目的通过优化T2预脉冲时间和反转延迟时间以探讨参数优化后的无需对比剂和触发的松弛增强血管造影技术(Relaxation-Enhanced Angiography without Contrast and Triggering,REACT)技术在提高中心静脉图像质量中的作用。方法分别由低到...目的通过优化T2预脉冲时间和反转延迟时间以探讨参数优化后的无需对比剂和触发的松弛增强血管造影技术(Relaxation-Enhanced Angiography without Contrast and Triggering,REACT)技术在提高中心静脉图像质量中的作用。方法分别由低到高设置T2预脉冲时间(46、50、60、70、80、90、100、110 ms)和反转延迟时间(55、60、70、80、90、100、110、120、130、140、150 ms)进行胸部冠状位扫描,分别获得升主动脉、上腔静脉、左侧无名静脉、左侧锁骨下静脉、右侧无名静脉、右侧锁骨下静脉的信噪比,然后进行相关性分析。结果T2预脉冲时间设置为50 ms时,各段血管最大信噪比值出现的频率最高,比率为27.78%;反转延迟时间设置为130 ms时,各段血管最大信噪比值出现的频率最高,比率为20.69%。结论通过测试不同的T2预脉冲时间和反转延迟时间,发现当T2预脉冲时间为50 ms,反转延迟时间为130 ms时,中心静脉各段血管的信噪比最好,合理设置准备脉冲时间能提高REACT技术在中心静脉成像的图像质量。展开更多
Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit freq...Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies.For perfusion imaging,markers have been designed to enhance the contrast in B-mode imaging.These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells.In this review,the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described.Furthermore,an outline of clinical imaging applications of contrast-enhanced ultrasound is given.It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition,and how these phenomena may be utilized in ultrasonic imaging.Aided by high-speed photography,our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques.More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves,and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs.These are beginning to be accepted into clinical practice.In the long term,targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.展开更多
AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by...AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by feeding an MCDD,was examined by contrast ultrasonography at weeks 2,4,8,12 and 16,with late phase images of contrast ultrasonography(Kupffer imaging) in which contrast enhancement was achieved by incorporation of a contrast agent by Kupffer cells(KCs),and images were compared to those in rats taking a regular chow.RESULTS:Decrease in contrast enhancement was observed first in MCDD rats at week 2.KCs were counted based on immunohistochemistry,but their numbers were not reduced and it was assumed that attenuation of contrast enhancement was attributable to reduced phagocytic activity of the KCs.CONCLUSION:It is suggested that clinical application of contrast ultrasonography may be valuable for noninvasive diagnosis of NASH.展开更多
文摘Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies.For perfusion imaging,markers have been designed to enhance the contrast in B-mode imaging.These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells.In this review,the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described.Furthermore,an outline of clinical imaging applications of contrast-enhanced ultrasound is given.It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition,and how these phenomena may be utilized in ultrasonic imaging.Aided by high-speed photography,our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques.More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves,and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs.These are beginning to be accepted into clinical practice.In the long term,targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.
文摘AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by feeding an MCDD,was examined by contrast ultrasonography at weeks 2,4,8,12 and 16,with late phase images of contrast ultrasonography(Kupffer imaging) in which contrast enhancement was achieved by incorporation of a contrast agent by Kupffer cells(KCs),and images were compared to those in rats taking a regular chow.RESULTS:Decrease in contrast enhancement was observed first in MCDD rats at week 2.KCs were counted based on immunohistochemistry,but their numbers were not reduced and it was assumed that attenuation of contrast enhancement was attributable to reduced phagocytic activity of the KCs.CONCLUSION:It is suggested that clinical application of contrast ultrasonography may be valuable for noninvasive diagnosis of NASH.
