Multivoxel Proton Magnetic Resonance Spectroscopy Research Articles

Neurochemical differences in core regions of the autistic brain: a multivoxel 1H-MRS study in children

Autism spectrum disorder (ASD) is a neurodevelopmental condition which compromises various cognitive and behavioural domains. The understanding of the pathophysiology and molecular neurobiology of ASD is still an open critical research question. Here, we aimed to address ASD neurochemistry in the same time point at key regions that have been associated with its pathophysiology: the insula, hippocampus, putamen and thalamus. We conducted a multivoxel proton magnetic resonance spectroscopy (1H-MRS) study to non-invasively estimate the concentrations of total choline (GPC + PCh, tCho), total N-acetyl-aspartate (NAA + NAAG, tNAA) and Glx (Glu + Gln), presenting the results as ratios to total creatine while investigating replication for ratios to total choline as a secondary analysis. Twenty-two male children aged between 10 and 18 years diagnosed with ASD (none with intellectual disability, in spite of the expected lower IQ) and 22 age- and gender-matched typically developing (TD) controls were included. Aspartate ratios were significantly lower in the insula (tNAA/tCr: p = 0.010; tNAA/tCho: p = 0.012) and putamen (tNAA/tCr: p = 0.015) of ASD individuals in comparison with TD controls. The Glx ratios were significantly higher in the hippocampus of the ASD group (Glx/tCr: p = 0.027; Glx/tCho: p = 0.011). Differences in tNAA and Glx indices suggest that these metabolites might be neurochemical markers of region-specific atypical metabolism in ASD children, with a potential contribution for future advances in clinical monitoring and treatment.

Triangulating brain alterations in anorexia nervosa: a multimodal investigation of magnetic resonance spectroscopy, morphometry and blood-based biomarkers

The acute state of anorexia nervosa (AN) is associated with widespread reductions in cortical gray matter (GM) thickness and white matter (WM) volume, suspected changes in myelin content and elevated levels of the neuronal damage marker neurofilament light (NF-L), but the underlying mechanisms remain largely unclear. To gain a deeper understanding of brain changes in AN, we applied a multimodal approach combining advanced neuroimaging methods with analysis of blood-derived biomarkers. In addition to standard measures of cortical GM thickness and WM volume, we analyzed tissue-specific profiles of brain metabolites using multivoxel proton magnetic resonance spectroscopy, T1 relaxation time as a proxy of myelin content leveraging advanced quantitative MRI methods and serum NF-L concentrations in a sample of 30 female, predominately adolescent patients with AN and 30 age-matched female healthy control participants. In patients with AN, we found a reduction in GM cortical thickness and GM total N-acetyl aspartate. The latter predicted higher NF-L levels, which were elevated in AN. Furthermore, GM total choline was elevated. In WM, there were no group differences in either imaging markers, choline levels or N-acetyl aspartate levels. The current study provides evidence for neuronal damage processes as well as for increased membrane lipid catabolism and turnover in GM in acute AN but no evidence for WM pathology. Our results illustrate the potential of multimodal research including tissue-specific proton magnetic resonance spectroscopy analyses to shed light on brain changes in psychiatric and neurological conditions, which may ultimately lead to better treatments.

Studying of changes in metabolites in the brain in patients with COVID-19 according to multivoxel 1H-MRS: prospective study

INTRODUCTION: Members of the coronavirus family can affect the human central nervous system, causing various neurological complications in patients with SARS-CoV-2. Proton magnetic resonance spectroscopy (1H-MRS) seems to be a promising technique for assessing the prognosis of persistent neurological manifestations and complications, determining the completeness of a patient’s recovery during long-term follow-up. OBJECTIVE: To study changes in the metabolites profile in the brain with relation to cognitive impairment in patients with COVID-19.MATERIALS AND METHODS: 68 patients with verified COVID-19 and neurological complaints underwent a diagnostic workup, including a psychoneurological assessment and MRI of the brain with multivoxel proton magnetic resonance spectroscopy (1H-MRS), starting in the first 2 weeks from the onset of the disease. In 11 patients, a complex examination was repeated 7–8 months after the onset of the disease. The exclusion criteria were acute severe neurological symptoms, age over 65 years, artificial lung ventilation, lung CT score III–IV, as well as information about pre-Covid neuropsychiatric disorders. As a control group, earlier collected data of 10 healthy volunteers (age 30–67 years) were taken from a local database. Statistics: Intergroup differences in the ratios of metabolites peak areas determined by the 1H-MPC method were assessed using the nonparametric Mann-Whitney test with Bonferroni’s correction for multiple comparisons. Values were considered statistically significant at p<0.05. RESULTS: According to 1H-MRS, all patients with COVID-19 showed metabolic changes in the brain: a statistically significant increase in mI/Cr in the white and gray matter and a diffuse decrease in the levels of Cho/Cr in the supraventricular white matter, even in the absence of any changes in structural MRI. DISCUSSOIN: Patients were divided into three subgroups according to the severity of neurological symptoms that arose with the onset of the coronavirus infection. The most pronounced metabolic changes were found in the group with severe neurological manifestations (NM). At follow-up, a gradual recovery of the metabolite profile was noted, but in our sample group complete normalization was not achieved within the specified time frame. CONCLUSION: The obtained data indicate metabolic changes associated with SARS-CoV-2 infection, as well as the prospects for using the 1H-MPC technique in the diagnosis of neurological complications of the new coronavirus infection, including manifestations of a psychoneurological syndrome associated with COVID-19.><0.05.RESULTS: According to 1H-MRS, all patients with COVID-19 showed metabolic changes in the brain: a statistically significant increase in mI/Cr in the white and gray matter and a diffuse decrease in the levels of Cho/Cr in the supraventricular white matter, even in the absence of any changes in structural MRI.DISCUSSOIN: Patients were divided into three subgroups according to the severity of neurological symptoms that arose with the onset of the coronavirus infection. The most pronounced metabolic changes were found in the group with severe neurological manifestations (NM). At follow-up, a gradual recovery of the metabolite profile was noted, but in our sample group complete normalization was not achieved within the specified time frame.CONCLUSION: The obtained data indicate metabolic changes associated with SARS-CoV-2 infection, as well as the prospects for using the 1H-MPC technique in the diagnosis of neurological complications of the new coronavirus infection, including manifestations of a psychoneurological syndrome associated with COVID-19.

Proton magnetic resonance spectroscopy in children with delayed mental and speech development associated with focal temporal lobe epilepsy

Background. The delays in mental and speech development are caused by epilepsy, and a special place among the forms of which is focal temporal epilepsy. The study of biomarkers of the considered pathological condition using proton magnetic resonance spectroscopy as indicators amenable to objective assessment and measurement determines the practical relevance of this work.
 Aim. The aim of the study was to determine the role and place of proton magnetic resonance spectroscopy in clinical practice in children with mental and speech retardation associated with temporal lobe epilepsy.
 Materials and methods. 37 children aged 2 to 10 years were studied. Of these, 15 children with a diagnosis of mental and speech development delay, structural focal temporal epilepsy were included in the first comparison group. The second comparison group consisted of 12 children without CNS pathology undergoing 1H-MRI examination to exclude somatic diseases. The third comparison group consisted of 10 children with structural focal temporal epilepsy, without mental and speech development delay.
 Discussion. Multivoxel proton magnetic resonance spectroscopy (method PRESS) was used to determine the concentration of neurometabolites in the brain tissues of patients. In patients with mental and speech development delay associated with temporal epilepsy, a decrease in the ratio of NAA/Cr concentrations (p 0.05) was revealed in the postcentral gyrus on the right, temporal lobe on the right and hippocampus and inner capsule on both sides, due to a decrease in the concentration of N-acetylaspartate; an increase in the ratio of Cho/Cr concentrations (p 0.05) in the prefrontal cortex, postcentral gyrus and inner capsule on both sides, due to an increase in the concentration of choline. Two patients also showed lipid peaks on the lesion side when compared with EEG data.
 Conclusions. The revealed metabolic changes in patients with delayed mental and speech development associated with temporal lobe epilepsy may be useful as an additional method of differential diagnosis with other forms of mental and speech development delay.

Hypertensive disorders of pregnancy and alterations in brain metabolites in preterm infants: A multi-voxel proton MR spectroscopy study

BackgroundInfants born to mothers with hypertensive disorders of pregnancy (HDP) have adverse neurodevelopmental consequences in later life. Magnetic resonance spectroscopy (MRS) is used to predict subsequent neurodevelopment in the field of perinatology. AimWe aimed to determine whether exposure to HDP in utero leads to alterations in brain metabolites in preterm infants using multi-voxel proton MRS at term-equivalent age. Study designRetrospective cohort study. SubjectsA total of 103 preterm infants born before 34 weeks of gestation at Nagoya University Hospital between 2010 and 2018 were eligible. Twenty-seven infants were born to mothers with HDP (HDP group), and 76 were born to mothers without HDP (non-HDP group). Outcome measuresThe peak area ratios of N-acetylaspartate (NAA)/choline (Cho), NAA/creatine (Cr), and Cho/Cr were evaluated at 10 designated regions of interest (bilateral frontal lobes, basal ganglia, thalami, temporal lobes, and occipital lobes). ResultsThe peak area ratios of NAA/Cho and NAA/Cr in the bilateral thalami were significantly higher in the HDP group than in the non-HDP group after adjustment for covariates (postmenstrual age at MRS assessment and infant sex). No significant differences were observed in other regions. Preeclampsia, abnormal umbilical artery blood flow, and fetal growth restrictions were significantly associated with increased NAA/Cho and NAA/Cr ratios in the thalami. ConclusionsBased on the evidence that NAA/Cho and NAA/Cr ratios constantly increase with postmenstrual age in normal brain development, exposure to maternal HDP in utero may accelerate brain maturation and increase neuronal activity in preterm infants.

Brain neurometabolites differences in individuals with subjective cognitive decline plus: a quantitative single- and multi-voxel proton magnetic resonance spectroscopy study.

Subjective cognitive decline plus could be an extremely early phase of Alzheimer's disease; however, changes of N-acetylaspartate, myoinositol, and N-acetylaspartate/myoinositol is still unknown at this stage. This study aimed to explore brain neurometabolic alterations in patients with subjective cognitive decline plus using quantitative single-voxel and multi-voxel 1H-magnetic resonance spectroscopy. A total of 91 participants were enrolled and underwent a GE 3.0-T magnetic resonance imaging, including 33 elderly controls, 27 patients with subjective cognitive decline plus, and 31 patients with amnestic mild cognitive impairment (MCI). Single-voxel and multi-voxel 1H-magnetic resonance spectroscopy were used to investigate the differences in neurometabolite levels among the three groups. Compared with elderly controls, patients with subjective cognitive decline plus showed significant decline in N-acetylaspartate and N-acetylaspartate/myoinositol values in multiple regions, and amnestic MCI participants demonstrated more significant decreased N-acetylaspartate and N-acetylaspartate/myoinositol levels in multiple regions. The combined concentrations of N-acetylaspartate with myoinositol showed an excellent discrimination between those with subjective cognitive decline plus and elderly controls as compared to that obtained using N-acetylaspartate/myoinositol ratios with the area under the receiver operating characteristic curve of 0.895 and 0.860, respectively. Likewise, the combined area under the curve for differentiating patients with subjective cognitive decline plus from amnestic MCI was obtained using the combined levels of N-acetylaspartate with myoinositol was 0.892. This was also higher than the combined area under the curve of 0.836 obtained using N-acetylaspartate/myoinositol ratios. Moreover, N-acetylaspartate levels in the left hippocampus and left posterior cingulate cortex (PCC) was positively related to the Auditory Verbal Learning Test delayed recall scores in patients with subjective cognitive decline plus, whereas only the N-acetylaspartate/myoinositol ratio was positively related to this scale scores in the left hippocampus. Quantitative single-voxel and multi-voxel 1H-magnetic resonance spectroscopy can provide valuable information to detect alterative brain neurometabolites characteristics in patients with subjective cognitive decline plus. N-acetylaspartate concentrations may be used as one of the earliest neuroimaging markers at this stage, while N-acetylaspartate/myoinositol ratio could be more suitable for monitoring Alzheimer's disease progression.

Early Diagnosis of Neuropsychiatric Systemic Lupus Erythematosus by Deep Learning Enhanced Magnetic Resonance Spectroscopy

The neuropsychiatric systemic lupus erythematosus (NPSLE) has higher disability and mortality rates, which is one of the main causes of death in systemic lupus erythematosus (SLE) patients. Magnetic resonance spectroscopy (MRS) can detect the changes of metabolites in different intracranial areas in vivo in patients with SLE, so as to provide evidence for the early diagnosis of NPSLE. Different from the conventional single-voxel MRS, which can only screen one brain region with one metabolic change, we simultaneously detect 13 kinds of intracranial metabolic changes in nine brain regions by multivoxel proton MRS (MVS). We use a recursive feature elimination algorithm to select the most related metabolites for better identifying NPSLE. To accurately diagnosis NPSLE by these intracranial metabolites, we train a support vector machine deep stacked network (SVM-DSN) for quantitative analysis of these metabolites. Comparing with the conventional statistic method, which is about 70% of accuracy, the proposed model achieves 97.5% of accuracy for NPSLE diagnosis. We conclude the trained SVM-DSN can effectively analyze the metabolites obtained by multivoxel proton MRS for NPSLE diagnosis, which may help to early diagnosis and intervention of NPSLE, and alleviate the bias of manual screening.

Broad Learning Enhanced 1H-MRS for Early Diagnosis of Neuropsychiatric Systemic Lupus Erythematosus.

In this paper, we explore the potential of using the multivoxel proton magnetic resonance spectroscopy (1H-MRS) to diagnose neuropsychiatric systemic lupus erythematosus (NPSLE) with the assistance of a support vector machine broad learning system (BL-SVM). We retrospectively analysed 23 confirmed patients and 16 healthy controls, who underwent a 3.0 T magnetic resonance imaging (MRI) sequence with multivoxel 1H-MRS in our hospitals. One hundred and seventeen metabolic features were extracted from the multivoxel 1H-MRS image. Thirty-three metabolic features selected by the Mann-Whitney U test were considered to have a statistically significant difference (p < 0.05). However, the best accuracy achieved by conventional statistical methods using these 33 metabolic features was only 77%. We turned to develop a support vector machine broad learning system (BL-SVM) to quantitatively analyse the metabolic features from 1H-MRS. Although not all the individual features manifested statistics significantly, the BL-SVM could still learn to distinguish the NPSLE from the healthy controls. The area under the receiver operating characteristic curve (AUC), the sensitivity, and the specificity of our BL-SVM in predicting NPSLE were 95%, 95.8%, and 93%, respectively, by 3-fold cross-validation. We consequently conclude that the proposed system effectively and efficiently working on limited and noisy samples may brighten a noinvasive in vivo instrument for early diagnosis of NPSLE.

Magnetic Resonance Spectroscopy in Adolescent Cannabis Users: Metabolites in the Anterior Cingulate Cortex Reflects Individual Differences in Personality Traits and can Affect Rehabilitation Compliance.

The anterior cingulate cortex (ACC) has shown to play a role in impulsivity, fear, and anxiety. Considering, its high glutamate receptor density, it was chosen as a region of interest to investigate the role of glutamate transmission in drug dependance. We investigated the correlations between personality trait scores and glutamate-to-glutamine (Glx) ratio concentrations in the ACC in order to evaluate if (1) personality traits may increase the probability of drug use and (2) drug use can modify cerebral metabolic pattern contributing to addictive behaviors. Glx ratio concentrations in the ACC region were measured with high-resolution multivoxel proton magnetic resonance spectroscopy (1H-MRS). Personality traits were evaluated utilizing Cloninger's TCI-revised test. Bivariate correlations between personality scores of 28 teens cannabis users (males, mean age = 18.54 ± 2.80) were evaluated. In the ACC, we observed negative correlation between GG concentrations (r = -0.44, P = 0.05) and co-operativeness values (CO), choline (cho), and novelty seeking (NS) values (r = -0,45, P = 0.05). Low levels of glutamate and high levels of cho in the ACC were closely related to the CO and NS personality traits. Metabolic and personality patterns seems to be related to the risk of substance predisposition in adolescents. Our data contribute a possible support to the "top-down" control of the ACC on brain metabolism, due to the particular cerebral metabolic pattern found in "drug-using" adolescents.

Application Value of 3.0-T Multivoxel 1H-MR Spectroscopy in the Peritumoral Tissue of Brain Astrocytic Tumors.

This study aimed to explore metabolic features in the peritumoral tissue of different-rank brain astrocytic tumors using multivoxel proton magnetic resonance spectroscopy (1H-MRS) and to estimate its application value in the MRS quantitative ratio of brain astrocytic tumors. A total of 82 patients with brain astrocytic tumors, confirmed by postoperative pathological evaluation, were divided into low-grade astrocytic tumors [World Health Organization (WHO) grade I-II; 32 cases] and high-grade astrocytic tumors (WHO grade III-IV; 50 cases). The semi-quantitative and relative quantitative metabolite ratios of the parenchyma area, peritumoral tissue area, and normal area were measured. The P value was set as <0.05. The relative quantitative ratios of choline (Cho)/creatine (Cr) and Cho/N-acetyl aspartate (NAA) significantly differed in the peritumoral tissues of the high-grade astrocytic tumors and low-grade astrocytic tumors (P < 0.05), but NAA/Cr showed no significant difference. The changes in the metabolite ratio of the peritumoral tissue area in brain astrocytic tumors reflect the biological behavior of different tumors. They have a significant clinical value in classifying brain astrocytic tumors and indicating the scope of invasion.

Neurometabolic Remodeling in Chronic Hiv Infection: a Five-Year Follow-up Multi-Voxel Mrs Study

There is a lack of data about the long-term follow-up changes in neurometabolic profile and neuropsychological performance of HIV-positive subjects under continuous antiretroviral therapy (cART). The aim of the study was to assess changes in neurometabolic profile in chronically-infected, HIV-positive subjects during a five-year follow-up period, using multi-voxel proton magnetic resonance spectroscopy (1H-MRS). Nineteen neurologically asymptomatic, aviremic, HIV-positive subjects, underwent multi-voxel 2D MRS on a 3 T MR unit and synchronous neurocognitive assessment in a five-year follow-up period. Twelve voxels were placed in prefrontal cortices, anterior and posterior cingulate gyrus, intraparietal sulci, and frontal centrum semiovale white matter, to identify peaks of N-acetyl-aspartate (NAA), creatine (Cr), choline (Cho), and myoinositol (mI). Ratios of NAA/Cr, NAA/Cho, NAA/mI, mI/Cr, and Cho/Cr were analyzed. Longitudinal differences in ratios and neurocognitive scores were tested with the Wilcoxon signed-rank-test. Statistical significance was set at p ≤ 0.004 significant, and 0.05 > p > 0.004 trending toward significance. A significant longitudinal increase in NAA/Cr ratio was observed in 5/12 voxels, while there was a trend toward significance in an additional three. The increase in Cho/Cr reached statistical significance in one voxel. Changes in the mI/Cr ratio demonstrated a significant increase in 4/12 voxels. A progressive increase in NAA/Cr, followed by better neurocognitive performance, may be an indicator of brain plasticity in the setting of chronic HIV-related neuronal injury. A progressive mI/Cr increase could be partly explained by glial proliferation due to functional compartment remodeling and partly attributable to insufficient control of persistent neuroinflammation by cART.

Lack of choline elevation on proton magnetic resonance spectroscopy in grade I-III gliomas.

Elevated levels of choline are generally emphasized as marker of increased cellularity and cell membrane turnover in gliomas. In this study, we investigated the incidence rate of lack of choline/creatine and choline/water elevation in a population of grade I-III gliomas. A cohort of 41 patients with histopathologically confirmed gliomas underwent multi-voxel proton magnetic resonance spectroscopy on a 3 T magnetic resonance system prior to treatment. Peak areas for choline and myoinositol were measured from all voxels that exhibited hyperintensity on fluid-attenuated inversion recovery images and were normalized to creatine and unsuppressed water from each voxel. The average metabolite/creatine and metabolite/water ratios from these voxels were then computed. Similarly, average metabolite ratios were computed from normal brain parenchyma. Gliomas were considered for lack of choline elevation when choline/creatine and choline/water ratios from neoplastic regions were less than those from normal brain parenchyma regions. Six of 41 (14.6%) grade I-III gliomas showed lack of elevation for choline/creatine and choline/water ratios compared to normal brain parenchyma. Four of these six gliomas also demonstrated elevated levels of myoinositol/creatine ratio. All other gliomas (n = 35) had elevated choline levels from neoplastic regions relative to normal parenchyma. The sensitivity of choline/creatine or choline/water in determining a grade I-III glioma was 85.4%. These findings suggest that a lack of choline/creatine or choline/water elevation may be seen in some gliomas and low choline levels should not prevent us from considering the possibility of a grade I-III glioma.

Multivoxel 1H-MR Spectroscopy Biometrics for Preoprerative Differentiation Between Brain Tumors.

We investigated multivoxel proton magnetic resonance spectroscopy (1H-MRS) biometrics for preoperative differentiation and prognosis of patients with brain metastases (MET), low-grade glioma (LGG) and high-grade glioma (HGG). In total, 33 patients (HGG, 14; LGG, 9; and 10 MET) were included. 1H-MRS imaging (MRSI) data were assessed and neurochemical profiles for metabolites N-acetyl aspartate (NAA) + NAAG(NAA), Cr + PCr(total creatine, tCr), Glu + Gln(Glx), lactate (Lac), myo-inositol(Ins), GPC + PCho(total choline, tCho), and total lipids, and macromolecule (tMM) signals were estimated. Metabolites were reported as absolute concentrations or ratios to tCho or tCr levels. Voxels of interest in an MRSI matrix were labeled according to tissue. Logistic regression, receiver operating characteristic, and Kaplan–Meier survival analysis was performed. Across HGG, LGG, and MET, average Ins/tCho was shown to be prognostic for overall survival (OS): low values (≤1.29) in affected hemisphere predicting worse OS than high values (>1.29), (log rank < 0.007). Lip/tCho and Ins/tCho combined showed 100% sensitivity and specificity for both HGG/LGG (P < .001) and LGG/MET (P < .001) measured in nonenhancing/contrast-enhancing lesional tissue. Combining tCr/tCho in perilesional edema with tCho/tCr and NAA/tCho from ipsilateral normal- appearing tissue yielded 100% sensitivity and 81.8% specificity (P < .002) for HGG/MET. Best single biomarker: Ins/tCho for HGG/LGG and total lipid/tCho for LGG/MET showed 100% sensitivity and 75% and 100% specificity, respectively. HGG/MET; NAA/tCho showed 75% sensitivity and 84.6% specificity. Multivoxel 1H-MRSI provides prognostic information for OS for HGG/LGG/MET and a multibiometric approach for differentiation may equal or outperform single biometrics.

N-Acetylaspartate-to-creatine ratio in twelve brain locations among healthy men and women with different levels of education

Brain bioenergetics could be affected by many intrinsic and extrinsic factors, yet no link has been established between markers of bioenergetics in specific brain regions and educational level. In this cross-sectional study, we evaluated N-acetylaspartate-to-creatine ratio (NAA/Cr), a biomarker of brain functionality, using multivoxel proton magnetic resonance spectroscopy in twelve brain locations among healthy volunteers (n = 51; 30 females; age 47.8 ± 16.3 years) who earned either a high school diploma (36 out of 51) or a college degree (15 out of 51). Hierarchical multiple regression analysis revealed that our model as a whole (including level of education as a predictor variable, and age and gender as control variables) explained significant percentage of the variance in the NAA/Cr levels at 8 out of 12 specific brain locations (P< 0.05). This was highlighted in left anterior mesial cortex where the model explained 63.1% of the variance in brain NAA/Cr, with education and age make significant contributions (72.6% and 48.5%, respectively) to our model (P< 0.05). Having superior brain N-acetylaspartate-to-creatine ratio appears to be related with higher education in healthy men and women.

Preoperative brain temperature imaging on proton magnetic resonance spectroscopy predicts hemispheric ischemia during carotid endarterectomy for unilateral carotid stenosis with inadequate collateral blood flow

Objective Preoperative magnetic resonance (MR) angiography sometimes shows the absence of collateral flow via the circle of Willis. This study examined whether brain temperature (BT) imaging on multi-voxel proton MR spectroscopy after this finding increases the accuracy of predicting hemispheric ischemia during internal carotid artery (ICA) clamping during endarterectomy for patients with symptomatic unilateral carotid stenosis.Methods In 52 patients with ICA stenosis (≥70%) and absence of collateral blood flow via the circle of Willis on preoperative MR angiography, BT imaging was displayed using proton multi-voxel MR spectroscopy. The difference between BTs in the affected and contralateral hemispheres (BTaffected hemisphere − BTcontralateral hemisphere) in the deep white matter of the centrum semiovale was calculated and defined as hemispheric ΔBT. Development of cerebral hemispheric ischemia during ICA clamping was determined from intraoperative electroencephalography (EEG).Results Multivariate analysis revealed that high preoperative hemispheric ΔBT was significantly associated with development of EEG-defined hemispheric ischemia (95% confidence intervals [CIs], 5.376–15.452; p = 0.006). The positive-predictive value for development of EEG-defined hemispheric ischemia was significantly greater for preoperative hemispheric ΔBT following preoperative MR angiography (95%CI, 42–87%) than for preoperative MR angiography alone (95%CI, 13–37%).Conclusions For patients without collateral flow via the circle of Willis, BT imaging increases the predictive accuracy for development of hemispheric ischemia during ICA clamping during CEA.

Repeatability of two-dimensional chemical shift imaging multivoxel proton magnetic resonance spectroscopy for measuring human cerebral choline-containing compounds.

AIMTo investigate the repeatability of proton magnetic resonance spectroscopy in the in vivo measurement of human cerebral levels of choline-containing compounds (Cho).METHODSTwo consecutive scans were carried out in six healthy resting subjects at a magnetic field strength of 1.5 T. On each occasion, neurospectroscopy data were collected from 64 voxels using the same 2D chemical shift imaging (CSI) sequence. The data were analyzed in the same way, using the same software, to obtain the values for each voxel of the ratio of Cho to creatine. The Wilcoxon related-samples signed-rank test, coefficient of variation (CV), repeatability coefficient (RC), and intraclass correlation coefficient (ICC) were used to assess the repeatability.RESULTSThe CV ranged from 2.75% to 33.99%, while the minimum RC was 5.68%. There was excellent reproducibility, as judged by significant ICC values, in 26 voxels. Just three voxels showed significant differences according to the Wilcoxon related-samples signed-rank test.CONCLUSIONIt is therefore concluded that when CSI multivoxel proton neurospectroscopy is used to measure cerebral choline-containing compounds at 1.5 T, the reproducibility is highly acceptable.

Abstract TP49: Quantitative Evaluation of Proton Magnetic Resonance Spectroscopy on protection of Human Urinary Kallidinogenase in Neurons Against Ischemic Stroke

Introduction and Hypothesis: To evaluate the effect of Human Urinary Kallidinogenase (HUK) regarding the changes to brain metabolites in patients with acute ischemic cerebral infarction (AIS) by magnetic resonance spectroscopy. Methods: From 1, 2014 to 10, 2016, 57 patients with AIS who having MRI within 72 hours of onset of symptoms were randomly divided into an observation group and a control group. The control group was given standard care while the observation group was treated with HUK in additional to standard care. The levels of N-acetyl aspartate (NAA) and creatine (Cr) in the brain were measured by multi-voxel Proton magnetic resonance spectroscopy (MRS) before and one week after intervention The National Institutes of Health Stroke Scale (NIHSS) was performed using the Improved Rankin scale (mRA) score, Barthel index (BI) to evaluate clinical efficacy. The obtained data were assessed using percentages, t test, and F test in the SPSS 19.0 software. Results: The values of NAA, NAA/Cr, the NIHSS score, and the mRS were not significantly different between the two groups (P&gt; 0.05) at baseline before the treatment. One week post-observation, the values of both NAA and NAA/Cr in the central infarcted area were lower than before in both groups before the observation P &lt;0.05). The NAA and NAA/Cr in the peripheral infarcted areas of the observation group were higher than those in the control group , and the increase of NAA and NAA / Cr in the observation group was higher than that in the control group ( HUK group vs. Control group: NAA, NAA/Cr. P&lt;0.05: respectively). In addition, the NIHSS score, mRS score, and BI index were higher in the observation group than in the control group (P &lt;0.05). Conclusion: Treating patients with AIS with HUK can improve both the brain metabolic profile as well as patient’s clinical outcomes.

3D proton MR spectroscopy of the gray and white brain matter. A study of 15 volunteers

To assess the possibility of using multivoxel 3D proton MRS in healthy volunteers without organic brain pathology. In this study, 15 volunteers without organic brain pathology were examined using the 3D 1H-MRS. 3D proton MRS has proven to be an effective technique in studying the brain metabolism. One short-term series of examinations provided information on intact brain metabolism at different anatomical levels, which enabled their comparison both in spectral data and in parametric maps of the major metabolite distribution.

Apparent brain temperature imaging with multi-voxel proton magnetic resonance spectroscopy compared with cerebral blood flow and metabolism imaging on positron emission tomography in patients with unilateral chronic major cerebral artery steno-occlusive disease.

The purpose of the present study was to determine whether apparent brain temperature imaging using multi-voxel proton magnetic resonance (MR) spectroscopy correlates with cerebral blood flow (CBF) and metabolism imaging in the deep white matter of patients with unilateral chronic major cerebral artery steno-occlusive disease. Apparent brain temperature and CBF and metabolism imaging were measured using proton MR spectroscopy and 15O-positron emission tomography (PET), respectively, in 35 patients. A set of regions of interest (ROIs) of 5×5 voxels was placed on an MR image so that the voxel row at each edge was located in the deep white matter of the centrum semiovale in each cerebral hemisphere. PET images were co-registered with MR images with these ROIs and were re-sliced automatically using image analysis software. In 175 voxel pairs located in the deep white matter, the brain temperature difference (affected hemisphere-contralateral hemisphere: ΔBT) was correlated with cerebral blood volume (CBV) (r=0.570) and oxygen extraction fraction (OEF) ratios (affected hemisphere/contralateral hemisphere) (r=0.641). We excluded voxels that contained ischemic lesions or cerebrospinal fluid and calculated the mean values of voxel pairs in each patient. The mean ΔBT was correlated with the mean CBF (r=-0.376), mean CBV (r=0.702), and mean OEF ratio (r=0.774). Apparent brain temperature imaging using multi-voxel proton MR spectroscopy was correlated with CBF and metabolism imaging in the deep white matter of patients with unilateral major cerebral artery steno-occlusive disease.

Biochemical abnormalities in basal ganglia and executive dysfunction in acute- and euthymic-episode patients with bipolar disorder: A proton magnetic resonance spectroscopy study

BackgroundRecent studies found abnormal biochemical metabolism and executive cognitive deficits in acute bipolar disorder (BD). However, the evidence concerning in euthymic BD is limited. Thus, a comparison between acute and euthymic BD is conductive to better understanding the association between cognition and the outcome of neuroimaging. This study sought to investigate the relationship between the executive function and the biochemical metabolism in acute- and euthymic-episode BD patients and delineate the prominent endophenotype of BD. MethodsThree groups of participants were recruited in this study: 30 BD patients with an acute depressive episode, 22 euthymic BD patients, and 31 healthy controls. All participants were interviewed using the Structured Clinical Interview for DSM-IV, and underwent two-dimensional multivoxel proton magnetic resonance spectroscopy (1H-MRS) to obtain the bilateral metabolite levels in the lenticular nucleus of basal ganglia(BG). The ratios of N-acetylaspartate (NAA)/creatine (Cr) and Choline-containing compounds (Cho) /Cr ratios were calculated. Executive function was assessed by using the Wisconsin Card Sorting Test (WCST) and Trail Making Test, Part-B(TMT-B). ResultsThe comparison of biochemical changes showed that the NAA/Cr ratios in bilateral lenticular nucleus in both acute and euthymic BD patients was significantly lower than that in healthy controls at a confidence level of p<0.05. In the comparison of executive function, both acute and euthymic BD patients showed significantly decreased numbers of categories completed, and increased numbers of total errors, perseverative and noperseverative errors, and TMT-B uptake compared to the healthy controls at a confidence level of p<0.05. There were no significant differences between the acute BD and euthymic BD groups in the biochemical metabolite ratios and executive function. We found that the NAA/Cr ratio in the left in BG in the acute -episode BD patients was positively correlated with the number of categories completed, whereas it was negatively correlated with the total errors and TMT-B uptake. There was no correlation between the NAA/Cr and Cho/Cr ratios in the bilateral BG and the scores of SWCT and TMT-B in euthymic-episode BD patients. LimitationThe sample size was relatively small and not all the euthymic-episode patients are the ones with an acute episode. ConclusionsOur findings suggest that biochemical abnormalities in the lenticular nucleus and the executive dysfunction may occur early in the course of BD, and persist during remission, and are the most likely markers of endophenotypes of BD. The dysfunction of the neuronal function in the lenticular nucleus may be correlated with the cold dysfunction in patients with acute BD.