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Table 2 Stem cell tracking strategies for cardiovascular applications in vivo

From: Tracking of stem cells in vivo for cardiovascular applications

Physical principle


Cell labels



Tissue contrast based

Magnetic field change


• Iron oxides

• High spatial resolution

• Low sensitivity

• Gad-chelates

• Signal not linked to cell viability

• Microcapsules

• High anatomic detail

• Reporter genes (enzyme-based, transporter-based)

• Lack of CMR-compatible devices for interactivity

• No ionizing radiation

• Post-processing capabilities

• Not compatible for patients with implants

• Permits medium-term tracking

• Expensive

• Acoustic noise

Electron density change


• Gold Nanoparticles

• High sensitivity

• Ionizing radiation

• Microcapsules

• High potential of real-time interactivity

• Limited spatial resolution

• Lacks soft tissue detail

Echogenicity change


• Liposomes

• High potential of real-time interactivity

• Difficultly with thin/obese patients

• Microbubbles

• Microcapsules

• Highly operator dependent

• Perfluorocarbons

• No ionizing radiation

• Interpretation has high learning curve

• Inexpensive

• Highly portable

• Limited resolution

• Acoustic artifacts may compromise image

Photon emission based

Radionuclide imaging (High energy ionizing radiation)


• Reporter genes, e.g. HSV-tk, hNIS

• High sensitivity

• Poor anatomic detail

• High translational capacity

• Poor interactivity

• Radionuclides, e.g. 18 F-FHBG, 124I FIAU, and 18 F-FDG

• Ionizing radiation

• Temporal limitations (due to radioactive decay)


• Radionuclides, e.g. 111In oxine, 99mTc and18 F FDG

• Concerns for label-induced cellular toxicity

• Biohazardous labels

• Expensive

Optical imaging (Low energy radiation)


• Reporter genes, e.g. luciferase

• Permits longitudinal monitoring

• Limited spatial resolution

• Lacks clinical relevance

• Low background

• No excitation light required

• Biohazardous labels


• Fluorophores, e.g. GFP

• High sensitivity

• Photon attenuation w/cell division

• Multiplexing

• Near-infrared probes

• No ionizing radiation

• Autofluorescence yields high background

• Quantum dots

• Low cost

• Small depth of high-resolution

• Permits short-term tracking

• Biohazardous labels

  1. BLI: Bioluminescence imaging; 18F FDG: Fluoro-2-deoxy-d-glucose; FHBG: Fluoro-3-hydroxymethylbutyl; GFP: green fluorescent protein; 111In: Indium; PET: Positron emission tomography; SPECT: Single photoelectron computed tomography; 99mTc: Technetium; US: Ultrasound.