CONTRAST‐ENHANCED ULTRASOUND OF THE NORMAL CANINE PROSTATE GLAND

Canine prostate gland abnormalities affect a large number of adult male dogs. In veterinary medicine, the commonly used methods to diagnose canine prostate gland disease are digital rectal examination and abdominal ultrasound. We evaluated the ability of ultrasound contrast agent to provide additional information about the vascularity of the canine prostate gland; such information could be useful in detecting early prostate gland disease and in staging disease known to be present. We characterized the ultrasonographic appearance of prostate gland vascularity in 10 healthy dogs before and after the injection of an ultrasound contrast agent (Levovist^?). Before injecting Levovist^?, the prostate gland blood flow was classified as poor in all dogs, whereas after contrast agent injection blood flow was classified as moderate or good, in 3 and 7 dogs respectively. Knowledge of the status of prostate gland vascularity could be useful for the characterization, diagnosis and therapeutic monitoring of canine prostate gland lesions.     

DOPPLER ULTRASOUND OF THE PROSTATE IN NORMAL DOGS AND IN DOGS WITH CHRONIC LYMPHOCYTIC-LYMPHOPLASMOCYTIC PROSTATITIS

The prostate gland of 11 normal dogs and five dogs with histological confirmed chronic lymphocytic or lymphoplasmocytic prostatitis were imaged with grey-scale and Doppler ultrasound. Three vessel types (prostatic artery, capsular artery and parenchymal artery) were identified with color Doppler and the resistive index and maximum and minimum velocities were measured with pulsed wave Doppler. No differences between normal dogs and dogs with prostatitis was identified in either grey-scale ultrasound or in any Doppler parameters measured. Regardless of histologic diagnosis, acepromazine (0.05 mg/kg IV) caused a significant decrease in capsular artery maximum and minimum velocities and prostatic artery resistive index. This study establishes normal Doppler ultrasound parameters for the intact male canine prostate gland. Additional studies are necessary to further evaluate the clinical utility of Doppler ultrasound in canine prostatic diseases.     

DETERMINATION OF CANINE PROSTATIC VOLUME USING TRANSABDOMINAL ULTRASONOGRAPHY

The prostate gland from cadavers of 12 intact adult male dogs euthanized less than 3 hour were used to compare prostatic volume measured by ultrasonography to volume measured by water displacement, and to determine specific gravity of the canine prostate. Prostate glands were scanned by transabdominal ultrasonography with a 4-7 MHz curved linear array transducer. The greatest craniocaudal (L), transverse (W), and dorsoventral (D) diameters of the prostate were recorded. Prostatic volume was calculated using formulas for an ellipsoid and for a box. Prostate glands were removed, and the prostate weight was measured and prostatic volume was measured by water displacement. The mean +/- SD specific gravity of the prostate was 1 +/- 0.05 (range = 0.90 to 1.09) g/cm. There were positive correlations (R2 = 0.94) between prostatic volume calculated from ultrasound measurement and measured volume. Measured prostatic volume (VM) can be predicted using the formula: VM = [1/2.6 (L x W x D)] + 1.8 (cm3).     

Chronic effect of transrectal split-focus ultrasonic ablation on canine prostatic tissue

The treatment time needed for high-intensity focused ultrasound (HIFU) ablation might be decreased substantially by using the split-focus approach, so we made a prototype 4.2-MHz split-focus therapeutic transducer combined with a small 6.5-MHz imaging ultrasonic probe for transrectally treatment of canine prostatic cancer and used it to experimentally evaluate the feasibility of using split-focus transrectal HIFU to ablate canine prostatic tissue without injuring surrounding tissues. The prostates of 5 dogs were transrectally treated with split-focus ablation at a peak intensity in the water of 1.7 kW/cm(2) for 4 s (4 shots) under the guidance of ultrasonic B-mode imaging. After ultrasonic exposure, the prostates became stiff because of thermal effect of HIFU. For the first 3-5 days after treatment, dogs were catheterized daily for urinary management and treated with oral antibiotics to prevent urinary tract infection. The dogs were able to urinate normally by a week after. Within two weeks a large centrally located cystic cavity had formed in the prostate by replacing the necrotic parenchyma around the prostatic urethra. Necropsy three months after treatment found the rectum and prostate capsule to be normal grossly and histologically. The 4 shots of split-focus HIFU destroyed the prostatic parenchyma and created a prostatic cavity 0.34-0.45 cm(3) in volume without injuring surrounding tissues. These results suggest that split-focus HIFU ablation could be used for noninvasive treatment of prostatic cancer in dogs.     

PREPUBIC AND TRANSRECTAL ULTRASONOGRAPHY OF THE CANINE PROSTATE: A COMPARATIVE STUDY

A comparative study was conducted in ten dogs with signs of prostatic disease in order to evaluate the usefulness of the prepubic and transrectal ultrasonography for the examination of the prostate gland and for prostate biopsy guidance. Both techniques were adequate to identify the prostate gland and prostatic urethra. Transrectal ultrasound found 5 occurrencies of parenchymal echogenicity changes whereas the prepubic technique found only 2. Lesions in the cranial prostatic margin (two dogs) were detected only by prepubic ultrasound. Lesions of the caudal prostatic margin (six dogs), prostatic urethra disruption (two dogs) and prostatic capsule abnormalities (five dogs) were only recognized by the transrectal approach. Prepubic ultrasonography was useful for biopsy guidance of cranial prostatic lesions and transrectal ultrasonography was a good means for biopsy guidance of caudal lesions.     

Computed tomography of the prostate gland in apparently healthy entire dogs

Objectives : To describe the computed tomography (CT) features of the prostate gland and determine prostate size using CT in entire male dogs. Methods : The prostate gland was evaluated in 35 dogs. Morphological features including homogeneity, delineation, shape and intraprostatic differentiation were assessed. Height, length, width, area, volume and attenuation values of the prostate gland were measured. Ratios of prostatic height (rH), length and width to the sixth lumbar vertebral body length were calculated. Relationships of prostatic dimensions with body weight and age were evaluated. Results : The prostate gland was homogeneous in 29 dogs on non‐contrast images and 18 of 24 dogs on postcontrast images. Transverse images revealed a semi‐oval prostate gland in 29 dogs and irregularly shaped prostate gland in 6 dogs. A prominent median septum was observed in postcontrast images. Significant positive correlations were found between body weight and age and all prostatic dimensions except between age and rH. The mean ±sd values for attenuation were 59·3 ±9·1 and 121·3 ±22·7 HU in non‐contrast and postcontrast image, respectively. Clinical Significance : CT can be useful for evaluating morphological features of the prostate gland. Prostatic length or width is a better measure than height for computed tomographic estimation of prostate size.     

Computed Tomography of the Prostate Gland in Healthy Intact Dogs and Dogs with Benign Prostatic Hyperplasia

To date, there is only scarce data on the evaluation of the prostate gland in dogs using computed tomography (CT). The aims of our study were to describe CT features of BPH in dogs and to determine the size of the prostate gland in healthy male dogs and dogs with benign prostatic hyperplasia (BPH) through CT. Additionally, we aimed to compare and establish the most useful parameters for CT measurements of the prostate in patients with BPH. The study population consisted of 20 healthy intact male dogs and 20 male intact dogs with confirmed BPH. Pre‐ and post‐contrast CT studies were evaluated. The most common CT features in dogs with recognized BPH were symmetrical prostatomegaly and heterogeneity of the prostatic parenchyma. The mean prostatic density (D) was 56HU (±4.39) in pre‐contrast CT images and 84HU (±8) in post‐contrast images in dogs with BPH. The mean prostatic length (L) was 43.87 mm (±11), the mean width (W) amounted to 48.95 mm (±8.76) and the mean height (H) reached 44.9 mm (±9.48) in clinically affected patients. The mean ratios were: rL ? 2,12 (±0.5); rW ? 2.39 (±0.53) and rH ? 2.16 (±0.39) in the BPH group. The prostate should be considered to be enlarged when rL exceeds 3.05; rW exceeds 3.38 and rH exceeds 2.94. Our findings indicated that CT is a useful tool in diagnosing prostate disorders, including BPH. The heterogeneity, density and ratios of prostatic length, width and height can be useful parameters in the diagnosis of BPH.     

CHARACTERIZATION OF LYMPHOMATOUS LYMPH NODES IN DOGS USING CONTRAST HARMONIC AND POWER DOPPLER ULTRASOUND

Doppler ultrasound has been used in humans to determine angioarchitecture of lymph nodes as the criterion for the determination of malignancy. We hypothesized that the vascular and perfusion patterns of a canine malignant lymph node could be characterized with intravenous microbubble ultrasound contrast media and that contrast harmonic ultrasound could provide better conspicuity of the angioarchitecture when compared with Power Doppler ultrasound. In this study, 11 peripheral lymph nodes in dogs with histologically verified malignant lymphoma were imaged with fundamental ultrasound, Power Doppler ultrasound, and three contrast harmonic pulse sequences to characterize the vascular pattern and perfusion. Vascular imaging was greatly enhanced in these nodes with 2.13 times more vessels seen with contrast harmonic ultrasound compared with Power Doppler ultrasound (P < 0.01). The angioarchitecture of lymphomatous lymph nodes of dogs in this study were similar to those previously described in malignant superficial lymph nodes in human patients; 45.5% of the nodes had displacement of the central hilar vessel, 45.5% had aberrant vessels, 63.6% had pericapsular vessels, 36.4% had subcapsular vessels, and 81.8% had loss of the central hyperechoic band in fundamental sonography. Poor perfusion, indicated by a lower mean pixel intensity increase between pre- and postcontrast administration images, was seen in 36.4% of the lymph nodes while 63.6% had fair to good perfusion. The perfusion patterns in nine of the 11 lymph nodes were homogenous and two showed focal hypoperfused regions. We conclude that Power Doppler and contrast harmonic ultrasound are beneficial in accurately depicting angioarchitechture and can provide additional information in determining the presence of malignant vascular characteristics within lymphomatous nodes in dogs.     

Use of contrast-enhanced ultrasound for characterization of focal splenic lesions.

Contrast-enhanced ultrasound was used to study focal and multifocal lesions of the spleen in 26 dogs and two cats affected by 11 benign and 18 malignant splenic diseases. A second-generation microbubble contrast medium (Sonovue) was injected into the cephalic vein and enhancement patterns were subjectively described and time intensity curves calculated. Final diagnosis was obtained by histopathologic examination after splenectomy (n=19) or by needle aspiration and sonographic follow-up after 4 and 8 weeks (n=9). Contrast-enhanced ultrasound parameters, improving the characterization between benign and malignant lesions, were established. The most useful criterion was the hypoechogenicity of the lesion in the wash-out phase combined with the presence of tortuous feeding vessels, which was observed in association with malignancy. All malignant lesions were hypoechoic to the surrounding spleen 30s after starting the contrast medium injection. Lymphosarcoma and hemangiosarcoma had characteristic perfusion patterns. Lymphosarcoma had rapid time to peak and early wash-out phase with a honeycomb pattern during the wash-out. Hemangiosarcomas were large nonperfused masses in all phases surrounded by hypervascular splenic parenchyma. Benign lesions except one hematoma and a benign histiocytoma had the same perfusion pattern as the surrounding spleen. Ultrasonographic and contrast-enhanced ultrasound findings of an accessory spleen are reported. Contrast-enhanced ultrasound can improve the characterization of focal or multifocal lesions of the spleen.     

CONTRAST‐ENHANCED ULTRASONOGRAPHIC CHARACTERISTICS OF ADRENAL GLANDS IN DOGS WITH PITUITARY‐DEPENDENT HYPERADRENOCORTICISM

A noninvasive method for quantifying adrenal gland vascular patterns could be helpful for improving detection of adrenal gland disease in dogs. The purpose of this retrospective study was to compare the contrast‐enhanced ultrasound (CEUS) characteristics of adrenal glands in 18 dogs with pituitary‐dependent hyperadrenocorticism (PDH) vs. four clinically healthy dogs. Each dog received a bolus of the contrast agent (SonoVue®, 0.03 ml/kg of body weight) into the cephalic vein, immediately followed by a 5 ml saline flush. Dynamic contrast enhancement was analyzed using time–intensity curves in two regions of interest drawn manually in the caudal part of the adrenal cortex and medulla, respectively. In healthy dogs, contrast enhancement distribution was homogeneous and exhibited increased intensity from the medulla to the cortex. In the washout phase, there was a gradual and homogeneous decrease of enhancement of the adrenal gland. For all dogs with PDH, there was rapid, chaotic, and simultaneous contrast enhancement in both the medulla and cortex. Three distinct perfusion patterns were observed. Peak perfusion intensity was approximately twice as high (P < 0.05) in dogs with PDH compared with that of healthy dogs (28.90 ± 10.36 vs. 48.47 ± 15.28, respectively). In dogs with PDH, adrenal blood flow and blood volume values were approximately two‐ to fourfold (P < 0.05) greater than those of controls. Findings from the present study support the use of CEUS as a clinical tool for characterizing canine adrenal gland disease based on changes in vascular patterns.     

Two-dimensional, gray-scale ultrasonography. Applications in canine prostatic disease

The technique of and general appearance of suprapubic gray-scale prostatic ultrasonography in the dog are described. Using case examples, the various spontaneous diseases of the canine prostate are described and compared to the defined normal appearance of the prostate. An integrated approach to imaging the canine prostate gland is advocated and includes radiographic techniques, specifically distension retrograde urethrocystography. A clinically relevant classification scheme for use with microbiologic, cytologic, and imaging techniques is proposed.     

HELICAL COMPUTED TOMOGRAPHIC ANGIOGRAPHY OF THE NORMAL CANINE PANCREAS

Helical abdominal computed tomography (CT) was performed in nine normal beagle-mix dogs. Following cephalic vein injection of ionic iodinated contrast medium via power injector (rate 5 ml/s) dual-phase CT was performed in all dogs. A delayed scan was performed in five dogs between 5 and 13 min after the contrast medium injection. The median time of appearance of contrast medium in the aorta and gastroduodenal artery was 6.3 and 7 s, post start injection and 12 and 12.2 s in the gastroduodenal and portal vein, resulting in a purely arterial pancreatic time window of 5-6s. Pancreatic veins and parenchyma remained enhanced until the end of the dynamic scan (40s). The pancreatic parenchyma showed heterogeneous arterial and homogenous venous contrast enhancement which was slightly hypoattenuating compared to the liver. Delayed scans provided best delineation of the pancreas from the liver. The common bile duct could be identified ventral and to the right of the portal vein joining the dorsomedial aspect of proximal duodenum. Because of the very short time window and variable onset of pure arterial enhancement careful planning of dual-phase studies with previous dynamic CT is recommended. Dual-phase CT angiography enables assessment of the arterial supply, parenchymal perfusion and venous drainage of the canine pancreas.     

Assessment of Vascular Perfusion Kinetics Using Contrast‐enhanced Ultrasound for the Diagnosis of Prostatic Disease in Dogs

Vascular perfusion was assessed in 10 dogs without prostatic abnormalities and 26 dogs with prostatic disease using contrast‐enhanced ultrasound. The time to reach peak contrast intensity (TTP) and peak perfusion intensity (PPI) were measured, and histological biopsies were collected from each dog. Biopsies confirmed normal prostate (n = 10), benign prostatic hyperplasia (n = 11), mixed benign pathology (n = 9), prostatitis (n = 1), prostatic malignancy [adenocarcinoma (n = 4); leiomyosarcoma (n = 1)]. In normal dogs, mean PPI was 16.8% ± 5.8 SD, and mean TTP was 33.6 ± 6.4 s. Benign conditions overall were not statistically different from normal dogs (p > 0.05); for benign prostatic hyperplasia, mean PPI was 16.9 ± 3.8%, and mean TTP was 26.2 ± 5.8 s; for mixed benign pathology mean PPI was 14.8 ± 7.8%, and mean TTP was 31.9 ± 9.7 s; for prostatitis, PPI was 14.2%, and TTP was 25.9 s. The malignant conditions overall had perfusion values that differed from the normal dogs (p < 0.05), although evaluation of the data for individual malignancies did not demonstrate a consistent trend; for adenocarcinomas, the PPI was numerically higher with a mean of 23.7 ± 1.9%, and the mean TTP was 26.9 ± 4.8 s, whilst for the dog with leiomyosarcoma values were numerically lower with a PPI of 14.1% and TTP of 41.3 s. Contrast‐enhanced ultrasound appears to offer some ability to document differences in perfusion that may differentiate between malignant and benign lesions, although studies with larger numbers of animals are required to confirm this contention.     

Advances in Prostatic Diagnostics in Dogs: The Role of Canine Prostatic Specific Esterase in the Early Diagnosis of Prostatic Disorders

In last years, following the increased canine life expectancy and the rising attention pet-owners devote to their animals, several authors have carried on investigations concerning new techniques to early identify canine prostatic disorders that might affect the dog's quality of life. Prostatic disorders often have an asymptomatic onset and their early diagnosis is difficult: hence, they are usually identified at an advanced stage, only. Traditionally, the diagnosis of prostatic disorders is based on noninvasive tools, such as transrectal and abdominal palpation, seminal or prostatic fluid evaluation, and urinalysis and imaging. On the other hand, a definite diagnosis of prostatic abnormalities could be achieved through prostatic parenchyma Fine Needle Aspiration (FNA) or biopsy. However, these investigations are performed rarely because of their invasiveness. Thus, several authors investigated canine serum biomarkers in order to achieve an earlier diagnostic timing and to apply therapeutic strategies for better outcomes. The Canine Prostatic Specific Esterase (CPSE) has been identified as a suitable biomarker to be included in a prostate health screening program, following the model of prostate-specific antigen (PSA) in human medicine. A higher CPSE in dogs suffering from several prostatic diseases, such as benign prostatic hyperplasia, bacterial prostatitis, or prostatic carcinoma, was reported in literature. Thanks to the potential usefulness in clinical practice, further studies should investigate the potential role of CPSE in monitoring the medical treatment success in the male reproductive system. Moreover, the spreading availability of serum biomarkers, easily carried out on blood samples in clinical practice, could assure a more accurate evaluation of the actual prevalence of prostatic disorders. The CPSE is actually recognized as a promising diagnostic tool for the detection of prostatic disorders in a "prostate health screening program," in order to properly select those patients requiring further more accurate and expensive diagnostic investigations.     

CONTRAST‐ENHANCED ULTRASONOGRAPHY OF THE NORMAL CANINE ADRENAL GLAND

Contrast‐enhanced ultrasonography is useful in differentiating adrenal gland adenomas from nonadenomatous lesions in human patients. The purposes of this study were to evaluate the feasibility and to describe contrast‐enhanced ultrasonography of the normal canine adrenal gland. Six healthy female Beagles were injected with an intravenous bolus of a lipid‐shelled contrast agent (SonoVue^®). The aorta enhanced immediately followed by the renal artery and then the adrenal gland. Adrenal gland enhancement was uniform, centrifugal, and rapid from the medulla to the cortex. When maximum enhancement was reached, a gradual homogeneous decrease in echogenicity of the adrenal gland began and simultaneously enhancement of the phrenicoabdominal vessels was observed. While enhancement kept decreasing in the adrenal parenchyma, the renal vein, caudal vena cava, and phrenicoabdominal vein were characterized by persistent enhancement until the end of the study. A second contrast enhancement was observed, corresponding to the refilling time. Objective measurements were performed storing the images for off‐line image analysis using Image J (ImageJ^©). The shape of the time–intensity curve reflecting adrenal perfusion was similar in all dogs. Ratios of the values of the cortex and the medulla to the values of the renal artery were characterized by significant differences from initial upslope to the peak allowing differentiation between the cortex and the medulla for both adrenal glands only in this time period. Contrast‐enhanced ultrasonography of the adrenal glands is feasible in dogs and the optimal time for adrenal imaging is between 5 and 90 s after injection.     

Canine prostatic disease--comparison of ultrasonographic appearance with morphologic and microbiologic findings: 30 cases (1981-1985)

A retrospective analysis was made of 30 cases of canine prostatic disease, with the objective of identifying (via a prepubic approach) the 2-dimensional, gray-scale ultrasonographic appearance most often associated with the various spontaneous prostatic diseases. Ultrasonography was of value in characterizing the parenchymal architecture as normal vs focally hyperechoic and diffusely hyperechoic (associated with chronic inflammation and neoplasia) or focally hypoechoic or anechoic (either accompanied by distant enhancement), which was associated with retention cyst or abscess. Further specificity based only on abnormal echotexture was not possible. Ultrasonography facilitated the differentiation of radiographically identifiable prostatomegaly attributable to abscess or neoplasia from apparent prostatomegaly attributable to paraprostatic cyst. An imaging protocol consisting of distention retrograde urethrocystography and prepubic ultrasonography was recommended, as a distended bladder aided ultrasonographic identification of the prostate gland. In addition, the combination of urethral morphologic features and urethroprostatic reflux appearance complemented the ultrasonographic appearance for differentiation of prostatic abscess from prostatic carcinoma. A classification scheme for spontaneous canine prostatic disease combining germane imaging morphologic features with microscopic and microbiologic findings was proposed.     

EFFECT OF SEDATION ON CONTRAST‐ENHANCED ULTRASONOGRAPHY OF THE SPLEEN IN HEALTHY DOGS

Contrast‐enhanced ultrasound of the spleen enables the dynamic assessment of the perfusion of this organ, however, both subjective and quantitative evaluation can be strongly influenced by sedative agent administration. The purpose of this prospective, experimental study was to test effects of two sedative agents on splenic perfusion during contrast‐enhanced ultrasound of the spleen in a sample of healthy dogs. Contrast‐enhanced ultrasound of the spleen was repeated in six healthy Beagles following a cross‐over study design comparing three protocols: awake, butorphanol 0.2 mg/Kg intramuscular (IM), and dexmedetomidine 500 μg/m² IM. After intravenous injection of a phospholipid stabilized sulfur hexafluoride microbubble solution (SonoVue®, Bracco Imaging, Milano, Italy), the enhancement intensity and perfusion pattern of the splenic parenchyma were assessed and perfusion parameters were calculated. Normal spleen was slightly heterogeneous in the early phase, but the parenchyma was homogeneous at a later phase. Sedation with butorphanol did not modify perfusion of the spleen. Dexmedetomidine significantly reduced splenic enhancement, providing diffuse parenchymal hypoechogenicity during the entire examination. Measured parameters were significantly modified, with increased arrival time (AT; (< 0.0001) and time to peak (TTP; P < 0.0001), and decreased peak intensity (PI; P = 0.0108), wash‐in (P = 0.0014), and area under the curve (AUC; P = 0.0421). Findings supported the use of butorphanol and contraindicated the use of dexmedetomidine as sedatives for splenic contrast ultrasound procedures in dogs. Short‐term and diffuse heterogeneity of the spleen in the early venous phase was determined to be a normal finding.     

Intraoperative radiotherapy of carcinoma of the prostate gland in ten dogs

Ten dogs with carcinoma of the prostate gland were treated with intraoperative orthovoltage radiotherapy (radiation therapy to surgically exposed tumors). Seven dogs had tumor growth confined to the prostate gland and urethra, and 3 dogs had carcinoma of the prostate gland and regional lymph node involvement. Total radiation doses delivered to the prostate gland of 9 dogs and the affected regional lymph nodes of 3 dogs, using orthovoltage x-rays, ranged from 20 to 30 Gy. Carcinoma of the prostate gland of one dog was intraoperatively irradiated to 15 Gy and was then given a boost of 40 Gy, using cobalt-60 teletherapy. Survival time ranged from 41 to 750 days after intraoperative radiotherapy. Median and mean survival times for all dogs were 114 and 196 days, respectively. The median survival time for 7 dogs with localized prostatic carcinoma was 180 days, which was longer, but not significantly longer (P = 0.09), than the median survival time of 80 days in 3 dogs having prostatic carcinoma and metastatic disease. Intraoperative radiotherapy was tolerated well and caused complete response in 5 dogs. However, surgical complications in 2 dogs, which had subtotal lymphadenectomy or prostatic biopsy performed concurrently at the time of irradiation, resulted ultimately in their deaths. The 2 other dogs with metastatic disease and 1 dog without metastatic disease also had poor response to treatment. Our results indicated that intraoperative radiotherapy is an effective treatment for localized prostatic carcinoma in the dog.