The safety and efficacy of double microcatheter technique in small and tiny ruptured aneurysms: A single center study

Objective

Double microcatheter technique (dMC) can be the alternative to Single microcatheter technique (sMC) for challenging cases, but there is lack of studies comparing dMC to sMC especifically for small ruptured aneurysms. Our objective was to compare the safety and efficacy of dMC to sMC in treating small (≤5 mm) and tiny (≤3 mm) ruptured aneurysms.

Methods

This study focused on 91 out of 280 patients who had ruptured aneurysms and underwent either single or double microcatheter coil embolization. These patients were treated with either single or double microcatheter coil embolization. We divided the patients into two groups based on the procedural method and evaluated clinical features and outcomes. Subgroup analyses were conducted specifically for tiny aneurysms, comparing the two methods, and within the dMC group, we also examined whether the aneurysm was tiny or not. In addition, univariate logistic regression analysis was performed to assess the impact of coil packing density.

Results

The mean values for most outcome measures in the dMC group were higher than those in the sMC group, but these differences did not reach statistical significance (coil packing density, 45.739% vs. 39.943%; procedural complication, 4.17% vs. 11.94%; recanalization, 8.3% vs. 10.45%; discharge discharge modified Rankin Scale (mRS), 1.83 vs. 1.97). The comparison between tiny aneurysms and other sizes within the dMC group did not reveal any significant differences in terms of worse outcomes or increased risk. The only factor that significantly influenced coil packing density in the univariate logistic regression analysis was the size of the aneurysm (OR 0.309, 95% CI 0.169-0.566, p=0.000).

Conclusions

The dMC proved to be a safe and viable alternative to the sMC for treating small ruptured aneurysms in challenging cases.

Misdiagnosis of Spontaneous Intracranial Hypotension Presenting as Acute Mental Deterioration Caused by Unilateral Acute Subdural Hematoma: Case Report

Spontaneous intracranial hypotension (SIH) is usually a benign disease which mostly present as orthostatic headache and resolves by conservative treatment or epidural blood patch. However, in severe cases large subdural hematoma or brain caudal herniation can progress to brain herniation and neurologic complications. We introduce a rare case of SIH which presented as acute mental deterioration with unilateral acute subdural hematoma. A 60 years old female visited to emergency room for stuporous mental change and unilateral acute subdural hematoma. Decompressive craniectomy and hematoma removal was performed to release brain herniation and increased intracranial pressure. There was temporary improvement of consciousness, but sustained leakage of cerebrospinal fluid (CSF) and caudal brain herniation worsened patient's condition. After recognizing that CSF leakage and hypovolemia was the underlying disease, emergent epidural blood patch and early cranioplasty was performed. After treatment CSF volume was normalized and patient recovered completely without neurologic deficits. Acute mental deterioration with unilateral subdural hematoma is a rare presentation for SIH. Treatment strategy for subdural hematoma with concomitant SIH patients, should be planned carefully with concerns to CSF hypovolemia and intracranial pressure.

Practical 12.5-Gb/s, 12.5-GHz spaced ultra-dense WDM PON

We report a practical 12.5-Gb/s, 12.5-GHz-spaced ultra-dense wavelength-division-multiplexed passive optical network (UD-WDM PON). For the cost-effectiveness, we implement the downstream links by using electro-absorption modulated lasers (EMLs) in the 4-level pulse amplitude modulation (4PAM) format and PIN receivers, and the upstream links by using reflective semiconductor optical amplifiers (RSOAs) modulated in the quadrature phase-shift-keying (QPSK) format and low-cost self-homodyne receivers. To further enhance its cost-effectiveness, we also utilize an optical frequency comb generator, instead of a large number of wavelength-selected lasers, to provide the seed light for these colorless RSOAs. We optimize the operating conditions of the EMLs and RSOAs to maximize the power margins in the presence of the crosstalk arising from closely spaced neighboring channels and the inter-symbol interference (ISI) caused by the narrow passband of the cascaded arrayed-waveguide gratings (AWGs) as well as the limited modulation bandwidths of RSOAs. The experimental results show that we can secure the power margins of >2.5 dB for both upstream and downstream links of the proposed UD-WDM PON.

Transmission of 40-Gb/s QPSK upstream signal in RSOA-based coherent WDM PON using offset PDM technique

We demonstrate the 40-Gb/s upstream transmission in the 60-km reach wavelength-division-multiplexed passive optical network (WDM PON) implemented by using directly modulated reflective semiconductor optical amplifiers (RSOAs) and self-homodyne receivers. It is difficult to operate the RSOA at 40 Gb/s due to its limited modulation bandwidth. To overcome this problem and generate 40-Gb/s upstream signal, we utilize the quadrature phase-shift-keying (QPSK) format and the offset polarization-division-multiplexing (PDM) technique. For this purpose, we install two RSOAs at each ONU and provide the seed light for these RSOAs by polarization-multiplexing the outputs of two lasers with a small frequency offset (20 GHz). This frequency offset is used to separate the polarization-multiplexed seed light by using a simple delay-line interferometer (DLI), instead of the polarization-beam splitter and polarization controller, at the ONU. The separated seed light is modulated by each RSOA at 20 Gb/s in the QPSK format, and then combined again by the DLI before sent back to the central office (CO). The results show that this WDM PON can support the transmission of 40-Gb/s channels spaced at 50 GHz over 60 km without using any remote optical amplifiers.

Correlation-based OTDR for in-service monitoring of 64-split TDM PON

We demonstrate that the correlation-based optical time domain reflectometer (OTDR) can be used for the in-service monitoring of the 64-split time-division-multiplexed passive optical network (TDM PON). To achieve this objective, we superimpose a pseudo noise (PN) sequence having a modulation depth of ~40% to the downstream signal and utilize it for the correlation detection. However, the use of such a large PN sequence can seriously deteriorate the performance of the downstream receiver. Thus, we apply 8B/10B encoding to the downstream signal, and then filter out the PN sequence at the downstream receiver by using a high-pass filter. As a result, the power penalty caused by the use of a large PN sequence is reduced to an acceptable level (<3 dB), while the dynamic range of this correlation-based OTDR is increased to ~30 dB. We then evaluate the performance of the proposed OTDR in the fiber link similar to the optical distribution network of the 64-split TDM PON. The results show that this OTDR can detect both the reflective and non-reflective events occurred in the feeder fiber as well as the reflective events in the drop fibers even in the 64-split TDM PON.

Effect of substrate and metal layer deformation on recording characteristics of recordable discs with metallic thin film

Compact disc-recordable (CD-R) and digital versatile disc-recordable (DVD-R) discs were fabricated with a polycarbonate substrate, metallic thin film, organic buffer layer, reflective layer, and protective layer. Recording characteristics of a CD-R disc at various recording speeds, from 1x to 8x, were evaluated, and the deformation shapes of each layer after recording were investigated and compared with the DVD-R disc. The relationship between deformation and recording characteristics was studied and interpreted by numerical calculation. The modulated amplitude of recorded signals is increased as the recording speed increases, owing to the increase in decomposition of the buffer layer, which resulted from the localization of heat on the metallic thin film. On the basis of these results, a DVD-R disc with metallic thin film is expected to have better recording characteristics at a higher recording speed.

Co-cultivation of CD4+ and CD8+ human T-cells leads to the appearance of CD4 cells expressing CD8 through de novo synthesis of the CD8 alpha-subunit

The appearance of a population of dual-staining CD4+CD8+ cells in human T-lymphocyte cultures has been reported by various authors, including our own observation that they are always seen in simple phytohaemagglutinin-stimulated cultures from several different donors. The purpose of the present study was to investigate factors involved in the dual-staining (DS) phenotype, and to clarify some apparent inconsistencies between published observations. Our findings can be summarised as follows. 1. A population of DS CD4+CD8+ cells always appears in PHA-stimulated T-cell cultures if they contain both CD4 and CD8 subsets. The incidence of DS cells is related to PHA concentration, but other factors are involved since DS cells are not seen in PHA-stimulated cultures of purified CD4+ or CD8+ cells. Stimulation with PHA is not a prerequisite since very similar results are seen with ConA. 2. Direct physical contact between CD4+ and CD8+ cells is required for the appearance of the DS phenotype; soluble factors alone, including IL-4, appear nor to be responsible. 3. The DS phenotype in these conditions is always CD4+ cells weakly expressing CD8 and is a consequence of de novo synthesis of the CD8alpha molecule by the CD4+ cells.

Sulfonated polystyrene as a new gradient-index medium for light-focusing elements

We have discovered that the sulfonation of polystyrene can form a gradient-index medium useful for lightfocusing purposes. We found that the refractive index of sulfonated polystyrene varies with the degree of sulfonation and that the refractive index of the fully sulfonated polystyrene decreased by approximately 0.06 at 0.633 microm from that of pure polystyrene.