| Summary: | <p>Liver disease is a major worldwide health problem with high prevalence and poor patient outcomes. In the last decade, efforts to improve liver disease severity assessment have led to the development of many non-invasive methods, including magnetic resonance (MR) techniques.</p> <p>The overarching aim of this thesis was to examine a multi-parametric MR technique in the evaluation of different aspects of liver disease. The MR protocol included T<sub>1</sub> and T<sub>2</sub>&ast; mapping techniques which were used to compute the iron corrected T<sub>1</sub> (cT<sub>1</sub>) and the liver inflammation and fibrosis (LIF) score as measures of liver inflammation and fibrosis. </p> <p>In healthy volunteers, it was found that premenopausal women had a higher median liver cT<sub>1</sub> (784ms) compared to postmenopausal women (741ms; p=0.038) or age matched men (742ms; p=0.005). Furthermore, blood volume was identified as the most significant physiological determinant of liver cT1 and a correction algorithm was developed to compute the "volume adjusted and iron corrected T<sub>1</sub>" (vacT<sub>1</sub>), which removes the confounding effect of liver congestion and improves the performance of the test as a biomarker of liver fibrosis.</p> <p>Against histology, liver cT<sub>1</sub> was strongly associated with liver collagen proportionate area, particularly in patients with viral hepatitis (r=0.80; p&LT;0.0001). Furthermore, liver cT<sub>1</sub> / LIF had an excellent diagnostic accuracy for the assessment of multiple aspects of non-alcoholic fatty liver disease (NAFLD) with an area under the receiver operating curve of 0.89 for the identification of significant NAFLD. </p> <p>In the evaluation of portal hypertension, liver cT<sub>1</sub> (r=0.49; p=0.038) was associated with the hepatic vein pressure gradient (HVPG), and spleen cT<sub>1</sub> was identified as a new biomarker of portal pressure (r=0.66; p&LT;0.0001 vs HVPG). Furthermore, liver cT<sub>1</sub> / LIF was shown to be useful in predicting clinical outcomes, with a negative predictive value of 100% for a LIF&LT;2. </p> <p>Overall, this thesis demonstrated multi-parametric MR to be a robust technique that can assess the whole spectrum of liver disease. </p>
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