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Digital cameras are reliable in teleradiology
  1. S Roychoudhury
  1. Specialist Registrar in Radiology, Guy’s and St Thomas’ Hospital NHS Trust, London, UK;

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Telemedicine, and particularly teleradiology, can be very useful in developing countries where skilled radiological expertise is not freely available. “Store and forward teleradiology”, where digitised images are electronically sent after image compression to reduce file sizes (for easier internet transfer), will be particularly useful. In this article the authors assess the adequacy of such a system using a freely available digital camera and various image compression algorithms.

Ninety one erect chest radiographs, most of which had one or more features of tuberculosis (consolidation, cavitation, effusion, pneumothorax, lymphadenopathy, calcification, scarring, etc), were photographed using a 5 megapixel Olympus 3000Z digital camera and were converted to gray scale and appropriately modified using Adobe Photoshop software. Twenty two radiographs were normal. Four blinded independent observers (three radiologists and one pulmunologist) read three versions of the same image: (1) the original analogue image, (2) the standard JPEG image (compressed to 400 MB), and (3) a JPEG 2000 image which involves 60:1 wavelet image compression (compressed to 120 MB). Software developed by the authors (available from helped in image viewing.

Receiver operating characteristic curve analysis of the data showed no significant difference between the interpretation of features of tuberculosis in the three groups apart from calcification which was better detected on the standard JPEG images than on the analogue images. This study shows that low cost, small file size teleradiology allows readings of sufficient quality to make a diagnosis of tuberculosis and can be of benefit to physicians in developing countries with slow dial-up internet connections.

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