磁共振成像在多发性肌炎、皮肌炎诊断中的应用

目的 研究多发性肌炎(PM)、皮肌炎(DM)的磁共振成像(MRI)表现，评价MRI在PM及DM诊断中应用价值。方法 对5例PM及4例DM患者行MRI检查，选择骨盆、双侧大腿及小腿肌肉，采用自旋回波序列(SE)、快速自旋回波序列(FSE)及短时反转恢复序列(STIR)进行扫描。结果 5例PM及4例DM患者的受累肌群均表现为斑片状等T1长T2异常信号，2例PM患者尚可见小斑片状短T1长T2异常信号影；6例患者肌筋膜增厚，呈长T2线样高信号改变；4例DM患者的表皮及皮下结缔组织尚可见条带状及网格状长T1长T2异常信号影。受累肌群主要表现为炎症水肿样改变，晚期受累肌肉可见少量脂肪替代改变；病变双侧不对称，以内收肌受累最重，股中间肌受累最轻。结论 PM与DM患者的MRI表现具有一定的特征性，MRI能为PM及DM的定位诊断、疗效判断及病情随访提供客观资料，并能为临床选取准确的活检部位提供帮助。     

炎性肌病的诊断与鉴别诊断

炎性肌病是一类由免疫介导或直接由病原体感染所引起的骨骼肌的炎性病变。广义而言，它包括多发性肌炎（PM）、皮肌炎（DM）、无肌病性皮肌炎（amyopathic dermatomyositis，ADM）、包涵体肌炎（IBM）、嗜酸性筋膜炎、局灶性肌炎、肉芽肿性肌炎和感染性肌病，其中感染性肌病又可分为病毒性肌炎、寄生虫性肌炎、细菌性肌炎、真菌性肌炎和支原体肌炎等；而从狭义上来讲，炎性肌病仅指多发性肌炎、皮肌炎、无肌病性皮肌炎和散发性包涵体肌炎。除了包涵体肌炎外，其他炎性肌病均为可治愈性或可控制性疾病，因此对其早期诊断和及时治疗显得尤为重要。然而，炎性肌病并非l临床常见的神经系统疾病，尤其在不典型的情况下漏诊或误诊时有发生。因此，笔结合自己的l临床体会．就炎性肌病的诊断与鉴别诊断总结概述。[第一段]     

少年特发性炎性肌病的研究进展

少年特发性炎性肌病(JIIMS)主要包括少年皮肌炎(JDM)、少年多发性肌炎(JPM)和少年包涵体肌炎.作为炎性肌病的一类,因少见而对其知之较少,本文将对JIIMS的流行病学、诊断标准、临床特点、治疗、疾病活动的评估和监测以及发病机制等方面最新研究进展进行综述.     

包涵体肌炎的诊断标准

散发性包涵体肌炎 (ｓｐｏｒａｄｉｃｉｎｃｌｕｓｉｏｎｂｏｄｙｍｙｏｓｉｔｉｓ,ｓＩＢＭ)是一种好发于中、老年人 ,以缓慢进行性肌无力和肌萎缩为主要临床特点的炎性肌肉疾病[1 ,2 ] ,常被误诊为激素不敏感的多发性肌炎。目前世界各国对包涵体肌炎有不同的诊断标准。与国外报道的大量病例相比 ,我国迄今为止仅见少数病例报道[3 5] ,其原因可能与对此病还缺乏足够的认识 ,以及肌肉活检的冰冻切片技术尚不普及有关。为了提高大家对包涵体肌炎的诊断水平 ,2 0 0 1年 5月 1 0～ 1 5日中华医学会神经病学分会神经肌肉病学组在浙江省杭州市萧…     

特发性炎性肌病的蛋白组学研究进展

特发性炎性肌病主要包括皮肌炎、多发性肌炎和散发性包涵体肌炎,该类肌病发病机制未明确,用于临床诊断的特异性抗体缺乏。使用蛋白组学研究数据虽然较少,但有所发现。皮肌炎主要与氧化应激相关蛋白有关,多发性肌炎多与炎症、线粒体功能障碍和氧化磷酸化通路异常相关,而散发性包涵体肌炎不仅与氧化应激、线粒体功能障碍、炎症相关,还与变性相关。本文就蛋白质组学在特发性炎性肌病目前的研究做一综述。     

MELAS型线粒体脑肌病的MRI诊断

目的探讨合并乳酸血症和卒中样发作的线粒体脑肌病（MELAS）的磁共振成像（MRI）影像学特点。方法收集经临床病理证实的MELAS型线粒体脑肌病共6例,回顾性分析其MRI和磁共振波谱（MRS）资料。结果脑MRI检查,MELAS表现为大脑半球各叶大小不等片状病灶;病变位于脑皮质区,病灶的分布与脑血供分布不一致;自旋回波T1加权像呈低信号、T2加权像呈高信号;扩散加权成像（DWI）呈高信号。MRS分析显示病灶区见典型的乳酸盐峰,N-乙酰天门冬氨酸盐,肌酸值正常或略降低。扩散张量成像（DTI）显示病灶区脑皮质下白质纤维束破坏、中断、稀少。结论MELAS型线粒体脑肌病的病变形态、分布具有特征性,常规MRI与DWI、DTI及MRS等磁共振技术,对MELAS的定性诊断具有很高的价值。     

包涵体肌炎11例临床及组织病理报告

目的探讨包涵体肌炎的诊断标准.方法分析了11例包涵体肌炎病人的临床表现、组织化学.碱性刚果红染色 9例,电镜检查2例.结果全部病人均在42岁后发病,表现为远、近端肌肉力弱,2例肌电图检查显示肌源性改变,11例均有边缘着色性空泡及炎性改变,9例有淀粉样蛋白沉积物,有胞核或胞质细丝包涵体各1例.结论包涵体肌炎的所有诊断指标中,无一项有决定性或特征性,需要进行综合判断.     

磁共振成像液体衰减反转恢复序列高信号血管征研究进展

磁共振成像(magnetic resonance imaging,MRI)液体衰减反转恢复序列(fluid-attenuated inversion recovery,FLAIR)技术是1992年Hajnal等首先研制开发并命名的一种MRI技术.其基本原理是在自旋回波或梯度回波序列前附加一个180°反转脉冲,抑制在常规磁共振T2加权序列(T2-weighted image,T2WI)中表现为高信号的脑脊液,增加T2权重,突出病灶的显示.     

磁共振成像液体衰减反转恢复序列高信号血管征研究进展

磁共振成像(magnetic resonance imaging,MRI)液体衰减反转恢复序列(fluid-attenuated inversion recovery,FLAIR)技术是1992年Hajnal等首先研制开发并命名的一种MRI技术.其基本原理是在自旋回波或梯度回波序列前附加一个180°反转脉冲,抑制在常规磁共振T2加权序列(T2-weighted image,T2WI)中表现为高信号的脑脊液,增加T2权重,突出病灶的显示.     

磁共振成像液体衰减反转恢复序列高信号血管征研究进展

磁共振成像(magnetic resonance imaging,MRI)液体衰减反转恢复序列(fluid-attenuated inversion recovery,FLAIR)技术是1992年Hajnal等首先研制开发并命名的一种MRI技术.其基本原理是在自旋回波或梯度回波序列前附加一个180°反转脉冲,抑制在常规磁共振T2加权序列(T2-weighted image,T2WI)中表现为高信号的脑脊液,增加T2权重,突出病灶的显示.     

Inclusion body myositis: Clinical and pathological boundaries

Inclusion body myositis, polymyositis, and dermatomyositis are three distinct categories of inflammatory myopathy. Some authorities commented on the selective early weakness of the volar forearm muscles, quadriceps, and ankle dorsiflexors in inclusion body myositis. The most important feature distinguishing inclusion body myositis from the other two inflammatory myopathies is the lack of responsiveness to immunosuppressive treatment. Although most patients with inclusion body myosities have characteristic muscle biopsy findings, some cannot be distinguished histologically early from polymyositis. Presdicting responsiveness to mmunosuppressive medications, independent of muscle histology, would be valuable to clinicians. We retrospectively reviewed the pattern of weakness and other clinical features of 46 patients newly diagnosed with either inclusion body myositis, polymyositis, or dermatomyosities. Asymmetrical muscle weakness with prominent wrist flexor, finger flexor, and knee extensor involvement was specific for inclusion body myositis and unresponsive polymyositis. Male sex, lower creatine kinase levels, slower rate of progression, and peripheral neuropathy were also more common in inclusion body myositis and unresponsive polymyositis than in responsive polymyositis and dermatomyositis patients. Repeat muscle biopsy in 2 patients in teh unresponsive polymyositis group demonstrated histological features of inclusion body myositis. We suspect that patients with clinical features of inclusion body myositis but lacking histological confirmation may nonetheless have inclusion body myositis. Our study supports the recently proposed criteria for defintie and possible inclusion body myositis.     

Monoclonal antibody analysis of mononuclear cells in myopathies. I: Quantitation of subsets according to diagnosis and sites of accumulation and demonstration and counts of muscle fibers invaded by T cells

In 76 muscle specimens (normal controls, 9; Duchenne dystrophy, 11; scleroderma, 11; dermatomyositis, 13; polymyositis, 15; inclusion body myositis, 17), mononuclear cells were analyzed at perivascular, perimysial, and endomysial sites of accumulation. Monoclonal antibodies reactive for B cells, T cells, T cell subsets, killer (K) or natural killer (NK) cells, and the Ia antigen were used for cell typing. Macrophages were identified by the acid phosphatase reaction. Few extravascular mononuclear cells occurred in normal muscle. In all inflammatory myopathies, a mixed exudate of T cells, B cells, and macrophages was present. Mature K/NK cells were rare in all diseases. In dermatomyositis, polymyositis, and inclusion body myositis, there was a positive gradient for T cells, T8+ cells, and activated T cells and a negative gradient for B cells and T4+ cells between perivascular and endomysial sites. In scleroderma the predominant perimysial exudate consisted mostly of T cells and macrophages. The percentage of B cells at all sites, and the T4+/T cell ratio in the endomysium, were significantly higher in dermatomyositis than in the other diseases. In polymyositis and inclusion body myositis, the endomysial exudate contained a large number of T cells, T8+ cells, and activated T cells but only sparse B cells. T cells accompanied by macrophages focally surrounded and invaded nonnecrotic fibers in polymyositis and inclusion body myositis. Rare fibers in Duchenne dystrophy and a very few fibers in dermatomyositis and scleroderma were similarly affected. We infer that (1) T-B, T-T, and T-macrophage cooperativities are likely to exist in muscle in different myopathies; (2) T cell-mediated fiber injury plays a role in polymyositis and inclusion body myositis; (3) T cell-mediated fiber injury can also occur in inherited diseases, such as Duchenne dystrophy; and (4) a local humoral response may occur in muscle in dermatomyositis and possibly in polymyositis and inclusion body myositis.     

Coculture with autologous myotubes of cytotoxic T cells isolated from muscle in inflammatory myopathies.

T-cell lines were expanded from muscle of 10 patients with polymyositis, 5 with inclusion body myositis, 5 with dermatomyositis, and 5 with other muscle diseases. All cell lines uniformly expressed T-cell antigens, but not natural killer cell or B-cell antigens. The proportion of helper (CD4+) and cytotoxic (CD8+) T cells in the expanded lines was variable and showed no correlation with the diagnosis. Sixteen cell lines (6 polymyositis, 4 inclusion body myositis, 5 dermatomyositis, 1 other muscle disease) consisted predominantly of CD8+ T cells. None of these lines displayed natural killer-like cytotoxicity but all were capable of lectin-dependent cytotoxicity. Three of 6 polymyositis, 1 of 4 inclusion body myositis, and 1 of 5 dermatomyositis lines showed low but statistically significant cytotoxicity against autologous myotubes (6 to 27% specific 51Cr release; effector-target ratio, 20:1). The results demonstrate that functionally competent cytotoxic T cells can be expanded from muscle affected by inflammatory myopathies and are consistent with the hypothesis that some cytotoxic T cells recognize an autoantigen on myotubes. Further studies of this experimental system may define the molecular mechanism of T cell-mediated muscle fiber injury and may help to identify the relevant antigens.     

Rimmed vacuoles and the added value of SMI-31 staining in diagnosing sporadic inclusion body myositis

Problems in diagnosing sporadic inclusion body myositis may arise if all clinical features fit a diagnosis of polymyositis, but the muscle biopsy shows some rimmed vacuoles. Recently, immunohistochemistry with an antibody directed against phosphorylated neurofilament (SMI-31) has been advocated as a diagnostic test for sporadic inclusion body myositis. The aims of the present study were to define a quantitative criterion to differentiate sporadic inclusion body myositis from polymyositis based on the detection of rimmed vacuoles in the haematoxylin-eosin staining and to evaluate the additional diagnostic value of the SMI-31 staining. Based on clinical criteria and creatine kinase levels in patients with endomysial infiltrates, 18 patients complied with the diagnosis of sporadic inclusion body myositis, and 17 with the diagnosis of polymyositis. A blinded observer counted the abnormal fibres in haematoxylin-eosin-stained sections and in SMI-31-stained sections. The optimal cut-off in the haematoxylin-eosin test was 0.3% vacuolated fibres. Adding the SMI-31 staining significantly increased the positive predictive value from 87 to 100%, but increased the negative predictive value only to small extent. We conclude that (1) patients with clinical and laboratory features of polymyositis, including response to treatment, may show rimmed vacuoles in their muscle biopsy and that (2) adding the SMI-31 stain can be helpful in differentiating patients who respond to treatment from patients who do not.     

Contrast-enhanced Ultrasound in Dermatomyositis- and Polymyositis

Objective To evaluate prospectively contrast-enhanced ultrasound (CEUS) in patients suspected of having dermatomyositis or polymyositis. Methods In 35 patients (23 women, 12 men; mean age, 51 years ± 16 years) who were suspected of having dermatomyositis or polymyositis, perfusion in clinically affected skeletal muscles was quantified with contrast-enhanced intermittent power Doppler ultrasound. By applying a modified model that analyzed the replenishment kinetics of microbubbles, the perfusion-related parameters blood flow, local blood volume and blood flow velocity were measured. Findings were compared with muscle biopsy appearances and with the results of MRI that was performed with a 1.5-Tesla unit. Receiver operating characteristic analysis was performed and optimum thresholds for diagnosis of myositis were determined. Results Eleven patients had histologically confirmed dermatomyositis or polymyositis and showed significantly higher blood flow velocity (P = .01 for dermato- and P < .001 for polymyositis), blood flow (P < .001 for dermato- and polymyositis), and blood volume (P = .007 for dermato- and P < .001 for polymyositis) on contrast-enhanced ultrasound than those who did not have myositis. An increase in signal intensity on T2-weighted MR images was found in all patients with myositis. MRI had a sensitivity, specificity, positive (PPV), and negative predicting values (NPV) of 100%, 88%, 77%, and 100% for diagnosis of myositis, respectively. CEUS blood flow was the best ultrasound measure for diagnosis of dermato- or polymyositis with sensitivity, specificity, PPV, and NPV of 73%, 91%, 80%, and 88%, respectively. Conclusions Increased skeletal muscle perfusion measured by CEUS could serve as an additional measurer for the diagnosis of an inflammatory myopathy. Received in revised form: 6 June 2006 An erratum to this article is available at .     

Inclusion body myositis mimicking motor neuron disease

OBJECTIVE: To describe the clinical and electrophysiologic features of patients with inclusion body myositis that was misinterpreted as motor neuron disease. PATIENTS AND METHODS: We retrospectively retrieved the medical records of 70 patients with a pathologic diagnosis of inclusion body myositis. From this group, we selected those who had been first diagnosed as having motor neuron disease or amyotrophic lateral sclerosis. We reviewed the clinical, electrophysiologic, laboratory, and morphologic studies. RESULTS: Nine (13%) of 70 patients with inclusion body myositis had been diagnosed as having motor neuron disease. Six of the 9 patients had asymmetric weakness; in 4 the distal arm muscles were affected. Eight patients had finger flexor weakness. Tendon reflexes were preserved in weak limbs in 6, hyperactive in 2, and absent in 1. Four patients had dysphagia. Fasciculation was seen in 2 patients. None had definite upper motor neuron signs or muscle cramps. Routine electromyographic studies showed fibrillation potentials and positive sharp waves in all 9. Fasciculation potentials were seen in 7 and long-duration polyphasic motor unit potentials were seen in 8. There was no evidence of a myogenic disorder in these 9 patients. Muscle biopsy was done because of slow progression or prominent weakness of the finger flexors and was diagnostic of inclusion body myositis. A quantitative electromyogram was myopathic in 4 of the 5 patients studied. CONCLUSIONS: Inclusion body myositis may mimic motor neuron disease. Muscle biopsy and quantitative electromyographic analysis are indicated in patients with atypical motor neuron disease, especially those with slow progression or early and disproportionate weakness of the finger flexors.     

Treatment of idiopathic inflammatory myopathies

PURPOSE OF REVIEW: This article reviews the results of recent therapeutic trials in dermatomyositis, polymyositis, and inclusion body myositis and suggests an approach to treating patients with inflammatory myopathy. RECENT FINDINGS: We reviewed 10 double-blind, placebo-controlled therapeutic trials in patients with inflammatory myopathy. Only one, using intravenous immunoglobulin in refractory dermatomyositis, indicated benefit. A brief trial of azathioprine in polymyositis and eight studies using various treatments in inclusion body myositis did not show benefit. SUMMARY: There have been no adequate double-blind, placebo-controlled therapeutic trials of dermatomyositis and polymyositis. It is generally accepted, however, that these disorders respond to immunosuppressive agents. Prednisone is usually the initial treatment. There is no agreement on how prednisone should be administered and even less agreement about other agents. Inclusion body myositis, which now appears to be the most common (in adults), is unresponsive to immunosuppressive and immunomodulating therapies. There are candidate treatments for inclusion body myositis and a need for additional double-blind, placebo-controlled therapeutic trials in all patients with inflammatory myopathy.     

Inclusion body myositis (IBM). Morphological study.

Among the chronic idiopathic inflammatory myopathies inclusion body myositis (IBM) has emerged as a clinicopathologic variant. Slowly progressive weakness of the distal and the proximal muscle groups, the presence of rimmed vacuoles with basophilic granules as well as 15-18-nm filamentous inclusions in affected muscle confirm the clinical and histopathological distinction between inclusion body myositis and chronic polymyositis.     

Magnetic resonance imaging of skeletal muscles in idiopathic inflammatory myopathies of adults

The purpose of the study was to describe typical MRI findings in various types of idiopathic inflammatory myopathies in adulthood and to correlate the MRI with histopathological and electromyographic findings, and the serum creatine kinase (CK) activity. A third goal was to assess the diagnostic value of the use of gadolinium-DTPA (Gd-DTPA). Fifty-eight patients (35 women, 23 men), aged 21–83 years (median age 59 years), suffering from idiopathic myositides (13 with acute and 45 chronic diseases; 25 with polymyositis, 14 with dermatomyositis, 8 with granulomatous and 11 with inclusion body myositides) were examined with MRI. Seventeen of them received an intravenous infusion of Gd-DTPA. Histopathological and MRI findings of 21 muscles of 18 patients were compared. MRI of skeletal muscles showed abnormal signal intensities in 56 (96.6%) of the 58 patients. MRI abnormalities were found more often than elevated CK activity (P < 0.001). The hyperintensity of T2-weighted images was more conspicuous than on T1-weighted images in 26 (44.8%) patients, indicating oedema-like abnormalities. MRI of 50 (86.2%) patients showed fat replacement. In acute myositides, oedema-like abnormalities were more often visible and in muscle lipomatosis less often visible than in chronic diseases (P < 0.05 each). In dermatomyositis oedema-like abnormalities were more and lipomatosis less frequent than in the other types of myositis (P < 0.005) and correlated with the acuteness of the disease. In 3 of 17 patients in whom contrast-enhanced T1-weighted images were obtained in addition to plain T1- and T2-weighted images, T2-weighted images were more sensitive in the detection of oedema-like abnormalities than the contrast-enhanced T1-weighted images. In no patient was the opposite true. Thus, contrast-enhanced T1-weighted images did not provide more information than T2-weighted images. Nine patients with poly-, dermato- and inclusion body myositis showed clearly asymmetrical findings. Imaging of the thighs and legs was of similar sensitivity. The different types of myositides showed typical but not specific distributions of the mesenchymal abnormalities in MRI. The findings indicate that MRI of skeletal muscles in myositides can visualize the presence and distribution of oedema-like abnormalities and intramuscular lipomatosis and is suitable for the assessment of the chronicity and severity of the disease.