Three-dimensional magnetic resonance myocardial motion tracking from a single image plane.

Three-dimensional imaging for the quantification of myocardial motion is a key step in the evaluation of cardiac disease. A tagged magnetic resonance imaging method that automatically tracks myocardial displacement in three dimensions is presented. Unlike other techniques, this method tracks both in-plane and through-plane motion from a single image plane without affecting the duration of image acquisition. A small z-encoding gradient is subsequently added to the refocusing lobe of the slice-selection gradient pulse in a slice following CSPAMM acquisition. An opposite polarity z-encoding gradient is added to the orthogonal tag direction. The additional z-gradients encode the instantaneous through plane position of the slice. The vertical and horizontal tags are used to resolve in-plane motion, while the added z-gradients is used to resolve through-plane motion. Postprocessing automatically decodes the acquired data and tracks the three-dimensional displacement of every material point within the image plane for each cine frame. Experiments include both a phantom and in vivo human validation. These studies demonstrate that the simultaneous extraction of both in-plane and through-plane displacements and pathlines from tagged images is achievable. This capability should open up new avenues for the automatic quantification of cardiac motion and strain for scientific and clinical purposes.     

手法为主综合治疗腰椎间盘突出手术后复发

腰椎间盘突出症所引起的腰腿痛,目前多主张以保守治疗为主,但经手术治疗的也有一定比率。自2000年10月-2005年12月共收治经手术后复发的腰椎间盘突出症19例,临床应用松肌法、分离神经根粘连法、骨盆旋转整脊法、后伸压腰法、纠正脊柱侧弯法为主,结合骨盆牵引中药熏蒸,药物对症治疗为辅,取得了满意的效果。为探究其疗效机制,现总结如下。1临床资料1.1一般资料19例中,男16例,女3例;年龄26~59岁。有劳损、外伤及受凉诱发者12例。发病部位据CT、MRI检查统计:L3,4椎间盘突出1例,L4,5椎间盘突出9例,L5S1椎间盘突出5例,L4,5和L5S1两节段椎间盘…     

头低位模拟失重状态对前庭功能的影响

为研究头低位模拟失重对运动病症状、垂直视动眼震（ＶＯＫＮ）及体液重新分配的影响，在头低位－１０°的模拟失重状态下，采用大视野的垂直视动刺激，观察１８名正常人的运动病症状、ＶＯＫＮ、激素（ＡＶＰ、ＶＩＰ、ＣＯＲＴ、ＡＬＤＯ）的反应特点。结果表明，头低位－１０°状态下的大视野垂直视动刺激可以诱发出明显的运动病症状，头低位－１０°的垂直视动刺激比坐位更容易诱发运动病。坐位状态ＶＯＫＮ慢相速度有明显的方向性不对称，敏感组ＶＯＫＮ方向性不对称有显著差异（Ｐ＜０．０５）。头低位－１０°时ＶＯＫＮ的不对称现象不明显，向下方向运动的ＶＯＫＮ慢相速度显著增加。分析指出，头低位－１０°状态下垂直视动刺激比坐位和秋千刺激的贡献率大。尿中ＣＯＲＴ（皮质醇）在秋千和头低位的垂直视动刺激前后有显著性增加。提示：大视野的垂直视动刺激与头低位－１０°两种刺激的结合可能成为预测空间运动病的方法之一．     

腰椎间盘术后椎间盘炎的诊治

目的：探讨腰椎间盘术后椎间盘炎的病因。早期诊断和治疗问题。方法：分析10例术后腰椎间盘炎的临床表现、血象、血流变化、血和病灶细菌培养、腰椎X线平片、CT、MRI所见在发病后的敏感程度，比较3例非手术与7例经前路腹膜后（2例联合后入路）病灶清除，一期椎间植骨融合本治疗的效果。结果：不同程度的发热、痉挛性腰痛、血流增快是本病的特点。MRI、CF、X线片三者的诊断敏感性存在时间差，分别约为发病后1、3、5周。仅2例血和病灶细菌培养均阳性。前路减压植骨融合术减少全身性抗生素和镇痛剂的使用量，明显缩短病程。结论：ESR、MRI对早期确诊、引导手术价值较高。高热、痉挛性腰痛、血沉增快三者具一持续2周得不到控制，可考虑及早手术。手术疗法近期效果更为确切。     

Binocular afferents to the salamander pretectum mediate rotation sensitivity of cells selective for visual background motions

The majority (85%) of background motion-sensitive pretectal cells in salamanders was found to be binocularly driven. In 70% of the units the binocularity establishes a rotation selectivity with respect to background pattern-movements. This results in a considerable augmentation of the discharge rate when pattern movement is perceived simultaneously in the temporonasal direction by the contralateral eye and nasotemporally by the ipsilateral eye. The response is depressed when the pattern movement is seen in the same direction by both eyes. It is concluded that the rotation-sensitive cells are mainly excited by contralateral retinal afferents selective for temporonasal movements and inhibited by direct or indirect ipsilateral afferents with the same type of direction selectivity.     

Partial k-space reconstruction in single-shot diffusion-weighted echo-planar imaging.

Partial k-space sampling is frequently used in single-shot diffusion-weighted echo-planar imaging (DW-EPI) to reduce the TE and thereby improve the SNR. However, it increases the sensitivity of the technique to bulk rotational motion, which introduces a phase gradient across the tissue that shifts the echo in k-space. If the echo is displaced into the high spatial frequencies, conventional homodyne reconstruction fails, causing intensity oscillations across the image. Zero-padding, on the other hand, compromises the image resolution and may cause truncation artifacts. We present an adaptive version of the homodyne algorithm that detects the location of the echo in k-space and adjusts the center and width of the homodyne filters accordingly. The adaptive algorithm produces artifact-free images when the echo is shifted into the high positive k-space range, and reduces to the standard homodyne algorithm in the absence of bulk motion.     

结缔组织生长因子在椎间盘纤维化和退变中的表达和作用

目的研究疼痛椎间盘组织中结缔组织生长因子（connective tissue growth factor, CTGF）的表达及其在椎间盘纤维化和退变中的作用。方法收集腰椎后路融合过程中切除的43个疼痛的病理椎间盘，来自于28例行腰椎后路椎体间融合手术的严重椎间盘源性下腰痛患者；同时收集16个在MRIT2加权像信号强度明显减弱的无腰痛症状的退变椎间盘，取自于6例腰椎管狭窄症和8例多节段腰椎后路融合的患者（年龄44～75岁，平均53．5岁，男女比例为8：6）和8个正常对照椎间盘，来自于4具新鲜尸体标本（22～39岁，平均28岁）的L。和蛉．椎间盘。均行组织学检查并用免疫组化方法检测CTGF在不同椎间盘组织的表达。结果组织学检查发现，疼痛椎间盘组织显示不同程度的慢性血管化炎症反应。纤维环组织失去正常的胶原纤维板层结构，板层结构断裂、紊乱或相互交叉融合，正常的成纤维细胞被软骨细胞替代。髓核显示明显纤维化、血管浸润或形成炎性肉芽组织，软骨细胞被成纤维细胞所替代。免疫组化染色显示CTGF在疼痛椎间盘大量表达，无腰痛症状的退变椎间盘有少量表达，正常对照椎间盘没有表达。结论疼痛的退变椎间盘在组织学上明显不同于无腰痛症状的退变椎间盘。CTGF在疼痛椎间盘的大量表达可能与椎间盘纤维化和退变过程密切相关。     

Modic改变在腰腿痛病例中的分布及相关因素分析

目的探讨腰椎终板Modic改变在腰腿痛病例中的的临床分布特点，并探讨发生Modic改变的相关因素。方法选择2005年一年内因腰痛或坐骨神经痛行腰椎MR检查和常规X线检查的患者1223例，分析腰椎MRI中终板Modic改变在椎间盘节段、年龄和椎间盘退变分类中的分布特点及其相关因素。结果1223例6115个腰椎椎间盘中，257例（21．0％）320个椎间盘（5．2％）邻近终板发生M0dic改变，其中Ⅰ型48例（3．9％）51个椎间盘（0．8％），Ⅱ型206例（16．8％）266个椎间盘（4．3％）、Ⅲ型3例（0．2％）3个椎间盘（0．05％）。椎间盘节段L5S1 168个、L4-5 95个、L3-4 29个、L2-3 18个、L1-2 10个，发生率分别为13．7％、7．8％、2．4％、1．5％、0．8％。突出、脱出和滑脱病例发生率较高（辟0．00）。女性发生率高于男性（P=0．005）。40岁以上是Modic改变发生较多的年龄段（P=0．001）。椎间盘退变程度、椎间盘节段与年龄均和Modic改变具有显著相关性（P=0．000）。回归方程为Y=-5．955＋0．198A＋1．528L＋1．883D（Y为M0dic改变，A为年龄，L为椎间盘节段，D为椎间盘退变程度），P=0．000，EXP值：D=6．571，L=4．609，A=1．220。结论腰椎终板Modic改变和椎间盘退变、椎间盘节段和年龄之间存在相关关系，椎间盘退变是最重要的影响因素。Modic改变Ⅱ型最多，Ⅰ型次之，Ⅲ型最少；多发生于L4-5和L5S1椎间盘节段；女性高于男性；40岁以上是易发年龄。     

正钒酸钠对椎间盘软骨细胞功能的抑制作用

目的探讨正钒酸钠（Sodium Orthovanadate，Na3VO4）对椎间盘软骨终板软骨细胞的作用。方法使用酶消化法培养大鼠椎间盘软骨终板软骨细胞，以10、20及30umol／L不同浓度Na3VO4干预第三代软骨细胞。培养7d后，用MTT法检测软骨细胞增殖率，RT-PCR检测Ⅱ型、Ⅸ型胶原和蛋白聚糖（Aggrecan）mRNA的表达，定量RT—PCR检测PTPN1、IGFRmRNA的表达。结果与对照组比较：（1）10umol／L Na3VO4组上述各项检测指标变化不明显，差异无统计学意义；（2）20及30umol／L Na3VO4组软骨细胞增殖率下降（q=31．51，81．42，P〈0．01）、Aggrecan（q=52．09，102．55，P〈0．01）和PTPN1（q=7．67，4．74，P〈0．01）mRNA表达降低；（3）30umol／L Na3VO4组Ⅱ型胶原（q=51．46，P〈0．01）、Ⅸ型胶原（q=8．62，P〈0．01）mRNA表达降低；（4）各浓度Na3VO4组IGFRmRNA均增加（q=13．96，7．67，4．74，P〈0．01）。结论20及30umol／L Na3VO4可抑制椎间盘软骨细胞增殖，降低Ⅱ、Ⅸ型胶原、Aggrecan以及PTPN1的mRNA表达，说明Na3VO4对软骨细胞中PTPs的活性有抑制作用，从而降低了软骨细胞生物学功能。但Na3Vo4对IGFR mRNA无抑制作用，并可能有一定的促表达作用。     

Quantification of in-plane motion of the coronary arteries during the cardiac cycle: Implications for acquisition window duration for MR flow quantification

Motion of the coronary arteries during the heart cycle can result in image blurring and inaccurate flow quantification by MR. This condition applies particularly for longer acquisition windows that are typical of breath-hold coronary flow measurements. To determine the sensitivity of the technique to in-plane motion of different coronary arteries, the temporal variation in coronary position was measured in a plane perpendicular to the proximal portion of the vessel. The results indicated the presence of substantial displacement of the coronary arteries within the cardiac cycle, with a magnitude of motion approximately twice as large for the right as for the left coronary arteries. An estimation of the resulting vessel blurring was calculated, showing that the duration of the acquisition window for high spatial resolution coronary flow acquisitions should be less than 25 to 120 msec, depending on the specific coronary artery studied. In addition, these data specify optimal acquisition window placement for high resolution coronary angiography.