However, unlike the situation in MRI, there are as yet no hepatospecific contrast agents available for CT. These features now permit the acquisition of similar diagnostic information to that attainable on contrast-enhanced MRI with conventional extracellular gadolinium contrast agents, where information derives from differential blood flow between the tumor and surrounding normal liver parenchyma. In particular, CT has substantially shorter acquisition times, the possibility to acquire thin sections on a routine basis within a single breath-hold, the opportunity to retrospectively calculate thinner or thicker sections from the same raw data, and improved 3D-postpro-cessing techniques. With the recent developments in MDCT technology, particularly the emergence of 16- and 64-row scanners combined with highly concentrated iodinated contrast agents, the impact of CT in both detection, and to a lesser extent, characterization of focal liver lesions has markedly improved. However, until the advent of multi-detector CT (MDCT), the value of conventional CT for the characterization of focal liver lesions was generally considered to be inferior to that of contrast-enhanced magnetic resonance imaging (MRI). Computed tomography (CT) has generally been considered the imaging approach of choice for the detection of liver masses principally because of the ease of performing and interpreting large numbers of examinations, its widespread availability, and its generally acknowledged superior ability to evaluate the ex tra-hepatic abdomen. Ultrasound (US) has traditionally been used for the primary screening of patients with abdominal pain, but the advent of contrast-enhanced US techniques now makes it a highly capable methodology for both the characterization and improved detection of liver masses. evaluation of the intra- and extrahepatic extent of tumor.Īll three of the major non-invasive imaging modalities have roles to play in liver imaging.The imaging evaluation of patients with suspected liver masses has three principal purposes: 3.1.2 Hepatocyte-Targeted Contrast Agentsģ.1.3 Agents with Combined Extracellular and Hepatocyte-Specific Distributionģ.2 Injection Schemes for Liver MRI with Different Contrast Agentsģ.3 Radiologic Classification of Focal Liver Lesions on Unenhanced and Contrast-Enhanced MRI
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