False Positives in HIDA

False positives for acute cholecystitis may be seen with HIDA scans in the following cases:

• Non-fasting state: Meal within 2-4 hours of scan. Intermittent contractions of the gallbladder will interfere with gallbladder filling.
• Prolonged fasting: > 24 hours. Due to full gallbladder. Sincalide administration empties gallbladder and may improve sensitivity.
• Total parenteral nutrition: Thought to be due to increased bile viscosity and decreased endogenous production of cholecystokinin. Sincalide administration empties gallbladder and may improve sensitivity.
• Alcoholism: Thought to be due to increased bile viscosity and abnormal hepatobiliary function.
• Acute pancreatitis: Nonvisualization of gallbladder may be transient. Delayed imaging is needed. Etiology unknown. May be due to disturbance of gallbladder motility.
• Recent narcotic use:
• Cystic duct obstruction: For example, cholangiocarcinoma.
• Hepatocellular disease: Decreased bile production may lead to nonvisualization of the gallbladder.
• Severe chronic cholecystitis: Sincalide administration empties gallbladder and may improve sensitivity.

Sincalide (0.04 mcg/kg in 10 cc saline) administration must be slow (over 5-10 minutes) to prevent gallbladder neck spasm and less complete emptying.

Delayed images up to 4 hours reduce false positive results in cases of chronic cholecystitis. Intravenous morphine may be used to shorten the study.

References

• Edlund G, Kempi V, van der Linden W. Transient nonvisualization of the gallbladder by Tc-99m HIDA cholescintigraphy in acute pancreatitis: concise communication. J Nucl Med. 1982 Feb;23(2):117-20.
• Klingensmith WC 3rd, Turner WM. Cholescintigraphy for acute cholecystitis: false positive results caused by chronic cholecystitis. Gastrointest Radiol. 1990 Spring;15(2):129-32.
• Mettler FA and Guiberteau MJ. Chapter 8. In Essentials of Nuclear Medicine Imaging. Fifth Edition. Saunders, Philadelphia. 2006. pp 222-223.
• Shuman WP, Gibbs P, Rudd TG, Mack LA. PIPIDA scintigraphy for cholecystitis: false positives in alcoholism and total parenteral nutrition. AJR Am J Roentgenol. 1982 Jan;138(1):1-5.