- Email: [email protected]
Beyond PACS: getting images to referring physicians
Beyond PACS: Getting Images to Referring Physicians David Avrin, MD, PhD, Richard H. Wiggins, III, MD, and Cameron Bahr, BS PACS IMPLICATIONS FOR THE INSTITUTION
F
ILM AS A STORAGE MEDIA, and for image viewing, is rapidly becoming an endangered species in our large acute care institutions, and for good reason. An increasing percentage of diagnostic imaging is created by the digital modalities: CT, MR, Ultrasound, Nuclear Medicine, and PET. These modalities are generating significantly increased numbers of images per study, particularly multi-detector CT and the new MR sequences. Studies consisting of several hundred or more images, with comparisons, are difficult to manage on film, even at 15 to 20 images per sheet. In addition, digital substitutes for conventional projection radiography, computed radiography (CR) and direct digital radiography (DR) are increasingly deployed in larger and not infrequently smaller remote healthcare facilities. Technologies for storage and storage management now exist that allow these huge archives of patient data to be stored and retrieved cost-effectively, without lost or missing studies. In addition, workstations separate from or integrated with a computerized patient record (CPR) allow imaging studies to be retrieved and reviewed anywhere, anytime, as the clinical situation dictates. Integration with other systems for access to reports, orders and other clinical information is essential. Finally, many institutions now have the high speed-networking infrastructure to support this technology effectively at 100 Mbits to 1 Gbit per second. Clinicians expect and deserve timely and effective access to imaging studies on their patients, at the point of care or in their office.
From the Department of Radiology, Division of Neuroradiology, University of Utah School of Medicine, Salt Lake City, UT. Address reprint requests to Richard H. Wiggins, III, MD, Department of Radiology, Division of Neuroradiology, University of Utah School of Medicine, 1A71 University Hospital, 50 North Medical Drive, Salt Lake City, UT 84132-1140; e-mail: [email protected] © 0 Elsevier Inc. All rights reserved. 0887-2171/⫺2000/000-0000$30.00/0 doi:10.1053/j.sult.2003.09.009 428
THE FILMLESS IMPERATIVE FOR CROSSSECTIONAL MODALITIES
How does a clinician, or a radiologist, review or evaluate a CT or MR study consisting of 300 images, for example? Fifteen to 20 sheets of film are minimally required to record such a study, and that is for only one window/level combination. Additional window and level combinations are required to display a subset of the images for lung and liver, and quite possibly the entire set for bone evaluation. Add to this the importance, and the necessity, of comparison to one or more prior studies, and you have a gargantuan task. In today’s PACS equipped radiology departments, radiologists use “stack mode” to rapidly navigate through 3D datasets, evaluating each organ as a separate entity, and quickly switching window and level combinations for optimum evaluation. Many commercial workstation software solutions exist that provide these radiologists with an estimated 50% increase in efficiency. Similar capabilities can now be deployed to the enterprise. THE ENVIRONMENTS: RANGE OF ACUITY
Now that we have defined some of the challenges, what solutions are available for the enterprise outside of radiology? Fortunately, there is a range of solutions, from multiple vendors, to address the problem of imaging study distribution to the enterprise. The optimum technical solutions are appropriately matched to the clinical environment, for care and cost reasons. Common environments, listed in order of acuity, include the Emergency Department, Operating Rooms, various ICU’s, Pre- and Post-Anesthesia Care, Surgical, Medical and Pediatric wards, Urgent Care centers, and Clinics. In addition, access in physician offices and exam rooms, in both the academic and community models is required. Any environment that traditionally had need for imaging access via film now needs digital access. In most institutions, the ED, ORs and ICUs are provided relatively full function client workstations, often on the same network as the radiology department workstations, and often with dual monitors. Higher resolution monitors may be provided to environments viewing large quantities of plain radiographs. These workstations tend to be expen-
Seminars in Ultrasound, CT, and MRI, Vol 24, No 6 (December), 2003: pp 428-433
BEYOND PACS
429
Fig 1.
Configuration options for Web access in conjunction with PACS.
sive, and software maintenance and upgrades often requires that a technician personally visit the workstation. At the other end of the spectrum are various Web server/browser solutions. These provide two very significant advantages: 1. Wide deployment with no maintenance/upgrade support other than minimum system configuration, including a browser such as Internet Explorer™ (Microsoft Corp., Redmond WA) 2. Universal secure access to imaging studies. As such, they effectively provide a catchall safety net for enterprise filmless transition. The disadvantages of these systems are relative: in general, they are usually configured for a single monitor, although multiple series or studies can usually be displayed at once. Study access is network and server dependent. Although some can work satisfactorily over telephone modem (approximately 0.05 Mbits/sec), most are designed for at least broadband access speeds (0.5-2.0 Mbits/ sec). The implication is that remote offices or clinics (sometimes not physically remote; i.e., in the neighborhood) require reasonable network ac-
cess, either from the institution or through a high speed internet service provider via cable in the street, cable modem or DSL over phone line. THE TECHNOLOGY ISSUES/SOLUTIONS
Currently, there are four alternatives for workstation platform/architecture. In addition, there are alternatives for how workstations access the digital medical image archive (see Fig 1). Within the diagnostic imaging department, workstations used for diagnostic interpretation consist of at least two and at times up to four monitors. These may be high resolution (2.5K lines). The user interface may be more complex, with full sets of tools for measurement, etc. In addition, they may have advanced database client integration to generate worklists based upon modality, unread studies, etc. These workstations tend to reside “inside the firewall” directly on the internal PACS high-speed network. High clinical use/high acuity areas within the hospital/clinic may have “clinical” workstations of similar capabilities. Since there is always a tradeoff between complexity and user-friendliness, these workstations for use by sophisticated clini-
430
AVRIN, WIGGINS, AND BAHR
Fig 2.
Screen shot appearance of a Web services type of client workstation.
cians may have somewhat “detuned” user interfaces, and lack some of the workflow integration tools needed within the radiology department. They are most often dual monitor, and are usually of medium high-resolution (1.6K). This type of workstation is often deployed in the Emergency Department, ICUs, and high use outpatient clinics. It most often resides on the internal PACS network, as shown in Fig 1. The third variation is relatively new, taking advantage of new software technology for netbased applications. It runs under a “net services” protocol (Microsoft or generic), and can deliver a virtually identical user interface and functionality as the clinical workstation described above. The application is “delivered” over the network, rather than being “installed” on the workstation, which allows for easier maintenance and upgrade of large numbers of clients. This technology relies upon a central net services server and does depend upon
fast networks: 100 Mbit, or even better, Gigabit Ethernet. These workstations can be configured with dual monitors. Typical screen appearance is shown in Fig 2, and is identical to the traditional full client. Finally is the traditional Web client, a very functional tool, shown in Fig 3. This configuration opens as an applet or servlet program (or combination) within a standard Web browser such as Internet Explorer, accessing a Web server designed for medical imaging functionality. Most often, these workstations are single monitor, and have more limited viewing tools. However, they provide image access from any computer meeting the minimum specifications with network access and security permission. Increasingly, this functionality is being integrated with a computerized patient record. These last two types of workstations both access a Web server rather than the core PACS servers.
BEYOND PACS
431
Fig 3.
Screen shot appearance of traditional Web server client.
It should also be mentioned that at least one PACS vendor offers a completely Web-based architecture. That is, even the radiology department diagnostic workstations are Web clients. This design has the advantage that there is no distinction between image access from the enterprise, and from within the radiology department, since both environments access the same server and data store. The last two of the “served” workstations present challenging design issues relating the server database and image archive to the PACS database and image archive. Referring to Fig 1, the Web clients need to access the Web server to function and obtain studies/images. The Web server can be populated in one of two ways: (1) it can be integrated with the PACS and receive its images from the PACS, after the PACS has received (and verified) them from the imaging modality devices; or (2) it can be a separate, parallel
system that receives its images directly from the modalities. While (1) is preferred in principle, in reality it has been a challenge for model (1) to perform adequately, because of delay and queuing of study transfer from the PACS to the Web server, particularly at times of heavy load during peak times of the day. In addition, smaller studies destined for a rapid turn-around clinic may be delayed behind a larger MR study of less acuity, for example. Hardware speed and “multi-threading” software techniques are being used to address this problem. Even with the integrated model, it can be difficult to synchronize the Web server database with the PACS database, particularly regarding demographic corrections; and selection and availability of relevant prior studies. If a needed study is not on the Web server, retrieval from the PACS may be frustratingly slow. On the other hand, running an independent,
432
AVRIN, WIGGINS, AND BAHR
parallel Web server can be a significant timeconsuming task for the support team, and database synchronization is extremely difficult. However, some institutions have successfully resorted to this solution to satisfy the needs of the enterprise. It is clear then, that sufficient Web server archive size should be provided so that a large store of studies is immediately available. In addition, optimum-prefetching algorithms should be implemented, to maximize the likelihood that a needed relevant prior study is available from the Web server without query back to the PACS. In addition, recent studies suggest that significant compression of conventional projection radiographs can be done without diagnostic compromise, which can increase the number of stored studies on the same size RAID by an order of magnitude. THE DIFFICULT ENVIRONMENTS
In my experience at two academic institutions (UCSF and University of Utah), and from experiences related by others, certain care environments and certain specialties have larger challenges adopting and adapting to digital medical imaging technology. It is safe to say that all institutions have found the operating room difficult, and many different solutions have been attempted:3 1. Print film. 2. Install preloaded standalone or clinical workstations in the OR with at least dual LCD monitors (wall mounted or ceiling suspended). 3. Make the PACS monitor controls surgeon accessible through a sterile touch screen, sterile wireless mouse, or mouse wand with trackball. 4. Try to mitigate costs by mounting clinical workstations on carts (laptop or small cabinet PCs) with LCDs mounted on cart tops, relying upon network access in every OR preloading with relevant case material. 5. Web client solution. Issues that need to be resolved by a team approach include: 1. Platform, i.e., Web client workstation versus PACS network workstation; 2. Portable versus fixed installation; 3. Number and type of monitors; 4. Location of monitors: wall, cart, hung; 5. Control of user interface; 6. Special tools such as templates and true size
display. Consistency must be maintained between the inherent geometric image magnification in projection radiography and template sizing. Digital templates for workstations are being developed. The other environment is the busy outpatient clinic with high dependence on projection radiography (CR or DR), such as orthopedics or chest clinic.2 Limited number of monitors on a workstation (eg, one or two) for CR/DR presents more of a user interface challenge than for CT or MR, which because of lower inherent spatial resolution can be displayed in multiple windows on the screen. One solution is the ability to view, e.g., CR projection images four on one with instant click full-screen blowup. ED solutions that are deployed today are generally considered satisfactory. It is advantageous to have image display capability in a casting room. One of the most common problems in the ICU environment is the placement of the workstation, of any variety, in a location with high ambient light. Flat panel monitors and CRT displays in general have a lower luminance that transilluminated film on a viewbox. The visual perception of contrast and detail is inversely related to the amount of ambient light. Unfortunately, it is not uncommon to visit ICUs in PACS equipped hospitals and see ICU workstations located next to a bright window. THE DIFFICULT SPECIALTIES
Neurosurgeons often prefer PACS in the operating room.1 Two reasons are that they are used to three-dimensional visualization for planning, and they already have CT and MR guided surgical devices, and are used to operating in this technical environment. While CR and DR have slightly lower spatial resolution than conventional film-screen, enough studies have been done5 that demonstrate comparable accuracy for subtle fractures and other abnormalities, partly because of other visualization and enhancement tools in PACS workstations. Clinical workflow and user interface have been the major challenge for orthopedics. Traditionally most orthopedic clinics have close physical access to a radiographic room (and that continues with PACS), but after the image is exposed the traditional and new paths diverge dramatically, and don’t easily converge back to the point of care (the
BEYOND PACS
433
examination room). It is rare to walk into a traditional orthopedic clinic without at least a small set of viewboxes in each room. Understandably, most orthopedists are concerned about replacing that functionality with a single monitor Web client. In addition, where film once served as the image detector, archive media, and display device, and was physically within the environment as it emerged from a chemical processor, in the PACS clinic, the CR plate is placed in a local reader (or DR device), but the image is transferred to the central PACS server for demographic verification, queuing for hierarchical storage, transferred to accessible PACS RAID storage and Web server RAID cache, before it is available for viewing in the clinic. Unfortunately, many factors can combine to make this process sufficiently slow that clinician and patient are kept waiting. And when the images are available, viewing them on a single monitor Web client may not be considered acceptable. What are reasonable viewing expectations in a clinic? Most clinicians, including surgeons, agree that the most important issues in enterprise acceptance of digital imaging are system reliability,
response time of retrieval, and simple user interface. Image quality is not considered an issue if appropriately sized monitors are provided. SUMMARY
The digital imaging hospital has the potential advantage that imaging studies are available anytime, and anywhere they are needed, with negligible loss. Fulfilling this promise in reality, however, presents challenges as described in this paper. No single best formula for successful deployment exists, since each institution is unique, and its medical staff may have varying preferences. This requires a collaborative team approach to design a solution acceptable to all parties, inside and outside of radiology. We have attempted to identify the significant issues. In addition, hardware and software technology continuously evolve and improve. What is clear is that all institutions will adopt this technology for the reasons described. The successful implementations will be those that are collaboratively and thoughtfully designed. User training of all members of the healthcare team involved with image study access is essential.
REFERENCES 1. Yousem DM, Beauchamp NJ Jr: Clinical input into designing a PACS. J Digit Imaging 13:19-24, 2000 2. Kirsch KR, Brown JA, Geis JR: Clinical acceptance and use of a filmless radiology department in a community hospital. J Digit Imaging 16:45-47, 2003 (suppl 1) 3. Bennett WF, Tunstall KM, Skinner PW, Spigos DG: Delivering images to the operating room: A web-based solution. J Digit Imaging 15:137-139, 2002 (suppl 1)
4. Andriole KP, Avrin DE, Yin L, Gould RG, Arenson RL: PACS Databases and enrichment of the folder manager concept. J Digit Imaging 13:3-12, 2000 5. Slone RM, Muka E, Pilgram TK: Irreversible JPEG compression of digital chest radiographs for primary interpretation: Assessment of visually lossless threshold. Radiology 228:425429, 2003
F
ILM AS A STORAGE MEDIA, and for image viewing, is rapidly becoming an endangered species in our large acute care institutions, and for good reason. An increasing percentage of diagnostic imaging is created by the digital modalities: CT, MR, Ultrasound, Nuclear Medicine, and PET. These modalities are generating significantly increased numbers of images per study, particularly multi-detector CT and the new MR sequences. Studies consisting of several hundred or more images, with comparisons, are difficult to manage on film, even at 15 to 20 images per sheet. In addition, digital substitutes for conventional projection radiography, computed radiography (CR) and direct digital radiography (DR) are increasingly deployed in larger and not infrequently smaller remote healthcare facilities. Technologies for storage and storage management now exist that allow these huge archives of patient data to be stored and retrieved cost-effectively, without lost or missing studies. In addition, workstations separate from or integrated with a computerized patient record (CPR) allow imaging studies to be retrieved and reviewed anywhere, anytime, as the clinical situation dictates. Integration with other systems for access to reports, orders and other clinical information is essential. Finally, many institutions now have the high speed-networking infrastructure to support this technology effectively at 100 Mbits to 1 Gbit per second. Clinicians expect and deserve timely and effective access to imaging studies on their patients, at the point of care or in their office.
From the Department of Radiology, Division of Neuroradiology, University of Utah School of Medicine, Salt Lake City, UT. Address reprint requests to Richard H. Wiggins, III, MD, Department of Radiology, Division of Neuroradiology, University of Utah School of Medicine, 1A71 University Hospital, 50 North Medical Drive, Salt Lake City, UT 84132-1140; e-mail: [email protected] © 0 Elsevier Inc. All rights reserved. 0887-2171/⫺2000/000-0000$30.00/0 doi:10.1053/j.sult.2003.09.009 428
THE FILMLESS IMPERATIVE FOR CROSSSECTIONAL MODALITIES
How does a clinician, or a radiologist, review or evaluate a CT or MR study consisting of 300 images, for example? Fifteen to 20 sheets of film are minimally required to record such a study, and that is for only one window/level combination. Additional window and level combinations are required to display a subset of the images for lung and liver, and quite possibly the entire set for bone evaluation. Add to this the importance, and the necessity, of comparison to one or more prior studies, and you have a gargantuan task. In today’s PACS equipped radiology departments, radiologists use “stack mode” to rapidly navigate through 3D datasets, evaluating each organ as a separate entity, and quickly switching window and level combinations for optimum evaluation. Many commercial workstation software solutions exist that provide these radiologists with an estimated 50% increase in efficiency. Similar capabilities can now be deployed to the enterprise. THE ENVIRONMENTS: RANGE OF ACUITY
Now that we have defined some of the challenges, what solutions are available for the enterprise outside of radiology? Fortunately, there is a range of solutions, from multiple vendors, to address the problem of imaging study distribution to the enterprise. The optimum technical solutions are appropriately matched to the clinical environment, for care and cost reasons. Common environments, listed in order of acuity, include the Emergency Department, Operating Rooms, various ICU’s, Pre- and Post-Anesthesia Care, Surgical, Medical and Pediatric wards, Urgent Care centers, and Clinics. In addition, access in physician offices and exam rooms, in both the academic and community models is required. Any environment that traditionally had need for imaging access via film now needs digital access. In most institutions, the ED, ORs and ICUs are provided relatively full function client workstations, often on the same network as the radiology department workstations, and often with dual monitors. Higher resolution monitors may be provided to environments viewing large quantities of plain radiographs. These workstations tend to be expen-
Seminars in Ultrasound, CT, and MRI, Vol 24, No 6 (December), 2003: pp 428-433
BEYOND PACS
429
Fig 1.
Configuration options for Web access in conjunction with PACS.
sive, and software maintenance and upgrades often requires that a technician personally visit the workstation. At the other end of the spectrum are various Web server/browser solutions. These provide two very significant advantages: 1. Wide deployment with no maintenance/upgrade support other than minimum system configuration, including a browser such as Internet Explorer™ (Microsoft Corp., Redmond WA) 2. Universal secure access to imaging studies. As such, they effectively provide a catchall safety net for enterprise filmless transition. The disadvantages of these systems are relative: in general, they are usually configured for a single monitor, although multiple series or studies can usually be displayed at once. Study access is network and server dependent. Although some can work satisfactorily over telephone modem (approximately 0.05 Mbits/sec), most are designed for at least broadband access speeds (0.5-2.0 Mbits/ sec). The implication is that remote offices or clinics (sometimes not physically remote; i.e., in the neighborhood) require reasonable network ac-
cess, either from the institution or through a high speed internet service provider via cable in the street, cable modem or DSL over phone line. THE TECHNOLOGY ISSUES/SOLUTIONS
Currently, there are four alternatives for workstation platform/architecture. In addition, there are alternatives for how workstations access the digital medical image archive (see Fig 1). Within the diagnostic imaging department, workstations used for diagnostic interpretation consist of at least two and at times up to four monitors. These may be high resolution (2.5K lines). The user interface may be more complex, with full sets of tools for measurement, etc. In addition, they may have advanced database client integration to generate worklists based upon modality, unread studies, etc. These workstations tend to reside “inside the firewall” directly on the internal PACS high-speed network. High clinical use/high acuity areas within the hospital/clinic may have “clinical” workstations of similar capabilities. Since there is always a tradeoff between complexity and user-friendliness, these workstations for use by sophisticated clini-
430
AVRIN, WIGGINS, AND BAHR
Fig 2.
Screen shot appearance of a Web services type of client workstation.
cians may have somewhat “detuned” user interfaces, and lack some of the workflow integration tools needed within the radiology department. They are most often dual monitor, and are usually of medium high-resolution (1.6K). This type of workstation is often deployed in the Emergency Department, ICUs, and high use outpatient clinics. It most often resides on the internal PACS network, as shown in Fig 1. The third variation is relatively new, taking advantage of new software technology for netbased applications. It runs under a “net services” protocol (Microsoft or generic), and can deliver a virtually identical user interface and functionality as the clinical workstation described above. The application is “delivered” over the network, rather than being “installed” on the workstation, which allows for easier maintenance and upgrade of large numbers of clients. This technology relies upon a central net services server and does depend upon
fast networks: 100 Mbit, or even better, Gigabit Ethernet. These workstations can be configured with dual monitors. Typical screen appearance is shown in Fig 2, and is identical to the traditional full client. Finally is the traditional Web client, a very functional tool, shown in Fig 3. This configuration opens as an applet or servlet program (or combination) within a standard Web browser such as Internet Explorer, accessing a Web server designed for medical imaging functionality. Most often, these workstations are single monitor, and have more limited viewing tools. However, they provide image access from any computer meeting the minimum specifications with network access and security permission. Increasingly, this functionality is being integrated with a computerized patient record. These last two types of workstations both access a Web server rather than the core PACS servers.
BEYOND PACS
431
Fig 3.
Screen shot appearance of traditional Web server client.
It should also be mentioned that at least one PACS vendor offers a completely Web-based architecture. That is, even the radiology department diagnostic workstations are Web clients. This design has the advantage that there is no distinction between image access from the enterprise, and from within the radiology department, since both environments access the same server and data store. The last two of the “served” workstations present challenging design issues relating the server database and image archive to the PACS database and image archive. Referring to Fig 1, the Web clients need to access the Web server to function and obtain studies/images. The Web server can be populated in one of two ways: (1) it can be integrated with the PACS and receive its images from the PACS, after the PACS has received (and verified) them from the imaging modality devices; or (2) it can be a separate, parallel
system that receives its images directly from the modalities. While (1) is preferred in principle, in reality it has been a challenge for model (1) to perform adequately, because of delay and queuing of study transfer from the PACS to the Web server, particularly at times of heavy load during peak times of the day. In addition, smaller studies destined for a rapid turn-around clinic may be delayed behind a larger MR study of less acuity, for example. Hardware speed and “multi-threading” software techniques are being used to address this problem. Even with the integrated model, it can be difficult to synchronize the Web server database with the PACS database, particularly regarding demographic corrections; and selection and availability of relevant prior studies. If a needed study is not on the Web server, retrieval from the PACS may be frustratingly slow. On the other hand, running an independent,
432
AVRIN, WIGGINS, AND BAHR
parallel Web server can be a significant timeconsuming task for the support team, and database synchronization is extremely difficult. However, some institutions have successfully resorted to this solution to satisfy the needs of the enterprise. It is clear then, that sufficient Web server archive size should be provided so that a large store of studies is immediately available. In addition, optimum-prefetching algorithms should be implemented, to maximize the likelihood that a needed relevant prior study is available from the Web server without query back to the PACS. In addition, recent studies suggest that significant compression of conventional projection radiographs can be done without diagnostic compromise, which can increase the number of stored studies on the same size RAID by an order of magnitude. THE DIFFICULT ENVIRONMENTS
In my experience at two academic institutions (UCSF and University of Utah), and from experiences related by others, certain care environments and certain specialties have larger challenges adopting and adapting to digital medical imaging technology. It is safe to say that all institutions have found the operating room difficult, and many different solutions have been attempted:3 1. Print film. 2. Install preloaded standalone or clinical workstations in the OR with at least dual LCD monitors (wall mounted or ceiling suspended). 3. Make the PACS monitor controls surgeon accessible through a sterile touch screen, sterile wireless mouse, or mouse wand with trackball. 4. Try to mitigate costs by mounting clinical workstations on carts (laptop or small cabinet PCs) with LCDs mounted on cart tops, relying upon network access in every OR preloading with relevant case material. 5. Web client solution. Issues that need to be resolved by a team approach include: 1. Platform, i.e., Web client workstation versus PACS network workstation; 2. Portable versus fixed installation; 3. Number and type of monitors; 4. Location of monitors: wall, cart, hung; 5. Control of user interface; 6. Special tools such as templates and true size
display. Consistency must be maintained between the inherent geometric image magnification in projection radiography and template sizing. Digital templates for workstations are being developed. The other environment is the busy outpatient clinic with high dependence on projection radiography (CR or DR), such as orthopedics or chest clinic.2 Limited number of monitors on a workstation (eg, one or two) for CR/DR presents more of a user interface challenge than for CT or MR, which because of lower inherent spatial resolution can be displayed in multiple windows on the screen. One solution is the ability to view, e.g., CR projection images four on one with instant click full-screen blowup. ED solutions that are deployed today are generally considered satisfactory. It is advantageous to have image display capability in a casting room. One of the most common problems in the ICU environment is the placement of the workstation, of any variety, in a location with high ambient light. Flat panel monitors and CRT displays in general have a lower luminance that transilluminated film on a viewbox. The visual perception of contrast and detail is inversely related to the amount of ambient light. Unfortunately, it is not uncommon to visit ICUs in PACS equipped hospitals and see ICU workstations located next to a bright window. THE DIFFICULT SPECIALTIES
Neurosurgeons often prefer PACS in the operating room.1 Two reasons are that they are used to three-dimensional visualization for planning, and they already have CT and MR guided surgical devices, and are used to operating in this technical environment. While CR and DR have slightly lower spatial resolution than conventional film-screen, enough studies have been done5 that demonstrate comparable accuracy for subtle fractures and other abnormalities, partly because of other visualization and enhancement tools in PACS workstations. Clinical workflow and user interface have been the major challenge for orthopedics. Traditionally most orthopedic clinics have close physical access to a radiographic room (and that continues with PACS), but after the image is exposed the traditional and new paths diverge dramatically, and don’t easily converge back to the point of care (the
BEYOND PACS
433
examination room). It is rare to walk into a traditional orthopedic clinic without at least a small set of viewboxes in each room. Understandably, most orthopedists are concerned about replacing that functionality with a single monitor Web client. In addition, where film once served as the image detector, archive media, and display device, and was physically within the environment as it emerged from a chemical processor, in the PACS clinic, the CR plate is placed in a local reader (or DR device), but the image is transferred to the central PACS server for demographic verification, queuing for hierarchical storage, transferred to accessible PACS RAID storage and Web server RAID cache, before it is available for viewing in the clinic. Unfortunately, many factors can combine to make this process sufficiently slow that clinician and patient are kept waiting. And when the images are available, viewing them on a single monitor Web client may not be considered acceptable. What are reasonable viewing expectations in a clinic? Most clinicians, including surgeons, agree that the most important issues in enterprise acceptance of digital imaging are system reliability,
response time of retrieval, and simple user interface. Image quality is not considered an issue if appropriately sized monitors are provided. SUMMARY
The digital imaging hospital has the potential advantage that imaging studies are available anytime, and anywhere they are needed, with negligible loss. Fulfilling this promise in reality, however, presents challenges as described in this paper. No single best formula for successful deployment exists, since each institution is unique, and its medical staff may have varying preferences. This requires a collaborative team approach to design a solution acceptable to all parties, inside and outside of radiology. We have attempted to identify the significant issues. In addition, hardware and software technology continuously evolve and improve. What is clear is that all institutions will adopt this technology for the reasons described. The successful implementations will be those that are collaboratively and thoughtfully designed. User training of all members of the healthcare team involved with image study access is essential.
REFERENCES 1. Yousem DM, Beauchamp NJ Jr: Clinical input into designing a PACS. J Digit Imaging 13:19-24, 2000 2. Kirsch KR, Brown JA, Geis JR: Clinical acceptance and use of a filmless radiology department in a community hospital. J Digit Imaging 16:45-47, 2003 (suppl 1) 3. Bennett WF, Tunstall KM, Skinner PW, Spigos DG: Delivering images to the operating room: A web-based solution. J Digit Imaging 15:137-139, 2002 (suppl 1)
4. Andriole KP, Avrin DE, Yin L, Gould RG, Arenson RL: PACS Databases and enrichment of the folder manager concept. J Digit Imaging 13:3-12, 2000 5. Slone RM, Muka E, Pilgram TK: Irreversible JPEG compression of digital chest radiographs for primary interpretation: Assessment of visually lossless threshold. Radiology 228:425429, 2003