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dc.contributor.authorKim, Jana
dc.contributor.authorMoestue, Siver Andreas
dc.contributor.authorBathen, Tone Frost
dc.contributor.authorKim, Eugene
dc.identifier.citationTomography. 2019, 5 (3), 308-319.nb_NO
dc.description.abstractEffective transverse relaxivity of gadolinium-based contrast agents is often neglected in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we assess time and tissue dependence of R2* enhancement and its impact on pharmacokinetic parameter quantification and treatment monitoring. Multiecho DCE-MRI was performed at 7 T on mice bearing subcutaneous TOV-21G human ovarian cancer xenografts (n 8) and on the transgenic adenocarcinoma of the mouse prostate (TRAMP) model (n 7). Subsequently, the TOV-21G tumor-bearing mice were treated with bevacizumab and rescanned 2 days later. Pharmacokinetic analysis (extended Tofts model) was performed using either the first echo signal only (standard singleecho DCE-MRI) or the estimated signal at TE 0 derived from exponential fitting of R2* relaxation (R2*- corrected). Neglecting R2* enhancement causes underestimation of Gd-DOTA concentration (peak enhancement underestimated by 9.4%–16% in TOV-21G tumors and 13%–20% in TRAMP prostates). Median Ktrans and ve were underestimated in every mouse (TOV-21G Ktrans: 11%–19%, TOV-21G ve: 5.3%–8.9%; TRAMP Ktrans: 8.6%–19%, TRAMP ve: 12%–21%). Bevacizumab treatment reduced Ktrans in all TOV-21G tumors after 48 hours. Treatment effect was significantly greater in all tumors after R2* correction (median change of 0.050 min1 in R2*-corrected Ktrans vs. 0.037 min1 in uncorrected Ktrans). R2* enhancement in DCEMRI is both time- and tissue-dependent and may not be negligible at 7 T in tissue with high Ktrans. This has consequences for the use of Ktrans and other DCE-MRI parameters as biomarkers, because treatment effect size can be underestimated when R2* enhancement is neglected.nb_NO
dc.publisherGrapho Publicationsnb_NO
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internasjonal*
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internasjonal*
dc.titleR2* Relaxation Affects Pharmacokinetic Analysis of Dynamic Contrast-Enhanced MRI in Cancer and Underestimates Treatment Response at 7 Tnb_NO
dc.typeJournal articlenb_NO
dc.description.localcode© 2019 The Authors. Published by Grapho Publications, LLC This is an open access article under the CC BY-NC-ND license (
cristin.unitnameInstitutt for sirkulasjon og bildediagnostikk
cristin.unitnameInstitutt for klinisk og molekylær medisin

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Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal
Med mindre annet er angitt, så er denne innførselen lisensiert som Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal