磁共振斜冠状位扫描对正常膝关节前交叉韧带的显示作用

目的 探讨磁共振斜冠状位扫描对膝关节前交叉韧带的显示价值.方法 对60例正常膝关节行常规扫描,包括斜矢状位、冠状位、横断位.所有病例均行在斜矢状位图像基础上平行于前交叉韧带FSE序列斜冠状位薄层无间隔质子密度加权扫描,分析斜冠状、斜矢状、冠状及横断位对前交叉韧带的显示情况.结果 斜冠状可清楚全程显示前交叉韧带于一幅图片上,显示率为100％(60/60),斜矢状位显示率为86.7％(52/60),而横断及冠状位则分段显示前交叉韧带,即不能在一幅图中完整显示前交叉韧带.结论 斜冠状位扫描符合前交叉韧带解剖走向,可明显提高前交叉韧带的完整显示率,有利于其损伤后评价.     

膝关节前交叉韧带MR扫描方式的研究

目的：探讨前交叉韧带MRI最佳的扫描方式,提高前交叉韧带MR图像的显示程度。方法：回顾性分析100例前交叉韧带MRI图像。每住受检者都按两种不同扫描方式进行扫描,第一组：斜矢状面以轴面定位像进行扫描;第二组：斜矢状面在第一组定位方式基础上,再在冠状面上按前交叉韧带走行倾斜角度进行扫描,观察两组前交叉韧带MR图像的显示情况,将所得前交叉韧带图像分为可全程显示、可分段显示、不显示三种,最后将统计出的数据进行分析。结果：第一种扫描方式全程显示70例（70／100）、分段显示25例（25／100）、不显示5例（5／100）;第二种扫描方式全程显示95例（95／100）、分段显示5例（5／100）、不显示0例（0／100）。结论：两种扫描方式前交叉韧带的显示程度差异有显著性意义（P〈0．01）,第二种扫描方式对前交叉韧带的显示情况良好,是一种较为理想的扫描方式,能显著提高前交叉韧带的显示率。     

磁共振膝关节斜冠状位扫描对前交叉韧带的评价

目的　探讨磁共振膝关节斜冠状位扫描对前交叉韧带的显示价值。方法　对 3 0例正常膝关节均行常规横断、斜矢状、冠状扫描 ,扫描序列还包括在斜矢状图像基础上行平行于前交叉韧带FSE序列斜冠状薄层无间隔T2 扫描 ,分析斜冠状、斜矢状及冠状位对正常前交叉韧带的显示情况。结果　正常膝关节于 1幅图片上可清楚显示ACL全程者 ,斜冠状显示率为 10 0 % (3 0 3 0 ) ,斜矢状位显示率为 83 .3 % (2 5 3 0 ) ,而冠状位前交叉韧带呈节段状 ,不能在 1幅图像中显示完整的ACL。结论　斜冠状位可在 1幅图像上完整显示前交叉韧带起止附着区及中间纤维束 ,有利于对前交叉韧带显示及损伤后的评价     

前交叉韧带斜矢状位MR成像研究

目的观察基于膝关节MR 2DT2WI+fs图像的重建图像对前交叉韧带显示效果,优化扫描程序。方法分析60例前交叉韧带MR检查图像,按检查方法分A、B、C三组进行观察分析。A组:常规扫描标准矢状位图像;B组:基于A组图像的斜矢状位重建图像;C组:斜矢状位扫描图像。观察三组图像对前交叉韧带的显示情况。将图像分二级进行评价:Ⅰ级为前交叉韧带1幅图像完整、清晰显示;Ⅱ级前交叉韧带1幅图像不能完整显示,需连续两幅或三幅图像才能完整显示;最后统计数据进行分析。结果 A组图像:Ⅰ级36例,占60%;Ⅱ级24例,占40%。B组图像:Ⅰ级56例,占93.3%;Ⅱ级4例,占6.7%。C组图像:Ⅰ级5 4例,占90%;Ⅱ级6例,占10%。经计算显示A、B两组图像具显著差异;A、C两组图像具显著差异;B、C两组图像无显著差异。结论基于前交叉韧带MR2DT2WI+fs图像的重建图像对其显示良好,建议膝关节磁共振检查时以标准矢状位扫描所得二维图像进行MPR重建观察,无须特意行斜矢状位扫描或三维成像扫描后重建,可以优化MR检查流程。     

膝关节前交叉韧带前内侧束和后外侧束的MR成像研究

目的 提高对膝关节前交叉韧带前内侧束和后外侧束的影像认识,并探讨其3.0T MR的理想常规成像显示平面.方法 回顾性分析149例正常膝关节的3.0TMR图像,采用x2分割法分析前交叉韧带、前内侧束和后外侧束双束结构及双束上、中、下各段在MR矢状面、冠状面、横断面各成像平面显示率的差异.结果 前交叉韧带前内侧束和后外侧束双束结构显示率,横断面(115/149,77.2％)与冠状面(103/149,69.1％)比较,×2=2.4606,P＞0.0125;横断面、冠状面分别与矢状面(21/149,14.1％)比较,x2值分别为119.5138、92.8695,P值均＜0.0125.前内侧束和后外侧束双束上段显示率,横断面( 104/149,69.8％)与冠状面(7/149,4.7％)、矢状面(0/149,0)及冠状面与矢状面分别比较,x2值分别为135.0813、159.7526、7.1684,P值均＜0.0125.前内侧束和后外侧束双束中段显示率,横断面(108/149,72.5％)与冠状面(94/149,63.1％)比较,x2=3.0120,P＞0.0125;横断面、冠状面分别与矢状面( 10/149,6.7％)比较,x2值分别为134.7454、104.2173,P值均＜0.0125.前内侧束和后外侧束双束下段显示率,横断面(103/149,69.1％)与冠状面(110/149,73.8％)比较,x2=0.8065,P＞0.0125;横断面、冠状面分别与矢状面(18/149,12.1％)比较,x2值分别为100.5300、115.9132,P值均＜0.0125.前交叉韧带双束各段在MRI各序列上均呈低信号,形态、走行正常.结论 3.0TMR常规扫描平面能够在一定程度上显示前交叉韧带的双束结构,横断面和冠状面是较为理想的显像平面.     

MR增强扫描诊断膝关节前交叉韧带部分撕裂

目的:评价MR增强扫描对膝关节前交叉韧带(ACL)部分撕裂的诊断价值。方法:回顾性分析有手术资料的56例患者的膝关节平扫加增强MR扫描图像,分析计算MRI对ACL部分撕裂的诊断价值。结果:MRI平扫诊断ACL 部分撕裂的诊断符合率、特异度、敏感度分别为73．2％、89．2％、82．1％;MRI平扫加增强扫描诊断ACL部分撕裂的诊断符合率、特异度、敏感度分别为91．1％、100％、82．1％。MR平扫加增强对诊断前交叉韧带部分撕裂的诊断符合率明显高于单纯MR平扫,差异有显著性意义(P<0．05);而两者间诊断特异度及敏感度的差异无显著性意义(P>0．05)。结论: 膝关节MR平扫加增强扫描对诊断ACL部分撕裂优于常规MRI扫描。     

MR薄层斜冠状面评估膝关节后外侧小结构的价值

【摘要】目的：探讨MR薄层斜冠状面评估正常膝后外侧小结构-腘腓韧带（PFL）、弓状韧带（Ar）及豆腓韧带（FFL）的价值,提高对相应结构的认识。方法：60名膝后外侧角（PLC）未损伤者行常规方位及薄层斜冠状位MR扫描,采用四分法评价不同方位显示PFL、Ar及FFL的价值,并分析毗邻的Ar与FFL两条韧带间是否存在相关性。结果：MR薄层斜冠状面显示PFL、FFL的评分均优于常规冠状面（P<0.05）,显示Ar的评分两种方位无明显差异（P>0.05）。薄层斜冠状面上PFL、FFL的显示率分别为87%（52/60）、35%（21/60）,表现为清晰连续的条状低信号。Ar的显示率分别为完全显示37%（22/60）、部分显示47%（28/60）、未显示16%（10/60）,Ar与FFL显示情况间呈负相关（rs=-0.417,P=0.001）。结论：MR薄层斜冠状面较常规冠状面更易于显示PFL及FFL,是用于更精确显示膝后外侧小结构的有效补充方位;毗邻的Ar与FFL因形态显示上密切相关,在共同维护PLC区稳定方面可能兼具功能相关性。     

前交叉韧带斜冠状面薄层解剖断面与MRI表现对照研究

目的对冰冻膝关节前交叉韧带（ACL）斜冠状面薄层解剖断面与正常人膝关节MRI特点进行对照研究，为ACL损伤分级诊断建立基础。方法1例（1只）膝关节标本行斜冠状面MRI确定角度，冰冻后沿斜冠状面1mm层厚铣切，观察ACL薄层解剖特点。选择50名正常人对其ACL进行MR斜冠状面扫描，观察ACL的MRI特点。结果1只膝关节标本的ACL在斜冠状面薄层断面清晰显示其全程走行，清晰地显示ACL前内束与后外束，前内束从股骨髁附着点后上方区自后向外侧及前内侧走行，止于髁间棘附着区前内侧方，后外侧束从股骨髁附着点前下方区，自后外侧及外下走行，止于髁间棘附着区后外侧方。斜冠状面MRI能够显示50名正常人ACL全程，显示率为100％。MRI能够区分ACL前内束与后外束结构，显示前内束自后外侧向前内走行，止于髁间棘附着区前内侧方，后外束自后外侧向外下走行，止于髁间棘附着区后外侧方。MRI显示ACL走行与薄层断面显示的走行一致。结论斜冠状面是观察ACL的最佳方位，临床对怀疑ACL损伤的患者必要时行MR斜冠状面扫描。     

高场磁共振对膝关节前交叉韧带损伤的诊断价值

目的研究高场磁共振（MR）对膝关节前交叉韧带损伤的诊断价值,为临床治疗提供可靠的依据。方法采用Siemens1．5T超导MR机,回顾性分析46例患者（前交叉韧带58例）的超导MR检查结果．分析前交叉韧带损伤的MR异常信号特点并观察前交叉韧带解剖学特点,与膝关节镜结果进行对比。结果58例前交叉韧带中,不全性撕裂32例,完全性撕裂26例。高场超导MR诊断前交叉韧带不全性撕裂和完全性撕裂与关节镜吻合率约为91％和100％。结论高场MR诊断膝关节前交叉韧带损伤的准确率高,能够为临床治疗提供很好的参考依据。     

MRI多征象分析对前交叉韧带损伤的诊断价值

目的：评价MRI对前交叉韧带（anterior cruciate ligament,ACL）损伤多种征象的诊断价值。方法：回顾分析了128个膝关节的MR图像。全部膝关节均行关节镜检查,其中52个膝关节的ACL损伤,另外76个膝关节的ACL显示完整。在不告知关节镜结果的前提条件下,2名影像科医生共同对ACL损伤的5个直接征象和10个间接征象进行评价,意见不一致时协商解决差异。结果：在评价的5个直接征象中,ACL不连续和ACL走行异常具有相对高的诊断敏感性和特异性;在评价的10个间接征象中,大多数具有相对高的特异性和低的敏感性,其中空髁间窝征、Notch征、外侧半月板后角裸露征、PCL指数、冠状面PCL单层显示等征象特异性较高。结论：ACL损伤的直接征象为诊断的主要依据,以ACL不连续和ACL走行异常具有较高的诊断价值;ACL损伤的间接征象具有辅助诊断意义,其中空髁间窝征、Notch征、外侧半月板后角裸露征、PCL指数、冠状面PCL单层显示等征象最具有诊断价值。     

MR imaging of the anterior cruciate ligament: value of thin slice direct oblique coronal technique

PURPOSE: The value of the thin slice direct oblique coronal technique, which is parallel to the anterior cruciate ligament (ACL), was assessed in the evaluation of ACL injury in comparison with conventional oblique sagittal and coronal images. MATERIAL AND METHODS: A thin slice direct oblique coronal technique was developed and applied clinically to 62 patients after conventional oblique sagittal and coronal images had been obtained. MR images of these 62 patients (24 with tears and 38 without tears) with an arthroscopic correlation were evaluated by three radiologists who were unaware of the arthroscopic results. The diagnostic accuracy of these new images was compared with that of oblique sagittal and coronal images by ROC analysis. RESULTS: Conventional oblique sagittal and coronal images for the diagnosis of ACL tears revealed accuracies of 82%, 84%, and 84%, sensitivities of 92%, 92%, and 96% and specificities of 76%, 79%, and 76% for the three reviewers, respectively. On thin slice direct oblique coronal images, specificities of 97%, 97%, and 97%, sensitivities of 96%, 96%, and 96%, and accuracies of 97%, 97%, and 97% were obtained, respectively. Diagnostic ability was significantly better with direct oblique coronal images (mean area under the ROC curve [Az]=0.99) than with conventional oblique sagittal and coronal images (Az=0.91) (p<0.05). CONCLUSION: The addition of thin slice direct oblique coronal images significantly improved specificity and accuracy in the diagnosis of ACL tears.     

MR imaging of anterior cruciate ligament repair

Magnetic resonance (MR) imaging is an accurate means of analyzing disruptions of the native anterior cruciate ligament (ACL). Various techniques may be used to repair a disrupted ACL. A common repair is the MacIntosh lateral-substitution over-the-top repair in which a strip of fascia lata from the iliotibial band is used as a "neoligament." The results of 27 MR examinations of 17 athletes with this repair were analyzed to determine the appearance of the neoligament on MR. Thirteen of the 17 patients had returned to full athletic activity and four were capable of strenuous activity. Examinations were made at both 0.5 and 1.5 T in varied extents of external rotation from 0 to 20 degrees, and at variable time intervals after surgery from 1 to nearly 40 months. Only two patients clinically required postrepair arthroscopy, but both had normal repairs. Neoligaments were classified as well-defined (n = 6 studies), ill-defined (n = 10), and not discernible (n = 11), based on clarity of appearance. Reasons for this variable appearance include the variable presence of fibrous and fatty tissue investing the neoligament. We conclude that the normal neoligament, unlike the normal active ACL, has a variable appearance, including nonvisualization on MR and that criteria used in evaluating the native ligament will be inadequate to assess the repair.     

Acute anterior cruciate ligament stump entrapment in anterior cruciate ligament tears: MR imaging appearance

PURPOSE: To describe the magnetic resonance (MR) imaging appearance of anterior cruciate ligament (ACL) stump entrapment in patients who presented with decreased knee extension after rupturing the ACL. MATERIALS AND METHODS: MR images in 15 patients who had presented with a block to terminal knee extension after sustaining an ACL tear were retrospectively reviewed. The MR imaging appearances of entrapped ACL stumps were defined and correlated with arthroscopic and histologic findings. RESULTS: The entrapped ACL stumps had two distinct appearances. Type 1 stumps (n = 11) were characterized by a nodular mass located at the anterior aspect of the intercondylar notch, interposed between the lateral femoral condyle and tibia. Type 2 stumps (n = 4) were characterized by a tonguelike free end and angulation of the stump. Histologic evaluation of the resected specimens showed distorted ACL fibers intermixed with variable fibrosis and inflammation. CONCLUSION: Entrapment of an ACL stump can limit knee extension. The two observed appearances of entrapped ACL stumps likely represent two points along a spectrum of appearances, which possibly includes the cyclops lesion.     

MR imaging of anterior cruciate ligament reconstruction graft

OBJECTIVE. The objective was to determine the MR imaging findings that differentiate intact anterior cruciate ligament reconstruction graft, partial-thickness tear, and full-thickness tear, using arthroscopy as the gold standard. MATERIALS AND METHODS. Sixteen consecutive MR imaging examinations were retrospectively and independently evaluated by two musculoskeletal radiologists for primary signs (graft signal, orientation, fiber continuity, complete discontinuity, and thickness) and secondary signs (anterior tibial translation, uncovered posterior horn lateral meniscus, posterior cruciate ligament hyperbuckling, and abnormal posterior cruciate ligament line) of anterior cruciate ligament reconstruction graft tear in 15 patients with follow-up arthroscopy. Results were compared with arthroscopy, and both receiver operating characteristic curves and kappa values for interobserver variability were calculated. RESULTS. Arthroscopy revealed four full-thickness graft tears, seven partial-thickness tears, and five intact grafts. Of the primary signs, graft fiber continuity in the coronal plane and 100% graft thickness in the sagittal or coronal plane were most valuable in excluding full-thickness tear. Complete discontinuous graft in the coronal plane also was valuable in diagnosis of full-thickness tear. Of the secondary signs, anterior tibial translation and uncovered posterior horn lateral meniscus assisted in differentiating graft tear (partial or full thickness) from intact graft. The other primary and secondary signs were less valuable. Kappa values were highest for graft fiber continuity and graft discontinuity in the coronal plane. CONCLUSION. Full-thickness anterior cruciate ligament graft tear can be differentiated from partial-thickness tear or intact graft by evaluating for graft fiber continuity (coronal plane), complete graft discontinuity (coronal plane), and graft thickness (coronal or sagittal plane).     

膝关节MR不同成像方位对前交叉韧带撕裂的诊断价值

目的：探讨膝关节MR不同成像方位对前交叉韧带（anterior cruciate ligament,ACL）撕裂的诊断价值,重点探讨横断位T2WI对ACL显示及撕裂的诊断价值。方法：回顾性分析2005年10月～2007年7月间192例膝关节创伤患者MR扫描图像资料,由两位放射诊断医生分析横断位、斜矢状位及斜冠状位T2WI图像对ACL撕裂评价的准确性。结果：192例膝关节创伤患者中关节镜证实ACL损伤23例（n=23）。两名读片医生对ACL损伤评价准确性于横断位为91．7％和88．5％,斜矢状位为92．7％和93．8％,斜冠状位为95．8％和94．3％。三种成像方位对ACL损伤评价的准确性差别无统计学意义,两位读片医生读片一致性检验kappa值横断位、斜矢状位及斜冠状位分别为0．754、0．764和0．867。结论：ACL及其损伤能在T2WI横断位、斜矢状位及斜冠状位三种成像方位上清晰显示,其中横断位T2WI为膝关节扫描常规扫描方位,其价值应得到重视。     

Grading of anterior cruciate ligament injury. Diagnostic efficacy of oblique coronal magnetic resonance imaging of the knee

OBJECTIVE: This study was undertaken to evaluate the diagnostic efficacy of additional oblique coronal magnetic resonance (MR) imaging of the knee for the grading of anterior cruciate ligament (ACL) injury. METHODS: We retrospectively reviewed MR images of the knee in 169 patients. The MR examinations included routine sequences and oblique coronal T2-weighted images, which oriented in parallel to the course of the femoral intercondylar roof. Two independent readers evaluated the status of the ACL by routine knee MR imaging and then by additional oblique coronal imaging. The severity of the ACL injury was graded using a 4-point system from MR images, namely, intact, low-grade partial tear, high-grade partial tear, and complete tear, and results were compared with arthroscopic findings. Weighted kappa statistics were used to analyze the diagnostic accuracy of routine knee MR imaging with and without additional oblique coronal imaging. RESULTS: The weighted kappa scores (kappaws) were 0.752 (reader 1) and 0.784 (reader 2) by routine knee MR imaging only; with additional oblique coronal imaging, the kappaws increased to 0.809 (reader 1) and 0.843 (reader 2). Interobserver agreements for routine knee MR imaging and additional coronal imaging were considered to be "very good" (kappaw = 0.851, 0.868, respectively). CONCLUSION: Additional use of oblique coronal MR imaging of the knee improves diagnostic accuracy in the grading of ACL injury.