Objectives: To compare the value of different magnetic resonance sequences in the detection of brain lesions in dogs with multi-focal intracranial neurolocalised lesions and abnormal cisternal cerebrospinal fluid analysis.
Methods: T2-weighted, T1-weighted, T1-weighted-Gd, FLAIR (fluid attenuated inversion recovery) images of 73 dogs with multi-focal intracranial localised lesions were reviewed retrospectively. Control dogs (19) were selected on the basis of normal neurological examination, magnetic resonance images and cerebrospinal fluid analysis. Two board-certified radiologists blindly reviewed the magnetic resonance images. Magnetic resonance sequence sensitivities were compared using the chi-squared test and logistic regression, accounting for clustering at the patient level. Statistical significance was set at the 5 per cent level.
Results: The FLAIR sequence was found to have the highest sensitivity (84 per cent, 61 of 73), followed by T2-weighted (63 per cent, 46 of 73), T1-weighted postcontrast (62 per cent, 45 of 73) and T1-weighted (23 per cent, 17 of 73) (P<0·001). FLAIR images were 106·1 times (95 per cent confidence interval 25·2 to 447·5) more likely to correctly identify cerebrospinal fluid-positive patients than T1-weighted, 6·4 times (95 per cent confidence interval 2·2 to 18·2) than T1-weighted postcontrast and 5·8 times (95 per cent confidence interval 2·0 to 16·4) than T2-weighted. FLAIR identified 14 per cent of cases that were classified as normal based on the three others sequences.
Clinical Significance: Routine use of FLAIR sequence should be encouraged in dogs undergoing a brain magnetic resonance imaging and probably more specifically in cases of suspected inflammatory brain disease.