CHAPTER 28: Radiology

THE CHEST X-RAY IN THE ECHO LAB

• A phone call may come to the lab asking for an echo because of a finding on a chest x-ray. The following is a very simple but practical guide.

• Lungs: The vascular markings of the lungs may become more prominent. Echo looks for cardiac shunts or causes of left heart failure.

• Cardiac size: The cardiac silhouette may change in size and contour. Echo looks for cardiac chamber size, wall thickness, and function.

• An echocardiographer should be familiar with the rules for normal lung markings on the chest x-ray: The pulmonary vessels branch out in symmetric fashion. They are sharply defined. As they branch out to the periphery, each successive set of branches is slightly smaller—just like in a tree. Normal pulmonary vessels are larger in the lower lobes than in the upper lobes.

• Pericardial calcifications can be found on the chest x-ray of patients with pericardial constriction. The calcifications may be easier to spot in the lateral films. The calcifications may appear as a hoop, as a band, or as a sheet of calcium.

• Cardiac fluoroscopy can be used to study the function of mechanical prosthetic valves.

X-RAY SIGNS AND EPONYMS

• Vertical heart borders, clear lungs, prominent left pulmonary artery: pulmonic valve stenosis (easily confirmed on echo).

• Pulmonary vessel pruning in pulmonary hypertension. There is a sharp decrease in the size of the vascular shadows in the outer regions of the lung fields.

• Rib notching: coarctation of the aorta.

• Waterfall hilum: dilated pulmonary trunk with elevation of the right pulmonary artery due to increased pulmonary flow in a congenital shunt (transposition, tricuspid atresia, truncus arteriosus).

• Shmoo-shaped cardiac silhouette: Left ventricular hypertrophy or enlargement (easy to confirm with echo). The Shmoo was a comic strip creature drawn by cartoonist Al Capp.

• Boot-shaped heart: tetralogy of Fallot—the dilated right ventricle curves around the small left ventricle. The apex of the heart is pushed out and elevated. The cardiac shadow resembles a boot.

Source

• Aziz F, Abed M. Coeur en sabot. Cardiovasc J Afr. 2010;21:229–231.

• Right aortic arch: tetralogy of Fallot, or a vascular ring.

Source

• Etesami M, Ashwath R, Kanne J, et al. Computed tomography in the evaluation of vascular rings and slings. Insights Imaging. 2014;5:507–521.

• Butterfly or bat wing density of the lung fields: pulmonary edema.

Source

• Herrnheiser G, Hinson KF. An anatomical explanation of the formation of butterfly shadows. Thorax. 1954;9:198–210.

• Egg-on-a-string heart: In some patients with transposition of the great vessels, the cardiac shadow resembles an egg that is tilted so that its long axis lies in an oblique position.

Source

• Carey LS, Elliott LP. Complete transposition of the great vessels. Roentgenographic ...