David J. Reese

Comparison of computed tomographic angiography and ultrasonography for the detection and characterization of portosystemic shunts in dogs.

The purpose of this retrospective study was to compare the accuracy of computed tomographic angiography (CTA) and abdominal ultrasonography in detecting and characterizing portosystemic shunts (PSS) in dogs. Medical records of 76 dogs that underwent CTA and/or abdominal ultrasonography suspected to have PSS were reviewed. Presence or absence, and characterization of PSS (when present) on CTA were reviewed by a board-certified veterinary radiologist that was blinded to the clinical findings. The abdominal ultrasonography findings were reviewed from the medical records. Visualization and description of the origin and insertion of PSS on CTA and abdominal ultrasonography were related with laboratory, surgical, or mesenteric portographic confirmation of the presence or absence of PSS. The sensitivity for detection of PSS with CTA (96%) was significantly higher than abdominal ultrasonography (68%; P < 0.001). The specificities for CTA and abdominal ultrasonography were 89% and 84%, respectively (P = 0.727). Computed tomographic angiography detected the correct origin in 15 of 16 dogs and correct insertion in 15 of 16 dogs with congenital PSS. Abdominal ultrasonography detected the correct origin in 24 of 30 dogs and correct insertion in 20 of 33 dogs with congenital PSS. Multiple acquired PSS were seen in four of five dogs and in one of six dogs on CTA and abdominal ultrasonography, respectively. Computed tomographic angiography was 5.5 times more likely to correctly ascertain the presence or absence of PSS when compared to abdominal ultrasonography (P = 0.02). Findings indicated that CTA is a noninvasive diagnostic modality that is superior to abdominal ultrasonography for the detection and characterization of PSS in dogs.

Multiple Congenital PSS in a Dog: Case Report and Literature Review

A 4 yr old spayed female mixed-breed dog presented with a 2 yr history of recurring increases in liver enzymes. Two congenital portosystemic shunts (PSSs) were identified using computed tomography (CT) angiography, which included a portoazygous and portorenal extrahepatic shunt. Double right renal veins were also identified. The shunts were successfully identified and attenuated with cellophane banding. Multiple congenital PSS is a rare phenomenon, but should be considered during exploratory laparotomy for PSS and in dogs with poor response to surgical attenuation of a single PSS. CT proved to be a crucial part of accurate diagnosis and surgical planning for this dog with multiple congenital PSS.

Use of an interlocking nail-hybrid fixator construct for distal femoral deformity correction in three dogs

Our purpose was to report the use of an interlocking nail-hybrid external fixator construct to correct distal femoral deformities in three dogs. Radiographs, computed tomography and a three-dimensional model were used to plan the surgical procedure. A femoral osteotomy or ostectomy was performed at the level of the centre of rotation of angulation in all three dogs. Angular and rotational deformities were corrected acutely. Distraction osteogenesis was performed to lengthen each femur postoperatively. All three dogs had additional anatomic abnormalities of the affected hindlimb complicating the correction of the distal femoral deformity. While the interlocking nail-hybrid fixator construct allowed for stable distraction of the femur, all three dogs developed complications during the postoperative convalescent period, and each had some degree of residual lameness. Lengthening the femur following acute deformity correction is problematic and additional experimental and clinical studies are warranted to decrease postoperative morbidity and improve functional results.

Intra- and interobserver variability of board-certified veterinary radiologists and veterinary general practitioners for pulmonary nodule detection in standard and inverted display mode images of digital thoracic radiographs of dogs.

OBJECTIVE To determine intra- and interobserver variability of 2 veterinary radiologists and 2 veterinary general practitioners for detection of pulmonary nodules in standard and inverted (reversed grayscale) displays of digital thoracic radiographs of dogs. DESIGN Evaluation study. SAMPLE 114 sets of 3-view (right lateral, left lateral, and ventrodorsal or dorsoventral views) digital thoracic radiographs from 114 dogs. PROCEDURES 2 experienced board-certified veterinary radiologists and 2 experienced veterinary general practitioners individually evaluated 114 randomized sets of radiographs. Pulmonary nodules were present in radiographs of 60 of 114 dogs. Each reviewer examined all images in standard or inverted display mode and scored nodule detection on a confidence scale of 1 to 5. After ≥ 2 months, the same individuals evaluated the same images in the remaining display mode. Intraobserver agreement for each display mode was determined via a κ statistic; results between the 2 groups of reviewers were compared via receiver operator curve analysis. RESULTS There was no significant intraobserver variability in pulmonary nodule detection between the 2 display modes. Detection accuracy for board-certified radiologists was significantly greater than that of veterinary general practitioners for both display modes. Near-perfect intraobserver agreement was detected between the 2 display modes for board-certified radiologists, whereas moderate to slight intraobserver agreement was detected for the veterinary general practitioners. CONCLUSIONS AND CLINICAL RELEVANCE Detection of pulmonary nodules in digital thoracic radiographs was comparable, whether a standard or inverted mode was used for evaluations. However, the board-certified radiologists had greater detection accuracy than did veterinary general practitioners.

Use of a circular fixator construct for metacarpal fracture stabilisation in a fawn

FRACTURES of the metacarpus and metatarsus are the most reported fractures in deer species (Nisbet and others 2010). While comminuted appendicular fractures in adult deer have a guarded prognosis, similar fractures in juvenile deer are associated with a better prognosis because of tractability and fast healing times (Mills and others 1996, Nisbet and others 2010). Circular fixators have become an accepted modality for stabilising fractures of the distal extremities in domestic species including dogs, cats (Lewis and others 1999, Anderson and others 2003) and growing cattle (Aithal and others 2004, Singh and others 2007, Bilgili and others 2008) because they can be applied in a closed fashion, mitigating iatrogenic surgical trauma, and allow for axial micromotion, which promotes callus formation (Lewis and others 1999, Singh and others 2007) and rapid healing (Bilgili and others 2008). Although evaluated in other species, the utility of circular fixators for fracture repair in deer has not been evaluated. In deer, there are reports of successful appendicular fracture stabilisation with linear fixators (Mills and others 1996, Nisbet and others 2010) and, more recently, a hybrid linear-circular fixator (Phelps and others 2010). This case report describes the use of a circular fixator construct as an alternative method of stabilising for a comminuted metacarpal fracture in a white-tailed deer (Odocoileus virginianus) fawn. A two-month-old, 8 kg, female white-tailed deer fawn presented with swelling, crepitus and instability of the right metacarpus. Radiographs showed comminuted dorsolaterally displaced mid-diaphyseal fractures of the third and fourth metacarpal bones with well-defined fissures extending from the fracture margins (Fig 1a, b). Surgical stabilisation was …

Digital Radiography for the Equine Practitioner: Basic Principles and Recent Advances

As availability increases and cost decreases, digital radiograph systems become more common in equine practice. Technological advances provide an array of choices for the equine practitioner considering purchase. Two classes of systems are available: computed radiography and flat-panel systems (direct radiography). Image processing encompasses all manipulations performed on an image at acquisition and can have a profound effect on the final digital radiograph. Consideration should be given to the type of display monitor because many options are now available. The type of display monitor and the viewing environment have an effect on interpretation performance.

Associations between 'valentine' heart shape, atrial enlargement and cardiomyopathy in cats

‘Valentine’ heart shape is a common qualifier used in veterinary radiology to describe a cardiac silhouette with focal enlargement at the level of the base of the heart in feline patients. Anecdotally, this sign has been thought to be related to biatrial enlargement and also to hypertrophic cardiomyopathy (HCM). However, to our knowledge, there has been no study performed to assess the association between cardiac chamber enlargement and cardiac disease with the ‘valentine’-shaped heart. The aim of this study was to verify the association between the ‘valentine’ heart shape observed in ventrodorsal thoracic radiographs and the presence of singular or combined cardiac chamber enlargement, and also the presence and type of cardiomyopathy (CM) in cats. A search of the database of the Small Animal Veterinary Hospital of the University of Florida for cats with a radiology report of thoracic radiographs that contained the words ‘valentine’ and ‘biatrial’, and echocardiography performed within 1 week, was undertaken; 41 cases met the inclusion criteria. Eighty-two percent of the cats of the study sample had some form of CM. The ‘valentine’ heart shape was associated with biatrial enlargement in 41% of the patients in our study sample that had some form of CM and just 8% of cases diagnosed with HCM, suggesting that the ‘valentine’ heart shape has a low association with HCM or biatrial enlargement; however, it should be considered a sign of feline CM.

Parasites in 30 Captive Tokay Geckos, Gekko gecko

ABSTRACT Twelve species of parasites were recovered from recently imported Tokay geckos, Gekko gecko. These included one cestode species, Oochoristica rachiensis, two trematode species, Mesocoelium monas and Paradistomum geckonum, six nematbde species, Pharyngodon kuntzi, Skrjabinodon sp., Parapharyngodon sp. Meteterakis longispiculata, Physalopteroides sp., and Strongyloides sp., one acanthocephalan species, Porrorchis sp., one pentastomid species, Raillietiella affinis, and one coccidian species, Eimeria tokayae. Of the 20 species previously reported infecting Tokay geckos, eight were identified in this study. Two species are new host records and two others are undescribed species. The most common helminths recovered were Pharyngodon kuntzi, Meteterakis longispiculata, and Raillietiella affinis.

Bifocal Femoral Deformity Correction and Lengthening Using a Circular Fixator Construct in a Dog

A 7 mo old male rottweiler was evaluated for a right hind limb lameness caused by malunion of a Salter-Harris type II fracture. Radiographs and computed tomography (CT) revealed that the right distal femur had valgus, procurvatum, external rotation, and was 35% (70 mm) shorter than the contralateral femur. Distal femoral wedge ostectomies were performed to acutely correct the angular and rotational deformities. Lengthening of the femur was accomplished by distraction osteogenesis performed over 53 days at a second, proximal diaphyseal osteotomy using a circular fixator construct. This bifocal approach yielded approximately 30 mm of femoral lengthening and a confluent column of regenerate bone that bridged the distraction gap. When evaluated 14 mo after surgery, the dog held the right hip, stifle, and hock in a slightly extended posture when standing and had a subtle asymmetric hind limb gait. The stride of the right hind limb was slightly shortened with compensatory circumduction of the left hind limb during the swing phase of the stride.

Computed tomography angiography of bilateral peripheral pulmonary arterial stenoses in a dog.

Computed tomographic angiography (CTA) is a useful diagnostic modality that is becoming more widely available in veterinary medicine. Its three-dimensional imaging capabilities allow a template for planning surgical procedures, accurate lesion measurements, and it is considerably less expensive than other comparable modalities. Selective CTA is described here, in a case of canine bilateral peripheral pulmonary artery stenoses.