Algorithm for fast monoexponential fitting based on Auto-Regression on Linear Operations (ARLO) of data

• Published in: Magnetic resonance in medicine Vol. 73; no. 2; pp. 843 - 850
• Main Authors: Pei, Mengchao, Nguyen, Thanh D., Thimmappa, Nanda D., Salustri, Carlo, Dong, Fang, Cooper, Mitch A., Li, Jianqi, Prince, Martin R., Wang, Yi
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.02.2015; Wiley Subscription Services, Inc
• Subjects: Adult; Algorithms; autoregression; Brain - pathology; Computer Simulation; Female; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; iron overload; Levenberg-Marquardt; Linear Models; Log-Linear; Male; Numerical Analysis, Computer-Assisted; Regression Analysis; Reproducibility of Results; Sensitivity and Specificity; T2 mapping; Levenberg-Marquardt; Log-Linear; iron overload; autoregression; T2 mapping
• ISSN: 0740-3194; 1522-2594; 1522-2594
• DOI: 10.1002/mrm.25137

Purpose To develop a fast and accurate monoexponential fitting algorithm based on Auto‐Regression on Linear Operations (ARLO) of data, and to validate its accuracy and computational speed by comparing it with the conventional Levenberg‐Marquardt (LM) and Log‐Linear (LL) algorithms. Methods ARLO, LM, and LL performances for T2* mapping were evaluated in simulation and in vivo imaging of liver (n = 15) and myocardial (n = 1) iron overload patients and the brain (two healthy volunteers). Results In simulations, ARLO consistently delivered accuracy similar to LM and significantly superior to LL. In in vivo mapping of T2* values, ARLO showed excellent agreement with LM, while LL showed only limited agreements with ARLO and LM. Compared with LM and LL in the liver, ARLO was 125 and 8 times faster using our Matlab implementations, and 156 and 13 times faster using our C++ implementations. In C++ implementations, ARLO reduced the online whole‐brain processing time from 9 min 15 s of LM and 35 s of LL to 2.7 s, providing T2* maps approximately in real time. Conclusion Due to comparable accuracy and significantly higher speed, ARLO can be considered as a valid alternative to the conventional LM algorithm for online T2* mapping. Magn Reson Med 73:843–850, 2015. © 2014 Wiley Periodicals, Inc.