BOLD signal simulation and fMRI quality control base on an active phantom: a preliminary study.

Area of Science:

• Medical Imaging
• Biophysics
• Neuroimaging

Background:

• Functional magnetic resonance imaging (fMRI) commonly uses the blood-oxygen-level-dependent (BOLD) signal to map brain activity.
• Simulating the BOLD signal is challenging due to its low amplitude (1-3%) and sensitivity to multiple factors.
• Quantitative quality control for fMRI is essential for reliable and reproducible results.

Purpose of the Study:

• To design and construct an active phantom capable of simulating BOLD signals.
• To evaluate the stability and repeatability of the designed phantom across different MRI scanners.
• To assess the phantom's utility for quantitative quality control in fMRI.

Main Methods:

• An active phantom with two perpendicular loops was constructed to simulate BOLD signals via controlled vibration currents.
• The phantom's BOLD signal simulation was tested on three MRI scanners: Siemens Skyra (3.0 T), Siemens Verio (3.0 T), and GE Signa (1.5 T).
• Stability, repeatability, signal-to-noise ratio (SNR), ghosting ratio, and stimuli detection efficiency were quantified.

Main Results:

• The phantom demonstrated high stability at baseline with average signal variation below 1% across scanners.
• High SNR values (2326.58 and 2389.24) and low ghosting ratios (0.39% and 0.38%) were achieved.
• Percent signal change (PSC) values ranged from 1-3% across scanners, with consistent activation areas detected, indicating high reproducibility.

Conclusions:

• The developed active phantom reliably simulates BOLD signals for fMRI.
• The phantom exhibits excellent adaptability to different MRI scanners and is easy to operate.
• This phantom serves as a valuable tool for quantitative quality control in fMRI, enhancing data reliability.