Menichini 2015.

Study characteristics
Patient sampling	Retrospective study
Patient characteristics and setting	Study location: Rome, Italy Study period: October 2012 to October 2013 Care setting: department of emergency radiology Mass casualty: no Participants enrolled: 73: 51 boys and 22 girls Participants included in analysis: 73 Age: mean age 8.7 ± 2.8 years (range not reported) Type of injury: low‐energy blunt abdominal trauma (minor trauma) Injury severity: not reported Haemodynamic stability: stable conditions Inclusion criteria: male or female, aged 0 to 16 years, haemodynamically stable children with a history of minor blunt abdominal trauma Exclusion criteria: > 16 years of age, haemodynamical instability, history of major trauma
Index tests	Index test: FAST, CEUS US protocol: 73 participants with a history of minor trauma, haemodynamic stability, and at least 1 positive finding at baseline US such as abdominal free fluid, perirenal fluid collection, signs of hepatic, splenic, or renal injury were subjected to both CEUS and CE‐MDCT. CEUS was performed immediately after baseline US. Hardware used: Acuson Sequoia 512 Ultrasound System (Siemens, Germany), equipped with both curved‐ and linear‐array probes Description of imaging technique: the study was conducted to detect the presence of free intraperitoneal fluid in the perihepatic area, Morison pouch, epigastric region, perisplenic region, paracolic gutters, and Douglas pouch, and the presence of perirenal fluid collection. Intra‐abdominal organs were evaluated specifically for evidence of injury. Adequate US technology consisting of contrast‐specific software that operates in real time at a low mechanical index (pulse inversion technology) was applied. 2 x 1.2 mL boluses of second‐generation blood pool contrast agent (SonoVue, Bracco, Italy) were administered through a 20‐gauge catheter in the antecubital vein, followed by saline (0.9%). An abdominal scan of 3 minutes folllowed each bolus, starting with the right and left kidney, liver and pancreas, and finally the spleen. A traumatic lesion was identified as the presence of a hypoechoic area that persisted unchanged during all the acquisition phases, with a subcapsular distribution in the case of haematoma, or a parenchymal localisation in the case of lacerations. The presence of intralesional hyperechoic spots was interpreted as a sign of active bleeding.
Target condition and reference standard(s)	Target condition: free fluid and air, organ injury Reference standard: CE‐MDCT, MDCT 16 scanner (LightSpeed 16, GE Healthcare, USA) Description of technique: the scanning parameters were as follows: 100 to 250 mAs (applied with the care‐dose technique and with a medium value of 115 mAs), 100 to 120 kV (according to physical build), 2.5‐mm collimation, 13.5 mm/s table, and 1‐mm reconstruction interval. A dose of 2.5 mL/kg of non‐ionic contrast agent (Xenetix 350, Guerbet, France) was injected at a rate of 1.5 mL/s to 2 mL/s. Arterial phase is performed with an acquisition delay of 40 s; a venous phase is routinely performed with 70‐second delay; late phase (5 minutes) was performed only in case of suspected urinary tract lesion. The presence of a parenchymal bleeding was defined as the presence of hyperechoic/hyperdense postcontrast intralesional spots.
Flow and timing	Time between US and reference standard: not reported
Comparative
Notes
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Did the study avoid inappropriate exclusions?	Yes
		Low	High
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	Unclear
If a threshold was used, was it pre‐specified?	Yes
Was the qualification of the US operator appropriate?	Yes
Was the US hardware (i.e. generation, manufacturer, probe, etc.) up to date?	Yes
Was the US protocol (i.e. 'classic' FAST) appropriate?	Yes
Are there concerns that the definition or performance of the index test (i.e. POC US of trauma) do not match generally accepted, established, or practiced rules or recommendations?	No
		Low	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
Was the qualification of the doctors (i.e. radiologists, surgeons, etc.) determining the reference standard appropriate?	Yes
Was the reference imaging standard (i.e. MDCT‐rows (4 to ≥ 256 slices), contrast‐imaging, etc.) up to date?	Yes
Are there concerns that the definition or performance of the reference tests (e.g. CT, MRI, laparatomy, thoracotomy, autopsy, etc.) do not match generally accepted, established, or practiced rules or recommendations?	Yes
		Low	High
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Did all patients receive the same reference standard?	No
Were all patients included in the analysis?	Yes
Did all participants receive a reference standard? (Risk of partial verification bias)	No
		High