基于敏感性编码及压缩感知技术优化颅脑MR三维相位对比静脉造影成像序列

Optimization of MR sequences of craniocerebral three-dimensionalphase-contrast magnetic resonance venogram based on sensitivitycoding and compressed sensing technology

目的 对比以不同加速因子(acceleration factors, AF)敏感性编码(SENSE)与压缩感知(CS)及SENSE组合(CS-SENSE)技术所获颅脑三维相位对比MR静脉造影(3D PC-MRV)图像质量,以优化序列。方法 前瞻性对26名健康志愿者以AF分别为6和9的SENSE技术,以及AF分别为9、12、15及18的CS-SENSE技术采集颅脑3D PC-MRV,并依次记为MRV_(SENSE6)、MRV_(SENSE9)、MRV_(CS9)、MRV_(CS12)、MRV_(CS15)和MRV_(CS18)。比较上矢状窦(SSS)和左(L)、右(R)侧乙状窦(SiS)在各组3D PC-MRV软组织图中,以及SSS和左(L)、右(R)侧横窦(TRS)的信噪比(SNR)和对比度噪声比(CNR)在各组3D PC-MRV幅度图中的差异;对比整体图像质量及静脉窦和脑静脉结构可视化主观评分。结果 3D PC-MRV软组织图中,除CNR_(R-SiS)外,MRV_(SENSE6)的SNR_(SSS)、CNR_(SSS)、SNR_(R-SiS)及SNR_(L-SiS)均高于MRV_(SENSE9)(P均<0.05),MRV_(CS9)、MRV_(CS12)及MRV_(CS15)图像各参数均高于MRV_(SENSE9)(P均<0.05)而与MRV_(SENSE6)差异均无统计学意义(P均>0.05),MRV_(CS18)的SNR_(R-SiS)和SNR_(L-SiS)均低于MRV_(SENSE6),CNR_(L-SiS)高于MRV_(SENSE9),SNR_(SSS)、SNR_(R-SiS)及SNR_(L-SiS)低于MRV_(CS9)及MRV_(CS12),SNR_(R-SiS)低于MRV_(CS15)(P均<0.05),其余参数差异均无统计学意义(P均>0.05);3D PC-MRV幅度图中,MRV_(SENSE6)各参数均高于MRV_(SENSE9),MRV_(CS9)及MRV_(CS12)均高于MRV_(SENSE6),MRV_(CS9)、MRV_(CS12)、MRV_(CS15)及MRV_(CS18)均高于MRV_(SENSE9),MRV_(CS15)及MRV_(CS18)均低于MRV_(CS9),MRV_(CS18)低于MRV_(CS12)(P均<0.05),其余各参数差异均无统计学意义(P均>0.05);对图像质量的主观评分结果与上述客观评价结果相似。结论 相比SENSE,基于CS-SENSE的3D PC-MRV可在更短时间内获得质量更优的颅脑静脉图像;AF取12为优化序列。

Objective To compare image quality of craniocerebral three-dimensional phase-contrast MR venogram(3D PC-MRV)acquired using sensitivity encoding(SENSE)with different acceleration factors(AF)and compressed sensing(CS)combined with SENSE(CS-SENSE).Methods Craniocerebral 3D PC-MRV were prospectively acquired in 26 healthy volunteers,including SENSE with AF of 6 and 9,CS-SENSE with AF of 9,12,15 and 18,respectively,which were recorded as MRV_(SENSE6),MRV_(SENSE9),MRV_(CS9),MRV_(CS12),MRV_(CS15) and MRV_(CS18).Signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of the superior sagittal sinus(SSS),left(L)and right(R)sigmoid sinuses(SiS)on 3D PC-MRV soft tissue maps,so were those of SSS,left and right transverse sinuses(TRS)on amplitude maps.The objective evaluation results and subjective scores of overall imaging quality and visualization of venous sinuses and cerebral veins of 3D PC-MRV were also compared.Results On 3D PC-MRV soft tissue maps,SNR_(SSS),CNR_(SSS),SNR_(R-SiS) and SNR L-SiS of MRV_(SENSE6) were higher than those of MRV_(SENSE9)(all P<0.05).Parameters of MRV_(CS9),MRV_(CS12) and MRV_(CS15),except for CNR_(R-SiS),were higher than those of MRV_(SENSE9)(all P<0.05),while no significant difference of MRV_(SENSE6) was found(all P>0.05).SNR_(R-SiS) and SNR L-SiS of MRV_(CS18) were lower than those of MRV_(SENSE6),with CNR_(L-SiS) higher than MRV_(SENSE9) and SNR_(SSS),SNR_(R-SiS) as well as SNR L-SiS lower than MRV_(CS9) and MRV_(CS12),and SNR_(R-SiS) was lower than MRV_(CS15)(all P<0.05).No significant difference of the other parameters was found(all P>0.05).For objective evaluation on 3D PC-MRV amplitude maps,parameters of MRV_(SENSE6) was higher than MRV_(SENSE9),MRV_(CS9) and MRV_(CS12) were higher than MRV_(SENSE6),MRV_(CS9),MRV_(CS12),MRV_(CS15) and MRV_(CS18) were higher than MRV_(SENSE9).MRV_(CS15) and MRV_(CS18) were lower than MRV_(CS9),MRV_(CS18) was lower than MRV_(CS12)(all P<0.05),while no significant difference of the other parameters was found(all P>0.05).The results of subjective and objective evaluation on 3D PC-MRV images were similar.Conclusion Compared with SENSE,better imaging quality of craniocerebral vein could be obtain using 3D PC-MRV based on CS-SENSE with shorter time,especially with AF of 12.