Murine pulmonary imaging at 7T: T2* and T 1 with anisotropic UTE

Magn Reson Med. 2018 Apr;79(4):2254-2264. doi: 10.1002/mrm.26872. Epub 2017 Aug 15.

Abstract

Purpose: To measure the T2* and T1 of mouse lung at 7T via anisotropic-resolution radial ultrashort echo-time imaging with ellipsoidal k-space coverage.

Methods: Ellipsoidal field-of-view was created by expanding uniform spherical k-space coverage. The effects of T2* and ellipsoidal sampling on image resolution were investigated by using point-spread-function analysis and resolution phantoms. Finally, this ellipsoidal sampling approach was used to measure the lung T2* and T1 of healthy C57BL/6 mice at the increasingly common preclinical field strength of 7T.

Results: Lung parenchyma T2* of 17- to 23-week-old mice at 7T was 0.395 ± 0.033 ms. T1 of lung and left- and right-heart ventricles was 1452.5 ± 87.0 ms, 1810.5 ± 54.6 ms, and 1602.6 ± 120.9 ms, respectively. Ellipsoidal k-space sampling provides enhanced resolution for a fixed scanning time or provides equivalent (although anisotropic) spatial resolution with reduced scanning times, while simultaneously avoiding fold-in artifacts.

Conclusion: Using these techniques, the first T2* and T1 measures of mouse lung at 7T are reported. Ultrashort echo-time imaging with ellipsoidal k-space coverage significantly increases in-plane resolution without increasing scanning time, or equivalently, decreases scanning time while maintaining equivalent in-plane resolution. Magn Reson Med 79:2254-2264, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Keywords: T2*; T1; ellipsoidal k-space coverage; murine lung; UTE MRI.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Animals
  • Anisotropy
  • Artifacts
  • Heart / diagnostic imaging
  • Image Interpretation, Computer-Assisted / methods*
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional
  • Lung / diagnostic imaging*
  • Magnetic Resonance Imaging*
  • Mice
  • Mice, Inbred C57BL
  • Models, Statistical
  • Phantoms, Imaging