ERCP (Endoscopic Retrograde Cholangio pancreatography)
Anatomy Demonstrated
Endoscopic refers to the use of an instrument called an endoscope - a thin, flexible tube with a tiny video camera and light on the end. The endoscope is used by a highly trained subspecialist, the gastroenterologist, to diagnose and treat various problems of the GI tract. The GI tract includes the stomach, intestine, and other parts of the body that are connected to the intestine, such as the liver, pancreas, and gallbladder.
Retrograde refers to the direction in which the endoscope is used to inject a liquid enabling X-rays to be taken of the parts of the GI tract called the bile duct system and pancreas.
The process of taking these X-rays is known as cholangiopancreatography. Cholangio refers to the bile duct system, pancrea to the pancreas.
Indications for imaging
Retrograde refers to the direction in which the endoscope is used to inject a liquid enabling X-rays to be taken of the parts of the GI tract called the bile duct system and pancreas.
The process of taking these X-rays is known as cholangiopancreatography. Cholangio refers to the bile duct system, pancrea to the pancreas.
Indications for imaging
- Gallstones, which are trapped in the main bile duct
- Blockage of the bile duct
- Yellow jaundice, which turns the skin yellow and the urine dark
- Undiagnosed upper-abdominal pain
- Cancer of the bile ducts or pancreas
- Pancreatitis (inflammation of the pancreas) The main symptoms of pancreatitis are acute, severe pain in the upper abdomen, frequently accompanied by vomiting and fever. The abdomen is tender, and the patient feels and looks ill. The diagnosis is made by measuring the blood pancreas enzymes which are elevated. A sound wave test (ultrasound) or abdominal CT exam often shows an enlarged pancreas. The condition is treated by resting the pancreas while the tissues heal. This is accomplished through bowel rest, hospitalization, intravenous feeding and, pain medications.
When pancreatitis is caused by gallstones, it is necessary to remove the gallbladder. This is usually done after the acute pancreatitis has resolved. At times, an ERCP (Endoscopic Retrograde CholangioPancreatography) test is recommended. This involves passing a flexible tube through the mouth and down to the small intestine. A small catheter is then inserted into the bile duct to see if any stones are present. If so, they are then removed with the scope.
Patient Preparation
When preparing a patient for a gastrointestinal x-ray examination, every consideration should be given to informing the patient of the examination's purpose, the technique and duration of the procedure, and any anticipated discomfort or risk. This prepares the patient psychologically for the procedure and is of equal importance for the preparation of the patient's alimentary tract for receiving the contrast material. Optimum evaluations of the esophagus, stomach, small intestine, and colon are done only when these organs are empty and clean. This is the objective of the detailed and at times arduous preparation instructions which are given to patients prior to these examinations. These instructions should be thoroughly familiar to the referring physician and understood by the patient.
Patients should ingest no solids for at least 6-7 hours and no liquids for at least four hours prior to the procedure. If a gastric emptying problem is suspected, a longer period of fasting may be needed. If circumstances do not permit an adequate fast, lavage of the stomach through a large bore tube can adequately remove stomach contents. For some procedures, topical pharyngeal anesthesia alone is sufficient, especially when the endoscopy is performed with a small diameter endoscope. For prolonged examinations, those in children, or in patients with a high degree of anxiety, rapid onset sedatives and/or analgesics are often necessary. Anticholinergics (e.g., atropine) have been given to decrease saliva, gastric secretions and motility, and perhaps reduce the likelihood of vasovagal reactions; however, controlled studies of their value as endoscopic premedication do not support their routine use. For procedures in which paresis of gastroduodenal motility is necessary, parenteral glucagon may be useful
The patient is prepared as for upper gastrointestinal endoscopy. Because of the longer duration and potential discomfort of the procedure an intravenous line is desirable. If cannulation is delayed, or therapeutic maneuvers prove necessary, repeated doses of sedatives or analgesics may be needed.Careful monitoring of vital signs and level of consciousness is essential throughout and immediately after the examination. Glucagon, with or without anticholinergics administered intravenously will reduce duodenal motility. Use of iodinated contrast agents for ERCP appears to be safe in individuals with a history of systemic reactions to intravascular contrast agents.
When an obstructed duct is suspected, most endoscopists administer antibiotics intravenously prior to the ERCP, and continue antibiotics for 24-48 hours if contrast has been instilled into an obstructed system. The benefits of adding antibiotics to contrast solution has not been proven. Depending on the indication for the ERCP, surgical support should be available anticipating possible abdominal surgery
Basic Proceedure
The throat is anesthetized with a spray or solution, and the patient is usually mildly sedated. The endoscope is then gently inserted into the upper esophagus. The patient breathes easily throughout the exam, with gagging rarely occurring. A thin tube is inserted through the endoscope to the main bile duct entering the duodenum. Contrast media is then injected into this bile duct and/or the pancreatic duct and x-ray films are taken. The patient lies on his or her left side and then turns onto the stomach to allow complete visualization of the ducts. If a gallstone is found, steps may be taken to remove it. If the duct has become narrowed, an incision can be made using electrocautery (electrical heat) to relieve the blockage. Additionally, it is possible to widen narrowed ducts and to place small tubing, called stents, in these areas to keep them open. The exam takes from 20 to 40 minutes, after which the patient is taken to the recovery area
When preparing a patient for a gastrointestinal x-ray examination, every consideration should be given to informing the patient of the examination's purpose, the technique and duration of the procedure, and any anticipated discomfort or risk. This prepares the patient psychologically for the procedure and is of equal importance for the preparation of the patient's alimentary tract for receiving the contrast material. Optimum evaluations of the esophagus, stomach, small intestine, and colon are done only when these organs are empty and clean. This is the objective of the detailed and at times arduous preparation instructions which are given to patients prior to these examinations. These instructions should be thoroughly familiar to the referring physician and understood by the patient.
Patients should ingest no solids for at least 6-7 hours and no liquids for at least four hours prior to the procedure. If a gastric emptying problem is suspected, a longer period of fasting may be needed. If circumstances do not permit an adequate fast, lavage of the stomach through a large bore tube can adequately remove stomach contents. For some procedures, topical pharyngeal anesthesia alone is sufficient, especially when the endoscopy is performed with a small diameter endoscope. For prolonged examinations, those in children, or in patients with a high degree of anxiety, rapid onset sedatives and/or analgesics are often necessary. Anticholinergics (e.g., atropine) have been given to decrease saliva, gastric secretions and motility, and perhaps reduce the likelihood of vasovagal reactions; however, controlled studies of their value as endoscopic premedication do not support their routine use. For procedures in which paresis of gastroduodenal motility is necessary, parenteral glucagon may be useful
The patient is prepared as for upper gastrointestinal endoscopy. Because of the longer duration and potential discomfort of the procedure an intravenous line is desirable. If cannulation is delayed, or therapeutic maneuvers prove necessary, repeated doses of sedatives or analgesics may be needed.Careful monitoring of vital signs and level of consciousness is essential throughout and immediately after the examination. Glucagon, with or without anticholinergics administered intravenously will reduce duodenal motility. Use of iodinated contrast agents for ERCP appears to be safe in individuals with a history of systemic reactions to intravascular contrast agents.
When an obstructed duct is suspected, most endoscopists administer antibiotics intravenously prior to the ERCP, and continue antibiotics for 24-48 hours if contrast has been instilled into an obstructed system. The benefits of adding antibiotics to contrast solution has not been proven. Depending on the indication for the ERCP, surgical support should be available anticipating possible abdominal surgery
Basic Proceedure
The throat is anesthetized with a spray or solution, and the patient is usually mildly sedated. The endoscope is then gently inserted into the upper esophagus. The patient breathes easily throughout the exam, with gagging rarely occurring. A thin tube is inserted through the endoscope to the main bile duct entering the duodenum. Contrast media is then injected into this bile duct and/or the pancreatic duct and x-ray films are taken. The patient lies on his or her left side and then turns onto the stomach to allow complete visualization of the ducts. If a gallstone is found, steps may be taken to remove it. If the duct has become narrowed, an incision can be made using electrocautery (electrical heat) to relieve the blockage. Additionally, it is possible to widen narrowed ducts and to place small tubing, called stents, in these areas to keep them open. The exam takes from 20 to 40 minutes, after which the patient is taken to the recovery area
Side Effects and Risks
A temporary, mild sore throat sometimes occurs after the exam. Serious risks with ERCP, however, are uncommon. One such risk is excessive bleeding, especially when electrocautery is used to open a blocked duct. In rare instances, a perforation or tear in the intestinal wall can occur. Inflammation of the pancreas also can develop. These complications may require hospitalization and, rarely, surgery.
There is also a small risk of an allergic reaction to the dye, which contains iodine. Rarely, drugs used to relax the ampulla of Vater can have side effects such as nausea, dry mouth, flushing, urinary retention, rapid heart rate (sinus or supraventricular tachycardia), or a drop in blood pressure
Due to the mild sedation, the patient should not drive or operate machinery for six hours following the exam. For this reason, a driver should accompany the patient to the exam
Contrast Media
Typical - 20 mls non-ionic/low-osmolality 200 mg/ml contrast media
Radiation protection
"28 Day Rule"
Direct lead rubber waist level protection
General Fluoroscopic radiation protection / dose reduction methods
Exposure Factors
Kv mAS FFD (cm) Grid Focus AEC Cassette
85 20 100 Yes Broad Yes 18 x 24 cm
Image
ID and anatomical markers must be present and correct in the appropriate area of the film.
Optimal exposure should penetrate contrast should be low enough to visualise fully the bone and soft tissue structures.
A temporary, mild sore throat sometimes occurs after the exam. Serious risks with ERCP, however, are uncommon. One such risk is excessive bleeding, especially when electrocautery is used to open a blocked duct. In rare instances, a perforation or tear in the intestinal wall can occur. Inflammation of the pancreas also can develop. These complications may require hospitalization and, rarely, surgery.
There is also a small risk of an allergic reaction to the dye, which contains iodine. Rarely, drugs used to relax the ampulla of Vater can have side effects such as nausea, dry mouth, flushing, urinary retention, rapid heart rate (sinus or supraventricular tachycardia), or a drop in blood pressure
Due to the mild sedation, the patient should not drive or operate machinery for six hours following the exam. For this reason, a driver should accompany the patient to the exam
Contrast Media
Typical - 20 mls non-ionic/low-osmolality 200 mg/ml contrast media
Radiation protection
"28 Day Rule"
Direct lead rubber waist level protection
General Fluoroscopic radiation protection / dose reduction methods
Exposure Factors
Kv mAS FFD (cm) Grid Focus AEC Cassette
85 20 100 Yes Broad Yes 18 x 24 cm
Image
ID and anatomical markers must be present and correct in the appropriate area of the film.
Optimal exposure should penetrate contrast should be low enough to visualise fully the bone and soft tissue structures.
Alternative Imaging
Alternative tests to ERCP include certain types of x-rays (CAT scan, CT) and sonography (ultrasound) to visualize the pancreas and bile ducts. In addition, dye can be injected into the bile ducts by placing a needle through the skin and into the liver. Small tubing can then be threaded into the bile ducts. Study of the blood also can provide some indirect information about the ducts and pancreas
Magnetic resonance cholangiopancreatography (MRCP) was first reported in 1991 by Wallner. Since then it has become a well recognised investigation in the non-invasive work-up of patients with pancreaticobiliary disease including calculus disease, chronic pancreatitis, biliary strictures, sclerosing cholangitis and congenital disorders. It is particularly useful in preoperative mapping of the ductal systems or where previous surgery may have altered the anatomy e.g. laparoscopic cholecystectomy.
Magnetic resonance cholangiopancreatography (MRCP) was first reported in 1991 by Wallner. Since then it has become a well recognised investigation in the non-invasive work-up of patients with pancreaticobiliary disease including calculus disease, chronic pancreatitis, biliary strictures, sclerosing cholangitis and congenital disorders. It is particularly useful in preoperative mapping of the ductal systems or where previous surgery may have altered the anatomy e.g. laparoscopic cholecystectomy.
MRCP is made possible by stationary fluid in the ducts producing a high intensity signal. This can then be recognised separately from the surrounding structures. Once the area in question has been defined a series of thin slices 2 - 5mm thick are taken and computer processing is applied to construct the images. The images can be either cross-sectional (tomographic), to visualise the bile ducts as well as surrounding structures or projectional (cholangiographic) which produces images similar to a cholangiogram. A contrast can be used to produce finer detail of the smaller ducts but this is not routine. Furthermore an MR examination of the liver and pancreas can be incorporated into the examination but again this is not routine and it adds a considerable amount of time onto what is otherwise a very quick examination.
There are many advantages of MRCP compared with previous imaging techniques. It does not require the use of contrast so avoiding the possibility of a reaction. In fact safety is comparable to ultrasound providing the few contraindications are observed and since no radiation is used. No special patient preparation is required and the procedure is very rapid to perform.
When compared to ERCP or PTC the accuracy is very similar. MRCP has a sensitivity and specificity of 91% and 98% respectively for choledocholithiasis . Its accuracy for benign and malignant obstruction is 90%. Furthermore it does not carry the 5 - 30% failure rate associated with ERCP . It is also spares the morbidity (1-7%) and mortality (0.2-1%) of ERCP and is twice as cost effective .
The disadvantage is that it is solely a diagnostic test. For this reason it should not be used in choledocholithiasis when there is a high likelihood of a CBD stone. In this situation ERCP would be indicated since endobiliary therapy can also be carried out. MRCP is not the initial investigation of choice in cholecystitis as ultrasound is just as accurate and much more cost effective.
MRCP has many benefits when compared to other methods of biliary imaging and will be used increasingly as MR technology becomes more available.
Alternative tests to ERCP include certain types of x-rays (CAT scan, CT) and sonography (ultrasound) to visualize the pancreas and bile ducts. In addition, dye can be injected into the bile ducts by placing a needle through the skin and into the liver. Small tubing can then be threaded into the bile ducts. Study of the blood also can provide some indirect information about the ducts and pancreas
Magnetic resonance cholangiopancreatography (MRCP) was first reported in 1991 by Wallner. Since then it has become a well recognised investigation in the non-invasive work-up of patients with pancreaticobiliary disease including calculus disease, chronic pancreatitis, biliary strictures, sclerosing cholangitis and congenital disorders. It is particularly useful in preoperative mapping of the ductal systems or where previous surgery may have altered the anatomy e.g. laparoscopic cholecystectomy.
Magnetic resonance cholangiopancreatography (MRCP) was first reported in 1991 by Wallner. Since then it has become a well recognised investigation in the non-invasive work-up of patients with pancreaticobiliary disease including calculus disease, chronic pancreatitis, biliary strictures, sclerosing cholangitis and congenital disorders. It is particularly useful in preoperative mapping of the ductal systems or where previous surgery may have altered the anatomy e.g. laparoscopic cholecystectomy.
MRCP is made possible by stationary fluid in the ducts producing a high intensity signal. This can then be recognised separately from the surrounding structures. Once the area in question has been defined a series of thin slices 2 - 5mm thick are taken and computer processing is applied to construct the images. The images can be either cross-sectional (tomographic), to visualise the bile ducts as well as surrounding structures or projectional (cholangiographic) which produces images similar to a cholangiogram. A contrast can be used to produce finer detail of the smaller ducts but this is not routine. Furthermore an MR examination of the liver and pancreas can be incorporated into the examination but again this is not routine and it adds a considerable amount of time onto what is otherwise a very quick examination.
There are many advantages of MRCP compared with previous imaging techniques. It does not require the use of contrast so avoiding the possibility of a reaction. In fact safety is comparable to ultrasound providing the few contraindications are observed and since no radiation is used. No special patient preparation is required and the procedure is very rapid to perform.
When compared to ERCP or PTC the accuracy is very similar. MRCP has a sensitivity and specificity of 91% and 98% respectively for choledocholithiasis . Its accuracy for benign and malignant obstruction is 90%. Furthermore it does not carry the 5 - 30% failure rate associated with ERCP . It is also spares the morbidity (1-7%) and mortality (0.2-1%) of ERCP and is twice as cost effective .
The disadvantage is that it is solely a diagnostic test. For this reason it should not be used in choledocholithiasis when there is a high likelihood of a CBD stone. In this situation ERCP would be indicated since endobiliary therapy can also be carried out. MRCP is not the initial investigation of choice in cholecystitis as ultrasound is just as accurate and much more cost effective.
MRCP has many benefits when compared to other methods of biliary imaging and will be used increasingly as MR technology becomes more available.