Contrast-enhanced US enhancement patterns were different in benign and malignant lesions. Ring enhancement was predictive of benign lesions, whereas heterogeneous enhancement was helpful for detecting malignant lesions.
An ultrasound contrast agent (UCA) plays a key role in ultrasound imaging to precisely diagnose coronary heart disease. Microcapsules composed of inner gas and shell materials are most commonly employed as ultrasound contrast agents. The ultrasonic properties of the microcapsules are significantly dependent on their size and size distribution. Herein, we prepared several uniform sized biodegradable polylactone microcapsules by combining a premix membrane emulsification technique and W/O/W method. We investigated various size-dependent factors to optimize the size and size distribution of the microcapsules. After evaluation for ultrasound imaging, $4 mm PLLA (poly(L-lactide)) microcapsules generated more intense ultrasound signals than PLGA7030 or PLGA5050 (poly(lactic-co-glycolic acid), the molar ratio of lactic acid and glycolic acid being 70 : 30 or 50 : 50), PEG-b-PLGA7030 (poly(ethylene glycol)-blockpoly(lactic-co-glycolic acid)), PLC5050 (poly(L-lactide-co-caprolactone), the molar ratio of lactide and caprolactone being 50 : 50) and PEG-b-PLLA microcapsules. The signal duration of the PLLA and PEG-PLLA microcapsules could reach ca. 3 and 3.5 min continuously. The ultrasound signal intensity and duration of the signals of PLLA microcapsules were considerably stronger and longer than those of commercially available UCAs, showing that the PLLA microcapsules have a great potential as more efficient UCAs for biomedical imaging.
BackgroundThis paper presents quantitative analysis of blood flow shear stress by measuring the carotid arterial wall shear stress (WSS) and the intima-media thickness (IMT) of experimental rabbits fed with high-fat feedstuff on a weekly basis in order to cause atherosclerosis.MethodsThis study is based on establishing an atherosclerosis model of high-fat rabbits, and measuring the rabbits’ common carotid arterial WSS of the experimental group and control group on a weekly basis. Detailed analysis was performed by using WSS quantification.ResultsWe have demonstrated small significant difference of rabbit carotid artery WSS between the experimental group and the control group (P<0.01) from the 1st week onwards, while the IMT of experimental group had larger differences from 5th week compared with the control group (P<0.05). Next, we have shown that with increasing blood lipids, the rabbit carotid artery shear stress decreases and the rabbit carotid artery IMT goes up. The decrease of shear stress appears before the start of IMT growth. Furthermore, our receiver operator characteristic (ROC) curve analysis showed that when the mean value of shear stress is 1.198 dyne/cm2, the rabbit common carotid atherosclerosis fatty streaks sensitivity is 89.8%, and the specificity is 81.3%. The area under the ROC curve is 0.9283.ConclusionsAll these data goes to show that WSS decreasing to 1.198 dyne/cm2 can be used as an indicator that rabbit common carotid artery comes into the period of fibrous plaques. In conclusion, our study is able to find and confirm that the decrease of the arterial WSS can predict the occurrence of atherosclerosis earlier, and offer help for positive clinical intervention.
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