How Can we Overcome Limits to Spatial Resolution?
Use high resolution pulse sequences.
- interleaved EPI: 256x256 pixels, but poor temporal resolution (8 to 16 TR periods)
Use the “Fast Response” dip in signal to more accurately localise to neuronal bed?
- still debate as to its existence in fMRI
- at least a factor of 3 smaller in magnitude than the more commonly used positive BOLD response
Use spin echo versus gradient echo sequences
- but, sensitivity is considerably reduced (factor of 5 or more)