Highly-accelerated volumetric brain examination using optimized wave-CAIPI encoding.

ABSTRACT: BACKGROUND:Rapid volumetric imaging protocols could better utilize limited scanner resources. PURPOSE:To develop and validate an optimized 6-minute high-resolution volumetric brain MRI examination using Wave-CAIPI encoding. STUDY TYPE:Prospective. POPULATION/SUBJECTS:Ten healthy subjects and 20 patients with a variety of intracranial pathologies. FIELD STRENGTH/SEQUENCE:At 3?T, MPRAGE, T2 -weighted SPACE, SPACE FLAIR, and SWI were acquired at 9-fold acceleration using Wave-CAIPI and for comparison at 2-4-fold acceleration using conventional GRAPPA. ASSESSMENT:Extensive simulations were performed to optimize the Wave-CAIPI protocol and minimize both g-factor noise amplification and potential T1 /T2 blurring artifacts. Moreover, refinements in the autocalibrated reconstruction of Wave-CAIPI were developed to ensure high-quality reconstructions in the presence of gradient imperfections. In a randomized and blinded fashion, three neuroradiologists assessed the diagnostic quality of the optimized 6-minute Wave-CAIPI exam and compared it to the roughly 3× slower GRAPPA accelerated protocol using both an individual and head-to-head analysis. STATISTICAL TEST:A noninferiority test was used to test whether the diagnostic quality of Wave-CAIPI was noninferior to the GRAPPA acquisition, with a 15% noninferiority margin. RESULTS:Among all sequences, Wave-CAIPI achieved negligible g-factor noise amplification (gavg ???1.04) and burring artifacts from T1 /T2 relaxation. Improvements of our autocalibration approach for gradient imperfections enabled increased robustness to gradient mixing imperfections in tilted-field of view (FOV) prescriptions as well as variations in gradient and analog-to-digital converter (ADC) sampling rates. In the clinical evaluation, Wave-CAIPI achieved similar mean scores when compared with GRAPPA (MPRAGE: ØW ?=?4.03, ØG ?=?3.97; T2 w SPACE: ØW ?=?4.00, ØG ?=?4.00; SPACE FLAIR: ØW ?= 3.97, ØG ?=?3.97; SWI: ØW ?=?3.93, ØG ?=?3.83) and was statistically noninferior (N?=?30, P?

SUBMITTER: Polak D 

PROVIDER: S-EPMC6687581 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature