RESUMO
Intravenous digital angiography of the left ventricle (LV) was submitted to videodensitometric analysis in order to measure the ejection fraction (EF) and ventricular volumes. The video-densitometric method was first validated using an experimental model consisting of latex balloons filled with contrast medium. The correlation for ejection fraction measurements was satisfactory (r = 0.9449), with less than 10% errors. For ventricular volumes, the correlation was also good (r = 0.97 and 0.92 with the Chapman and Dodge methods respectively), but marked variations across individuals were found. Digital videodensitometry thus appears to be a feasible and reliable method for ejection fraction and ventricular volume measurements. Further studies are needed to determine the accuracy of measurements of ventricular volumes.
Assuntos
Volume Sistólico , Gravação em Vídeo/métodos , Densitometria , Feminino , Ventrículos do Coração/diagnóstico por imagem , Humanos , Masculino , Flebografia , Intensificação de Imagem RadiográficaRESUMO
Left ventricular (LV) function was studied in 30 patients using digital subtraction angiography by the intravenous approach. Each ventriculogram was processed with a specific videodensitometric analysis to determine LV ejection fraction. The program was verified in an experimental set-up consisting of nine latex balloons filled with contrast medium. Its validation has been established by comparing videodensitometric results with classical results supplied by geometric methods. A good correlation was obtained (r = 0.9449) and, furthermore, with experimental models, videodensitometric analysis seemed to be more accurate than geometric analysis. Digital videodensitometry appears to be a valuable and accurate method for quantifying LV function, and a promising technique for determination of the real volumes.
Assuntos
Volume Sistólico , Técnica de Subtração , Gravação em Vídeo , Adolescente , Adulto , Idoso , Angiografia/métodos , Densitometria , Feminino , Humanos , Masculino , Matemática , Pessoa de Meia-Idade , Intensificação de Imagem Radiográfica , Gravação em Vídeo/métodosRESUMO
Digitalisation enables angiocardiography to be performed by a peripheral intravenous injection. Computer-assisted analysis of the date widens the possibilities of quantification. The authors have developed a videodensitometric method of studying the left ventricular ejection fraction. The research was performed on an experimental model and the technique validated in a series of 10 patients. The experimental model consisted of a series of balloons which, when inflated with contrast medium assumed an allipsoid shape resembling a left ventricle. The balloons were blown up in two stages with an automatic injector to simulate systole and diastole. The images were recorded in the same way as during ventriculography. Videodensitometric measurements showed 3 to 5% variations from the true values. The method was then applied to the calculation of the left ventricular ejection fraction in 10 patients: left ventricular function was also quantified by geometrical methods (Dodge) from the same angiogrammes and the 2 sets of results were then compared. The correlation coefficient between the two methods was 0.97, so validating the new technique. Videodensitometry opens up new perspectives in the study of left ventricular function. On the other hand it can be used to monitor the ejection fraction in severely ill or recently operated patients, and, on the other hand the principle of videodensitometry eliminates the geometrical approximations inherent in the classical methods of angiographic analysis and would therefore seem to be more suitable for the study of pathological left ventricules (aneurysm...). Finally, the technique of videodensitometry represents a new step towards the measurement of true volumes and flow rates.
