Perfusion imaging provides a more complete assessment of brain tumor hemodynamics and may prove particularly useful in the diagnosis and treatment of brain tumors. A combined spin- and gradient-echo (SAGE) approach, consisting of two gradient echoes (GE), two asymmetric spin echoes and one true spin echo (SE), was proposed as a means to assess perfusion (including the total and microvascular blood flow and blood volume), vessel size, and permeability (through the extraction of DR1 DCE-MRI data).¹ A key advantage of SAGE is that contrast agent (CA)-induced T₁ leakage effects can be removed through the use of multiple echoes, thereby improving the reliability of tumor blood volume measurements.^2,3 SAGE also enables the estimation of the transverse relaxivity at tracer equilibrium (TRATE), a new DSC-MRI parameter that reflects cellular features (cell density, polydispersity, and cell size).⁴ We recently proposed and validated in pre-clinical tumor models a simplified SAGE approach that employs a combined dual GE and SE pulse sequence and an analytic solution for computing T₁-insensitive ΔR₂^* and ΔR₂ that significantly increased the computational efficiency.⁵ The combination of the simplified SAGE data with our recently validated T₂^* leakage correction method⁶ provides a clinically efficient and robust approach for the derivation of leakage corrected blood volume maps in brain tumors. Taken together, the simplified SAGE approach provides a clinically feasible strategy for the simultaneous assessment tumor perfusion, permeability and cellularity. The goals of this study are to further validate simplified SAGE in glioma and brain metastases patients and to demonstrate its utility for assessing Bevacizumab treatment response. Data were acquired at 3T (Achieva, Philips Healthcare) in high-grade glioma patients before and after Bevacizumab treatment (n = 4) and in brain metastases patients (n = 7). DSC-MRI data were acquired using a SAGE-EPI sequence (TR = 1.8s, TEs = 8.8/26/55/72/88ms, SENSE = 2, voxel size = 2.5 x 2.5 x 5.0mm³, 15 slices, 7.5min duration) before, during, and after administration of 0.1 mmol/kg Gd-DTPA. The T₁-corrected ∆R₂ and ∆R₂^* were obtained analytically from the GE and SE signals using the sSAGE equations⁵ and were subsequently corrected by subtracting the ΔR1-derived veCe(t), scaled by the equilibrium transverse relaxivity, from the T₁-corrected ΔR₂ and ∆R₂^*.⁶ The corrected DSC perfusion data are compared to uncorrected DSC data using the 2^nd GE and the SE. The derived hemodynamic parameters include GE and SE CBV, mean vessel diameter (mVD), TRATE, K^trans, and v_e. Figure 1 shows example GE (top) and SE (bottom) DSC data in a high-grade glioma prior to treatment with Bevacizumab. In tumor, T₁-shortening effects due to Gd-DTPA extravasation manifest as lower post-bolus ∆R₂^* and ∆R₂ for the uncorrected single echo data. The SAGE and sSAGE curves, both corrected for T₁ leakage effects, do not exhibit reduced post-bolus ∆R₂^* and are in close agreement. Further correction for T₂ and T₂^* leakage effects yielded similar curves for sSAGE and SAGE ∆R₂^* and ∆R₂. Conventional DSC-MRI provides GE CBV maps that are sensitive to T₁-leakage effects, manifest here as a substantially reduced tumor CBV (Figure 2). The sSAGE and SAGE maps are corrected for T₁, T₂, and T₂^* leakage effects and are in close agreement. The TRATE maps are sensitive to an array of cellular features and may provide unique information regarding the tumor cellular environment. This method also provides ∆R₁ curves that can be used in standard DCE pharmacokinetic models to provide Ktrans maps. The simplified SAGE technique leverages multiple echoes to provide T1-insensitive GE and SE hemodynamic parameters, combined with a simple method to correct for remaining T2 and T2* leakage effects. This method is in close agreement with the more time-consuming conventional SAGE method. The use of this multi-echo sSAGE approach, combined with robust processing strategies for correction of leakage effects, could facilitate more rapid clinical translation and adoption of DSC-MRI for brain tumor imaging. DSC-MRI with the sSAGE approach provides a wealth of information about tumor vascularity, vessel size and permeability, and cellular characteristics, which has important implications for brain tumor patient management.