![]() ![]() Percutaneous cholecystostomy can be used as a temporizing measure in critically ill patients who are too sick to proceed to immediate surgery and cholecystectomy. There is an increasing role for interventional radiology (IR) in gallstone-related diseases. This is actually superior to ultrasound however, this technique is more expensive and time consuming and also confers a radiation dose to the patient and staff and thus is generally not a first-line investigation (Fig. Cholescintigraphy for acute cholecystitis has a sensitivity of 97% and a specificity of 94%. If the gallbladder is not visualised, morphine analogues can be given to induce sphincter of Oddi contraction and aid gallbladder filling. In cases of cholecystitis or gallbladder obstruction due to an impacted stone in the cystic duct, the gallbladder will not be visualised as the radioactive will not accumulate within the gallbladder. A normal gallbladder will be well delineated as it fills with radioactive bile. ![]() The patient is typically imaged at 1 h and at 4 h post-administration of radioisotope. Technicium-99 labeled mebrofenin is administered and taken up by bile producing cells and subsequently excreted into the biliary system. Nuclear medicine imaging with scintigraphy and with SPECT/CT can be used to dynamically assess the gallbladder. Calcification of gallstones occurs with increased calcium in bile (Fig. The classical radiographic appearance is the “Mercedes Benz sign” which is an outer radio-opaque rim with a radiolucent centre which is caused by calcification of the gallstone rim and gas fissuring within the gallstone. Plain radiography is limited in the diagnosis of gallstones as only 15–20% of gallstones are radio-opaque on X-ray. This requires further work up with alternative imaging. Occasionally, a stone can be seen within the biliary system however, often the presence of a CBD stone can be inferred from visualised proximal biliary dilatation and clinical presentation with painful jaundice or an obstructive pattern on liver function tests. The major limitation of ultrasound in the imaging of gallstone-related disease is the frequent inability to assess the distal common bile duct (CBD) due to overlying bowel gas. Sonographic Murphy’s sign is where the patient reports maximal pain as the sonographer presses over the fundus of the distended gallbladder with the ultrasound probe (and differs to clinical Murphy’s sign). ![]() The main risk factors for gallstone formation are outlined in Table 1, and the factors protective against gallstones are outlined in Table 2.Īnother principle advantage of ultrasound over other imaging techniques in the investigation of acute cholecystitis is the ability to evaluate for a sonographic Murphy’s sign, which can be a reliable indicator of acute cholecystitis with a high sensitivity. For this reason, it is suggested that once symptoms present, the patient should be offered a cholecystectomy. The risk for gallstone-related pathology is also related to the number and size of stones with numerous larger stones more likely to cause symptoms. In a patient that has suffered a symptomatic manifestation of gallstones, the incidence of a further manifestation over their lifetime is approximately 3% per year. The symptomatic manifestations of gallstones are variable and range from mild symptoms such as biliary colic to severe acute presentations such as pancreatitis, which can be associated with significant morbidity and mortality. The vast majority of gallstones are asymptomatic and require no follow-up however, approximately 10–15% of gallstones will become symptomatic over a period of 10–15 years of follow-up. In the USA, 8.6% of Caucasian men and 16.6% of women have gallstones. ![]() The incidence of gallstones is increasing in Western populations as obesity levels rise. The size and number of gallstones is variable with some patients forming multiple small gallstones and others forming single or few large stones. Gallstones are solid rounded particles composed of a combination of cholesterol and bilirubin that form within the gallbladder and within the biliary system. ![]()
0 Comments
Leave a Reply. |