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

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-attenuation-to-noise ratio (ΔSNR) 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 ΔSNR. 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.

[1]  R R Edelman,et al.  Cerebral blood flow: assessment with dynamic contrast-enhanced T2*-weighted MR imaging at 1.5 T. , 1990, Radiology.

[2]  C. Sotak,et al.  Diffusion and Perfusion Magnetic Resonance Imaging Studies to Evaluate a Noncompetitive N‐Methyl‐D‐aspartate Antagonist and Reperfusion in Experimental Stroke in Rats , 1993, Stroke.

[3]  M. Cohen,et al.  Echoplanar MR imaging of the liver in patients with focal hepatic lesions: quantitative analysis of images made with various pulse sequences. , 1994, AJR. American journal of roentgenology.

[4]  P. Weinstein,et al.  Reversible middle cerebral artery occlusion without craniectomy in rats. , 1989, Stroke.

[5]  R. Turner,et al.  Echo‐planar imaging of diffusion and perfusion , 1991, Magnetic resonance in medicine.

[6]  P. Mansfield,et al.  Line scan proton spin imaging in biological structures by NMR. , 1976, Physics in medicine and biology.

[7]  R. Turner,et al.  Echo-planar imaging: magnetic resonance imaging in a fraction of a second. , 1991, Science.

[8]  M E Moseley,et al.  High-Speed MR Imaging of Ischemic Brain Injury following Stenosis of the Middle Cerebral Artery , 1993, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[9]  J. Pekar,et al.  Imaging of diffusion and microcirculation with gradient sensitization: Design, strategy, and significance , 1991, Journal of magnetic resonance imaging : JMRI.

[10]  Robert Turner,et al.  Diffusion and perfusion magnetic resonance imaging , 1992 .

[11]  S. Heiland,et al.  Early MR detection of experimentally induced cerebral ischemia using magnetic susceptibility contrast agents: comparison between gadopentetate dimeglumine and iron oxide particles. , 1995, AJNR. American journal of neuroradiology.

[12]  J. Kurhanewicz,et al.  Diffusion-weighted MR imaging of acute stroke: correlation with T2-weighted and magnetic susceptibility-enhanced MR imaging in cats. , 1990, AJNR. American journal of neuroradiology.

[13]  V. Runge,et al.  Assessment of cerebral perfusion by first-pass, dynamic, contrast-enhanced, steady-state free-precession MR imaging: an animal study. , 1993, AJR. American journal of roentgenology.

[14]  E F Halpern,et al.  Cerebral blood volume maps of gliomas: comparison with tumor grade and histologic findings. , 1994, Radiology.

[15]  D G Norris,et al.  Quantitative measurement of regional blood flow with gadolinium diethylenetriaminepentaacetate bolus track NMR imaging in cerebral infarcts in rats: validation with the iodo[14C]antipyrine technique. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[16]  R R Edelman,et al.  In vivo measurement of water diffusion in the human heart , 1994, Magnetic resonance in medicine.

[17]  B. Rosen,et al.  Perfusion imaging with NMR contrast agents , 1990, Magnetic resonance in medicine.

[18]  A Macovski,et al.  Echo‐planar spin‐echo and inversion pulses , 1993, Magnetic resonance in medicine.

[19]  M. Moseley,et al.  Detection with echo‐planar MR imaging of transit of susceptibility contrast medium in a rat model of regional brain ischemia , 1991, Journal of magnetic resonance imaging : JMRI.

[20]  D Chien,et al.  Perfusion imaging by nuclear magnetic resonance. , 1989, Magnetic resonance quarterly.

[21]  C. Patlak,et al.  Susceptibility changes following bolus injections , 1993, Magnetic resonance in medicine.

[22]  M. Moseley,et al.  Real‐time observation of transient focal ischemia and hyperemia in cat brain , 1992, Magnetic resonance in medicine.

[23]  B. Rosen,et al.  Dynamic imaging with lanthanide chelates in normal brain: Contrast due to magnetic susceptibility effects , 1988, Magnetic resonance in medicine.

[24]  Normal heart: evaluation with echo-planar MR imaging. , 1994, Radiology.

[25]  R. S. Hinks,et al.  Spin‐echo and gradient‐echo epi of human brain activation using bold contrast: A comparative study at 1.5 T , 1994, NMR in biomedicine.

[26]  C T Moonen,et al.  Single‐shot localized echo‐planar imaging (STEAM‐EPI) at 4.7 tesla , 1990, Magnetic resonance in medicine.

[27]  M E Moseley,et al.  Echo-planar perfusion-sensitive MR imaging of acute cerebral ischemia. , 1993, Radiology.

[28]  B. Rosen,et al.  Susceptibility contrast imaging of cerebral blood volume: Human experience , 1991, Magnetic resonance in medicine.

[29]  M E Moseley,et al.  Early detection of ischemic injury: comparison of spectroscopy, diffusion-, T2-, and magnetic susceptibility-weighted MRI in cats. , 1990, Acta neurochirurgica. Supplementum.

[30]  B. Rosen,et al.  MR Contrast Due to Microscopically Heterogeneous Magnetic Susceptibility: Numerical Simulations and Applications to Cerebral Physiology , 1991, Magnetic resonance in medicine.