Ultrasound imaging velocimetry of the human vitreous.

Tommaso Rossi, Giorgio Querzoli, Giacomo Pasqualitto, Mario Iossa, Luca Placentino, Rodolfo Repetto, Alessandro Stocchino, Guido Ripandelli

Ospedale Oftalmico di Roma, Rome, Italy. tommaso.rossi@usa.net

Experimental eye research 2012 Jun

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Knowledge of vitreous motion in response to saccades is a prerequisite for understanding vitreous rheology. Purpose of present paper is to introduce Ultrasound Image Velocimetry of the human eye, measure scleral and vitreous velocity fields and test the reproducibility of the proposed technique. Twelve patients with varying diagnosis underwent Ocular Dynamic Ultrasound; scleral angular velocity (V(S)) was measured by 2 different operators and reproducibility calculated. Squared velocity of the vitreous (E), which is representative of kinetic energy per unit mass, was computed from velocity. The time evolution of the energy of the vitreous was described by its spatial average (E(S)), whereas spatial distribution was described by its time average (E(T)). Peak and average E(S), the ratio K(p) of the peak of the spatially averaged kinetic energy per unit mass to the maximum squared scleral angular velocity, vitreous motion onset time (T(O)) and vitreous motion decay time (T(D)) were also defined. Inter-operator reproducibility coefficient was 0.043 and correlation between operators was significant. V(S), peak and average E(S), K(p) ratio and T(D) differed among patients but not among operators. V(S) correlated with E(S) and T(D). E(S) and T(D) but not V(S), were significantly different in patients with Posterior Vitreous Detachment. Patients with retinal detachment showed significantly higher V(S) and E(S). K(p) was inversely correlated to age and refraction. Measures proved accurate and reproducible. E is related to V(S), retinal traction and mechanical stimulation. Identified variables varied with age, refraction pathologic conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Citation

Tommaso Rossi, Giorgio Querzoli, Giacomo Pasqualitto, Mario Iossa, Luca Placentino, Rodolfo Repetto, Alessandro Stocchino, Guido Ripandelli. Ultrasound imaging velocimetry of the human vitreous. Experimental eye research. 2012 Jun;99:98-104