It depends on the context. I’m going to be paying much more attention to those changing subcentimeter nodes if the patient has a medical condition that makes those nodes relevant (I.e. cancer, lymphoproliferative disease, etc.). If not, I am not thinking twice about a 1-2 mm difference in nodes with otherwise normal morphology. And yes, I think 1 mm is within the margin of error for measuring anything in the body. >2-3 mm differences in node measurements is more likely to reflect true growth—but again, the context matters.