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Computed tomography is a valuable diagnostic technique in the clinical work-up of dogs with oropharyngeal trauma and bleeding. Traumatic extravasation can manifest as a pseudoaneurysm. A pseudoaneurysm is an extraluminal accumulation of blood that is contained by the adventitia layer or neighboring tissues. The purpose of this retrospective, multicenter, observational case series study was to describe the CT features in dogs with presumed oropharyngeal arterial pseudoaneurysm and its potential association with trauma. Imaging archives were searched for canine patients with head and neck CT studies showing visible extravasation of contrast-enhanced blood contained by soft tissue structures. Medical records of these patients were reviewed for oropharyngeal bleeding or trauma and reported. Four dogs met the inclusion criteria. CT findings included a well-defined, confined area of vascular contrast enhancement adjacent to the common carotid artery or its branches. The mean contrast enhancement in the corresponding artery and pseudoaneurysm lesion was similar, suggesting that these lesions represent active arterial extravasation. Four-dimensional CT was performed in one case and demonstrated contrast medium leaking from an artery and being contained by adjacent soft tissue structures. All dogs had a history and imaging findings consistent with oropharyngeal bleeding and trauma. Arterial pseudoaneurysm should be considered as a differential diagnosis in dogs with oral trauma and CT features of a well-defined, periarterial, strongly contrast-enhancing lesion., (© 2024 The Author(s). Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.)

Two adult dogs were presented at 25 and 30 days following tibial external skeletal fixator placement (case 1) and tibial plateau leveling osteotomy (case 2), respectively. Clinical signs at presentation for each of them included acute onset lethargy, non-weight-bearing lameness, and hemorrhage at the surgical site with large hematoma formation. On admission, emergency whole blood transfusion was required in case 2 with a preoperative packed cell volume of 13%. Both dogs were diagnosed with pseudoaneurysm of the cranial tibial artery based on color Doppler ultrasonography. Additionally, computed tomography angiography was performed in one dog. Surgical treatment of the dogs included ligation of the cranial tibial artery supplying the pseudoaneurysm and curettage of hematoma. The surgery was completed without complications in case 1, but case 2 experienced inadvertent rupture of pseudoaneurysm with significant blood loss, which required another whole blood transfusion during the procedure. Both dogs had excellent functional recovery with no recurrence of clinical signs. We hypothesized that pseudoaneurysms were primarily caused by trauma secondary to placement of surgical implants or osteotomy. For orthopedic surgeons, it is important to recognize clinical signs of a potential tibial arterial pseudoaneurysm, as early surgical intervention may prevent loss of limb or life., (© 2024 by American Animal Hospital Association.)

Objectives: To describe multidetector CT and ultrasonographic characteristics of abdominal arterial pseudoaneurysms (segmental dilatations of an artery with a ruptured tunica intima) arising secondary to systemic mycosis in dogs., Materials and Methods: Retrospective study on dogs with confirmed histological diagnosis of a fungal pseudoaneurysm and the availability of multidetector CT or ultrasound images., Results: At the time of admission, the three dogs included in this study demonstrated segmental arterial dilation, irregular arterial wall thickening, and increased echogenicity or attenuation within the local perivascular fat on ultrasound and multidetector CT images. Follow-up examinations revealed progressive increase in arterial wall thickening and saccular dilation with formation of a pseudoaneurysm in affected vessels of two dogs., Clinical Significance: Multidetector CT and ultrasonography can be useful imaging modalities in the diagnosis and monitoring of abdominal arterial pseudoaneurysms caused by systemic mycosis., (© 2020 British Small Animal Veterinary Association.)

A 12 yr old male neutered beagle was presented on transfer to the intensive care unit with severe anemia, thrombocytopenia, and bruising detected 1 day after undergoing tibial plateau leveling osteotomy surgery. The patient had undergone extra-capsular stifle stabilization surgery 14 wk prior to treat ligament disease in the same knee. Laboratory testing and treatment for anemia, presumptive immune-mediated thrombocytopenia, and possible hemostatic disorder was initiated. A persistent anemia, progressive thrombocytopenia, and the development of a firm swelling and neurologic impairment in the limb raised concerns for compartment syndrome (CS). A musculoskeletal ultrasound revealed a large aneurysm in the caudal thigh surrounded by abnormal muscle tissue. The patient underwent amputation of the limb and recovered without further complication. Pathology findings were consistent with the development of femoral CS secondary to a ruptured peripheral arterial aneurysm or a pseudoaneurysm. A consumptive thrombocytopenia and regenerative anemia were attributed to periodic or progressive thrombosis of the vessel and regional hemorrhage. Postoperative CS can develop in combination with peripheral arterial aneurysm or pseudoaneurysm, and screening for vascular abnormalities as well as CS should be considered in complicated recovery from orthopedic surgery with compatible clinical signs including progressive soft tissue swelling, persistent anemia, and thrombocytopenia.

An 8-y-old female rhesus macaque (Macaca mulatta) presented for swelling of the left lower limb distal to the inguinal region and associated with the femoral artery. Physical and ultrasound examinations suggested an arteriovenous fistula combined with a pseudoaneurysm. After review of possible treatment options, we determined that open surgical repair was the best course of action. The pseudoaneurysm and arteriovenous fistula were surgically resected, and the macaque recovered without complication.

A 12-year-old, castrated male, domestic long-haired cat experienced massive haemorrhage associated with an incision of a swelling on the neck 2 weeks after right-sided ventral bulla osteotomy. Emergent control of haemorrhage was gained through unilateral carotid artery ligation. Cardiopulmonary resuscitation was provided in conjunction with massive blood transfusion. The cat made an unremarkable recovery. Carotid artery pseudoaneurysm due to surgical disruption of the carotid artery during ventral bulla osteotomy, specifically through the use of self-retaining retractors, was suspected. This case highlights the development of pseudoaneurysm as a potential complication of head and neck surgery, and additionally describes a case of massive transfusion in a cat., (© 2015 British Small Animal Veterinary Association.)

Aortic rupture in horses is a rare condition. Although it is relatively common in the Friesian breed, only limited histopathologic information is available. Twenty Friesian horses (1-10 years old) were diagnosed with aortic rupture by postmortem examination. Ruptured aortic walls were analyzed with histology and immunohistochemistry. Based on the histologic and immunohistochemical findings, these cases were divided into 3 groups: acute (n = 4, 20%), subacute (n = 8, 40%), and chronic (n = 8, 40%). Features common to samples from horses in all groups included accumulation of mucoid material; disorganization and fragmentation of the elastic laminae; aortic medial smooth muscle hypertrophy; and medial necrosis of varying degrees, ranging from mild and patchy in the acute cases to severe midzonal necrosis in the chronic cases. Inflammation, most likely secondary to medial necrosis, varied from predominantly neutrophilic infiltrates in the media and periadventitial tissue in the acute group to the presence of mainly hemosiderophages in the periadventitial tissue in the chronic group. Medial fibrosis with aberrant collagen morphology was seen in the subacute group and, more commonly, in the chronic group. Only minimal changes were seen in the aortic vasa vasorum. Smooth muscle hypertrophy and accumulation of mucoid material were not related to the age of the lesions. The findings of this study suggest that a connective tissue disorder affecting elastin or collagen in the aortic media is potentially the underlying cause of aortic rupture in Friesian horses., (© The Author(s) 2014.)

Objective: To describe successful transarterial coil embolization of a palatine artery pseudoaneurysm that extended into the caudal maxillary sinus of a gelding., Study Design: Clinical report., Animal: A 24-year-old Morgan gelding with right-sided epistaxis., Methods: The right maxillary sinus was imaged by radiography, computed tomography, and sinoscopy. Angiography was performed to locate the source of bleeding, and transarterial coil embolization of a right palatine artery pseudoaneurysm was performed., Results: There was some mucoid nasal discharge and an intermittent cough postoperatively. No epistaxis was seen after embolization. There was moderate swelling of the surgical incision over the mid-cervical common carotid artery. The horse was discharged from the hospital 4 days after surgery, and had been doing well, with no signs of bleeding, for 2 months postoperatively. The horse had acute colic secondary to a strangulating lipoma at 2 months and was euthanatized after exploratory celiotomy. Placement of embolization coils in the right palatine artery was confirmed by CT and necropsy., Conclusions: Severe epistaxis in the horse may be caused by a ruptured major palatine artery pseudoaneurysm. Occlusion of this vessel can be successfully accomplished by transarterial coil embolization., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Unlabelled: CLINICAL SUMMARY: A 4-month-old female intact domestic shorthair cat presented to Kansas State University Veterinary Medical Teaching Hospital for investigation of a large, firmly adhered mass in the left mid-cervical region that developed after phlebotomy performed at the referring veterinarian's clinic. Ultrasound examination of the mass revealed a cystic structure in communication with the left carotid artery, with bidirectional blood flow through the area. A diagnosis of pseudoaneurysm secondary to accidental needle penetration of the carotid artery during jugular venepuncture was made., Outcome: Strict cage rest and pain management resulted in complete resolution of clinical and ultrasonographic signs in this cat.

Objective: To report the diagnosis and treatment of a radial artery pseudoaneurysm in a cat., Study Design: Clinical report., Animal: Maine Coon cat (8-year-old neutered male)., Methods: Ultrasonographic and angiographic examination of a fluctuant, nonpainful, 3 cm × 1.5 cm subcutaneous swelling on the craniomedial distal aspect of the right radius that occurred 40 days after suspected cat bite trauma was consistent with a radial artery pseudoaneurysm. After ligation of the radial artery proximal to the lesion, the pseudoaneurysm was surgically excised., Results: The excised tissue had hemorrhage and fibrin surrounded by a thick fibrous granulating capsule of variably mature fibroblasts and focal areas of inflammatory cells (lymphocytes, plasma cells, and macrophages) consistent with a pseudoaneurysm. Surgical excision resulted in resolution of clinical signs., Conclusions: Ultrasonography enabled prompt, noninvasive diagnosis of pseudoaneurysm. Angiography or computed tomography may be useful to aid diagnosis and assess the collateral blood supply to the manus before surgical treatment., (© Copyright 2011 by The American College of Veterinary Surgeons.)

The ultrasound and computed tomography findings of a retroperitoneal pseudoaneurysm associated with a grass awn are described in a 10-month-old dog. Ultrasound was used to localize the lesion and surrounding reaction as well as to determine its relationship with the celiac artery, but inadequate Doppler settings hindered the diagnosis of its vascular nature. Dual phase CT enabled further characterization, particularly its close relationship with the major retroperitoneal vessels. The imaging examination was fundamental in recommending nonsurgical therapy. The dog died as a consequence of the rupture of this pseudoaneurysm. A grass awn was confirmed.

An 8-month-old Arabian-warmblood cross colt was evaluated for overt hematuria. The horse was severely anemic on presentation. A unilateral intrarenal vascular anomaly with unilateral pyelonephritis was diagnosed. Nephrectomy was attempted but was unsuccessful, and postmortem examination demonstrated the presence of an intrarenal pseudoaneurysm.