TY - JOUR T1 - Value of Retrospective Fusion of PET and MR Images in Detection of Hepatic Metastases: Comparison with <sup>18</sup>F-FDG PET/CT and Gd-EOB-DTPA–Enhanced MRI JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 692 LP - 699 DO - 10.2967/jnumed.109.068510 VL - 51 IS - 5 AU - Olivio F. Donati AU - Thomas F. Hany AU - Caecilia S. Reiner AU - Gustav K. von Schulthess AU - Borut Marincek AU - Burkhardt Seifert AU - Dominik Weishaupt Y1 - 2010/05/01 UR - http://jnm.snmjournals.org/content/51/5/692.abstract N2 - The purpose of this study was to compare the accuracy of lesion detection and diagnostic confidence between 18F-FDG PET/CT, gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)–enhanced MRI, and retrospectively fused PET and MRI (PET/MRI). Methods: Thirty-seven patients (mean age ± SD, 60.2 ± 12 y) with suspected liver metastases underwent PET/CT and Gd-EOB-DTPA–enhanced MRI within 0–30 d (mean, 11.9 ± 9 d). PET and Gd-EOB-DTPA–enhanced MR image data were retrospectively fused. Images were reviewed independently by 2 readers who identified and characterized liver lesions using PET/CT, Gd-EOB-DTPA–enhanced MRI, and PET/MRI. Each liver lesion was graded on a 5-point confidence scale ranging from definitely benign (grade of 1) to definitely malignant (grade of 5). The accuracy of each technique was determined by receiver-operating-characteristic analysis. Histopathology served as the standard of reference for all patients with malignant lesions. Results: A total of 85 liver lesions (55 liver metastases [65%] and 30 benign lesions [35%]) were present in 29 (78%) of the 37 patients. Twenty-four (65%) of the 37 patients had liver metastases. The detection rate of liver lesions was significantly lower for PET/CT than for Gd-EOB-DTPA–enhanced MRI (64% and 85%; P = 0.002). Sensitivity in the detection and characterization of liver metastases for PET/CT, Gd-EOB-DTPA–enhanced MRI, PET/MRI in reader 1, and PET/MRI in reader 2 was 76%, 91%, 93%, and 93%, respectively; the respective specificity values were 90%, 100%, 87%, and 97%. The difference in sensitivity between PET/CT and PET/MRI was significant (P = 0.023). The level of confidence regarding liver lesions larger than 1 cm in diameter was significantly higher in PET/MRI than in PET/CT (P = 0.046). Accuracy values (area under the receiver-operating-characteristic curve) for PET/CT, Gd-EOB-DTPA–enhanced MRI, PET/MRI in reader 1, and PET/MRI in reader 2 were 0.85, 0.94, 0.92, and 0.96, respectively. Conclusion: The sensitivity of Gd-EOB-DTPA–enhanced MRI and PET/MRI in the detection of liver metastases is higher than that of PET/CT. Diagnostic confidence was significantly better with PET/MRI than with PET/CT regarding lesions larger than 1 cm in diameter. Compared with Gd-EOB-DTPA–enhanced MRI, PET/MRI resulted in a nonsignificant increase in sensitivity and diagnostic confidence. ER -