Transcript Phantom to test MUGA software Bill Thomson , Joe O’Brien Nigel Williams.
Slide 1
Phantom to test MUGA software
Bill Thomson , Joe O’Brien
Nigel Williams
Slide 2
Not New!
Phantom developed
some years ago
need to test amplitude
and phase component
not designed for
ejection fraction
Slide 3
Normal / Abnormal MUGA
scan
Slide 4
Single Harmonic Fourier
At each pixel position, we fit a curve based on first term
of Fourier series
a + b.sin(t) + c.cos(t)
= A.sin(t + )
the first harmonic is a sinusoid function with the
fundamental frequency and a phase angle .
Slide 5
Sum of Cos and Sin terms
+ =
Slide 6
Sum of Cos and Sin terms
+ =
Slide 7
Sum of Cos and Sin terms
+ =
• Frequency does not change
• phase change only
Slide 8
Sum of Cos and Sin terms
+ =
• Frequency does not change
• phase change only
Slide 9
Single harmonic Fourier fit
120
For each pixel,
100
A
80
60
A
Amplitude functional image
extent of change
40
20
0
1
5
9
13
17
21
Phase functional image
timing
Slide 10
Amplitude and Phase
Amplitude
how much movement
Phase
onset of contraction
15% threshold (from amplitude)
histogram of phase in whole image
ED L ventricle region
Slide 11
Test Procedure
Need to input sinusoid terms
want amplitude range 0 - 100%
want phase values 0 - 360
Slide 12
Sinusoid shape
A
A
Slide 13
Sinusoid shape
A
A
Slide 14
Curves generated
Slide 15
Curves generated
Slide 16
rotating
plane
phantom
Slide 17
Amplitude and phase
Slide 18
Amplitude and phase
Slide 19
Phase direction
note 90 degree shift in
phase angle
Phase should follow the
phantom
Phase is actually going in
opposite direction
Slide 20
Change of ED ROI
Slide 21
Effect of change in ED position
Slide 22
Different ROI position
Slide 23
Phantom for EF curve creation
• Perimeter of phantom based on EF curve
• similar effects seen
• shows robust Fourier fit at low ejection
fraction and counts
Slide 24
Previous work - different processor
Area of LV was delayed
phase shows early contraction!!
phase was reversed
Slide 25
Previous work - different processor
Area of LV was delayed
phase shows early contraction!!
phase was reversed
Corrected program
Slide 26
Higher Harmonic testing
1st harmonic
Slide 27
Higher Harmonic testing
1st harmonic
2nd harmonic
Slide 28
Higher Harmonic testing
1st harmonic
2nd harmonic
3rd harmonic
Slide 29
3 Harmonic phantom
Slide 30
3 harmonic phantom
Fourier curve fit tries to fit
first EF type component
only
Slide 31
3 harmonic phantom , different ROI
Slide 32
3 harmonic phantom , different ROI
Slide 33
3 harmonic fit to noisy data
Slide 34
Issues
• Phase angle appears to run in wrong direction
• Will not affect aneurism detection
• Amplitude and phase dependent on ROI
• Fourier fits to CDBS curve
• Time to Peak Fill is based on Fourier curve
• Suggest use 4 harmonic fit routinely
Phantom to test MUGA software
Bill Thomson , Joe O’Brien
Nigel Williams
Slide 2
Not New!
Phantom developed
some years ago
need to test amplitude
and phase component
not designed for
ejection fraction
Slide 3
Normal / Abnormal MUGA
scan
Slide 4
Single Harmonic Fourier
At each pixel position, we fit a curve based on first term
of Fourier series
a + b.sin(t) + c.cos(t)
= A.sin(t + )
the first harmonic is a sinusoid function with the
fundamental frequency and a phase angle .
Slide 5
Sum of Cos and Sin terms
+ =
Slide 6
Sum of Cos and Sin terms
+ =
Slide 7
Sum of Cos and Sin terms
+ =
• Frequency does not change
• phase change only
Slide 8
Sum of Cos and Sin terms
+ =
• Frequency does not change
• phase change only
Slide 9
Single harmonic Fourier fit
120
For each pixel,
100
A
80
60
A
Amplitude functional image
extent of change
40
20
0
1
5
9
13
17
21
Phase functional image
timing
Slide 10
Amplitude and Phase
Amplitude
how much movement
Phase
onset of contraction
15% threshold (from amplitude)
histogram of phase in whole image
ED L ventricle region
Slide 11
Test Procedure
Need to input sinusoid terms
want amplitude range 0 - 100%
want phase values 0 - 360
Slide 12
Sinusoid shape
A
A
Slide 13
Sinusoid shape
A
A
Slide 14
Curves generated
Slide 15
Curves generated
Slide 16
rotating
plane
phantom
Slide 17
Amplitude and phase
Slide 18
Amplitude and phase
Slide 19
Phase direction
note 90 degree shift in
phase angle
Phase should follow the
phantom
Phase is actually going in
opposite direction
Slide 20
Change of ED ROI
Slide 21
Effect of change in ED position
Slide 22
Different ROI position
Slide 23
Phantom for EF curve creation
• Perimeter of phantom based on EF curve
• similar effects seen
• shows robust Fourier fit at low ejection
fraction and counts
Slide 24
Previous work - different processor
Area of LV was delayed
phase shows early contraction!!
phase was reversed
Slide 25
Previous work - different processor
Area of LV was delayed
phase shows early contraction!!
phase was reversed
Corrected program
Slide 26
Higher Harmonic testing
1st harmonic
Slide 27
Higher Harmonic testing
1st harmonic
2nd harmonic
Slide 28
Higher Harmonic testing
1st harmonic
2nd harmonic
3rd harmonic
Slide 29
3 Harmonic phantom
Slide 30
3 harmonic phantom
Fourier curve fit tries to fit
first EF type component
only
Slide 31
3 harmonic phantom , different ROI
Slide 32
3 harmonic phantom , different ROI
Slide 33
3 harmonic fit to noisy data
Slide 34
Issues
• Phase angle appears to run in wrong direction
• Will not affect aneurism detection
• Amplitude and phase dependent on ROI
• Fourier fits to CDBS curve
• Time to Peak Fill is based on Fourier curve
• Suggest use 4 harmonic fit routinely