Endocrinology application of molecular imaging: current role of PET/CT.

BACKGROUND: In recent years, nuclear medicine imaging methods have proven to be of paramount importance in a wide variety of diseases, particularly in oncology, where they are crucial for assessing the extent of disease when conventional methods fall short. Moreover, nuclear imaging modalities are able to better characterize lesions using target agents related to specific pathways (e.g. glucose metabolism, cellular proliferation, amino acid transport, lipid metabolism, specific receptor ligands). The clinical presentation of endocrine diseases encompasses a broad spectrum of sign and symptoms. Moreover, endocrine tumors show varying degrees of aggressiveness from well differentiated and indolent to highly aggressive cancers, respectively. RATIONALE: With the application of new medicinal radio-compounds and increasingly advanced tomographic imaging technology, the utility of Positron Emission Tomography/Computed Tomography (PET/CT) in the field of endocrine diseases is expanding. AIM: This review aims to analyze and summarize the primary indications of PET/CT, providing a practical approach for clinicians. A comprehensive literature search on PubMed was conducted to provide an updated overview of the available evidence regarding the use of PET/CT in endocrinology. Within this review, we will discuss the applications of PET/CT, compare different radiopharmaceuticals and highlight the uptake mechanism, excluding neuroendocrine carcinomas from discussion. CONCLUSIONS: PET/CT is a valuable tool in diagnosing and managing endocrine disorders due to its capacity to furnish both functional and anatomical information, facilitate early lesion detection, guide treatment decisions, and monitor treatment response. Its non-invasive nature and precision make it an integral component of modern endocrine healthcare. This review aims to provide physicians with a clear perspective on the role of PET/CT imaging, discussing its emerging opportunities and appropriateness of use in endocrinological diseases.

FNA indication according to ACR-TIRADS, EU-TIRADS and K-TIRADS in thyroid incidentalomas at 18F-FDG PET/CT.

OBJECTIVE: Focal thyroid incidentaloma (TI) occurs in a 2% of 18F-FDG PET/CT and about one-third of TIs is cancer. Due to the lack of evidence on the optimal management of TI, current guidelines suggest performing fine-needle aspiration cytology (FNA). The study aim was to evaluate the reliability of ACR-TIRADS, EU-TIRADS, and K-TIRADS in indicating FNA in TIs. DESIGN: We retrospectively reviewed 18F-FDG PET/CT TIs recorded during the period 2016-2019. Enrolled were TIs with histologic outcome and autonomous nodules. Cases with uncertain matching between 18F-FDG PET/CT, US/scintiscan and histology were excluded. RESULTS: Eighty TIs at 18F-FDG PET/CT (median size 17 mm, median SUVmax 7.85) were included; a 26.2% was cancer. The percentage of nodules classified as high risk according to ACR-TIRADS, EU-TIRADS, and K-TIRADS was 20%, 30%, and 29.8%, respectively. The cancer prevalence in high-risk class was 56.2%, 66.7%, and 65.2% in ACR-TIRADS, EU-TIRADS, and K-TIRADS, respectively. ACR-TIRADS had the lowest number of cases with FNA indication (48%) and the K-TIRADS, the highest one (75%). Evaluating the reliability of the three systems in indicating FNA, we found a 100% sensitivity and NPV for EU-TIRADS and K-TIRADS; while all the three systems showed poor specificity and PPV. CONCLUSION: All TIRADSs were reliable to stratify the risk of cancer in focal TI. Comparing their reliability in indicating FNA, we found a good performance of EU-TIRADS and K-TIRADS. Considering the high cancer percentage expected in this setting of patients, those TIRADS with higher propensity to indicate FNA should be preferred.

Alemtuzumab-induced thyroid events in multiple sclerosis: a systematic review and meta-analysis.

PURPOSE: Autoimmune thyroid events (ATEs) are common side effects after alemtuzumab (ALZ) therapy in patients with multiple sclerosis (MS). Our purpose was to reach more robust evidence on prevalence and outcome of the spectrum of alemtuzumab-induced autoimmune thyroid events in patients with multiple sclerosis. METHODS: PubMed and Scopus were systematically searched through July 2019. Studies dealing with patients without personal history of thyroid dysfunctions and affected by MS treated with ALZ and reporting ATEs were selected. Data on prevalence and outcome of ATEs were extracted. A proportion of meta-analysis with random-effects model was performed. RESULTS: Considering the overall pooled number of 1362 MS patients treated with ALZ (seven included studies), a 33% prevalence of newly diagnosed ATEs was recorded. Among all ATEs, Graves' disease (GD) was the most represented [63% of cases, 95% confidence interval (CI) 52-74%], followed by Hashimoto thyroiditis (15%, 95% CI 10-22%). Interestingly, GD showed a fluctuating course in 15% of cases (95% CI 8-25%). Of all GD, 12% (95% CI 2-42%) likely had spontaneous remission, 56% (95% CI 34-76%) required only antithyroid drugs, 22% (95% CI 13-32%) needed additional RAI, and 11% (95% CI 0.9-29%) underwent definitive surgery. CONCLUSION: Among different categories of ATEs, Graves' hyperthyroidism was the most common thyroid dysfunction, occurring in more than half of cases. Antithyroid drugs should represent the first-line treatment for ALZ-induced GD patients. However, alemtuzumab-induced GD could not be considered as having a more favourable outcome than conventional GD, given the substantial chance to encounter a fluctuating and unpredictable course.

Variations in radioiodine ablation: decision-making after total thyroidectomy.

BACKGROUND: The role of radioiodine treatment following total thyroidectomy for differentiated thyroid cancer is changing. The last major revision of the American Thyroid Association (ATA) Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer in 2015 changed treatment recommendations dramatically in comparison with the European Association of Nuclear Medicine (EANM) 2008 guidelines. We hypothesised that there is marked variability between the different treatment regimens used today. METHODS: We analysed decision-making in all Swiss hospitals offering radioiodine treatment to map current practice within the community and identify consensus and discrepancies. RESULTS AND CONCLUSION: We demonstrated that for low-risk DTC patients after thyroidectomy, some institutions offered only follow-up, while RIT with significant activities is recommended in others. For intermediate- and high-risk patients, radioiodine treatment is generally recommended. Dosing and treatment preparation (recombinant human thyroid stimulation hormone (rhTSH) vs. thyroid hormone withdrawal (THW)) vary significantly among centres.

18F-FDG-PET/CT Imaging in Advanced Glottic Cancer: A Tool for Clinical Decision in Comparison with Conventional Imaging.

This study assessed the role of 18F-FDG PET-CT (PET/CT) to detect the cartilage and paraglottic infiltration in advanced glottic cancer comparing the results with those of conventional imaging (CI) (contrast-enhanced computed tomography and/or magnetic resonance). In addition, we assessed the prognostic value of quantitative parameters, measured on baseline PET/CT, in terms of event-free survival (EFS) and overall survival (OS). We retrospectively analyzed 27 patients with glottic squamous cell carcinoma stage III and IVA, treated in our institute between 2010 and 2016, comparing PET/CT, performed for staging and radiotherapy planning, and CI findings. Cohen's K was used to compare concordance between PET/CT and CI. Imaging findings were correlated with endoscopic evaluation and histological reports (gold standard (GS)). All lesions shown by CI were also detected by PET/CT imaging, and in 5 cases, a better definition of local infiltration was achieved with PET/CT than CI (5 CT). Sensitivity, specificity, and accuracy of PET/CT and CT were 95%, 86%, and 93% and 70%, 86%, and 74% for, respectively. MRI showed sensitivity and specificity of 100%. One false-negative (FN) cases and 1 false-positive (FP) case were observed with PET/CT with no difference compared to MRI (10 cases). Six FN cases and 1 FP case were observed with CT. Cohen's K was 0.60 (PET vs. CI) and 0.80 (PET vs. GS). Patients were followed-up for at least 24 months to calculate EFS and OS. 13 local recurrence and 7 deaths were recorded. Among quantitative PET parameters, baseline MTV was the most powerful predictor of outcome. Our data suggest a reliable sensitivity and accuracy of PET/CT in the evaluation of local extension, proving a useful method for initial local staging in addition to the well-established role in lymph-node and distant sites assessment. Furthermore, pretreatment MTV provides better prognostic information than other PET/CT parameters.

Additional value of integrated 18F-choline PET/4D contrast-enhanced CT in the localization of hyperfunctioning parathyroid glands and correlation with molecular profile.

PURPOSE: The localization of hyperfunctioning parathyroid gland(s) (HPTG) in patients with primary hyperparathyroidism (PHPT) with negative or inconclusive first-line imaging is a significant challenge. This study aimed to evaluate the role of integrated 18F-choline PET/4D contrast-enhanced computed tomography (4DCeCT) in these patients, compare its detection rate and sensitivity with those of 18F-choline PET/CT and (4DCeCT), and analyse the association between choline metabolism and morphological, biochemical and molecular parameters of HPTG. METHODS: We prospectively enrolled 44 PHPT patients with negative or inconclusive first-line imaging. 18F-Choline PET/CT and 4DCeCT were performed at the same time, and integrated 18F-choline PET/4DCeCT images were obtained after coregistration. Experienced physicians examined the images. The SUVratio and degree of contrast enhancement were recorded for each positive finding. Histopathology, laboratory and multidisciplinary follow-up were used as the standard of reference. Both the detection rates and sensitivities of the three imaging modalities were calculated retrospectively. Immunohistochemistry was performed to evaluate the molecular profile of HPTGs. RESULTS: 18F-Choline PET/4DCeCT was positive in 32 of 44 patients with PHPT (detection rate 72.7%), and 31 of 31 surgically treated patients (sensitivity 100%). These results were significantly (p < 0.05) better than those of 18F-choline PET/CT (56.8% and 80%, respectively) and those of 4DCeCT (54.5 and 74%, respectively). A significant correlation between SUV and calcium level was found. In a multivariate analysis, only calcium level was significantly associated with 18F-choline PET/4DCeCT findings. SUVratio and Ki67 expression were significantly correlated. CONCLUSION: Integrated 18F-choline PET/4DCeCT should be considered as an effective tool to detect PHPT in patients with negative or inconclusive first-line imaging. Choline metabolism is correlated with both calcium level and Ki67 expression in HPTG.

Endocrine and metabolic adverse effects of immune checkpoint inhibitors: an overview (what endocrinologists should know).

Immune checkpoint inhibitors (ICIs) are novel anticancer agents, recently introduced with the aim of boosting the immune response against tumors. ICIs are monoclonal autoantibodies that specifically target inhibitory receptors on T cells: cytotoxic T lymphocyte antigen 4 (CTLA4), programmed death 1 (PD-1) and its ligand (PD-1L). ICIs also generate peculiar dysimmune toxicities, called immune-related adverse events (irAEs), that can potentially affect any tissue, and some may be life-threatening if not promptly recognized. The endocrine and metabolic side effects of ICIs are reviewed here, with a particular focus on their clinical presentation and management. They are among the most frequent toxicities (around 10%) and include hypophysitis, thyroid disorders, adrenalitis, and diabetes mellitus. Treatment is based on the replacement of specific hormone deficits, accompanied by immunosuppression (with corticosteroids or other drugs), depending on irAEs grade, often without the need of ICI withdrawal, except in more severe forms. Prompt recognition of endocrine and metabolic irAEs and adequate treatment allow the patients to continue a therapy they are benefiting from. Endocrinologists, as an integral part of the multidisciplinary oncologic team, need to be familiar with the unique toxicity profile of these anticancer agents. Practical recommendations for their management are proposed.

Caso inusual de tumor de origen desconocido detectado con 18F-FDG PET/TC: carcinoma de células claras de la glándula tiroides metastásico / Unusual case of tumor of unknown origin found by 18F-FDG PET/CT: Metastatic clear cell carcinoma of the thyroid gland

No disponible

Multicentre clinical evaluation of the new highly sensitive Elecsys® thyroglobulin II assay in patients with differentiated thyroid carcinoma.

OBJECTIVE: A highly sensitive thyroglobulin assay (Elecsys® Tg II, Roche Diagnostics, Penzberg, Germany) has become available for monitoring patients with differentiated thyroid cancer (DTC). Here, we evaluated the clinical performance of Elecsys® Tg II assay in a multicentre patients series and compare it with the established Access® Tg assay (Beckman Coulter, Brea, CA, USA). DESIGN: Retrospective analysis on prospectively selected patients in four thyroid cancer referral centres with uniform DTC management. PARTICIPANTS: All DTC cases diagnosed, treated and followed up in four tertiary referral centres for thyroid cancer since January 2005 (n = 1456) were retrieved, and predefined selection criteria were applied to prevent relevant enrolment biases. A series of 204 patients was finally selected for this study. MEASUREMENTS: Samples had been stored at -80°C. Tg was measured by fully automated immunometric Elecsys® Tg II and Access® Tg assays in a centralized laboratory. RESULTS: Two hundred and four DTC were finally included. Of these, 10.8% had structural recurrence (sREC), and 81.4% showed no evidence of disease (NED) at the end of follow-up. There was a significant analytical bias between methods that cannot be used interchangeably. Using ROC curve analysis, the best basal and rhTSH-stimulated Tg cut-offs to detect sREC were 0.41 µg/L and 1.82 µg/L for Elecsys® and 0.36 µg/L and 1.62 µg/L for Access® assay, respectively. Using Cox proportional hazard regression, Tg was the only independent predictor of cancer relapse. CONCLUSIONS: Using appropriate assay-specific cut-offs, the clinical performance of the Elecsys® Tg II assay was comparable to that provided by the well-established Access® Tg assay.

Role of serum cytokeratin 19 fragment (Cyfra 21.1) as a prognostic biomarker in patients with differentiated thyroid cancer.

Differentiated thyroid cancers (DTC) account for up to 85% of thyroid cancers and generally display an excellent prognosis. However, in a minority of cases, DTC progress toward less differentiated phenotypes leading to distant metastases and even disease-related deaths. Circulating biomarkers are warranted to complement the gold standard DTC marker thyroglobulin (Tg) in identifying and monitoring such cases. We measured serum Tg and Cyfra 21.1 6 to 12 months after primary treatment in 473 DTC patients. A complete response of Tg was related to an excellent outcome in all cases. Among patients with incomplete Tg response Cyfra 21.1 levels <2.07 ng/mL were associated to favorable outcome while higher levels greatly increased the risk of disease related recurrences and deaths. Both markers retained independent prognostic values in multivariate analysis. In conclusion, Cyfra 21.1 is a tool available to independently predict survival of DTC patients not achieving excellent response after primary treatment.

Differentiating malignant from benign thyroid nodules with indeterminate cytology by 99mTc-MIBI scan: a new quantitative method for improving diagnostic accuracy.

Quantitative 99mTc-MIBI thyroid scintigraphy is a useful tool in differentiating malignant from benign thyroid nodules with indeterminate cytology. The aim of our report is to compare the diagnostic performance of different quantitative methods. We prospectively evaluated 20 patients affected by a thyroid nodule with a cytological diagnosis of class III or IV according to the Bethesda system. Planar images of the thyroid were acquired 10 and 60 minutes after 99mTc-MIBI administration and two different quantitative methods applied (i.e. wash-out index, WOind; retention index, R.I.). All patients underwent lobectomy or thyroidectomy and final histological findings were matched with MIBI results obtained with both quantitative methods. Four out of 20 patients had a final histological result of differentiated thyroid cancer, while benign findings were found in the remaining cases. Overall sensitivity, specificity, accuracy, PPV and NPV were 100% in all for the WOind and 100%, 57.1%, 62.5%, 25% for the R.I., respectively. In conclusion 99mTc-semiquantitative MIBI thyroid scintigraphy with WOind calculation is highly accurate in differential diagnosis of nodules with indeterminate cytology reading.

High-sensitive basal serum thyroglobulin 6-12 months after thyroid ablation is strongly associated with early response to therapy and event-free survival in patients with low-to-intermediate risk differentiated thyroid carcinomas.

OBJECTIVE: High-sensitive thyroglobulin assays (hsTg) has decreased the need for stimulated Tg measurements in patients with differentiated thyroid carcinoma (DTC). However, multiple assays analyzing the same samples may report different values. Accordingly, appropriate assay-specific cut-off levels should be selected in representative patient series. Here, we evaluate the role of a new hsTg assay in low-to-intermediate risk DTC patients and select appropriate assay-specific clinical cut-off limits. DESIGN: This was a retrospective study. The response to treatment was assessed according to ATA. METHODS: Patients with low-to-intermediate risk DTC treated and regularly followed-up in our thyroid center. Tg was measured on the Kryptor Compact Plus Instrument (BRAHMS Thermo Fisher Scientific). RESULTS: The study series comprised 201 DTC patients and excellent response (ER) was demonstrated in 184 (91.5%). Optimized threshold of basal Tg (onT4-Tg) measured 6-12 months after initial treatment was set by ROC curves analysis at 0.28 ng/mL. Having onT4-Tg <0.28 ng/mL at 6-12 months after treatment was associated with longer disease-free survival of Kaplan-Meier (P < 0.001), ER at early follow-up (odds ratio (OR): 165, P < 0.001) and absence of relapse during follow-up (OR: 328, P = 0.0001). CONCLUSIONS: Patients with low- and intermediate-risk DTC could be considered cured when they have onT4-Tg levels <0.28 ng/mL coupled with negative imaging at their first post-ablation visit.

Detecting N-RAS Q61R Mutated Thyroid Neoplasias by Immunohistochemistry.

Recently, the immunohistochemistry (IHC) for N-RAS Q61R has been developed and commercialized for clinical practice. Here, we investigated the reliability of IHC to identify N-RAS Q61R mutated thyroid neoplasia. A series of 24 consecutive thyroid lesions undergone surgery following indeterminate cytology were enrolled. Paraffin sections were stained for IHC using the rabbit monoclonal anti-human N-RAS Q61R, clone SP174. N-RAS mutations in codon 61 were also investigated by automated sequencing. At histology, 12 cases of follicular carcinoma, cytologically defined as follicular lesions, 1 papillary cancer, 7 follicular adenomas, and 4 hyperplastic nodules were found. Of these, 4 showed a positive IHC for anti N-RAS antibody where N-RAS expression was detected mainly at cytoplasmic level with similar intensity of reaction. The remaining cases had negative IHC. A 100% concordance between IHC and molecular analysis for N-RAS Q61R was observed. In conclusion, this study shows high reliability of IHC to identify N-RAS Q61R mutated thyroid lesions with high cost-effectiveness. These data indicate the reliability of IHC to identify N-RAS Q61R mutated thyroid neoplasia and suggest to adopt this approach for a more accurate management of patients, when indicated.

Multimodal imaging in an unusual case of radionecrosis of the pubic symphysis / Imágenes multimodales en un caso inusual de radionecrosis de la sínfisis púbica

No disponible

Thyroid nodules with indeterminate cytology: prospective comparison between 18F-FDG-PET/CT, multiparametric neck ultrasonography, 99mTc-MIBI scintigraphy and histology.

PURPOSE: To evaluate the role of (18)F-flurodeoxiglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) in predicting malignancy of thyroid nodules with indeterminate cytology. PATIENTS AND METHODS: We analysed 87 patients who have been scheduled to undergo surgery for thyroid nodule with indeterminate cytology. All patients underwent (18)F-FDG-PET/CT, multiparametric neck ultrasonography (MPUS), and (99m)Tc-methoxyisobutylisonitrile scintigraphy ((99m)Tc-MIBI-scan). Histopathology was the standard of reference. We compared the sensitivity (SE), specificity (SP), accuracy (AC), positive (PPV) and negative predictive (NPV) values of (18)F-FDG-PET/CT with those of (99m)Tc-MIBI-scan and MPUS in detecting cancer. Univariate and multivariate analyses evaluated the association between each diagnostic tool and histopathology. RESULTS: On histopathology, 69 out of 87 nodules were found to be benign and 18 to be malignant. The SE, SP, AC, PPV and NPV of (18)F-FDG-PET/CT were 94, 58, 66, 37 and 98% respectively. The SE, AC and NPV of (18)F-FDG-PET/CT were significantly higher than those of MPUS and (99m)Tc-MIBI-scan. The association of both positive (18)F-FDG-PET/CT and MPUS (FDG+/MPUS+) showed significantly lower SE (61% vs 94%) and NPV (88% vs 98%) than (18)F-FDG-PET/CT alone, but significantly higher SP (77% vs 58%). On univariate analysis, (18)F-FDG-PET/CT and the combination of FDG+/MPUS+ and of FDG+/MIBI- were all significantly associated with histopathology. On multivariate analysis, only FDG+/MIBI- was significantly associated with histopathology. CONCLUSION: The AC of (18)F-FDG-PET /CT in detecting thyroid malignancy is higher than that of (99m)Tc-MIBI-scan and MPUS. A negative (18)F-FDG-PET/CT correctly predicts benign findings on histopathology. The association of FDG+/MPS+ is significantly more specific than (18)F-FDG-PET/CT alone in identifying differentiated thyroid cancer. A positive (18)F-FDG-PET/CT is significantly associated with malignancy when qualitative (99m)Tc-MIBI-scan is rated as negative.

Pancreatic atypical mycobacteriosis evaluated by 18F-FDG-PET/CT / Micobacteriosis atípica pancreática evaluada con 18F-FDG PET/TC

No disponible

DIAGNOSIS OF ENDOCRINE DISEASE: High-yield thyroid fine-needle aspiration cytology: an update focused on ancillary techniques improving its accuracy.

Thyroid fine-needle aspiration (FNA) cytology is a fast growing field. One of the most developing areas is represented by molecular tests applied to cytological material. Patients that could benefit the most from these tests are those that have been diagnosed as 'indeterminate' on FNA. They could be better stratified in terms of malignancy risk and thus oriented with more confidence to the appropriate management. Taking in to consideration the need to improve and keep high the yield of thyroid FNA, professionals from various fields (i.e. molecular biologists, endocrinologists, nuclear medicine physicians and radiologists) are refining and fine-tuning their diagnostic instruments. In particular, all these developments aim at increasing the negative predictive value of FNA to improve the selection of patients for diagnostic surgery. These advances involve terminology, the application of next-generation sequencing to thyroid FNA, the use of immunocyto- and histo-chemistry, the development of new sampling techniques and the increasing use of nuclear medicine as well as molecular imaging in the management of patients with a thyroid nodule. Herein, we review the recent advances in thyroid FNA cytology that could be of interest to the 'thyroid-care' community, with particular focus on the indeterminate diagnostic category.