RT Journal Article SR Electronic T1 Diagnostic utility of rapid MR images potentially useful for attenuation correction (AC) and anatomic registration (AR) compared to low dose CT, direct comparison in a PET/CT-MR system JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 493 OP 493 VO 52 IS supplement 1 A1 Caecilia Mader A1 Philippe Appenzeller A1 David Crook A1 Felix Kuhn A1 Daniel Nanz A1 Thomas Hany A1 Juerg Hodler A1 Gustav vonSchulthess A1 Daniel Schmid YR 2011 UL http://jnm.snmjournals.org/content/52/supplement_1/493.abstract AB 493 Objectives To investigate the diagnostic utility of mapping PET-positive findings to rapid 3T-MR-images using an axial T1w fast gradient echo sequence, to be used potentially for PET AC and AR. Methods In a PET/CT-MR system integrated by a shuttle, 23 patients (mean age 63 years) were transferred to 3T MR (GE Healthcare 750) after routine PET/CT (GE-690-TOF), while maintaining the patient immobilized on a transfer board. MR-images were obtained using a body-coil and LAVA-flex-water sequence (total acquisition time 128-144 sec). The PET-MR and PET/CT data sets were analysed using commercially available fusion software (AW4.5) by two radiologists/nuclear physicians in consensus. A total of 108 PET-positive lesions were identified/characterized (mean diameter 18mm, 6-99mm). A 3-point-scale was used to evaluate lesion conspicuity and image quality of CT and MR images. Results Lesion characterization was successful in 78/108(72%) at CT and MR, in 19/108(18%) at CT only, in 5/108(5%) at MR only and was not possible with either in 6/108(6%). Localization was successful for CT and MR in 88/108(82%), for CT alone in 14/108(13%) and was not possible with either in 2/108(2%). Lesion conspicuity and image quality in low-dose CT was superior to MRI (p=0.011 and p<0.001, respectively). Conclusions Rapidly acquired axial T1w fast dual gradient echo MR images using a body coil are inferior in lesion identification, localization and image quality compared to low dose CT. However, some MR-findings were not visible at CT, suggesting the potential utility of an integrated PET-MR system. Surface coil-configuration(s) will be necessary to improve MR image quality