What is emergency medicine? This field was not even recognized as a specialty of medicine 20 years ago. Not only is it now a recognized field of medicine, it is now delivering close to 10% to 15% of the health care in this country. Patients are driven to the emergency department (ED) for their health care because this is the only widely available form of medical delivery system after hours and on weekends. Many ailments such as cough, influenza, and gastroenteritis, formerly treated by internists and family physicians, are often being treated in the ED. Because of increasing control of access to medical care by insurance companies, more and more patients have discovered visiting emergency departments to be the quickest way of accessing medical care for their problems. Thus, a whole new field of emergency medicine has emerged in recent years that delivers medical care ranging from relatively minor ailments to truly life-threatening emergencies.

How do these changes impact radiology? Greatly. Radiology is one of the major support systems to emergency medicine. With increasing medical care being shifted to the ED, greater and greater demands are put on radiological services. In addition, there has also been major advancement in recent years in the treatments of certain diseases that now mandate immediate radiological studies. For instance, patients presenting with symptoms of stroke used to be managed conservatively, but now, with tissue plasminogen activator therapy and potential vascular intervention, CT or MRI of the brain has become the standard emergency study for these patients. Those who are suspected of having pulmonary embolism or kidney stones are frequently evaluated by spiral CT scans. Patients presenting with chest pain may require evaluation with nuclear cardiac studies. The combination of these factors brought about a major surge in demand in radiological services.

Due to these developments, the lives of radiologists throughout the country have been forever changed. With the great number of after-hours calls and the frequent round trips at night to the hospital, what was once a gentleman’s practice has become an extremely stressful profession. Technology came to the rescue of the radiologists in the later part of the 1980s with the development of teleradiology, through which radiological studies can be transmitted via telephone lines to the radiologists’ homes. Many radiology groups declined to adopt teleradiology to their practice initially because of the fear of possible negative reaction from the referring physicians, a reaction that never really materialized. Most referring physicians accepted this advance primarily because teleradiology actually improves service to the referring physicians by reducing the response time of the radiologists. Now the standard of care for radiology coverage, teleradiology has proven to be a double-edged sword. Although it has improved the lifestyles of the radiologists, it has partly contributed to the significant increase in after-hours radiological studies. This is due to the fact that referring physicians have become less reluctant to order more examinations because they are becoming accustomed to the new technology.

Even with teleradiology, calls have become so stressful for radiologists that many are quitting their profession prematurely. A recent survey showed more than 65% of the responding radiologists rated being on-call as the most stressful part of their profession. Call scheduling has become a focal point of conflict within radiological groups, sometimes even exceeding compensation. The senior radiologists would like to take fewer calls, while the more junior radiologists want the calls to be distributed more evenly. Some groups allow the senior members to pay other members to take their calls. The exchange rate for the call then becomes another point of disagreement.

The current on-call coverage for most radiological groups does not utilize the radiologists’ time efficiently. Most groups have one radiologist on call for one to two hospitals. The radiologists get calls intermittently. They cannot do many of the activities they would like to do for fear of being called. Their sleep cycle is frequently interrupted. A related issue is that the on-call radiologists are not functioning with 100% of their faculties the day after the call.

One solution to this very complex problem is a night-call service or a teleradiology network. In late 1997, with the cooperative efforts of six radiology groups, a teleradiology center was established in the greater Los Angeles area. Initially, six hospitals went online with the network, but in the previous 2 years there has been tremendous growth in the network, and after-hours radiology coverage is being provided to 40 hospitals in California.

The Technology

Taking advantage of the current teleradiology technology, the radiological studies from various hospitals are transmitted to a central reading station. The teleradiology equipment used at the center came from various vendors. This is because most radiology groups generally had already purchased equipment prior to the formation of the network. It would have been extremely expensive to convert all of the hospital groups to one single system simultaneously.

Approximately 40% of the cases received are computed tomogaphy (CT) of the head. Common indications for the studies are trauma, cerebral vascular accidents, altered level of consciousness, headaches, and change of mental status. Pelvic and abdominal ultrasound studies are frequently ordered for evaluation of pain. Ultrasound makes up 20% of the cases. CT scans of the abdomen and pelvis are used to evaluate traumatized patients and those presenting with acute abdominal pains. These studies make up another 20% of the cases. The remaining 20% of cases is composed of various plain film studies, CT of the spine, ventilation and perfusion lung scans, and MRI studies.

Nearly 90% of the radiology groups have direct-capture units using frame-grabbing technology to capture CT images and sometimes ultrasound images. The images are captured and stored in JPEG format generally compressed at a 10:1 to 15:1 ratio. Some digital studies (CT, ultrasound, and nuclear medicine) and plain radiographs are captured using a charge-coupled device or laser scanner at 1K to 2K resolutions. These images are generally compressed at a 5:1 to 15:1 ratio and are stored in JPEG format. Even though the wavelet compression technique can compress the images at a much higher ratio, it is not yet considered DICOM compliant. Currently none of the groups in the network are using wavelet compression.

Even though most network venders utilize the JPEG format, there are no standards for storage and display of these images. All teleradiology vendors are very secretive about their proprietary software, and one vendor’s viewing software cannot be used to view other vendors’ images. It became necessary to set up multiple viewing stations in order to receive and review the studies. This makes the operation somewhat inefficient, because the radiologists must move from viewer to viewer to review studies from various hospitals. The use of multiple receive-units, however, helps to build redundancy into the system and provides backup in case one or two systems fail.

The network is actively investigating an integrated approach using a server, which is able to receive studies from various sites from various vendors and then send the studies to a workstation. We are also trying to convert some of the sites to DICOM format, which would allow the direct transmission of the digital studies without having to frame-grab them first. The DICOM format enables the radiologists to perform true window leveling very much like sitting at the CT or MRI workstation. DICOM studies eliminate the need for capturing of individual images, reducing the workloads of the radiology technicians. Unfortunately, DICOM files are generally very large and take longer to transmit.

Because the standard modems are able to transmit only at 28- to 56-bps rates, they are not adequate in general to transmit large image data files. Most of our systems utilize ISDN telephone lines to transmit their studies. They transmit at 115 bps. Unfortunately, ISDN lines are difficult to configure and at times unreliable. We frequently encounter problems when transmitting across different telephone company lines. Because of the increasing demand for faster transmission of studies, we are converting many of the busy hospitals to digital subscriber lines (DSLs), T1, or cable modems. We have set up virtual private networks (VPNs) and firewalls in order to transmit these studies over the Internet.

Numerous benefits

On review of the network experience, numerous advantages of this system become apparent:

  • Efficient use of radiologists’ time: Instead of having 20 to 30 radiologists on call for 30 to 40 hospitals, this system would have one or two radiologists covering the entire network at the same time. Ancillary personnel are employed at the central station to provide support to the radiologists. Such support personnel help the radiologists to interact with the hospital technologists and ED physicians and to generate timely reports.
  • Specialized radiologists: Because these radiologists constantly are reviewing urgent or emergency cases, they have gained more experience in interpreting these types of studies than most radiologists in general. In essence, they have become specialists in the field of emergency radiology.
  • Advanced teleradiology equipment: Compared to the individual radiologists taking calls from their homes, far more advanced teleradiology equipment can be used at the central station because of amortization of cost.
  • Better communication: One of the greatest fears of the architects of the network when it was formed was that the ED physicians would complain about not knowing who was reading the cases. This fear was proven later to be unfounded. Because the same group of radiologists are reading the ED cases on a daily basis, close working relationships between the on-call radiologists and the ED physicians have often been established. In general, technicians and ED physicians would prefer to speak with a radiologist who is awake and friendly than a radiologist who is annoyed at being awakened in the later hours. Most ED physicians also prefer the typewritten preliminary reports to the verbal reports because of the potential for communication error.
  • Quality assurance: Because of the limitations of teleradiology equipment and the problem of insurance billing, the nighttime reports in our network are provided as preliminary reports only. All the emergency studies are double-read by the daytime radiologists the next morning. Any discrepancies are immediately called to the attention of the ED and referring physicians and to the nighttime radiologist.
  • Cost: Because the compensations of the nighttime radiologists and the cost of the center are being shared by multiple groups in the network, the overall cost of the after- hours coverage per group or per radiologist is far less than the cost would have been had the individual group hired their own radiologists for after-hours coverage.
  • Quality of life: The quality of life of the radiologists participating in the network dramatically improved after it was created. Their outlook in their profession is much improved as well.

What is in the future? With the introduction of teleradiology, the teleradiology network will become the standard for after-hours radiology coverage. The rapid advancement of Internet technology ensures that the teleradiology network will eventually move completely to the Internet. All forms of communication — including transmission of images and reports — will be conducted through the Internet using DSL and other wideband transmission of information. The radiology report along with selected images will be sent to the referring physicians or ED physicians. Discussion can also take place between the physicians using the Internet. Radiographic studies will be stored in the Internet server so that physicians can access them anywhere in the world. Such technologies will allow us to bring the highest quality of medical care even to the remote areas of the United States.

Wilson S. Wong, MD, is president of Teleradiology Diagnostic Services Inc, Arcadia, Calif.