Failure Of Segmentation Research Articles

Radiation Dose to Ipsilateral Subventricular Zone as a Prognostic Factor in Malignant Glioma Patients

ranging from 18-30 Gy in 1-6 fractions (54% were 24 Gy x 1). All patients were evaluated and managed by a multidisciplinary spine team including a radiation oncologist, neurosurgeon, and interventional radiologist. Twentyseven percent of lesions were surgically resected prior to SBRT and 48% of lesions had radiographic epidural disease at time of SBRT. All sites of progression within the spinal axis were mapped according to number of vertebral levels away from the treated lesion. Kaplan-Meier method was used to capture actuarial rates, and R-squared statistics were used to assess correlation. Results: The median follow-up for the cohort was 14.4 months, with 82% of patients followed until death. At the time of last follow-up, 47% (nZ56) of patients had not progressed at any site in the spinal axis. Of the remaining 53% (nZ64), only 23% (nZ15) progressed at a single vertebral level, with 59% (nZ38) progressing at 3 sites within the spine simultaneously. The 1-year actuarial local failure-free survival (LFFS), adjacent segment failure-free survival (ASFFS), and distant segment failure-free survival rates were 87%, 85%, and 66%, respectively. However, 75% of local failures and 90% of adjacent segment failures occurred in conjunction with distant spine failures. The 1-year actuarial rate for isolated LFFS and isolated ASFFS were 96% and 98%, respectively. The patterns of failure by distance from the treated lesion were 8.4% crude failure at the index lesion and 10.8%, 11.6%, 10.3%, and 6.8% for lesions 1, 2, 3, and 4 segments away. Linear regression analysis revealed a relationship of decreasing risk of failure with increasing distance from the treated index lesion (R Z 0.87), and 52% occurred 5 segments away. Conclusion: We report the first detailed spinal axis patterns of failure analysis for patients undergoing SBRT for metastatic osseous spine disease. We demonstrate that local control is excellent, and importantly, isolated local and adjacent segment failures are 5 vertebral levels away from the index lesion. Thus, total spine imaging in close interval is requisite for surveillance post-treatment. Author Disclosure: J.E. Leeman: None. M. Bilsky: None. I. Laufer: None. M.R. Folkert: None. N.K. Taunk: None. J.R. Osborne: None. J. Zatcky: None. K.M. Alektiar: None. Y. Yamada: Consultant; Varian Medical. D.E. Spratt: None.

Dosimetric Evaluations of Different Accelerator Based Treatment Modalities for Curative Intent Stereotactic Body Radiation Therapy of Isolated Thoracic Spinal Metastases

ranging from 18-30 Gy in 1-6 fractions (54% were 24 Gy x 1). All patients were evaluated and managed by a multidisciplinary spine team including a radiation oncologist, neurosurgeon, and interventional radiologist. Twentyseven percent of lesions were surgically resected prior to SBRT and 48% of lesions had radiographic epidural disease at time of SBRT. All sites of progression within the spinal axis were mapped according to number of vertebral levels away from the treated lesion. Kaplan-Meier method was used to capture actuarial rates, and R-squared statistics were used to assess correlation. Results: The median follow-up for the cohort was 14.4 months, with 82% of patients followed until death. At the time of last follow-up, 47% (nZ56) of patients had not progressed at any site in the spinal axis. Of the remaining 53% (nZ64), only 23% (nZ15) progressed at a single vertebral level, with 59% (nZ38) progressing at 3 sites within the spine simultaneously. The 1-year actuarial local failure-free survival (LFFS), adjacent segment failure-free survival (ASFFS), and distant segment failure-free survival rates were 87%, 85%, and 66%, respectively. However, 75% of local failures and 90% of adjacent segment failures occurred in conjunction with distant spine failures. The 1-year actuarial rate for isolated LFFS and isolated ASFFS were 96% and 98%, respectively. The patterns of failure by distance from the treated lesion were 8.4% crude failure at the index lesion and 10.8%, 11.6%, 10.3%, and 6.8% for lesions 1, 2, 3, and 4 segments away. Linear regression analysis revealed a relationship of decreasing risk of failure with increasing distance from the treated index lesion (R Z 0.87), and 52% occurred 5 segments away. Conclusion: We report the first detailed spinal axis patterns of failure analysis for patients undergoing SBRT for metastatic osseous spine disease. We demonstrate that local control is excellent, and importantly, isolated local and adjacent segment failures are 5 vertebral levels away from the index lesion. Thus, total spine imaging in close interval is requisite for surveillance post-treatment. Author Disclosure: J.E. Leeman: None. M. Bilsky: None. I. Laufer: None. M.R. Folkert: None. N.K. Taunk: None. J.R. Osborne: None. J. Zatcky: None. K.M. Alektiar: None. Y. Yamada: Consultant; Varian Medical. D.E. Spratt: None.

The relative survival of composite free flaps in head and neck reconstruction

Various composite free flaps are available for reconstruction of bony head and neck defects. The aim of this study was to compare the relative success of four different bony free flaps. One hundred and seventy-three microvascular composite free flap reconstructions for bony defects of the head and neck region, performed over the period April 2008 to April 2015, were reviewed retrospectively. The type of free flap, indication for free flap reconstruction, age at harvesting of the free flap, use of pre- or postoperative radiotherapy, and free flap failure were examined. For the 173 reconstructions performed, 84 fibula free flaps, 43 iliac crest free flaps, 32 scapula free flaps, and 14 osteocutaneous radial forearm free flaps were harvested. The mean age at time of harvesting was 40.7 years for the iliac crest, 57.3 years for the fibula, 64.3 years for the scapula, and 73.9 years for the osteocutaneous radial forearm free flap. No complete free flap failure was documented, nor was there any failure of bony segments. Three fibula flap skin paddles did not survive. No returns to theatre for salvage were required. This study showed no difference in the survival rates of these four types of composite free flap.

Study of TBM cutterhead fatigue damage mechanisms based on a segmented comprehensive failure criterion

The cutterhead endures strong, multi-point distributed impact loads when the full face rock tunnel boring machine (TBM) tunnels, which leads to intense vibration and fatigue fracture. Accordingly the structure should meet the requirement of service life considering the fracture failure at weak locations. Hence, cutterhead damage mechanism is crucial to predict and analyze residual life of a operational cutterhead under impact loads. This paper combines with the characteristics of cutterhead life, Paris model and damage cumulative theory, proposes a new failure criterion for the long thick plate in complex stress states, and establishes a segmented crack propagation life prediction model, based on the existing multi-degree-of-freedom coupling dynamic TBM cutterhead model and fatigue crack propagation prediction method for large and complex structures. Meanwhile, a physical fatigue damage test of cutterhead specimens is carried out to validate the theoretical model. Then a TBM cutterhead in a water tunnel project is taken as an example, to calculate the fatigue crack propagation and analyze how different parameters affect fatigue life. The results of the analyses reveal that with fatigue crack propagation, life of actual cutterhead is 36.5km, which gives a meaningful reference for cutterhead design. In addition, the cutterhead life decreases nearly 45.2% with the initial crack depth increasing from 0.5mm to 2mm, and it is inferred that the value of initial crack depth should be controlled below 1.6mm, to ensure the service life. On the other side, the larger the crack shape ratio (a/c), the longer the fatigue life, and the cutterhead life with a round crack (a/c=1) is about 3 times with a narrow crack (a/c=0.1). Furthermore, the crack growth rate parameter m has greater influence on cutterhead life than parameter C, with C increasing 10%, the life decreases about 9%; however, the life decreases nearly 13% when m increases 1%. Then, the critical threshold values of cutterhead material parameters to meet life requirement are obtained. From the results of fatigue damage test, it can be showed that the specimens fracture quickly when the crack depth exceeds 50% of the panel thickness, and the crack shape ratio gradually increases with the loading cycles, which is consistent with the theoretical assumption, as well as the influence rules of parameters.

The relationship between segmentation failure and spermatozoa motility characteristics

Dynamics of sperm motility (sperm velocity, percentage of motility and flagellar beat frequency) and monthly variations of semen characteristics (semen volume and osmolality and sperm concentration and motility) were studied. These criteria were used in the embryology laboratory and reproductive biology in the city of Lattakia, Syria, This study showed that sperm velocity, percentage of motility and beat frequency significantly and rapidly decreased after the activation of sperm motility. To study the dynamics of sperm motility parameters, twenty permeating males were randomly selected and electronically tagged to study the variations of semen characteristics. Specially we focused on the relationship between segmentation failure in cases treated with In Vitro Fertilization (IVF) to define the characteristics using the Computer Assisted Sperm Analysis (CASA). This study compares the reference group (normal) and a group of individuals treated with IVF, who have failed the treatment where segmentation did not occur. The role of the spermatozoon in fertilization expresses itself especially through the motility criterion. Studying the motility characteristics using CASA method seems interesting in clarifying the relationship between some of the motility characteristics and the ability to fertilize in order to determine the notification in cases of IVF. This study based on the acquired information of 85 normal voluntaries as references cases. And 45 patients with segmentation failure in the Embryology-lab of Al-Andalus University for medical Sciences between 2012- 2013. The results were clear, that significant relationship and correlation between segmentation failure and motility of the sperms.

The ideology of the ethical consumption gap

The growth of contemporary capitalism is producing a broad sweep of environmental and social ills, such as environmental degradation, exploitative labor conditions, social and economic inequity, and mental and physical illness. A growing awareness of these significant consequences by an “ethical” consumer segment has catalyzed a field of research dedicated to investigating ethical consumerism. Of particular academic and practitioner focus is the general failure of this ethical consumer segment to “walk their talk”—the ethical consumption attitude–behavior ‘gap’. In this article, we draw on Althusser and Žižek to critically analyze the ideological functioning of the ethical consumption gap. We argue that this focus inadvertently promotes erroneous notions of consumer sovereignty and responsibilization. We conclude with a call to reimagine the gap as a construct that paradoxically preserves—rather than undermines—dominant and destructive consumerist capitalism. We redirect research toward the underlying capitalist structures that predicate and benefit from the gap.

Preoperative (3-dimensional) computed tomography lung reconstruction before anatomic segmentectomy or lobectomy for stage I non–small cell lung cancer

ObjectivesAccurate cancer localization and negative resection margins are necessary for successful segmentectomy. In this study, we evaluate a newly developed software package that permits automated segmentation of the pulmonary parenchyma, allowing 3-dimensional assessment of tumor size, location, and estimates of surgical margins. MethodsA pilot study using a newly developed 3-dimensional computed tomography analytic software package was performed to retrospectively evaluate preoperative computed tomography images of patients who underwent segmentectomy (n = 36) or lobectomy (n = 15) for stage 1 non–small cell lung cancer. The software accomplishes an automated reconstruction of anatomic pulmonary segments of the lung based on bronchial arborization. Estimates of anticipated surgical margins and pulmonary segmental volume were made on the basis of 3-dimensional reconstruction. ResultsAutosegmentation was achieved in 72.7% (32/44) of preoperative computed tomography images with slice thicknesses of 3 mm or less. Reasons for segmentation failure included local severe emphysema or pneumonitis, and lower computed tomography resolution. Tumor segmental localization was achieved in all autosegmented studies. The 3-dimensional computed tomography analysis provided a positive predictive value of 87% in predicting a marginal clearance greater than 1 cm and a 75% positive predictive value in predicting a margin to tumor diameter ratio greater than 1 in relation to the surgical pathology assessment. ConclusionsThis preoperative 3-dimensional computed tomography analysis of segmental anatomy can confirm the tumor location within an anatomic segment and aid in predicting surgical margins. This 3-dimensional computed tomography information may assist in the preoperative assessment regarding the suitability of segmentectomy for peripheral lung cancers.

Region-based feature extraction from non-cooperative iris images using CDF 9/7 filter bank

In this paper, the authors have investigated the iris feature extraction technique using Cohen–Daubechies–Feauveau 9/7 (CDF 9/7) filter bank. Most of the iris recognition systems have been found to give near perfect performance in constraint environment. Unfortunately, the accuracy falls drastically when the constraints are relaxed during image acquisition process. These include dilation of pupil, occlusion due to eyelids and eye lashes, and most importantly non-orthogonal view of iris. These factors result in reduced accuracy of the overall system. In this work, a technique has been proposed to deal with segmentation failure and occlusion. The experimental studies deal with the superiority of CDF 9/7 filter bank over the frequency-based techniques.

Chain Segment Analysis

The work is aimed at a detailed analysis of impaired chain segments manufactured by welding and determining the cause of chain segment failure. The main interest was focused on the base material structure, the quality of weld joint, the heat treatment of the weldment, and the overall condition of the component after operating workload. The chain segments were investigated in terms of the microstructure by means of the light microscope, scanning electron microscope equipped with an energy dispersive microanalyser, and hardness measurement.

Region based feature extraction from non-cooperative iris images using triplet half-band filter bank

Abstract In this paper, we have proposed energy based features using a multi-resolution analysis (MRA) on iris template. The MRA is based on our suggested triplet half-band filter bank (THFB). The THFB derivation process is discussed in detail. The iris template is divided into six equispaced sub-templates and two level decomposition has been made to each sub-template using THFB except second one. The reason for discarding the second template is due to the fact that it mostly contains the noise due to eyelids, eyelashes, and occlusion due to segmentation failure. Subsequently, energy features are derived from the decomposed coefficients of each sub-template. The proposed feature has been experimented on standard databases like CASIAv3, UBIRISv1, and IITD and mostly on iris images which encounter a segmentation failure. Comparative analysis has been done with existing features based on Gabor transform, Fourier transform, and CDF 9/7 filter bank. The proposed scheme shows superior performance with respect to FAR, GAR and AUC.

Early clinical results with cortically based pedicle screw trajectory for fusion of the degenerative lumbar spine

This study reviews the outcomes and revision rates of degenerative lumbar fusion surgery using cortical trajectory pedicle screws in lieu of traditional pedicle screw instrumentation. Pedicle screw fixation can be a challenge in patients with low bone mineral density. Wide posterior approaches to the lumbar spine exposing lateral to the facet joints and onto transverse processes causes an additional degree of muscular damage and blood loss not present with a simple laminectomy. A cortical bone trajectory pedicle screw has been proposed as an alternative to prevent screw pullout and decrease the morbidity associated with the wide posterior approach to the spine. We present a series of eight consecutive patients using a cortical bone trajectory instead of traditional pedicle screw fixation for degenerative conditions of the lumbar spine. A retrospective review of our institutional registry data identified eight patients who had cortical screws placed with the assistance of O-arm Stealth navigation (Medtronic Sofamor Danek, Memphis, TN, USA) from 2010–2013. We analyzed the need for revision, the maintenance of reduction and the incidence of screw pullout or breakage. Our review demonstrated that two of eight patients were revised at an average of 12months. The reasons for these revisions were pseudarthrosis and caudal adjacent segment failure. All patients who were revised had frank screw loosening. We present early clinical results of a new technique that has been shown to have a better fixation profile in laboratory testing. Our less than favorable early clinical results should be interpreted with caution and highlight important technical issues which should be considered.

Vertebral, rib, and intraspinal anomalies in congenital scoliosis: a study on 202 Caucasians.

To investigate vertebral, rib and intraspinal anomalies in patients with congenital scoliosis and their association with each other Clinical data and preoperative imaging studies of 202 Caucasians with congenital scoliosis operated on at an educational hospital within 6 years were reviewed for vertebral, rib, and intraspinal anomalies. Rib and intraspinal anomalies were present in 57.4 and 21.8 % of patients, respectively. Most vertebral anomalies were located in the middle-lower thorax. Being the most common vertebral defect (53.5 %), failure of segmentation was significantly more common in males, whereas mixed defects were more frequent in females. Formation and mixed defects were associated with rib changes. Vertebral anomalies were more extensive in males than in females. The presence of multiple hemivertebrae was associated with rib deformity and intraspinal anomaly. Location of the vertebral anomalies varied with gender and rib involvement. Majority of rib changes were of simple type (70.7 %), significantly more common in males. Conversely, females had significantly more fused and bifid ribs. Two most common intraspinal anomalies were diastematomyelia (36.4 %) and syringomyelia (18.2 %). Intraspinal anomalies were located most frequently in the upper and lower thoracic regions. Syringomyelia and low conus were associated with female gender, and patients with rib changes suffered from intraspinal anomalies more frequently. No significant association was found between vertebral and intraspinal anomalies. The incidences of rib and intraspinal anomalies were 57.4 and 21.8 % in surgical Caucasians with congenital scoliosis, respectively. Unlike vertebral and intraspinal anomalies, rib and intraspinal anomalies were significantly associated. Male gender and intraspinal anomaly were associated with some previously suggested risk factors of curve progression.

Environmental aspects of congenital scoliosis.

Growing evidence has proved that many aspects of our lifestyle and the environment contribute to the development of congenital disease. Congenital spinal deformities are due to anomalous development of the vertebrae including failure of formation and segmentation during embryogenesis. The causes of congenital scoliosis have not been fully identified. A variety of factors are implicated in the development of vertebral abnormalities. Previous studies have demonstrated that both genetics and environmental factors are implicated in the development of vertebral abnormalities. However, no specific cause for congenital scoliosis has been identified. In our review, we focus on the environmental factors for the development of congenital scoliosis. Various maternal exposures during pregnancy including hypoxia, alcohol use, vitamin deficiency, valproic acid, boric acid, and hyperthermia have been observed to be associated with the occurrence of congenital scoliosis. This review describes the major environmental contributors of congenital scoliosis with an emphasis on treatment aspects associated with environmental disposition in congenital scoliosis.

English

The basilar process of occipital bone is formed by fusion of the first three primitive vertebrae (or occipitoblasts), the most caudal of which is so-called occipital vertebra or pro-atlas. The failure of distal occipitoblasts to fuse with others gives rise to abnormal bone formations on the external surface of skull around foramen magnum, phenomenon called as manifestation of occipital vertebra. Bone anomalies related to failure of segmentation of the most caudal occipital sclerotomes are rare, but have been identified. The anomaly leads to abnormal bone formation in the region of anterior rim of foramen magnum, either in the midline and or laterally. The anomaly has been occasionally referred to as third condyle, remanants of occipital vertebra, un-formed bone masses on the anterior rim of foramen magnum and prebasi-occipital arch in combination with an odontoid bone. The basiocciput of 100 Indian adult human skulls were examined for the presence of precondylar tubercles, which are single or paired osseous formations anterior to the occipital condyles and foramen magnum. Out of these 100 skulls, one skull displayed unilateral tubercle and the other bilateral tubercles.

Characterization of single amino acid substitutions in the β2 integrin subunit of patients with leukocyte adhesion deficiency (LAD)-1.

Leukocyte adhesion deficiency 1 (LAD-1) is caused by defects in the β2 integrin subunit. We studied 18 missense mutations, 14 of which fail to support the surface expression of the β2 integrins. Integrins with the β2-G150D mutation fail to bind ligands, possibly due to the failure of the α1 segment of the βI domain to assume an α-helical structure. Integrins with the β2-G716A mutation are not maintained in their resting states, and the patient has the severe phenotype of LAD-1. The β2-S453N and β2-P648L mutants support the expression of integrins and adhesion functions. They should be re-classified as polymorphic variants.

Analyse d’un modèle théorique de la conception dimensionnelle du narcissisme pathologique : incidences probables sur le leadership organisationnel

The purpose of this case study is to examine the appropriateness of the dimensional model of pathological narcissism developed by Roche, Pincus, Lukowitsky, Ménard and Conroy (2013). The exploration was essentially focused on decompensatory segment (failure of maladaptive self-enhancement strategies) of this model. By using a longitudinal research design, the results, although fragmentary, isolated a positive relationship between the two dimensions – grandiosity and vulnerability – of pathological narcissism. This positive relationship exists both in compensatory segment (use of maladaptive self-enhancement strategies) and in decompensatory segment of the model.

Optical coherence tomography in papilledema: what am I missing?

Grading of papilledema severity is subjective and based on monocular fundus features of the optic nerve. Interobserver agreement on grading the severity of papilledema is poor among expert observers, even using well-defined criteria such as the Frisen scale, which is a non-continuous ordinal scale of grading. Furthermore, non-expert clinicians often find it difficult to properly view and interpret features of the optic nerve using ophthalmoscopy, which can lead to failure to diagnose papilledema in non-ophthalmologic care settings. This may delay treatment, which can result in vision loss. Distinguishing papilledema from pseudopapilledema can also be difficult when surface drusen are not easily identified. Once papilledema is diagnosed, it is often difficult to determine whether a reduction in optic nerve edema is due solely to improvement in the status of the nerve or whether this represents concomitant loss of axons and viable retinal ganglion cells, leading to a poor visual outcome. Timely advancement of treatment would occur if loss of neurons could be diagnosed at an earlier stage of evaluation while optic disc edema is still present. This review will critically assess the role of optical coherence tomography (OCT) in solving these problems by providing an advanced imaging approach for diagnosis of papilledema and evaluating its severity on a continuous scale and evaluating the causes of visual loss in the setting of a swollen nerve. The published literature (PubMed) was reviewed from 2000 to 2014 on the use of OCT for diagnosing papilledema, differentiating it from pseudopapilledema, providing a continuous scale of its severity and in evaluating causes of visual loss. Recent evidence shows that OCT analysis of the retinal nerve fiber layer and retinal ganglion cell layer in papilledema can be associated with misleading artifacts due to layer segmentation failures. Newer 3D algorithms using neighboring locations help to overcome these problems. Disc volume appears to be a promising continuous measure of papilledema that is robust and has less associated artifacts. Buried optic disc drusen can be identified using enhanced depth OCT imaging, but recent studies have shown poor ability to differentiate papilledema from pseudopapilledema using OCT when the degree of disc evaluation is similar. Analysis of the retinal ganglion cell layer shows promise of early detection of vision loss due to neuronal injury. Subretinal fluid is easily identified with OCT and can help to identify a potentially reversible component of vision loss. Newer OCT imaging methods will allow the definition of capillaries and flow within them in and around the optic nerve head. Currently, the most useful OCT derived features relevant to papilledema are disc volume, subretinal fluid, buried disc drusen, and thickness of the retinal ganglion cell layer.

Pengaruh Pencahayaan terhadap Kinerja Segmentasi

Light intensity may affect the image quality of an object that can cause barriers in doing preprocessing to improve the image quality of a digital image. Furthermore, this would also be an impact on subsequent processes, such as sorting images according to the needs. Light intensity influences the reflection of light which translates into an image. This gives an impact on successful segmentation process. Examples of the success and failure of segmentation are presented in this paper.

How Healthy Discs Herniate

Microstructural investigation of compression-induced disruption of the flexed lumbar disc. To provide a microstructural analysis of the mechanisms of annular wall failure in healthy discs subjected to flexion and an elevated rate of compression. At the level of the motion segment failure of the disc in compression has been extensively studied. However, at the microstructural level the exact mechanisms of disc failure are still poorly understood, especially in relation to loading posture and rate. Seventy-two healthy mature ovine lumbar motion segments were compressed to failure in either a neutral posture or in high physiological flexion (10°) at a displacement rate of either 2 mm/min (low) or 40 mm/min (high). Testing at the high rate was terminated at stages ranging from initial wall tearing through to facet fracture so as to capture the evolution of failure up to full herniation. The damaged discs were then analyzed microstructurally. Approximately, 50% of the motion segments compressed in flexion at the high rate experienced annulus or annulus-endplate junction failure, the remainder failed via endplate fracture with no detectable wall damage. The average load to induce disc failure in flexion was 18% lower (P < 0.05) than that required to induce endplate fracture. Microstructural analysis indicated that wall rupture occurred first in the posterior mid-then-outer annulus. Disc wall failure in healthy motion segments requires both flexion and an elevated rate of compression. Damage is initiated in the mid-then-outer annular fibers, this a likely consequence of the higher strain burden in these same fibers arising from endplate curvature. Given the similarity in geometry between ovine and human endplates, it is proposed that comparable mechanisms of damage initiation and herniation occur in human lumbar discs. N/A.

Concurrent Klippel-Feil Anomaly, Tethering and Dermoid Cyst Misinterpreted as Pott disease: A Case Report

Klippel-Feil syndrome (KFS) is characterized by the failure in segmentation of two or more vertebrae due to an abnormal division of the mesodermal somites and has been reported to be associated with cardiac and central nervous system anomalies. We report a rare occurrence of concurrent Klippel-Feil anomaly, tethering and dermoid cyst of dorsal spine masquerading Potts’ disease in an eighteen years old female. In rare instances the KFS can be associated with intracranial or spinal tumors, most frequently dermoid or epidermoid cysts. Key Words Congenital spinal malformation, Klippel-Feil syndrome, dermal sinus, dermoid cysts