ABSTRACT
INTRODUCTION: To validate the use of supine position and CT images for assessing abdominal circumference (AC). METHOD: A prospective study in consecutive patients undergoing scheduled abdominal CT at our center between 17 and 25 September 2012.AC was measured four times: ·1. Standing. ·2. While lying on the CT table. ·3. On CT images with a skin contour line, using OsiriX software. ·4. On CT images with an ellipse perimeter formula, using RAIM Alma 2010 software. Measurements 1 and 2 were sequentially done by the same trained nurse before abdominal CT just above the iliac crest, while measurements 3 and 4 were done on the last abdominal CT slice not showing the iliac bone. Student's t tests and Q-Q and Bland-Altman plots were used for statistical analysis. RESULTS: A total of 102 patients were recruited. Mean age, 60 (35-78) years. Mean BMI, 25 (18-39) kg/m2. Mean AC, 93.2 (73-135) cm. No significant differences were found between the four ACs measured (Student's t test, P = 0.83). Q-Q and Bland-Altman plots showed good overlapping for the low and central values (73-110 cm) with a greater scatter for extremely high values. For the ellipse estimation, R2 was 0.987 with a mean error of 0.4 cm and a stretch dispersion between 1.1 and -0.3 cm. Conclusion Supine (either measured or estimated on CT images by free hand elliptical ROI or ellipse formula) and standing measurements appear to be equivalent for abdominal circumferences < 110 cm
OBJETIVO: Validar el uso de la posición supina y de imágenes de TAC para la evaluación de la circunferencia abdominal (AC). MÉTODO: Estudio prospectivo de pacientes consecutivos sometidos a TAC abdominal programada en nuestro centro entre el 17-25 de septiembre de 2012. La AC se midió 4 veces: ·1. Bipedestación. ·2. Posición supina sobre la mesa de TAC. ·3. En imágenes de TAC con una línea siguiendo el contorno de la piel. ·4. En imágenes de TAC mediante la fórmula del perímetro de la elipse. Las mediciones 1 y 2 se realizaron por el mismo enfermero de manera secuencial antes de la TAC abdominal, justo por encima de la cresta ilíaca, y las mediciones 3 y 4 en imágenes TAC, en el último corte por encima de la cresta ilíaca. Se utilizaron los test de «t» de Student, Q-Q y Bland y Altman. RESULTADOS: Se incluyeron 102 pacientes. La edad media fue de 60 años (35-78), el IMC medio de 25 kg/m2 (18-39), y la AC media de 93,2 cm (73-135). No se encontraron diferencias significativas entre los 4 AC medidos («t» de Student p = 0,83). En los análisis Q-Q y Bland-Altman se encontró para las 4 mediciones un buen solapamiento de los valores bajos y centrales (73-110 cm), con una mayor dispersión para los valores muy altos. Hubo muy buena correlación entre AC en bipedestación y estimado mediante el perímetro elíptico (R = 0,987), con media de error de 0,4 cm y dispersión de -0,3-1,1 cm. CONCLUSIÓN: La medición de la AC en bipedestación y en decúbito supino (ya sea medida o estimada en imágenes de TAC) parece ser equivalente para perímetros abdominales < 110 cm
Subject(s)
Humans , Waist-Hip Ratio , Abdominal Circumference , Nutrition Assessment , Obesity/diagnosis , Retrospective Studies , Prospective StudiesABSTRACT
INTRODUCTION: To validate the use of supine position and CT images for assessing abdominal circumference (AC). METHOD: A prospective study in consecutive patients undergoing scheduled abdominal CT at our center between 17 and 25 September 2012. AC was measured four times: Measurements 1 and 2 were sequentially done by the same trained nurse before abdominal CT just above the iliac crest, while measurements 3 and 4 were done on the last abdominal CT slice not showing the iliac bone. Student's t tests and Q-Q and Bland-Altman plots were used for statistical analysis. RESULTS: A total of 102 patients were recruited. Mean age, 60 (35-78) years. Mean BMI, 25 (18-39) kg/m(2). Mean AC, 93.2 (73-135) cm. No significant differences were found between the four ACs measured (Student's t test, P=0.83). Q-Q and Bland-Altman plots showed good overlapping for the low and central values (73-110 cm) with a greater scatter for extremely high values. For the ellipse estimation, R(2) was 0.987 with a mean error of 0.4 cm and a stretch dispersion between 1.1 and -0.3 cm. CONCLUSION: Supine (either measured or estimated on CT images by free hand elliptical ROI or ellipse formula) and standing measurements appear to be equivalent for abdominal circumferences <110 cm.
Subject(s)
Tomography, X-Ray Computed , Waist Circumference , Adult , Aged , Body Weights and Measures/methods , Female , Humans , Male , Middle Aged , Prospective Studies , Retrospective StudiesABSTRACT
Vasculitis is a destructive inflammatory process affecting blood vessels. Pulmonary vasculitis may develop secondary to other conditions or constitute a primary idiopathic disorder. Thoracic involvement is most common in primary idiopathic large-vessel vasculitides (Takayasu arteritis, giant cell arteritis, Behçet disease) and primary antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitides (Wegener granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome). Primary pulmonary vasculitides are rare, and their signs and symptoms are nonspecific, overlapping with those of infections, connective tissue diseases, and malignancies. The radiologic findings in primary pulmonary vasculitis vary widely and can include vessel wall thickening, nodular or cavitary lesions, ground-glass opacities, and consolidations, among others. Diffuse alveolar hemorrhage usually results from primary small-vessel vasculitis in the lungs. To diagnose vasculitis, medical teams must recognize characteristic combinations of clinical, radiologic, laboratory, and histopathologic features.
Subject(s)
Lung Diseases/diagnosis , Vasculitis/diagnosis , Behcet Syndrome/diagnosis , Contrast Media , Giant Cell Arteritis/diagnosis , Granulomatosis with Polyangiitis/diagnosis , Humans , Lung/blood supply , Lung Diseases/diagnostic imaging , Lung Diseases/pathology , Magnetic Resonance Angiography/methods , Radiographic Image Enhancement/methods , Takayasu Arteritis/diagnosis , Tomography, X-Ray Computed/methodsABSTRACT
Quarter-wave retardation can be achieved in optical tunneling through a low-index thin film that is surrounded by a medium of higher refractive index, for any index ratio N>2.414, over a range of incidence angles that is determined by N. A novel frustrated-total-internal-reflection circular polarization beam splitter (CPBS) is proposed that uses an adjustable air gap between two Ge prisms. This tunable CPBS operates over a broad (2-12 microm) IR spectral range by controlling the air-gap thickness to match one-tenth of the wavelength of light by use of a piezoelectric transducer.
ABSTRACT
An achromatic infrared (lambda = 1.2-4 microm), Si-prism quarter-wave retarder (QWR) is described that uses total internal reflection at a buried Si-SiO2 interface at an angle of incidence phi near 33 degrees, where deltaDelta/deltaphi = 0. The retardance delta deviates from 90 degrees by < +/- 2 degrees within a field of view of +/- 10 degrees (in air) over the entire bandwidth. Because the SiO2 layer at the base of the prism is optically thick, this QWR is unaffected by environmental contamination.
