T1-weighted Dynamic Contrast-enhanced MR Imaging of the Lung in Asthma: Semiquantitative Analysis for the Assessment of Contrast Agent Kinetic Characteristics.
OBJECTIVE
To evaluate the contrast agent kinetics of dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging in healthy lungs and asthmatic lungs by using non-model-based semiquantitative parameters and to explore the relationships with pulmonary function testing and eosinophil level.


METHODS
The study was approved by the National Research Ethical Committee (reference no. 11/NW/0387), and written informed consent was obtained from all individuals. Ten healthy subjects and 30 patients with asthma underwent pulmonary function tests, blood and sputum eosinophil counts, and 1.5-T DCE MR imaging within 7 days. Semiquantitative parameters of contrast agent kinetics were calculated from the relative signal intensity-time course curves on a pixel-by-pixel basis and were summarized by using whole-lung median values. The distribution heterogeneity was assessed by using the regional coefficient of variation. DCE MR imaging readouts were compared between groups by using one-way analysis of variance, and the relationships with pulmonary function testing and eosinophil counts were assessed by using Pearson correlation analysis.


RESULTS
Asthmatic patients showed significantly lower peak enhancement (P < .001) and initial areas under the relative signal intensity curve in the first 60 seconds (P = .002) and significantly reduced late-phase washout slope (P = .002) when compared with healthy control subjects. The distribution heterogeneity of bolus arrival time (P = .029), time to peak (P = .008), upslope of the first-pass peak (P = .011), and late-phase washout slope (P = .032), estimated by using the median coefficient of variation, were significantly higher in asthmatic patients than in healthy control subjects. These imaging readouts also showed significant linear correlations with measurements of pulmonary function testing but not with eosinophil level in patients with asthma.


CONCLUSIONS
The contrast agent kinetic characteristics of T1-weighted DCE MR images of asthmatic lungs are different from those of healthy lungs and are related to measurements of pulmonary function testing but not to eosinophil level.
From the Centre for Imaging Sciences (W.J.Z., G.J.M.P., J.H.N.) and Biomedical Imaging Institute (W.J.Z., G.J.M.P., J.H.N.), the University of Manchester, Oxford Rd, Manchester M13 9PT, England; North West Lung Research Centre, University Hospital of South Manchester, Manchester, England (R.M.N.); Personalised Healthcare and Biomarkers, AstraZeneca R&D, Macclesfield, England (S.S.Y., Y.Z.L.); and Bioxydyn Limited, Manchester, England (G.J.M.P.).
Wei-Juan
WJ
Zhang
From the Centre for Imaging Sciences (W.J.Z., G.J.M.P., J.H.N.) and Biomedical Imaging Institute (W.J.Z., G.J.M.P., J.H.N.), the University of Manchester, Oxford Rd, Manchester M13 9PT, England; North West Lung Research Centre, University Hospital of South Manchester, Manchester, England (R.M.N.); Personalised Healthcare and Biomarkers, AstraZeneca R&D, Macclesfield, England (S.S.Y., Y.Z.L.); and Bioxydyn Limited, Manchester, England (G.J.M.P.).
Robert M
RM
Niven
From the Centre for Imaging Sciences (W.J.Z., G.J.M.P., J.H.N.) and Biomedical Imaging Institute (W.J.Z., G.J.M.P., J.H.N.), the University of Manchester, Oxford Rd, Manchester M13 9PT, England; North West Lung Research Centre, University Hospital of South Manchester, Manchester, England (R.M.N.); Personalised Healthcare and Biomarkers, AstraZeneca R&D, Macclesfield, England (S.S.Y., Y.Z.L.); and Bioxydyn Limited, Manchester, England (G.J.M.P.).
Simon S
SS
Young
From the Centre for Imaging Sciences (W.J.Z., G.J.M.P., J.H.N.) and Biomedical Imaging Institute (W.J.Z., G.J.M.P., J.H.N.), the University of Manchester, Oxford Rd, Manchester M13 9PT, England; North West Lung Research Centre, University Hospital of South Manchester, Manchester, England (R.M.N.); Personalised Healthcare and Biomarkers, AstraZeneca R&D, Macclesfield, England (S.S.Y., Y.Z.L.); and Bioxydyn Limited, Manchester, England (G.J.M.P.).
Yu-Zhen
YZ
Liu
From the Centre for Imaging Sciences (W.J.Z., G.J.M.P., J.H.N.) and Biomedical Imaging Institute (W.J.Z., G.J.M.P., J.H.N.), the University of Manchester, Oxford Rd, Manchester M13 9PT, England; North West Lung Research Centre, University Hospital of South Manchester, Manchester, England (R.M.N.); Personalised Healthcare and Biomarkers, AstraZeneca R&D, Macclesfield, England (S.S.Y., Y.Z.L.); and Bioxydyn Limited, Manchester, England (G.J.M.P.).
Geoffrey J M
GJ
Parker
From the Centre for Imaging Sciences (W.J.Z., G.J.M.P., J.H.N.) and Biomedical Imaging Institute (W.J.Z., G.J.M.P., J.H.N.), the University of Manchester, Oxford Rd, Manchester M13 9PT, England; North West Lung Research Centre, University Hospital of South Manchester, Manchester, England (R.M.N.); Personalised Healthcare and Biomarkers, AstraZeneca R&D, Macclesfield, England (S.S.Y., Y.Z.L.); and Bioxydyn Limited, Manchester, England (G.J.M.P.).
Josephine H
JH
Naish
D000328:Adult; D001249:Asthma / Q000473:pathology*; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008168:Lung / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000493:pharmacokinetics*; D008875:Middle Aged; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D012129:Respiratory Function Tests
D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine