颈椎病磁共振扩散张量成像的研究

目的探讨颈椎病磁共振扩散张量成像（MRDTI）的特点。方法应用3．0TMRI仪对颈椎病患者进行M_RDTI检查,根据MRI显示的脊髓受压严重程度将颈椎病患者分为轻度组、中度组、重度组及严重度组。分析各组纤维示踪（FT）图的特征及各定量参数的变化。结果60例颈椎病患者FT显示纤维束狭窄、离断、稀疏,随着脊髓受压程度的加重而加重。FA值、Ez值、E3值、E⊥值、MD值在各组之间均存在差异（P〈0．05）。随着MRI评估的脊髓受压程度加重,E2值、E3值、E⊥值、MD值逐渐升高,FA值逐渐降低。结论MRDTI可以定量、直观显示颈椎病的脊髓受压程度。     

寰枕畸形伴发脊髓型颈椎病患者一期手术治疗的临床效果评价

目的 根据寰枕畸形伴发脊髓型颈椎病患者的不同临床特征、影像学特点采取不同手术方式组合对颈脊髓进行减压,并评价探讨其疗效和预后.方法 北京大学第三医院自2002年1月至2007年7月共收治22例寰枕畸形伴发脊髓型颈椎病患者,在了解患者首发症状及病程演变情况后,以日本矫形外科学会(JOA)评分系统对手术前后体征进行分析比较,常规行X片、CT、MRI等影像学检查.一期以不同术式组合(枕颈减压、枕大池成形3例,枕颁减压、枕大池成形和空洞穿刺引流1例,枕颈减压、单开门椎管扩大成形5例,枕颈减压、局限性单侧椎板切除减压1例,枕颈减压、钛板内固定1例,枕颈减压+颈前路间盘摘除、植骨、钛板内固定1例,枕颈减压、枕大池成形+单开门椎管扩大成形3例,枕颈减压、枕大池成形+局限性单侧椎板切除减压4例,枕颈减压、枕大池成形和空洞穿刺引流+局限性单侧椎板切除减压3例)对两种病变造成的颈脊髓等神经系统压迫进行允分减压.术后全部患者均随访调查,并以改善、稳定、进展时患者术后中期状况进行评价.结果 术后效果优6例(手术前后JOA分值差≥2),好13例(JOA分值差=1),一般3例(JOA分值差为0).随访2～48月,进一步改善20例,稳定2例.结论 根据不同临床表现、体征和影像学特点,采取不同术式组合一期手术治疗寰枕畸形伴发脊髓型颈椎病可获良好的治疗效果.     

弥散张量成像在颅内环形强化病变中的诊断价值

目的 探讨弥散张量成像(diffusion tensor imaging,DTI)对颅内环形强化病变的诊断价值.方法 53例颅内单发环形强化病例术前行DTI扫描,分别测量病变坏死区、灶周水肿区及对侧正常脑实质的平均弥散系数(MD)值及各向异性分数(FA)值.并通过弥散张量纤维束成像(diffusiontensor tracking,DTT)观察病灶与白质纤维束的关系.结果 脑脓肿坏死区的MD值为(0.60±0.13)×10-3 mm2/s,FA值为0.18±0.03,高级别星形细胞瘤MD值为(2.76±0.26)×10-3mm2/s,FA值为0.07±0.02,脑转移瘤MD为(2.82±0.29)×10-3mm2/s,FA值为0.06±0.02,前者与后两者间差异有统计学意义(P<0.01).高级别星形细胞瘤水肿区的FA值(0.23±0.06)与脑转移瘤(0.17±0.06)和脑脓肿(0.15±0.03)两者水肿区FA值差异有统计学意义(P<0.01).DTT可以较准确地反映病灶与白质纤维束的关系,为手术治疗及评估预后提供依据.结论 坏死区MD值及FA值有助于脑脓肿与环形强化脑肿瘤的鉴别;水肿区FA值有助于脑星形细胞瘤与转移瘤、脑脓肿的鉴别;DTT能够为优化手术方案及评估预后提供一定帮助.     

Significance of increased signal intensity on MRI in prognosis after surgical intervention for cervical spondylotic myelopathy

We aimed to examine whether increased signal intensity (ISI) on T2-weighted MRI can be used to predict the surgical outcome of patients with cervical spondylotic myelopathy (CSM). ISI on T2-weighted MRI are frequently observed but the relevance of this finding remains controversial in patients with CSM. Between September 2007 and February 2009, 52 patients with CSM who underwent surgery were studied prospectively. Preoperative and postoperative functional status was evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system, and the recovery rate was calculated using the Hirabayashi method. An MRI was performed on all patients. For those with ISI on T2-weighted MRI, the ratio of the signal intensity on T2-weighted to T1-weighted MRI (T2:T1 ratio) at the same spinal cord level and of similar area was calculated. Although the clinical outcome of all patients had improved at final follow-up, there was a significant difference between patients with ISI and those without ISI in age, duration of symptoms, preoperative and postoperative JOA scores, and recovery rate. The preoperative and postoperative JOA scores and the recovery rate differed significantly (p < 0.05) between the three groups: patients without a T2-weighted ISI, and those with different levels of a T2:T1 ratio. Patients with an ISI usually had a low preoperative JOA score and experienced less improvement in neurologic function after surgery. The T2:T1 ratio can be used to help predict surgical outcomes.     

弥散张量成像在颅脑损伤昏迷病人中的应用

目的初步探讨颅脑损伤昏迷病人上行网状激活系统(ARAS)弥散张量成像(DTI)和预后的相关性。方法以最近3年的颅脑损伤后昏迷病人为研究对象,在颅脑创伤后的3周和5周行DTI和纤维示踪成像(DTT)检查。种子兴趣区为中脑和桥脑被盖区,目标兴趣区为丘脑板内核。分析ARAS纤维束的部分各向异性(FA)、平均弥散率(MD)、纤维束量(TV),及其变异和病人颅脑创伤3月后意识状态的关系。采用Spearman相关分析,分析FA、MD、TV和预后评分的相关性。结果 3周时上行网状激动系统FA、MD和3月时的预后之间无相关性,TV和3月时的预后有统计学相关性(相关系数为0. 89,P 0. 001)。5周时,FA、TV和3月时的预后呈正相关性(P 0. 001),3周至5周间FA的变异与3月时的GCS评分和GOS评分呈正相关(P 0. 005,P 0. 05),TV变异和3月时GCS评分和GOS评分呈正相关(P 0. 001)。结论颅脑损伤后昏迷患者3月后的意识状态和DTI所模拟颅脑损伤后5周时ARAS的FA、MD、TV及动态变化有相关性。亚急性期上行网状激动系统纤维束的改变可以间接反映患者意识恢复能力。     

复发-缓解型多发性硬化患者丘脑扩散张量成像研究

目的 通过扩散张量成像研究复发-缓解型多发性硬化患者常规MRI表现正常的丘脑扩散参数异常,以及与临床残疾程度和认知损害间的相关性.方法 24例复发-缓解型多发性硬化患者和与之性别、年龄相匹配的健康志愿者分别接受常规MRI和扩散张量成像检查,利用兴趣区法测量影像正常的丘脑扩散参数,比较两组受试者丘脑平均扩散率和部分各向异性间的差异性,并评价患者丘脑扩散参数与临床相关评分及病灶体积之间的相关关系.结果 复发-缓解型多发性硬化组患者丘脑平均扩散率[(85.34+14.68)x10-3mm2/s]低于正常对照组[(98.42±13.10)×10-3mm2/s],组间差异具有统计学意义(t=-3.257,P=0.002);丘脑部分各向异性(0.40±0.04)高于正常对照组(0.36±0.05),差异亦有统计学意义(t=3.163,P=0.003).复发-缓解型多发性硬化组患者丘脑平均扩散率与同步听觉连续加法测验评分呈显著正相关(r= 0.711,P=0.000).结论 对常规MRI表现正常的复发-缓解型多发性硬化患者,扩散张量成像可以发现丘脑异常.而且丘脑扩散异常与患者认知损害存在相关性,提示扩散张量成像作为评价临床功能的重要指标,具有很好的应用前景.     

颈髓弥散张量成像在肌萎缩性侧索硬化诊断中的应用

目的 初步探讨颈髓弥散张量成像(DTI)在肌萎缩性侧索硬化(ALS)诊断中的应用价值. 方法 选择自2000年1月至2007年1月中山大学附属第二医院骨科收治的28例ALS患者为患者组,20例同期门诊查体健康成年人为对照组,对2组成员进行常规MRI扫描及DTI检查,获取颈髓MD值及FA值的直方图,并对ALS患者颈髓DTI弥散张量值与患者ALS残损功能评分量表(ALSFRS)评分进行相关性分析. 结果 与对照组相比,患者组颈髓FA值和颈髓横断面积明显降低,差异有统计学意义(P<0.05);MD值轻微增加,差异无统计学意义(P>0.05).患者颈髓FA值与ALSFRS评分高度相关(r=0.730,P=0.000),与MD值等指标无相关关系. 结论 ALS患者颈髓DTI显像FA值显著降低,FA值可能成为ALS诊断中的神经影像学阳性支持指标:颈髓的弥散张量值与ALSFRS结合,可以更伞面反映ALS患者的病情进展.     

人工颈椎间盘置换早期运动学分析：55例资料验证

背景：颈椎前路椎间盘切除椎间融合被认为是治疗颈椎病的金标准,但是融合后产生临近节段的加速退变。采用人工颈椎间盘置换治疗颈椎病和颈椎间盘突出症在解除患者脊髓压迫的同时保持了颈椎的活动度和稳定性,恢复椎间盘正常的生物力学特点,防止邻近椎间盘的加速退变。 目的：观察颈椎Prodisc人工颈椎椎间盘置换的临床应用效果及术后的运动学变化。 方法：选择55例69个椎间盘,其中双节段受损14例;男29例,女26例,年龄48(31~76)岁;脊髓型颈椎病32例,神经根型颈椎病9例,混合型颈椎病14例。取颈椎前横切口或斜切口入路行Prodisc人工颈椎间盘置换。于置换前、置换后3,6,12,24个月观察颈椎正侧位、过伸过屈、左右侧屈位片,JOA评分分析置换前后椎间盘功能改善情况。 结果与结论：随访55例69个椎间盘, 41例行单节段人工颈椎间盘置换, 14例行双节段人工颈椎椎间盘置换。置换后随22(56~48)个月。 置换后JOA评分显示椎体功能改善率达56%。置换后手术节段椎间盘矢状面、冠状面活动度与置换前比较差异无显著性意义(P = 0.45, 0.74),并保持了和邻近间隙同样的活动度和稳定性。说明颈椎人工椎间盘置换后保留了原来的椎间盘的活动度,患者恢复快,对邻近椎间盘的影响小。     

脑白质疏松症的磁共振扩散张量成像研究及其与急性腔隙性脑梗死的鉴别

目的 研究脑白质疏松症(LA)和急性腔隙性脑梗死(LD在磁共振扩散张量(DTI)影像学上的特点,探讨DTI对LA诊断及其与LI鉴别诊断的价值.方法 对28例LA患者、11例LI患者和20名正常老年人行DTI扫描,测量LA病灶区、形似正常(NAWM)区、LI梗死中心、健侧对应部位和对照组正常白质区的平均扩散系数(MD)、部分各项异性(FA)值.结果 LA患者病灶分别较NAWM、对照组以及LA NAWM区较对照组,MD值升高,FA值降低.各组大脑半球左右侧(除LA NAWM区侧脑室前端和后端周围MD值外)MD和FA值无显著性差异;随LA严重程度增加,MD值升高,而FA值降低;LI梗死中心较健侧对应部位和对照组MD值、FA值均较对照组降低.结论 DTI在监测脑白质病变上远比常规MRI灵敏度高,可发现早期的LA病变.LA的DTI参数变化反映了脑白质微结构改变.LA和急性LI在DTI的表现有特征性差异,显示出DTI在LA诊断及其与LI鉴别诊断的价值.     

Clinical and radiological impact of liver transplantation for brain in cirrhosis patients without hepatic encephalopathy

Objective

To elucidate the effect of liver transplantation (LT) on brain dysfunctions in cirrhotic patients who had no clinical evidence of hepatic encephalopathy (HE), we performed a prospective study of voxel-based diffusion tensor imaging (DTI) and detailed cognitive examination.

Methods

We assessed 12 consecutive patients as transplant candidates by DTI, with neurological and cognitive examinations just before and at 6 months after LT.

Results

After LT, cirrhotic patients showed significant improvement in visual reproduction, digit symbol, digit span, Stroop test, and Trail-making test scores, suggesting recovery of frontal-temporal function. As for voxel-based DTI, increased mean diffusivity (MD) and reduced fractional anisotropy (FA) values were found before LT in the frontal and temporal lobes of cirrhotic patients. After LT, the unusual FA and MD values observed in the frontal and temporal lobes preoperatively were significantly reduced.

Conclusion

End-stage cirrhotic patients without clinical evidence of HE showed increased MD and decreased FA values in both frontal and temporal lobes. These parameters improved after LT, in line with cognitive function. MD and FA values might be of value as a biomarker in end-stage cirrhotic patients for investigating brain tissue dysfunctions and evaluating the efficacy of LT.     

A meta-analysis showing that high signal intensity on T2-weighted MRI is associated with poor prognosis for patients with cervical spondylotic myelopathy

We used PubMed, Medline, and EMBASE to conduct a meta-analysis to determine the significance of high signal intensity on T2-weighted MRI for predicting postoperative prognosis in patients with cervical spondylotic myelopathy (CSM). Although patients with CSM with high signal intensity on T2-weighted MRI usually had a poor prognosis even after undergoing surgery, some researchers have argued recently that high-intensity signals are not associated with postoperative prognosis. Data consistent with the inclusion criteria of this study were cited for meta-analysis using Review Manager 5 Software. The postoperative recovery ratio specified by the Japanese Orthopedic Association (JOA) was assessed using the weighted mean difference (WMD) method. Five articles (one prospective; four retrospective) involving 309 patients with CSM were included. The aggregate WMD with regard to the postoperative JOA recovery ratio between the T2-weighted high signal intensity positive (+) group and the T2-weighted high signal intensity negative (-) group was -6.56, and the 95% confidence interval (CI) was -12.15 to -0.97 (p=0.02). Thus, we concluded that in patients with CSM, the postoperative JOA recovery ratio in the T2-weighted (+) group was lower than that in the T2-weighted (-) group.     

Prediction of outcome following laminoplasty of cervical spondylotic myelopathy: Focus on the minimum clinically important difference

The minimum clinically important difference (MCID) of the Japanese Orthopaedic Association (JOA) score has been reported to be around 2.5 points in cervical myelopathy. This study sought to define significant predictive factors on achieving the MCID following laminoplasty in a large series of patients with cervical spondylotic myelopathy (CSM). A total of 485 consecutive patients with CSM (295 males and 190 females; mean age: 67.0 years; age range: 42–91 years) who underwent laminoplasty were prospectively enrolled. The average postoperative follow-up period was 26.6 months (range: 12–66 months). We calculated the achieved JOA score. The relationships between outcomes and various clinical and imaging predictors including comorbidity and quantitative performance tests were examined. Logistic regression analysis was conducted to identify the predictors correlated with a JOA score of 2.5 points or more. Clinically meaningful gains were exhibited in 299 patients (61.6%) with a JOA score of ≥2.5 points, whereas 186 patients (38.4%) achieved a JOA score of <2.5 points. Univariate logistic regression analysis showed the predictive factors with a shorter duration of CSM symptoms, lower preoperative JOA scores, absence of hypertension, no use of anticoagulant/antiplatelet agents, and nonsmoking status. Multivariate logistic regression analysis determined that the duration of CSM symptoms (odds ratio: 0.771, 95% confidence interval: 0.705–0.844; p < 0.01) was the only significant predictive factor for achieving JOA scores of ≥2.5 points. An important predictor of MCID achievement following laminoplasty was shorter duration of CSM symptoms.     

Successful Motor Evoked Potential Monitoring in Cervical Myelopathy : Related Factors and the Effect of Increased Stimulation Intensity

ObjectiveIntraoperative neurophysiological monitoring (IONM) has been widely used during spine surgery to reduce or prevent neurologic deficits, however, its application to the surgical management for cervical myelopathy remains controversial. This study aimed to assess the success rate of IONM in patients with cervical myelopathy and to investigate the factors associated with successful baseline monitoring and the effect of increasing the stimulation intensity by focusing on motor evoked potentials (MEPs). MethodsThe data of 88 patients who underwent surgery for cervical myelopathy with IONM between January 2016 and June 2018 were retrospectively reviewed. The success rate of baseline MEP monitoring at the initial stimulation of 400 V was investigated. In unmonitorable cases, the stimulation intensity was increased to 999 V, and the success rate final MEP monitoring was reinvestigated. In addition, factors related to the success rate of baseline MEP monitoring were investigated using independent t-test, Wilcoxon rank-sum test, chi-squared test, and Fisher’s exact probability test for statistical analysis. The factors included age, sex, body mass index, diabetes mellitus, smoking history, symptom duration, Torg-Pavlov ratio, space available for the cord (SAC), cord compression ratio (CCR), intramedullary increased signal intensity (SI) on magnetic resonance imaging, SI length, SI ratio, the Medical Research Council (MRC) grade, the preoperative modified Nurick grade and Japanese Orthopedic Association (JOA) score. ResultsThe overall success rate for reliable MEP response was 52.3% after increasing the stimulation intensity. No complications were observed to be associated with increased intensity. The factors related to the success rate of final MEP monitoring were found to be SAC (p<0.001), CCR (p<0.001), MRC grade (p<0.001), preoperative modified Nurick grade (p<0.001), and JOA score (p<0.001). The cut-off score for successful MEP monitoring was 5.67 mm for SAC, 47.33% for the CCR, 3 points for MRC grade, 2 points for the modified Nurick grade, and 12 points for the JOA score. ConclusionIncreasing the stimulation intensity could significantly improve the success rate of baseline MEP monitoring for unmonitorable cases at the initial stimulation in cervical myelopathy. In particular, the SAC, CCR, MRC grade, preoperative Nurick grade and JOA score may be considered as the more important related factors associated with the success rate of MEP monitoring. Therefore, the degree of preoperative neurological functional deficits and the presence of spinal cord compression on imaging could be used as new detailed criteria for the application of IONM in patients with cervical myelopathy.     

The use of evoked potentials for clinical correlation and surgical outcome in cervical spondylotic myelopathy with intramedullary high signal intensity on MRI

OBJECTIVE: To investigate the use of motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) for clinical significance and surgical outcome in patients with cervical spondylotic myelopathy (CSM) with intramedullary high signal intensity on T2 weighted MRI. METHODS: Forty nine patients were scored according to the modified Japanese Orthopaedic Association (JOA) score for cervical myelopathy. MEP and SEP studies were performed and the results were categorised as normal or abnormal. Thirty nine patients who had received surgical decompression were re-evaluated after 6 months. Surgical outcome was represented by the recovery ratio of the JOA score. RESULTS: Abnormal MEPs were observed in 44 patients (arm: 43; leg: 30). Abnormal SEPs were found in 32 patients: (median: 24; tibial: 23). Patients with abnormal SEPs had a worse JOA score than those with normal SEPs. Thirty nine patients received surgical treatment. Patients younger than 55 had better recovery ratios than those who were 55 or older (p = 0.005, two sample Student's t test). Patients with normal median SEPs also had better recovery ratios than those with abnormal median SEPs (p = 0.007, two sample Student's t test). Among median SEP variables, only N9-20 was significantly associated with recovery ratio (p = 0.016, stepwise linear regression), with age factor controlled (p = 0.025, stepwise linear regression). CONCLUSION: Arm MEP was the most sensitive EP test for detecting myelopathy in patients with chronic CSM. Median and tibial SEPs correlated well with the severity of myelopathy while normal median SEPs correlated with good surgical outcome. Among median SEP variables, only N9-20 correlated with surgical outcome.     

Thoracic Myelopathy Caused by Ossification of the Ligamentum Flavum

Objective

Ossification of the ligamentum flavum (OLF) is a rare cause of thoracic myelopathy. The aim of this study was to identify factors associated with the surgical outcome on the basis of preoperative clinical and radiological findings.

Methods

Data obtained in 26 patients whot underwent posterior decompression for thoracic myelopathy, caused by thoracic OLF, were analyzed retrospectively. Patient age, duration of symptoms, OLF type, preoperative and postoperative neurological status using the Japanese Orthopedic Association (JOA) scoring system, surgical outcome, and other factors were reviewed. We compared the various factors and postoperative prognosis. All patients had undergone decompressive laminectomy and excision of the OLF.

Results

Using the JOA score, the functional improvement was excellent in 8 patients, good in 14, fair in 2, and unchanged in 2. A mean preoperative JOA score of 6.65 improved to 8.17 after an average of 27.3 months. According to our analysis, age, gender, duration of symptoms, the involved spinal level, coexisting spinal disorders, associated trauma, intramedullary signal change, and dural adhesions were not related to the surgical outcome. However, the preoperative JOA score and type of OLF were the most important predictors of the surgical outcome.

Conclusion

Early diagnosis and sufficient surgical decompression could improve the functional prognosis for thoracic OLF. The postoperative results were found to be significantly associated with the preoperative severity of myelopathy and type of OLF.     

皮质下缺血性血管病患者联络纤维的扩散张量成像分析和认知功能相关研究

【摘要】 目的 运用磁共振成像（magnetic resonance imaging,MRI）基于白质地图的扩散张量成像（diffusion tensor imaging,DTI）技术研究皮质下缺血性血管病（subcortical ischemic vascular disease,SIVD）患者联络纤维的超微结构改变,并分析DTI参数与认知功能的关系。 方法 连续入选40例SIVD患者,分为血管性认知障碍组18例,无认知障碍组22例,另设立20例正常老年人为对照组。对三组进行MRI检查并对其白质改变进行评分,对联络纤维进行基于白质地图分析（atlase based analysis,ABA）DTI成像,比较组间部分各向异性指数（fractional anisotrophy,FA）、平均扩散率（mean diffusivity,MD）差异,并对SIVD患者DTI参数与蒙特利尔认知评估量表（Montreal Cognitive Assessment,MoCA）得分进行相关性分析。 结果 无认知障碍组较正常组在右侧矢状层（下纵束/下额枕束）、右侧扣带（海马部）及左侧上额枕束的FA值减低;认知障碍组较正常组存在广泛的联络纤维FA值降低,差异均具有显著性。无认知障碍组与正常组比较,仅左侧扣带海马部及左侧上纵束MD值无显著差异,余联络纤维的MD值均显著增高;认知障碍组较正常组存在广泛的联络纤维MD值增高,差异均具有显著性。与无认知功能障碍组比较,认知功能障碍组在双侧矢状层（下纵束/下额枕束）、双侧扣带扣带回部、海马部、双侧上纵束、双侧上额枕束及双侧钩束的FA值减低,MD值增高,差异具有显著性。SIVD患者双侧矢状层（下纵束/下额枕束）、扣带扣带回部、上纵束、上额枕束及钩束和左侧扣带海马部的FA值与MoCA评分呈正相关,MD值与MoCA评分呈负相关。 结论 SIVD患者联络纤维的FA值减低,MD值增高,且DTI参数与其认知功能密切相关。     

Bryan人工颈椎间盘置换治疗脊髓型颈椎病8例

回顾性分析2007-05/2008-07南通大学第二附属医院脊柱外科和上海长征医院骨科收治的脊髓型颈椎病患者8例,男2例,女6例;年龄36~58岁,病程8~24个月;病变节段：均为单节段,C4~5 5例,C5~6 3例。全部患者均采用Bryan人工颈椎间盘置换,置换后3个月行JOA评分,摄置换节段前屈后伸位、左右侧屈位X射线平片,观察假体置入后的稳定性及置换颈椎节段的活动度。结果显示置换过程中和置换后未出现神经和血管损伤的并发症,平均置换时间135 min。8例患者均进行门诊随访,随访时间3~13个月,所有患者置换后症状明显缓解。JOA评分由置换前平均8.9分(6~12分)增加到置换后第3个月平均15.2分(12~17分)。置换后3个月置换节段前屈后伸活动范围平均5.3°(4.3°~6.1°);左右侧屈活动范围分别为平均3.4°(2.8°~4.3°)和3.5°(2.9°~4.3°)。假体无偏移或下沉。末次随访未发现置换节段异位骨化、假体松动、下沉或颈椎生理曲度的改变。提示Bryan人工椎间盘置换治疗脊髓型颈椎病近期临床效果良好,能维持颈椎正常的活动范围和生理曲度。     

White matter measures are near normal in controlled HIV infection except in those with cognitive impairment and longer HIV duration

The objective of the current study was to quantify the degree of white matter (WM) abnormalities in chronic and virally suppressed HIV-infected (HIV+) persons while carefully taking into account demographic and disease factors. Diffusion tensor imaging (DTI) was conducted in 40 HIV? and 82 HIV+ men with comparable demographics and life style factors. The HIV+ sample was clinically stable with successful viral control. Diffusion was measured across 32 non-colinear directions with a b-value of 1000 s/mm²; fractional anisotropy (FA) and mean diffusivity (MD) maps were quantified with Itrack IDL. Using the ENIGMA DTI protocol, FA and MD values were extracted for each participant and in 11 skeleton regions of interest (SROI) from standard labels in the JHU ICBM-81 atlas covering major striato-frontal and parietal tracks. We found no major differences in FA and MD values across the 11 SROI between study groups. Within the HIV+ sample, we found that a higher CNS penetrating antiretroviral treatment, higher current CD4+ T cell count, and immune recovery from the nadir CD4+ T cell count were associated with increased FA and decreased MD (p < 0.05–0.006), while HIV duration, symptomatic, and asymptomatic cognitive impairment were associated with decreased FA and increased MD (p < 0.01–0.004). Stability of HIV treatment and antiretroviral CNS penetration efficiency in addition to current and historical immune recovery were related to higher FA and lower MD (p = 0.04–p < 0.01). In conclusion, WM DTI measures are near normal except for patients with neurocognitive impairment and longer HIV disease duration.     

Multilevel subtotal corpectomy and interbody fusion using a fibular bone graft for cervical myelopathy due to ossification of the posterior longitudinal ligament.

A retrospective study of the outcomes of multilevel anterior decompression and interbody fusion for cervical myelopathy due to ossification of the posterior longitudinal ligament (OPLL) was performed to both investigate the long-term results and assess the cause of late deterioration. Twenty-seven patients (mean age, 58.1 years) underwent this procedure and were followed for at least 5 years. The severity of the clinical symptoms was described using the scoring system for cervical myelopathy proposed by the Japanese Orthopaedic Association (JOA score). The average preoperative JOA score was 7.7, and the score at final follow-up was 13.4 with a recovery rate of 62.0%. A delayed deterioration was attributed to a thoracolumbar lesion other than a compromising alteration of the cervical spine. Consequently, this method of treatment for OPLL could stop the progress of ossification and keep a physiological cervical alignment and thus provide good long-term results.     

Diffusion tensor imaging for preoperative evaluation of tumor grade in gliomas

The relationship between water diffusion parameters measured using diffusion tensor imaging (DTI) and histological malignancy of gliomas was investigated. DTI was performed using a 3.0T MR scanner in 41 consecutive patients with histologically proven gliomas. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated and compared with the WHO classification of the gliomas. The FA values of grade 1 gliomas (0.150 +/- 0.017) were significantly lower than those of grade 3 (0.23 +/- 0.033) or grade 4 gliomas (0.229 +/- 0.033) (P < 0.0001, respectively). The FA values of grade 2 gliomas (0.159 +/- 0.018) were significantly lower than those of grade 3 or grade 4 gliomas (P = 0.0002, P < 0.0001, respectively). The FA threshold between low grade and high grade gliomas was 0.188. The MD values of grade 1 gliomas (1619.1 +/- 157.4 x 10(-6) mm2/s) were significantly higher than those of grade 3 (1084.5 +/- 218.9 x 10(-6) mm2/s) (P = 0.0036) or grade 4 gliomas (1098.0 +/- 291.6 x 10(-6) mm2/s) (P = 0.0002). The MD values were not correlated with the other grades of glioma. FA values can distinguish between high grade and low grade gliomas. This is useful in deciding the surgical strategy or selecting the site of stereotactic biopsy.