Article Figures & Data
Figures
- Fig 1.
A, Virtual 3D reconstruction (cortex surfacing method) of the right hemisphere in the navigation workstation showing the integration of data from iCM and fMRI in the case of patient 8. The iCM-defined central sulcus (yellow line), the iCM-defined sensorimotor target of the hand (red diabolo), and the fMRI-activated area after motor tasks of the hand (at initial analysis threshold, green area; at more restrictive values, white cross), the fMRI-activated area after motor of the tongue (at initial analysis threshold, orange area; at more restrictive values, yellow area) projected in the portion of the precentral gyrus anatomically devoted to the face (pink area). The iCM-defined motor target of the hand (red cross) corresponds spatially with the fMRI precentral activation (green area).
B, Virtual 3D reconstruction (cortex surfacing method) of the right hemisphere in the navigation workstation showing the integration of data from iCM and fMRI in the case of patient 21. The iCM-defined central sulcus (green line), the iCM-defined sensorimotor target of the hand (red diabolo), the fMRI-activated area after motor tasks of the hand (at initial analysis threshold, violet area; at more restrictive values, white cross), and the fMRI-activated area after motor of the foot (at initial analysis threshold, azure area; at more restrictive values, white cross) projected in the portion of the parasagittal precentral convexity. The iCM-defined motor target of the hand (red cross) corresponds spatially with the fMRI precentral activation (violet area). The significant postcentral activations obtained after sensory activation paradigms of the hand (orange area) and foot (blue area) enable validation of the precentral motor activations of the same segments.
- Fig 2.
Axial functional MR imaging sequences showing the bilateral precentral cortical activation after motor tasks of the left hand in patients 14 (A) and 20 (B), amputated from the right upper limb (blue cross, enabling correlation between both images on B). This activation is obtained for analysis threshold corresponding to P values much greater than .0001. Minor differences are observed in surface and distribution of the activation between both sides.
- Fig 3.
Correlation, in the navigation system, between the iCM-defined targets (center of a 1-cm area between 2 poles of the grid but represented by a red cross) and the contours of the fMRI-defined activation areas (green and pink surfaces for hand and face, respectively, including focus of highest significance [centroid of the blob, black cross] designated as “fMRI target”) at the initial (or more restrictive) analysis threshold corresponding to P < .001 (or P < .0001). These pictures and the surface of cortical activation are only illustrative and do not represent actual data.
A, When targets are unambiguous (focal/reproducible/significant/with no artifact), we estimate that they correspond spatially only if the contours of the fMRI-activated area include the target of highest iCM wave.
B, When repeated iCM recordings provide ambiguous (diffused, not reproducible, altered by artifacts) results (red pointed square crosses), we designate as the iCM target the one defined by the recording presenting the highest amplitude (red cross). If this target is projected within the contours of the fMRI-activated area, we estimate that targets from both techniques corresponded spatially. When no iCM target is available, no comparison is possible.
C, When spatial concordance between both targets was obtained with lower thresholds than that corresponding to P < .001 (ie, when P < .01), we estimate that the concordance is not significant.
Tables
fMRI activation areas and intraoperative cortical mapping target in the precentral gyrus of 21 patients
Pain* Neurological Status Quality of iCM fMRI Comparison of iCM and fMRI Hypoesthesia Allodynia Motricity iCM Target Obtained† Limitations of iSEP Limitations of iBS fMRI Target Obtained† Analysis Threshold (P Values)‡ Extent of fMRI Activation, Both Sides§ Distance between Targets (mm)‖ Concordance between Targets, Both Techniques¶ 1/40/F Face TN + Normal Hand + Electrical artifacts Electrical artifacts Hand +++ <.0001 Similar extent 5 Good: fMRI helped iCM targeting Face 0 Electrical artifacts Electrical artifacts Face not studied 2/62/M UL ScS ++ Plegic Hand +++ Plegic Hand ++ <.0001 Healthy side > painful side 3 Excellent 3/65/F LL SS + Paretic Hand +++ Hand +++ <.0001 Similar extent 5 Excellent Foot ++ Foot ++ <.001 Not studied 8 Good: fMRIhelped iCM targeting 4/44/M UL ScS ++ Plegic Hand +++ Plegic Hand ++ <.0001 Healthy side > painful side 3 Excellent 5/33/F UL ScS + Normal Hand +++ Hand +++ <.0001 Similar extent 3 Excellent 6/66/F UL ScS + Paretic Hand +++ Hand +++ <.0001 Similar extent 4 Excellent 7/34/M UL PA + Plegic Hand + Wave attenuation Plegic Hand ++ <.0001 Healthy side > painful side 5 Good: fMRI helped iCM targeting 8/38/F Face TN + Normal Hand +++ Hand +++ <.0001 Similar extent 6 Excellent Face 0 No wave No response Face not studied 9/70/M UL SS + Paretic Hand +++ Hand +++ <.0001 Similar extent 3 Excellent 10/65/F UL PRP +++ Plegic Hand + Wave attenuation Plegic Hand +++ <.0001 Similar extent 3 Good: fMRI helped iCM targeting 11/50/F Face TN + Normal Hand +++ Hand +++ <.0001 Similar extent 5 Excellent Face ++ Diffused response Face not studied 5 12/73/M UL A +++ None Hand + Wave attenuation Amputation Hand + <.001 Healthy side > painful side 6 Good: fMRI helped iCM targeting 13/70/M Face TN + Normal Hand +++ Hand +++ <.0001 Similar extent 3 Excellent Face 0 Wave attenuation Not studied Face not studied 14/40/M UL A +++ None Hand + Wave attenuation Amputation Hand +++ <.0001 Similar extent 3 Good: fMRI helped iCM targeting 15/54/F LL ScS + Paretic Hand + Wave attenuation Hand ++ <.0001 Similar extent 3 Good: fMRI helped iCM targeting Foot 0 No wave Not studied Foot ++ <.0001 Not studied 5 Good: fMRI helped iCM targeting 16/56/F Face TN + Normal Hand +++ Hand + <.01 Not studied 4 Good: low fMRI significance Face ++ Face not studied 17/45/M Face TN +++ Normal Hand +++ Hand +++ <.0001 Similar extent 3 Excellent Face 0 No wave Face ++ <.0001 Not studied 5 Good: fMRI helped iCM targeting 18/66/F UL ScS + Normal Hand +++ Hand +++ <.0001 Similar extent 1 Excellent Face Face 0 No wave No response Face ++ <.001 Not studied 19/59/F UL ScS ++ Paretic Hand +++ Hand +++ <.0001 Similar extent 3 Excellent Face Face 0 No wave No resposne Face 0 <.001 20/43/M UL PA ++ Plegic Hand + Wave attenuation Plegic Hand +++ <.0001 Healthy side > painful side 4 Excellent 21/72/M UL ScS + Paretic Hand +++ Artifacts Hand +++ <.0001 Similar extent 5 Excellent LL Foot + Wave attenuation No response Foot ++ <.0001 Not studied Note.—iCM indicates intraoperative epidural cortical brain mapping; fMRI, functional magnetic resonance imaging; iSEP, intraoperative somatosensory-evoked potentials; iBS, intraoperative epidural motor cortex bipolar stimulodetection.
* UL indicates upper limb; LL, lower limb; TN, trigeminal neuropathy; ScS, subcortical stroke; SS, spinal syrinx; PA, plexus avulsion; PRP, postradic plexopathy; A, amputation.
† Quality scales for iCM and fMRI targeting are: 0, no significant target; +, fair and ambiguous target; ++, unambiguous target altered by artifacts/wave attenuation; +++, unambiguous and precise target.
‡ P values correspond to the analysis threshold of fMRI activation areas. Values less than .001 correspond to the initial analysis threshold; some targets remained significant for values less than .00001.
§ Not studied indicates that comparisons between both sides were not studied because of alterations resulting from residual motion artifacts.
‖ Distances reported between targets were measured intraoperatively by means of the neuronavigation microscope. They are purely indicative and do not reflect the resolution of fMRI and iCM.
¶ Excellent/good indicate important/partial overlap between fMRI target or unambiguous/ambiguous iCM target (note that ambiguous iCM targets impede correlations for both targets at more restrictive P values).
