Assessment of the quality of neonatal echocardiographic images transmittedby ISDN telephone lines

Objective-To assess the quality of echocardiographic images from neonates t ransmitted over Integrated Service Digital Network 2 (ISDN2) channels. Design-Echocardiographic images were viewed live in real time either by a d irect video link or by transmission over the commercial network, using one, two, or three ISDN2 channels. The order of the viewing formats was random and four observers marked each view for potential for provision of complete diagnostic information and quality. Setting-Cardiology department of tertiary referral centre for paediatric ca rdiac services. ISDN Lines were positioned in two nearby rooms. Telephone c onnection was through the commercial network and video connection by a dire ct video cable. Patients-10 neonates were studied (weight 2600 to 3900 g). In each, nine ec hocardiographic studies were undertaken to assess imaging (M mode and cross sectional) and Doppler (spectral and colour) quality. Results-No significant differences were found in diagnostic ability between the different formats for ICI mode, colour, or spectral Doppler studies. F or cross sectional imaging the diagnostic information and image quality inc reased with increasing numbers of ISDN channels. With six channels there wa s little difference from the directly connected images. Conclusions-In echocardiographic assessment of the newborn, one or two ISDN 2 channels will transmit images of satisfactory quality in many situations but three or more channels are necessary to ensure minimum degradation of t he Live image.