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Phantom to test MUGA software

Phantom to test MUGA software. Bill Thomson , Joe O’Brien Nigel Williams. Not New!. Phantom developed some years ago need to test amplitude and phase component not designed for ejection fraction. Normal / Abnormal MUGA scan. Single Harmonic Fourier.

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Phantom to test MUGA software

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  1. Phantom to test MUGA software Bill Thomson , Joe O’Brien Nigel Williams

  2. Not New! Phantom developed some years ago need to test amplitude and phase component not designed for ejection fraction

  3. Normal / Abnormal MUGA scan

  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  .

  5. Sum of Cos and Sin terms + =

  6. Sum of Cos and Sin terms + =

  7. Sum of Cos and Sin terms + = • Frequency does not change • phase change only

  8. Sum of Cos and Sin terms + = • Frequency does not change • phase change only

  9. Single harmonic Fourier fit For each pixel, A Amplitude functional image extent of change  Phase functional image timing A 

  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

  11. Test Procedure • Need to input sinusoid terms • want amplitude range 0 - 100% • want phase values 0 - 360

  12. Sinusoid shape A A

  13. Sinusoid shape A A

  14. Curves generated

  15. Curves generated

  16. rotating plane phantom

  17. Amplitude and phase

  18. Amplitude and phase

  19. Phase direction note 90 degree shift in phase angle Phase should follow the phantom Phase is actually going in opposite direction

  20. Change of ED ROI

  21. Effect of change in ED position

  22. Different ROI position

  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

  24. Previous work - different processor Area of LV was delayed phase shows early contraction!! phase was reversed

  25. Previous work - different processor Area of LV was delayed phase shows early contraction!! phase was reversed Corrected program

  26. Higher Harmonic testing 1st harmonic

  27. Higher Harmonic testing 1st harmonic 2nd harmonic

  28. Higher Harmonic testing 1st harmonic 2nd harmonic 3rd harmonic

  29. 3 Harmonic phantom

  30. 3 harmonic phantom Fourier curve fit tries to fit first EF type component only

  31. 3 harmonic phantom , different ROI

  32. 3 harmonic phantom , different ROI

  33. 3 harmonic fit to noisy data

  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

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