Diffusion-weighted Imaging Magnetic Resonance for Assessing Liver Fibrosis

Diffusion-weighted Imaging Magnetic Resonance for Assessing Liver Fibrosis in Patients With Chronic Viral Hepatitis

Several noninvasive radiological techniques have been investigated for the diagnosis of liver fibrosis and cirrhosis among patients with chronic infection with hepatitis B virus or hepatitis C virus. Diffusion-weighted magnetic resonance imaging (DW-MRI) is a particularly appealing method for the diagnosis of liver fibrosis. The aims of this study are to evaluate the accuracy of DW-MRI in patients with chronic viral hepatitis for determining the stage of liver fibrosis.

Among patients with chronic infection with hepatitis B virus or hepatitis C virus, evaluation of the stage of liver fibrosis is of major importance for determining prognosis and therapeutic decisions. Liver biopsy is a costly and invasive technique with associated mortality and morbidity. A typical biopsy fragment represents only 1/50,000 of the organ. Several noninvasive radiological techniques have been investigated for the diagnosis of liver fibrosis and cirrhosis. Diffusion-weighted magnetic resonance imaging (DW-MRI) is a particularly appealing method for the diagnosis of liver fibrosis. Because it is easy to implement, non-operator dependent, and process without the need for contrast agents. However, preliminary studies on small numbers of patients in which various hardware and sequencing profiles were used have reported inconsistent results for staging liver fibrosis with DW-MRI. The aims of this study are to evaluate correlation between stage of hepatic fibrosis and liver apparent diffusion coefficient (ADC) and normalized liver ADC with spleen assessed by DW-MRI in patients with chronic viral hepatitis B or C. Also, this study aim to evaluate factors that influence liver ADC and normalized liver ADC with spleen value for predicting the stage of liver fibrosis as well as to estimate the optimal cutoff values of DW-MRI for determining significant liver fibrosis (fibrosis stage ≥2) and advanced fibrosis (fibrosis stage ≥3).

Magnetic resonance (MR) imaging examination of liver will be performed on a 3.0T Achieva MR scanner (Philips Medical Systems, The Netherlands). Diffusion-weighted imaging (DWI) will be performed using a single-shot echo-planar imaging during a single end expiratory breath-hold. A single observer placed circular regions of interest around 2.30 cm2 to measure mean signal intensity (SI) in the right hepatic lobe and the spleen for each b value, avoiding areas of artifact, vessels, and focal lesions. A monoexponential fit will be performed to calculate liver and spleen apparent diffusion coefficient (ADC) on the basis of ln(SI) as a function of b value, using all b values. Normalized liver ADC will be calculated as the ratio of liver ADC to spleen ADC.

Magnetic resonance (MR) imaging examination of liver will be performed on a 3.0T Achieva MR scanner (Philips Medical Systems, The Netherlands). Diffusion-weighted imaging (DWI) will be performed using a single-shot echo-planar imaging during a single end expiratory breath-hold. A single observer placed circular regions of interest around 2.30 cm2 to measure mean signal intensity (SI) in the right hepatic lobe and the spleen for each b value, avoiding areas of artifact, vessels, and focal lesions. A monoexponential fit will be performed to calculate liver and spleen apparent diffusion coefficient (ADC) on the basis of ln(SI) as a function of b value, using all b values. Normalized liver ADC will be calculated as the ratio of liver ADC to spleen ADC.

The correlation coefficient of the stage of hepatic fibrosis and liver apparent diffusion coefficient as assessed by DW-MRI

The primary aim of this study is to evaluate correlation between stage of hepatic fibrosis and liver apparent diffusion coefficient (ADC) and normalized liver ADC with spleen assessed by DW-MRI in patients with chronic viral hepatitis B or C.

The aim of this study is to estimate the optimal cutoff values of DW-MRI for determining significant liver fibrosis (fibrosis stage ≥2) and advanced fibrosis (fibrosis stage ≥3).

The effects of hepatic steatosis, necroinflammation and hepatic iron on ADC values for determining the stage of liver fibrosis

The aim of this study is to evaluate whether the degree of hepatic steatosis, necroinflammation, and hepatic iron affect the values of liver ADC and normalized liver ADC with spleen for determining the stage of liver fibrosis.

Inclusion Criteria: All naive patients with chronic hepatitis B or C infection who undergo liver biopsy examination for evaluating candidates for antiviral therapy will be invited to participate into this study Exclusion Criteria: Other cause of chronic liver disease Contraindication for liver biopsy Contraindication for magnetic resonance imaging

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