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Sources of Ultrasonic Exposure
Published in Marvin C. Ziskin, Peter A. Lewin, Ultrasonic Exposimetry, 2020
Each application of ultrasonic waves in medicine has been developed to meet a specific medical need such as imaging internal soft tissues or depositing ultrasonic energy in targeted tissue structures for therapeutic or surgical purposes. There are three main sources of tissue ultrasonic exposure: (1) ultrasonic waves deposited in tissues from external devices, (2) modification of these waves by internal tissue structures, and (3) further interaction of tissue-modified waves (or products of the waves) and subsequently deposited waves from the external device. Consideration of the spatial and temporal characteristics of this exposure will determine the locally deposited energy and pressure magnitudes which are important parameters because the two suspected mechanisms for tissue bioeffects are ultrasonic heating and cavitation. The probability of ultrasound bioeffects is related also to the specific tissue insonated and the insonation volume.
Obstetric Outcomes after Recurrent Pregnancy Loss
Published in Howard J.A. Carp, Recurrent Pregnancy Loss, 2020
Rakefet Yoeli-Ullman, Howard J.A. Carp, Shali Mazaki-Tovi
The data regarding the association between RPL and congenital anomalies are scarce. Thom et al. [8] examined the Washington State birth certificate records and included 638 women with three or more miscarriages and a control group of women with no prior miscarriages (n = 3099). Women with RPL had a higher risk of delivering a child with congenital malformations (RR 1.8; 95% CI 1.1–3.0). The Recurrent Miscarriage Immunotherapy Trialists Group trial [44] showed an anomaly rate of 4%, which is higher than expected in the general population. Schoenbaum et al. [45] reviewed 5003 records of consecutive deliveries in 1975 and 1976 at the Boston Hospital for Women and analyzed singleton deliveries at 27 weeks’ gestation or greater. They compared women with exactly one prior proximate induced or spontaneous abortion with women of similar gravidity or parity with no prior pregnancy losses. The offspring of women with a proximate miscarriage had an increased incidence of congenital malformations. Finally, there are a few case reports reporting that chromosomal aberrations lead to both RPL and fetal anomalies [46]. Today, with the advances in ultrasonic detection of fetal malformations, many patients elect to terminate the pregnancy. Consequently, today the incidence of anomalies at birth may not be higher than in the general population.
Ultrasound and Microwave Hyperthermia in the Treatment of Superficial Human Cancerous Tumors
Published in Leopold J. Anghileri, Jacques Robert, Hyperthermia in Cancer Treatment, 2019
C. Marchal, P. Bey, S. Hoffstetter, J. Robert
Ultrasonic waves are mechanical vibrations in the frequency range above 20 kHz which combine appropriate penetration in human tissues with the ability to establish directive radiation beams. Such radiation-like behavior becomes increasingly pronounced at higher ultrasonic frequencies, where wavelengths become increasingly small relative to the dimensions of the structure through which the vibrations are propagated.239,240
Three-dimensional ultrasound VOCAL combined with contrast-enhanced ultrasound: an alternative to contrast-enhanced magnetic resonance imaging for evaluating ablation of benign uterine lesions
Published in International Journal of Hyperthermia, 2022
Jiantang Zhang, Guorong Lyu, Jincheng Qiu, Shaohua Qiu, Zuolin Li, Min Lin, Xiaoqing Xiao, Langlang Tang, Jinghua He, Xiaolian Li, Shuiping Li
The results of this study show that for both AM and UM, the agreement between 2D-CEUS and 3D-CEMRI is lower than that between 3D-VOCAL and 3D-CEMRI. However, the three methods showed no significant differences in NPV measurements of UM (p > 0.05). One possible explanation for this is that the NPV profile after UM ablation shows a clear boundary and an almost spherical or oval shape (Figures 1(A,B) and 2(A–C)). Therefore, the calculated volume was close to the actual volume. However, 2D-CEUS and 3D-CEMRI showed significant differences in the NPV measurement of AM (p < 0.05), which may be due to the absence of a capsule and unclear boundary of AM, resulting in an irregular NPV contour after ablation (Figures 1(C,D) and 2(D–F)). 2D-US measurements were only obtained in two vertical planes, and the calculation of volume by the elliptical volume formula can cause large errors. The 3D-US method has been found to be more accurate than the two-dimensional ultrasonic method for volume measurement of irregularly shaped objects [29].
Autoantibodies in association with subchorionic haematoma in early pregnancy
Published in Annals of Medicine, 2021
Yang Li, Ensheng Wang, Shisi Huang, Changling Zhu, Kemei Zhang, Jiaou Zhang, Haiyan Xu, Jing Shu
Tremendous improvement in medical ultrasonics lead to more precise diagnosis in obstetrics and gynaecology, with more subtle abnormalities being found. Subchorionic haematoma (SCH) is increasingly commonly observed in early pregnancy period, especially in women with vaginal bleeding. The incidence has been reported to be from 0.46% to 39.5% [1,2], depending on the populations studied and gestational age at diagnosis. The appearance of SCH on ultrasonic image is usually manifested as hypoechoic or anechoic crescent-shaped area (Figure 1). They are thought to result from partial detachment of the chorionic membrane from the uterine wall [3]. However, the exact aetiology is uncertain, and the clinical significance of SCH is controversial. On the other hand, numerous studies on reproductive failure focus on the dysregulation of maternal immune responses and thrombophilic causes [4,5]. It is possible that the occurrence of SCH is related to the imbalance of maternal-foetal immune interaction, leading to decidual immune vasculitis, intravascular microthrombosis, rupture of the decidua vessels, abnormal trophoblastic invasion, and ischaemia reperfusion followed by haemorrhage. Tuuli et al. proposed that shallow trophoblast invasion and impaired angiogenesis with resultant friable blood vessels may predispose to subchorionic haemorrhage as well as adverse outcomes [6]. The aim of the present study was to explore the possible aetiology of SCH, especially its association with autoantibodies, as well as the pregnancy outcomes of SCH patients.
Cell-derived biomimetic nanocarriers for targeted cancer therapy: cell membranes and extracellular vesicles
Published in Drug Delivery, 2021
Aixue Li, Yunan Zhao, Yixiu Li, Liangdi Jiang, Yongwei Gu, Jiyong Liu
The membrane is wrapped around the core through various methods, all with the ultimate goals of maintaining the membrane in the right direction and exposing the proteins on the membrane for communication. Shell-core fusion was first performed using a physical extrusion method that extends from the preparation of liposomes. The extrusion force can destroy the membrane structure and cause it to reform around NPs (Hu et al., 2015). Ultrasonic treatment is also a feasible method. The breaking force generated by ultrasonic energy can cause the cell membrane to spontaneously reshape on NPs (Copp et al., 2014). Ultrasonic treatment exerts the same effect as physical extrusion, but it results in less raw material loss and is easier to expand to the production scale, suggesting that the application prospects are brighter. The semistable characteristics of the membrane and the core, as well as the asymmetry of the charge on the surface of the membrane, help the membrane wrap the nanocore. The special right-side-out membrane orientation makes the combination of the two extremely thermodynamically stable.