RESUMO
Three methods are presented which provide statistically acceptable estimates of mean transit time of opacified blood during angiography. While the methods vary in precision, the selection of the method appropriate for any particular experimental model depends on the degree of precision required to demonstrate the effect under investigation. As the day follows the night, the cost of equipment increases with increasing precision and the inexpensive method may provide sufficient accuracy for most clinical situations.
Assuntos
Velocidade do Fluxo Sanguíneo , Angiografia/métodos , Animais , Cães , TelevisãoRESUMO
In the canine model there exist major differences in the velocity-displacement relationships of systolic contraction between normal and ischemic myocardium. These differences are noninvasively measurable in vivo from video recordings of the fluoroscopic image of the heart, and can be detected within the time period of one cardiac cycle. Velocity data is plotted against the corresponding wall displacement on orthogonal axes (phase-space), producing characteristic loops which give an immediate visual indication of myocardial dysfunction.
Assuntos
Doença das Coronárias/fisiopatologia , Contração Miocárdica , Animais , Doença das Coronárias/diagnóstico por imagem , Cães , Fluoroscopia , Gravação de VideoteipeRESUMO
Pulmonary videodensitometry permits the detection of vascular pulsations of the lung caused by the incremental blood flow to the lung associated with systole. These pulsations may be diminished or absent in a segment of the lung affected by carcinoma. Of 46 patients evaluated, 12 had carcinoma. The technique is discussed and representative amplitude changes are demonstrated. This technique should prove useful in the detection of processes which alter the pulmonary vascular pulsations.
Assuntos
Absorciometria de Fóton , Neoplasias Pulmonares/diagnóstico por imagem , Gravação de Videoteipe , Eletrocardiografia , Humanos , Neoplasias Pulmonares/irrigação sanguínea , Masculino , Pessoa de Meia-IdadeRESUMO
Videodensitometry of the margins of the fluoroscopic image of the left ventricle (LV) was used to evaluate LV wall motion and differentiation of the wall motion signal reflected velocity of LV contraction (dV/dt) during various inotropic interventions in six anesthetized dogs. During these interventions heart rate, afterload and preload were maintained constant. Alterations in dV/dt were similar to changes in simultaneously measured LV peak dP/dt and the quotient of dP/dt and developed LV pressure, two widely accepted parameters of LV contractile state. Wide variations in preload and afterload caused no significant changes in dV/dt. Thus, the current study indicates that fluoroscopic videodensitometry provides a specific and reliable noninvasive method for evaluating LV contractile state.
Assuntos
Absorciometria de Fóton , Ventrículos do Coração/diagnóstico por imagem , Gravação de Videoteipe , Animais , Pressão Sanguínea/efeitos dos fármacos , Cães , Isoproterenol/farmacologia , Modelos Biológicos , Ouabaína/farmacologia , Pentobarbital/farmacologia , Estimulação Química , Função VentricularRESUMO
The clinical, roentgenographic and aortographic data were reviewed in 12 patients with localised descending, thoracic aortic aneurysms. The current study indicates that arteriosclerotic peripheral vascular disease not infrequently produced localised saccular aneurysms of the descending thoracic aorta. Characteristic symptomatology was unusual; most aneurysms were detected as incidental roentgenographic findings. The aneurysms projected from the posteroloteral aspect of the aorta and roentgenographically appeared as left hilar masses or left retrocardiac masses when located in the mid and lower descending thoracic aorta, respectively. Specific rim calcification or vertebral erosion was not encountered in any case. During aortography only a small portion of the aneurysm was outlined with contrast material due to partial obliteration of the aneurysmal cavity with thrombus.
Assuntos
Aorta Torácica/diagnóstico por imagem , Aneurisma Aórtico/diagnóstico por imagem , Adulto , Idoso , Aorta Torácica/patologia , Aorta Torácica/cirurgia , Aneurisma Aórtico/patologia , Aneurisma Aórtico/cirurgia , Arteriosclerose/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , RadiografiaRESUMO
Videodensitometry of the margins of the fluoroscopic image of the left ventricle (LV) was used to evaluate LV wall motion. Differentiation of the wall motion signal reflected the velocity of LV contraction (dv/dt) during various inotropic interventions in 6 anesthetized dogs. Alterations in dv/dt were similar to changes in simultaneously measured LV peak dP/dt and the quotient of dP/dt and developed LV pressure, two widely accepted parameters of LV contractile state.
Assuntos
Densitometria , Fluoroscopia , Coração/fisiologia , Monitorização Fisiológica , Conversão Análogo-Digital , Animais , Densitometria/instrumentação , Cães , Eletrocardiografia , Eletrônica Médica/instrumentação , Fluoroscopia/instrumentação , Coração/efeitos dos fármacos , Frequência Cardíaca , Isoproterenol/farmacologia , Estimulação Química , Televisão , Função VentricularRESUMO
Frequency spectral analysis of cardiac wall motion as calculated from the recorded video kymogram are demonstrated. Characteristic harmonics following the fundamental frequency of the cardiac rate have been demonstrated to have an alternating sequential energy distribution as measured from the free margin of the left ventricle of humans. The characteristic patterns occur in approximately 80% of the 50 patients evaluated. The correlation of these harmonics with physiologic events is not yet complete. Amplitude frequency spectral analysis offers an objective method for analysis of cardiac kymography not otherwise possible.
