Value of adding T1-weighted image to MR cholangiopancreatography for detecting intrahepatic biliary stones.
OBJECTIVE
The purpose of this study was to assess the value of adding a T1-weighted image to MR cholangiopancreatography (MRCP) to detect bile duct stones.


METHODS
During a 30-month period, 148 patients suspected of having biliary stones and who underwent MRI including MRCP, a fat-suppressed T1-weighted fast low-angle shot (FLASH) sequence, and an axial HASTE sequence were enrolled in this study. The biliary stones were confirmed by ERCP, surgery, and percutaneous transhepatic cholangiography. Of these 148 patients, 73 had extrahepatic stones, 45 had intrahepatic stones, 20 had both extrahepatic and intrahepatic stones, and 10 had no biliary stones. Two separate sets of images, the MRCP set (composed of MRCP and axial HASTE) and the combined interpretion of the MRCP set and the T1-weighted image, were analyzed independently and separately by two observers. The diagnostic accuracy was evaluated using the receiver operating characteristic method. The sensitivity and specificity were also calculated.


RESULTS
For common duct stones, the diagnostic accuracy and the sensitivity of both image sets showed similar values without any significant difference (0.998 [97.8%] for the combined interpretation; 0.988 [97.8%] for observer 1 and 0.995 [96.8%] for observer 2 for the MRCP set). However, for the intrahepatic stones, the diagnostic accuracy (0.993) and the sensitivity (98.5%) of the combined interpretation were significantly higher than those of the MRCP set for the two observers (0.926 [83.8%] for observer 1 and 0.922 [85.3%] for observer 2) (p < 0.05). No significant difference was seen in the specificity of the two image sets for both the intrahepatic and the common duct stones.


CONCLUSIONS
Combining the axial T1-weighted image with MRCP is valuable for detecting intrahepatic stones.
Kim
Young Kon
YK
Department of Diagnostic Radioology, Chonbuk National University Medical School and Hospital, 634-18 Keumam dong, Jeonju, Chonbuk, South Korea. jmyr@dreamwiz.com
Kim
Chong Soo
CS
Lee
Jeong Min
JM
Ko
Seog Wan
SW
Chung
Gyung Ho
GH
Lee
Seung Ok
SO
Han
Young Min
YM
Lee
Sang Yong
SY
D000328:Adult; D000368:Aged; D049448:Cholangiopancreatography, Magnetic Resonance / Q000379:methods*; D005260:Female; D042882:Gallstones / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity