Introduction: In coronary computed tomography angiography (CTA),
prospective ECG triggering scanning can be used in patients with a stable sinus rhythm and a low heart rate [1,
In this technique,
the CT scan is usually performed at the center of the mid-diastole phase at around 75% of the R-R interval .
As the best phase for diagnosis varies from patient to patient,
redundant scan data (padding) centered on mid-diastole are usually acquired [3,
A final image for evaluation of the...
Methods and Materials
Outline of the multi-phase data-averaging technique (Fig.
1): In general,
multiple data acquisitions of an object and their averaging at CT yields lower image noise than dose single data acquisition . Our new method uses three different cardiac phase images to reduce image noise. While coronary CTA with prospective ECG-triggering is usually performed in the center of the mid-diastole phase,
data can be acquired at the off-center of the temporal window if redundant scan time (padding) is...
The mean heart rate during the acquisition of CT scans was 51.9 ± 5.1 bpm (range 45 - 63 bpm); the mean effective radiation dose was 4.9 ± 1.1 mSv. Our quantitative image quality parameters are shown in Table 1.
The mean image noise on the de-noised images was significantly lower than on conventional 75% images ( P < 0.01).
The CNR in the proximal coronary arteries was significantly higher on de-noised- than conventional 75% images ( P < 0.01). With our method ,
image noise was reduced by 20...
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.
Feasibility of low-dose coronary CT angiography: first experience with prospective ECG-gating.
European heart journal.
Accuracy of low-dose computed tomography coronary angiography using prospective electrocardiogram-triggering: first clinical experience.
European heart journal.
Radiation-reduction strategies in...
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