Radiology Quiz

1. Density

-air (black)

-fat (dark gray)

-fluid/soft tissue (light gray)

-calcium/bone (Nearly white)

-metal (white)

2. thickness

-the thicker it is, the brighter it appears

3. duration of exposure

-short=too bright

-long=too dark

what are some factors that determine shadow brighteness on an XR?

-uses two XR beams in quick succession (one at high energy and one at low) to produce images

-images are processed and create a soft tissue only and bone only image

What is a dual energy chest XR

-composed of thousands of tiny sqaures called pixels

-creats cross sectional images by having the XR beam rotate around the patient

-a 3D image is created and the computer displays a series of 2D slices

What is computed tomography (CT)

-value of how much XR beam is absorbed by tissues at each point of the scan

the CT number (measured in HU)

-central point (midpoint) of the range of HU that are displayed.

-can be adjusted to shift the focus to different densities

CT window level

-range of HU that is displayed as shades of gray

-narrow window: enhances contrast between tissues

-wide window: broader range of densities (useful for lungs)

CT Window width

-eliminates superimposition

-better contrast

-multiple planes and 3D

-more accurate

-fast imaging

CT advantages

-higher radiation dose -uses IV contrast (allergy risk and can cause renal dysfunction)

-metal artifacts can ruin images

CT disadvantages

-evaluate symptoms and physical signs

-evaluate placement of central lines and tubes

-screening for pneumothorax after lung biopsy, central line placement and pacemaker placement

-evaluate suspected pacemaker lead fracture

-pre op clearance

When should you order an XR

-evaluation of cancer/mass

-pulmonary embolism

-trauma

-thoracic aortic aneurysm/dissection

When should you order a CT

-posteroanterior view -goes from back to front

PA view

-anteroposterior view

-beam travels front to back

-heart appears large

AP View

-pleural effusion (fluid will go to the bottom)

-pneumothorax (air will rise to top)

Lateral decubitus view is helpful in diagnosing what

-confirm pt name, DOB, and MRN

-if there is a previous XR, compare to most recent

what are the first steps to reading a CXR

-rotation: is the XR straight or at an angle?

-spine should be vertical, clavicles should be equidistant from spine

What does the R stand for in RIPE

-inspiration: we need good inspiratory effort

-should see 9-10 posterior ribs or 6-7 anterior ribs (7th piercing the diaphragm)

What does the I stand for in RIPE

-lung volumes appear falsely low

-lung markings appear falsely prominent

-cardiac silhouette and mediastinum falsely appear enlarged

consequences of inadequate inspiration

-projection: is it in AP or PA view

-most are PA (AP will be labeled)

What does the P stand for in RIPE

-exposure: can the details be seen (ex. the vertebral bodies behind the heart)

what does the E stand for in RIPE

-excess brightness: falsely prominent pulm markings

-diminished brightness: falsely diminished pulm markings

-excess or diminshed contrast: falsely diminished pulm markings (obscurs pulm nodules or pneumothoraces)

what are the consequences of inadequate exposure and penetration?

-airway: deviation, foreign body

-bones and soft tissue

-cardiac and mediastinum

-diaphragm

-edges of heart

-fields and fissures of lungs

-gastric bubble

-hila

-instruments

Systematic approach to reading a CXR (ABCDEFGHI)

-can we see the trachea and is it in midline or deviated

A: Airway

-away from one side

-large pleural effusion

-tension pneumothorax

-mass/adenopathy

Pushing of the trachea

-towards one side

-atelectasis associated with collapse of part or an entire lung

pulling of the trachea

-are there fractures

-scoliosis and kyphosis

-soft tissue emphysema

-barrel chest

B: Bone and soft tissue

-are they in the correct location and the correct size

C: cardiac silhouette and mediastinum

-dome shaped

-sharp costphrenic angles on both sides

-right diaphragm should be higher

D: diaphragm

pneumonia

what can a raised diaphragm indicate

emphysema

what can a flattened diaphragm indicate

effusion

what can blunting of the costophrenic angles indicate

-looking for silhouette sign (obscuring of the heart boarder)

E: edges of the heart

-look for symmetry, vascularity, any masses, nodules, infiltration, fluid, bronchial cuffing

F: fields of the lungs

pneumothorax

what does a lack of lung markings raises suspicion for

mesothelioma or hemothorax

Pleura is only visible when thickened or fluid accumulates. this may indicate

-should be visible below the heart

G: Gastric bubble

-look for nodes or vasculature on the hila of both lungs

-left hila should be higher

H: Hila

-TB or sarcoidosis

What does bilateral hilar enlargment suggest

cancer

What does unilateral hilar enlargment suggest

-look for tubes, IV lines, EKG leads, pacemarkers, surgical drain, prosthetic valve replacement, etc

I: instruments

-affected lung becomes more opaque (b/c its a loss of volume in the lung)

-interlobar fissure shifts towards the area of atelectasis

-MC cause: post operative state

Atelectasis

-subsegmental (linear densities usually parallel to diaphragm at lung bases)

-compressive (effusion, pneumothorax, lesion)

-obstructive (resorption of air from alveoli, distal to obstruction)

What are the 3 types of atelectasis

-MC at lung base, posteromedially and must be subpleural

-consequence of chronic pleural scarring (Asbestos, TB)

-will see rounded densitiy at lung bse, comet tail, and crow's feet

round atelectasis on a CT

-Trasudative: CHF, hypoalbumneimia, cirrhosis, nephrotic syndrome

-exudative: CANCER, empyema, hemothorax, chylothorax

Types of pleural effusions

-blunts costophrenic angles

-haze over entire hemithorax (densest at base)

Pleural effusion on an XR

-air bronchograms

visible airways inside a consolidated lung.

Pneumococcal Pneumonia appearance

-obscured the left heart border and diaphragm

Lingular pneumonia appearance

-hazzy (whiteness) over the effected area

Lobar pneumonia appearance

-patches of airspaces in parts of both lungs

Segmental pneumonia (bronchopneumonia) appearance

-Bilateral, central disease that is primarily reticular in nature

interstitial pneumonia (PCP) appearance

-diffuse patchy inflammation in interstitial areas of alveolar walls (concentrated in perihilar area)

Walking pneumonia appearance

-density that is rounded

Round pneumonia appearance

-bilateral airspaces

-lucencies represetning cavities

cavitary pneumonia appearance

-bilateral airspace disease in the lower lobes

aspiration pneumonia appearance

-may be normal

-may have unilateral or patchy b/l areas of consolidation, opacities, bronchial wall thickening, and small pleural effusions

Viral pneumonia and bronchitis imaging

peribronchial thickening (cuffing)

What is found in kids with a viral infection (pneumonia)

-may see consolidations, ground glass opacities, or nodules

-MC in peripheral and lower zone

-MC bilaterally

Covid on CXR

-must see visceral pleural line (expiration image is easier to see it on)

Pneumothorax appearance

-no heart or trachea shift

-subcutaneous emphysema is seen

simple pneumothorax appearance

-mediastinal and trachea shift

-almost total collapse of lung

-left diaphragm depressed

Tension pneumothorax appearance

-pneumothorax on supine radiograph

-costophrenic sulcus will appear lower on one side

Deep sulcus sign meaning

-stringy densities (air in neck)

-air around the heart

Pneumomediastinum appearance

very thick white line on the subcutaneous area

subcutaneous emphysema appearance

-substernal thyroid mass

-lymphoma

-thymoma

-teratoma

differential diagnosis for anterior mediastinum

lymphadenopathy can produce masses

what is commonly seen in the middle mediastinum

home of tumors of neural origin

posterior mediastinum diagnosis

mass is over 3cm

what is the difference between a nodule and a mass?

"Hot" it appears yellow

How does cancer appear on a PET scan

-atypical soft tissue mass in upper lobe of lung

-can see rib destruction or SVC obstruction

Pancost tumor appearance

white mass in hilar area

Hilar adenopathy appearance

normal!

How do most pulmonary embolism area on an XR

hamptons hump

What could be seen in an XR of a PE

-embolus fills both pulmonary arteries (left side)

-right picture is a small embolus

How does a saddle embolus appear

hyperinflation and flattening of the diaphragm

How does COPD appear on an XR

-very small, blister like lesion on visceral pleura normally at apex

-can't be seen on XR, very thin walled

Blebs on an CT

-bigger than 1cm, associated with emphysema

-seen as localized paucity of lung markings

-thin wall (<1mm)

-seen better with CT than XR

Bullae appearance

-in lung parenchyma or mediastinum

-thicker than bulla (<3mm)

cysts appearance

-thickest wall of the lesions (3mm-several cm)

-need to confirm with CT

-bronchogenic carcinoma, TB, lung abscess

Cavities appearance

-parallel line opacities (tram tracks)

-signet ring signs

-thickened walls of dilated bronchi

-cystic lesions

bronchiectasis appearance

enlarged heart

cardiomegaly appearance

seen in pulmonary edema

Kerley B lines

-fluid accumulates and the bronchial waller becomes thicker and appearance ring like

Peribronchial cuffing on XR

-kerley lines

-pleural effusion

-peribronchial cuffing

-hydrostatic intersitital edema

CHF on a chest XR

-b/l perihilar airspace disease with diffuse interstitial markings

-kerley B lines

(PICTURE ON LEFT)

Pulmonary edema appearance

-thoracic aorta is enlarged

thoracic aortic aneurysm appearance on XR

thoacic aortic aneurysm appearance on CT

-widened mediastin and pleural effusion

thoracic aortic dissection

-3-5cm above carina

-middle of carina and clavicles

ET tube

-tip halfway between stoma and carina (T3 level)

Tracheostomy tube

-tip in SVC

Central venous catheter

-tip in SVC

-hard to see

peripherally inserted central catheters

-2cm from hilum in proximal pulmonary artery

swan ganz catheter

-effusion: tip posteriorly and inferiorly

-pneumothorax: tip anteriorly and superiorly

Chest tube

tube should extend about 10cm

Nasogastric tube (NGT)

-tip should be in 2nd or 3rd portion of duodenum

dobhoff tube (DHT)

-free air under diaphragm

Perforated bowl appearance

PA View

Lateral view

AP View

lateral decubitus view

epidural hematoma