MRI of dogs thoracolumbar segment. In (A) the pre treatment the animals showed severe extradural compressive myelopathy ventrolateral between T11-T12 and disc protrusion at L3-L4, disc degeneration and spondylosis multifocal in thoracic and lumbar spine. In (B) after treatment the animal showed the same diagnosis at MRI without regression or progression of the previous reported. In (C) homogeneous hyperintensity maintained between T9-L2, extradural compressive myelopathy, mild to moderate between T12-T13, previous surgical procedure between T11-T13, with secondary muscle atrophy, disc dehydration multifocal in thoracolumbar spine were observed. In (D) after the treatment the same alterations were observed in the MRI. In (E) myelopathy extradural compressive between T9-T120 and T13-L1, with the presence of secondary siringohidromielia. In (F) after treatment probable thoracolumbar muscular atrophy with presence of siringohidromielia between T12-L1 and L3, and severe at T13-L1, multifocal disc dehydration in thoracolumbar spine.