Minimum requirements for remote realtime fetal tele-utrasound consultation

We studied the transmission bandwidth required for accurate diagnoses when performing realtime fetal tele-ultrasound consultations. The study was divi ded into three phases. In phase I, three experienced clinicians evaluated t he quality of ultrasound images transmitted at various bandwidths (internal ly looped back within Brisbane) using eight commercially available codecs a t random. The two codecs that performed best proceeded to phase 2, in which a realtime video-link of: up to 2 Mbit/s was set up between Brisbane and T ownsville (1500 km apart). Testing with a standard video-tape was performed at seven different bandwidths selected at random, with four clinicians (wh o were blinded to the equipment and bandwidths used). The optimum line rate s for transmission were determined, and testing was then performed using th ese line rates for fetuses with various anomalies (phase 3). The results:sh owed significant differences in performance according to bandwidths used, b ut not according to observers. Bandwidths were grouped into three levels. A t level I (256 kbit/s) the performance was significantly worse than at leve l II (384, 512 or 768 kbit/s), which was in turn worse than that at level I II (1, 1.5 or 2 Mbit/s). However, within each level, performance at one ban dwidth was not significantly different from that at the others. The most co st-effective transmission rates therefore appeared to be 384 kbit/s and 1 M bit/s. Further testing With fetuses affected by various anomalies confirmed that the majority could be diagnosed using a 384 kbit/s link, with slight improvement in evaluation when the bandwidth was increased to 1 Mbit/s.