压缩感知技术在头颅磁共振血管成像中的应用研究

目的:探讨压缩感知技术在头颅时间飞跃法磁共振血管造影(TOF-MRA)中的应用价值,并比较不同加速因子对成像的影响。方法:选取在医院同时行头颅并行采集(PI)TOF-MRA和压缩感知(CS)TOF-MRA扫描的21例受试者,根据CS采用的加速因子系数(AF)4.6和10.3,分别设CS5和CS10,每例患者获得PI、CS5和CS10的3组TOF-MRA图像。定性分析3组图像的诊断质量,分支小血管显示能力,定量分析3组图像的信噪比(SNR)、对比噪声比(CNR)和血管边缘锐利度。结果:PI、CS5和CS10扫描时间分别为4 min 48 s、5 min 4 s和2 min 31 s。图像质量定性评价中CS5优于PI,差异有统计学意义(t=3.062,P<0.05),CS10与PI相当(P=0.086)。图像SNR和CNR定量评估中CS5优于CS10,差异有统计学意义(t=2.744,t=2.428;P<0.05);PI与CS差异无统计学意义。CS图像血管边缘锐利度优于PI,且CS5优于CS10,差异有统计学意义(t=3.729,P<0.05);CS5对分支小血管显示能力最佳。结论:CS技术可缩短头颅TOF-MRA扫描时间,提供与常规PI-TOF相当或更高质量的图像,具有很高的临床应用价值。

The applied research on the CS technique in intracranial MRA

Objective:To explore the applied value of compressed sensing(CS)technique in intracranial time-offlight MR angiography(TOF-MRA)and to compare the effects of different acceleration factor on imaging.Methods:Twenty-one receivers who underwent both parallel imaging MRA(PI-MRA)and CS TOF-MRA on brain were selected.According to the two acceleration factors(AF=4.6 and AF=10.3)that were adopted by CS TOF-MRA,the CS5 and CS 10 were set,and each patient obtained 3 groups of images(PI,CS5 and CS10).The diagnostic quality and the display capability of small branching vessels of 3 groups of images were qualitatively analyzed,and the signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)and the edge sharpness of intracranial arteries were quantitatively analyzed.Results:The scan times of PI,CS5 and CS10 were 4 minutes 48 seconds,5 minutes 4 seconds and 2 minutes 31 seconds respectively.In qualitative evaluation of image quality,CS5 was significantly superior to PI(t=3.062,P<0.05),and CS10 was significantly equivalent to PI(P=0.086).In the quantitative assessment of SNR and CNR of images,CS5 was significantly superior to CS10(t=2.744,t=2.428,P<0.05),while there was no statistical difference between PI and CS.The edge sharpness of intracranial arteries in CS group was significantly better than that of PI group,and that of CS5 was superior to that of CS10(t=3.729,P<0.05).CS5 had best display capability on(LSD-t=2.744,2.428),the small branching vessels.Conclusion:Compared with routine PI TOF-MRA,CS technique can shorten scan time of cerebral TOF-MRA,and can provide image with equivalent or higher quality.It has well applied value in clinical practice.