Prostatic Perfusion in the Dog Using Contrast-Enhanced Doppler Ultrasound M Russo 1 , M Vignoli 2 , G Catone 3 , F Rossi 2 , G Attanasi 2 and GCW England 4 1 Obstetric Unit, Department of Veterinary Clinical Sciences, Veterinary School, University of Naples, Napoli, Italy; 2 Private Practice Veterinary Clinic dell’Orologio, Sasso Marconi- Bologna-Italy; 3 Department of Veterinary Clinical Sciences, Veterinary School, University of Camerino (MC)Italy; 4 The University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire, UK Contents Ultrasonography has become the imaging modality of choice for evaluation of the prostate gland in the dog. Unfortunately, despite providing excellent images, it may be difficult to differentiate the common canine prostatic diseases with ultrasound because many have a similar ultrasonographic appearance. Real-time contrast-enhanced ultrasound was used to monitor and characterise the normal perfusion pattern and perfusion dynamics of the canine prostate gland when using a micro bubble contrast agent. In all contrast studies, the prostatic artery, entered the prostate gland on the dorso-lateral surface then tunnelled into the prostatic capsule and branched into many small parenchymal arteries which were directed medially towards the urethra to supply the body of the prostate gland. The flow of the contrast medium into the prostatic parenchyma was visible after 15 s. During the wash- in phase, there was an homogenous enhancement of the prostatic parenchyma. During the wash-out phase, an homo- genous decrease of the echogenicity was visible in all cases. Introduction In the last 15 years, ultrasonography has become the imaging modality of choice for evaluation of the prostate gland in the dog. This technique allows precise prostatic measurement in addition to the evaluation of the appearance of prostatic parenchyma. The latter has been well described (Cartee and Rowles 1983; Feeney et al. 1987; Cooney et al. 1992). Unfortunately, despite providing excellent images, it may be difficult to differentiate the common canine prostatic diseases with ultrasound because many have a similar ultrasono- graphic appearance (Mahaffey et al. 1995). In humans, colour-flow Doppler evaluation has been used with some success for the detection of prostatic neoplasia because this is often associated with increased number and irregularity of colour signals and an overall disorganized vascular appearance. However, acute inflammatory prostatic disease also has a similar ultrasonographic appearance again making these conditions difficult to differentiate (Kelly et al. 1993). As a result, prostatic biopsy is usually indicated to obtain a definitive diagnosis. Recently, micro bubble-based ultrasound contrast media have been developed. These have been shown to enhance the ability of ultrasound to detect vasculariza- tion and measure perfusion of organs such that the technique could be useful for imaging tumours. The purpose of the present study was to describe for the canine prostate gland the normal perfusion pattern and perfusion dynamics when using a micro bubble tech- nique. The aim was to generate normal data on perfusion kinetics to provide a basis for comparison for later studies in clinical patients with diffuse or focal prostatic disease. Materials and Methods Five clinically normal adult intact male dogs (four mixed breed and a German Shepherd dog) with a mean age of approximately 2.4 years, weighing between 6.5 and 37 kg were used in this study. Ethical approval for the study was gained through the University’s normal procedure. Prior to the ultrasonographic evaluation, a complete physical examination including rectal palpa- tion of the prostate gland, abdominal radiographs, serum chemistry profile, complete blood cell count and urinalysis were performed. A 20-G intravenous cannula was placed in the cephalic vein. All patients underwent general anaesthesia with diazepam 0.2 mg ⁄ kg i.v. and propofol 4 mg ⁄ kg i.v., which was given until tracheal intubation was possible. Anaesthesia was maintained with isoflurane (1–3% in oxygen) and saline was administered during the procedure. All dogs were maintained in right lateral recumbency and haemoglo- bin oxygen saturation, heart rate, blood pressure and CO 2 -saturation were monitored continuously through- out anaesthesia. Ultrasound examinations of the caudal abdomen were undertaken with a 5–7.5 MHz linear with coded harmonic capability (Mylab 30, Esaote-CnTI System, Esaote, Genova, Italy). Longitudinal and transverse prostatic diameters were measured and the colour Doppler examination was performed at a frame rate of 0.7–1.4 frames per second. A second-generation contrast agent SonoVue Ò (Sulphur hexafluoride microbubbles; Bracco Imaging S.p.A., Milan, Italy) and a dedicated contrast-enhanced ultrasound analytical software (Contrast Tuned Imaging – CnTI TM -Contrast Tuned Imaging technology, Esaote, Genova, Italy) were used. Once the prostate was visualized, the power Doppler was applied in order to follow the prostatic branches of the urogenital artery that enter the prostate gland at the dorso-lateral surfaces. Power Doppler examination was undertaken before and after the contrast study. To reduce the acoustic impact of the ultrasound waves on the micro bubble contrast agent, and to increase the persistence of the contrast medium in the blood, the mechanical index was always lower than 0.1 (range 0.05–0.1),which corresponds to an acoustic pressure lower than 45 kPa. A single focal zone was placed in the deepest part of the prostate. The overall gain and time-gain compensation were set so that no signal from the prostatic parenchyma was present and Reprod Dom Anim 44 (Suppl. 2), 334–335 (2009); doi: 10.1111/j.1439-0531.2009.01442.x ISSN 0936-6768 Ó 2009 The Authors. Journal compilation Ó 2009 Blackwell Verlag GmbH