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Retrospective gating

Fig. 15.5. Retrospectively gated image acquisition by CT does not only contain information about the coronary arteries but also about the function of the myocardium. Newer postprocessing is under development, and tries to determine the axial CT slices reconstructed at different time points of the cardiac cycle. These workstations may provide data about the global functional parameter, as well as regional wall motion abnormalities... Fig. 15.5. Retrospectively gated image acquisition by CT does not only contain information about the coronary arteries but also about the function of the myocardium. Newer postprocessing is under development, and tries to determine the axial CT slices reconstructed at different time points of the cardiac cycle. These workstations may provide data about the global functional parameter, as well as regional wall motion abnormalities...
In summary, a prospectively acquired scan with a large detector versus a regular helical acquisition with retrospective gating reduces the dose exposure by a factor... [Pg.220]

Earls JP, Berman El, Urban BA, Curry CA, Lane JL, Jennings RS, McCulloch CC, Hsieh J, Londt JH (2008) Prospectively gated transverse coronary CT angiography versus retrospectively gated helical technique improved image quality and reduced radiation dose. Radiology. Radiology 246 742-753... [Pg.223]

Fig. 20.4a-c. Retrospective reconstruction of a multiphasic dataset scanned with a DSCT scanner. Without exposing the patient to additional radiation exposure or contrast material application, a number of datasets can retrospectively be reconstructed from any coronary CT angiographic scan if a retrospective gating technique is used. For example, images can be... [Pg.257]

To ensure accuracy, all samples and the reference material should be examined under identical conditions, preferably in the same analysis session by the same operator. Operator-specific variations arise from disparities in the perception of what constitutes a good data set, and where varions limits should be applied, i.e. the depth range, intensity range, retrospective gating applied, and so on. [Pg.262]

In addition, retrospective ECG gating allows for reconstruction of images at any time within the cardiac cycle. Setting the images together that are reconstructed every 50 ms after the R wave in the ECG allows visualization of the cardiac function in real time with a temporal resolution of 20 frames per second. The functional CT data can be evalu-... [Pg.215]

Ohnesorge B, Flohr T, Fischbach R et al (2002) Reproducibility of coronary calcium quantification in repeat examinations with retrospectively ECG-gated multisection spiral CT. Eur Radiol 12 1532-1540... [Pg.220]

With retrospective ECG gating, the heart volume is covered continuously by a spiral scan. The patients ECG signal is recorded simultaneously to data acqui-... [Pg.17]

Fig. 1.15. Principle of retrospectively ECG-gated spiral scanning with single-segment reconstruction. The patient s ECG signal is indicated as a function of time on the horizontal axis, and the position of the detector slices relative to the patient is shown on the vertical axis (in this example for a four-slice CT system). The table moves continuously, and continuous spiral scan data of the heart volrnne are acquired. Only scan data acquired in a pre-defined cardiac phase, usually the diastolic phase, are used for image reconstruction (indicated as red boxes). The spiral interpolation is illustrated for some representative projection angles... Fig. 1.15. Principle of retrospectively ECG-gated spiral scanning with single-segment reconstruction. The patient s ECG signal is indicated as a function of time on the horizontal axis, and the position of the detector slices relative to the patient is shown on the vertical axis (in this example for a four-slice CT system). The table moves continuously, and continuous spiral scan data of the heart volrnne are acquired. Only scan data acquired in a pre-defined cardiac phase, usually the diastolic phase, are used for image reconstruction (indicated as red boxes). The spiral interpolation is illustrated for some representative projection angles...
Jakobs TF, Becker CR, Ohnesorge B, Flohr T, Suess C, Schoepf UJ, Reiser MF (2002) Multislice helical CT of the heart with retrospective ECG gating reduction of radiation exposure by ECG-controlled tube current modulation. Eur Radiol 12 1081-1086... [Pg.23]

Electrocardiographic-TriggeringZ-Gating (Prospective, Retrospective) Scan Modes 28... [Pg.25]

Gated imaging without table movement requires a new way of thinking in terms of protocol selection. The smooth transition between prospective triggering and retrospective reconstruction offers the user complete freedom in tailoring the scan to the clinical question. For each patient, the protocol is optimized balancing the required cardiac phases, temporal resolution, and the radiation dose. Patient comfort is also increased due to the very short breath hold times and no distracting table movement. [Pg.30]

Retrospective ECG gating represents the most commonly used technique of data reconstruction in CT... [Pg.195]

Fig. 15.2a-e. (continued) Retrospectively ECG-gated dualsource CT coronary angiography in a 67-year-old woman with tachycardia and recurrent atypical chest pain. The mean heart... [Pg.199]

Fig. 15.3a-c. (continued) Retrospectively ECG-gated dualsource CT coronary angiography in a 56-year-old man with recurrent atypical chest pain and an inconclusive stress test. The mean heart rate during scanning was 68 bpm. The vol-miie-rendered image (b) similarly demonstrates the site of the stenosis (arrow). Invasive CCA (c) confirms the findings from CT (arrow)... [Pg.203]

Carbone I, Francone M, Algeri E etal. (2008) Noninvasive evaluation of coronary artery stent patency with retrospectively ECG-gated 64-slice CT angiography. Eur Radiol 18 234-243... [Pg.231]

Achenbach S, Ulzheimer S et al. (2000) Noninvasive coronary angiography by retrospectively ECG-gated multislice spiral CT. Circulation 102 2823 2828... [Pg.293]

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