Simple Linear Regression Model Is Misleading When Used to Analyze Quantitative Diffusion Tensor Imaging Data That Include Young and Old Adults

K.M Hasan

doi:10.3174/ajnr.a2184

Abstract

I read with interest a recent article published in this journal by Wang et al.[1][1] The authors analyzed diffusion tensor imaging (DTI) data acquired on 71 healthy young, old, and older adult brains a (20–79 years of age). The authors calculated diffusion tensor metrics such as fractional

Highlights

The increase in striatal FA with age as reported by Wang et al is an important finding that confirms previous and recent DTI reports on both healthy children[2,3] and young[3,4] and older adults,[5,6,7,8,9] or across the human lifespan.[10]
While a trend in striatal increase in FA versus age reported by Wang et al is consistent with several reports using different DTI analysis methods,[2,3,4,5,6,7,8,9,10,11] I should point out that the finding of reduced mean diffusivity with age is contradictory to several previous reports that compared healthy young and older adults
I conclude that DTI quantitative reports with a relatively small population and sparse attenuation and extended age ranges should not use simple linear regression because this simple model fails to accommodate the expected decrease in diffusivity in children and the predicted rise in diffusivity as a result of increased water extracellular mobility as tissue ages.[11,12,13]

Summary

Introduction

The increase in striatal FA with age as reported by Wang et al is an important finding that confirms previous and recent DTI reports on both healthy children[2,3] and young[3,4] and older adults,[5,6,7,8,9] or across the human lifespan.[10].

Results

Conclusion