clues.53–55 As with postnatal echocardiography, color and pulsed-wave Doppler analysis can assist greatly in identifying venous obstruction Cardiac Catheterization and Traditional Angiography Cardiac catheterization and traditional angiography are rarely indicated in this era If performed, they will document the pathophysiology already indicated The pulmonary venous anatomy can almost always be delineated without invasive testing.28,51 Computed Tomographic Angiography and Magnetic Resonance Imaging Technologic advances in medical imaging have increased the utilization of CTA and MRI in the evaluation of patients with anomalous pulmonary venous connection.48,56 Given the inherent complexity involved in understanding the three-dimensional relationships in these patients, multiplanar imaging techniques such as MRI and CTA allows three-dimensional representations of complex anatomic relationships Pulmonary venous connections with a particularly tortuous course, as is often seen with infracardiac connection or drainage via the azygos system, can be difficult to follow by echocardiography These multiplanar modalities allow one to follow even the most tortuous vessels in a relatively simple fashion As early as 1991, Masui et al.57 found MRI to be superior to both echocardiography and conventional angiography in patients with TAPVC Since then numerous other authors have endorsed its utility in these patients.48,58–60 In addition to imaging of complex structures, MRI allows for functional data including flow quantification and volumetric analysis However, cardiac MRI requires a combination of technical expertise and knowledge of cardiac anatomy that is not readily available in all centers, and time-consuming scanning protocols along with the need for transition to “MRI safe” equipment limit the practicality of this imaging modality in the most critically ill infants High-resolution CTA using multidetector scanners has proven to be a highly accurate alternative in the diagnosis and characterization of anomalous pulmonary venous connections (Fig 28.19).61–64 Newer scanners have cut the scanning time to a few seconds or less, allowing most scans to be performed without sedation.34 Commercial software is readily available for threedimensional reconstruction of these datasets (along with datasets from magnetic resonance angiography [MRA]), permitting those with reasonable knowledge in congenital heart disease to manipulate the anatomy in such a way that is easily understandable In contrast to MRA, CTA allows for simultaneous threedimensional reconstructions of additional thoracic structures This feature makes it particularly useful in patients with a bronchopulmonary vise, in which the vertical vein is compressed between the bronchus and a pulmonary artery In critically ill patents, CTA can be performed in an expeditious manner with minimal time away from the intensive care unit and without a need to transition to specialized equipment This can be useful for patients who are on extracorporeal membrane oxygenation (ECMO).65 FIG 28.19 Three-dimensional reconstruction of a computed tomographic angiogram viewed from a posterior perspective In this patient with a cardiac form of totally anomalous pulmonary venous connection, all the pulmonary veins are seen entering the coronary sinus (CS) Note that the left upper and left lower pulmonary veins (LUPV and LLPV) join to form a common left pulmonary vein, which is a frequent finding even in normal hearts RLPV, Right lower pulmonary vein; RUPV, right upper pulmonary vein F, Feet; H, head; L, left; R, right Unlike what is seen with traditional angiography, MRA and CTA will display contrast in multiple structures simultaneously This is particularly useful in documenting mixed connections and clarifying spatial relationships in those with more complex anatomic arrangements (Fig 28.20) Instead of using multiple injections and catheter courses to search for each pulmonary venous connection, all connections can be located on one contrast injection On the other hand, traditional angiography is likely superior in identifying pulmonary venous drainage from areas of the lung where there is no pulmonary blood flow, as these newer modalities have no acceptable substitute for a pulmonary artery wedge angiogram When patients with suspected supracardiac drainage are being imaged, it may be useful to inject contrast from below the heart Assuming that the scan is performed with the first pass of contrast through the heart, as is standard procedure, any contrast in a venous structure above the heart can clearly be identified as pulmonary venous in origin (Fig 28.21) This is particularly useful when one is trying to differentiate a left superior caval vein from a vertical vein The converse can be applied to infracardiac connection (Fig 28.22)