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  • Author or Editor: Jiwon Kang x
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Abstract

OBJECTIVE

To evaluate effects of airway pressure on contrast enhancement and diameter of the pulmonary artery and determine the optimal airway pressure for pulmonary CT angiography in dogs.

ANIMALS

8 healthy Beagles.

PROCEDURES

Thoracic CT was performed at end-expiration (0 cm H2O) and 2 positive-pressure end-inspirations (10 and 20 cm H2O). Attenuation curves of enhancement for the sinus of the pulmonary trunk artery were obtained by use of a bolus technique. Contrast medium (300 mg of I/kg) was administered IV, and CT imaging began at the time of peak enhancement. At each pressure, time to peak enhancement, ratio of blood flow from the caudal vena cava to the right side of the heart (KCdVC), and enhancement characteristics and diameter changes of the pulmonary artery were evaluated.

RESULTS

All dogs had a significant delay for time to peak enhancement in the sinus of the pulmonary trunk artery as airway pressure increased. The KCdVC progressively increased as airway pressure increased, and there was low contrast enhancement and increased pulmonary artery filling defects at 20 cm H2O. All pulmonary arteries had marked increases in diameter as pressure increased. Arterial distensibility in the gravity-dependent cranial lung region was greater than that in the gravity-independent caudal lung region at the 2 positive-pressure end-inspirations.

CONCLUSIONS AND CLINICAL RELEVANCE

Airway pressure affected time to peak enhancement, KCdVC, contrast enhancement, and pulmonary artery diameter. Results suggested that 10 cm H2O could be an optimal pressure for evaluation of the pulmonary artery of dogs by use of CT angiography. (Am J Vet Res 2019;80;756–763)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To assess effects of catheter diameter and injection rate of flush solution (saline [0.9% NaCl] solution) on renal contrast-enhanced ultrasonography (CEUS) with perfluorobutane in dogs.

ANIMALS

5 healthy Beagles.

PROCEDURES

CEUS of the kidneys was performed by IV injection of contrast medium (0.0125 mL/kg) followed by injection of 5 mL of saline solution at rates of 1, 3, and 5 mL/s through a 20-gauge or 24-gauge catheter; thus, CEUS was repeated 3 times for each catheter diameter. Time-intensity curves were created for regions of interest drawn in the renal cortex and medulla. Repeatability was determined by calculating the coefficient of variation (CV). Statistical analysis was used to assess whether perfusion variables or CV of the perfusion variables was associated with catheter diameter or injection rate.

RESULTS

Perfusion variables did not differ significantly between catheter diameters. Time to peak enhancement (TTP) in the renal cortex was affected by injection rate, and there were significantly lower values for TTP at higher injection rates. The CEUS variables with the lowest CVs among injection rates were TTP for the renal cortex; the CV for TTP of the renal cortex was the lowest at an injection rate of 5 mL/s.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of a 24-gauge catheter did not alter CEUS with perfluorobutane; therefore, such catheters could be used for CEUS of the kidneys of small dogs. Moreover, a rate of 5 mL/s is recommended for injection of flush solution to obtain greater accuracy for renal CEUS in Beagles.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate a contrast medium that could be used for radiographic and ultrasonographic assessment of the small intestine in dogs.

ANIMALS

8 healthy adult Beagles.

PROCEDURES

Carboxymethylcellulose (CMC; 0.5% solution) was combined with iohexol (300 mg of iodine/mL) to yield modified contrast medium (MCM). Dogs were orally administered the first of 3 MCMs (10 mL/kg [9.5 mL of CMC/kg plus 0.5 mL of iohexol/kg]). Radiographic and ultrasonographic assessment of the small intestine followed 10 minutes after administration and every 10 minutes thereafter, until MCM was seen within the ascending colon. Minimally, 1 week elapsed between dosing of subsequent MCMs (10 mL/kg [9 mL of CMC/kg plus 1 mL of iohexol/kg and 8.5 mL of CMC/kg plus 1.5 mL of iohexol/kg]) and repeated radiography and ultrasonography.

RESULTS

Radiographic contrast enhancement of the small intestine was best with MCM that combined 8.5 mL of CMC/kg and 1.5 mL of iohexol/kg. Mean small intestinal transit time for all MCMs was 86 minutes. All MCMs did not interfere with ultrasonographic assessment of the small intestine and may have improved visualization of the far-field small intestinal walls.

CONCLUSIONS AND CLINICAL RELEVANCE

An MCM that combined 8.5 mL of 0.5% CMC/kg and 1.5 mL of iohexol/kg could be an alternative to barium or iohexol alone for contrast small intestinal radiography in dogs, especially when abdominal ultrasonography is to follow contrast radiography.

Full access
in American Journal of Veterinary Research