Instant Intraoperative Histopathological Assessment of Fresh Parathyroid Tissue: Higher Harmonic Generation Microscopy as a Potential Alternative to Frozen Section.

Background: Hypoparathyroidism is a complication associated with significant morbidity and results from inadvertent removal of the parathyroid during thyroid surgery. Therefore, intra-operative identification of parathyroid tissue is essential to minimize the risk of hypoparathyroidism. Current identification techniques come with significant limitations in logistics and accuracy. We therefore propose higher-harmonic generation microscopy (HHGM), a rapid, non-invasive, label-free method for the real-time visualization of human tissue, as a potential alternative.

Methods: A prospective proof-of-concept study was conducted at the Amsterdam University Medical Centers from February to April 2024. Intra-operative HHGM imaging of presumed parathyroid tissue samples was performed, and the results were compared with conventional histopathology by an expert endocrine pathologist in order to evaluate the sensitivity and specificity of HHGM. The logistical process and its potentially associated benefits were also evaluated.

Results: Intraoperative imaging was performed on 32 fresh, unprocessed tissue samples from 18 patients. HHGM demonstrated a high sensitivity (85%) and specificity (83.3%) for the detection of parathyroid tissue. HHGM imaging was found to be more time-efficient than frozen section, taking ~5 min per biopsy compared to 30 min for FS. HHGM was able to produce high-quality images in cases where frozen section analysis was inconclusive due to insufficient tissue. Logistical challenges and extra workload associated with HHGM were minimal.

Conclusion: This proof-of-concept study demonstrates that HHGM could be a promising intraoperative diagnostic imaging modality, offering rapid imaging and detailed visualization capabilities. These features suggest that HHGM might potentially reduce surgery duration and decrease demand on pathology resources.