Interpretability of coronary CT angiography performed with a novel whole-heart coverage high-definition CT scanner in 300 consecutive patients with coronary artery bypass grafts

AimsCoronary CT angiography (CCTA) is an accurate non-invasive tool for the evaluation of coronary artery bypass graft (CABG). However, inability to sustain a long breath-hold, high heart rate (HR) and atrial fibrillation may affect image quality. Moreover, radiation exposure is still a matter of some concern. A scanner combining 0.23-mm spatial resolution, new iterative reconstruction and fast gantry rotation time has been recently introduced in the clinical field. The aims of our study were to evaluate interpretability, radiation exposure and diagnostic accuracy of CCTA performed with the latest generation of cardiac-CT scanners compared to invasive coronary angiography (ICA) in the assessment of bypass grafts, and non-grafted and post-anastomotic native coronary arteries.Methods and resultsWe prospectively enrolled 300 patients undergoing clinically indicated CCTA with a 16-cm z-axis coverage, 256-detector rows, and 0.28-sec gantry rotation time scanner. Coronary artery and graft interpretability, image quality and effective dose (ED) were assessed in all patients and diagnostic accuracy was evaluated in a subgroup of 100 patients who underwent ICA.Mean HR during the scan was 69.6 ± 10.8. Sinus rhythm was present in 118 patients with HR < 75 bpm and in 112 patients with HR ≥ 75 bpm, while 70 patients had atrial fibrillation. CABG interpretability was 100%. Compared to ICA, CCTA was able to correctly detecting occlusions or significant stenoses of all CABG segments. Overall interpretability of native coronary segments was 95.6%. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of coronary arteries were 98.3%, 97.4%, 93.1%, 99.3% and 96.5%, respectively. The diagnostic accuracy in a patient based analysis was 95.2%. Mean ED was 3.14 ± 1.7 mSv.ConclusionsThe novel whole-heart coverage CT scanner allows to evaluating CABG and native coronary arteries with excellent interpretability and low radiation exposure even in the presence of unfavorable heart rhythm.     

An initial randomised study assessing free-breathing CCTA using 320-detector CT

Objectives

To evaluate the feasibility of free-breathing coronary computed tomography angiography (CCTA) in adults using with a 320-detector multidetector CT (MDCT).

Methods

In 74 patients who underwent CCTA, 37 CCTA examinations were performed during free-breathing, and the remaining 37 CCTA examinations were produced with the standard breath-holding method. The quality scores for 16 segments of all coronary arteries were analysed and defined as: 1 (excellent), 2 (good), and 3 (poor). The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and effective radiation dose of each image were compared between the two methods.

Results

No significant differences were observed in the quality scores between the breath-holding and free-breathing methods (1.10?±?0.31 vs. 1.12?±?0.33; P?=?0.443). The SNR and CNR were not significantly different between the two methods. The overall mean effective radiation dose revealed no significant difference between the two methods (P?=?0.585).

Conclusions

Free-breathing CCTA using 320-detector MDCT showed no significant difference in image quality compared with standard breath-holding CCTA. For patients with difficulties of breath-holding or non-negligible apnoea-related heart rate variability, free-breathing CCTA can be an alternative solution for coronary artery evaluation.

Key Points

? Cardiac CT is becoming widely used and some patients are inevitably breathless. ? Multidetector CT (e.g. 320) offers new opportunities for the breathless patient. ? Free breathing images yielded similar image quality to those obtained using breath-holding. ? However, a possibility of higher radiation dose precludes its routine application.     

The value of Coronary Artery computed Tomography as the first-line anatomical test for stable patients with indications for invasive angiography due to suspected Coronary Artery Disease: CAT-CAD randomized trial

BackgroundThe aim of this prospective, randomized trial was to evaluate whether the use of coronary computed tomography angiography (CCTA) as the first-line anatomical test in patients with suspected significant coronary artery disease (CAD) may reduce the number of coronary invasive angiographies (ICA), and expand the use of CCTA in patients currently diagnosed invasively.Methods120 patients (age:60.6 ± 7.9 years, 35% female) with indications to ICA were randomized 1:1 to undergo CCTA versus direct ICA. Outcomes were evaluated during the diagnostic and therapeutic periods.ResultsThe number of invasively examined patients was reduced by 64.4% in the CCTA group as compared to the direct ICA group (21vs59,p < 0.0001). The number of patients with ICAs not followed by coronary intervention was reduced by 88.1% with the CCTA strategy (5vs42,p < 0.0001). Over the diagnostic and therapeutic course there were no significant differences regarding the median volume of contrast (CCTA 80.3 ml[65.0–165.0] vs ICA 90.0 ml[55.0–100.0], p = 0.099), while a non-significant trend towards higher radiation dose in the CCTA group was observed (9.9 mSv[7.0–22.1] vs 9.4 mSv[5.2–14.0], p = 0.05). There were no acute cardiovascular events.ConclusionsCCTA may hypothetically act as an effective ‘gatekeeper’ to the catheterization laboratory in the diagnosis of stable patients with current indications for ICA. This strategy may result in non-invasive, outpatient-based triage of two thirds of individuals without actionable CAD, obviating unnecessary invasive examinations. However, the longer follow-up is indispensable.ClinicalTrials.gov numberNCT02591992     

Performance of turbo high-pitch dual-source CT for coronary CT angiography: first ex vivo and patient experience

Objectives

To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA).

Methods

First, a cardiac motion phantom simulating heart rates (HRs) from 60-90 bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250 ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50 years) undergoing clinically indicated CCTA were included.

Results

In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1 mm or less. Distortion increased above 1 mm at HR of 80-90 bpm. Patients had a mean HR of 66 bpm (47-78 bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73 bpm. Average effective radiation dose in patients was 0.6?±?0.3 mSv.

Conclusions

Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75 bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6 mSv.

Key points

? CCTA is feasible with the turbo high-pitch mode. ? Turbo high-pitch CCTA provides diagnostic image quality up to 73 bpm. ? The radiation dose of high-pitch CCTA is 0.6 mSv on average.     

Image quality and radiation dose of coronary CT angiography performed with whole-heart coverage CT scanner with intra-cycle motion correction algorithm in patients with atrial fibrillation

Objectives

To evaluate image quality, coronary evaluability and radiation exposure of coronary CT angiography (CCTA) performed with whole-heart coverage cardiac-CT in patients with atrial fibrillation (AF).

Materials and methods

We prospectively enrolled 164 patients with AF who underwent a clinically indicated CCTA with a 16-cm z-axis coverage scanner. In all patients CCTA was performed using prospective ECG-triggering with targeted RR interval. We evaluated image quality, coronary evaluability and effective dose (ED). Patients were divided in two subgroups based on heart rate (HR) during imaging. Group 1: 64 patients with low HR (<75 bpm), group 2: 100 patients with high HR (≥75 bpm). Written informed consent was obtained from all patients and the institutional ethics committee approved the study protocol.

Results

In a segment-based analysis, coronary evaluability was 98.4 % (2,577/2,620 segments) in the whole population, without significant differences between groups (1,013/1,024 (98.9 %) and 1,565/1,596 (98.1 %), for groups 1 and 2, respectively, p=0.15). Mean ED was similar in both groups (3.8±1.9 mSv and 3.9±2.1 mSv in groups 1 and 2, respectively, p=0.75)

Conclusions

The whole-heart-coverage scanner could evaluate coronary arteries with high image quality and without increase in radiation exposure in AF patients, even in the high HR group.

Key points

? Last-generation CT scanner improves coronary artery assessment in AF patients. ? The new CT scanner enables low radiation exposure in AF patients. ? Diagnostic ICA maybe avoided in AF patients with suspected CAD. ? Whole-heart coverage CT scanner enables low radiation exposure in AF patients.

     

Feasibility of prospectively ECG-triggered high-pitch coronary CT angiography with 30 mL iodinated contrast agent at 70 kVp: initial experience

Objectives

To evaluate the feasibility, image quality and radiation dose of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) with 30 mL contrast agent at 70 kVp.

Methods

Fifty-eight patients with suspected coronary artery disease, a body mass index (BMI) of less than 25 kg/m², sinus rhythm and a heart rate (HR) of less than 70 beats per minute (bpm) were prospectively enrolled in this study. Thirty mL of 370 mg I/mL iodinated contrast agent was administrated at a flow rate of 5 mL/s. All patients underwent prospectively ECG-triggered high-pitch CCTA on a second-generation dual-source CT system at 70 kVp using automated tube current modulation.

Results

Fifty-six patients (96.6 %) had diagnostic CCTA images and two patients (3.4 %) had one vessel with poor image quality each rated as non-diagnostic. No significant effects of HR, HR variability and BMI on CCTA image quality were observed (all P?>?0.05). Effective dose was 0.17?±?0.02 mSv and the size-specific dose estimate was 1.03?±?0.13 mGy.

Conclusion

Prospectively ECG-triggered high-pitch CCTA at 70 kVp with 30 mL of contrast agent can provide diagnostic image quality at a radiation dose of less than 0.2 mSv in patients with a BMI of less than 25 kg/m² and an HR of less than 70 bpm.

Key points

? Prospectively ECG-triggered high-pitch CCTA at 70 kVp/30 mL contrast agent is feasible. ? Diagnostic image quality can be obtained at a radiation dose of less than 0.2 mSv. ? This protocol is suitable for normal-weight patients with slow heart rate.     

Adequate image quality with reduced radiation dose in prospectively triggered coronary CTA compared with retrospective techniques

The goal of our study was to compare a prospective triggering (PT) CT technique with retrospectively gated (RG) CT techniques in coronary computed tomographic angiograms (CCTA) with respect to image quality and radiation dose. Sixty consecutive patients were enrolled. CCTAs using the RG technique were obtained with a dual-source 64-slice CT system in 40 patients, using ECG-triggered tube current modulation, with either a broad pulsing window at 30–80% of the RR interval (group RGb, 20 patients, heart rate > 70 bpm) or a small pulsing window at 70% (group RGs, 20 patients, heart rate < 70 bpm). The other 20 patients underwent CCTA using the PT technique on a 128-slice CT system (group PT, heart rate < 70 bpm). All images were evaluated by two observers for quality on a three-point scale, with 1 being excellent and 3 being insufficient. The effective radiation dose was calculated for each patient. The average image quality score was 1.5 ± 0.6 for PT, 1.35 ± 0.5 for RGs and 1.65 ± 0.5 for RGb. The mean effective dose for RGb was 9 ± 4 mSv, for RGs 7 ± 3 mSv and for PT 3 ± 1 mSv. This represents a 57% dose reduction for PT compared with RGs and a 67% dose reduction for PT compared with RGb. In conclusion, in selected patients CCTA with the PT technique offers adequate image quality with a significantly lower radiation dose compared with CCTA using RG techniques. None of the authors have financial or other kinds of interests that might pose a conflict of interest in connection with this article.     

Diagnostic accuracy of dual-source CT coronary angiography with prospective ECG-triggering on different heart rate patients

Objective

To evaluate the diagnostic accuracy of dual-source CT (DSCT) prospective ECG-triggering coronary angiography in patients with different heart rate (HR).

Methods

103 patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography (ICA). The patients were grouped by HR during CT scans: low HR (??60?bpm, n?=?34); medium HR (60?n?=?36) and high HR (>70?bpm, n?=?33). The sensitivity and specificity of DSCT in detecting ??50% stenosis were compared among subgroups where ICA was the gold standard. Image quality was scored using a 4-point scale.

Results

A total of 1,580 (95.9%) coronary artery segments were evaluable. Sensitivity and specificity were 82.8% and 98.4%, 88.3% and 98.7%, and 80.3% and 98.6% for different subgroups (all p?>?0.05). The overall area under the curve of the receiver-operating characteristic analysis was 0.94. The image quality scores were 3.1?±?0.3, 3.1?±?0.3 and 3.0?±?0.4 for subgroups (p?>?0.05). The overall average effective radiation dose was 3.60?±?1.60?mSv.

Conclusion

DSCT coronary angiography with prospective ECG-triggering could be just as accurate in patients with medium to high HR compared to those with low HR.     

256层螺旋CT低剂量冠状动脉成像研究

目的：评价256层CT前瞻性心电门控冠状动脉成像的图像质量与辐射剂量,并与回顾性心电门控对照分析。方法 共200例患者纳入研究。100例行前瞻性心电门控的患者分为2组：(1)心率≤70次/min( bpm )50例,数据采集时间窗设在心动周期的75％期相（A组）;(2)心率＞70 bpm 50例,数据采集时间窗设在心动周期的45％期相,包含5％宽容度（B组）。另外100例行回顾性心电门控的患者亦分为2组：(3)心率≤70 bpm 50例,最大管电流输出设在75％期相（C组）;(4)心率＞ 70 bpm 50例,最大管电流输出设在45％与75％期相（D组）。所有患者由数字表法随机分组。采用4分法半定量分析冠状动脉节段及整体评分。采用Mann-Whitney U检验比较组间图像质量,采用t检验比较组间的辐射剂量;并对100例前瞻性心电门控检查者冠状动脉图像质量与平均心率进行ROC分析及相关分析。结果 在共2338个冠状动脉节段中,图像质量优秀或良好（评分1或2分）者A组中达到96.5％( 585/606),B组为77.7％(445/573),C组为96.1％( 548/570),D组为85.7％ (505/589),冠状动脉节段图像质量A组与C组比较差异无统计学意义（Z＝ -1.351,P＞0.05）;B组和D组差异有统计学意义（Z＝-2.236,P＜0.05）。前瞻性心电门控检查ROC分析及相关分析显示,平均心率与冠状动脉图像质量密切相关(r＝0.577,P＜0.01),平均心率78 bpm可做为满足诊断图像的最高临界点心率（ROC曲线下面积为0.827,P＜0.05）。A组[(2.6±0.5)mSv]相对C组[(10.6 ±2.3) mSy]平均辐射剂量减少75％,B组[(4.0 ±0.7) mSy]相对D组[ (13.0±1.4) mSy]平均辐射剂量减少69％。结论 256层CT低剂量前瞻性心电门控成像可获得与回顾性心电门控相似的满足诊断需要的图像质量,并可应用于高心率检查者。     

Validation of deep-learning image reconstruction for coronary computed tomography angiography: Impact on noise,image quality and diagnostic accuracy

BackgroundAdvances in image reconstruction are necessary to decrease radiation exposure from coronary CT angiography (CCTA) further, but iterative reconstruction has been shown to degrade image quality at high levels. Deep-learning image reconstruction (DLIR) offers unique opportunities to overcome these limitations. The present study compared the impact of DLIR and adaptive statistical iterative reconstruction-Veo (ASiR-V) on quantitative and qualitative image parameters and the diagnostic accuracy of CCTA using invasive coronary angiography (ICA) as the standard of reference.MethodsThis retrospective study includes 43 patients who underwent clinically indicated CCTA and ICA. Datasets were reconstructed with ASiR-V 70% (using standard [SD] and high-definition [HD] kernels) and with DLIR at different levels (i.e., medium [M] and high [H]). Image noise, image quality, and coronary luminal narrowing were evaluated by three blinded readers. Diagnostic accuracy was compared against ICA.ResultsNoise did not significantly differ between ASiR-V SD and DLIR-M (37 vs. 37 HU, p = 1.000), but was significantly lower in DLIR-H (30 HU, p < 0.001) and higher in ASiR-V HD (53 HU, p < 0.001). Image quality was higher for DLIR-M and DLIR-H (3.4–3.8 and 4.2–4.6) compared to ASiR-V SD and HD (2.1–2.7 and 1.8–2.2; p < 0.001), with DLIR-H yielding the highest image quality. Consistently across readers, no significant differences in sensitivity (88% vs. 92%; p = 0.453), specificity (73% vs. 73%; p = 0.583) and diagnostic accuracy (80% vs. 82%; p = 0.366) were found between ASiR-V HD and DLIR-H.ConclusionDLIR significantly reduces noise in CCTA compared to ASiR-V, while yielding superior image quality at equal diagnostic accuracy.     

Accuracy of dual-source CT coronary angiography: first experience in a high pre-test probability population without heart rate control

The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1±11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14±9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter ≥1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3±3.9 kg/m² (range 22.4–36.3 kg/m²), mean heart rate during CT was 70.3±14.2 bpm (range 47–102 bpm), and mean Agatston score was 821±904 (range 0–3,110). Image quality was diagnostic (scores 1–3) in 98.6% (414/420) of segments (mean image quality score 1.68±0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control.     

Assessing the value of coronary artery computed tomography as the first-line anatomical test for stable patients with indications for invasive angiography due to suspected coronary artery disease. Initial cost analysis in the CAT-CAD randomized trial

BackgroundClinical and safety outcomes of the strategy employing coronary computed tomography angiography (CCTA) as the first-choice imaging test have recently been demonstrated in the recently published CAT-CAD randomized, prospective, single-center study. Based on prospectively collected data in this patient population, we aimed to perform an initial cost analysis of this approach.Methods120 participants of the CAT-CAD trial (age:60.6 ± 7.9 years, 35% female) were included in the analysis. We analyzed medical resource use during the diagnostic and therapeutic episode of care. We prospectively estimated the cumulative cost for each strategy by multiplying the number of resources by standardized costs in accordance to medical databases and the 2015 Procedural Reimbursement Payment Guide.ResultsThe total cost of coronary artery disease (CAD) diagnosis was significantly lower in the CCTA group as compared to the direct invasive coronary angiography (ICA) group ($50,176 vs $137,032) with corresponding per-patient cost of $836 vs $2,284, respectively. Similarly, the entire diagnostic and therapeutic episode of care was significantly less expensive in the CCTA group ($227,622 vs $502,827) with corresponding per-patient cost of $4630 vs $8,380, respectively. Overall, the application of CCTA as a first-line diagnostic test in stable patients with indications to ICA resulted in a 63% reduction of CAD diagnosis costs and a 55% reduction composite of diagnosis and treatment costs during 90-days follow-up.ConclusionsApplication of CCTA as the first-line anatomic test in patients with suspected significant CAD decreased the total costs of diagnosis. This is likely attributable to reduced numbers of invasive tests and hospitalisations. Initial cost analysis of the CAT-CAD randomized trial suggests that this approach may provide significant cost savings for the entire health system.     

320层容积CT超低剂量扫描在冠状动脉成像中的应用

目的 评价320层CT冠状动脉成像中前瞻性轴面容积扫描不同kV设置对辐射剂量及图像质量的影响,探讨＜1 mSv冠状动脉检查的可行性及应用价值.方法 从拟行冠状动脉成像的患者中连续选取80例,随机分成A、B两组各40例,A组扫描时管电压为100 kV,B组为120 kV.A组经AIDR软件重建后成为A1组.比较A、B两组升主动脉根部平均强化CT值(SI)、噪声(SD)、信噪比(SNR)、对比信噪比(CNR)、有效辐射剂量(E)及图像质量评分.分别比较A、A1和B、A1组间患者SI、SD、SNR、CNR及图像质量评分.结果 A组有效辐射剂量为(0.67±0.18) mSv,B组为(3.08±1.04)mSv(t=- 14.30,P＜0.05),平均减少了78％.A、B两组的图像质量评分分别为(4.57±0.57)和(4.59±0.59)分(t=-1.17,P＞0.05).A、B组SI、SD、SNR、CNR分别为(570.8±131.5)HU、25.1±6.9、24.5±9.1、19.8±6.1和(460.6±14.3)HU、15.1±3.6、31.7±7.7、29.3±6.8.两组SI、SD比较,A组大于B组,差异有统计学意义(t=4.49、8.18,P＜0.05);SNR、CNR A组小于B组,差异有统计学意义(t=-4.24、-6.19,P＜0.05).A1组SI、SD、SNR、CNR、图像质量评分(557.9±24.5)HU、21.1±6.0、27.7±10.0、23.4±7.8、(4.60±0.56)分,与A组相比,SI、图像质量评分差异无统计学意义(t =1.09、-1.90,P＞0.05);SD、SNR、CNR差异有统计学意义(t=-5.97、-4.18、-6.22,P＜0.05).结论 320层CT冠状动脉成像前瞻性轴面容积扫描中,采用100 kV管电压扫描,其辐射剂量可降到1mSv以下,并且图像质量达到诊断要求.     

双源CT前瞻性心电门控对较高心率患者冠状动脉成像的准确性研究

目的 评价双源CT(DSCT)前瞻性心电门控对较高心率(HR)冠状动脉成像图像质量及诊断冠心病(CAD)的准确性.方法 回顾性分析103例连续患者的有创冠状动脉造影(ICA)和DSCT前瞻性心电门控冠状动脉成像资料,根据患者DSCT扫描时的心率分成3组,低心率组[<60次/min(bpm)]34例、中等心率组(60-70 bpm)36例和较高心率组(HR>70 bpm)33例.分析各组DSCT冠状动脉成像的图像质量(1～4分),以ICA为金标准,评价不同心率下DSCT前瞻性心电门控诊断CAD(狭窄≥50%)的敏感度和特异度,差异性用x2检验.结果 共1648个冠状动脉节段中的1580个(95.9%)能够满足诊断的图像质量要求,低、中、较高心率3组图像质量评分分别为(3.1±0.3)、(3.1±0.3)和(3.0±0.4)分(x2=2.80,P>0.05).各组诊断CAD的敏感度、特异度分别为82.8%(77/93)和98.4%(428/435),88.3%(91/103)和98.7%(442/448),80.3%(57/71)和98.6%(424/430)(x2值分别为0.69和0.13,P值均>0.05).总体ROC曲线下面积为0.94(95%可信区间为0.92～0.96),平均有效辐射剂量为(3.60±1.60)mSv.结论 DSCT前瞻性心电门控能够用于较高心率患者的冠状动脉成像,与较低心率组在诊断CAD时差异无统计学意义.

Abstract：

Objective To evaluate the diagnostic accuracy of dual-source CT(DSCT)prospective ECG-triggering coronary angiography in patients with different heart rate(HR).Methods One hundred and three patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography(ICA).The patients were grouped by HR during CT scans:low HR(<60 bpm,n=34),medium HR(60-70 bpm,n=36)and high HR(>70 bpm,n=33).Image quality was scored using a 4-point scale.The sensitivity and specificity of DSCT in detecting≥50%stenosis were compared among subgroups where ICA was the gold standard.The differences were compared by using the X2 test of contingency on a per-segment and per-vessel basis.Results Image quality of 1580 coronary artery segments in 1648(95.9%)met the requirements for diagnosis.The image quality scores were(3.1±0.3),(3.1±0.3)and(3.0±0.4)point for subgroups(X2=2.80,P>0.05).Sensitivity and specificity were 82.8%(77/93)and 98.4%(428/435),88.3%(91/103)and 98.7%(442/448),and 80.3%(57/71)and 98.6%(424/430)for different subgroups(X2 were 0.69 and 0.13,all P>0.05).The overall area under the receiver operating characteristic(ROC)curve was 0.94(95%CI=0.92-0.96).The average effective radiation dose was(3.60±1.60)mSv.Conclusion DSCT coronary angiography with prospective ECG-triggering could be used for patients with high HR.And the diagnostic accuracy was not statistical significant between the patients with low HR and patients with medium to high HR.     

Feasibility of coronary CT angiography for guidance of CABG

ObjectiveTo assess the clinical safety and effectiveness of coronary revascularization in patients who underwent coronary artery bypass grafting (CABG) based exclusively on coronary computed tomography angiography (CCTA) results.Methods53 patients (62.3 ± 7.1 years) underwent CCTA before a CABG surgery without prior invasive coronary angiography (ICA). Primary endpoints were all-cause mortality and major adverse cardiovascular events (MACE). The secondary endpoint was quality of life (QoL) assessed with the Minnesota Living with Heart Failure Questionnaire (MLHFQ). All were collected one year after the surgery.ResultsCCTA revealed multivessel coronary artery disease (CAD) in 52 patients. Indication for bypass surgery was made exclusively based on CCTA results. 136 distal anastomoses were performed. Assessment at 1 year (13.3 ± 1.4 months) was completed in 98.1% of the patients. MACE and mortality rates were 0%. The MLHFQ total score was 21.8 ± 8.7, and active lifestyle was maintained in all patients.ConclusionsIn this proof of concept prospective pilot study, we observed that non-invasive coronary angiography may provide adequate anatomic detail to guide CABG surgery. Further study of this concept is warranted.     

Diagnostic accuracy of high-pitch dual-source CT for the assessment of coronary stenoses: first experience

Objectives

The objective was to prospectively investigate the diagnostic accuracy of high-pitch (HP) dual-source computed tomography coronary angiography (CTCA) compared with catheter coronary angiography (CCA) for the diagnosis of significant coronary stenoses.

Methods

Thirty-five patients (seven women; mean age 62?±?8 years) underwent both CTCA and CCA. CTCA was performed with a second-generation dual-source CT system permitting data acquisition at an HP of 3.4. Patients with heart rates >60 bpm were excluded from study enrolment. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a four-point scale (1: excellent to 4: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). CCA served as the standard of reference. Radiation dose values were calculated using the dose-length product.

Results

Diagnostic image quality was found in 99% of all segments (455/459). Non-diagnostic image quality occurred in a single patient with a sudden increase in heart rate immediately before and during CTCA. Taking segments with non-evaluative image quality as positive for disease, the sensitivity, specificity and positive and negative predictive values were 94, 96, 80 and 99% per segment and 100, 91, 88 and 100% per patient. The effective radiation dose was on average 0.9?±?0.1 mSv.

Conclusion

In patients with heart rates ≤60 bpm, CTCA using the HP mode of the dual-source CT system is associated with high diagnostic accuracy for the assessment of coronary artery stenoses at sub-milliSievert doses.     

64-Slice spiral computed tomography of the coronary arteries: dose reduction using an optimized imaging protocol including individual weight-adaptation of voltage and current–time product

Radiation dose and image quality were compared between a standard protocol (40 patients, group A) and a weight-adapted protocol of voltage and current–time product (44 patients, group B) using 64-slice coronary multidetector computed tomography (MDCT). Effective dose estimate was lower by 37% in all patients of group B (9.2 ± 2.5 mSv) compared with group A (14.6 ± 2.3 mSv, P < 0.0001). Group B patients with a small body mass index (BMI) benefited most with a dose reduction of 53% (6.7 ± 1.5 mSv in group B versus 14.1 ± 1.8 mSv in group A, P < 0.0001). Moderate reductions of 32% and 20% were achieved for patients with a medium and large BMI, respectively. Reduction in radiation dose did not affect the image quality as assessed by image noise, signal-to-noise ratios, and number of coronary segments with good diagnostic image quality. Individual weight-adaptation of voltage and current–time product significantly reduces the radiation dose without loss of image quality.     

Image quality of ultra-low-dose dual-source CT angiography using high-pitch spiral acquisition and iterative reconstruction in young children with congenital heart disease

BackgroundObtaining diagnostic CT image quality with ultra-low radiation dose in young children with congenital heart disease remains challenging.ObjectiveWe evaluated the feasibility and image quality of prospectively electrocardiogram (ECG)-triggered high-pitch spiral acquisition with iterative reconstruction for pediatric cardiovascular CT angiography.MethodsSixty-two consecutive pediatric patients younger than 2 years with congenital heart disease underwent prospectively ECG-triggered high-pitch spiral dual-source CT acquisition. Patients were randomly assigned into 2 groups: full tube current (40–70 mAs) scans with filtered back projection reconstruction (group A) and half tube current (20–35 mAs) scans with sinogram-affirmed iterative reconstruction (group B). Attenuation, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality were compared between the 2 groups. Effective radiation dose was also estimated for both groups.ResultsNo significant difference was found in the attenuation, image noise, SNR, and CNR between the 2 groups in the same evaluated anatomic regions, whereas the attenuation and image noise were slightly lower, and the SNR and CNR were slightly higher in group B. No significant difference was found in subjective image quality between the 2 groups (4.27 ± 0.73 vs. 4.34 ± 0.42; P = .813). Effective dose was 0.06 ± 0.03 mSv in group B and 0.13 ± 0.04 mSv in group A, reflecting dose savings of 53.8% by using iterative reconstruction.ConclusionsA combination of prospectively ECG-triggered high-pitch spiral acquisition, low tube current, and iterative reconstruction may offer diagnostic image quality in pediatric cardiovascular CT angiography with effective radiation dose < 0.1 mSv.     

Prospectively ECG-triggered sequential dual-source coronary CT angiography in patients with atrial fibrillation: comparison with retrospectively ECG-gated helical CT

Objective

To investigate the feasibility of applying prospectively ECG-triggered sequential coronary CT angiography (CCTA) to patients with atrial fibrillation (AF) and evaluate the image quality and radiation dose compared with a retrospectively ECG-gated helical protocol.

Methods

100 patients with persistent AF were enrolled. Fifty patients were randomly assigned to a prospective protocol and the other patients to a retrospective protocol using a second-generation dual-source CT (DS-CT). Image quality was evaluated using a four-point grading scale (1 = excellent, 2 = good, 3 = moderate, 4 = poor) by two reviewers on a per-segment basis. The coronary artery segments were considered non-diagnostic with a quality score of 4. The radiation dose was evaluated.

Results

Diagnostic segment rate in the prospective group was 99.4 % (642/646 segments), while that in the retrospective group was 96.5 % (604/626 segments) (P?<?0.001). Effective dose was 4.29?±?1.86 and 11.95?±?5.34 mSv for each of the two protocols (P?<?0.001), which was a 64 % reduction in the radiation dose for prospective sequential imaging compared with retrospective helical imaging.

Conclusion

In AF patients, prospectively ECG-triggered sequential CCTA is feasible using second-generation DS-CT and can decrease >60 % radiation exposure compared with retrospectively ECG-gated helical imaging while improving diagnostic image quality.

Key Points

? Coronary computed tomographic angiography (CCTA) can be difficult in patients with arrhythmias. ? Prospectively ECG-triggered sequential CCTA is feasible in patients with atrial fibrillation. ? Prospective sequential imaging can improve quality compared with retrospective analysis. ? Prospective sequential imaging decreases radiation exposure by 64 % compared with retrospective mode.     

CT angiography for planning transcatheter aortic valve replacement using automated tube voltage selection: Image quality and radiation exposure

PurposeTo assess image quality and accuracy of CT angiography (CTA) for transcatheter aortic valve replacement (TAVR) planning performed with 3rd generation dual-source CT (DSCT).Material and methodsWe evaluated 125 patients who underwent TAVR-planning CTA on 3rd generation DSCT. A two-part protocol was performed including retrospectively ECG-gated coronary CTA (CCTA) and prospectively ECG-triggered aortoiliac CTA using 60 mL of contrast medium. Automated tube voltage selection and advanced iterative reconstruction were applied. Effective dose (ED), signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated. Five-point scales were used for subjective image quality analysis. In patients who underwent TAVR, sizing parameters were obtained.ResultsImage quality was rated good to excellent in 97.6% of CCTA and 100% of aortoiliac CTAs. CTA studies at >100 kV showed decreased objective image quality compared to 70–100 kV (SNR, all p ≤ 0.0459; CNR, all p ≤ 0.0462). Mean ED increased continuously from 70 to >100 kV (CCTA: 4.5 ± 1.7 mSv–13.6 ± 2.9 mSv, all p ≤ 0.0233; aortoiliac CTA: 2.4 ± 0.9 mSv–6.8 ± 2.7 mSv, all p ≤ 0.0414). In 39 patients TAVR was performed and annulus diameter was within the recommended range in all patients. No severe cardiac or vascular complications were noted.Conclusion3rd generation DSCT provides diagnostic image quality in TAVR-planning CTA and facilitates reliable assessment of TAVR device and delivery option while reducing radiation dose.