Influence of postprocessing curves on contrast-echographic imaging: preliminary studies.

The aim of this study was to evaluate the influence of postprocessing curves on the visual and quantitative enhancement of image brightness caused by the injection of a contrast agent. A fixed dose (0.45 ml/kg) of contrast agent EchoGen was injected into three dogs, and images of the kidney were investigated using one linear (A) and three nonlinear (B, C, D) postprocessing curves. Curve D gave the best gray scale images and was generally used for diagnostic imaging. Images were analyzed qualitatively in three dogs and quantitatively in one dog for brightness change caused by contrast agent injection. Visually the changes were most identifiable with curve C and least by curve D. Video intensity time curves reflected the qualitative changes. Peak contrast and area under the video density curve changed in the order curve D < curve B approximately curve A < curve C. Choice of the postprocessing curve can have a marked influence on the enhancement of image brightness by a contrast agent. Postprocessing curves optimized to display a wide range of echo levels may not always be an ideal choice for contrast sonography.