Сolor Doppler Imaging in Eye Hemodynamics Evaluation in Syndrome of Thrombotic Microangiopathy

Purpose.To assess the state of blood flow in retrobulbar vessels using the method of color Doppler imaging in thrombotic microangiopathy (TMA) associated with atypical hemolytic uremic syndrome (aHUS), malignant hypertension (MH) and catastrophic antiphospholipid syndrome (CAPS).Methods. The study involved 16 patients aged from 18 to 43 years with TMA associated with aHUS (13 patients), MH (2 patients) and CAPS (1 patient). All patients underwent a study of the state of blood flow in the vessels of the retrobulbar space by color Doppler imaging using a multifunctional ultrasonic diagnostic device Voluson 730 Pro and Voluson E8. The spectrum of blood flow in the ophthalmic artery (OA), central retinal artery (CRA), central retinal vein (CRV), in the medial and lateral short posterior ciliary arteries (SPCA) was recorded and the following parameters were determined: maximum systolic velocity (Vsyst), final diastolic velocity (Vdiast), peripheral resistance index (RI), pulsation index (PI).Results. The analysis of the Doppler blood flow spectrum in all patients with TMA syndrome revealed a decrease in Vsyst in the vessels of the retrobulbar space, more pronounced in the CRA, with an increase in the venous component of the Doppler spectrum. In patients with TMA associated with aHUS and MH Vdiast in the studied vessels were in normal limits or increased, RI and PI were reduced. In aHUS a statistically significant correlation was found between Vdiast in OA and the level of haptoglobin in blood serum, which is a classic marker of intravascular hemolysis.Conclusion. Color Doppler imaging of retrobulbar vessels is an important method for the diagnosis of ocular hemodynamics disorders in the syndrome of TMA. All patients with TMA syndrome are characterized with a decrease in the systolic component of the Doppler spectrum of blood flow in the vessels of the retrobulbar space, especially in the CRA, with an increase in the venous component. With aHUS and MH diastolic blood flow in the retrobulbar vessels corresponds to the norm or increases, RI and PI decrease. In TMA associated with aHUS, the final diastolic velocity of blood flow in OA depends on the level of microvascular hemolysis.

Color Doppler imaging features in patients presenting central retinal artery occlusion with and without giant cell arteritis

Introduction. Central retinal artery obstruction (CRAO) represents an abrupt diminution of blood flow through the CRA that is severe enough to cause ischemia of the inner retina with permanent unilateral visual loss. We presented the role of color Doppler imaging (CDI) of orbital vessels and of extracranial duplex sonography (EDS) in the etiological diagnosis of CRAO in two patients with clinical suspicion of unilateral CRAO. Case report. Patients were examined following the protocol which included CDI of orbital vessels and EDS. Both patients had no emboli visible on ophthalmoscopy. The B-scan ultrasound evaluation of the first patient found a small round, moderately reflective echo within the right optic nerve, 1.5 mm behind the optic disc (emboli of cholesterol). CDI of retrobulbar vessels revealed the normal right ophthalmic artery (OA) hemodynamic parameters, but the first patient had no arterial flow signal on CDI at the distance of 1.5 mm behind the right optic disc. In contrast, the left eye had the normal aspect on CDI of retrobulbar vessels. The right internal carotid artery EDS identified a severe stenosis at its origin as CRA?s emboli source. The second patient had characteristic CDI findings for giant cell arteritis (GCA) with eye involvement: severe diminished blood flow velocities, especially end-diastolic velocities, in both CRAs. Less abnormalities were observed in the posterior ciliary arteries, and in the ophthalmic arteries. The second patient had no systemic symptoms or signs of GCA. Conclusion. In the presented cases, the ultrasound investigation enabled prompt differentiation between central retinal artery occlusion of embolic mechanism and CRAO caused by GCA.

Correlation between ocular pulse amplitude measured by dynamic contour tonometer and colour doppler flow imaging of the arteric retrobulbar vessels

Introduction. An altered perfusion of the optic nerve head has been proposed as a pathogenic factor in glaucoma. Objective. The aim of this study was to evaluate the correlation between ocular pulse amplitude (OPA), measured by Dynamic contour tonometer (DCT) and colour Doppler imaging (CDI) of the arteric retro- bulbar vessels. Methods. Twenty patients older than 50 years were examined, and divided into two equal groups. The first group comprised of patients with normal tension glaucoma treated with topical antiglaucomatous therapy, and the second group included patients with ocular hypertension and glaucoma suspicious without any antiglaucomatous therapy. Ocular pulse amplitude (OPA) was measured with DCT. CDI was also performed. We measured haemodynamic parameters of the internal carotid artery (ICA), ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary arteries (PCA). Peak systolic (PSV), end- diastolic (EDV) velocities were measured, and resistance index (RI) and pulsatility index (PI) were calculated. Results Correlation with OPA showed indirect servitude in the RI of the ICA, RI and PI of the CRA, in the first group; and in the PSV and EDV of the ICA, in the RI and PI of the OA, EDV and RI of the CRA, and RI of the PCA, in the second group Conclusion. Increase of OPA was mostly followed by the increase of the parameters (PSV, EDV, RI, and PI) of the arteric retrobulbar vessels in the first group; in the second group, increase of OPA was in almost 50% of parameters followed by their decrease.

Color Doppler Imaging and Ocular Pulse Amplitude in Glaucomatous and Healthy Eyes

Purpose To determine factors influencing color Doppler imaging (CDI) measurements, to compare retrobulbar flow velocities between patients with glaucoma and healthy controls, and to describe the correlation between CDI and ocular pulse amplitude (OPA). Methods Patients with normal tension (n=28) or primary open angle glaucoma (n=19) and healthy controls (n=22) underwent CDI and OPA measurements. Intraocular pressure, corneal thickness, blood pressure, and heart rate were also measured. Spearman correlations were used to explore relations among these variables. A regression model for repeated measures was applied to compare between diagnostic groups the flow velocity indices in the retrobulbar vessels. Results Retrobulbar diastolic blood flow velocities correlated with diastolic blood pressure and perfusion pressure (range of Spearman rho [ρ] coefficients=0.25–0.28; P=0.044–0.013 for the different vessels). Corneal thickness showed a positive correlation with systolic and diastolic flow velocities in the central retinal artery (ρ=0.29 and 0.31; P=0.017 and 0.011 for peak systolic and end diastolic velocity, respectively). Systolic and diastolic blood flow velocities were reduced in the retrobulbar vessels of patients with normal tension glaucoma (P=0.0004) as well as primary open angle glaucoma (P=0.003) compared to healthy controls. A correlation was found between OPA and the resistive index in the retrobulbar vessels of the healthy controls (range ρ=0.42–0.53; P=0.059–0.014). Conclusions Retrobulbar blood flow velocities are reduced in patients with primary open angle glaucoma and normal tension glaucoma. Blood pressure and corneal thickness may influence CDI measurements. OPA correlates with the resistive index in CDI.