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

Validation and implementation of Aperio LV1 remote live view telepathology system for intraoperative frozen section diagnosis

Introduction

Telepathology (TP) allows for remote slide review with performance comparable to traditional light microscopy. Use of TP in the intraoperative setting allows for faster turnaround and greater user convenience by obviating the physical presence of the attending pathologist. We sought to perform a practical validation of an intraoperative TP system using the Leica Aperio LV1 scanner in tandem with Zoom teleconferencing software.

Methods

A validation was performed in accordance with recommendations from CAP/ASCP, using a retrospectively identified sample of surgical pathology cases with a 1 year washout period. Only cases with frozen-final concordance were included. Validators underwent training in the operation of the instrument and conferencing interface, then reviewed the blinded slide set annotated with clinical information. Validator diagnoses were compared to original diagnoses for concordance.

Results

60 slides were chosen for inclusion. 8 validators completed the slide review, each requiring 2 h. The validation was completed in 2 weeks. Overall concordance was 96.4%. Intraobserver concordance was 97.3%. No major technical hurdles were encountered.

Conclusion

Validation of the intraoperative TP system was completed rapidly and with high concordance, comparable to traditional light microscopy. Institutional teleconferencing implementation driven by the COVID pandemic facilitated ease of adoption.

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.

Validation of Remote Digital Frozen Sections for Cancer and Transplant Intraoperative Services

Introduction

Whole-slide imaging (WSI) technology can be used for primary diagnosis and consultation, including intraoperative (IO) frozen section (FS). We aimed to implement and validate a digital system for the FS evaluation of cancer and transplant specimens following recommendations of the College of American Pathologists.

Materials and Methods

FS cases were routinely scanned at ×20 employing the "Navigo" scanner system. IO diagnoses using glass versus digital slides after a 3-week washout period were recorded. Intraobserver concordance was evaluated using accuracy rate and kappa statistics. Feasibility of WSI diagnoses was assessed by the way of sensitivity, specificity, as well as positive and negative predictive values. Participants also completed a survey denoting scan time, time spent viewing cases, preference for glass versus WSI, image quality, interface experience, and any problems encountered.

Results

Of the 125 cases submitted, 121 (436 slides) were successfully scanned including 93 oncological and 28 donor-organ FS biopsies. Four cases were excluded because of failed digitalization due to scanning problems or sample preparation artifacts. Full agreement between glass and digital-slide diagnosis was obtained in 90 of 93 (97%, κ = 0.96) oncology and in 24 of 28 (86%, κ = 0.91) transplant cases. There were two major and one minor discrepancy for cancer cases (sensitivity 100%, specificity 96%) and two major and two minor disagreements for transplant cases (sensitivity 96%, specificity 75%). Average scan and viewing/reporting time were 12 and 3 min for cancer cases, compared to 18 and 5 min for transplant cases. A high diagnostic comfort level among pathologists emerged from the survey.

Conclusions

These data demonstrate that the "Navigo" digital WSI system can reliably support an IO FS service involving complicated cancer and transplant cases.

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.

Intérêt de la télépathologie dans le diagnostic rapide des spécimens neurochirurgicaux

To determine whether still digital images of neurosurgical specimens sent by e-mail are an effective and safe way of obtaining an emergency pathological diagnosis, representative images from 48 neurosurgical smear specimens were digitized, compressed and sent by electronic mail to our consultant neuropathologist with relevant clinical and radiological information. The time to select, digitize, compress and send the images for each case was recorded. Comparison was made between diagnosis made from digital images (DI) and historical smear (HS) using the original permanent section (PS) diagnosis as the gold standard. A diagnosis of normal vs. abnormal, neoplastic vs. non-neoplastic, primary vs. secondary and tumor grade was made in each case. The mean time for selection and digitalization of each case was 9.51 minutes. The number of correct pathological diagnosis was 41/48 using DI and 48/48 using HS, giving an accuracy rate of 85.4% and 100% respectively. DI was 100% sensitive in recognizing neoplastic tissue but only 98% specific. Most inaccuracies were in grading and caused by problems with field selection and familiarity with the technique. We conclude that static digital images are reliable and safe method of interpreting tissue during neurosurgical procedures. This corresponds with the findings of previous studies.

Image quality issues in a static image-based telepathology consultation practice

Field selection and image quality have often been identified as impediments in the successful employment of static-image telepathology. One thousand seven hundred fifty-three electronic consultations using static images were performed at the Department of Telemedicine, Armed Forces Institute of Pathology (AFIP) between November 1994 and September 2001, with 98.3% receiving a telepathology diagnosis. In 47.9% of cases, imagery was considered good by AFIP consultants, 38.5% were considered adequate, and 14.6% of cases were considered to have poor-quality imagery. Deficiencies in image quality were recorded for each case. Cases with imagery rated as good averaged significantly fewer deficiencies per case (0.45, range: 0 to 3) than cases with imagery rated adequate (0.95, range: 0 to 6) or poor (2.4, range: 0 to 7). Deficiencies in focus were most commonly identified in this series of cases (28.1%), followed by improper white balancing of the capture device (14.1%) and inadequate resolution (10%). Cases in which images were of inadequate resolution showed an increased likelihood for discordance between the telepathology diagnosis and the diagnosis rendered on follow-up material ("truth diagnosis"). Inadequate field selection, although only cited in 6.7% of cases overall, was seen with a significantly higher frequency in cases in which there was discordance between the telepathology and truth diagnosis. A review of common image deficiencies in static-image telepathology and possible causes is presented.

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 for the biopsy specimens from human allografted kidney: effectiveness and pitfalls

This study was conducted to examine the validity and accuracy of telepathology for biopsy specimens from allografted kidney. The still video images of paraffin sections were transmitted via a two-way telephone by use of a digitized telephone network, ISDN. The quality of the transmitted images was sufficient for the diagnosis, especially at higher magnification. A total of 37 needle biopsy specimens from the 31 allografted kidneys were presented for consultation and diagnosed by an expert pathologist at Tottori University, until July 2000. The average number of transmitted images was 7.1 (range 3-12). Of the 37 specimens, diagnoses by telepathology agreed well with those made through direct microscopy in the 30 specimens. Insufficient or improper diagnosis was made in four specimens, in which proper and pathognomonic still images were not transmitted. Three cases were not diagnosed by telepathology because of the difficulty in making differential diagnosis. From these results, we concluded that telepathology is useful for transplantation pathology, in spite of limitations in some cases.

Telepathology for routine light microscopic and frozen section diagnosis

Telepathology (TP) uses telecommunication linkages to electronically capture, store, retrieve, and transmit images to distant sites. We assessed the feasibility of a dynamic real-time TP system for light microscopic (LM) diagnosis of anatomic pathology specimens, including frozen sections. Six pathologists, in 2 separate periods, read a set of 160 retrospectively retrieved slides (80 of which were frozen sections) by TP and LM. Reading times were recorded. Diagnoses were compared with the reference diagnosis (established by a group of 5 independent pathologists) and graded on a scale of 0 to 2 (2, correct; 1, incorrect but no clinical impact; 0, incorrect with clinical impact). Overall, LM was more accurate than TP compared with the reference diagnosis (score, 1.68 vs 1.54). There was no difference in accuracy between frozen section and paraffin-embedded tissue. Intraobserver agreement ranged from 82.5% to 88.2%. The average reading time was 6.0 minutes for TP and 1.4 minutes for LM. During the study, reading time decreased for TP but not for LM. These results show that despite marginally lower accuracy and longer reading times, TP isfeasible for routine light microscopic diagnosis, including frozen sections.

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.

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.

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: a diagnostic tool for the millennium?

Many developments in science have their origins in science fiction and telepathology is no exception. The concept was first illustrated in 1924 in the magazine 'Radio News'. It was not until 1980, however, that the first working telepathology system was demonstrated. Although the system was shown to work, it required special hardware, dedicated software and special microwave transmission links to be installed. Little interest was shown worldwide because of the very high cost and the inability of many people to replicate such a system. Ten years later, the personal computer (PC) was able to provide more than adequate performance at low cost for both image display quality and speed, and the development of video technology had resulted in high quality images being produced by television cameras that were now easily affordable. Microscopes were also relatively cheaper. Thus, by 1993 or 1994, all the hardware necessary to produce a telepathology system was available at reasonable cost. Telepathology can now be used for remote primary diagnosis, remote referral to a specialist pathologist, remote teaching, remote presentation of post-mortem or microscopic findings, quality assurance image circulation and feedback, and consensus diagnosis for pathological review in clinical trials. There are two residual problems. The first concerns the speed of data transmission, commonly referred to as the bandwidth. The second is that the software provided by most of the manufacturers and suppliers of these systems is not entirely suitable to the task and the systems are not interoperable. It is clear that the approach of the manufacturers is at present unlikely to produce telepathology systems which pathologists feel comfortable in using. A somewhat different approach is illustrated by the accompanying article in this issue from the Berlin group, where a relatively simple Java-based applet and the Internet are used to allow single or multiple users to view slides on a robotic microscope. This could form the basis for a truly useful system, but still needs modification for some applications.

Telemedicine using a desktop conference system (Phoenix) in Kyushu, Japan

OBJECTIVE

The Kyushu area of southwestern Japan has several mountains and 157 inhabited islands. We assessed the feasibility of implementing a desktop conference (DTC) system to improve medical care in this area. TELECOMMUNICATIONS TECHNOLOGY AND EQUIPMENT: The Phoenix DTC system (NTT Corporation, Tokyo, Japan) for personal computers includes a microphone, speaker, color CCD camera, and appropriate software. We used a digital camera for still pictures and image-analysis software for radiographs and CT and MRI films. The system was installed on a Pentium 133 MHz computer, which was connected by ISDN line at a 128 kbps data rate to a clinic on a small island where one physician cares for 1000 residents, two small nursing offices where each nurse tends 100 residents, two nursing homes, a hospital in a mountainous area, and the residence of a patient with atopic dermatitis. Connections were made once a week for a period of 6 months.

RESULTS

The transmitted still pictures; e.g., senile nevus, atopic dermatitis, chickenpox, and a radiograph of a suspected fracture, were useful for diagnosis and clinical decision making. We received and responded to inquiries from residents of the participating nursing homes on nutrition, senile depression, nevus, decubitus ulcers, urinary tract infection, and protection against Legionella infection. We also used the system to deliver lectures on pediatrics to nurses; provided case discussions on diaphragmatic herniation and subtentorial tumor; and had on-line presentation of a patient with beta-thalassemia using presentation software.

CONCLUSION

The DTC system used in the present study seemed technically satisfactory and useful in improving medical care in remote sites of Japan.