Combined ADC and T2 Mapping in the Prostate Using a 3D Reduced FOV Sequence.

PURPOSE: To develop a 3D reduced FOV sequence for combined ADC and T2 mapping in the prostate in a single scan.

METHODS

A 3D ADC and T2 mapping reduced FOV acquisition is enabled using T2 and diffusion preparation modules with slab-selective tip-down pulses and magnitude stabilizer gradients. Imaging shots are followed by 2D phase navigators for phase correction of diffusion-prepared shots and dummy RF pulses for T2-prepared shots, as well as a constant delay to maintain the steady state of the longitudinal magnetization. Mono-exponential fitting is used for ADC and T2 mapping. T2 mapping accuracy was assessed in a phantom against a single-echo spin-echo reference. In vivo, the sequence was compared in the prostate of 11 healthy volunteers against a multi-echo spin-echo acquisition, as well as standard and reduced FOV (rFOV) single-shot EPI (ssEPI).

RESULTS

In the phantom experiments, T2 values were not significantly different from the reference single-echo spin-echo measurements. ADC values in vivo were not significantly different from those obtained using ssEPI. T2 values in vivo showed a mean bias of -21.7 ms compared to those obtained using multi-echo spin-echo with the first echo discarded in the fitting. The proposed sequence achieved similar overall image quality scores to those of ssEPI and rFOV ssEPI, improved perceived distortion scores, but lower perceived SNR scores.

CONCLUSION

The proposed approach enables 3D reduced FOV, single-scan ADC, and T2 mapping with mono-exponential fitting in the prostate.