- Meeting abstract
- Open Access
144 Prospective self-gating for simultaneous compensation of cardiac and respiratory motion
© Curcic et al; licensee BioMed Central Ltd. 2008
- Published: 22 October 2008
- Respiratory Motion
- Respiratory Signal
- Respiratory Gating
- Cardiac Trigger
- Gating Window
Data acquisition in cardiac imaging has to be synchronized with heart and respiratory motion. For this purpose an electrocardiogram (ECG) in combination with a breath-hold or a respiratory navigator is usually applied. However, these motion monitoring techniques, necessitate patient cooperation and increase the complexity of the examination. Furthermore, the ECG signal may be distorted by radio-frequency and gradient action and the navigator signal might not precisely represent the respiratory motion of the heart. In this work a prospective, self-gated approach for free breathing cardiac imaging is presented requiring neither of the monitoring techniques described above. The motion data used for cardiac triggering and respiratory gating are extracted and processed in real-time from repeatedly acquired data at the k-space center. Image quality with the proposed method was found to be comparable to ECG triggered breathheld acquisitions while the scan efficiency was significantly increased.
To test the feasibility of the approach a cardiac four-chamber view of a healthy volunteer was acquired (TR = 4.5 ms, TE = 2.6 ms, flip angle = 60°, scan matrix = 192 × 186, FOV = 320 × 320 mm2, slice thickness = 8 mm, 11 lines/segment, 30 cardiac phases) using a five channel cardiac coil array. To asses the quality of the extracted self-gating motion curves, signals from an ECG and a respiratory belt were simultaneously acquired and stored. As reference a retrospective self-gating acquisition described in  was performed. In the retrospective approach the data are evaluated after the acquisition, therefore requiring temporal oversampling of the data to ensure that every profile is acquired at least once in an acceptable motion state. Additionally, a standard ECG triggered breathheld acquisition was acquired as second reference.
It has been shown that cardiac and respiratory variations can be accurately detected prospectively using signals originating from the k-space center and thereby eliminating the need for external cardiac and respiratory signal detection. Compared to the retrospective self-gating approach total scan time could be reduced while image quality was well maintained.