增强3D STIR序列在3.0T MRI腰骶神经根成像中的图像质量评估和应用价值讨论

Assessment of the quality of images and the value of contrast enhanced 3D STIR sequence to display lumbosacral nerve root

目的研究探讨使用3D STIR序列行腰骶神经根扫描中,静注GD-DTPA对比剂在显示神经根形态,以及背景抑制效果两方面探讨增强扫描在腰骶神经根成像中的优势和价值。方法对随机的20例行腰椎平扫加增强受检者进行两次3D STIR冠状位扫描,两次扫描分别在注射GD-DTPA对比剂前后进行,前后使用的序列设置相同,将使用平扫序列扫描得出的图像作为对照组,而增强扫描得到的图像作为实验组,扫描完成后在原始图像中分别在同一断层内测量增强前后3D STIR序列中的神经根信号强度(SI神经根),腰大肌信号强度(SI肌肉),肾脏信号强度(SI肾脏),并计算出神经根/腰大肌信号强度比(SI神经/肌肉),应用SPSS 22.0对两组数据分别进行t检验;通过4等级评分法比较两组序列对神经根形态的显示以及背景抑制情况。结果实验组中SI神经根(2157.750±1102.125)明显高于对照组SI神经根(1507.785±568.875),实验组中SI肌肉(170.335±121.665)、SI肾脏(100.370±75.860)等背景信号强度均低于对照组中的SI肌肉(275.520±201.480)和SI肾脏(505.330±392.260),实验组中神经肌肉信号强度比SI神经/SI肌肉(14.055±8.210)高于对照组(7.520±3.590),经过t检验上述差异均具有统计学意义(P<0.05)。实验组中对于腰骶丛神经的形态观察(2.167±0.516 vs 1.899±0.343,P<0.01)以及背景抑制的评分(2.242±0.453 vs 1.548±0.533,P<0.01)均高于对照组。结论增强3D STIR序列相对平扫序列,神经根信号强度更高,对神经根解剖形态细节的显示能力更强,同时对比平扫具有更好的背景抑制效果,可以作为诊断腰骶神经根疾病的一种更理想的影像学检查方法。

Objective To explore the effect of 3 D STIR sequence in contrast enhanced scan of lumbosacral nerve root and to analyze the advantage and value of 3 D STIR sequence in lumbosacral nerve root from the aspects of displaying nerve root and background suppression. Methods We collected the coronal pictures of 20 random patients in pre-and post-contrast scanning of lumbar using the same sequence. Pre-contrast scanning will be treated as control group while post-contrast scanning being experimental group. After scanning,the signal strength of nerve root（ SI nerve root）,psoas major and kidney and the nerve root/psoas major signal intensity ratio（ SI nerve/muscle） would be measured respectively. All data of two groups were analyzed using t-test.Moreover,the display of nerve root and the morphology of background would be compared through 4-grade evaluation method. Results SI nerve root（ 2157. 750 ± 1102. 125） and SI nerve/muscle（ 14. 055 ± 8. 210） of experimental group were obviously higher than control group[SI nerve root（ 1507. 785 ± 568. 875）,SI nerve/muscle（ 7. 520 ± 3. 590） ]. While,SI muscle（ 170. 335± 121. 665） and SI kidney（ 100. 370 ± 75. 860） of experimental group were lower than control group [SI muscle（ 275. 520 ±201. 480）,SI kidney（ 505. 330 ± 392. 260） ]. P values less than 0. 5 were considered to indicate a statistically significant difference. The score of morphology observation（ 2. 167 ± 0. 516 vs 1. 899 ± 0. 343,P〈0. 01） background suppression（ 2. 242 ±0. 453 vs 1. 548 ± 0. 533,P〈0. 01） of experimental group were also higher than control group. Conclusion Nerve root signal strength is higher and background inhibition effect is better in enhanced 3 D STIR sequence comparing pre-enhanced scanning,which is more suitable in displaying the details of nerve root anatomical form. So it can be used as a more ideal imaging examination method to diagnose lumbosacral nerve root disease.