Optimizing the detection of colorectal liver metastases within the Canadian health care system

Colorectal metastases in the liver are common. In appropriately selected patients resection can increase the 5-year survival rate from 0% to 33%. When consulted by their surgery colleagues about patient selection, radiologists now have a wide choice of imaging methods, including nuclear medicine, ultrasonography, unenhanced computed tomography (CT), intravenously enhanced CT (by infusion or by the dynamic and delayed methods), arterially enhanced CT (specifically, CT arterial portography and CT angiography) and magnetic resonance imaging. In Canada this wide range of techniques has appeared in an era of cost constraint. This article discusses the surgical background for imaging colorectal metastases in the liver and reviews the available imaging methods. The authors present an algorithmic approach that attempts to balance the need for accuracy with the logistic and financial constraints under which radiologists work in Canada. They suggest that this algorithm would allow optimal use of available resources in most Canadian hospitals.