Diagnostic and prognostic utility of non-invasive imaging in diabetes management

Table 1 Relevant features of the most common imaging modalities

Imaging modality	Anatomy	Metabolism/ function	Spatial resolution	Weakness
SPECT	Poor	Yes	0.3-3 mm	Radiation
PET	Poor	Yes	1-4 mm	Radiation
CT	Yes	Yes	0.5-1 mm	Radiation
MRI	Yes	Yes	50-500 μm	Expensive
Ultrasound	Yes	Yes	Approximately 200 μm	Poor depth penetration
Optical	Poor	Yes	0.1-10 mm	Poor depth penetration

SPECT: Single-photon emission computed tomography; PET: Positron emission tomography; CT: Computed tomography; MRI: Magnetic resonance imaging.

Table 2 Main nuclides used in nuclear medicine to label radiopharmaceuticals

SPECT			PET
Nuclide	Half-life	γ (KeV%)	Nuclide	Half-life	β+ (KeV%)
99mTc	6.02 h	89	18F	109.8 min	96.9
111In	2.83 d	90.2	11C	20.4 min	99.7
123I	13.2 h	83	13N	9.98 min	99.8
125I	60.14 d	6.5	15O	2.03 min	99.9
			124I	4.18 d	25.0
			64Cu	12.7 h	17.9
			68Ga	68 min	90.0
			82Rb	1.2 min	99.9

Radiation types: γ: Isomeric transition (gamma) decay; β⁺: Positron decay; KeV%: Percentage of energy per decay. SPECT: Single-photon emission computed tomography; PET: Positron emission tomography.

Table 3 Synopsis of imaging modalities and their applications in diabetes

	SPECT/PET	CT	MR	US	Optical	Application
Pancreas (β-cell function)	[18F]-tracer		MRI		Luminescence	Mainly preclinical[61,62]
Pancreas (transplant/ inflammation)	[18F]-tracer		MRI	High-frequency		Preclinical and clinical[63-68]
Kidney			MRI/BOLD-MRI	B-mode/Doppler		Clinical[70-78]
Brain	[123I]- and [99Tc]-tracer		MRI/MRS	Doppler		Clinical[22,82,83]
Vessels/atherosclerosis	[18F]-tracer	Angio-CT	MRI	B-mode		Clinical[85-95,100-106]
Ulcerations	[99Tc]-tracer	Hybrid SPECT/CT	MRI	Doppler	HIS	Clinical[113,114,116,117]
Heart	[18F]-, [123I]- [11C]-tracer	Hybrid PET/CT	MRI/MRS	Doppler		Clinical[95,120-126,130,131,134,135]
Visceral fat		CT/dual energy CT	MRI/MRS	B-mode		Clinical[142,145,146]

SPECT: Single-photon emission computed tomography; PET: Positron emission tomography; CT: Computed tomography; MRI: Magnetic resonance imaging; US: Ultrasound; MRS: Magnetic resonance spectroscopy; BOLD: Blood-oxygen-level-dependent; HIS: Hyperspectral imaging.