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Echo Time‐Dependence of Observed Lung T 1 in Patients With Cystic Fibrosis and Correlation With Clinical Metrics
Author(s) -
Triphan Simon M.F.,
Stahl Mirjam,
Jobst Bertram J.,
Sommerburg Olaf,
Kauczor HansUlrich,
Schenk JensPeter,
Alrajab Abdulsattar,
Eichinger Monika,
Mall Marcus A.,
Wielpütz Mark O.
Publication year - 2020
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.27271
Subject(s) - medicine , cystic fibrosis , lung , nuclear medicine , spirometry , correlation , perfusion , population , radiology , mathematics , geometry , environmental health , asthma
Background Noninvasive monitoring of early abnormalities and therapeutic intervention in cystic fibrosis (CF) lung disease using MRI is important. Lung T 1 mapping has shown potential for local functional imaging without contrast material. Recently, it was discovered that observed lung T 1 depends on the measurement echo time (TE). Purpose To examine TE‐dependence of observed T 1 in patients with CF and its correlation with clinical metrics. Study Type Prospective. Population In all, 75 pediatric patients with CF (8.6 ± 6.1 years, range 0.1–23 years), with 32 reexamined after 1 year. Field Strength/Sequence Patients were examined at 1.5T using an established MRI protocol and a multiecho inversion recovery 2D ultrashort echo time (UTE) sequence for T 1 (TE) mapping at five TEs including TE 1 = 70 μs. Assessment Morphological and perfusion MRI were assessed by a radiologist (M.W.) with 11 years of experience using an established CF‐MRI scoring system. T 1 (TE) was quantified automatically. Clinical data including spirometry (FEV1pred%) and lung clearance index (LCI) were collected. Statistical Tests T 1 (TE) was correlated with the CF‐MRI score, clinical data, and LCI. Results T 1 (TE) showed a different curvature in CF than in healthy adults: T 1 at TE 1 was shorter in CF (1157 ms ± 73 ms vs. 1047 ms ± 70 ms, P < 0.001), but longer at TE 3 (1214 ms ± 72 ms vs. 1314 ms ± 68 ms, P < 0.001) and later TEs. The correlations of T 1 (TE) with patient age (ρ TE1‐TE5 = −0.55, −0.44, −0.24, −0.30, −0.22), and LCI (ρ TE1‐TE5 = −0.43, −0.42, −0.33, 0.27, −0.22) were moderate at ultra‐short to short TE ( P < 0.001) but decreased for longer TE. Moderate but similar correlations at all TE were found with MRI perfusion score (ρ TE1‐TE5 = −0.43, −0.51, −0.47, −0.46, −0.44) and FEV1pred% (ρ TE1‐TE5 = +0.44, +0.44, +0.43, +0.40, +0.39) ( P < 0.05). Data Conclusion TE should be considered when measuring lung T 1 , since observed differences between CF and healthy subjects strongly depend on TE. The different variation of correlation coefficients with TE for structural vs. functional metrics implies that TE‐dependence holds additional information which may help to discern effects of tissue structural abnormalities and abnormal perfusion. Level of Evidence 2 Technical Efficacy Stage 1 J. MAGN. RESON. IMAGING 2020;52:1645–1654.