D. Zamboni comments on Pub Med in reference to the methodology used by Traboulsee et.al to measure jugular venous obstruction
http://www.ncbi.nlm.nih.gov/pubmed/24119384#cm24119384_8458


Prevalence of extracranial venous narrowing on catheter venography ... - PubMed - NCBI
www.ncbi.nlm.nih.gov
Lancet. 2014 Jan 11;383(9912):138-45. doi: 10.1016/S0140-6736(13)61747-X. Epub 2013 Oct 9. Multicenter Study; Research Support, Non-U.S. Gov't