Selective Perfusion Imaging with Intravenous Myocardial Contrast Echocardiography

背景：静脉心肌声学造影(MCE)不能单独识别冠状动脉的各个灌注区。然而，在静脉MCE中使用高功率超声破坏穿过特定血管的微泡，血管选择性灌注成像(VSPI)可能是可行的。方法：在10只开胸犬身上，使用Sequoia 512系统在Definity输液过程中获得间歇性短轴图像。对于VSPI，S3探头与SONOS5500相连，放置在左回旋支(Lcx)近端。发射高功率超声脉冲以破坏通过Lcx动脉的气泡。VSPI的阴性对比区被认为代表Lcx动脉的灌注区(Lcx-VSPI)。以常规MCE在Lcx闭塞时的阴性对比区(Lcx-OCC)和未被Evans蓝染色的区域(Lcx-EB)作为确定Lcx灌注区的金标准。结果：高功率破坏性脉冲在无Lcx动脉闭塞的情况下，可在Lcx区域形成一定范围的负对比。超声脉冲功率降低导致阴性对比区消失。Lcx-VSPI与Lcx-OCC(r=0.93，P&t；.0001)、Lcx-VSPI与Lcx-EB(r=0.92，P=.0002)均呈良好的相关性。结论：静脉MCEVSPI可用于无创性评价特定血管的灌注区。

Background : Intravenous myocardial contrast echocardiography (MCE) cannot identify each perfusion area of coronary vessels separately. However, by destroying microbubbles passing through a specific vessel using high-power ultrasound during intravenous MCE, vessel-selective perfusion imaging (VSPI) may he feasible.Methods : In 10 open-chest dogs, intermittent short-axis images were obtained during Definity infusion using a Sequoia 512 system. For VSPI, an S3 probe coupled to a Sonos 5500 was placed on the proximal left circumflex(LCx) artery. High-power ultrasound pulses were transmitted to destroy bubbles passing through the LCx artery. A negative contrast area on VSPI was considered to represent the perfusion area of the LCx artery (LCx-VSPI). A negative contrast area on conventional MCE during LCx occlusion (LCx-Occ) and a region without staining by Evans blue dye (LCx-EB) were used as gold standards for defining the LCx perfusion area. LCx-VSPI was compared with LCx-Occ and LCx-EB.Results : Despite lack of LCx artery occlusion, high-power destructive pulses produced a definite area of negative contrast on the LCx region. Decreased power of ultrasound pulses resulted in disappearance of the negative contrast area. An excellent relationship was demonstrated between both LCx-VSPI and LCx-Occ (r=0.93,P<.0001), and LCx-VSPI and LCx-EB (r=0.92,P=.0002).Conclusion : VSPI during intravenous MCE may be feasible for noninvasive assessment of perfusion areas associated with specific vessels.