Objectives: We aimed to explore the value of contrast-enhanced ultrasound combined with micro-flow imaging technology (MFI) ( referred to as “dual micro-imaging”) for the diagnosis of active bleeding from abdominal parenchymal organs. We also wanted to explore the location of active bleeding by establishing an externally active bleeding model by combining these two techniques. Methods: Artificial blood vessels were designed using silicone tubes (diameters of 0.5/1.0mm) to establish two in vitro active bleeding models: ① The tank model

where the free end of the artificial blood vessel was placed into a water tank containing ultrasound contrast agent used to simulate the enhanced organ parenchyma; ② The tissue damage model

where a closed traumatic wound was established by a self-made small impactor in the selected area of the isolated pig liver and the free end of the artificial blood vessel was placed into the traumatic lesion to simulate the performance of bleeding in the traumatic tissue. The contrast agent was injected using a syringe pump connected to the artificial blood vessel and the flow rate was selected from a total of 20 flow rates within the range of 5-100ml/h at an interval of 5ml/h. The contrast agent solution was injected through the syringe pump and contrast-enhanced ultrasound and "dual micro-imaging" technology were activated for observation. According to the criteria for diagnosing and locating active bleeding

two physicians used a double-blind method to independently complete readings of the images. Measurement data were normally presented as mean ± standard deviation (\bar{x}\ ± s) and a paired t-test was used to compare groups. Finally

a chi-square test was used to analyze count data. Results: 1. In the tank model

the contrast-enhanced ultrasound failed to diagnose active bleeding (0/40) and the accuracy of "dual micro-imaging" in diagnosing and locating active bleeding was 62.50% (25/40). 2. In the tissue damage model

the accuracy of contrast-enhanced ultrasound in diagnosing and locating active bleeding was 77.50% (31/40) and 62.50% (25/40)

respectively

and this difference was statistically significant (χ2=19.355

p=0.000). The accuracy of "dual micro-imaging" in the diagnosis and location of active bleeding was 90.00% (36/40) for both and the difference of accuracy compared with contrast-enhanced ultrasound was statistically significant (χ2=15.309

p=0.000; χ2=7.407

p= 0.006). 3. In the tank and the tissue damage models

the accuracy of "dual micro-imaging" in locating active bleeding was 62.50% (25/40) and 90.00% (36/40)

respectively

and this difference was statistically significant (χ2=7.407

p=0.006 ).Conclusions: Compared with contrast-enhanced ultrasound

contrast-enhanced ultrasound combined with micro-flow imaging technology (dual micro-imaging) not only improves the accuracy for diagnosing active bleeding

but also improves identifying the location of active bleeding.