Optimizing Coronary Computed Tomography Angiography Using a Novel Deep Learning-Based Algorithm.

Coronary computed tomography angiography (CCTA) is an essential part of the diagnosis of chronic coronary syndrome (CCS) in patients with low-to-intermediate pre-test probability. The minimum technical requirement is 64-row multidetector CT (64-MDCT), which is still frequently used, although it is prone to motion artifacts because of its limited temporal resolution and z-coverage. In this study, we evaluate the potential of a deep-learning-based motion correction algorithm (MCA) to eliminate these motion artifacts. 124 64-MDCT-acquired CCTA examinations with at least minor motion artifacts were included. Images were reconstructed using a conventional reconstruction algorithm (CA) and a MCA. Image quality (IQ), according to a 5-point Likert score, was evaluated per-segment, per-artery, and per-patient and was correlated with potentially disturbing factors (heart rate (HR), intra-cycle HR changes, BMI, age, and sex). Comparison was done by Wilcoxon-Signed-Rank test, and correlation by Spearman's Rho. Per-patient, insufficient IQ decreased by 5.26%, and sufficient IQ increased by 9.66% with MCA. Per-artery, insufficient IQ of the right coronary artery (RCA) decreased by 18.18%, and sufficient IQ increased by 27.27%. Per-segment, insufficient IQ in segments 1 and 2 decreased by 11.51% and 24.78%, respectively, and sufficient IQ increased by 10.62% and 18.58%, respectively. Total artifacts per-artery decreased in the RCA from 3.11 ± 1.65 to 2.26 ± 1.52. HR dependence of RCA IQ decreased to intermediate correlation in images with MCA reconstruction. The applied MCA improves the IQ of 64-MDCT-acquired images and reduces the influence of HR on IQ, increasing 64-MDCT validity in the diagnosis of CCS.

Influence of a new motion correction algorithm (CardioCapture) on the correlation between heart rate and optimal reconstruction phase.

Purpose: To investigate the effect of a new motion correction algorithm (CardioCapture) on the correlation between heart rate and optimal reconstruction phase by evaluating the impact of wide detector CT combined with CardioCapture on CCTA image quality. Materials and methods: All cases were examined from April 2021 to September 2021. Two experienced radiologists scored these images on a four-point Likert scale. First, all images were divided into eight groups according to HR (at an interval of 5 bpm). The subjective score of images, the frequency of used CardioCapture, and the proportion of the diastolic reconstruction phase were compared in each group. Then, all cases were divided into two groups, one group was reconstructed using the automatic temporal reconstruction algorithm (Ephase) only, and the other group was reconstructed using the Ephase with the CardioCapture. The relationship between HR and the diastolic reconstruction phase was analyzed by the receiver operator characteristic curve (ROC). Result: The data of 515 patients were studied. With the increase in HR, the subjective image score decreased, the frequency of CardioCapture increased, and the phase ratio of diastolic reconstruction decreased. When the HR was less than 70 bpm, the percentage of excellence image in each group surpassed 94.90%. The highest utilization rate of CardioCapture was 65.22%, and the lowest proportion of diastolic reconstruction was 72.46%. When 70 bpm < HR ≤ 75 bpm, the image excellence rate was 90.43%, the CardioCapture utilization rate was 82.05%, and the diastolic reconstruction rate was 56.41%.When 75 bpm < HR ≤ 80 bpm, the image excellence rate was 87.91%, the CardioCapture utilization rate was 80.65%, and the diastolic reconstruction was 6.45%.When the HR > 80 bpm, the image excellence rate was 80.00%, the CardioCapture utilization rate was 75.00%, and the diastolic reconstruction rate was 22.50%. The best cut-off point between HR and the diastolic reconstruction ROC curve in the groups without CardioCapture was 65 bpm, while that in groups with CardioCapture was 68 bpm. Conclusion: The CardioCapture can effectively improve the image quality of CCTA with high HR. By maintaining the HR below 68 bpm and utilizing the prospective ECG-gated narrow phase axial scan, it is possible to ensure optimal image quality and concurrently reduce radiation dose.

Effectuality study of a 3D motion correction algorithm in C-arm CTs of severely impaired image quality during transarterial chemoembolization.

BACKGROUND: To evaluate effectivity of a 3D-motion correction algorithm in C-Arm CTs (CACT) with limited image quality (IQ) during transarterial chemoembolization (TACE). METHODS: From 1/2015-5/2021, 644 CACTs were performed in patients during TACE. Of these, 27 CACTs in 26 patients (18 m, 8f; 69.7 years ± 10.7 SD) of limited IQ were included. Post-processing of the original raw-data sets (CACTOrg) included application of a 3D-motion correction algorithm and bone segmentation (CACTMC_no_bone). Four radiologists (R1-4) compared the images by choosing their preferred dataset and recommending repeat acquisition in case of severe IQ-impairment. R1,2 performed additional grading of intrahepatic vessel visualization, presence/extent of movement artifacts, and overall IQ. RESULTS: R1,2 demonstrated excellent interobserver agreement for overall IQ (ICC 0.79,p < 0.01) and the five-point vessel visualization scale before and after post-processing of the datasets (ICC 0.78,p < 0.01). Post-processing caused significant improvement, with overall IQ improving from 2.63 (CACTOrg) to 1.39 (CACTMC_no_bone;p < 0.01) and a decrease in the mean distance of identifiable, subcapsular vessels to the liver capsule by 4 mm (p < 0.01). This proved especially true for datasets with low parenchymal and high hepatic artery contrast. A good interobserver agreement (ICC = 0.73) was recorded concerning the presence of motion artifacts, with significantly less discernible motion after post-processing (CACTOrg:1.31 ± 1.67, CACTMC_no_bone:1.00 ± 1.34, p < 0.01). Of the 27 datasets, ≥ 23 CACTMC_no_bone were preferred, with identical datasets chosen by the readers to show benefit from the algorithm. CONCLUSION: Application of a 3D-motion correction algorithm significantly improved IQ in diagnostically limited CACTs during TACE, with the potential to decrease repeat acquisitions.

Influence of Heart Rate and Innovative Motion-Correction Algorithm on Coronary Artery Image Quality and Measurement Accuracy Using 256-Detector Row Computed Tomography Scanner: Phantom Study.

Objective: To investigate the efficacy of motion-correction algorithm (MCA) in improving coronary artery image quality and measurement accuracy using an anthropomorphic dynamic heart phantom and 256-detector row computed tomography (CT) scanner. Materials and Methods: An anthropomorphic dynamic heart phantom was scanned under a static condition and under heart rate (HR) simulation of 50-120 beats per minute (bpm), and the obtained images were reconstructed using conventional algorithm (CA) and MCA. We compared the subjective image quality of coronary arteries using a four-point scale (1, excellent; 2, good; 3, fair; 4, poor) and measurement accuracy using measurement errors of the minimal luminal diameter (MLD) and minimal luminal area (MLA). Results: Compared with CA, MCA significantly improved the subjective image quality at HRs of 110 bpm (1.3 ± 0.3 vs. 1.9 ± 0.8, p = 0.003) and 120 bpm (1.7 ± 0.7 vs. 2.3 ± 0.6, p = 0.006). The measurement error of MLD significantly decreased on using MCA at 110 bpm (11.7 ± 5.9% vs. 18.4 ± 9.4%, p = 0.013) and 120 bpm (10.0 ± 7.3% vs. 25.0 ± 16.5%, p = 0.013). The measurement error of the MLA was also reduced using MCA at 110 bpm (19.2 ± 28.1% vs. 26.4 ± 21.6%, p = 0.028) and 120 bpm (17.9 ± 17.7% vs. 34.8 ± 19.6%, p = 0.018). Conclusion: Motion-correction algorithm can improve the coronary artery image quality and measurement accuracy at a high HR using an anthropomorphic dynamic heart phantom and 256-detector row CT scanner.

Effect of a Novel Intracycle Motion Correction Algorithm on Dual-Energy Spectral Coronary CT Angiography: A Study with Pulsating Coronary Artery Phantom at High Heart Rates.

OBJECTIVE: Using a pulsating coronary artery phantom at high heart rate settings, we investigated the efficacy of a motion correction algorithm (MCA) to improve the image quality in dual-energy spectral coronary CT angiography (CCTA). MATERIALS AND METHODS: Coronary flow phantoms were scanned at heart rates of 60-100 beats/min at 10-beats/min increments, using dual-energy spectral CT mode. Virtual monochromatic images were reconstructed from 50 to 90 keV at 10-keV increments. Two blinded observers assessed image quality using a 4-point Likert Scale (1 = non-diagnostic, 4 = excellent) and the fraction of interpretable segments using MCA versus conventional algorithm (CA). Comparison of variables was performed with the Wilcoxon rank sum test and McNemar test. RESULTS: At heart rates of 70, 80, 90, and 100 beats/min, images with MCA were rated as higher image scores compared to those with CA on monochromatic levels of 50, 60, and 70 keV (each p < 0.05). Meanwhile, at a heart rate of 90 beats/min, image interpretability was improved by MCA at a monochromatic level of 60 keV (p < 0.05) and 70 keV (p < 0.05). At a heart rate of 100 beats/min, image interpretability was improved by MCA at monochromatic levels of 50 keV (from 69.4% to 86.1%, p < 0.05), 60 keV (from 55.6% to 83.3%, p < 0.05) and 70 keV (from 33.3% to 69.3%, p < 0.05). CONCLUSION: Low-keV monochromatic images combined with MCA improves image quality and image interpretability in CCTAs at high heart rates.

Impact of a motion correction algorithm on image quality in patients undergoing CT angiography: A randomized controlled trial.

AIMS: To investigate the motion correction algorithm Snapshot-Freeze (SSF) compared to standard reconstruction (STD) in patients randomized to receive beta-blockers (BB) or no beta-blockers (non-BB) before coronary CT, and to investigate if SSF can replace BB. METHODS: One hundred and forty patients scheduled for coronary CT were randomized. All images were reconstructed by the SSF and STD algorithms. Image quality was evaluated according to Likert score (1: excellent, 2: good, 3: adequate, 4: non-diagnostic) and presence of artifacts was noted. RESULTS: Images from 64 patients in the BB group (mean HR 56±4bpm) and 51 patients in the non-BB group (mean HR 67±7bpm) were analyzed. Twenty five patients were excluded because of tachycardia, bradycardia or reconstruction errors in SSF. SSF increased the number of excellent images in both groups compared to the STD algorithm (BB: 59% vs.44%; non-BB: 25% vs. 8%), but the number of non-diagnostic images was not significantly reduced. SSF reduced motion artifacts (BB: 11% vs. 31%; non-BB: 49% vs. 75%), but despite this reduction, motion artifacts in non-BB were still more frequent compared to the BB group analyzed by STD (49% vs. 31%). CONCLUSION: SSF improves image quality and reduces motion artifacts, but does not compensate for the absence of BB.

The effect of a whole heart motion-correction algorithm on CT image quality and measurement reproducibility in Pre-TAVR aortic annulus evaluation.

BACKGROUND: Motion correction (MC) algorithms have been shown to improve image quality, interpretability and diagnostic accuracy in coronary CT angiography. We sought to determine whether MC extended to the whole heart would demonstrate improved image quality and reproducibility of aortic annular measurements in pre-TAVR CT. MATERIALS AND METHODS: Twenty-two consecutive contrast enhanced CT data sets acquired for pre TAVR evaluation using retrospective ECG synchronization during a single heart beat were retrospectively identified. Image data sets were obtained from raw data acquired at 35% and 75% of the R-R interval using both standard (STD) and motion corrected (MC) reconstruction algorithms. Four data sets (2 STD, 2 MC) per patient were analyzed by 2 independent, blinded readers for aortic annular area, short and long axis, perimeter and average diameter. Image quality was graded using a 5 point Likert score (1 and 2 non diagnostic, 5 excellent). Statistical analysis was performed using Wilcoxon matched paired tests, Bland-Altman (B-A) plots and Lin's concordance coefficient comparing 35% STD to 35% MC, and 75% STD to 75% MC. RESULTS: Eighty-eight datasets were analyzed (44 STD, 44 MC). At 35%, there was a significant improvement in image quality for MC (Likert score 3.3 ± 0.9 STD vs. 3.9 ± 0.7 MC, p < 0.007). While B-A analysis demonstrated narrower interobserver agreement for aortic annular area (bias 0.03 vs 0.02 cm(2), range -0.32 to 0.39 cm(2) vs -0.50 to 0.55 cm(2)), and perimeter (bias 0.3 vs 0.3 mm, range -3.1 to 3.8 mm vs -4.6 to 5.3 mm), this was not statistically significant by concordance correlation coefficient. At 75%, there was no significant difference in image quality (Likert score 3.3 ± 0.9 vs. 3.5 ± 0.76, p = 0.454) or annular measurement agreement intervals. CONCLUSION: Motion correction algorithms may yield significant improvements of image quality in systolic CT data sets of the heart. Further validation studies are required to determine the effect on annular measurements and translation into clinical practice.

Impact of a motion correction algorithm on quality and diagnostic utility in unselected patients undergoing coronary CT angiography.

AIMS: The aims of the study were to investigate the diagnostic utility of motion correction reconstruction algorithm Snapshot Freeze (SSF) compared to the standard reconstruction algorithm (STD) in coronary computed tomography angiography (CCTA) images where a prescan heart-rate-lowering protocol is fully integrated. METHODS: CCTA was performed in 140 patients. Two independent blinded readers made image evaluation of the SSF and STD images. RESULTS: SSF reduced the motion artifacts (30% vs. 41%; P<.05) and improved the image quality ("excellent" images: 52% vs. 42%; P=.022), but did not influence diagnostic utility ("nondiagnostic" images: 10% vs. 14%; P=.104). CONCLUSION: The use of the SSF algorithm reduced the presence of motion artifacts and improved image quality, but did not influence the diagnostic utility.

Impact of an intra-cycle motion correction algorithm on overall evaluability and diagnostic accuracy of computed tomography coronary angiography.

OBJECTIVES: The aim of this study was to evaluate the impact of a novel intra-cycle motion correction algorithm (MCA) on overall evaluability and diagnostic accuracy of cardiac computed tomography coronary angiography (CCT). METHODS: From a cohort of 900 consecutive patients referred for CCT for suspected coronary artery disease (CAD), we enrolled 160 (18 %) patients (mean age 65.3 ± 11.7 years, 101 male) with at least one coronary segment classified as non-evaluable for motion artefacts. The CCT data sets were evaluated using a standard reconstruction algorithm (SRA) and MCA and compared in terms of subjective image quality, evaluability and diagnostic accuracy. RESULTS: The mean heart rate during the examination was 68.3 ± 9.4 bpm. The MCA showed a higher Likert score (3.1 ± 0.9 vs. 2.5 ± 1.1, p < 0.001) and evaluability (94%vs.79 %, p < 0.001) than the SRA. In a 45-patient subgroup studied by clinically indicated invasive coronary angiography, specificity, positive predictive value and accuracy were higher in MCA vs. SRA in segment-based and vessel-based models, respectively (87%vs.73 %, 50%vs.34 %, 85%vs.73 %, p < 0.001 and 62%vs.28 %, 66%vs.51 % and 75%vs.57 %, p < 0.001). In a patient-based model, MCA showed higher accuracy vs. SCA (93%vs.76 %, p < 0.05). CONCLUSIONS: MCA can significantly improve subjective image quality, overall evaluability and diagnostic accuracy of CCT. KEY POINTS: Cardiac computed tomographic coronary angiography (CCT) allows non-invasive evaluation of coronary arteries. Intra-cycle motion correction algorithm (MCA) allows for compensation of coronary motion. An MCA improves image quality, CCT evaluability and diagnostic accuracy.

Low-dose CT coronary angiography with a novel IntraCycle motion-correction algorithm in patients with high heart rate or heart rate variability.

AIMS: Motion artefacts due to high or irregular heart rate (HR) are common limitations of coronary computed tomography (CT) angiography (CCTA). The aim of the study was to evaluate the impact of a new motion-correction (MC) algorithm used in conjunction with low-dose prospective ECG-triggering CCTA on motion artefacts, image quality, and coronary assessability. METHODS AND RESULTS: Among 380 patients undergoing CCTA for suspected CAD, we selected 120 patients with pre-scanning HR >70 bpm or HR variability (HRv) >10 bpm during scanning irrespective of pre-scanning HR or both conditions. In patients with pre-scanning HR <65 or ≥65 bpm, prospective ECG triggering with padding of 80 ms (58 cases) or padding of 200 ms (62 cases) was used, respectively. Mean pre-scanning HR and HRv were 70 ± 7 and 10.9 ± 4 bpm, respectively. Overall, the mean effective dose was 3.4 ± 1.3 mSv, while a lower dose (2.4 ± 0.9 mSv) was measured for padding of 80 ms. In a segment-based analysis, coronary assessability was significantly higher (P < 0.0001) with MC (97%) when compared with standard (STD) reconstruction (81%) due to a significant reduction (P < 0.0001) in severe artefacts (54 vs. 356 cases, respectively). An artefact sub-analysis showed significantly lower number of motion artefacts and artefacts related to chest movement with MC (16 and 4 cases) than with STD reconstruction (286 and 24 cases, P < 0.0001 and P < 0.05, respectively). The number of coronary segments ranked among those of excellent image quality was significantly higher with MC (P < 0.001). CONCLUSIONS: The MC algorithm improves CCTA image quality and coronary assessability in patients with high HR and HRv, despite low radiation dose.

Heart-rate dependent improvement in image quality and diagnostic accuracy of coronary computed tomographic angiography by novel intracycle motion correction algorithm.

BACKGROUND: To determine the effect of a novel intracycle motion correction algorithm (MCA) on diagnostic accuracy of coronary computed tomographic angiography. METHODS: Coronary artery phantom models were scanned at static and heart rate (HR) simulation of 60-100 beat/min and reconstructed with a conventional algorithm and MCA. RESULTS: Among 144 coronary segments, improvements in image interpretability, quality, and diagnostic accuracy by MCA were observed for HRs of 80 and 100 (P<.05 for all), but not for HR of 60. CONCLUSION: Novel intracycle MCA demonstrates improved HR-dependent image interpretability, and quality and accuracy, particularly at higher HRs.

Effect of a novel motion correction algorithm (SSF) on the image quality of coronary CTA with intermediate heart rates: segment-based and vessel-based analyses.

PURPOSE: To evaluate the effect of SnapShot Freeze (SSF) reconstruction at an intermediate heart-rate (HR) range (65-75bpm) and compare this method with single-sector reconstruction and bi-sector reconstruction on segmental and vessel bases in retrospective coronary computed tomography angiography (CCTA). MATERIALS AND METHODS: Retrospective electrocardiogram-gated CCTA was performed on 37 consecutive patients with HR between 65 and 75bpm using a 64-row CT scanner. Retrospective single-sector reconstruction, bi-sector reconstruction, and SSF were performed for each patient. Multi-phase single-sector reconstruction was performed to select the optimal phase. SSF and bi-sector images were also reconstructed at the optimal phase. The images were interpreted in an intent-to-diagnose fashion by two experienced readers using a 5-point scale, with 3 points as diagnostically acceptable. Image quality among the three reconstruction groups were compared on per-patient, per-vessel, and per-segment bases. RESULTS: The average HR of the enrolled patients was 69.4±2.7bpm. A total of 111 vessels and 481 coronary segments were assessed. SSF provided significantly higher interpretability of the coronary segments than bi-sector reconstructions. The qualified and excellent rates of SSF (97.9% and 82.3%) were significantly higher than those of single-sector (92.9% and 66.3%) and bi-sector (90.9% and 64.7%) reconstructions. The image quality score (IQS) using SSF was also significantly higher than those of single-sector and bi-sector reconstructions both on per-patient and per-vessel bases. On per-segment analysis, IQS was improved in most segments (9/14). CONCLUSION: The SSF algorithm can provide acceptable diagnostic image quality in coronary CTA for patients with intermediate HR.