Validation of 2d ultrasound and volume estimation formulae for volume assessment of kidneys and spleens: an in-vitro study / alidación de la fórmula de estimación de volumen y ultrasonido 2D para la evaluación del volumen de los riñones y el bazo: un estudio in vitro

The accuracy of internal organ volume estimation done with ultrasound (US) was found to be multifactorial. Hence, we aimed to describe and validate the volume assessment of ultrasound and standard volume estimation formulae for different shaped intra-abdominal organs using spleens and kidneys.Dissected cadaveric kidneys (n=25) and spleens (n=29) were scanned to obtain linear measurements and ultrasound auto-generated volumes (USV). Linear measurements were used to calculate the volumes manually with ellipsoid, prolate, and Lambert volume estimating formulae. The actual volumes (AV) of organs were obtained by the water displacement method. Volume assessment accuracy of USV and different formulae were compared by comparing bias, precision and Bland-Altman plot analysis. The US linear and volume measurement procedure was reliable with high inter and intra-observer agreements (linear: Chronbach's α=0.983 to 0.934; volumes: Chronbach's α=0.989). USV estimates were accurate with a high correlation to AV and low estimation bias (-5.9%). Also, prolate (bias=-0.75%) and ellipsoid formulae (bias=-3.75%) were reliable with a negligible bias in estimated volumes. Contrary, the Lambert formula was unreliable due to a high bias (41.6%). For all evaluated methods, the estimation error found to be related to the organ size (T=3.483; p=0.001), mainly when the assessed organ is larger than 50 ml. Also, the shape related estimation error found to be related to the volume estimation formula used.This study has validated the USV for kidney and splenic volume assessments while describing volume-calculating formula employed, organ size and shape as significant contributors for volume estimation accuracy.

Se encontró que la precisión de la estimación del volumen de órganos internos realizada con ultrasonido (US) es multifactorial. El objetivo fue describir y validar la evaluación de volumen mediante ecografía y las fórmulas estándar de estimación de volumen para órganos intraabdominales de diferentes formas utilizando bazos y riñones.Se evaluaron riñones cadavéricos disecados (n = 25) y bazos (n = 29) para obtener medidas lineales y volúmenes autogenerados por ultrasonido (USV). Se utilizaron medidas lineales para calcular los volúmenes manualmente con fórmulas de estimación de volumen elipsoide, prolate y Lambert. Los volúmenes reales (AV) de los órganos se obtuvieron mediante el método de desplazamiento de agua. Se comparó la precisión de la evaluación del volumen de USV y diferentes fórmulas comparando el sesgo, la precisión y el análisis de la gráfica de Bland-Altman. El procedimiento de medición lineal y de volumen mediante US fue confiable con alta concordancia inter e intraobservadores (lineal: α de Chronbach = 0,983 a 0,934; volúmenes: α de Chronbach = 0,989). Las estimaciones de USV fueron precisas con una alta correlación con AV y un bajo sesgo de estimación (-5,9%). Además, las fórmulas prolate (sesgo= -0,75%) y elipsoide (sesgo = -3,75%) fueron confiables con un sesgo insignificante en los volúmenes estimados. Por el contrario, la fórmula de Lambert no fue confiable debido a un alto sesgo (41,6%). Para todos los métodos evaluados, se encontró que el error de estimación estaba relacionado con el tamaño del órgano (T = 3.483; p = 0.001), principalmente cuando el órgano evaluado es mayor de 50 ml. Además, se encontró que el error de estimación de forma está relacionado con la fórmula de estimación de volumen utilizada.Este estudio ha validado el USV para evaluaciones de volumen renal y esplénico al mismo tiempo que describe la fórmula de cálculo de volumen empleada, el tamaño y la forma de los órganos como contribuyentes significativos de la precisión de la estimación de volumen.

Effects of maternal and postweaning high-fat diet exposure on the hippocampal functions and morphology / Efectos de la exposición de la dieta alta en grasa materna y pos lactancia en la función del hipocampo y la morfología

Unbalanced nutrition during perinatal period causes varying degrees of perturbations in the metabolism and cognitive functions of offspring. The aim of this study was to investigate effects of maternal and postweaning high-fat diet (HFD) exposure on the growth parameters, hippocampal functions and morphology of offspring in a sex-dependent manner. Spraque-Dawley rats were fed either standard (10 % fat) or saturated-fat (65 % fat) diet during their gestation and lactation period. After weaning, pups were sustained in same diet for 6 more weeks. Body mass index (BMI) of pups were monitored weekly, then spontaneous locomotor activities were recorded. Spatial learning and memory functions were analyzed by Morris Water Maze (MWM) test. Total volumetric changes of hippocampal subfields were estimated by Cavalieri method. HFD exposure produced sex-dependent alterations in BMI, serum lipid and activity levels. MWM results showed no significant difference among groups. However, retrieval indexes were higher in HFD-fed males. Total volumetric analysis of the dentate gyrus was comparable, but the pyramidal cell layer volume of HFD-fed males was lower than those of SD-fed males. Despite alterations in some growth and lipid parameters, maternal and perinatal exposure to HFD did not markedly affect cognitive functions and hippocampal morphology of offspring.

La nutrición desequilibrada durante el período perinatal causa diversos grados de perturbaciones en el metabolismo y las funciones cognitivas en neonatos. El objetivo de este estudio fue investigar los efectos de la exposición a una dieta alta en grasas (HFD) materna y posdestete en los parámetros de crecimiento, las funciones del hipocampo y la morfología de neonatos de una manera dependiente del sexo. Ratas SpragueDawley fueron alimentadas con dieta estándar (10 % grasa) o grasa saturada (65 % grasa) durante su período de gestación y lactancia. Después del destete, las crías se mantuvieron en la misma dieta durante 6 semanas. El índice de masa corporal (IMC) de las crías se controló semanalmente, luego se registraron las actividades locomotoras espontáneas. El aprendizaje espacial y las funciones de memoria se analizaron mediante la prueba Morris Water Maze (MWM). Los cambios volumétricos totales de los subcampos del hipocampo se estimaron mediante el método de Cavalieri. La exposición a HFD produjo alteraciones dependientes del sexo en el IMC, los niveles de lípidos séricos y los niveles de actividad. Los resultados de MWM no mostraron diferencias significativas entre los grupos. Sin embargo, los índices de recuperación fueron más altos en machos alimentados con HFD. El análisis volumétrico total del giro dentado fue comparable, pero el volumen de la capa de células piramidales de los machos alimentados con HFD fue menor que el de los machos alimentados con SD. A pesar de las alteraciones en algunos parámetros lipídicos y de crecimiento, la exposición materna y perinatal a HFD no afectó marcadamente las funciones cognitivas y la morfología del hipocampo de la descendencia.

Ultrasonographic quantification of pleural effusion: comparison of four formulae

PURPOSE: The purpose of this study was to evaluate the correlations of ultrasonographically estimated volumes of pleural fluid with the actual effusion volume in order to determine the most reliable formula. METHODS: In 32 consecutive patients with clinically diagnosed pleural effusion, an ultrasound estimation was made of the volume of effusion using four different formulae, including two in the erect position and two in the supine position. Closed-tube thoracostomy drainage using a 28-Fr chest tube was performed. The total drainage was calculated after confirmation of full lung re-expansion and complete drainage by plain chest radiographs and ultrasound. The ultrasonographically estimated volume was compared to the actual total volume drained as the gold standard. RESULTS: There were 14 female and 18 male subjects. The mean age of all subjects was 41.56±18.34 years. Fifty percent of the effusions were in the left hemithorax. Metastatic disease accounted for the plurality of effusions (31.2%). The mean total volume drained for all the subjects was 2,770±1,841 mL. The ultrasonographically estimated volumes for the erect 1, erect 2, supine 1, and supine 2 formulae were 1,816±753 mL, 1,520±690 mL, 2,491±1,855 mL, and 1,393±787 mL, respectively. The Pearson correlation coefficients (r) for the estimate of each formula were 0.75, 0.81, 0.62, and 0.63, respectively. CONCLUSION: Although both erect formulae showed similar correlations, the erect 2 formula (Goecke 2) was most closely correlated with the actual volume drained.

Sampling procedures for inventory of commercial volume tree species in Amazon Forest

ABSTRACT The spatial distribution of tropical tree species can affect the consistency of the estimators in commercial forest inventories, therefore, appropriate sampling procedures are required to survey species with different spatial patterns in the Amazon Forest. For this, the present study aims to evaluate the conventional sampling procedures and introduce the adaptive cluster sampling for volumetric inventories of Amazonian tree species, considering the hypotheses that the density, the spatial distribution and the zero-plots affect the consistency of the estimators, and that the adaptive cluster sampling allows to obtain more accurate volumetric estimation. We use data from a census carried out in Jamari National Forest, Brazil, where trees with diameters equal to or higher than 40 cm were measured in 1,355 plots. Species with different spatial patterns were selected and sampled with simple random sampling, systematic sampling, linear cluster sampling and adaptive cluster sampling, whereby the accuracy of the volumetric estimation and presence of zero-plots were evaluated. The sampling procedures applied to species were affected by the low density of trees and the large number of zero-plots, wherein the adaptive clusters allowed concentrating the sampling effort in plots with trees and, thus, agglutinating more representative samples to estimate the commercial volume.