Resumo Objetivo: O objetivo deste estudo foi avaliar os achados de tomografia computadorizada de alta resolução (TCAR) em pacientes com diagnóstico de calcificação pulmonar metastática (CPM). Materiais e Métodos: Revisamos, retrospectivamente, os achados na TCAR de 23 casos de CPM [14 homens e 9 mulheres; idade média, 54,3 (intervalo, 26-89) anos]. Os pacientes foram examinados entre 2000 e 2014 em nove hospitais terciários no Brasil, Chile e Canadá. O diagnóstico foi estabelecido por estudo histopatológico em 18 pacientes e correlação clinicorradiológica em 5 pacientes. Dois radiologistas de tórax analisaram as imagens e chegaram a decisões por consenso. Resultados: Os achados predominantes na TCAR foram nódulos centrolobulares em vidro fosco (n = 14; 60,9%), consolidação com alta atenuação (n = 10; 43,5%), pequenos nódulos densos (n = 9; 39,1%), opacidades reticulares periféricas associadas com pequenos nódulos calcificados (n = 5; 21,7%) e opacidades em vidro fosco sem nódulos centrolobulares em vidro fosco (n = 5; 21,7%). Calcificação vascular na parede torácica foi encontrada em quatro casos e derrame pleural foi observado em cinco casos. As anormalidades foram bilaterais em 21 casos. Conclusão: CPM manifestou-se com três padrões principais na TCAR. O aspecto mais comum foram os nódulos centrolobulares em vidro fosco, frequentemente contendo calcificações, seguido de consolidação densa e de pequenos nódulos sólidos, a maioria deles calcificada. Também descrevemos o padrão de opacidades reticulares periféricas associadas a pequenos nódulos calcificados. Esses achados devem sugerir o diagnóstico de CPM no contexto de hipercalcemia.

Abstract Objective: The aim of this study was to evaluate the high-resolution computed tomography (HRCT) findings in patients diagnosed with metastatic pulmonary calcification (MPC). Materials and Methods: We retrospectively reviewed the HRCT findings from 23 cases of MPC [14 men, 9 women; mean age, 54.3 (range, 26-89) years]. The patients were examined between 2000 and 2014 in nine tertiary hospitals in Brazil, Chile, and Canada. Diagnoses were established by histopathologic study in 18 patients and clinical-radiological correlation in 5 patients. Two chest radiologists analyzed the images and reached decisions by consensus. Results: The predominant HRCT findings were centrilobular ground-glass nodules (n = 14; 60.9%), consolidation with high attenuation (n = 10; 43.5%), small dense nodules (n = 9; 39.1%), peripheral reticular opacities associated with small calcified nodules (n = 5; 21.7%), and ground-glass opacities without centrilobular ground-glass nodular opacity (n = 5; 21.7%). Vascular calcification within the chest wall was found in four cases and pleural effusion was observed in five cases. The abnormalities were bilateral in 21 cases. Conclusion: MPC manifested with three main patterns on HRCT, most commonly centrilobular ground-glass nodules, often containing calcifications, followed by dense consolidation and small solid nodules, most of which were calcified. We also described another pattern of peripheral reticular opacities associated with small calcified nodules. These findings should suggest the diagnosis of MPC in the setting of hypercalcemia.

Resumo Objetivo: Analisar, retrospectivamente, as tomografias computadorizadas de alta resolução (TCAR) de pacientes com microlitíase alveolar pulmonar, a fim de avaliar a frequência dos padrões tomográficos e sua distribuição no parênquima pulmonar. Materiais e Métodos: O estudo incluiu 13 pacientes (9 femininos e 4 masculinos) com idades variando de 9 a 59 anos (média de 34,5 anos). Os exames foram avaliados por dois observadores, de modo independente, e os casos discordantes, resolvidos por consenso. O critério de inclusão foi a presença de anormalidades na TCAR típicas de microlitíase alveolar pulmonar, o que prescinde a necessidade de exame histopatológico. Entretanto, em 6 casos foram realizadas biópsias pulmonares. Resultados: Os achados tomográficos predominantes foram opacidades em vidro fosco e pequenos nódulos parenquimatosos, presentes em 100% dos casos, seguidos de pequenos nódulos subpleurais (92,3%), cistos subpleurais (84,6%), calcificações lineares subpleurais (69,2%), padrão de pavimentação em mosaico (69,2%), fissura nodular (53,8%), calcificação ao longo dos septos interlobulares (46,2%) e consolidações densas (46,2%). Conclusão: Quanto à distribuição dos achados, houve acometimento preferencial dos terços inferiores. Não foi observado predomínio de distribuição dos sentidos axial e anteroposterior

Abstract Objective: The present study was aimed at retrospectively reviewing high-resolution computed tomography (HRCT) findings in patients with pulmonary alveolar microlithiasis in order to evaluate the frequency of tomographic findings and their distribution in the lung parenchyma. Materials and Methods: Thirteen patients (9 females and 4 males; age, 9 to 59 years; mean age, 34.5 years) were included in the present study. The HRCT images were independently evaluated by two observers whose decisions were made by consensus. The inclusion criterion was the presence of abnormalities typical of pulmonary alveolar microlithiasis at HRCT, which precludes lung biopsy. However, in 6 cases lung biopsy was performed. Results: Ground-glass opacities and small parenchymal nodules were the predominant tomographic findings, present in 100% of cases, followed by small subpleural nodules (92.3%), subpleural cysts (84.6%), subpleural linear calcifications (69.2%), crazy-paving pattern (69.2%), fissure nodularity (53.8%), calcification along interlobular septa (46.2%) and dense consolidation (46.2%). Conclusion: As regards distribution of the lesions, there was preferential involvement of the lower third of the lungs. No predominance of distribution in axial and anteroposterior directions was observed.

Objective: To evaluate the predictive efficiency of two statistical models (one parametric and the other non-parametric) to predict critical episodes of air pollution exceeding daily air quality standards in Santiago, Chile by using the next day PM10 maximum 24h value. Accurate prediction of such episodes would allow restrictive measures to be applied by health authorities to reduce their seriousness and protect the community's health. Methods: We used the PM10 concentrations registered by a station of the Air Quality Monitoring Network (152 daily observations of 14 variables) and meteorological information gathered from 2001 to 2004. To construct predictive models, we fitted a parametric Gamma model using STATA v11 software and a non-parametric MARS model by using a demo version of Salford-Systems. Results: Both models showed a high correlation between observed and predicted values. However, the Gamma model predicted PM10 values below 240µg/m³ more accurately than did MARS. The latter was more efficient in predicting PM10 values above 240µg/m³ throughout the study period. Conclusion: MARS models are more efficient in predicting extreme PM10 values and allow health authorities to adopt preventive methods to reduce the effects of these levels on the population's health. The reason for this greater accuracy may be that MARS models correct variations in the series over time, thus better fitting the curve associated with PM10 concentrations.

Objetivo: Evaluar la eficiencia predictiva de modelos estadísticos paramétricos y no paramétricos para predecir episodios críticos de contaminación por material particulado PM10 del día siguiente, que superen en Santiago de Chile la norma de calidad diaria. Una predicción adecuada de tales episodios permite a la autoridad decretar medidas restrictivas que aminoren la gravedad del episodio, y consecuentemente proteger la salud de la comunidad. Método: Se trabajó con las concentraciones de material particulado PM10 registradas en una estación asociada a la red de monitorización de la calidad del aire MACAM-2, considerando 152 observaciones diarias de 14 variables, y con información meteorológica registrada durante los años 2001 a 2004. Se ajustaron modelos estadísticos paramétricos Gamma usando el paquete estadístico STATA v11, y no paramétricos usando una demo del software estadístico MARS v 2.0 distribuida por Salford-Systems. Resultados: Ambos métodos de modelación presentan una alta correlación entre los valores observados y los predichos. Los modelos Gamma presentan mejores aciertos que MARS para las concentraciones de PM10 con valores <240µg/m³ para el año 2001, y los modelos MARS presentan mejores aciertos para aquellas que exceden los 240µg/m³ de PM10 para todos los años. Conclusiones: Los modelos MARS son más eficientes para predecir episodios graves de alta contaminación por PM10 y posibilitan a la autoridad sanitaria adoptar restricciones preventivas que aminoren su efecto sobre la salud de la población. Esto se explicaría porque MARS corrige las variaciones de la serie a lo largo del tiempo, ajustando mejor la curva asociada a la concentración de PM10.

Objective: To evaluate the predictive efficiency of two statistical models (one parametric and the other non-parametric) to predict critical episodes of air pollution exceeding daily air quality standards in Santiago, Chile by using the next day PM10 maximum 24h value. Accurate prediction of such episodes would allow restrictive measures to be applied by health authorities to reduce their seriousness and protect the community´s health. Methods: We used the PM10 concentrations registered by a station of the Air Quality Monitoring Network (152 daily observations of 14 variables) and meteorological information gathered from 2001 to 2004. To construct predictive models, we fitted a parametric Gamma model using STATA v11 software and a non-parametric MARS model by using a demo version of Salford-Systems. Results: Both models showed a high correlation between observed and predicted values. However, the Gamma model predicted PM10 values below 240µg/m³ more accurately than did MARS. The latter was more efficient in predicting PM10 values above 240µg/m³ throughout the study period. Conclusion: MARS models are more efficient in predicting extreme PM10 values and allow health authorities to adopt preventive methods to reduce the effects of these levels on the population´s health. The reason for this greater accuracy may be that MARS models correct variations in the series over time, thus better fitting the curve associated with PM10 concentrations.

Objetivo: Evaluar la eficiencia predictiva de modelos estadísticos paramétricos y no paramétricos para predecir episodios críticos de contaminación por material particulado PM10 del día siguiente, que superen en Santiago de Chile la norma de calidad diaria. Una predicción adecuada de tales episodios permite a la autoridad decretar medidas restrictivas que aminoren la gravedad del episodio, y consecuentemente proteger la salud de la comunidad. Método: Se trabajó con las concentraciones de material particulado PM10 registradas en una estación asociada a la red de monitorización de la calidad del aire MACAM-2, considerando 152 observaciones diarias de 14 variables, y con información meteorológica registrada durante los años 2001 a 2004. Se ajustaron modelos estadísticos paramétricos Gamma usando el paquete estadístico STATA v11, y no paramétricos usando una demo del software estadístico MARS v 2.0 distribuida por Salford-Systems. Resultados: Ambos métodos de modelación presentan una alta correlación entre los valores observados y los predichos. Los modelos Gamma presentan mejores aciertos que MARS para las concentraciones de PM10 con valores <240µg/m³ para el año 2001, y los modelos MARS presentan mejores aciertos para aquellas que exceden los 240µg/m³ de PM10 para todos los años. Conclusiones: Los modelos MARS son más eficientes para predecir episodios graves de alta contaminación por PM10 y posibilitan a la autoridad sanitaria adoptar restricciones preventivas que aminoren su efecto sobre la salud de la población. Esto se explicaría porque MARS corrige las variaciones de la serie a lo largo del tiempo, ajustando mejor la curva asociada a la concentración de PM10.