10/20, 10/10, and 10/5 systems revisited: their validity as relative head-surface-based positioning systems

With the advent of multi-channel EEG hardware systems and the concurrent development of topographic and tomographic signal source localization methods, the international 10/20 system, a standard system for electrode positioning with 21 electrodes, was extended to higher density electrode settings such as 10/10 and 10/5 systems, allowing more than 300 electrode positions. However, their effectiveness as relative head-surface-based positioning systems has not been examined. We previously developed a virtual 10/20 measurement algorithm that can analyze any structural MR head and brain image. Extending this method to the virtual 10/10 and 10/5 measurement algorithms, we analyzed the MR images of 17 healthy subjects. The acquired scalp positions of the 10/10 and 10/5 systems were normalized to the Montreal Neurological Institute (MNI) stereotactic coordinates and their spatial variability was assessed. We described and examined the effects of spatial variability due to the selection of positioning systems and landmark placement strategies. As long as a detailed rule for a particular system was provided, it yielded precise landmark positions on the scalp. Moreover, we evaluated the effective spatial resolution of 329 scalp landmark positions of the 10/5 system for multi-subject studies. As long as a detailed rule for landmark setting was provided, 241 scalp positions could be set effectively when there was no overlapping of two neighboring positions. Importantly, 10/10 positions could be well separated on a scalp without overlapping. This study presents a referential framework for establishing the effective spatial resolutions of 10/20, 10/10, and 10/5 systems as relative head-surface-based positioning systems.     

Validation of intimate correlation between visceral fat and hepatic steatosis: Quantitative measurement techniques using CT for area of fat and MR for hepatic steatosis

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Prediction of chemotherapeutic response of colorectal liver metastases with dynamic gadolinium-DTPA-enhanced MRI and localized 19F MRS pharmacokinetic studies of 5-fluorouracil

Systemic chemotherapy is effective in only a subset of patients with metastasized colorectal cancer. Therefore, early selection of patients who are most likely to benefit from chemotherapy is desirable. Response to treatment may be determined by the delivery of the drug to the tumor, retention of the drug in the tumor and by the amount of intracellular uptake, metabolic activation and catabolism, as well as other factors. The first aim of this study was to investigate the predictive value of DCE-MRI with the contrast agent Gd-DTPA for tumor response to first-line chemotherapy in patients with liver metastases of colorectal cancer. The second aim was to investigate the predictive value of 5-fluorouracil (FU) uptake, retention and catabolism as measured by localized (19)F MRS for tumor response to FU therapy. Since FU uptake, retention and metabolism may depend on tumor vascularization, the relationship between (19)F MRS and the DCE-MRI parameters k(ep), K(trans) and v(e) was also examined (1). In this study, 37 patients were included. The kinetic parameters of DCE-MRI, k(ep), K(trans) and v(e), before start of treatment did not predict tumor response after 2 months, suggesting that the delivery of chemotherapy by tumor vasculature is not a major factor determining response in first-line treatment. No evident correlations between (19)F MRS parameters and tumor response were found. This suggests that in liver metastases that are not selected on the basis of their tumor diameter, FU uptake and catabolism are not limiting factors for response. The transfer constant K(trans), as measured by DCE-MRI before start of treatment, was negatively correlated with FU half-life in the liver metastases, which suggests that, in metastases with a larger tumor blood flow or permeability surface area product, FU is rapidly washed out from the tumor.     

An automated quantitation of short echo time MRS spectra in an open source software environment: AQSES

This paper describes a new quantitation method called AQSES for short echo time magnetic resonance spectra. This method is embedded in a software package available online from www.esat.kuleuven.be/sista/members/biomed/new/ with a graphical user interface, under an open source license, which means that the source code is freely available and easy to adapt to specific needs of the user. The quantitation problem is mathematically formulated as a separable nonlinear least-squares fitting problem, which is numerically solved using a modified variable-projection procedure. A macromolecular baseline is incorporated into the fit via nonparametric modelling, efficiently implemented using penalized splines. Unwanted components such as residual water are removed with a maximum-phase FIR filter. Constraints on the phases, dampings and frequencies of the metabolites can be imposed. AQSES has been tested on simulated MR spectra with several types of disturbance and on short echo time in vivo proton MR spectra. Results show that AQSES is robust, easy to use and very flexible.     

In vivo magnetic resonance spectroscopy of transgenic mouse models with altered high-energy phosphoryl transfer metabolism

Studies of transgenic mice provide powerful means to investigate the in vivo biological significance of gene products. Mice with an under- or overexpression of enzymes involved in high-energy phosphoryl transfer (approximately P) are particulary attractive for in vivo MR spectroscopy studies as the substrates of these enzymes are metabolites that are visible in MR spectra. This review provides a brief overview of the strategies used for generation and study of genetically altered mice and introduces the reader to some practical aspects of in vivo MRS studies on mice. The major part of the paper reviews results of in vivo MRS studies on transgenic mice with alterations in the expression of enzymes involved in approximately P metabolism, such as creatine kinase, adenylate kinase and guanidinoacetate methyl transferase. The particular metabolic consequences of these enzyme deficiencies in skeletal muscle, brain, heart and liver are addressed. Additionally, the use of approximately P systems as markers of gene expression by MRS, such as after viral transduction of genes, is described. Finally, a compilation of tissue levels of metabolites in skeletal muscle, heart and brain of wild-type and transgenic mice, as determined by in vivo MRS, is given. During the last decade, transgenic MRS studies have contributed significantly to our understanding of the physiological role of phosphotransfer enzymes, and to the view that these enzymes together build a much larger metabolic energy network that is highly versatile and can dynamically adapt to intrinsic genotoxic and extrinsic physiological challenges.     

H–MRS 半定量技术在新生儿高胆红素血症 脑损伤中的应用

〔摘 要〕 目的：评估氢质子磁共振波谱（1 H–MRS）半定量技术运用于高胆红素血症新生儿脑损伤评估中的诊断作用。 方法：抽选 2018 年 1 月至 2020 年 6 月郴州市第一人民医院诊断的 200 例高胆红素血症新生儿纳入本研究,开展磁共振成 像（MRI）平扫检测、1 H–MRS 半定量技术检测,研究苍白球有改变及无改变新生儿临床各项指标测定结果、1 H–MRS 诊断 指标结果,统计各项检测方式对新生儿是否存在脑损伤的诊断作用。结果：苍白球有改变新生儿总胆红素水平与苍白球无 改变新生儿比较,差异无统计学意义（P ＞ 0.05）;苍白球有改变新生儿总胆红素与白蛋白比值、S100B 蛋白水平高于苍 白球无改变新生儿,且新生儿行为神经测定表（NBNA）评分低于苍白球无改变新生儿,差异具有统计学意义（P ＜ 0.05）。 苍白球有改变新生儿胆碱（Cho）/ 肌酸（Cr）、Cr/N– 乙酰天冬氨酸（NAA）高于苍白球无改变新生儿,NAA/Cr 低于苍白 球无改变新生儿,差异均具有统计学意义（P ＜ 0.05）。以临床诊断结果为金标准,MRI、NBNA 评分、1H–MRS、S100B 蛋白水平诊断新生儿存在脑损伤占比分别与临床诊断比较,差异均无统计学意义（P ＞ 0.05）。结论：为高胆红素血症新 生儿采取 1 H–MRS 半定量技术和 MRI 技术有助于较早评估其脑损伤情况。     

Design of non-invasive glucose meter using near-infrared technique

Diabetics need to keep track of their blood glucose level and measure it regularly to determine their insulin dose intake and to ensure that glucose level is always within the normal range. In this article, a system that enables the measurement of blood glucose level non-invasively is designed. This article uses a near infra-red (NIR) transmittance spectroscopy, without drawing blood, puncturing the skin, or causing pain. It involves a light source and light detector circuits positioned on a certain region of the body. The attenuated received infra-red signal by the detector is a measure of the blood glucose level of that region. Data are collected from the receiving circuit and sent to a microcontroller using CoolTerm application, then exporting it to Excel Sheet, in which mean values and graphs are obtained. The performance of the circuit with and without Filtering is examined. A downward pattern was noticed, as the glucose concentration in the solution increased, the voltage output decreased, meaning that a less intensity light was detected by the receiving circuit. An improvement in the accuracy of measurements by 17% was achieved, when a notch filter is implemented to cut the voltage components corresponding to the power line noisy signals.     

重复经颅磁刺激对脑出血家兔血肿周围组织中化合物含量的影响

目的观察重复经颅磁刺激（rTMS）对脑出血家兔血肿周围组织化合物含量的影响，并探讨其治疗机制。方法家兔36只，随机分为治疗组、模型组和对照组。治疗组和非治疗组采用兔自体血注射制作脑出血模型，对照组注射生理盐水。治疗组家兔于造模后12h开始实施rTMS，每日3次；模型组和对照组不进行rTMS。分别于造模后12h、3d、1周和2周，应用^1H-磁共振波谱（^1H-MRS）检测出血灶周围脑组织N-乙酰天门冬氨酸（NAA）、总肌酸（Cr）和胆碱复合物（Cho）等化合物的含量。结果与对照组比较，模型组和治疗组脑出血灶周组织内NAA和Cr含量减少，NAA／Cr降低，Cho含量增加，Cho／Cr增高（均P〈0．01）；与模型组比较，治疗组NAA、Cr含量增加，NAA／Cr增高，Cho含量减少，Cho／Cr降低（均P〈0．01）。结论rTMS可通过促进血肿周围神经元的修复，影响脑组织中化合物含量，发挥神经保护性治疗作用。