Comparative evaluation of ultrasound and computed tomography in the detection of imaging findings and complications of acute cholecystitis: a retrospective cohort study

Background: Gallstones (cholelithiasis) are common, with a significant portion of affected individuals developing acute cholecystitis, which can lead to severe complications. While ultrasound (US) is typically the first imaging method used, multidetector computed tomography (MDCT) may be better at detecting more complex scenarios. This study aimed to compare the detection of imaging features and complications of acute cholecystitis between US and MDCT in a cohort of confirmed cases, and to evaluate their complementary roles in clinical practice. Methods: A retrospective study was conducted including 134 adults with clinically suspected acute cholecystitis who underwent same-day US and MDCT, with subsequent confirmation by pathology or intervention. Two radiologists independently reviewed all imaging studies, and the detection of imaging features and complications was compared. Results: US showed significantly higher detection rates than MDCT for gallbladder wall thickening (98.5% vs. 66.4%, P < 0.001), sludge (35.1% vs. 14.9%, P < 0.001), and pericholecystic fluid (75.4% vs. 47.8%, P < 0.001). Conversely, MDCT more frequently identified complications such as choledocholithiasis (8.2% vs. 2.2% by US, P = 0.041) and liver abscesses (6.7% vs. 1.5% by US, P = 0.035). MDCT also identified findings consistent with cholecystitis in 7 patients (5.2%) not detected by US and was associated with a change in management of 20 patients (14.9%). Conclusions: US remains effective as a first-line modality for detecting acute cholecystitis, while MDCT offers additional value in identifying complications and influencing management. Together, these findings support a complementary, rather than substitutive, role for the two modalities.