Pedicled multifidus muscle flaps to treat dural tears due to penetrating spinal stab wounds: Two case reports and a literature review.

Background: Penetrating spinal injuries occasionally lead to dural tears (DT) and cerebrospinal fluid (CSF) leaks that risk both infectious and neurological complications. Here, we reviewed two cases and the literature regarding the safety/efficacy and limitations of repairing traumatic DT utilizing pedicled multifidus muscle flaps. Case Description: Two males, ages 73 and 50, presented with Brown-Sequard syndromes and DT/CSF fistulas attributed to knife-induced spinal injuries at the D3-D4 and D11-D12 levels. Intraoperatively, DT was repaired utilizing pedicle multifidus muscle flaps. Postoperatively, both patients demonstrated partial recovery of neurological function along with no residual symptoms/signs of DT/CSF fistulas. Conclusion: Penetrating traumatic spinal injuries may result in DT/CSF fistulas that can be adequately repaired utilizing pedicle multifidus muscle flaps.

Effects of stress and mental toughness on burnout and depressive symptoms: A prospective study with young elite athletes.

OBJECTIVES: To examine in a sample of young elite athletes (a) the presence of clinically relevant symptoms of burnout and depression, and (b) a possible interaction of perceived stress and mental toughness in the prediction of burnout and depressive symptoms. DESIGN: 6-month prospective study. METHODS: A representative sample of 257 young elite athletes (M=16.82years, SD=1.44, 36% females) was recruited in North-Western Switzerland. 197 athletes were followed-up across a 6-month period. Burnout was assessed with the Shirom-Melamed Burnout Measure (SMBM), and depression with the 9-item depression module of the Patient Health Questionnaire (PHQ). Values of ≥4.40 (SMBM) and >14 (PHQ-9) were considered indicative of clinically relevant burnout or depression. Stress perceptions were assessed with the Perceived Stress Scale (PSS), and mental toughness with the Mental Toughness Questionnaire (MTQ). Hierarchical regression analyses were used to test stress-buffering effects. RESULTS: The percentage of athletes with clinically relevant levels of burnout and depressive symptoms was 12% and 9%, respectively. Both cross-sectional and prospective analyses showed that compared to participants with low mental toughness, those with higher mental toughness scores reported significantly fewer mental health issues, when exposed to high stress. By contrast, when stress levels were low, mental toughness was unrelated to psychological health complaints. CONCLUSIONS: About every tenth young elite athlete reported burnout or depressive symptoms of potential clinical relevance. While high perceived stress was associated with increased psychological health complaints, mental toughness was able to off-set some of the negative consequences resulting from high stress exposure.

Quantitative imaging using high-energy X-ray phase-contrast CT with a 70 kVp polychromatic X-ray spectrum.

Imaging of large and dense objects with grating-based X-ray phase-contrast computed tomography requires high X-ray photon energy and large fields of view. It has become increasingly possible due to the improvements in the grating manufacturing processes. Using a high-energy X-ray phase-contrast CT setup with a large (10 cm in diameter) analyzer grating and operated at an acceleration tube voltage of 70 kVp, we investigate the complementarity of both attenuation and phase contrast modalities with materials of various atomic numbers (Z). We confirm experimentally that for low-Z materials, phase contrast yields no additional information content over attenuation images, yet it provides increased contrast-to-noise ratios (CNRs). The complementarity of both signals can be seen again with increasing Z of the materials and a more comprehensive material characterization is thus possible. Imaging of a part of a human cervical spine with intervertebral discs surrounded by bones and various soft tissue types showcases the benefit of high-energy X-ray phase-contrast system. Phase-contrast reconstruction reveals the internal structure of the discs and makes the boundary between the disc annulus and nucleus pulposus visible. Despite the fact that it still remains challenging to develop a high-energy grating interferometer with a broad polychromatic source with satisfactory optical performance, improved image quality for phase contrast as compared to attenuation contrast can be obtained and new exciting applications foreseen.

Experimental results from a preclinical X-ray phase-contrast CT scanner.

To explore the future clinical potential of improved soft-tissue visibility with grating-based X-ray phase contrast (PC), we have developed a first preclinical computed tomography (CT) scanner featuring a rotating gantry. The main challenge in the transition from previous bench-top systems to a preclinical scanner are phase artifacts that are caused by minimal changes in the grating alignment during gantry rotation. In this paper, we present the first experimental results from the system together with an adaptive phase recovery method that corrects for these phase artifacts. Using this method, we show that the scanner can recover quantitatively accurate Hounsfield units in attenuation and phase. Moreover, we present a first tomography scan of biological tissue with complementary information in attenuation and phase contrast. The present study hence demonstrates the feasibility of grating-based phase contrast with a rotating gantry for the first time and paves the way for future in vivo studies on small animal disease models (in the mid-term future) and human diagnostics applications (in the long-term future).

Development of a prototype gantry system for preclinical x-ray phase-contrast computed tomography.

PURPOSE: To explore the potential of grating-based x-ray phase-contrast imaging for clinical applications, a first compact gantry system was developed. It is designed such that it can be implemented into an in-vivo small-animal phase-contrast computed tomography (PC-CT) scanner. The purpose of the present study is to assess the accuracy and quantitativeness of the described gantry in both absorption and phase-contrast. METHODS: A phantom, containing six chemically well-defined liquids, was constructed. A tomography scan with cone-beam reconstruction of this phantom was performed yielding the spatial distribution of the linear attenuation coefficient µ and decrement δ of the complex refractive index. Theoretical values of µ and δ were calculated for each liquid from tabulated data and compared with the experimentally measured values. Additionally, a color-fused image representation is proposed to display the complementary absorption and phase-contrast information in a single image. RESULTS: Experimental and calculated data of the phantom agree well confirming the quantitativeness and accuracy of the reconstructed spatial distributions of µ and δ. The proposed color-fused image representation, which combines the complementary absorption and phase information, considerably helps in distinguishing the individual substances. CONCLUSIONS: The concept of grating-based phase-contrast computed tomography (CT) can be implemented into a compact, cone-beam geometry gantry setup. The authors believe that this work represents an important milestone in translating phase-contrast x-ray imaging from previous proof-of-principle experiments to first preclinical biomedical imaging applications on small-animal models.