Use of Acoustic Radiation Force Impulse Elastography to Predict Acute Pancreatitis: A Case-Control Study

Abstract

Diagnosis of uncomplicated acute pancreatitis (AP) by trans-abdominal ultrasonography is not sensitive. We try to demonstrate the potential value of acoustic radiation force impulse (ARFI) elastography on prediction of AP. We performed ARFI elastography (Siemens Acuson S2000™ ultrasound system: median value of 3 valid measurements and median value, meters/second (m/s)) on 20 AP patients and 43 control patients who received ultrasonography for indications other than AP (non-AP group) between March 2016 and March 2017. Measurement of ARFI at pancreatic body was carried out via transhepatic route. The ARFI mean values, clinical and laboratory data of two groups were analyzed. More male patients was noted in AP group (male 80.0% vs. 37.2%, p=0.002).The mean age of AP and non-AP groups were 42.80 ± 10.67 years and 49.70 ± 15.79 years (p=0.08), respectively. Etiologies for AP were alcohol (13/20, 65%), followed by biliary tract stones (3/20, 15%), hypertriglyceridemia (2/20, 10%), and unknown cause (2/20, 10%). Most (18/20, 90%) of ARFI elastography in AP group were performed within 24 hours after the hospitalization. The mean values of ARFI in AP and non-AP groups were 1.88 ± 0.72 m/s and 1.13 ± 0.29 m/s (p<0.001), respectively. Higher ARFI values were found in alcohol (2.08 ± 0.80, p<0.001) and hypertriglyceridemia (1.66 ± 0.10, p=0.003) related AP than controls. Using cut-off value of ARFI 1.32 m/s for diagnosis of AP had sensitivity and specificity of 85.0% and 79.1%, respectively (AUC ROC 0.86). ARFI elastography had no value in prediction of serum lipase level (P=0.412), BISAP score (P=0.936) and the length of hospitalization days (P=0.831). Higher ARFI was found in AP patients, especially for alcohol and hypertriglyceridemia related causes. However, the value of ARFI was not associated with clinical severity. Further study with larger number of study subjects is warranted to demonstrate the diagnostic and prognostic role of ARFI elastography in AP patients.