Secure transmission of urologic images and records over the Internet

Purpose: Telemedicine has become a common method for the transmission of im ages and patient data across long distances. Our goal was to assess the eff iciency and accuracy of Photomailer MD(TM) software, a store-and-forward te lemedicine system, in the urologic setting. Methods: Photomailer MD software was loaded on two computers in the host in stitution, one with a T1 connection to the Internet and the other with a di al-up modem connection (24,000 bits/second), and computers at three remote sites. A total of 14 clinical cases, comprised of digitized histories and r adiographic images, were sent to the remote institutions four separate time s using the four transmission modes available: nonencrypted, 56-bit encrypt ion, 128-bit encryption, and 128-bit encryption with password. The followin g data points were recorded: file size before and after encryption, file tr ansmission times, and diagnostic accuracy of the remote urologists. One-way ANOVA was used to compare mean values statistically, while the z-test was used to compare diagnostic accuracies. Results: Encryption increased the file size by a mean of 37.8%, with the th ree encryption modes increasing file sizes by the same number of kilobytes. When a dial-up modem was used, encrypted files required a significantly lo nger transmission time (P < 0.05) than the unencrypted files. The same tren d was seen with the T1 connection, although the differences often mere not significant. When T1 transmission times were compared with modem times with other variables held constant, modem times were significantly longer (P < 0.05), Diagnostic accuracies for each of the three remote centers ranged fr om 85.7% to 100%. Differences in accuracy rates between attending physician s and residents were not significant. Conclusions: Photomailer MD provides a secure, convenient, and affordable m ethod of transmitting patient images and records via the Internet, Transmis sion speed was significantly greater when using a T1 line and also tended t o be faster when files were not encrypted, There was no significant differe nce in transmission time among the three encryption modes; therefore, 128-b it encryption with a password should be used to maximize security. Diagnost ic accuracies were comparable to those in the literature. In general, 640 x 480-pixel resolution was adequate for urologic diagnoses, although higher- resolution images may improve accuracy.