A novel, noninvasive imaging technique for intraoperative assessment of parathyroid glands: Confocal reflectance microscopy

Background. Successful surgical management of primary hyperparathyroidism r equires the ability to identify and distinguish normal from abnormal parath yroid tissue. Microscopic pathologic confirmation often helps with the diag noses and decisions regarding the extent of parathyroid resection. Confocal reflectance microscopy (CRM) is an optical method of noninvasively imaging tissue without fixation, sectioning, and staining as in standard histopath ology. The goal of this study was to determine if CRM imaging could be used to distinguish normal from diseased parathyroid tissue intraoperatively. Methods. In this study, 44 parathyroid glands from 21 patients undergoing o perations for primary hyperparathyroidism were imaged immediately after exc ision. CRM images were compared with conventional hematoxylin-and-eosin sta ined sections obtained from the same gland. The percentage area occupied by fat cells was calculated in images of both normal and diseased glands. Results, Characteristic microscopic features of parathyroid glands were dis tinguishable by CRM and correlated well with, histopathology. The stromal f at content of normal and diseased glands could easily be determined. The pe rcentage area occupied by fat cells differed significantly (P < .00001) in normal glands (average, 23.0% +/- 10.9%) and adenomatous glands (average, 0 .4% +/- 0.7%). Conclusions. CRM imaging rapidly revealed microscopic features that reliabl y differentiated normal and diseased parathyroid glands. The success of thi s preliminary ex vivo study promotes interest in further development of an in situ probe for in vivo clinical diagnostic use.