Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) evaluation of preoperative therapy for extremity soft tissue sarcomas (STS).

10098 Backgound:DCE-MRI detects changes in tumor perfusion and may be useful in assessing response to therapy. The “Shutter-Speed” Model (SSM) for DCE-MRI pharmacokinetic (PK) analysis may be more sensitive than the Standard (Tofts) Model (SM) as it admits the fact that equilibrium transcytolemmal water exchange is not infinitely fast. We performed a feasibility study of SSM DCE-MRI in patients receiving preoperative therapy for STS, including assessment of a new DCE-MRI PK parameter ΔKtrans [≡Ktrans (SSM) – Ktrans (SM)], a measure of the finite water exchange effects on DCE-MRI PK analysis. Methods: Subjects with >5 cm, grade 2-3, extremity/body wall STS received preoperative sorafenib (S) + epirubicin/ifosfamide (E/I) or E/I alone. All patients received 28 Gy radiation in 8 fractions. DCE-MRI was performed at baseline [time point zero (TP0)], after 2 weeks S or E/I (TP1), and after completion of preoperative therapy (TP2). The SM and SSM were used for PK modeling on tumor region of interest (ROI) and pi...