Contrast enhanced ultrasound in abdominal trauma– a level one trauma centre experience

Contrast enhanced ultrasound (CEUS) is now established and widely used in many clinical settings outside the licensed areas of hepatic, breast, cardiac and vascular applications. The use of CEUS in acute blunt abdominal trauma has been shown to be rapid, safe, cost-effective, diagnostically accurate and, although lacking the global imaging capabilities of computed tomography (CT), CEUS has no radiation exposure. However, in the follow-up of conservatively treated solid organ injuries CEUS is likely to become more acceptable in clinical practice, primarily in order to avoid radiation exposure in the young patient. The current ‘gold standard’ for assessment of patients following blunt abdominal trauma is contrast enhanced computed tomography (CECT). Often this is preceded by a baseline ultrasound (US) or focused assessment with sonography in trauma (FAST scan) performed in the emergency department, aimed primarily at detecting free fluid in the abdomen, a marker of significant injury. The sensitivity of FAST scans in detecting free fluid in the abdomen ranges from 63-99%. However, the absence of haemoperitoneum or free fluid on US does not exclude a post-traumatic solid organ injury, with CECT providing a better overall assessment. There are circumstances following clinical evaluation when CECT is not the appropriate mode of imaging, for example, in patients with low impact injury and in imaging young stable patients. In this scenario, CEUS has been demonstrated to be beneficial, allowing for documentation of solid organ injury (liver, spleen and kidneys). It is also useful in patients who have localised symptoms following trauma. The sensitivity, specificity, positive and negative predictive value of CEUS at delineating solid organic traumatic lesions is 96.4%, 98%, 98.8% and 94.1% respectively.