基于螺旋成像TOF-MRA在颅内动脉成像中的应用研究

Value of intracranial time-of-flight magnetic resonance angiography based on spiral imaging

目的以压缩感知(CS)重建的时间飞跃法磁共振血管造影(TOF-MRA)(MRACS)为参考,探讨基于螺旋成像技术的MR血管成像(MRA_(spiral))在颅内血管成像中的应用价值。方法2021年5月29日—2022年6月11日,前瞻性收集49例怀疑脑血管病变患者的头颅MRA图像。采集序列CS敏感度编码为4加速的TOF-MRA(MRA_(CS4))和MRA_(spiral)(采集窗口τ分别为4、6、8、12)。在大脑前动脉(ACA)、大脑中动脉(MCA)、大脑后动脉(PCA)的近段和远段绘制兴趣区。以胼胝体为背景计算比值(CR)。由两名经验丰富的放射科医生分别对图像质量和诊断价值进行定性分析。采用单因素重复测量方差分析比较CR值的差异,Friedman检验比较定性分析的差异。结果在远段分支,PCA在MRA_(τ6)的CR值(2.61±1.09)低于MRA_(CS4)(3.16±1.62)(P=0.014)。余MRA_(spiral)图像的CR值(MRA_(τ4):2.73±1.45,MRA_(τ8):2.78±1.28,MRAτ12:2.64±1.43)与MRA_(CS4)的CR值无显著性差异(P>0.05)。在远段血管显示方面,MRA_(τ4)(4.78±0.41)、MRA_(τ6)(4.77±0.42)及MRA_(τ8)(4.55±0.52)明显优于MRA_(CS4)(4.28±0.52)(P<0.005)。在颅内近段血管显影方面,MRA_(CS4)显示优于MRA_(spiral)。结论MRA_(spiral)对颅内远段血管的显示优于MRACS,可更好地评估颅内动脉狭窄程度,同时MRA_(τ8)可以在保证图像质量的同时减少采集时间。

Objective To assess the value of intracranial time-of-flight magnetic resonance angiography(MRA)based on spiral imaging technology(MRA_(spiral))compared to compressed sensing(CS)reconstruction(MRACS).Methods From 29 May 2021 to 11 June 2022,brain MRA of 49 patients with suspected cerebrovascular disease was prospectively analyzed.MRA sequences with CS factor of 4(MRA_(CS4))and MRA_(spiral)(the acquisition windowτis 4,6,8,12)were acquired.The regions of interest were placed in the proximal and distal segments of the anterior cerebral artery,middle cerebral artery,and posterior cerebral artery(PCA)to calculate the contrast ratio(CR)with the corpus callosum as the background on both sequences.Qualitative analysis of image quality and diagnostic feasibility were performed independently by two experienced radiologists.One-way repeated measures ANOVA analysis was used to compare the differences in CR values and Friedman test was used to evaluate the differences in qualitative analysis.Results The CR value in the distal PCA(2.61±1.09)of MRA_(τ6)was significantly lower(P=0.014)than that of MRA_(CS4)(3.16±1.62).The CR values of the other MRA_(spiral)images(MRA_(τ4):2.73±1.45,MRA_(τ8):2.78±1.28,MRAτ12:2.64±1.43)were not significantly different from those of MRA_(CS4)(P>0.05).The CR values in the MRA_(τ4)(4.78±0.41),MRA_(τ6)(4.77±0.42)and MRA_(τ8)(4.55±0.52)were significantly better than MRA_(CS4) in distal vascular visualization(P<0.005).MRA_(CS4) showed better performance than MRA_(spiral)in proximal vessels(P>0.005).Conclusion MRA_(spiral)is superior to MRACS in displaying distal intracranial vessels,allowing for a better assessment of the degree of intracranial vascular stenosis.MRA_(τ8)can reduce acquisition time while ensuring image quality.