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SUMMARY OBJECTIVE: The aim of this study was to investigate the role of apparent diffusion coefficient of diffusion-weighted imaging in differentiating histological subtypes of brain metastasis of lung cancer. METHODS: Diffusion-weighted imaging of 158 patients (mean age: 61.2±10.68 years) with brain metastasis of lung cancer (36 small cell lung cancer and 122 non-small cell lung cancer) were retrospectively evaluated. The minimum and mean apparent diffusion coefficient values of the metastasis, apparent diffusion coefficient of edema around the metastasis, and apparent diffusion coefficient of contralateral brain parenchyma were measured. Normalized apparent diffusion coefficient was calculated by proportioning the mean apparent diffusion coefficient of the metastasis to the apparent diffusion coefficient of the contralateral brain parenchyma. Minimum and mean apparent diffusion coefficient of the metastasis, apparent diffusion coefficient of edema around metastasis, and normalized apparent diffusion coefficient were compared between small cell lung cancer and non-small cell lung cancer metastases. RESULTS: Minimum apparent diffusion coefficient, mean apparent diffusion coefficient, and normalized apparent diffusion coefficient values of small cell lung cancer metastases (0.43±0.19×10−3mm2/s, 0.63±0.20×10−3mm2/s, and 0.81 [0.55-1.44], respectively) were significantly lower than those of non-small cell lung cancer metastases (0.71±0.26×10−3mm2/s, 0.93±0.29×10−3mm2/s, and 1.30 [0.60-3.20], respectively; p<0.001). Mean apparent diffusion coefficient of edema of small cell lung cancer metastases (1.21±0.28×10−3mm2/s) was significantly lower than that of non-small cell lung cancer metastases (1.39±0.26×10−3mm2/s, p=0.020). The best cutoff values of minimum apparent diffusion coefficient, mean apparent diffusion coefficient, normalized apparent diffusion coefficient, and apparent diffusion coefficient of edema for the differentiation of small cell lung cancer and non-small cell lung cancer were found to be 0.56×10−3mm2/s, 0.82×10−3mm2/s, 1.085, and 1.21×10−3mm2/s, respectively. The area under the receiver operating characteristic curve, sensitivity, and specificity values were, respectively, 0.812, 80.6, and 73.8% for minimum apparent diffusion coefficient; 0.825, 91.7, and 61.5% for mean apparent diffusion coefficient; 0.845, 80.6, and 73.8% for normalized apparent diffusion coefficient; and 0.698, 75.0, and 67.7% for apparent diffusion coefficient of edema. CONCLUSIONS: Minimum apparent diffusion coefficient, mean apparent diffusion coefficient, normalized apparent diffusion coefficient, and apparent diffusion coefficient of edema around metastasis can differentiate histological subtypes of brain metastasis of lung cancer.
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Abstract Introduction: Otitis media, mastoiditis or the pressure effect of tumorous lesions such as cholesteatoma can be the cause of facial canal dehiscence and facial nerve paralysis. The most common segment involved in dehiscence is the tympanic segment and the second most common is the lateral aspect of the facial canal in the oval window area. Objective: To determine the prevalence of the facial canal dehiscence and the relationship between the angle at the second genu of the facial nerve and facial canal dehiscence. Methods: We evaluated the surgical findings in 113 patients who underwent surgery for cholesteatoma. Facial canal dehiscence was detected in 62 of the 113 patients. Patients were divided into two groups: Group 1, with dehiscence of the facial canal and Group 2, without dehiscence of the facial canal. Results: The mean angles at the second genu of the facial nerve in Groups 1 and 2 were 117.8º ± 9.63º and 114º ± 9.9º, respectively. There was a statistically significant difference between the mean angles at the second genu for the two groups (p = 0.04). Conclusion: In patients with dehiscence of the facial canal, the angle at the second genu was found to be wider than those without dehiscence.
Resumo Introdução: Otite média, mastoidite ou a compressão por lesões tumorais como o colesteatoma podem ser a causa da deiscência do canal facial e paralisia do nervo facial. A deiscência ocorre mais frequentemente no segmento timpânico, seguido do aspecto lateral do canal facial na área da janela oval. Objetivo: Determinar a prevalência da deiscência do canal facial e sua relação com o ângulo no segundo joelho do nervo facial. Método: Avaliamos os achados cirúrgicos para detecção de deiscência do canal facial em 113 pacientes submetidos à cirurgia de colesteatoma. A deiscência do canal facial foi observada em 62. Os pacientes foram divididos em dois grupos: Grupo 1, com deiscência do canal facial, e Grupo 2, sem deiscência do canal facial. Resultados: Os ângulos médios no segundo joelho do nervo facial nos grupos 1 e 2 foram 117,8º ± 9,63º e 114º ± 9,9º, respectivamente. Houve diferença estatisticamente significante entre os ângulos médios no segundo joelho para os dois grupos (p = 0,04). Conclusão: Em pacientes com deiscência no canal facial, foi observado que o ângulo do segundo joelho era maior do que naqueles sem deiscência.