3D reconstruction of long bones utilising magnetic resonance imaging (MRI)

The design of pre-contoured fracture fixation implants (plates and nails) that correctly fit the anatomy of a patient utilises 3D models of long bones with accurate geometric representation. 3D data is usually available from computed tomography (CT) scans of human cadavers that generally represent the above 60 year old age group. Thus, despite the fact that half of the seriously injured population comes from the 30 year age group and below, virtually no data exists from these younger age groups to inform the design of implants that optimally fit patients from these groups. Hence, relevant bone data from these age groups is required. The current gold standard for acquiring such data–CT–involves ionising radiation and cannot be used to scan healthy human volunteers. Magnetic resonance imaging (MRI) has been shown to be a potential alternative in the previous studies conducted using small bones (tarsal bones) and parts of the long bones. However, in order to use MRI effectively for 3D reconstruction of human long bones, further validations using long bones and appropriate reference standards are required. Accurate reconstruction of 3D models from CT or MRI data sets requires an accurate image segmentation method. Currently available sophisticated segmentation methods involve complex programming and mathematics that researchers are not trained to perform. Therefore, an accurate but relatively simple segmentation method is required for segmentation of CT and MRI data. Furthermore, some of the limitations of 1.5T MRI such as very long scanning times and poor contrast in articular regions can potentially be reduced by using higher field 3T MRI imaging. However, a quantification of the signal to noise ratio (SNR) gain at the bone - soft tissue interface should be performed; this is not reported in the literature. As MRI scanning of long bones has very long scanning times, the acquired images are more prone to motion artefacts due to random movements of the subject‟s limbs. One of the artefacts observed is the step artefact that is believed to occur from the random movements of the volunteer during a scan. This needs to be corrected before the models can be used for implant design. As the first aim, this study investigated two segmentation methods: intensity thresholding and Canny edge detection as accurate but simple segmentation methods for segmentation of MRI and CT data. The second aim was to investigate the usability of MRI as a radiation free imaging alternative to CT for reconstruction of 3D models of long bones. The third aim was to use 3T MRI to improve the poor contrast in articular regions and long scanning times of current MRI. The fourth and final aim was to minimise the step artefact using 3D modelling techniques. The segmentation methods were investigated using CT scans of five ovine femora. The single level thresholding was performed using a visually selected threshold level to segment the complete femur. For multilevel thresholding, multiple threshold levels calculated from the threshold selection method were used for the proximal, diaphyseal and distal regions of the femur. Canny edge detection was used by delineating the outer and inner contour of 2D images and then combining them to generate the 3D model. Models generated from these methods were compared to the reference standard generated using the mechanical contact scans of the denuded bone. The second aim was achieved using CT and MRI scans of five ovine femora and segmenting them using the multilevel threshold method. A surface geometric comparison was conducted between CT based, MRI based and reference models. To quantitatively compare the 1.5T images to the 3T MRI images, the right lower limbs of five healthy volunteers were scanned using scanners from the same manufacturer. The images obtained using the identical protocols were compared by means of SNR and contrast to noise ratio (CNR) of muscle, bone marrow and bone. In order to correct the step artefact in the final 3D models, the step was simulated in five ovine femora scanned with a 3T MRI scanner. The step was corrected using the iterative closest point (ICP) algorithm based aligning method. The present study demonstrated that the multi-threshold approach in combination with the threshold selection method can generate 3D models from long bones with an average deviation of 0.18 mm. The same was 0.24 mm of the single threshold method. There was a significant statistical difference between the accuracy of models generated by the two methods. In comparison, the Canny edge detection method generated average deviation of 0.20 mm. MRI based models exhibited 0.23 mm average deviation in comparison to the 0.18 mm average deviation of CT based models. The differences were not statistically significant. 3T MRI improved the contrast in the bone–muscle interfaces of most anatomical regions of femora and tibiae, potentially improving the inaccuracies conferred by poor contrast of the articular regions. Using the robust ICP algorithm to align the 3D surfaces, the step artefact that occurred by the volunteer moving the leg was corrected, generating errors of 0.32 ± 0.02 mm when compared with the reference standard. The study concludes that magnetic resonance imaging, together with simple multilevel thresholding segmentation, is able to produce 3D models of long bones with accurate geometric representations. The method is, therefore, a potential alternative to the current gold standard CT imaging.

In vitro estimation of foetal liver volume using ultrasound, x-ray computed tomography and magnetic resonance imaging

Sixteen formalin-fixed foetal livers were scanned in vitro using a new system for estimating volume from a sequence of multiplanar 2D ultrasound images. Three different scan techniques were used (radial, parallel and slanted) and four volume estimation algorithms (ellipsoid, planimetry, tetrahedral and ray tracing). Actual liver volumes were measured by water displacement. Twelve of the sixteen livers also received x-ray computed tomography (CT) and magnetic resonance (MR) scans and the volumes were calculated using voxel counting and planimetry. The percentage accuracy (mean ± SD) was 5.3 ± 4.7%, −3.1 ± 9.6% and −0.03 ± 9.7% for ultrasound (radial scans, ray volumes), MR and CT (voxel counting) respectively. The new system may be useful for accurately estimating foetal liver volume in utero.

Is –110°C cold air cryotherapy effective in improving post-exercise recovery in sports people?

Whole body cryotherapy (WBC) involves repeatedly exposing an individual, dressed in minimal clothing, to extremely cold air (–100 to –130°C) for a short period. One specific claim that is often made is that WBC is effective in treating exercise-induced muscle soreness and damage. However, our results suggest that two bouts of WBC were ineffective in improving recovery from eccentric exercise when administered 24 hours after eccentric exercise.

Double diffusive magneto-convection fluid flow in a strong cross magnetic field with uniform surface heat and mass flux

In this study, magnetohydrodynamic natural convection boundary layer flow of an electrically conducting and viscous incompressible fluid along a heated vertical flat plate with uniform heat and mass flux in the presence of strong cross magnetic field has been investigated. For smooth integrations the boundary layer equations are transformed in to a convenient dimensionless form by using stream function formulation as well as the free variable formulation. The nonsimilar parabolic partial differential equations are integrated numerically for Pr ≪1 that is appropriate for liquid metals against the local Hartmann parameter ξ . Further, asymptotic solutions are obtained near the leading edge using regular perturbation method for smaller values of ξ . Solutions for values of ξ ≫ 1 are also obtained by employing the matched asymptotic technique. The results obtained for small, large and all ξ regimes are examined in terms of shear stress, τw, rate of heat transfer, qw, and rate of mass transfer, mw, for important physical parameter. Attention has been given to the influence of Schmidt number, Sc, buoyancy ratio parameter, N and local Hartmann parameter, ξ on velocity, temperature and concentration distributions and noted that velocity and temperature of the fluid achieve their asymptotic profiles for Sc ≥ 10:0.

Microstructural magnetic resonance imaging of articular cartilage

The focus of this Editorial is recent developments in magnetic resonance imaging (MRI) modalities for evaluation of the microstructure and macromolecular organisation of articular cartilage. We place a specific emphasis on three types of measurements: (1) MRI transverse spin-relaxation mapping (T2 mapping); (2) diffusion-tensor imaging; and (3) compression micro-MRI (uMRI) measurements of articular cartilage in vitro. Such studies have a significant role to play in improving the understanding of the fundamental biomechanics of articular cartilage and in the development of in vitro models of early osteoarthritis. We discuss how the supramolecular organisation of the cartilage extracellular matrix and its behaviour under mechanical compression can be inferred from diffusion-tensor and T2 maps with in-plane resolution ~100 um. The emphasis is on in vitro studies performed under controlled physiological conditions but in vivo applications of T2 mapping and DTI are also briefly discussed.

Cytokine responses to carbohydrate ingestion during recovery from exercise-induced muscle injury.

We investigated the effect of carbohydrate ingestion after maximal lengthening contractions of the knee extensors on circulating concentrations of myocellular proteins and cytokines, and cytokine mRNA expression in muscle. Using a cross-over design, 10 healthy males completed 5 sets of 10 lengthening (eccentric) contractions (unilateral leg press) at 120% 1 repetition-maximum. Subjects were randomized to consume a carbohydrate drink (15% weight per volume; 3 g/kg BM) for 3 h after exercise using one leg, or a placebo drink after exercise using the contralateral leg on another day. Blood samples (10 mL) were collected before exercise and after 0, 30, 60, 90, 120, 150, and 180 min of recovery. Muscle biopsies (vastus lateralis) were collected before exercise and after 3 h of recovery. Following carbohydrate ingestion, serum concentrations of glucose (30-90 min and at 150 min) and insulin (30-180 min) increased (P < 0.05) above pre-exercise values. Serum myoglobin concentration increased (similar to 250%; P < 0.05) after both trials. In contrast, serum cytokine concentrations were unchanged throughout recovery in both trials. Muscle mRNA expression for IL-8 (6.4-fold), MCP-1 (4.7-fold), and IL-6 (7.3-fold) increased substantially after carbohydrate ingestion. TNF-alpha mRNA expression did not change after either trial. Carbohydrate ingestion during early recovery from exercise-induced muscle injury may promote proinflammatory reactions within skeletal muscle.

Effects of acute multinutrient supplementation on rugby union game performance and recovery

Purpose: To investigate the effects of an acute multinutrient supplement on game-based running performance, peak power output, anaerobic by-products, hormonal profiles, markers of muscle damage, and perceived muscular soreness before, immediately after, and 24 h following competitive rugby union games. Methods: Twelve male rugby union players ingested either a comprehensive multinutrient supplement (SUPP), [RE-ACTIVATE:01], or a placebo (PL) for 5 d. Participants then performed a competitive rugby union game (with global positioning system tracking), with associated blood draws and vertical jump assessments pre, immediately post and 24 h following competition. Results: SUPP ingestion resulted in moderate to large effects for augmented 1st half very high intensity running (VHIR) mean speed (5.9 ± 0.4 vs 4.8 ± 2.3 m·min–1; d= 0.93). Further, moderate increases in 2nd half VHIR distance (137 ± 119 vs 83 ± 89 m; d= 0.73) and VHIR mean speed (5.9 ± 0.6 v 5.3 ± 1.7 m·min–1; d= 0.56) in SUPP condition were also apparent. Postgame aspartate aminotransferase (AST; 44.1 ± 11.8 vs 37.0 ± 3.2 UL; d= 1.16) and creatine kinase (CK; 882 ± 472 vs. 645 ± 123 UL; d= 0.97) measures demonstrated increased values in the SUPP condition, while AST and CK values correlated with 2nd half VHIR distance (r= –0.71 and r= –0.76 respectively). Elevated C-reactive protein (CRP) was observed postgame in both conditions; however, it was significantly blunted with SUPP (P= .05). Conclusions: These findings suggest SUPP may assist in the maintenance of VHIR during rugby union games, possibly via the buffering qualities of SUPP ingredients. However, correlations between increased work completed at very high intensities and muscular degradation in SUPP conditions, may mask any anticatabolic properties of the supplement.

The effect of post-match alcohol ingestion on recovery from competitive Rugby League matches

This study investigated the effects of alcohol ingestion on lower body strength and power, and physiological and cognitive recovery following competitive Rugby League matches. Nine male Rugby players participated in two matches, followed by one of two randomized interventions; a control or alcohol ingestion session. Four hours post-match, participants consumed either beverages containing a total of 1g of ethanol per kg bodyweight (vodka and orange juice; ALC) or a caloric and taste matched non-alcoholic beverage (orange juice; CONT). Pre, post, 2 h post and 16 h post match measures of countermovement jump (CMJ), maximal voluntary contraction(MVC), voluntary activation (VA), damage and stress markers of creatine kinase (CK), C-reactive protein (CRP), cortisol, and testosterone analysed from venous blood collection, and cognitive function (modified Stroop test) were determined. Alcohol resulted in large effects for decreased CMJ height(-2.35 ± 8.14 and -10.53 ± 8.36 % decrement for CONT and ALC respectively; P=0.15, d=1.40), without changes in MVC (P=0.52, d=0.70) or VA (P=0.15, d=0.69). Furthermore, alcohol resulted in a significant slowing of total time in a cognitive test (P=0.04, d=1.59), whilst exhibiting large effects for detriments in congruent reaction time (P=0.19, d=1.73). Despite large effects for increased cortisol following alcohol ingestion during recovery (P=0.28, d=1.44), post-match alcohol consumption did not unduly affect testosterone (P-0.96, d=0.10), CK (P=0.66, d=0.70) or CRP(P=0.75, d=0.60). It appears alcohol consumption during the evening following competitive rugby matches may have some detrimental effects on peak power and cognitive recovery the morning following a Rugby League match. Accordingly, practitioners should be aware of the potential associated detrimental effects of alcohol consumption on recovery and provide alcohol awareness to athletes at post-match functions.

Effects of mixed-method cooling on recovery of medium-fast bowling performance in hot conditions on consecutive days

This investigation examined physiological and performance effects of cooling on recovery of medium-fast bowlers in the heat. Eight, medium-fast bowlers completed two randomised trials, involving two sessions completed on consecutive days (Session 1: 10-overs and Session 2: 4-overs) in 31 ± 3°C and 55 ± 17% relative humidity. Recovery interventions were administered for 20 min (mixed-method cooling vs. control) after Session 1. Measures included bowling performance (ball speed, accuracy, run-up speeds), physical demands (global positioning system, counter-movement jump), physiological (heart rate, core temperature, skin temperature, sweat loss), biochemical (creatine kinase, C-reactive protein) and perceptual variables (perceived exertion, thermal sensation, muscle soreness). Mean ball speed was higher after cooling in Session 2 (118.9 ± 8.1 vs. 115.5 ± 8.6 km · h−1; P = 0.001; d = 0.67), reducing declines in ball speed between sessions (0.24 vs. −3.18 km · h−1; P = 0.03; d = 1.80). Large effects indicated higher accuracy in Session 2 after cooling (46.0 ± 11.2 vs. 39.4 ± 8.6 arbitrary units [AU]; P = 0.13; d = 0.93) without affecting total run-up speed (19.0 ± 3.1 vs. 19.0 ± 2.5 km · h−1; P = 0.97; d = 0.01). Cooling reduced core temperature, skin temperature and thermal sensation throughout the intervention (P = 0.001–0.05; d = 1.31–5.78) and attenuated creatine kinase (P = 0.04; d = 0.56) and muscle soreness at 24-h (P = 0.03; d = 2.05). Accordingly, mixed-method cooling can reduce thermal strain after a 10-over spell and improve markers of muscular damage and discomfort alongside maintained medium-fast bowling performance on consecutive days in hot conditions.

Narrative : family trauma or challenge and resilience in the Galapagos Archipelago

The chapter is a "here and now" narration in the first person as witnessed and experienced by the author during field work in the Galapagos Islands in 1976-79. The story begins on the most remote volcanic island of Fernandina where the breeding biology of Flightless cormorants was being studied. A small selection of the many potentially life threatening situations and challenges is described including stories related to the birth of their son.

Effects of acute multi-nutrient supplementation on rugby union match performance and recovery

Aim: To determine the effects of an acute multi-nutrient supplement on physiological, performance and recovery responses to intermittent-sprint running and muscular damage during rugby union matches. Methods: Using a randomised, double-blind, cross-over design, twelve male rugby union players ingested either 75 g of a comprehensive multi-nutrient supplement (SUPP), [Musashi] or 1 g of a taste and carbohydrate matched placebo (PL) for 5 days pre-competition. Competitive rugby union game running performance was then measured using 1 Hz GPS data (SPI10, SPI elite, GPSports), in addition to associated blood draws, vertical jump assessments and ratings of perceived muscular soreness (MS) pre, immediately post and 24 h post-competition. Baseline (BL) GPS data was collected during six competition rounds preceding data collection. Results: No significant differences were observed between supplement conditions for all game running, vertical jump, and ratings of perceived muscular soreness. However, effect size analysis indicated SUPP ingestion increased 1st half very high intensity running (VHIR) mean speed (d = 0.93) and 2nd half relative distance (m/min) (d = 0.97). Further, moderate increases in 2nd half VHIR distance (d = 0.73), VHIR m/min (d = 0.70) and VHIR mean speed (d = 0.56) in SUPP condition were also apparent. Moreover, SUPP demonstrated significant increases in 2nd half dist m/min, total game dist m/min and total game HIR m/min compared with BL data (P < 0.05). Further, large ES increases in VHIR time (d = 0.88) and moderate increases in 2nd half HIR m/min (d = 0.65) and 2nd half VHIR m/min (d = 0.74) were observed between SUPP and BL. Post-game aspartate aminotransferase (AST) (d = 1.16) and creatine kinase (CK) (d = 0.97) measures demonstrated increased ES values with SUPP, while AST and CK values correlated with 2nd half VHIR distance (r = −0.71 and r = −0.76 respectively). Elevated c-reactive protein (CRP) was observed post-game in both conditions, however was significantly blunted with SUPP (P = 0.05). Additionally, pre-game (d = 0.98) and post-game (d = 0.96) increases in cortisol (CORT) were apparent with SUPP. No differences were apparent between conditions for pH, lactate, glucose, HCO3, vertical jump assessments and MS (P > 0.05). Conclusion: These findings suggest SUPP may assist in the maintenance of VHIR speeds and distances covered during rugby union games, possibly via the buffering qualities of SUPP ingredients (i.e. caffeine, creatine, bicarbonate). While the mechanisms for these findings are unclear, the similar pH between conditions despite additional VHIR during SUPP may support this conclusion. Finally, correlations between increased work completed at very high intensities and muscular degradation in SUPP conditions, may mask any anti-catabolic properties of supplementation.

Making sense of mental illness as a full human experience : Perspective of illness and recovery held by people with a mental illness living in the community.

Recovery is a highly contextualized concept amid divergent interpretations and unique experiences. There is substantial current interest in building evidence about recovery from mental illness in order to inform best practice founded in the ways people find to live productive and meaningful lives. This paper presents some accounts related to recovery and illness expressed by eight people through a Participatory Action Research project. The research facilitated entry to the subjective experiences of living in the community as an artist with a mental illness. The people in the research shared an integrated understanding of illness, recovery and identity. Their understanding provided insight into mental illness as an inseparable aspect of who they were. Further, specific issue was raised of recovery as a clinical term with a requirement to meet distinct conventions of recovery. This paper emphasizes that being ill and being well, for the person with a mental illness, is a dynamic and complex development not easily explained or transformed into uniform process or outcomes. Attempts to establish an integral or consensual approach to recovery has, to date, disregarded mental illness as a full human experience. This paper argues that broader frameworks for thinking and responding to the dynamic processes of mental illness and recovery are needed and require acknowledgment of competing and contradictory ideas.