A review of primary central nervous system neoplasms of cats.

Primary central nervous system (CNS) neoplasms are uncommonly diagnosed in cats. The majority of primary feline CNS neoplasms described in the veterinary literature consist of meningioma and glioma occurring mainly in the brain and less often in the spinal cord. Although most neoplasms can be diagnosed based on routine histologic evaluation, less typical tumors need to be further characterized using immunohistochemistry. This review compiles the relevant information about the most common primary CNS neoplasms of cats available in the veterinary literature, aiming to serve as a converging source of information for the topic.

The "Claw Sign" may aid in axial localization in cases of peripherally located canine glioma on MRI.

The "claw sign" is a radiographic sign studied in human imaging to determine if a mass arises from a solid structure or organ versus a close adjacent location, resulting in distortion of the outline of an organ. We investigated its utility in characterizing MRI axial localization of peripherally located intracranial glioma versus meningioma, due to their overlap in MRI appearance. This retrospective, secondary analysis, cross-sectional study aimed to report the sensitivity, specificity, and inter- and intraobserver variabilities using kappa statistics, hypothesizing that the claw sign will have strong inter- and intraobserver agreement (κ > 0.8). Dogs with a histologically confirmed diagnosis of peripherally located glioma or meningioma and available 3T MRI data were retrieved from medical record archives from 2009 to 2021. A total of 27 cases, 11 glioma and 16 meningioma, were included. The postcontrast T1-weighted images were provided to five blinded image evaluators in two separate randomized sessions separated by a 6-week wash out period. Prior to the first evaluation, evaluators were provided with a training video and set of training cases for the "claw sign," which were excluded from the study. Evaluators were asked to rate cases as "positive," "negative," or "indeterminate" for the "claw sign." The sensitivity and specificity for the "claw sign" for the first session were 85.5% and 80%, respectively. The interobserver agreement for identifying the "claw sign" was moderate (κ = 0.48), and the intraobserver agreement across the two sessions was substantial (κ = 0.72). These findings indicate the claw sign is supportive but not pathognomonic for intra-axial localization in cases of canine glioma on MRI.

MRI and CT characteristics of a grade I meningioma with concurrent cribriform plate lysis in a dog.

A 6-year-old female spayed German Shepherd mixed-breed dog was presented for treatment of a frontal lobe mass diagnosed on MRI, after an acute onset of generalized seizures and behavior changes. Computed tomography of the head was performed for radiation therapy planning and revealed concurrent cribriform plate lysis without nasal sinus invasion, and focal lysis of the left ventrolateral cranial fossa. Histopathology of the mass obtained via surgical excision was consistent with a grade I fibrous meningioma. The dog had a good outcome following surgery and radiation therapy.

Computed tomographic, magnetic resonance imaging, and ultrasonographic characteristics of retrobulbar meningiomas in 15 dogs.

Meningioma is the most common tumor of the cranium in dogs and an important differential diagnosis for a potentially treatable disease that can be found in the periorbital tissues. The objective of this retrospective, case series study was to describe the CT, MRI, and US characteristics of confirmed retrobulbar meningiomas in a group of dogs. Medical records from multiple institutions were searched for canine patients with CT, MRI, and/or US imaging of a cytologically or histologically confirmed retrobulbar meningioma. Fifteen dogs met the inclusion criteria. Retrobulbar meningiomas typically appeared as a relatively well-defined conical to ovoid mass within the retrobulbar space, most often along the optic nerve and expanding the extraocular muscle cone. On CT, masses were predominantly soft tissue attenuating and variably heterogeneously contrast enhancing. While MRI features were variable, moderate to marked contrast enhancement was seen in all cases. Many of the tumors had evidence of partial mineralization, best appreciated on CT in nine patients, but also suspected based on susceptibility artifacts in three MRI cases, one of which was confirmed on CT. Regional osteolysis was a rare finding, noted in three cases, but was often accompanied by cranial cavity extension (2/3). Cranial cavity extension was also seen in the absence of regional osteolysis, identified in a total of six patients. On US, masses were echogenic and compressed the globe. The findings were consistent with previous gross and histologic descriptions and supported prioritizing retrobulbar meningioma as a differential diagnosis for dogs with the described imaging characteristics.

Use of CT and MR imaging in radiation therapy planning of imaging-diagnosed canine intracranial meningioma achieves better tumor coverage than CT alone.

The aim of this retrospective, secondary analysis study was to quantify the dosimetric impact of the lack of interobserver agreement on gross tumor volume (GTV) delineation for canine meningioma. This study used a previously reported population of 13 dogs with GTVs contoured on CT alone and on registered CT-MR by 18 radiation oncologists. The "true" GTV was generated for each dog using a simultaneous truth and performance-level estimation algorithm, and "true" brain was defined as the whole brain minus true GTV. Treatment plans were generated for each dog and observer combination, using criteria applied to the observer's GTV and brain contours. Plans were then categorized as a pass (met all planning criteria for true GTV and true brain) or fail. A mixed-effects linear regression was performed to examine differences in metrics between CT and CT-MR plans and mixed-effects logistic regression was performed to examine differences in percentages of pass/fail between CT and CT-MRI plans. The mean percent coverage of true GTV by prescribed dose was higher for CT-MR plans than for CT plans (mean difference 5.9%; 95% CI, 3.7-8.0; P < 0.001). There was no difference in the mean volume of true brain receiving ≥24 Gy and in maximum true brain dose between CT plans and CT-MR plans (P ≥ 0.198). CT-MR plans were significantly more likely to pass the criteria for true GTV and true brain than CT plans (OR 1.75; 95% CI, 1.02-3.01; P = 0.044). This study demonstrated significant dosimetric impact when GTV contouring was performed on CT alone compared with CT-MR.

Clinical presentation, diagnostic findings and outcome of dogs undergoing surgical resection for intracranial meningioma: 101 dogs.

BACKGROUND: Meningioma is the most common primary brain neoplasm in dogs. Further information is required regarding the expected long-term prognosis of dogs following the surgical resection of an intracranial meningioma together with the influence of adjunctive therapies. Whilst there have been several studies reporting the long-term outcome of intracranial meningioma resection following surgery alone, surgery with the use of an ultrasonic aspirator, surgery combined with radiotherapy and surgery combined with the addition of hydroxyurea, it is currently unclear which type of adjunctive therapy is associated with the most favourable outcomes. The objective of this study is to describe the presentation and outcome of dogs undergoing surgery for the resection of an intracranial meningioma and the effect of clinical factors, adjunctive therapies and meningioma histopathological subtype on the long-term outcome. RESULTS: A hundred and one dogs that had intracranial surgery for meningioma resection were investigated from four referral centres. 94% of dogs survived to hospital discharge with a median survival time of 386 days. Approximately 50% of dogs survived for less than a year, 25% survived between 1 and 2 years, 15% survived between 2 and 3 years and 10% survived for greater than 3 years following discharge from hospital. One or more adjunctive therapies were used in 75 dogs and the analysis of the data did not reveal a clear benefit of a specific type of adjunctive therapy. Those dogs that had a transfrontal approach had a significantly reduced survival time (MST 184 days) compared to those dogs that had a rostrotentorial approach (MST 646 days; p < 0.05). There was no association between meningioma subtype and survival time. CONCLUSIONS: This study did not identify a clear benefit of a specific type of adjunctive therapy on the survival time. Dogs that had a transfrontal approach had a significantly reduced survival time. Intracranial surgery for meningioma resection offers an excellent prognosis for survival to discharge from hospital with a median long term survival time of 386 days.

Meningioma with rhabdoid features: Pathologic findings in dogs.

Rhabdoid meningioma is a rare type of meningeal neoplasm in humans. This study reports the clinical, pathological, and ultrastructural features of 4 cases of canine meningioma with rhabdoid features. The cases were female and 8 to 12 years of age. Biopsies from complete surgical resections were examined for all cases. The whole brain with tumor recurrence was collected at necropsy in 2 dogs. Histologically, the tumors consisted of discohesive sheets of oval-polygonal cells with abundant eosinophilic cytoplasm and occasional paranuclear hyaline-like inclusions. Cells were intensely immunopositive for vimentin, negative for melan A and S100 protein in all cases, and showed variable immunolabeling for cytokeratin in 2 cases. Focal glial fibrillary acidic protein (GFAP)-immunopositive cells were present in 1 case. Ultrastructurally, the rhabdoid cells in case 1 contained prominent cytoplasmic whorls of intermediate filaments, recapitulating the ultrastructural features of rhabdoid meningioma in humans. In cases 2 and 3, the meningioma cells contained interdigitating cell processes folded in a maze-like fashion resembling rhabdoid-like meningioma in humans. In case 4, the voluminous cytoplasm contained many round-to-flattened mitochondria admixed with rough endoplasmic reticulum, indicating a predominant oncocytic differentiation and not the rhabdoid differentiation suggested by light microscopy. Thus, rhabdoid morphology occurs in different types of meningiomas, and ultrastructural findings are essential for a correct diagnosis.

Bovine intracranial neoplasia: A retrospective case series.

This case series describes the clinical and pathological findings of intracranial neoplasms in cattle, a rare entity. Data and archived tissues from 24 intracranial tumors were reviewed and investigated by immunohistochemistry for S100, glial fibrillary acidic protein, synaptophysin, pancytokeratin, vimentin, neuron-specific enolase, oligodendrocyte transcription factor 2, and isocitrate dehydrogenase 1. Ages of affected cattle ranged from 6 months to 14 years (5.7 ± 3.6 years; mean ± SD). Predominant clinical signs were altered mental state, central vestibular dysfunction, and cerebellar incoordination. Twelve gliomas, all high grade, were the most common tumors observed: oligodendrogliomas (n = 6), astrocytomas (n = 4), and undefined gliomas (n = 2). The oligodendrogliomas were located in the brainstem and extended into the ventricles, whereas all astrocytomas were located in the forebrain. Isocitrate dehydrogenase 1 gene mutation as described in humans was not detected. The 5 meningiomas exhibited microcystic, chordoid, atypical, papillary, and anaplastic subtypes. Metastatic carcinomas (n = 4) were the only secondary tumor type present, and these were located at the level of the medulla with infiltration of cranial nerves and in one case leptomeningeal carcinomatosis. In addition, 2 medulloblastomas and 1 choroid plexus carcinoma were diagnosed. Immunohistochemistry for vimentin and pancytokeratin was particularly useful to distinguish meningiomas and choroid plexus carcinoma (positive for vimentin only) from mestastatic carcinomas (positive for cytokeratin only) as all showed a papillary growth pattern. Overall, the morphological features were comparable with other species and the human and canine classifications could be applied.

High-field MRI using standard pulse sequences has moderate to substantial interobserver agreement and good accuracy for differentiation between intracranial extra-axial histiocytic sarcoma and meningioma in dogs.

Intracranial extra-axial histiocytic sarcoma shares common MRI features with meningioma. As histiocytic sarcoma carries a generally worse prognosis than meningioma, the ability to differentiate between these two neoplasms is of clinical value. The aim of this retrospective diagnostic accuracy and observer agreement study was to evaluate the accuracy and reliability of high-field MRI to differentiate between these two tumors, using standard pulse sequences and published MRI features. A total of 51 dogs were included (26 meningiomas and 25 histiocytic sarcomas). Magnetic resonance imaging examinations were independently assessed by three experienced board-certified radiologists, evaluating 18 imaging features. They were asked to assign each case to one of three categories (meningioma, histiocytic sarcoma, and undetermined). Agreement for the MRI diagnosis across all three reviewers was moderate (κ 0.54) while paired interobserver agreement ranged from moderate to substantial (κ 0.58-0.74) with percent agreement ranging between 86.1% and 87.7%. Overall, the probability of correctly diagnosing meningioma in a dog with this tumor ranged between 79.2% and 94.4%, and the probability of correctly diagnosing histiocytic sarcoma in a dog with this tumor ranged between 76.0% and 92.3%. The overall probability to diagnose the correct tumor, irrespective of type, ranged between 79.2% and 89.7%. Histiocytic sarcomas tended to have more extensive edema and more often had combined perilesional and distant meningeal enhancement affecting both pachy- and leptomeninges, while for meningiomas, meningeal enhancement tended to more commonly be perilesional and pachymeningeal. Imaging features that seemed more useful to make a correct diagnosis included "location/type of meningeal enhancement," "osseous changes in the adjacent neurocranium," "cystic changes," and "herniation severity."

Secondary extracranial paranasal sinus meningioma in a dog.

A 13-year-old Maltese dog was presented for inspiratory stertor. A computed tomography evaluation was performed and revealed an osteoproductive lesion primarily centered over the frontal bone with infiltration of the adjacent maxillary and nasal bones, focal intracranial invasion, and an associated broad-based, contrastenhancing, extra-axial lesion along the longitudinal cerebral fissure. Rhinoscopic and incisional biopsies of the paranasal mass were obtained, and a meningioma was diagnosed histologically. Based on the imaging features and histopathology results, an extracranial paranasal sinus meningioma was diagnosed in this dog. To the authors' knowledge, this is the first case report describing the computed tomographic findings associated with a secondary extracranial paranasal sinus meningioma in a dog. Key clinical message: Meningiomas in dogs can be present outside of the brain case and should be considered a differential for tumors of the paranasal sinuses.

Méningiome extra-crânien secondaire du sinus paranasal chez un chien. Un chien maltais de 13 ans a été présenté pour un stertor inspiratoire. Une évaluation par tomodensitométrie a été réalisée et a révélé une lésion ostéoproductive principalement centrée sur l'os frontal avec une infiltration des os maxillaires et nasaux adjacents, une invasion intracrânienne focale et une lésion extra-axiale à large base associée, augmentant le contraste, le long de la fissure cérébrale longitudinale. Des biopsies rhinoscopiques et incisionnelles de la masse paranasale ont été obtenues et un méningiome a été diagnostiqué histologiquement. Sur la base des caractéristiques d'imagerie et des résultats de l'histopathologie, un méningiome extra-crânien du sinus paranasal a été diagnostiqué chez ce chien. À la connaissance des auteurs, il s'agit du premier rapport de cas décrivant les résultats tomodensitométriques associés à un méningiome extra-crânien secondaire du sinus paranasal chez un chien.Message clinique clé :Les méningiomes chez le chien peuvent être présents en dehors du cerveau et doivent être considérés comme un différentiel pour les tumeurs des sinus paranasaux.(Traduit par Dr Serge Messier).

Magnetic resonance imaging findings and clinical management of suspected intracranial hypovolemia after transfrontal craniotomy in a dog.

OBJECTIVE: To report the diagnosis and clinical management of a case of suspected intracranial hypovolemia (IH) in a dog after resection of a large fronto-olfactory chordoid meningioma. STUDY DESIGN: Clinical case report. ANIMAL: One 8-year-old border collie with forebrain neurological signs caused by a fronto-olfactory extra-axial mass diagnosed by using MRI. METHODS: The dog underwent bilateral transfrontal craniotomy for excision of the mass by using ultrasonic aspiration. Immediate postsurgical MRI revealed complete gross resection with no evidence of early-onset complications such as edema, hemorrhage, mass effect, or pneumoencephalus. However, diffuse symmetric meningeal thickening and contrast enhancement were noted. No complications were noted during surgery or while under anesthesia. RESULTS: Neurological deterioration was observed postoperatively. No abnormalities were detected systemically. Thus, early MRI-confirmed findings and neurological deterioration were suspected to be caused by IH. Conservative treatment consisting of bed rest, gabapentin, and intravenous theophylline was then initiated in addition to steroids, antiepileptic drugs, and antibiotics. A gradual neurological improvement was observed, and the dog was discharged completely ambulatory with moderate proprioceptive ataxia 15 days after surgery. CONCLUSION: The clinical and MRI-confirmed findings reported here are consistent with IH, a well-described syndrome in man. This is the first report of a dog with MRI-confirmed findings consistent with IH describing subsequent response to medical management. CLINICAL SIGNIFICANCE: Intracranial hypovolemia after craniotomy should be considered when there is neurological deterioration and characteristic MRI-confirmed findings.

Skull Base Primary Extracranial Meningioma with Hyperostosis in a Small Mixed-Breed Dog.

A 7 yr old female spayed Chihuahua-terrier mix was presented for a progressive dry, hacking cough over 9 mo, with dyspnea aggravated by eating and drinking. Computed tomography of the skull revealed a large mineral attenuating mass associated with the left skull base, without intracranial involvement. A modified ventral paramedian hypophysectomy approach along the medial aspect of the left ramus was used to approach the base of the skull. Ninety percent of the mass was debulked via high-speed pneumatic burr. Histopathology was consistent with hyperostosis originating from a primary extracranial meningioma (ECM), with the tissue staining positive for vimentin and negative for cytokeratin. The patient was symptom free for 9 mo before clinical signs returned because of tumor recurrence and was euthanized 11 mo postoperation because of diminished quality of life. ECM is uncommonly reported in the dog, and to the authors' knowledge has not previously been reported with hyperostosis or located along the skull base at the level of the tympanic bulla. Additionally, although hyperostosis predominantly occurs as diffuse bone thickening adjacent to a meningioma, proliferative focal hyperostosis is uncommon. Given the findings in this patient, ECM should be considered as a differential diagnosis for osseous skull base masses.

Meningioma and associated cerebral infarction in three dogs.

BACKGROUND: In dogs, meningiomas mostly cause chronic progressive clinical signs due to slow tumor growth. CASE PRESENTATION: In contrast, three dogs were presented with the history of chronic generalized tonic-clonic seizures and peracute deterioration with sudden onset of neurological deficits in accordance with an extensive unilateral forebrain lesion. Magnetic resonance imaging examinations of the dogs revealed a well-delineated extraaxial T2W hyperintense mass in the rostral forebrain with homogeneous contrast enhancement. Additionally, an intraaxial, well-demarcated, unilateral lesion was apparent in the parenchyma supplied by the middle cerebral artery. In two cases, necropsy revealed meningothelial meningioma in the rostral fossa and marked eosinophilic neuronal necrosis, a sign of ischemia, focal malacia, edema and gliosis in the temporal lobe and hippocampus because of a focal thrombosis of the middle cerebral artery. In the third case symptomatic treatment resulted in improvement of clinical signs enabling a good quality of life for the patient. CONCLUSIONS: In dogs with structural epilepsy caused by meningioma, acute deterioration of clinical signs can be associated with ischemic infarctions as a potential complication.

Surgical Treatment of Suspected Meningioangiomatosis in the Thoracolumbar Spinal Cord.

A 5 yr old male neutered Labrador retriever was evaluated for an 8 wk history of a slowly progressive abnormal hind limb gait that did not respond to treatment with nonsteroidal anti-inflammatories. Initial examination findings were mild pelvic limb ataxia and moderate right pelvic limb lameness. A computed tomography with a myelogram was performed and showed a suspected intramedullary spinal mass. MRI was conducted and supported the computed tomography with myelogram findings of a possible intradural spinal mass at L1. A left-sided hemilaminectomy followed by a durotomy at L1 was performed and a firm, tan mass was removed. The histopathologic findings indicated a vascular proliferation most suggestive of a rare proliferative disorder of leptomeningeal blood vessels termed meningioangiomatosis. Although the dog's signs initially worsened after surgery and he was nonambulatory with marked paraparesis, he regained ambulation within 3-4 wk after the operation. Eighteen months after surgery, he was ambulatory with mild hind limb ataxia with no progression of signs. This case suggests that surgical resection of lesions of suspected meningioangiomatosis can result in improvement of clinical signs with a good long-term prognosis.

Definitive-intent intensity-modulated radiation therapy provides similar outcomes to those previously published for definitive-intent three-dimensional conformal radiation therapy in dogs with primary brain tumors: A multi-institutional retrospective study.

Radiotherapy with or without surgery is a common choice for brain tumors in dogs. Although numerous studies have evaluated use of three-dimensional conformal radiotherapy, reports of definitive-intent, IMRT for canine intracranial tumors are lacking. Intensity-modulated radiation therapy has the benefit of decreasing dose to nearby organs at risk and may aid in reducing toxicity. However, increasing dose conformity with IMRT calls for accurate target delineation and daily patient positioning, in order to decrease the risk of a geographic miss. To determine survival outcome and toxicity, we performed a multi-institutional retrospective observational study evaluating dogs with brain tumors treated with IMRT. Fifty-two dogs treated with fractionated, definitive-intent IMRT at four academic radiotherapy facilities were included. All dogs presented with neurologic signs and were diagnosed via MRI. Presumed radiological diagnoses included 37 meningiomas, 12 gliomas, and one peripheral nerve sheath tumor. One dog had two presumed meningiomas and one dog had either a glioma or meningioma. All dogs were treated in the macroscopic disease setting and were prescribed a total dose of 45-50 Gy (2.25-2.5 Gy per fraction in 18-20 daily fractions). Median survival time for all patients, including seven cases treated with a second course of therapy was 18.1 months (95% confidence of interval 12.3-26.6 months). As previously described for brain tumors, increasing severity of neurologic signs at diagnosis was associated with a worse outcome. Intensity-modulated radiation therapy was well tolerated with few reported acute, acute delayed, or late side effects.

Primary extracranial nasopharyngeal meningioma in a dog.

An 8-year-old Labrador Retriever was presented for inspiratory efforts with stertor. A rhinoscopy and a magnetic resonance imaging scan were performed and revealed a naso-pharyngeal mass. The mass was identified in the nasopharynx without meningeal extension. This mass was both T1- and T2-hyperintense, compared to normal brain parenchyma without significant postcontrast enhancement. The mass was surgically removed and the histologic diagnosis was a mesenchymal tumor. Immunohistochemistry with antibodies was conducted and consistent with an extracranial meningioma. To the authors' knowledge, this is the first case report documenting a primary extracranial nasopharyngeal meningioma in a dog.

Atypical and malignant canine intracranial meningiomas may have lower apparent diffusion coefficient values than benign tumors.

Canine intracranial meningiomas can be graded based on histological classification as benign (grade I), atypical (grade II), and anaplastic or malignant (grade III). In people, grade II/III meningiomas behave more aggressively, have a higher potential for recurrence after surgical resection, and have lower apparent diffusion coefficient (ADC) values with diffusion weighted imaging (DWI). In this retrospective analytical cross-sectional study, 42 dogs had ADC values quantified in an attempt to differentiate tumor histologic grade. Our hypothesis was that ADC values would be significantly lower in grade II and III versus grade I meningiomas in dogs. On each ADC image, a polygonal region of interest (ROI) was hand-drawn along the lesion's periphery, excluding fluid-filled and hemorrhagic regions. Mean ADC value (ADCmean ) and minimum ADC value (ADCmin ) were calculated. Additionally, two smaller, ovoid ROI were drawn within the lesion with mean ADC calculated (ADCmean sR and ADCmin sR ). Normalized ADC values using white matter were also calculated (ADCn and ADCn sR ). Grades of each tumor were assigned based on histopathology review. Association between ADC parameters and histological grade was tested by means of two-sample t-tests. There were 14 grade I (33.3%), 25 grade II (59.5%), and three grade III (7.2%) meningiomas. ADCmean sR and ADCmin sR were significantly lower when comparing grade II/III to grade I (P < .05). Grade II tumors had significantly lower ADCmean , ADCmean sR , ADCmin sR , ADCn , and ADCn sR than grade I meningiomas. This preliminary study supports the potential of ADC values to help predict the histological grade of intracranial meningiomas in dogs.

A methodological approach for deep learning to distinguish between meningiomas and gliomas on canine MR-images.

BACKGROUND: Distinguishing between meningeal-based and intra-axial lesions by means of magnetic resonance (MR) imaging findings may occasionally be challenging. Meningiomas and gliomas account for most of the total primary brain neoplasms in dogs, and differentiating between these two forms is mandatory in choosing the correct therapy. The aims of the present study are: 1) to determine the accuracy of a deep convolutional neural network (CNN, GoogleNet) in discriminating between meningiomas and gliomas in pre- and post-contrast T1 images and T2 images; 2) to develop an image classifier, based on the combination of CNN and MRI sequence displaying the highest accuracy, to predict whether a lesion is a meningioma or a glioma. RESULTS: Eighty cases with a final diagnosis of meningioma (n = 56) and glioma (n = 24) from two different institutions were included in the study. A pre-trained CNN was retrained on our data through a process called transfer learning. To evaluate CNN accuracy in the different imaging sequences, the dataset was divided into a training, a validation and a test set. The accuracy of the CNN was calculated on the test set. The combination between post-contrast T1 images and CNN was chosen in developing the image classifier (trCNN). Ten images from challenging cases were excluded from the database in order to test trCNN accuracy; the trCNN was trained on the remainder of the dataset of post-contrast T1 images, and correctly classified all the selected images. To compensate for the imbalance between meningiomas and gliomas in the dataset, the Matthews correlation coefficient (MCC) was also calculated. The trCNN showed an accuracy of 94% (MCC = 0.88) on post-contrast T1 images, 91% (MCC = 0.81) on pre-contrast T1-images and 90% (MCC = 0.8) on T2 images. CONCLUSIONS: The developed trCNN could be a reliable tool in distinguishing between different meningiomas and gliomas from MR images.

Novel use of FaceTime video calling in a deployed setting to assist with the care of a military working dog

Summary: In deployed settings, veterinary recourses are limited and nonveterinary medical providers frequently are required to provide medical treatment to military working dogs (MWDs) until veterinary specialty care can be provided. We present the case of a critically ill MWD who presented initially to a Canadian NATO Role II facility in Iraq that lacked immediate veterinary support. Through the use of FaceTime interactive video calling, the Role II medical providers were able to consult with the MWD unit's veterinarian in the United States and provide effective evaluation, treatment and prioritization of medical evacuation (MEDEVAC). FaceTime video calling was extremely effective and should be considered in future situations where specialist care is not immediately available and transmission of visual information would be beneficial.

Fluorescein sodium-guided resection of intracranial lesions in 22 dogs.

OBJECTIVE: To evaluate the safety of an intraoperative fluorescein sodium (FS) injection and elucidate the relationships between the MRI findings, pathological diagnoses, and intraoperative staining characteristics of intracranial lesions in 22 dogs. STUDY DESIGN: Prospective case series. ANIMALS: Twenty-two dogs with intracranial lesions. METHODS: FS was intravenously administered to 22 dogs undergoing craniotomy for suspected intracranial tumors to evaluate perioperative and postoperative adverse effects. The intensities and patterns of gadolinium (Gd) enhancement on preoperative magnetic resonance imaging and intraoperative FS staining were graded, and their relationship was evaluated. Intraoperative FS staining characteristics and pathological diagnoses were compared. RESULTS: The only adverse effect noted was repetitive vomiting in 2 dogs. The intensities and patterns between preoperative Gd enhancement and intraoperative FS staining appeared to agree. High-grade glioma and histiocytic sarcoma had more intense FS staining. Lesions with strong Gd enhancement, including meningiomas and choroid plexus tumors, also had intense FS staining. CONCLUSION: The intraoperative use of FS is a simple and safe technique to guide the resection of intracranial lesions in dogs. The findings on Gd enhancement, FS staining, and histopathology appeared to agree but require validation in a larger set of cases. CLINICAL SIGNIFICANCE: The intraoperative use of FS may improve the prognosis of dogs with brain tumors by guiding the resection of lesions.