BRAF Detection in FNAC Combined with Semi-Quantitative 99mTc-MIBI Technique and AI Model, an Economic and Efficient Predicting Tool for Malignancy in Thyroid Nodules.

BACKGROUND: Technology allows us to predict a histopathological diagnosis, but the high costs prevent the large-scale use of these possibilities. The current liberal indication for surgery in benign thyroid conditions led to a rising frequency of incidental thyroid carcinoma, especially low-risk papillary micro-carcinomas. METHODS: We selected a cohort of 148 patients with thyroid nodules by ultrasound characteristics and investigated them by fine needle aspiration cytology (FNAC)and prospective BRAF collection for 70 patients. Also, we selected 44 patients with thyroid nodules using semi-quantitative functional imaging with an oncological, 99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) radiotracer. RESULTS: Following a correlation with final histopathological reports in patients who underwent thyroidectomy, we introduced the results in a machine learning program (AI) in order to obtain a pattern. For semi-quantitative functional visual pattern imaging, we found a sensitivity of 33%, a specificity of 66.67%, an accuracy of 60% and a negative predicting value (NPV) of 88.6%. For the wash-out index (WOind), we found a sensitivity of 57.14%, a specificity of 50%, an accuracy of 70% and an NPV of 90.06%.The results of BRAF in FNAC included 87.50% sensitivity, 75.00% specificity, 83.33% accuracy, 75.00% NPV and 87.50% PPV. The prevalence of malignancy in our small cohort was 11.4%. CONCLUSIONS: We intend to continue combining preoperative investigations such as molecular detection in FNAC, 99mTc-MIBI scanning and AI training with the obtained results on a larger cohort. The combination of these investigations may generate an efficient and cost-effective diagnostic tool, but confirmation of the results on a larger scale is necessary.

Comparative Analysis of Diagnostic Efficacy in Primary Hyperparathyroidism: A Comparison Analysis of 11C-Choline PET/CT, Neck Ultrasonography, 99mTc-MIBI Dual-Phase Planar Scintigraphy, and 99mTc-MIBI SPECT/CT Imaging.

Objective: To compare the diagnostic efficacy of 11C-choline PET/CT, neck ultrasonography, 99mTc-MIBI dual-phase planar scintigraphy, and 99mTc-MIBI SPECT/CT imaging in the diagnosis of primary hyperparathyroidism (PHPT). Methods: We conducted a retrospective analysis of 32 patients with PHPT who visited the Nuclear Medicine Department of Jilin University China-Japan Union Hospital between January 2019 and December 2022. All patients underwent 11C-choline PET/CT, neck ultrasonography, 99mTc-MIBI dual-phase planar scintigraphy, and 99mTc-MIBI SPECT/CT examinations within two months before surgery. Sensitivity, specificity, positive predictive value, and negative predictive value of each imaging study were compared using postoperative pathology and follow-up results. Diagnostic efficacy was further analyzed using ROC curve analysis. Factors influencing on 99mTc-MIBI imaging were also investigated. Results: A total of 35 lesions were resected in the 32 patients. The diagnostic sensitivity of 11C-choline PET/CT, neck ultrasonography, 99mTc-MIBI dual-phase planar scintigraphy, and 99mTc-MIBI SPECT/CT was 88.2%, 52.9%, 58.8%, and 67.6%, respectively. Specificity was 96.8%, 95.7%, 96.8%, and 95.7%, respectively. Positive predictive values were 90.9%, 81.8%, 86.9%, and 85.2%, respectively, and negative predictive values were 95.7%, 84.9%, 86.7%, and 89.1%, respectively. The areas under the ROC curve (AUC) were 0.925, 0.743, 0.778, and 0.817, respectively. Among them, 11C-choline PET/CT had higher sensitivity and AUC than other imaging studies (p<0.05), while specificity, positive predictive value, and negative predictive value were similar (p>0.05). The positive group in 99mTc-MIBI SPECT/CT imaging had significantly larger lesion diameters than the negative group (P<0.05), while preoperative blood calcium and PTH showed no statistical differences (P>0.05). Conclusion: 11C-choline PET/CT demonstrates superior preoperative diagnostic efficacy for PHPT compared to neck ultrasonography, 99mTc-MIBI dual-phase planar scintigraphy, and 99mTc-MIBI SPECT/CT. Lesion size may be the primary factor affecting the sensitivity of 99mTc-MIBI imaging.

99mTc-methoxyisobutylisonitrile single-photon emission computed tomography/computed tomography parathyroid imaging in the diagnosis of functional parathyroid cysts: an initial experience.

Background: Functional parathyroid cysts (FPCs) are rare and difficult to diagnose with noninvasive methods. The aim of this study was to evaluate the diagnostic value of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) single-photon emission computed tomography/computerized tomography (SPECT/CT) parathyroid imaging in the diagnosis of FPCs and to account for its performance. Methods: The data from 10 patients with suspected parathyroid cysts (PCs) who underwent 99mTc-MIBI SPECT/CT parathyroid imaging between 2012 and 2022 were retrospectively evaluated. The diagnostic value of 99mTc-MIBI SPECT/CT parathyroid imaging for FPCs was analyzed. Results: Surgical resection was performed in six cases and parathyroid puncture was performed in four cases. The sensitivity of 99mTc-MIBI SPECT/CT for FPCs was 100.0% (3/3), with a specificity of 100.0% (7/7) and an accuracy of 100.0% (10/10). The postoperative pathological findings in three cases of FPCs were parathyroid adenoma, parathyroid adenoma with hemorrhage, and parathyroid adenoma with cystic degeneration, respectively. The diagnostic accuracy of ultrasound and CT for PCs was only 22.22% (2/9) and 25.0% (1/4), respectively, and neither modality could indicate whether the cysts were functional or not. Conclusions: 99mTc-MIBI parathyroid SPECT/CT imaging has a high value in the diagnosis of FPCs in patients with suspected PCs, and an intense ring-shaped accumulation of radioactivity in the cyst wall on 99mTc-MIBI imaging suggests that the patient may have FPCs.

Analysis of false-positive and false-negative results in 99mTc-MIBI SPECT/CT parathyroid imaging.

Background: Exact preoperative localization is desirable to perform minimally invasive parathyroidectomy for hyperparathyroidism (HPT). This study aimed to evaluate the diagnostic values of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) single photon emission computed tomography/computed tomography (SPECT/CT) of parathyroid glands by analyzing the relationship between lesion weight and false-negative (FN) results, as well as to explain the possible reason. Methods: The data from 314 patients with suspected HPT who underwent 99mTc-MIBI SPECT/CT parathyroid imaging between 2011 and 2022 were retrospectively evaluated. The sensitivity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of parathyroid 99mTc-MIBI SPECT/CT were calculated, and the false-positive (FP) and FN findings were analyzed. Results: Accurate localization by 99mTc-MIBI SPECT/CT was significantly associated with the parathyroid hormone (PTH) level. The 99mTc-MIBI SPECT/CT for diagnosis/lesion location reached a sensitivity of 84.6%/56.8%, a PPV of 97.3%/98.4%, an NPV of only 23.7%/4.18%, and an accuracy of 83.4%/57.1%, respectively. The largest diameter, shortest diameter, and lesion volume were lower in the FN group than in the TP group. A total of 7 FP cases were found, including 2 cases of thyroid nodules, 4 cases of thyroid tissue, and 1 case of hibernoma. A total of 45 FN patients, including 321 FN lesions, were confirmed, of which parathyroid hyperplasia accounted for 97.8%. Lesion weights greater than 20 µg were able to be detected, but lightweight lesions less than 100 mg were the principal source of FN results, accounting for approximately 39.3%. With lesion weights 0-100, 101-300, 301-1,000, and >1,000 mg, the FN rate was 70.8% (126/178), 51.8% (103/199), 34.6% (81/234), and 8.33% (11/132), respectively. Conclusions: 99mTc-MIBI SPECT/CT parathyroid imaging provides good sensitivity and high specificity in HPT location. Correct localization by 99mTc-MIBI SPECT/CT correlates positively with lesion weight and PTH levels. The smaller the lesion, the higher the FN rate in 99mTc-MIBI SPECT/CT parathyroid imaging, and lesions weighing less than 100 mg are the main source of FN results in 99mTc-MIBI SPECT/CT parathyroid imaging.

Quantitative application of dual-phase 99mTc-sestamibi SPECT/CT imaging of parathyroid lesions: identification of optimal timing in secondary hyperparathyroidism.

PURPOSE: In this retrospective study, we compared the maximum standardized uptake values (SUVmax) of parathyroid lesions and the target-to-background ratio (TBR) of parathyroid lesions to thyroid tissue in early-phase single-photon emission computed tomography/computed tomography (SPECT/CT) versus delayed-phase SPECT/CT in patients with secondary hyperparathyroidism (SHPT) in order to determine the optimal timing of 99mTc- methoxyisobutylisonitrile (99mTc-MIBI) SPECT/CT imaging. METHODS: Seventeen patients with a history of chronic kidney failure stage 5 on hemodialysis, underwent pre-operative parathyroid scintigraphy for detection and localization of parathyroid lesions. Retrospective analysis was conducted for lesions with focal accumulation of 99mTc-MIBI. All patients underwent dual-phase 99mTc-MIBI parathyroid scintigraphy and dual-phase SPECT/CT. SUVmax of parathyroid lesions and thyroid tissues was measured. RESULTS: Mean SUVmax of parathyroid lesions was 4.86 on early-phase and 2.58 on delayed-phase SPECT/CT, respectively. Mean TBR was 1.14 on early phase and 1.48 on delayed-phase SPECT/CT, respectively. Statistically significant differences in SUVmax and TBR between dual-phase SPECT/CT were observed (P < 0.001). CONCLUSIONS: Delayed-phase SPECT/CT in SHPT is required because of the better image contrast.

Hyperfunctioning Intrathyroidal Parathyroid: a Misleading Preoperative Diagnosis.

Hyperfunctioning parathyroid glands may be rarely located in the thyroidal parenchyma and not identified by imaging or during surgical procedures. We present three patients with primary hyperparathyroidism related to hyperfunctioning intrathyroidal parathyroid retrospectively selected among 732 cases from own Institutional parathyroid PET/CT registry from 2018 to 2022. Intrathyroidal parathyroids showed intense 18F-fluorocholine uptake but a variable echographic pattern, inconstant 99mTc-MIBI uptake, and atypic iodine-contrast enhancement. Although rare, the possibility of an intrathyroidal parathyroid should be considered when no hyperfunctioning gland is found on preoperative imaging and thorough bilateral neck exploration.

Quantitative model for assessment of lower-extremity perfusion in patients with diabetes.

BACKGROUND: Although diabetic and atherosclerotic vascular diseases have different pathophysiological mechanisms, the screening methods currently used for diabetic lower-extremity vascular diseases are mainly based on the evaluation methods used for atherosclerotic vascular diseases. Thus, assessment of microvascular perfusion is of great importance in early detection of lower-extremity ischemia in diabetes. PURPOSE: This cross-sectional study aimed to develop a quantitative model for evaluating lower-extremity perfusion. METHODS: We recruited 57 participants (14 healthy participants and 43 diabetes patients, of which 16 had lower-extremity arterial disease [LEAD]). All participants underwent technetium-99 m sestamibi (99mTc-MIBI) scintigraphy and ankle-brachial index (ABI) examination. We derived two key perfusion kinetics indices named activity perfusion index (API) and basal perfusion index (BPI). This study was registered in ClinicalTrials.gov (URL: https://www. CLINICALTRIALS: gov, NCT02752100). RESULTS: The estimated limb perfusion values in our lower-extremity perfusion assessment (LEPA) model showed excellent consistency with the actual measured data. Diabetes patients showed reduced lower-extremity perfusion in comparison with the control group (BPI: 106.21 ± 11.99 vs. 141.56 ± 17.38, p < 0.05; API: 12.34 ± 3.27 vs. 14.56 ± 3.12, p < 0.05). Using our model, the reductions in lower-extremity perfusion could be detected early in approximately 96.30% of diabetes patients. Patients with LEAD showed more severe reductions in lower-extremity perfusion than diabetes patients without LEAD (BPI: 47.85 ± 20.30 vs. 106.21 ± 11.99, p < 0.05; API: 7.06 ± 1.70 vs. 12.34 ± 3.27, p < 0.05). Discriminant analysis using API and BPI could successfully screen all diabetes patients with LEAD with a sensitivity of 100% and specificity of 80.77%. CONCLUSIONS: We established a LEPA model that could successfully assess lower-extremity microvascular perfusion in diabetes patients. This model has important application value for the recognition of early-stage LEAD in patients with diabetes.

Utility of 99mTc-Sestamibi Heart/Liver Uptake Ratio in Screening Nonalcoholic Fatty Liver Disease During Myocardial Perfusion Imaging.

Purpose: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic hepatic disease worldwide, with functional impairment of the mitochondria occurring from early stages. Technetium-99m methoxy-isobutyl-isonitrile (99mTc-MIBI) is a lipophilic agent trapped in the mitochondria. This study aims to evaluate the utility of 99mTc-MIBI heart/liver uptake ratio in screening for NAFLD during myocardial perfusion imaging (MPI). Methods: Seventy eligible patients underwent a 2-d rest/stress 99mTc-MIBI scan with a 2-min planar image acquired in rest phase, at 30, 60, and 120 min postradiotracer administration. Heart/liver uptake ratio was calculated by placing identical regions of interest on the heart and liver dome. All patients underwent liver ultrasound and were allocated into groups A, having NAFLD; and B, healthy individuals without NAFLD. Results: Mean count per pixel heart/liver ratios gradually increased over time in either group; nonetheless the values were significantly higher in group A, regardless of acquisition timing; with the p-value equal to 0.007, 0.014, and 0.010 at 30, 60, and 120 min, respectively. Conclusion: Determining 99mTc-MIBI heart/liver uptake ratio during rest phase in patients undergoing MPI may be a useful, noninvasive screening method for NAFLD; with no additional cost, radiation burden, or adverse effects in these patients. Trial registration number: IR.SBMU.MSP.REC.1398.308.

The usefulness of [99mTc]MIBI scintigraphy in the diagnostic algorithm of ultrasonographical suspected thyroid nodules by using EU-TIRADS criteria.

BACKGROUND: Although not yet involved in the algorithm of thyroid nodules, 99mTc-methoxy-isobutyl-isonitrile ([99mTc]MIBI) scintigraphy may help in the individual diagnostic workup of a thyroid patient, especially where indeterminate fine needle aspiration biopsy (FNAB) is present. The aim of this study was to evaluate the usefulness of [99mTc]MIBI thyroid scintigraphy in the diagnostic algorithm of thyroid nodules, particularly in ultrasound EU-TIRADS 4 or 5 lesions, that cytologically were either indeterminate or benign. MATERIAL AND M: ETHODS: A retrospective randomized study, including 42 thyroid patients, with mean age 47 ± 17 years, was conducted. [99mTc]MIBI scan was compared with ultrasound (US) EU-TIRADS criteria, pertechnetate scan, FNAB and histopathological findings for the differentiation of malignant thyroid nodules from benign lesions. RESULTS: The US mainly detected hypoechoic inhomogeneous presentation of the thyroid nodules (35/42, 83.33%), 4 cases with isoechoic nodules and 2 cases presented with hyperechoic thyroid nodules. Histopathology revealed malignancy in 15/42 (35.71%), while all other patients 27/42 (64.29%) were benign. Visual analysis score showed that patients scored with 1+ and 2+ were statistically significant to be benign, while 13 vs. 10 pts that were visual score 3+ were malignant vs. benign (p > 0.05). Sensitivity was 100%, while specificity was very low 22.22%, PPV was 41.67%. CONCLUSIONS: Even [99mTc]MIBI scan is not routinely used as a daily practice diagnostic tool of thyroid nodules, we will further apply it on a larger group of patients and try to quantify the uptake of the radiotracer to see whether it will help in the diagnostic algorithm of thyroid nodules.

Advances in the treatment of secondary and tertiary hyperparathyroidism.

Secondary hyperparathyroidism (SHPT) and tertiary hyperparathyroidism (THPT) are common and complicated clinical endocrine diseases. The parathyroid glands maintain endocrine homeostasis by secreting parathyroid hormone to regulate blood calcium levels. However, structural alterations to multiple organs and systems occur throughout the body due to hyperactivity disorder in SHPT and THPT. This not only decreases the patients' quality of life, but also affects mortality. Since current treatments for these diseases remains unclear, we aimed to develop a comprehensive review of advances in the treatment of SHPT and THPT according to the latest relevant researches.

A case of ectopic cervical thymoma with myasthenia gravis mimicking a parathyroid tumour.

Reports of cervical thymoma with myasthenia gravis are rare. In addition, 99mTc-MIBI (methoxyisobutylisonitrile:sestamibi) scintigraphy is a useful diagnostic examination for enlarged parathyroid tumours; however, there are a few reports of its accumulation in thymoma. Among them, there are no reports of cervical thymomas with 99mTc-MIBI accumulation complicated by myasthenia gravis. In this study, we performed surgery on a patient with preoperative myasthenic crisis accompanied by a cervical thymoma and a parathyroid tumour. Preoperatively, the cervical mass was determined to be a parathyroid tumour and was complicated by myasthenia gravis without thymic tumour. However, a pathological examination revealed that the cervical tumour with 99mTc-MIBI accumulation was a Type B2 thymoma, and a parathyroid tumour was identified in the vicinity. We report a very rare case in which symptoms improved with surgery.

Optimal timing of SPECT/CT to demonstrate parathyroid adenomas in 99mTc-sestamibi scintigraphy.

BACKGROUND: Accurate preoperative localisation of the parathyroid adenoma is essential to achieve a minimally invasive parathyroidectomy. The purpose of this study was to validate and improve our single-isotope dual-phase parathyroid imaging protocol utilising 99mTechnetium-Sestamibi ([99mTc]MIBI). There has been no accepted gold standard evidence-based protocol regarding timing of single-photon emission computed tomography/computed tomography (SPECT/CT) acquisition in parathyroid imaging with resultant variation between centres. We sought to determine the optimum timing of SPECT/CT post administration of [99mTc]MIBI in the identification of parathyroid adenomas. We aimed to evaluate the efficacy of early and late SPECT/CT and to establish whether SPECT/CT demonstrates increased sensitivity over planar imaging. MATERIAL AND METHODS: A sample of 36 patients with primary hyperparathyroidism underwent planar and SPECT/CT acquisition 15 minutes (early) and two hours (late) post [99mTc]MIBI administration. Two radionuclide radiologists reviewed the images and Fisher's exact Chi-squared statistic was used to evaluate the diagnostic performances of early versus late SPECT/CT acquisition and SPECT/CT versus planar imaging. RESULTS: Twenty-one likely parathyroid adenomas were identified with a statistically superior diagnosis rate in the late SPECT/CT acquisition compared with both early SPECT/CT and planar imaging (p < 0.05). All adenomas diagnosed on early SPECT/CT acquisition were also identified on late SPECT/CT images. CONCLUSIONS: Single late phase SPECT/CT is significantly superior to early SPECT/CT in the identification of parathyroid adenomas. Late SPECT/CT improves diagnostic accuracy over planar acquisition. Imaging protocols should be revised to include late SPECT/CT acquisition. Early SPECT/CT acquisition can be eliminated from scan protocols with associated implications regarding reduced scan time and increased patient throughput.

COVID-19 pneumonia detected by parathyroid scintigraphy.

We report a case of incidental diagnosis of COVID-19 pneumonia by parathyroid scintigraphy. A 53-year-old woman who had severe fatigue, and mild dyspnea underwent parathyroid scintigraphy due to increased serum parathyroid hormone (PTH) and serum calcium levels. Parathyroid scan was negative for abnormal parathyroid tissue. Although the patient had three negative results of COVID-19 PCR tests, significant 99m Tchexakis-2-methoxyisobutylisonitrile ([99mTc]MIBI) uptake is noticed in both lungs that was suspicious for Covid-19 pneumonia. The patient underwent CT scan of the chest for further evaluation. Diffuse groundglass opacities were identified in both lungs which were interpreted as typical feature for COVID-19 pneumonia.

Diagnostic Performance of 99mTc-Methoxy-Isobuty-Isonitrile (MIBI) for Risk Stratification of Hypofunctioning Thyroid Nodules: A European Multicenter Study.

99mTc-MIBI (MIBI) imaging is able to exclude malignancy of hypofunctioning thyroid nodules (TNs) with high probability but false positive results are frequent due to low specificity. Therefore, pre-test selection of appropriate TNs is crucial. For image evaluation visual and semiquantitative methods (Washout index, WOInd) are used. Aim of this study was to evaluate the diagnostic performance of MIBI imaging in hypofunctioning TNs with indeterminate fine-needle aspiration cytology results in a multicentric European setting. Patients with hypofunctioning TNs, EU-TIRADS 4 or 5, Bethesda III/IV and MIBI imaging were included. For visual evaluation the intensity of MIBI uptake in the TN was compared to normal thyroid tissue. 358 patients with 365 TNs (n = 68 malignant) were included. Planar imaging (SPECT) showed a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 96% (94%), 21% (22%), 22% (15%), 96% (96%), and 35% (32%). The WOInd (38.9% of all cases, optimal cutoff: -19%) showed a sens 100% (spec 89%, PPV 82%, NPV 100%, ACC 93%). For hypofunctioning TNs at intermediate or high risk with indeterminate cytology, a MIBI negative result on visual evaluation is an effective tool to rule-out thyroid malignancy. The semi-quantitative method could considerably improve overall diagnostic performance of MIBI imaging.

The feasibility of 18F-FDG gated positron emission tomography (PET) for left ventricular dyssynchrony assessment in comparison with 99mTc-MIBI gated single-photon emission computed tomography (SPECT) among patients with prior myocardial infarction.

Background: Phase analysis by 99mTc-MIBI gated single-photon emission computed tomography (GSPECT) has been considered to be an adequate method in the validation of left ventricular (LV) dyssynchrony. Compared with GSPECT, prior myocardial infarction patients with myocardial perfusion defects but myocardial viability usually show preserved uptake of 18F-FDG, and extensive myocardium is detected by 18F-FDG gated positron emission tomography (GPET). Thus, theoretically, it should be more accurate. The aim of this study was to investigate the feasibility of GPET for LV dyssynchrony assessment in comparison with GSPECT among infarction patients. Methods: A total of 146 patients with infarction underwent 2 consecutive days of GSPECT and GPET examinations. Quantitative gated SPECT-derived LV phase analysis was applied to GPET and GSPECT data to assess the presence of LV dyssynchrony via histogram bandwidth (BW) and phase standard deviation (SD). The correlation and agreement of BW and SD between GSPECT and GPET were examined. Factors (i.e., total perfusion defect, scar and mismatch) related to the discrepancies of LV dyssynchrony (i.e., BW and SD) in GPET and GSPECT were assessed by univariate and multivariate regression analysis. Results: A moderate correlation between GPET and GSPECT was found in the measurements of BW (r=0.554) and SD (r=0.537). Bland-Altman analysis revealed that GPET overestimated both BW and SD (20.5° and 9.5°, respectively). In addition, the BW and SD measured by GPET were still overestimated after subgroup analysis. Between GPET and GSPECT, multivariate regression analysis revealed that total perfusion defects were related to the difference in BW measurement (P<0.001), and mismatch was associated with the difference in SD measurement (P<0.01). Conclusions: In patients with infarction, GPET moderately correlated with GSPECT in assessing LV dyssynchrony. GPET overestimated both BW and SD, so these analyses should not be interchangeable in individual patients.

99mTc-MIBI SPECT/CT SCINTIGRAPHY AND ULTRASOUND OF THE ANTERIOR NECK REGION IN DIAGNOSING PARATHYROID GLAND PATHOLOGY IN PATIENTS WITH THYROID NODULES.

Parathyroid scintigraphy with 99mTc-MIBI is an imaging technique used in nuclear medicine and performed in patients with suspected hyperparathyroidism (HPT). The objective of this study was to evaluate the role of this technique in patients who, along with suspected HPT, also have thyroid nodules. Retrospective analysis included a period of 8 years (2006-2013). The study included 91 patients with clinical or laboratory suspected HPT. Pathologic changes in parathyroid glands were demonstrated in 47 (70%) of 67 patients with positive scintigraphy. Pathologic changes in parathyroid glands were not evident in the remaining 20 (30%) patients. Out of nine patients with negative scintigraphy results but with suspected enlargement of the parathyroid gland examined by ultrasound, eight (89%) patients did not show pathologic changes in the parathyroid gland, whereas one (11%) patient had evident changes. Eight (54%) of 15 patients with suspected scintigraphy had positive ultrasound findings, as well as fine needle aspiration cytology (FNAC) findings with parathyroid hormone (PTH) determination in the aspirate. Seven (46%) patients had negative FNAC findings and PTH in the aspirate. The study showed scintigraphy to have high sensitivity (98%) in detecting patients with pathologic changes in the parathyroid glands. In patients with suspected HPT, scintigraphy needs to be combined with FNAC and PTH determination in the aspirate due to its low specificity of 28%.

Preoperative imaging in primary hyperparathyroidism: Are 11 C-Choline PET/CT and 99m Tc-MIBI/123 Iodide subtraction SPECT/CT interchangeable or do they supplement each other?

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

18F-fluorocholine PET/CT and conventional imaging in primary hyperparathyroidism.

PURPOSE: The purpose of this study was to assess the diagnostic capabilities of preoperative conventional imaging (99mTc-MIBI scintigraphy, cervical ultrasonography [CUS]) and 18F-fluorocholine PET/CT (FCH PET/CT) in the detection of hyperfunctioning parathyroid gland in patients with primary hyperparathyroidism (PHPT) used alone or as a single imaging set. MATERIALS AND METHODS: A total of 51 consecutive patients (6 men, 45 women; mean age, 62 ± 11.6 [SD] years; age range: 28-86 years) with biochemically confirmed PHPT who underwent CUS, single-tracer dual phase 99mTc-MIBI scintigraphy and FCH PET/CT were retrospectively included. 99mTc-MIBI scintigraphy were performed immediately after CUS and interpreted by the same operators. FCH PET/CT examinations were interpreted independently by two nuclear medicine physicians. An additional reading session integrating the three imaging modalities read in consensus as a combined imaging set was performed. RESULTS: At surgery, 74 lesions were removed (32 parathyroid adenomas, 38 parathyroid hyperplasia and 4 subnormal glands). Thirty-six patients (71%) had single-gland disease and 15 patients (29%) had multiglandular disease at histopathological analysis. On a patient basis, sensitivity and accuracy of FCH PET/CT, CUS and 99mTc-MIBI scintigraphy for the detection of abnormal parathyroid glands were 76% (95% CI: 63-87%) and 76% (95% CI: 63-87%), 71% (95% CI: 56-83%) and 71% (95% CI: 56-83%), 33% (95% CI: 21-48%) and 33% (95% CI: 21-48%), respectively. The sensitivity of the combined imaging set was 94% (95% CI: 84-99%) and greater than the sensitivity of each individual imaging technique (P ≤ 0.001 for all). CONCLUSION: Our results suggest that CUS, 99mTc-MIBI scintigraphy and FCH PET/CT interpreted as a single imaging set could be the ideal practice to precisely localize parathyroid lesion in patients with PHPT before surgery.

Effect of proton pump inhibitors and H2 antagonists on gastric wall uptake in myocardial perfusion scan with 99mTc-sestamibi.

BACKGROUND: Proton pump inhibitors (PPIs) have been speculated to cause gastric wall uptake (GWU) in MPI scans. However, the uptake mechanism and prevention methods are less studied. In this prospective trial we aimed to evaluate the impact of gastroprotective medications on GWU and its solutions. METHODS: 351 consecutive patients, scheduled for 2-day rest/stress 99mTc-MIBI scan, were distributed into 5 groups. 3-7 days following the baseline rest scan, the stress scan was acquired after intervention in the trial group, consisting of patients with history of PPI intake, randomly assigned to 3 subgroups: discontinuing PPIs(A), replacement with H2 blockers (B), and continuing PPIs (C). Patients receiving H2 blockers, continued it as before (D) and the remaining patients were the control group (E). GWU was graded compared to the myocardial uptake. RESULTS: In the rest phase, all groups had significantly higher GWU compared to the control group. In the stress phase, group A had less GWU than group B (P-value < 0.05) and both of them had significantly less GWU compared to group C (P-value < 0.001). There was no significant difference between PPI discontinuation periods of 3-5 days versus 5-7 days. There was a significant association between duration of oral PPI intake, but not IV PPIs, and GWU. GWU was significantly lower with oral compared to IV PPI administration. CONCLUSION: PPIs significantly increase GWU and discontinuing them for at least 3-5 days significantly reduces GWU. H2 antagonists are a good alternative in patients who cannot tolerate dyspepsia symptoms.

Assessing the prevalence and predicting factors of an abnormal gated myocardial perfusion SPECT in asymptomatic patients with type 2 diabetes.

Considering the significant prevalence of silent myocardial ischemia and its related morbidity and mortality in asymptomatic type 2 diabetic patients, it is not well known whether early screening with MPI is cost-effective and predicting factors are not well elucidated. This was a cross-sectional study including 63 asymptomatic patients with type 2 diabetes mellitus (T2DM), with normal ECG and ejection fraction. Patients with any history of documented valvular, congestive or ischemic heart disease, renal or hepatic failure were excluded. At first all patients were interviewed and checked for risk factors and then patients underwent a two-day rest/stress 99mTc-MIBI gated MPI SPECT. Data was assessed by QPS/QGS and 4DM software and evaluated by a nuclear medicine specialist with summed stress score (SSS) of more than 4 defined as CAD. There were 42 females (67%) and 21 males (33%), with a mean age of 61.33 ± 6.98 years and 7.97 ± 4.86 years history of T2DM. CAD was detected in 26 (41.3%) patients and was significantly associated with male gender, smoking and requiring insulin therapy (P-value = 0.019, 0.046, 0.05, respectively). A significant association was found between the duration of diabetes, especially when > 15 years, and the probability of having CAD. Multivariable logistic regression revealed that smoking; male gender and diabetes duration were the strongest independent predictors of abnormal MPI results. We found a high (46%) prevalence of abnormal stress MPI SPECT in patients with type 2 diabetes mellitus, despite being asymptomatic. Asymptomatic patients with a history of smoking, long duration of diabetes, being under insulin treatment and male gender might benefit from MPI for early detection of silent ischemia.