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Several major association fiber tracts are known to be part of the language processing system. There is evidence that high angular diffusion-based MRI is able to separate these fascicles in a constant way. In this study, we wanted to proof this thesis using a novel whole brain “global tracking” approach and to test for possible lateralization. Global tracking was performed in six healthy right-handed volunteers for the arcuate fascicle (AF), the medial longitudinal fascicle (MdLF), the inferior fronto-occipital fascicle (IFOF), and the inferior longitudinal fascicle (ILF). These fiber tracts were characterized quantitatively using the number of streamlines (SL) and the mean fractional anisotropy (FA). We were able to characterize the AF, the MdLF, the IFOF, and the ILF consistently in six healthy volunteers using global tracking. A left-sided dominance (LI > 0.2) for the AF was found in all participants. The MdLF showed a left-sided dominance in four participants (one female, three male). Regarding the FA, no lateralization (LI > 0.2) could be shown in any of the fascicles. Using a novel global tracking algorithm we confirmed that the courses of the primary language processing associated fascicles can consistently be differentiated. Additionally we were able to show a streamline-based left-sided lateralization in the AF of all right-handed healthy subjects.

Purpose Global tracking (GT) is a recently published fibre tractography (FT) method that takes simultaneously all fibres into account during their reconstruction. The purpose of this study was to compare this new method with fibre assignment by continuous tracking (FACT) and probabilistic tractography (PT) for the detection of the corticospinal tract (CST) in patients with gliomas. Methods Tractography of the CST was performed in 17 patients with eight low grade and nine anaplastic astrocytomas located in the motor cortex or the corticospinal tract. Diffusions metrics as fractional anisotropy (FA), mean (MD), axial (AD) and radial diffusivity (RD) were obtained. The methods were additionally applied on a physical phantom to assess their accuracy. Results PT was successful in all (100 %), GT in 16 (94 %) and FACT in 15 patients (88 %). The case where GT and FACT, both, missed the CST showed the highest AD and RD, whereas the one where FACT algorithm, alone, was not successfully showed the lowest AD and RD of the group. FA was reduced on the pathologic side (FApath 0.35 ± 0.16 (mean ± SD) versus FAcontralateral 0.51 ± 0.15, pcorr

a 53-year-old woman presenting symptomatic epilepsy with simple and complex partial seizures since the age of 13 years was referred to our hospital for epilepsy surgery. Presurgical epileptic work-up had included electroencephalography monitoring, neuropsychological investigations, fluorodeoxyglucose positron emission tomography, and neuroradiologic evaluation. Magnetic resonance imaging (MRi) of the brain showed a lesion of the left medial temporal lobe (Fig. 1, 2). Based on the results of presurgical evaluation, two-thirds resection of the temporal lobe with amygdalohippocampectomy was suggested. epilepsy surgery was performed via a left frontotemporal approach with progressive removal of the lateral temporal cortex. During surgery, the hippocampus appeared very hard with dorsal calcifications. The arachnoid overlying the brainstem was abnormally thick and extremely adherent. However, the temporomesial mass could finally be resected in toto. Postoperative neurological examination revealed a slight hemiparesis and a hemianopsia. The computed tomography (CT) scan demonstrated a small dorsal thalamic infarction (not shown). The hemiparesis normalized during the following days.

Primary goal of magnetic resonance imaging in epilepsy patients is to detect epileptogenic lesions with small lesions best detectable on a 3D FLAIR SPACE sequence with 1 mm(3) voxels. Morphometric analysis of 3D T1-weighted data sets helps to find subtle lesions and may reveal the true extent of a lesion. In further presurgical work-up, language lateralization and spatial relationship of epileptogenic lesions to eloquent cortex and white matter tracts must be evaluated. With clear left lateralization language, fMRI is sufficient; in atypical lateralizations, Wada test and electrical stimulation mapping may be added. Primary motor cortex and corticospinal tract on one and visual cortex and optic radiation on the other side are displayed with fMRI and diffusion tensor tractography. For the corticospinal tract a "global" tracking algorithm, for the optic radiation including Meyer' loop, which may be damaged in anterior temporal lobe resections, a probabilistic algorithm is best suited.

a 61-year-old woman developed progressive exophthalmos of the left ocular bulb over a period of several weeks. she complained of conjunctival irritation, increased lacrimation, and associated gait disturbance. Ophthalmologic examination showed no visual field deficit and a visus of 0.8 versus 1.0 on her right eye. These findings remained stable at follow-up 4 weeks later. at clinical examination no neurological deficit was observed. Magnetic resonance imaging (MRI) revealed a left-sided orbital, intra-conal lesion. Lateral orbital decompression (according to Kronlein) was performed with resection of the lateral orbital wall and the orbital roof. Opening the periorbita, the capsulated tumour was situated in the intra-conal fat tissue. The tumour capsule was mostly of a white colour with some vascular injections and also adherent veins. after coagulation and opening of the capsule, the tumour was of a tough and adherent consistence, appearing white-greyish. intra-capsular tumour reduction without manipulation of the optic nerve could be achieved. The post-operative course was uneventful without visual impairment. Mild ptosis and diplopia resolved completely within several days. Imaging