IOTW 11/02/20

38 y/o F p/w RUQ pain

  1. Does this gallbladder contain gallstones?
    • Yes. Although gallstones are not seen on this CT, they are easily visualized on the ultrasound (see image below answers) Only 74-79% of stones are identified on CT scan. Typically they are only seen on CT if they are calcified, whereas cholesterol stones and others may be hypoattenuating or isodense to bile, rendering them non-distinguishable. Ultrasound is considered the gold standard for detecting gallstones which can identify stones as small as 2 mm with a sensitivity of greater than 95%.
  2. Which label (A, B, or C) is the most accurate GB wall measurement and is it abnormal?
    • A is the most accurate measurement in this image corresponding to a wall thickness of approximately 1.8 cm. Wall >4 mm (with some sources even stating 3 mm) is considered abnormal. Label B may be tempting to select, however this only measures from the inner wall to a region of wall edema, which would lead to a greatly under-measured wall. Label C measures the posterior wall, which would falsely enhance the measurement due to the artifact posterior acoustic enhancement. Due to this artifact, only the anterior gallbladder wall should ever be measured when performing biliary ultrasound.
  3. Is this a contracted gallbladder or is there wall edema? How does the sonographic appearance of these differ?
    • This is gallbladder wall edema. Note the irregular anechoic and hypoechoic areas within the wall. A contracted gallbladder will show pseudothickening which tends to form a more symmetric and diffuse pattern. Wall edema may be focal or more diffuse with irregular areas demonstrating various echogenicities. (See images below answers)
  4. What is represented by label D?
    • Pericholecystic fluid. It can often be subtle, so be sure to have a keen eye.
  5. Are these images overall consistent with cholecystitis?
    • Yes. Gallbladder wall thickening and pericholecystic fluid are secondary findings of cholecystitis and have a low specificity alone. The presence of gallstones with wall thickening, however, has been shown to have a positive predictive value of >95% for cholecystitis.
Gallstones. Note the hyperechoic rims with shadowing posteriorly
Contracted gallbladder on left exhibiting pseudothickening. Gallbladder wall edema on right.

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