Number Of Segments Research Articles

Hidden blood loss and risk factors after percutaneous endoscopic transforaminal lumbar interbody fusion

PurposeIn this study, we aimed to assess the occurrence of hidden blood loss (HBL) and its associated risk factors in patients with lumbar degenerative diseases who underwent percutaneous endoscopic transforaminal lumbar interbody fusion (Endo-TLIF).MethodsSex, age, height, weight, body mass index, and medical history including hypertension, diabetes, and osteoporosis were recorded. The duration of symptoms, preoperative lumbar subcutaneous fat tissue thickness (measured using midsagittal T2-weighted magnetic resonance imaging), lumbar disc degeneration grade, and other basic patient information were also documented. The levels of fibrinogen, activated partial thromboplastin time, prothrombin time, thrombin time, and platelet count as well as the pre- and postoperative hematocrit and hemoglobin levels were collected. In addition, the number of fusion levels, surgical time, and intraoperative blood loss were recorded. Total blood loss (TBL) was calculated using the gross formula, and HBL was calculated based on the TBL and visible blood loss. The risk factors were analyzed using single-factor correlation and multivariate linear regression analyses.ResultsOf the 83 patients, there were 42 males and 41 females. Hypertension (P = 0.003), fusion level (P < 0.001), and surgery time (P < 0.001) were significantly correlated with HBL via a single-factor correlation analysis. Multiple linear regression analysis showed that the fusion level (P < 0.001) and surgery time (P < 0.001) were independent risk factors for HBL.ConclusionIn patients with lumbar degenerative diseases treated with Endo-TLIF, HBL accounts for a large proportion of TBL. A large number of fusion segments and prolonged operation time are risk factors for increased perioperative HBL during Endo-TLIF. Increased attention should be paid to the presence of HBL to ensure the safety of perioperative patients.

Experimental study and numerical simulation of precast segmental bridge columns with different design details for high seismic zones

In this study, five 1/3-scale bridge column specimens are experimentally and numerically investigated, which includes one cast-in-place (CIP) reference and four precast segmental columns with different design details. The four precast segmental bridge columns are of the same design details in terms of dimension and mild reinforcement, while different number of segments, various full-length connection rebar grades, presence of prestressing force, and two types of shear keys are compared. Seismic performance of the five specimens is compared under the same quasi-static cyclic loading protocol. Based on the experimental results, the precast segmental specimen solely using mild reinforcement exhibits similar seismic performance to the CIP reference, while segmentation slightly reduces post-yield stiffness and dissipated energy but increases the self-centering capability. Implementation of prestressing force significantly improves the self-centering capability of the columns, and higher grades of steel also increase the overall strength of the columns. Less number of segments in the column will lead to better structural integrity with smaller joint opening widths and higher energy dissipation capacity. A new finite element model is also proposed, and maximum deviation from test results is less than 2% in terms of stiffness and peak strength. This demonstrates that the Parallel material for rebar modeling and ZeroLength element for joint interface (including bond–slip behavior of rebar) simulation are both effective.

Estimating realized relatedness in free-ranging macaques by inferring identity-by-descent segments

Biological relatedness is a key consideration in studies of behavior, population structure, and trait evolution. Except for parent-offspring dyads, pedigrees capture relatedness imperfectly. The number and length of identical-by-descent DNA segments (IBD) yield the most precise relatedness estimates. Here, we leverage different methods for estimating IBD segments from low-depth whole genome resequencing data to demonstrate the feasibility and value of resolving fine-scaled gradients of relatedness in free-living animals. Using primarily 4 to 6× depth data from a rhesus macaque (Macaca mulatta) population with long-term pedigree data, we show that we can infer the number and length of IBD segments across the genome with high accuracy even at 0.5× sequencing depth. In line with expectations based on simulation, the resulting estimates demonstrate substantial variation in genetic relatedness within kin classes, leading to overlapping distributions between kin classes. By comparing the IBD-based estimates with pedigree and short tandem repeat-based methods, we show that IBD estimates are more reliable and provide more detailed information on kinship. The inferred IBD segments also identify cryptic genetic relatives not represented in the pedigree and reveal elevated recombination rates in females relative to males, which enables the majority of close maternal and paternal kin to be distinguished with genotype data alone. Our findings represent a breakthrough in the ability to study the predictors and consequences of genetic relatedness in natural populations, contributing to our understanding of a fundamental component of population structure in the wild.

The impact of matrix viscosity on the mechanical behavior of fiber reinforced composites

AbstractThe influence of matrix viscosity on the mechanical behavior of fiber reinforced composites was investigated in this paper. The glass fiber fabric was selected as reinforcement and the mixed solution composed of resin, curing agent and different viscosity of diluent was selected as matrix. The composites was fabricated by vacuum‐assisted resin infusion (VARI). The influence of matrix viscosity on bending, impact and creep properties of composites were studied by varying the mass fraction of 1,4‐butanediol diglycidyl ether (BDDGE) diluent, the least square fitting was used to fit the experimental result. The mathematical model for characterizing the relationship between the matrix viscosity and the bending strength was established, and the mass fraction of BDDGE diluent based on the optimal bending property was obtained. The failure mechanisms were analyzed by analyzing fiber reinforced composites properties, reaction principles and fracture morphologies. Result shows that the epoxy groups within the viscosity undergo a ring‐opening reaction to integrate the cross‐linking network structure of the epoxy resin. However, an excessive amount of diluent will result in an increase of number of flexible chain segments, which initially enhancing the mechanical properties of the specimens before causing a subsequent decline. The mathematical model was substantiated by experiment, which reveals that the viscosity is 185.3 mPa·s for the optimal bending properties.Highlights The bending strength and modulus reached the maximum at a viscosity of 180 mPa·s The creep curves demonstrate progressive damage and minute deformation. The ring‐opening reaction occurs with two oxygen atoms in the diluent BDDGE. The matrix viscosity of BDDGE diluent is 185.3 mPa·s for the optimal bending properties.

A nomogram for postoperative pain relief in patients with osteoporotic vertebral compression fracture treated with polymethylmethacrylate bone cement

Osteoporotic vertebral compression fractures (OVCFs) can be painful. Percutaneous kyphoplasty (PKP) aims at strengthening the vertebra and reducing pain, but efficacy can vary among patients. The purpose of this study was to establish a risk prediction model for pain relief following PKP in patients with OVCF. This retrospective study included 208 (training set) and 54 (validation set) OVCF patients who underwent bone cement treatment between January 2018 and October 2023. Based on postoperative VAS scores, patients were divided into two groups (0–2 and 3–6). Univariable and multivariable logistic regression identified significant factors affecting VAS scores, leading to the creation of a nomogram model. Internal validation was performed using the bootstrap method. The model’s performance and clinical value were evaluated using the area under the receiver operating characteristic curve (AUC), decision curve analysis (DCA), and calibration curves. Four predictors were identified: number of segments, PMMA dose, comorbidities, and central nervous system (CNS) medications. The AUC, DCA, and calibration curves demonstrated good model discrimination and accuracy. The clinical impact plot highlighted the model’s practical value. We developed and validated an intuitive nomogram model for predicting a postoperative VAS score ≤ 2, reflecting therapeutic efficacy in OVCF patients treated with PMMA. The model could be used for a more careful selection of patients suitable for PKP and who would benefit the most from PKP. The other patients should at least be advised of the risk of suboptimal pain control or directed toward other treatments.

The dynamics of initiation in caregiver-child conversational interactions.

We investigated the dynamics of communicative initiation in infant-caregiver interactions across ages and language abilities. Analyses of 228 Language ENvironment Analysis (LENA) recordings from 141 Korean adult-child dyads (60 girls; aged 7-30 months) replicated the initiator effect reported in North American populations. This effect, demonstrated by longer utterances, more frequent speech, and shorter response times in self-initiated interactions for both children and adults, suggests potential cross-cultural consistency in this conversational dynamic and remained consistent across ages in most conversational measures. A focused analysis of 13-14 month-olds (N = 40) and their K-CDI scores revealed that the initiator effect in segment duration and number persisted across most vocabulary percentiles. Additionally, nuanced findings indicated that caregivers increased their input frequency and adjusted segment duration in adult-initiated conversations in tandem with children's higher receptive abilities. The robustness of the initiator role across cultures, ages, and vocabulary abilities points to a fundamental aspect of human communication.

Reduction of ischemic time using the pull-through technique for scapular free flap.

Current scapular free flap (SFF) harvest in mandibular reconstruction often requires repositioning, hindering simultaneous harvest and resection and potentially increasing ischemic time. This study evaluated the efficacy of the pull-through technique (PTT) for SFF harvest, aiming to reduce ischemic time during mandibular segmental resection. A retrospective analysis was conducted on 24 patients who underwent mandibular reconstruction using SFF at two maxillofacial surgery departments between January 2015 and May 2022. In total, 13 patients received PTT, while the remaining 11 underwent non-PTT. Demographic and clinical data were collected, including age, sex, diagnosis, resected mandibular segments, operative time, and ischemic time. Statistical analysis was performed to compare these variables between the PTT and non-PTT groups. The study found no significant differences between the groups in terms of age, sex, diagnosis, number of resected segments, or total operative time. However, ischemic time was significantly shorter in the PTT group than in the non-PTT group. PTT also allowed for minimal position changes during surgery compared with non-PTT. Our study investigated the impact of the PTT on SFF reconstruction during mandibular segmental resection. We found that utilizing PTT-SFF significantly reduced ischemic time compared with the traditional method. This technique offers a potential advantage by facilitating stable blood flow visualization and potentially improving flap viability. Not applicable.

2D Embeddings of Multi-dimensional Partitionings.

Partitionings (or segmentations) divide a given domain into disjoint connected regions whose union forms again the entire domain. Multi-dimensional partitionings occur, for example, when analyzing parameter spaces of simulation models, where each segment of the partitioning represents a region of similar model behavior. Having computed a partitioning, one is commonly interested in understanding how large the segments are and which segments lie next to each other. While visual representations of 2D domain partitionings that reveal sizes and neighborhoods are straightforward, this is no longer the case when considering multi-dimensional domains of three or more dimensions. We propose an algorithm for computing 2D embeddings of multi-dimensional partitionings. The embedding shall have the following properties: It shall maintain the topology of the partitioning and optimize the area sizes and joint boundary lengths of the embedded segments to match the respective sizes and lengths in the multi-dimensional domain. We demonstrate the effectiveness of our approach by applying it to different use cases, including the visual exploration of 3D spatial domain segmentations and multi-dimensional parameter space partitionings of simulation ensembles. We numerically evaluate our algorithm with respect to how well sizes and lengths are preserved depending on the dimensionality of the domain and the number of segments.

Attempt to Improve MIP Image of Cerebrovascular MRA by Subtraction Method: Efficient Acquisition of Mask Images Using Segmented TOF and Compressed Sensing

The aim of this study was to investigate imaging conditions that allow for the rapid acquisition of mask images used in the subtraction method, one of the depiction improvement methods for brain magnetic resonance angiography, by employing compressed sensing (CS) combined with segmented time-of-flight (TOF). The experiment was performed on healthy volunteers using 3.0T-MRI. We examined the blood flow signal suppression effects in arteries and veins at different numbers of segments. We determined the flip angle at which the signal value of fat in the mask image became equivalent to that in the angio image. We visually assessed the impact of mask images with varying CS factors on subtraction images and determined the optimal CS factor. Effective blood flow signal suppression in arteries and veins was achieved with segment numbers of 12 or fewer, and a flip angle of 18° resulted in equivalent fat signal values. Even with a CS factor set to its maximum value of 12, no degradation in image quality was observed in the maximum intensity projection images. Using segmented TOF with CS, optimal imaging conditions for acquiring mask images for the subtraction method were determined to be segment number 9, flip angle 18°, and CS factor 12.

On General Sum‐Connectivity Index and Number of Segments of Fixed‐Order Chemical Trees

On General Sum‐Connectivity Index and Number of Segments of Fixed‐Order Chemical Trees

Results of one-year follow-up of patients with severe myocarditis associated with COVID-19 on glucocorticoid therapy

The aim of the study – to investigate the effectiveness and safety of glucocorticoid therapy in patients with severe myocarditis associated with COVID-19.Materials and methods. The results are based on data obtained from 72 patients with severe acute myocarditis (AM) and heart failure (HF) with reduced left ventricular ejection fraction (LVEF ≤ 40 %). Patients were divided into two groups: the group 1 included 34 patients with AM, who had a documented history of coronavirus disease ≤ 3 months before the onset of clinical symptoms of AM; the group 2 consisted of 38 patients with AM, who had no history of coronavirus disease. All patients received optimal therapy for heart failure during all period of follow-up and immunosuppressive therapy with glucocorticoids (GKs) within first 6 months from the onset of AM. Patients underwent for echocardiography with speckle tracking and cardiac magnetic resonance (CMR). The studies were conducted three times: in the first month from the onset of clinical symptoms of myocarditis, after 6 months, and after 12 months of observation.Results and discussion. After 6 months of follow-up, improvements in the structural and functional state of the heart were observed in both groups, with group 1 showing greater increases in LVEF and LGSS by 13.1 % and 22.2 %, respectively (p<0.05). Additionally, group 1 exhibited a reduction in the number of LV segments affected by inflammatory changes and the total number of damaged segments by 28.4 % and 18.3 %, respectively, compared to group 2 (p<0.05–0.001). After 12 months results of CMR demonstrated significantly less myocardial damage in group 1 compared to group 2: the total number of LV segments affected by inflammation and/or fibrosis was 39.0 % lower (p<0.001). The most common complications of GKs therapy after 6 months were obesity (13.88 %) and leukocytosis (12.50 %), while hypokalemia occurred in 6.94 % of cases. Complications such as arterial hypertension, hyperglycemia, functional hypercortisolism, and myalgia were recorded in 4.16 % of cases. After 12 months, a significant reduction or complete resolution of GC-associated complications was observed in most patients: only 7 cases (9.72 %) of pathology associated with GC therapy were recorded.Conclusions. In patients with acute severe myocarditis with a history of coronavirus disease, glucocorticoid therapy demonstrated greater efficacy in improving the structural and functional state of the heart after 6 months of follow-up compared to patients without a history of COVID-19. The use of glucocorticoids in patients with severe myocarditis was associated with the development of complications in more than a half of patients within the first 6 months of follow-up, while after 12 months, there was a significant reduction in their frequency or their complete regression. During the 12-month observation period, none of the patients developed diseases or pathological conditions associated with glucocorticoid use that required inpatient treatment.

Long-Term Complications in Patient-Specific Plates for Maxillary Reconstruction.

Virtual surgical planning (VSP) allows for optimal reconstruction of maxillary defects with fibula free flaps. Current data are limited regarding long-term complications of patient-specific plates (PSPs) in this setting. Our objective was to determine long-term complications of PSPs in maxillary reconstruction using fibula free flaps. A retrospective chart review was performed on patients undergoing maxillary reconstruction with a fibula free flap and PSP between January 2010 to July 2022. The primary outcomes were plate-related complications, which were defined as plate exposure, fracture, removal or evidence of loose screws. Secondary outcomes were wound infection, nonunion, or flap failure. A total of 39 patients underwent fibular reconstruction of maxillary defects using PSP. The average age was 56 years, with 56% of patients being female. There were 14 (35.8%) patients with plate-related complications, 10 (25.6%) underwent plate removal, 12 (30.8%) developed exposed hardware, 2 (5.1%) had loose screws, and none had a plate fracture. The average time to plate removal was 2.76 ± 1.94 years. With regard to age, sex, tobacco or alcohol use, diabetes, hypothyroidism, preoperative radiation therapy, number of fibula segments, type of cancer, postoperative radiation therapy, or whether the patient underwent orodental rehabilitation, there were no significant differences between patients who did and did not experience plate complications. VSP allows for patient-specific reconstruction of maxillary defects with a fibula free flap that remains stable in the majority of patients. In the long term, up to 25% of patients may require plate removal, but the reconstruction remains stable. Level 4.

Magnetic Resonance Imaging in the Assessment of the Risk of Sudden Death in Cardiac Sarcoidosis: What Is Extensive or Significant Late Gadolinium Enhancement?

Cardiac sarcoidosis involves a significant but difficult-to-define risk of sudden cardiac death (SCD). Current guidelines recommend consideration of an implantable cardioverter defibrillator for patients with extensive or significant myocardial late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging. However, extensive/significant LGE is not defined. A nationwide cardiac sarcoidosis registry was screened for patients entered before 2020 with cardiac magnetic resonance imaging done before or <3 months after diagnosis. Available studies were re-analyzed for LGE mass as a percentage of left ventricular (LV) mass and the number of LGE-positive LV segments in a 17-segment model. The occurrence of fatal or aborted SCD and ventricular tachycardia (VT) prompting therapy was recorded until the end of 2020 and subjected to cumulative incidence analyses, including competing events (LV assist device implantations, heart transplantations, and fatalities other than SCD). The predictors of SCD/VT were assessed using Fine and Gray modeling and time-dependent receiver operating characteristic analysis. Altogether, 305 patients (66% women, median age 51) with clinically manifest, definite (45%) or probable cardiac sarcoidosis (55%) were analyzed. On follow-up (median, 4.0 years), 21 SCDs, 60 VTs, and 14 competing events were noted. Both LGE mass and the number of LGE segments predicted the composite of SCD/VT (P<0.001), with receiver operating characteristic analyses identifying LGE mass ≥9.9% and ≥6 LGE segments as discriminative thresholds. At presentation, 70 patients were free of class I and class IIa implantable cardioverter defibrillator indications unrelated to LGE. Their 5-year rate of SCD/VT was 6.3% (0.0-14.8%) with LGE mass <9.9% versus 21.5% (6.5-36.6%) with higher LGE mass, and 6.9% (0.0-16.3%) with <6 LGE segments versus 20.5% (5.9-35.2%) with ≥6 segments. In cardiac sarcoidosis, myocardial LGE making up ≥9.9% of LV mass or affecting ≥6 LV segments may suggest prognostically significant LV involvement and a high risk of SCD. However, prospective validation of the thresholds is needed.

ОТВЕТНЫЕ РЕАКЦИИ HYALELLA AZTECA НА ДЕЙСТВИЕ ЛАНТАНА В УСЛОВИЯХ ХРОНИЧЕСКОГО ЭКСПЕРИМЕНТА

The responses of the laboratory culture Hyalella azteca to the effect of lanthanum sulfate solutions in the concentration range of 0.16–160 μmol/l under conditions of a chronic trial were studied. It was shown that the mortality of H. azteca increased with an enhance in the concentration of La3+ in the solution. A consistent increase in the concentration of La3+ led to a natural raise in food consumption. The most informative test function in assessing the toxicity of La3+ is the length and weight of H. azteca, while the length and number of antennal segments are not informative.

Step-Wise Parameter Adaptive FMD Incorporating Clustering Algorithm in Rolling Bearing Compound Fault Diagnosis

Ideally, the vibration signal of a rolling bearing should be symmetrical. However, in practical operation, the vibration signals in both time and frequency domains often exhibit asymmetry due to factors such as load, speed, and wear. The relatively weak composite fault characteristics are easily masked. Although the Feature Modal Decomposition (FMD) method is outstanding in diagnosing composite faults in bearings, its effectiveness is easily constrained by parameter selection. To address this, this paper proposes a stepwise parameter adaptive FMD method combined with a clustering algorithm, specifically designed for diagnosing composite faults in rolling bearings. Firstly, this study employs the Density Peak Clustering algorithm to determine the number of modes n in the composite fault vibration signal. Subsequently, considering the signal spectral energy and modal characteristics, a new composite fault index is formulated, namely, the adaptive weighted frequency domain kurtosis-to-information entropy ratio, as the fitness function. The Whale Optimization Algorithm determines the filter length L and the number of segments K, thereby achieving step-wise signal decomposition. Through in-depth analysis of signal symmetry and asymmetry, simulation and experimental verification confirm the effectiveness of this method. Compared with four other index-optimized FMD methods and traditional techniques, this method significantly reduces the influence of parameters on FMD, is capable of separating the characteristic frequencies related to composite faults, and performs excellently in the diagnosis of composite faults in rolling bearings.

Evaluation of dendrite morphology in Wistar and genetic absence epileptic rats.

Genetic Absence Epilepsy Rat from Strasbourg (GAERS), a rodent model genetically predisposed to absence epilepsy, serves as an experimental tool to elucidate the neuronal mechanisms underlying human absence epilepsy. This study aimed to investigate the morphological features of dendrites and dendritic spines of pyramidal neurons in somatosensory cortex and hippocampus of Wistar and GAERS rats. Adult male GAERS (n = 5) and control Wistar (n = 5) rats were sacrificed by transcardial perfusion and brains were removed. Brain tissues were processed by Golgi impregnation method using FD Rapid GolgiStain Kit. Coronal sections were obtained with a cryostat. Pyramidal neurons in layers V-VI of the somatosensory cortex and the CA1 region of the hippocampus were examined using a light microscope and Neurolucida 360 software. Dendrite nodes, dendrite segments (dendritic branching), dendrite terminations, total dendrite length, dendritic spine density, and dendritic spine types were analyzed. Compared to Wistar, GAERS exhibited significantly higher numbers of nodes (p = 0.0053, p = 0.0047), segments (p = 0.0036, p = 0.0036), and terminations (p = 0.0033, p = 0.0029) in the dendrites of the somatosensory cortex and the hippocampus, respectively. Furthermore, the total dendrite length (µm) (p = 0.0002, p = 0.0007) and the density of dendritic spines (1/µm) (p = 0.0168, p = 0.0120) were significantly high in GAERS compared to Wistar. When dendritic spine types were evaluated separately, stubby-type dendritic spines in the hippocampus were higher in GAERS compared to Wistar (p = 0.0045). Intense synaptic connections in the somatosensory cortex and the hippocampus of genetic absence epileptic rats led to morphological alterations in the dendrites and the dendritic spines of pyramidal neurons in these regions, potentially contributing to the pathophysiology of absence seizures.

Pengaruh Jumlah Segmen, Total Monitor Unit, Volume Tumor dan Jumlah Arah Penyinaran terhadap Delivery Time pada Intensity Modulated Radiation Therapy (IMRT) Kanker Otak: Studi Observasi di RS Ken Saras

Background: Intensity Modulated Radiation Therapy allows for more precise treatment but has challenges, namely, long delivery times. Delivery time in IMRT is influenced by parameters such as the number of segments, total monitor units, tumor volume, and the number of beam angle; in the radiotherapy installation of Ken Saras Hospital in making IMRT planning focuses on planning quality. IMRT planning parameters that affect delivery time have never been studied before. The purpose of this study is to determine the effect of the number of segments, total monitor units, tumor volume, and number of beam angle on IMRT delivery time in brain cancer. Methods: this study is analytical observational, sample patient data from January 2022 to December 2023, data samples totaled 30 brain cancer patients, data analysis using statistics tests. Results: The results of the study show that the independent variables affect the dependent variable in brain cancer. First significant parameter is the number of beam angle with coefficients value of (+) 11.403, which means that the addition of 1 number of beam angle will increase the delivery time value by 11.403. Second parameter is the number of segments with coefficients value of (+) 4.406, this means that the addition of 1 number of segments will increase the delivery time value by 4.406. Third parameter is tumour volume with coefficients value of 0.121. Conclusions: The results showed that the parameters significantly affect the delivery time of IMRT in brain cancer are number of segments, tumor volume and number of beam angle.

Magnetic Resonance Imaging Liver Segmentation Protocol Enables More Consistent and Robust Annotations, Paving the Way for Advanced Computer-Assisted Analysis

Background/Objectives: Recent advancements in artificial intelligence (AI) have spurred interest in developing computer-assisted analysis for imaging examinations. However, the lack of high-quality datasets remains a significant bottleneck. Labeling instructions are critical for improving dataset quality but are often lacking. This study aimed to establish a liver MRI segmentation protocol and assess its impact on annotation quality and inter-reader agreement. Methods: This retrospective study included 20 patients with chronic liver disease. Manual liver segmentations were performed by a radiologist in training and a radiology technician on T2-weighted imaging (wi) and T1wi at the portal venous phase. Based on the inter-reader discrepancies identified after the first segmentation round, a segmentation protocol was established, guiding the second round of segmentation, resulting in a total of 160 segmentations. The Dice Similarity Coefficient (DSC) assessed inter-reader agreement pre- and post-protocol, with a Wilcoxon signed-rank test for per-volume analysis and an Aligned-Rank Transform (ART) for repeated measures analyses of variance (ANOVA) for per-slice analysis. Slice selection at extreme cranial or caudal liver positions was evaluated using the McNemar test. Results: The per-volume DSC significantly increased after protocol implementation for both T2wi (p &lt; 0.001) and T1wi (p = 0.03). Per-slice DSC also improved significantly for both T2wi and T1wi (p &lt; 0.001). The protocol reduced the number of liver segmentations with a non-annotated slice on T1wi (p = 0.04), but the change was not significant on T2wi (p = 0.16). Conclusions: Establishing a liver MRI segmentation protocol improves annotation robustness and reproducibility, paving the way for advanced computer-assisted analysis. Moreover, segmentation protocols could be extended to other organs and lesions and incorporated into guidelines, thereby expanding the potential applications of AI in daily clinical practice.

Robust and Fast Point Cloud Registration for Robot Localization Based on DBSCAN Clustering and Adaptive Segmentation.

This paper proposes a registration approach rooted in point cloud clustering and segmentation, named Clustering and Segmentation Normal Distribution Transform (CSNDT), with the aim of improving the scope and efficiency of point cloud registration. Traditional Normal Distribution Transform (NDT) algorithms face challenges during their initialization phase, leading to the loss of local feature information and erroneous mapping. To address these limitations, this paper proposes a method of adaptive cell partitioning. Firstly, a judgment mechanism is incorporated into the DBSCAN algorithm. This mechanism is based on the standard deviation and correlation coefficient of point cloud clusters. It improves the algorithm's adaptive clustering capabilities. Secondly, the point cloud is partitioned into straight-line point cloud clusters, with each cluster generating adaptive grid cells. These adaptive cells extend the range of point cloud registration. This boosts the algorithm's robustness and provides an initial value for subsequent optimization. Lastly, cell segmentation is performed, where the number of segments is determined by the lengths of the adaptively generated cells, thereby improving registration accuracy. The proposed CSNDT algorithm demonstrates superior robustness, precision, and matching efficiency compared to classical point cloud registration methods such as the Iterative Closest Point (ICP) algorithm and the NDT algorithm.

PRO-QOL after gross total resection of spinal ependymoma: a retrospective study based on 3-year follow-up observations in a single center.

Although many studies have reported clinical outcomes of spinal ependymoma (SE) patients after gross total resection (GTR), the data about the patient reported outcomes of the quality of life (PRO-QOL) was limited. This study investigated the recovery process of PRO-QOL and explored the possibility of predicting the recovery of postoperative QOL by preoperative clinical indicators. A retrospective analysis was performed in 71 SE patients who underwent GTR in our center from 2016 to 2022. The PRO-QOL data were collected by questionnaire, which included the EuroQol 5-Dimensions 5-Levels (EQ-5D-5L) scale and visual pain analogue score (VAS). Factors affecting postoperative PRO-QOL deterioration was assessed by the univariate and multivariate analyses. 71 SE patients who undergone GTR were included and followed by mean of 36 months (range 27-58). The overall PRO-QOL recovered to a stable level 6 months after surgery, but the ability of self-care, as one of the dimensions of QOL, continued to improve up to one year after surgery. 21 (29.6%) patients reported that their QOL became worse at one year after surgery. The result of statistical analysis suggested that preoperative Modified McCormick Scale (MMS), the number of segments involved by the tumor and preoperative VAS score were identified as main preoperative variables for predicting QOL deterioration. From the perspective of PRO-QOL, neurological rehabilitation should be continued for at least 6-12 months after GTR to the SE patients. For the preoperative patients with severe neurological damage, long-level intraspinal tumor and low VAS score, more cautious surgical considerations, more perioperative attention and earlier neurological intervention are necessary.