Optimizing Selective RF Pulses for Enhanced Signal Stability in Turbo Spin Echo Using a Differentiable Extended Phase Graph Model

Motivation: Slice profile inconsistencies across echoes in TSE introduce image ghosting and blurring. Goal(s): To jointly design RF pulses for slice profile consistency using a comprehensive model of the magnetization pathways. Approach: We jointly optimized the RF pulses for TSE using a differentiable extended phase graph model by minimizing an error term on the target echo magnitude with singular value regularization to promote similarity. Results: Optimized pulses demonstrated superior performance over SLR pulses, showing 92% reduction in slice profile FWHM variation in phantom experiments and reduced ghosting and blurring in head images. Impact: We present an RF pulse optimization method that uses a differentiable EPG model to increase slice profile consistency across TSE echoes. The optimized pulses reduced blurring and ghosting in TSE images, with potential applications to other echo train sequences.