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

Computed Tomography

In our practice, contrast-enhanced CT is the mainstay for detecting patients with metastatic disease. Advantages of CT include reasonable capital equipment cost, wide availability, exam-to-exam reproducibility, and extremely short acquisition times.[1] Importantly, CT scans are well accepted by referring surgeons and oncologists. Disadvantages of CT include the use of intravenous contrast material (cost, allergic reactions, nephrotoxicity) and ionizing radiation. With spiral CT scanners, including multidetector scanners, it is now possible to acquire two or even three acquisitions through the liver during a single intravenous (IV) bolus of contrast.[39,40] This allows imaging to be performed during the so-called hepatic arterial dominant phase of enhancement, which has been shown to be sensitive for detecting hypervascular tumors and allows characterization of both benign and malignant tumors.[41,42,43,44] Although there is a temptation to perform multiple acquisitions during an injection of contrast, each acquisition is associated with increasing radiation and cost. Furthermore, CT is an excellent method to detect extrahepatic disease.

Invasive catheter-assisted CT has been shown to be extremely sensitive for detecting metastatic disease and for many years was routine in patients anticipating liver resection.[45,46,47,48,49] However, in most institutions invasive catheter-assisted CT (CT angiography or CT arterial portography) has been replaced by well-performed spiral CT using a simple intravenous injection[50] and MRI following IV administration of a liver-specific contrast agent. The main drawback of invasive CT techniques is the requirement for selective placement of a catheter into the hepatic or splenic artery. In addition, the images are often degraded by perfusion defects and areas of hyperenhancement that could easily be mistaken for lesions.[51,52]

With spiral CT scanners it is now possible to address the imaging issues relevant to liver surgery with a straightforward intravenous injection of contrast that usually obviates the need for catheter-assisted CT. With a single contrast bolus, one may acquire CT images suitable for reconstruction into an excellent-quality CT angiogram, followed by a diagnostic acquisition of the liver to detect and characterize metastatic deposits.[53,54,55,56,57] The CT angiograms are of sufficient quality to delineate variants of hepatic anatomy, which can aid the liver surgeon in planning resection and placement of hepatic artery pumps for selective perfusion of chemotherapeutic agents (Fig. 1). The diagnostic scans are sufficiently sensitive for the detection of metastatic disease.[58]

Figure 1

CT angiogram prior to liver resection. A. CT angiogram delineates the anatomy of the branches of the celiac axis. The common hepatic artery, left gastric artery, and splenic artery are labeled as CHA, LGH, and SA, respectively. The right (R) and left hepatic (L) artery show conventional anatomy.