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Updated: Jul 15, 2026
Retrospective Cardiac Gating with A Prototype Small-Animal X-ray Computed Tomograph
Published on: February 21, 2025
Optimization of contrast material administration for electrocardiogram-gated computed tomographic angiography of the
Thorsten R C Johnson1, Konstantin Nikolaou, Bernd J Wintersperger
1Department of Clinical Radiology, Medical Clinic I, University of Munich-Grosshadern Campus, Marchioninistrasse, Munich, Germany. thorsten.johnson@med.uni-muenchen.de
Insights
Optimizing contrast timing in electrocardiogram-gated computed tomographic angiography (ECTA) using bolus-tracking enhances diagnostic accuracy for acute chest pain. This method ensures reliable opacification of pulmonary and systemic vasculature.
Area of Science:
- Radiology
- Medical Imaging
- Cardiovascular Imaging
Background:
- Electrocardiogram-gated computed tomographic angiography (ECTA) is vital for diagnosing acute chest pain.
- Optimal contrast material injection timing is crucial for effective ECTA.
Purpose of the Study:
- To evaluate optimal contrast material injection timing for ECTA.
- To compare test bolus and bolus-tracking techniques for scan delay determination.
Main Methods:
- Thirty patients underwent ECTA with contrast timing determined by test bolus or bolus-tracking.
- Contrast volume and flow were adjusted based on body weight.
- Attenuation profiles of vascular districts were analyzed.
Main Results:
- Excellent and homogeneous contrast enhancement (>200 HU) was achieved in most patients.
- Both techniques showed minimal variability in pulmonary and aortic enhancement.
- Simultaneous opacification of pulmonary and systemic vasculature was reliable.
Conclusions:
- Bolus-tracking in the ascending aorta optimizes contrast administration for ECTA.
- Body weight-adapted contrast protocols ensure consistent opacification.
- This approach improves diagnostic reliability in acute chest pain evaluation.
Objective:
Electrocardiogram-gated computed tomographic angiography is increasingly used in the differential diagnosis of acute chest pain. We studied the optimal timing of contrast material injection using a test bolus and a bolus-tracking technique.
Materials And Methods:
Thirty patients were prospectively included in the study. Volume and flow of high concentration contrast material were adapted to body weight. The scan delay was determined using either a test bolus or a bolus-tracking technique. Attenuation profiles of the different vascular districts were measured to evaluate the timing techniques.
Results:
In all the patients except for one, an adequate and homogeneous contrast enhancement of more than 200 Hounsfield units (HU) was achieved (285 +/- 45 HU) in the different vascular districts. The pulmonary transit time in the test bolus group was 7 seconds (range, 4-11 seconds). Differences and variability of pulmonary and aortic enhancement were small in both groups (13 +/- 48 HU vs -9 +/- 21 HU), with differences of less than 70 HU over the craniocaudal range and very small intraindividual differences between pulmonary attenuation and systemic attenuation.
Conclusions:
Contrast administration regimens for electrocardiogramgated computed tomographic angiography of the chest can be optimized using the bolus-tracking method in the ascending aorta, with a short delay after trigger. Body weight adaptation of volume and injection rate of the contrast material results in a reliable simultaneous opacification of the pulmonary and systemic vasculature.
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