Medical Imaging

Evaluate for Left Ventricle (LV) Enlargement
Evidence of an enlarged left ventricle can be as follows:

1. Displacement of cardiac apex inferiorly and posteriorly
2. Boot shaped heart
3. Rigler’s sign (on the lateral film from the junction of the inferior vena cava (IVC) and heart at the level of the diaphragm)

Measure 1.8 cm posteriorly and then 1.8 cm superiorly. If the cardiac shadow extends beyond this point then LV enlargement is suggested.

Evaluate for Left Atrium Enlargement
Evidence of an enlarged left atrium can be as follows:

1. Straightening of the left heart border
2. Increased opacity of the lower right side of a cardiovascular border (double heart border)
3. Elevation of the left main stem bronchus (specifically the upper lobe bronchus on the lateral film)

Heart Structures – Lateral View
Different visualization of heart structures.

Identify Structures – Lateral View
Identify heart chambers and vessels on a lateral view.
RA = right atrium RV = right ventricle LPA – left pulmonary artery RPA = right pulmonary artery LA = left atrium LV = left ventricle

Identify Structures – AP View
Identify heart chambers and vessels on an AP view.
Left Image: Depicts right-sided heart structures.
Right Image: Depicts left-sided heart structures.

RA = right atrium RV = right ventricle LA = left atrium LV = left ventricle

Heart Structures – AP View
Different visualization of heart structures.

In an adult, a good quality film will show a normal cardiothoracic ratio of 0.5. Conditions causing a ratio >0.5 are cardiomegaly (dilation and hypertrophy), pericardial effusion, small lung volumes or pectus excavatum. However, a ratio of <0.5 cannot rule out heart enlargement, because the lungs could also be hyperinflated.

Evaluate for Calcifications
Calcified areas are dense. Look for these regions in valves, vessels (coronary arteries) pericardium and walls of the LV (aneurysm/posterior infarct). To find valves on a lateral film draw a lline from the carina to the xiphoid and then draw lines to divide the heart into thirds. The valves should fall at the junction of these lines.