PubMed · 803724
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J E Hoopes. 1975. Malignant-benign lesions: unsolved problems.. https://pubmed.ncbi.nlm.nih.gov/803724/
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Transesophageal echocardiography has been described as a useful tool in the diagnosis of pulmonary arteriovenous malformations. We describe a case in which intraoperative transesophageal echocardiography was used to aid localization and ensure complete surgical ligation.
OBJECTIVE: Branch retinal vein occlusions (BRVOs) are known to occur most commonly in the vicinity of arteriovenous (A/V) crossings. The authors aimed to identify types of venous wall abnormalities in BRVO and document their position in relation to the A/V crossing. DESIGN: A retrospective review of the color photographs and fluorescein angiograms from the most recent 110 patients with first- or second-order BRVO was performed. MAIN OUTCOME MEASURES: The films were examined for the presence of angioarchitectural changes of specified type within one-quarter disk diameter of the A/V crossing involved in the BRVO. The specific changes noted were fluorescein leakage, presumed thrombi, and flow abnormalities, which were recorded along with their position in relation to the A/V crossing. RESULTS: Of the 110 patients diagnosed with BRVO, 59 had photography of satisfactory quality. Forty-one (70%) of these 59 patients had venous lesions, of which significantly more (chi-square -5.74, P < 0.02) were downstream (56%) than upstream (12%) from the A/V crossing. Thirty-two percent were upstream and downstream. Of the hemodynamic changes seen, 49% had late venous phase leakage of fluorescein, 85% had abnormal flow, and 7% had presumed thrombi. All thrombi seen were downstream. CONCLUSIONS: Venous lesions in the vicinity of the A/V crossing commonly are seen in BRVO, most of which occur downstream. This suggests that the venous narrowing at the crossing may induce downstream hemodynamic changes predisposing to endothelial damage and thrombus generation.
A method for the fully computerized determination and optimization of positions of target points and collimator sizes in convergent beam irradiation is presented. In conventional interactive trial and error methods, which are very time consuming, the treatment parameters are chosen according to the operator's experience and improved successively. This time is reduced significantly by the use of a computerized procedure. After the definition of target volume and organs at risk in the CT or MR scans, an initial configuration is created automatically. In the next step the target point positions and collimator diameters are optimized by the program. The aim of the optimization is to find a configuration for which a prescribed dose at the target surface is approximated as close as possible. At the same time dose peaks inside the target volume are minimized and organs at risk and tissue surrounding the target are spared. To enhance the speed of the optimization a fast method for approximate dose calculation in convergent beam irradiation is used. A possible application of the method for calculating the leaf positions when irradiating with a micromultileaf collimator is briefly discussed. The success of the procedure has been demonstrated for several clinical cases with up to six target points.