Diagnosis and long-term outcome in dogs with acute onset intracranial signs.

OBJECTIVES: To investigate dogs with acute onset of intracranial signs suspected of stroke by primary veterinary clinicians, and establish possible differential diagnoses and long-term outcome. In addition, serum C-reactive protein and plasma cytokines were investigated as potential biomarkers of disease. MATERIALS AND METHODS: All cases were evaluated by neurologic examination, routine haematology and biochemistry and measurement of serum C-reactive protein, plasma cytokine concentrations (interleukin-2, -6, -8, -10, tumour necrosis factor) and low-field MRI. RESULTS: Primary veterinarians contacted the investigators with 85 suspected stroke cases. Only 20 met the inclusion criteria. Of these, two were diagnosed with ischaemic stroke. Other causes were idiopathic vestibular syndrome (n=6), brain tumour (n=5) and inflammatory brain disease (n=2); in five cases a precise diagnosis could not be determined. Median survival times were: brain tumour, 3 days, idiopathic vestibular syndrome, 315 days, ischaemic stroke, 365 days and inflammatory central nervous system (CNS) disease, 468 days. The median plasma concentrations of interleukin-2, -6, -8, -10 or tumour necrosis factor were not significantly increased in any of the diagnosis groups compared to healthy controls. Serum C-reactive protein was higher in dogs with brain tumours and inflammatory brain disease but not above the upper bound of the reference interval. CLINICAL SIGNIFICANCE: Dogs that present with acute onset intracranial disease may have ischaemic stroke but are more likely to have other causes. Many dogs with such acute onset of neurological dysfunction (brain tumours excluded) may recover within a couple of weeks despite their initial severe clinical appearance.

Diagnosis of canine pulmonary thromboembolism by computed tomography and mathematical modelling using haemostatic and inflammatory variables.

There is no evidence-based diagnostic approach for diagnosis of pulmonary thromboembolism (PTE) in dogs. Many dogs with diseases that predispose to thrombosis are hypercoagulable when assessed with thromboelastography (TEG), but no direct link has been established. The aims of this study were: (1) to investigate if diseased dogs with PTE, diagnosed by computed tomography pulmonary angiography (CTPA), had evidence of hypercoagulability by TEG; (2) to characterise haemostatic and inflammatory changes in dogs with PTE; (3) to construct models for prediction of PTE based on combinations of haemostatic and inflammatory variables; and (4) to evaluate the performance of D-dimer measurement for prediction of PTE. Twenty-five dogs were included in this prospective observational study (PTE: n=6; non-PTE: n=19). Clot strength G values did not differ between the PTE and non-PTE groups in tissue factor (TF) or kaolin-activated TEG analyses. Haemostatic and inflammatory variables did not differ between the two groups. Linear discriminant analysis generated a model for prediction of PTE with a sensitivity and specificity of 100% when TF results were used as TEG data, and a model with sensitivity of 83% and specificity of 100% when kaolin results were used as TEG data. Receiver operating characteristic analysis of D-dimer levels showed that a value of >0.3mg/L yielded a sensitivity of 100% and a specificity of 71.4%. In conclusion, the study supports CTPA as method for diagnosing canine PTE, but shows that TEG alone cannot identify dogs with PTE. Models for prediction of PTE were generated, but require further validation.

Texture analysis of pulmonary parenchymateous changes related to pulmonary thromboembolism in dogs - a novel approach using quantitative methods.

BACKGROUND: Diagnosis of pulmonary thromboembolism (PTE) in dogs relies on computed tomography pulmonary angiography (CTPA), but detailed interpretation of CTPA images is demanding for the radiologist and only large vessels may be evaluated. New approaches for better detection of smaller thrombi include dual energy computed tomography (DECT) as well as computer assisted diagnosis (CAD) techniques. The purpose of this study was to investigate the performance of quantitative texture analysis for detecting dogs with PTE using grey-level co-occurrence matrices (GLCM) and multivariate statistical classification analyses. CT images from healthy (n = 6) and diseased (n = 29) dogs with and without PTE confirmed on CTPA were segmented so that only tissue with CT numbers between -1024 and -250 Houndsfield Units (HU) was preserved. GLCM analysis and subsequent multivariate classification analyses were performed on texture parameters extracted from these images. RESULTS: Leave-one-dog-out cross validation and receiver operator characteristic (ROC) showed that the models generated from the texture analysis were able to predict healthy dogs with optimal levels of performance. Partial Least Square Discriminant Analysis (PLS-DA) obtained a sensitivity of 94% and a specificity of 96%, while Support Vector Machines (SVM) yielded a sensitivity of 99% and a specificity of 100%. The models, however, performed worse in classifying the type of disease in the diseased dog group: In diseased dogs with PTE sensitivities were 30% (PLS-DA) and 38% (SVM), and specificities were 80% (PLS-DA) and 89% (SVM). In diseased dogs without PTE the sensitivities of the models were 59% (PLS-DA) and 79% (SVM) and specificities were 79% (PLS-DA) and 82% (SVM). CONCLUSION: The results indicate that texture analysis of CTPA images using GLCM is an effective tool for distinguishing healthy from abnormal lung. Furthermore the texture of pulmonary parenchyma in dogs with PTE is altered, when compared to the texture of pulmonary parenchyma of healthy dogs. The models' poorer performance in classifying dogs within the diseased group, may be related to the low number of dogs compared to texture variables, a lack of balanced number of dogs within each group or a real lack of difference in the texture features among the diseased dogs.

Bilateral oblique facial clefts, rudimentary eyes and hydrocephalus in an aborted equine foetus.

Knowledge of congenital malformations and their causes in horses is generally sparse. Such conditions require more scientific attention to improve their diagnostics and inform prevention strategies. Here, a unique syndrome of bilateral oblique facial clefts (meloschisis), rudimentary eyes and hydrocephalus is reported in an equine foetus spontaneously aborted at gestation day 224. The cause of abortion was considered to be intrauterine death caused by umbilical cord torsions and subsequent compromised blood flow, but the aetiology of the malformation could not be determined. A detailed history, which includes exposure to a range of pharmaceutical compounds during the early stages of pregnancy, is provided and emphasizes the need for accurate recording of treatments in pregnant animals.

Late gestation undernutrition can predispose for visceral adiposity by altering fat distribution patterns and increasing the preference for a high-fat diet in early postnatal life.

We have developed a sheep model to facilitate studies of the fetal programming effects of mismatched perinatal and postnatal nutrition. During the last trimester of gestation, twenty-one twin-bearing ewes were fed a normal diet fulfilling norms for energy and protein (NORM) or 50% of a normal diet (LOW). From day 3 postpartum to 6 months (around puberty) of age, one twin lamb was fed a conventional (CONV) diet and the other a high-carbohydrate-high-fat (HCHF) diet, resulting in four groups of offspring: NORM-CONV; NORMHCHF; LOW-CONV; LOW-HCHF. At 6 months of age, half of the lambs (all males and three females) were slaughtered for further examination and the other half (females only) were transferred to a moderate sheep diet until slaughtered at 24 months of age (adulthood). Maternal undernutrition during late gestation reduced the birth weight of LOW offspring (P<0·05), and its long-term effects were increased adrenal size in male lambs and adult females (P<0·05), increased neonatal appetite for fat-(P=0·004) rather than carbohydrate-rich feeds (P<0·001) and reduced deposition of subcutaneous fat in both sexes (P<0·05). Furthermore, LOW-HCHF female lambs had markedly higher visceral:subcutaneous fat ratios compared with the other groups (P<0·001). Postnatal overfeeding (HCHF) resulted in obesity (.30% fat in soft tissue) and widespread ectopic lipid deposition. In conclusion, our sheep model revealed strong pre- and postnatal impacts on growth, food preferences and fat deposition patterns. The present findings support a role for subcutaneous adipose tissue in the development of visceral adiposity, which in humans is known to precede the development of the metabolic syndrome in human adults.

Relationship between bone strength and dual-energy X-ray absorptiometry measurements in pigs.

Computed tomography and a 3-point bending test were performed on the metacarpal bones of adult production pigs to test the hypothesis that bone strength is strongly correlated with areal bone mineral density (BMD) in this population. The aim of the study was to subject material from adult production pigs grouped by BMD to 3-point bending, to test this hypothesis and determine any correlations. In all, 168 individual computed tomography scans and mechanical tests were performed on the collected material. For evaluation purposes, the material was divided into the categories low, medium, and high BMD (<1, 1 to 1.4, and >1.4 g/cm(2), respectively). The results showed a difference in the maximum load, in the stress at maximum load, and stiffness among each BMD group (P < 0.001) and in elastic modulus between the low BMD group and the 2 other groups (P < 0.001). A correlation between both intrinsic and extrinsic measures of bone strength and BMD was thus demonstrated. The projected change in each of the variables reported, for a 0.1 g/cm(2) alteration in BMD (within the BMD range evaluated in this study), is as follows: maximum load, 708 N; stress at maximum load, 50 N/mm(2); stiffness, 391.6 N/mm; and elastic modulus, 108 N/mm(2) (P < 0.001). The results confirm the relationship between BMD and bone strength and indicate that BMD screening can be used in fracture risk assessments in production pigs.

Dual-energy X-ray absorptiometry of the pig: Protocol development and evaluation.

As part of a prospective study in bone mineralisation in adult pigs it was necessary to establish guidelines and to define sites for bone mineral measurements. Particular requirements were that, the protocol should be suitable for a mass screening programme in both postmortem specimens and in live animals, and should deliver results of known reliability. Estimates of bone mineral content (BMC) and bone mineral density (BMD) in areas within the 4th metacarpal bone yielded coefficients of variation (CV) in the order of 7% for both regions and estimates in regions which included the entire metacarpal-phalangeal area yielded CV values in the order of 0.7% and 0.6% for BMC and BMD, respectively. A region of interest taken from the coccygeal vertebrae yielded coefficient of variation values of 3% and 2% for BMC and BMD, respectively. Accuracy of dual-energy X-ray absorptiometry (DXA) was estimated using a standard curve derived from BMC determined by ashing. There was a high correlation between mineral content determined by DXA and by ashing (R(2)=0.99, p<0.0001). The results suggest that the regions used in this study are suitable for use in large, mass screening, prospective studies.

Accuracy of diagnostic ultrasound for detection of cystic lesions: determination using receiver operating characteristic curve analysis of findings in phantom studies.

Anechoic, spherical cystic lesions are important findings on ultrasound examination. In polycystic renal disease of cats, they may be the only ultrasonographic sign of disease. This study assesses the accuracy of ultrasound, as used in a veterinary setting, for the detection of cysts. Using a spherical lesion ultrasound imaging phantom and 7.5- to 8-MHz linear array transducers, images of cysts of 2- and 4-mm diameter were created at various imaging depths from 0 to 6 cm. These were digitized and given to a panel of readers for interpretation. Area under receiver operating characteristic curves were used to evaluate test accuracy. It was shown that test accuracy was different at different imaging depths and differed with machines of differing price category. It is suggested that when setting standards for quality control in ultrasound, criteria used might be better related to imaging outcome studies rather than to aspects of machine specification.

Ovarian cysts in guinea pigs: influence of age and reproductive status on prevalence and size.

Forty-three guinea pigs presented as part of a screening programme were divided into six categories on the basis of age and reproductive history. Three age groupings were used: less than one year, one to two years, and over two years. Each age group was further divided into two categories: animals which had had single or multiple pregnancies, and animals which had never bred. Each animal received a clinical examination and was scanned using B-mode ultrasound for the presence of ovarian cysts. Possible relationships between reproductive history and the prevalence of cysts were investigated using Mantel-Haenzel analysis, and between prevalence, cyst size and age using linear regression analysis. Two out of the 43 animals (4.7 per cent) showed symmetrical alopecia. No statistically significant correlation between reproductive history and the prevalence of cysts was detected at the 95 per cent confidence level. A statistically significant relationship was found, however, between cyst size and age (P<0.01) and between cyst prevalence and age (P<0.02).

An experimental clot model in sheep; generation of a heterologous clot and its detection in vivo using venography and (125)I labelled fibrinogen.

An experimental venous clot model using the lateral saphenous vein of sheep is described. Eight experimental Suffolk crossbred sheep were used. A mixture of human fibrinogen, in some cases labelled with (125)I, bovine thrombin and homologous whole blood was placed via a catheter into a surgically isolated segment of the lateral saphenous vein. The resulting heterologous clot was imaged daily for 6 days using venography, or monitored using an external gamma ray detector. Clots were radiographically detectable for the 6 days of the study. They were totally occlusive for a mean of 4.2 days (SD 2.2) and were occlusive in the immediate 24 hour period after surgery. The fibrin component of the clot was persistent (85 per cent of the initial fibrin[ogen] present after 6 days). Radiographically the clots were seen as filling defects within partially filled vessels, or their presence was inferred from the absence of filling. A collateral blood supply was apparent immediately on vessel occlusion. No adverse effects, evidence of infection or limb oedema were seen. The model provided a reproducible blood clot within the lateral saphenous vein of the sheep. Clot imaging using venography was effective and readily achieved. It is suggested that the model is useful when a stable, intravenous deposit of heterologous (e.g. human) fibrin is required in vivo at a site suitable for venography and radionucleid monitoring.

In vivo penetration of experimentally produced clots by monoclonal antibodies.

Antifibrin monoclonal antibodies show potential as clot targeting agents for diagnosis and possibly therapy in thrombotic disease. To be effective the antibody must bind to the fibrin component of the clot. The ability of two antifibrin mabs (NIB 1H10 and NIB 12B3) to penetrate occlusive clots in vivo was investigated. Both mabs react with human fibrin but not with human fibrinogen nor with the fibrin or fibrinogen from the species used in this study. Two heterologous animal (sheep and rabbit) thrombus models were used. Clots in both cases were made within isolated vein segments using a mixture of human and native fibrinogen. The clots in sheep veins were observed radiographically and found to be occlusive for a mean of 4.2 +/- 2.2 days and thereafter appeared only partially occlusive. When targeted in their occlusive phase (131)I labelled mab accumulated in the clot reaching a maximum ratio of 1.82 +/- 0.42 when compared to counts in homologous sheep clots in the contralateral limb. It was confirmed in the rabbit jugular vein model that total occlusivity did not prevent antibody accumulation in the heterologous clot by injecting the fibrin specific mab 1H10 and examining the clot excised after 1, 6 and 24 h using immunofluorescence. In a further series of similar experiments (125)I labelled mab 1H10 was used and detected using autoradiography. Both sets of experiments indicated that penetration of occlusive clots by the antibody occurred and that considerable accumulation was present at 6 and 24 h. The results indicate that a circulating antibody can readily gain access to experimentally produced clots in occluded veins.

Detection of portal blood flow using per-rectal 99mTc-pertechnetate scintigraphy in normal cats.

This study reports data obtained from per-rectal 99mTc-pertechnetate portal scintigraphy in normal cats. It examines the effects of chemical restraint and the methods employed in defining regions of interest (ROIs) on the shunt index derived from this data. Six normal cats were used for the study; all six were chemically restrained for imaging using propofol and later four of them were manually restrained for comparison. Portal blood flow was studied and the mean shunt index was found to be 5.9% +/- 3.9 when ROIs were operator defined and 9.2% +/- 4.4 when ROIs were defined using an isocontour program. In cats that were restrained using propofol and operator defined ROIs, the mean value for the time between detection of radioactivity in the liver and in the heart was 14 +/- 1 seconds.

Surgical treatment of intrahepatic portosystemic shunts in 45 dogs.

The surgical attenuation of an intrahepatic portosystemic shunt in 45 dogs is described. Twenty-nine (64 per cent) had left divisional shunts consistent with a patent ductus venosus (PDV), 15 (33 per cent) had central divisional shunts and one had a right divisional shunt. In the dogs with a PDV, the shunt vessel could be most easily manipulated at a posthepatic site, whereas in those with central and right divisional shunts the manipulation could be more easily made intrahepatically but sometimes involved demanding intravascular surgical techniques. Eight dogs (18 per cent) died during the surgery or shortly afterwards. Of the 37 dogs surviving longer term, 28 (76 per cent) became clinically normal and required no medication or diet control. In a further three animals the shunt was ligated completely only during a second surgical procedure. The remaining six dogs were euthanased because of clinical signs of encephalopathy which were either surgically or medically uncontrollable.

Percutaneous balloon pericardiotomy for the management of malignant pericardial effusion in two dogs.

Two dogs with signs of right-sided congestive cardiac failure, due to recurrent pericardial effusion secondary to the presence of intrapericardial neoplasia, were treated by percutaneous balloon pericardiotomy. The first patient was euthanased one month after the procedure while the second patient developed ascites as a result of obstruction of the caudal vena cava by the growing tumour and was euthanased 14 weeks after the procedure. In neither case was there a recurrence of a significant volume of the effusion. Percutaneous balloon pericardiotomy represents an effective means of relieving recurrent malignant pericardial effusion, without resorting to thoracotomy.

A method for controlling portal pressure after attenuation of intrahepatic portacaval shunts.

Two dogs had right divisional intrahepatic portacaval shunts within the right lateral lobe of the liver. In both dogs, an extrahepatic portacaval vascular anastomosis was created, using an autologous right external jugular vein graft. The intrahepatic shunts were completely attenuated using a prehepatic intravascular caval approach. The creation of the vascular graft allowed postattenuation rises in portal pressure to be controlled, preventing the development of life threatening portal hypertension. Both dogs recovered from the procedure. One dog is clinically normal and does not require medication (8 months postoperatively); the other dog was euthanatized 5 months after surgery because of renal failure. Scintigraphy studies, performed before surgery, showed significant shunting of portal blood away from the liver (shunt indices 65% and 59%), whereas, similar studies done 4 weeks afterwards showed almost normal portal blood flow (shunt indices 16% and 18%, respectively).

Ultrasonographic diagnosis of congenital portosystemic shunt in 14 cats.

Twenty-four cats with clinical and, or, clinicopathological signs compatible with portosystemic shunting were examined prospectively using two-dimensional grey-scale, duplex and colour-flow Doppler ultrasonography. Diagnosis of congenital portosystemic shunt was subsequently confirmed in 14 cats using operative mesenteric portography and surgery. Of the 14 affected cats, nine were purebred; eight were male and six female. The mean age at the time of diagnosis was nine months (range four to 27 months). Ultrasonographic evidence of a small liver was present in seven cats (50 per cent); visibility of intrahepatic portal vessels was reduced in three (21 per cent). An anomalous blood vessel was identified ultrasonographically in each cat; in 10 cats (71 per cent) the vessel was observed to originate from the portal vein and drain into the caudal vena cava. Abnormally variable portal blood flow was present in eight of the 10 cats in which it was measured. At surgery, six shunts were intrahepatic and eight extrahepatic; the ultrasonographic diagnosis of intra- versus extrahepatic shunt was correct in 13 cats (93 per cent). No anomalous blood vessels or abnormalities affecting the portal vein were detected ultrasonographically in any of the 10 cats that did not have congenital portosystemic shunting. Hence, the accuracy of ultrasonography for diagnosis of congenital portosystemic shunting in this series was 100 per cent.

Detection of fibrin in canine neoplasia.

A murine monoclonal antibody, designated 1H10, produced using a human fibrin-related immunogen, was shown to bind avidly to dog fibrin, but not to dog fibrinogen. Using immunofluorescence, fibrin was detected in canine gastric adenocarcinoma and in mixed tissue from a mammary tumour. No fibrin could be detected in bronchogenic carcinoma tissue.

Per rectal portal scintigraphy in the diagnosis and management of feline congenital portosystemic shunts.

Five cats with a congenital portosystemic shunt (CPSS) were examined using transcolonic portal scintigraphy before and after surgical ligation of the shunting vessel. The mean shunt index before surgery was 52 per cent (range 45 to 61 per cent). Repeat portal scintigraphy, six to eight weeks after surgery, indicated a significant reduction in shunt index (mean 13 per cent, range 5 to 25 per cent) in four cats. In one of these cats a marked reduction in the shunt index, as determined by scintigraphy, preceded normal fasting blood ammonia. In the fifth cat there was no significant change in the shunt index, fasting serum bile acids and blood ammonia six months after surgery, although its clinical signs of hepatic encephalopathy had improved. Portal scintigraphy is useful in the diagnosis of CPSS and enables a quantitative assessment of the effects of surgery and may be a more accurate indicator of the degree of shunting after surgery than blood ammonia and serum bile acids.