Evaluation of white matter myelination in preterm infants using DTI and MRI / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the features of white matter myelin development in preterm infants using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI).</p><p><b>METHODS</b>A total of 31 preterm infants with a gestational age of ≤32 weeks and a birth weight of <1 500 g were enrolled. According to head MRI findings, these infants were divided into preterm group with brain injury (12 infants) and preterm group without brain injury (19 infants). A total of 24 full-term infants were enrolled as control group. Head MRI and DTI were performed at a gestational age or corrected gestational age of 37-40 weeks. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured for the same regions of interest in the three groups.</p><p><b>RESULTS</b>The preterm group with brain injury showed a significantly lower FA value of the posterior limb of the internal capsule than the preterm group without brain injury and full-term control group (P<0.05). The preterm groups with and without brain injury showed significantly lower FA values of frontal white matter and lenticular nucleus than the full-term control group (P<0.05). The FA value of occipital white matter showed no significant differences among the three groups (P>0.05). Compared with the full-term control group, the preterm groups with and without brain injury showed significantly higher ADC values of the posterior limb of the internal capsule, lenticular nucleus, occipital white matter, and frontal white matter (P<0.05).</p><p><b>CONCLUSIONS</b>After brain injury, preterm infants tend to develop disorder or delay of white matter myelination in the posterior limb of the internal capsule. At a corrected full-term gestational age, the preterm infants with and without brain injury have a lower grade of maturity in periventricular white matter and grey matter than full-term infants.</p>

Proton magnetic resonance spectroscopy and diffusion tensor imaging study of first-episode patients with positive symptoms of schizophrenia / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the changes in the frontal white matter, the head of the hippocampus, and the anterior cingulate fasciculus metabolites in first-episode patients with positive symptoms of schizophrenia.</p><p><b>METHODS</b>Twenty first-episode patients with positive symptoms of schizophrenia underwent diffusion tensor imaging (DTI) and proton multi-voxel spectroscopy (1H-MRS) examination. 1H-MRS images were obtained from two sides of the frontal white matter, the head of the hippocampus and the anterior cingulate fasciculus regions. The metabolites detected included N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine and phosphocreatine (Cr), and the ratios of NAA/Cr, Cho/Cr and NAA/Cho were determined. The fractional anisotropy (FA) values were measured in the frontal white matter, the head of the hippocampus, and the anterior cingulate fasciculus.</p><p><b>RESULTS</b>The Cho/Cr ratio was significantly reduced in the left frontal white matter (1.18 ± 0.21) of the patients as compared to the right side (1.44 ± 0.34, P<0.05). In the left head of the hippocampus, NAA/Cr (1.34 ± 0.45) and Cho/Cr (1.41 ± 0.39) were significantly reduced compared to those of the right side (1.75 ± 0.15 and 1.76 ± 0.36, respectively, P<0.05). No significant differences in the metabolite levels were found between the left and right anterior cingulate fasciculus (P>0.05). DTI showed similar FA values between the left and right sides of the frontal white matter, the head of the hippocampus, and the anterior cingulate fasciculus (P>0.05).</p><p><b>CONCLUSIONS</b>Patients with positive symptoms of schizophrenia have diminished neuronal integrity and/or function in the left frontal white matter and head of the hippocampus, but not in the anterior cingulate fasciculus.</p>

Brain regions for number involved in the processing of vocabulary of months in Chinese / 生理学报

The present study aimed to investigate the neuro-cognitive features in the processing of vocabularies of date in Chinese, using block-design functional magnetic resonance imaging (fMRI). Nineteen normal right-handed volunteers whose native language was Chinese performed judgments of vocabulary of month (JVM), the orientation of digit (JOD) and the meaning of words (JMW) respectively, while the fMRI data were recorded by Signa HDe 1.5T MR machine. All design of three tasks was adapted from previous studies with slight modification. The JOD and JWM were investigated as contrast conditions. JVM asked the subjects to determine whether the month belonged to the first half of the year. JOD was to tell whether the third digit had the same orientation (upright orientation or italic orientation) as the first two, and JMW was to determine whether the two-Chinese-character word was animate. The subjects responded according to the task instruction with a button pressing. Statistical parametric mapping (SPM2) was employed to process data and localize functional areas. We compared the average activation intensity of each activated brain regions in the same task against the rest and the activation intensity of the same regions in different tasks respectively. The activations in inferior parietal (BA40) and inferior occipital (BA18/19) were found in the JVM and JOD. The same areas in middle frontal (BA6), fusiform (BA18), posterior in right cerebellum areas were activated during the JVM and JMW. When the activation of the JMW was subtracted from the JVM, many areas concerning numerical processing, such as left anterior cingulate (BA32), post central (BA2), and the right superior temporal (BA39), superior parietal (BA7), as well as the inferior parietal (BA40), precuneus (BA7/19) of the bilateral hemispheres, were significantly activated. When the activation of the JOD was subtracted from the JVM, the left inferior occipital and the fusiform (BA18) of the bilateral hemispheres, which were also involved in the linguistic processing according to previous studies, were significantly activated. The above results prove that the processing of vocabulary of months in Chinese involves not only linguistic processing but also numerical processing; and these results further indicate that Chinese people might gain access to the cognitive experience of number during the process of acquisition of native language.

A sequence investigation on Wallerian degeneration after pontine infarction with diffusion tensor imaging / 中华神经科杂志

Objective To investigate the Wallerian degeneration of neural fiber tract in medulla and bilateral middle cerebellar peduncle following pontine infarction and to explore its impacts on neurological recovery.Methods Fourteen patients with a recent unilateral pontine infarct underwent the diffusion tensor imaging(DTI)and evaluations with the NIH stroke scale(NIHSS),the Fugl-Meyer motor scale(FM), ataxia rating scale(ARS)and the Barthel index(BI)at the first week(W1),the fourth(W4)and twelfth week(W12)respectively.Mean diffusivity(MD)and fractional anisotropy(FA)were measured at pons, medulla and middle cerebellar peduncle.Fourteenth age and gender matched volunteers underwent a DTI were studied as controls.Results Compared with the matched regions in controls,the FA values of infarct side medulla and bilateral middle cerebellar peduncle in patients significantly decreased at W1,W4 and W12(on the infarct side of medulla:W1:0.43?0.01;W4:0.37?0.02;W12:0.30?0.02;on the infarct side of middle cerebellar peduncle:W1:0.50?0.01;W4:0.43?0.02;W12:0.35?0.04;on the opposite side of middle cerebellar peduncle infarction:W1:0.54?0.02;W4:0.52?0.03;W12:0.47?0.04,t values are 1.92 to 28.56,P0.05 respectively).The absolute value of percent reduction of FA in infarct side medulla and bilateral middle cerebellar peduncle was correlated negatively to the absolute value of percent change of NIHSS and BI score(P