Utilizing Artificial Intelligence-Based Deformable Registration for Global and Layer-Specific Cardiac MRI Strain Analysis in Healthy Children and Young Adults

RATIONALE AND OBJECTIVES

The absence of published reference values for multilayer-specific strain measurement using cardiac magnetic resonance (CMR) in young healthy individuals limits its use. This study aimed to establish normal global and layer-specific strain values in healthy children and young adults using a deformable registration algorithm (DRA).

MATERIALS AND METHODS

A retrospective study included 131 healthy children and young adults (62 males and 69 females) with a mean age of 16.6 ± 3.9 years. CMR examinations were conducted using 1.5T scanners, and strain analysis was performed using TrufiStrain research prototype software (Siemens Healthineers, Erlangen, Germany). Global and layer-specific strain parameters were extracted from balanced Steady-state free precession cine images. Statistical analyses were conducted to evaluate the impact of demographic variables on strain measurements.

RESULTS

The peak global longitudinal strain (LS) was -16.0 ± 3.0%, peak global radial strain (RS) was 29.9 ± 6.3%, and peak global circumferential strain (CS) was -17.0 ± 1.8%. Global LS differed significantly between males and females. Transmural strain analysis showed a consistent pattern of decreasing LS and CS from endocardium to epicardium, while radial strain increased. Basal-to-apical strain distribution exhibited decreasing LS and increasing CS in both global and layer-specific analysis.

CONCLUSION

This study uses DRA to provide reference values for global and layer-specific strain in healthy children and young adults. The study highlights the impact of sex and age on LS and body mass index on RS. These insights are vital for future cardiac assessments in children, particularly for early detection of heart diseases.

"From Vision to Reality: Virtual Reality's Impact on Baffle Planning in Congenital Heart Disease"

This study aims to evaluate the feasibility and utility of virtual reality (VR) for baffle planning in congenital heart disease (CHD), specifically by creating patient-specific 3D heart models and assessing a user-friendly VR interface. Patient-specific 3D heart models were created using high-resolution imaging data and a VR interface was developed for baffle planning. The process of model creation and the VR interface were assessed for their feasibility, usability, and clinical relevance. Collaborative and interactive planning within the VR space were also explored. The study findings demonstrate the feasibility and usefulness of VR in baffle planning for CHD. Patient-specific 3D heart models generated from imaging data provided valuable insights into complex spatial relationships. The developed VR interface allowed clinicians to interact with the models, simulate different baffle configurations, and assess their impact on blood flow. The VR space's collaborative and interactive planning enhanced the baffle planning process. This study highlights the potential of VR as a valuable tool in baffle planning for CHD. The findings demonstrate the feasibility of using patient-specific 3D heart models and a user-friendly VR interface to enhance surgical planning and patient outcomes. Further research and development in this field are warranted to harness the full benefits of VR technology in CHD surgical management.

Common Arterial Trunk Coexisting With Double-Barreled Aorta

This case describes the first example of a double-barreled aorta in the setting of a common arterial trunk. Our use of annotated and segmented 3-dimensional models greatly enhanced our ability to elucidate the complex anatomy. (Level of Difficulty: Advanced.).

Palliative Procedures for Congenital Heart Disease: Imaging Findings and Complications

Palliative procedures are performed for congenital heart diseases that are not amenable for definitive surgical procedures or as a component of hybrid procedures along with transcatheter interventions. Multimodality imaging plays an important role in the follow-up of these palliative procedures, mainly for the timely detection of complications and for planning any subsequent palliative or definitive procedure. Echocardiography is the first-line imaging modality, with CT and MRI used as complementary techniques in indeterminate cases. MRI provides anatomic, functional, flow, and tissue characterization information. CT is performed for the evaluation of vascular anatomy and when MRI cannot be performed due to contraindications, challenges, or artifacts. The modified Blalock-Taussig shunt procedure is the most common systemic-pulmonary artery (PA) shunt procedure, with thrombus being the most serious complication. Other complications of systemic-PA shunts include shunt stenosis, infection, pulmonary overcirculation, and cardiac failure. The Glenn shunt procedure is the second stage of palliation in single ventricle physiology, with thrombus, stenosis, superior vena cava syndrome, and infection being the common complications. The Fontan shunt procedure is the third stage of palliation in single ventricle physiology. Complications can be cardiovascular (heart failure, valve regurgitation, thromboembolism, shunt stenosis, arteriovenous malformation), venolymphatic (collaterals, protein-losing enteropathy, plastic bronchitis), or hepatic (congestion, cirrhosis, portal hypertension). PA banding is used to decrease pulmonary flow or to train the systemic ventricle. Complications include stenosis, thrombus, erosion, pseudoaneurysm, and subaortic obstruction. Atrial septostomy and atrial switch procedures are performed for increasing intracardiac mixing. Complications of atrial septostomy can be mechanical, traumatic, embolic, or electrical. Complications of the atrial switch procedure include baffle stenosis, baffle leak, and systemic ventricle failure. The authors review the role of multimodality imaging in the evaluation of these palliative procedures. ^© RSNA, 2023 See the invited commentary by Bardo and Popescu in this issue. Quiz questions for this article are available through the Online Learning Center.

Pouch Transfer for Single Coronary Artery With Nodal Artery Variant in Arterial Switch Operation

The arterial switch operation with single coronary artery variance is an independent risk factor for increased operative mortality. There are reports of technical modifications, such as the double-barreled sinus pouch configuration, to improve geometric reimplantation of the single coronary into the neoaortic sinus. We describe the novel application of this technique for transferring a single coronary artery with a separate nodal artery emanating from the opposite sinus during an arterial switch operation.

Two-staged surgical repair of Berry syndrome type 2B

Berry syndrome is a rare congenital heart disease that requires complete corrective surgery. In certain extreme cases, such as ours, a two-stage as opposed to single-stage repair is a possibility. In doing so, we also used annotated and segmented three-dimensional models for the first time in Berry syndrome, adding to growing evidence that such models enhance the understanding of complex anatomy for surgical planning.

Imaging of the Rare Association of Truncus Arteriosus in a Neonate with the Ductal Origin of the Left Subclavian Artery Using Multidetector CT Angiography and 3D Rendering

We present the unreported case of a rare association of truncus arteriosus with the ductal origin of the left subclavian artery. Understanding and preoperative identification of these aortic variations are essential to guide optimal surgical management. In this study, the role of advanced visualization 3D modeling techniques in imaging these complex anomalies is discussed.

mRNA Coronavirus Disease 2019 Vaccine-Associated Myopericarditis in Adolescents: A Survey Study

In this survey study of institutions across the US, marked variability in evaluation, treatment, and follow-up of adolescents 12 through 18 years of age with mRNA coronavirus disease 2019 (COVID-19) vaccine-associated myopericarditis was noted. Only one adolescent with life-threatening complications was reported, with no deaths at any of the participating institutions.

Infantile Scimitar Syndrome With Contralateral Pulmonary Vein Stenosis and Refractory Pulmonary Hypertension

Infantile scimitar syndrome is associated with pulmonary hypertension which can be difficult to manage. We present a three-month-old infant with scimitar syndrome, who eventually developed refractory pulmonary hypertension, posing a significant management challenge. Further workup demonstrated contralateral pulmonary vein stenosis, which is rarely described in scimitar syndrome. Our index case highlights the importance of follow-up cardiac catheterizations in these patients with severe pulmonary hypertension.

Accuracy of Cardiac Magnetic Resonance Imaging Diagnosis of Pediatric Cardiac Masses: A Multicenter Study

OBJECTIVES

The goals of this study were to: 1) evaluate the cardiac magnetic resonance (CMR) characteristics of pediatric cardiac masses from a large international cohort; 2) test the accuracy of previously developed CMR-based diagnostic criteria; and 3) expand diagnostic criteria using new information.

BACKGROUND

After diagnosis of a cardiac mass, clinicians must weigh the benefits and risks of ascertaining a tissue diagnosis. Limited data are available on the accuracy of previously developed noninvasive pediatric CMR-based diagnostic criteria.

METHODS

CMR studies (children 0-18 years of age) with confirmatory histological and/or genetic diagnosis were analyzed by 2 reviewers, without knowledge of prior diagnosis. Diagnostic accuracy was graded as: 1) single correct diagnosis; 2) correct diagnosis among a differential; or 3) incorrect diagnosis.

RESULTS

Of 213 cases, 174 (82%) had diagnoses that were represented in the previously published diagnostic criteria. In 70% of 174 cases, both reviewers achieved a single correct diagnosis (94% of fibromas, 71% of rhabdomyomas, and 50% of myxomas). When ≤2 differential diagnoses were included, both reviewers reached a correct diagnosis in 86% of cases. Of 29 malignant tumors, both reviewers indicated malignancy as a single diagnosis in 52% of cases. Including ≤2 differential diagnoses, both reviewers indicated malignancy in 83% of cases. Of 6 CMR sequences examined, acquisition of first-pass perfusion and late gadolinium enhancement were independently associated with a higher likelihood of a single correct diagnosis.

CONCLUSIONS

CMR of cardiac masses in children leads to an accurate diagnosis in most cases. A comprehensive imaging protocol is associated with higher diagnostic accuracy.

Double-Outlet Right Ventricle, Pulmonary Atresia, and Discontinuous Branch Pulmonary Arteries Supplied by Bilateral Ducti

We present a rare case of double-outlet right ventricle with pulmonary atresia and discontinuous branch pulmonary arteries supplied by bilateral ducti from a right aortic arch. To our knowledge, this is only the second documented case of double-outlet right ventricle with bilateral ducti. (Level of Difficulty: Advanced.)

Assessment of superior vena cava flow and cardiac output in different patterns of patent ductus arteriosus shunt

BACKGROUND

Despite the widespread use of superior vena cava (SVC) flow as a marker of systemic blood flow from the upper body, no previous studies have systematically evaluated the correlation between SVC flow and other echocardiography measures of systemic blood flow in the context of different patterns of patent ductus arteriosus (PDA) shunt direction METHODS: A retrospective cohort study of preterm infants (< 30 weeks, < 21 days of life) who underwent comprehensive targeted neonatal echocardiography (TnECHO) was performed. Patients were categorized as follows: (i) Hemodynamically significant left-to-right shunt; (ii): Bidirectional shunt; (iii) No PDA or insignificant shunt. SVC flow, as measured by two distinct methods, was compared to left and right ventricular outputs (LVO and RVO). Intra- and inter-observer reliability testing was performed RESULTS: In total, 45 patients were included (15 in each group) with a median [IQR] weight of 720 [539, 917] grams at the time of assessment. SVC dimensions and flow measurements were not different between the groups, although patients with left-to-right shunt had higher LVO/RVO ratio. SVC flow, as estimated using the modified method, had a strong correlation with LVO (r = .63, p = 0.012) and RVO (r = .635, p = 0.011) in patients with no PDA. Inter- and intra-observer reliability were both stronger for LVO and RVO when compared to SVC flow measurements CONCLUSION: SVC flow was comparable across all three groups irrespective of higher LVO and LVO/RVO ratio in patients with left-to-right shunts. This may reflect poor measurement reliability or compensation for left-to-right ductal shunt by increased LVO to maintain systemic perfusion.

Anomalous Left Anterior Descending Coronary Artery With Retroaortic Left Circumflex Artery: A Novel Coronary Pattern

A novel coronary anatomy in the form of anomalous left anterior descending coronary artery from pulmonary artery with a retroaortic left circumflex arising from the right coronary artery is presented. This unreported anatomy was discovered in a 7-month-old girl with failure to thrive. (Level of Difficulty: Intermediate.).

Patient-Specific Patch for an Intra-Atrial Rerouting Procedure Developed Through Surgical Simulation

BACKGROUND

In pediatric cardiac surgery, an application of three-dimensional (3D) modeling to develop custom-made prostheses is limited, and currently surgeons use their intraoperative visual estimation to develop 3D complex structures from 2D patch materials. Contemporary 3D designers are developing complex surfaces using surface modeling in other industries, which can be applied to pediatric cardiac surgery. However, its free-form nature may lead to intradesigner variability.

METHODS

A patient with a body weight of 4 kg with partial anomalous pulmonary venous connection and preoperative computed tomography data was selected, and a patient-specific 3D heart model was obtained. Through collaboration with a pediatric cardiologist and a pediatric cardiac surgeon, a 3D designer developed two patient-specific 3D patches for an intra-atrial rerouting procedure (IAR) for the patient using different methods of surface modeling. The shape and size of two flattened patches were analyzed using a geometric morphometrics (GM) approach. Computational fluid dynamics (CFD) analysis was also performed to calculate pressure drop across streamlines and flow energy loss in the right atrium for both patches.

RESULTS

The GM analysis showed that the size and shape of the two patches around the systemic vein orifice, crucial to prevent systemic venous obstruction, were almost equivalent. However, the CFD analysis showed that the pressure drop and flow energy loss were almost twice for one patch compared with the other.

CONCLUSIONS

Our platform of developing a patient-specific 3D patch for an IAR procedure using surface modeling seemed promising, although intradesigner patch variability was not neglectable in our small-sized patient.

Multimodality Imaging of Transposition of the Great Arteries

Transposition of the great arteries (TGA) is a congenital conotruncal abnormality characterized by discordant connections between the ventricles and great arteries, with the aorta originating from the right ventricle (RV), and the pulmonary artery (PA) originating from the left ventricle (LV). The two main types of TGA are complete transposition or dextro-transposition of the great arteries (D-TGA), commonly referred to as d-loop, and congenitally corrected transposition (CCTGA), commonly referred to as l-loop or L-TGA. In D-TGA, the connections between the ventricles and atria are concordant, whereas in CCTGA they are discordant, with the left atrium connected to the RV, and the right atrium connected to the LV. D-TGA manifests during the neonatal period and can be surgically managed by atrial switch operation (AtrSO), arterial switch operation (ASO), Rastelli procedure, or Nikaidoh procedure. Arrhythmia, systemic ventricular dysfunction, baffle stenosis, and baffle leak are the common complications of AtrSO, whereas supravalvular pulmonary or branch PA stenosis, neoaortic dilatation, and coronary artery narrowing are the common complications of ASO. CCTGA may manifest late in life, even in adulthood. Surgeries for associated lesions such as tricuspid regurgitation, subpulmonic stenosis, and ventricular septal defect may be performed. A double-switch operation that includes both the atrial and arterial switch operations constitutes anatomic correction for CCTGA. Imaging plays an important role in the evaluation of TGA, both before and after surgery, for helping define the anatomy, quantify hemodynamics, and evaluate complications. Transthoracic echocardiography is the first-line imaging modality for presurgical planning in children with TGA. MRI provides comprehensive morphologic and functional information, particularly in adults after surgery. CT is performed when MRI is contraindicated or expected to generate artifacts. The authors review the imaging appearances of TGA, with a focus on pre- and postsurgical imaging. Online supplemental material is available for this article. ^©RSNA, 2021.

Anatomic Concordance of Neonatologist-Performed Echocardiography as Part of Hemodynamics Consultation and Pediatric Cardiology

BACKGROUND

Targeted neonatal echocardiography (TnECHO) performed by neonatologists as part of a hemodynamics consultation is increasingly being used in neonatal intensive care units. To minimize delays in obtaining physiologic data, first echocardiograms may be obtained by the neonatal hemodynamics team and reviewed afterward by a pediatric cardiologist. This practice has not been systematically evaluated. The aim of this study was to compare concordance between anatomic findings on TnECHO and pediatric cardiology reports.

METHODS

This was a retrospective evaluation of 339 infants at low risk for congenital heart disease (CHD) admitted to two large referral centers with established neonatal hemodynamics programs who underwent comprehensive TnECHO as their first postnatal echocardiographic examinations. The protocol included comprehensive imaging of intracardiac anatomy, outflow tract concordance and integrity, aortic arch anatomy, pulmonary vein location and flow, and transitional shunts. The hemodynamics consultation note was compared with the cardiology report to determine anatomic concordance or major or minor discrepancies in all first studies.

RESULTS

Anatomic concordance occurred in 97.9% (κ = 0.862; 95% CI, 0.762-0.962; P < .001). There were seven minor discrepancies (small muscular ventricular septal defects and coronary fistulas). The index population included 23 infants (6.7%) with CHD, of whom only one (0.3%) had a ductal-dependent lesion (coarctation of the aorta) which was correctly identified by both teams.

CONCLUSIONS

The rate of major CHD in patients considered eligible for hemodynamics consultation was low, and there was high diagnostic concordance between trained neonatal hemodynamics specialists and pediatric cardiology. First echocardiograms obtained by subspecialty neonatologists may provide imaging of sufficient quality to evaluate a critically unwell neonate with low suspicion for critical CHD lesions. These results should not be extrapolated to infants in whom CHD is suspected. This study highlights the importance of formalized, rigorous, and standardized training for neonatologists with hemodynamics expertise who perform timely assessments using TnECHO.

Evaluation of Transcatheter Pulmonary Valve Endocarditis by Dual-Energy Computed Tomography

Transcatheter pulmonary valve implantation (TPVI) is now an established alternative to surgery in patients with congenital heart disease and dysfunctional right ventricular outflow tract (RVOT) conduit. However, there is recognition of a higher incidence of infective endocarditis in the patients after TPVI. Transthoracic and transesophageal echocardiography is limited in the evaluation of prosthetic pulmonary valve endocarditis secondary to a metallic artifact and degenerative calcified conduit. Additionally, the anterior position of RVOT also limits evaluation by echocardiography. Conventional single-energy CTA can also be sub-optimal in evaluating prosthetic pulmonary valve stent frame due to streak artifacts from the metallic cage and poor contrast to noise ratio if higher kV is used for single-energy CTA to avoid metallic artifacts. Dual-energy CTA can overcome these limitations using reconstructed virtual monoenergetic and iodine-only images for metal artifact reduction and improve intra-stent luminal visualization. Reconstructed iodine perfusion maps may also help differentiate vegetation from a thrombus. In this case report, we discuss the diagnostic utility of dual-energy cardiac CT in the evaluation of endocarditis after TPVI and discuss the imaging protocol.

Insights into Arch Vessel Development in the Bovine Aortic Arch

A bovine arch is the most common aortic arch variant, characterized by a common origin of the innominate artery and the left common carotid artery. Data have shown that children with bovine arch anatomy and coarctation are at a significantly higher risk of recoarctation following coarctation repair. This study aims to explain the higher coarctation rates, assess the branching of the arch vessels, understand their embryologic origins, and delineate the patterns of displacement of the arch vessels in bovine versus normal anatomy. This retrospective study reviewed the medical records of 178 infants ( < 1-year-old) who had a chest CT Angiogram (58) or CT (120) at our institution between 2007 and 2017. Multiplanar reconstruction software was used to obtain the best image plane to display the sinotubular junction, innominate artery, left common carotid artery, and left subclavian artery. We measured the distances between the branches as HV1, HV2, and HV3. All distances were standardized to body surface area and sinotubular junction diameter, which is a novel method. Bovine arches were found in 32.6% of patients. The total arch length of both arch anatomies was similar. HV3 is longer in bovine arches. HV1 + HV2 and HV2 + HV3 are longer in the normal arches than the bovine arches. The left subclavian artery moves proximally, and the innominate artery moves slightly distally to form the bovine arch and decreasing the clamping distance for coarctation repair. Aortic arch distances were similar when standardized to either sinotubular junction diameter and body surface area.

Manifold recovery using kernel low-rank regularization: application to dynamic imaging

We introduce a novel kernel low-rank algorithm to recover free-breathing and ungated dynamic MRI data from highly undersampled measurements. The image frames in the free breathing and ungated dataset are assumed to be points on a bandlimited manifold. We show that the non-linear features of these images satisfy annihilation conditions, which implies that the kernel matrix derived from the dataset is low-rank. We penalize the nuclear norm of the feature matrix to recover the images from highly undersampled measurements. The regularized optimization problem is solved using an iterative reweighted least squares (IRLS) algorithm, which alternates between the update of the Laplacian matrix of the manifold and the recovery of the signals from the noisy measurements. To improve computational efficiency, we use a two step algorithm using navigator measurements. Specifically, the Laplacian matrix is estimated from the navigators using the IRLS scheme, followed by the recovery of the images using a quadratic optimization. We show the relation of this two step algorithm with our recent SToRM approach, thus reconciling SToRM and manifold regularization methods with algorithms that rely on explicit lifting of data to a high dimensional space. The IRLS based estimation of the Laplacian matrix is a systematic and noise-robust alternative to current heuristic strategies based on exponential maps. We also approximate the Laplacian matrix using a few eigen vectors, which results in a fast and memory efficient algorithm. The proposed scheme is demonstrated on several patients with different breathing patterns and cardiac rates.

Bilateral Ductus Arteriosus and Discontinuity of the Pulmonary Branches and Pulmonary Atresia: An Unusual Anatomy Diagnosed by Echocardiography

• Echocardiography can delineate complex congenital anatomy without additional imaging. • A wide range of branch pulmonary artery anatomy is seen in pulmonary atresia. • Bilateral patent ductus arteriosus is an uncommon finding in pediatric cardiology.

Isolated Left Subclavian Artery, Complete Atrioventricular Block, and Tricuspid Atresia in a Neonate

Isolated left subclavian artery is one of the rarer aortic arch anomalies. It has been associated with other congenital heart diseases, typically tetralogy of Fallot, double-outlet right ventricle, and atrial and ventricular septal defects. Its significant clinical implications include a left-to-right shunt from the vertebrobasilar system, which causes pulmonary overcirculation and subclavian steal. We present an unusual case of a premature infant who was diagnosed prenatally with congenital complete atrioventricular block and tricuspid atresia and was found to have an isolated left subclavian artery postnatally. The patient underwent implantation of a permanent single-chamber epicardial pacing system. To our knowledge, this combination of lesions has not been reported-and in our case, it influenced our surgical planning.

Down Syndrome with Complete Atrioventricular Septal Defect, Hypertrophic Cardiomyopathy, and Pulmonary Vein Stenosis

The prevalence of congenital heart disease in infants with Down syndrome is 40%, compared with 0.3% in children who have normal chromosomes. Atrioventricular and ventricular septal defects are often associated with chromosomal aberrations, such as in trisomy 21, whereas hypertrophic cardiomyopathy is chiefly thought to be secondary to specific gene mutations. We found only one reported case of congenital hypertrophic cardiomyopathy and atrioventricular septal defect in an infant with Down syndrome. Here, we report atrioventricular septal defect, hypertrophic cardiomyopathy, and pulmonary vein stenosis in a neonate with Down syndrome-an apparently unique combination. In addition, we discuss the relevant medical literature.

Imaging Cardiovascular Manifestations of Genetic Syndromes

Congenital structural cardiovascular defects are commonly associated and found concurrently with many different types of genetic diseases and syndromes. Understanding these cardiovascular manifestations is essential for diagnosing these genetic syndromes without delay and provides prompt attention and repair of life-threatening defects without complications. Computed tomography and magnetic resonance imaging are increasingly used in the evaluation of cardiovascular abnormalities, and it is imperative for radiologists to be cognizant of the syndromes associated with these abnormalities. In this article, we review the cardiovascular manifestations of the common genetic syndromes and illustrate the role of computed tomography and magnetic resonance imaging in the evaluation of these abnormalities.

Quantification of left ventricular functional parameter values using 3D spiral bSSFP and through-time non-Cartesian GRAPPA

BACKGROUND

The standard clinical acquisition for left ventricular functional parameter analysis with cardiovascular magnetic resonance (CMR) uses a multi-breathhold multi-slice segmented balanced SSFP sequence. Performing multiple long breathholds in quick succession for ventricular coverage in the short-axis orientation can lead to fatigue and is challenging in patients with severe cardiac or respiratory disorders. This study combines the encoding efficiency of a six-fold undersampled 3D stack of spirals balanced SSFP sequence with 3D through-time spiral GRAPPA parallel imaging reconstruction. This 3D spiral method requires only one breathhold to collect the dynamic data.

METHODS

Ten healthy volunteers were recruited for imaging at 3 T. The 3D spiral technique was compared against 2D imaging in terms of systolic left ventricular functional parameter values (Bland-Altman plots), total scan time (Welch's t-test) and qualitative image rating scores (Wilcoxon signed-rank test).

RESULTS

Systolic left ventricular functional values were not significantly different (i.e. 3D-2D) between the methods. The 95% confidence interval for ejection fraction was -0.1 ± 1.6% (mean ± 1.96*SD). The total scan time for the 3D spiral technique was 48 s, which included one breathhold with an average duration of 14 s for the dynamic scan, plus 34 s to collect the calibration data under free-breathing conditions. The 2D method required an average of 5 min 40s for the same coverage of the left ventricle. The difference between 3D and 2D image rating scores was significantly different from zero (Wilcoxon signed-rank test, p < 0.05); however, the scores were at least 3 (i.e. average) or higher for 3D spiral imaging.

CONCLUSION

The 3D through-time spiral GRAPPA method demonstrated equivalent systolic left ventricular functional parameter values, required significantly less total scan time and yielded acceptable image quality with respect to the 2D segmented multi-breathhold standard in this study. Moreover, the 3D spiral technique used just one breathhold for dynamic imaging, which is anticipated to reduce patient fatigue as part of the complete cardiac examination in future studies that include patients.

Computed tomography in the evaluation of vascular rings and slings

Vascular rings are congenital abnormalities of the aortic arch-derived vascular and ligamentous structures, which encircle the trachea and oesophagus to varying degrees, resulting in respiratory or feeding difficulties in children. A sling is an abnormality of the pulmonary arterial system resulting in airway compression. Although several imaging examinations are available for the evaluation of these anomalies, computed tomography (CT) has become the preferred test because of rapid acquisitions, making it feasible to perform the study without sedation or general anaesthesia. Furthermore, CT provides excellent spatial and temporal resolution, a wide field of view, multiplanar reconstruction capabilities and simultaneous evaluation of the airway. In this review, the current role and technique of CT in the evaluation of vascular rings are discussed. A brief discussion of the embryology of the aorta and branch vessels is followed by discussion and illustration of common and some uncommon vascular rings along with critical information required by surgeons. Teaching Points • Computed tomography is valuable in the evaluation of vascular rings.• Due to variable clinical and imaging presentations, diagnosis of vascular rings is often challenging.• Laterality of the arch is critical in surgical management.

Bilateral absence of superior vena cava

The absence of a right superior vena cava (SVC) in situs solitus is very rare, and even then it is usually associated with left SVC. There have been few case reports in the literature of isolated bilateral absence of SVC. Bilateral absent SVC can have clinical implication, including pacemaker placements, central venous line placement, monitoring, and occasionally associated anomalies. We describe a case detected on fetal echocardiogram with bilateral absent SVC and structurally normal heart.