18 Introduction to Chest Radiology 1 (2) Flashcards
(34 cards)
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
Atelectasis
* 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
Lobar atelectasis
* 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
Interstitium
* 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
Alveolar ducts and pulmonary acinus
* Microscopic anatomy
* Fibrosing alveolitis
* Reticular pattern
* Microscopic anatomy
* Terminal airways
* Alveolar ducts
* Acini
* Fibrosing alveolitis
* Alveolar collapse
* UIP / IPF
* Reticular pattern
* Fibrosis
* Honeycomb
29
Problems
* Air trapping
* Smoker
* Renal cell carcinoma mets
* 21 yo man with cough
* 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
Tracheo-bronchial tree
* 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
Pulmonary arteries
* 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
Hila
* 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
Normal chest imaging
* CXR important tool
* PA, AP, Lateral
* Radiographic densities gas, fat, water, M+
* Film exposure
* Chest CT: x-section
* Location
34
Chest imaging: search pattern
* Heart
* Lungs
* Don't normally see...
* Heart size
* Hilum
* Pulmonary arteries
* Vascularity
* Lungs are clear
* Don’t normally see...
* Interstitium
* Bronchioles
* Pulmonary veins
* Pleura
* Mediastinum
