Accelerated phase contrast MRI using hybrid one ‐ and two‐sided flow encodings only (HOTFEO)

The aim of this work was to develop and evaluate a fast phase contrast magnetic resonance imaging (PC‐MRI) technique with hybrid one‐ and two‐sided flow encodings only (HOTFEO) for accurate blood flow and velocity measurements of three‐directional velocity encoding PC‐MRI. Four‐dimensional (4D) PC‐MRI acquires flow‐compensated (FC) and three‐directional flow‐encoded (FE) echoes in an interleaved fashion. We hypothesize that the blood flow velocity direction (not magnitude) has minimal change between two consecutive cardiac phases. This assumption provides a velocity direction constraint that can achieve 4/3‐fold acceleration using three‐directional FE data to calculate FC data instead of acquiring them. The HOTFEO acquisition pattern can address the ill‐conditioned constraint and improve the calculation accuracy. HOTFEO was evaluated in healthy volunteers and compared with conventional two‐dimensional (2D) and 4D flow imaging techniques with FC and three‐directional FE acquisitions (FC/3FE). Compared with FC/3FE, Bland–Altman tests showed that the 4/3‐fold accelerated HOTFEO technique resulted in relatively small bias error for total volumetric flow (0.89% for prospective 2D data, –1.19% for retrospective 4D data and –3.40% for prospective 4D data) and maximum peak velocity (0.50% for prospective 2D data, –0.17% for retrospective 4D data and –2.00% for prospective 4D data) measurements in common carotid arteries. HOTFEO can accelerate...

Source: NMR in Biomedicine - March 1, 2018 Category: Radiology Authors: Da Wang, Aichi Chien, Jiaxin Shao, Fadil Abbas Ali, Peng Hu Tags: RESEARCH ARTICLE Source Type: research