Effect of inflow and outflow angles on the computational hemodynamics in abdominal aortic aneurysm

To help with the clinical screening and diagnosis of abdominal aortic aneurysm (AAA), we evaluated the effect of inflow angle (IA) and outflow bifurcation angle (BA) on the distribution of blood flow and wall shear stress (WSS) in an idealized AAA model. A 2D incompressible Newtonian flow is assumed and the computational simulation is performed using finite volume method. The results showed that the largest WSS often located at the proximal and the distal end of the AAA. An increase in IA resulted in an increase in maximum WSS. We also found that WSS was maximal when BA was 90°. IA and BA are two important geometrical factors, they may help with AAA risk assessment along with the commonly used AAA diameter.

Utility of magnetic resonance imaging-based finite element analysis for the biomechanical stress analysis of hemorrhagic and non-hemorrhagic carotid plaques

Background: Biomechanical stress analysis has been used for plaque vulnerability assessment. The presence of plaque hemorrhage (PH) is a feature of plaque vulnerability and is associated with thromboembolic ischemic events. The purpose of the present study was to use finite element analysis (FEA) to compare the stress profiles of hemorrhagic and non-hemorrhagic profiles. Methods and Results: Forty-five consecutive patients who had suffered a cerebrovascular ischemic event with an underlying carotid artery disease underwent high-resolution magnetic resonance imaging (MRI) of their symptomatic carotid artery in a 1.5-T MRI system. Axial images were manually segmented for various plaque components and used for FEA. Maximum critical stress (M-CstressSL) for each slice was determined. Within a plaque, the maximum M-CstressSL for each slice of a plaque was selected to represent the maximum critical stress of that plaque (M-CstressPL) and used to compare hemorrhagic and non-hemorrhagic plaques. A total of 62% of plaques had hemorrhage. It was observed that plaques with hemorrhage had significantly higher stress (M-CstressPL) than plaques without PH (median [interquartile range]: 315 kPa [247-434] vs. 200 kPa [171-282], P=0.003). Conclusions: Hemorrhagic plaques have higher biomechanical stresses than non-hemorrhagic plaques. MRI-based FEA seems to have the potential to assess plaque vulnerability.

Finite element analysis of vulnerable atherosclerotic plaques: A comparison of mechanical stresses within carotid plaques of acute and recently symptomatic patients with carotid artery disease

Objectives: There is considerable evidence that patients with carotid artery stenosis treated immediately after the ischaemic cerebrovascular event have a better clinical outcome than those who have delayed treatment. Biomechanical assessment of carotid plaques using high-resolution MRI can help examine the relationship between the timing of carotid plaque symptomology and maximum simulated plaque stress concentration. Methods: Fifty patients underwent high-resolution multisequence in vivo MRI of their carotid arteries. Patients with acute symptoms (n=25) underwent MRI within 72 h of the onset of ischaemic cerebrovascular symptoms, whereas recently symptomatic patients (n=25) underwent MRI from 2 to 6 weeks after the onset of symptoms. Stress analysis was performed based on the geometry derived from in vivo MRI of the symptomatic carotid artery at the point of maximum stenosis. The peak stresses within the plaques of the two groups were compared. Results: Patient demographics were comparable for both groups. All the patients in the recently symptomatic group had severe carotid stenosis in contrast to patients with acute symptoms who had predominantly mild to moderate carotid stenosis. The simulated maximum stresses in patients with acute symptoms was significantly higher than in recently symptomatic patients (median (IQR): 313310 4 dynes/cm 2 (295 to 382) vs 2523104 dynes/cm 2 (236 to 311), p=0.02). Conclusions: Patients have extremely unstable, high-risk plaques, with high stresses, immediately after an acute cerebrovascular event, even at lower degrees of carotid stenoses. Biomechanical stress analysis may help us refine our risk-stratification criteria for the management of patients with carotid artery disease in future.

Utility of USPIO-enhanced MR imaging to identify inflammation and the fibrous cap: A comparison of symptomatic and asymptomatic individuals

Background and purpose: Inflammation is a risk factor the vulnerable atheromatous plaque. This can be detected in vivo on high-resolution magnetic resonance (MR) imaging using a contrast agent, Sinerem™, an ultra-small super-paramagnetic iron oxide (USPIO). The aim of this study was to explore whether there is a difference in the degree of MR defined inflammation using USPIO particles, between symptomatic and asymptomatic carotid plaques. We report further on its T1 effect of enhancing the fibrous cap, which may allow dual contrast resolution of carotid atheroma. Methods: Twenty patients with carotid stenosis (10 symptomatic and 10 asymptomatic) underwent multi-sequence MR imaging before and 36 h post-USPIO infusion. Images were manually segmented into quadrants and signal change in each quadrant was calculated following USPIO administration. Mean signal change across all quadrants were compared between the two groups. Results: Symptomatic patients had significantly more quadrants with a signal drop than asymptomatic individuals (75% vs. 32%, p < 0.01). Asymptomatic plaques had more quadrants with signal enhancement than symptomatic ones (68% vs. 25%, p < 0.05); their mean signal change was also higher (46% vs. 15%, p < 0.01) and this appeared to correlate with a thicker fibrous cap on histology. Conclusions: Symptomatic patients had more quadrants with signal drop suggesting larger inflammatory infiltrates. Asymptomatic individuals showed significantly more enhancement possibly suggesting greater stability as a result of thicker fibrous caps. However, some asymptomatic plaques also had focal areas of signal drop, suggesting an occult macrophage burden. If validated by larger studies, USPIO may be a useful dual contrast agent able to improve risk stratification of patients with carotid stenosis and inform selection for intervention.

Impact of calcification and intraluminal thrombus on the computed wall stresses of abdominal aortic aneurysm

Background: Increased biomechanical stresses within the abdominal aortic aneurysm (AAA) wall contribute to its rupture. Calcification and intraluminal thrombus can be commonly found in AAAs, but the relationship between calcification/intraluminal thrombus and AAA wall stress is not completely described. Methods: Patient-specific three-dimensional AAA geometries were reconstructed from computed tomographic images of 20 patients. Structural analysis was performed to calculate the wall stresses of the 20 AAA models and their altered models when calcification or intraluminal thrombus was not considered. A nonlinear large-strain finite element method was used to compute the wall stress distribution. The relationships between wall stresses and volumes of calcification and intraluminal thrombus were sought. Results: Maximum stress was not correlated with the percentage of calcification, and was negatively correlated with the percentage of intraluminal thrombus (r = -0.56; P = .011). Exclusion of calcification from analysis led to a significant decrease in maximum stress by a median of 14% (range, 2%-27%; P < .01). When intraluminal thrombus was eliminated, maximum stress increased significantly by a median of 24% (range, 5%-43%; P < .01). Conclusion: The presence of calcification increases AAA peak wall stress, suggesting that calcification decrease the biomechanical stability of AAA. In contrast, intraluminal thrombus reduces the maximum stress in AAA. Calcification and intraluminal thrombus should both be considered in the evaluation of wall stress for risk assessment of AAA rupture.

Evaluation of growth and changes in body composition following neonatal diagnosis of cystic fibrosis

Early deficits in nutritional status that might require specific treatment and early response to nutritional therapy were studied longitudinally in 25 infants with cystic fibrosis (CF) diagnosed by neonatal screening, using anthropometric and research body composition methodology, and evaluation of pancreatic function. At the time of confirmed diagnosis (mean 5.4 weeks), body mass, length, total body fat (TBF), and total body potassium (TBK) were all significantly reduced. Following diagnosis and commencement of therapy there was a normalization of weight, length, and TBK by 6-12 months of age, indicating catch-up growth. But in some individuals the response was incomplete, and as a group, mean total body fat remained significantly lower than normal at 1 year of age. Seven of 25 (28%) were pancreatic sufficient at diagnosis, and all but one had evidence of declining pancreatic function requiring the institution of pancreatic enzyme therapy during the next 1-9 months. The median age of commencement of enzyme therapy was 10 weeks (range 5 weeks to 11 months). These longitudinal assessments emphasize the dynamic changes occurring in absorptive function, body composition, and nutritional status following neonatal diagnosis of cystic fibrosis and may reflect previously described abnormalities of energy metabolism in this age group. Abnormal body composition is evident in most CF infants following diagnosis by neonatal screening but pancreatic damage may still be evolving. We suggest that early active nutritional therapy and surveillance for changes in pancreatic function are warranted in CF infants diagnosed by neonatal screening.

Protein turnover in malnourished patients with cystic fibrosis: Effects of elemental and nonelemental nutritional supplements

To evaluate the relative efficacy of nonele-mental versus semielemental enteral supplements for nutritional rehabilitation of cystic fibrosis (CF) patients, whole-body protein turnover using the [15N]glycine method was studied in nine malnourished CF patients during enteral feedings, in a block design study compar-ing a semielemental formula (Criticare), a higher protein density but nonelemental formula (Traumacal) (T), and a nonelemental formula that had been modified to become isocaloric and isonitrogenous to the semielemental formula (modified Traumacal, MT). No significant differences in rates of protein synthesis or catabolism were observed comparing the three formulas. However the higher protein density nonelemental formula resulted in higher net protein deposition compared to the other two formulas (T + 0.42 g kg-110 h-1versus 0.33 g kg-110 h-1for Criticare and-0.59 g kg-110 h-1for MT), although this was significant (p < 0.05) for the MT versus T comparison only. This study lends support to the use of less expensive nonelemental formulas for the nutritional management of malnourished patients with CF. © 1990 Raven Press Ltd, New York.

Improving the outcomes of foot and ankle surgery. Professional impact of the Australasian College of Podiatric Surgeons' audit tool

Background Surgery is an example of expanded practice scope that enhances podiatry and incorporates inter-professional collaboration. By 2050 demand for foot and ankle procedures is predicted to rise nationally by 61.9%. Performance management of this increase motivated the development of an online audit tool. Developed in collaboration with the Australasian College of Podiatric Surgeons (ACPS), the ACPS audit tool provides real-time data capture and reporting. It is the first audit tool designed in Australia to support and improve the outcomes of foot and ankle surgery. Methods Audit activity in general, orthopaedic, plastic and podiatric surgery was examined using a case study design. Audit participation enablers and barriers were explored. Case study results guided a Delphi survey of international experts experienced or associated with foot and ankle surgery. Delphi survey-derived consensus informed modification of a generic data set from the Royal Australasian College of Surgeons (RACS). Based on the Delphi survey findings the ACPS online audit tool was developed and piloted. Reliability and validity of data entry and usability of this new tool was then assessed with an online survey. Results The case study found surgeon attitudes and behaviours positively impacted audit participation, and also indicated that audit data should be: (1) available in real time, (2) identify practice change, (3) applicable for safety and quality management, and; (4) useful for peer review discussion. The Delphi process established consensus on audit variables to be captured, including the modified RACS generic data set. 382 cases of foot and ankle surgery were captured across 3 months using the new tool. Data entry was found to be valid and reliable. Real-time outcome reporting and practice change identification impacted positively on safety and quality management and assisted peer review discussion. An online survey showed high levels of usability. Conclusions Surgeon contribution to audit tool development resulted in 100% audit participation. The data from the ACPS audit tool supported the ACPS submission to the Medical Services Advisory Committee to list podiatric surgery under Medicare, an outcome noted by the Federal Minister of Health.

The effects of psychosocial factors on the emotional well-being of women during pregnancy: A cross-cultural study of Britain and Greece

The effects of life events, social support and the emotional well-being of partner on the emotional well-being of the mother during pregnancy was examined within the cultural contexts of Britain and Greece. It was proposed that social support, impact of life events and relationship of the mother with her partner would be affected by the different social structures of each culture and would influence emotional well-being. A sample of 200 Greek and 156 British mothers and their partners completed questionnaires which included a life event inventory, measure of social support and measure of emotional well-being (Crown-Crisp Experiential Index). Greek mothers were found to score significantly higher on measures of depression, anxiety and somaticism, experience more stressful life events (most relating to family issues) and report feeling less supported than British mothers. Life events, particularly those relating to family stresses were found to predict poor emotional well-being among Greek mothers. For British mothers, social support was the strongest predictor of emotional well-being. Findings were discussed in the light of differences in social structure and it was suggested that future research might focus on the disruption of established social support structures rather than the differences in availability of social support per se when considering maternal emotional well-being.

The effects of psychosocial factors on the mother's emotional well-being during early parenthood: A cross-cultural study of Britain and Greece

The effect of psychosocial factors on the emotional well-being of mothers following childbirth were examined within the cultural contexts of Britain and Greece. These mothers had already completed questionnaires during pregnancy and were contacted a second time in the postpartum period. At 4–6 weeks postpartum a sample of 165 Greek mothers and 101 British mothers and their partners completed the Edinburgh Postnatal Depression Scale. The relationship between mothers' EPDS scores and measures of emotional well-being in pregnancy (CCEI), social support, life events, fathers' EPDS score, and father's perception of change in partner was examined in each culture. No difference in the distribution of EPDS scores in each culture was found. Social support and life events were found to predict postnatal depression in both cultures. Additionally, in Greece, emotional well-being in pregnancy made a separate contribution to prediction. The major difference between the two cultures was in the relationship between mothers and their partners. Greek fathers were more emotionally and physically distanced from their partners during pregnancy, birth and early parenthood and perceived their partners as being more changed by the transition to parenthood. These differences were not reflected in differences in emotional well-being possibly because they accord with social expectation in each culture.

Comparison of prevalence of depression in mothers of twins and mothers of singletons

OBJECTIVE To determine whether the apparent additional and exceptional stresses associated with bearing and parenting twins affect the emotional wellbeing of mothers. SETTING--Great Britain, 1970-5. DESIGN Cohort study of 13,135 children born between 4 April and 11 April 1970. Mothers of all children, both singletons and twins, were interviewed by health visitors (providing demographic data) and completed a self report measure of emotional well-being (the Rutter malaise inventory) when the child was 5 years of age. The malaise scores of mothers of twins were compared with those of all mothers of singletons and then with those of mothers categorised by the age spacing of their children (only one child, widely spaced, or closely spaced), taking account of maternal age, social class, and whether the study child had a disability, by using logistic regression. SUBJECTS 139 mothers of twins--122 pairs of twins and 17 twins whose cotwin had died--and 12,573 controls, who were mothers of singletons. RESULTS A significantly higher proportion of mothers of twins at 5 years had malaise scores indicative of depression than mothers of singletons at the same age. Mothers who had borne twins, one of whom had subsequently died, had the highest malaise scores and were three times more likely than mothers of singletons to experience depression. Both mothers of twin pairs and mothers of singletons closely spaced in age were at significantly higher risk of experiencing depression than mothers of children widely spaced in age or mothers of only one child (p less than 0.0001). Odds ratios indicated that the risk of depression in mothers of twins was higher than that in mothers of closely spaced singletons. CONCLUSION Mothers of twins are more likely to experience depression. This suggests a relation between the additional and exceptional stresses that twins present and the mother's emotional wellbeing.

The impact of inter-fraction set-up errors on the probability of pulmonary and cardiac complication in left-sided breast cancer patients

Purpose This study evaluated the impact of patient set-up errors on the probability of pulmonary and cardiac complications in the irradiation of left-sided breast cancer. Methods and Materials Using the CMS XiO Version 4.6 (CMS Inc., St Louis, MO) radiotherapy planning system's NTCP algorithm and the Lyman -Kutcher-Burman (LKB) model, we calculated the DVH indices for the ipsilateral lung and heart and the resultant normal tissue complication probabilities (NTCP) for radiation-induced pneumonitis and excess cardiac mortality in 12 left-sided breast cancer patients. Results Isocenter shifts in the posterior direction had the greatest effect on the lung V20, heart V25, mean and maximum doses to the lung and the heart. Dose volume histograms (DVH) results show that the ipsilateral lung V20 tolerance was exceeded in 58% of the patients after 1cm posterior shifts. Similarly, the heart V25 tolerance was exceeded after 1cm antero-posterior and left-right isocentric shifts in 70% of the patients. The baseline NTCPs for radiation-induced pneumonitis ranged from 0.73% - 3.4% with a mean value of 1.7%. The maximum reported NTCP for radiation-induced pneumonitis was 5.8% (mean 2.6%) after 1cm posterior isocentric shift. The NTCP for excess cardiac mortality were 0 % in 100% of the patients (n=12) before and after setup error simulations. Conclusions Set-up errors in left sided breast cancer patients have a statistically significant impact on the Lung NTCPs and DVH indices. However, with a central lung distance of 3cm or less (CLD <3cm), and a maximum heart distance of 1.5cm or less (MHD<1.5cm), the treatment plans could tolerate set-up errors of up to 1cm without any change in the NTCP to the heart.

CBCT image guidance in head and neck irradiation: The impact of daily and weekly imaging protocols

Purpose This study evaluated the impact of a daily and weekly image-guided radiotherapy protocols in reducing setup errors and setting of appropriate margins in head and neck cancer patients. Materials and methods Interfraction and systematic shifts for the hypothetical day 1–3 plus weekly imaging were extrapolated from daily imaging data from 31 patients (964 cone beam computed tomography (CBCT) scans). In addition, residual setup errors were calculated by taking the average shifts in each direction for each patient based on the first three shifts and were presumed to represent systematic setup error. The clinical target volume (CTV) to planning target volume (PTV) margins were calculated using van Herk formula and analysed for each protocol. Results The mean interfraction shifts for daily imaging were 0·8, 0·3 and 0·5 mm in the S-I (superior-inferior), L-R (left-right) and A-P (anterior-posterior) direction, respectively. On the other hand the mean shifts for day 1–3 plus weekly imaging were 0·9, 1·8 and 0·5 mm in the S-I, L-R and A-P direction, respectively. The mean day 1–3 residual shifts were 1·5, 2·1 and 0·7 mm in the S-I, L-R and A-P direction, respectively. No significant difference was found in the mean setup error for the daily and hypothetical day 1–3 plus weekly protocol. However, the calculated CTV to PTV margins for the daily interfraction imaging data were 1·6, 3·8 and 1·4 mm in the S-I, L-R and A-P directions, respectively. Hypothetical day 1–3 plus weekly resulted in CTV–PTV margins of 5, 4·2 and 5 mm in the S-I, L-R and A-P direction. Conclusions The results of this study show that a daily CBCT protocol reduces setup errors and allows setup margin reduction in head and neck radiotherapy compared to a weekly imaging protocol.

Of old and new. Messages conveyed by Australian Universities

On arriving at the University of Queensland, I walked from where the taxi dropped me off towards the Great Court. As I walked I could see the carvings in the sandstone on the façade of the building in front of me. The carvings depict images of land, flora, fauna, settlers, and us. In the corner of my right sight of vision, I could see Mayne Hall. My mind flicked back in what was an instant to a time 30 plus years ago. I remember putting on some of my best clothes when my family would travel form the suburb of Inala to the Alumni book fair held in the Hall. We needed to act ‘discrete’ and like we were ‘meant to be there’. Members of my family would work hard to save money to buy the books that had far more substance than the books at our local community or school library. This was my first interaction with the University of Queensland. On the first day of Courting Blakness, I walked towards and then into the Great Court. I began to explore and engage with the artworks and allow them to engage with me. I was conscious of being in the University of Queensland as I had been on all my past visits. I was conscious of the public and the private aspects of the artworks along with the public observance and surveillance of the viewers of the artworks. The contradictions and struggles that Aboriginal and Torres Strait Islander people experience are everywhere when moving in spaces and places, including universities. They contain prevailing social, political and economic values in the same way that other places do. The symbols of place and space within universities are never neutral, and they can work to either marginalise and oppress Aboriginal and Torres Strait Islander people, or demonstrate that they are included and engaged. The artworks in the Great Court were involved in this matrix of mixed messages and the weaves of time contained the borders of the Court and within the minds of those present.

Implementing music therapy on an adolescent inpatient unit: A mixed-methods evaluation of acceptability, experience of participation and perceived impact

Objective: We aimed to assess the feasibility of delivering a music therapy program on adolescent psychiatric wards. Method: We undertook a mixed-methods evaluation of a pilot program. Various active and receptive techniques were employed in group music therapy sessions delivered as part of a structured clinical program. Data collected in interviews with participants and staff and feedback questionnaires were thematically and descriptively analysed and triangulated. Results: Data from 62 questionnaires returned by 43 patients who took part in 16 music therapy sessions, and seven staff, evidenced strong support for music therapy. Patients typically reported experiencing sessions as relaxing, comforting, uplifting, and empowering; >90% would participate by choice and use music therapeutically in the future. Staff endorsed music therapy as valuable therapeutically, reporting that patients engaged enthusiastically and identified sessions as improving their own moods and ward milieu. Conclusions: Integration of music therapy in inpatient treatment of adolescents is feasible and acceptable, and is valued by staff and patients as a complement to ‘talking therapies’. Participation is enjoyed and associated with outcomes including improvement in mood, expression of feelings and social engagement consistent with recovery.