title: [Evaluation of the experience of the observer in the interpretation of myocardial scintillography with radioactive phosphates].
abstract: Two-hundred-and five myocardial scans with radioactive phosphates, performed in 185 patients interned at the Coronary Care Unit due to acute chest pain (147 myocardial infarcts: 58 coronary heart disease), were independently interpreted by six observers with different degrees of experience on the lectures of these kind of images (two nuclear physicians, two cardiologists, and two fellows of the Nuclear Medicine Unit). A series of six different grades of myocardial concentration of the radioactive phosphates, related to its osseous concentration were followed. Each observer reported the grade of concentration he found in each image. The fraction of myocardial infarcts and of coronary heart disease found by each observer in every grade of concentration were calculated. With these data, it was determined the optimal criterion level of each observer by which he attained the minor incidence of false negative and false positive results. Four observers found their optimal criterion level on 2F, where grades 0-2D are considered as negative, and grades 2F-4 are considered as positive. One observer found his optimal level at 2D (0-1: -; 2D-4: +) and other at 1 (0: -; 1-4: +. By using a decision matrix which relates results of the test with a binary outcome (normal, abnormal) to the actual diagnosis, also with a binary outcome (infarct, no infarct), the ratios for "sensitivity", "specificity" and "accuracy" were derived for each observer performing at his particular optimal criterion level. Our results suggests that the observer performance depends on his particular degree of experience in interpreting nuclear medical images and on his visual perception. It was concluded that it is necessary to periodically evaluate the individual optimal criterion level of the physicians in charge of the lectures of the myocardial images with radioactive phosphates, liable to shift with time in relation to the experience of the observer. The need of a more objective procedure to quantitate myocardial concentration of the radioactive phosphates is also implied.
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D010710:Phosphates; D011877:Radionuclide Imaging; D013667:Technetium
chemical_list: D010710:Phosphates; D013667:Technetium
vernacular_title: Valoración de la experiencia del observador en la interpretación de la centelleografía del miocardio con fosfatos radiactivos.