Optical coherence tomography and angiography in Alzheimer's disease and other cognitive disorders

Abstract

Aims The aims of this study were to analyze retinal and choroidal changes on optical coherence tomography (OCT) and OCT-Angiography (OCT-A) in Alzheimer's disease (AD) patients and compare them to other forms of major dementia. We also aimed to analyze the correlation between clinical severity of global cognitive deficiency assessed by the mini-mental state exam (MMSE) score and OCT/OCT-A parameters. Methods Retrospective cross-sectional evaluative study of AD, and age-and gender-matched patients with other dementias. Fundus examination, OCT and OCT-A were compared. Results Ninety-one eyes of AD patients and 53 eyes of patients with other dementias were included. Retinal deposits were found in 6.59% of AD cases. OCT highlighted the presence of hyperreflective deposits and localized areas of outer retina and ellipsoid zone disruption, respectively in 20.87% and 15.38% of AD cases. Hyperreflective foci were noted within inner retinal layers in 4.39% of AD cases. Quantitative analysis revealed a thicker nasal retinal nerve fiber layer (p = 0.001) and ganglion cell complex in superior (p = 0.011) and temporal quadrants (p = 0.009) in eyes of AD patients, compared to other dementias. OCT-A showed a significantly higher fractal dimension of both superficial and deep capillary plexus (p = 0.005), with lower choriocapillaris density (p = 0.003) in AD patients. Conclusions Structural OCT could highlight the presence of hyperreflective deposits in AD, probably reflecting beta-amyloid deposits, associated to outer retinal disruptions. Quantitative OCT analysis showed structural differences between AD patients and other dementias, and combined OCT-A could identify microvascular changes in AD patients representing new potential differential diagnosis criteria.

Optical Coherence Tomography Angiography: Revolutionizing Clinical Diagnostics and Treatment in Central Nervous System Disease

“…FAZ area was lager in comparison to HC [10,29,37]. Researchers have also found that correlations between SRCP and disease duration [23], degree of cognitive impairment [23,36,42,49], and brain parenchymal volume [50] in AD patients continue to manifest. Biscetti et al found that the retinal FD is correlated with the CSF Aβ42/t-tau ratio [43].…”

“…Some studies have shown that the fundus of AD patients are not significantly different from the HC [14,15]. Nevertheless, more studies have found that the thickness of multiple retinal layers is significantly lower in AD patients compared to HC, including whole retinal thickness [16][17][18][19][20], ganglion cell plexiform layer (GC-IPL) [1,16,19,21,22], ganglion cell complex (GCC) [23], outer retinal layer [24] and RNFL [16,17,19,23,[25][26][27][28][29]. There was also a significant reduction in choroidal thickness [10,11,[30][31][32][33][34].…”

“…It may indicate that retinal thickness can reflect AD progression. Moreover, retinal thickness was discovered to be associated with the degree of cognitive impairment (MMSE and MoCA scores) [19,20,23,35], brain parenchymal volume [35] and the amount of Aβ amyloid and tau protein in the CSF [22] in AD patients. Using OCTA to further look at retinal and choroidal blood flow parameters in AD patients, the investigators found that retinal blood flow was significantly lower than in HC [10,19].…”

“…However, whether specific changes occur in the retina and choroid of AD patients remains to be further explored by researchers. In a recent 2023 study using OCTA to observe the effects of dementia on the retina, patients with AD-related dementia had thicker RNFL and GCC in the nasal sector and higher FD in SRCP and DRCP than other dementia populations, but had significantly lower VD in the CC [23]. It is likely to represent that the effects of AD on the retina are somewhat specific.…”

Optical coherence tomography with angiography in the diagnosis of Alzheimer’s disease

“…В рамках исследования Atherosclerosis Risk in Communities (ARIC) продемонстрировано, что некоторые редкие аномалии сетчатки глаза могут предсказать снижение когнитивных способностей и возникновение деменции [23,24]. В недавнем исследовании было показано, что количественный анализ ОКТ может помочь дифференцировать БА от других видов деменции, а ОКТА -выявить микрососудистые изменения у пациентов с БА, представляющие собой новые потенциальные критерии дифференциальной диагностики [25].…”