Therapeutic effect of repetitive transcranial magnetic stimulation on motor function in Parkinson''s disease patients

Cortical excitability of the primary motor cortex is altered in patients with Parkinson's disease (PD). Therefore, modulation of cortical excitability by high frequency repetitive transcranial magnetic stimulation (rTMS) of the motor cortex might result in beneficial effects on motor functions in PD. The present study aims to evaluate the effect of rTMS of the motor cortex on motor functions in patients with PD. Thirty-six unmedicated PD patients were included consecutively in this study. The patients were assigned in a randomized pattern to one of two groups, one group receiving real-rTMS (suprathreshold 5-Hz, 2000 pulses once a day for 10 consecutive days) and the second group receiving sham-rTMS using closed envelopes. Total motor section of Unified Parkinson's Disease Rating Scale (UPDRS), walking speed, and self-assessment scale were performed for each patient before rTMS and after the first, fifth, 10th sessions, and then after 1 month. Evaluation of these measures was performed blindly without knowing the type of rTMS. anova for repeated measurements revealed a significant time effect for the total motor UPDRS, walking speed and self-assessment scale during the course of the study in the group of patients receiving real-rTMS (P = 0.0001, 0.001, and 0.002), while no significant changes were observed in the group receiving sham-rTMS except in self-assessment scale (P = 0.019). A 10-day course of real-rTMS resulted in statistically significant long-term improvement of the motor functions in comparison with the sham-rTMS. The rTMS could have a therapeutic role of for PD patients.     

SPIR扫描在诊断骨胳肌肉系统疾病中的应用

目的：探讨SPIR脂肪抑制技术在骨胳肌肉系统疾病MRI检查中的诊断价值。材料与方法：对36例骨、关节软组织疾病患者行T1W／SE、T2W／FSE及T2W／SPIR序列扫描，并对后两者进行比较。结果：各种病理性积液呈高信号；损伤性骨髓水肿呈高信号；骨折线呈低信号，如骨折断端出血则呈线状高信号；软组织肿瘤囊性部分呈高信号，实质部分呈中等强度信号；软组织炎症性病变为弥漫性高信号；骨病成骨性改变为低信号；骨髓病变为高信号或混杂等高信号；椎管内占位性病变及半月板损伤SPIR显示不清。结论：SPIR能提高正常组织与病变组织间的对比度，清晰地显示病变组织，作为T1W／SE、T2W／FSE序列的辅助检查，有助于提高骨胳肌肉系统疾病的诊断水平。     

MRI同层动态增强对垂体微腺瘤的诊断价值

目的：分析垂体微腺瘤的MPd同层动态增强特征。方法：对40例临床怀疑为垂体微腺瘤的病人行同层动态增强MPd扫描，并绘出时间一信号强度曲线图。结果：40例病人中共检出垂体微腺瘤26例。同层动态增强后垂体微腺瘤的MPd表现为圆或椭圆形的低或稍低信号，似“充盈缺损”；垂体微腺瘤的最大信号强度多出现在注入造影剂后32～96s，以64s最明显。结论：同层MPd动态增强对垂体微腺瘤的诊断有较高价值。     

Three-dimensional biomechanical properties of the human rectum evaluated with magnetic resonance imaging

A method to evaluate the three-dimensional (3-D) geometry of the human gastrointestinal wall may be valuable for understanding tissue biomechanics, mechano-sensation and function. In this paper we present a magnetic resonance imaging (MRI) based method to determine rectal geometry and validation of data obtained in three volunteers. A specially designed rectal bag was filled in a stepwise manner while MRI and bag pressure were recorded. 3-D models of curvatures, radii of curvature, tension and stress were generated and the circumferential and longitudinal strains were calculated. The computed bag volumes corresponded to the infused volumes. A pronounced bag elongation and decrease in wall thickness was observed during the bag filling. The spatial distributions of the biomechanical parameters were distinctly different between individuals and non-homogeneous throughout the rectal wall due to its complex geometry. The average tension and stress increased as a function of infused volume and circumferential strain. The present study provides a method for characterizing the complex in vivo 3-D geometry of the human rectum. The non-homogenous spatial curvature distribution suggests that simple estimates of tension based on pressure and volume do not reflect the true 3-D biomechanical properties of the rectum.     

Assessment of myocardial viability in rats: Evaluation of a new method using superparamagnetic iron oxide nanoparticles and Gd-DOTA at high magnetic field.

The aim of this study was to detect salvageable peri-infarction myocardium by MRI in rats after infarction, using with a double contrast agent (CA) protocol at 7 Tesla. Intravascular superparamagnetic iron oxide (SPIO) nanoparticles and an extracellular paramagnetic CA (Gd-DOTA) were used to characterize the peri-infarction zone, which may recover function after reperfusion occurs. Infarcted areas measured from T1-weighted (T1-w) images post Gd-DOTA administration were overestimated compared to histological TTC staining (52% +/- 3% of LV surface area vs. 40% +/- 3%, P=0.03) or to T2-w images post SPIO administration (41% +/- 4%, P=0.04), whereas areas measured from T2-w images post SPIO administration were not significantly different from those measured histologically (P=0.7). Viable and nonviable myocardium portions of ischemically injured myocardium were enhanced after diffusive Gd-DOTA injection. The subsequent injection of vascular SPIO nanoparticles enables the discrimination of viable peri-infarction regions by specifically altering the signal of the still-vascularized myocardium.     

Electrodynamics and ultimate SNR in parallel MR imaging.

The purpose of this article is to elucidate inherent limitations to the performance of parallel MRI. The study focuses on the ultimate signal-to-noise ratio (SNR), which refers to the maximum SNR permitted by the electrodynamics of the signal detection process. Using a spherical model object, it is shown that the behavior of the ultimate SNR imposes distinct limits on the acceleration rate in parallel imaging. For low and moderate acceleration, the ultimate SNR performance is nearly optimal, with geometry factors close to 1. However, for high reduction factors beyond a critical value, the ultimate performance deteriorates rapidly, corresponding to exponential growth of the geometry factor. The transition from optimal to deteriorating performance depends on the electrodynamic characteristics of the detected RF fields. In the near-field regime, i.e., for low B0 and small object size, the critical reduction factor is constant and approximately equal to four for 1D acceleration in the sphere. In the far-field wave regime the critical reduction factor is larger and increases both with B0 and object size. Therefore, it is concluded that parallel techniques hold particular promise for human MR imaging at very high field.     

On information field of clinical diagnosis

“Field” is a universal phenomenon existing in both nature and society, and determines the existence and significance of all materials or information. The man being has always been generating and carrying a large quantity of life information in his whole life. Each piece of life information has an independent information field. The life information field includes such three subfields as bioinformation field, psychoinformation field and psycho-bioinformation field.The clinical diagnosis information field which is a specific information field within the information field of human activities consists of all information concerning man‘s health. Only after we have cognized and ascertained the clinic diagnosis information field, can we accurately utilize its function to serve the human being.     

A sexually dimorphic ratio of orbitofrontal to amygdala volume is altered in schizophrenia.

BACKGROUND: Neuroanatomic sexual dimorphisms have been correlated with behavioral differences between healthy men and women. We have reported higher orbitofrontal cortex to amygdala ratio (OAR) in women than men. Although gender differences in schizophrenia are evident clinically and correlate with neuroanatomic measures, their relationship to OAR has not been examined. METHODS: Magnetic resonance imaging was performed in 31 neuroleptic-na?ve schizophrenic patients (16 men) and 80 healthy volunteers (34 men), aged less than 50 years. An automated tissue segmentation procedure was combined with expert-guided parcellation of orbitofrontal and amygdala volumes. RESULTS: Men with schizophrenia had increased OAR relative to healthy men, whereas women had decreased OAR. Increased OAR in men with schizophrenia reflected abnormally low amygdala volumes, whereas decreased OAR in women reflected abnormally low orbitofrontal volumes. Less severe negative symptoms were associated with increased OAR in men but with decreased OAR in women. In men, increased amygdala volume was associated with greater symptom severity, whereas in women higher volumes of both amygdala and orbitofrontal regions were associated with lesser severity of negative symptoms. CONCLUSIONS: These opposite OAR abnormalities, whereby men show feminization and women masculinization, suggest gender-mediated effects of the underlying neuropathologic processes. The correlations with symptom severity suggest that neuroanatomic abnormalities in OAR reflect compensatory brain changes.     

ENDOSCOPY ASSISTED REMOVAL OF FERROMAGNETIC COINS WITH NOVEL MAGNETIC INSTRUMENT

Background: Ingestion of coins is a common clinical problem in children. Many of the coins are ferromagnetic and can be retrieved with the help of a magnet. We describe the use of a novel endoscopic accessory for removing ferromagnetic coins. Material and methods: Two magnet discs of 1.5 cm diameter were joined to a 200 cm steel wire of 0.75 mm thickness with a terminal 5 cm spring. A Teflon tube (160 cm, 7 F) was used along with this instrument as a sleeve. The use of this accessory was analyzed prospectively in subjects presenting with a history of coin ingestion. The time taken for removal of coins, complications during the procedure and failure rate was noted. Effect of the magnet on cardiac rhythm was also noted during the procedure. Results: A total of 55 children (mean age 5.1 ± 2.3 years) with coin ingestion presented over a period of 1 year. Forty‐four coins were ferromagnetic. All ferromagnetic coins were removed successfully. Mean time for removal was 68 ± 22 s. No complications were encountered. Conclusion: The novel magnetic instrument is precise, safe and quick for the removal of ferromagnetic coins under direct vision.     

Impaired modulation of motor cortex excitability by homonymous and heteronymous muscle afferents in focal hand dystonia.

A decrease of heteronymous median nerve-evoked inhibition of corticospinal projections to forearm extensor muscles was reported in a group of 10 dystonic patients by Bertolasi and colleagues in 2003. Here we tested the excitability of corticomotoneuronal connections to both wrist extensor (ECR) and flexor (FCR) muscles after conditioning stimulation of median and also radial nerve at rest in a group of 25 patients with focal hand dystonia compared to 20 healthy subjects. We also investigated the effect of the wrist dystonic posture, either in flexion or in extension, on the afferent modulation of ECR and FCR motor evolved potentials (MEPs). The heteronymous (median-induced) but also homonymous (radial-induced) inhibitions (interstimuli intervals 13-21 ms) of ECR MEP size observed in healthy subjects were decreased in patients. In addition, homonymous (median-induced) facilitation of FCR MEP size was also decreased in patients while heteronymous inhibition (radial-induced) was not. Neither the involvement of the target muscle in the dystonic posture nor the origin of the afferent volley (from a dystonic muscle) influenced the degree of impairment of afferent modulation of the MEP. These findings support the view that a global abnormal somatosensory coupling in focal hand dystonia may contribute to an inadequate motor command to wrist muscles.