The optimal dose reduction level using iterative reconstruction with prospective ECG-triggered coronary CTA using...

Area of Science:

• Radiology and Imaging
• Cardiovascular Imaging
• Medical Physics

Background:

• Coronary computed tomography angiography (coronary CTA) is crucial for diagnosing coronary artery disease.
• Radiation dose reduction is a key concern in CT imaging, especially for repeated procedures.
• Iterative reconstruction (IR) techniques offer potential for dose reduction compared to traditional filtered back projection (FBP).

Purpose of the Study:

• To evaluate the image quality (IQ) of i(Dose)4 IR on a 256-slice MDCT scanner for prospective ECG-triggered coronary CTA.
• To determine the optimal dose reduction using IR that maintains IQ comparable to FBP.
• To assess the effective dose (ED) reduction achievable with IR.

Main Methods:

• 110 patients underwent coronary CTA using a 256-slice MDCT scanner.
• Groups were scanned with varying tube outputs (mAs) and reconstructed with FBP (control) or IR (iDose(4) levels L3-L5).
• Image quality was assessed using subjective (radiologist grading) and objective (noise, SNR, CNR) metrics; ROC analysis identified optimal dose reduction.

Main Results:

• No significant differences in objective noise, SNR, or CNR were found between FBP and IR groups.
• Subjective image quality scores were comparable across groups, with no significant differences noted.
• A 60% tube output reduction (Group D) using IR (L5) achieved excellent IQ comparable to FBP, with a 63% lower effective dose (1.2 mSv vs. 3.2 mSv).

Conclusions:

• Iterative reconstruction (iDose(4)) enables significant radiation dose reduction in prospectively-triggered coronary CTA.
• A 63% reduction in effective dose is achievable with IR on a 256-slice MDCT scanner without compromising image quality.
• IR techniques provide a safe and effective method for dose reduction in cardiac CT imaging.