Transitional cell carcinoma of the urinary bladder is estimated to affect between 20,000 and 30,000 dogs each year in the United States. This is the most common form of urinary tract cancer and accounts for approximately 2% of all cancers in dogs.1 Treatment of urinary bladder cancer may involve surgical excision, radiation therapy, chemotherapy, or a combination of methods.1 Methods currently used to evaluate the response of bladder tumors to treatment include DCC, conventional 2-D ultrasonography, CT, and potentially MRI1; however, each of these imaging modalities has disadvantages or limitations. Computed tomography is expensive, and DCC is time-consuming and can be inaccurate because of variability in positioning and distension of the bladder during imaging. Both of these methods require sedation or general anesthesia as well as urinary catheterization and bladder distension, which are associated with risk of urinary tract rupture in dogs with TCC.1 Cystoscopy is often used to inspect and map lesions of the urethra and bladder and obtain a biopsy sample; however, measurements of tumor size cannot be made and anesthesia is typically needed. Advantages of conventional 2-D ultrasonography include a shorter examination time than that required for DCC or CT and more readily available equipment, compared with CT. Sedation or anesthesia is rarely needed in 2-D ultrasonography, but to provide acceptable data, 2-D ultrasonography requires that the same operator perform every examination, that the patient be positioned in the same way for each evaluation, and that bladder distension be consistent during multiple examination procedures. Therefore, some variability exists in the measurement of tumors to determine the response to treatment even under controlled circumstances.2
Three-dimensional ultrasonography has been used in humans to stage urinary bladder tumors3–6 and measure bladder volume.7 We hypothesized that 3-D ultrasonography would provide an accurate, noninvasive, and clinically practical method for measuring tumor volume in dogs with TCC of the bladder. Therefore, the primary objective of the study reported here was to determine the accuracy of 3-D ultrasonography for quantification of tumor volume in the urinary bladder of dogs with TCC, compared with the reference method of contrast-enhanced CT. A secondary objective was to determine the accuracy of 2-D ultrasonography for this same purpose.
Coefficient of variation
Double contrast cystography
Transitional cell carcinoma
Foley Catheter, Medline Industries, Mundelein, Ill.
iU22, Philips Healthcare, Bothell, Wash.
V6-2 or VL13-5, Philips Healthcare, Bothell, Wash.
Lightspeed QXi, General Electric Medical Systems, Milwaukee, Wis.
Ultravist, 300 mg/mL, Bayer Healthcare Pharmaceuticals, Wayne, NJ.
QLAB Advanced Quantification Software, version 7.1, Philips Healthcare, Bothell, Wash.
Automated Workstation, version 4. 1_04, General Electric Medical Systems, Milwaukee, Wis.
PROC UNIVARIATE, SAS, version 9.2, SAS Institute Inc, Cary, NC.
PROC GLM, SAS, version 9.2, SAS Institute Inc, Cary, NC.
PROC CORR, SAS, version 9.2, SAS Institute Inc, Cary, NC.
PROC REG, SAS, version 9.2, SAS Institute Inc, Cary, NC.
PROC MIXED, SAS, version 9.2, SAS Institute Inc, Cary, NC.
Analyse-it, version 2.20, Analyse-it Software Ltd, Leeds, West Yorkshire, England.
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