Teleradiology is by far the most common telemedicine application. There are at least 10, and more likely 15 or more, diagnostic teleradiology cases for each interactive video patient-clinician consultation. Not only is there a lot of teleradiology activity, as shown in this issue’s review of teleradiology service providers; there is also a fair amount of money being spent on teleradiology equipment. A recent Frost & Sullivan estimate placed the 1996 world sales of teleradiology products at about $89 million. If PACS were considered in the equation, this figure would obviously be much higher.

To find out where the teleradiology industry is right now and what to expect for 1998, we surveyed the 52 vendors we consider to be leaders, by dint of market share or cutting-edge reputation. The survey was administered by phone, FAX, email, and via our Web-based questionnaire. We present here the responses we received.

This year’s big news is the development, at long last, of filmless direct digital imaging (DDI) technology. This is a full generation beyond the old "phosphor plate" direct acquisition technology used in (for example) CT scans. To explain this technology is beyond the scope of this article. However, you should start getting used to the words at the heart of this breakthrough: "amorphous silicon x-ray detectors". The DDI electronic plates cover the same area as a standard adult x-ray cassette (14" x 17"; to 41 cm x 41 cm), with a matrix of 2560 x 3072 elements each capable of 16-bit contrast and with a pixel pitch as low as 100 microns. This last feature is extremely important since it will probably allow these panels to be used for mammography, which has the technological requirement of being able to detect 100 micron microcalcifications (cf. Telemammography Feasibility, Vol. 4, no.6). The advantages of direct-to-digital image capture are obvious and numerous:

* elimination of film and processing chemicals
* no film-processing delays
* direct accession of images to PACS and teleradiology
* eliminates need for expensive film digitizers

Two companies have announced DDI products: GE Medical Systems and Sterling Diagnostic Imaging. Both have real products that have been undergoing extensive testing at university hospitals in the U.S. Their booths will likely be mobbed at RSNA. Neither company could commit to a price for their DDI product, nor to a specific availability time.

Other important trends:

* wavelets is becoming recognized as the best way to compress images with the least data loss. 10:1 compression can be attained, compared to the standard 3:1 for lossless JPEG compression (see Vol. 3, no. 2, p. 28). It is used in products from Access Radiology, EMED, and Sterling.

* Internet compatibility is increasingly a feature of teleradiology systems, enabling platform-independent transmission of images anywhere in the world. This is a feature of products from Acuson, Analogic, EMED, KLT’s ViewSend, Siemens, and ViTel Net.

* nearly every product is (or claims to be) DICOM 3.0 compliant. As Dave Swartz has emphasized in his TechTalk column (Introducing DICOM 3.0: A Standard for Medical Imaging; Vol. 5, no. 1), DICOM is an extremely complex standard, with multiple protocols and specifications. No product could conform to all DICOM standards, and any claim of conformance needs to be evaluated in light of your specific needs.

* the default standard for teleradiology and PACS server operating systems appears to be Windows NT.

* voice recognition still has only one player in the field (IBM’s MedSpeak/Radiology). This should change in the next year, since several companies (Dragon Speak; Kurzweil) now have continuous voice recognition products.

Finally, there is a natural, increasing convergence of PACS and teleradiology technology. For example, it is becoming more common for off-site teleradiology studies to be ported directly into the PACS system (as happens now, for example, with Boston’s VA Hospital teleradiology/PACS system) where they can be called up by radiologists in the central reading room. The lines of distinction should continue to blur over the coming year.

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