膝关节交叉韧带低场强MRI表现及其损伤诊断

目的 :研究膝关节正常交叉韧带MRI特点和交叉韧带损伤的的MRI表现。方法 :对 2 0 0例正常膝关节交叉韧带的MRI进行回顾性分析 ,对 2 5例临床可疑交叉韧带损伤患者的MRI资料和关节镜检查行对比研究。结果 :正常膝关节矢状位MRI上显示交叉韧带最佳 ,冠状位和横断位作为补充 ,交叉韧带损伤的MRI表现为韧带连续性中断、局灶性或弥漫性肿胀、信号强度增高及断端移位 ;以关节镜检查结果为标准 ,MRI诊断交叉韧带损伤的敏感度为 91.3 % ,特异度为 91.6% ,符合率为 91.4%。结论 :MRI多方位扫描是一种准确诊断交叉韧带损伤的方法 ,矢状位显示交叉韧带最佳。     

Magnetic Resonance Imaging of Cruciate Ligament Injuries of the Knee

The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are important stabilizers of the knee. These ligaments are commonly injured in sports and motor vehicle accidents. An accurate diagnosis of cruciate ligament injuries is vital in patient care. Magnetic resonance imaging (MRI) can diagnose cruciate ligament injuries with high accuracy. The imaging diagnosis should be based on primary signs, although the secondary signs are sometimes useful, particularly in chronic cases. The detection of associated injuries of other structures of the knee, including menisci, collateral ligaments, cartilage, and bone, are also important. Accurate interpretation of the MRI examination requires a meticulous MRI technique, knowledge of the imaging anatomy, and understanding of the lesion appearance. This pictorial essay reviews the MRI appearance of normal and injured cruciate ligaments. Mechanisms of injury, primary and secondary MRI signs, and associated abnormalities are discussed.     

膝关节损伤的MRI诊断及其临床价值

目的：研究膝关节损伤的MRI特点、病理基础、诊断价值及其临床意义。材料与方法：回顾性分析42例经手术病理证实的膝关节损伤的MRI资料。结果：42例膝关节损伤患者中，半月板撕裂34例，MRI表现为黑色的半月板内出现异常信号，其中延伸至关节面（26例）；“水桶把手”样撕裂（4例）；半月板变形缩小（4例）。前交叉韧带损伤28例，MRI表现为黑色条索状无信号韧带影中出现异常信号，呈不连续弯曲波浪状、斑片状或团块状。后交叉韧带损伤4例。其他改变：半月板囊肿4例，侧副韧带损伤18例，关节积液38例，骨折7例。结论：MRI对膝关节损伤的诊断具有重要的临床意义，可为制定正确的治疗方案提供客观而详细的依据。     

The meniscal roots: gross anatomic correlation with 3-T MRI findings

OBJECTIVE: The purpose of this article is to highlight the normal anatomic features of the meniscal roots on photographs of dissected cadaveric knee specimens and 3-T MR images. CONCLUSION: The meniscal roots, which are critical attachment sites of the medial and lateral menisci to the central tibial plateau, are well-visualized on intermediate-weighted, turbo spin-echo 3-T MRI and can be identified in proximity to the tibial insertions of the anterior and posterior cruciate ligaments.     

膝关节韧带损伤的MRI诊断

目的:探讨膝关节韧带损伤的MRI表现及诊断价值。方法:36例临床怀疑膝关节损伤的患者于关节镜及手术前行MRI检查,以关节镜结果作为金标准,前瞻性分析膝关节韧带损伤的MRI表现及诊断价值。结果:关节镜证实前交叉韧带损伤21例,其中完全撕裂15例,部分撕裂6例,后交叉韧带损伤12例,正常患者15例。MRI诊断前交叉韧带损伤的敏感度为95.2%,特异度为80%,准确度为88.9%;诊断后交叉韧带损伤的敏感度为100%,特异度为95.8%,准确度为97.2%。结论:MR1是诊断膝关节韧带损伤的理想检查方法,具有较高的临床应用价值。     

The prevalence and significance of cyst-like changes at the cruciate ligament attachments in the knee

Approximately 1% of the total population referred for magnetic resonance imaging (MRI) of the knee at our facility have cystic changes at or near the attachment of the anterior or posterior cruciate ligaments (ACL, PCL). Cases were collected prospectively from a group of 1710 consecutive knee MR examinations, and a retrospective study analyzed the typical appearance of these cysts and any associated findings. Although most of the cysts were an incidental finding, two were associated with significant adjacent marrow edema.     

O'Donoghue's triad: magnetic resonance imaging evidence

Objective The objective was to search for magnetic resonance imaging evidence of medial collateral ligament (MCL) injury in knees with proven tears of the anterior cruciate ligament (ACL) and medial meniscus; the three abnormalities that make up O'Donoghue's triad. Although the MCL injury can be unapparent clinically, knee joint stability may be compromised. Design The superficial portion of the MCL was evaluated on 19 MR studies of 16 knees with arthroscopically proven ACL and medial meniscal tears. MCL thicknesses were compared to those on MR images of 19 normal knees. Patients The injured knees were of 13 men and 3 women, ranging in age from 19 to 56 years; the normal knees were of 10 men and 9 women, ranging in age from 19 to 55 years. Results and conclusions The medial collateral ligaments of all injured knees were abnormal, and, as a group, they had greater thicknesses and more intraligamentous thickness variability than normal knees. The MR appearance of both ACL and medial meniscal tears served as indirect evidence of MCL injury, with irregular MCL thickening indicative of prior injury.     

Mucoid degeneration of the anterior cruciate ligament mistaken for ligamentous tears

Objective. To describe the MR features of mucoid degeneration of the anterior cruciate ligament (ACL) in a series of patients with MRI findings that were mistaken for tears in the majority of cases but who were found to have an intact ligament at arthroscopy. We will suggest a pathologic entity corresponding to this finding and describe some characteristic features that can be used to identify this entity on MRI. Design. A retrospective analysis of 10 MRI examinations of the knee was performed after arthroscopic evaluation. Prearthroscopic MRI findings had been interpreted as a tear in six patients prospectively and in the remaining four the diagnosis of mucoid degeneration was suggested and ultimately proven. All patients had an intact ACL by preoperative clinical examination, examination under anesthesia, and at arthroscopy. Results. MRI examinations demonstrated an ill-defined ACL, greater in girth than the normal ligament and characterized by increased signal on all sequences. The high-signal ligament was oriented in the normal direction of the ACL. The overall appearance of the ligament was retrospectively described as like a celery stalk. Arthroscopy demonstrated mechanically intact ligaments with a normal to expanded external appearance. Probing of three of the ligaments caused a material to be expressed and pathologic evaluation resulted in the diagnosis of cystic, mucoid degeneration. Conclusion. Mucoid degeneration and an intact ACL can be suspected when an apparently thickened and ill-defined ligament with increased signal intensity on all sequences is identified in a patient with a clinically intact ligament. Received: 10 April 2000 Revision requested: 18 July 2000 Revision received: 13 November 2000 Accepted: 27 November 2000     

Does marathon running cause acute lesions of the knee? Evaluation with magnetic resonance imaging

An investigation was conducted into whether running a marathon causes acute alterations in menisci, cartilage, bone marrow, ligaments, or joint effusions, which could be evaluated by magnetic resonance imaging (MRI). Twenty-two non-professional marathon runners underwent MRI of the knee before and immediately after running a marathon. Lesions of menisci and cartilage (five-point scale), bone marrow, ligaments (three-point scale), joint effusion, and additional findings were evaluated and a total score was assessed. Before the marathon, grade 1 lesions of the menisci were found in eight runners, and grade 2 lesions in five runners. After the marathon, an upgrading from a meniscal lesion grade 1 to grade 2 was observed in one runner. Before the marathon, grade 1 cartilage lesions were found in three runners, and grade 2 lesions in one runner, all of which remained unchanged after the marathon. Before and after the marathon, unchanged bone marrow edema was present in three runners and unchanged anterior cruciate ligament lesions (grade 1) were seen in two runners. Joint effusions were present in 13 runners in the pre-run scans, slightly increased in four runners after the marathon, and newly occurred in one runner after the marathon. A total score comprising all knee lesions in each runner showed an increase after the marathon in two runners, whereas no runner showed an improvement of the radiological findings (Wilcoxon signed-rank test, P>0.05). The evaluation of lesions of the knee with MRI shows that marathon running does not cause severe, acute lesions of cartilage, ligaments, or bone marrow of the knee in well-trained runners. Only subtle changes, such as joint effusions or increased intrameniscal signal alterations, were imaged after running a marathon.     

膝关节损伤的MR应用价值

目的 :分析膝关节损伤的MR表现并评价其应用价值。方法 :选择 60例经临床或手术证实的膝关节损伤患者 ,回顾性分析、总结其MR表现。采用 1 .0TMR扫描机 ,常规应用矢状位 ,SET1 W、T2 W ,冠状位T1 W、T2 W成像。结果 :2 9例半月板损伤 ,其中Ⅰ° 1 0例 ,Ⅱ°1 2例 ,Ⅲ°7例 ;前交叉韧带损伤 1 8例 ,撕裂 2 2例 ;后交叉韧带损伤 7例 ,撕裂1例 ;内侧侧副韧带损伤 2 8例 ,撕裂 1 7例 ;外侧侧副韧带损伤 1 2例 ,撕裂 9例 ;韧带损伤表现为韧带不同程度增粗 ,但韧带连续性仍然存在 ,正常低信号内出现不规则高信号影 ,韧带撕裂表现为韧带明显增粗 ,呈弥漫性高信号 ,韧带的连续性部分或完全中断 ;股骨下端或胫骨上端骨质损伤 9例 ;关节积液 54例 ;多种损伤可同时出现。结论 :MR检查可很好显示膝关节损伤的各种表现 ,可作为膝关节损伤检查的重要或首选手段     

膝关节退行性骨关节病的MRI表现

目的 :探讨MRI对膝关节退行性骨关节病的诊断价值。方法 :对手术、关节镜或临床证实的 2 1例 2 6个膝关节退行性骨关节病的MRI表现进行回顾性分析。结果 :MRI能较好地显示膝关节病变的关节软骨、半月板、韧带、骨质等改变 ,还能对关节软骨、半月板损伤和退变进行分级 ,明显优于传统X线检查。结论 :MRI检查能清楚显示退行性骨关节病的病变特点和严重程度 ,为临床选择合适的治疗方案提供了依据。     

Health technology assessment of magnetic resonance imaging of the knee

A search of the available literature was performed and the role of MR imaging of the knee is discussed. Based on this search the authors concluded that MR has a high sensitivity in detecting any abnormalities in the knee but it does not have the same diagnostic accuracy as a clinical investigation performed by a trained knee specialist when all knee injuries are taken together. It does lead to a decrease in the number of surgical interventions due to its high negative predictive value. For the detection of meniscal injury, MR has the same accuracy as arthroscopy and should be performed in order to avoid unnecessary surgical interventions. A negative MR also obviates further investigation in suspected cartilage damage. This is not true for anterior and posterior cruciate ligament problems where MRI is less accurate than clinical investigation.     

Ganglion cysts of the cruciate ligaments

Purpose:
To evaluate the MR findings of ganglion cysts of the cruciate ligaments in correlation with clinical findings. Material and Methods:
We reviewed 12 patients with ganglion cysts of the cruciate ligaments obtained from a medical record of 4153 consecutive patients referred for knee MR examinations. All patients presented with chronic knee pain and 4 had restriction of knee motion. The MR imaging findings of the cysts were evaluated and correlated with clinical manifestations. Results:
Seven ganglion cysts were found in the posterior cruciate ligaments and 5 in the anterior cruciate ligaments. All cysts were lobulated (n=7) or fusiform (n=5) in shape, 1.8-4.5 cm in size, along the posterior surface in the proximal or distal end of the ligaments. Ten patients had arthroscopic resection or aspiration of their cysts, became symptom free and had no recurrence on follow-up MR examinations. Two cysts reduced in size spontaneously by conservative treatment. Conclusion:
MR imaging can offer useful information in detection and diagnosis of patients with chronic knee pain due to ganglion cysts of the cruciate ligaments. The size and location of the ganglion cysts can attribute to the clinical manifestations.     

Internal derangement of the knee after ipsilateral femoral shaft fracture: MR imaging findings

Objective. This study uses magnetic resonance (MR) imaging to delineate the types and frequencies of injuries seen in the knee after ipsilateral femoral shaft fracture. We also compare the results of the orthopedic knee examination with the MR findings. Design and patients. MR imaging of the ipsilateral knee was performed on 34 patients with closed femoral shaft fractures. Indications for knee MR imaging included knee pain at the time of fracture, soft tissue swelling or an effusion of the knee, or a positive knee examination under anesthesia. The patients had a mean age of 27 years and all were stabilized with intramedullary nails. Imaging was performed a mean time of 2.5 days after surgery. All patients had knee examinations done under anesthesia, and the MR results were compiled and compared with the clinical examinations. Results. Ninety-seven percent of patients demonstrated knee effusions. Twenty-seven percent of patients demonstrated meniscal tears, with the posterior horn of the medial meniscus most frequently torn. The medial collateral ligament was the most frequent site of ligamentous injury (38%) followed by the posterior cruciate ligament (21%). Fifty percent of patients had injuries of the extensor mechanism. Bone bruises were noted in 32% of patients. Articular cartilage injuries were confined to the patella in four cases. One occult tibial plateau fracture and one meniscocapsular separation were seen. Conclusions. There is a common incidence of both ligamentous and meniscal injury to the knee after ipsilateral femoral shaft fracture. MR imaging can be useful in assessing the extent of injury, and may reveal findings unsuspected after clinical examination of the knee.     

Value of the coronal plane in MRI of internal derangement of the knee

Sagittal images usually receive the most scrutiny in the magnetic resonance evaluation of meniscal and anterior cruciate ligament tears. We assessed the relative contribution of the coronal view. All knee magnetic resonance examinations performed over a 2-year period that had surgical confirmation were reviewed with respect to the presence of meniscal and anterior cruciate ligament tears. The appearance of an attenuated but uninterrupted anterior cruciate ligament was also evaluated. The coronal and sagittal plane images were evaluated separately. The study included 68 medial menisci, 67 lateral menisci, and 71 anterior cruciate ligaments. The coronal view is especially useful in the evaluation of the lateral meniscus. An anterior cruciate ligament that appears attennated but uninterrupted should be considered intact. The anterior cruciate ligament may be evaluated on the coronal view. The coronal view should be regarded as similar to the lateral chest radiograph, which supplements, but does not replace, the frontal chest radiograph.Presented at the Annual Meeting of the Radiological Society of North America, December 2, 1992, Chicago, Illinois     

Meniscofemoral ligaments: patterns of tears and pseudotears of the menisci using cadaveric and clinical material

Purpose The purpose of the study was to determine the different types of pseudotears of the posterior horn of the lateral meniscus caused by the nearby meniscofemoral ligaments (MFLs), and to correlate the presence of these ligaments with patterns of meniscal tear. Design Retrospective clinical study with patients and prospective observatory study with cadaveric material. Patients Magnetic resonance imaging studies of the knee in 49 patients who had subsequent arthroscopy of the knee performed over a 1-year period at a single institution were reviewed by two readers in consensus for the presence and morphology of the MFLs of Humphry (LH) and Wrisberg (LW). Ten cadaveric knee specimens were used for MRI, anatomic, and histologic study. Results The LH was present in 55% of patients, the LW in 94%, and both were present in 44.9%. The thickness of the LH and LW ranged from 1–3 mm (mean 1.9, SD 0.61), and from 1–3.8 mm (mean 1.8, SD 0.65) respectively (p > 0.05). A pseudotear in the posterior horn of the lateral meniscus was present in 63% of patients. In 13% the pseudotear was vertically oriented, and in 87% the pseudotear had an anterosuperior to posteroinferior orientation, ranging from 37 to 87°. There was no association between the presence of one or both MFLs and the occurrence of medial or lateral meniscal tears (p > 0.05). Conclusion Meniscofemoral ligaments are frequent anatomical structures that are found in the majority of knees with MRI. They commonly cause a pseudotear of the posterior horn of the lateral meniscus that can be simple, double, or complex in appearance, with vertical or anterosuperior to posteroinferior orientation.     

Magnetic resonance imaging of knee injuries in children

The appearances of knee injuries on MR imaging are less well documented in children than adults. Some patterns of injury are shared by both groups of patients, e. g. meniscal damage. The frequency of specific injuries may differ, e. g. anterior cruciate ligament (ACL) tear. Congenital abnormality, coexistent pathology and previous treatment of the knee appear to be associated with meniscal problems. Discoid menisci are seen most frequently in children and have unique features on MR scans. Cruciate ligament tears are difficult to diagnose in the smallest children. The ACL may not be identified due to its small size. Normal bone marrow signal may be confused with marrow infiltration or bone microfracture. Radiographically occult fractures around the knee appear to be strongly associated with ligamentous injury as in adult patients. Osteochondral fractures, osteochondral lesions and articular cartilage damage are revealed on MR scans, but their long-term effects are uncertain. It is possible to diagnose a range of knee injuries on MR scans in children. The biggest diagnostic challenge is in pre-school children. Received 13 December 1996; Revision received 13 March 1997; Accepted 14 March 1997     

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。     

Comparison of T1rho relaxation times between ACL-reconstructed knees and contralateral uninjured knees

Purpose

The goal of this study is to compare the cartilage of anterior cruciate ligament (ACL)-reconstructed and uninjured contralateral knees using T _1ρ MRI 12–16 months after ACL reconstructions.

Methods

Eighteen patients with ACL-reconstructed knees (10 women, 8 men, mean age = 38.3 ± 7.8 years) were studied using 3T MRI. Injured and contralateral knee MR studies were acquired 12–16 months post-operatively. Cartilage sub-compartment T _1ρ values of each injured knee were compared with the contralateral knee’s values. Subgroup analysis of sub-compartment T _1ρ values in both knees was performed between patients with and without meniscal tears at the time of ACL reconstruction using a paired Student’s t test.

Results

In ACL-injured knees, the T _1ρ values of the medial tibia (MT) and medial femoral condyle (MFC) were significantly elevated at 12–16 months follow-up compared to contralateral knees. Patients with a medial meniscal tear had higher MFC and MT T _1ρ values compared to respective regions in contralateral knees. Patients with lateral meniscal tears had higher lateral femoral condyle and LT T _1ρ values compared to respective regions in contralateral knees. There were no differences between the injured and contralateral knees of patients without meniscal tears.

Conclusions

T _1ρ MRI can detect significant changes in the medial compartments’ cartilage matrix of ACL-reconstructed knees at 1 year post-operatively compared to contralateral knees. The presence of a meniscal tear at the time of ACL reconstruction is a risk factor for cartilage matrix degeneration in the femorotibial compartments on the same side as the meniscal tear.