Determination of canine prostatic size in situ: comparison of direct caliper measurement with radiologic and transrectal ultrasonographic measurements.

The use of transrectal ultrasonography to estimate canine prostatic size in situ was evaluated and compared to that of direct measurement via calipers and an in situ radiologic procedure. The length, width, and depth of prostates were measured by transrectal ultrasound in both the transverse and sagittal planes from which prostatic volume was calculated. Prostatic volumes were subsequently transformed into prostatic weights using the following nomogram: prostatic Weight (g) = 0.602 x prostatic Volume (cm3) + 1.16. Prostatic weights estimated by ultrasound as well as by direct measurement with caliper were similar (P greater than 0.10) to the true gravimetric weight; however, prostate weights estimated by the radiological X-ray procedure were significantly (P less than 0.01) lower. The relationship between true gravimetric prostate weight and that estimated by ultrasound was described by the following regression equation: estimated weight (g) = 1.127 gravimetric weight (g) - 1.665; r = 0.900; P less than 0.001; n = 23. In summary, the results of this study demonstrate that transrectal ultrasonography can be used to accurately predict canine prostatic weight.