Decrease of pulmonary blood flow detected by phase contrast MRI is correlated with a decrease in lung volume and increase of lung fibrosis area determined by computed tomography in interstitial lung disease

PurposeLung volume and pulmonary blood flow decrease in patients with interstitial lung disease (ILD). The purpose of this study was to assess the relationship between pulmonary blood flow and lung volume in ILD patients.MethodsThis research was approved by the institutional review board.Twenty-seven patients (9 men, 18 women; mean age, 59 years; range, 24-79 years) with ILD were included. Blood flow was assessed in the pulmonary trunk and the left and right pulmonary arteries by phase contrast magnetic resonance imaging (MRI). Lung volume and the computed tomography (CT) visual score that indicates the severity of ILD were assessed on the left and right sides by thin-section CT scanning. Lung volume was automatically measured by lung analysis software (VINCENT Ver. 4). The CT visual score was measured by averaging the proportion of abnormal lung area at five anatomic levels. Pearson's correlation coefficient was used to determine the relationship between pulmonary blood flow and lung volume.ResultsPulmonary blood flow showed a significant correlation with lung volume (both: r = 0.52, p = 0.006; left: r = 0.61, p = 0.001; right: r = 0.54, p = 0.004) and CT visual score (both: r = −0.39, p = 0.04; left: r = −0.48, p = 0.01; right: r = −0.38, p = 0.04). Partial correlation analysis, controlled for age, height and weight, showed a significant correlation between pulmonary blood flow and lung volume (both: r = 0.43, p = 0.03; left: r = 0.55, p = 0.005; right: r = 0.48, p = 0.01) and CT visual score (both: r = −0.58, p = 0.003; left: r = −0.51, p = 0.01; right: r = −0.64, p = 0.001).ConclusionIn ILD, reduced pulmonary blood flow is associated with reduced lung volume and increased abnormal lung area.