A comparison of diffusion MRI presurgical tractography techniques with intraoperative mapping-based validation

Abstract

AbstractObjectivesAccurate presurgical brain mapping enables preoperative risk assessment and intraoperative guidance. This work investigated whether constrained spherical deconvolution (CSD) methods were more accurate than diffusion tensor imaging (DTI)-based methods for presurgical white matter mapping using intraoperative direct electrical stimulation (DES) as the ground truth.Material and methodsFive different tractography methods were compared (3 DTI-based and 2 CSD-based) in 22 preoperative neurosurgical patients. The corticospinal tract (CST, N=20) and arcuate fasciculus (AF, N=7) bundles were reconstructed, then minimum distances between tractograms and DES coordinates were compared between tractography methods. Receiver-operating characteristic (ROC) curves were used for both bundles. For the CST, binary agreement, linear modeling, and posthoc testing were used to compare tractography methods while correcting for relative lesion and bundle volumes.ResultsDistance measures between 154 positive (functional response, pDES) and negative (no response, nDES) coordinates, and 134 tractograms resulted in 860 data points. Higher agreement was found between pDES coordinates and CSD-based compared to DTI-based tractograms. ROC curves showed overall higher sensitivity at shorter distance cutoffs for CSD (8.5 mm) compared to DTI (14.5 mm). CSD-based CST tractograms showed significantly higher agreement with pDES, which was confirmed by linear modeling and posthoc tests (PFWE < 0.05).ConclusionCSD-based CST tractograms were more accurate than DTI-based ones when validated using DES-based assessment of motor and sensory function. This demonstrates the potential benefits of structural mapping using CSD in clinical practice.Clinical relevance statementCSD-based tractograms of the CST are more sensitive than DTI-based tractograms when validated against sensory-motor DES mapping. This also demonstrated the feasibility of fully-automated CSD-based tractography for presurgical planning of the CST.Graphical abstractPresurgical white matter mapping using probabilistic CSD tractography is more accurate and sensitive than manual DTI FACT or automated probabilistic DTI tractography. This study included 22 patients with DES data, which was used as the ground truth. Distance in mm between tractograms and DES data resulted in 860 datapoints, 685 of which belonged to the CST and were used for linear modeling, DTI = diffusion tensor imaging, CSD = constrained spherical deconvolution, TCK = tractogram/tractography, FWE = family-wise error rate, AUC = area under the curve