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Preliminary study of prospective ECG-gated 320-detector CT coronary angiography in patients with ventricular premature beats.

Zhang T, Bai J, Wang W, Wang D, Shen B - PLoS ONE (2012)

Bottom Line: In the control group these values were found to be 95.79%, 98.42%, 90.11%, and 99.28% respectively.The two groups had no significant difference in image quality score (P>0.05).For patients with slow heart rates and good rhythm, there was no statistically significant difference in image quality.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China.

ABSTRACT

Background: To study the applicability of prospective ECG-gated 320-detector CT coronary angiography (CTCA) in patients with ventricular premature beats (VPB), and determine the scanning mode that best maximizes image quality and reduces radiation dose.

Methods: 110 patients were divided into a VPB group (60 cases) and a control group (50 cases) using CTCA. All the patients then underwent coronary angiography (CAG) within one month. CAG served as a reference standard through which the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CTCA in diagnosing significant coronary artery stenosis (luminal stenosis ≥50%) could be analyzed. The two radiologists with more than 3 years' experience in cardiac CT each finished the image analysis after consultation. A personalized scanning mode was adopted to compare image quality and radiation dose between the two groups.

Methodology/principal findings: At the coronary artery segment level, sensitivity, specificity, PPV, and NPV in the premature beat group were 92.55%, 98.21%, 88.51%, and 98.72% respectively. In the control group these values were found to be 95.79%, 98.42%, 90.11%, and 99.28% respectively. Between the two groups, specificity, sensitivity PPV, NPV was no significant difference. The two groups had no significant difference in image quality score (P>0.05). Heart rate (77.20±12.07 bpm) and radiation dose (14.62±1.37 mSv) in the premature beat group were higher than heart rate (58.72±4.73 bpm) and radiation dose (3.08±2.35 mSv) in the control group. In theVPB group, the radiation dose (34.55±7.12 mSv) for S-field scanning was significantly higher than the radiation dose (15.10±1.12 mSv) for M-field scanning.

Conclusions/significance: With prospective ECG-gated scanning for VPB, the diagnostic accuracy of coronary artery stenosis is very high. Scanning field adjustment can reduce radiation dose while maintaining good image quality. For patients with slow heart rates and good rhythm, there was no statistically significant difference in image quality.

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Related in: MedlinePlus

Two patients with ventricular premature beats.Figure A shows that heart rate is 71 bpm, 2-beat scanning is adopted, and acquisition is at 30–80% of R-R interval. A premature beat is encountered at the second beat during scanning. The scanning does not stop, and continuously scans the next R-R interval. Figure C shows the heart rate to be 55 bpm, 1-beat scanning is adopted, and acquisition at is 70–80% of R-R interval. Scanning is stopped immediately when a premature beat in encountered, and the scan is resumed at the next normal cardiac cycle. Figures B and D show the ECG-edit of A and C respectively.
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pone-0038430-g003: Two patients with ventricular premature beats.Figure A shows that heart rate is 71 bpm, 2-beat scanning is adopted, and acquisition is at 30–80% of R-R interval. A premature beat is encountered at the second beat during scanning. The scanning does not stop, and continuously scans the next R-R interval. Figure C shows the heart rate to be 55 bpm, 1-beat scanning is adopted, and acquisition at is 70–80% of R-R interval. Scanning is stopped immediately when a premature beat in encountered, and the scan is resumed at the next normal cardiac cycle. Figures B and D show the ECG-edit of A and C respectively.

Mentions: Along with the rapid development of multi-detector spiral CT, 320-detector (640-slice) spiral CT can be seen as the highest level of multi-detector CT. A single scan can cover the whole heart, avoiding the stair-step artifacts that are associated with in 64-detector CT. In addition to the reconstruction of more accurate 3D images [12] and CTA images with higher spatial resolution [13], it also allows for some high-tech applications. For example, arrhythmia scanning software can intelligently identify premature beats, and when checking subjects with premature beats, the software can maximize image quality while reducing radiation dose. If ventricular premature beats are encountered when scanning the first R-R interval, the equipment will automatically stop scanning and collect data at the next period phase. If ventricular premature beats are encountered when scanning R-R intervals after the second interval, the equipment will continue scanning until the end of the next R-R interval (Figure 3). It is very important to ventricular premature beats, and they are abnormal in only one cardiac cycle, so by omitting the R-R interval with premature beat and scanning normal R-R intervals, the necessary period phase intervals can be collected. This is especially important for patients with heart rates below 65 bpm. This is because when a person’s heart rate is below 65 bpm, the equipment will collect a 70%–80% interval of a cardiac cycle. If scanning cannot be stopped during this period, the interval collected would not truly represent 70%–80% of a cardiac cycle. As a consequence, high-quality images cannot be reconstructed. However, 320-slice CT can automatically collect the data from 30%–80% of the next cardiac cycle, thereby avoiding scanning failure and ensuring high image quality.


Preliminary study of prospective ECG-gated 320-detector CT coronary angiography in patients with ventricular premature beats.

Zhang T, Bai J, Wang W, Wang D, Shen B - PLoS ONE (2012)

Two patients with ventricular premature beats.Figure A shows that heart rate is 71 bpm, 2-beat scanning is adopted, and acquisition is at 30–80% of R-R interval. A premature beat is encountered at the second beat during scanning. The scanning does not stop, and continuously scans the next R-R interval. Figure C shows the heart rate to be 55 bpm, 1-beat scanning is adopted, and acquisition at is 70–80% of R-R interval. Scanning is stopped immediately when a premature beat in encountered, and the scan is resumed at the next normal cardiac cycle. Figures B and D show the ECG-edit of A and C respectively.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3368870&req=5

pone-0038430-g003: Two patients with ventricular premature beats.Figure A shows that heart rate is 71 bpm, 2-beat scanning is adopted, and acquisition is at 30–80% of R-R interval. A premature beat is encountered at the second beat during scanning. The scanning does not stop, and continuously scans the next R-R interval. Figure C shows the heart rate to be 55 bpm, 1-beat scanning is adopted, and acquisition at is 70–80% of R-R interval. Scanning is stopped immediately when a premature beat in encountered, and the scan is resumed at the next normal cardiac cycle. Figures B and D show the ECG-edit of A and C respectively.
Mentions: Along with the rapid development of multi-detector spiral CT, 320-detector (640-slice) spiral CT can be seen as the highest level of multi-detector CT. A single scan can cover the whole heart, avoiding the stair-step artifacts that are associated with in 64-detector CT. In addition to the reconstruction of more accurate 3D images [12] and CTA images with higher spatial resolution [13], it also allows for some high-tech applications. For example, arrhythmia scanning software can intelligently identify premature beats, and when checking subjects with premature beats, the software can maximize image quality while reducing radiation dose. If ventricular premature beats are encountered when scanning the first R-R interval, the equipment will automatically stop scanning and collect data at the next period phase. If ventricular premature beats are encountered when scanning R-R intervals after the second interval, the equipment will continue scanning until the end of the next R-R interval (Figure 3). It is very important to ventricular premature beats, and they are abnormal in only one cardiac cycle, so by omitting the R-R interval with premature beat and scanning normal R-R intervals, the necessary period phase intervals can be collected. This is especially important for patients with heart rates below 65 bpm. This is because when a person’s heart rate is below 65 bpm, the equipment will collect a 70%–80% interval of a cardiac cycle. If scanning cannot be stopped during this period, the interval collected would not truly represent 70%–80% of a cardiac cycle. As a consequence, high-quality images cannot be reconstructed. However, 320-slice CT can automatically collect the data from 30%–80% of the next cardiac cycle, thereby avoiding scanning failure and ensuring high image quality.

Bottom Line: In the control group these values were found to be 95.79%, 98.42%, 90.11%, and 99.28% respectively.The two groups had no significant difference in image quality score (P>0.05).For patients with slow heart rates and good rhythm, there was no statistically significant difference in image quality.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China.

ABSTRACT

Background: To study the applicability of prospective ECG-gated 320-detector CT coronary angiography (CTCA) in patients with ventricular premature beats (VPB), and determine the scanning mode that best maximizes image quality and reduces radiation dose.

Methods: 110 patients were divided into a VPB group (60 cases) and a control group (50 cases) using CTCA. All the patients then underwent coronary angiography (CAG) within one month. CAG served as a reference standard through which the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CTCA in diagnosing significant coronary artery stenosis (luminal stenosis ≥50%) could be analyzed. The two radiologists with more than 3 years' experience in cardiac CT each finished the image analysis after consultation. A personalized scanning mode was adopted to compare image quality and radiation dose between the two groups.

Methodology/principal findings: At the coronary artery segment level, sensitivity, specificity, PPV, and NPV in the premature beat group were 92.55%, 98.21%, 88.51%, and 98.72% respectively. In the control group these values were found to be 95.79%, 98.42%, 90.11%, and 99.28% respectively. Between the two groups, specificity, sensitivity PPV, NPV was no significant difference. The two groups had no significant difference in image quality score (P>0.05). Heart rate (77.20±12.07 bpm) and radiation dose (14.62±1.37 mSv) in the premature beat group were higher than heart rate (58.72±4.73 bpm) and radiation dose (3.08±2.35 mSv) in the control group. In theVPB group, the radiation dose (34.55±7.12 mSv) for S-field scanning was significantly higher than the radiation dose (15.10±1.12 mSv) for M-field scanning.

Conclusions/significance: With prospective ECG-gated scanning for VPB, the diagnostic accuracy of coronary artery stenosis is very high. Scanning field adjustment can reduce radiation dose while maintaining good image quality. For patients with slow heart rates and good rhythm, there was no statistically significant difference in image quality.

Show MeSH
Related in: MedlinePlus