Objective To observe the performance of CEUS in patients with suspected deep vein thrombosis (DVT) after bone injury

analyze the correlation between the TIC (time-intensity Curves) and the increased degree of plasma D-dimmer

Then discuss the value of CEUS in diagnosis of DVT in patients with bone injury. Methods A total of 57 suspected Deep venous DVT patients who were unable to be diagnosed by conventional ultrasound after lower limb fractures from May 2019 to May 2021 were collected

all of which has only one lower limb fractures

which could not be scanned under pressure due to fracture displacement and lower limb soft tissue swelling.The ipsilateral deep vein without thrombosis was used as the control vessel. Angiography was performed on 57 lower limbs to observe the contrast agent perfusion. TIC curve analysis and comparison were started after the angiography:Area under the curve

contrast agent arrival ATm (Start frame time of CINE)

time to peak intensity from the first frame of CINE (TtoPK)

the time of pesk intensity is calculated by C/K

and mean-square differential MSE: Mean Square Error between actual data and fitting curve

curve Gradient between Start frame to Peak frame

and dValue (The amount of intravascular abstract contrast agent increased) were compared and measured.The correlation between TIC curve and D-dimer concentration was analyzed.Results ①. Of the 57 patients

34 patients showed "truncation sign" the contrast agent filling defect of the thrombus.The incidence of PEV was higher than PTV

and the difference was statistically significant (χ2=13.342a

P<0.01).In 23 patients

the contrast agent arrived at the suspected thrombus slowly and showed slow flow. ②. TIC curve analysis was performed on 34 patients diagnosed with DVT: compared with control vessels

there were statistically significant differences in Area under the curve (T=6.265 P=0.018) and dValue (T=5.547 P<0.01). ③.Multivariate logistic regression showed that the more greater difference in dValue compared with the control vessels

the more possibility of thrombosis. P=0.041

95.0% C.I(1.012-1.730).