Videofluoroscopy with remote assessment is a relatively simple process that involves two major components. The first is a server PC equipped with video encoder hardware, located in the hospital X-ray suite. For the prototype system developed by Perlman and Witthawaskul, a 300-MHz Pentium computer was located in the X-ray suite at Carle Hospital in Urbana, IL. A 700-MHz Pentium computer, called the control and analysis computer, was located in Perlman's lab, about a mile from the hospital. The two machines were connected via the hospital's T1 Internet connection at a maximum speed of 1.5 megabits per second. Perlman, the dysphagia expert, directed the fluoroscopy exam from her lab, communicating with the hospital radiologist and the patient via a simple speakerphone connection. To operate Perlman's system, the hospital's radiologist merely turns on the server computer, then conducts a routine fluoroscopy exam. No special expertise is needed.

			The examination takes place while the patient swallows a small amount of barium solution, which allows the fluoroscope to view the movement of the barium and of various structures in the mouth and throat. The fluoroscopic image is about as close as humans come to having X-ray vision. Skin and hair are transparent, while the skull and other bones, cartilage, and hollow tissues such as the esophagus and windpipe, are clearly visible. As the patient swallows, it is relatively easy to follow what happens. The hospital-based PC digitizes the videofluoroscopic images into an MPEG format and records the patient's swallowing activity in the highest resolution possible. Meanwhile, the video data are transmitted in real time to the control and analysis computer in Perlman's lab.
	A video image of a flouroscopy exam showing the tissue in the head and neck. The video player in the lower right of the image allows images that are transferred to the researcher's lab to be examined by running the video forward and backward, and at varying speeds, including frame-by-frame. Enlarge image.

According to Perlman, the image quality during real-time transmission is adequate for directing the procedure, but does not offer the level of detail that she prefers for diagnosis. Real-time transmissions' low resolution results from the relatively limited bandwidth between the hospital and the lab.

During the examination, the control computer in Perlman's lab obtains and displays the video data in real-time with only a three- to five-second delay—not enough to affect Perlman's ability to direct the procedure or cause undue radiation exposure to the patient. After the examination is completed, high-resolution fluoroscopic images, which were stored on the hospital computer during the examination, are transferred to Perlman's laboratory for complete analysis. Using these high resolution images, Perlman is then able to look at the data frame-by-frame, search the video for specific frames, and adjust the brightness and contrast to better examine the data.