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Blood oxygenation level dependent, blood volume, and blood flow responses to carbogen and hypoxic hypoxia in 9L rat gliomas as measured by MRI
Author(s) -
Jerome Neil P.,
Hekmatyar S. Khan,
Kauppinen Risto A.
Publication year - 2014
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.24097
Subject(s) - carbogen , hypoxia (environmental) , oxygenation , medicine , blood flow , blood volume , nuclear medicine , pathology , cardiology , oxygen , chemistry , organic chemistry
Purpose To study vascular responsiveness to hypoxia and hypercarbia together with vessel size index (VSI) in a 9L rat glioma (n = 11) using multimodal MRI. Materials and Methods VSI was determined using T 2 and T 2 * MRI following AMI‐227 contrast agent. Blood oxygenation level dependent (BOLD) signal response was determined using T 2 EPI MRI, blood volume changes using AMI‐227 and blood flow by means of continuous arterial spin labeling. Results VSI in the cortex, tumor rim, and core of 2.2 ± 1.0, 18.2 ± 5.4, and 23.9 ± 14.7 μm, respectively, showing a larger average vessel size in glioma than in the brain parenchyma. BOLD and blood volume signal changes to hypoxia and hypercapnia were much more profound in the tumor rim than the core. Hypoxia led to rim BOLD signal change that was larger in amplitude and it attained the low value much faster than either core or brain cortex. The vasculature in the rim appears more responsive to respiratory challenges in terms of volume adaptation than the core. Blood flow values within the gliomas were much lower than in the contralateral brain. Neither hypercarbia nor hypoxia had an effect on the tumor blood flow. Conclusion Vascular responses of 9L gliomas to respiratory challenge, in particular hypoxia, are heterogeneous between the core and rim zones, potentially offering a means to classify and separate intratumor tissues with differing hemodynamic characteristics. J. Magn. Reson. Imaging 2014;39:110–119. © 2013 Wiley Periodicals, Inc.