Adenoma hepatocelular con captación de 18 flúor deoxiglucosa en PET-TC SCAN. Una "mini-review" e informe de un nuevo caso / 18-fluoro-deoxyglucose uptake on PET-CT in hepatocellular adenoma. A mini review with a new case Report

RESUMEN La captación de 18 FDG en PET-TC por un adenoma hepatocelular (HCA) es poco frecuente. Esta situación genera dudas en cuanto a los diagnósticos diferenciales y tratamiento. El objetivo de este artículo fue realizar una mini revisión de los últimos 37 años de HCA con avidez por el 18FDG y presentar un nuevo caso. Sobre la base de un estudio realizado por otros autores entre 1984 y 2014, se amplía la búsqueda utilizando las mismas palabras clave hasta el año 2021. Se analizan los datos relevantes. Entre 1984 y 2021 detectamos 38 casos en 37 años. Fue más frecuente en mujeres en edad reproductiva. Los subtipos H-HCA e I-HCA fueron los más frecuentes. El tratamiento quirúrgico fue el más empleado. La diferenciación celular y los trastornos metabólicos de la glucosa y de los lípidos favorecerían la captación de 18FDG. La resección hepática ofrecería mayores garantías permitiendo el estudio completo de la lesión.

ABSTRACT Hepatocellular adenoma (HCA) uptake of 18FDG uptake on PET-CT is rare. This situation poses doubts about the differential diagnoses and treatment. The aim of this article is to perform a mini review of 18FDG avid HCA over the past 37 years and to describe a new case presentation. Based on a study conducted by other authors between 1984 and 2014, we extended the search until 2021 using the same keywords. The relevant data were analyzed. Between 1984 and 2021 we detected 38 cases in 37 years. HCAs were more common in women of childbearing age. The most common types were H-HCA an I-HCA. Surgical resection was the treatment most used. Cell differentiation and glucose and lipid metabolic diseases would favor 18FDG uptake. Liver resection provides better outcomes, allowing for a complete examination of the lesion.

Imaging resemblance but diagnostic disparity in cervix cancer: a rare case report

F-18 FDG PET-CT is an establish modality for staging of cervical cancer. The high uptake value in PET with no evidence of necrosis in CECT is generally understood malignant pathology in known cancer patients. A 47 year-old-female with cervix carcinoma underwent staging FDG PET-CT. It showed FDG avid primary lesion in cervix with FDG avid pelvic, retroperitoneal, mediastinal and supraclavicular lymph nodes. USG guided FNA from the supraclavicular lymph node revealed tuberculosis. Now patient scheduled for ATT and chemotherapy.

Unusual metastatic sex cord stromal tumor - staging and response assessment

Metastatic sex cord stromal tumor (SCST) is rare and contributing <1% of ovarian tumors. A 42-year-old female presented with lower abdominal pain for 2 months. Ultrasonography revealed masses in the abdominal and pelvic. USG guided biopsy from the pelvic mass revealed SCST. For staging, whole body F-18 fluorodeoxyglucose positron emission tomography-computed tomography was performed and revealed heterogenous mildly FDG avid retroperitoneal and bilateral pelvic masses with lung nodules. To confirm the nature of the lung nodule; PET-CT guided biopsy performed and revealed metastatic SCST. After three cycle of chemotherapy, clinical, biochemical and imaging show partial response to treatment.

Primary Pulmonary Primitive Neuroectodermal Tumour: Potential Role of F18-FDG PET/CT as an Imaging Biomarker

@#Primitive neuroectodermal tumours (PNETs) occurring directly from the lung parenchyma without involvement of the chest wall or pleura are particularly unusual. We describe a 16-year-old male who presented with severe chest and back pain following a fall during high jump competition. Incidental finding of an opacity at the right lung upper lobe was seen on his chest radiograph. Computed tomography of the thorax demonstrated a lobulated hypodense lesion in the anterior segment of right upper lobe and subsequent biopsy confirmed the diagnosis of Ewing Sarcoma/ PNET following histologic and immunohistochemical examination. Whole-body positron emission computed tomography/computed tomography (PET/CT) revealed mild, homogenous F18-fluorodeoxyglucose (FDG) uptake in the lung lesion with no evidence of metastasis. He eventually underwent right thoracotomy and right upper lobectomy. Indeed, F18-FDG PET/CT is a valuable imaging method in demonstrating active focus of glucose metabolism in lung parenchymal lesion, for preoperative evaluation and as baseline scan for patient’s monitoring.

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.

Outcome in Patients with Fever of Unknown Origin whose ¹⁸Fluoro-Deoxyglucose Positron Emission Tomography/Computerized Tomography Finding is Non-Diagnostic / 감염과화학요법

Prognosis has not been known for patients with fever of unknown origin (FUO) whose ¹⁸fluoro-deoxyglucose (¹⁸F-FDG) positron emission tomography/computerized tomography (PET/CT) finding is non-diagnostic. A total of eight patients with FUO that underwent ¹⁸F-FDG PET/CT were retrospectively identified January 2016 - June 2017 in a tertiary hospital in Korea. Of these, two patients were diagnosed with microscopic polyangitis and Kikuchi's disease and one patient was transferred to another hospital. Of five patients whose diagnoses were not confirmed, four patients received non-steroidal anti-inflammatory drug and/or low dose steroid and symptoms disappeared. Our study suggests that outcome of patients with FUO whose ¹⁸F-FDG PET/CT finding is non-diagnostic would be favorable.

Outcome in Patients with Fever of Unknown Origin whose ¹⁸Fluoro-Deoxyglucose Positron Emission Tomography/Computerized Tomography Finding is Non-Diagnostic / 감염과화학요법

Prognosis has not been known for patients with fever of unknown origin (FUO) whose ¹⁸fluoro-deoxyglucose (¹⁸F-FDG) positron emission tomography/computerized tomography (PET/CT) finding is non-diagnostic. A total of eight patients with FUO that underwent ¹⁸F-FDG PET/CT were retrospectively identified January 2016 - June 2017 in a tertiary hospital in Korea. Of these, two patients were diagnosed with microscopic polyangitis and Kikuchi's disease and one patient was transferred to another hospital. Of five patients whose diagnoses were not confirmed, four patients received non-steroidal anti-inflammatory drug and/or low dose steroid and symptoms disappeared. Our study suggests that outcome of patients with FUO whose ¹⁸F-FDG PET/CT finding is non-diagnostic would be favorable.

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.

Micro-PET Observation of the Effect of Electroacupuncture on Cerebral Hippocampus Glucose Metabolism in SAMP8 Mice with Senile Dementia / 上海针灸杂志

Objective To observe cerebral hippocampus glucose metabolism using 18F-FDG micro-PET as an imaging technique in a normal group of mice, and model and electroacupuncture groups of SAMP8 mice with senile dementia (rapid aging mice). Method Four 6-month-old SAMR1 mice were picked at random out of the normal group and every four 6-month-old SAMP8 mice, out of the model and electroacupuncture groups respectively. Each of them was anesthetized by inhalation of 2% isoflurane and then given a bolus injection of radioactive tracer 18F-FDG 14.8~16.5 MBq through the tail vein. After one hour of the uptake, a PET scan was performed for 10 min. Hippocampus 18F-FDG uptake rate per gram of brain was calculated in every group of mice and the uptake rates were compared between the groups.Result The 18F-FDG uptake rate per gram of brain tissue was higher in the electroacupuncture group of mice than in the normal and model groups.Conclusion Electroacupuncture can markedly increase cerebral 18F-FDG uptake and the uptake rate per gram of brain tissue in SAMP8 mice. It may play a neuroprotective role through its influence on cerebral glucose metabolism.

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.

Tuberculous Scar Tumour Detected by Dual Tracer Positron Emission-Computerised Tomography in a Tuberculous Endemic Area

Tuberculous scar tumour is difficult to diagnose as it does not present with any respiratory symptoms and has a negative chest X-ray. This is a case report on the use of dual tracer 11C-acetate and 18F-fluorodeoxyglucose (18FDG) whole body positron emission tomography-computerised tomography (PET-CT) for detection of tuberculous scar tumour. A 44-year-old Chinese female was incidentally found to have a raised serum Ca 19.9. Magnetic resonance imaging of the whole abdomen, upper endoscopy, and colonoscopy were all unremarkable. A low-dose computed tomography (CT) of the thorax showed bilateral upper lobe fibrosis. Bronchoalveolar lavage for culture and cytology was negative. A dual tracer 11C-acetate and 18FDG whole body PET-CT showed that the left upper lobe fibrosis was hypermetabolic in nature. It was more avid for 11C-acetate than for 18FDG. The left upper lobe lesion was subsequently confirmed on open lung biopsy to be a moderately differentiated adenocarcinoma. Therefore, in a tuberculous endemic region, dual tracer whole body PET-CT with 11C-acetate and 18FDG may have a role in the early detection of tuberculous scar tumour in the lung.

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.

Determinación de actividad inflamatoria en pacientes con arteritis de Takayasu mediante tomografía por emisión de positrones (PET) / PET evaluation of inflammatory process in Takayasu's arteritis

Objetivos: Determinar la aplicación que tiene la tomografía por emisión de positrones en el seguimiento de pacientes con arteritis de Takayasu con actividad inflamatoria y su correlación con los criterios clínicos establecidos. Métodos: Se incluyeron 35 pacientes con diagnóstico de arteritis de Takayasu. Se determinó velocidad de sedimentación globular, proteína C reactiva, biometría hemática, así como, fibrinógeno y se aplicaron los criterios clínicos de actividad. Se realizó tomografía por emisión de positrones basal de los pacientes positivos para actividad inflamatoria, todos recibieron tratamiento farmacológico. De forma aleatoria se incluyó a 10 pacientes que posterior al tratamiento durante seis meses se les realizó un nuevo estudio clínico y una tomografía por emisión de positrones para determinar actividad inflamatoria. Se compararon los criterios clínicos con tomografía por emisión de positrones tanto del estudio basal como el de seguimiento. Resultados: Los criterios clínicos tuvieron una sensibilidad de 63% y especificidad de 90% para demostrar actividad inflamatoria en forma basal. La sensibilidad de los criterios clínicos disminuyó posterior al tratamiento hasta 27%, en donde se observó que pacientes aparentemente inactivos por clínica, continuaban activos por tomografía por emisión de positrones. Discusión: Éste es el primer estudio que compara de manera prospectiva los hallazgos de tomografía por emisión de positrones antes y después del tratamiento para actividad inflamatoria en pacientes con arteritis de Takayasu. Los criterios clínicos carecen de sensibilidad para la detección de actividad inflamatoria en el seguimiento posterior al tratamiento. Conclusiones: El tomografía por emisión de positrones es una técnica de diagnóstico con una alta sensibilidad y especificidad para el diagnóstico y seguimiento de pacientes con arteritis de Takayasu y actividad inflamatoria.

Objective: To determine the application of PET in monitoring patients with Takayasu's arteritis (TA) with inflammatory activity (IA) and its correlation with established clinical criteria. Methods: 35 patients diagnosed with TA were enrolled. Determination of erythrocyte sedimentation rate, C-reactive protein, fibrinogen and a complete blood count was performed and clinical criteria of activity were applied. A baseline PET was performed in all patients. Those who were positive for IA received drug treatment. Among the group of active patients, ten were randomized to undergo another PET scan and clinical criteria determination to evaluate inflammatory activity after 6 months of treatment. We compared clinical criteria with PET capacity to determine IA. The results between the initial and final PET were finally compared. Results: Clinical criteria had a sensitivity of 63% and a specificity of 90% to show IA. Sensitivity decreased after 6 months of treatment to 27%. Discussion: This is the first prospective study that compares the findings of PET before and after treatment for IA in patients with TA. Clinical criteria lack sensitivity for the detection of IA in the follow-up after treatment. Conclusions: PET is a diagnostic technique with high sensitivity and specificity for the diagnosis and monitoring of patients with TA and inflammatory activity.

Primary Malignant Peritoneal Mesothelioma Mimicking Peritoneal Carcinomatosis on F-18 FDG PET/CT / 핵의학분자영상

Malignant mesothelioma of the peritoneum is a rare neoplasm with a rapidly fatal course. The tumour arises from the mesothelial cells lining the pleura and peritoneum or, rarely, in the pericardium or tunica vaginalis. This neoplasm is characterized by being difficult to diagnose, having a rapid evolution and a poor response to therapy. Mesothelioma is very glucose avid, and malignant pleural mesothelioma has been reported concerning the utility of F-18 FDG PET or PET/CT. But little has been known about the imaging finding of malignant peritoneal mesothelioma on F-18 FDG PET/CT. We report a case of malignant peritoneal mesothelioma mimicking peritoneal carcinomatosis of F-18 FDG PET/CT.

A Neurofibroma Confused with Sarcomatous Transformation on F-18 FDG PET/CT in Neurofibromatosis-1 / 핵의학분자영상

We present a patient with high 18F-fluorodeoxyglucose (FDG) uptake detected in a neurofibroma that was confused with sarcomatous transformation on a positron emission tomography/computed tomography (PET/CT) scan. A 39-year-old male patient with a 20-year history of neurofibromatosis-1 (NF-1) performed FDG PET/CT scan for the evaluation of lesions with sarcomatous transformation. The FDG PET/CT images demonstrated varying degrees of increased FDG uptake in the multiple nodules throughout whole body. The left pelvic mass with the highest FDG uptake had a maximum standardized uptake values (maxSUV) 5.0 and surgical resection was performed. Histological analysis confirmed the presence of a benign neurofibroma infiltrated with inflammatory cells.

Sequential Change of Hypometabolic Metastasis from Non-small-cell Lung Cancer on Brain FDG-PET/CT / 핵의학분자영상

A 60-year-old woman, who had non-small-cell lung cancer (NSCLC) in left lower lobe underwent brain F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for evaluation of cerebral metastasis. On follow-up FDG-PET/CT, only hypometaolic lesion was detected and progressed in right frontal lobe at 6 months and 10 months, later. Hypermetabolic metastasis was not detected even at last scan time of FDG-PET/CT. Brain MRI showed brain metastasis in right frontal lobe. As might be expected, the physician should take cerebral metastasis into consideration even though there is only hypometabolic change on subsequent FDG-PET/CT in patients with NSCLC.

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.

The role of Positron Emission Tomography in hepatobiliary cancers / 한양의대학술지

Imaging approach for early diagnosis, accurate staging, and the evaluation of treatment response has been consisted of anatomical and functional imaging methods. The anatomical image usually depends on high spatial resolution to distinguish morphological difference from normal anatomy, but altered anatomy is not a specific finding for malignancy. Moreover, it frequently needs other imaging modalities for systemic evaluation of disease. The functional image has been used for research and clinical purpose to overcome these shortcomings of the anatomical image, and the importance of functional evaluation of tumors is widely accepted by the introduction of Positron Emission Tomography (PET). Most of the PET systems at present are supplied as PET/CT combining functional and anatomical images, altogether. Especially for hepatobiliary tumors, showing a low sensitivity by PET alone, PET/CT will play an important role in determining TNM stage, deciding treatment modality, and evaluating treatment response. In addition, PET/CT as the most advanced molecular image technique has further growing potentials such as the development of a faster PET system, various new PET tracers, etc, which will contribute to improving patient survival and the quality of life.