A parallel imaging technique using mutual calibration for split‐blade diffusion‐weighted PROPELLER

Abstract

Split-blade diffusion-weighted periodically rotated overlapping parallel lines with enhanced reconstruction (DW-PROPELLER) was proposed to address the issues associated with diffusion-weighted echo planar imaging such as geometric distortion and difficulty in high-resolution imaging. The major drawbacks with DW-PROPELLER are its high SAR (especially at 3T) and violation of the Carr-Purcell-Meiboom-Gill condition, which leads to a long scan time and narrow blade. Parallel imaging can reduce scan time and increase blade width; however, it is very challenging to apply standard k-spacebased techniques such as GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) to split-blade DW-PRO-PELLER due to its narrow blade. In this work, a new calibration scheme is proposed for k-space-based parallel imaging method without the need of additional calibration data, which results in a wider, more stable blade. The in vivo results show that this technique is very promising. Magn Reson Med 65:638-644,

A New Joint-Blade SENSE Reconstruction for Accelerated PROPELLER MRI

“…By reconstructing the central k-space only, joint-blade SENSE may be feasible even without any blade-combined images. Also note that the most complementary blades should be the orthogonal ones 6 , and joint-blade SENSE may be reduced to two-blade SENSE for faster computation if needed. Nevertheless, these potential optimization and simplifications can be addressed in future studies.…”

“…PROPELLER has been widely used for T2-weighted imaging in clinical examinations, where typically each blade is acquired by a single-shot fast spin echo. PROPELLER has also been explored for other applications such as diffusion weighted imaging 3 4 5 6 and water-fat separation 7 8 9 . The main disadvantage of PROPELLER is the increased scan time.…”

Improved motion correction capabilities for fast spin echo T1 FLAIR propeller using non‐Cartesian external calibration data driven parallel imaging

“…External calibration with APPEAR provides several advantages over recent data‐driven parallel imaging methods with PROPELLER in terms of flexibility in the data acquisition geometry, increased number of calibration kernel fit locations, and reduced susceptibility to errors due to inconsistencies in the calibration data. However, it should be noted that the flexibility of the external calibration approach readily allows the combination of this method with recent non‐FSE based PROPELLER methods (5, 18, 32) or that of Li et al (19) to further improve these methods.…”

Rapid PROPELLER‐MRI: A combination of iterative reconstruction and under‐sampling

“…Skare et al (17) used a pair of orthogonal blades for the purpose of auto‐calibration, but this method can be sensitive to motion between these two blades. Recently, Li et al (18) proposed a split blade technique for auto‐calibration. This method reduced imaging time significantly but because of the split blade approach, the effective width of each blade was significantly smaller compared with that in our proposed method, limiting the ability to accurately estimate rotations between blades (2).…”