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Special Procedures



 


 

CystourethrogramGo to Top

Description :

Cystourethrography is a contrast study for the evaluation of the urinary bladder and urethra. With rare exception (e.g. the patient cannot have a urethral catheter passed), all of the phases will be performed :

  • Pneumocystogram (negative contrast used).
  • Double-Contrast Cystogram (both negative and positive contrast used).
  • Cystogram (positive contrast used).
  • Retrograde Urethrogram (contrast agent injected via catheter while exposing radiographs).
  • Antegrade Urethrogram (radiolucent object used to compress urinary bladder to get patient to expel urine in a voiding manner).

Indications for this procedure :

  • Evaluate for bladder and urethral masses, and other mural lesions such as urachal diverticuli that may be directly causative of lower urinary tract signs or contributing to recurrent infection.
  • Assessment of location of a known mass to better estimate its relationship to the trigone and assess surgical resectability.
  • Evaluate for bladder and urethral calculi.
  • Evaluate some functional information in incontinent patients.
  • Evaluate for anatomic abnormalities such as a pelvic bladder and urethro-rectal fistulae.
  • Evaluate for bladder or urethral tears.

Contraindications and complications for this procedure :

  • The bladder or urethra are at some risk for tear or rupture - this is generally only an issue if the tissue is already compromised by disease or previous surgery.
  • Air embolism is a RARE and potentially fatal complication seen with pneumocystography and double-contrast cystography. It is more common in patients with gross hematuria. We use CO2 as our contrast gas to greatly decrease the already small risk.
  • As with any procedure involving urinary catheterization, infection may occur.
  • Urine culture should not be considered valid for 2 days after the study because of the anti-microbial effects of iodine contrast.


 

Dynamic EsophagogramGo to Top

Description :

Radiographic study is done using positive contrast media (barium or non-ionic iodine) of different types and textures to evaluate esophageal location and morphology. Fluoroscopy is the optimum technique for the assessment of esophageal motility and function, particularly in oropharyngeal disorders.

Indications for this procedure :

  • Assessing an animal with suspected esophageal or pharyngeal disease based on clinical signs of regurgitation, gagging or dysphagia.
  • Evaluating an animal with a foreign body, stricture (including vascular ring anomalies) or trauma to the esophagus.
  • Evaluating the esophagus for abnormal position in an animal with a cervical or mediastinal mass.
  • Assessment of esophageal motility.

Contraindications and complications for this procedure :

  • Benefits of the procedure need to be weighed against risk of aspiration - however, the contrast media themselves (including barium) are not toxic or otherwise harmful to the airways. Complications result from aspirating a large volume of material (rare in this setting) and/or contamination of the aspired material with bacteria from the GI tract.
  • Easily defined, moderate to severe, uniform gas dilation of the esophagus on survey radiographs without clinical evidence of oropharyngeal dysphagia is a RELATIVE contraindication to the procedure. Esophagography generally does not contribute any further information in such cases. Cases that are suspected of having oropharyngeal disease AND generalized megesophagus should be assessed, however.
  • Barium leakage through a tear in the esophagus or pharynx can result in a granulomatous cellulitis/mediastinitis. Non-ionic iodine is used as an initial medium in cases where a tear is suspected, but may not show all tears, so negative iodine studies are followed by barium studies.
  • Ideally, an upper GI (UGI) series should not immediately follow an esophagogram as barium-coated food is given as part of this study, which can interfere with interpretation of an UGI. If it is known that both procedures will be done, the esophagogram should follow the UGI wherever possible.


 

Airway FluoroscopyGo to Top

Description :

Fluoroscopy uses an x-ray tube and a fluoroscopic screen with an image intensifier to create a real-time image of moving objects, in this instance the trachea, bronchi, diaphragm, lungs, and structures in the larynx and pharynx.

Indications for this procedure :

  • Assessing an animal with suspected laryngeal, pharyngeal, tracheal or bronchial collapse.
  • Assessing an animal with suspected diaphragmatic paralysis/hemiparalysis.
  • Evaluation of lung "nodules" to try to confirm that they are in the lung and not artifacts of superimposition or lesions outside the lungs. At this time we are not offering fluoroscopically guided sampling.

Contraindications and complications for this procedure :

  • Essentially none outside of the risk of a negative study, or a study that is incomplete because of inability to induce a clinically reported cough or because the study had to be aborted because of patient distress.


 

Intravenous Urography (IVU, IVP)Go to Top

Description :

Intravenous Urography (Pyelography) is a progressive radiographic study done after the intravenous injection of an iodine contrast agent which allows visualization of the kidneys, ureters, and limited information on the urinary bladder. The procedure uses multiple radiographs at a particular sequence thus showing contrast enhancement of the renal vasculature (vascular phase, sometimes not acquired), renal parenchyma (nephrogram phase), renal collecting system, and ureters (pyelogram phase) as contrast medium is excreted by the kidneys and passes through the renal collecting system, ureters, and into the urinary bladder.

Indications for this procedure :

  • Evaluate the size, shape, and position of the kidneys, ureters and bladder.
  • Investigate the cause and source of hematuria and pyuria when the bladder is not believed to be the source.
  • Suspected calculi or masses involving the kidneys or ureters.
  • Urinary incontinence, particularly if ectopic ureters are suspected.
  • Determine the effect of retroperitoneal or intraabdominal masses on the structure, position and function of the urinary tract.
  • Evaluate the result of trauma to the urinary tract, particularly to assess for tears in the ureters.
  • Qualitative assessment of renal function and patency of the urinary tract.
  • Postoperative assessment of the urinary tract.

Contraindications and complications for this procedure :

  • Anuria (absence of urine production).
  • Severe dehydration.
  • Uremia is not a contraindication as long as the patient is hydrated and producing urine. However, the diagnostic quality of the study may be compromised because of poor contrast concentration.
  • Known allergy to iodine is an absolute contraindication.
  • Vomiting is a common side effect that is generally self-limiting.
  • Allergic reactions include urticaria, hypotension and bronchospasm.
  • Contrast medium-induced renal failure is a rare, idiosyncratic reaction.


 

Upper Gastrointestinal (GI) SeriesGo to Top

Description :

Barium (in some cases, iodine-based) contrast is administered into the stomach via orogastric or nasogastric intubation. The patient is generally initially imaged with fluoroscopy to evaluate gastric motility and pyloric function, and then a series of static images are taken. The exact timing and duration of the study will vary with the initial findings.

Indications for this procedure :

  • Assessment of the size, shape, and position of the stomach and small intestine.
  • Evaluation for suspected foreign body or other causes of mechanical ileus.
  • Investigation of gastric outflow abnormalities including gastric foreign bodies acting as a "ball valve", pyloric hypertrophy and neoplasia.
  • Investigation of gastrointestinal motility.
  • Evaluation of the mucosa and wall of the stomach and small intestine.

Contraindications, considerations and complications for this procedure :

  • Opioid medications such as commonly used for pain management and restraint can have marked effects on GI motility and should be avoided.
  • The patient should be fasted for 18-24 hours prior to the procedure as the presence of food in the stomach can obscure lucent foreign material and other lesions, and complicates the interpretation of gastric emptying time.
  • The patient must have an enema to clear the colon of fecal material (with the exception of emergent cases) which can obscure evaluation of the small intestine as well as delay gastric emptying and small intestinal transit time. The enema will be performed at the VMC on the morning of the procedure.
  • Aspiration is a very rare complication as we administer contrast by gavage and verify tube location under fluoroscopy. However, if the patient vomits, aspiration may occur. Barium contrast is not toxic to the airway, although bacterial contamination with GI or oral flora may result in pneumonia. Ionic iodine contrast can cause fatal pulmonary edema and is avoided in patients considered at significant risk for emesis. Non-ionic iodine contrast agents are used in patients who are at risk for both emesis and are suspected of having a perforation.
  • If a GI perforation is suspected, iodine contrast will be used. If there is a perforation present that was not suspected, however, barium leakage into the peritoneum could occur.


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