Article Figures & Data
Figures
- Fig 1.
Orthogonal axial/coronal (A) and axial (B) projection of T1-weighted MR images with fiber tracts depicted in color in the healthy volunteer (violet and yellow, lip fibers; green and red, hand fibers; pale blue and dark blue, foot fibers) The hand and foot fibers of the corticospinal and the lip fibers of the corticobulbar tract can be clearly distinguished and visualized (A and B). The different fMRI activation areas used to choose the seed regions of interest are shown in color (A). The course of the fibers through the corona radiata follows the known somatotopic distribution (B). C, The results are shown from conventional DT tractography (in orange) as well as from fMRI-based fiber tracking with region-of-interest placement in the PMA of the lip of the right hemisphere (in green), projected on a coronal T1-weighted image of the healthy volunteer. fMRI activation (shown in yellow-orange) is visible in the PMA of the lip and supplementary motor area in both images. Clearly, the lip fibers are only visualized by using the fMRI-based fiber tracking approach and not with the conventional fiber tracking approach.
- Fig 2.
Axial T1-weighted MR image of a patient with a brain tumor with fibers of the corticospinal tract projected in color. Results from conventional fiber tracking based on anatomic landmarks (in orange) show dispersion and diminished visualization of the CST fibers in the hemisphere affected by the lesion (arrowheads), compared with the unaffected hemisphere. DT tractography based on seed region-of-interest selection in the PMA of the hand as established with fMRI shows, in blue, the CST fibers of the hand in the affected hemisphere, allowing a clear demarcation of the fibers of interest within the CST.
- Fig 3.
Orthogonal axial/sagittal projection of a T1-weighted MR image with overprojection of the hand PMA and the hand fibers of the CST. In this patient, the left PMA, as shown by fMRI (in orange-yellow), was displaced by tumor, as was the tracked CST (in green).
- Fig 4.
Axial T1-weighted MR image with fiber tracts projected in color (red and green for the right and left hemispheres, respectively). In this patient, hand fibers ran through an area of altered signal intensity, due to edema or tumor infiltration.
- Fig 5.
Axial T1-weighted MR images with foot fibers projected in color. Fibers pass through an area of altered signal intensity on T1-weighted images. Varying the FA thresholds for fiber tracking in this patient had a considerable influence on the fibers depicted (A–C, FA thresholds used are shown in each image).
Tables
Subject Pathologic Diagnosis Functional Neurologic Status Type of Motor Task No./Sex/Age Preoperative Postoperative Finger Tapping Foot Tapping Lip Pouting 1/F/27 N/A N/A N/A L, R L, R Y 2/F/42 Anaplastic oligoastrocytoma Severe left-sided hemiparesis Unchanged L, R Y 3/M/56 High-grade oligodendroglioma Minor left-sided hemiparesis Unchanged L, R B 4/F/55 Anaplastic oligoastrocytoma No deficit Minor left-sided hemiparesis L, R Y 5/F/48 WHO grade II astrocytoma Minor paresis, left hand Additional minor paresis, left leg L, R B 6/F/31 Low-grade astrocytoma No deficit Subtle disturbances of fine motor skills, right hand R 7/M/44 Low-grade oligodendroglioma No deficit No deficit L, R 8/F/42 No certain pathologic diagnosis* No deficit No deficit R B 9/F/35 Low-grade glioma No deficit Minor paresis, left hand B B 10/M/59 Arteriovenous malformation No deficit No deficit B Y Note:—F indicates female; M, male; N/A, not applicable (healthy volunteer); B, task performed on both sides simultaneously; R, task performed with right body side; L, task performed with left body side; Y, task performed; WHO, World Health Organization.
* Possibly resolving ischemic infarction.
- Table 2:
Overview of the most important findings by fMRI and DT tractography in each subject
No. PMA on fMRI Fiber Tracts on fMRI-Driven DT Tractography 1 Healthy volunteer: PMAs of hand, foot, and lip on both sides at known anatomic position Hand, foot, and lip fibers on both sides at known anatomic position 2 PMA of hand displaced laterally and caudally by tumor Hand fibers on tumor side displaced compared with healthy side, visualization of lip fibers only on healthy side 3 PMA of hand and foot displaced by tumor and in area of decreased signal intensity on T1WI Hand and foot fibers displaced on tumor side, run through area of altered signal intensity on T1WI 4 PMA at distance from lesion Hand fibers run very close to tumor border, lip fibers visualized only on healthy side 5 PMA of hand and foot in area of altered signal intensity on T1WI, near tumors Hand fibers normal course, foot fibers run through area of altered signal intensity on T1WI, close to tumor 6 PMA of hand displaced cranially and dorsally Hand fibers displaced by tumor 7 PMA not displaced and not related to tumor border Hand fibers not displaced 8 PMA not displaced and not related to tumor border Hand and foot fibers not displaced 9 PMA not displaced and not related to tumor border Hand and foot fibers not displaced 10 PMA not displaced and not related to AVM border Hand fibers not displaced, visualization of lip fibers on both sides Note:—T1WI indicates T1-weighted images; AVM, arteriovenous malformation.
