Abstract
BACKGROUND AND OBJECTIVES: Tractography of the corticospinal tract (CST) is routinely used for neurosurgical planning and navigation. It allows the noninvasive, patient-specific visualization of fiber tracts which can be used for surgical planning and risk stratification. This systematic review and meta-analysis sought to synthesize the accuracy of CST tractography by comparing diffusion tensor imaging (DTI)-based and fiber orientation distribution (FOD)-based tractography approaches to direct (sub)cortical electrical stimulation of motor fibers. METHODS: We systematically searched 4 databases (MEDLINE Ovid, Embase Ovid, Web of Science, CENTRAL) on 01.10.2024. Studies were included if they were (1) cross-sectional (2) original research studies that (3) had participants with motor-eloquent pathologies undergoing surgery, (4) performed intraoperative mapping of the CST, (5) compared stimulation sites with tractography, and (6) reported measures of test accuracy, e.g., sensitivity and specificity. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Data were analyzed using a fixed-effect logistic regression model to derive pooled effect estimates of sensitivity and specificity of DTI-based and FOD-based tractography. RESULTS: We included 16 studies of which 12 used DTI-based, 2 used FOD-based, and 2 used both DTI-based and FOD-based tractography. For DTI-based tractography, sensitivity ranged from 25% to 100% and specificity from 55.6% to 100%. For FOD-based tractography, sensitivity ranged from 36% to 79% and specificity from 77% to 98%. Clinically, 10 studies reported functional outcomes, although the time of postoperative testing varied: 1 study reported a decrease, 6 a preservation, and 3 an improvement in motor function at follow-up. CONCLUSION: Overall, incomplete reporting prevented a quantitative comparison of DTI-based and FOD-based tractography. Although 2 studies indicate that FOD-based tractography may be superior to DTI-based tractography for sensitivity in a clinical setting, evidence to this end is, as of yet, insufficient. Future cross-sectional studies evaluating multiple tractography approaches within one setting are recommended.