The effect of resolution, compression, colour depth and display modality on the accuracy of accident and emergency telemedicine

There are no current recommendations regarding the minimum technical specif ication for realtime telemedicine consultation in accident and emergency (A &E) practice. We assessed the effect of image resolution, compression, colo ur depth and display modality on perceived image quality and telediagnosis. Test sets of digitized radiographs and clinical images were subjected to a series of standardized manipulations and the resulting output files were e valuated by an expert panel using image scoring and receiver operating char acteristic (ROC) analysis. For telemedicine in A&E work, the minimum techni cal specification should be regarded as images containing at least 250,000 pixels, compressed at up to JPEG 50 (or GIF for colour images) and displaye d on a high-resolution computer monitor. These specifications resulted in a verage file sizes of 17 kByte for digital images and 9 kByte for radiograph s.