Thyroid Uptake Research Articles

Hürthle Cells on Fine-Needle Aspiration Cytology Are Important for Risk Assessment of Focally PET/CT FDG Avid Thyroid Nodules.

Simple SummaryPET/CT fluorodeoxyglucose (FDG) scans are routinely used in patients to detect signs of malignant tumours or evidence of inflammation in the body. A total of 1–2% of patients show focal thyroid gland FDG uptake and 35–40% are malignant. FDG also detects metabolically active lesions containing mitochondria, known as Hürthle cells. Over 3 years, 47 patients in one hospital were found to have focal thyroid gland uptake. A total of 18 (38.2%) of the patients had malignancy, 15 (31.9%) had benign lesions that contained Hürthle cells and 14 (29.8%) had focally increased thyroid gland FDG PET/CT uptake with no cause identified. Exclusion of the Hürthle cell patients increased the risk of malignancy of the remaining PET-positive nodules from 38% to 68%. It is important to recognize Hürthle cells on FNA cytology in FDG PET/CT-positive nodules as this affects the risk of malignancy and the clinical management of focally FDG PET/CT-positive nodules.This study assesses the role of [18F] FDG PET/CT, fine needle aspiration (FNA) cytology and ultrasound in the 1–2% of patients with focally positive thyroid nodules on FDG PET/CT. All FDG PET/CT scans with focally increased thyroid FDG PET/CT uptake performed over 37 months in one institution were matched to patients undergoing thyroid FNA. Diffuse FDG PET/CT uptake patients were excluded. A total of 47 patients showed focally increased thyroid uptake. Consistent with previous studies, 18 (38.2%) patients had malignancy—12 primary thyroid carcinoma, 1 parathyroid carcinoma, 3 metastatic carcinoma to the thyroid and 2 lymphoma. A total of 15 (31.9%) lesions categorized as non-malignant contained Hürthle cells/oncocytes. A total of 14 lesions (29.8%) had focally increased FDG PET/CT uptake with no specific cytological or histopathological cause identified. No focally PET avid Hürthle cell/oncocytic lesions were found to be malignant. Exclusion of oncocytic lesions increased the calculated risk of malignancy (ROM) of focally PET avid nodules from 38% to 68%. It may be useful to exclude focally FDG PET/CT avid Hürthle cell/oncocytic lesions, typically reported as follicular neoplasm or suspicious for a follicular neoplasm, Hürthle cell type (Oncocytic) type, RCPath Thy 3F: Bethesda IV or sometimes Thy 3a: Bethesda III FNAs) from ROM calculations. Oncocytic focally PET/CT FDG avid lesions appear of comparatively lower risk of malignancy and require investigation or operation but these lesions should be readily identified by FNA cytology on diagnostic work up of focally PET avid thyroid nodules.

Prevalence of incidental thyroid malignancy on routine 18F-fluorodeoxyglucose PET-CT in a large teaching hospital

PurposeTo quantify incidental thyroid pathology including malignancy on routine 18F-FDG PET-CT scansTo compare standardised uptake values (SUVmax) in thyroid malignancy subtypesMethods and materialsThis is a retrospective study of all 18F-FDG PET-CT scans (n = 6179) performed in a teaching hospital between June 2010 and May 2019. RIS database search of reports for the word “thyroid” was performed. Studies with evidence of thyroid uptake were included. Patient age and gender, primary indication for PET scan (malignant or non-malignant), thyroid result on PET (diffuse or focal tracer uptake, SUVmax), ultrasound and FNAC results were recorded.ResultsIncidental abnormal thyroid tracer uptake as a proportion of all 18F-FDG PET-CT scans was 4.37% (n = 270). Out of region patients (n = 87) whose records could not be obtained were excluded leaving a study group of n = 183. Ninety-four in this group had focal uptake, and 89 had diffuse uptake. Fifty-five patients in the focal group had undergone further investigations. Of these, 30 were thought to be benign on USS alone, and 25 patients underwent USS/FNAC. Thirteen (24%) malignancies were identified (5 papillary, 6 follicular, 1 poorly differentiated thyroid cancer, 1 metastatic malignancy). Mean SUVmax for papillary carcinoma was noted to be 8.2 g/ml, and follicular carcinoma was 12.6 g/ml.ConclusionIncidental abnormal thyroid 18F-FDG PET-CT uptake in PET-CT scans of 4.37% is in keeping with the known limited literature. Rather similar number of patients was noted in the focal and diffuse tracer uptake categories in the final study group. Around quarter of the focal lesions were identified to be malignant, implying focal lesions should always be further investigated.

Efficacy and safety of Xiaochaihu decoction for subacute thyroiditis: A protocol of systematic review and meta-analysis.

Background:Subacute thyroiditis (SAT) is a transient and self-limiting inflammatory thyroid disease. There is no clear evidence for specific etiology, but it is generally thought to occur after viral infection. Characteristics of SAT include severe pain of the anterior neck, enlarged firm thyroid, disordered thyroid function, elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), typical ultrasound findings (hypoechoic areas) and low thyroid uptake of radioactive iodine or technetium-99 m because of the destructive etiology of the hyperthyroidism. Evidences showed Xiaochaihu decoction (XCHD) has a significant effect on improving the symptoms of SAT patients. The purpose of this study is to assess the safety and effectiveness of XCHD for patients with SAT.Methods and analysis:The literature that has been identified via searching 6 Chinese electronic databases and eight English electronic databases from inception to September 21, 2020 will be included in the study. Research selection, data extraction as well as research quality assessment will be completed by 2 experienced researchers independently. The primary outcome is remission rate. Data analysis will be conducted by the RevMan 5 software, and GRADE will help to assess the level of evidence. The heterogeneity of data will be investigated by a heterogeneity x2 test, as well as the Higgins I2 test. A subgroup analyses and sensitivity analysis will be conducted to explore the sources of heterogeneity.Results:The results of this study will be published in a peer-reviewed journal.Conclusion:This study will draw a conclusion about whether XCHD is safe and effective in treating SAT on the basis of evidence-based medicine. This conclusion will provide areliable scientific evidence for the alternative treatment for the management of SAT.OSF registration number:https://osf.io/8hbue.

A prospective comparative study of two methods for the individual calculation of 131I activity in the treatment of hyperthyroidism

ObjectiveRadioiodine (131I) is an established modality of definitive treatment of hyperthyroidism. In spite of the vast experience available, there are still several aspects to be clarified, such as whether fixed or calculated doses should be used. The aim of this study was to assess whether efficacy of this treatment could be improved by implementing a simple dosimetric calculation method including ultrasonographic estimation of thyroid volume and a single measurement of 24-h 131I thyroid uptake. MethodsA prospective non-inferiority study was designed to compare two procedures to calculate radioiodine activity: the “semi-fixed” dose method (A), and the “calculated” dose method (B). The first consisted of activity escalation (185MBq steps) based on etiology of hyperthyroidism, 131I uptake, and treatment objective. The second method was based on the “dosimetric compromise” concept, considering 24-h uptake and thyroid volume as the only factors and using a standard half-life of 5.5 days. The target absorbed dose was 150Gy, but after a preliminary analysis (first 100 cases) it was increased to 200Gy in diffuse toxic goiters (DTGs). ResultsA total of 212 patients were included. Method B was at least as effective in terms of final and functional outcome, with a trend to more success and less hypothyroidism. In addition, activities administered were significantly lower. ConclusionIn radioiodine therapy of hyperthyroidism, a simple dosimetric method that provided results at least equal to those of a fixed dose-based method, with lower administered activities, could be implemented.

Increased Risk of Radioiodine Treatment Failure Associated with Graves Disease Refractory to Methimazole

Objective: Iodine 131 (I-131) radioactive iodine (RAI) therapy has been the preferred treatment for Graves disease in the United States; however, trends show a shift toward antithyroid drug (ATD) therapy as first-line therapy. Consequently, this would favor RAI as second-line therapy, presumably for ATD refractory disease. Outcomes of RAI treatment after first-line ATD therapy are unclear. The purpose of this study was to investigate treatment failure rates and potential risk factors for treatment failure, including ATD use prior to RAI treatment.Methods: A retrospective case control study of Graves disease patients (n = 200) after I-131 RAI therapy was conducted. Treatment failure was defined as recurrence or persistence of hyperthyroidism in the follow-up time after therapy (mean 2.3 years). Multivariable regression models were used to evaluate potential risk factors associated with treatment failure.Results: RAI treatment failure rate was 16.5%. A majority of patients (70.5%) used ATD prior to RAI therapy, predominantly methimazole (MMI) (91.9%), and approximately two-thirds of patients used MMI for >3 months prior to RAI therapy. Use of ATD prior to RAI therapy (P = .003) and higher 6-hour I-123 thyroid uptake prior to I-131 RAI therapy (P<.001) were associated with treatment failure. MMI use >3 months was also associated with treatment failure (P = .002).Conclusion: More patients may be presenting for RAI therapy after failing first-line ATD therapy. MMI use >3 months was associated with RAI treatment failure. Further studies are needed to investigate the association between long-term first-line ATD use and RAI treatment failure.

Least Significant Changes and Reproducibility of 131I Uptake Test.

Radioactive iodine uptake (RAIU) is one of the important tests performed in the departments of nuclear medicine, testing thyroid function by measuring the amount of 131I uptake after oral administration. A RAIU value measured 4 and 24 h after administration has been widely used for differential diagnosis of thyroid function and for the calculation of treatment dose. This study was performed to define practical methods for reproducibility and least significant change (LSC) values replicating thyroid measurements. In the study were 119 patients referred to the nuclear medicine department for examination of thyroid gland function with the diagnosis of Graves' disease (60), toxic multinodular goiter (29), thyroiditis (10), thyroid cancer (6), and unknown etiology (14). The level of thyroid stimulating hormone (TSH) among the patients was 2.07 ± 6.74 μIU mL-1. RAIU measurements were carried out by two different technicians, who have performed an equal number of measurements from each diagnosis in reference to the clinical diagnosis. Measurement of each patient was performed twice at 4 and 24 h after the administration under stable geometry and counting conditions using a standard procedure. Data were evaluated using statistical methods. For assessment of the reproducibility, three parameters were used: reproducibility coefficient (RC), the root-mean-square standard deviation (SDRMS), and the least significant change values. The average RAIU values of the first and second measurements were found as 23.71 ± 16.52% and 23.94 ± 16.64% at 4 h (p >0.05), and 35.33 ± 19.22% and 35.49 ± 19.19% at 24 h (p >0.05), respectively. For thyroid uptake values repeated at 4 and 24 h after radioiodine administration, the mean difference was found to be -0.24 ± 0.62% [limits of agreement (%); -1.44 to 0.97] at 4 h and -0.16 ± 0.44% [limits of agreement (%); -1.02 to 0.70] at 24 h. Confidence intervals were within the limits of agreement (d̅-1.96 SD and d̅+1.96 SD). When the correlation between the repeated RAIU measurements was examined taking the differences and averages into account, there was a negative correlation between 4-h measurement pairs (r=-0.203, p <0.05). On the other hand, a significant correlation was not found between the 24-h measurement pairs (r=0.074, p >0.05). RC, SDRMS, and LSC were calculated as 0.70%, 0.46%, and 1.29% for the 4 h measurements and 0.54%, 0.33%, and 0.91% for the 24-h measurements, respectively. Although there was a minor difference between measurement pairs at 4 and 24 h post-administration, the difference appeared to be insignificant without an apparent effect in the clinical settings.

Quantification of the Thyroid Scan (TS) and correlation to Multiparametric Ultrasounds (MPUS): A textbook case of nuclear molecular imaging

For decades, thyroid scintigraphy (TS) has been considered an interesting tool, especially in the field of hyperthyroidism. In recent years, TS has rapidly gained importance since it provides unique molecular information that cannot be obtained by any other modality. In fact, despite a limited 6mm spatial resolution, it can highlight molecular and histo-functional changes that characterize most thyroid function disorders. However, to become such a powerful molecular image, the TS must be quantified. How much iodine is taken-up characterizes the Uptake (Up), while where iodine distributes characterizes the Spatial Targeting (ST). Methodology, results and limits of the thyroid Uptake are presented, including suppressed tests. Methods to determine the anatomical thyroid volume are revisited with special focus on planar scintigraphy. Recent developments in quantification make the 123I-TS a new molecular imaging procedure. Since 123I targets the sodium iodide symporter (NIS) and tracks the whole organification process, we derived a fundamental linear relationship between the TSH and the precocious (120–240min) Uptake (p123IUp). This relationship indicates whether the 123I input follows the physiological TSH stimulation or is predictive of a non TSH-suppressible function, whatever the imaging pattern. This allows identification of toxic or compensated (TSH>0.1mU/L) Thyroid Functional Autonomy (TFA), even at baseline. Spatial Targeting, measured with the aid of computational algorithms, provides a reproducible Spatial Targeting Index (STI). This allows estimating a functional thyroid volume, that is likely more informative than the anatomical one. Most aspects of TS quantification and the interest to compare the structure (mostly MultiParametric US) and the function (molecular 123I-TS) are presented.

Prevalence and Treatment Outcomes of Marine-Lenhart Syndrome in Japan

Introduction: Marine-Lenhart syndrome (MLS) is now understood to be a combination of Graves’ disease and autonomously functioning thyroid nodule(s) (AFTNs). The prevalence of the syndrome and suitable treatments for those living in iodine-sufficient areas are uncertain. Objectives: We aimed to investigate the prevalence, treatment, and prognosis of MLS in Japan, an iodine-sufficient area. Methods: This study involved patients who visited our hospital between February 2005 and August 2019. Among patients with both thyrotoxicosis and thyroid nodule(s) larger than 10 mm, MLS and isolated AFTNs were diagnosed based on serum thyroid-stimulating hormone receptor antibody levels and scintigraphy using radioiodine or technetium-99m and thyroid uptake. Results: Twenty-two patients were found to have MLS, compared to 372 with isolated AFTNs and 8,343 with Graves’ disease, during the period. Therefore, the rate of MLS cases was 0.26% among all patients with Graves’ disease (22/8,343). Treatments and outcomes were assessed for cases of MLS (n = 18) and isolated AFTNs (n = 269). Antithyroid drugs (ATDs) were withdrawn in 27.8% of cases in the MLS group and 10.3% in the isolated AFTN group. There was no significant difference in the clinical outcome after ATD withdrawal between the 2 groups. However, the rate of hypothyroidism after radioactive iodine (RAI) administration was significantly higher in the MLS group than in the isolated AFTN group (42.9 vs. 9.0%, p = 0.005) despite similar doses of RAI. Conclusions: The prevalence of MLS among patients with Graves’ disease was 0.26% in Japan. RAI therapy induces hypothyroidism more frequently than in those with AFTNs probably because RAI is taken up in the surrounding Graves’ tissues.

Uncertainty quantification of bioassay functions for the internal dosimetry of radioiodine.

Bioassay functions, which are provided by the International Commission on Radiological Protection, are used to estimate the intake activity of radionuclides; however, they include considerable uncertainties in terms of the internal dosimetry for a particular individual. During a practical internal dose assessment, the uncertainty in the bioassay function is generally not introduced because of the difficulty in quantification. Therefore, to clarify the existence of uncertainty in the bioassay function and provide dosimetrists with an insight into this uncertainty, this study attempted to quantify the uncertainty in the thyroid retention function used for radioiodine exposure. The uncertainty was quantified using a probabilistic estimation of the thyroid retention function through the propagation of the distribution of biokinetic parameters by the Monte Carlo simulation technique. The uncertainties in the thyroid retention function, expressed in terms of the scattering factor, were in the ranges of 1.55–1.60 and 1.40–1.50 for within 24 h and after 24 h, respectively. In addition, the thyroid retention function within 24 h was compared with actual measurement data to confirm the uncertainty due to the use of first-order kinetics in the biokinetic model calculation. Significantly higher thyroid uptakes (by a factor of 1.9) were observed in the actual measurements. This study indicates that consideration of the uncertainty in the thyroid retention function can avoid a significant over- and under-estimation of the internal dose, particularly when a high dose is predicted.

Increased thyroid uptake on 18F-FDG PET/CT is associated with the development of permanent hypothyroidism in stage IV melanoma patients treated with anti-PD-1 antibodies.

To determine performances of 2-deoxy-2-(18F)fluoro-D-glucose (18F-FDG) positron emission tomography (PET) to detect the development of permanent thyroid dysfunction (PTD), and to evaluate the prognostic value of early increased thyroid uptake in stage IV melanoma patients treated with anti-programmed death 1 (anti-PD-1) antibodies. Twenty-nine patients were retrospectively enrolled. PTD was defined as symptomatic thyroid disorder requiring long-term specific treatment. On the first PET performed during follow-up, maximal standardized uptake value of the thyroid (SUVmax-Th) and SUVmax-Th/SUVmax-blood-pool ratio (Th/B) were measured. Areas under ROC curves (AUC) of these parameters for the diagnostic of PTD were compared. Cutoff values were defined to maximize the Youden's index. Survival analyses were performed according to the Kaplan-Meier method and compared using the log-rank method between patients with and without enhanced thyroid uptake according to cutoff values defined with the Hothorn and Lausen method. Four patients presented PTD. Median SUVmax-Th and Th/B were, respectively, 2.11 and 1.00. The median follow-up period was 21.7months. AUC were 1.0 (CI95% 0.88-1.0) for both parameters. Optimal cutoff values were, respectively, SUVmax-Th > 4.1 and Th/B > 2.0, both conferring sensitivities of 100% (CI95% 40-100%) and specificities of 100% (CI95% 86-100%). The median progression-free survival and overall survival were 11.3months and 33.5months, respectively. Using optimized cutoffs, there was no statistically significant difference of survival. SUVmax-Th > 4.1 and Th/B > 2.0 provided perfect diagnostic performances to detect patients that developed PTD. No significant survival difference was found between patients with and without increased thyroid uptake.

Serum thyroid stimulating hormone level for predicting utility of thyroid uptake and scan

ABSTRACT Background Thyroid uptake and scan (TUS) is a clinical tool used for differentiation of thyrotoxicosis etiologies. Although guidelines recommend ordering a TUS for evaluation of low TSH levels, no specific value is defined. This study aimed to determine a TSH cutoff at which TUSs yield a greater likelihood of successful determination of etiology to avoid unnecessary testing. Methods This was a retrospective study on 137 patients seen by an endocrinologist who underwent TUS for evaluation of low TSH (<0.4 μU/mL). A receiver operating curve analysis was performed to determine the TSH cutoff with maximal sensitivity and specificity for prediction of diagnostic utility. Results Ninety percent of TUSs (n = 123) led to a diagnosis, while 10% (n = 14) were inconclusive or normal. Diagnoses included Graves’ diseases (52%), toxic multinodular goiter (19%), thyroiditis (12%), and solitary toxic adenoma (7%). The median TSH value was 0.008 μU/mL (IQR 0.005, 0.011), and the median free T4 value was 1.7 μU/mL (IQR 1.3, 2.8). The ROC analysis produced an area under the curve of 0.86. The optimal TSH cutoff value was 0.02 μU/mL (sensitivity 80%, specificity 93%) for prediction of diagnostic yield. Conclusion This study demonstrates that TSH is a useful predictor of the utility of TUS in yielding an etiology of thyrotoxicosis. Our analysis showed that TUS had a greater likelihood of determining an etiology when TSH was ≤0.02 μU/mL. This information can help clinicians avoid unnecessary cost and patient time burden when TUS is unlikely to aid in determining the etiology of thyrotoxicosis.

New-onset graves\u2019 disease after the initiation of nivolumab therapy for gastric cancer: a case report

BackgroundImmune checkpoint inhibitors (ICIs) can induce immune-related adverse events (irAEs) including thyroid dysfunction. There are only a few reports on Graves’ disease induced by ICIs. We report a case of new-onset Graves’ disease after the initiation of nivolumab therapy in a patient receiving gastric cancer treatment.Case presentationThe patient was a 66-year-old Japanese man, who was administered nivolumab (240 mg every 3 weeks) as a third-line therapy for stage IVb gastric cancer. His thyroid function was normal before the initiation of nivolumab therapy. However, he developed thyrotoxicosis before the third administration of nivolumab. Elevated, bilateral, and diffuse uptake of radioactive tracer was observed in the 99mTc-pertechnetate scintigraphy. Furthermore, the thyroid-stimulating hormone receptor antibody (TRAb) and thyroid-stimulating antibody (TSAb) test results, which were negative before the first administration of nivolumab, were positive after starting the therapy. The patient was diagnosed with Graves’ disease, and the treatment with methimazole and potassium iodide restored thyroid function.ConclusionsThis is the first complete report of a case of new-onset Graves’ disease after starting nivolumab therapy, confirmed by diffusely increased thyroid uptake in scintigraphy and the positive conversion of antibodies against thyroid-stimulating hormone receptor. It is important to perform thyroid scintigraphy and ultrasonography to accurately diagnose and treat ICI-induced thyrotoxicosis, because there are various cases in which Graves’ disease is developed with negative and positive TRAb titres.

Evaluating Focal 18F-FDG Uptake in Thyroid Gland with Radiomics.

The aim of this study was to evaluate the ability of 18F-FDG PET/CT texture analysis to predict the exact pathological outcome of thyroid incidentalomas. 18F-FDG PET/CT images between March 2010 and September 2018 were retrospectively reviewed in patients with focal 18F-FDG uptake in the thyroid gland and who underwent fine needle aspiration biopsy from this area. The focal uptake in the thyroid gland was drawn in 3D with 40% SUVmax threshold. Features were extracted from volume of interest (VOI) using the LIFEx package. The features obtained were compared in benign and malignant groups, and statistically significant variables were evaluated by receiver operating curve (ROC) analysis. The correlation between the variables with area under curve (AUC) value over 0.7 was examined; variables with correlation coefficient less than 0.6 were evaluated with machine learning algorithms. Sixty patients (70% train set, 30% test set) were included in the study. In univariate analysis, a statistically significant difference was observed in 6 conventional parameters, 5 first-, and 16 second-order features between benign and malignant groups in train set (p < 0.05). The feature with the highest benign-malignant discriminating power was GLRLMRLNU (AUC:0.827). AUC value of SUVmax was calculated as 0.758. GLRLMRLNU and SUVmax were evaluated to build a model to predict the exact pathology outcome. Random forest algorithm showed the best accuracy and AUC (78.6% and 0.849, respectively). In the differentiation of benign-malignant thyroid incidentalomas, GLRLMRLNU and SUVmax combination may be more useful than SUVmax to predict the outcome.

Diagnostic value of clinical parameters and parathyroid scintigraphy for asymptomatic primary hyperparathyroidism.

The purpose of this study was to evaluate the diagnostic value of clinical parameters and parathyroid scintigraphy for asymptomatic primary hyperparathyroidism (aPHPT), including quantitative parameter of laboratory and semiquantitative parameters derived from technetium-99m- metoxyisobutylisonitrile (99mTc-MIBI) single photon emission computed tomography/computed tomography (SPECT/CT). Two hundred and fourteen patients who had been diagnosed as PHPT and underwent surgical treatment were enrolled in this study. All patients were divided into two groups: aPHPT and symptomatic PHPT (sPHPT). Dual tracer 99mTc pertechnetate/99mTc-MIBI, dual time point and tomography scintigraphy with 99mTc-MIBI SPECT/CT were performed. Clinical parameters included basic information, serum calcium (Ca), phosphorus (P), parathyroid hormone (PTH) and alkaline phosphatase (ALP) levels. Semiquantitative parameters of parathyroid scintigraphy included the average counts of early parathyroid (PT1), late parathyroid (PT2), early thyroid (T1) and late thyroid (T2), the ratio of PT1/ T1 (R1), the ratio of PT2/ T2 (R2), parathyroid washout (PTW=(PT1-PT2)/PT1) and retention index (RI=(R2-R1)/R1). P<0.05 was considered as statistically significant. A total of 167 aPHPT patients (46 males, 121 females) were studied. One hundred and seventy four One hundred and seventy four174 parathyroid glands were removed after operation: 146 (87.4%) lesions were adenoma, 12 (7.2%) lesions were hyperplasia and 1 (0.6%) lesion was adenocarcinoma. There were significant differences in previous history (P=0.000), echo of parathyroid (P=0.004), thyroid function (P=0.029), clinical course (Z=-3.422, P=0.001), 99mTc-pertechnetat thyroid uptake (TcTU) (Z=-2.126, P=0.033), serum Ca level (t=-2.926, P=0.004) and serum PTH level (Z=-3.028, P=0.002) between aPHPT and sPHPT. For patients with aPHPT, there were significant differences for serum Ca level (t=2.832, P=0.005), R2 (Z=-2.597, P= 0.009) and RI (Z=-2.100, P=0.036) between adenoma and hyperplasia, and serum Ca level in aPHPT patients with adenoma was significantly higher compared with patients with hyperplasia. The areas under the curve (AUC) of clinical course, TcTU, serum Ca and PTH levels were 0.662, 0.399, 0.642 and 0.645 respectively for differential diagnosis of aPHPT and sPHPT. The AUC of R2 and RI were 0.737 and 0.692 respectively for differential diagnosis of adenoma and hyperplasia in patients with aPHPT. The sensitivity, negative predictive value (NPV) and accuracy for diagnosing aPHPT combined 99mTc-MIBI SPECT/CT with ultrasound (US) were significantly higher than dual tracer, dual time point, 99mTc-MIBI SPECT/CT and US, which were 97.5%, 95.2% and 55.6% respectively. Laboratory inspection and semi-quantitative parameters of parathyroid scintigraphy had higher value for differential diagnoses of aPHPT and sPHPT, the same for adenoma and hyperplasia in patients with aPHPT. When combined 99mTc-MIBI SPECT/CT with US, the diagnostic efficiency would be significantly improved.

Thyroid scintigraphy in diagnosis of nodular and diffuse thyroid pathology

Diagnosis of the causes of thyrotoxicosis (destruction or increased functional activity of the thyroid tissue in nodular and diffuse thyroid pathology) is a key point in determining the management of patients with this pathology. Scintigraphy is the method of choice in differential diagnosis of the causes of thyrotoxicosis assessing the functional state of the thyroid gland. According to variable medical interest, thyroid scintigraphy can be performed using 99mTc-pertechnetate or radioactive iodine isotopes (123I, 124I, 131I). For thyroid uptake evaluation used scintigraphy with 99mTc-pertechnetate radiopharmaceutical, which is not organificates and quickly excretes from thyroid tissue. In case of thyroid iodine pharmacokinetics investigation radiopharmaceuticals labeled by iodine isotopes (123I,131I, 124I) are used. The review includes original scintigrams, tables and diagrams. Article shows thyroid scintigraphy informativity analysis, evaluates the place and role of the thyroid scintigraphy examinations in modern diagnostic algorithms taking into account the history of the disease, laboratory tests, ultrasound (TIRADS) and result ofFNA (Bethesda). Additionally authors focused on existing clinical guidelines analysis. An optimized algorithm for the diagnosis and treatment of diffuse and/or nodular thyroid pathology associated with thyrotoxicosis is proposed.

Estudio prospectivo comparativo de dos métodos de cálculo individual de la actividad de 131I en el tratamiento del hipertiroidismo

ObjectiveRadioiodine (131I) is an established modality of definitive treatment of hyperthyroidism. In spite of the vast experience available, there are still several aspects to be clarified, such as whether fixed or calculated doses should be used. The aim of this study was to assess whether efficacy of this treatment could be improved by implementing a simple dosimetric calculation method including ultrasonographic estimation of thyroid volume and a single measurement of 24-hour 131I thyroid uptake. MethodsA prospective non-inferiority study was designed to compare two procedures to calculate radioiodine activity: the «semi-fixed» dose method (A), and the «calculated» dose method (B). The first consisted of activity escalation (185MBq steps) based on etiology of hyperthyroidism, 131I uptake, and treatment objective. The second method was based on the «dosimetric compromise» concept, considering 24-hour uptake and thyroid volume as the only factors and using a standard half-life of 5.5 days. The target absorbed dose was 150Gy, but after a preliminary analysis (first 100 cases) it was increased to 200Gy in diffuse toxic goiters (DTGs). ResultsA total of 212 patients were included. MethodB was at least as effective in terms of final and functional outcome, with a trend to more success and less hypothyroidism. In addition, activities administered were significantly lower. ConclusionIn radioiodine therapy of hyperthyroidism, a simple dosimetric method that provided results at least equal to those of a fixed dose-based method, with lower administered activities, could be implemented.

Radioiodine Therapy-Induced Conversion of Toxic Adenoma to Graves’ Disease

We present a 50-year-old female who was evaluated for the symptoms of thyrotoxicosis. She had low thyroid stimulating hormone (TSH) 0.02 with normal free thyroxine (FT4) 1.00 (0.61-1.76 ng/dL) and normal total triiodothyronine (TT3) 1.0 (0.60-2.20 ng/mL) levels. Her thyrotropin receptor antibody (TRAbs) and thyroid peroxidase antibody (TPOAb) titers were negative. Thyroid ultrasound revealed an ill-defined, heterogeneous, 1.8 cm x 0.8 cm x 0.7 cm nodule in the left lower lobe. 123-radioiodine (RAI) thyroid scan revealed 38.5% uptake, which was concentrated in the lower left thyroid lobe, a finding consistent with a solitary toxic adenoma of the thyroid.The patient became clinically and biochemically euthyroid on methimazole (MMI). She then underwent 131-RAI therapy with 12 mCi, which cured her hyperthyroidism with normalization of TSH levels for four months. She then developed overt thyrotoxicosis with low TSH of 0.02, elevated TT3 of 3.2, and normal FT4 of 0.91. Repeat TRAbs and TPOAb were elevated along with diffusely increased uptake on the I-123 RAI thyroid uptake scan, consistent with Graves’ disease (GD). The patient was then placed on MMI again to bridge to definitive treatment with total thyroidectomy. Our case is a rare case where the patient with solitary toxic adenoma with negative TPOAb serology developed GD following I-131 RAI treatment.

Fixed 30 mCi 131I-iodine therapy without recombinant human thyroid-stimulating hormone stimulation as an attractive therapeutic alternative in nontoxic nodular goiter.

To analyze outcomes of patients with compressive nontoxic multinodular goiter after 131I-iodine 30 mCi treatment without previous use of recombinant human thyroid-stimulating hormone or methimazole. We evaluated fixed-dose radioiodine therapy outcomes in patients with nontoxic multinodular goiter who did not accept thyroidectomy as a therapeutic option. Laboratory thyroid function and thyroid volume estimated by ultrasound were assessed before and one year after radioiodine therapy. Twenty euthyroid female patients received 30 mCi of 131I-iodine without recombinant human thyroid-stimulating hormone or methimazole pretreatment. Median thyroid volume and Tc-99m sodium pertechnetate thyroid uptake before radioiodine therapy were 68.05 cm (31.3-295.3) and 0.5% (0.1%-1.2%), respectively. One year after radioiodine therapy, thyroid volume decreased to 55.4 cm (19.8-149.9), and merely 4 patients (20%) developed hypothyroidism. Thyroid volume decreased significantly after radioiodine therapy, presenting a variation of -21.1 cm (-161.3 to -0.8) and -30.61% (-73.88 to -1.02), both with P < 0.0001. Thyroid volume variation was positively correlated with thyroid uptake in Spearman's correlation (r = 0.4730; P = 0.0352). The group satisfied with radioiodine therapy (85%, n = 17) showed a significant reduction in thyroid volume, -25.8 cm (-161.3 to -6.2) and -36.74% (-73.88 to -9.95). The dissatisfied group (15%, n = 3) showed -1.0 cm (-2.0 to -0.8) and -1.67% (-3.38 to -1.02) in thyroid volume, P = 0.0081. Patients that complained about dysphagia presented a lower percentage of thyroid volume decrease after radioiodine therapy, -21.97% (-70.12 to -1.02, P = 0.0430). A substantial reduction in thyroid volume associated with a low incidence of hypothyroidism and a high satisfaction rate support the use of conventional radioiodine therapy with a fixed dose of 30 mCi. This therapy is an attractive and cheaper therapeutic alternative in selected patients with nontoxic multinodular goiter.

How Hybrid PET/CT Improve Pitfalls and Artifacts in Malignant Lymphoma?

18F-FDG PET/CT has become a standard procedure for the evaluation of lymphomas. An understanding of the role of FDG PET/CT in the management of lymphomas and knowledge of its limitations is mandatory for the optimal utilization of this technique. The present study aimed to assist accurate interpretation with proper diagnosis by exclusion of false positive or false negative causes of PET/CT studies. Material and Methods: This retrospective study included 105 adult patients with malignant lymphoma to diagnose possible pitfalls during study interpretation. All clinical and histopathological information were extracted from the patients’ clinical sheet. Results: The study included 105 patients (48patients with HD and 57 patients with NHL). The mean age of all patients was (46.78 ± 16.78) years.The majority of patients were males (61.9%); while (38.1%) were females. Total numbers of pitfalls detected were 373 sites. Physiological Pitfalls were detected in 71 sites, (36 sites had muscle uptake 12 sites had uterine-related uptake pitfalls, 12 sites had brown adipose tissue uptake and 5 sites had unilateral vocal cord uptake. Technical pitfalls were detected in 128 sites (50 sites had contrast-induced artifacts,41 sites had head movement, 36 sites had metallic artifact and one site showed truncation related pitfalls). Therapy related artifacts were detected in 156 sites (56 sites had gastric uptake. 54 sites had splenic & BM uptake and 30 patients had enhanced salivary uptake, while, 6 sites had diminished salivary uptake, 6 patients had thymic hyperplasia and 4 patients had early and late radiation effect). Benign pathological benign conditions were detected in18 sites (9 sites had incidental thyroid uptake and 8 patients had inflammatory lung uptake and one patient had bone fracture). Conclusion: PET/CT is a powerful imaging technique for characterizing pathological lymphomatous lesions with proper evaluation of physiological, technical and post therapy pitfalls or artifacts.

Thyroid uptake test with portable device (COTI) after 131I tracer administration: proof of concept.

COTI (collar therapy indicator) has been recently introduced for the detection of gamma rays with emphasis on thyroid investigations. The aim of this study was to test the feasibility of a prototype version of COTI including activity detectors with low sensitivity in performing thyroid uptake measurements for a large group of patients. Consequently, thyroid uptake tests were carried out for a total of 89 patients (22 males and 67 females; age: 44 ± 13years) with thyroid cancer (n = 74), hyperthyroidism (n = 16) at 2 and 24h after administration of 0.44-2MBq of 131I. Eight individuals among the thyroid cancer patients were monitored up to 96h after administration. The COTI device was equipped with two CsI (Tl) detectors, known as LoHi type, sensitive to activity ranges from 0.02 to 30MBq of 131I. The uptake values from COTI were compared with those measured with a standard probe. It was found that the mean uptake of thyroid activity in thyroid cancer patients was 2.1 ± 1.3% at 2h when measured with the standard probe, while it was 2.2 ± 1.2% when measured with COTI. In addition, the average uptake at 24h after administration was 2.5 ± 3.2% and 3.2 ± 3.8% measured with COTI and the standard probe, respectively. A strong correlation was found at 24h between the results obtained with COTI and the standard probe, while a weaker correlation was seen at 2h. Overall, there was no significant difference between the results obtained with the standard probe and those obtained with COTI at both 2 and 24h (Pvalue ≥ 0.05). Besides, 85% of the uptake values measured with COTI were less than those measured with the standard probe at the 24h after administration. The average uptake value was 0.9 ± 0.8% after 96h by COTI, and 1.4 ± 1.3% by the standard probe. Pertaining to the hyperthyroidism patients, COTI showed mean uptake values of 20 ± 16% and 23 ± 18% at 2 and 24h, respectively. In contrast, the standard probe suggested higher mean uptake values of 26 ± 18% and 30 ± 22%, respectively. It is concluded that the prototype of COTI used in the present study has been proved to be a feasible and promising tool in thyroid investigations. It is noted, however, that the next COTI generation should include detectors equipped with collimator and energy discrimination.