@article {Donati692, author = {Olivio F. Donati and Thomas F. Hany and Caecilia S. Reiner and Gustav K. von Schulthess and Borut Marincek and Burkhardt Seifert and Dominik Weishaupt}, title = {Value of Retrospective Fusion of PET and MR Images in Detection of Hepatic Metastases: Comparison with 18F-FDG PET/CT and Gd-EOB-DTPA{\textendash}Enhanced MRI}, volume = {51}, number = {5}, pages = {692--699}, year = {2010}, doi = {10.2967/jnumed.109.068510}, publisher = {Society of Nuclear Medicine}, abstract = {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){\textendash}enhanced MRI, and retrospectively fused PET and MRI (PET/MRI). Methods: Thirty-seven patients (mean age {\textpm} SD, 60.2 {\textpm} 12 y) with suspected liver metastases underwent PET/CT and Gd-EOB-DTPA{\textendash}enhanced MRI within 0{\textendash}30 d (mean, 11.9 {\textpm} 9 d). PET and Gd-EOB-DTPA{\textendash}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{\textendash}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{\textendash}enhanced MRI (64\% and 85\%; P = 0.002). Sensitivity in the detection and characterization of liver metastases for PET/CT, Gd-EOB-DTPA{\textendash}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{\textendash}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{\textendash}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{\textendash}enhanced MRI, PET/MRI resulted in a nonsignificant increase in sensitivity and diagnostic confidence.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/51/5/692}, eprint = {https://jnm.snmjournals.org/content/51/5/692.full.pdf}, journal = {Journal of Nuclear Medicine} }