Complex adult congenital heart disease on cross-sectional imaging: an introductory overview

Abstract

Congenital heart disease is the most common group of congenital pathology. Over the past few decades, advances in surgical treatment have resulted in a rising population of adult patients with repaired complex congenital heart disease. Although the quality of life has greatly improved, a significant proportion of morbidities encountered in clinical practice is now seen in adults rather than in children. These patients often have significant haemodynamic pathophysiology necessitating repeat intervention. CT and MRI are excellent imaging modalities, which help elucidate potential complications that may need urgent management. Although imaging should be performed in specialised centres, occasionally patients may present acutely to emergency departments in hospitals with little experience in managing potentially complex patients. The purpose of this article is to provide an introductory overview to the radiologist who may not be familiar with complex congenital heart disease in adult patients. This educational review has three main sections: (1) a brief overview of the post-operative anatomy and surgical management of the most common complex conditions followed by (2) a discussion on CT/MRI protocols and (3) a review of the various complications and their CT/MRI findings.

Multimodality Imaging Assessment of Tetralogy of Fallot: From Diagnosis to Long-Term Follow-Up

“…To trigger the scan, bolus tracking is favoured, with manual tracking preferred over automatic tracking. Adult protocols typically use high tube potential (100 kV to 120 kV) to minimise image noise, while paediatric protocols utilise a lower dose (70-80 kV) unless the child is overweight [60,65,66]. Cardiac gating, employing prospective electrocardiogram (ECG) triggering or retrospective ECG-gating, is used to reduce motion artefacts and enable functional assessment.…”

“…For complex congenital heart disease cases requiring high-definition imaging, a "combo" CT protocol may be chosen, consisting of a limited ECG-triggered scan focusing on the region of interest, followed by a non-gated spiral examination of the entire thorax during the venous phase [67,68]. Scanners are equipped with various dose reduction techniques, including anatomy-based tube current modulation and iterative reconstruction algorithms [65,67,68].…”

“…TOF patients may have associated coronary artery anomalies. CCT can potentially visualise the coronary arteries, aiding in the detection of abnormalities such as coronary artery anomalies or stenosis [64,65,71]. It is also ideal for assessing aortic arch and great vessel origins, like anomalous venous drainage or anomalous coronary origin, that should be known prior to surgery [68,71,72].…”

“…In postoperative patients, CCT can be used to quantify ventricular volumes, detect postsurgical complications, and plan for repeat interventions. CCT represents a practical alternative when echocardiography and CMRI are not indicated or suboptimal and is preferred for assessing graft material, calcifications, or stents in the conduit [64,65]. CCT in infants could also be used to evaluate anatomical relationships with the sternum and the chest after initial surgical reconstruction and to plan sequential stages of initial repair [61,73].…”

“…CCT in infants could also be used to evaluate anatomical relationships with the sternum and the chest after initial surgical reconstruction and to plan sequential stages of initial repair [61,73]. After complete repair of TOF, common postoperative complications such as RVOT dilatation, residual VSD, residual or recurrent RVOT stenosis, residual or recurrent PA stenosis, conduit stenosis, aortic dilation, stents, and implanted devices could be easily highlighted by CCT, as well as the anatomical assessment prior to transcatheter pulmonary valve replacement planning or redo sternotomy [61,[64][65][66]74]. While CCT provides excellent anatomical details, it may have limitations in evaluating the dynamic changes and hemodynamic consequences of TOF.…”