title: Lung imaging under free-breathing conditions.
abstract: Respiratory motion and pulsatile blood flow can generate artifacts in morphological and functional lung imaging. Total acquisition time, and thus the achievable signal to noise ratio, is limited when performing breath-hold and/or electrocardiogram-triggered imaging. To overcome these limitations, imaging during free respiration can be performed using respiratory gating/triggering devices or navigator echoes. However, these techniques provide only poor gating resolution and can induce saturation bands and signal fluctuations into the lung volume. In this work, acquisition schemes for nonphase encoded navigator echoes were implemented into different sequences for morphological and functional lung imaging at 1.5 Tesla (T) and 0.2T. The navigator echoes allow monitoring of respiratory motion and provide an ECG-trigger signal for correction of the heart cycle without influencing the imaged slices. Artifact free images acquired during free respiration using a 3D GE, 2D multislice TSE or multi-Gradient Echo sequence for oxygen-enhanced T(2)(*) quantification are presented.
authors.affiliation: Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany. oechsner@physik.uni-wuerzburg.de
authors.forename: Markus
authors.initials: M
authors.lastname: Oechsner
authors.forename: Eberhard D
authors.initials: ED
authors.lastname: Pracht
authors.forename: Daniel
authors.initials: D
authors.lastname: Staeb
authors.forename: Johannes F T
authors.initials: JF
authors.lastname: Arnold
authors.forename: Herbert
authors.initials: H
authors.lastname: Köstler
authors.forename: Dietbert
authors.initials: D
authors.lastname: Hahn
authors.forename: Meinrad
authors.initials: M
authors.lastname: Beer
authors.forename: Peter M
authors.initials: PM
authors.lastname: Jakob
mesh_terms: D000465:Algorithms; D016477:Artifacts; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008168:Lung / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009038:Motion; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity