8. June 2018|
Elizabeth Huynh, DVM, is an imaging resident and graduate student at the University of Florida College of Veterinary Medicine. Her interests include ultrasound, cross-sectional imaging, and nuclear medicine. She received her DVM from Ross University, completed her clinical year at Ohio State University, and completed an imaging internship at the Animal Specialty and Emergency Center in Los Angeles, California.
Read articles by Elizabeth Huynh
Erin G. Porter
dr Porter is a 2007 graduate of the University of Florida College of Veterinary Medicine. After graduating, she worked as an outpatient equine physician in the Orlando area for two years before returning to the University of Florida for an internship in imaging and lameness. Dr Porter received her residency in diagnostic imaging from the University of Florida and became a graduate of the American College of Veterinary Radiology in 2013. Since 2013 she has been a Clinical Assistant Professor of Diagnostic Imaging at the University of Florida. Her interests include equine orthopedic imaging and small animal ultrasound. She currently resides in Alachua, FL with her husband (Michael) and two young children.
Read articles by Erin G. Porter
Clifford R. Berry
Dr Berry is Assistant Professor of Diagnostic Imaging at the University of Florida and Assistant Clinical Professor of Diagnostic Imaging at North Carolina State University College of Veterinary Medicine. He received his DVM from the University of Florida and completed his radiology residency at the University of California-Davis. He has a special interest in breast imaging.
Updated October 2022
Read articles by Clifford R. Berry
Welcome to our series of articles on abdominal ultrasound in small animals. Early articles provided an overview of the basic principles of ultrasonography and a discussion of how to perform a routine abdominal examination. The remainder of the series covers ultrasound examination of specific abdominal organs/systems.
Indications for imaging the abdominal vasculature include ruling out neoplastic vascular invasion, determining the presence or absence of suspicious congenital vascular abnormalities, and identifying intravascular thrombi (eg, when hypercoagulability is suspected). The ability to identify the abdominal vasculature is also important, as these vessels are used to find normal anatomical structures such as the pancreas, lymph nodes, and adrenal glands.
A complete examination of the abdominal vasculature and lymph nodes, if identifiable, is part of a complete abdominal ultrasound examination and requires experience and understanding of Doppler ultrasound techniques and anatomy. For more details on the relationship between abdominal vessels and lymph nodes, see the July/August 2017 Imaging Essentials article "Ultrasonography of the peritoneal and retroperitoneal spaces and abdominal lymph nodes.“
Doppler ultrasound is used to assess blood flow characteristics: presence or absence, direction, velocity and type (laminar versus turbulent flow). The 4 Doppler techniques used in ultrasound are continuous wave, pulsed wave, power and color Doppler, which are divided into spectral representations and color modes. The advantages and disadvantages of the techniques used in abdominal ultrasound are summarized inTABLE 1.1The Doppler principle is based on the Doppler shift frequency equation (ILLUSTRATION 1). The frequency shift is in the kHz range and is audible when viewing spectral Doppler images.
The image is displayed as blood flow velocity (y-axis) versus time (x-axis). Ideally, for spectral Doppler imaging, the sample line is parallel to the region of interest or aligned with the blood flow so that the angle of incidence of the ultrasound beam is 0°. At a 90° angle of incidence, no flow is displayed (ILLUSTRATION 1).
FIGURE 1. Ultrasound Doppler plot and Doppler shift frequency equation. The ultrasound machine measures the Doppler shift (fd) as the difference between the transmitted (ft) and reflected ultrasound frequencies as a result of red blood cell movement. The equation shows that the measurement of fd is related to the velocity (V) of blood flow. The speed of sound (c) in tissue is assumed to be constant at 1540 m/s for this calculation. Note that cos 90° is 0; Therefore, if the foot angle is 90°, the measured blood flow will be 0.
Two types of spectral Doppler techniques are used today: continuous wave and pulsed wave.
Continuous Wave DopplerIt is used in echocardiography. It uses phased array transducers that contain multiple crystals that transmit and receive ultrasonic waves independently and continuously. The advantage of continuous wave Doppler is that it can measure high blood flow velocities (>6 m/s) with high accuracy (no aliasing artifacts;BOX 1). It also indicates the direction of blood flow relative to the transducer: flow towards the transducer is above baseline (positive direction) and flow away from the transducer is below baseline (negative direction). Its drawback is that flow velocities are recorded along the interrogation line and a specific anatomical location along that line is not accurately recorded. Is calledclassification ambiguity.
BOX 1 Aliasing in pulsed spectral Doppler images
pseudonymon the pulse wave Doppler spectral image, it is an artifact that appears as a "skin" of peak velocities on the opposite side of the pulse wave spectral display in the y direction. The maximum velocity (up to 1.5 to 2.0 m/sec) that can be accurately recorded in Pulse Wave Doppler is a function of the sampling rate, also called the sampling rate.Pulswiederholrate(PRF) and query sample volume depth. For a given PRF, the maximum frequency shift that can be recorded without aliasing is equal to half the PRF. This maximum variation is known asNyquist limit.
To reduce aliasing, the sonographer can increase the PRF (often called scaling on ultrasound machines), decrease the baseline, or decrease the sample volume depth to allow the PRF to increase without depth limitations. When the PRF is properly adjusted, aliasing indicates rapid or turbulent blood flow. The incidence angle can be corrected by a sampling port angle correction; However, an angle greater than 60° is not recommended.
Pulsed Wave DopplerIt is used in both echocardiography and abdominal/vascular ultrasound. Pulsed wave Doppler uses the pulse-echo principle (the same crystal transmits and receives the ultrasonic wave) to measure the velocity, direction and pattern of blood flow (laminar vs turbulent).
The advantage of pulsed Doppler is that the precise anatomical location of the return velocity can be accurately recorded, indicating where the ultrasound transducer should "listen" for the return echoes along the Doppler interrogation line. The specified range, known asSampling Gate, is displayed as two parallel lines along the question mark. There is no classification ambiguity.
A disadvantage of pulsed Doppler is that it is affected by aliasing artifacts at higher velocities (> 2.0 m/s;BOX 1). This clearly affects the usefulness of pulsed Doppler in echocardiography, where pathological velocities can easily exceed this limit; However, pulsed Doppler is suitable for vascular assessment in the abdomen.
When pulse wave Doppler is used for abdominal vessels, the angle between the vessel being examined and the transducer on the skin surface will never reach 0°. Therefore, these machines have an adjustment wheel for angle correction. Angles > 60° result in inaccurate sampling at maximum flow.
One color Doppler display
In this form of pulse-echo Doppler, the returning frequencies are displayed on a color screen known as a BART.azulindicates flowdistantof the converter andRedindicates flowforthe color spectrum of the converter indicates the distance or speed scale, which is usually shown in the figure on the right.
Color Dopplershows the presence or absence, direction, velocity and character (laminar vs. turbulent) of blood flow. With this technique, the color Doppler switch is turned on and a box (sample window) is superimposed on the grayscale image. In this frame, frequency changes based on the presence of movement in the vessels result in a color display of the velocity of each pixel (FIGURE 2). An existing color display is calleddetour map, where velocities that exceed the pulse repetition rate are shown in green instead of being aliased and grouped in the opposite colored column.
FIGURE 2. (A) Longitudinal view of the right kidney in a normal cat with color Doppler. Note the red vessels, which indicate blood flow into the transducer, and the blue vessels, which indicate flow out of the transducer. (B) Color Doppler image of the caudal vena cava of a dog in recumbency, seen from the right side along the long axis. Aliasing (red, yellow, and orange) is seen because the pulse repetition rate or Doppler scale is too low at 6.0 cm/s. (C) The same dog as B. The Doppler scale was correctly adjusted to 18.4 cm/s to eliminate aliasing.
Power-Dopplerit only indicates the presence or absence of blood flow. Some ultrasound machines have directional power Doppler images that record the presence and direction of flow. These settings are not as sensitive as power Doppler without the heading information (FIGURE 3).
FIGURE 3. (A) Long axis of the right kidney in a normal cat with power Doppler as seen in FIGURE 2A. This procedure detects the presence of blood flow but does not provide information about the direction, speed or turbulence of the flow. Note that the aliases are not visible. (B) Directional power Doppler of a jejunal lymph node affected by lymphoma in a cat. This image provides directional information and the presence or absence of flow. Note the abnormally enlarged and infiltrated lymph node.
All normal blood vessels have certain sonographic properties. The vessel lumen should be anechoic on grayscale ultrasound. Slice thickness artifacts can introduce disorder into the lumen, but color Doppler interrogation of the vessel in the short and long axis planes helps to distinguish between artifact and anomaly. When performed with the correct device setup, color Doppler interrogation of vessels should result in a solid color within the lumen, indicating flow in the expected direction toward (red) or away from (blue) the transducer (FIGURE 2). It is important to note that, depending on the direction of blood flow in the vessel relative to the transducer, flow in arteries and veins may be displayed in red, blue, or both colors in the same vessel. For example, if the transducer is perpendicular to the aorta and the transducer marker is pointing cranially, the flow in the aorta will be red on the left side of the viewport and blue on the right side of the viewport.
Preparation and scanning technique
Examination of the abdominal vasculature is part of a routine complete abdominal ultrasound examination. Before starting the examination, cut the patient's hair and apply ultrasound gel to the skin. Normal vascularity of the abdominal cranial organs (liver, spleen and left kidney) should be assessed. The arteries surrounding the left adrenal gland are used to locate this gland. If the ultrasound scanner scans the abdominal cavity clockwise, the examination of the caudal abdominal vessels can be reviewed after examining the urinary bladder and reproductive tract.
Begin by tilting the transducer from the left caudal aspect of the left paralumbar space ventral to the hypaxial muscles to image the retroperitoneal cavity in the long axis. The aorta and caudal vena cava can be seen dorsally to the urinary bladder and descending colon. When images are acquired from the left, the aorta is dorsal and in the near field and the caudal vena cava is ventral and in the far field.
Then place the transducer in a similar position on the patient's right side, again aligned longitudinally with the patient and angled dorsally toward the retroperitoneal cavity. This window shows the caudal vena cava in the near field and the aorta in the far field. In addition to using anatomical landmarks to identify the aorta and the caudal vena cava, the sonographic and physiological characteristics of these vessels can be considered: the aorta is pulsatile, while the caudal vena cava is compressible (it flattens slightly when the probe is pressed). lines the abdominal wall).
Complete assessment of the aorta and caudal vena cava in long- and short-axis views of the patient requires tracing their course caudally to the trifurcation (origin of the left and right external iliac artery and continuation of the caudal abdominal aorta) and cranially. for the cranial abdominal efferent arteries from the aorta, including the renal arteries and veins, the cranial mesenteric artery, and the celiac artery.FIGURE 4).
FIGURE 4. (A) Diagram of the portal vein, caudal vena cava and its main abdominal and accessory branches. (B) Diagram of the aorta and its main abdominal branches. an artery; Vader.
Normal sonographic features of the abdominal vasculature
Routine abdominal ultrasound should visualize the aorta, caudal vena cava, portal vein system, and its branches/tributaries (FIGURE 4).
The aorta is best visualized in the caudal abdomen, just to the left of the midline, where it parallels the caudal (right) vena cava from the level of L3 to L6. The caudal vena cava and aorta diverge cranial to L3.
The aorta is dorsal to the caudal vena cava along the abdomen to the level of L6-L7, where the inferior vena cava and common iliac vein pass dorsal to the aorta and its caudal branches. The cranial mesenteric and celiac arteries can be identified as they exit the cranial aorta into the renal artery; its location is important for identifying the left adrenal gland (FIGURE 4). Color Doppler is needed to identify smaller arteries. In the trifurcation of the caudal abdominal aorta, the medial iliac lymph nodes border the lateral borders of the aorta and the external iliac artery on the right and left.
Aortic diameter can be used as an internal reference to assess kidney size in dogs.2This is an important parameter when assessing kidney disease in dogs. One study showed that the ratio between the length of the left kidney, measured in the long axis plane, and the diameter of the adjacent aortic lumen (LK:Ao) should range from 5.5 to 9.1 in normal dogs.2
The aorta should be a straight anechoic tube with no mineralization within its wall. The walls of the aorta are discrete hyperechoic lines that do not change in diameter until the trifurcation in the caudal abdomen. The normal pulsed Doppler spectral display contains a three-phase peak, with peak velocities being achieved during ventricular systole. There is a brief reversal in flow (signal drops below baseline), followed by a positive recovery in the compliance and elasticity of the ascending aorta and aortic arch.Rasseleffekt;Figura 5A). Laminar blood flow within the aorta should cause a relatively dead area in the middle of the ascending systolic excursion. Normal systolic velocities in the aorta range from 1.0 to 1.5 m/s.
FIGURE 5. Doppler analysis of pulse wave of a 1 year old mongrel dog under sedation (Dexdomitor 0.25 mcg/kg). (A) Long-axis view of the abdominal aorta from a right-side window documenting the typical triphasic appearance on pulsed Doppler spectral recording. Maximum speed is generally < 1 m/sec. The dog had a sinus arrhythmia, so after the prolonged diastolic pause there was a “stronger” systolic contraction (increased stretching of the myocardial fibers due to increased ventricular filling; S); the first contraction is louder (faster) than the other 2 beats during inspiration. (B) Long-axis view of the caudal vena cava as shown on the right. Due to the decrease in heart rate due to sedation, there are 4 peaks on the caudal vena cava pulsed Doppler spectral trace instead of the standard 3. The initial positive offset (note that the spectral trace has been inverted as the position of the sampling gate; would be measured by the transducer goes away) represents ventricular systole. The diastolic filling phase was divided into 2 parts (d1 and d2) and there is flow reversal in atrial contraction (A). (C) Long-axis view of the portal vein, as shown on the right. The portal vein pulsed Doppler spectral recording has a typical appearance with a flat profile and is not affected by cardiac cycle or respiration.
The caudal vena cava is most clearly seen in the abdomen to the right of the midline, where it runs parallel and adjacent to the aorta in the caudal abdomen, and in the cranial abdomen, where it crosses the right side of the liver before crossing the diaphragm. At the level of L3, the caudal vena cava begins its ventral course (away from the aorta and dorsal position in the abdomen) to the level of a middiaphragmatic position in the cranial abdomen, as seen on chest radiographs.
The cranial portion of the caudal abdominal vein at the level of the caudate process of the caudate lobe of the liver serves as a reference point for locating the right adrenal gland, as the right adrenal gland lies directly dorsolateral or lateral to the caudal vein at the level of the o. renal hilum. Cats store fat between the caudal lobe of the liver (renal pit) and the right kidney (more caudal than dogs). In cats, the right adrenal gland is located cranial to the right kidney on the lateral border of the caudal vena cava at the level of the liver.
The pulsed Doppler spectral waveform is complex and is affected by the cardiac cycle, respiratory phase, and patient movement.FIGURE 5B). When the vessel is imaged directing blood flow to the transducer, there is an initial positive waveform at the time of ventricular systole. Before the waveform reaches baseline, there is another positive spike during late diastolic filling as right ventricular and right atrial pressures increase; During atrial contraction, negative deflection occurs as blood flows from the right atrium into the right ventricle. As flow velocity in the caudal vena cava varies, a laminar flow pattern cannot be observed. Peak velocities in the caudal vena cava (at the time of right ventricular systole) usually range from 20 to 35 cm/s.
The portal vein has a characteristic flat pulsed vein Doppler profile (FIGURE 5C) and is located within the porta hepatis, dorsal to the body of the pancreas. Cranially, the portal vein is formed by the confluence of the cranial and caudal mesenteric portal veins, the splenic portal vein, and the gastroduodenal portal vein. The portal vein proper is a very short vessel that leads to the portal vein and gives rise to the right dividing branch (right lobe of the liver) and the central dividing branch (rectangular and middle lobe of the liver) and continues as the left dividing branch ( right lobe of the liver). ) left liver). rags). The flow pattern is non-laminar and typical flow velocities are 15 to 25 cm/sec.
Thromboembolic disease can affect any intra-abdominal vessel and is caused by a hypercoagulable state (Table 2).1,3–11
On ultrasound, chronic thrombi appear as hyperechoic tissue in the vessel lumen, resulting in partial or complete obstruction of visible blood flow.FIGURE 6). Acutely, thrombi can be difficult to visualize because they are anechoic. If thrombi are suspected, interrogation with color, power, and pulse wave Doppler is recommended, and all lesions should be confirmed by long-axis and short-axis imaging.
FIGURE 6. (A) Long axis and (B) short axis of the caudal vena cava at the level of the right adrenal gland in a dog with a pheochromocytoma invading the adjacent vena cava. In A, note the echogenic structure formed filling much of the lumen of the caudal vena cava, resulting in low-field flux from the caudal vena cava when examined with color Doppler. In B, the formed echogenic thrombus fills most of the caudal vena cava (half-moon-shaped anechoic structure) and part of the adjacent phreno-abdominal vein. A hypoechoic mass of the right adrenal gland is also present.
Animals presented in a hypercoagulable state may exhibit slow blood flow that can be detected before thrombus formation. On grayscale images, this can appear as echogenic "smoke" in the vessels, likely due to spontaneous agglutination of red blood cells, which increases backscatter and blood echogenicity.
Comprehensive screening for thromboembolism includes assessment of the following items12:
- Acute thrombi (using color Doppler and pulsed wave)
- Extent and location of visible thrombi (using color Doppler to assess collateral circulation)
- Peripheral blood flow (using color Doppler)
- Evidence of neoplasia in the region.
- Consequences of thrombosis (eg, ischemia of distal structures/organs assessed by color Doppler; ascites due to portal vein thrombosis)
Vascular anomalies that do not originate in the portal vein system are rare. Other imaging methods, such as B. CT angiography, are usually required for definitive diagnosis.
Caudal vena cava thrombosis
Abnormalities of the caudal vena cava are most often associated with neoplasm of the right adrenal gland, but may occur secondary to invasive neoplasm of the left adrenal gland, liver, lymph nodes, or kidney, or by spreading venous, femoral, or iliac thrombosis Difficult to distinguish between thromboses, which are blood clots, and those that represent true tumor thrombi. Both blood clots and tumor thrombi appear as echogenic structures within the vessel lumen. The color Doppler image shows a filling defect within the vessel (FIGURE 6). Complete occlusion results in no flow beyond the lesion. Partial occlusion can cause turbulence adjacent to the lesion or alias. However, if the tumor is vascular, a flow pattern within the thrombus may be seen, particularly when power Doppler is used. This finding would be consistent with a tumor thrombus.
Portal vein thrombosis occurs in numerous diseases associated with the development of coagulopathies.2,13It is recognized sonographically as intraluminal structures with moderate to high echogenicity and absence of color Doppler signals within the lumen.14(FIGURE 7). Thrombosis can be focal or extend to all branches of the portal venous system, resulting in secondary portal venous hypertension, acquired extrahepatic portosystemic shunts (PSS), and ascites.
FIGURE 7. Short-axis view of the portal vein, represented by the anechoic structure in the near field, and the caudal vena cava, represented by the anechoic structure in the far field, at the level of the hepatic portal in an adult dog with hypercoagulopathy ( PARA). Note the ovoid echogenic structure in the portal vein lumen (A) and the interrupted color Doppler signal with a filling defect in the lumen compatible with a portal vein thrombus (B).
Thromboembolism in the aorta and iliac artery is more common in cats with primary cardiomyopathy; in dogs, it may be secondary to neoplasms, heart disease or hypercoagulable conditions. Ultrasound features resemble those of a venous thrombus.
hepatic venous congestion
Congestion is usually secondary to increased resistance to blood flow from the caudal vena cava to the right atrium. Causes of hepatic venous congestion include obstruction by a mass in the right atrium, pericardial effusion, invasion of the caudal vena cava by a tumor, and right-sided congestive heart failure.15Dilation of the hepatic veins and caudal vena cava is best visualized adjacent to the diaphragm at the level of the right cranial dorsal abdomen (10th or 11th intercostal approaches). Simultaneous findings are diffusely hypoechoic liver parenchyma, hepatomegaly and peritoneal effusion.
Congenital portosystemic shunts
Congenital PSS are single, large, abnormal connections between the portal and systemic veins that allow portal blood from the gastrointestinal tract to bypass the liver. Congenital PSS is more common in dogs than cats. A congenital shunt can be intrahepatic or extrahepatic. A full description and review of this material is beyond the scope of this article, so only the essentials will be discussed here.
Congenital intrahepatic PSS occurs predominantly in large breed dogs and is often attributed to a persistent ductus venosus, which arises from the left intrahepatic division of the portal vein and connects to the left hepatic vein.16,17If they arise from the right branch of the portal vein, these shunts drain directly into the caudal vein.
Congenital extrahepatic PSS in dogs are connections between the portal system (either the portal vein or one of its afferents, such as the left gastric vein, splenic vein, or gastroduodenal vein) and the systemic venous circulation (either the caudal vein or the azygos). Vein). Come to).
Cats can have intrahepatic or extrahepatic shunts; The morphology of extrahepatic shunts varies greatly depending on their origin, course and end.18,19
Extrahepatic portacaval shunts usually arise from the spleen, right gastric vein, or left gastric vein and enter the caudal vena cava between the phrenoabdominal vein and the diaphragm. They are usually identified as a tortuous vessel with hepatofugal flow seen by color Doppler or pulse wave.hepatofugaler FlussIt leaves the liver within the portal vein or one of its afferents, unlike in normal dogs and cats, where the portal vein flows into the liver (hepatopetal flow). The vena cava, portal vein, and portal vein area should be scanned from the diaphragm to the level of the kidneys for an abnormal branching vessel entering the vena cava or migrating dorsally through the diaphragm into the azygos vein adjacent to the aorta. The entry point of portacaval shunts into the caudal vena cava can be identified by detecting turbulent flow using color and pulse wave Doppler.FIGURE 8).
FIGURE 8. Short-axis view of the liver (A) without and (B) with color Doppler at the level of the portal vein and caudal vena cava in a 2-month-old mixed breed dog with intrahepatic portacaval shunt. Note the turbulent blood flow, indicated by the aliasing artifact, in the lumen of the abnormal shunt vessel and the portal vein. This turbulence is consistent with an extrahepatic portacaval shunt.
The acoustic windows include the right caudal and subxiphoid intercostal spaces of the last 3 ribs, relatively close to the spine where the liver cranial to the right kidney is visible. Using these intercostal windows, the sonographer can obtain short-axis images of the adjacent aorta, caudal vena cava, and portal vein.FIGURE 9). The bypass vessel runs between the vena cava and the portal vein (FIGURE 8). The size of the portal vein can also be measured at the dorsal intercostal window 12 or 11. The size of the cranial portal vein in the bypass is usually small in diameter. When the portal vein is measured cranial to the gastroduodenal-portal junction, a portal vein-aortic diameter ratio of ≤ 0.65 is predictive of the presence of an extrahepatic shunt, and a value of ≥ 0.80 excludes it.FIGURE 9).20When the ratio is ≥ 0.80, other types of diseases such as microvascular dysplasia, intrahepatic shunt (FIGURE 10) and portal hypertension due to chronic liver disease with a secondary extrahepatic ESP may still be present.
FIGURE 9. Short axis view of the hepatic portal vein and aorta in a dog. The ratio of portal vein to aorta diameter is 0.84, indicating that this dog is unlikely to have an abnormal extrahepatic portosystemic shunt.
FIGURE 10. Short-axis section of the left hepatic segment in a 5-month-old golden retriever with a single intrahepatic portosystemic shunt (A) with and (B) without color Doppler. Note the cystic, round, anechoic structure representing the portal vein (PV) on the left of the image. A large distended vessel connects to the caudal vena cava. Aliasing and turbulence are evident in the portal vein, bypass vessels, and caudal vena cava in A.
The sensitivity and specificity of ultrasonography for detecting extrahepatic ESP were given as 80.5% and 66.7%, respectively; a greater sensitivity of 100% was observed for intrahepatic PSS alone.21Also microhepathy, bilateral renomegaly, nephrocalcinosis, nephroliths and cystoliths due to urate crystals.22,23or stones can be identified.24
Purchased portosystemic shunts
Multiple acquired extrahepatic ESPs develop as a result of chronic portal hypertension and result in decreased hepatic perfusion. Causes of portal hypertension include chronic liver disease with fibrosis, cirrhosis, some forms of infiltrative neoplasia, congenital portal hypoplasia, hepatic arteriovenous fistula, portal vein thrombosis, and extraluminal compression of the portal vein. The most common causes of portal hypertension in dogs are disorders that cause right heart failure.15,25-27and severe diffuse hepatobiliary disease,28result in cirrhosis.
On ultrasound, acquired extrahepatic PSS is recognized as multiple small, collateral, tortuous vessels connecting the portal vein or its tributaries to the inferior vena cava and/or renal/gonadal, mesenteric, and colonic veins, resulting in clinical signs of PSS.FIGURE 11). Ascites is commonly found in association with portal hypertension, with decreased blood flow in the main portal vein at mean velocities ≤ 10 cm/s as measured by spectral Doppler ultrasound.29
FIGURE 11. Long-axis view (two-dimensional with color Doppler overlay) of the left abdomen near the left kidney at the level of the aorta and caudal vena cava in an 8-year-old poodle with multiple extrahepatic portosystemic shunts (color circle). Surgery). vascular) secondary to liver cirrhosis due to the toxicity of the sago palm.
Hepatic arteriovenous fistula
Hepatic arteriovenous malformations (fistulas) can be congenital or, more rarely, acquired. They connect the hepatic arteries and the portal vein. Elevation of high-pressure arterial blood into the low-pressure intrahepatic portal system causes the development of severe portal hypertension. These animals usually present with severe ascites at an early age.30,31
Ultrasonography shows a strong enlargement of the intrahepatic portal branches and the main portal vein (FIGURE 12). Doppler interrogation of these dilated branches reveals turbulent pulsatile flow indicating communication with the arterial system (FIGURE 12). Examination caudal to the liver, particularly in the renal and left gonadal vein area, often reveals numerous small, tortuous vessels consistent with acquired PSS.
FIGURE 12. Short-axis section of the left hepatic segment in a 6-year-old poodle with multiple hepatic arteriovenous fistulas (A) without color Doppler, (B) with color Doppler and (C) with power Doppler. Note the tortuous spectrum of vessels in color and power Doppler images, which is not visible in the two-dimensional grayscale image. (D) The pulse wave Doppler display of one of the vessels in the image is seen as a continuous flow pattern with an arterial peak and no return to baseline, consistent with an arteriovenous fistula.
A working knowledge of abdominal vascular anatomy is required to locate small structures and assess primary abnormalities of the aorta, caudal vena cava, and portal system. A systematic assessment using color, power and pulse wave Doppler of the various organs and/or vessels requires time and patience. As with normal echogenicity and echotexture of abdominal organs, the sonographer should detect normal color, power, and pulse wave Doppler flow patterns.
- Gorgas D. Physical principles. In: Barr F, Gaschen F, eds.BSAVA Manual of Canine and Feline Ultrasound. Quedgeley: British Association of Small Animal Veterinarians; 2012: 1-14.
- Marechal A, d'Anjou MA, Moreau M, et al. Ultrasonographic measurement of the kidney-aorta relationship as a method to estimate kidney size in dogs.Radiol Veterinary Ultrasound2007;48:434-438.
- Mattoon J., Nyland T.Manual of Veterinary Ultrasound for Small Animals. 3ra ed. San Luis: Elsevier Saunders; 2015.
- Llabres-Diaz F.abdominal vessels. Gloucester: British Association of Small Animal Veterinarians; 2009.
- Dennis R., Kirberger R.M., Barr F. et al.Differential diagnosis in small animal radiology. 2nd Edition: Elsevier Limited; 2010
- Chun R, Jakovljevic S, Morrison WB, et al. Adenocarcinoma and pheochromocytoma of the apocrine glands in a cat.GELB1997;33(1):33-36.
- Frank JR, Nutter FB, Kyles AE, et al. Systemic arterial dirofilariasis in five dogs.J Trainee Veterinarian1997;11(3):189-194.
- Welles EG, Boudreaux MK, Crager CS, et al. Platelet function and antithrombin, plasminogen, and fibrinolytic activities in cats with heart disease.Am J Vet Res1994;55(5):619-627.
- Ritt MG, Rogers KS, Thomas JS. Nephrotic syndrome leading to thromboembolic disease and disseminated intravascular coagulation in a dog.GELB1997;33(5):385-391.
- Sykes JE, Kittleson MD, Chomel BB, et al. Clinicopathological findings and results in dogs with infective endocarditis: 71 cases (1992-2005).JAVMAGenericName2006;228(11):1735-1747.
- Ware WA, Fenner WR. Arterial thromboembolic disease in a dog with blastomycosis located in the hilar lymph node.JAVMAGenericName1988;193(7):847-849.
- Zwingenberger A. Ultrasound of arterial and venous thrombosis. 2007. veterinariaradiology.net/341/ultrasound-of-arterial-and-venous-thrombosis/. Consulted in January 2018.
- Respess M, O'Toole TE, Taeymans O, et al. Pfortaderthrombose bei 33 Hunden: 1998-2011.J Trainee Veterinarian2012;26(2):230-237.
- Cordeiro CR, Burton CA, Carlisle CH. Hepatic arterial flow Doppler in dogs: technique and preliminary results.Radiol Veterinary Ultrasound1999;40(1):77-81.
- Edwards DF, Bahr RJ, Suter PF, et al. Portal hypertension secondary to a right atrial tumor in a dog.JAVMAGenericName1978;173(6):750-755.
- White RN, Burton CA. Anatomy of the persistent ductus venosus in the cat.J Feline Med Surgery2001;3(4):229-233.
- White RN, Burton CA. Anatomy of the persistent ductus venosus in the dog.Veterinary Medicine2000;146(15):425-429.
- Ruland K, Fischer A, Reese S, et al. Portosystemic shunts in cats: evaluation of six cases and review of the literature.Berl Munch Veterinary Nurse2009;122(5-6):211-218.
- Cordero CR, Forster-van Hijfte MA, White RN, et al. Ultrasonographic diagnosis of congenital portosystemic shunt in 14 cats.small animal practice J1996;37(5):205-209.
- d'Anjou MA, Penninck D, Cornejo L, et al. Ultrasonographic diagnosis of portosystemic shunts in dogs and cats.Radiol Veterinary Ultrasound2004;45(5):424-437.
- Holt DE, Schelling CG, Saunders HM, et al. Correlation of sonographic findings with surgical, portographic and autopsy findings in dogs and cats with portosystemic shunts: 63 cases (1987-1993).JAVMAGenericName1995;207(9):1190-1193.
- Caro JD, Shiraki R, Ruby AL, et al. Feline urolithiasis: retrospective study of 159 cases.J Feline Med Surgery2011;13(10):725-732.
- G Caporali EH, Phillips H, Underwood L, et al. Risk factors for urolithiasis in dogs with congenital extrahepatic portosystemic shunts: 95 cases (1999-2013).JAVMAGenericName2015;246(5):530-536.
- Boothe HW, Howe LM, Edwards JF, et al. Multiple extrahepatic portosystemic shunts in dogs: 30 cases (1981-1993).JAVMAGenericName1996;208(11):1849-1854.
- Calvert CA, Thrall DE. Treatment of heartworm disease in dogs with concomitant right heart failure.JAVMAGenericName1982;180(10):1201-1203.
- Berg RJ, Wingfield WE, Hoopes PJ. Idiopathic hemorrhagic pericardial effusion in eight dogs.JAVMAGenericName1984;185(9):988-992.
- Fingland RB, Bonagura JD, Myer CW. Pulmonary stenosis in the dog: 29 cases (1975-1984).JAVMAGenericName1986;189(2):218-226.
- Twedt DC. Cirrhosis: a consequence of chronic liver disease.Vet Clin North Am Small Animal Clinic1985;15(1):151-176.
- Bunch SE, Johnson SE, Cullen JM. Idiopathic non-cirrhotic portal hypertension in dogs: 33 cases (1982-1998).JAVMAGenericName2001;218(3):392-399.
- Szatmari V, Nemeth T, Kotai I, et al. Ultrasonographic Doppler Diagnosis and Anatomy of Congenital Intrahepatic Arterioportal Fistula in a Puppy.Radiol Veterinary Ultrasound2000;41(3):284-286.
- Schermerhorn T, Center SA, Dykes NL, et al. Suspected microscopic hepatic arteriovenous fistula in a young dog.JAVMAGenericName1997;211(1):70-74.
What does a vascular abdominal ultrasound show? ›
An abdominal ultrasound is done to see the blood vessels and organs in the belly area. Your health care provider may recommend this test if you have a condition affecting any of these body areas: Blood vessels in the abdomen. Gallbladder.Why would cardiologist order an ultrasound of abdomen? ›
This test helps your physician determine if there are blockages, narrowing or aneurysm (an enlargement or a “bulge”) in your aorta, which is a large artery in your abdomen. Ultrasound is used to obtain images of the aorta and the blood flow within. The test is noninvasive and should cause no significant discomfort.What diseases can an abdominal ultrasound detect? ›
- Bladder stones.
- Enlarged spleen.
- Cholecystitis (gallbladder inflammation).
- Pancreatitis (inflamed pancreas).
- Cancer, such as stomach cancer or pancreatic cancer.
- Fatty liver disease.
- Abdominal aortic aneurysm (a bulge in the aorta wall in your midsection).
This is the most common test to diagnose abdominal aortic aneurysms. An abdominal ultrasound is a painless test that uses sound waves to show how blood flows through the structures in the belly area, including the aorta.
You should consider a vascular screening if you have risk factors for any vascular disorder. A family history of stroke, aneurysm, or Peripheral Artery Disease suggests the need for screening, often beginning in the 30s – particularly if other risk factors co-exist.Would an abdominal ultrasound show a blockage? ›
CONCLUSION: Ultrasound can play an important role in the identification of small bowel obstructions in ED patients.Can abdominal ultrasound detect colon problems? ›
Abdominal ultrasound: For this exam, a technician moves the transducer along the skin over your abdomen. This type of ultrasound can be used to look for tumors in your liver, gallbladder, pancreas, or elsewhere in your abdomen, but it can't look for tumors of the colon or rectum.Does abdominal ultrasound show inflammation? ›
SW Ultrasound is an excellent test for IBD. It is very accurate for looking at disease activity or intestinal inflammation. It provides exceptional information both about the status of the bowel and the presence of any complications.What not to do before an abdominal ultrasound? ›
- You must not eat or drink for eight hours before your exam. You can drink a little water to take your medications. ...
- Please wear comfortable clothing (ideally without metal) and leave your jewelry and valuables at home.
- Please call (805) 681-7671 if you have any questions regarding your exam.
With ultrasound scans, the scanned images show up immediately on the device's screen. This means that often the person operating the scanner can give immediate feedback - provided they're suitably qualified to interpret the images. So, most likely you'll get a verbal summary of the results immediately.
Can stomach tumor be detected by ultrasound? ›
Ultrasound produces images of organs from high-energy sound waves and echoes to help your care team detect and stage stomach cancer. It may also be used to check for tumors that have spread to other organs.What organs does a limited abdominal ultrasound show? ›
Abdominal ultrasounds can be ordered a complete or limited. The abdomen limited includes images of the pancreas, liver, gallbladder, and right kidney. The abdomen complete includes imaging the aorta, IVC, pancreas, liver, gallbladder, right and left kidneys, and spleen.Can ultrasound detect colon polyps? ›
Although ultrasound is clearly not one of the widely accepted screening techniques, this non-invasive and radiation-free modality is also capable of detecting colonic polyps, both benign and malignant. Such colon lesions may be encountered when not expected, usually during general abdominal sonography.What does red mean on an abdominal ultrasound? ›
What does red or blue mean on an ultrasound? Red and blue colors represent the movement of the blood. Blue represents blood flow away from the probe, while red represents the blood flowing towards the probe.What are the symptoms of an aneurysm in the stomach? ›
In most cases, an AAA causes no noticeable symptoms. However, if it becomes large, some people may develop a pain or a pulsating feeling in their abdomen (tummy) or persistent back pain. An AAA doesn't usually pose a serious threat to health, but there's a risk that a larger aneurysm could burst (rupture).What is the difference between ultrasound and vascular ultrasound? ›
Because ultrasound captures images in real-time, it can show the structure and movement of the body's internal organs. The images can also show blood flowing through blood vessels. Vascular ultrasound provides pictures of the body's veins and arteries.How do you know if you have a vascular problem? ›
Pale or bluish skin. Lack of leg hair or toenail growth. Sores on toes, feet, or legs that heal slowly or not at all. Decreased skin temperature, or thin, brittle, shiny skin on the legs and feet.How do you prepare for a vascular ultrasound? ›
- Adults: Do not eat or drink eight hours before exam.
- Children: Do not eat or drink four hours before study, or skip one meal.
- Take medications with a small sip of water.
- If you are diabetic, please take your insulin.
If you do have a blocked artery, you may not be able to tell. You can't feel a clogged artery, so many people don't know they have blocked arteries until they experience an emergency such as a heart attack. Fortunately, certain lifestyle changes and treatments can help lower your risk of a blocked artery.What are the signs of intestinal obstruction in ultrasound? ›
Obstructed bowel loops appear sonographically to be dilated, thickened wall and fluid filled with hyperechoic spots (gas). Acute care physicians performing point-of-care ultrasound following up patients with mechanical IO should know the warning signs of possible bowel ischemia.
Can ultrasound detect diverticulitis? ›
Studies in the hands of expert bowel sonographers show ultrasound has a sensitivity and specificity of >80% for the diagnosis of diverticulitis.Does IBS show up on abdominal ultrasound? ›
IBS cannot be seen on an ultrasound, CT scan, MRI, or colonoscopy. Patients who see a gastroenterologist for abdominal pain will often have testing and imaging (most commonly an ultrasound or a CT scan) completed to rule out other causes of abdominal pain.Can ultrasound detect colon inflammation? ›
Ultrasound appears to be accurate in distinguishing normal from inflamed colon, but ultrasound findings alone should not be used to determine the cause of bowel inflammation.Can ultrasound detect gastritis? ›
While inflammatory diseases such as gastritis or ulcers are usually not detected by ultrasonography, a circumscribed thickening of the gastric or duodenal wall with an echogenic center is occasionally seen in gastroduodenal ulcers [8,9].Can liver inflammation be seen on ultrasound? ›
Both ultrasound and MR elastography can detect increased stiffness of the liver caused by liver fibrosis earlier than other imaging tests and may eliminate the need for an invasive liver biopsy.Should I poop before abdominal ultrasound? ›
You must not eat or drink for eight hours before your exam. Water and taking medication is okay. If ultrasound pelvis is also being done, for female patients, please drink 32 ounces of water one hour before the scan. You can go to the bathroom to relieve yourself, as long as you keep drinking water.Is it OK to drink water before an abdominal ultrasound? ›
If you eat anything within 6 hours of your exam, your gallbladder may not look normal in the ultrasound images. During your fast, you may drink clear liquids such as black coffee, tea, and water. Do not drink anything that contains fat or sugar.How many ounces of water should I drink before an abdominal ultrasound? ›
Abdominal and pelvic ultrasound
You must have a full bladder when you arrive at the clinic. Make sure you drink four eight-ounce glasses (960 ml total) of water or juice 75 minutes before the exam and don't urinate.
“Plenty of patients ask, but techs should not give information and should not even react to what they're seeing on the image,” Edwards said. “They aren't doctors, and while they do know how to get around your anatomy, they aren't qualified to diagnose you.”How accurate are abdominal ultrasounds? ›
Ultrasound accuracy, as confirmed by operation, was highest for splenic masses (100%) and for aortic aneurysm (88%). Liver masses were correctly identified in 56% of patients and gallbladder lesions in 38%. While only a 48% accuracy was obtained in diagnosing pancreatic disease, 64% of all pseudocysts were localized.
Do you get ultrasound results immediately? ›
Generally speaking, most ultrasounds will take anywhere from 30 minutes to an hour to complete, and in most cases, you are told the results as soon as you finish the scan, but the actual image may need to be analyzed by the radiologist. The written report will be available soon after the test.Can you tell if a lump is cancerous from an ultrasound? ›
Ultrasound images are not as detailed as those from CT or MRI scans. Ultrasound cannot tell whether a tumor is cancer. Its use is also limited in some parts of the body because the sound waves can't go through air (such as in the lungs) or through bone.What are the symptoms of tumor in stomach? ›
- persistent indigestion.
- trapped wind and frequent burping.
- feeling full very quickly when eating.
- feeling bloated after eating.
- feeling sick.
- pain in your stomach or breastbone.
- difficulty swallowing (dysphagia)
Stomach cancer can present itself in several different ways, such as difficulty swallowing, feeling bloated after eating, feeling full after only eating a small amount of food, heartburn, indigestion, nausea, stomach pain, unintentional weight loss, and vomiting.What are common abnormal findings in the abdomen? ›
Inspection of the Abdomen
The presence of any abnormal masses may indicate umbilical hernia, ventral wall hernia, femoral hernia, or inguinal hernia, depending on the location. The patient may be asked to cough, which results in raised intraabdominal pressure, causing the hernia to become more prominent.
Following your appointment today, it has not been possible to confirm whether your pregnancy is likely to continue or not. We know that it can be difficult to take in all the facts when you are worried and upset, especially in a hospital environment.Can ultrasound detect tumors in colon? ›
Although not suitable as a first choice screening procedure for colorectal cancer, routine abdominal ultrasound can detect even non-suspected colonic tumors, especially in the ascending colon. Since the specificity of ultrasound is probably low, diagnosis must be confirmed by X-ray and/or endoscopy.What are the symptoms of cancerous polyps in the colon? ›
- Rectal bleeding. This can be a sign of colon polyps or cancer or other conditions, such as hemorrhoids or minor tears of the anus.
- Change in stool color. Blood can show up as red streaks in your stool or make stool appear black. ...
- Change in bowel habits. ...
- Pain. ...
- Iron deficiency anemia.
But some larger polyps can cause:
- a small amount of slime (mucus) or blood in your poo (rectal bleeding)
- diarrhoea or constipation.
- pain in your tummy (abdominal pain)
On an ultrasound cancerous tissue shows up black and dense tissue is still white, therefore cancers are easier to distinguish.
Why would a doctor order an abdominal ultrasound? ›
Doctors order an abdominal ultrasound when they're concerned about symptoms such as belly pain, repeated vomiting, abnormal liver or kidney function tests, or a swollen belly. The tests can show them the size of the abdominal organs and help them check for injuries to or diseases of the organs.What are the 3 most common causes of abdominal aneurysms? ›
- Hardening of the arteries (atherosclerosis). Atherosclerosis occurs when fat and other substances build up on the lining of a blood vessel.
- High blood pressure. High blood pressure can damage and weaken the aorta's walls.
- Blood vessel diseases. ...
- Infection in the aorta. ...
The pain associated with an abdominal aortic aneurysm may be located in the abdomen, chest, lower back, or groin area. The pain may be severe or dull. Sudden, severe pain in the back or abdomen may mean the aneurysm is about to rupture. This is a life-threatening medical emergency.How long can you have an abdominal aneurysm before it ruptures? ›
The larger an aneurysm is, the greater the chances are that it will rupture. It is estimated that an abdominal aortic aneurysm that is over 5.5 cm in diameter will rupture within one year in about 3 to 6 out of 100 men. That's why surgery is often recommended.Can vascular disease cause stomach problems? ›
Patients with mesenteric artery disease often experience weight loss and severe abdominal pain following meals. Other symptoms include vomiting, dizziness and low blood pressure due to accumulation of acid in the blood.Can vascular problems cause abdominal pain? ›
Abdominal angina is postprandial pain that occurs in mesenteric vascular occlusive disease when blood flow to the colon is unable to meet visceral demands. This is similar to intermittent claudication in peripheral vascular disease or angina pectoris in coronary artery disease.What are the indications for performing an ultrasound evaluation of the abdominal vasculature? ›
Indications for imaging the abdominal vasculature include ruling out neoplastic vascular invasion, determining the presence or absence of suspected congenital vascular anomalies, and identifying intravascular thrombi (e.g., in cases of suspected hypercoagulability).Can abdominal ultrasound show inflammation? ›
This type of ultrasound can detect changes in blood flow through the abdomen. Because the abdomen contains many important body parts, several problems can occur there. Such problems could range from inflammation to abnormal hormonal responses, and they can sometimes indicate the presence of another condition.What are the symptoms of a blocked artery in the stomach? ›
- Sudden belly (abdominal) pain that may be mild, moderate or severe.
- An urgent need to have a bowel movement.
- Frequent, forceful bowel movements.
- Abdominal tenderness or bloating (distention)
- Blood in your stool.
- Nausea and vomiting.
- Mental confusion in older adults.
Numbness, weakness, or heaviness in muscles. Pain (described as burning or aching) at rest, commonly in the toes and at night while lying flat. Paleness when the legs are elevated. Reddish-blue discoloration of the extremities.
What is abnormal vascularity in the stomach? ›
Angiodysplasia is an abnormality with the blood vessels in the gastrointestinal (GI) tract. The GI tract includes the mouth, esophagus, small and large intestines, stomach, and anus. This condition causes swollen or enlarged blood vessels, as well as the formation of bleeding lesions in the colon and stomach.How do you fix vascular problems? ›
- Lifestyle changes, such as eating a heart-healthy diet and getting more exercise.
- Medicines, such as blood pressure medicines, blood thinners, cholesterol medicines, and clot-dissolving drugs. ...
- Non-surgical procedures, such as angioplasty, stenting, and vein ablation.
In many cases, a mild vascular trauma may be able to heal on its own. Doctors treat more severe cases through surgery to repair the damaged vessels.Can vascular problems be cured? ›
There's no cure for peripheral arterial disease (PAD), but lifestyle changes and medicine can help reduce the symptoms. These treatments can also help reduce your risk of developing other types of cardiovascular disease (CVD), such as: coronary heart disease. stroke.Why would I need a vascular ultrasound? ›
Vascular ultrasound is used to evaluate arteries or veins, including blood vessels in the neck, abdomen, arms and legs. It can be performed to: Detect clots in the vein (deep venous thrombosis, or DVT). Confirm chronic venous insufficiency, or leaky valves in the veins that may cause swelling or edema.What are two types of vascular ultrasound exams? ›
There are five different types.
- Carotid ultrasound (carotid duplex) ...
- Aortic ultrasound. ...
- Renal artery ultrasound. ...
- Mesenteric arterial duplex tests.
Vascular problems can impact your quality of life and mobility, cause pain and even be life-threatening. Vascular tests, also called vascular studies, help us thoroughly assess your condition. The results can identify the treatment that will help you regain your ability to do the things you enjoy.Can bowel problems be seen on ultrasound? ›
Over the past few years, thanks to technological progress in ultrasonography, followed by increasing experience of physicians, intestinal ultrasound has become an important diagnostic tool in the detection of bowel diseases.Can diverticulitis be seen on ultrasound? ›
Studies in the hands of expert bowel sonographers show ultrasound has a sensitivity and specificity of >80% for the diagnosis of diverticulitis.What stomach problems cause inflammation? ›
Inflammatory bowel disease (IBD) is a term for two conditions (Crohn's disease and ulcerative colitis) that are characterized by chronic inflammation of the gastrointestinal (GI) tract. Prolonged inflammation results in damage to the GI tract.