Using the modified Dixon technique to evaluate incidental adrenal lesions on 3T MRI. / Valoración mediante Dixon modificado de las lesiones suprarrenales incidentales en RM 3T.

OBJECTIVES: To use the mDIXON-Quant sequence to quantify the fat fraction of adrenal lesions discovered incidentally on CT studies. To analyze the relation between the signal loss between in-phase and out-of-phase T1-weighted sequences and the fat fraction in mDIXON-Quant. To compare the sensitivity and specificity of the two methods for characterizing adrenal lesions. MATERIAL AND METHODS: This prospective descriptive study included 31 patients with incidentally discovered adrenal lesions evaluated with 3T MRI using in-phase and out-of-phase T1-weighted sequences and mDIXON-Quant; the fat fraction of the adrenal lesions was measured by mDIXON-Quant and by calculating the percentage of signal loss between in-phase and out-of-phase T1-weighted sequences. RESULTS: The percentage of signal loss was significantly higher in the group of patients with adenoma (61.3% ± 20.4% vs. 5.1% ± 5.8% in the group without adenoma, p<0.005). The mean fat fraction measured by mDIXON-Quant was also higher for the adenomas (26.9% ±10.8% vs. 3.4% ± 3.0%, p<0.005).The area under the ROC curve was 0.99 (0.96 - 1.00) for the percentage of signal loss and 0.98 (0.94 - 1.00) for the fat fraction measured by mDIXON-Quant. The cutoffs obtained were 24.42% for the percentage of signal loss and 9.2% for the fat fraction measured by mDIXON-Quant. The two techniques had the same values for diagnostic accuracy: sensitivity 96% (79.6 - 99.9), specificity 100% (39.8 - 100.0), positive predictive value 100% (85.8 - 100.0), and negative predictive value 80% (28.4 - 99.5). CONCLUSION: The fat fraction measured by the modified Dixon technique can differentiate between adenomas and other adrenal lesions with the same sensitivity and specificity as the percentage of signal loss between in-phase and out-of-phase T1-weighted sequences.

Impact of a comprehensive law on the prevalence of tobacco consumption in Spain: evaluation of different scenarios.

OBJECTIVES: Since 2011, smoking legislation was hardened in Spain, banning tobacco consumption in all hospitality venues. Law 42/2010 was the first comprehensive tobacco control policy enacted in Spain. The aim of this paper is to evaluate the effect that this intervention has had in reducing the prevalence of tobacco consumption, setting up three scenarios on the basis of different theoretical levels of effect of the law. METHODS: A predictive model based on Markov Chains was developed to distinguish the effect of tobacco control policies in different scenarios. STUDY DESIGN: The model developed uses population, smoking rates and smoking characteristics from a non-transmissible disease surveillance system developed in Galicia (namely SICRI). RESULTS: Results show that tobacco control policies hardly affect the predicted trend in a temporal frame of 10 years, with relative reduction in the predicted male smoking prevalence of 20.4% with no intervention, reaching a reduction of 26.1% under the maximum effect of the policies. CONCLUSIONS: In the global population the effects of the law in the predicted prevalence have been barely perceived. For people under 25 years of age, interventions have had an important and positive effect, which proves that policies affecting this age group should be hardened.

Fagerstrom test for nicotine dependence vs heavy smoking index in a general population survey.

BACKGROUND: The Fagerström Test for Nicotine Dependence (FTND) is used for assessing nicotine dependence. A shorter test derived from the FTND used for the general population is the Heavy Smoking Index (HSI) (six questions vs. two). The objective of this study is to compare the validity of the HSI versus the FTND. METHODS: A survey of tobacco use in the general population was carried out in the northern Spanish region of Galicia using both the FTND and the HSI to study a representative sample of 1655 daily smokers. The HSI was compared with the FTND, considered the gold standard. Measures of sensitivity, specificity and predictive values were calculated. Concordance between the tests was also established (Cohen's kappa). RESULTS: Cohen's kappa showed good agreement between measures (Kappa = 0.7); specificity values were also high (Sp = 96.2%). Sensitivity analysis in females (Se = 62.3%) did not show good agreement. CONCLUSIONS: The HSI can be used as a reasonably good screening test in order to identify daily smokers with high nicotine dependence. Nevertheless, for populations or subpopulations having low nicotine dependence, such as women, the FTND is more reliable.

An evaluation of spatio-temporal models for the estimation of the mortality relative risk from breast cancer in Galicia, Spain.

BACKGROUND: Disease mapping is now a big focus of interest in the area of Public Health, and the geographical distribution of a disease has an important role in understanding its origin or its causes. The purpose of this work is to review and evaluate different techniques to map the mortality risk of a disease in small geographical areas. METHODS: Three different methods have been studied. The first one is a classical approach consisting of mapping SMRs, which are maximum likelihood estimates of the relative risk under a Poisson model of death counts. In a second step we consider Poisson and negative binomial regression to fit the rates and finally we use a Bayesian approach that assumes a hierarchical model where the death counts follow a Poisson distribution conditioned by the prior information. These methods have been applied to the study of geographical variation in female breast cancer mortality from 1976 to 1999 in the districts of Galicia, Spain. RESULTS: Mapping the SMRs using the first method has important drawbacks and there are difficulties to distinguish the mortality pattern. With the second method we achieved some improvements. The Bayesian methodology produces smoother maps with a clear mortality pattern. DISCUSSION: These methods are powerful tools for identifying areas with elevated risk. The Bayesian methodology has many advantages over the other methods that had been analysed in this work.