Spectral waveform analysis of major arteries in conscious dogs by Doppler ultrasonography

Normal values of arterial blood flow velocity and waveforms in major arteries of 10 healthy conscious Beagle dogs were determined using Doppler ultrasonography. Peak systolic, early diastolic, and end-diastolic velocities of the basilar artery, common carotid artery, abdominal aorta, external iliac artery, femoral artery, and peak ejection velocity of the valvular aorta were evaluated. Pulsatility index (PI) of the basilar artery and blood pressure were recorded. All arteries had a high-resistance flow pattern with triphasic flow velocity except the basilar artery, which had a low-resistance pattern. Mean peak systolic velocities of the basilar artery, common carotid artery, abdominal aorta, external iliac artery, and femoral artery were 72 +/- 19, 115 +/- 17, 121 +/- 24, 105 +/- 25, and 110 +/- 17 cm/s, respectively. The PI of the basilar artery and peak ejection velocity of the valvular aorta were 1.37 +/- 0.13 and 96 +/- 16 cm/s, respectively. Mean systolic and diastolic blood pressures were 137 +/- 13 and 78 +/- 15 mmHg, respectively. Present findings may be used as references in future studies on vascular diseases and hemodynamics in dogs.     

Effects of medetomidine on doppler variables of major abdominal arteries in normal dogs

The purpose of this study was to evaluate the effects of medetomidine administration on the Doppler variables of abdominal arteries. The study population consisted of 20 healthy dogs. The haemodynamic effects of the medetomidine were defined using Doppler variables of the abdominal aorta, renal arteries, cranial mesenteric artery and celiac artery. The dogs were monitored continuously and different measurements were performed before medetomidine injection, at 10, 40 and 80 minutes after medetomidine medication and after atipamezole administration. Changes in the characteristic Doppler spectra of different vessels were more marked in the abdominal aorta, in which a greater reverse flow was found. There was a significant decrease in peak systolic velocity (PSV), end diastolic velocity (EDV), and mean velocity (MV) at ten minutes in every vessel studied and this effect persisted until atipamezole administration. Pulsatility index (PI) increased significantly in the abdominal aorta at ten minutes and persisted during the study until atipamezole administration. Resistive index (RI) did not vary significantly in any vessel. A significant decrease was found in flow volume of the abdominal aorta, the cranial mesenteric artery and the celiac artery at ten minutes, persisting until atipamezole administration. We conclude that medetomidine can be a good sedative in aiding sonographic evaluation of RI in all the abdominal vessels studied. On the other hand, the changes in other Doppler variables suggest that medetomidine administration causes significant hemodynamic differences between sedated and non-sedated dogs.     

Evaluation of haemodynamic changes of uterine arteries using Doppler ultrasonography during different stages of pregnancy in Bos indicus cows

The objectives of the study were to evaluate haemodynamic changes and their relationships among ipsilateral (IPS) and contralateral (CONT) uterine arteries (UA) during different stages of pregnancy in Bos indicus cows. Multiparous pregnant cows (n = 40) having a gestation length 30.47 ± 0.54 (mean ± SD) days were randomly enrolled and subjected to Doppler ultrasonography sequentially at 1st, 2nd, 4th, 6th and 8th months of gestation. Blood flow indices including diameter of UA (mm), blood flow volume (BFVo, ml/min), blood flow velocity (BFVe, cm/s), time-averaged maximum velocity (TAMV, cm/s), pulsatility index (PI) and resistance index (RI) were recorded. Data were analysed with mixed models using the PROC MIXED procedures, and Pearson correlation coefficients were calculated using the PROC CORR statement in SAS. The final statistical models included the fixed effects of side of UA, gestation month and the interaction between side of UA and gestation month. Results revealed that the mean diameter of the UA (12.13 ± 0.22 vs. 10.09 ± 0.22), BFVo (1236.33 ± 0.55 vs. 770.41 ± 0.55), BFVe (17.18 ± 0.42 vs. 15.58 ± 0.42) and TAMV (17.11 ± 0.44 vs. 15.77 ± 0.44) was higher (p < .05) in IPS as compared to CONT side of the UA in cows. However, PI and RI did not differ between IPS and CON arteries of uterus in cows. A very high and positive correlation (r = .89; p < .05) existed between the diameter of UA and BFVo starting from 1st to 8th months of gestation in IPS as well as CONT sides of UA. Moreover, TAMV was highly and positively correlated (r = .91; p < .05) with BFVe throughout the gestation. In conclusion, these haemodynamic changes in the UA could be used as a valuable validity tool to differentiate the compromised pregnancy in Bos indicus cows.     

Contrast-enhanced ultrasound analysis of renal perfusion in normal micropigs

Contrast-enhanced ultrasound is one of method for evaluating renal perfusion. The purpose of this project was to assess perfusion patterns and dynamics in normal micropig kidney using ultrasonographic contrast media. Eight young healthy micropigs were included in this study. Micropigs were anesthetized with propofol and received an intravenous bolus of microbubble contrast media through an ear vein. Time/mean pixel value (MPV) curves were generated for selected regions in the right renal cortex and medulla. The parenchyma was enhanced in two phases. The cortex was first enhanced followed by a more gradual enhancement of the medulla. A significant difference in perfusion was detected between the cortex and medulla. Following the bolus injection, the average upslope was 0.68 ± 0.27 MPV/sec, downslope was -0.27 ± 0.13 MPV/sec, baseline was 73.9 ± 16.5 MPV, peak was 84.6 ± 17.2 MPV, and time-to-peak (from injection) was 17.5 ± 6.6 sec for the cortex. For the medulla, the average upslope was 0.50 ± 0.24 MPV/sec, downslope was -0.12 ± 0.06 MPV/sec, baseline was 52.7 ± 7.0 MPV, peak was 65.2 ± 9.3 MPV, and time-to-peak (from injection) was 27.5 ± 5.0 sec. These data can be used as normal reference values for studying young micropigs.     

Colour Doppler ultrasound imaging of blood flows variations in neoplastic and non‐neoplastic testicular lesions in dogs

Testicular tumours are the most common neoplasms in male dogs accounting for approximately 90% of all tumours affecting the genitourinary tract. Gray‐scale ultrasonography in combination with colour and power Doppler imaging has been well accepted as an accurate technique for assessing scrotal lesions and vascularization of the testis. Colour Doppler sensitivity for low blood flows appears promising in the study of testicular disorders. The aim of this study was to assess if colour and power Doppler ultrasound is a good tool for the investigation of testicular lesions in dogs, to report the sonographic features of lesions and to measure colour and power Doppler parameters such as resistive index (RI), pulsatility index (PI), hypovascularization and hypervascularization (VI) determining if they can be used to distinguish testicular neoplasms from the wide spectrum of non‐neoplastic pathological findings. In this study, 50 male dogs of various breeds, aged between 7 and 14 years, presented with testicular disorders were selected. RI and PI were calculated. Mean RI values for neoplastic, inflammatory and degenerative lesions were 0.54, 0.45 and 0.58, respectively. Mean PI values were 0.62, 0.55 and 0.63, respectively. Hypovascularization and hypervascularization of the lesion were evaluated throughout the vascularity index (VI). Vascular signals in neoplasms were significantly intensified around and inside the mass if compared with those measured during inflammatory and degenerative lesions. VI markedly increased in solid tumours. Pathological testes were removed; macroscopical, histological and immunoistochemical evaluations were carried out. Colour Doppler showed increased intralesional and peripheral flows in all neoplastic lesions analysed. No flows were detected around cysts.     

Two-dimensional grayscale ultrasound and spectral Doppler waveform evaluation of dogs with chronic enteropathies

Sonography is an important diagnostic tool to examine the gastrointestinal tract of dogs with chronic diarrhea. Two-dimensional grayscale ultrasound parameters to assess for various enteropathies primarily focus on wall thickness and layering. Mild, generalized thickening of the intestinal wall with maintenance of the wall layering is common in inflammatory bowel disease. Quantitative and semi-quantitative spectral Doppler arterial waveform analysis can be utilized for various enteropathies, including inflammatory bowel disease and food allergies. Dogs with inflammatory bowel disease have inadequate hemodynamic responses during digestion of food. Dogs with food allergies have prolonged vasodilation and lower resistive and pulsatility indices after eating allergen-inducing foods.     

Effects of cuff size and position on the agreement between arterial blood pressure measured by Doppler ultrasound and through a dorsal pedal artery catheter in anesthetized cats

ObjectiveTo compare the effects of cuff size/position on the agreement between arterial blood pressure measured by Doppler ultrasound (ABP_Doppler) and dorsal pedal artery catheter measurements of systolic (SAP_invasive) and mean arterial pressure (MAP_invasive) in anesthetized cats.Study designProspective study.AnimalsA total of eight cats (3.0–3.8 kg) for neutering.MethodsDuring isoflurane anesthesia, before surgery, changes in end-tidal isoflurane concentrations and/or administration of dopamine were performed to achieve SAP_invasive within 60–150 mmHg. Cuff sizes 1, 2 and 3 (bladder width: 20, 25 and 35 mm, respectively) were placed on distal third of the antebrachium, above the tarsus and below the tarsus for ABP_Doppler measurements. Agreement between ABP_Doppler and SAP_invasive or between ABP_Doppler and MAP_invasive was compared with reference standards for noninvasive blood pressure devices used in humans and small animals.ResultsMean bias and precision (±standard deviation) between ABP_Doppler and SAP_invasive met veterinary standards (≤10 ± 15 mmHg), but not human standards (≤5 ± 8 mmHg), with cuffs 1 and 2 placed on the thoracic limb (7.4 ± 13.9 and –5.8 ± 9.5 mmHg, respectively), and with cuff 2 placed proximal to the tarsus (7.2 ± 12.4 mmHg). Cuff width-to-limb circumference ratios resulting in acceptable agreement between ABP_Doppler and SAP_invasive were 0.31 ± 0.04 (cuff 1) and 0.42 ± 0.05 (cuff 2) on the thoracic limb, and 0.43 ± 0.05 (cuff 2) above the tarsus. ABP_Doppler showed no acceptable agreement with MAP_invasive by any reference standard.Conclusions and clinical relevanceThe agreement between ABP_Doppler and SAP_invasive can be optimized by placing the occlusive cuff on the distal third of the antebrachium and above the tarsus. In these locations, cuff width should approach 40% of limb circumference to provide clinically acceptable estimations of SAP_invasive. Doppler ultrasound cannot be used to estimate MAP_invasive in cats.     

Comparison of Pulsed Wave and Color Doppler Myocardial Velocity Imaging in Healthy Dogs

Background: Tissue velocity imaging (TVI) is increasingly used in small animal cardiology. Tissue velocity of the myocardial wall can be measured by pulsed wave (PW) or color Doppler (CD) imaging methods. Currently, the same reference ranges are used for PW TVI and CD TVI methods. However, if and how both methods correlate, and whether they can be used interchangeably, have not been assessed in small animals. Objectives: To compare the results of PW TVI and CD TVI measurements. Animals: Seventy‐one healthy dogs. Methods: Longitudinal myocardial velocity profiles were recorded from the 4‐chamber left apical view. Peak maximal systolic (S), early (E), and late diastolic (A) velocities were measured off‐line in a blinded fashion in the septal and lateral left ventricular wall by PW TVI and CD TVI. Differences between peak PW TVI and CD TVI waves were analyzed by a paired t‐test. Regression analysis and Bland‐Altman difference plots also were used to assess agreement between methods. Results: There was a significant correlation between PW TVI and CD TVI (P < .001). However, S, E, and A waves measured by PW TVI were significantly higher than the CD TVI values (P < .001). Peak systolic and diastolic PW velocities were approximately 2.20 cm/s higher than corresponding mean CD TVI velocities. Conclusions and Clinical Importance: PW TVI measurements are significantly higher compared with CD TVI measurements. Theses differences are clinically relevant. These methods should not be used interchangeably, and different reference ranges for PW TVI and CD TVI should be used.     

Comparison of high definition oscillometric and Doppler ultrasound devices with invasive blood pressure in anaesthetized dogs

Objective To use the American College of Veterinary Internal Medicine (ACVIM) validation criteria to evaluate the performance of high definition oscillometric (HDO) and Doppler blood pressure measurement techniques against invasive blood pressure measurements in anaesthetized dogs. Study design Prospective clinical study. Animals Twenty client‐owned dogs. Materials and Methods Invasive blood pressure was measured using a catheter inserted into a pedal artery and an electronic transducer. The sites of cuff placement for the HDO measurements were the mid antebrachium or the proximal tail and, for the Doppler technique, the distal tibia. Agreement between invasive and non‐invasive blood pressure measurements was estimated by the Bland–Altman method. Results Only 10% and 34% of Doppler measurements were within 10 and 20 mmHg of invasive blood pressure values, respectively. The Doppler device failed to meet the ACVIM validation criteria for blood pressure measurement devices. The best agreement between HDO and invasive blood pressure measurement technique was observed for mean arterial blood pressure (MAP); 67% and 95% of readings were within 10 and 20 mmHg of invasive blood pressure values respectively. In addition, 52% and 87% of diastolic arterial blood pressure (DAP) measurements were within 10 and 20 mmHg of invasive readings. High definition oscillometric readings did not meet ACVIM recommended limits for SAP. Conclusion and clinical relevance The Doppler technique overestimated and the HDO device showed limited agreement with invasive blood pressure measurement in anaesthetized dogs. High definition oscillometry met most of the ACVIM requirements for MAP and DAP while the Doppler technique did not.     

Assessing the Association Between Hoof Thermography and Hoof Doppler Ultrasonography for the Diagnosis of Lameness in Horses

The objectives of this study were to assess the correlation between hoof surface temperature and ultrasonographic measurements of digital blood vessels in horses and to evaluate the measurements' potential as predictors for clinical lameness. Twelve 3-year-old American Quarter Horses, 6 geldings and 6 mares, with average initial body weight of 459 ± 31 kg were used. On days 0, 30, 60, and 90 of the study, horses were weighed and subjected to clinical lameness examinations. Doppler ultrasonography was used to measure diameter of the medial palmar artery in the distal left forelimb and velocity of blood flow through that artery, starting at 60 minutes after morning feeding and repeated at 30-minute intervals. Temperature measurements on the hoof were collected at 15-minute intervals beginning 75 minutes after feeding, using a digital thermographic camera. A series of bivariate linear mixed models were fitted to estimate the correlation between Doppler and temperature measurements. The within-horse and between-horse correlations between hoof surface temperature and velocity of blood flow in the distal limb through the medial palmar artery was estimated at 0.40 (P > .50) and 0.99 (P < .001), respectively. These results indicate that at the horse level, the correlation between hoof temperature and velocity of blood flow in the distal limb was very high but that the within-horse correlation was not significantly different from 0. Velocity of blood flow at 60 minutes after feeding improved model fit to the lameness data, so it was included as a model predictor for lameness.     

Assessment of diastolic function by Doppler echocardiography in normal Doberman Pinschers and Doberman Pinschers with dilated cardiomyopathy

BACKGROUND: Assessment of diastolic function in patients with dilated cardiomyopathy (DCM) has the potential to add valuable information regarding hemodynamics, disease severity, and prognosis. The purpose of this study was to determine transmitral flow (TMF), isovolumic relaxation time (IVRT), pulmonary venous flow (PVF), flow propagation velocity (Vp), and mitral annular velocities by tissue Doppler in Doberman Pinschers with and without DCM. HYPOTHESIS: It was anticipated that normal and DCM Dobermans would differ with respect to these parameters, and that associations with time to congestive heart failure (CHF) or death would be found. ANIMALS: Thirty client-owned Doberman Pinschers (10 each of normal, occult DCM, and overt DCM) were studied. METHODS: Each dog underwent echocardiography with or without thoracic radiography (to confirm CHF) for classification as normal or DCM-affected, followed by collection of echocardiographic diastolic parameters. RESULTS: The group with occult DCM exhibited features of pseudonormal TMF, reduced systolic to diastolic PVF ratio, and reduced Vp. Shorter early TMF deceleration time (DTE) was associated with shorter time to CHF or sudden death. The group with overt DCM exhibited restrictive TMF, blunted systolic PVF, and reduced early and late diastolic mitral annular velocities. CONCLUSIONS AND CLINICAL IMPORTANCE: Doberman Pinschers showed evidence of moderate and severe diastolic dysfunction in occult and overt DCM, respectively. Short DTE may be a useful predictor of onset of CHF or sudden death.     

Systolic time intervals assessed by 2-D echocardiography and spectral Doppler in the horse

In the present study, the ‘acoustic windows’ for the measurement of the left ventricular systolic time intervals is studied by means of 2‐D echocardiography and cardiac Doppler ultrasonography, and the normal values in the horse (n = 112) are determined. The left ventricular isovolumetric contraction time, the pre‐ejection period (PEP), as well as the left ventricular ejection time (LVET) have been measured, and the values of the left ventricular total electromechanical systole (LVTES) and the PEP‐to‐LVET ratio have been calculated. It has been established that the most suitable window for the measurement of the aforementioned indices in 2‐D echocardiography is the right parasternal window in a view in short axis at the level of the cardiac base to measure the aortogram. In Doppler ultrasonography, the preferred window is the left parasternal using the five chambers apical view. The following values have been acquired: PEP = 0.071 ± 0.01 s; LVET = 0.532 ± 0.097 s; LVTES = 0.6 ± 0.1 s and PEP‐to‐LVET = 0.138 ± 0.025 measured by 2‐D echocardiography and PEP = 0.068 ± 0.009 s; LVET = 0.527 ± 0.076 s; LVTES = 0.598 ± 0.098 s and PEP‐to‐LVET = 0.131 ± 0.01 measured by Doppler ultrasonography.     

The effect of an L-type calcium channel blocker on the hemodynamics of orbital arteries in dogs

Purpose (1) To determine the effect of the l ‐type calcium channel blocker amlodipine on color Doppler ultrasound‐determined vascular resistance and blood flow velocities in the distal retrobulbar arteries of dogs; (2) to determine any effect of blood pressure and PCO₂ rate on such color Doppler‐determined circulatory measurements. Methods Color Doppler imaging measurements of the short posterior ciliary artery, long posterior ciliary artery, and ophthalmic artery of normal eyes of 10 dogs were obtained under isofluorane anesthesia before and 1 week after oral amlodipine administration. Mean systemic arterial blood pressure and PCO₂ were monitored. Results The mean resistive index decreased significantly in the short posterior ciliary artery (P = 0.0347), in the long posterior ciliary artery (P = 0.0092), and ophthalmic artery (P = 0.0004) following systemic amlodipine administration. The end diastolic velocity increased significantly in the long posterior ciliary artery (P = 0.0368) and ophthalmic artery (P < 0.0001). The peak systolic velocity increased significantly in the ophthalmic artery (P = 0.0256). Mean systemic arterial blood pressure was significantly negatively associated with resistive index (P < 0.0001) and significantly associated with the log of the end diastolic velocity (P < 0.0001). Conclusions Systemically administered amlodipine increases color Doppler imaging‐determined blood flow velocity and decreases vascular resistive index in the ophthalmic artery, short posterior ciliary artery and long posterior ciliary artery of normal dogs. Changes in systemic arterial blood pressure can significantly affect the measurement of color Doppler imaging parameters.     

Doppler evaluation of maternal and fetal vessels during normal gestation in the bitch

The aim of this work is to evaluate the haemodynamic characteristics of maternal and fetal vessels during normal pregnancy in bitches, using Colour and Pulsed wave Doppler ultrasonography, in order to obtain more information about maternal and fetal circulation. The blood waveforms of the uteroplacental arteries, aorta, caudal cava vein and umbilical cord of the fetuses were recorded weekly in 16 pregnant bitches. Also, the measurements of Peak Systolic, End Diastolic Velocities, Resistance and Pulsatility Indices were carried out. Uteroplacental blood flow was biphasic while the ones of the umbilical artery and aorta were first systolic and then diastolic. The cava showed a typical waveform of venous vessels. During gestation the EDV and PSV of fetal vessels increased (alpha<0.05) while the PI and RI of all vessels examined decreased (alpha<0.05) except for the IP of the Aorta. The Doppler ultrasonography was used to study the characteristics of maternal and fetal vessel flow and their progressive changes during pregnancy. This study can be considered a further contribution in diagnosing and monitoring high-risk pregnancies in Veterinary Medicine.     

Gross Anatomical,Radiographic and Doppler Sonographic Approach to the Infra-auricular Parotid Region in Donkey (Equus asinus)

The present study was performed on 12 heads of donkey’s cadavers of both sexes for different anatomic techniques and on 20 live adult donkeys for ultrasonographic approaches of local anesthetic techniques. The aim was to achieve safe desensitization of the ear canal and tympanic membrane in addition to measuring different parameters of the structures occupying the infra-auricular parotid region. The internal auricular nerve was divided into two fine branches and constituting, at its origin, a characteristic V-shape with the caudal auricular nerve. The styloid process of auricular cartilage was an adequate landmark for ultrasonographic needle-guided anesthesia for internal auricular and auriculopalpebral nerves, whereas the great auricular nerve was easily palpated subcutaneously that showed safety and success in all cases. The auricular branch of mandibular nerve joined the auriculopalpebral branch of facial nerve. The maxillary vein was descending, partially embedded within the texture of the parotid glandular tissue. The parotid gland divided into five segments was clearly demarcated by maxillary vein tributaries with three main collecting radicles pouring into the parotid duct. The mandibular duct received about 12–15 fine radicles and supplied with a separate branch from the external carotid artery. Using the Doppler sonographic technique in donkeys for diagnosis of ear affections, evaluation of retrograde sialography to salivary glands with their blood vasculature and their indices might be helpful for the detection of different critical abnormalities, such as stenosis, thrombosis, and other vasopathological affections through measuring their resistivity and pulsatility indices.     

Comparison of direct and Doppler arterial blood pressure measurements in rabbits during isoflurane anaesthesia

ObjectiveTo measure the level of agreement between Doppler measured (DOP) arterial blood pressure (ABP) in the forelimb and directly measured (DIR) auricular systolic ABP (SAP) and mean ABP (MAP) in isoflurane-anaesthetized rabbits.Study designProspective clinical study.AnimalsData were analysed from 17 of 24 healthy rabbits, weighing 1.3–2.8 kg.MethodsRabbits were anaesthetized for neutering using a standardized protocol. A 26G catheter placed in an auricular artery was connected via heparinised saline filled non-compliant tubing (regularly flushed) to a calibrated pressure transducer (zeroed level with the thoracic inlet) to obtain DIR ABP. A cuff was placed proximal to the carpus (approximately level with the thoracic inlet) and a Doppler transducer sited over the dorsal carpal branch of the radial artery to obtain DOP ABP. Simultaneous DIR and DOP ABP recordings were made every 5–10 minutes during anaesthesia. Agreement was assessed as described by Bland JM &; Altman (2007).ResultsMean ± SD cuff width: limb circumference ratio was 0.50 ± 0.04. Mean between-method differences ± SD, DIR SAP- DOP and DIR MAP- DOP, were +1 ± 8 and ?13 ± 8 mmHg respectively. The 95% limits of agreement between DIR SAP and DOP and between DIR MAP and DOP were ?14 to +17 and ?28 to +2 mmHg respectively. Differences between DIR SAP and DOP were ≤10 mmHg 85% of the time. Defining hypotension as either DIR SAP < 80 mmHg or DIR MAP < 60 mmHg, and taking DOP ABP of <80 mmHg to indicate hypotension, sensitivity and specificity were 92% and 67% respectively.ConclusionsGood agreement was found between DIR SAP and DOP. Doppler measurements below 80 mmHg are a reliable indicator of arterial hypotension.Clinical relevanceDOP is acceptable for monitoring ABP in isoflurane-anaesthetized rabbits and is useful for detection of hypotension.     

Evaluation of oscillometric and Doppler ultrasonic devices for blood pressure measurements in anesthetized and conscious dogs

Two non-invasive blood pressure (NIBP) devices (oscillometry and Doppler) were compared to invasive blood pressure using a Bland–Altman analysis, in anesthetized and conscious dogs. When considering the systolic arterial pressure only during general anesthesia, both NIBP devices slightly underestimated the systolic arterial blood pressure however the precision and the limits of agreement for the Doppler were of a greater magnitude. This indicates a worse clinical performance by the Doppler. The performance of both NIBP devices deteriorated as measured in conscious animals. In general, for the oscillometric device, determination of invasive diastolic and mean arterial pressures was better than the invasive systolic arterial pressure. Overall, the oscillometric device satisfied more of the criteria set by the American College of Veterinary Internal Medicine consensus statement. Based upon these results, the oscillometric device is more reliable than the Doppler in the determination of blood pressure in healthy medium to large breed dogs.     

Doppler imaging of the ophthalmic vasculature of the normal dog: blood velocity measurements and reproducibility

The purpose of this study was to assess the feasibility and reproducibility of color Doppler imaging (CDI) of the vasculature of the normal canine orbit and eye. Eight normal Beagles were evaluated by Doppler imaging. The goals of the study were to determine the location, spectral waveform morphology, specific blood velocity parameters, and reproducibility for the ophthalmic and orbital vessels most frequently identified in the normal dog. Vessels identified a majority of the time (> 50%) included: external ophthalmic artery, dorsal external ophthalmic vein, ventral external ophthalmic vein, internal ophthalmic artery, anterior ciliary artery and vein, short and long posterior ciliary arteries, primary retinal arteries, and vortex veins. Other vessels imaged less frequently included: external ethmoidal artery (50%), and primary retinal veins (25%). For each blood vessel the time averaged velocity, peak systolic velocity, minimum diastolic velocity, pulsatility index, and resistive index were determined. The ophthalmic and orbital vessels have unique spectral waveforms and velocities which serve as a basis for identification. Reproducibility of the most commonly imaged vessels of the canine eye and orbit with Doppler imaging was high (< 10% variation). Doppler imaging has the potential for determining noninvasively and consecutively the blood velocity parameters found in orbital and ocular diseases, including orbital inflammations and neoplasms; intraocular inflammations and neoplasms; vascular diseases including systemic vascular disease (hypertension), vasculopathies, and anemia; the glaucomas; and documentable follow-up after medical and/or surgical treatment of these diseases.     

Evaluation of ovarian blood flow by colour Doppler ultrasound: practical use for reproductive management in the cow

Transrectal real-time ultrasonography (US) has been developed as a research and practical tool in bovine reproduction. Non-invasive US observations have made it possible to provide real-time and serial analyses of ovarian morphological changes and fetal development and have generated new information on reproductive physiology during the bovine oestrous cycle and pregnancy. This has greatly contributed to an understanding of the real-time dynamics of follicular development. US has also allowed for more accurate diagnosis compared with rectal palpation in reproductive management in cattle. Practical applications of US include early diagnosis of pregnancy, identification of twin fetuses, detection of ovarian and uterine pathologies and determination of fetal sex.In recent years, local blood flow has been analysed in individual ovarian follicles and the corpus luteum (CL) in the cow using colour Doppler US. From these observations, it has been found that (1) the blood supply to follicles is closely related to follicular growth, atresia and ovulation, (2) the blood supply to the CL increases in parallel with its growth, and (3) there is an acute increase in blood flow in the mature CL prior to luteal regression. Colour Doppler US may provide an estimate of the physiological status of follicles and corpora lutea. For example, images of blood flow can be used to assess the thickness of the follicular wall and provide a differential diagnosis of follicular and luteal cysts. Assessment of the area of blood flow in the CL using colour Doppler imaging may offer a useful adjunct in estimating CL function, which could be applied to the diagnosis of non-pregnancy and fetal loss. The number of small follicles which have blood flow at the start of gonadotrophin treatment may be a useful index to predict the superovulatory response.With improvements in portability and cost-effectiveness, the evaluation of ovarian blood flow by colour Doppler US is likely to become widely used as a diagnostic tool for monitoring ovarian function in dairy cattle.