Relación entre el rendimiento en la prueba de estación unipodal y la velocidad del centro de presión en adultos mayores

Introduction

Frequent falls are one of the most important health problems in the elderly population. The unipedal stance test (UPST), asses postural stability and is used in fall risk measures. Despite this, there is little information about its relationship with posturographic parameters (PP) that characterizes postural stability. Center of pressure velocity (CoPV) is one of the best PP that describes postural stability. The aim of this study was to analyze the relation between UST score and CoPV in elderly population.

Materials and methods

A sample of 38 healthy elderly subjects where divided in two groups according to their UPST score, low performance (LP, n = 11) and high performance (HP, n = 27). The correlation between UPST score and COP mean velocity (CoPmV), recorded from a posturographic test, was analyzed between both groups.

Results

An inverse correlation between UPST score and CoPmV was found in both groups. However, this was higher in the LP group (r = −0.69, P = .02) compared to the HP (r = −0.39, P = .04).

Conclusions

Based on the results of this investigation, it may be concluded that the achievement on UPST has an inverse relationship with CoPmV, especially in subjects with low performance in the UPST.     

Factores asociados a la polifarmacia en población anciana no institucionalizada. Análisis de la submuestra de la Encuesta Nacional de Salud 2006 para personas mayores de Castilla y León

Background

The increase in chronic and degenerative diseases in the elderly leads to increased and multiple drug usage, which in turn leads to problems associated with adverse reactions and drug interactions.

Material and methods

We analysed the subsample of the National Health Survey 2006, for adults over 65 living in Castile-León (n = 458). Using a logistic regression model and correlation analysis the variables having more influence on polypharmacy were evaluated.

Results

A total of 86% of those interviewed claimed to be taking drugs and 93.9% had a chronic illness. The most common health problems included arthrosis, arthritis or rheumatism (53.5%) and hypertension (48.3%), and most frequently used drugs were hypotensives (45%), pain medications (37.1%) and those for rheumatism (21.4%). Both the mean number of illnesses suffered and the drugs consumed are significantly higher in those who claimed to have, “or or fair health, used the health services, had impaired eyesight and hearing, dependent for personal care and domestic tasks, and mobility (P < .05). The variables associated with polypharmacy are three or more chronic diseases (OR = 18.3), regular-poor self perceived health (OR = 3.4) and females (OR = 1.9).

Conclusions

Given the magnitude of the problem it would be appropriate to include a review of the medications in health examinations of the elderly, particularly in women older than 75 years, with regular or self-perceived poor health and who have 3 or more diseases.     

Resultados de la endarterectomía carotídea en pacientes ancianos

Introduction

Forty-five per cent of stoke patients have a surgically accessible stenosis. The objective of our study is to describe the response to carotid endarterectomy (EA) in patients of advanced age compared to younger ones.

Material and method

Retrospective evaluation of the clinical history of all patients who underwent an endarterectomy in a tertiary hospital between January 1995 and December 2006. The patients were grouped into those 75 years or older and those less than this age. The incidence of peri-operative complications in the first month after surgery, and the long-term mortality was evaluated using a survival analysis.

Results

Data were collected on 147 EA in 134 patients of 75 years or more, and on 201 EA in 177 patients less than 75 years-old. The incidence of peri-operative complications was similar in both groups, with a mortality of 2% in the older age group and a stroke incidence of 2.6% (half transient ischaemic accidents). The older patients had a mean follow-up of 4.1 years, with a survival of 86% at one year and 54% at 5 years and with the main cause of death being heart disease.

Conclusions

Carotid EA is a safe and effective technique for the treatment of extracranial carotid stenosis in the elderly, having the same peri-operative morbidity and mortality as younger ones. Age must not affect our therapeutic attitude, although an exhaustive cardiology study must be made in the elderly prior to the operation.     

Evaluación breve del estado cognitivo de la demencia en estadios avanzados: resultados preliminares de la validación española del Severe Mini-Mental State Examination

Introduction

The cognitive assessment of patients with advanced dementia needs proper screening instruments that allow obtain information about the cognitive state and resources that these individuals still have. The present work conducts a Spanish validation study of the Severe Mini Mental State Examination (SMMSE).

Material and methods

Forty-seven patients with advanced dementia (Mini-Cognitive Examination [MEC]<11) were evaluated with the Reisberg's Global Deterioration Scale, MEC, SMMSE and Severe Cognitive Impairment Profile scales.

Results

All test items were discriminative. The test showed high internal ( α = 0.88), test-retest (0.64 to 1.00, P < .01) and between observers reliabilities (0.69-1.00, p < 0.01), both for scores total and for each item separately. Construct validity was tested through correlations between the instrument and MEC scores (r = 0.59, P < 0.01). Further information on the construct validity was obtained by dividing the sample into groups that scored above or below 5 points in the MEC and recalculating their correlations with SMMSE. The correlation between the scores in the SMMSE and MEC was significant in the MEC 0-5 group (r = 0.55, P < .05), but not in the MEC>5 group. Additionally, differences in scores were found in the SMMSE, but not in the MEC, between the three GDS groups (5, 6 and 7) (H = 11.1, P < .05).

Conclusions

The SMMSE is an instrument for the assessment of advanced cognitive impairment which prevents the floor effect through an extension of lower measurement range relative to that of the MEC.From our results, this rapid screening tool and easy to administer, can be considered valid and reliable.     

Síntomas depresivos en adultos mayores participantes de una universidad abierta a la tercera edad

Introduction

Although depressive disorders prevalence among older adults usually is less than in the younger population, the presence of significant symptoms of depression is common in elderly people. Studies show that taking part in social, educational and pleasure activities is associated with a reduction in depressive symptoms in this population. The purpose of this study was to examine the prevalence of depressive symptoms above the elderly participants of a Third Age Open University, taking the time taking part as a reference.

Material and methods

A cross-sectional design was implemented, with a participation of 95.2% (n = 140) of the total enrolled in the first trimester of 2009 in the activities of the Third Age Open University of the Schools of Arts, Sciences and Humanities of the University of São Paulo. They all answered a socio-demographic questionnaire and the Geriatric Depression Scale (GDS-15).

Results

The prevalence of depressive symptoms found was 3.57%. The statistical analysis showed a relationship between participation formore than one semester in the Third Age Open University and a lower index of depressive symptoms (p < .05).

Conclusions

Participating for longer than one academic semester is associated with less depressive symptoms, possibly being a protector factor against depression.     

Características de la fractura de cadera y posterior recuperación en pacientes mayores de 65 años con historia de caídas recurrentes

Recurrent falls affect between 14.8% and 19% of the elderly population, and are associated with an increased risk of fracture. We know little about the influence the history of recurrent falls may have on recovery after hip fracture.

Methods

Cohort study. The patients included were, over 65 years admitted during a 1 year period to the General University Hospital of Albacete with a hip fracture due to a fall. Recurrent falls were defined as a history of two or more falls within the 6 months prior to the fracture. Variables: demographic data, circumstances of fall, number of falls in the previous 6 months, type of fracture and its repair, comorbidity and drug treatment, cognitive status at admission (Pfeiffer test) and independence for activities of daily living (Barthel Index - BI) were collected. A subsample of patients with pre-fracture BI≥60 and Pfeiffer at admission≤4 was followed up at 3, 6 and 12 months.

Results

A total of 335 patients were admitted. Data were collected on 279 of them, 19.4% of whom had previously suffered two or more falls. The recurrent fallers had a worse mental status on admission, a higher number of associated diseases, a lower percentage of independence in dressing and in bed-chair transferring than patients without history of recurrent falls, all statistically significant. In the 201 patients followed up, the impairment on the BI after 12 months compared to the BI previous to fracture was higher in recurrent fallers (-20.8 ± 31.54 vs -10.73 ± 20.21, P = .04), focusing more on independence in eating (76% vs 91.9%, P < .05), grooming (72% vs 91,9%, P < .01), faecal continence (60% vs 78.7%, p < .05) and walking indoors (80% vs 93.3%, P < .05).

Conclusions

The recovery of independence after hip fracture is significantly lower in the group of recurrent fallers in patients without moderate or severe functional impairment previous to fracture and cognitively stable.     

Tomographie par émission de positons au F-fluorodeoxyglucose dans la mise en évidence de la maladie veineuse thromboembolique

Purpose

Association of venous thromboembolism (VTE) and inflammation reported in the literature may allow the use of FDG PET/CT in the detection of thrombotic process. Published studies remain limited and contradictory. The aim was, therefore, to evaluate the performance of FDG PET/CT for the detection of VTE.

Patients and methods

Patients included in a prospective study evaluating FDG PET/CT for the detection of malignancy in patients with idiopathic VTE were analysed (MVTEP, PHRC 2008). PET/CT images were interpreted initially without and then retrospectively with knowledge of VTE locations.

Results

Hundred and fourteen patients were included in MVTEP study from March 13th 2009 to July 1st 2010. Forty-six patients (median age: 74 years [20-87], 27 males, 19 females) were analysed. No abnormal uptake was initially reported in pulmonary vessels. The retrospective analysis of pulmonary embolism locations did not demonstrate any significant difference in FDG uptake between embolic sites and controlateral vessels (P = 0.883). Initial analysis of lower limbs vessels demonstrated sensitivity and specificity of PET/CT for deep venous thrombosis (DVT) diagnosis of 15 and 99%. The metabolic activity of DVT was significantly higher than the activity of controlateral vessels (P < 0.005) but without showing any significant SUV threshold for DVT diagnosis.

Conclusion

In conclusion, there is insufficient evidence to suggest that FDG PET/CT could be accurate in detection of VTE. These results need to be completed in a larger study with shorter delay between VTE and FDG PET/CT.     

Medida de la capacidad funcional y la calidad de vida relacionada con la salud de un grupo de personas mayores que llevan a cabo un programa de caminatas: estudio piloto

Introduction

This pre-experimental study analyses the Functional Capacity (FC), Body Mass Index (BMI), Health Related Quality of Life (HRQoL) and Health Capital Stock (HCS) of elderly people participating in a Walking program in Granollers (Barcelona).

Material and methods

One hundred and seventy-three participants were invited to participate. One hundred and one of them were users of the Municipal Program for Elderly People, and 72 received information by the communication media. One hundred and thirty-one (76.3%) of the participants completed the Program.The intervention consisted of a 6-month program, supervised by a specialist instructor once a week and controlled daily by a pedometer.The 6-minute walk test (6MWT) was analysed for the FC, and the EuroQoL for the HRQoL. The preferences derived from the EuroQoL scores and the Life Expectancy were used to calculate the FC. The monetary data were obtained using a fixed value.

Results

An increase in the average number of steps was observed after the program, especially in men. The results also showed a decrease in the BMI. The participants showed a improvement in overall health perception at the end of the program. The HCS scores confirmed the improvement in the HRQoL in men.

Conclusions

The Program was positive for increasing the number of steps and improving physical condition and health. The usefulness of the pedometer as a motivational tool of physical exercise is discussed.     

Fragilidad y dependencia en Albacete (estudio FRADEA): razonamiento, diseño y metodología

Objective

To obtain a cohort of subjects of equal to or greater than 70 years, representative of a Spanish urban population, to estimate the prevalence of frailty and follow it up over time to analyse associated factors.

Material and methods

A prospective, population-based cohort study. From a population of 18,137 elderly persons, a representative sample of 1172 was randomly stratified, of which 993 (84.7%) agreed to take part. The variables collected were; sociodemographic, comorbidity, functional (n = 825), cognitive, affective and quality of life. On the patients who agreed, body composition was determined by bioimpedance analysis (n = 557), basal metabolic rate by indirect calorimetry (n = 450) and a blood sample was obtained for biomarkers (n = 859). Frailty was defined by the presence of 3 or more Fried criteria: unintentional weight loss, low energy, exhaustion, slow walking, and low physical activity. The cohort will be followed up over time until the death of the subjects.

Results

Mean age 79.4 (SD 6.4) years, with 601 (60.5%) women. A total of 21.3% were institutionalised; 16.9% were frail, 48.5% pre-frail, 21.3% non-frail, and 12.8% did not have the 3 criteria to be able to determine their state, of which 9.5% had moderate-severe incapacity, which would increase the prevalence of frailty to 26.4%.

Conclusions

A FRADEA cohort has been constructed, representative of an urban population in Spain. The prevalence of frailty in the cohort was 16.9%.     

Características antropométricas,funcionales y de fuerza explosiva de mujeres mayores de 50 años físicamente activas de la ciudad de Bogotá, Colombia

Objective

To analyze the relationship between different test measuring explosive strength and functionality of active women participating in a leisure sport program in order to describe the caracteristics of health status and look for tools for diagnosing and monitoring degenerative process.

Methods

This study was conducted on 102 women physically active and without risk factors. Anthropometric, functional independence and explosive strength tests were applied.

Results

Mean age 60.08±5.35 years; body mass index: 26.81±3.91; percentage of fat: 52.45±4.75; percentage of muscle mass: 37.24±6.77; tests of functional independence: maximum speed (30 meters): 9.39±1.92 s; speed-agility (30 meters): 12.93±1.59 s, and dynamic balance (6 meters): 21.9±8.01 s. Explosive Strength (Bosco test): Squat Jump: 12.23±3.05 cm, Countermovement Jump: 13.18±3.04 cm and Countermovement Jump Arm swing: 14.80±4.01 cm.

Conclusion

The statistical relationships found between body composition, explosive strength and functionality tests, are important tools for diagnosing and monitoring, and could improve the intervention models on the elderly.     

Study of the insulin signaling pathways in the regulation of ACAT1 expression in cultured macrophages

Objective

To determine the signaling pathways and components involved in insulin-mediated regulation of Acyl-CoA: cholesterol acyltransferase1 (ACAT1).

Methods

THP-1 cells were cultured in RPMI 1640 medium and were induced into macrophages in the presence of 160 nM phorbol 12-myristate 13-acetate (PMA). Before insulin was added in, macrophages were preincubated with the inhibitors of the insulin signaling pathway, including wortmannin, phosphatidylinositol 3-kinase (PI3 K) inhibitor; PD98059, extracellular signal-regulated kinase (ERK) inhibitor; SB203580, p38 mitogen-activated protein kinase (p38MAPK) inhibitor; SP600125, c-Jun N-terminal kinase (JNK) inhibitor and U73122, phospholipase C-γ (PLC-γ) inhibitor. ACAT1 mRNA and protein expression level in macrophages were determined by real-time quantitative polymerase chain reaction and western blotting, respectively.

Results

Real-time quantitative polymerase chain reaction and western blotting demonstrated that PD98059, SB203580 or SP600125 down-regulated the expression of ACAT1 in a dose-dependent manner. However, no obvious alteration was found in wortmannin and U73122 groups.

Conclusion

These results suggest that the ERK, p38MAPK and JNK signaling pathways may be involved in insulin-mediated regulation of ACAT1, but no PI3K and PLC-γ signaling pathways were involved in the present study.     

Utilización del servicio de urgencia de un hospital universitario por los adultos mayores en Santiago de Chile

Introduction

An increase in visits to Emergency Departments by older adults has been reported, but there are no data available on this in countries in the early phases of demographic and epidemiological transition. This paper describes the characteristics of people over 60 years-old (AM) who visited the Emergency Department of the Hospital Clínico Universitario de la Pontificia Universidad Católica, Chile (SU-PUC), compared to those less than 60 years-old (AJ).

Material and methods

Demographic data and reasons for admission and re-admission were collected retrospectively from the SU-PUC monthly statistics report. Obstetrics, paediatrics and «scheduled admissions» were excluded. The frequencies were compared using Chi-squared (significance: P < .05).

Results

A total of 37,660 visits to the SU-PUC were recorded (81% AJ; 19% AM; with 8% being older than 75 years). No statistical differences were found in the visit time (70% daytime), or by season between the groups.A total of 7,414 (19.6%) of those who visited were hospitalised, with differences being detected between groups (AM: 48.9% vs 12.9% AJ; P < .001), particularly in those over 75 years (59%). The primary cause of admission was cardiopulmonary in AM (22%) and gastrointestinal in AJ (31%). Re-admissions were 10% in AM and 6% in AJ (P < .001).

Conclusion

The use of SU by AM and some characteristics of their care process (hospitalisation) are similar to those found in countries in more advanced phases of demographic transition.     

Evaluación de un programa de intervención en residencias geriátricas para reducir la frecuentación hospitalaria

Objectives

This study describes the outcomes of an intervention program in Nursing Homes and their effects on emergency room attendance, hospital admissions, and pharmaceutical expenditure.

Material and methods

This involved non-randomised community intervention in Nursing Homes with a control group. The program was implemented gradually from 2007 to 2009 in 10 Nursing Homes (857 beds) which participated voluntarily. The control group consisted of 14 Nursing homes (1,200 beds), which refused to participate or were not assigned to our Primary Care centres. Intervention consisted of comprehensive geriatric assessment and follow-up visits by trained personnel, review and adjustment of drug treatment, case management and staff training.

Results

In the Nursing Homes where the program was carried out, emergency room attendance decreased from 1165‰ (95%CI 1100-1240]) in 2006 to 674‰ (95%CI 620-730) in 2009, while in the control group it increased from 1071 (95%CI 1020-1130) to 1246‰ (95%CI 1190-1310). The hospital admissions also decreased from 48.4% (95%CI 45-52) in 2006 to 32.1% (95%CI 29-35) in 2009, while in the control group increased from 43.5% (95%CI 41-46) to 55.8% (95%CI 53-59). There was also a 9% reduction in pharmacy cost compared with an increase of 11.9% in the control group.

Conclusions

The intervention has proved effective at reducing hospital admissions and emergency room attendance in institutionalised patients, thereby streamlining pharmacy costs.     

Apport de deux techniques d’analyse automatisées des examens [F] FDG TEP dans la discrimination des patients déments frontotemporaux et malades d’Alzheimer

Introduction

In younger patients, the in vivo clinical diagnosis of Alzheimer's disease (AD) and of the frontotemporal type (FTD) may be cumbersome. The gold standard diagnostic proof is currently still based upon pathology examination. It is crucial to find reliable techniques to make an accurate in vivo diagnosis and to differentiate the etiology of the dementia.

Patients and method

Twenty-four patients bearing clinically diagnosed AD (n = 16) and FTD (n = 8) underwent [¹⁸F] FDG-PET/CT brain scan. Four nuclear medicine physicians with varying expertise in neuroimaging read each scan according to: visual analysis; automated analysis computed by BRASS^® Hermes^® software; automated analysis computed by Cortex ID^® General Electric^® software. Interpretation aimed at assessing the global scan aspect, the cerebral metabolism per hemisphere (in five relevant regions) and the diagnostic degree of confidence. Diagnostic interpretations derived from visual and automated analyses were compared to clinical diagnosis. Inter-observer agreement and Kappa scores were calculated.

Results

Kappa analyses showed a gain in diagnostic accuracy for a nonexpert physician, a gain in diagnostic confidence with Cortex ID^® and a gain in interobserver diagnostic agreement with BRASS^®.

Conclusion

Using automated software such as Cortex ID^® or BRASS^® helps standardizing the interpretation of [¹⁸F] FDG distribution pattern in AD or FTD.     

Protective effect of tetramethylpyrazine isolated from Ligusticum chuanxiong on nephropathy in rats with streptozotocin-induced diabetes

Purpose

This study was designed to investigate the protective effect of tetramethylpyrazine isolated from Ligusticum chuanxiong, a traditional Chinese medicine, on diabetic nephropathy in a rat model, and to explore the possible mechanism involved in a protective function.

Materials

Diabetes was induced in male Sprague-Dawley rats by a single intraperitoneal injection of 70 mg/kg of streptozotocin. One week later, 200 mg/kg/day of tetramethylpyrazine was administered intragastric gavage daily for 8 weeks. Renal functions and expression of vascular endothelial growth factor were examined at 4 and 8 weeks after tetramethylpyrazine administration.

Results

Blood glucose and renal function were significantly improved in the tetramethylpyrazine-treated group compared to the untreated diabetic rats. Diabetic nephropathy resulted in an increase in the expression of vascular endothelial growth factor, while tetramethylpyrazine administration greatly decreased the expression.

Conclusions

Our results suggest that administration of tetramethylpyrazine may reduce kidney damage caused by diabetes. This protective effect may be mediated, in part, by downregulated expression of vascular endothelial growth factor in the kidney.     

Selective changes in white matter integrity in MCI and older adults with cognitive complaints

Background

White matter changes measured using diffusion tensor imaging have been reported in Alzheimer's disease and amnestic mild cognitive impairment, but changes in earlier pre-mild cognitive impairment stages have not been fully investigated.

Methods

In a cross-sectional analysis, older adults with mild cognitive impairment (n = 28), older adults with cognitive complaints but without psychometric impairment (n = 29) and healthy controls (n = 35) were compared. Measures included whole-brain diffusion tensor imaging, T1-weighted structural magnetic resonance imaging, and neuropsychological assessment. Diffusion images were analyzed using Tract-Based Spatial Statistics. Voxel-wise fractional anisotropy and mean, axial, and radial diffusivities were assessed and compared between groups. Significant tract clusters were extracted in order to perform further region of interest comparisons. Brain volume was estimated using FreeSurfer based on T1 structural images.

Results

The mild cognitive impairment group showed lower fractional anisotropy and higher radial diffusivity than controls in bilateral parahippocampal white matter. When comparing extracted diffusivity measurements from bilateral parahippocampal white matter clusters, the cognitive complaint group had values that were intermediate to the mild cognitive impairment and healthy control groups. Group difference in diffusion tensor imaging measures remained significant after controlling for hippocampal atrophy. Across the entire sample, diffusion tensor imaging indices in parahippocampal white matter were correlated with memory function.

Conclusions

These findings are consistent with previous results showing changes in parahippocampal white matter in Alzheimer's disease and mild cognitive impairment compared to controls. The intermediate pattern found in the cognitive complaint group suggests the potential of diffusion tensor imaging to contribute to earlier detection of neurodegenerative changes during prodromal stages. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.     

Eficiencia de las unidades geriátricas de agudos: metaanálisis de estudios controlados

Objective

After analysing the effectiveness in the reduction in the incidence of functional impairment and a higher probability of returning home between elderly patients hospitalised due to an acute medical illness cared for in acute geriatric units (AGU) compared to conventional care units, we propose to assess the efficiency of this care.

Material and methods

A systematic review and meta-analysis was made of controlled studies (randomised, no randomised and case-control) that compared care in UGA with care in conventional hospital units of patients of 65 years and over with an acute medical illness. Studies on administrative data bases, those that evaluated care of a single disease, and those that assessed units with care in the acute and sub-acute phase were excluded. A literature review was performed on articles published up to 31st of August 2008 in Medline, Embase, Cochrane Library, and references of systematic reviews and reviewed articles. The selection of the studies and the extraction of data on the hospital stay and care costs was made independently by two different researchers.

Results

A total of 11 studies were included, of which 5 were randomised, 4 were non-randomised, and 2 case control, all of them providing data on hospital stay, with 7 of them providing data on hospital costs (4 clinical trials, 2 non-randomised and 1 case-control). The overall analysis of all the studies showed that those admitted to UGA had a statistically significant reduction in hospital length of stay compared to the elderly hospitalised in conventional units (mean difference -1.01 days; 95% CI, -1.66 to -0.36) and hospital care costs (mean difference of -330 US dollars; 95% CI, -540 to -120).

Conclusions

Care in AGU is more efficient than that provided in conventional units, since, as well as achieving a reduction in the incidence of functional impairment at discharge and increasing the probability of returning home, they reduce mean hospital stay and the hospital care costs.     

Calidad de vida y sobrecarga de los cuidadores de pacientes con daño cerebral adquirido

Introduction

The health impact of acquired brain injury (ABI) is not only apparent in the patient, but also in the loss of health related quality of life (HRQol) of their carers. The objectives of this study were to measure the loss of HRQol as well as the burden of the carers of patients with ABI.

Material and methods

A retrospective study was conducted with 76 carers of patients with ABI. A questionnaire was used to collect information on the sociodemographic aspects, carer burden (Zarit Scale) and the HRQol (EuroQol Questionnaire) of the carers. A multiple linear regression model was constructed to analyse the effect of the different variables.

Results

The carers were predominantly women over 50 years, retired or dedicated to domestic tasks and who cared for their husband or one of their parents. One third showed a high risk of claudication. The mean HRQol obtained with the EuroQol went from a similar score to that of the general population (0.9) in the group without burden, to 0.67 in the group with risk of claudication. The regression models explained the burden better than the loss in quality of life.

Conclusions

Carers of patients with brain injury suffer a significant loss in HRQol compared to the general population. The deterioration arises from the mental dimensions and depends on the level of burden.     

Évaluation de méthodes automatiques de segmentation des volumes tumoraux en tomographie par émission de positons par comparaison avec des contours manuels réalisés par un groupe d’experts

Objective

Set up a framework for evaluating automatic segmentation methods of tumour volumes on PET images.

Patient and methods

This study was performed with PET images of 18 patients with non-Hodgkin's lymphoma. One target lesion per patient was pointed out. Each lesion was then three times manually delineated by five experts. Four automatic methods (the application of a threshold of 42% of the maximum SUV, the MIP-based method, the Daisne et al. method and the Nestle et al. method) were evaluated by comparison with the set of manual delineations.

Results

From the manual delineations, we have concluded to a moderate intra-operator variability and to a reduced interoperator reproducibility. From statistical tests performed on various quantitative criteria, there was no significant difference between the MIP-based method, the Daisne et al. method and the Nestle et al. one. The application of a threshold of 42% of the maximum SUV appears to be less efficient.

Conclusion

This work proposes a comparison and an evaluation protocol for segmentation methods. The generated data set will be distributed online for the community to simplify the evaluation of any new method of segmentation.