Multivoxel Magnetic Resonance Spectroscopy Research Articles

Investigation of Creatine Levels in Glial Tumors Using MR Spectroscopy

Purpose: The present study examines the efficacy of Creatine (Cr) levels in the determination of tumor grade on single-voxel (SV) and multi-voxel (MV) magnetic resonance spectroscopy (MRS) in patients with glial tumors. Material and Methods: A retrospective review was made of 20 SV and 20 MV MRS PDF images of patients with a pathological diagnosis of glial tumor. Cr values and metabolite ratios were measured in the tumor and compared with those in the healthy symmetrical brain parenchyma of the contralateral hemisphere. Results: A significant difference was noted in the (Cho+Cr)/NAA and Cho/NAA ratios on SV MRS between the high-grade tumors and the healthy contralateral hemisphere. On MV MRS, Cho/NAA ratios within the minimum and maximum Cr(h) voxels (Cho/NAAmin-Cr(h), Cho/NAAmax-Cr(h), respectively) were higher in high-grade tumors compared to healthy tissue. ROC analysis showed that the max-Cr(h) metabolite on MV MRS was successful in distinguishing low-grade tumors from high-grade tumors. Conclusion: Using the minimum and maximum values of Cr as a reference can improve the overall diagnostic accuracy in the diagnosis and grading of glial tumors. Our findings showed that Cr tended to be low in high-grade tumors and further that the max-Cr(h) metabolite may help in the differentiation of glial tumors on MV MRS.

Neurochemical and microstructural alterations in bipolar and depressive disorders: A multimodal magnetic resonance imaging study.

Depression in bipolar disorder (BD) is often misdiagnosed as unipolar depression (UD), leading to mistreatments and poor clinical outcomes in many bipolar patients. Herein, we report direct comparisons between medication-free patients with BD and those with UD in terms of the microstructure and neurometabolites in eight brain regions. A total of 20 patients with BD, 30 with UD patients, and 20 matched healthy controls (HCs) underwent 3.0T magnetic resonance imaging with chemical exchange saturation transfer (CEST) for glutamate (Glu; GluCEST) imaging, multivoxel magnetic resonance spectroscopy, and diffusion kurtosis imaging. Compared with HCs, patients with UD showed significantly lower levels of multiple metabolites, GluCEST% values, and diffusional kurtosis [mean kurtosis (MK)] values in most brain regions. In contrast, patients with BD presented significantly higher levels of Glu in their bilateral ventral prefrontal white matter (VPFWM), higher choline (Cho)-containing compounds in their left VPFWM and anterior cingulate cortex (ACC), and higher GluCEST% values in their bilateral VPFWM and ACC; moreover, reduced MK in these patients was more prominent in the left VPFWM and left thalamus. The findings demonstrated that both patients with UD and BD have abnormal microstructure and metabolic alterations, and the changes are not completely consistent in the prefrontal lobe region. Elevated Glu, Cho, and GluCEST% in the ACC and VPFWM of patients with UD and BD may help in differentiating between these two disorders. Our findings support the significance for the microstructural integrity and brain metabolic changes of the prefrontal lobe region in BD and UD.

Diagnostic performance of MRI perfusion and spectroscopy for brainstem glioma grading.

This study investigated the roles of dynamic susceptibility contrast (DSC) perfusion and multivoxel magnetic resonance spectroscopy (MRS) in grading brainstem glioma (BSG). Our retrospective study comprised 12 patients, including 6 with pathology verified low-grade BSGs and 6 with high-grade BSGs. We examined differences in age, relative cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and the metabolite ratios of choline (Cho)/N-acetyl aspartate (NAA) and Cho/creatine (Cr) between these two groups using the Mann-Whitney U test and Chi-square test. Receiver operating characteristic (ROC) curve analysis was used to establish cutoff values and assess their usefulness in grading BSG. The Cho/NAA metabolite ratio had the strongest preoperative predictive performance for identifying the correct histological grade among BSGs, with an area under the ROC curve (AUC) value of 0.944 (cutoff: 3.88, sensitivity [Se]: 83.3%; specificity [Sp]: 100%), followed by the Cho/Cr ratio (cutoff: 3.08; AUC: 0.917; Se: 83.3%; Sp: 100%), rCBF (cutoff: 3.56, AUC: 0.917; Se: 83.3%; Sp: 100%), rCBV (cutoff: 3.16, AUC: 0.889; Se: 100%; Sp: 66.7%), and age (cutoff: 9.5 years, AUC: 0.889; Se: 100%; Sp: 83.3%). rCBF and rCBV values comparing solid tumors with the normal brain parenchyma and the metabolite ratios for Cho/NAA and Cho/Cre may serve as useful indices for establishing BSG grading and provide important information when determining treatment planning and prognosis in patients with BSG.

Multiparametric Characterization of Intracranial Gliomas Using Dynamic [18F]FET-PET and Magnetic Resonance Spectroscopy.

Both static and dynamic O-(2-[18F]fluoroethyl)-l-tyrosine-(FET)-PET and 1H magnetic resonance spectroscopy (MRS) are useful tools for grading and prognostication in gliomas. However, little is known about the potential of multimodal imaging comprising both procedures. We therefore acquired NAA/Cr and Cho/Cr ratios in multi-voxel MRS as well as FET-PET parameters in 67 glioma patients and determined multiparametric parameter combinations. Using receiver operating characteristics, differentiation between low-grade and high-grade glioma was possible by static FET-PET (area under the curve (AUC) 0.86, p = 0.001), time-to-peak (TTP; AUC 0.79, p = 0.049), and using the Cho/Cr ratio (AUC 0.72, p = 0.039), while the multimodal analysis led to improved discrimination with an AUC of 0.97 (p = 0.001). In order to distinguish glioblastoma from non-glioblastoma, MRS (NAA/Cr ratio, AUC 0.66, p = 0.031), and dynamic FET-PET (AUC 0.88, p = 0.001) were superior to static FET imaging. The multimodal analysis increased the accuracy with an AUC of 0.97 (p < 0.001). In the survival analysis, PET parameters, but not spectroscopy, were significantly correlated with overall survival (OS, static PET p = 0.014, TTP p = 0.012), still, the multiparametric analysis, including MRS, was also useful for the prediction of OS (p = 0.002). In conclusion, FET-PET and MRS provide complementary information to better characterize gliomas before therapy, which is particularly interesting with respect to the increasing use of hybrid PET/MRI for brain tumors.

Magnetic resonance spectroscopy associations with clinicopathologic features of estrogen-dependent endometrial cancer

BackgroundWe studied the magnetic resonance spectroscopy (MRS) associations with clinicopathologic features of estrogen-dependent endometrial cancer (type I EC).MethodsTotally 45 patients with type I EC who underwent preoperative multi-voxel MRS at 3.0 T were enrolled. The mean ratio of the Cho peak integral to the unsuppressed water peak integral (Cho/water) of the tumor was calculated. The Cho/water and apparent diffusion coefficient (ADC) of type I EC with and without local invasion, as well as with different levels of Ki-67 staining index (SI) (≤ 40% and > 40%), were compared. Correlation test was used to examine the relationship of Cho/water, as well as mean ADC, with Ki-67 SI, tumor stage, and tumor grade.ResultsThe mean Cho/water of EC with Ki-67 SI ≤ 40% (2.28 ± 0.93) × 10−3 was lower than that with Ki-67 SI > 40% (4.08 ± 1.00) × 10−3 (P < 0.001). The mean Cho/water of EC with deep and superficial myometrial invasion was (3.41 ± 1.26) × 10−3 and (2.43 ± 1.11) × 10−3, respectively (P = 0.011). There was no significant difference in Cho/water between type I EC with and without cervical invasioin ([2.68 ± 1.00] × 10−3 and [2.77 ± 1.28] × 10−3, P = 0.866). The mean Cho/water of type I EC with and without lymph node metastasis was (4.02 ± 1.90) × 10−3 and (2.60 ± 1.06) × 10−3, respectively (P = 0.014). The Cho/water was positively correlated with the Ki-67 SI (r = 0.701, P < 0.001). There were no significant differences in ADC among groups (all P > 0.05).ConclusionMRS is helpful for preoperative assessment of clinicopathological features of type I EC.

Diagnostic Accuracy of Magnetic Resonance Spectroscopy in Predicting the Grade of Glioma Keeping Histopathology as the Gold Standard.

BackgroundGliomas are the most prevalent intrinsic tumors of the central nervous system and are categorized from grade I to grade IV. Magnetic resonance imaging (MRI) provides exact diagnosis, prognosis, and assessment of tumor response to current chemotherapy/immunotherapy and radiation therapy. With histopathology serving as the gold standard, we aimed to assess the diagnostic accuracy of magnetic resonance spectroscopy (MRS) in predicting glioma grade.MethodologyThis cross-sectional study was conducted in the Department of Radiology, KRL Hospital, Islamabad, from December 15, 2019, to September 30, 2021. After providing written consent, 80 patients with untreated gliomas were included in this study. The voxel of interest was identified using MRI brain conventional contrast-enhanced sequences to assess the grade of the gliomas and link it to the histology report. Following this identification, tissue metabolites were calculated using MRS.ResultsThe patients’ age ranged from 13 to 80 years, with a mean age of 49.5 years. Male patients comprised 57.5% of the total study population, while female patients comprised 42.5%. Overall, 23.75% of patients had low-grade tumors, while 76.25% had high-grade tumors. Low-grade tumors had a choline (Cho)/creatine (Cr) metabolite ratio of 1.7421, whereas high-grade tumors had an average Cho/Cr metabolite ratio of 2.5575. N-acetyl aspartate (NAA)/Cr ratio was 1.6368 in low grade and 0.6734 in high-grade tumors. Sensitivity of 77% and specificity of 84.2% were noted, with 78.75% diagnostic accuracy for the Cho/Cr ratio.ConclusionsMultivoxel MRS has been shown to reliably predict the grade of gliomas despite its non-invasive nature and lack of procedural challenges. When used together Cho/Cr and NAA/Cr ratios and histopathology can accurately determine tumor grade and can be used as a supplementary non-invasive technique.

A prospective study to evaluate the role of multiparametric magnetic resonance imaging in the grading of gliomas using magnetic resonance imaging perfusion and diffusion and multivoxel magnetic resonance spectroscopy

Abstract Background: The primary aim of this study was to evaluate the individual and combined efficacy of magnetic resonance imaging (MRI) parameters, which include MRI perfusion, MRI diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) in the grading of gliomas as low grade versus high grade. The pre-operative imaging-based grading of gliomas by multiparametric MRI was compared with the gold standard histopathological studies. Methods: A total of 22 patients referred to the radiology department for multiparametric MRI of the brain with presumptive diagnosis of glioma on computed tomography/MRI were included in the study. Conventional T1, T2 and fluid-attenuated inversion recovery images were obtained followed by perfusion MRI using gadopentetate dimeglumine (Magnevist) administration. This was followed by DWI and MRS. Results: Our statistical analysis demonstrated that a cut-off of apparent diffusion coefficient value of 954.085 (10–6 mm2/Sec) provides a sensitivity and specificity of 87.5% and 85.7%, respectively, in differentiating low-grade gliomas (LGGs) from high-grade gliomas (HGGs). A choline/creatine ratio cut-off value of 2 provides sensitivity and specificity of 100% and 92.9%, respectively, while a cut-off value of 1.45 of choline/N-acetylaspartate ratio provides both sensitivity and specificity of 100% in differentiating LGG from HGG. A cut-off of 1.9 for maximum relative cerebral blood volume (rCBV) value provides both sensitivity and specificity of 100% in differentiating LGGs from HGGs. Conclusions: We concluded that perfusion MRI (rCBV) was the best parameter among perfusion MRI, DWI and MRI spectroscopy in differentiating HGGs from LGGs. Combined multiparametric results showed a diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of 86.4%, 82.4%, 100%, 100% and 62.5%, respectively, on comparison with gold standard histopathological grading.

Sequential Diffusion Tensor Imaging and Magnetic Resonance Spectroscopy in Patients Undergoing Reirradiation for Progressive Diffuse Intrinsic Pontine Glioma

PurposeDiffusion tensor imaging for evaluation of white matter tracts is used with magnetic resonance spectroscopy (MRS) to improve management of diffuse intrinsic pontine glioma (DIPG). Changes in the apparent diffusion coefficient (ADC), fractional anisotropy (FA), and tumor metabolite ratios have been reported after initial radiation for DIPG, but these markers have not been studied sequentially in patients undergoing reirradiation for progressive DIPG. Here, we report a case series of 4 patients who received reirradiation for progressive DIPG on a prospective clinical trial in which we evaluated quantitative changes in FA, ADC, and tumor metabolites and qualitative changes in white matter tracts. Methods and MaterialsThe median reirradiation dose was 25.2 Gy (24-30.8 Gy). Fiber tracking was performed using standard tractography analysis. The FA and ADC values for the corticospinal and medial lemniscus tracts were calculated before and after reirradiation. Multivoxel MRS was performed. Findings were correlated with clinical features and conventional MRI of tumors. ResultsAll patients had an initial response to reirradiation as shown by a decrease in tumor size. In general, FA increased with disease response and decreased with progression, whereas ADC decreased with disease response and increased with progression. At second progression, the FA fold change relative to values during disease response decreased in both patients with available imaging at second progression. Visualization of tracts demonstrated robust reconstitution of previously disrupted paths during tumor response; conversely, there was increased fiber tract disruption and infiltration during tumor progression. The MRS analysis revealed a decrease in choline:creatinine and choline:N-acetylaspartate ratios during tumor response and increase during progression. ConclusionsDistinct changes in white matter tracts and tumor metabolism were observed in patients with DIPG undergoing reirradiation on a prospective clinical trial. Changes related to tumor response and progression were observed after 24 to 30.8 Gy reirradiation.

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.

Axonal dysfunction is associated with interferon-γ levels in childhood-onset systemic lupus erythematosus: a multivoxel magnetic resonance spectroscopy study.

Axonal/neuronal damage has been shown to be a pathological finding that precedes neuropsychiatric manifestations in SLE. The objective of this study was to determine the presence of axonal dysfunction in childhood-onset SLE patients (cSLE) and to determine clinical, immunological and treatment features associated with its occurrence. We included 86 consecutive cSLE patients [median age 17 (range 5-28) years] and 71 controls [median age 18 (5-28) years]. We performed proton magnetic resonance spectroscopic imaging using point resolved spectroscopy sequence over the superior-posterior region of the corpus callosum and signals from N-acetylaspartate (NAA), choline-based (CHO), creatine-containing (Cr), myo-inositol (mI), glutamate, glutamine and lactate were measured and metabolites/Cr ratios were determined. Complete clinical, laboratory and neurological evaluations were performed in all subjects. Serum IL-4, IL-5, IL-6, IL-10, IL-12, IL-17, TNF-α and INF-γ cytokine levels, antiribosomal P protein antibodies (anti-P) and S100β were measured by ELISA using commercial kits. Data were compared by non-parametric tests. NAA/Cr ratios (P = 0.035) and lactate/Cr ratios (P = 0.019) were significantly decreased in cSLE patients when compared with controls. In multivariate analysis, IFN-γ levels [odds ratio (OR) = 4.1; 95% CI: 2.01, 7.9] and depressive symptoms (OR = 1.9; 95% CI: 1.1, 3.2) were associated with NAA/Cr ratio. Increased CHO/Cr was associated with the presence of cognitive impairment (OR = 3.4; 95% CI: 2.034, 5.078; P < 0.001). mI/Cr ratio correlated with cumulative glucocorticoids dosage (r = 0.361, P = 0.014). NAA and CHO ratios may be useful as biomarkers in neuropsychiatric cSLE. Longitudinal studies are necessary to determine whether they predict structural damage.

Contribution of spectroscopic magnetic resonance imaging to target volume delineation in Gamma Knife Radiosurgery: Myth or reality?

Brain malignancies are still associated with poor prognosis despite multimodal radiosurgical therapeutic approach using Gamma Knife (GK), CyberKnife (CK), and linear accelerator-based technologies [1]. These advances have significantly improved the treatment outcome. However, the surgical and radiosurgical concept is still “image-guided”, and the success is closely related to precise tumor volume definition. The gross tumor volume (GTV) is defined as the visible contrast- enhancing lesion on magnetic resonance (MR) images with high three-dimensional spatial accuracy. Target delineation requires always both T2-weighted and volumetric T1-weighted sequences. T2-weighted fluid attenuated inversion recovery (FLAIR) sequences analyze the lesions surrounding brain tissues [2,3]. Objective assessment of apparently healthy tissue surrounding brain tumors seems to be a considerable factor interfering not only with the radiosurgical procedure, but also with the recurrence rate and overall survival. Several studies identified infiltrative spectroscopic pattern of the perilesional edema in more than 96% of high-grade gliomas cases and in 11,5% of patients with brain metastasis [4]. Moreover, some autopsy series of brain metastases confirmed infiltrative growth in radiologically healthy surrounding tissues in more than 60% of cases. This unseen malignant component is responsible of 80 % of “early recurrence” which should be considered as natural evolution of the main tumor [5]. In the management of high grade gliomas, the radiosurgeons are faced either to carcinologic incomplete procedures or to overestimated target irradiation with unbalanced benefit/risk action mostly related to radiation-induced brain necrosis [6]. The delineation of clinical target volume (CTV) which is defined as the volume of tissue that contains the GTV and any microscopic tumor or paths of spread, became a standard for any radio-surgical planning. Since a decade, the magnetic resonance spectroscopy (MRS) was standardized in the target volume assessment. The aim is to establish a metabolic lesional cartography. It had been reported that choline/ N- acetylaspartate (NAA) multivoxel MR spectroscopy index higher that 2,5 is in favor of malignancy in glioma with sensitivity of 90 % and specificity of 85 % [7]. However, NAA/Creatine (Cr) and Choline/Cr ratios are more relevant in the analysis of perilesional edema in brain metastasis cases. The introduction of MRS metabolic cartography concept, the use of relevant metabolite and adapted metabolites ratio estimation contributed to precision in radiosurgery. However, MRS is not used for target delineation for Gamma Knife radiosurgical treatment because of its incompatibility with the Leksell Gamma Knife planning software. Recently, we described the development of the first software allowing the integration of metabolic cartography based on multivoxel spectroscopic MRI in the radiosurgical planning for Leksell Gamma Knife Radiosurgery. The few existing meta-analysis could not lead to gold standard volume delineation techniques despite objective advance in imaging assessment [8,9]. Prospective studies using multimodal imaging data will help to overcome this insufficiency for target delineation in radiosurgery

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.

Proton MR spectroscopic features of the cisternal segment of the trigeminal nerve in patients with trigeminal neuralgia: A pilot study

PurposeTo investigate normal quantitative proton magnetic resonance spectroscopy (MRS) features of the cisternal segment of the trigeminal nerve and evaluate possible metabolite concentration differences in the affected and unaffected nerves of trigeminal neuralgia patients. Material and methodsA total of 33 consecutive patients who underwent a MR study of the internal auditory canal/posterior fossa and dedicated trigeminal nerve multivoxel MRS were enrolled. Measurements of N-acetyl aspartate (NAA), creatine (Cr), choline (Cho), myoinositol (mI), glutamate-glutamine (Glx) concentrations, and ratios of NAA-to-Cr, Cho-to-Cr, and Cho-to-NAA were automatically calculated by the dedicated software. Vascular conflicts were also recorded. ResultsThe mean Cr concentration was significantly higher on the affected sides in all parts of the nerve (p < 0.05), while the mean NAA concentration was significantly higher in only the distal portion (p = 0.04). Mean mI concentration was significantly higher in the middle and distal parts (p < 0.05). NAA-to-Cr ratio was significantly higher in the proximal and middle parts (p < 0.05), while Cho-to-Cr ratio was significantly higher only in the middle portion (p = 0.028). Finally, the Cho-to-NAA ratio was significantly higher only in the distal portion (p = 0.04). Vascular conflicts were observed in 24 patients (72.7%), and in 20 of them (60.6%) the conflict was on the same side as the neuralgia symptoms. ConclusionAlthough the detected statistical relationships were variable in the spectroscopic measurements, metabolite concentrations and ratios were successfully exhibited in all patients. Features of a normal trigeminal nerve were able to determine by MRS. All calculated metabolite concentrations were higher in the affected nerves; however, only some of them were statistically significant. No statistically significant relationships were found between the MRS measurements and nerves with and without vascular compression.

Neuroimaging Findings in Glaucoma (Proton Magnetic Resonance Spectroscopy Study)

The aim of the research is to determine metabolic changes in brain tissue by magnetic resonance spectroscopy (MRS) for patients who had primary open angle glaucoma (POAG) and to reveal a correlation between morphometric and functional alterations in the optic nerve and retina with basic MRS data. Methods: The study involved 24 patients with a diagnosis of POAG aged 58 to 80 years (mean age 73.2 ± 9.5 years). All patients underwent verification of the diagnosis of POAG, quantitative static perimetry (indexes were evaluated: MD - mean deviation), optical coherence tomography of the retina (assessment of the area of the neuro-retinal rim (NRR) and the thickness of the nerve fibers’ layer of the retina (RNFL)). The 2D-PRESS (Point RESolved Spectroscopy) volume-selection method was used for multivoxel MRS, TE (Time Echo) = 144ms TR (Time Repetition) = 2s, the size of each voxel was 10 * 10 * 15mm. The region of interest included thalami (4 voxels in each thalamus) and occipital cortex; Cho/Cr, NAA/Cr and NAA/Cho were evaluated. Results: According to analysis of variance, the ratio of NAA/Cr in the right thalamus was associated with the POAG stage of the right eye (F = 5.006; p = 0.0173) and decreased with increasing of the disease stage. At the same time, there were no significant differences in different stages of POAG of the left eye (F = 1.337; p = 0.285). The ratio of NAA/Cr in the left thalamus did not differ depending on the POAG stage of the right eye (F = 1.337; p = 0.285) but depended on the stage of POAG of the left eye (F = 6.245; p = 0.0074). Thus, the eye POAG stage affected the ratio of NAA/Cr in the ipsilateral thalamus, but not in the contralateral one. It was also revealed that the ratio of NAA/Cr in the right occipital cortex correlated positively with the area of the NRR and MD of the left eye (r = 0.54; p = 0.0069 and r = 0.54; p = 0.0260, respectively). Conclusions: The decline of NAA/Cr ratio in thalamus and occipital cortex is observed in patients with primary open-angle glaucoma, which confirms the impairment of functional state of these brain structures and may indicate the neurodegeneration in the central part of visual system in patients with POAG. The correlations of the stage of primary open-angle glaucoma and the Cho/Cr ratio and NAA/Cr ratio in thalamus were revealed, which could have diagnostic and prognostic value in POAG. The dependence of the ratio of NAA/Cr in the thalamus and occipital cortex and morphometric data of the optic disc and the functional state of the retina was determined, which confirms the involvement of the optic tract in the POAG progression and its possible development.

Prognostication of Recovery of Consciousness in Patients in a Vegetative State Using Proton Magnetic Resonance Spectroscopy

Objectives. To study the predictive significance of proton magnetic resonance spectroscopy (MRS) in patients in a vegetative state. Materials and methods. Multivoxel MRS was carried out in 34 patients in a vegetative state with voxels in the thalamus, globus pallidus, putamen, internal capsule, fornix, brainstem, and the temporal and frontal areas of the cortex. Patients were divided into groups depending on the etiology of vegetative state: 22 patients had the sequelae of traumatic brain injury (TBI) and 12 patients had the sequelae of hypoxic brain damage. The groups were comparable in terms of age and the duration of the vegetative state (mean 2.3 months). Neurological status was assessed both during the hospitalization period and at 6–12 months using the Coma Recovery Scale (CRS-R). MRS results obtained at 6–12 months were compared with baseline data. The outcome of patients with the sequelae of TBI were as follows: persistent vegetative state in six patients, minimally conscious state plus in nine patients, recovery from the state of minimal consciousness in seven. Outcomes of patients with the sequelae of hypoxia were: persistent vegetative state in 10 patients and minimally conscious state plus in two. Results. Decreases in the N-acetylaspartate/creatinine ratio in the thalamus, internal capsule, and temporal cortex correlated with poor outcomes in both groups, while higher values correlated with further recovery of consciousness. Decreases in the N-acetylaspartate/creatinine ratio and the N-acetylaspartate/N-acetylaspartate + choline + creatine ratio in the midbrain correlated with poor outcomes only in patients with the sequelae of hypoxia. Conclusions. The results obtained here suggest that MRS provides a more accurate determination of the outcome in patients with hypoxic brain damage and patients with TBI, who showed recovery of consciousness to the level of coming out of the vegetative state.

Significance of single and multi-voxel 1H magnetic resonance spectroscopy in the quantification of myocellular lipid in young non-obese Asian Indian males

To prospectively assess intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) using single voxel spectroscopy (SVS) and multi voxel magnetic resonance spectroscopy (MVS) in soleus muscle and correlate results with metabolic variables in non-obese (BMI < 23 kg/m2) Asian Indian males. Thirty one patients with diabetes (cases) and twelve normoglycaemic subjects (controls) underwent point resolved spectroscopy sequence (PRESS) of soleus muscle using SVS and MVS in a 3 T MRI scanner. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured from MRI images and body composition was measured from dual-energy x-ray absorptiometry (DXA). The mean IMCL from SVS and MVS were 1.6% and 2.6% in cases and 2.3% and 3.4% in controls respectively. The mean EMCL from SVS and MVS were 1.8% and 3% in cases and 1.5% and 3% respectively in controls. A significant correlation between IMCL and total fat mass (rho = 0.42, p < 0.01) and total body fat (rho = 0.46; p < 0.01) were observed in cases while using the SVS technique and no correlations were found in the MVS technique. The SVS showed significant correlations between total myocellular lipids with VAT and SAT in cases alone. Total myocellular lipids acquired using both techniques showed a significant correlation with BMI, waist circumference, total fat mass, total body fat and truncal fat in cases alone. Quantification of IMCL of soleus muscle using the SVS technique is useful in studying the relationship with metabolic markers in non-obese Asian Indians with diabetes.

Chemotherapy-related cognitive impairment in patients with breast cancer based on MRS and DTI analysis.

The purpose of this study is to investigate chemotherapy-related cognitive impairment (CRCI) in breast cancer patients, analyze absolute concentration and structural changes of metabolites in different brain regions by multimodal neuroimaging technology, and explore correlation between them. Breast cancer patients with chemotherapy treatment group (Ctx+, N = 24) and control group without treatment (Ctx-, N = 20) underwent neuropsychological tests, multivoxel magnetic resonance spectroscopy (MRS), and diffusion tensor imaging (DTI) before and after chemotherapy. Regions of interest (ROls) in magnetic resonance scan include bilateral posterior cingulate gyrus (PCG), bilateral dorsal thalamus (DT), bilateral lenticular nucleus (LN), bilateral posterior horn of the lateral ventricle paratrigonal white matter (PWM). In MRS, absolute concentrations of N-acetylaspartate (NAA), myo-inositol (MI), choline-containing compounds (Cho), total creatine (tCr), glutamine + glutamate (Glx) were quantified using LC Model and SAGE software. In DTI, we used fractional anisotropy (FA) and mean diffusivity (MD) to reflect white matter integrity. In Ctx+ patients, scores of functional assessment of cancer treatment cognition test (FACT-Cog), perceived cognitive impairments (PCI), impact of perceived impairments on quality of life (QOL), perceived cognitive abilities (PCA), auditory-verbal learning test (AVLT) recognition and clock drawing test (CDT) were lower than those before chemotherapy (p < 0.05). In MRS, Ctx+ patients had significantly lower NAA values in bilateral PCG, DT, respectively. The concentrations of tCr were observed to decline in bilateral PCG and right DT. Glx values decreased in right DT. Cho values decreased significantly in bilateral DT. In DTI, Ctx+ patients had lower FA values in bilateral PCG compared with patients before chemotherapy. Among imaging metrics and cognitive scores, positive correlations were observed between changes in AVLT recognition scores and changes in NAA values in bilateral PCG (left PCG: r = 0.470, p < 0.01; right PCG: r = 0.500, p < 0.01). Positive correlations were also found between changes in AVLT recognition and changes in FA values in bilateral PCG (left PCG: r = 0.513, p < 0.01; right PCG: r = 0.563, p < 0.01). Chemotherapy can lead to a decrease in memory function, accompanied by changes in brain metabolite concentration and white matter integrity in some parts of brain.

PROSEDUR PEMERIKSAAN MAGNETIC RESONANCE SPECTROSCOPY (MRS) KEPALA PADA KASUS TUMOR OTAK DI INSTALASI RADIOLOGI RSUD PETALA BUMI PEKANBARU

Background: Magnetic resonance spectroscopy is the head of the advance MRI examination to assess metabolite in a network, whether it is normal or abnormal tissue one of which is the tumor tissue. Brain tumors can also come from other organ metastases such as lung, breast or nasopharyngeal cancer. The purpose of this study was to determine the examination procedure, the reason for the use of techniques and the role of multi-voxel magnetic resonance spectroscopy in the case of a brain tumor in diagnosis in Radiology Hospital Petala Bumi Pekanbaru.&#x0D; Methods: This type of research is qualitative with case study approach. Data was collected in May-June 2017 at Radiology Installation of Petala Bumi Pekanbaru with observation methods, interviews with radiographers, radiology specialists and sending doctors and documentation. Data obtained from the study were analyzed with interactive models, creating a transcript of the interview then reduced and processed in the form of open coding, presented in the form of quotes and then it can be concluded.&#x0D; Result &amp; Conclusion: The results of this study stated that the examination procedure Magnetic resonance spectroscopy (MRS) head in the case of brain tumors using standard protocols MRI Head namely Axial T1, Axial T2 PROPELLER, Axial T2 FLAIR PROPELLER, Axial DWI, T1 PERFUSSION, Sagittal T2 FSE, Coronal T2 FSE, And 3D TOF MRA. After contrast the contrast was made again Axial T1, Sagital T1, Coronal T1 and created spectroscopy with multi voxel technique. Multi-voxel spectroscopy techniques used can help to see the value of metabolites present in the area around the tumor and the tumor was itself and can diagnose and help doctors do a biopsy.

Magnetic resonance spectroscopy in Parkinson’s disease

Introduction. Modern neuroimaging methods allow to evaluate in vivo biochemical processes in the brain. Such methods include magnetic resonance spectroscopy (MRS) and positron emission tomography (PET). While PET is the “golden standard” in assessing the brain functional state and is widely used in neurodegenerative diseases, the diagnostic value of MRS remains undefined due to the inconsistency of the results obtained in different studies. At the same time, MRC allows obtaining information on the content of many metabolites in living tissues, including N-acetyl aspartate (NAA), which is considered to be a surrogate marker of neuronal integrity, choline (Cho), associated with membrane metabolism, Cr - energy metabolism, etc. The aim of this study is to compare MRS and PET data in patients with Parkinson’s disease (PD).Materials and methods. Twenty-six patients with PD stages I to III according to the Hoehn and Yahr Scale and age-matching control group of neurologically and cognitively intact people were examined. All patients underwent neurological examination, a multivoxel MRS of the supraventricular region, including white and gray matter, and PET with 18F-fluorodeoxyglucose (FDG) to assess cerebral metabolic rate of glucose (CMRglu).Results. Decrease of NAA/Cr and NAA/Cho in the white matter in the left hemisphere was revealed in PD group compared to control, with the NAA/Cr ratio negatively correlating with the stage of the disease of the Hoehn and Yahr Scale. The NAA content in the white matter and the cingulate cortex positively correlated with CMRglu in Brodmann fields 5–7, 8–10, 22, 23, 46. At the same time, Cho/Cr ratio negatively correlated with CMRglu in the cortical areas associated with the development of cognitive impairment in PD (Brodman areas 9, 10, 39, 47).

Hippocampal GABA levels correlate with retrieval performance in an associative learning paradigm

Neural plasticity is a complex process dependent on neurochemical underpinnings. Next to the glutamatergic system which contributes to memory formation via long-term potentiation (LTP) and long-term depression (LTD), the main inhibitory neurotransmitter, GABA is crucially involved in neuroplastic processes. Hence, we investigated changes in glutamate and GABA levels in the brain in healthy participants performing an associative learning paradigm.Twenty healthy participants (10 female, 25 ± 5 years) underwent paired multi-voxel magnetic resonance spectroscopy imaging before and after completing 21 days of a facial associative learning paradigm in a longitudinal study design. Changes of GABA and glutamate were compared to retrieval success in the hippocampus, insula and thalamus.No changes in GABA and glutamate concentration were found after 21 days of associative learning. However, baseline hippocampal GABA levels were significantly correlated with initial retrieval success (pcor = 0.013, r = 0.690). In contrast to the thalamus and insula (pcor>0.1), higher baseline GABA levels in the hippocampus were associated with better retrieval performance in an associative learning paradigm.Therefore, our findings support the importance of hippocampal GABA levels in memory formation in the human brain in vivo.