The effect of midline shift on survival time in dogs with structural brain disease diagnosed on MRI.

The effect of midline shift identified on brain MRI on survival time in dogs with structural brain disease is relatively unknown. This retrospective single-centered cohort study reviewed medical and imaging data of 77 dogs with structural brain lesions evident on MRI. Images were reviewed for the presence of midline shift, brain edema, foramen magnum herniation, and ventriculomegaly. Kaplan-Meier method and Cox regression analysis were undertaken to compare survival between dogs with and without midline shift. Midline shift was present in 40 of 77 (52%) dogs and absent in 37 of 77 (48%). Univariate analysis revealed that dogs with midline shift had a median survival time of 34.5 days (95% CI, 4-108 days) compared with 241 days (95% CI, 133,- days) in dogs without midline shift (hazard ratio = 2.67, 95% CI, 1.5-4.49). Multivariate Cox regression analysis revealed a hazard ratio of 3.6 (95% CI, 1.7-7.6; P-value < .001) for dogs with midline shift. Shorter median survival times remained significant in all groups after segregation based on etiological diagnosis. The significantly shorter survival times observed herein for dogs with midline shifts, regardless of etiologic cause, provide further evidence that midline shift holds value as a negative prognostic factor in diagnostic imaging.

Use of underwater contactless ultrasonography to elucidate the internal anatomy and reproductive activity of manta and devil rays (family: Mobulidae).

The ability to visualise the internal anatomical structures of fish provides important information on their reproductive status and body condition and has made important contributions to many areas of fish biology. Obtaining information on the internal anatomy of fish has traditionally required euthanasia and dissection. Although ultrasonography is now increasingly used to study internal fish anatomy without the need for euthanasia, traditional techniques still require restraint and contact with the animal, both of which are known to cause stress. This has prompted the development of waterproof, contactless and portable equipment to allow ultrasonographic examinations to be carried out in free-swimming individuals, which also facilitates the application of this tool in wild populations of endangered species. This study reports the validation of this equipment using anatomical examinations of nine manta and devil ray (Mobulidae) specimens landed at fish markets in Sri Lanka. The species studied were Mobula kuhlii (n = 3), Mobula thurstoni (n = 1), Mobula mobular (n = 1), Mobula tarapacana (n = 1) and Mobula birostris (n = 3). The use of this equipment was further validated with ultrasonographic examinations in 55 free-swimming reef manta rays Mobula alfredi, which enabled maturity status to be quantified in 32 females. Structures successfully identified in free-swimming individuals were the liver, spleen, gallbladder, gastrointestinal tract, skeletal structures, developing follicles and uterus. The study demonstrated that ultrasonography provided a reliable method of determining both sexual maturity and gestational status in free-swimming M. alfredi. The methodology induced no detectable signs of disturbance to the animals involved and therefore offers a viable and practical alternative to invasive techniques currently used to study anatomical changes in both captive and wild marine organisms.

Follow-up MRI appearance of the surgical site in dogs treated for thoracolumbar intervertebral disc herniation and showing ongoing or recurrent neurological symptoms.

Reherniation and reoperation rates of 4.5%-36% are reported in canine patients treated for intervertebral disc herniation (IVDH). Decision-making for surgical reintervention can prove challenging, especially since common postoperative changes are poorly described on MRI. The purpose of this single-center, retrospective, descriptive study was to describe the MRI characteristics of the surgical site in dogs treated for thoracolumbar IVDH and presenting for ongoing or recurrent neurological signs. Twenty-one patients were included for a total of 42 MRI studies. Chondrodystrophic breeds, specifically Dachshunds, were overrepresented. Mean number of days between surgery and second MRI was 335 (range 2-1367). Metallic susceptibility artifacts were seen in seven of 21 cases (33%), but these were limited in extent, spanning on average 1.3 vertebral bodies. In 11 cases, spinal cord compression suspected to be clinically significant was found at the surgical site; the extradural compressive material consisted of intervertebral disc material only, or a combination of intervertebral disc material and hematoma or inflammatory changes in 10 cases, and a displaced articular process and fibrous tissue in one case. The latter is a newly described complication of mini-hemilaminectomies. Paravertebral soft tissue changes and vertebral new bone formation varied according to the postoperative stage at which the patients were imaged. The results of this study supported the use of MRI as a diagnostic modality for spinal imaging following IVDH surgery, and showed that the presence of extradural disc material at a spinal surgical site is common along with various vertebral and paravertebral changes.

Prevalence of incidental humeral intracondylar fissures in brachycephalic breed dogs in CT studies.

Humeral intracondylar fissures (HIF) have been predominantly reported in spaniel breeds and proposed to be possible risk factors for humeral condyle fractures (HCF). We hypothesized that the prevalence of incidental HIF in French Bulldogs may be greater than that of other brachycephalic breeds. A retrospective, observational, prevalence study was performed using CT examinations of French bulldogs and other brachycephalic breed dogs presenting for an unrelated condition. Two European College of Veterinary Diagnostic and Imaging-certified radiologists reviewed the images of the humeral condyles of these dogs. A classification system was devised to grade the findings. We considered a Score 1 to be normal, Score 2 to have centralised sclerosis, Score 3 to have a partial fissure and Score 4 to have a complete fissure. A total of 228 elbows were reviewed from 122 dogs. Of this population, 145 elbows were from French Bulldogs, 54 were from Pugs, and the remainder were from a mix of other brachycephalic breeds. The prevalence of HIF (score 3 or 4) in elbows of the French bulldog, pug and other breed groups was 6.9% (CI 2.8-11%), 5.6% (CI 0-11.7%), and 3.4% (CI 0-10.15%), respectively. At a dog level, the prevalence of HIF (score 3 or 4 present in at least one elbow) was found to be 11.8% (CI 4.6-19%) in French Bulldogs, 11.1% (CI 0-22.9%) in Pugs, and 5.26% (CI 0-15%) in the other breed group. There was no significant difference between the breed groups. The inter-reviewer reliability for CT scoring of HIF based on Cohen's weighted kappa was low at 0.19.

Prevalence and clinical correlations of olfactory recess dilatation in MRI studies of the feline brain.

The ability to differentiate clinical ventriculomegaly from incidental ventricular enlargement remains a challenge in veterinary radiology. Dilatation of one or both olfactory lobe recesses is occasionally seen on MRI of the brain in otherwise normal cats. The purpose of this study was therefore to determine the prevalence of this finding within a population of neurologically normal and neurologically abnormal cats, and to investigate associations with signalment, clinical and neurological examination findings, and MRI features. An observational retrospective cohort study was performed, and archived records were searched for cats that had undergone MRI of the head, including the olfactory lobes. Medical data and MRI parameters were recorded. One hundred fifty-one cats were included, with olfactory recess dilatation present in 56 cats. In 16 neurologically normal cats, olfactory recess dilatation was the only MRI finding. Olfactory recess dilatation was not associated with age, sex, breed, or with the presence of nasal disease. A significant association was found between generalized ventriculomegaly (P = 0.001) and the presence of CSF abnormalities (P = 0.036). Eleven percent of our cohort (16/151) demonstrated olfactory recess dilatation in the absence of other neurological or structural intracranial disease, suggesting that this may be seen as a normal variation in some cats.

Natural ballistic gelatine ultrasound phantoms are suitable to be used for student education and can be produced cheaply and effectively.

Practical experience in ultrasonography at medical and veterinary schools is difficult to achieve using live models due to ethical considerations. A solution to this problem has been the creation of synthetic ultrasound phantoms that allow simulation of both ultrasound scans and ultrasound-guided procedures. Whilst commercially available phantoms are expensive in a resource-limited environment, it would be desirable to create affordable, reusable, homemade phantoms which could be used to aid student learning. Recent studies have indicated that ballistic gelatine is an excellent material for this. A prospective, experimental study was performed with three ultrasound phantoms for student use. Vascular, bladder, and liver parenchymal models were produced with a natural ballistic gel, along with instructions for their construction and maintenance. Model efficacy was evaluated by assessing students' performance in completing a set of tasks when performing ultrasound on a dog. Group one received training with the models, group two received prior training without the models and the group three received no training. Entry and exit questionnaires assessed students' confidence in ultrasound scanning having used the models. Student questionnaires showed that students enjoyed using the models and found them more useful than existing teaching aids. It was also found that the models produced better practical skills in students that trained with them, in comparison to existing teaching. The models were easy to make, produced good images, and are reusable.

The ultrasonographic appearance of renal medullary striations and their association with renal disease and renal histopathology in domestic cats.

Medullary striations (MS) have been anecdotally observed on ultrasound of feline kidneys; however, their significance is unknown. Aims of this retrospective, case control, pilot study were to describe the appearance, prevalence, and clinicopathological correlates of MS in a referral feline population. Still images from 1247 feline abdominal ultrasound studies performed between 2011 and 2021 were reviewed. Cats with MS were identified and compared with age-matched controls. Serum urea, creatinine, calcium, phosphate, and calcium-phosphate-product, plus urine specific gravity, urine protein: creatinine ratio (UPC), prevalence of active sediment (defined as > 5 red (RBC) or white blood cells (WBC) per high-power field) and prevalence of positive urine culture were compared between MS and control groups using the Mann-Whitney U test or Fisher's Exact test. Data are presented as median [range]. 27 cats were identified as having MS, giving a prevalence of 2.2% with a significantly higher proportion being seen in males (P = 0.018). Medullary striation cats had significantly higher UPC values than controls (0.46 [0.16-7.57] vs. 0.16 [0.07-2.27]; P = 0.006). Cats with MS were more likely to have active urinary sediments (39% vs 8%, P = 0.023), but no difference in prevalence of positive urinary cultures was observed between groups. There was no significant difference in other parameters between MS and control cats. Renal histopathology performed in three MS cats revealed focal regions of linear medullary fibrosis. Medullary striations are associated with proteinuria and urinary tract inflammation in cats, which may reflect renal tubular dysfunction and/or inflammation. Hence identification might allow for earlier detection of renal pathology.

Ultrasonography as a sensitive and specific diagnostic modality for the detection of ectopic ureters in urinary incontinent dogs.

Ultrasonography is a widely available diagnostic modality for the identification of dogs with suspected ureteral ectopia; however published studies detailing its sensitivity and specificity are currently lacking. The aim of this retrospective, descriptive, diagnostic accuracy study was to evaluate the sensitivity and specificity of ultrasonography for the diagnosis of ureteral ectopia in incontinent dogs presenting to a referral institution, using cystoscopy as the gold standard. Medical records of urinary incontinent dogs presenting to a single institution (n = 38) were retrospectively reviewed for the presence of ureteric insertion abnormalities and concurrent urinary tract abnormalities. Ultrasonographic findings were compared with those from cystoscopic examination to determine diagnostic accuracy. The relationship between the presence of concurrent urinary tract abnormalities and ureteral ectopia was assessed using an independent samples t-test and Mann-Whitney test. Statistical significance was set at P ≤ 0.05. Ultrasonography had a sensitivity of 93.5%, specificity of 100%, and diagnostic accuracy of 95% when identifying dogs with ureteral ectopia. When classifying individual ureters as ectopic or non-ectopic, sensitivity was 87.8% and specificity was 86.7%. Dogs with ureteral ectopia had significantly more concurrent urinary tract abnormalities on ultrasound than unaffected dogs (P = 0.004). Ectopic ureters were associated with significantly more concurrent ipsilateral upper urinary tract ultrasonographic abnormalities than unaffected ureters (P < 0.001). Ultrasonography performed by an experienced ultrasonographer is a sensitive and specific screening tool for canine ureteral ectopia, which eliminates the need for heavy sedation, general anesthesia, and advanced imaging, although it should not be relied upon as the sole diagnostic modality for the assessment of individual ureters.

Imaging characteristics of thoracolumbar spinal stenosis due to articular process hyperplasia and degenerative joint disease in six large breed dogs.

Previous studies have reported evidence that thoracolumbar articular process hyperplasia and degenerative joint disease may be a cause of stenotic myelopathy in large breed dogs; however, detailed descriptions of imaging characteristics are currently lacking. The aim of this retrospective, multi-center, case series report was to describe imaging findings in six large breed dogs diagnosed with thoracolumbar articular process hyperplasia and degenerative joint disease causing vertebral canal stenosis. All dogs presented with progressive paraparesis, proprioceptive ataxia of the pelvic limbs, and neuroanatomical localization of T3-L3 myelopathy. All dogs underwent magnetic resonance imaging (MRI) of the thoracolumbar spine and had articular process malformations at T13-L1 (three German Shepherd dogs (GSD) and a Boxer dog) or T12-T13 (two mixed-breed dogs). Five cases were managed surgically. Findings provided more detailed imaging descriptions and supported previously published studies indicating that maldevelopment of articular processes and secondary degenerative changes can be a cause of thoracolumbar spinal stenosis and myelopathy in large breed dogs. While uncommon, this condition should be included as a differential diagnosis for large breed dogs presenting with a T3-L3 myelopathy.

Multimodality characteristics of multifocal choroid plexus carcinoma with bilateral calvarial defects in a dog.

An 8-year-old male intact miniature poodle presented for blindness, obtundation, tetraparesis, and vestibular signs. Magnetic resonance imaging, radiography, and ultrasound revealed a left piriform lobe lesion, right cerebellar and left brainstem lesions, and hydrocephalus and bilateral calvarial defects. Histopathology confirmed a choroid plexus carcinoma with meningeal and intraventricular metastases. The calvarial defect did not show evidence of necrosis, osteoclastic resorption, inflammation or neoplastic infiltration, reflecting a quiescent calvarial atrophy or dysplasia. These novel findings supported inclusion of bone atrophy secondary to chronic increased intracranial pressure as a differential diagnosis for large calvarial defects in dogs with choroid plexus carcinoma.

CT characteristics of primary splenic torsion in eight dogs.

Splenic torsion is a rare potentially life-threatening condition characterized by rotation of the spleen around the gastrosplenic and phrenosplenic ligaments leading to occlusion of venous drainage and arterial supply. This retrospective study describes the CT characteristics for dogs with surgically confirmed splenic torsion from 2013 to 2018 using the submissions to a large multinational teleradiology database. Eight dogs had the splenic torsion confirmed with surgery. Seven of eight cases had histology confirming congestion, hemorrhage, and necrosis, and one had concurrent myelolipoma infiltration. The CT characteristics included an enlarged (8/8), rounded (7/8), folded C-shaped spleen (8/8) with a difference of median parenchymal attenuation between pre- and postcontrast of +1.15 HU (Hounsfield units). Other common features included a mainly homogeneous parenchyma on pre- and post-contrast images (6/8), lack of subjective and objective vascular and parenchymal contrast enhancement (6/8) and free peritoneal fluid (6/8). A "whirl sign" was seen in the majority of cases (7/8) alongside a strongly hyperattenuating center (95-416 HU) on the precontrast images (5/7), which has not been previously described in the veterinary literature. Gastric position was normal in all cases. More variable CT characteristics of the confirmed torsions were attributable to suspected partial torsion and myelolipomatous infiltration. Overall, primary splenic torsion confirmed with surgery showed consistent characteristics on CT.

Objective effectiveness of and indications for laser-assisted turbinectomy in brachycephalic obstructive airway syndrome.

OBJECTIVE: To evaluate the effectiveness of laser-assisted turbinectomy (LATE) in treating brachycephalic obstructive airway syndrome (BOAS) and to investigate the potential indications. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Client-owned pugs, French bulldogs, and English bulldogs (n = 57). METHODS: A BOAS index was obtained from whole-body barometric plethysmography before BOAS conventional multilevel surgery (CMS) and 2-6 months post-CMS. Dogs with BOAS index >50% and BOAS functional grades II-III after CMS were considered candidates for LATE. A BOAS index was repeated 2-6 months after LATE. Intranasal lesions and a measurement of soft tissue proportion at the rostral entrance of choanae (STC) were recorded on the basis of computed tomography images. Logistic regressions were used to assess the intranasal predictors for being LATE candidates. RESULTS: Twenty-nine of 57 dogs were candidates for LATE, all of which were pugs or French bulldogs. The median BOAS index of dogs that were operated on (20/29 candidates) decreased from 67% post-CMS to 42% after LATE (P < .001). Soft tissue proportion at the rostral entrance of choanae was the only predictor for candidacy for LATE. Pugs (P = .021; cutoff = 64%) and French bulldogs (P = .008; cutoff = 55%) with higher STC were more likely to be candidates for LATE. After LATE, 12 of 20 dogs had temporary episodes of reverse sneezing, and nasal noise was noted in 8 of 20 dogs when sniffing and excited. CONCLUSION: Laser-assisted turbinectomy was an effective treatment for dogs with intranasal abnormalities and a poor response to CMS. Soft tissue proportion at the rostral entrance of choanae was a predictor of candidacy for LATE in pugs and French bulldogs. CLINICAL SIGNIFICANCE: Computed tomography-based measurement of STC can be used to predict whether LATE is required in addition to CMS in pugs and French bulldogs with BOAS.

Endotracheal tube placement during computed tomography of brachycephalic dogs alters upper airway dimensional measurements.

Computed tomography (CT) is used to document upper airway lesions in dogs with brachycephalic obstructive airway syndrome. The presence of an endotracheal tube during CT scanning is often required for general anesthesia. We hypothesized that the endotracheal tube placement would change the soft tissue dimensions of the upper airway. The aims of this prospective, method comparison study were to evaluate the reliability of the previously reported upper airway CT measurements with endotracheal tube placement, and to propose measurements that are minimally affected by the endotracheal tube. Twenty brachycephalic dogs were included in this study. Each dog underwent head/neck CT with an endotracheal tube, followed by a second scan without the endotracheal tube. Ten measurements of the soft palate, nasopharynx, and trachea were performed. Tracheal dimension was significantly larger with the endotracheal tube compared to without, whereas the soft palate cross-sectional area was significantly smaller with the endotracheal tube than without the endotracheal tube. The influence of the endotracheal tube on the caudal nasopharynx cross-sectional (transverse-sectional) area varied with a mean proportional absolute difference of 35%. Rostral soft palate thickness, tracheal perimeter, and cross-sectional area of the rostral nasopharynx were the measurements least affected by the endotracheal tube (intraclass correlation coefficient = 0.964, 0.967, and 0.951, respectively). Therefore, we proposed that these three measurements may be most useful for future brachycephalic obstructive airway syndrome studies that require CT scanning of intubated animals. However, with endotracheal tube placement, measurements of soft palate length, caudal nasopharyngeal cross-sectional area, and trachea height and width may not be reliable.

Clinicopathological and diagnostic imaging findings in a dog with neurocandidiasis.

Neurocandidiasis is systemic candidiasis with central nervous system involvement. This case report describes the clinical presentation, diagnostic test results, and histopathology of a dog with neurocandidiasis. A 3-year-old German shepherd dog was presented for a 3-day history of abnormal mentation, neck pain, and ataxia. Magnetic resonance imaging (MRI) scan of the brain revealed multifocal, small, round, intra-axial lesions within the forebrain. Examination of the cerebrospinal fluid revealed severe neutrophilic inflammation. Extensive testing for infectious diseases was negative. The dog was administered immunosuppressive doses of corticosteroids. The dog's clinical signs improved transiently but got worse 12 days after starting the treatment. Repeat MRI scan revealed multiple, intra-axial, target-like nodular lesions scattered throughout the brain parenchyma. In the temporal muscles, nodules were seen. Cytology of the fine needle aspirates of the nodules in the temporal muscles revealed a neutrophilic inflammation with hyalohyphomycosis. Postmortem examination was compatible with a severe systemic fungal infection. Candida albicans was isolated from the brain, kidney, and heart.

The spinal cord-to-vertebral canal area ratio measured with computed tomography is lower in the thoracolumbar than the cervical region in French Bulldogs.

OBJECTIVE: To compare spinal cord-to-vertebral canal area ratios measured with CT between the cervical and thoracolumbar regions in French Bulldogs. ANIMALS: 37 French Bulldogs presented to a referral hospital between 2016 and 2019. PROCEDURES: The study was conducted as a retrospective observational study. Exclusion criteria were evidence of vertebral malformations or spinal cord compression at the sites where measurements were obtained and the presence of cervicothoracic or thoracolumbar transitional vertebrae or neurologic deficits. CT images were reviewed, and measurements were performed by 2 investigators. Measurements of the spinal cord and vertebral canal were made at the level of or immediately cranial to the midbodies of C5 and L1. RESULTS: A 2-tailed, paired t test indicated that the mean spinal cord-to-vertebral canal area ratio differed significantly (P < .01) between C5 (0.726) and L1 (0.605). The ratio was lower in the thoracolumbar region, suggesting that the vertebral canal was relatively larger in this region. CLINICAL RELEVANCE: The epidural space did not appear to be larger in the cervical than in the thoracolumbar region in this population of French Bulldogs, contrary to previous reports. The reason for the more severe deficits observed with thoracolumbar disk extrusion in this breed remains to be characterized.

Primary histiocytic sarcoma in the brain with renal metastasis causing internal ophthalmoparesis and external ophthalmoplegia in a Maine Coon cat.

CASE SUMMARY: An 11-year-old neutered male Maine Coon cat was presented for investigation of anisocoria and depression. Neurological examination was consistent with a lesion at the level of the middle cranial fossa, and biochemistry was indicative of moderate renal functional impairment. MRI of the brain identified an extra-axial mass lesion at the level of the middle cranial fossa, T2-weighted hyperintense and strongly homogeneously contrast enhancing with dural tail. The cat was euthanased after 6 weeks of palliative treatment with corticosteroids. Histopathology and immunohistochemistry of the brain, the intra-cranial mass and the renal masses found on necropsy were consistent with histiocytic sarcoma. RELEVANCE AND NOVEL INFORMATION: Central nervous system histiocytic sarcoma is a rare finding in cats. This original case report describes the neurological presentation, novel MRI characteristics and pathological findings of suspected primary histiocytic sarcoma affecting the brain with renal metastasis in a cat.

Myoclonus and hypercalcemia in a dog with poorly differentiated lymphoproliferative neoplasia.

A 1-year, 8-month-old Rhodesian Ridgeback was presented with obtundation, ambulatory tetraparesis, and myoclonus. Initial clinical findings included ionized hypercalcemia with an apparent marked increase in parathyroid hormone, thrombocytopenia, and nonregenerative anemia. Low numbers of circulating atypical cells were noted on blood film evaluation. Brain magnetic resonance imaging identified an extra-axial contrast enhancing subtentorial lesion, and cerebrospinal fluid (CSF) analysis documented a marked atypical lymphocytic pleocytosis. Flow cytometry performed on the CSF demonstrated expression of only CD45, CD90, and MHC class II, with Pax5 positivity on subsequent immunohistochemistry. The final diagnosis was of B-cell lymphoblastic lymphoma or acute leukemia, given the distribution of disease and the presence of significant bone marrow infiltration alongside an aggressive clinical course. The unusual immunophenotype of the neoplastic cells and hypercalcemia presented antemortem diagnostic challenges, highlighting the need for a multidisciplinary approach and caution in the interpretation of clinical abnormalities in cases with multiple comorbidities.