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Retrospective gating
Retrospective gating fundamentally differs from prospective
triggering. No actual triggering is taking place. The physiological
signal and data acquisition times are recorded simultaneously. The
measurement is performed completely independently of the patient’s
heartbeat or pulse. A temporal assignment of images to the
corresponding phase (e.g. heart stimulation) is performed after the
measurement (retrospectively).
In particular, retrospective gating is used to acquire images of the
beating heart. As compared to measurements using prospective
triggering, this technique is especially useful for displaying the late
diastole. Temporal resolution is freely selectable and may be higher
or lower than selected for the measurement.
Retrospective gating can be used for ECG, pulse, or external trigger
signal curves.
Physiological Measurement Unit (PMU)
Description
The Physiological Measurement Unit (PMU) lets you control MR
measurement sequences using a patient's physiological signals (ECG,
respiration and pulse).
The PMU consists of the following components:
◾
PERU (Physiologic ECG and Respiratory Unit): ECG and respiratory
sensor
◾
PPU (Peripheral Pulse Unit): Pulse sensor
◾
External trigger input
The physiological signals are acquired with receptors - ECG
electrodes, respiratory cushion and pulse sensor - directly at the
patient via the PERU (ECG, respiration) and PPU (pulse). The
measured data can be viewed at the Dot display in the examination
room and in the Physiological Display dialog window at the syngo
Acquisition Workplace.
4.1.2
4.2
4.2.1
4
Physiological imaging
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MR System | Operator Manual
Print No. M6-04401.621.02.02.02