Optimizing the accuracy of cortical volumetric analysis in traumatic brain injury

Bram R Diamond,Christine L Mac Donald,Aina Frau-Pascual,Samuel B Snider,Bruce Fischl,Kristen Dams-O'Connor,Brian L Edlow

doi:10.1016/j.mex.2020.100994

Bram R Diamond, Christine L Mac Donald + Show 5 more

Open Access

https://doi.org/10.1016/j.mex.2020.100994

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Abstract

Cortical volumetric analysis is widely used to study the anatomic basis of neurological deficits in patients with traumatic brain injury (TBI). However, patients with TBI-related lesions are often excluded from MRI analyses because cortical lesions may compromise the accuracy of reconstructed surfaces upon which volumetric measurements are based. We developed a FreeSurfer-based lesion correction method and tested its impact on cortical volume measures in 87 patients with chronic moderate-to-severe TBI. We reconstructed cortical surfaces from T1-weighted MRI scans, then manually labeled and removed vertices on the cortical surfaces where lesions caused inaccuracies. Next, we measured the surface area of lesion overlap with seven canonical brain networks and the percent volume of each network affected by lesions.•The lesion correction method revealed that cortical lesions in patients with TBI are preferentially located in the limbic and default mode networks (95.7% each), with the limbic network also having the largest average surface area (4.4+/−3.7%) and percent volume affected by lesions (12.7+/−9.7%).•The method has the potential to improve the accuracy of cortical volumetric measurements and permit inclusion of patients with lesioned brains in MRI analyses.•The method also provides new opportunities to elucidate network-based mechanisms of neurological deficits in patients with TBI.

Highlights

Cortical volumetric analysis with FreeSurfer[1, 2] is widely used to study the neuroanatomic basis of cognitive, behavioral, and motor deficits in patients with traumatic brain injury (TBI).[3,4,5,6]cortical lesions caused by TBI pose major challenges to FreeSurfer’s standard automated magnetic resonance imaging (MRI) processing pipeline
Development of a tool that accounts for lesions in cortical volumetric analysis is needed to prevent the systematic exclusion of patients with large cortical lesions and to ensure that TBI imaging studies are generalizable across the full spectrum of cortical pathology
We introduce a new FreeSurfer-based method for cortical volumetric analysis in patients with lesions caused by TBI

Summary

Introduction

Cortical volumetric analysis with FreeSurfer[1, 2] is widely used to study the neuroanatomic basis of cognitive, behavioral, and motor deficits in patients with traumatic brain injury (TBI).[3,4,5,6]cortical lesions caused by TBI pose major challenges to FreeSurfer’s standard automated magnetic resonance imaging (MRI) processing pipeline. Cortical volumetric analysis with FreeSurfer[1, 2] is widely used to study the neuroanatomic basis of cognitive, behavioral, and motor deficits in patients with traumatic brain injury (TBI).[3,4,5,6]. Lesions often compromise the accuracy of the cortical surfaces that are reconstructed and used by FreeSurfer to generate volumetric measurements.[4, 6, 7] As a result, TBI imaging studies have historically excluded patients with large focal lesions.[5, 8] Development of a tool that accounts for lesions in cortical volumetric analysis is needed to prevent the systematic exclusion of patients with large cortical lesions and to ensure that TBI imaging studies are generalizable across the full spectrum of cortical pathology Integration of such a tool into the FreeSurfer software platform would create new opportunities to study network-based mechanisms of disease[9, 10] using canonical atlases.[11]

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