Cibele Figueira Carvalho

Princípios físicos do Doppler em ultra-sonografia

Doppler ultrasonography is a relatively new diagnostic tool in veterinary medicine that provides real time details about vascular architecture and hemodynamic aspects of examinated blood vessels in several internal organs. Doppler can identify the presence, direction and type of blood flow. This literature review provides information about the physical principles of Doppler ultrasonography. The enlargement of expertise about this technology lead to a better comprehension of its use and limitations as a diagnostic technique, which already becomes usual in veterinary medicine of small animals.

Normal Doppler velocimetry of renal vasculature in Persian cats

Renal diseases are common in older cats. Decreased renal blood flow may be the first sign of dysfunction and can be evaluated by Doppler ultrasound. But previous studies suggest that the resistive index (RI) has a low sensitivity for detecting renal disease. Doppler waveforms of renal and intrarenal arteries demonstrate decreased blood flow before there are any changes in the RI. The purpose of this study was to evaluate the normal Doppler flowmetrics parameters of renal arteries (RAs), interlobar arteries (IAs) and abdominal aorta (AO) in adult healthy, Persian cats. Twenty-five Persian cats (13 females and 12 males with mean age of 30 months and an age range 12–60 months) with normal clinical examinations and biochemical tests and normal systemic blood pressure were given B-mode ultrasonographies in order to exclude all nephropathies, including polycystic kidney disease. All measurements were performed on both kidneys. Both kidneys (n=50) were examined by color mapping of the renal vasculature. Pulsed Doppler was used to examine both RAs, the IAs at cranial, middle and caudal sites, and the AO. The RI was calculated for all of the vessels. Early systolic acceleration (ESA) of RA and IA was obtained with Doppler spectral analysis. Furthermore, the ratio indices between RA/AO, and IA/RA velocities were calculated. The mean values of peak systolic velocity (PSV) and the diameter for AO were 53.17±13.46 cm/s and 0.38±0.08 cm, respectively. The mean RA diameter for all 50 kidneys was 0.15±0.02 cm. Considering the velocimetric values in both RAs, the mean PSV and RI that were obtained were 41.17±9.40 cm/s and 0.54±0.07. The RA had a mean ESA of 1.12±1.14 m/s2 and the calculated upper limit of the reference value was 3.40 m/s2. The mean renal-aortic ratio was 0.828±0.296. The IA showed PSV and RI values of 32.16±9.33 cm/s and 0.52±0.06, respectively. The mean ESA of all IAs was 0.73±0.61 m/s2. The calculated upper limit of the reference value was 2.0 m/s2. The mean renal-interlobar artery ratio was 1.45±0.57. The RI values obtained in this study were similar to values reported in the literature. Some conditions that lead to a decrease in compliance and to an increase in vascular resistance can affect the Doppler spectral waveforms without changes in RI. To our knowledge, there are no studies that were directed toward to the normal ESA values of the renal vasculature in Persian cats. This study introduced a new ratio between the PSV of the RA and the IA. This index was developed based on the well-known effects of Doppler on the detection of stenosis, regardless of the cause. Further studies are necessary to verify the hemodynamic behavior of this index under pathological conditions in cats as well as the effect of aging, nephropathies and systemic pressure on Doppler velocimetric parameters.

Ultra-sonografia transcraniana em cães com distúrbios neurológicos de origem central

In this work, 55 dogs with neurologycal disorder were examined and central neurological affections were detected by transcranial ultrasonography (TCUS). They were classifyed in hydrocephaly, lissencephaly, focal and difuse parenchimal disorders, and none changes. From the examinated dogs, 52.9% presented diagnosis compatible with hydrocephaly, being 55.1% female and 51.7% younger than 2 year-old. Fifteen dogs (27.3%) presented focal lesions, 7.2% diffuse lesions, 7.2% images that suggested lissencephaly, and in 5.4% no changes were detected by TCUS. It was concluded that hydrocephaly was the most frequent central neurologycal disorder and TCUS is a valuable alternative to be used in clinical routine as a tool of diagnostic to detect morphological and structural cerebral disorders in dogs.

Parâmetros Doppler velocimétricos das artérias renais e da aorta abdominal em gatos da raça persa

Prospective study was made performing Doppler ultrasonographic exams of fifty kidneys belonging to Persian adult cats. The animals were classified as healthy by laboratorial exams and measurement of arterial systolic pressure. Maximal systolic blood flow velocity (VPS), minimal diastolic blood flow velocity (VDF) and resistivity index (IR) of renal arteries (AR) and aorta (AO) of each animal were evaluated. The results are: left renal artery VPS 40.96±9.08cm s-1 and IR 0.55±0.07; right artery VPS 41.39±9.89cm s-1 and IR 0.52±0.07. It was not observed any statistical significant difference among the sides. Considering both renal arteries it was calculated VPS 41.17±9.40cm s-1 and IR 0.53±0.07. Renal arterial diameter was 0.15±0.02cm. The aorta VPS obtained was 53.17±13.46cm s-1 and the diameter was 0.38±0.04cm. Correlation velocities of renal artery and aorta resuled in a relation 0.38 as minimal and 1.52 as maximal, with 0.82±0.30.

Morfologia duplex Doppler dos principais vasos sanguíneos abdominais em pequenos animais

Duplex Doppler ultrasonography is able to provide real time anatomic and hemodynamic information. The complete knowledge of the normal Doppler spectrum of each blood vessel is important to their identification, since each vessel has a specific Doppler sign. Recognizing the changes in the morphology of Doppler spectrum is only possible based on previous knowledge of its variations. This is a literature review about Doppler pattern of the major abdominal blood vessels in small animals.

Transcranial duplex doppler ultrasonography in dogs with hydrocephalus

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.

Dopplervelocimetric evaluation of portal vein as a diagnostic tool for portosystemic shunt diagnosis in dogs

The objective of this research was to verify if the study of portal hemodynamic parameters through duplex Doppler ultrasonography (DUS) is able to help to detect portosystemic shunt (PSS) and the shunted vessel origin. It was detected PSS in 20 dogs by abdominal DUS and confirmed at surgery or necropsy from March of 2004 until March 2007. Main ultrasonographic findings were: identification of a tortuous vessel shunting portal flow being: portocaval shunt (16/20 or 80%), esplenocaval shunt (2/20 or 10%), gastrocaval shunt (1/20 or 5%), portoazigo shunt (1/20 or 5%); 2) elevated portal flow velocity before shunt (17/20 or 81%), 3) lower portal flow velocity after shunt (17/20 or 81%), 4) turbulence in the caudal vena cava (10/20 or 47,5%) and 5) reduced liver size (15/20 or 71%). The others ultrasonographic findings associated with clinical records were similar to that described in literature. With this work we could conclude that hemodynamic assessment of portal vein with DUS may be a useful tool for PSS diagnosis and to detect the shunted vessel origin.

Uso do ultra-som dúplex Doppler no diagnóstico de shunt portossistêmico em gatos

Abdominal duplex Doppler ultrasonography was used in two cats with hepatic encephalopathy clinical signs. The main ultrasonographic findings were: identification of a tortuous strange vessel shunting portal flow; elevated portal flow velocity; turbulence in the caudal vena cava, and reduced size of liver and hepatic portal branches. Necropsy findings were similar to that found at ultrasonographic and clinical exams. It is concluded that portosystemic shunt diagnosis may be a real hypothesis to be considered in cats with clinical signs of hepatic encephalopathy.

Association of Doppler Wave Pattern of Hepatic Veins and Fatty Liver Disease Degree

The objective of this study was to document the progressive effects of fatty infiltration of the liver on hepatic veins (HVs) by measuring Doppler waveforms in groups of rats and dogs. All of the groups underwent hepatic B-mode and duplex Doppler sonography. B-mode fatty infiltration was classified into four degrees corresponding to increasing grades of hepatic echogenicity for all groups: (0) absent, (1) mild, (2) moderate and (3) severe fatty infiltration. Histograms were obtained in all dogs to standardise each grade of hepatic echogenicity and an increasing distribution of grey-levels was found according to the grade of fatty infiltration of the liver in obese dogs. The Doppler sonography spectra of HVs were classified into three groups: normal or triphasic waveforms, biphasic waveforms, and monophasic or flat waveforms. Obese dogs (60%) and rats (100%) with fatty infiltration of the liver presented biphasic or flat right HV Doppler waveforms more often than control dogs and rats, and these differences were statistically significant (p = 0.002 for dogs and p = 0.0028 for rats). None of the control dogs and rats had monophasic waveforms. These findings suggest there is an association between wave form pattern of hepatic veins and the degree of fatty liver disease.

Acoustic radiation force impulse (ARFI) elastography of testicular disorders in dogs: preliminary results.

The aim of this study was to describe the use of acoustic radiation force impulse (ARFI) elastography in the evaluation of testicular disorders in dogs. Eighteen dogs with testicular disorders (thirty-six testicles) were assessed. Echotexture, size, contours and margins of testes were analysed by ultrasonography. Deformities and tissue stiffness (greyscale and homogenous or heterogeneous) were evaluated by qualitative elastography and shear velocity was determined quantitatively. Subsequent to orchiectomy, testicular samples were collected for histopathology analysis and thirty-six disorders were identified. Qualitative elastography revealed that normal healthy testicular tissues were homogenous and not pliable while the affected testicles had alterations in tissue stiffness and homogeneity. The values obtained for quantitative elastography of the testicular tissues were: normal/healthy - 1.30±0.12 m/s; degenerated - 0.97±0.08 m/s; atrophied - 2.00±0.35 m/s; hypoplastic - 0.82±0.2 m/s; cystic - 1.32±0.18 m/s; orchitis - 2.68±0.42 m/s; interstitial cell tumours - 3.32±0.65 m/s; sertolioma - 2.99±0.07 m/s and leydigoma - 2.73±0.37. ARFI elastography of abnormal testes proved to be an applicable and complementary technique in the diagnosis of testicular disease in dogs.