Second-generation motion correction algorithm improves diagnostic accuracy of single-beat coronary CT angiography in patients with increased heart rate.

OBJECTIVE: To assess the effect of a second-generation motion correction algorithm on the diagnostic accuracy of coronary computed tomography angiography (CCTA) using a 256-detector row CT in patients with increased heart rates. METHODS: Eighty-one consecutive symptomatic cardiac patients with increased heart rates (≥ 75 beats per min) were enrolled. All patients underwent CCTA and invasive coronary angiography (ICA). CCTA was performed with a 256-detector row CT using prospectively ECG-triggered single-beat protocol. Images were reconstructed using standard (STD) algorithm, first-generation intra-cycle motion correction (MC1) algorithm, and second-generation intra-cycle motion correction (MC2) algorithm. The image quality of coronary artery segments was assessed by two experienced radiologists using a 4-point scale (1: non-diagnostic and 4: excellent), according to the 18-segment model. Diagnostic performance for segments with significant lumen stenosis (≥ 50%) was compared between STD, MC1, and MC2 by using ICA as the reference standard. RESULTS: The mean effective dose of CCTA was 1.0 mSv. On per-segment level, the overall image quality score and interpretability were improved to 3.56 ± 0.63 and 99.2% due to the use of MC2, as compared to 2.81 ± 0.85 and 92.5% with STD and 3.21 ± 0.79 and 97.2% with MC1. On per-segment level, compared to STD and MC1, MC2 improved the sensitivity (92.2% vs. 79.2%, 80.7%), specificity (97.8% vs. 82.1%, 90.8%), positive predictive value (89.9% vs. 48.4%, 65.1%), negative predictive value (98.3% vs. 94.9%, 95.7%), and diagnostic accuracy (96.8% vs. 81.5%, 89.0%). CONCLUSION: A second-generation intra-cycle motion correction algorithm for single-beat CCTA significantly improves image quality and diagnostic accuracy in patients with increased heart rate. KEY POINTS: • A second-generation motion correction (MC2) algorithm can further improve the image quality of all coronary arteries than a first-generation motion correction (MC1). • MC2 algorithm can significantly reduce the number of false positive segments compared to standard and MC1 algorithm.

A Preliminary Study of Computed Tomography Coronary Angiography Within a Single Cardiac Cycle in Patients With Atrial Fibrillation Using 256-Row Detector Computed Tomography.

OBJECTIVE: The purpose of this study was to evaluate the image quality and radiation dose of computed tomography (CT) coronary angiography using a 256-row detector CT scanner in a single cardiac cycle in patients with atrial fibrillation (AF). METHODS: Seventy consecutive patients (41 men and 29 women; age range was from 37 to 84 years, mean age was 61.7 ± 10.2 years; body mass index range was from 15.08 to 36.45 kg/m, mean body mass index was 25.9 ± 3.5 kg/m) with persistent or paroxysmal AF during acquisition, who were not receiving any medications for heart rate (HR) regulation, were imaged with a 256-row detector CT scanner (Revolution CT, GE healthcare). According to the HR or HR variability (HRV) the patients were divided into 4 groups: group A (HR, ≥75 bpm; n = 36), group B (HR, <75 bpm; n = 34), group C (HRV, ≥50 bpm; n = 26), and group D (HRV, <50 bpm; n = 44). The snapshot freeze algorithm reconstruction was used to reduce motion artifacts whenever necessary. Two experienced radiologists, who were blinded to the electrocardiograph and reconstruction information, independently graded the CT images in terms of visibility and artifacts with a 4-grade rating scale (1, excellent; 2, good; 3, poor; 4, insufficient) using the 18-segment model. Subjective image quality scores and effective dose (ED) were calculated and compared between these groups. RESULTS: The HR during acquisition ranged from 47 to 222 bpm (88.24 ± 36.80 bpm). A total of 917 in 936 coronary artery segments were rated as diagnostically evaluable (98.2 ± 0.04%). There was no significant linear correlation between mean image quality and HR or HRV (P > 0.05). Snapshot freeze reconstruction technique was applied in 28 patients to reduce motion artifacts and thus showed image quality was improved from 93.2% to 98.4%. The ED was 3.05 ± 2.23 mSv (0.49-11.86 mSv) for all patients, and 3.76 ± 2.22 mSv (0.92-11.17 mSv), 2.30 ± 2.02 mSv (0.49-11.86 mSv), 3.89 ± 2.35 mSv (1.18-11.86 mSv), and 2.56 ± 2.03 mSv (0.49-11.17 mSv) for groups A, B, C, and D, respectively. There were significant differences in mean ED between groups A and B, as well as C and D (P <0.05). CONCLUSIONS: This study shows that CT coronary angiography with use of a new 256-row detector CT in single cardiac cycle achieves diagnostic image quality but with lower radiation dose in patients with AF. Heart rate or HRV has no significant effect on image quality.

Impact of SSF on Diagnostic Performance of Coronary Computed Tomography Angiography Within 1 Heart Beat in Patients With High Heart Rate Using a 256-Row Detector Computed Tomography.

OBJECTIVE: The aim of this study was to investigate the impact of a motion-correction algorithm on diagnostic accuracy of coronary computed tomography angiography (CCTA) within 1 heart beat in patients with high heart rate (HR) using a 256-row detector CT. METHOD: Sixty-four consecutive patients with known or suspected coronary artery disease (symptomatic) and with HR of 75 beats per minute or greater (mean [SD] HR, 82.6 [7.3] beats per minute) undergoing CCTA and invasive coronary angiography within 4 weeks were prospectively enrolled. Coronary computed tomography angiography was performed with a 256-row detector CT (Revolution CT, GE Healthcare) using prospectively electrocardiography-triggered volume scan in 1 heart beat. All images were reconstructed using standard (STD) algorithm and a motion-correction algorithm reconstruction (Snapshot Freeze SSF; GE Healthcare) technique. The image quality of coronary artery segments was evaluated by 2 experienced radiologists using a 4-point scale based on the 18-segment model. Diagnostic accuracy was compared between STD and SSF for significant lumen stenosis (≥50%) of each segment with invasive coronary angiography as the reference standard for determining significant stenosis. RESULTS: The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value with STD and SSF were 93.7%, 85.1%, 50.2%, and 98.8% versus 91.9%, 95.8%, 77.9%, and 98.7% on per-segment assessment; 98.7%, 74.0%, 62.9%, and 99.2% versus 96.2%, 94.4%, 77.9%, and 98.7% on per-artery assessment; and 100%, 14.3%, 70.5%, and 100% versus 100%, 85.7%, 93.5%, and 100% on per-patient assessment, respectively. There was a significant difference in accuracy between STD and SFF on per-patient level 71.9% versus 95.3%, on per-artery level 81.6% versus 94.9%, and per-segment level 86.3% versus 95.3%, respectively. The area under receiver operating characteristics curve analysis also showed a significant improvement on diagnostic performance with the SSF technique versus with the STD algorithm on per-patient level (P < 0.001), with corresponding area under the curve being 0.91 (95% confidence interval, 0.79-1.00) and 0.60 (95% confidence interval, 0.44-0.75). The mean effective dose was 2.0 mSv. CONCLUSIONS: Coronary computed tomography angiography can be performed in patients with high HR within 1 heart beat yielding low radiation dose. The use of SSF technique reconstruction for 1 heart beat CCTA achieves significant improvements in image quality and diagnostic value.

Clinical evaluation of new automatic coronary-specific best cardiac phase selection algorithm for single-beat coronary CT angiography.

The aim of this study was to evaluate the workflow efficiency of a new automatic coronary-specific reconstruction technique (Smart Phase, GE Healthcare-SP) for selection of the best cardiac phase with least coronary motion when compared with expert manual selection (MS) of best phase in patients with high heart rate. A total of 46 patients with heart rates above 75 bpm who underwent single beat coronary computed tomography angiography (CCTA) were enrolled in this study. CCTA of all subjects were performed on a 256-detector row CT scanner (Revolution CT, GE Healthcare, Waukesha, Wisconsin, US). With the SP technique, the acquired phase range was automatically searched in 2% phase intervals during the reconstruction process to determine the optimal phase for coronary assessment, while for routine expert MS, reconstructions were performed at 5% intervals and a best phase was manually determined. The reconstruction and review times were recorded to measure the workflow efficiency for each method. Two reviewers subjectively assessed image quality for each coronary artery in the MS and SP reconstruction volumes using a 4-point grading scale. The average HR of the enrolled patients was 91.1±19.0bpm. A total of 204 vessels were assessed. The subjective image quality using SP was comparable to that of the MS, 1.45±0.85 vs 1.43±0.81 respectively (p = 0.88). The average time was 246 seconds for the manual best phase selection, and 98 seconds for the SP selection, resulting in average time saving of 148 seconds (60%) with use of the SP algorithm. The coronary specific automatic cardiac best phase selection technique (Smart Phase) improves clinical workflow in high heart rate patients and provides image quality comparable with manual cardiac best phase selection. Reconstruction of single-beat CCTA exams with SP can benefit the users with less experienced in CCTA image interpretation.