Comparison of echo-planar sequences for perfusion-weighted MRI: which is best?

Neuroradiology. 1998 Apr;40(4):216-21. doi: 10.1007/s002340050570.

Abstract

We compared gradient-echo (GRE), spin-echo (SE) and stimulated-echo (STE) echo-planar imaging sequences for perfusion-weighted imaging at different field strengths. Focal cerebral ischaemia was induced by endovascular occlusion of the middle cerebral artery in eight rats. MR was performed at 4.7 T or 2.35 T. With each sequence, we acquired data sets before, during and after bolus injection of Gd-DTPA with a time resolution of 1.2 s per image. The perfusion-weighted images were assessed with regard to image quality, artefacts, signal-to-noise ratio (SNR), and signal-at-tenuation-to-noise ratio (delta SNR) of the non-ischaemic tissue. Visual assessment showed GRE-EPI images acquired at 4.7 T to suffer from distortion due to susceptibility artefacts. Artefacts were less marked with the SE and STE series. The GRE-EPI sequence gave the highest SNR and delta SNR. At 2.35 T, the SNR of the STE sequences was less than 3 and therefore did not allow construction of reliable signal-time curves. SE-EPI was best suited for perfusion-weighted imaging at high field strength thanks to its minimal distortion artefacts and high SNR. Using lower field strengths (2.35 T and less), susceptibility artefacts are reduced; GRE-EPI sequences are then best suited, because they have the highest SNR and T2* sensitivity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / blood supply
  • Brain Ischemia / diagnosis*
  • Contrast Media
  • Echo-Planar Imaging / instrumentation*
  • Gadolinium DTPA
  • Image Processing, Computer-Assisted / instrumentation*
  • Magnetic Resonance Imaging / instrumentation*
  • Rats
  • Rats, Wistar
  • Regional Blood Flow / physiology
  • Sensitivity and Specificity

Substances

  • Contrast Media
  • Gadolinium DTPA