Jarmo Teuho1, Jarkko Johansson2, Jani Linden2, Adam Espe Hansen3, Søren Holm3, Sune H Keller3, Gaspar Delso4, Patrick Veit-Haibach4, Keiichi Magota5, Virva Saunavaara2, Tuula Tolvanen2, Mika Teräs6, Hidehiro Iida7. 1. Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland jarmo.teuho@tyks.fi. 2. Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland. 3. Department of Clinical Physiology, Nuclear Medicine, and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. 4. PET/CT-MR Center, University Hospital Zurich, Zurich, Switzerland. 5. Section of Nuclear Medicine, Department of Radiology, Hokkaido University Hospital, Sapporo, Japan. 6. Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland Department of Medical Physics, Turku University Hospital, Turku, Finland; and. 7. National Cerebral and Cardiovascular Center, Osaka, Japan.
Abstract
UNLABELLED: A spatial bias in brain PET/MR exists compared with PET/CT, because of MR-based attenuation correction. We performed an evaluation among 4 institutions, 3 PET/MR systems, and 4 PET/CT systems using an anthropomorphic brain phantom, hypothesizing that the spatial bias would be minimized with CT-based attenuation correction (CTAC). METHODS: The evaluation protocol was similar to the quantification of changes in neurologic PET studies. Regional analysis was conducted on 8 anatomic volumes of interest (VOIs) in gray matter on count-normalized, resolution-matched, coregistered data. On PET/MR systems, CTAC was applied as the reference method for attenuation correction. RESULTS: With CTAC, visual and quantitative differences between PET/MR and PET/CT systems were minimized. Intersystem variation between institutions was +3.42% to -3.29% in all VOIs for PET/CT and +2.15% to -4.50% in all VOIs for PET/MR. PET/MR systems differed by +2.34% to -2.21%, +2.04% to -2.08%, and -1.77% to -5.37% when compared with a PET/CT system at each institution, and these differences were not significant (P ≥ 0.05). CONCLUSION: Visual and quantitative differences between PET/MR and PET/CT systems can be minimized by an accurate and standardized method of attenuation correction. If a method similar to CTAC can be implemented for brain PET/MRI, there is no reason why PET/MR should not perform as well as PET/CT.
UNLABELLED: A spatial bias in brain PET/MR exists compared with PET/CT, because of MR-based attenuation correction. We performed an evaluation among 4 institutions, 3 PET/MR systems, and 4 PET/CT systems using an anthropomorphic brain phantom, hypothesizing that the spatial bias would be minimized with CT-based attenuation correction (CTAC). METHODS: The evaluation protocol was similar to the quantification of changes in neurologic PET studies. Regional analysis was conducted on 8 anatomic volumes of interest (VOIs) in gray matter on count-normalized, resolution-matched, coregistered data. On PET/MR systems, CTAC was applied as the reference method for attenuation correction. RESULTS: With CTAC, visual and quantitative differences between PET/MR and PET/CT systems were minimized. Intersystem variation between institutions was +3.42% to -3.29% in all VOIs for PET/CT and +2.15% to -4.50% in all VOIs for PET/MR. PET/MR systems differed by +2.34% to -2.21%, +2.04% to -2.08%, and -1.77% to -5.37% when compared with a PET/CT system at each institution, and these differences were not significant (P ≥ 0.05). CONCLUSION: Visual and quantitative differences between PET/MR and PET/CT systems can be minimized by an accurate and standardized method of attenuation correction. If a method similar to CTAC can be implemented for brain PET/MRI, there is no reason why PET/MR should not perform as well as PET/CT.
Authors: Yi Su; Andrei G Vlassenko; Lars E Couture; Tammie Ls Benzinger; Abraham Z Snyder; Colin P Derdeyn; Marcus E Raichle Journal: J Cereb Blood Flow Metab Date: 2016-01-01 Impact factor: 6.200