Ex Vivo Fluorescence Confocal Microscopy in Specimens of the Liver: A Proof-of-Concept Study

[Fluorescence confocal microscopy-complete digitization of pathology]

BACKGROUND

Fluorescence-based confocal microscopy (FCM) can be used to create virtual H&E sections in real time. So far, FCM has been used in dermato-, uro-, and gynecopathology. FCM allows the creation of a completely digitized frozen section, which could potentially replace conventional frozen sections in the future.

OBJECTIVE

The aim of the current work is to implement FCM technology as a component of fully digitized processes in the pathological workflow. For this purpose, the current use of FCM in liver transplant pathology will be extended to other disciplines such as urology and otorhinolaryngology.

MATERIALS AND METHODS

The FCM technique continues to be used prospectively on native tissue samples from potential donor livers. Conventional frozen sections are used comparatively to virtual FCM scans.

RESULTS

The data show a nearly perfect agreement for the detection of cholangitis, fibrosis, and malignancy, and a high level of agreement for, e.g., macrovesicular steatosis, inflammation, steatohepatitis, and necrosis between virtual FCM scans and conventional routine diagnostic frozen sections.

CONCLUSION

Since the availability of time- and cost-intensive frozen section diagnostics in the context of transplant pathology in continuous operation (24/7) is now only established at very few university centers in Germany due to an increasing shortage of specialists, the use of FCM could be an important building block in the current process leading towards a fully digitized pathology workflow and should thus be extended to various disciplines.

Fluorescence confocal microscopy on liver specimens for full digitization of transplant pathology

Fluorescence confocal microscopy (FCM) is a rapidly evolving tool that provides real-time virtual HE images of native tissue. Data about the potential of FCM as an alternative to frozen sections for the evaluation of donor liver specimens are lacking so far. The aim of the current study was to determine the value of FCM in liver specimens according to the criteria of the German Society for Organ Procurement. In this prospective study, conventional histology and FCM scans of 50 liver specimens (60% liver biopsies, 26% surgical specimens, and 14% donor samples) were evaluated according to the German Society for Organ Procurement. A comparison of FCM scans and conventional frozen sections revealed almost perfect levels of agreement for cholangitis (κ = 0.877), fibrosis (κ = 0.843), and malignancy (κ = 0.815). Substantial levels of agreement could be obtained for macrovesicular steatosis (κ = 0.775), inflammation (κ = 0.763), necrosis (κ = 0.643), and steatohepatitis (κ = 0.643). Levels of agreement were moderate for microvesicular steatosis (κ = 0.563). The strength of agreement between frozen sections and FCM was superior to the comparison of conventional HE and FCM imaging. We introduce FCM as a potential alternative to the frozen section that may represent a novel approach to liver transplant pathology where timely feedback is crucial and the deployment of human resources is becoming increasingly difficult.

Real-Time Evaluation of Thyroid Cytology Using New Digital Microscopy Allows for Sample Adequacy Assessment, Morphological Classification, and Supports Molecular Analysis

Thyroid cytological examination, a key tool in preoperative thyroid nodule evaluation, is specific and accurate; some drawbacks are due to inadequate or indeterminate cytological reports and there is a need for an innovative approach overcoming the limits of traditional cytological diagnostics. Fluorescence laser confocal microscopes (FCM) is a new optical technique for allowing immediate digital imaging of fresh unfixed tissues and real-time assessment of sample adequacy and diagnostic evaluation for small biopsies and cytological samples. Currently, there are no data about the use of FCMs in the field of thyroid nodular pathology. The aims of this study were to test FCM technology for evaluating the adequacy of FNA samples at the time of the procedure and to assess the level of concordance between FCM cytological evaluations, paired conventional cytology, and final surgical histology. The secondary aim was to define the integrity of nucleic acids after FCM evaluation through NGS molecular analysis. Sample adequacy was correctly stated. Comparing FCM evaluation with the final histology, all cases resulting in malignant or suspicious for malignancy at FCM, were confirmed to be carcinomas (PPV 100%). In conclusion, we describe a successful application of FCM in thyroid preoperative cytological evaluation, with advantages in immediate adequacy assessment and diagnostic information, while preserving cellular specimens for permanent morphology and molecular analysis, thus improving timely and accurate patient management.

Potential Use of Vivascope for Real-Time Histological Evaluation in Endoscopic Laryngeal Surgery

We aimed to assess the feasibility of using confocal laser scanning microscopy (CLSM) for the real-time ex vivo examination of histological samples of laryngeal lesions and to evaluate the correlation between CLSM and definitive histological results. This preliminary study included eight consecutive patients with "suspected" laryngeal lesions who were candidates for endoscopic laryngeal surgery. The obtained samples were evaluated using CLSM and classified as "inadequate" or "adequate" (high- and low-grade dysplasia, in situ and invasive carcinoma, positive surgical margin, and inflammatory outbreaks). CLSM showed the macro image in all cases and generated a digital version. All the samples were defined as adequate during CLSM and confirmed at histopathology: low-grade dysplasia (n = 5), low- and high-grade dysplasia (n = 2), and high-grade dysplasia (n = 1). Four samples had an involved resection margin, and three samples revealed the presence of inflammatory outbreaks. CLSM can be applied to larynx pathology with excellent agreement with final histological results.

Ex vivo confocal microscopy detects basic patterns of acute and chronic lesions using fresh kidney samples

BACKGROUND

Ex vivo confocal microscopy is a real-time technique that provides high-resolution images of fresh, non-fixed tissues, with an optical resolution comparable to conventional pathology. The objective of this study was to investigate the feasibility of using ex vivo confocal microscopy in fusion mode (FuCM) and the haematoxylin and eosin (H&E)-like digital staining that results for the analysis of basic patterns of lesion in nephropathology.

METHODS

Forty-eight renal samples were scanned in a fourth-generation ex vivo confocal microscopy device. Samples were subjected to confocal microscopy imaging and were then processed using conventional pathology techniques. Concordance between the techniques was evaluated by means of the percentage of agreement and the κ index.

RESULTS

Agreement between conventional microscopy and H&E-like digital staining was strong (κ = 0.88) in the evaluation of acute tubular damage and was substantial (κ = 0.79) in the evaluation of interstitial fibrosis, interstitial inflammation, arterial and arteriolar lesions. H&E-like digital staining also allows rapid identification of extracapillary proliferation (κ = 0.88), necrosis and segmental sclerosis (κ = .88) in the glomerular compartment, but the results reported here are limited because of the small number of cases with these glomerular findings.

CONCLUSIONS

FuCM proved to be as effective as conventional techniques in evaluating the presence of acute tubular necrosis and interstitial fibrosis changes, but in fresh tissue. The ease of acquisition of ex vivo confocal microscopy images suggests that FuCM may be useful for rapid evaluation of kidney biopsies and to restructure the clinical workflow in renal histopathology.

Role of VivaScope 2500 ex vivo confocal microscopy in skin pathology: Advantages, limitations, and future prospects

BACKGROUND

Vivascope 2500 ex vivo confocal microscopy (EVCM) is an emerging optical imaging device that allows nuclear level resolution of freshly excised tissues. EVCM provides, rapid real-time pathological examination in many subspecialties of pathology including skin, prostate, breast, liver, etc. In contrast to traditional time-consuming frozen sectioning and histological analysis.

AIMS

To evaluate the current state of EVCM utilization.

MATERIALS AND METHODS

This study highlights the advantages, limitations, and prospects of EVCM in skin pathology.

RESULTS

Our findings demonstrate that EVCM is a promising adjunctive tool to assess margins in Mohs surgery and to provide rapid, accurate diagnosis of cutaneous tumors, infectious and inflammatory diseases.

CONCLUSION

EVCM is a revolutionary device that can be used as an adjunct to paraffin-fixed, hematoxylin and eosin-stained slides and frozen sectioning. Additional refinements are required before EVCM can be used as an alternative to frozen sectioning or traditional tissue processing.

New digital confocal laser microscopy may boost real-time evaluation of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) from solid pancreatic lesions: Data from an international multicenter study

BACKGROUND

Pancreatic cancer is an aggressive malignancy and a leading cause of cancer death worldwide; its lethality is partly linked to the difficulty of early diagnosis. Modern devices for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) were recently developed to improve targeting and sampling of small lesions, but innovative technologies for microscopic assessment are still lacking. Ex vivo fluorescence confocal laser microscopy (FCM) is a new digital tool for real-time microscopic assessment of fresh unfixed biological specimens, avoiding conventional histological slide preparation and potentially being highly appealing for EUS-FNB specimens.

METHODS

This study evaluated the possible role of FCM for immediate evaluation of pancreatic specimens from EUS-FNB. It involved comparison of the interobserver agreement between the new method and standard histological analysis during international multicenter sharing of digital images. Digital images from 25 cases of EUS-FNB obtained with real-time FCM technology and 25 paired digital whole-slide images from permanent conventional paraffin sections were observed by 10 pathologists from different Institutions in Europe, Japan, and the United States, in a blinded manner. The study evaluated 500 observations regarding adequacy, morphological clues, diagnostic categories, and final diagnosis.

FINDINGS

Statistical analysis showed substantial equivalence in the interobserver agreement among pathologists using the two techniques. There was also good inter-test agreement in determining sample adequacy and when assigning a diagnostic category. Among morphological features, nuclear enlargement was the most reproducible clue, with very good inter-test agreement.

INTERPRETATION

Findings in this study are from international multicenter digital sharing and are published here for the first time. Considering the advantages of FCM digital diagnostics in terms of reduced time and unaltered sample maintenance, the ex vivo confocal laser microscopy may effectively improve traditional EUS-FNB diagnostics, with significant implications for planning modern diagnostic workflow for pancreatic tumors.

FUNDING

This study was not supported by any funding source.

Ex Vivo Fluorescence Confocal Microscopy (FCM) Ensures Representative Tissue in Prostate Cancer Biobanking: A Feasibility Study

Background: Biobanking of prostate carcinoma is particularly challenging due to the actual cancer within the organ often without clear margins. Frozen sections are to date the only way to examine the biobank material for its tumor content. We used ex vivo fluorescence confocal microscopy (FCM) to analyze biobank samples prior to cryoasservation. Methods: 127 punch biopsies were acquired from prostatectomy-specimens from 40 patients. These biopsies were analyzed with a Vivascope 2500-G4 prior to their transfer to the biobank. In difficult cases, larger samples of the prostatectomy specimens were FCM scanned in order to locate tumor foci. After patient acquisition, all samples were taken from the biobank and analyzed. We compared the results of the FCM examinations with the results of conventional histology and measured the DNA content. Results: With upstream FCM, the tumor content of biobank samples could be determined with high confidence. The detection rate of representative biobank samples was increased due to the rapid feedback. The biobank samples were suitable for further molecular analysis. Conclusion: FCM allows for the first time lossless microscopic analysis of biobank samples prior to their cryoasservation and guarantees representative tumor and normal tissue for further molecular analysis.