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OBJECTIVE: Extracardiac activity (ECA) may affect interpretation of gated SPECT myocardial perfusion studies (MPSs). To solve this problem, available softwares include myocardial edge delimitation. PURPOSE: To evaluate the influence of ECA in automatic myocardial edge detection under normal conditions and with abnormal perfusion and also evaluate the reproducibility of semi-automatic processing. METHODS: A total of 100 MPSs, 50 with ECA, were analyzed. Each subgroup included 25 cases with perfusion abnormalities. The cases were processed automatically and by 4 independent operators with different levels of experience. Commercial QGS and QPS softwares were used with tools to mask and relocate the left ventricle area. Functional parameters (final diastolic and systolic volumes and ejection fraction) and perfusion parameters such as the reversibility perfusion score and rest perfusion defect extension were analyzed. The data were compared with Pearson's correlation and Student's test. RESULTS: Interobserver correlation significantly worsened with the presence of ECA and was moderately affected by perfusion abnormalities. More experienced observers presented better correlation. Reproducibility was greater for the functional perfusion parameters, independently of the observer's experience. CONCLUSIONS: ECA significantly affects automatic edging delimitation, affecting the MPS values. Interobserver reproducibility with manual processing was more altered regarding functional parameters than in the perfusion scores. Perfusion abnormalities did not interfere with software reproducibility, and when present, better correlation was found. If ECA is not present, manual intervention should be avoided.
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Artefatos , Tomografia Computadorizada por Emissão de Fóton Único de Sincronização Cardíaca , Isquemia Miocárdica/diagnóstico por imagem , Imagem de Perfusão do Miocárdio , Variações Dependentes do Observador , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Sestamibi , Idoso , Automação , Feminino , Humanos , Intestinos/diagnóstico por imagem , Fígado/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/patologia , Compostos Radiofarmacêuticos/farmacocinética , Reprodutibilidade dos Testes , Software , Volume Sistólico , Tecnécio Tc 99m Sestamibi/farmacocinética , Radioisótopos de Tálio/farmacocinética , Distribuição TecidualRESUMO
UNLABELLED: Coronary artery disease (CAD) is the leading cause of death in many countries. Stress electrocardiogram (ECG) is able to detect myocardial ischemia and also has prognostic value, which may be impaired in presence of electrical baseline abnormalities. Stress myocardial single photon emission tomography (SPECT) has recognized utility yield in assessment of CAD, requiring independent interpretation of ECG and myocardial images. PURPOSE: To analyze stress ECG interpretation reproducibility among observers with different training level, including pre- and post-graduate medical students, compared to an experienced cardiologist and also with SPECT. METHOD: We studied 95 patients under CAD evaluation, mean age 61+/-9.3 years (range: 42-85), 56% male. Interobserver correlation kappa (k) between perfusion gated (99m)Tc-Sestamibi SPECT and exercise ECG were calculated as normal/abnormal, presence of necrosis, ischemia or mixed pattern. Interobserver kappa (k) analysis was made. RESULTS: 49.5% stress ECG and 45% SPECT studies were abnormal at the initial report with 62.1% concordance (k: 0.24) for normal/abnormal and 58.9% for ischemia (k: 0.14). Agreement between stress ECG initial report and independent cardiologist was 89.5% (k: 0.78). The correlation between independent observers and the initial report ranged between 62.1% and 48.4%, for baseline ECG between 41.1% and 90.5% considering normal/abnormal, and between 80% and 93.7% (k: 0.59-0.87) for the presence of ischemia. CONCLUSION: Stress ECG interpretation presented adequate interobserver reproducibility with greater agreement in the most experienced observers, confirming the importance of training.
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Doença das Coronárias/diagnóstico por imagem , Teste de Esforço , Imagem de Perfusão do Miocárdio , Variações Dependentes do Observador , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Idoso , Idoso de 80 Anos ou mais , Cardiologia/educação , Competência Clínica , Eletrocardiografia , Feminino , Imagem do Acúmulo Cardíaco de Comporta , Humanos , Masculino , Pessoa de Meia-Idade , Medicina Nuclear/educação , Médicos/psicologia , Reprodutibilidade dos Testes , Método Simples-Cego , Estudantes de Medicina/psicologiaRESUMO
INTRODUCTION AND OBJECTIVES: The correct interpretation of myocardial perfusion single photon emission computed tomography (SPECT) requires knowledge of the technique reproducibility. The objective was analyze the interobserver correlation of different experience in the interpretation of myocardial perfusion SPECT in patients following acute myocardial infarction (AMI) in order to improve the quality of our site. METHODS: Sixty cases (56 +/- 11 years, 87 % men) with transmural AMI who had recently undergone successful thrombolysis were included. Resting perfusion with (99m)Tc-sestamibi was performed at one week post-AMI. ANALYSIS: Semiquantitative interpretation using 17 segment-model by 2 independent specialists and 5 observers, was performed blindly. Left ventricular ejection fraction (LVEF) was measured with isotopic ventriculography one month after AMI, with a mean of 38 %. RESULTS: Using independent and then agreed on perfusion analysis, average involved segments/patient was 9.3 +/- 4 and the sum of severity 25 +/- 13. Readings of other observers ranged from 7 +/- 3.7 to 9.4 +/- 3.9 and 16.7 +/- 9.7 to 24.6 +/- 13, respectively, consistent with the reading of the specialists of between 0.779-0.871 (kappa: 0.565-0.741). There was no significant difference when the number of segments were analyzed in 40 % of the cases and for intensity in 60 % of them in more experienced observers. Correlation with consensus reading for the number of segments ranged from 0.84 to 0.94 and for severity from 0.79 to 0.89. Identification of culprit arteries was acceptable, with r values between 0.612 and 0.683 and kappas between 0.629 and 0.656. Correlation of the number of involved segments and severity with LVEF performed one month after AMI was 0.73 and 0.74, respectively. CONCLUSIONS: There was good correlation in the interpretation of myocardial perfusion SPECT, with a significantly better fit in more experienced observers. This academic exercise was also helpful in improving our residents' skills in cardiology.
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Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/cirurgia , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Sestamibi , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reperfusão Miocárdica , Variações Dependentes do ObservadorRESUMO
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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Introducción: El diagnóstico y etapificación de pacientes portadores de lesiones pulmonares con PET-FDG permite optimizar el manejo y seleccionar la terapia más adecuada para cada uno. Objetivo: Analizar nuestra experiencia preliminar con PET-FDG en la caracterización metabólica de nódulos o masas pulmonares, correlacionándolo con histología cuando estaba disponible y evaluando el impacto en la conducta terapéutica. Material y Método: Se analizaron 58 pacientes referidos para evaluación de nódulo o masa pulmonar (62±7 años de edad; 48% sexo masculino; 40% fumadores). Los PET se realizaron en ayunas, utilizando 13 mCi de FDG-F18, con glicemia preinyección de 101± 5 mg/dl. Se adquirieron imágenes de cuerpo entero con análisis visual de cortes coronales, sagitales y transaxiales e imágenes 3D, así como análisis cuantitativo del índice de captación estandarizada SUV. Los estudios se compararon con histología y seguimiento clínico. Resultados: En 22 pacientes (38%), las lesiones pulmonares fueron hipermetabólicas y en 64%, no hubo evidencias de actividad tumoral. En 24% de los pacientes, se encontraron además lesiones extrapulmonares no sospechadas por otras técnicas de imágenes. El rango de tamaño de los nódulos/masas pulmonares era de 0,5 a 7 cm; en el grupo de PET positivo, el tamaño era mayor a 0,8 cm. Se obtuvo histología en 16/58: en 12 de ellos, se confirmó la presencia de neoplasia (75%), correspondiendo la mayoría a adenocarcinoma. Dos pacientes fueron falsos positivos, demostrándose en uno, un schwanoma abscedado y en el otro, un hamartoma. En 2 pacientes con nódulos sin actividad hipermetabólica al PET (estudio normal), sometidos a cirugía por las características del nódulo al TC, se corroboraron lesiones benignas. En los restantes pacientes con lesiones negativas, el seguimiento clínico no ha demostrado eventos hasta la fecha. Un paciente referido por nódulo pulmonar no fue incluido en el análisis debido a que en el PET presentaba ...
Background: The diagnosis and staging of pulmonary lesions with positron emission tomography (PET) with 18fluorodeoxyglucose (FDG) helps in the selection of the optimal therapy. Aim: To analyze the usefulness of FDG PET in the characterization of pulmonary nodules. Patients and Methods: Fifty eight patients referred for the assessment of a pulmonary nodule or mass (aged 62 ± 7 years, 28 males, 40% smokers), were studied. The imaging study was perfomed in the fasting state injecting 13 mCi of 18FDG. Pre injection blood glucose was 101 ± 5 mg/dl. Whole body images were acquired with visual analysis of coronal, sagittal and trans axial slices and three dimensional images. The standardized uptake value (SUV) was also calculated. Results: Pulmonary lesions were hypermetabolic in 22 patients (38%) and in the rest, there was no evidence of tumor activity. Extrapulmonary lesions were detected in 24% of patients. The size of the nodules ranged from 0.5 to 7 cm. in diameter. Those with positive PET had lesions over 0.8 cm diameter. In 12 of 16 patients with pathological study, the presence of cancer was confirmed. Two patients had false positive images. One had an abscessed Schwanoma and the other, a hamartoma. Two patients with PET images not suspicious of tumor, were operated and the pathology confirmed the absence of cancer. In the rest of patients with a negative study, the clinical follow up has been uneventful. In one patient with multiple hypermetabolic lesions with a pattern suggestive of sarcoidosis, the diagnosis was pathologically confirmed. Conclusions: FDG PET is useful for the characterization of pulmonary lesions and nodules.
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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.
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Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Estenose Coronária/diagnóstico por imagem , Radioisótopos de Tálio , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
La pesquisa adecuada del tromboembolismo pulmonar (TEP) tiene importancia en el manejo terapéutico y en el pronóstico de los pacientes. El cintigrama de ventilación y perfusión (VQ) es un método bien establecido en la evaluación de esta patología. La concordancia interobservador puede ser bastante variable y debieran minimizarse las discordancias dentro de un mismo grupo. Objetivo: Conocer la concordancia entre observadores formados en nuestro centro y correlacionarlos con el informe oficial emitido con los antecedentes clínicos y radiológicos. Método: Se analizaron retrospectivamente 401 estudios de 382 pacientes con sospecha de TEP de diferente probabilidad clínica, informados por 6 observadores independientes con distinta experiencia. Se realizó lectura en forma ciega informando como alta, baja o intermedia probabilidad de TEP, basado en la experiencia individual y en criterios PIOPED modificados. Se aplicó kappa ponderado. Resultados: En los informes existió 27.2 por ciento de alta probabilidad de TEP, 5.5 por ciento fueron intermedia o indeterminada y 67.3 por ciento de baja probabilidad, casi normal o normal. La concordancia entre los observadores varió entre 72.6 y 86 por ciento con variación de índice kappa entre 0.582 y 0.743. La correlación con el informe emitido varió entre 74.3 y 81.8 por ciento y (k: 0.582 y 0.675). Hubo mayor concordancia entre los observadores con mayor experiencia. Conclusión: En nuestro centro existe una excelente concordancia interobservador con buenos índices kappa en la interpretación ciega de los VQ solicitados por TEP. Este ejercicio además, sirvió como entrenamiento práctico para los residentes del centro.
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Humanos , Masculino , Adolescente , Adulto , Feminino , Pré-Escolar , Criança , Pessoa de Meia-Idade , Circulação Pulmonar , Embolia Pulmonar , Relação Ventilação-Perfusão , Interpretação Estatística de Dados , Embolia Pulmonar/fisiopatologia , Estudos Retrospectivos , Método Simples-Cego , Probabilidade , Compostos Radiofarmacêuticos , Sensibilidade e Especificidade , Variações Dependentes do ObservadorRESUMO
UNLABELLED: The aim of this trial was to evaluate in developing countries from different regions the diagnostic performance of (99m)Tc-sestamibi scintimammography (SM) in palpable breast lesions and to verify the clinical usefulness of a joint evaluation with mammography and SM. METHODS: From 10 countries, a total of 238 patients with palpable breast masses (n = 245) were included in this prospective multicenter trial. Prone SM was performed 10 min and 60-90 min (157 patients) after injection using an isotime acquisition of 10 min. Mammography was assessed by the same dedicated imaging radiologist according to breast imaging reporting and data system (BI-RADS) categories for malignancy and breast density. Masked SM findings and mammography findings were checked for a correlation with histopathology findings for excisional biopsy samples. Diagnostic values for breast cancer detection were calculated per lesion. RESULTS: Histopathology revealed 189 cancerous lesions and 56 benign lesions. The sensitivity and specificity of SM were 0.83 and 0.77, respectively. SM diagnostic values did not depend on the incidence of breast cancer in the country of origin or on the timing of imaging (early vs. delayed scans). On mammography, the technique yielded a sensitivity and specificity of 0.85 and 0.66, with 27 mammograms classified as BI-RADS category 1, 33 as category 2, 5 as category 3, 56 as category 4, and 124 as category 5. Thirty-seven lesions were considered to show increased radiologic density. No significant difference was found in SM diagnostic values among different BI-RADS categories or between the groups with low and high breast density. A sensitivity of 96% was calculated when SM and mammography results were combined, with 75% of all false-negative mammography findings classified as true-positive results by SM. CONCLUSION: SM complements mammography in patients with palpable masses and negative mammography findings.
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Neoplasias da Mama/diagnóstico por imagem , Mamografia , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Sestamibi , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , CintilografiaRESUMO
BACKGROUND: Radio-iodine is a definite therapy for Graves disease hyperthyroidism. However, the optimal dosage is still debatable. AIM: To assess the effects of different radioiodine doses on thyroid function and complications in patients with hyperthyroidism. MATERIAL AND METHODS: A retrospective analysis of 139 patients with hyperthyroidism, treated with ratio-iodine between 1988 and 1998. Radio iodine dose used was classified as low (< 10 mCi), intermediate (10-14.9 mCi) or high (> or = 15 mCi). RESULTS: Thirty-five patients were treated with low doses, 33 with intermediate doses and 71 with high doses. There were no differences between these patients in age, disease severity, frequency of post treatment euthyroidism or complications. Patients treated with low doses had a higher frequency of persistent hyperthyroidism than patients treated with high doses (25.7 and 4.2% respectively, p < 0.001). Likewise, the frequency of subsequent hypothyroidism was 60% in patients treated with low doses and 84.5% of those with high doses, in whom it also appeared earlier. Associated complications were clinically irrelevant. In seven patients, Graves ophthalmopathy progressed after treatment, but this progression was not associated with the dose used. CONCLUSIONS: Radio iodine in high doses is useful, safe and effective for the treatment of Graves hyperthyroidism.
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Hipertireoidismo/radioterapia , Radioisótopos do Iodo/administração & dosagem , Glândula Tireoide/efeitos da radiação , Adolescente , Adulto , Idoso , Criança , Feminino , Seguimentos , Doença de Graves/radioterapia , Humanos , Radioisótopos do Iodo/efeitos adversos , Masculino , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Estudos Retrospectivos , Glândula Tireoide/fisiopatologiaRESUMO
We report a 50-year-old woman with a recent myocardial infarction in whom a myocardial perfusion single photon emission computed tomography (SPECT) with Thallium201 was done simultaneously with a F18-fluorodeoxyglucose (FDG) SPECT to study glucose metabolism. Myocardial infarction was located in the anteroseptal and apical regions and an echocardiography, done at the second day of evolution, showed a septo-apical hypokinesia. On the tenth day, a coronary angiography showed a critical lesion of the anterior descending coronary artery and an angioplasty with stent placement was performed on the next day. On the twelfth day, a resting, redistribution 201Tl SPECT to study viability and a FDG-SPECT with a dual head high-energy collimator camera were done. Images, acquired 45 min after injection, were analyzed visually. In anterior and medial apical sectors, discordance between flux and metabolism, considered a classical mismatch, was observed. Echocardiographic hypokinesia disappeared three month after revascularization.