Technically Adequate Chest Radiograph Flashcards
(24 cards)
Five technical factors to determine if na chest xray is adequate
penetration inspiration Rotation Magnification Angulation
Penetration us adequate if?
You can see the thoracic spine thru the heart -> over penetration
Under penetration:
Left hemidiaphragm not visible en face
Pulmonary markings appear more prominent
Adequate inspiration
8-9 posterior ribs above the diaphragm
Poor inspiration results in?
Will compress and crowd the lung markings especially at the bases
No rotation of the body of the patient if
The position of the medial ends of each clavicle relative to the spinous process is “equidistant”
Pitfalls of excessive rotation
Hilum may appear larger on the side rotated
Distorted contours of the heart
Hemidiaphragm appear higher on the side rotated
The distance bet the xray and the pt in a portable is….
While on PA chest is…
40 inches and 72 inches respectively
Excessive angulation when..
The clavicles project at or above the posterior first ribs on frontal image
Difference between anterior and posterior ribs in image
Posterior: more immediately apparent to the eye en face
Each pair of posterior ribs attaches to the thoracic vertebral body
The posterior ribs are oriented more or less horizontally
Anterior:
Difficult to see
Oriented downward toward the feet
Anterior ribs attach to the sternum or each cartilage
Angulation
Clavicle normally has an ‘s shape and superimpose on the third or fourth rib
Magnification
AP films will magnify the heart slightly
Rotation
Spinous process should fall equidistant between the medial ends of the clavicles
Inspiration
Should see at least eight to nine posterior ribs
Penetration
Should see spine through the heart
Why look at lateral chest films?
Determines location of disease
Confirms presence of disease
Sees disease not present en face
Five key areas to look for on lateral chest films
Retrosternal clear spaces Hilar region Fissures Thoracic spine Diaphragm and post costophrenic sulci
On lateral the major fissure is located at
From the level if the fifth thoracic vertebrae to a point on the diaphragm a few cm behind sternum
Minor fissure on lateral xray
Lies at the level of fourth anterior rib on the right side only horizontally oriented
Fissure visible en face
Minor fissure
Thickening of a fissure when no other signs of fluid on chest is due to
Fibrosis
Small bony spurs along the margins of the vertebral bodies
Osteophytes
How to tell the right or left hemidiaphragm on lateral xray?
right: usually visible for its entire length front to back
Left: seen sharply posterior but silhouetted by the heart
Air in stomach or splenic flexure
It only takes about ….ml to blunt the posterior costophrenic angle on lateral film but takes …..ml on frontal films ( lateral costophrenic angles)
75 ml
250 to 300 ml
3 things to see before interpreting xrays
Is the study technically adequate, is it normal or abnormal, if abnormal what is your strategy for deciding what abnormality it is
