12:08 CET
309 - Thyroid - Rapid Fire Session: Thyroid and Parathyroid
Conventional & Specialised Nuclear Medicine Clinical Oncology
Sunday, October 13, 11:30 - 12:45
Type of session: Parallel Session
Topic: Conventional & Specialised Nuclear Medicine, Clinical Oncology
Sub topic: 902 Thyroid (Benign), 703 Thyroid, 901 Endocrinology
Chairperson: A. Campennì (/IT)

The role of thyroid scintigraphy with Tc-99m in the era of FNAC and molecular markers
S. Sophocleous;
Diagnostic center Agios Therissos, Strovolos, Nicosia, CYPRUS.

Aim/Introduction: BACKGROUND
In Cyprus with known iodine deficiency, thyroid nodules are found in ~15% of the adults. Recent investigations show that approximately 10% of them are malignant, mainly diagnosed with FNAC. The use of thyroid scintigraphy in the work-up of thyroid nodules has been dramatically decreased during last years. It is only used in cases with low TSH level. Consequently autonomous functioning thyroid nodules (AFNT) with normal TSH are rarely diagnosed and the number of unnecessary performed FNAC on these lesions is unknown.
Materials and Methods: METHODS
We investigate the prevalence of AFTN with normal TSH level.Between 01.01.2011 and 31.12.2018, 1505 nuclear scans were performed, in two groups.In the first group we performed 1220 thyroid scan with Tc-99m to investigate the behavior of 2000 nodules found on ultrasound. In the second group, of 285 patients with hyperparathyroidism a dual tracer scan with Sestamibi and Tc-99m was performed. We used the Pertechnetate scan to investigate the behavior of 90 incidentally found nodules on ultrasound. Results: RESULTS
On the first group we demonstrated AFNT in 30% of the cases. On the second group AFNT was found in 20/90 (22%). Conclusion: CONCLUSION
Thyroid scan using Tc-99m is able to pick up the AFNT especially in multinodular goiters. The Tc-99m used in the dual tracer technique is a successful method to evaluate the presence of AFNT. In patients with thyroid nodules and normal TSH level to avoid unnecessary FNAC, a thyroid scan must be performed, especially in regions with iodine deficiency. References: LITERATURESurvey on thyroid diseases in Cyprus 2005CANCER ARCHIVE(Urojod test 1997, thyrochem 2015). (ATA,ETA). guidelines

Is there a role for semiquantitative parameters to characterize incidental focal thyroid uptake on (18)F-FDG PET/CT study?
R. Durmo1, D. Albano1, M. Bonacina1, M. Gazzilli1, E. Cerudelli1, F. Dondi2, A. Mazzoletti2, P. Bellini2, F. Bertagna2, R. Giubbini2;
1Nuclear Medicine, Spedali Civili di Brescia, Brescia, ITALY, 2Nuclear Medicine, University of Brescia and Spedali Civili di Brescia, Brescia, ITALY.

Aim/Introduction: Thyroid incidental uptake (TIU) on fluorine-18 fluorodeoxyglucose PET/CT (FDG PET/CT) is defined as an uptake newly detected in patients who underwent imaging for non thyroid diseases. The clinical significance of TIU in FDG PET/CT studies remains controversial. The aim of this large retrospective study was to (a) establish the prevalence and pathological nature of focal TIU, (b) to establish possible metabolic PET parameters cut-off over which a malignant lesion should be suspected and (c) to assess a gender correlation of PET/CT parameters and malignancy. Materials and Methods: We retrospectively reviewed a total of 41169 patients who underwent a FDG PET/CT for non thyroid diseases between January 2012 and December 2018. A TIU was diagnosed in 695 (1.6%) patients (159 male; 536 female; average age 64). Of 695 TIU, 184 (26.4%) underwent further investigation to determine the nature of the uptake. We measured the maximum standardized uptake value body weight (SUVmax), SUVmean, lean body mass (SUVlbm), body surface area (SUVbsa), metabolic tumor volume (MTV), total lesion glycolysis (TLG) of TIU. Receiver operating curves (ROC) were calculated to determine optimal cut-off values between malignant and benign lesions. Moreover semiquantitative metabolic parameters between benign and malignant TIU were compare using T-test. Results: Fifty-seven (22 male, 35 female) of the 184 patients who underwent ultrasound guided fine-needle aspiration biopsy or thyroidectomy had malignant disease (31%), 98/184 (29 male; 63 female) were benign (53.3%) and 29/184 (8 male, 21 female) were indeterminate (15.7%) at cytological examination in absence of surgery. The ROC derived cut-off was SUVmax=7.27 (sensitivity=78.6, specificity=56.1, AUC=0.713), SUVmean=3.84 (sensitivity=74.5, specificity=54.4, AUC=0.663), SUVlbm=4.8 (sensitivity=77.3, specificity=63.2, AUC=0.719), SUVbsa=2.14 (sensitivity=82.3, specificity 56.1, AUC=0.79), MTV=1.5 (sensitivity=80.6, specificity 41.8, AUC=0.592) and TLG=8.6 (sensitivity=71.4, specificity 45.5, AUC=0.509). A statistical significant difference at T-test was observed between benign and malignant SUVmax, SUVmean, SUVlbm, SUVbsa (p<0.05).Metabolic tumor volume (MTV and TLG) were not significant different between malignant and benign lesion. There were not significant statistical difference in the semiquantitative parameters between female and male patients (p>0.05). Conclusion: There is a relatively high possibility of a malignant lesion in TIU. Semiquantitative parameters could be a useful tool in the assessment of TIU, however there are no safe and definitive cut-off values to discriminate between malignancy and benign lesion. References: none

Technetium-99m MIBI Scintigraphy Contribution In The Assessment Of Cold Thyroid Nodule
A. Chehboun1, D. Foudil1, Q. Naili1, M. Serir2, L. Bougrina3, L. Griene4, S. E. Bendib2, S. Mimouni-Zerguini1;
1Endocrinology Unit-Pierre and Marie Curie Center, Algiers, ALGERIA, 2Radiology Unit-Pierre and Marie Curie Center, Algiers, ALGERIA, 3Cytology Unit-Pierre and Marie Curie Center, Algiers, ALGERIA, 4Hormonology Unit-Pierre and Marie Curie Center, Algiers, ALGERIA.

Aim/Introduction: Thyroïde nodules are common in endocrine pathology. Relatively, thyroid cancer is less frequent, but affects the thyroid nodule management. The fine needle aspiration biopsy (FNAB) is the gold standard test. Nevertheless, Technetium-99m-MIBI scintigraphy represents a supplementary alternative in difficult cases. Objectives of the study: Evauate the diagnostic value of technetium-99m methoxyisobutylisonitrile (99mTC-MIBI) scintigraphy in the assessment of cold thyroid nodules. Materials and Methods: Prospective study of 203 operated patients with nodular goiter (NG). The total number of cold nodules on 99mTc-pertechnetate scans was 380, confirmed by ultrasonography and measured more than 10mm or equal. The thyroid scan was performed 15 min and 120 min after i.v. injection of 555 MBq of 99mTc-MIBI. 99mTC-MIBI uptake in the nodule compared with that in surrounding normal thyroid tissue was scored for both early and delayed images as follows: 0, cold; 1, decreased; 2, equal; 3, increased. Semi-quantitative analysis was performed using a lesion to non-lesion ratio on early (ER) and delayed images (DR). Additionally, a retention index (RI) was calculated using the formula RI= (DR-ER) x 100/ER. The malignancy criteria were a positive retention and increased uptake in the nodule in the early and delayed images. And these data was compared to histopathological results. Results: Histopathologically, the nodules were found to be well-differentiated cancer in 29 cases, medullary cancer in 3, poorly differentiated cancer in 5 and benign in 343 cases. None of the malignant nodules were cold on MIBI at the early and delayed images. An increased uptake in both early and delayed images was found in 24 malignant nodules (64.9%) from whom 18 (75%) with a positive retention index. A receiver operating characteristic analysis was performed to determine threshold value for the RI as 1.95 with an area under the curve (AUC) of 0.65. When nodules with increased uptake in both the early and delayed images and a positive retention index were considered as malignant, sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 0.49, 0.96, 0.56, 0.95 and 0.91. The highest sensitivity (0.95) was obtained at multivariate analysis by logistic regression, when both score 2+3 at only delayed images with a positive retention index were considered as malignant Conclusion: 99mTC-MIBI scintigraphy could be helpful in the preoperative assessment of thyroid nodules, particularly, those with non diagnostic or indeterminate cytology. References: none

Diagnostic performance of technetium-99m (99m Tc) methoxy-isobutyl-isonitrile (MIBI) for differentiation of malignant from benign thyroid nodules with indeterminate or non-diagnostic fine needle aspiration cytology (FNAC)
I. Iakovou, E. Giannoula, A. Kalaitzoglou, V. Mpalaris, K. Michailo, G. Arsos;
Academic Dpt Of Nuclear Medicine, Papageorgiou Hsp, Thessaloniki, GREECE.

Aim/Introduction: Thyroid nodules are common, their prevalence being largely dependent on the identification method ranging from 4-7% when identified by palpation to 20-75% when detecting by ultrasound techniques. FNAC is a part of the diagnostic algorithm to detect or exclude thyroid malignancy. However, there is a large range in the percentage of non-diagnostic and indeterminate FNACs raising the need for new molecular imaging techniques to further characterize thyroid nodules. Although, 99mTc-MIBI has been initially introduced for myocardial perfusion and parathyroid scintigraphy, it has also a role as a non specific radiopharmaceutical for tumor imaging and in particular for diferentiating malignant from benign lesions in patients with non-diagnostic and indeterminate FNACs of thyroid nodules. The objective of the current work is to evaluate the utility of 99mTc-MIBI thyroid scintigraphy in differentiating malignant from benign thyroid nodules with indeterminate or non-diagnostic cytology. Materials and Methods: We retrospectively evaluated 23 patients affected by thyroid nodules with either indeterminate (16, 69.5%), class III or IV according to the Bethesda system or non-diagnostic (7, 30.5%) cytology. Planar images of the thyroid were acquired 10 and 60 minutes after 99mTc-MIBI administration, early and late SPECT images were applied when needed and wash-out index (WOI) was used as a quantitative method to evaluate thyroid nodules. All patients underwent total/near total thyroidectomy and scintigraphic results were compared to histological findings. Results: Twelve out of 23 patients were diagnosed with differentiated thyroid cancer (DTC) (7 papillary TC and 5 follicular TC) and the remaining with benign adenomas. Malignant nodules were detected by WOI with a threshold of -19%. Therefore, overall sensitivity, specifcity, PPV and NPV were 100%, 63.4%, 66.6% and 100%, respectively. Conclusion: In conclusion, semiquantitative 99mTc-MIBI scintigraphy imaging analysis is a useful tool in differential diagnosis of thyroid nodules with non-diagnostic and indeterminate FNAC. References: Thyroid nodules with indeterminate cytology: molecular imaging with ⁹⁹mTc-methoxyisobutylisonitrile (MIBI) is more cost-effective than the Afirma gene expression classifier.Heinzel A, Müller D, Behrendt FF, Giovanella L, Mottaghy FM, Verburg FA.Eur J Nucl Med Mol Imaging. 2014 Aug;41(8):
Select item 23529672Diagnostic performance of (99m)Tc-MIBI scan in predicting the malignancy of thyroid nodules: a meta-analysis.Treglia G, Caldarella C, Saggiorato E, Ceriani L, Orlandi F, Salvatori M, Giovanella L.Endocrine. 2013 Aug;44(1):70-8.

Comparison of 18F-fluorocholine PET-CT to 11C-methionine PET-CT for the localisation of hyperfunctioning parathyroid tissue in primary hyperparathyroidism
C. Mathey, C. Keyzer, G. Van Simaeys, N. Trotta, S. Lacroix, B. Corvilain, S. Goldman, R. Moreno-Reyes;
Erasme hospital, Bruxelles, BELGIUM.

Aim/Introduction: To investigate the diagnostic performance of 18F-fluorocholine (FCH) PET/CT compared to 11C-methionine (MET) PET/CT in the localisation of hyperfunctioning parathyroid tissue in patients with primary hyperparathyroidism (pHTP) in case of negative or inconclusive 99mTc-sestaMIBI SPECT (MIBI) findings. Materials and Methods: Fifty-eight patients with biochemical evidence of pHTP and negative or inconclusive MIBI were referred for evaluation by MET and FCH-PET/CT for pre-surgical localisation of hyperfunctioning parathyroid tissue. The PET/CT results were classified into 3 categories (positive, inconclusive or negative) based on the nodular aspect of tracer uptake and the visualisation of corresponding nodules on the CT. The PET/CT results were confronted to the surgical and histopathological findings used as gold standard. Results: Fifty-three patients with a median serum calcium level of 2.67+/-0.17 mmol/L and PTH level of 72+/-78 ng/L were included for analysis. FCH PET/CT was positive in 39 patients (74%), inconclusive in 3 (6%) and negative in 11 (21%) compared to 30 (57%), 4 (7%) and 19 (36%) respectively for MET PET/CT. FCH localised 13 additional foci (10 positive and 3 inconclusive) compared to MET. Twenty-six patients (sex F/M ratio16/10) underwent surgery and 31 lesions were resected (22 adenomas, 6 hyperplasia, 2 cancers, and 1 normal gland). FCH PET/CT correctly localised 26 lesions in 24/26 (92%) patients compared to 21 lesions in 20/26 (77%) patients localised by MET PET/CT. Per patient-based sensitivity and PPV were 96% and 96% for FCH vs. 87% and 95% for MET. Per lesion-based sensitivity and PPV were respectively 84% and 93% for FCH vs. 70% and 91% for MET (p=0,0010). At the follow-up, twenty-one (81%) patients were considered cured after the surgery while 3 (12%) patients have a biological recurrence of hypercalcaemia. Conclusion: FCH was found significantly more sensitive than MET for lesion detection and localisation of hyperfunctioning parathyroid tissue in case of negative or inconclusive MIBI scan. References: none

Added Value Of Fluorocholine (FCH) PET/CT To sestaMIBI Scintigraphy/SPECT (Sc) And Ultrasonography (US) For Preoperatory Detection Of Hyperfuntionning Parathyroid (PT) Glands In Patients With Hyperparathyroidism (HPT) And Chronic Kidney Disease (CKD)
J. Talbot1, J. Zhang-Yin2, T. Delbot3, M. Tassart4, I. Anton2, S. Balogova2, F. Montravers2, P. Haymann5, S. Périé6, M. Gauthé2, S. Gaujoux7;
1Hopital Tenon, Paris, FRANCE, 2Hopital Tenon, Nuclear Medicine, Paris, FRANCE, 3Hopital Cochin, Nuclear Medicine, Paris, FRANCE, 4Hopital Tenon Radiology, Paris, FRANCE, 5Hopital Tenon, Explorations fonctionnelles, Paris, FRANCE, 6Hopital Tenon, ORL, Paris, FRANCE, 7Hopital Cochin, Endocrine Surgery, Paris, FRANCE.

Aim/Introduction: Since the publication in 2014 of our pilot study about 18F-fluorocholine (FCH)-PET/CT in hyperparathyroidism (HPT), evidence have been widely provided on its ability to detect parathyroid (PT) adenomas in case of primary HPT and non-conclusive sestaMIBI scintigraphy/SPECT (Sc) and ultrasonography (US). In contrast, there are few data on FCH PET/CT performance when HPT is associated with chronic kidney disease (CKD). Detection of PT hyperplasia predominant in this setting is limited with Sc. We determined the added value of FCH PET/CT in this context. Materials and Methods: HPT was diagnosed and parathyroidectomy planned in 74 CKD patients. Based on the results of on-site reading (OR) of Sc and US performed by specialists of PT imaging, the surgeon considered that the location of abnormal PTs was unclear and referred those patients to FCH PET/CT from 2012 until 2018. Masked reading (MR) of Sc and FCH PET/CT was also performed. The equivocal results of readings were considered negative. The standard-of-truth was histology after parathyroidectomy and follow-up to rule out recurrent HPT and consider non-resected PT as normal. Results: According to the selection criteria, ORs of Sc and US were both negative in 24 patients, discrepant in 17, only US-positive in 28, only Sc-positive in 5. The overall patient-based positivity-rate (PBPR) was 74% for FCH, 19% for Sc and 55% for US.60 patients (80%) underwent parathyroidectomy; histology of 109 resected glands was hyperplasia in 61, adenoma in 30 and normal in 18. According to OR, gland-based sensitivity was 71% for FCH, 20% for Sc, 44% for US and specificity 99%, 98% and 90%, respectively. Results of MR were sensitivity 77% for FCH, 16% for Sc; specificity 99% and 98%. When Sc and US were both negative, FCH had a PBPR of 63% a gland-based sensitivity of 62% (OR) 76% (MR) and a 100% specificity. When US was positive and Sc negative, gland-based sensitivity was 58% for US vs. 66% (OR) 79% (MR) for FCH. OR gland-based sensitivity according to the KDIGO categories G2, G3, G4-5 respectively, was 67%, 79%, 90% for FCH; 15%, 29%, 40% for Sc and 43%, 50%, 50% for US. Conclusion: FCH appeared effective for detecting abnormal PT in patients with HPT and CKD G2 to G5. When Sc and US were non-contributive or discrepant to detect abnormal PTs, FCH PET/CT showed added value, improving the positivity rate and the gland-based sensitivity compared with both Sc and US. References: none

Preoperatory 18F-fluorocholine PET/CT performed in patients undergoing hemodialysis locates hyperfunctioning parathyroid glands and may show brown tumours
J. T. Zhang-Yin1, S. Perie2, M. Gauthe1, I. Anton1, H. Fessi3, J. Haymann4, P. Ronco3, F. Montravers1, S. Balogova1, J. Talbot1;
1Service de Médecine Nucléaire, Hôpital Tenon, Paris, FRANCE, 2Service d'ORL, Hôpital Tenon, Paris, FRANCE, 3Service de Néphrologie hémodialyse, Hôpital Tenon, Paris, FRANCE, 4Service de l'Exploration rénale fonctionnelle, Hôpital Tenon, Paris, FRANCE.

Aim/Introduction: In patients undergoing hemodialysis (HD), nuclear functional imaging has the advantage to display and localize orthotopic and ectopic hyperfunctioning parathyroid glands (PT) prior to initial parathyroidectomy (PTX) and in case of post-surgical recurrence. In primary hyperparathyroidism (HPT), 18F-fluorocholine (FCH) PET/CT has shown superior performance compared to sestaMIBI scintigraphy or SPECT/CT. No data on its diagnostic performance are currently available in HPT of HD. Brown tumours (BT) are rare skeletal anomalies that occur in case of prolonged HPT. They result from increased osteoclastic activity, often related to chronic kidney failure. We also aimed to determine the ability of FCH PET/CT to detect BT in HPT of HD. Materials and Methods: We included in this retrospective study all HPT patients on HD referred to our center between 2013 and 2018. FCH PET/CT was acquired on the neck and the thorax; if bone lesions were visible on PET or on CT, a complementary whole-body acquisition was performed. Results: In 41 patients on HD (13 with kidney transplant), 50 FCH PET/CTs were performed (16 for recurrent HPT post-PTX). 36 patients were then (re)operated. Initial PTX in 25 patients found 72 abnormal PT of which 62 were FCH-positive (detection-rate DR=86%); reoperation in 11 patients found 11 abnormal PT all FCH-positive (DR=100%). In 6 patients, were also found multiple osteolytic lesions with substantially increased FCH uptake, among them, 3 had more than 5 osteolytic lesions. BT was diagnosed based on histology in 2 patients, in 1 patient on the post-PTX change of the bone lesions on CT from osteoclastic to osteoblastic scars, and on the typical aspect of BT on CT in the last 3 patients. Conclusion: In patients on hemodialysis with hyperparathyroidism, FCH PET/CT showed a high detection-rate for abnormal parathyroid glands, particularly in case of post-PTX recurrence. This complete success in case of recurrent hyperparathyroidism may be explained by the increased metabolism of the gland which was left alone after initial PTX. Furthermore, brown tumours showed a substantially increased uptake of FCH. In this context, brown tumours must be considered among the causes of osteolytic lesions with increased FCH uptake. Thus, FCH PET/CT represents a powerful “One-stop-shop” examination, since it appears to be very sensitive for preoperatory detection of the abnormal parathyroid glands, and since it can guide parathyroidectomy, the most effective option for correcting the metabolic trouble of the bone revealed by high FCH uptake and responsible for brown tumours. References: none

Contribution of dual time point F-18 fluorocholine PET/CT for challenging pre-operative parathyroid imaging in primary hyperparathyroidism
L. M. Vija1, E. Gabiache2, P. Pascal1, S. Kanoun2, L. Dierickx2, C. Renaud3, B. Jean3, B. Herbault-Barres4, S. Brillouet5, S. Grunenwald6, M. Vialon6, P. Caron6, F. Courbon2;
1Nuclear Medicine,Institut Universitaire de Cancerologie IUCTO, ICR, Toulouse, FRANCE, 2Nuclear Medicine, Institut Universitaire de Cancerologie IUCTO, ICR, Toulouse, FRANCE, 3Thoracic Surgery, University Hospital-CHU, Toulouse, FRANCE, 4Pathology, Institut Universitaire de Cancerologie IUCTO, ICR, Toulouse, FRANCE, 5Institut Universitaire de Cancerologie IUCTO, ICR, Toulouse, FRANCE, 6Endocrinology, University Hospital-CHU, Toulouse, FRANCE.

Aim/Introduction: When cervical ultrasound and Tc-99m MIBI scans are not informative, second-line imaging should be considered for preoperative localization of pathologic parathyroid glands. Dual time point F-18 fluorocholine PET/CT (FCH PET/CT) combines molecular (PET) and morphological (CT) information with uptake modifications within time, increasing sensitivity for parathyroid gland detection. However, the optimal time point for image acquisition for FCH PET/CT remains under debate. We evaluate image acquisition time point for the localization of pathologic parathyroid glands on FCH PET/CT as well as detection rates and sensitivities in patients with primary hyperparathyroidism
Materials and Methods: Patients with primary hyperparathyroidism explored with a dual time point FCH PET/CT (at 10 and 60 minutes post injection) and with post-operative histological parathyroid analysis have been prospectively included in the study. Early versus late acquisitions have been analyzed both on visual and semi-quantitative analysis.
Results: Thirty-seven patients (13 men, 24 women, mean age 51 years (20-80) with primary hyperparathyroidism [serum calcium 2.79 mmol/l (2.4-2.91), PTH levels 108.6 ng/L (57-190)] had dual time FCH PET/CT, 34 of them after a negative or discordant US/Tc-99m-sestaMIBI scans. On visual analysis, uptake of pathologic parathyroid glands was similar on early versus late FCH PET/CT in 27 patients, in 1 patient early image acquisition was more intense, whereas in 8 patients (22 %) uptake was better visible on late acquisition. There was a tendency on FCH uptake increase in pathologic parathyroid glands on late images (p = 0.24), with a significant increase of parathyroid to thyroid ratio on semi quantitative analysis (SUVmax lesion/ thyroid; p = 0.01). On a per-lesion analysis, FCH-PET/CT sensitivity, specificity, positive and negative predictive values were 86 %, 33 %, 96 % and 11 % respectively. On a per-patient analysis, Se, Sp, PPV, NPV were 82 %, 14 %, 86 % and 11 %. FCH-PET/CT imaging made to remove successfully pathologic glands in 34 patients (adenomas n = 31, hyperplasia n = 3), with a global cure rate of 92 % and cure rate related to FCH contribution of 65 %. Conclusion: With FCH-PET/CT in second line imaging of primary hyperparathyroid patients, most pathologic parathyroid glands are adequately visualized on early imaging; for several patients, parathyroid adenomas are better visualized on late time points. Therefore in pre-operative parathyroid characterization, FCH-PET/CT with dual time acquisition remains a useful option when first-line imaging and early time FCH PET/CT are not informative. References: None

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