Telepathology: frozen section diagnosis at a distance

Systematic Review of the Use of Telepathology During Intraoperative Consultation

OBJECTIVE

To compare studies that used telepathology systems vs conventional microscopy for intraoperative consultation (frozen-section) diagnosis.

METHODS

A total of 56 telepathology studies with 13,996 cases in aggregate were identified through database searches.

RESULTS

The concordance of telepathology with the reference standard was generally excellent, with a weighted mean of 96.9%. In comparison, we identified seven studies using conventional intraoperative consultation that showed a weighted mean concordance of 98.3%. Evaluation of the risk of bias showed that most of these studies were low risk.

CONCLUSIONS

Despite limitations such as variation in reporting and publication bias, this systematic review provides strong support for the safety of using telepathology for intraoperative consultations.

Digital pathology is a practical alternative to on-site intraoperative frozen section diagnosis in thoracic surgery

AIMS

Telepathology uses digitised image transfer to allow off-site reporting of histopathology slides. This technology could facilitate the centralisation of pathology services, which may improve their quality and cost-effectiveness. The benefits may be most apparent in frozen section reporting, in which turnaround times (TATs) are vital. We moved from on-site to off-site telepathology reporting of thoracic surgery frozen section specimens in 2016. The aim of this study was to compare TATs before and after this service change.

METHODS AND RESULTS

All thoracic frozen section specimens analysed 4 months prior and 4 months following the service change were included. Demographics, operation, sample type, time taken from theatre, time received by laboratory, time reported by laboratory, TAT, frozen section diagnosis, final histopathological diagnosis and final TNM staging were recorded. The results were analysed with spss statistical software version 24. In total, there were 65 samples from 59 patients; 34 before the change and 31 after the change. Specimens included 51 lung, six lymph node, three bronchial, three chest wall and two pleural biopsies. Before the change, the median TAT was 25 min [interquartile range (IQR) 20-33 min]. No diagnoses were deferred. No diagnoses were changed on subsequent paraffin analysis. After the change, with the use of digital pathology, the median TAT was 27.5 min (IQR 21.75-38.5 min). This difference was not significant (P = 0.581). Diagnosis was deferred in one case (3.23%). There was one (3.23%) mid-case technical failure resulting in the sample having to be transported by courier, resulting in a TAT of 106 min. No diagnoses were changed on subsequent paraffin analysis.

CONCLUSIONS

There was no significant difference in reporting times between digital technology and an on-site service, although one sample was affected by a technical failure requiring physical transportation of the specimen for analysis. Our study was underpowered to detect differences in accuracy.

Making cytological diagnoses on digital images using the iPath network

BACKGROUND

The iPath telemedicine platform Basel is mainly used for histological and cytological consultations, but also serves as a valuable learning tool.

AIM

To study the level of accuracy in making diagnoses based on still images achieved by experienced cytopathologists, to identify limiting factors, and to provide a cytological image series as a learning set.

METHOD

Images from 167 consecutive cytological specimens of different origin were uploaded on the iPath platform and evaluated by four cytopathologists. Only wet-fixed and well-stained specimens were used. The consultants made specific diagnoses and categorized each as benign, suspicious or malignant.

RESULTS

For all consultants, specificity and sensitivity regarding categorized diagnoses were 83-92 and 85-93%, respectively; the overall accuracy was 88-90%. The interobserver agreement was substantial (κ = 0.791). The lowest rate of concordance was achieved in urine and bladder washings and in the identification of benign lesions.

CONCLUSION

Using a digital image set for diagnostic purposes implies that even under optimal conditions the accuracy rate will not exceed to 80-90%, mainly because of lacking supportive immunocytochemical or molecular tests. This limitation does not disqualify digital images for teleconsulting or as a learning aid. The series of images used for the study are open to the public at http://pathorama.wordpress.com/extragenital-cytology-2013/.

The history of pathology informatics: A global perspective

Pathology informatics has evolved to varying levels around the world. The history of pathology informatics in different countries is a tale with many dimensions. At first glance, it is the familiar story of individuals solving problems that arise in their clinical practice to enhance efficiency, better manage (e.g., digitize) laboratory information, as well as exploit emerging information technologies. Under the surface, however, lie powerful resource, regulatory, and societal forces that helped shape our discipline into what it is today. In this monograph, for the first time in the history of our discipline, we collectively perform a global review of the field of pathology informatics. In doing so, we illustrate how general far-reaching trends such as the advent of computers, the Internet and digital imaging have affected pathology informatics in the world at large. Major drivers in the field included the need for pathologists to comply with national standards for health information technology and telepathology applications to meet the scarcity of pathology services and trained people in certain countries. Following trials by a multitude of investigators, not all of them successful, it is apparent that innovation alone did not assure the success of many informatics tools and solutions. Common, ongoing barriers to the widespread adoption of informatics devices include poor information technology infrastructure in undeveloped areas, the cost of technology, and regulatory issues. This review offers a deeper understanding of how pathology informatics historically developed and provides insights into what the promising future might hold.

A static-image telepathology system for dermatopathology consultation in East Africa: the Massachusetts General Hospital Experience

BACKGROUND

The histologic diagnosis of skin lesions in the developing world is complicated by the shortage of pathologists with subspecialty training in dermatopathology, limited access to ancillary diagnostic testing, and costly referrals for expert glass slide consultation in challenging cases.

OBJECTIVE

In this study we evaluate the feasibility of a static-image telepathology platform in Africa for performing accurate dermatopathology consultations.

METHODS

A static-image telepathology platform using the iPath server was utilized by referring pathologists in 4 African hospitals. Diagnostic interpretations were provided by Massachusetts General Hospital dermatopathologists at no cost. The diagnostic accuracy and interobserver correlation was evaluated.

RESULTS

The static histopathologic images were diagnostic in 22 of 29 (76%) cases. Diagnostic accuracy between static image and glass slide diagnosis in 22 cases was 91%, ranging from 86% to 95% according to years of dermatopathology subspecialty expertise. Comparison with the glass slides showed that the telepathology diagnosis was limited by inappropriate field selection in only one case. Interobserver concordance between two pathologists was high (K = 0.86) suggesting that this platform is easy to use with minimal training of both referring and consulting pathologists.

LIMITATIONS

Concordance between conventional microscopy and static image telepathology was performed in 22 of 29 cases for which glass slides were received. Interobserver concordance was performed for two pathologists.

CONCLUSION

Static-image telepathology is a feasible means of rendering diagnoses on dermatopathology cases and is a cost-effective technology for obtaining much-needed second opinions in resource-poor settings.

Primary frozen section diagnosis by robotic microscopy and virtual slide telepathology: the University Health Network experience

Although telepathology (TP) has not been widely implemented for primary frozen section diagnoses, interest in its use is growing as we move into an age of increasing subspecialization and centralization of pathology services. University Health Network is a 3-site academic institution in downtown Toronto. The pathology department is consolidated at its Toronto General Hospital (TGH) site. The Toronto Western Hospital (TWH), located 1 mile to west of TGH, has no on-site pathologist, and generates 5 to 10 frozen section cases per week. More than 95% of these frozen sections are submitted by neurosurgeons, in most cases to confirm the presence of lesional tissue and establish a tissue diagnosis. In 2004, we implemented a robotic microscopy (RM) TP system to cover these frozen sections. In 2006, we changed to a virtual slide (VS) TP system. Between November 2004 and September 2006, 350 primary frozen section diagnoses were made by RM. An additional 633 have been reported by VS TP since October 2006, giving a total of 983 frozen sections from 790 patients. Of these cases, 88% have been single specimens with total turnaround times averaging 19.98 and 15.68 minutes per case by RM and VS TP, respectively (P < .0001). Pathologists required an average of 9.65 minutes to review a slide by RM. This decreased 4-fold to 2.25 minutes after the change to VS TP (P < .00001). Diagnostic accuracy has been 98% with both modalities, and our overall deferral rate has been 7.7%. Midcase technical failure has occurred in 3 cases (0.3%) resulting in a delay, where a pathologist went to TWH to report the frozen section. Discrepant cases have typically involved minor interpretive errors related to tumor type. None of our discrepant TP diagnoses has had clinical impact to date. We have found TP to be reliable and accurate for frozen section diagnoses. In addition to its superior speed and image quality, the VS approach readily facilitates consultation with colleagues on difficult cases. As a result, there has been greater overall pathologist satisfaction with VS TP.

Virtual slide telepathology for an academic teaching hospital surgical pathology quality assurance program

Virtual slide telepathology is an important potential tool for providing re-review of surgical pathology cases as part of a quality assurance program. The University of Arizona pathology faculty has implemented a quality assurance program between 2 university hospitals located 6 miles apart. The flagship hospital, University Medical Center (UMC), in Tucson, AZ, handles approximately 20 000 surgical pathology specimens per year. University Physicians Healthcare Hospital (UPHH) at Kino Campus has one tenth the volume of surgical pathology cases. Whereas UMC is staffed by 10 surgical pathologists, UPHH is staffed daily by a single part-time pathologist on a rotating basis. To provide same-day quality assurance re-reviews of cases, a DMetrix DX-40 ultrarapid virtual slide scanner (DMetrix, Inc, Tucson, AZ) was installed at the UPHH in 2005. Since then, glass slides of new cases of cancer and other difficult cases have been scanned the same day the slides are produced by the UPHH histology laboratory. The pathologist at UPHH generates a provisional written report based on light microscopic examination of the glass slides. At 2:00 pm each day, completed cases from UPHH are re-reviewed by staff pathologists, pathology residents, and medical students at the UMC using the DMetrix Iris virtual slide viewer. The virtual slides are viewed on a 50-in plasma monitor. Results are communicated with the UPHH laboratory by fax. We have analyzed the results of the first 329 consecutive quality assurance cases. There was complete concordance with the original UPHH diagnosis in 302 (91.8%) cases. There were 5 (1.5%) major discrepancies, which would have resulted in different therapy and/or management, and 10 (3.0%) minor discrepancies. In 6 cases (1.8%), the diagnosis was deferred for examination of the glass slides by the reviewing pathologists at UMC, and the diagnosis of another 6 (1.8%) cases were deferred pending additional testing, usually immunohistochemistry. Thus, the quality assurance program found a small number of significant diagnostic discrepancies. We also found that implementation of a virtual slide telepathology quality assurance service improved the job satisfaction of academic subspecialty pathologists assigned to cover on-site surgical pathology services at a small, affiliated university hospital on a rotating part-time basis. These findings should be applicable to some community hospital group practices as well.

Grid technology in tissue-based diagnosis: fundamentals and potential developments

Tissue-based diagnosis still remains the most reliable and specific diagnostic medical procedure. It is involved in all technological developments in medicine and biology and incorporates tools of quite different applications. These range from molecular genetics to image acquisition and recognition algorithms (for image analysis), or from tissue culture to electronic communication services. Grid technology seems to possess all features to efficiently target specific constellations of an individual patient in order to obtain a detailed and accurate diagnosis in providing all relevant information and references. Grid technology can be briefly explained by so-called nodes that are linked together and share certain communication rules in using open standards. The number of nodes can vary as well as their functionality, depending on the needs of a specific user at a given point in time. In the beginning of grid technology, the nodes were used as supercomputers in combining and enhancing the computation power. At present, at least five different Grid functions can be distinguished, that comprise 1) computation services, 2) data services, 3) application services, 4) information services, and 5) knowledge services. The general structures and functions of a Grid are described, and their potential implementation into virtual tissue-based diagnosis is analyzed. As a result Grid technology offers a new dimension to access distributed information and knowledge and to improving the quality in tissue-based diagnosis and therefore improving the medical quality.

Clinical Application of Dynamic Telepathology in Mohs Surgery

BACKGROUND

Telepathology is an expanding technology in multiple fields for remote pathology diagnosis and consultation. The use of telepathology in Mohs surgery has been very limited.

OBJECTIVE

To describe the clinical experience of using a telepathology system for intraoperative consultations on difficult frozen sections during Mohs surgery.

MATERIALS AND METHODS

Intraoperative consultation with a dermatopathologist was obtained using a dynamic telepathology system for all questions arising on frozen sections during Mohs surgery for nonmelanoma skin cancers during a 2-year period.

RESULTS

The most common reason for consultation was to distinguish basal cell carcinoma from a benign histologic simulant on Mohs frozen sections. Other uses included determining tumor histology and distinguishing inflammation from residual tumor.

CONCLUSION

Dynamic telepathology is a useful and convenient adjunct in the Mohs surgery practice for intraoperative consultations on difficult frozen sections.

Digital imaging in pathology: theoretical and practical considerations, and applications

Digital imaging is rapidly replacing photographic prints and Kodachromes for pathology reporting and conference purposes. Advanced systems linked to computers allow greater versatility and speed of turn-around as well as lower costs, allowing the incorporation of macroscopic and microscopic pictures into routine pathology reports and publications. Digital images allow transmission to remote sites via the Internet for primary diagnosis, consultation, quality assurance and educational purposes and can be stored and disseminated in CD-ROMs. Total slide digitisation is now a reality and has the potential to replace glass slides to a large extent. There are extensive applications of digital images in education and research, allowing more objective and automated quantitation of a variety of morphological and immunohistological parameters. Three-dimensional images of gross specimens can be developed and posted on websites for interactive educational programs and preliminary reports indicate that medical vision systems are a reality and can provide for automated computer generated histopathological diagnosis and quality assurance.

Digital imaging applications in anatomic pathology

Digital imaging has progressed at a rapid rate and is likely to eventually replace chemical photography in most areas of professional and amateur digital image acquisition. In pathology, digital microscopy has implications beyond that of taking a photograph. The arguments for adopting this new medium are compelling, and given similar developments in other areas of pathology and radiologic imaging, acceptance of the digital medium should be viewed as a component of the technological evolution of the laboratory. A digital image may be stored, replicated, catalogued, employed for educational purposes, transmitted for further interpretation (telepathology), analyzed for salient features (medical vision/image analysis), or form part of a wider digital healthcare strategy. Despite advances in digital camera technology, good image acquisition still requires good microscope optics and the correct calibration of all system components, something which many neglect. The future of digital imaging in pathology is very promising and new applications in the fields of automated quantification and interpretation are likely to have profound long-term influence on the practice of anatomic pathology. This paper discusses the state of the art of digital imaging in anatomic pathology.

Telepathology: current status and future prospects in diagnostic histopathology

Telepathology is the process of diagnostic histopathology performed on digital images viewed on a display screen rather than by conventional glass slide light microscopy. The technology of telepathology has radically improved over the past 5 years so that it is no longer the limiting factor in the diagnostic process. This review looks at the resources needed for dynamic and static telepathology, including image quality, computers and software interfaces, means of transmission and human resources. It critically analyses 32 published trials of telepathology, including some large prospective studies, in all areas of diagnostic histopathology including intraoperative frozen sections, routine and referral cases. New developments, including internet solutions and virtual microscopy, are described and there is analysis of the economics of telepathology within health care systems. The review concludes that all the necessary technology for telepathology is available, there is strong published evidence for a diagnostic accuracy comparable with glass slide diagnosis, in many contexts there is a clear-cut economic argument in favour of telepathology, and that the technique should now be integrated into mainstream diagnostic histopathology.

Transcontinental communication and quantitative digital histopathology via the Internet; with special reference to prostate neoplasia

OBJECTIVE

To describe practical experiences in the sharing of very large digital data bases of histopathological imagery via the Internet, by investigators working in Europe, North America, and South America.

MATERIALS

Experiences derived from medium power (sampling density 2.4 pixels/microm) and high power (6 pixels/microm) imagery of prostatic tissues, skin shave biopsies, breast lesions, endometrial sections, and colonic lesions. Most of the data included in this paper were from prostate. In particular, 1168 histological images of normal prostate, high grade prostatic intraepithelial neoplasia (PIN), and prostate cancer (PCa) were recorded, archived in an image format developed at the Optical Sciences Center (OSC), University of Arizona, and transmitted to Ancona, Italy, as JPEG (joint photographic experts group) files. Images were downloaded for review using the Internet application FTP (file transfer protocol). The images were then sent from Ancona to other laboratories for additional histopathological review and quantitative analyses. They were viewed using Adobe Photoshop, Paint Shop Pro, and Imaging for Windows. For karyometric analysis full resolution imagery was used, whereas histometric analyses were carried out on JPEG imagery also.

RESULTS

The three applications of the telecommunication system were remote histopathological assessment, remote data acquisition, and selection of material. Typical data volumes for each project ranged from 120 megabytes to one gigabyte, and transmission times were usually less than one hour. There were only negligible transmission errors, and no problem in efficient communication, although real time communication was an exception, because of the time zone differences. As far as the remote histopathological assessment of the prostate was concerned, agreement between the pathologist's electronic diagnosis and the diagnostic label applied to the images by the recording scientist was present in 96.6% of instances. When these images were forwarded to two pathologists, the level of concordance with the reviewing pathologist who originally downloaded the files from Tucson was as high as 97.2% and 98.0%. Initial results of studies made by researchers belonging to our group but located in others laboratories showed the feasibility of making quantitative analysis on the same images.

CONCLUSIONS

These experiences show that diagnostic teleconsultation and quantitative image analyses via the Internet are not only feasible, but practical, and allow a close collaboration between researchers widely separated by geographical distance and analytical resources.

Internet teleconferencing method for telepathology consultations from lung and heart transplant patients

Current Internet-based teleconferencing techniques allow a referring pathologist to transmit real-time images from a microscope to a consultant, while maintaining a verbal conversation using Internet telephony. In our study, 50 randomly selected transbronchial biopsies from lung allograft recipients and 58 randomly selected endomyocardial biopsies from heart transplant patients were diagnosed by consultant pathologists using Internet-based teleconferencing methods. The referring pathologists acquired the real-time video images from the biopsies using a light microscope equipped with a phototube adapter and a video camera. The consultant pathologists viewed the processed images on a video monitor at 800 x 600 resolution, using a standard microcomputer equipped with Netmeeting software, and directed the referring pathologist to move the slide under the microscopy and/or change image magnification. The validity of telepathology diagnoses was assessed with kappa coefficients. Consultations were completed in 5 to 15 minutes per case. Sound transmission was unreliable, and in approximately 25% of consultations the referring pathologist needed to "call back" to reestablish verbal communication. In all but 2 transbronchial biopsies there was agreement between the original diagnosis and the diagnosis by telepathology (kappa = 0.92). In 48 of 58 endomyocardial biopsies there was concordance between the 2 diagnoses (kappa = 0.692). Only 3 out of 10 of these discrepancies were clinically significant (kappa = 0.897). Internet-based teleconferencing techniques provide effective and relatively inexpensive tools for real time telepathology consultations. The technology is probably best suited for the study of small specimens from patients that require rapid diagnosis by a consultant.

Telepathology in a routine clinical environment: implementation and accuracy of diagnosis by robotic microscopy in a one-stop breast clinic

The concept of using telepathology as a way of increasing the efficiency of pathologists is not new. There have been many studies attempting to evaluate the role of telepathology diagnosis, predominantly using transmission of still digital images. This study evaluates the potential value of remote diagnosis using robotic microscopy in the setting of a one-stop breast clinic. A Zeiss Axiopath telepathology system was used. The aim was to identify deficiencies in software and the minimum specifications for the computer hardware and network capability needed for reproducible pathological diagnosis with a view to developing a system that can preclude the need for an on-site pathologist. Forty-seven fine needle aspiration smears were diagnosed simultaneously by a pathologist in the breast clinic and by a different pathologist operating a robotic microscope situated in the clinic in a different wing of the hospital from the pathology department. The diagnoses, the time taken for clinic and remote diagnosis, and difficulties in using the system were recorded. Absolute correlation was achieved in 80.9% of cases. There was one false-positive diagnosis of cancer and no false negatives. The mean time taken for diagnosis per case was 2.39 min in clinic and 10.81 min by remote control robotic microscopy. However, as the pathologist did not have to leave the department, remote diagnosis was overall more economical of pathologists' time. Image quality was generally found to be good and not an obstacle to diagnosis. There were operational and technical problems that made remote diagnosis tedious and lengthy. Although at present the system is not capable of replacing an on-site pathologist, the results were encouraging and suggest that remote control remote diagnosis has the potential to increase the efficiency of pathologists.

Telemicroscopy by the Internet revisited

This paper reports a fundamentally new concept for internet-based telemicroscopy. By separating a telemicroscopy application into three tasks - microscope control program, external server, and client application - it is possible to establish a telemicroscopy session between two arbitrary end points on the Internet even if both of the end points are secured by firewall (microscope and client application). The advantages of such a distributed system, compared with the classical point-to-point systems, are discussed. The telemicroscopy system is combined with a telepathology database, which is capable of automatically recording telemicroscopy sessions, allowing a convenient combination of interactive remote microscopy and store and forward telepathology. In addition to remote primary diagnosis, it is easily possible to discuss difficult cases within dedicated user groups, no matter whether images originate from a telemicroscopy session, or are manually entered into the database.

Telepathology overview: from concept to implementation

Telepathology is the practice of pathology at a distance by using video imaging and telecommunications. Significant progress has been made in telepathology. To date, 12 classes of telepathology systems have been engineered. Rapid and ultrarapid virtual slide processors may further expand the range of telepathology applications. Next-generation digital imaging light microscopes, such as miniaturized microscope arrays (MMA), may make virtual slide processing a routine laboratory tool. Diagnostic accuracy of telepathology is comparable with that of conventional light microscopy for most diagnoses. Current telepathology applications include intraoperative frozen sections services, routine surgical pathology services, second opinions, and subspecialty consultations. Three telepathology practice models are discussed: the subspecialty practice (SSP) model; the case triage practice (CTP) model; and the virtual group practice (VGP) model. Human factors influence performance with telepathology. Experience with 500 telepathology cases from multiple organs significantly reduces the video viewing time per case (P < .01). Many technology innovations can be represented as S-curves. After long incubation periods, technology use and/or efficiency may accelerate. Telepathology appears to be following an S-curve for a technical innovation.

Telepathology networking in VISN-12 of the Veterans Health Administration

The Veterans Integrated Service Network (VISN)-12, headquartered in Chicago, has implemented a telepathology network between the eight VISN-12 hospital laboratories and Loyola University Medical School linked by an economical, high-speed wide-area network (WAN). Implementation of the WAN has reduced monthly telecommunications costs in VISN-12 by approximately 67%. In addition to telepathology, the WAN enables real-time teleradiology (general, computer tomography, and ultrasound), telefluoroscopy, telenuclear medicine imaging, telepsychiatry, and other forms of teleconsultation. Current applications of telepathology in VISN-12 include: primary diagnosis and consultation in surgical pathology, interpretation of serum protein electrophoresis and immunofixation gels, provision of support for consolidated microbiology laboratories, review of problematic peripheral blood smears, and distance learning. We have learned a variety of lessons from telepathology. The enthusiasm and technical skill of providers are essential for success. As well, frequent communication and rapid technical support are necessary. Finally, in a supportive environment, telepathology is a tool that can help bring together clinical laboratories with shared missions and goals.

Routine surgical telepathology in the Department of Veterans Affairs: experience-related improvements in pathologist performance in 2200 cases

OBJECTIVE

To determine whether diagnostic concordance, case deferral rate, and/or time required to review slides changed significantly as telepathologists gained additional experience using a hybrid dynamic/store-and-forward (HDSF) telepathology (TP) system on the 2000 cases following an initial 200 consecutive surgical cases, previously reported.

MATERIALS AND METHODS

Gross surgical pathology specimens were prepared by specially trained personnel in Iron Mountain, Michigan. For TP, glass slides were placed on the stage of a robotic microscope at the Iron Mountain VAMC (remote site); control of the motorized microscope was then transferred to a pathologist located 220 miles away at the Milwaukee, Wisconsin, VAMC (host site). For each case, a telepathologist had the option of either rendering a diagnosis or deferring the case for later analysis by conventional light microscopy (LM). After the slides were read by TP and a surgical pathology report had been generated (for nondeferred cases), the slides were transported to Milwaukee, where they were reexamined by the same pathologist, now using LM. When there was disagreement between the TP and LM diagnosis, a supplemental or revised report was issued, and the referring physician was notified by telephone immediately. All supplemental and revised reports were reviewed by a third pathologist in the group. The slides were then reviewed by the pathology group practice or, when there was no consensus, by the Armed Forces Institute of Pathology to establish a "truth" diagnosis. To determine changes in telepathologist performance with experience after the initial start-up of the service, their performance in handling 10 consecutive sets of 200 surgical pathology cases was analyzed.

RESULTS

Concordance rates for clinically significant TP and LM diagnoses were high for all 10 sets, ranging from 99% to 100%. Comparing the first set (Cases 201-400) with the last set (Cases 2001-2200), viewing times per case were reduced from 10.26 min to 3. 58 min. Viewing times per slide were reduced from 3.44 min to 1.13 min per slide, comparing the first and last sets. Case turnaround times (TAT) decreased from 2.46 days to < or =1.5 days.

CONCLUSION

Thes results demonstrate that improvements in TP services occur over time as the result of additional experience using the TP system. The high diagnostic concordance and low rate of case deferral lend additional support to the proposal that a host-site pathologist using HDSF TP can substitute effectively for an on-site pathologist as a service provider.

Telepathology by the Internet

A new concept for telemicroscopy has recently been introduced using the Internet and conventional web browser, with Java support for microscope remote control as well as image transfer and discussion (http://amba.charite.de/telemic/). The system has two major components: the telemicroscopy server, which is a computer with Internet access connected to the automatic microscope, and the telemicroscopy client, who remotely operates the microscope. This simplified telemicroscopy system allows any Internet user to become a consultant for telepathology without the acquisition of specialized hardware or software. For the inquirer seeking advice, however, this solution is still very expensive, since it requires a fully automated microscope. The present study describes a system that can be used for conventional microscopes. A video camera mounted on a microscope with a photo tube is connected to the frame grabber of a PC. Java-based telemicroscopy software transforms the computer into an Internet server, which automatically distributes new microscope images, after manual operations, to all connected clients. Any Internet user can access the web page of the server to become a telemicroscopy client. A Chat function allows for the online exchange of written text and a Discuss function enables the mouse button to display an arrow to all connected clients, which highlights distinct structures of the images. The system was optimized for simplicity, while presenting all features that are necessary to show and discuss difficult cases with any expert in the field who has Internet access. It offers new perspectives for telepathology and it is envisaged that many pathologists and scientists will use this facility to connect their personal microscopes to the Internet, forming a network for teleconsultation. To foster this development, the software described in this paper is being made freely available. Hopefully, this development will promote communication between pathologists and may thus increase the quality of diagnosis. Information on inquiry and installation of the software is available at the website mentioned above. Telemicroscopy sessions using the Telemic version for conventional microscopes can be scheduled by contacting the authors by e-mail (iver. petersen@charite.de).

Use of telepathology for routine surgical pathology review in a test bed in the Department of Veterans Affairs

BACKGROUND

Routine surgical pathology review by telepathology could be an important service component of multi-institutional pathology laboratory systems. Such service networks would increase access for rural hospitals without on-site pathologists to a broader range of pathology services on a daily basis.

METHODS

In this clinical trial, we analyzed the diagnostic accuracy, deferral rates, and viewing times of two generalist pathologists using a hybrid dynamic/store-and-forward (HDSF) telepathology (TP) system to render diagnoses in real time on 200 consecutive surgical cases. The objective was to assess the efficacy of TP in providing diagnostic surgical pathology services to a remote hospital without an onsite pathologist. Surgical pathology specimens underwent gross preparation by specially trained personnel. When appropriate, this was done under the video supervision of a telepathologist. For TP, glass slides were placed on the stage of a robotic microscope at the Iron Mountain (MI) Department of Veterans Affairs Medical Center (VAMC) (remote site); control of the motorized microscope was then transferred to a pathologist located 220 miles away at the Milwaukee VAMC (host site). For each case, the telepathologist had the option of rendering a diagnosis or deferring the case for later analysis by conventional light microscopy (LM). After the slides were read by TP and a surgical pathology report had been generated, the slides were transported to Milwaukee, where they were reexamined by the telepathologist using LM and then by the pathology group practice or, when there was no consensus, by an outside consultant to establish a "truth" diagnosis.

RESULTS

Compared with the consensus ("truth") diagnosis, clinically important and overall concordance were 99.0% and 97.4%, respectively, by TP, and clinically important and overall concordance were 100.0% and 98.5%, respectively, by LM. The deferral rate was 2.5%. Examining glass slides by HDSF telepathology took an average of 4.43 minutes per slide and 12.09 minutes per case.

CONCLUSION

The high diagnostic accuracy and low rate of case deferral support the proposal that an offsite pathologist using HDSF telepathology can substitute effectively for an onsite pathologist as a service provider.

Telemicrobiology: feasibility study

BACKGROUND

Rural hospitals generally lack staffing with infectious disease specialists or pathologists. Without on-site pathologists, the range of microbiology services offered by clinical laboratories may be limited as well.

OBJECTIVE

To study the feasibility of using static-image telepathology to evaluate Gram stains of microbiologic preparations.

MATERIALS AND METHODS

In this retrospective feasibility study, three pathologists evaluated Gram stains of slides from 50 cases by two viewing modalities: static-image telepathology and conventional light microscopy. Digital video images of slides were captured at two magnifications (using 40x and 100x objective lenses) at 1024 x 768 x 24-bit color and transmitted over standard telephone lines at 14,400 kbps. Pathology reports and culture results served as "truth diagnoses." Categories of interpretations were correct, minor discrepancy, or major discrepancy with regard to the implications for patient care.

RESULTS

The diagnostic accuracy of video image readings and conventional light microscopy readings were nearly identical, with no statistically significant differences in the performances of specialty and nonspecialty pathologists (P > 0.05). The mean accuracies of readings of the video images and light microscopy images were 95.3% and 95.4%, respectively. Taking into account the time required by a referring pathologist to capture video digital images, telemicrobiology was somewhat less efficient than conventional light microscopy.

CONCLUSIONS

Pathologists can accurately evaluate digital video images of preselected fields on Gram-stained slides. In clinical practice, however, a limiting factor may be the availability of local personnel qualified to select the microscopic fields for evaluation by telepathologists. The adequacy of the video images suggests that telepathology may also be used for remote supervision of quality assurance programs in microbiology laboratories, as well as for remote proficiency training of laboratory personnel.

Diagnostic accuracy of a rural live video telepathology system

Accuracy of diagnoses rendered using a live video telepathology network was assessed for permanent sections of surgical pathology specimens. To determine accuracy, telepathology diagnoses were compared with those obtained by directly viewing the glass slide using a standard microscope. A total of 294 cases were read via both telepathology and glass slide by attending pathologists at a tertiary care medical center. Overall accuracy was defined as exact concordance between diagnoses. Clinically insignificant differences in diagnoses were excluded to determine clinically significant accuracy. For the 285 cases with complete data, the overall accuracy for telepathology was 0.912 (95% confidence interval [CI], 0.872-0.941), whereas the overall accuracy for glass slide readings was 0.968 (95% CI, 0.939-0.985). This difference is statistically significant (p = 0.009). When focusing on clinically significant discrepancies, where the difference in diagnosis might affect therapeutic decisions, the video accuracy was only slightly less than the glass slide accuracy (0.965 [95% CI, 0.934-0.982] vs. 0.982 [95% CI, 0.957-0.994], respectively), but this difference is not statistically significant (p = 0.302). Most of the cases with clinically significant differences involved lesions with inherently high interobserver variation. Certainty of diagnosis did not differ between video and glass slide readings (p = 0.911), but there was an association between certainty of diagnosis and diagnostic accuracy for video (p = 0.003 for clinically significant accuracies). Based on these findings, we recommend when using this telepathology system that only preliminary diagnoses should be given in the following situations: for diagnostic areas with known high interobserver variability; when the consultant has any degree of uncertainty about the presence or absence of the lesion in question; and when there is insufficient experience using telepathology as a diagnostic medium.

Static image analysis of skin specimens: the application of telepathology to frozen section evaluation

Although the ability to transmit high-resolution images of histopathological sections could have a profound impact on the practice of pathology, the application of video microscopy to the daily activities of surgical pathology has not been rigorously evaluated. In particular, certain aspects of video microscopy relating to frozen section evaluation have not been adequately assessed. We conducted a retrospective analysis of 48 excisional skin biopsy specimens encompassing a spectrum of benign and malignant lesions. To simulate an actual frozen section evaluation, only original frozen section slides were evaluated. Fields were selected and digitized (Roche Image Analysis System) by a pathology resident. Two sets of diagnoses were subsequently rendered by a surgical pathologist, the first set based on the digitized images and the second based on direct microscopic examination of the histological slides. The two sets of diagnoses were compared, and the concordance rates were as follows: malignant diagnoses, 100%; benign diagnoses, 100%; positive margins, 96%; negative margins, 99%. One (4%) of the 25 positive margins was indexed as negative by image analysis. Conversely, one (1%) of the 121 negative margins was indexed as positive by image analysis. In both of these cases, error was attributable to selection and digitization of an inappropriate field. We conclude that telepathology of static images is an accurate method of evaluating frozen sections of skin lesions. Potentially, this technology could be applied to the frozen section evaluation of other lesions as well. Static image analysis is, however, susceptible to errors induced by inappropriate field selection, emphasizing the need for trained and skillful personnel on both sides of the video camera.

Diagnostic accuracy of an international static-imaging telepathology consultation service

Static-image and dynamic- (real-time) image telepathology are competing technologies. Although some studies suggest that the diagnostic accuracy of the dynamic-image telepathology approaches the accuracy of light microscopy, few reports have documented the diagnostic accuracy of static-image telepathology as used in the setting of an actual surgical pathology consultation practice. We report the results of an analysis of 171 telepathology consultation cases submitted to the Arizona-International Telemedicine Network (AITN). Digital images were submitted by pathologists from six participating institutions in Arizona, Mexico, and China. Telepathologists could render a telepathology diagnosis (TP) or defer rendering a diagnosis to obtain additional video images, glass slides for detailed analysis, or to obtain tissue blocks for special studies such as immunohistochemistry. The telepathologists rendered diagnoses for 144 cases and deferred 27 cases. Two pathologists retrospectively evaluated-glass slides from each case and rendered a consensus glass slide (GS) "truth" diagnosis. There was 88.2% concordance between TP and GS diagnoses (127 of 144 diagnoses). Concordance of 96.5% was achieved for clinically important diagnoses (139 of 144 diagnoses). Telepathologists deferred making a diagnosis to obtain glass slides for conventional light microscopy in 14 cases (8.1%) and for results of immunohistochemistry studies in 13 cases (7.6%). Thus, correct diagnoses were rendered by static-image telepathology in 127 of 171 cases (74.3%) at the time of telepathology diagnostic sessions. Inappropriate field selection and sampling biases of referring pathologists, as well as a tendency of static-image telepathologists to underestimate the complexity of some cases, may reduce the value of consultations based on the viewing of static images.

Frozen-section services by telepathology: experience of 100 cases in the San-in District, Japan

The early experience is reported here of the use of intra-operative frozen-section service by telepathology using the integrated Service Digital Network (ISDN), a commercially available system that is being connected between the Department of Pathology of Tottori University and Matsue City Hospital, a distance of 30 km. The transfer rate is currently 64 kbit/s. The frozen-section service was conducted for a total of 117 tissue specimens (organs) from 100 patients between August 1993 and May 1995. The average time taken for examination of each specimen of frozen section was 13 min, ranging between 2 and 42 min. The average number of transmitted images was 6.2. Six cases necessitated more than 11 transmitted images to make a diagnosis, while 13 cases could be diagnosed from two images only. Correct and permissible diagnoses were obtained in 109 (93.2%) out of 117 specimens when comparing the telepathology diagnosis with that of direct microscopy. Improper or misdiagnosis was made for eight cases (specimens), which were misinterpreted as papillary carcinoma in Basedow's disease, adenoma and hyperplasia in two pheochromocytomas, solid-tubular carcinoma in phyllodes tumor, mastopathy in invasive carcinoma, metastatic carcinoma in astrocytoma, follicular lymphoma in reactive hyperplasia, and lymphadenitis in follicular lymphoma. In retrospect, diagnosis of these cases should have been deferred. From the results, it was concluded that the intraoperative frozen-section service by telepathology may be a worthwhile substitute for hospitals with limited accessibility to local pathology service, in spite of pitfalls in some cases. Well prepared, high-quality frozen section, sufficient verbal communication with surgeons, and a rather conservative attitude on the part of a well-trained pathologist seem to be the essential ingredients for reaching an accurate decision when using telepathology.

Methods in quantitative image analysis

The main steps of image analysis are image capturing, image storage (compression), correcting imaging defects (e.g. non-uniform illumination, electronic-noise, glare effect), image enhancement, segmentation of objects in the image and image measurements. Digitisation is made by a camera. The most modern types include a frame-grabber, converting the analog-to-digital signal into digital (numerical) information. The numerical information consists of the grey values describing the brightness of every point within the image, named a pixel. The information is stored in bits. Eight bits are summarised in one byte. Therefore, grey values can have a value between 0 and 256 (2(8)). The human eye seems to be quite content with a display of 5-bit images (corresponding to 64 different grey values). In a digitised image, the pixel grey values can vary within regions that are uniform in the original scene: the image is noisy. The noise is mainly manifested in the background of the image. For an optimal discrimination between different objects or features in an image, uniformity of illumination in the whole image is required. These defects can be minimised by shading correction [subtraction of a background (white) image from the original image, pixel per pixel, or division of the original image by the background image]. The brightness of an image represented by its grey values can be analysed for every single pixel or for a group of pixels. The most frequently used pixel-based image descriptors are optical density, integrated optical density, the histogram of the grey values, mean grey value and entropy. The distribution of the grey values existing within an image is one of the most important characteristics of the image. However, the histogram gives no information about the texture of the image. The simplest way to improve the contrast of an image is to expand the brightness scale by spreading the histogram out to the full available range. Rules for transforming the grey value histogram of an existing image (input image) into a new grey value histogram (output image) are most quickly handled by a look-up table (LUT). The histogram of an image can be influenced by gain, offset and gamma of the camera. Gain defines the voltage range, offset defines the reference voltage and gamma the slope of the regression line between the light intensity and the voltage of the camera. A very important descriptor of neighbourhood relations in an image is the co-occurrence matrix. The distance between the pixels (original pixel and its neighbouring pixel) can influence the various parameters calculated from the co-occurrence matrix. The main goals of image enhancement are elimination of surface roughness in an image (smoothing), correction of defects (e.g. noise), extraction of edges, identification of points, strengthening texture elements and improving contrast. In enhancement, two types of operations can be distinguished: pixel-based (point operations) and neighbourhood-based (matrix operations). The most important pixel-based operations are linear stretching of grey values, application of pre-stored LUTs and histogram equalisation. The neighbourhood-based operations work with so-called filters. These are organising elements with an original or initial point in their centre. Filters can be used to accentuate or to suppress specific structures within the image. Filters can work either in the spatial or in the frequency domain. The method used for analysing alterations of grey value intensities in the frequency domain is the Hartley transform. Filter operations in the spatial domain can be based on averaging or ranking the grey values occurring in the organising element. The most important filters, which are usually applied, are the Gaussian filter and the Laplace filter (both averaging filters), and the median filter, the top hat filter and the range operator (all ranking filters). Segmentation of objects is traditionally based on threshold grey values. (AB