Sonographic detection of Baker's cysts: comparison with MR imaging

OBJECTIVE: The objective of this study was to assess the ability of sonography to reveal Baker's cysts using MR imaging as a gold standard. MATERIALS AND METHODS: The study group consisted of 36 consecutive knees in 36 patients evaluated with both MR imaging and sonography. Inclusion criteria included axial proton density-weighted or T2-weighted MR images, a sonography report that documented the evaluation of the popliteal region of the knee, and sonographic and MR images that were available for review. The MR images were retrospectively reviewed for the presence of Baker's cyst (fluid signal between the semimembranosus and medial gastrocnemius tendons). Sonography reports were compared with the MR imaging results. The sonographic images were also retrospectively reviewed to determine whether any characteristic findings on sonography were significantly associated with the presence of Baker's cyst on MR imaging. RESULTS: Retrospective review of MR images revealed 21 Baker's cysts, one myxoid liposarcoma, one meniscal cyst, and 13 examinations with normal findings. The sonography reports revealed that the 21 Baker's cysts were correctly diagnosed, whereas the meniscal cyst and myxoid liposarcoma were misdiagnosed as Baker's cysts. Retrospective review of sonographic images showed a 100% sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the diagnosis of Baker's cyst when hypoechoic or anechoic fluid was present between the semimembranosus and medial gastrocnemius tendons. No other sonographic characteristics were significant. CONCLUSION: Identification of fluid between the semimembranosus and medial gastrocnemius tendons in communication with a posterior knee cyst indicates Baker's cyst with 100% accuracy.     

Third head of the gastrocnemius: an MR imaging study based on 1,039 consecutive knee examinations

Objective  The objectives of this study were to determine the frequency of a third head of the gastrocnemius and to describe the course, morphology, and insertion of the third head as seen on the basis of routine magnetic resonance (MR) imaging of the knee. Materials and methods  This study was a prospective study of 1,039 consecutive knee MR examinations which were performed for symptoms of pain not associated with claudication. The examinations were performed between September 2004 and January 2005 and were evaluated for the presence of an anomalous third head of the gastrocnemius and to determine its origin and course. Examinations were performed on a variety of magnets ranging from 0.2 to 1.5 T. Results  Of the 1,039 knees, 20 (1.9%) demonstrated an anomalous third head of the gastrocnemius which was seen arising near the midline of the posterior distal femur, between the mid and medial aspect, and joining the medial aspect of the lateral head of the gastrocnemius. The size of the third head varied from a thin threadlike muscle to a rather bulky muscle. In all of these patients, the third head coursed lateral to the popliteal vessels, and none coursed between the vessels. One additional case of a third head of the gastrocnemius was seen which joined the medial head of the gastrocnemius. Conclusion  A third head of the gastrocnemius joining the lateral head is not an uncommon variant, seen in 1.9% of knee MR examinations. Most are not associated with vascular symptoms. No grants or funds have supported this study.     

MR imaging of meniscal cysts: incidence, location, and clinical significance.

OBJECTIVE: The purpose of this study was to determine the incidence of medial versus lateral meniscal cysts as seen on MR imaging. MATERIALS AND METHODS: A total of 2572 knee MR imaging reports were retrospectively reviewed for the presence of meniscal tears and cysts. Two musculoskeletal radiologists reviewed all images with reported cysts. The type and location of meniscal tear and the presence and location of meniscal cysts were recorded. RESULTS: A total of 1402 meniscal tears were reported in 2572 MR examinations (922 [66%] of 1402 in the medial compartment; 480 [34%] of 1402 in the lateral compartment). Meniscal cysts were present in 109 (4%) of 2572 knees. Of the 109 cysts, 72 (66%) were in the medial compartment, and 37 (34%) were in the lateral compartment. Meniscal cysts were found in association with 72 (7.8%) of the 922 medial meniscal tears and 37 (7.7%) of the 480 lateral meniscal tears. Meniscal cysts showed direct contact with an adjacent meniscal tear in 107 (98%) of 109 cases, with the tear showing a horizontal component in 96 (90%) of 107 cases. CONCLUSION: Meniscal cysts occur almost twice as often in the medial compartment as in the lateral compartment. Medial and lateral tears occur with the same frequency. These findings, when viewed in the context of the historical literature on meniscal cysts, suggest that MR imaging detects a greater number of medial meniscal cysts than physical examination or arthroscopy, and that MR imaging can have an important impact on surgical treatment of patients.     

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.     

Pericruciate meniscal cysts arising from tears of the posterior horn of the medial meniscus: MR imaging features that simulate posterior cruciate ganglion cysts.

OBJECTIVE: The purpose of this study is to describe MR imaging features of an unusual type of meniscal cyst arising from tears of the posterior horn of the medial meniscus in 10 patients. MATERIALS AND METHODS: Retrospective review of MR examinations of the knee was performed of 10 patients (nine men, one woman; mean age, 39 years) in whom evidence of a meniscal tear and a cyst-like structure around the posterior cruciate ligament (PCL) was seen. RESULTS: An oval mass with low signal intensity on T1-weighted MR images and increased signal intensity on T2-weighted MR images posterior to the PCL, simulating a PCL ganglion cyst, was seen in all 10 patients. A tear of the posterior horn of the medial meniscus was also seen in all patients. The sites of communication between the cyst and meniscal tear were observed in sagittal MR images in eight patients. Septation within the cyst and associated joint effusion were seen in eight and four patients, respectively. Arthroscopy in eight patients and transmeniscal needle drainage in the other two patients confirmed both the meniscal tear and the pericruciate meniscal cyst. CONCLUSION: Pericruciate meniscal cysts cause fluid collections posterior to the PCL, simulating a PCL ganglion cyst. Careful analysis of the posterior horn of the medial meniscus should be performed when a cyst-like structure is seen adjacent to the PCL.     

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.     

Prevalence and size of meniscal cysts,ganglionic cysts,synovial cysts of the popliteal space,fluid-filled bursae,and other fluid collections in asymptomatic knees on MR imaging

OBJECTIVE: The purposes of this study were to evaluate the prevalence and determine the size of meniscal cysts, ganglionic cysts, synovial cysts of the popliteal space, fluid-filled bursae, and other fluid collections on MR images of asymptomatic knees. MATERIALS AND METHODS: MR images of 102 asymptomatic knees were evaluated with regard to the prevalence of meniscal cysts, ganglionic cysts, synovial cysts of the popliteal space, fluid-filled bursae, and other fluid collections. The MR examinations were performed in patients (mean age, 42.8 years; age range, 18-73 years) with clinically suspected meniscal lesions in the contralateral knee. The craniocaudal, anteroposterior, and mediolateral diameters of detectable abnormal fluid collections were measured. RESULTS: Medial meniscal cysts (mean size [craniocaudal x anteroposterior x mediolateral], 9 x 6 x 13 mm) were found in four asymptomatic knees. Neither lateral meniscal cysts nor ganglionic cysts of the cruciate ligaments were identified. Twenty-six synovial cysts of the popliteal space (Baker's cyst)-consisting of 11 gastrocnemius portions (mean size, 19 x 8 x 10 mm) and 15 semimembranosus portions (mean size, 20 x 7 x 9 mm)-were found in 19 knees. Twenty-four (92%) of these cysts had a maximal diameter of 30 mm or less. Fluid-filled bursae were found in 49 knees. The deep infrapatellar bursa was most commonly involved (42 knees; mean size, 6 x 3 x 5 mm). Fluid-filled anserine bursae (mean size, 27 x 12 x 10 mm) were detected in five knees. CONCLUSION: Meniscal cysts may be present in asymptomatic knees, at least on the medial side. Synovial cysts of the popliteal space can be found in approximately one fifth of asymptomatic knees. Their maximal diameter is usually smaller than 30 mm.     

Magnetic resonance imaging signs of iliotibial band friction in patients with isolated medial compartment osteoarthritis of the knee

Background  The purpose of this retrospective study was to assess the frequency of magnetic resonance imaging (MRI) signs of iliotibial band friction (ITBF) in patients with advanced medial compartment knee osteoarthritis. Material and methods  Proton density-weighted (PDw) fat-saturated (fatsat) MR images (1.5 T, slice thickness (SL) 2.5–3 mm, eight-channel phased array coil) of 128 patients with isolated advanced osteoarthritis of the medial knee compartment and complete or subtotal (>80%) loss of cartilage were evaluated. There were 41 men and 87 women. Mean age was 63 years, range 34–89 years. The control group consisted of 94 patients with medial meniscus degeneration without cartilage loss (56 men and 38 women, mean age 50 years, range 16–89 years). MRI signs of ITBF were evaluated in both groups [poorly defined abnormalities of signal intensity and localized fluid collection lateral, distal or proximal to the lateral epicondyle; signal intensity abnormalities superficial to or deep by the iliotibial band (ITB)]. Transverse images were evaluated separately. Consensus evaluation using all imaging planes was performed. Results  Of 128 patients with osteoarthritis, 95 had moderate or advanced MRI signs of ITBF (74.2%). Eighty-nine patients (69.5%) had advanced degeneration of the meniscus. In the control group, 26 of 94 patients had only moderate MRI signs of ITBF. There was a statistically significant difference between both groups for the presence of MR signs of ITBF (P ≤ 0.01). Conclusion  MRI signs of ITBF were frequently present in patients with severe medial compartment osteoarthritis of the knee. Joint space narrowing with varus knee deformity may be a cause of ITBF. Level of evidence  Level 4 (Historic, non-randomized, retrospective, cohort study with a control group)     

Intra-articular ganglion cysts of the knee: clinical and MR imaging features

The purpose of this study was to present clinical and MR imaging features of intra-articular ganglion cysts of the knee. Retrospective review of 1685 consecutive medical records and MR examinations of the knee performed at three imaging centers allowed identification of 20 patients (13 men and 7 women; mean age 35 years), in whom evidence of intra-articular ganglion cyst was seen. Of the 20 ganglion cysts, 5 were found in the infrapatellar fat pad, 10 arose from the posterior cruciate ligament, and 5 from the anterior cruciate ligament. Three of five patients with ganglion cyst in the infrapatellar fat pad had a palpable mass. In 7 of 15 patients with ganglion cyst in the intercondylar notch, exacerbation of pain occurred in a squatting position. On four MR arthrographies, ganglion cysts were an intra-articular round, lobulated, low signal intensity lesion. Five cases of fat-suppressed contrast-enhanced T1-weighted SE images demonstrated peripheral thin rim enhancement. The clinical presentation of intra-articular ganglion cyst is varied according to its intra-articular location. The MR appearance of intra-articular ganglion cyst is characteristic and usually associated with the cruciate ligament or the infrapatellar fat pad. Magnetic resonance arthrography has no definite advantage over conventional MR in the evaluation of the lesion. For intra-articular ganglion cyst in the infrapatellar fat pad, fat-suppressed contrast-enhanced MR imaging could be useful, because a thin, rim-enhancing feature of intra-articular ganglion cyst allows it to be distinguished from synovial hemangioma and synovial sarcoma. Received: 29 June 2000 Revised: 13 September 2000 Accepted: 15 September 2000     

The deep infrapatellar bursa: prevalence and morphology on routine magnetic resonance imaging of the knee

OBJECTIVE: To evaluate the presence, location, and dimensions of the deep infrapatellar bursa on routine magnetic resonance (MR) imaging of the knee. METHODS: The study group consisted of 213 knees in 204 consecutive individuals who had undergone routine MR imaging examination of the knee within a 365-day period. Magnetic resonance examinations consisted of T1-, proton-density-, and T2-weighted sagittal; spectral presaturation inversion recovery coronal; and T2*-weighted transverse sequences. Exclusion criteria were previous knee arthroscopy or surgery or the presence of a mass lesion infiltrating the infrapatellar fat pad. The presence, location, and dimensions of the deep infrapatellar bursa were studied. The bursa was also analyzed with regard to knee joint synovial effusion (absent, mild, or marked). RESULTS: The deep infrapatellar bursa was detected in 68% of the knees, most commonly on the lateral paramedian sagittal MR images. There was no statistically significant difference between male and female subjects or between the knee sides with regard to the detection of the deep infrapatellar bursa (P > 0.05). No correlation was found between synovial effusion and the presence of the deep infrapatellar bursa. The mean anteroposterior and craniocaudal dimensions of the deep infrapatellar bursa on sagittal T2-weighted MR images were 2.1-2.7 mm and 7.3-9.1 mm, respectively, on its lateral, central, or medial location within the sagittal MR image stack. CONCLUSION: An awareness of the dimensions and location of the deep infrapatellar bursa is important in distinguishing it from pathologic lesions (eg, bursitis).     

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.     

The MR appearance of cruciate ganglion cysts: a report of 16 cases

Intra-articular ganglion cysts arising from the cruciate ligaments are unusual lesions, there being only nine previously reported cases. We report 16 cases and describe their MR appearance. Nine ganglia originated from the posterior cruciate ligament, most often appearing as well-defined multilocular lesions. The seven ganglia arising from the anterior cruciate ligament most often appeared as fusiform cystic lesions extending along and interspersed within the fibers of the ligament. Although uncommon, intra-articular ganglion cysts arising from the knee appear to have a distinctive MR appearance which should allow their correct diagnosis.     

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.     

MR imaging of the tarsal tunnel and related spaces: normal and abnormal findings with anatomic correlation

The tarsal tunnel syndrome may be caused by extrinsic or intrinsic pressure on the posterior tibial nerve or its terminal branches. The specific symptoms depend on the extent of nerve involvement, and compression distal or proximal to the tarsal tunnel may result in variants of the syndrome. To define better the capability of MR imaging for evaluating this entity, we performed MR imaging on three normal subjects and correlated the images with cryomicrotome sections. Six patients with symptoms suggestive of tarsal tunnel syndrome also were studied with MR. In all normal subjects, MR images showed the flexor retinaculum and the structures passing deep to the retinaculum: the tibialis posterior tendon, flexor digitorum longus tendon, flexor hallucis longus tendon, and the posterior tibial neurovascular bundle. The medial calcaneal sensory branch(es) and the medial and lateral plantar nerves also were delineated. Mechanical causes of compression were shown in all six symptomatic patients. The pathologic entities included two neurilemomas, tenosynovitis involving all three tendons, a ganglion cyst arising from the flexor hallucis longus tendon sheath, posttraumatic fibrosis, and post-traumatic fibrosis with associated posttraumatic neuroma. The MR findings were confirmed surgically in five cases. MR imaging can accurately depict the contents of the tarsal tunnel and the courses of the terminal branches of the posterior tibial nerve. In our small series, MR imaging accurately showed the lesions responsible for tarsal tunnel syndrome.     

Effect of chondrocalcinosis on the MR imaging of knee menisci

OBJECTIVE: Our goal was to determine the influence of chondrocalcinosis on MR imaging in the detection of meniscal tears. MATERIALS AND METHODS: A retrospective review was performed of knee MR imaging and arthroscopy records from two university hospitals between 1996 and 1998. Seventy individuals had radiographic evidence of chondrocalcinosis and underwent knee MR imaging. Thirty-seven of these individuals had undergone arthroscopy for further evaluation of their symptoms. MR imaging sensitivity and specificity in the detection of medial and lateral meniscal tears were calculated in these 37 patients who had radiographic evidence of chondrocalcinosis and in a control group of 34 patients who underwent MR imaging and arthroscopy but did not have knee chondrocalcinosis. RESULTS: In the chondrocalcinosis group, MR imaging sensitivity, specificity, and accuracy for meniscal tear were 78%, 71%, and 78%, respectively, for the lateral meniscus, and 89%, 72%, and 81% for the medial meniscus. The control group showed sensitivity, specificity, and accuracy of 93%, 100%, and 97%, respectively, for the lateral meniscus and 100% in all cases for the medial meniscus. The MR imaging detection of meniscal tears in both the lateral and medial compartments combined is significantly poorer in the presence of chondrocalcinosis (p < 0.005). CONCLUSION: MR imaging sensitivity and specificity for detection of meniscal tear is decreased in the presence of meniscal chondrocalcinosis. Chondrocalcinosis appeared as a high-signal-intensity region on T1-weighted, intermediate-weighted, and inversion recovery sequences. The high signal of chondrocalcinosis on inversion recovery sequence is an interesting observation that to our knowledge has not been previously reported. Radiographic correlation with the MR imaging examination can help prevent overdiagnosing meniscal tears.     

MR imaging of meniscal cysts: evaluation of location and extension using a three-layer approach

PURPOSE: To analyze the extension of medial and lateral meniscal cysts relative to the capuloligamentous planes of the knee. MATERIALS AND METHODS: The MR images of 32 patients with meniscal cysts were reviewed. The location and extension of the meniscal cysts with reference to the capsule and ligaments were recorded. RESULTS: Most medial meniscal cysts were located posteromedially. Posteromedial meniscal cysts usually penetrated the capsule and were located between layer I and the fused layers II+III. From this site some extended anteriorly and then became located superficial to the superficial MCL. The location of lateral meniscal cysts was more varied. Anteriorly the cysts were located deep to the iliotibial band, whereas posterolateral cysts were located deep to the lateral collateral ligament. CONCLUSION: Although the site of capsular penetration of meniscal cysts is determined by the location of meniscal tears, the possible pathways of extension appear to be determined by the capsuloligamentous planes of the knee.     

MRI findings in patients with tibial nerve compression near the knee

The soleus sling has been recently identified as a site of compression of the tibial nerve resulting in tibial neuropathy. Diagnosis of soleal sling syndrome is difficult, and has been based mainly on clinical examination. Advances in MR imaging with high-resolution 3-Tesla scanners have made direct visualization of nerve pathology possible. With the use of high-resolution imaging and fat-suppression protocols, tibial nerve compression at the soleal fascial arch can be demonstrated in a subset of patients presenting with idiopathic tibial neuropathy. The purpose of this paper is to confirm the ability of MR imaging to demonstrate pathologic changes in the tibial nerve in patients presenting with soleal sling syndrome. Additionally, patients presenting with tibial neuropathy and ganglion cysts, both extra- and intraneural, were examined to determine if the site of compression corresponded to the region of the soleus sling. Nine patients were included in the study, two with idiopathic soleus sling syndrome, four with extraneural, and three with intraneural ganglion cysts. In the patients presenting with idiopathic soleus sling syndrome, MR imaging demonstrated a thickened soleus sling with T2 hyperintensity of the tibial nerve at the level of the sling and denervation changes in muscles of the posterior compartment of the leg. In patients with extraneural ganglion cysts, MR imaging demonstrated a “sandwich”-like compression of the tibial nerve between the cyst and the soleus sling with corresponding tibial nerve T2 hyperintensity and denervation change in posterior compartment muscles. No compression of the tibial nerve at the soleus sling was found in the intraneural ganglion population. We conclude that MR imaging is effective in demonstrating pathologic changes in the tibial nerve at the soleus sling. Based on the MRI findings, we also believe that the soleus sling is a component of the compression when patients present with extraneural ganglion cysts and tibial neuropathy near the knee; in these patients, we recommend release of the soleus sling as part of the definitive management.     

Magnetic resonance image segmentation using semi-automated software for quantification of knee articular cartilage—initial evaluation of a technique for paired scans

Purpose  Software-based image analysis is important for studies of cartilage changes in knee osteoarthritis (OA). This study describes an evaluation of a semi-automated cartilage segmentation software tool capable of quantifying paired images for potential use in longitudinal studies of knee OA. We describe the methodology behind the analysis and demonstrate its use by determination of test–retest analysis precision of duplicate knee magnetic resonance imaging (MRI) data sets. Methods  Test–retest knee MR images of 12 subjects with a range of knee health were evaluated from the Osteoarthritis Initiative (OAI) pilot MR study. Each subject was removed from the magnet between the two scans. The 3D DESS (sagittal, 0.456 mm × 0.365 mm, 0.7 mm slice thickness, TR 16.5 ms, TE 4.7 ms) images were obtained on a 3-T Siemens Trio MR system with a USA Instruments quadrature transmit–receive extremity coil. Segmentation of one 3D-image series was first performed and then the corresponding retest series was segmented by viewing both image series concurrently in two adjacent windows. After manual registration of the series, the first segmentation cartilage outline served as an initial estimate for the second segmentation. We evaluated morphometric measures of the bone and cartilage surface area (tAB and AC), cartilage volume (VC), and mean thickness (ThC.me) for medial/lateral tibia (MT/LT), total femur (F) and patella (P). Test–retest reproducibility was assessed using the root-mean square coefficient of variation (RMS CV%). Results  For the paired analyses, RMS CV % ranged from 0.9% to 1.2% for VC, from 0.3% to 0.7% for AC, from 0.6% to 2.7% for tAB and 0.8% to 1.5% for ThC.me. Conclusion  Paired image analysis improved the measurement precision of cartilage segmentation. Our results are in agreement with other publications supporting the use of paired analysis for longitudinal studies of knee OA.     

Characteristics of displaceable and nondisplaceable meniscal tears at kinematic MR imaging of the knee

PURPOSE: To prospectively determine if kinematic magnetic resonance (MR) imaging of the knee may demonstrate displacement of menisci with tears and, if so, to characterize displaceable and nondisplaceable meniscal tears. MATERIALS AND METHODS: The study was approved by the hospital's review board, and informed consent was obtained. Forty-two patients (30 men, 12 women; mean age, 36.9 years) with 43 arthroscopically documented meniscal tears visible at 1.5-T MR imaging underwent kinematic MR imaging with an open-configuration 0.5-T MR imager with their knees in supine neutral, supine with 90 degrees flexion and external or internal rotation, and upright weight-bearing positions. Analysis of meniscal movement was performed in different knee positions in the coronal MR imaging plane. Meniscal displacement--that is, meniscal movement of 3 mm or more (in the medial direction for the medial meniscus, in the lateral direction for the lateral meniscus)--was compared with the patient's pain level as assessed with a visual analog scale by using analysis of variance. RESULTS: Between the different knee positions, meniscal displacement of 3 mm or more (displaceable meniscal tears) was noted in 18 (42%) of 43 menisci with tears. Simultaneous occurrence of grade II or III ipsilateral collateral ligament lesions was present in all 18 displaceable meniscal tears, whereas a normal-appearing collateral ligament or collateral ligament lesion (grade I) was present in 22 of 25 nondisplaceable tears (P < .05). Displaced menisci most commonly had complex, radial, or longitudinal tear configurations (16 of 18, 89%). Patients with displaceable meniscal tears had significantly more pain than did patients with nondisplaceable meniscal tears (P < .001), independent of the concomitant knee abnormalities. CONCLUSION: Displaceable meniscal tears usually have longitudinal, radial, or complex configurations; such tears are associated with substantial ipsilateral collateral ligament lesions and pain.     

Chronic medial knee pain without history of prior trauma: correlation of pain at rest and during exercise using bone scintigraphy and MR imaging

Objective  The objective of this study was to correlate chronic medial knee pain at rest and during exercise with bone scintigraphic uptake, bone marrow edema pattern (BMEP), cartilage lesions, meniscal tears, and collateral ligament pathologies on magnetic resonance MR imaging (MRI). Materials and methods  Fifty consecutive patients with chronic medial knee pain seen at our institute were included in our study. Pain level at rest and during exercise was assessed using a visual analog scale (VAS). On MR images, BMEP volume was measured, and the integrity of femoro-tibial cartilage, medial meniscus, and medial collateral ligament (MCL) were assessed. Semiquantitative scintigraphic tracer uptake was measured. Multivariate linear regression analysis was performed. Results  At the day of examination, 40 patients reported medial knee pain at rest, 49 when climbing stairs (at rest mean VAS 33 mm, range 0–80 mm; climbing stairs mean VAS, 60 mm, range 20–100 mm). Bone scintigraphy showed increased tracer uptake in 36 patients (uptake factor, average 3.7, range 2.4–18.0). MRI showed BMEP in 31 studies (mean volume, 4,070 mm³; range, 1,200–39,200 mm³). All patients with BMEP had abnormal bone scintigraphy. Ten percent of patients with pain at rest and 8% of patients with pain during exercise showed no BMEP but tracer uptake in scintigraphy. Tracer uptake and signal change around MCL predicted pain at rest significantly (tracer uptake p = 0.004; MCL signal changes p = 0.002). Only MCL signal changes predicted pain during exercise significantly (p = 0.001). Conclusion  In chronic medial knee pain, increased tracer uptake in bone scintigraphy is more sensitive for medial knee pain than BMEP on MRI. Pain levels at rest and during exercise correlate with signal changes in and around the MCL.