Magnetic Resonance Imaging (Mri) Of The Spine In Small Animals— Evaluation Of Sequences And Protocol Recommendations

Fonseca Pinto AC, Hecht S.

American College of Veterinary Radiologists 2012:106.

Introduction/Purpose: Magnetic resonance imaging (MRI) is the gold standard in 2 of the evaluation of the nervous system in humans and is increasingly utilized in veterinary medicine. To minimize overall examination time attempts have been made in human medicine to develop MRI protocols with a limited number of specific sequences. The same would be desirable for veterinary medicine. The goal of this research was to determine the most useful MRI sequences to evaluate the spine of dogs in light of clinical findings.

Methods: A retrospective evaluation of 122 MRI studies was performed by two investigators, and a consensus was reached in order to select the 2 sequences that were most helpful in the identification and classification of spinal lesions. Sequences SV e evaluated included sagittal T1 -W SE, T2-W FSE, STIR, and when available T2*-W at e and post contrast T1 -W SE with fat saturation (FS). Signalment, history, reason for or I MR examination and final diagnosis/outcome were recorded for each patient. The studies were divided in three groups according to the onset of signs [acute (AC) 6 – ur y l 24h, subacute (SBA) 24h – 1 week and chronic (CR) > 1 week].

Results: The most common breeds in our study population were Dachshund and Labrador Retriever. There was no obvious age or sex predilection. 17.2% of dogs ,were in the AC group, 15.6% in the SBA group, and the majority (67.2%) in the CR group. The most common clinical sign regardless of group assignment was pain.Loss of the deep pain was more frequent in the AC group. The most frequent finding 5K in each group was extradural lesions (AC 71.4%; SBA 68.4%; CR 61.0). MRI sequences considered most useful for each group was STIR followed by T2-W in all groups. T2-W and post contrast I l – W sequences showed increasing importance in chronic cases.

Discussion/Conclusion: Based on our study results choice of MRI sequences for T evaluation of the canine spine should include the STIR sequence regardless of Nduration of clinical signs. In patients with chronic signs acquisition of post contrast Tl-W images should also be considered.