Study of Myocardial Perfusion in Obese Individuals without Known Ischemic Heart Disease / Estudo de Perfusão Miocárdica em Obesos sem Doença Cardíaca Isquêmica Conhecida

Abstract Background: Obesity is associated with an increased risk of type 2 diabetes mellitus (DM), ischemic heart disease (IHD) and cardiovascular mortality. Several studies have demonstrated the diagnostic and prognostic value of single photon computed tomography-myocardial perfusion scintigraphy (SPECT-MPI) in the evaluation of patients with suspected IHD, including in obese population. Data on clinical risk factors and their association with abnormal myocardial perfusion in obese patients are scarce in the Brazilian population. Objective: To determine the factors associated with abnormal myocardial perfusion in obese individuals without known IHD. Methods: We studied obese patients without known IHD who were referred for evaluation through SPECT-MPI between January 2011 and December 2016. Clinical variables and results of SPECT-MPI were obtained systematically. The distribution of continuous variables was assessed using the Shapiro-Wilk and Shapiro-Francia tests. We used the unpaired Student t test to compare the means of continuous variables with normal distribution and the Chi Square test for binomial variables analysis. A p value < 0.05 was considered statistically significant. The association of the clinical variables for the presence of factors associated with abnormal myocardial perfusion was determined by univariate and multivariate logistic regression analysis, and respective odds ratios (OR) and 95% confidence intervals (CI). Results: The study sample consisted of 5,526 obese patients. Mean body mass index (BMI) of our patients was 33.9 ± 3.7 kg/m2, 31% had DM, and myocardial perfusion abnormalities was observed in 23% of the total sample. The factors associated with abnormal myocardial perfusion on multivariate analysis were: age (OR: 1.02, 95% CI 1.01-1.03, p < 0.001), DM (OR: 1.57, 95% CI 1.31-1.88, p < 0.001), typical angina before the test (OR: 2.45, 95% CI: 1.82-3.31, p < 0.001), need for pharmacologic stress test (OR: 1.61, 95% CI: 1.26-2.07, p < 0.001), less physical effort evaluated in metabolic equivalents (METs) during the exercise treadmill test (OR: 0.89, 95% CI: 0.85-0.94, p < 0.001) and a lower post-stress left ventricular ejection fraction after stress (LVEF; OR: 0.989, 95% CI: 0.984-0.994, p < 0.001). Conclusion: The factors associated with abnormal myocardial perfusion in obese patients without known IHD were age, DM, presence of typical angina, ventricular dysfunction, and inability to undergo physical stress as clinical variables, in addition to functional capacity during physical stress.

Resumo Fundamento: A obesidade associa-se a um risco aumentado de diabetes mellitus do tipo 2 (DM), doença cardíaca isquêmica (DCI) e mortalidade cardiovascular. Vários estudos demonstraram o valor diagnóstico e prognóstico da cintilografia de perfusão miocárdica com tomografia computadorizada por fóton único (CPM-SPECT) na avaliação de pacientes com suspeita de DCI, inclusive na população de obesos. Dados sobre fatores de risco clínicos, e sua associação com perfusão miocárdica anormal em obesos, são escassos na população brasileira. Objetivo: Determinar quais são os fatores associados à anormalidade de perfusão miocárdica em obesos sem DCI conhecida. Métodos: Estudamos pacientes obesos sem DCI conhecida que foram encaminhados para avaliação por CPM-SPECT entre janeiro de 2011 até dezembro de 2016. Variáveis clínicas e resultados da CPM-SPECT foram obtidos de forma sistematizada. A distribuição das variáveis contínuas foi avaliada utilizando-se os testes de Shapiro-Wilk e Shapiro-Francia. Utilizou-se o teste t de Student não pareado para comparar as médias das variáveis contínuas com distribuição normal, e o teste do Chi quadrado para análise das variáveis binomiais. Considerou-se o valor de p < 0,05 como estatisticamente significativo. A associação das variáveis clínicas para a presença de anormalidade de perfusão miocárdica foi determinada por análise de regressão logística univariada e multivariada, calculando-se e apresentando-se os respectivos odds ratios (OR) e intervalos de confiança (IC) de 95. Resultados: A amostra do estudo foi de 5.526 pacientes obesos. O índice de massa corporal médio dos nossos pacientes foi de 33,9 ± 3,7 kg/m2, 31% eram portadores de DM, e anormalidades de perfusão foram observadas em 23% do total da amostra. Os fatores associados à anormalidade de perfusão miocárdica, após análise multivariada, foram: idade (OR: 1,02, IC 95%: 1,01-1,03, p < 0,001), DM (OR: 1,57, IC 95%: 1,31-1,88, p < 0,001), presença de angina típica antes do exame (OR: 2,45, IC 95%: 1,82-3,31, p < 0,001), necessidade de utilização de protocolo com estresse farmacológico (OR: 1,61, IC 95%: 1,26-2,07, p < 0,001), menor esforço físico avaliado em equivalentes metabólicos durante o teste ergométrico (OR: 0,89, IC 95%: 0,85-0,94, p < 0,001) e menor fração de ejeção do ventrículo esquerdo após estresse (OR: 0,989, IC 95%: 0,984-0,994, p < 0,001). Conclusão: Os fatores associados à anormalidade de perfusão miocárdica em pacientes obesos sem DCI conhecida foram idade, DM, presença de angina típica, disfunção ventricular e incapacidade para o estresse físico como variáveis clínicas, além da capacidade funcional durante o estresse físico.

Evaluación de la recurrencia de tumores musculoesqueléticos mediante gammagrafía complementada con SPECT/CT con talio-201 en población pediátrica / Evaluation of recurrence of musculoskeletal tumors with thallium-201 scintigraphy plus SPECT/CT in pediatric population

Resumen Introducción: Los estudios de imagen, como la tomografía simple y contrastada, son la primera aproximación diagnóstica para detectar la recurrencia de tumores musculoesqueléticos. El objetivo de este estudio retrospectivo fue demostrar la utilidad de la gammagrafía acoplada a tomografía computarizada por emisión de fotón único (SPECT/CT) con talio-201(201Tl) en la valoración de tumores musculoesqueléticos malignos con sospecha de recurrencia o enfermedad metastásica. Métodos: Se realizaron 72 estudios gammagráficos y de SPECT/CT para la valoración de la recurrencia locorregional y a distancia, al menos 8 semanas tras la última terapia, en 42 pacientes con diferentes tipos de tumores musculoesqueléticos malignos, como osteosarcoma, sarcoma de Ewing, rabdomiosarcoma, retinoblastoma, sarcoma sinovial y tumor de Wilms en el Hospital Infantil de México. Se calcularon el valor predictivo positivo (VPP) y el intervalo de confianza del gammagrama y de la SPECT/CT en comparación con el resultado del análisis histopatológico y el seguimiento clínico y radiológico para identificar la recurrencia. Resultados: La gammagrafía fue anormal en 30 (71.4%) de los 42 pacientes. Se detectaron 33 lesiones (30 pacientes) por gammagrafía y 25 (21 pacientes) por telerradiografía de tórax y tomografía de dos regiones. La SPECT/CT se realizó en 30 pacientes y se detectaron 12 lesiones adicionales al rastreo planar. El VPP con la gammagrafía fue del 82%, y con la SPECT/CT, del 100%. Conclusión: La gammagrafía con 201Tl puede considerarse un estudio adecuado para identificar los sitios de viabilidad tumoral, con alto grado de certeza diagnóstica al complementar con SPECT/CT.

Abstract Background: Imaging studies, particularly simple and contrast-enhanced tomography, constitute the first diagnostic approach to detect recurrence of musculoskeletal tumors. The aim of the present retrospective study was to demonstrate the usefulness of scintigraphy plus SPECT/CT (single photon emission computed tomography) with thallium-201 (201Tl) in the evaluation of malignant musculoskeletal tumors with suspicion of recurrence or metastatic disease. Methods: Eight weeks after the last therapy, 72 scintigraphy and SPECT/CT studies were performed to assess regional recurrence and metastatic disease in 42 patients with different types of malignant musculoskeletal tumors, such as osteosarcoma, Ewing's sarcoma, rhabdomyosarcoma, retinoblastoma, synovial sarcoma, and Wilms tumor at the Hospital Infantil de México Federico Gómez. The positive predictive value (PPV) and the confidence interval of the scintigraphy and SPECT/CT were calculated when compared with the results of the histopathological analysis and the clinical and radiological follow-up for the identification of recurrence. Results: Scintigraphy was abnormal in 30 (71.4%) of the 42 patients; 33 lesions (30 patients) were detected by scintigraphy and 25 lesions (21 patients) by chest X-ray and tomography of two regions. The SPECT/CT was performed on 30 patients, where 12 lesions were detected in addition to the planar scintigraphy. Scintigraphy showed a PPV of 82%; SPECT/CT, 100%. Conclusion: 201Tl-scintigraphy can be considered as an adequate study to identify the sites of tumor viability with a high degree of diagnostic certainty combined with the SPECT/CT technique.

Intrathoracic stomach mimicking bone metastasis from thyroid cancer in whole-body iodine-131 scan diagnosed by SPECT/CT

SUMMARY The whole-body iodine-131 scintigraphy is an imaging technique in monitoring patients with a history of thyroid cancer. Although the rate of false positives is negligible, it is not nonexistent. We report the case of an intervened and treated patient for thyroid cancer with good clinical and biochemical response. Scintigraphic findings were consistent with unsuspected bone metastasis. Fused SPECT/CT data allowed accurate diagnosis of giant diaphragmatic hernia associated with intrathoracic stomach, a very rare pathology that can lead to false positive results.