Telepathology with an integrated services digital network--a new tool for image transfer in surgical pathology: a preliminary report

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.

Image standards in tissue-based diagnosis (diagnostic surgical pathology)

Background

Progress in automated image analysis, virtual microscopy, hospital information systems, and interdisciplinary data exchange require image standards to be applied in tissue-based diagnosis.

Aims

To describe the theoretical background, practical experiences and comparable solutions in other medical fields to promote image standards applicable for diagnostic pathology.

Theory and experiences

Images used in tissue-based diagnosis present with pathology – specific characteristics. It seems appropriate to discuss their characteristics and potential standardization in relation to the levels of hierarchy in which they appear. All levels can be divided into legal, medical, and technological properties. Standards applied to the first level include regulations or aims to be fulfilled. In legal properties, they have to regulate features of privacy, image documentation, transmission, and presentation; in medical properties, features of disease – image combination, human – diagnostics, automated information extraction, archive retrieval and access; and in technological properties features of image acquisition, display, formats, transfer speed, safety, and system dynamics. The next lower second level has to implement the prescriptions of the upper one, i.e. describe how they are implemented. Legal aspects should demand secure encryption for privacy of all patient related data, image archives that include all images used for diagnostics for a period of 10 years at minimum, accurate annotations of dates and viewing, and precise hardware and software information. Medical aspects should demand standardized patients' files such as DICOM 3 or HL 7 including history and previous examinations, information of image display hardware and software, of image resolution and fields of view, of relation between sizes of biological objects and image sizes, and of access to archives and retrieval. Technological aspects should deal with image acquisition systems (resolution, colour temperature, focus, brightness, and quality evaluation procedures), display resolution data, implemented image formats, storage, cycle frequency, backup procedures, operation system, and external system accessibility. The lowest third level describes the permitted limits and threshold in detail. At present, an applicable standard including all mentioned features does not exist to our knowledge; some aspects can be taken from radiological standards (PACS, DICOM 3); others require specific solutions or are not covered yet.

Conclusion

The progress in virtual microscopy and application of artificial intelligence (AI) in tissue-based diagnosis demands fast preparation and implementation of an internationally acceptable standard. The described hierarchic order as well as analytic investigation in all potentially necessary aspects and details offers an appropriate tool to specifically determine standardized requirements.

The iPath telemedicine platform

An early, point-to-point telepathology system at the University of Basel developed into an open-source, Internet-based platform for telemedicine in 2001. The Internet Pathology Suite (iPath) is a Web-based telepathology platform that permits the online presentation and discussion of cases within user groups. It also allows realtime telemicroscopy across firewalls. After four years, the telepathology network has over 700 active users. More than 6,300 cases with a total of about 39,000 images have been diagnosed. The diagnostic workload of all these cases is not exclusively handled by the Department of Pathology in Basel, but by a growing number of independent groups who also use the server simply as a case repository. What started as a small project for hospitals in Switzerland has become a global network.

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.

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.

Digital image documentation for quality assessment

OBJECTIVE

To demonstrate the feasibility of the use of digital images to document routine cases and to perform diagnostic quality assessment.

METHODS

Pathologists documented cases by acquiring up to 12 digital images per case. The images were sampled at 25:1, 50:1, 100:1, 200:1, or 400:1 magnifications, according to adequacy in aiding diagnosis. After each acquisition, the referral pathologist marked a region of interest within each acquired image in order to evaluate intrinsic redundancy. The extrinsic redundancy was determined by counting the unnecessary images. Cases were randomly selected and reviewed by one pathologist. The quality of each image, the possibility of accomplishing a diagnosis based on images, and the degree of agreement was evaluated.

RESULTS

During routine practice, 1469 cases were documented using 3902 images. Most of the images were acquired at higher power magnifications. From all acquired cases, 143 cases and their 373 related images were randomly selected for review. In 88.1% (126/143) of reviewed cases, it was possible to accomplish the diagnosis based on images. In 30.2% (38/126) of these cases, the reviewer considered that the diagnosis could be accomplished with fewer images. The referral pathologist and the reviewer found intrinsic redundancy in 57.8% and 54.5% of images, respectively.

CONCLUSIONS

Our results showed that digital image documentation to perform diagnostic quality assessment is a feasible solution. However, owing to the impact on routine practice, guidelines for acquisition and documentation of cases may be needed.

An experimental inter-expert telepathology network using static imaging

AIMS

To set up a network for remote consultation using static imaging telepathology via Internet connection between pathologists in different European countries, and to collect some numerical and subjective impressions on the usefulness of this form of telepathology.

METHODS

A static image remote consultation network between 11 pathologists in nine European countries was set up; all pathologists were equipped with the same telepathology system. The pathologists formed three subject oriented subgroups concerned with prostate, melanoma, and soft tissue sarcoma pathology. Each pathologist sent and received a small number of cases, and data on each case were collected and analysed. The whole experiment was controlled through a World Wide Web site.

RESULTS

A total of 56 case consultations on 34 different cases were exchanged. The average case document contained seven images, and contained 1.97 Mbytes of data. For cases in which data were recorded, average case preparation and remote consultation time was 55 minutes and 9.2 minutes, respectively. Transmission times averaged 3.9 minutes. In subjective impressions, reservations were expressed in several cases regarding the confidence that could be given to the diagnosis from the images presented.

CONCLUSIONS

Remote consultation by telepathology via the Internet is now technically feasible and reasonably user friendly, but is only suitable as a method of disease diagnosis in some cases.

Intra-hospital use of a telepathology system

Utilization of telepathology systems to cover distant geographical areas has increased recently. However, the potential usefulness of similar systems for closer distances does not seem to be widely appreciated. In this study, we present data on the use of a simple telepathology system connecting the pathology department and the intra-operative consultation room within the operating theaters of the hospital. Ninety-eight frozen section cases from a past period have been re-evaluated using a real-time setup. Forty-eight of the cases have been re-evaluated in the customary fashion; allowing both ends to communicate and cooperate freely. Fifty of the cases, however, were evaluated by the consultant while the operating room end behaved like a robot; moving the stage of the microscope, changing and focusing the objectives. The deferral rate was lower than the original frozen section evaluations. Overall, the sensitivity was 100%, specificity 98%, negative predictive value 96, 5% and positive predictive value 100%. No significant difference was found for the diagnostic performances between the cooperative and robotic simulation methods.Our results strengthen the belief that telepathology is a valuable tool in offering pathology services to remote areas. The far side of a hospital building can also be a remote area and a low cost system can be helpful for intraoperative consultations. Educational value of such a system is also commendable.

Competence on demand in DNA image cytometry

Quantitation methods in clinical pathology have to be normalized and standardized both from the instrumental and the methodological point of view to guarantee a defined level of precision and accuracy independent of the site where they are applied. The comparability of results obtained in different laboratories is the basis for the application of standardized diagnostic classification systems and therapeutic schemes. Remote quantitation based on standardized evaluation tools could be a way to reach the goals mentioned above. Diagnostic DNA image cytometry, increasingly used as a routine method in clinical pathology, will serve as an example for demonstrating the feasibility and usefulness of a concept of remote quantitation. We report a system for a remote DNA ploidy analysis, based on client server technology, and accessible via Internet or ISDN connections (Quantitation Server EUROQUANT). This system (i) allows the cytometric measurement of the DNA content of cells for diagnostic purposes, (ii) provides the user with comprehensive quality control of such measurements, (iii) helps in trouble-shooting, and (iv) gives assistance in diagnostic interpretation. The system uses the principles of telepathology and Internet technology. To date, more than 40 laboratories from Europe, USA, and Asia have successfully performed analyses on about 3,000 ploidy data sets.

Detection of retinal lesions after telemedicine transmission of digital images

PURPOSE/BACKGROUND

To assess whether loss of image resolution or colour and subsequent telemedicine transmission of digital images affects the accuracy of retinal lesion detection by ophthalmologists when compared with the original transparencies.

METHODS

Fifteen ophthalmologists of different experience independently scored 11 retinal images for pathological signs. The images were presented as either transparencies or colour and monochrome digital images, which had been transmitted via telephone lines to a geographically remote location. One patient's eye was also imaged using scanning laser ophthalmosocopy (SLO) which produced a dynamic black and white digital image. ANOVA analysis was performed.

RESULTS

Total scores were higher for transparencies than colour (p = 0.0003) or black and white digital images (p = 0.00006). Expert observers (n = 5) considered separately showed no significant difference of accuracy between transparencies and either colour digital (p = 0.09) or monochrome digital images (p = 0.11). Experts were better than trainees at detecting pathology from less familiar images: total score (p = 0.02), colour digital (p = 0.03), monochrome digital (p = 0.02) and SLO images (p = 0.004).

CONCLUSION

Experienced observers can identify sight-threatening retinal pathology from poorer-resolution digital images that have been transmitted by telemedicine. They can also adapt to viewing less familiar images such as black and white digital or SLO images.

"Virtual microscopy" and the internet as telepathology consultation tools: diagnostic accuracy in evaluating melanocytic skin lesions

The Internet offers a widely available, inexpensive tool for telepathology consultations. It allows the transfer of image and text files through electronic mail (e-mail) or file transfer protocols (FTP), using a variety of microcomputer platforms. We studied the use of the Internet and "virtual microscopy" tools for the diagnosis of 35 skin biopsies, including a variety of benign and malignant melanocytic lesions. Digitized images from these lesions were obtained at 40x and 100x optical magnification, using a high resolution digital camera (Microlumina, Leaf Systems, Southborough, MA), a light microscope with a phototube adapter and a microcomputer with a Pentium 166 MHz microprocessor. Two to four images of each case were arranged on a "canvas" to represent the majority or an entire biopsy level, using Photoshop software (Adobe Systems Inc., San Jose, CA). The images were compressed using Joint Photographers Expert Group (JPEG) format. The images were then viewed on a computer video monitor in a manner that closely resembles light microscopy, including scrolling by using the "hand tool" of Photoshop and changing magnification digitally up to 4 times without visible image degradation. The image files, ranging in size from 700 kilobytes to 2.1 megabytes (average 1.6 megabytes) were attached to e-mail messages that contained clinical information, using standard Multipurpose Internet Mail Extension (MIME) protocols and sent through the Internet, for interpretation by a dermatopathologist. The consultant could open the images from the e-mail message, using Microsoft Outlook Express (Microsoft Corp., Redmond, WA) and Photoshop software, scroll them, change magnification and render a diagnosis in a manner that closely simulates light microscopy. One hundred percent concordance was obtained between the telepathology and traditional hematoxylin and eosin slide diagnoses. The Internet and relatively inexpensive "virtual microscopy" tools offer a novel technology for dermatopathology consultations. Potential applications of this technology to pathology and technical problems posed by the use of an open, widely distributed network to share sensitive medical information are discussed.

Case triage model for the practice of telepathology

OBJECTIVE

To implement and evaluate a practice model for telepathology.

METHODS

A case triage practice model was devised in which general pathologists review all cases and refer them to subspecialists only when necessary. In 1993, the Arizona-International Telemedicine Network (AITN), a high-resolution static imaging telepathology diagnostic network, linking six sites to the University of Arizona in Tucson, began testing the model. Work flow through the network was analyzed, and diagnostic concordance was assessed in 150 surgical cases by comparing the diagnoses of the referring (transmitting) pathologists with diagnoses of the consulting (receiving) telepathologists as well as by comparing the referring pathologists' diagnoses with the consensus diagnoses reached by an independent review panel. Data analysis was controlled for subspecialty case type. Telepathologists had access to the referring pathologists' preliminary diagnoses, and the review panel had access to the original glass slides and the surgical pathology reports prior to rendering their respective diagnoses.

RESULTS

The triage pathologist completed the telepathology consultation without the assistance of a subspecialty pathologist in 66% of the cases. The review panel examined the original glass slides from 134 cases by light microscopy. Concordance rates of the telepathologists' or review panel's diagnoses with the referring pathologists' diagnoses were not statistically different (93.1% v 83.6%, respectively; P > 0.05).

CONCLUSION

The case triage model is suitable for the practice of telepathology. It significantly reduces the need for subspecialty pathologists. Static imaging telepathology is useful and reasonably efficient for rendering diagnostic opinions in the majority of referred cases. Tissue sampling limitations imposed by static imaging occasionally resulted in diagnostic errors.

Dermatopathology via a still-image telemedicine system: diagnostic concordance with direct microscopy

OBJECTIVE

To determine the concordance of dermatopathology diagnosis by still-image telemedicine technology and direct microscopy.

MATERIALS AND METHODS

Skin specimens (N = 79) were examined by a dermatopathologist using a still-image phone system, and the diagnoses were compared with those made by the same dermatopathologist 1 year earlier by direct microscopy. The telemedical diagnoses were reached first without, and then with, patient histories.

RESULTS

When the patient history was available, identical diagnoses were made in 66 of the 79 cases (84% concordance rate). Without patient history, the concordance rate was 80%. The diagnostic concordance rate for the diagnosis of benign nevocytic nevi, inflammatory diseases, and benign and malignant non-squamous cell carcinoma neoplasms was statistically significantly greater than the concordance rate for the diagnosis of squamous cell carcinoma and squamous cell carcinoma in situ (P = 0.005).

CONCLUSIONS

The diagnostic concordance rate achieved by teledermatopathology using a still-image phone system fell short of the 99% intraobserver diagnostic concordance rate using direct microscopy.

Accuracy of interpretation of microscopic images of cytologic, hematologic, and histologic specimens using a low-resolution desktop video conferencing system

OBJECTIVE

To determine the accuracy of interpretation of microscopic images for pathologic study transmitted over Switched-56 lines using a desktop interactive video conferencing system.

MATERIALS AND METHODS

In subjective studies, two systems were connected using null-modem cables, which allowed evaluation of different bandwidths from 56 kbps to 384 kbps. Objective studies were done with two systems connected at distant sites via paired Switched-56 lines that produced an effective bandwidth of 112 kbps. A video camera mounted on a microscope was attached to the sending system. The resolution of the video image on the video conferencing system was 352 x 288 lines. Cases for cytology, hematology, and histopathology studies were selected from archives; one pathologist transmitted microscopic images, and a second pathologist made interpretations. The three pathologists were Board certified with similar experience that ranged from 20 to 35 years. Categories of interpretations or observations were predetermined for each study to allow the data on agreement between the direct microscopic interpretation or observation and that recorded by the receiving pathologist to be corrected for agreement attributable to chance alone. The results were analyzed using the kappa statistic.

RESULTS

In the subjective studies, image degradation prevented interpretation while the microscope stage was moved. This problem occurred at all bandwidths tested. Image quality limited microscopic details. Organisms < 1 micron in diameter could not be seen reliably. In objective cytologic studies, overall agreement was recorded on 89 of 99 observations. In the four categories of specimens, observed agreement ranged from 0.778 to 0.958, and kappa was 0.704 to 0.948. For hematology specimens, overall agreement was found on 69 of 80 observations; observed agreement on eight types of nucleated blood cells ranged from 0.5 to 1.0, and kappa was 0.429 to 1.0. Poorer color definition and image quality prevented accurate identification of lymphoblasts and eosinophils in particular. For histologic specimens, overall agreement was obtained on 56 of 66 observations, observed agreement on four categories of histologic change ranged from 0.73 to 0.93, and kappa was 0.47 to 0.9.

CONCLUSIONS

The desktop interactive video conferencing system, as configured in this study, was unsuitable for making definitive diagnoses from transmitted microscopic images.

Current issues in telepathology

Telepathology involves rendering diagnostic opinions on specimens at remote locations using computer and telecommunications technologies. Consultations are a routine practice pattern in pathology, as there is a large amount of diagnostic and prognostic information available from the examination of biopsy material that requires an extensive knowledge of diseases and their clinical implications. Pathologists therefore frequently request opinions from those who subspecialize in various diseases. The use of video technology to examine and consult on microscopical slides has been validated, although sparsely and with a number of technical issues as yet unresolved. There are two principal paradigms for telepathology: remote dynamic screening by robotic video microscopy and remote diagnosis from selected still video microscopical images. The former is more appealing to most pathologists; however, it requires very high speed telecommunications links that are expensive and may not be available in a given location. The latter method entails a significant reduction in the data on which the diagnosis is rendered, as one is dependent on the fields selected at the remote location. In addition, there are hybrid systems that combine limited robotic capabilities with high-resolution still images. Image compression can increase the number of images that can be transmitted over an otherwise-limiting telecommunications infrastructure. JPEG is the current standard for such compression. Despite certain limitations, telepathology has been demonstrated successfully at several sites around the world. As this technology matures, systems will offer higher resolution, standardization of file formats, and better compression at lower cost.

Utilization and cost savings of a wide-area computer network for neurosurgical consultation

BACKGROUND AND OBJECTIVE

Telemedicine systems offer many potential advantages for health care delivery. Most reports have centered on the delivery of primary and medical subspecialty care rather than on its impact on patient care and the potential for cost savings. In 1993, we implemented NeuroLink, a wide-area teleradiology network for delivery of specialty care in neurologic surgery at Allegheny General Hospital (AGH). This study was designed to determine the potential cost savings of such a network.

METHODS

We prospectively reviewed 100 consecutive telemedicine neurosurgical consultations from 20 western Pennsylvania community hospitals participating in the NeuroLink network. Data related to referring hospital, diagnosis, disposition of the patient, and mode of transportation were reviewed. To determine the potential cost savings, the differential of hospital-based charges between AGH and western Pennsylvania primary hospitals was calculated based on an average length of stay (LOS), patient bed costs, and transportation charges.

RESULTS

Of the 100 patients, 33 did not require transfer to a tertiary facility but were instead managed at the community hospital as a direct result of the remote diagnosis and image review disclosing that neurosurgical procedures or intensive care were not required. Cost analysis, comparing the average LOS at AGH with that of the average community hospital, including transportation, showed savings of $502,638.

CONCLUSION

Our neurosurgical wide-area computer network has led to more appropriate transfer of patients to a tertiary facility and significant estimated cost savings.

Remote connection to the Kyushu University Medical Center LAN using digital and analog telephone lines

SOHO (Small Office/Home Office) has recently become popular, as it makes working at home possible. Computers or Local Area Networks(LAN) connected to the office network from home are necessary for the implementation of this concept. Kyushu University has begun a service connecting home computers to the campus LAN for researchers, staff and students of the Faculty of Medicine. We have two different telephone connection methods. One connects the campus LAN and the home computer LAN using routers through the Integrated Services Digital Network (ISDN). The other connects computers at home to the workstation in the university, using modems and the PPP (Point to Point Protocol) through a public telephone analog line. This paper outlines our university SOHO connection system and discusses the merits and demerits of using telephone line connections.

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.

Color images in telepathology: how many colors do we need?

It is generally assumed that for telepathology, accurate depiction of microscopic images requires the use of "true color" (ie, 24 bits, eight bits each for red, green, and blue) in the digitized image used for transmission. If such a 24-bit color image file, which provides a palette of 16.7 million colors, could be reduced in size by decreasing the possible numbers of colors displayed in the image to 8 bits (palette of 256 colors), the image files would require less storage space, could be transmitted more rapidly, and would require less telecommunications bandwidth. However, such color reduction must not result in detectable image degradation, especially if the images are to be used for diagnosis. Therefore, we performed a carefully controlled study to determine whether pathologists could detect differences in the quality of microscopic images that were reduced from 24 to 8 bits of color. Thirty pathologists were each asked to view a set of 30 image pairs displayed on a computer monitor. Each image pair consisted of the original 24-bit color version and an 8-bit color-reduced version, derived using an adaptive color reduction algorithm with diffusion dithering. Observers were asked whether they could detect any difference in quality between the image pairs. Then, regardless of their answer, they were asked to choose the better quality image of the pair. Overall, there was not a statistically significant ability to consciously detect differences between the image pairs (P < .750). However, when forced to choose, there was a significant preference for the 8-bit images as being of "better quality" (P < .005). We conclude that telepathology applications may be able to take advantage of adaptive color reduction algorithms to reduce image file size without sacrificing image quality. Additional studies must be performed to determine the minimal image requirements for accurate diagnosis by telepatholgy.

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.

Telepathology diagnosis of prostrate needle biopsies

We conducted a prospective analysis of the diagnostic accuracy of a static-image telepathology system (Roche RIAS, Elon College, NC) in the interpretation of needle biopsies of the prostate (NBx). Two hundred consecutive cases received in consultation were included. Each case was examined by one of the researchers (MHW), and images were captured either according to the areas of concern designated by the referring pathologist (set A; 100 cases) or according to the judgment of MHW (set B; 100 cases). The other researcher (JIE) daily rendered diagnoses first on the video images and then by direct microscopy. Accuracy of video diagnosis was categorized as 0 (correct), 1 (minor error), 2 (major error), or 3 (deferred). An average of 5.49 images were captured per case in set A, and 5.28 for set B. Seventy-seven, 9, 9, and 5 cases were categorized as 0, 1, 2, and 3, respectively, for set A, and 78, 17, 1, and 4 cases, respectively, for set B. Video versus direct diagnoses for the type 2 errors were five carcinoma versus markedly atypical, two carcinoma versus atypical, one carcinoma versus nonspecific granulomatous prostatitis, and two benign versus atypical. In these difficult NBx, telepathology allowed an essentially correct diagnosis in almost all of the cases. The number of images required was reasonable, and the images were of excellent quality. However, the accuracy varied from set A to set B, with the fractions of nondeferred cases that were given an essentially correct video diagnosis totaling 91% and 99%, respectively (P < .01). Accuracy of telepathology diagnosis using static images may depend on the person capturing the images, even in the case of small biopsies.

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.

Improvement of monitoring of melanocytic skin lesions with the use of a computerized acquisition and surveillance unit with a skin surface microscopic television camera

BACKGROUND

Photographic documentation of melanocytic skin lesions is important. Storage and retrieval of slides, however, take much time and space.

OBJECTIVE

Our purpose was to develop and clinically test a computerized acquisition and surveillance (CAS) unit with a television camera for monitoring including measurements of lesional areas.

METHODS

A CAS unit connected with a skin surface microscopic television camera was used for monitoring of melanocytic nevi (MN). The lesional area and the skin surface microscopic appearance (SMA) were analyzed after 10 to 21 months in 54 of 1355 MN.

RESULTS

In 19 MN (35.2%), changes were found. In eight cases, changes in size of more or less than 15% were detected; in five cases only the SMA changed. In six cases both characteristics changed.

CONCLUSION

In approximately 25% of MN, changes were only detectable in the SMA but not with area measurements. This favors the use of systems such as CAS because only they allow a time-saving comparison of actual and previous 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.

Telepathology: a tool to aid in diagnosis and quality assurance in cervicovaginal cytology

The purpose of this study is to evaluate the use of a Teletransmission System with regard to quality of diagnosis and screening so as to establish its potential role in gynaecological cytology. Three aspects of its use in cytopathology have been considered: diagnosis, training, and quality control. The circumstances in which the system may be used for diagnosis, together with its advantages and disadvantages, are examined and discussed. In general, the cost/benefit in diagnostic use related to the experience of both the expert and the peripheral pathologist. The system may also contribute to training and quality assessment, particularly if combined with other automated services, such as image data bank.

Telepathology: frozen section diagnosis at a distance

Telepathology may be used to provide a frozen section service to hospitals without a department or institute of pathology. We have developed a telepathology system using the commercially available Integrated Services Digital Network (ISDN). The main software and hardware elements of our system are: Apple Macintosh workstations, a program for simultaneous transfer of image, voice and data, and a data bank for storage of patients' data and microscopic images. A picture instrument manager (PIM) makes remote control of microscopes or other instruments possible. The system connects the Department of Pathology of the University of Basel with the Regional Hospital of Samedan, 250 km away, and the Regional Hospital of Burgdorf, 100 km away. During a period of 20 months, frozen sections with the hospitals in Samedan and Burgdorf were performed in 53 patients. Between 54 and 58 s were required for the transfer of a diagnostic 8-bit grey level image containing 341 +/- 26.1 (standard error) kbytes (n = 13) or a diagnostic 24-bit colour image containing 165 +/- 16.9 kbytes (n = 40). Frozen section diagnosis was completed in 20-40 min. True-positive diagnoses of malignant tumours were achieved in 85.7% of cases (sensitivity = 0.857). No false-positive diagnosis was made. In 3 of the 53 cases telepathological diagnosis was not possible for technical reasons.

Current status of telepathology

Telepathology is moving from the experimental stage to become a regular feature of pathology practice. This has been made possible by technical advances in telecommunications and image processing. Since 1990 the University Hospital of Tromsø has provided local hospitals in northern Norway with a remote frozen section service and with access to video conferences for the review of microscopic findings and for the discussion of major diagnostic issues. Several other hospitals in Norway are now participating in this development and practical relations among pathology laboratories for the purpose of consultation and education will be the next step in the procedure. Similar developments in telepathology have taken place in other countries. Standardization of network and telepathology workstations will be needed before extensive international collaboration can be achieved. Progress in high quality video devices, high capacity telecommunication lines and improved image compression techniques will increase the usage of telepathology services and make them cost-effective. Thus, telepathology will contribute to the development of pathology services in the next century.