Diagnostic Value Of ¹⁸F-FDG PET/CT And SUVmax For Liver Metastases From Colorectal Cancer

Objective:To investigate the diagnostic performance of ¹⁸F-fluorodeoxyglucose(¹⁸F-FDG)positron emission tomography/computed tomography（PET/CT）for detection of colorectal liver metastasis（CRLM）compared with contrast-enhanced computed tomography（ceCT）and magnetic resonance imaging（MRI）.And to study the diagnostic value of the maximum standardized uptake value（SUVmax）in CRLM.Additionally,we investigated the correlation between the SUVmax of metastatic liver lesions from colorectal cancer（CRC）and clinical characteristics of patients and tumor markers carcinoembryonic antigen（CEA）and carbohydrate antigen 199（CA199）.Methods:This study included 60 patients with confirmed CRC who were highly suspected of liver metastases.All patients underwent ¹⁸F-FDG PET/CT,ceCT,and MRI examination.The levels of CEA and CA199 were measured within one week before or after ¹⁸F-FDG PET/CT examination.The final diagnosis was confirmed by histopathological findings or clinical follow-up.Results:For the diagnostic performance of CRLM,¹⁸F-FDG PET/CT was better than that of MRI and ceCT.¹⁸F-FDG PET/CT had a sensitivity of 96.4%,accuracy of 96.7%,and negative predictive value（NPV）of 66.7%for detecting CRLM,which were better than those of MRI（92.9%,93.3%and 50.0%,respectively）.The sensitivity,specificity,accuracy and positive and negative predictive value（PPV and NPV）of ceCT in detection of CRLM were 89.3%,50.0%,86.7%,96.2%and 25.0%,respectively.The Kappa value between ¹⁸F-FDG PET/CT and final diagnosis was 0.783,which was superior to MRI and ceCT（Kappa values were0.634 and 0.268,respectively）.The liver SUVmax was significant correlated with CEA（P<0.05）,whereas there was no correlation between liver SUVmax and sex,age,location of primary tumors,pathological type,histological differentiation,and serum CA199（P>0.05）.When the cut-off value of SUVmax of liver metastatic lesions was 2.0,the sensitivity was82.1%and the specificity was 75.0%for detecting CRLM.Conclusion:The diagnostic performance of ¹⁸F-FDG PET/CT for CRLM is superior to MRI and ceCT.Liver SUVmax and serum CEA have certain value for the diagnosis of CRLM and can be used to guide clinical practice.