Lecture 3: CXR_interpret_STUDENT-2020-EDITED AL Flashcards
Justification for CXR
pneumonia (confirmation) immunosuppressed pt COPD w/acute exacerbation foreign body CHF aspiration pneumonia blunt trauma lung tumor chest pain suspected pneumothorax SOB (severe) hemoptysis pulmonary HTN PE interstitial lung ds ICU pt (adm, inv lines, ETT)
Basic Tissue Densities
• Black =
• Black – air
Basic Tissue Densities
• Dark gray =
• Dark gray – subcutaneous tissue, fat
Basic Tissue Densities
• Light gray =
• Light gray – soft tissue (muscles, heart, blood vessels, pus, etc)
Basic Tissue Densities
• Off white =
• Off white – bone
Basic Tissue Densities
• Bright white =
• Bright white – metal (pacemakers, surgical clips, bullets, etc)
Supine
• supine position limits ?
• ________ push is noted- (____________ contents)
• small pleural effusions will layer in ?- can easily be ?
• Be _______ interpreting supine films!
- supine position limits full inspiration
- cephalic push is noted- (liver and abdominal contents)
- small pleural effusions will layer in posterior pleural space- can easily be missed
- Be careful interpreting supine films!
Upright position
inspiration is ?
inspiration is greater/better
Inspiration and Expiration
Good inspiration = ?
Hypoinflation= ?
Good inspiration = hemi diaphragm down to level of posterior 10th or 11th ribs.
Hypoinflation= dome at 7th rib
• PA (posteroanterior)
• AP (anteroposterior)
Can you explain the two terms????????????
PA: X-ray beam is entering/exiting = pt position = detector position = heart size = diaphragm =
AP: X-ray beam is entering/exiting = pt position = detector position = heart size = diaphragm =
Terminology
Position is TREMENDOUSLY important because the following might be affected:
- magnification
- organ position
- blood flow
- gravitational pull
Which view is most preferred?
Why? See other slides
PA & Upright
Well demarcated costophrenic angle + see other slides
Expiration usefulness
small pneumothorax: expiration will make the lung larger/smaller and more/less dense, and at the same time will relatively make the pneumothorax appear larger/smaller?
small pneumothorax: expiration will make the lung smaller and denser, and at the same time will relatively make the pneumothorax appear larger
Expiration usefulness
lodged foreign body: “ball-valve phenomenon” – air can move past the object during inspiration, but during expiration (the bronchus gets smaller) and air can not exit around the obj. As a result, the expiration image will show air trapping in the affected lung and a mediastinal shift will occur toward ?
lodged foreign body: “ball-valve phenomenon” – air can move past the object during inspiration, but during expiration (the bronchus gets smaller) and air can not exit around the obj. As a result, the expiration image will show air trapping in the affected lung and a mediastinal shift will occur toward the unaffected side
Pneumothorax =
supine vs upright?
Where is the first place to look for pneumothorax?
deep sulcus sign =?
Pneumothorax—air positioned between the visceral and parietal pleura
- trauma, subclavian venous catheter, liver biopsy
- spontaneous (bleb rupture)
- metastatic tumors
upright
Where is the first place to look for pneumothorax (UPPER)
deep sulcus sign = costophrenic angle getting deeper? (supine?) ~ look up!!!
Pleural effusion
Pleural effusion =
Look for:
Causes:
What is the preferred X-ray position (upright or supine)?
Pleural effusion—collection of fluid between the visceral and parietal pleura (~100 mLs to be detected on upright CXR)
Look for (reference image on pg 87 of reading):
blunting of costophrenic angles
increased basilar density (whiteness)
loss of normal lung-hemidiaphragm is noted
Causes: malignancies, pancreatitis (left-sided), cirrhosis (right-sided), CHF (bilateral), pneumonias (40%)
What is the preferred X-ray position? upright
Mediastinal shifts:
• Tension pneumothorax—the mediastinum is shifted toward the (affected, unaffected) side?
• Atelectasis—collapse of entire lung segment might result in severe volume loss. Will see mediastinal shift toward the (affected, unaffected) side?
• Airway obstruction—mediastinal shift toward the (affected, unaffected) side?
Mediastinal shifts:
• Tension pneumothorax—the mediastinum is shifted toward the unaffected side.
• Atelectasis—collapse of entire lung segment might result in severe volume loss. Will see mediastinal shift toward the affected side.
• Airway obstruction—mediastinal shift toward the unaffected side.
male vs female CXR?
• nipple shadows → men and women
• overlying breast tissue → accentuate pulmonary vasculature (careful, not to dx as ?)
• can tape BB or other metal object and reshoot film?
compare both sides
infiltrate
?
Exposure
Overexposure
• Image is white or dark ?
• Easy to see:
• Cannot see:
Overexposure
• Image is dark
• Easy to see: Thoracic spine, clavicles, behind the heart, NG & ET tube placement
• Cannot see: pulmonary vessels in the periphery, small nodules, or fine structures
Exposure
Underexposure
• Image is white or dark ?
• Easy to see:
• Cannot see:
Underexposure
• Image is white
• Easy to see: pulmonary vasculature (don’t mistake for infiltrate)
• Cannot see: behind the heart, spinal anatomy, or behind hemidiaphragms
Know the major landmarks: Slides 27-30!
Know the major landmarks: Slides 27-30!
Silhouette Sign
• very useful in interpreting a CXR
• it helps to determine the location of an abnormality in relation to ?
• RML vs RLL (pneumonias, masses)
- loss of right heart border indicates that the infiltrate is in the ?
- loss of right hemidiaphragm indicates that the infiltrate is in the ?
- loss of left hearth border indicates that the infiltrate is in the ?
- loss of left hemidiaphragm indicates that the infiltrate is in the ?
Silhouette Sign
• very useful in interpreting a CXR
• it helps to determine the location of an abnormality in relation to normal structures
• RML vs RLL (pneumonias, masses)
- loss of right heart border indicates that the infiltrate is in the RML
- loss of right hemidiaphragm indicates that the infiltrate is in the RLL
- loss of left hearth border indicates that the infiltrate is in the lingula of the LUL
- loss of left hemidiaphragm indicates that the infiltrate is in the LLL
Aspiration pneumonia
Aspiration:
CXR usually performed immediately after ?
F/U should be performed w/in X hrs ?
Aspiration pneumonia
Aspiration: the inhalation of gastric contents
*following seizure, cardiac resuscitation, anesthesia related complication
CXR usually performed immediately after incidence
F/U should be performed w/in 12 hrs
* may take several hours for the gastric contents to react with the lung to cause fluid exudate and an alveolar infiltrate
Mediastinal mass → ?
Anterior:
Mediastinal mass → widening or bulge in the central soft tissue of the chest
Anterior: thymoma thyroid lesions teratoma T cell lymphoma *The 4 Ts*
