Detection of the process of blood coagulation and clot formation using quantitative ultrasonic parameters

Ultrasonic parameters, including attenuation coefficient, sound velocity, and backscattered strength, were applied to detect the process of blood coagulation (BC) and clot formation (CF) in the porcine blood of different hematocrits. Fresh porcine blood added with a 10% of anticoagulant, ACD solution, was collected from a local slaughterhouse. After separation of the plasma and red blood cell by the centrifugation technique, blood was restituted into different hematocrits ranged from 25 to 55%. A 20 ml blood was added into a 56 ml container in which blood was stirred at 250 rpm using a magnetic stirrer. After three minutes, a 10 ml calcium chloride solution was subsequently added into the blood for re-calcifying. Backscattered signals and ultrasonic parameters were collected using a 5 MHz transducer and a digital acquisition system at one second time resolution to monitor the whole process of BC and CF for 50 minutes. Results showed that all three ultrasonic parameters are able to detect the process of BC and CF in which ultrasonic results as a function of time tend to increase largely during the process of BC and to saturate corresponding to the formation of clot. These results are consistent with that measurement of the blood viscosity as a function of time using a viscometric method. Moreover, the rates of ultrasonic parameters at the transition region between the increasing and saturating points, defined from a previous work using a viscometric method to characterize the intensity of CF by the rate of viscosity, were calculated. The increasing rate of attenuation coefficient ranged from approximately 4 to 10.2 dB/cm/min corresponded to the increase of blood hematocrit from 25 to 55%. A nearly linear relationship was found between the rate of attenuation coefficient and the rate of viscosity with the correlation coefficient of 0.9434. These results validate that ultrasound could be a sensitive modality to detect the process of BC and CF for assessing cardiovascular diseases.