Stratification of risk for emergent intracranial abnormalities in children with headaches: a Pediatric Emergency Care Applied Research Network (PECARN) study protocol.

Tsze DS, Kuppermann N, Casper TC, Barney BJ, Richer LP, Liberman DB, Okada PJ, Morris CR, Myers SR, Soung JK, Mistry RD, Babcock L, Spencer SP, Johnson MD, Klein EJ, Quayle KS, Steele DW, Cruz AT, Rogers AJ, Thomas DG, Grupp-Phelan JM, Johnson TJ, Dayan PS, Pediatric Emergency Care Applied Research Network (PECARN)