title: Long-term stability of cardiac function in normal and chronically failing mouse hearts in a vertical-bore MR system.
abstract: We previously demonstrated stability of ventricular volumes and cardiac function in normal and in chronically failing mouse hearts in MR systems with a vertical-bore magnet for up to 1 h. However, in order to exploit the benefits of an increased magnetic field strength of these MR systems in more time-consuming studies required by, for example MR spectroscopy, we investigated whether cardiac function and ventricular volumes of healthy and infarcted mice would be affected in vertical position over a prolonged period. We applied high-resolution MR cine imaging on an 11.7 T vertical MR system to monitor cardiac functional parameters of normal and chronically failing mouse hearts over a period of 3 h in an upright position, with a temporal resolution of < or =15 min. We monitored left-ventricular volumes and cardiac functional parameters in both groups. In normal mice, we detected a decrease of left-ventricular end-systolic volumes by 8 microl and an approximately 23% increase of ejection fraction over time indicating a small but detectable degree of orthostatic dysregulation. Observed changes were more pronounced in mice with heart failure. Despite significant changes in left-ventricular volumes and function, absolute values measured for all functional cardiac parameters are consistent with near-physiological conditions. Thus, mice can be studied in high-field MR systems positioned vertically for 3 h.
authors.affiliation: Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK. jurgen.schneider@cardiov.ox.ac.uk
authors.forename: Jürgen E
authors.initials: JE
authors.lastname: Schneider
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Hulbert
authors.forename: Craig A
authors.initials: CA
authors.lastname: Lygate
authors.forename: Michiel
authors.initials: M
authors.lastname: Ten Hove
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Cassidy
authors.forename: Kieran
authors.initials: K
authors.lastname: Clarke
authors.forename: Stefan
authors.initials: S
authors.lastname: Neubauer
mesh_terms: D000818:Animals; D002908:Chronic Disease; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*