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Updated: Jun 2, 2026
Using Retinal Imaging to Study Dementia
Published on: November 6, 2017
Fractal analysis reveals reduced complexity of retinal vessels in CADASIL
Michele Cavallari1, Teresa Falco, Marina Frontali
1Department of Neurosciences, Mental Health and Sensory Organs, Sant'Andrea Hospital, University of Rome La Sapienza, Rome, Italy.
Insights
Fractal analysis of retinal images revealed reduced vessel complexity in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) patients. This finding may indicate early microvascular changes in the brain, offering a new diagnostic approach for CADASIL.
Area of Science:
- Neurology
- Ophthalmology
- Medical Imaging
Background:
- Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a genetic disorder affecting cerebral small arteries, leading to cognitive decline and dementia.
- Current understanding of CADASIL's microvessel pathology progression is limited due to the lack of in vivo brain imaging tools.
- Ophthalmoscopy offers a potential non-invasive method to assess cerebral microcirculation.
Purpose of the Study:
- To investigate the utility of fractal analysis of retinal photographs as a tool to detect microvascular changes in CADASIL.
- To explore the relationship between retinal vascular complexity and disease severity or duration in CADASIL patients.
Main Methods:
- Digital retinal photographs were obtained from 10 CADASIL patients and 10 age- and sex-matched controls.
- Fractal analysis was used to quantify retinal vessel branching complexity, expressed as mean fractal dimension (mean-D).
- Brain MRI lesion volumes were assessed, and correlations between mean-D, disease duration, and lesion volume were analyzed.
Main Results:
- CADASIL patients exhibited significantly lower mean-D values (1.42±0.05) compared to controls (1.50±0.04; p=0.002).
- No significant correlation was found between mean-D and disease duration or brain MRI lesion volumes in CADASIL patients.
- Fractal analysis demonstrated sensitivity in detecting altered retinal vessel branching patterns.
Conclusions:
- Fractal analysis of retinal vasculature is a sensitive method for identifying microvascular alterations in CADASIL.
- These retinal changes may reflect early, subclinical microvessel pathology in the brain.
- This technique holds promise as a non-invasive tool for monitoring CADASIL progression and evaluating therapeutic interventions.
Abstract:
The Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) affects mainly small cerebral arteries and leads to disability and dementia. The relationship between clinical expression of the disease and progression of the microvessel pathology is, however, uncertain as we lack tools for imaging brain vessels in vivo. Ophthalmoscopy is regarded as a window into the cerebral microcirculation. In this study we carried out an ophthalmoscopic examination in subjects with CADASIL. Specifically, we performed fractal analysis of digital retinal photographs. Data are expressed as mean fractal dimension (mean-D), a parameter that reflects complexity of the retinal vessel branching. Ten subjects with genetically confirmed diagnosis of CADASIL and 10 sex and age-matched control subjects were enrolled. Fractal analysis of retinal digital images was performed by means of a computer-based program, and the data expressed as mean-D. Brain MRI lesion volume in FLAIR and T1-weighted images was assessed using MIPAV software. Paired t-test was used to disclose differences in mean-D between CADASIL and control groups. Spearman rank analysis was performed to evaluate potential associations between mean-D values and both disease duration and disease severity, the latter expressed as brain MRI lesion volumes, in the subjects with CADASIL. The results showed that mean-D value of patients (1.42±0.05; mean±SD) was lower than control (1.50±0.04; p = 0.002). Mean-D did not correlate with disease duration nor with MRI lesion volumes of the subjects with CADASIL. The findings suggest that fractal analysis is a sensitive tool to assess changes of retinal vessel branching, likely reflecting early brain microvessel alterations, in CADASIL patients.
