EFFECT OF CONTRAST MEDIUM DOSE AND IMAGE ACQUISITION TIMING ON URETERAL OPACIFICATION IN THE NORMAL DOG AS ASSESSED BY COMPUTED TOMOGRAPHY

Computed tomography (CT) excretory urography was performed in five adult female dogs after intravenous injection of a bolus of four different doses of water-soluble iodinated contrast medium (100, 200, 400, and 800 mg1/kg). CT images centered over the urinary bladder were performed before injection and 1,3,5,7,9,11,15,20,25,30,40,50, and 60 minutes after injection. Opacification of both ureters was evaluated by measuring maximum CT number of individual ureters at each time. Time opacification curves were generated for each dose. Best opacification of the ureters was obtained with 400 and 800 mgl/kg, with a constant peak at 3 minutes and durable opacification for 1 hour. Insufficient opacification was obtained with lower dose of 100 and 200 mgI/kg.     

URETERAL DIVERTICULA IN TWO DOGS

We describe ureteral diverticula in two dogs and briefly review the related literature. The diagnosis of this condition is radiographic and based on the excretory urographic observation of multiple ureteral outpouchings. Pathologically, ureteral transitional cell hyperplasia and mucinous metaplasia result in submucosal proliferation of the urothelium and the formation of crypts and small cysts. Ureteral diverticulosis in humans is associated with an increased risk of urothelial malignancies, such as transitional cell carcinoma of the urinary bladder. Clinically, both dogs were older, small breed neutered females. Both had a history of chronic urinary obstruction. One dog died during surgery to remove an adrenal mass, and the other was euthanized at the owner's request because of an inoperable bladder neoplasm. Histopathologic diagnosis of ureteral lesions confirmed the radiographic diagnosis of ureteral diverticula in both dogs.     

Advances in diagnostic imaging of the larynx and pharynx

Imaging of the larynx and pharynx has traditionally been limited to upper airway endoscopy and radiography. Recently, ultrasonography, magnetic resonance imaging and computed tomography have become used more widely. These modalities have increased our diagnostic yield when investigating disorders of the upper airway. The Case Report in this issue ( Koenig et al. 2012 ) describes the diagnosis and biopsy of a laryngeal mass using ultrasonography illustrating one novel application of laryngeal ultrasonography. Increased use of laryngeal ultrasonography and advanced imaging of the larynx and pharynx will hopefully lead to a better understanding of conditions of the upper airway and improved treatment strategies.     

IMAGING DIAGNOSIS—SUBLUMBAR PSEUDOMYCETOMA IN A PERSIAN CAT

A 6-year-old Persian cat was examined for constipation, anorexia, and vomiting that was subsequently found to be due to a pseudomycetoma originating from the descending colon and sublumbar region, and causing mechanical obstruction of the colon and rectum. Multiple discrete hyperechoic foci likely representing fungal grains within the lesion gave the mass a coarse echotexture on ultrasound and was supportive of the diagnosis and computed tomography allowed delineation the extent of the mass. A pseudomycetoma is a granulomatous/pyogranulomatous reaction that surrounds dermatophytic fungal hyphae. Definitive diagnosis of a dermatophytic pseudomycetoma requires identification of the etiologic agent by cultivation or immunohistochemical staining. A pseudomycetoma should be included in the differential diagnosis for an abdominal mass in a Persian cat, especially is accompanied by the sonographic findings noted above.