Role of diffusion tensor magnetic resonance tractography in predicting the extent of resection in glioma surgery
Advance Access publication October
Role of diffusion tensor magnetic resonance tractography in predicting the extent of resection in glioma surgery
Antonella Castellano 0 1 2
Lorenzo Bello 0 1 2
Caterina Michelozzi 0 1 2
Marcello Gallucci 0 1 2
Enrica Fava 0 1 2
Antonella Iadanza 0 1 2
Marco Riva 0 1 2
Giuseppe Casaceli 0 1 2
Andrea Falini 0 1 2
0 (C.M.); and Department of Psychology, Universita` di Milano-Bicocca (M.G.) , Milan , Italy
1 A.F.); Neurosurgery, Department of Neurological Sciences, Universit a` degli Studi di Milano , and Istituto
2 Neuroradiology Unit and CERMAC, Scientific Institute and Universita` Vita-Salute San Raffaele (A.C., A.I.
Clinico Humanitas (L.B., E.F., M.R., G.C.); Institute of Radiological Sciences, Universita` degli Studi di Milano considered to be a promising tool for estimating preoperatively the degree of radicality to be reached by surgical resection. This information will aid clinicians in identifying patients who will mostly benefit from surgery.
Diffusion tensor imaging; DTI tractography; extent of resection; glioma surgery; presurgical planning
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Diffusion tensor imaging (DTI) tractography enables the
in vivo visualization of the course of white matter tracts
inside or around a tumor, and it provides the surgeon
with important information in resection planning. This
study is aimed at assessing the ability of preoperative
DTI tractography in predicting the extent of the
resection achievable in surgical removal of gliomas. Patients
with low-grade gliomas (LGGs; 46) and high-grade
gliomas (HGGs; 27) were studied using a 3T scanner
according to a protocol including a morphological
study (T2, fluid-attenuated inversion-recovery, T1
sequences) and DTI acquisitions (b 5 1000 s/mm2, 32
gradient directions). Preoperative tractography was
performed off-line on the basis of a streamline algorithm, by
reconstructing the inferior fronto-occipital (IFO), the
superior longitudinal fascicle (SLF), and the
corticospinal tract (CST). For each patient, the relationship
between each bundle reconstructed and the lesion was
analyzed. Initial and residual tumor volumes were
measured on preoperative and postoperative 3D
fluidattenuated inversion-recovery images for LGGs and
postcontrast T1-weighted scans for HGGs. The presence
of intact fascicles was predictive of a better surgical
outcome, because these cases showed a higher
probability of total resection than did subtotal and partial
resection. The presence of infiltrated or displaced CST
or infiltrated IFO was predictive of a lower probability
of total resection, especially for tumors with
preoperative volume <100 cm3. DTI tractography can thus be
Cinvolving both cortical and subcortical
strucerebral gliomas are highly invasive neoplasms
tures. These tumors are frequently located in or
close to eloquent areas, and they are characterized by a
diffuse and infiltrative pattern of growth, because
invasive glioma cells are frequently found to migrate along
myelinated fiber tracts of white matter (WM).1 WM is
crucial for brain function, and its pathological
involvement correlates with neurological or neuropsychological
findings;2,3 however, low-grade gliomas (LGGs)
typically grow slowly and often spare neural function as
they infiltrate eloquent brain areas, and patients
usually have normal neurological examination findings.4
Diffusion tensor imaging (DTI) tractography is
widely applied in patients with glioma,5,6 because this
advanced magnetic resonance (MR) technique is the
only noninvasive method allowing the in vivo
identification of the trajectories of WM tracts adjacent to or
inside the tumor.6 DTI tractography can show the
various effects exerted by the tumor on WM tracts,
providing information about the normal course, the
displacement, or the infiltration of the fascicles.5 – 7
Intraoperative subcortical brain mapping studies8,9
recently showed that DTI tractography data are reliable
and accurate in describing the trajectories of the tracts
and their modifications induced by the lesions, because
tracking results correlated with those obtained by direct
electrical stimulation. At present, DTI tractography is
specifically used as a preoperative examination to
improve neurosurgical planning,9 – 13 and it is usually
uploaded to the neuronavigation system together with
morphological and functional images.14 This means
that patients undergo DTI tractography when a surgical
procedure has already been planned.
The aim of this study was to investigate whether DTI
tractography could be useful, even a step earlier, as a
tool to select which patients will benefit the most from
surgery, obtaining a total resection, and thus, having
longer overall survival.15 – 17 The major WM tracts
responsible for eloquent functions were preoperatively
reconstructed in patients with supratentorial brain
gliomas involving speech or motor areas or pathways.
The corticospinal tract (CST) and 2 of the main fiber
bundles involved in the phonologic and semantic lo (...truncated)