低剂量CT在小儿冠状动脉疾病诊断中的应用
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摘要
目的：与经胸壁超声心动图(transthoracic echocardiography, TTE)对比研究,评价双源CT低剂量扫描在小儿川崎病冠状动脉损害诊断中的价值。
方法：本研究前瞻性纳入47例临床诊断为川崎病冠状动脉损害的患儿,最终入选45例。所有患儿同时行TTE和双源CT低剂量扫描,两种检查间隔时间为1-9天。其中,男28例,女17例；平均年龄为11个月(范围2月-63月),平均体重为12.8kg(范围5.8-28kg)；平均心率112次／分(bpm)(范围87-146bpm)；平均发热时间约38天(范围13-196天)。所有纳入对象均表现为持续发热、口腔黏膜充血,眼结膜充血,躯干部皮疹,15例患者表现为草莓舌,20例患者表现为指／趾端脱皮。所有患者均符合川崎病的临床诊断标准。冠状动脉按照13段分段法,由2名经验丰富的放射科医师在双盲的情况下独立阅片,图像质量的主观评分按照5分法进行：1=图像质量优秀,无运动伪影；2=轻度伪影或一个阶梯样伪影；3=≥2个阶梯样伪影或轻度血管搏动伪影；4=重度血管搏动伪影,评价受限；5=冠状动脉节段无法识别。川崎病的危险分级按照2004年美国心脏协会(American Heart Association, AHA)发表的关于川崎病诊断、治疗及长期管理的声明(5级危险分层)为准。Cohen's k-test评价2名放射科医师对川崎病冠状动脉瘤样扩张／动脉瘤数量、位置、长径、直径及危险分级的诊断一致性；Bland-Altman分析法评价TTE与低剂量CT的诊断一致性。记录所有患儿的辐射剂量参数：CTDIvol,DLP,并计算有效辐射剂量(Effective Dose,ED)。
结果：45例临床疑诊川崎病患者均成功完成冠状动脉CT低剂量成像和TTE成像,并获得可诊断图像；CT低剂量扫描的可诊断冠状动脉节段比例为90.94%(532/585),TTE可诊断节段比例为29.91%(175/585)。
1.CT低剂量冠状动脉成像结果：
2名观察者对冠状动脉节段的评分分别为(2.12-0.7)分和(2.07±0.5)分,平均分为2.10±0.8；2名评价者对冠状动脉的主观图像的评分具有较高的诊断一致性(k=0.85)。可诊断冠状动脉节段为90.94%(532/585)；2名评价者对血管长径及直径测量值具有较好的一致性(长径k=0.83,直径k=0.87)。
其中,29例患者被低剂量CT诊断为小儿川崎病冠状动脉瘤样扩张(n=10)／动脉瘤(n=98)／血管扩张(n=17)。28例均被诊断为川崎病危险分层第Ⅳ级,1例诊断为川崎病危险分层第Ⅴ级。10个动脉瘤和4个血管扩张内可见血栓形成；2例患者合并冠状动脉钙化,1例患者见单支冠状动脉闭塞。
2.超声检查血诊断结果
29例患者被超声心动图诊断为川崎病冠状动脉损害。超声共检出4个瘤样扩张,52个动脉瘤和11血管扩张。其中,8个动脉瘤和4个血管扩张内可见血栓形成；2例患者见钙化,未见冠状动脉狭窄病例。26例被诊断为川崎病危险分层第Ⅳ级,3例被诊断为川崎病冠状动脉损害危险分层第Ⅲ级。
3.低剂量CT与TTE的诊断一致性
对于低剂量CT与TTE共同显示的4个瘤样扩张,52个动脉瘤和11血管扩张,两种检查方法对病变的位置及大小评价结果一致性好。CT低剂量测得的平均直径为(0.74±0.32)cm,TTE测得的平均直径为(0.74±0.29)cm；Bland-Altman测得的二者偏移为2.3%,一致性的上、下限值分别为33.8%,-27.5%。低剂量CT测得的长径平均值为(2.07±1.31)cm,TTE测得的平均值为(2.01±1.31)cm；Bland-A1tman测得的二者偏移为-2.0%,一致性的上、下限值分别为25.3%,-21.6%。TTE与低剂量CT在血管长径、直径方面具有很好的一致性。
4.辐射剂量
45例患者的平均CTDIvol为(0.95±0.22)mGy,平均DLP为(10.0±2.72) mGy*cm。平均有效辐射剂量为(0.59±0.23)mSv,范围为(0.36-1.17)mSv。
结论：冠状动脉低剂量CT扫描对小儿川崎病冠状动脉损害尤其是远段冠状动脉病变的显示率较高,可以作为川崎病危险分级的主要诊断依据。
目的：本研究旨在讨论：1)小儿冠状动脉CTA的70kV低电压扫描方案的参数设定；2)以传统血管造影／手术为金标准,比较70kV与80kV扫描方案的图像质量及辐射剂量。
方法：本研究前瞻性纳入81例临床疑诊冠状动脉病变(川崎病冠状动脉损害／先天性心脏病合并冠状动脉畸形)的患儿资料,最终入选78例,男46例,女32例；平均年龄为38个月(范围9天-72月),平均体重为12.2kg(范围3.6-31kg)；平均心率92次／分(bpm)(范围77-146bpm)。所有患儿均行前瞻性心电门控序列扫描；根据扫描方案不同分为3组,A组：n=26,管电压80kV,对比剂用量1.5ml/kg体重,管电流按照体重调整,<5kg,50-69mAs；5-10kg,70-89mAs；10-15kg,90-109mAs；15-20kg,110-129mAs；≥20kg,130-160mAs；B组：n=26,管电压70kV,对比剂用量1.5ml/kg,管电流按照体重调整,参照A组,同体重组患者,管电流提高20mAs；C组：n=26,管电压70kV,对比剂用量1ml/kg体重,其余同B组。比较三组患者的个体参数(包括：年龄、体重、性别、心率)及扫描时间、扫描范围。由2名放射科医师采用双盲法独立阅片,以4分法评价总体图像质量(3：优秀；2：良好；1：可诊断；0：差),测量所有患者升主动脉根部的CT值、图像噪声、信噪比及对比度噪声比。同时记录CTDIvol和DLP值,计算患儿接受的有效辐射剂量(ED,mSv)。与手术和／或造影结果为诊断标准,计算三种扫描方案对小儿先天性冠状动脉病变的诊断准确性。
结果：78例患儿均成功完成冠状动脉CTA检查。各组间患者的年龄、性别、体重、心率、扫描时间及扫描范围等差异均无统计学意义。A组共检出冠状动脉-心腔瘘3例,左冠状动脉起源肺动脉2例,冠状动脉起源变异3例,川崎病冠状动脉损害8例,冠状动脉肺动脉瘘2例,单支冠状动脉2例,无冠状动脉畸形／病变6例；B组共检出冠状动脉-心腔瘘2例,左冠状动脉起源肺动脉2例,川崎病冠状动脉损害8例,冠状动脉肺动脉瘘1例,单支冠状动脉1例,冠状动脉起源变异3例,无冠状动脉畸形／病变9例；C组共检出冠状动脉-心腔瘘3例,冠状动脉肺动脉瘘1例,左冠状动脉起源于肺动脉3例,单支冠状动脉1例,冠状动脉起源变异2例,川崎病冠状动脉损害10例,无冠状动脉畸形／病变6例。以手术和/或造影结果为诊断标准,A,B,C三组对冠状动脉病变的诊断准确率均为100%。2名放射科医师的诊断一致性较好(kappa=0.82,0.84,0.85)。2名放射科医师对三组患儿的主观图像质量平均评分分别为2.2±0.6,2.1±0.5,2.4±0.4,组间及组内差异均无统计学意义。
80kV组(A组)与70kV组(B+C组)的CTDIvol分别为(0.98±0.23)mGy,(0.57±0.16)mGy,差异有统计学意义(t=7.55,p=0.00),DLP分别为(10.3±2.76)mGy*cm,(6.21±1.93)mGy*cm,差异有统计学意义(t=5.31,p=0.00),有效辐射剂量分别为(0.60±0.24)mSv,(0.39±0.10)mSv,有效辐射降低了35.0%,差异有显著统计学意义(t=3.40,p=0.005)。
结论：双源CT前瞻性心电门控心血管成像70kV低电压结合低对比剂用量(1.0ml/kg)能够较好的显示冠状动脉,与手术和/或造影对比,具有较高的诊断准确性；与(80kV+1.5ml/kg)及(70kV+1.5ml/kg)扫描方案组比较,信噪比及对比度噪声比增加,且显著降低了辐射剂量及对比剂用量。70kV低电压结合低对比剂用量CT冠状动脉成像是一种准确诊断小儿心脏大血管畸形的检查方法。
Objective:To prospectively evaluate the application of low dose CT coronary angiography in the diagnosis of children with coronary arterial lesions due to Kawasaki disease (KD) in comparison with transthoracic echocardiography (TTE).
Materials and Methods:Forty-seven children with suspected coronary arterial lesions due to Kawasaki disease were prospectively enrolled, and a total of45patients could be included in this study. All patients underwent low-dose CT coronary arterial angiography and TTE with interval about1-9days. There were28males and17females, mean age11months (age range2months to63months), mean body weight12.8kg (range from5.8kg to28kg), mean heart rates112bpm (range from87bpm to146bpm), mean fever time38days (range from13days to196days). Persistent and unexplained fever was found in all cases, bilateral non-suppurative conjunctivitis, inflammation of the mucosa in the lip and mouth were found in all cases, strawberry-tone were founded in15cases, changes in the extremities appeared in20cases. All of the patients meet the diagnostic standard of KD.The visualization capability of coronary arteries was graded for13arterial segments.Subjective image quality was independently assessed by2radiologists with several years of experience in reading coronary artery angiographic images. Overall image quality was assessed using a5-point grading scale(1=no motion artifact;2=minimal motion artifact, one stair-step artifact;3=moderate motion artifact,≥2stair-step artifacts or minimal blurring of a vessel;4=severe artifact, assessment was limited by blurring of vessel;5=the vessel was not recognisable). The risk-level category (risk level Ⅰ-Ⅴ) was evaluated by the statement about diagnosis, treatment and long-term management of KD from American Heart Association (AHA) in2004. Inter-observer agreement in subjective image quality grading and CT measurements was assessed by Cohen's k-test. Bland-Altman analysis was used to evaluate the agreement on measurements of aneurysms between CT angiographic images and TTE. The average radiation dose parameters (CTDIvol, DLP, effective dose) were calculated for all children.
Results:All low dose CT angiography and TTE examinations were performed successfully, and the image quality was sufficient for data analysis in all cases. The diagnostic coronary arterial segments ratio was90.94%(532/585)for CT angiography, and29.91%(175/585)for TTE.
1.Low dose CT coronary artery angiographic findings
The mean score of2observers for coronary artery segments was2.12±0.7and2.07±0.5,respectively. And mean score of the2observers was2.10±0.8.The inter-observer agreement for subjective image quality was excellent (kappa=0.85). Diagnostic image quality was present in90.94%(532/585)of the segments.The CT measurements showed excellent inter-observer agreements (diameter:k=0.83;length: k=0.87).
Twenty-nine cases out of45patients were diagnosed with Kawasaki disease by CT angiography.A total of10dilations,98aneurysms and17arterial ectasias were detected by low dose CT angiography. Twenty-eight cases were classified as risk level IV and1case was classified as risk level V by low dose CT. Thrombosis was found in10aneurysms and4ectasias;Calcification was founded in2cases; and stenosis was detected in one patient by DSCTCA.
2.Echocardiography findings
Twenty-nine cases out of45patients were diagnosed with Kawasaki disease by TTE. A total of4dilations,52aneurysms and11arterial ectasias were found by TTE. Thrombosis was found in8aneurysms and4ectasias. Calcification was founded in2cases; and no stenosis was detected by TTE.26cases were classified as risk level IV and3cases were classified as level Ⅲby TTE.
3.Assessment of Agreement between Low dose CT and TTE
For all the4dilations,52aneurysms and11ectasias detected by both low dose CT and TTE, the described location and size were consistent with each other. Mean aneurysms diameter with CT was (0.74±0.32) cm and with TTE was (0.74±0.29) cm. Comparison the mean diameters between DSCTCA and TTE yielded a bias of2.3%, a lower limit of agreement of-27.5%, and an upper limit of agreement of33.8%. Mean aneurysms length with CT was (2.07±1.31)cm and with TTE was (2.01±1.31)cm. Comparison the mean lengths between CT and TTE yielded a bias of-2.0%, a lower limit of agreement of-21.6%, and an upper limit of agreement of25.3%.The Bland-Altman plot for agreement between low dose CT and TTE showed good correlation in the diameter and length measurements.
4. Radiation Dose Estimates
The mean CTDIvol, DLP and effective dose of all45patients was (0.95±0.22) mGy,(10.0±2.72) mGy*cm and (0.59±0.23)mSv (range from0.36to1.17mSv), respectively.
Conclusions:Low dose CT with excellent image quality and low radiation exposure has been proved useful in diagnosis and risk stratification for infants and children with coronary artery lesions due to Kawasaki disease, especially for the distal segments.
Purpose:To prospectively compare pediatric CT coronary angiography performed at a low tube voltage of70kV and reduced dose of contrast agent(1.0ml/kg) with standard tube voltage of80kV, standard contrast agent dose(1.5ml/kg) CT angiography in patients with coronary arterial diseases.
Materials and methods:The study has institutional review board approval; written informed consent was obtained.In this prospective study,81consecutive infants or children suspected with coronary arterial diseases (coronary arterial lesions due to Kawasaki diseases or coronary arterial deformities accompanied with congenital heart diseases) were evaluated. All infants and children underwent prospective ECG-triggering DSCT coronary arterial angiography using128-slice DSCT. Patients were divided into3groups by different scanning protocols. Group A (n=26):80kV and1.5ml/kg contrast agent, tube current was tailored by patients'weight:<5kg,50-69mAs;5-10kg,70-89mAs;10-15kg,90-109mAs;15-20kg,110-129mAs;>20kg,130-160mAs; Group B (n=26):70kV and1.5ml/kg contrast agent, tube current was tailored by patients'weight, at the same weight group, the tube current was20mAs more than the group A; Group C (n=26):70kV and1.0ml/kg contrast agent, tube current setting is the same as group B. The patients'age, weight, sex, heart rates, scanning time and scanning range were compared with each group. Two-independent radiologists were invited to evaluate the subjective image quality by4-point grading scale (3=excellent,2=good,1=mediate,0=poor). Vessel enhancement (CT attenuation), image noise (IN), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated for each protocol. Radiation dose (CTDIvol, DLP) was recorded and effective dose was calculated. Compared with conventional cardiac angiography (CCA) or surgical findings, the diagnostic efficiency was evaluated. Results:All low-dose CT angiography were performed successfully, and the image quality was sufficient for data analysis in all cases.There were no significant differences in patients'characteristics (age, weight, sex and heart rates) and scanning time, scanning range.
In group A, the diagnoses at CTA were coronary-cameral fistula (n=3), left coronary artery from the pulmonary artery (ALCAPA, n=2), anomalies of coronary artery (n=3),coronary arterial lesions due to Kawasaki disease (n=8), coronary-pulmonary fistula (n=2), single coronary artery (n=2), no coronary arterial disease (n=6). In group B, the diagnoses at CTA were coronary-cameral fistula (n=2), left coronary artery from the pulmonary artery (ALCAPA, n=2), coronary arterial lesions due to Kawasaki disease (n=8), coronary-pulmonary fistula (n=1),single coronary artery (n=1),anomalies of coronary artery (n=3), no coronary arterial disease (n=9).In group C, the diagnoses at CTA were coronary-cameral fistula (n=3), coronary-pulmonary fistula(n=1),left coronary artery from the pulmonary artery (ALCAPA, n=3),anomalies of coronary artery (n=2), single coronary artery (n=1), coronary arterial lesions due to Kawasaki disease (n=10), no coronary arterial disease (n=6). Compared with surgical/conventional coronary angiographic findings, all of the coronary arterial diseases were confirmed, and the accuracy of CTA with different protocol was100%.The mean score of subjective image quality was2.2±0.6,2.1±0.5and2.4±0.4, respectively. There was no significant difference in visual scores for subjective image quality among3protocols and within groups (all p>0.05).
The CTDIvol of80kV-and70kV-protocol was (0.98±0.23)mGy,(0.57±0.16) mGy,there was significant differences among protocols (t=7.55, p=0.00), the DLP of80kV-and70kV-protocol was(10.3±2.76) mGy*cm,(6.21±1.93)mGy*cm, there was significant differences among protocols (t=5.31,p=0.00), the effective dose of80kV-and70kV-protocol was (0.60±0.24) mSv,(0.39±0.10) mSv, there was significant differences among protocols (t=3.40,p=0.005;-35.0%). Conclusion:At a low tube voltage and a reduced dose of contrast agent, the protocol of70-kV and1ml/kg contrast agent is a feasible and accurate option for128-slice DSCT coronary angiography in pediatric patients with coronary arterial diseases.
方法：本研究前瞻性纳入47例临床诊断为川崎病冠状动脉损害的患儿,最终入选45例。所有患儿同时行TTE和双源CT低剂量扫描,两种检查间隔时间为1-9天。其中,男28例,女17例；平均年龄为11个月(范围2月-63月),平均体重为12.8kg(范围5.8-28kg)；平均心率112次／分(bpm)(范围87-146bpm)；平均发热时间约38天(范围13-196天)。所有纳入对象均表现为持续发热、口腔黏膜充血,眼结膜充血,躯干部皮疹,15例患者表现为草莓舌,20例患者表现为指／趾端脱皮。所有患者均符合川崎病的临床诊断标准。冠状动脉按照13段分段法,由2名经验丰富的放射科医师在双盲的情况下独立阅片,图像质量的主观评分按照5分法进行：1=图像质量优秀,无运动伪影；2=轻度伪影或一个阶梯样伪影；3=≥2个阶梯样伪影或轻度血管搏动伪影；4=重度血管搏动伪影,评价受限；5=冠状动脉节段无法识别。川崎病的危险分级按照2004年美国心脏协会(American Heart Association, AHA)发表的关于川崎病诊断、治疗及长期管理的声明(5级危险分层)为准。Cohen's k-test评价2名放射科医师对川崎病冠状动脉瘤样扩张／动脉瘤数量、位置、长径、直径及危险分级的诊断一致性；Bland-Altman分析法评价TTE与低剂量CT的诊断一致性。记录所有患儿的辐射剂量参数：CTDIvol,DLP,并计算有效辐射剂量(Effective Dose,ED)。
结果：45例临床疑诊川崎病患者均成功完成冠状动脉CT低剂量成像和TTE成像,并获得可诊断图像；CT低剂量扫描的可诊断冠状动脉节段比例为90.94%(532/585),TTE可诊断节段比例为29.91%(175/585)。
1.CT低剂量冠状动脉成像结果：
2名观察者对冠状动脉节段的评分分别为(2.12-0.7)分和(2.07±0.5)分,平均分为2.10±0.8；2名评价者对冠状动脉的主观图像的评分具有较高的诊断一致性(k=0.85)。可诊断冠状动脉节段为90.94%(532/585)；2名评价者对血管长径及直径测量值具有较好的一致性(长径k=0.83,直径k=0.87)。
其中,29例患者被低剂量CT诊断为小儿川崎病冠状动脉瘤样扩张(n=10)／动脉瘤(n=98)／血管扩张(n=17)。28例均被诊断为川崎病危险分层第Ⅳ级,1例诊断为川崎病危险分层第Ⅴ级。10个动脉瘤和4个血管扩张内可见血栓形成；2例患者合并冠状动脉钙化,1例患者见单支冠状动脉闭塞。
2.超声检查血诊断结果
29例患者被超声心动图诊断为川崎病冠状动脉损害。超声共检出4个瘤样扩张,52个动脉瘤和11血管扩张。其中,8个动脉瘤和4个血管扩张内可见血栓形成；2例患者见钙化,未见冠状动脉狭窄病例。26例被诊断为川崎病危险分层第Ⅳ级,3例被诊断为川崎病冠状动脉损害危险分层第Ⅲ级。
3.低剂量CT与TTE的诊断一致性
对于低剂量CT与TTE共同显示的4个瘤样扩张,52个动脉瘤和11血管扩张,两种检查方法对病变的位置及大小评价结果一致性好。CT低剂量测得的平均直径为(0.74±0.32)cm,TTE测得的平均直径为(0.74±0.29)cm；Bland-Altman测得的二者偏移为2.3%,一致性的上、下限值分别为33.8%,-27.5%。低剂量CT测得的长径平均值为(2.07±1.31)cm,TTE测得的平均值为(2.01±1.31)cm；Bland-A1tman测得的二者偏移为-2.0%,一致性的上、下限值分别为25.3%,-21.6%。TTE与低剂量CT在血管长径、直径方面具有很好的一致性。
4.辐射剂量
45例患者的平均CTDIvol为(0.95±0.22)mGy,平均DLP为(10.0±2.72) mGy*cm。平均有效辐射剂量为(0.59±0.23)mSv,范围为(0.36-1.17)mSv。
结论：冠状动脉低剂量CT扫描对小儿川崎病冠状动脉损害尤其是远段冠状动脉病变的显示率较高,可以作为川崎病危险分级的主要诊断依据。
目的：本研究旨在讨论：1)小儿冠状动脉CTA的70kV低电压扫描方案的参数设定；2)以传统血管造影／手术为金标准,比较70kV与80kV扫描方案的图像质量及辐射剂量。
方法：本研究前瞻性纳入81例临床疑诊冠状动脉病变(川崎病冠状动脉损害／先天性心脏病合并冠状动脉畸形)的患儿资料,最终入选78例,男46例,女32例；平均年龄为38个月(范围9天-72月),平均体重为12.2kg(范围3.6-31kg)；平均心率92次／分(bpm)(范围77-146bpm)。所有患儿均行前瞻性心电门控序列扫描；根据扫描方案不同分为3组,A组：n=26,管电压80kV,对比剂用量1.5ml/kg体重,管电流按照体重调整,<5kg,50-69mAs；5-10kg,70-89mAs；10-15kg,90-109mAs；15-20kg,110-129mAs；≥20kg,130-160mAs；B组：n=26,管电压70kV,对比剂用量1.5ml/kg,管电流按照体重调整,参照A组,同体重组患者,管电流提高20mAs；C组：n=26,管电压70kV,对比剂用量1ml/kg体重,其余同B组。比较三组患者的个体参数(包括：年龄、体重、性别、心率)及扫描时间、扫描范围。由2名放射科医师采用双盲法独立阅片,以4分法评价总体图像质量(3：优秀；2：良好；1：可诊断；0：差),测量所有患者升主动脉根部的CT值、图像噪声、信噪比及对比度噪声比。同时记录CTDIvol和DLP值,计算患儿接受的有效辐射剂量(ED,mSv)。与手术和／或造影结果为诊断标准,计算三种扫描方案对小儿先天性冠状动脉病变的诊断准确性。
结果：78例患儿均成功完成冠状动脉CTA检查。各组间患者的年龄、性别、体重、心率、扫描时间及扫描范围等差异均无统计学意义。A组共检出冠状动脉-心腔瘘3例,左冠状动脉起源肺动脉2例,冠状动脉起源变异3例,川崎病冠状动脉损害8例,冠状动脉肺动脉瘘2例,单支冠状动脉2例,无冠状动脉畸形／病变6例；B组共检出冠状动脉-心腔瘘2例,左冠状动脉起源肺动脉2例,川崎病冠状动脉损害8例,冠状动脉肺动脉瘘1例,单支冠状动脉1例,冠状动脉起源变异3例,无冠状动脉畸形／病变9例；C组共检出冠状动脉-心腔瘘3例,冠状动脉肺动脉瘘1例,左冠状动脉起源于肺动脉3例,单支冠状动脉1例,冠状动脉起源变异2例,川崎病冠状动脉损害10例,无冠状动脉畸形／病变6例。以手术和/或造影结果为诊断标准,A,B,C三组对冠状动脉病变的诊断准确率均为100%。2名放射科医师的诊断一致性较好(kappa=0.82,0.84,0.85)。2名放射科医师对三组患儿的主观图像质量平均评分分别为2.2±0.6,2.1±0.5,2.4±0.4,组间及组内差异均无统计学意义。
80kV组(A组)与70kV组(B+C组)的CTDIvol分别为(0.98±0.23)mGy,(0.57±0.16)mGy,差异有统计学意义(t=7.55,p=0.00),DLP分别为(10.3±2.76)mGy*cm,(6.21±1.93)mGy*cm,差异有统计学意义(t=5.31,p=0.00),有效辐射剂量分别为(0.60±0.24)mSv,(0.39±0.10)mSv,有效辐射降低了35.0%,差异有显著统计学意义(t=3.40,p=0.005)。
结论：双源CT前瞻性心电门控心血管成像70kV低电压结合低对比剂用量(1.0ml/kg)能够较好的显示冠状动脉,与手术和/或造影对比,具有较高的诊断准确性；与(80kV+1.5ml/kg)及(70kV+1.5ml/kg)扫描方案组比较,信噪比及对比度噪声比增加,且显著降低了辐射剂量及对比剂用量。70kV低电压结合低对比剂用量CT冠状动脉成像是一种准确诊断小儿心脏大血管畸形的检查方法。
Objective:To prospectively evaluate the application of low dose CT coronary angiography in the diagnosis of children with coronary arterial lesions due to Kawasaki disease (KD) in comparison with transthoracic echocardiography (TTE).
Materials and Methods:Forty-seven children with suspected coronary arterial lesions due to Kawasaki disease were prospectively enrolled, and a total of45patients could be included in this study. All patients underwent low-dose CT coronary arterial angiography and TTE with interval about1-9days. There were28males and17females, mean age11months (age range2months to63months), mean body weight12.8kg (range from5.8kg to28kg), mean heart rates112bpm (range from87bpm to146bpm), mean fever time38days (range from13days to196days). Persistent and unexplained fever was found in all cases, bilateral non-suppurative conjunctivitis, inflammation of the mucosa in the lip and mouth were found in all cases, strawberry-tone were founded in15cases, changes in the extremities appeared in20cases. All of the patients meet the diagnostic standard of KD.The visualization capability of coronary arteries was graded for13arterial segments.Subjective image quality was independently assessed by2radiologists with several years of experience in reading coronary artery angiographic images. Overall image quality was assessed using a5-point grading scale(1=no motion artifact;2=minimal motion artifact, one stair-step artifact;3=moderate motion artifact,≥2stair-step artifacts or minimal blurring of a vessel;4=severe artifact, assessment was limited by blurring of vessel;5=the vessel was not recognisable). The risk-level category (risk level Ⅰ-Ⅴ) was evaluated by the statement about diagnosis, treatment and long-term management of KD from American Heart Association (AHA) in2004. Inter-observer agreement in subjective image quality grading and CT measurements was assessed by Cohen's k-test. Bland-Altman analysis was used to evaluate the agreement on measurements of aneurysms between CT angiographic images and TTE. The average radiation dose parameters (CTDIvol, DLP, effective dose) were calculated for all children.
Results:All low dose CT angiography and TTE examinations were performed successfully, and the image quality was sufficient for data analysis in all cases. The diagnostic coronary arterial segments ratio was90.94%(532/585)for CT angiography, and29.91%(175/585)for TTE.
1.Low dose CT coronary artery angiographic findings
The mean score of2observers for coronary artery segments was2.12±0.7and2.07±0.5,respectively. And mean score of the2observers was2.10±0.8.The inter-observer agreement for subjective image quality was excellent (kappa=0.85). Diagnostic image quality was present in90.94%(532/585)of the segments.The CT measurements showed excellent inter-observer agreements (diameter:k=0.83;length: k=0.87).
Twenty-nine cases out of45patients were diagnosed with Kawasaki disease by CT angiography.A total of10dilations,98aneurysms and17arterial ectasias were detected by low dose CT angiography. Twenty-eight cases were classified as risk level IV and1case was classified as risk level V by low dose CT. Thrombosis was found in10aneurysms and4ectasias;Calcification was founded in2cases; and stenosis was detected in one patient by DSCTCA.
2.Echocardiography findings
Twenty-nine cases out of45patients were diagnosed with Kawasaki disease by TTE. A total of4dilations,52aneurysms and11arterial ectasias were found by TTE. Thrombosis was found in8aneurysms and4ectasias. Calcification was founded in2cases; and no stenosis was detected by TTE.26cases were classified as risk level IV and3cases were classified as level Ⅲby TTE.
3.Assessment of Agreement between Low dose CT and TTE
For all the4dilations,52aneurysms and11ectasias detected by both low dose CT and TTE, the described location and size were consistent with each other. Mean aneurysms diameter with CT was (0.74±0.32) cm and with TTE was (0.74±0.29) cm. Comparison the mean diameters between DSCTCA and TTE yielded a bias of2.3%, a lower limit of agreement of-27.5%, and an upper limit of agreement of33.8%. Mean aneurysms length with CT was (2.07±1.31)cm and with TTE was (2.01±1.31)cm. Comparison the mean lengths between CT and TTE yielded a bias of-2.0%, a lower limit of agreement of-21.6%, and an upper limit of agreement of25.3%.The Bland-Altman plot for agreement between low dose CT and TTE showed good correlation in the diameter and length measurements.
4. Radiation Dose Estimates
The mean CTDIvol, DLP and effective dose of all45patients was (0.95±0.22) mGy,(10.0±2.72) mGy*cm and (0.59±0.23)mSv (range from0.36to1.17mSv), respectively.
Conclusions:Low dose CT with excellent image quality and low radiation exposure has been proved useful in diagnosis and risk stratification for infants and children with coronary artery lesions due to Kawasaki disease, especially for the distal segments.
Purpose:To prospectively compare pediatric CT coronary angiography performed at a low tube voltage of70kV and reduced dose of contrast agent(1.0ml/kg) with standard tube voltage of80kV, standard contrast agent dose(1.5ml/kg) CT angiography in patients with coronary arterial diseases.
Materials and methods:The study has institutional review board approval; written informed consent was obtained.In this prospective study,81consecutive infants or children suspected with coronary arterial diseases (coronary arterial lesions due to Kawasaki diseases or coronary arterial deformities accompanied with congenital heart diseases) were evaluated. All infants and children underwent prospective ECG-triggering DSCT coronary arterial angiography using128-slice DSCT. Patients were divided into3groups by different scanning protocols. Group A (n=26):80kV and1.5ml/kg contrast agent, tube current was tailored by patients'weight:<5kg,50-69mAs;5-10kg,70-89mAs;10-15kg,90-109mAs;15-20kg,110-129mAs;>20kg,130-160mAs; Group B (n=26):70kV and1.5ml/kg contrast agent, tube current was tailored by patients'weight, at the same weight group, the tube current was20mAs more than the group A; Group C (n=26):70kV and1.0ml/kg contrast agent, tube current setting is the same as group B. The patients'age, weight, sex, heart rates, scanning time and scanning range were compared with each group. Two-independent radiologists were invited to evaluate the subjective image quality by4-point grading scale (3=excellent,2=good,1=mediate,0=poor). Vessel enhancement (CT attenuation), image noise (IN), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated for each protocol. Radiation dose (CTDIvol, DLP) was recorded and effective dose was calculated. Compared with conventional cardiac angiography (CCA) or surgical findings, the diagnostic efficiency was evaluated. Results:All low-dose CT angiography were performed successfully, and the image quality was sufficient for data analysis in all cases.There were no significant differences in patients'characteristics (age, weight, sex and heart rates) and scanning time, scanning range.
In group A, the diagnoses at CTA were coronary-cameral fistula (n=3), left coronary artery from the pulmonary artery (ALCAPA, n=2), anomalies of coronary artery (n=3),coronary arterial lesions due to Kawasaki disease (n=8), coronary-pulmonary fistula (n=2), single coronary artery (n=2), no coronary arterial disease (n=6). In group B, the diagnoses at CTA were coronary-cameral fistula (n=2), left coronary artery from the pulmonary artery (ALCAPA, n=2), coronary arterial lesions due to Kawasaki disease (n=8), coronary-pulmonary fistula (n=1),single coronary artery (n=1),anomalies of coronary artery (n=3), no coronary arterial disease (n=9).In group C, the diagnoses at CTA were coronary-cameral fistula (n=3), coronary-pulmonary fistula(n=1),left coronary artery from the pulmonary artery (ALCAPA, n=3),anomalies of coronary artery (n=2), single coronary artery (n=1), coronary arterial lesions due to Kawasaki disease (n=10), no coronary arterial disease (n=6). Compared with surgical/conventional coronary angiographic findings, all of the coronary arterial diseases were confirmed, and the accuracy of CTA with different protocol was100%.The mean score of subjective image quality was2.2±0.6,2.1±0.5and2.4±0.4, respectively. There was no significant difference in visual scores for subjective image quality among3protocols and within groups (all p>0.05).
The CTDIvol of80kV-and70kV-protocol was (0.98±0.23)mGy,(0.57±0.16) mGy,there was significant differences among protocols (t=7.55, p=0.00), the DLP of80kV-and70kV-protocol was(10.3±2.76) mGy*cm,(6.21±1.93)mGy*cm, there was significant differences among protocols (t=5.31,p=0.00), the effective dose of80kV-and70kV-protocol was (0.60±0.24) mSv,(0.39±0.10) mSv, there was significant differences among protocols (t=3.40,p=0.005;-35.0%). Conclusion:At a low tube voltage and a reduced dose of contrast agent, the protocol of70-kV and1ml/kg contrast agent is a feasible and accurate option for128-slice DSCT coronary angiography in pediatric patients with coronary arterial diseases.
引文
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