UNASSIGNED: We aimed to investigate whether combined phosphorous (31P) magnetic resonance spectroscopic imaging (MRSI) and quantitative T 2 \' mapping are able to detect alterations of the cerebral oxygen extraction fraction (OEF) and intracellular pH (pHi) as markers the of cellular energy metabolism in cerebral small vessel disease (SVD).
UNASSIGNED: 32 patients with SVD and 17 age-matched healthy control subjects were examined with 3-dimensional 31P MRSI and oxygenation-sensitive quantitative T 2 \' mapping (1/ T 2 \'  = 1/T2* - 1/T2) at 3 Tesla (T). PHi was measured within the white matter hyperintensities (WMH) in SVD patients. Quantitative T 2 \' values were averaged across the entire white matter (WM). Furthermore, T 2 \' values were extracted from normal-appearing WM (NAWM) and the WMH and compared between patients and controls.
UNASSIGNED: Quantitative T 2 \' values were significantly increased across the entire WM and in the NAWM in patients compared to control subjects (149.51 ± 16.94 vs. 138.19 ± 12.66 ms and 147.45 ± 18.14 vs. 137.99 ± 12.19 ms, p < 0.05). WM T 2 \' values correlated significantly with the WMH load (ρ=0.441, p = 0.006). Increased T 2 \' was significantly associated with more alkaline pHi (ρ=0.299, p < 0.05). Both T 2 \' and pHi were significantly positively correlated with vascular pulsatility in the distal carotid arteries (ρ=0.596, p = 0.001 and ρ=0.452, p = 0.016).
UNASSIGNED: This exploratory study found evidence of impaired cerebral OEF in SVD, which is associated with intracellular alkalosis as an adaptive mechanism. The employed techniques provide new insights into the pathophysiology of SVD with regard to disease-related consequences on the cellular metabolic state.

暂无摘要。

We report the case of a 19-month-old girl with late-onset ornithine transcarbamylase (OTC) deficiency initially referred to gastroenterology for intermittent vomiting lasting a year and abnormal liver enzymes (AST 730 U/L [reference range 26-55 U/L]; ALT 1213 U/L [reference range 11-30 U/L]) without hepatomegaly. While the patient was hospitalized for liver biopsy, intermittent tremors of the upper extremities with varying severity were noted. The patient was presumed to have hyperammonemia secondary to acute liver failure and was discharged after 5 days; follow-up monitoring led to readmission 7 days later. A brain MRI showed nonspecific bilateral pericallosal and bifrontal white matter FLAIR hyperintensities. These findings raised suspicion for a metabolic disease and prompted a genetics consultation. After inconclusive biochemical testing and worsening clinical status, rapid whole genome sequencing results were obtained identifying a novel, de novo, likely pathogenic, variant c.608C > T (p.Ser203Phe) in the OTC gene. The patient was promptly started on an oral nitrogen scavenger, citrulline supplementation, and protein restriction. Ammonia and glutamine levels normalized within 1 month of treatment and have stayed within the goal ranges with continued tailoring of treatment. Her parents noted resolution of vomiting and improved mood stability. Liver enzymes normalized after 2 months of treatment. The tremor, identified as asterixis, improved and a repeat brain MRI 3 months after the initial imaging showed near-complete resolution of previous white matter hyperintensities.

X-linked adrenoleukodystrophy is a rare inherited peroxisomal disorder that occurs due to a genetic mutation. This mutation impairs normal transport of very long-chain fatty acids (VLCFAs) into peroxisomes, hence impeding VLCFA breakdown leading to its accumulation in plasma and tissues of the body. Due to its X-linked inheritance, it classically affects young males with most cases diagnosed during childhood. There are characteristic MRI findings in brain which can aid in diagnosis of X-ALD. We hereby present a case of a 10-year-old boy who presented with neurological and behavioral deterioration with MRI findings suggestive of X-ALD. MRI not only aids in diagnosis of X-ALD but can also identify the pattern of brain involvement which serves an important role in prognosis and outcome of the disease.

Rasmussen\'s encephalitis (RE) is a relatively rare chronic inflammatory neurological disease that usually only affects one hemisphere of the brain. It primarily affects children under the age of 10, although it can also affect teens and adults, causing drug-resistant seizures, progressive hemiparesis, and dementia. RE presents as a challenging diagnosis with MRI as the cornerstone of the evaluation and nuclear imaging as a complementary tool. We\'d like to present a case of a 12-year-old girl who was diagnosed with RE after an MRI. In this study, we examine the diagnostic criteria, differential diagnoses, and issues that underpin the diagnostic challenge in great detail.

UNASSIGNED: Ultrasound of the liver is not good to pick up mild steatosis. Controlled attenuation parameter (CAP) evaluated in transient elastography (FibroScan) is widely available in India. However, data regarding the diagnostic accuracy and optimal cut-off values of CAP for diagnosing hepatic steatosis are scarce in Indian population. MRI-PDFF is an accurate technique for quantifying hepatic steatosis. Thus, this study examined the diagnostic accuracy and optimal cut-off values of CAP for diagnosing steatosis with MRI-PDFF as reference standard.
UNASSIGNED: A total of 137 adults underwent CAP and MRI-PDFF measurements prospectively. A subset of participants (n = 23) underwent liver biopsy as part of liver transplantation evaluation. The optimal cut-off values, area under the receiver operating characteristic (AUROC) curves, sensitivity, and specificity for CAP in detecting MRI-PDFF ≥5% and ≥10% were assessed.
UNASSIGNED: The mean age and body mass index (BMI) were 44.2 ±10.4 years and 28.3 ±3.9 kg/m2, respectively. The mean hepatic steatosis was 13.0 ±7.7% by MRI-PDFF and 303 ±54 dB/m by CAP. The AUROC of CAP for detecting hepatic steatosis (MRI-PDFF ≥5%) was 0.93 (95% CI, 0.88-0.98) at the cut-off of 262 dB/m, and of MRI-PDFF ≥10% was 0.89 (95% CI, 0.84-0.94) at the cut-off of 295 dB/m. The CAP of 262 dB/m had 90% sensitivity and 91% specificity for detecting MRI-PDFF ≥5%, while the CAP of 295 dB/m had 86% sensitivity and 77% specificity for detecting MRI-PDFF ≥10%.
UNASSIGNED: The optimal cut-off of CAP for the presence of liver steatosis (MRI-PDFF ≥5%) was 262 dB/m in Indian individuals. This CAP cut-off was associated with good sensitivity and specificity to pick up mild steatosis.

UNASSIGNED: Acute-on-chronic liver failure (ACLF) is associated with high short-term mortality. There is a paucity of data about the spectrum of neuroimaging abnormalities in the brain in ACLF patients. The present study was aimed to study the prevalence of cerebral edema and other parenchymal changes in MR imaging of the brain in patients with ACLF.
UNASSIGNED: In this prospective observational study, MR imaging was done in patients with ACLF (n = 41), and findings were compared with age and sex-matched patients with acute decompensation (AD) (n = 13) and those with cirrhosis but without any decompensation at recruitment (n = 21).
UNASSIGNED: Forty-one patients with ACLF (24.4% Grade 1 and Grade 2, 51.2% Grade 3) with 14 (34.1%) having cerebral failure were included in the study. T2-weighted (T2W) diffuse white matter hyperintensities (WMHs) and focal WMHs were seen in 17 (41.4%) and 7 (17%) patients, respectively. T1W basal ganglia hyperintensities in 20 (48.7%), cerebral microbleeds (CMBs) in 6 (14.6%), and 2 (4.8%) patients had cerebral edema. In patients with AD, T2W diffuse WMHs were seen in 3 (23%), T2W focal WMHs in 3 (23%) patients. None of the patients with AD had cerebral edema or CMBs. In compensated cirrhosis patients, T2W diffuse WMHs were present in 7 (33.3%), T2W focal WMHs in 5 (23.8%), while 3 (14.2%) patients had CMBs. T1 weighted hyperintensities in basal ganglia were more common in AD [9 (69.2%)] and compensated cirrhosis [15 (71.4%)] as compared to ACLF patients [20 (48.7%)], P = 0.174. The survival time of 30 and 90 days for patients with diffuse T2W WMHs was significantly lesser than patients without T2W WMHs (P = 0.007).
UNASSIGNED: Cerebral edema is uncommon in ACLF patients, and T2-weighted diffuse white matter hyperintensities may be associated with worse outcomes. However, due to the limited scope of the present study, the same needs to be explored further in larger cohorts.

UNASSIGNED: Chondrosarcoma is a common form of malignant bone tumor with limited treatment options. Approximately half of chondrosarcomas harbor gain-of-function mutations in isocitrate dehydrogenase (IDH), and mutant IDH produces 2-hydroxyglutarate (2-HG), which is an oncometabolite that contributes to malignant transformation. Therefore, inhibiting 2-HG production is a novel and promising treatment for advanced chondrosarcoma. 2-HG is also expected to be a useful biomarker for the diagnosis and treatment of IDH-mutant tumors. However, few studies have confirmed this using chondrosarcoma clinical specimens. Non-invasive monitoring of 2-HG levels is useful to infer that mutant IDH inhibitors reach therapeutic targets and to confirm their therapeutic efficacy in clinical practice.
UNASSIGNED: To evaluate the clinical utility of 2-HG as a surrogate biomarker for diagnosis and therapeutic efficacy, we measured intra-tumor and serum levels of 2-HG using frozen tissues and peripheral blood from patients with chondrosarcoma. We also developed a non-invasive method to detect intra-tumor 2-HG signals in vivo using magnetic resonance spectroscopy (MRS).
UNASSIGNED: Both intratumoral and serum 2-HG levels were significantly elevated in IDH-mutant tumors, and these levels correlated with decreased survival. Furthermore, we detected intratumoral 2-HG peaks using MR spectroscopy in a xenograft model of IDH-mutant chondrosarcoma, and observed that 2-HG peak signals disappeared after administering an inhibitor of mutant IDH1.
UNASSIGNED: Our findings suggest that both intratumoral and serum 2-HG levels represent potentially useful biomarkers for IDH-mutant tumors and that the 2-HG signal in MR spectra has potential value as a non-invasive biomarker. Taken together, these findings may positively impact the clinical development of mutant IDH inhibitors for the treatment of advanced chondrosarcoma.

Aging is by far the most prominent risk factor for Alzheimer\'s disease (AD), and both aging and AD are associated with apparent metabolic alterations. As developing effective therapeutic interventions to treat AD is clearly in urgent need, the impact of modulating whole-body and intracellular metabolism in preclinical models and in human patients, on disease pathogenesis, have been explored. There is also an increasing awareness of differential risk and potential targeting strategies related to biological sex, microbiome, and circadian regulation. As a major part of intracellular metabolism, mitochondrial bioenergetics, mitochondrial quality-control mechanisms, and mitochondria-linked inflammatory responses have been considered for AD therapeutic interventions. This review summarizes and highlights these efforts.

UNASSIGNED: Nonalcoholic fatty liver disease (NAFLD) is becoming the most common cause of cirrhosis. Although magnetic resonance spectroscopy (MRS) is considered the gold standard, it has a few limitations. The role of diffusion-weighted imaging (DWI), which is a simpler sequence, in the diagnosis and grading of fatty liver is not well studied. The aim of the study was to investigate the value of DWI in the diagnosis and grading of hepatic steatosis in patients with NAFLD.
UNASSIGNED: Fifty-one adults (mean age: 38 years; 28 men, 23 women) with NAFLD, diagnosed clinically and by ultrasonography (USG), were included in the study after obtaining informed consent and approval from the institute ethics committee. USG was performed for grading of hepatic steatosis in all patients, followed by magnetic resonance imaging with DWI and MRS, on a 1.5T scanner. The mean apparent diffusion coefficient (ADC) values and proton density fat fraction (PDFF) were calculated, and MRS was used as the gold standard. The mean ADC values were compared with the PDFF and USG grades.
UNASSIGNED: There was a weak correlation between ADC values and PDFF (r = -0.36; P < 0.05). In addition, there was a weak correlation between the ADC values of the liver and USG grade (r = -0.34; P < 0.05). However, an overall increase in USG grades and PDFF was associated with decrease in the mean ADC value (P < 0.001).
UNASSIGNED: DWI is not accurate in the diagnosis and grading of hepatic steatosis in patients with NAFLD. However, a significant increase in fat deposition in the liver lowers the ADC values.