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1.
B C Goss K P McGee E C Ehman A Manduca R L Ehman 《Magnetic resonance in medicine》2006,56(5):1060-1066
Magnetic resonance elastography (MRE) is a phase-contrast technique that can spatially map shear stiffness within tissue-like materials. To date, however, MRE of the lung has been too technically challenging-primarily because of signal-to-noise ratio (SNR) limitations and phase instability. We describe an approach in which shear wave propagation is not encoded into the phase of the MR signal of a material, but rather from the signal arising from a polarized noble gas encapsulated within. To determine the feasibility of the approach, three experiments were performed. First, to establish whether shear wave propagation within lung parenchyma can be visualized with phase-contrast MR techniques, MRE was performed on excised porcine lungs inflated with room air. Second, a phantom consisting of open-cell foam filled with thermally polarized (3)He gas was imaged with MRE to determine whether shear wave propagation can be encoded by the gas. Third, preliminary evidence of the feasibility of MRE in vivo was obtained by using a longitudinal driver on the chest of a normal volunteer to generate shear waves in the lung. The results suggest that MRE in combination with hyperpolarized noble gases is potentially useful for noninvasively assessing the regional elastic properties of lung parenchyma, and merits further investigation. 相似文献
2.
Yang-Sheng Tzeng Eric Hoffman Janice Cook-Granroth Rie Maurer Niral Shah Joey Mansour Juerg Tschirren Mitchell Albert 《Magnetic resonance in medicine》2007,58(3):636-642
An anthropomorphic airway tree phantom was imaged with both hyperpolarized (HP) 3He MRI using a dynamic projection scan and computed tomography (CT). Airway diameter measurements from the HP 3He MR images obtained using a newly developed model-based algorithm were compared against their corresponding CT values quantified with a well-established method. Of the 45 airway segments that could be evaluated with CT, only 14 airway segments (31%) could be evaluated using HP 3He MRI. No airway segments smaller than approximately 4 mm in diameter and distal to the fourth generation were adequate for analysis in MRI. For the 14 airway segments measured, only two airway segments yielded a non-equivalent comparison between the two imaging modalities, while eight more had inconclusive comparison results, leaving only four airway segments (29%) that satisfied the designed equivalence criteria. Some of the potential problems in airway diameter quantification described in the formulation of the model-based algorithm were observed in this study. These results suggest that dynamic projection HP 3He MRI may have limited utility for measuring airway segment diameters, particularly those of the central airways. 相似文献
3.
Bastiaan Driehuys Julia Walker Jim Pollaro Gary P Cofer Nilesh Mistry David Schwartz G Allan Johnson 《Magnetic resonance in medicine》2007,58(5):893-900
In the study of asthma, a vital role is played by mouse models, because knockout or transgenic methods can be used to alter disease pathways and identify therapeutic targets that affect lung function. Assessment of lung function in rodents by available methods is insensitive because these techniques lack regional specificity. A more sensitive method for evaluating lung function in human asthma patients uses hyperpolarized (HP) (3)He MRI before and after bronchoconstriction induced by methacholine (MCh). We now report the ability to perform such (3)He imaging of MCh response in mice, where voxels must be approximately 3000 times smaller than in humans and (3)He diffusion becomes an impediment to resolving the airways. We show three-dimensional (3D) images that reveal airway structure down to the fifth branching and visualize ventilation at a resolution of 125 x 125 x 1000 microm(3). Images of ovalbumin (OVA)-sensitized mice acquired after MCh show both airway closure and ventilation loss. To also observe the MCh response in naive mice, we developed a non-slice-selective 2D protocol with 187 x 187 microm(2) resolution that was fast enough to record the MCh response and recovery with 12-s temporal resolution. The extension of (3)He MRI to mouse models should make it a valuable translational tool in asthma research. 相似文献
4.
本文通过对小鼠急性毒性实验,抗炎实验,对胸腺脾脏的影响及对豚鼠在体、离体气管平滑肌作用实验,观察了郃郎喘必消冲剂的药理学效应。结果表明,该制剂无明显毒性,最大耐受量为1000g/kg/d。它有明显的对抗二甲苯致小鼠耳炎及延长组胺诱发哮喘发作潜伏期的作用,对豚鼠离体气管平滑肌无松驰作用,对小鼠胸腺和脾脏有使其重量减小的趋势,但与对照组比较无显著性差异。 相似文献
5.
测量了兔动脉和静脉对 He-Ne激光的反射和透射传输特性。实验采用两积分球系统及波长为632.8nm的He-Ne激光器,并根据测量数据及采用 Kubelka-Munk模型分析和计算了兔动脉和静脉组织对该长激光的吸收系数、散射系数及总的光强I(x)及前向散射通量i(x)和后向散射通量j(x)随厚度的变化情况。结果表明,兔动脉和静脉的漫反射率和透射率有明显差别,而且,动脉对激光的吸收系数明显较静脉的要小,而动脉对激光的散射系数却明显较静脉的要大,在动脉和静脉组织中总的光强I(x)及前向散射通量i(x)和后向散射通量j(x)随组织厚度的变化情况也有明显的区别。 相似文献
6.
He-Ne激光重复照射抑制培养增生性瘢痕成纤维细胞胶原合成的实验研究 总被引:3,自引:0,他引:3
目的 探讨He-Ne激光重复照射对培养增生性瘢痕成纤维细胞胶原合成的抑制作用。方法 以不同功率密度(10、50、100和150mW/cm^2)He-Ne激光照射培养增生性瘢痕成纤维细胞30min,1/d,连续照射3d,在3d重复照射后24h用^3H-脯氨酸掺入法和斑点杂交法分别检测成纤维细胞胶原合成和Ⅰ型前胶原基因表达。结果 培养增生性瘢痕成纤维细胞的胶原合成、Ⅰ型前胶原基因表达水平在10、50m 相似文献
7.
徐倍倍 《新疆医科大学学报》1999,22(4):285-287
目的:观察中药配合低能量氦-氖激光血管内照射为主治疗缺血性中风疗效。方法:治疗组:用中药配合低量氦-氖激光血管内照射为主治疗缺血性中风69例;对照组:用降纤酶、尼莫通治疗缺血性中风42 例。结果:治疗组基本痊愈48 例,显效8例,有效7例,无效5 例,恶化1 例,有效率为91.30% 。对照组基本痊愈20例,显效1例,有效9 例,无效11 例,恶化1例,有效率为71.43% 。经χ2 检验,χ2= 7.6,Ρ< 0.01,有显著差异。结论:治疗组中药配合低能量氦-氖激光血管内照射为主治疗缺血性中风综合疗效明显优于对照组用降纤酶和尼莫通治疗缺血性中风 相似文献
8.
9.
柴桂合剂治疗儿童反复呼吸道感染的临床及实验研究 总被引:2,自引:0,他引:2
为研究柴桂合剂治疗儿童反复上呼吸道感染(RRTI)疗效及其机理,检测了23例RRTI患儿柴桂合剂治疗前后免疫功能状况,并与正常对照组比较,结果表明柴桂合剂治疗RRTI临床总有效率95.6%,改善免疫功能状态可能是柴桂合剂治疗RRTI的机理之一。 相似文献
10.
强直性脊柱炎是脊柱关节炎常见的临床类型,好发于青年男性,以中轴关节受累为主,可伴发关节外表现,严重者可发生脊柱畸形和关节强直,是一种慢性炎症性疾病。何老临证潜心研究,注重强直性脊柱炎病变的核心,从临床常见的证型着手,攻克难治之疾,何老认为该病根源在于肾虚,肾虚累及肝脾,脾胃不足则后天之气血精微无以生化,筋脉骨骼失去滋养。肝不足则血虚,继而筋脉失养,发生该病。 相似文献