[Periventricular changes following hydrocephalus: quantitative MR-based assessment of tissue characteristics]. / Periventrikulyarnye izmeneniya pri gidrotsefalii: kolichestvennaya otsenka tkanevykh kharakteristik metodom magnitno-rezonansnoi tomografii.

OBJECTIVE: To study tissue characteristics of periventricular white matter in patients with open hydrocephalus using DWI MRI and their correlations with CSF flow parameters. MATERIAL AND METHODS: MRI was performed in 55 patients (35 women and 20 men) with open normal pressure hydrocephalus, as well as 16 patients with malignant occlusive hydrocephalus and interstitial edema (control group). We determined the correlations between severity of hydrocephalus, periventricular lesions and CSF flow parameters considering MR data. Dimensions of ventricular system were assessed using the Evans' index, periventricular changes - using visual four-level scale with calculation of apparent diffusion coefficient (ADC) and fractional anisotropy coefficient (FA). RESULTS: Among patients with open hydrocephalus, ACD range for periventricular white matter was 1.57±0.15·10-3 mm2/s in subgroup of patients without periventricular changes (n=29) and 1.62±0.11×10-3 mm2/s in patients with periventricular changes (n=26). In the control group, mean ADC was 1.76±0.18·10-3 mm2/s (p<0.05). In patients with open hydrocephalus, FA coefficient in the areas of periventricular changes was 0.70-0.80, in case of occlusive hydrocephalus - 0.68-0.82. There was a significant relationship between the Evans' index and CSF pulsation velocity amplitude, Evans' index and stroke volume, Evans' index and cerebral aqueduct cross-sectional area in patients with open hydrocephalus. Periventricular changes were pronounced in patients with open hydrocephalus and Evans' index > 0.4 (p<0.05). CONCLUSION: According to MR data, periventricular changes in patients with open hydrocephalus differ from true periventricular interstitial edema following occlusive hydrocephalus. Severity of periventricular changes in patients with open hydrocephalus depends on patient age and width of the ventricles, but does not correlate with CSF flow parameters. In our opinion, periventricular changes are associated with dysfunction of glymphatic system. Further research is required to study the functioning of glymphatic system and related processes.

3D pCASL-perfusion in preoperative assessment of brain gliomas in large cohort of patients.

The aim of the study was to evaluate the role of pseudocontinuous arterial spin labeling perfusion (pCASL-perfusion) in preoperative assessment of cerebral glioma grades. The study group consisted of 253 patients, aged 7-78 years with supratentorial gliomas (65 low-grade gliomas (LGG), 188 high-grade gliomas (HGG)). We used 3D pCASL-perfusion for each patient in order to calculate the tumor blood flow (TBF). We obtained maximal tumor blood flow (maxTBF) in small regions of interest (30 ± 10 mm2) and then normalized absolute maximum tumor blood flow (nTBF) to that of the contralateral normal-appearing white matter of the centrum semiovale. MaxTBF and nTBF values significantly differed between HGG and LGG groups (p < 0.001), as well as between patient groups separated by the grades (grade II vs. grade III) (p < 0.001). Moreover, we performed ROC-analysis which demonstrated high sensitivity and specificity in differentiating between HGG and LGG. We found significant differences for maxTBF and nTBF between grade III and IV gliomas, however, ROC-analysis showed low sensitivity and specificity. We did not observe a significant difference in TBF for astrocytomas and oligodendrogliomas. Our study demonstrates that 3D pCASL-perfusion as an effective diagnostic tool for preoperative differentiation of glioma grades.

[Endoscopic endonasal reconstruction of skull base defects in the lateral recess of the sphenoid sinus: evaluation of computed tomograms for planning operations]. / Endoskopicheskaya endonazal'naya plastika defektov osnovaniya cherepa v oblasti lateral'nogo karmana klinovidnoi pazukhi: otsenka komp'yuternykh tomogramm dlya planirovaniya operatsii.

OBJECTIVE: Determine the influence of the anatomical features and sizes of the lateral pocket with a defect on the choice of surgical access and the quality of the performed plastics. MATERIAL AND METHODS: A retrospective analysis of computed tomograms of 38 patients who underwent surgical treatment at the Burdenko National Medical Research Center for Neurosurgery of the Ministry of Health of Russia about defects of the skull base in the area of the lateral pocket of the sphenoid sinus. The patients were divided into three groups depending on the approach used (the 1st group), the recurrence rate (the 2nd group), and the characteristics of intraoperative visualization of the defect (the 3rd group). RESULTS: There were no statistically significant differences in anatomical features in patients who underwent trans-pterygoid and transsphenoidal approaches, as well as in patients of the 2nd group. Patients of the 3rd group (with visualization features) showed statistically significant differences between the distance from the defect to the VR line (p=0.007). In patients with good visualization of the defect using direct optics, this distance was shorter than in patients in whom the defect was visualized with an angled endoscope. No other anatomical differences were noted. CONCLUSIONS: The anatomical features of the lateral pocket structure (type of pneumatization, size and volume) did not affect the choice of access to the defect and the frequency of recurrence. When comparing the approaches, it was noted that the trans-pterygoid access, providing direct visualization of defects, minimizes the risk of recurrence in the postoperative period. An objective anatomical indicator for choosing an access to the defects of the lateral pocket can be the distance from the defect to the VR line: at a distance of more than 0.7 cm, it is advisable to perform a trans-pterygoid approach; at a distance of less than 0.7 cm, it is possible to achieve direct visualization of the defect and perform high-quality plastic surgery with a transsphenoidal access.

[Orbital venous varices: modern diagnostic methods and differential diagnosis]. / Orbital'nyi venoznyi varikoz: sovremennye metody diagnostiki i differentsial'nyi diagnoz.

OBJECTIVE: To study the possibility of the modern CT and MRI methods in diagnostics of the orbital venous varices (OVV), discover the special characteristics of these lesions concerning their hemodynamic and differential diagnosis with other orbital lesions. MATERIAL AND METHODS: In the period from 2012 to 2019 ten patients with OVV were evaluated. Four of them were men, three - women and three - children (boys aged 7, 10, and 12 years). Age of the patients varied from 7 to 75 years old (mediana - 34).CT was performed on 9 patients using low dose protocol with injecting the contrast in standard position (supine) and in the prone position. CT-angiography was performed on 3 patients and CT-perfusion - 5 patients which allowed the assessment of the blood supply and quantitative lesions hemodynamic by calculating blood flow (BFOVV), blood volume (BVOVV) and mean transit time (MTTOVV).MRI with contrast injection and Fat Sat technology was performed on 9 patients, 3 of them were both in the supine and prone positions. 4 patients were evaluated by bolus MR-angiography (TRICKS). RESULTS: The majority of the OVV was localized in the medial compartments and apex of the orbit. Left sided lesions were found in 6 cases, right - 3. One patient had both sided OVV. In one of the cases in 10-year-old child, we revealed malformation of the Galen vein associated with bilateral varicose enlargement of the intraorbital veins (secondary OVV).In CT studies all of the lesions enhanced after the contrast injection. When the patients were study in the prone position, all lesions were enlarging; which lead to the diagnosis of OVV. CT-angiography (venous blood flow) proved vascular nature of the lesions. While studying the quantitative lesion hemodynamic by the CT perfusion technology, it was discovered, that OVV tend to have high blood volume (BVOVV=19.61±3.23(ml/100g) and high blood flow (BFOVV= 60.87±8.11) and the prolongation of mean transit time (MTTOVV=19.23±3.07). Normal parameters measured in white matter were CBVN=1.37±0.69(ml/100g), CBFN=38.4±4.31(ml/100g/min), MTTN=2.89±0.44s.In MRI studies all the lesions had iso-hypointense MR-signal on T1- and hyperintense on T2-images. The pattern of contrast enhancement was inhomogeneous, however reaching homogeneity after some time. TRICKS MR-angiography was more sensitive than CT-angiography (venous phase). Moreover, the absence of radiation exposition was an additional advantage of the MR-venography. CONCLUSION: Diagnosis of orbital vascular pathology requires an understanding of the classification of vascular lesions, the integration of the patient's medical history with epidemiological data, as well as a through analysis of the results of instrumental diagnostic methods. CT or MRI, including scanning in the prone position, as well as minimally invasive CT- and MR-TRICKS-angiography and ophthalmological studies of the patient, determine a comprehensive approach to the diagnosis and selection of adequate treatment for orbital venous varices.In the differential diagnosis of OVV with other neoplasms of the orbit, we recommend CT-perfusion study with determine the quantitative characteristics of its hemodynamics.