Interventional Radiology (IR), Frankford Hospitals
For diagnosing and treating liver, biliary, and pancreatic disorders , interventional radiology has become an important adjunct to endoscopy and surgery. This is particularly true for disorders of the biliary system . As the nexus of the of the biliary system , the common bile duct is an essential passage in the digestive system.
It consists of a tubelike structure that drains bile from the gallbladder and liver into the gastrointestinal tract at the
small intestine. Bile is a byproduct of protein metabolism that must be removed from the body.
The biliary duct can become blocked as a result of:
• disorders of the liver (including primary sclerosing cholangitis);
• long-standing anatomical obstructions;
• abnormal growths (including cancers in or around the duct, liver, pancreas, or surrounding areas);
• stone formation ;
• scarring in the duct;
• injury to the duct during surgery;
• and other causes.
| At its base, the common bile duct also drains digestive-enzyme fluids from the pancreas. Blockage at this juncture can cause pancreatitis (inflammation of the pancreas). Intervention radiologists can also use
the procedures described above to open or otherwise address this location as well. |
When such problems cause a back-up of bile, the condition is called cholestasis. Bile in this case will build up in the bloodstream, causing a
form of jaundice. Chronic compromise of bile duct function can cause life-threatening conditions such as infection and, over a longer period
of time, liver failure that can lead to the need for liver transplantation.
Interventional radiologists are key specialists in addressing problems in the bile duct. Their interventions can help to prevent pain, complications, and liver failure, and can help prepare patients for surgery. In evaluating or treating the condition, these specialists can use catheter procedures to accomplish these steps:
• biliary drainage. In this procedure, the interventionalist places a fine needle through the skin of the abdomen and into the liver, advancing
it into the bile duct. The team will use this access to place a drainage tube in the duct. This tube will drain bile to an external collection bag attached outside the body and placed against the skin or internally,
returning the bile to the small intestine. The tube may need to stay in place for weeks and may need to be replaced during this time, if it becomes plugged. Interventionalists may also use the procedure to help heal an injury to the duct or in preparation for surgery, such as removal
of a bile duct stone.
• stricture dilation. If the team should identify an area of narrowing or blockage in the duct, it may use the drainage access to insert a balloon
catheter (like those that it uses in angioplasty ) to correct this defect. The interventionalists will normally place a biliary drainage tube for a day or two prior to trying to dilate such strictures. The specialists can repeat these dilations as needed.
Percutaneous cholangiogram
Specialists employ many different diagnostic techniques for evaluating liver, biliary, and pancreatic conditions. Among these procedures, interventional radiologists provide a particularly important test: Percutaneous transhepatic cholangiography
(PTC), which allows the IR team to create an x-ray image of the liver, bile ducts, gallbladder, and gallbladder ducts.
For PTC, specialists insert a long, thin, flexible needle through a skin puncture in the abdomen in the area over the liver.
They advance the needle into the liver, inject a contrast dye, and then use fluoroscopy to locate the bile duct of the liver. At this location, the team injects additional contrast agent, permitting it to visualize
the rest of the biliary system with the x-ray imaging. PTC is especially useful in identifying and locating obstructions,
and thus differentiating between conditions that cause such symptoms as jaundice and pancreatitis. In some cases, these conditions
are caused by blockages and in some cases not. PTC is also important for evaluating the success of procedures such as stricture
dilation, stenting, and stone removal in the biliary duct. In addition, PTC can aid endoscopists seeking to use ERCP. If
these specialists cannot find access to the biliary tree, interventionalists can use the PTC technique to place a guide wire
that demonstrates the opening of the biliary tract by protruding past the base of the common bile duct and into the small
intestine. The wire serves as a marker for gastroenterologists in placing an endoscope into the common bile duct from the
intestine. |
• stent placement. The interventional team can also use stent placement to maintain the opening of the biliary duct. Normally,
the team will leave a biliary drainage tube in place for several weeks, across a narrowed area, as a kind of temporary stent. After this period, if the duct would revert to inadequate bile flow without the drainage tube, the specialists may attempt
one or more stricture dilations. Should these steps prove inadequate to maintain the duct opening, the team may place a stent, in the form of a tiny metal-mesh
tube matched to the length of the stricture, across the narrowed site. The stent preserves the opening of the duct and thus permits bile flow. (Interventionalists may also use this approach to maintain the competency of a bile duct that has a hole in it.) Several stents may be used together. The stents must be removed after several months but may be replaced with new stents as long as the patient requires relief
from biliary obstruction.
• tissue sampling. The interventional team can also use the
access created by the needle procedure or the drainage tube placement to take a sample of tissue (biopsy) or fluid from the bile system for evaluation in the laboratory.
• stone removal. Sometimes, despite the best surgical or endoscopic efforts, nodules or other calcifications from the bile system may be left
behind in the body and require subsequent removal. These retained stones are a common problem.
For example, surgically inaccessible stones in the common bile duct are not unusual. One solution is for the interventional radiologist to remove them via the access provided by a drainage tube placed several
weeks earlier. Once the opening provided by this tube has been well established, the interventionalist will insert a guidewire through the
tube, remove the tube, pass a sheath over the guidewire, and advance a small snare or basket device
through the sheath to acquire and draw out the stones. Other possible interventional steps include passing the stone into the small intestine or breaking up the stone for easier
retrieval.
Sometimes stones may be inadvertently left behind in the abdominal cavity, after a patient has undergone gallbladder removal. These stones can cause abscesses. The interventional team can retrieve these stones, or even, rarely, stones within the appendix, with percutaneous, catheter
techniques.
Endoscopic specialists in gastroenterology also provide a key approach to biliary conditions, using endoscopic retrograde cholangiopancreatography (ERCP) techniques. Sometimes they collaborate with intervention radiologists to combine this approach with the techniques described above.
