Percutaneous Transhepatic Cholangiography
In most cases, percutaneous transhepatic cholangiography (PTC) can be performed via the right midaxillary approach, though a subxiphoid approach is occasionally needed. Some patients (eg, those with a cholangiocarcinoma involving the hilum and central right and left hepatic ducts) may require bilateral access.
The skin-puncture site is selected by observing the right costophrenic sulcus during deep inspiration. The access point is generally in the midaxillary line in an intercostal space caudal to the costophrenic sulcus. The skin and subcutaneous tissues are anesthetized with local anesthetic.
A 21- or 22-gauge needle is then advanced into the liver under fluoroscopic guidance by aiming for the 12th thoracic vertebral body. After the inner stylet is withdrawn, contrast material is injected while the needle is retracted.
A study by Ignee et al suggested that extravascular contrast-enhanced ultrasonography (CEUS) may be a good alternative to fluoroscopy for guiding PTC and drainage. [12] Other studies have also supported the use of CEUS in PTC. [13]
Specific flow patterns of the contrast agent are noted. The vessels show opacification that disappears rapidly, whereas the bile ducts show slow opacification. The portal vein blood flows toward the periphery of the liver, filling the portal vein branches and sinusoids, whereas the hepatic vein blood flows toward the right atrium without filling its branches. The bile duct filling moves slowly toward the hilum into the extrahepatic duct. Occasionally, one may see filling of lymphatic channels, which are small in diameter and multiple.
After successful puncture of a bile duct, contrast medium is injected, and cholangiography is performed to delineate the biliary anatomy (see the image below).
Percutaneous cholangiography. Cholangiogram shows opacification of biliary system. Overfilling of biliary system should be avoided.
If the contrast medium flows freely through the bile duct into the duodenum, films are taken with additional injections of contrast medium in the multiple projections. If the bile duct is dilated secondary to biliary obstruction, an introducer is inserted for biliary decompression before a diagnostic cholangiogram and placement of a drainage catheter. Overdistention of an obstructed biliary system can cause bacteremia and sepsis.
If the needle enters a bile duct in a position unsuitable for subsequent catheterization, a second needle can be used to puncture the opacified ducts (see the image below). The left hepatic ducts are anterior in relation to the right lobe ducts and therefore may not fill with the patient in the supine position, because the contrast flows to the more posterior and dependent right ducts. If not already seen, the left hepatic ducts can be opacified by having the patient roll to the left.
Percutaneous cholangiography. Initial path of needle (superior) is at too acute an angle and would have caused difficulty in subsequent catheter placement for percutaneous biliary drainage if continued. Therefore, second puncture (inferior) is performed.
After the biliary system is delineated and images are obtained, the needle can be withdrawn if no further intervention is necessary.
The success rate for PTC is reported to be more than 95% in a dilated biliary system and 67-80% in a nondilated system. Additional needle passes increase the success rate.
Alternatives to PTC
Diagnostic PTC has largely been replaced by noninvasive diagnostic modalities such as magnetic resonance cholangiopancreatography (MRCP) and endoscopic US (EUS). With the advent of techniques such as EUS-guided biliary drainage that permits ERCP rendezvous or antegrade stenting to be performed, [14] the demand for PTC has been decreasing. However, PTC remains a very useful rescue therapy for biliary pathologies when other modalities fail.
Complications
Complications of PTC include the following:
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Sepsis (for which poor adherence to recommended antibiotic regimens may be a significant contributing factor [15] )
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Peritonitis
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Hemorrhage
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Pneumothorax
Pneumothorax is rare and is associated with a right-side approach. To minimize this risk, perform fluoroscopic examination of the right costophrenic sulcus during deep inspiration to evaluate diaphragmatic excursion, and choose a puncture site caudal to the sulcus.
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Percutaneous cholangiography. Cholangiogram shows opacification of biliary system. Overfilling of biliary system should be avoided.
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Percutaneous cholangiography. Initial path of needle (superior) is at too acute an angle and would have caused difficulty in subsequent catheter placement for percutaneous biliary drainage if continued. Therefore, second puncture (inferior) is performed.
