Contrast-enhanced ultrasonography in the differentiation of retinal detachment and vitreous membrane in dogs and cats.

OBJECTIVES: To evaluate contrast-enhanced ultrasonography (CEU) and colour Doppler imaging (CDI) for detection of persistent vascularisation in retinal detachment. METHODS: In 22 eyes, retinal detachment (n=13) and vitreous membranes (n=9) were confirmed by ophthalmological examination, during cataract surgery, by histopathology or after vitreoretinal surgery. Tentative diagnosis of retinal detachment or vitreous membrane was made using grey-scale B-mode ultrasonography. Assessment of retinal detachment was based on the presence or absence of vascularisation in the membranous structure using CDI and CEU. RESULTS: Sensitivity, specificity, positive-predictive value and negative-predictive value of grey-scale ultrasonography in differentiating retinal detachment from vitreous membrane were 92·3%, 66·6%, 80% and 85·7%. In 91% of eyes, colour Doppler assessment was unsuccessful due to the movement of the eye. Persistent vascularisation was demonstrated in all cases of retinal detachments with CEU. CEU was 100% accurate for detection and differentiation between retinal detachment and vitreous membrane. CLINICAL SIGNIFICANCE: CEU is a useful clinical tool for the diagnosis of retinal detachment and vitreous membrane in dogs and cats.

Ultrasonographic evaluation of vitreous degeneration in normal dogs.

Vitreous degeneration is common in dogs and may be associated with cataract formation. Vitreous degeneration may be identified using B-mode ultrasonography and appears as multiple, small, motile, point-like echoes within the vitreous cavity. In humans, vitreous degeneration has also been observed in normal aging eyes but the incidence of vitreous degeneration in dogs without cataract has not previously been documented. The purpose of this study was to describe the ultrasonographic appearance of vitreous degeneration and to investigate its incidence in a population of dogs without cataract or other apparent eye disease. The eyes of 62 dogs were evaluated as part of a prospective study. All dogs underwent ophthalmological and ultrasonographic examinations and vitreal changes were graded on ultrasonography using a predetermined grading scheme. Vitreous degeneration was found in 20% (23/114) of the eyes on ultrasonographic examination but in only 8% (9/114) of eyes on direct ophthalmoscopy. Sensitivity and specificity of ophthalmoscopy using ultrasonography as a gold standard were respectively, 39% and 100%. Vitreal syneresis and asteroid hyalosis could be distinguished according to their ultrasonographic characteristics. The probability of having vitreous degeneration increased with the age of the dog (odds ratio = 6.7 for dogs of 7 + years compared with 0-6 years) and also increased in females compared with males (odds ratio = 3.6). Vitreous degeneration, especially mild vitreal syneresis, is not uncommon in normal dogs; it was shown to be an age-related condition and its significance should not be overinterpreted on ocular ultrasonography.