Daniel Capucho de Oliveira

QUANTITATIVE COMPUTED TOMOGRAPHY OF THE LIVER IN JUVENILE GREEN SEA TURTLES (CHELONIA MYDAS)

Abstract:  Quantitative computed tomography (QCT) is a highly sensitive, applicable technique for determining the x-ray attenuation of organs. This technique reveals great precision in the detection of alterations in the x-ray attenuation of hepatic parenchyma, although the lack of studies establishing normal values limits its application in wild animals. The objective of this study was to establish mean hepatic attenuation values in four healthy juvenile sea turtles (Chelonia mydas) using QCT. Helical computed tomography scans were performed and regions of interest selected in the liver after multi-planar reconstruction images were obtained. The mean attenuation value for the hepatic parenchyma in these four turtles was 60.09 ± 5.3 standard deviation Hounsfield units. Determining normal x-ray attenuation values of the liver increases knowledge of the computed tomographic anatomy of this species and may be useful in the investigation of hepatic diseases.

Doppler tecidual do miocárdio de gatos submetidos à anestesia dissociativa

The tissue Doppler imaging (TDI) is a recent technique that allows the evaluation of the myocardium movement velocity during the cardiac cycle phases, providing important informations of the cardiac function. In veterinary medicine, studies have been realized for the characterization of cardiac contractility dysfunctions and to establish the normality patterns. The present work meant to evaluate the myocardium contractility velocity by the technique of TDI in healthy cats submitted to dissociative anesthesia. For that purpose, there were used nine cats, all adult, healthy and without sexual or breeding distinction. There were measured the values of Ea (early diastolic peak velocity), Aa (late diastolic peak velocity) and Sa (systolic peak velocity) in the lateral and septum wall sides. The mean values observed to septum Ea and septum Sa were of 7.2±2.5cm s-1 and 6.3±1.7cm s-1, respectively. The mean value obtained for lateral Ea was of 12.0±4.1cm s-1, while the mean value of lateral Sa was of 8.3±1.6cm s-1. It was obtained a mean value of 7.0±3.1cm s-1 for the lateral Aa, and 4.7±1.5cm s-1 for septum Aa. The standard of the myocardium contraction velocities mean values in the feline specie is of great importance, and it may help in the early diagnosis of heart contraction alterations. Due to the lack of studies with the TDI technique in cats, the values obtained in our work allow the realization of comparative studies, helping to apply this technique in experimental protocols and to the early diagnosis of cardiomyopathies in the feline specie.

Ultrassonografia quantitativa do fígado em gatos com tirotoxicose induzida

Este estudo avaliou ultrassonograficamente o figado de gatos submetidos a tirotoxicose induzida pela tecnica de histograma dos niveis de cinza com o objetivo de melhor avaliar possiveis alteracoes hepaticas decorrentes do excesso de hormonios tiroidianos. Para isto, foram utilizados nove gatos higidos, adulto-jovens, que receberam diariamente 150µg/kg de levotiroxina sodica, por 60 dias. O histograma hepatico nao demonstrou diferenca estatistica ao nivel de 5% de significância entre os momentos avaliados; entretanto, as variacoes dos valores das variaveis estudadas sugeriram a promocao de aumento da heterogeneidade e diminuicao da ecogenicidade do parenquima hepatico quando comparado ao momento inicial. A avaliacao citopatologica e histopatologica revelou quadro de hepatite tirotoxica em todos os animais.

Quantitative computed tomography of the liver in dogs submitted to prednisone therapy

The aim of this study is to evaluate the possible alterations in radiodensity of the hepatic parenchyma and spleen resulting from the corticotherapy with prednisone, correlating these findings with serum biochemical hepatic transaminase activity. A clinical trial was performed on eight healthy dogs with the intent of evaluating possible hepatic alterations after prednisone therapy using quantitative computed tomography. All animals received prednisone orally at a dose of 2mg/kg of weight for 30 days. The radiodensity of the liver and spleen was determined before and after the period that the medication was administered. An increase in the radiodensity of the hepatic parenchyma between the initial and final experimental stages was observed. In the present study the existence of early hepatic alterations were verified, which are compatible with glycogen storage.

Quantitative computed tomography of the renal cortex in healthy dogs and cats

Este estudo caracteriza a radiodensidade do cortex renal de 10 caes e 10 gatos adultos, clinicamente saudaveis, por meio de exames de tomografia computadorizada helicoidal. Em cada rim, a radiodensidade renal foi estimada pelo valor medio das tres regioes de interesse na regiao cortical, selecionados no polo cranial, polo caudal e hilo renal. A radiodensidade media do cortex renal nos caes e nos gatos foi, respectivamente, 28,4±4,7 e 22,4±3,6 unidades Hounsfield (HU). Verificou-se que os gatos possuem cortex renal hipoatenuante quando comparado com caes, um fato que esta associado a maior deposicao de conteudo lipidico nos rins felinos. A diferenca na radiodensidade encontrada entre o cortex renal de caes e de gatos e importante para uma correta interpretacao dos achados renais no exame tomografico.

Pulsed-wave tissue Doppler imaging of the myocardium of cats with induced thyrotoxicosis

Left ventricular myocardial motion was quantified using pulsed-wave tissue Doppler imaging (PW-TDI) in nine adult cats before and after thyrotoxicosis induction. In order to induce thyrotoxicosis, all cats were given 150µg kg-1 of levothyroxine sodium as a single oral dose each day for 10 weeks. PW-TDI examinations were performed immediately before the induction and by the end of the experimental protocol. An increase in myocardial motion velocity was documented at the interventricular septum level, demonstrated by an elevation in systolic (Sa), and early (Ea) and late (Aa) diastolic waves (P<0.05). However, no alteration in Sa, Ea and Aa values was seen at the lateral mitral annulus. Heart rate increased significantly between the experimental stages, and three of the animals presented fused Ea and Aa waves at the end of the experiment. The experimental protocol used in this study caused alterations in left ventricular myocardial motion velocity, but did not impair left ventricular diastolic function.

Grau de desmineralização em osso trabecular e cortical por meio de tomografia computadorizada quantitativa em cães submetidos à terapia com prednisona

Glucocorticoids are widely used in veterinary medicine. However, beyond the beneficial effects, their use can trigger a series of unwanted effects. A clinical trial was conducted in eight healthy dogs in order to assess possible changes in bone mineral density after therapy with prednisone using helical computed tomography. All animals received oral prednisone at a daily dose of 2mg kg-1 of body weight for 30 days. Bone mineral density was determined by the obtaining of radiodensity values from the cortical region and the trabecular region of the second lumbar vertebra immediately before and after the period of drug administration. The experimental protocol allowed the characterization of a significant (P<0.01) decrease of trabecular bone radiodensity on the second lumbar vertebra, but no significant demineralization was found in the cortical region. None of the dogs used in this experiment had pathological fracture at the end of the experimental protocol. This study showed that in dogs subjected to therapy with prednisone at a dose of 2mg kg-1 changes in bone metabolism occur early in trabecular bone, being recommended to monitor these patients for the prevention of pathologic fractures.