Basic Ultrasound Physics, Doppler Ultrasound, and Hemodynamic Assessment

Transcranial duplex Doppler ultrasound was performed in 32 conscious dogs presenting ventriculomegaly detected in B-mode, obtaining measures of lateral ventricles and resistance parameters of main cerebral arteries before and after 30 days of clinical treatment. The animals were distributed divided in two groups: group 1, dogs that presented remission or decrease of the neurological signs of the disease after clinical therapy; and group 2, dogs that displayed worsening of the neurological signs or clinical stability. The data were all presented in tables and were submitted to paired t test and to logistic regression models to evaluate the influence of the RI reduction on both groups. There was no significant influence of the variables in the B-mode. After the treatment, the mean resistive index (RI) was significantly lower for the group that presented clinical improvement. There was no significant difference of the mean RI reduction for the same artery when the right and left sides were compared. It could be concluded that transcranial duplex Doppler ultrasound is a method of cerebral hemodynamic assessment able to monitor more precisely the treatment of hydrocephalus in dogs and verify the responses.

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Biometric, B-mode and color Doppler ultrasound assessment of eyes in healthy dogs

Pesquisa Veterinária Brasileira ◽

10.1590/1678-5150-pvb-5242 ◽

2018 ◽

Vol 38 (3) ◽

pp. 565-571

Author(s):

Elzivânia G. Silva ◽

Gerson T. Pessoa ◽

Laecio S. Moura ◽

Porfírio C. Guerra ◽

Renan P.S. Rodrigues ◽

...

Keyword(s):

Optic Nerve ◽

Doppler Ultrasound ◽

Statistical Difference ◽

Ophthalmic Artery ◽

Anterior Chamber Depth ◽

Pulsed Doppler ◽

Resistivity Index ◽

Hemodynamic Assessment ◽

The Mean ◽

The Right

ABSTRACT: B-scan ultrasonography is an important diagnostic tool that allows characterization of internal organ anatomy and, when complemented by Doppler ultrasound, allows vascular hemodynamic assessment, increasing the diagnostic accuracy. Thus, the aim of the present study was the B-scan ultrasound characterization and measurement of the eyeball segments and assessment of the external ophthalmic artery by color and pulsed Doppler. Sixty eyeballs were assessed from 30 dogs of different breeds using an 8.5MHz microconvex transductor. First, biometry was performed by B-scan of the following segments: axial length (M1), anterior chamber depth (M2), lens thickness (M3), lens length (M4), vitreous chamber depth (M5), optical disc length (M6) and optic nerve diameter (M7). Colored Doppler identified the external ophthalmic article and pulsed Doppler assessed its flow, and the following were measured: systolic peak velocity (VPS), final diastolic velocity (VDF), resistivity index (IR) and pulse index (IP). No statistical difference was observed for the biometric values of the eye segments between the right and left eyes (p>0.05). The vitreous chamber depth (M5) was shown to be the biometric variable with greatest bilateral symmetry, varying from 0.79 to 0.87cm and 0.78 to 0.86cm for the right and left eye, respectively. The ophthalmic artery was visualized over the optic nerve towards the eyeball, with flow stained red. There was no significant statistical difference between the Doppler velocimetric values for the ophthalmic artery between the right and left eye of the animals assessed (p>0.05). The mean resistivity index (RI) showed average values equal to 0.63±0.03, bilaterally. The mean base velocity was 17.50cm/s and 18.18cm/s at the systolic peak and 6.21cm/s and 6.68cm/s at the end of the diastole, for the right and left eyes respectively. The anatomic, biometric and hemodynamic characterization using the ultrasound B-scan and the Doppler modalities permitted the ultrasonographic and Doppler velocimetric assessment of the eyeball components in dogs of different breeds, and it can be used in ophthalmic clinical routine to identify eye pathologies.

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