Table 1.

Cerebral and retinal structural and vascular biomarkers associated with carotid artery disease

Structural and vascular biomarkers	Imaging technique	Quantification possible?	Reason in favor of use	Principal limitation
Carotid morphology	CTA MRI	NASCET criteria	Anatomical structures variance assessment Plaque analysis	Over estimation of calcification Under estimation of calcification
Carotid blood flow velocity	DUS	PVS > 125 cm/s EDV > 140 cm/s	Real-time hemodynamical information	Investigator dependent
Cerebral morphology	CTA or MRI	No	Subacute and chronic ischemic lesion detection Anatomical structures variance assessment	Image resolution limits the visualization of smaller vessel
Cerebral blood flow velocity	TCD	No	Measurement the cerebral reserve capacity	20% of patients lack of TCD window
Retinal neuronal changes
Macular RNFL thinning	OCT	Yes	Quantification of retinal neural damage	Lack of information on retinal blood flow
Peripapillar RNFL thinning		Yes
GCL-IPL thinning		Yes
Retinal vascular changes
VD decrease	OCTA	Yes	Quantification of retinal capillary blood-flow	Not part of routine clinical practice
FAZ enlargement		Yes

DUS duplex ultrasound, PVS peak systolic velocity, EDV end diastolic velocity, CTA computed tomography angiography, MRI magnetic resonance imaging, TCD transcranial Doppler, OCT optical coherence tomography, OCTA optical coherence tomography angiography, RNFL retinal nerve fiber layer, GCL-ICL ganglion cell layer-inner plexiform layer, VD vessel density, FAZ fovea avascular zone