0.2-Tesla magnetic resonance imaging of internal lesions of the knee joint: a prospective arthroscopically controlled clinical study

The results of magnetic resonance imaging (MRI) were compared with those of arthroscopy in a prospective series of 244 patients. A dedicated system for MRI of limbs and peripheral joints – the 0,2-T Artoscan (Esaote, Italy) – was used for imaging knee joint lesions. T1-weighted spin-echo sagittal images, T2-weighted gradient-echo coronal images, and axial views for lesions of the femoropatellar joint were acquired. Paraxial sagittal and oblique coronal views were obtained for imaging of the cruciate ligaments. This protocol allowed excellent visualization of the cruciate ligaments and medial and lateral meniscus in almost all patients. Compared with arthroscopy performed within 48 h after imaging, the sensitivity, specificity, and accuracy were respectively 93%, 97%, and 95% for tears of the medial meniscus; 82%, 96%, and 93% for tears of the lateral meniscus; 100%, 100%, and 100% for tears of the posterior cruciate ligament; 98%, 98%, and 97% for tears of the anterior cruciate ligament; and 72%, 100%, and 92% for full-thickness articular cartilage lesions. The examination can be performed within 30–45 min at lower cost than diagnostic arthroscopy. MRI with a 0.2-T magnet is a safe and valuable adjunct to the clinical examination of the knee and an aid to efficient preoperative planning. Received: 13 October 1997 Accepted: 3 March 1998     

Imaging of the knee joint with emphasis on magnetic resonance imaging

The knee joint is frequently affected by trauma as well as degenerative and inflammatory disorders, involving the internal structures (i.e. ligaments, menisci, cartilage, synovial membrane) and the adjacent bones. Plain radiographs represent an indispensable basis for diagnosis. For further analysis magnetic resonance imaging (MRI) has become the method of choice, and has widely replaced computed tomography, arthrography and stress examinations. Extensive experience has been accumulated in MRI of the knee joint in recent years. In addition, advances in MRI technology have had a major impact on diagnostic accuracy. In this paper, diagnosis of various lesions of the knee joint, such as meniscal and ligamental injuries, aseptic necrosis, lesions of the hyaline cartilage, occult fractures and inflammatory lesions will be discussed. Offprint requests to: M. F. Reiser     

Magnetic resonance imaging findings of surgically proven medial meniscus root tear: tear configuration and associated knee abnormalities

OBJECTIVE: To evaluate magnetic resonance imaging (MRI) findings of medial meniscal root tear and the correlation of medial meniscal root tear with other associated knee abnormalities. METHODS: We retrospectively assessed preoperative magnetic resonance images of 39 patients with arthroscopically confirmed medial meniscal root tear. Magnetic resonance imaging findings were retrospectively reviewed by 2 experienced musculoskeletal radiologists for consensus. We evaluated the configuration of meniscal root tear and the other associated knee abnormalities on MRI for direct correlation with arthroscopic findings. RESULTS: At arthroscopy, there were 36 radial tears and 3 complex tears involving the medial meniscal posterior horn roots. All 36 radial tears could be correctly diagnosed by MRI, with findings showing ghost sign on sagittal images in 100% (36/36), vertical linear defect on coronal images in 100% (36/36), and radial linear defect on axial image in 94% (34/36). However, all 3 complex tears were misdiagnosed as radial tears on MRI. Medial meniscal root tears displayed a strong association with degenerative joint disease in 97% (38/39). Medial meniscal root tears were also found in association with cartilage defects of the medial femoral condyle and medial meniscal extrusions (> or =3 mm) in 89% (34/38) and 67% (26/39), respectively. CONCLUSIONS: Medial meniscal root tears were usually posterior horn root radial tear. A high association with degenerative joint disease, cartilage defects of the medial femoral condyle, and medial meniscal extrusions (>/=3 mm) were also noted.     

4 T MRI of chondrocalcinosis in combination with three-dimensional CT, radiography, and arthroscopy: a report of three cases

Objective To describe 4 T MRI techniques in imaging chondrocalcinosis within the knee and examine the results together with those demonstrated using three-dimensional (3D) computed tomography, conventional radiography, and arthroscopy.Design and patients From a larger clinical imaging study of early osteoarthritis, knee arthroscopy patients were imaged using high-field MRI and high-resolution 3D CT prior to their surgery. Retrospective review of the imaging data diagnosed three patients with chondrocalcinosis. Fat-suppressed 3D spoiled gradient (3D SPGR) and two-dimensional fat-suppressed fast spin echo (FSE) imaging was performed at 4 T. The MR images, multi-planar reformatted CT (MPR-CT) and maximum intensity projection CT (MIP-CT) images, and radiographs were examined by a musculoskeletal radiologist for the presence and location of chondrocalcinosis. The findings from arthroscopy were also included.Results MRI showed 16 sites of punctate hypointense regions from 18 articular surfaces and five of six menisci with similar signal characteristics. Both meniscal chondrocalcinosis and meniscal tears were clearly visible using the 3D SPGR sequence. Only three sites were demonstrated to have calcification using MPR-CT and MIP-CT revealed an additional three. In articular cartilage surfaces showing surface disruption, arthroscopy demonstrated 11 sites with crystal deposition. Arthroscopy also revealed five menisci with calcification present.Conclusion Our preliminary findings suggest that imaging chondrocalcinosis using spoiled gradient 4 T MRI is superior and complementary to the other imaging modalities in the detection of crystal deposition in both articular cartilage and menisci.     

Magnetic resonance imaging of the knee

Magnetic resonance imaging (MRI) is an accepted non-invasive modality for evaluation of soft tissue pathology without exposure to ionizing radiation. Current applications demonstrate excellent visualization of the anatomy and pathology of various organs. Preliminary studies in the knee reveal fine resolution of anatomy and pathology involving the meniscus. The purpose of this study is to determine a prospective correlation between MRI scans and actual meniscal pathology as documented at the time of arthroscopy. MRI scans were obtained in 155 patients, on 156 knees (one patient with bilateral scans), with 86 patients (87 knees) eventually undergoing diagnostic and operative videoarthroscopy performed by the same surgeon (DWJ). All images were obtained on the same high-resolution 1.5 Tesla GE Signa Magnetic Resonance Scanner with the same radiologist performing all readings (PEB). The knees were studied in the coronal and sagittal plane using a spin echo sequence and 5 mm slice thicknesses. The menisci were described as having Grade 1, 2, or 3 changes, with Grade 3 reserved for complete tears. Using arthroscopy as the diagnostic standard, the accuracy of MRI in diagnosing medial and lateral meniscal tears was 93.1% and 96.6%, respectively with a Grade 3 MRI reading. For tears of the ACL, the accuracy was 96.6% as confirmed at arthroscopy. Five tears of the PCL were also documented by MRI and correlated with clinical evaluation. Other abnormalities seen were articular cartilage and osteochondral defects, bone tumors, tibial plateau fractures, Baker's cysts, and meniscal cysts. The MRI scan is a highly accurate, noninvasive modality for documentation of meniscal pathology as well as cruciate ligament tears in the knee.     

低场强MRI对膝关节半月板损伤的诊断价值探讨

目的评价低场强MRI对半月板损伤的诊断价值。方法对我院90例临床高度怀疑半月板损伤的患者行低场强MRI扫描和关节镜检查,并对其结果进行比较。结果本组90例患者的98个膝关节共累及103个半月板,经MRI诊断为真性撕裂者55个半月板．经父节镜证实为53个半月板;经MRI检查阴性而关节镜下见撕裂者2个半月板,MRI和父节镜检查均为阴性者30个半月板,其中有3个为盘状半月板。低场强MRI对半月板损伤的敏感性为9375％,特异性94．37％,准确性94．17％。结论低场强MRI是诊断半月板损伤无创性的极有价值的诊断疗法．是膝关节镜术前的重要榆查。     

1.5-T surface-coil MRI of the knee

Five normal knees and 20 knees with suspected abnormalities involving the menisci or articular surfaces were examined with high-resolution surface-coil MRI. Surgical correlation was available in 15 cases. Signal-to-noise ratios were optimized using a field strength of 1.5 T and a round 7.6-cm surface coil. Spatial resolution was maximized by using fields of view reduced to as small as 8 cm. Separate examinations of the medial and lateral joint compartments were performed with the surface coil positioned vertically adjacent to the meniscus of interest. Ten meniscal tears were identified using sagittal and coronal images. T1-weighted images were adequate to detect most meniscal tears, and T2-weighted images were useful for providing an "arthrogram effect" in the presence of a joint effusion. Extrameniscal lesions that were examined included osteonecrosis of the femoral condyle, subchondral cysts, rheumatoid arthritis, degenerative arthritis, and anterior cruciate ligament tears. MRI was useful in determining the integrity of articular cartilage overlying defects in the subchondral bone and in detecting gross cartilage lesions in arthritis, but was less sensitive than arthroscopy in evaluating moderate changes in the hyaline cartilage.     

MRI在膝关节软骨病变中的应用及研究进展

膝关节是人体最大最复杂的关节,关节软骨在维持关节正常活动中起到重要作用。关节软骨病变是影响膝关节稳定性的重要因素。磁共振成像（magnetic resonance imaging,MRI）对诊断膝关节软骨病变具有良好的空间分辨率和组织对比度,是目前评价关节软骨病变最有效的无创技术,其在膝关节疾病诊断中的应用日益广泛并显示出独特的优势。     

Application of MR imaging for internal derangement of the knee (orthopedic surgeon' view)

Magnetic resonance imaging is a noninvasive imaging modality with clear contrast and superior spatial resolution. These characteristics are especially useful for detecting pathology of the soft tissue of the knee joint, such as the menisci, ligaments and articular cartilage, which are difficult to diagnose using plain X-ray examination. MRI has become one of the first choice diagnostic modalities for the internal derangement of the knee joint, and is generally replacing some invasive arthrographic or arthroscopic examination. Pathology of the articular cartilage cannot yet be depicted clearly by MRI. We expect further development of the spatial resolution of MRI to make possible the detection of chondral lesions more clearly and precisely in the near future.     

Magnetic resonance imaging ofarticular cartilage injuries of the knee

Magnetic resonance imaging (MRI) is a widely available, powerful imaging modality in the United States that has rapidly become a mainstay for evaluation of the musculoskeletal system, largely because of its unparalleled depiction of most osseous and soft-tissue pathology. The application of MRI to detect cartilage injuries has evolved to the point where it is possible to noninvasively diagnose cartilage lesions that previously required an invasive examination, eg, arthrography or arthroscopy. However, successful cartilage imaging requires knowledge of the unique technical considerations and limitations of MRI. In this chapter we review current state-of-the-art knee MRI for three groups of chondral disorders: acute osteochondral fractures, osteochondritis dissecans, and degenerative lesions. The role of MRI in osteochondral fractures includes the demonstration of purely chondral intra-articular fragments and the identification of associated injuries, especially previously unrecognized subchondral bruises. MRI may also play a role in surveillance for osteochondral sequelae after injury. For osteochondritis dissecans, MRI can provide evidence supporting the diagnosis of a loose fragment and may aid in the evaluation of cartilage overlying osteochondral defects. Current MRI techniques can show moderate and severe lesions of chondromalacia and chondrosis. Newer techniques show potential for diagnosing these degenerative conditions at earlier stages when the changes are mild. We review these issues and provide examples showing the MRI appearance of common articular injuries.     

Articular cartilage regeneration of the knee joint after proximal tibial valgus osteotomy: a prospective study of different intra- and extra-articular operative techniques

In this prospective study high tibial osteotomy for medial gonarthrosis was performed in 95 patients (105 knee joints). The patients underwent simultaneously diagnostic and operative arthroscopic surgery of the knee joint. A follow-up arthroscopic examination could be performed in 75 patients (85 knee joints) at the time of implant removal. In group 1 (20 knee joints), the osteotomy was performed after diagnostic arthroscopy without arthroscopic operation of the knee joint. The fixation of the osteotomy was accomplished by staples, postoperative plaster fixation and physiotherapy. In group 2 (20 knee joints), osteotomy was performed without additional operative arthroscopy after diagnostic arthroscopy, internal fixation by AOT-plate, no external fixation postoperatively and physiotherapy. In group 3 (22 knee joints), osteotomy was performed with additional operative arthroscopy (Pridie drilling), internal fixation by AOT-plate no external fixation postoperatively no external fixation, physiotherapy and continuous passive motion. In group 4 (23 knee joints), osteotomy was performed with additional operative arthroscopy (abrasio-arthroplasty), internal fixation by AOT-plate, no external fixation postoperatively, physiotherapy and continuous passive motion. All patients underwent arthroscopic examination of the knee with cartilage biopsies taken from three different regions of the femoral condyle during the same operative session as the osteotomy. At follow-up arthroscopy cartilage biopsies were taken from the same regions. There was no great difference in clinical outcome after 1 year between all groups. Arthroscopy as well as routine and electron microscopy showed better cartilage regeneration in groups 3 and 4. Groups 1 and 2 showed only regeneration isles, sometimes not well fixed to the underlying bone, while in groups 3 and 4 cartilage regeneration was thicker and more stable, sometimes covering all of the pre-existing erosions. Therefore, we recommend osteotomy of the tibia for osteoarthritis together with operative arthroscopy in the same operative session. Received: 8 October 1997 Accepted: 5 April 1998     

Moving knee joint: technique for kinematic MR imaging

A system for magnetic resonance imaging of the knee joint during movement was developed by using a gating system and cine acquisition. The technique was used in 10 subjects: five with no history of knee pain or injury and five with tears of the anterior cruciate ligament. The normal ligaments and menisci appeared as low-intensity structures against intermediate-intensity hyaline cartilage. The ligament tears appeared discontinuous and faint against the background of the to-and-fro moving joint fluid.     

The importance of arthroscopy in sports injuries in children and adolescents

Within a 3-year period (1985–1988), 60 children and adolescents with knee injuries sustained mainly while skiing or playing football (soccer) underwent clinical examination, X-radiography and arthroscopy. Nearly all the patients still had open epiphyseal plates in the knee region. Arthroscopy revealed more severe intra-articular trauma than had been suspected on the basis of clinical findings. The skiing injuries most commonly involved anterior cruciate ligament tears, whereas injuries of the patellar retinaculum and medial meniscus lesions predominated in soccer injuries. On comparison with arthroscopic diagnosis, clinical diagnosis was erroneous in about 45%. The sost common mistaken clinical diagnosis was medial meniscus tear. Of the 60 knee joints subjected to arthroscopy, 40 were severely enough injured to warrant surgery. Only one had normal intra-articular findings. The study demonstrates that children and adolescents can suffer knee trauma requiring surgery, despite open growth plates. Downhill skiing and soccer are particularly risky sports in this respect. Therefore, sports injuries involving haemarthrosis are clearly an indication for arthroscopy, even in childhood and adolescence. Arthroscopy enables early identification of the type and extent of intra-articular trauma and subsequent early initiation of appropriate therapy.     

膝类风湿关节炎的MRI与病理对照研究

目的通过对膝类风湿关节炎(RA)病人关节软骨、软骨下骨髓及半月板进行MR-病理对照分析,探讨膝RA的MRI特点及病变发生机制。方法收集我院2008年11月—2014年12月间确诊为膝RA并行全膝关节置换术的11例病人(共13只膝关节)资料。评价关节软骨、软骨下骨髓及半月板的MRI表现,并在显微镜下对观察膝RA病人膝关节各部位组织的病理学特点。当细胞成分不确定时,使用免疫组织化学方法确定细胞种类。对关节软骨损伤MRI分级和半月板损伤MRI分度以及不同部位关节软骨下骨髓水肿和关节软骨、半月板损伤的病理学表现分度进行分析,并采用Mann-Whitney U检验对位于裸区和远离裸区的软骨下骨髓水肿的病理学表现分度进行比较。结果本组膝RA病人中大部分病人的MRI关节软骨破坏程度为4级,半月板破坏程度为4度。MRI显示52处软骨下骨髓水肿的部位中有18处(34.6%)于骨髓水肿上方覆盖有关节软骨且远离裸区,而34处(65.4%)的骨髓水肿位于裸区且邻近滑膜。在软骨下骨髓水肿的病理学表现中,纤维化、骨小梁镶嵌样结构及淋巴细胞浸润为最常见的表现。位于裸区和远离裸区骨髓水肿的两组间各种病理学表现分度差异均无统计学意义(均P0.05)。在关节软骨破坏的病理学表现中,纤维环、关节软骨破坏变薄及关节软骨增生为最常见的镜下病理表现。在全部13只切除的膝关节共26个半月板标本中,仅发现5个(19.2%)残留半月板标本,在MRI上均表现为萎缩、变薄,信号不均,其最常见的病理学表现为纤维化和吞噬包裹钙化碎片。结论晚期膝RA病人半月板及关节软骨破坏严重,骨髓水肿可发生于关节裸区或远离裸区部位,提示膝RA可同时累及多个部位,导致病人关节功能严重减退甚至丧失。     

Magnetic resonance tomography--a possibility for non-invasive meniscus diagnosis. 2. Results of clinical application

58 knee joints of 57 patients were examined via magnetic resonance tomography. Measurements were effected at 1.5 tesla using SE sequences in multilayer and dual-echo technique. Arthroscopic reference findings were available from all patients, comparison between arthroscopy and MRT in 93 menisci resulted in the present patient group in a negative predictive value of 97.4% and in a positive predictive value of 88.6%. Degenerative changes of the rupture-free menisci could be diagnosed via MRT in 15 cases. Besides the frequently observed central degeneration there were also superficial degenerations and fibrovascular proliferations. MRT can be recommended for pre-arthroscopy screening in suspected meniscus lesions on the basis of the methods of measurement and evaluation presented in this paper.     

低场MRI在膝关节退行性骨关节病中的诊断价值

目的探讨低场MRI对膝关节退行性骨关节的诊断价值。方法对经手术、关节镜或临床证实的60例(65个)膝关节退行性骨关节病的低场MRI表现进行回顾性分析。结果低场MRI能较好地显示膝关节关节软骨、半月板、骨质及韧带等变性、损伤,较传统X线检查有明显优势。结论低场MRI对膝关节退行性骨关节病的诊断有重要价值。     

The impact of MR imaging in sports medicine

Sports medicine is one of the most rapidly growing subspecialties in orthopedics. Magnetic resonance (MR) imaging in sports medicine includes depiction of normal anatomy and pathologic conditions in almost every joint in the body, but the MR examinations most frequently requested are of the knee and shoulder. The reported high accuracy of MR imaging in the knee has resulted in MR imaging being preferred to diagnostic arthroscopy by most leading orthopedic surgeons. MR imaging is particularly helpful for sports medicine surgeons in evaluating menisci to determine if they are repairable, in posterolateral corner syndrome, and in evaluating the hyaline articular cartilage. In evaluating the shoulder, MR arthrography is becoming the preoperative imaging procedure of choice for many sports medicine surgeons. Shoulder MR imaging is particularly important in helping identify abnormalities that may mimic rotator cuff or labral abnormalities at clinical examination, thus preventing unnecessary surgery in some patients. These abnormalities include Parsonage-Turner syndrome and quadrilateral space syndrome, each of which has a distinctive MR imaging appearance. As the field of sports medicine expands, radiologists will continue to see increased requests for MR imaging, because sports medicine and high-quality imaging are inextricably linked.     

Spin-echo and 3D gradient-echo imaging of the knee joint: a clinical and histopathological comparison

Objective: A clinical and histopathological comparison of 2D spin-echo (SE) and 3D gradient-echo (3DGE) sequences was under-taken for the knee joint. The purpose of the study was to evaluate the clinical results and to explain the different appearances of meniscal abnormalities on both 2DSE and 3DGE images. Patients, materials and methods: The clinical study comprised 45 patients with arthroscopically correlated MR imaging results. For the histopathological correlation, seven cadaveric knee joints were examined with the same 2DSE and 3DGE (FISP) imaging protocol and sliced in sagittal sections according to the MR images. Different stainings were used. Results: For the detection of meniscal tears, accuracy (82.2%) and positive predictive value (70.7%) of the 3DGE sequence were limited due to a high number of false positive findings. Cartilaginous lesions were more easily visible on 3DGE than on 2DSE images (sensitivity: 63.1% vs. 52.6%, respectively). As in the clinical study, the meniscal signal abnormalities of the cadaveric knee joints were much more extensive on the 3DGE images than on the 2DSE images. The 3DGE findings correlated better with degenerative meniscal changes which were visible microscopically. Conclusion: The high sensitivity of the 3DGE sequence for degenerative meniscal changes explains the lack of specificity for the differentiation between meniscal degeneration and tears with this sequence. The MR grading system for meniscal lesions is of limited value for the evaluation of 3D FISP images.     

T1 mapping联合常规MRI扫描方案评估膝关节软骨损伤

目的评估在常规MRI扫描方案中加入T1 mapping成像能否提高对膝关节软骨损伤的诊断效能。方法选取86例患者的88个膝关节接受了膝关节MRI检查和关节镜检查。MRI检查采用常规方案并加入T1 mapping成像。术前2位影像科医师对所有MRI检查图像进行一致的诊断,评估是否存在软骨损伤并进行软骨损伤MRI分级,首先评估常规MRI扫描方案的图像,然后评估T1 mapping联合常规MRI扫描方案的图像。由1位骨科医师在关节镜下进行软骨损伤关节镜分级并作为金标准。计算两种MRI扫描方案评估软骨损伤的敏感度和特异度,统计分析两种扫描方案的诊断结果是否存在差异。结果关节镜检出的256个软骨损伤,常规MRI扫描方案的敏感度、特异度分别为59.0%和98.6%,T1 mapping联合常规MRI扫描方案的敏感度、特异度分别为85.9%和93.2%。T1 mapping联合常规MRI扫描方案显著提高了MRI扫描诊断早期关节软骨损伤的敏感度,关节镜1级软骨损伤的敏感度从18.6%提高至71.2%,关节镜2A级软骨损伤的敏感度从74.3%提高至94.3%。上述两种扫描方案的结果差异均有统计学意义(P<0.05)。结论常规MRI扫描方案中加入T1 mapping成像,可提高对膝关节软骨损伤的敏感度,为临床诊断早期膝关节软骨损伤提供影像学依据。     

膝关节半月板放射状撕裂的MRI表现

目的 探讨MRI对膝关节半月板放射状撕裂的检出能力.方法 回顾性分析1085例经关节镜证实的膝关节半月板损伤中的半月板放射状撕裂107例(9.9%)患者的MRI资料,同时按住院号顺序采用等足巨抽样方法 ,抽取100例经关节镜证实的非放射状撕裂的半月板损伤患者作为对照组.所有患者均经MR检查,观察裂隙征及裂隙行走征、半月板分离征、半月板消失征及小半月板征4种征象,与关节镜结果 比较.结果 (1)107例半月板放射状撕裂患者中,最常见的发生部位是外侧半月板体部(71例,66.4%)和前体交界部(25例,23.4%).(2)107例半月板放射状撕裂中,MRI诊断放射状撕裂102例.100例半月板非放射状撕裂的半月板损伤中,MRI诊断11例为放射状撕裂,MRI诊断半月板放射状撕裂的敏感度、特异度、阳性预测值、阴性预测值分别为95.3%(102/107)、89.0%(89/100)、90.3%(102/113)、94.7%(89/94).(3)裂隙征和半月板分离征出现频率最高,102例中分别出现59例(57.8%)和43例(42.2%),是诊断放射状撕裂最重要的MRI征象.结论 MRI诊断半月板放射状撕裂的准确率较高,是目前术前无创诊断的最佳方法 .