Table 3. Advantages and disadvantages of PET, MRI, and US.

	Advantages	Disadvantages
PET	Imaging of islets functionally High resolution Good sensitivity No necessity for islet labeling before transplantation	Ionizing radiation No anatomical information Low spatial resolution (single transplanted islets cannot be visualized)
MRI	High resolution High spatial resolution No ionizing radiation	Necessity of labeling islets before transplantation Toxicity of agent Difficulty of distinguishing between live and dead islets
US	No adverse events for patients Can be performed at bedside	No methodology to visualize single islets at present