CT for right upper abdominal pain is commonly ordered to identify the cause. This is often referred to as right upper quadrant pain. The abdomen is divided into quadrants in medicine. Common entities that can cause pain in the right upper abdomen include the gallbladder, kidney abnormalities, bile duct obstructions, liver abnormalities, stomach problems, cancer amongst others. Not all causes of right upper abdominal pain have abnormalities on CT.
Perhaps one of the more common reasons for right upper abdominal pain are gallbladder abnormalities. Gallstones are sometimes seen on CT but ultrasound is better. When the gallbladder is inflamed this is called cholecystitis. On CT, this will often look like a big distended gallbladder having a thickened wall, stones and stranding of the fat. This means that the normally dark fat around the gallbladder will look hazy.
Kidney problems are also very common cause for right upper abdominal pain. Perhaps a passing kidney stone is the most common reason. This will often cause pain in the flank area. The kidney will look obstructed with a dilated collecting system. The stone causing the obstruction will be seen in the ureter. Infections of the kidneys called pyelonephritis will also be seen in some cases. This will cause areas of inflammation in and around the kidneys after administration of contrast through your vein.
Bile duct obstructions for various reasons will cause right upper quadrant pain. Most commonly this is seen with stones which lodge in the duct. The duct goes from the liver to the intestine. Pancreatitis or inflamed pancreas can also be caused by stones which pass into the duct. Cancer of the bile duct and pancreas will also cause the duct to get blocked. CT will often show the obstructing pancreas mass. Cases of bile duct cancer may need more invasive testing for diagnosis.
CT is not very good at diagnosing stomach problems. Ulcers, masses and inflammatory conditions of the stomach are often not seen on CT. An endoscopy done by a gastroenterologist is best for seeing the abnormalities directly. A perforated ulcer can be seen as air which escapes the stomach into the abdomen. An inflamed stomach called gastritis will result in a thickened wall. Masses are sometimes seen coming off the wall.
Right upper abdominal pain on CT has many causes, some of which are outlined above. Some causes of right upper abdominal pain have no CT abnormality. Others are not seen on CT and additional testing such as MRI or invasive tests are needed. Your physician will come to the most accurate diagnosis by combining a careful history, physical exam, labs, and imaging tests.