Validation of Phase-Resolved Functional Lung (PREFUL) Magnetic Resonance Imaging Pulse Wave Transit Time Compared to Echocardiography in Chronic Obstructive Pulmonary Disease.

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Phase-resolved functional lung (PREFUL) magnetic resonance imaging (MRI) pulmonary pulse wave transit time (pPTT) is a contrast agent free, vascular imaging biomarker, but has not been validated in chronic obstructive pulmonary disease (COPD). To validate PREFUL with echocardiographic pPTT as a reference standard and to compare arterial/venous pPTT mapping with spirometry and clinical parameters. Prospective. Twenty-one patients (62% female) with COPD and 44 healthy participants (50% female). 1.5 T; 2D-spoiled gradient-echo sequence. Three coronal PREFUL MRI slices, echocardiography, and spirometry including forced expiratory volume in 1 second (FEV1, liter) and predicted defined as FEV1 in% divided by the population average FEV1%, were performed. Pulmonary pulse transit time from the main artery to the microvasculature (PREFUL pPTT), to the right upper lobe vein (PREFUL pPTTav , echo pPTTav ), from microvasculature to right upper lobe vein (PREFULvein ) and the ratio of PREFUL pPTT to PREFUL pPTTvein were calculated. Body mass index (BMI), Global Initiative for COPD (GOLD) stage 1-4, disease duration, and cigarette packs smoked per day multiplied by the smoked years (pack years) were computed. Shapiro-Wilk-test, paired-two-sided-t-tests, Bland-Altman-analysis, coefficient of variation, Pearson ρ were applied, pPTT data were compared between 21 subjects from the 44 healthy subjects who were age- and sex-matched to the COPD cohort, P < 0.05 was considered statistically significant. PREFUL pPTTav significantly correlated with echo pPTTav (ρ=0.95) with 1.85 msec bias, 95% limits of agreement: 55.94 msec, -52.23 msec in all participants (P=0.59). In the healthy participants, PREFUL and echo pPTTav significantly correlated with age (ρ=0.81, ρ=0.78), FEV1 (ρ=-0.47, ρ=-0.34) and BMI (ρ=0.56, ρ=0.51). In COPD patients, PREFUL pPTT significantly correlated with FEV1 predicted (ρ=-0.59), GOLD (ρ=0.53), disease duration (ρ=0.54), and pack years (ρ=0.49). Arteriovenous PTT measured by PREFUL MRI corresponds precisely to echocardiography and appears to be feasible even in severe COPD. 1 TECHNICAL EFFICACY: Stage 2.