Siemens SOMATOM SENSATION CARDIAC A60 - Manual (Page 25)

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HeartView CT
Cardiac Cycle and ECG
The heart contracts when pumping blood and rests
when receiving blood. This activity and lack of activity
form a cardiac cycle, which can be illustrated by an
Electrocardiograph (ECG) (Fig. 8).
To minimize motion artifacts in cardiac images, the
following two requirements are mandatory for a CT
system:
• Fast gantry rotation time in order to achieve fast
image acquisition time
• Prospective synchronization of image acquisition
or retrospective reconstruction based on the ECG
recording in order to produce the image during the
diastolic phase when the least motion happens.
Temporal Resolution
Temporal resolution, also called time resolution,
represents the time window of the data that is used for
image reconstruction. It is essential for cardiac CT
imaging – the higher the temporal resolution, the fewer
the motion artifacts. With the SOMATOM Sensation
Cardiac, temporal resolution for cardiac imaging can
be achieved at down to 105 ms.
Fig. 8
R
T
U
S Q
P
Ventricular contraction
Systolic phase
Atrial contraction
Diastolic phase
Relaxation
Diastolic
phase