30 studies (61.2%) were performed with cardiac-gating and 19 (38.8%) without it.
Of the 49 studies,
16 (32.7%) were performed with a tube voltage of 80 kV,
24 (49%) with 100 kV,
and 9 (18.4%) with 120 kV.
1.
Demographics Parameters.
Table 1.
2.
Image quality
- Aorta - Table 2.
- Coronary Arteries:
A total of 440 coronary artery segments were evaluated by both observers in the 30 studies performed with cardiac synchronization.
67.73% (298/440) of these segments were diagnostic with an image quality good (87.3%) or acceptable (12.7%).
32.27% (142/440) were nondiagnostic secondary to inadequate quality image (34.5%),
severe wall calcifications (16.9%) or reduced vessel diameter (48.6%).
The interobserver agreement for image quality grading was good (ҡ = 0.69).
A total of 180 proximal segments (proximal and mid RCA,
LM,
proximal and mid LAD and proximal LCx) were evaluated.
82.22% (148/180) of these segments were diagnostic.
17.78% (32/180) were nondiagnostic secondary to inadequate quality image (56.3%),
severe wall calcifications (40.6%) or reduced vessel diameter (3.1%).
The interobserver agreement for image quality grading of proximal coronary artery segments was good (ҡ = 0.68).
The percentage of nondiagnostic segments secondary to motion artifacts for a heart rate ≥ 63 bpm was 20.66%,
while the percentage of nondiagnostic segments for a heart rate < 62 bpm was 12.16%.
This difference was not statistically significant (p=0.06).
The percentage of nondiagnostic segments secondary to motion artifacts for an arrhythmic heart rate was 32.05%,
while the percentage of nondiagnostic segments for a rhythmic heart rate was 10.91%.
This difference was statistically significant (p=0.0001).
If patients with an arrhythmic heart rate are excluded,
the percentage of nondiagnostic segments secondary to motion artifacts for a heart rate ≥ 63 bpm was 16.19%,
while the percentage of nondiagnostic segments for a heart rate < 62 bpm was 6.09%.
This difference was statistically significant (p=0.01).
3.
Employed time to evaluation of coronary arteries
The mean time used for the assessment of the coronary arteries (not only image quality but also analysis of coronary artery anatomy and pathology) was of 8’6’’ ± 3’28’’ (range,
5-17‘).
4.
Radiation dose
The mean effective radiation dose for all patients was 4.64 ± 2.03 mSv (range,
2.02 – 9.99 mSv); 4.91 ± 2.12 mSv (range,
2.02 - 9.99 mSv) in synchronized studies and 4.22 ± 1.85 mSv (range,
2.32 – 8.53 mSv) in studies without cardiac synchronization (p=0.25).
