RT Journal Article SR Electronic T1 Dinosaur tail sign on spinal MRI in a patient with postdural puncture headache JF BMJ Case Reports FD BMJ Publishing Group Ltd SP bcr-2017-221447 DO 10.1136/bcr-2017-221447 VO 2017 A1 Keita Sakurai A1 Satoru Morimoto A1 Masashi Kameyama A1 Mitsuhito Mase YR 2017 UL http://casereports.bmj.com/content/2017/bcr-2017-221447.abstract AB