18F-fluorocholine PET/CT detects parathyroid gland hyperplasia as well as adenoma: 401 PET/CTs in one center.

BACKGROUND: During the past decade, 18F-fluorocholine (FCH) PET/CT has been continuously performed at Tenon Hospital (Paris, France) for the detection of hyperfunctioning parathyroid glands (PT). METHODS: A cohort of 401 patients, deliberately referred for HPT since September 2012, has been analyzed. The aim of this real-life retrospective study was to determine the diagnostic utility of FCH in this setting, overall and in subgroups according to the type of hyperparathyroidism (HPT), the context of FCH in the imaging work-up and in the patient's history: initial imaging or persistence or recurrence after previous parathyroidectomy (PTX). The influence of the histologic type of resected PTs, hyperplasia or adenoma, on the preoperatory detection on FCH PET/CT has been studied as well. RESULTS: Four hundred one FCH PET/CTs were included in the cohort, performed in 323 patients with primary HPT (pHPT), including 18 with familial HPT (fHPT), and in 78 patients with secondary renal HPT (rHPT). The overall positivity rate in the 401 FCH PET/CTs was 73%. The PTX rate was twice greater in patients whose FCH PET/CT was positive than negative (73% vs. 35%). Abnormal PT(s) were pathology proven in 214 patients: only hyperplastic gland(s) in 75 cases and at least one adenoma in 136 cases; FCH PET/CT sensitivity was 89% and 92%, respectively. Similarly, there was no significant difference in patient-based sensitivity whether FCH PET/CT was performed as 1st line or later in the imaging work-up, or indicated for initial imaging or for suspicion of persistent or recurrent HPT. Gland-based sensitivity was significantly lower for hyperplasia than for adenoma (72% and 86%, respectively). The lowest gland-based sensitivity value was 65%, observed in case of hyperplasia and when FCH was performed late in the imaging work-up. FCH PET/CT correctly showed multiglandular HPT (MGD) in 36/61 proven cases, 59%. Results of ultrasonography (US) and 99mTc-sestaMIBI (MIBI) imaging were available in 346 and 178 patients, respectively. For both modalities, the corresponding sensitivity values were significantly less than those of FCH PET/CT (e.g., overall gland-based sensitivity 78% for FCH, 45% for US, 30% for MIBI) and MGD was detected in 32% of cases by US and 15% by MIBI. CONCLUSIONS: Although FCH PET/CT has been performed since 2017 as 1st line imaging for HPT at Tenon Hospital (Paris, France), a large majority of patients underwent prior US and/or MIBI in their preoperative work-up. Therefore, a selection bias is very likely, as most patients referred to FCH PET/CT had non-conclusive or discordant results of US and MIBI, explaining the low performance of those modalities in the present cohort compared to published results. Nevertheless, the superiority of FCH PET/CT over US and MIBI in detecting abnormal PTs reported in various comparative studies is definitely confirmed in this larger real-life cohort. The detection with FCH PET/CT of hyperplastic PTs was somewhat lower than that of adenomas but was better than using US or MIBI. The present results lead to recommend FCH PET/CT as the first line imaging modality in HPT when it is widely available or, if less available, at least in HPT with predominance of hyperplasia and/or MGD.

FCH-PET/CT in Primary Hyperparathyroidism With Discordant/Negative MIBI Scintigraphy and Ultrasonography.

CONTEXT: The contribution of [18F]F-fluorocholine (FCH)-positron emission tomography (PET)/computed tomography (CT) in normocalcemic primary hyperparathyroidism (nPHPT) remains unknown. OBJECTIVE: To evaluate the sensitivity and specificity of FCH-PET/CT in a cohort of osteoporotic patients with nPHPT and discordant or negative [99mTc]Tc-sestamibi scintigraphy and ultrasonography who all underwent parathyroidectomy (PTX). DESIGN: Longitudinal retrospective cohort study in patients referred for osteoporosis with mild biological primary hyperparathyroidism. SETTING: Tertiary referral center with expertise in bone metabolism and surgical management of hyperparathyroidism. PATIENTS: Among 109 patients with PHPT analyzed, 3 groups were individualized according to total serum calcium (tCa) and ionized calcium (iCa): 32 patients with hypercalcemia (HtCa group), 39 patients with normal tCa and elevated iCa (NtCa group), and 38 patients with both normal tCa and iCa (NiCa). All patients had biochemical follow-up confirming or not the success of PTX. MAIN OUTCOME MEASURES: To evaluate the performance of FCH-PET/CT in terms of sensitivity and specificity, and to compare with first-line imaging procedures in the setting of nPHPT. RESULTS: The sensitivity of FCH-PET/CT was 67% in the hypercalcemic group, 48% in the NtCa group (P = .05 vs HtCa), and 33% in the NiCa group (P = .004 vs HtCa). Specificity ranged from 97% to 99%. FCH-PET/CT was positive in 64.3% of patients with negative conventional imaging, with biochemical resolution after PTX in 77.8% of patients. Triple negative imaging was observed in 20 patients, with PHPT resolution in 85% of these patients. CONCLUSION: This study highlights the contribution of FCH-PET/CT in a well-phenotyped cohort of normocalcemic patients with discordant or negative findings in [99mTc]Tc-sestamibi scintigraphy and ultrasonography. However, negative imaging in nPHPT does not rule out the possibility of surgical cure by an experienced surgeon.

18F-fluorocholine PET/CT and conventional imaging in primary hyperparathyroidism.

PURPOSE: The purpose of this study was to assess the diagnostic capabilities of preoperative conventional imaging (99mTc-MIBI scintigraphy, cervical ultrasonography [CUS]) and 18F-fluorocholine PET/CT (FCH PET/CT) in the detection of hyperfunctioning parathyroid gland in patients with primary hyperparathyroidism (PHPT) used alone or as a single imaging set. MATERIALS AND METHODS: A total of 51 consecutive patients (6 men, 45 women; mean age, 62 ± 11.6 [SD] years; age range: 28-86 years) with biochemically confirmed PHPT who underwent CUS, single-tracer dual phase 99mTc-MIBI scintigraphy and FCH PET/CT were retrospectively included. 99mTc-MIBI scintigraphy were performed immediately after CUS and interpreted by the same operators. FCH PET/CT examinations were interpreted independently by two nuclear medicine physicians. An additional reading session integrating the three imaging modalities read in consensus as a combined imaging set was performed. RESULTS: At surgery, 74 lesions were removed (32 parathyroid adenomas, 38 parathyroid hyperplasia and 4 subnormal glands). Thirty-six patients (71%) had single-gland disease and 15 patients (29%) had multiglandular disease at histopathological analysis. On a patient basis, sensitivity and accuracy of FCH PET/CT, CUS and 99mTc-MIBI scintigraphy for the detection of abnormal parathyroid glands were 76% (95% CI: 63-87%) and 76% (95% CI: 63-87%), 71% (95% CI: 56-83%) and 71% (95% CI: 56-83%), 33% (95% CI: 21-48%) and 33% (95% CI: 21-48%), respectively. The sensitivity of the combined imaging set was 94% (95% CI: 84-99%) and greater than the sensitivity of each individual imaging technique (P ≤ 0.001 for all). CONCLUSION: Our results suggest that CUS, 99mTc-MIBI scintigraphy and FCH PET/CT interpreted as a single imaging set could be the ideal practice to precisely localize parathyroid lesion in patients with PHPT before surgery.

18F-fluorocholine PET/CT in MEN1 Patients with Primary Hyperparathyroidism.

BACKGROUND: Primary hyperparathyroidism (HPT1) is the most frequent endocrinopathy in multiple endocrine neoplasia type 1 (MEN1). Its surgical management is challenging. We aimed to describe and compare the imaging findings of parathyroid ultrasound (US), sestaMIBI scintigraphy (sestaMIBI), and 18F-fluorocholine (FCH) PET/CT in a series of MEN1 patients with HPT1. METHODS: Retrospective analysis of a cohort of MEN1 patients with HPT1 assessed by parathyroid US, sestaMIBI scintigraphy and SPECT/CT, and FCH-PET/CT for potential surgery between 2015 and 2019. RESULTS: Twenty-two patients with a confirmed diagnosis of MEN1 who presented with HPT1 and were assessed by the 3 imaging modalities were included. After imaging workups, 11 patients were operated on for the first time, 4 underwent a redo surgery, and 7 did not undergo an operation. The overall patient-based positivity rate of imaging was 91% (20 of 22) for parathyroid US and 96% (21 of 22) for both sestaMIBI and FCH-PET/CT. The 3 imaging modalities demonstrated negative findings in 1/22 patient who did not undergo surgery. Overall, 3 pathologic glands were not detected by any imaging technique. SestaMIBI and FCH-PET/CT both resulted in the same 3 false-positive results in ectopic areas with a significant uptake on two thymic carcinoid tumors and one inflammatory lymph node. FCH-PET/CT provided more surgically relevant data than sestaMIBI in 4/11 patients with initial surgery and in 1/4 patient who underwent redo surgery. CONCLUSIONS: Compared to sestaMIBI scintigraphy, FCH-PET/CT provides additional information regarding the number of pathologic parathyroid glands and their localization in MEN1 patients with HPT1.

18F-Fluorocholine PET/CT Imaging of Brown Tumors in a Patient With Severe Primary Hyperparathyroidism.

Brown tumors are rare skeletal anomalies occurring in patients with hyperparathyroidism and exposing patients to pathological fractures. We report the case of a 26-year-old woman with severe primary hyperparathyroidism (calcemia, 2.9 mmol/L; parathyroid hormone, 59 pmol/L) who underwent F-fluorocholine (FCH) PET/CT before parathyroidectomy. FCH PET localized the hyperfunctioning parathyroid gland and showed multiple foci in correspondence with bone lytic lesions on CT. Those lesions were not visible on the Tc-MIBI dual-phase scintigraphy. The pathology of one of the FCH-positive bone lesions corresponded to a brown tumor related to hyperparathyroidism.

18F-Fluorocholine PET/CT and Parathyroid 4D Computed Tomography for Primary Hyperparathyroidism: The Challenge of Reoperative Patients.

BACKGROUND: To evaluate FCH-PET/CT and parathyroid 4D-CT so as to guide surgery in patients with primary hyperparathyroidism (pHPT) and prior neck surgery. METHODS: Medical records of all patients referred for a FCH-PET/CT in our institution were systematically reviewed. Only patients with pHPT, a history of neck surgery (for pHPT or another reason) and an indication of reoperation were included. All patients had parathyroid ultrasound (US) and Tc-99m-sestaMIBI scintigraphy, and furthermore, some patients had 4D-CT. Gold standard was defined by pathological findings and/or US-guided fine-needle aspiration with PTH level measurement in the washing liquid. RESULTS: Twenty-nine patients were included in this retrospective study. FCH-PET/CT identified 34 abnormal foci including 19 ectopic localizations. 4D-CT, performed in 20 patients, detected 11 abnormal glands at first reading and 6 more under FCH-PET/CT guidance. US and Tc-99m-sestaMIBI found concordant foci in 8/29 patients. Gold standard was obtained for 32 abnormal FCH-PET/CT foci in 27 patients. On a per-lesion analysis, sensitivity, specificity, positive and negative predictive values were, respectively, 96%, 13%, 77% and 50% for FCH-PET/CT, 75%, 40%, 80% and 33% for 4D-CT. On a per-patient analysis, sensitivity was 85% for FCH-PET/CT and 63% for 4D-CT. FCH-PET/CT results made it possible to successfully remove an abnormal gland in 21 patients, including 12 with a negative or discordant US/Tc-99m-sestaMIBI scintigraphy result, with a global cure rate of 73%. CONCLUSION: FCH-PET/CT is a promising tool in the challenging population of reoperative patients with pHPT. Parathyroid 4D-CT appears as a confirmatory imaging modality.

Hyperparathyroidism in octogenarians: A plea for ambulatory minimally invasive surgery under local anesthesia.

BACKGROUND: With the current aging of the world's population, diagnosis of primary hyperparathyroidism is being reported in increasingly older patients, with the associated functional symptomatology exacerbating the vicissitudes of age. This retrospective study was designed to establish functional improvements in older patients following parathyroid adenomectomy under local anesthesia as outpatient surgery. MATERIALS AND METHODS: Data were collected from 53 patients aged 80 years or older who underwent a minimally invasive parathyroid adenomectomy. All patients underwent a preoperative ultrasound, scintigraphy, and were monitored for the effectiveness of the procedure according to intra- and postdosage of parathyroid hormone (PTH) at 5min, 2h and 4h. RESULTS: Mean preoperative serum calcium level was 2.8mmol/L (112mg/L) and mean PTH was 180pg/ml. Thirty-eight patients were operated under local anesthesia using minimally invasive surgery and 18 patients were operated under general anesthesia. In 26 cases, the procedure was planned on an outpatient basis but could only be carried out in 21 patients. Fifty-one patients had normal serum calcium and PTH levels during the immediate postoperative period. Two patients were reoperated under general anesthesia, since immediate postoperative PTH did not return to normal. Four patients died due to reasons unrelated to hyperparathyroidism. Five patients were lost to follow-up six months to two years postsurgery. Of the 44 patients (83%) with long-term monitoring for PTH, none had recurrence of biological hyperparathyroidism. Excluding the three asymptomatic patients, 38 of the 41 symptomatic patients (93%) with long-term follow-up were considering themselves as "improved" or "strongly improved" after the intervention, notably with respect to fatigue, muscle and bone pain. Two patients (4.9%) reported no difference and one patient (2.4%) said her condition had worsened and regretted having undergone surgery. CONCLUSION: In patients 80 years or older, minimally invasive surgery as an outpatient under local anesthesia offered an excellent risk/benefit ratio given its many advantages: simplicity, speed, absence of general anesthesia, ease of monitoring, direct voice control intraoperatively, very low morbidity, effectiveness in treating primary hyperparathyroidism in more than 95% of first intention patients, and the possibility of immediate or delayed recovery in the event of multiglandular disease going unnoticed.

Outpatient thyroid remnant ablation using repeated low 131-iodine activities (740 MBq/20 mCix2) in patients with low-risk differentiated thyroid cancer.

CONTEXT: In low-risk differentiated thyroid cancer (DTC), postoperative (131)I remnant ablation should employ a minimum effective activity; reports increasingly suggest efficacy of low activities, e.g. 1110 MBq/30 mCi. OBJECTIVES, DESIGN, PATIENTS, AND INTERVENTIONS: We retrospectively studied the ablation capability and diagnostic utility of the Minidose protocol, two 740-MBq/20 mCi outpatient administrations, 6-18 months apart, plus related diagnostic procedures, in 160 consecutive (near-) totally thyroidectomized low-risk DTC (pT1/N0-Nx) patients. Successful ablation comprised negative 740-MBq whole-body scintigraphy with cervical uptake below 0.1%, negative stimulated thyroglobulin (STg) (<1 ng/ml, negative thyroglobulin antibodies), and negative Doppler ultrasonography (performed around Minidose 2). SETTING: The study took place at a referral center. RESULTS: Minidose imaging found unsuspected nodal or distant metastases in nine of 160 patients (5.6%). Ablation success rates after one (two) 740-MBq activity (activites) were 75.9% (90.2%) in 145 (132) evaluable imaging-negative patients. Compared with thyroid hormone withdrawal, recombinant human TSH stimulation was associated with higher urinary iodine excretion/creatinine, lower cervical uptake, and more frequent ablation success after the first 740 MBq; success rates no longer differed significantly after both administrations. Patients with STg below 10 ng/ml at Minidose 1 were oftener ablated at Minidose 2 (odds ratio=13.9, 95% confidence interval=2.5-76.4, P<0.003), attaining 92.0% final ablation success after recombinant human TSH preparation, suggesting that one 740-MBq activity should suffice in this subgroup. All 81 evaluable patients with prolonged follow-up (mean 41.8±21.9 months after Minidose 1) had no evidence of disease at the last visit. CONCLUSIONS: The Minidose outpatient ablation protocol is effective and diagnostically useful in low-risk DTC.

Thyrotoxic periodic paralysis in Caucasian patients: a diagnostic challenge.

Secondary hypokalemic periodic paralysis is rare. However, when it occurs, it is usually associated with Graves' disease and it is mostly diagnosed in Asiatic male patients. In this report, we analyze the diagnostic procedure in three cases of hypokalemic periodic paralysis associated with Graves' disease, diagnosed in three different emergency care units over the last 3 years. Three Caucasian men (26, 30, and 39 years of age) came to the emergency care unit for acute tetraparesia. One of them had suffered 15 stereotypical episodes of tetraparesia during the last 2 years. Goiter was present in each case. Kalemia was 1.8, 2.1, and 3 mmol/l, respectively. Triggering events such as considerable sugar intake and physical exercise were present in two cases. In all cases, low TSH levels, high FT4 levels, and anti-TSH receptor antibodies led to the diagnosis of Graves' disease. All patients were treated with potassium supplementation and neomercazole. Outcome was good with a follow-up of 6, 9, and 24 months, respectively. Emergency care practitioners should be aware of this diagnosis, which may affect Caucasian patients presenting with transient tetraparesia in a primary care unit.

Selection of patients with solitary thyroid nodules for operation.

OBJECTIVE: To improve the preoperative selection for operation of patients with solitary thyroid nodules. DESIGN: Prospective cohort study. SETTING: University hospital, France. PATIENTS: 155 consecutive patients who presented with solitary thyroid nodules and were operated on. INTERVENTIONS: Clinical examination, ultrasound examination, fine needle aspiration biopsy, followed by total thyroid lobectomy with frozen section and final histological examination. MAIN OUTCOME MEASURE: Correct prediction of thyroid carcinoma or benign adenoma. RESULTS: A logistic regression analysis indicated that absence of rim (p < 0.002), solid and hypoechoic feature (p < 0.003) and malignant or suspicious fine needle aspiration biopsy results (p < 0.0001) were significantly associated with malignancy. Selection for operation by the logistic model would save 40 of 73 patients from operation and 40 of 59 from unnecessarily radical operation. It would detect a similar number of cancers as a strategy based solely on fine needle aspiration cytology. CONCLUSIONS: A combination of the available diagnostic methods provides substantial benefit in the preoperative selection of patients with an isolated thyroid nodule.