[Clinical study of real-time shear wave elastography for diagnosis of severity of acute cholecystitis]

Objective: To assess the clinical value of real-time shear wave elastography (SWE) in distinguishing between mild and severe cholecystitis. Methods: A total of 176 patients with cholecystitis who meet the criteria of Tokyo Guideline in Wuxi People's Hospital of Nanjing Medical University from January 2017 to March 2018 were recruited, 95 male, 81 female, age range of 23-88 years, average age (48±16)years, and divided into severe (91 cases) and mild (85 cases) groups according to disease severity. All patients underwent routine ultrasound and SWE examination to assess gallbladder morphology, hepatic flow signals and liver cirrhosis adjacent to the gallbladder. Two sonographers with different diagnostic experience independently reviewed ultrasound images alone and in combination with SWE, respectively, and compared the diagnostic consistency of two sonographers in assessing severe cholecystitis. Results: The SWE value of liver in the severe group of cholecystitis was significantly higher than that of mild group (t=10.34, P=0.01). The area under the ROC curve of SWE value for diagnosing severe cholecystitis was 0.809 with the optimal cut-off value of 7.2 kPa. The sensitivity, specificity was 78.0% and 83.5%, respectively. In distinguishing between mild and severe cholecystitis, the diagnostic sensitivity (84.6%, 95.6%) was high and the specificity (49.4%, 35.3%) was low in diagnosing gallbladder edema and sludge.The diagnostic sensitivity (14.3%, 26.4%) was low and the specificity (100%, 95.3%) was high in diagnosing pericholecystic fluid and blood flow signal of the gallbladder wall.Two sonographers reviewed ultrasound images independently for diagnosing severe cholecystitis in good agreement (κ =0.75). Combining SWE to conventional ultrasound, the diagnostic consistency of the two sonographers in diagnosing server cholecystitis was excellent (κ=0.86), and the difference was statistically significant (P=0.02), the diagnostic efficacy of which was higher than that of conventional ultrasound alone. Conclusions: Compared with conventional ultrasound alone, combining with SWE can improve the diagnostic efficacy of distinguishing between mild and severe cholecystitis, and the clinical experience of sonographers has less influence on the diagnostic accuracy.