الملخص
Objective To explore the significance of signal classification by multimodal magnetic resonance imaging(MRI)(including conventional MRI,diffusion imaging,and susceptibility-weighted imaging)on neonatal punctate white matter lesions(PWML).Methods Between March 2011 and February 2013,neonates with PWML who underwent 3.0T MRI examination were recruited.The routine protocols included T1 weighted imaging (T1WI),T2 weighted imaging(T2WI),diffusion tensor imaging(DTI),and 3D-enhanced susceptibility-weighted angiography(ESWAN).Apparent diffusion coefficient(ADC)map,magnitude image,and phase image were obtained from DTI and ESWAN,respectively.The signal of PWML was one-to-one observed on T1WI,T2WI, ADC map and magnitude image.The combined signals were classified and the number of cases of each type was counted.Results Totally 84 neonates with PWML were included(preterm/term,47/37).Seven signal types were found and classified into three groups: ① Type Ⅰ was the most,59 cases,accounting for 70.24%,with the performance of high-signal intensity on T1WI,low-signal intensity on T2WI,low-signal intensity on ADC map,and high-signal intensity on magnitude image. ② Type Ⅱ,7 cases,accounting for 8.33%,high-signal intensity on T1WI,low-signal intensity on T2WI,low-signal intensity on ADC map,and low-signal intensity on magnitude image.③ Type Ⅲ - Ⅶ,26 cases,accounting for 30.95%,high-signal intensity on T1WI,low/iso-signal intensity on T2WI,low/iso-signal intensity on ADC map,high/iso-signal intensity on magnitude image.There was no significant difference in the incidence of different signal types between preterm and full-term PWML neonates. Conclusion Magnetic resonance signal may reflect the characteristics of PWML lesions.Signal classification of PWML by multimodal magnetic resonance imaging is helpful in determining injury type and has certain significance in guiding clinical treatment.
الملخص
Objective To compare metabolite ratios in the basal ganglia regions between preterm and term neonates and analyze the correlation between metabolite ratio and postmenstrual age(PMA)using 2D magnetic resonance spectroscopy(MRS)at 3.0T,so as to explore the value of MRS in evaluating neonatal brain development.Methods Normal neonates who underwent 3.0T MRS exam ination were recruited.Axial 2D MRS was performed with the point-resolved spectroscopy sequence(PRESS)(echo time/repetition time,144 ms/1 000 ms) through the basal ganglia covering three regions of interest(ROI)(i.e.bilateral lenticular nucleus,thalamus and white matter beside the anterior horn of lateral ventricle).The peak areas ratios of Cho/Cr,NAA/Cho and NAA/Cr were calculated.Metabolite ratios were compared between preterm and term neonates,and between three ROIs. Correlation between metabolite ratio and PMA was further analyzed.Results Totally 54 neonates were included(preterm/term,27/27).In all the three ROIs,preterm neonates presented significantly higher Cho/Cr(P<0.05) and significantly lower NAA/Cho ratios(P<0.001)than those of term neonates;higher NAA/Cr ratio was only observed in the lenticular nucleus of preterm neonates(P<0.001).Significant differences in metabolite ratios were detected among the three ROIs in preterm group(P<0.05).For term group,metabolite ratios differed between lenticular nucleus and white matter beside the anterior horn of the lateral ventricle(P<0.01),while no difference between lenticular nucleus and thalamus was found(P>0.05).Significant correlation between metabolite ratio and PMA was found in all the three ROIs except NAA/Cr ratio in the white matter beside the anterior horn of the lateral ventricle.To be specific,we found linear negative correlation of Cho/Cr ratio(r= -0.325,-0.633,-0.438) and positive correlation of NAA/Cho ratio(r = 0.604,0.773,0.483)in all the three ROIs,but negative correlations of NAA/Cr ratio(r=0.487,0.367)in lenticular nucleus and thalamus with PMA.Conclusion Our findings suggest the tempo-spatial pattern of neonatal brain metabolite development in terms of anatomic location and PMA.Besides,the multi-voxel MRS presents potentials in establishing the normal topologic and age-matched reference in neonates and thus making brain maturation assessment and detection of early abnormal metabolism.
الملخص
<p><b>BACKGROUND</b>Mild hypoxic-ischemic encephalopathy (HIE) injury is becoming the major type in neonatal brain diseases. The aim of this study was to assess brain maturation in mild HIE neonatal brains using total maturation score (TMS) based on conventional magnetic resonance imaging (MRI).</p><p><b>METHODS</b>Totally, 45 neonates with clinically mild HIE and 45 matched control neonates were enrolled. Gestated age, birth weight, age after birth and postmenstrual age at magnetic resonance (MR) scan were homogenous in the two groups. According to MR findings, mild HIE neonates were divided into three subgroups: Pattern I, neonates with normal MR appearance; Pattern II, preterm neonates with abnormal MR appearance; Pattern III, full-term neonates with abnormal MR appearance. TMS and its parameters, progressive myelination (M), cortical infolding (C), involution of germinal matrix tissue (G), and glial cell migration bands (B), were employed to assess brain maturation and compare difference between HIE and control groups.</p><p><b>RESULTS</b>The mean of TMS was significantly lower in mild HIE group than it in the control group (mean ± standard deviation [SD] 11.62 ± 1.53 vs. 12.36 ± 1.26, P < 0.001). In four parameters of TMS scores, the M and C scores were significantly lower in mild HIE group. Of the three patterns of mild HIE, Pattern I (10 cases) showed no significant difference of TMS compared with control neonates, while Pattern II (22 cases), III (13 cases) all had significantly decreased TMS than control neonates (mean ± SD 10.56 ± 0.93 vs. 11.48 ± 0.55, P < 0.05; 12.59 ± 1.28 vs. 13.25 ± 1.29, P < 0.05). It was M, C, and GM scores that significantly decreased in Pattern II, while for Pattern III, only C score significantly decreased.</p><p><b>CONCLUSIONS</b>The TMS system, based on conventional MRI, is an effective method to detect delayed brain maturation in clinically mild HIE. The conventional MRI can reveal the different retardations in subtle structures and development processes among the different patterns of mild HIE.</p>
الموضوعات
Female , Humans , Infant, Newborn , Male , Brain , Pathology , Hypoxia-Ischemia, Brain , Diagnosis , Magnetic Resonance Imaging , Methodsالملخص
OBJECTIVE@#To detect the activation pattern of the thalamus in human by the functional magnetic resonance imaging (fMRI) with the electrical stimulation of different intensities, and to explore the mechanism of this area in pain modulation.@*METHODS@#Ten healthy right-handed volunteers were given different electrical stimulations of 1-, 2-, and 3- times pain threshold respectively. The whole-brain was scanned simultaneously by GE 1.5T magnetic resonance imaging system. The data were postprocessed by analysis of functional neuroimages (AFNI) to establish the regional activity maps of the thalamus.@*RESULTS@#Patterns of functional activity showed a positive linear relationship between the activation signals and stimulation intensity in bilateral thalamus, whereas the BOLD signal of bilateral medial thalamus demonstrated that the curve was similar to the exponential function. Meanwhile, the activation in the contralateral lateral thalamus (cThl), but not the contralateral medial thalamus (cThm), was prominent compared with the corresponding ipsilateral subregions, and only the lateral thalamus displayed a contralateral biased representation while the medial thalamus lacked this property.@*CONCLUSION@#Thalamus is one of the vital components in the pain modulation network, which can present spatial segregation activations with unique characteristics of stimulation intensity-response in each subregion. All the results are helpful to understand the crucial role of thalamus in processing the pain information.