Evaluation of image processing and presentation methods in thallium-201 myocardial scintigraphy.

Using a phantom to simulate the LAO 45 degrees thallium-201 myocardial image with a transmural infarct of variable detectability, thirteen methods of computer image processing are evaluated for a group of eight observers using receiver operating characteristics (ROC curves). Initial results using electrostatic hardcopy images clearly demonstrate that images with three applications of a nine point smoothing routine and 30% background subtraction, displayed with three cycles of the grey scale, produce significantly more accurate interpretation (P less than 0.001) than the raw data, or any of the other methods used. This method provides an overall increase in the diagnostic sensitivity for the group and does not introduce a false positive bias. Grey scale cycling provides effective contrast enhancement as does a colour scale presentation. Comparing images as processed above with similarly smoothed images presented with a fifteen colour level scale on a TV monitor, the diagnostic sensitivities are not significantly different and this method provides the optimum image evaluation in this study.