Radiology3- Kidneys and Ureters

  1. What is the location and size of normal kidneys on radiographs?
    • Location: retroperitoneal, right more cranial than left (esp in dogs)
    • Size in dogs: 2.5-3.5 x length of L2
    • Size in cats: 2-3x length of L2
  2. The size of the kidneys can only be accurately evaluated on...
    VD view!
  3. Describe normal margination of small animal kidneys and why the margins are seen.
    • should have smooth margins in dogs and cats
    • margins are seen due to contrast with retroperitoneal fat
  4. What are causes of lack of visualization of the kidney(s)? (4)
    • border effacement/ superimposition with GI structures
    • retroperitoneal effusion or lack of retroperitoneal fat 
    • surgical removal of a kidney
    • renal aplasia or agenesis
  5. What are general indications of excretory urogram (intravenous pyelogram)?
    • better evaluation of the kidneys (increases contrast with surrounding tissues)- structural change s (cysts, masses, nephroliths, hematoma), qulitative assessment of renal function
    • evaluate ureters (not normally seen)- ureteroliths, structures, tears, ectopic ureters
  6. If an animal is azotemic, how do you alter your IV dose of iodinated contrast for excretory urogram?
    increase dose
  7. Why might you perform a concurrent negative contrast cystogram with an excretory urogram?
    to better visualize the uretero-vesicular junction, dx ectopic ureters
  8. What are contraindications for excretory urogram? (2)
    • dehydration (rehydrate first)
    • previous reaction to contrast
  9. What are potential complications with excretory urogram? (4)
    • contrast induced renal failure has been reported, usually reversible with diuresis
    • anaphylactic reaction
    • nausea/ vomiting
    • IV contrast may cause transient CV changes
  10. Why should you obtain a urine sample and perform a UA before performing an excretory urogram? (2)
    • iodinated contrast limits bacterial growth (possible false neg culture)
    • iodinated contrast can affect the specific gravity
  11. Describe the vascular phase of an excretory urogram. (2)
    • occurs immediately post-injection of contrast
    • allows you to identify the renal artery(ies) supplying the kidney
  12. Describe the nephrogram phase of an excretory urogram. (3)
    • occurs immediately post-injection of contrast
    • parenchyma most opaque ~10-30s pst-injection
    • can eval tubules and vascular supply
  13. Describe the pyelogram phase of an excretory urogram. (3)
    • occurs 1-2 minutes after the injection
    • can eval pelvis, renal diverticula, ureters
    • ureters are intermittently opacified
  14. How wide should the renal pelvis and ureters be on an excretory urogram?
    • Pelvis= 1-2mm wide
    • Ureters= 2-3mm wide
  15. How do normal ureters appear at their insertion to the bladder?
    "J" hook at the trigone
  16. What are causes of renomegaly? (7)
    • neoplasia (smooth or irregular margins)
    • hematoma (usually unilateral)
    • perinephric pseudocysts (smooth margins, CATS)
    • nephritis/ pyelonephritis
    • hydronephrosis (smooth margins)
    • hypertrophy
    • chronic renal disease (BKLK) (smooth or irregular margins)
  17. What are potential causes of small kidney(s)? (2)
    • chronic renal disease (smooth or irregular margins)
    • renal hypoplasia
  18. Describe the appearance an clinical aspects of perinephric pseudocysts. (4)
    • enlarged kidneys
    • smooth margins
    • other DDx- nephritis, hydronephrosis, infiltrative neoplasia
  19. What are causes of a change in shape of the kidney(s)?
    chronic infarcts
  20. What are potential causes of renal pelvic dilation? (3)
    • obstruction (ureteroliths)
    • diuresis
    • pyelonephritis
  21. What are potential causes of an increase in opacity of the kidney(s)? (3)
    • nephrolith(s)
    • dystrophic mineralization of parenchyma
    • mineralization of cyst, tumor, granuloma, hematoma
  22. What are potential causes of a decrease in opacity of the kidney(s)? (2)
    • vesico-ureteral reflux after negative contrast cystogram
    • taruma
  23. What are radiographic aspects of pyelonephritis? (3)
    • pelvic dilation
    • proximal ureteral dilation
    • blunted pelvic recesses
  24. What are radiographic aspects of hydronephrosis? (5)
    • pelvic dilation
    • dilation of pelvic recesses (right)
    • pelvic recesses not seen (left)
    • ureteral dilation
    • if severe, renomegaly
  25. What are radiographic aspects of renal neoplasia? (3)
    • mass effect in caudal pole
    • distortion of renal pelvis
    • other DDx- renal cyst
  26. What are causes of renal pelvic filling defects on urogram? (3)
    • blood clot
    • calculi (remember:calculi will appear radiolucent when surrounded by positive contrast)
    • neoplasia
  27. What are causes of diffuse ureteral enlargement? (3)
    • obstructive hydroureter
    • atony secondary to inflammation
    • unilateral- ectopic ureter
  28. What are causes of a focal ureteral enlargement? (1)
    ureteroceole (congenital defect- ureter balloons distally before it enters bladder)
  29. How might an ectopic ureter appear on excretory urogram?
    • abnormal accumulation of positive contrast in the vagina
    • hydroureter
  30. What are the subsets of ureteral luminal filling defects and causes of each? (3)
    • intraluminal (contrast going around defect): calculi, gas bubble, blood clot
    • intramural (irregular wall margin): neoplasia, inflammation, granuloma
    • extraluminal-extramural (external compression): stricture, external mass
Card Set
Radiology3- Kidneys and Ureters
vetmed radiology3