Xrays Flashcards
What is the rule of thumb of number of ribs and viability of the x ray?
If diaphragm lies below ninth rib it’s okay
What are the nine steps to reading a chest radiograph?
Check ID of patient Observe general symmetry Focus on lung fields Focus on mediastinum Focus on diaphragm/costophrenic angles Focus outside chest Focus on ribs and chest wall Look in sneaky places - lung apex and retrocardiac region Look at lateral
How can cardiomegaly be diagnosed on a chest x ray?
Cardio thoracic ratio is max heart diameter/max thoracic diameter
Normal is less than or equal to .5
What are the different borders seen on the chest x ray and which structures are they comprised of?
Left heart border - aortic knob, pulmonary artery, left atrium, LV
Right heart border - right atrium
Anterior heart border - best on lateral view, RV
Posterior heart border - best on lateral, left atrium
How is the azygous vein seen on x rays?
In angle between trachea and right main stem bronchus
Not seen on PA unless pathologically enlarged
At same level as aortic knob
Dilated indicates RHF, tamponade or other circulatory abnormality
What are the areas of normal asymmetry on the chest x ray?
Left hills higher than right - fingertip rule
Right hemidiaphragm higher than the left
When is an apical lordotic view x ray indicated?
Used to provide unobstructed view of lung apices
Looks between rather than through anterior ribs
AP projection made with patient or beam tiles so it passes parallel to long axis of ribs and through gap between them
Patient is standing and leaning back
What structures can be seen in the retro cardiac space?
Descending aorta
Spine
Pulmonary vessels
What regions are seen best on a lateral x ray?
Posterior costophrenic angle Retro cardiac region Retro sternal region Anterior and posterior contours of heart Spine Sternum
Where will pleural effusions appear?
Dependent areas
With patient upright, posterior costophrenic angle on lateral view then costophrenic angle on frontal view
What are the findings of a solitary pulmonary nodule?
Most often from primary bronchogenic carcinoma
Can also be from inf, metastasis, laceration, infarct, AVM, inflammatory
Pulm location - surrounded on all sides by lung or forms acute angles where it touches chest wall
What is the Ddx of multiple pulm nodules found on x ray?
Metastases most common
Then inf including septic emboli, inflammatory disorders like rheumatoid nodules, multiple infarcts or AVMs
What are chest radiograph findings in pneumothorax?
Air will accumulate in non dependent portions
Visualization of visceral pleural line
Lack of lung markings peripheral to pleural line
Increased lucency on side of pneumothorax
Collapsed lung
More apparent on expiratory films
Tension PTX has inverted diaphragm and/or deviated mediastinum away
When does a tension pneumothorax become dangerous?
When it impedes venous return to the heart
What are the basics of lobar pneumonia?
Often bacterial in origin
Spread through alveoli which fill with purulent material and edema
Alveolar edema/purulence causes opacity on CXR that is shaped like pulm lobe
Air bronchograms form - opacified lung outlines air filled bronchi which remain patent
What are the findings on CXR of tb?
Upper lobe cavitary lung disease caused by caseating necrosis
Military pattern - tiny sharply defined nodules
What is contained in the mediastinum?
Heart
Great vessels
Esophagus
Trachea
What is the Ddx of an anterior mediastinal mass?
The 4 Ts: Thyroid masses Teratoma Thymic masses - thymoma Terrible - lymphoma
What are the radiographic findings of an anterior mediastinal mass?
Alteration of normal mediastinal contour on frontal view
Anterior to trachea on lateral view
May bow trachea posteriorly
Fills retro sternal clear space on lateral view
What are the radiographic findings in CHF?
Cardiomegaly
Cephalization (prominence) of upper lobe vessels
Prominent hilar vessels with indistinct margins
Interstitial edema
Kerley b lines (thick inter lobular septae)
Alveolar edema
Sometimes pleural effusion
What are four common causes of pleural effusions?
Pneumonia
Tumors
CHF
Pulmonary emboli
What is a loculated pleural effusion?
Non free flowing
Doesn’t move as the patient moves
What is the systemic approach to reading musculoskeletal radiographs?
Check the bone - alignment, periosteum (should be invisible), cortex (should be traceable and uniform all the way around), cancellous bone
Check the joint - alignment, joint space
Check the soft tissue - edema, effusions
What is a complete vs. incomplete fracture?
Complete is cortex to cortex
Incomplete more common in children
What is a simple vs. comminuted fracture?
Comminuted fracture produces 3 or more separate fragments of bone
Simple produces only 2
What is a closed vs. open fracture?
If hematoma communicates with outside world, it is open
Gas tracking down to fracture also means open
What is an impacted fracture?
Fragments are driven together
Contrast to overriding where they lie side by side
What is a Colles fracture?
Common fracture of wrist
Distal radius
Cortical disruption in metadiaphysis with mild impaction
Mild dorsal displacement and angulation of fracture fragment
What are compression fractures?
Loss of height of anterior part of vertebral body
What is a burst fracture?
Loss of both anterior and posterior vertebral body height
More ominous than compression fracture
Potential retropulsion of fragments into spinal canal
What are radiographic features of degenerative joint disease?
Joint space narrowing and irregularity Sclerosis - whiter denser bone Osteophytes - new bone at joint margin Subchondral cyst like changes (dark holes) "Loose bodies" Joint effusion
What are radiographic features of RA?
Erosions at edges of joints Joint space narrowing Peri articular osteopenia - lucency Less osteophytes or sclerosis than DJD Subluxations Ankylosis can occur
What are radiographic features of psoriatic arthritis?
Soft tissue swelling
New bone formation
Dramatic joint space destruction
Pencil in cup erosions
What are the radiographic features of osteomyelitis?
Loss of cortex
Gas bubbles
Lucent areas with loss of trabeculae
What are radiographic features of multiple myeloma?
Classically punched out lytic lesions in the skull
Well defined but non sclerotic margins
Which metastases are typically osteoblastic as opposed to lytic?
Breast
Prostate
What are the radiographic features of osteosarcoma?
Permeating cortical destruction
Soft tissue mass
Tumor new bone formation
Periosteal reaction
