An adiabatic RF pulse in spin‐lock preparations: A double‐edged sword for quantitative R1ρ imaging in clinical applications

Abstract

Adiabatic RF pulses are often used in quantitative R 1 ρ $$ {R}_{1\rho } $$ imaging because of their exceptional immunities to nonuniform magnetic B 0 $$ {B}_0 $$ and B 1 $$ {B}_1 $$ fields. However, the previously reported R 1 ρ $$ {R}_{1\rho } $$ values in biological tissues were comparatively reduced because of an overlooked T 1 $$ {T}_1 $$ relaxation effect within a lengthy pulse duration T p $$ {T}_p $$ . This Letter aimed to remind the readers that an adiabatically prepared spin-locking scheme could introduce bias to R 1 ρ $$ {R}_{1\rho } $$ quantification and thus its nonadiabatic alternative is preferred, particularly for R 1 ρ $$ {R}_{1\rho } $$ dispersion studies.