Color Flow And Doppler Flashcards
Doppler Physics
Frequency shifted ____ by approaching target.
Up
Doppler Physics
Frequency shifted ____ by receding target.
Down
Is the degree of frequency shift proportional to velocity?
Yes
What are the modes of Doppler signal processing and display?
(Three)
- Doppler frequency spectrum
- Color flow
- Power mode
What is the Doppler Effect?
The apparent change in the frequency of a wave caused by relative motion between the source of the wave and the observer.
What color is the Doppler when moving towards the target?
Blue
What color is the Doppler when moving away from the target?
Red
What are the two main uses of Doppler in thyroid ultrasonography?
- Vascular (imaging and flow analysis of blood vessels)
- Vascularity of tissue
Doppler can be used to see vascularity of tissue to determine what four things?
- Probability of Malignancy
- Graves’ vs Thyroiditis
- Amiodarone Thyrotoxicosis
- Image Clarification
Spectral Doppler
What are the three types of velocities used for calculations?
- Peak systolic velocity
- End diastolic velocity
- Mean velocity
Resistive Index = …
(Peak systolic velocity - end diastolic velocity) / peak systolic velocity
Pulsatility Index = …
(Peak systolic velocity - End diastolic velocity) / Mean velocity
What color is the power Doppler setting?
Different shades of red
What kind of information does color Doppler provide?
Provides information regarding direction and velocity.
What kind of studies is color Doppler more useful in?
Vascular studies
Does power Doppler give any information regarding velocity?
No
Does power Doppler have more or less angle dependence compared to color Doppler?
Less angle dependence
Does power Doppler have more or less noise compared to color Doppler?
Less noise
Does power Doppler have increased or decreased sensitivity for detection of flow compared to color Doppler?
Increased sensitivity for detection of flow.
Name one issue with Doppler usage?
User variability
How many grades are there on the Doppler grading scale?
4
Grading Scale:
1
Absent vascularity
rare with modern equipment
Grading Scale:
2
Mostly peripheral vascularity
Grading Scale:
3
Peripheral greater than intranodular
Grading Scale:
4
Predominantly intranodular
Approximately what percentage of cancers have an intra-nodular vascular pattern?
74%
When is ultrasound guided fine needle aspiration recommended based on risk factors?
If independent risk factors are present.
What is recommended if no high risk features are present on ultrasound examination?
Follow-up with clinical and ultrasound evaluation.
Which has a better negative predictive value when predicting malignancy?
Power Doppler or color Doppler…?
Power Doppler
What is more frequently seen in malignant nodules…
Vascularity or no vascularity?
No vascularity
Benign or malignant?
Taller than wide?
Malignant
Which type of thyroid cancer may power Doppler be predictive of?
Follicular cancer
Dense fibrosis is seen in ______ % of papillary carcinoma.
56 - 89%
Which type of blood flow is the only ultrasound feature predictive of cancer (follicular)?
Internal blood flow
Is there any significant correlation between the color Doppler pattern and the malignancy rate of solid round isoechoic nodules?
No significant correlation
What is the most important variable (on ultrasound) significantly associated with follicular neoplasms?
Irregular margins
Is the negative predictive value of Doppler sufficient to obliterate the need for FNA biopsy?
No
Which has greater sensitivity and is able to detect lower degrees of internal flow…
Color Doppler or Power Doppler?
Power Doppler
What is type 1 amiodarone-induced thyrotoxicosis?
Graves’ disease like hyperthyroidism - in patients with pre-existing thyroid abnormality.
How is type 1 amiodarone-induced thyrotoxicosis treated?
Thionamides and perchlorate.
Type 1 amiodarone-induced thyrotoxicosis…
Vascularity?
Normal or increased vascularity
What is type 2 amiodarone-induced thyrotoxicosis?
Destructive thyroiditis-like thyrotoxicosis
Type 2 amiodarone-induced thyrotoxicosis…
Vascularity?
Absent vascularity
How is type 2 amiodarone-induced thyrotoxicosis treated?
Glucocorticoids
Which interleukin is often elevated in type 2 amiodarone-induced thyrotoxicosis?
Interleukin 6
Does type 1 or type 2 amiodarone-induced thyrotoxicosis cause elevated interleukin 6?
Type 2 amiodarone-induced thyrotoxicosis
Amiodarone-induced thyrotoxicosis.
Is the response rate to prednisone better when color Doppler flow is absent or present?
Absent
Amiodarone-induced thyrotoxicosis.
What should you treat the patient with when color Doppler flow is absent?
Prednisolone
Amiodarone-induced thyrotoxicosis.
What should you treat the patient with when color Doppler flow is present?
Thionomides and perchlorate.
Amiodarone-induced thyrotoxicosis.
What should you treat the patient with if they are unresponsive to your initial treatment?
Combination therapy / surgery
When an interface is moving with respect to the reflected sound wave, the frequency of the reflected sound is altered.
True or false?
True
What is the peak systolic velocity in ‘thyroid inferno’?
8 - 20 cm/sec
What is the peak systolic velocity in ‘thyrotoxicosis factitia’?
3 - 5 cm/sec
What is ‘thyrotoxicosis factitia’?
Minimal intrathyroidal vascular flow in thyrotoxicosis
Destructive thyroiditis usually has low vascularity.
True or false?
True
What is the ‘gold standard’ to diagnose the etiology of thyrotoxicosis?
Radioactive iodine uptake
In normal nodes where do vessels enter?
Centrally at the hilus
In normal nodes, which axis do vessels spread along?
The long axis
Where do vessels enter malignant nodes?
Enter peripherally in the node capsule.
Benign or malignant?
Increased or disordered vascularity seen peripherally and centrally in the lymph node.
Malignant
Which two settings increase sensitivity for detection of low flow (when doing Doppler of nodes)?
- Low wall filter
- Low pulse repetition frequency
Which glands have polar arteries?
Parathyroid glands
Does lack of flow in a follicular lesion make malignancy more or less likely?
Less likely
Is vascularity relevant in lesions suspicious for papillary thyroid carcinoma?
No
