弥散加权成像联合磁共振波谱分析在脑梗死中的应用研究

目的探讨脑梗死弥散加权成像（DWI）和磁共振波谱分析（MRS）的特点和影响因素,及二者对评估脑梗死的临床价值。方法采用Philips Achieva 1.5T双梯度超导磁共振扫描仪,对72例临床疑是脑梗死患者行常规T1WI、T2WI、FLAIR、DWI、MRS检查,在工作站上测定梗死核心区、内缘区、外缘区、周围区和镜像区的ADC值和代谢物Lac、NAA、Cr、Cho、NAA/Cr、Lac/Cr、Lac/NAA值。结果 DWI显示的梗死灶范围较常规MRI像更加准确、清晰;超急性期、急性期、亚急性期和慢性期梗死核心区的Lac/Cr值和Lac/NAA值高于对侧镜像区,ADC值和NAA/Cr值低于对侧镜像区,存在统计学差异（P〈0.05）;DWI的影响因素有b值、扩散系数、T2穿透效应和各向异性等,MRS的影响因素有磁场均匀性、压水压脂性能、体素、TE与TR、组织代谢物浓度和波谱采集链等。结论 DWI结合MRS能更加全面地评估缺血半暗带,更精确地对脑梗死进行分期和定位。     

磁共振扩散加权成像对宫颈癌诊断价值及其与临床病理特征的关系研究

目的:研究磁共振扩散加权成像(DWI)对宫颈癌的诊断价值及其与临床病理特征的关系。方法:将2016年5月至2018年5月间于本院接受诊治的90例宫颈癌患者作为研究组,其中鳞癌69例,腺癌21例。另选择同期因其他原因来本院行宫颈检查的90例非宫颈癌患者作为对照组,两组患者均接受常规磁共振成像(MRI)平扫及DWI检查。观察两组MRI影像学特征,分别比较研究组和对照组、不同病理分型以及不同临床病理特征宫颈癌患者表观弥散系数(ADC)值,采用受试者工作特征(ROC)曲线评价DWI检查对宫颈癌的诊断价值,并分析宫颈癌患者ADC值与临床病理特征的关系。结果:研究组和对照组的MRI影像学图像全部符合诊断和测量要求,无显著的伪影、变形;研究组患者的病变位在宫颈,其信号特征T1加权像(T1WI)显示为等信号,而T2加权像(T2WI)显示为稍高/高信号,经DWI检查显示为高信号肿块,且边界清晰。研究组患者DWI检查的ADC值低于对照组(P0.05);鳞癌患者DWI检查的ADC值也明显低于腺癌患者(P0.05)。ROC曲线结果显示,DWI检查鉴别诊断宫颈癌和非宫颈癌、鳞癌和腺癌的AUC分别为0.912、0.827。无淋巴结转移、临床病理分期为Ⅰ-Ⅱ期、中/高分化以及肿瘤细胞间质占比70%的宫颈癌患者ADC值分别高于有淋巴结转移、临床病理分期为Ⅲ-Ⅵ期、低分化以及肿瘤细胞间质占比≥70%的宫颈癌患者(均P0.05)。结论:DWI对宫颈癌诊断价值高,且DWI成像参数ADC值和宫颈癌的部分临床病理特征关系密切,能从一定程度上辅助医师了解宫颈癌病理分型、病理分期、分化程度及有无淋巴结转移。     

不同分化程度的原发性肝癌MRI初步临床研究

目的:探讨原发性肝癌不同分化程度、细胞类型的MRI图像特征、参数。方法:回顾性分析肝硬化再生结节27例、肝细胞癌75例81处病灶(高度分化15例,中度分化40例,低度分化26例)、肝内胆管癌20例的病理结果及MRI影像学数据,比较再生结节、肝细胞癌和肝内胆管癌之间,以及肝细胞癌各种组织分化程度之间的ADC值、强化程度差异。结果:常规MRI平扫结合LAVA可准确诊断大部分原发性肝癌病例。再生结节、肝细胞癌及肝内胆管癌ADC值均值的具有显著统计学差异(P0.01);肝细胞癌高分化组、中分化组及低分化组ADC值均值均具有显著统计学差异(P0.01),但中、低分化肝细胞癌ADC值均值的差异无实际临床意义;高分化肝细胞癌与肝内胆管癌ADC值均值的差异无统计学意义(P=0.27)。结论:常规MRI结合DWI、多期动态增强扫描有助于区分原发性肝癌各种组织分化程度及细胞类型。     

CT灌注、MR灌注和DWI成像综合应用在肝脏疾病的诊断价值

目的:探讨CT、MR几种功能成像(包括CT灌注、MR灌注和DWI成像)综合应用在肝脏疾病的诊断价值。方法:37例常规CT和/或MR诊断信心不足的患者,补充进行了DWI成像、CT和MR灌注成像以辅助诊断。其中,18例为肝癌术后或TACE、RFA、PEI等方法治疗后,对肝脏复发或原病灶治疗后活性情况的判断;7例为对肝内多发病灶的检出及诊断;4例肝脓肿;肝腺瘤3例,FNH5例。结果:37例患者在结合了功能成像后做出的综合影像诊断,较单纯常规CT和/或MR扫描,诊断准确率和病灶检出率均有提高。7例肝癌术后患者,常规平扫及增强扫描对术区是否有有活性的肿瘤残存还是局部复发诊断困难,DWI成像诊断为术后的炎性增生或肝脏局限性灌注异常。后患者经随访3-6个月,一般状况和生化指标无明显异常,且影像表现基本无变化。11例原发性肝癌TACE、RFA、PEI等方法治疗后的患者,CT和/或MR常规平扫及增强扫描可疑病灶仍有部分活性区但不能确定,加扫了DWI成像,其中的7例进行了MR灌注成像,6例进行了CT灌注成像。经ADC值以及灌注值的评估,病灶坏死区和残留活性区的区分更加明确。7例肝内多发病灶的患者,DWI图像较MR常规扫描检出病灶数目多且病灶显示更为清晰;4例肝脓肿、3例肝腺瘤,5例FNH患者常规CT/MR表现不典型,未能明确良恶性诊断,经DWI和灌注扫描均获明确定性,3例肝脓肿经超声导引下肝穿刺证实,2例肝腺瘤和3例FNH经受术证实,其余病例经临床及影像随访证实。结论:功能成像作为常规扫描的有益补充,其诊断价值不容忽视,可以提高病灶检出率和诊断准确率。     

D W I对脑转移瘤及胶质瘤的应用价值

目的：探讨弥散加权成像（DWI）对脑转移瘤与胶质瘤鉴别诊断的应用价值。方法：对常规MR扫描检出的42例颅内占位痛人行DWI扫描,对病人术后痛理随访后,将高级胶质瘤、低级胶质瘤及脑转移瘤各分成一组,并测定肿瘤区、水肿区、时侧正常脑组织的表观弥散系数（ADC）值及相时ADC（rADC）值。结果：低级胶质瘤与转移瘤的瘤灶rADC值比较存在差异;高级别胶质瘤与转移瘤瘤周水肿的rADC值相比较存在差异。结论：DWI及瘤灶、瘤周rADC值的定量测定对脑转移瘤与胶质瘤的鉴别诊断具有一定的临床应用价值。     

磁共振弥散加权成像及ADC值对鼻咽癌颅底放疗疗效的评价价值

目的:探讨磁共振弥散加权成像(DWI)及表观扩散系数(ADC)值在鼻咽癌颅底放疗中的临床价值。方法:收集我院于2013年6月~2014年6月复查的40例鼻咽癌患者,分别于放疗前及放疗结束12个月以后对所有患者行常规核磁共振成像(MRI)及DWI检查,测量放疗前、后ADC值,根据影像学检查以及临床诊断结果分为复发组(n=5)及未复发组(n=35)。结果:复发组放疗前ADC值为(0.797±0.031)×10~(-3)mm~2/s,与未复发组放疗前ADC值(0.805±0.028)×10~(-3)mm~2/s比较,差异无统计学意义(P0.05)。复发组放疗结束12个月以后ADC值为(1.097±0.091)×10~(-3)mm~2/s,与未复发组放疗结束12个月以后ADC值(1.705±0.128)×10~(-3)mm~2/s比较,差异有统计学意义(P0.05)。结论:DWI作为一种新兴的磁共振成像技术,对于鼻咽癌颅底放疗疗效的评价具有重要价值,通过DWI对ADC值的测量,可有效的预测患者预后是否良好。     

MRI多b值DWI序列在孤立性肺结节良恶性鉴别诊断中的价值

目的:评价MRI多b值DWI序列在孤立性肺结节(SPN)良、恶性鉴别诊断中的价值。方法:选取2015年9月-2016年6月于我院行CT检查发现并未经治疗的78例SPN患者,在穿刺活检或手术前行MRI胸部检查,根据结节直径分为三组:D1≤10mm、10 mmD2≤20 mm、20 mmD3≤30 mm,DWI扫描b值(0 s/mm~2、400 s/mm~2、600 s/mm~2、800 s/mm~2)。分别测量不同b值下结节DWI图的信号评分和拟合ADC图的表观扩散系数(ADCtot值),参照病理结果进行对比分析。结果:在b值为400 s/mm~2时,良恶性结节DWI信号差异在D1组间无统计学意义(P0.05);当b值为600 s/mm~2时,良恶性结节DWI信号差异在(D1、D2、D3)组间均具有统计学意义(P0.05),且结节信号强度越高其恶性可能性越大;在b值为800 s/mm~2时,良恶性结节DWI信号差异在D3组间无统计学意义(P0.05);在良恶性结节ADCtot值对比分析中发现,不同良性结节的ADCtot值均较恶性结节偏高,差异具有统计学意义(P0.05);以3为信号阈值,1.50×10~(-3) mm~2/s为ADCtot阈值,对SPN的特异性、准确性、阳性预测值、阴性预测值均较信号强度评分升高(P0.05)。结论:MRI弥散加权成像评价SPN过程中,多b值拟合ADCtot值对病变良恶性鉴别能力较好。在b值为600 s/mm~2时,其信号强度差异对SPN的良恶性信号评价效能最佳,多b值DWI序列对SPN良恶性的鉴别诊断具有重要价值。     

MRI检查在肝门部胆管癌诊断中的应用

目的:评价MR平扫、MRCP、DWI序列及MR动态增强扫描等不同MR检查方法对肝门部胆管癌的诊断价值。方法:回顾性分析经手术及病理证实的9例肝门部胆管癌在上述不同MRI检查方法中所显示的影像特征,提高对肝门部胆管癌的诊断认识。结论:肝门部胆管癌在MRI平扫上表现为边界不清的等、稍长T1信号稍高T2混杂信号团块,MRCP可明确显示肝门区肝管狭窄、截断征象,远侧肝管的显著扩张,DWI序列病灶表现为扩散受限稍高信号,MR动态增强扫描动脉期病变表现为不强化或轻度强化,程度不一的延迟强化较具特征性,同时增强MR对胆管壁和邻近肝实质的侵犯、血管侵犯以及肝门、腹膜后淋巴结转移有明显的诊断价值。合理选择上述多种MRI检查方法结合临床胆管癌相关抗原、CA19-9检测能对大多数肝门部胆管癌做出正确诊断,对疾病的诊断、分型、临床治疗路径选择具有重要价值。     

前列腺癌MRI灌注指标与ADC值的相关性研究

目的:探讨前列腺癌磁共振灌注加权成像和弥散加权成像参数的相关性,从影像学角度上间接反映前列腺癌微循环灌注水平与癌组织增殖的内在关系.方法:对前列腺癌病例49例,均使用GE Echo-speed1.5T超导成像仪行PWI和DWI.在工作站应用functool软件.获得PWI信号-时间曲线(signal intensity-time curve,SI-TC)图和各灌注参数相对值,并计算ADC值.结果:前列腺癌、良性前列腺增生、正常前列腺外周组织的相对负增强积分(rNEI)依次降低且具有统计学差异(P<0.05)前列腺癌的rNEI与Gleason分级、TNM、PSA分期均呈正相关关系(P<0.05)前列腺癌、良性前列腺增生和正常前列腺组织的ADC值依次升高(P<0.05).前列腺癌的rNEI与ADC呈负相关关系(P<0.05).结论:联合应用PWI和DWI可以从影像学的角度上间接提示血流供应与前列腺癌组织增殖的关系.     

磁共振灌注加权成像与弥散加权成像在脑胶质瘤分级诊断中的应用

目的:探讨磁共振灌注加权成像(perfusion weighted imaging,PWI)与弥散加权成像(diffusion weighted imaging,DWI)在脑胶质瘤分级诊断中的应用价值。方法:选取2012年1月-2017年6月在我院就诊并经病理证实为脑胶质瘤患者100例,其中高、低级别胶质瘤患者各44、56例。对所有患者行PWI、DWI检查,比较肿瘤不同区域表观扩散系数(apparent diffusion coefficient,ADC)、局部脑血流量(regional cerebral blood flow,rCBF),不同级别肿瘤实质区、瘤周水肿区rADC、rrCBF,根据ROC曲线分析rADC、rrCBF对不同级别胶质瘤的诊断阈值、敏感性、特异性。结果:与对侧相应正常脑实质比较,瘤周水肿区及肿瘤实质区ADC、rCBF均显著升高(P0.05);与瘤周水肿区比较,肿瘤实质区ADC、rCBF均显著升高(P0.05)。高级别肿瘤实质区rADC显著低于低级别肿瘤实质区(P0.05),rrCBF显著高于肿瘤实质区(P0.05)。高级别瘤周水肿区与低级别瘤周水肿区rADC间无显著差异(P0.05),高级别瘤周水肿区rrCBF显著高于低级别瘤周水肿区(P0.05)。在对高、低级别脑胶质瘤的分级中,rADC、rrCBF的曲线下面积(under the receiver operating characteristic curve,AUC)分别为0.957、0.978,均0.9。rADC诊断不同分级胶质瘤的敏感度是90.12%,特异度是95.26%,诊断阈值是13.12;rrCBF诊断不同分级胶质瘤的敏感度是92.31%,特异度是98.57%,诊断阈值是2.62。rADC与rrCBF诊断不同分级胶质瘤敏感度、特异度间无显著差异(P0.05)。结论:PWI、DWI能够为脑胶质瘤的分级诊断提供参考依据。     

MR扩散加权成像和CT及MR灌注成像对不同程度肝硬化患者的诊断价值

目的:研究MR扩散加权成像(DWI)和CT及MR灌注成像对不同程度肝硬化患者的诊断价值。方法:选择从2015年8月到2017年2月在我院治疗的肝硬化患者60例作为研究对象,根据Child-Pugh分级进行分组,其中A级32例为轻度肝硬化(记为A组),B级16例、C级12例为中重度肝硬化(记为B组),另选同期在我院进行体检的健康志愿者30例记为C组,对三组受试者分别进行DWI检查、CT及MR灌注成像,对比各组ADC值、肝脏动门脉灌注比率[SSr(ct)及SSr(mr)],采用Spearman相关性分析各指标之间的相关性。结果:三组ADC值整体比较无统计学差异(P0.05),A、B两组的ADC值较C组降低,但差异无统计学意义(P0.05)。A、B两组的ADC值比较无统计学差异(P0.05)。三组SSr(ct)、SSr(mr)整体比较,差异有统计学意义(P0.05),B组的SSr(ct)及SSr(mr)较A、C两组明显升高,差异均有统计学意义(均P0.05)。A、C两组的SSr(ct)及SSr(mr)比较无统计学差异(P0.05)。Spearman相关性分析显示,不同程度肝硬化患者的SSr(ct)与SSr(mr)呈正相关(r=0.687,P=0.000)。结论:CT以及MR灌注成像均可较好地反映出肝硬化的病变程度,且二者较DWI成像的诊断效果更佳,值得临床推广。     

High-field MR spectroscopy in the multiparametric MRI evaluation of breast lesions

IntroductionThe aim of this work was to assess the role of 3T-MR spectroscopy (MRS) in the multi-parametric MRI evaluation of breast lesions, using a pattern-recognition based classification method.Methods291 patients (301 lesions, median 2.3 cm³) were enrolled in the study (age 18–85 y, mean 54.2 y). T1-TSE (TR/TE = 400/10 ms) and T2-STIR imaging (TR/TE = 5000/60 ms), dynamic-contrast-enhanced MRI (DCE-MRI), apparent diffusion coefficient (ADC) (b = 0–800 s/mm²), and single-voxel MRS (10 × 10 × 10 mm³, PRESS, TR/TE = 3000 ms/135 ms) were performed by means of a 3T scanner. MRS results were accepted if the FWHM of the water peak was ⩽45 Hz. Total choline (tCho) was considered detected if the signal-to-noise ratio (SNR) of the 3.2 ppm peak was ⩾2. A classifier-based analysis (support-vector-machines, SVM) was performed with 4-dimensional vectors including type of margin, DCE-MRI kinetic curve type, ADC mean value, and tCho SNR. A comparison with 3-dimensional vectors (without tCho SNR) was used to assess MRS impact on sensitivity, specificity, and positive-negative predictive values (PPV-NPV) for malignancy.Results228 lesions (180 malignant/48 benign) showed acceptable spectral quality. Comparison of classification results with histopathological examination of surgical specimens showed sensitivity = 93.7%, specificity = 84.9%, PPV = 95.2%, NPV = 81.5% without the inclusion of MRS in the SVM analysis. When MRS was included, the figures increased to 95.1%, 90.7%, 97.2%, and 85.0%, respectively.ConclusionsInclusion of 3T-MRS in the multi-parametric MRI evaluation of breast lesions improved the performance of the SVM-based classifier, showing a possible role of high-field MR spectroscopy in the differential diagnosis between benign and malignant breast lesions. Further research is however needed to confirm this initial evidence.     

In situ measurement of articular cartilage deformation in intact femoropatellar joints under static loading

The deformational behavior of articular cartilage has been investigated in confined and unconfined compression experiments and indentation tests, but to date there exist no reliable data on the in situ deformation of the cartilage during static loading. The objective of the current study was to perform a systematic study into cartilage compression of intact human femoro-patellar joints under short- and long-term static loading with MR imaging. A non-metallic pneumatic pressure device was used to apply loads of 150% body weight to six joints within the extremity coil of an MRI scanner. The cartilage was delineated during the compression experiment with previously validated 2D and 3D fat-suppressed gradient echo sequences. We observed a mean (maximal) in situ deformation of 44% (57%) in patellar cartilage after 32 h of loading (mean contact pressure 3.6 MPa), the femoral cartilage showing a smaller amount of deformation than the patella. However, only around 7% of the final deformation (3% absolute deformation) occurred during the first minute of loading. A 43% fluid loss from the interstitial patellar matrix was recorded, the initial fluid flux being 0.217 +/- 0.083 microm/s, and a high inter-individual variability of the deformational behavior (coefficients of variation 11-38%). In conjunction with finite-element analyses, these data may be used to compute the load partitioning between the solid matrix and fluid phase, and to elucidate the etiologic factors relevant in mechanically induced osteoarthritis. They can also provide direct estimates of the mechanical strain to be encountered by cartilage transplants.     

MR 弥散加权成像对鉴别诊断良恶性椎体压缩性骨折的临床价值研究

目的：探讨MR弥散加权成像(DWI)鉴别诊断良恶性椎体压缩性骨折的临床价值。方法：对57 例经临床或病理证实的椎体 良恶性压缩性骨折患者行矢状位T1WI、T2WI、T2WI/FS 及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR 序列 和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数(ADC)值,并进行统计学分析。结果：(1)MR 常规序列和 DWI序列(b=500s/mm2)表现：良性椎体压缩性骨折呈长T1 长或等T2 改变,T2WI/FS 呈高信号,DWI 可以呈高信号、等信号及低 信号;恶性椎体压缩性骨折呈长T1 长T2 信号,大部分病灶T2WI/FS 及DWI呈高信号,少数变现为低信号;(2)MR 常规序列和 DWI 序列(b=500s/mm2)病灶检出率的比较：T1WI、T2WI/FS 及DWI序列病灶检出率均高于T2WI 序列,其间的差别有显著性意 义(P<0.01),T1WI、T2WI/FS 及DWI序列病灶检出率之间无显著性差异(P>0.01);(3)ADC 值比较：在DWI(b=500 s/mm2)上,良性组 ADC 值为(2.03± 0.83)× 10-3mm2/s,恶性组ADC 值为(1.37 ± 0.75)× 10-3mm2/s,正常组ADC值为(0.36± 0.21)× 10-3mm2/s,成像条 件相同时,良性组高于恶性组,两组间有明显的统计学意义(P<0.05)。结论：DWI可较好的反映椎体的弥散特征,ADC值作为量化 指标可对良恶性椎体压缩性骨折进行可靠鉴别。     

Influence of complete spinal cord injury on skeletal muscle cross-sectional area within the first 6 months of injury

In this study we examined the influence of complete spinal cord injury (SCI) on affected skeletal muscle morphology within 6 months of SCI. Magnetic resonance (MR) images of the leg and thigh were taken as soon as patients were clinically stable, on average 6 weeks post injury, and 11 and 24 weeks after SCI to assess average muscle cross-sectional area (CSA). MR images were also taken from nine able-bodied controls at two time points separated from one another by 18 weeks. The controls showed no change in any variable over time. The patients showed differential atrophy (P = 0.0001) of the ankle plantar or dorsi flexor muscles. The average CSA of m. gastrocnemius and m. soleus decreased by 24% and 12%, respectively (P = 0.0001). The m. tibialis anterior CSA showed no change (P = 0.3644). As a result of this muscle-specific atrophy, the ratio of average CSA of m. gastrocnemius to m. soleus, m. gastrocnemius to m. tibialis anterior and m. soleus to m. tibialis anterior declined (P = 0.0001). The average CSA of m, quadriceps femoris, the hamstring muscle group and the adductor muscle group decreased by 16%, 14% and 16%, respectively (P< or =0.0045). No differential atrophy was observed among these thigh muscle groups, thus the ratio of their CSAs did not change (P = 0.6210). The average CSA of atrophied skeletal muscle in the patients was 45-80% of that of age- and weight-matched able-bodied controls 24 weeks after injury. In conclusion, the results of this study suggest that there is marked loss of contractile protein early after SCI which differs among affected skeletal muscles. While the mechanism(s) responsible for loss of muscle size are not clear, it is suggested that the development of muscular imbalance as well as diminution of muscle mass would compromise force potential early after SCI.     

Integration of Diffusion Magnetic Resonance Tractography into tomotherapy radiation treatment planning for high-grade gliomas

IntroductionFractionated radiotherapy in brain tumors is commonly associated with several detrimental effects, largely related to the higher radiosensitivity of the white matter (WM) with respect to gray matter. However, no dose constraints are applied to preserve WM structures at present. Magnetic Resonance (MR) Tractography is the only technique that allows to visualize in vivo the course of WM eloquent tracts in the brain. In this study, the feasibility of integrating MR Tractography in tomotherapy treatment planning has been investigated, with the aim to spare eloquent WM regions from the dose delivered during treatment.MethodsNineteen high grade glioma patients treated with fractionated radiotherapy were enrolled. All the patients underwent pre-treatment MR imaging protocol including Diffusion Tensor Imaging (DTI) acquisitions for MR Tractography analysis. Bilateral tracts involved in several motor, language, cognitive functions were reconstructed and these fiber bundles were integrated into the Tomotherapy Treatment planning system. The original plans without tracts were compared with the optimized plans incorporating the fibers, to evaluate doses to WM structures in the two differently optimized plans.ResultsNo significant differences were found between plans in terms of planning target volume (PTV) coverage between the original plans and the optimized plans incorporating fiber tracts. Comparing the mean as well as the maximal dose (Dmean and Dmax), a significant dose reduction was found for most of the tracts. The dose sparing was more relevant for contralateral tracts (P < 0.0001).ConclusionThe integration of MR Tractography into radiotherapy planning is feasible and beneficial to preserve important WM structures without reducing the clinical goal of radiation treatment.     

Obesity and spinal loads; a combined MR imaging and subject-specific modeling investigation

Epidemiological studies have identified obesity as a possible risk factor for low back disorders. Biomechanical models can help test such hypothesis and shed light on the mechanism involved. A novel subject-specific musculoskeletal-modelling approach is introduced to estimate spinal loads during static activities in five healthy obese (BMI > 30 kg/m²) and five normal-weight (20 < BMI < 25 kg/m²) individuals. Subjects underwent T1 through S1 MR imaging thereby measuring cross-sectional-area (CSA) and moment arms of trunk muscles together with mass and center of mass (CoM) of T1-L5 segments. MR-based subject-specific models estimated spinal loads using a kinematics/optimization-driven approach. Average CSAs of muscles, moment arms of abdominal muscles, mass and sagittal moment arm of CoM of T1-L5 segments were larger in obese individuals (p < 0.05 except for the moment arm of CoMs) but moment arms of their back muscles were similar to those of normal-weight individuals (p > 0.05). Heavier subjects did not necessarily have larger muscle moment arms (e.g., they were larger in 64 kg (BMI = 20.7 kg/m²) subject than 78 kg (BMI = 24.6 kg/m²) subject) or greater T1-L5 trunk weight (e.g., the 97 kg (BMI = 31 kg/m²) subject had similar trunk weight as 109 kg (BMI = 33.3 kg/m²) subject). Obese individuals had in average greater spinal loads than normal-weight ones but heavier subjects did not necessarily have greater spinal loads (117 kg (BMI = 40.0 kg/m²) subject had rather similar L5-S1 compression as 105 kg (BMI = 34.7 kg/m²) subject). Predicted L4-L5 intradiscal pressures for the normal-weight subjects ranged close to the measured values (R² = 0.85–0.92). Obese individuals did not necessarily have greater IDPs than normal-weight ones.     

MR弥散加权成像对鉴别诊断良恶性椎体压缩性骨折的临床价值研究

目的：探讨MR弥散加权成像（DWI）鉴别诊断良恶性椎体压缩性骨折的临床价值。方法：对57例经临床或病理证实的椎体良恶性压缩性骨折患者行矢状位T1M、T2WI、T2WI／FS及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR序列和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数（ADC）值,并进行统计学分析。结果：（1）MR常规序列和DWI序列（b=500s／mm2）表现：良性椎体压缩性骨折呈长T1长或等T2改变,T2WI／FS呈高信号,DWI可以呈高信号、等信号及低信号;恶性椎体压缩性骨折呈长T1长T2信号,大部分病灶T2WUFS及DWI呈高信号,少数变现为低信号;（2）MR常规序列和DWI序列（b=500s／mm2）病灶检出率的比较：T1WI、T2WI／FS及DWI序列病灶检出率均高于T2WI序列,其间的差别有显著性意义（P〈0．01）,T1WI、T2WI／FS及DWI序列病灶检出率之间无显著性差异（P〉0．01）;（3）ADC值比较：在DWI（b=500s／mm2）上,良性组ADC值为（2．03±0．83）×10^3mm^2/s,恶性组ADC值为（1．37±0．75）×10^-3mm^2/s,正常组ADC值为（0．36±0．21）×10^-3mm^2／s,成像条件相同时,良性组高于恶性组,两组间有明显的统计学意义（P〈0．05）。结论：DWI可较好的反映椎体的弥散特征,ADC值作为量化指标可对良恶性椎体压缩性骨折进行可靠鉴别。     

RGD肽介导的MR分子探针在体外结直肠癌细胞的显像及对其生物学行为的影响

目的：探讨RGD肽介导的MR分子探针在体外结直肠癌细胞的MRJ显像及对其生物学行为的影响。方法：利用纳米技术构建靶向RGD荧光纳米MR、探针,利用荧光倒置相、差显微镜观察该探针与LOVO细胞结合情况;体外磁共振成像（MRI）显像;利用细胞克隆实验测其增殖活性;流式细胞术检测其细胞周期、凋亡。结果：荧光相差显微镜示该RGD肽介导的MR分子探针能特异性与LOVO细胞结合;体外MRI成像示靶向RGD组T1信号强度高于非靶向组及对照组（P〈0．05）;该探针作用24h后的LOVO细胞增殖活性降低,细胞分裂周期发生变化,阻滞在S＋G2M期的细胞比例上升,细胞凋亡率与其他两组相比有显著增加（P〈0．05）。结论：该RGD肽介导的MR分子探针能与结直肠癌LOVO细胞靶向结合,能增强MR1的显像效果,并对肿瘤细胞具有一定的抑制作用．