Feasibility of prospectively ECG-triggered high-pitch coronary CT angiography with 30 mL iodinated contrast agent at 70 kVp: initial experience. Eur Radiol. 2014;24:1537-1546. [PMID: 24737530 DOI: 10.1007/s00330-014-3157-2]

Cardiovascular Imaging in China: Yesterday, Today, and Tomorrow

The high prevalence and mortality of cardiovascular diseases in China's large population has increased the use of cardiovascular imaging for the assessment of conditions in recent years. In this study, we review the past 20 years of cardiovascular imaging in China, the increasingly important role played by cardiovascular computed tomography in coronary artery disease and pulmonary embolism assessment, magnetic resonance imaging's use for cardiomyopathy assessment, the development and application of artificial intelligence in cardiovascular imaging, and the future of Chinese cardiovascular imaging.

Update for the Performance of CT Coronary Angiography

BACKGROUND

 Coronary CT angiography (cCTA) is a class 1 recommendation in the current guidelines by the European Society of Cardiology (ESC) for excluding significant coronary artery stenosis. To achieve optimal image quality at a low radiation dose, the imaging physician may choose different acquisition modes. Therefore, the consensus guidelines by the Society of Cardiovascular Computed Tomography (SCCT) provide helpful guidance for this procedure.

METHOD

 The article provides practical recommendations for the application and acquisition of cCTA based on the current literature and our own experience.

RESULTS AND CONCLUSION

 According to current ESC guidelines, cCTA is recommended in symptomatic patients with a low or intermediate clinical likelihood for coronary artery disease. We recommend premedication with beta blockers and nitrates prior to CT acquisition under certain conditions even with the latest CT scanner generations. The most current CT scanners offer three possible scan modes for cCTA acquisition. Heart rate is the main factor for selecting the scan mode. Other factors may be coronary calcifications and body mass index (BMI).

KEY POINTS

  · CCTA is a valid method to exclude coronary artery disease in patients with a low to intermediate clinical likelihood.. · Even with the latest generation CT scanners, premedication with beta blockers and nitrates can improve image quality at low radiation exposure.. · Current CT scanners usually provide retrospective ECG gating and prospective ECG triggering. Dual-source scanners additionally provide a "high pitch" scan mode to scan the whole heart during one heartbeat, which may also be achieved using single-source scanners with broad detectors in some cases.. · Besides the available scanner technology, the choice of scan mode primarily depends on heart rate and heart rate variability (e. g., arrhythmia)..

CITATION FORMAT

· Soschynski M, Hagar MT, Taron J et al. Update for the Performance of CT Coronary Angiography. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1747-3554.

Evaluation of Low-kVp Low-Volume Iodinated Contrast Protocol for Coronary CT Angiography Using Retrospective ECG Gating

Objective The aim of this study was to evaluate the use of low peak kilovoltage (kVp) low-volume iodinated contrast protocol for performing coronary computed tomography (CT) angiography (CCTA) in patients using retrospective electrocardiogram (ECG) gating.

Materials and Methods Hundred prospective patients undergoing CCTA were studied in two groups, A and B, using 70 kilovoltage (kV) and 120 kV protocols with half and standard intravenous volumes of injected iodinated contrast, respectively. All patients had heart rates less than 100 beats/min and body mass index (BMI) less than 31 kg/m2. Both the groups were evaluated for signal-to-noise (S/N) and contrast-to-noise (C/N) ratios along with radiation dose delivered in millisievert (mSv), and for image quality (IQ), on per patient and per segment basis.

Results Patients with group A showed statistically reduced radiation dose of 1.86 mSv compared with 6.86 mSv in group B patients. Marked reduction in image noise with statistically improved S/N and C/N ratios in all coronary vessels was seen in group A. S/N ratios in group A were 20.25, 18.68, 19.04, 17.41, and 18.69 for aorta, left main, left anterior descending, right coronary, and left circumflex arteries while they were 13.34, 11.12, 10.96, 9.74, and 8.67 in group B patients. C/N ratios were also higher in all vessels in group A patients, that is, 19.48, 19.48, 19.04, 19.48, and 17.68, compared with group B patients, who had 12.43, 10.03, 9.23, 9.57, and 8.23 ratios (p < 0.0001). No significant difference in IQ per patient and per vessel was seen between both the groups.

Discussion Retrospective ECG-gated low-kVp low-volume iodinated contrast protocol provides good diagnostic quality angiograms in patients with BMI up to 31 kg/m2 and with heart rates of less than 100 beats/min with three times reduced radiation dose. The reduced volume of contrast reduces the cost as well as the chance of contrast-induced nephropathy.

Canadian Society of Thoracic Radiology/Canadian Association of Radiologists Best Practice Guidance for Investigation of Acute Pulmonary Embolism, Part 1: Acquisition and Safety Considerations

Acute pulmonary embolism (APE) is a well-recognized cause of circulatory system compromise and even demise which can frequently present a diagnostic challenge for the physician. The diagnostic challenge is primarily due to the frequency of indeterminate presentations as well as several other conditions which can have a similar clinical presentation. This often obliges the physician to establish a firm diagnosis due to the potentially serious outcomes related to this disease. Computed tomography pulmonary angiography (CTPA) has increasingly cemented its role as the primary investigation tool in this clinical context and is widely accepted as the standard of care due to several desired attributes which include great accuracy, accessibility, rapid turn-around time and the ability to suggest an alternate diagnosis when APE is not the culprit. In Part 1 of this guidance document, a series of up-to-date recommendations are provided to the reader pertaining to CTPA protocol optimization (including scan range, radiation and intravenous contrast dose), safety measures including the departure from breast and gonadal shielding, population-specific scenarios (pregnancy and early post-partum) and consideration of alternate diagnostic techniques when clinically deemed appropriate.

Tube Voltage, DNA Double-Strand Breaks, and Image Quality in Coronary CT Angiography

OBJECTIVE

To evaluate the effects of tube voltage on image quality in coronary CT angiography (CCTA), the estimated radiation dose, and DNA double-strand breaks (DSBs) in peripheral blood lymphocytes to optimize the use of CCTA in the era of low radiation doses.

MATERIALS AND METHODS

This study included 240 patients who were divided into 2 groups according to the DNA DSB analysis methods, i.e., immunofluorescence microscopy and flow cytometry. Each group was subdivided into 4 subgroups: those receiving CCTA only with different tube voltages of 120, 100, 80, or 70 kVp. Objective and subjective image quality was evaluated by analysis of variance. Radiation dosages were also recorded and compared.

RESULTS

There was no significant difference in demographic characteristics between the 2 groups and 4 subgroups in each group (all p > 0.05). As tube voltage decreased, both image quality and radiation dose decreased gradually and significantly. After CCTA, γ-H2AX foci and mean fluorescence intensity in the 120-, 100-, 80-, and 70-kVp groups increased by 0.14, 0.09, 0.07, and 0.06 foci per cell and 21.26, 9.13, 8.10, and 7.13 (all p < 0.05), respectively. The increase in the DNA DSB level in the 120-kVp group was higher than those in the other 3 groups (all p < 0.05), while there was no significant difference in the DSBs levels among these latter groups (all p > 0.05).

CONCLUSION

The 100-kVp tube voltage may be optimal for CCTA when weighing DNA DSBs against the estimated radiation dose and image quality, with further reductions in tube voltage being unnecessary for CCTA.

Sinogram-Affirmed Iterative Reconstruction Negatively Impacts the Risk Category Based on Agatston Score: A Study Combining Coronary Calcium Score Measurement and Coronary CT Angiography

Purpose

To assess the impact of sinogram-affirmed iterative reconstruction (SAFIRE) on risk category for coronary artery disease by combining coronary calcium score measurement and coronary CT angiography (CCTA).

Materials and Methods

Eighty-nine patients (64.0% male) older than 18 years (64.4 ± 10.3 years) underwent coronary artery calcium scanning and prospectively ECG-triggered sequential CCTA examination. All raw data acquired in coronary artery calcium scanning were reconstructed by both filtered back projection (FBP) and SAFIRE algorithms with 5 different levels. Objective image quality and calcium quantification were evaluated and compared between FBP and all SAFIRE levels by the Sphericity Assumed test or Greenhouse-Geisser ε correction coefficient. Coronary artery stenosis was assessed in CCTA. Risk categories of all patients and of the patients with coronary artery stenosis in CCTA were compared between FBP and all SAFIRE levels by the Friedman test.

Results

The reconstruction protocol from traditional FBP to SAFIRE 5 was associated with a gradual reduction in CT value and image noise (P < 0.001) but associated with a gradual improvement in the signal-to-noise ratio (P < 0.001). There was a gradual reduction in coronary calcification quantification (Agatston score: from 73.5 in FBP to 38.1 in SAFIRE 5, P < 0.001) from traditional FBP to SAFIRE 5. There was a significant difference for the risk category between FBP and all levels of SAFIRE in all patients (from 3.5 in FBP to 3.2 in SAFIRE 5, P < 0.001) and in the patients with coronary artery stenosis in CCTA (from 4.0 in FBP to 3.6 in SAFIRE 5, P < 0.001).

Conclusions

SAFIRE significantly reduces coronary calcification quantification compared to FBP, resulting in the reduction of risk categories based on the Agatston score. The risk categories of the patients with coronary artery stenosis in CCTA may also decline. Thus, SAFIRE may lead risk categories to underestimate the existence of significant coronary artery stenosis.

Application of Low Tube Voltage, Low-concentration Contrast Agent Using a 320-row CT in Coronary CT Angiography: Evaluation of Image Quality, Radiation Dose and Iodine Intake

The effect of low voltage and low concentration contrast agent on image quality of coronary CT angiography, radiation dose and iodine intake was evaluated. A total of 121 patients with body mass index (BMI) <26 kg/m² and heart rate (HR) <70 beats/min were randomly divided into four groups: group A (n=31, 80 kVp, 270 mgI/mL); group B (n=33, 100 kVp, 270 mgI/mL); group C (n=30, 100 kVp, 320 mgI/mL); group D (n=27, 100 kVp, 400 mgI/mL). The automatic current modulation system and the iterative algorithm for reconstruction were adopted in each group. The CT values and SD values of the aortic root (AR), subcutaneous fat, left coronary artery opening (LCA), and right coronary artery opening (RCA) were measured in all groups, the signal-to-noise ratio (SNR) and contrast noise ratio (CNR) were calculated, and effective radiation dose and iodine intake were recorded. The subjective assessment for image quality was performed by two physicians using a 4-point scale. The results were compared using the one-way ANOVA and rank sum tests. The image quality of the four groups met the clinical diagnostic requirements. The CT values of AR in groups A, B, C, and D were 537.6±71.4, 447.2±81.9, 445.2±64.9 and 518.5±94.9 Hu, respectively, with no significant difference between group A and group D, or between group B and group C, while CT values in groups B and C were significantly lower than those in groups A and D (P<0.05). In groups A, B, C, and D, the LCA SNR values were 22.7±9.1, 23.3±9.1, 23.3±7.7 and 26.6±8.9, and the RCA CNR values were 26.9±9.8, 28.5±11.4, 27.7±8.8 and 32.1±10.6, respectively. The AR visual scores in groups A, B, C and D were 3.8±0.2, 3.9±0.3, 3.9±0.3 and 4.0±0.3, respectively. There were no significant differences in SNR, CNR and visual score among the four groups (P>0.05). The radiation doses in groups A, B, C and D were 2.6±1.4, 3.6±1.8, 4.9±3.5 and 4.9±2.8 mSv, respectively. The radiation dose in group A was significantly less than that in the rest three groups (P<0.05). The iodine intakes in groups A, B, C and D were 14.9±1.5, 15.0±1.5, 17.7±2.0 and 18.1±2.5 g, respectively. There was no significant difference in the intake of iodine between groups C and D, or between groups A and B, while iodine intake in groups A and B were significantly reduced as compared with that in groups C and D (P<0.05). It was concluded that for patients with low BMI and controlled HR, compared to 100 kVp tube voltage combined with multiple concentration contrast agents, 80 kVp combined with 270 mgI/mL contrast agent is enough to ensure the quality of the images, and can reduce the radiation dose significantly, while reducing the amount of iodine intake notably, thus reducing the incidence of adverse reaction.

Low-Dose Radiation Advances in Coronary Computed Tomography Angiography in the Diagnosis of Coronary Artery Disease

Background

Coronary computed tomography angiography (CCTA) is now widely used in the diagnosis of coronary artery disease since it is a rapid, minimally invasive test with a diagnostic accuracy comparable to coronary angiography. However, to meet demands for increasing spatial and temporal resolution, higher x-ray radiation doses are required to circumvent the resulting increase in image noise. Exposure to high doses of ionizing radiation with CT imaging is a major health concern due to the potential risk of radiation-associated malignancy. Given its increasing use, a number of dose saving algorithms have been implemented to CCTA to minimize radiation exposure to “as low as reasonably achievable (ALARA)” without compromising diagnostic image quality.

Objective

The purpose of this review is to outline the most recent advances and current status of dose saving techniques in CCTA.

Method

PubMed, Medline, EMBASE and Scholar databases were searched to identify feasibility studies, clinical trials, and technology guidelines on the technical advances in CT scanner hardware and reconstruction software.

Results

Sub-millisievert (mSv) radiation doses have been reported for CCTA due to a combination of strategies such as prospective electrocardiogram-gating, high-pitch helical acquisition, tube current modulation, tube voltage reduction, heart rate reduction, and the most recent novel adaptive iterative reconstruction algorithms.

Conclusion

Advances in radiation dose reduction without loss of image quality justify the use of CCTA as a non-invasive alternative to coronary catheterization in the diagnosis of coronary artery disease.

Coronary CT Angiography in Challenging Patients: High Heart Rate and Atrial Fibrillation. A Review

Despite several strategies have been developed by different vendors to improve image quality and diagnostic accuracy of coronary CT angiography performed at high heart rate (HR) and HR variability, as in patients with atrial fibrillation (AF), some concerns and small clinical experience characterize these subsets of challenging patients. However, patients with AF have been reported to have higher risk of cardiovascular events and noninvasive evaluation of suspected coronary artery disease in this setting may be of extreme clinical interest. The goal of this review is to provide to the reader an overview on the use of cardiac CT in patients with AF and high HR and to outline the technological improvements recently introduced in the clinical field that may enable to definitively overcome the limitations of cardiac CT in this challenging scenario.

Ultra-low dose one-step CT angiography for coronary, carotid and cerebral arteries using 128-slice dual-source CT: A feasibility study

Atherosclerotic diseases are systemic and patient outcomes depend on comprehensive imaging evaluation. Computed tomography angiography (CTA) is a powerful tool used to assess atherosclerosis. However, the scanning protocol is designed for cardiovascular and cerebrovascular imaging, which require considerations into the radiation dose, contrast agent and image quality. The purpose of the present study was to evaluate ultra-low dose one-step CTA for coronary, carotid and cerebral arteries with a low concentration contrast agent. A total of 78 patients were enrolled and randomly divided into two groups: Group A (n=38) and B (n=40). High-pitch CTA for coronary, carotid and cerebral arteries with a tube voltage of 70 or 80 kVp and 40 ml contrast agent (270 mgI/ml) was performed by a 128-slice dual-source CT scanner for group A. Standard high-pitch CTA with a tube voltage of 100 kVp and 60 ml contrast agent (370 mgI/ml) was conducted for group B. The image quality, radiation dose and amount of contrast agent in group A were evaluated and compared with group B. The dose length product for groups A and B was 62.95±21.54 vs. 160.15±15.13 mGy cm, respectively (t=−23.157, P<0.001). The mean total iodine content was 10.8±0 mg for group A and 22.2±0 mg for group B. In total, 99.4% of the arterial segments could be assessed for the two groups (χ²=0.267, P=0.606). The results revealed that ultra-low dose one-step high-pitch CTA can provide assessable image quality, and minimize the radiation dose and contrast agent.

Coronary CT angiography radiation dose trends: A 10-year analysis to develop institutional diagnostic reference levels

PURPOSE

To develop institutional diagnostic reference levels (IDRL) for coronary CT angiography (CCTA) according to patient size by analyzing radiation dose changes over the past 10 years.

MATERIALS AND METHODS

This IRB approved retrospective investigation analyzed radiation dose data from CCTA between 2007 and 2016 at our institution. Annual trends in radiation dose were described for each scanner type and scanning mode. Radiation levels were analyzed for normorhythmic patients, patients with prior coronary artery bypass grafting (CABG), arrhythmia, and according to patient size and tube voltage. Median, and quartile values for volume CT dose index (CTDIvol), dose-length product (DLP), and size-specific dose estimate (SSDE) were calculated. Wilcoxon rank-sum test and Kruskal Wallis test were performed to assess the significance of quantitative data.

RESULTS

35,375 examinations from 33,317 patients (median age, 58 [50-66] years; male patients, 21,087 [58.7%]) were analyzed. CTDIvol, DLP, and SSDE significantly decreased by 9.0%, 30.8%, and 40.1% (all P < 0.05) for all examinations, respectively. All radiation dose metrics progressively decreased across scanning modes (especially retrospectively ECG-gated spiral and prospectively ECG-triggered high-pitch spiral acquisition mode), but did not significantly change across scanners in the last 6 years. CTDIvol and DLP increased with patient size when water-equivalent diameters were >19 cm for normorhythmic and CABG patients. In arrhythmic patients, CTDIvol increased progressively with water-equivalent diameters across all groups.

CONCLUSION

CCTA radiation dose has progressively decreased in the past decade except in patients with prior CABG and arrhythmia. Size-specific IDRLs may optimize radiation utilization in these patients going forward.

Radiation dose reduction using two orthogonal topograms associated with automatic tube voltage selection for lung CT scanning as compared with a single anteroposterior topogram

OBJECTIVE

To evaluate the effectiveness of two orthogonal topograms on radiation dose and image quality (IQ) associated with topogram-based automatic tube voltage selection (ATVS) for lung CT scanning.

METHODS

Thirty-seven patients were enrolled in this study. At baseline, only an anteroposterior topogram was obtained and at follow-up, both anteroposterior and lateral topograms were performed. ATVS was turned on during all scans. Objective and subjective IQ evaluations were performed and compared; tube voltage and radiation dose of each scan were noted and analyzed.

RESULTS

A significant difference was observed regarding the objective parameters between baseline and follow-up only in image noise and signal-noise ratio (SNR) in the upper one-third of the image (image noise: 7.49 ± 1.08 vs. 9.10 ± 1.13, p < 0.001; SNR: 4.08 ± 0.87 vs. 3.37 ± 0.63, p < 0.001). No differences were found between baseline and follow-up in the subjective assessment of IQ. The radiation dose was significantly lower at follow-up than that at baseline (2.73 ± 0.83 mSv vs. 3.55 ± 1.24 mSv, respectively; p < 0.001).

CONCLUSIONS

Using two orthogonal topograms associated with ATVS could significantly reduce the total radiation dose for lung CT scanning, while subjective IQ was maintained.

Periprocedural Concerns in the Patient with Renal Disease

Treating patients with kidney disease can be both a difficult and a complex process. Understanding how to care for patients who have kidney disease is essential for lowering perioperative as well as periprocedural morbidity and mortality. The primary aim in renal evaluation and care is to control and mitigate factors that may result in acute kidney injury (AKI) and/or cause further decline in renal function. It is essential for the foot and ankle specialist to recognize patients who are predisposed to developing or already have impairment of renal function.

Reducing both radiation and contrast doses in coronary CT angiography in lean patients on a 16-cm wide-detector CT using 70 kVp and ASiR-V algorithm, in comparison with the conventional 100-kVp protocol

OBJECTIVE

To investigate the value of prospectively ECG-triggered coronary CT angiography (CCTA) for lean patients with body mass index (BMI) ≤ 23 kg/m² using 70 kVp and high-level volume-based adaptive statistical iterative reconstruction (ASiR-V) algorithm on a 16-cm wide-detector CT system for reducing both radiation and contrast doses in comparison with the conventional 100-kVp protocol.

MATERIALS AND METHODS

Thirty patients (group A) were prospectively enrolled to undergo 70-kVp CCTA on a 16-cm wide-detector CT scanner with noise index (NI) of 36 HU and at weight-dependent contrast dose rate of 16 mg I/kg/s for 9-s injection. Images were reconstructed with 80% ASiR-V. Radiation dose, contrast dose, and image quality were statistically compared with 30 patients (group B) in database with matching BMI who underwent conventional 100-kVp CCTA with NI of 25 HU, and at 25 mg I/kg/s rate for 10-s injection and reconstructed with 60% ASiR-V.

RESULTS

There was no significant difference in patient demographics between the two groups (all p > 0.05). The two groups also had similar mean CT values and contrast-noise ratio (CNR) and subjective image quality (all p > 0.05). However, group A with 70 kVp reduced the effective dose by 75.3% compared with group B (0.43 ± 0.20 mSv vs. 1.74 ± 1.01 mSv, p < 0.001), and required 42.4% less contrast dose than group B (22.46 ± 2.94 ml vs. 38.99 ± 5.10 ml, p < 0.001).

CONCLUSIONS

Prospectively ECG-triggered CCTA using 70 kVp and high-level ASiR-V on a 16-cm wide-detector CT system provides diagnostic images with substantial reduction in both radiation and contrast doses for patients with BMI ≤ 23 kg/m² compared to the conventional 100-kVp protocol.

KEY POINTS

• 70-kVp CCTA produces excellent images at sub-millisievert radiation. • 70-kVp CCTA reduces both radiation and contrast doses over conventional protocol. • Achieving low-dose CCTA with combined low kVp and high-level ASIR-V.

Ultra-low-dose CT coronary angiography using 128-slice dual source CT with low concentration contrast agent: initial experience

PURPOSE

To optimize and evaluate an ultra-low-dose (ULD) technique for CT coronary angiography (CTCA).

MATERIALS AND METHODS

Eighty-two patients were randomly divided into two groups. ULD and routine CTCA were performed in groups A and B. Image quality, radiation dose and contrast agent were evaluated.

RESULTS

The effective dose (ED) was 0.20 ± 0.01 mSv for the ULD technique, a decrease of 87% (t = - 21.182, P < 0.001) compared with the control group. The total iodine content was 8.10 ± 0 g, a decrease of 62% (t = - 73.458, P < 0.001) compared with 21.10 ± 1.15 g for the control group. The assessment rates for both groups were the same (99.26 vs 99.64%, χ ²  = 0.727, P = 0.394). The contrast-to-noise ratio was 19.31 ± 7.95 for group A and 20.73 ± 5.07 for group B: the difference was not statistically significant (t = - 1.678, P = 0.095).

CONCLUSION

Using an ultra-low radiation dose and contrast agent technique, while maintaining an assessable image and improving the safety of the medical examination, was a feasible and reliable method for CTCA.

High-Pitch Coronary CT Angiography at 70 kVp Adopting a Protocol of Low Injection Speed and Low Volume of Contrast Medium

Objective

To evaluate the feasibility and image quality (IQ) of prospectively high-pitch coronary CT angiography (CCTA) with low contrast medium injection rate at 70 kVp.

Materials and Methods

One hundred and four patients with suspected coronary artery disease (body mass index < 26 kg/m², sinus rhythm and heart rate < 70 beats/min) were prospectively enrolled and randomly divided into two groups. In group A and group B, 28 mL and 40 mL of 370 mgI/mL iodinated contrast media was administrated at a flow rate of 3.5 and 5 mL/s, respectively. CT values, noise, signal-to-noise ratio, contrast-to-noise ratio (CNR) of the proximal segments of coronary arteries and subjective IQ were evaluated.

Results

The CT values and noise in group A were significantly lower than those in group B (434–485 Hounsfield units [HU] vs. 772–851 HU, all p < 0.001; 17.8–22.3 vs. 23.3–26.4, all p < 0.005). The CNRs of the right coronary artery and left main artery showed no statistical difference between the two groups (42.1 ± 13.8 vs. 36.8 ± 16.0, p = 0.074; 38.7 ± 10.6 vs. 38.1 ± 17.0, p = 0.819). No statistical difference was observed between the two groups in IQ scores (3.04 ± 0.75 vs. 3.0 ± 0.79, p = 0.526) and diagnostic ratio (96.1% [50/52] vs. 94.2% [49/52], p = 0.647).

Conclusion

Prospective high-pitch CCTA at 70 kVp with 28 mL of contrast media and injection rate of 3.5 mL/s could provide diagnostic IQ for normal-weight patients with heart rate of < 70 beats/min.

Radiation Safety in Children With Congenital and Acquired Heart Disease: A Scientific Position Statement on Multimodality Dose Optimization From the Image Gently Alliance

There is a need for consensus recommendations for ionizing radiation dose optimization during multimodality medical imaging in children with congenital and acquired heart disease (CAHD). These children often have complex diseases and may be exposed to a relatively high cumulative burden of ionizing radiation from medical imaging procedures, including cardiac computed tomography, nuclear cardiology studies, and fluoroscopically guided diagnostic and interventional catheterization and electrophysiology procedures. Although these imaging procedures are all essential to the care of children with CAHD and have contributed to meaningfully improved outcomes in these patients, exposure to ionizing radiation is associated with potential risks, including an increased lifetime attributable risk of cancer. The goal of these recommendations is to encourage informed imaging to achieve appropriate study quality at the lowest achievable dose. Other strategies to improve care include a patient-centered approach to imaging, emphasizing education and informed decision making and programmatic approaches to ensure appropriate dose monitoring. Looking ahead, there is a need for standardization of dose metrics across imaging modalities, so as to encourage comparative effectiveness studies across the spectrum of CAHD in children.

The Impact of Combining a Low-Tube Voltage Acquisition with Iterative Reconstruction on Total Iodine Dose in Coronary CT Angiography

OBJECTIVES

To assess the impact of combining low-tube voltage acquisition with iterative reconstruction (IR) techniques on the iodine dose in coronary CTA.

METHODS

Three minipigs underwent CCTA to compare a standard of care protocol with two alternative study protocols combining low-tube voltage and low iodine dose with IR. Image quality was evaluated objectively by the CT value, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in the main coronary arteries and aorta and subjectively by expert reading. Statistics were performed by Mann-Whitney U test and Chi-square analysis.

RESULTS

Despite reduced iodine dose, both study protocols maintained CT values, SNR, and CNR compared to the standard of care protocol. Expert readings confirmed these findings; all scans were perceived to be of at least diagnostically acceptable quality on all evaluated parameters allowing image interpretation. No statistical differences were observed (all p values > 0.11), except for streak artifacts (p = 0.02) which were considered to be more severe, although acceptable, with the 80 kVp protocol.

CONCLUSIONS

Reduced tube voltage in combination with IR allows a total iodine dose reduction between 37 and 50%, by using contrast media with low iodine concentrations of 200 and 160 mg I/mL, while maintaining image quality.

Contrast-induced acute kidney injury: A review of practical points

Contrast-induced acute kidney injury (CI-AKI) is one of the most common causes of AKI in clinical practice. CI-AKI has been found to be strongly associated with morbidity and mortality of the patients. Furthermore, CI-AKI may not be always reversible and it may be associated with the development of chronic kidney disease. Pathophysiology of CI-AKI is not exactly understood and there is no consensus on the preventive strategies. CI-AKI is an active research area thus clinicians should be updated periodically about this topic. In this review, we aimed to discuss the indications of contrast-enhanced imaging, types of contrast media and their impact on nephrotoxicity, major pathophysiological mechanisms, risk factors and preventive strategies of CI-AKI and alternative non-contrast-enhanced imaging methods.

Prospectively ECG-triggered high-pitch coronary CT angiography at 70 kVp with 30mL contrast agent: An intraindividual comparison with sequential scanning at 120 kVp with 60mL contrast agent

PURPOSE

To investigate image quality, radiation dose, and diagnostic efficiency of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp with 30mL contrast agent intra-individually compared with routine CCTA protocol.

MATERIALS AND METHODS

One hundred and thirty eight patients with suspected coronary artery disease, body mass index (BMI)≤25kg/m² and heart rate (HR)≤70 beats per minute (bpm) underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp and 30mL contrast agent (protocol A) and prospectively ECG-triggered sequential scanning at 120 kVp and 60mL contrast medium (protocol B). Objective and subjective image quality, radiation doses, and diagnostic accuracy were evaluated and compared between the two protocols.

RESULTS

Higher CT attenuation, higher noise, lower signal-to-noise ratios (SNRs) and lower contrast-to-noise ratios (CNRs) were found in protocol A than in protocol B (P<0.001). However, image quality of protocol A were diagnostic. In patients with BMI<23kg/m² or HR<60bpm, subjective image quality scores of some coronary arteries in protocol A were not significantly different from protocol B (P>0.05). Effective dose in protocol A has reduced by 96.7% compared with protocol B (P<0.001). No significant differences were found for diagnostic accuracy between the two protocols on a per-segment (P=0.513), per-vessel (P=0.317) and per-patient (P=0.125) basis.

CONCLUSIONS

Prospectively ECG-triggered high-pitch CCTA at 70kVp with 30mL contrast agent can reduce radiation dose but maintain image quality and high diagnostic accuracy in a selected, non-obese population.

State-of-the-Art Pulmonary CT Angiography for Acute Pulmonary Embolism

OBJECTIVE

Pulmonary CT angiography (CTA) is the imaging modality of choice in suspected acute pulmonary embolism (PE). Current pulmonary CTA techniques involve ever lower doses of contrast medium and radiation along with advanced postprocessing applications to enhance image quality, diagnostic accuracy, and provide added value in patient management. The objective of this article is to summarize these current developments and discuss the appropriate use of state-of-the-art pulmonary CTA.

CONCLUSION

Pulmonary CTA is well established as a fast and reliable means of excluding or diagnosing PE. Continued developments in CT system hardware and postprocessing techniques will allow incremental reductions in radiation and contrast material requirements while improving image quality. Advances in risk stratification and prognostication from pulmonary CTA examinations should further refine its clinical value while minimizing the potential harm from overutilization and overdiagnosis.

Diagnostic accuracy of coronary CT angiography using 3rd-generation dual-source CT and automated tube voltage selection: Clinical application in a non-obese and obese patient population

PURPOSE

To investigate diagnostic accuracy of 3^rd-generation dual-source CT (DSCT) coronary angiography in obese and non-obese patients.

METHODS

We retrospectively analyzed 76 patients who underwent coronary CT angiography (CCTA) and invasive coronary angiography. Prospectively ECG-triggered acquisition was performed with automated tube voltage selection (ATVS). Patients were dichotomized based on body mass index in groups A (<30 kg/m², n = 37) and B (≥30 kg/m², n = 39) and based on tube voltage in groups C (<120 kV, n = 46) and D (120 kV, n = 30). Coronary arteries were assessed for significant stenoses (≥50 % luminal narrowing) and diagnostic accuracy was calculated.

RESULTS

Per-patient overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 96.9 %, 95.5 %, 93.9 %, 97.7 % and 96.1 %, respectively. Sensitivity and NPV were lower in groups B and D compared to groups A and C, but no statistically significant differences were observed (group A vs. B: sensitivity, 100.0 % vs. 93.3 %, p = 0.9493; NPV, 100 % vs. 95.5 %, p = 0.9812; group C vs. D: sensitivity, 100.0 % vs. 92.3 %, p = 0.8462; NPV, 100.0 % vs. 94.1 %, p = 0.8285).

CONCLUSION

CCTA using 3^rd-generation DSCT and (ATVS) provides high diagnostic accuracy in both non-obese and obese patients.

KEY POINTS

• Coronary CTA provides high diagnostic accuracy in non-obese and obese patients. • Diagnostic accuracy between obese and non-obese patients showed no significant difference. • <120 kV studies were performed in 44 % of obese patients. • Current radiation dose-saving approaches can be applied independent of body habitus.

Low contrast medium-volume third-generation dual-source computed tomography angiography for transcatheter aortic valve replacement planning

PURPOSE

To investigate feasibility, image quality and safety of low-tube-voltage, low-contrast-volume comprehensive cardiac and aortoiliac CT angiography (CTA) for planning transcatheter aortic valve replacement (TAVR).

MATERIALS AND METHODS

Forty consecutive TAVR candidates prospectively underwent combined CTA of the aortic root and vascular access route (270 mgI/ml iodixanol). Patients were assigned to group A (second-generation dual-source CT [DSCT], 100 kV, 60 ml contrast, 4.0 ml/s flow rate) or group B (third-generation DSCT, 70 kV, 40 ml contrast, 2.5 ml/s flow rate). Vascular attenuation, noise, signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were compared. Subjective image quality was assessed by two observers. Estimated glomerular filtration (eGFR) at CTA and follow-up were measured.

RESULTS

Besides a higher body-mass-index in group B (24.8±3.8 kg/m² vs. 28.1±5.4 kg/m², P=0.0339), patient characteristics between groups were similar (P≥0.0922). Aortoiliac SNR (P=0.0003) was higher in group B. Cardiac SNR (P=0.0003) and CNR (P=0.0181) were higher in group A. Subjective image quality was similar (P≥0.213) except for aortoiliac image noise (4.42 vs. 4.12, P=0.0374). TAVR-planning measurements were successfully obtained in all patients. There were no significant changes in eGFR among and between groups during follow-up (P≥0.302).

CONCLUSION

TAVR candidates can be safely and effectively evaluated by a comprehensive CTA protocol with low contrast volume using low-tube-voltage acquisition.

KEY POINTS

• Third-generation dual-source CT facilitates low-tube-voltage acquisition. • TAVR planning can be performed with reduced contrast volume and radiation dose. • TAVR-planning CT did not result in changes in creatinine levels at follow-up. • TAVR candidates can be safely evaluated by comprehensive low-tube-voltage CT angiography.

Improved sensitivity of computed tomography towards iodine and gold nanoparticle contrast agents via iterative reconstruction methods

Computed tomography is a widely used medical imaging technique that has high spatial and temporal resolution. Its weakness is its low sensitivity towards contrast media. Iterative reconstruction techniques (ITER) have recently become available, which provide reduced image noise compared with traditional filtered back-projection methods (FBP), which may allow the sensitivity of CT to be improved, however this effect has not been studied in detail. We scanned phantoms containing either an iodine contrast agent or gold nanoparticles. We used a range of tube voltages and currents. We performed reconstruction with FBP, ITER and a novel, iterative, modal-based reconstruction (IMR) algorithm. We found that noise decreased in an algorithm dependent manner (FBP > ITER > IMR) for every scan and that no differences were observed in attenuation rates of the agents. The contrast to noise ratio (CNR) of iodine was highest at 80 kV, whilst the CNR for gold was highest at 140 kV. The CNR of IMR images was almost tenfold higher than that of FBP images. Similar trends were found in dual energy images formed using these algorithms. In conclusion, IMR-based reconstruction techniques will allow contrast agents to be detected with greater sensitivity, and may allow lower contrast agent doses to be used.

Recent developments in the use of computed tomography scanners in coronary artery imaging

INTRODUCTION

Within the past decade, substantial evolution of Coronary CT Angiography (CCTA) has affected evaluation and management of coronary artery disease. In particular, technical advancement of hardware technology and image reconstruction of CT scanners have played an important role in this context making it possible to acquire abundant data with excellent temporal and spatial resolution within a shorter scan time. In addition, a concern related to the high radiation exposure in the initial noninvasive coronary artery imaging has triggered improvement in dose reduction techniques.

AREAS COVERED

In this review article, we have focused on recent technological developments in CT scanners and the impact of these developments on CCTA parameters. Expert Commentary: CCTA plays an important role in coronary artery disease management, and technical development of the CT scanners can be expected to address and remedy technical limitations.

CT Angiography for Revascularization of CTO: Crossing the Borders of Diagnosis and Treatment

Coronary computed tomography angiography (CTA) is increasingly used to diagnose and rule out coronary artery disease. Beyond stenosis detection, the ability of CTA to visualize and characterize coronary atherosclerotic plaque, as well as to obtain 3-dimensional coronary vessel trajectories, has generated considerable interest in the context of pre-procedural planning for revascularization of chronic total occlusions (CTOs). Coronary CTA can characterize features that influence the success rate of percutaneous coronary intervention (PCI) for CTOs such as the extent of calcification, vessel tortuosity, stump morphology, presence of multiple occlusions, and lesion length. Single features and combined scoring systems based on CTA may be used to grade the level of difficulty of the CTOs before PCI and have been shown to predict procedural success rates in several trials. In addition, the procedure itself may be facilitated by real-time integration of 3-dimensional CTA data and fluoroscopic images in the catheterization laboratory. Finally, the ability of coronary CTA to assess anatomy, perfusion, and viability in 1 single examination makes it a potential "one stop shop" that predicts not only the likelihood of successful PCI but also the clinical benefit of CTO revascularization. Further research is clearly needed, but many experienced sites have already integrated coronary CTA into the routine planning and guiding of CTO procedures.

Cardiovascular Imaging: The Past and the Future, Perspectives in Computed Tomography and Magnetic Resonance Imaging

Today's noninvasive imaging of the cardiovascular system has revolutionized the approach to various diseases and has substantially affected prognostic information. Cardiovascular magnetic resonance (MR) and computed tomographic (CT) imaging are at center stage of these approaches, although 5 decades ago, these technologies were unheard of. Both modalities had their inception in the 1970s with a primary focus on noncardiovascular applications. The technical development of the various decades, however, substantially pushed the envelope for cardiovascular MR and CT applications. Within the past 10-15 years, MR and CT technologies have pushed each other in cardiac applications; and without the "rival" modality, neither one would likely not have reached its potential today. This view on the history of MR and CT in the field of cardiovascular applications provides insight into the story of success of applications that once have been ideas only but are at prime time today.

Automated tube voltage selection for radiation dose and contrast medium reduction at coronary CT angiography using 3(rd) generation dual-source CT

OBJECTIVES

To investigate the relationship between automated tube voltage selection (ATVS) and body mass index (BMI) and its effect on image quality and radiation dose of coronary CT angiography (CCTA).

METHODS

We evaluated 272 patients who underwent CCTA with 3(rd) generation dual-source CT (DSCT). Prospectively ECG-triggered spiral acquisition was performed with automated tube current selection and advanced iterative reconstruction. Tube voltages were selected by ATVS (70-120 kV). BMI, effective dose (ED), and vascular attenuation in the coronary arteries were recorded. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used for subjective image quality analysis.

RESULTS

Image quality was rated good to excellent in 98.9 % of examinations without significant differences for proximal and distal attenuation (all p ≥ .0516), whereas image noise was rated significantly higher at 70 kV compared to ≥100 kV (all p < .0266). However, no significant differences were observed in SNR or CNR at 70-120 kV (all p ≥ .0829). Mean ED at 70-120 kV was 1.5 ± 1.2 mSv, 2.4 ± 1.5 mSv, 3.6 ± 2.7 mSv, 5.9 ± 4.0 mSv, 7.9 ± 4.2 mSv, and 10.7 ± 4.1 mSv, respectively (all p ≤ .0414). Correlation analysis showed a moderate association between tube voltage and BMI (r = .639).

CONCLUSION

ATVS allows individual tube voltage adaptation for CCTA performed with 3(rd) generation DSCT, resulting in significantly decreased radiation exposure while maintaining image quality.

KEY POINTS

• Automated tube voltage selection allows an individual tube voltage adaption in CCTA. • A tube voltage-based reduction of contrast medium volume is feasible. • Image quality was maintained while radiation exposure was significantly decreased. • A moderate association between tube voltage and body mass index was found.

Contrast-induced nephropathy in CT: incidence, risk factors and strategies for prevention

In the past, a high percentage of hospital-acquired renal failure was attributed to contrast media. That position is now very controversial. Recently, doubts have been raised regarding the real relationship between acute kidney injury and intravenous contrast media administration. Similarly, statements about specific methods of preventing contrast-inducing nephropathy have been challenged. This review article addresses the controversies of incidence, causation, and prevention in an attempt to help the practicing radiologist adopt methods for their own department.

KEY POINTS

• The reported CIN incidence ranges from 2-12 % following contrast-enhanced CT. • Studies without a non-contrast CT control group may overestimate CIN incidence. • Development and application of a comprehensive CIN prevention strategy is recommended.

70-kVp High-pitch Computed Tomography Pulmonary Angiography with 40 mL Contrast Agent: Initial Experience

RATIONALE AND OBJECTIVES

To assess image quality, radiation dose, and diagnostic accuracy of 70-kVp high-pitch computed tomography pulmonary angiography (CTPA) using 40 mL contrast agent and sinogram affirmed iterative reconstruction (SAFIRE) compared to 100-kVp CTPA using 60 mL contrast agent and filtered back projection.

MATERIALS AND METHODS

Eighty patients underwent CTPA at either 70 kVp (group A, n = 40; 3.2 pitch, 40 mL contrast medium, and SAFIRE) or 100 kVp (group B, n = 40; 1.2 pitch, 60 mL contrast medium, and filtered back projection). Signal-to-noise ratio and contrast-to-noise ratio were calculated. Subjective image quality was evaluated using a five-grade scale, and diagnostic accuracy was assessed. Radiation doses were compared.

RESULTS

Computed tomography values, signal-to-noise ratio, and contrast-to-noise ratio of pulmonary arteries were higher in group A compared to group B (all P < 0.001). Subjective image quality showed no difference between the two groups (P = 0.559) with good interobserver agreement (κ = 0.647). No difference was found regarding diagnostic accuracy between the two groups (P > 0.05). The effective dose for group A was lower by 80% compared to group B (P < 0.001).

CONCLUSIONS

70-kVp high-pitch CTPA with reduced contrast media and SAFIRE provides comparable image quality and substantial radiation dose savings compared to a routine CTPA protocol.

Image quality, radiation dose, and diagnostic accuracy of prospectively ECG-triggered high-pitch coronary CT angiography at 70 kVp in a clinical setting: comparison with invasive coronary angiography

PURPOSE

To investigate image quality, radiation dose, and diagnostic performance of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp compared to invasive coronary angiography (ICA) as reference standard.

MATERIALS AND METHODS

Forty-three patients underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp using 30 cc (11 g iodine) contrast medium and ICA. Subjective and objective image quality was evaluated for each CCTA study. CCTA performance for diagnosing ≥50% stenosis was assessed. Results were stratified according to heart rate (HR), body mass index (BMI), Agatston score, and image quality.

RESULTS

At CCTA, 94.3% (500/530) of coronary segments were of diagnostic quality. Using ICA as reference standard, sensitivity and accuracy were 100% and 93.0% on a per-patient basis. Per-vessel and per-segment performances were 92.2% and 89.5%; 79.5% and 88.3%, respectively. No differences were found in diagnostic accuracy between different HR, BMI, and calcification subgroups (all P > 0.05) on a per-patient basis. However, low image quality reduced diagnostic accuracy on a per-patient, per-vessel and per-segment basis (all P < 0.05). The mean effective radiation dose was 0.2 ± 0.0 mSv.

CONCLUSION

Our presented protocol results in an effective radiation dose of 0.2 mSv and high diagnostic accuracy for stenosis detection in a selected, non-obese population.

KEY POINTS

Prospectively ECG-triggered high-pitch CCTA at 70 kVp is feasible. This protocol has a high diagnostic accuracy for stenosis detection. The mean effective radiation dose was 0.2 ± 0.0 mSv. Only 30 cc of contrast material is used in this protocol. Low image quality reduced diagnostic accuracy of CCTA.

Seventy-Peak Kilovoltage High-Pitch Thoracic Aortic CT Angiography without ECG Gating: Evaluation of Image Quality and Radiation Dose

RATIONALE AND OBJECTIVES

To assess the feasibility of 70-kVp high-pitch non-ECG-gated thoracic aortic computed tomography angiography (CTA) with 40-mL contrast agent compared to 100-kVp standard-pitch CTA with 60-mL contrast agent.

MATERIALS AND METHODS

Sixty-seven patients (51 men and 16 women; mean age, 55 ± 14 years) received non-ECG-gated aortic CTA at 70 kVp, high pitch of 3.4, and 40-mL contrast agent (group A, n = 31) or CTA at 100-kVp, pitch of 1.2, and 60-mL contrast agent (group B, n = 36). Iterative reconstruction was used in all patients. For image quality assessment, CTA images were evaluated on a three-point scale and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated and compared. Furthermore, computed tomography (CT) dose index was recorded.

RESULTS

Mean CT values and noise levels were higher in group A compared to group B (all P < .001), whereas SNR and CNR were lower than those in group B (all P < .001). Furthermore, the image quality of the aorta at the level of the diaphragm was lower in group A than that in group B (P < .05). However, image quality was graded as diagnostic in all patients, and motion artifacts of the aortic arch were significantly decreased in group A (P <.05). Interreader agreement was good or excellent for image quality assessment (k = 0.625-0.835). The 70-kVp CTA protocol, which allows dose reduction of 85%, was considered diagnostic in all instances by two readers.

CONCLUSIONS

Our proposed thoracic aortic CTA protocol provides diagnostic information with substantial reduction of both radiation and contrast agent doses compared to standard-pitch CTA at 100 kVp.

Technical prerequisites and imaging protocols for dynamic and dual energy myocardial perfusion imaging

Coronary CT angiography (CCTA) is an established imaging technique used for the non-invasive morphological assessment of coronary artery disease. As in invasive coronary angiography, CCTA anatomical assessment of coronary stenosis does not adequately predict hemodynamic relevance. However, recent technical improvements provide the possibility of CT myocardial perfusion imaging (CTMPI). Two distinct CT techniques are currently available for myocardial perfusion assessment: static CT myocardial perfusion imaging (sCTMPI), with single- or dual-energy modality, and dynamic CT myocardial perfusion imaging (dCTMPI). The combination of CCTA morphological assessment and CTMPI functional evaluation holds promise for achieving a comprehensive assessment of coronary artery anatomy and myocardial perfusion using a single image modality.

Radiation dose and image quality of 70 kVp cerebral CT angiography with optimized sinogram-affirmed iterative reconstruction: comparison with 120 kVp cerebral CT angiography

OBJECTIVES

To evaluate radiation dose, image quality, and optimal level of sinogram-affirmed iterative reconstruction (SAFIRE) of cerebral CT angiography (CTA) at 70 kVp.

METHODS

One hundred patients were prospectively classified into two groups: Group A (n = 50), 70 kVp cerebral CTA with 5 levels of SAFIRE reconstruction (S1-S5); and Group B (n = 50), 120 kVp with filtered back projection (FBP) reconstruction. CT attenuation values, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the internal carotid artery (ICA) and middle cerebral artery (MCA) were measured. Subjective image quality was evaluated. Effective dose (ED) was estimated.

RESULTS

CT attenuation and noise of the ICA and MCA in Group A were higher than those of Group B (all P < 0.001) while the SNRICA, SNRMCA, CNRICA, and CNRMCA of Group A at S4-5 were comparable to (P > 0.05) or higher than in Group B (P < 0.05). There was no difference in overall image quality between Group A S3-5 and Group B (P > 0.05). ED was 0.2 ± 0.0 mSv for Group A with 85 % ED reduction in comparison to Group B (1.3 ± 0.2 mSv).

CONCLUSION

Cerebral CTA at 70 kVp is feasible, allowing for substantial radiation dose reduction. SAFIRE S4 level is recommended for obtaining optimal image quality.

KEY POINTS

• 70 kVp cerebral CTA is feasible and provides diagnostic image quality. • 70 kVp cerebral CTA resulted in 85% effective dose reduction. • S4 level of SAFIRE is recommended for 70 kVp cerebral CTA.

Beyond stenosis detection: computed tomography approaches for determining the functional relevance of coronary artery disease

Coronary computed tomography angiography (CCTA) is an established imaging technique for the noninvasive assessment of coronary arteries. However, CCTA remains a morphologic technique with the same limitations as invasive coronary angiography in evaluating the hemodynamic significance of coronary stenosis. Different computed tomography (CT) techniques for the functional analysis of coronary lesions have recently emerged, including static and dynamic CT myocardial perfusion imaging and CT-based fractional flow reserve and transluminal attenuation gradient methods. These techniques hold promise for achieving a comprehensive appraisal of anatomic and functional aspects of coronary heart disease with a single modality.

High-pitch coronary CT angiography at 70 kVp with low contrast medium volume: comparison of 80 and 100 kVp high-pitch protocols

The purpose of this article is to evaluate image quality and radiation dose of prospectively electrocardiogram (ECG)-triggered high-pitch coronary computed tomography angiography (CCTA) at 70 kVp and 30 mL contrast medium.One hundred fifty patients with a heart rate ≤70 beats per minute (bpm) underwent CCTA using a second-generation dual-source computed tomography (CT) scanner and were randomized into 3 groups according to tube voltage and contrast medium volume (370 mg/mL iodine concentration) (100 kVp group, 100 kVp/60 mL, n = 55; 80 kVp group, 80 kVp/60 mL, n = 44; 70 kVp group, 70 kVp/30 mL, n = 51). Objective and subjective image quality along with the effect of heart rate (HR) and body mass index (BMI) was evaluated and compared between the groups. Radiation dose was estimated for each patient.CT attenuation and image noise were higher in the 80 and 70 kVp groups than in the 100 kVp group (all P < 0.001). Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were lower in the 70 kVp group than in the 80 and 100 kVp groups (all P < 0.05). There was no difference for subjective image quality between the groups (P > 0.05). HR did not affect subjective image quality (all P > 0.05), while patients with BMI <23 kg/m had higher image quality than patients with BMI ≥23 kg/m (P < 0.05). Compared with the 100 kVp group, the radiation dose of the 70 kVp group was reduced by 75%.In conclusion, prospectively ECG-triggered high-pitch 70 kVp/30 mL CCTA can obtain diagnostic image quality with lower radiation dose in selected patients with BMI <23 kg/m compared with 80/100 kVp/60 mL CCTA.