Pregnant women with gallstone disease may require immediate endoscopic intervention because of potentially life-threatening cholangitis (infection in the bile ducts) or gallstone pancreatitis (inflammation of the pancreas).
The radiation exposure in endoscopic retrograde cholangiopancreatography (ERCP), which is used to treat these conditions, is a concern because fetal tissues are more susceptible to radiation injury. Researchers from Greece found that the radiation risks associated with ERCP procedures are not trivial and that accurate fetal dose estimation is now available regardless of patient body size, operating parameters, equipment used and gestational stage. The study appears in the April issue of GIE: Gastrointestinal Endoscopy , the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE).
Endoscopic retrograde cholangiopancreatography is a specialized technique used to study and treat problems of the ducts that drain the liver and pancreas. To reach the ducts, an endoscope is passed through the mouth, beyond the stomach and into the small intestine (duodenum). A thin tube is then inserted through the endoscope into the common bile duct and pancreatic duct connecting the liver and pancreas to the intestine. A contrast material (dye) is injected through the tube outlining those ducts as X-rays are taken. The X-rays can show narrowing or blockages in the ducts that may be due to a cancer, gallstones or other abnormalities. Radiation exposure is of obvious concern as developing fetal tissues are more susceptible to radiation injury.
During pregnancy, the most common indication for ERCP is treatment of choledocholithiasis (gallstones in the common bile duct). The occurrence of choledocholithiasis can reach up to 12 percent of the pregnant population and increases with gestational age. Given that symptomatic gallstone disease increases the risk of morbidity and mortality of both the fetus and mother, medical intervention often cannot be postponed pending delivery. Previous case series have demonstrated ERCP to be safe and effective during pregnancy.
Fetal doses are associated with exposure factors such as kilovolt peak (the peak voltage applied to an X-ray tube), tube filtration and the physique of the pregnant woman. Radiation dose is expressed as a milligray (mGy). A milligray is a unit of absorbed radiation equal to 0.001 gray. (A gray is the dose of one joule of energy absorbed per kilogram of matter, or 100 rad.) Because the gray is such a large unit, many radiation measurements are made in milligrays. Exposures from X-ray equipment are typically expressed in milligrays. National and international radiation protection authorities consider fetal radiation doses up to 1 mGy insignificant, while doses over 10 mGy are considered more relevant.
"Physicians should be able to estimate the fetal dose in all stages of gestation and inform any pregnant patient undergoing ERCP about the actual radiation risks to arrive at a prudent decision regarding the exposed fetus," said study lead author John Damilakis, MD, University of Crete, Greece. "The findings of this study show that fetal radiation risks associated with fluoroscopically (X-ray) guided ERCP performed on a pregnant patient cannot be disregarded. Nonradiation ERCP has been proposed as an alternative, especially for pregnant patients in an effort to decrease potential fetal risks. However, further studies are required to prove that the clinical efficiency of nonradiation ERCP remains at the same level with conventional fluoroscopically guided ERCP."
Patients and Methods