排序方式: 共有41条查询结果,搜索用时 62 毫秒
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Valsangiacomo Büchel ER DiBernardo S Bauersfeld U Berger F 《The international journal of cardiovascular imaging》2005,21(2-3):313-322
Background: Catheter-guided interventions are increasingly used for relief of lesions in patients with congenital heart disease. Exact anatomical imaging with measurement of the vascular structures is crucial in the planning of such interventions. This can be provided non-invasively and without radiation by contrast-enhanced MR angiography (CE-MRA). Aim: To evaluate the accuracy of the measurements of the vessels obtained by CE-MRA in comparison to those obtained by conventional X-ray angiography (XRA). Methods: Measurements of the diameters of aorta and pulmonary arteries were performed retrospectively and blinded on the CE-MRA and XRA images, in comparable locations. The limits of agreement between the two methods were calculated. Results: Twenty-one CE-MRA and XRA were performed in 20 children with congenital heart disease, median age 4 years (1 day–13 years), weight 18 kg (3.2–74 kg). The time interval between CE-MRA and XRA was 2.6 ± 2.3 months. A total of 98 measurements, 38 of the aorta and 60 of the pulmonary arteries were performed on the images obtained by each technique. The correlation between CE-MRA and XRA measurements was excellent, r=0.97, p < 0.0001. The mean difference between the two techniques was 0.018 ± 1.1 mm; the limits of agreement –2.14 and + 2.18 mm. Similar agreement was found for measures of the aorta (r=0.97, mean difference 0.20 ± 1.08 mm) and of the pulmonary arteries (r=0.97, mean difference 0.048 ± 0.89 mm). Conclusions: CE-MRA provides accurate quantitative anatomical information, which highly agrees with XRA data, and can therefore be used for planning catheter-guided procedures. 相似文献
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Barry Edward DiBernardo Jennifer Reyes Bo Chen 《Journal of cosmetic and laser therapy》2013,15(2):62-69
Liposuction is a standard for removing fat. Recently developed, laser lipolysis can be used to simultaneously remove unwanted fat and tighten skin. Laser lipolysis is accomplished with single or multiple sequential wavelengths. Development of an optimal method requires detailed understanding of tissue heating for the wavelengths employed. This study systematically evaluates tissue heating for superficial and deep laser lipolysis using three approaches, and correlates temperature rise with histology changes, defining appropriate system parameters. Two individuals scheduled for abdominoplasty had laser testing on healthy abdominal skin scheduled for excision. Each treatment was applied to 3×3 cm squares with various laser parameters. Treatment was conducted in the fatty layer for lipolysis and subdermally for skin tightening. Individual squares were treated with SmartLipo (Cynosure, Inc. Westford, MA, USA) using 1064 nm, 1320 nm, or MultiPlex (1064 nm/1320 nm) with laser doses of 8.3 to 333 J/cm2. Exposures were applied at 3–5 mm or ~20 mm depth below the skin surface. Skin temperatures at the surface and at depths of 5 mm to 37 mm were recorded immediately post-treatment for each exposure. Treated tissue was excised and evaluated for thermal injury using H&E and transmission polarization microscopy. Histology was correlated to tissue temperature to determine appropriate treatment limits. Superficial treatment with surface temperatures exceeding 47°C (50°C and 55°C at 5 mm depth) typically caused epidermal and dermal injury, with blistering above 58°C. Below this threshold, focal collagen change and dermal inflammatory response were found in many samples without epidermal injury. These acute thermal effects may link to skin tightening during the healing process. Deep treatments, at up to 133 J/cm2, exhibited minimal temperature rise and induced thermal effects in vessels and ligaments. Higher laser doses were associated with a significant temperature increase. In conclusion, superficial subdermal heating (within approximately 5 mm of the surface) during laser lipolysis should limit skin surface temperature to 42°C. The laser dose per surface temperature rise in treatments are 4.5 J/cm2/°C for 1320 nm, 6 J/cm2/°C for MultiPlex and 7.5 J/cm2/°C for 1064 nm. Clinical studies should be performed to validate these results. 相似文献
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Prichard HL Manson RJ DiBernardo L Niklason LE Lawson JH Dahl SL 《Journal of cardiovascular translational research》2011,4(5):674-682
Intimal hyperplasia is one of the prominent failure mechanisms for arteriovenous fistulas and arteriovenous access grafts.
Human tissue-engineered vascular grafts (TEVGs) were implanted as arteriovenous grafts in a novel baboon model. Ultrasound
was used to monitor flow rates and vascular diameters throughout the study. Intimal hyperplasia in the outflow vein of TEVGs
was assessed at the anastomosis and at juxta-anastomotic regions via histological analysis, and was compared to intimal hyperplasia
with polytetrafluoroethylene (PTFE) grafts in the baboon model and in literature reports from other animal models. Less venous
intimal hyperplasia was observed in histological sections with arteriovenous TEVGs than with arteriovenous PTFE grafts. TEVGs
were associated with a mild, noninflammatory intimal hyperplasia. The extent of intimal tissue that formed with TEVG placement
correlated with the rate of blood flow through tissue engineered vascular grafts at 2 weeks postimplant. Outflow vein dilatation
was observed with increased flow rate. Both mid-graft flow rates and outflow vein diameters reached a plateau by week 4, which
suggested that venous remodeling and intimal hyperplasia largely occurred within the first 4 weeks of implant in the baboon
model. Given their compliant and noninflammatory nature, TEVGs appear resistant to triggers for venous intimal hyperplasia
that are common for PTFE arteriovenous grafts, including (1) abundant proinflammatory macrophage populations that are associated
with PTFE grafts and (2) compliance mismatch between PTFE grafts and the outflow vein. Our findings suggest that arteriovenous
TEVGs develop only a mild form of venous intimal hyperplasia, which results from the typical hemodynamic changes that are
associated with arteriovenous settings. 相似文献
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Kugler LJ DiBernardo C Margalit E 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》2006,41(1):41-43
CASE REPORT: We report a case that illustrates the effectiveness of optical coherence tomography (OCT) in identifying visually significant vitreoretinal interface opacities in the absence of a macular hole. A patient presented with a scotoma in the right eye. Fundoscopic examination revealed a small lesion in close proximity to the foveal avascular zone. OCT of the right eye revealed a small operculum in the vitreous anterior to the fovea without evidence of a macular hole. COMMENTS: To our knowledge, ours is the first reported case of the use of OCT to identify the presence of a visually significant operculum without an associated macular hole. 相似文献
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