Spontaneous acute and chronic spinal cord injuries in paraplegic dogs: a comparative study of in vivo diffusion tensor imaging.

STUDY DESIGN: Prospective observational-analytical study. OBJECTIVES: Description of diffusion tensor imaging (DTI) metrics obtained from the spinal cord (SC) of dogs with severe acute or chronic spontaneous, non-experimentally induced spinal cord injury (SCI) and correlation of DTI values with lesion extent of SCI measured in T2-weighted (T2W) magnetic resonance imaging sequences. SETTING: Hannover, Germany. METHODS: Forty-seven paraplegic dogs, 32 with acute and 15 with chronic SCI, and 6 disease controls were included. T2W and DTI sequences of the thoracolumbar spinal cord were performed. Values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were obtained from the epicentre of the lesion and one SC segment cranially and caudally and compared between groups. Pearson's correlation coefficient was calculated between DTI and T2W metrics. RESULTS: During acute SCI, FA values were increased (P=0.0065) and ADC values were decreased (P=0.0099) at epicentres compared to disease controls. FA values obtained from dogs with chronic SCI were lower (P<0.0001 epicentres and caudally; P=0.0002 cranially) and ADC showed no differences compared to disease control values. Dogs with chronic SCI revealed lower FA and higher ADC compared to dogs with acute SCI (P<0.0001 for both values at all localisations). FA values from epicentre and cranially to the lesion during chronic SCI correlated with extent of lesion (r=0.5517; P=0.0052 epicentres and r=0.6810; P=0.0408 cranially). CONCLUSION: Using DTI, differences between acute and chronic stages of spontaneous canine SCI were detected and correlations between T2W and DTI sequences were found in chronic SCI, supporting canine SCI as a useful large animal model.

Comparison of Preoperative Quantitative Magnetic Resonance Imaging and Clinical Assessment of Deep Pain Perception as Prognostic Tools for Early Recovery of Motor Function in Paraplegic Dogs with Intervertebral Disk Herniations.

BACKGROUND: Prognostic tools to predict early postoperative motor function recovery (MFR) after thoracolumbar intervertebral disk herniation (IVDH) in paraplegic dogs represent an opportunity to timely implement novel therapies that could shorten recovery times and diminish permanent neurological dysfunctions. HYPOTHESIS: Fractional anisotropy (FA) values obtained using diffusion tensor imaging have a higher prognostic value than a lesion extension ratio in T2-weighted images (T2W-LER) and clinical assessment of deep pain perception (DPP) for MFR. ANIMALS: Thirty-five paraplegic dogs with diagnosis of acute or subacute thoracolumbar IVDH. METHODS: Prospective, descriptive observational study. At admission, absence or presence of DPP, T2W-LER, and FA values was evaluated. MFR was assessed within 4 weeks after decompressive surgery. Values of T2W-LER and FA of dogs with and without MFR were compared using t-tests. All 3 methods were evaluated for their sensitivity and specificity as a prognostic factor. RESULTS: No differences were found between groups regarding T2W-LER. FA values differed statistically when measured caudally of lesion epicenter being higher in dogs without MFR compared to dogs with MFR (P = .023). Logistic regression analysis revealed significance in FA values measured caudally of the lesion epicenter (P = .033, area under the curve = 0.72). Using a cutoff value of FA = 0.660, the technique had a sensitivity of 80% and a specificity of 55%. Evaluation of DPP had a sensitivity of 73.3% and specificity of 75% (P = .007). CONCLUSIONS AND CLINICAL IMPORTANCE: Evaluation of DPP showed a similar sensitivity and a better specificity predicting early MFR than quantitative magnetic resonance imaging.

Invasive histiocytic sarcoma of the lumbar spine in a ferret (Mustela putorius furo).

This report describes the history, clinical examination and histopathology of a histiocytic sarcoma in a domestic ferret. Clinical signs were acute paraplegia and dysuria. Physical examination revealed a firm, smooth, touch-sensitive mass in and around the lumbar vertebral column. Neurologic examination was consistent with a lesion between spinal cord segments T3 and L3. Magnetic resonance images revealed bone lesions of L2 and L3 combined with compression of the spinal cord due to a homogenous, isointense mass that was diagnosed as a malignant round cell tumour and the ferret was euthanased. Histopathology confirmed the diagnosis of an infiltrative histiocytic sarcoma.

[Myocardiosis in a 6-month-old Lawson's Dragon (Pogona henrylawsonii)]. / Myokardiose bei einer 6 Monate alten Zwergbartagame (Pogona henrylawsonii).

In a 6-month-old, chronically inappetent Lawsons's Dragon (Pogona henrylawsonii) with stunted growth a hyperdense cardiac region was found using radiology and computed tomography. At necropsy a profound necrosis of the myocardium with dystrophic calcification was diagnosed. In contrast to the frequently seen metastatic mineralisation of soft tissues, mainly due to poor husbandry, primary tissue destruction is the cause for dystrophic calcification. In reptiles, this is a rarely described form of calcification. Possible causes are infectious processes, nutritional or metabolic insufficiencies, intoxications or genetic components. In the presented case the aetiology could not be determined. In conclusion, dystrophic calcifications should be considered as a differential diagnosis in reptiles with soft tissue mineralisation.

Preorbital carcinoma in two Kirk's dik-diks (Madoqua kirkii).

Two Kirk's dik-diks suffered from chronic, unilateral, therapy-resistant enlargement of the preorbital gland. Computed tomographic imaging revealed a homogenous preorbital mass destroying the adjacent maxillary bone in one animal. Squamous cell carcinoma was diagnosed microscopically in both cases. Immunohistochemically, the neoplastic cells uniformly expressed cytokeratin (CK) 5/6 and CK14. Additionally, tumour cells were strongly labelled for p53 suggesting a possible role of this tumour suppressor gene in tumorigenesis. Chronic obstruction of the preorbital gland due to excessive accumulation of secretory products is considered as a likely cause of glandular and periglandular inflammation with subsequent malignant transformation.

Suspected primary glioblastoma multiforme in the canine spinal cord.

An eight-year-old mixed-breed dog was presented with progressive paraparesis. Neurological examination revealed a painful diffuse lesion between spinal cord segments T3 and L3. Magnetic resonance images displayed multi-focal contrast enhancing spinal cord and meningeal lesions. Cytology of these lesions revealed a malignant tumour prompting euthanasia of the dog. Histopathology confirmed the cytological diagnosis and a final diagnosis of a glioblastoma multiforme was made based on immunohistochemistry.

[Computed tomography diagnosis of a retrobulbar abscess in a white tiger]. / Computertomographische Diagnostik eines retrobulbären Abszesses bei einem weißen Königstiger.

SUBJECT: Etiologic diagnosis of a retrobulbar process is essential for the initiation of a causative therapy. Penetrating foreign bodies and tooth root abscesses, but also neoplastic processes have to be considered as a differential diagnosis for a retrobulbar swelling. The objective of this case report of a tiger with a retrobulbar process was to demonstrate the diagnostic value of computed tomography for making a causative diagnosis. MATERIAL AND METHODS: General examination of the tiger as well as subsequent computed tomography and surgical extraction of a fractured fourth premolar tooth of the left upper jaw was carried out under general anaesthesia. Collected alveolar tissue samples underwent cytological, histopathological and microbiological analyses. RESULTS AND CLINICAL RELEVANCE: Computed tomography was able to allocate the origin of the retrobulbar abscess to the left 4th premolar tooth of the upper jaw. The cytological, histopathological and microbiological examination of the recovered alveolar material confirmed the diagnosis of purulent-necrotic abscess-forming inflammation as a result of a mixed bacterial infection. The present case report demonstrates the diagnostic accuracy of computed tomography for the diagnosis of a retrobulbar process of unknown origin.