The study protocol was approved by the Hospital ethic board and written informed consent was obtained from parents.
From February to October 2012,
127 consecutive patients with history of minor blunt abdominal trauma presented to our Department and were evaluated for study eligibility (Fig. 1).
Vital sign recording,
laboratory tests,
and baseline US to detect free abdominal fluid as a routine trauma protocol,
were performed.
Seven patients were excluded from the study because showed hemoperitoneum at US examination and unstable vital signs and were immediately referred to surgery.
Eighty-five patients with negative US findings and with a minor injury according to the Abbreviated Injury Scale [1] were discharged after 24 h of observation and did not undergo further abdominal imaging.
Thirty-five hemodynamically stable patients (21M and 14F; mean age 8.7±2.8 years old) with moderate or severe injuries according to the Abbreviated Injury Scale and with positive US findings were included in the study and evaluated with both CEUS and CE-MDCT.
The main vital sign and liver and kidney laboratory tests were recorded to evaluate any adverse effect due to contrast medium administration.
US,
CEUS and CT were performed and interpreted by three different radiologists with at least 10 years of experience in the Emergency Department,
blinded to the results of the other examinations.
CEUS was performed immediately after baseline-US.
Adequate ultrasound technology – performed using a SIEMENS SEQUIOA 512 CPS (Siemens Medical Systems,
Forchheim,
Germany) equipped with a curved-array probe,
was used.
A contrast specific-software which operate in real-time at a low mechanical index (pulse inversion technology) was applied.
Two 1.2 mL bolus of second-generation blood pool contrast agent (Sonovue; Bracco,
Milan – Italy),
were administered through a 22-gauge catheter placed in an antecubital vein,
followed by saline.
An abdominal scanning of 3 consecutive minutes was performed for each bolus,
starting from the right kidney,
followed by left kidney,
liver,
spleen and pancreas (Fig. 2).
The second bolus injection was applied to complete the study and to confirm the suspected traumatic lesion identified in the first examination.
By-phasic CE-MDCT examination was performed using a MDCT 16 scanner (LightSpeed RT16 – GE Healthcare,
Milan Italy).
A dose of 2.5 mL/Kg of non-ionic contrast agent (Omnipaque 350 – GE Healthcare,
Milan Italy) was injected at a rate of 1.5 mL/sec with an acquisition delay of 50 seconds and if necessary a delated phase (70 sec for the active venous bleeding – 3/5 minutes for urinomas).
CT lesions were scored with the Organ Injury Scale of the American Association for the Surgey of Trauma [2].
Sensitivity,
specificity and positive and negative predictive values were determined for US and CEUS compared to MDCT.