Analysis Of Extrahepatic Bile Duct Stones Missed At MSCT And MRI

Part one Extrahepatic Bile Duct Stones Missed at MSCT:Features and CountermeasuresObjective: To investigate the features of missed extrahepatic bile duct stones by multi-slice computed tomography(MSCT) retrospectively, and analyze the causes of missed and misdiagnosis.Materials and Methods: 43 patients with extrahepatic bile duct stones that were confirmed by ERCP underwent both MSCT and MRI. The results were cotrol with ERCP.Results: The stones of density less than 40 HU and silt stones were all missed on MSCT. The missed rates is 100%, and obviously higher than other two groups(?~2=58.973,P<0.001).In the density of 40~60HU stones group, missed and misdiagnosis rates of the long diameter less than 0.5cm, 0.5~1.0 cm and more than 1.0cm stones were 100%, 40% and 11% respectively. In this group, the missed rate of the long diameter less than 0.5cm stones is obviously higher than other two diameter groups(?~2=11.441,P=0.003).In the density of more than 60 HU stones group, missed and misdiagnosis rates of the long diameter less than 0.5cm, 0.5~1.0 cm and more than 1.0cm stones were 25%, 20% and 14% respectively. In this group, missed and misdiagnosis rates are no difference in different diameter stones(?~2=4.273,P=0.403).In the density of 40~60HU stones group, missed and misdiagnosis rates of patients with and without choledochectasia were 60%, 100% respectively. There is no difference between the groups(?~2=1.200,P=0.549). In the density of more than 60 HU stones group, missed and misdiagnosis rates of patients with and without choledochectasia were 22%, 50% respectively. There is no difference between the groups(?~2=2.568,P=0.277).Conclusion: The missed and misdiagnosis of extrahepatic bile duct stones were concluded by multiple factors: density, size, location, and choledochectasia. Part two Extrahepatic Bile Duct Stones Missed at 3.0T MRI:Features and CountermeasuresObjective: To investigate the features of missed extrahepatic bile duct stones by 3.0T MRI(MRCP) retrospectively, and analyze the missed causes.Materials and Methods: 43 patients with extrahepatic bile duct stones confirmed by ERCP underwent MRI(MRCP), the results were cotrol with ERCP.Results: The missed diagnosis rate of MRCP in the diagnosis of extrahepatic bile duct stones was 30.23%. This study defined stones with long diameters >5 mm as large stones, and ?5 mm as small stones, The remaining stones similar to fluid were classified as silt stones. The missed diagnosis rate of silt stones, small stones and large stones were 100%, 30.77% and 12.5%, respectively. There are obviously differences in the three groups(?~2=15.938,P=0.0001). With increase of long diameter of extrahepatic bile duct stones, the missed diagnosis rate of MRCP declined. The missed diagnosis rate of patients with and without choledochectasia were 20%, 53.85%, respectively. There is obviously difference in the two groups(?~2=4.926,P=0.026).The missed diagnosis rate of patients with choledochectasia is higher than in patients without choledochectasia.Conclusion: The missed diagnosis of MRCP in extrahepatic bile duct stones were concluded by multiple factors: size, location, and choledochectasia.