These tests can include Ventilation / perfusion scanning or CT angiography to detect thromboembolic disease HRCT for detailed information about lung parenchymal disorders in patients in whom CT angiography is not done Pulmonary function tests to identify obstructive or restrictive lung disease Serum autoantibody tests (eg, antinuclear antibodies [ANA], rheumatoid factor [RF], Scl-70 [topoisomerase I], anti-Ro (anti-SSA), anti-ribonucleoprotein [anti-RNP], and anticentromere antibodies) to gather evidence for or against associated autoimmune disorders Chronic thromboembolic pulmonary hypertension is suggested by CT angiography or ventilation / perfusion (VQ) scan findings and is confirmed by arteriography.