颞骨低剂量CT扫描的应用研究  

The Study of Low-dose CT in Temporal Bone Scanning

作　　者：华建明[1] 陈根松[1] 丁信法[1] 向可伟[1] 章伟敏[1] 

机构地区：[1]浙江大学医学院附属第二医院放射科,浙江杭州310009

出　　处：《实用放射学杂志》2006年第2期170-172,共3页Journal of Practical Radiology

基　　金：浙江省卫生厅基金资助项目(2002B025)。

摘　　要：目的探讨颞骨高分辨率CT扫描时降低扫描mA值对其图像质量的影响及临床应用价值。方法将60例颞骨高分辨率冠状面CT扫描患者根据扫描mA值设置分为100mA和50mA组。全部图像行高分辨率骨密度算法重组,并利用多平面重建(MPR)技术重建轴面图像,得到2组不同mA值的直接扫描冠状面图像和与之对应的2组通过重建的轴面图像。分别评价不同扫描mA时直接冠状面及重建轴面图像质量。评价指标为:冠状面:鼓室盾板、Prussak’s腔、卵圆窗、鼓室盖、耳蜗底圈5个解剖结构。经MPR重建轴面:锤砧关节、水平半规管、鼓窦入口、锥隆起、面神经水平段5个解剖结构;评价标准为:清晰显示2分;显示、但不清晰1分;未显示0分。以左右两侧单独记分。结果当扫描mA值由100减至50时单次扫描加权CT剂量指数量(CTDIw)值由42.00mGy下降至21.00mGy,下降幅度达50.0%,而直接扫描冠状面图像质量无明显下降(P>0.05);并且颞骨低剂量高分辨率CT能基本达到图像向同性,经MPR重建的轴面图像能较好地显示颞骨细小解剖结构,保证病灶检出率。结论50mA的颞骨CT扫描能够提供较好诊断质量的影像信息。Objective To investigate the influence on the quality of image and clinical application of temporal bone high resolution CT by decreasing scan mA value . Methods According to scanning mA value , 6 0 patients undergone temporal bone high resolution CT were divided into two groups： 100mA and 50mA. Two groups of direct coronal images with different mA values and corresponding reconstruction of axial plane images were obtained by bone algorithm recombination and multiplanar reformation （ MPR ） technology. The quality of coronal plane and axial plane at different scanning mA values were evaluated respectively. Assessment indications included： （ 1 ） Coronal plane： scutum of tympanic cavity, Prussak＇ s space, oval window, tympanic tegmen and cochlear chassi totally five anatomic structures ; （ 2 ） MPR axial plane ： incudomalleolar joint, horizontal semicircular canal, tympanic antrum opening, phyramidal emimence and horizontal segment of the facial never totaly five anatomic structures. Assessment standards according to the displaying condition of these structures were scored： clearly displayed scored 2, unclearly displayed scored 1 and undisplayed scored 0. Left and right sides were scored individually. Results When the scan mA value was decreased from 100 to 50 , single scan weighting CTDIw value decreased from 42.00 mGy to 21.00 mGy ,the decreasing extent reached 50% ,and there was not obvious drop of quality in direct scan coronal images （P 〉 0.05 ） ; Furthermore, temporal bone low dose high resolution CT could keep consistent basically . The reconstruction axial plane images by MPR could display the small anatomic structure of temporal bone well and ensured the detectable rate of focus. Conclusion 50mA temporal bone CT can provide imaging information with a better diagnostic quality.

关 键 词：颞骨 低剂量 体层摄影术 X线计算机 

分 类 号：R323.1[医药卫生—人体解剖和组织胚胎学] R814.42[医药卫生—基础医学]