miscellaneous slide

 

 

 

 

 

 

 

 

 

 

Twinkle, Twinkle, T2*

This parody (written by Greg Crowther) is sung to the tune of "The Star" (written by Ann and Jane Taylor).


Lyrics

Twinkle, twinkle, T2*;
How I wonder what you are!
XY signal soon decays;
Why do the spins go out of phase?
Twinkle, twinkle, T2*;
Something pulls those spins apart.

Spin-spin crosstalk sets T2,
But by then T2* is through.
A brief duration here is sealed
By an inhomogeneous field.
Twinkle, twinkle, T2*;
Now I know just what you are!


Comments

A concise explanation of T2* -- pronounced "tee two star" -- the time constant for the decay of a magnetic resonance signal in the XY plane. As indicated above, T2* is a function of (1) random spin-spin interactions (which govern T2) and (2) inhomogeneities in the magnetic field (which keep T2* shorter than T2). This song was written for the May 2002 meeting of the International Society for Magnetic Resonance in Medicine. Ideally, it should be sung in a "round" as a demonstration of dephasing.