Quantitative Analysis of Retinal Perfusion in Patients with Frontotemporal Dementia Using Optical Coherence Tomography Angiography

Abstract

Background: Optical coherence tomography angiography (OCT-A) provides detailed visualization of the perfusion of the vascular network of the eye. While in other forms of dementia, such as Alzheimer's disease and mild cognitive impairment, reduced retinal perfusion was frequently reported, data of patients with frontotemporal dementia (FTD) are lacking.

Objective: Retinal and optic nerve head perfusion was evaluated in patients with FTD with OCT-A. Quantitative OCT-A metrics were analyzed and correlated with clinical markers and vascular cerebral lesions in FTD patients.

Methods: OCT-A was performed in 18 eyes of 18 patients with FTD and 18 eyes of 18 healthy participants using RTVue XR Avanti with AngioVue. In addition, patients underwent a detailed ophthalmological, neurological, and neuropsychological examination, cerebral magnetic resonance imaging (MRI), and lumbar puncture.

Results: The flow density in the optic nerve head (ONH) and in the superficial capillary plexus (SCP) of the macula of patients was significantly lower compared to that of healthy controls (p < 0.001). Similarly, the VD in the deep capillary plexus (DCP) of the macula of patients was significantly lower compared to that of healthy controls (p < 0.001). There was no significant correlation between the flow density data, white matter lesions in brain MRI, cognitive deficits, and cerebrospinal fluid markers of dementia.

Conclusions: Patients with FTD showed a reduced flow density in the ONH, and in the superficial and deep retinal capillary plexus of the macula, when compared with that of healthy controls. Quantitative analyses of retinal perfusion using OCT-A may therefore help in the diagnosis and monitoring of FTD. Larger and longitudinal studies are necessary to evaluate if OCT-A is a suitable biomarker for patients with FTD.

Keywords: flow density; frontotemporal dementia; optical coherence tomography angiography; retinal and optic nerve head perfusion.

Figure 1

The macula (A) and color-coded vascular density maps (B) from superficial retinal OCT angiograms in a frontotemporal dementia (FTD) patient and a healthy control. Three different flow densities were analyzed: the parafoveal flow density (diameter from 1 mm to 2.5 mm), the whole en face flow density (average flow density of the complete 2.5 mm circle), and the foveal flow density (small white circle with a diameter of 1 mm).

Figure 2

Comparison of the flow density (%) obtained in the superficial and deep capillary plexus of the macula and optic disc OCT angiogram in patients with FTD and healthy controls (p < 0.001). **** = statistically highly significant.