Spondylolysis in an 8-year-old boy. Spondylolysis in an 8-year-old boy. A, Axial T2-weighted image with fat saturation demonstrates hyperintense signal intensity consistent with bone marrow edema in the region of the pars defects bilaterally. B, Axial CT image demonstrates a complete pars defect of L5 on the right. C, Axial CT image demonstrates an incomplete pars defect of L5 on the left. D.P. Rodriguez, and T.Y. Poussaint AJNR Am J Neuroradiol 2010;31:787-802 ©2010 by American Society of Neuroradiology