Role of cardiac MRI and CT in Fontan circulation

Abstract

A Fontan circulation is a series of palliative surgical procedures, which result in the diversion of the systemic venous return into pulmonary arterial circulation without passing through a ventricle. It is one of the available surgical strategies for patients with cardiac defects that preclude a successful bi-ventricular repair, which encompass a range of complex anatomy. This surgical repair has gone through a series of modifications since the concept was introduced in 1971. Echocardiography remains a vital tool in assessing patients with Fontan circulations but its limitations are well recognised. Cross-sectional imaging modalities such as cardiac MRI and CT are essential components in the systematic clinical evaluation of these patients. The purpose of this review is to understand the information that can be obtained with each cross-sectional modality as well as highlight the challenges that each modality faces.

Pulsatility Index in Different Modifications of Fontan Palliation: An Echocardiographic Assessment

“… 5) 6) 9) Experimental studies have shown that pulsatile flow has an undeniable impact on the growth of great PA branches and pulmonary capillary system. 10) 11) 12) Moreover, noninvasive methods including magnetic resonance 2) 13) and echocardiographic imaging have been used to measure the PI in Fontan circulation. Although there are some limitations to achieve the optimal Doppler tracing and also obligatory assumptions for simple calculation, Doppler-derived PI seems to be a reproducible technique in Fontan palliated population.…”

Fontan Circuit Thrombus in Adults: Often Silent, Rarely Innocent

“…8 The hazard of over-calling Fontan thrombus or pulmonary embolism due to slow contrast mixing and incomplete opacification is well described. 17,18 In their informative article about the role of CMR and CT imaging in Fontan patients, Yeong et al explain that adequate imaging requires more time in the scanner and more contrast than is usual for general cardiac studies. 17 Time factors are important for work flow and because the kidney is also affected by chronic exposure to Fontan physiology, additional consideration must be given to the risks of contrast.…”

“…17,18 In their informative article about the role of CMR and CT imaging in Fontan patients, Yeong et al explain that adequate imaging requires more time in the scanner and more contrast than is usual for general cardiac studies. 17 Time factors are important for work flow and because the kidney is also affected by chronic exposure to Fontan physiology, additional consideration must be given to the risks of contrast. 19 Most patients in the study by Sathananthan et al underwent CT (78%) imaging instead of CMR (22%), 8 and, although not discussed by the authors, this probably reflects another barrier to routine cross-sectional imaging in this population.…”

“…Degrading artifacts caused by vascular coils, fenestration closure devices, and epicardial or transvenous pacemaker systems are limiting factors in the use of CMR in Fontan patients. 17,18 If regular cross-sectional imaging becomes standard of care, we will certainly expose the adult Fontan population to more ionizing radiation. Taking all of this and cost into account, perhaps the results of Sathananthan et al would better be considered an argument for an individualized imaging plan for every Fontan patient with attention given to baseline risk factors such as age and type of Fontan circuit, as well as to the risks and benefits of the various imaging techniques at our disposal.…”

The Profile of an Adult with Congenital Heart Disease

“…In Eisenmenger´s syndrome, the development of myocardial fibrosis is closely related to the generation less strength, symptoms such as fatigue or palpitations are attributed to the CHD itself, and the real new HF signs and symptoms are masked by the underlying CHD. A more objective assessment with diagnostic studies such as oxygen consumption during a stress test, 3D echocardiography (Figure 4) or functional MR, which measure the ejection fraction more precisely, is a more adequate and recommended method for measuring ACHDs´ functional capacity [22][23][24][25].…”