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 64kbit/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 13min, ranging between 2 and 42min. 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 misdiag-nosis 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 phyilodes 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 Intraoperatlve 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 sections, 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.     

Image sampling in static telepathology for frozen section diagnosis

BACKGROUND: A frozen section diagnostic service is often not directly available in small rural or mountain hospitals. In these cases, it could be possible to provide frozen section diagnosis through telepathology systems. Telepathology is based on two main methods: static and dynamic. The former is less expensive, but involves the crucial problem of image sampling. AIMS: To characterise the differences in image sampling for static telepathology when undertaken by pathologists with different experience. METHODS: As a test field, a previously studied telepathology method based on multimedia email was adopted. Using this method, three pathologists with different levels of experience sampled images from 155 routine frozen sections and sent them to a distant pathology institute, where diagnoses were made on digital images. After the telepathology diagnoses, the glass slides of both the frozen sections and the definitive sections were sent to the remote pathologists for review. RESULTS: Four of 155 transmissions were considered inadequate by the remote pathologist. In the remaining 151 cases, the telepathology diagnosis agreed with the gold standard in 146 (96.7%). There was no significant divergence between the three pathologists in their sampling of the images. Each case comprised five images on average, acquired in four minutes. The overall time for transmission was about 19 minutes. CONCLUSIONS: The results suggest that in routine frozen section diagnosis an inexperienced pathologist can sample images sufficiently well to permit remote diagnosis. However, as expected, the internet is too unreliable for such a time dependent task. An improvement in the system would involve integrated real time features, so that there could be interaction between the two pathologists.     

A prospective trial of telepathology for intraoperative consultation (frozen sections)

Telepathology is a maturing technology that, for a variety of reasons, has not been widely deployed. In addition, clinical validation is relatively modest compared with accepted telemedicine applications such as teleradiology. A prototype telepathology system (Tele-Path(sm)) featuring high-resolution images selected from a remote microscope site has been developed at the University of Alabama at Birmingham (UAB). To validate the diagnostic efficacy of the system, a prospective study was undertaken of parallel diagnoses by conventional microscopy and telepathology with a remotely operated microscope. Slides from 99 intraoperative consultations from 29 tissue/ organ sites in the University of Alabama Hospitals by 9 academic pathologists were used in the study. Each microscopic and telepathology diagnosis was compared with the final diagnosis rendered by a referee pathologist. Diagnoses were classified as correct, false positive, or false negative or classification error. Of the 99 frozen sections evaluated, 3 cases were deferred. Of the remaining 96 cases, 2 received incorrect diagnoses in both the microscopic and telepathology arms of the study. Three errors occurred only in the telepathology arm. There was 1 false-positive diagnosis, 1 false-negative diagnosis, and 1 classification error. Statistical analysis indicated no significant difference between telepathology and conventional microscopy. Qualitative data indicated that the pathologists were generally satisfied with the performance of the system. Telepathology using this system paradigm is sufficiently accurate for real time utilization in a complex surgical environment. Telepathology therefore may be an effective model to support the surgical services of hospitals lacking full-time pathology coverage, resulting in full-time access to anatomic pathology services.     

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.     

Frozen-section diagnosis by wireless telepathology and ultra portable computer: use in pathology resident/faculty consultation

Residents in anatomic pathology are allowed increased diagnostic responsibility including the initial interpretation of intraoperative frozen-section consultations during their years of training. This frozen-section responsibility requires staff faculty backup for diagnostic confirmation and consultation. In this study, we tested a telepathology system using an ultra portable computer with a 4.5-in diagonal screen (scrolled image size of 2.5 x 1.75 in, width x height) and both wireless Local Area Network (LAN) final connection from a DSL and wireless Wide Area Network (WAN) telecommunications. The diagnostic agreement for a chief resident/faculty staff duo using telepathology for 100 consecutive frozen-section cases (50 with wireless LAN final connection and 50 with wireless WAN) with limited clinical information was compared with the original frozen-section diagnosis rendered by other staff pathologists. There was diagnostic agreement for 95 of the 100 cases. For the 5 that were discordant, 2 were deemed to be errors in the original frozen-section diagnosis; 1 was not clinically important; and 2 were believed to have potential clinical implications. For the 2 having potential clinical importance, the absence of knowledge of the gross findings in each case and the preoperative biopsy results for one specimen contributed to the misinterpretation of the frozen sections. The median time between transmission of image(s) from the chief resident to the faculty consultant until diagnosis by the latter was 1 minute 42 seconds for wireless WAN and 51 seconds for the wireless LAN final connection to the display device. We conclude that a telepathology system using an ultra portable computer and wireless telecommunications is useful for frozen-section consultation between an experienced resident and a faculty member in pathology.     

Use of robotic telepathology for frozen-section diagnosis: a retrospective trial of a telepathology system for intraoperative consultation.

Telepathology is the practice of digitizing histological or macroscopic images for transmission along telecommunication pathways for diagnosis, consultation, or continuing medical education. Previous studies have addressed static versus dynamic imaging in several specimen types with a wide variety of systems and communication pathways. The goal of this paper was to assess the validity of a Web-based telepathology system for frozen section consultation within the Army Medical Department. The system provides real-time, dynamic remote control of a robotic microscope over standard Internet connections. Oftentimes, a solo pathologist is called on to provide diagnostic services without the support of immediate second or expert consultation during an intraoperative consultation. The use of telepathology is attractive because it provides an opportunity for pathologists to obtain immediate consultation. For purposes of the study, 120 consecutive frozen section cases were diagnosed at a distance using the system. Intraobserver agreement between the telepathology diagnosis and glass slide diagnosis was observed. Diagnostic agreement was 100% for a wide variety of specimens. This study suggests that such a system will help support pathologists located at distant sites.     

Frozen section telepathology by whole-slide imaging

Frozen sections represent an ideal niche application for telepathology. This review covers the key aspects of using telepathology for this purpose. While several options exist for remote reviewing of frozen section slides such as sending selected static images by e-mail, real-time video microscopy and statistic/dynamic robotic microscopy, the use of whole-slide imaging technology will be emphasized in this review. The performance characteristics of whole-slide imaging systems in various frozen section practice settings, based on validation studies or actual patient care, will be discussed as well as issues to consider when implementing whole-slide imaging telepathology to cover frozen sections.     

The validity of telepathological frozen section diagnosis with ISDN-mediated remote microscopy

We investigated 109 randomly selected frozen section specimens from lung surgery patients in a retrospective blind mode using telepathology equipment. The telepathology system applied (HISTKOM) used one ISDN B-channel and telemicroscopy with a remotely operated robotic microscope. The performance of telepathological frozen section diagnosis was compared with that of conventional frozen section diagnosis. The false-positive rate achieved was identical for both methods. The sensitivity (P=0.03), but not the specificity, was significantly lower for the telepathological method. The time needed to establish a diagnosis with the remote microscope was too high; therefore, upgrading to multichannel technology is recommended. The quality of the images transmitted was judged to be sufficient by the pathologists involved in the study. In conclusion, with further technical improvements in telemicroscopy and additional experience in telepathology, remote diagnosis seems to be feasible. Received: 4 May 1999 / Accepted: 11 January 2000     

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.     

Robotic telepathology for intraoperative remote diagnosis using a still-imaging-based system.

The aim of the present study was to assess whether a telemicroscopy system based on static imaging could provide a remote intraoperative frozen section service. Three pathologists evaluated 70 consecutive frozen section cases (for a total of 210 diagnoses) using a static telemicroscopy system (STeMiSy) and light microscopy (LM). STeMiSy uses a robotic microscope, enabling full remote control by consultant pathologists in a near real-time manner. Clinically important concordance between STeMiSy and LM was 98.6% (95.2% overall concordance), indicating very good agreement. The rates of deferred diagnoses given by STeMiSy and LM were comparable (11.0% and 9.5%, respectively). Compared with the consensus diagnosis, the diagnostic accuracy of STeMiSy and LM was 95.2% and 96.2%. The mean viewing time per slide was 3.6 minutes, and the overall time to make a diagnosis by STeMiSy was 6.2 minutes, conforming to intraoperative practice requirements. Our study demonstrates that a static imaging active telepathology system is comparable to dynamic telepathology systems and can provide a routine frozen section service.     

Low-cost telepathology system for intraoperative frozen-section consultation: our experience and review of the literature

We have established a low-cost noncommercial system of dynamic real-time telepathology for light microscopic diagnosis that was used to aid intradepartmental consultation for frozen-section diagnosis. Fifty cases were performed. For each case, multiple diagnoses were made and compared, namely, those made by the pathologist on duty (D1), by a subspecialist or senior using telepathology (D2), by the same pathologist using a light microscope (D3), and the final diagnosis (D4). A comparison of D1 and D2 revealed that 37 cases (74%) were diagnosed more precisely by D2. In 9 (18%) of 50 cases, there was a positive major impact on the operation as a result of teleconsultation. The results of D2 and D3 showed good agreement (kappa = 0.97). The average time span required for telepathology is short compared with routine intradepartmental consultation. Our experience showed that telepathology is a good tool for frozen-section consultation and imposes little additional cost.     

Offline telepathology diagnosis of colorectal polyps: a study of interobserver agreement and comparison with glass slide diagnoses

BACKGROUND/AIMS: Technological advances have produced telepathology systems with high quality colour images and reasonable transmission times. Most applications of telepathology have centred on the remote diagnosis of frozen sections or remote real time expert opinions. This study investigates the reproducibility and accuracy of offline telepathology as a primary diagnostic medium for routine histopathology specimens. METHODS: One hundred colorectal polyps (50 hyperplastic, 50 adenomatous) were presented in a randomised order to five histopathologists as offline images on a telepathology workstation. Six images of each case were used: the slide label, a low power scan of all material on the slide, and four higher magnification views. The times taken to prepare the images, and to make the diagnoses, were recorded. Interobserver agreement was measured with kappa statistics and compared with the glass slide diagnoses. RESULTS: The kappa statistics for the interobserver agreement on the telepathology images lay in the range of 0.90-1.00, which is interpreted as excellent agreement, and were significantly higher than those for the glass slide diagnoses (range, 0.84-0.98; p = 0.001). The median time taken to capture the images for a case was 210 seconds. The median time taken to make a diagnosis from the telepathology images was five seconds, which was significantly shorter than for the glass slide diagnoses (median, 13 seconds; p < 0.0005). CONCLUSIONS: Offline telepathology has the potential to be a primary diagnostic medium for routine histopathology with a high degree of reproducibility and short diagnosis times. Further studies are required to validate offline telepathology for different types of specimens and different operators of the image capture system.     

Robotic telepathology: efficacy and usability in pulmonary pathology

Robotic telepathology is well established in the USA as a method of case referral, but is less frequently used in the UK. Using cases covering a broad spectrum of pulmonary pathology, this study assessed its application in primary diagnosis and its functionality in terms of accuracy of diagnosis and time per case, for both small biopsies and open lung biopsies/resections. Forty cases (20 bronchoscopic and 20 surgical lung biopsy/resection specimens) were reviewed in blinded fashion by a single pathologist using robotic telepathology. Connection between the John Radcliffe and Royal Brompton Hospitals was via 10 Mb/s LAN to the Internet (supported by the Joint Academic Network). The cases were then randomized and reviewed a second time with conventional light microscopy. Diagnosis, initial time to reach diagnosis, and overall time per case were recorded. In two bronchoscopic biopsy cases, there were clinically significant differences between telepathology and conventional light microscopy, one probably attributable to user inexperience and the other to either speed of image capture or digital image quality. In the surgical lung biopsies and resections, there was one variation of opinion: with telepathology a case was considered to be probably mesothelioma, whereas this was thought less likely on light microscopy. In both instances, immunohistochemistry was requested prior to clinical management. Telepathology was 14 times slower than conventional light microscopy when examining bronchoscopic biopsies. The average time spent per slide was 7 min 21 s, compared with 32 s per slide with conventional light microscopy. When assessing open lung biopsies and resections, telepathology was five times slower, at 6 min 13 s compared with 1 min 10 s with conventional light microscopy. This study showed that robotic telepathology is accurate for primary diagnosis in pulmonary histopathology, but modifications in both laboratory protocols and telepathology hardware are needed to decrease the time difference between telepathology and conventional light microscopy, for telepathology to be usable within the framework of a busy referral practice.     

Clinical evaluation of an international static image–based telepathology service

Telepathology is the use of telecommunications technology as a means to facilitate transfer of image-rich pathology data between remote locations for the purposes of diagnosis, education, and research. Although varying levels of technology exist to accomplish this task, static image--based systems are currently the most widely used around the world. Field selection and image quality have often been identified as major impediments to the successful use of static images for diagnostic telepathology. Between November 1994 and July 1999, the Armed Forces Institute of Pathology (AFIP) performed electronic consultation on over 1,250 static image--based cases, recording a clinically significant concordance rate of 97.3% between telepathology and final diagnosis (in cases in which follow-up material was available). For the same subset of cases, an absolute concordance rate of 73.7% was attained. A review of the case flow and construction of the AFIP telepathology system is presented, as well as factors that have an impact on the diagnostic accuracy of static image-based telepathology sytems in general.     

Analysis of deferrals on static telepathology consultation service

The objective of this study is to analyze the deferrals in static telepathology consultation service. A store and forward approach is used to transmit cases from two remotely located rural centers to Tata Memorial Hospital. A total of 346 tele-surgical pathology cases were accessioned for second opinion and were reported from January 2002 to August 2005. The glass slides and paraffin blocks were reviewed at a later date and the telepathology diagnosis was compared with the final diagnosis rendered on light microscopy. Of all 251 teleconsults referred from one of the referring centers, a telepathology diagnosis was rendered in 205 cases and 46 cases were deferred. The reasons for deferral were as follows: the requirement for ancillary studies (40 cases), clinical details (5 cases) and poor quality sections and images (1 case). In all these deferred cases, a probable diagnosis was rendered by the telepathologist and was compared with the final diagnosis after paraffin block evaluation. In 47% of the cases, the "probable" diagnosis on telepathology matched the final diagnosis.     

A feasibility study of virtual slides in surgical pathology in China

China's huge territorial expanse and its imbalance of regional economic development have resulted in an uneven distribution of experienced pathologists. Developing telepathology for consultation is of special relevance to China. We developed a newly designed telepathology workstation, which includes a small file size of each slide, permitting easy transmission, storage, and manipulation, and a feedback function, and also evaluated its feasibility in surgical pathology in China. Four hundred cases covering a broad spectrum of surgical pathology problems were investigated in a blinded fashion by the 2 pathologists using this virtual microscope system. These cases were then randomized and re-reviewed a second time with light microscope. Diagnoses and time spent for each diagnosis were recorded for both methods. The diagnostic accuracies achieved by viewing glass slides and virtual images were 97.25% (389 of 400) and 95.5% (382 of 400) for pathologist A and 96.25% (385 of 400) and 94.75% (379 of 400) for pathologist B, respectively. There was no significant diagnostic discrepancy between the 2 methods for the 2 pathologists. The average times for viewing a virtual slide were 3.41 and 5.24 minutes for pathologists A and B, respectively, whereas the average times for viewing a glass slide were 1.16 and 3.35 minutes for pathologists A and B. There was a statistical difference between the time costs of the 2 methods. However, the slight time increase using virtual slides is less than that using dynamic telepathology and traditional consultation, and is acceptable to the pathologists. These results showed that this newly designed virtual microscope system have an acceptable diagnostic accuracy that is of practical value and may be suitable for application in China.     

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.     

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.     

Development and experience with an integrated system for transplantation telepathology

Rapid and accurate interpretation of allograft biopsies influences the outcome after organ transplantation. Expert histopathologic interpretation can also determine whether a donor organ should be used for transplantation or disposed. These and similar considerations in the field of Transplantation Pathology prompted us to develop a static image, store-and-forward telepathology system capable of rendering accurate, robust, and confidential communication by using readily available equipment and bandwidth capabilities for interactive real-time second opinion consultation. Between July 1999 and October 2000, 102 cases were transmitted, including 78 for second opinion and 1 for primary diagnosis with 6 (5 real-time) frozen sections. Full agreement with the original diagnosis was obtained in 67 of 78 (86%) cases; in 11 (14%) cases, teleconsultation resulted in 8 minor and 3 clinically significant differences of opinion. This led to a change in therapy in 1 case and further evaluation in 2 other cases. We conclude that static image, store-and-forward telepathology can enhance the practice of transplantation pathology, but a multidisciplinary team for ongiong support and development is required. This technology has the potential to promote case sharing, conduct continuing education, build consensus, and standardize readings of biopsies in multicenter trials in which histopathologic findings represent important outcome measures.     

Assessment of diagnostic accuracy and feasibility of dynamic telepathology in China

To assess the feasibility, including diagnostic accuracy and time cost, of a real-time telepathology system with pathologic slides, 600 cases covering a wide spectrum of lesions from 16 organ systems were tested. The "correct" diagnosis (gold standard) was established as a consensus by 2 experienced pathologists. The cases were first examined by 4 pathologists at different levels of experience with dynamic telepathology. Cases were then reviewed by the same pathologists using light microscopy in a blinded fashion 3 weeks to 2 months later. A diagnosis, together with reading times for telepathology and light microscopy, was recorded for each case. Diagnostic accuracy by telepathology was 94.8% (569/600), 93.3% (560/600), 91.6% (550/600), and 97% (388/400) for pathologists A, B, C, and D, respectively. Telepathologic diagnosis was concordant with the gold standard and with direct microscopy, with a mean of 94.2% and 99.26%, respectively. Most cases (510 or 85%) were diagnosed in 15 to 40 minutes by telepathology, with a mean of 17.0 minutes. The time needed to review a slide by telepathology was 3 to 4 times longer than that of standard light microscopy. All 4 pathologists were able to render a diagnosis in all cases. Our results showed that robotic telepathology is sufficiently accurate for primary diagnosis in surgical pathology, but modifications in laboratory protocols, telepathology hardware, and internet speed are needed to reduce the time necessary for diagnosis by telepathology before this method may be deemed suitable for use in a busy practice.