ABSTRACT The physiological effects of aging on renal hemodynamics in dogs are not yet well defined. This prospective analytical study aimed to evaluate renal aging using Doppler ultrasonography by comparing renal hemodynamic parameters between healthy young adult and healthy geriatric small‐breed dogs. Fifty‐eight healthy small‐breed dogs (≤10 kg) were divided into two groups (young adult and geriatric) and underwent renal Doppler ultrasonography to compare renal hemodynamic parameters between groups. A total of 116 kidneys were evaluated. Age‐related hemodynamic changes were identified. Geriatric dogs exhibited lower aortic peak systolic velocity (PSV) and main renal artery end‐diastolic velocity, as well as higher intrarenal resistive and pulsatility indices, compared with young adults. In addition, a trend towards lower PSV and higher resistive index in the main renal arteries, along with a higher renal‐to‐aortic ratio, was observed in geriatric dogs. These findings may provide valuable complementary information during routine ultrasonographic evaluation, contributing to the early detection of renal vascular alterations, monitoring of disease progression, and assessment of therapeutic response in renal disorders. Furthermore, they may support future research into renal vascular physiology and pathology.
Intra-abdominal cryptorchidism and testicular neoplasia are risk factors for the development of intra-abdominal testicular torsion (IATT). Testicular torsion may be associated with complete or incomplete vascular occlusion, leading to ischemia and necrosis, and, therefore, IATT necessitates urgent orchidectomy. This case series describes the CT features of complete (5/6) and incomplete (1/6) IATT in six dogs with surgically and histopathologically confirmed diagnoses, including torsion of both neoplastic (4/6) and non-neoplastic (2/6) testes. Clinical signs included acute abdominal pain, a palpable abdominal mass, inappetence, and vomiting. Testicular neoplasia included Seminoma (2/4) and Sertoli cell tumor (2/4). Both cases of Sertoli cell tumor were associated with hyperestrogenism, one of which had metastasized to the ipsilateral medial iliac lymph node (1/2). Orchidectomy was curative in 5/6 dogs. CT features of IATT included a mid or caudal intra-abdominal, soft tissue attenuating mass with a "whirl sign" of the testicular vascular pedicle, pampiniform plexus, and/or gubernaculum (6/6); enlargement of the testis, pampiniform plexus and epididymis (6/6); and peritoneal effusion (6/6). Features observed only in complete IATT were interruption of testicular arterial contrast filling (4/5), absent testicular parenchymal contrast enhancement, and absent contrast filling of the pampiniform plexus (5/5). By comparison, contrast enhancement or filling of these structures was present only in the incomplete IATT case. IATT should be considered a differential diagnosis for acute abdominal pain and an intra-abdominal mass in cryptorchid dogs with the CT features reported in this limited series. It should also be recognized that IATT is often secondary to testicular neoplasia.
Computed tomographic (CT) evaluation of medial iliac (MILN), internal iliac (IILN), and sacral (SLN) lymph nodes (LNs) in dogs provides vital staging information in certain neoplastic conditions. This retrospective study aimed to determine minimum transverse diameter (MinTD) and maximum transverse diameter (MaxTD) values for presumed normal iliosacral LNs and assess their utility in evaluating therapeutic response using response evaluation criteria in solid tumors (RECIST) v1.1. LN margins, number, and pre-contrast attenuation were also analyzed. The CT scans of 71 dogs were reviewed by an ACVR-certified veterinary radiologist. The MILNs were identified in 99% of dogs, predominantly bilaterally. The IILNs and SLNs were identified in 79% and 41% of dogs, respectively, with more variability in bilateral versus unilateral presence. Median values for MinTD/MaxTD were 4.2/7.4 mm for MILNs, 2.5/4.0 mm for IILNs, and 2.9/4.9 mm for SLNs. MinTD was <10 mm in all but one LN; MaxTD exceeded 10 mm in 19% of MILN sites and 1% of IILN sites. These results suggest that MinTD better reflects the RECIST v1.1 definition of non-pathologic LNs (i.e., LNs <10 mm) and is the recommended measurement when evaluating therapeutic response. Transverse diameters, except MILN MaxTD, were larger in intact dogs (p <= 0.013), and females had larger SLN MaxTD (p = 0.047). Aortic diameter and body weight were positively correlated (r = 0.7, p < 0.001), and dogs with an aortic diameter >8.6 mm had greater diameters for MILNs and IILNs (p <= 0.034). Separate MinTD values for IILNs and SLNs are presented herein, whereas prior studies reported them as a combined group.
A 2-year-old male entire Samoyed presented with 2 weeks of suspected lumbar pain, following an episode of compulsive hypersexual behavior towards other dogs. Computed tomography revealed a lobulated, enlarged left corpus cavernosum with a central non-enhancing, hypoattenuating region (-20 to 40 HU) and rim enhancement, surrounding ischiocavernosus muscle swelling, and left-sided bulbus penis hyperenhancement. Ultrasound showed an enlarged heterogeneous hyperechoic left corpus cavernosum. Ultrasound-guided needle aspiration for cytology, interpreted by a board-certified clinical pathologist, revealed mesenchymal proliferation and mild macrophagic inflammation, supporting a diagnosis of cavernositis. The dog was treated with anti-inflammatories and antibiotics with clinical resolution at a 4-week follow-up.
Canine cutaneous and subcutaneous mast cell tumors (MCTs) have highly variable clinical presentation, often mimicking benign lesions. This retrospective case-control study aimed to identify triple-phase computed tomography (CT) features that distinguish MCTs from benign lesions, with an emphasis on tumor size. Twenty-three MCTs (10 large [>= 3 cm]; 13 small [<3 cm]) and seven benign lesions were included. Qualitative features and CT attenuation values were compared among three groups by size and type. Large MCTs were primarily characterized by qualitative CT features. Significant differences among the three groups were observed in heterogeneous enhancement patterns, feeding vessels, infiltration, necrosis, and fat stranding. These features were most frequently observed in large MCTs. In contrast, small MCTs lacked these features but showed significantly higher CT attenuation values in the portal venous and equilibrium phases than benign lesions (p = 0.025 and 0.034, respectively). Receiver operating characteristic curve analysis for discriminating small MCTs from benign lesions yielded optimal cutoff values of 68.7 Hounsfield units (HU) for the portal venous phase (area under the curve [AUC] = 0.88; sensitivity, 92%; specificity, 71%) and 74.7 HU for the equilibrium phase (AUC = 0.85; sensitivity, 92%; specificity, 57%). In conclusion, despite the limited sample size, these findings suggest that triple-phase CT has clinical utility for differentiating MCTs from benign lesions. Qualitative patterns are particularly informative for large MCTs, whereas CT attenuation values in the portal venous and equilibrium phases may serve as objective adjunct indicators for identifying small MCTs that lack distinct morphological features.
