中华放射学杂志
中華放射學雜誌
중화방사학잡지
Chinese Journal of Radiology
2015年
4期
273-278
,共6页
胡茂清%叶维韬%梁长虹%刘再毅%温孟皇%李星云
鬍茂清%葉維韜%樑長虹%劉再毅%溫孟皇%李星雲
호무청%협유도%량장홍%류재의%온맹황%리성운
体层摄影术,X线计算机%造影剂%辐射剂量
體層攝影術,X線計算機%造影劑%輻射劑量
체층섭영술,X선계산궤%조영제%복사제량
Tomography,X-ray computed%Contrast media%Radiation dosage
目的 探讨管电压和碘对比剂浓度对腹部动态CT增强图像质量的影响.方法 采用4种扫描方案,对6只小型猪行腹部动态CT增强扫描.方案1:管电压80 kV、对比剂含碘270 mg/ml;方案2:管电压120 kV、对比剂含碘270 mg/ml;方案3:管电压80 kV、对比剂含碘370 mg/ml;方案4:管电压120 kV、对比剂含碘370 mg/ml.对方案1和方案3图像行迭代算法(iDose4)重组;方案2和方案4图像行常规滤波反投影(FBP)重组.各方案对比剂碘含量均为600 mg/kg,注射碘流率均为0.92 g/s(含碘270 mg/ml对比剂流率3.4 ml/s、含碘370 mg/ml流率2.5 ml/s).对各组图像进行主观评价,包括图像质量评分、图像噪声评分、图像锐利度评分;进行客观评价,测量主动脉、门静脉、肝静脉、下腔静脉及肝实质的强化CT值、噪声、达峰时间、信噪比(SNR)及对比噪声比(CNR),并记录扫描的CT剂量容积指数(CDTIvol)和剂量长度乘积(DLP).采用方差分析比较不同扫描方案下各血管和肝实质的强化CT值、噪声、SNR和CNR,采用非参数Kruskal-Wallis检验比较不同扫描方案下各血管和肝实质的达峰时间及图像评分.结果 4种方案扫描的主观图像质量、图像噪声和图像锐利度评分均＞3分,差异均无统计学意义(P均＞0.05).方案1～4扫描的主动脉强化峰值分别为(729±46)、(515±84)、(707±59)、(513±53)HU,下腔静脉强化峰值分别为(366±95)、(282±39)、(368±92)、(262±67)HU,门静脉强化峰值分别为(213±18)、(180±21)、(201±29)、(176±27)HU,肝静脉强化峰值分别为(207±18)、(179±24)、(193±10)、(170±14)HU,肝实质强化峰值分别为(128±7)、(135±5)、(127±4)、(135±6)HU,方案1和方案3、方案2和方案4比较,上述部位强化CT峰值差异均无统计学意义(P均＞0.05),且方案1、方案3的主动脉、下腔静脉、门静脉、肝静脉强化CT峰值高于方案2、方案4(P均＜0.05),方案1、方案3的肝实质强化CT峰值低于方案2、方案4(P＜0.05).方案1、方案3的主动脉、下腔静脉、门静脉、肝静脉噪声高于方案2、方案4(P均＜0.05),4组图像肝实质噪声差异无统计学意义(P均＞0.05).4种方案各部位达峰时间、SNR、CNR差异均无统计学意义(P均＞0.05).方案1和方案3的CDTIvol和DLP分别为199.67 mGy、1 597.4 mGy· cm.方案2和方案4(120 kV)的CDTIvol和DLP分别为585.12 mGy和4 680.9 mGy·cm.结论 不同浓度碘对比剂在相同碘流率和单位体质量碘用量时对上腹部血管及肝实质强化程度相同,80 kV扫描时血管强化程度高于120 kV.采用80 kV低剂量扫描时,结合迭代重建算法可以确保图像质量.
目的 探討管電壓和碘對比劑濃度對腹部動態CT增彊圖像質量的影響.方法 採用4種掃描方案,對6隻小型豬行腹部動態CT增彊掃描.方案1:管電壓80 kV、對比劑含碘270 mg/ml;方案2:管電壓120 kV、對比劑含碘270 mg/ml;方案3:管電壓80 kV、對比劑含碘370 mg/ml;方案4:管電壓120 kV、對比劑含碘370 mg/ml.對方案1和方案3圖像行迭代算法(iDose4)重組;方案2和方案4圖像行常規濾波反投影(FBP)重組.各方案對比劑碘含量均為600 mg/kg,註射碘流率均為0.92 g/s(含碘270 mg/ml對比劑流率3.4 ml/s、含碘370 mg/ml流率2.5 ml/s).對各組圖像進行主觀評價,包括圖像質量評分、圖像譟聲評分、圖像銳利度評分;進行客觀評價,測量主動脈、門靜脈、肝靜脈、下腔靜脈及肝實質的彊化CT值、譟聲、達峰時間、信譟比(SNR)及對比譟聲比(CNR),併記錄掃描的CT劑量容積指數(CDTIvol)和劑量長度乘積(DLP).採用方差分析比較不同掃描方案下各血管和肝實質的彊化CT值、譟聲、SNR和CNR,採用非參數Kruskal-Wallis檢驗比較不同掃描方案下各血管和肝實質的達峰時間及圖像評分.結果 4種方案掃描的主觀圖像質量、圖像譟聲和圖像銳利度評分均＞3分,差異均無統計學意義(P均＞0.05).方案1～4掃描的主動脈彊化峰值分彆為(729±46)、(515±84)、(707±59)、(513±53)HU,下腔靜脈彊化峰值分彆為(366±95)、(282±39)、(368±92)、(262±67)HU,門靜脈彊化峰值分彆為(213±18)、(180±21)、(201±29)、(176±27)HU,肝靜脈彊化峰值分彆為(207±18)、(179±24)、(193±10)、(170±14)HU,肝實質彊化峰值分彆為(128±7)、(135±5)、(127±4)、(135±6)HU,方案1和方案3、方案2和方案4比較,上述部位彊化CT峰值差異均無統計學意義(P均＞0.05),且方案1、方案3的主動脈、下腔靜脈、門靜脈、肝靜脈彊化CT峰值高于方案2、方案4(P均＜0.05),方案1、方案3的肝實質彊化CT峰值低于方案2、方案4(P＜0.05).方案1、方案3的主動脈、下腔靜脈、門靜脈、肝靜脈譟聲高于方案2、方案4(P均＜0.05),4組圖像肝實質譟聲差異無統計學意義(P均＞0.05).4種方案各部位達峰時間、SNR、CNR差異均無統計學意義(P均＞0.05).方案1和方案3的CDTIvol和DLP分彆為199.67 mGy、1 597.4 mGy· cm.方案2和方案4(120 kV)的CDTIvol和DLP分彆為585.12 mGy和4 680.9 mGy·cm.結論 不同濃度碘對比劑在相同碘流率和單位體質量碘用量時對上腹部血管及肝實質彊化程度相同,80 kV掃描時血管彊化程度高于120 kV.採用80 kV低劑量掃描時,結閤迭代重建算法可以確保圖像質量.
목적 탐토관전압화전대비제농도대복부동태CT증강도상질량적영향.방법 채용4충소묘방안,대6지소형저행복부동태CT증강소묘.방안1:관전압80 kV、대비제함전270 mg/ml;방안2:관전압120 kV、대비제함전270 mg/ml;방안3:관전압80 kV、대비제함전370 mg/ml;방안4:관전압120 kV、대비제함전370 mg/ml.대방안1화방안3도상행질대산법(iDose4)중조;방안2화방안4도상행상규려파반투영(FBP)중조.각방안대비제전함량균위600 mg/kg,주사전류솔균위0.92 g/s(함전270 mg/ml대비제류솔3.4 ml/s、함전370 mg/ml류솔2.5 ml/s).대각조도상진행주관평개,포괄도상질량평분、도상조성평분、도상예리도평분;진행객관평개,측량주동맥、문정맥、간정맥、하강정맥급간실질적강화CT치、조성、체봉시간、신조비(SNR)급대비조성비(CNR),병기록소묘적CT제량용적지수(CDTIvol)화제량장도승적(DLP).채용방차분석비교불동소묘방안하각혈관화간실질적강화CT치、조성、SNR화CNR,채용비삼수Kruskal-Wallis검험비교불동소묘방안하각혈관화간실질적체봉시간급도상평분.결과 4충방안소묘적주관도상질량、도상조성화도상예리도평분균＞3분,차이균무통계학의의(P균＞0.05).방안1～4소묘적주동맥강화봉치분별위(729±46)、(515±84)、(707±59)、(513±53)HU,하강정맥강화봉치분별위(366±95)、(282±39)、(368±92)、(262±67)HU,문정맥강화봉치분별위(213±18)、(180±21)、(201±29)、(176±27)HU,간정맥강화봉치분별위(207±18)、(179±24)、(193±10)、(170±14)HU,간실질강화봉치분별위(128±7)、(135±5)、(127±4)、(135±6)HU,방안1화방안3、방안2화방안4비교,상술부위강화CT봉치차이균무통계학의의(P균＞0.05),차방안1、방안3적주동맥、하강정맥、문정맥、간정맥강화CT봉치고우방안2、방안4(P균＜0.05),방안1、방안3적간실질강화CT봉치저우방안2、방안4(P＜0.05).방안1、방안3적주동맥、하강정맥、문정맥、간정맥조성고우방안2、방안4(P균＜0.05),4조도상간실질조성차이무통계학의의(P균＞0.05).4충방안각부위체봉시간、SNR、CNR차이균무통계학의의(P균＞0.05).방안1화방안3적CDTIvol화DLP분별위199.67 mGy、1 597.4 mGy· cm.방안2화방안4(120 kV)적CDTIvol화DLP분별위585.12 mGy화4 680.9 mGy·cm.결론 불동농도전대비제재상동전류솔화단위체질량전용량시대상복부혈관급간실질강화정도상동,80 kV소묘시혈관강화정도고우120 kV.채용80 kV저제량소묘시,결합질대중건산법가이학보도상질량.
Objective To investigate the effect of tube voltage and iodine concentration of contrast medium (CM) on abdominal dynamic enhanced CT image quality.Methods Six miniature pigs underwent repeated upper abdomen dynamic contrast-enhanced CT scans in 4 scanning protocols with different concentration of CM and tube voltage,namely,protocol 1,CM with iodine concentration of 270 milligrams iodine per milliliter (mg/ml) and 80 kV tube voltage;protocol 2,270 mg/ml and 120 kV;protocol 3,370 mg/ml and 80 kV and protocol 4,370 mg/ml and 120 kV.The same iodine dose (600 mg/ml) and iodine delivery rate (IDR) (920 mg/s) were used in all protocols.The CM with iodine concentration of 270 mg/ml were injected at a flow rate of 3.4 ml/s,and 370 mg/ml CM injected at 2.5 ml/s.Image reconstruction was performed with iterative reconstruction (iDose4) in protocol 1 and 3,filtered back projection (FBP) was used in protocol 2 and 4.A subjective scoring system for image quality,image noise and sharpness was conducted by 2 radiologists independently.The measured values (peak of enhanced CT values,image noise of aorta,inferior vena cava,portal vein,hepatic vein and liver parenchyma) as well as the calculated values [their time-to-peak,signal-to-noise (SNR) and contrast-to-noise (CNR) ratios] were compared between among 4 protocols.The CT volume dose index (CDTIvol) and dose length product (DLP) were recorded from the CT console after each scanning.Factorial designed ANOVA was used for comparison of enhanced CT values of vessels and liver parenchyma,noise,SNR and CNR.The Kruskal-Wallis test was used for comparison of values among the 4 protocols,including the time-to-peak enhancement of vessels and liver parenchyma,the subjective scores of image quality indices.Result There was no significant differences in subjective scores of the image quality,image noise and image sharpness (P＞0.05).The scored were more than 3,and the images with 4 scanning protocols were all acceptable for diagnosis.There was no significant differences between protocol 1 and 3,protocol 2 and 4 in the peak enhancement CT values of aorta [(729±46) HU vs.(707±59)HU,(515±84)HU vs.(513±53)HU],inferior vena cava [(366±95)HU vs.(368±92)HU,(282±39)HU vs.(262 ± 67)HU],portal vein [(213± 18)HU vs.(201 ±29)HU,(180±21)HU vs.(176±27)HU],hepatic vein [(207±18)HU vs.(193±10)HU,(179±24)HU vs.(170±14)HU] and liver parenchyma [(128±7) HU vs.(127±4) HU,(135±5)HU vs.(135±6)HU] (P＞0.05).But the CT values of vessels (aorta,inferior vena cava,portal vein and hepatic vein) in protocol 1 and 3 were significantly higher than those in protocol 2 and 4 (P＜0.05),the CT values of liver parenchyma in protocol 1 and 3 were significantly lower than values in protocol 2 and 4 (P＜0.05).The image noises of vessels were higher in protocol 1 and 3 than noises in other protocols (P＜0.05),but there was no significant difference in liver parenchyma noise among protocols (P＞0.05).No significant differences were observed on the peak times,SNR and CNR in aorta,inferior vena cava,portal vein,hepatic vein and liver parenchyma among 4 protocols (P＞0.05).The CDTIvol and DLP were 199.67 mGy,1 597.4 mGy· cm respectively in protocol 1 and 3,585.12 mGy and 4 680.9 mGy· cm in protocol 2 and 4 (scanning with 120 kV).Conclusions CM with different iodinated concentration could achieve the same enhancement in the abdominal vessels and liver parenchyma by using the proper scan protocols,which have the same IDR and iodine dose per kilogram body weight.Higher vessel enhanced peak values were achieved when using the protocols with 80 kV tube voltage than 120 kV.By using a low dose protocol of 80 kV tube voltage with the iterative reconstruction algorithm,the quality of image can be warranted.
