This homework primarily deals with MRI imaging sequences. Notably, we will examine (a) the family of fast gradient recalled echo (GRE) sequences and (b) the echo planar imaging (EPI) sequence. For the GRE sequence, choose one representative sequence that has a fast acquisition time. For the two sequences (a) and (b), provide a brief narrative or answer for each of the following questions:

1. What is the main use for your sequence, and when would it be applied clinically?
2. What is the key difference to the spin-echo sequence?
3. Draw the timing diagram, including all RF pulses and gradients. Explain in detail the purpose of the gradients.
4. What information does the signal carry (such as T1 or T2)? Provide an explanation why.

Imporant hint: Many sequences can be found on the Web, but some contain mistakes. If you use web sources, make sure that you double-check your information.

Due date and turnin

Homework is due on 10-13-2011.

The turnin may either be a typewritten printed paper or a file sent by e-mail. If you decide to send an e-mail, you MUST use the word "HOMEWORK" in capital letters in the subject line. Otherwise I won't guarantee that I received your homework. Electronic submissions should have a single attachment with the concise report, which contains all explanations, equations, and figures. Also note that I will grade electronic submissions on-screen. Only typewritten and printed turnins can be returned to you with comments.

Maximum score is 15 points, 3 points for #1, 2 points for #2, 5 points for #3, and 5 popints for #4.
BONUS POINTS: If you provide a high-quality svg diagram (similar to Figure 18 of the MRI handout) that I can integrate in my handout, you obtain +5 bonus points. Ideally, use Inkscape to draw the diagram. You may use my spin-echo diagram and move elements (text, arrows) around as needed. Download here.

Late turnin penalty: For each late day, you lose 1 point from your total score.

Early turnin bonus: If your homework is done before the due date, you may present your work for a brief evaluation. If I find significant errors, I will point those out and return the homework to you for revision. You may turn in a revised version by the due date.