Una mirada a la seguridad del ultrasonido en ecotomografía obstétrica / A look at the safety of ultrasound in obstetric echotomography

Resumen Los índices térmico y mecánico son estimadores de riesgo fetal en una ecografía y se deben controlar sus valores minimizando la exposición. Comparamos los valores de los índices térmico y mecánico obtenidos en exámenes ecográficos obstétricos de pacientes gestantes, con el valor recomendado por la comunidad internacional. Se realizó la estimación de estos índices en 421 ecografías obstétricas en 2019. Los valores fueron comparados entre ellos y con el valor recomendado para cada índice y según el modo de visualización (B, Doppler color y Doppler espectral). Del total de la muestra, para el índice térmico en modo Doppler color un 0,24% superó el valor estándar recomendado y en modo Doppler espectral un 2,85%. Para el índice mecánico se sobrepasó el valor recomendado en modo B en un 11,16%, en un 8,08% en modo Doppler color y, por último, en un 0,48% para el modo Doppler espectral. Los índices mecánico y térmico en esta muestra de exámenes ecográficos obstétricos se encuentran en promedio bajo el valor de referencia. Sin embargo, existe un número importante de casos en que se superan las normas, lo que debe ser una voz de alerta para la comunidad médica.

Abstract The thermal and mechanical indices are the best estimators of fetal risk in an ultrasound and their values should be controlled in order to minimize exposure as much as possible. We compared the values of the thermal and mechanical indices obtained in obstetric ultrasound examinations of pregnant patients, with the value recommended by the international community. These indices were estimated in 421 obstetric ultrasounds during 2019. The estimated values were compared with each other and with the recommended value for each index and according to the display mode (B, color Doppler and spectral Doppler). Of the total sample, for the thermal index in color Doppler mode, 0.24% exceeded the recommended standard value and 2.85%. in spectral Doppler mode. For the mechanical index, the recommended value was exceeded in B mode by 11.16%, in 8.08% in color Doppler mode and, finally, by 0.48% for spectral Doppler mode. The mechanical and thermal indices in this sample of obstetric ultrasound examinations are on average below the reference value. However, there is a significant number of cases in which the standards are exceeded, which should be a warning to the medical community.

Correlation Between Prenatal Doppler Ultrasound Exposure Durations and Newborn Rabbit’s Body Weight

@# Doppler mode ultrasound is widely used in prenatal scanning and known to produce a higher acoustic output which later leads to higher heat energy conversion compared to other ultrasound modes. It has been reported that the use of Doppler imaging might increase the temperature of tissues, thus, when Doppler is used in combination with 2D ultrasound, the risks of bioeffects tend to increase more. It is also known that prolonged exposure to ultrasound during pregnancy can cause irreversible biological destructions to the fetus. Despite the benefits of using Doppler ultrasound, its potential adverse effects have received scant attention in the research literature. Therefore, this study aimed to examine a correlation between gestational stages (GS) and newborn rabbit’s body weight at different prenatal Doppler ultrasound exposure durations. Methods: Twelve pregnant New Zealand white rabbits (NZWR) were exposed once using three different Doppler ultrasound exposure durations (30, 60, 90 minutes exposure) at three different GSs (1st, 2nd, and 3rd GS). After delivery, the mean weights of the 62 newborns were statistically analysed. Results: Strong negative and positive correlation between newborn’s body weight at different GSs and Doppler ultrasound exposure durations with a significant result found in 60 minutes exposure (p = <0.01) and 90 minutes exposure (p = <0.01), respectively. Conclusion: It can be concluded that longer Doppler ultrasound exposure may lead to significant results onto the newborn rabbits’ body weight.

Experimental study of a novel phase change nanodroplets enhanced high intensity focused ultrasound ablation / 中国介入影像与治疗学

Objective To investigate the effect of lipid encapsulated 1,1,2-trichlorotrifluoroethane phase change nanodroplets for high intensity focused ultrasound (HIFU) ablation.Methods The lipid encapsulated 1,1,2-trichlorotrifluoroethane phase change nanodroplets was prepared with membrane hydration method,and its physicochemical properties were examined.The synergistic effect of HIFU ablation was verified with experiments in vitro and in vivo experiments.For in vitro experiment,the isolated bovine liver tissues were irradiated with HIFU (250 W,10 s,continuous wave).For in vivo experiment,the livers of New Zealand rabbits were irradiated with HIFU (200 W,5 s,continuous wave).The volume of coagulative necrosis,energy efficiency factors (EEF) and the volume of the hyperechoic area after HIFU radiation were measured.And the statistical analysis was performed.Results Phase change nanoparticles were spherical in solution and uniform in size.For in vitro experiment,the coagulative necrosis volume,EEF and hyperechoic area of bovine liver tissue injected with nanodroplets were significantly higher than those of untreated bovine liver tissue (t=28.80,19.55,14.30;P=0.01,0.02,0.02) after HIFU.For in vivo experiment,the coagulative necrosis volume,EEF and hyperechoic area of rabbit liver tissue injected with nanodroplets were significantly higher than those of untreated rabbit liver tissue (t=9.41,13.52,15.67;P=0.02,0.01,0.01) after HIFU.Conclusion The lipid encapsulated 1,1,2-trichlorotrifluoroethane phase change nanodroplets can significantly improve the efficiency of HIFU ablation significantly.

Seguridad del ultrasonido obstétrico para la salud de la embarazada y el feto / Safety of obstetric ultrasonography for maternal and fetal health

El ultrasonido diagnóstico ha creado polémicas desde sus inicios y el ultrasonido obstétrico no ha estado fuera de la discusión. Existe una variada opinión que va desde una total inocuidad del método, pasando por los que tienen una opinión reservada sobre el tema y los que refieren que es perjudicial para el feto. Conociendo que los tejidos absorben las ondas sonoras y estos a su vez se convierten en energía térmica, mientras más alta sea esta, más riesgos tiene el feto de que se le cause bioefectos. El riesgo aumenta cuando la gestante presenta fiebre. Por otro lado, el personal que realiza el examen tiene escaso conocimiento a nivel mundial respecto a la salida acústica de los equipos que usan, los bioefectos y la seguridad del ultrasonido en general. Debemos tener presente el principio que consiste en usar densidades de energía tan bajas como razonablemente sea posible, para alcanzar datos e imágenes útiles para llegar al diagnóstico. Los profesionales de la salud deben seguir las guías sobre el uso del ultrasonido obstétrico, para prevenir una exposición indiscriminada de ondas sonoras sobre la madre o el feto(AU)

Diagnostic ultrasonography has always been a controversial topic, and obstetric ultrasound has not been outside the debate. Many different criteria have been held about the subject: some state that the method is totally safe, while others have a reserved opinion, and still others refer to negative effects on the fetus. Because tissues absorb sound waves, turning them into thermal energy, the higher the energy the more risks there will be of bioeffects on the fetus. The risk increases when pregnant women have a fever. On the other hand, the personnel performing the test have scarce knowledge about the acoustic output of the equipment they use, as well as the bioeffects and the safety of ultrasound in general. This is a worldwide fact. We should be aware of the need to use the lowest energy density reasonably required to obtain data and images useful for diagnosis. Health professionals should comply with the guidelines on the use of obstetric ultrasound to prevent unnecessary exposure to sound waves by mothers and fetuses(AU)

Effect of endogenous electric field on ocular cell behaviors / 中华实验眼科杂志

Corneal epithelial cells,lens epithelial cells,and retinal pigment epithelium cells contain a vast array of ion channels and pumps.The selective permeability to different ions generates endogenous electric fields and currents in those tissues.Abnormalities in the endogenous electric fields may underlie many ocular diseases,for example chronic corneal ulcers,posterior capsule opacity after cataract surgery,and retinopathies.How the electric fields influence the tissues and cells and participate in the occurrence of the ocular diseases is a hotspot of research in this field.This article briefly reviewed the mechanism of how the endogenous electrical activities are generated,the responses of ocular cells to applied electric fields,potential intracellular signaling mechanisms and clinical implications.Further understanding of this aspect is likely to offer new insights into ocular diseases.

Ultra-som terapêutico na cicatrização tecidual / Therapeutic ultrasound in the tissue healing

Visando a minimizar o período de tratamento cicatricial em diversos tecidos, buscam-se alternativas à terapia convencional que colaborem com o processo reparativo criando um microambiente ideal para sua ocorrência. Dentre os inúmeros benefícios das técnicas aplicáveis à medicina regenerativa, o ultra-som terapêutico (UST) é prática adjuvante cada vez mais freqüente. Os modelos experimentais de terapia sonora em animais têm propiciado informações relevantes para o tratamento de vários tipos de lesões; todavia, apesar de serem muito utilizados, ainda existem controvérsias em relação aos seus potenciaia biológicos de acordo com a modalidade e a dosimetria indicadas para cada caso. Os efeitos biofísicos do ultra-som (US) sobre o reparo tecidual são pouco compreendidos, sendo seu uso muitas vezes negligenciado ou fundamentado na experiência prática, o que resulta em procedimentos errôneos. O objetivo desta revisão bibliográfica é apresentar informações sobre o UST, relatar a existência de riscos de danos celulares decorrentes da inadequada aplicação e revelar a importância de seus mecanismos de ação nos tecidos, tanto no sentido físico, como nos seus aspectos biológicos.

Aiming to minimize the cicatricial treatment period, alternatives have been searched to conventional therapy, among which the therapeutic ultrasound is a practice more and more frequent. However, despite of being used in the treatment of various lesions types, there are still controversies related to its real therapeutical value and the indicated dosimetry for each case. The ultrasound effect on the tissue repair is little understood, and its use is seldom based on the practical experience, what sometimes results in wrong procedures. This review has the objective to show the therapeutic ultrasound information and to reveal the importance of its mechanisms in the tissues in the physical and biological aspects.