Figure 18a. Tetralogy of Fallot. (a) CT scan shows a right ventricular outlet obstruction due to hypertrophy and anterosuperior displacement of the infundibular septum (arrows) and to hypertrophy of the anterior muscle bundles (*). (b) On an MIP image (right anterior oblique view) segmented for the right ventricle and pulmonary artery, the hypertrophic anterior muscle bundles (arrows) are seen to encroach on the right ventricular outflow tract, a finding that is best seen on this view.