Comparação entre a ultra-sonografia e a ressonância magnética do abdome na avaliação da morbidade na esquistossomose mansônica

Abstract

There is no study comparing ultrasonography (US) to magnetic resonance imaging (MRI) in the evaluation of liver disease in patients with schistosomiasis mansoni, except for case reports. This study compared US and MRI of the abdomen in the evaluation of morbidityin schistosomiasis mansoni. Sixty patients (age 42,1 ± 13,4 years), attending the Hospital das Clínicas UFMG, have been selected for this study. Inclusion criteria were: demonstration of schistosomal exposure through parasitological or serological techniques, or US signs of periportal fibrosis and exclusion of other causes of liver diseases. USexamination was performed using real-time ALOKA SSD 1700 device with electronic 3.5 MHz transducers. Additional imaging was obtained using a GE 1.5 T Sigma unit. Axial and coronal 7 mm slice thickness images were performed in T1 and T2-weighted sequences, before and after contrast administration. MRI presented moderate agreementwith US in the identification of periportal fibrosis. The best correlations between the two methods were observed for the detection of spleen enlargement, increase in the caliber of the portal vessels (portal, splenic and superior mesenteric veins) and thickening around the portal vein in its bifurcation and around its peripheral branches. Poor correlation wasobtained for the identification of thickening of the gallbladder wall and enlargement around the portal vein in the hepatic hilus. In the cases in which US and MRI disagreed in the identification of periportal disease, MRI revealed fat tissue where US indicated echogenic thickening suggestive of Symmers fibrosis. MRI showed that echogenicthickening around the gallbladder, even in those with advanced forms of schistosomal disease, usually corresponded to adipose tissue filling an expanded gallbladder fossa. MRI was superior to US in the identification of collateral circulation. So, this is the first study to compare US and MRI in schistosomiasis, and was the one with the largest number ofcases evaluated by MRI. For the first time it has been described that echogenic thickening around the portal vein in the hepatic hilus and around the gallbladder frequently correspond to fat tissue, and not to fibrosis. Future studies, including morphological liver analysis by MRI and histological examination, are necessary for a better understanding ofthe process of gallbladder fossa enlargement in schistosomiasis.