From Anatomy to Functional and Molecular Biomarker Imaging and Therapy: Ultrasound Is Safe, Ultrafast, Portable, and Inexpensive.
From Anatomy to Functional and Molecular Biomarker Imaging and Therapy: Ultrasound Is Safe, Ultrafast, Portable, and Inexpensive.
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DOI：
10.1097/rli.0000000000000675
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发表时间：
2020-09
影响因子：
6.7
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中科院分区：
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超声波是全球使用最广泛的医学成像模式。它是丰富的，非常安全，便携和廉价。在这篇综述中，我们考虑了超声成像的一些当前发展趋势，这些趋势建立在其当前的实力和在医学成像专业用户中的普及程度之上。超声已迅速扩展到传统的放射科和心脏病学实践之外。通常可用的电子设备的计算能力和数据处理能力将超声系统放在实验室外套口袋中或用户的移动的电话上。利用超声物理学、信号处理算法和电子学中的新贡献和发现，超声系统和换能器的性能在变得更小、具有更高的成像性能和具有更低的成本方面有所进步。超声波以真实的时间运行，现在以超快的速度运行：许多系统已经实现了KHz的帧速率。超声已经发展到超出解剖成像和监测大血管中的血流。随着在血流中施用的超声造影剂（充气微泡）的临床批准，组织灌注研究现在是常规的。通过使用现代超声脉冲序列，可以真实的时间检测和观察具有亚皮克质量的个体微泡，其在身体中的深度为许多厘米。超声成像已经打破了波长障碍：通过跟踪微泡在脉管系统内的位置，超分辨率成像已经成为可能。超声波现在可以追踪最小的血管和毛细血管，并获得这些血管中的血流速度数据。分子超声成像现在已经更接近临床：使用对内皮生物标志物具有特异性亲和力的微泡，可以在缺血性损伤、炎症或新生血管形成区域选择性积累和保留超声造影剂。这将有助于非侵入性分子成像，并可能为活检、手术和消融手术的实时指导提供额外帮助。超声场可以在身体内紧密聚焦，深度为几厘米，精度为毫米，并通过能量沉积消融病变，具有热或机械生物效应。其中一些治疗方法已经在临床使用，更多的适应症正在进入临床试验阶段。与血管内微泡结合，聚焦超声可用于组织特异性药物输送：从血液中的颗粒中局部触发释放隔离药物可能需要时间才能到达诊所。血管内微泡与循环药物和低功率超声的组合允许短暂打开血管内皮屏障，包括血脑屏障;该方法已进入临床试验阶段。因此，通常不会到达大脑中的靶组织的药物现在将有机会产生治疗效果。总体而言，医学超声正在以快速的速度发展，即使在其他成像方式也在快速发展并且可能被认为更有利可图的环境中。随着我们讨论的所有当前进展，以及更多的进展，超声可能有助于解决现代医学面临的许多问题。
Ultrasound is the most widely used medical imaging modality worldwide. It is abundant, extremely safe, portable and inexpensive. In this review, we consider some of the current development trends for ultrasound imaging, which build upon its current strength and the popularity it experiences among medical imaging professional users. Ultrasound has rapidly expanded beyond traditional radiology departments and cardiology practices. Computing power and data processing capabilities of commonly available electronics put ultrasound systems in a labcoat pocket or on a user’s mobile phone. Taking advantage of new contributions and discoveries in ultrasound physics, signal processing algorithms, and electronics, the performance of ultrasound systems and transducers have progressed in terms of them becoming smaller, with higher imaging performance, and having lower cost. Ultrasound operates in real time, now at ultrafast speeds: KHz frame rates are already achieved by many systems. Ultrasound has progressed beyond anatomical imaging and monitoring blood flow in large vessels. With clinical approval of ultrasound contrast agents (gas-filled microbubbles) that are administered in the bloodstream, tissue perfusion studies are now routine. Through the use of modern ultrasound pulse sequences, individual microbubbles, with sub-picogram mass, can be detected and observed in real time, many centimeters deep in the body. Ultrasound imaging has broken the wavelength barrier: by tracking positions of microbubbles within the vasculature, super-resolution imaging has been made possible. Ultrasound can now trace the smallest vessels and capillaries, and obtain blood velocity data in those vessels. Molecular ultrasound imaging has now moved closer to clinic: the use of microbubbles with a specific affinity to endothelial biomarkers allows selective accumulation and retention of ultrasound contrast in the areas of ischemic injury, inflammation, or neoangiogenesis. This will aid in non-invasive molecular imaging, and may provide additional help with real-time guidance of biopsy, surgery, and ablation procedures. The ultrasound field can be tightly focused inside the body, many centimeters deep, with millimeter precision, and ablate lesions by energy deposition, with thermal or mechanical bioeffects. Some of such treatments are already in clinical use, with more indications progressing through the clinical trial stage. In conjunction with intravascular microbubbles, focused ultrasound can be used for tissue-specific drug delivery: localized triggered release of sequestered drugs from particles in the bloodstream may take time to get to clinic. A combination of intravascular microbubbles with circulating drug and low power ultrasound allows transient opening of vascular endothelial barriers, including blood brain barrier; this approach has reached clinical trial stage. Therefore, the drugs that normally would not be getting to the target tissue in the brain will now have an opportunity to produce therapeutic efficacy. Overall, medical ultrasound is developing at a brisk rate, even in an environment where other imaging modalities are also advancing rapidly and may be considered more lucrative. With all the current advances that we discuss, and many more to come, ultrasound may help solve many problems that modern medicine is facing.