Evaluation of the Liver for Metastatic Disease

Erik K. Paulson, MD1, 1Department of Radiology, Duke University Medical Center, Durham, North Carolina.

Semin Liver Dis. 2001;21(2) 

In This Article

Detection By Imaging

Detection of metastatic disease by imaging is based on lesion size, lesion-to-liver contrast difference, and lesion-to-liver edge definition.[1,16] To maximize the detection of lesions, it is critical to perform imaging techniques with high spatial resolution. High-spatial resolution imaging can be maximized with thin collimation computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound (US). Thin collimation imaging also results in improved lesion-to-liver edge definition because partial volume artifacts will be reduced.

Because the composition of metastatic deposits differs from the background liver (metastases usually contain more water), they may be detected on CT on MRI studies performed without the administration of contrast material. However, the lesion-to-liver contrast difference will be maximized by selectively enhancing the background liver parenchyma by the administration of contrast material. With CT and MRI, the most common approach to enhance the parenchyma is to inject iodine-containing contrast or gadolinium-containing contrast material, respectively.

There are several methods available to screen the liver for metastatic disease. Choice of modality will be based on clinical scenario and institutional preference. Table 1 lists the sensitivity of a variety of cross-sectional imaging techniques for the detection of individual metastases. Know that lesions less than 1 cm in size are difficult to detect by any modality.[1] Furthermore, be aware that the detection of each and every lesion -- critical to the liver surgeon -- is far more difficult than detecting patients with metastatic disease, in whom lesion-by-lesion analysis may be less critical.

Hundreds of articles have been written regarding metastatic detection using cross-sectional imaging techniques. Rather than attempt to provide an exhaustive review of the efficacy of each imaging technique, fundamental advantages and disadvantages of each technique will be discussed.