Cardiac MR imaging in congenital heart disease

Echocardiogram-gated multislice spiral CT in functionally univentricular heart following long-lasting Waterston-Cooley anastomosis

Waterston-Cooley anastomosis may be carried out in patients with tricuspid atresia to provide pulmonary perfusion. It is associated with several complications, including preferential blood flow to the right lung, hypoplasia of the left pulmonary artery, obstruction of the anatomosis or rupture of pulmonary aneurysms. We study a patient with thrombosis in the pulmonary arteries following surgical construction of a Waterston shunt in childhood. Imaging findings and clinical symptoms are discussed with emphasis on echocardiogram-gated multislice spiral CT.

Coarctation of the aorta: pre and postoperative evaluation with MRI and MR angiography; correlation with echocardiography and surgery

AIMS

To compare MRI and MRA with Doppler-echocardiography (DE) in native and postoperative aortic coarctation, define the best MR protocol for its evaluation, compare MR with surgical findings in native coarctation.

MATERIALS AND METHODS

136 MR studies were performed in 121 patients divided in two groups: Group I, 55 preoperative; group II, 81 postoperative. In group I, all had DE and surgery was performed in 35 cases. In group II, DE was available for comparison in 71 cases. MR study comprised: spin-echo, cine, velocity-encoded cine (VEC) sequences and 3D contrast-enhanced MRA.

RESULTS

In group I, diagnosis of coarctation was made by DE in 33 cases and suspicion of coarctation and/or aortic arch hypoplasia in 18 cases. Aortic arch was not well demonstrated in 3 cases and DE missed one case. There was a close correlation between VEC MRI and Doppler gradient estimates across the coarctation, between MRI aortic arch diameters and surgery but a poor correlation in isthmic measurements. In group II, DE detected a normal isthmic region in 31 out of 35 cases. Postoperative anomalies (recoarctation, aortic arch hypoplasia, kinking, pseudoaneurysm) were not demonstrated with DE in 50% of cases.

CONCLUSIONS

MRI is superior to DE for pre and post-treatment evaluation of aortic coarctation. An optimal MR protocol is proposed. Internal measurement of the narrowing does not correspond to the external aspect of the surgical narrowing.

A review of the complementary information available with cardiac magnetic resonance imaging and multi-slice computed tomography (CT) during the study of congenital heart disease

The incidence of congenital heart disease is approximately 4-6 per 1000 new births; however, the number of people living with congenital heart disease (CHD) is increasing, because of improved diagnosis, medical, and surgical management. While echocardiography continues to be the mainstay of non-invasive imaging, cardiac MRI (cMRI) and computed tomography (CT) have taken on increasing roles in the diagnosis of congenital heart disease in infants, children, and importantly, adults who may have limited echocardiographic windows, especially if post-operative. Cardiac MRI and multi-slice CT can complement the diagnostic information obtained by echocardiography and invasive cardiac catheterization. Post-operative imaging of CHD is especially enhanced by the spin echo MRI techniques, while gradient cine echo MRI imaging allows functional information that is not encumbered by geometric assumptions. Phase contrast (velocity encoding) cardiac MRI data can provide information about flow, allowing accurate determination of regurgitation and shunt volume. Gadolinium enhanced cMRI or three-dimensional reconstructed images from multi-slice CT angiography allow excellent delineation of vascular structures in complex heart disease. Coronary imaging, while possible with both modalities, appears more facile with fast CT imaging. This article reviews the literature to provide an assessment of the special techniques and considerations needed during the conduct of cardiac MRI/MRA and multi-slice CT examinations during the diagnosis of congenital heart disease in pediatric and adult patients.

Coronary artery imaging in grown up congenital heart disease: complementary role of magnetic resonance and x-ray coronary angiography

BACKGROUND

There is a high incidence of anomalous coronary arteries in subjects with congenital heart disease. These abnormalities can be responsible for myocardial ischemia and sudden death or be damaged during surgical intervention. It can be difficult to define the proximal course of anomalous coronary arteries with the use of conventional x-ray coronary angiography. Magnetic resonance coronary angiography (MRCA) has been shown to be useful in the assessment of the 3-dimensional relationship between the coronary arteries and the great vessels in subjects with normal cardiac morphology but has not been used in patients with congenital heart disease.

METHODS AND RESULTS

Twenty-five adults with various congenital heart abnormalities were studied. X-ray coronary angiography and respiratory-gated MRCA were performed in all subjects. Coronary artery origin and proximal course were assessed for each imaging modality by separate, blinded investigators. Images were then compared, and a consensus diagnosis was reached. With the consensus readings for both magnetic resonance and x-ray coronary angiography, it was possible to identify the origin and course of the proximal coronary arteries in all 25 subjects: 16 with coronary anomalies and 9 with normal coronary arteries. Respiratory-gated MRCA had an accuracy of 92%, a sensitivity of 88%, and a specificity of 100% for the detection of abnormal coronary arteries. The MRCA results were more likely to agree with the consensus for definition of the proximal course of the coronary arteries (P<0.02).

CONCLUSIONS

For the assessment of anomalous coronary artery anatomy in patients with congenital heart disease, the use of the combination of MRCA with x-ray coronary angiography improves the definition of the proximal coronary artery course. MRCA provides correct spatial relationships, whereas x-ray angiography provides a view of the entire coronary length and its peripheral run-off. Furthermore, respiratory-gated MRCA can be performed without breath holding and with only limited subject cooperation.

Morphologic and functional evaluation of congenital heart disease by magnetic resonance imaging

Magnetic resonance imaging (MRI) has evolved sufficiently to be recognized as a useful complementary noninvasive method to echocardiography in the evaluation of congenital heart disease (CHD). In some cases, MRI is superior to other imaging modalities, particularly in the evaluation of thoracic aortic anomalies and in defining the anatomy of central pulmonary arteries; it is also the procedure of choice in the postoperative follow-up of patients with CHD. Recent technological advances permit not only morphological evaluation (provided by spin-echo and MR angiographic techniques) but functional and flow information (provided by fast cine-GE and velocity-encoded sequences), causing it to be recognized by pediatric cardiologists and cardiac surgeons as an unavoidable technique for pre- and postoperative evaluation of some CHD. This review describes the various techniques used in the evaluation of CHD with emphasis on recent developments as well as recognized clinical applications. J. Magn. Reson. Imaging 1999;10:639-655.