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August 2022, Volume 72, Issue 8

Evidence Based Neuro-Oncology

Role of diffusion tensor imaging for brain tumour resection

Mujtaba Khalil  ( Section of Neurosurgery, Department of Surgery, Aga Khan University Hospital, Karachi, Pakistan. )
Kaynat Siddiqui  ( Section of Neurosurgery, Department of Surgery, Aga Khan University Hospital, Karachi, Pakistan. )
Ahmer Baig  ( Section of Neurosurgery, Department of Surgery, Aga Khan University Hospital, Karachi, Pakistan. )
Muhammad Shahzad Shamim  ( Section of Neurosurgery, Department of Surgery, Aga Khan University Hospital, Karachi. )

Abstract

Diffusion tensor imaging (DTI) is an advanced imaging technique that helps to establish the topographic-anatomical relationship of tumours with the surrounding white matter tracts. Intra-operatively when used with neuro-navigation, it helps in minimizing injury to functional brain parenchyma, decreasing the risk of post-operative neurological deficits. In this review, we have assessed the efficacy of DTI for brain tumour resection.

 

Keywords: Diffusion tensor imaging, Brain tumour.

 

DOI: https://doi.org/10.47391/JPMA.22-88

 

Introduction

 

Surgical resection remains the preferred treatment modality for intracranial tumours. Goals of surgery include preserving eloquent areas of the brain, minimizing postoperative neurological deficits, and improving progression-free survival through maximum resection. Along with surgical expertise, a better knowledge of topographic-anatomical relationship of tumour with adjacent tissue helps to achieve these goals. Recently, new advancements like functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have gained increased popularity in surgical neuro-oncology.1

As an advanced non-invasive modality, DTI helps in depicting the location and structural connectivity of the white matter tracts within the cortex in vivo.2 This works on the phenomenon of highly anisotropic water diffusion ability in these areas of the cortex that helps create a three-dimensional image of the tracts, which can be synced with intra-operative neuro-navigation systems2 (Figure-1-3). There is now sufficient literature supporting the addition of DTI for maximum safe resection of intra-axial tumours, with minimal functional deterioration.3-5 In this article we have reviewed the relevant literature on the use of DTI for brain tumour resection.

 

 

 

 

 

Review of Evidence

 

Wu et al., compared post-operative neurological outcomes of 118 patients who underwent brain tumour resection using DTI, with 120 control patients. Postoperative motor deterioration was significantly higher in the control group (32.8% vs 15.3%, P<0.001). Karnofsky Performance Scale (KPS) score at 6 months follow up was significantly higher in the DTI group (86 ± 20 versus 74 ± 28, P < 0.001), and the median survival time of the high-grade glioma patients in DTI group was 21.2 months as compared to 14.0 months of the control group (P = 0.048). The risk of mortality was also 43% lesser in the DTI group.6 Zhu et al., in a prospective cohort study of 50 cases observed DTI's sensitivity (92.6%) and specificity (93.2%) along with direct subcortical stimulation of pyramidal tract mapping in patients with gliomas adjacent to these descending motor tracts. Gross total resection was achieved by 40(69%) patients, 17 (29.3%) had worsening post-operative deficits, 1-month post-operative deficit was noticed in 1 case, while mean post-operative KPS was significantly better (P <0.001) in 50 cases as compared with their mean pre-operative scores.7 Yan et al., studied 31 patients with (mean age 56 years), with GBM who underwent standard surgery aided by MRI, DTI, and FLAIR.5 They reported that 24 (77%) patients had complete resection as seen in the postcontrast T1 weighted images; moreover, longer overall survival and progression-free survival were observed in DTI aided surgery.5

Vassal et al., reported 10 patients with gliomas located near the pyramidal tract who underwent surgery with preoperative mapping with DTI and subcortical stimulation. They reported that tumour volume reduced from 32 cm3 to 3.9cm3 with approximately 90% extent of resection. Four patients underwent gross total resection and only one patient had a persistent slight motor deficit at one month after surgery.8 Dubey et al., published a retrospective study of 34 patients with intra axial brain tumours, particularly gliomas and metastasis, and the role of DTI and MRI in preoperative surgical planning.9 DTI revealed the involvement or displacement of tracts by the tumour in every case. They observed that at a mean age of 48.3 years, 16 (47%) patients had gross total resection with 0% mortality in the studied group.9 However, 4 (11.7%) patients had worsened motor function, while, 5 (14.7%) patients showed improved motor power in the postoperative period.9 Moreover, in their study, 16 (47%) patients had cognitive defects, and 3 (8.82%) patients had language deterioration.9 Wende et al., in their extensive systemic review highlighted significant correlation between improved neurosurgical outcomes and DTI aided surgery.10 Furthermore, they also found the pertinent role of tractography in preserving cranial nerve functions in various skull base surgeries.10 Ung et al., in a systemic analysis discussed 36 cases of vestibular schwannoma excision with the help of preoperative or intraoperative planning with DTI to identify the facial nerve.11 They observed that localization of nerve was accurate in 32 (89%) patients, therefore, 84% had low-grade facial nerve deficit as compared to 16% with a high-grade deficit.11

Cao et al., in a retrospective case series of nine patients with brainstem lesions reported that DTI and fibre tractography could be used to localize the corticospinal tract and medial leminisci in a three-dimensional fashion.12 This helped them achieve complete resection of tumour in four patients, two with brainstem cavernomas and, two others with pilocytic astrocytoma. Although eight patients did functionally better in their post-operative period, only one patient with medulla oblongata astrocytoma deteriorated.12 Xiao et al., similarly reported 54 patients operated for brainstem gliomas with the help of DTI and tractography mapping, over two years.13 They reported that with a mean maximum tumour diameter of 24.6mm, 18(33.3%) cases had a change in surgical technique after the study of images obtained from DTI.13 They report that the corticospinal tract was deformed in 29 cases, and interrupted in 27 cases.13 Castellano A et al. in their landmark paper studied 73 consecutive cases of gliomas that underwent surgical resection with fMRI and DTI mapping of language and motor pathways. They predicted that tumour volume of <100cm3 and intact fasciculus was strongly related to the extent of tumour resection.14 Moreover, mean tumour volume reduced to 4 cm3 from 36.2 cm3 and 62 (85%) patients experienced transient motor deficits.14 Similarly, in a prospective study of 60 patients undergoing navigated transcranial magnetic stimulation (nTMS) and nTMS plus DTI as an adjunct to awake surgery for resection of gliomas found near the language eloquent areas, it was observed that only5 (8.3%) patients suffered from permanent language deficits whereas,15 (28.3%) had a residual tumour.

 

Conclusion

 

This extensive literature review supports the role of DTI along with other mapping techniques in resecting low and high-grade intracranial tumours with the improvement in extent of resection, post-operative functional preservation and survival.

 

References

 

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2.      Beaulieu C. The basis of anisotropic water diffusion in the nervous system-a technical review. NMR in Biomedicine: An International Journal Devoted to the Development and Application of Magnetic Resonance In Vivo. 2002;15:435-55.

3.      Vanderweyen DC, Theaud G, Sidhu J, Rheault F, Sarubbo S, Descoteaux M, Fortin D. The role of diffusion tractography in refining glial tumor resection. Brain Structure and Function. 2020;225:1413-36.

4.      Panigrahi M, Chandrasekhar YB, Vooturi S, Ram GA, Rammohan VS. Surgical resection of insular gliomas and roles of functional magnetic resonance imaging and diffusion tensor imaging tractography-single surgeon experience. World neurosurg. 2017;98:587-93.

5.      Yan JL, Van Der Hoorn A, Larkin TJ, Boonzaier NR, Matys T, Price SJ. Extent of resection of peritumoral diffusion tensor imaging-detected abnormality as a predictor of survival in adult glioblastoma patients. J Neurosurg. 2017;126:234-41.

6.      Wu JS, Zhou LF, Tang WJ, Mao Y, Hu J, Song YY, Hong XN, Du GH. Clinical evaluation and follow-up outcome of diffusion tensor imaging-based functional neuronavigation: a prospective, controlled study in patients with gliomas involving pyramidal tracts. Neurosurgery. 2007;61:935-49.

7.      Zhu FP, Wu JS, Song YY, Yao CJ, Zhuang DX, Xu G, Tang WJ, Qin ZY, Mao Y, Zhou LF. Clinical application of motor pathway mapping using diffusion tensor imaging tractography and intraoperative direct subcortical stimulation in cerebral glioma surgery: a prospective cohort study. Neurosurgery. 2012;71:1170-84.

8.      Vassal F, Schneider F, Nuti C. Intraoperative use of diffusion tensor imaging-based tractography for resection of gliomas located near the pyramidal tract: comparison with subcortical stimulation mapping and contribution to surgical outcomes. Br J Neurosurg.. 2013;27:668-75.

9.      Dubey A, Kataria R, Sinha VD. Role of diffusion tensor imaging in brain tumor surgery. Asian J. Neurosurg.. 2018;13:302.

10.    Wende T, Hoffmann KT, Meixensberger J. Tractography in neurosurgery: a systematic review of current applications. J Neurol Surg. Part A: Central European Neurosurgery. 2020;81:442-55.

11.    Ung N, Mathur M, Chung LK, Cremer N, Pelargos P, Frew A, Thill K, Mathur I, Voth B, Lim M, Yang I. A systematic analysis of the reliability of diffusion tensor imaging tractography for facial nerve imaging in patients with vestibular schwannoma. J Neurol Surg. Part B: Skull Base. 2016;77:314-8.

12.    Cao Z, Lv J, Wei X, Quan W. Appliance of preoperative diffusion tensor imaging and fiber tractography in patients with brainstem lesions. Neurol India. 2010;58:886.

13.    Xiao X, Kong L, Pan C, Zhang P, Chen X, Sun T, Wang M, Qiao H, Wu Z, Zhang J, Zhang L. The role of diffusion tensor imaging and tractography in the surgical management of brainstem gliomas. Neurosurg Focus. 202;50:E10.

 14.   Castellano A, Bello L, Michelozzi C, Gallucci M, Fava E, Iadanza A, Riva M, Casaceli G, Falini A. Role of diffusion tensor magnetic resonance tractography in predicting the extent of resection in glioma surgery. Neuro-oncol. 2011;14:192-202.

15.    Sollmann N, Kelm A, Ille S, Schröder A, Zimmer C, Ringel F, Meyer B, Krieg SM. Setup presentation and clinical outcome analysis of treating highly language-eloquent gliomas via preoperative navigated transcranial magnetic stimulation and tractography. Neurosurg Focus. 2018;44:E2.

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