Rhinomanometry using computational fluid dynamics

Introdução: A obstrução nasal é um sintoma presente em várias doenças nasais. Este projeto propõe desenvolver uma metodologia para o cálculo da resistência nasal ao fluxo aerífero por meio de fluidodinâmica computacional e comparar os resultados dessa técnica com os da rinomanometria. Métodos: a resistência nasal ao fluxo aerífero foi medida por rinomanometria, experimentalmente e por fluidodinâmica computacional. A influência da segmentação da tomografia computadorizada nas variáveis de fluidodinâmica computacional foi investigada. O modelo computacional de escoamento laminar foi comparado ao modelo de turbulência k-w padrão. Foram analisadas a acurácia, correlação e concordância entre a resistência nasal calculada por fluidodinâmica computacional com aquela obtida por experimento e rinomanometria. Resultados: A resistência nasal provida por fluidodinâmica computacional pode variar até 50% de acordo com os critérios de segmentação da tomografia computadorizada. O modelo de turbulência k-w padrão apresentou acurácia de 93,1%, demonstrando melhor desempenho que o modelo laminar para prever a resistência da cavidade nasal. A correlação entre a vazão em 75Pa obtida por rinomanometria e fluidodinâmica computacional foi alta para ambas as cavidades, Pearson r = 0,75 p = 0.75 p < 0.001. There was no agreement between nasal resistance provided by the two methods. Nasal resistance due to computational fluid dynamics is, on average, 65% of rhinomanometric resistance. Conclusion: the criteria used for nasal cavity segmentation interfere with the resistance calculated by computational fluid dynamics. The methodology of computational fluid dynamics to calculate nasal resistance was validated experimentally. The turbulent flow model is better than the laminar model to calculate nasal resistance. The nasal resistance calculated by computational fluid dynamics showed a high correlation with the measurement by active rhinomanometry, but the level of agreement between the methods does not allow a direct comparison between the values obtained by each on

Rhinomanometry using computational fluid dynamics

Introdução: A obstrução nasal é um sintoma presente em várias doenças nasais. Este projeto propõe desenvolver uma metodologia para o cálculo da resistência nasal ao fluxo aerífero por meio de fluidodinâmica computacional e comparar os resultados dessa técnica com os da rinomanometria. Métodos: a resistência nasal ao fluxo aerífero foi medida por rinomanometria, experimentalmente e por fluidodinâmica computacional. A influência da segmentação da tomografia computadorizada nas variáveis de fluidodinâmica computacional foi investigada. O modelo computacional de escoamento laminar foi comparado ao modelo de turbulência k-w padrão. Foram analisadas a acurácia, correlação e concordância entre a resistência nasal calculada por fluidodinâmica computacional com aquela obtida por experimento e rinomanometria. Resultados: A resistência nasal provida por fluidodinâmica computacional pode variar até 50% de acordo com os critérios de segmentação da tomografia computadorizada. O modelo de turbulência k-w padrão apresentou acurácia de 93,1%, demonstrando melhor desempenho que o modelo laminar para prever a resistência da cavidade nasal. A correlação entre a vazão em 75Pa obtida por rinomanometria e fluidodinâmica computacional foi alta para ambas as cavidades, Pearson r = 0,75 p = 0.75 p < 0.001. There was no agreement between nasal resistance provided by the two methods. Nasal resistance due to computational fluid dynamics is, on average, 65% of rhinomanometric resistance. Conclusion: the criteria used for nasal cavity segmentation interfere with the resistance calculated by computational fluid dynamics. The methodology of computational fluid dynamics to calculate nasal resistance was validated experimentally. The turbulent flow model is better than the laminar model to calculate nasal resistance. The nasal resistance calculated by computational fluid dynamics showed a high correlation with the measurement by active rhinomanometry, but the level of agreement between the methods does not allow a direct comparison between the values obtained by each on

Prevalence of respiratory epithelial adenomatoid hamartomas (REAH) associated with nasal polyposis: an epidemiological study – how to diagnose

Objectives: To highlight the prevalence of respiratory epithelial adenomatoid hamartomas in the olfactory cleft of patients with nasal polyposis. To demonstrate characteristics indicative of hamartoma on the CT scans of paranasal sinuses during surgery and in histopathological exams. Methods: Cross-sectional study carried out in Hospital das Clínicas da UFMG and Núcleo de Otorrino BH. We performed 114 nasal endoscopic surgeries for polyposis, between February 2015 and November 2019. We assessed the olfactory cleft width in all preoperative CT scans. Upon seeing an indication of hamartoma on the CT scan, we took a tissue sample from the olfactory cleft during the surgery and sent for histopathological exam. We referred the samples to a pathologist experienced in the anatomopathological diagnosis of respiratory epithelial adenomatoid hamartomas. Results: Of the 114 patients with polyposis, 54 (47.4%) had olfactory cleft enlargement and, 100% of them had tissue with a dense and hardened polypoid aspect, with a slight cerebriform appearance in this region during the surgery. Histology confirmed a respiratory epithelial adenomatoid hamartoma. Conclusion: This observation suggests that the presence of hamartomas in polyposis is common, but underdiagnosed. Level of evidence: Step 3 (Level 3)

Explaining changes in rainfall-runoff relationships during and after Australia's Millennium Drought : a community perspective

The Millennium Drought lasted more than a decade and is notable for causing persistent shifts in the relationship between rainfall and runoff in many southeastern Australian catchments. Research to date has successfully characterised where and when shifts occurred and explored relationships with potential drivers, but a convincing physical explanation for observed changes in catchment behaviour is still lacking. Originating from a large multi-disciplinary workshop, this paper presents and evaluates a range of hypothesised process explanations of flow response to the Millennium Drought. The hypotheses consider climatic forcing, vegetation, soil moisture dynamics, groundwater, and anthropogenic influence. The hypotheses are assessed against evidence both temporally (e.g. why was the Millennium Drought different to previous droughts?) and spatially (e.g. why did rainfall-runoff relationships shift in some catchments but not in others?). Thus, the strength of this work is a large-scale assessment of hydrologic changes and potential drivers. Of 24 hypotheses, 3 are considered plausible, 10 are considered inconsistent with evidence, and 11 are in a category in between, whereby they are plausible yet with reservations (e.g. applicable in some catchments but not others). The results point to the unprecedented length of the drought as the primary climatic driver, paired with interrelated groundwater processes, including declines in groundwater storage, altered recharge associated with vadose zone expansion, and reduced connection between subsurface and surface water processes. Other causes include increased evaporative demand and harvesting of runoff by small private dams. Finally, we discuss the need for long-term field monitoring, particularly targeting internal catchment processes and subsurface dynamics. We recommend continued investment in the understanding of hydrological shifts, particularly given their relevance to water planning under climate variability and change