Real-time, contrast-enhanced sonographic imaging in emergency radiology

To report our pilot experience in the evaluation of traumatic and nontraumatic emergencies with contrast-specific, continuous-mode sonography (US) and a second-generation contrast medium.

Between January 2002 and December 2003 we evaluated 126 acute patients by using real-time contrast-specific US: blunt abdominal trauma (76 cases), penetrating abdominal trauma (3), blunt scrotal trauma (1), right upper abdominal pain (10), left upper abdominal pain (9), epigastric pain (2), flank pain (5), right lower abdominal pain (2), scrotal pain (7), postoperative abdominal sepsis (1), post-biopsy haemorrhage (1), ruptured abdominal aortic aneurysm (8), postsurgical aortic bleeding (1). In all cases the radiologist performed a complete baseline US survey and then decided whether or not to add a contrast-enhanced examination.

All contrast-enhanced sonographic studies were completed proving to be adequate for diagnostic purposes and without adverse reactions to contrast medium. There were 40 true negatives. The final diagnosis, obtained in 85 positive cases out of 86, was: splenic injury (28 cases), hepatic injury (3), renal injury (3), multiple injuries (3), pancreatic and portal vein injury (1), colonic-mesocolic injury (1), testicular trauma (1), hepatic abscess (9), hepatic ischaemia (1), gangrenous cholecystitis (1), splenic infarction (8), splenic haematoma abscess (1), renal infection (4), renal infarction (1), necrotizing pancreatitis (1), post-biopsy haemorrhage (1), appendicitis (2), peritoneal abscesses (1), testicular torsion (6), orchiepididymitis (1), iliac artery dissection (1), ruptured abdominal aortic aneurysm (6), aortic periprosthetic hemorrhage (1). Out of 85 positive cases, agreement between baseline US and contrast-specific US was absent in 8% of cases, low in 26%, intermediate in 42%, and high in 24%. Baseline US had 3 false positives. Relevance of contrast-specific US was absent in 17% of cases, low (additional data not relevant for patient management) in 26%, intermediate (relevant additional data not modifying patient management) in 34%, and high (additional data modifying patient management) in 23%. Agreement between contrast-specific US and the gold standards was absent in 0% of cases, low in 6%, intermediate in 38%, and high in 56%. Contrast-specific US had 2 false positive results.

Real-time contrast-specific US is an effective technique in emergency imaging. Its role should not be considered as a replacement of CT (though in some instances it can be considered a valuable alternative) but as a useful integration of conventional US. By always having the opportunity to add contrast-enhanced imaging, in case of interpretation doubts or diagnostic difficulties, the radiologist can assess the emergency patient with improved confidence and skill.