Asunto(s)
Enfermedades de las Válvulas Cardíacas/diagnóstico , Ultrasonografía , Insuficiencia de la Válvula Aórtica/diagnóstico , Estenosis de la Válvula Aórtica/diagnóstico , Femenino , Prótesis Valvulares Cardíacas , Humanos , Masculino , Persona de Mediana Edad , Insuficiencia de la Válvula Mitral/diagnóstico , Estenosis de la Válvula Mitral/diagnóstico , Falla de Prótesis/diagnóstico , Presión Esfenoidal PulmonarRESUMEN
On the hypothesis that Doppler ultrasound fails to penetrate prosthetic valves, an in vitro flow simulation system was constructed in a large water tank. Conventional pulsed, continuous wave and Doppler color flow systems were used to detect flow in tubing placed diagonally within the water and maintained by a continuous pump. After control periods of flow detection within the tubing, six different prosthetic valves were interposed on a stage between the transducer and the tubing. In comparison with control measurements, detection of flow within the tubing was impossible when the Doppler beam traversed the central occluding ball of the Starr-Edwards Silastic prosthesis by any modality. Marked reduction in the detection of the Doppler signal was noted for the Starr-Edwards stellite prosthesis with only slight improvement in the ability to detect the flow signals through the central occluding discs of the Björk-Shiley, Hall-Kastor and St. Jude valves. In distinction to the other valves, the ability of Doppler ultrasound to detect flow behind the cusps of the Carpentier-Edwards heterograft was similar to that during the control period. An understanding of flow masking should improve the clinical utility of Doppler methods for investigating prosthetic valve dysfunction.
Asunto(s)
Prótesis Valvulares Cardíacas , Ultrasonido/métodos , Color , Estudios de Evaluación como Asunto , Humanos , Falla de Prótesis/diagnóstico , Ultrasonido/normas , Ultrasonografía/normasRESUMEN
On the basis of the literature and their personal experience, the authors describe the semiology, limits and complementary character of the current imaging techniques in the diagnosis of hip and knee arthroplasty failures.
Asunto(s)
Prótesis de Cadera/efectos adversos , Prótesis Articulares/efectos adversos , Falla de Prótesis/diagnóstico , Artrografía , Falla de Equipo , Fracturas Óseas/diagnóstico , Humanos , Luxaciones Articulares/diagnóstico , Osificación Heterotópica/diagnóstico , Flebografía , Complicaciones Posoperatorias/diagnóstico , Seudoartrosis/diagnóstico , Seudoartrosis/etiología , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/etiología , Tromboflebitis/diagnóstico , Tromboflebitis/etiología , Tomografía Computarizada por Rayos X , UltrasonografíaRESUMEN
Spontaneous echocardiographic contrast is caused by increased ultrasonic density in the cardiac chambers or great vessels, or both, with the characteristic flow pattern of blood, but in the absence of any intravascular injections. This study demonstrated the clinical features and characteristics of the echocardiographic findings of eight patients with spontaneous contrast echoes. Spontaneous contrast echoes were observed in the right heart in five patients, and in the left heart in two. In one patient spontaneous contrast echoes were observed in the right and left heart. All six patients with spontaneous contrast echoes in the right heart had impaired liver function. In these patients, we observed that spontaneous contrast reaching the heart via the hepatic vein on two-dimensional echocardiography. In one patient with atrial septal defect, these contrast echoes were also recognized in the superior mesenteric vein and portal vein. Since capillary beds normally remove ultrasound contrast, the failure of this function suggests porta-systemic shunting in or around the liver. All three patients with spontaneous contrast echoes in the left heart had prosthetic valve dysfunction including paravalvular or transvalvular regurgitation, and consequent hemolysis. Under these conditions, water-vapor bubbles may be formed because of an exhaust pressure decrease due to the Bernoulli effect, or gases may be released from erythrocytes during hemolysis. These water-vapor bubbles or gases could be the cause of spontaneous contrast echoes in the left heart. In conclusion, spontaneous contrast echoes in the right heart are produced by gas absorbed from the intestine because of porta-systemic shunting. The cause of spontaneous left-sided heart echo contrast may be related to prosthetic valve regurgitation, and consequently to hemolysis.
Asunto(s)
Ecocardiografía , Enfermedades de las Válvulas Cardíacas/diagnóstico , Adulto , Anciano , Femenino , Prótesis Valvulares Cardíacas , Hemólisis , Humanos , Masculino , Persona de Mediana Edad , Falla de Prótesis/diagnósticoRESUMEN
A radiopaque synthetic sponge is proposed as a prosthesis for microvascular decompression. Displacement of the prosthesis can be easily detected on a plain x-ray skull film.