18 Introduction to Chest Radiology 1 (2) Flashcards
1
Q
Normal chest radiograph
- Components
- Search pattern
- Concept
A
- Components
- Standard views
- Radiographic densities
- Film exposure
- Chest CT
- Search pattern
- Heart
- Mediastinum
- Lungs
- Chest wall
- Concept
- Place area of interest next to cassette

2
Q
Standard radiographic views
A
- Postero-anterior (PA)
- Antero-posterior (AP)
- Left lateral CXR

3
Q
Postero-anterior (PA) CXR
A
- X-ray traverses posterior to anterior
- Heart next to cassette
- Patient is upright
- 6 feet from X-ray tube
- Decrease image magnification
- Increase sharpness
- Full inspiration

4
Q
Antero-posterior (AP) CXR
A
- X-ray traverses anterior to posterior
- Patient upright, supine
- Spine next to cassette
- 3 feet from x-ray tube
- Increase image magnification
- Decrease sharpness
- PA is preferred

5
Q
Left Lateral CXR
A
- X-ray traverses R –> L
- Left side next to film
- Heart & aorta on left
- Decrease magnification
- Evaluate behind heart
- Summation of lungs

6
Q
5 radoigraphic densities
- 5 radiographic densities
- Anatomic structures differ in density
A
- 5 radiographic densities
- Air - lungs, trachea
- Fat
- Soft tissue - fat, blood, muscle
- Bone - calcium
- Metal - hardware, contrast
- Anatomic structures differ in density
- Low density material (air) represented as black
- Dense material (bone, metal) represented as white
- Body tissues are varying degrees of grey

7
Q
Image exposure
- Unexposed X-ray film
- Anatomic structures differ in density
- Dense tissue
A
- Unexposed X-ray film starts off as white
- When radiated, the silver ion (black) in x-ray film emulsion precipitates
- The more radiation that X-ray film receives, the blacker it becomes
- Anatomic structures differ in density
- Attenuation of X-rays depends on density and thickness of tissues
- X-ray image is a map of X-ray attenuation
- Dense tissue (bone) blocks more radiation from reaching the film
- Air – black
- Soft tissue – grey
- Bone – white

8
Q
Computed axial tomography (CT)
A
- Cross-sectional imaging
- Computer processing and reconstruction
- Superior tissue contrast, anatomic localization
- Bread-slicer, view from feet
- Helical multi-detector technique
- High radiation dose

9
Q
Computed axial tomography (CT)
- Helical multi-slice CT acquisition
- Multi-detecter helical CT
- High resolution chest CT (HRCT)
A
- Helical multi-slice CT acquisition
- Interpolated data from 4 detector rows
- 4, 16, 64, 128, –> 320 MDCT
- UPMC: 64 MDCT is the work horse
- Multi-detecter helical CT
- Scout image
- Breathe in
- Hold it (~20s)
- Breathe
- High resolution chest CT (HRCT)

10
Q
MDCT: axial data set
A
- Stack of images
- Axial plane
- 300 - 500 images
- 0.63 mm thin

11
Q
CT contrast bolus timing
A
- Start IV contrast before the CT
- Scan continuously at one level

12
Q
Shortness of breath
A
- Pulmonary emboli
- Venous blood clots travel to lung

13
Q
Radiation dose
A
- PA & lateral CXR
- 20 mrem = 0.2 mSv
- ~10 days natural background radiation
- Chest CT
- Equivalent to 400 CXR
- 3-5 rad = 5 mSv
- ~ 2 years background radiation
- 1 mSv = 5+ cancers per 100,000 individuals
14
Q
Search pattern
A
- Heart
- Mediastinum
- Lungs
- Pleura
- Hila
- Trachea & bronchi
- Pulmonary arteries
- Pulmonary veins
- Chest wall

15
Q
The heart
- Location
- 2 parallel pumps
- Heart size
- Heart borders
- Right
- Left
A
- Left of midline
- 2 parallel pumps
- Right
- Low pressure
- Deoxy blood to lung
- Left
- High pressure
- O2 blood to body
- Right
- Heart size: < half diameter of thorax
- Post-partum cardiomyopathy: heart is too big
- Heart borders
- Right
- SVC & RA
- Left
- Aortic arch
- Main pulmonary artery
- Left ventricle
- (Left atrial appendage)
- Right

16
Q
The mediastinum
- General
- Consists of…
- Problems
A
- General
- Central compartment
- Potential space
- Lined by parietal pleura
- Consists of…
- Heart, aorta, vessels
- Thymus
- Esophagus & trachea
- Lymph nodes
- Problems
- Encapsulated thymoma
- Mediastinal mass: lymphoma
- Neurofibroma

17
Q
Esophagus
A
- Squamous cell cancer
- Adenocarcinoma
- Oral contrast ingested

18
Q
The lungs consist of…
A
- Pleura - surrounds lung
- Lung parenchyma
- Tracheo-bronchial tree
- Pulmonary arteries (PA)
- Pulmonary veins (PV)
- Hila

19
Q
Pleura
- Pleural development
- Pleura
- Parietal pleura
- Visceral pleura
- Pleural fluid / effusion
A
- Pleural development
- Pleura begins as single layer
- Lung invaginates into coelomic cavity
- Single layer of pleura folds back on itself to form 2 layered membrane
- Pleura
- Potential space
- Parietal pleura
- Lines diaphragm
- Chest wall
- Mediastinum
- Visceral pleura
- Lines the lobes
- R & L major fissures
- (R) minor fissure
- Pleural fluid / effusion
- Hemothorax
- Fluid “meniscus”

20
Q
Pleura
- Pleural gas
- Visceral pleura
- Lines…
- L major fissure
- R major & minor fissure
- R major fissure
A
- Pleural gas
- Pneumothorax
- Visceral pleura
- Lines the lobes
- L major fissure
- LUL & LLL
- R major & minor fissure
- RUL & RML
- R major fissure
- RUL - RML from RLL

21
Q
Fissures on CT
A

22
Q
Lung parenchyma
A
- Sponge, air-filled
- Clear & more lucent at bases
- No distinct markings
- Right is bigger, 3 lobes (RUL, RML, RLL)
- Left upper, lower lobes
23
Q
Consolidation
- Normal chest radiograph & CT
- (Air space) consolidation
A
- Normal chest radiograph & CT
- Lungs are clear
- (Air space) consolidation
- Too white
- Alveolar air replaced by fluid, blood, pus, tumor
- –> confluent opacity
- Obscures architecture (broncho-vascular)
- Focal, patchy, or diffuse

24
Q
Ground glass opacity
A
- Too white
- Hazy increased lung attenuation
- Broncho-vascular markings preserved
- Partial filling of alveoli, interstitial thickening, increased capillary blood flow
- “Smeared chalk”
- Edema, pneumonia

25
Q
Atelectasis
A
- Too white
- Decreased inflation
- Decreased volume
- Increased reabsorption
- Increased opacity
- “Ectasia”
- Dilation, expansion
- Aortic ectasia - mildly dilated aorta
- Bronchiectasis - bronchial dilatation
- Atelectasis
- Gr. ateles “imperfect” + ektasis “expansion”
- “Collapse” of lung, volume loss

26
Q
Lobar atelectasis
A
- RUL
- Decreased inflation of segment, lobe, or lung
- Reabsorption of air
- Involved lung has decreased volume, increased opacity
- Mucous plug, stricture, tumor, or extrinsic compression of bronchus
- Non-involved lung responds
- RML

27
Q
Interstitium
A
- Continuum of loose supporting connective tissue in lung
- Interstitial lung disease
- Tissue around airways & air spaces thicken, with preservation of alveolar air
- Pulmonary lobule
- Septa
- Arteriole
- Bronchiole
- Pulmonary edema

28
Q
Alveolar ducts and pulmonary acinus
- Microscopic anatomy
- Fibrosing alveolitis
- Reticular pattern
A
- Microscopic anatomy
- Terminal airways
- Alveolar ducts
- Acini
- Fibrosing alveolitis
- Alveolar collapse
- UIP / IPF
- Reticular pattern
- Fibrosis
- Honeycomb

29
Q
Problems
- Air trapping
- Smoker
- Renal cell carcinoma mets
- 21 yo man with cough
A
- Air trapping
- COPD
- Too black
- Smoker
- Nodule < 3 cm
- Renal cell carcinoma mets
- Mass x 3 cm
- 21 yo man with cough
- Cystic fibrosis
- Bronchiectasis

30
Q
Tracheo-bronchial tree
A
- Ao displaces trachea to right
- Trachea –> main bronchi (T5)
- Left main bronchus is longer (5cm) & lower
- Right main bronchus is shorter, more vertical
- Normal bronchioles imperceptible

31
Q
Pulmonary arteries
A
- Right PA in front of right main bronchus
- Left PA arches over left main bronchus
- Left hilum superior
- Vertically oriented
- Follow bronchi
- Problem: pulmonary hypertension

32
Q
Hila
A
- PA, PV, bronchus –> lung
- PA makes up bulk
- Left hilum higher (98%)
- Both same height (2%)
- Right hilum not normally superior to left
- Equal size & attenuation

33
Q
Normal chest imaging
A
- CXR important tool
- PA, AP, Lateral
- Radiographic densities gas, fat, water, M+
- Film exposure
- Chest CT: x-section
- Location
34
Q
Chest imaging: search pattern
- Heart
- Lungs
- Don’t normally see…
A
- Heart size
- Hilum
- Pulmonary arteries
- Vascularity
- Lungs are clear
- Don’t normally see…
- Interstitium
- Bronchioles
- Pulmonary veins
- Pleura
- Mediastinum