My daughters mri reads numerous dilated loops throughout abd with a dilation to her rectum of 6.7cm. she started vomiting today. is this something i should take her to the ed for or wait until the 17th when she has her dr. appointment?

If vomiting is a new symptom and she has dilated loops of bowel, she should be evaluated as soon as possible. You should first call your pediatrician.

You should definitely take her to the hospital Emergency Department for further evaluation and management of her present status and stability if these are new or worsening findings. Enterocolitis as a late complication of Hirschprung Disease is definitely something that they or the gastroenterologists should rule in or out.