Diagnostic performance of a rapid magnetic resonance imaging method of measuring hepatic steatosis

Objectives: Hepatic steatosis is associated with an increased risk of developing serious liver disease and other clinical sequelae of the metabolic syndrome. However, visual estimates of steatosis from histological sections of biopsy samples are subjective and reliant on an invasive procedure with associated risks. The aim of this study was to test the ability of a rapid, routinely available, magnetic resonance imaging (MRI) method to diagnose clinically relevant grades of hepatic steatosis in a cohort of patients with diverse liver diseases. Materials and Methods: Fifty-nine patients with a range of liver diseases underwent liver biopsy and MRI. Hepatic steatosis was quantified firstly using an opposed-phase, in-phase gradient echo, single breath-hold MRI methodology and secondly, using liver biopsy with visual estimation by a histopathologist and by computer-assisted morphometric image analysis. The area under the receiver operating characteristic (ROC) curve was used to assess the diagnostic performance of the MRI method against the biopsy observations. Results: The MRI approach had high sensitivity and specificity at all hepatic steatosis thresholds. Areas under ROC curves were 0.962, 0.993, and 0.972 at thresholds of 5%, 33%, and 66% liver fat, respectively. MRI measurements were strongly associated with visual (r2 = 0.83) and computer-assisted morphometric (r2 = 0.84) estimates of hepatic steatosis from histological specimens. Conclusions: This MRI approach, using a conventional, rapid, gradient echo method, has high sensitivity and specificity for diagnosing liver fat at all grades of steatosis in a cohort with a range of liver diseases

A nicotina atua como fator deletério na reparação da parede abdominal The nicotine has a deleterious effect on the healing of abdominal wall

OBJETIVO: Avaliar o efeito da nicotina na cicatrização da camada musculoaponeurótica da parede abdominal. MÉTODOS: Estudo experimental em que foram usados 16 ratos da raça Wistar pesando em média 210&plusmn; 8g, separados aleatoriamente em 2 grupos de 8. Nos animais do grupo A foi implantado disco de nicotina (Nicotinel Ò) na dose de 5mg/Kg de peso/dia no subcutâneo da região dorsal, trocado a cada dois dias, a partir do 5&ordm; dia antes da operação em que foi feita laparotomia mediana de 5 cm, até o 10º dia de observação. No grupo B (controle) foram usados discos de celulose com o mesmo diâmetro. Tubo de silicone multiperfurado foi implantado no subcutâneo a 1cm da lesão da parede abdominal. A camada musculoaponeurótica e a pele foram suturadas com fio de nylon 5-0. No 10&ordm; dia pós-operatório foi colhido 1ml de líquido seroso do tubo de silicone por punção percutânea para dosagem de pO2 e os animais receberam dose letal de anestésico. Foi ressecado um segmento da camada musculoaponeurótica com 2cm de largura para tensiometria, em seguida processado e corado em HE e tricrômico de Masson para análise quantitativa dos dados histopatológicos em sistema digitalizado. A análise estatística foi feita pelo ANOVA e teste Newman-Keuls, com significância 0,05. RESULTADOS: No grupo A a pO2 do líquido tecidual atingiu o valor 17,75&plusmn; 3,4 mmHg e no grupo B (controle) a pO2 = 40,75&plusmn; 6,4 mmHg (p<0,01). A resistência à tensão apresentou o valor de 728,5&plusmn; 161,75gf no grupo A e 1241,6&plusmn; 232gf no grupo de controle (p<0,01), coincidindo com os achados da pO2. A densidade média dos elementos histopatológicos estudados foi de 105&plusmn; 17,1 nos animais do grupo A e 146,2&plusmn; 8,8 no grupo B (p<0,01). CONCLUSÃO: após avaliação da pO2 tecidual, tensiometria e histopatologia, concluiu-se que a nicotina por via subcutânea exerce efeito deletério sobre a cicatrização de lesões da parede abdominal de ratos.<br>OBJETIVE: An experimental study was done to evaluate the effect of nicotine on the healing of abdominal wall. METHODS: Sexteen Wistar rats weighing 210&plusmn; 8g were randomly separated into two groups of eight rats each. In the group A Nicotine (Nicotinel Ò) was implanted in the back subcutaneous 5mg/Kg each two days, begining at the fifth preoperative day. A 5cm median laparotomy was done, sutured with nylon 5-0 and the rats were observed in individual cages. The group B (control) didn&rsquo;t use nicotine. A multiperfurated silicone tube was implanted subcutaneously near the abdominal sutured lesion. In the tenth postoperative day 1ml of serous liquid was harvested from the silicone tube and a pO2 dosage was done. The rats were killed with overdose of anesthetic. A 2cm width transversal segment of abdominal wall was submited to tensile strength test by a tensiometer. A biopsy of the sutured area including muscle, aporeurosis and peritoneum was processed for histopatologic analysis by a digitalised system. The data were processed by the ANOVA and Newman-Keuls tests, considering significant the differences when p<0,05. RESULTS: In the group A the pO2 on the tissue serous liquid reached 17,75&plusmn; 3,4 mmHg and in the group B (control) the pO2 = 40,75&plusmn; 6,4 mmHg (p<0,01). The tensile strength reached 728,5&plusmn; 161,75gf in the group A and 1241,6&plusmn; 232gf in the control one (p<0,01).The mean density of the histopatologic elements was 105&plusmn; 17,1 in group A and 146,2&plusmn; 8,8 in group B (p<0,01). CONCLUSION: after evaluation of tissue pO2 , tensiometry and histopatology, the data permited to conclude that the nicotine has a deleterious effect on the healing the abdominal wall of rats