title: Motion correction in MR thermometry of abdominal organs: a comparison of the referenceless vs. the multibaseline approach.
abstract: Reliable temperature and thermal-dose measurements using proton resonance frequency shift-based magnetic resonance (MR) thermometry for MR-guided ablation of abdominal organs require a robust correction of artefacts induced by the target displacement through an inhomogeneous and time-variant magnetic field. Two correction approaches emerged recently as promising candidates to allow continuous real-time MR-thermometry under free-breathing conditions: The multibaseline correction method, which relies on a pre-recorded correction table allowing to correct for periodic phase changes, and the referenceless method, which depends on a background phase estimation in the target area based on the assumption of a smooth spatial variation of the phase across the organ. This study combines both methods with real-time in-plane motion correction to permit both temperature and thermal-dose calculations on the fly. Subsequently, the practical aspects of both methods are compared in two application scenarios, a radio frequency-ablation and a high-intensity focused ultrasound ablation. A hybrid approach is presented that exploits the strong points of both methods, allowing accurate and precise proton resonance frequency-thermometry measurements during periodical displacement, even in the presence of spontaneous motion and strong susceptibility variations in the target area.
authors.affiliation: Laboratory for Molecular and Functional Imaging: From Physiology to Therapy, UMR 5231 CNRS/Université Bordeaux 2, 146 rue Léo Saignat, F-33076 Bordeaux, France.
authors.forename: Baudouin Denis
authors.initials: BD
authors.lastname: de Senneville
authors.forename: Sébastien
authors.initials: S
authors.lastname: Roujol
authors.forename: Chrit
authors.initials: C
authors.lastname: Moonen
authors.forename: Mario
authors.initials: M
authors.lastname: Ries
mesh_terms: D000465:Algorithms; D000818:Animals; D016477:Artifacts; D001831:Body Temperature / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods* / Q000592:standards; D007090:Image Interpretation, Computer-Assisted / Q000379:methods* / Q000592:standards; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D009068:Movement; D019047:Phantoms, Imaging; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D013817:Thermography / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D014781:Viscera / Q000502:physiology*