Table 1.
Comparison of the spatial resolution and cell detection sensitivity of the different imaging modalities discusseda
| Monitoring strategy | Spatial resolution | Cell detection sensitivity |
|---|---|---|
| Direct labeling | ||
| PET/SPECT | 3+ | 3+ |
| MRI | 4+ | 3+ |
| Indirect labeling (reporter genes) | ||
| PET | 3+ | 3+ |
| SPECT | 3+ | 3+ |
| MRI | 4+ | Unknown |
MRI magnetic resonance imaging, PET positron emission tomography, SPECT single photon emission computed tomography
a
Scale is semiquantitative: 1+ to 4+ (from least to best spatial resolution/cell detection sensitivity).
Note that these are qualitative indices and other factors such as depth of signal in optical imaging, preloading of cells with imaging agent(s), and the imaging instrument being used can markedly influence the results. (Adapted from Rodriguez-Porcel et al. [51]; with permission.)