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Microvessel density estimation in the human brain by means of dynamic contrast‐enhanced echo‐planar imaging
Author(s) -
Jensen Jens H.,
Lu Hanzhang,
Inglese Matilde
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21052
Subject(s) - contrast (vision) , nuclear magnetic resonance , microvessel , echo time , bolus (digestion) , spin echo , magnetic resonance imaging , nuclear medicine , relaxation (psychology) , chemistry , physics , medicine , radiology , pathology , anatomy , optics , immunohistochemistry
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. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.