Applications and Uses
Telecytology. Rapid real-time telecytology has been documented to be useful in rapid on-site evaluations (ROSE) of the adequacy of fine needle aspirations (FNA).17-21 Nevertheless, current Medicare reimbursement is limited given that ROSE is cost prohibitive, time consuming, and affects productivity in cytology laboratories.17,22,23 Estimates of the time to provide ROSE for 1 procedure without telecytology range from 48.7 to 56.2 minutes.17,23 The use of telecytology significantly reduces pathologist ROSE time without losing quality to about 12 minutes, of which only an average of 7.5 minutes was spent by the cytopathologist for the ROSE diagnosis.17-21 ROSE also can be used for distant and remote locations to improve patient care.17-21 Multiple vendors provide real-time telecytology service. Innovations using smartphone adapters, digital cameras that could work as their own IP addresses, and connection with high-speed dedicated connections with viewing platforms on high-sensitivity monitors can facilitate ROSE to improve patient management.24,25 The successful accurate use of ROSE has been described; however, there are currently no FDA-approved telepathology ROSE platforms.17-19,21-25
To date, the FDA has not approved any telecytology whole slide scanner due to a lack of z-stacking capability in submitted scanners.7,21 Not all whole slide scanners offer z-stacking, though even in those that do offer it, the time necessary to scan the entire slide with adequate z-stacking takes too long to be clinically acceptable for many situations involving ROSE.21 WSI has also been used to develop international consensus for cytologic samples.26 Published recommendations for the validation of these other modalities before usage follow the spirit of the CAP guidelines (as far as multiple cases with high concordance rates) for validation of WSI for diagnostic purposes but vary on the exact number of slides and acceptable concordance rate.21,27 For ROSE with a robotic microscope without any on-site cytology personnel, documented standardized training of nonpathology staff members, such as the radiologist or other physician performing the FNA procedure, may be needed to enable the performance of ROSE telecytology and ensure compliance with regulations.2,21 Besides ROSE, there are published validations for telecytology in primary diagnosis and QA, indicating a role for telecytology for diagnosis for laboratories that have properly validated and implemented the laboratory-developed test.28-30
Frozen section. Telepathology has significant potential to improve access to frozen section consultation.5,31-33 Benefits to improving access to frozen section include providing frozen section consultation at remote or off-site locations, increasing access to subspecialty consultation, improving workflow by eliminating the need to travel off-site to the frozen section case, cost savings in staff work time, and providing educational opportunities for pathology trainees.5,31-33 In our experience, WSI with real-time viewing of frozen section allows for the assessment of transplant tissues, which is an evaluation that generally occurs at night. Discrepancies from frozen section telepathology using WSI to the final diagnosis may occur and those specific to WSI could result from slide or image quality, internet connectivity, and lack of training in using the telepathology system.32 Other issues that may lead to discrepancies between the frozen section diagnosis and the final diagnosis may occur with the review of glass slides by light microscopy.34 Appropriate performance of validation, training, implementation, and quality control for telepathology can help in reaping the benefits while mitigating the risks.2 In a large study comparing frozen section evaluation by telepathology with light microscopy, the sensitivity and specificity of frozen section were comparable between telepathology and light microscopy with a trend toward greater sensitivity by telepathology (0.92 and 0.99 for telepathology vs 0.90 and 0.99 by light microscopy alone, sensitivity and specificity, respectively).33
Other applications. Evidence for efficacy in surgical pathology diagnosis led to FDA approval of the Philips IntelliSite Digital Pathology in 2017 and the Leica Aperio AT2 DX in 2020 WSI platforms.6-8 The use of WSI in surgical pathology has been successfully validated or used in clinical practice at several pathology laboratory settings with documented benefits in the literature for primary and secondary diagnoses, QA, research, and education.6-8,35-45 Benefits of telepathology include improved ergonomics and access to real-time pathologic services in remote areas or during on-site pathologist absence and expert second opinions. Telepathology also may reduce risk of slide loss during transport, shortened turnaround time, reduced costs of operation through workflow efficiencies, better load balancing, improve virtual collaboration, and digital storage of slides that may be irreplaceable.3-8,35-45 Telepathology also has been shown to be useful for education, improving access to learning materials and increasing quality instructional materials at a lower cost.45 The increased ease of collaboration with remote experts and access to slide material for other pathologists improves QA capabilities.3-8,35-45 The availability of virtual slides is expected to promote further research in telepathology and pathology due to the increased availability of virtual material to researchers.1,5,46
Telehematology. Published validations have shown effectiveness for hematopathology specimens, such as the peripheral smear. Telehematology also has demonstrated potential in a laboratory after proper validation and implementation as a laboratory-developed test.37,47-49
Telemicrobiology and Computer-Assisted Pathologic Diagnosis. Telemicrobiology also has been successfully used for clinical, educational, and QA purposes.50 The digitalization of slides involved with telepathology enables further innovation in machine learning for computer-assisted pathologic diagnosis (CAPD), which is already being used clinically for cervical Pap smears.20 An artificial intelligence (AI)–based algorithm analyzes the slides to identify cells of interest, which are presented to the cytopathologist for confirmation.20 However, the expansion of CAPD to include a variety of specimen types or diagnostic situations as well as safely and effectively take initiative in completing an accurate automated diagnosis requires additional development.20,51,52 One of the key factors for machine learning to develop AI is the provision of a corpus of data.51,52 Public, open-source data sources have been limited in size while private proprietary sources have highly restricted and expensive access; to address this, there is a current effort to build the world’s largest public open-source digital pathology corpus at Temple University Hospital, which may help enable innovations in the future.52