Quantitative susceptibility mapping at 3 T: comparison of acquisition methodologies

Area of Science:

• Radiology
• Neuroimaging
• Medical Physics

Background:

• Quantitative susceptibility mapping (QSM) is increasingly used for neurological disease assessment.
• Standardized QSM scanning protocols are lacking, raising questions about acquisition parameter influence.

Purpose of the Study:

• To evaluate the impact of different QSM acquisition parameters on deep grey matter susceptibility values in healthy adults.
• To determine if unipolar/bipolar gradients, accelerated imaging, or gradient-warp correction affect QSM results.

Main Methods:

• Four healthy adults underwent repeated 3T MRI scans using various QSM sequences.
• Acquisition parameters included unipolar/bipolar gradients, accelerated imaging, and gradient-warp correction.
• Linear mixed-effects models analyzed susceptibility values in deep grey matter structures.

Main Results:

• Gradient-warp correction was the only statistically significant factor, causing a small (~5%) change in susceptibility values.
• Accelerated imaging and gradient types (unipolar/bipolar) did not significantly alter deep grey matter susceptibility.
• Tissue-specific variations (random effects) were statistically significant.

Conclusions:

• QSM susceptibility values in deep grey matter are largely consistent across different acquisition strategies, excluding gradient-warp correction.
• Gradient-warp correction introduces a minor but statistically significant adjustment to QSM measurements.
• Further standardization of QSM protocols may be beneficial, considering the impact of gradient-warp correction.