Part of our series on ultrasound evaluation of specific abdominal organs/systems, this article reviews ultrasonography of the urinary tract.
October 6, 2017|
Issue: November/December 2017
Elizabeth Huynh, DVM, is a diagnostic imaging resident and graduate student at University of Florida College of Veterinary Medicine. Her interests include ultrasonography, cross-sectional imaging, and nuclear medicine. She received her DVM from Ross University, finished her clinical year at Ohio State University, and completed a diagnostic imaging internship at Animal Specialty and Emergency Center in Los Angeles, California.
Read Articles Written by Elizabeth Huynh
Clifford R. Berry
Dr. Berry is an adjunct professor of diagnostic imaging at the University of Florida and a clinical assistant professor of diagnostic imaging at North Carolina State University College of Veterinary Medicine. He received his DVM from University of Florida and completed a radiology residency at University of California–Davis. He has a specific interest in diagnostic imaging of the thorax.
Updated October 2022
Read Articles Written by Clifford R. Berry
Welcome to our series of articles on small animal abdominal ultrasonography. The initial articles provided an overview of basic ultrasonography principles and a discussion about how to perform a systematic scan of the abdomen. The rest of the series discusses ultrasound evaluation of specific abdominal organs/systems. This article discusses ultrasonography of the urinary tract.
Read the other small animal abdominal ultrasonography articles published in Today’s Veterinary Practice.
Normal Ultrasonography Features
The kidneys are paired structures located in the retroperitoneal space and surrounded by adipose tissue. Normal kidneys are symmetric in size and shape; they can be oval shaped in cats and bean shaped in dogs.
The cranial pole of the left kidney is adjacent to the greater curvature of the stomach and dorsomedial to the craniodorsal extremity of the spleen (seen cranial and lateral). In dogs, the right kidney is located more cranially than the left kidney and lies within the renal fossa of the caudate lobe of the liver. In cats, the right kidney is often separated from the caudate lobe of the liver by retroperitoneal fat.
The widely accepted normal ultrasonographic measurement for kidneys in a cat varies between 3 and 4.3 cm in length. One report proposed that feline kidneys can measure 3.2 to 4.1 cm in length, 2.2 to 2.8 cm in width, and 1.9 to 2.5 cm in height.1
Currently, there is no widely accepted method for determining ultrasonographically normal kidney size for dogs. Ultrasonographic size is usually subjective. The following are proposed methods of measuring normal canine kidney size that have been discussed in recent reports:
- The ratio of the left and right kidney to the length of L5 or L6, with normal being 1.3 to 2.72
- The ratio of kidney length to aortic diameter, with normal ranging from 5.5 to 9.13
When viewing the kidneys in sagittal orientation, the renal sinus, medulla, and cortex can be identified. The renal medulla is the least echogenic region, followed by the renal cortex, and then the renal sinus with hyperechoic fat (Figure 1).4 When assessing for changes of the renal parenchyma, the corticomedullary distinction should be readily identified. At the corticomedullary junction, the interarcuate vessels can be identified normally in some dogs and cats.
The normal renal cortex in dogs can be slightly hyperechoic to the liver.5 In normal cats, however, it is not unusual for the renal cortices to be isoechoic or hyperechoic to the hepatic parenchyma. The renal medulla is homogeneous but often has a coarser echotexture than the renal cortex.
The renal vessels (artery and vein) can be seen entering the renal hilum. Within the renal hilum, extending into the renal sinus, fat can be deposited (hyperechoic), especially in cats. Normally, the renal pelvis is not dilated, but a small amount of anechoic fluid can occasionally be seen; in the transverse plane, the pelvic width can measure up to 2 mm in dogs and 1.6 mm in cats.6
FIGURE 1. Imaging planes of the left kidney in a dog: (A) long axis dorsal, (B) long axis sagittal, (C) short axis transverse. Imaging planes of the left kidney in a cat: (D) long axis dorsal, (E) long axis sagittal, (F) short axis transverse. The different parts of the kidney are labeled in each image. The renal cortex is equal in thickness with the renal medulla and is hyperechoic relative to the renal medulla.
The proximal and mid portions of the ureters extend along the retroperitoneal space lateral to the aorta and caudal vena cava. When examining the urinary bladder, the distal ureters, if seen, can be evaluated as they enter the ureteral papillae in the region of the trigone. Ureteral jets into the bladder lumen can often be detected when scanning the area of the papillae, and detection of the jet may be enhanced by use of color Doppler.
To optimize images of the urinary tract, the patient’s hair must be clipped and ultrasonic gel applied to the skin before examination.
As discussed in “A Tour of the Abdomen: Part 1” (January/February 2016), the urinary tract is examined in a clockwise fashion, beginning with the left kidney, urinary bladder, proximal urethra, and then right kidney. Each kidney is evaluated in its long and short axis; these often correspond to the long and short axis of the patient, although, in some cases, the kidneys are oriented obliquely relative to the patient’s sagittal and transverse planes, requiring some adjustment of the ultrasound imaging plane to obtain true renal sagittal and transverse images.
There are 3 renal imaging planes: 2 long axis (dorsal and sagittal) and 1 short axis (transverse).
Within the dorsal plane (Figure 1), the renal pelvis is located in the far field of the image, and within the sagittal plane, the long axis of the kidney is seen but the renal pelvis is not. Typically, imaging the kidney from the lateral abdominal wall creates the dorsal plane, and imaging the kidney from the ventral aspect of the abdomen creates the sagittal plane.
The transverse plane can be created by rotating the transducer 90°. Mild renal pelvic dilation is usually best seen in the transverse plane when centered on the renal hilum.
Be sure to evaluate each kidney from medial to lateral or dorsal to ventral in one of the long axis imaging planes and from cranial to caudal in the transverse imaging plane. Any abnormalities should be documented with static images or short video clips.
The left kidney is easier to localize than the right kidney because of its lateral location along the mid abdomen. Occasionally, it is seen deep to the spleen (located in the near field). The transducer is initially placed in the left cranial abdomen and is moved medially and caudally until the left kidney is visible in a long axis.
The right kidney is typically more difficult to image due to its craniodorsal location in the abdomen in dogs; it is especially difficult in deep-chested dogs. The transducer is placed in the right dorsolateral subcostal region to visualize the right kidney. However, a lateral approach through the 11th or 12th intercostal space might be needed, especially in deep-chested dogs.
The presence of gas and gastrointestinal contents within the stomach, descending duodenum, and/or the ascending colon can affect the image of the right kidney.7
Urinary Tract Abnormalities
Congenital Abnormalities of the Kidneys
Renal Agenesis or Hypoplasia
Unilateral renal agenesis is rare, but has been reported in dogs and cats.8 If only one kidney exists, compensatory hypertrophy of that kidney may occur. In this instance, the kidney is enlarged but retains normal internal architecture.
Congenital Renal Dysplasia
This defect can be hereditary or result from neonatal infection, such as feline panleukopenia virus or canine herpesvirus. Renal dysplasia is defined as the disorganized development of renal parenchyma leading to misshapen and fibrosed kidneys.9 These kidneys can be normal in size or small, irregular, and hyperechoic with reduced corticomedullary distinction.
Congenital malposition of one or both kidneys may occur. The etiology is unknown. Classification is based on the ectopic kidney’s anatomic position: pelvic, iliac, or abdominal.10 Ectopic kidneys are structurally and functionally normal, but they can be abnormally small, and a short ureter may be kinked, predisposing to obstruction, secondary hydronephrosis, or pyelonephritis.11
This congenital condition results in an abnormal vesicoureteral orifice at the urinary papilla and can be bilateral or unilateral. Ectopic ureters is the most common congenital condition causing dilated ureter and renal pelvis.12 It is more common in female dogs. Ectopic ureters may be dilated due to ileus, concurrent infection, or partial obstruction at the point of entry to the urethra or vagina/vestibule.
Autosomal Dominant Polycystic Kidney Disease
This is an inherited disease reported mostly in Persian or Persian-cross cats, cairn terriers, and bull terriers.13,14 Persian cats and bull terriers inherit this disorder as an autosomal dominant trait. In Persian cats, this disease can be detected as early as 6 to 8 weeks of age, but absence of cysts does not preclude development of cysts later on in life.
Ultrasonographically, these cysts are rounded, centrally anechoic, and have smooth, sharply demarcated thin walls with distal acoustic enhancement (Figure 2). The cysts are located in the renal medulla and cortex, but most are within the cortex or at the corticomedullary junction. Occasionally, these cysts may be found in the liver as well as the pancreas.
FIGURE 2. Long axis sagittal image of the left kidney in a ragdoll cat. Multiple smoothly marginated, rounded, anechoic foci with distal acoustic enhancement are seen throughout the entire renal parenchyma (white arrows). These cystic structures are distorting the entire internal architecture of the kidney. The caudal pole of the kidney is indicated by the white arrowhead.
Focal Abnormalities of the Renal Parenchyma
Renal cysts may be solitary or multiple, involving both kidneys.15–17 This condition may be congenital, as explained previously, or acquired. Renal cysts are round to oval in contour and anechoic, and they have smooth, sharply demarcated thin walls with a distinct far wall border and distal acoustic enhancement.
Cysts may deform the renal capsule if they become large enough or if autosomal dominant polycystic kidney disease is present. Also, they can contain internal echoes in association with hemorrhage or necrotic debris. Diagnostic differentials for solitary cysts include hematoma, abscess, and solid or cavitary mass. The presence of cystic lesions of the kidneys in some breeds, such as German shepherds, should raise concern for some neoplasms, such as renal cystadenocarcinoma, which can be associated with cutaneous paraneoplastic fibrotic nodular lesions (nodular dermatofibrosis).18
Renal hematomas typically occur in a young animal with a clotting disorder or recent trauma. They may contain a mixture of anechoic, hypoechoic, and hyperechoic components within the renal cortex or medulla. Differentiation from some neoplastic lesions, such as renal hemangiosarcoma, can be ultrasonographically challenging.
A renal abscess can occur in conjunction with fever and leukocytosis. Abscesses appear as poorly demarcated cavitary lesions that are irregular in contour with internal echoes and sedimentation, and they have variable degrees of distal acoustic enhancement (Figure 3). Typically, the renal pelvis is enlarged.
FIGURE 3. Short axis transverse image of the left kidney in an Alaskan malamute. This renal abscess is located within a portion of the kidney and is irregularly shaped with a thick wall containing anechoic and echogenic fluid (black arrowheads); the hyperechoic component is forming a sediment in the dependent portion of the abscess, causing a fluid-fluid line. More normal renal architecture is still present (white arrow).
Ultrasonographically, organized infarcts are well-defined, wedge-shaped, cortical lesions located perpendicular to the capsule and extending centrally to the renal pelvis (Figure 4). The base of the wedge-shaped lesion is directed toward the renal capsule while the apex points towards the hilus. They vary in appearance and, at the chronic phase, are typically hyperechoic and cause focal cortical depressions secondary to contracture and fibrosis.
FIGURE 4. Long axis sagittal image of the left kidney in a domestic shorthaired cat. A focal, hyperechoic, wedge-shaped, focally concave, renal cortical infarction is seen extending from the cortex to the corticomedullary junction (white arrowheads) along the caudal pole of the kidney.
Renal Mineralization (Nephrocalcinosis)
Renal mineralization can be seen in older dogs and cats. It is classified based on its location. Renal diverticular mineralization is caused by dystrophic mineralization. Renal parenchymal mineralization, however, is caused by mineralization of the renal cortex from deposition of calcium salts or other minerals (eg, ethylene glycol toxicosis).
Mineralization is identified as hyperattenuating foci with distal acoustic shadowing within the renal diverticuli, pelvis, and/or cortex (Figure 5); however, if there are punctate foci of hyperechogenicity, distal acoustic shadowing may not be evident.
FIGURE 5. Long axis sagittal image of the left kidney in a Siamese cat. Overall, the kidney is irregularly shaped, lobulated, and small. There is a large, hyperechoic, smoothly marginated nephrolith with distal acoustic shadowing located within a renal diverticulum (white arrow). Note the renal pelvis distended with anechoic fluid (white arrowhead).
These tumors are commonly found in German shepherds and are associated with paraneoplastic nodular dermatofibrosis (neurofibromas). Ultrasonographically, one to several fluid-filled cavities (cysts) can be detected, and a solid tissue component can infiltrate the kidney and protrude into the cyst.19
Other Renal Neoplasia
Solid soft tissue masses may appear in a variety of ways:
- Homogeneous or heterogeneous
- Hypoechoic, isoechoic, or hyperechoic
- Regular or irregular with variable margins (Figure 6)
- Altered renal internal architecture
- Hypoechoic halo at the periphery of the cortex
- Hyperechoic foci or striations throughout the medulla
- Hypoechoic medullary or cortical nodules or masses20
FIGURE 6. Long axis sagittal image of the right kidney in a Rhodesian ridgeback. There is a large, lobulated, heterogeneous mass located in the cranial pole of the kidney. The margins of this mass are well demarcated (white arrowheads). More normal renal parenchyma can still be identified in the caudal pole of the kidney (white arrow). This mass was diagnosed as a renal cell carcinoma.
The differential diagnosis of hypoechoic nodules or masses includes lymphoma and malignant histiocytosis.21 Other neoplasms that can affect kidneys include adenocarcinomas, hemangiomas, nephroblastomas, hemangiosarcomas, and metastases.22
The most common renal tumor in the dog is renal cell carcinoma (Figures 6 and 7). The most common renal tumor in the cat is renal lymphoma (Figure 8), where diffuse changes can be seen. The kidneys are usually enlarged, irregular, hyperechoic, with hypoechoic subcapsular thickening.23
FIGURE 7. Long axis sagittal image of the left kidney in a Labrador retriever. There is an expansile, well demarcated, lobulated, heterogeneously hyperechoic mass in the caudal pole of the kidney, causing distortion of the renal architecture and shape. This dog was diagnosed with renal cell carcinoma.
FIGURE 8. (A) Long axis sagittal and (B) short axis transverse images of the right kidney in a domestic shorthaired cat. The cortex is thickened and hyperechoic, and its margin is irregular. Anechoic fluid is detected within the mildly to moderately distended renal pelvis (white arrowheads). A very small amount of anechoic to hypoechoic fluid surrounds the kidney (white arrow). This cat was diagnosed with renal lymphoma.
Diffuse Abnormalities of the Renal Parenchyma
Ethylene Glycol Toxicosis
Ethylene glycol toxicosis causes a severe increase in cortical and, to a lesser extent, medullary hyperechogenicity (Table 1). In addition, there can be a medullary rim sign, which is denoted as a circumferential hyperechoic band located in the medulla, parallel to the corticomedullary junction (Figure 9); this appearance is consistent with mineralization, necrosis, congestion, and/or hemorrhage.20
TABLE 1. Differential Diagnoses of Diffuse Renal Cortical and Medullary Hyperechogenicity
[ultimatetables 17 /]
FIGURE 9. Long axis sagittal image of the right kidney in a mixed-breed dog. The renal cortex is severely hyperechoic. There is also a hyperechoic band within the medulla traversing parallel to the corticomedullary junction (white arrows). This dog was diagnosed with ethylene glycol toxicosis.
Caution should be used when interpreting the medullary rim sign; it should not be considered an accurate indicator of renal disease, although it could represent sentinel signs of early renal disease or past renal insult.27 It has also been detected in clinically normal dogs and cats.27,28
Chronic Interstitial Nephritis
Kidneys become small, irregular, and diffusely hyperechoic from fibrosis.16 When kidneys are diffusely hyperechoic, the corticomedullary demarcation becomes difficult to delineate.
Capsular or Pericapsular Disease
Perirenal or Subcapsular Fluid
The differential diagnosis for perirenal or subcapsular fluid includes:
- Urine leakage29
- Acute renal failure29
- Ureteral obstruction29
- Ethylene glycol toxicosis29
Perinephric (Perirenal) Pseudocysts
Ultrasonographically, perirenal pseudocysts appear as an accumulation of anechoic fluid around one or both kidneys, most commonly between the capsule and the renal cortex (Figure 10).32 Subscapular perirenal pseudocysts are formed by accumulation of a transudate between the capsule and parenchyma of the kidney due to underlying parenchymal disease.32 This is more common in cats.
FIGURE 10. Long axis sagittal image of the right kidney in a domestic shorthaired cat. The kidney is abnormally shaped, lobulated, and contains multiple hyperechoic, wedge-shaped defects within its cortical margin. The diverticuli contains multiple ovoid, hyperechoic foci (black arrowheads) with distal acoustic shadowing. There is a large amount of anechoic fluid surrounding the kidney, consistent with a perinephric pseudocyst (white arrows).
Abnormalities of the Renal Pelvis and Proximal Ureter
Pyelectasia is a dilation of the renal pelvis (Figure 11).33 Pyelectasia may be caused by intravenous fluid administration, diuretic administration, increased diuresis from renal insufficiency, distended urinary bladder or lower urinary tract obstruction, pyelonephritis, ureteritis, ectopic ureter, or another congenital malformation.
FIGURE 11. Short axis transverse image of the right kidney in a domestic shorthaired cat. The retroperitoneal fat is hyperechoic. There is poor corticomedullary distinction. The renal pelvis is mildly distended with slightly echogenic fluid. This cat was diagnosed with presumptive pyelonephritis.
Pyelonephritis can affect one or both kidneys and is usually a result of ascending ureteral infection from the urinary bladder. Ultrasonographic changes associated with pyelonephritis include:
- Mild renal enlargement and mild to moderate pelvic and ureteral dilation34
- Hyperechoic mucosal margin parallel to the wall of the renal pelvis and proximal ureter24
- Echogenic medullary band at the corticomedullary junction
- Focal hyperechoic areas in the renal medulla and patchy, focal hypoechoic or hyperechoic areas in the renal cortex24
Urine echogenicity may increase and even contain sedimentation due to pyuria. In chronic cases, renal pelvic and diverticula distortion and a hyperechoic rim can be seen.
Hydronephrosis occurs when the renal pelvis and diverticuli become dilated, distorting and compressing the renal parenchyma.33 The renal diverticuli become rounded and appear as anechoic finger-like projections extending from the anechoic renal pelvis (Figure 12).
FIGURE 12. Long axis sagittal image of the left kidney in a domestic shorthaired cat. The renal pelvis (P) and proximal ureter (U) are moderately distended with anechoic fluid. Note the rounded renal diverticuli (white arrowheads). This cat was diagnosed with obstructive hydronephrosis and hydroureter secondary to ureteral calculi.
Possible causes of hydronephrosis include congenital malformation, lower urinary tract obstruction, and ureteral or renal pelvic obstruction from a calculus, stricture, or trigonal or retroperitoneal mass.
In chronic cases, the renal pelvis is distended, and the renal parenchyma can atrophy. Hydroureter is often seen in combination with hydronephrosis. Hydronephrosis may progress to pyonephrosis, caused by urinary stasis and subsequent infection.35
If ureters are filled with fluid, they are easily identified beginning at the renal hilus. Ureters can be abnormally distended secondary to ectopia, ureteritis, obstruction, or congenital conditions.36
In chronic obstructions, the distended ureters can become severely enlarged and tortuous, making it possible to follow them caudally to the level of the obstruction. If ureteroliths (ureteral calculi) are suspected to be the inciting cause, smoothly to irregularly marginated, hyperechoic foci with distal acoustic shadowing can be identified within the abnormally distended ureteral lumen.
Other tubular structures are also located in the renal hilus, such as the renal vein and artery. To differentiate hydroureter from a normal renal vessel, color Doppler or power Doppler can be used, focusing on the renal hilum (Figure 13); the anechoic tubular structures with flow within their lumen are vascular and should not be mistaken for the abnormally distended ureter.
FIGURE 13. Long axis sagittal image of the right ureter at the level of the apex of the urinary bladder in a domestic shorthaired cat. The ureter is distended with anechoic fluid. Note the lack of color Doppler flow within the ureter and the subjectively thickened ureteral wall.
Abnormalities of the Retroperitoneum
Retroperitoneal transudate appears as linear, triangular, or oval anechoic to hypoechoic foci adjacent to the kidneys. These changes can be seen with accumulation of urine or blood, following trauma to the kidneys and/or ureters.
Retroperitoneal exudate and acute hemorrhage are usually more echogenic because of their higher cell count. Inflammatory processes, such as acute pyelonephritis and ureteritis, can cause the retroperitoneal fat to become hyperechoic and hyperattenuating.
Retroperitoneal abscesses can be caused by migrating plant awns in some regions of the country. They have thickened, irregular walls and often present as anechoic to hypoechoic masses, with or without septae and internal echogenic debris.37
Retroperitoneal masses may occur secondary to granulomas, neoplasia, or enlarged sublumbar lymph nodes. They can be variable in size, shape, and echogenicity. Hemangiosarcoma is a common neoplasm of the canine retroperitoneal space (Figure 14).38
FIGURE 14. Long axis sagittal image of the right retroperitoneal space in an Australian shepherd. There is an irregularly shaped, heterogeneous mass with anechoic foci (white arrowhead) within the retroperitoneal space. The crosshairs demarcate the peripheral extremities of this mass in this view. A malignant neoplasm, such as hemangiosarcoma, was highly suspected; however, no cytology or histopathology was performed to confirm this suspicion.
Abnormalities of the kidneys and ureters are commonly seen when urinary bladder abnormalities are present. A systematic examination of the urinary system is a routine part of the complete abdominal evaluation.
- Walter PA, Feeney DA, Johnston GR, Fletcher TF. Feline renal ultrasonography: quantitative analyses of imaged anatomy. Am J Vet Res 1987;48(4):596-599.
- Barella G, Lodi M, Sabbadin LA, Faverzani S. A new method for ultrasonographic measurement of kidney size in healthy dogs. J Ultrasound 2012;15(3):186-191.
- Mareschal A, d’Anjou MA, Moreau M, et al. Ultrasonographic measurement of kidney-to-aorta ratio as a method of estimating renal size in dogs. Vet Radiol Ultrasound 2007;48(5):434-438.
- Hart DV, Winter MD, Conway J, Berry CR. Ultrasound appearance of the outer medulla in dogs without renal dysfunction. Vet Radiol Ultrasound 2013;54(6):652-658.
- Ivancic M, Mai W. Qualitative and quantitative comparison of renal vs. hepatic ultrasonographic intensity in healthy dogs. Vet Radiol Ultrasound 2008;49(4):368-373.
- D’Anjou MA, Bedard A, Dunn ME. Clinical significance of renal pelvic dilatation on ultrasound in dogs and cats. Vet Radiol Ultrasound 2011;52(1):88-94.
- Nyland TG, Widmer WR, Mattoon JS. Urinary tract. In: Mattoon JS, Nyland TG, ed. Small Animal Diagnostic Ultrasound. 3rd ed. St. Louis: Elsevier Saunders; 2015:557-607.
- Hoskins JD. The Urinary System. In: Hoskins JD, ed. Veterinary Pediatrics: Dogs and Cats from Birth to Six Months. 3rd ed. Philadelphia: Saunders; 2001:371-395.
- Burder MC, Shoieb AM, Shirai N, et al. Renal dysplasia in beagle dogs: four cases. Toxicol Pathol 2010;38(7):1051-1057.
- Allworth MS, Hoffmann KL. Crossed renal ectopia with fusion in a cat. Vet Radiol Ultrasound 1999;40(4):357-360.
- Hecht S. Diagnostic imaging of lower urinary tract disease. Vet Clin North Am Small Anim Pract 2015;45(4):639-663.
- Lamb CR, Gregory SP. Ultrasonographic findings in 14 dogs with ectopic ureter. Vet Radiol Ultrasound 1998;39(3):218-223.
- Reichle JK, DiBartola SP, Leveille R. Renal ultrasonographic evaluation and computed tomographic appearance, volume, and function of cats with autosomal dominant polycystic kidney disease. Vet Radiol Ultrasound 2002;43(4):368-373.
- McKenna SC, Carpenter JL. Polycystic disease of the kidney and liver in the Cairn Terrier. Vet Pathol 1980;17(4):436-442.
- Konde LJ. Sonography of the kidney. Vet Clin North Am Small Anim Pract 1985;15(6):1149-1158.
- Walter PA, Feeney DA, Johnston GR, O’Leary TP. Ultrasonographic evaluation of renal parenchymal diseases in dogs: 32 cases (1981- 1986). JAVMA 1987;191(8):999-1007.
- Walter PA, Johnston GR, Feeney DA, O’Brian TD. Applications of ultrasonography in the diagnosis of parenchymal kidney disease in cats: 24 cases (1981-1986). JAVMA 1988;192(1):92-98.
- Lium B, Moe L. Hereditary multifocal renal cystadenocarcinomas and nodular dermatofibrosis in the German shepherd dog: macroscopic and histopathologic changes. Vet Pathol 1985;22(5):447-455.
- Moe L, Lium B. Hereditary multifocal renal cystadenocarcinomas and nodular dermatofibrosis in 51 German shepherd dogs. J Small Anim Pract 1997;38(11):498-505.
- Konde LJ, Wrigley RH, Park RD, Lebel JL. Sonographic appearance of renal neoplasia in the dog. Vet Radiol Ultrasound 1985;26(3):74-81.
- Taylor AJ, Lara-Garcia A, Benigni L. Ultrasonographic characteristics of canine renal lymphoma. Vet Radiol Ultrasound 2014;55(4):441-446.
- Bryan JN, Henry CJ, Turnquist SE, et al. Primary renal neoplasia of dogs. J Vet Intern Med 2006;20(5):1155-1160.
- Valdes-Martinez A, Cianciolo R, Mai W. Association between renal hypoechoic subcapsular thickening and lymphosarcoma in cats. Vet Radiol Ultrasound 2007;48(4):357-360.
- Neuwirth L, Mahaffey M, Crowell W, et al. Comparison of excretory urography and ultrasonography for detection of experimentally induced pyelonephritis in dogs. Am J Vet Res 1993;54(5):660-669.
- Adams WH, Toal RL, Breider MA. Ultrasonographic findings in dogs and cats with oxalate nephrosis attributed to ethylene glycol intoxication: 15 cases (1984-1988). JAVMA 1991;199(4):492-496.
- Chandler ML, Elwood C, Murphy KF, et al. Juvenile nephropathy in 37 boxer dogs. J Small Anim Pract 2007;48(12):690-694.
- Mantis P, Lamb CR. Most dogs with medullar rim sign on ultrasonography have no demonstratable renal dysfunction. Vet Radiol Ultrasound 2000;41(2):164-166.
- Yeager AE, Anderson WI. Study association between histologic features and echogenicity of architecturally normal cat kidneys. Am J Vet Res 1989;50(6):860-863.
- Holloway A, O’Brien R. Perirenal effusion in dogs and cats with acute renal failure. Vet Radiol Ultrasound 2007;48(6):574-579.
- Whittemore JC, Preston CA, Kyles AE, et al. Nontraumatic rupture of an adrenal gland tumor causing intra-abdominal or retroperitoneal hemorrhage in four dogs. JAVMA 2001;219(3):324, 329-333.
- HyeYeon L, JinHwa C, JooHyun J, et al. Unilateral renal subcapsular abscess associated with pyelonephritis in a cat. J Vet Clin 2010;27:79- 82.
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- Choi J, Jang J, Choi H, et al. Ultrasonographic features of pyonephrosis in dogs. Vet Radiol Ultrasound 2010;51(5):548-553.
- Lamb CR. Ultrasonography of the ureters. Vet Clin North Am Small Anim Pract 1998;28(4):823-848.
- Hylands R. Veterinary diagnostic imaging. Retroperitoneal abscess and regional cellulitis secondary to a pyelonephritis within the left kidney. Can Vet J 2006;47(10):1033-1035.
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A kidney ultrasound may be used to assess the size, location, and shape of the kidneys and related structures, such as the ureters and bladder. Ultrasound can detect cysts, tumors, abscesses, obstructions, fluid collection, and infection within or around the kidneys.What is ultrasonography of the kidneys called? ›
When ultrasound is used to look at the kidneys or bladder, it's called a renal ultrasound.What does a urinary tract ultrasound show? ›
Bladder ultrasound can give information about the bladder wall, diverticula (pouches) of the bladder, bladder stones, and large tumors in the bladder. Kidney ultrasound can show if the kidneys are in the right place or if they have blockages, kidney stones, or tumors.What is the sonographic appearance of the kidneys? ›
Each kidney is surrounded by a renal capsule which appears as a thin, hyperechoic line when observed in perpendicular orientation relative to the ultrasound beam. The outer renal cortex has a fine and uniform echotexture.
The primary requirement is to drink at least 24 ounces of a clear liquid an hour or more before the procedure. This is because a kidney ultrasound is also a bladder ultrasound and your physician will want images of your bladder both before and after you empty it. There is no fasting requirement for a renal ultrasound.What are the first signs of kidney problems? ›
- weight loss and poor appetite.
- swollen ankles, feet or hands – as a result of water retention (oedema)
- shortness of breath.
- blood in your pee (urine)
- an increased need to pee – particularly at night.
- difficulty sleeping (insomnia)
- itchy skin.
A kidney and bladder ultrasound, or renal ultrasound, uses high frequency sound waves to visualize and assess your kidneys, ureters (small muscular tubes that join the kidneys with the bladder) and urinary bladder.What is another name for kidney scan? ›
The medical term for a kidney scan is renal scintigraphy. Your healthcare provider injects small amounts of radioactive material (radioisotope or tracer) into your vein. You'll pass through a scanner, which locates the radioactive material in your kidneys and sends images to a computer.Is ultrasound of kidney same as CT scan? ›
A CT scan uses x-rays and computers to create three dimensional pictures of your urinary tract (kidneys, ureters, and bladder). An ultrasound uses sound waves to create a picture of your kidneys and bladder. It is like the ultrasound used to look at the baby in the womb of a pregnant woman.How long does a urinary tract ultrasound take? ›
The procedure lasts between 10 and 20 minutes. Occasionally, especially if the bladder is not filled, you may be asked to drink more water and wait until the bladder fills. More images can then be taken to complete the examination. When do I get the results?
Empty your bladder one to two hours before the ultrasound. Drink one liter or 32 ounces of water 30 minutes before your ultrasound appointment. Don't empty your bladder again until the appointment ends.How do doctors check if you have a urinary tract infection? ›
UTIs can be found by analyzing a urine sample. The urine is examined under a microscope for bacteria or white blood cells, which are signs of infection. Your health care provider may also take a urine culture. This test examines urine to detect and identify bacteria and yeast, which may be causing a UTI.Can you see kidney failure on an ultrasound? ›
So, to the question of whether an ultrasound can tell if you have kidney failure, the answer is: Yes. Depending on the case, it may be necessary to apply only ultrasound or other techniques to confirm the diagnosis.Can an ultrasound show kidney problems? ›
Specifically, an ultrasound on the kidneys can evaluate a patient's kidney health. By doing so, a doctor can determine if there are any present abnormalities in the kidneys. The ultrasound results allow them to properly diagnose kidney disease—if present in the body. Moreover, an ultrasound is a non-invasive procedure.How do you prepare for a kidney ultrasound? ›
This exam requires little to no special preparation. The ultrasound technologist may ask you to drink water before the exam to fill your bladder. Leave jewelry at home and wear loose, comfortable clothing. You may need to wear a gown.Do you have to undress for a renal ultrasound? ›
You will not need to undress for the exam. You will be asked to lie down. Your shirt is then pulled up to expose the abdomen and towels are used to protect your clothing from the ultrasound gel. Ultrasound gel is water-based and does not harm the skin or clothing.How long does an ultrasound of the kidneys take? ›
A kidney ultrasound takes about 20-30 minutes.Do you lay on your back for a kidney ultrasound? ›
Your procedure will be performed with you lying on the examination table on your back. The technologist may ask you to turn on your side to get a better view of your kidneys. The technologist will apply warm gel to your abdomen.What is red flags in kidney disease? ›
Reduced GFR is a red flag for six major complications in patients with CKD: acute kidney injury risk, resistant hypertension, metabolic abnormalities, adverse drug reactions, accelerated cardiovascular disease and progression to end-stage kidney disease.Where do you itch with kidney disease? ›
Itching from kidney disease can be anywhere on the body. People with uremic pruritus tend to be itchy on their face, back, and arms.
Signs and symptoms of Stage 1 CKD include: High blood pressure. Swelling in your hands or feet. Urinary tract infections.What happens if you don t drink enough water before ultrasound? ›
So Why Is it So Important to Drink Water Before an Ultrasound? Dehydration can cause your urine to be concentrated, which can lead to inaccurate results. In addition, dehydration can also cause the liver to produce less bile, which can make it more difficult to see the gallbladder on an ultrasound.What does a dark spot on a kidney ultrasound mean? ›
Benign cysts in the kidneys tend to appear as black spots on an ultrasound because the waves pass through them and don't bounce back. The care team can explain the potential implications of any light or dark spots revealed by an imaging scan.What if I can't hold my pee before an ultrasound? ›
If you have trouble keeping your bladder full, you may be asked to empty your bladder about an hour before your exam and then drink water once you get to the radiologist's office so that the test can be done immediately after your bladder is filled.What is the most accurate test for kidney function? ›
Blood test: eGFR
eGFR (estimated glomerular filtration rate) is a measure of how well your kidneys are working. Your eGFR is an estimated number based on a blood test and your age, sex, body type and race. eGFR is considered a mostly reliable test for doctors to know how well your kidneys are working.
CT scans of the kidneys can provide more detailed information about the kidneys than standard kidney, ureter, and bladder (KUB) X-rays , thus providing more information related to injuries and/or diseases of the kidneys.What is the best scan for kidneys? ›
CT scan is the preferred test to detect renal infections as it can help in identifying gas, stones, calcifications (stone-like calcium deposits) within the kidney, bleeding, abscesses and obstruction. CT scan is the best way to assess for stone disease.Can ultrasound detect kidney tumor? ›
Today, most kidney tumors are found incidentally during imaging studies such as ultrasound, CT scan or MRI. While some small tumors are destined to stay small and not cause harm, others can have aggressive behavior and earlier detection improves outcome.What can mimic kidney stone pain? ›
Kidney stones are sometimes considered "the great mimicker" because their signs and symptoms are very similar to appendicitis, ovarian or testicular conditions, gastritis, and urinary tract infections.Why would a urologist order a CT scan? ›
Why it's done. A CT urogram is used to examine the kidneys, ureters and bladder. It lets your doctor see the size and shape of these structures to determine if they're working properly and to look for any signs of disease that may affect your urinary system.
One hour before your appointment please drink 2 pints of fluid, preferably water (not milk or fizzy drinks). Try not to empty your bladder after this. If you are worried about travelling with a full bladder, please arrive one hour prior to your appointment time and water will be provided for you to drink.Why do they make you pee before an ultrasound? ›
We ask you to do this because in a first-trimester ultrasound, a full bladder acts like a window into the uterus.Do you need a full bladder for a kidney scan? ›
In order for the scan to be successful, it is necessary for you to have a very full bladder. We recommend that you drink at least two pints of water about 1 hour before the appointment time and then refrain from emptying your bladder in order to achieve this.Will a sonographer tell you if something is wrong? ›
In most cases, the sonographer or sonologist can view the image on the screen and have a pretty good idea of what's happening in there. Sometimes they will tell you right then and there and other times you have to wait to have your GP explain it especially if you have to have further testing to clarify findings.Do they tell you results of ultrasound scan straight away? ›
You may be told the results of your scan soon after it's been carried out, but in most cases the images will need to be analysed and a report will be sent to the doctor who referred you for the scan. They'll discuss the results with you a few days later or at your next appointment, if one's been arranged.How much water should you drink before a bladder ultrasound? ›
❑ Pelvic, Bladder
You will need to finish drinking 28 to 32 ounces of water 1 hour before your exam so you have a full bladder. Do not urinate before the exam.
- Pain or burning while urinating.
- Frequent urination.
- Feeling the need to urinate despite having an empty bladder.
- Bloody urine.
- Pressure or cramping in the groin or lower abdomen.
Bladder infections are a type of UTI, but not all urinary tract infections are bladder infections. A UTI is defined as an infection in one or more places in the urinary tract—the ureters, kidneys, urethra, and/or bladder. A bladder infection is a UTI that's only located in the bladder.How does a doctor know if you have a UTI or kidney infection? ›
The most common lab tests to help diagnose a kidney infection are two types of urine test: Urinalysis For this test, you'll urinate into a container at your doctor's office or lab. A sample of your urine will be viewed under a microscope, to look for bacteria or white blood cells, which can indicate an infection.What color is urine when your kidneys are failing? ›
When your kidneys are failing, a high concentration and accumulation of substances lead to brown, red, or purple urine. Studies suggest the urine color is due to abnormal protein or sugar as well as high numbers of cellular casts and red and white blood cells.
Hydronephrosis is usually diagnosed using an ultrasound scan. Further tests may be needed to find out the cause of the condition. An ultrasound scan uses sound waves to create a picture of the inside of your kidneys. If your kidneys are swollen, this should show up clearly.What can be mistaken for kidney failure? ›
Muscle-wasting disease or a neuromuscular disorder. Those suffering from malnutrition, eating a vegetarian or low-meat diet, or taking creatinine dietary supplements.What are the signs that something is wrong with your kidneys? ›
- Loss of appetite.
- Fatigue and weakness.
- Sleep problems.
- Urinating more or less.
- Decreased mental sharpness.
- Muscle cramps.
Blood Tests. Because your kidneys remove waste, toxins, and extra fluid from the blood, a doctor will also use a blood test to check your kidney function. The blood tests will show how well your kidneys are doing their job and how quickly the waste is being removed.What is the main cause of kidney failure? ›
What causes kidney failure? High blood pressure and diabetes are the two most common causes of kidney failure. They can also become damaged from physical injury, diseases, or other disorders.What are they looking for in a kidney and bladder ultrasound? ›
Bladder ultrasound can give information about the bladder wall, diverticula (pouches) of the bladder, bladder stones, and large tumors in the bladder. Kidney ultrasound can show if the kidneys are in the right place or if they have blockages, kidney stones, or tumors.How accurate is a kidney ultrasound? ›
In a retrospective evaluation of 136 proved cases renal ultrasonography was 95 per cent accurate in distinguishing normal from pathological renal masses, 85 per cent accurate in diagnosing uncomplicated cysts and 100 per cent accurate in identifying complicated cysts, polycystic disease, extrarenal lesions and solid or ...How is kidney ureter bladder ultrasound done? ›
A renal (REE-nul) ultrasound uses sound waves to make images of the kidneys, ureters, and bladder. During the scan, an ultrasound machine sends sound waves into the kidney area and images are recorded on a computer. The black-and-white images show the internal structure of the kidneys and related organs.How do you prepare for a kidney ureter bladder ultrasound? ›
What preparation is required for the a KUB Ultrasound scan? A full bladder is required and you will need to drink a pint of water in the hour before your scan. During this period, please do not empty your bladder.Can an ultrasound tell if your kidneys are failing? ›
Specifically, an ultrasound on the kidneys can evaluate a patient's kidney health. By doing so, a doctor can determine if there are any present abnormalities in the kidneys. The ultrasound results allow them to properly diagnose kidney disease—if present in the body. Moreover, an ultrasound is a non-invasive procedure.
If you have trouble keeping your bladder full, you may be asked to empty your bladder about an hour before your exam and then drink water once you get to the radiologist's office so that the test can be done immediately after your bladder is filled.What if I need to pee before my ultrasound? ›
Don't urinate (pee) before your ultrasound. Having a full bladder will make it easier to see your uterus and ovaries. If close-up views of the lining of your uterus and your ovaries are needed, you may have a transvaginal ultrasound after your pelvic ultrasound.How can a doctor tell if something is wrong with your kidneys? ›
Blood Tests. Because your kidneys remove waste, toxins, and extra fluid from the blood, a doctor will also use a blood test to check your kidney function. The blood tests will show how well your kidneys are doing their job and how quickly the waste is being removed.Why would a doctor order a kidney ultrasound? ›
For both men and women, this exam can help detect fluid collection, kidney or urinary tract infection, cysts, tumors, kidney disease, obstructions like kidney stones, and more. While the severity of bladder and kidney conditions vary, many of them are very common.How do you treat a non functioning kidney? ›
If you have kidney failure, your kidneys no longer work effectively. It's fatal without proper treatment. Dialysis or a kidney transplant can help you continue to live a long life. Your treatment plan may also include taking medications and following a special diet.