Normalized T 1 Magnetic Resonance Imaging for Assessment of Regional Lung Function in Adult Cystic Fibrosis Patients-A Cross-Sectional Study

Background: Cystic fibrosis (CF) patients would benefit from a safe and effective tool to detect early-stage, regional lung disease to allow for early intervention. Magnetic Resonance Imaging (MRI) is a safe, non-invasive procedure capable of providing quantitative assessments of disease without ionizing radiation. We developed a rapid normalized T1 MRI technique to detect regional lung disease in early-stage CF patients. Materials and Methods: Conventional multislice, pulmonary T1 relaxation time maps were obtained for 10 adult CF patients with normal spirometry and 5 healthy non-CF control subjects using a rapid Look-Locker MRI acquisition (5 seconds/ imaging slice). Each lung absolute T1 map was separated into six regions of interest (ROI) by manually selecting upper, central, and lower lung regions in the left and right lungs. In order to reduce the effects of subject-to-subject variation, normalized T1 maps were calculated by dividing each pixel in the absolute T1 maps by the mean T1 time in the central lung region. The primary outcome was the differences in mean normalized T1 values in the upper lung regions between CF patients with normal spirometry and healthy volunteers. Results: Normalized T1 (nT1) maps showed visibly reduced subject-to-subject variation in comparison to conventional absolute T1 maps for healthy volunteers. An ROI analysis showed that the variation in the nT1 values in all regions was #2% of the mean. The primary outcome, the mean (SD) of the normalized T1 values in the upper right lung regions, was significantly lower in the CF subjects [. 914 (.037)] compared to the upper right lung regions of the healthy subjects [. 983 (.003)] [difference of . 069 (95% confidence interval .0322.105); p = . 001). Similar results were seen in the upper left lung region. Conclusion: Rapid normalized T1 MRI relaxometry obtained in 5 seconds/imaging slice may be used to detect regional early-stage lung disease in CF patients. Citation: Dasenbrook EC, Lu L, Donnola S, Weaver DE, Gulani V, et al. (2013) Normalized T1 Magnetic Resonance Imaging for Assessment of Regional Lung Function in Adult Cystic Fibrosis Patients A Cross-Sectional Study. PLoS ONE 8(9): e73286. doi:10.1371/journal.pone. 0073286 Editor: Amit Gaggar, University of Alabama-Birmingham, United States of America Received April 13, 2013; Accepted July 18, 2013; Published September 25, 2013 Copyright: 2013 Dasenbrook et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported in part by National Institutes of Health (NIH) grants P30-DK027651 and CTSA-UL1TR000439, the Cystic Fibrosis Foundation (DASENB10A0 and KONSTA03Y2), and Seimens Medical System. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: Dr. Flask received technical support from Siemens Medical Systems. The authors declare that this relationship does not alter their adherence to all the PLOS ONE policies on sharing data and materials. * E-mail: ecd28@case.edu . These authors contributed equally to this work.