Parasites and Biliary stones

Hepatolithiasis ٨٩
of different liver lobes. Sometimes the pigment stones may be difficult to
identify because of a CT density similar to that of the scarred or damaged
liver. CT provides a good preoperative assessment of the disease and may
help to localize obstructed segmental ducts not filled or visualized by
direct cholangiography. Technetium-labelled HIDA scanning serves to
evaluate the function of the underlying liver tissue associated with ductal
stones. A delay in the excretion of the isotope occurs in the affected
segments secondary to biliary obstruction and stasis, with subsequent
pooling of the isotope in the affected bile ducts (Pavone et al., 1996).
Endoscopic retrograde cholangiopancreatography (ERCP) and
percutaneous transhepatic cholangiography (PTC) are the two major
modalities for direct cholangiography. They serve to define the extent of
ductal involvement, especially ductal stricture or obstruction. PTC is
indicated to define ductal anatomy and the extent of disease, especially in
patients who have undergone prior biliary-enteric anastomosis or when
ERCP fails.Recent developments in non-invasive imaging include
magnetic resonance cholangiopancreatography (MRCP). MRCP produces
high-quality images without the injection of contrast agents, and the
sensitivity in defining the stones and strictures is similar to that of
conventional direct cholangiography (Liessi et al., 1996). MRCP is less
operator dependent and is easily reproducible. It provides additional
information on adjacent soft tissue not obtained from ERCP (Barish et
al., 1996). The major limitation of MRCP for the evaluation of biliary
disease is that it cannot offer therapeutic options (Outwater and
Gordon, 1994 and McDermott and Nelson, 1995).
Treatment:
Stones in the intrahepatic biliary tree offer especially difficult
treatment challenges, especially if the bile ducts are abnormal (stricture or