Fig. 1.

Spinal cord MRI of a 20-year-old woman with a history of massive N₂O abuse who presented a sensory and motor impairment of the four limbs. T2-weighted image of the cervical cord at the axial level C2–6 shows an increased intensity of the posterior columns, predominating in the fasciculus gracilis (inverted V-sign, not shown). T1-weighted contrast-enhanced sagittal image shows a linear uptake of the lesion (upper image). The axial image supports the involvement of the fasciculus gracilis, while the fasciculus cuneatus at the posterior midline remains normal (lower inset).