Subjects
- The difference of the demographic data including mean age,
gender ratio,
and BMI,
was not significant between the two subject groups.
- The average heart rate during CCTA showed insignificant difference between two groups (mean heart rate: 59 ± 6.7,
P = 0.85).
- A total of 58 patients (29/29,
free breathing group/breath holding group) were performed unenhanced CT for calcium score.
; The average Agatston score was 153 ± 316.5 and no significant different between the two groups (P = 0.40).
- 15 patients showed previous inserted coronary stent,
26 patients had significant stenosis (>50% luminal stenosis) of the coronary artery and no significant different between the two groups.
The general characteristics and CCTA findings of each patient group are summarized in Table 1.
![](https://epos.myesr.org/posterimage/escr/escr2012/114382/media/466415?maxheight=300&maxwidth=300)
Table 1: General characteristics and CCTA findings of each patient groups.
Image quality
- A total of 963 coronary artery segments with a diameter ≥1.5 mm were available for evaluation of image quality
- The overall mean image quality score was 1.11 ± 0.32.
- The image quality was excellent (score 1) in 89.3% (860/963),
good (score 2) in 10.5% (101/963) and poor (score 3) in 1.4%
(2/963) (Table 2 ).
- No significant difference was noted between image quality
scores of the conservative method and free-breathing groups
(1.10 ± 0.31 vs.
1.12 ± 0.33,
respectively; P = 0.44).
- The mean background image noise (i.e.,
the SD of HU on ascending aorta) was 34.3 ± 6.7 HU,
and no significant differences were found between the two groups.
- The SNR and CNR on LM and proximal RCA revealed no significantly differences between the two groups (Table 2 ).
![](https://epos.myesr.org/posterimage/escr/escr2012/114382/media/466416?maxheight=300&maxwidth=300)
Table 2: Comparison between the two acquisition methods for image noise, signal to noise ratio (SNR), contrast to noise ratio (CNR), and image quality score
Radiation dose
- During CCTA scanning,
the average mAs was 370 ± 84.8 mAs (range,
160–540 mAs).
In 73% of the cases (54/74),
tube voltage was set to 120 kVp,
the other 27% (20/74) was scanned with 100 kVp.
- The overall mean effective dose; 6.0 ± 1.9 mSv
- Mean CTDIvol,
scan length,
DLP,
and effective dose were not significantly different between the two groups (Table 3).
![](https://epos.myesr.org/posterimage/escr/escr2012/114382/media/466417?maxheight=300&maxwidth=300)
Table 3: Image scanning parameters, radiation dose estimates in the two groups of patients with different coronary computed tomography angiography (CCTA) protocols.
Cases
![](https://epos.myesr.org/posterimage/escr/escr2012/114382/media/466418?maxheight=300&maxwidth=300)
Fig. 2: Fig. 1. A 49-year-old woman who presented for coronary computed tomography angiography (CCTA) because of syncope. a–f, Free-breathing prospective CCTA images; short axis multiplanar reconstruction (a), Four-chamber multiplanar reconstructed (b), volume rendered (c), and curved reformatted images (d–f) show the clearly defined coronary arteries (arrows) without a motion artifact.
![](https://epos.myesr.org/posterimage/escr/escr2012/114382/media/466419?maxheight=300&maxwidth=300)
Fig. 3: A 49-year-old woman had a pacemaker inserted due to a complete atrioventricular block about 2 years ago. She underwent coronary computed tomography angiography (CCTA) twice, before (a–c) and after (d–f) repositioning of a pacemaker. a–c, Breath-holding prospective CCTA images. Short-axis multiplanar reconstructed (a) and curved reformatted images (b, c) show relatively well-defined coronary arteries except the beam hardening artifact at the proximal right coronary artery due to the pacemaker electrode (arrows). d–f, Free-breathing retrospective CCTA performed after 2 months. Short-axis multiplanar reconstructed (d) and curved reformatted images (e, f) clearly show defined coronary arteries. Similar image quality was achieved as with the previous examination except for a wider field of view.
![](https://epos.myesr.org/posterimage/escr/escr2012/114382/media/466420?maxheight=300&maxwidth=300)
Fig. 4: A 69-year-old man with chest pain who underwent a stent insertion procedure in the left anterior descending coronary artery about 10 years ago. a–f, Free-breathing retrospective coronary computed tomography angiography (CCTA) images. a, b, Short-axis multiplanar reconstructed (a) and four-chamber multiplanar reconstructed (b) images show relatively well defined coronary arteries (arrows in b) and previously inserted stent (arrow in a). c, Volume rendering images reveal severe luminal narrowing of the just proximal segment of the coronary stent in the left anterior descending artery. Also noted was an irregular lumen in the left circumflex coronary artery. d–f, Curved reformatted images for the left anterior descending artery show narrowing with mixed plaques (arrowheads in e) in the proximal segment and the in-stent partial restenosis (f).