Is hepato-imino diacetic acid scan a better imaging modality than abdominal ultrasound for diagnosing acute cholecystitis?

• Diagnostic role of ultrasound and HIDA scan for acute cholecystitis examined.
• HIDA scan has significantly higher sensitivity and specificity than ultrasound.
• Positive and negative predictive values of HIDA scan are higher than ultrasound.
• HIDA scan significantly increases the accuracy of the correct diagnosis.
• If ambiguous or nonspecific ultrasound findings, workup with HIDA scan recommended.

BackgroundThe role of hepato-imino diacetic acid scan (HIDA) in the diagnosis of acute cholecystitis remains controversial when compared with the more commonly used abdominal ultrasound (AUS).MethodsThe diagnostic imaging workup of 1,217 patients who presented to the emergency department at a single hospital with acute abdominal pain and suspicion of acute cholecystitis was reviewed to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of AUS and HIDA.ResultsIn patients undergoing both imaging modalities, HIDA had significantly higher sensitivity (90.7% vs 64.0%, P < .001) and specificity (71.4% vs 58.4%, P = .005) than AUS for the diagnosis of acute cholecystitis. Additionally, PPV and NPV of HIDA (56.2% and 95.0%, respectively) were higher than PPV and NPV of AUS (38.4% and 80.0%, respectively) when both imaging modalities were used for the same patient.ConclusionIn adults with acute abdominal pain, HIDA significantly increases the accuracy of the correct diagnosis.