Siemens SOMATOM SENSATION CARDIAC A60 - Manual (Page 26)

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HeartView CT
Technical Principles
Basically, there are two different technical approaches
for cardiac CT acquisition:
• Prospectively ECG triggered sequential scanning.
• Retrospectively ECG gated spiral scanning.
In both cases, an ECG is recorded and used to either
initiate prospective image acquisition (ECG triggering),
or to perform retrospective image reconstruction
(ECG gating). A given temporal relation relative to the
R-waves is predefined and can be applied with the
following possibilities:
Relative – delay: a given percentage of R-R interval (_RR)
relative to the onset of the previous or the next R-wave
(Fig. 9, 10).
Time
Time
ECG
(t)
ECG
(t)
50 % of R-R
-50 % R-R
Scan/
Recon
Scan/
Recon
Fig. 9
Fig. 10