血管周围间隙的MRI表现

皮质脊髓束Waller变性,周林江 杨艳梅,中央前回中、上部和中央旁小叶前部以及其他一些皮质区域锥体细胞的轴突集合组成皮质脊髓束，经内囊后肢下行，至中脑的大脑脚底，占其中间35的外侧部；然后至脑桥基底部，分散成大小不等的纤维束下行；至延髓锥体，纤维又集拢形成一束。,各神经束可随意标示为各种不同颜色,皮质脊髓束Waller变性是由于它的上运动神经元或轴突的损伤而引起其远端的轴突和髓鞘顺行性变性。,引起皮质脊髓束Wallerian变性的原因，最常见者为脑卒中（包括脑梗死和脑出血），较少见者还有脑外伤、脑肿瘤和脱髓鞘性病变等。,1,M，56y, MR-10157215, Lt hemiplegia for 8 months,1,M，56y, MR-10157215, Lt hemiplegia for 8 months,1,M，56y, MR-10157215, Lt hemiplegia for 8 months,M,32y,MR-10160518, traffic accident before 6 months, coma for 2-3d,intracranial hemorrhageRt hand weakness and Rt legs adducted in the present (hemiparesis),2,M,32yMR-10160518,2,M,32yMR-10160518,2,M,10y,MR-10137589, Lt hemiplegia for 2y, Granulomatous disease,4,5,M,42y,MR-10175627, cerebral infarction sequela, Rt hemiplegia for 7months,F,46y,MR-10172661,10 years after cerebral infarction,6,M, 50y MR-25383, 9 months after intracranial trauma, Lt upper and lower limb weakneess,7,MR-25440,8,M, 48y, MR-31384, Lt basal ganglia encephalomalacia,9,M,44y, MR-23425,MR-25219 男 34岁，进行性加重的肢体无力，肌束震颤，言语不清，吞咽困难，肌张力增高,肌电图提示广泛的神经元性异常表现Amyotrophic lateral sclerosis, ALS,MR-28898 adrenoleukodystropy,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,Pyramical tract,特点,特点,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,Journal of neurological sciences 178(2000)167-169,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,Motor cortexthe posterior limb of the internal capsulecerebral pedunclebasis pontismedullary pyramid,Pyramical tract,UMN weakness Increased tone Pyramidal-pattern weakness Absence of muscle wasting and fasciculations Brisk tendon reflexes and extensor plantar responses,Pyramical tract,Hemiparesis, hemiplegia, palsy and paresis,Acta radiol 2007(6),24-day-old cerebral infarct in the left MCAThe myelin-stained section corresponding to the postmortem T2WI of the midbrainModerate pallor in the left cerebral peduncleReveal vacuolation of myelin, mild loss of axons and scattered axonal swellings,早期髓鞘空泡化，亚急性和慢性期髓鞘和轴索的丢失和巨噬细胞浸润T2高信号在不同时期具有不同的病理特征,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,脑梗死后3个月。组织学检查示同侧皮质脊髓束轴索空泡形成，轴索和髓鞘缺失，巨噬细胞浸润,脑梗死后2年。组织学检查示同侧皮质脊髓束大量轴索和髓鞘缺失，少量巨噬细胞浸润，组织疏松。,Stage 1: first 4 weeks; axonal degradation with little biochemical change in myelin; MRI(-) Stage 2: 4-14 weeks; myelin protein breakdown but myelin lipids remain intact and tissue become hydrophobic;high lipid-to-protein ratio results in T2 hypointensity Stage 3: 14 weeks; myelin lipid breakdown,gliosis,and changes in water content and structure, and tissues become hydrophilin, resulting in high T2 signal Stage 4: several years later, and is characterized by atrophy and the persistence of high T2 signal.,Four stages of WD in the CNS,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,J. Neurol. Neurosurg. Psychiatry 2007;78:587-592.,Length of DCST affected predicts outcome.Involvement of peduncle middle third may correlate with outcome,involvement of lateral or median peduncle was not correlated to outcome.Decending corticospinal tracts (DCST) refers to caudally directed motor fiber tracts definable at levels of the posterior limb of the internal capsule,cerebral peduncle, basis pontis, and medullary pyramid.,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,M,44yMR-101650617months Cerebral hemorrhage,3,3,M,44y MR-10165061, 7 months after cerebral hemorrhage,J. Neurol. Neurosurg. Psychiatry 2007;78:587-592.,4d,90d,4d,30d,90d,90d,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,右侧大脑中动脉主干供血区脑梗死（发病第3天）,右侧基底节区脑梗死（发病后14天）,Neuroscience Letters 426 (2007) 123-127,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,NeuroImage 39(2008)1370-1382,早期检测FA：定量分析预测预后,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,NeuroImage 39(2008)1370-1382,LocationLesionTimeSymptomMR signalDTI/DWIBOLD,文献复习继发性损害secondary degeneration 切断周围神经后，其远侧段轴突所发生的顺行性变性，即waller变性（Wallerian degeneration）。 神经纤维切断后，其轴突近侧段和胞体也发生变性，叫做逆行性变性（retrograde degeneration）。中枢神经某些特定部分，神经元的变性可跨越突触引起与之接触的下一个神经元变性，这种现象称为跨神经元变性（transneuronal degeneration）或跨突触变性（transsynaptic degeneration）。除上述外，中枢神经的老年性变化、药物或放射线所造成的神经组织坏死以及某些疾病所造成的变性，也都属神经变性的范围。,男性， 18岁，头外伤后引起右侧大脑中动脉夹层，原发性基底节/皮层出血性梗死后在同侧黑质出现了迟发性T1等信号/T2高信号的改变，黑质MR改变在外伤后第26天的T2WI上明确显示，而在第5天和第39天的MR检查中黑质信号如常。,Stroke 1999;30:1975-1977,Substantia Nigra,Substantia Nigra,Magnetic Resonance in Medical Sciences 2002,1(3):175-178,SubstantiaNigra,8 days,50y,M,infarctiong in left fronto-perieto-temporal region 6w 10w 24w,Corpus callosum,thalamus,Ogawa T, Yoshida Y, Okudera T, Noguchi K, Kado H,Uemura K. Secondary thalamic degeneration after cerebral infarction in the middle cerebral artery distribution: evaluation with MR Imaging. Radiology 1997,204:255-262.,thalamus,MCAO 7d and 3m,HOD是1 种特殊的跨神经突触变性绝大多数病例继发于中脑、桥脑或小脑的出血、梗死或肿瘤性病变其结局是远隔部位的下橄榄核神经元在原发病变后的一段时期发生顺行性空泡化变性,导致下橄榄核部位体积增大，在MR 图像上表现为延髓腹外侧孤立的局限性T2WI 高信号结节灶。临床主要表现为腭肌震挛、眼肌震颤、肢体阵挛或共济失调,hypertrophic olivary degeneration , HOD肥大性下橄榄核变性,Guillain-Mollaret 三角肌阵挛三角(myoclonic triangle),环路联系着一侧红核、下橄榄核和对侧齿状核。,图14 男,36 岁。中脑左侧血管瘤手术后8 个月复查,显示中脑被盖左侧长T1 (图1) 、长T2 (图2) 软化灶。延髓左侧下橄榄核体积增大,于T2WI (图3) 上呈高信号、T1WI (图4) 上呈等信号,中华放射学杂志2003；4,hypertrophic olivary degeneration , HOD肥大性下橄榄核变性,图5 ,6 男,69 岁。高血压病左侧桥脑被盖部梗死4 个月行MR 检查,左侧桥脑被盖部有局限性T2WI 高信号梗死灶(图5) 。延髓左侧下橄榄核呈T2WI 高信号(图6),中华放射学杂志2003；4,hy