Evaluation of Phantom Doping Materials in Quantitative Susceptibility Mapping

Area of Science:

• Medical Imaging
• Biophysics
• Materials Science

Background:

• Quantitative Susceptibility Mapping (QSM) is crucial for estimating magnetic susceptibility (χ).
• Repeatability of QSM measurements is essential for reliable clinical applications.
• Developing standardized phantoms with relevant doping materials is key for QSM validation.

Purpose of the Study:

• To measure magnetic susceptibility (χ) using Quantitative Susceptibility Mapping (QSM).
• To evaluate the repeatability of QSM measurements with four phantom doping materials.
• To assess the suitability of these materials for QSM applications.

Main Methods:

• A phantom with agarose gel doped with ferritin, USPIO, CaCl2, and CaCO3 was created.
• Single orientation QSM measurements were performed at 3 and 7 Tesla.
• Molar susceptibility (χmol) was measured, and precision was assessed using standard deviation (SDROI).

Main Results:

• Molar susceptibilities (χmol) were quantified for all dopants at both field strengths.
• Ferritin and CaCO3 showed no significant changes in molar susceptibility over time (24 and 15 months, respectively).
• Specific χmol values were reported for USPIO, Ferritin, CaCl2, and CaCO3 at 3T and 7T.

Conclusions:

• Ferritin is recommended as a suitable paramagnetic dopant for QSM.
• Further research is needed to find diamagnetic dopants with improved properties.
• Optimizing dopant selection enhances the accuracy and reliability of QSM.