Application of a 3D volume 19FMR imaging protocol for mapping oxygen tension (pO2) in perfluorocarbons at low field

A limited flip angle gradient-echo 3D volume acquisition imaging protocol for mapping partial pressure of oxygen (pO₂) in perfluorocarbon compounds (PFCs) at low field (0.14 T) is presented. The pO₂ measurement method is based on the paramagnetic effect of dissolved molecular oxygen (O₂) which reduces the PFC ¹⁹F T_1? Specific objectives related to imaging of PFCs through use of the protocol include improved image signal-to-noise characteristics and elimination of ¹⁹F chemical shift artifacts. A parametric Wiener deconvolution filtering algorithm is used for suppression of ¹⁹F chemical shift artifacts. Application of the protocol is illustrated in a series of calculated pO₂ maps of a gas equilibrated, multi-chamber phantom containing perfluorotributylamine (FC-43). The utility of the protocol is demonstrated in vivo through images of a commercially available perfluorocarbon based blood substitute emulsion containing FC-43 sequestered in the liver and spleen of a rat.     

通过MR扩散张量成像了解与年龄相关的豆状核变化

目的探讨MR扩散张量成像（DTI）观察豆状核年龄相关性变化的价值与意义。方法69名健康志愿者纳入本研究。入组对象按年龄分为3组：≤30岁（I）组，22例；31～50岁（Ⅱ）组，24例；〉50岁（Ⅲ）组，23例。利用DTI分别测量受试者大脑左右两侧壳核、苍白球的表观扩散系数（ADC）值、部分各向异性（FA）值及扩散张量特征值λ1、λ2、λ3。分析不同年龄组间ADC、FA、λ1、λ2、λ3值的差异及与年龄的相关性。结果I、Ⅱ、Ⅲ组的壳核ADC值分别为：（6．68±0．40）×10^-4、（6．47±0．36）×10^-4、（6．44±0．34）×10^-4mm^2／s，苍白球ADC值分别为：（6．13±0．50）×10^-4、（6．05±0．33）×10^-4、（6．05±0．52）×10$-4mm^2／s。I、Ⅱ、Ⅲ组的壳核FA值分别为：0．20±0．03、0．23±0．03、0．25±0．03，苍白球FA值分别为：0.35±0．03、0．36±0．03、0．37±0．04。各年龄组内壳核ADC值大于苍白球，而FA值小于苍白球。壳核FA值的组问差异有统计学意义（F=10．082，P=0.000），壳核I、Ⅱ、Ⅲ组入，值分别为（5．35±0．45）×10^-4、（5．04±0．46）×10^-4、（4．90±0．44）×10^-4mm^2／s，差异亦有统计学意义（F=5．675，P=0．005）；壳核FA值与年龄呈正相关（r=0．555，P〈0．01），λ3值与年龄呈负相关（r=-0.440，P〈0．01）。结论壳核FA值随年龄的增长而上升，λ3值随年龄的增长而下降。     

Spontaneous regression of optic pathways gliomas in three patients with neurofibromatosis type I and critical review of the literature

Case reports The authors report their experience about three children (two girls, one boy; average age 1.6 years) with a spontaneous regression of optic gliomas. All of them had a previous diagnosis of neurofibromatosis type 1 (NF 1). None of them underwent surgery or biopsy nor received chemotherapy or radiotherapy. The complete regression was documented by MRI scans performed during a mean follow-up of 6.3 years.Literature review Moreover, the authors analyze the features of the 16 cases previously reported in English literature of spontaneously regressed optic gliomas with an overview of the different therapeutic strategies. The knowledge that this kind of tumor, particularly in young patients, may regress is important in the decision of the best therapeutic approach.     

Application of an immunosensor for the detection of the β-lactam antibiotic, cephalexin

Public concern surrounding antibiotic contamination in food and food products has made it imperative to develop analytical methods for their detection. Polyclonal antibodies were used in the development of a surface plasmon resonance (SPR)-based inhibition immunoassay for cephalexin. A conjugate consisting of cephalexin-bovine serum albumin (BSA) was immobilized on the dextran gel surface of the sensor chip. Binding/regeneration studies of antibody to immobilized cephalexin were studied and dissociation of the antibody from the immobilized cephalexin was easily achieved with 10 mmol l^-1 NaOH. Forty surface regeneration cycles were carried out and found to be reproducible with only a 7.4% decrease in binding over this number of regenerations. Model inhibition immunoassays for cephalexin were developed in PBS and spiked milk samples with detection ranges of 4.88 to 2,500 ng ml^-1 and 244 to 3,906 pg ml^-1, respectively.     

质子磁共振波谱在胶质瘤诊断中的应用

目的探讨质子磁共振波谱（^1Hmagnetic resonance spectroscopy，^1HMRS）在胶质瘤诊断及分级中的应用。方法回顾分析我院2003年3月～2005年9月质子磁共振波谱检查并经病理证实的36例胶质瘤的临床资料，根据胶质瘤恶性程度不同分为A、B2组，其中A组为低恶性组（包括星形细胞瘤Ⅰ级和Ⅱ级、室管膜瘤、少突胶质细胞瘤等）21例，B组为高恶性组（包括星形细胞瘤Ⅲ级和Ⅳ级、多形性胶质母细胞瘤、间变型室管膜瘤、髓母细胞瘤）15例。观察氮乙酰门冬氨酸（Nacetylaspartate，NAA）、胆碱（choline，Cho）、肌酸（creatine，Cr）、肌醇（Ins）的共振峰及比值。大脑对侧对应正常脑组织的结果作内对照组。结果2组胶质瘤均表现为异常的。HMRS，与大脑对侧对应正常脑组织相比，A、B2组表现为NAA／Cr含量显著下降，Cho／Cr含量显著增高（P均〈0．05），cr总量变化不大，且无规律性（P〉0．05），Ins含量表现为轻度下降（P〉0．05）。A组NAA／Cr和NAA／Cho均显著高于B组（t=4．235，P=0．011；t=2．832，P=0．031），A组Cho／Cr显著低于B组（t=-2．323，P=0．042）。结论。HMRs可提高对胶质瘤诊断和分级的准确性。     

Hip Arthroscopy: Surgical Indications

Successful outcomes of hip arthroscopy are most clearly dependent on selecting appropriate patients. The indications are numerous and continue to evolve. These indications are summarized in this report. The anatomic architecture of the hip region imposes unique challenges to performing this procedure. As a surgeon’s experience evolves, so will his or her indications for this operation. It is imperative to be knowledgeable about the technique, to exercise care with the procedure, and to be certain that it is being performed for proper reasons.     

项目记忆和源记忆的功能磁共振成像研究

目的探讨项目记忆和源记忆的神经基础及其是否存在性别差异。方法健康男女各8名，实验材料为504个高频双汉字词，项目记忆和源记忆实验任务，Block设计，GE1．5T采集功能磁共振成像（mRI）数据，用SPM99分析，得到男女脑功能激活图（P〈0．002，体素块〉20）。结果在P〈0．002，体素块〉20时，女性项目记忆激活双前额叶背外侧BA6（激活数目左右侧分别为62和11个），源记忆较多激活左前额叶背外侧BA6／46（激活数目为59个）；男性项目记忆激活右前额叶背外侧BA6／46（激活数目为64个），源记忆激活双前额叶背外侧BA6（左右侧分别为9和40个）。结论项目记忆更多激活右侧前额叶背外侧，而源记忆更多激活左侧前额叶背外侧。女性较多地引起左前额叶背外侧激活；而男性较多地引起右前额叶背外侧激活。     

Solitary Small Hepatic Angiosarcoma: Initial and Follow-up Imaging Findings

We report an uncommon case of solitary, small hepatic angiosarcoma that was initially considered as a hemangioma. We present the imaging findings, with an emphasis on the initial and follow-up CT and MR findings, as well as report on the more suggestive findings of angiosarcoma than those of a hemangioma.