title: Fast T1 and T2 mapping methods: the zoomed U-FLARE sequence compared with EPI and snapshot-FLASH for abdominal imaging at 11.7 Tesla.
abstract: OBJECTIVE
  A newly adapted zoomed ultrafast low-angle RARE (U-FLARE) sequence is described for abdominal imaging applications at 11.7 Tesla and compared with the standard echo-plannar imaging (EPI) and snapshot fast low angle shot (FLASH) methods.
  
  
  METHODS
  Ultrafast EPI and snapshot-FLASH protocols were evaluated to determine relaxation times in phantoms and in the mouse kidney in vivo. Owing to their apparent shortcomings, imaging artefacts, signal-to-noise ratio (SNR), and variability in the determination of relaxation times, these methods are compared with the newly implemented zoomed U-FLARE sequence.
  
  
  RESULTS
  Snapshot-FLASH has a lower SNR when compared with the zoomed U-FLARE sequence and EPI. The variability in the measurement of relaxation times is higher in the Look-Locker sequences than in inversion recovery experiments. Respectively, the average T1 and T2 values at 11.7 Tesla are as follows: kidney cortex, 1810 and 29 ms; kidney medulla, 2100 and 25 ms; subcutaneous tumour, 2365 and 28 ms.
  
  
  CONCLUSIONS
  This study demonstrates that the zoomed U-FLARE sequence yields single-shot single-slice images with good anatomical resolution and high SNR at 11.7 Tesla. Thus, it offers a viable alternative to standard protocols for mapping very fast parameters, such as T1 and T2, or dynamic processes in vivo at high field.
authors.affiliation: Molecular Imaging Unit, CIC biomaGUNE, Paseo Miramón 182, 20009, Donostia-San Sebastián, Spain. gpastor@cicbiomagune.es.
authors.forename: Géraldine
authors.identifier: http://orcid.org/0000-0001-5211-9132
authors.initials: G
authors.lastname: Pastor
authors.affiliation: Molecular Imaging Unit, CIC biomaGUNE, Paseo Miramón 182, 20009, Donostia-San Sebastián, Spain.|Metabolism Division, Johns Hopkins University, CMSC Building 10-113, Baltimore, MD, 21287, USA.
authors.forename: María
authors.initials: M
authors.lastname: Jiménez-González
authors.affiliation: Molecular Imaging Unit, CIC biomaGUNE, Paseo Miramón 182, 20009, Donostia-San Sebastián, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Plaza-García
authors.affiliation: Molecular Imaging Unit, CIC biomaGUNE, Paseo Miramón 182, 20009, Donostia-San Sebastián, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Beraza
authors.affiliation: Molecular Imaging Unit, CIC biomaGUNE, Paseo Miramón 182, 20009, Donostia-San Sebastián, Spain.
authors.forename: Torsten
authors.initials: T
authors.lastname: Reese
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging* / Q000473:pathology; D000818:Animals; D045744:Cell Line, Tumor; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007668:Kidney / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging* / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: Abdomen; High-field; Magnetic resonance imaging; Mice; Relaxation