K. Tamada et al., Utility and limitations of intraductal ultrasonography in distinguishing longitudinal cancer extension along the bile duct from inflammatory wall thickening, ABDOM IMAG, 26(6), 2001, pp. 623-631
Background: We wanted to distinguish wall thickening caused by cancer exten
sion from that caused by inflammation after placing a biliary catheter on i
ntraductal ultrasonography (IDUS).
Methods: We studied 51 patients with biliary tract malignancies who had und
ergone placement of biliary drainage catheters before IDUS. IDUS was perfor
med from a transhepatic (n = 34) or transpapillary (n = 17) route with a th
in-caliber ultrasonic probe (2.0 mm in diameter, 20-MHz frequency). At the
hepatic side of the tumor, the thickness, asymmetry, outer margin, inner ma
rgin, and internal echoes of the bile duct wall were reviewed prospectively
and correlated with the histologic findings of the surgically resected spe
cimens in all cases.
Results: When IDUS showed wall thickening in a semi-circular fashion, notch
ed outer margin, rigid inner margin, papillary inner margin, and heterogene
ous internal echoes, each finding had a positive predictive value for diagn
osing cancer extension (100%, 100%, 83%, 100%, and 90%, respectively). When
these factors were used as the diagnostic criteria of cancer extension, ID
US accurately demonstrated suitable surgical margins in 76% of all patients
and 71% of patients with bile duct carcinoma.
Conclusion: Wall thickening in a semicircular fashion, notched outer margin
, rigid or papillary inner margin, and heterogeneous internal echoes are sp
ecific for cancer extension. However, surgical margins can be inaccurately
assessed in some patients.