Microbubbles in therapeutic ultrasound

Microbubbles in therapeutic ultrasound

S48 Ultrasound in Medicine & Biology Single ventricle: Diagnosis and prognosis Joanna Dangel Department of Perinatal Cardiology and Congenital Anoma...

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S48

Ultrasound in Medicine & Biology

Single ventricle: Diagnosis and prognosis Joanna Dangel Department of Perinatal Cardiology and Congenital Anomalies, Centre of Postgraduate Medical Education, Warsaw, Poland Between October 2011 and June 2019 we detected 2787 new heart defects in fetuses in the Referral Centre for Perinatal Cardiology in Warsaw, Poland, Agatowa US Clinic. 393 had univentricular hearts and 144 critical aortic stenosis. The term: SINGLE VENTRICLE is a very wide definition. If the heart is “functionally univentricular” one ventricle is too small or its function is too poor to maintain systemic or pulmonary cardiac output. It is already known that cardiac lesions are dynamic. It is likely that in some circumstances growth of cardiovascular structures depends on the volume of flow. There are hearts which will always be univentricular. There are: tricuspid atresia (67 cases), double inlet left ventricle (31), mitral atresia (9), hypoplastic left heart syndrome (222), and more complicated cardiac defects in which only one ventricle is developed. In such babies final treatment is to obtain Fontan circulation. During prenatal period it is important to plan the perinatal management and to decide what kind of treatment will be necessary in the newborns. Stenosis or hypoplasia of the pulmonary artery or aorta can occur, so the lesion will be ductal dependent. In other - restriction of the foramen ovale can cause the neonatal problem. In rare cases neonates will not need any treatment, if both arteries are well developed. On the other hand there are “evolving lesions”, like critical aortic stenosis (evolving HLHS) or pulmonary atresia and intact ventricular septum. In both we suspect that outflow tract obstructions caused underdevelopment of the ventricle. So fetal opening of the left or right outflow tract should be beneficial. Basing on this theory fetal cardiac interventional program developed. My team performed 90 aortic balloon valvluoplasties in 84 fetuses and 12 pulmonary artery valvuloplasties in 11 fetuses. In the recent period we achieved 48% of biventricular circulation of live born babies with critical aortic stenosis and 90% in pulmonary atresia or critical pulmonary stenosis. Criteria for prenatal intervention are still under development. The main rule is that prenatal cardiac interventions should be performed only if predictive outcome without intervention will be worse than without it. It must be remembered that fetal valvuloplasty in the aortic stenosis is the first step of long and complicated postnatal treatment. In conclusion: univentricular heart can be successfully treated for life long single ventricular physiology. In some lesions natural history can be changed by prenatal cardiac intervention.

Ventricular septal defects Paul Brooks Paediatric & Fetal Cardiologist, Melbourne Paediatric Cardiology & Western Health, Melbourne, VIC, Australia Ventricular septal defects (VSD’s) are the commonest structural congenital heart lesions. Isolated defects make up »1/3 of all congenital heart disease with VSD’s present in many other more complex lesions. Whilst antenatal diagnosis rate of isolated muscular defects continues to improve, a significant number of perimembranous and inlet defects are still missed. These defects, which are more difficult to identify on basic screening views, are more commonly associated with additional cardiac pathology, extracardiac and chromosomal abnormalities. This session will look at the various types of ventricular septal defects, including atrioventricular septal defects, from both a screening view and advanced fetal echo perspective. It aims to give insight into when and how to go beyond screening views for a more detailed look for VSD’s, and what features are important in counselling and ongoing management.

Volume 45, Number S1, 2019 SESSION 10G: EDUCATION The role and purpose of feedback in clinical practicethe current theory and practices Christina Johnson Director Monash Doctors Education, Consultant in General and Geriatric Medicine, Senior Lecturer, Faculty of Medicine, Nursing and Health Sciences, Monash University, Monash Health, Melbourne, VIC, Australia Feedback plays a critical role in quality training in clinical practice. But what are the ‘essential ingredients’ of quality feedback? This session will focus on clarifying the key building blocks of effective feedback, using evidence drawn from health professions, education, psychology and business literature.

Delivering feedback in clinical practice- the models which assist your clinical practice Christina Johnson Director Monash Doctors Education, Consultant in General and Geriatric Medicine, Senior Lecturer, Faculty of Medicine, Nursing and Health Sciences, Monash University, Monash Health, Melbourne, VIC, Australia Feedback offers great promise but most clinicians find it challenging in practice. This session will cover practical tips on quality feedback for clinicians, building on the evidence base for quality feedback, outlined in the previous session.

SESSION 10H: GENERAL ABDOMEN Microbubbles in therapeutic ultrasound J. Brian Fowlkes Departments of Radiology and Biomedical Engineering, University of Michigan, USA Microbubbles have been developed as ultrasound contrast agents as an emulsion of stabilized gas bubbles that can be injected systemically and circulate throughout the body. Contrast between vascular structures and other tissues is due to the high echogenicity of the bubbles and the significantly different nonlinear response of these bubbles compared to nonlinear signals due to finite amplitude distortion of the ultrasound field. Microbubbles can also be introduced as superheated perfluorocarbon droplets that when activated by ultrasound, vaporize to form gas bubbles in a process termed acoustic droplet vaporization (ADV). The droplets have a range of sizes depending on their purpose in diagnostic and therapeutic application. For therapy, such droplets can be used as vascular agents, can be extravascular such as for delivery in tumor tissue or even formulated into implantable constructs used in tissue engineering and used for spatial/temporal control of factors affecting incorporation of the construct. In each case, formulation can include encapsulate drugs for local release. When bubble are present in an ultrasound field, microbubbles can also affect tissue heating and can undergo stable and/or inertial cavitation resulting in physical effects to tissue ranging from petechial hemorrhage sites to complete cellular disruption. The latter is termed Histotripsy and has developed into an alternative treatment strategy to ultrasound therapies based on the heating of tissue. This presentation will discuss how microbubbles are being used in medical ultrasound and the advances being made in both diagnosis and therapy.