Magnetic Resonance Imaging (MRI)

Fig. 1 The basis of high-sensitivity SPION imaging at ultra-low magnetic fields.

(A) Magnetization of 25-nm SPIONs (green), gadolinium CA (Gd-DTPA/Magnevist, blue), and water (red) as a function of magnetic field strength (B0). (B) Magnetization as a function of magnetic field strength (B0) in the ULF (<10 mT) regime for the materials shown in (A). Superparamagnetic materials, such as SPIONs, are highly magnetized even at ULF. Paramagnetic materials, such as CAs based on gadolinium, and body tissues (which typically have diamagnetic susceptibilities close to water) have absolute magnetizations that increase linearly with field strength. Curves in (A) and (B) were reproduced from data in (32, 53) and reflect the magnetic moment per kilogram of compound. (C) Highly magnetized SPIONs (brown) interact with nearby 1H spins in water, shortening 1H relaxation times, and causing susceptibility-based shifts in Larmor frequency. Image courtesy of Science Advances

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R2* maps of healthy control participants and participants with Alzheimer disease. R2* maps are windowed between 10 and 50 sec21. Differences in iron concentration in basal ganglia are too small to allow visual separation between patients with Alzheimer disease and control participants, and iron levels strongly depend on anatomic structure and subject age. Image courtesy of Radiological Society of North America

Cardiac MR can offer data above and beyond anatomical imaging, which is the main reason why this system was installed at Baylor Scott White Heart Hospital in Dallas. The system is a dedicated heart MRI scanner.