Abstract | OBJECTIVE:
Gallstones are usually recognized on MRI as filling defects of hypointensity. However, they sometimes may appear as hyperintensities on T1-weighted imaging. This study investigated how gallstones appear on MRI and how their appearance influences the detection of gallstones. MATERIALS AND METHODS:
Gallstones from 24 patients who had MRI performed before the removal of the gallstones were collected for study. The gallstones were classified either as cholesterol gallstone (n = 4) or as pigment gallstone (n = 20) according to their gross appearance and based on analysis by Fourier transform infrared spectroscopy. MRI included three sequences: single-shot fast spin-echo T2-weighted imaging, 3D fast spoiled gradient-echo T1-weighted imaging, and in-phase fast spoiled gradient-echo T1-weighted imaging. The signal intensity and the detection rate of gallstones on MRI were further correlated with the character of the gallstones. RESULTS: On T1-weighted 3D fast spoiled gradient-echo images, most of the pigment gallstones (18/20) were hyperintense and all the cholesterol gallstones (4/4) were hypointense. The mean ratio of the signal intensity of gallstone to bile was (+/- standard deviation) 3.36 +/- 1.88 for pigment gallstone and 0.24 +/- 0.10 for cholesterol gallstone on the 3D fast spoiled gradient-echo sequence (p < 0.001). Combining the 3D fast spoiled gradient-echo and single-shot fast spin-echo sequences achieved the highest gallstone detection rate (96.4%). CONCLUSION: Based on the differences of signal intensity of gallstones, the 3D fast spoiled gradient-echo T1-weighted imaging was able to diagnose the composition of gallstones. Adding the 3D fast spoiled gradient-echo imaging to the single-shot fast spin-echo T2-weighted sequence can further improve the detection rate of gallstones.
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Authors | Hong-Ming Tsai, Xi-Zhang Lin, Chiung-Yu Chen, Pin-Wen Lin, Jui-Che Lin |
Journal | AJR. American journal of roentgenology
(AJR Am J Roentgenol)
Vol. 182
Issue 6
Pg. 1513-9
(Jun 2004)
ISSN: 0361-803X [Print] United States |
PMID | 15149998
(Publication Type: Journal Article)
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Chemical References |
- Pigments, Biological
- Cholesterol
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Topics |
- Adult
- Aged
- Aged, 80 and over
- Cholesterol
(analysis)
- Female
- Gallstones
(chemistry, diagnosis)
- Humans
- Magnetic Resonance Imaging
- Male
- Middle Aged
- Pigments, Biological
(analysis)
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