Introduction of a new simple dynamic phantom for physical BOLD effect simulation

Abstract

Objective: To propose a new method of simulating the BOLD contrast using a dynamic, easy to construct and operate, low-cost physical phantom.

Materials and methods: A structure of thin pipelines passing through a gel volume was used to simulate blood vessels in human tissue. Quantitative T2*, R2* measurements were used to study the signal change of the phantom. BOLD fMRI experiments and analysis were performed to evaluate its potential use as an fMRI simulator.

Results: Experimental T2*, R2* measurements showed similar behavior with published references. BOLD contrast was successfully achieved with the proposed method. In addition, there were several proposed parameters, like the angle of the phantom relative to B0, which can easily adjust the signal change and the activation area. Coefficients of variation showed good reproducibility within a month period. Statistical t maps were produced with in-house software for the BOLD measurements.

Discussion: T2*maps and BOLD images confirm the potential use of this phantom as an fMRI simulator and also as a tool for studying sensitivity and specificity of BOLD sequences/algorithms.

Keywords: Agarose; BOLD; Phantom; Simulation; fMRI.