正常人膝关节软骨MR成像和软骨重建

目的　研究正常人膝关节软骨的MR成像和软骨三维重建方法 ,为临床诊治关节软骨病变提供科学依据。材料与方法　使用Philips 1.0T磁共振成像仪对 2 0例志愿者行软骨序列扫描 ,然后进行三维软骨重建。 结果　软骨序列及软骨重建技术可以清晰显示软骨的结构 ,关节软骨在SE序列上显示为 3层结构 ,在SPIR/ 3D/FFE/T1WI上最多显示为 4层结构 ,重建后的软骨像具有立体直观的效果 ,并具有良好的空间分辨率。结论　软骨MR成像和软骨重建能清晰显示膝关节的软骨结构 ,可为临床对骨关节病变的诊断和治疗提供帮助。     

磁共振水激发MEDIC3D序列在膝关节成像中的应用

目的 对比分析磁共振水激发多回波合并成像(multiple-echo data image combination,MEDIC)序列、快速自旋回波质子密度加权成像(fast spin-echo proton density-weighted imaging,PDWI)序列、脂肪抑制(turbo inversion recovery magnitude,TIRM)序列在膝关节软骨损伤、软骨下骨水肿、半月板损伤显示方面的临床应用.方法 对30例受检者采用SIEMENS Magnetom Avanto 1.5T磁共振成像系统行常规膝关节MRI扫描后加扫水激发MEDIC3D序列.比较水激发MEDIC3D与常规PDWI图像和T2WI-TIRM图像显示的关节软骨损伤、软骨下骨水肿、半月板损伤的各自检出率.结果 30例患者中,水激发MEDIC3D组检出27例关节软骨损伤(诊断检出率90%),27例半月板损伤(诊断检出率90%),14例软骨下骨水肿(诊断检出率46.7%).PDWI组检出关节软骨损伤12例(诊断检出率40%),半月板损伤18例(诊断检出率60%).T2WI-TIRM组检出软骨下水肿17例(诊断检出率56.7%).水激发MEDIC3D图像显示关节软骨损伤、半月板损伤检出率高于常规PDWI组图像,差异有显著性意义(P<0.05);水激发MEDIC3D图像显示软骨下骨水肿的检出率与T2WI-TIRM序列的比较差异无统计学意义(P>0.05).结论 磁共振水激发MEDIC3D序列对膝关节软骨损伤和半月板损伤的显示明显优于常规PDWI图像,具有重要临床应用价值.     

3D FIESTA在膝关节MRI检查中的应用

膝关节MR I检查由于对软组织具有高分辨率、多平面成像,能清晰显示半月板、交叉韧带、关节软骨、滑膜、关节囊腔及副韧带等解剖结构,为临床提供丰富的诊断信息及无创性而被临床广泛的应用。由于膝关节交叉韧带的解剖结构及走行特点,在常规检查中有时显示不清,笔者试用3D FIESTA序列来探讨交叉韧带的显示情况。1材料与方法1.1病例资料21例患者,男14例,女7例,均有不同程度的膝关节疼痛、功能受限等临床症状。外伤引起者16例,老年性骨关节病者4例,其它原因引起者1例。1.2扫描方法对21例患者进行常规检查及3D FIESTA序列扫描。序列为矢状…     

膝关节软骨损伤的MR诊断及与关节镜结果对照

目的分析不同MR扫描序列对关节软骨损伤的诊断能力，为关节软骨损伤的临床诊断和治疗提供可靠的影像学依据。方法对临床拟行膝关节镜检查的膝关节疼痛患者进行术前MR成像，对MR图像进行二维和三维重建处理。结果与关节镜对照，34例膝关节软骨损伤患者的MR检查结果：脂肪抑制三维稳态进动快速成像序列(fat-saturated three-dimensional fast imaging with steady-state procession，FS-3D-FISP)敏感度为91．4％、特异度为97％、Kappa值为0．818，脂肪抑制二维快速小角度激发成像序列(fat-saturated tow-dimensional fast low angle shot，FS-2D-FLASH)敏感度为77．1％、特异度为98％、Kappa值为0．531，SE-T1WI序列敏感度为70％、特异度为99％、Kappa值为0．518。本组无明确急性外伤史的关节软骨损伤病例中有77．6％在病变部位出现与损伤软骨区相对应的软骨下骨及骨髓内片状T1WI低信号影，FS-3D-FISP及FS-2D-FLASH序列呈高信号。结论FS-3D-FISP序列对关节软骨损伤病变的准确性明显优于FS-2D-FLASH和SE-T1WI，与关节镜诊断结果之间具有良好的一致性。软骨下骨及骨髓内的异常信号是关节软骨损伤重要的间接征象。关节软骨损伤的三维成像有利于临床术前对重度膝关节软骨损伤进行立体定位诊断。     

磁共振3D-SPACE、3D-TrueFISP、2D-FSE-PD序列膝关节软骨成像的比较研究

目的：比较三维可变反转角快速自旋回波序列(3D-SPACE)、三维真稳态进动快速成像序列(3D-Ture FISP)以及二维快速自旋回波质子像序列(2D-FSE-PD)膝关节软骨的成像质量。方法40例健康志愿者和20例患者在1.5T MR 上行3D-SPACE、3D-True FISP 和2D-FSE-PD 序列成像。比较各序列软骨信噪比(SNR)、对比信噪比(CNR)、损伤显示能力。结果3种序列中,3D-SPACE 序列的软骨信噪比、滑液与软骨的对比信噪比最高。3D-SPACE 比3D-True FISP 能更好地显示膝关节软骨的Ⅰ、Ⅱ级损伤,在软骨的Ⅲ、Ⅳ级损伤中,3D-SPACE 与3D-True FISP 无明显差异,对于各级软骨损伤,3D 序列均好于2D 序列。结论相比3D-True FISP、2D-FSE-PD 序列,3D-SPACE 序列能更好地显示膝关节软骨结构和损伤。     

正常成年人膝关节软骨的MR多序列比较研究

目的　探讨正常成年人膝关节软骨的多序列MR表现及厚度 ,比较其优缺点。方法　选取健康成年志愿者 3 0名 ,男 18名 ,女 12名 ,分别计算并比较T1 WI、T2 WI、PDWI、短 -TI反转恢复序列 (STIR)和三维脂肪抑制扰相梯度回波序列 (3D -FS -SPGR)关节软骨同生理盐水、骨髓和肌肉的对比度噪声比 (CNR) ,观察各序列软骨的MR表现、三维重建并测量软骨厚度。结果　 3D -FS -SPGR序列关节软骨同生理盐水、骨髓和肌肉的CNR值均与其他序列有显著性差异 ;T1 WI和PDWI序列关节软骨约 5 0 % (13 5 0 )表现为 3层改变 ,T2 WI和STIR序列则均表现为单层改变 ,3D -FS -SPGR序列软骨分层与软骨厚度有关 ,最多可见 5层改变 ;3D -FS-SPGR序列软骨厚度的测量值较其他序列准确 ,本组正常男性与女性膝关节各部位关节软骨的平均厚度分别为 (2 .63± 0 .69)mm和 (2 .5 2± 0 .62 )mm。结论　SE序列 ,特别是T1 WI软骨的分层改变与其组织学结构有关 ,但 3D -FS -SPGR序列软骨的分层是由“截断伪影”所致。 3D -FS -SPGR序列较其他序列有着明显的优势 ,能使关节软骨显示更加清晰 ,厚度测量更加准确 ,结合三维重建技术能为临床诊断与治疗提供更多的信息     

显示正常人膝关节软骨分层的最佳MRI序列

目的:显示正常人膝关节软骨分层的最佳MRI序列,为关节病变的早期诊断提供技术支持.方法:选择无膝关节症状的志愿者140例,分别采用SE-T1WI、脂肪抑制二维快速小角度激发(FS -2D-FLASH)和脂肪抑制三维稳态旋进快速成像(FS-3D-FISP)三个扫描序列,行膝关节矢状面扫描.分析显示软骨分层的最佳MRI序列.结果:FLASH序列显示结果为140例中有129例显示膝关节软骨分3层,9例无分层,2例可见分5层,显示分层例数多,分层清楚,扫描时间较短;SE序列140例中有101例显示膝关节软骨分3层,39例无分层,未见分5层者,显示分层例数较少;FISP序列140例中有133例显示膝关节软骨分3层,5例无分层,2例分5层,显示分层例数多,但分层模糊,扫描时间长.结论:FS-FLASH-2D序列是显示膝关节软骨分层的最佳序列.     

磁共振3D-TSE(SPACE)序列在评估健康受试者踝关节解剖结构的应用研究

目的 分析3T磁共振3D-TSE(SPACE)序列及常规2D-TSE序列对健康受试者踝关节解剖细节显示的价值.方法 选取30例健康受试者踝关节进行磁共振成像(年龄22~29岁,平均25岁),使用Siemens Magneton Trio Tim 3.0T磁共振扫描仪及膝关节线圈.本研究所使用的MRI序列为二维脂肪抑制T2加权(2D-FS-T2WI-TSE)和三维脂肪抑制T2加权快速自旋回波(perfection with application optimized contrasts using different flip angle evolutions,3D-FS-T2WI-SPACE).扫描范围包括踝关节的冠状位、矢状位和轴位.分别计算胫距关节骨软骨,跟骨骨髓,比目鱼肌,胫距关节腔关节液,跟腱及距腓后韧带的信噪比(SNR);分别计算关节液-软骨,关节液-韧带的对比噪声比(CNR).分别就伪影、毗邻结构的鉴别、信号均一性、部分容积效应以及韧带结构起止点等方面来评价2个序列显示图像质量的能力;就感兴趣韧带或肌腱进行任意曲面重建,显示其全长.结果 SPACE序列上各结构SNR及CNR显著优于常规2D序列,二者之间的差异具有统计学意义(P<0.05).就图像质量的评估方面,SPACE序列与常规2D序列之间显示结果一致,二者之间的差异没有统计学意义(P>0.05).结论 SPACE是一种新的磁共振成像序列,可以进行不同加权图像的扫描,对踝关节正常解剖结构的显示清晰,可以满足临床诊断的需要.     

磁共振SPIR-3D-FFE-T_1WI序列对膝关节早期剥脱性骨软骨炎软骨损伤的实验研究

目的:研究SPIR-3D-FFE-T1WI扫描序列对膝关节早期剥脱性骨软骨炎软骨损伤的诊断能力,为剥脱性骨软骨炎的临床诊断和治疗提供可靠的影像学依据.方法:牛膝关节25只,分别制作关节软骨损伤模型,扫描序列采用SPIR-3D-FFE-T1WI扫描序列.评价牛膝关节剥脱性骨软骨炎软骨损伤模型的MRI特点.结果:牛膝关节剥脱性骨软骨炎软骨损伤模型MR检查结果:SPIR-3D-FFE-T1WI序列敏感度为93.4%,特异度为98%.结论:SPIR-3D-FFE-T1WI序列有利于膝关节剥脱性骨软骨炎软骨损伤的早期诊断.     

MR 3D SPGR、3D FIESTA和2D SE/FSE序列对外伤性膝关节软骨损伤的分级诊断研究

目的 回顾性研究外伤性膝关节关节软骨的损伤发生率及程度,比较三维扰相梯度回波序列(3DSPGR)、三维稳态采集快速成像序列(3D FIESTA)和膝关节常规检查序列(2D SE/FSE)在诊断外伤性膝关节软骨损伤中的准确性.资料与方法 45例患者的46个外伤膝关节,行手术治疗前均进行了多序列的MRI,包括膝关节常规MRI(SE T1WI,FSE PD/T2WI),3D SPGR和3D FIESTA序列.运用改良的Noyes分类系统来评价膝关节软骨面的损伤等级,每个膝关节的关节面包括:股骨外侧髁(LFC)、股骨内侧髁(MFC)、胫骨外侧平台(LTP)、胫骨内侧平台(MTP)、股骨滑车(Trochlea)和髌骨(Patella).以手术结果为"金标准",比较各序列发现软骨损伤的敏感性、特异性、准确性、阳性及阴性预测值.用Wilson评分法计算敏感性和特异性的95%可信区间,用McNemar统计法的双尾精确表来比较不同MRI序列对软骨分级诊断的显著性差异.结果 根据手术结果,软骨形态改变的发生率为43%(118/276),软骨缺损的发生率为23%(63/276).各个关节面软骨损伤的发生率无明显差异.MR图像(3D SPGR、3D FIESTA、3D SPGR结合常规MRI)表现与手术结果的完全一致率分别为53%、60%和85%,之间差异无统计学意义.但是3D SPGR结合常规MRI序列评价软骨损伤的敏感性、特异性、阳性预测值和阴性预测值均为最高,分别为73%、98%、95%和90%.结论 3D SPGR和3D FIESTA序列在诊断膝关节软骨病变时无明显差异.3D SPGR结合常规MRI序列,不仅可以在合理的扫描时间内提高诊断软骨病变的准确性,而且还可对膝关节的其他组织结构做出全面的评价.     

1.5T MR研究健康人膝关节软骨T_2值空间分布

目的 研究健康成人膝关节软骨T2弛豫时间(T2值)空间分布.方法 1.5T场强下对21名健康男性(年龄24～39岁,平均30岁±4岁)行膝关节矢状位多回波多层面SE序列扫描,使用Profile软件测量股骨非承重软骨的前部、股骨承重软骨、胫骨承重软骨、髌软骨的T2弛豫时间(即T2值),采用方差分析检验各部位软骨深层和浅层T2值、承重软骨和非承重软骨的T2值空间分布的差异.结果 健康人膝关节软骨T2值空间分布呈浅凹形曲线,即近软骨下骨质T2值较高,随后T2值从软骨深层到浅层逐渐增高,并且各层T2值存在差异(F=70.892,P＜0.05).髌软骨T2值空间分布变化最大,股胫关节承重软骨和股骨前部非承重软骨T2值的空间分布变化较平缓.髌软骨深层T2值[(26.56±4.4) ms]明显低于所有软骨深层T2值(P=0.001).股骨外髁承重软骨浅层T2值[(35.2±6.31) ms]明显低于髌软骨[(40.78±3.56) ms]和股骨非承重软骨前部[(42.31±2.4) ms](P=0.002,P=0.000).胫骨外髁承重部软骨浅层T2值[37.11±6.6) ms]明显低于股骨非承重前部(P=0.000).结论 1.5T 场强下健康人膝关节软骨T2值具有特定空间分布,对量化研究退行性骨关节炎和其他关节病变具有参考价值.     

Determination of 3D cartilage thickness data from MR imaging: computational method and reproducibility in the living.

The objective of this work was to develop a computational approach for quantifying the three-dimensional (3D) thickness distribution of articular cartilage with magnetic resonance (MR) imaging, independent of the imaging plane, and to test the reproducibility of the method in the living. An algorithm was implemented, based on a 3D Euclidean distance transformation, and its accuracy was assessed in geometric test objects, for which an analytic solution was available. The precision of the method was evaluated in six replicated MR data sets of the knee joint cartilage of eight volunteers. The algorithm produced 3D thickness values identical to those of the analytic solutions in the test objects. The reproducibility of the mean cartilage thickness in the patellar and tibial cartilages was 1.5-3.4% (root-mean-square average of the individual coefficient of variation percent), that of the maximal thickness 2.1-7.9%, and that of the thickness distribution 2.3-6.1%. The method presented allows for noninvasive analysis of 3D cartilage thickness from MR images in biomechanical and clinical investigations.     

Preliminary trial of three-dimensional water-excitation magnetization transfer contrast MR imaging of articular cartilage]

MR images of articular cartilage were evaluated with a three-dimensional (3D) water-excitation sequence (repetition time/echo time/flip angle = 28 msec/14 msec/20 degrees) with and without on-resonance magnetization transfer contrast (MTC) pulse in-vitro and in-vivo. 3D water-excitation images with MTC pulse showed a significantly higher contrast-to-noise ratio between normal saline or joint effusion and articular cartilage than images without MTC pulse. In 2 patients with osteoarthritis of the knee, joint effusion showed higher signal intensity than cartilage (arthrogram-like effect) on 3D water-excitation MTC images. The contrast between joint effusion and articular cartilage on 3D water-excitation MTC images was similar to that on fat-suppressed 2D protondensity-weighted fast spin echo images. In conclusion, 3D water-excitation MTC imaging is a promising method by which to evaluate articular cartilage in osteoarthritis and cartilage defect with thin sections and a reasonable scan time.     

Articular cartilage of the knee: evaluation with fluctuating equilibrium MR imaging--initial experience in healthy volunteers

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study, whose purpose was to prospectively compare three magnetic resonance (MR) imaging techniques-fluctuating equilibrium, three-dimensional (3D) spoiled gradient-recalled acquisition in the steady state (SPGR), and two-dimensional (2D) fast spin echo (SE)-for evaluating articular cartilage in the knee. The study cohort consisted of 10 healthy volunteers (four men, six women; age range, 26-42 years). Cartilage signal-to-noise ratio (SNR), SNR efficiency, cartilage-fluid contrast-to-noise ratio (CNR), CNR efficiency, image quality, cartilage visibility, and fat suppression were compared. Cartilage volume was compared for the fluctuating equilibrium and 3D SPGR techniques. Compared with 3D SPGR and 2D fast SE, fluctuating equilibrium yielded the highest cartilage SNR efficiency and cartilage-fluid CNR efficiency (P < .01 for both). Image quality was similar with all sequences. Fluctuating equilibrium imaging yielded higher cartilage visibility than did 2D fast SE imaging (P <. 01) but worse fat suppression than did 3D SPGR and 2D fast SE imaging (P < .04). Cartilage volume measurements with fluctuating equilibrium and 3D SPGR were similar. Fluctuating equilibrium MR imaging is a promising method for evaluating articular cartilage in the knee.     

Diagnosis of articular cartilage abnormalities of the knee: prospective clinical evaluation of a 3D water-excitation true FISP sequence

PURPOSE: To prospectively evaluate the accuracy of three-dimensional (3D) water-excitation true fast imaging with steady-state precession (FISP) in the assessment of cartilage abnormalities of the knee, by using surgery as the reference standard. MATERIALS AND METHODS: The study was approved by the hospital institutional review board. Written informed consent was obtained from all patients. Twenty-nine patients (30 knees) with a mean age of 56 years (range, 18-86 years) were prospectively evaluated with a sagittal 3D true FISP magnetic resonance (MR) sequence. The mean interval between MR imaging and surgery was 1 day (range, 0-9 days). During surgery, the articular surfaces of the knee were evaluated by using a modified Noyes score. The MR images were evaluated by two blinded readers on two separate occasions. Diagnostic performance was evaluated by setting the cutoff for abnormality between grade 1 (intact cartilage surface) and grade 2 (cartilage defects). Statistical methods used included calculation of sensitivity, specificity, and accuracy, with 95% confidence intervals (Wilson score method) and calculation of kappa values with standard errors. RESULTS: Overall sensitivity, specificity, and accuracy for the two readers and the two evaluations ranged from 56% to 66%, 78% to 93%, and 71% to 75%, respectively. Interobserver agreement was substantial for both the first (kappa = 0.73) and the second (kappa = 0.65) evaluation. Intraobserver agreement was almost perfect (kappa = 0.84) for reader 1 and moderate (kappa = 0.60) for reader 2. CONCLUSION: The 3D water-excitation true FISP MR sequence allows assessment of the articular cartilage of the knee with moderate-to-high specificity and low-to-moderate sensitivity.     

Selective water excitation for faster MR imaging of articular cartilage defects: initial clinical results

Our objective was to compare a water-excitation (WE) 3D fast low-angle shot (FLASH) MR sequence for faster imaging of articular cartilage defects of the knee to a conventional fat-saturated (FS) 3D FLASH MR sequence. This prospective study included 16 knees of 16 patients with suspected cartilage lesions. The MR imaging in transverse and sagittal planes included (a) FS 3D FLASH (TR/TE: 45 ms/11 ms, scan time 8 min, flip angle 50°), and (b) WE 3D FLASH (TR/TE: 28 ms/11 ms, scan time 4 min 58 s, flip angle 40°). For each sequence signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were quantified. The detected cartilage lesions were evaluated using a semi-quantitative four-scale scoring system (grades 0–III). The data were compared between the sequences using the paired Student's t-test. No statistically significant differences between the sequences were found for SNR, CNR, and cartilage defect grading (p=0.14–0.8). The WE 3D FLASH MR imaging seems to be promising for fast imaging of articular cartilage lesions of the knee. Electronic Publication     

Width of the articular cartilage of the hip: quantification by using fat-suppression spin-echo MR imaging in cadavers.

OBJECTIVE. Use of MR imaging to measure the width of the articular cartilage has not been thoroughly investigated. The value of a selective fat-suppression spin-echo sequence in the quantitative assessment of articular cartilage of the hip was studied in cadavers. MATERIALS AND METHODS. Sagittal and coronal images were acquired in 10 cadaveric hips (age range at time of death, 62-81 years). On the coronal and sagittal MR images that were closest to the center of the femoral head, marks were placed every 30 degrees, with the midpoint of the femoral head used as a reference. Cartilage thickness was measured in 123 resulting locations. Sixty-three positions included both femoral and acetabular cartilages, and 60 positions included femoral cartilage without an acetabular counterpart. The findings were compared with corresponding anatomic sections. RESULTS. For the 60 locations containing only femoral cartilage, significant correlation between MR and anatomic sections was found (Pearson correlation coefficient = .34, p = .0089). Of the 63 locations containing both femoral and acetabular cartilages, the two cartilage layers could be differentiated on the MR images in 50 locations. In these 50, the MR and anatomic measurements of the femoral cartilage correlated significant (r = .58, p less than or equal to .0001). Measurements of the acetabular cartilage in these 50 locations yielded no significant correlation (r = .25, p = .08). When the entire cartilage (femoral plus acetabular) was measured in all 63 locations, the correlation between MR and anatomic measurements was .29 (p = .02). The correlation coefficients obtained in this investigation indicate considerable scattering of the data. CONCLUSION. Our results show that measurements of articular cartilage thickness of the hip on fat-suppression spin-echo MR images are not sufficiently accurate to be of clinical value.     

Evaluation of grades 3 and 4 chondromalacia of the knee using T2*-weighted 3D gradient-echo articular cartilage imaging

Objective. To determine the accuracy of T2*-weighted three-dimensional (3D) gradient-echo articular cartilage imaging in the identification of grades 3 and 4 chondromalacia of the knee. Design and patients. A retrospective evaluation of 80 patients who underwent both arthroscopic and MRI evaluation was performed. The 3D images were interpreted by one observer without knowledge of the surgical results. The medial and lateral femoral condyles, the medial and lateral tibial plateau, the patellar cartilage and trochlear groove were evaluated. MR cartilage images were considered positive if focal reduction of cartilage thickness was present (grade 3 chondromalacia) or if complete loss of cartilage was present (grade 4 chondromalacia). Comparison of the 3D MR results with the arthroscopic findings was performed. Results. Eighty patients were included in the study group. A total of 480 articular cartilage sites were evaluated with MRI and arthroscopy. Results of MR identification of grades 3 and 4 chondromalacia, all sites combined, were: sensitivity 83%, specificity 97%, false negative rate 17%, false positive rate 3%, positive predictive value 87%, negative predictive value 95%, overall accuracy 93%. Conclusion. The results demonstrate that T2*-weighted 3D gradient-echo articular cartilage imaging can identify grades 3 and 4 chondromalacia of the knee. Received: 18 April 2000 Revision requested: 18 July 2000 Revision received: 10 October 2000 Accepted: 27 November 2000