RESUMO
Moyna of Purba Medinipur district is widely known as an aquaculture hub of West Bengal, India. Though very good production is achievable from this fish culture system, management practices are inappropriate, which could create the sustainability problem of this culture system. The present study was thus undertaken for the estimation of plankton population, water quality, carbon footprint and carbon sequestration of this intensive aquaculture practices. Information on spawn to fry, fry to fingerlings and grow-out culture were collected through the structured questionnaire from the fish farmers. The plankton density, primary productivity, carbon footprint and carbon sequestration were analyzed using standard procedures. The phytoplankton, zooplankton and primary productivity were maximum at the stocking period and minimum during the middle of culture period. The lowest feed conversion ratio (FCR) was noticed with the minimum amount of feed applied in the pond. The CO2-e emission ranged from 0.56 to 4.89 kg CO2-e/kg fish (av. 2.13) for the production levels of 5.0 to 10.7 t/ha/yr. The pond water developed salinity and ammonium-N increased from 0.01 to 0.50 mg/l. The ponds with high feed loading (28 to 32 t/ha/yr) had the highest average sediment accumulation rate (11.0 ± 3.0 cm/yr) and carbon sequestration (704 ± 30 g C/m2/yr).
Assuntos
Pegada de Carbono , Sequestro de Carbono , Animais , Dióxido de Carbono , Aquicultura , Índia , PlânctonRESUMO
A cross sectional observational study was conducted to assess knowledge, attitude and practices about leprosy among leprosy patients in six districts of West Bengal. Total patients selected for the study were 300; of them 185 patients were from three high prevalent districts and 115 from three low prevalent districts of West Bengal. 56.33% patients were male and 43.67% were female. Most of the patients (85.67%) belonged to Hindu community and 60% from socially backward group. 64.33% patients lived below poverty line. Thirty five percentage of patients had correct knowledge that leprosy is caused by a bacteria. Patients from high prevalent districts (41.62%) have better knowledge than those from low prevalent areas (26.09%). Difference was found to be statistically significant (p = 0.006). Correct knowledge about spread of leprosy through cough & sneezing, of the patients from high prevalent districts (30.81%) was more than those from low prevalent districts (14.78%) (p = 0.001). 74.05% patients from high prevalent districts could tell one or other forms of clinical presentation of a leprosy patients, while 56.52% from low prevalent areas could mention it correctly (p = 0.01). About infectiousness, duration of treatment, complications, patients from high prevalent districts showed better knowledge that those from low prevalent districts. Similarly, Attitude of the patients towards leprosy was found to be more adverse in low prevalent areas. 90% patients have idea that leprosy was curable, but only 51.67% patients heard about MDT. Place of residence (high prevalent districts) & level of education (secondary & above) attributed to better knowledge score of the patients, whereas Place of residence (high prevalent districts) & age (younger age group) attributed to better attitude score of the patients.
Assuntos
Hanseníase/epidemiologia , Hanseníase/psicologia , Percepção , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Religião , Adulto JovemRESUMO
Wetlands are potential sites for mosquito breeding and are thus important in the context of public health. The use of chemical and microbial controls is constrained in wetlands in view of their potential impact on the diverse biota. Biological control using generalist aquatic insects can be effective, provided a preference for mosquito larvae is exhibited. The mosquito prey preferences of water bugs and larvae of odonate species were evaluated using chironomid larvae, fish fingerlings and tadpoles as alternative prey. Manly's selectivity (αi ) values with 95% confidence intervals (CIs) were estimated to judge prey preference patterns. Multivariate analysis of variance (manova) and standardized canonical coefficients were used to test the effects of density on prey selectivity. The αi values indicated a significant preference (P < 0.05) in all of the insect predators tested for mosquito larvae over the alternative prey as a density-dependent function. On a comparative scale, chironomid larvae had the highest impact as alternative prey. In a multiple-prey experiment, predators showed a similar pattern of preference for mosquito larvae over alternative prey, reflecting a significant (P < 0.05) niche overlap. The results suggest that, in a laboratory setting, these insect predators can effectively reduce mosquito density in the presence of multiple alternative prey.
Assuntos
Culicidae/fisiologia , Peixes/fisiologia , Preferências Alimentares , Insetos/fisiologia , Controle de Mosquitos , Comportamento Predatório , Animais , Anuros/fisiologia , Cadeia Alimentar , Índia , Larva , Densidade Demográfica , Áreas AlagadasRESUMO
A new genus, Neoschidium was erected with the type genus, Neoschidium phasma (Distant). It was earlier described under Ghilianella Spinola 1850 as G. phasma Distant and later under Schidium Bergroth 1916 as Schidium phasma (Distant) by Bergroth (1916). Because it exhibits characters not only of Ghilianella and Schidium but also intermediate specific characters that are not found in both the genera, the type genus Neoschidium phasma (Distant) is redescribed with additional taxonomic details, morphometrics, and illustrations. It is also recorded for the first time from India.
Assuntos
Biodiversidade , Reduviidae/classificação , Animais , Ecossistema , Índia , Masculino , Reduviidae/anatomia & histologiaRESUMO
Stroke is one of the leading cause of disability worldwide. Motor function deficits due to stroke contribute to overall low quality of life. The objective was of this study is to observe functional motor outcome after stroke with low dose Levodopa therapy. This prospective follow up study was carried out in the Department of Neurology, Mymensingh Medical College Hospital, Mymensingh, Bangladesh from July 2014 to June 2016 to see the effect of low dose of Levodopa (110mg) on motor outcome after stoke disability. Motor deficit was measured by Medical Research Council (MRC) grading and Rivermead Mobility Index (RMI) score. Two groups were selected by simple random method, consisted of both ischemic and hemorrhagic stroke. All the patients of both the groups were suffering from at least some post stroke motor disability and attended full course of physiotherapy. The group (L) received 110mg Levodopa with physiotherapy. On the other hand (NL) group received only physiotherapy. They were all followed up for four times within two months of time and were assessed for recovery of motor function. Mean age was 59.03±11.56 years in Levodopa (L) group and 57.10±12.41 years in the Non Levodopa (NL) group; Males were predominant in both groups. Ninety three (77.50%) cases had ischemic stroke and 27(22.50%) cases had hemorrhagic stroke. Most common risk factors were hypertension and smoking. No known risk factor was detected in 8 (6.67%) patients. Single or multiple risk factors were confirmed in 112 patients (93.33%). MRC score was significantly higher both in affected upper and lower limb in Levodopa group comparing non Levodopa group at 4th visit. RMI score was also significantly higher in Levodopa group comparing non Levodopa group at 4th visit. The Levodopa (L) group showed better recovery pattern than Non Levodopa (NL) group. It can be concluded that motor recovery was better with administration of a single low dose of Levodopa in combination with physiotherapy. Motor outcome was significantly higher in levodopa group than non-levodopa group.
Assuntos
Pessoas com Deficiência , Dopaminérgicos/uso terapêutico , Levodopa/uso terapêutico , Transtornos Motores/tratamento farmacológico , Acidente Vascular Cerebral/tratamento farmacológico , Idoso , Bangladesh , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Qualidade de VidaRESUMO
Auscultation, the technique of listening to heart sounds, remains a primary detection tool for diagnosing heart valve disorders. Other techniques, e.g. electrocardiography, ultrasound, etc, are accurate as well as informative; but expensive. With major advancement in the speed of computers, heart sound signals can be processed with ease by memory efficient digital signal processing and pattern recognition algorithms. This paper presents a digital signal processor (DSP) implementation of such a technique by using new threshold criteria. The proposed work can detect whether a heart sound recording belongs to a person suffering from valvular heart disease or not by giving 'diseased' or 'not diseased' decisions. The algorithm is tested for nine commonly occurring pathological problems and normal heart sound. The robustness of the algorithm is also checked against synthetically injected additive white Gaussian noise (AWGN) with different SNR levels. It is found to give an accuracy of 96.67% up to SNR values of 15 dB and 93.33% up to SNR values of 5 dB.
Assuntos
Algoritmos , Diagnóstico por Computador/métodos , Sopros Cardíacos/diagnóstico , Doenças das Valvas Cardíacas/diagnóstico , Fonocardiografia/métodos , Processamento de Sinais Assistido por Computador , Espectrografia do Som/métodos , Humanos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Stroke is leading cause of death world wide, after coronary artery disease and cancer. A high proportion of patients suffering from an acute stress such as stroke or myocardial infarction may develop hyperglycemia, even in the absence of a preexisting diagnosis of diabetes. An observational comparative study was carried out at the Department of Neurology and Medicine, Mymensingh Medical College, Mymensingh, Bangladesh from July 2011 to June 2013 among purposively selected ninety-three patients with a view to assess the outcome of stress hyperglycemia on acute stroke. Data were collected through interview, physical examinations & laboratory investigations by using case record form. Statistical analysis was performed using SPSS (Statistical package for social science) version 17. The mean age of this study was 59.04±15.01 years in the hyperglycemic group and 62.06±13.81 years in the normoglycemic group. The male female ratio in the Hyperglycemic and normoglycemic group was 2.12:1 and 2.44:1 respectively. Smoker was 48.8% in the hyperglycemic group and 52% in the normoglycemic group. 70% of the Hyperglycemic group and 66% of the normoglycemic were found hypertensive. Mean±SD blood glucose level was found 11.86±0.58mmol/L in the Hyperglycemic group and 6.50±1.55mmol/L in the normoglycemic group. Mean HbAlc were 6.14±0.56 in hyperglycemic group and 5.29±0.54 in normoglycemic group. Stroke severity score were 21.79±11.85 in Hyperglycemic and 28.64±9.53 in normoglycemic group on admission. Functional outcome was measured on discharge & at the end of 4th weeks of every patient by Glasgo Outcome Scale (GOS). The study also suggests that stress hyperglycemia is an important risk factor of poor stroke outcome.
Assuntos
Diabetes Mellitus , Hiperglicemia , Acidente Vascular Cerebral , Adulto , Idoso , Bangladesh , Glicemia , Feminino , Humanos , Hiperglicemia/complicações , Masculino , Pessoa de Meia-Idade , Prognóstico , Fatores de Risco , Acidente Vascular Cerebral/complicaçõesRESUMO
Stroke is one of the leading causes of death and disability in developed as well as developing countries like Bangladesh. There is a crucial need to identify additional risk factors that are easily measurable and treatable in general population. Role of serum lipids, lipoproteins and lipoprotein related variables in the prediction of stroke is less clear. Abnormalities in plasma lipoproteins are the most firmly established and best understood risk factors for atherosclerosis and they are probable risk factors for ischaemic stroke, largely by their link to atherosclerosis. High serum apolipoprotein-B (Apo-B) levels may predict an increased risk for ischaemic stroke. Aim of the study was to evaluate the association between serum Apo-B level and acute ischaemic stroke and to measure and compare serum Apo-B level in ischaemic stroke and normal subjects. A cross-sectional comparative study was carried out in the department of Neurology, Mymensingh Medical College Hospital, Mymensingh, Bangladesh from July 2013 to June 2015. A total number of 100 subjects within 18-70 years were considered for the study. Fifty (50) subjects with stroke (both clinically as well as CT scan of head or MRI of brain proven) were taken as the cases and 50 age and sex matched nearly healthy individuals without stroke were taken as the controls by using non-probability sampling procedure. Total cholesterol, HDL cholesterol and triglycerides were estimated by enzymatic method using Semiautoanalyser. LDL cholesterol was estimated by Friedewald formula. Apo-B was estimated by immunoturbidimetric method using Semiautoanalyser. Finally collected data were analyzed by using SPSS software Version 20. Student 't' test was used to compare the data between cases and controls. P value was set <0.05. Diagnostic validity tests were conducted to assess the diagnostic efficiency of Apo-B. Total cholesterol, LDL cholesterol and triglycerides are significantly increased in cases compared to controls. HDL-cholesterol was significantly decreased in cases compared to controls. Apo-B was significantly increased in cases compared to controls. The result was statistically significant. Apo-B may be used as predictors of ischaemic stroke components.
Assuntos
Isquemia Encefálica , Colesterol , Acidente Vascular Cerebral , Apolipoproteínas B/sangue , Bangladesh , Isquemia Encefálica/sangue , HDL-Colesterol , LDL-Colesterol , Estudos Transversais , Humanos , Acidente Vascular Cerebral/sangue , TriglicerídeosRESUMO
Methanol extract was prepared from the fronds of Pteris biaurita and partial purification was done by solvent partitioning with diethyl ether and ethyl acetate, followed by hydrolysis and further partitioning with ethyl acetate. The three fractions, thus obtained were bioassayed separately against five test fungi--Curvularia lunata, Fomes lamaoensis, Poria hypobrumea, Fuasrium oxysporum and a bacterium--Bacillus pumilus, by spore germination, radial growth and agar cup techniques. Results revealed that ethyl acetate fraction (III) contained the active principle. TLC plate bioassay of the active fraction revealed inhibition zone at an Rf of 0.5-0.65. Silica gel from this region was scraped, eluted in methanol and subjected to UV-spectrophotometric analysis. An absorption maxima of 278 nm was recorded. HPLC analysis of TLC-eluate revealed a single peak with retention time of 8.1 min. GC-MS analysis revealed six major peaks in the retention time range of 7.2-10.9 min. Comparison with GC-MS libraries revealed that the extracts may contain a mixture of eicosenes and heptadecanes.
Assuntos
Anti-Infecciosos/química , Pteris/química , Anti-Infecciosos/farmacologia , Cromatografia Líquida de Alta Pressão , Cromatografia em Camada Fina , Cromatografia Gasosa-Espectrometria de Massas , Pteris/crescimento & desenvolvimento , Pteris/fisiologia , Espectrofotometria UltravioletaRESUMO
Faecal contamination of groundwater from pit latrines is widely perceived as a major threat to the safety of drinking water for several billion people in rural and peri-urban areas worldwide. On the floodplains of the Ganges-Brahmaputra-Meghna delta in Bangladesh, we constructed latrines and monitored piezometer nests monthly for two years. We detected faecal coliforms (FC) in 3.3-23.3% of samples at four sites. We differentiate a near-field, characterised by high concentrations and frequent, persistent and contiguous contamination in all directions, and a far-field characterised by rare, impersistent, discontinuous low-level detections in variable directions. Far-field FC concentrations at four sites exceeded 0 and 10 cfu/100 ml in 2.4-9.6% and 0.2-2.3% of sampling events respectively. The lesser contamination of in-situ groundwater compared to water at the point-of-collection from domestic wells, which itself is less contaminated than at the point-of-consumption, demonstrates the importance of recontamination in the well-pump system. We present a conceptual model comprising four sub-pathways: the latrine-aquifer interface (near-field); groundwater flowing from latrine to well (far-field); the well-pump system; and post-collection handling and storage. Applying a hypothetical dose-response model suggests that 1-2% of the diarrhoeal disease burden from drinking water is derived from the aquifer, 29% from the well-pump system, and 70% from post-collection handling. The important implications are (i) that leakage from pit latrines is a minor contributor to faecal contamination of drinking water in alluvial-deltaic terrains; (ii) fears of increased groundwater pollution should not constrain expanding latrine coverage, and (iii) that more attention should be given to reducing contamination around the well-head.
Assuntos
Saúde Pública , Banheiros , Poluentes Químicos da Água , Bangladesh , Água Subterrânea , HumanosRESUMO
The Metrocoris fauna of India is reviewed and five new species are described from India: M. murtiensis Basu, Polhemus and Subramanian sp. nov. belonging to the nigrofasciatus species group, M. dinendrai Basu, Polhemus and Subramanian sp. nov. and M. darjeelingensis Basu, Polhemus and Subramanian sp. nov. of the compar species group, M. deceptor Basu, Polhemus and Subramanian sp. nov. (previously treated as M. quynhi Tran & Zettel in Basu et al., 2015) of the anderseni species group, and M. lavitra Basu, Polhemus, Subramanian and Saha sp. nov., which does not fit well into any currently established species group. The new species proposed are compared to all other known species, and a key to all the species of Indian Metrocoris is provided, accompanied by a table for comparison of key morphological characters, and a map and table of distributional details.
Assuntos
Heterópteros/anatomia & histologia , Heterópteros/classificação , Animais , Feminino , Heterópteros/crescimento & desenvolvimento , Índia , Masculino , Ninfa/anatomia & histologia , Especificidade da EspécieRESUMO
BACKGROUND & OBJECTIVES: The predatory behaviour with reference to the frequency-dependent prey-selection of the water bugs Sphaerodema annulatum Fabricius and S. rusticum Fabricius was studied in the laboratory using the IV instar larvae and pupae of Armigeres subalbatus as prey to ascertain their efficacy as predator of mosquito immatures. METHODS: Field collected adult morphs of the water bugs were allowed to predate on larvae and pupae provided in different ratios and densities as per the model of Greenwood and Elton' for a fixed time period. The data obtained on their predation rate were analysed with respect to the model parameters, lnV--the frequency independent component and b--the frequency dependent component of selection. RESULTS: It was found that the prey-selection was dependent on the relative numbers of prey available, favouring apostatic selection. The b values and lnV values for S. annulatum were 0.54 +/- 0.01 and 0.92 +/- 1.04 respectively whereas the corresponding values for S. rusticum were 0.71 +/- 0.03 and 0.17 +/- 1.57 respectively. INTERPRETATION & CONCLUSION: The selection of preys by the water bugs was dependent on the relative number of the prey forms and thus they are expected to predate on the form more abundant in a heterogeneous prey population and adversely affect the adult emergence.
Assuntos
Culicidae , Heterópteros/fisiologia , Modelos Biológicos , Comportamento Predatório/fisiologia , Animais , Índia , Larva , Densidade Demográfica , Análise de RegressãoRESUMO
A new stenopodaine reduviid, Aulacogenia darjeelingensis sp. nov. belonging to the "corniculata species group" from India is described and illustrated. A key to the Indian species of the genus Aulacogenia Stål is provided.
Assuntos
Reduviidae/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Índia , Masculino , Tamanho do Órgão , Reduviidae/anatomia & histologia , Reduviidae/crescimento & desenvolvimentoRESUMO
In tropical freshwaters, different species of water bugs (Heteroptera) constitute a guild sharing similar prey resources including chironomid and mosquito larvae. Assuming possibilities of intraguild predation (IGP) among the constituent members, an attempt was made to evaluate the effects of prey and predator density on the mortality of mosquito and chironomid larvae (shared prey), using Laccotrephes griseus Guérin-Méneville (Hemiptera: Nepidae) and Ranatra filiformis Fabricius (Hemiptera: Nepidae) as IG predators and Anisops bouvieri Kirkaldy (Hemiptera: Notonectidae) as IG prey. The predation on mosquito and chironomid larvae varied with the density and combinations of the predators. When present as conspecific IG predators, L. griseus exhibited greater effect on the prey mortality than R. filiformis. The effects on shared prey suggest that the two predators are not substitutable in terms of the effect on the shared prey mortality. The mortality of A. bouvieri (IG prey) at low shared prey density was significantly different (p < 0.05) from high shared prey density. In view of predatory effect of the heteropteran predators on the dipteran larvae, the results suggest possible interference by the presence of A. bouvieri as an intermediate predator. It seems that the presence of heteropteran predators including A. bouvieri as IG prey may benefit the dipteran prey under situations when the density is low in tropical waters. The intensity of the predatory effect may differ based on the species composition at IG predator level. For mosquito biological control, the interactions between the predators may not be substitutable and are independent in their effects.
Assuntos
Heterópteros/fisiologia , Comportamento Predatório , Animais , Culicidae , Larva , Densidade DemográficaRESUMO
A simple method for labeling human lymphocytes with Hg-197 is described. Lymphocytes were isolated from human blood and purified by the Ficoll-Hypaque method. Labeling was carried out by incubating viable cells suspended in saline with Hg-197 for different time intervals and at different temperatures. The labeling yield varied from 48% for 1 million cells to about 70% for 10 million cells after incubation with 2 muCi of Hg-197 for 2 hr at 37 degrees C. The temperature and incubation period beyond 1 hr had no appreciable effect on the labeling yield. The yield increased by a factor of 1.5 when the cells were stimulated by phytohemagglutinin. Subcellular distribution studies showed that 60% of the tracer localized in the nucleus and cell membrane, while the remaining portion concentrated in the mitochondrial and microsomal fractions.
Assuntos
Marcação por Isótopo , Linfócitos , Radioisótopos de Mercúrio , Humanos , Marcação por Isótopo/métodosRESUMO
The purpose of the present study is to prospectively compare myocardial perfusion imaging with rubidium-82 (82Rb) by positron emission tomography (PET) with thallium-201 (201Tl) imaging by single-photon emission tomography (SPECT) by recording both studies with a single dipyridamole handgrip stress, and reading both sets of images with the same display technique. In a series of 202 patients with previous coronary arteriography, the sensitivity, specificity, and accuracy of 82Rb PET were 93%, 78%, and 90% and for 201Tl SPECT 76%, 80%, and 77%, respectively. When 70 patients with previous therapeutic interventions were excluded, the remaining 132 patients showed a sensitivity, specificity, and accuracy of 95%, 82% and 92% for 82Rb PET and 79%, 76%, and 78% for 201Tl SPECT. The improved contrast resolution of PET resulted in markedly superior images and a more confident identification of defects.
Assuntos
Circulação Coronária/fisiologia , Doença das Coronárias/diagnóstico por imagem , Radioisótopos de Rubídio , Radioisótopos de Tálio , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada de Emissão , Doença das Coronárias/epidemiologia , Doença das Coronárias/fisiopatologia , Dipiridamol , Reações Falso-Negativas , Reações Falso-Positivas , Humanos , Processamento de Imagem Assistida por Computador , Estudos Prospectivos , Sensibilidade e EspecificidadeRESUMO
In a previous comparison of 202 consecutive patients who underwent myocardial perfusion imaging with both 201Tl SPECT and 82Rb PET, 27 patients were identified as having true-positive 82Rb images, but false-negative 201Tl images. The purpose of this report is to determine the effect of correct image interpretation of coronary artery disease on the final management of those patients and compare it to the previous management scheme wherein a negative image was usually accepted as the end point unless clinical symptoms dictated otherwise. A follow-up study of the clinical course and outcome of these studies showed that 63% (17/27) of the patients with a true-positive 82Rb PET image were recommended for revascularization procedures. It is doubtful that this majority of patients would have received either surgical or interventional management based on the false-negative 201Tl SPECT procedure alone.
Assuntos
Doença das Coronárias/diagnóstico por imagem , Radioisótopos de Rubídio , Radioisótopos de Tálio , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada de Emissão , Angioplastia Coronária com Balão , Ponte de Artéria Coronária , Doença das Coronárias/terapia , Vasos Coronários/diagnóstico por imagem , Reações Falso-Negativas , HumanosRESUMO
UNLABELLED: PET is useful in the presurgical evaluation of temporal lobe epilepsy. The purpose of this retrospective study is to assess the clinical use of statistical parametric imaging in predicting surgical outcome. METHODS: Interictal 18FDG-PET scans in 17 patients with surgically-treated temporal lobe epilepsy (Group A-13 seizure-free, group B = 4 not seizure-free at 6 mo) were transformed into statistical parametric imaging, with each pixel representing a z-score value by using the mean and s.d. of count distribution in each individual patient, for both visual and quantitative analysis. RESULTS: Mean z-scores were significantly more negative in anterolateral (AL) and mesial (M) regions on the operated side than the nonoperated side in group A (AL: p < 0.00005, M: p = 0.0097), but not in group B (AL: p = 0.46, M: p = 0.08). Statistical parametric imaging correctly lateralized 16 out of 17 patients. Only the AL region, however, was significant in predicting surgical outcome (F = 29.03, p < 0.00005). Using a cut-off z-score value of -1.5, statistical parametric imaging correctly classified 92% of temporal lobes from group A and 88% of those from Group B. CONCLUSION: The preliminary results indicate that statistical parametric imaging provides both clinically useful information for lateralization in temporal lobe epilepsy and a reliable predictive indicator of clinical outcome following surgical treatment.
Assuntos
Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/cirurgia , Lobo Temporal/diagnóstico por imagem , Tomografia Computadorizada de Emissão/métodos , Adulto , Desoxiglucose/análogos & derivados , Epilepsia do Lobo Temporal/epidemiologia , Feminino , Radioisótopos de Flúor , Fluordesoxiglucose F18 , Seguimentos , Humanos , Masculino , Valor Preditivo dos Testes , Psicocirurgia , Estudos Retrospectivos , Lobo Temporal/cirurgia , Fatores de Tempo , Resultado do TratamentoRESUMO
UNLABELLED: Multidetector SPECT systems equipped with a high-energy, or 511-keV collimator, have been proposed to offer a less expensive alternative to PET in myocardial viability studies with [18F]FDG. The objectives of this investigation included: (a) measuring the physical imaging characteristics of SPECT systems equipped with either a high-energy general-purpose collimator (HE), or the dedicated 511-keV collimator (UH), when imaging 511-keV photons, and comparing them with conventional FDG PET; and (b) directly and quantitatively comparing the diagnostic accuracy of SPECT, with either an UH or HE collimator, to that of PET in myocardial viability studies using 18F-FDG. METHODS: Physical imaging characteristics of SPECT and PET were measured and compared. Both SPECT and PET studies were performed in two groups of 18 patients each, with Group I using HE SPECT and Group II using UH SPECT. Myocardial perfusion studies were also performed using 82Rb PET at rest and during dipyridamole stress to identify areas of persistent hypoperfusion. For each myocardial region with a persistent perfusion defect, a perfusion-metabolism match or mismatch pattern was established independently, based on the results of 18F-FDG SPECT as well as PET. RESULTS: PET is superior to SPECT in all physical imaging characteristics, particularly in sensitivity and contrast resolution. PET had a sensitivity 40-80 times higher than that of SPECT, and its contrast resolution was 40-100% better than SPECT. Between FDG-SPECT using an HE collimator and that using a 511-keV collimator, the latter showed marked reduction in septal penetration (from 56% to 38%), improvement in spatial resolution (from 17 mm to 11 mm FWHM) as well as contrast resolution (from 34% to 45%), while suffering reduced system sensitivity (from 75 to 34 cpm/microCi). Patient studies demonstrated that although FDG-SPECT, using a HE or UH collimator, provided concordant viability information as FDG PET in a large majority of myocardial segments with persistent perfusion defects (88% and 90%, respectively), there is an excellent statistical agreement (kappa = 0.736) between SPECT with UH collimator and PET, while the agreement between SPECT using HE collimator and PET are moderate (kappa = 0.413). CONCLUSION: Despite its markedly inferior physical imaging characteristics compared with PET, SPECT with the dedicated 511-keV collimator offers a low-cost, practical alternative to PET in studying myocardial viability using [18F]FDG. SPECT systems with a high-energy, general-purpose collimator, on the other hand, are inadequate in such studies.
Assuntos
Desoxiglucose/análogos & derivados , Radioisótopos de Flúor , Coração/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada de Emissão , Circulação Coronária , Fluordesoxiglucose F18 , Humanos , Radioisótopos de Rubídio , Sensibilidade e EspecificidadeRESUMO
Positron emission tomography (PET) requires positron-emitting radionuclides that emit 511-keV photons detectable by PET imagers. Positron-emitting radionuclides are commonly produced in charged particle accelerators, eg, linear accelerators or cyclotrons. The most widely available radiopharmaceuticals for PET imaging are carbon-11-, nitrogen-13-, and oxygen-15-labeled compounds, many of which, either in their normal state or incorporated in other compounds, serve as physiological tracers. Other useful PET radiopharmaceuticals include fluorine-18-, bromine-75-, gallium-68 (68Ga)-, rubidium-82 (82Rb)-, and copper-62 (62Cu)-labeled compounds. Many positron emitters have short half-lives and thus require on-site cyclotrons for application, and others (68Ga, 82Rb, and 62Cu) are available from radionuclides generators using relatively long-lived parent radionuclides. This review is divided into two sections: cyclotrons and PET radiopharmaceuticals for clinical imaging. In the cyclotron section, the principle of operation of the cyclotron, types of cyclotrons, medical cyclotrons, and production of radionuclides are discussed. In the section on PET radiopharmaceuticals, the synthesis and clinical use of PET radiopharmaceuticals are described.