Retinal and Choroidal Optical Coherence Tomography Findings of Carotid Cavernous Fistula

Microvascular and neural alterations in carotid cavernous fistulas: An optical coherence tomography angiography study

BACKGROUND

Current modalities for diagnosing carotid cavernous fistula (CCF) are inaccurate in analysing retinal microcirculations and nerve fibre changes. Retinal microvascular and neural alterations occur in CCF patients and can be quantitatively measured using optical coherence tomography angiography (OCTA). We measured the neurovascular changes in the eyes of CCF patients and used OCTA as a supplementary method.

METHODS

This cross-sectional study studied 54 eyes of 27 unilateral CCF subjects and 54 eyes of 27 healthy age- and sex-matched controls. OCTA parameters in the macula and optic nerve head (ONH) were analysed using a one-way analysis of variance with further Bonferroni corrections. Parameters with statistical significance were included in a multivariable binary logistic regression analysis and receiver operating characteristic (ROC) curves were generated.

RESULTS

There was significantly less deep-vessel density (DVD) and ONH-associated capillary density in both eyes of CCF patients than in controls, while the differences between the affected and contralateral eyes were insignificant. The retinal nerve fibre layer and ganglion cell complex thickness were lower in the affected eyes than in the contralateral or controlled eyes. ROC curves identified DVD and ONH-associated capillary density as significant parameters in both eyes of CCF patients.

CONCLUSION

The retinal microvascular circulation was affected in both eyes of unilateral CCF patients. Microvascular alterations occurred before retinal neural damage. This quantitative study suggests a supplementary measurement for diagnosing CCF and detecting early neurovascular impairments.

Choroidal arteriovenous anastomoses: a hypothesis for the pathogenesis of central serous chorioretinopathy and other pachychoroid disease spectrum abnormalities

The pachychoroid disease spectrum (PDS) includes several chorioretinal diseases that share specific choroidal abnormalities. Although their pathophysiological basis is poorly understood, diseases that are part of the PDS have been hypothesized to be the result of venous congestion. Within the PDS, central serous chorioretinopathy is the most common condition associated with vision loss, due to an accumulation of subretinal fluid in the macula. Central serous chorioretinopathy is characterized by distinct risk factors, most notably a high prevalence in males and exposure to corticosteroids. Interestingly, sex differences and corticosteroids are also strongly associated with specific types of arteriovenous anastomoses in the human body, including dural arteriovenous fistula and surgically created arteriovenous shunts. In this manuscript, we assess the potential of such arteriovenous anastomoses in the choroid as a causal mechanism of the PDS. We propose how this may provide a novel unifying concept on the pathophysiological basis of the PDS, and present cases in which this mechanism may play a role.

The role of choroidal optical coherence tomography for follow-up of carotid cavernous fistula with anterior drainage

BACKGROUND

To evaluate the role of the choroidal vascularity index (CVI) and the tortuosity index (TI), along with choroidal thickness measurements, in follow-up for anteriorly draining carotid cavernous fistulas (CCF) that would otherwise necessitate an invasive carotid angiogram.

METHODS

In this longitudinal observational study, analysis of enhanced depth imaging spectral domain optical coherence tomography (SD-EDI-OCT) images of 22 patients with angiographically proven unilateral CCF with anterior drainage was performed for subfoveal choroidal thickness (SFCT), central foveal thickness (CFT), CVI and TI. Baseline measurements were compared with those taken at the last visit after occlusion of the fistula.

RESULTS

Both in the clinically affected and unaffected eyes, there was a significant decrease in CFT (p = 0.015 and p = 0.005, respectively), SFCT (p = 0.000 for both eyes), CVI (p = 0.002 and 0.001, respectively) and all three TI parameters, including inferior (p < 0.001 and p = 0.01, respectively) and superior temporal vein tortuosity index (p = 0.005 and p = 0.02, respectively) as well as total venular tortuosity index (p < 0.001 and p = 0.002, respectively) after successful closure of the fistula compared to first presentation. Changes in all parameters were similar between the D-CCF and I-CCF groups except for CVI.

CONCLUSIONS

In this first study concerning follow-up of anteriorly draining unilateral CCFs by SD-EDI-OCT, we not only demonstrated involvement of the clinically unaffected eye but also showed that, this modality, utilizing CVI and TI together with choroidal thickness measurements, can be used as a readily available, noninvasive first-line followup method for evaluating occlusion of fistulas by endovascular treatment or spontaneous resolution.

Analysis of the Peripapillary Choroidal Vascular Characteristics in Papilledema Associated with Pseudotumor Cerebri

SIGNIFICANCE

Choroidal vascularity index measured by image binarization method from peripapillary optical coherence tomography sections has been found significantly lower in papilledema patients than healthy controls.

PURPOSE

The purpose of this study was to compare peripapillary choroidal parameters in papilledema patients with control subjects.

METHODS

Peripapillary spectral domain optical coherence tomography scans of 34 patients with papilledema and 34 healthy controls are acquired for the study. Images are binarized with the ImageJ software (National Institutes of Health, Bethesda, MD) to calculate total choroidal area, stromal area, luminal area, and choroidal vascularity index.

RESULTS

Total choroidal area, luminal area, and choroidal vascularity were significantly lower in papilledema patients compared with healthy controls on right (1.343 ± 0.286 vs. 1.694 ± 0.344, P < .001; 0.880 ± 0.209 vs. 1.167 ± 0.255, P < .001; 65.28 ± 2.99% vs. 68.68 ± 2.81%, P < .001, respectively) and left eyes (1.376 ± 0.308 vs. 1.647 ± 0.339, P < .001; 0.899 ± 0.231 vs. 1.134 ± 0.237, P < .001; 64.92 ± 3.44 vs. 68.84 ± 3.23, P < .001, respectively). No difference was found between active and remitted stages of papilledema in terms of choroidal parameters.

CONCLUSIONS

Peripapillary total choroidal area, luminal area, and choroidal vascularity index are significantly reduced in patients with papilledema. These parameters might be beneficial tools for evaluating choroidal vascularity in papilledema quantitatively and differential diagnosis for optic disc edema.

Venous overload choroidopathy: A hypothetical framework for central serous chorioretinopathy and allied disorders

In central serous chorioretinopathy (CSC), the macula is detached because of fluid leakage at the level of the retinal pigment epithelium. The fluid appears to originate from choroidal vascular hyperpermeability, but the etiology for the fluid is controversial. The choroidal vascular findings as elucidated by recent optical coherence tomography (OCT) and wide-field indocyanine green (ICG) angiographic evaluation show eyes with CSC have many of the same venous patterns that are found in eyes following occlusion of the vortex veins or carotid cavernous sinus fistulas (CCSF). The eyes show delayed choroidal filling, dilated veins, intervortex venous anastomoses, and choroidal vascular hyperpermeability. While patients with occlusion of the vortex veins or CCSF have extraocular abnormalities accounting for the venous outflow problems, eyes with CSC appear to have venous outflow abnormalities as an intrinsic phenomenon. Control of venous outflow from the eye involves a Starling resistor effect, which appears to be abnormal in CSC. Similar choroidal vascular abnormalities have been found in peripapillary pachychoroid syndrome. However, peripapillary pachychoroid syndrome has intervortex venous anastomoses located in the peripapillary region while in CSC these are seen to be located in the macular region. Spaceflight associated neuro-ocular syndrome appears to share many of the pathophysiologic problems of abnormal venous outflow from the choroid along with a host of associated abnormalities. These diseases vary according to their underlying etiologies but are linked by the venous decompensation in the choroid that leads to significant vision loss. Choroidal venous overload provides a unifying concept and theory for an improved understanding of the pathophysiology and classification of a group of diseases to a greater extent than previous proposals.

Choroidal vascularity index in thyroid-associated ophthalmopathy: a cross-sectional study

Background

Hemodynamic changes have been observed in patients with Graves’ disease. The aim of our study was to evaluate choroidal vascular change using the choroidal vascularity index (CVI) in patients with thyroid-associated ophthalmopathy (TAO).

Methods

In this cross-sectional observational study, 40 patients affected by TAO were recruited. Forty healthy individuals, matched for age and sex, served as controls. Foveal enhanced-depth imaging optical coherence tomography scans were obtained from all participants. Images were binarized using the ImageJ software and luminal area (LA) and total choroidal area (TCA) were measured. CVI was calculated as the proportion of LA to TCA. The relation between CVI or subfoveal choroidal thickness (SFCT) and clinical activity score, exophthalmometric value, diplopia status, gender, and age was evaluated.

Results

CVI was significantly higher in patients with TAO (P = 0.004). No significant difference was observed in SFCT (P = 0.200) and TCA (P = 0.153) comparing TAO patients and healthy controls. LA was significantly higher in TAO group (P = 0.045). On multiple regression analysis, CVI was associated with TCA (P = 0.043). No association was found between SFCT or CVI and TCA, clinical activity score, exophthalmometric value, Inami value, diplopia status, gender or age (P > 0.05).

Conclusions

This is the first study that has demonstrated an increase in CVI in eyes with TAO compared with healthy controls and has assessed its association with clinical features.

Observation of fundus and optical coherence tomography angiography manifestations in carotid cavernous fistula patients

PURPOSE

This study aimed to investigate fundus and optical coherence tomography angiography (angio-OCT) manifestations in carotid cavernous fistula (CCF) patients.

METHODS

Nine eyes of 7 CCF patients diagnosed with digital subtraction angiography (DSA) were included in this study. Best-corrected visual acuity (BCVA), intraocular pressure (IOP), slit lamp, fundus, spectral-domain optical coherence tomography (SD-OCT), and optical coherence tomography angiography (angio-OCT) examination in the CCF patients and 10 normal controls were conducted. Subfoveal choroidal thickness (SFCT) and macular vascular density (VD) were measured and compared with the control group. SFCT and VD were also compared before and after embolization therapy.

RESULTS

Two male and 5 female CCF patients were included. The average age was 59.7 ±10.0 (years). Embolization therapy was conducted in 3 patients. Fundus manifestations included disc oedema and exudation, retinal venular dilation, and retinal haemorrhage. B-scan OCT examination revealed retinal and choroidal undulations, retinal-choroidal thickness, retinal cystoid oedema, and subretinal fluid. The SFCT of the affected eyes was thicker than that of the control group (412.3 ± 123.7 μm vs. 272.9 ± 62.9 μm; P = 0.006). Macular superficial capillary plexus (SCP) VD in affected eyes was lower than that in the control eyes (50.1 ±2.3 % vs. 52.7 ± 1.7 % ; P = 0.014). The SFCT was reduced, and the vessel density in the SCP was increased after embolization therapy.

CONCLUSION

We demonstrated decreased VD in CCF patients with specific fundus and OCT manifestations. The pathological changes were immediately reduced after embolization therapy. This preliminary observation provides a supplemental method for the diagnosis and pathophysiological examination of CCF patients.

Choroidal Vascularity Index: An In-Depth Analysis of This Novel Optical Coherence Tomography Parameter

Remarkable improvements in optical coherence tomography (OCT) technology have resulted in highly sophisticated, noninvasive machines allowing detailed and advanced morphological evaluation of all retinal and choroidal layers. Postproduction semiautomated imaging analysis with dedicated public-domain software allows precise quantitative analysis of binarized OCT images. In this regard, the choroidal vascularity index (CVI) is emerging as a new imaging tool for the measurement and analysis of the choroidal vascular system by quantifying both luminal and stromal choroidal components. Numerous reports have been published so far regarding CVI and its potential applications in healthy eyes as well as in the evaluation and management of several chorioretinal diseases. Current literature suggests that CVI has a lesser variability and is influenced by fewer physiologic factors as compared to choroidal thickness. It can be considered a relatively stable parameter for evaluating the changes in the choroidal vasculature. In this review, the principles and the applications of this advanced imaging modality for studying and understanding the contributing role of choroid in retinal and optic nerve diseases are discussed. Potential advances that may allow the widespread adoption of this tool in the routine clinical practice are also presented.

Exploring choroidal angioarchitecture in health and disease using choroidal vascularity index

The choroid is one of the most vascularized structures of the human body and plays an irreplaceable role in nourishing photoreceptors. As such, choroidal dysfunction is implicated in a multitude of ocular diseases. Studying the choroid can lead to a better understanding of disease pathogenesis, progression and discovery of novel management strategies. However, current research has produced inconsistent findings, partly due to the physical inaccessibility of the choroid and the lack of reliable biomarkers. With the advancements in optical coherence tomography technology, our group has developed a novel quantitative imaging biomarker known as the choroidal vascularity index (CVI), defined as the ratio of vascular area to the total choroidal area. CVI is a potential tool in establishing early diagnoses, monitoring disease progression and prognosticating patients. CVI has been reported in existing literature as a robust marker in numerous retinal and choroidal diseases. In this review, we will discuss the current role of CVI with reference to existing literature, and make postulations about its potential and future applications.