Open AccessReproducibility and comparison of oxygen-enhanced T1 quantification in COPD and asthma patients
Author(s) -
Simon M. F. Triphan,
Bertram J. Jobst,
Angela Anjorin,
Oliver Sedlaczek,
Ursula Wolf,
Maxim Terekhov,
Christian Hoffmann,
Sebastian Ley,
Christoph Düber,
Jürgen Biederer,
HansUlrich Kauczor,
Peter M. Jakob,
Mark O. Wielpütz
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0172479
Subject(s) - copd , asthma , medicine , reproducibility , lung , chemistry , chromatography
T 1 maps have been shown to yield useful diagnostic information on lung function in patients with chronic obstructive pulmonary disease (COPD) and asthma, both for native T 1 and Δ T 1 , the relative reduction while breathing pure oxygen. As parameter quantification is particularly interesting for longitudinal studies, the purpose of this work was both to examine the reproducibility of lung T 1 mapping and to compare T 1 found in COPD and asthma patients using IRSnapShotFLASH embedded in a full MRI protocol. 12 asthma and 12 COPD patients (site 1) and further 15 COPD patients (site 2) were examined on two consecutive days. In each patient, T 1 maps were acquired in 8 single breath-hold slices, breathing first room air, then pure oxygen. Maps were partitioned into 12 regions each to calculate average values. In asthma patients, the average T 1, RA = 1206ms (room air) was reduced to T 1, O 2 = 1141ms under oxygen conditions (Δ T 1 = 5.3%, p < 5⋅10 −4 ), while in COPD patients both native T 1, RA = 1125ms was significantly shorter ( p < 10 −3 ) and the relative reduction to T 1, O 2 = 1081ms on average Δ T 1 = 4.2%( p < 10 −5 ). On the second day, with T 1, RA = 1186ms in asthma and T 1, RA = 1097ms in COPD, observed values were slightly shorter on average in all patient groups. Δ T 1 reduction was the least repeatable parameter and varied from day to day by up to 23% in individual asthma and 30% in COPD patients. While for both patient groups T 1 was below the values reported for healthy subjects, the T 1 and Δ T 1 found in asthmatics lies between that of the COPD group and reported values for healthy subjects, suggesting a higher blood volume fraction and better ventilation. However, it could be demonstrated that lung T 1 quantification is subject to notable inter-examination variability, which here can be attributed both to remaining contrast agent from the previous day and the increased dependency of lung T 1 on perfusion and thus current lung state.