RESUMO
OBJECTIVE: The aim of this study was to present initial evaluation of the performance of the iterative model reconstruction algorithm (IMR) in abdominal computed tomography (CT). METHODS: Computed tomographic examinations were performed for clinical study of 36 patients and for phantom study. We reconstructed the raw data with 1.0- and 5.0-mm slice thicknesses using filtered back projection (FBP), iDose4, and IMR and evaluated image quality objectively and subjectively. RESULTS: For almost all subjective characteristics, the image quality was better using IMR than iDose4. Objective image noise was significantly less using IMR than iDose4 (P < 0.0001). The contrast-noise ratio of both slice thicknesses increased in order from FBP to iDose4 to IMR. The spatial resolution of reconstructed images was almost identical using IMR, FBP, and iDose4. CONCLUSIONS: The IMR can significantly improve image noise and low-contrast resolution and maintain edge sharpness in abdominal CT images compared with iDose4 or FBP.
Assuntos
Hepatite Crônica/diagnóstico por imagem , Cirrose Hepática/diagnóstico por imagem , Modelos Biológicos , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Radiografia Abdominal/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso de 80 Anos ou mais , Algoritmos , Simulação por Computador , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Projetos Piloto , Radiografia Abdominal/instrumentação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/instrumentaçãoRESUMO
Inverse electron-demand aza Diels-Alder reaction of aldimine with enol ethers proceeded under the influence of a phosphoric acid diester, derived from (R)-BINOL, to give tetrahydroquinoline derivatives with excellent enantioselectivity.
Assuntos
Hidroquinonas/síntese química , Iminas/química , Alcenos/química , Catálise , Ciclização , Concentração de Íons de HidrogênioRESUMO
[reaction: see text] A cyclic phosphoric acid derivative, derived from (R)-BINOL, was used as a chiral Brønsted acid (10 mol %) in hydrophosphonylation of aldimines with diisopropyl phosphite at room temperature. Alpha-amino phosphonates were obtained with good to high enantioselectivities.
