RESUMEN
OBJECTIVE: To examine five available software packages for the assessment of abdominal adipose tissue with magnetic resonance imaging, compare their features and assess the reliability of measurement results. DESIGN: Feature evaluation and test-retest reliability of softwares (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision) used in manual, semi-automated or automated segmentation of abdominal adipose tissue. SUBJECTS: A random sample of 15 obese adults with type 2 diabetes. MEASUREMENTS: Axial T1-weighted spin echo images centered at vertebral bodies of L2-L3 were acquired at 1.5 T. Five software packages were evaluated (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision), comparing manual, semi-automated and automated segmentation approaches. Images were segmented into cross-sectional area (CSA), and the areas of visceral (VAT) and subcutaneous adipose tissue (SAT). Ease of learning and use and the design of the graphical user interface (GUI) were rated. Intra-observer accuracy and agreement between the software packages were calculated using intra-class correlation. Intra-class correlation coefficient was used to obtain test-retest reliability. RESULTS: Three of the five evaluated programs offered a semi-automated technique to segment the images based on histogram values or a user-defined threshold. One software package allowed manual delineation only. One fully automated program demonstrated the drawbacks of uncritical automated processing. The semi-automated approaches reduced variability and measurement error, and improved reproducibility. There was no significant difference in the intra-observer agreement in SAT and CSA. The VAT measurements showed significantly lower test-retest reliability. There were some differences between the software packages in qualitative aspects, such as user friendliness. CONCLUSION: Four out of five packages provided essentially the same results with respect to the inter- and intra-rater reproducibility. Our results using SliceOmatic, Analyze or NIHImage were comparable and could be used interchangeably. Newly developed fully automated approaches should be compared to one of the examined software packages.
Asunto(s)
Grasa Abdominal/patología , Diagnóstico por Imagen/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Obesidad/diagnóstico , Validación de Programas de Computación , Anciano , Diagnóstico por Imagen/normas , Femenino , Humanos , Imagen por Resonancia Magnética/normas , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Reproducibilidad de los ResultadosRESUMEN
Breath biomarkers have the potential to offer information that is similar to conventional clinical tests or they are entirely unique. Preliminary data support the use of breath biomarkers in the study of liver disease, in particular non-alcoholic fatty liver disease (NAFLD). It was evaluated whether breath ethanol, ethane, sulfur compounds and acetone would be associated with hepatic histopathology amongst morbidly obese patients presenting for bariatric surgery. Breath samples were collected during a preoperative visit and compared with liver biopsies obtained during the surgery. A Student's two-tailed t-test was used to compare differences between the two groups. Linear regression was used to analyse associations between the concentrations of breath molecules and independent predictor variables. It was found that breath ethanol, ethane and acetone can be useful biomarkers in patients with NAFLD. In particular, breath ethanol can be associated with hepatic steatosis, and breath acetone can be associated with non-alcoholic steatohepatitis.
Asunto(s)
Biomarcadores/análisis , Pruebas Respiratorias , Hígado Graso/metabolismo , Acetona/análisis , Adulto , Dióxido de Carbono/análisis , Etanol/análisis , Femenino , Humanos , Masculino , Persona de Mediana Edad , Azufre/análisisRESUMEN
Scleroderma (systemic sclerosis) is a chronic multisystem autoimmune disease in which oxidative stress is suspected to play a role in the pathophysiology. Therefore, it was postulated that patients with scleroderma would have abnormally high breath ethane concentrations, which is a volatile product of free-radical-mediated lipid peroxidation, compared with a group of controls. There was a significant difference (p<0.05) between the mean exhaled ethane concentration of 5.27 pmol ml(-1) CO(2) (SEM=0.76) in the scleroderma patients (n=36) versus the mean exhaled concentration of 2.72 pmol ml(-1) CO(2) (SEM=0.71) in a group of healthy controls (n=21). Within the scleroderma group, those subjects taking a calcium channel blocker had lower ethane concentrations compared with patients who were not taking these drugs (p=0.05). There was a significant inverse association between lung diffusion capacity for carbon monoxide (per cent of predicted) and ethane concentration (b=-2.8, p=0.026, CI=-5.2 to -0.35). These data support the presence of increased oxidative stress among patients with scleroderma that is detected by measuring breath ethane concentrations.
Asunto(s)
Etano/análisis , Esclerodermia Sistémica/fisiopatología , Pruebas Respiratorias , Etanol/análisis , Humanos , Peroxidación de Lípido , Mediciones del Volumen Pulmonar , Persona de Mediana EdadRESUMEN
Hepatic encephalopathy (HE) is a common and dreaded complication of liver disease. The effects of HE can range from minimal to life threatening. Even 'minimal HE' causes major dysfunction in many aspects of daily living. The exact pathogenesis of HE remains unknown. However, the products of gut flora metabolism are universally recognized as critical. Present treatments for HE include the cathartic agent lactulose and poorly absorbable antibiotics. While effective, these treatments incur numerous side-effects and cost. Probiotics are viable bacteria given orally to improve health. Probiotics have multiple mechanisms of action that could disrupt the pathogenesis of HE and may make them superior to conventional treatment.