Keywords:
Cardiovascular system, Cardiac, CT, Diagnostic procedure, Ischaemia / Infarction, Arteriosclerosis
Authors:
M. Williams1, S. Golay1, N. Weir1, S. Mirsadraee1, E. J. R. Van Beek1, J. Reid2, G. McKillop1, N. Uren1, D. E. Newby1; 1Edinburgh/UK, 2Melrose, Roxburghshire/UK
DOI:
10.1594/ecr2013/B-0373
Methods and Materials
Participants underwent rest computed tomography coronary angiography and adenosine stress computed tomography myocardial perfusion imaging using a 320-multidetector scanner (Aquilion ONE,
Medical Systems,
Japan).
Contrast volume was selected based on body mass index.
For Group 1 tube current was selected based on body mass index,
multi-segment acquisition was used,
120kV was used for all patients and images were reconstructed using a filtered back projection reconstruction algorithm (QDS+). For Group 2 tube current was automatically adjusted based on scout image attenuation (SureExposure,
Toshiba Medical systems),
tube voltage was selected based on body mass index (100kV for BMI <30 kg/m2,
120kV for BMI >30 kg/m2) and images were reconstructed using half-segment reconstruction and an iterative reconstruction algorithm (AIDR3D) with the standard level of blending.
(Table 1)
Dose length product (DLP) was recorded.
Image noise was assessed as the standard deviation of Hounsfield units within a region of interest in the ascending aorta in the midpoint of the volume.
Subjective image quality was assessed (1,
excellent; 4,
uninterpretable) for each of the 17 myocardial segments.
These were summed to give a total image quality score.
|
Group 1 |
Group 2 |
Reconstruction algorithm |
Filtered back projection (QDS+) |
Iterative reconstruction (AIDR3D) |
Tube voltage |
120kV for all |
Tailored to BMI |
Segments for reconstruction |
Multisegment if >65 beats per minute |
Half segment reconstruction for all |
Dose modulation |
None |
For stress imaging with 70-80% of the RR interval at full dose |
Sublingual glyceryl trinitrate |
None |
For rest scan |
Protocol details for Groups 1 and 2