Magnetic Resonance Spectroscopy (MRS)

Question 1

What is H binding?

Answer 1

Shielding and deshielding of electron shells

Question 2

What is J-coupling?

Answer 2

Changes in magnetic field of neighboring proton

1 peak (on spectrum) is split into 2

Question 3

Why do J-coupling splits occur?

Answer 3

The quantum state of neighting proton (up or down)

If spin up: adds to magnetic field (faster)
If spin down: subtracts from magnetic field (slower)

Question 4

What does J-coupling depend on?

Answer 4

-quantum states
-closeness of molecules
-area/size of spike = concentration

Question 5

What are the common metabolites?

Answer 5

-N-Acetyl Aspartate (NAA)
-Creatine / phosphocreatine (Cre)
-Choline (Cho)
-Lactate (Lac)

Question 6

What is NAA?

Answer 6

metabolite associated with number of neurons (ex. epilepsy)

Question 7

What is Cre?

Answer 7

metabolite associted with energy buffer in energy transportation (mitochondria)

Question 8

What is Cho?

Answer 8

metabolite associated with building up cell membranes (ex. cancer)

Question 9

What is Lac?

Answer 9

metabolite associated with anaerobic energy production (ex. cancer, hypoxia)

Question 10

What is PRESS?

Answer 10

Point RESolved Spectroscopy

selective excitation of 1H molecules

double SE sequence (90 - 180 - 180 - echo)

minimal TE

Question 11

What is a chemical shift?

Answer 11

shift in resonance (larmor) frequency