Lifestyle modification interventions for adults with intellectual disabilities: systematic review and meta-analysis at intervention and component levels

BACKGROUND

Adults with intellectual disabilities (IDs) are susceptible to multiple health risk behaviours such as alcohol consumption, smoking, low physical activity, sedentary behaviour and poor diet. Lifestyle modification interventions can prevent or reduce negative health consequences caused by these behaviours. We aim to determine the effectiveness of lifestyle modification interventions and their components in targeting health risk behaviours in adults with IDs.

METHODS

A systematic review and meta-analysis were conducted. Electronic databases, clinical trial registries, grey literature and citations of systematic reviews and included studies were searched in January 2021 (updated February 2022). Randomised controlled trials and non-randomised controlled trials targeting alcohol consumption, smoking, low physical activity, sedentary behaviours and poor diet in adults (aged ≥ 18 years) with ID were included. Meta-analysis was conducted at the intervention level (pairwise and network meta-analysis) and the component-level (component network meta-analysis). Studies were coded using Michie's 19-item theory coding scheme and 94-item behaviour change taxonomies. Risk of bias was assessed using the Cochrane Risk of Bias (ROB) Version 2 and Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I). The study involved a patient and public involvement (PPI) group, including people with lived experience, who contributed extensively by shaping the methodology, providing valuable insights in interpreting results and organising of dissemination events.

RESULTS

Our literature search identified 12 180 articles, of which 80 studies with 4805 participants were included in the review. The complexity of lifestyle modification intervention was dismantled by identifying six core components that influenced outcomes. Interventions targeting single or multiple health risk behaviours could have a single or combination of multiple core-components. Interventions (2 RCTS; 4 non-RCTs; 228 participants) targeting alcohol consumption and smoking behaviour were effective but based on limited evidence. Similarly, interventions targeting low physical activity only (16 RCTs; 17 non-RCTs; 1413 participants) or multiple behaviours (low physical activity only, sedentary behaviours and poor diet) (17 RCTs; 24 non-RCTs; 3164 participants) yielded mixed effectiveness in outcomes. Most interventions targeting low physical activity only or multiple behaviours generated positive effects on various outcomes while some interventions led to no change or worsened outcomes, which could be attributed to the presence of a single core-component or a combination of similar core components in interventions. The intervention-level meta-analysis for weight management outcomes showed that none of the interventions were associated with a statistically significant change in outcomes when compared with treatment-as-usual and each other. Interventions with core-components combination of energy deficit diet, aerobic exercise and behaviour change techniques showed the highest weight loss [mean difference (MD) = -3.61, 95% credible interval (CrI) -9.68 to 1.95] and those with core-components combination dietary advice and aerobic exercise showed a weight gain (MD 0.94, 95% CrI -3.93 to 4.91). Similar findings were found with the component network meta-analysis for which additional components were identified. Most studies had a high and moderate risk of bias. Various theories and behaviour change techniques were used in intervention development and adaptation.

CONCLUSION

Our systematic review is the first to comprehensively explore lifestyle modification interventions targeting a range of single and multiple health risk behaviours in adults with ID, co-produced with people with lived experience. It has practical implications for future research as it highlights the importance of mixed-methods research in understanding lifestyle modification interventions and the need for population-specific improvements in the field (e.g., tailored interventions, development of evaluation instruments or tools, use of rigorous research methodologies and comprehensive reporting frameworks). Wide dissemination of related knowledge and the involvement of PPI groups, including people with lived experience, will help future researchers design interventions that consider the unique needs, desires and abilities of people with ID.

Injectable nanocomposite hydrogels with enhanced lubrication and antioxidant properties for the treatment of osteoarthritis

Osteoarthritis (OA) is a chronic inflammatory joint disease characterized by progressive cartilage degeneration, synovitis, and osteoid formation. In order to effectively treat OA, it is important to block the harmful feedback caused by reactive oxygen species (ROS) produced during joint wear. To address this challenge, we have developed injectable nanocomposite hydrogels composed of polygallate-Mn (PGA-Mn) nanoparticles, oxidized sodium alginate, and gelatin. The inclusion of PGA-Mn not only enhances the mechanical strength of the biohydrogel through a Schiff base reaction with gelatin but also ensures efficient ROS scavenging ability. Importantly, the nanocomposite hydrogel exhibits excellent biocompatibility, allowing it to effectively remove ROS from chondrocytes and reduce the expression of inflammatory factors within the joint. Additionally, the hygroscopic properties of the hydrogel contribute to reduced intra-articular friction and promote the production of cartilage-related proteins, supporting cartilage synthesis. In vivo experiments involving the injection of nanocomposite hydrogels into rat knee joints with an OA model have demonstrated successful reduction of osteophyte formation and protection of cartilage from wear, highlighting the therapeutic potential of this approach for treating OA.

Supporting active engagement of adults with intellectual disabilities in lifestyle modification interventions: a realist evidence synthesis of what works, for whom, in what context and why

BACKGROUND

Lifestyle modification interventions for adults with intellectual disabilities have had, to date, mixed effectiveness. This study aimed to understand how lifestyle modification interventions for adults with intellectual disabilities work, for whom they work and in what circumstances.

METHODS

A realist evidence synthesis was conducted that incorporated input from adults with intellectual disabilities and expert researchers. Following the development of an initial programme theory based on key literature and input from people with lived experience and academics working in this field, five major databases (MEDLINE, EMBASE, CINAHL, PsycINFO and ASSIA) and clinical trial repositories were systematically searched. Data from 79 studies were synthesised to develop context, mechanism and outcome configurations (CMOCs).

RESULTS

The contexts and mechanisms identified related to the ability of adults with intellectual disabilities to actively take part in the intervention, which in turn contributes to what works, for whom and in what circumstances. The included CMOCs related to support involvement, negotiating the balance between autonomy and behaviour change, fostering social connectedness and fun, accessibility and suitability of intervention strategies and delivery and broader behavioural pathways to lifestyle change. It is also essential to work with people with lived experiences when developing and evaluating interventions.

CONCLUSIONS

Future lifestyle interventions research should be participatory in nature, and accessible data collection methods should also be explored as a way of including people with severe and profound intellectual disabilities in research. More emphasis should be given to the broader benefits of lifestyle change, such as opportunities for social interaction and connectedness.

Enhanced Mitochondrial Targeting and Inhibition of Pyroptosis with Multifunctional Metallopolyphenol Nanoparticles in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a significant contributor to low back pain, characterized by excessive reactive oxygen species generation and inflammation-induced pyroptosis. Unfortunately, there are currently no specific molecules or materials available to effectively delay IVDD. This study develops a multifunctional full name of PG@Cu nanoparticle network (PG@Cu). A designed pentapeptide, bonded on PG@Cu nanoparticles via a Schiff base bond, imparts multifunctionality to the metal polyphenol particles (PG@Cu-FP). PG@Cu-FP exhibits enhanced escape from lysosomal capture, enabling efficient targeting of mitochondria to scavenge excess reactive oxygen species. The scavenging activity against reactive oxygen species originates from the polyphenol-based structures within the nanoparticles. Furthermore, Pyroptosis is effectively blocked by inhibiting Gasdermin mediated pore formation and membrane rupture. PG@Cu-FP successfully reduces the activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome by inhibiting Gasdermin protein family (Gasdermin D, GSDMD) oligomerization, leading to reduced expression of Nod-like receptors. This multifaceted approach demonstrates higher efficiency in inhibiting Pyroptosis. Experimental results confirm that PG@Cu-FP preserves disc height, retains water content, and preserves tissue structure. These findings highlight the potential of PG@Cu-FP in improving IVDD and provide novel insights for future research in IVDD treatments.

Ethical Considerations and Fairness in the Use of Artificial Intelligence for Neuroradiology

In this review, concepts of algorithmic bias and fairness are defined qualitatively and mathematically. Illustrative examples are given of what can go wrong when unintended bias or unfairness in algorithmic development occurs. The importance of explainability, accountability, and transparency with respect to artificial intelligence algorithm development and clinical deployment is discussed. These are grounded in the concept of "primum no nocere" (first, do no harm). Steps to mitigate unfairness and bias in task definition, data collection, model definition, training, testing, deployment, and feedback are provided. Discussions on the implementation of fairness criteria that maximize benefit and minimize unfairness and harm to neuroradiology patients will be provided, including suggestions for neuroradiologists to consider as artificial intelligence algorithms gain acceptance into neuroradiology practice and become incorporated into routine clinical workflow.

Migraine-Associated Common Genetic Variants Confer Greater Risk of Posterior vs. Anterior Circulation Ischemic Stroke☆

OBJECTIVE

To examine potential genetic relationships between migraine and the two distinct phenotypes posterior circulation ischemic stroke (PCiS) and anterior circulation ischemic stroke (ACiS), we generated migraine polygenic risk scores (PRSs) and compared these between PCiS and ACiS, and separately vs. non-stroke control subjects.

METHODS

Acute ischemic stroke cases were classified as PCiS or ACiS based on lesion location on diffusion-weighted MRI. Exclusion criteria were lesions in both vascular territories or uncertain territory; supratentorial PCiS with ipsilateral fetal posterior cerebral artery; and cases with atrial fibrillation. We generated migraine PRS for three migraine phenotypes (any migraine; migraine without aura; migraine with aura) using publicly available GWAS data and compared mean PRSs separately for PCiS and ACiS vs. non-stroke control subjects, and between each stroke phenotype.

RESULTS

Our primary analyses included 464 PCiS and 1079 ACiS patients with genetic European ancestry. Compared to non-stroke control subjects (n=15396), PRSs of any migraine were associated with increased risk of PCiS (p=0.01-0.03) and decreased risk of ACiS (p=0.010-0.039). Migraine without aura PRSs were significantly associated with PCiS (p=0.008-0.028), but not with ACiS. When comparing PCiS vs. ACiS directly, migraine PRSs were higher in PCiS vs. ACiS for any migraine (p=0.001-0.010) and migraine without aura (p=0.032-0.048). Migraine with aura PRS did not show a differential association in our analyses.

CONCLUSIONS

Our results suggest a stronger genetic overlap between unspecified migraine and migraine without aura with PCiS compared to ACiS. Possible shared mechanisms include dysregulation of cerebral vessel endothelial function.

POS0530 HOW DOES MULTIMORBIDITY IMPACT ON THE DIRECT AND INDIRECT COSTS IN PATIENTS WITH RHEUMATOID ARTHRITIS?

Background:

Comorbidities are prevalent in patients with rheumatoid arthritis (RA) and associated with worse outcomes as well as higher economic burden. Little is known about the impact of multimorbidity on the direct and indirect costs of RA. Evidence of the incremental scale of these multimorbidity costs will usefully inform RA interventions and policies.

Objectives:

The aim of this study was to describe how multimorbidity impacts on the cost-of-illness, including direct and indirect costs, in patients with RA.

Methods:

The Scottish Early Rheumatoid Arthritis (SERA) is a registry of patients newly presenting with RA since 2011. It contains data on patient characteristics, clinical outcomes, health-related quality of life, and employment status data. These data were linked to routinely recorded hospital admissions and primary care prescribing data. Direct costs were estimated by applying relevant unit costs to healthcare resource use quantities. Indirect cost estimates were obtained from information on employment status and hospital admissions, valued by age and sex specific wages. Two-part models (probit followed by generalized linear model) were used to estimate direct and indirect costs, adjusting for age, gender, and functional disability. The Charlson Comorbidity Index (CCI) score was calculated using patient ICD-10 diagnoses from hospital records. The number of comorbidities was categorized into “RA alone”, “single comorbidity” and “multimorbidity (>1 comorbidity)”.

Results:

Data were available for 1,150 patients, 65.7% were female and a mean age of 57.5±14 years. The majority of patients only had RA (54.1%), followed by a single comorbidity (23.4%) and multimorbidity (22.5%). Annual total costs were significantly higher for patients with multimorbidity (£6,669 95% CI £4,871-£8,466; OR 11.3 95% CI 8.14-15.87) and for patients with a single comorbidity (£2,075 95% CI £1,559-£2,591; OR 3.52 95% CI 2.61-4.79), when compared with RA alone (£590). The excess costs were mainly driven by direct costs (£6,281 versus £1,875 versus £556). Although the difference in indirect costs between patients with multimorbidity and a single comorbidity were not statistically significant (£1,218 versus £914, p=0.11), patients with multimorbidity were associated with significantly higher costs than those with RA only (£594, p<0.01).

Conclusion:

The presence of comorbidity contributes significant excess to both direct and indirect costs among RA patients. In particular, patients with multimorbidity incurred substantially higher direct costs than those with a single comorbidity or RA only.

Acknowledgements:

The study analysed the data from the Scottish Early Rheumatoid Arthritis (SERA) study with a linkage to routinely recorded health data from Information Service Division, National Service Scotland. We would like to thank all the patients, clinical and nursing colleagues who have contributed their time and support to the study, the SERA steering committee for the approval, and Allen Tervit from the Robertson Centre for Biostatistics, University of Glasgow for the timely technical supports.

Disclosure of Interests:

Ping-Hsuan Hsieh: None declared, Claudia Geue: None declared, Olivia Wu Consultant of: OW has received consultancy fees from Bayer, Lupin and Takeda outside the submitted work., Emma McIntosh: None declared

Uterine artery embolisation or myomectomy for women with uterine fibroids wishing to avoid hysterectomy: a cost-utility analysis of the FEMME trial

OBJECTIVES

To assess the cost-effectiveness of uterine artery embolisation (UAE) and myomectomy for women with symptomatic uterine fibroids wishing to avoid hysterectomy.

DESIGN

Economic evaluation alongside the FEMME randomised controlled trial.

SETTING

29 UK hospitals.

POPULATION

Premenopausal women who had symptomatic uterine fibroids amenable to UAE or myomectomy wishing to avoid hysterectomy. 254 women were randomised to UAE (127) and myomectomy (127).

METHODS

A within-trial cost-utility analysis was conducted from the perspective of the UK NHS.

MAIN OUTCOME MEASURES

Quality-adjusted life years (QALYs) measured using the EuroQoL EQ-5D-3L, combined with costs to estimate cost-effectiveness over 2 and 4 years of follow-up.

RESULTS

Over a 2-year time horizon, UAE was associated with higher mean costs (difference £645; 95% CI -1381 to 2580) and lower QALYs (difference -0.09; 95% CI -0.11 to -0.04) when compared with myomectomy. Similar results were observed over the 4-year time horizon. Thus, UAE was dominated by myomectomy. Results of the sensitivity analyses were consistent with the base case results for both years. Over 2 years, UAE was associated with higher costs (difference £456; 95% CI -1823 to 3164) and lower QALYs (difference -0.06; 95% CI -0.11 to -0.02).

CONCLUSIONS

Myomectomy is a cost-effective option for the treatment of uterine fibroids. The differences in costs and QALYs are small. Women should be fully informed and have the option to choose between the two procedures.

The cost of prevalent and incident cardiovascular disease in people with type 2 diabetes in Scotland: data from the Scottish Care Information-Diabetes Collaboration

AIM

To compare costs for three groups of people with type 2 diabetes, those at high risk of future cardiovascular disease, those without cardiovascular disease and those with established cardiovascular disease, and to also compare costs incurred by people with type 2 diabetes with an incident cardiovascular disease event with those who remain incident event-free over a 3-year period.

METHODS

Data about people with type 2 diabetes in Scotland were obtained from the Scottish Care Information Diabetes registry. Data linkage was used to retrieve information on healthcare utilization, care home use and deaths. Productivity effects were estimated for those of non-pensionable age. We estimated costs over 12 months (prevalent cardiovascular disease) and 3 years from incident cardiovascular disease event.

RESULTS

Mean annual cost per person with established cardiovascular disease was £6900, £3300 for a person at high risk of future cardiovascular disease, and £2500 for a person without cardiovascular disease and not at high risk. In year 1, the cost of an incident cardiovascular disease event was £16 700 compared with £2100 for people without an incident event. Over 2 years, the cumulative costs were £21 500 and £4200, and by year 3, £25 000 and £5900, respectively.

CONCLUSIONS

Cardiovascular disease in people with type 2 diabetes places a significant financial burden on healthcare and the wider economy. Our results emphasize the financial consequences of cardiovascular disease prevention strategies.

Detailed phenotyping of posterior vs. anterior circulation ischemic stroke: a multi-center MRI study

OBJECTIVE

Posterior circulation ischemic stroke (PCiS) constitutes 20-30% of ischemic stroke cases. Detailed information about differences between PCiS and anterior circulation ischemic stroke (ACiS) remains scarce. Such information might guide clinical decision making and prevention strategies. We studied risk factors and ischemic stroke subtypes in PCiS vs. ACiS and lesion location on magnetic resonance imaging (MRI) in PCiS.

METHODS

Out of 3,301 MRIs from 12 sites in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Genetics Network (SiGN), we included 2,381 cases with acute DWI lesions. The definition of ACiS or PCiS was based on lesion location. We compared the groups using Chi-squared and logistic regression.

RESULTS

PCiS occurred in 718 (30%) patients and ACiS in 1663 (70%). Diabetes and male sex were more common in PCiS vs. ACiS (diabetes 27% vs. 23%, p < 0.05; male sex 68% vs. 58%, p < 0.001). Both were independently associated with PCiS (diabetes, OR = 1.29; 95% CI 1.04-1.61; male sex, OR = 1.46; 95% CI 1.21-1.78). ACiS more commonly had large artery atherosclerosis (25% vs. 20%, p < 0.01) and cardioembolic mechanisms (17% vs. 11%, p < 0.001) compared to PCiS. Small artery occlusion was more common in PCiS vs. ACiS (20% vs. 14%, p < 0.001). Small artery occlusion accounted for 47% of solitary brainstem infarctions.

CONCLUSION

Ischemic stroke subtypes differ between the two phenotypes. Diabetes and male sex have a stronger association with PCiS than ACiS. Definitive MRI-based PCiS diagnosis aids etiological investigation and contributes additional insights into specific risk factors and mechanisms of injury in PCiS.

Ensemble of Convolutional Neural Networks Improves Automated Segmentation of Acute Ischemic Lesions Using Multiparametric Diffusion-Weighted MRI

BACKGROUND AND PURPOSE

Accurate automated infarct segmentation is needed for acute ischemic stroke studies relying on infarct volumes as an imaging phenotype or biomarker that require large numbers of subjects. This study investigated whether an ensemble of convolutional neural networks trained on multiparametric DWI maps outperforms single networks trained on solo DWI parametric maps.

MATERIALS AND METHODS

Convolutional neural networks were trained on combinations of DWI, ADC, and low b-value-weighted images from 116 subjects. The performances of the networks (measured by the Dice score, sensitivity, and precision) were compared with one another and with ensembles of 5 networks. To assess the generalizability of the approach, we applied the best-performing model to an independent Evaluation Cohort of 151 subjects. Agreement between manual and automated segmentations for identifying patients with large lesion volumes was calculated across multiple thresholds (21, 31, 51, and 70 cm³).

RESULTS

An ensemble of convolutional neural networks trained on DWI, ADC, and low b-value-weighted images produced the most accurate acute infarct segmentation over individual networks (P < .001). Automated volumes correlated with manually measured volumes (Spearman ρ = 0.91, P < .001) for the independent cohort. For the task of identifying patients with large lesion volumes, agreement between manual outlines and automated outlines was high (Cohen κ, 0.86-0.90; P < .001).

CONCLUSIONS

Acute infarcts are more accurately segmented using ensembles of convolutional neural networks trained with multiparametric maps than by using a single model trained with a solo map. Automated lesion segmentation has high agreement with manual techniques for identifying patients with large lesion volumes.

Validity of the activPAL3 activity monitor in people moderately affected by Multiple Sclerosis

Walking is the primary form of physical activity performed by people with Multiple Sclerosis (MS), therefore it is important to ensure the validity of tools employed to measure walking activity. The aim of this study was to assess the criterion validity of the activPAL3 activity monitor during overground walking in people with MS. Validity of the activPAL3 accelerometer was compared to video observation in 20 people moderately affected by MS. Participants walked 20-30m twice along a straight quiet corridor at a comfortable speed. Inter-rater reliability of video observations was excellent (all intraclass correlations >0.99). The mean difference (activPAL3- mean of raters) was -4.70±9.09, -4.55s±10.76 and 1.11s±1.11 for steps taken, walking duration and upright duration respectively. These differences represented 8.7%, 10.0% and 1.8% of the mean for each measure respectively. The activPAL3 tended to underestimate steps taken and walking duration in those who walked at cadences of ≤38 steps/min by 60% and 47%, respectively. The activPAL3 is valid for measuring walking activity in people moderately affected by MS. It is accurate for upright duration regardless of cadence. In participants with slow walking cadences, outcomes of steps taken and walking duration should be interpreted with caution.

Combining MRI with NIHSS thresholds to predict outcome in acute ischemic stroke: value for patient selection

BACKGROUND AND PURPOSE

Selecting acute ischemic stroke patients for reperfusion therapy on the basis of a diffusion-perfusion mismatch has not been uniformly proved to predict a beneficial treatment response. In a prior study, we have shown that combining clinical with MR imaging thresholds can predict clinical outcome with high positive predictive value. In this study, we sought to validate this predictive model in a larger patient cohort and evaluate the effects of reperfusion therapy and stroke side.

MATERIALS AND METHODS

One hundred twenty-three consecutive patients with anterior circulation acute ischemic stroke underwent MR imaging within 6 hours of stroke onset. DWI and PWI volumes were measured. Lesion volume and NIHSS score thresholds were used in models predicting good 3-month clinical outcome (mRS 0-2). Patients were stratified by treatment and stroke side.

RESULTS

Receiver operating characteristic analysis demonstrated 95.6% and 100% specificity for DWI > 70 mL and NIHSS score > 20 to predict poor outcome, and 92.7% and 91.3% specificity for PWI (mean transit time) < 50 mL and NIHSS score < 8 to predict good outcome. Combining clinical and imaging thresholds led to an 88.8% (71/80) positive predictive value with a 65.0% (80/123) prognostic yield. One hundred percent specific thresholds for DWI (103 versus 31 mL) and NIHSS score (20 versus 17) to predict poor outcome were significantly higher in treated (intravenous and/or intra-arterial) versus untreated patients. Prognostic yield was lower in right- versus left-sided strokes for all thresholds (10.4%-20.7% versus 16.9%-40.0%). Patients with right-sided strokes had higher 100% specific DWI (103.1 versus 74.8 mL) thresholds for poor outcome, and the positive predictive value was lower.

CONCLUSIONS

Our predictive model is validated in a much larger patient cohort. Outcome may be predicted in up to two-thirds of patients, and thresholds are affected by stroke side and reperfusion therapy.

EEG functional connectivity is partially predicted by underlying white matter connectivity

Over the past decade, networks have become a leading model to illustrate both the anatomical relationships (structural networks) and the coupling of dynamic physiology (functional networks) linking separate brain regions. The relationship between these two levels of description remains incompletely understood and an area of intense research interest. In particular, it is unclear how cortical currents relate to underlying brain structural architecture. In addition, although theory suggests that brain communication is highly frequency dependent, how structural connections influence overlying functional connectivity in different frequency bands has not been previously explored. Here we relate functional networks inferred from statistical associations between source imaging of EEG activity and underlying cortico-cortical structural brain connectivity determined by probabilistic white matter tractography. We evaluate spontaneous fluctuating cortical brain activity over a long time scale (minutes) and relate inferred functional networks to underlying structural connectivity for broadband signals, as well as in seven distinct frequency bands. We find that cortical networks derived from source EEG estimates partially reflect both direct and indirect underlying white matter connectivity in all frequency bands evaluated. In addition, we find that when structural support is absent, functional connectivity is significantly reduced for high frequency bands compared to low frequency bands. The association between cortical currents and underlying white matter connectivity highlights the obligatory interdependence of functional and structural networks in the human brain. The increased dependence on structural support for the coupling of higher frequency brain rhythms provides new evidence for how underlying anatomy directly shapes emergent brain dynamics at fast time scales.

Exposing hidden truncation-related errors in acute stroke perfusion imaging

BACKGROUND AND PURPOSE

The durations of acute ischemic stroke patients' CT or MR perfusion scans may be too short to fully sample the passage of the injected contrast agent through the brain. We tested the potential magnitude of hidden errors related to the truncation of data by short perfusion scans.

MATERIALS AND METHODS

Fifty-seven patients with acute ischemic stroke underwent perfusion MR imaging within 12 hours of symptom onset, using a relatively long scan duration (110 seconds). Shorter scan durations (39.5-108.5 seconds) were simulated by progressively deleting the last-acquired images. CBV, CBF, MTT, and time to response function maximum (Tmax) were measured within DWI-identified acute infarcts, with commonly used postprocessing algorithms. All measurements except Tmax were normalized by dividing by the contralateral hemisphere values. The effects of the scan duration on these hemodynamic measurements and on the volumes of lesions with Tmax of >6 seconds were tested using regression.

RESULTS

Decreasing scan duration from 110 seconds to 40 seconds falsely reduced perfusion estimates by 47.6%-64.2% of normal for CBV, 1.96%-4.10% for CBF, 133%-205% for MTT, and 6.2-8.0 seconds for Tmax, depending on the postprocessing method. This truncation falsely reduced estimated Tmax lesion volume by 71.5 or 93.8 mL, depending on the deconvolution method. "Lesion reversal" (ie, change from above-normal to apparently normal, or from >6 seconds to ≤6 seconds for the time to response function maximum) with increasing truncation occurred in 37%-46% of lesions for CBV, 2%-4% for CBF, 28%-54% for MTT, and 42%-44% for Tmax, depending on the postprocessing method.

CONCLUSIONS

Hidden truncation-related errors in perfusion images may be large enough to alter patient management or affect outcomes of clinical trials.

The effect of deprivation and HbA1c on admission to hospital for diabetic ketoacidosis in type 1 diabetes

AIMS/HYPOTHESIS

Diabetic ketoacidosis is a potentially life-threatening complication of diabetes and has a strong relationship with HbA(1c). We examined how socioeconomic group affects the likelihood of admission to hospital for diabetic ketoacidosis.

METHODS

The Scottish Care Information - Diabetes Collaboration (SCI-DC), a dynamic national register of all cases of diagnosed diabetes in Scotland, was linked to national data on hospital admissions. We identified 24,750 people with type 1 diabetes between January 2005 and December 2007. We assessed the relationship between HbA(1c) and quintiles of deprivation with hospital admissions for diabetic ketoacidosis in people with type 1 diabetes adjusting for patient characteristics.

RESULTS

We identified 23,479 people with type 1 diabetes who had complete recording of covariates. Deprivation had a substantial effect on odds of admission to hospital for diabetic ketoacidosis (OR 4.51, 95% CI 3.73, 5.46 in the most deprived quintile compared with the least deprived). This effect persisted after the inclusion of HbA(1c) and other risk factors (OR 2.81, 95% CI 2.32, 3.39). Men had a reduced risk of admission to hospital for diabetic ketoacidosis (OR 0.71, 95% CI 0.63, 0.79) and those with a history of smoking had increased odds of admission to hospital for diabetic ketoacidosis by a factor of 1.55 (95% CI 1.36, 1.78).

CONCLUSIONS/INTERPRETATION

Women, smokers, those with high HbA(1c) and those living in more deprived areas have an increased risk of admission to hospital for diabetic ketoacidosis. The effect of deprivation was present even after inclusion of other risk factors. This work highlights that those in poorer areas of the community with high HbA(1c) represent a group who might be usefully supported to try to reduce hospital admissions.

Developing and validating a predictive model for stroke progression

BACKGROUND

Progression is believed to be a common and important complication in acute stroke, and has been associated with increased mortality and morbidity. Reliable identification of predictors of early neurological deterioration could potentially benefit routine clinical care. The aim of this study was to identify predictors of early stroke progression using two independent patient cohorts.

METHODS

Two patient cohorts were used for this study - the first cohort formed the training data set, which included consecutive patients admitted to an urban teaching hospital between 2000 and 2002, and the second cohort formed the test data set, which included patients admitted to the same hospital between 2003 and 2004. A standard definition of stroke progression was used. The first cohort (n = 863) was used to develop the model. Variables that were statistically significant (p < 0.1) on univariate analysis were included in the multivariate model. Logistic regression was the technique employed using backward stepwise regression to drop the least significant variables (p > 0.1) in turn. The second cohort (n = 216) was used to test the performance of the model. The performance of the predictive model was assessed in terms of both calibration and discrimination. Multiple imputation methods were used for dealing with the missing values.

RESULTS

Variables shown to be significant predictors of stroke progression were conscious level, history of coronary heart disease, presence of hyperosmolarity, CT lesion, living alone on admission, Oxfordshire Community Stroke Project classification, presence of pyrexia and smoking status. The model appears to have reasonable discriminative properties [the median receiver-operating characteristic curve value was 0.72 (range 0.72-0.73)] and to fit well with the observed data, which is indicated by the high goodness-of-fit p value [the median p value from the Hosmer-Lemeshow test was 0.90 (range 0.50-0.92)].

CONCLUSION

The predictive model developed in this study contains variables that can be easily collected in practice therefore increasing its usability in clinical practice. Using this analysis approach, the discrimination and calibration of the predictive model appear sufficiently high to provide accurate predictions. This study also offers some discussion around the validation of predictive models for wider use in clinical practice.

Inpatient costs for people with type 1 and type 2 diabetes in Scotland: a study from the Scottish Diabetes Research Network Epidemiology Group

AIMS/HYPOTHESIS

The rising prevalence of diabetes worldwide has increased interest in the cost of diabetes. Inpatient costs for all people with diabetes in Scotland were investigated.

METHODS

The Scottish Care Information-Diabetes Collaboration (SCI-DC), a real-time clinical information system of almost all diagnosed cases of diabetes in Scotland, UK, was linked to data on all hospital admissions for people with diabetes. Inpatient stay costs were estimated using the 2007-2008 Scottish National Tariff. The probability of hospital admission and total annual cost of admissions were estimated in relation to age, sex, type of diabetes, history of vascular admission, HbA(1c), creatinine, body mass index and diabetes duration.

RESULTS

In Scotland during 2005-2007, 24,750 people with type 1 and 195,433 people with type 2 diabetes were identified, accounting for approximately 4.3% of the total Scottish population (5.1 million). The estimated total annual cost of admissions for all people diagnosed with type 1 and type 2 diabetes was £26 million and £275 million, respectively, approximately 12% of the total Scottish inpatient expenditure (£2.4 billion). Sex, increasing age, serum creatinine, previous vascular history and HbA(1c) (the latter differentially in type 1 and type 2) were all associated with likelihood and total annual cost of admission.

CONCLUSIONS/INTERPRETATION

Diabetes inpatient expenditure accounted for 12% of the total Scottish inpatient expenditure, whilst people with diabetes account for 4.3% of the population. Of the modifiable risk factors, HbA(1c) was the most important driver of cost in type 1 diabetes.

Serum soluble nucleosome and the broad family of antinucleosome antibodies are associated with organ and tissue damage in systemic lupus erythematosus in a Chinese population

Nucleosomes and the broad family of antinucleosome antibodies (ANAs; anti-double-stranded DNA, antihistone and antinucleosome antibodies) may contribute to the pathogenesis of systemic lupus erythematosus (SLE). We collected clinical information on 90 patients with SLE and 73 healthy volunteers and measured serum levels of the ANA family using a double-sandwich ELISA. The results showed that the levels of serum nucleosomes of patients with SLE was significantly lower and the levels of ANA were significantly higher than healthy controls. Negative correlations between serum nucleosomes and ANA, and positive correlations between individual ANAs were found. Patients with SLE with positive ANA had a significantly higher frequency of renal disorders than those with negative ANA. Determination of serum nucleosomes and ANAs contributes to SLE monitoring.

ABO(H) blood groups and vascular disease: a systematic review and meta-analysis

BACKGROUND

Associations between vascular disease and ABO(H) blood groups have a long history, but no consensus exists regarding its magnitude and significance, or whether it relates to all disorders equally. An accurate calculation of risk would allow direct assessment of whether the effects of non-O status on thrombosis risk are of the magnitude predicted by its effect on von Willebrand factor/FVIII levels.

METHODS AND RESULTS

We conducted a systematic review and meta-analysis of studies reporting associations with non-O blood groups. This gave pooled odds ratios of 1.25 [95% confidence interval (CI) 1.14-1.36] for myocardial infarction (MI), 1.03 (95% CI 0.89-1.19) for angina, 1.45 (95% CI 1.35-1.56) for peripheral vascular disease, 1.14 (95% CI 1.01-1.27) for cerebral ischemia of arterial origin, and 1.79 (95% CI 1.56 to 2.05) for venous thromboembolism (VTE). However, restriction to prospective MI studies only did not confirm the association (OR 1.01; 95% CI 0.84-1.23), although these studies may have failed to capture early-onset disease. For VTE, using a combined group of OO/A(2)A(2)/A(2)O as index, the combination of A(1)A(1)/A(1)B/BB gave an OR of 2.44 (95% CI 1.79-3.33) and A(1)O/ BO/A(2)B an OR of 2.11 (95% CI 1.66-2.68).

CONCLUSIONS

This study confirms the historical impression of linkage between some vascular disorders and non-O blood group status. Although the odds ratios are similar to those predicted by the effect of ABO(H) on von Willebrand factor levels, further work is required to assess risk prospectively and to refine the effect of reducing O(H) antigen expression on thrombosis. However, as non-O and particularly A(1)A(1), A(1)B, BB constitute a significant proportion of the population attributable fraction of VTE, there may be a role for more widespread adoption of ABO(H) typing in testing strategies.

Uterine artery embolisation or hysterectomy for the treatment of symptomatic uterine fibroids: a cost-utility analysis of the HOPEFUL study

OBJECTIVES

To evaluate the relative cost-effectiveness of uterine artery embolisation (UAE) and hysterectomy in women with symptomatic uterine fibroids from the perspective of the UK NHS.

DESIGN

Cost-utility analysis.

SETTING

Eighteen UK NHS hospital trusts. POPULATION OR SAMPLE Women who underwent UAE (n= 649; average follow up of 8.6 years) or hysterectomy (n= 459; average follow up of 4.6 years) for the treatments of symptomatic fibroids.

METHODS

A probabilistic decision model was carried out based on data from a large comparative cohort and the literature. The two interventions were evaluated over the time horizon from the initial procedure to menopause. Extensive sensitivity analysis was carried out to test model assumptions and parameter uncertainties.

MAIN OUTCOME MEASURES

Costs of procedures and complications and quality of life expressed as quality-adjusted life years (QALYs).

RESULTS

Overall, UAE was associated with lower mean cost (2536 pounds sterling versus 3282 pounds sterling) and a small reduction in quality of life (8.203 versus 8.241 QALYs) when compared with hysterectomy. However, when the quality of life associated with the conservation of the uterus was incorporated in the model, UAE was shown to be the dominant strategy--lower costs and greater QALYs.

CONCLUSIONS

UAE is a less expensive option to the health service compared with hysterectomy, even when the costs of repeat procedures and associated complications are factored in. The quality of life implications in the short term are also predicted to favour UAE; however, this advantage may be eroded over time as women undergo additional procedures to deal with recurrent fibroids. Given the hysterectomy is the current standard treatment for symptomatic fibroids, offering women UAE as an alternative treatment for fibroids is likely to be highly cost-effective for those women who prefer uterus-conserving treatment.

Screening for thrombophilia in high-risk situations: systematic review and cost-effectiveness analysis. The Thrombosis: Risk and Economic Assessment of Thrombophilia Screening (TREATS) study

OBJECTIVES

To assess the risk of clinical complications associated with thrombophilia in three high-risk patient groups: women using oral oestrogen preparations, women during pregnancy and patients undergoing major orthopaedic surgery. To assess the effectiveness of prophylactic treatments in preventing venous thromboembolism (VTE) and adverse pregnancy outcomes in women with thrombophilia during pregnancy and VTE in patients with thrombophilia, undergoing major orthopaedic surgery. To evaluate the relative cost-effectiveness of universal and selective VTE history-based screening for thrombophilia compared with no screening in the three high-risk patient groups.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, and four other major databases were searched up to June 2003.

REVIEW METHODS

In order to assess the risk of clinical complications associated with thrombophilia, a systematic review of the literature on VTE and thrombophilia in women using oral oestrogen preparations and patients undergoing major orthopaedic surgery; and studies of VTE and adverse obstetric complications in women with thrombophilia during pregnancy was carried out. Meta-analysis was used to calculate pooled odds ratios (ORs) associated with individual clinical outcomes, stratified by thrombophilia type and were calculated for each patient group. To assess the effectiveness of prophylaxis, a systematic review was carried out on the use of prophylaxis in the prevention of VTE and pregnancy loss in pregnant women with thrombophilic defects and the use of thromboprophylaxis in the prevention of VTE in patients with thrombophilia undergoing major elective orthopaedic surgery. Relevant data were summarised according to the patient groups and stratified according to the types of prophylaxis. A narrative summary was provided; where appropriate, meta-analysis was conducted. An incremental cost-effectiveness analysis was then carried out, from the perspective of the NHS in the UK. A decision analytical model was developed to simulate the clinical consequences of four thrombophilia screening scenarios. Results from the meta-analyses, information from the literature and results of two Delphi studies of clinical management of VTE and adverse pregnancy complications were incorporated into the model. Only direct health service costs were measured and unit costs for all healthcare resources used were obtained from routinely collected data and the literature. Cost-effectiveness was expressed as incremental cost-effectiveness ratios (ICERs); an estimate of the cost per adverse clinical complication prevented, comparing screening with no screening, were calculated for each patient group.

RESULTS

In the review of risk of clinical complications, 81 studies were included, nine for oral oestrogen preparations, 72 for pregnancy and eight for orthopaedic surgery. For oral contraceptive use, significant associations of the risk of VTE were found in women with factor V Leiden (FVL); deficiencies of antithrombin, protein C, or protein S, elevated levels of factor VIIIc; and FVL and prothrombin G20210A. For hormone replacement therapy (HRT), a significant association was found in women with FVL. The highest risk in pregnancy was found for FVL and VTE, in particular, homozygous carriers of this mutation are 34 times more likely to develop VTE in pregnancy than non-carriers. Significant risks for individual thrombophilic defects were also established for early, recurrent and late pregnancy loss; preeclampsia; placental abruption; and intrauterine growth restriction. Significant associations were found between FVL and high factor VIIIc and postoperative VTE following elective hip or knee replacement surgery. Prothrombin G20210A was significantly associated with postoperative pulmonary embolism. However, antithrombin deficiency, MTHFR and hyperhomocysteinaemia were not associated with increased risk of postoperative VTE. In the review of the effectiveness of prophylaxis, based on available data from eight studies, low-dose aspirin and heparin was found to be the most effective in preventing pregnancy loss in thrombophilic women during pregnancy, while aspirin alone was the most effective in preventing minor bleeding. All the studies on thrombophilia and major elective orthopaedic surgery included in the review of risk complications were also used in the review of the effectiveness of thromboprophylaxis. However, there were insufficient data to determine the relative effectiveness of different thromboprophylaxis in preventing VTE in this patient group. For the cost-effectiveness analysis, of all the patient groups evaluated, universal screening of women prior to prescribing HRT was the most cost-effective (ICER pound6824). In contrast, universal screening of women prior to prescribing combined oral contraceptives was the least cost-effective strategy (ICER pound202,402). Selective thrombophilia screening based on previous personal and/or family history of VTE was more cost-effective than universal screening in all the patient groups evaluated.

CONCLUSIONS

Thrombophilia is associated with increased risks of VTE in women taking oral oestrogen preparations and patients undergoing major elective orthopaedic surgery, and of VTE and adverse pregnancy outcomes in women with thrombophilia during pregnancy. There is considerable difference in the magnitude of the risks among different patient groups with different thrombophilic defects. In women who are on combined oral contraceptives, the OR of VTE among those who are carriers of the FVL mutation was 15.62 (95% confidence interval 8.66 to 28.15). However, in view of the prevalence of thrombophilia and the low prevalence of VTE in non-users of combined oral contraceptives, the absolute risk remains low. Significant risks for VTE and adverse pregnancy outcomes have been established with individual thrombophilic defects. Thrombophilic defects including FVL, high plasma factor VIIIc levels and prothrombin G20210A are associated with the occurrence of postoperative VTE in elective hip or knee replacement therapy. These associations are observed in patients who were given preoperative thromboprophylaxis and are, therefore, of clinical significance. Universal thrombophilia screening in women prior to prescribing oral oestrogen preparations, in women during pregnancy and in patients undergoing major orthopaedic surgery is not supported by current evidence. The findings from this study show that selective screening based on prior VTE history is more cost-effective than universal screening. Large prospective studies should be undertaken to refine the risks and establish the associations of thrombophilias with VTE among hormone users and in patients undergoing orthopaedic surgery. The relative value of a thrombophilia screening programme to other healthcare programmes needs to be established.

Thrombophilia in pregnancy: a systematic review

Growing evidence suggests that thrombophilia is associated with venous thromboembolism (VTE) and adverse pregnancy outcomes. However, methodological limitations have made it difficult to obtain a clear overview of the overall risks. We conducted a systematic review to determine the risk of VTE and adverse pregnancy outcomes associated with thrombophilia in pregnancy. The effectiveness of prophylactic interventions during pregnancy was also evaluated. Major electronic databases were searched, relevant data abstracted and study quality assessed by two independent reviewers. Odds ratios (ORs) stratified by thrombophilia type were calculated for each outcome. A total of 79 studies were included in our review. The risks for individual thrombophilic defects were determined for VTE (ORs, 0.74-34.40); early pregnancy loss (ORs, 1.40-6.25); late pregnancy loss (ORs, 1.31-20.09); pre-eclampsia (ORs, 1.37-3.49); placental abruption (ORs, 1.42-7.71) and intrauterine growth restriction (ORs, 1.24-2.92). Low-dose aspirin plus heparin was the most effective in preventing pregnancy loss in thrombophilic women (OR, 1.62). Our findings confirm that women with thrombophilia are at risk of developing VTE and complications in pregnancy. However, despite the increase in relative risk, the absolute risk of VTE and adverse outcomes remains low. There is also a lack of controlled trials of antithrombotic intervention to prevent pregnancy complications. Thus, at present, universal screening for thrombophilia in pregnancy cannot be justified clinically.

Functional magnetic resonance imaging of reorganization in rat brain after stroke

Functional recovery after stroke has been associated with brain plasticity; however, the exact relationship is unknown. We performed behavioral tests, functional MRI, and histology in a rat stroke model to assess the correlation between temporal changes in sensorimotor function, brain activation patterns, cerebral ischemic damage, and cerebrovascular reactivity. Unilateral stroke induced a large ipsilateral infarct and acute dysfunction of the contralateral forelimb, which significantly recovered at later stages. Forelimb impairment was accompanied by loss of stimulus-induced activation in the ipsilesional sensorimotor cortex; however, local tissue and perfusion were only moderately affected and cerebrovascular reactivity was preserved in this area. At 3 days after stroke, extensive activation-induced responses were detected in the contralesional hemisphere. After 14 days, we found reduced involvement of the contralesional hemisphere, and significant responses in the infarction periphery. Our data suggest that limb dysfunction is related to loss of brain activation in the ipsilesional sensorimotor cortex and that restoration of function is associated with biphasic recruitment of peri- and contralesional functional fields in the brain.

Ischemic stroke: effects of etiology and patient age on the time course of the core apparent diffusion coefficient

PURPOSE

To determine whether the evolution of the core apparent diffusion coefficient (ADC) of water in ischemic stroke varies with patient age or infarct etiology.

MATERIALS AND METHODS

One hundred forty-seven patients with stroke underwent 236 diffusion-weighted magnetic resonance imaging examinations. Etiologies of lesions were classified according to predefined criteria; in 224 images, the diagnosis of lacune could be firmly established or excluded. ADC was measured in the center of each lesion and in contralateral normal-appearing brain. A model was used to describe the time course of relative ADC (rADC), which is calculated by dividing the lesion ADC by the contralateral ADC, and to test for age- or etiology-related differences in this time course.

RESULTS

Transition from decreasing to increasing rADC was estimated at 18.5 hours after stroke onset. In subgroup analysis, transition was earlier in nonlacunes than in lacunes (P =.02). There was a trend toward earlier transition in patients older than the median age of 66.0 years, compared with younger patients (P =.06). Pseudonormalization was estimated at 216 hours. Among nonlacunes, the rate of subsequent rADC increase was more rapid in younger patients than in older patients (P =.001). Within the smaller sample of lacunes, however, no significant age-related difference in this rate was found.

CONCLUSION

Differences in ADC depending on the patient's age and infarct etiology suggest differing rates of ADC progression.

Frequency and clinical context of decreased apparent diffusion coefficient reversal in the human brain

PURPOSE

To determine the probability that regions of decreased apparent diffusion coefficient (ADC) return to normal without persistent symptoms or T2 change and the settings in which these ADC reversals occur.

MATERIALS AND METHODS

Three hundred magnetic resonance (MR) imaging studies were selected at random from a database of 7,147 examinations to determine the probability of a pathologically decreased ADC. In cases with decreased ADC, the clinical history was recorded and, if available, follow-up MR imaging findings were evaluated. Five cases of ADC reversal became known during the same period and were evaluated to determine the initial ADC decrease, clinical outcome, and findings at follow-up imaging.

RESULTS

Findings in 116 of 300 MR imaging studies revealed regions of decreased ADC. In 49 of 116 studies, follow-up MR imaging examinations were performed at least 4 weeks after the onset of symptoms; ADC did not reverse. Five cases of ADC reversal were identified in the same period, giving an estimated 0.2%-0.4% probability of ADC reversal. Clinical settings were venous sinus thrombosis and seizure (n = 3), hemiplegic migraine (n = 1), and hyperacute arterial infarction (n = 1). Both white matter (n = 3) and gray matter (n = 3) regions were involved.

CONCLUSION

Reversal of ADC lesions is rare, occurs in complicated clinical settings, and can involve white or gray matter.

Delayed rt-PA treatment in a rat embolic stroke model: diagnosis and prognosis of ischemic injury and hemorrhagic transformation with magnetic resonance imaging

The authors characterized effects of late recombinant tissue plasminogen activator (rt-PA) administration in a rat embolic stroke model with magnetic resonance imaging (MRI), to assess potential MRI correlates, or predictors, or both, of rt-PA-induced hemorrhage. Diffusion-, perfusion-, and postcontrast T1-weighted MRI were performed between 4 and 9 hours and at 24 hours after embolic stroke in spontaneously hypertensive rats. Treatment with either rt-PA or saline was started 6 hours after stroke. A spectrophotometric hemoglobin assay quantified hemorrhage severity. Before treatment, relative cerebral blood flow index (rCBFi) and apparent diffusion coefficient (ADC) in the ischemic territory were 30% +/- 23% and 60% +/- 5% (of contralateral), respectively, which increased to 45% +/- 39% and 68% +/- 4% 2 hours after rt-PA. After 24 hours, rCBFi and ADC were 27% +/- 27% and 59 +/- 5%. Hemorrhage volume after 24 hours was significantly greater in rt-PA-treated animals than in controls (8.7 +/- 3.7 microL vs. 5.1 +/- 2.4 microL, P < 0.05). Before rt-PA administration, clear postcontrast T1-weighted signal intensity enhancement was evident in areas of subsequent bleeding. These areas had lower rCBFi levels than regions without hemorrhage (23% +/- 22% vs. 36% +/- 29%, P < 0.05). In conclusion, late thrombolytic therapy does not necessarily lead to successful reperfusion. Hemorrhage emerged in areas with relatively low perfusion levels and early blood-brain barrier damage. Magnetic resonance imaging may be useful for quantifying effects of thrombolytic therapy and predicting risks of hemorrhagic transformation.

Highly diffusion-sensitized MRI of brain: dissociation of gray and white matter

The brains of six healthy volunteers were scanned with a full tensor diffusion MRI technique to study the effect of a high b value on diffusion-weighted images (DWIs). The b values ranged from 500 to 5000 s/mm(2). Isotropic DWIs, trace apparent diffusion coefficient (ADC) maps, and fractional anisotropy (FA) maps were created for each b value. As the b value increased, ADC decreased in both the gray and white matter. Furthermore, ADC of the white matter became lower than that of the gray matter, and, as a result, the white matter became brighter than the gray matter in the isotropic DWIs. Quantitative analysis showed that these changes were due to nonmonoexponential diffusion signal decay of the brain tissue, which was more prominent in white matter than in gray matter. There was no significant change in relation to the b value in the FA maps. High b value appears to have a dissociating effect on gray and white matter in DWIs.

Mechanisms of migraine aura revealed by functional MRI in human visual cortex

Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. However, it has been challenging to test this hypothesis in human cerebral cortex. Using high-field functional MRI with near-continuous recording during visual aura in three subjects, we observed blood oxygenation level-dependent (BOLD) signal changes that demonstrated at least eight characteristics of CSD, time-locked to percept/onset of the aura. Initially, a focal increase in BOLD signal (possibly reflecting vasodilation), developed within extrastriate cortex (area V3A). This BOLD change progressed contiguously and slowly (3.5 +/- 1.1 mm/min) over occipital cortex, congruent with the retinotopy of the visual percept. Following the same retinotopic progression, the BOLD signal then diminished (possibly reflecting vasoconstriction after the initial vasodilation), as did the BOLD response to visual activation. During periods with no visual stimulation, but while the subject was experiencing scintillations, BOLD signal followed the retinotopic progression of the visual percept. These data strongly suggest that an electrophysiological event such as CSD generates the aura in human visual cortex.

Predicting tissue outcome in acute human cerebral ischemia using combined diffusion- and perfusion-weighted MR imaging

BACKGROUND AND PURPOSE

Tissue signatures from acute MR imaging of the brain may be able to categorize physiological status and thereby assist clinical decision making. We designed and analyzed statistical algorithms to evaluate the risk of infarction for each voxel of tissue using acute human functional MRI.

METHODS

Diffusion-weighted MR images (DWI) and perfusion-weighted MR images (PWI) from acute stroke patients scanned within 12 hours of symptom onset were retrospectively studied and used to develop thresholding and generalized linear model (GLM) algorithms predicting tissue outcome as determined by follow-up MRI. The performances of the algorithms were evaluated for each patient by using receiver operating characteristic curves.

RESULTS

At their optimal operating points, thresholding algorithms combining DWI and PWI provided 66% sensitivity and 83% specificity, and GLM algorithms combining DWI and PWI predicted with 66% sensitivity and 84% specificity voxels that proceeded to infarct. Thresholding algorithms that combined DWI and PWI provided significant improvement to algorithms that utilized DWI alone (P=0.02) but no significant improvement over algorithms utilizing PWI alone (P=0.21). GLM algorithms that combined DWI and PWI showed significant improvement over algorithms that used only DWI (P=0.02) or PWI (P=0.04). The performances of thresholding and GLM algorithms were comparable (P>0.2).

CONCLUSIONS

Algorithms that combine acute DWI and PWI can assess the risk of infarction with higher specificity and sensitivity than algorithms that use DWI or PWI individually. Methods for quantitatively assessing the risk of infarction on a voxel-by-voxel basis show promise as techniques for investigating the natural spatial evolution of ischemic damage in humans.

Additive anti-emetic efficacy of prophylactic ondansetron with droperidol in out-patient gynecological laparoscopy

PURPOSE

To determine the efficacy of ondansetron and droperidol, alone and in combination, administered for prophylaxis of postoperative nausea and vomiting (PONV) in women undergoing general anesthesia for outpatient gynecological laparoscopy.

METHODS

Following Institutional Ethics Board approval and patient consent, 160 female out- patients scheduled for laparoscopy were randomly allotted in a double-blind fashion to receive: i) saline (placebo), ii) 4 mg ondansetron, iii) 1.25 mg droperidol, or iv) 4 mg ondansetron and 1.25 mg droperidol combination intravenously on induction. Following a standardized general anesthesia, patients were interviewed and assessed for PONV at various times.

RESULTS

During the first 24 hr after surgery, the incidence of PONV in the placebo group was 71%. This was reduced to 61% with droperidol alone (P = 0.334), to 46% with ondansetron alone (P = 0.027), and to 23% with the combination group (P<0.001). A statistically significant difference was observed between combination and droperidol (P<0.001) and between combination and ondansetron (P = 0.036). There were fewer requests for rescue medication from the combination group (7.7%) than from the ondansetron and placebo groups.

CONCLUSION

The results of this study suggest that the combination of 4 mg ondansetron and 1.25 mg droperidol is more efficacious as a prophylactic anti-emetic than either agent alone during the 24 hr post-surgery. This additive effect may be due to the different mechanisms of action of ondansetron and droperidol.

Combined diffusion-weighted and perfusion-weighted flow heterogeneity magnetic resonance imaging in acute stroke

BACKGROUND AND PURPOSE

The heterogeneity of microvascular flows is known to be an important determinant of the efficacy of oxygen delivery to tissue. Studies in animals have demonstrated decreased flow heterogeneity (FH) in states of decreased perfusion pressure. The purpose of the present study was to assess microvascular FH changes in acute stroke with use of a novel perfusion-weighted MRI technique and to evaluate the ability of combined diffusion-weighted MRI and FH measurements to predict final infarct size.

METHODS

Cerebral blood flow, FH, and plasma mean transit time (MTT) were measured in 11 patients who presented with acute (<12 hours after symptom onset) stroke. Final infarct size was determined with follow-up MRI or CT scanning.

RESULTS

In normal brain tissue, the distribution of relative flows was markedly skewed toward high capillary flow velocities. Within regions of decreased cerebral blood flow, plasma MTT was prolonged. Furthermore, subregions were identified with significant loss of the high-flow component of the flow distribution, thereby causing increased homogeneity of flow velocities. In parametric maps that quantify the acute deviation of FH from that of normal tissue, areas of extreme homogenization of capillary flows predicted final infarct size on follow-up scans of 10 of 11 patients.

CONCLUSIONS

Flow heterogeneity and MTT can be rapidly assessed as part of a routine clinical MR examination and may provide a tool for planning of individual stroke treatment, as well as in targeting and evaluation of emerging therapeutic strategies.

Perfusion weighted imaging during migraine: spontaneous visual aura and headache

Using perfusion weighted imaging, we studied 28 spontaneous migraine episodes; 7 during visual aura (n = 6), 7 during the headache phase following visual aura (n = 3), and 14 cases of migraine without aura (n = 13). The data were analyzed using a region-of-interest-based approach. During aura, relative cerebral blood flow (rCBF) was significantly decreased (27% +/- 0.07) in occipital cortex contralateral to the affected hemifield. rCBV was decreased (15% +/- 0.12) and mean transit time increased (32% +/- 0.3), persisting up to 2.5 h into the headache phase. Other brain regions did not show significant perfusion changes. During migraine without aura, no significant hemodynamic changes were observed. In one patient who experienced both migraine with and without aura, perfusion deficits were observed only during migraine with aura. These findings suggest that decremental blood flow changes in occipital lobe are most characteristic of migraine with aura.