Background: In patients with primary hyperparathyroidism (PHPT) locating hyperfunctioning glands (HPGs) is crucial when planning minimally invasive surgery. Dual-isotope subtraction scintigraphy with 99mTc-MIBI/123Iodide using SPECT/CT and planar pinhole imaging (Method A) has previously shown a sensitivity >93%. However, the method is costly and time consuming and entails a high radiation dose. 11C-Choline PET/CT (Method B) is an appealing candidate method unencumbered by these disadvantages. Methods: Sixty patients with newly diagnosed PHPT participated and were scanned using both methods prior to parathyroidectomy. We investigated whether sensitivities of Method A and Method B are similar in a method-to-method comparison when using surgical findings as the true location. Results: At the patient level, sensitivities were (A) 0.98 (95% CI: 0.90–1.00) and (B) 1.00 (95% CI: 0.93–1.00). At the gland level, sensitivities were (A) 0.88 (95% CI: 0.78–0.94) and (B) 0.87 (95% CI: 0.76–0.92). With a non-inferiority margin of ∆ = −0.1, we found a 1-sided p-value < 0.001. Conclusion: Our methods comparison study found that sensitivity of Method B was not inferior to Method A. We suggest that 11C-Choline PET/CT is a clinically relevant first-choice candidate for preoperative imaging of PHPT and that Method B can likely replace Method A in the near future.

Introduction Hyperphosphatemia is associated with increased morbidity and mortality in patients with chronic kidney disease. The aim of this study was to assess whether a meal with high phosphorus content would affect plasma phosphate in the hours that follow among subjects with end-stage kidney disease on peritoneal dialysis. Methods This was a single-blinded randomized cross-over trial of 12 subjects on maintenance peritoneal dialysis, in which subjects were randomized to consume a meal with either high or low phosphorus content on 2 separate trial days. On each trial day, plasma phosphate was measured immediately before consumption of the standardized meal and after 1, 2, 3, and 5 hours. Results The mean fasting plasma phosphate at baseline was 1.69 ± 0.22 mmol/l. Plasma phosphate was similar between the 2 meals at baseline, as well as at 1, 2, 3, and 5 hours after consumption. The largest observed difference in plasma phosphate between the 2 meals was 0.15 mmol/l, which occurred 5 hours after consumption (high-phosphorus meal 1.75 ± 0.32 mmol/l vs. low-phosphorus meal 1.60 ± 0.14 mmol/l ( P = 0.06)). Using summary analyses for repeated measures, we observed a significant difference in the plasma phosphate between the 2 meals ( P = 0.03). Conclusion Our results show that in subjects with end-stage kidney disease, a meal with high phosphorus content has only a negligible effect on plasma phosphate compared to a meal with low phosphorus content. Thus, large increases in plasma phosphate cannot be accounted for by a high intake of phosphorus in the hours before blood sampling.

Objective Preoperative location of hyperfunctioning parathyroid glands (HPGs) is vital when planning minimally invasive surgery in patients with primary hyperparathyroidism (PHPT). Dual‐isotope subtraction scintigraphy with 99mTc‐MIBI/123Iodide using SPECT/CT and planar pinhole imaging (Di‐SPECT) has shown high sensitivity, but is challenged by high radiation dose, time consumption and cost. 11C‐Choline PET/CT (faster with a lower radiation dose) is non‐inferior to Di‐SPECT. We aim to clarify to what extent the two are interchangeable and how often there are discrepancies. Design This is a prospective, GCP‐controlled cohort study. Patients and Measurements One hundred patients diagnosed with PHPT were included and underwent both imaging modalities before parathyroidectomy. Clinical implications of differences between imaging findings and negative imaging results were assessed. Surgical findings confirmed by biochemistry and pathology served as reference standard. Results Among the 90 patients cured by parathyroidectomy, sensitivity was 82% (95% confidence interval [CI]: 74%–88%) and 87% (95% CI: 79%–92%) for Choline PET and Di‐SPECT, respectively, p = .88. In seven cases at least one imaging modality found no HPG. Of these, neither modality found any true HPGs and only two were cured by surgery. When a positive finding in one modality was incorrect, the alternative modality was correct in approximately half of the cases. Conclusion Choline PET and Di‐SPECT performed equally well and are both appropriate as first‐line imaging modalities for preoperative imaging of PHPT. When the first‐line modality fails to locate an HPG, additional preoperative imaging with the alternate modality offers no benefit. However, if parathyroidectomy is unsuccessful, additional imaging with the alternate modality has merit before repeat surgery.

Background Use of 11C-Choline PET/CT is gaining ground in detecting hyperfunctioning parathyroid glands in primary hyperparathyroidism. The purpose of this study was to evaluate the robustness of 11C-Choline PET/CT by assessing intra- and inter-observer agreement to determine whether the method was reader sensitive and therefore should only be performed at highly specialised sites with a high number of cases. PET/CT images of 40 patients diagnosed with primary hyperparathyroidism were anonymised and evaluated three times by three readers: an expert reader and two non-experts (non-experts were experienced in PET/CT imaging, but not in 11C-Choline PET/CT in the setting of primary hyperparathyroidism). Number of hyperfunctioning parathyroid glands, location relative to the thyroid gland and confidence of each assessment (low, moderate or high) were noted, and intra- and inter-observer agreement calculated using Fleiss’ kappa method. Sensitivities and specificities of the non-experts were calculated using the expert reader as gold standard. Results Intra-observer agreement was ‘good’ to ‘near perfect’ for all readers. Inter-observer agreement was good between non-experts and the expert, with kappa values ≥ 0.74. Sensitivities between non-experts and the expert were high, > 81%, when assessing which side and 75% when assessing thyroid quadrant. All specificities were > 94%. Reader certainties were ‘high’ in > 80% of cases for the expert and > 70% and > 65%, respectively for the two non-experts. Conclusion 11C-Choline PET/CT is not reader sensitive for the localisation of hyperfunctioning parathyroid glands and may therefore be safely implemented at sites that have a moderate number of cases. Access to a cyclotron laboratory is, however, a necessity for the production of 11C-Choline. The study was conducted in accordance with the Helsinki 2 declaration and The International Council for Harmonisation Guideline for Good Clinical Practice (ICH_GCP) clinical trial, approved by the Research Ethics Committee of the Capital Region of Denmark (Journal-nr.:H-18012490, date of approval: 18 June 2018) and the Danish Medicines Agency (EudraCT no. 2018-000726-63, date of approval: 6 June 2018). The GCP unit in Eastern Denmark has carried out regular monitoring of the trial according to GCP (ID: 2018-1050).

Objective: The extent of symptoms due to primary hyperparathyroidism depends on the population being studied. Primary hyperparathyroidism is mainly discovered incidentally through routine laboratory findings. Less is known about patient-experienced improvement following successful parathyroidectomy. The aim of our study was to assess changes in Quality of Life after successful surgery using an SF-36 questionnaire. Design: This is a prospective cohort study based on questionnaires. Methods: Forty consecutive patients diagnosed with primary hyperparathyroidism were prospectively administered an SF-36 questionnaire before and 6 months after successful parathyroidectomy. A subgroup of 18 patients answered the questionnaire at 1 and 3 months after surgery. Successful surgery was based on biochemistry and pathology reports as confirmed by an endocrinologist. Results of each SF-36 subcategory were compared to results at baseline in order to detect changes in patient-reported quality of life after successful surgery. Results: There were significant improvements in six of eight SF-36 subcategories: Vitality (P = 0.0001), Physical functioning (P = 0.04), General health perception (P = 0.004), Physical role functioning (P = 0.04), Social role functioning (P = 0.004) and Mental health perception (P = 0.0001). Changes appeared within a month after surgery with no further significant changes at later time points. Conclusions: Parathyroidectomy significantly improves QoL as measured by a decrease in SF-36 scores as early as 1 month after successful parathyroidectomy. The SF-36 QoL questionnaire is suitable for monitoring changes in patient wellbeing after successful parathyroidectomy.