Ultrasound is a common imaging technique used for examination of the dog's prostate gland that has proven to be successful for diagnosis of many clinical conditions. Whilst B-mode ultrasound is useful for assessment of the prostate gland, there appears to be substantial variation in the appearance of some pathological conditions, although individual experienced ultrasonographers often have a high aptitude for making a correct diagnosis. Here, we report the normal volume and appearance of the canine prostate gland with B-mode ultrasound and use thematic analysis to identify the categories described by experienced ultrasonographers when reporting both normal and abnormal findings. Four thematic categories were identified: background echotexture, parenchymal stippling, generalized appearance and focal changes. We found that a relatively narrow variety of thematic variables (descriptors) were used for reporting of prostatic pathology within these thematic categories. There was also poor association between these descriptors and the underlying pathology, with the only unique descriptors being ‘cysts’ for benign prostatic hyperplasia and ‘parenchymal mineralization’ for adenocarcinoma. In comparison with the limitations of B-mode ultrasound, we document the value of measurement of vascular perfusion kinetics using contrast-enhanced ultrasound and demonstrate how perfusion kinetics differ between benign and malignant prostatic disease.