818.Full-Text.Pdf
Effect of Attenuation Correction on Regional Quantification Between PET/MR and PET/CT: A Multicenter Study Using a 3-Dimensional Brain Phantom Jarmo Teuho1, Jarkko Johansson1, Jani Linden1, Adam Espe Hansen2, Søren Holm2, Sune H. Keller2, Gaspar Delso3, Patrick Veit-Haibach3, Keiichi Magota4, Virva Saunavaara1, Tuula Tolvanen1, Mika Teräs1,5, and Hidehiro Iida6 1Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland; 2Department of Clinical Physiology, Nuclear Medicine, and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; 3PET/CT-MR Center, University Hospital Zurich, Zurich, Switzerland; 4Section of Nuclear Medicine, Department of Radiology, Hokkaido University Hospital, Sapporo, Japan; 5Department of Medical Physics, Turku University Hospital, Turku, Finland; and 6National Cerebral and Cardiovascular Center, Osaka, Japan However, quantitative accuracy remains inconsistent between A spatial bias in brain PET/MR exists compared with PET/CT, PET/MR and PET/CT systems, with MR-based attenuation cor- because of MR-based attenuation correction. We performed an rection (MRAC) suspected of being the main source of bias (3–5). evaluation among 4 institutions, 3 PET/MR systems, and 4 PET/CT MRAC remains a challenge, as MR images do not correspond to systems using an anthropomorphic brain phantom, hypothesizing electron density and cannot be directly translated to m-values that the spatial bias would be minimized with CT-based attenuation (6,7). Currently, conversion to m-values is performed via image correction (CTAC). Methods: The evaluation protocol was similar to segmentation (6–8). the quantification of changes in neurologic PET studies. Regional Although MRAC is feasible for whole-body imaging, large and analysis was conducted on 8 anatomic volumes of interest (VOIs) in gray matter on count-normalized, resolution-matched, coregistered spatially varying biases exist in brain PET/MR because of exclu- data.
[Show full text]