Diagnosis of gallstone composition in magnetic resonance imaging: in vitro analysis.
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.
Ukaji
Minoru
M
First Department of Medicine, School of Medicine, Chiba University, Japan. akiukaji@mrg.biglobe.ne.jp
Ebara
Masaaki
M
Tsuchiya
Yukihiro
Y
Kato
Hirotoshi
H
Fukuda
Hiroyuki
H
Sugiura
Nobuyuki
N
Saisho
Hiromitsu
H
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
D003300:Copper; D002784:Cholesterol; D007501:Iron; D002119:Calcium Carbonate