Recently, a novel leukoencephalopathy syndrome was described in eight patients with a distinct pattern of MRI abnormalities. Here we describe the clinical, laboratory, and MRI findings in five new, unrelated patients. The clinical picture was homogeneous with onset in childhood, a slowly progressive course, variable mental deficits, signs of pyramidal and cerebellar dysfunction and sometimes dorsal column dysfunction. In two patients, a minor head trauma was followed by neurological deterioration and fever. No underlying metabolic defect was found. In two patients serum lactate was elevated, but no evidence of a mitochondrial defect was found. MRI showed variably extensive, diffuse, or spotty cerebral white matter abnormalities and a selective involvement of particular brainstem tracts. The tracts involved included the pyramidal tracts, sensory tracts, superior and inferior cerebellar peduncles, and intraparenchymal trajectories of the trigeminal nerve. In four patients spinal MRI was performed and revealed involvement of tracts over the entire length depicted. Single voxel proton MRS in three patients revealed increased lactate within the abnormal white matter. The uniform and highly characteristic MRI findings, in combination with the similarities in clinical and MRS findings, provide evidence for a distinct nosological entity.

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To evaluate Gd-DTPA contrast enhancement of brain tumors over time and to describe the dispersion of contrast into the zone of peritumoral edema. We performed MR imaging with a dose of 0.4 mmol Gd-DTPA/kg on eleven patients diagnosed with 5 different supratentorial tumors. MR imaging was done at five intervals between 5 min and 6 h. The change in zone of enhancement was measured for each time point, and a linear measurement was made of the furthest dispersion of contrast from the original volume of enhancement. An increase in the zone of enhancement over time was seen for all tumors; the average increase in volume of contrast was 14.76 +/- 3.35 cm(3) (mean +/- standard deviation). The largest changes in the zone of contrast enhancement, 18.6 +/- 4.63 cm(3), were seen in glioblastoma multiforme. The expansion of contrast enhancement assumed the morphology of the surrounding edema. The dispersion of Gd-DTPA over time into the zone of peritumoral edema is a potential source of error in clinical settings when there is a delay between Gd-DTPA injection and scanning.

Intraoperative direct third ventriculostomy and aqueductal stenting under direct visual control were found to be reliable methods of hydrocephalus management in patients with deep-seated midline brain tumors.

Aim: to explore the opportunities of application of diffusionkurtosis imaging (DKI) for assessment and estimation of diffusion scalar metrics in different locations of peritumoral edema for extra- and intracerebral tumors and in contralateral normal tissue.Materials and methods. 38 patients with supratentorial brain tumors were investigated: 24 (63%) patients with primarily revealed glioblastomas (GB) and 14 (37%) patients with solitary cancer brain metastasis (MTS). MRI was performed on 3.0 T MR-scanner (Signa HDxt, General Electric, USA) with the standard protocols for brain tumor and additional protocol for DKI. The standard protocol for brain tumor included: T1-, T2-weighted images, T2-FLAIR, DWI,  T1 with contrast enhancement. Diffusion kurtosis MRI based on SE  EPI with TR = 10000 ms, TE = 102 ms, FOV = 240 mm, isotropic voxel size 3 × 3 × 3 mm3, 60 noncoplanar diffusion directions. We  used three b-values: 0, 1000 and 2500 s/mm2. Аcquisition time was 22 min. Total acquisition time was near 40 min. This study was approved by Ethical committee of Burdenko National Scientific  and Practical Center for Neurosurgery. Parametric maps were  constructed for the following diffusion coefficients: mean (MK),  transverse / radial (RK), longitudinal / axial (AK) kurtozis; medium  (MD), transverse / radial (RD) and longitudinal / axial (AD) diffusion; fractional anisotropy (FA) and a bi-exponential diffusion model  coefficients: axonal water fractions (AWF), axial (AxEAD) and radial  (RadEAD) extra-axonal water diffusion and the water molecules  trajectory tortuosity index (TORT). Normative quantitative indicators  were obtained for the six regions of the peritumoral zone as they  moved away from the tumor (region 2) to the edema periphery  (regions 4–5), as well as in the normal brain on the contralateral  hemisphere (C/L) (zone 7). A comparative analysis of these  indicators was conducted for cases with GB and MTS. DKI scalar metrics were estimated using Explore DTI (http://www.exploredti.com/).Results. Anatomic MRI (T1 without/with contrast enhancement) for  all cases with GB and MTS visualized a contrast enhancement tumor.  The peritumoral edema, spreading mainly over the brain white  matter, was well visualized on T2-FLAIR. Diffusion kurtosis  coefficients decreased in the near peritumoral edema (regions 2–3)  and a gradually increased to the edema periphery (regions 5–6). In Region 2, MK in both GB and MTS groups were MKGB(2) = 0.637 ±  0.140 and MKMTS(2) = 0.550 ± 0.046; RK in this region were  RKGB(2) = 0.690 ± 0.154 and RKMTS (2) = 0.584 ± 0.051.  Differences both MK and RK coefficients in patients with GB and MTS of region 2 were significant (p < 0.001). There were no differences in AK values for GB and MTS in region 2 (p > 0.05), but in regions 3  and 4 differences were observed (p < 0.01). The minimum value of  AK in the central edema (regions 3–4) was AKMTS(3–4) = 0.433 ± 0.063 in patients with MTS. The values of MK and RK on the  contralateral side in patients with MTS were significantly higher than  in the GB group (p < 0.02); MKC/LMTC = 0.954 ± 0.140, RKC/LMTC  = 1.257 ± 0.308 and MKC/LGB = 0.829 ± 0.146, RKc/LGB = 0.989  ± 0.282. There was no significant difference for contralateral AK between the groups.Conclusions. We found that DKI scalar metrics are the sensitive  tumor biomarkers. It allows us to perform a robust differentiation  between the infiltrating GB tumor and purely vasogenic edema of  МТS. The obtained results will allow further differential diagnosis of  extra- and intracerebral tumors and can be used to plan surgical /  radiosurgical treatment for brain tumors.