Diffuse Parenchymal Disease

Abstract

In this chapter, the main diffuse liver parenchyma disorders will be evaluated. The different MR approaches used to make a clear initial qualitative evaluation will be commented and complemented with the implementation of imaging biomarkers to accurately quantify the degree of liver abnormalities.

MR is unique in its ability to extract information on tissue components and functional status. This information has transformed the way imaging interacts in clinical scenarios of liver disorders. MR can accurately evaluate the degree of liver steatosis with the use of chemical shift and TSE fat suppression imaging. New tools (separation of water and fat signals with gradient asymmetric echo and spectroscopy) may be even more precise. Also, noninvasiveness of iron concentration can be now calculated with multiecho T2* relaxometry techniques and even with simple monoexponential T2 decay signal intensity calculations. The degree of water in the parenchyma can be also inferred with the use of STIR images, thereby allowing the diagnosis of esteatohepatitis and grading the necroinflammatory infiltrate in cirrhosis. The liver perfusion characteristics may also be of interest in the evaluation of fibrosis and inflammation. MR Elastography and MR Spectroscopy with metabololomic quantitation will also play a role in the grading of chronic liver diseases.

Perfusion abnormalities and vascular disorders are frequently seen with contrast enhanced MR examinations. Hepatic perfusion disorders are either primary or secondary to diffuse and focal liver lesions. MR depicts the common transient arterialization of the arterioportal shunts. Specific hepatobiliary and iron oxide particles may be necessary to clarify that an abnormal perfused area is not a real liver tumor.