Review: Current status of corpus luteum assessment by Doppler ultrasonography to diagnose non-pregnancy and select embryo recipients in cattle.

A number of potentials uses of Doppler ultrasonography have been explored in the last decades, both as research tools in reproductive physiology investigations and for the reproductive management of farm animals. The objective of this review was to address some of the recent strategies developed in fixed-time reproductive programs and resynchronization of ovulation in cattle, based on the evaluation of corpus luteum function by color-Doppler ultrasound imaging. Recent studies in dairy and beef cattle pointed out to a high accuracy when Doppler ultrasonography is used to assess the functionality of the corpus luteum and identify non-pregnant females at 20-24 days after breeding. Therefore, super-early resynchronization programs starting in the second week after timed-artificial insemination or embryo transfer have been developed and are being implemented in commercial assisted reproduction programs; thus, anticipating conception with proven semen or genetically superior embryos. In addition, assessment of corpus luteum blood perfusion can be used for identifying high fertility embryo recipients in fixed-time embryo transfer programs.

Understanding the barriers to blood pressure assessment in cats.

OBJECTIVES: A questionnaire was designed to survey veterinarians and veterinary nurses/technicians on blood pressure (BP) assessment in cats, including ocular examination, encompassing current methodology, indications, uptake and barriers. METHODS: An online questionnaire was produced and promoted to more than 2000 veterinary professionals, of whom 545 answered all questions and 85 answered most questions. RESULTS: Of the participants, 572 (90.8%) were based in the UK and almost all (n = 613, 97.3%) had access to a BP monitor. Of those that had a monitor, most (n = 550, 88.4%) participants had access to a Doppler monitor; 367 (59.0%) participants had access to multiparameter monitors; fewer (n = 202, 32.5%) had access to oscillometric BP monitors. Where applicable, Doppler monitors were most commonly chosen for conscious cat measurements (n = 337, 72.2%) due to the greater 'trust' and 'reliability' of these compared with oscillometric machines. Conscious BP measurement typically involved two members of staff (n = 391, 62.9%). Only 156 (29.1%) participants recommended BP assessment at least several times a week in their interactions with cat owners. BP assessment was routinely recommended in cats with ocular target organ damage (n = 365, 87.7%), chronic kidney disease (n = 346, 78.6%), proteinuria (n = 255, 63.0%) and hyperthyroidism (n = 266, 60.9%). Common equipment-related barriers included 'cuff frustration' and difficulties hearing the pulse signal for Doppler users (72.2% and 71.6%, respectively), and oscillometric machines failing to give a reading at least some of the time (52.8%). Situational hypertension concerns affected many (n = 507, 92.0%), as did lack of time to do the procedure (n = 402, 73.0%). Significant owner barriers included difficulties persuading the owner to bring their cat in for BP checks (n = 475, 86.2%) and concerns over costs (n = 445, 80.8%). Most participants had access to a direct ophthalmoscope (n = 527, 96.5%); however, 399 (73.1%) reported that they struggled to interpret ocular findings. CONCLUSIONS AND RELEVANCE: Significant barriers exist to successful BP assessment in cats. Education and support of clinics should focus on improving confidence with equipment and eye examination.

Assessment of the accuracy of testicular dysfunction detection in male donkey (Equus asinus) with the aid of colour-spectral Doppler in relation to plasma testosterone and serum nitric oxide levels.

This study aimed to determine the usefulness of colour and pulsed Doppler modes for the accurate diagnosis of donkeys suffering from subfertility to determine whether testicular vascularity assessment could be an indicator for sperm functionality. The study sample was composed of 10 male donkeys with normospermia (control group) and 10 donkeys with hypospermia. Animals underwent scrotal circumference measurement, testicular Doppler examination, seminal evaluation, blood sampling and hormonal assay. Semen volume and concentration were significantly (p ≤ .05) lower in the subfertile group (30.25 ± 1.22 ml and 89.44 ± 2.55 × 106 /ml) as compared with the control group (82.76 ± 1.65 ml and 452.78 ± 1.25 × 106 /ml), and total sperm/ejaculation was significantly (p ≤ .05) higher in the normal donkeys (28.30 ± 2.32 × 109 /total ejaculated) as compared with the subfertile group. Intratesticular coloured area showed a marked decline in the hypospermic males. There was no significant difference between the two groups in testosterone level, although the normal group showed an increase in nitric oxide metabolites. Both Doppler indices of the three branches of the testicular artery were elevated significantly (p ≤ .05) in abnormal donkeys, whereas Doppler peak systolic and end-diastolic velocities were increased in the normal group. Male donkeys with subfertility demonstrated lower arterial vascularity parameters in the form of intratesticular coloured area and blood flow rate; therefore, the most optimal parameters for differentiating subfertile hypospermic from normospermic donkeys were found to be the two Doppler indices, velocities parameters, testicular blood flow rate and nitric oxide levels.

Non-invasive cardiovascular assessment of pregnancy in healthy female cats.

INTRODUCTION: The aim of this study was to evaluate cardiac morphology, indices of systolic and diastolic function, systolic blood pressure (SBP), and uterine artery resistance index (RI) during normal feline pregnancy. ANIMALS; MATERIALS AND METHODS: Twenty domestic short-hair pregnant queens, weighing 2.4-3.9 kg. Animals were assessed by two-dimensional, M-mode, and Doppler echocardiography, non-invasive SBP measurement, and uterine Doppler ultrasound every 10 days from mating to parturition. RESULTS: Interventricular septal thickness at end-diastole and end-systole, left ventricular internal dimension at end-diastole, left ventricular free wall thickness at end-diastole and end-systole, fractional shortening, stroke volume, cardiac output (CO), heart rate, and peak velocities of early and late diastolic transmitral flow increased during the second half of gestation, while SBP and RI decreased during the same period (p < 0.01). DISCUSSION AND CONCLUSIONS: Cardiac structure and function varied during normal pregnancy in these queens. Eccentric hypertrophy, increased indices of systolic function, and increased measurements of CO seem to be the consequences of the hemodynamic modifications occurring during pregnancy. The assessment of maternal cardiovascular function may prove a useful screening tool to detect pregnancy complications in feline species.

Assessment of a biofluid mechanics-based model for calculating portal pressure in canines.

BACKGROUND: Portal hypertension is a severe complication caused by various chronic liver diseases. The standard methods for detecting portal hypertension (hepatic venous pressure gradient and free portal pressure) are available in only a few hospitals due to their technical difficulty and invasiveness; thus, non-invasive measuring methods are needed. This study aimed to establish and assess a novel model to calculate free portal pressure based on biofluid mechanics. RESULT: Comparison of each dog's virtual and actual free portal pressure showed that a biofluid mechanics-based model could accurately predict free portal pressure (mean difference: -0.220, 95% CI: - 0.738 to 0.298; upper limit of agreement: 2.24, 95% CI: 1.34 to 3.14; lower limit of agreement: -2.68, 95% CI: - 3.58 to - 1.78; intraclass correlation coefficient: 0.98, 95% CI: 0.96 to 0.99; concordance correlation coefficient: 0.97, 95% CI: 0.93 to 0.99) and had a high AUC (0.984, 95% CI: 0.834 to 1.000), sensitivity (92.3, 95% CI: 64.0 to 99.8), specificity (91.7, 95% CI: 61.5 to 99.8), positive likelihood ratio (11.1, 95% CI: 1.7 to 72.8), and low negative likelihood ratio (0.08, 95% CI: 0.01 to 0.6) for detecting portal hypertension. CONCLUSIONS: Our study suggests that the biofluid mechanics-based model was able to accurately predict free portal pressure and detect portal hypertension in canines. With further research and validation, this model might be applicable for calculating human portal pressure, detecting portal hypertensive patients, and evaluating disease progression and treatment efficacy.

Ultrasound and clinical findings in the metacarpophalangeal joint assessment of show jumping horses in training.

BACKGROUND: Physical exercise is known to cause significant joint changes. Thus, monitoring joint behavior of athletic horses is essential in early disorders recognition, allowing the proper management. OBJECTIVES: The aims of this study were to determine the morphological patterns, physical examination characteristics and ultrasound findings of show jumping horses in training and to establish a score-based examination model for physical and ultrasound follow-ups of metacarpophalangeal joint changes in these animals. METHODS: A total of 52 metacarpophalangeal joints from 26 horses who were initially in the taming stage were evaluated, and the horses' athletic progression was monitored. The horses were evaluated by a physical examination and by B-mode and Doppler-mode ultrasound examinations, starting at time zero (T0), which occurred concomitantly with the beginning of training, and every 3 months thereafter for a follow-up period of 18 months. RESULTS: The standardized examination model revealed an increase in the maximum joint flexion angles and higher scores on the physical and ultrasound examinations after scoring was performed by predefined assessment tools, especially between 3 and 6 months of evaluation, which was immediately after the horses started more intense training. The lameness score and the ultrasound examination score were slightly higher at the end of the study. CONCLUSIONS: The observed results were probably caused by the implementation of a training regimen and joint adaptation to physical conditioning. The joints most likely undergo a pre-osteoarthritic period due to work overload, which can manifest in a consistent or adaptive manner, as observed during this study. Thus, continuous monitoring of young athlete horses by physical and ultrasound examinations that can be scored is essential.

Quantitative bidimentional and Doppler ultrasound assessment of the effect of a GnRH antagonist on canine prostatic hyperplasia.

The objectives of this article were: a) To describe the effect of a single administration of the third generation GnRH antagonist, acyline, on canine benign prostatic hyperplasia (BPH) b)To quantitatively compare parenchyma echogenicity, heterogeneity (SD echogenicity) and blood flow in hyperplastic and treated prostate glands. Seven mixed bred dogs, 11.14 ± 0.8 years of age, weighing 8.5 ± 1.4 (3.8-15.6) kg, with BPH were included in this study and administered acyline 330 mg/kg sc (day 0). Then the dogs were examined by B Mode and Doppler ultrasound on days 15, 30 and 60 after treatment. Parenchymal frozen images were digitally analyzed. On day -7, prostatic volume was 1.60-5.36 fold (volume ratio) enlarged in relation to the expected volume. Prostatic volume decreased up to a mean of -38.44% (P < 0.01; range -32.2 to -70.9%) on day 30 to gradually increase towards pretreatment values. A correlation between volume ratio and nadir treatment volume was also found (r = - 0.87; P < 0.05). Mean parenchyma echogenicity (P < 0.01) and heterogeneity (P < 0.01) diminished in all the post treatment evaluations. Pretreatment intraprostatic cysts disappeared at the time point of peak treatment effect. Prostatic arteries RI increased on day 30, being different from day -7 and also from day 60 values (P < 0.05). It was concluded that a single administration of a third generation GnRH antagonist safely decreased prostatic volume and parenchyma and blood flow abnormities associated with canine BPH during 30 days. Monthly administrations of this treatment could represent a rapid, efficient and safe therapeutic option for BPH.

B-mode and Doppler ultrasonography in the assessment of the common carotid arteries of equines and mules and the relation with body mass, age and neck circumference / Estudo de ultrassonografia modo-B e Doppler na avaliação das artérias carótidas comuns de equinos e muares e a relação com o peso, idade e a circunferência do pescoço

As age increases, changes in cardiovascular anatomy and physiology occur, even in the absence of disease. Thus, studies of vessel hemodynamics are considered primordial to detect any cardiovascular changes. The objective of this study has been to describe the parameters of B-mode and spectral Doppler ultrasonography in the evaluation of the common carotid arteries of 11 equine and 11 mules, and correlate with age, body mass and neck circumferences. The diameters, intima - media thickness (IMT), resistivity index (RI), pulsatility index (PI), systolic velocity (SV), diastolic velocity (DV), maximum velocity (MV), vascular flow index (VFI), body mass, age, circumference and neck length. Ultrasonographic variables were evaluated in three different region called cranial, middle and caudal. Equine females presented higher values regarding the body mass, age and neck length, as compared to the neck circumferences of the animals, those of the mules were superior. The age of the mules had a positive correlation with the body mass, diameter and neck circumferences, it has a negative correlation between age and vessel diameters. The body mass of the mules had a positive correlation with age and vessel diameters, and with vessel diameters and neck circumferences in equine females. The RI and PI variables had a positive correlation with body mass for mules, and with age for equine females. The DV had a negative correlation with body mass for both equine and mule females. Regarding the variables MV and VFI, age correlated negatively for mules, while it was not significant for equine females. It found a difference between equine females and mules in the correlations performed, with body mass, age, neck circumferences and between B-mode and Doppler ultrasonography variables.(AU)

Com o aumento da idade ocorrem alterações na anatomia e fisiologia cardiovascular, mesmo na ausência de doenças. Assim, os estudos da hemodinâmica dos vasos são considerados primordiais para detectar quaisquer alterações cardiovasculares. Esse trabalho tem como objetivo descrever as variáveis de ultrassonografia modo-B e Doppler espectral na avaliação das artérias carótidas comuns de 11 fêmeas equinas e 11 muares, e correlacionar com idade, massa corpórea e circunferências dos pescoços. Para tais procedimentos foram avaliados os diâmetros, espessura da camada íntima média (EIM), índice de resistividade (IR), índice de pulsatilidade (IP), velocidade sistólica (VS), velocidade diastólica (VD), velocidade máxima (VM), índice de vascularização de fluxo (IVF), massa corpórea, idade, circunferências e comprimentos dos pescoços. As variáveis ultrassonográficas foram avaliadas em três regiões diferentes denominados de crania médio e caudal. As fêmeas equinas apresentaram valores maiores referente ao massa corpórea, idade e comprimento dos pescoços, já em relação às circunferências dos pescoços dos animais, as dos muares foram superiores. A idade dos muares possuiu correlação positiva com a massa corpórea, diâmetro e com as circunferências dos pescoços, com as fêmeas equinas, possui correlação negativa entre idade e os diâmetros dos vasos. A massa corpórea dos muares teve correlação positiva com idade e diâmetros dos vasos, já às fêmeas equinas com diâmetros dos vasos e as circunferências dos pescoços. As variáveis IR e IP tiveram correlação positiva com a massa corpórea para os muares, e com idade para fêmeas equinas. O VD teve correlação negativa com a massa corpórea tanto para as fêmeas equinas quanto nos muares. Já as variáveis VM e IVF, a idade correlacionou negativamente para os muares, enquanto não foi significativo para as fêmeas equinas. Averiguou diferença entre fêmeas equinas e muares nas correlações realizadas, com a massa corpórea, idade, circunferências dos pescoços e entre as variáveis da ultrassonografia modo-B e Doppler.(AU)

Evaluation of tissue Doppler ultrasonographic and strain imaging for assessment of myocardial dysfunction in dogs with type 1 diabetes mellitus.

OBJECTIVE To investigate cardiac structural and functional changes by tissue Doppler imaging (TDI) and strain imaging in dogs with spontaneous type 1 diabetes mellitus. ANIMALS 30 client-owned dogs, of which 10 had normotensive type 1 diabetes mellitus and 20 were healthy. PROCEDURES All dogs underwent physical examination, laboratory analyses, standard echocardiography, and TDI. RESULTS On TDI and strain imaging, transmitral peak early diastolic velocity (E)-to-tissue Doppler-derived peak early diastolic velocity at basal segment (E') of septum ratio, E:lateral E' ratio, and septal tissue Doppler-derived peak late diastolic velocity at basal segment (A') were significantly higher and the septal E':A' ratio and lateral longitudinal strain were significantly lower for diabetic dogs than for control dogs. Furthermore, in diabetic dogs, serum glucose and fructosamine concentrations after a 12-hour period of food withholding were positively correlated with regional systolic functional variables (septal and lateral longitudinal strain) and left ventricular filling pressure indices (E:septal E' and E:lateral E' ratios) but were negatively correlated with diastolic functional variables (E:transmitral peak late diastolic velocity and septal and lateral E':A' ratios). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that myocardial function in diabetic dogs may be altered before the development of clinical heart-associated signs and that the change may be more readily detected by TDI and strain imaging than by conventional echocardiography. In addition, findings indicated that hyperglycemia could have detrimental effects on myocardial function, independent of hypertension, other cardiac diseases, and left ventricular hypertrophy, in dogs with type 1 diabetes.

Power Doppler sonography in the assessment of neovascularization following surgical fracture repair in sheep: case report / Utilização da ultrassonografia Power Doppler no acompanhamento de neovascularização no pós-operatório de ovino submetido a osteossíntese: relato de caso

Sonography is a safe and non-invasive imaging modality, with the added benefit of providing dynamic images. Power Doppler sonography allows blood vessel identification regardless of flow intensity or direction. A one-year-old Ile de France ewe was admitted to the FMVZ-USP Veterinary Hospital with a complete tibial fracture. The animal was submitted to general inhalation anesthesia and fracture repair using a 3.5 mm locking compression plate. Power Doppler sonography was used to assess neovascularization over the course of the bone healing process. Formation of new vessels was noted between postoperative days 14 and 21; new vessels regressed progressively on subsequent assessments (postoperative days 28 and 35). Power Doppler sonography enabled early detection of newly formed blood vessels at the fracture site. The non-invasive nature of this imaging modality prevented patient stress and provided useful information on the progression of bone healing. Early neovascularization was thought to reflect successful postoperative healing of the tibial fracture described.(AU)

A ultrassonografia é técnica de imagem segura e não invasiva que fornece imagens dinâmicas. O Power Doppler é modalidade ultrassonográfica que permite a visualização de vasos sanguíneos sem depender de intensidade e direção de fluxo. Admitiu-se no Hospital Veterinário da FMVZ-USP um ovino fêmea, de raça Ile de France, com um ano de idade e apresentando fratura completa de tíbia em bisel. O animal foi submetido à anestesia inalatória para a realização de osteossíntese com placa bloqueada de 3,5 mm. Durante o período pós-operatório foram realizadas imagens de ultrassonografia Power Doppler para a avaliação da neovascularização ao longo do processo de regeneração óssea. Entre o 14º e o 21º dia do período pós-operatório, identificou-se a presença de vasos sanguíneos neoformados, que apresentaram sinais de regressão nas avaliações subsequentes (realizadas no 28º e no 35º dia pós-operatório). A ultrassonografia Power Doppler mostrou-se eficiente na detecção precoce de vasos sanguíneos neoformados na região da fratura no período pós-operatório, sendo um exame não invasivo, que não gerou estresse para o animal e que pode estar relacionado ao sucesso no reparo ósseo da tíbia do animal submetido à osteossíntese.(AU)

Assessment of Spectral Doppler for an Array-Based Preclinical Ultrasound Scanner Using a Rotating Phantom.

Velocity measurement errors were investigated for an array-based preclinical ultrasound scanner (Vevo 2100, FUJIFILM VisualSonics, Toronto, ON, Canada). Using a small-size rotating phantom made from a tissue-mimicking material, errors in pulse-wave Doppler maximum velocity measurements were observed. The extent of these errors was dependent on the Doppler angle, gate length, gate depth, gate horizontal placement and phantom velocity. Errors were observed to be up to 172% at high beam-target angles. It was found that small gate lengths resulted in larger velocity errors than large gate lengths, a phenomenon that has not previously been reported (e.g., for a beam-target angle of 0°, the error was 27.8% with a 0.2-mm gate length and 5.4% with a 0.98-mm gate length). The error in the velocity measurement with sample volume depth changed depending on the operating frequency of the probe. Some edge effects were observed in the horizontal placement of the sample volume, indicating a change in the array aperture size. The error in the velocity measurements increased with increased phantom velocity, from 22% at 2.4 cm/s to 30% at 26.6 cm/s. To minimise the impact of these errors, an angle-dependent correction factor was derived based on a simple ray model of geometric spectral broadening. Use of this angle-dependent correction factor reduces the maximum velocity measurement errors to <25% in all instances, significantly improving the current estimation of maximum velocity from pulse-wave Doppler ultrasound.

Doppler ultrasonographic assessment of maternal and fetal arteries during normal feline gestation.

The aim of this study was to describe Doppler parameters of uterine, umbilical, fetal abdominal aorta, fetal renal and fetal internal carotid arteries, as well as fetal heart rate (FHR), during normal feline gestation. Fifteen, 1-4 years of age, weighing 2.5-3.9kg, domestic short-hair pregnant queens, which were born in our institutional cat colony were included in this study. Color and pulsed-wave Doppler evaluations of uterine arteries were performed every 10 days (Day 0, 10, 20, 30, 40, 50, 60) from mating. Fetal Doppler and M-mode ultrasonography were performed to assess umbilical, fetal abdominal aorta, fetal renal, fetal internal carotid arteries and FHR. Both peak systolic velocity (PSV) and end diastolic velocity (EDV) of uterine artery increased up to parturition (P<0.01), while resistance index (RI) decreased from Day 10 onwards (P<0.01). From Day 40 onwards, RI of umbilical artery diminished, while PSV and EDV augmented (P<0.01). Fetal abdominal aorta (P<0.01), renal (P<0.01) and internal carotid (P<0.01) arteries diminished their RI from Days 40, 60 and 40 onwards, respectively. Both PSV and EDV of these three arteries increased progressively. Fetal heart rate was first registered on Day 20 when it began to increase up to Day 40 and then diminished to the end of gestation (P<0.01). It is concluded that blood flow of uterine, umbilical, fetal abdominal aorta, fetal renal and fetal internal carotid arteries progressively increased during normal feline pregnancy, while FHR rose to mid gestation and then decreased up to parturition.

Feasibility and reproducibility of echocardiographic assessment of regional left atrial deformation and synchrony by tissue Doppler ultrasonographic imaging in healthy dogs.

OBJECTIVE: To assess the feasibility and reproducibility of longitudinal tissue Doppler ultrasonographic imaging with regard to determination of velocity, strain, and strain rate (SR) of the left atrium (LA) and use those data to characterize LA synchrony (LAS) for a group of healthy dogs. ANIMALS: 15 healthy dogs. PROCEDURES: For each dog, apical 4- and 2-chamber echocardiographic views were obtained. Peak velocity, strain, and SR and time to peak value during systole, early diastole, and late diastole were measured for each of the 4 LA walls. To characterize LAS, mean and SD maximal late diastolic time difference (LAD) among the 4 walls were calculated on the basis of time to peak for velocity, strain, and SR; for each, the 95% confidence interval (mean ± 2SD) was calculated. Within-day and between-day intraobserver variability was calculated. RESULTS: For all dogs, tissue velocity and SR had peak positive values during systole and 2 negative peaks during early and late diastole. Atrial strain had a peak positive value during systole, positive values during early diastole, and a negative peak value during late diastole. Reproducibility was acceptable for most variables. Diastolic strain and SR had the highest variability, but times to peak values were always reproducible. For velocity, strain, and SR, the 95% confidence interval for the maximal LAD was < 50 milliseconds and that for the SD of the LAD was < 23 milliseconds. CONCLUSIONS AND CLINICAL RELEVANCE: Longitudinal tissue Doppler imaging of LA deformation was feasible in healthy dogs, and its application may be useful for understanding atrial pathophysiologic changes associated with various cardiac diseases in dogs.

Doppler ultrasonographic assessment of uterine arteries during normal canine puerperium.

The aim of this study was to describe Doppler ultrasonographic changes of uterine arteries during normal canine puerperium. Eight healthy, pure-bred bitches, were ultrasonographically assessed during the postpartum period on Days -3, 3, 10, 17, 24, 38, 52 and 80 (Day 0 defined as the day of parturition). Total horn diameters (TD) and endometrium thickness (E) were evaluated. Color Doppler was used to localize uterine arteries at both sides of the body and pulsed-wave Doppler was performed to obtain the waveforms. Peak systolic velocity (PSV) and end diastolic velocity (EDV) were measured. Resistance index [(PSV-EDV)/PSV] was automatically calculated. Values of TD, E, PSV, EDV and RI were analyzed by repeated measures ANOVA followed by LSD test (SPSS 18.0; SPSS, Chicago, IL, USA). A correlation analysis was also carried out between RI and TD. A progressive decrease of TD (P<0.01) and E (P<0.01) was found in the course of the study. A gradual diminution of PSV (P<0.01) and EDV (P<0.01) and an increase of RI (P<0.01) were also found throughout the study period. The resistance index negatively correlated with TD (r=-0.46; P<0.01) and E (r=-0.44; P<0.01) while the ultrasonographic and vascular changes in this period are concurrent with regenerative changes in the glandular and epithelial structures of the uterus. It is concluded that uterine artery RI progressively increased during normal canine puerperium, associated to the two-dimensional ultrasonographic regression of the organ.

Assessment of spectral Doppler in preclinical ultrasound using a small-size rotating phantom.

Preclinical ultrasound scanners are used to measure blood flow in small animals, but the potential errors in blood velocity measurements have not been quantified. This investigation rectifies this omission through the design and use of phantoms and evaluation of measurement errors for a preclinical ultrasound system (Vevo 770, Visualsonics, Toronto, ON, Canada). A ray model of geometric spectral broadening was used to predict velocity errors. A small-scale rotating phantom, made from tissue-mimicking material, was developed. True and Doppler-measured maximum velocities of the moving targets were compared over a range of angles from 10° to 80°. Results indicate that the maximum velocity was overestimated by up to 158% by spectral Doppler. There was good agreement (<10%) between theoretical velocity errors and measured errors for beam-target angles of 50°-80°. However, for angles of 10°-40°, the agreement was not as good (>50%). The phantom is capable of validating the performance of blood velocity measurement in preclinical ultrasound.

Assessment of uterine involution in bitches using B-mode and Doppler ultrasonography.

The aim of this study was to measure the uterine diameter by B-mode and Doppler velocimetry patterns of uterine arteries in postpartum female dogs after normal delivery or cesarean section (c-section). Ten female dogs were assessed on weeks 0, 1, 2, 3 and 4 postpartum. Only at week 0, bitches submitted to c-section presented higher body diameters and uterine horns when compared to normal delivery. It was observed a reduction in uterine diameters over the weeks in both groups. In general, bitches submitted to c-section presented lower uterine perfusion. Each group presented distinct Doppler velocimetric characteristics. It was concluded that the B-mode ultrasound and Doppler are important tools for assessing puerperal uterine with distinct characteristics influenced by the type of delivery.

Doppler ultrasonographic assessment of maternal and fetal blood flow in abnormal canine pregnancy.

The aim of this study was to describe the changes of uterine artery, umbilical artery and fetal abdominal aorta, renal and internal carotid arteries blood flow in abnormal canine pregnancy. Twenty-two, Brucella-negative pregnant bitches were retrospectively classified into abnormal (which had either interrupted their pregnancy between days 52 and 60 or had perinatal death >60% of the litter; n=11) and normal (which had delivered healthy puppies at term; n=11). In all the animals, color and pulsed-wave Doppler examinations of uterine artery were conducted every 10 days from Day 20 to 50 from estimated luteinizing hormone peak. Doppler ultrasonography was also conducted in the fetuses to assess umbilical artery, abdominal aorta, renal and internal carotid arteries from Day 40 to 60 of gestation. Throughout the study, resistance index (RI) of uterine, umbilical and fetal renal arteries decreased up to -15% compared to -36% (P<0.01), -11% compared to -23% (P<0.05) and 2% compared to -13% (P<0.05), respectively in the abnormal and normal bitches. Fetal abdominal aorta and internal carotid did not differ between groups (P>0.05). It is concluded that in dogs, uterine artery, umbilical artery and fetal renal artery RI differ between normal and abnormal gestation being useful for the prediction of adverse obstetric outcome.

Ultrasonographic assessment of maternal cardiac function and peripheral circulation during normal gestation in dogs.

The aim of this study was to describe changes in cardiac morphology, systolic function and some peripheral hemodynamic parameters during normal pregnancy in dogs. Twenty healthy bitches, 10 pregnant (PG) and 10 non-pregnant controls (CG), were evaluated every 10 days using echocardiography from day 0 of the estrus cycle to parturition or to day 65 for the PG and CG groups, respectively. Systolic blood pressure (SBP) and uterine artery resistance index (RI) were also assessed. Throughout the study, the shortening fraction and cardiac output increased up to 30% vs. 5% (P<0.01) and 45% vs. 2% (P<0.01) in the PG and CG groups, respectively. In contrast, SBP and RI diminished up to 20% vs. 1% (P<0.01) and 29% vs. 0% (P<0.01) in the PG and CG groups, respectively. In conclusion, a decrease in afterload, an increase in cardiac output and cardiac hypertrophy appear to be the result of the hemodynamic modifications occurring during pregnancy in dogs.

Conceptus ecobiometry and triplex Doppler ultrasonography of uterine and umbilical arteries for assessment of fetal viability in dogs.

The objectives were to: 1) evaluate blood flow in the uterine (UA) and umbilical (Uma) arteries in the pregnant bitch, by measuring the resistive index (RI) and pulsatility index (PI); 2) to note the presence or absence of the early diastolic notch and diastolic flow in the UA and Uma flow waveforms, respectively; and 3) perform conceptus ecobiometry for fetal growth assessment during pregnancy. Six healthy bitches were examined on approximately Days -44, -42, -36, -31, -28, -25, -21, -18, -14, -8, -4, and -2 of pregnancy (whelping = Day 0). Triplex Doppler and B-mode ultrasonography were used to assess blood flow and conceptus ecobiometry. All pregnancies ended with a normal whelping and birth of live puppies. Prior to whelping, all conceptus dimensions increased significantly, whereas RI and PI of both the Uma and UA decreased significantly. For the UA, RI and PI were (mean +/- SEM) 0.95 +/- 0.02 and 2.75 +/- 0.41, respectively, on Day -44, and were 0.60 +/- 0.01 and 0.99 +/- 0.03 on Day -4. For the Uma, RI and PI were 0.99 +/- 0.01 and 2.42 +/- 0.03 on Day -31, and were 0.62 +/- 0.01 and 1.15 +/- 0.02 on Day -4. The complete disappearance of the early diastolic notch in the UA, and the appearance of diastolic flow in the Uma occurred on Days -16 +/- 5 and -21 +/- 1. The authors concluded that UA and Uma perfusion were important end points to assess fetal vitality in bitches. Furthermore, the current reference values provided a baseline for monitoring normal and abnormal pregnancies in bitches.

Vascular ultrasound studies for the non-invasive assessment of vascular flow and patency in experimental surgery in the pig.

Vascular ultrasound is a reliable non-invasive tool used for the routine assessment of vascular flow and patency in human recipients. We describe the use at three different time points (immediately, 1 week and 4 weeks postsurgery) of ultrasound studies and its validation by angiographic studies in 37 swine undergoing carotid graft replacement. We calculated predictive values (>92%), sensitivity (>85%) and specificity (>92%) with high results at all time points. Ultrasound appeared as an accessible non-invasive technique, providing rapid, safe, repeatable and reliable results. It is an excellent alternative to angiography, avoiding risks inherent to invasive methods and therefore contributing to animal welfare.