title: Current image acquisition options in PET/MR.
abstract: Whole-body PET/MR hybrid imaging combines excellent soft tissue contrast and various functional imaging parameters provided by MR with high sensitivity and quantification of radiotracer uptake provided by PET. Although clinical evaluation now is under way, PET/MR demands for new technologies and innovative solutions, currently subject to interdisciplinary research. Attenuation correction (AC) of human soft tissues and of hardware components has to be MR based to maintain quantification of PET imaging as CT attenuation information is missing. MR-based AC is inherently associated with the following challenges: patient tissues are segmented into only few tissue classes, providing discrete attenuation coefficients; bone is substituted as soft tissue in MR-based AC; the limited field of view in MRI leads to truncations in body imaging and, consequently, in MR-based AC; and correct segmentation of lung tissue may be hampered by breathing artifacts. Use of time of flight during PET image acquisition and reconstruction, however, may improve the accuracy of AC. This article provides a status of current image acquisition options in PET/MR hybrid imaging.
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Ronald
authors.initials: R
authors.lastname: Boellaard
authors.affiliation: Erwin L. Hahn Institute for MR Imaging, University of Duisburg-Essen, Essen, Germany; High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany. Electronic address: Harald.quick@uni-due.de.
authors.forename: Harald H
authors.initials: HH
authors.lastname: Quick
mesh_terms: D016477:Artifacts; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D049268:Positron-Emission Tomography / Q000295:instrumentation / Q000379:methods*