Ultrasonography (ultrasound): Ultrasound can identify about one half of gallbladder cancers. This test uses sound waves to produce images of internal organs. A transducer emits sound waves and detects the echoes as they bounce off the organs. The pattern of echoes is processed by a computer to produce images.
The echoes produced by most tumors differ from those of normal tissue. These patterns of echoes can help distinguish some types of benign and malignant tumors from one another. Relatively new techniques known as endoscopic or laparoscopic ultrasound combine ultrasound with the use of a thin, lighted tube that has an attached viewing device (an endoscope or laparoscope). The endoscope is inserted through the mouth and passed through the stomach and near the gallbladder area. The laparoscope is inserted through a surgical incision (cut) in the side of the patient's body. Both procedures allow the doctor to place the ultrasound transducer near the gallbladder to produce more detailed images than a standard ultrasound. If there is a tumor, the doctor may be able to tell if and how far it has invaded the gallbladder wall, which helps in planning for surgery. Ultrasound can often tell whether the cancer has invaded the liver.
Computed tomography (CT): The CT scan is an x-ray procedure that produces detailed cross-sectional images of your body. Instead of taking one picture, like a conventional x-ray, a CT scanner takes many pictures as it rotates around you while you are lying on a narrow platform. A computer then combines these pictures into an image of a slice of your body. The machine will take pictures of multiple slices of the part of your body that is being studied.
CT scans are often used to make the initial diagnosis of gallbladder cancer, and are helpful in staging the cancer (determining the extent of its spread).
CT scans can also show the organs near the gallbladder, as well as lymph nodes and distant organs where metastatic cancer (cancer that has spread) might be present. The CT scan can help to determine if surgery is a good treatment option.
This test can help tell if your cancer has spread into your liver or other organs. Often after the first set of pictures is taken you will receive an intravenous injection of a dye, a contrast agent to help outline structures in your body. A second set of pictures is then taken.
CT scans can also be used to guide a biopsy needle precisely into a suspected metastasis. For this procedure, called a CT-guided needle biopsy, the patient remains on the CT scanning table, while a radiologist advances a biopsy needle toward the location of the mass. A fine needle biopsy sample (tiny fragment of tissue) or a core needle biopsy sample (a thin cylinder of tissue about ยฝ inch long and less than 1/8 inch in diameter) is removed and examined under a microscope.
CT scans are more tedious than regular x-rays because they take longer and you need to lie still on a table while they are being done. But just like other computerized devices, they are getting faster and your stay might be pleasantly short. Also, you might feel a bit confined by the ring you lie within when the pictures are being taken.
You will need to put up with the intravenous (IV) line through which the contrast dye is injected. The injection can also cause some flushing. Some people are allergic and get hives or, rarely, more serious reactions like trouble breathing and low blood pressure. Please be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays. You may be asked to drink 1 to 2 pints of a solution of contrast material. This helps outline the intestine and allows the doctor to tell the difference between the intestine and any abnormal tissue that the CT scan may show.
Magnetic resonance imaging (MRI): MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of tissue and by certain diseases. A computer translates the pattern of radio waves given off by the tissues into a very detailed image of parts of the body. Not only does this produce cross-sectional slices of the body like a CT scanner, it can also produce slices that are parallel with the length of your body. A contrast material might be injected just as with CT scans, but is used less often. Although most doctors prefer CT scans as the first study to look at the gallbladder, an MRI scan may sometimes provide more detailed information, particularly if the doctors want to know whether the cancer is growing into nearby blood vessels.
MRI scans are particularly helpful in examining the brain and spinal cord. MRI scans are a little more uncomfortable than CT scans. First, they take longer, often up to an hour. Also, you have to be placed inside a tube, which is confining and can upset people with claustrophobia. The machine also makes a thumping noise that you may find disturbing. Many places provide headphones with music to block this out.
Angiography: Angiography is an x-ray procedure used to examine blood vessels. A small amount of contrast dye is injected into an artery to outline blood vessels before x-ray images are taken. The images allow the doctors to see if blood flow in a particular area is blocked or hindered by a tumor, and they can show any abnormal blood vessels in the area. Angiography can also show whether a gallbladder cancer has grown through the walls of certain blood vessels, or through the wall of the gallbladder. This information is mainly used to help surgeons decide whether a cancer can be removed and to help plan the operation. Digital subtraction angiography uses computers to produce more detailed images of blood vessels. Dynamic sequential CT scanning combines CT scanning and angiography.
Cholangiography: Cholangiography is similar to angiography. A small amount of contrast dye introduced into the gallbladder area allows a high-contrast image to be produced when that area is x-rayed. The x-ray images allow doctors to see if a tumor is in the gallbladder.
Endoscopic retrograde cholangiopancreatography (ERCP): In this procedure, a doctor passes a long, flexible tube down the patient's throat, through the esophagus and stomach, and into the common bile duct. A small amount of contrast dye helps outline the bile duct and pancreatic duct in x-ray images. The images can show narrowing or blockage of the bile duct or pancreatic duct and the doctor can also use the instrument to take cell samples. This procedure is used in gallbladder cancer mainly to help plan surgery.