健康者三叉神经磁共振扩散张量成像研究

目的 测量三叉神经桥池段的表观扩散系数(ADC)值和部分各向异性分数(FA)值，了解三叉神经桥池段各参数的特点。 方法 选择50例健康志愿者三叉神经桥池段距离脑干发出点0mm、3mm、6mm、9mm共四处，利用DTI图像与B-TFE或THRIVE图像融合成像，提高三叉神经桥池段显示的空间分辨率，并利用该图像测量并分别记录ADC值与FA值，对所有受检者行三叉神经桥池段追踪成像。 结果 受检者左侧与右侧三叉神经桥池段的ADC值和FA值差异均无统计学意义(P＞0.05)。越靠近脑干发出点，左右两侧三叉神经桥池段的各导出量越呈现左右不对称的趋势。双侧三叉神经桥池段距脑干不同距离各位置的DTI导出量分析发现：相邻两距离间ADC值差异均有统计学意义(P＜0.05)，出脑干后随距离增加ADC值逐渐升高，但行至6～9 mm间突然回转下降；FA值在0～6 mm间随距离增加而逐渐降低，且相邻两距离间差异均有统计学意义(P＜0.05)，但行至6～9 mm间FA值不再有明显变化。 结论 DTI图像能够清晰分辨双侧三叉神经桥池段，可实现DTI各项导出量的测量。随着距脑干发出点距离的不同，各导出量发生有规律的变化，预示着DTI在明确区分三叉神经的中枢神经系统段、过渡段和周围神经系统段以及检出颅神经血管压迫方面的应用前景。

Magnetic resonance diffusion tensor imaging of trigeminal nerve in healthy volunteers

Objective To survey the apparent diffusion coefficient (ADC) value and fractional anisotropy (FA) value ofpontine cistern section of the trigeminal nerve, and understand the characteristics of various parameters of trigeminal nerve pontine cistern section. Methods The distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem in 50 healthy volunteers were recorded, and fusion images of magnetic resonance diffusion tensor imaging (DTI) with B-TFE or THRIVE were achieved to improve the spatial resolution of the pontine cistern section of the trifacial nerve; their ADC value and FA value were recorded, separately. Tracing image formation was noted in the pontine cistern section of the trigeminal or trifacial nerve. Results The ADC and FA results of the left side and right flank of pontine cistern section of the trifacial nerve in these healthy volunteers were not statistically different (P＜0.05). The closer to the brain stem, the more asymmetrical tendency of distance from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem between both sides. DTI indicated that the ADC values between each 2 distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mum of brain stem between both sides were significantly different: the ADC values increased along with the distance elevating gradually, but rotated suddenly at the line of 6-9 mm. The FA value increased in 0-6 mm along with the distance reducing gradually, and the neighboring 2 distances had remarkably statistical difference, but the FA value no longer obviously changed from the line of 6-9 mm. Conclusion DTI can distinguish the two-sided trigeminal nerve brain pond section clearly, and may realize each item of DTI. Regular changes are noted in FA and ADC values along with the different distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem,indicating that DTI enjoys perspective in being clear about the discrimination of cranial nerve CNS section, the change-over portion and the PNS section, and in detecting the cranial nerve vascular compression.