Abstract
To evaluate the effect of radiation dose reduction on image quality and diagnostic confidence in contrast-enhanced whole-body computed tomography (WBCT) staging. We randomly selected March 2016 for retrospective inclusion of 18 consecutive patients (14 female, 60 ± 15 years) with clinically indicated WBCT staging on the same 3rd generation dual-source CT. Using low-dose simulations, we created data sets with 100, 80, 60, 40, and 20% of the original radiation dose. Each set was reconstructed using filtered back projection (FBP) and Advanced Modeled Iterative Reconstruction (ADMIRE®, Siemens Healthineers, Forchheim, Germany) strength 1–5, resulting in 540 datasets total. ADMIRE 2 was the reference standard for intraindividual comparison. The effective radiation dose was calculated using commercially available software. For comparison of objective image quality, noise assessments of subcutaneous adipose tissue regions were performed automatically using the software. Three radiologists blinded to the study evaluated image quality and diagnostic confidence independently on an equidistant 5-point Likert scale (1 = poor to 5 = excellent). At 100%, the effective radiation dose in our population was 13.3 ± 9.1 mSv. At 20% radiation dose, it was possible to obtain comparably low noise levels when using ADMIRE 5 (p = 1.000, r = 0.29). We identified ADMIRE 3 at 40% radiation dose (5.3 ± 3.6 mSv) as the lowest achievable radiation dose with image quality and diagnostic confidence equal to our reference standard (p = 1.000, r > 0.4). The inter-rater agreement for this result was almost perfect (ICC ≥ 0.958, 95% CI 0.909–0.983). On a 3rd generation scanner, it is feasible to maintain good subjective image quality, diagnostic confidence, and image noise in single-energy WBCT staging at dose levels as low as 40% of the original dose (5.3 ± 3.6 mSv), when using ADMIRE 3.
Highlights
Malignant diseases are the most common indication for computed tomography (CT)imaging [1]
We calculated effective radiation dose (ED) values for 80% radiation dose to be at 10.7 ± 7.2 Mean Estimated Effective Radiation Dose (mSv), and for 60% radiation dose at 8.3 ± 5.7 mSv
At 40% radiation dose, ED was calculated to be at 5.3 ± 3.6 mSv, and 20%
Summary
Malignant diseases are the most common indication for computed tomography (CT)imaging [1]. There has been a growing concern regarded increased radiation exposure by radiological examinations and the contribution of CT scans especially [2]. Previous studies have shown a significant rise in lifetime mortality in oncological patients from radiation-induced secondary malignancies [6]. In contrast to filtered back projection (FBP), the widespread adoption of iterative reconstruction (IR) algorithms has opened up a multitude of approaches for low dose CT image acquisition due to their superior noise and artifact reduction [13]. Other studies with a similar methodological approach to our study in patients with suspected cervical abscesses, and pulmonary angiography for suspected pulmonary embolisms respectively, have shown a large potential for image quality improvements at low tube acquisition in combination with iterative reconstruction techniques on 3rd generation CT scanners [14,15]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have