Variability of clinical functional MR imaging results: a multicenter study

Area of Science:

• Neuroimaging
• Radiology
• Biomarkers

Background:

• Clinical functional magnetic resonance imaging (fMRI) is vital for brain function localization.
• Intersite variability in fMRI data can affect the reliability of clinical diagnoses and research findings.
• Standardization of tasks and data quality assessment are essential for robust fMRI results.

Purpose of the Study:

• To investigate intersite variability in clinical functional MRI.
• To assess the influence of task standardization on fMRI variability.
• To identify parameters for evaluating the reliability of functional localization.

Main Methods:

• Prospective investigation at three experienced fMRI sites using 1.5-T and 3-T scanners.
• Comparison of non-standardized motor and highly standardized somatosensory tasks for sensorimotor cortex localization.
• Assessment of perirolandic fMRI variability using peak activation, center of mass (COM), intraclass correlation, overlap ratio (OR), and activation size ratio.
• Evaluation of data quality using percentage signal change (PSC), contrast-to-noise ratio (CNR), and head motion parameters.

Main Results:

• Significant intersite variability in functional MRI localization, with peak activity differences up to 45.5 mm and COM differences up to 16.5 mm.
• Lower signal strength (PSC, CNR) observed for the standardized somatosensory task compared to the motor task (P < .001).
• Intersite variability increased with lower signal strength, even for standardized tasks.

Conclusions:

• Clinical functional MRI biomarker studies must account for potential center of activation variability up to 16.5 mm across sites.
• Maximizing functional MRI signal strength is critical for reducing intersite variability.
• Reliability of functional localization should be evaluated using metrics like PSC and CNR.