In an experimental angioplasty study in dogs, we evaluated the characteristics of dilatation and deformation, as well as the pressure requirements, bursting points, and types of bursting of four different balloon dilatation catheters. The balloons, which were selected 0%, 30%, and 80-100% larger than the arterial lumen, measured 4, 6, and 8 mm in diameter and were inflated with an automated pump which simultaneously recorded balloon pressure and volume. Changes to the vessel wall were assessed radiographically and by histology. In vivo, balloon dilatation catheters demonstrated a markedly different behaviour than in vitro. Significantly higher pressures were tolerated due to the support of the arterial sleeve. Non-compliant oversized balloons caused more damage to the arterial wall than compliant ones. Oversized balloons attained their required diameters only with high inflation pressures of 10 to 12 atm or after rupture of the artery.
Ureteral obstruction is a serious complication in renal transplant recipients. The diagnosis may be difficult with standard methods of investigation, and definite treatment may, therefore, be delayed. This paper describes the indications, the technique, and the experience with antegrade pyelography, ureteral perfusion and percutaneous drainage in 18 patients with suspected urinary obstruction. Though invasive, these methods proved to be a safe, fast and accurate means for evaluating the location and significance of ureteral obstruction. For initial treatment in obstruction, percutaneous nephrostomy is the method of choice. Surgery should be delayed until recovery of renal function with decreasing serum creatinine is demonstrated. Patients with persistent or rising serum creatinine (greater than 250 mumol./l.) did not benefit from surgical relief of obstruction.
35 patients with scintigraphically silent thyroid regions without palpable cold nodules were further evaluated by ultrasonography. In 33 cases the sonographic diagnosis was confirmed by other examinations or the clinical course. 2 cases were misinterpreted right at the beginning of our series.The use of ultrasonography in evaluating silent thyroid regions in the totally decompensated autonomous adenoma, in unilateral thyroid aplasia, thyroiditis and hyperthyroidism is shown to be a reliable and valuable supplement to the clinical and radioisotopic evaluation procedures. When differentiating the totally decompensated autonomous adenoma from unilateral thyroid aplasia a stimulation test need not be performed in most cases. Suspected thyroiditis can be confirmed in a simple way. Being a non-invasive evaluation procedure, ultrasonography should be used before performing a needle biopsy.
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