Carotid wall imaging with 3D_T2_FFE: sequence parameter optimization and comparison with 3D_T2_SPACE

Similar to sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE), T2-weighted fast field echo (FFE) also has a black blood effect and a high imaging efficiency. The purpose of this study was to optimize 3D_T2_FFE and compare it with 3D_T2_SPACE for carotid imaging. The scanning parameter of 3D_T2_FFE was optimized for the imaging of the carotid wall. Twenty healthy volunteers and 10 patients with carotid plaque underwent cervical 3D_T2_FFE and 3D_T2_SPACE examinations. The signal-to-noise ratios of the carotid wall (SNR(wall)) and lumen (SNR(lumen)), and the contrast-to-noise ratios between the wall and lumen (CNR(wall_lumen)) were compared. The incidence of the residual flow signal at the carotid bifurcation and the grades of flow voids in the cerebellopontine angle region in the two sequences were also compared. The reproducibility of the two sequences was tested. No significant difference was observed between the two sequences in terms of the SNR(wall) of healthy individuals and patients (P = 0.132 and 0.102, respectively). The SNR(lumen) in the 3D_T2_FFE images was lower than that in the 3D_T2_SPACE images. No significant difference was observed between the two sequences in terms of the CNR(wall-lumen). The incidence of the residual flow signal at the carotid bifurcation in 3D_T2_FFE was significantly lower than that in 3D_T2_SPACE. The grades of flow suppression in the cerebellopontine angle region in 3D_T2_SPACE was lower than that in 3D_T2_FFE. Both sequences showed excellent inter-and intra-observer reproducibility. Compared to 3D_T2_SPACE, 3D_T2_FFE showed stronger flow suppression while maintaining good imaging quality, which can be used as an alternative tool for carotid imaging.