Chest X Rays Lecture Powerpoint Flashcards
X ray definition
Form of electromagnetic radiation similar to light but has higher energy and can pass thru most objects, passes thru detector (radiograph) on the other side of the patient and an image shows “shadows” formed by objects in the path
More dense tissue appears more ___ on x ray, while less dense tissue and air appears more ____
white, black
Radiolucent vs radiopaque/radiodense
-The degree to which a structure allows x rays to pass thru producing a more black color determines its radiolucency, while structures that block x rays producing less blackening are defined as radiopaque
Things that can affect image quality of an x ray (4)
- thickness of object
- motion artifact (creates blurring)
- scatter (determines contrast to allow differentiation of structures
- distortion (needed area of interest as close to perpendicular to image as possible
The further an object is from x ray film, the ____ the magnification which ____ the image
greater, distorts
3 primary checklist items to reading an x ray
1) correct patient using identifiers
2) correct date
3) comparison studies
RIPE acronym for x rays
Rotation
Inspiration
Projection
Exposure
Rotation - x ray film quality
Determined by identifying the medial ends of the clavicles which should be equidistant from the spinous processes
Inspiration - x ray film quality
- Determined by counting # of ribs above diaphragm, anterior ends of ribs 5-7 should be visible above diaphragm in the mid clavicular line, if there are more than that it indicates hyperinflation, and if there are fewer then inadequate inspiration
- Expiratory film will only have 3 ribs or so intersect the diaphragm at mid clavicular line
Projection - x ray film quality
Most of time going to get a PA (#1 choice) or AP, anatomy that is closest to the radiograph itself appears most true, PA sees the beam penetrate the patient’s back then anterior chest while AP is the opposite, both AP and PA projections are viewed as if looking at the patient face to face
Never consider a heart size enlarged on an x ray if looking at a….
…AP view x ray
Exposure - x ray film quality
Determined by being able to see left hemidiaphragm visible to the spinous process and vertebrae visible behind the heart
Systematic approach to reading a chest film
- Airway
- Breathing
- Cardiac
- Disability
- Exposure
Airway (systematic approach to reading a CXR)
- Trachea should be centrally located, pushing of trachea to opposite side indicates pleural effusion and tension pneumothorax, pulling of trachea to same side indicates atelectasis or non tension pneumothorax
- Bronchus carina should be visible
- Hila enlargement is due to different pathologies, bilateral might be sarcoidosis, unilateral might be malignancy
Breathing (systematic approach to reading a CXR)
- Lungs, assess zones in each 3rd of lung and look for good lung markings, increased airspace shadowing in an area of the lung suggests pathology (consolidation or malignancy which is more rounded), complete absence of lung markings with a lung field should raise suspicion of pneumothorax
- pleura not normally visible in healthy individuals
- right hemidiaphragm should be elevated above left, costophrenic angles should be sharp
Pneumoperitoneum
Evidenced on a CXR with air pocket between diaphragm (other than the gastric bubble) that is a medical emergency
Cardiac (systematic approach to reading CXR)
- Cardio thoracic ratio on PA view only, should be <50%
- heart borders should be well defined (silhouette sign if lost, depending on where border is lost can correlate clinically to lobe of lung)
- Aortic knob, loss of definition can be aneurysm, aortopulmonary window can be lost with lymphadenopathy
Disability (systematic approach to reading CXR)
-check all bones for fractures, dislocation, sublaxation, lesions, etc.
Exposure systematic approach to reading CXR)
- look for soft tissue abnormalities
- Looking for any tubes, lines, or devices
Patient history for CXR
-get a good surgical history!!!
In an AP film, the heart appears ____ because it is ____ so it falsely _____
larger, more anterior, enlarges
PA view vs AP view clavicle and rib orientation
PA view has flatter clavicles and more downturned ribs, AP has angled clavicles and more flat ribs
Best film to order to demonstrate axillary ribs
Oblique
Use of lateral decubitus in x ray film
Differentiate between fluid or air trapping (pleural effusion vs pneumothorax), fluid shifts with gravity while air does not
Posterior vs anterior ribs
Posterior ribs will be more horizontal and attached at the vertebrae while anterior will be angled downward and fade where cartilage present
