Evaluation of Wisconsin and CaPTHUS Indices Usefulness for Predicting Monoglandular and Multiglandular Disease in Patients with Primary Hyperparathyroidism through the Analysis of a Single-Center Experience

Background. The main challenge for treating primary hyperparathyroidism (PHPT) is to understand if it is caused by a single adenoma (80–85% of the cases) or by a multiglandular disease (15–20%), both preoperatively and intraoperatively. For this reason, some preoperative scores were proposed in the literature, to perform focused parathyroidectomy, avoiding intraoperative parathormone assay (ioPTH). The most known are the CaPTHUS test and the Wisconsin index. We applied them to our experience. Methods. A retrospective cohort study on 462 patients referred for parathyroidectomy to Thyroid and Parathyroid Unit at Santi Paolo e Carlo Hospital, Milan, Italy, from 2011 to 2021. Only patients affected with benign PHPT and neck ultrasound performed at our institution were included. Both patients for whom preoperative imaging agreed with the localization of a single diseased parathyroid and those with only ultrasound or scintigraphy positive for parathyroid localization underwent Mini-Invasive Video-assisted parathyroidectomy. In all cases, ioPTH assay was performed. The conversion to bilateral neck exploration was decided based on the drop in ioPTH. CaPTHUS score and the Wisconsin index (Win) were applied to the series. CaPTHUS score ≥3 and Win index >1600, according to the original studies of the literature, were considered at high probability of monoglandular disease. Outcomes in these two groups were examined. Results. 236 patients were eligible for the study. The pathology resulted in multiglandular disease in 24 patients (10.2%). Among these, 18 (75.0%) obtained a CaPTHUS score ≥3, and 20 (83.3%) had a Win index>1600. Intraoperative PTH allowed to identify multiglandular disease in 16 of 18 cases with CaPTHUS ≥3 and in 18 of 20 cases with win >1600, who could have been lost, based only on the results of these 2 tests. Conclusion. Based on our experience, CaPTHUS test and Wisconsin index were not so useful in predicting multiglandular disease as ioPTH.

Comparison of the diagnostic accuracy of 18F-Fluorocholine PET and 11C-Methionine PET for parathyroid localization in primary hyperparathyroidism: a systematic review and meta-analysis

Background. Primary hyperparathyroidism is characterized by an autonomous hypersecretion of parathyroid hormone by one or more parathyroid glands. Preoperative localization of the affected gland(s) is of key importance in order to allow minimally invasive surgery. At the moment, 11C-Methionine and 18F-Fluorocholine PET studies appear to be among the most promising second-line localization techniques; their comparative diagnostic performance, however, is still unknown. Methods. PubMed/Medline and Embase databases were searched up to October 2020 for studies estimating the diagnostic accuracy of 11C-Methionine PET or 18F-Fluorocholine PET for parathyroid localization in patients with primary hyperparathyroidism. Pooled sensitivity and positive predictive value were calculated for each tracer on a “per-lesion” basis and then compared using a random-effect model subgroup analysis. Results. Twenty-two studies were finally considered in the meta-analysis. Among these, 8 evaluated the diagnostic accuracy of 11C-Methionine and 14 that of 18F-Fluorocholine. No study directly comparing the two tracers was found. The pooled sensitivity of 18F-Fluorocholine was higher than that of 11C-Methionine (92% vs 80%, p < 0.01), while the positive predictive value was similar (95% vs 94%, p = 0.99). These findings were confirmed in multivariable meta-regression models, demonstrating their apparent independence from other possible predictors or confounders at a study level. Conclusion. This was the first meta-analysis that specifically compared the diagnostic accuracy of 11C-Methionine and 18F-Fluorocholine PET for parathyroid localization in patients with primary hyperparathyroidism. Our results suggested a superior performance of 18F-Fluorocholine in terms of sensitivity, while the two tracers had comparable accuracy in terms of positive predictive value.

Routine Use of Preoperative Neck Ultrasound in Primary Hyperparathyroidism Identifies Coexisting Thyroid Disease and Improves Parathyroid Localization

Background In Jan 2018, we began routinely obtaining neck ultrasound (US) with 123I/99Tc-sestamibi (MIBI) for parathyroid gland localization and to identify thyroid pathology in the setting of primary hyperparathyroidism (1HPT). The aim of this study is to assess if routine neck US is a useful adjunct to 123I/99Tc-MIBI in 1HPT. Methods Patients undergoing surgery for 1HPT with both 123I/99Tc-MIBI and US at our institution after implementation of routine US were reviewed. Biopsy and surgical management of thyroid pathology was evaluated. 123I/99Tc-MIBI and US results were compared to intraoperative findings to determine sensitivity and positive predictive value (PPV) for parathyroid localization. Results From January 2018 to September 2019, there were 423 patients (mean, 61 years) that met inclusion criteria (80% women). Thyroid nodules were found on US in 57%, mean size 1.3 + 0.8 cm. Fine needle aspiration (FNA) was performed in 87 patients with nodules (36%). 35 patients (8.5%) required total or partial thyroidectomy for diagnoses/treatment. Papillary thyroid cancer (PTC) was found in 3.5% of the cohort with micro-PTC 53% and PTC 1-2 cm 40%. A successful parathyroid operation for 1HPT was achieved in 98.6% of patients. Positive predictive value for localization of abnormal parathyroid glands was 97% when US and 123I/99Tc-MIBI had concordant findings. Discussion Routine use of US in 1HPT commonly identifies nodules that are benign or low-risk PTC. Ultrasound is less sensitive for parathyroid localization but when used with 123I/99Tc-MIBI, concordant imaging has a high PPV.