composition in magnetic resonance imaging: in vitro analysis.
abstract: OBJECTIVE
  To elucidate the cause of the signal intensity of gallstones on magnetic resonance (MR) images and to determine whether MR imaging would enable the prediction of the composition of gallstones.
  
  
  METHODS
  50 gallstones removed by cholecystectomy from 50 patients were used for in vitro study. All 50 gallstones were examined by MR imaging using a body phantom. After imaging, all gallstones were cut into two pieces, and the MR appearances were compared with their cross-sections. Chemical analysis was subsequently performed on 32 gallstones.
  
  
  RESULTS
  On T2-weighted (T2W) images, 24 of 50 gallstones showed high signal intensities only in their center. These central high intensities seen on T2W images corresponded to the clefts filled with fluid within gallstones. In 45 of 50 gallstones there were high signal intensity areas in central and/or peripheral regions on T1-weighted (T1W) images. On T1W images, not only the clefts within gallstones but also other regions were seen as high intensity, and these regions had a brown to black color, coarse structure, and contained much copper.
  
  
  CONCLUSIONS
  MR imaging can visualize the structures and compositions of gallstones in detail.
authors.affiliation: First Department of Medicine, School of Medicine, Chiba University, Japan. akiukaji@mrg.biglobe.ne.jp
authors.forename: Minoru
authors.initials: M
authors.lastname: Ukaji
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ebara
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Kato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukuda
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Sugiura
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Saisho
mesh_terms: D002119:Calcium Carbonate / Q000032:analysis; D002769:Cholelithiasis / Q000737:chemistry*; D002784:Cholesterol / Q000032:analysis; D003300:Copper / Q000032:analysis; D006801:Humans; D066298:In Vitro Techniques; D007501:Iron / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008961:Models, Structural; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted
chemical_list: D003300:Copper; D002784:Cholesterol; D007501:Iron; D002119:Calcium Carbonate