Cartilage destruction in small joints by rheumatoid arthritis: assessment of fat-suppressed three-dimensional gradient-echo MR pulse sequences in vitro

Purpose. To assess the accuracy of different MR sequences for the detection of articular cartilage abnormalities in rheumatoid arthritis. Design and patients. Ten metacarpophalangeal joints and 10 metatarsophalangeal joints (specimens from arthritis patients undergoing ablative joint surgery) were examined with a fat-suppressed (FS) 3D FLASH, a FS 3D FISP, a FS 2D fast spin-echo T2-weighted, and a 2D FS spin-echo T1-weighted sequence. Each cartilage lesion and each cortical lesion was graded from 0 to 4 (modified Outerbridge staging system). Subsequently, the results of each sequence were compared with the macroscopic findings and statistically tested against each other. Results. The study shows that 3D gradient-echo sequences with fat suppression were best for imaging and grading of cartilage lesions in arthritis of the small joints of the hands and feet. Using 3D techniques, all grade 2, grade 3, and grade 4 lesions of cartilage or cortical bone were detected. Conclusion. FS 3D gradient-echo techniques were best for the detection and grading of hyaline cartilage and subchondral bone lesions in rheumatoid arthritis. MRI has a great potential as an objective method of evaluating cartilage damage and bone erosions in rheumatoid arthritis.     

MR imaging of viscoelastic properties

Mechanical waves in magnetic resonance imaging, which have been suggested for possible clinical applications, were analyzed with regard to imaging of the viscoelastic properties of large objects. The method is based on the Larmor frequency modulation caused by the application of mechanical waves. Possible clinical applications include all diseases that result in a change in the mechanical properties of biologic tissues (eg, atherosclerosis).     

Correct positioning for cardiac angiography: Insights from mri

The recommended angiographic projections for optimally demonstrating various cardiac structures vary, and do not always achieve their aim. To determine the most appropriate radiographic projections to optimally demonstrate cardiac structures, we reviewed the orientations of major cardiac structures and the associated great vessels, as demonstrated by axial MRI. Measurements were made from 187 MRI examinations of the heart. These measurements confirmed that the optimum angiographic projections for various cardiac structures are at variance with a number of the recommended views. Recommendations for the angiographic projections most likely to provide optimum display of various cardiac structures and associated great vessels in different patient populations are presented. © 1993 Wiiey-Liss, Inc.     

Effects of exercise on muscle activation and metabolism in multiple sclerosis

We investigated the role of metabolism in muscle fatigue during voluntary exercise in persons with mild multiple sclerosis (MS). Six MS and 8 healthy control subjects performed intermittent, progressive, isometric contractions of the ankle dorsiflexors, during which we measured maximum voluntary force (MVC), inorganic phosphate (Pi), phosphocreatine (PCr), and pH. During exercise. MVC fell sooner in MS, but by the end of exercise the relative decrease in MVC was similar in both groups. In contrast, at the end of exercise Pi/PCr increased to 1.86 ± 0.22 in controls but to only 0.66 ± 0.04 in MS (P < 0.01); likewise, pH was 6.75±0.04 in controls and unchanged (7.06 ± 0.04) in MS (P <0.01). The smaller metabolic change at the same relative exercise intensity suggests a failure of muscle activation that is present even in mild MS. Neurophsyiologic measures of activation indicated some central activation failure and no neuromuscular junction impairment in MS, and suggested that activation failure beyond the muscle membrane(excitation–contraction coupling) may be important in MS. We conclude that metabolic factors do not play a significant role in the development of muscle fatigue during voluntary exercise in mild MS. © 1994 John Wiley & Sons, Inc.     

Evaluation of loose bodies in the elbow with MR imaging

The evaluation of loose bodies in the elbow is usually done by means of clinical examination, radiography, and postarthrographic computed tomography (CT). The authors review their experience with magnetic resonance (MR) imaging in place of postarthrographic CT for the evaluation of loose bodies in the elbow. The prospective interpretation of MR studies of the elbow in 20 patients was compared with arthroscopic findings. All elbows were imaged in multiple planes with thin sections, surface coils, and combinations of T1, T2, and proton-density weighting. The sensitivity for showing loose bodies with MR imaging was 100%, and the specificity was 67%. Because this was a nonblinded study, the results are biased and caution must be used when extrapolating these results to the general population. In this limited experience, MR imaging has reliably shown loose bodies in the elbow, and in the authors' institutions has replaced postarthrographic CT for that purpose.     

P-31 MR spectroscopy of skeletal and cardiac muscle metabolism in patients with systemic sclerosis: A multiple case study

Three-dimensionally localized proton-decoupled phosphorus-31 magnetic resonance (MR) spectroscopy of skeletal and cardiac muscle was performed in six patients with systemic sclerosis. Cardiac (n = 9) and skeletal (n = 6) spectra were also obtained in healthy volunteers. Metabolite ratios and intracellular pH were determined from the spectra of skeletal and cardiac muscle. The phosphocreatine-to-adenosine triphosphate ratio was normal for both skeletal and cardiac muscle in patients with systemic sclerosis. The pH values of skeletal muscle were similar in patients and control subjects (7.13 ± 0.02 vs 7.12 ± 0.01, respectively). In skeletal muscle, the inorganic phosphate-to-phosphocreatine ratio in patients was increased relative to that of control subjects (0.106 ± 0.014 vs 0.086 ± 0.006, respectively; P =.02). P-31 MR spectroscopy showed no abnormalities in the myocardium of patients with systemic sclerosis. Assessment of the inorganic phosphate-to-phosphocreatine ratio in peripheral skeletal muscle may be helpful for assessing disease activity.     

Applications of magnetic resonance spectroscopy to diagnosis and monitoring of mitochondrial disease

Magnetic resonance spectroscopy (MRS) can now be performed on routine high-field clinical magnetic resonance imaging systems. Over the last decade it has provided several useful insights into the pathophysiology of mitochondrial disorders. More recently, the feasibility of applications to clinical diagnosis and monitoring have been demonstrated. Exciting new work suggests that carefully supervised physical conditioning in conjunction with sodium dichloroacetate administration can markedly enhance both biochemical measures of aerobic metabolism and functional performance of patients with mitochondrial myopathies.

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Sommario La risonanza magnetica spettroscopica (MRS) può oggi essere effettuata di routine in apparecchi clinici di risonanza magnetica. Nell'ultima decade essa ha fornito importanti informazioni nella patofisiologia dei disordini mitocondriali. Più recentemente sono state dimostrate le sue possibilità di applicazione nella diagnosi clinica e nel monitoraggio di pazienti neurologici. Nuovi ed interessanti studi suggeriscono che un allenamento attentamente supervisionato in congiunzione con trattamento con dicloroacetato è capace di migliorare i parametri biochimici e la performance di pazienti con miopatie mitocondriali.

     

10%水合氯醛在小儿MR扫描应用中的护理体会

<正>磁共振已成为一种安全、可靠、无创伤、无X线福射,适用于小儿的影像学检查方法。但此项检查时间长、噪声大,且需患儿在整个扫描过程中都要保持安静,稍有躁动便会引起伪影,影响图像成像质量。为此,我院自2000年6月至2006年12月对6岁以下不合作的儿童给予10%水合氯醛口服或灌肠后行MR扫描,均取得了满意效果。现将用10%水合氯醛在小儿MR检查扫描应用中的护理体会总结如下。     

不同状态胆囊组织的傅立叶变换红外光谱研究

目的 探索不同生理病理状态的胆囊组织各自特异的傅立叶变换红外光谱(Fourier transform infrared spectroscopy，FT-IR)表现。方法 应用FT-IR对8例正常胆囊组织、10例炎性胆囊组织和10例胆囊癌组织进行检测，结合常规病理结果总结不同组织的光谱特征。结果 胆囊正常、炎性和癌组织具有不同的FT-IR光谱表现，1550cm^-1处的酰胺Ⅱ带在癌组织中显得较弱，峰形低平，而在正常组织中则较强，峰形高尖。1080cm^-1处核酸的吸收谱带在癌组织中较强，I1080／I1550的比值在正常组织中为0．62，癌组织中为0．87。正常组织中1450cm^-1处的峰多强于1400cm^-1处，而在癌组织中则相反。结论 胆囊正常、炎性和癌组织的FT-UR谱图不同，主要表现为组织中蛋白质、核酸和磷脂等含量与结构的改变，FT-IR有望成为胆道疾病临床诊断的一种新手段。