Cardiac Computed Tomography in Congenital Heart Disease

Computed tomography (CT) has emerged as a leading imaging modality in the evaluation of congenital heart disease (CHD). With ever-faster acquisition speed, decreasing radiation exposure, impeccable anatomic detail, optional functional data, and numerous post-processing tools, CT offers broad utility in CHD diagnosis, preoperative planning, and postoperative assessment. In this article, the far-reaching role of CT in CHD is reviewed, focusing on technical imaging considerations and key clinical applications.

Coarctation of the Aorta: Modern Paradigms Across the Lifespan

While coarctation of the aorta varies greatly in both severity and age at presentation, all patients are at increased risk of hypertension both before and after repair. Despite advances in knowledge about genetic etiologies, pathophysiologic mechanisms, and optimal repair strategies, patients with repaired coarctation of the aorta remain at increased risk of acquired cardiovascular disease. The aims of this review are to describe the management of coarctation of the aorta at all ages before and after repair, highlight pathophysiologic mechanisms of hypertension, and review long-term follow-up considerations.

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.

Computed tomography imaging of complications in postoperative cyanotic congenital heart diseases - A pictorial essay

Cross-sectional imaging plays an essential role in the diagnosis and management of various structural and functional changes that occur in the postoperative period after palliative or corrective surgical procedures performed for congenital heart diseases (CHD). Although echocardiography is the mainstay for the evaluation of CHD, it is limited by poor acoustic window post-surgery in addition to being operator dependent. Computed tomography (CT) allows for the comprehensive evaluation of the post-surgical anatomy and complications after repair for cyanotic CHD. Radiologists and cardiac imagers should be familiar with these expected changes after surgeries performed for various cyanotic CHDs, to obtain diagnostic quality cardiac CT images and to promptly recognise the abnormal post-operative appearances in this patient population. In this review, we describe the various CT features of complications that can be encountered after repair of cyanotic CHDs.

Cross-sectional imaging of congenital pulmonary artery anomalies

Congenital pulmonary artery (PA) anomalies comprise a rare and heterogeneous spectrum of disease, ranging from abnormal origins to complete atresia. They may present in early infancy or more insidiously in adulthood, often in association with congenital heart disease such as tetralogy of Fallot or other syndromes. In recent years, cross-sectional imaging, including computed tomography (CT) and magnetic resonance imaging (MRI), has become widely utilized for the noninvasive assessment of congenital PA diseases, supplementing echocardiography and at times supplanting invasive angiography. In this article, modern CT and MRI techniques for imaging congenital PA disorders are summarized. The key clinical features, cross-sectional imaging findings, and treatment options for the most commonly encountered entities are then reviewed. Emphasis is placed on the ever-growing role of cross-sectional imaging options in facilitating early and accurate diagnosis and tailored treatment.

Imaging of postoperative tetralogy of Fallot repair

Over the last years, the surgical techniques used to repair Tetralogy of Fallot as well as the cross-sectional cardiac imaging techniques have substantially improved. Now, the survival rate after surgical repair is more than 90% at 40 years old. A follow-up is needed and the imaging evaluation should be guided by the surgical techniques used. This article reviews the most common surgical procedures for a complete repair, the associated anatomic and hemodynamic complications and the role of cardiac imaging, mainly magnetic resonance imaging.

Multidetector CT assessment of partial anomalous pulmonary venous return in association with sinus venosus type atrial septal defect

Sinus venosus defects account for 15% of all atrial septal defects. They are frequently associated with partial anomalous pulmonary venous drainage of the right superior pulmonary vein into the superior vena cava (SVC). These defects require surgical correction and accurate pre-operative imaging assessment is critical. We present a case of sinus venosus atrial septal defect in which multidetector computed tomography (MDCT) angiography identified separate sites of pulmonary venous return.

Low-dose prospectively electrocardiogram-gated axial dual-source CT angiography in patients with pulsatile bilateral bidirectional Glenn Shunt: an alternative noninvasive method for postoperative morphological estimation

OBJECTIVE

To explore the clinical value of low-dose prospectively electrocardiogram-gated axial dual-source CT angiography (low-dose PGA scanning, CTA) in patients with pulsatile bilateral bidirectional Glenn shunt (bBDG) as an alternative noninvasive method for postoperative morphological estimation.

METHODS

Twenty patients with pulsatile bBDG (mean age 4.2±1.6 years) underwent both low-dose PGA scanning and conventional cardiac angiography (CCA) for the morphological changes. The morphological evaluation included the anatomy of superior vena cava (SVC) and pulmonary artery (PA), the anastomotic location, thrombosis, aorto-pulmonary collateral circulation, pulmonary arteriovenous malformations, etc. Objective and subjective image quality was assessed. Bland-Altman analysis and linear regression analyses were used to evaluate the correlation on measurements between CTA and CCA. Effective radiation dose of both modalities was calculated.

RESULTS

The CT attenuation value of bilateral SVC and PA was higher than 300 HU. The average subjective image quality score was 4.05±0.69. The morphology of bilateral SVC and PA was displayed completely and intuitively by CTA images. There were 24 SVC above PA and 15 SVC beside PA. Thrombosis was found in 1 patient. Collateral vessels were detected in 13 patients. No pulmonary arteriovenous malformation was found in our study. A strong correlation (R2>0.8, P<0.001) was observed between the measurements on CTA images and on CCA images. Bland-Altman analysis demonstrated a systematic overestimation of the measurements by CTA (the mean value of bias>0).The mean effective dose of CTA and CCA was 0.50±0.17 mSv and 4.85±1.34 mSv respectively.

CONCLUSION

CT angiography with a low-dose PGA scanning is an accurate and reliable noninvasive examination in the assessment of morphological changes in patients with pulsatile bBDG.

The Impact of Congenital Cardiovascular Malformations on the Assessment and Surgical Management of Infants with Cleft Lip and/or Palate

Objective

The purpose of this study was to assess the cardiac evaluation of cleft lip and/or palate patients, characterize their cardiovascular malformations, and determine the impact of cardiovascular malformations on surgical management.

Design

A single-institution retrospective study of 329 consecutive cleft patients was performed. Cardiovascular malformations were categorized according to involvement of cardiac septa, vasculature, and valves. Their impact on the need for cardiac surgery, timing of cleft repair, need for subacute bacterial endocarditis (SBE) prophylaxis, and the perioperative experience was evaluated.

Results

Ten percent (33/329) of cleft patients had a cardiovascular malformation, and 3% underwent cardiac surgery prior to cleft repair. Malformations of the septa, vasculature, and valves were present in 9%, 6%, and 2% of cleft infants, respectively. Murmur as a sign of structural cardiovascular disease was 79% sensitive and 97% specific. Cleft palate repair was delayed by 2 months in patients with a cardiovascular malformation ( P = .001). Subacute bacterial endocarditis prophylaxis was recommended, not recommended, or not specified by cardiology in 18%, 33%, and 48% of cleft patients with a cardiovascular malformation, respectively. Postoperative stay and surgical complications were not associated with cardiovascular malformation.

Conclusions

Even in the absence of a murmur, echocardiographic screening should be considered in infants with nonspecific signs of cardiovascular disease. Greater awareness of the guidelines for SBE prophylaxis is needed. Most cleft patients with a cardiovascular malformation do not require cardiac surgery and do not experience an increased rate of complications associated with cleft surgery.

MRI-guided ablation of wide complex tachycardia in a univentricular heart

Magnetic resonance imaging can be used for preprocedural assessment of complex anatomy for radiofrequency (RF) ablations, e.g., in a univentricular heart. This case report features the treatment of a young patient with a functionally univentricular heart who suffered from persistent sudden onset tachycardia with wide complexes that required RF ablation as treatment.

Carotid-subclavian bypass for subclavian steal syndrome following coarctation repair in infancy

A 19 year old man presented with dizziness that was exacerbated while using left arm. On investigation, subclavian steal syndrome (SSS) was diagnosed. He underwent left carotid to subclavian bypass with relief of symptoms. Subclavian steal syndrome, although rare, should be considered in the differential diagnosis in patients with the history of subclavian artery manipulation in the past in proper settings.

Cardiac MDCT in children: CT technology overview and interpretation

Cardiac multidetector computed tomography (MDCT) for congenital heart disease is a useful, rapid, and noninvasive imaging technique bridging the gaps between echocardiography, cardiac catheterization, and cardiac MRI. Fast scan speed and greater anatomic coverage, combined with flexible ECG-synchronized scans and a low radiation dose, are critical for improving the image quality of cardiac MDCT and minimizing patient risk. Current MDCT techniques can accurately evaluate extracardiac great vessels, lungs, and airways, as well as coronary arteries and intracardiac structures. Radiologists who perform cardiac MDCT in children should be familiarized with optimal cardiac computed tomography (CT) scan techniques and characteristic cardiac CT scan imaging findings.

[MRI for therapy control in patients with aortic isthmus stenosis]

Aortic isthmus stenosis is the most common congenital aortic anomaly and is often a problem for therapy surveillance. In addition to possible comorbidities (e.g. bicuspid aortic valve) it is accompanied by various middle and long-term complications depending on the primary choice of the therapeutic procedure. Magnetic resonance imaging (MRI) plays an important role for the mostly young patients in the control of the aortic isthmus stenosis and therapy because it is non-invasive and there is no X-ray exposure. Radiologists should be well-informed on the principles of the therapeutic procedure in order to be competent in the interpretation of MRI findings. Due to the continuous development of MRI technology, techniques for functional evaluation (e.g. dynamic MRA, 4D PC flow measurement) are increasingly becoming available in addition to high-resolution MR angiography (MRA), which could predict the risk of possible complications, such as aneurysms. However, in this aspect further studies are necessary. Interventional therapy with stents and stent grafts is often employed for the therapy of possible complications following an operation (aneurysms, restenosis) but because of massive metal artefacts the use of MRI is often sometimes severely limited.