Keywords:
Cardiac, Radioprotection / Radiation dose, CT-Angiography, Technical aspects, Dosimetric comparison
Authors:
K. Van Looveren, R. Salgado, P. Van Herck, B. Shivalkar, T. De Bondt, P. M. Parizel; Antwerp (Edegem)/BE
Results
The statistical analysis of the study population showes a uniform distribution of patients in the different weight classes (Fig. 4).The coronary arteries are subdivided in 17 segments according to the AHA. There is a good overall interpretability of the coronary segments (Fig. 5) in all weight classes (class 0: 92%,
class 1: 96%,
class 2: 96%,
class 3: 92% and class 4: 94.8%).
The results show no decrease in image quality of the coronary arteries with increasing weight.
However,
this is at the expense of higher radiation dose.
In obesity class 4 the mean radiation dose (20.7 mSv) is almost twice as high as in class 0 (11.6 mSv) (Fig. 6). The mid RCA is the segment which was most often assessed as not interpretable: class 0: 4.1%,
class 1: 3.3%,
class 2: 2.7%,
class 3: 7.5% and class 4: 4.4% (Fig. 7).
This could be due to the vertical position of this segment which is more subject to moving artefacts.
There are 2919 patients scanned with the retrospective scanprotocol and 1156 patients with the prospective scanprotocol. Comparison of the mean radiation dose in these two groups (Fig. 8) shows a significant increase of radiation dose with the retrospective scanprotocol.
In class 0 the mean radiation dose is twice as high in retrospective CCTA compared to prospective CCTA (11.6 mSv versus 5.3 mSv) and this difference even increases in obesity class 3 (retrospectively 19.35 mSv versus 6.73 mSv) and obesity class 4 (retrospectively 20.72 mSv versus 7.34 mSv).