Hepatobiliary magnetic resonance contrast agents assessed by gadolinium-153 scintigraphy.

A simple method to test new gadolinium complexes potentially useful as enhancement agents for magnetic resonance imaging was developed. Healthy rats underwent scintigraphy with two potential hepatobiliary agents, diethyl IDA and diisopropyl IDA complexed with gadolinium-153. Control products included 153Gd DTPA, 153GdCl3 and technetium-99m diethyl IDA. As shown scintigraphically, 153Gd IDA complexes were partially excreted by urinary and hepatobiliary excretion early after administration. These findings paralleled significant reduction in 1H T1 values of excised livers. However, these agents exhibited prolonged 153Gd whole-body retention. The prolonged tissue distribution of 153Gd activity in animals given 153Gd diethyl IDA did not differ significantly from that observed in animals given GdCl3, and could be attributed to chemical instability or reticuloendothelial uptake. The scintigraphic method permits screening of gadolinium complexes in animals by showing mass balance, kinetics, distribution, and effective stability. Biologic effects of tracer or pharmacologic levels can be compared with those of carrier-free and carrier-added pharmaceuticals.

A method for training simulated patients.

The purpose of the study on which this article was based was to examine the effectiveness of training simulated patients with self-instructional materials. A six-hour program consisting of eight videotapes and 10 sets of written materials was administered to 54 trainees. Pretest and posttest score comparisons revealed an increase in knowledge about simulation. Most of the trainees (91 percent) stated that the simulation training program increased their competencies in portraying patients. Most important, simulators with the self-instructional training received higher ratings from trainers on their ability to evaluate students than did simulators in the control group.