A dual contrast injection technique for multidetector computed tomography angiography of Fontan procedures

Abstract

Extracardiac and lateral tunnel Fontan palliations result in caval venous return to the branch pulmonary arteries without prior blood mixing in the right atrium. Single contrast injection techniques result in suboptimal pulmonary computed tomography angiography since blood streaming results in asymmetric pulmonary flow of injected contrast. We used a dual injection technique--dorsal foot vein and upper extremity vein to achieve optimal simultaneous opacification of the inferior and superior venae cavae and branch pulmonary arteries. The resulting dataset allowed for excellent 3D volume renderings and multiplanar reformat images useful for stenosis, aneurysm, and metal stent evaluation.

Comparison of Non-Gated vs. ECG-gated CT Angiography of Fontan Circulation in Patients with Implanted Stents in Pulmonary Branches

“…His study demonstrates that a 3-minute-delay scan is the most optimal protocol in Fontan patients for the detection of thrombus regardless of intravenous route or surgical technique used. (11,12,13) We think that visualization of in-stents restenosis using the one-minute delayed scan is optimal. The similar studies comparing dose reduction in ECG-gated and non-gated CT scan in Fontans with implanted stents haven't been published yet.…”

Assessment of Extracardiac and Intracardiac Anatomy by MD-CT

“…MD-CT images of pulmonary arteries may be misdiagnosed as pulmonary stenosis, because they may not be fully opacified with contrast media due to the lack of an appropriate venous mixing chamber (Fig. 4.27) [29,30]. For the diagnosis of atretic vessels such as ligaments by MD-CT, it should be recognized that such vessels cannot be opacified with contrast media [3].…”

Optimizing CT angiography in patients with Fontan physiology: single-center experience of dual-site power injection

“…2e4 In most cases, the superior vena cava (SVC) is directed towards the right lung and the inferior vena cava (IVC) is directed towards the left lung. 5 The present study evaluated patients with Fontan physiology, which includes a variety of cavopulmonary connections including the Glenn (SVC connected to the pulmonary artery), the lateral tunnel (IVC connected to the pulmonary artery via a prosthetic baffle and a portion of the lateral atrial wall), and the now favoured total extracardiac Fontan procedure with a tube graft or conduit connecting the venae cavae with the pulmonary arteries. 6 Normally, the right ventricle mixes opacified and unopacified blood prior to the pulmonary circulation ensuring homogeneous pulmonary artery filling.…”

“…14 The increased incidence of thromboembolic disease in patients with Fontan circulation is presumably related to sluggish passive flow resulting from an absent subpulmonary ventricular pump. 5,15 Research has also shown that patients are at increased risk of arterial and venous thrombosis as a result of an imbalance in procoagulant and anticoagulant factors related to Fontan physiology. 16 Additionally, patients are at markedly increased risk for arrhythmia as a result of increased atrial pressure and distention, which further increases the incidence of thromboembolic events.…”

“…In the present authors' experience, visualization of both pulmonary arteries in patients who have Fontan physiology is best achieved by power injection of contrast medium (4e5 ml/s) into both an upper and central lower extremity vein simultaneously, as one pulmonary artery can be supplied by the SVC and the other by the IVC. 5,19 Unfortunately, patients with complex CHD and variant postoperative pulmonary anatomy are routinely examined with standard single upper extremity injections, thereby diminishing the quality of their CT angiograms (Fig 1). The single injection often results in suboptimal studies that either cannot be interpreted or are interpreted incorrectly.…”