A comparison of functional MR activation patterns during silent and audible language tasks.

PURPOSETo compare word generation tasks performed silently and aloud as paradigms for functional MR.METHODSImages were obtained at 1.5 T, with echoplanar acquisition in nine subjects performing word generation aloud or silently. Functional images created from the echoplanar images by means of cross-correlation techniques were superimposed on anatomic reference images. The location of activation from the two tasks was tabulated; the number of activated pixels in each region from the two tasks was compared.RESULTSBoth silent and aloud word generation produced activation in the inferior frontal lobes, sensorimotor cortex regions, supplementary motor areas, and anterior cingulate gyri, predominantly in the dominant hemisphere. Significantly more activated pixels and fewer artifacts were detected with silent word generation than with word generation aloud.CONCLUSIONWord generation silently or aloud produce activation in the brain. Greater activation can be detected in the left frontal lobe with silent word generation, although the subject''s performance of the task cannot be monitored independently during silent word generation.     

Knee-muscle activation during landings: developmental and gender comparisons

PURPOSE: This study determined anteroposterior knee-joint muscle activation differences among children and adult males and females landing from a self-initiated vertical jump (VJ) under normal and offset-target conditions to further understand physical maturation's influence on anterior cruciate ligament (ACL) injury risk. METHODS: Fifty-five recreationally active volunteer subjects grouped by age (children = 9.5 +/- 0.9 yr; adult = 23.9 +/- 2.8 yr) and gender (females = 28; males = 27) completed motion analysis, ground reaction force, and surface electromyography (SEMG) data collection during a two-footed landing under straight (midline-target) and offset-target (adult = 45.7 cm; child = 30.5 cm) conditions. Target height was 50% of maximum VJ height. Co-contraction ratios (CCR) (hamstrings (HAMS)/vastus medialis (VM) activity) from normalized SEMG root mean squares were analyzed in the prelanding (PRE) (100 ms before initial contact (IC)), reflexive (REF) (100 ms after IC), and voluntary (VOL) (end of REF to maximum knee flexion) muscle activity phases. Repeated-measures statistical analyses determined significant gender, physical maturation, and target differences (P < 0.05) in CCR and associated HAMS and VM activity across landing phases. RESULTS: A significant interaction (P < 0.0001) indicated similar CCR for children and adults during the REF and VOL phases, but during the PRE phase adult CCR (619.04 + 52.01) were two times greater than children's (308.32 +/- 51.04). Significantly more HAMS activity, not less VM activity, increased adult PRE-CCR. Gender and target CCR differences were absent. CONCLUSIONS: Children's decreased preparatory co-contraction about the knee does not seem to be linked to increased ACL injury risk. Thus, adults may strive for preparatory co-contraction levels about the knee that permit adaptability to varied landing tasks.     

The influence of caffeine on voluntary muscle activation

Caffeine is a very common CNS stimulant that has been of interest to physiologists because of its direct effects on skeletal muscle in vitro, as well as ergogenic effects on laboratory tests of human performance. While in vitro studies have clearly demonstrated the effects of the drug on the CNS, the effects of caffeine on the voluntary activation of muscle in humans are less defined. Voluntary as well as involuntary supraspinal input, alpha motor neuron membrane properties, and afferent feedback to spinal and supraspinal neurons all modulate voluntary muscle activation, and caffeine may therefore alter muscle activation at several sites along the motor pathway. This review explores the effects of caffeine on voluntary muscle activation that have been demonstrated in recent human studies and discusses the central mechanisms that may enhance activation. Evidence of caffeine's effects on the motor evoked potential, Hoffman reflex, self-sustained firing of the alpha motor neuron, and pain and force sensation are presented as well as limitations and considerations of using the drug in human neuromuscular studies.     

The influence of gender and menstrual phase on thermosensitivity during cold water immersion

BACKGROUND: This investigation evaluated the influence of gender and phase of menstrual cycle [follicular (FOL: days 2-6) and luteal (LUT: days 19-24) phases] on thermosensitivity and metabolic heat production (HP) during cold water immersion (20 degrees C) in 10 females (22.4 +/- 2.8 yr) and 16 males (22.4 +/- 2.9 yr). METHODS: Following a 20-min baseline period (BASE), subjects were immersed until esophageal temperature (Tes) reached 36.5 degrees C or for a maximum pre-occlusion (Pre-OCC) time of 40 min. An arm and thigh cuff were then inflated to 180 and 220 mmHg, respectively, for 10 min (OCC). Following release of the inflated cuffs (Post-OCC), the slope (beta) of the relationship between the decrease in Tes and the increase in HP was used to quantify thermosensitivity. RESULTS: ANOVA revealed no significant difference in thermosensitivity between phases of the menstrual cycle or between men and women (FOL = -2.76, LUT = -3.05, Males = -3.24 W x kg(-1) x degrees C(-1)). A significant (p < 0.05) main effect for gender for HP, and a significant (p < 0.05) main effect for menstrual phase for mean skin temperature (Tsk) were observed. CONCLUSIONS: These data suggest, despite gender differences in HP, that the thermosensitivity of HP during cold water immersion is similar between males and females and is not influenced by menstrual cycle phase. Therefore, these data indicate that when faced with a cold challenge, women respond similarly to men in both phases of their menstrual cycle.     

The effects of auditory rhythms and instruction on walking patterns in individuals post stroke

The objective was to investigate the effects of auditory rhythms and arm movement on inter-segmental coordination during walking in persons who have suffered a stroke. Eleven subjects walked on a treadmill: (1) during systematic increases in velocity (0.22-1.52 m/s), (2) with instructions to 'step to the beat' during systematic increases in metronome frequency (1-2.2 Hz), and (3) with instructions: 'move the arms and legs to the beat' during systematic increases in metronome frequency (1-2.2 Hz). Movement amplitude of upper and lower body segments, frequency coordination between arm and leg movements, phase relation between upper and lower body segments were measured. Moving the arms and legs to the beat resulted in increased arm swing along with 1:1 frequency coordination between the arm and leg, and a more out-of-phase relation between transverse pelvic and thoracic rotation was observed with larger pelvic and thoracic rotations. Verbal instructions to move the arms to the beat of a metronome leads to increased arm swing, increased stride length, but further study is needed to examine the dynamics of the changes in arm movement, to enhance understanding of how upper extremity movement dysfunction affects inter-segmental coordination during walking.     

Pharmacologic influence on esophageal varices: A preliminary report

Selective catheterization of the left gastric vein was performed after percutaneous transhepatic portography (PTP) in patients with portal hypertension and esophageal varices. Following the hypothesis that drugs increasing the lower esophageal sphincter (LES) pressure may obstruct the variceal blood flow through the lower esophagus, the effect of different drugs (i.e., intravenous injection of vasopressin, pentagastrin, domperidone and somatostatin and subcutaneous injection of metacholine) on the variceal blood flow was examined. Vasopressin did not change the variceal blood flow; pentagastrine, with its known effect of increasing the LES pressure produced a total interruption of the flow in four of eight patients; domperiodone, also known to increase the LES pressure obstructured the variceal blood flow in the only patient examined with this drug; somatostatin has no reported action on the LES but blocked the flow in one of two patients; and metacholine, reported to increase the LES pressure did not produce any change in the flow in the three patients examined. LES pressure was recorded before and during vasopressin infusion in seven patients with portal hypertension and esophageal varices. No reaction on the pressure was found. The patient number in the study is small and the results are nonuniform but still they suggest that drugs increasing the LES tonus might be useful to control variceal blood flow.     

Improvement of auditory hallucinations and reduction of primary auditory area's activation following TMS

Background

In the present case study, improvement of auditory hallucinations following transcranial magnetic stimulation (TMS) therapy was investigated with respect to activation changes of the auditory cortices.

Methods

Using functional magnetic resonance imaging (fMRI), activation of the auditory cortices was assessed prior to and after a 4-week TMS series of the left superior temporal gyrus in a schizophrenic patient with medication-resistant auditory hallucinations.

Results

Hallucinations decreased slightly after the third and profoundly after the fourth week of TMS. Activation in the primary auditory area decreased, whereas activation in the operculum and insula remained stable.

Conclusions

Combination of TMS and repetitive fMRI is promising to elucidate the physiological changes induced by TMS.     

糖尿病与高血压对老年性聋患者听觉功能影响

目的探讨高血压、糖尿病对老年性聋患者听觉功能的影响。方法在2015年4月至2016年4月于南京市第一医院就诊的老年性聋患者中随抽取60例作为研究对象。其中,伴糖尿病者、伴高血压者、同时伴糖尿病及高血压者以及不伴任何慢性性疾病者各15例,分别组成糖尿病组(DM组)、高血压组(HA组)、高血压及糖尿病组(HA+DM组)及对照组(GC组)。对全部研究对象进行耳部检查、声导抗检测及纯音听阈测试,采用ANOVA检验对各组患者250~8 000 Hz频率的听力阈值进行统计分析。结果 DM组及HA组患者的高频(频率>2 000 Hz)听阈较GC组高,差异均有统计学意义(P<0.05);HA+DM组全频听阈均明显高于GC组,且高频(频率>2 000 Hz)听阈比DM组及HA组高,差异均有统计学意义(P<0.05)。结论高血压和糖尿病可能是加重老年性聋的重要因素,积极治疗高血压和糖尿病是防治老年性聋的重要手段。     

局灶性脑皮质发育不良的扩散张量成像初步研究

目的 探讨DTI技术诊断局灶性脑皮质发育不良(FCD)的价值.方法 回顾性分析12例FCD患者的临床、MRI及DTI等资料.DTI经过图像后处理,获得平均扩散系数(MD)和部分各向异性分数(FA)图及彩色编码张量图,于FCD的皮质下白质区及对侧相应皮质下白质区设置椭圆形ROI,测量每个ROI的MD及FA值.病灶侧与对侧MD、FA值的比较采用配对t检验.扩散张量纤维束示踪成像(DTT)以T_2 WI图像为参照,ROI设置同DTI,以ROI中的任一点作为种子点,获得通过该ROI区域的所有白质纤维束示踪图像.结果 12例患者MR平扫均显示局灶性脑皮质增厚及灰白质界限不清,其中7例显示皮质下白质稍长T_1、稍长T_2信号,2例皮质下白质萎缩,3例皮质下白质无明显异常.DTI分析显示FCD邻近皮质下白质与对侧比较FA值明显下降(患侧0.31±0.05,对侧0.42±0.08,t=-3.995,P<0.01),MD值明显上升[患侧(1.02±0.16)×10~(-3)mm~2/s,对侧(0.86±0.13)×10~(-3) mm~2/s,t=2.655,P<0.05],差异均有统计学意义.DTT显示10例FCD患者皮质下白质纤维束较对侧明确减少,2例较对侧可能减少,主要表现为皮质下白质纤维稀疏,与深部白质纤维间联系减少.结论 FCD除了导致脑皮质结构异常外,也影响局部皮质下白质纤维的发育,DTI是常规MR检查的重要补充.     

The influence of female gender on the outcome of endovascular abdominal aortic aneurysm repair

PURPOSE: Women appear to have a greater risk of death than men after open surgery for abdominal aortic aneurysm (AAA). The aim of this study is to compare outcomes after endovascular AAA repair in men and women. MATERIALS AND METHODS: From March 1994 to November 2000, 305 patients (281 men and 24 women) underwent AAA repair with use of endovascular techniques. Outcomes measured included perioperative mortality, percentage of procedures aborted or converted to open abdominal AAA repair, deployment success rate, angiographic success rate, major complication rate, and percentage of patients with endoleaks. RESULTS: Patients of both genders were comparable with respect to mean age (74.4 in men vs 75.9 in women; NS). According to the Society for Vascular Surgery/International Society of Cardiovascular Surgery risk stratification method, men and women were also comparable in age risk score (0.60 vs 0.67; NS), pulmonary risk score (0.50 vs 0.83; NS), and renal risk score (0.28 vs 0.17; NS). However, the cardiac risk score was higher in men (1.31 vs 0.80; P <.05) and maximum AAA diameter was greater in men (57.0 mm vs 52.1 mm; P <.01). Eight perioperative deaths (2.6%) occurred (2.8% of men, 0% of women; NS). Proportionately more procedures were aborted in women than men: four (16.7%) versus six (2.1%; P <.01). Conversion to open repair occurred in four men (1.4%) and no women (NS). Deployment success was achieved in 96.4% of men and 83.3% of women (P <.01). Angiographic success was achieved in 84.1% of men and 80% of women (NS). Of 46 major complications, 42 (14.9%) occurred in 281 men and four (16.7%) occurred in 24 women (NS). Sixty-seven patients had endoleaks: 60 were men (22.1%) and seven were women (35%; NS). CONCLUSIONS: There was no difference between men and women with respect to perioperative mortality and major complication rates. These findings indicate that being a woman does not adversely influence the outcome of endovascular AAA repair. However, women had a higher rate of aborted procedures. Precise preoperative evaluation may help reduce this problem in women.     

Brain activation in sedated children: auditory and visual functional MR imaging

PURPOSE: To map developing areas of activation with functional magnetic resonance (MR) imaging in sedated children by using passive auditory and visual tasks. MATERIALS AND METHODS: Forty children between 2 months and 9 years old were examined and grouped according to age. Children were selected from patients referred to undergo brain MR imaging. Patients received pentobarbital (3.0-7.0 mg per kilogram of body weight) or chloral hydrate (50-75 mg/kg). The functional MR imaging study was performed at the end of the examination. Paradigms consisted of flashing lights at 8 Hz displayed on special goggles and a prerecorded mother's voice presented through headphones. Activation maps were obtained from a paired t test with a P value of.0005 (uncorrected). RESULTS: The visual stimulus produced statistically significant negative values in the rostral aspect of the primary visual area (28 [90%] of 31 patients). The auditory paradigm activated either temporal or frontal areas in 26 (68%) of 31 patients. There was more frontal activation in the older children. CONCLUSION: Visual and auditory cortices can be activated in children who have been sedated. Visual responses show negative values in the rostral visual cortex, independent of age. Auditory activation is seen in temporal and frontal lobes.     

Computed tomographic patterns of pseudohypertrophic muscular dystrophy: preliminary results

At present, the diagnosis of pseudohypertrophic muscular dystrophy (PHMD) rests on the clinical picture and the pattern of inheritance and is supported by electrodiagnostic, histologic, and histochemical techniques. In this report we describe the observed computed tomography (CT) changes in six patients with PHMD and compare these abnormal CT scans with scans of the same anatomic region in 16 normal individuals. Scans of patients with polymyositis and sarcoid myopathy are shown for comparison. Two CT patterns, frequently observed in our series, are described.     

Asymmetry and gender effect in functionally lateralized cortical regions: a proton MRS imaging study

PURPOSE: to compare metabolite concentrations and ratios in gray matter regions known for their anatomical/functional asymmetry and evaluate gender effect. MATERIALS AND METHODS: Proton MRS imaging was performed at 1.5 T with TR/TE 2300/280 msec in 20 healthy right-handed subjects (mean age 29.6 +/- 5.3 years, 10 men). Concentrations of N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr), and the peak area ratios NAA/Cho, NAA/Cr, and Cho/Cr were evaluated in hippocampal and parahippocampal gyri, thalamus, insula, Broca's and Wernicke's areas (and corresponding contralateral areas), primary and secondary visual areas, temporal, inferior parietal, cingulate, supplemental motor, dorsolateral prefrontal, and sensorimotor areas. Linear mixed-effects regression models were used for statistical analyses. RESULTS: NAA concentration and NAA/Cho were higher in the left thalamus by 21.9% and 20%, respectively (both P < 0.001). NAA concentration was 13% higher in the region contralateral to Wernicke's area (P < 0.02). No gender differences were found. CONCLUSION: Metabolite concentrations and ratios were symmetric and gender independent in most brain regions, however small hemispheric side differences in the thalamus and in Wernicke's area were found.     

DWI评价TURP手术对前列腺不同组织影响的初步研究

目的:应用EPI-DWI评价TURP手术对前列腺不同组织弥散特性的影响,对DWI在疗效观察中的应用进行初步探讨。方法:分析46例经病理组织学证实的的前列腺癌病例,其中10例为TURP手术组,对照组为36例。使用GE E-cho-speed 1.5 T超导成像仪,联合应用盆腔相控阵线圈和直肠内表面线圈,DWI采用单次激发EPI进行扫描。标出前列腺癌、BPH和正常前列腺周围带的感兴趣区,计算其大小及体积及X、Y和Z轴三个方向计算ADC值,并由工作站处理产生ADC图。结果:前列腺癌TURP手术组分级、分期及大小体积高于非手术组(P<0.05)。前列腺相同组织的ADCx值在手术组与非手术组之间无显著差异(P值分别>0.05)。结论:TURP手术有促进前列腺癌进展的可能性;DWI及ADC值能准确地对TURP手术后前列腺癌做出诊断,但不能用于TURP术后评价。     

Comparison of MRI and renal cortical scintigraphy findings in childhood acute pyelonephritis: preliminary experience

OBJECTIVE: The diagnosis of acute pyelonephritis in children remains a clinical challenge. It may cause permanent renal scar formation and results in the chronic renal failure if prompt diagnosis and treatment are delayed. The purpose of this study is to compare magnetic resonance imaging (MRI) and renal cortical scintigraphy (RCS) findings in childhood acute pyelonephritis and to determine pyelonephritic foci in the acute phase. MATERIALS AND METHOD: Twenty children (15 females and five males) with symptoms dysuria, enuresis, costovertebral pain, fever of 37.5 degrees C or more and/or positive urine culture were imaged by unenhanced turbo spin echo T2, spin echo T1-weighted, pre- and post-gadolinium inversion recovery MRI and RCS. Both imaging techniques were read independently by two radiologists and nuclear medicine specialists. Sensitivity and specificity of MRI in detecting acute pyelonephritic foci and scar lesions were calculated. Furthermore, in order to calculate the reliability of MRI over RCS in differentiating scar tissue and acute pyelonephritic foci, follow-up MRI studies were done in six patients after treatment of acute pyelonephritis. RESULTS: Sensitivity and specificity of MRI in the detection of pyelonephritic lesions were found to be 90.9 and 88.8%, respectively. There is no statistically significant difference in lesion detection between the two diagnostic modalities (P>0.05). CONCLUSION: Post-gadolinium MR images show significant correlation with RCS in the determination of renal pathology. Moreover, the ability of discriminating acute pyelonephritic foci and renal scar in early stages of disease is the superiority of MRI.