The impact of susceptibility correction on diffusion metrics in adolescents

Katri Lahti ,Jere Jaakkola ,Karoliina Uusitalo ,Eveliina Joensuu ,Leena Haataja,Petriina Munck ,Hanna E Manninen ,Max Karukivi ,Annika Lind ,Anna Nyman ,Päivi Tuomikoski-Koiranen ,Jonna Maunu ,Linda Grönroos ,Suvi Stolt ,Tiina Saarinen ,Mari Koivisto ,Marika Leppänen ,Mira Mattson ,Pertti Palo ,Mira Huhtala ,Sirkku Setänen ,Riitta Parkkola,Liisa Lehtonen ,Päivi Jääsaari ,Helena Lapinleimu ,Anniina Väliaho ,Eeva Ekholm ,Liisi Ripatti ,Katriina Saarinen ,Pentti Kero ,Pekka Niemi ,Satu Ekblad ,Päivi Rautava ,Matti Sillanpää ,Annarilla Ahtola ,Mikael Ekblad ,Timo Tuovinen ,Laura Määttänen ,Tuomo Lehtonen ,Riikka Korja ,Milla Ylijoki ,Virva Saunavaara

doi:10.1007/s00247-021-05000-3

Abstract

BackgroundDiffusion tensor imaging is a widely used imaging method of brain white matter, but it is prone to imaging artifacts. The data corrections can affect the measured values.ObjectiveTo explore the impact of susceptibility correction on diffusion metrics.Materials and methodsA cohort of 27 healthy adolescents (18 boys, 9 girls, mean age 12.7 years) underwent 3-T MRI, and we collected two diffusion data sets (anterior–posterior). The data were processed both with and without susceptibility artifact correction. We derived fractional anisotropy, mean diffusivity and histogram data of fiber length distribution from both the corrected and uncorrected data, which were collected from the corpus callosum, corticospinal tract and cingulum bilaterally.ResultsFractional anisotropy and mean diffusivity values significantly differed when comparing the pathways in all measured tracts. The fractional anisotropy values were lower and the mean diffusivity values higher in the susceptibility-corrected data than in the uncorrected data. We found a significant difference in total tract length in the corpus callosum and the corticospinal tract.ConclusionThis study indicates that susceptibility correction has a significant effect on measured fractional anisotropy, and on mean diffusivity values and tract lengths. To receive reliable and comparable results, the correction should be used systematically.

Highlights

Diffusion tensor imaging and diffusion-tensor-based tractography are used in modern neuroscience to study brain white matter [1,2,3]
The diffusion properties of white matter are affected by myelination and axonal features, for example, but the metrics are influenced by the tract volume and iron and water content inside a voxel [3, 7]
The P-values for the corpus callosum, corticospinal tract, right cingulum and left cingulum were ≤0.001 for both diffusion metrics

Summary

Introduction

Diffusion tensor imaging and diffusion-tensor-based tractography are used in modern neuroscience to study brain white matter [1,2,3]. Diffusion tensor imaging is prone to image artifacts such as distortion, signal loss and blurring, Nyquist ghosts and chemical shift artifacts. Image distortions and signal loss are caused by magnetic susceptibility variations, eddy currents, B0-field inhomogeneities and concomitant magnetic field artifacts [8]. Eddy current artifacts are the most widely studied, but susceptibility artifacts are known to affect imaging protocols [9, 10]. Diffusion tensor imaging is a widely used imaging method of brain white matter, but it is prone to imaging artifacts.

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Discussion

Conclusion