宝石CT碘-水基图在急性脑梗死介入治疗后的应用

目的探讨宝石CT碘-水基图在急性脑梗死介入治疗后的诊断价值。方法 31例急性脑梗死患者介入治疗后即刻宝石CT平扫QC图发现颅内异常高密度影,采用碘-水基图进行重建分析,同时测定高密度影碘基值、水基值,并与术后24 h普通CT复查诊断结果作比较。结果通过采用碘-水基图,17例诊断为碘对比剂渗出,14例诊断为脑出血转化,与术后24 h普通CT复查诊断结果完全一致(Kappa=1,P0.01);术后即刻碘基图之碘基值:碘对比剂渗出(32.09±5.36) g/L,脑出血转化(6.86±2.26) g/L,二者差异有统计学意义(t=53.291,P0.01);术后即刻水基图之水基值:碘对比剂渗出(1 027.93±8.29) g/L,脑出血转化(1 069.68±7.18) g/L,二者差异有统计学意义(t=-8.897,P0.01)。结论宝石CT碘-水基图可以准确诊断急性脑梗死介入治疗后颅内碘对比剂渗出和脑出血转化,值得向临床介绍推广。     

Fat and water separation in balanced steady-state free precession using the Dixon method.

In this work the feasibility of separating fat and water signals using the balanced steady-state free precession (SSFP) technique is demonstrated. The technique is based on the observation (Scheffler and Hennig, Magnetic Resonance in Medicine 2003;49:395-397) that at the nominal values of TE = TR/2 in SSFP imaging, phase coherence can be achieved at essentially only two orientations (0 degrees and 180 degrees ) relative to the RF pulses in the rotating frame, under the assumption of TR < T2, and independently of the SSFP angle. This property allows in-phase and out-of-phase SSFP images to be obtained by proper choices of the center frequency offset, and thus allows the Dixon subtraction method to be utilized for effective fat-water separation. The TR and frequency offset for optimal fat-water separation are derived from theories. Experimental results from healthy subjects, using a 3.0 Tesla system, show that nearly complete fat suppression can be accomplished.     

新时期戏剧艺术探索的成就与困顿

八十年代初中期 ,中国戏剧积极拓展我国传统戏剧的时空观、写意性特征 ,大胆借鉴西方现代戏剧的荒诞化、意象性技巧 ,出现了探索创新、多元发展的崭新局面。其中对“三一律、一堵墙”戏剧观的突破 ,运用意识形象外显人物的内心世界 ,嫁接多种艺术手段将现实时空转化为艺术时空 ,是新时期戏剧艺术探索最突出的三项成就。而过分强调形式技巧 ,脱离观众欣赏习惯 ,致使演出市场萎缩 ,观众锐减 ,无疑是新时期戏剧艺术探索中面临的最大困顿。     

Rapidly enhancing hepatic hemangiomas at MRI: Distinction from malignancies with T2-weighted images

The purpose of this study is to describe a subset of atypical hepatic hemangiomas that enhance rapidly and diffusely and to determine whether heavily T2-weighted images could distinguish between atypically enhancing liver hemangiomas and hypervascular malignancies. A retrospective search of MR records identified seven patients with liver hemangiomas that demonstrated diffuse early enhancement and 23 patients with biopsy-proven malignant liver lesions that were hypervascular on dynamic gadolinium-enhanced MR images. Quantitative analysis of signal intensity measurements was performed on the T2-weighted images, heavily T2-weighted (TE < 140), and dynamic gadolinium-enhanced images. Blinded reader comparison of the T2-weighted images and gadolinium-enhanced images was performed. Hypervascular hemangiomas enhanced to a greater degree than hypervascular malignant liver lesions on the early phase gadolinium-enhanced images. Perilesional parenchymal enhancement was demonstrated in five cases of rapidly enhancing hemangiomas. Signal intensity and contrast-to-noise ratios on the heavily T2-weighted images of the hemangiomas were significantly greater than that of the hypervascular malignant lesions (P < .05). Hemangiomas were differentiated from the hypervascular malignant liver lesions with high accuracy (97–100%) by three blinded readers based on the T2-weighted images. A subset of hemangiomas have atypical rapid diffuse enhancement on dynamic gadolinium-enhanced images. These atypical hemangiomas can be distinguished from hypervascular malignant liver lesions on T2-weighted MR images.     

超声诊断甲状腺腺瘤与单发结节性甲状腺肿的价值

目的　探讨超声在甲状腺腺瘤与单发结节性甲状腺肿鉴别诊断中的价值。方法　对两种疾病的二维及彩色多普勒声像图进行分析并比较。结果　甲状腺腺瘤与单发结节性甲状腺肿比较 ,甲状腺大小、结节大小、结节内回声及周围回声组间差异均无统计学意义 (P >0 .0 5 ) ;结节边缘晕环及结节内部和周边血流信号差异有显著性 (P <0 .0 5 )。结论　单发结节性甲状腺肿易误诊为腺瘤 ,结节边缘晕环及结节内部和周边血流信号对鉴别诊断可提供帮助     

颅面部螺旋CT扫描技术及图像的质控

颅面部的 CT扫描检查主要包括颅脑面部上、下颌骨、中耳、内耳、鼻窦、眼眍、眼球及颞骨茎突等部位的扫描检查 ,上述部位的扫描检查的位置的摆法 ,层面的厚度、间距 ,扫描时间及螺距等参数的选择及扫描后图像的后处理工作对检查结果的诊断至关重要。上述参数任意一个选择不当及     

MRI顺磁性造影剂增强及护理

目的 :进一步探讨 MRI增强前后的准备与护理方法。材料与方法 :共增强 833例 ,男 5 85例 ,女 2 4 8例。使用顺磁性造影剂 Gd- DTPA,按 0 .2 m L/kg体重给药。其中双倍量增强 110例 ,增强前认真履行告知义务和签署同意书。发生造影剂外漏者给予鲜马铃薯片外敷。结果 :增强效果达良好以上共 82 5例 ,占 99% ,未发生严重负反应。 3例造影剂外漏 ,鲜马铃薯片外敷后 3h痊愈。结论 :增强前充分细致的准备是保证增强效果的重要因素。认真履行告知义务和签置同意书 ,不仅尊重了病人的权利 ,也是依法行医 ,保证医疗安全的需要     

How do monkeys view faces?—a study of eye movements

Face perception plays a crucial role in primate social communication. We have investigated the pattern of eye movements produced by rhesus monkeys (Macaca mulatta) as they viewed images of faces. Eye positions were recorded accurately using implanted eye coils, while neutral upright, inverted and scrambled images of monkey and human faces were presented on a computer screen. The monkeys exhibited a similar eye scan pattern while viewing familiar and unfamiliar monkey face images, or while viewing monkey and human face images. No differences were observed in the distribution of viewing times, number of fixations, time into the trial of first saccade to local facial features, and the temporal and spatial characteristics of viewing patterns across the facial images. However, there was a greater probability of re-fixation of the eye region of unfamiliar faces during the first few seconds of the trial suggesting that the eyes are important for the initial encoding of identity. Indeed, the highest fixation density was found in the eye region of all the face images. The viewing duration and the number of fixations per image decreased when inverted or scrambled faces were presented. The eye region in these modified images remained the primary area of fixation. However, the number of fixations directed to the eyes decreased monotonically from the upright images through the inverted versions to the scrambled face images. Nonetheless, the eyes remain the most salient facial substructure regardless of the arrangement of other features, although the extent of salience which they attain may depend both on the low level properties of the eyes and on the global arrangement of facial features. Electronic Publication     

Object-based three-dimensional X-ray imaging

A form of three-dimensional X-ray imaging, called Object 3-D, is introduced, where the relevant subject material is represented as discrete ‘objects’. The surface of each such object is derived accurately from the projections of its outline, and of its other discontinuities, in about ten conventional X-ray views, distributed in solid angle. This technique is suitable for many applications, and permits dramatic savings in radiation exposure and in data acquisition and manipulation. It is well matched to user-friendly interactive displays.     

Real-time automatic extraction of lumen region and boundary from endoscopic images

A new approach to the automatic extraction of the lumen region and its boundary for gastrointestinal (GI) endoscopic images is presented. First, a quasi region of interest, the darker regions of the image, is segmented using a region splitting scheme termed progressive thresholding. The centre of mass of this segmented region acts as a seed for further processing. Then the lumen region is obtained using a region growing technique called the integrated neighbourhood search (INS). A new quad structure based technique is introduced to enhance the INS speed significantly. A back projection algorithm is suggested to optimise the search for pixels belonging to the lumen region and boundary. A boundary-thinning algorithm is also proposed to remove the redundant pixels from the lumen boundary and to generate a connected single pixel width boundary. The proposed approach does not need a priori knowledge about the image characteristics. The experimental results indicate that the proposed technique enhances the speed of conventional INS by 45.5% to 28.6% based on the lumen size varying from 22,709 pixels to 4947 pixels. The main advantage of the proposed technique is its high-speed response that facilitates real-time analysis of endoscopic images.