摘要
本文介绍了影像诊断学,尤其是磁共振和CT 的发展现状,以及今后的发展方向。磁共振(MR)是影像诊断技术中最为活跃、发展最快的技术。MR 机的磁体有更多使用紧凑型的趋势;磁场强度虽无明显增强,但通过提高动态匀场的均匀度,低场磁共振的性能不断提高,因此,低场MR 机的市场将与中场 MR 机一样有所增长。MR 机发展的重要方面是涉及到快速和高分辨成像的梯度系统性能的改善和提高。新的 MR 成像技术包括弥散和灌注成像、MR 血管造影、MR 胰胆管造影及全身 MR 成像。弥散成像主要依靠分子的布朗运动,能诊断超早期脑卒中;灌注成像是静脉注射高浓度 Gd-DTPA 后,进行 MR 动态成像,可评价微血管的状态和功能。临床上主要用于肿瘤的早期诊断及鉴别诊断,以及超早期脑卒中的诊断。MR 血管造影(MRA)实际上是血流成像,通常不需要注射造影剂。由于采用磁化传递对比、可变翻转角、滑动交织多个重叠块等技术,且后处理采用高密度图像重建以及图像过滤,使 MRA 的图像质量进一步提高。对比增强MRA、动态图像采集及相减、MR 数字减影血管造影等技术亦开始应用。MR 冠状动脉造影需使用专用相控阵线圈、导航技术、回波平面成像、螺旋 MR 等设备和技术。它适用于筛选需行导管冠脉造影的患者和综合评价冠脉功能,但尚不能作为常规的检查方法。MR 胰胆管造影(MRCP)是应用液体成像技术,无创性显示胰胆管系统,能清楚揭示阻塞性黄疸病人的阻塞部位,有很大的实际应用价值。全身 MR 成像已有报道,其全身扫描仅需18秒,为体检、普查提供了一个新方法。MR 今后的发展将分为三个阶段。现阶段主要是提高 MR 的性能、速度以及开发专用 MR 机;以后的2-5年间将开发新的系列脉冲序列,如综合性心脏、脑检查,人机交往 MR,智能化采集及导航技术;5年后,MR 可进行组织的�
This paper briefly describes the future development of diagnostic imaging with emphasis on CT and MR.MR technology is very active and fast developing.There is a tendency toward using compact magnet with its less helium boil-off rate,shotter magnets,yet good field homogeneity due to automatic dynamic FOV shim- ming.Low field magnet with its open design and improved performance,is growing in terms of market share. New MR technology includes functional MRI(diffusiod,perfusion and cortical activation)advanced MRA, MRCP and total body MRI.Diffusion imaging is useful in diagnosing hyper-acute stroke,while perfusion im- ages microvasculature,important in early diagnosis,are differential diagnosises of malignancy.MRA is much improved with the incorporation of new techtniques such as MTC,TONE,Multi-slav,Sliding interleaving multislav,high density image reconstruction image fitter,and etc.Contrast entranced(CE)MRA,dynamic image acquisition and subtraction,and MR-DSA are also employed in clinical applications.Coronary MRA is the most challenging.New—techniques include the use of dedicated cardiac phased-away coil Navigation pulse, EPI and special MR,and Coronary MRA,Although much improved in image quality and length of visualiza- tion,these are still under clinical evaluation.MRCP,a type of liquid imaging,is being extensively used in the investigation of abstractive jaundice.Being noninvasive,MRCP can localize the site of obstruction and in many cases,determine the cause of obstruction.A preliminary study in total body MRI was reported,which using EPI,took only 18 seconds.Implying the possible use of MRI screening.The future development of MRI might be considered to progress in 3 steps:(1)Present:further improvement of MR performance,imaging speed and dedicated MR scanner;(2)2～5 years:New series of pulse sequences,comprehension cardiac and brain studies interactive MR,Navigation techtnique;(3)5 years later:tissue characterization,quantification,serial study; including screening-detection diagnosis-staging-MR girded ther
出处
《当代医学》
1997年第2期105-111,共7页
Contemporary Medicine
关键词
影像学
磁共振
计算机断层
脑磁图
仿真技术
激光相机
数字摄影
Imaging diagnosis
magnetic Resonance
Tomography X-ray computed
Magneto encephalog raphy
Virtual reality
laser imagery
Digital Radiography
