Pre- and posttreatment spine MRI in a patient with solid tumor leptomeningeal disease

(A [pretreatment]) Sagittal T1 postcontrast MRI in a patient with leptomeningeal disease showing nodular (arrowheads) and linear (arrows) enhancement in the cauda equina. (B [posttreatment]) Postradiation MRI showing some improvement in the degree of abnormal enhancement in the cauda equina.