Recognizing adult heart disease. Flashcards
3 reasons that the heart can appear enlarged and does it appear larger on AP or PA radiograph?
- because it is (cardiomegaly) 2. pericardial effusion 3. extracardiac factor produces apparent cardiac enlargement (e.g., obesity, pregnancy, rotation, pectus excavatum) At full inspiration, heart is should be <50% internal diameter of thoracic cage. Remember, the heart will appear slightly LARGER on an AP chest radiograph because the X-ray beam enters anteriorly and exits posteriorly, and the heart is farther from the imaging surface, thus appearing magnified.
Normal amount of pericardial fluid (in mL) and location in which accumulation of fluid begins
Normally, there are 15-50 mL of fluid in pericardial space between parietal and visceral pericardial layers. Abnormal accumulations begin in the dependent portions of the pericardial space, which, when supine, is POSTERIOR to the LEFT ventricle.
How can you best evaluate cardiomegaly on a lateral chest radiograph?
Look at the space posterior to the heart and anterior to the spine at the level of the diaphragm. As the heart enlarges, the posterior border of the heart may extend to or even overlap the anterior border of the thoracic spine.
Key point about cardiac contour: ascending aorta.
Should normally not project farther to the right than right heart border (i.e., RA).
Key point about cardiac contour: aortic knob
<35 mm and will normally push trachea slightly to the right.
Key point about cardiac contour: normal left atrium
Does not contribute to heart border on non-rotated frontal chest radiograph.
Key point about cardiac contour: descending aorta
Parallels the spine and is barely visible on frontal radiograph. When it becomes tortuous or uncoiled, swings farther away from thoracic spine towards patient’s left. Note in the picture that the descending aorta is swinging too far to the left, and the ascending aorta is too far to the right. The aortic knob is also enlarged. This patient most likely has hypertension.
Most marked chamber enlargement occurs from what?
Volume overload, rather than pressure overload. Thus, the largest chambers produced by regurgitant valves, rather than stenotic valves. This is why the heart usually appears normal in size in early MS but larger in MR, etc.
Most common dx in hospitalized pts >65
CHF
4 key radiographic signs of pulmonary interstitial edema
Fluid in the fissures
Peribronchial cuffing
Pleural effusions
Thickening of interlobular septa
black arrowheads.
When interlobular septae become thickened due to accumulation of excess fluid (i.e., PCWP about 15 mm Hg), they are called Kerley B lines. They are found at lung bases at or near costophrenic angles and perpendicular to the pleural surface.
white arrows.
Mitral stenosis. Obstruction to the outflow of blood from LA leading to LA enlargement. Remember, since the ventricles respond much more to regurg, not stenosis, this must be chronic MS. Note also in the image that the upper lobe vessels became as large or even more prominent than lower lobe vessels –> pulm arterial HTN –> right HF.
Main pulmonary artery.
Type A aortic dissection. Intimal flap seen to traverse both ascending and descending aorta.
Type B aortic dissection. Normal appearing ascending aorta while an intimal flap is noted by the black line traversing the descending aorta.
