Felis ISSN 2398-2950

Ultrasonography: kidney

Contributor(s): Paul Mahoney

Introduction

  • The procedure is best performed in a quiet room with reduced lighting.
  • The patient should be still for the examination, often sedation is required.
  • A nurse is required to assist in restraint of the patient.
  • Optimal probe to skin contact is required.
  • The patient identification, date, and name of practice should be entered into the ultrasound machine before commencing the procedure.
  • Images of the examination should be kept for future reference, either as thermal prints, on video tape, on multiformat camera, or saved on hard disc.

Uses

  • Assessment of:
    • Palpable or radiographic unilateral or bilateral renomegaly   Kidney: renomegaly - compared with normal  .
    • Palpable or radiographic renal mass.
    • Palpable or radiographic mid or dorsal abdominal mass.
    • Reduced renal size.
    • Urinary incontinence   Urinary incontinence  .
    • Hematuria   Hematuria  .
    • Polydipsia.
    • Azotemia   Uremia  .

Advantages

  • Non-invasive.
  • Straightforward.
  • Non-painful.
  • Available in many practices.
  • Allows guided biopsies.
  • Short time required for assessment: 5-10 minutes, dependent upon patient compliance, and skill of ultrasonographer.

Experience will significantly reduce time required.

Disadvantages

  • Requires clipping of patient's coat.
  • Normal ultrasonographic appearance does not exclude disease.
  • Abnormal ultrasonographic appearance does not always represent significant disease.
  • Similar ultrasonographic appearance with different diseases.

Problems

  • Inadequate probe-skin contact.
  • Inadequate clipping of coat.
  • Inadequate use of ultrasound gel.
  • Inadequate restraint of an active cat.
  • Equipment failure.

Alternatives

  • Radiography: provides information about size and shape of organ   Radiography: abdomen  . Contrast studies   Radiography: intravenous urography  provide some information about internal architecture.
  • Cytopathology: fine needle aspirates   Fine-needle aspirate  can be obtained from enlarged kidneys for cytological examination. However, the information to be gained from this technique can be quite limited. The diagnostic value of this technique is improved by combining it with ultrasonography to guide the needle to the site of interest (particularly with focal lesions).
  • Histopathology: percutaneous, or biopsy taken at laparotomy   Kidney: surgical approach  . The diagnostic value of the former is also enhanced by combining it with ultrasonography.
  • MRI/CT: provide detailed information about architecture of organ but use limited by reduced availability of equipment except through referral centers.
  • Angiography: intravenous urography/pyelography may   Radiography: intravenous urography  provide some information about the internal architecture.

Criteria

  • Is the ultrasound examination appropriate?
  • Will the examination tell you what you need to know?
  • Will the management of the patient be affected by the findings?
  • Do you possess appropriate skills required?
    • Knowledge of normal anatomy, including location, vascular supply and drainage, and lymphatic drainage.
    • Knowledge of the normal ultrasonographic appearance.
    • Knowledge of the parenchymal variations seen with non-neoplastic disease.

Equipment

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Procedure

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Normal anatomy

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Pathological changes

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Further Reading

Publications

Refereed papers
  • Shiroma J T et al(1999)Effect of reproductive state on feline renal size. Vet Radiol Ultrasound40(3), 2420245.

Other sources of information

  • Burk R L and Ackerman N (1996)The Abdomen.In: Small Animal Radiology and Ultrasonography - A Diagnostic Atlas and Text.W B Saunders Company, Philadelphia. pp230-222.
  • Burk R L and Ackerman N (1996)The Abdomen.In: Small Animal Radiology and Ultrasonography - A Diagnostic Atlas and Text.W B Saunders Company, Philadelphia. pp322-357.
  • Nyland T G, Mattoon J S and Wisner E R (1995)Ultrasonography of the Urinary Tract and Adrenal Glands.In: Veterinary Diagnostic Ultrasound.Eds Nyland T G & Mattoon J S. W B Saunders Company, Philadelphia. pp95-110.


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