The NHLBI recently provided funding for a clinical trial targeting the excess inflammation in HIV. The "Parent Study" is being performed as a collaboration with the National Institute of Allergy and Infectious Diseases (NIAID) AIDS Clinical Trials Group and the NHLBI. That randomized, double-blind, placebo-controlled trial will assess whether 24-week treatment with very low-dose methotrexate (LDMTX): i) is safe, ii) reduces levels of circulating inflammatory biomarkers and activated immune cells and iii) improves brachial artery reactivity (BART). However, neither the biomarkers nor the BART studies measured as part of Parent Study will report on atherosclerotic inflammation, (the desired pathobiological target of LDMTX therapy in HIV). As such, the direct evaluation of arterial inflammation would substantially enhance the scientific value of the Parent Study.