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1 PACS clinical rience at Georgetown University Steven C, Horii, Seong Ki Mun, Larry P. Elliott, Betty Levine, Ben Lo, Brian S. Garra, Robert E:. &man, Matthew Freedman, Clifton Leftridge, Dieter Schellinger, John Keyes, Robert Fielding, Harolld Benson Department of Radiology, Georgetown University Hospital,Washington, D.C , U.S.A. ABSTRACT Georgetown University Hospital has been operating an image management and communications system (IMACS or PACS) for three-and-a-half years. This work was initially funded under the Army Medical Research and Development Corn mand Digital Imaging Network Systems (DINS) project. The system was taken from a research system supporting only radiology tasks to one extended to clinical use, and has been used in clinical work for three years. This paper summarizes our PACS clinical experience and will describe the operational features implemented and those still necessary. INTRODUCTION During the past three and one-half years, we have taken the Georgetown PAC (A T & T Philips CommView) from a large scale prototype to an operational, clinically useful system. There is still a large amount of work remaining before the system can be said to have completely replaced conventional methods of operating the imaging side of a radiology department. We have learned a great deal from these years, and will be applying what we know to the further growth of the system. Most of the work which needs to be accomplished in order to take the system further is not in adding hardware. The development of more tailored sofi;ware is far more important. The technical aspects of this project have been presented in threle sources [Arenson 1990, Elliott 1990, Mun and so will not be reviewed here. PACS in Abdominal Imaging The workstation in the Division reading room is one of the most heavily used. The major change from occasional use to routine use was the result of the changes in release 3 of the CornmView software. Most important was the ability, at the workstation, to restore cases to the central short-term magnetic disk storage from the optical archive. This automatic restore hais proven to be a very attractive feature, and resulted in very heavy use of the system by the radiology residents and fellows. A typical reduction in time spent finding studies was fifteen minutes from the file room (if the films could be found) to five minutes at the workstation. The addition of the high-speed display and large local storage afforded by the "turbo" upgrade increased use even further since these features reduced the delaiy in displaying images and eliminated the problem of a full local disk. The increased capacity and speed, coupled with connection of the fourth ultrasound machine to the IMACS, led the Ultrasound Section to test primary reading at the workstation. The local disk capacity is now large enough to store more than a full day's ultrasound cases. An automatic routing feature eliminates the task of having to load the workstation manually. The pathology seen was displayed equally well on the workstation and on film. Timing studies done to date show that reading from the workstation takes about 30 seconds longer per case than reading from film. This time difference is primarily diae to the time it takes to page through all the images at the workstation. The CT section is using the workstation primarily to retrieve prior cases for connparisoln. Primary reading is inhibited at this time by the video frame-grabbed nature of the imagc;s. Though the resolution is seen to be adequate, the /91 $1.00 Q 1991 IEEE 149

2 lack of the full digital data prevents window and level adjustments on the images. The abdominal MRI section uses the workstation in a similar fashion to CT, but has been operating a digital interface for approximately one year. This has reduced technologist workload by changing the acquisition process to entry of the patient and exam identification followed by a file copy command. Evaluation Studies: Abdominal Imaging Several evaluation studies have been performed, Seventy-eight cases from routine ultrasound studies which had been acquired on the IMACS as well as on film were read in a double-blind fashion by Drs. Gama and Horii of the Ultrasound Section. Comparing their readings, and found no differences in diagnoses or findings [Davros A study of the suitability of digitized film and digital fluoroscopy for endoscopic retrograde cholangiopancreatography (ERCP) was performed by Dr. Zeman (Director of the Abdominal Radiology Division), and the results reported at the 1989 Radiological Society of North America (RSNA) Annual Meeting [Horii 1989al. Fifty proven cases were randomly taken from the files, and the spot films and photospots (those images photographed from the image intensifier output) were digitized on the DuPont LFD. Dr. &man then interpreted these studies at the workstation without knowledge of the original reading. He judged both diagnostic quality as well as image preference (film or CRT image). The results showed no significant differences between the original films and their CRTdisplayed and interpreted counterparts in either diagnostic quality or user preference. PACS in Neuroradiology The Neuroradiology Division also had its workstation upgraded to the EGDW "turbo" configuration. This allows at least a full day's MRI studies and CT head studies to be kept on the system. The Workstation in the Neuroradiology reading room serves primarily for MRI review and comparison. Training of new Neuroradiology Fellows and residents has become routine, and use of the workstation is encouraged while they are on the service. A summary of the use and acceptance of the system by Neuroradiology was presented at the SPIE Medical Imaging 111 meeting in 1989 [HoI-ii 1989bl The only drawback they currently see is that many of the newer MRI studies yield more than 80 images (100 to 120), so that it is no longer possible to view whole examinations at once. For the Neuroradiology Division, the IMACS proved an acceptable clinical toal. In both the teleradiology application and the local reading use, the system proved to be time saving. In the former, this was the result of viewing the images on the same day they were obtained, in some instances within an hour of their being acquired if decisions about the completeness of a study were needed. In the latter, the value has been in retrieving comparison cases. This is also primarily a time saving feature since the neuroradiology MRI reading room is two floors above radiology. PACS in General Radiology The General Radiology Division (consisting of Musculoskeletal and Chest radiology) was the last of the radiology divisions to have an EGDW installed. Without computed radiography on-line, the use of the IMACS by the General staff has been limited. In anticipation of interfacing the CR system, though, the EGDW has been upgraded to the "turbo" version. Most of the use of the workstation in the general reading room has been for review of musculoskeletal MRI or CT. Dr. Matthew Freedman, Director of Thoracic Radiology, has been using the workstation for a number of experiments on performance of the radiologists using film versus the workstation. Early results show that it may be both easier to see lung nodules on the workstation display, and identify them with more confidence. For the last nine months, we have been evaluating phosphor plate radiographic systems (also called computed radiography or CR systems) as a replacement for digitizing films. We have placed a Fuji AC-1 (to be replaced by an AC-2 when available) and an Agfa ADC into operation, and are currently working on interface methodology for these units. Most recently, we I50

have been able to move images from the Agfa system to CommView. Early results with portable radiography confirms what other CR users have found, that such use is clinically acceptable.

3 have been able to move images from the Agfa system to CommView. Early results with portable radiography confirms what other CR users have found, that such use is clinically acceptable. Evaluation Process: General Radiology We undertcok a study of the number of bits of gray scale required for locating catheters and evaluating pulrnonary vasculature on adult portable chest films. The results were that six to seven bits of gray scale were needed at a minimum to see catheters well, and five to six bits to evaluate pulmonary vessels. Overall, seven bits were needed as a minimum in order to see all findings. There were no significant differences between the observers in the number of bits required [Freedman We note that the study should be considered preliminary since it was done with a small number of images, a small number of readeis, and with portable chest films. In General Radiology, much of what happens in the future is tied to interfacing of the CR systems. We will be interested in whether we can move to primary reading from the workstation, arid have planned our studies accordingly. Dr Freedman has been very active in conducting these studies, but the data are not yet ready for publication. PACS in Nuclear Medicine Since Nuclear Medicine is located in a different building and three floors up from Radiology, it is very time consuming for the nuclear medicine: physicians to come to radiology to retrieve or review cases. Since many nuclear medicine studies; are functional, correlation with the anatomic imaging provided by other techniques is necessary for proper diagnostic interpretation. The Nuclear Medicine Division is the heaviest intradepartmental user of correlation studies, and use of their workstation reflects these needs. PACS in the Pediatric Intensive Care Urnit The pediatric intensive care unit (PIClJ) was among the early non-radiology sites considered for a workstation location. The choice was based on the combination of a relatively small number of beds but with an urgent demand for film availability when portable films are done. For this reason, the physicians who work in tlhe unit are reluctant to leave for any length of tine. As for any intensive care unit population, tlhe patients are very ill, and constant attention is a must. The Department had considered installing an alternator for films on the floor, but that would require radiology personnel to load and unload it, and a radiologist to review cases there. Placement of a workstation has avoided this situation. PACS in the Intensive Care Nursery The intensive care nursery (ICN) was the second of our Pediatric Division units ito have: a workstation installed. Its environment aind demands are very similar to those of the PICU. We installed a two-screen EGDW in the ICN area. Training of the ICN personnel was conducted in several sessions. A follow-up formal training session was conducted for the ICN staff by the IMACS vendor personnel when the new software release was installed. Once the release 3 software was installed, the pediatrician usage increased since they could then compare two images side-by-side, and could also restore any case to the system from the optical disk archive. We have installed a video disk recorder/player which is small enough to sit on top of the portable ultrasound machine and records the video images on 5 cm floppy dislks. These can then be played back through the recordedplayer and into the video input port of the acquisition module. Our early experience is that this is a satisfactory method of capitwring rhe portable ultrasound images done in the ICN. As for the Pediatric Intensive Care Unit, rhe physicians in the ICN see the chief benefit of having a workstation on the floor as increasing the time they can spend with very sick patients. PACS for Teleradiology Two major teleradiology projects were undertaken for clinical evaluation. The first was 1.51

4 to operate a teleradiology link to an outpatient imaging center for neuroradiology, and the second has been to use teleradiology for on-call support of ultrasound. The GUH Radiology Department operated an outpatient imaging center in Rockville, Maryland until November, It was the responsibility of the GUH neuroradiologists to read the MRI and some of the CT on neuroradiology referral patients. This volume was not sufficient to warrant a full-time neuroradiologist at MIC, so the initial method of reading was to have the images brought to GUH by courier, or in extreme cases, have a neuroradiologist from GUH drive out to MIC. The former method meant a minimum delay of one day in interpreting the studies, and the latter method, while reducing the delay, was unpopular with the neuroradiologists as it took them away from their responsibilities at the Hospital. As part of the IMACS, a combination acquisition module/workstation was installed at MIC. Communication to GUH was via leased T- 1 service.video digitization of the MRI and CT images was used. Use of the system by Neuroradiology, including primary interpretation of the studies on the EGDW at Georgetown, became routine. Because of a change in the management at MIC, Georgetown did not renew its affiliation contract with the Center. The responsibility to read MIC cases ended in November, The Abdominal Imaging Division radiologists are required to provide 24-hour coverage for emergencies which require their imaging services (primarily ultrasound and CT). This is accomplished by having each member (including Fellows) share the emergency call on a week-long, rotating basis. A feature of the IMACS which impacted this coverage was the availability of a dial-up modem through which one could access the IMACS database. Since the latter half of 1989, we tested this feature by placing a RVS in Dr. Horii's home. He used the workstation whenever he was on-call for ultrasound. Using voice-grade dial-up telephone lines (Dr. Horii's regular phone line) a typical complete study takes minutes to transmit (the modems operate at a 19,200 baud effective rate). The RVS has saved Dr. Horii a trip in to the Hospital approximately 80 percent of the time. On the remaining occasions, the study to be done is complex enough that he must be present to perform it himself. Clinical evaluation has been to review the film images of all cases read on the RVS. Dr. Horii has found no instances in which findings were missed on the RVS and seen on film [Horii As a result of the early success, a second RVS was placed at the home of the Director of Ultrasound, Dr. Garra. He has been using the system since July, 1990, and has found results similar to Dr. Horii's. CONCLUSION The DINS work at Georgetown was successful in demonstrating that a PACS can be clinically useful to radiologists and referring physicians. The main benefit to referring physicians is in time savings. For the radiologists, availability of images and the use of teleradiology for daily and on-call work are beneficial aspects. Much work remains to be done before PACS are easily costjustified, but rapid progress is being made. ACKNOWLEDGEMENT This work was supported in part by the US. Army Medical Research Acquisition Activity of the U.S. Army Medical Research and Development Command under contract number DAMA C The views and opinions expressed in this paper are those of the authors and should not be construed to to represent official Department of the Army positions, policies, or decisions unless SO designated by other documents. 152

5 Arenson 1990 Elliott 1990 Mm 1989 Davros 1988 Horii 1989a Horii 1989b Freedman 1989 Horii 1991 Arenson, R.L. and Fridenberg, R.M. (eds.): SICAR '90: Computer Applications to Assist Radiology, pp Symposia Foundation, Carlsbad, CA, Elliott, L.P., Mun, S.K., Horii, S.C.: Digital Imaging Network System (DINS) Evaluation Report, MITRE Contract number N-55201, pp , March, Mun, S.K., Benson, H., Horii, S., Elliott, L.P., Lo, S.-C. B., Levine, B., Braudes, R., Plumlee, G., Garra, B., Schellinger, D., Majors, B.:Completion of' a hospital-wide comprehensive image management and communication system. Proceedings of the SPIE, v. 1093, Medical Imaging 111, pp ,1989. Davros, W. J., Garra, B.S., Ingeholm, M.L., Mun, S.K., Zeman, R.K.: The impaict of PACS on a clinical ultrasound service. Scientific Exhibit number 1245, 1988 AIUM/WFLJMB Meeting, Washington, D.C., October, Horii, S.C., Garra, B.S., Zeman, R.K., Lo, S.-C. B., Davros, W., Silvermam, P.M., Cattau, E.L., Fleischer, D.E., Benjamin, S.B.: Endoscopic Retrogralde Cholangiopancreatography: Prospective Evaluation of Traditional Fillm-based Images, Digitized Images, and Digital Fluoroscopy. Annual meeting of thie RSNA, November, Horii, S.C., Muraki, A., Mallon-Ingeholm, M.L., Mun, S.K., Clark, Id., Schellinger, D.: A complete image management and communications network for the Neuroradiology Service of Georgetown University Hospital. Proceedings of the SPIE, v. 1093, Medical Imaging 111, pp , Freedman, M., Horii, S., Garra, B., Braudes, R., Lo, B.,Mun, S.K.: Evaluation of Digitization Dynamic Range in Laser-Digitized Adult Portable Chest Radiographs. Annual meeting of the RSNA, November, Horii, SC, Garra, BS, Mun, SK, Zeman, RK, Levine, B, Fielding, R: PACS and teleradiology for on-call support in abdominal imaging. Roc. SPIE v. 1446, Medical Imaging V, in press. 153

INTRODUCTION TO DICOM FOR THE PRACTICING VETERINARIAN

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