The use of FDG-positron emission tomography for the evaluation of colorectal metastases of the liver

Each year at least 130,000 people in the United States are diagnosed with c olorectal carcinoma. Approximately 14,000 of these patients will have liver metastases, and 20 per cent of these patients will die from these metastas es. Surgical resection is the only possible chance for cure in patients wit h only intrahepatic metastases, and extrahepatic disease is a contraindicat ion to glucose metabolism. Positron emission tomography (PET) allows the in vivo study of the uptake and use of glucose in human cells. Here, we revie w our experience with the use of PET imaging for the diagnosis and manageme nt of colorectal metastases of the liver. We conducted a retrospective char t review of 14 patients undergoing PET imaging for known or suspected hepat ic metastases from colorectal carcinoma. Results of CT, magnetic resonance imaging, and PET images were compared with pathological specimens. CT scan identified 7 lesions, and PET identified 31 intrahepatic lesions. Of the 6 patients who underwent surgery, CT identified 4 (20%) and PET identified 17 (85%) of the 20 intrahepatic metastases histologically confirmed. The accu racy (number of lesions) of CT and PET was 20 per cent and 85 per cent, res pectively. CT scans had a sensitivity (number of patients) of 50 per cent, and PET had a sensitivity of 100 per cent in patients undergoing surgical r esection. PET imaging altered the management in 49 per cent of patients. Tw enty-one per cent of patients had their surgery cancelled due to previously undiagnosed extrahepatic metastases. Twenty-one per cent of patients had n egative CT scans and underwent surgery on the basis of their PET images, an d all had histologically proven disease. One patient avoided a second-look laparotomy when PET revealed a lesion seen on CT to be false positive. PET is an ideal imaging modality to detect intra- and extrahepatic metastases f rom colorectal carcinomas and would aid in the surgical management of these patients.