BackgroundFlow diversion (FD) has emerged as superior minimally invasive therapy for cerebral aneurysms. However, aneurysms of small peripheral vessel segments have not yet been adequately treatable. More specifically, currently established devices necessitate large microcatheters which impede atraumatic maneuvering. The Silk Vista Baby (SVB), a novel flow diverter, offers the as yet unique feature of deliverability via a 0.017 inch microcatheter. This study reports our first experience with the SVB in challenging intracranial vessels employing a vessel-specific tailored microcatheter strategy.Materials and methods25 patients (27 aneurysms) were prospectively included. A total of 30 SVBs were employed, predominantly targeting demanding aneurysms of the anterior communicating artery complex. The efficacy of the FD was assessed using two-dimensional vector-based perfusion and conventional digital subtraction angiography (DSA) after implantation and at the first follow-up at 3 months. The first follow-up was available in 22 patients.ResultsAll devices were implanted without technical or clinical complications. Eleven treatments were performed using the recommended Headway 17. In 14 interventions the even more maneuverable Excelsior SL10 was used, which was previously tried and tested for safety ’in vitro’ as an alternative delivery system. Aneurysmal influx was strongly reduced after implantation. All parent vessels remained patent. 17/27 aneurysms were completely occluded at first follow-up (∼2.7 months), 6/27 aneurysms showed decreased influx or delayed washout and one remained unchanged. In three cases follow-up DSAs are remaining.ConclusionsSVB provides enhanced controllability in vulnerable segments beyond the circle of Willis. Smaller variants (2.25 mm and 2.75 mm) can safely be implanted via the superiorly navigable Excelsior SL10. Hence, the SVB represents the next evolutionary step in minimally invasive treatment of cerebral aneurysms.

Conventional surfactant proteins (A, B, C, and D) are important players of the innate immunity in the central nervous system and serve as effective regulators of cerebrospinal fluid rheology, probably being involved in clearance of detrimental metabolites like beta-amyloid and phospho-tau. Recently, a novel surfactant protein, SP-G, was described in kidneys and peripheral endocrine and exocrine glands. So far, its presence and possible functions in the central nervous system are unknown. Therefore, our study aimed to elucidate the presence of SP-G in the brain and its concentration in normal and pathologic samples of cerebrospinal fluid in order to gain first insight into its regulation and possible functions. A total of 121 samples of human cerebrospinal fluid (30 controls, 60 hydrocephalus patients, 7 central nervous system infections, and 24 brain hemorrhage patients) and 21 rat brains were included in our study. CSF samples were quantified using a commercially available ELISA system. Results were analyzed statistically using SPSS 22, performing Spearman Rho correlation and ANOVA with Dunnett's post hoc analysis. Rat brains were investigated via immunofluorescence to determine SP-G presence and colocalization with common markers like aquaporin-4, glial fibrillary acidic protein, platelet endothelial adhesion molecule 1, and neuronal nuclear antigen. SP-G occurs associated with brain vessels, comparable to other conventional SPs, and is present in a set of cortical neurons. SP-G is furthermore actively produced by ependymal and choroid plexus epithelium and secreted into the cerebrospinal fluid. Its concentrations are low in control subjects and patients suffering from aqueductal stenosis, higher in normal pressure hydrocephalus (p < 0.01), and highest in infections of the central nervous system and brain hemorrhage (p < 0.001). Interestingly, SP-G did correlate with total CSF protein in patients with CNS infections and hemorrhage, but not with cell count. Based on the changes in CSF levels of SP-G in hydrocephalus, brain hemorrhage, and CNS infections as well as its abundance at CSF flow-related anatomical structures closely associated with immunological barrier systems, importance for CSF rheology, brain waste clearance, and host defense is assumable. Thus, SP-G is a potential new CSF biomarker, possibly not only reflecting aspects of CNS innate immune responses, but also rheo-dynamically relevant changes of CSF composition, associated with CSF malabsorbtion. However, further studies are warranted to validate our findings and increase insight into the physiological importance of SP-G in the CNS.

Background: Hemodynamic therapy with Flow-Diverters has become a fundamental option for treatment of cerebral aneurysms. A major obstacle of Flow-Diverters is the comparatively stiff microcatheter required for implantation. Consequentially, maneuverability is limited and primary catheterization of peripheral targets may be difficult or even futile in challenging vascular anatomies. To overcome this, a highly navigable microcatheter must be used to attain the desired vascular segment, followed by a hardly controllable exchange-maneuver via a long microwire, involving a high risk for wire-perforation. Our study aimed to investigate the value of low-profile stentretrievers as a railway for introduction of the required microcatheter, which allows to maintain a stable endovascular position and reduce the risk for procedural vessel injury. Methods: 14cases (8females, mean-age 59y) of Flow-Diverter-Implantation requiring the use of a low-profile stentretriever were reviewed. All cases featured a challenging vascular anatomy. After micro-catheterization of the desired segment, the stent-retriever was carefully deployed as an anchor in a secure, distal location. In all cases a pREset/LITE-stent-retriever was used for introduction of the equipment required for implantation. Results: In all cases the anchoring-maneuver was performed without technical complications. The stent-retrievers maintained a stable position after deployment in all situations. No potential traumatic sudden movements of the microcatheter occurred. No procedure-related perforations, dissections or vasospasms were observable during the interventions or their aftermath. Conclusions: In our experience the stent-retriever-anchoring-maneuver represents a potentially essential and safe amendment for flow diverter treatment in technically challenging situations.

Background and Purpose: Low-profile flow diverter stents (FDS) quite recently amended peripheral segments as targets for hemodynamic aneurysm treatment; however, reports on outcomes, especially later than 3 months, are scarce. This study therefore reports our experience with the novel silk vista baby (SVB) FDS and respective outcomes after 8 and 11 months with special respect to specific adverse events.Materials and Methods: Forty-four patients (mean age, 53 years) harboring 47 aneurysms treated with the SVB between June 2018 and December 2019 were included in our study. Clinical, procedural, and angiographic data were collected. Follow-ups were performed on average after 3, 8, and 11 months, respectively. Treatment effect was assessed using the O'Kelly Marotta (OKM) grading system.Results: Overall, angiographic follow-ups were available for 41 patients/45 aneurysms. Occlusion or significant reduction in aneurysmal perfusion (OKM: D1, B1–B3 and A2–A3) was observed in 98% of all aneurysms after 8 months. Only 2% of the treated aneurysms remained morphologically unaltered and without an apparent change in perfusion (OKM A1). Adverse events in the early post-interventional course occurred in seven patients; out of them, mRS-relevant morbidity at 90 days related to FDS treatment was observable in two patients. One death occurred in the context of severe SAH related to an acutely ruptured dissecting aneurysm of the vertebral artery.Conclusion: The SVB achieves sufficient occlusion rates of intracranial aneurysms originating from peripheral segments, which are comparable to prior established conventional FDS with acceptably low complication rates. However, alteration of a hemodynamic equilibrium in distal localizations requires special attention to prevent ischemic events.

Our purpose was to analyze associations between apparent diffusion coefficient (ADC) histogram analysis parameters and histopathologicalfeatures in head and neck squamous cell carcinoma (HNSCC).The study involved 32 patients with primary HNSCC. For every tumor, the following histogram analysis parameters were calculated: ADCmean, ADCmax, ADCmin, ADCmedian, ADCmode, P10, P25, P75, P90, kurtosis, skewness, and entropy. Furthermore, proliferation index KI 67, cell count, total and average nucleic areas were estimated. Spearman's correlation coefficient (p) was used to analyze associations between investigated parameters.In overall sample, all ADC values showed moderate inverse correlations with KI 67. All ADC values except ADCmax correlated inversely with tumor cellularity. Slightly correlations were identified between total/average nucleic area and ADCmean, ADCmin, ADCmedian, and P25.In G1/2 tumors, only ADCmode correlated well with Ki67. No statistically significant correlations between ADC parameters and cellularity were found.In G3 tumors, Ki 67 correlated with all ADC parameters except ADCmode. Cell count correlated well with all ADC parameters except ADCmax. Total nucleic area correlated inversely with ADCmean, ADCmin, ADCmedian, P25, and P90.ADC histogram parameters reflect proliferation potential and cellularity in HNSCC. The associations between histopathology and imaging depend on tumor grading.

BACKGROUND: Meningiomas are the most frequently diagnosed intracranial masses, oftentimes requiring surgery. Especially procedure-related morbidity can be substantial, particularly in elderly patients. Hence, reliable imaging modalities enabling pretherapeutic prediction of tumor grade, growth kinetic, realistic prognosis, and—as a consequence—necessity of surgery are of great value. In this context, a promising diagnostic approach is advanced analysis of magnetic resonance imaging data. Therefore, our study investigated whether histogram profiling of routinely acquired postcontrast T1-weighted images is capable of separating low-grade from high-grade lesions and whether histogram parameters reflect Ki-67 expression in meningiomas. MATERIAL AND METHODS: Pretreatment T1-weighted postcontrast volumes of 44 meningioma patients were used for signal intensity histogram profiling. WHO grade, tumor volume, and Ki-67 expression were evaluated. Comparative and correlative statistics investigating the association between histogram profile parameters and neuropathology were performed. RESULTS: None of the investigated histogram parameters revealed significant differences between low-grade and high-grade meningiomas. However, significant correlations were identified between Ki-67 and the histogram parameters skewness and entropy as well as between entropy and tumor volume. CONCLUSIONS: Contrary to previously reported findings, pretherapeutic postcontrast T1-weighted images can be used to predict growth kinetics in meningiomas if whole tumor histogram analysis is employed. However, no differences between distinct WHO grades were identifiable in out cohort. As a consequence, histogram analysis of postcontrast T1-weighted images is a promising approach to obtain quantitative in vivo biomarkers reflecting the proliferative potential in meningiomas.

PURPOSE: Diffusion weighted imaging (DWI) quantifies motion of hydrogen nuclei in biological tissues and hereby has been used to assess the underlying tissue microarchitecture. Histogram-profiling of DWI provides more detailed information on diffusion characteristics of a lesion than the standardly calculated values of the apparent diffusion coefficient (ADC)—minimum, mean and maximum. Hence, the aim of our study was to investigate, which parameters of histogram-profiling of DWI in primary central nervous system lymphoma can be used to specifically predict features like cellular density, chromatin content and proliferative activity. PROCEDURES: Pre-treatment ADC maps of 21 PCNSL patients (8 female, 13 male, 28–89 years) from a 1.5T system were used for Matlab-based histogram profiling. Results of histopathology (H&E staining) and immunohistochemistry (Ki-67 expression) were quantified. Correlations between histogram-profiling parameters and neuropathologic examination were calculated using SPSS 23.0. RESULTS: The lower percentiles (p10 and p25) showed significant correlations with structural parameters of the neuropathologic examination (cellular density, chromatin content). The highest percentile, p90, correlated significantly with Ki-67 expression, resembling proliferative activity. Kurtosis of the ADC histogram correlated significantly with cellular density. CONCLUSIONS: Histogram-profiling of DWI in PCNSL provides a comprehensible set of parameters, which reflect distinct tumor-architectural and tumor-biological features, and hence, are promising biomarkers for treatment response and prognosis.

Our purpose was to analyze possible associations between histogram analysis parameters of dynamic contrast-enhanced magnetic resonance imaging DCE MRI and histopathological findings like proliferation index, cell count and nucleic areas in head and neck squamous cell carcinoma (HNSCC).30 patients (mean age 57.0 years) with primary HNSCC were included in the study. In every case, histogram analysis parameters of Ktrans, Ve, and Kep were estimated using a mathlab based software. Tumor proliferation index, cell count, and nucleic areas were estimated on Ki 67 antigen stained specimens. Spearman's non-parametric rank sum correlation coefficients were calculated between DCE and different histopathological parameters.KI 67 correlated with Ktrans min (p = −0.386, P = 0.043) and s Ktrans skewness (p = 0.382, P = 0.045), Ve min (p = −0.473, P = 0.011), Ve entropy (p = 0.424, P = 0.025), and Kep entropy (p = 0.464, P = 0.013). Cell count correlated with Ktrans kurtosis (p = 0.40, P = 0.034), Ve entropy (p = 0.475, P = 0.011). Total nucleic area correlated with Ve max (p = 0.386, P = 0.042) and Ve entropy (p = 0.411, P = 0.030).In G1/2 tumors, only Ktrans entropy correlated well with total (P =0.78, P =0.013) and average nucleic areas (p = 0.655, P = 0.006). In G3 tumors, KI 67 correlated with Ve min (p = −0.552, P = 0.022) and Ve entropy (p = 0.524, P = 0.031). Ve max correlated with total nucleic area (p = 0.483, P = 0.049). Kep max correlated with total area (p = −0.51, P = 0.037), and Kep entropy with KI 67 (p = 0.567, P = 0.018).We concluded that histogram-based parameters skewness, kurtosis and entropy of Ktrans, Ve, and Kep can be used as markers for proliferation activity, cellularity and nucleic content in HNSCC. Tumor grading influences significantly associations between perfusion and histopathological parameters.