胆管胆石症診断における経静脈性ならびに経皮的胆道造影法の意義

Significance of Intravenous and Percutaneous Cholangiography for Diagnosing Choledocholithiasis

　近年，胆道疾患の診断法の進歩は著しく，PTC，ERCなどの直接胆道造影法や超音波検査，X線CTなどが用いられてきている．排泄性胆道造影法に加えて，これらの多彩な診断法の出現により，それぞれの診断法の適応が見直されてきている¹⁾．ところで，排泄性胆道造影法には経口法と経静脈法（IVC）とがある．前者は簡便に胆囊を造影しうるが，胆管の造影に難点があり，胆管病変の診断には専らIVCが用いられる．

　胆管胆石症の診断にも種々の検査法が用いられてきたが，現在でもIVCが診断の基本となっていることに変わりがない¹⁾．しかしながら，“IVCの造影能は劣っており，たとえ胆管が造影されても胆石像までは明瞭に写し出されることが少ない”という先入観もあって，直接胆道造影法に頼りがちな傾向がないとは言えない．直接造影はしばしば，疑問を差し挾む余地がないほどの完壁な情報を与えてくれるが，安全性や患者の負担などを考慮すれば，その適応は慎重でなければならないと考える．

　1. In order to evaluate intravenous cholangiography (IVC) in the diagnosis of choledocholithiasis, we examined 50 such cases as confirmed by endoscopic retrograde cholangiography. The bile duct was visualized by IVC in 43 cases (86%) and in 7 (14%) it was not visualized. In 32 cases (64%) the bile duct was well opacified. The common bile duct was dilated more than 8 mm in diameter in 88%. Gallstones, in the common bile duct were detected in 27 cases (54%), corresponding to about 63% of cases with visualized bile duct, and to 75% of well opacified cases. Stones larger than 10 mm in diameter were found in all such cases. Those of medium size ranging from 5 to 10 mm were found in 71%, and smaller stones less than 5 mm in diameter were found in 60%. The degree of bile duct dilation is naturally affected by the size of stones. While in cases with well visualized bile duct dilated more than 8 mm in diameter gallstones were found in 82%, they were seen in only 25% in cases with non-dilated common bile duct. Consequently, demonstration of gallstones was influenced by visualization of the bile duct, the size of gallstones and the width of the bile duct.

　2. Direct cholangiography such as percutaneous or endoscopic cholangiography is needed in cases with jaundice or if IVC fails to visualize the bile duct. Percutaneous transhepatic cholangiography is preferred in cases with stones in the common bile duct associated with obstructive jaundice, bacterial infection of the bile duct or intrahepatic gallstones. The entire picture of choledocholithiasis is made more distinct.