Next-generation endomyocardial biopsy: the potential of confocal and super-resolution microscopy

Abstract

Confocal laser scanning microscopy and super-resolution microscopy provide high-contrast and high-resolution fluorescent imaging, which has great potential to increase the diagnostic yield of endomyocardial biopsy (EMB). EMB is currently the gold standard for identification of cardiac allograft rejection, myocarditis, and infiltrative and storage diseases. However, standard analysis is dominated by low-contrast bright-field light and electron microscopy (EM); this lack of contrast makes quantification of pathological features difficult. For example, assessment of cardiac allograft rejection relies on subjective grading of H&E histology, which may lead to diagnostic variability between pathologists. This issue could be solved by utilising the high contrast provided by fluorescence methods such as confocal to quantitatively assess the degree of lymphocytic infiltrate. For infiltrative diseases such as amyloidosis, the nanometre resolution provided by EM can be diagnostic in identifying disease-causing fibrils. The recent advent of super-resolution imaging, particularly direct stochastic optical reconstruction microscopy (dSTORM), provides high-contrast imaging at resolution approaching that of EM. Moreover, dSTORM utilises conventional fluorescence dyes allowing for the same structures to be routinely imaged at the cellular scale and then at the nanoscale. The key benefit of these technologies is that the high contrast facilitates quantitative digital analysis and thereby provides a means to robustly assess critical pathological features. Ultimately, this technology has the ability to provide greater accuracy and precision to EMB assessment, which could result in better outcomes for patients.

Heart Failure Association of the ESC, Heart Failure Society of America and Japanese Heart Failure Society Position statement on endomyocardial biopsy

“…121 Innovations in cardio-pathology, including new-generation PCR tools, confocal laser scanning microscopy and super-resolution microscopy with high-contrast and high-resolution fluorescent imaging, will likely improve the diagnostic yield of EMB. 122 Presently, there is an unmet need to develop a network of regional and national centres with a standardized expertise in EMB practice. This issue can be addressed though the implementation of .…”

Heart Failure Association, Heart Failure Society of America, and Japanese Heart Failure Society Position Statement on Endomyocardial Biopsy

“…Future improvement in technologies is expected to provide more flexible and steerable guidance catheters, as well as the possibility of integrating EMB with highresolution imaging modalities (115). Innovations in cardio-pathology, including newgeneration PCR tools, confocal laser scanning microscopy and super-resolution microscopy with high-contrast and high-resolution fluorescent imaging, will likely improve the diagnostic yield of EMB (116).…”

Recent technical advances in whole slide imaging instrumentation

“…SRM offers two advantages. First, it makes live imaging feasible at the sub‐cellular level, which enables novel, high‐performance diagnostics such as those for platelet granule disorders, 147 renal disorders, 148 cardiac problems, 149 Alzheimer's disease, 150 and so forth. Secondly, it can support low‐cost optical systems towards producing clinical‐grade imaging.…”