Portable echo could lead to portable x-ray

Doctors in Texas have transmitted live images of the heart and vessels of patients from moving ambulances to emergency rooms for evaluation ahead of the patient's arrival. The two-way voice/data communications technology allows reviewing cardiologists to remotely direct examinations from as far as 20 miles away, while ambulances travel over 60 mph.

Doctors from the Brooke Army Medical Center at Fort Sam Houston and engineers from the Southwest Research Institute in San Antonio used handheld ultrasound units configured to transmit 2D images of the patients' hearts and vessels from ambulances, according to a paper presented at the American Society of Echocardiography's meeting in June. Images are transmitted to the hospital emergency department using the existing metropolitan traffic management fiber-optic network, broadband radio technology, and video compression techniques.

The technology raises the possibility of transmitting digital x-rays from moving ambulances, provided the vehicles are equipped with a portable imaging modality, which exists in prototype form. The Army has devised a portable digital radiography unit that is being evaluated for frontline support of field medical operations.

Designed by Dr. Kenneth Cho, of the radiology department at Tripler Army Medical Center in Honolulu, the prototype portable DR device is built with commercially available equipment. The electronic detector and associated hardware are housed in specially designed aluminum cladding.

Cho's prototype demonstrates that it is possible to acquire high-quality digital images in the field using DR, although more work is needed to decrease the system's size, weight, and cost. The prototype weighs 250 pounds, too heavy certainly for soldiers, but not necessarily for emergency vehicles.

The idea of transmitting x-rays from ambulances has yet to be demonstrated or seriously studied.

"Any video or still image of moderate resolution is transmittable as a live picture," said E. Sterling Kinkler Jr., a principal engineer at Southwest Research Institute. "Images that involve higher resolution requirements, typical of high-resolution digital x-rays, are also transmittable as a store-and-forward image, which may take a few seconds. Very large image files may even take a few minutes to transmit."

Still, the ability to triage patients before they arrive at the hospital would improve the delivery of patient care and may aid in relieving overburdened emergency rooms.