Molecular Imaging in Stem Cell Therapy for Spinal Cord Injury

Table 2

Advantages and limitations of different imaging methods for detection of grafted stem cells (modified from Modo et al. [81] and Spiriev et al. [82]).

Imaging modality	PET	MRI	BLI	FLI
Depth of penetration	No limit	No limit	1-2 mm	<1 mm
Spatial resolution	1-2 mm	10–100 μm	Several mm	2-3 mm
Temporal resolution	sec–min	min–hrs	sec–min	sec–min
Imaging agents	Radionuclide labeled compound	Gadolinium,; dysprosium; iron oxide particles	Luciferins	Fluorescent protein
Toxicity	No	Yes	No	No
Time range of detection	6–12 months	1-2 months	2–8 weeks	Long-term
Detection limits in terms of cell numbers in vivo	1 × 10^4–1 × 10^5	5 × 10^5–1 × 10^6	1 × 10^3–1 × 10^6	2 × 10^4–5 × 10^5

Sec: second, min: minute, and hrs: hours.