Therapeutic ultrasound in cardiology

Ultrasound can be exploited to derive therapeutic results by using its bioeffects such as creation of mechanical vibrations, localized cavitations, microstream formation, physicochemical changes and thermal energy. Extensive in vitro and animal investigations during the last 2 decades have laid a foundation for ultrasound energy to be used for treatment purposes in various medical specialties. In the area of cardiovascular diseases, ultrasound could be used for thrombolysis, adjunct to coronary interventions, drug delivery, local gene transfer, and creating therapeutic lesions. The dispensation approaches to therapeutic ultrasound are varied, from the use of low- to medium-range frequency, low to focused high intensity, and catheter-based to external devices. Catheter-based ultrasound could be useful for intracoronary thrombolysis, and external ultrasound instrument with transcutaneous delivery could be of use in applications such as creation of myocardial lesions, peripheral vessel thrombolysis, and drug and gene delivery. Adjunct administration of microbubbles has been found to enhance thrombolysis, and drug and gene therapy. Ongoing studies strongly suggest that therapeutic ultrasound could have an important role in cardiovascular disorders associated with thrombosis, inflammation, atherosclerotic disease, and arrhythmias.     

Ultrasound techniques in the evaluation of the mediastinum,part I: endoscopic ultrasound (EUS), endobronchial ultrasound (EBUS) and transcutaneous mediastinal ultrasound (TMUS), introduction into ultrasound techniques

Ultrasound imaging has gained importance in pulmonary medicine over the last decades including conventional transcutaneous ultrasound (TUS), endoscopic ultrasound (EUS), and endobronchial ultrasound (EBUS). Mediastinal lymph node staging affects the management of patients with both operable and inoperable lung cancer (e.g., surgery vs. combined chemoradiation therapy). Tissue sampling is often indicated for accurate nodal staging. Recent international lung cancer staging guidelines clearly state that endosonography (EUS and EBUS) should be the initial tissue sampling test over surgical staging. Mediastinal nodes can be sampled from the airways [EBUS combined with transbronchial needle aspiration (EBUS-TBNA)] or the esophagus [EUS fine needle aspiration (EUS-FNA)]. EBUS and EUS have a complementary diagnostic yield and in combination virtually all mediastinal lymph nodes can be biopsied. Additionally endosonography has an excellent yield in assessing granulomas in patients suspected of sarcoidosis. The aim of this review, in two integrative parts, is to discuss the current role and future perspectives of all ultrasound techniques available for the evaluation of mediastinal lymphadenopathy and mediastinal staging of lung cancer. A specific emphasis will be on learning mediastinal endosonography. Part I is dealing with an introduction into ultrasound techniques, mediastinal lymph node anatomy and diagnostic reach of ultrasound techniques and part II with the clinical work up of neoplastic and inflammatory mediastinal lymphadenopathy using ultrasound techniques and how to learn mediastinal endosonography.     

Therapeutic ultrasound applications in craniofacial growth, healing and tissue engineering

Previous reports have shown that therapeutic ultrasound enhances healing of fractured bone as well as cut tendons. Moreover, it has been shown that therapeutic ultrasound enhances bone formation during distraction osteogenesis that is also known as Ilizarove technique. It has been recently reported that therapeutic ultrasound enhances tooth formation and eruption during mandible distraction osteogenesis in rabbits. This enhanced tooth formation and eruption was caused by new dental tissue formation, known as dentin and cementum. This led to a clinical trial in human that showed that therapeutic ultrasound can enhance repairing tooth root resorption caused by orthodontic treatment. This discovery can lead to many applications of ultrasound in the dental as well as in the craniofacial reconstructions. This paper provides an overview of the molecular basis of the achieved clinical results. Moreover, potential future application will be elaborated.     

Revisiting heart activation-conduction physiology,part I: atria

This discussion paper re-examines the conduction-activation of the atria, based on observations, with respect to the complexity of the heart as an organ with a brain, and its evolution from a peristaltic tube. The atria do not require a specialized conduction system because they use the subendocardial layer to produce centripetal transmural activation fronts, regardless of the anatomical and histological organization of the transmural atrial wall. This has been described as “two-layer” physiology which provides robust transmission of activation from the sinus to the AV node via a centripetal transmural activation front. New productive insights can come from re-examining the physiology, not only during sinus rhythm but also during atrial tachycardias, in particular atrial flutter and atrial fibrillation (AF). During common flutter, the areas of slow conduction, in the isthmus and following trabeculations, particularly the subendocardial layer confines conduction through the trabeculations which supports re-entry. During experimental or postoperative flutter, the circular 2D activation around the obstacle follows the physiological transmural activation. Understanding this physiology offers insights into AF. During acute or protracted AF, the presence of stationary or drifting rotors is characteristic and consistent with normal physiological 2D atrial activation, suggesting that suppressing physiological transmural activation of AF will permanently restore normal sinus node atrial activation. In contrast, during permanent AF, normal 2D activation is abolished; the presence of transmural, serpentine, and chaotic atrial activation suggests that the normal physiological activation pattern has been replaced by a new, irreversible variety of atrial conduction that is a new physiology, which is consistent with evolution of complex systems.     

Therapeutic ultrasound in soft tissue lesions.

Therapeutic ultrasound is one of the most common treatments used in the management of soft tissue lesions, which constitute the majority of rheumatic complaints. Although many laboratory-based research studies have demonstrated a number of physiological effects of ultrasound upon living tissue, there is remarkably little evidence for benefit in the treatment of soft tissue injuries. This may be related to several confounding factors, including technical variables, the complexity and variety of underlying pathologies in soft tissue lesions, methodological limitations of clinical studies, or true lack of effect. In this review the scientific basis for the use of therapeutic ultrasound in soft tissue lesions and the existing evidence relating to its clinical effect are detailed.     

Triage in medicine, part I: Concept, history, and types

This 2-article series offers a conceptual, historical, and moral analysis of the practice of triage. Part I distinguishes triage from related concepts, reviews the evolution of triage principles and practices, and describes the settings in which triage is commonly practiced. Part II identifies and examines the moral values and principles underlying the practice of triage.     

动脉粥样硬化狭窄的血管内超声消融疗效

目的:探讨动脉粥样硬化(AS)斑块的血管内超声消融价值。方法:30例冠状动脉AS患者被前瞻性随机分为血管内超声消融组(A组,15例)和单纯PTCA组(B组,15例)。回顾性分析前述两组及9例经血管内超声消融的外周AS患者的疗效。结果:A组经单纯冠脉内超声消融治疗后狭窄程度由(84.1±4.7)％降为(43.0±15.5)％(P<0.05),无1例并发症,但其残余狭窄(43.0±15.5)％仍显著高于B组(P<0.01),B组在PTCA术后残余狭窄为20.9±2.9％。9例外周AS者经单纯血管内超声消融后,平均狭窄程度也由术前的(87.8±7.6)％降为(41.2±9.4)％(P<0.05)。结论:血管内低频高能超声消融术是动脉粥样硬化斑块的一种新的、有效治疗手段。