The crowned dens syndrome. Evaluation with CT imaging

PURPOSE: The purpose of this study was to verify the value of computed tomography (CT) in the diagnosis of the "crowned dens" syndrome, not only in crystal deposition diseases, but also in other rheumatic or nonrheumatic conditions. MATERIALS AND METHODS: Thirty-eight patients (15 men and 23 women; mean age 55 years; age range 35-79) with neck pain were examined and divided into two groups: (1) patients already identified as rheumatic and referred for further investigation of the atlantoaxial region; (2) patients with symptoms confined to the cervical spine, with inconclusive radiographic findings. Unenhanced CT of the cervical spine (Tomoscan SR 7000 Philips, Eindhoven, Netherlands) was performed in all patients. There were 11 cases of rheumatoid arthritis (ten women and one man), two calcium pyrophosphate dihydrate crystal deposition disease (both women), one of systemic sclerosis (a woman), one of osteoarthritis (a man), one of seronegative arthritis (a man), four of neoplasm (one woman and three men) with suspected cervical involvement, one (a man) of haematological disease (lymphoma), one (a woman) of menopausal osteoporosis, ten (five men and five women) of recent or previous trauma with suspected involvement of the skull base and first cervical vertebrae and six of unknown painful cervical dysfunction (three men and three women). RESULTS: CT demonstrated calcific deposits around the dens in 12 patients (three men and nine women), in the transverse and alar ligaments, and in the anterior atlantooccipital membrane. CT revealed horseshoe- or crown-like calcification surrounding the odontoid process. In our series, other rheumatic diseases, especially rheumatoid arthritis, showed similar irregular calcifications of the atlantoaxial joint. Discussion. In calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, the spine may be the only site of involvement, generally asymptomatic. Crystals located in the transverse ligament of the atlas give rise to the crowned dens syndrome, usually in patients affected by severe degenerative lesions of the atlantoaxial joint and peripheral chondrocalcinosis. Symptoms may be absent, or a neurological compressive syndrome may develop. Symptoms tend to worsen with age. The diagnosis is not always easy, as the symptoms are similar to those of other diseases, such as meningitis, cervicobrachial pain, occipitotemporal headache, calcific tendinitis of the longus colli muscle, spondylodiscitis and retropharyngeal abscess. CONCLUSION: CT is the gold standard in identifying crowned dens syndrome, as it is able to depict the shape and site of calcification and any bone erosions. Radiography of other joints (wrist, knee, pubic symphysis) may help to ascertain whether the disease is due to calcium pyrophosphate dihydrate or hydroxyapatite crystals, and is therefore recommended for routine patient management. Magnetic resonance imaging (MRI) is indicated for the study of neurological complications.     

Calcification in calcium pyrophosphate dihydrate (CPPD) crystalline deposits in the knee: anatomic,radiographic, MR imaging,and histologic study in cadavers

Objective To demonstrate and determine the frequency and location of calcification within cadaveric knees with or without calcification typical of calcium pyrophosphate dihydrate (CPPD), utilizing histologic, radiographic and MR imaging techniques.Design and patients Ten cadaveric knees of elderly individuals that demonstrated no radiographic evidence of prior surgery or trauma were studied with MR imaging and subsequently sectioned in planes corresponding to those obtained with MR imaging. The slices were imaged with high-resolution radiography. Two musculoskeletal radiologists correlated the anatomic, MR and radiographic findings. Three of the knees, which did not demonstrate calcifications, were utilized as controls. Histologic sections were obtained from four knees that contained calcifications and from the three controls, and analyzed with special histologic stains that demonstrate phosphorus and calcium.Results Radiographic imaging and histologic analysis demonstrated widespread CPPD crystal deposition in four of the 10 knee specimens (40%). MR imaging demonstrated some calcifications only within the articular cartilage of the femoral condyles in three of the four (75%) specimens that had CPPD deposits. In all four specimens radiographs and histologic analysis were more sensitive than MR imaging. Histologic analysis demonstrated no evidence of CPPD crystals in the control specimens.Conclusion MR imaging is insensitive to the presence of CPPD deposits in the knee, even when such deposits are widespread. Our study suggests that the sensitivity of MR imaging was significantly better in detecting CPPD deposits in the hyaline cartilage of the femoral condyles when compared with other internal structures, even when such structures contained a higher amount of calcification.     

Relationship between the degeneration of the cruciate ligaments and calcium pyrophosphate dihydrate crystal deposition: anatomic,radiologic study with histologic correlation

To investigate the association of calcium pyrophosphate dihydrate (CPPD) crystal deposition and cruciate ligament (CL) degeneration, 10 cadaveric knees were studied with 1.5-T magnetic resonance imaging and sectioned in three planes. The slices were evaluated with high-resolution Faxitron radiography. The images and specimens were evaluated by two radiologists. Histologic sections were obtained from eight that contained calcifications and from two without calcifications. Radiographs and histologic analysis demonstrated CPPD crystal deposition in 80% of specimens and 75% of CLs in these eight specimens. Degenerative changes were observed in 75% of them. Such analysis demonstrated no evidence of CPPD crystals or degeneration in the control specimens.     

Calcium pyrophosphate dihydrate deposition in the transverse ligament of the atlas: an unusual cause of cervical myelopathy

A 75-year-old male presented with progressive myelopathy due to massive retro-odontoid deposits of calcium pyrophosphate dehydrate (CPPD) crystals. Magnetic resonance imaging revealed a non-enhanced isointense extradural mass on a T1-weighted image and a heterogeneous intense mass on a T2-weighted image. Computed tomography (CT) showed linear calcification within the mass. The mass was resected via a posterolateral approach resulting in marked improvement of the symptoms. Histological examination revealed birefringent rhomboid crystals consistent with CPPD. The preoperative differential diagnosis of periodontoid CPPD deposition disease in the elderly population should be considered, particularly if CT studies demonstrate small areas of calcification within the retro-odontoid mass.     

Subchondral fractures in osteonecrosis of the femoral head: comparison of radiography,CT, and MR imaging

OBJECTIVE: Our objective was to compare the sensitivity of unenhanced radiography, CT, and MR imaging in revealing subchondral fractures. SUBJECTS AND METHODS: Forty-five subjects with stage I and stage II osteonecrosis of the femoral head were included in the study as part of a multicenter clinical trial to evaluate the effectiveness of recombinant human bone morphogenetic protein as an adjuvant treatment to core decompression. Patients were evaluated with radiography, CT, and MR imaging 6 and 12 months after surgery. RESULTS: At 6 months, 18 fractures were shown on CT scans, but only 12 were detected on radiographs and six, on MR images. At 12 months, 20 subchondral fractures were detected on CT scans, but only 17 were seen on radiographs and 11, on MR images. Compared with CT, MR imaging has a sensitivity and specificity of 38% and 100%, and unenhanced radiography has a sensitivity and specificity of 71% and 97%, respectively. On T2-weighted MR images, the subchondral fractures were visualized as crescentic high-signal-intensity lines, and in all patients, on the corresponding CT scans, the fracture clearly breached the femoral cortex. CONCLUSION: CT reveals more subchondral fractures in osteonecrosis of the femoral head than unenhanced radiography or MR imaging. The high-signal-intensity line seen on T2-weighted MR images appears to represent fluid accumulating in the subchondral fracture, which may indicate a breach in the overlying articular cartilage.     

Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography

We sought to determine the prevalence of sternoclavicular (SC) joint calcium pyrophosphate dihydrate (CPPD) crystal deposition and its association with age, osteoarthritis, and atlantoaxial CPPD crystal deposition. In 209 consecutive patients, computed tomographic examinations of the cervical spine were retrospectively reviewed. Overall prevalence of CPPD crystal deposition in the SC joint was 17.2% (36/209), which increased with age (P<.0001). There was also a significant association between SC CPPD and osteoarthritis (P=.024) as well as atlantoaxial joint CPPD crystal deposition (P=.006).     

Rheumatoid arthritis and pseudo-rheumatoid arthritis in calcium pyrophosphate dihydrate crystal deposition disease

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease can lead to many clinical syndromes. One syndrome simulates rheumatoid arthritis and is thus called "pseudo-rheumatoid arthritis." Since some patients have true rheumatoid arthritis with CPPD crystal deposition disease, the clinician may have difficulty differentiating those patients from others who have the pseudo-rheumatoid syndrome. Such a diagnostic problem can be solved radiographically. Eleven patients with CPPD crystal deposition disease were studied; five had true rheumatoid arthritis and six had pseudo-rheumatoid arthritis. Because osseous erosions were not apparent in the arthropathy of uncomplicated CPPD crystal deposition disease, the detection of skeletal erosive changes indicated a true rheumatoid arthritis process.     

Hip arthropathy in a patient with primary hemochromatosis: MR imaging findings with pathologic correlation

Arthropathy is a major clinical manifestation in primary hemochromatosis, typically affecting the metacarpophalangeal joints. Hip arthropathy is not uncommon, with radiologic features resembling osteoarthritis or calcium pyrophosphate dihydrate (CPPD) crystal deposition disease. We describe the MR imaging findings of the hip in a patient with severe hip arthropathy and primary hemochromatosis and correlate them with the histopathologic findings. MR imaging showed severe degenerative changes, with large subchondral cysts and subchondral sclerosis in the femoral head and acetabulum. There was conspicuous correlation between MR imaging and pathologic findings of the resected femoral head. However, MR imaging failed to reveal intra-articular iron.     

MR imaging of the cervical spine in rheumatoid arthritis

The cervical spine was examined with MR imaging and conventional radiography in 23 patients with severe rheumatoid arthritis. All patients had neck pain and 17 also had neurologic symptoms. MR provided detailed information about soft-tissue lesions, vertebral dislocation, and narrowing of the spinal canal. Pannus surrounding the odontoid process was revealed in 14 patients, all with horizontal atlantoaxial subluxation. Compression of the medulla and/or spinal cord, caused by dislocated vertebrae and/or the soft-tissue mass around the odontoid process, was seen in 15 patients. When there was more than one dislocation the most important level could be determined. Posterior occipitocervical fusion had been performed in six of the patients, and in only two of these was adequate analysis of the upper cervical spine impossible because of artifacts from metal (stainless steel wires and pins). Sagittal MR in the neutral position combined with conventional radiography, including lateral views in flexion and extension, provided all the information necessary for further clinical management of rheumatoid arthritis of the cervical spine.     

Imaging findings of sacroiliac joints in spondyloarthropathies and other rheumatic conditions

Purpose

The authors sought to evaluate the role of the different imaging techniques in the study of sacroiliac joints in patients with spondyloarthropathies (SpA) and other rheumatic conditions and to assess potential pitfalls in the radiological diagnosis.

Materials and methods

Forty-three consecutive patients with sacroiliitis as the predominant symptom of a rheumatic disorder were retrospectively studied. Radiography, computed tomography (CT) and magnetic resonance (MR) imaging were performed. The following imaging findings were evaluated: bone marrow oedema, intra-articular effusion, synovial reaction, joint-space widening, bone sclerosis or hyperostosis, subchondral erosions and, in final stages, joint-space narrowing and ankylosis. All images were independently reviewed by two musculoskeletal radiologists.

Results

Radiography demonstrated bone sclerosis in 10 patients (23%), subchondral erosions in 15 (34%), jointspace widening in 8 (18%), joint-space narrowing in 17 (39%) and ankylosis in 3 (6%). CT examination showed sclerosis of the sacroiliac joint in 17 patients (41%), subchondral erosions in 21 (53%), joint-space widening in 22 (53%), joint-space narrowing in 18 (43%) and ankylosis in 7 (17%). At MR, we found bone marrow oedema in 25 patients (92%), intra-articular effusion in 26 (96%), synovial reaction in 21 (77%) and joint-space widening in 5 (18%).

Conclusions

Radiological study of the sacroiliac joints in patients with different rheumatic disorders represents a problem of difficult diagnostic evaluation due to the complexity of the anatomical region and the variability of radiographic findings. The integrated use of conventional radiography, CT and MR imaging is suggested to avoid misdiagnosis.     

Imaging of sacroiliitis in early seronegative spondylarthropathy. Assessment of abnormalities by MR in comparison with radiography and CT

PURPOSE: To analyze the type and frequency of abnormalities of the sacroiliac joint (SIJ) in early seronegative spondylarthropathy (SpA) by MR in comparison with CT and radiography, assess the most appropriate MR sequences to be used, and introduce a new way of grading MR abnormalities of the SIJ. MATERIAL AND METHODS: The SIJs of 41 patients with early SpA (median duration of inflammatory low back pain of 19 months) were evaluated by MR imaging using STIR, T1, T2, and T1 fat saturated (FS) sequences before and after i.v. Gd contrast medium followed by staging of abnormalities. The findings were compared with those obtained by CT and radiography. RESULTS: MR and CT had equal efficacy superior to radiography in staging of erosions and osseous sclerosis. Only MR allowed visualization and grading of active inflammatory changes in the subchondral bone and surrounding ligaments in addition to bone marrow fatty accumulations. T2-weighted sequences did not contribute to assessment of sacroiliitis. CONCLUSION: MR of the SIJs is reliable in its visualization of joint erosions in early SpA and allows differentiation between active and chronic sacroiliitis. We recommend the following sequences: semicoronal T1 and both semicoronal and semiaxial STIR. If these images are normal, the examination can be finished; otherwise additional semicoronal T1 FS before and after i.v. contrast has to be performed as well as semiaxial post-contrast T1 FS.     

Tophaceous gout of the spine: MR imaging features

AIM: To define the magnetic resonance (MR) imaging features of tophaceous gout of the spine. MATERIALS AND METHODS: We present the MR imaging examinations of 4 patients with spinal tophaceous gout. Spin-echo T1-weighted and fast spin-echo T2-weighted images were obtained for all patients, and 2 patients had gadolinium-enhanced MR imaging studies. Corresponding computed tomography (CT) was performed in one patient. All images were evaluated for the characteristics of the gouty tophi. RESULTS: The gouty tophi were located at the lower thoracic (n=1) and lumbar (n=3) levels. All tophi yielded homogeneous intermediate to low signal on T1-weighted images and variable signal intensity on T2-weighted images, comprising small foci of very low signal intensity on all sequences. Gadolinium-enhanced MR imaging studies revealed homogeneous enhancement or heterogeneous peripheral enhancement. Diffuse stippled calcifications were found in the tophi on CT images. Periarticular tophi with juxtaarticular bony erosions around facet joints occurred in 3 patients. CONCLUSION: Spinal tophaceous gout should be considered in the differential diagnosis when periarticular deposits contain very low signal foci on all MR imaging sequences.     

Atlantoaxial subluxation. Radiography and magnetic resonance imaging correlated to myelopathy

Twenty-nine patients with atlantoaxial subluxation (18 with rheumatoid arthritis, 2 due to trauma, 4 with os odontoideum, and one each with polyarteritis nodosa, rheumatic fever. Klippel-Feil syndrome, achondroplasia, and cause unknown) were evaluated using a 0.22 tesla resistive MRI unit. Cord compression was classified into four grades according to the degree on magnetic resonance imaging. There were 7 patients with no thecal sac compression (grade 0). 10 with a minimal degree of subarachnoid space compression without cord compression (grade 1), 7 with mild cord compression (grade 2), and 5 with severe cord compression or cord atrophy (grade 3). Although the severity of myelopathy showed poor correlation with the atlantodental interval on conventional radiography, high correlation was observed between MR grading and the degree of myelopathy. The high signal intensity foci were observed in 7 of 12 patients with cord compression (grades 2 and 3) on T2 weighted images. Other frequently observed findings in rheumatoid arthritis included soft tissue masses of low to intermediate signal intensity in the paraodontoid space, erosions of the odontoid processes, and atlantoaxial impaction on T1 and T2 weighted images.     

Pre- and postoperative MR imaging of the craniocervical junction in rheumatoid arthritis

Ten patients with severe chronic rheumatoid arthritis with atlantoaxial subluxation were examined with conventional radiography and MR imaging of the cervical spine before and at an average of 6 months after posterior occipitocervical fusion. Periodontoid pannus formation was revealed by MR preoperatively in nine patients, all with mobile horizontal atlantoaxial subluxation. Compression of the medulla and/or upper cervical cord, due to subluxation and periodontoid pannus bulging into the spinal canal, was seen in seven patients. After the stabilizing surgery the periodontoid pannus had decreased in size in all patients with preoperative pannus. This reduction in the pannus seems to be the result of the atlantoaxial immobility achieved by the posterior fusion. Postoperatively, three patients had some remaining compression of the medulla and/or cord secondary to immobile subluxation, while the pannus posterior to the odontoid process had disappeared. Artifacts from the surgical stainless steel fixation material were confined to the posterior part of the neck on short TR/short TE MR images and did not interfere with the evaluation of the periodontoid region and the anterior part of the medulla/cervical cord. We found that flexion and extension lateral radiographs, combined with sagittal short TR/short TE MR images in the neutral position, enable preoperative evaluation of patients with rheumatoid arthritis in the cervical spine. Postoperative MR should be performed only if there are residual or new symptoms.     

寰枢椎失稳的MRI诊断价值

目的评价MRI在诊断寰枢椎失稳中的价值。资料与方法回顾性分析26例寰枢椎失稳的MRI表现和临床资料。结果骨性结构的改变包括骨性畸形11例,枢椎骨折12例,肿瘤所致寰枢椎椎体破坏3例。软组织改变包括横韧带断裂7例,咽后壁软组织挫伤出血3例,齿状突与前弓或两侧块间组织嵌入3例。颈髓的改变包括硬脊膜和颈段脊髓受压12例,脊髓信号改变10例。结论MRI对寰枢椎失稳的诊断具有重要价值。它能清晰显示骨性结构异常、韧带断裂情况及颈段脊髓损伤,因而对指导临床治疗有重意义。     

早期强直性脊柱炎骶髂关节病变的X线、CT和MRI对比研究

目的 比较X线平片、CT和MRI在早期强直性脊柱炎(AS)骶髂关节病变中的诊断价值.方法 对53例临床拟诊为AS的患者行骶髂关节X线平片和MR检查,MR平扫均包括骶髂关节斜冠状面T1WI、T2WI、短时反转恢复序列(STIR)、附加水激励的三维稳态快速梯度回波序列(3D-BTFE-WATS),其中24例同时行脂肪抑制T1WI增强检查;25例患者同时行CT检查.分析患者的影像资料,应用x2检验对X线平片、CT和MRI显示骨侵蚀破坏敏感度进行统计学分析.结果 53例患者的106侧骶髂关节中,X线平片和MRI显示关节面下骨侵蚀病变分别为16侧和63侧;25例CT检查中显示26侧骶髂关节面下存在骨侵蚀破坏.CT和MRI显示骨侵蚀敏感度相近(x2=0.16,P＞o.05),两者均优于x线平片(x2值分别为14.44和17.36,P值均＜0.05),在所应用的MR序列中,3 D-BTFE-WATS显示骨侵蚀破坏最佳.MRI除显示AS骶髂关节慢性骨结构改变外,显示骨髓水肿 32例、滑膜增厚和(或)异常强化35例,脂肪沉积16例、韧带附着点炎15例、被膜炎9例和关节软骨破坏31例.结论 MRI能发现X线平片和CT不能显示的骨髓水肿和滑膜炎等急性炎性改变,早期诊断价值优于X线平片和CT.     

Diagnostic performance of MR imaging in the assessment of subchondral fractures in avascular necrosis of the femoral head

Objective  A prospective study was conducted to determine the accuracy of routine magnetic resonance (MR) imaging in correctly identifying subchondral fracture in avascular necrosis of the femoral head without apparent focal collapse on standard radiographs. Materials and methods  Spiral computed tomography (CT) with coronal and sagittal reformations and routine MR imaging with spin-echo T1WI and fat-suppressed spin-echo T2WI coronal, axial, and sagittal images were performed in 28 hips of 25 patients (M/F = 20:5; age 16–76 years) suffering from early-stage avascular necrosis of the femoral head on standard radiographs. The MR images were reviewed by a musculoskeletal radiologist and a general radiologist in blinded fashion. Using CT as the standard of reference, the accuracy of MR imaging in diagnosing subchondral fractures in avascular necrosis was evaluated. Results  When the diagnoses of the two readers were compared with each other, only 16 of the 28 diagnoses (57.5%) agreed. Seventeen of the 28 MR imaging readings (60.7%) made by the musculoskeletal radiologist and 15 of the 28 (53.5%) made by the general radiologist agreed with those of the CT standard. False-positive diagnosis (that is, diagnosis of fracture when no fracture could be seen on CT) was more common than false-negative diagnosis. Conclusions  The accuracy of routine MR imaging in the evaluation of subchondral fracture is not satisfactory. False-positive diagnosis is not uncommon. Interpretation of routine MR imaging readout should be guarded.     

Cervical rheumatoid arthritis: value of flexion and extension views in imaging

The magnetic resonance (MR) imaging findings in the cervical spines of eight patients with long-standing polyarticular rheumatoid arthritis were reviewed. Three pathologic conditions were readily demonstrated: anterior atlantoaxial subluxation (n = 6), atlantoaxial impaction (n = 6), and subaxial subluxation (n = 6). An abnormal soft-tissue signal was noted in the preodontoid space in six patients; this signal was thought to represent the associated inflammatory mass. MR imaging was useful not only for depicting the bony abnormalities in the cervical spine that are associated with rheumatoid arthritis, but also can directly show the effect of the disease process on the spinal cord and brain stem.     

寰枢椎后路三种组合固定技术治疗寰枢关节不稳的临床评估

目的 评估寰枢椎后路三种组合固定技术治疗C1～2不稳的临床疗效和应用价值.方法 2002年8月至2008年3月,采用不同方法治疗寰枢关节不稳68例.(1)采用寰枢椎后路椎弓根螺钉技术治疗32例,其中AndersonⅡ型齿状突骨折20例(陈旧骨折7例,新鲜骨折13例),Ⅲ型新鲜齿状突骨折6例,寰椎横韧带断裂4例,先天性游离齿突并寰枢椎不稳2例;(2)采用经寰椎后弓椎弓根螺钉联合枢椎椎板螺钉固定治疗20例,其中AndersonⅡ型齿状突骨折伴寰枢关节向后脱位8例,向前脱位4例,齿状突骨折不愈合2例,Ⅲ型齿状突骨折伴寰枢关节不稳3例,寰枢关节前脱位伴横韧带断裂3例;(3)对16例创伤性寰枢椎不稳经牵引已达复位的可复型及经口前路松解后牵引复位的难复型寰枢椎脱位患者,采用经颈后路Apofix椎板夹和C1～2关节突螺钉内固定联合自体髂骨植骨治疗.结果 (1)采用寰枢椎后路椎弓根螺钉技术治疗32例患者共置入寰枢椎椎弓根螺钉120枚,其中有3例在置入寰椎椎弓根螺钉时,因后弓细小发生破裂,改用寰椎侧块固定.术中无一例发生脊髓和椎动脉损伤.术后CT显示2例一侧枢椎椎弓根螺钉部分进入椎动脉孔,另1例枢椎螺钉偏内致椎弓根内侧皮质破裂,均无症状,未发现与螺钉有关的神经血管损伤并发症.32例患者均获随访6～42个月,平均26个月.术后JOA评分13.2～16.8分,平均14.8分.无内固定松动或断钉现象,均已达到骨性融合.(2)采用寰椎经后弓椎弓根螺钉联合枢椎椎板螺钉固定治疗20例患者共置入枢椎椎板螺钉32枚,枢椎椎板螺钉位于椎板中,无偏斜.术中无一例发生脊髓和椎动脉损伤.20例随访6～14个月,平均11.2个月.术后X线片未见明显颈椎不稳、无内固定松动或断钉现象,均获得了良好的骨性愈合.(3)16例难复型寰枢椎脱位患者症状均有所改善,无神经症状加重表现.无神经血管损伤等并发症发生.16例随访8～26个月,平均16个月,所有患者在3～6个月均获得骨性融合.术后脊髓功能改善优5例,良8例,有效2例,无变化1例,无加重患者.内置物无松动、断裂.结论 寰枢椎后路三种组合固定技术是治疗上颈椎疾患的有效方法,具有固定牢固、固定节段短和三维固定的优点,在临床应用可根据患者的具体病情组合固定.     

Dermal grafts of the temporomandibular joint: postoperative appearance on MR images

Complications may follow meniscectomy and placement of an allogenic implant in temporomandibular joint (TMJ) dysfunction. To characterize the anatomy of autogenous dermal grafts for repair and repositioning of the meniscus, the authors performed T1-weighted magnetic resonance (MR) imaging of 20 TMJs in 10 patients 6-23 months after surgery that was considered successful. MR imaging did not enable detection of the dermal grafts. Comparison of preoperative and postoperative MR images revealed little, if any, change in meniscal position. MR images of 20 menisci revealed anterior displacement (n = 11), normal position (n = 4), focal areas of increased signal intensity (n = 4), fragmentation (n = 2), and suboptimal visualization (n = 5). MR images of 20 condyles revealed normal features (n = 11), erosions (n = 2), early avascular necrosis (AVN) or subchondral cysts (n = 2), AVN (n = 3), an osteophyte (n = 1), and loss of bone (n = 2). One TMJ demonstrated increased soft tissue in the bilaminar zone.