CAJ | 학술논문

目的探索腹部血管成像64排螺旋CT低剂量扫描的可行性和合理性.方法采用120 kV、200～30 mAs之间每次降低10 mAs的条件进行模体测试图像采集,测量其CT值的标准差(SD)、高对比密度分辨率与低对比密度分辨率,分析三者与扫描所用mAs值的联系,找到3个mAs值进行临床病例分析.随机选取90例行腹部血管检查的患者平均分为3组,采用以上mAs值进行图像采集,进行平扫常规剂量SD值测量,并对增强低剂量扫描进行三维容积重建(VR),再由3名CT诊断医师采用盲法评价进行VR图像质量评估,按优、中、差3个等级进行评定.3组平扫SD值与腹部血管成像VR图像进行质量相关性分析.结果 3组平扫SD值与腹部血管成像VR图像的质量相关性分析ROC曲线下面积分别为0.921、0.906、0.893.结论腹部血管成像低剂量扫描切实可行,80 mAs可以较好地保证图像质量.在平扫SD值小于5.78时增强扫描可以采用60 mAs,而当平扫SD值大于11.8时增强扫描最好采用100 mAs或更高的mAs值.
목적 탐색복부혈관성상64배라선CT저제량소묘적가행성화합이성.방법 채용120 kV、200～30 mAs지간매차강저10 mAs적조건진행모체측시도상채집,측량기CT치적표준차(SD)、고대비밀도분변솔여저대비밀도분변솔,분석삼자여소묘소용mAs치적련계,조도3개mAs치진행림상병례분석.수궤선취90례행복부혈관검사적환자평균분위3조,채용이상mAs치진행도상채집,진행평소상규제량SD치측량,병대증강저제량소묘진행삼유용적중건(VR),재유3명CT진단의사채용맹법평개진행VR도상질량평고,안우、중、차3개등급진행평정.3조평소SD치여복부혈관성상VR도상진행질량상관성분석.결과 3조평소SD치여복부혈관성상VR도상적질량상관성분석ROC곡선하면적분별위0.921、0.906、0.893.결론 복부혈관성상저제량소묘절실가행,80 mAs가이교호지보증도상질량.재평소SD치소우5.78시증강소묘가이채용60 mAs,이당평소SD치대우11.8시증강소묘최호채용100 mAs혹경고적mAs치.
Objective To explore the feasibility and reasonable of low-dose scan on abdominal angiography in 64-slice spiral helical CT. Methods Phantom test: at 120 KV and from 200 mAs to 30 mAs at an interval of 10 mAs in each image acquisition, it was measured standard deviation (SD) of CT number, high contrast resolution and low contrast resolution, and then analyzed the relationship between the three parameters and the mAs values. Three mAs values were chosen to undertake clinical analysis.Clinical analysis: 90 randomly selected objects with abdominal angiography were divided into three groups,scanning with above three mAs values.Measurement of the SD value at the plain scan images was performed and the enhanced low-dose scan images were used post-processing with three-dimensional volume reconstruction (VR). The VR images were classified into three grades (excellent, moderate, bad) with the blind evaluation of three CT radiologists. The quality-correlation analysis was used between the standard deviation (SD) values of plain scan image and abdominal angiography VR image. Results According to the quality-correlation analysis between the standard deviation (SD) value of plain scan image and abdominal angiography VR image, the area under curve in receiver-operated characteristic (ROC) analysis was 0.921, 0.906 and 0.893 in each three group, respectively. Conclusions The low-dose scan of abdominal angiography is feasible. 80mAs can ensure better image quality. The enhanced scan probably can use 60mAs when the SD value is less than 5.78 in the plain scan; but when the SD value of plain scan is greater than 11.8, the enhanced scan is used best 100 mAs or higher.