Tech trends: High field


Typical whole-body MRI: Up to 1.5T

Current Danish high-field limit:
3 Tesla for human imaging (pictures: 3T@Hvidovre)

Efforts to go higher (7T, 9T). Challenges:
Expensive equipment and siting is problematic
Relaxation times are less favorable
shorter T2s, longer T1s
RF field inhomogeneity increases
wavelength below body dimensions gives travelling waves
Remedy: Multiple receive and transmit channels/coils.
B0 field inhomogeneity increases
Remedy: Faster imaging, dynamic shimming
Mechanical forces increase
List continues: Safety, acoustic noise, gradient linearity, shifts,,..