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T 1 in high‐grade glioma and the influence of different measurement strategies on parameter estimations in DCE‐MRI
Author(s) -
Larsson Christopher,
Kleppestø Magne,
Grothe Inge,
Vardal Jonas,
Bjørnerud Atle
Publication year - 2015
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.24772
Subject(s) - histogram , mathematics , standard deviation , nuclear medicine , correlation , kinetic energy , pixel , medicine , statistics , computer science , physics , artificial intelligence , image (mathematics) , geometry , quantum mechanics
Background To investigate the evolution of T 1 in tumor and the necessity of baseline T 1 (T 1 (0)) mapping for the accurate estimation of kinetic parameters during standard therapy using dynamic contrast enhanced (DCE) MRI in patients with high‐grade glioma (HGG). Methods Longitudinal DCE‐MRI was performed in 23 patients (196 scans) with confirmed HGG. Kinetic parameters were derived from the extended Tofts model and analyzed both using fixed and pixel‐wise T 1 (0) values estimated from a Look‐Locker sequence. Median tumor T 1 value from all scans was used for fixed T 1 (0) analysis. Dependence of accurate T 1 (0) mapping for the estimation of the kinetic parameters was further investigated through computer simulations and histogram analysis. Results T 1 in tumor increased significantly during and after treatment ( P < 0.001). There was a linear correlation between the error in 1/T 1 (0) and the resulting error in estimated parameters in both simulations and clinical data (r 2 >0.98 for all parameters). A strong correlation between the estimated longitudinal change in all kinetic parameters obtained using pixel‐wise and fixed T 1 (0) was observed (r 2 > 0.84 for all parameters). Histogram analysis revealed a linear change (r 2 > 0.62) in K trans normalized histogram peak height ratio as function of percentage deviation from the nominal T 1 (0) value. No effect of T 1 (0) histogram distribution on K trans was observed ( P = 0.52). Conclusion Temporal changes in the median kinetic parameters in tumor were equally well described using pixel‐wise and fixed T 1 (0) despite an increase in T 1 (0) over time, suggesting that T 1 mapping is not generally required in DCE‐MRI based monitoring of glioma patients. J. Magn. Reson. Imaging 2015;42:97–104 . © 2014 Wiley Periodicals, Inc .