Kidney and Bladder US

1. Kidney and Bladder US Mike Ackerley

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

3. 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.

4. Normals • Length in saggital plane • 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

5. Capsule Pelvis Cortex Medulla

6. 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

7. Hydronephrosis

8. Hydronephrosis

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

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

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

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

13. Polycystic Kidneys

14. Renal Infarct

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

16. Pathology • Acoustic Shadowing • Deep to pelvic fat • Renal calculus

17. Nephrolith

18. Pathology • Diffuse parenchymal abnormalities • Increased cortical echogenicity • Decreased corticomedullary definition

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

20. Pathology • Decreased corticomedullary definition • End-stage kidneys • Multiple small cysts

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

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

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

24. 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

25. 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

26. Cystic Calculi

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

28. Blood Clot

29. Pathology • Mural changes • Cystitis • Neoplasia

30. 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

31. Chronic Cystitis

32. 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

33. Neoplasia

34. 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

35. What can we diagnose? • Crystalline sediment • Calculi • Blood clots? • Gas