Radiology I - Chest Flashcards
CXR indications
To evaluate suspected abnormalities of heart & lungs
- Chest pain
- SOB
- Cough
- Hemoptysis
- Traumatic injury
- Postive TB test
Advantages of CXR
- Excellent eval of heart & lungs
- Quick & cheap
- Low radiation dose
Disadvantages of CXR
- Does use radiation
- Challenging in large, uncooperative pts
- Interpretation requires experience
U/s
Sound waves sent out by a probe, bounce back, creating an image on a monitor
CT scan
X-ray radiation sent out in a 3D fashion & reconstructed by a computer into 3D images
MRI
- Magnetic fields & radio frequency emissions combine to create 3D images
- Usually 2-3 planes
Nuclear medicine
Broad range of tests - injecting radioactive isotopes into the body & then imaging this
Black areas on CXR
More radiation passes through
White areas on CXR
More radiation absorbed
X-ray densities
From least to most dense:
- Air/lung
- Fat
- Soft tissue density
- Bone/calcification
- Metal
Pulmonary TB
- Asymptomatic carriers
- Difficult & long tx
- Developing resistance
Primary TB infection
- Can be clinically silent
- Or can look like pneumonia w/ pleural effusion (nonspecific appearance)
Post-primary TB
- Aka. reactivation or secondary
- May develop lung cavities in upper lungs
- Often re-ignites due to relative immunocompromised
Most common etiologies of lung cavity
- TB
- Valley Fever
- Cancer (esp. squamous cell)
- Inflammatory conditions (Wegener’s Disease)
Atelectasis
- Lung collapse
- Difficult to distinguish from pneumonia
- Long term chronic atelectasis = lung scarring
Intrinsic causes of atelectasis
- Mucous
- Foreign body
- Poor inspiratory effect, hypoventilation
- Lack of surfactant
Extrinsic causes of atelectasis
- Compressing mass
- Compressing adenopathy
- Misplaced ET tube
Pleural effusion
Accumulation of fluid in pleural space
- Lateral radiograph has higher sensitivity than frontal
Pleural space
Potential space btwn lung & chest wall
Pleural effusion ddx
- Transudate
- Exudate
- Air
- Blood
- Infection/pus
- Tumor
- Chronic scarring
Pleural plaques
- Soft tissue thickening & calcification
- Can be related to asbestos
Pneumothorax
Accumulation of air in pleural space
Tension pneumothorax
- Emergency
- Imminent risk of cardiopulmonary collapse
- Tx: Needle thoracotomy at 2nd rib space, mid-clavicular line
Pulmonary edema
- Movement of fluid from pulmonary venous system into lungs
- Exists on a spectrum from pulmonary venous HTN (lower pressures) to frank pulmonary edema (higher pressures)
Pulmonary edema
- Movement of fluid from pulmonary venous system into lungs
- Exists on a spectrum from pulmonary venous HTN (lower pressures) to frank pulmonary edema (higher pressures)
Stages of CHF
- Cardiomegaly
- Pulmonary venous HTN
- Pulmonary interstitial edema
- Pulmonary alveolar edema
PA chest (pathway)
x-ray source –> posterior –> anterior –> detector
- Heart shadow is smaller
- < 50% of thoracic width
AP chest (pathway)
x-ray source –> anterior –> posterior –> detector
- < 55-60% of thoracic width
Calcified pulmonary nodule
- Benign, no further f/u
- Calcified nodule = granuloma
Non-calcified pulmonary nodule
- < 3cm = nodule
- > or = 3cm = mass
- Large nodule > 0.8cm or growing –> biopsy &/or PET/CT
Chest trauma
- CXR are insensitive to rib fractures
- RIB FILMS are done to evaluate rib fractures
Lines & tubes
- CXRs are commonly used to confirm line placement
Chest CT advantages
- Excellent eval of most structures of chest
- Fast
Chest CT disadvantages
- Higher radiation dose
- Cost
Cause of cardiogenic pulmonary edema (true CHF)
- Increased hydrostatic pressure at the pulmonary capillary level
- Water is forced from high to low pressure
Cause of non-cardiogenic pulmonary edema
- Increased permeability at the pulmonary capillary level
- Water is able to leak out
- Look identical to true CHF on radiograph
