RESUMEN
PURPOSE: We aimed to evaluate the quality of chest computed tomography (CT) images obtained with low-dose CT using three iterative reconstruction (IR) algorithms. METHODS: Two 64-detector spiral CT scanners (HDCT and iCT) were used to scan a chest phantom containing 6 ground-glass nodules (GGNs) at 11 radiation dose levels. CT images were reconstructed by filtered back projection or three IR algorithms. Reconstructed images were analyzed for CT values, average noise, contrast-to-noise ratio (CNR) values, subjective image noise, and diagnostic acceptability of the GGNs. Repeated-measures analysis of variance was used for statistical analyses. RESULTS: Average noise decreased and CNR increased with increasing radiation dose when the same reconstruction algorithm was applied. Average image noise was significantly lower when reconstructed with MBIR than with iDOSE4 at the same low radiation doses. The two radiologists showed good interobserver consistency in image quality with kappa 0.83. A significant relationship was found between image noise and diagnostic acceptability of the GGNs. CONCLUSION: Three IR algorithms are able to reduce the image noise and improve the image quality of low-dose CT. In the same radiation dose, the low-dose CT image quality reconstructed with MBIR algorithms is better than that of other IR algorithms.
Asunto(s)
Procesamiento de Imagen Asistido por Computador/métodos , Fantasmas de Imagen , Tórax/diagnóstico por imagen , Tomografía Computarizada por Rayos X/instrumentación , Algoritmos , Humanos , Variaciones Dependientes del Observador , Dosis de Radiación , Radiólogos , Cintigrafía/instrumentación , Relación Señal-RuidoRESUMEN
Defects or deficiencies in red cell membrane skeletal proteins often undermine the integrity and stability of the plasma membrane, and consequently cause hereditary hemolytic anemias. Genetic and biochemical studies have revealed a complicated picture of the organization of the membrane skeleton, within which α-/ß-spectrin heterodimers form a protein lattice. By stabilizing the red cell membrane skeleton, the erythroid protein 4.1R greatly contributes to connecting and regulating the interaction among spectrins, actin filaments and integral proteins on the plasma membrane. In this study, we demonstrated the direct interaction between 4.1R and α-/ß-spectrin. The results provide novel insights into the stoichiometry of 4.1R with spectrin, and demonstrate for the first time that the binding ratio of 4.1R to spectrin heterodimers is approximately 5.