EVALUATION OF COLOR IMAGES PRINTED BY A THERMAL DYE DIFFUSION PROCESS

Dry printing of medical images, without photochemicals, may be based o n the principle of thermal dye diffusion. The Drystar (Agfa Gevaert, M ortsel, Belgium) system was evaluated in colour-coded Doppler examinat ions of the carotid arteries. A total of 25 consecutive patients were examined for the colour test and 37 patients for the black-and-white t est. Colour and black-and-white data were available on the same view. The performances of the Drystar were tested against laser films, matri x films and two types of glossy paper using the following criteria: gr ey scale, colour scale, quality of reproduction of vascular colouring, registration, endothelial layer, intraluminal echogenicity, spectral resolution, and artefacts. The overall handiness of the document was g raded. A significant difference (p = 0.00005) was noted in favour of t he Drystar concerning registration, grey scale, spectral resolution an d vascular colouring. The global score for handiness of the colour fil m was 96%. Radiologists preferred the colour hard copy as compared wit h glossy paper prints. As in the black-and-white test, blue-base and c lear-base films obtained with the Drystar were rated inferior to laser films, a double line print mode was included in the printer, giving a density of 2.3 OD.