Cardiac, Cardiovascular system, CT, CT-Angiography, Image manipulation / Reconstruction, Comparative studies, Technical aspects, Cardiac Assist Devices
F. Tatsugami, T. Higaki, M. Kiguchi, S. Date, K. Awai; Hiroshima/JP
In our study,
the noise reduction rate increased in proportionto the time for the R-R interval.
Because a redundant temporal window (padding) was acquired in a very short time-width (70-80% of the R-R interval),
there was substantial overlapping among the three data sets of 70-,
and 80% images.
We posit that the time width in the 70-80% of the R-R interval correlates with the extent of overlap among the three images.
When the time width in the padding was long,
the overlap was small.
The lower the degree of overlap,
the higher was the noise reduction rate, thus validating our results.
Our study was limited to patients with a heart rate lower than 63 bpm and in all studies we used prospective ECG-triggering.
Since the noise reduction rate increased in proportionto the time for the R-R interval,
we suggest that our method is applicable in patients with a lower heart rate. While it is feasible for patients whose heart rate is 64 bpm or higher,
the noise reduction rate would be lower.
As our method facilitated an image noise reduction of approximately 20% with improved image quality,
it may also allow for a radiation dose reduction at coronary CTA.
Because the image noise is inversely related to the square root of the tube current ,
it may be possible to reduce the radiation exposure by 36% at coronary CTA with prospective ECG-triggering.
We did not confirm the diagnostic accuracy of our coronary CTA images by comparing our findings with the reference standard,
invasive coronary angiography.