Kidney and Bladder US Mike Ackerley

Kidney Advantage over other modalities? What do you see normally? What can we diagnose?

Advantages Ease with which the extent of the disease can be determined within the kidney for focal disease Ease of assessment of renal pelvic or ureteral dilation when fluid distended The location and relevance of renal mineralization can also be assessed When radiographically ID focal renal pelvic or ureteral mineral opacities and the question of whether hydronephrosis is present Biopsy or fine-needle aspiration can be expedited by ultrasonographic guidance, improving the margin of safety as well.

Normals Length in saggital plane Cortex Medullary Papillae Dog: variable with size of dog Cat: 2.8 – 4.2 cm Cortex In dogs more bright than the liver, but less bright than spleen In cats variable, may be equal brightness to that of liver and approach that of the spleen Medullary Papillae The renal medulla in dogs and cats is less echogenic than the cortex. Arcuate vessels Pelvic recess Renal vessels Renal pelvis If high resolution (7.5 – 10 MHz) transducer is used The echotexture (Brightness) consideration is important for assessing diseases that do not alter the kidney architecture (tubular necrosis, FIP)

Capsule Pelvis Cortex Medulla

Pathology Distension Diuresis: bilaterally symmetrical and usually mild Hydronephrosis: pelvic dilation may become very gross, with only a think rim of surrounding parenchymal tissue (idiopathic, or secondary to ureteric obstruction) Renal calculus: strongly reflective surface with distal acoustic shadowing also present. Chronic pyelonephritis: the pelvis may dilate while the diverticula remain small Renal neoplasia: secondary dilation of the renal pelvis and proximal ureter, or mechanical obstruction of the pelvis Ectopic ureter: due to stenosis of the ureter ending and/or ascending infection Renal pelvic blood clot: following renal biopsy, coagulopathy, bleeding neoplasm, idiopathic renal hemorrhage, or trauma

Hydronephrosis Picture

Hydronephrosis

Pathology Focal parenchymal abnormalities Well circumscribed, anechoic parenchymal lesion Hypoechoic parenchymal lesion Hyperechoic parechymal lesion Heterogeneous/complex parenchymal lesion Medullary rim sign Acoustic shadowing

Pathology Well circumscribed, anechoic parenchymal lesion Thin smooth wall: single or multiple cysts Thick/irregular wall: Cyst Hematoma Abscess neoplasia

Pathology Hypoechoic parenchymal lesion Hyperechoic parenchymal lesion Neoplasia Lymphosarcoma Hyperechoic parenchymal lesion 1º: chondrosarcoma, hemangioma Metastatic: hemangiosarcoma, thyroid adenocarcinoma

Pathology Heterogeneous/ Complex parenchymal lesion Neoplasia Abscess Hematoma Granuloma Acute infarct Polycystic disease

Polycystic Kidneys

Renal Infarct

Pathology Medullary rim sign Normal in cats Nephrocalcinosis Ethylene glycol toxicity Chronic interstitial nephritis Cats - FIP

Pathology Acoustic Shadowing Deep to pelvic fat Renal calculus

Nephrolith

Pathology Diffuse parenchymal abnormalities Increased cortical echogenicity Decreased corticomedullary definition

Pathology Increased cortical echogenicity Normal cats Inflammatory disease Glomerulonephritis Interstitial nephritis FIP Acute tubular necrosis/nephrosis (toxins) Renal dysplasia Nephrocalcinosis Neoplasia Diffuse lymphosarcoma

Pathology Decreased corticomedullary definition End-stage kidneys Multiple small cysts

What can we diagnose? Infarcts Cysts/Abscess/Hematoma Renal calculus Big neoplasia Pelvic Dilation

Bladder Advantage over other modalities? What do you see normally? What can we diagnose?

Advantages Able to evaluate bladder wall thickness Able to visualize non-radiopaque stones/cyrstals (C U) Cystocentesis

Normals Best when bladder moderately full Ovoid in shape, with slight elongation caudally at trigone Don’t normally see ureters Three layers (∆ with size) Mucosa: Hyperechoic Muscular: Hypo- Serosal: Hyper- Normal wall thickness (cat): 1.7 mm ± 0.56 Normal wall thickness (dog): 1.6 mm

Pathology Calculi acoustic shadows are observed deep to calculi that exceed the diameter of the beam. echogenicity and acoustic shadow generation are independent of chemical composition (doesn’t matter struvite VS cystine) Ballottement doesn’t move calculi, but let animal stand and calculi will fall. Helps differentiate from mineralized bladder wall and colonic shadowing

Cystic Calculi

Pathology Gas bubbles Blood clots Crystalline sediment Will float to the top, to differentiate from calculi Blood clots non-shadowing Crystalline sediment Vigorous ballottement Swirling pattern when standing

Blood Clot

Pathology Mural changes Cystitis Neoplasia

Pathology Cystitis Chronic cystitis results in diffuse thickening of the bladder wall bladder wall becomes abnormally hypoechoic, and the normal layering becomes less parallel normal sonographic appearance of the bladder does not rule out the presence of mild or acute cystitis or idiopathic lower urinary tract disease in cats

Chronic Cystitis

Pathology Neoplasia TCC: irregularly shaped, broad-based, hypoechoic masses protruding into the bladder lumen echo pattern depends on if if fibrosis, mineralization, and necrosis have developed An abrupt transition often observed between neoplastic mass & adjacent bladder wall

Neoplasia

Pathology Sonographic appearance of polypoid cystitis, adherent blood clots, and mural hematomas is similar to that of neoplasia Observation of ureter dilation adjacent to the bladder wall mass & focal medial iliac lymphadenopathy tends to support the diagnosis of neoplasia Need aspirate, but must weigh that benefit against the possibility of seeding the needle tract with tumor cells Traumatic catheterization is useful to retrieve cells from the mass

What can we diagnose? Crystalline sediment Calculi Blood clots? Gas