RESUMO
Objective: Intervertebral disk (IVD) degeneration usually occurs earlier in chondrodystrophic dog breeds than in other breeds. Spinal cord compression secondary to IVD degeneration is the most common cause of myelopathy in these dogs. Standard magnetic resonance imaging (MRI) sequences permit the identification of IVD degeneration and its consequences on adjacent neurological structures. In human medicine, quantitative MRI sequences, such as magnetization transfer ratio (MTR) sequences, are developed and used to detect early IVD degeneration. This prospective randomized post-mortem comparative study aimed to evaluate the correlation between a qualitative Pfirrmann MRI grading and the MTR values of the IVD in chondrodystrophic dogs. Materials and methods: Vertebral columns of eight canine cadavers were frozen and thawed prior to imaging with T2-weighted and MTR sequences using a 3.0 T high-field MRI. These sequences were reviewed by two observers. A Spearman correlation coefficient was calculated in order to compare the MTR values with the Pfirrmann grade. Pearson correlation coefficients were calculated to evaluate the inter-observer agreement of the delineation of the region of interest (ROI) around the NP and the MTR values. A Wilcoxon-Mann-Whitney test was used to conclude on the significance of the correlation between the MTR values and the Pfirrmann grades. Results: There were 138 intervertebral disks analyzed: 29/138 (21.0%) IVD were grade I, 74/138 (53.6%) grade II, and 35/138 (25.4%) grade III. No grades IV and V were present in this study. Inter-observer agreement for delineation of IVD ROI was fair (r = 0.54) but inter-observer agreement of mean MTR value within the ROI was very good (r = 0.89). Mean MTR values were 16.459% (10.0305-21.0950%) for grade I, 18.888% (10.0750-27.2400%) for grade II, and 22.813% (12.5700-31.7600%) for grade III. The mean MTR value was significantly different between each Pfirrmann grade: between grades I and II (p < 0.005), grades II and III (p < 0.05), and grades I and III (p < 0.005). There was a significant moderate positive correlation between Pfirrmann grading and mean MTR values (r = 0.516). Conclusion: The magnetization transfer ratio seems to be an objective method to detect early intervertebral disk degeneration via quantitative analysis.
RESUMO
A 5.5-year-old spayed female cane corso dog was presented for recurrent hematuria and dysuria. Abdominal ultrasound demonstrated severe hypoechoic urinary bladder wall thickening with irregular mucosal surface and polypoid-like lesions protruding into the lumen, abdominal polyadenomegaly, and splenic honeycombing. High-grade lymphoma was diagnosed on urinary bladder wall cytology. Clinical signs and ultrasonographic findings initially improved following a modified CHOP-based chemotherapy protocol, but the multicentric lymphoma then progressed with thoracic spread, leading to the dog's death at 9 wk post-diagnosis. Key clinical message: This case report describes the ultrasonographic features of malignant lymphomatous infiltration of the urinary bladder and emphasizes the importance of including lymphoma in the differential diagnosis for parietal urinary bladder lesions. It also describes the endoscopic findings of such an infiltration that have not yet, to the authors' knowledge, been described or illustrated in the veterinary literature. Finally, this case report underlines the poor prognosis of multicentric lymphoma involving the urinary bladder, with rapid progression of the disease and short survival time despite chemotherapy.
Résultats échographiques d'un lymphome malin multicentrique impliquant la vessie chez un chien: diagnostic et surveillance pendant la chimiothérapie. Une chienne cane corso stérilisée âgée de 5,5 ans a été présentée pour une hématurie et une dysurie récurrentes. L'échographie abdominale a démontré un épaississement hypoéchogène sévère de la paroi de la vessie avec une surface muqueuse irrégulière et des lésions de type polypoïde faisant saillie dans la lumière, une polyadénomégalie abdominale et une rate avec apparence en nid d'abeille. Un lymphome de grade élevé a été diagnostiqué sur la base de la cytologie de la paroi de la vessie. Les signes cliniques et les résultats échographiques se sont initialement améliorés après un protocole de chimiothérapie à base de CHOP modifié, mais le lymphome multicentrique a ensuite progressé avec une propagation thoracique, entraînant la mort du chien à 9 semaines après le diagnostic.Message clinique clé:Ce rapport de cas décrit les caractéristiques échographiques de l'infiltration lymphomateuse maligne de la vessie et souligne l'importance d'inclure le lymphome dans le diagnostic différentiel des lésions pariétales de la vessie. Il décrit également les résultats endoscopiques d'une telle infiltration qui n'ont pas encore, à la connaissance des auteurs, été décrits ou illustrés dans la littérature vétérinaire. Enfin, ce rapport de cas souligne le mauvais pronostic du lymphome multicentrique impliquant la vessie, avec une progression rapide de la maladie et une courte durée de survie malgré la chimiothérapie.(Traduit par Dr Serge Messier).