Intraductal ultrasonography for evaluating the patency of biliary metallic stents: correlation with cholangioscopic findings.
BACKGROUND
This is the first study to correlate intraductal ultrasonography (IDUS) with cholangioscopy in evaluating the patency of biliary metallic stents.


METHODS
The findings of IDUS (probe 2.0 mm in diameter and 20-MHz frequency) through a percutaneous transhepatic (n = 24) or transpapillary (n = 2) approach were retrospectively reviewed without other information. Criteria for IDUS are as follows: type 1, the inside of the stent is free; type 2, the inner edge is smooth; type 3, the inner edge is irregular; type 4, the inside of the stent is totally occupied; type 5, the solid echo is connected to the outside mass; type 2+D, a hypoechoic line is seen between the bile duct wall and the inside solid component and the inner edge of the bile duct wall is smooth; type 3+D, an irregular hypoechoic line is seen between the bile duct wall and the inside solid component.


RESULTS
In the control group (n = 11), IDUS showed type 1 (n = 9) or type 2 (n = 2). In the occluded group (n = 15), when IDUS showed type 3 or 5, the patients (n = 5) required additional stents (n = 3), microwave coagulation of the tumor (n = 1), or transient external drainage (n = 1). When IDUS showed type 4 (n = 5), after washing, the findings changed to type 2+D (n = 4). When IDUS after washing showed a smooth inner edge (type 2+D), the patients were treated without additional stents more frequently than the other groups (eight of nine vs. two of six), a significant distinction (p < 0.05).


CONCLUSIONS
IDUS is useful in assessing the patency of metallic stents. When the inside of the stent is totally occupied, however, examination after washing is necessary.
Tamada
K
K
Department of Gastroenterology, Jichi Medical School, Yakushiji, Tochigi 329-0498, Japan.
Tomiyama
T
T
Ohashi
A
A
Wada
S
S
Satoh
Y
Y
Higashizawa
T
T
Gotoh
Y
Y
Ido
K
K
Sugano
K
K
D000368:Aged; D000369:Aged, 80 and over; D001652:Bile Ducts / Q000000981:diagnostic imaging* / Q000473:pathology; D016145:Endoscopy, Digestive System; D005260:Female; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D012189:Retrospective Studies; D015607:Stents; D014463:Ultrasonography
D008670:Metals