Published in:
01-12-2015 | Research Article
Effect of \( T_{2}^{*} \) correction on contrast kinetic model analysis using a reference tissue arterial input function at 7 T
Published in: Magnetic Resonance Materials in Physics, Biology and Medicine | Issue 6/2015
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Objectives
We aimed to investigate the effect of \( T_{2}^{*} \) correction on estimation of kinetic parameters from T
1-weighted dynamic contrast enhanced (DCE) MRI data when a reference-tissue arterial input function (AIF) is used.
Materials and methods
DCE-MRI data were acquired from seven mice with 4T1 mouse mammary tumors using a double gradient echo sequence at 7 T. The AIF was estimated from a region of interest in the muscle. The extended Tofts model was used to estimate pharmacokinetic parameters in the enhancing part of the tumor, with and without \( T_{2}^{*} \) correction of the lesion and AIF. The parameters estimated with \( T_{2}^{*} \) correction of both the AIF and lesion time-intensity curve were assumed to be the reference standard.
Results
For the whole population, there was significant difference (p < 0.05) in transfer constant (K
trans) between \( T_{2}^{*} \) corrected and not corrected methods, but not in interstitial volume fraction (v
e). Individually, no significant differences were found in K
trans and v
e of four and six tumors, respectively, between the \( T_{2}^{*} \) corrected and not corrected methods. In contrast, K
trans was significantly underestimated, if the \( T_{2}^{*} \) correction was not used, in other tumors for which the median K
trans was larger than 0.4 min−1.
Conclusion
\( T_{2}^{*} \) effect on tumors with high K
trans may not be negligible in kinetic model analysis, even if AIF is estimated from reference tissue where the concentration of contrast agent is relatively low.