Computed tomographic appearance of choanal atresia in an alpaca cria.

A 6-hour-old alpaca cria was admitted for evaluation of respiratory distress since birth. Contrast radiography confirmed the presence of bilateral choanal atresia, and computed tomography (CT) evaluation was planned to aid in the surgical treatment. Due to deterioration in the cria's condition, euthanasia was performed prior to the CT examination. Postmortem CT examination was performed to determine the appearance of choanal atresia. The embryology and CT appearance of choanal atresia is discussed.

Persistent post-laparoscopy pneumoperitoneum.

BACKGROUND: Persistent pneumoperitoneum after a laparoscopic operation can represent either residual postoperative pneumoperitoneum or free intraperitoneal gas released from the gastrointestinal tract. This animal study was conducted to better characterize the extent and duration of postoperative pneumoperitoneum as detected by computed tomography (CT). METHODS: Five pigs underwent cholecystectomy, four laparoscopically and one open. All pigs were followed serially with upright chest radiographs and abdominal CT scans beginning immediately postoperatively and continuing daily until resolution of pneumoperitoneum as detected by both imaging modalities. All radiographs and CT scans were reviewed by dedicated radiologists who reported the extent and duration of pneumoperitoneum in a blinded fashion. RESULTS: Pneumoperitoneum resolved on upright chest radiographs in all five pigs by or on postoperative day 1. Serial CT scans demonstrated that the laparoscopic group had either resolution of pneumoperitoneum or minimal persistence of free intraperitoneal gas by postoperative day 2. In contrast, the single pig in the open group had CT evidence of persistent pneumoperitoneum through postoperative day 6. CONCLUSIONS: In the pig model, small pockets of free intraperitoneal gas detected by CT scanning are expected to resolve by postoperative day 2 following laparoscopic surgery. Persistence of pneumoperitoneum beyond this interval is abnormal and may represent a perforated viscus. Whereas a prospective CT imaging study in humans is not ethically feasible, we believe that parallel conclusions between the pig and human may be drawn.

Comparison of three radiographic methods for diagnosis of hip dysplasia in eight-month-old dogs.

OBJECTIVE: To compare the accuracy of the extended-hip radiographic (EHR) score, the distraction index (DI), and the dorsolateral subluxation (DLS) score for identifying hip dysplasia in dogs at 8 months of age. DESIGN: Cohort study ANIMALS: 129 Labrador Retrievers, Greyhounds, and Labrador Retriever-Greyhound crossbreds. PROCEDURE: Radiography was performed when dogs were 8 months of age. Dogs were euthanatized at 8 to 36 months of age; hip dysplasia was diagnosed at the time of necropsy on the basis of results of a gross examination of the articular cartilage of the hip joints for signs of osteoarthritis. RESULTS: The EHR score, DI, and DLS score at 8 months of age were all significantly correlated with degree of cartilage degeneration at necropsy. Sensitivity and specificity of using EHR score at 8 months of age to diagnose hip dysplasia (scores > 3 were considered abnormal) were 38 and 96%, respectively; sensitivity and specificity of using DI (values > 0.7 were considered abnormal) were 50 and 89%; and sensitivity and specificity of using DLS score (scores < 55% were considered abnormal) were 83 and 84%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that specificities of the 3 methods for diagnosing hip dysplasia in dogs at 8 months of age were similar. However, the DLS score had higher sensitivity, indicating that there were fewer false-negative results.

Influence of patient positioning on sensitivity of mesenteric portography for detecting an anomalous portosystemic blood vessel in dogs: 34 cases (1997-2000).

OBJECTIVE: To determine whether sensitivity of detecting an anomalous portosystemic blood vessel during operative mesenteric portography varied with patient positioning. DESIGN: Retrospective study. ANIMALS: 34 dogs with a portosystemic shunt diagnosed via scintigraphy or surgery. PROCEDURE: Portograms were evaluated for a portosystemic blood vessel. Sensitivity was calculated from results obtained with dogs in left lateral, right lateral, and dorsal recumbency and from results obtained with dogs in 2 or 3 positions. Differences in sensitivity among positions and between 2 examiners were evaluated. RESULTS: Sensitivity was 85, 91, and 100% in dorsal, right lateral, and left lateral recumbency, respectively. Sensitivity was lower in dorsal recumbency than in left lateral recumbency, although differences were not significant. There was no significant difference between sensitivity of results obtained in dorsal and right lateral recumbency or right lateral and left lateral recumbency. Sensitivity for combined right lateral and dorsal positions was 97%, which was better than that in dorsal recumbency alone, although the difference was not significant. Because sensitivity in left lateral recumbency was 100%, there was no need to evaluate the improvement obtained by combining the result of this position with the results of other positions. CONCLUSION AND CLINICAL RELEVANCE: Results of mesenteric portography varied with patient positioning. The optimal position varied among patients but left lateral recumbency may be better and dorsal recumbency worse. Sensitivity may be improved by performing the test with the patient in orthogonal recumbent positions.

Repeatability of dorsolateral subluxation scores in dogs and correlation with macroscopic appearance of hip osteoarthritis.

OBJECTIVE: To determine whether dorsolateral subluxation (DLS) scores in young dogs could be used to reliably predict which dogs would develop evidence of hip osteoarthritis and whether DLS scores measured at various ages correlated with each other. ANIMALS: 129 Labrador Retrievers, Greyhounds, and Labrador Retriever-Greyhound crossbreds. PROCEDURES: DLS scores were measured on radiographs taken at 4, 8, and 12 months of age and at necropsy (8 to 36 months of age). At necropsy, the hip joints were examined macroscopically and a score assigned for degree of cartilage degeneration. RESULTS: DLS scores at 4 (n = 35, r(s) = -0.62), 8 (n = 106, r(s) = -0.54), and 12 (n = 15, r(s) = -0.87) months of age were significantly correlated with cartilage degeneration scores, and DLS scores at 8 months of age were significantly correlated with scores obtained at the time of necropsy (n = 39, r(s) = 0.87). The DLS scores at 4 months of age were significantly different from scores at 8 months of age, but scores did not differ significantly thereafter. Likelihood ratios for cartilage lesions for low (< 45%), intermediate (> or = 45 but < or = 55%), and high (> 55%) DLS scores at 8 months of age were 8.0, 2.6, and 0.2, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that DLS score at 8 months of age was a reasonable, albeit imperfect, predictor of the condition of the hip joint cartilage at necropsy. Thus, the DLS method might be useful for early identification of dogs with hip dysplasia.

Glomerular filtration rate and renal volume in dogs with congenital portosystemic vascular anomalies before and after surgical ligation.

Glomerular filtration rate (GFR) and renal volume were evaluated in dogs with confirmed portosystemic vascular anomalies (PSVA) before and after surgical ligation of their PSVA. Pre- and postligation CBC, serum biochemistry, urinalysis, abdominal ultrasonography with measurement of renal volume, and per rectal scintigraphy were performed to document resolution of abnormalities consistent with portosystemic shunting. GFR was estimated by plasma 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) clearance before (n = 21) and after (n = 12) surgical correction of PSVA. Preligation 99mTc-DTPA GFR was increased (median, 5.64 mL/minute/kg; range, 3.53-8.49 mL/minute/kg; reference range, 2.83-4.47 mL/minute/kg) in 81% (17/21) of dogs. Postligation 99mTc-DTPA GFR decreased in all 12 evaluated dogs (median change = -42%; P < .001). Preligation renal volume was above the reference range for the left and right kidneys in 71% (10/14) and 69% (11/16) of dogs evaluated, respectively. Right renal volume decreased significantly (n = 5; median change, -45%; P = .03) after surgical ligation of PSVA. These findings document increased GFR and renal volume in dogs with PSVA, which may explain in part the low blood urea nitrogen and serum creatinine concentrations encountered in these dogs. Knowledge of changes in GFR associated with PSVA ligation may prove helpful in the anesthetic, drug, and dietary management of affected dogs.

An outcrossed canine pedigree for linkage analysis of hip dysplasia.

Canine hip dysplasia (CHD) is a prevalent, debilitating, polygenic disease characterized by hip subluxation and laxity which results in osteoarthritis. We are developing an informative pedigree for linkage analysis of CHD. The seven greyhound founders had excellent hip conformation with high dorsolateral subluxation scores (percentage of femoral head covered by the dorsal acetabulum in a weight-bearing position) of 66 +/- 4% (mean +/- SD averaged over both hips) and low hip distraction (laxity) indices of 0.14 +/- 0.08. Nine greyhounds bred on site had radiographic evidence of ossification in the capital femoral chondroepiphysis at 7.7 +/- 0.9 days of age. At 8 months of age they had a mean distraction index of 0.24 +/- 0.08 and dorsolateral subluxation score of 76 +/- 1%. Of the four dysplastic Labrador retriever founders, three had mean age at onset of capital femoral chondroeplphyseal ossification of 20 +/- 7 days of age n = 3) and a mean distraction index of 0.46 +/- 0.1 accompanied by hip osteoarthritis. Thirty-four F1s had mean onset of capital femoral ossification (10.7 +/- 4.0 days of age) and mean dorsolateral subluxation scores (61 +/- 12%) similar to the greyhound founders, but distraction indices (0.42 +/- 0.2) more similar to the Labrador retriever founders. One F1 had CHD radiographically but none of 20 F1s had osteoarthritis at necropsy at 10 months of age. These data suggested that maximum passive laxity (as measured by the distraction index) and normal osseous conformation (as indicated by a high dorsolateral subluxation score) were both dominant traits and were controlled by separate quantitative trait loci (QTL). Forty-three back-crosses between F1s with the highest hip laxity and greyhound founders had mean onset of capital femoral ossification at 9.9 +/- 2.6 days of age. Of 10 dogs in the backcross generation that have reached 8 months of age, 2 had palpable subluxation without marked CHD radiographically. The mean distraction index of these dogs was 0.36 +/- 0.16 and the dorsolateral subluxation score was 65 +/- 5%. Although dogs in the backcross generation that were three-quarter greyhound had a broad range of hip laxity, a protective effect of the greyhound QTLs for good osseous conformation has mitigated thus far against subluxation and CHD.

Comparison of measurements of dorsolateral subluxation of the femoral head and maximal passive laxity for evaluation of the coxofemoral joint in dogs.

OBJECTIVE: To determine whether dorsolateral subluxation (DLS) of the femoral head reflects osseous conformation of the coxofemoral (hip) joint and represents a property distinct from maximum passive laxity of the hip joint in dogs. ANIMALS: 14 Labrador Retrievers, 16 Greyhounds, 58 Greyhound-Labrador Retriever mixed-breed dogs, and 1 Rottweiler. PROCEDURES: DLS of the femoral head (DLS score) and passive laxity of the hip joint (distraction index) were determined radiographically in 3 groups of dogs: not treated (167 joints of 84 dogs); before and after injecting 2 ml of hyaluronan into 25 hip joints of 13 dogs; and before and after unilateral triple pelvic osteotomy in 5 dogs. Results of the 2 methods were compared for each group. RESULTS: In untreated dogs, the correlation coefficient (r) of DLS score versus distraction index was -0.73 and -0.69 for 84 left and 83 right hip joints, respectively. Mean coefficient of determination (r2) for both hips was 0.5. Mean DLS score did not differ before and after intra-articular injection of hyaluronan into either hip joint, whereas mean distraction index increased significantly after intra-articular injection. Unilateral triple pelvic osteotomy resulted in a significant increase in DLS score, compared with values obtained before surgery. However, distraction index before and after surgery did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE: The DLS test assesses the congruity of the acetabulum and the femoral head in a canine hip joint and thus represents a characteristic distinct from maximum passive laxity. The DLS score and the distraction index evaluate different components of hip joint stability.

Cullen's sign and haemoglobinuria as presenting signs of retroperitoneal haemorrhage in a dog.

Haemoglobinuria and periumbilical discoloration (also known as Cullen's sign) are clinical signs uncommonly reported in veterinary patients. This report describes a case of retroperitoneal haemorrhage in a dog, associated with haemoglobinuria and Cullen's sign. To the authors' knowledge, these clinical signs have not previously been reported singularly or in combination with retroperitoneal haemorrhage in dogs. A neutered male Shetland sheepdog, which was presented for haematuria, also had an abdominal mass, abdominal pain and a large area of periumbilical discoloration. Laboratory studies determined that haemoglobinuria was the cause of the red-coloured urine. Abdominal radiographs suggested a splenic mass and a coeliotomy was performed. During the induction and throughout the anaesthetic period the dog was hypertensive and a large haematoma originating from the right retroperitoneal space was identified at surgery. The cause of the haemorrhage was uncertain but a ruptured phaeochromocytoma was thought possible on the basis of the persistent hypertension and the location of the haemorrhage.

Dorsolateral subluxation of hip joints in dogs measured in a weight-bearing position with radiography and computed tomography.

OBJECTIVE: develop a radiographic procedure to measure dorsolateral subluxation (DLS) of the femoral head in canine coxofemoral (hip) joints in a weight-bearing position. STUDY DESIGN: DLS measured on a radiographic projection was compared with DLS measured on computed tomography (CT) images of hip joints in a weight-bearing position. ANIMALS: A total of 24 dogs of varying ages were examined including Labrador retrievers, greyhounds, and Labrador-greyhound crossbreeds. METHODS: Anesthetized dogs were placed in sternal recumbency in a kneeling position in a foam rubber mold. The stifles were flexed and adducted with the femora perpendicular to, and in contact with, the table. To test for DLS, dogs were imaged in this weight-bearing position (DLS test) with routine radiography and CT. For each hip, the DLS score was determined by measuring the percentage of the femoral head medial to the lateralmost point of the cranial acetabular rim on the dorsoventral radiographic projection and the lateralmost point of the central, dorsal acetabular rim on the CT image. Higher DLS scores indicated better coverage of the femoral head by the acetabulum. DLS scores were compared with the distraction index (DI) by grouping joints according to their probability of developing osteoarthritis (OA) as predicted by the DI. RESULTS: The DLS score in the new position ranged from 29% to 71% for radiography and 15% to 59% for CT. Joints classified as OA unsusceptible had a mean score of 64% +/- 1.5% for radiography and 55% +/- 0.8% for CT (n = 10); hip joints having a high probability of developing OA had a score of 39% +/- 2.6% for radiography and 26% +/- 1.9% for CT (n = 8). When the DLS test was repeated on the same dogs at a different time, the intraclass correlation coefficient for the DLS score on the radiographs was 0.85 (left hip) and 0.89 (right hip). There was a strong correlation (r = .89 for both hips) between the DLS score measured on the weight-bearing radiograph and the CT image. A strong correlation also was observed between the DLS score and the DI (r = -.87). The DLS scores for OA unsusceptible joints and joints with a high probability of developing OA were significantly different (P < .05). CONCLUSIONS AND CLINICAL RELEVANCE: The DLS test can be performed with CT or routine radiography to measure variable amounts of DLS in weight-bearing hip joints oriented similarly to those of a standing dog. After additional long-term follow-up studies evaluating the development of OA and breed effects are performed, the DLS method may prove useful in studies of normal and abnormal hip joint development related to canine hip dysplasia.

Contrast radiography of the lower urinary tract in the management of obstructive urolithiasis in small ruminants and swine.

Contrast radiographic visualization of the small ruminant and porcine lower urinary tract is an infrequently used modality for the evaluation and management of obstructive urolithiasis. The administration of contrast medium through a tube cystostomy catheter used to divert urine flow until the resolution of the obstruction may provide an easy method to evaluate the status of the urethral obstruction. Contrast fluoroscopy is utilized to monitor and visualize therapeutic flushing of the urethra. A review of 26 patients seen at the Veterinary Medical Teaching Hospital suggested that among the radiographic techniques used, positive contrast normograde cystourethrography through the tube cystostomy catheter allowed the best visualization of the lower urinary tract structures and enabled assessment of the resolution of the obstructive lesion.

Suspected microscopic hepatic arteriovenous fistulae in a young dog.

Portal hypertension can develop from any disorder that obstructs portal blood flow and may cause ascites in young dogs. Anomalous hepatic arteriovenous (AV) connections are rare but should be suspected in any young dog with portal hypertension or ascites. All previous reports of dogs with hepatic AV fistulae have documented macroscopic connections between the arterial and venous systems. Identical clinical signs and histopathologic findings can develop in dogs in which a macroscopic hepatic AV connection cannot be detected. Microscopic AV connections may be responsible for clinical signs in these dogs.

Evaluation of somatostatin analogues for the detection and treatment of gastrinoma in a dog.

Gastrinomas in dogs are difficult to diagnose, localise and treat. In humans, somatostatin analogues have improved localisation and treatment of gastrinomas. The somatostatin analogues pentetreotide and octreotide were evaluated for the detection and treatment of gastrinoma in a dog. 111indium-pentetreotide scintigraphy revealed multiple areas of activity in the patient's mid-ventral abdomen which were consistent with masses in the pancreas and liver at laparotomy. Immunohistochemistry, electron microscopy and binding of 125I-[Tyr3]-octreotide in vitro confirmed the lesion as a gastrinoma which expressed somatostatin receptors. Octreotide at doses of 2, 4 and 8 micrograms/kg caused transient decreases in circulating gastrin. Plasma somatostatin peaked at one hour after octreotide and was still detectable at four and six hours after administration of octreotide. Combination therapy with famotidine, omeprazole, sucralfate and increasing doses of octreotide allowed patient survival for 14 months.

Characterization of hepatoportal microvascular dysplasia in a kindred of cairn terriers.

Hepatoportal microvascular dysplasia (MVD), a congenital disorder of the hepatic vasculature, is described in a kindred of Cairn Terrier dogs. Cairn Terrier dogs (n = 165) were evaluated using the serum bile acid test. Affected dogs, identified by abnormal fasting or postprandial serum bile acid concentrations, were divided into 2 groups. Group 1 dogs (n = 147) were used for pedigree analysis. Group 2 dogs (n = 18) were characterized on the basis of history, physical examination, clinicopathologic studies, diagnostic imaging of the liver and portal circulation, and hepatic histopathology. Group 2 contained control dogs (n = 2), dogs with hepatoportal MVD (n = 11), and dogs with macroscopic portosystemic vascular anomalies (PVSA) (n = 5). With the exception of high serum bile acid concentrations, dogs with hepatoportal MVD were indistinguishable from control dogs on the basis of history, physical examination, clinicopathologic findings, survey abdominal radiography, abdominal ultrasound, or transcolonic scintigraphy. Contrast portography in dogs with MVD revealed abnormalities of terminal twigs of the portal vasculature with out large intrahepatic or extrahepatic shunting vessels. Histopathologic abnormalities in dogs with hepatoportal MVD were similar to those reported for dogs with PSVA. Pedigree analysis suggested an autosomal inheritance for MVD. Dogs with MVD had high serum bile acid concentrations, abnormal indocyanine green clearance, and hepatic pathology suggestive of PSVA, but they lacked characteristic clinical findings of PSVA. The clinical significance of MVD is unclear. Dogs with MVD were clinically normal when evaluated but long-term follow-up is not yet available. Dogs with hepatoportal MVD should be identified at an early age to avoid confusion in future diagnostic evaluations.

Neurological manifestation of cholesterinic granulomas in three horses.

Cholesterinic granulomas have been previously reported as an incidental post mortem in horses. Three adult horses with diencephalic dysfunction due to cholesterinic granulomas are described. All the horses exhibited profound depression, somnolence and reluctance to move. One horse experienced generalised seizures. Cerebrosinal fluid was xanthochromic with an elevated total protein in two of the cases evaluated. The large cholesterinic granulomas caused expansion of the lateral ventricle and secondary hydrocephalus due to the build up of cerebrospinal fluid behind the mass. Cholesterinic granulomas are believed to result from choroid plexus congestion and haemorrhage.

Ataxia due to a vertebral haemangiosarcoma in a horse.

A haemangiosarcoma in a horse resulted in ataxia affecting all four legs, a low head carriage and a reluctance to flex the neck. Ancillary diagnostic procedures included the analysis of cerebrospinal fluid, standing lateral cervical radiographs and a myelogram. Post mortem a tumour was found which involved the body of the second cervical vertebra and the associated hypaxial muscles, with secondary intravertebral extradural infiltration and focal compressive myelopathy. A histological examination showed that the tumour was a haemangiosarcoma.