Lecture 3: radiology & PFTs Flashcards
T/F
The PA and lateral are most common but AP done when a portable x-ray is required for patient on bed rest.
T
Heart can appear enlarged and its outline softer with the [which view] projection because the heart is further away from the x-ray plate.
AP
First step of analyzing chest radiography: identify details. Which are they
Patient’s name, ID #, age, date and time of film, patient’s position, view of film (PA, AP or lat)
Orient the film properly on the screen
Note presence of various lines and leads, i.e. chest tubes, ET tube, NG tube, EKG leads, central lines, pacemaker wires, etc.
Chest radiography: Step2 is ?
What info are we looking for?
- Evaluation of the radio-opaque bony structures
Normal film exposure - should see intervertebral spaces superimposed on the shadow of the treachea.
Thorax centered - sternoclavicular joints equal distance from the spines of thoracic vertebrae.
Ribs uniformly dense.
T/F
Over-exposed - ↑ Whiteness
F
Chest radiography:
Step is 3 ?
What info are we looking for?
- Evaluation of lung volumes:
Anterior end of ~5-7 ribs should be visible above the diaphragm in the mid-clavicular line.
x-rays:
If more ribs are apparent, what does it mean? If less are apparent?
If more ribs apparent above the hemi-diaphragm, inspiratory volume large or patient hyperinflated.
If fewer ribs apparent above the hemidiaphragm, inspiratory volume small or patient has restricted lung volumes.
Chest radiography:
Step 4?
What are we looking at?
- Evaluation of mediastinal structures:
Tracheal shadow should be in midline: vertical radio-lucent (black) shadow located over the cervical spinous processes that extends inferiorly below the clavicles.
Carina overlies the 4th thoracic vertebrae
Chest radiography:
Step 5?
What are we looking at?
- Evaluation of the heart and great vessels:
Heart shadow slightly to the (L) of center and in contact with the diaphragm.
Aortic knob (L) of midline.
Cardiothoracic ratio (CTR): ratio of heart width to chest width . if greater than 1:2 (50%) is considered abnormal.
Cardiophrenic angle: intersection of vertical curvature of the heart shadow and horizontal curvature of the hemidiaphragm.
example of something that make the cardiophrenic angle / costophrenic angle disapear?
Fluid, ex: pleural effusion
Chest radiography:
Step 6?
What are we looking at?
- Evaluation of the hemi-diaphragms:
(R) hemidiaphragm higher than the (L) - because liver is beneath it.
Can have gas bubbles beneath (L) hemidiaphragm because of stomach or splenic flexure.
Costophrenic angle: intersection between the lateral chest wall and diaphragm - should be sharply defined on both sides.
Chest radiography:
Step 7?
What are we looking at?
- Evaluation of lung fields and boundaries:
Lung boundaries: are normally in contact with the chest wall and diaphragm.
Pleura only visible when an abnormality is present i.e. pleural thickening, fluid or air in the pleural spaces.
Lung fields not completely radiolucent (black) but have faint vascular markings extending in a branch-like manner from the hilum out to lung periphery
What is The silhouette sign (5)
- is the profile of soft tissues superimposed on the lung fields.
- when absent is indicative of airspace disease or fluid-occupying lesions.
- density of atelectatic or pneumonic lungs is same densitiy as soft tissues.
- consolidation or collapse density similar to that of heart or muscle –
- image of the collapsed lung will become confluent with the heart or diaphragm and respective borders will be obliterated.
Résumé:
- when consolidation or atelectasis affects any portion of lung adjacent to the cardiac or diaphragmatic border, that border can no longer be visualized radiologically.
How can you identify a pneumothorax on x-ray?
Pneumothorax: vasculatue is in the lungs and collapse with the lungs if collapse
Spirometry: 3 caracteristics
Assesses mechanical state of the lungs
Flow or volume-displacement devices
Volume-time spirogram; FEV1 and FVC
