Diffusion tractography for awake craniotomy: accuracy and factors affecting specificity

Abstract

Introduction Despite evidence of correspondence with intraoperative stimulation, there remains limited data on MRI diffusion tractography (DT)’s sensitivity to predict morbidity after neurosurgical oncology treatment. Our aims were: (1) evaluate DT against subcortical stimulation mapping and performance changes during and after awake neurosurgery; (2) evaluate utility of early post-operative DT to predict recovery from post-surgical deficits. Methods We retrospectively reviewed our first 100 awake neurosurgery procedures using DT- neuronavigation. Intra-operative stimulation and performance outcomes were assessed to classify DT predictions for sensitivity and specificity calculations. Post-operative DT data, available in 51 patients, were inspected for tract damage. Results 91 adult brain tumor patients (mean 49.2 years, 43 women) underwent 100 awake surgeries with subcortical stimulation between 2014 and 2019. Sensitivity and specificity of pre-operative DT predictions were 92.2% and 69.2%, varying among tracts. Post-operative deficits occurred after 41 procedures (39%), but were prolonged (> 3 months) in only 4 patients (4%). Post-operative DT in general confirmed surgical preservation of tracts. Post-operative DT anticipated complete recovery in a patient with supplementary motor area syndrome, and indicated infarct-related damage to corticospinal fibers associated with delayed, partial recovery in a second patient. Conclusions Pre-operative DT provided very accurate predictions of the spatial location of tracts in relation to a tumor. As expected, however, the presence of a tract did not inform its functional status, resulting in variable DT specificity among individual tracts. While prolonged deficits were rare, DT in the immediate post-operative period offered additional potential to monitor neurological deficits and anticipate recovery potential.

Supratotal Resection of Gliomas With Awake Brain Mapping: Maximal Tumor Resection Preserving Motor, Language, and Neurocognitive Functions

“…MRI diffusion tractography (DT) is used to estimate subcortical fiber tracts before awake surgery. Voets et al evaluated DT sensitivity, specificity, and accuracy for five subcortical fiber tracts, including the corticospinal tract (CST), arcuate fasciculus (AF), inferior fronto-occipital fasciculus (IFOF), optic radiation (OR), and inferior longitudinal fasciculus (ILF) ( 33 ). The sensitivity and specificity of preoperative DT predictions were very high, at 92.2 and 69.2%, respectively, and it varied across tracts.…”

The Utilization of Diffusion Tensor Imaging as an Image-Guided Tool in Brain Tumor Resection Surgery: A Systematic Review

“…The articles were published from the year 2005 to 2021. The studies included both prospective studies (n = 9) [7,8,[19][20][21][22][23][24][25] and retrospective (n = 8) [1,[26][27][28][29][30][31][32]. Data collection was performed by extracting information on demographic data, composed of the author, year of publication, type of study, origin country, number of patients and participants, patients' mean age, tumor type and its histology, tumor location, and the details of the control group, as shown in Table 2.…”

“…This information is summarized in Table 2. The white matter tracts of interest in the studies were primarily those in close proximity to the tumor and those associated with brain function, such as the corticospinal tract related to motor function [19,20,27,[30][31][32], optic radiation responsible for eyesight [1,7,8,21,23,29,31], and inferior longitudinal fasciculus and arcuate fascicles that link to language [7,8,20,22,23,28,29,31]. These tracts were relevant for postoperative deficit assessment.…”

“…All of the studies discussed the utilization of the DTI in brain tumor resection. One of them was primarily concerned with the ability to reconstruct the fiber tract in the presence of a brain tumor [1,7,8,[19][20][21][22][23][24][25][26][27][28][29][30][31][32]. In addition, the use of DTI could predetermine the preplanning surgical approach [8].…”

“…In addition, the use of DTI could predetermine the preplanning surgical approach [8]. Evaluation of DTI was performed in comparison with control patients, non-DTI, and DTI patients' groups [1,[21][22][23]25,28]; intraoperatively evaluation [1,7,8,[19][20][21][22][23][24][25][26][27][28][29][30][31]; and quantified the sensitivity and specificity of the DTI technique in its tract identification, tumor resection rate, and mobility prediction [20,21,23,24,27,31]. We emphasized all these benefits of DTI for our primary investigation on whether re-evaluation and modifications of the preplanning surgery were made [7,8,26,27,29,30,32].…”