There isn't any difference in the Fourier analysis between spectroscopy and imaging. In imaging you're just encoding position as a frequency and if you enforce Cartesian sampling the analysis remains the same, including combining extra dimensions. Spectroscopy and flow imaging experiments can get pretty crazy with 5-6 encoding dimensions limited only by your patience and instrument drift over longer periods (weeks).
The differences between spectroscopy and MRI are primarily application driven and then because it is tricker to apply precise magnetic field gradient pulses vs precisely timing RF pulses. Combined with the fact people are a lot bigger, more impatient and more delicate than test tubes while imaging can also be far less quantitative drives the design of very different NMR/MRI pulse sequences. In imaging, the speed gains and human placed limits on gradient slew rates (Audio frequency dB/dt induces currents in neurons) often justify the trouble of non-Cartesian and/or incomplete sampling.
If you want a next step for MRI signal processing, look into multiple-coil reconstruction techniques and how they not only combine the spacial sensitivity profiles of the coils with gradient imaging, without knowing the actual sensitivity profiles a-priori. Pretty much every medical MRI machine uses multiple receive coils to reduce imaging times.
Note: My user name is proton gamma though I left the field mid-career to do sw development. (A far better career though not as exciting if you love physics like I do.)
(edits: grammar, probably still missed a few typos)