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Objective: Many patients with long COVID experience neurological and psychological symptoms. Signal abnormalities on MR images in the corpus callosum have been reported. Knowledge about the metabolic profile in the splenium of the corpus callosum (CCS) may contribute to a better understanding of the pathophysiology of long COVID. Materials and methods: Eighty-one subjects underwent proton MR spectroscopy examination. The metabolic concentrations of total N-acetylaspartate (NAA), choline-containing compounds (Cho), total creatine (Cr), myo-inositol (mI), and NAA/Cho in the CCS were statistically compared in the group of patients containing 58 subjects with positive IgG COVID-19 antibodies or positive SARS-CoV-2 qPCR test at least two months before the MR and the group of healthy controls containing 23 subjects with negative IgG antibodies. Results: An age-dependent effect of SARS-CoV-2 on Cho concentrations in the CCS has been observed. Considering the subjective threshold of age = 40 years, older patients showed significantly increased Cho concentrations in the CCS than older healthy controls (p = 0.02). NAA, Cr, and mI were unchanged. All metabolite concentrations in the CCS of younger post-COVID-19 patients remained unaffected by SARS-CoV-2. Cho did not show any difference between symptomatic and asymptomatic patients (p = 0.91). Discussion: Our results suggest that SARS-CoV-2 disproportionately increases Cho concentration in the CCS among older post-COVID-19 patients compared to younger ones. The observed changes in Cho may be related to the microstructural reorganization in the CCS also reported in diffusion measurements rather than increased membrane turnover. These changes do not seem to be related to neuropsychological problems of the post-COVID-19 patients. Further metabolic studies are recommended to confirm these observations. [ABSTRACT FROM AUTHOR]

Nanotechnology-based photothermal therapy (NPTT) is a new emerging modality of cancer therapy. To have the right prediction and early detection of response to NPTT, it is necessary to get rapid feedback from a tumor treated by NPTT procedure and stay informed of what happens in the tumor site. We performed this study to find if proton magnetic resonance spectroscopy (1H-MRS) can be well responsive to such an imperative requirement. We considered various treatment groups including gold nanoparticles (AuNPs), laser, and the combination of AuNPs and laser (NPTT group). Therapeutic effects on CT26 colon tumor-bearing BALB/c mice were studied by looking at alterations that happened in 1H-MRS signals and tumor size after conducting treatment procedures. In MRS studies, the alterations of choline and lipid concentrations and their ratio were investigated. Having normalized the metabolite peak to water peak, we found a significant decrease in choline concentration post-NPTT (from (1.25 ± 0.05) × 10−3 to (0.43 ± 0.04) × 10−3), while the level of lipid concentration in the tumor was slightly increased (from (2.91 ± 0.23) × 10−3 to (3.52 ± 0.31) × 10−3). As a result, the choline/lipid ratio was significantly decreased post-NPTT (from 0.41 ± 0.11 to 0.11 ± 0.02). Such alterations appeared just 1 day after NPTT. Tumor shrinkage in all groups was studied and significant changes were significantly detectable on day 7 post-NPTT procedure. In conclusion, the study of choline/lipid ratio using 1H-MRS may help us estimate what happens in a tumor treated by the NPTT method. Such an in vivo assessment is interestingly feasible as soon as just 1 day post-NPTT. This would undoubtedly help the oncologists make a more precise decision about treatment planning strategies. [ABSTRACT FROM AUTHOR]

The study was aimed to the analysis of correlations between anatomic brain parameters and characteristics of neurophysiological and metabolic supportive mechanisms of cognitive functions in the patients with ultra-high risk of schizophrenia. The study comprised 30 young male patients and 30 age- and sexmatched mentally healthy subjects. We used the methods of diffusion-weighted tomography, single voxel proton MR spectroscopy, and oddball ERP recording. The statistically significant intergroup differences in the structural connectivity were confirmed in the anterior thalamic radiation of the left hemisphere. The diffusion abnormalities in this area were correlated with P300 latencies and the level of γ-aminobutyric acid (GABA). [ABSTRACT FROM AUTHOR]

Introduction: We examined the effect of maturation on the regional distribution of brain metabolite concentrations using multivoxel chemical shift imaging. Methods: From our pool of pediatric MRI examinations, we retrospectively selected patients showing a normal cerebral MRI scan or no pathologic signal abnormalities at the level of the two-dimensional 1H MRS-CSI sequence and an age-appropriate global neurological development, except for focal neurological deficits. Seventy-one patients (4.5 months-20 years) were identified. Using LC Model, spectra were evaluated from voxels in the white matter, caudate head, and corpus callosum. Results: The concentration of total N-acetylaspartate increased in all regions during infancy and childhood except in the right caudate head where it remained constant. The concentration of total creatine decreased in the caudate nucleus and splenium and minimally in the frontal white matter and genu. It remained largely constant in the parietal white matter. The concentration of choline-containing compounds had the tendency to decrease in all regions except in the parietal white matter where it remained constant. The concentration of myoinositol decreased slightly in the splenium and right frontal white matter, remained constant on the left side and in the caudate nucleus, and rose slightly in the parietal white matter and genu. Conclusion: CSI determined metabolite concentrations in multiple cerebral regions during routine MRI. The obtained data will be helpful in future pediatric CSI measurements deciding whether the ratios of the main metabolites are within the range of normal values or have to be considered as probably pathologic. [ABSTRACT FROM AUTHOR]

Objective: To assess short- and long-term reproducibility of marrow adipose tissue (MAT) quantification by 1H-MR spectroscopy.Materials and Methods: Our study was IRB-approved and HIPAA compliant. Written informed consent was obtained. We studied 20 overweight/obese but otherwise healthy subjects (12 female, 8 male) with a mean age of 37 ± 6 years. All subjects underwent proton magnetic resonance spectroscopy (1H-MRS) of the fourth lumbar vertebral body using a single-voxel point-resolved spatially localized spectroscopy sequence without water suppression at 3 T. Measurements were repeated after 6 weeks and 6 months using identical scanning protocols. The following clinical parameters were collected, weight, BMI, exercise status, and trabecular bone mineral density (BMD), by quantitative computed tomography. Short- (baseline, 6 weeks) and long-term (baseline, 6 months) reproducibility of MAT was assessed by the coefficient of variance (CV), standard deviation (SD), and interclass correlation coefficients (ICCs). Short- and long-term changes in clinical parameters were assessed by paired t-test.Results: For short-term reproducibility between baseline and 6-week scans, the CV was 9.9 %, SD was 0.08, and ICC was 0.97 (95 % CI 0.94-099). For long-term reproducibility between baseline and 6-month scans, the CV was 12.0 %, SD was 0.10, and ICC was 0.95 (95 % CI 0.88 to 0.98). There was no significant short- or long-term change in clinical parameters (weight, BMI, exercise status, BMD) (p > 0.2).Conclusion: 1H-MRS is a reproducible method for short- and long-term quantification of MAT. Our results can guide sample size calculations for interventional and longitudinal studies. [ABSTRACT FROM AUTHOR]

Objects: Hepatic and pancreatic fat content become increasingly important for phenotyping of individuals with metabolic diseases. This study aimed to (1) evaluate hepatic fat fractions (HFF) and pancreatic fat fractions (PFF) using H magnetic resonance spectroscopy (MRS) and the recently introduced fast mDixon method, and to examine body fat effects on HFF and PFF, (2) investigate regional differences in HFF and PFF by mDixon. Materials and methods: HFF and PFF were quantified by mDixon with two flexible echo times and by single voxel H MRS in 24 healthy subjects. The regional differences of PFF within the pancreas were assessed with mDixon. Abdominal visceral and subcutaneous fat was assessed by T1-weighted MRI at 3T. Results: Both methods correlated well for quantification of HFF ( r = 0.98, p < 0.0001) and PFF ( r = 0.80, p < 0.0001). However, mDixon showed a higher low limit in HFF and PFF. PFF showed no regional differences using mDixon. In addition, both visceral and subcutaneous fat correlated with pancreatic fat, while only visceral fat correlated with liver fat, employing both H MRS and mDixon. Conclusion: The novel and fast two-point mDixon exhibits a good correlation with the gold-standard H MRS for assessment of HFF and PFF, with limited sensitivity for assessing lower fat content. [ABSTRACT FROM AUTHOR]

Choline and lipid lactate peaks elevated in a number of intracranial space occupying lesions, in endemic area tuberculosis should be considered. Choline peak along with lipid lactate elevation is non-specific and can be seen in a number of other conditions like high-grade gliomas, Metastases, lymphomas and demyelinating disorders. We present a case of 45 year old gentle man known case chest tuberculosis on treatment default presenting with multiple intracranial lesions showing lipid-choline elevation. [ABSTRACT FROM AUTHOR]

The biochemical (proton MR spectroscopy data) and hemodynamic (fMRI data) characteristics of the functional state of the prefrontal cortex were studied in seven patients with juvenile episodic schizophrenia in the state of remission after the first episode and in eight healthy subjects of similar gender and age. There were no differences between groups in terms of the parameters studied, though parameters were related to the severity of psychopathological symptomatology in patients, as evaluated on the PANSS. [ABSTRACT FROM AUTHOR]

We report a new case of infantile idiopathic hemiconvulsion–hemiplegia syndrome (HH). A prolonged right-sided febrile convulsion was followed 4 days later, by right hemiconvulsive status epilepticus, documented by video-electroencephalogram (EEG) recording. The child developed an ipsilateral hemiplegia, partially improved during the first month of follow-up. Sequential cerebral magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS) at 6, 15, 30 days of follow-up showed a cytotoxic edema in the left hemisphere and a subsequent necrosis. At 1-year of follow-up, we performed MRI control because of febrile convulsion lasting few minutes that confirmed a non-progressive left hemisphere atrophy. After 2 years, the patient was seizure-free, with a mild right hemiplegia and language skills deficit. We discuss the unclear pathogenesis of HH through sequential neuroradiological evaluation. [ABSTRACT FROM AUTHOR]

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An overview is given of magnetic resonance (MR) techniques sensitized to diffusion, flow, magnetization transfer effect, and local field inhomogeneities induced by physiological changes, that can be viewed, in the clinical practice, as advanced because of their challenging implementation and interpretation. These techniques are known as diffusion-weighted, perfusion, magnetization transfer, functional MRI and MR spectroscopy. An important issue is that they can provide quantitative estimates of structural and functional characteristics that are below the voxel resolution. This review does not deal with the basic concepts of the MR physics and the description of the available acquisition and postprocessing methods, but hopefully provides an adequate background to readers and hence facilitate the understanding of the following clinical contributions. [ABSTRACT FROM AUTHOR]

We describe the magnetic resonance (MR) imaging characteristics of dysembryoplastic neuroepithelial tumors (DNT) and discuss their differential diagnosis. Proton MR spectroscopy (TE 30 and 136 ms), diffusion-weighted and perfusion images were retrospectively evaluated in 22 patients with pathologically proven DNT (17 male and 5 female, mean age 18.7 years) and 14 control subjects (10 male and 4 female, mean age 16.9 years). The results from the DNT patients and from the control subjects were compared using an independent sample t-test and the degree of correlation was tested by Pearson’s correlation. All DNTs were solitary and in a supratentorial cortical or subcortical location (ten temporal, eight frontal and four parietal). They had low-signal on T1-weighted images and high-signal on T2-weighted images without a prominent mass effect. Additionally a cystic appearance (six patients, 27.3%), cortical dysplasia (six patients, 27.3%) and contrast enhancement (four patients, 18.2%) were also noted. No significant differences were detected in NAA/Cho, NAA/Cr, NAA/Cho+Cr or Cho/Cr ratios between DNT and normal brain. DNTs had a significantly higher mI/Cr ratio and apparent diffusion coefficient (ADC) values and lower cerebral blood values than normal parenchyma ( P < 0.001). ADC had the highest correlation with the diagnosis of DNT ( r = 0.996) followed by relative cerebral blood volume (rCBV) ( r = −0.883) and mI/Cr ratio ( r = 0.663). Proton MR spectroscopy, diffusion-weighted and perfusion imaging characteristics of DNTs provide additional information to their MR imaging findings. The MR spectrum showing a slight increase in mI/Cr ratio, and higher ADC and lower rCBV values than normal parenchyma help to differentiate DNTs from other cortical tumors, which had higher rCBV and lower ADC values than DNTs. [ABSTRACT FROM AUTHOR]

To evaluate the clinical application of proton magnetic resonance spectroscopy (1HMRS) in patients with radiotherapy treated intracranial tumors. Forty patients with intracranial tumors underwent multivoxel 1HMRS examination before and after radiotherapy. The concentrations of N-acetyl aspartate (NAA), choline (Cho) and creatine (Cr) were obtained both in the tumors and the contralateral normal brain regions. The ratios of NAA/Cr, Cho/Cr and Cho/NAA were calculated at the same time and follow-up one year. (1) After radiotherapy, tumors inhibited by radiation had decreased Cho, NAA and Cr on proton MRS. Some cases showed necrotic wave. (2) During the one year follow-up, local tumor recurred in 8 cases and their Cho and Cho/NAA increased high again. Other cases without recurrence, 1HMRS showed no change. Multivoxel proton MR spectroscopy is available for study of tumor metabolites after radiotherapy and it is a valuable method in the evaluation of radiotherapy treated tumors. [ABSTRACT FROM AUTHOR]

Benign and malignant neoplasms as well as metastatic lymph nodes of 39 patients were examined using localized single voxel magnetic resonance spectroscopy (MRS) [repetition time (TR) 1500, echo time (TE) 135) at 1.5 T. New techniques with simultaneous correction of motion artefacts during the acquisition, three-dimensional saturation pulses, respiratory triggering and smaller volume of interest (VOI) size, were applied. Ratios of peak areas under the choline (Cho) and creatine (Cr) resonances were estimated in all cases and compared with those from samples of normal tissue. Ninety one spectra were acquired in 39 patients, 63 of which were suitable for further evaluation. The smallest VOI was 0.40 cm(3). The Cho/Cr ratios in all malignant neoplasms (mean: 5.2, range: 1.7-17.8) were significantly elevated relative to those in the normal muscle structures (mean: 0.9, range: 0.2-1.4), while those in the benign neoplasms were elevated (mean: 24.4, range: 1.4-59.7) with respect to those in the malignant ones. The average Cho/Cr ratio in the metastatic lymph nodes was significantly higher (mean: 4.8, range: 3.3-5.6) than that for benign lymphoid hyperplasia (mean: 2.2, range: 1.0-3.0). MRS measurements were able to differentiate recurrent disease from post-therapeutic tissue changes in 11 out of 13 patients. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the diffusion MRI and proton MR spectroscopy findings in a rare disorder, Rasmussen's encephalitis. Diffusion MRI studies of 3 cases of Rasmussen's encephalitis were performed using the echo-planar trace sequence (TR=5700 ms, TE=139.03 ms). The gradient-echo diffusion sequence, PSIF (TR=21.6 ms, TE=5 ms), which is a reverse FISP sequence, and proton MR spectroscopy (TR=1500 ms, TE=40 ms) were applied in two patients. The trace sequence revealed high apparent diffusion coefficient values at the diseased regions (1.21+/-0.13 x 10(-3) mm2/s), compared with normal parenchymal values in 12 control cases (0.84+/-0.09 x 10(-3) mm2/s), indicating increased motion of water molecules (disintegration of the tissue) in these regions. The PSIF sequence revealed pixel value differences between the two hemispheres. Proton MR spectroscopy revealed decreased N-acetyl aspartate peaks, compared with five control cases. [ABSTRACT FROM AUTHOR]

A patient with suprasellar and brain stem involvement in Erdheim Chester disease (ECD) underwent magnetic resonance (MR) imaging and proton MR spectroscopy (1H MRS) of the ventral pons before and 1, 4 and 18 months after external whole-brain (24 Gy) radiotherapy. By revealing a decrease of the N-acetyl-aspartate/choline ratio in the pons, 1H MR spectroscopy anticipated lesions growth on MR imaging. In line with the results in four patients reported in the literature, our observation indicates that external radiation therapy is not effective for intracranial involvement in ECD. [ABSTRACT FROM AUTHOR]

Magnetic resonance spectroscopy (MRS) has attracted much attention in recent years and has become an important tool to study in vivo particular biochemical aspects of brain disorders. Since the proton is the most sensitive stable nucleus for MRS, and since almost all metabolites contain hydrogen atoms, investigation by in vivo 1H MRS provides chemical information on tissue metabolites, thus enabling a non-invasive assessment of changes in brain metabolism underlying several brain diseases. In this review a brief description of the basic principles of MRS is given. Moreover, we provide some explanations on the techniques and technical problems related to the use of 1H MRS in vivo including water suppression, localization, editing, quantitation and interpretation of 1H spectra. Finally, we discuss the more recent advancement in three major areas of neurological diseases: brain tumors, multiple sclerosis, and inborn errors of metabolism. [ABSTRACT FROM AUTHOR]