Liver trauma diagnosis with contrast-enhanced ultrasound: interobserver variability between radiologist and emergency physician in an animal study

Objective: The purpose of our study was to evaluate interobserver variability between the radiologist and emergency physician in detecting blunt liver trauma by conventional and contrast-enhanced ultrasound (US) (CEUS).

Methods: We created 20 sites of blunt liver trauma in rabbits and performed conventional US and CEUS on the animals. A radiologist and an emergency physician independently evaluated the degree of liver trauma. Using contrast-enhanced computed tomography as a reference standard, the diagnostic performance of US and CEUS was calculated. Interobserver variability between radiologist and emergency physician was compared before and after contrast enhancement of US.

Results: Overall sensitivity and specificity for detecting liver trauma on conventional US, regardless of the degree of trauma, were 61.1% and 100% for the radiologist and 50% and 100% for the emergency physician. On CEUS, the sensitivity and specificity were 94.4% and 100% for both the radiologist and emergency physician. The interobserver agreement between emergency physician and radiologist increased from 0.867 to 0.955 after contrast enhancement on US.

Conclusions: Contrast-enhanced US may permit a more accurate diagnosis for liver trauma than conventional US by both the radiologist and emergency physician. Contrast-enhanced US may also reduce interobserver variability for this diagnosis.