DWI诊断外伤性椎体压缩骨折优化b值的初步研究

目的 应用1.5T磁共振采用不同b值对骨折椎体行扩散加权成像（DWI）检查,通过数据分析优选最佳b值。方法 根据外伤时间,按T〈7天、14天≤T〈30天将患者分为二组,每组20例,共40例。所有入组病例均行DWI检查,采用单次激发自旋回波平面成像序列,b值分别取200、300、400、500、600、700、800、900、1 000s/mm^2,测量骨折椎体表观扩散系数（ADC）值并对比不同b值下椎体扩散加权成像（DWI）图像质量,应用ROC曲线分析不同b值下ADC值对不同时间段椎体压缩骨折的诊断价值。结果 40例受检者骨折椎体DWI图像,随着b值由200s/mm^2升高至1 000s/mm^2,图像信噪比逐渐降低,b值为300s/mm^2时图像对比噪声比最高;b值为200、300、400、500、600、700、800、900、1000s/mm^2时不同时间段压缩骨折ADC值的差异均有统计学意义（P〈0.01）;b值为300s/mm^2时诊断新近压缩骨折（T〈7天）价值最大,其诊断敏感度、特异度分别为86.76%、81.87%。结论 b值为300s/mm^2时,椎体DWI图像质量佳,所获得的ADC值诊断效能相对较高。     

ADC图和动态增强平面回波MR序列评价头颈部癌的颈部淋巴结转移

目的：评价ADC图和动态增强平面回波MR序列对诊断头颈部癌颈部淋巴结转移的临床应用价值。方法：对51名头颈部癌伴颈部淋巴结病变的患行扩散加权（DWI）和动态增强T2。灌注加权。DWI采用单次激发EPI序列，b值为500和1000s／mm^2，并重建出ADC图。多层面MR灌注成像采用单次激发平面回波T2WI，在首过团注Gadolinium-DTPA（0．2ml mol／kgBW）后每两秒采集一次，共采集2min以获得信号强度时间曲线。计算出淋巴结的ADC值和最大信号强度下降的百分比，并与组织病理学进行对照。     

弥散加权成像鉴别乳腺良恶性病变的价值初探

目的　探讨弥散加权成像（diffusionweightedimaging,DWI）的表面弥散系数（apparentdiffusioncoefficients,ADC）鉴别乳腺良恶性病变的价值。方法　健康志愿者10人,经手术病理证实的乳腺病变49例,其中恶性肿瘤26例,良性病变23例。DWI采用单次激发回波平面成像（echo-planarimaging,EPI）技术,14例取5个b值（b为扩散敏感度）,余者取2个b值,计算ADC值。以恶性肿瘤ADC值单侧上界95%容许区间为界限判断病灶的良恶性,诊断结果与动态增强比较。结果　除1例原位癌和1例小腺瘤外,DWI显示所有良恶性病变。恶性肿瘤组ADC值为(0.9608±0.2043)×10     

MR化学位移成像在脊柱病变中的应用研究

目的:评价同、反相位化学位移成像中的信号改变及信号强度比在鉴别脊柱良、恶性病变中的应用价值。方法:63例脊柱病变患者行MRI梯度回波同/反相位检查,良性病变36例,恶性病变27例,并以63例中的正常椎体作为正常组。分析病变椎体在同、反相位上的信号改变及其信号强度比(反相位信号强度/同相位信号强度),对三组信号强度比值进行统计学分析。结果:19(52.8%)例椎体良性病变组显示为反相位低信号、同相位高信号;16(59.3%)例椎体恶性病变显示为反相位高信号、同相位低信号。正常椎体组、椎体良性病变组及椎体恶性病变组的信号强度比均数和标准差分别为:0.71±0.17、0.90±0.13和1.04±0.20(P<0.01)。结论:梯度回波MRI同、反相位成像的病灶信号强度改变及信号强度比对预测椎体良恶性病变的性质有重要价值。     

MR化学位移成像技术在椎体良恶性病变中的鉴别诊断价值

目的 探讨MR化学位移成像(chemical shift imaging,CSI)技术在椎体良恶性病变中的鉴别诊断价值.资料与方法 32例共47个椎体病变均行MRI常规扫描和同相位、反相位成像,在病变椎体上设置感兴趣区(ROI),在同相位及反相位图像的同一位置分别测量其信号强度值,计算椎体信号强度变化的百分比,即(同相位信号强度-反相位信号强度)/同相位信号强度,并对良性组与恶性组之间进行统计学分析.结果 终板变性、许莫氏结节伴水肿、血管瘤、良性压缩性骨折和转移椎体信号程度下降值分别为52.2%、58.0%、49.4%、49.3%和3.5%.良性组明显高于恶性组(P<0.01).将15%定为良、恶性椎体病变信号下降的临界值,诊断的敏感性为85.2%,特异性为94.6%.结论 病变椎体信号强度下降超过15%可以作为鉴别良、恶性椎体病变的临界值,CSI技术对椎体良、恶性病变具有重要的鉴别诊断价值.     

MR水、脂分离Dixon方法及弥散成像对椎体骨折性质的鉴别研究

目的探讨磁共振脂肪抑制Dixon技术水、脂分离及弥散成像在椎体骨折性质的诊断和鉴别诊断中的应用价值。方法收集病理及临床随访证实的椎体良性压缩性骨折22例25个椎体,包括骨质疏松性压缩性骨折15例,外伤性骨折7例;恶性压缩性骨折20例35个椎体,包括转移瘤19例,骨髓瘤1例。对所有患者行MRI常规矢状位T1WI、T2WI、横断位T2WI序列;T2WI Dixon、DWI、DTI序列扫描。结果良性压缩性骨折组脂肪信号分数平均值为(0.25±0.01),恶性压缩性骨折组脂肪信号分数平均值为(0.09±0.04),组间差异均有统计学意义(P0.01)。良性压缩性骨折组与恶性压缩性骨折组ADC值间差异有统计学意义(P0.01)。良性压缩性骨折组与恶性压缩性骨折组FA值差异无统计学意义(P0.05)。对FF值及ADC值绘制良、恶性ROC曲线,得出良恶性椎体压缩性骨折诊断的临界值分别为0.136、1.409×10-3 mm2/s。结论磁共振FF值及ADC值参数结合有助于椎体骨折性质的诊断和鉴别诊断。     

椎体压缩性骨折的影像学诊断

目的探讨MR扫描对椎体原发性骨质疏松压缩性骨折及转移瘤所致的压缩性骨折的诊断及鉴别诊断的价值及表现。材料与方法对30例椎体原发性骨质疏松压缩性骨折和30例转移瘤压缩性骨折进行回顾性分析。结果椎体原发性骨质疏松性压缩骨折的特点椎体变形可分为楔形变、双凹形、扁平形,椎体后上角后突入椎管具有特异性;椎体信号特点椎体终板下或椎体中央带状T1WI低信号或椎体后部等信号外,椎体前部低信号,增强扫描后椎体信号强度与相邻正常椎体相同。转移瘤所致压缩性骨折的特点椎体后部皮质后突,T1WI上椎体内及椎弓根弥漫性低信号,增强扫描呈明显不均匀强化。结论增强扫描和非增强扫描的MR检查对椎体良恶性压缩骨折的鉴别有一定的价值。     

磁共振扩散加权成像对椎体良恶性骨折的鉴别诊断价值

目的探讨磁共振扩散加权成像(DWI)在椎体良恶性骨折中的鉴别诊断价值。方法31例共58个病变椎体均做了MRI常规扫描和扩散加权成像,良性组20例32个骨折椎体,恶性组8例18个椎体,结核组3例8个椎体,正常对照组31个椎体。b值为600s/mm2,分析病变椎体与正常椎体DWI信号特点,并测定ADC值,定量分析比较病变组与对照组之间,良、恶性组,恶性组与结核组之间ADC值有无统计学差异。结果良性组、恶性组、结核组以及对照组ADC值分别为(1.44±0.41)×10-3mm2/s、(0.94±0.17)×10-3mm2/s、(0.98±0.13)×10-3mm2/s、(0.42±0.16)×10-3mm2/s。病变组ADC值均显著高于对照组(P<0.001),良性组明显高于恶性组(P<0.01),恶性组与结核组无统计学差异(P>0.05)。以恶性组95%可信区间上界1.02×10-3mm2/s定为良恶性椎体骨折ADC值界值,诊断敏感性72.2%,特异性90.6%。结论DWI对脊椎良恶性骨折具有重要的鉴别诊断价值,可作为常规MRI检查的重要补充手段。     

MR扩散加权成像定量分析对纵隔良恶性病变的鉴别诊断

目的探讨MR扩散加权成像对纵隔良恶性病变的鉴别诊断价值。材料与方法对53例纵隔病变进行传统的T1WI和T2WI,并在b=0和b=1000s/mm2下行扩散加权成像,计算其表观扩散系数ADC值。用t检验对这两组ADC值     

椎体良恶性压缩性骨折的MRI表现及其诊断

目的探讨脊椎良恶性压缩性骨折的MRI表现及其诊断.材料和方法回顾性分析171例201个椎体压缩性骨折的MRI表现,按良恶性病因分类.结果87%(71/82)恶性骨折无骨髓信号;83%(43/52)骨质疏松骨折完全保留骨髓信号."倒楔形”及"扁形”盘状压缩是恶性肿瘤压缩较典型表现."扁形”凹状压缩、椎体后上角突向椎管、T1WI椎体终板下带状低信号是椎体骨质疏松压缩的较典型表现.结合外伤史、发现骨折线、多伴骨髓信号改变为外伤骨折的诊断要点.结论MRI对良恶性脊椎压缩性骨折的诊断及鉴别诊断有较大意义.     

MR弥散技术对脊柱压缩性骨折诊断价值初探

目的：初步评价MR弥散技术对脊柱单纯性和病理性压缩性骨折的诊断价值。方法：7l例脊柱椎体压缩性骨折行X线、MRI平扫和弥散序列检查(35例加作增强扫描)，其中53例另作CT检查。病理性骨折38例(包括转移性肿瘤29例，骨髓瘤4例，嗜酸性肉芽肿2例，结核3例)；单纯性分析33例(包括单纯外伤所致18例，骨质疏松所致l5例)。病理性分析者行CT引导下经皮骨穿刺检查或手术病理证实；外伤或骨质疏松所致椎体压缩性骨折均符合临床、实验室检查及MRI表现，部分经随访证实。结果：急性单纯性压缩性骨折和病理性骨折在常规MRI上有各自的特点。9％(3／33)单纯性压缩性骨折在DWI表现为等低信号混有条状高信号；24％(8／33)表现为等低信号；67％(22／33)表现为高信号。93％(36／38)病理性椎体压缩性骨折DWI上表现为高信号；7％(2／38)表现为等低信号。DWI上均至高信号的单纯性压缩和病理性压缩经统计分析无显著性意义(P＞0．05)。结论：单凭MRI弥散序列的信号改变不能非常准确地鉴别脊柱单纯性压缩性分析和病理性骨折，需进一步深入定量研究。     

MR多种成像技术在原发性骨质疏松椎体骨折鉴别诊断中的应用

目的 :探讨MR多种成像技术对鉴别原发性骨质疏松椎体骨折与其它原因所致病理性骨折的价值。方法 :对14例原发性骨质疏松椎体压缩骨折和 2 0例转移瘤所致骨折患者行MRI检查 ,成像序列均包括SET1 WI、FSET2 WI、STIR、DWI和增强SET1 WI抑脂序列 ,分析病变椎体在不同MR成像序列上的信号表现 ,计算病变区的强化比率、ADC值和骨髓对比率 ,进行统计学分析。结果 :SET1 WI、FSET2 WI、STIR和增强扫描上病变椎体横形分层样信号、椎体后上角后突及前后径增加、附件信号异常、邻近椎间盘信号增高、局部软组织肿块及椎管内结构受累在两组间发生率差异明显 ,骨质疏松骨折与转移瘤所致骨折的ADC值无显著性差异 (P >0 .0 5 ) ,两者强化比率和骨髓对比率有显著性差异 (P <0 .0 1)。结论 :MR多种成像技术联合应用对原发性骨质疏松椎体骨折与其它原因所致病理性骨折的鉴别可提供很大帮助     

Methods and applications of diffusion imaging of vertebral bone marrow

Diffusion-weighted imaging (DWI) is an MRI technique that is sensitive to random water movements at spatial scales far below typical MRI voxel dimensions. DWI is a valuable tool for the diagnoses of diseases that involve alterations in water mobility. In the spine, DWI has proven to be a highly useful method for the differential diagnosis of benign and malignant compression fractures. In these pathologies, the microscopic structure of bone marrow is altered in a very different ways, leading to different water mobility, which can be depicted by DWI. Most of the pulse sequences developed for MRI can be adapted for DWI. However, these DWI-adapted sequences are frequently affected by artifacts, mostly caused by physiological motion. Therefore, the introduction of additional correction techniques, or even the development of new sequences is necessary. The first part of this article describes the principles of DWI and the sequences used for DWI of the spine: spin echo (SE), turbo spin echo (TSE), single-shot echo planar imaging (EPI), and steady-state free precession (SSFP) sequences. In the second part, clinical applications of DWI of the spinal bone marrow are extensively discussed.     

磁共振扩散加权成像在甲状腺良恶性病变鉴别诊断中的价值

目的：探讨MR扩散加权成像在甲状腺良恶性病变鉴别诊断中的价值。方法：采用平面回波成像（EPI）技术。对50例甲状腺局灶性病变（良性组36例,恶性组14例）行DWI检查,分别测量b值取0、150、300和500s/mm2时良恶性病灶的信号强度和ADC值,并比较其差异。所有患者均经手术（49例）或活检（1例）病理证实。结果：良性与恶性病变的信号强度在b值为0、150、300和500s/mm2时差异均无统计学意义（P〉0.05）。b值为150、300和500s/mm2时良性组与恶性组之间ADC值的差异均有统计学意义（P〈0.01）。以恶性组ADC值95%可信区间上限作为诊断阈值,则b值为150、300和500s/mm2时,诊断阈值分别为1.992×10^-3、1.582×10-3和1.410×10-3mm2/s。应用ROC曲线分析不同b值时ADC阈值诊断恶性病变的作用,显示b值为150s/mm2时价值最大,其诊断敏感度、特异度、符合率、阳性和阴性预测值分别为78.57%、84.62%、82.50%、73.33%和88.00%。结论：甲状腺恶性病变的ADC值低于良性病变,b值取150s/mm2、阈值设为1.992×10-3mm2/s有助于良恶性病变的鉴别。     

SSH-EPI diffusion-weighted MR imaging of the spine with low b values: is it useful in differentiating malignant metastatic tumor infiltration from benign fracture edema?

Objective  Conventional MR sequences are sometimes not helpful in differentiating benign from pathologic fractures. Our aim was to evaluate the usefulness of single-shot echo-planar imaging sequences (diffusion-weighted imaging (DWI)/SSH-EPI) with low b value in differentiating malignant metastatic tumor infiltration of vertebral bone marrow from benign vertebral fracture edema. Materials and methods  A total of 47 patients, 20 with benign fractures and 27 with tumor infiltration, were included in this prospective study. Diffusion-weighted MR images were obtained by single-shot echo-planar imaging technique with diffusion gradient (b = 300 s/mm²; TR/TE, 1,400/100), using a 1.5 T MR scanner. T1- and T2-weighted images and short inversion time inversion-recovery images were available for all 64 lesions. The lesions on DWI/SSH-EPI were categorized as having hypo-, iso-, or hyperintense signal intensity relative to normal vertebrae by two experienced radiologists. Results  We evaluated signal intensity patterns on DWI/SSH-EPI in 64 lesions, which showed low signal intensity on T1-weighted images in both benign fractures and metastasis. With the exception of sclerotic metastases in two patients, malignant metastatic tumor infiltration was hyperintense with respect to normal bone marrow on diffusion-weighted images; all but four benign vertebral fractures were isointense with respect to normal bone marrow. Conclusion  Single-shot echo-planar imaging sequences (DWI/SSH-EPI) with low b value provided excellent distinction between metastatic tumor infiltration and benign vertebral fracture edema. Hyperintense signal intensity on DWI/SSH-EPI was highly specific for the diagnosis of metastatic tumor infiltration of the spine.     

良恶性多椎体压缩性骨折的MRI诊断

目的:探讨良、恶性多椎体压缩性骨折的MR影像学特征。方法:回顾220例(良性104例,恶性116例)460个压缩椎体,比较病变椎体排列特性及MRI征象。结果:恶性多椎体压缩骨折,椎体跳跃式侵犯多见,66%的病灶集中在椎体后2/3髓质,T1WI呈穿凿样、片状低信号,并椎弓根、椎板表现膨胀性骨质破坏,椎间盘形态正常;良性多椎体压缩性骨折,椎体连续性病变多见,终板表现带状异常信号,常伴椎间盘撕裂、椎间隙狭窄或增宽,椎体碎裂,但无软组织肿块。结论:MR的特征性改变能准确鉴别良、恶性压缩骨折。     

Single shot fast spin echo diffusion-weighted MR imaging of the spine; Is it useful in differentiating malignant metastatic tumor infiltration from benign fracture edema?

PURPOSE: This study aims to evaluate the usefulness of single shot fast spin echo diffusion-weighted MR imaging (DWSSFSE) in differentiating malignant metastatic tumor infiltration of vertebral bone marrow from benign vertebral fracture edema. MATERIALS AND METHODS: Forty-six consecutive patients with 59 acute osteoporotic or traumatic vertebral fractures (mean age = 59) and 31 patients with 98 vertebral metastasis including 20 pathologic fractures (mean age = 53) were included in this study. Diffusion-weighted MR images were obtained by single-shot fast spin echo technique with diffusion gradient (b = 500 s/mm2, TR/TE: 5002/99) by using a 1.5 T MR scanner (Signa MR/i; GE Medical Systems, Milwaukee, WI, USA). T1- and T2-weighted images and short inversion time inversion-recovery (STIR) images were available in all 157 lesions, while contrast-enhanced images were available in 98 metastatic lesions. We evaluated signal intensity patterns on DWSSFSE in 157 lesions, which showed low signal intensity on T1-weighted images in both benign fractures and metastasis. The lesions on DWSSFSE were categorized as low, intermediate, and high signal intensity relative to presumed normal vertebra by concordant inspection of two experienced musculoskeletal radiologists. RESULTS: In benign fractures, DWSSFSE images showed low signal intensity in 56 vertebrae (95%) in 43 patients (93%) and intermediate signal intensity in only 3 vertebrae (5%) in 3 patients (7%). On the other hand, metastases most commonly had low signal intensity in 57 vertebrae (58%) in 25 patients (80%), intermediate signal intensity in 35 vertebrae (36%) in 16 patients (52%), and high signal intensity in 6 vertebrae (6%) in 3 patients (10%). Thus, intermediate and high signal intensities are far more common than benign fractures. Such differences in signal intensity were statistically significant (chi-square test, P < .05). High or intermediate signal intensity on DWSSFSE was highly specific for the diagnosis of metastatic tumor infiltration of the spine (sensitivity: 42%; specificity: 95%; true positive rate: 93%; false negative rate: 52%). CONCLUSIONS: DWSSFSE of the spine may be useful in differentiating metastatic tumor infiltration of vertebral bone marrow from benign fracture edema.     

椎体压缩性骨折的磁共振诊断

目的分析椎体良、恶性压缩性骨折的MRI表现.材料和方法22例椎体良性压缩性骨折及49例病理性压缩性骨折患者,男43例,女28例,年龄34～76岁,平均58.3岁.全部行MR平扫+增强扫描.结果压缩椎体的信号改变对骨折甚为敏感,但对良、恶性骨折的鉴别缺乏特异性.压缩椎体残留有正常的骨髓信号者多见于良性骨折(P＜0.001).压缩椎体后缘膨出、椎管狭窄常见于病理性骨折(P＜0.001).椎弓根受侵(P＜0.001)及椎旁软组织肿块(P＜0.001)是病理性骨折所特有的征象.增强后椎体信号均匀与否对诊断有帮助(P＜0.001).结论病理性压缩性骨折多表现为椎弓根信号异常,椎体后缘明显膨隆,椎管狭窄,椎旁软组织肿块及增强后压缩椎体不均匀强化.椎弓根变形膨大一般不出现于良性骨折.     

对良、恶性椎体压缩性骨折MRI鉴别诊断的再认识

目的：提高对椎体压缩性骨折定性征象的认识。方法：回顾性分析经临床确诊的椎体压缩性骨折56例78个椎体，外伤性骨折11例15个椎体；非外伤性骨折17例25个椎体；恶性压缩性骨折28例38个椎体，MRl分别重点观察了椎体骨髓信号、椎体后缘的形态、MRI增强的强化方式、椎弓根的形态及椎旁软组织的形态。结果：恶性压缩性骨折较特异性的MRI征象有：(1)L1WI像上椎体呈广泛均匀低信号；(2)椎体后缘呈球形凸出；(3)T2WI像上椎弓根膨大且可见高信号；(4)T2WI／I像受累椎体的不均一强化；(5)瘤样椎旁软组织肿块。结论：MRI的特征性改变能准确地鉴别良、恶性椎体压缩性骨折。     

DWI在鉴别脊椎良恶性病变中的应用价值

目的:探讨DWI在鉴别脊椎良恶性病变中的应用价值。方法:分析经病理和/(或)临床随访证实的脊柱压缩性骨折患者共50例82个病变椎体,其中良性组20例,34个椎体;恶性组30例,48个椎体。选取50例中的正常椎体35例共35节椎体作为对照组。均行MRI常规序列及DWI扫描;分析良恶性病变的DWI信号特点,并定量测定3组椎体的ADC值,进行统计学分析。结果:良性及恶性组病灶DWI序列均可表现为高、等、低或混杂信号,且2组信号表现差异无统计学意义;良性组、恶性组、对照组ADC值分别为(2.23±0.25)×10-3 mm2/s,(1.62±0.27)×10-3 mm2/s及(0.43±0.34)×10-3 mm2/s,经t检验,各组间ADC值差异均有统计学意义(P<0.05)。结论:DWI信号改变不能用于鉴别椎体良恶性病变,而ADC值具有重要的鉴别诊断价值。