Ultrasound examination is the gold standard for evaluating gallbladder pathologies. Ultrasound is a safe, non-invasive, low-cost modality that provides images in real-time. Ultrasound provides an optimal image of the whole gallbladder. Examination of the gallbladder requires the patient to be fast 6-8 hours prior to the scan. The shape, wall thickness, regularity, and texture of the gallbladder wall and contents are evaluated. The gallbladder is a pear-shaped organ located between the right and left lobes of the liver. its primary function is to store bile which is a yellowish digestive enzyme produced by the liver. It measures 7 – 10 cm in length and 3cm in diameter when distended. It is divided into the fundus, body, and neck. The fundus is the most distal part of the gallbladder.
Gallbladder ultrasounds are used to evaluate the following medical conditions:
1. Gallstones: When bile is stored in the gallbladder, significant amounts of cholesterol, bile salts, or bilirubin can cause hardens into stone-like material, gallstones. Bile is stored in the gallbladder and secreted through bile ducts in order to aid in fat digestion. Risk factors include being a female in her forty’s, fair-haired, obese, diabetic, and pregnant. Rapid weight loss, fasting, cholesterol-lowering drugs, and age over 60 can increase the risk of having gallstones. Gallstones are varied in size and number. The majority of patients are asymptomatic, or they can present with abdominal right upper quadrant pain, nausea, vomiting, fever, chills, Jaundice, abdominal bloating, right shoulder pain, pain in the back between the shoulder blades. Ultrasound has high sensitivity in detecting gallstones.
2. Cholecystitis: Cholecystitis can be acute or chronic. Acute cholecystitis is the inflammation of the gallbladder, usually due to a gallstone obstructing the cystic duct. In 90% of the patients, it’s due to the presence of gallstones. However, it can also occur without gallstones and that is “acute a-calculous cholecystitis”. Symptoms include upper quadrant pain, fever, chills, nausea, and vomiting. Chronic cholecystitis is caused by repeated attacks of acute cholecystitis.
3. Choledocholithiasis: Choledocholithiasis is the presence of stones in the common bile duct (CBD). It develops in around 20% of patients that have stones in their gallbladder. Patients may be asymptomatic or present with pain and jaundice due to obstruction of bile from the liver.
4. Biliary Sludge: Gallbladder sludge develops when bile sits in the gallbladder for a long period of time. Mucus within the gallbladder combines with cholesterol and calcium creating a sludge. Patients usually experience right upper quadrant pain, and some can be asymptomatic.
5. Gallbladder Polyp: Polyps are abnormal growths that protrude from the lining inside the gallbladder. They are common, seen in around 8% of the population. Patients either present with pain like the pain of gallstones or they are asymptomatic. The majority of polyps are benign. However, larger polyps that measure more than 10 mm are most probably malignant.
6. Gallbladder Adenomyomatosis: Adenomyomatosis is a common benign gallbladder wall pathology that accounts for 40% of benign gallbladder lesions. It is caused by hyperplastic changes in the gallbladder wall causing thickening and formation of cystic spaces. Most patients are asymptomatic; however, it is commonly associated with gallstones.
7. Gallbladder cancer: Cancer of the gallbladder is rare and mainly occurs in older patients. In most patients, it is associated with gallstones and a history of cholecystitis. In the earlier stages, it might be asymptomatic, later on, patients present with right upper quadrant pain, a mass, and jaundice.
8. Porcelain gallbladder: This is a condition where the gallbladder wall is calcified. It is rare and the cause is unknown. However, it is commonly associated with gallstones and may represent a form of cholecystitis.