Contrast enhanced ultrasound with second generation contrast agent in traumatic liver lesions

To evaluate the accuracy of second generation contrast enhanced US (Sonovue) in the diagnosis and staging of traumatic hepatic lesions, compared with conventional US and spiral CT.

A total of 203 patients (127 males, 76 females, mean age 36 years) with isolated abdominal trauma were examined with conventional and contrast enhanced US (Sonovue, Bracco, Italy) between March 2002 and February 2003. The sonographic contrast agent was administered at a dose of 2 ml/10-15", repeated twice. CT examinations were performed with single- (Rhota, Esaote Biomedica, Italy) or multislice spiral CT with administration of contrast agent. The presence and number of lesions, hepatic capsular involvement, size and sonographic pattern were evaluated.

Conventional US demonstrated hepatic lesions in 27 patients, in 3 cases it identified 2 foci (30 lesions, size 2-8 cm). Contrast enhanced US (CEUS) revealed another 2 lesions and in 4 patients it identified lesions not shown at conventional US (size 2-5 cm). Capsular involvement was detected in 14 cases (11 with conventional US). The sonographic pattern of the lesions at conventional US was hypo-anechoic in 19 cases, and hyperechoic in 11. In CEUS all the lesions appeared strongly hypoechoic against a strongly hyperechoic parenchyma, with clear borders and larger size as compared with conventional US.

In isolated blunt abdominal trauma CEUS is more accurate than conventional US in determining the number and size of lesions and detecting capsular involvement. This has a strong impact on diagnosis as the number of false negatives is reduced and on prognosis as the lesions are more accurately graded, and there is close correlation with spiral CT. CEUS can be used as a first approach in mild isolated abdominal trauma, in paediatric patients and in the follow-up, whereas CT is the method of choice in severe trauma and in multiple traumas.