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Está establecida en la literatura la utilidad de la tomografía por emisión de positrones (PET) con 18F-flúordeoxiglucosa (FDG) en la etapificación, reetapificación y seguimiento del melanoma maligno. Objetivo: Evaluar los resultados del PET FDG en melanoma maligno en nuestro centro. Material y Método: Entre febrero 2003 y julio 2004, se estudiaron 33 pacientes (edad 49±14 años, 52% sexo masculino) referidos para etapificación y reetapificación de melanoma maligno. El examen fue realizado en equipo de alta resolución Siemens Ecat Exact HR+ con dosis de 13±3 mCi de FDG y glicemias en ayunas preinyección de 96±16 mg/dL. Se adquirieron imágenes de cuerpo entero, incluyendo cabeza y extremidades inferiores. El informe se basó en el análisis visual e índice cuantitativo de captación (SUV). Se comparó con otros estudios de imágenes e histología cuando estaban disponibles y se realizó seguimiento clínico. Resultados: Nueve pacientes fueron derivados para etapificación y 24 para reetapificación. En 29 casos, la localización inicial del primario era conocida y en 4 la enfermedad se diagnosticó por la presencia de metástasis ganglionares. Respecto de la localización tumoral, 6 fueron en cabeza y cuello (2 metástasis ganglionares), 5 en coroides, 5 en tronco, 5 en extremidades superiores, 11 en extremidades inferiores y 1 en mucosa (rectal). En 13 pacientes, el PET fue positivo para presencia de actividad tumoral hipermetabólica, 7 en ubicación próxima al primario y 6 alejados de éste, correspondiendo uno de estos últimos a un segundo primario (carcinoma rectal confirmado con histología). De este grupo, en 11 pacientes se confirmó tumor: en 7 hubo confirmación histológica postcirugía y en los restantes, hubo concordancia con imágenes anatómicas y clínica (1 paciente falleció); además, el PET demostró lesiones no sospechadas por otros estudios, las que no han sido confirmadas con histología. Dos fueron falsos positivos, uno por hematoma y otro por ...
Background: The usefulness of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) for the staging and follow up of malignant melanoma, is well established. Aim: To assess the results of PET FDG in patients with malignant melanoma. Patients and Methods: Thirty three patients with malignant melanoma (aged 49 ± 14 years, 17 males), referred for staging and restaging, were studied. The tomography was performed using a Siemens Ecat Exat high resolution equipment. The dose of FDG was 13 ± 3 mCi and the blood glucose levels prior to injection were 96 ± 16 mg/dl. Whole body images, including the head and legs were acquired. The report was based on the visual analysis and standardized uptake value (SUV). Results: Nine patients were referred for staging and 24 for restaging. The location of the primary tumor was known in 29 cases and in four, the disease was diagnosed due to the presence of lymph node metastases. The tumor was located in the head and neck in six patients (including two lymph node metastases), in the choroid in five, in the trunk in five, in the superior limbs in five, in the inferior limbs in 11 and in the rectal mucosa in one. In 13 patients, PET was positive for the presence of hypermetabolic tumor activity. In seven, the location was near the primary tumor and in six, it was distant. In seven patients the presence of tumor was confirmed by surgery and in four, there was concordance between the anatomical imaging and clinical outcome. Two false positive images were detected, one hematoma and one due to the presence of lymph node inflammation. In 16 cases, PET was negative and in four it was not conclusive, all these patients do not have evidence of tumor in the clinical follow up. The primary location of the tumor was not identified in patients referred for lymph node metastases. Conclusions: FDG PET is useful for the staging and re staging of patients with malignant melanoma.
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UNLABELLED: Coronary angiography is the "gold standard" for the diagnosis of coronary artery disease (CAD). The aim of this work was to compare 201Thallium SPECT with different coronary angiographic cutoff values. METHODS: Data pertaining to 145 patients were tabulated. All patients underwent stress ECG, 201Thallium SPECT and coronary angiography. To assess the cutoff impact, two criteria for coronary angiography diagnosis were used: a) > or = 50% and b) > or = 75% stenosis, and applied to data from patients and vessels. RESULTS: On a patient basis, 201Thallium SPECT sensitivity, specificity and accuracy were 87%, 57% and 81% with > or = 50% cutoff and 93%, 51% and 79% with > or = 75% cutoff, respectively (NS). When performing individual vessel analysis, sensitivity, specificity and accuracy were 59%, 78% and 68% for > or = 50% cutoff and 70%, 75% and 74% for > or = 75% cutoff, respectively (p < 0.029 for sensitivity). As expected, the severer the stenosis the higher the detection rate. There were 19 patients who had stenosis between 50% and 74%. Of these, 21% had abnormal stress ECG and 58% abnormal Thallium-201 SPECT. CONCLUSION: 201Thallium SPECT results support the use of > or = 50% stenosis cutoff criteria for CAD diagnosis and evaluation. Combined with coronary angiography, myocardial SPECT offers an excellent management strategy to patients.