Canis ISSN: 2398-2942

Ultrasonography: kidney

Contributor(s): Paul Mahoney

Introduction

  • The procedure is best performed in a quiet room with reduced lighting Abdominal ultrasound video 06: kidney examination.
  • The patient should be still for the examination, occasionally 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 disk.

Uses

  • Assessment of:
    • Palpable or radiographic unilateral or bilateral renomegaly.
    • Palpable or radiographic renal mass Kidney mass - radiograph.
    • Palpable or radiographic mid or dorsal abdominal mass Adrenal mass - radiograph.
    • Reduced renal size Kidney small - radiograph.
    • 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: 5-15 min, 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 dog.
  • Equipment failure.

Alternatives

  • Radiography: but only provides information about size and shape of organ and not internal architecture. Contrast studies provide some information about internal architecture.
  • Cytopathology: fine needle aspirates 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. The information gained by this technique is usually of greater value than fine needle aspirate.
  • 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 provides some information about 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

  • Recent references from VetMed Resource and PubMed.
  • Barr F J (1990) Evaluation of Ultrasound as a method of assessing renal size in dogs. JSAP 31, 174-179.
  • Barr F J, Holt P E & Gibbs C (1990) Ultrasonographic measurement of normal renal parameters. JSAP 31, 180-184.

Other sources of information

  • Burk R L & Ackerman N (1996) The Abdomen. In: Small Animal Radiology and Ultrasonography - A Diagnostic Atlas and Text. Eds: Burk R L & Ackerman N. W B Saunders Company, Philadelphia. pp 230-232.
  • Burk R L & Ackerman N (1996) The Abdomen. In: Small Animal Radiology and Ultrasonography - A Diagnostic Atlas and Text. Eds: Burk R L & Ackerman N. W B Saunders Company, Philadelphia. pp 322-357.
  • Nyland T G, Mattoon J S & Wisner E R (1995) Ultrasonography of the Urinary Tract and Adrenal Glands. In: Veterinary Diagnostic Ultrasound. Eds: Nyland T G and Mattoon J S. W B Saunders Company, Philadelphia. pp 95-110.


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