Microvessel density estimation in the human brain by means of dynamic contrast-enhanced echo-planar imaging

Magn Reson Med. 2006 Nov;56(5):1145-50. doi: 10.1002/mrm.21052.


Animal studies have shown that in vivo estimates of microvessel density in the brain may be obtained from an MRI-measurable index (Q) provided that a sufficiently high dose of an intravascular paramagnetic contrast agent is employed. Q is determined from the shifts in the transverse relaxation rates induced by the contrast agent, and a high dose is required for the validity of analytic expressions relating Q to the microvessel density. However, the steady-state imaging techniques used in these prior investigations are not appropriate for humans, as the required contrast agent dose is too large. Here results of a pilot study with three subjects are reported. The results suggest that reliable Q measurements can be performed in the human brain at 1.5 T by using an interleaved spin-echo (SE)/gradient-echo (GE) echo-planar imaging (EPI) sequence and a bolus injection of a triple dose of Gd-DTPA. Lower- and upper-bound estimates for the microvessel density were derived from the Q-values, and were found to be in reasonable accord with previously cited values determined by histology.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Algorithms
  • Brain / blood supply*
  • Brain / pathology*
  • Contrast Media
  • Echo-Planar Imaging / methods*
  • Female
  • Gadolinium DTPA*
  • Humans
  • Image Enhancement / methods
  • Image Interpretation, Computer-Assisted / methods*
  • Male
  • Microcirculation / pathology*
  • Multiple Sclerosis / pathology*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Spin Labels


  • Contrast Media
  • Spin Labels
  • Gadolinium DTPA