We routinely obtain contrast-enhanced multidetector helical computed tomography (CT) imaging of the chest, abdomen and pelvis on patients being evaluated for hepatic resection. Although somewhat controversial, we obtain chest CT scans to rule out pulmonary metastasis because of its high degree of sensitivity (37) and potential to change management. However, a potential weakness of routinely obtaining chest CT scans is its lack of specificity and false positive rate of identifying non-specific

small pulmonary Inhibitors,research,lifescience,medical nodules. These small pulmonary nodules are frequently under the resolution for PET scans, may be nearly impossible to biopsy percutaneously, and probably do not justify a thoracotomy or thoracoscopic procedure. Forty-three percent of patients selected for liver resection for colorectal metastases at our institution have subcentimeter pulmonary nodules of which one third ultimately proved to be metastatic signaling pathway disease (38). However, the presence of limited subcentimeter Inhibitors,research,lifescience,medical pulmonary nodules did not significantly impact 3-year Inhibitors,research,lifescience,medical DSS and should not necessarily preclude liver resection (38). The goal of hepatic imaging is to define the number, location,

distribution and relation of the hepatic tumors to vascular and biliary structures. The standard CT scan to evaluate for liver metastasis is a triphasic scan with 2.5-5

mm slices. The arterial phase is useful to define arterial anatomy and identify co-existing benign lesions. However, colorectal metastases are not very vascular and therefore Inhibitors,research,lifescience,medical are best seen on the portal venous phase where they appear hypodense. The sensitivity of identifying liver metastasis with contrast enhanced multidetector Inhibitors,research,lifescience,medical CT scans approaches 80-90% (39-41). Superior image resolution of CT provides excellent vascular and anatomic detail which is useful in preoperative planning. However, CT lacks the sensitivity and ability to characterize lesions less than 1cm. Contrast enhanced magnetic resonance imaging (MRI) is another useful imaging modality for assessing the extent of liver disease with an accuracy of 80-90% (42-44). ADP ribosylation factor MRI is most useful for evaluating equivocal lesions and differentiating metastasis from benign lesions. It may also be beneficial in defining relationships to the biliary tree with MRI cholangiopancreatography. We selectively use contrast enhanced MRI in order to characterize indeterminate liver lesions and for patients with steatosis from obesity, diabetes and previous chemotherapy. MRI is particularly useful in identifying ‘disappearing’ tumors while on chemotherapy since many of these tumors are not visible due to the development of hepatic steatosis (45).