The liver is one of the most common organs to be involved with metastatic diseases, which arises most frequently from primary sites in the colon, breast, lung, pancreas, and stomach [1]. The accurate detection of metastatic disease at the time of diagnosis or during the course of treatment remains crucial to patient management. Early identification provides to opportunity for resection, which, at least in cases of colorectal carcinoma, has been shown to prolong survival [2]. Imaging-guided interstitial therapies, including cryoablation, laser photo-coagulation, radio frequency and microwave ablation, and percutaneous ethanol injection, are evolving and may play both a curative and a palliative role, but their success depends on accurate imaging of liver neoplasms.
Both CT and MR imaging have benefited from rapid technologic advances and MR imaging, in particular, from the advent of new contrast agents. Comparative studies must be carefully scrutinized. Studies may quickly become outdated as new methods are introduced. An ideal examination provides high sensitivity and specificity and is noninvasive, low in cost, and widely available. No single study currently fits that profile. Studies available include helical CT using uni-, bi-, and triphasic techniques, CT during arterial portography, and MR imaging either unenhanced or enhanced with extracellular or tissue-specific contrast agents.
Factors such as availability, technical and clinical expertise, cost, and patient tolerance affect the decision of study choice. Familiarity with the technique used is important because false-positive diagnoses can have a substantial effect on patient management. The choice of imaging study should be influenced by the clinical indications. Objectives of oncologic liver imaging include screening for the presence of disease, the characterization of liver lesions, anatomic localization, evaluation of interval change during a course of treatment, and assessment of vascular patency. When the study is tailored to the clinical objectives, imaging resources are used optimally. This review will discuss imaging options and their appropriate indications.