RT Journal Article SR Electronic T1 Is There a Need for Contrast Administration Prior to CT-Guided Cervical Nerve Root Block? JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP E45 OP E45 DO 10.3174/ajnr.A3544 VO 34 IS 4 A1 Ryan, T.M. A1 Kavanagh, E.C. A1 MacMahon, P.J. YR 2013 UL http://www.ajnr.org/content/34/4/E45.abstract AB