Keywords:
Artifacts, Technical aspects, CT, Cardiac
Authors:
E.-J. Kang1, K.-N. Lee1, J.-M. Lee2, J. Y. Oh1, B.-H. Park1, H. J. Kwon1, D. H. Ha1, D. W. Kim1; 1Busan/KR, 2Daegu/KR
Purpose
-Coronary CT angiography (CCTA) examinations have been traditionally performed in a breath-holding state to reduce the artifacts caused by respiration.However,
some patients cannot hold their breath,
or their heart rate increases during breath holding.
![](https://epos.myesr.org/posterimage/escr/escr2012/114382/media/466411?maxheight=300&maxwidth=300)
Fig. 1:
Hear is one of the example of the patient increased heart rate during the breath holding exercise before start CT scan.
-To date,
320-detector row CT scanner allows for 16 cm z-axis coverage; These CT machines are able to perform a nonspiral ECG gated examination of the heart during one R-R interval without movement of the table.
- Diaphragm velocity by respiration: 6.4~29.3mm/sec
[Normal respiratory rate for adults (at rest); 12~20 breaths/min,
Excursion range of diaphragm during voluntary sniffing; 1.6~4.4 cm (4)]
- Coronary artery shifting velocity by cardiac pulsation: 22.4~108.6 mm/sec [Mao et al.
(5)]
-During CCTA acquisition using a 320-detector CT (0.175 second temporal resolution),the maximal traveling range provoked by respiration and cardiac pulsation can be calculated as 5.1 mm and 19.0 mm,
respectively.
=> We can imagine the shifting of coronary artery by respiration is much less than that by cardiac pulsation!
-Our hypothesis is that,
in the case of CCTA with a 320-detector CT scanner during one cardiac cycle,
gentle steady breathing may not produce an additional significant motion artifact.
-In this study,
we investigated the feasibility of 320-detector free-breathing CCTA in terms of image quality and radiation dosage.