Lilian Yuri Itaya Yamaga

The effect of catecholamines on the glucose uptake in brown adipose tissue demonstrated by 18F-FDG PET/CT in a patient with adrenal pheochromocytoma

A 50-year-old man had the diagnosis of right adrenal pheochromocytoma made by computed tomography (CT) scan together with the evidence of raised plasma catecholamine and urinary catecholamine metabolite levels. A positron emission tomography (PET)/CT study with Ffluorodeoxyglucose (FDG) demonstrated intense, bilateral, and symmetric uptake in brown adipose tissue (BAT) in the neck, supraclavicular, axillary, mediastinal, paravertebral, and perinephric regions and also in the right adrenal gland (a, arrows). Histologic examination of the excised tumor demonstrated a typical presentation of pheochromocytoma. Five days after the surgery, another PET/CT scan showed no uptake in BAT. A slight uptake was seen in the right adrenal bed which was attributed to an inflammatory process (b, arrow). Symmetrically increased F-FDG uptake occurring in areas of fat of the neck, supraclavicular, paravertebral, mediastinal, and perinephric regions has been described with F-FDG PET/CT [1]. Brown fat has the ability to increase its blood flow with norepinephrine stimulation and is rich in adrenergic innervation [2]. Glucose uptake increases when the BAT sympathetic nervous system is activated [3, 4]. Although BAT is more

The role of gallium-67 scan in defining the extent of disease in an endemic deep mycosis, paracoccidioidomycosis: a predominantly multifocal disease

The tools currently used to evaluate the extent of paracoccidioidomycosis (PCM) may be of limited value in detecting subclinical lesions. The aim of this study was to verify the role of gallium-67 whole-body scan in evaluating the extent of disease of 65 patients with active PCM. The 67Ga scan findings were compared with the results of clinical evaluation, chest radiography and/or high-resolution computed tomography (CT), abdominal ultrasound (US) or CT, laryngoscopy, CT or magnetic resonance imaging (MRI) of the head, and technetium-99m methylene diphosphonate bone scan, obtained before treatment. Clinically unsuspected lesions were detected by imaging procedures in 21 patients (32%), mainly in the lungs (n=11), adrenals (n=6), and superficial (n=3) and deep lymph nodes (n=14). 67Ga scan detected 100% of the cases with subclinical involvement in the lungs. Scintigraphy was superior to chest radiography in demonstrating lung disease (94% vs 81%). The lymphatic lesions were demonstrated by 67Ga scan in all the clinically suspected cases and in nearly all unsuspected cases, and also revealed more extensive involvement than was clinically suspected in many of them. There was good agreement between 67Ga scan and the other imaging procedures for the initial detection of thoracic and abdominal lymph nodes and bone involvement. 67Ga imaging detected most cases of laryngopharyngeal disease with active inflammatory lesions found at indirect laryngoscopy. On the other hand, 67Ga scan failed to demonstrate most of the adrenal and CNS lesions detected by abdominal US/CT and head CT/MRI. In conclusion, 67Ga imaging is a useful tool for evaluating the location and extent of suspected and unsuspected lesions in PCM. It could serve as a screening method before the use of other diagnostic procedures, particularly in the detection of lung, superficial and deep lymph node and bone involvement.

F-18 FDG PET/CT imaging in small cell prostate cancer.

Abstract: Positron emission tomography/computed tomography scan with F-18 fluorodeoxyglucose was performed in a 77-year-old patient with prostatic adenocarcinoma treated with hormonal therapy, who presented 2 years later with an abdominal mass and slowly increasing prostate specific antigen and carcinoembryonic antigen. Positron emission tomography-computed tomography scan showed intense uptake of F-18 fluorodeoxyglucose in the prostate tumor, iliac, and periaortic lymph nodes and also in a focal area in the right lobe of the liver. The new biopsy of the tumor and lymph nodes was compatible with small cell prostate cancer.

Valor diagnóstico da tomografia por emissão de pósitrons / tomografia computadorizada (PET-CT) com flúor-18 fluordeoxiglicose (FDG-18F) em pacientes com carcinoma diferenciado da tireóide, níveis séricos de tireoglobulina elevados e pesquisa de corpo inteiro com iodo negativa

PURPOSE To evaluate the role of PET-CT with FDG-18F in the detection of recurrence and/or metastasis of differentiated thyroid carcinoma (DTC) in patients with elevated levels of thyroglobulin (TG) and negative whole body scan (WBS). PATIENTS AND METHOD PET-CT findings of 25 patients were compared to histopathology evaluation and conventional imaging (CI). RESULTS PET-CT scan was positive in 16 patients finding 14 true-positive and 2 false-positive cases (positive predictive value 87.5%). Nine patients had negative PET-CT; two had decrease of TG to undetectable levels. One patient had residual disease detected by post-therapeutic WBS. Six patients had no evidence of tumor during follow-up (mean time 16 months). PET-CT was concordant with CI in 52%, partially concordant in 12% and discordant in 36% (6 false-negatives and 3 false-positive of CI). We observed a tendency of increasing proportion of positive PET-CT with increasing TG. CONCLUSION PET-CT scan with FDG-18F is useful in the detection of recurrence and/or metastases of DTC with high TG levels but negative WBS. It presents elevated positive predictive value and is superior to CI being more effective as higher the serum TG levels.

THE COMBINED USE OF CALCITONIN DOUBLING TIME AND 18F-FDG PET/CT IMPROVES PROGNOSTIC VALUES IN MEDULLARY THYROID CARCINOMA: THE CLINICAL UTILITY OF 18F-FDG PET/CT

OBJECTIVE Calcitonin and carcinoembryonic antigen (CEA) doubling times are established prognostic markers in medullary thyroid cancer (MTC). On the other hand, 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) shows an increased rate of detection with high blood tumor marker levels in several cancers. This study aimed to analyze the ability of 18F-FDG PET/CT to determine prognosis in the follow-up of patients with MTC. METHODS Medical records of 17 patients with MTC who underwent 18F-FDG PET/CT were analyzed retrospectively. All patients were classified into two groups: stable disease or progressive disease. RESULTS Eight patients presented with progressive disease, and all of them showed 18F-FDG uptake (100%), compared to only 3 of 9 patients who presented in stable condition (33%). 18F-FDG PET/CT results were able to distinguish progressive from stable disease (P = .009). Calcitonin levels >4,020 pg/mL (P = .0004), CEA levels >26.8 ng/mL (P = .04), and a calcitonin doubling time <24.1 months (P = .015) were associated with progressive disease in our cohort. The proportion of variance explained that predicted progressive disease was 32% for 18F-FDG uptake, 27.1% for a calcitonin doubling time of 24.1 months, and 41.2% for doubling time plus 18F-FDG PET/CT. CONCLUSION 18F-FDG uptake was able to distinguish progressive from stable disease. However, this tool should not replace the validated calcitonin doubling time, but rather the combination of information could improve the clinical re-assessment and better identify high-risk patients who require more careful surveillance. ABBREVIATIONS CEA = carcinoembryonic antigen CT = computed tomography 18F-FDG = 18F-fluorodeoxyglucose MTC = medullary thyroid cancer PET = positron emission tomography PVE = proportion of variance explained sCT = serum calcitonin SUV = standard uptake value US = ultrasound.

PET-CT as an Alternative to Fiducial Markers Guidance in Liver Metastasis Treatment

The liver is the organ most commonly affected by colorectal cancer metastasis. Currently, liver resection is the treatment of choice, but in cases where it is not possible, intensity-modulated radiation therapy is an alternative. We report the case of a 57-year-old woman whose colorectal carcinoma metastasized to the liver. She was referred for implantation of fiducial markers for intensity-modulated radiation therapy planning. PET-CT stands out as an additional tool for distinguishing metabolically active tumor tissue from other tissues, ensuring effective introduction of percutaneous fiducial markers, especially in cases where use of conventional imaging techniques is limited.

Normalization of lymphocyte count after high ablative dose of I-131 in a patient with chronic lymphoid leukemia and secondary papillary carcinoma of the thyroid. Case report

ABSTRACT The authors report the case of a 70-year-old male patient with chronic lymphoid leukemia who presented subsequently a papillary carcinoma of the thyroid with metastases to regional lymph nodes. The patient was treated with surgical thyroidectomy with regional and cervical lymph node excision and radioiodine therapy (I-131). The protocolar control scintigraphy 4 days after the radioactive dose showed I-131 uptake in both axillae and even in the inguinal regions. PET/CT showed faint FDG-F-18 uptake in one lymph node of the left axilla. An ultrasound guided fine needle biopsy of this lymph node identified by I-131 SPECT/CT and FDG-F-18 PET/CT revealed lymphoma cells and was negative for thyroid tissue and thyroglobulin content. The sequential blood counts done routinely after radiation treatment showed a marked fall until return to normal values of leucocytes and lymphocytes (absolute and relative), which were still normal in the last control 19 months after the radioiodine administration. Chest computed tomography showed a decrease in size of axillary and paraaortic lymph nodes. By immunohistochemistry, cells of the lymphoid B lineage decreased from 52% before radioiodine therapy to 5% after the procedure. The authors speculate about a possible sodium iodide symporter expression by the cells of this lymphoma, similar to some other non-thyroid tumors, such as breast cancer cells.

Estudo comparativo da qualidade de imagem dos modos de aquisição da PET: validação de um protocolo para reduzir a dose de radiação

OBJECTIVE: The present study is aimed at validating a 3D acquisition protocol for positron emission tomography as a replacement for the 2D mode, to reduce the radiation dose delivered to patients, without any loss in the quality of images. MATERIALS AND METHODS: The study comprised 27 simulations in a Discovery ST equipment with four-minute 2D acquisitions, and two-minute and four-minute 3D acquisitions, utilizing a chest phantom according to the National Electrical Manufacturers Association protocol. Six spheres with different diameters were inserted into this phantom as a means for determining the images quality. The images were blindly reviewed by three experienced nuclear physicians who did not know the acquisition modes. Each observer attributed a score 1 when one of the spheres was not identified, or 2 for visible spheres. RESULTS: The qualitative analysis based on generalized kappa coefficient demonstrated that the frequency of visible spheres was higher with four-minute 3D acquisitions (85%), with an also higher interobserver agreement (88.9%), generalized kappa = 0.725 [0.507;0.942]. CONCLUSION: The protocol with four-minute 3D acquisition with lower 18F-FDG activity can be utilized for patients with a biotype similar to the phantom, without any loss in the imaging quality.

Recorrência em pacientes portadores de melanoma cutâneo submetidos a biópsia de linfonodo sentinela: seguimento mediano de 37 meses

OBJETIVO: A biopsia de linfonodo sentinela (BLS) representa um avanco na cirurgia oncologica para o microestadiamento do melanoma. Apresentamos nossa experiencia dando enfase para a recorrencia. METODO: A BLS foi realizada em 133 pacientes portadores de melanoma cutâneo localizado envolvendo linfocintilografia, mapeamento linfatico e deteccao gama intra-operatorios em todos os pacientes. O exame histopatologico foi realizado por HE e imunohistoquimica (IHC). RESULTADOS: Encontrou-se LS em 128 pacientes (96,2%). Micrometastase foi diagnosticada em 20 pacientes (15,6%). Houve nove recorrencias, sendo quatro no grupo com LS negativo (108 pacientes). Neste grupo, houve uma recorrencia sistemica e tres (2,8%) na regiao linfatica de drenagem (falso negativo). No grupo com LS positivo (20 pacientes) ocorreram cinco recorrencias. Houve diferenca significativa de recorrencia entre os grupos, tendo sido menor no grupo LS negativo (p=0,0048). Atraves de analise de regressao logistica univariada a ulceracao (p=0,029) e a positividade do LS (p=0,003) apresentaram significância estatistica como fatores de risco. Porem, apenas a positividade do LS manteve singificância na analise multivariada (p=0,024). O seguimento mediano foi de 37 meses. CONCLUSOES: Pacientes com LS positivo apresentam recorrencia significativamente maior que pacientes com LS negativo. O indice de falso negativo foi de 2,8% e os pacientes nao apresentaram sequelas o que permite considerar a BLS como procedimento seguro para o microestadiamento do melanoma cutâneo.