Evaluation of dual-source parallel RF excitation technology in MRI of thoraco-lumbar spine at 3.0 T

Abstract

High-field 3 T magnetic resonance imaging (MRI) has entered standard clinical practice over the past decade, and its advantages have already been suggested in areas such as neural, musculoskeletal, pelvic and angiographic imaging. However, high-field systems still pose challenges in terms of their specific absorption rate (SAR) and radiofrequency (RF) excitation uniformity. Thus, the aim of the present study was to evaluate the impact, on both these factors, of standard quadrature against parallel RF transmission technology (dual-source parallel RF excitation [DSPE]) in spinal examination at 3 T. The thoracolumbar spine was examined with three different sequences: T1-weighted (T1w); T2-weighted (T2w); and T2w short tau inversion recovery (STIR). Each was acquired with and without DSPE. The manufacturer's implementation of this technology has been associated with optimized handling of patient SAR exposure, resulting in a 38.4% reduction in acquisition time. On comparing sequences with equal repetition times (TRs), the acquisition time reduction was 44.4%. Thus, DSPE allows a reduction in acquisition time. This gain is accompanied by augmentation of the whole-body SAR and diminution of the local SAR. Image quality improvement due to more homogeneous effective transmit B1 was mainly observed at the junction of the thoracolumbar spine.