Every earlier MRI encoding row fixed the gyromagnetic ratio and scanned base field or gradient; this scan holds those fixed and scans the ratio itself. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Every earlier MRI row fixed the gyromagnetic ratio at four
Chapters one and six both kept the gyromagnetic ratio at 4 hertz per tesla and only ever varied base field or gradient. Here base field stays 1 tesla and gradient stays 1 tesla per metre, but the ratio itself drops to 2, giving frequencies 2, 4, 6 hertz at positions 0, 1, 2 metres.
f=2(Bbase+Gx)=2,4,6
The gyromagnetic ratio rescales the whole frequency ladder
Base field and gradient never change across these rows. The gyromagnetic ratio alone stretches or compresses the three checked frequencies together.
f0=γ⋅1,f1=γ⋅2,f2=γ⋅3
A higher gyromagnetic ratio spreads the addresses further
At ratio 6 hertz per tesla, the same three fields 1, 2, 3 tesla give frequencies 6, 12, 18 hertz.