RESUMEN
UNLABELLED: Exercise lung 201 TI uptake calculated with planar imaging has an important diagnostic and prognostic value in patients with coronary artery disease (CAD). However, its value with SPECT imaging raises methodological concerns and is controversial. We studied its value for the discrimination between extensive (E) and limited (L) angiographic CAD with exercise SPECT. METHODS: Four methods of lung-to-heart ratio quantification were calculated in patients with a low likelihood (< 5%) of CAD (n = 62). Their dependent variables were defined, and corresponding correction equations were derived. Receiver operating characteristic (ROC) analysis was performed in a pilot group (L-CAD, n = 49; E-CAD, n = 126) to define the optimal method of calculation of the lung-to-heart ratio. Its best threshold providing the best sensitivity for a specificity of 90% was defined. After correction for dependent variables, the 4 methods were also compared by ROC analysis and the optimal corrected method was compared with the optimal uncorrected method using ROC analysis and the best threshold. The consistency of these results in the validation group (L-CAD, n = 41; E-CAD, n = 122) and of the results of visual analysis of lung 201TI uptake were then verified. RESULTS: On ROC analysis in the pilot group, the optimal method of calculation of the lung-to-heart ratio was the mean activity in a region of interest drawn at the base of the lungs to the mean activity over the heart (Lb/H). For the best threshold, Lb/H presented a sensitivity of 34%. Corrected Lb/H still remained the best method of calculation on ROC analysis compared with the other corrected methods. On ROC analysis, there was no difference between corrected and uncorrected Lb/H. For the best threshold, corrected Lb/H presented a similar sensitivity of 37% compared with uncorrected Lb/H. When applied to the validation group (L-CAD, n = 41; E-CAD, n = 122), the best-defined threshold in the pilot group for corrected Lb/H presented a diagnostic value similar to that in the pilot group (sensitivity, 41%; specificity, 90%), but uncorrected Lb/H presented a higher sensitivity (47%; P < 0.04) and a slightly lower specificity (80%). Results of lung 201TI uptake visual analysis were inconsistent between pilot and validation groups (42% versus 58% sensitivity, P = 0.012; 86% versus 66% specificity, P = 0.023). CONCLUSIONS: For evaluation of E-CAD versus L-CAD, quantification of the exercise lung-to-heart 201TI uptake ratio with SPECT is feasible, reproducible, more discriminate than simple visual analysis, and best calculated as Lb/H. It presents an intrinsic diagnostic value even after correction for other clinically valuable dependent variables.
Asunto(s)
Enfermedad Coronaria/diagnóstico por imagen , Pulmón/diagnóstico por imagen , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón Único , Estudios de Casos y Controles , Angiografía Coronaria , Enfermedad Coronaria/epidemiología , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Curva ROC , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Submaximal exercise tests have been advocated to assess exercise capacity in chronic heart failure, but hemodynamic responses have not been characterized. To determine left ventricular (LV) responses during submaximal exercise, the LV ejection fraction (EF) and volumes were evaluated by using an ambulatory radionuclide detector in 13 patients with idiopathic dilated cardiomyopathy during upright maximal graded bicycle exercise, stair climbing and a 6-minute walk test. The 3 tests elicited different responses in volumes and, to a lesser degree, in LVEF. The maximal bicycle exercise led to a decrease in LVEF from 22 +/- 9% to 17 +/- 8% (p <0.05), with marked increases in both end-diastolic volume (EDV) (+15 +/- 10%, p <0.001) and end-systolic volume (ESV) (+23 +/- 18%, p <0.001). Stair climbing tended to reduce LVEF (from 24 +/- 11% to 21 +/- 10%, p = 0.05), with a lesser increase in volumes, which was more marked for ESV (+8 +/- 9%, p <0.01) than for EDV (+4 +/- 4%, p <0.01). The 6-minute walk test did not significantly change LVEF (23 +/- 10% vs 22 +/- 10%), but increased both EDV (+10 +/- 6%, p <0.001) and ESV (+8 +/- 8%, p <0.01) moderately and proportionally. Exercise capacity indexes (peak oxygen consumption, maximal bicycle work rate, stair climbing time, and the distance covered during the 6-minute walk test) correlated significantly with one another. There was no correlation between submaximal exercise tolerance indexes and resting or exercise LVEF. This study shows that (1) LVEF changes are inadequate to report on LV volume changes during exercise; (2) the 3 tests induce different LV volume changes; (3) the 6-minute walk test induces significant changes in LV volumes but no change in LVEF.
Asunto(s)
Cardiomiopatía Dilatada/fisiopatología , Ejercicio Físico/fisiología , Función Ventricular Izquierda/fisiología , Adulto , Anciano , Cardiomiopatía Dilatada/diagnóstico por imagen , Prueba de Esfuerzo , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno/fisiología , Ventriculografía con Radionúclidos , Volumen Sistólico/fisiologíaRESUMEN
It has been suggested that the pineal gland has a specific role in the control of cyclic sexual activity in rats. One or more of the compounds isolated from this gland have been considered to be possible anti-fertility agents. In this study, the effect of different doses of 5-methoxyindole-3-acetic acid (5-MIAA) on the estrous cycle and the reproductive organs of female rats was studied. Daily injections of either 100 or 200 micrograms of 5-MIAA significantly prolonged the estrous cycles of mature female rats. After injections of 5-MIAA, an increase in diestrous smears was observed; in addition, the animals had estrous cycles without proestrous phase. Following the injections of 200 micrograms of 5-MIAA, a significant increase in uterine weight, plasma 17 beta-estradiol level and in the number of follicles were observed, and after injections of 5-MIAA (50, 100, 200 micrograms) a medium level of plasma progesterone was obtained. Thus it is concluded that 5-MIAA has an effect on the ovulation process of female rats.