Table 2.

Comparison of imaging techniques for visualization of vascular systems in skeletal muscle.

technique	excitation signal	maximum spatial resolution	2D/3D	penetration depth	tissue preparation	acquisition time	in vivo/ex vivo
light microscopy (LM)	light	0.2 µm	2D	—	staining	seconds	ex vivo
confocal laser scanning microscopy (CLSM)	light laser	0.1 µm	2D	150 µm	fluorescent staining	minutes	ex vivo
light sheet fluorescence microscopy (LSFM)	light laser	0.2 µm	2D	1 cm	fluorescent staining	hours	ex vivo
single photon laser scanning microscopy (SPLSM)	light laser	0.2 µm	2D	—	fluorescent staining	minutes	in vivo
multi-photon laser scanning microscopy (MPLSM)	light laser	0.2 µm	2D	1 mm	fluorescent staining	minutes	in vivo
optical coherence tomography (OCT)	light laser	5 µm	3D	2 mm	—	minutes	in vivo
laser speckle contrast imaging (LS)	light laser	10 µm	2D	1 mm	—	minutes	in vivo
laser Doppler flowmetry (LDF)	light laser	10 µm	2D	1 mm	—	minutes	in vivo
serial block-face scanning electron microscopy (SBF SEM)	electron beam	2 nm	3D	500 µm	heavy metal staining	hours	ex vivo
transmission electron microscopy (TEM)	electron beam	0.2 nm	2D	100 nm	heavy metal staining	minutes	ex vivo
micro-computed tomography (μCT)	X-rays	0.7 µm	3D	1 m	staining or perfusion	hours	ex vivo
synchrotron radiation-based computed tomography (SR CT)	X-rays	0.3 µm	3D	1 m	staining or perfusion	minutes	ex vivo
micro-focused magnetic resonance imaging (μMRI)	magnetic pulse	60 µm	3D	1 m	contrast agent perfusion	hours	in vivo
positron emission tomography (PET/SPECT)	positrons	1–2 mm	3D	1 m	contrast agent perfusion	hours	in vivo
photoacoustic tomography (PAT)	acoustic waves	50 µm	3D	1 mm	—	hours	in vivo