University of Iowa Hospitals and Clinics: Department of Radiology: Teleradiology
The performance specifications for a teleradiology receiving station can be grouped into 4 broad categories: 1) modem 2) computer hardware (including hard disk storage) 3) image enhancement software and 4) TV monitor(s).
1. Modem
The modem's maximum speed (baud rate) influences the data
transmission time of the teleradiology sending station. To maintain
maximum transmission speed, the receiving unit must be equipped with
a modem of equal or greater maximum speed as the sending station.
2. Computer Hardware
Most teleradiology vendors use a DOS or Macintosh computer
platform. The specification parameters for teleradiology applications
are the same as for general computing applications. Minimally,
teleradiology systems should have:
The computer hard disk is used to store the received images. Disk drives are specified in megabytes (MB) of storage capability. To calculate disk capacity requirements, one determines the maximum number of images that are going to be stored at any one time. Based on the matrix size of the images the vendor will be able to determine the appropriate disk size.
A WORD OF CAUTION: Teleradiology systems store data in either a noncompressed or compressed format (see previous discussion about compression). Make sure your disk is large enough to store the maximum number of images you need in the noncompressed mod e. A general rule of thumb is that the hard disk should be at least 120 MB but the bigger the better.
3. Image Enhancement Software
Most teleradiology systems have gray scale window/level and
magnification image enhancement software. These should be included in
any teleradiology system considered for purchase. Other software
enhancement features that may be included are color, gray -scale
mapping, positive-negative reversal, annotation, minification, edge
enhancement, image flip/rotate, cine and histogram equalization. The
value of these additional software enhancements is subjective, and
largely dependent upon the types of images viewed and the preference
of the radiologists using the review station.
TV Monitors: The most common specifications stated for teleradiology TV monitors are monitor resolution and screen size. Resolutions range from about 512 by 512 pixels to 2048 by 2048 pixels. It is generally recommended that for teleradiology applications, monitors have a pixel resolution of 1000 by 1000 or above. Monitor screen sizes generally range from 14 to 21 inches. The larger monitors provide a better viewing environment.
Two other monitor specifications might be considered when purchasing a teleradiology system:
Split screen capability is a feature which allows the display of two or more different images on the monitor at the same time. This feature is important if two images need to be compared by the radiologist.
Monitor brightness is the specification for the maximum intensity of white light that a CRT can display. It is usually given in footlambert. This information is seldom given in vendor specifications, but is important when comparing teleradiology viewing stations. The brighter monitors (with high footlamberts) are better for viewing because the brightness differential between the shades is greater and thus easier for the human eye to detect.
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