Metabolite Levels Measured Using Magnetic Resonance Spectroscopy in Pediatric Methotrexate-Induced Leukoencephalopathy.

Background: Methotrexate (MTX)-induced leukoencephalopathy is a significant neurological complication in pediatric acute lymphoblastic leukemia (ALL) treatment. Magnetic resonance spectroscopy (MRS) is a noninvasive method to assess metabolic changes associated with neurotoxicity. This study aimed to evaluate the diagnostic and prognostic value of MRS-derived metabolite levels, particularly N-acetylaspartate and N-acetylaspartylglutamate (tNAA), in MTX-induced leukoencephalopathy.

Magnetic Resonance Water Tracer Imaging Using 17 O-Labeled Water.

Magnetic resonance imaging (MRI) is a crucial imaging technique for visualizing water in living organisms. Besides proton MRI, which is widely available and enables direct visualization of intrinsic water distribution and dynamics in various environments, MR-WTI (MR water tracer imaging) using 17 O-labeled water has been developed, benefiting from the many advancements in MRI software and hardware that have substantially improved the signal-to-noise ratio and made possible faster imaging. This cutting-edge technique allows the generation of novel and valuable images for clinical use.

Intraocular Water Movement Visualization Using H-MRI With Eye Drops of O-17-Labeled Saline: First-in-Human Study.

Background: Visualization of aqueous humor flow in MR contrast images using gadolinium is challenging because of the delayed contrast effects associated with the blood-retinal and blood-aqueous humor barriers. However, oxygen-17 water (H O) might be used as an ocular contrast agent.

Purpose: To observe the distribution of H O in the human eye, and its flow in and out of the anterior chamber, using dynamic T2-weighted MRI.

In vivo Human MR Spectroscopy Using a Clinical Scanner: Development, Applications, and Future Prospects.

MR spectroscopy (MRS) is a unique and useful method for noninvasively evaluating biochemical metabolism in human organs and tissues, but its clinical dissemination has been slow and often limited to specialized institutions or hospitals with experts in MRS technology. The number of 3-T clinical MR scanners is now increasing, representing a major opportunity to promote the use of clinical MRS. In this review, we summarize the theoretical background and basic knowledge required to understand the results obtained with MRS and introduce the general consensus on the clinical utility of proton MRS in routine clinical practice.

Comparison of Predictive Values of Magnetic Resonance Biomarkers Based on Scan Timing in Neonatal Encephalopathy Following Therapeutic Hypothermia.

Objective: To determine the optimal quantitative magnetic resonance (MR) biomarker in neonatal encephalopathy following therapeutic hypothermia based on scan timing.

Study Design: This retrospective study included 98 neonates (35-41 weeks of gestation) with neonatal encephalopathy, who underwent therapeutic hypothermia; diffusion-weighted imaging and proton MR spectroscopy were performed at 24-96 hours (n = 56) and 7-14 days (n = 92) after birth, respectively, to estimate apparent diffusion coefficient (ADC) values, N-acetylaspartate and N-acetylaspartylglutamate (tNAA), lactate, and choline concentrations, and lactate/tNAA, tNAA/choline ratios in the deep gray matter. Adverse outcomes included death or neurodevelopmental impairment at 18-22 months of age.

Altered brain metabolite concentration and delayed neurodevelopment in preterm neonates.

Background: A very-low-birth-weight (VLBW) preterm infants is associated with an increased risk of impaired neurodevelopmental outcomes. In this study, we investigated how neonatal brain metabolite concentrations changed with postmenstrual age and examined the relationship between changes in concentration (slopes) and neurodevelopmental level at 3-4 years.

Methods: We retrospectively examined 108 VLBW preterm infants who had brain single-voxel magnetic resonance spectroscopy at 34-42 weeks' postmenstrual age.

Association between Brain and Plasma Glutamine Levels in Healthy Young Subjects Investigated by MRS and LC/MS.

Both glutamine (Gln) and glutamate (Glu) are known to exist in plasma and brain. However, despite the assumed relationship between brain and plasma, no studies have clarified the association between them. Proton magnetic resonance spectroscopy (MRS) was sequentially performed twice, with a 60-min interval, on 10 males and 10 females using a 3T scanner.

Changes in Brain Metabolite Concentrations after Neonatal Hypoxic-ischemic Encephalopathy.

Purpose To investigate the time-course changes and predictive utility of brain metabolite concentrations in neonatal hypoxic-ischemic encephalopathy (HIE). Materials and Methods Sixty-eight neonates (age, 35-41 gestational weeks) with HIE were admitted to a neonatal intensive care unit between September 2009 and March 2016 and examined by using proton MR spectroscopy at 18-96 hours (n = 25) and 7-14 days (n = 64) after birth (35-43 postmenstrual weeks) to estimate metabolite concentrations in the deep gray matter. Adverse outcome was defined as death or neurodevelopmental impairment at 18-22 months of age.

Serial Magnetic Resonance Imaging and H-Magnetic Resonance Spectroscopy in GABA Transaminase Deficiency: A Case Report.

Gamma-aminobutyric acid transaminase (GABA-T) deficiency is a rare, autosomal recessive disorder characterized by severe psychomotor retardation, early-onset epileptic encephalopathy, intractable seizures, hypotonia, and hyperreflexia. The disease is caused by mutation in the 4-aminobutyrate aminotransferase (ABAT) gene, which encodes an enzyme involved in GABA catabolism. In this chapter, a 10-year follow-up of GABA-T deficiency in a rare case of a long-term survivor patient is discussed.

In vivo estimation of gamma-aminobutyric acid levels in the neonatal brain.

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the brain, and plays a key role in brain development. However, the in vivo levels of brain GABA in early life are unknown. Using edited MRS, in vivo GABA can be detected as GABA+ signal with contamination of macromolecule signals.

Normal lactate concentration range in the neonatal brain.

Objective: Lactate peaks are occasionally observed during in vivo magnetic resonance spectroscopy (MRS) scans of the neonatal brain, even in healthy patients. The purpose of this study was to investigate the normal range of neonatal brain lactate concentration, as a definitive normal range would be clinically valuable.

Methods: Using a clinical 3T scanner (echo/repetition times, 30/5000ms), single-voxel MRS data were obtained from the basal ganglia (BG) and centrum semiovale (CS) in 48 healthy neonates (postconceptional age (PCA), 30-43weeks), nine infants (age, 1-12months old), and 20 children (age, 4-15years).

Neonatal case of classic maple syrup urine disease: usefulness of (1) H-MRS in early diagnosis.

We describe a male neonate with classic maple syrup urine disease (MSUD) in metabolic crisis. On day 7 of life, he was referred to hospital because of coma and metabolic acidosis with maple syrup odor. On day 4 after admission, brain magnetic resonance imaging findings were consistent with encephalopathy due to MSUD.

Neonatal brain metabolite concentrations: an in vivo magnetic resonance spectroscopy study with a clinical MR system at 3 Tesla.

Brain metabolite concentrations change dynamically throughout development, especially during early childhood. The purpose of this study was to investigate the brain metabolite concentrations of neonates (postconceptional age (PCA): 30 to 43 weeks) using single-voxel magnetic resonance spectroscopy (MRS) and to discuss the relationships between the changes in the concentrations of such metabolites and brain development during the neonatal period. A total of 83 neonatal subjects were included using the following criteria: the neonates had to be free of radiological abnormalities, organic illness, and neurological symptoms; the MR spectra had to have signal-to-noise ratios ≥ 4; and the estimated metabolite concentrations had to display Cramér-Rao lower bounds of ≤ 30%.

Transient ischemic attack-like episodes without stroke-like lesions in MELAS.

A stroke-like episode is a core symptom in mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). Proton magnetic resonance spectroscopy (1H-MRS) is useful in the diagnosis of mitochondrial diseases. We report an 8-year-old girl with MELAS, presenting with a seizure and blindness.

Monitoring the brain metabolites of children with acute encephalopathy caused by the H1N1 virus responsible for the 2009 influenza pandemic: a quantitative in vivo 1H MR spectroscopy study.

Background And Purpose: Influenza viral infection, which results in central nervous system dysfunction, is a major cause of acute encephalopathy (AE). The purpose of this study was to investigate the changes in the concentrations of brain metabolites in children with AE using single-voxel magnetic resonance spectroscopy (MRS) and to provide diagnostic information about the relationship between the symptoms of AE and metabolite concentrations.

Materials And Methods: The subjects were 10 children (mean age: 6.

Acute hemicerebellitis in a pediatric patient: a case report of a serial MR spectroscopy study.

The changes in the signals for brain metabolites in the left cerebellum of a 14-year-old boy with acute hemicerebellitis were monitored using proton magnetic resonance spectroscopy (MRS). From the onset of disease treatment to long-term follow-up, MRS data were serially acquired from the left and right cerebella, basal ganglia (BG), and centrum semiovale (CS). Large fluctuations in his MRS signals were observed in the left cerebellum.

Combination of two fat saturation pulses improves detectability of glucose signals in carbon-13 MR spectroscopy.

In order to improve the fat suppression performance of in vivo (13)C-MRS operating at 3.0 Tesla, a phantom model study was conducted using a combination of two fat suppression techniques; a set of pulses for frequency (chemical shift) selective suppression (CHESS), and spatial saturation (SAT). By optimizing the slab thickness for SAT and the irradiation bandwidth for CHESS, the signals of the -(13)CH(3) peak at 49 ppm and the -(13)CH(2)- peak at 26 ppm simulating fat components were suppressed to 5% and 19%, respectively.

A new case of GABA transaminase deficiency facilitated by proton MR spectroscopy.

Background: Deficiency of 4-aminobutyrate aminotransferase (GABA-T) is a rare disorder of GABA catabolism, with only a single sibship reported. We report on a third case, a Japanese female infant with severe psychomotor retardation and recurrent episodic lethargy with intractable seizures, with the diagnosis facilitated by proton magnetic resonance (MR) spectroscopy ((1)H-MRS).

Methods: Neuroimaging was performed at the first episode of lethargy.

A phantom study on component segregation for MR images using ICA.

Rationale And Objectives: A phantom set was devised to evaluate capability of independent component analysis (ICA) as an image filter for magnetic resonance (MR) images to segregate components.

Materials And Methods: Four components (free water [FW], olive oil [OL], 2% and 4% agar gels [2A and 4A, respectively]) were arranged in a phantom set. Seven MR images were obtained with different echo time and repetition time.

A multi-compartmental SE-BOLD interpretation for stimulus-related signal changes in diffusion-weighted functional MRI.

A new interpretation is proposed for stimulus-induced signal changes in diffusion-weighted functional MRI. T(2)-weighted spin-echo echo-planar images were acquired at different diffusion-weightings while visual stimulation was presented to human volunteers. The amplitudes of the positive stimulus-correlated response and post-stimulus undershoot (PSU) in the functional time-courses were found to follow different trends as a function of b-value.

Monitoring of liver glycogen synthesis in diabetic patients using carbon-13 MR spectroscopy.

To investigate the relationship between liver glucose, glycogen, and plasma glucose in diabetic patients, in vivo liver carbon-13 magnetic resonance spectroscopy ((13)C MRS) with a clinical 3.0T MR system was performed. Subjects were healthy male volunteers (n=5) and male type-2 diabetic patients (n=5).

Evaluating glycogen signal contamination in muscle by (13)C MRS of the liver.

To evaluate the contamination of glycogen signal synthesized in skeletal muscle by that in the liver, long-term monitoring of over 7 h of in vivo [1-(13)C] glycogen synthesis/degradation at the right abdomen and left shoulder was achieved using a 3.0-T clinical MR system. (13)C MR spectra without localization were obtained from five healthy volunteers before and after oral administration of 85 g of d-glucose, including 10 g of 99% [1-(13)C] glucose.