Acta Neurochirurgica

, Volume 155, Issue 4, pp 675–683

Validation of functional motor and language MRI with direct cortical stimulation

Experimental research - Brain Tumors

DOI: 10.1007/s00701-013-1624-1

Cite this article as:
Meier, M.P., Ilmberger, J., Fesl, G. et al. Acta Neurochir (2013) 155: 675. doi:10.1007/s00701-013-1624-1

Abstract

Background

Functional magnetic resonance imaging (fMRI) is a widely available method and is therefore progressively utilized in neurosurgical practice. This study was carried out to determine fMRI sensitivity and specificity and to emphasize the threshold dependence of fMRI data.

Methods

A total of 17 consecutive patients, scheduled for surgery on intracerebral lesions near eloquent brain areas, underwent preoperative motor (N = 12) and language (N = 5) fMRI. Functional data were analyzed with SPM software and displayed on a neuronavigation system for intraoperative guidance. High-risk maps for motor and language deficits obtained from direct electric cortical stimulation (DECS) were used for validation of functional activated areas. In a first analysis step, sensitivity and specificity were calculated in terms of a side-by-side correlation. The next step, the threshold dependence of fMRI data sensitivity and specificity, was estimated according to four statistical thresholds (p1 < 0.05, p2 < 0.0005, p3 < 0.00001, p4 < 0.0000001).

Results

Both functional imaging and DECS revealed definite results for the investigated areas in all patients. Calculation of sensitivity and specificity resulted in 100 % and 68 % for the motor group and a sensitivity of 75 % and specificity of 68 % for the language group at the fixed threshold analysis. Threshold-dependent analysis of the obtained data revealed a sensitivity/specificity relationship from 100 %/0 % at threshold (p1), 100 %/5 % at (p2), 74 %/9 % at (p3), and 37 %/36 % at (p4) for the motor group. Evaluation of threshold-dependent sensitivity and specificity for the language group resulted in 78 %/51 % at threshold (p1), 67 %/75 % at (p2), 50 %/78 % at (p3), and 33 %/89 % at (p4).

Conclusions

The present findings on the threshold dependence of fMRI data demonstrate why individualized thresholds should be obtained in case of fMRI evaluation. Although the results are satisfying in most cases, fMRI is apparently not sufficient for critical intraoperative decision-making.

Keywords

Functional magnetic resonance imaging Electric/direct cortical stimulation Motor and language mapping Brain lesion 

Copyright information

© Springer-Verlag Wien 2013

Authors and Affiliations

  • M. P. Meier
    • 1
  • J. Ilmberger
    • 2
  • G. Fesl
    • 3
  • M. I. Ruge
    • 4
  1. 1.Department of Neurosurgery, Klinikum BogenhausenStädtisches Klinikum MünchenMunichGermany
  2. 2.Department of Physical Medicine and RehabilitationLudwig Maximilian University MunichMunichGermany
  3. 3.Department of NeuroradiologyLudwig Maximilian University MunichMunichGermany
  4. 4.Department of Stereotactic and Functional NeurosurgeryUniversity of CologneCologneGermany

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