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Vessel size index measurements in a rat model of glioma: comparison of the dynamic (Gd) and steady‐state (iron‐oxide) susceptibility contrast MRI approaches
Author(s) -
Pannetier Nicolas,
Lemasson Benjamin,
Christen Thomas,
Tachrount Mohamed,
Troprès Irène,
Farion Régine,
Segebarth Christoph,
Rémy Chantal,
Barbier Emmanuel L.
Publication year - 2012
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.1734
Subject(s) - contrast (vision) , steady state (chemistry) , glioma , nuclear magnetic resonance , dynamic contrast , index (typography) , iron oxide , chemistry , magnetic resonance imaging , nuclear medicine , materials science , physics , medicine , radiology , computer science , cancer research , metallurgy , optics , world wide web
Vessel size index (VSI), a parameter related to the distribution of vessel diameters, may be estimated using two MRI approaches: (i) dynamic susceptibility contrast (DSC) MRI following the injection of a bolus of Gd‐chelate. This technique is routinely applied in the clinic to assess intracranial tissue perfusion in patients; (ii) steady‐state susceptibility contrast with USPIO contrast agents, which is considered here as the standard method. Such agents are not available for human yet and the steady‐state approach is currently limited to animal studies. The aim is to compare VSI estimates obtained with these two approaches on rats bearing C6 glioma (n = 7). In a first session, VSI was estimated from two consecutive injections of Gd‐Chelate (Gd 1 and Gd 2 ). In a second session (4 hours later), VSI was estimated using USPIO. Our findings indicate that both approaches yield comparable VSI estimates both in contralateral (VSI{USPIO} = 7.5 ± 2.0 µm, VSI{Gd 1 } = 6.5 ± 0.7 µm) and in brain tumour tissues (VSI{USPIO} = 19.4 ± 7.1 µm, VSI{Gd 1 } = 16.6 ± 4.5 µm). We also observed that, in the presence of BBB leakage (as it occurs typically in brain tumours), applying a preload of Gd‐chelate improves the VSI estimate with the DSC approach both in contralateral (VSI{Gd 2 } = 7.1 ± 0.4 µm) and in brain tumour tissues (VSI{Gd 2 } = 18.5 ± 4.3 µm) but is not mandatory. VSI estimates do not appear to be sensitive to T 1 changes related to Gd extravasation. These results suggest that robust VSI estimates may be obtained in patients at 3 T or higher magnetic fields with the DSC approach. Copyright © 2011 John Wiley & Sons, Ltd.