A morphometric method to calculate liver volumes from transverse sections is evaluated (point-integrating method). In the first part of the study, 10 liver specimens were investigated by computed tomography (CT) and ultrasound (US); the calculated volumes were compared to the volumes obtained by water displacement of the organs. While CT showed an ideal agreement (r = 0.994), volumes calculated from US sections correlated less well (percentage differences from +12.5% to -9%, r = 0.915). In the second part of the study, the livers of 10 randomly selected patients were investigated by CT and US. Liver volumes were calculated using the point-integration method. Compared to the CT examination, US results show a good correlation with a correlation coefficient of r = 0.977. The point-integration method is very valuable to measure organ volumes from transverse sections. The method can be applied "offline" to photographic films, data do not have to be recorded electronically. The time required to calculate the volume of an organ is comparable to other methods.
Evaluation depends mostly on the demonstration of regional function (muscle movement, regional contraction volume, trend scintigram). A special technique permits the demonstration of insufficiency of the A-V valves and its approximate measurement. Comparison with single plane angiography showed good or excellent agreement concerning the ejection fraction (r = 0.86 for patients in sinus rhythm, 0.92 for patients without valvular disease). Inter observer error is very small (r = 0.99). These studies can be evaluated separately for the right and left ventricles (in an RAO 30 degrees projection).
We evaluated a bolus-chase technique designed to reduce the volume of contrast material and to shorten examination time during intravenous digital subtraction angiography (IV-DSA) of the lower limbs. With this technique, after a single injection of contrast material, two contiguous fields can be sequentially imaged (two-field DSA) using a step translated x-ray tube. 67 patients with peripheral vascular disease were studied. All examinations provided diagnostic information, so that in no instance additional intra-arterial injections were required. With the two-field DSA only 3.49 injections were needed in the average for five fields examined in each patient, resulting in a 30% reduction of contrast agent used.
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