An axial MR slice at the isocentre of a 1.5 T scanner has thickness 2.5 mm. Slice-selection gradient is 2 gauss/cm and proton gyromagnetic ratio is 42.58 MHz/T. Find RF bandwidth in kHz.
Slice bandwidth is Δf=(γ/2π)GΔz when the supplied ratio is in Hz/T. Convert gradient: 2 gauss/cm=.02 T/m. Field variation over .0025 m is .00005 T. Thus Δf=42.58×10⁶×.00005=2129 Hz=2.129 kHz, or 2.13, B. The main static field sets centre frequency, not this bandwidth.
More Magnetic Resonance Imaging questions
GATE 2020 BM Q51– An MRI RF coil at 1 T has induced voltage magnitude V =2 0V sM 0()Br, with γ₀ the Larmor…
GATE 2026 BM Q33– An MRI signal has T2=100 ms and initial intensity 500 a.u. Find the intensity at t=50 ms,…
GATE 2026 BM Q34– The gyromagnetic frequency ratio of ³¹P is 17.23 MHz/T. Find its Larmor frequency at 3 T,…
GATE 2026 BM Q47– The shown MRI pulse sequence marks repetition time TR and echo time TE. Identify it.
GATE 2025 BM Q14– Statement (i): Structural MRI has better spatial resolution than EEG. Statement (ii): EEG…
GATE 2025 BM Q62– Proton gyromagnetic frequency ratio is 42.58 MHz/T. Find resonance frequency at 1.5 T to…