The role of cardiovascular magnetic resonance in pediatric congenital heart disease

Abstract

Cardiovascular magnetic resonance (CMR) has expanded its role in the diagnosis and management of congenital heart disease (CHD) and acquired heart disease in pediatric patients. Ongoing technological advancements in both data acquisition and data presentation have enabled CMR to be integrated into clinical practice with increasing understanding of the advantages and limitations of the technique by pediatric cardiologists and congenital heart surgeons. Importantly, the combination of exquisite 3D anatomy with physiological data enables CMR to provide a unique perspective for the management of many patients with CHD. Imaging small children with CHD is challenging, and in this article we will review the technical adjustments, imaging protocols and application of CMR in the pediatric population.

Figure 1

CMR set-up for paediatric general anaesthetic cases. View of the MR scanner room showing the anesthetic machine (A) and monitoring equipment (B). Ventilation tubing and leads from both pieces of equipment pass through a small opening in the wall (C) into the control room, so that the anesthetist can control breath-holding and monitor the patient from within the control room.

Figure 2

Aortic coarctation. A. 'Black-blood' oblique sagittal view showing discrete, tight coarctation at the aortic isthmus (arrow). B. 3D, contrast-enhanced CT angiogram showing mildly narrowed bare metal stent (arrow) that partially overlies the left subclavian artery origin. The arrowhead shows a subtle pseudo-aneurysm at the distal end of the stent. C. 3D, contrast-enhanced MR angiogram showing aortic arch hypoplasia and coarctation with a 'jump' by-pass graft posteriorly (arrow). D. 3D, contrast-enhanced MR angiogram showing large pseudo-aneurysm (arrowhead) after previous patch angioplasty repair. The true lumen is shown posteriorly (arrow).

Figure 3

A. Coronal view from a contrast-enhanced MR angiogram showing a modified BT shunt (arrowhead). It originates from the innominate artery and inserts into a dilated right pulmonary artery. B. 3D, contrast-enhanced MR angiogram viewed from left posterior lateral showing several major aorto-pulmonary collateral arteries (MAPCAs). The arrow shows the largest MAPCA to the right lung.

Figure 4

Repaired tetralogy of Fallot. A. 3D rapid prototyping models of the right ventricular outflow tract, pulmonary trunk and branch pulmonary arteries (reconstructed from 3D, contrast-enhanced MR angiogram data) from 12 patients with tetralogy of Fallot, all repaired in infancy and imaged 12-15 years later. Note the wide variation in morphology, size and narrowings. B. End-diastolic, balanced-SSFP, mid-ventricular, short-axis view showing severely dilated right ventricle (RV), flattened septum and small left ventricle (LV). C. (sagittal) &D. (axial), end-systolic, balanced-SSFP images of an aneurismal right ventricular outflow tract (arrow).

Figure 5

Transposition of the great arteries - Atrial switch (Senning or Mustard) operation. All images taken from frames of balanced-SSFP data. A. Oblique sagittal view through the ventricular outflow tracts showing the aorta arising anteriorly from the right ventricle (RV) and the pulmonary trunk posteriorly form the left ventricle (LV). B. Oblique coronal view through the systemic venous baffle, with both the SVC and IVC directed to the left atrium and then to the LV. C. Oblique axial view showing the pulmonary venous baffle (arrow) connecting the pulmonary veins to the right atrium and then RV. D. Oblique coronal view showing SVC baffle narrowing (arrow).

Figure 6

Transposition of the great arteries - Arterial switch operation. A. Axial reformat from contrast-enhanced MR angiogram &B. 3D, contrast-enhanced MR angiogram. Both A and B show Lecompte maneuver with the pulmonary artery anterior to the ascending aorta (AAo) with the right (RPA) and left pulmonary arteries passing either side of the aorta, note descending aorta (DAo). C. (axial reformat from contrast-enhanced MR angiogram) &D. (3D, contrast-enhanced MR angiogram) Showing alternative arterial switch operation, with the main pulmonary artery (arrow) seen to pass on the right side, between the superior vena cava (SVC), and aorta.

Figure 7

Hypoplastic left heart syndrome. A. End-diastolic, balanced SSFP, 4 chamber-view showing hypoplastic left ventricle (LV). Pulmonary venous return passes from left atrium to the right atrium, via a large atrial septostomy. B. 3D, contrast-enhanced MR angiogram after Stage 1, Norward operation, with a modified BT shunt (arrowhead) supplying the pulmonary arteries [153]. Note the hypoplastic native ascending aorta (arrow). C. 3D, contrast-enhanced MR angiogram after Stage 2 bi-directional cavo-pulmonary connection operation. This connects the SVC to the branch pulmonary arteries (pale blue). Again arrow shows hypoplastic native ascending aorta. D. 3D, contrast-enhanced MR angiogram after Stage 3, total cavo-pulmonary connection operation. This further connects the IVC into the pulmonary circulation (pale blue).

Figure 8

Examples of cardiomyopathies. A. 4-chamber, balanced-SSFP view in hypertrophic cardiomyopathy. Note the marked thickening of the septum with compression of the RV cavity. B. 4-chamber, balanced-SSFP view in left ventricular non-compaction. Note the arrowheads show areas of thin compacted myocardium. C. 4-chamber, late gadolinium enhancement (LGE) image in idiopathic dilated cardiomyopathy. Note no LGE. D. Short-axis, LGE image in a patient with critical aortic stenosis, restrictive cardiomyopathy secondary to global, sub-endocardial fibrosis.

Figure 9

Hybrid CMR/cardiac catheterization laboratory. Fish-eye view of a hybrid CMR/cardiac catheterization lab - The bi-plane catheter lab (left) is connected to the MR scanner room (right), via a set of sliding doors (open). The pedestal of the catheter table slides toward the MR scanning room to join with the MR scanner table. The patient then slides across between the two tabletops, using Miyabi table technology (Siemens AG).

Figure 10

Real time data. Short-axis ventricular volumes (top) and flow data (bottom) acquired during increasing exercise within the MR scanner (0, 4, 8, 12W). Because the data is acquired in real-time, there is no need for the patient to attempt breath-holding during peak exercise, which is often difficult to achieve.