[Preliminary study of individualized contrast injection protocols in triple-rule-out computed tomography angiography
Jinyan Li1, Guowei Zhang, Ximing Wang2
1Department of Radiology, Shandong Provincial Hospital, Jinan 250000, China.
Insights
Individualized contrast protocols in dual-source CT angiography for chest pain can achieve diagnostic image quality while reducing contrast agent volume and effective radiation dose in patients with stable heart rates.
Area of Science:
- Radiology
- Medical Imaging
- Cardiovascular Imaging
Background:
- Triple-rule-out computed tomography (CT) angiography is used for acute chest pain evaluation.
- Optimizing contrast injection protocols is crucial for image quality and patient safety.
Purpose of the Study:
- To evaluate the feasibility of individualized contrast injection protocols in dual-source CT angiography for triple-rule-out examinations.
- To compare image quality, contrast agent volume, and radiation dose between individualized and standard protocols.
Main Methods:
- Sixty-three patients with acute chest pain underwent ECG-synchronized dual-spiral CT angiography.
- Thirty-one patients with stable heart rates received an individualized triphasic contrast protocol in Flash mode.
- The remaining patients received a standard biphasic contrast protocol in retrospective mode.
Main Results:
- No significant differences in image quality (aorta, coronary arteries, SNR, CNR) were observed between groups.
- Pulmonary artery attenuation was lower but diagnostic in the individualized protocol group.
- The individualized protocol group used significantly less contrast agent and had a lower effective radiation dose.
Conclusions:
- Individualized contrast protocols are feasible and effective for triple-rule-out CT in patients with stable heart rates.
- This approach achieves diagnostic image quality with reduced contrast agent and radiation exposure.
- Dual-source CT with individualized protocols offers an optimized imaging strategy for acute chest pain.
Objective:
To assess the feasibility of individual contrast injection protocols in triple-rule-out computed tomography examination using a dual-source Flash-chest-pain technique.
Methods:
From April to August 2014, 63 patients with undifferentiated acute chest pain underwent ECG-synchronized dual-spiral chest CT angiography. 31 Patients, who all had low (<65 bpm) and stable heart rate underwent TRO CT angiography in a Flash mode, with an individual triphasic contrast protocol based on weight (350 mgI/ml, A: 0.7 ml/kg, setting 10 s duration time; B: 8 s mixture of the contrast agent and saline at the same rate; C: 6-7 s saline at the same rate). In contrast, the other patients, who had random heart rate, underwent TRO CT angiography in a traditional retrospectively mode with an identical biphasic contrast protocol (350 mgI/ml, A: contrast agent 90 ml, B: saline 40 ml, injection rate 5 ml/s). Quantitative image analysis assessed vessel attenuation of aorta, coronary and pulmonary artery, signal-to-noise ratio (SNR) and contrast-to noise ratio (CNR). Subjective image was assessed on a 5 point scale (1: excellent, 5:non-diagnosis) by two blind observers. The effective dose was calculated from the dose length product (DLP) using a conversion coefficient of 0.017 mSv·mGy(-1)·cm(-1).
Results:
There was no significant difference of aorta and coronary artery attenuation, noise, SNR, CNR or subjective image quality between both patient groups. Pulmonary artery attenuation was lower in test group than in control group, but it also can meet the diagnostic criteria. Moreover, the mean contrast agent and the effective dose were lower in test group than in control group (72±10) vs (90±0) ml, P<0.01 and (3.0±0.3) vs (18.8±2.7) mSv, P<0.01.
Conclusion:
As to patients with low and stable heart rate, this individual contrast protocol along with dual-source high-pith technique, is capable of achieving satisfactory image which could meet the diagnostic requirements with lower contrast agent and lower effective dose.
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