Table 2 Summary of recent studies investigating the use of magnetic particle imaging (MPI) for imaging and detecting brain diseases

Xenograft tumor-in-situ glioma mice

Multimodality nanoparticles

MOMENTUM preclinical scanner (FFP, X-space)

MPI signals in brain tissue can increase 17.1 times after injection and MPI signals can be observed with rich blood supply

[26]

Xenograft tumor-in-situ glioma mice

FeCo@C

MOMENTUM preclinical scanner (FFP, X-space)

FeCo@C provides an MPI signal intensity that is 6-time and 15-time higher than the signals from VivoTrax and Feraheme, respectively

[48]

Xenograft tumor-in-situ glioma mice

Nanoparticles-covered the membrane of glioblastoma cells

MOMENTUM preclinical scanner (FFP, X-space)

MPI signal does not decay with tissue depth and shows excellent sensitivity for thousands of cells

[66]

Brain cancer xenografts

Lactoferrin-functionalized nanoparticles

MOMENTUM preclinical scanner (FFP, X-space)

The agent can detect 1.1 ng of iron (SNR was about 3.9). Lactoferrin coupling and external magnet can improve the tumor localization

[70]

C6 brain glioma cells in vitro

Lactoferrin-functionalized nanoparticles

Custom-built magnetic particle spectrometer

Nanoparticles with Lactoferrin have increased 5 times signal intensity compared to non-targeted particles

[87]

Neural progenitor cells in rat

Resovist

Custom-built MPI systems (FFL, X-space)

The detection limit is 200 cells (5.4 ng Fe) in vitro, and in vivo monitoring of human neural graft clearance is over 87 d in rat brain

[33]

Cerebral perfusion in healthy mice

Perimag

Dedicated surface coil for mice (FFP, system matrix)

MPI can detect tracer samples containing only 896 pg iron (about 69 cells), and even small vessels (150 µm diameter) and anatomical structures

[68]

Ischemic stroke model in mice

LS-008

Bruker preclinical

System (FFP, system matrix)

MPI can be used for real time detection of perfusion deficits associated with ischemic stroke

[60]

Intracranial hemorrhage model in mice

Perimag and Synomag-D

Bruker preclinical system (FFP, system matrix)

Multi-contrast MPI can differentiate clotted blood from active bleeding. The bleed can be detected in 3 min, and the quantitative range is 0.003 – 0.06 μl/s

[61]

Healthy rhesus macaque

Mag3200

Hand-held MPI

detector

The detector has a detection limit of about 125 ng Fe and can in vivo measure cerebral particle concentration changes

[88]

Stroke phantom

Perimag

Novel MPI head scanner (FFP, system matrix)

A system can achieve a sensitivity limit of 14.7 ng Fe/ml at a frame rate of 2 Hz and a spatial resolution of 5 mm

[56]

Hypercapnic model in rat

SPIONs with a 25 nm core and a polyethylene glycol carboxyl coating

Single-sided detector

MPI could measure CBV changes during hypercapnia with a CNR of 50

[57]

Hypercapnia model in rat

Synomag-D

Home-built rodent scanner (FFL, system matrix)

The average CNR of CBV in fMPI was approximately 2 – 6 times higher than that in fMRI

[62]