Referenceless acquisition of phase-sensitive inversion-recovery with decisive reconstruction (RAPID) imaging.

Purpose: To describe a referenceless reconstruction approach to generate phase-sensitive inversion recovery images without relying on the extra acquisition of reference images.

Methods: The basic idea of the Referenceless Acquisition of Phase-sensitive Inversion-recovery with Decisive reconstruction, or RAPID, algorithm is to retrieve the magnetization polarity by estimating the background phase variation of a complex valued image. The theory and algorithm of RAPID is described in detail. To evaluate the performance of RAPID, seven patients were recruited then scanned in different anatomical regions (cardiac, brain, and vascular). Standard Phase Sensitive Inversion Recovery (PSIR) reconstructions using reference image information were compared with RAPID reconstructions using the same source data.

Results: RAPID reconstructed images were found to provide very good agreement with PSIR reconstructed images on all cases, although no reference image info was used in the RAPID algorithm. For neuroimaging applications, it was found that RAPID reconstruction is more robust compared with the PSIR algorithm as RAPID can avoid potential errors introduced by the reference acquisition.

Conclusion: The RAPID technique for phase-sensitive reconstruction is promising and can improve the imaging efficiency by a factor of 2 compared with PSIR. RAPID was also shown to provide more robust reconstruction by avoiding errors caused by the reference acquisition.