F18-Choline PET/CT or MIBI SPECT/CT in the Surgical Management of Primary Hyperparathyroidism: A Diagnostic Randomized Clinical Trial.

Importance: Whether F18-choline (FCH) positron emission tomographic (PET)/computed tomographic (CT) scan can replace Tc99m-sestaMIBI (MIBI) single-photon emission (SPE)CT/CT as a first-line imaging technique for preoperative localization of parathyroid adenomas (PTA) in patients with primary hyperparathyroidism (PHPT) is unclear. Objective: To compare first-line FCH PET/CT vs MIBI SPECT/CT for optimal care in patients with PHPT needing parathyroidectomy and to compare the proportions of patients in whom the first-line imaging method resulted in successful minimally invasive parathyroidectomy (MIP) and normalization of calcemia 1 month after surgery. Design, Setting, and Participants: A French multicenter randomized open diagnostic intervention phase 3 trial was conducted. Patients were enrolled from November 2019 to May 2022 and participated up to 6 months after surgery. The study included adults with PHPT and an indication for surgical treatment. Patients with previous parathyroid surgery or multiple endocrine neoplasia type 1 (MEN1) were ineligible. Interventions: Patients were assigned in a 1:1 ratio to receive first-line FCH PET/CT (FCH1) or MIBI SPECT/CT (MIBI1). In the event of negative or inconclusive first-line imaging, they received second-line FCH PET/CT (FCH2) after MIBI1 or MIBI SPECT/CT (MIBI2) after FCH1. All patients underwent surgery under general anesthesia within 12 weeks following the last imaging. Clinical and biologic (serum calcemia and parathyroid hormone levels) assessments were performed 1 and 6 months after surgery. Main Outcomes and Measures: The primary outcome was a true-positive first-line imaging-guided MIP combined with uncorrected serum calcium levels of 2.55 mmol/l or less 1 month after surgery, corresponding to the local upper limit of normality. Results: Overall, 57 patients received FCH1 (n = 29) or MIBI1 (n = 28). The mean (SD) age of patients was 62.8 (12.5) years with 15 male (26%) and 42 female (74%) patients. Baseline patient characteristics were similar between groups. Normocalcemia at 1 month after positive first-line imaging-guided MIP was observed in 23 of 27 patients (85%) in the FCH1 group and 14 of 25 patients (56%) in the MIBI1 group. Sensitivity was 82% (95% CI, 62%-93%) and 63% (95% CI, 42%-80%) for FCH1 and MIBI1, respectively. Follow-up at 6 months with biochemical measures was available in 43 patients, confirming that all patients with normocalcemia at 1 month after surgery still had it at 6 months. No adverse events related to imaging and 4 adverse events related to surgery were reported. Conclusions: This randomized clinical trial found that first-line FCH PET/CT is a suitable and safe replacement for MIBI SPECT/CT. FCH PET/CT leads more patients with PHPT to correct imaging-guided MIP and normocalcemia than MIBI SPECT/CT thanks to its superior sensitivity. Trial Registration: ClinicalTrials.gov Identifier: NCT04040946.

Detection, resection and cure: a systematic review and meta-analysis of 18F-choline PET in primary hyperparathyroidism.

INTRODUCTION: Primary hyperparathyroidism (pHPT) is a common endocrine disorder caused by an autonomous overproduction of parathyroid hormone (PTH) by a parathyroid gland. Over the last decade, 18F-choline (FCH) PET has emerged as a highly performant imaging technique for guiding parathyroidectomy. As cure is the goal of surgery, the main aims of this study were to summarize patient-based sensitivity, positive predictive value (PPV), and cure rate of FCH PET guided surgery in the surgical management of pHPT. EVIDENCE ACQUISITION: We conducted a systematic review and metaanalysis according to the PRISMA Guidelines. A literature search was performed in the PubMed, Web of Science and Cochrane databases, last updated November 2022. Original articles on choline PET in patients with pHPT mentioning patient-based sensitivity, PPV and cure rate were retained. Quality of included studies was assessed using the QUADAS-2 Tool. Patient-based sensitivity, PPV and cure rate were pooled by using a random-effects model. EVIDENCE SYNTHESIS: Twenty-three studies including 1716 patients were included for quantitative assessment. FCH PET showed a pooled patient-based sensitivity of 93.8% (95% CI: 89.8-96.3) and PPV of 97% (95% CI: 92.8-98.8) in patients with pHPT. Parathyroid surgery was performed in 1129 patients. The pooled cure rate of PET-guided surgery was 92.8% (95% CI: 87.4-96.0). Heterogeneity was shown to be moderate for all effect sizes. CONCLUSIONS: FCH PET showed a high patient-based sensitivity, PPV and cure rate of PET guided surgery in patients with pHPT.

Malignancy rate of focal thyroid incidentaloma detected by FDG PET-CT: results of a prospective cohort study.

OBJECTIVE: To evaluate the malignancy rate of focal thyroid incidentaloma (fTI) in a population of patients undergoing a 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) for a non-thyroid purpose. DESIGN: We conducted a prospective cohort study from January 2013 to November 2014. All consecutive patients referred for a FDG PET-CT were prospectively screened. Patients with known neoplastic thyroid disease were excluded from the analysis. All patients presenting one or more fTI and who accepted to benefit from a complementary thyroid ultrasonography (US) were included and managed according to the French endocrine society consensus. Prevalence of fTI in our population and malignancy rate was assessed. RESULTS: During the inclusion period, 10,171 patients were referred for a FDG PET-CT in our center. Fifty-three patients presenting a known thyroid disease were excluded. Among the remaining 10,118 patients, 127 (1.3%) with 131 fTI were individualized. US could not be performed in 37 patients. The remaining 90 patients (92 fTI) were explored by US ± fine-needle aspiration biopsy (FNAB). US results demonstrated a nodule aspect in 80 cases of which 60 benefited from FNAB. Nineteen of 92 fTI underwent surgery with 10 malignant lesions among the 60 patients performing both US and FNAB. CONCLUSION: The prevalence of fTI discovered on FDG PET-CT in our population was 1.3% with 10 malignant lesions among the 60 patients performing both US and FNAB.

Quality of life, clinical outcomes and safety of early prophylactic levothyroxine administration in patients with Graves' hyperthyroidism undergoing radioiodine therapy: a randomized controlled study.

OBJECTIVE: While radioiodine therapy is commonly used for treating Graves' disease, a prolonged and clinical hypothyroidism may result in disabling symptoms leading to deterioration of quality of life (QoL) of patients. Introducing levothyroxine (LT4) treatment in the early post-therapeutic period may be an interesting approach to limit this phenomenon. METHODS: A multicenter, prospective, open-label randomized controlled trial enrolled 94 patients with Graves' hyperthyroidism randomly assigned to the experimental group (n=46) (group A: early prophylactic LT4 treatment) or the control group (n=48) (group B: standard follow-up). The primary endpoint was the 6-month QoL. The secondary endpoints were other QoL scores such as Graves' ophthalmopathy (GO) outcomes, thyroid function tests and safety. RESULTS: The primary endpoint at 6 months was achieved: the mental composite score (MCS) of Short Form 36 (SF-36) was significantly higher in group A compared to group B (P=0.009). Four other dimension scores of the SF-36 and four dimension scores of the thyroid-specific patient-reported outcome (ThyPRO) significantly differed between the two groups, indicating better QoL in group A. After adjustment for variables, the early LT4 administration strategy was found as an independent factor for only two scores of SF-36: the MCS and the general health (GH) score. There were no differences in GO, final thyroid status and changes in the anti-TSH receptor antibodies (TRAbs) levels between the two groups. No adverse cardiovascular event was reported. CONCLUSION: Early LT4 administration post-radioactive iodine (RAI) could represent a safe potential benefit for patients with regard to QoL. The optimal strategy taking into account administered RAI activities and LT4 treatment dosage and timing remains to be determined.

Prognostic value of fluorine-18 fluorodeoxyglucose positron-emission tomography imaging in patients with head and neck squamous cell carcinoma.

BACKGROUND: High tumor uptake of fluorodeoxyglucose (FDG) is associated with an unfavorable outcome in patients with cancer. We evaluated FDG uptake as a prognostic factor in patients with head and neck squamous cell carcinoma. METHODS: Maximum standardized uptake values (SUVmax) of tumor, liver, and pulmonary artery were recorded. Ratios of SUVmax from tumor to liver (T/L) and from tumor to pulmonary artery (T/PA) were calculated for each patient. Clinical data, tumor, and SUVmax ratios were compared with disease-free survival (DFS) and overall survival (OS). RESULTS: Eighty-nine patients were included: 48 presented a local recurrent disease or distant metastases and 42 died. For both DFS and OS, tumor SUVmax value of 7 was the best cutoff value and 4 and 5 for T/L and T/PA ratios. Multivariate analysis confirmed the independent prognostic value of these 3 thresholds for DFS and OS. CONCLUSIONS: FDG uptake has a significant and independent relationship with recurrence and survival.

Clinical and therapeutic impact of 18F-FDG PET/CT whole-body acquisition including lower limbs in patients with malignant melanoma.

OBJECTIVES: To assess the added benefit of scanning lower limbs in addition to the usual whole-body positron emission tomography/computed tomography (PET/CT) scan in patients with no known or suspected primary or metastatic melanoma involving the lower limbs. MATERIALS AND METHODS: This is a retrospective study of 122 consecutive patients [174 2-[¹8F]-fluoro-2-deoxy-D-glucose (FDG) PET/CT] who underwent FDG PET/CT for staging of melanoma at different time points in the course of the disease from October 2005 to February 2009 at the Brest University Hospital. Reports of whole-body PET/CT scans including lower limbs were reviewed. PET/CT abnormalities on the lower extremities were tabulated by location and correlated with pathology, other imaging studies and at least a 6-month clinical follow-up. The usefulness of lower limbs acquisition in clinical management was evaluated according to imagery findings. RESULTS: Among the 174 consecutive PET/CT scans performed in 122 patients, 33 scans in 28 patients highlighted abnormal FDG uptakes considered as equivocal or suggestive of malignancy in the lower limbs. In 28 cases, uptakes were located at once in the lower limbs and in the rest of the body (lung, liver, mediastinal and sub-diaphragmatic lymph nodes, adrenal glands, bone) corresponding to disseminated disease. In five cases, PET/CT uptakes were located only in lower limbs; each pathological uptake corresponded to benign lesions. Lower limbs findings never impacted clinical and therapeutic decision. CONCLUSION: Lower limbs additional PET/CT acquisition seems to offer poor additional benefit with none unexpected lesion detected and routine skull base to upper thigh images might be sufficient for this subset of patients.

Optimized radioiodine therapy for Graves' disease: two MIRD-based models for the computation of patient-specific therapeutic 131I activity.

AIM: (131)I therapy is increasingly used for Graves' hyperthyroidism. Debate remains about the best method for calculating the activity to administer, as well as about the potential benefit of such computed activity. Several arguments plead, nevertheless, in favour of a personalized computation, such as inter-individual variations of thyroid volume and biokinetics. METHODS: A MIRD-based dosimetric approach, with an additional extension that takes into account the variation of thyroid mass during the treatment, has been developed. This approach includes the benefits of a personalized determination of biokinetics. Results were compared with those of six methods widely used in routine practice. Forty-one patients were enrolled (34 women, seven men; mean age +/-SD: 48.11 +/- 6.4 years). (131)I uptakes were measured at 4, 24 and 96 h (36.2 +/- 14.6%, 42.8 +/- 9.7% and 27.6 +/- 6.8%, respectively), following administration of the tracer. The kinetics of iodine in the thyroid were evaluated using a two-compartment model (effective half-life of 5.1 +/- 1.6 days). Computations of activities to deliver the doses prescribed by the physician were done with the eight formalisms. RESULTS: There was no statistical difference between results of the two MIRD-based formalisms (227 +/- 148 MBq and 213 +/- 124 MBq), which were also not significantly different from those obtained with the majority of the other methods (from 128 +/- 95 MBq to 275 +/- 223 MBq). However, a large intra-individual difference up to a factor of 2 between two given methods was found. CONCLUSION: The formalism developed appears to be a good compromise between all the common formalisms already used in many institutions. Furthermore, it allows the exposures of target volumes and non-target volumes to be planned individually and practical individual radiation protection recommendations to be implemented.

Octreotide imaging plus bone scintigrams to optimally localize gastroenteropancreatic neuroendocrine tumors.

PURPOSE: In-111 pentetreotide (Octreotide) is highly sensitive for detecting gastroenteropancreatic neuroendocrine tumors and their metastases. However, a lack of landmarks makes it difficult to localize them anatomically. To overcome this difficulty, the authors simultaneously obtained Octreotide and bone tomoscintigrams, in addition to standard planar images. They used a bicolor scale to display pairs of scintigrams to easily identify the distribution of both tracers. METHODS: Twenty-one hours after Octreotide injection, Tc-99m MDP was also administered to the patients. Three hours later, dual-energy planar and tomographic data were acquired simultaneously. The latter were reconstructed using a filtered back-projection algorithm using a Metz filter. Both sets of data were displayed simultaneously using a bicolor scale, such that Octreotide data appear in green and bone data in red. RESULTS: Planar, tomographic, and three-dimensional data were obtained. With this approach, foci of abnormal uptake are localized more precisely. Hard data can be transmitted easily to referring physicians, who appreciate this compact and efficient means to locate foci of abnormal uptake, especially during surgery planning. However, this method is not well suited to the visualization of small lesions with low Octreotide uptake because the intensity range is drastically reduced. Such lesions are better seen on Octreotide planar images and standard tomoscintigrams. CONCLUSIONS: This approach, which involves only standard image processing, provides landmarks to easily localize significant Octreotide uptake. It can be implemented readily in most nuclear medicine workstations. It complements but does not replace the usual method to display Octreotide data.