RESUMO
The purpose of this study was to assess the influence of patient gender and choice of perfusion tracer on computer-based interpretation of myocardial perfusion images. For the image interpretation, an automated method was used based on image processing and artificial neural network techniques. A total of 1000 patients were studied, all referred to the Royal Brompton Hospital in London for myocardial perfusion scintigraphy over a period of 1 year. The patients were randomized to receive either thallium or one of the two technetium tracers, methoxyisobutylisonitrile or tetrofosmin. Artificial neural networks were trained with either mixed gender or gender-specific and mixed tracer or tracer-specific training sets of different sizes. The performance of the networks was assessed in separate test sets, with the interpretation of experienced physicians regarding the presence or absence of fixed or reversible defects in the images as the gold standard. The neural networks trained with large mixed gender training sets were as good as the networks trained with gender-specific data sets. In addition, the neural networks trained with large mixed tracer training sets were as good as or better than the networks trained with tracer-specific data sets. Our results indicate that the influence of patient gender and perfusion tracer are of minor importance for the computer-based interpretation of the myocardial perfusion images. The differences that occur can be compensated for by larger training sets.
Assuntos
Cardiopatias/diagnóstico por imagem , Redes Neurais de Computação , Compostos Radiofarmacêuticos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Compostos Organofosforados , Compostos de Organotecnécio , Curva ROC , Cintilografia , Fatores Sexuais , Tecnécio Tc 99m Sestamibi , Radioisótopos de TálioRESUMO
UNLABELLED: There are no large studies available to guide the selection of thallium (Tl), methoxyisobutylisonitrile (MIBI) or tetrofosmin (Tf) for myocardial perfusion imaging. Our objective was to compare the technical and clinical performance of the three in routine clinical practice. We randomised 2,560 patients to receive Tl, MIBI or Tf. A 1-day stress/rest protocol was used for MIBI and Tf. Tracer uptake was scored using a 17-segment model, quality and artefact scores were assigned, and ratios of heart (H), liver (L), subdiaphragmatic (S) and lung activity were measured. Mean quality scores (stress/rest) were Tl 2.13/2.16, MIBI 2.18/2.39, Tf 2.18/2.42 ( P=ns stress and <0.00001 rest). For attenuation artefact, Tl>MIBI=Tf ( P<0.05) and for low-count artefact Tl>MIBI>Tf ( P<0.001). For H/S, Tl>MIBI=Tf, for H/L Tl>MIBI=Tf, and for H/lung TlAssuntos
Cardiopatias/diagnóstico por imagem
, Coração/diagnóstico por imagem
, Compostos Organofosforados
, Compostos de Organotecnécio
, Tecnécio Tc 99m Sestamibi
, Tálio
, Adenosina
, Artefatos
, Doença das Coronárias/diagnóstico por imagem
, Estudos Transversais
, Dobutamina
, Teste de Esforço
, Humanos
, Miocárdio/metabolismo
, Compostos Organofosforados/farmacocinética
, Compostos de Organotecnécio/farmacocinética
, Controle de Qualidade
, Radiografia
, Cintilografia
, Compostos Radiofarmacêuticos/farmacocinética
, Reprodutibilidade dos Testes
, Sensibilidade e Especificidade
, Tecnécio Tc 99m Sestamibi/farmacocinética
, Tálio/farmacocinética
, Reino Unido