MRI-Tractography for detecting the position of corticospinal tract in preoperative meningioma
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1) T1-weighted MRI post-Gadolinium demonstrates an extra-axial mass consistent with a meningioma.
2) RGB color map.
3) RGB color map, co-registered with a weighted RM T1 3D Gradient Echo demonstrates mass effect and distortion of the right corticospinal tract (red), which appears displaced but not interrupted.
4) Video 3D - The spatial relationship between the right corticospinal tract and the meningioma (RGB Color map, + FLAIR + FTT).
The right corticospinal tract was reconstructed using the red color; the left corticospinal tract was reconstructed using the green color.
MRI-Tractography allows the identification in vivo the brain white matter tracts adjacent to the injury. One of its applications is preoperative planning for brain tumor resection (e.g. meningioma). This is important in neurosurgery planning of a safer access route with less residual functional iatrogenic deficits.
A 1.5 T Philips Achieva was used. DTI data were acquired using a single-shot echo-planar imaging (EPI) sequence with SENSE parallel imaging * (EPI factor = 59). Spin Echo technique (TR = 11090 ms; TE = 107 ms; Flip Angle = 90°; nex = 2). The imaging matrix was 112 x 112, with a field of view of 224 x 224 mm. The image orientation was axial, with a 2.0 mm slice thickness (slice gap = 0 mm), which was aligned parallel to the anterior-posterior commissure line. A total of 60 slices covered the entire cerebral hemispheres and the brainstem. The diffusion weighting was encoded along 32 independent orientations, with a maximum b-value = 800 s/mm2. The scanning time of one dataset was about 12 min. A co-registered T1-weighted 3D Gradient Echo was also recorded for anatomical guidance.
* SENSE parallel imaging was used to reduce the length of the EPI-train, thereby reducing susceptibility related distortions.
Reconstruction of tracts
The 3D tract reconstruction was performed using the FACT (Fiber Assignment by Continuous Tracking) method. Maximum Angle Change: 25°, Minimum FA: 0.2, Minimum Fiber Length: 0.68 cm.
Three ROIs are used for each tract: the 1st placed on the precentral gyrus (axial slice); the 2nd on the genu and posterior limb of the internal capsule (axial slice); the 3rd on Piramide bulbar (axial slice).
A. Politi, MD and G. M. Latagliata, MD.
Disclosure: I, Francesco Sciacca, have no actual or potential ethical or financial conflict of interest in relation to this device. This case is not intended to be a personal endorsement or recommendation of this product.
- Francesco SCIACCA: "FIBER-TRACKING TECHNIQUE. Neuroimaging anatomico dei sistemi associativi, commissurali e dei collegamenti proiettivi" - PhD Research Project. Messina University, PhD in Clinical and translational research in neuroscience and oncology (2014). Biblioteca nazionale centrale di Roma, DPR 382/80 e DM 224/99 – (http://bncrm.beniculturali.it).