RESUMEN
Negative product value for coronary artery disease is 98% to 99%. Therefore, the number of unnecessary cardiac catheterization procedures is reduced as the usefulness of CT systems for examination of the coronary arteries improves. In the bolus-tracking method, in which an ROI is placed in the ascending aorta to trigger scanning, scanning may not be performed at the optimal time of contrast enhancement depending on the patient. In addition to identifying the causes of this problem, we have developed a new method in which ROIs are placed in the right ventricle and left atrium to trigger scanning when the concentrations of contrast medium in the right ventricle and left atrium become equal. The two methods were then compared and evaluated. In the scan method, in which an ROI is placed in the ascending aorta, the reason for non-optimal scan timing is considered to be that the time required for contrast medium injected via an antecubital vein to reach the heart varies depending on the individual patient(approximately 3 times the variation of our method)followed by a delay of approximately 5 seconds between the scan trigger time and the actual scan start time. In the scan method in which scanning is triggered when the concentrations of contrast medium in the right ventricle and left atrium become equal, scanning can be performed at the time of peak enhancement regardless of differences in the time required for the injected contrast medium to reach the target region or differences in the injection rate, demonstrating the usefulness of this method.
Asunto(s)
Medios de Contraste/administración & dosificación , Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Anciano , Anciano de 80 o más Años , Aorta , Peso Corporal , Gasto Cardíaco , Medios de Contraste/farmacocinética , Femenino , Atrios Cardíacos/metabolismo , Ventrículos Cardíacos/metabolismo , Humanos , Inyecciones Intravenosas , Masculino , Persona de Mediana Edad , Factores de TiempoRESUMEN
To investigate the clinical usefulness of coronary arteriography using a gadolinium contrast medium (hereinafter referred to as Gd contrast medium) in patients with iodine allergy, images obtained using an iodinated contrast medium and a Gd contrast medium were compared using respective phantoms. Within the range of the effective energy (34.8 to 41.0 keV) in clinical use, the tube-voltage dependency of the Gd contrast medium was lower than that of the iodinated contrast medium. The contrast ratios were found to be comparable for the images obtained by a 4-fold-diluted iodinated contrast medium and the undiluted Gd contrast medium. Although the assessment of stenotic ratio was difficult to obtain by visual evaluation of the clinical images, due to unclear borders of the blood vessels, the presence or absence of significant stenosis was discriminative by arteriography using the Gd contrast medium. Based on these findings, it was considered necessary to make a confirmed diagnosis using a Gd contrast medium with concurrent diagnosis by intravascular echography. In conclusion, coronary arteriography and PCI using a Gd contrast medium are considered to offer benefit to the diagnosis and treatment of patients with iodine allergy.
Asunto(s)
Medios de Contraste , Angiografía Coronaria/métodos , Gadolinio , Angioplastia Coronaria con Balón/métodos , Medios de Contraste/efectos adversos , Hipersensibilidad a las Drogas/etiología , Humanos , Yodo/efectos adversos , Fantasmas de ImagenRESUMEN
The INNOVA 2000, an all-digital cardiovascular X-ray system with flat panel detector, is equipped with a monitoring function that makes it possible to track a patient's absorbed dose by displaying the real-time presumed absorbed dose. We verified this dose monitoring system and evaluated how it is affected by various parameters. We also compared the INNOVA 2000 to a conventional machine, the Advantx LC. The average absorbed dose of the INNOVA 2000 was 1,066 mGy, while that of the Advantx LC was calculated to be 2,028 mGy. Dose reduction with the INNOVA 2000 was 76% at Low mode and 52% even at Normal mode. The INNOVA provides an advantage in lowering absorbed dose, even considering that it has a rectangular image intensifier (I.I.) versus the Advantx LC's round I.I. This comparison was made by cine and digital angiography.