title: A linear algorithm of the reference region model for DCE-MRI is robust and relaxes requirements for temporal resolution.
abstract: Dynamic contrast enhanced MRI (DCE-MRI) has utility for improving clinical diagnoses of solid tumors, and for evaluating the early responses of anti-angiogenic chemotherapies. The Reference Region Model (RRM) can improve the clinical implementation of DCE-MRI by substituting the contrast enhancement of muscle for the Arterial Input Function that is used in traditional DCE-MRI methodologies. The RRM is typically fitted to experimental results with a non-linear least squares algorithm. This report demonstrates that this algorithm produces inaccurate and imprecise results when DCE-MRI results have low SNR or slow temporal resolution. To overcome this limitation, a linear least-squares algorithm has been derived for the Reference Region Model. This new algorithm improves accuracy and precision of fitting the Reference Region Model to DCE-MRI results, especially for voxel-wise analyses. This linear algorithm is insensitive to injection speeds, and has 300- to 8000-fold faster calculation speed relative to the non-linear algorithm. The linear algorithm produces more accurate results for over a wider range of permeabilities and blood volumes of tumor vasculature. This new algorithm, termed the Linear Reference Region Model, has strong potential to improve clinical DCE-MRI evaluations.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA.
authors.forename: Julio
authors.initials: J
authors.lastname: Cárdenas-Rodríguez
authors.forename: Christine M
authors.initials: CM
authors.lastname: Howison
authors.forename: Mark D
authors.initials: MD
authors.lastname: Pagel
mesh_terms: D000465:Algorithms; D000818:Animals; D045744:Cell Line, Tumor; D003198:Computer Simulation; D005260:Female; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D016513:Mice, SCID; D009374:Neoplasms, Experimental / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity