T1 contrasts obtained using short-TR incoherent steady state gradient echo (GRE) methods are generally suboptimal, to which non-T1 factors in the signals play a major part. In this work, we proposed an augmented T1 -weighted (aT1 W) method to extract the signal ratio between routine GRE T1 W and proton density-weighted signals that effectively removes the non-T1 effects from the original T1 W signals, including proton density, T2 * decay, and coil sensitivity. A recently proposed multidimensional integration (MDI) technique was incorporated in the aT1 W calculation for better signal-to-noise ratio (SNR) performance. For comparison between aT1 W and T1 W results, Monte Carlo noise analysis was performed via simulation and on scanned data, and region-of-interest (ROI) analysis and comparison was performed on the system phantom. For brain scans, the image contrast, noise behavior, and SNR of aT1 W images were compared with routine GRE and inversion-recovery-based T1 W images. The proposed aT1 W method yielded saliently improved T1 contrasts (potentially > 30% higher contrast-to-noise ratio [CNR]) than routine GRE T1 W images. Good spatial homogeneity and signal consistency as well as high SNR/CNR were achieved in aT1 W images using the MDI technique. For contrast-enhanced (CE) imaging, aT1 W offered stronger post-CE contrast and better boundary delineation than T1 MPRAGE images while using a shorter scan time.
Keywords: GRE; MDI; T1W; aT1W; image contrast.
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