膝关节软骨MR成像的技术探讨

目的探讨膝关节软骨MR I成像技术和三维(3D)软骨重建的方法,为临床早期诊断和治疗方法提供了有效的评估方法。方法对90例膝关节外伤、关节炎性病变患者和10例健康志愿者进行MR I扫描,采取常规和特殊的二维(2D)、3D多序列,多参数的比较。对3D快速梯度回波扫描序列获得膝关节各关节软骨3D图像,利用最大信号强度投影法(M IP)进行3D重建。对各关节软骨的平均厚度的测量值进行统计学分析。结果膝关节软骨MR I成像技术和3D软骨重建的方法,可以清晰显示膝关节各关节软骨的结构,在2D FSE序列上关节软骨约50%均显示为3层改变,在3D重建图像上,可清淅地多角度整体显示膝关节各关节软骨的结构,空间分辨率高。结论膝关节软骨MR I成像和3D软骨重建技术,为临床早期诊断和治疗方法提供帮助。     

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     

3T MRI关节软骨成像序列的比较和探讨

目的:通过分析比较各3T MRI关节软骨成像序列对关节软骨显示的能力与限度,探讨理想的3T MRI关节软骨成像序列组合.方法:收集因临床需要而检查的36例膝关节MRI,成像设备为SIEMENS3.0T VERIO高场MRI,关节软骨成像序列包括:自旋回波序列(SE),二维脂肪抑制质子密度加权像(FS-PD),二维短T1翻转恢复序列(2D-STIR),三维双重回波稳态(3D-DESS),三维平衡稳态序列(3D-True FISP)和关节软骨生理成像T2mapping.在股骨髁间凹中央层面上分别测量股骨髁软骨信号噪声比(SNR)、软骨-关节液对比度噪声比(CNR),比较各序列对于软骨和周围关节液的显示能力.结果:3D-DESS,3D-True FISP和FS-PD序列软骨SNR最高(P<0.001);同时3D-DESS,3D-True FISP和FS-PD序列软骨-关节液对比度噪声比(CNR)高于2D-STIR,但软骨-关节液边界对比以3D-DESS序列最好,能显示关节软骨水含量变化的只有T2mapping成像.结论:二维脂肪抑制质子密度加权像(FS-PD)加上三维双重回波稳态(3D-DESS)是进行软骨MRI的理想序列组合,T2mapping可以显示关节软骨含水量的变化.     

3T磁共振3D-FS-SPGR序列对膝关节软骨损伤的诊断价值

目的：以关节镜检查结果为标准,分析评价3.0T磁共振3D-FS-SPGR序列对膝关节软骨损伤的诊断价值。方法：对将要进行关节镜检查的50个膝关节进行磁共振多序列、多方位成像,包括矢状位FSE-T2WI、FSE-T1WI、FS-FSE-T2WI、3D-FS-SPGR序列及冠状位、轴位FS-FSE-T2WI序列。利用矢状位3D-FS-SPGR序列图像重建出冠状位及轴位图像。将磁共振检查结果与随后进行的关节镜检查结果进行对照。在MRI上对股骨内外侧髁、胫骨内外侧平台、股骨滑车及髌骨六个关节面关节软骨（共300处）进行评价。另外选取10名志愿者20个膝关节作为对照组进行MR成像,成像序列同患者组。结果：①在FS-FSE-T2WI序列上正常膝关节软骨为光滑的曲线状高信号带,在股骨内、外髁及胫骨平台表面关节软骨呈由表及里的高、低、高3层结构;FSE-T2WI及FSE-T1WI上关节软骨分层现象不明显呈中低信号;在3D-FS-SPGR序列上关节软骨呈明显带状高信号并呈由表及里的高、低、高3层结构;②软骨I级损伤在FS-FSE-T2WI上表现为低或高信号,在3D-FS-SPGR序列上表现为低信号,软骨分层现象消失;软骨缺损（II~IV级损伤）在FSE-T1WI上呈等信号,在FSE-T2WI及FS-FSE-T2WI上表现为高信号,在3D-FS-SPGR上表现为低信号;③3D-FS-SPGR序列对软骨损伤显示的敏感度为91.4%,特异度为95.9%,Kappa值为0.808（〉0.75）;FS-FSE-T2WI序列的敏感度为88.9%,特异度为96.8%,Kappa值为0.774（〉0.75）;FSE-T2WI序列的敏感度为75.3%,特异度为98.2%,Kappa值为0.548;FSE-T1WI序列的敏感度为64.2%,特异度为99.1%,Kappa值为0.444。结论：①FSE-T2WI、FSE-T1WI、FS-FSE-T2WI、3D-FS-SPGR序列均可以很好的显示膝关节软骨,以3D-FS-SPGR序列显示的最清晰;②3D-FS-SPGR序列显示膝关节软骨损伤优于FSE-T2WI、FSE-T1WI、FS-FSE-T2WI序列,为诊断膝关节软骨损伤的最佳序列。     

10～20岁健康志愿者骶髂关节软骨MRI序列对照研究

目的 研究10～20岁健康志愿者骶髂关节软骨的正常MR表现,初步探讨MRI显示SIJ软骨的最佳序列. 资料与方法 随机选择30名10～20岁无骶髂关节疾病的健康志愿者作为研究对象,行T1WI快速自旋回波(TSE)、T1WI频谱预饱和反转恢复(SPIR)、T2WI-TSE、T2WI-SPIR、T2WI快速场回波(FFE)、PROSET和三维水选择成像(3D-WATS)不同序列骶髂关节MR检查,观察骶髂关节软骨显示情况,利用双盲法对各序列图像进行评价,并与尸体标本进行对照. 结果 T1WI-TSE、T1WI -SPIR、T2WI-TSE、T2WI-SPIR序列只能显示出软骨信号,无法分辨骶侧、髂侧软骨;T2WI-FFE 序列软骨显示清晰,41个可分辨骶侧、髂侧软骨;3D-WATS、PROSET序列关节软骨更清晰,能区分开骶侧软骨和髂侧软骨,分别为56个和48个,但二者之间差异无统计学意义.尸体标本骶髂关节的3D-WATS图像与健康志愿者的表现基本一致. 结论 3D-WATS和PROSET序列是显示骶髂关节软骨较好的MR成像方法,可以区分骶侧软骨、髂侧软骨和二者之间的间隙.     

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。     

超短TE MRI对深部软骨的评估（25例尸体髌软骨MRI和组织学对比研究）

目的：利用超短TE成像技术对常规MR成像序列难以显示的深部关节软骨进行定性和定量研究。方法：用装有超短TE软件的1．5T MR机对25例尸体髌软骨标本进行MR扫描，扫描序列包括标准T1WI、脂肪抑制PdWI序列、超短TE成像（TE80ms）。将所有标本均连续切成3mm层厚断面并对每个断面进行大体和组织学分析。     

磁共振膝关节软骨形态表现的组织学相关性研究

目的：对照膝关节软骨磁共振和组织学表现，分析不同磁共振序列反映关节软骨厚度和组织学分层的能力与限度。材料和方法：分别对12例新鲜离体人膝关节标本采用以下序列行软骨磁共振成像：①SE T1加权序列；②FSE T2加权序列；③STIR序列；④3D—FS—SPGR序列；⑤FS—PD序列；⑥T2^＊加权GRE序列。选取各序列图像髁间凹中央层面髌软骨最厚区域为感兴趣区，测定软骨厚度及各分层大致厚度。成像后在标本相应部位取材以获得深及软骨下骨的软骨组织并行甲苯胺蓝染色。光镜下测定软骨厚度各组织层次厚度。对MR和组织学测定的参数进行对照分析。结果：①不同MR序列所显示的髌软骨厚度差异明显（F=36．470，P=0．041）；②FS—PD、FS—SPGR和T2^＊GRE所测软骨厚度与组织学测量值之间无显著差异（P=1．432，0．097，0．064），以FS—PD序列显示的髌软骨厚度值的组织学相关性最高（r=0．787）；③MR与组织学检查所显示的关节软骨层次之间具有显著性差异，两者的软骨层次厚度之间存在显著性差异（χ^2=13．12，P=0．012）；两者之间无相关性（P值均小于0．05）。结论：MR成像技术能精确反映关节软骨整体厚度变化；但MR软骨分层表现受多种因素共同影响，与组织学层次之间无相关性。     

3 T MRI关节软骨生化成分成像的研究进展

近年来,3 T MRI技术发展十分迅速,已广泛应用于软骨病变的诊断和疗效评价。各种软骨成像序列不断被开发和应用,目前已从传统的二维、三维形态成像向生化成分成像转变,以期能够对关节软骨形态学改变之前的软骨生化改变进行显示,为早期软骨损伤诊断和监测提供临床参考依据。目前,关节软骨生化成分成像技术包括T2mapping、T2＊mapping及T1ρ成像等。就3 T MR关节软骨生化成分成像的临床应用及研究进展予以综述。     

膝关节关节软骨损伤的MRI评价

目的:以关节镜为标准,评价不同MR成像序列(T2WI、T1WI及FS T2WI)对膝关节软骨损伤的诊断价值.方法:回顾性分析经关节镜证实的60例(60个)膝关节的MRI资料,MRI包括矢状位T2WI、T1WI及FS T2WI,冠状位FS T2WI,部分病人还行轴位FS T2WI.MRI图像对股骨内外髁、胫骨内外平台、股骨滑车及髌骨六个关节面关节软骨(共360处)进行评价,并与关节镜图像逐一对照.结果:①在FS T2WI上正常膝关节软骨为光滑的曲线状高信号带,在股骨内、外髁及胫骨平台表面关节软骨呈由表及里的高、低、高3层结构;T2WI及T1WI上关节软骨分层现象不明显呈中低信号;②与关节镜对照,60个膝关节软骨损伤患者的MRI检查结果:FS T2WI的敏感度为90.2%,特异度为96.6%,Kappa值为0.766;T2WI的敏感度为80.5%,特异度为98.5%,Kappa值为0.537;T1WI的敏感度为63.0%,特异度为99.3%,Kappa值为0.367.结论:FS T2WI序列显示膝关节软骨损伤的准确性优于T2WI和T1WI序列并与关节镜诊断结果之间具有良好的一致性.T2WI、T1WI及FS T2WI三序列在诊断膝关节软骨损伤的准确性方面有显著差性异.     

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.     

Reduction of truncation artifacts in rapid 3D articular cartilage imaging

PURPOSE: To reduce Gibbs ringing artifact in three-dimensional (3D) articular knee cartilage imaging with linear prediction (LP). MATERIALS AND METHODS: A reconstruction method using LP in 3D was applied to truncated data sets of six healthy knees. The technique first linearizes the data before applying the prediction algorithm. Three radiologists blindly reviewed and ranked images of the full, truncated, and predicted data sets. Statistical analysis of the radiologists' reviews was performed for image quality, clinical acceptability of the images, and equivalence with the gold standard. RESULTS: LP applied to 3D knee cartilage imaging allows for 40% decreased scan time while providing image quality with statistical equivalence to a full data set. CONCLUSION: 3D spoiled gradient echo imaging (SPGR) knee cartilage imaging requires significant scan time. This 40% reduction in scan time will allow such scans to be more feasible without sacrificing clinical acceptability.     

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.     

Imaging of the articular cartilage in osteoarthritis of the knee joint: 3D spatial-spectral spoiled gradient-echo vs. fat-suppressed 3D spoiled gradient-echo MR imaging

PURPOSE: To compare three-dimensional (3D) spatial-spectral (SS) spoiled gradient-recalled acquisition in the steady state (SPGR) imaging with fat-suppressed 3D SPGR sequences in MR imaging of articular cartilage of the knee joint in patients with osteoarthritis. MATERIALS AND METHODS: MR images of six patients with osteoarthritis of the knee were prospectively examined with a 1.5T MR scanner. For quantitative analyses, the signal-to-noise ratios, contrast-to-noise ratios, and contrast of cartilage and adjacent structures including meniscus, synovial fluid, muscle, fat tissue, and bone marrow were measured. RESULTS: In patients with osteoarthritis, 3DSS-SPGR images demonstrated higher spatial resolution and higher mean signal-to-noise (S/N) ratios (cartilage, 24.9; synovial fluid, 12.3; muscle, 20.7; meniscus, 21.6), with shorter acquisition times (7 minutes 20 seconds), when compared to fat-suppressed 3D SPGR images (cartilage, 22.3; synovial fluid, 10.8; muscle, 16.7; meniscus, 13.4). CONCLUSION: 3DSS-SPGR imaging is a promising method for evaluating cartilage pathology in patients with osteoarthritis of the knee and has the potential to replace fat-suppressed 3D SPGR imaging.     

Articular cartilage of knee: normal patterns at MR imaging that mimic disease in healthy subjects and patients with osteoarthritis

PURPOSE: To evaluate normal magnetic resonance (MR) imaging findings that may mimic articular cartilage diseases in healthy subjects and patients with osteoarthritis of the knee. MATERIALS AND METHODS: Sagittal fat-suppressed intermediate-weighted fast spin-echo (FSE) (repetition time msec/echo time [TE] msec, 4,000/13), sagittal T2-weighted FSE (4,000/39), and sagittal fat-suppressed three-dimensional (3D) spoiled gradient-echo (SPGR) (60/5, 40 degrees flip angle) MR images were acquired in 28 patients and four volunteers. FSE images with a TE of 13 msec were considered "short-TE images"; those with a TE of 39 msec were considered "long-TE images." Presence of normal MR imaging appearance of articular cartilage was determined by one author. Contrast between cartilage and adjacent structures (meniscus, joint capsule, synovial fluid, muscle) was calculated in posterior regions of the femoral condyle on images obtained with each sequence; Wilcoxon signed rank testing was performed. RESULTS: The following appearances were observed in patients with knee osteoarthritis (on short-TE FSE, long-TE FSE, and SPGR MR images, respectively): (a) ambiguity of surface contour in posterior region of the femoral condylar cartilage (in zero, zero, and 20 patients), (b) linear area of high signal intensity in deep zone adjacent to subchondral bone of femoral condyle (in zero, zero, and 26 patients), (c) pseudolaminar appearance in posterior region of femoral condylar cartilage (in seven, nine, and 24 patients), (d) truncation artifact in patellofemoral compartment (in seven, six, and 27 patients), (e) susceptibility artifact on cartilage surface caused by air or metal (in three, three, and 11 patients), (f) decreased signal intensity in distal part of trochlear cartilage (in 28, 28, and 28 patients), (g) cartilage thinning adjacent to the anterior horn of the lateral meniscus (in 19, 19, and 21 patients), and (h) focal cartilage flattening in posterior region of femoral condyle (in 16, 16, and nine patients). Cartilage-meniscus and cartilage-synovial fluid contrast was significantly higher on fat-suppressed FSE than on fat-suppressed 3D SPGR MR images (P <.001). CONCLUSION: Fat-suppressed FSE and 3D SPGR MR images showed nonuniform signal intensity arising from articular cartilage and cartilage thinning, both of which could mimic disease.     

Advanced morphological and biochemical magnetic resonance imaging of cartilage repair procedures in the knee joint at 3 Tesla

Morphological and biochemical magnetic resonance imaging (MRI) is due to high field MR systems, advanced coil technology, and sophisticated sequence protocols capable of visualizing articular cartilage in vivo with high resolution in clinical applicable scan time. Several conventional two-dimensional (2D) and three-dimensional (3D) approaches show changes in cartilage structure. Furthermore newer isotropic 3D sequences show great promise in improving cartilage imaging and additionally in diagnosing surrounding pathologies within the knee joint. Functional MR approaches are additionally able to provide a specific measure of the composition of cartilage. Cartilage physiology and ultra-structure can be determined, changes in cartilage macromolecules can be detected, and cartilage repair tissue can thus be assessed and potentially differentiated. In cartilage defects and following nonsurgical and surgical cartilage repair, morphological MRI provides the basis for diagnosis and follow-up evaluation, whereas biochemical MRI provides a deeper insight into the composition of cartilage and cartilage repair tissue. A combination of both, together with clinical evaluation, may represent a desirable multimodal approach in the future, also available in routine clinical use.     

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     

Correlation of laminated MR appearance of articular cartilage with histology, ascertained by artificial landmarks on the cartilage.

The object of this study was to correlate the laminae of articular cartilage on magnetic resonance (MR) imaging with histologic layers. T1- and fast spin-echo T2-weighted images of articular cartilage with artificial landmarks were obtained under high gradient echo strength (25 mT/m) conditions and a voxel size of 78 x 156 x 2000 microm. Images were also obtained with a) changed frequency-encoding directions; b) changed readout gradient strength; and c) a varied number of phase-encoding steps. T2 mapping was performed with angular variations. Artificial landmarks allowed accurate comparison between the laminae on MR images and the histologic zones. No alterations of the laminae were noted by changing the frequency gradient direction. Altering readout gradient strengths did not show a difference in the thickness of the laminae, and increasing the phase-encoding steps resulted in a more distinct laminated appearance, ruling out chemical shift, susceptibility, and truncation artifacts. The T2 mapping profile showed an anisotropic angular dependency from the magic angle effect. In conclusion, the laminated appearance of articular cartilage on spin-echo and fast spin-echo MR images correlated with the histologic zones rather than MR artifacts.