A .极低场MRI的磁场强度≤0.04T
B .低场MRI的磁场强度0.1~0.38T
C .中场MRI的磁场强度0.3~1.0T
D .高场MRI的磁场强度范围≥1.5T
E .高场MRI的磁场强度范围≥2.0T