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Brain capillary transit time heterogeneity in healthy volunteers measured by dynamic contrast‐enhanced T 1 ‐weighted perfusion MRI
Author(s) -
Larsson Henrik B.W.,
Vestergaard Mark B.,
Lindberg Ulrich,
Iversen Helle K.,
Cramer Stig P.
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25488
Subject(s) - cerebral blood flow , dynamic contrast enhanced mri , nuclear medicine , perfusion scanning , medicine , blood flow , perfusion , interquartile range , magnetic resonance imaging , radiology
Purpose Capillary transit time heterogeneity, measured as CTH, may set the upper limit for extraction of substances in brain tissue, e.g., oxygen. The purpose of this study was to investigate the feasibility of dynamic contrast‐enhanced T 1 weighted MRI (DCE‐MRI) at 3 Tesla (T), in estimating CTH based on a gamma‐variate model of the capillary transit time distribution. In addition, we wanted to investigate if a subtle increase of the blood–brain barrier permeability can be incorporated into the model, still allowing estimation of CTH. Materials and Methods Twenty‐three healthy subjects were scanned at 3.0T MRI system applying DCE‐MRI and using a gamma‐variate model to estimate CTH as well as cerebral blood flow (CBF), cerebral blood volume (CBV), and permeability of the blood–brain barrier, measured as the influx constant K i . For proof of principle we also investigated three patients with recent thromboembolic events and a patient with a high grade brain tumor. Results In the healthy subjects, we found a narrow symmetric delta‐like capillary transit time distribution in basal ganglia gray matter with median CTH of 0.93 s and interquartile range of 1.33 s. The corresponding residue impulse response function was compatible with the adiabatic tissue homogeneity model. In two patients with complete occlusion of the internal carotid artery and in the patient with a brain tumor CTH was increased with values up to 6 s in the affected brain tissue, with an exponential like residue impulse response function. Conclusion Our results open the possibility of characterizing brain perfusion by the capillary transit time distribution using DCE‐MRI, theoretically a determinant of efficient blood to brain transport of important substances. Level of Evidence : 2 J. MAGN. RESON. IMAGING 2017;45:1809–1820