MR imaging of ankylosing spondylitis

Ankylosing spondylitis (AS) is one of a group of disorders characterized by association with HLA-B27 histocompatibility complex, seronegativity for rheumatoid factor, and propensity for inflammation at entheses, synovial articulations, and cartilaginous articulations. The radiographic hallmark of the disease is ankylosis, and the principle sites of involvement are the sacroiliac joints and spine, with less frequent involvement of other joints, including the pubic symphysis, hips, shoulders, knees, hands, feet, and sternoclavicular, acromioclavicular, sternomanubrial, and temporomandibular joints. Following a brief discussion of the basic pathophysiology and typical clinical findings of AS, we describe the typical magnetic resonance imaging features of the disease as it is manifests in the axial skeleton. Finally, a brief mention of special considerations in the radiographic evaluation of the AS patient in the setting of trauma is made.     

Cauda equina syndrome complicating ankylosing spondylitis: MR features

A case of cauda equina syndrome complicating long standing ankylosing spondylitis is presented. Bony erosions were demonstrated on CT. Magnetic resonance showed arachnoid diverticula filling the erosions. Magnetic resonance obviated the need for intrathecal contrast medium injection.     

Cervical spine fractures in ankylosing spondylitis: MR findings

Purpose: The purpose of this study is to evaluate the MR findings in patients with long-term ankylosing spondylitis (AS) and acute cervical spine fractures. Materials and methods: The magnetic resonance imaging (MRI) studies of five patients with AS and acute cervical spine fractures were retrospectively reviewed for the presence of cervical spine instability, spinal cord compression, and epidural hematoma. Results: Spinal fractures were unstable in all five patients. Three patients had neurological symptoms and abnormal signal within the spinal cord. All patients with neurological deficits had epidural hematomas posterior to the dural sac. Conclusion: MRI is useful for assessment of the integrity of intervertebral disks and spinal ligaments and, therefore, of the instability of the spinal fracture. MRI is mandatory in patients with neurological symptoms, especially in those with a symptom-free interval and those with neurological deterioration after established spinal cord injury, when suspicion for epidural hematoma is high. Electronic Publication     

强直性脊柱炎MRI诊断的价值.

强直性脊柱炎(AS)是一种以中轴关节慢性炎症为主的全身性疾病,常导致脊柱韧带广泛骨化而致骨性强直,致残率极高。早期诊断和及时治疗对评估病灶具有非常重要的意义。MRI对关节滑膜及受累骨的急、慢性炎症的显示较平片及CT具有优越性,其能很好地显示病变的受累部位、程度,并可判断病变的活动性。综述AS的MRI检查序列、MRI表现及评分标准。     

"Dural tail sign": a specific MR sign for meningioma?

Somewhat conflicting reports have appeared about the significance of linear meningeal thickening and enhancement adjacent to peripherally located cranial mass lesions on contrast enhanced magnetic resonance images. Some authors consider this finding nearly diagnostic of meningioma. In an attempt to determine the specificity of this so-called tail sign, particularly with respect to meningioma, we retrospectively reviewed 16 cases from institutional records. From our results, the tail sign appears to be highly suggestive but not specific for meningioma.     

MR imaging features of foot involvement in ankylosing spondylitis

OBJECTIVE: To determine alterations of the soft tissue, tendon, cartilage, joint space, and bone of the foot using magnetic resonance (MR) imaging in ankylosing spondylitis (AS) patients. MATERIALS AND METHOD: Clinical and MR examination of the foot was performed in 23 AS patients (46 feet). Ten asymptomatic volunteers (20 feet) were studied on MR imaging, as a control group. MR imaging protocol included; T1-weighted spin-echo, T2-weighted fast-field echo (FFE) and fat-suppressed short tau inversion recovery (STIR) sequences in sagittal, sagittal oblique, and coronal planes using a head coil. Specifically, we examined: bone erosions, tendinitis (acute and chronic), para-articular enthesophyte, joint effusion, plantar fasciitis, joint space narrowing, soft tissue edema, bone marrow edema, enthesopathy in the Achilles tendon and plantar fascia attachment, subchondral signal intensity abnormalities (edema and sclerosis), tenosynovitis, retrocalcaneal bursitis, subchondral cysts, subchondral fissures, and bony ankylosis. Midfoot, hindfoot, and ankle were included in examined anatomic regions. RESULTS: Clinical signs and symptoms (pain and swelling) due to foot involvement were present in 3 (13%) of the patients while frequency of involvement was 21 (91%) with MR imaging assessment. The MR imaging findings were bone erosions (65%), Achilles tendinitis (acute and chronic) (61%), para-articular enthesophyte (48%), joint effusion (43%), plantar fasciitis (40%), joint space narrowing (40%), subchondral sclerosis (35%), soft tissue edema (30%), bone marrow edema (30%), enthesopathy of the Achilles attachment (30%), subchondral edema (26%), enthesopathy in the plantar fascia attachment (22%), retrocalcaneal bursitis (22%), subchondral cysts (17%), subchondral fissures (17%), tendinitis and enthesopathy of the plantar ligament (13%), and bony ankylosis (9%). The most common involved anatomical region was the hindfoot (83%) following by midfoot (69% ) and ankle (22%). CONCLUSION: In our experience, MR imaging may detect inflammatory and/or erosive bone, soft tissue, cartilage, tendon, and joint abnormalities in AS patients, even if AS patients did not have clinical signs and symptoms of foot involvement. If these data prove to be confirmed in further MR studies, MR imaging may be of importance especially in early diagnosis of inflammatory changes in the foot.     

Cervical fracture in ankylosing spondylitis: value of multidimensional imaging.

Ankylosing spondylitis creates a rigid spinal column that cannot easily accommodate to altered or increased forces. Fractures or fracture-subluxation may be seen following apparently trivial injury. Assessment of the lower cervical and cervicothoracic spine can be limited in the kyphotic, ankylosed spine. However, reformatted computed tomography (CT) data can be manipulated to provide true orthogonal (sagittal, coronal) planar images of the obliqued spine, and can be used to provide a three-dimensional overview of anatomy prior to treatment. One such case is presented.     

Contrast-enhanced MR angiography of subclavian steal syndrome: value of the 2D time-of-flight "localizer" sign

OBJECTIVE: Our objective was to determine if direction of flow within the vertebral artery could be reliably determined by evaluation of flow-sensitive, low-resolution 2D time-of-flight (TOF) localizer images taken before 3D contrast-enhanced MR angiography (3D CEMRA) sequences in patients with unsuspected subclavian steal syndrome. CONCLUSION: Vertebral artery patency on 3D CEMRA in cases in which the vessel is absent on the TOF localizer in association with ipsilateral subclavian artery stenosis indicates reversal of flow in the vertebral artery and confirms the subclavian steal phenomenon. The combination of anatomic imaging with 3D CEMRA with functional information provided by the low-resolution TOF localizer confirms the diagnosis of subclavian steal without additional imaging.     

强直性脊柱炎骶髂关节病变CT扫描的诊断价值

目的 分析强直性脊柱炎(AS)之骶髂关节病变的影像学表现，评价CT对AS骶髂关节病变的诊断价值方法分析研究30例成人临床肯定的AS骶髂关节病变的影像学表现。结果 AS骶髂关节病变的早期影像学表现是首发于骶髂关节前下方滑膜处的骨质侵蚀。对此处病变的检出率CT明显高于平片。平片可疑病变CT基本可以确诊，同时分级更为精确。结论 CT能清晰显示骶髂关节的微细结构，对AS的早期征象敏感性较平片高，CT检查对早期病变的诊断有较高的价值。     

Vertebral body corner oedema vs gadoliniumenhancement as biomarkers of active spinal inflammation in ankylosing spondylitis

Objective To investigate the relative performance of T(2) weighted short tau inversion-recovery (STIR) and fat-suppressed T(1) weighted gadolinium contrast-enhanced sequences in depicting active inflammatory lesions in ankylosing spondylitis (AS). Methods Whole-spine MRI was performed on 32 patients with AS, who participated in a clinical trial of infliximab treatment, by STIR and contrast-enhanced sequences at baseline and after 30 weeks. The AS spine MRI-activity (ASspiMRI-a) scoring method was used. The images from these two imaging techniques were evaluated separately by two independent readers. Results For the pre-treatment lesion status, the intraclass correlation coefficients comparing STIR readings and contrast-enhanced readings were 0.69±0.23 for Reader 1 and 0.65±0.21 for Reader 2. At baseline, the mean ASspiMRI-a score was 15.4% and 17.7% higher for contrast-enhanced images than for STIR images for Reader 1 and Reader 2, respectively. After infliximab treatment, Reader 1 rated an ASspiMRI-a score reduction of 50.8±33.6% and 25.3±35.3% for STIR images and contrast-enhanced images, respectively, whereas Reader 2 rated an ASspiMRI-a score reduction of 42.4±50.4% and 32.9±35.6% for STIR images and contrast-enhanced images, respectively. Conclusion While both contrast-enhanced and STIR sequences showed sensitivity to change over a short period of time after infliximab treatment, these two sequences may reflect different disease mechanisms.     

多层螺旋CT在强直性脊柱炎骶髂关节病变中的应用价值

目的:探讨多层螺旋CT在强直性脊柱炎(AS)骶髂关节病变的应用价值。方法:56例临床确诊为强直性脊柱炎患者行骶髂关节多层螺旋CT检查,观察骶髂关节病变的CT表现及影像学特征。结果:强直性脊柱炎骶髂关节病变的多层螺旋CT表现特征为病变主要累及骶髂关节的髂骨侧,表现为关节软骨钙化、关节面毛糙、骨性关节面下多发小囊状骨质吸收、破坏伴不同程度骨质增生硬化,骶髂关节间隙狭窄、消失、关节骨性融合及骶髂韧带钙化等。结论:多层螺旋CT对强直性脊柱炎(AS)骶髂关节病变的诊断与鉴别诊断具有重要的应用价值。     

下行性强直性脊柱炎1例

患者女性，60岁，以右上肢及左下肢肌肉萎缩无力伴疼痛4a近期加重就诊，摄颈椎正侧双斜位片，观察颈椎椎间孔情况，拍片过程中，发现患者为驼背，颈部抬起困难。于是加照胸、腰椎正侧位及骨盆正位。     

MR功能成像对早期强直性脊柱炎骶髂关节的定量评估

目的：探讨联合应用T2*mapping T2*值和扩散加权成像(DWI)的表观扩散系数(ADC)值定量评估骶髂关节炎性活动性的可行性。方法将30例强直性脊柱炎(AS)根据病情严重程度按临床病情活动指数(BASDAI)评分,分为急性期 A组(17例)和慢性期B组(13例),另选健康志愿者C组(20例),行骶髂关节常规 MR扫描、T2*mapping及DWI,分别测量骶髂关节骨髓水肿区及相对正常区域的T2*值和 ADC值,并对3组间的均值差异和A、B组与BASDAI评分关系进行统计分析。结果 A组的T2*值和ADC值均大于B组和C组,差异有统计学意义(P<0.05);B组的T2*值和ADC值与C组对比,无统计学差异(P>0.05);A、B组T2*值和 ADC值与临床BASDAI评分呈正相关性(P<0.05)。结论联合应用T2*mapping 和DWI有助于 AS早期诊断并定量分析骶髂关节炎性活动性程度。     

强直性脊柱炎核素关节显像

目的 探讨^99Tc^m-人免疫球蛋白（HIgG)与99Tc^m-亚甲基二膦酸盐（MDP）关节显像在强直性脊柱炎（AS）中的应用价值。方法 对经确诊的21例AS和18例活动期类风湿关节炎（RA）患者行^99Tc^m-HIgG全身显像，其中12例AS患者行^99Tc^m-MDP显像。结果 ①21例AS患者中20例^99Tc^m-HIgG显像示骶髂关节异常放射性增高；44个有临床症状或体征的外周关节中，32个显像异常，临床符合率75％，无一例累及手部小关节。②18例活动期RA患者^99Tcm-HIgG显像均有手部关节的异常改变，无一例累及骶髂关节。③12例AS患者^99Tc^m-HIgG与^99Tc^m-MDP显像比较显示：前者有11例骶髂关节异常放射性分布增高，而后者显像异常仅7例。31个临床累及的外周关节中，^99Tc^m-HIgG显像阳性24个，^99Tc^m-MDP显像异常16个，与临床符合率分别为77．4％和51．6％，差异有显著性（P＜0．025）。结论 ^99Tc^m-HIgG显像能较^99Tc^m-MDP显像更为准确地探测AS患者病变关节的炎症改变，帮助临床早期明确诊断。     

Diagnostic value of diffusion weighted magnetic resonance image in early ankylosing spondylitis

Background

Diffusion-weighted MRI (DW-MRI) shows the early changes in microscopical movement of water molecules, hence diagnosis of early sacroiliitis which is one of the diagnostic criteria of seronegative spondyloarthropathies.

Objective

To determine the value of DW-MRI in detection of signal characteristics of the sacroiliac joints in patients with early ankylosing spondylitis (AS).

Patients and methods

Fifteen patients with clinically suspected AS, 20 patients with mechanical low back pain and 20 healthy controls underwent conventional MRI and DWI. Apparent diffusion coefficient (ADC) was measured. In addition ten clinically confirmed AS patients underwent whole body-DWI.

Results

Mean ADC values of both sacroiliac joints in AS patients were (0.523 ± 0.15) × 10⁻³ mm²/s in the ilium and (0.502 ± 0.15) × 10⁻³ mm²/s in the sacrum. There was no significant difference between mechanical LBP and healthy controls. But there was a significant difference between AS and LBP patients. Mean ADC value of focal lesions of clinically confirmed AS was 0.965 ± 0.25 × 10⁻³ mm²/s in the sacrum and 0.932 ± 0.31 × 10⁻³ mm²/s in the ilium.

Conclusion

Subchondral bone marrow ADC values of sacroiliac joints allow differentiation between inflammatory and mechanical LBP. Furthermore, it may be helpful in evaluating the efficacy of the treatment and determine disease prognosis.     

Spondyloarthropathies: ankylosing spondylitis and psoriatic arthritis

As advances in the treatment of ankylosing spondylitis continue, TNF-alpha blocking agents may eventually be used as a first-line treatment. MR imaging could then be used to aid in the early diagnosis of ankylosing spondylitis by identifying early sacroiliitis, followed by immediate initiation of treatment to prevent the progression of the disease with its accompanying morbidities. Currently, radiographic identification of sacroiliitis remains the mainstay in diagnosing ankylosing spondylitis. In ankylosing spondylitis and psoriasis, MR imaging can demonstrate areas that are undergoing active inflammatory changes and enthesitis, aiding in the diagnosis of a spondyloarthropathy.