Radiology Flashcards
Discuss the various X-ray views
AP/PA: Pt must be in full inspiration for best image
Lateral:Used to confirm location of structures seen on AP/PA
Supine: pleural fluid can be missed, heart appears larger
Decubitus: Assess for free vs localized fluid, used for pneumo pt that cant stand
Expiratory: For pneumohorax and air trapping
Lordotic: For view of lung apices
Discuss the various types of CT scans
Single Spiral Spiral w/ multidetector: HRCT: can miss small lesions Pulmonary CT Angiography: Used for pulmonary emboli, Aortic dissection and AA Low dose
Discuss PET scans
Provides physiologic information rather than anatomic
-Use F-18 FDG, mimics use of glucose, finds metabolically active tissue, evaluate malignant and inflamed tissue
Function of NM scan
-Used mainly to assess pulmonary embolus, was replaced by CTA but is coming back d/t less radiation; used when no antecubital site to use for contrast, or contrast allergy
V:Q scan
- perfusion study: perfusion via the deposition of microaggregates of albumin labeled isotopes , blood flow to the lung
- ventilation study: inhale xenon 133 or technetium 99 aerosol; assess ventilation in each portion of the lung
What is the gold standard for detecting pulmonary embolisms?
Pulmonary Angiography
How can you assess normal inspiration on an X-ray?
Adults should have 10 posterior ribs above the diaphrgam. If not, heart may be large or lungs will appear dense (false pathology)
What is the systematic approach to viewing?
-Large airways, hilum and mediastinum, bronchi and lungs, pleura and diaphragm , chest wall
How do the Xray rules change with infants?
- Normally supine
- Above 4th rib for hypoventilation, below 8th for hyperventilation
- -Decubitus: if inadequate inspiration, sufficient expansion is obtained in the non-dependent lung (ex: R decubitus shows better airation of L lung)
- Thymus gland is prominent
What is the normal anatomy on Xray of large airways?
- Epiglottis: tip projects just superior to hyoid; should look like pinky NOT thumb
- Aryepiglottic folds: delineate pyriform sinuses laterally
- Thyroid: wraps around trachea
- Cricoid cartilage: posterior to trachea
- Anteiror cervical tissue width = <7mm @ C2, & < 21m @ C6
Discuss pathological anatomy of large airways on Xray
- Subepiglottic tissue: critically swollen in croup
- Tonsils: enlarge posterior to mandible in tonsillitis
- Epiglottis: looks like thumb in epiglottitis
- Thyroid: trachea may be bowed w/ thyromegaly
What are some indication of diseases on Xray?
- Ludwig’s angina: cellulitis of mouth floor (edema, narrowed airway)
- “Steeple Sign”: trachea comes to a point d/t narrowing on AP projection
- Foreign body: use lateral view to confirm in esopagus
Discuss normal hilum anatomy
- L hilum is more SUPERIOR than R hilum
- L Pulmonary a. passes OVER LUL bronchus
- R Pulmonary a passes horizontally ACROSS mediastinum
- Azygos v. passes OVER RUL bronchus to join SVC
How does Acute and Chronic Bronchitis present on CXR?
Obstructive Disease
Acute: Normal or thickened bronchial walls
Chronic: Normal or thickened LARGE bronchi (tram lines or circles; prominent at bases
Discuss Bronchiecstasis
Obstructive Disease
- Chronic inflammation w/ cartilage damage
- Irreverisble dilation of bronchial tree
- Use HRCT for confirming dilated bronchi
- Tram lines or circle shadows
- Bronchi will have greater diameter than pulmonary artery
Discuss Bronchiolitis Obliterans
Occludes small airways proximal to alveoli; Occluded by constrictive fibrosis or proliferation of granulation tissue within bronchioles.
Can cause hyperlucent lung with chronic air trapping (Swyer-James)
Discuss Emphysema on CXR
- Centrolobular (proximal acinus, upper lobes); Smoking
- Panlobular (enitre acinus, lower lobes); alpha 1 antitrypsin deficiency
- Paraseptal: idiopathic
CXR: hyperinflation (Increased retrosternal space), hyperlucency of parenchyma, narrowed cardiomediastinal sillhouette
Discuss the appearance of Airspace disease
Silhouette sign: Loss of margin of normal structures d/t loss of air-fluid interface
Ground glass apperance: indicates active and treatable process via steroid
What is the apperance of Shaken Infant Syndrome?
Rib fractures, ‘corner’ and ‘bucket handle’ fractures at metaphysis of extemities
False positives: Osteogensis Imperfecta, Metaphyseal dysplasia
Discuss the various Xray views of the sinuses?
Waters: Angled AP to show maxillary sinus
AP: ethmoid sinuses
Lateral: sphenoid and mastoid air cells
Axial: confirm whats seen on other views
Distinguish Acute from Chronic Mastoiditis
Acute: fluid but still fine bony septations
Chronic: minimal/no fluid and sclerotic thickened septations
Discuss Bullae
- Air space > 1cm
- Has walls
- Associated with paraseptal emphysea
Bronchial Obliterans Organizing Pnuemonia
Restrictive disease that is not dominated by airway obstruction
Bronchiolitis obliterans IS dominated by airway obstruction
Pneumothorax on CXR
Use expiratory view and lateral decubitus
Pleural effusion on CXR
-CXR: meniscus sign – collection of fluid @ posterior costophrenic angles w/ standing pt. (lateral view)
Sinus Xray views
- Waters – angled AP to better show maxillary sinus
- AP (Caldwell) – better visualization of ethmoid sinuses w/ this view
- Lateral – best view to sphenoid sinuses & mastoid air cells
- Axial – least useful view, only used to confirm findings from other views
Mastoiditis on Xray
Normal: No fluid, filled with air
Acute: Fluid but still fine bony septations
Chronic: No fluid and sclerotic thickened bony septations
