Targeted imaging questions B2/3 Flashcards
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Recall the densities on X-radiographs and their radioopacity
From black to white:
- air
- fat
- soft tissue
- bone (cortical bone is whiter)
- metal
How can you tell if a patient is rotated?
Distance between spinous processes and clavicular heads should be roughly equal
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What could an unexpected white blob indicate?
- infection
- collapsed lobe
- cancer
- rarities
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What does white-out of the hemi-thorax indicate?
Lung collapse or pneumonectomy
white out of angles indicates pleural effusion
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What are the eight mediastinal contours?
- aortic knuckle
- main pulmonary artery
- right heart border (RA)
- left heart border (LV)
- descending aorta - right hemidiaphragm
- left hemidiaphragm
- right paratracheal stripe
Identify the lobes of the lungs
- right: upper, middle, lower
- left: upper, lower
Note:LUL has ‘lingula’ – analogous with middle lobe of right lung
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What are the features that should be identified on a chest x-ray?
- Check rotation (spinous processes and clav. heads)
- Check position of heart (1/3 : 2/3) or cardiac position
- Check heart size (<50% widest diameter)
- Lungs– whiter? blacker?
- tubes (med tubes)
- Look for white blobs (Infection, cancer, other)
- Check the eight cardiomediastinal contours
NOTE:
* Abnormal lung is white on CXR (95% of the time)
* A collapsed lung causes a white hemithorax
- white lung can be infection, cancer, inflammation
* A pneumothorax is black, a bulla is black
* Medical tubes are white – follow them
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Give an example of an approach to reading CXR
Patient details, adequacy of exposure, any notable features, PLANE e.g. - ECG leads, pacemaker, foreign object
A - airways: clear? trachea midline?
B - bones - fractured?
C- cardiac shadow, enlarged? cardiomediastinal contours?
D- hemidiaphragms elevated? present? clear? costophrenic angles sharp/clear?
EF- equal fields. Any increased opacities or dark zones over lungs?
G- gastric bubble present
H- hilum? enlarged?
Describe this CXR
This is a normal CXR
Patient is de-identified.
May be slightly rotated to the right.
No foreign objects.
A- clear, trachea midline
B - bones intact
C- normal cardiothoracic ratio, all cardiomediastinal contours
D- normal elevation, both hemi-diaphragms clear, costophrenic angles clear
EF- both lungs clear, normal. Maybe some increased interstitial lung marks along right lung (lateral to hilum)
G- gastric bubbles visible
H- normal size. Not enlarged
n.b. assuming PA (unless otherwise stated)
https://radiopaedia.org/cases/normal-cxr
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Describe this CXR
This is a normal lateral CXR
Patient is de-identified.
No foreign objects.
A- not really relevant
B - bones intact
C- normal cardiothoracic ratio, all cardiomediastinal contours
D- normal elevation, both hemi-diaphragms clear, costophrenic angles clear.
EF- both lungs clear, normal. Maybe some increased interstitial lung marks along right lung (lateral to hilum)
G- gastric bubble visible
NB L and R hemidiaphragams
https://radiopaedia.org/cases/normal-lateral-chest-radiograph
Describe this CXR
This is an example of a small right apical PT.
It is seen as a region of darkness.
Tips to help to find pneumothoraces include:
- the lung edge
- you should not be able to see the lung edge
- if you can, the region peripherally is likely a pneumothorax
- absence of vessels
- the lung should have vessels running through it
- these are white branching structures on the x-ray
- if there are not vessels, there may be a pneumothorax
Pneumothorax (pl: pneumothoraces) describes gas within the pleural space. This may occur because of a number of reasons and may be spontaneous. Patients will not always be symptomatic and treatment will depend on the cause. Pneumothoraces may be small or very large. The larger the pneumothorax, the more likely it is to cause symptoms e.g. pleuritic chest pain and sudden onset dyspnoea
https://radiopaedia.org/articles/pneumothorax-summary-1
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Describe this CXR
Left pneumothorax, with partial collapse of left lung.
A collapsed lung causes a white hemithorax
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Describe this CXR
Trachea is deviated.
Whenever you see deviation of the trachea, ask yourself if it has been PUSHED or PULLED. Here the trachea has been PULLED to the left by the volume loss in the left upper lobe caused by localised lung fibrosis
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What’s going in this CXR?
- tracheal deviation
- bones intact
- cardiac shadow enlarged, several contours not clear: R and L heart border, descending aorta
- L hemidiaphragm not visible, L costophrenic angle not visible
- EF: left lung not visible (ectomy)
- G: possible gastric bubble
- H: shifted to left
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What’s going on in this CXR?
Pulmonary oedema
Three clear signs:
- kerley b (septal lines)
- increased alveolar markings: airspace shadowing/consolidation
- blunt costophrenic angles
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What’s going on with this CXR?
Pericardial effusion (mainly due to globular, enlarged cardiac shadow)
A- trachea misline
B- normal
C- enlarged
D- L hemidiaphragm missing, L costophrenic angles
EF- smaller L lung visible
G- few visible
H- L hilum difficult to see
Can be accompanied with other signs e.g. of heart failure or malignancy (visible as numerous nodules)
N.B. if one side of heart was noticeable larger e.g. extended R heart border- could describe as R heart strain
What’s going on in this CXR?
Consolidation in R upper lobe
Hilar enlargement
Primary TB
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What are the types of CT?
- Routine CT Chest
a. +/- contrast - “High Resolution” CT
- CT Thoracic aortogram
- CT Pulmonary angiogram
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Describe the Hounsefield scale
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Describe the pathway of IV contrast
**Upper limb vein (brachial, basilic) > axillary vein > subclavian vein > innominate vein > **superior vena cava > right atrium > right ventricle > pulmonary trunk/outflow tract > pulmonary arteries (left and right) > lung parenchyma > pulmonary veins > left atrium > left ventricle > aorta > coronary arteries >
great vessels (upper limbs, head/neck) > descending aorta > abdominal aorta and lower limbs
Describe the types of CT
Routine CT chest ± contrast: general view of chest
* Iodinated contrast (radiodense) injected via peripheral canula at cubital
fossa, then image acquired 40s later
* Different organs can enhance at different rates - can look for
pathology of different vascularity
* If vessels are bright, then contrast has been used
- Contraindications:
- Renal impairment (kidneys can’t process iodine well)
- Allergic reaction
- Iodine-sensitive cancer
- Not contraindicated in pregnancy/breast feeding
High resolution CT (HRCT): for interstitial lung disease
* Non-contrast
* Special reconstruction filter used to increase spatial resolution (applied retrospectively)
* Inspiratory, expiratory and prone imaging
* Flip the patient to confirm lung pathology (pathology persists)
CT thoracic aorta angiogram: aortic dissection and calcifications
Non-contrast CT followed by CT angiogram
* Cannot pick up small pulmonary embolus
CT pulmonary angiogram: clot in pulmonary arteries
* Strong contrast opacification of pulmonary arteries - identify co-existing pulmonary pathology
* V/Q scan in nuclear medicine also possible
* Where contrast doesn’t perfuse (i.e. darkness) suggests clot
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What are the windows visible on CT?
Soft tissue window and lung window
List the different contrast phases in CT
Typical phases (time from injection) include:
- early arterial phase
15-25 seconds post-injection
immediately post bolus tracking - late arterial phase
30-40 seconds post-injection
15-20 seconds post bolus tracking - portal venous phase
70-90 seconds post-injection
50-70 seconds post bolus tracking - nephrogenic phase
85-120 seconds post-injection
80 seconds post bolus tracking - excretory phase
5-10 minutes post-injection
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What phase is this CT in?
In outflow tract
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What phase is this CT in?
Early arterial
What phase is this CT in?
Late arterial
What phase is this CT in?
Portal venous system
What pathological feature is visible in this CT?
Consolidation
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What pathology is visible in this Ct?
PT with bronchiectasis
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What pathological finding is visible in this CT?
pleural effusion
What pathological feature is visible in this CT?
Lung cancer
- Swiss cheese appearance of lung (many black holes)
- Emphysema: absence of lung parenchyma (lung becomes more black than normal)
- Cancer tends to be a rounded ball that grows out - never completely spherical,
usually irregular in appearance (hairy-looking ball) - Bollus: complete black part of lung
- May capitate as central part of lesion outgrows blood supply, become necrotic
- Pancoast tumour: lung cancer that occurs in lung apex - first sign is invasion into
the ribs and subclavian artery region - Causes infiltration of brachial plexus = numbness/tingling in fingers
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What is visible in this CT?
Aortic dissection
* Dilated ascending thoracic aorta: very large, dilated, calcified
* Interval flap - one lumen is true lumen, one lumen is false - causes different
contrast intensity in 2 halves
* Tends to dissect backwards towards the heart - can clip off coronary arteries
or bleed into the pericardial sac and cause tamponade
* Tear in intima (inner lining of aortic wall) due to some trauma (Hx of HT)
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What is visible in this CT?
Saddle pulmonary embolus
- Clot in pulmonary artery that stops it from getting bright -
saddle appearance as it straddles the bifurcation (into L and R lobes) - Most commonly caused by DVT that gets dislodged and
goes to the heart
Describe an approach to interpreting CT scans
- patient details, adequacy, exposure
- plane (this should also be mentioned for CXR)
- type of CT e.g. routine CT +/- contrast, HRCT, CT thoracic aorta angiogram, CTPA
- anatomical region: e.g. chest
- window?
Structures e.g.
- bone
- great vessels
- lungs
- oesophagus
- trachea
my own
What pathological finding is visible in this CT?
Aortic aneurysm
- Syphillis can cause a rupture; Marfan’s, Ehlers-Danlos, HT
- Pushing on main pulmonary trunk and pulmonary artery
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List types of ultrasound probes
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What are the advantages/disadvantages of U/s, CT, MRI and Xray?
Ultrasound:
- cheap, no radiation, poor resolution
CT:
- good resolution, low radiation, not as good resolution as MRI
MRI:
- great resolution, less available, more expensive
CXR:
- good availability, affordable, poor visualisation of soft tissues
What two structures can look similar on female pelvic U/S?
Follicles and cysts - big, circular, black
What is an additional consideration for female ultrasound?
The cycle.
- follicles vs cysts
- proliferation of endometrium vs cancer and polyps
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What are some common clinical applications of pelvic U/S?
Female
Obstetrics
Pain
Oncology
Emergency – ovarian torsion
Male
Pain
Oncology
BPH/Prostatitis
Emergency – testicular torsion, epididymo-orchitis, urethral injury
What are the clinical applications of CT scan?
Diagnose muscle and bone disorders, such as bone tumors and fractures. Pinpoint the location of a tumor, infection or blood clot. Guide procedures such as surgery, biopsy and radiation therapy. Detect and monitor diseases and conditions such as cancer, heart disease, lung nodules and liver masses
ripped off mayo clinic
What are the clinical applications of CXR?
It is used to evaluate the lungs, heart and chest wall and may be used to help diagnose shortness of breath, persistent cough, fever, chest pain or injury. It also may be used to help diagnose and monitor treatment for a variety of lung conditions such as pneumonia, emphysema and cancer.
ripeed off radiology info
