RESUMEN
Bedside chest radiographic examinations in intensive care units with grids are impaired by artefacts caused by angulation of the grid (grid cut-off). Two different grids--a grid with a high strip density of 70 lines per cm and the "InSight portable imaging system"--were examined in an intensive care unit with respect to their susceptibility to angulation, image quality and handling of the grid. Five radiologists compared 50 radiographs of each grid considering ten image quality criteria. Using the "InSight portable imaging system" major artefacts were undetectable even at an angulation of 10%; no adjustment of the grid was required, which reduced the amount of time needed to take the radiograph by 26%. The increase in dosage demanded by the employment of the grids at low kilovolt peak setting could be partially compensated by the use of high kilovolt peak setting. The image quality of the "InSight portable imaging system" together with a high kilovolt peak setting is satisfactory, and due to its simplified handling, the portable imaging system has proved to be suitable for bedside chest radiography in intensive care.
Asunto(s)
Sistemas de Atención de Punto , Intensificación de Imagen Radiográfica/métodos , Radiografía Torácica/métodos , Artefactos , Humanos , Unidades de Cuidados Intensivos , Intensificación de Imagen Radiográfica/instrumentación , Radiografía Torácica/instrumentación , RadiometríaRESUMEN
Bedside chest radiographic examinations in intensive care units with grids and high kilovoltage-peak settings are impaired by artifacts caused by the angulation of the grid (grid cutoff). We have tried to optimize the use of grids in bedside chest radiographic examinations. The sensitivity to the effect of grid cutoff was examined in two grids with the same grid ratio (12:1) but different numbers of lamelle per cm (40 versus 70) using a water-phantom. The alignment of the grid in a bedside setting was optimised. 100 chest examinations in the intensive care unit were compared by five radiologists according to ten criteria. Grids with a high number of lamelle per cm (70) proved to be less sensitive to the effects of grid cutoff. By positioning the grid with the lamelle vertical to patient's body-axis, asymmetric exposure of the lungs could be avoided. In addition, this setting allows an easy alignment of the grid by adjusting the grid together with the moveable part of the patient's bed. In examinations with grids, the advantages of high kilovoltage-peak setting were apparent. Bedside radiographic examinations in intensive care units with grids with a high number of lamelle and high-kilovoltage-peak setting can be performed without any major additional effort. By this method the image quality can be improved, especially in lungs with increased scatter-radiation.