Purpose: ECG-gated CTA allows visualization of the aneurysm and stentgraft during the different phases of the cardiac
cycle, although with a lower SNR per cardiac phase than without ECG gating using the same dose. In our institution,
abdominal aortic aneurysm (AAA) is evaluated using non-ECG-gated CTA. Some common CT scanners cannot reconstruct a non-gated volume from ECG-gated acquired data. In order to obtain the same diagnostic image quality, we propose off-line temporal averaging of the ECG-gated data. This process, though straightforward, is fundamentally different from taking a non-gated scan, and its result will certainly differ as well. The purpose of this study is to quantitatively investigate how good off-line averaging approximates a non-gated scan.
Method: Non-gated and ECG-gated CT scans have been performed on a phantom (Catphan 500). Afterwards the phases
of the ECG-gated CTA data were averaged to create a third dataset. The three sets are compared with respect to noise prop-erties (NPS) and frequency response (MTF). To study motion artifacts identical scans were acquired on a programmable dynamic phantom.
Results and Conclusions: The experiments show that the spatial frequency content is not affected by the averaging
process. The minor differences observed for the noise properties and motion artifacts are in favor of the averaged data. Therefore the averaged ECG-gated phases can be used for diagnosis. This enables the use of ECG-gating for research on stentgrafts in AAA, without impairing clinical patient care.
|Title of host publication||Proceedings of SPIE Medical Imaging 2008|
|Editors||Ehsan Samei, Jiang Hsieh|
|Number of pages||6|
|Publication status||Published - Feb 2009|
|Event||SPIE Medical Imaging 2008 - Town & Country Resort and Convention Center, San Diego, United States|
Duration: 16 Feb 2008 → 21 Feb 2008
|Conference||SPIE Medical Imaging 2008|
|Period||16/02/08 → 21/02/08|
- ECG gating