FIG 38.20 Color flow mapping showing severe regurgitation across the morphologically (morph.) tricuspid valve Cardiac Catheterization and Angiography This is not usually necessary for diagnosis but may be necessary in situations where there are multiple ventricular septal defects that cannot clearly be seen using echocardiography The investigation of pulmonary hypertension in older patients and the evaluation and measurement of pulmonary vascular resistance may be necessary to establish operability Rarely, in those with pulmonary atresia, major aortopulmonary collateral arteries supply most of the blood to the lungs The origin and course of these arteries can more clearly be shown with angiography When anatomic repair is planned, such as the double switch procedure, coronary angiography may be helpful in delineating the anatomy of the coronary arteries When there has been prior construction of a systemic-topulmonary arterial shunt, or the pulmonary trunk has been banded to reduce the flow of blood to the lungs or to train the mLV (Fig 38.21), hemodynamic and angiographic data are required to demonstrate the anatomy of the pulmonary arteries and to show whether the mLV has been adequately trained so that it can support the systemic circulation.43 FIG 38.21 Angiogram showing a banded pulmonary trunk, the band having been placed to train the morphologically (morph.) left ventricle Computerized Axial Tomography and Magnetic Resonance Imaging These modalities are increasingly used in conjunction with echocardiography to evaluate the morphology and hemodynamics of patients with congenitally corrected transposition In infants and small children, a general anesthetic is usually necessary if these scans are to provide accurate data, but more modern systems and faster computing power may well provide accurate data without the requirement for anesthesia Magnetic resonance imaging is particularly helpful in cases of pulmonary stenosis/atresia and VSD in assessing the size of the right ventricle and suitability for surgical repair Three-dimensional reconstructions and even three-dimensional printing are increasingly used to aid surgical decision-making Magnetic resonance imaging is also of value in the postoperative situation to check the patency of the venous (Fig 38.22) and arterial pathways subsequent to reconstructive surgery The bedrock for evaluation of patients with congenitally corrected transposition of all ages, nonetheless, is echocardiography, with other modalities being used to fine-tune the diagnosis and hemodynamics FIG 38.22 Magnetic resonance images showing the results of the Senning operation as performed to redirect the atrial venous returns as part of anatomic correction (A) Short-axis cut (B) Angulated cut producing a four-chamber section LV, Left ventricle; morph., morphologically; RA, right atrium; RV, right ventricle Differential Diagnosis It should currently be always possible in all patients to make a clear diagnosis of congenitally corrected transposition and to identify all associated lesions Some