Non-contrast-Enhanced Functional Lung MRI to evaluate treatment response of allergic bronchopulmonary aspergillosis in patients with cystic fibrosis: a pilot study

Abstract

AbstractBackgroundAllergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) patients is associated with severe lung damage and requires specific therapeutic management. Repeated imaging is recommended to both diagnose and follow-up the response to treatment of ABPA in CF.PurposeTo evaluate whether Fourier decomposition (FD) functional lung MRI can detect the response to treatment of ABPA in CF patients.Study typeRetrospective longitudinal.PopulationA total of 12 CF patients.Field strength/sequence2D balanced steady-state free precession (bSSFP) sequence with Fourier decomposition (FD) at 1.5T scanner.AssessmentVentilation weighted (V) and perfusion weighted (Q) maps were obtained after FD processing of the 2D coronal bSSFP time resolved images before and after treatment of ABPA. Defects extent was assessed on the functional maps using a visual semi quantitative score. Mean and coefficient of variation (cv) of the ventilation signal intensity (VSI) and the perfusion signal intensity (QSI) were calculated. Measurements were performed independently by two readers and averaged. The reproducibility of the measurements was also assessed. Pulmonary function tests (PFTs) were performed as markers of the airflow limitation severity.Statistical testsComparisons of medians were assessed using paired Wilcoxon test. Reproducibility was assessed using the intraclass correlation coefficient (ICC). Correlations were assessed using Spearman test. A p value <0.05 was considered as significant.ResultsDefects extent on both V and Q maps showed a significant reduction after ABPA treatment (p<0.01). VSI_mean was significantly increased after treatment (p<0.01). Visual analyses reproducibility showed an ICC >0.93. ICC of the quantitative measurements was almost perfect (>0.99). VSI_cv and QSI_cv variations correlated inversely with the variation of obstructive parameters of PFTs (rho = -0.68, p=0.01).Data conclusionNon-contrast enhanced FD lung MRI appears to be able to reproducibly assess response to treatment of ABPA in CF patients and correlates with PFTs’ obstructive parameters.