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Assessment of vessel permeability by combining dynamic contrast‐enhanced and arterial spin labeling MRI
Author(s) -
Liu HoLing,
Chang TingTing,
Yan FengXian,
Li ChengHe,
Lin YuShi,
Wong Alex M.
Publication year - 2015
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3297
Subject(s) - voxel , perfusion , blood flow , dynamic contrast , scanner , dynamic contrast enhanced mri , nuclear medicine , magnetic resonance imaging , gradient echo , biomedical engineering , arterial spin labeling , cerebral blood flow , nuclear magnetic resonance , chemistry , materials science , medicine , radiology , physics , optics , cardiology
The forward volumetric transfer constant ( K trans ), a physiological parameter extracted from dynamic contrast‐enhanced (DCE) MRI, is weighted by vessel permeability and tissue blood flow. The permeability × surface area product per unit mass of tissue (PS) in brain tumors was estimated in this study by combining the blood flow obtained through pseudo‐continuous arterial spin labeling (PCASL) and K trans obtained through DCE MRI. An analytical analysis and a numerical simulation were conducted to understand how errors in the flow and K trans estimates would propagate to the resulting PS. Fourteen pediatric patients with brain tumors were scanned on a clinical 3‐T MRI scanner. PCASL perfusion imaging was performed using a three‐dimensional (3D) fast‐spin‐echo readout module to determine blood flow. DCE imaging was performed using a 3D spoiled gradient‐echo sequence, and the K trans map was obtained with the extended Tofts model. The numerical analysis demonstrated that the uncertainty of PS was predominantly dependent on that of K trans and was relatively insensitive to the flow. The average PS values of the whole tumors ranged from 0.006 to 0.217 min −1 , with a mean of 0.050 min −1 among the patients. The mean K trans value was 18% lower than the PS value, with a maximum discrepancy of 25%. When the parametric maps were compared on a voxel‐by‐voxel basis, the discrepancies between PS and K trans appeared to be heterogeneous within the tumors. The PS values could be more than two‐fold higher than the K trans values for voxels with high K trans levels. This study proposes a method that is easy to implement in clinical practice and has the potential to improve the quantification of the microvascular properties of brain tumors. Copyright © 2015 John Wiley & Sons, Ltd.