Evaluation of an ultrasound-guided freeze-core biopsy system for canine and feline brain tumors.

Objective: To determine if a single brain biopsy utilizing a freeze-core needle harvest system Cassi II under ultrasound guidance provides a diagnostic sample; to evaluate the technique's efficacy in procuring diagnostic samples in comparison with "open" surgical biopsies; and to describe intraoperative complications associated with the technique. Study design: Experimental clinical study. Animals: Seventeen dogs and four cats with magnetic resonance imaging (MRI) diagnoses of readily surgically accessible intracranial masses. Methods: Immediately prior to surgical biopsy (SB), freeze-core biopsy (FCB) sample was obtained from each patient under ultrasound guidance. Results: Histopathology results from single FCB samples were found to be in 100% agreement with the SB samples. Freezing artifact was minimal and did not interfere with histopathologic interpretation. There were no intraoperative complications specifically attributable to the use of the FCB system. Conclusion: Based on the results of this small experimental study, the FCB system is expected to safely yield diagnostic quality intracranial masses biopsy specimens. Clinical significance: This system has the potential of obtaining diagnostic biopsies of more deeply seated brain lesions (i.e., intra-axial tumors considered inaccessible or with large risks/difficulties by standard surgical means) which would provide a definitive diagnosis to guide appropriate therapy.

Biopsy and histologic findings of the dura mater at the level of the foramen magnum in 121 CKCS with Chiari-like malformation.

To describe histopathologic features found in dural biopsies of Cavalier King Charles Spaniels (CKCS) with Chiari-like malformation (CM) and identify any associations between age, duration of clinical signs, syrinx location or syringomyelia (SM, and quality of life (QOL). The medical records of 121 consecutive client owned CKCS with CM and SM, confirmed by whole body magnetic resonance imaging (MRI), that underwent foramen magnum decompression (FMD) with cranioplasty and durectomy with biopsy from 2006 to 2016 were retrospectively reviewed. Dural biopsies were submitted to a board-certified veterinary pathologist for histopathologic interpretation. The chi-square test was used to analyze associations between histologic findings and categorical variables. For continuous measures, the Kruskal-Wallis non-parametric test was used to compare distributions across pathology categories. A result was considered statistically significant at the p < 0.05 level of significance. The mean age, duration of pre-surgical clinical signs, and pre-operative QOL (1-5 scale) were 44.27 months, 44.78 weeks, and 2.72, respectively. Syringomyelia was found in the cervical region only in 39 of 121 (32.23%) of dogs, in the cervical and thoracic region only in 17 of 121 (14.05%) of dogs, and in the cervical, thoracic, and lumbar region combined in 65 of 121 (53.72%) of dogs. Sixty-six of one hundred twenty-one (54.55%) dural biopsy specimens had histopathology changes; fifty-five (45.45%) did not. Forty-three of one hundred twenty-one (35.54%) dural biopsy specimens had osseous metaplasia, 16 of 121 (13.22%) had evidence of fibrosis, 4 of 121 (3.31%) had arachnoid hyperplasia, and 3 of 121 (2.48%) had evidence of mineralization. Most dogs with CM were found to have histopathologic changes in the dura at the time of FMD cranioplasty was performed. These dural changes can be observed in dogs experiencing clinical signs for a time period as short as 4 weeks prior to presentation. The histopathologic changes were not associated with age, breed, duration of clinical signs, the location of syringomyelia or QOL. The influence of histopathologic changes on long-term prognosis in dogs without dural decompression is unknown since all dogs in this study had dural resection.

The Effects of Mycophenolate on the Formation of Granulation Tissue Post-operatively in Canine Tracheal Stent Patients (2014-2020).

Objectives: To determine if mycophenolate mofetil reduces the incidence and severity of granulation tissue in-growth in canine tracheal stent patients. Study design: Randomized clinical trial. Animals: 111 dogs from the hospital population. Methods: Client-owned dogs that received an endoluminal self-expanding tracheal stent for canine tracheal collapse between 2014 and 2020 were randomly assigned into one of two treatment groups. Control group medication protocol consisted of prednisone 0.5 mg/kg PO BID/SID/EOD × 30 days, hydrocodone 0.25 mg/kg PO TID × 30 days, and cefovecin 8 mg/kg SQ post-placement. Mycophenolate group medication protocol was identical to the control group medication protocol with the addition of mycophenolate mofetil 10 mg/kg PO BID × 30 days, SID for life. Recheck tracheoscopy was performed at 1, 3, and 6 months post-stent placement. Presence and severity of granulation tissue were determined by tracheoscopy and were recorded as a percentage of tracheal lumen obstruction by blinded evaluators (none present, <25%, >25-50%, and >50%). Results: At none of the three time points was there a statistically significant difference in grade between controls and those receiving mycophenolate (p = 0.467, p = 0.330, and p = 0.410). Conclusions and Clinical Significance: Our results suggest that mycophenolate can be safely given to these patients but do not support that its administration will reduce the incidence and severity of granulation tissue. Although a difference was observed in the severity of granulation tissue between the two groups, loss to follow-up may have influenced conclusions. A larger study would be warranted to further evaluate the effect of mycophenolate on the development of granulation tissue.

Histopathologic characteristics of biopsies from dogs undergoing surgery with concurrent gross splenic and hepatic masses: 125 cases (2012-2016).

OBJECTIVE: To investigate the histopathologic characteristics of concurrent splenic and liver masses in dogs undergoing splenectomy and liver mass biopsy/resection. Medical records of 125 client-owned dogs found to have splenic mass or masses and a liver mass or masses during surgery were examined. Signalment (age, sex, breed), body weight, and results of histopathology were recorded for all dogs. RESULTS: Twenty-seven percent (34/125) of the dogs in this study had no evidence of malignancy in either the liver or the spleen. Sixty of 125 dogs (48.0%) had malignancy in the spleen and liver, and 56 (56/60, 93.3%) of those dogs had the same malignancy in both organs. Signalment was similar to that in other reports of splenic pathology. In this clinical population of dogs, 27% of dogs with concurrent gross splenic and liver masses discovered intraoperatively had benign lesions in both locations and therefore had a favorable prognosis.

Medical infrared imaging and orthostatic analysis to determine lameness in the pelvic limbs of dogs.

Subtle lameness makes it difficult to ascertain which is the affected limb. A study was conducted to investigate a change in the thermal pattern and temperature of the thermal image of the paw print in a lame pelvic limb compared to a non-lame pelvic limb of dogs confirmed by orthostatic analysis. Fourteen client owned dogs with a unilateral pelvic limb lameness and 14 healthy employee dogs were examined and the pelvic limbs radiographed. Thermal images of the paw print were taken after each dog was kept in a static position on a foam mat for 30 seconds. Average temperatures and thermographic patterns were analyzed. Analysis was performed in a static position. The asymmetry index for each stance variable and optimal cutoff point for the peak vertical force and thermal image temperatures were calculated. Image pattern analysis revealed 88% success in differentiating the lame group, and 100% in identifying the same thermal pattern in the healthy group. The mean of the peak vertical force revealed a 10.0% difference between the left and right pelvic limb in healthy dogs and a 72.4% between the lame and non-lame limb in the lame dog group. Asymmetry index analysis revealed 5% in the healthy group and 36.2% in the lame group. The optimal cutoff point for the peak vertical force to determine lameness was 41.77% (AUC = 0.93) and for MII 0.943% (AUC = 0.72). The results of this study highlight the change in the thermal pattern of the paw print in the lame pelvic limb compared to a non-lame pelvic limb in the lame group and the healthy group. Medical infrared imaging of the paw prints can be utilized to screen for the lame limb in dogs.

Atlantooccipital Overlap and Other Craniocervical Junction Abnormalities in Dogs.

The term craniocervical junction abnormality (CJA) is an umbrella term for a variety of malformations that occur in the craniocervical region. These abnormalities include Chiari-like malformation, atlantooccipital overlapping, atlantoaxial instability, occipitoatlantoaxial malformations, atlantoaxial dural bands, and dens abnormalities. Syringomyelia can occur secondary to any of these malformations or a combination. Clinical signs in dogs with a CJA typically include neck pain and varying signs associated with a cervical myelopathy. MRI of CJAs with computed tomography imaging is necessary for a full evaluation. Some dogs with CJAs respond to medical management, but for most surgery is the treatment of choice.

Medical Infrared Imaging of Normal and Dysplastic Elbows in Dogs.

OBJECTIVE: To investigate the ability of medical infrared imaging to differentiate between normal canine elbows and those with abnormal elbows (elbow dysplasia). STUDY DESIGN: Prospective cohort study. ANIMALS: Dogs with normal (n = 15) and abnormal (n = 14) elbows. METHODS: Infrared imaging was performed on all dogs and data analyzed via descriptive statistics and image pattern analysis software. Animals with elbow dysplasia had arthroscopic procedures to confirm the presence of elbow disease. RESULTS: Computer recognition pattern analysis was up to 100% correct in identifying abnormal elbows and normal elbows, with the medial images most consistent. The caudal, lateral, and cranial images correctly identified 83-100% abnormal elbows. The caudal and lateral images correctly identified 83% normal elbows. A significant difference in temperature was found between normal and abnormal elbows for the cranial full region of interest, lateral images, and each quadrant. CONCLUSION: Medical infrared imaging was able to correctly identify known abnormal and known normal elbows in dogs.

Medical infrared thermal imaging of cats with hyperthyroidism.

OBJECTIVE: To determine the usefulness of medical infrared thermal imaging (MITI) as a screening tool for hyperthyroidism in cats, evaluate the need for hair clipping over the ventral aspect of the neck to achieve optimal images, and determine whether there is a change in thermal patterns at 1 and 3 months after radioactive sodium iodide I 131 treatment. ANIMALS: 17 cats with and 12 control cats without hyperthyroidism. PROCEDURES: All cats underwent MITI first with the hair present and then after the hair was clipped. Each cat with hyperthyroidism was subsequently appropriately treated SC with radioiodide; reevaluations, including MITI before and after hair clipping and measurement of serum thyroxine concentration, were performed 1 and 3 months after treatment. RESULTS: The MITI had 80.5% and 87.5% accuracy in differentiating hyperthyroid cats from clinically normal cats before and after the hair over the ventral aspect of the neck was clipped. Among cats with an initial serum thyroxine concentration > 4.0 µg/dL, the success rate for MITI-detected response to radioiodide treatment at the 1-month reevaluation was 92.86% in unshaved cats and 85.71% in shaved cats. The success rate for MITI-detected response to radioiodide treatment at the 3-month reevaluation was 100% in unshaved and shaved cats. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that MITI was successful in differentiating between hyperthyroid cats and clinically normal cats and identifying patients with thyroxine concentration within reference interval after radioactive sodium iodide I 131 treatment.

Severe hyperthermia, hypernatremia, and early postoperative death after transethmoidal cavitron ultrasonic surgical aspirator (CUSA)-assisted diencephalic mass removal in 4 dogs and 2 cats.

OBJECTIVE: To report clinical findings including severe hyperthermia and hypernatremia after transethmoidal Cavitron ultrasonic surgical aspirator (CUSA)-assisted diencephalic mass removal. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 4) and 2 cats. METHODS: Medical records (1997-2003) of dogs and cats that had transethmoidal CUSA-assisted diencephalic mass removal were reviewed. Retrieved data were: history, signalment, blood work, neurologic examination findings, MRI results, histopathology, postoperative complications, pre- and postoperative medical therapy, and outcome. RESULTS: Tumor types included: meningioma (n = 3), choroid plexus papilloma (1), astrocytoma (1), and pituitary macroadenoma (1). Median onset of hyperthermia was 3.5 hours (range: 1-6 hours) after extubation; median high temperature at onset was 40.3°C, (range: 39.6-41.7°C). Median onset of hypernatremia (median, 172 mmol/L; range: 168-196 mmol/L) was 4.5 hours (range: 1-9 hours) after extubation. Median time of death after hyperthermia was 10.5 hours (range: 6-13 hours) and after extubation was 13.5 hours (range: 11-15 hours). CONCLUSIONS: Transethmoidal CUSA-assisted diencephalic mass removal is associated with early postoperative hyperthermia, hypernatremia, and death, and cannot be recommended.

Medical infrared imaging (thermography) of type I thoracolumbar disk disease in chondrodystrophic dogs.

OBJECTIVE: To: (1) determine the success of medical infrared imaging (MII) in identifying dogs with TLIVDD, (2) compare MII localization with magnetic resonance imaging (MRI) results and surgical findings, and (3) determine if the MII pattern returns to that of normal dogs 10 weeks after decompression surgery. STUDY DESIGN: Prospective case series. ANIMALS: Chondrodystrophic dogs (n = 58) with Type I TLIVDD and 14 chondrodystrophic dogs with no evidence of TLIVDD. METHODS: Complete neurologic examination, MII, and MRI studies were performed on all dogs. Dogs with type I TLIVDD had decompressive surgery and follow-up MII was performed at 10 weeks. Pattern analysis software was used to differentiate between clinical and control dogs, and statistical analysis using anatomic regions of interest on the dorsal views were used to determine lesion location. Recheck MII results were compared with control and pre-surgical images. RESULTS: Computer recognition pattern analysis was 90% successful in differentiating normal dogs from dogs affected by TLIVDD and 97% successful in identifying the abnormal intervertebral disc space in dogs with TLIVDD. Statistical comparisons of the ROI mean temperature were unable to determine the location of the disc herniation. Recheck MII patterns did not normalize and more closely resembled the clinical group. CONCLUSIONS: MII was 90% successful differentiating between normal dogs and 97% successful in identifying the abnormal intervertebral disc space in dogs with TLIVDD. Abnormal intervertebral disc space localization using ROI mean temperature analysis was not successful. MII patterns 10 weeks after surgery do not normalize.

Micro total hip replacement in dogs and cats.

OBJECTIVE: To describe the surgical technique using power-assisted femoral preparation and clinical outcome in 41 dogs and 2 cats surgically treated with the micro total hip prosthesis. STUDY DESIGN: Retrospective case series ANIMALS: Dogs (n = 41) and 2 cats METHODS: Medical records (January 2007-March 2010) of dogs and cats that had MicroTHR were reviewed. Data regarding implant position, cement mantle quality, concurrent surgery, intra- and postoperative complications, operative time, 3-week and 3-month recheck physical examinations, 3-month pelvic radiograph findings, and interval from surgery to any complication were retrieved. RESULTS: Six dogs had staged bilateral MicroTHR, 35 dogs and 2 cats had unilateral MicroTHR. Median body weight was 8.2 kg (range, 2.1-14.2 kg) whereas for those that had complications (fracture or luxation) it was 8.6 kg (range, 6.6-14.1 kg). Median operative time was 71 minutes (range, 55-105 minutes). Complications included luxations (5 of 49; 10%) and femoral fracture (1; 2%). Lameness grades assigned at the 3-month recheck examination: 39 (80%) animals were grade 1, 6 (12%) were grade 2, and 4 (8%) were grade 3. Forty-five animals (92%) had good or excellent results. CONCLUSIONS: MicroTHR is a practical and effective surgery in small breed dogs and cats with coxofemoral disease.

Risk factors and clinical relevance of positive intraoperative bacterial cultures in dogs with total hip replacement.

OBJECTIVE: To report incidence and relevance of positive intraoperative total hip replacement (THR) bacterial cultures taken at the time of surgical closure in dogs having unilateral THR. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 100) with cemented (CFX), cementless (BFX), or hybrid THR. METHODS: Medical records (January 2007-March 2010) of dogs that had THR were reviewed. Signalment, type and side of THR, concurrent surgery, operative and anesthetic times, intraoperative coxofemoral closing (CC) bacterial culture results, organism cultured, duration of postoperative antibiotic administration, physical examination findings at 3 weeks, 3 months, and at 6 months to 1 year after surgery, radiographic findings at 3 months and between 6 months and 1 year after surgery, and incidence of complications were retrieved. RESULTS: There was a significant difference in duration of surgery between CC culture negative and CC culture positive groups (103.27 minutes versus 122.50 minutes, respectively, P < .038) and in total anesthetic time between CC culture negative and culture positive groups (165.20 minutes versus 189.50 minutes, respectively, P < .038). There was no significant difference between CC culture negative and culture positive groups for median age (30 months versus 39 months, respectively, P < .75), median weight (36.91 kg versus 35.68 kg, respectively, P < .61), median clinical signs (4 months versus 3.5 months, respectively, P < .65), sex (males 44.32% versus females 25.00%, respectively, P < .20), laterality (left 55.68% versus right 50.00%, respectively, P < .71), concurrent surgery (extracapsular lateral imbrication/medial patella luxation/lateral patella luxation [ECLI/MPL/LPL] 22.73% versus none 25.00%, respectively, P < 1.00), and THR type (hybrid 17.05% versus 25.00% respectively; CFX 60.23% versus 75.0%; BFX 22.73% versus 0.0%; Fisher's exact test P < .17). CONCLUSIONS: Surgical and anesthetic duration were significantly associated with positive CC culture results. Positive CC culture results were not associated with adverse results at 3 months and at 6-month to 1-year follow-up evaluation.

Morphometric features of the craniocervical junction region in dogs with suspected Chiari-like malformation determined by combined use of magnetic resonance imaging and computed tomography.

OBJECTIVE: To objectively describe morphometric features of the craniocervical junction region of Cavalier King Charles Spaniels (CKCSs) and non-CKCS dogs with suspected Chiari-like malformation (CLM) and identify associations between these features and the presence of other malformations in this region. ANIMALS: 216 CKCSs and 58 non-CKCS dogs. PROCEDURES: Magnetic resonance and computed tomographic images of the head and craniocervical junction region of patients evaluated because of suspected CLM were assessed for cerebellar compression (CC), ventral spinal cord compression at the C1-C2 articulation (medullary kinking), and dorsal spinal cord compression at the C1-C2 articulation (dorsal compression). A compression index was calculated for each of these 3 locations in each dog. Multiple logistic regression analysis was performed to determine whether breed (CKCS vs non-CKCS) and compression index values were associated with the presence of other craniocervical junction abnormalities. RESULTS: All 274 dogs had CC; medullary kinking was identified in 187 (68.2%) and dorsal compression was identified in 104 (38.0%). Atlantooccipital overlapping (AOO) was identified in 76 (27.7%) dogs. Breed of dog (CKCS vs non-CKCS) and value of CC index were the only significant predictors of AOO. The CKCSs had an almost 5-fold decrease in risk of AOO, compared with the non-CKCS dogs, and the risk of AOO nearly doubled for every 10% increase in CC index. CONCLUSIONS AND CLINICAL RELEVANCE: The anatomic abnormality responsible for CC was AOO in a substantial percentage of dogs suspected to have CLM. The CC index value may be used to help differentiate subtypes of craniocervical junction abnormalities in dogs.

Diagnostic imaging of the canine stifle: a review.

The stifle joint, a common location for lameness in dogs, is a complex arrangement of osseous, articular, fibrocartilaginous, and ligamentous structures. The small size of its component structures, restricted joint space, and its intricate composition make successful diagnostic imaging a challenge. Different tissue types and their superimposition limit successful diagnostic imaging with a single modality. Most modalities exploit the complexity of tissue types found in the canine stifle joint. Improved understanding of the principles of each imaging modality and the properties of the tissues being examined will enhance successful diagnostic imaging.

Thermal imaging of normal and cranial cruciate ligament-deficient stifles in dogs.

OBJECTIVE: To investigate the capability of thermography for differentiation between normal stifles and those with cranial cruciate ligament (CCL) rupture in dogs, initially with a full hair coat and 1 hour after clipping the hair coat. STUDY DESIGN: Prospective study. ANIMALS: Labrador Retrievers (n=6) with normal stifle joints (controls) and adult dogs (n=10) with CCL rupture. METHODS: Thermography was performed before, and 60 minutes after, clipping the hair coat from the pelvic limb. Stifle images were classified as normal or abnormal, then subclassified as clipped and unclipped hair coat. CCL deficiency was confirmed at surgery and thermographic images subsequently classified as abnormal before analysis with image processing software. RESULTS: Using image recognition analysis, differentiation between normal and CCL-deficient stifles in both clipped and unclipped dogs was 85% successful on cranial images, medial, caudal, and lateral images were between 75% and 85% successful. Although there were significant increases in skin temperature after clipping in both groups (P<.0002-.0001), there were no significant temperature differences between normal and CCL-deficient stifles when the entire stifle was examined. CONCLUSION: Thermography was successful in differentiating naturally occurring CCL-deficient stifles in dogs, with a success rate of 75-85%. Clipping is not necessary for successful thermographic evaluation of the canine stifle. CLINICAL RELEVANCE: Thermography may be a useful imaging modality for diagnosis of CCL deficiency in dogs when CCL rupture is suspected but stifle laxity is not evident.

Intracranial arachnoid cysts in dogs.

Intracranial arachnoid cyst (IAC) is an infrequently reported developmental disorder seen primarily in small-breed dogs. It usually occurs in the caudal fossa, in the region of the quadrigeminal cistern. Although still considered uncommon, IAC is being recognized more frequently in veterinary medicine, coinciding with the increased availability of magnetic resonance imaging. In this article, clinical information from previously reported cases of canine IAC is combined with additional case information from our hospitals. Similar to IAC in people, it is thought that canine IAC is often an incidental finding. When IAC is responsible for neurologic disease in dogs, generalized seizures and cerebellovestibular dysfunction are the most common clinical presentations. Medical therapy of IAC focuses on management of increased intracranial pressure and seizures, if the latter are part of the clinical complaints. Surgical therapy of IAC involves either cyst fenestration or shunting the excess fluid to the peritoneal cavity

Effect of limb position on elbow congruity with CT evaluation.

OBJECTIVE: To determine if computed tomographic (CT) measurement of radio-ulnar congruence (RUC) is affected by limb position. STUDY DESIGN: Prospective study. ANIMALS: Labrador Retrievers (n=10). METHODS: Each dog had both elbows imaged in neutral, supination, and pronation positions using helical CT acquisition, at 1 mm increments, in a transverse plane. RUC was calculated using a previously reported method and a new technique using 3-D image processing and measurements determined by a coordinate system. RESULTS: The limits of agreement showed that comparing any pair of elbow positions yielded large discrepancies in measurements with the previously reported technique. Better agreement between pairs of elbow positions with reduced discrepancy was achieved using the 3-D technique. Variation in antebrachium positioning did yield a difference in congruence. CONCLUSIONS: Limb position (supination, pronation) affects elbow congruity measurements using CT analysis. Use of 3-D image processing may allow for improved elbow congruity measurements compared with other 2-D measurement techniques. CLINICAL RELEVANCE: Limb position must be controlled when performing CT evaluation of elbows for incongruity. 3-D imaging appears to be less affected by limb position than conventional 2-D analysis when assessing radioulnar incongruence.

Long-term evaluation of canine perianal fistula disease treated with exclusive fish and potato diet and surgical excision.

The records of 33 dogs that had perianal fistula disease treated with en bloc surgical excision and bilateral anal saculectomy, and that were perioperatively administered an exclusive white fish and potato diet, were reviewed to determine outcome. By 1 year after surgery, 87.9% of the dogs had complete or near-complete resolution of visible fistula disease, while only 20.7% continued to have mild intermittent clinical signs. Fecal incontinence was not reported in any dog. Overall, complications were considerably less in both severity and frequency when compared with previous reports.