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Nonalcoholic fatty liver disease (NAFLD) has become one of the most common causes of chronic liver disease. If NAFLD and chronic viral hepatitis remain untreated, patients gradually develop liver fibrosis further progressing to cirrhosis. Significant advances in magnetic resonance imaging (MRI) and MR elastography allow quantification of hepatic steatosis and fibrosis before end-stage liver disease and emerge as noninvasive screening and monitoring tools as an alternative to liver biopsy (Dulai et al. J Hepatol. 65(5):1006–1016, 2016). Cirrhosis is characterized by progressive fibrosis of the liver parenchyma with ongoing regeneration. However, at an early stage of cirrhosis, the liver may appear normal. Patients with cirrhosis are not only at risk of liver failure but also at risk to develop hepatocellular carcinoma (HCC) and intrahepatic cholangiocellular carcinoma.

HCC in cirrhosis either develops in a stepwise carcinogenesis from regenerative nodules to low-grade dysplastic nodule, high-grade dysplastic nodule, and HCC or develops de novo. To facilitate and standardize the categorization of these cirrhotic nodules seen in patients at risk for HCC along a spectrum from benign to malignant, the Liver Imaging Reporting and Data System (LI-RADS) provides a diagnostic algorithm for analysis of cross-sectional images (Santillan et al. Magn Reson Imaging Clin N Am. 22(3):337–352, 2014). HCC differs from most malignancies because it is commonly diagnosed on the basis of imaging features alone, without histological confirmation.

Vascular liver disease such as arterioportal shunts may be difficult to distinguish from HCC. Diffuse parenchymal alteration seen in Budd-Chiari syndrome with large hypervascular regenerative nodules can be mistaken for HCC. Portal vein thrombosis occurs in the setting of cirrhosis and HCC and either appears as bland thrombus or tumor thrombus.

The incidence of diffuse liver disease, including all causes, is increasing worldwide. On one side this is due to trends in population towards aging and obesity resulting in a higher prevalence of steatosis/steatohepatitis, fibrosis, and cirrhosis. On the other side, inflammatory origin, especially due to viral hepatitis, is one of the primary reasons for diffuse liver disease. This chapter will describe the most common imaging features of hepatic metabolic and storage diseases, including overload with fat, iron, copper, and amyloid and diffuse neoplastic diseases. We also discuss focal and diffuse infectious and inflammatory hepatic diseases. Key imaging manifestations of fungal, granulomatous, parasitic, viral, and bacterial as well as the less common hepatic infections such as cat-scratch disease, bacillary angiomatosis, and amebic disease are reviewed to avoid pitfalls in image interpretation. Although magnetic resonance imaging (MRI) provides unique capabilities for noninvasive and quantitative characterization of liver tissue that rival the diagnostic utility of liver biopsies, also characteristic imaging findings with computed tomography (CT) that are useful in daily clinical routine will be discussed.

MRI plays an important protocol in the diagnostic work-up of patients with various inflammatory and obstructive urogenital pathologies. In obstructions caused by calculi or urogenital emergencies, CT is the sectional imaging modality of choice. Here, MRI is important as a secondary method to detect other underlying causes of obstruction such as urogenital malignancies. The standard protocol should consist of T1- and T2-weighted sequence with and without fat saturation as well as dynamic contrast-enhanced sequences including late urographic phases and is usually flanked by modern “functional” techniques (e.g., diffusion-weighted imaging (DWI) and/or dynamic contrast-enhanced imaging (DCE)) to increase the specificity of the examination and to detect complications (e.g., abscess formation).

For many radiologists, requests for imaging evaluation of testicular or scrotal symptoms and physical exam findings may cause some degree of uneasiness, for two main reasons: first, the number of tumor entities and tumor-like lesions in the testes and scrotum is relatively large and their histopathologic classification is complex (Table 1) and second, case volume of scrotal studies for non-emergency indications may be relatively low in some centers. In this chapter, we provide basic strategies to extract information from imaging pertinent to some of the most commonly encountered clinical scenarios in the evaluation of the testes and scrotum.