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| The acoustic densitometry analysis about relationship of trigger intervals and effects in normal liver with high mechanical index contrast imaging |
| WU Feng-lin, LI Ying-jia, LI Chuan-gang |
| Department of Ultrasound, Nanfang Hospital, Nanfang Medical University, Guangzhou 510515, China |
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Abstract Objective: To have a acoustic densitometry(AD) analysis about the relationship between trigger intervals and effects in experimenting normal liver with high mechanical index(HMI) contrast imaging. Methods?押 Ten cases of normal liver were examined with HMI contrast imaging and the contrast agents were administrated through forearm veins at 0.3ml, trigger intervals being set at 1.0s, 2.0s, 3.0s, 4.0s respectively. The grey scale changes of imaging enhanced by contrast agents were analyzed with time-intensity cure method. The values of peak intensity(PI), area under curve(AUC), half time of descending(HT), mean transit time(MTT) were measured. Results: The time-intensity curves were almost similar at every trigger intervals, with a single-peak-shaped, looking like “a triangle”, which could be divided ascending, peak and descendent periods. but its amplitudes were different. The values of PI, AUC, HT, MTT and the effects of enhancement were gradually increased following trigger intervals increase from 1.0s to 3.0s. The values of PI, AUC, HT, MTT and the effects of enhancement were not increased any more at intervals of 4.0s and the values of PI, AUC, HT, MTT were almost similar with that measured at an interval of 3.0s, with no significant difference. Conclusion: The effects of enhancement in HMI contrast imaging can be directly influenced by trigger intervals. Following the trigger intervals increase, the effects can become stronger. But if the trigger intervals were too long, the effects increased no more.
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Received: 19 December 2005
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2006, Vol. 17 
