title: Early detection of lung inflammation: exploiting T1-effects of iron oxide particles using UTE MRI.
abstract: At high magnetic fields diagnostic proton MRI of the lung is problematic, because of fast T2* relaxation. The application of superparamagnetic contrast agents and the exploitation of the corresponding T2* effect is inefficient with conventional MRI methods, which limits the early detection of lung diseases. However, a simple theoretical treatment shows that in the lung, by the use of ultra-short echo time sequences, T2* effects can be neglected while T(1) shortening effects can be used for signal detection. In our study, we have applied a theoretically and experimentally optimized 3D ultra-short echo time sequence to lung phantoms and to a mouse model of lung inflammation, which was induced by systemic bacterial infection. Following the systemic application of very small superparamagnetic iron oxide nanoparticles, a significant signal increase in the lung of infected animals was detected already at 24 h postinfection, compared to control mice (17%, P < 0.001). Iron accumulation in the lung parenchyma as consequence of the host immune response was histologically confirmed. By conventional T2*- and T(2)-weighted imaging, neither structural changes nor formation of substantial edema were observed.
authors.affiliation: Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Strobel
authors.forename: Verena
authors.initials: V
authors.lastname: Hoerr
authors.forename: Florian
authors.initials: F
authors.lastname: Schmid
authors.forename: Lydia
authors.initials: L
authors.lastname: Wachsmuth
authors.forename: Bettina
authors.initials: B
authors.lastname: Löffler
authors.forename: Cornelius
authors.initials: C
authors.lastname: Faber
mesh_terms: D000465:Algorithms; D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D042241:Early Diagnosis; D005260:Female; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D051379:Mice; D008810:Mice, Inbred C57BL; D011023:Pneumonia, Staphylococcal / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; C097921:ferumoxtran-10