ELECTRONIC POSTER - ismrm

there were only minor distortions. In 5 patients complete removal of the lesion was already achieved by the time of iDSC-MRI. In the
remaining case tumor could be depicted that demonstrated identical perfusion ratio as in the preoperatively acquired scans. DSC-MRI
is technically feasable intraoperatively and enables a differentiation of residual tumor from contrast-enhancement caused by surgical
manipulation in these intraoperative MRIs.
Wednesday 13:30-15:30 Computer 63
13:30 4112. Comparison of Cerebral Blood Volume and Contrast Leakage Correction Efficiency
with Dynamic Susceptibility Contrast Enhanced Perfusion Imaging
Hiroyuki Kabasawa 1 , Malancha Hore 2 , Patrice Hervo 3 , Tetsuji Tsukamoto 1
1 Japan Applied Science Laboratory, GE Healthcare Japan, Hino, Tokyo, Japan; 2 MR Engineering, GE
Healthcare, Bangalore, India; 3 MR Clinical Development, GE Healthcare, Buc, France
Post-processing correction methods have been proposed to correct this contrast leakage effect in disrupted BBB and to obtain accurate
CBV estimation from DSC data. The estimated leakage effect from DSC can vary with the reference time course used in the postprocessing.
Here, we evaluated the impact of reference time course to estimate the leakage effect using numerical simulation and
clinical data. This study showed that appropriate selection of reference time course is an important factor to obtain reasonable contrast
leakage index using DSC MRI. Reference time course with wider width may introduce false positive signal in leakage map.
14:00 4113. Comparison of a Data Processing Method Accounting for Contrast Agent
Extravasation with the Pre-Load Approach in Bolus-Based CBV Estimates in Tumors
Irène Troprès 1,2 , Nicolas Pannetier, 23 , Sylvie D. Grand, 2,4 , Alexandre Krainik, 2,4 , Jean-
François Le Bas, 2,4 , Emmanuel L. Barbier, 23
1 Unité IRM 3T, IFR1, La Tronche - Grenoble, France; 2 Universite Grenoble 1, Grenoble, France; 3 U836,
INSERM, Grenoble, France; 4 Neuroradiology, Grenoble Hospital, Grenoble, France
Estimate of relative Cerebral Blood Volume (rCBV) obtained with DSC methods suffers from contrast agent (CA) extravasation in
brain tumors. The aim of this study is to compare a data processing method accounting for CA dilution with the pre-load approach. In
nine patients, a DSC protocol was performed twice within the same session. A gamma-variate fit was used to compute rCBV maps,
with and without considering the dilution. This study suggests that the dilution method is relevant when CA pre-load is performed and
that normalization of rCBV estimates by white matter values should be handled with care.
14:30 4114. Effects of Pre-Loading Dose on DSC-MRI with Contrast Agent Extravasation
Yi-Ying Wu 1,2 , Jyh-Wen Chai 1 , Chi-Chang Chen 1 , Ho-Ling Liu 2,3
1 Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan; 2 Institute of Medical
Physics and Imaging Science, Chang Gung University, Taoyuan, Taiwan; 3 MRI Center, Chang Gung Memorial
Hospital, Taoyuan, Taiwan
Disruption of blood-brain barriers in brain lesions usually causes difficulty in accurate quantification if rCBV in DSC-MRI. In this
study, a simulated model was proposed to evaluate the dependence of the pre-loading dose on the rCBV measurements. The results
showed an underestimate of rCBV without pre-loading or with low pre-loading dose at 1.5T. The underestimation was improved with
larger pre-loading dose. Significant overestimation of rCBV happened with pre-loading of contrast agents at 3.0T, particularly with
higher dose and a longer TE. In conclusion, this experiment provided important evidence that how the pre-loading dose affect the
accurate quantification of rCBV measurement.
15:00 4115. Modeling Relaxation Effects During Bolus Passage Through Leaky Vasculature
Using the Finite Perturber Method
David Bonekamp 1 , Barney Douglas Ward 2 , Richard Leigh 3 , Peter B. Barker 1 , Arvind P.
Pathak 1
1 Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States;
2 Department of Biophysics, Medical College of Wisconsin,, Milwaukee, WI, United States; 3 Department of
Neurology, Johns Hopkins University, Baltimore, MD, United States
Extravasation of contrast during bolus passage alters the dynamic susceptibility contrast MRI signal. Reliable quantification of
microvascular parameters in common brain pathologies depends on the ability to account for effects of leaky vasculature. Analytical
solutions are hampered by mathematical approximations. We extend the computational finite perturber model (FPM) by incorporating
a compartmental model to simulate arterial bolus passage and contrast agent extravasation. We find that known characteristics of
DSC-MRI signal curves can be successfully modeled. This approach provides a powerful framework to optimize imaging sequences
and to examine the complicated interaction of pathological, physiological and biophysical phenomena that result in the observed DSC-
MRI signal.