RESUMEN
OBJECTIVE: The purpose of this article is to discuss the application of a new CT reconstruction algorithm, adaptive statistical iterative reconstruction (ASIR), to reduce radiation dose at body CT and to provide imaging examples in comparison with low-dose and standard-dose filtered back projection CT. CONCLUSION: The ASIR reconstruction algorithm is a promising technique for providing diagnostic quality CT images at significantly reduced radiation doses.
Asunto(s)
Algoritmos , Dosis de Radiación , Protección Radiológica/métodos , Tomografía Computarizada por Rayos X/métodos , Medios de Contraste , Humanos , Obesidad/diagnóstico por imagen , Traumatismos por Radiación/prevención & control , Intensificación de Imagen Radiográfica/métodos , Tomografía Computarizada por Rayos X/efectos adversosRESUMEN
OBJECTIVE: The purpose of this study was to evaluate the image noise, low-contrast resolution, image quality, and spatial resolution of adaptive statistical iterative reconstruction in low-dose body CT. MATERIALS AND METHODS: Adaptive statistical iterative reconstruction was used to scan the American College of Radiology phantom at the American College of Radiology reference value and at one-half that value (12.5 mGy). Test objects in low- and high-contrast and uniformity modules were evaluated. Low-dose CT with adaptive statistical iterative reconstruction was then tested on 12 patients (seven men, five women; average age, 67.5 years) who had previously undergone routine-dose CT. Two radiologists blinded to scanning technique evaluated images of the same patients obtained with routine-dose CT and low-dose CT with and without adaptive statistical iterative reconstruction. Image noise, low-contrast resolution, image quality, and spatial resolution were graded on a scale of 1 (best) to 4 (worst). Quantitative noise measurements were made on clinical images. RESULTS: In the phantom, low- and high-contrast and uniformity assessments showed no significant difference between routine-dose imaging and low-dose CT with adaptive statistical iterative reconstruction. In patients, low-dose CT with adaptive statistical iterative reconstruction was associated with CT dose index reductions of 32-65% compared with routine imaging and had the least noise both quantitatively and qualitatively (p < 0.05). Low-dose CT with adaptive statistical iterative reconstruction and routine-dose CT had identical results for low-contrast resolution and nearly identical results for overall image quality (grade 2.1-2.2). Spatial resolution was better with routine-dose CT (p = 0.004). CONCLUSION: These preliminary results support body CT dose index reductions of 32-65% when adaptive statistical iterative reconstruction is used. Studies with larger statistical samples are needed to confirm these findings.