Blood-Brain Barrier Permeability of Normal Appearing White Matter in Patients with Vestibular Schwannoma:A New Hybrid Approach for Analysis of T1W DCE-MRI

摘要

Purpose To develop and assess a “hybrid” method that combines a first-pass analytical approach and the Patlak plot (PP) to improve assessment of low blood–brain barrier permeability from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data. Materials and Methods Seven patients with vestibular schwannoma were enrolled. T1-W DCE imaging was acquired on a 1.5T scanner. Normal-appearing white matter (NAWM) was divided into four regions of interest (ROIs) based on the magnitude of changes in longitudinal relaxation rate (ΔR1) after gadolinium administration. Kinetic analysis of ROI-averaged contrast agent concentration curves was performed using both the conventional PP and the hybrid method. Computer simulated uptake curves that resemble those from NAWM were analyzed with both methods. Percent deviations (PD) of the “measured” values from the “true” values were calculated to evaluate accuracy and precision of the two methods. Results The simulation showed that, at a noise level of 4% (a noise level similar to the in vivo data) and using a signal intensity (SI) averaging scheme, the new hybrid method achieved a PD of 0.9 ± 2.7% for vp, and a PD of –5.4 ± 5.9% for Ktrans. In comparison, the PP method obtained a PD of 3.6 ± 11.3% for vp, and –8.3 ± 12.8% for Ktrans. One-way analyses of variance (ANOVAs) showed significant variations from the four WM regions (P < 10−15 for ΔR1; P < 10−6 for Ktrans; P < 10−4 for vp). Conclusion Both computer simulation and in vivo studies demonstrate improved reliability in vp and Ktrans estimates with the hybrid method.