视神经炎多焦视觉诱发电位的初步研究

目的：研究视神经炎在多焦视觉诱发电位（ mfVEP）检查中按照不同离心度分布的各同心环的波形特征;追踪视神经炎发病后局部视神经损害情况及经治疗后的恢复情况,从而为视神经炎的诊断、疗效判定及预后监测提供客观依据。方法对30例（30只眼）单眼患轴性球后视神经炎患者进行多焦视觉诱发电位（mfVEP）和视野检测,采用同一个体的患眼治疗前后与健侧眼及15例（30只眼）正常对照组的比较方法,主要分析多焦视觉诱发电位（ mfVEP）的特征,按不同离心度的同心环进行分析,并与视野检测进行比较。结果患眼治疗前与对侧健眼比较：病变受累区域P波潜伏时相对对侧健眼对应区域延迟,振幅下降（ P＜0．05）。患眼治疗前后对比：患眼病变受累区域P波潜伏时有不同程度的改善,有统计学意义（P＜0．05）,振幅治疗前后有明显差异（P＜0．05）,治疗后均恢复正常。治疗后患眼与对侧健眼比较：P波振幅无明显差异（P＞0．05）;而潜伏时却仍有明显差异（ P＜0．05）,有统计学意义。患眼视野平均敏感度和平均缺损度已接近健侧眼。结论多焦视觉诱发电位（ mfVEP）可用于视神经炎的诊断及疗效判定,其在评价局部视神经损伤、追踪视神经损伤恢复情况较视野和传统VEP有明显的优势。     

炎性脱髓鞘性假瘤的MRI及MRS表现

目的 :分析炎性脱髓鞘性假瘤的MRI表现,探讨MRI及MRS对该病的诊断价值。方法:回顾性分析8例经手术病理证实及4例经临床证实的脑炎性脱髓鞘性假瘤的MRI平扫、增强扫描及MRS资料。结果:MRI平扫显示9例病变均表现为局灶性占位;7例呈均匀长T1信号,5例呈不均匀长T1、长T2信号。12例均静脉注射Gd-DTPA,增强扫描示病灶均明显不均匀显著强化,可呈开环状或闭环状强化。结论:脑炎性脱髓鞘性假瘤的MRI及MRS表现有一定特征且临床表现不支持占位性病变时,应考虑此病的可能性,必要时可先行激素冲击治疗,以避免手术或放射治疗造成的严重损伤。     

SD大鼠视神经不同程度损伤的闪光视觉诱发电位动态监测

目的　探索大鼠视神经不同程度损伤后闪光视觉诱发电位 (F VEP)的变化特征 ,为进一步研究间接性视神经损伤的修复提供实验基础和依据。方法　利用压力恒定的反向镊分别夹持大鼠视神经 6、30、6 0s,建立轻、中、重度视神经不完全损伤模型 ,记录正常及损伤后F VEP潜伏期和振幅的变化。结果　正常大鼠F VEP波形稳定 ,主波潜伏期 (L5b)为 5 3 6 7± 3 12ms,振幅 (A5 )为 17 83±5 91μV。视神经损伤后的大鼠F VEP与正常大鼠比较差异有统计学意义 (P <0 0 1)。损伤程度不同 ,F VEP的改变不同 ,损伤程度越重 ,伤后时间越长 ,潜伏期延迟越显著 ,波幅降低程度越大 ,F VEP的熄灭越早。结论　大鼠视神经损伤后F VEP的变化规律与神经的损伤程度一致 ,F VEP是客观反映其视神经功能的一项可靠指标     

非创伤性视神经管病变的CT、MRI表现

目的:探讨非创伤性视神经管病变的CT、MRI表现。方法:回顾性分析21例非创伤性视神经管病变的CT、MRI表现。结果:非创伤性神经管病变可引起视神经管狭窄、扩大和视神经管骨质吸收、破坏,其中引起视神经管狭窄的病变有:骨纤维异常增殖症(12例)、骨瘤(1例)、石骨症(2例)、脑膜瘤(2例);引起视神经管扩大的病变有血管畸形(1例);引起视神经管骨质吸收、破坏的病变有转移瘤(3例)。结论:CT、MRI检查对非创伤性视神经管病变引起视神经管改变的诊断起着重要作用。     

脑瘤样炎性脱髓鞘病的MRI特征

目的:总结脑瘤样炎性脱髓鞘病(tumor-like inflammatory demyelinating diseases,TIDD)的MRI特征。方法:回顾性分析11例经病理或治疗证实的脑TIDD的MRI征象。结果:11例中,9例为单发团块状,2例为多发团块或结节状。病灶位于额叶4个,颞叶2个,顶叶1个,基底节1个,桥臂1个,跨额颞叶4个。MRI平扫均呈长T1、长T2信号。MRI增强扫描:7个呈斑片状或结节样明显强化,4个明显强化、呈"开环征",2个呈片状或线状轻度强化。4个内缘显示扩张血管影,垂直于侧脑室壁。DWI表现:8个呈明显高信号,4个呈稍高或高低混杂信号,1个呈等及稍低信号。结论:脑TIDD具有特征性的MRI表现,MRI对该病的诊断、鉴别诊断有重要价值。     

乳腺肿块动态增强及高分辨MRI表现与病理相关性研究

目的:探讨动态增强和高分辨MRI中乳腺良、恶性病灶的形态学及血液动力学特点,并与病理结果对照,研究其相关性。方法:31例女性患者,年龄21~66岁,平均44.6岁。所有病例均行动态增强和高分辨MRI扫描,用高压注射器,注射速率2.5ml/s。评价病灶增强图像形态学特点,并进行血流动力学分析。结果:31例患者MRI共发现51个病灶。其中恶性12例20个病灶,良性19例31个病灶。以形态不规则、毛刺征、环形强化作为诊断乳腺癌标准,敏感性分别为60%、70%、80%,特异性83.9%、100%、93.5%,准确率74.5%、88.2%、88.2%。纤维腺瘤或纤维腺瘤样增生特征性表现有分叶状、压脂T2WI及增强后低信号分隔,敏感性分别为68%、60%、72%,特异性分别为92.3%、92%、96.2%,准确率80.4%、76.5%、84.3%。早期增强率和时间信号百分比曲线类型分布在良恶性病灶之间的差异有显著性意义(P<0.05)。以Ⅱ型、Ⅲ型曲线作为诊断乳腺癌的标准,敏感性90%,特异性86.6%,诊断准确率88%。结论:乳腺癌的特征性表现有形态不规则、环形强化和毛刺征。纤维腺瘤特征性表现有分叶状、T2WI及强化后可见低信号间隔。动态增强扫描中乳腺病变的时间-信号强度百分比曲线对鉴别良、恶性病变有较大意义,但是部分良、恶性病灶的曲线有重叠表现。     

颅内脱髓鞘假瘤的MRI表现

目的：探讨颅内脱髓鞘假瘤(DPTs)的 MRI 影像表现。方法回顾性分析10例经临床最终诊断为 DPTs 的 MRI 影像资料,所有患者均行 MRI 平扫,其中9例行增强扫描,7例行扩散加权成像(DWI),2例行单体素短回波1 H-MRS。结果其中8例患者病灶周围伴有轻~中度水肿,5例表现为多发病灶,3例表现为单发结节灶,2例表现为单发片状病灶。增强扫描中4例为开环形强化,3例为环形强化,1例结节状强化,1例斑片状强化。病灶在 DWI 上均表现为高信号,1 H-MRS 示2例均有 NAA 峰不同程度降低,Cho 峰、Lac 和 Lip 峰升高,1例谷氨酸/谷氨酰胺复合物(Glx 峰)明显升高。结论DPTs 在 MRI 影像上有一定特点,特征性表现为开环形强化,结合 DWI 及1 H-MRS 技术有助于 DPTs 和其他病变鉴别。     

单发急性炎性脑脱髓鞘疾病的MRI及MRS诊断

目的 探讨单发急性炎性脑脱髓鞘疾病(MAID)的影像学征象.方法 搜集近年来本院经临床确诊的12 例MAID病例的影像学资料,回顾分析其中枢神经系统的影像学征象.结果 12例病变的MRI表现为脑白质(11例)或基底节区(1例)体积较大的T1WI低信号,T2WI高信号,FLIAR为低信号,周边为高信号;DWI病变中心为低信号,周边呈高信号;强化扫描病变呈不规则开环状强化,环开口指向基底节区或皮层灰质,病变占位效应不明显.MRS检查中所有病例的NAA峰减低,其中6例Cr峰明显减低,所有病例均可见Cho峰明显增加,NAA/Cr比值降低,Cho/Cr比值增加,4例mI峰增加,2例出现MP峰增高及异常高大的Lac峰.经临床治疗后随访复查可见病变范围明显缩小,环状强化消失,病变NAA峰明显恢复,Cho峰明显降低.结论 MAID的影像学表现及其临床过程具有一定的特征性.     

肱骨外上髁炎及其并发症的MRI表现和相关性研究

目的:运用高分辨率MRI探索肱骨外上髁炎除伸肌总腱(CET)损伤外是否还合并其他改变,以及两者间是否存在一定的相关性.方法:23例肱骨外上髁炎患者的MRI图像由两位放射诊断医师进行分析评价,其评价内容包括CET损伤程度及合并的其他损伤,两位评价结果不一致时,经协商达成一致意见.将CET损伤程度和合并的其他损伤行Spearman等级相关分析,P＜0.05认为有显著相关.结果:23例患者共24个患病肘关节,24个肘关节肌腱均有不同程度的损伤(轻度损伤10个,中度7个,重度7个).其他并发症主要包括:桡侧尺副韧带(LUCL)损伤22个,伸肌损伤7个,骨质损伤6个,关节腔积液6个.CET和LUCL的损伤程度呈正相关(r=0.877,P＜0.01).结论:除CET损伤外,肱骨外上髁炎还合并其他改变,其中LUCL损伤最常见,并且与CET损伤呈正相关.     

急性播散性脑脊髓炎的MRI表现与临床分析

目的 :探讨急性播散性脑脊髓炎 (ADEM)脑部MRI及临床表现、病程、预后间的关系。方法 :回顾性分析 43例的MRI表现及临床资料 ,按病灶大小、数目分组 ,分析病灶大小、数目与临床表现、病程及预后间的关系。结果 :双侧脑室周围及额、颞、顶、枕白质区见多发、不对称长T1长T2 信号灶 ,部分T1WI为等信号。 18例见环形强化 ,3例轻度至中度占位效应。病灶大小与临床分级组间差异有显著性意义 (P <0 .0 5 ) ;病灶大小与病程、预后无明显相关性 ;病灶数目与临床分级、病程均无明显相关性。结论 :综合分析ADEM的脑部MRI表现 ,可在一定程度上为临床诊断、病情评估、治疗监测及评估预后提供依据。     

The optic nerve sheath on MRI in acute optic neuritis

Optic nerve sheath dilatation or gadolinium-enhancement on magnetic resonance imaging in acute optic neuritis have been previously reported but have been thought to be rare occurrences. This study recruited 33 patients with acute unilateral optic neuritis. All had their optic nerves imaged with fat-saturated fast spin-echo (FSE) imaging, and 28 had imaging before and after triple-dose gadolinium-enhanced fat-saturated T₁-weighted imaging. Follow-up imaging was performed on 20 patients (15 following gadolinium). A dilated subarachnoid space at the anterior end of the symptomatic optic nerve on FSE imaging was seen in 15/33 cases. In three of these cases, dilatation was visible on short-term follow-up. Optic nerve sheath enhancement was seen in 21/28 cases acutely: seven at the anterior end of the lesion only, five at the posterior end only and nine at both ends. Optic sheath enhancement was seen in 13 patients on follow-up. This study suggests that optic nerve sheath dilatation on FSE images and optic nerve sheath enhancement on triple-dose gadolinium-enhanced images are common findings in acute optic neuritis. Optic nerve sheath dilatation may be due to inflammation of the optic nerve, with its associated swelling, interrupting the communication between the subarachnoid space of the diseased optic nerve and the chiasmal cistern. Optic nerve sheath enhancement suggests that meningeal inflammation occurs in optic neuritis, in agreement with pathological studies of both optic neuritis and multiple sclerosis.     

Long echo time STIR sequence MRI of optic nerves in optic neuritis

MRI of the optic nerves was obtained in 13 patients with acute optic neuritis and 13 with a previous optic neuritis (ON), assessed by clinical features, visual fields and visual evoked potentials. Results of the conventional short tau inversion recovery (STIR) sequence obtained with a short echo time (STE-STIR; 22 ms) were compared with those of a long echo time (LTE-STIR: 80 ms) sequence. The conventional STE-STIR sequence revealed lesions in the optic nerves in 78.5% of acute and 58.8% of previous ON. The LTE-STIR sequence showed abnormalities in 92.8% of acutely symptomatic nerves and 94.1% of nerves with previous ON. The optic nerve lesions appeared significantly longer with the LTE-STIR sequence than with the conventional STE-STIR sequences, in both acute and previous ON.     

Detection of optic nerve lesions in optic neuritis using frequency-selective fat-saturation sequences

Summary MRI was performed on seven patients with acute optic neuritis, using two sequences which suppress the signal from orbital fat: frequency-selective fat-saturation and inversion recovery with a short inversion time. Lesions were seen on both sequences in all the symptomatic optic nerves studied.     

Detection of optic nerve atrophy following a single episode of unilateral optic neuritis by MRI using a fat-saturated short-echo fast FLAIR sequence

We describe an MRI technique for quantifying optic nerve atrophy resulting from a single episode of unilateral optic neuritis. We imaged 17 patients, with a median time since onset of optic neuritis of 21 months (range 3-81 months), using a coronal-oblique fat-saturated short-echo fast fluid-attenuated inversion-recovery (sTE fFLAIR) sequence. The mean cross-sectional area of the intraorbital portion of the optic nerves was calculated by a blinded observer from five consecutive 3 mm slices from the orbital apex forwards using a semiautomated contouring technique and compared with data from 16 controls. The mean optic nerve area was 11.2 mm2 in the affected eye of the patients, 12.9 mm2 in the contralateral eye (P = 0.006 compared to the affected eye) and 12.8 mm2 in controls (P = 0.03 compared to the affected eyes). There was a significant negative correlation between disease duration and the size of the affected optic nerve (r = -0.59, P = 0.012). The measurement coefficient of variation was 4.8%. The sTE fFLAIR sequence enables measurement of optic nerve area with sufficient reproducibility to show optic nerve atrophy following a single episode of unilateral optic neuritis. The correlation of increasing optic nerve atrophy with disease duration would be consistent with ongoing axonal loss in a persistently demyelinated lesion, or Wallerian degeneration following axonal damage during the acute inflammatory phase.     

MRI of optic nerve and postchiasmal visual pathways and visual evoked potentials in secondary progressive multiple sclerosis

We studied the relationship between abnormalities shown by MRI and functional disturbances in the visual pathway as assessed by the visual evoked potential (VEP) in 25 patients with established multiple sclerosis (MS); only 4 of whom had a history of acute optic neuritis. Optic nerve MRI was abnormal in 19 (76 %) and is thus useful in detecting subclinical disease. Optic nerve total lesion length and area on the STIR sequence was found to correlate significantly with prolongation of the VEP latency. This may reflect a predominantly demyelinating rather than inflammatory origin for the signal change in the optic nerve. Received: 21 July 1997 Accepted: 1 April 1998     

Lesion discrimination in optic neuritis using high-resolution fat-suppressed fast spin-echo MRI

Fast spin-echo (FSE) is a new sequence with acquisition times currently down to one-sixteenth of those obtained with conventional spin-echo sequences, which allows high-resolution (512×512 matrix) images to be acquired in an acceptable time. We compared the higher resolution of FSE with the medium resolution of a short inversion-time inversion-recovery (STIR) sequence in depicting the optic nerves of healthy controls and patients with optic neuritis. Optic nerve MRI examinations were performed in 18 patients with optic neuritis and 10 normal controls. Two sequences were obtained coronally: fat-suppressed FSE (FSE TR 3250 ms/TEef 68 ms, echo-train length 16, 4 excitations, 24 cm rectangular field of view, 3 mm interleaved contiguous slices, in-plane resolution 0.5×0.5 mm) and STIR (TR 2000 ms/TE 50 ms/TI 175 ms, inplane resolution 0.8×0.8 mm, slice thickness 5 mm). FSE demonstrated much more anatomical detail than STIR, e. g. distinction of optic nerve and sheath. Lesions were seen in 20 of 21 symptomatic nerves using FSE and in 18 of 21 using STIR. Nerve swelling or partial cross-sectional lesions of the optic nerve were each seen only on FSE in 3 cases. Fatsuppressed FSE imaging of the optic nerve improves anatomical definition and increases lesion detection in optic neuritis.     

Normal-appearing white matter in optic neuritis and multiple sclerosis: a comparative proton spectroscopy study

We investigated neurochemical abnormalities in the normal-appearing white matter (NAWM) on MRI of patients with optic neuritis (ON) and compared them to those of patients with multiple sclerosis (MS). Patients with ON (42) were classified into three groups according to abnormalities on brain MRI. Patients with MS (55) were devided in two groups: relapsing remitting MS (RRMS) and secondary progressive MS (SPMS). All patients underwent MRI of the brain and localised proton magnetic resonance spectroscopy (MRS) of NAWM. The results were compared to those of 15 controls. Patients with MS had significant abnormalities compared with controls and with patients with ON. Patients with RRMS and those with ON had comparable MRS parameters, while patients with SPMS had significant spectroscopic abnormalities in comparison with controls, but also with patients with RRMS. These changes consisted of a decrease in N -acetylaspartate, a neuronal marker, which may reflect axonal dysfunction and/or loss. MRS abnormalities were detected in 14 patients with ON (27 %). The main abnormalities consisted of a decrease in N -acetylaspartate, an increase in choline-containing compounds at long echo times, and the presence of free lipid peaks at short echo times. MRS of the NAWM on MRI may prove useful for detecting neurochemical brain abnormalities in ON not visible on MRI. Received: 19 January 1999 Accepted: 23 March 1999     

颅脑外伤后视神经蛛网膜下腔扩张与颅内压增高的MRI相关性研究

目的:探讨颅脑外伤患者眶内段视神经蛛网膜下腔扩张与颅内压增高的关系。方法:14例颅脑外伤并颅内压增高及蛛网膜下腔出血患者,在伤后2d内进行MRI检查,并在斜冠状位重T2加权图像上测量视神经球后4mm、10mm、16mm处蛛网膜下腔的外径,MRI检查结束后4h内进行腰穿,在施放脑脊液前测量脑脊液压力。经保守治疗6～14d,临床症状明显好转后,再重复一次MRI检查及腰穿脑脊液压力测定,对所得数据进行统计分析。结果:14例颅脑外伤并急性颅内压增高患者,首次检查脑脊液压力为2.31±0.24kPa,视神经眶内段前、中、后各测量点蛛网膜下腔的外径(左右侧平均值)分别为6.5±0.5mm、5.5±0.5mm、4.9±0.5mm,由前向后逐渐变窄(P<0.01)。经保守治疗好转后,脑脊液压力降低为1.75±0.21kPa,此时各测量点蛛网膜下腔外径分别为4.2±1.0mm、3.6±0.9mm、3.2±0.7mm,较首次检查明显变窄(P<0.01)。前、中、后各测量点的蛛网膜下腔的外径与脑脊液压力的相关系数分别为0.864、0.858、0.837(P<0.01)。结论:眶内段视神经蛛网膜下腔扩张程度与颅内压呈显著的正相关关系,可作为临床评价颅脑损伤患者颅内压增高程度的定量指标。