54 research outputs found
Les stratégies de recherche d’aide des femmes victimes de violence conjugale : le cas des femmes référées aux CLSC par les policiers
Get PDFThis article deals with formal and informal resources used by women victims of conjugal violence in their search for help. It explores the type of resources used and their relationship with a number of factors such as the socio-economic characteristics of the women and, the nature and duration of the violence which they have suffered. Prior to reporting on the results of a specific case of formal resources utilization, this article presents a review of the literature on the process of seeking help, then it focuses on the major role played by the social support network. Also, it reviews the major studies dealing with the strategies used by women victims of conjugal violence in obtaining help. Finally, the article reports on the main results of a study conducted in the context of a pilot project to bring help to victims of conjugal violence by the police and the Local Community Services Centers (CLSC) of the Montreal Urban Community. This pilot project started in 1990 has since been extended to the entire territory covered by the Montreal Urban Community. The results of this study show that the majority of the women referred by the police officers did receive help at the CLSC. However, only one third of the women referred did meet with a social practioner following the referral. Also, it was observed that when the period between the referral and the first contact by the social practitioner was short, the women more easily accepted to meet with a worker from the CLSC. A third of the women referred already had a file with the CLSC, which indicated that the violence problem was known in one case out of four. Meeting with a CLSC worker was found to provide a greater diversity in the type of help received
Cervical muscle morphometry and composition demonstrate prognostic value in degenerative cervical myelopathy outcomes
Get PDFObjectivesThis study aimed to examine whether preoperative cervical muscle size, composition, and asymmetry from magnetic resonance imaging (MRI) can predict post-operative outcomes in patients with degenerative cervical myelopathy (DCM).MethodsA total of 171 patients with DCM were included. Relative total cross-sectional area (RCSA), functional CSA (fat-free area, FCSA), ratio of FCSA/CSA (fatty infiltration) and asymmetry of the multifidus (MF) and semispinalis cervicis (SCer) together (MF + SCer), and cervical muscle as a group (MF, SCer, semispinalis capitis, and splenius capitis) were obtained from T2-weighted axial MR images at the mid-disk, at the level of maximum cord compression and the level below. Univariate and multivariate linear regression analyses were used to assess the relationship between baseline cervical muscle measurements of interest with the modified Japanese Orthopedic Association (mJOA), Nurick Classification, Neck Disability Index (NDI), and SF-36 health survey at 6-month and 12-month post-surgery.ResultsLower RCSA of MF + SCer, less CSA MF + SCer asymmetry and greater FCSA/CSA for the cervical muscle group (e.g., less fatty infiltration), and younger age were significant predictors of higher mJOA scores (e.g., less disability) at 6-month and 12-month post-surgery (all p < 0.05). Greater CSA asymmetry in MF + SCer and lower FCSA/CSA (e.g., more fatty infiltration) for the cervical muscle group were significant predictors of higher Nurick scores (e.g., more disability) at 6-month and 12-month post-surgery (all p < 0.05). Lower FCSA MF + Scer asymmetry, lower FCSA/CSA asymmetry of the muscle group, and greater RCSA MF + SCer were significant predictors of higher NDI scores at 6-month and 12-month post-surgery. Finally, greater FCSA/CSA asymmetry of the MF + SCer, greater FCSA asymmetry of the muscle group, greater RCSA of the muscle group, and greater CSA asymmetry of MF + SCer were significant predictors of lower post-operative SF-36 scores at 6- and 12-month post-surgery.ConclusionOur result suggested that cervical paraspinal muscle morphology, specifically greater asymmetry, and fatty infiltration may be important predictors of functional recovery and post-surgical outcomes in patients with DCM
Evaluation of an automated thresholding algorithm for the quantification of paraspinal muscle composition from MRI images
Get PDFAbstract Background The imaging assessment of paraspinal muscle morphology and fatty infiltration has gained considerable attention in the past decades, with reports suggesting an association between muscle degenerative changes and low back pain (LBP). To date, qualitative and quantitative approaches have been used to assess paraspinal muscle composition. Though highly reliable, manual thresholding techniques are time consuming and not always feasible in a clinical setting. The tedious and rater-dependent nature of such manual thresholding techniques provides the impetus for the development of automated or semi-automated segmentation methods. The purpose of the present study was to develop and evaluate an automated thresholding algorithm for the assessment of paraspinal muscle composition. The reliability and validity of the muscle measurements using the new automated thresholding algorithm were investigated through repeated measurements and comparison with measurements from an established, highly reliable manual thresholding technique. Methods Magnetic resonance images of 30 patients with LBP were randomly selected cohort of patients participating in a project on commonly diagnosed lumbar pathologies in patients attending spine surgeon clinics. A series of T2-weighted MR images were used to train the algorithm; preprocessing techniques including adaptive histogram equalization method image adjustment scheme were used to enhance the quality and contrast of the images. All muscle measurements were repeated twice using a manual thresholding technique and the novel automated thresholding algorithm, from axial T2-weigthed images, at least 5 days apart. The rater was blinded to all earlier measurements. Inter-method agreement and intra-rater reliability for each measurement method were assessed. The study did not received external funding and the authors have no disclosures. Results There was excellent agreement between the two methods with inter-method reliability coefficients (intraclass correlation coefficients) varying from 0.79 to 0.99. Bland and Altman plots further confirmed the agreement between the two methods. Intra-rater reliability and standard error of measurements were comparable between methods, with reliability coefficient varying between 0.95 and 0.99 for the manual thresholding and 0.97–0.99 for the automated algorithm. Conclusion The proposed automated thresholding algorithm to assess paraspinal muscle size and composition measurements was highly reliable, with excellent agreement with the reference manual thresholding method
Lumbar multifidus characteristics in university level athletes may be predictors of low back pain and lower limb injury
Get PDFIntroduction: Low back pain (LBP) is highly prevalent in athletes, with decreased lumbar multifidus (LM) crosssectional area (CSA) reported in athletes with LBP and lower limb injury (LLI) as well as decreased LM thickness in athletes with LLI. Previous research has only investigated connections between LM, LBP, and LLI in small samples of athletes in a single sport at a time. This study aimed to (1) examine LM morphology and function across a general sample of male and female university level varsity athletes; (2) investigate whether LM characteristics were predictors of LBP and LLI.Methods: Ultrasound images of LM at L5 were acquired in prone and standing. Body composition was assessed with DEXA and a self-reported questionnaire provided demographics and history of injury. Paired t-tests and independent t-tests compared LM measurements between the sides and sex, respectively. Univariate and multivariate logistic regression analyses were used to assess possible LM characteristic predictors of LBP and LLI.Results: 134 university varsity athletes were evaluated. LM CSA was larger on the non-dominant side in prone. Increased LM thickness was associated with decreased odds of LBP in the previous 4-week (OR=0.49 [0.27, 0.88], p=0.02) and 3-month (OR=0.43 [0.21, 0.89], p=0.02) in the multivariable model, while a greater number of years playing at the university level was associated with increased odds of LBP (OR=1.29 [1.01, 1.65], p=0.04). Greater LM CSA asymmetry (OR=1.14 [1.01, 1.28], p=0.03) and sport (OR=1.44 [1.04, 1.96], p=0.02) were significant predictors of LLI in the previous 12 months.Conclusion: Leg dominance may play a role in unilateral differences. LM thickness and LM CSA asymmetry were predictors of injury. Preseason screening of LM morphology and function could help identify athletes at risk of LBP and LLI, allowing coaches, medical staff, and training staff to target these individuals and provide specific injury prevention programs
Magnetic resonance imaging of human tissue-engineered adipose substitutes
Get PDFAdipose tissue (AT) substitutes are being developed to answer the strong demand in reconstructive surgery. To facilitate the validation of their functional performance in vivo, and to avoid resorting to excessive number of animals, it is crucial at this stage to develop biomedical imaging methodologies, enabling the follow-up of reconstructed AT substitutes. Until now, biomedical imaging of AT substitutes has scarcely been reported in the literature. Therefore, the optimal parameters enabling good resolution, appropriate contrast, and graft delineation, as well as blood perfusion validation, must be studied and reported. In this study, human adipose substitutes produced from adipose-derived stem/stromal cells using the self-assembly approach of tissue engineering were implanted into athymic mice. The fate of the reconstructed AT substitutes implanted in vivo was successfully followed by magnetic resonance imaging (MRI), which is the imaging modality of choice for visualizing soft ATs. T1-weighted images allowed clear delineation of the grafts, followed by volume integration. The magnetic resonance (MR) signal of reconstructed AT was studied in vitro by proton nuclear magnetic resonance (1H-NMR). This confirmed the presence of a strong triglyceride peak of short longitudinal proton relaxation time (T1) values (200±53 ms) in reconstructed AT substitutes (total T1=813±76 ms), which establishes a clear signal difference between adjacent muscle, connective tissue, and native fat (total T1 ∼300 ms). Graft volume retention was followed up to 6 weeks after implantation, revealing a gradual resorption rate averaging at 44% of initial substitute's volume. In addition, vascular perfusion measured by dynamic contrast-enhanced-MRI confirmed the graft's vascularization postimplantation (14 and 21 days after grafting). Histological analysis of the grafted tissues revealed the persistence of numerous adipocytes without evidence of cysts or tissue necrosis. This study describes the in vivo grafting of human adipose substitutes devoid of exogenous matrix components, and for the first time, the optimal parameters necessary to achieve efficient MRI visualization of grafted tissue-engineered adipose substitutes
How inter-rater variability relates to aleatoric and epistemic uncertainty: a case study with deep learning-based paraspinal muscle segmentation
Full text linkRecent developments in deep learning (DL) techniques have led to great
performance improvement in medical image segmentation tasks, especially with
the latest Transformer model and its variants. While labels from fusing
multi-rater manual segmentations are often employed as ideal ground truths in
DL model training, inter-rater variability due to factors such as training
bias, image noise, and extreme anatomical variability can still affect the
performance and uncertainty of the resulting algorithms. Knowledge regarding
how inter-rater variability affects the reliability of the resulting DL
algorithms, a key element in clinical deployment, can help inform better
training data construction and DL models, but has not been explored
extensively. In this paper, we measure aleatoric and epistemic uncertainties
using test-time augmentation (TTA), test-time dropout (TTD), and deep ensemble
to explore their relationship with inter-rater variability. Furthermore, we
compare UNet and TransUNet to study the impacts of Transformers on model
uncertainty with two label fusion strategies. We conduct a case study using
multi-class paraspinal muscle segmentation from T2w MRIs. Our study reveals the
interplay between inter-rater variability and uncertainties, affected by
choices of label fusion strategies and DL models.Comment: Accepted in UNSURE MICCAI 202
Quantitative Magnetic Resonance Imaging Analysis of the Cervical Spine Extensor Muscles: Intrarater and Interrater Reliability of a Novice and an Experienced Rater
Get PDFStudy DesignReliability study.PurposeTo examine the reliability of novice and experienced raters for measurements of the size and composition of the cervical extensor muscles using a thresholding technique.Overview of LiteratureAlthough some authors have reported on the dependability of magnetic resonance imaging (MRI) measurements of the cervical muscles, there remains some variability regarding intrarater and interrater reliabilities, and few studies have examined the associated measurement error. Whether the rater's experience noticeably influences the reliability and precision of such measurements has also not been examined.MethodsA sample of 10 patients with cervical pathologies was selected. Muscle cross-sectional area (CSA), functional cross-sectional area (FCSA), and signal intensity of the cervical extensor muscles were acquired from axial T2-weighted MRIs by a novice and an experienced rater. All measurements were obtained twice, at least 5 days apart, while the raters were blinded to all earlier measurements.ResultsInterrater reliability estimates (intraclass correlation coefficients) varied between 0.84 and 0.99 for the novice rater and between 0.94 and 0.99 for the experienced rater, indicating excellent reliability. The standard error of measurement for the novice rater was, however, noticeably higher for all cervical muscle measurements. Most of the interrater estimates showed excellent agreement with the exception of CSA measurement of the semispinalis cervicis at C4–C7 and FCSA measurement of the multifidus and semispinalis cervicis at C4–C7, which showed poor interrater reliability.ConclusionsThe proposed method of investigating cervical muscle measurements was highly reliable; however, novice raters should receive adequate training before using this method for diagnostic, research, and clinical purposes
Postoperative Assessment of Pedicle Screws and Management of Breaches: A Survey among Canadian Spine Surgeons and a New Scoring System
Get PDFStudy DesignThis study was designed as a survey amongst Canadian spine surgeon to determine a scoring system to standardize pedicle screw placement assessment.PurposeThis study aimed to obtain and analyze the opinions of spine surgeons regarding the assessment of pedicle screw accuracy, with the goal of establishing clinical guidelines for interventions for malpositioned pedicle screws.Overview of LiteratureAccurate placement of pedicle screws is challenging, and misalignment can lead to various complications. To date, there is no recognized gold standard for assessing pedicle screw placement accuracy. The literature is lacking studies attempting to standardize pedicle screw placement accuracy assessment.MethodsA survey of the clinical methods and imaging criteria that are used for assessing pedicle screw placement accuracy was designed and sent to orthopedic and neurosurgery spine surgeons from the Canadian Spine Society for their anonymous participation.ResultsThirty-five surgeons completed the questionnaire. The most commonly used modalities for assessing pedicle screw position postoperatively were plain X-rays (97%) and computed tomography (CT, 97%). In both symptomatic and asymptomatic patients, the most and least worrisome breaches were medial and anterior breaches, respectively. The majority of surgeons tended not to re-operate on asymptomatic breaches. More than 60% of surgeons would re-operate on patients with new-onset pain and a ≤4-mm medial or inferior breach in both thoracic and lumbar regions. If a patient experienced sensory loss and a breach on CT, in either the thoracic or lumbar levels, 90% and 70% of the surgeons would re-operate for a medial breach and an inferior breach, respectively.ConclusionsPostoperative clinical presentation and imaging findings are crucial for interpreting aberrant pedicle screw placement. This study presents a preliminary scoring system for standardizing the classification of pedicle screws
The assessment of paraspinal muscle epimuscular fat in participants with and without low back pain: A case-control study
Get PDFIt remains unclear whether paraspinal muscle fatty infiltration in low back pain (LBP) is i) solely intramuscular, ii) is lying outside the epimysium between the muscle and fascial plane (epimuscular) or iii) or combination of both, as imaging studies often use different segmentation protocols that are not thoroughly described. Epimuscular fat possibly disturbs force generation of paraspinal muscles, but is seldomly explored. This project aimed to 1) compare epimuscular fat in participants with and without chronic LBP, and 2) determine whether epimuscular fat is different across lumbar spinal levels and associated with BMI, age, sex and LBP status, duration or intensity. Fat and water lumbosacral MRIs of 50 chronic LBP participants and 41 healthy controls were used. The presence and extent of epimuscular fat for the paraspinal muscle group (erector spinae and multifidus) was assessed using a qualitative score (0–5 scale; 0 = no epimuscular fat and 5 = epimuscular fat present along the entire muscle) and quantitative manual segmentation method. Chi-squared tests evaluated associations between qualitative epimuscular fat ratings and LBP status at each lumbar level. Bivariate and partial spearman’s rho correlation assessed relationships between quantitative and qualitative epimuscular fat with participants’ characteristics. Epimuscular fat was more frequent at the L4-L5 (X2 = 13.781, p = 0.017) and L5-S1 level (X2 = 27.825, p < 0.001) in participants with LBP compared to controls, which was not found for the higher lumbar levels. The total qualitative score (combined from all levels) showed a significant positive correlation with BMI, age, sex (female) and LBP status (r = 0.23–0.55; p < 0.05). Similarly, the total area of epimuscular fat (quantitative measure) was significantly correlated with BMI, age and LBP status (r = 0.26–0.57; p < 0.05). No correlations were found between epimuscular fat and LBP duration or intensity. Paraspinal muscle epimuscular fat is more common in chronic LBP patients. The functional implications of epimuscular fat should be further explored
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