Correlation of intima plus media fractional thickness in patients with pulmonary arterial hypertension (PAH) with (A) mean pulmonary arterial pressure (mPAP) (n = 62, P = 0.066, R = 0.235), and (B) pulmonary vascular resistance (PVR) (n = 60, P = 0.057, R = 0.247). Correlation of media fractional thickness in patients with PAH with (C) mPAP (n = 62, P = 0.036, R = 0.267), and (D) PVR (n = 60, P = 0.047, R = 0.258).