Non‐Contrast‐Enhanced Functional Lung MRI to Evaluate Treatment Response of Allergic Bronchopulmonary Aspergillosis in Patients With Cystic Fibrosis: A Pilot Study

Background Allergic 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 response to treatment of ABPA in CF. However, high risk of cumulative radiation exposure requires evaluation of free‐radiation techniques in the follow‐up of CF patients with ABPA. Purpose To evaluate whether Fourier decomposition (FD) functional lung MRI can detect response to treatment of ABPA in CF patients. Study Type Retrospective longitudinal. Population Twelve patients (7M, median‐age:14 years) with CF and ABPA with pre‐ and post‐treatment MRI. Field Strength/Sequence 2D‐balanced‐steady‐state free‐precession (bSSFP) sequence with FD at 1.5T. Assessment Ventilation‐weighted (V) and perfusion‐weighted (Q) maps were obtained after FD processing of 2D‐coronal bSSFP time‐resolved images acquired before and 3–9 months after treatment. Defects extent was assessed on the functional maps using a qualitative semi‐quantitative score (0 = absence/negligible, 1 = 50%). 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 three readers and averaged. Inter‐reader reproducibility of the measurements was assessed. Pulmonary function tests (PFTs) were performed within 1 week of both MRI studies as markers of the airflow‐limitation severity. Statistical Tests Comparisons of medians were performed using the paired Wilcoxon‐test. Reproducibility was assessed using intraclass correlation coefficient (ICC). Correlations between MRI and PFT parameters were assessed using the Spearman‐test (rho correlation‐coefficient). A P‐value 0.90, while the ICCs of the quantitative measurements was almost perfect (>0.99). Changes in VSI_cv and QSI_cv before and after treatment correlated inversely with changes of FEV1%p (rho = −0.68 for both). Data Conclusion Non‐contrast‐enhanced FD lung MRI has potential to reproducibly assess response to treatment of ABPA in CF patients and correlates with PF