Q: What is the cutoff point for the thickening of the gallbladder in acalculous cholecystitis on ultrasound?


Answer: 3 to 3.5 mm

Ultrasound is preferable in patients suspected of having acalculous cholecystitis as it is noninvasive, can be done at the bedside, and has good sensitivity and specificity. Thickening of the gallbladder wall is the most reliable feature seen in patients with acalculous cholecystitis. Using a cutoff of 3.5 mm, ultrasonography has a sensitivity of 80 percent and a specificity of 99 percent for detecting acalculous cholecystitis. If a cutoff of 3 mm is used, the sensitivity is 100 percent with a specificity of 90 percent.