Material in the middle ear of dogs having magnetic resonance imaging for investigation of neurologic signs

The aim of this study was to determine the prevalence and potential significance of finding material in the middle ear of dogs having magnetic resonance (MR) imaging. Of 466 MR studies reviewed, an increased signal was identified in the tympanic bulla in 32 (7%) dogs. Cavalier King Charles spaniels, Cocker spaniels, Bulldogs, and Boxers were over-represented compared to the population of dogs having MR imaging. Five (16%) dogs had definite otitis media and one (3%) had a meningioma invading the middle ear. Of the remaining dogs, 13 (41%) had possible otitis media and 13 (41%) had neurologic conditions apparently unrelated to otitis media. The most common appearance of material in the middle ear was isointense in T1-weighted images and hyperintense in T2-weighted images. There was no apparent correlation between the signal characteristics of the material and the diagnosis. Enhanced signal after gadolinium administration was observed affecting the lining of the bulla in dogs with otitis media and in dogs with unrelated neurologic conditions. In dogs without clinical signs of otitis media, finding an increased signal in the middle ear during MR imaging may reflect subclinical otitis media or fluid accumulation unrelated to inflammation. Brachycephalic dogs may be predisposed to this condition.     

COMPARISON OF MAGNETIC RESONANCE IMAGING AND MYELOGRAPHY IN 18 DOBERMAN PINSCHER DOGS WITH CERVICAL SPONDYLOMYELOPATHY

Eighteen Doberman pinscher dogs with clinical signs of cervical spondylomyelopathy (wobbler syndrome) underwent cervical myelography and magnetic resonance (MR) imaging. Cervical myelography was performed using iohexol, followed by lateral and ventrodorsal radiographs. Traction myelography was performed using a cervical harness exerting 9 kg of linear traction. MR imaging was performed in sagittal, transverse, and dorsal planes using a 1.5 T magnet with the spine in neutral and traction positions. Three reviewers independently evaluated the myelographic and MR images to determine the most extensive lesion and whether the lesion was static or dynamic. All reviewers agreed with the location of the most extensive lesion on MR images (100%), while the agreement using myelography was 83%. The myelogram and MR imaging findings agreed in the identification of the affected site in 13-16 dogs depending on the reviewer. MR imaging provided additional information on lesion location because it allowed direct examination of the spinal cord diameter and parenchyma. Spinal cord signal changes were seen in 10 dogs. Depending on the reviewer, two to four dogs had their lesions classified as dynamic on myelography but static on MR images. Myelography markedly underscored the severity of the spinal cord compression in two dogs, and failed to identify the cause of the signs in another. The results of this study indicated that, although myelography can identify the location of the lesion in most patients, MR imaging appears to be more accurate in predicting the site, severity, and nature of the spinal cord compression.     

MAGNETIC RESONANCE IMAGING FEATURES OF PRIMARY BRAIN TUMORS IN DOGS

Magnetic resonance images of twenty-five dogs with histopathologically confirmed primary brain tumors were evaluated. A lesion was visible in each dog. Meningiomas were extra-axial lesions that enhanced markedly withj gadolinium-DTPA. Glimas were Characteized by intra-axial location, significant mass effect and surrounding edema, and variable enhancement patterns. Choroid plexus tumors and pituitary tumors were differentiated by their location and marked enbancement. Prediction of general typeof tumor was correct in 24 of 25 dogs.     

MRI features of CNS lymphoma in dogs and cats

The magnetic resonance (MR) imaging features of central nervous system lymphoma in eight dogs and four cats are described. Intracranial lesions affected the rostrotentorial structures in six dogs and caudotentorial structures in two cats. Lesions affected the spinal cord in two dogs and in two cats. One dog and one cat with intracranial lymphoma had signs of local extracranial extension and lymphadenopathy. Lesions were considered extraparenchymal in four dogs and three cats, intraparenchymal in two dogs and one cat, and appeared to have both intra- and extraparenchymal components in two dogs. All lesions were hyperintense in T2-weighted images when compared to white matter, most were hypointense in T1-weighted images (7/12), and most were hyperintense in fluid-attenuated inversion recovery (FLAIR) images (5/9). When compared to grey matter, these lesions appear either isointense (5/12) or hyperintense (7/12) on T2-weighted images, half of them were hypointense in T1-weighted images (6/12), and most were isointense in FLAIR images (7/9). Lesion margins were usually indistinct in T2-weighted images (10/12) and had perilesional hyperintensity in FLAIR images (7/9). The majority of lesions (10/12) had abnormal meninges around the lesion and half (6/12) had generalized contrast enhancement. Mass effect was evident in all lesions. Although not specific, when combined with the history and neurologic signs, MR features aid presumptive diagnosis that should be confirmed by cytology or histopathology.     

MAGNETIC RESONANCE IMAGING FINDINGS IN 25 DOGS WITH INFLAMMATORY CEREBROSPINAL FLUID

To describe the signs that may be associated with intracranial inflammatory conditions, magnetic resonance (MR) images of 25 dogs that had inflammatory cerebrospinal fluid (CSF) were mixed with those of a control group of 40 dogs that had CSF negative for inflammatory disease and reviewed without knowledge of the clinical signs or diagnosis. CSF was considered inflammatory if the protein level was > 0.25 g/l and the white cell count was > 5 mm(-3). Abnormalities were found by MR imaging in 19 (76%) dogs with inflammatory CSF. Two dogs had focal lesions, 10 had multifocal lesions, and seven had diffuse lesions. Lesions affected all divisions of the brain. Mass effect was identified in seven (28%) dogs, including one that had a choroid plexus carcinoma. Lesions were hyperintense in T2-weighted images in 18 dogs and hypointense in T1-weighted images in six dogs. Multifocal or diffuse intraaxial lesions that were hyperintense in T2-weighted images were observed in 17 (68%) dogs with inflammatory CSF. Administration of gadolinium resulted in enhancement of intraaxial lesions in nine (36%) dogs and enhancement of meninges in seven (28%) dogs. Six (24%) dogs with inflammatory CSF had images interpreted as normal.     

Cerebrospinal fluid analysis and magnetic resonance imaging in the diagnosis of neurologic disease in dogs: a retrospective study

BACKGROUND: Diagnosis of central nervous system (CNS) abnormalities in dogs can be challenging antemortem. Historically, cerebrospinal fluid (CSF) analysis has been used for routine diagnostic evaluation of animals with suspected neurologic disease; however, with increasing availability of magnetic resonance (MR) imaging, the need for concurrent CSF analysis may be questioned. OBJECTIVE: The purpose of this study was to retrospectively assess and compare the diagnostic information contributed from MR imaging and CSF analysis in a population of dogs presenting with neurologic disease. METHODS: Results of concurrent MR imaging and CSF analysis were evaluated in dogs presented for neurologic diseases. Based on clinical diagnosis, the sensitivity of CSF analysis and MR imaging for detecting a nervous system abnormality was calculated. Dogs with diagnoses confirmed by other diagnostic modalities were also evaluated separately. RESULTS: A total of 256 dogs were included in the study. For clinical diagnoses in which abnormalities were expected, MR imaging abnormalities were found in 89% and CSF abnormalities in 75% of dogs; CSF abnormalities were more common than MR imaging abnormalities only in inflammatory CNS disease. The majority of CSF abnormalities were nonspecific; an etiologic diagnosis was determined in only 2% of CSF samples. MR imaging excelled in detecting structural disorders, revealing 98% of vertebral abnormalities. In confirmed cases (n = 55), 76% of MR images and 9% of CSF samples were diagnostic. When intervertebral disk disease (IVDD) and vertebral malformation were excluded from analysis (n = 16 remaining), 25% of MR images and 6% of CSF cytology results were highly indicative of the confirmed diagnoses; CSF titer results provided the diagnosis in 25% of these cases. CONCLUSION: CSF analysis may not be necessary when MR findings of IVDD or vertebral malformation/instability are obvious; however, when the cause of neurologic disorder is uncertain, concurrent MR imaging and CSF analysis provides the greatest assistance in establishing a clinical diagnosis.     

Iatrogenic brainstem injury during cerebellomedullary cistern puncture

Cerebrospinal fluid collection is fundamental to the investigation of central nervous system disorders although it carries potential risks. Herein we report the clinical signs and magnetic resonance (MR) imaging findings associated with needle injury to the brainstem during cerebellomedullary cistern puncture in four dogs. Three dogs were nonambulatory tetraparetic with cranial nerve deficits and one dog had unexplained left thoracic limb paresis. In MR images, there were conspicuous T2 hyperintensities in the myelencephalon in all dogs. In T2* gradient echo images, the lesions were hypointense in two dogs with multiple cranial nerve deficits, and hyperintense in another dog. One dog was euthanized due to sudden neurologic deterioration 12 days later, one died shortly after MR imaging, and a third was euthanized due to concurrent cervical spondylomyelopathy. The fourth dog recovered gradually. Diagnosis was confirmed histopathologically in one dog and was presumptive based on clinical signs and MR findings in three dogs. None of the dogs with cranial nerve deficits recovered, only the one dog with left thoracic limb paresis and concurrent syringomyelia.     

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.     

Bilateral cavernous sinus syndrome in dogs: 6 cases (1999-2004)

OBJECTIVE: To determine clinical features, diagnostic imaging abnormalities, underlying disease, disease progression, and outcome in dogs with bilateral cavernous sinus syndrome. DESIGN: Retrospective study. ANIMALS: 6 dogs. PROCEDURE: Dogs were included if clinical signs consistent with bilateral cavernous sinus syndrome (i.e., deficits of the third, fourth, and sixth cranial nerves and at least 1 of the first 2 branches of the fifth cranial nerve) were present and a lesion of the cavernous sinus was identified by means of diagnostic imaging or postmortem examination. RESULTS: 5 dogs were evaluated because of problems referable to abnormal ocular motility or pupillomotor dysfunction, and 1 dog was evaluated because of partial motor seizures involving the face and bilateral mydriasis. Four dogs had neurologic signs referable to an extrasinusoidal lesion at the time of initial examination, and the remaining 2 dogs eventually developed extrasinusoidal signs. Besides neuroanatomic location, the only consistent neuroimaging feature was variably intense, heterogeneous enhancement of cavernous sinus lesions. Neoplasia was histologically confirmed as the underlying cause in 5 of the dogs and was suspected in the remaining dog. Median survival time for the 4 dogs that were treated was 199 days (range, 16 to 392 days). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that bilateral cavernous sinus syndrome is rare in dogs but should be suspected in dogs with compatible clinical signs. Affected dogs have a poor prognosis, and dogs with clinical signs of bilateral cavernous sinus syndrome should be systematically evaluated for neoplastic disease.     

UTILITY OF MAGNETIC RESONANCE IMAGING FOR DISTINGUISHING NEOPLASTIC FROM NON-NEOPLASTIC BRAIN LESIONS IN DOGS AND CATS

The aim of this study was to identify magnetic resonance (MR) signs that aid differentiation of neoplastic vs. non-neoplastic brain diseases in dogs and cats. MR images of 36 dogs and 13 cats with histologic diagnosis of intracranial disease were reviewed retrospectively. Diagnoses included 30 primary and three metastatic brain tumors, 11 infectious/inflammatory lesions, three vascular, one degenerative disease, and one developmental malformation. Upon univariate analysis of 21 MR signs, there were seven that had a significant association with neoplasia: single lesion (P = 0.004), shape (P = 0.015), mass effect (P = 0.002), dural contact (P = 0.04), dural tail (P = 0.005), lesions affecting adjacent bone (P = 0.008), and contrast enhancement (P = 0.025). Increasing age was also found to be associated with neoplasia (P = 0.0001). MR signs of non-neoplastic brain diseases in dogs and cats were more variable than those of brain neoplasia.     

CLINICAL,PATHOLOGIC, AND MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF CANINE DISC EXTRUSION ACCOMPANIED BY EPIDURAL HEMORRHAGE OR INFLAMMATION

Our aim was to characterize the magnetic resonance (MR) imaging features of canine disc extrusion accompanied by epidural hemorrhage or inflammation. We correlated the imaging characteristics of this type of disc extrusion in 46 dogs and compared these features with clinical signs and pathologic findings. Data from 50 control dogs with MR imaging features of a disc extrusion with no associated hemorrhage or inflammation, characterized by a T2‐hypointense extradural mass, were used for comparison of the relative location of the two types of lesions and prognosis. Disc extrusion causing epidural hemorrhage or inflammation is more common in the caudal aspect of the lumbar spine than disc extrusions that do not cause signs of hemorrhage or inflammation (P<0.05) in MR images. In dogs with disc extrusion and associated epidural hemorrhage or inflammation, there was no association between MR imaging features and signalment, the presence or absence of hemorrhage, or pathologic findings. The appearance of the lesion created by disc extrusion with epidural hemorrhage and inflammation encompasses a wide variety of imaging features, likely related to the duration of the hemorrhage and associated inflammatory changes. In 10 of 46 dogs these secondary changes masked identification of the disc extrusion itself in the MR images. An awareness of the variety of MR imaging features of disc extrusion accompanied by extradural hemorrhage or inflammation is important to avoid making an incorrect diagnosis and to facilitate a proper surgical approach. The prognosis of dogs with disc extrusion accompanied by hemorrhage or inflammation does not appear to be different than for dogs with disc extrusion and without imaging signs of epidural hemorrhage or inflammation.     

Magnetic resonance imaging features of spinal epidural empyema in five dogs.

Spinal epidural empyema is defined an accumulation of purulent material in the epidural space of the vertebral canal. Spinal epidural empyema should be considered as a differential diagnosis in dogs with pyrexia, spinal pain, and rapidly progressing myelopathy. Magnetic resonance (MR) imaging is the imaging test of choice in humans. Here, we describe the MR imaging features of five dogs with confirmed spinal epidural empyema. The epidural lesions appeared as high or mixed signal masses in T2-weighted (T2W) images. Increased signal within the spinal cord gray matter at the site of the lesion was detected in T2W images in all dogs. Two patterns of enhancement were detected on postcontrast T1-weighted (T1W) images. Mild to moderate peripheral enhancement was seen in three dogs and a diffuse pattern of enhancement was seen in one. Discospondylitis was identified in three dogs on T1W postcontrast images. Decompressive spinal surgery was performed in all dogs. Bacteria isolated from the abnormal epidural tissue were Enterobacter cloacae, coagulase-positive Staphylococci, Pasteurella multocida, and Escherichia coli. In one dog bacteria were not isolated. These MR imaging features, along with appropriate clinical signs, can allow prompt diagnosis and appropriate treatment planning.     

REVERSIBLE MAGNETIC RESONANCE IMAGING ABNORMALITIES IN DOGS FOLLOWING SEIZURES

Reversible magnetic resonance (MR) imaging lesions have been described in humans following seizures. This condition has not yet been reported in animals. This paper describes reversible abnormalities identified in 3 dogs using MR imaging that was performed initially within 14 days of the last seizure and follow-up imaging that was performed after 10 to 16 weeks of anticonvulsant therapy. All three dogs had lesions in the piriform/temporal lobes, characterized by varying degrees of hyperintensity on T2-weighted images and hypointensity on T1-weighted images. In one dog, contrast enhancement was evident. On reevaluation, partial resolution occurred in all 3 dogs. In a fourth animal with an olfactory meningioma, similar appearing lesions in the temporal cortex and right and left piriform lobes were identified after seizure activity. A surgical biopsy of the temporal cortex and hippocampus was performed and edema, neovascularization, reactive astrocytosis, and acute neuronal necrosis were evident. These histologic findings are similar to those reported in humans with seizures. Recognizing the potential occurrence of reversible abnormalities in MR images is important in developing a diagnostic and therapeutic plan in canine patients with seizures. Repeat imaging after seizure control may help differentiate between seizure-induced changes and primary multifocal parenchymal abnormalities.     

Clinical signs, magnetic resonance imaging features, and outcome after surgical and medical treatment of otogenic intracranial infection in 11 cats and 4 dogs

Brainstem dysfunction resulting from central extension of infection is a life-threatening complication of otitis media/interna (OMI) that has been described infrequently in dogs and cats. We review the clinical signs of disease, diagnostic findings, and results of surgical and medical treatments of brainstem disease attributable to otogenic intracranial infection in cats and dogs. Eleven cats and 4 dogs were examined because of acute, subacute, or chronic clinical signs of brain disease including central vestibular signs, altered mentation, abnormal posture/gait, cranial nerve deficits, and seizures. Results of a minimal database (CBC, serum biochemical panel, urinalysis, thoracic radiographs, and abdominal ultrasonographic images or radiographs) were within reference intervals in all animals. Magnetic resonance (MR) images of the head were acquired for all animals, and cisternal cerebrospinal fluid (CSF) from 9 of 11 cats and 3 of 4 dogs was examined. Surgical exploration and ventral bulla osteotomy were done for 12 of 15 animals, followed by 1–3 months of antibiotic therapy; the remaining animals were euthanized before treatment. In all animals, MR imaging was effective in characterizing the location and extent of the pathologic changes intracranially as well as within middle/inner ear structures. Results of CSF analysis were characteristic of bacterial infection in most of the animals with acute or subacute disease. Since long-term outcome in all treated animals was very good to excellent, it was concluded that dogs and cats with intracranial disease secondary to extension of otitis media/interna have a good-to-excellent prognosis when the condition was diagnosed and was treated by surgical exploration and appropriate antibiotic therapy.     

Magnetic resonance imaging findings in histologically confirmed Pug dog encephalitis

The purpose of the study was to describe magnetic resonance (MR) imaging features of histologically confirmed necrotizing encephalitis in four Pugs and to compare those findings with MR imaging characteristics of necrotizing encephalitis in other breeds. All dogs had the following common findings: lesions restricted to the forebrain, both cerebral hemispheres diffusely but asymmetrically affected, lesions affected gray and white matter resulting in loss of distinction between both, most severe lesions in occipital and parietal lobes, lesions were irregularly T2-hyperintense and T1-isointense to slightly T1-hypointense, and no cavitation. There were various degrees of contrast enhancement of brain and leptomeninges. Asymmetry of lateral ventricles and midline shift was seen in one dog each. Two dogs had brain herniation, which may have contributed to the progression of neurologic signs. Hyperintensity on T2-weighted and fluid attenuated inversion recovery images in the hippocampus and piriform lobe was consistent with excitotoxic edema, whereas similar imaging features in other forebrain areas corresponded to areas of inflammation or liquefaction on histopathology. In comparison with necrotizing encephalitis in other canine breeds, Pug dog encephalitis has some unique MR imaging features. Therefore, these characteristics cannot be applied to other breeds, nor should imaging features of necrotizing encephalitis of other canine breeds be used for interpretation of MR images in Pug dogs.     

Magnetic resonance imaging findings and clinical associations in 52 dogs with suspected ischemic myelopathy

BACKGROUND: The magnetic resonance imaging (MRI) features of ischemic myelopathy have been described in the human literature and in a small number of cases in the veterinary literature. HYPOTHESIS: The aims of this study were to identify associations among MRI findings, timing of imaging, and presenting neurologic deficits in a large series of dogs with a presumptive diagnosis of ischemic myelopathy. ANIMALS AND METHODS: The medical records and MR images of dogs with a presumptive diagnosis of ischemic myelopathy (2000-2006) were reviewed retrospectively. Inclusion criteria were acute onset of nonprogressive and nonpainful myelopathy, 1.5-tesla MRI of the spine performed within 7 days of onset, and complete medical records and follow-up information. Presumptive diagnosis was based on history, as well as clinical, MRI, and cerebrospinal fluid (CSF) findings. The extent of the lesion on MRI was assessed as the following: (1) the ratio between the length of the hyperintense area on sagittal T2-weighted images and the length of C6 or L2 vertebral body, and (2) the maximal cross-sectional area of the hyperintense area on transverse T2-weighted images as a percentage of cross-sectional area of the spinal cord. RESULTS: Fifty-two dogs met the inclusion criteria. MRI findings were abnormal in 41 dogs and normal in 11 dogs. The presence of MRI abnormalities was not significantly associated with the timing of imaging (P = .3) but was associated with ambulatory status on presentation (P = .04). Severity of signs on presentation was associated with extent of the lesion on MRI (P = .02). CONCLUSION AND CLINICAL IMPORTANCE: The severity of signs on presentation is associated with the presence and the extent of the lesion on MRI.     

MAGNETIC RESONANCE IMAGING FEATURES OF DISCOSPONDYLITIS IN DOGS

The diagnosis of discospondylitis is based mainly on diagnostic imaging and laboratory results. Herein, we describe the magnetic resonance imaging (MRI) findings in 13 dogs with confirmed discospondylitis. In total there were 17 sites of discospondylitis. Eleven (81.1%) of the dogs had spinal pain for >3 weeks and a variable degree of neurologic signs. Two dogs had spinal pain and ataxia for 4 days. Radiographs were available in nine of the dogs. In MR images there was always involvement of two adjacent vertebral endplates and the associated disk. The involved endplates and adjacent marrow were T1‐hypointense with hyperintensity in short tau inversion recovery (STIR) images in all dogs, and all dogs also had contrast enhancement of endplates and paravertebral tissues. The intervertebral disks were hyperintense in T2W and STIR images and characterized by contrast enhancement in 15 sites (88.2%). Endplate erosion was present in 15 sites (88.2%) and was associated with T2‐hypointense bone marrow adjacent to it. In two sites (11.8%) endplate erosion was not MR images or radiographically. The vertebral bone marrow in these sites was T2‐hyperintense. Epidural extension was conspicuous in postcontrast images at 15 sites (88.2%). Spinal cord compression was present at 15 sites (88.2%), and all affected dogs had neurologic signs. Subluxation was present in two sites (11.8%). MRI shows characteristic features of discospondylitis, and it allows the recognition of the exact location and extension (to the epidural space and paravertebral soft tissues) of the infection. Furthermore, MRI increases lesion conspicuity in early discospondylitis that may not be visualized by radiography.     

Fecal incontinence and spinal cord abnormalities in seven dogs

Seven dogs with fecal incontinence and abnormal gaits were evaluated. Fecal incontinence was characterized as defecation of normal stools without posturing. Duration of clinical signs prior to evaluation ranged from 5 months to 3 years. Five dogs had upper motor neuron (UMN) paraparesis, and 2 dogs had UMN tetraparesis. With magnetic resonance imaging, spinal cord abnormalities primarily involving the dorsal aspect of the spinal cord were identified in all dogs. Five dogs had focal abnormalities, and 2 dogs had diffuse abnormalities of the spinal cord. Of the dogs with focal spinal cord lesions, 4 had cystic spinal cord abnormalities and 1 had a meningioma. Surgery was performed on all dogs with focal lesions; 4 of the 5 dogs had resolution of fecal incontinence after surgery. Results in these dogs suggest that fecal incontinence can be associated with spinal cord abnormalities and, depending on the characteristics of the lesion, can resolve after surgical treatment of the abnormality.     

MAGNETIC RESONANCE IMAGING OF OTITIS MEDIA IN A DOG

Otitis media/interna was diagnosed in a 20-month-old German shepherd with the assistance of magnetic resonance (MR) imaging. The MR images were acquired primarily to exclude a brain lesion responsible for vestibular signs. No brain lesion was detected, but obvious signs of chronic changes in the left bulla and external ear canal were confirmed. Thickening of the epithelium and soft tissue surrounding the external ear canal and a laminated appearance of high and low T2 intensities in the tympanic bulla's mucosa were present. The hypointense lines were suspected to be fibrous tissue, indicating chronic changes. This report suggests that MR imaging may serve as a useful imaging tool for otitis media and that it supplies information not obtained with radiography or computed tomography.     

Diagnostic imaging findings and endocrine test results in dogs with pituitary-dependent hyperadrenocorticism that did or did not have neurologic abnormalities: 157 cases (1989-2005)

OBJECTIVE: To compare imaging findings in dogs with pituitary-dependent hyperadrenocorticism (PDH) that did or did not have neurologic abnormalities. Design-Retrospective case series. ANIMALS: 157 dogs with PDH that did (n = 73) or did not (84) have neurologic abnormalities. PROCEDURES: Medical records were reviewed for the presence and nature of clinical signs of CNS disease, and computed tomographic and magnetic resonance images were reviewed for evidence of a pituitary tumor. RESULTS: 60 of the 84 (71%) dogs without neurologic abnormalities and 48 of the 73 (66%) dogs with neurologic abnormalities had a detectable pituitary tumor. However, 17 of the 84 (20%) dogs without neurologic abnormalities had a pituitary macrotumor (ie, a tumor > or = 10 mm in height), and 41 of the 73 (56%) dogs with neurologic abnormalities did not have a detectable pituitary tumor or had a pituitary microtumor. Vague signs of CNS dysfunction (ie, lethargy, inappetence, and mental dullness) were more specific for detection of pituitary macrotumors than were CNS-specific signs (ie, seizure or blindness). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that there was no apparent relationship between a pituitary tumor and development of neurologic abnormalities in dogs with PDH. In addition, neurologic abnormalities in dogs with pituitary macrotumors were often vague (ie, lethargy, inappetence, and mental dullness).