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DOI: 10.1055/s-0032-1311336
Estimated Radiation Dose Reduction for Prospective Electrocardiography-Triggered Dual Source CT Angiography of the Thoracic Aorta using Iterative Reconstruction: A Prospective Study
Ziele: To prospectively investigate image quality and radiation dose reduction for prospective ECG-triggered sequential dual-source (DS) CTA using iterative reconstruction of the thoracic aorta in comparison to prospective ECG-triggered sequential dual-source (DS) CTA with standard filtered back-projection (FBP). Methode: This study was institutional review board-approved; informed consent was obtained. 260 consecutive patients referred for ECG-assisted DS CTA of the thoracic aorta were prospectively enrolled. Tube voltage was adjusted to body mass index (<25.0kg/m2, 100kV, n=95; ≥25.0kg/m2, 120kV, n=165), tube current was centered at 250ms past the R-peak. Patients were randomly assigned to a CT-protocol with reduced reference tube current of either 100, 150 or 200mAs/rot employing iterative reconstruction and were compared to a reference cohort previously examined with our institutional standard protocol (250mAs/rot, FBP). Image noise and subjective image quality were assessed. Effective radiation dose was calculated from the dose-length product. Ergebnis: Mean estimated effective dose was significantly lower for protocols with reduced tube current (200, 150, 100mAs/rot) compared to the standard protocol with 250mAs/rot (100kV, 1.6±0.4mSv, 1.2±0.3mSv, 0.8±0.3mSv vs. 1.9±0.6mSv, p<0.001; 120kV, 3.9±1.1mSv, 2.9±0.9mSv, 1.8±0.4mSv vs. 4.7 ±1.1mSv, p<0.001). With decreasing tube current, image noise increased but did not reach level of the standard protocol. Subjective image quality decreased with decreasing tube current, but image quality of the 100mAs/rot subgroups was equivalent to the standard protocol (100kV, 1.9 vs. 2.0; 120kV, 2.0 vs. 2.0, p=n.s.). Schlussfolgerung: Iterative reconstruction allows for reduction of applied tube current and therby for dose reduction of approximately 60% in CTA of the thoracic aorta while maintaining objective and subjective image quality when compared to a standard protocol with filtered back-projection.
Keywords: Iterative Reconstruction, Dose Reduction, Computed Tomography, CTA
Korrespondierender Autor: Blanke P
Universitätsklinikum Freiburg, Röntgendiagnostik, Hugstetter Strasse 55, 79106 Freiburg
E-Mail: philipp.blanke@uniklinik-freiburg.de