Multimodality Noninvasive Imaging for Assessment of Congenital Heart Disease

Impact of Appropriate Use Criteria for Cross-Sectional Imaging on Medical Decision-Making in Patients with Conotruncal Defects

Associations between Appropriate Use Criteria (AUC) ratings and medical decision-making in congenital heart disease are not well-established. We applied the 2020 AUC for multimodality imaging in follow-up care of pediatric and young adult patients with conotruncal defects to evaluate appropriateness of cardiac magnetic resonance (CMR) and computed tomography (CCT) use in this population and impact on clinical decision-making. Records were reviewed and assigned AUC indications and corresponding ratings for CMR and CCT. We examined the relationship between AUC indications, their ratings, and change in management. Of the 200 studies (133 CMR, 67 CCT) performed on 187 patients, no studies were rated Rarely Appropriate (R), and most studies were obtained for routine follow-up (151/200 [75.5%]) and were not prompted by clinical concerns. There were 70/200 (35.0%) studies which led to management changes; these included transcatheter intervention (29/70 [41.4%]), surgical intervention (25/70 [35.7%]), other interventions (10/70 [14.3%]), and medical intervention (6/70 [8.6%]). Among all studies, studies prompted by clinical concerns and studies rated M more frequently resulted in change in management (46.9 vs 31.1%, p = 0.04 and 54.1 vs 30.7%, p = 0.003, respectively). In conclusion, we found that all studies were ordered for indications rated Appropriate (A) or May be Appropriate (M), indicating compliance in ordering practices as outlined by published AUC. Studies ordered for clinical change or rated M more frequently led to management change in patient care. Findings may help inform provider expectations of testing yield in this population and serve as a platform for development of future iterations of AUC.

Photon-counting computed tomography for paediatric congenital heart defects yields images of high diagnostic quality with low radiation doses at both 70 kV and 90 kV

BACKGROUND

Photon-counting computed tomography (PCCT) is a new clinical method that may show better diagnostic quality at lower radiation doses than conventional CT.

OBJECTIVE

To investigate the diagnostic quality and radiation dose of paediatric cardiovascular PCCT for diagnosis of congenital heart defects at 70 kV and 90 kV.

MATERIALS AND METHODS

This retrospective assessment included clinical non-gated paediatric PCCT examinations for assessment of congenital heart defects. Radiation doses were recorded, and overall and specific diagnostic quality (1-4) were scored by four paediatric radiologists. Agreement, differences, and trends were assessed by percent rater agreement, intraclass correlation, Mann-Whitney tests, and Jonckheere-Terpstra tests.

RESULTS

Seventy children with congenital heart defects were examined at 70 kV (n = 35; age 2 days-16 years; 63% boys) or 90 kV (n = 35; age 2 days-17 years; 51% boys). All observers gave a median score of 4 (high diagnostic quality) for both 70 kV and 90 kV, with no difference in median values between tube voltages (all P > 0.06). Agreement for overall scores was 66-94% for 70 kV and 60-77% for 90 kV. Agreement for specific scores was 80-97% for 70 kV and 83-89% for 90 kV. Size-dependent dose estimate was 0.68 mGy (0.25-2.02 mGy) for 70 kV and 1.10 mGy (0.58-2.71 mGy; P < 0.001) for 90 kV. Effective dose was 0.30 mSv (0.15-0.82 mSv) for 70 kV and 0.39 mSv (0.22-1.51 mSv; P = 0.01) for 90 kV.

CONCLUSION

Paediatric cardiovascular PCCT yields images for congenital heart defects of high diagnostic quality with low radiation dose at both 70 kV and 90 kV.

Normative Computed Tomography Angiography Values of the Aortic Root, Aorta and Aortic arch in Children

Purpose

Normative values for intracardiac and extracardiac vascular structures help in understanding normal growth and changes over time in children; this normative data are not currently available for ECG-gated Computed Tomography Angiography (CTA). We sought to establish ECG-gated CTA derived normative values for the aortic root, aorta and aortic arch in children.

Methods and Results

Aortic root, ascending aorta, aortic arch, and descending aorta were measured in systole and diastole in 100 subjects who had ECG-gated CTA at our center between January 2015 through December 2020 and met our inclusion criteria. The allometric exponent (AE) for each parameter was derived, and the parameter/body surface areaAE (BSAAE) was established using the previously described methods. Using this data, normalized mean, cross-sectional area, and standard deviation were calculated. Z-score curves were plotted in relation to the BSA for all measurements.

Conclusion

Our study reports systolic and diastolic ECG-gated CTA Z-scores along with normative curves in relation to BSA for the aortic root, aorta and aortic arch in children.

Ambulatory sedation for children under 6 years with CHD in MRI and CT

INTRODUCTION

In infants and young children, good image quality in MRI and CT requires sedation or general anesthesia to prevent motion artefacts. This study aims to determine the safety of ambulatory sedation for children with CHD in an outpatient setting as a feasible alternative to in-hospital management.

METHODS

We recorded 91 consecutive MRI and CT examinations of patients with CHD younger than 6 years with ambulatory sedation. CHD diagnoses, vital signs, applied sedatives, and adverse events during or after ambulatory sedation were investigated.

RESULTS

We analysed 91 patients under 72 months (6 years) of age (median 26.0, range 1-70 months; 36% female). Sixty-eight per cent were classified as ASA IV, 25% as ASA III, and 7% as ASA II (American Society of Anesthesiologists Physical Status Classification). Ambulatory sedation was performed by using midazolam, propofol, and/or S-ketamine. The median sedation time for MRI was 90 minutes (range 35-235 minutes) and 65 minutes for CT (range 40-280 minutes). Two male patients (age 1.5 months, ASA II, and age 17 months, ASA IV) were admitted for in-hospital observation due to unexpected severe airway obstruction. The patients were discharged without sequelae after 1 and 3 days, respectively. All other patients were sent home on the day of examination.

CONCLUSION

In infants and young children with CHD, MRI or CT imaging can be performed under sedation in an outpatient setting by a well-experienced team. In-hospital backup should be available for unexpected events.

Normative computed tomography angiography values of the main and branch pulmonary arteries in children

Non-invasive cardiac imaging like echocardiogram, cardiac magnetic resonance imaging (CMR), and computed tomography angiography (CTA) play a key role in the diagnosis, aid in management and follow-up of congenital heart disease patients. Normative data for intracardiac and extracardiac vascular structures in children are currently available for echocardiogram, CMR, and non-gated CTA. We sought to establish systolic and diastolic normative data for main and branch pulmonary arteries in children using electrocardiogram (ECG)-gated CTA. Diameters and cross-sectional areas of the main and branch pulmonary arteries were measured in systole and diastole based on the aortic valve position (open versus closed) in 100 subjects who had ECG-gated cardiac CTA at our center between January 2015 through December 2020 and met our inclusion criteria. The allometric exponent (AE) for each parameter was derived, and the parameter/body surface area (BSAAE) was established using the previously described methods. A total of 100 children aged 0-18 years were analyzed; mean age was 5.3 years (SD, 6.1 years). Z-score curves were plotted in relation to the BSA for the mean, maximum, and minimum diameters and cross-sectional area of the main and branch pulmonary arteries for systole and diastole.   Conclusion: We report systolic and diastolic mean, maximum, and minimum diameters and cross-sectional areas along with Z-scores and normative curves for the main and branch pulmonary arteries in children derived using ECG-gated cardiac CTA. We believe our results can help identify abnormally sized main and branch pulmonary arteries. What is Known: • Normative data for intracardiac and extracardiac vascular structures in the pediatric population are available for echocardiography, cardiac MRI and non-ECG gated CTA. • Z-scores with standard deviations are commonly used in children, but SDs are not constant across body sizes due to heteroscedasticity. What is New: • Allometric exponent was derived for each parameter and the parameter/body surface area (BSA) was established. • This is the first ECG-gated CTA study to provide normative en face systolic, diastolic diameters and cross-sectional areas along with Z-scores and normative curves for the main and branch pulmonary arteries in children.

Recent Advances in the Diagnosis and Management of Congenital Heart Disease

Congenital heart defects (CHDs) are structural abnormalities of the heart or blood vessels that occur while cardiac structures are being formed in utero [...].

Proposed competencies for the performance of cardiovascular computed tomography in pediatric and adult congenital heart disease

Cardiovascular computed tomography (CCT) is rated appropriate by published guidelines for the initial evaluation and follow up of congenital heart disease (CHD) and is an essential modality in cardiac imaging programs for patients of all ages. However, no recommended core competencies exist to guide CCT in CHD imaging training pathways, curricula development, or establishment of a more formal educational platform. To fill this gap, a group of experienced congenital cardiac imagers, intentionally inclusive of adult and pediatric cardiologists and radiologists, was formed to propose core competencies fundamental to the expert-level performance of CCT in pediatric acquired and congenital heart disease and adult CHD. The 2020 SCCT Guideline for Training Cardiology and Radiology Trainees as Independent Practitioners (Level II) and Advanced Practitioners (Level III) in Cardiovascular Computed Tomography (1) for adult imaging were used as a framework to define pediatric and CHD-specific competencies. Established competencies will be immediately relevant for advanced cardiac imaging fellowships in both cardiology and radiology training pathways. Proposed future steps include radiology and cardiology society collaboration to establish provider certification levels, training case-volume recommendations, and continuing medical education (CME) requirements for expert-level performance of CCT in pediatric and adult CHD.

Feasibility of Wave Intensity Analysis from 4D Cardiovascular Magnetic Resonance Imaging Data

Congenital heart defects (CHD) introduce haemodynamic changes; e.g., bicuspid aortic valve (BAV) presents a turbulent helical flow, which activates aortic pathological processes. Flow quantification is crucial for diagnostics and to plan corrective strategies. Multiple imaging modalities exist, with phase contrast magnetic resonance imaging (PC-MRI) being the current gold standard; however, multiple predetermined site measurements may be required, while 4D MRI allows for measurements of area (A) and velocity (U) in all spatial dimensions, acquiring a single volume and enabling a retrospective analysis at multiple locations. We assessed the feasibility of gathering hemodynamic insight into aortic hemodynamics by means of wave intensity analysis (WIA) derived from 4D MRI. Data were collected in n = 12 BAV patients and n = 7 healthy controls. Following data acquisition, WIA was successfully derived at three planes (ascending, thoracic and descending aorta) in all cases. The values of wave speed were physiological and, while the small sample limited any clinical interpretation of the results, the study shows the possibility of studying wave travel and wave reflection based on 4D MRI. Below, we demonstrate for the first time the feasibility of deriving wave intensity analysis from 4D flow data and open the door to research applications in different cardiovascular scenarios.

Diagnostic accuracy of lower-dose cardiac CT in evaluating young infants with non-coronary complex congenital heart disease on a 64-slice multidetector CT scanner

Background

Redoable precise and non-invasive diagnostic imaging modality with the least radiation dose is essential for infants with congenital heart disease (CHD) .

Purpose

To investigate the accuracy and estimate the radiation dose of our cardiac computed tomography (CCT) protocol.

Material and Methods

A total of 82 infants with CHD underwent non-ECG-gated CCT without contrast timing scanning techniques and were retrospectively studied. The image quality and radiation dose were estimated. The radiation dose was compared statistically to virtual retrospective ECG-gated and prospective ECG-triggering scanning modes. The diagnostic accuracy was assessed assuming the surgical results as the diagnostic gold standard.

Results

Most exams showed a high quality with low radiation doses compared to previous studies. The mean effective dose (ED) was 0.39 ± 1.2, significantly lower than that of the virtual retrospective ECG-gated and prospective ECG-triggering scanning and lower than in previous studies. Our CCT protocol has achieved a diagnostic accuracy of 99.52% with a sensitivity of 94.83% and specificity of 99.91%.

Conclusion

Non-ECG-gated CCT without contrast timing techniques can detect the non-coronary cardiovascular defects of CHD in infants with an ultralow radiation dose and a high diagnostic accuracy.

Cardiac Computed Tomography-Derived Left Atrial Strain and Volume in Pediatric Patients With Congenital Heart Disease: A Comparative Analysis With Transthoracic Echocardiography

Purpose

This study aimed at exploring the feasibility and reproducibility of CCT for the measurement of Left Atrial (LA) strain and volume compared with transthoracic echocardiography (TTE) in pediatric patients with congenital heart disease (CHD).

Materials and Methods

The present study included 43 postoperative patients with CHD (7.39 ± 3.64 years, 56% male) who underwent clinically indicated CCT, and all patients underwent additional TTE on the same day. LA strain and volume parameters were measured by dedicated software. The correlation and agreement of LA strain and volume parameters were assessed using Pearson’s correlation coefficient and Bland-Altman analysis. Intra-class correlation coefficients (ICC) were used to assess CCT intra-observer and inter-observer reproducibility.

Results

All strain parameters of CCT were lower compared to TTE (reservoir strain: 28.37 ± 6.92 vs. 32.15 ± 8.15, respectively; conduit strain: 21.33 ± 6.46 vs. 24.23 ± 7.75, respectively; booster strain: 7.04 ± 2.74 vs. 7.92 ± 3.56). While the volume parameters of CCT were higher compared to TTE (LAV: 29.60 ± 19.01 vs. 25.66 ± 17.60, respectively; LAVi: 30.36 ± 22.31 vs. 28.63 ± 19.25, respectively). Both LA strain and volume measurements showed good correlation and agreement between the two modalities (r = 0.63–0.87, p < 0.001). CT-derived LA strain and volume measurements showed good intra- and inter-observer reproducibility using prototype software (ICC = 0.78–0.96).

Conclusions

CCT was feasible for measuring LA strain and volume with good correlation and high reproducibility as compared with TTE. As a complementary modality, CCT can regard as an accepted method in the evaluation of LA function in pediatric patients with CHD

Recommendations for cardiovascular magnetic resonance and computed tomography in congenital heart disease: a consensus paper from the CMR/CCT working group of the Italian Society of Pediatric Cardiology (SICP) and the Italian College of Cardiac Radiology endorsed by the Italian Society of Medical and Interventional Radiology (SIRM) Part I

Cardiovascular magnetic resonance (CMR) and computed tomography (CCT) are advanced imaging modalities that recently revolutionized the conventional diagnostic approach to congenital heart diseases (CHD), supporting echocardiography and often replacing cardiac catheterization. Nevertheless, correct execution and interpretation require in-depth knowledge of all technical and clinical aspects of CHD, a careful assessment of risks and benefits before each exam, proper imaging protocols to maximize diagnostic information, minimizing harm. This position paper, written by experts from the Working Group of the Italian Society of Pediatric Cardiology and from the Italian College of Cardiac Radiology of the Italian Society of Medical and Interventional Radiology, is intended as a practical guide for applying CCT and CMR in children and adults with CHD, wishing to support Radiologists, Pediatricians, Cardiologists and Cardiac Surgeons in the multimodality diagnostic approach to these patients. The first part provides a review of the most relevant literature in the field, describes each modality's advantage and drawback, making considerations on the main applications, image quality, and safety issues. The second part focuses on clinical indications and appropriateness criteria for CMR and CCT, considering the level of CHD complexity, the clinical and logistic setting and the operator expertise.

Velocity encoded mitral valve inflow cine: A novel and more reproducible method to determine cardiac rest periods during coronary magnetic resonance angiography

A high temporal resolution, 4-chamber (4CH) cine is the standard method for determining cardiac rest periods during whole heart coronary magnetic resonance angiography (CMRA). We evaluated the image quality and reproducibility between the 4CH cine method and a novel approach using a velocity encoded mitral valve inflow cine (MVI). The goal of this study was to compare the quality of CMRAs utilizing MVI versus 4CH methods. Sharpness and vessel length for the LCA and RCA using each method were determined using Soap Bubble and two blinded observers independently assessed coronary image quality. Offline analysis on a separate, retrospective cohort (n = 25) was used to compare MVI and 4CH reproducibility. In the prospectively evaluated cohort there was no difference in overall vessel sharpness (4CH vs MVI mean ± SD) (31.0 ± 5.5% vs 30.5 ± 5.7%, p = .63), LCA vessel sharpness (30.0 ± 5.4% vs 31.1 ± 8.2%, p = .44), LCA length (4.7 ± 1.4 cm vs 4.6 ± 1.6 cm, p = .66), RCA vessel sharpness (32.1 ± 6.9% vs 31.1 ± 7.7%, p = .55), RCA length (5.51 ± 2.6 cm vs 5.95 ± 2.4 cm, p = .38), or image quality rating (2.66 vs 2.62, p = .80) between methods. In the retrospective cohort, the MVI method had 5.4% lower inter-observer variability (95% CI 3.7,7.2%, p < .0001) and 3.9% lower intra-observer variability (95% CI 2.4,5.4%, p < .0001) than the 4CH method.

MVI is a technically feasible and more reproducible method to determine cardiac rest periods compared to 4CH while preserving vessel sharpness, vessel length & image quality.

Cardiac Imaging in Patients After Fontan Palliation: Which Test and When?

The Fontan operation represents the final stage of a series of palliative surgical procedures for children born with complex congenital heart disease, where a "usual" biventricular physiology cannot be restored. The palliation results in the direct connection of the systemic venous returns to the pulmonary arterial circulation without an interposed ventricle. In this unique physiology, systemic venous hypertension and intrathoracic pressures changes due to respiratory mechanics play the main role for propelling blood through the pulmonary vasculature. Although the Fontan operation has dramatically improved survival in patients with a single ventricle congenital heart disease, significant morbidity is still a concern. Patients with Fontan physiology are in fact suffering from a multitude of complications mainly due to the increased systemic venous pressure. Consequently, these patients need close clinical and imaging monitoring, where cardiac exams play a key role. In this article, we review the main cardiac imaging modalities available, summarizing their main strengths and limitations in this peculiar setting. The main purpose is to provide a practical approach for all clinicians involved in the care of these patients, even for those less experienced in cardiac imaging.

Utility of cardiac CT in infants with congenital heart disease: Diagnostic performance and impact on management

BACKGROUND

Advances in cardiac CT (CCT) scanner technology allow imaging without anesthesia, and with low radiation dose, making it an attractive technique in infants with congenital heart disease. However, the utility of CCT using a dual-source scanner with respect to diagnostic performance and impact on management has not been systematically studied in this population.

METHODS

Retrospective review of infants who underwent CCT to determine the utility of CCT with respect to the following: answering the primary diagnostic question, providing new diagnostic information, prompting a change in management, and concordance with catheterization or surgical inspection.

RESULTS

A total of 156 infants underwent 172 scans at a median age of 64 days, (IQR 4-188) from Jan 2016-Dec 2019. The most frequent diagnostic question was related to the pulmonary arteries (43%), followed by the aortic arch (30%), pulmonary veins (26%), coronary arteries (17%), patent ductus arteriosus (10%) and others (9%). A high-pitch spiral scan was frequently used (90%). The median effective radiation dose was low (0.66 ​mSv) and general anesthesia was used infrequently (23%). CCT answered the primary diagnostic question in 168/172 (98%) and added to the diagnostic information already available by echocardiography in 161/172 (96%) scans. CCT led to a change in management following 78/172 (53%) scans and had an impact on management following 167/172 (97%) scans. On follow-up, after 107/172 (62%) scans, subjects underwent cardiac surgery, and after 55/172 (32%) scans, they had cardiac catheterization. CCT findings were concordant with catheterization and/or surgical inspection in 156/159 (98%) scans.

CONCLUSIONS

In infants with complex congenital heart disease, CCT was accurate, answered the diagnostic questions in nearly all cases, and frequently added diagnostic information that impacted management. Radiation exposure was low, and anesthesia was needed infrequently.

Comparison of preoperative trans-thoracic echocardiography with intraoperative findings in patients with congenital heart disease undergoing surgery: a prospective observational study

OBJECTIVE

To determine the diagnostic accuracy and safety of trans-thoracic echocardiography alone for indicating surgery by correlating preoperative trans-thoracic echocardiography with intra-operative findings in patients with congenital heart disease (CHD) in a low resource, low volume center.

METHODOLOGY

The pre-operative trans-thoracic echocardiography and intra-operative findings of two hundred and fifty patients with CHD, undergoing surgery at the National Cardiothoracic Centre (NCTC), Korle Bu Teaching Hospital, from 2012 to 2017 were prospectively compared. Included in this prospective study, were all patients with CHD who had trans-thoracic echocardiography alone at the NCTC. Excluded were patients who were operated at the NCTC based on echocardiography done elsewhere, those who had echocardiography at the NCTC but were operated elsewhere, as well as those whose operative decision were based on cardiac catheterization or CT angiography and patients with acquired heart defects. The analysis included profiling of patients on different demographic and clinical parameters. SPSS software was used for analysis.

RESULTS

Of the 250 patients ages ranged from 2 months to 60 years. The mean was 4 years 95 days, median 1 year 180 days. The female sex accounted for 152 (60.6%). The preoperative trans-thoracic echocardiography correlated with intra-operative findings completely in 228 (91.2%) of patients, affirming the accuracy of this imaging modality. There were however, 19 (7.6%) false negatives and 3 (1.2%) false positive. Neither the false positive nor false negative errors resulted in complications or adversely affected the surgical outcome.

CONCLUSION

Based on the results of this study, preoperative transthoracic echocardiography done by cardiologists at the National Cardiothoracic Center, Korle Bu Teaching Hospital Accra, demonstrated a high correlation with intraoperative findings. Echocardiography also proved to be sensitive, accurate and safe for indicating surgery in patients with congenital heart disease.

Feasibility of Cardiac Computed Tomography for the Evaluation of Ventricular Function in Postoperative Children With Congenital Heart Disease: Comparison With Cardiac Magnetic Resonance Imaging

OBJECTIVE

We explored the feasibility of cardiac computed tomography (CCT) to evaluate postoperative ventricular function in children with congenital heart disease (CHD) and evaluated the accuracy and reproducibility of CCT using cardiac magnetic resonance (CMR) as a reference.

METHODS

Thirty-two postoperative children with CHD (20 boys and 12 girls) who underwent CMR and CCT were enrolled. Left and right ventricular ejection fraction, end-diastolic volume, end-systolic volume, stroke volume, and cardiac index were measured using cardiac function analysis software. Cardiac function data were compared between CMR and CCT. The agreement between the 2 modalities was assessed using a Bland-Altman analysis. Intraclass correlation coefficients were used to assess intraobserver and interobserver reproducibility in CCT functional measurements.

RESULTS

All functional parameters showed no significant difference (P > 0.05) and were well-correlated (r > 0.5, P < 0.05) between CMR and CCT. The mean values of all ventricular function parameters in CCT were higher compared with CMR. As indicated by 95% limits of agreement, left ventricular function parameters showed a better level of agreement compared with right ventricular function parameters between the 2 modalities. Intraobserver and interobserver reproducibility were excellent in CCT measurements for all functional parameters (intraclass correlation coefficient > 0.9).

CONCLUSIONS

Compared with the criterion standard of CMR, CCT is feasible for assessing postoperative ventricular function with sufficient diagnostic accuracy and reproducibility in children with CHD. In addition to its important role regarding anatomical characterization, CCT is a suitable alternative and convenient follow-up tool that can be used to functional evaluation in children who are intolerant with CMR or have contraindications to CMR.

Comparison of echocardiography and 320-row multidetector computed tomography for the diagnosis of congenital heart disease in children

INTRODUCTION

Echocardiography (echo) is the primary non-invasive imaging modality for the assessment of congenital heart disease (CHD). Computed tomography angiography (CTA) also has potential to examine the anatomy of complex heart anomalies as well as extracardiac involvement.

OBJECTIVES

The aim of this study is to determine the impact of new CTA technology in the diagnosis of CHD and to compare echo and CTA in terms of diagnostic accuracy.

METHODS

Forty-five patients who underwent preoperative echo and CTA assessment in the intensive care unit were included in this study. The results were assessed for three main types of CHD (cardiac malformations, cardiac-major vessel connections and major vessels). The main groups were also divided into subgroups according to surgical features in order to assess them more objectively. Imaging methods were compared for diagnostic accuracy, sensitivity and specificity, while surgical findings were accepted as the gold standard.

RESULTS

Patients' median age and weight were two months (three days-eight years) and 12 kg (2.5-60 kg), respectively. In 45 operated cases, 205 subgroup malformations were assessed. Diagnostic accuracy was significantly greater in echo (echo vs. CTA: 98.4% and 96.2% [chi-square=6.4, p=0.011]). During surgery, 84 cardiac malformations (echo vs. CTA: 97.4% and 95.1% [chi-square=4.9, p=0.03]), 47 cardiac-major vessel connections (echo vs. CTA: 98.3% and 95.4% [chi-square=7.5, p=0.03]), and 74 major vessel malformations (echo vs. CTA: 96% and 98% [chi-square=1.8, p=0.48]) were confirmed.

CONCLUSION

Echocardiography and CTA are imaging methods with high diagnostic accuracy in children with CHD. The use of echocardiography together with CTA, especially for the visualization of extracardiac anatomy, provides additional information for clinicians.

Postoperative evaluation of left ventricular global strain using cardiac computed tomography in pediatric patients with congenital heart disease: A comparison with echocardiography

PURPOSE

We explored the feasibility and reproducibility of cardiac computed tomography (CCT)-derived left ventricular (LV) global strain in postoperative children
with congenital heart disease (CHD) and compared its correlation and agreement with transthoracic echocardiography (TTE).

METHODS

Fifty-one patients (28 males, 23 females) were included who underwent clinically indicated retrospective electrocardiography-triggered CCT. and all patients underwent additional TTE on the same day. LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were measured. Correlations of global strains between CCT and TTE were assessed using Pearson's correlation coefficient. Intra-class correlation coefficients (ICC) were used to assess CCT intra-observer and inter-observer reproducibility.

RESULTS

GLS and GCS were not significantly different between CCT and TTE (GLS: -23.54 ± 3.24 vs. -23.85 ± 3.72, respectively, p = 0.415; GCS: -28.21 ± 3.55 vs. -28.79 ± 3.69, respectively, p = 0.155). GRS was significantly different between CCT and TTE (60.79 ± 15.11 vs. 41.73 ± 4.27, respectively, p < 0.001). There was good correlation between CCT- and TTE-derived GLS (r = 0.70, p < 0.001) and GCS (r = 0.68, p < 0.001), but GRS showed no correlation between CCT and TTE (r = 0.09, p = 0.54). CCT-derived global strain showed good intra- and inter-observer reproducibility (ICC = 0.86-0.92), except the inter-observer reproducibility for GRS (ICC = 0.77).

CONCLUSIONS

CCT was feasible for postoperative evaluation of LV global strain in pediatric patients with CHD with sufficient reproducibility. CCT-derived global strain can provide additional information in selected CHD patients with poor acoustic windows and who are intolerant to or have contraindications for cardiac magnetic resonance.

Comparison of echocardiography and 320-row multidetector computed tomography for the diagnosis of congenital heart disease in children

INTRODUCTION

Echocardiography (echo) is the primary non-invasive imaging modality for the assessment of congenital heart disease (CHD). Computed tomography angiography (CTA) also has potential to examine the anatomy of complex heart anomalies as well as extracardiac involvement.

OBJECTIVES

The aim of this study is to determine the impact of new CTA technology in the diagnosis of CHD and to compare echo and CTA in terms of diagnostic accuracy.

METHODS

Forty-five patients who underwent preoperative echo and CTA assessment in the intensive care unit were included in this study. The results were assessed for three main types of CHD (cardiac malformations, cardiac-major vessel connections and major vessels). The main groups were also divided into subgroups according to surgical features in order to assess them more objectively. Imaging methods were compared for diagnostic accuracy, sensitivity and specificity, while surgical findings were accepted as the gold standard.

RESULTS

Patients' median age and weight were two months (three days-eight years) and 12 kg (2.5-60 kg), respectively. In 45 operated cases, 205 subgroup malformations were assessed. Diagnostic accuracy was significantly greater in echo (echo vs. CTA: 98.4% and 96.2% [chi-square=6.4, p=0.011]). During surgery, 84 cardiac malformations (echo vs. CTA: 97.4% and 95.1% [chi-square=4.9, p=0.03]), 47 cardiac-major vessel connections (echo vs. CTA: 98.3% and 95.4% [chi-square=7.5, p=0.03]), and 74 major vessel malformations (echo vs. CTA: 96% and 98% [chi-square=1.8, p=0.48]) were confirmed.

CONCLUSION

Echocardiography and CTA are imaging methods with high diagnostic accuracy in children with CHD. The use of echocardiography together with CTA, especially for the visualization of extracardiac anatomy, provides additional information for clinicians.

Mixed type TAPVR-Measure twice, cut once

Total anomalous pulmonary venous return (TAVR) can have varying drainage configurations. Here, we review a report by Nagulakonda et al. to the Journal of Cardiac Surgery detailing how additional computed tomography imaging revealed a mixed type presentation of TAPVR not identified on echocardiography.

Role of Computed Tomography in Postoperative Follow-up of Arterial Switch Operation

An arterial switch operation (ASO) is the standard treatment for infants and children born with D-loop transposition of the great arteries. During the ASO, the great vessels are transected from the native roots, switched and anastomosed with the opposite roots. This is accompanied by the relocation of the pulmonary artery anterior to the aorta by using the LeCompte maneuver and the translocation of coronary arteries to the neo-aorta. ASO has led to improved overall survival, and postoperative mortality is rare. Despite the improved outcomes, several postoperative sequelae may occur, and therefore patients require long-term follow-up. Computed tomography (CT) has emerged as a robust imaging modality in pre and postoperative evaluation of a variety of congenital heart disorders including ASO. Unlike echocardiography and cardiovascular magnetic resonance, CT is not hindered by a poor acoustic window, metallic devices or the need for sedation or general anesthesia. CT with advanced three-dimensional postprocessing techniques, high pitch scanning, wider detector system, electrocardiogram-dependent modulation and dose-reduction strategies is invaluable in assessing the postoperative complications after ASO.

3D Echocardiography Provides Highly Accurate 3D Printed Models in Congenital Heart Disease

Cardiac 3D printing is mainly performed from magnetic resonance imaging (MRI) and computed tomography (CT) 3D datasets, though anatomic detail of atrioventricular (AV) valves may be limited. 3D echo provides excellent visualization of AV valves. Thus, we tested the feasibility and accuracy of 3D printing from 3D echo in this pilot series of subjects with congenital heart disease (CHD), with a focus on valve anatomy. Five subjects with CHD were identified. 3D echo data were converted to 3D printable files and printed in collaboration with 3D Systems Healthcare (Golden, Colorado). A novel technique for valve modeling was utilized using commercially available software. Two readers (KM, SA) independently measured valve structures from 3D models and compared to source echo images. 3D printing was feasible for all cases. Table 1 shows measurements comparing 2D echo to 3D models. Bland Altman analysis showed close agreement and no significant bias between 2D and digital 3D models (mean difference 0.0, 95% CI 1.1 to - 1.1) or 2D vs printed 3D models, though with wider limits of agreement (mean difference - 0.3, 95% CI 1.9 to - 2.6). Accuracy of 3D models compared to 2D was within < 0.5 mm. This pilot study shows 3D echo datasets can be used to reliably print AV and semilunar valve structures in CHD. The 3D models are highly accurate compared to the source echo images. This is a novel and value-added technique that adds incremental information on cardiac anatomy over current methods.

Retraining Convolutional Neural Networks for Specialized Cardiovascular Imaging Tasks: Lessons from Tetralogy of Fallot

Ventricular contouring of cardiac magnetic resonance imaging is the gold standard for volumetric analysis for repaired tetralogy of Fallot (rTOF), but can be time-consuming and subject to variability. A convolutional neural network (CNN) ventricular contouring algorithm was developed to generate contours for mostly structural normal hearts. We aimed to improve this algorithm for use in rTOF and propose a more comprehensive method of evaluating algorithm performance. We evaluated the performance of a ventricular contouring CNN, that was trained on mostly structurally normal hearts, on rTOF patients. We then created an updated CNN by adding rTOF training cases and evaluated the new algorithm's performance generating contours for both the left and right ventricles (LV and RV) on new testing data. Algorithm performance was evaluated with spatial metrics (Dice Similarity Coefficient (DSC), Hausdorff distance, and average Hausdorff distance) and volumetric comparisons (e.g., differences in RV volumes). The original Mostly Structurally Normal (MSN) algorithm was better at contouring the LV than the RV in patients with rTOF. After retraining the algorithm, the new MSN + rTOF algorithm showed improvements for LV epicardial and RV endocardial contours on testing data to which it was naïve (N = 30; e.g., DSC 0.883 vs. 0.905 for LV epicardium at end diastole, p < 0.0001) and improvements in RV end-diastolic volumetrics (median %error 8.1 vs 11.4, p = 0.0022). Even with a small number of cases, CNN-based contouring for rTOF can be improved. This work should be extended to other forms of congenital heart disease with more extreme structural abnormalities. Aspects of this work have already been implemented in clinical practice, representing rapid clinical translation. The combined use of both spatial and volumetric comparisons yielded insights into algorithm errors.

A Novel Virtual Reality Medical Image Display System for Group Discussions of Congenital Heart Disease: Development and Usability Testing

Background

The complex 3-dimensional (3D) nature of anatomical abnormalities in congenital heart disease (CHD) necessitates multidisciplinary group discussions centered around the review of medical images such as magnetic resonance imaging. Currently, group viewings of medical images are constrained to 2-dimensional (2D) cross-sectional displays of 3D scans. However, 2D display methods could introduce additional challenges since they require physicians to accurately reconstruct the images mentally into 3D anatomies for diagnosis, staging, and planning of surgery or other therapies. Virtual reality (VR) software may enhance diagnosis and care of CHD via 3D visualization of medical images. Yet, present-day VR developments for medicine lack the emphasis on multiuser collaborative environments, and the effect of displays and level of immersion for diagnosing CHDs have not been studied.

Objective

The objective of the study was to evaluate and compare the diagnostic accuracies and preferences of various display systems, including the conventional 2D display and a novel group VR software, in group discussions of CHD.

Methods

A total of 22 medical trainees consisting of 1 first-year, 10 second-year, 4 third-year, and 1 fourth-year residents and 6 medical students, who volunteered for the study, were formed into groups of 4 to 5 participants. Each group discussed three diagnostic cases of CHD with varying structural complexity using conventional 2D display and group VR software. A group VR software, Cardiac Review 3D, was developed by our team using the Unity engine. By using different display hardware, VR was classified into nonimmersive and full-immersive settings. The discussion time, diagnostic accuracy score, and peer assessment were collected to capture the group and individual diagnostic performances. The diagnostic accuracies for each participant were scored by two experienced cardiologists following a predetermined answer rubric. At the end of the study, all participants were provided a survey to rank their preferences of the display systems for performing group medical discussions.

Results

Diagnostic accuracies were highest when groups used the full-immersive VR compared with the conventional and nonimmersive VR (χ²₂=9.0, P=.01) displays. Differences between the display systems were more prominent with increasing case complexity (χ²₂=14.1, P<.001) where full-immersive VR had accuracy scores that were 54.49% and 146.82% higher than conventional and nonimmersive VR, respectively. The diagnostic accuracies provided by the two cardiologists for each participant did not statistically differ from each other (t=–1.01, P=.31). The full-immersive VR was ranked as the most preferred display for performing group CHD discussions by 68% of the participants.

Conclusions

The most preferred display system among medical trainees for visualizing medical images during group diagnostic discussions is full-immersive VR, with a trend toward improved diagnostic accuracy in complex anatomical abnormalities. Immersion is a crucial feature of displays of medical images for diagnostic accuracy in collaborative discussions.

Intermodality agreement between TTE and low kVp ECG-gated MDCTA in diagnosis of complex CHD in pediatrics

Background

Transthoracic echocardiography (TTE) is considered the primary diagnostic modality in congenital heart disease (CHD). However, it has limited role in evaluation of extra-cardiac major vessels abnormalities. Cardiac catheterization angiography is considered the gold standard investigation, yet, it is invasive. The aim of this study is to evaluate the agreement between TTE and low kVp ECG-gated cardiac multi-detector CT angiography (MDCTA) in detecting cardiac and extra-cardiac findings of complex congenital heart disease in a sample size of 36 patients (19 males and 17 females) with an age ranged between 30 days and 12 years (mean age 25.5 months). All cases were diagnosed to have complex CHD clinically and by TTE then referred to undergo cardiac low kVp ECG-gated MDCTA to confirm diagnosis and for better assessment of extra-cardiac major vessels abnormalities. Data derived from both modalities were then compared to calculate the inter-technique variability by using Cohen’s kappa statistics.

Results

TTE diagnosed 96% of intra-cardiac anomalies and only 54% of extra-cardiac major vessels anomalies detected by MDCTA, with variable degrees of intermodality agreement in detection different anomalies ranging between perfect agreement in diagnosing most of intra-cardiac lesions and very poor agreement in diagnosing extra-cardiac SVC anomalies.

Conclusion

Low kVp ECG-gated cardiac MDCTA is a rapid, non-invasive and reliable diagnostic modality in complex congenital heart diseases. It confirms TTE findings in intra-cardiac anomalies and significantly surpasses TTE reliability in diagnosis of extra-cardiac major vessels anomalies. So, it is indispensable as part of adequate preoperative assessment algorithm in cases of complex CHD and can't be replaced by TTE even with the later providing accurate assessment of intra-cardiac anomalies.

Multiscale cardiac imaging spanning the whole heart and its internal cellular architecture in a small animal model

Cardiac pumping depends on the morphological structure of the heart, but also on its subcellular (ultrastructural) architecture, which enables cardiac contraction. In cases of congenital heart defects, localized ultrastructural disruptions that increase the risk of heart failure are only starting to be discovered. This is in part due to a lack of technologies that can image the three-dimensional (3D) heart structure, to assess malformations; and its ultrastructure, to assess organelle disruptions. We present here a multiscale, correlative imaging procedure that achieves high-resolution images of the whole heart, using 3D micro-computed tomography (micro-CT); and its ultrastructure, using 3D scanning electron microscopy (SEM). In a small animal model (chicken embryo), we achieved uniform fixation and staining of the whole heart, without losing ultrastructural preservation on the same sample, enabling correlative multiscale imaging. Our approach enables multiscale studies in models of congenital heart disease and beyond.

ACC/AHA/ASE/HRS/ISACHD/SCAI/SCCT/SCMR/SOPE 2020 Appropriate Use Criteria for Multimodality Imaging During the Follow-Up Care of Patients With Congenital Heart Disease: A Report of the American College of Cardiology Solution Set Oversight Committee and Appropriate Use Criteria Task Force, American Heart Association, American Society of Echocardiography, Heart Rhythm Society, International Society for Adult Congenital Heart Disease, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and Society of Pediatric Echocardiography

The American College of Cardiology (ACC) collaborated with the American Heart Association, American Society of Echocardiography, Heart Rhythm Society, International Society for Adult Congenital Heart Disease, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and the Society of Pediatric Echocardiography to develop Appropriate Use Criteria (AUC) for multimodality imaging during the follow-up care of patients with congenital heart disease (CHD). This is the first AUC to address cardiac imaging in adult and pediatric patients with established CHD. A number of common patient scenarios (also termed "indications") and associated assumptions and definitions were developed using guidelines, clinical trial data, and expert opinion in the field of CHD.1 The indications relate primarily to evaluation before and after cardiac surgery or catheter-based intervention, and they address routine surveillance as well as evaluation of new-onset signs or symptoms. The writing group developed 324 clinical indications, which they separated into 19 tables according to the type of cardiac lesion. Noninvasive cardiac imaging modalities that could potentially be used for these indications were incorporated into the tables, resulting in a total of 1,035 unique scenarios. These scenarios were presented to a separate, independent panel for rating, with each being scored on a scale of 1 to 9, with 1 to 3 categorized as "Rarely Appropriate," 4 to 6 as "May Be Appropriate," and 7 to 9 as "Appropriate." Forty-four percent of the scenarios were rated as Appropriate, 39% as May Be Appropriate, and 17% as Rarely Appropriate. This AUC document will provide guidance to clinicians in the care of patients with established CHD by identifying the reasonable imaging modality options available for evaluation and surveillance of such patients. It will also serve as an educational and quality improvement tool to identify patterns of care and reduce the number of Rarely Appropriate tests in clinical practice.

Imaging of Fontan-associated liver disease

The Fontan operation has dramatically altered the natural history of functionally single ventricle congenital heart disease. Patients who have undergone the Fontan operation are living longer and, thus, noncardiac morbidity resulting from the Fontan operation is increasingly being recognized. Fontan-associated liver disease (FALD), one of the chief morbidities following the Fontan operation, is believed to be a multifactorial process that manifests as hepatic congestion and fibrosis, portal hypertension, and development of focal liver lesions, including malignant tumors. This article reviews the imaging findings of FALD in the pediatric and young adult population, reviews the literature related to the imaging of FALD and discusses possible screening algorithms for this population. The need for further research to better understand the causes of FALD, to establish if early liver stiffness measurements (or their change over time) predict long-term outcomes and complications, and to define optimal liver screening procedures is highlighted.

Factors Influencing Temporal Trends in Pediatric Inpatient Imaging Utilization

BACKGROUND

Concern exists over exponential growth in cardiac imaging in adults, but there is paucity of such data for cardiac imaging trends in pediatric patients. The aims of this study were to determine temporal trends in the use of noninvasive cardiac imaging and compare these with trends in the use of noncardiac imaging and to identify factors influencing those trends using the Pediatric Health Information Service database.

METHODS

Pediatric inpatient encounter data from January 2004 to December 2017 at 35 pediatric hospitals were extracted from the Pediatric Health Information Service database. Temporal imaging utilization trends in cardiac and noncardiac ultrasound or echocardiography, magnetic resonance imaging (MRI), and computed tomography (CT) were assessed using linear mixed-effects models. Models were adjusted for case-mix index, complex chronic conditions, patient age, length of stay, payer source, and cardiac surgical volume.

RESULTS

A total of 5,869,335 encounters over 14 years were analyzed (median encounters per center per year, 11,411; median patient age, 4 years; median length of stay, 3 days). From 2004 to 2017, the rates of pediatric inpatient cardiac and noncardiac ultrasound and MRI increased, whereas the rate of noncardiac CT decreased. Cardiac CT use increased beginning in 2014 (+0.264 cardiac CT encounters per 1,000 encounters per year), surpassing the rate of rise of cardiac MRI. Case-mix index, cardiac surgical volume, and payer source affected the largest number of imaging trends.

CONCLUSIONS

Among pediatric inpatients, utilization of cardiac and noncardiac ultrasound and MRI has steadily increased. Noncardiac CT use declined and cardiac CT use increased after 2014. Factors influencing imaging trends include case-mix index, cardiac surgical volume, and payer source. This study lays a foundation for investigations of imaging-related resource utilization and outcomes among pediatric inpatients.

Accuracy and sensitivity of three-dimensional echocardiography to detect changes in right ventricular volumes: comparison study with cardiac magnetic resonance

We aimed to investigate the ability of three-dimensional transthoracic echocardiography (3DE) to detect changes in RV volumes compared to cardiac magnetic resonance (CMR). Eighty-five subjects including 45 with no known cardiac disease and 40 patients with a variety of cardiac diseases were included. Two- and three-dimensional echocardiography as well as CMR of the RV was performed before and after infusion of on average two litres of saline. Examinations were analysed with estimation of RV dimensions, volumes and ejection fraction (RVEF). Intra- and inter-examiner variability was evaluated in 25 patients randomly selected from the cohort. Three-dimensional echocardiography underestimated volumes and RVEF compared to CMR with mean differences and 95% limits of agreement of 110.3 ± 59 mL for RV end-diastolic volume (RVEDV), 43.3 ± 32 mL for RV end-systolic volume (RVESV) and 3.5 ± 10.7% for RVEF. CMR was more reproducible than 3DE, with intra-observer coefficient of variation (CV) of 4% vs. 14.2% for RVEDV, 9.7% vs. 16.7% for RVESV and 6.3% vs. 8.6% for RVEF. The RVEDV, RVESV and RV stroke volume (RVSV) by CMR significantly increased after saline infusion by 15.3 ± 16.2 mL, 3.5 ± 14.2 mL and 11.8 ± 12.6 mL, respectively, as well as RVEF by 1.5 ± 4.6% (p < 0.05). However, 3DE was not able to detect any of these changes in RV volumes (p ≥ 0.05). Compared to CMR imaging of the RV, three-dimensional echocardiography appears unable and unreliable in detecting RV volume changes of less than 15%, highlighting the need for cautious utility of 3DE in these circumstances.

[Retrospective Study of Image Quality in Pediatric Cardiac Cine MRI]

In pediatric cardiac cine magnetic resonance imaging (MRI), it must overcome several challenges including the patient's size and higher heart rate. The aim of this study was to retrospectively evaluate imaging optimization. Cardiac cine MRI data from 24 patients was analyzed (age range: 3 months-10 years, average age: 5 years, male/female: 11/13, R-R interval: 450±4 to 819±7 ms). About 11 cases out of 24 have good image quality. For small variations in the R-R interval and higher temporal resolution improved image quality with significant difference (P<0.05, Mann-Whitney U-test). In this study, values of temporal resolution <30 ms yielded good image quality for heart rates over 100 bpm. On the other hands, the factors dependent on the patient like heart rate and ejection fraction have no significant difference. The segmentation of data acquisition is more significant than recording small fields of view or thin slices for infantile and pediatric cardiac cine MRI. Similar to adult cases, variations in heart rate affect the image quality; however, we demonstrated that using segmentation of data acquisition results in improved image quality.

Diagnosis and treatment of adults with congenital heart disease

Approximately 50 million adults worldwide have known congenital heart disease (CHD). Among the most common types of CHD defects in adults are atrial septal defects and ventricular septal defects followed by complex congenital heart lesions such as tetralogy of Fallot. Adults with CHDs are more likely to have hypertension, cerebral vascular disease, diabetes and chronic kidney disease than age-matched controls without CHD. Moreover, by the age of 50, adults with CHD are at a greater than 10% risk of experiencing cardiac dysrhythmias and approximately 4% experience sudden death. Consequently, adults with CHD require healthcare that is two- to four-times greater than adults without CHD. This paper discusses the diagnosis and treatment of adults with atrial septal defects, ventricular septal defects and tetralogy of Fallot.

Localization of common carotid artery transverse section in B-mode ultrasound images using faster RCNN: a deep learning approach

Cardiologists can acquire important information related to patients' cardiac health using carotid artery stiffness, its lumen diameter (LD), and its carotid intima-media thickness (cIMT). The sonographers primarily concern about the location of the artery in B-mode ultrasound images. Localization using manual methods is tedious and time-consuming and also may lead to some errors. On the other hand, automated approaches are more objective and can provide the localization of the artery at near real time. Above arterial parameters may be determined after localization of the artery in real time.A novel method of localization of common carotid artery (CCA) transverse section is presented in this work. The method is known as fast region convolutional neural network (FRCNN)-based localization method and is designed using a stack of three layers viz. convolutional layers, fully connected layers, and pooling layers. These organized layers constitute a region proposal network (RPN) and an object class detection network (OCDN). We obtain an outcome as a bounding box along with a score of prediction around the cross-section of the CCA.B-mode ultrasound image database of CCA is split into training and testing set, to accomplish this, three partition methods K = 2, 5, and 10 are used in our work. The training is extended for 30, 200, and 2000 epochs in order to achieve fine-tuned features from the convolutional neural network. After 2000 epochs, we obtain 95% validation accuracy; however, mean of the accuracies up to 2000 epochs is 89.36% for K = 10 partitions protocol (training 90%, testing 10%). Generated CNN model is tested on a different dataset of 433 images and the acquired accuracy is 87.99%. Thus, the proposed method including an advanced deep learning technique demonstrates promising localization for carotid artery transverse section. Graphical abstract.

The Limited Benefit of Follow-Up Echocardiograms After Repair of Tetralogy of Fallot

Tetralogy of Fallot (ToF) is the most common cyanotic congenital heart disease, making up 10% of all congenital heart defects. Annual follow-up echocardiograms are recommended in patients with repaired ToF, but evidence-based guidelines do not exist. We hypothesized that most echocardiograms performed in asymptomatic patients with repaired ToF and no physical exam change do not result in an actionable change (AC) in management. We retrospectively reviewed records of all patients with ToF and prior complete repair at our institution between January 2000 and September 2015. Changes in echocardiograms resulting in hospital admission, medication addition/change, cardiac catheterization, or surgical procedure were identified via chart review. These changes were referred to as an AC. A total of 1135 echocardiograms were reviewed from 233 patients (160 with initial complete repair, 70 with prior shunt, and 3 with other initial surgery). The median number of echocardiograms per patient was 5. Of the 1135 echocardiograms, 15 (1.3%) were associated with AC. Of the 15 patients with AC echocardiograms, 9 underwent a shunt prior to complete repair (9/70, 12.9%) and 6 had undergone an initial complete repair (6/160, 3.8%). The median age at AC was 6.3 years (IQR 4.4, 6.8) in the shunt group and 0.90 years (IQR 0.87, 1.1) in the initial complete repair group. In asymptomatic patients with repaired ToF and no physical exam change, echocardiograms rarely lead to a change in clinical management. In conclusion, the likelihood and timing of AC echocardiograms and reinterventions vary based on the type of initial surgery.

Artificial intelligence in pediatric and adult congenital cardiac MRI: an unmet clinical need

Cardiac MRI (CMR) allows non-invasive, non-ionizing assessment of cardiac function and anatomy in patients with congenital heart disease (CHD). The utility of CMR as a non-invasive imaging tool for evaluation of CHD have been growing exponentially over the past decade. The algorithms based on artificial intelligence (AI), and in particular, deep learning, have rapidly become a methodology of choice for analyzing CMR. A wide range of applications for AI have been developed to tackle challenges in various aspects of CMR, and significant advances have also been made from image acquisition to image analysis and diagnosis. We include an overview of AI definitions, different architectures, and details on well-known methods. This paper reviews the major deep learning concepts used for analyses of patients with CHD. In the end, we have summarized a list of open challenges and concerns to be considered for future studies.

mDixon ECG-gated 3-dimensional cardiovascular magnetic resonance angiography in patients with congenital cardiovascular disease

BACKGROUND

Cardiovascular magnetic resonance (CMR) angiography (CMRA) is an important non-invasive imaging tool for congenital heart disease (CHD) and aortopathy patients. The conventional 3D balanced steady-state free precession (bSSFP) sequence is often confounded by imaging artifacts. We sought to compare the respiratory navigated and electrocardiogram (ECG) gated modified Dixon (mDixon) CMRA sequence to conventional non-gated dynamic multi-phase contrast enhanced CMRA (CE-CMRA) and bSSFP across a variety of diagnoses.

METHODS

We included 24 patients with CHD or aortopathy with CMR performed between September 2017 to December 2017. Each patient had undergone CE-CMRA, followed by a bSSFP and mDixon angiogram. Patients with CMR-incompatible implants or contraindications to contrast were excluded. The studies were rated according to image quality at a scale from 1 (poor) to 4 (excellent) based on diagnostic adequacy, artifact burden, vascular border delineation, myocardium-blood pool contrast, and visualization of pulmonary and systemic veins and coronaries. Contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and quantitative vascular measurements were compared between the two gated sequences. Bland-Altman plots were generated to compare paired measures.

RESULTS

All scans were diagnostically adequate. Mean (SD) quality scores were 3.4 (0.7) for the mDixon, 3.2 (0.5) for the bSSFP and 3.4 (0.5) for the CE-CMRA. Qualitatively, the intracardiac anatomy and myocardium-blood pool definition were better in the bSSFP; however, mDixon images showed enhanced vessel wall sharpness with less blurring surrounding the anatomical borders distally. Coronary origins were identified in all cases. Pulmonary veins were visualized in 92% of mDixon sequences, 75% of bSSFP and 96% of CE-CMRA. Similarly, neck veins were identified in 92, 83 and 96% respectively. Artifacts prevented vascular measurement in 6/192 (3%) and 4/192 (2%) of total vascular measurements for the mDixon and bSSFP, respectively. However, the size of signal void and field distortion were significantly worse in the latter, particularly for flow and metal induced artifacts.

CONCLUSION

In patients with congenital heart disease, ECG gated mDixon angiography yields high fidelity vascular images including better delineation of head and neck vasculature and pulmonary veins and fewer artifacts than the comparable bSSFP sequence. It should be considered as the preferred strategy for successful CHD imaging in patients with valve stenosis, vascular stents, or metallic implants.

A Primer on Multimodal Imaging and Cardiology-Radiology Congenital Heart Interface

Pediatric cardiology imaging laboratories in the present day have several modalities for imaging of congenital and acquired cardiovascular disease. These modalities include echocardiography, cardiovascular magnetic resonance imaging, cardiac computed tomography and nuclear imaging. The utility and limitations of multimodal imaging is described herein along with a framework for establishing a cardiology-radiology interface.

Validation of aortic valve 4D flow analysis and myocardial deformation by cardiovascular magnetic resonance in patients after the arterial switch operation

BACKGROUND

Aortic regurgitation (AR) and subclinical left ventricular (LV) dysfunction expressed by myocardial deformation imaging are common in patients with transposition of the great arteries after the arterial switch operation (ASO). Echocardiographic evaluation is often hampered by reduced acoustic window settings. Cardiovascular magnetic resonance (CMR) imaging provides a robust alternative as it allows for comprehensive assessment of degree of AR and LV function. The purpose of this study is to validate CMR based 4-dimensional flow quantification (4D flow) for degree of AR and feature tracking strain measurements for LV deformation assessment in ASO patients.

METHODS

A total of 81 ASO patients (median 20.6 years, IQR 13.5-28.4) underwent CMR for 4D and 2D flow analysis. CMR global longitudinal strain (GLS) feature tracking was compared to echocardiographic (echo) speckle tracking. Agreements between and within tests were expressed as intra-class correlation coefficients (ICC).

RESULTS

Eleven ASO patients (13.6%) showed AR > 5% by 4D flow, with good correlation to 2D flow assessment (ICC = 0.85). 4D flow stroke volume of the aortic valve demonstrated good agreement to 2D stroke volume over the mitral valve (internal validation, ICC = 0.85) and multi-slice planimetric LV stroke volume (external validation, ICC = 0.95). 2D flow stroke volume showed slightly less, though still good agreement with 4D flow (ICC = 0.78) and planimetric LV stroke volume (ICC = 0.87). GLS by CMR was normal (- 18.8 ± 4.4%) and demonstrated good agreement with GLS and segmental analysis by echocardiographic speckle tracking (GLS = - 17.3 ± 3.1%, ICC of 0.80).

CONCLUSIONS

Aortic 4D flow and CMR feature tracking GLS analysis demonstrate good to excellent agreement with 2D flow assessment and echocardiographic speckle tracking, respectively, and can therefore reliably be used for an integrated and comprehensive CMR analysis of aortic valve competence and LV deformation analysis in ASO patients.

Pediatric Transthoracic Cardiac Vector Flow Imaging - A Preliminary Pictorial Study

Purpose Conventional pediatric echocardiography is crucial for diagnosing congenital heart disease (CHD), but the technique is impaired by angle dependency. Vector flow imaging (VFI) is an angle-independent noninvasive ultrasound alternative for blood flow assessment and can assess complex flow patterns not visible on conventional Doppler ultrasound.

Materials and Methods 12 healthy newborns and 3 infants with CHD were examined with transthoracic cardiac VFI using a conventional ultrasound scanner and a linear array.

Results VFI examinations revealed common cardiac flow patterns among the healthy newborns, and flow changes among the infants with CHD not previously reported with conventional echocardiography.

Conclusion For assessment of cardiac flow in the normal and diseased pediatric heart, VFI may provide additional information compared to conventional echocardiography and become a useful diagnostic tool.

Evaluation of a Portable Doppler Ultrasound Gating Device for Fetal Cardiac MR Imaging: Initial Results at 1.5T and 3T

Purpose:

Fetal cardiac MRI has the potential to play an important role in the assessment of fetal cardiac pathologies, but it is up to now not feasible due to a missing gating method. The purpose of this work was the evaluation of Doppler ultrasound (DUS) for external fetal cardiac gating with regard to compatibility, functionality, and reliability. Preliminary results were assessed performing fetal cardiac MRI.

Methods:

An MRI conditional DUS device was developed to obtain a gating signal from the fetal heart. The MRI compatibility was evaluated at 1.5T and 3T using B₁ field maps and gradient echo images. The quality and sensitivity of the DUS device to detect the fetal heart motion for cardiac gating were evaluated outside the MRI room in 15 fetuses. A dynamic fetal cardiac phantom was employed to evaluate distortions of the DUS device and gating signal due to electromagnetic interferences at 1.5T and 3T. In the first in vivo experience, dynamic fetal cardiac images were acquired in four-chamber view at 1.5T and 3T in two fetuses.

Results:

The maximum change in the B₁ field and signal intensity with and without the DUS device was <6.5% for 1.5T and 3T. The sensitivity of the DUS device to detect the fetal heartbeat was 99.1%. Validation of the DUS device using the fetal cardiac phantom revealed no electromagnetic interferences at 1.5T or 3T and a high correlation to the simulated heart frequencies. Fetal cardiac cine images were successfully applied and showed good image quality.

Conclusion:

An MR conditional DUS gating device was developed and evaluated revealing safety, compatibility, and reliability for different field strengths. In a preliminary experience, the DUS device was successfully applied for in vivo fetal cardiac imaging at 1.5T and 3T.

Radiation dose management for pediatric cardiac computed tomography: a report from the Image Gently 'Have-A-Heart' campaign

Children with congenital or acquired heart disease can be exposed to relatively high lifetime cumulative doses of ionizing radiation from necessary medical imaging procedures including radiography, fluoroscopic procedures including diagnostic and interventional cardiac catheterizations, electrophysiology examinations, cardiac computed tomography (CT) studies, and nuclear cardiology examinations. Despite the clinical necessity of these imaging studies, the related ionizing radiation exposure could pose an increased lifetime attributable cancer risk. The Image Gently "Have-A-Heart" campaign is promoting the appropriate use of medical imaging studies in children with congenital or acquired heart disease while minimizing radiation exposure. The focus of this manuscript is to provide a comprehensive review of radiation dose management and CT performance in children with congenital or acquired heart disease.