E2282. Diagnosis of Acute Cholecystitis: New Paradigms
  1. Richa Patel; Stanford University
  2. Aya Kamaya; Stanford University
The diagnosis of acute cholecystitis has historically been considered simple and straightforward, while in reality, it remains challenging to diagnose accurately. Old paradigms in the diagnosis suggest the presence of gallstones and a sonographic Murphy’s sign are adequate with a 92% positive predictive value and 95% negative predictive value. However, these statistics are irreproducible, and in practice miss up to 76% cases of acute cholecystitis. Similarly, recent literature suggesting that CT is equivalent to ultrasound (US) for diagnosis are significantly hampered by selection bias; patients who undergo CT for right upper quadrant pain are typically preselected because they undergo US first. CT performed after US examinations have the benefit of progression of inflammation which simplifies diagnosis. HIDA has reported highest diagnostic accuracy in diagnosis for acute cholecystitis but due to the time consuming nature of the examinations (~4 hours) and inaccessibility after hours, this is not feasible for first line in evaluation of right upper quadrant pain. We advocate for utilizing new imaging paradigms to significantly improve accuracy in diagnosis of acute cholecystitis in the setting of right upper quadrant pain.

Educational Goals / Teaching Points
We will discuss the reasons why old paradigms in diagnosis of acute cholecystitis were limited. We will review multiple examples of better imaging findings that may be more helpful in diagnosis of acute cholecystitis and review the literature.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Old paradigm imaging findings in the diagnosis of acute cholecystitis include presence of gallstones, sonographic Murphy’s sign, wall thickening, and pericholecystic fluid. New paradigm imaging findings in the diagnosis of acute cholecystitis include increased intraluminal pressure as manifested by distended gallbladder and bulging gallbladder fundus, impacted gallstones, gallbladder wall hyperemia as quantified by elevated cystic artery and hepatic artery velocities, presence of gallbladder sludge, inflamed pericholecystic fat manifested by either echogenic pericholecystic fat on US or pericholecystic fat stranding on CT, and gallbladder mucosal discontinuity. We will provide a simple flow chart that will provide guidance for improved diagnosis.

New paradigm imaging findings are more predictive of acute cholecystitis and furthermore, many can be applied in practice to both CT and US.