Optimization research on preparation conditions of polymer-shelled microbubble contrast agents / 中国组织工程研究

BACKGROUND:In previous experiments, a polymer-shel ed microbubble contrast agent was successful y prepared using L-polylactic acid-polyethylene glycol methyl-covered liquid fluorocarbon perfluoropentane, which developed wel in vivo and in vitro under a second harmonic contrast-enhanced ultrasound with a low mechanical index OBJECTIVE:To optimize the conditions for preparing polymer-shel ed microbubble contrast agents with high yield and suitable size. METHODS:The polymer-shel ed microbubble contrast agent containing perfluoropentane was prepared by single emulsion method. Three preparation conditions, including polymer mass/perfluoropentane volume ratio (4/1, 2/1, 1/1, 1/2), hemogenate speed (18 000, 26 000, 35 000 r/min) and time (15, 30, 60, 120 seconds), were optimized, and the microbubble yield and size were set as judge standard. The contrast-enhanced ultrasonography of rabbit kidney was performed using the optimized microbubbles, and the arrival time, time to peak, half time of descending and peak intensity were analyzed by TCA software. RESULTS AND CONCLUSION:The preparation conditions were optimized as a polymer mass/perfluoropentane volume ratio of 2/1, homogenate speed of 26 000 r/min and homogenate time of 60 seconds, which presented a high microbubble yield of (1.8±0.4)×109/mL and mean size of (3.7±1.3)μm with uniform distribution. The arrival time, time to peak, half time of descending and peak intensity were detected as (3.1±0.6) seconds, (2.9±0.5) seconds, (4.0±0.7) seconds and (4.7±1.1)×10-5 AU, respectively. The polymeric microbubbles prepared by optimized conditions were of high yield, with suitable size and good contrast-enhanced effect in vivo.

Nefropatía por contraste en el síndrome coronario agudo / Contrast induced nephropathy in acute coronary syndrome

La nefropatía inducida por contraste (NIC) es una de las causas más frecuentes de insuficiencia renal en pacientes internados. En el síndrome coronario agudo (SCA), la presencia de NIC aumenta la morbimortalidad. Las medidas de profilaxis y los factores de riesgo intervinientes de NIC en SCA no han sido determinados con exactitud. El objetivo de este estudio fue evaluar la incidencia de NIC y los factores asociados a su desarrollo en pacientes ingresados en unidad coronaria con requerimiento de cinecoronariografía (CCG). Se realizó un estudio de cohorte retrospectivo. Se incluyeron pacientes consecutivos cursando SCA estudiados con CCG dentro de las 72 horas de su admisión. Se definió NIC al aumento del 25% del valor de creatinina a las 48 h sobre el nivel basal de ingreso. El período de inclusión fue entre el 1° de enero de 2004 hasta el 30 de junio de 2010. Se analizaron 125 casos. La incidencia de NIC fue del 10.4% (n = 13). En el análisis multivariado, los factores asociados independientemente a su desarrollo fueron la edad [OR 1.05 (IC 95% 1.004 - 1.11) p = 0.034], la angioplastia a múltiple vaso [OR 2.2 (IC 95% 1.07 - 4.8), p = 0.03] y el volumen de contraste utilizado [OR 1.007 (IC 95% 1.001 - 1.01), p = 0.014].

Contrast induced nephropathy (CIN) is one of the most frequent causes of acute renal failure in hospitalized patients. It is associated with an increase in morbidity and mortality in patients hospitalized for acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). Risk factors and prevention strategies are not well defined. The aim of this study was to assess the incidence and clinical risk factors associated to the development of contrast induced nephropathy in patients hospitalized for ACS. In a retrospective cohort we analyzed consecutive patients hospitalized for ACS undergoing urgent PCI within 72 hours from the admission. CIN was defined as a 25% increase of creatinine levels from baseline at 48 hours from the PCI. The inclusion period was from January 1°, 2004 to June 30, 2010. A total of 125 patients were analyzed, and CIN occurred in 13 (10.4%) patients. An independent association was found between age (OR 1.05; 95% CI 1.004 to 1.11; p = 0.034), multiple vessel angioplasty (OR 2.2; 95% IC 1.07 to 4.8; p = 0.03) and the volume of contrast infused (OR 1.007; 95% CI 1.001 to 1.01; p = 0.014) with the development of CIN.

Reduced Volume of Contrast Media: Effect on Vascular Opacification and Image Quality in Spiral CT of the Chest

PURPOSE: To evaluate the effect of reduced volume of contrast media on vascular opacification and image quality in spiral CT of the chest. MATERIALS AND METHODS: Sixty patients referred for chest CT were examined withspiral CT with 60ml(n=30) or 90ml(n=30) of 30% ionic contrast media(Rayvist 300 , Schering, Germany) alternately.Injection rate of each group was as follows : 2.0 ml/sec for 20 seconds followed by 1.0 ml/sec for 20 seconds in 60ml group and 2.0ml/sec for 45 seconds in 90ml group. Twenty-five seconds scanning delay was employed. For the objective comparison of vascular opacification, CT numbers were measured at superior vena cava, ascending and descending aorta, right and left pulmonary artery, left atrium, and inferior vena cava. For the subjective comparison three radiologists scored the grade of vascular opacification and image quality blindly and independently. All data were analyzed statistically. RESULTS: The mean values of measured CT numbers in 90ml group were higher than those in 60ml group(p <.05) at the same level. The overall mean score of vascular opacification in 90ml group was 2.86, and 2.31 in 60ml group(p <.0001). In the overall mean score of imagequality, there was no statistically significant difference between 90ml group(2.46) and 60ml group(2.40). CONCLUSION: Althought there is some degradation of vascular opacification in 60ml group, overall image quality is not degraded. Therefore, 60 ml of contrast media can be used in spiral CT of the chest without degradation ofoverall image quality except in spiral CT angiography.