PurposeIn this prospective study we compared the accuracy of 18F-fluorocholine PET/CT with that of 99mTc-MIBI or99mTc-tetrofosmin SPECT/CT in the preoperative detection of parathyroid adenoma in patients with primary hyperparathyroidism. We also assessed the value of semiquantitative parameters in differentiating between parathyroid hyperplasia and adenoma.MethodsBoth 18F-fluorocholine PET/CT and 99mTc-MIBI/tetrofosmin SPECT/CT were performed in 100 consecutive patients with biochemical evidence of primary hyperparathyroidism. At least one abnormal focus on either 18F-fluorocholine or 99mTc-MIBI/tetrofosmin corresponding to a parathyroid gland or ectopic parathyroid tissue was considered as a positive finding. In 76 patients with positive findings on at least one imaging modality, surgical exploration was performed within 6 months, and the results were related to histopathological findings and clinical and laboratory findings at 3–6 months as the standard of truth. In 24 patients, no surgery was performed: in 18 patients with positive imaging findings surgery was refused or considered risky, and in 6 patients imaging was negative. Therefore, data from 82 patients (76 undergoing surgery, 6 without surgery) in whom the standard of truth criteria were met, were used in the final analysis.ResultsAll patients showed biochemical evidence of primary hyperparathyroidism with a mean serum calcium level of 2.78 ± 0.34 mmol/l and parathormone (PTH) level of 196.5 ± 236.4 pg/ml. The study results in 76 patients with verified histopathology and 3 patients with negative imaging findings were analysed. Three of six patients with negative imaging showed normalized serum PTH and calcium levels on laboratory follow-up at 3 and 6 months, and the results were considered true negative. In a patient-based analysis, the detection rate with 18F-fluorocholine PET/CT was 93% (76/82), but was only 61% (50/82) with 99mTc-MIBI/tetrofosmin SPECT/CT. In a lesion-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of 18F-fluorocholine PET/CT in the detection of parathyroid adenoma were 93.7%, 96.0%, 90.2%, 97.4% and 95.3%, respectively, and of 99mTc-MIBI/tetrofosmin SPECT/CT were 60.8%, 98.5%, 94.1%, 86.3% and 87.7%, respectively. Although 18F-fluorocholine PET-positive adenomatous lesions showed higher SUVmax values than the hyperplastic glands (6.80 ± 3.78 vs. 4.53 ± 0.40) in the semiquantitative analysis, the difference was not significant (p = 0.236). The mean size (measured as the length of the greatest dimension) and weight of adenomas were 15.9 ± 7.6 mm (median 15 mm, range 1–40 mm) and 1.71 ± 1.86 g (median 1 g, range: 0.25–9 g), respectively. Among the analysed parameters including serum calcium and PTH and the size and weight of parathyroid adenomas, size was significantly different between patients with negative 99mTc-MIBI/tetrofosmin SPECT/CT and those with positive 99mTc-MIBI/tetrofosmin SPECT/CT (mean size 13.4 ± 7.6 mm vs. 16.9 ± 7.4 mm, respectively; p = 0.042)....

Zusammenfassung Grundlagen Die Nebenschilddrüsenszintigrafie nimmt neben der Sonografie einen wichtigen Stellenwert in der präoperativen Lokalisationsdiagnostik von Nebenschilddrüsenadenomen ein. Der nuklearmedizinische diagnostische Standard ist bislang die Technetium-99m-Sestamibi-Szintigrafie. Der Einsatz der Positronenemissionstomographie/Computertomographie (PET/CT) mit Markern des Phospholipidmembranmetabolismus (F-18 Cholin) verspricht auf Basis erster Studien höhere Genauigkeit für die Aufarbeitung des primären Hyperparathyreoidismus als die konventionelle MIBI-2-Phasen-Szintigrafie in planarer, SPECT oder SPECT/CT Technik. Diese Übersicht fasst die Ergebnisse jener Studien zusammen, die mit F-18 Cholin PET/CT durchgeführt wurden. Methodik Es wurde eine selektive Literaturrecherche in PubMed mit den Stichworten "primary hyperparathyroidism and choline", "primary hyperparathyroidism and PET", "parathyroid adenoma and choline" und "parathyroid adenoma and PET" durchgeführt. Ergebnisse Es wurden 6 Studien, die den Einsatz der F-18 Cholin PET/CT beim Hyperparathyreoidismus evaluierten, identifiziert. Diese schlossen 5 bis 151 Patienten ein. Die Studien belegen, dass die Cholin PET/CT hohe Nachweisraten (80 bis 96 %) für solitäre Nebenschilddrüsenadenome aufweist. Vorteile des

The 2-fluorodeoxyglucose positron emission tomography/computed tomography (2-[ 18 F]FDG PET/CT) is used for the evaluation of response to immunotherapy in malignant melanoma. Here, we evaluated the prognostic value of various metabolic parameters in baseline and different time points after therapy. Methods: In this retrospective study, 51 metastatic melanoma patients, who had received immunotherapy, were included. Patients with baseline and two follow-up 2-[ 18 F]FDG PET/CT studies (3 and 6 months after therapy) were selected. Multiple metabolic parameters and tumor-to-background ratios (TBRs) were extracted and correlated with OS. Results: The 3-and 5-year OS rates were 49% and 43.1%, respectively. On baseline 2-[ 18 F]FDG PET/CT, only standardized uptake value corrected for lean body mass (SUL max and SUL peak ), as well as most of the TBRs were predictive for 3-and 5-year OS rates. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and most of the TBRs were predictive on both follow-up studies. Also, the changes in values of MTV, TLG and most of the TBRs from the baseline to the 3-month and 6-month follow-up studies were prognostic. On multivariate analysis, all of the most predictive parameters for OS were derived from the 3-month follow-up study. The ratio of TBR mean to the mediastinum was the best factor (cutoff value of 2.15, sensitivity of 88.5% and specificity of 68.0% for 3year survival). Conclusion: Metabolic parameters derived from 2-[ 18 F]FDG PET/CT are valuable tools for the prediction of 3-and 5-year OS rates in metastatic melanoma patients undergoing immunotherapy. The 3-month follow-up 2-[ 18 F] FDG PET/CT is of particular importance in this regard.

BackgroundAcute myocarditis and acute coronary syndrome (ACS) are important differential diagnoses in patients with new-onset chest pain. To date, no clinical score exists to support the differentiation between these two diseases. The aim of this study was to develop such a score to aid the physician in scenarios where discrimination between myocarditis and ACS appears difficult.Materials and MethodsPatients with ACS (n = 233) and acute myocarditis (n = 123) were retrospectively enrolled. Least absolute shrinkage and selection operator (LASSO) regression was conducted to identify parameters associated with the highest or least probability for acute myocarditis. Logistic regression was conducted using the identified parameters and score points for each level of the predictors were calculated. Cutoffs for the prediction of myocarditis were calculated. Validation was conducted in a separate cohort of 90 patients.ResultsA score for prediction of acute myocarditis was calculated using six parameters [age, previous infection, hyperlipidemia, hypertension, C-reactive protein (CRP), and leukocyte count]. Logistic regression analysis showed a significant association between total score points and the presence of myocarditis (B = 0.9078, p < 0.0001). Cutoff #1 for the prediction of myocarditis was calculated at ≥ 4 (Sens.: 90.3%, Spec.: 93.1%; 46.3% predicted probability for acute myocarditis), cutoff #2 was calculated at ≥ 7 (Sens.: 73.1%, Spec.: > 99.9%; 92.9% pred. prob.). Validation showed good discrimination [area under the curve (AUC) = 0.935] and calibration of the score.ConclusionOur clinical score showed good discrimination and calibration for differentiating patients with acute myocarditis and ACS. Thus, it could support the differential diagnosis between these two disease entities and could facilitate clinical decisions in affected patients.

The aim of the study was to evaluate the clinical impact of pre-ablation rhTSH-stimulated fluorine-18 fluorodeoxyglucose (F-18 FDG) PET/CT in addition to post-therapeutic whole body radioiodine scanning in patients with intermediate to high risk differentiated thyroid carcinoma (DTC). This was a retrospective single center study including 73 patients with thyroid cancer (44 females, mean age 43.2±16.2 years, 62% papillary, 31% follicular, 7% poorly differentiated). All patients underwent ablative radioiodine treatment (mean activity: 3661±673 MBq I-131) using rhTSH after thyroidectomy and lymph node (LN) dissection (01/2013–10/2016) and TSH-stimulated F-18 FDG PET/CT (4 MBq/kg body weight, low dose CT). Post-treatment I-131 whole body scan (I-131 WBS) was obtained 9 days afterwards in planar technique and in case of equivocal or abnormal findings using SPECT/CT. Thirty-one patients (42%) showed F-18 FDG avid lesions, 14 patients showed more FDG than iodine positive lesions and 5 patients more iodine positive lesions in I-131 WBS, respectively. Fifty-three patients showed identical F-18 FDG PET/CT and I-131 WBS. The initial treatment plan was changed from follow-up to therapy (surgery, systemic therapy using tyrosine-kinase inhibition) in 11 patients (15%) on the basis of F-18 FDG PET/CT imaging. Six of these 11 patients had papillary thyroid cancer. Three patients with histologically proven LN metastases had stimulated thyroglobulin-levels<2.0 ng/ml. Our study demonstrated a clinical benefit of pre-ablation rhTSH-stimulated F-18 FDG PET/CT imaging in about 20% of patients with intermediate to high risk DTC, leading to change in patient management in 15%.