Low-kV ECG-Gated Dual-Phase CT Angiography in Aortic Dissection: Dose Reduction with Improved Aortic Root Image Quality

Q: What are the key findings of this study?

Dual-phase 100 kV prospective ECG-gated CTA reduced effective radiation dose by 48% (10.59 vs. 20.25 mSv, p<0.05) and improved Stanford Type A diagnostic accuracy to 100% vs. 80%.

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Suspected aortic dissection (n=80). Intervention: Dual-phase 100 kV CT angiography with prospective ECG-gating vs. Conventional single-phase 120 kV non-ECG-gated CT angiography. Primary outcome: Effective radiation dose (mSv) (p=<0.05).

Q: What does this research mean for the field?

Dual-phase 100 kV prospective ECG-gated CTA reduces radiation dose by 48% while improving image quality and diagnostic accuracy for Stanford Type A aortic dissection compared to conventional non-ECG-gated CTA. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To evaluate radiation dose reduction, image quality, and diagnostic accuracy of a dual-phase 100 kV prospective ECG-gated CT angiography protocol compared to conventional 120 kV non-ECG-gated CT angiography in patients with suspected aortic dissection.

Yanhong Chen; Jiwei Sun; Minghui Hua; Bo Li; Hong Zhang

doi:10.21203/rs.3.rs-10857243/v1

October 18, 2026Open Access

Low-kV ECG-Gated Dual-Phase CT Angiography in Aortic Dissection: Dose Reduction with Improved Aortic Root Image Quality

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Key result

Dual-phase 100 kV prospective ECG-gated CTA is linked to ~48% lower radiation dose.

P<0.05
n=80

Why the study?

Conventional non-ECG-gated CTA for acute aortic dissection generates cardiac motion artefacts at the aortic root that compromise diagnostic accuracy while exposing patients to substantial radiation.

Does a dual-phase 100 kV aortic CTA protocol with prospective ECG-gating reduce radiation dose and improve aortic root image quality and diagnostic accuracy compared to conventional 120 kV non-ECG-gated CTA in patients with suspected aortic dissection?

Key Points

To evaluate radiation dose reduction, image quality, and diagnostic accuracy of a dual-phase 100 kV prospective ECG-gated CT angiography protocol compared to conventional 120 kV non-ECG-gated CT angiography in patients with suspected aortic dissection.
Retrospective historical control study of 80 consecutive patients undergoing CT angiography for suspected aortic dissection.
Patients were grouped into conventional 120 kV non-ECG-gated CTA (n = 40) or dual-phase 100 kV CTA with prospective ECG-gating of the aortic root (n = 40), with propensity score matching applied.
Image quality was evaluated using subjective scoring, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR), along with effective dose and scan time.
The 100 kV protocol reduced effective dose by 48% (10.59 +/- 3.89 versus 20.25 +/- 3.28 mSv, p < 0.05) and scan time by 55% (11.36 +/- 1.41 versus 25.23 +/- 2.36 s, p < 0.05).
Aortic root motion artefact rate dropped from 90.0% to 7.5% (p < 0.05), alongside significantly superior SNR (24.35 +/- 2.25 versus 20.25 +/- 3.28, p < 0.05) and CNR (44.10 +/- 2.47 versus 34.20 +/- 3.25, p < 0.05).
Diagnostic accuracy for Stanford Type A dissection was 100% versus 80% (p < 0.05), with entry tear visualisation improving from 60.0% to 95.83%.

Study Design

Type

Observational (n=80)

Blinding

Single-blind

Multicenter

No

Structured PICO

Does a dual-phase 100 kV aortic CTA protocol with prospective ECG-gating reduce radiation dose and improve aortic root image quality and diagnostic accuracy compared to conventional 120 kV non-ECG-gated CTA in patients with suspected aortic dissection?

P

Population

80 consecutive patients (mean age 61 years, 36.25% female) with suspected or known aortic dissection undergoing whole-aorta CT angiography, excluding those with severe renal insufficiency or iodinated contrast allergy.

E

Exposure

Dual-phase 100 kV aortic CTA protocol on a 256-slice scanner with iDose4 iterative reconstruction (level 4): Phase 1 non-ECG-gated whole-aorta scan (pitch 1.007) followed immediately by Phase 2 prospective ECG-gated scan focused on the aortic root (reconstructed at 45% R-R interval), using intravenous iodixanol (320 mg/mL, 70-85 mL based on BMI at 3.5 mL/s).

C

Comparator

Conventional single-phase 120 kV non-ECG-gated spiral CTA of the entire aorta (pitch 0.14) on the same 256-slice scanner with iDose4 iterative reconstruction (level 4) and identical intravenous iodixanol contrast injection protocol (historical control group from January to June 2024).

O

Outcome

Objective image quality (CT attenuation, image noise, signal-to-noise ratio [SNR], and contrast-to-noise ratio [CNR]) and radiation dose reduction (effective dose in mSv).surrogate

Main Result

Absolute Event Rate: 10.59% vs 20.25%

p-value: p=<0.05

A dual-phase 100 kV prospective ECG-gated CTA protocol cuts radiation exposure nearly in half and reduces scan time by 55% while virtually eliminating aortic root motion artefacts and achieving 100% diagnostic accuracy for Stanford Type A aortic dissection.

Limitations

Single-centre retrospective design
Historical control design subject to potential selection bias and unmeasured confounding
Small sample size of 40 patients per group
Historical control design subject to potential selection bias and confounding
Small sample size of 40 patients per group based on availability of consecutive cases

Ask about this paper

Answers are grounded in this paper and cite their sources.

Implication

May reduce radiation and improve Type A dissection diagnosis; hypothesis-generating and requires prospective validation before practice change.

Abstract

Background and Objectives: Acute aortic dissection is a life-threatening condition. Computed tomography angiography (CTA) is the first-line modality; however, conventional non-ECG-gated protocols generate cardiac motion artefacts at the aortic root that compromise accuracy while exposing patients to substantial radiation. This retrospective study evaluated a dual-phase 100 kV aortic CTA protocol with prospective ECG-gating for dose reduction and improved image quality versus conventional 120 kV non-ECG-gated CTA. Materials and Methods: We retrospectively screened 80 consecutive patients with suspected aortic dissection undergoing CTA at Tianjin Chest Hospital (January 2024–December 2025) via the institutional Picture Archiving and Communication System (PACS) and electronic medical records. Patients were grouped by scanning protocol according to a historical control design: conventional 120 kV non-ECG-gated CTA (n = 40, January–June 2024) and dual-phase 100 kV CTA with prospective ECG-gating of the aortic root (n = 40, July 2024–December 2025). Image quality was assessed by subjective scoring and objective signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Effective dose, scan time, and diagnostic accuracy were compared between groups. Propensity score matching was applied to balance baseline characteristics. The ethics committee approved this study (no. 2024-LW-036; 15 December 2024) and waived informed consent. Results: The 100 kV protocol reduced effective dose by 48% (10.59 +/- 3.89 versus 20.25 +/- 3.28 mSv, p < 0.05) and scan time by 55% (11.36 +/- 1.41 versus 25.23 +/- 2.36 s, p < 0.05). The aortic root motion artefact rate fell from 90.0% to 7.5% (p < 0.05). SNR (24.35 +/- 2.25 versus 20.25 +/- 3.28) and CNR (44.10 +/- 2.47 versus 34.20 +/- 3.25) were significantly superior (both p < 0.05). Diagnostic accuracy for Stanford Type A dissection was 100% versus 80% (p < 0.05), with entry tear visualisation improving from 60.0% to 95.83%. Conclusions: The dual-phase 100 kV prospective ECG-gated protocol significantly reduces radiation exposure and scan duration whilst virtually eliminating aortic root motion artefacts and improving diagnostic accuracy for Stanford Type A dissection. These findings support adoption of this protocol as the preferred CTA technique for aortic dissection on 256-slice CT platforms.

Discussion

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Cite This Study

Chen et al. (2026) conducted an observational in Suspected aortic dissection (n=80). Dual-phase 100 kV CT angiography with prospective ECG-gating vs. Conventional single-phase 120 kV non-ECG-gated CT angiography was evaluated on Effective radiation dose (mSv) (p=<0.05). Dual-phase 100 kV prospective ECG-gated CTA reduced effective radiation dose by 48% (10.59 vs. 20.25 mSv, p<0.05) and improved Stanford Type A diagnostic accuracy to 100% vs. 80%.

synapsesocial.com/papers/6aee6b8671a75948062209ae https://doi.org/10.21203/rs.3.rs-10857243/v1

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Low-kV ECG-Gated Dual-Phase CT Angiography in Aortic Dissection: Dose Reduction with Improved Aortic Root Image Quality

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Low-kV ECG-Gated Dual-Phase CT Angiography in Aortic Dissection: Dose Reduction with Improved Aortic Root Image Quality

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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