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1.
A method is presented for 3D MRI in an extended field of view (FOV) based on continuous motion of the patient table and an efficient acquisition scheme. A gradient-echo MR pulse sequence is applied with lateral (left-right (L/R)) frequency-encoding direction and slab selection along the direction of motion. Compensation for the table motion is achieved by a combination of slab tracking and data alignment in hybrid space. The method allows fast k-space coverage to be achieved, especially when a short sampling FOV is chosen along the direction of table motion, as is desirable for good image quality. The method can be incorporated into different acquisitions schemes, including segmented k-space scanning, which allows for contrast variation with the use of magnetization preparation. Head-to-toe images of volunteers were obtained with good quality using 3D spoiled gradient-echo sequences. As an example of magnetization-prepared imaging, fat/water separated images were acquired using chemical shift selective (CHESS) presaturation pulses. 相似文献
2.
We have carried out a prospective randomised, single blind clinical trial to investigate the effect of continuous passive motion on range of knee flexion, lack of extension, pain levels and analgesic use after total knee replacement surgery. 85 subjects were randomly allocated to control or study group. All subjects followed the existing rehabilitation protocol, which permits immediate active range of motion exercises and mobilisation with the study group using continuous passive motion for 1 h, twice a day. Outcome measures employed were range of motion, pain assessed on a visual analogue scale and analgesic use according to the WHO ladder. Blinded evaluation was carried out preoperatively, at time of discharge from hospital, 6 weeks, 6 and 12 months postoperation. No significant difference was observed between groups at all time intervals for each outcome variable using Wilcoxon Rank sum tests. The results substantiate previous findings that short duration continuous passive motion following total knee arthroplasty does not influence outcome of range of motion or reported pain. 相似文献
3.
Turboprop: improved PROPELLER imaging. 总被引:1,自引:0,他引:1
A variant of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) MRI, called turboprop, is introduced. This method employs an oscillating readout gradient during each spin echo of the echo train to collect more lines of data per echo train, which reduces the minimum scan time, motion-related artifact, and specific absorption rate (SAR) while increasing sampling efficiency. It can be applied to conventional fast spin-echo (FSE) imaging; however, this article emphasizes its application in diffusion-weighted imaging (DWI). The method is described and compared with conventional PROPELLER imaging, and clinical images collected with this PROPELLER variant are shown. 相似文献
4.
NICOLAY GENOV BRUNO FILIPPI PAVLINA DOLASHKA KEITH S. WILSON CHRISTIAN BETZEL 《Chemical biology & drug design》1995,45(4):391-400
The stability towards thermal and chemical (guanidine hydrochloride, GnHCl) denaturation of six inhibited subtilases (mesentericopeptidase, subtilisins BPN′, Carlsberg and DY, proteinase K and thermitase) has been investigated by kinetic and equilibrium studies. The unfolding processes were monitored by circular dichroic and fluorescence spectroscopy. Experiments in the absence and presence of extraneous calcium in the concentration range 2×10?3-10?1 M were performed. The presence of calcium in the weak calcium binding site changes the denaturation drastically. The heat- (or GnHCl-) induced unfolding curves obtained using CD spectroscopy show two independent transitions which seem not to have been resolved before. The presence of Ca2+ in the second (third in the case of thermitase) binding site increases the Tm, values by 11-21 °C and the δGD(H2O) values obtained from denaturation experiments in GnHCl by 6.7-7.2 kcal/mol when an extraneous Ca2+ concentration of 2 × 10?2 M was used. One interpretation is that the initial step of denaturation in the presence of added calcium is the formation of a partially unfolded intermediate form, retaining a highly ordered structure with 60-85% of the a-helix structure of the native enzyme. This intermediate then unfolds at a temperature considerably higher than that of the same proteinases in the absence of added Ca2+. The free energy of stabilization of the intermediates is increased by 1.8-2.8 times in comparison with that for the unfolding reactions of the subtilases with empty Ca2/Ca3 binding sites. A second interpretation is that the two steps in the unfolding curves correspond to enzyme without and with calcium in the weak binding site. Fluorescence experiments confirm the mechanism involving the formation of intermediate states. The results are discussed in relation to the X-ray models of the six subtilases. 相似文献
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目的 探讨CPM在髌骨骨折改良张力带内固定术后的应用效果。方法 早期应用CPM治疗髌骨骨折行改良张力带内固定术后病人156例。结果 所有病例均得到随访,临床疗效优良率为98%。结论 在髌骨骨折行改良张力带内固定术后早期应用CMP,可显著利于膝关节功能恢复,提高治愈率。 相似文献
8.
定量组织速度成像对右室起搏患者左室收缩运动的研究 总被引:1,自引:0,他引:1
目的 应用定量组织速度成像 (QTVI)评价右室心尖起搏 (RVAP)VVI型对左心收缩功能的影响。方法 应用GEVivid 7彩色多普勒超声显像仪对 2 0例RVAP患者和 2 0例正常人的心尖四腔切面的室间隔和左室外侧壁速度和位移曲线进行观察 ,测量心电图Q波分别至室间隔和左室外侧壁收缩期峰速度的时间 ,并除以R R间期进行校正。结果 QTVI显示右室起搏器置入者的室间隔与左室外侧壁速度曲线的收缩期S波非同步出现。Q波至室间隔收缩期峰速度的时间短于Q波至左室外侧壁收缩期峰速度的时间 ,两者分别为 ( 0 .12± 0 .0 2 )s和 ( 0 .14± 0 .0 2 )s,P <0 .0 5。结论 右室起搏后早期的左室整体收缩功能虽未见明显下降 ,但QTVI可以发现室间隔与左室壁收缩明显的不协调 ,可作为早期分析左室收缩运动的定量方法。 相似文献
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10.
In the attempt to gain a broader understanding of the causal relationships behind work-related symptoms of pain in the human
shoulder, monitoring of arm position is crucial. Different methods have been used with varying accuracy. A video-based stereometry
system, using infra-red light and reflecting markers for motion analysis, has been introduced for measurements in the fields
of ergonomics, biomechanics and sports medicine. The purpose of this study is to investigate the sources of error in using
this system for posture registration of the upper limb. Measurements are performed on a calibration fixture, on a mechanical
model of the upper limb and on a subject with an exoskeleton. Particular, attention is given to inconsistencies and relative
errors due to the finite geometrical precision with which the markers are positioned in the calibration fixture and on the
studied objects, the limited capability to align the objects relative to the coordinate system of the calibration fixture
and the errors connected to angular measurements using protractors etc. It is concluded that the system makes a valuable addition
to existing instruments for non-contact posture measurement, and produces position data with an adequate accuracy in normal
handling. 相似文献