Diagnostic Value of Volume-Based Fluorine-18-Fluorodeoxyglucose PET/CT Parameters for Characterizing Thyroid Incidentaloma

OBJECTIVE: To assess clinical value of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for differentiation of malignant from benign focal thyroid incidentaloma. MATERIALS AND METHODS: This retrospective study included 99 patients with focal thyroid incidentaloma of 5216 non-thyroid cancer patients that had undergone PET/CT. PET/CT semi-quantitative parameters, volume-based functional parameters, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of thyroid incidentaloma were assessed. Receiver-operating characteristic (ROC) analysis was conducted and areas under the curve (AUC) were compared by Hanley and McNeil test to evaluate usefulness of maximum standardized uptake value (SUVmax), MTV and TLG, as markers for differentiating malignant from benign thyroid incidentalomas. RESULTS: Of 99 thyroid incidentalomas, 64 (64.6%) were malignant and 35 (35.4%) were benign. Malignant thyroid incidentalomas were larger (1.8 cm vs. 1.3 cm, p = 0.006), and had higher SUVmax (11.3 vs. 4.8, p 0.05). A threshold TLG 4.0 of 2.475 had 81.3% sensitivity and 94.3% specificity for identifying malignant thyroid incidentalomas. CONCLUSION: Volume-based PET/CT parameters could potentially have clinical value in differential diagnosis of thyroid incidentaloma along with SUVmax.

Relationship Between Dual Time Point FDG PET/CTand Clinical Prognostic Indexes in Patients with High Grade Lymphoma: a Pilot Study / 대한핵의학회잡지

PURPOSE: This study investigated the correlative relationship between metabolic parameters estimated from dual time point 2-deoxy-2-[¹⁸F] fluoro-D-glucose (¹⁸F-FDG) positron emission tomography/computerized tomography (PET/CT) and the clinical tools predicting the outcome of a lymphoma. We also measured metabolic and volumetric alterations between early and delayed ¹⁸F-FDG PET/CT in patients with high grade lymphoma (HGL).METHODS: The samples were 122 lymph nodes and extralymphatic lesions from 26 patients diagnosed with HGL. All patients were applied to the International Prognostic Index (IPI), Ann Arbor stage, and revised IPI as clinical prognostic parameters. ¹⁸F-FDG dual time point PET/ CT (DTPFP) consisted of an early scan 1 h after ¹⁸F-FDG injection and a delayed scan 2 h after the early scan. Based on an analysis of DTPFP, we estimated the standardized uptake value (SUV) of tumors from the early and delayed scans, retention index (RI) representing the percentage change between early and delayed SUV, and metabolic volume different index (MVDI) calculated using metabolic tumor volumes (MTV).RESULTS: RI(max) showed a multiple positive correlative relationship with stage and IPI in lesion-by-lesion analysis (p < 0.01). In the case of IPI, the high risk group exhibited higher RI(max) than the low risk group (p = 0.004). In the case of revised IPI, the RI(max) of the low risk group were significantly lower than the intermediate and high risk groups, respectively (p < 0.01). The MVDIs of the best outcome group were decreased in comparison to the moderate outcome group (p = 0.029). There was a significant negative correlative relationship between RI(max) and MVDI, and the inclinations for decreased MVDIs were slightly associated with increased RIs.CONCLUSIONS: RI(max) extracted from DTPFP had a significant relationship to extranodal involvement, staging, IPI, and revised IPI. MVDI showed significant negative correlation with RI(max). Further large scale studies are warranted to support and extend these preliminary results.

Value of 18F-FDG PET-CT in monitoring recurrence and metastasis of small intestinal adenocarcinoma / 肿瘤研究与临床

Objective To evaluate the clinical value of 18F-FDG PET-CT imaging on monitoring recurrence, metastasis and therapeutic decision-making in small intestinal adenocarcinoma patients after radical surgery. Methods Twenty-two patients were enrolled, who underwent surgical operation before received PET-CT scan. PET-CT findings were retrospectively observed to compare with the results of follow-up [postoperative pathology and (or) long-term clinical follow-up]. The roles of PET-CT on therapeutic decision-making were then investigated. Results Among 22 patients, 14 cases were finally diagnosed as recurrence and (or) metastasis, the other 8 cases as disease-free survival after long-term follow-up. According to PET-CT, 13 cases were diagnosed as recurrence and (or) metastasis (including 12 true-positive and 1 false-positive), and 9 cases were negative (including 2 false-negative). The diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PET-CT were 85.7 % (12/14), 87.5 % (7/8), 86.4 %(19/22), 92.3%(12/13) and 77.8%(7/9), respectively. The therapeutic decisions were changed in 10 patients (10/22, 45.5 % ) based on PET-CT results. Conclusion 18F-FDG PET-CT has an important clinical value on the detection of recurrence and (or) metastasis of small intestinal adenocarcinoma, which is an ideal method of monitoring.

Tomografia por emissão de pósitrons com FDG-18F na avaliação de pacientes com artrite reumatoide - revisão sistemática / Positron emission tomography with 18F-FDG in the evaluation of patients with rheumatoid arthritis - a systematic review

Introdução A artrite reumatoide (AR) é uma doença caracterizada pela inflamação da membrana sinovial. Diversos autores têm investigado o papel da tomografia por emissão de pósitrons (PET) com flúor-18 (FDG-18F) na AR. Objetivos Revisão sistemática da literatura atual sobre o papel do PET com FDG-18F no diagnóstico, determinação da atividade da doença e avaliação da resposta ao tratamento em pacientes com AR. Métodos Foram realizadas buscas nas bases de dados Medline, Biblioteca Cochrane, Lilacs, Pubmed e Scopus nos idiomas português, inglês e espanhol, utilizando as palavras-chave «artrite reumatoide¼, «sinovite¼, «FDG¼, «PET¼, «metabolismo glicolítico¼ e «atividade da doença¼. Resultados 142 artigos foram inicialmente identificados, dos quais apenas 40 relacionavam-se diretamente ao tema. Foram selecionados 12 artigos originais e três relatos de caso que preenchiam os critérios de inclusão. Discussão A presença de fibroblastos e macrófagos ativados no pannus é responsável pela intensa captação periarticular de FDG-18F. Os padrões de captação não permitem o diagnóstico diferencial com outras artrites. A intensidade de captação e o número de articulações envolvidas são parâmetros metabólicos de atividade da doença que apresentam boa correlação com os índices compostos. Estudos longitudinais de PET têm se mostrado úteis na avaliação da resposta ao tratamento com anti-TNF. Quando realizado precocemente, PET pode predizer a resposta terapêutica. Conclusão Embora o real papel dessa nova técnica na investigação da AR ainda não esteja estabelecido, PET com FDG-18F é uma ferramenta ...

Introduction Rheumatoid arthritis (RA) is a disease characterized by inflammation of the synovial membrane. Several authors have investigated the role of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (18F-FDG) in RA. Objectives To systematically review the current literature on the role of 18F-FDG PET in the diagnosis, determination of disease activity and assessment of treatment response in patients with RA. Methods Searches were conducted in Medline, Cochrane Library, Lilacs, Pubmed and Scopus in Portuguese, English and Spanish languages, using the keywords «rheumatoid arthritis¼, «synovitis¼, «FDG¼, «PET¼, «glycolytic metabolism¼ and «disease activity¼. Results One hundred and forty-two articles were initially identified, of which only 40 were related directly to the subject. Twelve original articles and three case reports that met the inclusion criteria were selected. Discussion The presence of activated macrophages and fibroblasts in pannus are responsible for the intense periarticular uptake of 18F-FDG. The uptake patterns do not allow the differential diagnosis with other arthritides. The uptake intensity and the number of joints involved are metabolic parameters of disease activity that correlate well with the composite indices. Longitudinal studies of PET have proven useful in assessing the response to treatment with anti-TNF. When performed early, PET can predict the therapeutic response. Conclusion Although the actual role of this new technique for the investigation of RA is not yet established, 18F-FDG PET is a promising tool in determining the activity and prediction of response to treatment of patients with RA. .

Evaluation of focal thyroid lesions incidentally detected in fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography images.

Background and Purpose: Increased uptake in the thyroid gland (TG) is often identified as an incidental finding on the whole body fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) in non-thyroid cancer patients. Currently, there is no consensus on the appropriate approach for the management of these cases. Thyroid ultrasound, scintigraphy and fine-needle aspiration biopsy (FNAB) are suggested to exclude malignant thyroid lesions. Our aim is to determine the importance of increased F-18-FDG uptake in the TG on positron emission tomography/computed tomography (PET/CT) scans in patients who are being screened for various forms of non-thyroid cancer. Materials and Methods: We evaluated 2000 cases undergoing whole body PET/CT scanning between April 2011 and October 2012. The age, sex, type of primary cancer, maximum standardized uptake value (SUV max ), size of the thyroid nodules and cervical lymph nodes (CLNs) on 18 F-FDG PET/CT images and if available, the biopsy results were evaluated. Results: In total, 57 patients (23 men, 34 women, mean age ± standard deviation (SD), 60.89 ± 14 years) showed an increased fluorine-18-fluorodeoxyglucose ( 18 F-FDG) uptake by the TG (average SUV max : 4.07 ± 3.7). The CLNs were detected in 19/57 patients (33%). Only 20 cases (35%) received FNAB. The final histopathological diagnosis was papillary thyroid carcinoma in seven patients (mean SUV max ± SD: 6.0 ± 5.43) and benign thyroid disease in seven patients (mean SUV max ± SD: 2.36 ± 0.63). The FNAB results were undetermined for six patients. Conclusion: Focal high 18 F-FDG uptake in the TG may be associated with an increased risk of malignancy, but the clinical significance is unclear. More data are needed to elucidate the role of the SUV in the differentiation of benign and malign thyroid lesions. If a focal increase in 18 F-FDG uptake in the TG on PET/CT is present, a prompt histopathological evaluation should be suggested to clinicians for definitive diagnosis.

Muscular Sarcoidosis Detected by F-18 FDG PET/CT in a Hypercalcemic Patient

Sarcoidosis is a systemic granulomatous disease of unknown etiology that involves many organs, occasionally mimicking malignancy. We herein report a 50-yr-old woman of muscular sarcoidosis of chronic myopathic type, manifested by hypercalcemia and muscle wasting. Besides insignificant hilar lymphadenopathy, her sarcoidosis was confined to generalized atrophic muscles and therefore, F-18 FDG PET/CT alone among conventional imaging studies provided diagnostic clues for the non-parathyroid-related hypercalcemia. On follow-up PET/CT during low-dose steroid treatment, FDG uptake in the muscles disappeared whereas that in the hilar lymph nodes remained. PET/CT may be useful in the evaluation of unexpected disease extent and monitoring treatment response in suspected or known sarcoidosis patients.

Avaliação pré-operatória com PET-18F-FDG de nódulos de tireóide com citologia indeterminada / Preoperative evaluation of cytologically indeterminate thyroid nodules with 18F-FDG PET

Esse artigo tem o objetivo de discutir o papel da tomografia por emissão de pósitrons (PET) com 18F-FDG na avaliação pré-operatória de pacientes com nódulos de tireóide com citologia indeterminada. Para o cálculo da sensibilidade, foram selecionados todos os estudos com pacientes com carcinoma de tireóide. Para o cálculo da especificidade, foram selecionados apenas estudos desenhados para avaliação dos pacientes com nódulos com citologia indeterminada. O achado de captação focal na PET-18F-FDG relacionou-se com a presença de carcinoma de tireóide na maioria dos estudos. A sensibilidade do exame foi bastante alta na detecção de malignidade tireoidiana, porém sua especificidade variou de 0 por cento a 66 por cento, sendo de 39 por cento em estudo brasileiro. Concluindo, os estudos indicam que a PET-18F-FDG pode reduzir o número de tireoidectomias desnecessárias em pacientes com nódulos de tireóide com citologia indeterminada. Entretanto, o percentual relativamente elevado de resultados falso-positivos, o alto custo, a baixa disponibilidade do exame em países em desenvolvimento e a pouca experiência clínica ainda limitam o uso da PET-18F-FDG com essa finalidade.

The aim of this article is to discuss the role of 18F-FDG Positron Emission Tomography (PET) in the preoperative evaluation of patients with cytologically indeterminate thyroid nodules. All studies with patients with thyroid cancer were selected to the calculation of sensitivity. Only studies aiming to evaluate patients with thyroid nodules whose cytological result was indeterminate were selected to establish the specificity. The finding of focal 18F-FDG uptake at PET was associated with the presence of thyroid malignancy in most of the studies. The sensitivity of the exam to the detection of thyroid malignancy was extremely high, but the specificity varied from 0 to 66 percent. In our experience, the specificity was 39 percent. In conclusion, the studies suggest that 18F-FDG PET can reduce the number of unnecessary thyroidectomies performed in patients with cytologically indeterminate thyroid nodules. However, the relatively high percentage of false positive results, the high costs, the low availability of this exam in developing countries and the low clinical experience still restrict the use of 18F-FDG PET when recommended with this aim.

A Case with Viral Encephalitis presenting a Dissociations in the Retrograde Amnesia

We describe a case of anterograde and retrograde amnesia resulting from probable herpes simplex encephalitis. In retrograde amnesia, dissociations not only between episodic and semantic memories, but also between semantic memories for personal and public things were observed. We postulated, using FDG-PET, that the former was caused by mesial temporal lesions, based on `multiple trace theory', and the latter, by bilateral lateral temporal lesions, which were probably related to the retrieval of semantic memory, especially for public things.

A Case of Systemic Lupus Erythematosus Presenting with Chorea: Evidence for Striatal Hypermetabolism

Chorea is an uncommon clinical manifestation of Sytemic lupus erythematosus (SLE). Its pathogenic mechanism has not been clearly clarified. We report a 54-year-old woman with SLE who presented with generalized chorea as an initial manifestation. Fluorine-18-fluorodeoxyglucose (FDG) PET revealed increased metabolism in the bilateral putamen. Intravenous and oral administration of steroid markedly improved chorea. Hypermetabolism of the bilateral putamen diminished on follow-up FDG-PET after the disappearance of chorea. This study suggests that chorea in SLE is associated with striatal hypermetabolism.

Correlation of GLUT-1 Expression and F-18-FDG Uptake on Positron Emission Tomography in Breast Carcinoma / 대한암학회지

PURPOSE: Fluorine-18-fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET) has been proven to be useful in the detection of breast cancer. However, the degree of FDG uptake was variable. In this study, we evaluated the relationship between glucose transporter-1 (GLUT-1) expression with the FDG uptake in patients with breast cancer. MATERIALS AND METHODS: 15 patients with proven breast cancer underwent F-18-FDG PET. After surgical resection, anti-GLUT-1 immunohistochemical staining was performed in tumor tissues to measure the GLUT-1 expression. We evaluated the correlation between semi-quantitative FDG uptake by standardized uptake value (SUV) and GLUT-1 expression. RESULTS: In total 15 patients, there was no significant correlation between SUV and GLUT-1 expression. We separated the patients into two groups according to the tumor size. In the group of large tumor (short diameter > or =2 cm), there was no significant correlation. However, in the group of small tumor (short diameter <2 cm), there was a significant correlation between the FDG uptake and GLUT-1 expression (rho=0.812, p=0.047). CONCLUSION: GLUT-1 expression can influence the FDG uptake in the small breast cancers. For large breast cancers, other factors as well as GLUT-1 expression may influence the FDG uptake.