Intraoperative Near-Infrared Autofluorescence and Indocyanine Green Imaging to Identify Parathyroid Glands: A Comparison

Objective. To investigate the feasibility of near-infrared autofluorescence (AF) and indocyanine green (ICG) fluorescence to identify parathyroid glands intraoperatively. Methods. Fluorescence imaging was carried out during open parathyroid and thyroid surgery. After visual identification, parathyroid glands were exposed to near-infrared (NIR) light with a wavelength between 690 and 770 nm. The camera of the Storz (R) NIR/ICG endoscopic system used detects NIR light as a blue signal. Therefore, parathyroid AF was expected to be displayed in the blue color channel in contrast to the surrounding tissue. Following AF imaging, a bolus of 5 mg ICG was applied intravenously. ICG fluorescence was detected using the same NIR/ICG imaging system. Well-vascularized parathyroid glands were expected to show a strong fluorescence in contrast to surrounding lymphatic and adipose tissue. Results. We investigated 78 parathyroid glands from 50 patients. 64 parathyroid glands (82%) displayed AF showing the typical bluish violet color. 63 parathyroid glands (81%) showed a strong and persistent fluorescence after application of ICG. The sensitivity of identifying a parathyroid gland by AF was 82% (64 true positive and 14 false negative results), while ICG imaging showed a sensitivity of 81% (63 true positive and 15 false negative results). The Fisher exact test revealed no significant difference between both groups at p < 0.05. Neither lymph nodes nor adipose tissue revealed substantial AF or ICG fluorescence. Conclusion. AF and ICG fluorescence reveal a high degree of sensitivity in identifying parathyroid glands. Further, ICG imaging facilitates the assessment of parathyroid perfusion. However, in the current setting both techniques are not suitable as screening tools to identify parathyroid glands at an early stage of the operation

A pitfall of bilateral inferior petrosal sinus sampling in cyclic Cushing's syndrome

Background: Clinical care of patients with cyclic Cushing's syndrome (CS) is challenging. Classical pitfalls include incorrect subtyping, unnecessary surgical procedures and delayed definite treatment. Case presentation: A 43-year-old female suffered from a rapidly cycling ectopic CS. She experienced six cycles of severe hypercortisolism within a 2 year period (maximum plasma cortisol 5316 nmol/L, normal range 124.2-662.4 nmol/L; maximum urinary free cortisol 79,469 nmol/24 h, normal range < 414 nmol/24 h) lasting 2-9 weeks. The episodes were associated with pronounced hypokalemia (lowest K+ value recorded 2.4 mmol/l) and progressive signs and symptoms of CS. A bilateral inferior petrosal sinus sampling (BIPSS) performed during a trough phase was false positive for pituitary ACTH overproduction resulting in unnecessary transsphenoidal surgery while a second BIPSS performed during an active phase was indicative for ectopic CS. The 18F-DOPA PET/CT showed a pancreatic lesion, which was subsequently partially removed. Surprisingly, the histopathology was conclusive for ACTH-positive lymph node metastasis located in the retro-duodenal tissue of an occult neuroendocrine tumor WHO grade II. The primary tumor has not been identified so far and, because of the persistent hypercortisolism, the patient underwent bilateral adrenalectomy. Two years later, ACTH levels started to increase progressively. Percutaneous biopsy of a newly identified suspected lesion in the fifth thoracic vertebra revealed a metastasis with positive staining for ACTH, synaptophysin and chromogranin A. Therapy with carboplatin and etoposide was started and, since then, the patient underwent 12 cycles of chemotherapy. Conclusions: We report the challenging case of a rapidly cycling CS secondary to ACTH-secreting neuroendocrine intestinal tumor of unknown primary. We highlight the importance of performing diagnostic tests only during the phases of active cortisol secretion and as soon as first symptoms appear to avoid pitfalls

Parathyroid Autofluorescence—How Does It Affect Parathyroid and Thyroid Surgery? A 5 Year Experience

Injury to parathyroid glands during thyroid and parathyroid surgery is common and postoperative hypoparathyroidism represents a serious complication. Parathyroid glands possess a unique autofluorescence in the near-infrared spectrum which could be used for their identification and protection at an early stage of the operation. In the present study parathyroid autofluorescence was visualized intraoperatively using a standard Storz laparoscopic near-infrared/indocyanine green (NIR/ICG) imaging system with minor modifications to the xenon light source (filtered to emit 690 nm to 790 nm light, less than 1% in the red and green above 470 nm and no blue light). During exposure to NIR light parathyroid tissue was expected to show autofluorescence at 820 nm, captured in the blue channel of the camera. Over a period of 5 years, we investigated 205 parathyroid glands from 117 patients. 179 (87.3%) glands were correctly identified by their autofluorescence. Surrounding structures such as thyroid, lymph nodes, muscle, or adipose tissue did not reveal substantial autofluorescence. We conclude that parathyroid glands can be identified by their unique autofluorescence at an early stage of the operation. This may help to preserve these fragile structures and their vascularization and lower the rate of postoperative hypocalcemia

Lack of influence of somatic mutations on steroid gradients during adrenal vein sampling in aldosterone-producing adenoma patients

ObjectiveAdrenal vein sampling (AVS) is a technically demanding procedure required for the identification of suitable candidates for unilateral adrenalectomy in primary aldosteronism. Recently, somaticKCNJ5K+-channel mutations in aldosterone-producing adenoma (APA) patients have been shown to influence steroid gradients during AVS. These and other recently identified genetic modifiers (ATP1A1andATP2B3) might affect the final diagnosis and treatment of the affected patients.DesignFifty-nine patients with APAs who had undergone successful AVS (adrenal vein cortisol:peripheral cortisol ratio ≥2) and had undergone a mutation analysis of their tumor tissue were studied. The mutation status of the APAs was as follows: 19KCNJ5mutations, eight ATPase mutations (fiveATP1A1and threeATP2B3), and 32 patients with none of these mutations.MethodsThe lateralization index (ratio of aldosterone:cortisol on the side of the adenoma to aldosterone to cortisol on the contralateral side) and the contralateral suppression index (ratio of aldosterone:cortisol on the contralateral side to aldosterone to cortisol in the periphery) were calculated for theKCNJ5-mutated, ATPase-mutated, and theKCNJ5/ATPase mutation-negative APA patients.ResultsThe lateralization indices of the ATPase mutation carriers had a median of 19.9 compared with a median of 16.0 in theKCNJ5mutation carriers and that of 20.5 in theKCNJ5/ATPase mutation-negative patients. The contralateral suppression indices of the ATPase-mutated patients had a median of 0.1 compared with a median of 0.4 in theKCNJ5mutation carriers and that of 0.2 in theKCNJ5/ATPase mutation-negative patients. The differences between the genetic groups were not statistically significant.ConclusionsWe did not find evidence for a clinically important impact of mutation status on steroid gradients during AVS.</jats:sec