${}^{68}$Ga-Trivehexin PET/CT. A promising novel tracer for primary hyperparathyroidism

This study aims to assess ${}^{68}$Ga-Trivehexin PET/CT for detecting hyperfunctioning parathyroid tissue in comparison to [${}^{99m}$Tc]Tc-MIBI scintigraphy-SPECT/CT (MIBI scan) in patients with primary hyperparathyroidism (PHPT). The cohort comprised 13 patients diagnosed with PHPT based on biochemical analyses, including serum calcium, phosphorus, and parathyroid hormone (PTH) levels. Each participant underwent cervical ultrasonography, MIBI scan, and ${}^{68}$Ga-Trivehexin PET/CT imaging. Complementary 4D-CT and ${[}^{18}F]$ fluorocholine PET/CT were conducted in 7 patients. Ten lesions of 7 patients underwent PTH wash-out (WO) procedure. ${}^{68}$Ga-Trivehexin PET/CT findings were compared with other modalities and PTH-WO results. Ten patients had sporadic PHPT, while 3 were diagnosed with MEN-1 syndrome-associated PHPT. One patient did not have any identifiable parathyroid lesion across the imaging modalities. On a patient-based analysis, MIBI scan and ${}^{68}$Ga-Trivehexin PET/CT identified parathyroid lesions in 10 and 11 patients, respectively. However, ${}^{68}$Ga-Trivehexin PET/CT detected 7 additional parathyroid lesions that were negative on the MIBI scan. Consequently, 17 lesions were identified and confirmed as hyperfunctioning parathyroid tissue through imaging, PTH-WO, or a combination of both modalities. In lesion-based evaluation, ${}^{68}$Ga-Trivehexin identified 16 lesions compared to 10 by MIBI scan, resulting in a detection rate of 94.1% and 58.8%, respectively. Notably, in three patients who underwent [${}^{18}$F]fluorocholine PET/CT, no lesions were detected; yet ${}^{68}$Ga-Trivehexin PET/CT successfully identified parathyroid lesions in two of these patients. Our study provides the first evidence that ${}^{68}$Ga-Trivehexin PET/CT can effectively identify hyperfunctioning parathyroid tissue with a high detection rate warranting further investigations to comprehensively explore its potential in PHPT management.