轻度Alzheimer病人的弥散张量成像研究

目的研究轻度Alzheimer患者弥散张量成像的异常,并与正常老年人进行比较.方法对16例正常志愿者和14例轻度Alzheimer患者进行了弥散张量成像扫描,测量双侧杏仁核、海马头和丘脑的ADC和FA值,并对结果进行统计学比较.结果对照组和AD组的双侧海马头部的ADC值均存在显著性差异(P＜0.01),而FA值无显著性差异;对照组和AD组的双侧杏仁核的ADC值之间无显著性差异,右侧杏仁核的FA值在对照组和AD组之间存在显著性差异;双侧丘脑的ADC和FA值都没有显著性差异.结论弥散张量成像能发现轻度Alzheimer患者双侧海马头部的扩散系数的异常,从而探测到组织结构间隙的变化.     

肥厚型心肌病患者18F-FDG PET心肌代谢显像与心脏MRI

目的 评价肥厚型心肌病（HCM）患者空腹及糖负荷状态下¹⁸F-FDG PET心肌葡萄糖代谢的变化。方法 对36例HCM患者行心脏MRI（CMRI）和空腹+糖负荷状态¹⁸F-FDG PET显像,对心肌代谢显像图像进行半定量评分。根据CMRI结果将患者分为延迟强化组（n=24）及无延迟强化组（n=12）,比较2组心肌代谢评分的差异。结果 空腹状态下延迟强化组左心室心肌代谢总评分较无延迟强化组明显减低;糖负荷状态下,2组代谢总评分差异无统计学意义。11例42个心肌节段在空腹状态下放射性摄取正常或增高,而糖负荷状态下放射性摄取稀疏或缺损,与其他25例比较,其室间隔厚度、左心室后壁厚度明显增加,延迟强化心肌节段数增多,左心室射血分数明显减低,差异均有统计学意义（P均<0.05）。结论 HCM患者空腹与糖负荷状态下¹⁸F-FDG PET心肌葡萄糖代谢显像表现出不均一性,结合CMRI,有望作为HCM患者危险度分层的指标。     

慢性脑血管狭窄患者脑血流量与氧摄取分数关系的初步研究

目的 初步探讨梯度回波采样自旋回波序列(GESSE)评价慢性脑血管狭窄患者脑氧摄取分数(OEF)的价值,以及研究脑血流量(CBF)与OEF变化的相互关系.方法 选取8名正常志愿者及16例慢性单侧颈内动脉或颅内血管狭窄的患者,进行颅脑MR扫描,扫描序列包括T2WI、MRA、GESSE序列以及动脉自旋标记(ASL)序列.GESSE扫描得到的数据在Matlab软件下应用北京大学交叉学科研究院研发的后处理程序进行后处理得到OEF图,将双侧脑实质分别分为前、中、后共6个ROI,测量各个区域脑实质OEF值.ASL序列扫描数据也在该软件下进行后处理,选择与GESSE序列相同层面,并计算该层面上述ROI的CBF值,将患侧ROI的CBF与对侧对称ROI的CBF的比值定义为相对CBF(rCBF).将病变侧CBF值较对侧下降的ROI纳入研究范围.以rCBF=0.50为分割点,将所有研究范围内ROI的OEF值分为两组并采用t检验比较两者OEF值之间差异.正常志愿者的OEF值为标准,x-±2s为上下限范围,患者的OEF值与该范围进行比较.通过泊松相关分析检验rCBF与OEF的相关性.结果 8名正常志愿者平均脑组织OEF值为0.318±0.023,正常值上限为0.364,正常值下限为0.272.16例单侧血管狭窄的患者中,8例患者为单侧脑组织OEF值升高,共得到12个ROI,DSA或MRA上显示患者血管狭窄的情况为单侧多支血管狭窄或颅内主干血管多处狭窄.另外8例患者脑组织OEF值在正常范围内,共得到14个ROI,DSA或MRA上显示患者血管狭窄的情况为单支血管狭窄.以rCBF=0.50为分界点,将OEF值分为两组进行比较,rCBF≥0.50组的平均OEF值为0.325±0.028,rCBF＜0.50组的平均OEF值为0.397±0.010.两组之间的差异具有统计学意义(t=-8.840,P=0.000).相关分析发现rCBF与OEF之间存在负相关(r=-0.851,P=0.000).结论 慢性单侧颈内动脉和(或)颅内血管狭窄患者脑组织OEF值可能升高或在正常范围内,CBF值下降越明显,OEF值上升越明显.

Abstract：

Objective Using gradient-echo sampling of spin-echo (GESSE) sequence to study the change of oxygen extraction fraction (OEF) in patients with unilateral cerebral vessel stenosis and the relationship between OEF and cerebral blood flow (CBF). Methods Eight normal volunteers and 16 patients with unilateral cerebral vessel stenosis were enrolled in this study. Written informed consents were obtained from all subjects. Routine MRI, GESSE and arterial spin labeling (ASL) sequences were performed for all patients. Raw data from GESSE and VE-ASL sequences were transferred to PC to conduct postprocessing. To obtain quantitative OEF and CBF of the brain parenchyma, 6 ROIs were placed respectively in the anterior, middle and posterior part of both hemispheres. The relative CBF (rCBF) was defined as the ratio of CBF of ischemic hemisphere to that of contralateral hemisphere. T test was used for statistics. Results The mean value and normal range of OEF in the volunteers were 0. 318 ± 0. 023 and 0. 272-0. 364, respectively. In the 16 patients with unilateral cerebral vessel stenosis, 8 patients had ROIs with greater OEF in unilateral hemisphere than those in contralateral hemisphere. These cases presented multiple intracranial main arterial stenoses in digital subtraction angiography (DSA) or MR angiography (MRA) examination. The other 8 patients had normal OEF in all ROIs. And they only had single arterial stenosis in DSA or MRA. Set rCBF = 0. 50 as a dividing point, the mean OEF value was 0. 397 ±0. 010 in the patients with rCBF ＜ 0. 50. In the patients with rCBF ≥ 0. 5, the mean OEF value was 0. 325 ±0. 028. The difference between the two groups was statistically significant (t = - 8. 840, P = 0. 000).Conclusion Patients with chronic cerebral ischemia may present with various hemodynamic impairment.The more CBF decreases, the more OEF increases. Those with increased OEF tended to have more than one lesion in the major intracranial arteries.     

采用优化的基于体素的形态学方法研究智力障碍儿童脑灰质容积变化

目的 利用优化的基于体素的形态测量学(VBM)方法,比较病因不明且常规影像检查正常的智力障碍儿童与正常同龄儿童脑灰质容积的差异,探究患儿脑灰质发育与智力障碍间的联系.方法 选取21例智力障碍患儿和30名正常儿童进行高分辨率脑MR扫描,然后进行VBM分析,应用独立样本t检验比较两组儿童脑灰质容积总量以及不同区域灰质容积的差别.同时,对智力障碍儿童的智商评分与脑灰质容积总量进行偏相关性分析.结果 智障儿童脑灰质容积总量[(1.012±0.079)×106 mm3]明显大于正常儿童[(0.956±0.059)×106mm3],智障组与正常对照组儿童脑灰质总容积的差异具有统计学意义(t=-2.80,P＜0.05).智障组儿童脑局部区域灰质容积较正常对照组高,脑区包括双侧丘脑、额上回、直回和颞极,以及右侧额下回、海马旁回和右侧小脑.智障组儿童脑灰质容积与智商无相关性(r=0.078,P＞0.05).结论 VBM能够显示常规MRI表现正常的智力障碍儿童中的脑灰质发育异常.额叶-丘脑环路的脑灰质容积增加,提示其发育滞后,可能是导致儿童智力障碍的原因之一.

Abstract：

Objective To detect brain structural difference between children with unexplained mental retardation and children with typically normal development. Methods The high-resolution magnetic MR imaging were obtained from 21 children with unexplained mental retardation and 30 age-matched control children without intellectual disabilities. Voxel-based morphometry analysis with an optimization of spatial segmentation and normalization procedures were applied to compare differences of gray matter volume between the two groups. The total and regional gray matter volume were compared between the two groups with independent t test. Meanwhile, correlation was conducted to analyze the relationship between the total gray matter volume and intelligence quotient (IQ) with partial correlation test. Results The total gray matter volume was significantly increased in the mental retardation children [(1. 012 ±0. 079) × 106 mm3]in relative to the controls [(0. 956 ± 0. 059) × 106 mm3, t = - 2. 80, P ＜ 0. 05]. Compared to controls,children with unexplained mental retardation showed significantly increased gray matter volume in different regions, including the bilateral thalami, the bilateral superior frontal gyri, the bilateral gyri rectus, the bilateral temporal poles, the right inferior frontal gyrus, right parahippocampal gyrus and the right cerebellum. No correlation was detected between the total gray matter volume and IQ in children with mental retardation (r = 0. 078 ,P ＞ 0. 05). Conclusions VBM would detect the gray matter abnormalities that were not founded in routine MR scanning. The increase of gray matter volume in the frontal-thalamus network might indicate the delayed maturation of the brain development. This might be one of the causations of mental retardation in children.     

3.0T磁共振脑转移瘤IVIM与MR灌注加权成像的相关性研究

目的初步探讨利用体素内不一致运动磁共振成像(introvoxelincoherent motion MR imaging,IVIM-MRI)评价脑转移瘤的灌注,并与灌注加权成像(perfusion weighted Imaging,PWI)的指标进行相关性评价。方法收集在本院2012年6月~2012年12月间26例经手术证实的不同类型癌症发生脑转移的患者行MRI增强检查。扫描序列包括IVIM及PWI。选取颅内转移病灶共60个,应用工作站后处理软件分别测定瘤体及对侧Slow ADC(SADC)、Fast ADC(FADC)、Fraction of FastADC(FFADC)和血流量(cerebral blood flow,CBF)、血容量(cerebral blood volume,CBV),并计算出各个参数的相对值(r),即:r值=(实质病灶值/对侧正常值)×100%。将瘤体与正常侧的IVIM指标进行统计学比较,并将IVIM与PWI的各参数进行Pearson相关性分析。对IVIM和PWI的参数进行转移瘤诊断的ROC分析。结果转移瘤的SADC为(0.437±0.023)×10-3 mm2/s),其对侧脑组织的SADC为(0.223±0.010)×10-3 mm2/s),两者间差异有统计学意义(t=4.83,P0.01);转移瘤的FADC为(3.65±0.11)×10-3 mm2/s),其对侧脑组织的FADC为(2.27±0.12)×10-3 mm2/s),两者间差异有统计学意义(t=8.36,P0.05);转移瘤的FFADC为441.67×10-3±21.19×10-3,其对侧脑组织的FFADC为276.5×10-3±8.07×10-3,两者间差异有统计学意义(t=7.28,P0.01)。转移瘤的rFADC为5.57±31.66,rCBV为2.79±1.27,Person相关性分析显示rFADC与rBV呈弱相关(r=0.274,P0.05),而rFFADC、rSADC与rCBF、rCBV无明显相关性。FADC、FFADC、SADC、CBF、CBV的ROC曲线分析显示,AUCFADC=0.924(P=0.025);AUCFFADC=0.860(P=0.034);AUCSADC=0.896(P=0.030);AUCCBF=0.849(P=0.035);AUCCBV=0.865(P=0.034)。FADC的ROC曲线的AUC最大,诊断准确性更高。结论 IVIM的参数测量能反映转移瘤的灌注特性,但是由于与PWI的技术原理不同,灌注的测量指标之间只具有弱相关性。     

单体型特纳综合征患儿全脑灰、白质基于体素的形态学分析

目的 利用基于体素的形态测量学(VBM)方法,探测单体型特纳综合征(TS)患儿脑灰、白质体积的异常.方法 选取9例染色体核型为45XO的单体型TS患儿(TS组)和20名正常女童(对照组),进行了韦氏智力测量和3.0TMR扫描.TS组和对照组的全脑高分辨率T1WI采用统计参数图SPM 8软件包进行VBM分析,以全脑灰、白质总体积为协变量,以协方差分析比较单体型TS患儿和对照组之间全脑灰、白质体积的差别,采用功能神经图像分析软件包(AFNI)中的蒙特卡洛模拟方法(即AlphaSim方法)进行簇水平上的多重比较校正.结果 TS组患儿韦氏总智商值为81±13,而对照组儿童韦氏总智商值为109±16,两组儿童智商差异具有统计学意义(t=-4.70,P＜0.05).与对照组比较,单体型TS患儿右侧顶上小叶、中央后回、楔叶、楔前叶、距状皮层,左侧枕叶中下部灰质体积减小,差异有统计学意义(统计区体素数目分别为631、525、520个,t值分别为3.95、3.50、3.36,P值均＜0.05);双侧辅助运动区、额上回内侧,右侧扣带回中部,左侧颞上、中、下回,左侧额上、中、下回,左侧小脑,左侧海马、海马旁回,左侧梭状回灰质体积增加,差异有统计学意义(统计区体素数目分别为2082、974、1708、588、579个,t值分别为5.45、4.59、4.40、4.29、3.55,P值均＜0.05).白质体积比较的结果表明,单体型TS患儿左侧中央后回及顶下小叶的白质体积较对照组减小,差异具有统计学意义(体素数目957,t=5.85,P＜0.05).结论 TS患儿存在脑灰、白质发育的异常,该异常改变可能是单体型TS患儿认知功能障碍的神经病理学基础.     

Menkes病的MR影像表现

目的 探讨Menkes病的MRI特征.方法 回顾性分析2006年至2012年间9例确诊为Menkes病患儿的临床及MR影像资料.9例患儿均为男性,年龄3.5～10.0个月,中位年龄6.0个月.临床有癫痫发作、智力及运动发育落后、头发稀少及卷曲、血清铜蓝蛋白值低等表现.由2名资深的神经放射医师对其头颅MRI及MRA影像进行评价,评价内容包括颅内血管改变、脑白质异常、脑萎缩、硬膜下积液或积血等.结果 9例患儿中,8例有颅内血管迂曲样改变;8例有脑白质发育落后;1例双侧颞叶白质一过性异常及双侧额叶白质异常,2例双侧颞叶白质明显异常并累及皮层下白质,1例右侧额叶白质异常;5例患儿有大脑萎缩;7例患儿有小脑萎缩;1例为双侧顶、枕叶局限性脑萎缩;6例患儿有硬膜下积液或积血;1例患儿有双侧基底节异常.结论 Menkes病的MR表现有特征性,表现为颅内血管迂曲、脑白质发育落后、脑白质异常、硬膜下积液等,MRI及MRA检查有助于Menkes病的诊断.     

儿童急性播散性脑脊髓炎的临床与影像学表现

目的探讨急性播散性脑脊髓炎(ADEM)的临床与影像学表现特点。方法分析22例ADEM患儿的临床及影像学资料,并对ADEM的临床表现进行归类,观察ADEM患儿的脑MRI表现,包括病灶位置(皮层、皮层下白质、中央白质、脑室旁白质、深部灰质核团以及脑干和小脑)、大小、形态。结果 22例ADEM患儿的发病年龄平均(6.0±3.2)岁。前驱症状中以发热常见,占77.27%(17/22)。临床表现以脑病及抽搐最多见,各占45.45%(10/22);运动障碍次之,占36.36%(8/22)。影像学上,22例患儿中均可见中央白质病变;13例(13/22,59.09%)可见脑室旁病灶;9例(9/22,40.91%)可见皮层病灶;6例(6/22,27.27%)累及深部灰质核团。18例患儿急性期后1个月复查MRI,8例可见脑萎缩。结论儿童ADEM的MRI表现多样,可表现为中央白质病变,还可出现脑室旁病灶及灰质受累。影像学动态观察有助于了解疾病的变化。     

功能核磁共振成像法评价妇女局部应用前列腺素E1乳膏的脑局部反应

目的：通过功能性核磁共振扫描（fMRI）评价在视觉刺激条件下在阴蒂和G点涂抹前列腺素E1乳膏后的脑激活状态.方法：健康妇女及性唤起障碍妇女各5名,进行随机、双盲、安慰剂交叉对照研究.每一位受试者随机应用前列腺素E1乳膏或安慰剂乳膏,两次访视间隔7天的清洗期.通过fMRI评价脑区域的激活状态.结果：在健康组中,药物强于安慰剂的区域为左侧额上回、右侧前额叶,但是在双侧顶叶位置较弱;在患者组中药物组的激活状态在右侧顶叶较安慰剂减弱.前列腺素E1在健康组左侧前语言区、右侧岛叶、左后扣带回和右侧顶叶的激活状态高于患者;在左侧梭状回、右侧前额叶、左侧额上回患者的激活效应高于健康组.结论：前列腺素E1乳膏的作用是性刺激依赖的.右侧前额叶、左侧额上回是与药物效应有关的激活脑区,患者和健康人之间的脑部不同激活模式可能与病因有关.