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1.
ABSTRACT Diffusion tensor imaging (DTI) and quantitative T(2) magnetic resonance imaging (MRI) were used to characterize ex vivo the white matter damage at 3 and 8 weeks following dorsal column transection (DC Tx) injury at the cervical level C5 of rat spinal cords. Luxol Fast Blue (LFB) and myelin basic protein (MBP) staining was used to assess myelin damage, and neurofilament-H in combination with neuron specific beta-III-tubulin (NF/Tub) staining was used to assess axonal damage. Average values of myelin water fraction (MWF), fractional anisotropy (FA), longitudinal diffusivity (D(long)), transverse diffusivity (D(trans)), and average diffusivity (D(ave)) were calculated in the fasciculus gracilis, fasciculus cuneatus, and the dorsal corticospinal tract (CST) 5 mm cranial, as well as 5 and 10 mm caudal to injury and correlated with histology. These tracts were selected as these contain bundles of parallel ascending and descending axons in very circumscribed areas with little intermingling of other axonal populations. Axonal and myelin degeneration occur cranial to injury in the funiculus gracilis and caudal to injury in the CST. Both MWF and D(trans) showed significant correlation with LFB staining at 3 weeks (0.64 and -0.49, respectively) and 8 weeks post-injury (0.88 and -0.71, respectively). Both D(long) and FA correlated significantly with NF/Tub staining at 3 weeks post-injury (0.78 and 0.64, respectively), while only D(long) displayed significant correlation 8 weeks post-injury (0.58 and 0.33, respectively). This study demonstrates that quantitative MRI can accurately characterize white matter damage in DC Tx model of injury in rat spinal cord.  相似文献   

2.
The aim of the study was to compare the different approaches of pre-operative diffusion-tensor-imaging-based fibre tracking (FT) of the corticospinal tract (CST) focusing on the positioning of the seeding region of interest (seed ROI). Thirty-nine patients with brain lesions in the vicinity of the CST were evaluated pre-operatively. Imaging comprised a 3D T1-weighted sequence, a gradient echo echo-planar imaging sequence for functional magnetic resonance imaging (fMRI), and a diffusion-weighted sequence for diffusion tensor (DT) tractography. DT tractography was performed with two different procedures to track the corticospinal fibres: one downwards and one upwards. Downward FT was started with the seed ROI in the pre-central gyrus subjacent to the maximal fMRI activity while for the upward FT seed ROI was placed in the cerebral peduncle. In 16 patients, tracking results were individually compared with the unaffected contralateral hemisphere. Results were correlated with fractional anisotropy (FA) values and other factors potentially influencing fibre tracking results. On the side with the space-occupying lesion, downward FT yielded more positive tracking results (tracked fibres?>?0) than the upward FT. On both the affected and the unaffected side, downward FT reconstructed fewer fibres than upward FT. For none of the two methods did the tracking results (number and volume of fibres) correlate with FA values or with other clinical data. FA values for tracts ipsilateral to the lesion correlated with age and lesion entity. We conclude that the sequence of ROI positioning influences significantly the tracking results. Upward FT may fail to track fibres, whereas the successful tracking results may be superior to downward FT. Hence, upward FT of the CST should be preferred in patients with space-occupying lesions. Downward FT should be performed if upward FT fails.  相似文献   

3.
Despite negative neuroimaging findings in concussed athletes, studies indicate that the acceleration and deceleration of the brain after concussive impacts result in metabolic and electrophysiological alterations that may be attributable to changes in white matter resulting from biomechanical strain. In the present study we investigated the effects of sports concussion on white matter using three different diffusion tensor imaging (DTI) measures: fractional anisotropy (FA), mean diffusivity (MD), and axial diffusivity (AD). We compared a group of 10 non-concussed athletes with a group of 18 concussed athletes of the same age (mean age 22.5 years) and education (mean 16 years) using a voxel-based approach (VBA) in both the acute and chronic post-injury phases. All concussed athletes were scanned 1-6 days post-concussion and again 6 months later in a 3T Siemens Trio(?) MRI. Three 2×2 repeated-measures analyses of variance (ANOVAs) were conducted, one for each measure of DTI used in the current study. There was a main group effect of FA, which was increased in dorsal regions of both corticospinal tracts (CST) and in the corpus callosum in concussed athletes at both time points. There was a main group effect of AD in the right CST, where concussed athletes showed elevated values relative to controls at both time points. MD values were decreased in concussed athletes, in whom analyses revealed significant group differences in the CST and corpus callosum at both time points. Although the use of VBA does limit the analyses to large tracts, and it has clinical limitations with regard to individual analyses, our results nevertheless indicate that sports concussions do result in changes in diffusivity in the corpus callosum and CST that are not detected using conventional neuroimaging techniques.  相似文献   

4.
Diffusion Tensor Imaging (DTI) tractography has been used to detect leftward asymmetries in the arcuate fasciculus, a pathway that links temporal and inferior frontal language cortices. In this study, we more specifically define this asymmetry with respect to both anatomy and function. Twenty right-handed male subjects were scanned with DTI, and the arcuate fasciculus was reconstructed using deterministic tractography. The arcuate was divided into 2 segments with different hypothesized functions, one terminating in the posterior superior temporal gyrus (STG) and another terminating in the middle temporal gyrus (MTG). Tractography results were compared with peak activation coordinates from prior functional neuroimaging studies of phonology, lexical-semantic processing, and prosodic processing to assign putative functions to these pathways. STG terminations were strongly left lateralized and overlapped with phonological activations in the left but not the right hemisphere, suggesting that only the left hemisphere phonological cortex is directly connected with the frontal lobe via the arcuate fasciculus. MTG terminations were also strongly left lateralized, overlapping with left lateralized lexical-semantic activations. Smaller right hemisphere MTG terminations overlapped with right lateralized prosodic activations. We combine our findings with a recent model of brain language processing to explain 6 aphasia syndromes.  相似文献   

5.
The uncinate fasciculus interconnects the anterior temporal and inferior frontal lobes. The temporal lobes show a number of anatomical asymmetries, some of which are altered in schizophrenia. This study was performed to assess the size and symmetry of the uncinate fasciculus in normal subjects and in patients with the disorder. The area, fibre density and total fibre number of left and right uncinate fasciculi were estimated using stereological methods in 21 control subjects and 17 schizophrenics. The uncinate fasciculus was found to be asymmetrical in both sexes, being 27% larger and containing 33% more fibres in the right than the left hemisphere. Of the 25 brains from which both hemispheres were available, the size asymmetry was seen in 20 subjects and the greater number of fibres in 21 subjects. There was no significant effect of schizophrenia upon the uncinate fasiculus, nor interactions of diagnosis with side or sex. We conclude that the uncinate fasciculus is larger in the right hemisphere, perhaps indicating greater right-sided fronto-temporal connectivity. The unchanged size of the fasciculus in schizophrenia contrasts with commissural tracts, which are affected in this brain series in a sex-specific manner.  相似文献   

6.
目的为预测冠状动脉旁路移植术(CABG)后是否发生心房颤动(AF),对其术前危险因素进行分析。方法收集安贞医院2007年9月至2008年4月226例体外循环冠状动脉旁路移植术(CABG)或非体外循环冠状动脉旁路移植术(OPCAB)患者的临床资料,根据术后3d内是否出现AF持续5min以上分为非AF组和AF组,分析两组患者超声心动图检查指标及术前一般临床资料。两组患者均采用胸骨正中切口,并在相同条件下完成手术。结果术后24例患者(10.6%)发生AF.AF组中左心房前后径〉35mm的患者高于非AF组[41.7%(10例)vs.22.3%(45例),χ^2=4.380,P=0.036)];二尖瓣反流患者高于非AF组[37.5%(9例)vs.17.3%(35例),χ^2=5.568,P=0.018)];左主干病变患者高于非AF组[33.3%(8例)vs.12.4%(25例),χ^2=7.560,P=0.006];年龄AF组高于非AF组(65.7±9.5岁vs.60.1±10.1岁,t=-2.724,P=0.010)。两组患者单因素分析结果:高龄、二尖瓣反流、左心房大、左主干病变等手术前临床指标是术后发生AF的危险因素;手术后呼吸机使用时间(χ^2=4.190,P=0.040),心电监护时间(χ^2=5.948,P=0.015),住院费用(χ^2=4.110,P=0.043)等两组间比较差异有统计学意义。结论CABG后发生AF与高龄、二尖瓣反流、左心房增大、左主干病变等危险因素有关。临床资料、心电图、超声心动图检查等有助于预测CABG后是否发生AF,以使更好地预防和治疗,降低术后AF的发生率。  相似文献   

7.
8.
To prevent hypercalcemia in the treatment of secondary hyperparathyroidism, low calcium (L-Ca) dialysate is advocated. However, changes in ionized calcium (i-Ca) levels have a pivotal role in myocardial contraction and could influence blood pressure stability during dialysis. Recently, our group found in patients with normal cardiac function a significant decrease in blood pressure (decrease in systolic blood pressure [DSBP]: -13 mm Hg and decrease in mean arterial pressure [DMAP]: -7 mm Hg) during dialysis with L-Ca dialysate compared with high calcium (H-Ca) dialysate, and this was mainly related to a decreased left ventricular contractility with use of L-Ca dialysate. On the basis of these data, it could be expected that changes in i-Ca levels during dialysis are of more clinical importance in cardiac-compromised patients (CCpts), New York Heart Association classifications III and IV. In this study, the effects of L-Ca dialysate (1.25 mmol/L) and H-Ca dialysate (1.75 mmol/L) on arterial blood pressure parameters (systolic [SBP], diastolic [DBP], and mean arterial blood pressure [MAP]), heart rate, stroke distance (SDist), and minute distance (MDist) during 3 hours of a standardized ultrafiltration/hemodialysis (UF+HD) in nine CCpts was investigated. i-Ca levels increased significantly with H-Ca dialysate UF+HD, whereas there was no change with L-Ca dialysate. SBP, DBP, and MAP decreased statistically and clinically significantly during UF+HD with L-Ca dialysate and were significantly lower with the use of L-Ca dialysate compared with H-Ca dialysate. SDist and MDist decreased significantly with L-Ca dialysate, whereas there were no changes in SDist and MDist with H-Ca dialysate. The predialysis and postdialysis index of systemic vascular resistance (SVRI) was similar between L-Ca dialysate and H-Ca dialysate use. Between the two groups, there were no significant differences in changes in SVRI. From this study, we can conclude that changes in i-Ca levels are a very important determinant of the blood pressure response during UF+HD in CCpts, and this response is mediated by changes in myocardial contractility.  相似文献   

9.

Background Context

Hybrid surgery (HS), consisting of cervical disc arthroplasty (CDA) at the mobile level, along with anterior cervical discectomy and fusion at the spondylotic level, could be a promising treatment for patients with multilevel cervical degenerative disc disease (DDD). An advantage of this technique is that it uses an optimal procedure according to the status of each level. However, information is lacking regarding the influence of the relative location of the replacement and the fusion segment in vivo.

Purpose

We conducted the present study to investigate whether the location of the fusion affected the behavior of the disc replacement and adjacent segments in HS in vivo.

Study Design

This is an observational study.

Patient Sample

The numbers of patients in the arthroplasty-fusion (AF) and fusion-arthroplasty (FA) groups were 51 and 24, respectively.

Outcome Measures

The Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), and Visual Analog Scale (VAS) scores were evaluated. Global and segmental lordosis, the range of motion (ROM) of C2–C7, and the operated and adjacent segments were measured. Fusion rate and radiological changes at adjacent levels were observed.

Methods

Between January 2010 and July 2016, 75 patients with cervical DDD at two contiguous levels undergoing a two-level HS were retrospectively reviewed. The patients were divided into AF and FA groups according to the locations of the disc replacement. Clinical outcomes were evaluated according to the JOA, NDI, and VAS scores. Radiological parameters, including global and segmental lordosis, the ROM of C2–C7, the operated and adjacent segments, and complications, were also evaluated.

Results

Although the JOA, NDI, and VAS scores were improved in both the AF and the FA groups, no significant differences were found between the two groups at any follow-up point. Both groups maintained cervical lordosis, but no difference was found between the groups. Segmental lordosis at the fusion segment was significantly improved postoperatively (p<.001), whereas it was maintained at the arthroplasty segment. The ROM of C2–C7 was significantly decreased in both groups postoperatively (AF p=.001, FA p=.014), but no difference was found between the groups. The FA group exhibited a non-significant improvement in ROM at the arthroplasty segment. The ROM adjacent to the arthroplasty segment was increased, although not significantly, whereas the ROM adjacent to the fusion segment was significantly improved after surgery in both groups (p<.001). Fusion was achieved in all patients. No significant difference in complications was found between the groups.

Conclusions

In HS, cephalic or caudal fusion segments to the arthroplasty segment did not affect the clinical outcomes and the behavior of CDA. However, the ROM of adjacent segments was affected by the location of the fusion segment; segments adjacent to fusion segments had greater ROMs than segments adjacent to arthroplasty segments.  相似文献   

10.
Objective To explore the characteristics of diffusion tensor imaging (DTI)magnetic resonance(MR) imaging in healthy native kidneys. Methods Eighty patients without chronic kidney disease underwent DTI-MRI with spin echo-echo planar (SE-EPI) sequences and array spatial sensitivity encoding technique (ASSET). Cortical and medullary mean diffusivity (MD), axial and radial diffusivity(AD and RD) values and primary, secondary and tertiary eigenvalues (λ1, λ2, λ3) and fractional anisotropy (FA) were analyzed in both kidneys and in different genders. Physiological indexes including age, gender, height, weight, body mass index (BMI), body surface area (BSA), and estimated glomerular filtration rate (eGFR) were recorded. Correlations between DTI parameters and physiological indexes were analyzed. Results Cortical MD, λ2, λ3, RD values were higher than corresponding medullary values except for λ1 value. Cortical FA value was lower than medullary FA value. Cortical FA, λ1 values and medullary FA were higher in left kidney thanin right kidney. Medullary λ3 and RD valueswere lower in left kidney than in right kidney. Medullary λ2, λ3 and RD valueswere higher and medullary FA values were lower in female than in male. Medullary FA (r=0.351, P=0.002) and λ1 (r=0.277, P=0.018) positively correlated with eGFR and medullary FA (r=-0.250, P=0.033) negatively correlated with age. Conclusions Renal water molecular diffusion differences exist in human bilateral kidneys and different genders. Renal medullary tubular regularity, tubular diffusion and perfusion correlate with age.  相似文献   

11.

This study aimed to systematically review the literature to determine the clinical utility and perspectives of diffusion tensor imaging (DTI) in the management of patients with brainstem cavernous malformations (BSCMs). PubMed, Embase, and Cochrane were searched for English-language articles published until May 10, 2021. Clinical studies and case series describing DTI-based evaluation of patients with BSCMs were included. Fourteen articles were included. Preoperative DTI enabled to adjust the surgical approach and choose a brainstem safe entry zone in deep-seated BSCMs. Preoperatively lower fractional anisotropy (FA) of the corticospinal tract (CST) correlated with the severity of CST injury and motor deficits. Postoperatively increased FA and decreased apparent diffusion coefficient (ADC) corresponded with the normalization of the perilesional CST, indicating motor improvement. The positive (PPV) and negative predictive value (NPV) of qualitative DTI ranged from 20 to 75% and from 66.6 to 100%, respectively. The presence of preoperative and postoperative motor deficits was associated with a higher preoperative resting motor threshold (RMT) and lower FA. A higher preoperative CST score was indicative of a lower preoperative and follow-up Medical Research Council (MRC) grade. DTI facilitated the determination of a surgical trajectory with minimized risk of WMTs’ damage. Preoperative FA and RMT might indicate the severity of preoperative and postoperative motor deficits. Preoperative CST score can reliably reflect patients’ preoperative and follow-up motor status. Due to high NPV, normal CST morphology might predict intact neurological outcomes. Contrarily, sparse and relatively low PPV limits the reliable prediction of neurological deficits.

  相似文献   

12.
This study was designed to investigate differences of white matter (WM) involvement patterns in various motor neuron disorders (MND) by use of diffusion tensor imaging (DTI).DTI was acquired in ALS (n =?20), primary lateral sclerosis (n =?20), pure hereditary spastic paraparesis (HSP) (n =?20), and complicated HSP (n =?12). The data analysis was performed by voxelwise comparison of fractional anisotropy (FA) maps at group level together with fibre tracking in regions of interest (ROI) accompanied by tractwise fractional anisotropy statistics. DTI analysis revealed widespread patterns of alterations with a predominant deterioration of the motor system. These alterations encompassed, as the key structures, not only the corticospinal tracts (CST) but also distinct areas of the corpus callosum (CC), in particular its motor segment III. In conclusion, whole brain-based and tract-based DTI analysis was able to define a distinct WM pathoanatomy of different MND. These results may serve as an additional guidance in the identification of MRI-based parameters by showing a consistent CST and CC involvement, with differences in the extent of pathology, across a range of clinically different disorders. For potential future developments in MRI diagnostics in MND, a (perhaps multiparametric) ROI-based approach should include CST and the CC motor segment.  相似文献   

13.
White matter (WM) tract damage was assessed in patients with the behavioral variant frontotemporal dementia (bvFTD) and the 3 primary progressive aphasia (PPA) variants and compared with the corresponding brain atrophy patterns. Thirteen bvFTD and 20 PPA patients were studied. Tract-based spatial statistics and voxel-based morphometry were used. Patients with bvFTD showed widespread diffusion tensor magnetic resonance imaging (DT MRI) abnormalities affecting most of the WM bilaterally. In PPA patients, WM damage was more focal and varied across the 3 syndromes: left frontotemporoparietal in nonfluent, left frontotemporal in semantic, and left frontoparietal in logopenic patients. In each syndrome, DT MRI changes extended beyond the topography of gray matter loss. Left uncinate damage was the best predictor of frontotemporal lobar degeneration diagnosis versus controls. DT MRI measures of the anterior corpus callosum and left superior longitudinal fasciculus differentiated bvFTD from nonfluent cases. The best predictors of semantic PPA compared with both bvFTD and nonfluent cases were diffusivity abnormalities of the left uncinate and inferior longitudinal fasciculus. This study provides insights into the similarities and differences of WM damage in bvFTD and PPA variants. DT MRI metrics hold promise to serve as early markers of WM integrity loss that only at a later stage may be detectable by volumetric measures.  相似文献   

14.
Poor nutritional supply to the intervertebral disc is believed to be an important factor leading to disc degeneration. However, little is known regarding nutritional transport in human annulus fibrosus (AF) and its relation to tissue morphology. We hypothesized that solute diffusivity in human AF is anisotropic and inhomogeneous, and that transport behaviors are associated with tissue composition and structure. To test these hypotheses, we measured the direction‐dependent diffusivity of a fluorescent molecule (fluorescein, 332 Da) in three regions of AF using a fluorescence recovery after photobleaching (FRAP) technique, and associated transport results to the regional variation in water content and collagen architecture in the tissue. Diffusivity in AF was anisotropic, with higher values in the axial direction than in the radial direction for all regions investigated. The values of the diffusion coefficient ranged from 0.38 ± 0.25 × 10?6 cm2/s (radial diffusivity in outer AF) to 2.68 ± 0.84 × 10?6 cm2/s (axial diffusivity in inner AF). In both directions, diffusivity decreased moving from inner to outer AF. Tissue structure was investigated using both scanning electron microscopy and environmental scanning electron microscopy. A unique arrangement of microtubes was found in human AF. Furthermore, we also found that the density of these microtubes varied moving from inner to outer AF. A similar trend of regional variation was found for water content, with the highest value also measured in inner AF. Therefore, we concluded that a relationship exists among the anisotropic and inhomogeneous diffusion in human AF and the structure and composition of the tissue. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1625–1630, 2009  相似文献   

15.
目的 观察房颤时人心房肌细胞动作电位变化及迷走神经递质乙酰胆碱(ACh)对离体人心房肌动作电位(AP)及有效不应期(ERP)的影响.方法 选择20例心脏瓣膜病患者分为两组,其中11例合并房颤者为房额组(AF),9例窦性心律者为对照组(SR),术中取右心耳组织,采用玻璃微电极技术,检测两组患者静息膜电位(RMP),动作电位复极达90%的时程(APD90),动作电位复极达50%的时程(APD50)及不同起搏频率下APD90的变化,同时观察给予Ach前后上述指标的变化.结果 Ach灌注前,AF组与SR组间RMP( 63.70±3.00) mV比(54.70 ±2.19) mV、APD90 (312.60±11.92) ms比(406.30±14.61) ms、APD50( 177.30±14.05) ms比(218.50±15.10) ms差异有统计学意义(P<0.05).Ach灌注后,AF与SR两组间RMP(67.8±2.0) mV比(61.4±1.8) mV、APD90 (263.60±13.38) ms比(316.20±15.40) ms、APD50( 173.60±16.82) ms 比(217.60±15.16) ms差异有统计学意义(P<0.05).与灌注前自身比较,两组RMP显著增高、APD90显著缩短(P<0.05).APD50差异无统计学意义(P>0.05).但在AF组患者,其APD90缩短程度( △APD90,%)较SR组小(P<0.05).结论 房颤时存在心房组织APD缩短,频率适应性降低等电重构,它促进了房颤的维持.Ach可加重重构作用,但在慢性房颤中这种作用减弱.这种改变可能是机体对抗房颤的一种调节机制.  相似文献   

16.
Hepatic artery thrombosis (HAT) is a major cause of patient morbidity and graft loss in pediatric liver transplantation (OLT). Although some grafts may be salvaged by arterial thrombectomy and reconstruction, many patients require retransplantation. Patient survival is reduced by HAT. It has been suggested that the incidence of HAT may be altered by the use of reduced-size grafts (RSG). We analyzed our series of infants receiving OLT to determine the frequency of HAT in full-size OLT, cadaveric RSG, and living-related RSG. The role of arterial anastomotic technique in the development of HAT was also examined. Between 10/1/84 and 12/7/90 433 liver transplants were performed. During this period 100 patients between 3 months and 2 years of age (mean 13 months) received 134 liver grafts. The mean weight at the time of transplant was 7.9 kg. (range: 1.9-15 kg). Of the 134 grafts, 60 were whole livers, 61 were cadaveric RSGs, and 13 were living-related RSGs. The cadaveric RSGs were 9 right lobe grafts, 21 left lobe grafts, and 31 left lateral segment grafts. Twenty-seven of the cadaveric RSGs were from split livers, while the other 34 were simple reductions. All 13 living-related RSGs were left lateral segments. HAT occurred in 15 of 60 (25%) whole livers, 9 of 61 (15%) cadaveric RSGs, and 3 of 13 (23%) of the living-related-donor RSGs (P = NS). Subdividing the cadaveric RSGs revealed that HAT occurred in 3 of 9 (33%) right lobe grafts, 3 of 21 (14%) left lobe grafts, and 3 of 31 (10%) left lateral segment grafts (P = NS). The site of the arterial anastomosis in the recipient correlated with the incidence of HAT (hepatic artery 21/86 [24%], celiac axis 1/9 [11%], aorta 2/32 [6%], P = 0.06). In conclusion, it appears that use of a cadaveric left lobe or left lateral segment graft and an aortic arterial anastomosis reduces the risk of hepatic artery thrombosis in liver transplant recipients less than 2 years of age.  相似文献   

17.
The use of computational approaches in the analysis of high resolution magnetic resonance images (MRI) of the human brain provides a powerful tool for in vivo studies of brain anatomy. Here, we report results obtained with a voxel-wise statistical analysis of hemispheric asymmetries in regional 'amounts' of gray matter, based on MRI scans obtained in 142 healthy young adults. Firstly, the voxel-wise analysis detected the well-known frontal (right > left) and occipital (left > right) petalias. Secondly, our analysis confirmed the presence of left-greater-than-right asymmetries in several posterior language areas, including the planum temporale and the angular gyrus; no significant asymmetry was detected in the anterior language regions. We also found previously described asymmetries in the cingulate sulcus (right > left) and the caudate nucleus (right > left). Finally, in some brain regions we observed highly significant asymmetries that were not reported before, such as in the anterior insular cortex (right > left). The above asymmetries were observed in men and women. Our results thus provide confirmation of the known structural asymmetries in the human brain as well as new findings that may stimulate further research of hemispheric specialization.  相似文献   

18.
目的 利用扩散张量成像(DTI)和纤维跟踪技术显示胼胝体发育不良状态下脑内纤维结构的变化。方法患者,男,9岁,头痛1周。采用SIEMENS Trio2003T完成全脑MRI和DTI数据收集和后处理。结果常规MRI显示胼胝体体中部以后缺如,半球间蛛网膜囊肿,右侧向上延伸。纤维跟踪技术显示左侧弓状纤维柬、下纵行纤维柬、扣带柬、海马及外囊等主要的连合、联合纤维走行方向与正常发育不同,有左右侧相互支援的趋势。结论DTI纤维跟踪技术能精确、直观显示先天性发育畸形的脑内白质纤维柬,有助于预后的评估。  相似文献   

19.
This study investigated correlations between American Spinal Injury Association (ASIA) clinical injury motor scores in patients with traumatic cervical cord injury and magnetic resonance (MR) diffusion tensor imaging (DTI) parameters. Conventional imaging and DTI were performed to evaluate 25 patients (age, 39.7±13.9 years; 4 women, 21 men) with blunt spinal cord injury and 11 volunteers (age, 31.5±10.7 years; 3 women, 8 men). Cord contusions were hemorrhagic (HC) in 13 and non-hemorrhagic (NHC) in 12 patients. The spinal cord was divided into three regions to account for spatial and pathological variation in DTI parameters. Comparisons of regional and injury site mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity ( λ(⊥)), and longitudinal diffusivity ( λ(‖)) were made with control subjects. ASIA motor scores were correlated with DTI using linear regression analysis. HC and NHC patients showed significant reduction (p<0.001) in MD and λ(‖) in all three regions. At the injury site, significant decreases in FA and λ(‖) were seen for both injury groups (p<0.001). λ(⊥) values were significantly increased only for patients with NHC (p<0.05). Significant reduction in FA and λ(‖) (p<0.0001) was observed at the whole cord level between the injured (NH and NHC) and control groups. Within the NHC group, strong correlations were observed between ASIA motor scores and average MD, FA, λ(⊥), and λ(‖) at the injury site. However, no correlation was observed within the HC group between any of the DTI parameters and ASIA motor scores. DTI parameters reflect the severity of spinal cord injury and correlate well with ASIA motor scores in patients with NHC.  相似文献   

20.
Abstract

Objectives. Catestatin (CST) is a new endogenous neuropeptide with a potent catecholamine release-inhibitory activity. This study was to investigate plasma CST levels in patients with coronary heart disease (CHD) and to determine the clinical significance of plasma CST in cardiovascular events. Methods. A total of 120 CHD patients and 30 age/sex-matched healthy subjects were enrolled. Plasma CST level was measured using enzyme-linked immunosorbent assay (ELISA) and norepinephrine (NE) level was measured using high-performance liquid chromatography (HPLC). Clinical and laboratory data during hospitalization were collected, and a follow-up of 1045 days was carried out. Results. Compared with controls, CHD patients had significantly higher plasma CST and NE levels on admission. ST segment elevation myocardial infarction (STEMI) patients had higher CST levels than angina pectoris patients had, but CST/NE ratios were unchanged among controls and different CHD subgroups. Plasma NE was the only independent factor associated with CST. As a dichotomous variable divided by the median value, plasma CST on admission was not associated with adverse cardiovascular events. Conclusions. Plasma CST level was positively correlated with that of NE and was elevated in parallel with that of NE in the different myocardial ischemia states. Plasma CST on admission was neither associated with adverse cardiac events nor was there any significant relationship between plasma CST and onset of new cardiovascular events. The pathophysiological role of CST in CHD needs further studies.  相似文献   

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