Intracranial time-of-flight MR angiography at 7T with comparison to 3T

J Magn Reson Imaging. 2007 Oct;26(4):900-4. doi: 10.1002/jmri.21097.


Purpose: To establish the feasibility of intracranial time-of-flight (TOF) MR angiography (MRA) at 7T using phased array coils and to compare its performance to 3T.

Materials and methods: In an initial study, five normal volunteers were scanned at 7T and 3T using eight-channel coils and standard acquisition parameters from a clinical TOF protocol. In a second study three additional studies were performed at 7T and 3T using empirically optimized 7T parameters. Contrast-to-noise (CNR) values were measured for major vessel segments.

Results: All measurements documented CNR increases at 7T, with a mean increase of 83% in the initial study and 88% in the second study. The CNR values achieved using the latter protocol were similar to the values obtained in the initial study, despite the 42% reduction expected due to the higher spatial resolution. CNR in the smaller peripheral vessels was increased dramatically, resulting in excellent visualization at high resolution.

Conclusion: TOF MRA at 7T demonstrated improved visualization of the intracranial vasculature, particularly the smaller peripheral vessels, and may benefit studies of small aneurysms, atherosclerosis, vasospasm, and vasculitis.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Brain / anatomy & histology*
  • Brain / pathology
  • Contrast Media
  • Humans
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional
  • Intracranial Aneurysm / diagnosis
  • Intracranial Aneurysm / pathology
  • Magnetic Resonance Angiography / instrumentation*
  • Magnetic Resonance Angiography / methods*
  • Reproducibility of Results
  • Time Factors


  • Contrast Media