动力髋螺钉治疗股骨转子间骨折54例分析

目的 探讨动力髋螺钉治疗股骨转子间骨折的治疗效果。方法 对54例股骨转子间骨折采取动力髋螺钉内固定，并进行疗效评价。结果 全部病例得到随访，平均随访时间2．8年，骨折愈合率100％，关节功能优良率92．60(50／54)。结论 动力髋螺钉是治疗股骨转子间骨折的理想方法。     

MR动态增强扫描在肝硬化中的应用

目的研究肝硬化动态增强扫描的特点。资料与方法对20例正常人和34例肝硬化患者行肝脏MR动态增强扫描,比较两组肝脏强化比、门静脉灌注分数。结果肝硬化组动脉期、门静脉期和延迟期强化比分别为0.255±0.155、0.64±0.268、0.55±0.245,均高于正常组,差异具有统计学意义。两组门静脉期的强化比均高于动脉期、延迟期的强化比。肝硬化组和正常组的门静脉灌注分数分别为2.90±2.74、3.88±2.62,肝硬化组门静脉灌注分数低于正常组,二者差异具有统计学意义。结论MR动态增强扫描可以观察肝硬化者肝脏血液灌注情况。     

Clinical validation of fully-automated contour detection for gated radionuclide ventriculography with a slant-hole collimator

A new fully-automated method for processing gated blood-pool images is presented and its clinical validity and performance for images with various noise levels are investigated using data obtained from a slant-hole collimator. The optimal preprocessing conditions are evaluated for the images with various noise levels to obtain the accurate ejection fraction, end-diastolic and end-systolic counts. This new method has successfully detected left ventricular contour in 92% of the 61 patients. The left ventricular ejection fraction obtained by the method related closely to that of contrast ventriculography (correlation coefficient r=0.90). The end-diastolic volume also had a good correlation with contrast ventriculography (r=0.90).     

The effect of testing method on stereoanomaly

Previous tests of stereoanomaly (a deficit in stereopsis for a given disparity direction, crossed or uncrossed) have employed stimuli in which physical contours are presented with large disparities at exposure durations too brief for eye movements. This study investigated stereoanomaly using alternative testing methods with two types of stimuli: (1) stereoscopic contours formed from dynamic random-element stereograms presented both briefly and continuously, and (2) afterimages of retinally disparate physical contours. The results from three experiments show that most subjects who are classified as stereoanomalous under conditions of brief exposure perform normally under conditions that allow long inspection periods while eliminating eye movements. These results suggest that anomalies in stereopsis previously reported may depend on the method of testing rather than on deficits in underlying neural mechanisms.     

孤立性肺结节MRI动态增强血流模式及其定量研究

目的:探讨M R动态增强对孤立性肺结节的鉴别诊断价值.材料和方法:对83例孤立性肺结节行M R动态增强,绘制MR动态增强时间-信号强度曲线,测量病灶的强化峰值(PH)、最大线性强化斜率(SS)、最大强化率(Emax)及1、2、3、4、5、6min时的信号强化率(E1、E2、E3、E4、E5、E6).结果:恶性结节及炎性结节的强化程度明显高于良性结节,恶性结节及炎性结节的PH、SS、Emax、E1～E6均明显高于良性结节(P＜0.01).恶性结节与炎性结节均强化明显,但两者之间的PH、SS、Emax、E1～E6无明显差异(P＞0.05).结论:MR动态增强能反映孤立性肺结节的血流动力学信息,对良、恶性结节的鉴别诊断有较高的临床应用价值.     

How to obtain high-accuracy image registration: application to movement correction of dynamic positron emission tomography data

When registering dynamic positron emission tomography (PET) sequences, the time-dependent changes in uptake pattern prevent registration of all frames to the first frame in a straightforward manner. Instead, a sequential registration of each frame to its predecessor may be used, provided the registration algorithm is completely free of bias. It is shown that most existing algorithms introduce a bias, the size of which depends on the pixel size and the signal-to-noise ratio of the data. The bias is introduced by the pixelisation of the underlying continuous process. All existing cost-functions are more or less sensitive to noise, and the noise reduction resulting from translating one image set relative to the other means that a small movement will always be detected in the cases where no actual movement has occurred. The problem is solved by an initial resampling of the reference volume into a representation with another image and pixel size. If the new representation is sensibly chosen it means that all possible transforms applied to the other image volume will yield approximately the same noise reduction, thereby removing the source of the bias. The described effect is demonstrated on phantom data, and its impact is shown on human data. Received 15 October 1997 and in revised form 9 February 1998     

Dynamic axial fixation

Summary Conventional external fixation systems neither inhibit motion at the fracture site sufficiently to permit primary bone healing, nor do they allow sufficient motion to encourage adequate external callus formation. Healing with such systems is therefore prolonged. These methods are usually reserved for the most severe fractures when internal fixation may be contraindicated. A unilateral, dynamic axial fixation system (Orthofix — registered trademark) is described which allows for simple conversion from a rigid to a dynamic mode, and so can be readily adapted to the changing physiological patterns of fracture repair.In 288 fresh fractures a success rate of 94% was achieved, with an average time to healing of 4.4 months. The incidence of pin-track infection was only 0.6%. The contribution which the mechanical and design features of the apparatus make to the results obtained is discussed.It is suggested that the system is capable of extending the range of indications for an externally mounted system to include many cases which would formerly have been treated by internal fixation, plaster cast or traction.

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Résumé Les systèmes conventionnels de fixation externe ne suppriment pas suffisamment la mobilité du foyer de fracture pour permettre une consolidation osseuse «per primam», pas plus qu'ils n'autorisent une mise en charge susceptible de favoriser la formation du cal. Avec ces systèmes la guérison est donc retardée. Ces méthodes sont habituellement réservées aux fractures les plus graves, lorsque l'ostéosynthèse interne paraît contrindiquée. On décrit ici un fixateur axial dynamique (Orthofix), dont l'utilisation peut être facilement convertie du mode rigide au mode dynamique, permettant ainsi de s'adapter à l'évolution du processus de consolidation des fractures.Dans une série de 288 fractures récentes, le pourcentage de succès est de 94%, avec un délai moyen de consolidation de 4,4 mois. Le taux d'infection sur fiches n'est que de 0,6%. On discute du rôle joué dans ces résultats par le dessin et les caractéristiques mécaniques de l'appareil.Les auteurs pensent que ce système peut permettre d'étendre les indications de la fixation externe à un grand nombre de cas qui relèvent actuellement de l'ostéosynthèse, du plâtre ou de la traction.

     

肝脏Gd-DTPA快速动态增强MRI的临床应用──较小HCC与FNH的动态增强表现

目的：运用梯度回波（ＧＲＥ）的快速场回波（ＦＦＥ）技术，对２０例肝肿块进行Ｇｄ－ＤＴＰＡ动态增强，旨在探明不同肿块的增强规律，提高肝肿块的诊断和鉴别诊断能力。材料与方法：选取经过其他影像学检查未确诊的２０例肝肿块，作常规自旋回波（ＳＥ）平扫后作Ｇｄ－ＤＴＰＡＦＦＥ序列快速动态增强扫描，分别测量病灶信号强度（ＳＩｌｅｓｉｏｎ），灶周正常肝脏信号强度（ＳＩｌｉｖｓｒ），背景噪声信号强度和标准差（ＳＩｎｏｉｓｅｃ±ｓ），计算不同病变不同时相的肝－病灶对比噪声比（Ｃ／Ｎ），描出不同肿块（本文只评价其中手术病理证实的１３例肿块，包括肝细胞癌１０例，局灶性结节增生３例的时间－病灶Ｃ／Ｎ曲线。结果：ＨＣＣ与ＦＮＨ两者曲线较接近（包括强化峰值和升降坡度），但在增强早期，ＨＣＣ的Ｃ／Ｎ值高于ＦＮＨ，３分钟以后二者强化值均下降，且ＦＮＨ的Ｃ／Ｎ值大于０，ＨＣＣ的Ｃ／Ｎ值小于０，此差异可持续１５～２０分钟。结论：不同的肝肿块，动态增强后的时间－Ｃ／Ｎ曲线不同，对ＨＣＣ及ＦＮＨ而言，增强早期（１分钟以内）及３分钟以后曲线差异较大，最有助于鉴别诊断。动态增强ＭＲ成像可作为肝脏常规ＳＥ序列成像的一种有效的补充方法。     

Computed tomography in aortobifemoral Y grafts

The fact that we have experience in assessing aortic aneurysms and the need for a noninvasive morphologic and hemodynamic method of examination for the follow-up of aortoiliac surgery motivated us to initiate a dynamic CT study of bifurcation prosthesis. Twenty-seven Y grafts (25 Dacron, 2 polytetrafluoroethylene) were studied by CT scan 1 month to 7 years postoperatively. There were normal CT findings in 16 patients, neointima formation in 6, graft occlusion (1 limb of the Y graft) in 3, and dilatation of the prosthesis in 2. Patent grafts showed enhancement of contrast medium. CT scans corresponded to clinical findings in all instances. Because of its noninvasiveness, assessment of perivascular changes, and semiquantitative measurements, dynamic CT may be applied in the follow-up of aortofemoral bifurcation grafts.     

应用冲击法进行人体坐姿模态参数识别的探讨

本文应用模态分析技术,研究人体动力学性特性。对5名被试者进行了着陆冲击试验。将座椅冲击力作为输入信号,将人体骼、腰、肩和头的加速度响应作为输出信号。用HP-5423A 结构动态分析仪进行人体模态参数识别,并绘制大量人体振型图。结果表明躯干自振频率为11～13Hz,阻尼比为21%。并获得第一阶,二阶模态质量,模态刚度,模态阻尼和固有振型。此结果在建模及分析冲击人体动力学特性与损伤是有价值的。