Update on sports imaging

Sports Imaging has dramatically increased in the past decade with increasing number of adolescents, young and middle-aged adults participating in non-competitive/hobby sports. Therefore, sports injuries are no longer confined to elite athletes. Furthermore, newer forms of sports such as mountain climbing, pickle ball and curling etc. are gaining popularity. Majority of the injuries in sports medicine are from musculoskeletal trauma. Therefore, it is imperative that the musculoskeletal radiologist becomes familiar with various sports related injury patterns as these are commonly encountered in daily practice. This update aims to briefly encapsulate the major aspects of sports imaging. It includes the imaging manifestations of various types of musculoskeletal injuries on different modalities (commonly US and MRI) and briefly mentions the various image guided interventions, performed both on the sports field and in the hospital setting.     

MRI图像融合技术在肛瘘评估中的初步应用

目的采用图像融合技术获得T2WI与T2WI-FS的融合图像，评估其在肛瘘及肛周结构显示中的优势。 方法2016年6月至2018年6月，前瞻性选择中山大学附属第一医院29例肛瘘患者进行肛管磁共振（MR）检查，采用图像融合技术获取T2WI与T2WI-FS的融合图像T2WI-Fusion，利用Fisher score算法计算瘘管及肛门括约肌的组织间分辨力Fisher值、脂肪与肛门括约肌间的Fisher值，评估融合图像中瘘管及肛周结构的显示情况。采用改进的双刺激连续质量量表（DSCQS）对T2WI-FS、T2WI、增强3D-VIBE和T2WI-Fusion序列图像进行主观图像质量评价。 结果29例患者均成功获得T2WI与T2WI-FS的融合图像T2WI-Fusion。T2WI-Fusion、T2WI瘘管与括约肌间Fisher均值分别为6.46、3.31，T2WI-Fusion图像对瘘管的显示优于T2WI序列图像（P<0.001）。T2WI-Fusion、T2WI-FS脂肪与括约肌间Fisher均值分别为10.61、2.45，T2WI-Fusion图像对括约肌的显示优于T2WI-FS序列图像（P<0.001）。T2WI-Fusion对瘘管与括约肌的图像质量评价总评分均高于T2WI-FS、T2WI、增强3D-VIBE序列（P<0.001）。 结论MRI图像融合技术同时具备T2WI及T2WI-FS的优势，无需增加扫描序列及扫描时间，且操作简单，花费时间短，显著提高病变及肛周解剖结构的对比度和图像质量。     

使用棱镜重新定位双侧中心暗点患者视网膜物像的预试验

目的 本研究使用激光扫描检眼镜(SLO)评价双侧中央暗点患者使用棱镜后的眼球运动反应.方法 本预试验共招募6例有双侧中央暗点的年龄相关性黄斑变性(AMD)患者以及6例正常视力的志愿者.首先用Nidek MP-1微视野仪确认患者的中央暗点和优选视网膜注视点(PRL),然后用Rodenstock SLO,在将视标投射在优选视网膜注视点时拍下实时视网膜像,接着在受检者眼前加入6～8 PD的棱镜,要求受检者保持注视视标,这时通过视网膜标记来测量视网膜像的移位量,以及随后发生的优选视网膜注视点的再次注视.过程中平均移位量和再次注视时间通过图像软件(ImageJ software)来计算.结果 实验组再次注视时的移位量在3个像素点或11.66个弧分之内(x轴:2.90±3.92,y轴:2.53±4.18).对照组再次注视时的移位会准确些(x轴:0.33±1.15,y轴:0.89±2.50),但与实验组差异无统计学意义(tx=1.32,Px＞0.05;ty=0.80,Py＞0.05).对照组再次注视时间(0.98±0.19)s较实验组(2.83±1.63)s要短,差距有统计学意义(t=5.03,P＜0.01).其中有1例实验组受检者没有发生再次注视,其结果被排除并单独分析.结论 研究发现,双眼中央暗点患者对棱镜物像转移后的再注视反应与正常人接近,但实验组再注视明显较对照组慢,并有1例受检者没有发生再注视.该数据说明双侧中央暗点患者无论眼前有没有棱镜,都会利用相同的视网膜位置视物,因此,通过棱镜物像再定位的意义不大.     

基于机器学习的脑胶质瘤多模态影像分析

脑部胶质瘤是临床中常见的一种原发性脑肿瘤，具有复发率高、死亡率高以及治愈率低的特点。常规临床诊断主要依靠计算机断层扫描(CT)和磁共振成像(MRI)检查技术进行鉴别。随着成像技术和机器学习方法的不断发展，多模态影像智能分析技术已经逐步成为研究热点，在脑胶质瘤的病灶分割测量、肿瘤分级、预后生存周期预测和基因型辨别等方面具有重要的应用前景。本文重点介绍基于机器学习和多模态影像在脑胶质瘤临床辅助诊断和预后评估中的应用进展。     

Robust rigid registration of retinal angiograms through optimization

Retinal fundus photographs are employed as standard diagnostic tools in ophthalmology. Serial photographs of the flow of fluorescein and indocyanine green (ICG) dye are used to determine the areas of the retinal lesions. For objective measurements of features, the registration of the images is a necessity. In this paper, we employ optimization techniques for registration with the help of 2-parameter translational motion model of retinal angiograms, based on non-linear pre-processing (Wiener filtering and morphological gradient) and computation of the similarity criteria for the alignment of the two gradient images for any given rigid transformation. The optimization methods are effectively employed to minimize the similarity criterion.

The presence of noise, the variations in the background and the temporal variation of the fluorescence level pose serious problems in obtaining a robust registration of the retinal images. Moreover, local search strategies are not robust in the case of ICG angiograms, even if one uses a multiresolution approach.

The present work makes a systematic comparison of different optimization techniques, namely the minimization method derived from the optical flow formulation, the Nelder-Mead local search and the HCIAC ant colony metaheuristic, each optimizing a similarity criterion for the gradient images. The impact of the resolution and median filtering of gradient image is studied and the robustness of the approaches is tested through experimental studies, performed on macular fluorescein and ICG angiographies.

Our proposed optimization techniques have shown interesting results especially for high resolution difficult registration problems. Moreover, this approach seems promising for affine (6-parameter motion model) or elastical registrations.     

Location and geometric description of carpal bones in CT images

The carpal regions of ten cadaver extremities were imaged by CT. The images were combined into a 3-dimensional model of the carpus using a technique based on a dynamic programming algorithm to find an optimal estimate of the location of the bone boundaries in the CT images. The resulting set of surface points on each bone was used to compute volumes and principal and antipodal axes for the bones. A spatial coordinate system was established based on the positions of the centroids of three bones in the distal carpal row. The angular orientations of all carpal bones were determined with respect to this system. The principal axes for the same bone among ten wrist specimens proved to be more widely dispersed than the antipodal axes for the same bones. The antipodal axes also correspond more closely to an intuitive notion of the “longest axis” of the bones. We conclude that the antipodal axis is a more reliable and useful measure of bone orientation than the principal axis.     

Long-term neurotoxicity of chlorpyrifos: spatial learning impairment on repeated acquisition in a water maze.

Organophosphate compounds are cholinesterase inhibitors widely used in agriculture, industry, household products, and even as chemical weapons. Their major mechanism of acute toxic action is the inhibition of acetylcholinesterase, which is responsible for the degradation of the neurotransmitter acetylcholine. An organophosphorus ester-induced chronic neurotoxicity (OPICN) syndrome has been proposed. The OPICN syndrome could result from both long-term exposure to subclinical doses of OPs and after acute poisoning. Development of animal models for the cognitive decline are required and could later help to elucidate the mechanisms involved in this long-term effect on the central nervous system. Previously, we have found performance decrements in a four-trial repeated acquisition spatial task in a water maze. The present study includes two experiments to extend the long-term behavioral effects observed. Rats were injected either once or twice with chlorpyrifos (CPF) and then tested months after in a two-trial repeated acquisition task in a water maze. Our results confirm and extend the long-term behavioral effects of subcutaneous administration of CPF. The two treatments used produced performance decrements that suggest functional central nervous system alterations.     

Measuring behaviour: The tools and the strategies

Animal behaviour can be viewed as a stream of elements, which, once accurately described, can be counted and timed. Data acquisition techniques and tools are reviewed, and some strategies for collection and analysis of data using PC computers are suggested. Automated instruments are not satisfactory for the study of complex behaviour and as such systemic observation remains irreplaceable. IBM PC-type computers, with a wide range of analytical software (e.g., spreadsheets, statistical packages, technical graphics), are practical for data acquisition. Several systems which can satisfy different applications are reviewed. Some systems can communicate with a videorecorder, a facility which remarkably increases the accuracy of measurement; this is essential for meaningful analyses of the internal structure of behavioural streams (sequences, time patterns) or communication processes. The power of new tools enables behavioural measurement with the necessary complexity to allow a whole new set of questions to be addressed. However, it also increases demands for meaningful content and analysis of data.