The MRI appearance of cystic lesions around the knee

This review presents a comprehensive illustrated overview of the wide variety of cystic lesions around the knee. The aetiology, clinical presentation, MRI appearances and differential diagnosis are discussed. Bursae include those related to the patella as well as pes anserine, tibial collateral ligament, semimembranosus–tibial collateral ligament, iliotibial and fibular collateral ligament–biceps femoris. The anatomical extension, imaging features and clinical significance of meniscal cysts are illustrated. Review of ganglia includes intra-articular, extra-articular, intraosseous and periosteal ganglia, highlighting imaging findings and differential diagnoses. The relationship between proximal tibiofibular joint cysts and intraneural peroneal nerve ganglia is discussed. Intraosseous cystic lesions, including insertional and degenerative cysts, as well as lesions mimicking cysts of the knee are described and illustrated. Knowledge of the location, characteristic appearance and distinguishing features of cystic masses around the knee as well as potential imaging pitfalls such as normal anatomical recesses and atypical cyst contents on MR imaging aids in allowing a specific diagnosis to be made. This will prevent unnecessary additional investigations and determine whether intra-articular surgery or conservative management is appropriate.     

MRI诊断半月板囊肿的价值及临床意义

目的 分析半月板囊肿的MRI表现,评价MRI诊断半月板囊肿的价值及临床意义.资料与方法 回顾性分析经手术病理证实的34例半月板囊肿患者的MRI表现,探讨半月板囊肿部位、形态、信号特征及其与半月板的毗邻关系.结果 34例半月板囊肿(内、外侧半月板囊肿发生比率为1:2.4),包括:半月板旁型囊肿25例(73.5%),半月板内型囊肿4例(11.8%),滑膜囊肿5例(14.7%).半月板囊肿多呈类圆形的囊性肿块,边缘光滑锐利,信号均匀,SE-T_1WI呈等或稍低信号,TSE-T_2WI呈稍高信号,MEDIC呈高信号,其中半月板旁型囊肿的典型表现呈"吹气球征".结论 MRI能够对膝关节半月板囊肿进行准确定位、分型,并清晰显示其与半月板的毗邻关系.因此,MRI检查可作为评价半月板囊肿的首选方法,对半月板囊肿的治疗具有重要指导意义.     

Evaluation of ganglion cysts using vastly undersampled isotropic projection reconstruction (VIPR)

For some atypical para-articular ganglia, the presence of a joint connection is highly controversial. The proper preoperative diagnosis and identification of this joint connection for ganglion cysts is important for patient treatment and outcome. MRI is the imaging modality of choice when evaluating such lesions, but the detection of subtle joint connections remains difficult with conventional MR protocols. We investigated the utility of a steady-state free-precession acquisition with isotropic high resolution using the vastly undersampled isotropic projection reconstruction (VIPR) pulse sequence to determine if joint connections for ganglion cysts could be seen more effectively, using the knee region as a model. We evaluated four patients: two with peroneal intraneural ganglion cysts, one with adventitial cystic disease of the popliteal artery, and one patient with a more typical extraneural (intramuscular) cyst. Both conventional MR and VIPR techniques were used. In our clinical experience, we found VIPR to be superior to conventional MR techniques in detecting and depicting joint connections in typical and atypical ganglion cysts around the knee.     

Giant synovial cyst of knee treated arthroscopically through a cystic portal

Synovial cysts are well-defined fluid filled cysts that can extend for a variable distance outside the joint space. These cysts can sometimes grow to a large size making its treatment challenging especially when associated with intra-articular pathologies.We describe a case of giant synovial cyst arising from the left knee and extending to the medial proximal calf in a 77-year old female who presented with knee joint pain, episodes of locking and calf mass occurring within 2 months of onset. Imaging studies also showed associated medial and lateral meniscal tears with medial compartment and patellofemoral osteoarthritis. The cyst was treated by disrupting the valvular mechanism using a standard posteromedial portal and complete excision of the cyst wall via a posteromedial cystic portal. The meniscal lesions were dealt with through the standard anterior portals. At 25-month follow up there were no signs of recurrence of the cyst clinically or with MRI. The cystic portal technique is effective in treating a giant synovial cyst of the knee even in the presence of meniscal tears and high grade chondral lesions. An erratum to this article can be found at     

The quadriceps tendon cyst: an uncommon cause of chronic anterior knee pain

The causes of knee pain are manifold. One of the uncommon causes of chronic anterior knee pain are cysts and ganglia. Magnetic resonance imaging not only reveals the intra-articular pathology but also accurately depicts such cystic structures about the knee. As part of this case report, a cyst of the lateral border of the quadriceps tendon is presented as a cause of such discomfort. Although cystic lesions around the knee are a common clinical problem, the described location is rare. After surgical revision of the lateral border of the quadriceps tendon and excision of the cyst, the patient was found to be asymptomatic.     

Arthroscopic all-inside suture of symptomatic Baker’s cysts: a technical option for surgical treatment in adults

Synovial fluid caused by repeated effusions may replete the gastrocnemius-semimembranosus bursa (GSB) communicating with the knee joint. Fluid trapped inside the GSB through an alleged unidirectional valve-like mechanism forms a so-called Baker’s cyst. Since a significant association of Baker’s cysts with knee joint disorders has been reported, treatment should primarily address articular lesions causing recurrent effusions. Arthroscopic surgery provides an effective treatment in that both the cyst and associated joint disorders can be optimally visualized and accordingly treated. In the present paper an all-inside arthroscopic technique for suturing the gateway to the GSB through an anterolateral viewing portal and a posteromedial working portal is proposed. The rationale underlying this technique is that no conclusive evidences exist that the one-way valve-like mechanism is purely anatomical. A retrospective study was conducted on 22 patients (9 males and 13 females, mean age 56 ± 10 SD years) affected by a symptomatic Baker’s cyst associated to knee joint disorders. Pre- and post-operative evaluation at 2 year follow-up consisted of clinical assessment by Rauschning and Lindgren criteria and magnetic resonance imaging (MRI). The results showed that 96% of patients showed clinical improvement. Baker’s cyst disappeared in 64% of patients, reduced in 27% and persisted in 9% on MRI. All patients with cyst reduction exhibited clinical amelioration. Our results suggest the all-inside arthroscopic suture technique would improve Baker’s cyst-related symptoms by either disappearance or reduction of the cyst. We believe the availability of multiple arthroscopic techniques to treat symptomatic Baker’s cysts could broaden the therapeutic armamentarium of knee arthroscopists.     

Double-contrast arthrography in secondary popliteal cysts

The diagnosis of a popliteal cyst is usually made on the basis of a history of discomfort and pain in the medial portion of the popliteal region, together with the finding of a palpable mass in the popliteal fossa. The clinical diagnosis can be confirmed by knee arthrography, if the cyst communicates with the knee joint; in recent years, however, noninvasive US has also become an important diagnostic aid to the radiologist. The S. Anna Hospital (Ferrara) experience is here reported in the diagnosis of symptomatic popliteal cysts, with no valve mechanism at the connection with the joint cavity. Arthrography was performed on 438 patients with popliteal cysts to determine their extent and size in relation to the symptoms and to the presence of underlying knee pathology; only 76 patients from this group were then submitted to surgery. The authors confirm that popliteal cyst is a frequent occasional finding during knee arthrography which almost completely lacks any clinical relevance in most cases. Moreover, taking arthrographic findings as a starting point, the authors describe the different anatomotopographic patterns of popliteal cysts.     

MRI appearance of meniscal cysts

Purpose The purpose of this study was to review the MRI criteria for the distinction of meniscal cysts from other cystic lesions in the knee so that appropriate treatment may be planned.Design A retrospective review of 62 knee MRI scans possibly showing meniscal cysts was performed. The type of meniscal tear, the appearance of the connection between the cyst and the meniscal tear, and the location, size, morphology, and signal characteristics of the meniscal cysts were recorded. Other types of fluid collections that had been mistaken for meniscal cysts were described.Patients Sixty-two patients were studied, ages 16–79 years, 61% male, 39% female.Results and conclusions Most of the meniscal cysts (91%) occurred immediately adjacent to the meniscal tear (98% horizontal cleavage tears, 49% anterolateral), with the tear leading directly into the cyst. In two cases, the cyst had dissected into the soft tissues distant from the meniscus and a connecting stalk was visualized. Fluid collections in normal bursae and recesses that had been mistaken for meniscal cysts had no direct connection to a meniscal tear. MRI can be used to distinguish meniscal cysts from other fluid collections that may mimic meniscal cysts. Pitfalls can be avoided by familiarity with the normal bursal and capsular anatomy, and by the application of specific diagnostic criteria.     

MR imaging features of giant reservoir formation in the orbit: an unusual complication of Ahmed glaucoma valve implantation

We report the MR imaging findings of an unusually large fluid collection, so-called giant reservoir, around an Ahmed glaucoma valve implant that caused progressive proptosis in a patient with posttraumatic glaucoma. Although other cystic lesions of the juxtalacrimal area of the orbit, such as dermoid cyst, can present similar imaging findings, the characteristic morphology and location should lead the radiologist to the correct nature of this cystic lesion.     

Proximal tibiofibular joint synovial cyst—one pathology with three different presentations

Synovial cysts of the proximal tibiofibular joint are less common than synovial cysts of the knee joint but may present in a similar fashion and may be difficult to diagnose clinically. We report three cases of such synovial cysts: (1) the synovial cyst presented as an asymptomatic lump distal to lateral joint line of the knee; (2) the synovial cyst presented as a mass fluctuating in size with intermittent symptoms; (3) a man with a large mass in proximal anterior leg and drop foot. The patients were operated. The first and the third patients were treated successfully without recurrence, and complete recovery of the proneal nerve in third case ensued. The synovial cyst recurred in the second case; however, the patient refused a second operation. Age distribution and clinical manifestation of extraneural proximal tibiofibular joint synovial cyst is discussed in the light of relevant literature.     

关节旁骨内腱鞘囊肿的影像学诊断

目的 探讨关节旁骨内腱鞘囊肿的发病机制、临床表现及X线特征、诊断及鉴别诊断。资料与方法 回顾性分析经病理证实的11例关节旁骨内腱鞘囊肿的临床及影像学资料，其中5例位于膝关节附近，5例位于踝关节附近，1例位于肘关节，且均为单发。结果 11例X线表现：7例为单房性圆形或椭圆形密度减低区，其中2例与关节腔有一宽约1mm的通道；2例呈多房性囊状扩张，其内有粗细不等的间隔；另2例呈半圆形骨质缺损，开口朝向关节腔。11例均显示边界清楚，周围有宽约1mm的硬化边。结论 关节旁骨内腱鞘囊肿在临床和X线片上可早期诊断，但应与相关疾病鉴别，防止误诊。     

MR imaging of cysts, ganglia, and bursae about the knee

Cystic lesions around the knee comprise a diverse group of entities, ranging from benign cysts to complications of underlying diseases such as infection, arthritis, and malignancy. Their diverse causes result in varied prognoses and therapeutic options. Although the presentation of cystic masses may be similar, their management may differ, thus highlighting the importance of appropriate categorization. MR aids in the characterization of lesions by first localizing them, and then defining their relationship with adjacent structures and identifying any additional abnormalities. For the purpose of this article, the authors limit the scope of their discussion to benign cysts, ganglia, and bursae about the knee.     

MRI在半月板囊肿诊断中的应用

目的 探讨MRI在半月板囊肿临床诊断中的应用价值.方法 对18例经手术证实的膝关节半月板囊肿病例的MRI检查进行分析.结果 本组18例半月板囊肿发生于右膝11例,左膝7例.其中位于外侧半月板15例,内侧半月板3例.半月板囊肿的形态呈圆形、类圆形、三角形和不规则形,边界清楚,信号大致均匀,在T1加权像上为低或等信号,在T2加权像上为等或高信号,水激发序列图像上呈高信号.合并半月板损伤或退行性改变14例,其中Ⅲ°损伤9例.半月板囊肿起源于半月板前角15例,体部1例,后角2例.根据半月板囊肿与半月板的关系可以分为如下类型:半月板旁型14例,半月板内型1例,滑膜囊肿型2例.结论 半月板囊肿具有典型的影像学特征,MRI做为一种无创伤性影像学手段,可很好地显示半月板囊肿及其相关病变,为临床治疗提供全面的影像学信息.     

Popliteal cysts in adults. Prevalence, associated intraarticular lesions, and results after arthroscopic treatment.

The objective of this prospective study was to determine the prevalence of popliteal cysts and the associated intraarticular lesions in a group of 100 patients scheduled for arthroscopic surgery of the knee and to evaluate the results of arthroscopic treatment for these intraarticular lesions without removal of the cyst. One hundred patients without any knee complaints served as a control group. The diagnosis of a popliteal cyst was made on the basis of ultrasonography. The prevalence of popliteal cysts was 20% in the study group and 0% in the control group. Patients with a popliteal cyst had a significantly higher prevalence of medial meniscal tears (70% versus 19%) and of chondral lesions (85% versus 28%). Tears of the lateral meniscus, however, were more evenly distributed (20% versus 36%). Sixteen of 20 patients with a popliteal cyst were available for a follow-up examination 1 to 3 years after the arthroscopic procedure. Eleven popliteal cysts had persisted. Chondral lesions were the most relevant prognostic factor; all patients with persisting cysts had grade III or grade IV lesions. We conclude that the popliteal cyst is a secondary phenomenon and that treatment should address the underlying intraarticular lesions. In cases of osteoarthritis it may be impossible to treat the chondral lesion successfully in terms of eliminating the effusion.     

High-resolution ultrasonography (HRUS) of the meniscal cyst of the knee: Our experience

PURPOSE: This study was undertaken to assess the diagnostic accuracy of high-resolution ultrasonography (HRUS) in the detection of meniscal cysts. MATERIALS AND METHODS: Over a 2-year period, 1,857 patients underwent magnetic resonance imaging (MRI) of the knee for traumatic or degenerative disorders. All patients with MRI evidence of a meniscal cyst were studied by HRUS. HRUS was also performed on an equal number of patients without MRI evidence of meniscal cyst who were used as a control group. All HRUS examinations were conducted by a radiologist blinded to the MRI findings. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of HRUS were assessed with reference to MRI. All patients underwent surgery, and the resected masses were studied by histological examination. RESULTS: MRI allowed identification of a meniscal cyst in 52 patients. HRUS enabled correct detection of the meniscal cyst in 49/52 cases. In the control group, HRUS excluded the presence of meniscal cysts in all cases. HRUS had a sensitivity, specificity, PPV and NPV of 94.23%, 100%, 100% and 94.54%, respectively, for the detection of meniscal cysts. CONCLUSIONS: HRUS is a fairly reliable technique in the detection, characterisation and differentiation of the different forms of meniscal cyst.     

Extra-articular soft tissue ganglion cyst around the knee: focus on the associated findings

The aim of this study was to evaluate MR imaging findings of the associated findings in surrounding tissues of the extra-articular soft tissue ganglion cysts around the knee. We retrospectively reviewed MR images of 30 patients who had surgically confirmed extra-articular soft tissue ganglion cysts around the knee with focus on the associated findings in surrounding tissues, such as muscle, subcutaneous fat, bone, and nerve. The most common associated finding was the visualization of channel between ganglion cyst and the joint, which was demonstrated in 20 cases (continuous type in 12 cases and discontinuous type in 8 cases). Other associated findings were seen in 15 cases; pericystic edema (n=9), bony remodelling (n=3), and nerve involvement (n=3). The bony remodelling involved the proximal metaphysis of tibia in all 3 cases. Two patients with nerve involvement had deep peroneal nerve in subacute phase and one involved common peroneal nerve in chronic phase. The MR imaging is a useful imaging modality to evaluate the associated findings in extra-articular soft tissue ganglion cysts around the knee. The evaluation of these associated findings is helpful for the differentiation of ganglion cysts from other cystic lesions around the knee.     

纵隔囊性病变的CT与MRI诊断

目的：探讨纵隔囊性病变的CT、MRI诊断及鉴别诊断。方法：回顾性总结30例经手术、病理确诊的纵隔囊性病变的CT及MRI表现，包括胸腺囊肿7例，囊性畸胎瘤8例，气管、支气管囊肿9例，食管囊肿4例，囊性淋巴管瘤2例。结果：不同纵隔囊性病变均有其较特定的发病部位。7例胸腺囊肿中6例位于前上纵隔的胸腺区，1例位于前纵隔中下部；8例囊性畸胎瘤主要位于前纵隔中部、大血管起始处；9例气管、支气管囊肿位于中上纵隔，气管、支气管右旁区；4例食管囊肿，其中3例位于后纵隔，1例位于中纵隔；2例囊性淋巴管瘤，其中1例为颈纵隔型，1例为颈一腋纵隔型。结论：纵隔囊性病变虽无明显特征性影像学表现，仔细观察CT与MRI征象特点，结合发病部位，对提高本病的诊断具有重要意义。     

膝关节半月板囊肿22例MRI分析

目的：分析膝关节半月板囊肿的MRI特点，提高对该病的认识。方法：回顾性分析22例膝关节半月板囊肿的MRI表现并与关节镜或手术结果对照。探讨半月板囊肿发生的部位、形态、信号特征及与半月板的毗邻关系。结果：22例半月板囊肿中，内侧半月板囊肿4例(18．1％)，外侧半月板囊肿18例(81．8％)。22例半月板囊肿中显示半月板水平撕裂15例(68．2％)，纵行撕裂3例(18．1％)。结论：半月板囊肿好发于外侧半月板，并与半月板的撕裂相关，表明MRI对诊断半月板囊肿有较高的临床价值。     

颅内毛细胞型星形细胞瘤的影像学表现与临床病理对照研究

目的 探讨颅内毛细胞型星形细胞瘤(PA)的影像学特征及与临床病理的关系.资料与方法 对本院经病理证实的70例PA的CT和MRI表现进行回顾性分析,并与临床病理对照研究.结果 70例PA分别位于小脑28例、中线结构23例、大脑半球19例.11例在CT上可见钙化,12.8%在CT/MRI上可见出血性改变;而病理上14例可见钙化,31.4%可见陈旧性出血.在影像上37.1%的PA呈囊实性伴有壁结节强化而无囊壁强化,22.9%有囊壁及壁结节强化,12.9%为实性伴坏死并不规则不均匀强化,27.1%为实性伴有微囊或无囊性结构并明显均匀强化.扩散加权成像(DWI)上PA的实性成分呈等或低信号,ADC值平均1.63×10~(-3)mm~2/s.在MR灌注上肿瘤实性部分呈高灌注,肿瘤的肌酸(Cr)和N.乙酰天门冬氨酸(NAA)降低,并可见乳酸峰.结论 PA的影像学表现具有一定特征,小脑和大脑半球的PA以囊实性为主、中线结构PA以实性为主,PA内钙化和出血并不少见.MRI灌注、DWI和磁共振波谱(MRS)在PA的诊断和鉴别中具有一定的价值.     

Dissection of gas into an intraspinal synovial cyst from contiguous vacuum facet

Intraspinal synovial cysts probably originate from herniation of synovium through a weakened facet joint capsule. The computed tomographic (CT) findings of such lesions were recently reported. An additional characteristic is gas within the cyst as demonstrated by CT. We postulate the source to be an adjacent diseased facet joint with a vacuum cleft with consequent dissection of gas into the cyst.