Search results for "ULTRASOUND"

Sonoporation, a redefined ultrasound modality as therapeutic aid: a review.

2011

Traditionally a diagnostic modality, ultrasound is emerging as a promising tool for non-invasive therapy, drug delivery, and gene therapy. The ultrasound is a mechanical wave energy generated in a medium as oscillating pressure in space and time at frequencies above 20 kHz, beyond the audible range. The ultrasound exposure generates bioeffects resulting in tissue heating, shear stress, and cavitation, which have been exploited for therapeutic applications. Ultrasound cavitation, enhanced by injected micro bubbles, perturbs cell membrane structures to cause sonoporation and increases the permeability to bioactive materials. Ultrasound-mediated gene delivery has been applied to heart, blood v…

2017

Background Catheter-based lysis with recombinant tissue plasminogen activator (rtPA) is a well-established therapy for spontaneous intracerebral hemorrhage (ICH). The effectiveness of this therapy can be increased with ultrasound, but the optimal conditions are not yet clearly established. Using a novel in vitro system of blood clots previously developed by our group, we investigated various parameters of intralesional sonothrombolysis using an endosonography catheter in combination with rtPA. Methods Standardized human blood clots were equipped with a drainage catheter and weighed before and after 4 treatments: control (drainage only), rtPA only, ultrasound only and the combination of rtPA…

Ultrasound-based testing of tendon mechanical properties: a critical evaluation.

2015

In the past 20 years, the use of ultrasound-based methods has become a standard approach to measure tendon mechanical properties in vivo. Yet the multitude of methodological approaches adopted by various research groups probably contribute to the large variability of reported values. The technique of obtaining and relating tendon deformation to tensile force in vivo has been applied differently, depending on practical constraints or scientific points of view. Divergence can be seen in 1) methodological considerations, such as the choice of anatomical features to scan and to track, force measurements, or signal synchronization; and 2) in physiological considerations related to the viscoelas…

Bioeffects of ultrasound: an experimental study on human embryos.

1991

Abstract The foetuses of 10 women at 9–12 weeks gestation were irradiated with ultrasound under typical diagnostic exposure conditions immediately prior to abortion. Electron microscopy of liver fragments revealed neither morphological nor structural changes.

Ultrasonic demonstration of small pancreatic islet cell tumors.

1982

In three patients real-time sonography successfully localized small pancreatic islet cell tumors measuring 7, 8, and 17 mm in size. Ultrasound is suggested as the initial radiologic examination for localization of endocrine pancreatic tumors. If ultrasound is negative or equivocal, computerized tomography, arteriography, and pancreatic venous sampling are indicated.

Is the stripping technique a tissue-sparing procedure in large simple ovariancysts in children?

2008

Abstract Background Stripping of the cystic wall is performed by gynecologists to treat large ovarian cysts. Information in the pediatric population is poor. We prospectively evaluated the pathologic specimens of large ovarian cyst to determine whether the stripping technique is a tissue-sparing procedure even in this age. Methods We evaluated 5 patients. Samples were taken from the intermediate part of the cystic wall and from the layer covering the cyst during excision. The presence of ovarian tissue adjacent to the cyst wall, and the morphological features of the surrounding tissue were both evaluated. Pelvic ultrasound follow-up was also performed. Results Patients' mean age was 4.5 yea…

Angiogenesis of cancer of the cervix. Contrast-enhanced dynamic MRT, histological quantification of capillary density and lymph system infiltration

1998

Purpose: It was the aim of this project to examine (i) the relationships between contrast-enhanced dynamic MR imaging derived characteristics and histologic microvessel density counts – a recognized surrogate of tumor angiogenesis – from tumors in patients with primary or recurrent cancer of the uterine cervix, and (ii) to correlate these parameters with lymphatic involvement (i. e. lymphatic channels) to assess tumorbiological aggressiveness in terms of lymphatic spread. Materials and methods: Pharmacokinetic MR imaging parameters (amplitude A, exchange rate constant k 21) were derived from contrast-enhanced dynamic MR imaging in thirty-three patients with biopsy proven cancer of the uteri…

Congenital Pediatric Diseases

2008

Major congenital malformations are diagnosed in 4%–6% of all infants and fetuses (Lynberg and Edmonds 1992). About one third of them are the leading cause for infant mortality or morbidity (Grandjean et al. 1999). Malformations of the internal urogenital system are diagnosed in about 1% of all infants and account for approximately 20% of all congenital malformations, thus being one of the three most frequent birth defects (Table 11.1.1). Therefore a pre- and/or postnatally performed ultrasound screening for malformations of the internal urogenital system should be part of the routine to reduce perinatal mortality and morbidity. The reliability and value of ultrasonographic screening for con…

Antenatal Ultrasound Diagnosis of Congenital Malformations of the Urinary Tract: Results and Criticism

1986

From October 1979 to June 1983 220 malformations were diagnosed antenatally at our hospital; 55 (25%) were malformations of the urinary tract, 21 of them hydronephroses and 34 of them dysplasias.

Determination of thyroid volume in infants with suspected congenital hypothyroidism—the limitations of both subjective and objective evaluation

2020

Objective: To compare two methods of assessing gland size on thyroid ultrasound in newborn infants with suspected congenital hypothyroidism (CH). Methods: Images from infants with eutopic glands referred between 2007 and 2013 were evaluated blind by two sets of observers. Subjective gland size was categorised as small, borderline-small, normal, borderline-large and large. Objective gland volume, calculated as the sum of each lobe using the prolate ellipsoid formula (length x width x depth x π/6), was put into corresponding categories: <0.8, 0.81–1.0, 1.1– <2.2, 2.2–2.4 and >2.4 ml, derived from normative Scottish data. Results: Of 36 infants, permanent CH was present in 17, transie…