MAGNETIC RESONANCE IMAGING OF INTRACRANIAL INFLAMMATORY CONDITIONS IN DOGS: SENSITIVITY OF SUBTRACTION IMAGES VERSUS PRE‐ AND POST‐GADOLINIUM T1‐WEIGHTED IMAGE PAIRS

Ante mortem diagnosis of canine meningoencephalitis is usually based on the results of neurologic examination, cerebrospinal fluid analysis and magnetic resonance (MR) imaging. It has been hypothesized that subtraction MR imaging may increase the sensitivity of MR for intracranial inflammatory lesions compared to conventional post‐gadolinium T1‐weighted imaging. Sensitivity of pre‐ and post‐gadolinium (C‐/C+) image pairs and dynamic subtraction (DS) images was compared in a retrospective diagnostic accuracy study of 52 dogs with inflammatory cerebrospinal fluid and 67 dogs with idiopathic epilepsy. Series of transverse C‐/C+ and DS images were reviewed independently for signs of abnormal enhancement affecting the pachymeninges, leptomeninges or intra‐axial structures. Sensitivity of C‐/C+ image pairs and DS images was 48% (95% CI: 35–61%) and 65% (95% CI: 52–77%), respectively (P = 0.01). Intra‐axial lesions were observed more frequently than meningeal lesions in both C‐/C+ (43% vs. 31%) and DS images (61% vs. 22%). The difference in sensitivities of C‐/C+ and DS series was entirely due to increased sensitivity of DS images for intra‐axial lesions. Eight (12%) dogs with epilepsy had evidence of intra‐axial gadolinium accumulation affecting the cerebral cortex in DS images. This finding may represent a false‐positive result or a true sign of pathology, possibly associated with a leaky blood–brain barrier in areas of the brain affected by neovascularization secondary to repeated seizures. Results suggest that DS imaging has higher sensitivity than comparison of pre‐ and post‐gadolinium image pairs for inflammatory intra‐axial lesions.     

Magnetic resonance imaging enhancement of intervertebral disc disease in 30 dogs following chemical fat saturation

Objective : To describe the patterns of enhancement of extradural intervertebral disc on chemically fat saturated gadolinium‐enhanced magnetic resonance images and to investigate the clinical and pathological associations with enhancement. Methods : Medical records and magnetic resonance images were reviewed from 30 dogs with histopathologically confirmed disc disease and enhancement on a T1‐weighted postcontrast fat saturated sequence. Results : Median duration of neurological signs was 4 days and the most common grade of severity was II, seen in 46·6% of dogs. Homogeneous, heterogeneous and peripheral patterns of disc enhancement were described, with peripheral enhancement most commonly identified (57% of dogs). There were no clinical or pathological differences between the dogs with each of the patterns. The mean signal intensity of a region of interest within the extruded disc material and contrast‐to‐noise ratio of the disc material were significantly higher on postcontrast T1‐weighted fat saturated images (P=<0·0001 each). Clinical Significance : The use of fat saturated gadolinium‐enhanced magnetic resonance imaging can detect enhancement of extradural disc material. Patterns of enhancement are not associated with the clinical presentation or pathological features.     

COMPARISON BETWEEN NONCONTRAST COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING FOR DETECTION AND CHARACTERIZATION OF THORACOLUMBAR MYELOPATHY CAUSED BY INTERVERTEBRAL DISK HERNIATION IN DOGS

Magnetic resonance imaging (MRI) and computed tomography (CT) are commonly used to evaluate dogs with thoracolumbar myelopathy; however, relative diagnostic sensitivities for these two modalities have not been previously reported. The purpose of this prospective study was to compare diagnostic sensitivity and observer agreement for MRI and CT in a group of dogs with thoracolumbar myelopathy due to surgically confirmed intervertebral disk herniation (IVDH). All included dogs had magnetic resonance (MR) imaging followed by noncontrast CT using standardized protocols. Three experienced observers interpreted each imaging study independently without knowledge of clinical or surgical findings. The operating surgeon was aware of MR findings but not CT findings at the time surgical findings were recorded. Forty‐four dogs met the inclusion criteria. The sensitivity of CT was 88.6% (79.5%–94.2%) and of MR was 98.5% (95% confidence interval, 94.1%–99.7%) for diagnosis of intervertebral disk herniation. Specificity was not calculated, as all dogs had IVDH at surgery. Magnetic resonance imaging was more accurate than CT for identifying the site of intervertebral disk herniation‐associated spinal cord compression and differentiating disk extrusion vs. protrusion. Computed tomography was less accurate for lesion localization in per acute cases, as well as for chondrodystrophic, female, older and smaller (<7 kg) dogs. Inter‐rater agreement was good for lesion lateralization for both MR and CT (κ = 0.687, 95% CI = 0.552, 0.822, P = 0.002, and κ = 0.692, 95% CI = 0.542, 0.842, P = 0.003). Findings from the current study indicated that MR imaging was more sensitive and accurate than noncontrast CT for diagnosis and characterization of thoracolumbar myelopathy due to IVDH in dogs.     

Incidence and type of brain herniation associated with intracranial meningioma in dogs and cats

The incidence of brain herniation (BH) in association with intracranial meningioma (ICM) in dogs and cats is poorly described. The aim of this study was to evaluate the rate and type of brain herniations in client-owned dogs and cats with ICMs and to determine the meningioma volume (MV) relative to cranial cavity volume (CCV). A retrospective magnetic resonance imaging (MRI) analysis study of 24 cats and 45 dogs with ICMs was conducted to ascertain the presence and characteristics of BH. MV and CCV were measured and their ratio was calculated for each animal. Correlations of MV/CCV with independent variables were analyzed. BH was encountered in 24/24 cats (100%) and 30/45 dogs (66.7%) with ICMs. In cats, the most frequent presentation was foramenal herniation (FMH; 23/24, 95.8%), followed by caudotentorial (CTH; 21/24, 87.5%) and subfalcine (SH; 18/24, 75.0%) herniation. In dogs, the most frequent presentation was SH (28/45; 62.2%), followed by CTH (9/45; 20%) and FMH (2/45; 4.4%). Relative to dogs, cats with ICM had greater incidences of FMH (P<0.001) and CTH (P<0.001). Mean MV/CCV ratio was higher in cats (0.098) than in dogs (0.038; P<0.001). The most common clinical sign of ICM was altered behavior in cats (43%, P<0.01) and seizures in dogs (74.4%, P<0.001). In conclusion, cats were found to be more likely than dogs to present FMH and CTH, with a proportionally greater neoplasia volume.     

Influence of signalment on developing cranial cruciate rupture in dogs in the UK

Objectives : To investigate risk factors associated with cranial cruciate ligament rupture in dogs. Methods : Retrospective case‐control study: medical records of a first‐opinion veterinary practice were searched for dogs diagnosed with cranial cruciate ligament rupture (1995 to 2007). For each case, six unaffected dogs were randomly selected from all dogs presenting that day for comparison. Multi‐variable binary logistic regression was performed to assess the association of variables on likelihood of cruciate rupture. Results : Frequency of cranial cruciate ligament rupture was 1·19% [95% confidence interval (CI) 1·02 to 1.36%]. West Highland white terriers (n=17), Yorkshire terriers (n=14) and Rottweilers (n=11) were at significantly increased risk of cranial cruciate ligament rupture (P≤0·002). Rottweilers were at five times greater risk compared with other pure breeds (OR 5·12, 95% CI 2·281 to 11·494, P<0·001), obesity quadrupled the risk of cranial cruciate ligament rupture (OR 3·756, 95% CI 1·659 to 8·502, P=0·001) and females were twice as likely to suffer cranial cruciate ligament failure compared to males (OR 2·054, 95% CI 1·467 to 2·877, P<0·001). Dogs less than two years old were statistically less likely to sustain cranial cruciate ligament rupture than dogs older than eight years (OR 0·246, 95% CI 0·127 to 0·477, P<0·001). There was no significant difference in median weights (in kilograms) of neutered dogs, compared to their entire counterparts in either the case group (P=0·994) or in the control group (P=0·630). There was also no significant difference in body condition (‐underweight/normal weight/overweight/obese) of neutered versus entire dogs among the cases (P=0·243), or the controls (P=0·211). Clinical Significance : Cranial cruciate ligament rupture is more likely in Rottweilers and in female dogs, older dogs and obese dogs. Following multi‐variable analysis, it was established that neutering was not associated with increased risk of cranial cruciate ligament rupture.     

Prevalence and clinical features of thoracolumbar intervertebral disc‐associated epidural hemorrhage in dogs

BackgroundIntervertebral disc‐associated epidural hemorrhage (EH) in dogs is a poorly understood neurological condition.ObjectiveTo compare the clinical presentation, magnetic resonance imaging (MRI) changes, and clinical outcome of dogs with acute thoracolumbar intervertebral disc herniation (TL‐IVDH) with and without EH.AnimalsOne hundred sixty client‐owned dogs that underwent MRI and hemilaminectomy for acute TL‐IVDH at a private practice in Colorado, including 63 dogs with EH and 97 dogs without EH.MethodsRetrospective review of medical record data from 160 dogs presenting sequentially to a single practice with acute TL‐IVDH that underwent MRI and hemilaminectomy surgery.ResultsSixty‐three of 160 (39%) dogs had confirmed EH. French Bulldogs were significantly overrepresented (23/63; odds ratio [OR]: 4.1; 95% confidence interval [CI]: 1.8‐9.0; P < .001) of the EH cases. Dogs with EH were more likely to present with clinical signs less than 48 hours than were dogs without EH (24‐48 vs 48‐72 hours; OR: 2.4; 95% CI: 1.2‐4.6; P = .02) and were more likely to be nonambulatory on presentation (OR: 2.1; 95% CI: 1.0‐4.1; P = .04). Dogs with EH were more likely to have <50% cross‐sectional spinal cord compression than dogs without EH (OR: 2.3 vs. 0.4; 95% CI: 1.2‐4.4 and 0.2‐0.9, respectively), longer longitudinal spinal cord compression (3 spaces vs 1 space, P < .001), and greater intrinsic spinal cord change (grade 3/severe vs grade 1/mild; P < .001) based on MRI. The location of the intervertebral disc herniation in French Bulldogs with EH was more likely to be thoracolumbar (OR: 10.8; 95% CI: 2.1‐55.7; P = .03).Conclusions and Clinical ImportanceFrench Bulldogs have a high prevalence of intervertebral disc‐associated EH. Dogs with EH have a shorter clinical course and are more likely to be nonambulatory on initial presentation.     

Prevalence of adverse food reactions in 130 dogs in Italy with dermatological signs: a retrospective study

Objectives : To determine the prevalence of adverse food reactions (AFRs) in dogs with dermatological signs presented to the referral dermatological clinic of the University of Milan. Methods : The medical records of dogs with dermatological signs were reviewed. Prevalence of AFRs was calculated. Owner and clinician pruritus scores were compared. Breed, sex and age predisposition were statistically tested, as was the association between AFR and selected clinical features. Results : The prevalence of AFRs in dogs with dermatological signs was 12% (16 of 130). AFR was diagnosed in 26% of dogs with allergic disease and 48% of those subjected to a dietary trial. There was a significant association between AFRs and early onset of clinical signs (<1 year) (OR=3·8; P=0·0221, 95% CI=1·27 to 11·16). There was a significant association between AFRs and both otitis externa (OR=5·9; P=0·0015, 95% CI=2 to 17·9) and perianal fistula (OR=26·1; P=0·0058, 95% CI=2·52 to 269·4), although all dogs with perianal fistulas were German shepherd dogs. Clinical Significance : The prevalence of AFRs in the study population was higher than most reported values. Further studies are warranted to investigate the true prevalence of AFR and its possible association with perianal fistula and other potential markers.     

Magnetic resonance imaging findings in Finnish Spitz dogs with focal epilepsy

Eleven Finnish Spitz dogs with focal seizures and 3 healthy controls were evaluated. General clinical and neurological examinations, blood examination, urinalysis, cerebrospinal fluid examination, electroencephalography (EEG), and magnetic resonance imaging (MRI) of the brain were performed on all dogs. On EEG examination, focal epileptic activity was found in 7 of 11 dogs (64%), and generalized epileptic activity was observed in 4 of 11 dogs (36%). MRI (performed with 1.5 T equipment) detected changes in 1 epileptic dog. Mild contrast enhancement after gadolinium injection was identified in this dog's right parietal cortex. However, no such changes were observed in repeated magnetic resonance images. Special emphasis was given to seizure history to determine any correlations between seizure intervals and MRI findings. Our results indicate that Finnish Spitz dogs with focal seizures suffer from focal idiopathic epilepsy and have nondetectable findings on MRI or pathology. MRI showed poor sensitivity in detecting epileptogenic areas in our patients with focal seizures. Reversible MRI changes in 1 dog could have been caused by seizures.     

Gadolinium contrast medium administration does not adversely affect T2*‐weighted gradient recalled echo magnetic resonance imaging of the canine brain at 1.5 Tesla

As gadolinium‐based contrast agents are paramagnetic and have T2 shortening effects, they have the potential to adversely affect gradient recalled echo sequences. The aim of this prospective, cross‐sectional study was to evaluate the effects of gadolinium administration on T2*‐weighted sequence diagnostic quality and signal intensity when imaging the canine brain. A total of 100 dogs underwent brain magnetic resonance imaging (MRI) including pre‐ and postcontrast T2*‐weighted sequences acquired with a delay (Group A) or immediately (Group B) following gadolinium administration. Pre‐ and postcontrast images were subjectively compared. In dogs with intracranial enhancing masses, regions of interest were drawn on corresponding images and signal intensity ratios were calculated. The effect of degree and pattern of contrast enhancement, susceptibility artifacts, and time between contrast injection and T2*‐weighted sequence acquisition on signal intensity ratio was evaluated. Overall 31 dogs had contrast enhancing intracranial masses. Subjectively, there was no difference in image quality of T2*‐weighted sequences obtained before and after contrast medium administration. No significant signal intensity differences of intracranial contrast enhancing masses were found (Group A P = 0.9999; Group B P = 0.9992). Susceptibility artifacts did not differ in appearance, and there was no effect on calculated signal intensity ratio (P = 0.8142). Similarly, there was no effect of degree of enhancement or contrast heterogeneity on signal intensity ratio (P = 0.4413). No correlation was found between signal intensity ratio and the time to acquisition (P = 0.199). Administration of gadolinium‐based MRI contrast agents does not adversely affect T2*‐weighted imaging of the brain in dogs at 1.5 T even in the presence of contrast enhancing lesions.     

Effect of acquisition time and chemical fat suppression on meningeal enhancement on MR imaging in dogs

Our purpose was to characterize meningeal gadolinium enhancement on magnetic resonance (MR) imaging in dogs with inflammatory and neoplastic diseases, and to assess interobserver variability and the impact of delayed acquisition and chemical fat saturation on its conspicuity. Transverse T1-weighted FLAIR images were acquired prior to, and immediately following gadolinium injection (T0), and at 5 (T5) and 15-20 min delay (TD), with and without fat suppression, in 155 consecutive dogs imaged for suspected brain disease. The agreement on meningeal enhancement was globally substantial (kappa = 0.61) and the likelihood of obtaining a definite diagnosis was significantly increased with the use of fat suppression (P < or = 0.004). Meningeal enhancement was judged definitively present by consensus in 46 of 155 (30%) dogs. Of these, meningeal enhancement was characterized qualitatively and quantitatively in 30 dogs with a clinical diagnosis (18 inflammatory, 11 neoplastic, 1 infarct), and image sequences were compared. Meningeal enhancement was more often diffuse and leptomeningeal in animals with inflammation versus neoplasia (50% vs. 42%, and 69% vs. 48%, respectively), but significant associations were not found. Meningeal thickness and contrast ratio were higher with neoplasia (P < or = 0.02), but results did not vary significantly between series for either group. Yet, images with fat suppression were most useful 50% of the time for definite diagnosis and/or characterization of meningeal enhancement. While delayed image acquisition following gadolinium injection does not improve characterization of meningeal enhancement in dogs, fat suppression is beneficial qualitatively.     

THORACOLUMBAR INTRADURAL DISC HERNIATION IN EIGHT DOGS: CLINICAL,LOW‐FIELD MAGNETIC RESONANCE IMAGING,AND COMPUTED TOMOGRAPHIC MYELOGRAPHY FINDINGS

Intradural disc herniation is a rarely reported cause of neurologic deficits in dogs and few published studies have described comparative imaging characteristics. The purpose of this retrospective cross sectional study was to describe clinical and imaging findings in a group of dogs with confirmed thoracolumbar intradural disc herniation. Included dogs were referred to one of four clinics, had acute mono/paraparesis or paraplegia, had low field magnetic resonance imaging (MRI) and/or computed tomographic myelography, and were diagnosed with thoracolumbar intradural disc herniation during surgery. Eight dogs met inclusion criteria. The prevalence of thoracolumbar intradural disc herniation amongst the total population of dogs that developed a thoracolumbar intervertebral disc herniation and that were treated with a surgical procedure was 0.5%. Five dogs were examined using low‐field MRI. Lesions that were suspected to be intervertebral disc herniations were observed; however, there were no specific findings indicating that the nucleus pulposus had penetrated into the subarachnoid space or into the spinal cord parenchyma. Thus, the dogs were misdiagnosed as having a conventional intervertebral disc herniation. An intradural extramedullary disc herniation (three cases) or intramedullary disc herniation (two cases) was confirmed during surgery. By using computed tomographic myelography (CTM) for the remaining three dogs, an intradural extramedullary mass surrounded by an accumulation of contrast medium was observed and confirmed during surgery. Findings from this small sample of eight dogs indicated that CTM may be more sensitive for diagnosing canine thoracolumbar intradural disc herniation than low‐field MRI.     

Cardiovascular effects of intravenous gadolinium administration to anaesthetized dogs undergoing magnetic resonance imaging

Objective To assess changes in heart rate and arterial blood pressure following intravenous (IV) gadolinium‐based contrast media administration to sevoflurane‐anaesthetized dogs undergoing magnetic resonance imaging (MRI). Study design Prospective clinical study. Animals Fifty client‐owned dogs (31 male, 19 female; aged 6–156 months; weighing 4.2–45.4 kg; ASA 2–3). Methods Heart rate and oscillometric blood pressures (systolic, mean and diastolic) were recorded at 10 minutes, 5 minutes and immediately pre‐administration of IV gadolinium contrast medium (time 0), then at 1, 2, 3, 5 and 10 minutes post‐gadolinium administration. Repeated measures anova was used to compare cardiovascular variables pre and post‐gadolinium administration. Significance was set at p < 0.05. Results There were no significant changes in cardiovascular variables following the IV administration of gadolinium. Conclusions and clinical relevance Administration IV of gadolinium‐based contrast media was not associated with adverse cardiovascular effects in these sevoflurane‐anaesthetized dogs undergoing MRI.     

The odds of neoplasia in dogs with and without diabetes mellitus

BackgroundIncreased risk of neoplasia in humans with diabetes mellitus (DM) is well documented. It is unknown if dogs with DM have increased risk of neoplasia.ObjectiveDetermine if dogs with DM have an overall increased risk of neoplasia and risk for specific forms of neoplasia compared to dogs without DM.AnimalsSeven hundred dogs with DM and 700 breed, age, and sex‐matched dogs without DM, examined during the same years.MethodsRetrospective case‐control study. Odds ratios (OR), corresponding 95% confidence intervals (CI), and P‐values were calculated using conditional logistic regression to determine if dogs with DM had increased odds of developing neoplasia compared to dogs without DM.ResultsThe overall odds of developing neoplasia were not significantly different in dogs with and without DM. However, dogs with DM had significantly higher odds of developing an adrenal mass (OR, 4; 95% CI, 1.1‐14.2; P = .03) compared to dogs without DM. The odds of developing a splenic mass in dogs with DM (OR, 1.2; 95% CI, 0.99‐1.39) were increased compared to dogs without DM, but this difference was not significant (P = .07).Conclusions and Clinical ImportanceDogs with DM may be at increased risk for adrenal neoplasia. Awareness of this risk can facilitate early diagnosis of this life‐threatening comorbidity. Larger studies are needed to confirm these findings.     

Clinical and imaging findings,treatments, and outcomes in 27 dogs with imaging diagnosed trigeminal nerve sheath tumors: A multi‐center study

The clinical behavior of canine trigeminal nerve sheath tumors and benefits of previously reported treatments are incompletely defined. Aims of this retrospective, multicenter, observational study were to describe clinical signs, tumor localization characteristics, treatments, and clinical outcomes in a group of dogs with this neoplasm. Databases at four hospitals were reviewed for dogs with a trigeminal nerve sheath tumor diagnosis, magnetic resonance imaging (MRI) studies, and presentation between 2004 and 2014. A single observer recorded medical record findings and two observers recorded MRI characteristics by consensus. A total of 27 dogs met inclusion criteria (15 treated with stereotactic radiation therapy and 12 unirradiated). Two unirradiated dogs were excluded from outcome analyses. The most common presenting signs were masticatory muscle atrophy (26 dogs), neurologic signs referable to intracranial disease (13), and ocular disease (12). Based on MRI findings, all dogs had disease extending centrally at the level of the brainstem. The most commonly affected trigeminal nerve branches were the mandibular (26 dogs), maxillary (22), and ophthalmic (10). Of 15 dogs treated with stereotactic radiation therapy, one had improved muscle atrophy, and six had poor ocular health after treatment. Neurologic signs improved in 4/5 dogs with intracranial signs. Overall median survival time for the 10 unirradiated dogs with available follow‐up was 12 days and 441 days for the 15 stereotactic radiation therapy dogs. Mean survival times between these groups were not significantly different (mean 95% CI for unirradiated dogs was 44–424 days and mean 95% CI for stereotactic radiation therapy dogs was 260–518 days).     

Chiari-like malformation and syringomyelia in normal cavalier King Charles spaniels: a multiple diagnostic imaging approach

Objectives : The objectives of the study were (1) to report the incidence of Chiari‐like malformation and syringomyelia in a normal French cavalier King Charles spaniel breeding population; (2) to precise the standard computed tomography dimensions of the caudal fossa and (3) to investigate the use of ultrasonography in diagnosis of this syndrome. Methods : Clinically normal adult cavalier King Charles spaniel underwent ultrasonographic examination of the spinal cord and caudal fossa. Computed tomography was used to measure the caudal fossa and magnetic resonance imaging allowed syringomyelia and cerebellar herniation identification. Results : Of the 16 dogs in the study, seven had syringomyelia (43·7 per cent). All dogs had cerebellar herniation, suggesting Chiari‐like malformation and also a tendency to occipital dysplasia. Computed tomography measurements of the caudal fossa are reported. In one dog, a syrinx was identified by ultrasonography. The only difference between dogs with or without syringomyelia was that dogs with Chiari‐like malformation/syringomyelia were statistically older. Clinical Significance : The incidence of Chiari‐like malformation and syringomyelia may be high in an asymptomatic population of cavalier King Charles spaniel . Computed tomography measurements reported in this study should now be compared with those of a symptomatic population to evaluate the hypothesis that dogs with Chiari‐like malformation/syringomyelia syndrome have a smaller caudal fossa. This study did not identify a smaller caudal fossa in an asymptomatic cavalier King Charles spaniel population with syringomyelia. Ultrasonography probably has a low sensitivity for diagnosis of Chiari‐like malformation/syringomyelia.     

MAGNETIC RESONANCE IMAGING FEATURES OF INTRAVENTRICULAR EPENDYMOMAS IN Five CATS

Intraventricular ependymoma is a rare type of feline intracranial neoplasia and published information on magnetic resonance imaging (MRI) characteristics is currently lacking. The purpose of this retrospective case series study was to describe the clinical and MRI characteristics of histopathologically confirmed intraventricular ependymomas in a group of cats. Five cats met inclusion criteria. In relation to normal gray matter, ependymomas appeared hyperintense on T2W, T2W‐FLAIR, PD, and DW‐EPI images; isointense on ADC images; and had subtle to strong contrast enhancement. Some variability was seen on T2*GRE and on T1W images with masses being isointense to hyperintense. Four ependymomas were small and homogeneous, and one was centrally cavitated. All cats had obstructive hydrocephalus, transtentorial herniation, and foramen magnum herniation. Perilesional edema was identified in most cats but was questionable in one. Intraventricular ependymoma should be considered as a differential diagnosis for cats with this combination of MRI signs.     

Risk factors for endoparasitism in dogs: retrospective case–control study of 6578 veterinary teaching hospital cases

Objectives : The diagnostic utility of routine faecal examinations can be greatly enhanced through an appreciation of risk factors most commonly associated with endoparasitism. Methods : From a sample of 6578 canine patients presenting to a veterinary teaching hospital between 1996 and 2006, this study used univariate and multi‐variable techniques to examine putative signalment, medical history and demographic factors predisposing dogs to intestinal parasites. Results : Age and median household income were the strongest predictors of endoparasitism. The odds of a patient being diagnosed with endoparasites were 0·82 times smaller for every 1 year increase in age (OR=0·82, 95% CI: 0·80 to 0·84) and for every $10,000 increase in median household income, the odds were 0·86 times lower (OR=0·86, 95% CI: 0·83 to 0·89). The variables gender, neuter status, month of diagnosis, admitting clinical service and primary diagnosis were not significant predictors. Animals that were presented for underlying medical conditions were less likely to have parasites and the presence of diarrhoea was associated with 76% lower odds of endoparasitism compared to healthy animals (OR=0·76, 95% CI: 0·64 to 0·90). Clinical Significance : Clinicians should maintain a high index of suspicion for parasites in younger patients that live in high population density and low income neighbourhoods.     

CONTRAST ENHANCEMENT OF EXTRADURAL COMPRESSIVE MATERIAL ON MAGNETIC RESONANCE IMAGING

Gadolinium‐enhancement of compressive extradural material is detected occasionally with magnetic resonance (MR) imaging in dogs. Our goal was to characterize contrast enhancement of extradural compressive material associated with intervertebral disc herniation, and to evaluate the association between enhancement and histopathologic findings and the onset of clinical signs. Ninety‐three dogs with a total of 99 lesions diagnosed as intervertebral disc herniation on MR imaging were assessed. Images were evaluated for lesion location, type of herniation, degree of compression, intramedullary T2‐weighted (T2W) intensities, and contrast enhancement. In 23 dogs, surgically removed compressive material was evaluated histopathologically for hemorrhage, inflammation, neovascularization, fibroplasia, fibrosis, mineralization, necrosis, and chronicity. Contrast enhancement of extradural compressive material, meninges, and both the compressive materials and meninges was present in 51.5%, 39.4%, and 17.2% of lesions, respectively. Extradural enhancement occurred more frequently in extrusions than protrusions (P=0.001). Meningeal enhancement and more severe neurologic deficits were significantly associated with a shorter duration of clinical signs (P=0.04 and 0.01, respectively). Intramedullary T2W hyperintensities, present with 44.4% of lesions, were associated with more severe neurologic deficits (P=0.001). Lesions with extradural enhancement were more often considered subacute to chronic in duration and more frequently associated with hemorrhage compared with nonenhancing material; however, no statistically significant association was established between contrast enhancement and histopathologic findings. Contrast enhancement of extradural compressive material and the meninges was found to be common with intervertebral disc herniation, and should not be interpreted as a specific sign of a mass lesion such as neoplasia.     

Gall bladder mucoceles and their association with endocrinopathies in dogs: a retrospective case‐control study

Objective : To investigate the relationship between endocrinopathies and diagnosis of gall bladder mucocele in dogs via a retrospective case‐control study. Methods : Records of 78 dogs with a surgical or ultrasonographic diagnosis of gall bladder mucocele were examined for the presence or absence of hyperadrenocorticism, hypothyroidism and diabetes mellitus. Two age‐ and breed‐matched controls for each gall bladder mucocele dog (156 total control dogs) were examined for the same concurrent diseases. A matched case‐control analysis was performed using conditional logistic regression. Results : The odds of mucocele in dogs with hyperadrenocorticism were 29 times that of dogs without hyperadrenocorticism (P=0·001; 95 per cent CI 3·8, 219·9). No difference was found between dogs with and without diabetes mellitus. Although a significant association was found between gall bladder mucocele and hypothyroidism, potential observation bias was also identifi ed. Clinical Significance : Hyperadrenocorticoid dogs that were presented for acute illness with laboratory evidence of hepatobiliary disease should undergo evaluation for the presence of a biliary mucocele. Dogs diagnosed with a gall bladder mucocele should be screened for concurrent hyperadrenocorticism if clinical suspicion exists.     

Prognostic significance of specific magnetic resonance imaging features in canine nasal tumours treated by radiotherapy

Objectives : To investigate the prognostic significance of the magnetic resonance (MR) findings of meningeal hyperintensity of the olfactory bulbs and tumour extension into the caudal nasal recess (CNR) in dogs with nasal tumours treated by radiotherapy. Methods : MR images of 41 dogs with nasal tumours treated with radiotherapy were reviewed. The occurrence of neurological signs and survival of patients with and without meningeal hyperintensity of the olfactory bulbs and tumour extension into the CNR were analysed together with possible confounding factors including intracranial extension and patient age. Results : There was no significant association between the presence of meningeal hyperintensity or CNR involvement and the occurrence of neurological signs. Although there was a tendency towards shorter survival in dogs with tumour extension into the CNR, multivariable analysis showed no significant difference in survival between dogs with/without CNR involvement, meningeal hyperintensity or intracranial tumour extension (P=0·12, 0·50 and 0·57, respectively). Clinical Significance : In dogs with nasal tumours treated with radiotherapy, tumour extension into the cranium is not necessarily associated with shorter survival in patients without neurological signs at time of diagnosis. Although a definite influence of CNR involvement on case outcome could not be demonstrated, studies with a larger population are warranted.