Usefulness of intraductal ultrasonography in gallbladder disease

This study was designed to compare intraductal ultrasonography of the gallbladder wall with histopathologic findings and to assess the clinical usefulness of this imaging method in gallbladder disease. Thirty-one gallbladder specimens were examined by intraductal ultrasonography retrospectively. The gallbladder is composed of three layers: an innermost hyperechoic layer, a middle hypoechoic layer, and an outermost hyperechoic layer. The second layer on ultrasonograms corresponds to the muscle layer plus the fibrous tissue of the superficial perimuscular connective tissue layer. In cases in which the thickness of the second layer was 500 μm or less, little fibrous tissue was seen and the second layer was approximately identical to the muscle layer on sonograms. Clinical study was performed on 22 gallbladders. The use of a guidewire through the papilla facilitated intraductal ultrasonographic examination. The intraductal sonographic probe could be inserted into the gallbladder fundus in 13 of 22 cases. In nine unsuccessful cases, technical difficulties were as follows: sharply angulated gallbladder (four cases), stenosis of the gallbladder (two cases), difficulty in transmitting power in the correct direction (three cases). With regard to the area visualized in 13 successful cases, in three cases the area visualized was 100%, in seven cases it was 75%, and three cases it was 50%. Intraductal ultrasonographic images could be obtained in 83.3% (10 of 12) of elevated lesions of the gallbladder. The indications for intraductal ultrasonography will be cases in which an abnormality was detected by transabdominal ultrasonography or other modalities in which the physician does not know whether or not to operate. In conclusion, we defined the intraductal sonographic images of gallbladder wall and clarified the clinical indications for use of this imaging method.