A diffusion‐based method for long‐ T 2 suppression in steady state sequences: Validation and application for 3D‐UTE imaging

Purpose To introduce a novel method for long‐ T 2 signal physical suppression in steady‐state based on configuration states combination and modulation using diffusion weighting. Its efficiency in yielding a high contrast in short‐ T 2 structures using an ultrashort echo time acquisition module (Diff‐UTE) is compared to the adiabatically prepared Inversion‐Recovery‐UTE sequence (IR‐UTE). Theory and Methods Using a rectangular‐pulse prepared 3D‐UTE sequence, the possibility of long‐ T 2 component signal cancellation through diffusion effects is addressed, and the condition met for sets of sequence parameters. Simultaneously, the short‐ T 2 component signal is maximized using a Bloch equation‐based optimization process. The method is evaluated from simulations, and experiments are conducted on a phantom composed of short and long‐ T 2 components, as well as on an ex vivo mouse head. Results Within equal scan times, the proposed method allowed for an efficient long‐ T 2 signal suppression, and expectedly yielded a higher signal to noise ratio in short‐ T 2 structures compared to the IR‐UTE technique, although an intrinsic short‐ T 2 signal loss is expected through the preparation module. Conclusion The Diff‐UTE method represents an interesting alternative to the IR‐UTE technique. Diffusion weighting allowing for a long‐ T 2 suppression results in a less penalizing method to generate a high and selective contrast in short‐ T 2 components. Magn Reson Med 80:548–559, 2018. © 2017 International Society for Magnetic Resonance in Medicine.