Congenital heart diseases: post-operative appearance on multi-detector CT-a pictorial essay

Don't skip a beat! Critical findings in imaging studies performed in adults with congenital heart disease

With ongoing advances in both medical and surgical management, the population of adults with congenital heart disease (CHD) continues to grow each year and has surpassed the number of pediatric cases. These adult patients will present to adult emergency departments with increasing frequency. Adults with CHD are at increased risk of developing not only cardiovascular complications, such as aortic dissection and thromboemboli, but also abdominopelvic and neurologic processes at younger ages. These individuals are also more likely to develop less urgent but clinically significant complications including end-organ dysfunction, baffle leaks, or bleeding collateral vessels. Ultimately, imaging can play a critical role in determining the triage, diagnosis, and management of adult CHD patients. To accomplish this goal, radiologists must be able to distinguish acute and chronic complications of treated CHD from benign processes, including expected post-surgical changes or imaging artifacts. Radiologists also need to be familiar with the various long-term risks and complications associated with both treated and untreated forms of CHD, particularly those in adults with complex lesions.

Pediatric Cardiovascular Computed Tomography: Clinical Indications, Technique, and Standardized Reporting. Recommendations From the Cardiothoracic Taskforce of the European Society of Pediatric Radiology

Congenital heart diseases affect 1% of all live births in the general population. The prognosis of these children is increasingly improving due to advances in medical care and surgical treatment. Imaging is also evolving rapidly to assess accurately complex cardiac anomalies prenatally and postnatally. Transthoracic echocardiography is the gold-standard imaging technique to diagnose and follow-up children with congenital heart disease. Cardiac computed tomography imaging plays a key role in the diagnosis of children with congenital heart defects that require intervention, due to its high temporal and spatial resolution, with low radiation doses. It is challenging for radiologists, not primarily specialized in this field, to perform and interpret these studies due to the difficult anatomy, physiology, and postsurgical changes. Technical challenges consist of necessary electrocardiogram gating and contrast bolus timing to obtain an optimal examination. This article aims to define indications for pediatric cardiac computed tomography, to explain how to perform and report these studies, and to discuss future applications of this technique.

Pictorial Essay: Understanding of Persistent Left Superior Vena Cava and Its Differential Diagnosis

Persistent left superior vena cava (PLSVC) is a rare congenital, thoracic, and vascular anomaly. Although PLSVCs generally do not have a hemodynamic effect, several types of PLSVC and some cardiac anomalies may manifest with clinical symptoms. The presence of PLSVC can render catheterization via left subclavian access difficult when placing a pacemaker or central venous catheter. As such, recognizing a PLSVC that is typically incidentally discovered can prevent complications such as vascular injury. Differentiating vessels found in a similar location as PLSVC is necessary when performing thoracic vascular procedures. This pictorial essay explains the multi-detector CT findings of a PLSVC, and provides a summary of other blood vessels that require differentiation during thoracic vascular procedures.

Assessment of superior cavo-pulmonary anastomoses (Glenn shunt) by cardiac magnetic resonance imaging in comparison with multi-slice computed tomography

Background

Multi-slice computed tomography (MSCT) angiography is the gold standard imaging modality to evaluate the patency of Glenn shunt and the presence of veno–veno collaterals. The goal of this study is to evaluate the ability of two cardiac magnetic resonance imaging (MRI) techniques to assess the patency of Glenn shunt and the presence of veno–veno collaterals compared to MSCT angiography.

Results

Patients with Glenn shunt had MSCT angiography and cardiac MRI using two techniques: TWIST (Time-resolved angiography With Stochastic Trajectories) and the three-dimensional (3D) post-contrast whole heart techniques. MSCT angiography and cardiac MRI images were post-processed for quantitative and qualitative assessment of Glenn shunt and veno–veno collaterals. Our study included 29 patients (17 male, 59%) with Glenn shunt, the median age was 22 years (range 3–36 years). 3D post-contrast whole heart images give similar results compared to MSCT angiography results in the evaluation of Glenn shunt and veno–veno collaterals, 100% agreement in Glenn shunt visualization and agreement was 86.2% in the detection of veno–veno collaterals with a perfect agreement (kappa = 1) as regards their proximal connection to superior vena cava (SVC). While TWIST showed lower agreement compared to MSCT angiography results, 87.5% agreement in Glenn shunt visualization and agreement was 68.9% in the detection of veno–veno collaterals with poor agreement (kappa = 0.266) as regards their proximal connection to SVC.

Conclusions

3D post-contrast whole heart MRI images have similar results as MSCT angiography in the evaluation of superior cavo-pulmonary anastomosis and can be a good and safer alternative to MSCT angiography.

Cardiac computed tomography angiography in the pre-operative assessment of congenital heart disease in Thailand

Introduction

Cardiac computed tomography angiography (CCTA) plays a vital role in clinical practice in evaluating patients with congenital heart disease (CHD) when the information from echocardiography is equivocal.

Aim

To test the hypothesis that CCTA has significantly value for pre-operative evaluation of congenital heart disease and practicality in the diagnosis and management of congenital heart disease patients at our tertiary care academic hospital.

Material and methods

We studied a total of 78 congenital heart disease patients (median age: 4.5 years) who had undergone CCTA during the period January 2017 to October 2018 at our tertiary care academic hospital.

Results

The results were classified as diagnostic categories, and the impact of the procedure on strategizing management was analysed. In each group, the CCTA offered an advantage and provided specific clues for surgical or interventional management. In total, the sensitivity (97.5%), specificity (100%), positive predictive value (100%), negative predictive value (99.38%), and accuracy (99.5%) of CCTA, for which the significant findings were confirmed by surgical or cardiac catheterization, were excellent, with average exposure per CCTA study calculated at 1.41 (0.36–3.28) mSv.

Conclusions

CCTA is an excellent non-invasive modality for the evaluation of congenital heart disease patients, with an important diagnostic and decision-aiding role.

Pediatric Cardiothoracic CT Guideline Provided by the Asian Society of Cardiovascular Imaging Congenital Heart Disease Study Group: Part 2. Contemporary Clinical Applications

The use of pediatric cardiothoracic CT for congenital heart disease (CHD) was traditionally limited to the morphologic evaluation of the extracardiac thoracic vessels, lungs, and airways. Currently, the applications of CT have increased, owing to technological advancements in hardware and software as well as several dose-reduction measures. In the previously published part 1 of the guideline by the Asian Society of Cardiovascular Imaging Congenital Heart Disease Study Group, we reviewed the prerequisite technical knowledge for clinical applications in a user-friendly and vendor-specific manner. Herein, we present the second part of our guideline on contemporary clinical applications of pediatric cardiothoracic CT for CHD based on the consensus of experts from the Asian Society of Cardiovascular Imaging CHD Study Group. This guideline describes up-to-date clinical applications effectively in a systematic fashion.

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.

Persistent left superior vena cava: clinical importance and differential diagnoses

Persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly and may be a component of the complex cardiac pathologies. While it is often asymptomatic, it can lead to significant problems such as arrhythmias and cyanosis. Besides, it can cause serious complications during vascular interventional procedures or the surgical treatment of cardiac anomalies (CA). The clinical significance of PLSVC depends on the drainage site and the accompanying CA. In this article, we will describe the epidemiology, embryology, and anatomic variations of PLSVC. Possible accompanying CA and heterotaxy spectrum will be reviewed with the help of multidetector computed tomography (MDCT) images. Radiological pitfalls, differential diagnoses, and the clinical importance of PLSVC will be highlighted.

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.

Assessment of intracardiac and extracardiac anomalies associated with coarctation of aorta and interrupted aortic arch using dual-source computed tomography

To evaluate the value of dual-source computed tomography (DSCT) compared with transthoracic echocardiography (TTE) in assessing intracardiac and extracardiac anomalies in patients with coarctation of aorta (CoA) and interrupted aortic arch (IAA). Seventy-five patients (63 with CoA and 12 with IAA) who received preoperative DSCT and TTE were retrospectively studied. Intracardiac and extracardiac anomalies were recorded and compared by DSCT and TTE, in reference to surgical or cardiac catheterization findings. A total of 155 associated anomalies were finally found. Collateral circulation (56, 74.70%), patent ductus arteriosus (PDA; 41, 54.67%) were the most common anomalies. PDA, aortopulmonary window, and collateral circulation were more frequently present in patients with IAA than those with CoA (100% vs. 46.03%, 16.67% vs. 0%, and 100% vs. 69.84%, respectively, all p < 0.05). DSCT was superior to TTE in assessing associated extracardiac-vascular anomalies (sensitivity: 100% vs. 39.81%; specificity: 100% vs. 100%; positive predictive value: 100% vs. 100%; negative predictive value: 100% vs. 76.06%). Extracardiac-vascular anomalies, including collateral circulation and PDA, were the most common anomalies in patients with IAA and CoA. Compared with TTE, DSCT is more reliable in providing an overall preoperative evaluation of morphological features and extracardiac anomalies for surgical planning.

CT for Assessment of Thrombosis and Pulmonary Embolism in Multiple Stages of Single-Ventricle Palliation: Challenges and Suggested Protocols

The total cavopulmonary connection (TCPC), or Fontan procedure, diverts systemic venous blood directly into the pulmonary arteries and is the palliative surgery of choice for patients with a wide variety of congenital heart diseases with single-ventricle physiologic characteristics. Pulmonary embolism and thrombosis are known complications and are among the major causes of morbidity and mortality in patients after TCPC. Magnetic resonance (MR) imaging is usually performed for postoperative evaluation of patients after single-ventricle repair; however, screening for thrombosis or embolism with MR imaging is not always feasible because of the emergent nature of the clinical presentation or because of artifacts from metallic devices or coils. Computed tomographic (CT) angiography is an effective method for diagnosing pulmonary embolism in children. However, because of altered hemodynamics after single-ventricle palliation, there are unique challenges in achieving optimal opacification of the pulmonary arteries and Fontan circuit that can result in nondiagnostic CT angiographic studies or erroneous image interpretation. Radiologists should be familiar with the multiple stages of single-ventricle palliation, understand the technique for performing pulmonary CT angiography at each stage, and recognize common pitfalls in obtaining and interpreting pulmonary CT angiographic images in patients who have undergone single-ventricle repair. Online supplemental material is available for this article. (©)RSNA, 2016.

Contrast opacification on thoracic CT angiography: challenges and solutions

Contrast flow and enhancement patterns seen on thoracic CT angiography (CTA) can often be challenging and may often reveal more than is immediately apparent. A non-diagnostic CTA following the initial contrast injection can be secondary to many causes; these include both extrinsic factors, such as injection technique/equipment failure (iv cannula, power injector), and intrinsic, patient-related factors. Contrast pressure and flow graphs often contain useful information regarding the etiology of a non-diagnostic scan. Understanding these graphs will help the radiologist plan a repeat contrast injection to overcome the deficiencies of the first injection and thus obtain a diagnostic scan. The current review article outlines normal and abnormal intravenous contrast dynamics, discusses how to recognize etiologies of non-diagnostic scans, and ultimately addresses techniques to overcome obstacles towards obtaining normal contrast opacification of the target vessel. In addition, there are some life-threatening findings, which unless sought for, may remain hidden in plain sight.

Key Points

• Using contrast enhancement and flow patterns to identify the cause of a non-diagnostic CTA.

• Recognize life threatening causes of altered contrast dynamics such as cardiac asystole.

• Non-target vessel opacification may hold key to underlying pathophysiology.

Korean guidelines for the appropriate use of cardiac CT

The development of cardiac CT has provided a non-invasive alternative to echocardiography, exercise electrocardiogram, and invasive angiography and cardiac CT continues to develop at an exponential speed even now. The appropriate use of cardiac CT may lead to improvements in the medical performances of physicians and can reduce medical costs which eventually contribute to better public health. However, until now, there has been no guideline regarding the appropriate use of cardiac CT in Korea. We intend to provide guidelines for the appropriate use of cardiac CT in heart diseases based on scientific data. The purpose of this guideline is to assist clinicians and other health professionals in the use of cardiac CT for diagnosis and treatment of heart diseases, especially in patients at high risk or suspected of heart disease.

Volumetric Computed Tomography Angiography in the Evaluation of Mediastinal Fluid Collections following Congenital Cardiac Surgery

We present 3 patients with 4 causes of mediastinal fluid collection after congenital cardiac surgery in this extended case report. Volumetric computed tomography played an essential role in diagnosing causes and extent, relevant to subsequent management. Recent advances in volumetric computed tomography allow fast and accurate imaging of cardiovascular and extravascular structures in children with acceptable radiation dose, providing a powerful imaging tool for the evaluation of complications after congenital cardiac surgery.