Optimal Labeling Dose, Labeling Time, and Magnetic Resonance Imaging Detection Limits of Ultrasmall Superparamagnetic Iron-Oxide Nanoparticle Labeled Mesenchymal Stromal Cells

Table 5

MRI intensity differences after 2-hour USPIO incubation.

USPIO dose	1×10^6 cells	5×10^5 cells	2.5×10^5 cells
Full	59±65	57±39	60±68
Half	39±38	36±62	41±70
Unlabeled	71±46	101±41	55±39
	ns	ns	ns

The MRI intensities are mean pixel intensities (values between 0 and 4095) of a 20 mm² region of interest in the center area of each phantom, supplied by the imaging software. Values are shown ± SD.
USPIO: ultrasmall super-paramagnetic iron-oxide. USPIO dose—full = 10 𝜇g per 10⁵ cells; half = 5 𝜇g per 10⁵ cells. ns: non-significant.