This value set includes codes based on the following rules:

• Include these codes as defined in http://dicom.nema.org/resources/ontology/DCM

  Code	Display	Definition
  112077	Vasoconstriction	Local or general reduction in the caliber of visible pulmonary vessels, presumed to result from decreased flow occasioned by contraction of muscular pulmonary arteries [Fraser and Pare].
  112078	Vasodilation	Local or general increase in the width of visible pulmonary vessels resulting from increased pulmonary blood flow [Fraser and Pare].

• Include these codes as defined in http://snomed.info/sct

  Code	Display
  134223000	Narrow
  260376009	Enlarged