title: Cardiac-respiratory self-gated cine ultra-short echo time (UTE) cardiovascular magnetic resonance for assessment of functional cardiac parameters at high magnetic fields.
abstract: BACKGROUND
  To overcome flow and electrocardiogram-trigger artifacts in cardiovascular magnetic resonance (CMR), we have implemented a cardiac and respiratory self-gated cine ultra-short echo time (UTE) sequence. We have assessed its performance in healthy mice by comparing the results with those obtained with a self-gated cine fast low angle shot (FLASH) sequence and with echocardiography.
  
  
  METHODS
  2D self-gated cine UTE (TE/TR = 314 μs/6.2 ms, resolution: 129 × 129 μm, scan time per slice: 5 min 5 sec) and self-gated cine FLASH (TE/TR = 3 ms/6.2 ms, resolution: 129 × 129 μm, scan time per slice: 4 min 49 sec) images were acquired at 9.4 T. Volume of the left and right ventricular (LV, RV) myocardium as well as the end-diastolic and -systolic volume was segmented manually in MR images and myocardial mass, stroke volume (SV), ejection fraction (EF) and cardiac output (CO) were determined. Statistical differences were analyzed by using Student t test and Bland-Altman analyses.
  
  
  RESULTS
  Self-gated cine UTE provided high quality images with high contrast-to-noise ratio (CNR) also for the RV myocardium (CNRblood-myocardium = 25.5 ± 7.8). Compared to cine FLASH, susceptibility, motion, and flow artifacts were considerably reduced due to the short TE of 314 μs. The aortic valve was clearly discernible over the entire cardiac cycle. Myocardial mass, SV, EF and CO determined by self-gated UTE were identical to the values measured with self-gated FLASH and showed good agreement to the results obtained by echocardiography.
  
  
  CONCLUSIONS
  Self-gated UTE allows for robust measurement of cardiac parameters of diagnostic interest. Image quality is superior to self-gated FLASH, rendering the method a powerful alternative for the assessment of cardiac function at high magnetic fields.
authors.forename: Verena
authors.initials: V
authors.lastname: Hoerr
authors.forename: Nina
authors.initials: N
authors.lastname: Nagelmann
authors.forename: Arno
authors.initials: A
authors.lastname: Nauerth
authors.forename: Michael T
authors.initials: MT
authors.lastname: Kuhlmann
authors.forename: Jörg
authors.initials: J
authors.lastname: Stypmann
authors.forename: Cornelius
authors.initials: C
authors.lastname: Faber
mesh_terms: D000818:Animals; D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques; D015150:Echocardiography, Doppler; D005260:Female; D006339:Heart Rate; D007090:Image Interpretation, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D056152:Respiratory Rate; D059629:Signal-To-Noise Ratio; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right