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Purpose: The purpose of our study was to compare signal characteristics and image qualities of MR imaging at 3.0T and 1.5T in patients with diffuse parenchymal liver disease., Materials and Methods: 25 consecutive patients with diffuse parenchymal liver disease underwent abdominal MR imaging at both 3.0T and 1.5T within a 6-month interval. A retrospective study was conducted to obtain quantitative and qualitative data from both 3.0T and 1.5T MRI. Quantitative image analysis was performed by measuring the signal-to-noise ratios (SNRs) and the contrast-to-noise ratios (CNRs) by the Students t-test. Qualitative image analysis was assessed by grading each sequence on a 3- and 4-point scale, regarding the presence of artifacts and image quality, respectively. Statistical analysis consisted of the Wilcoxon signed-rank test., Results: the mean SNRs and CNRs of the liver parenchyma and the portal vein were significantly higher at 3.0T than at 1.5T on portal and equilibrium phases of volumetric interpolated breath-hold examination (VIBE) images (P<0.05). The mean SNRs were significantly higher at 3.0T than at 1.5T on T1-weighted spoiled gradient echo (SGE) images (P<0.05). However, there were no significantly differences on T2-weighted short-inversion-time inversion recovery (STIR) images. Overall image qualities of the 1.5T non-contrast T1- and T2-weighted sequences were significantly better than 3.0T (P<0.01). In contrast, overall image quality of the 3.0T post-gadolinium VIBE sequence was significantly better than 1.5T (P<0.01)., Conclusions: MR imaging of post-gadolinium VIBE sequence at 3.0T has quantitative and qualitative advantages of evaluating for diffuse parenchymal liver disease.

Purpose: To evaluate magnetic resonance imaging (MRI) findings of nonalcoholic steatohepatitis (NASH) and to determine the correlation of MRI findings with histopathology and Mayo End-Stage Liver Disease (MELD) score., Materials and Methods: Thirty patients (18 males, 12 females; mean age: 57+/-8.9 years; age range: 35-71 years) with histopathologically proven NASH who underwent MRI examinations between January 2001 and October 2005 were included in the study. Two radiologists retrospectively reviewed all magnetic resonance (MR) examinations in consensus to evaluate the presence and extent of predetermined findings of NASH including liver steatosis, early patchy liver enhancement indicating inflammation and liver fibrosis. The findings detected on MRI were correlated and compared to histopathological findings and MELD score by using nonparametric Spearman correlation coefficient and Kruskal-Wallis analysis of variance., Results: Liver steatosis was observed in 10 of 30 patients; early patchy liver enhancement, in 8 of 30 patients and liver fibrosis in 19 of 30 patients on MR images. Liver fibrosis was reticular in all these patients. There were statistically significant moderate correlations between MRI findings of liver steatosis and histopathologic grades of steatosis (r=0.43; P<.05), and between MRI findings of fibrosis and histopathologic stages of fibrosis (r=0.61; P<.001). Early patchy enhancement did not demonstrate statistically significant correlation with inflammation (P=.28). There was no statistically significant overall correlation between MRI findings of NASH and MELD score., Conclusion: MRI findings of liver steatosis and fibrosis in NASH showed moderate correlations with histopathologic grades of steatosis and stages of fibrosis, but MRI findings of NASH did not demonstrate any significant correlations with MELD score.

Purpose: To evaluate liver alterations caused by biliary obstruction and drainage., Methods: Thirty-nine male Wistar rats were randomly distributed in 4 groups: BO (n=18) bile duct ligation for 20 days, with a periodic evaluation of liver histological alterations, Doppler echography portal flow and measurements of NO and malondialdehyde (MDA); BO/DB (n=13) bile duct occlusion for 20 days followed by biliary drainage by choledochoduodenal anastomosis, 5 days follow-up, same BO group parameters evaluations; group CED (n=4) sham operation and portal flow evaluation trough 20 days; CHB (n=4) sham operation, with hepatic biopsy on 25th day and followed-up trough 25 days, by the same parameters of group BO, with exception of portal flow. Direct bilirubin (DB) and alkaline phosphatase (AP) were evaluated in the group BO, BO/DB and CHB., Results: The bile duct ligation led to an increase of DB and AP, development of liver histological alterations, reduction of portal flow and increase of plasmatic NO and of MDA levels. The bile duct clearing resulted in a reduction of DB, AP, NO, MDA histological alterations and increase of portal flow., Conclusion: The biliary occlusion resulted in cholestasis and portal flow reduction, besides the increase of plasmatic NO and of hepatic MDA levels, and histological liver alterations, with a tendency of normalization after the bile duct clearing.

Quantification of liver iron concentration (LIC) is crucial in the management of patients suffering from certain pathologies that can produce iron overload, such as Cooley's anemia and hemochromatosis. All of these patients must control the level of iron deposits in their organs to avoid the toxicity of high LIC, which is potentially lethal. This paper describes experimental protocols for LIC measurement using two magnetic techniques: magnetic resonance imaging (MRI) and biomagnetic liver susceptometry (BLS). MRI proton transverse relaxation rate (R2) and image intensity, evaluated pixel by pixel, were used as indicators of iron load in the tissue. LIC measurement by BLS was performed using an AC superconducting susceptometer system. A group of 23 patients with a large range of iron overload (0.9 to 34.5 mgFe/g(dry tissue)) was evaluated with both techniques (MRI x BLS). A significant linear correlation (r = 0.89-0.95) was found between the LIC by MRI and by BLS. These results show the feasibility of using two noninvasive methodologies to evaluate liver iron store in a large concentration range. Both methodologies represent an equivalent precision.

Among the few non-invasive methods to quantify liver iron deposits, magnetic resonance imaging (MRI) and biomagnetic liver susceptometry (BLS) have been considered the best to evaluate iron overload in the body. This diagnosis is necessary for patients who regularly receive red blood cells transfusion and that have a genetic disorder known as hemochromatosis. In this work, we present the evaluation of the clinical usefulness of MRI and BLS of hepatic tissue to quantify iron deposits in non-transfused and transfused patients. Liver iron evaluation by MRI and BLS were performed in a group of 48 patients. The MRI images weighted in T2 were acquired using multi-slice single-spin-echo (SSE) and single-slice multi-spin-echo (MSE), conducted on a 1.5 T whole body scanner. BLS measurements were performed using an ac superconducting susceptometer based on SQUID. Typically MRI is able to evaluate iron overload in liver as high as 30 mg/g(dry tissue) when using MRI scanners provided with specially designed pulse sequences. For higher iron concentrations susceptibility measurement works better than MRI to evaluate higher iron overloads in the liver, because in this case there is saturation of MRI signal.