Objective—To evaluate the usefulness of serum biochemical
variables and scintigraphic study results for
differentiating between dogs and cats with complete
extrahepatic biliary obstruction (EHO) and those with
partial EHO or patent bile ducts.
Study Design—Retrospective case series.
Animals—17 dogs and 1 cat.
Procedure—Animals that underwent hepatobiliary
scintigraphy and had either surgical or postmortem
confirmation of the degree of bile duct patency were
included. Scintigraphic images were evaluated and biliary
tracts were classified as patent, partially obstructed
but patent, or obstructed. Surgery or postmortem
examination was considered the gold standard for
diagnosis, and compared with those findings, sensitivity
and specificity of scintigraphy were calculated.
Results—With absence of radioactivity in the intestinal
tract as the diagnostic criterion for EHO, the sensitivity
and specificity of scintigraphic diagnosis were
both 83% when final images were acquired at 19 to
24 hours, compared with 100% and 33%, respectively,
when 180 minutes was used as the cutoff time.
Animals with partial biliary obstruction had less
intestinal radioactivity that arrived later than that
observed in animals with patent biliary tracts.
Conclusions and Clinical Relevance—Animals in
which intestinal radioactivity has not been observed after
the standard 3 to 4 hours should undergo additional
scintigraphic imaging. Findings in animals with partial biliary
obstruction include delayed arrival of radioactivity
and less radioactivity in the intestine. Distinguishing
between complete and partial biliary tract obstruction is
important because animals with partial obstruction may
respond favorably to medical management and should
not be given an erroneous diagnosis of complete
obstruction. (J Am Vet Med Assoc 2005;227:1618–1624)
Case Description—A 13-year-old neutered female Keeshond-cross was evaluated because of a history of melena, anemia, hematemesis, vomiting, and high serum liver enzyme activities over a 1.5-year period.
Clinical Findings—Abdominal ultrasonography revealed a hyperechoic mass in the gallbladder. In the gallbladder mass itself, a distinct linear blood flow pattern was detected by use of color flow Doppler ultrasonography.
Treatment and Outcome—A cholecystectomy was performed, and clinical signs resolved. Samples of the mass were examined histologically and immunohistochemically, and findings supported a diagnosis of neuroendocrine tumor of the gallbladder.
Clinical Relevance—Tumors of the biliary tree are a potential source of blood loss into the gastrointestinal tract. Color flow Doppler ultrasonography in conjunction with conventional grayscale ultrasonography may be useful in evaluation of the gallbladder in dogs. When echogenic material is detected in the gallbladder, it is important to evaluate the region for blood flow.