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ABSTRACT: Objective: To investigate the correlation between the biphasic mean lung density (MLD) measured by a computer-aided method and the pulmonary function test (PFT) in patients with chronic obstructive pulmonary disease (COPD). Methods: Sixty COPD patients diagnosed in The Affiliated Hospital of Yan'an University from June 2017 to June 2018 were retrospectively recruited. CT scans at the end of inspiratory phase and the end of expiratory phase were performed. MLD of the whole lung and individual lobes were measured by a three-dimensional method, and PFT was performed within one week. The correlation between MLD and PFT was analyzed. Results: We found a slight positive correlation between MLDin and PFT of the whole lung and each lung lobe (P<0.05). MLDex, MLDex-MLDin of the whole lung and each lung lobe showed moderate to high positive correlation with PFT (P<0.01), and MLDex/in of the whole lung and each lung lobe showed moderate to high negtive correlation with PFT (P<0.01). Conclusion: Quantitative measurement of mean lung density in COPD patients is correlated with lung function and MLDex/in of the whole lung shows the highest correlation.
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OBJECTIVE: To investigate the correlation between non-alcoholic fatty liver disease and visceral adipose tissue in non-obese Chinese adults using computed tomography (CT). MATERIALS AND METHODS: The study included 454 subjects undergoing abdominal CT scan. Degree of CT attenuation in liver and spleen, and the degree of fat infiltration in liver were evaluated according to three indices: the attenuation value of liver parenchyma (CTLP), the attenuation ratio of liver and spleen (LSratio) and the attenuation difference between liver and spleen (LSdif). Visceral fat area (VFA) and total fat area (TFA) at L2/3 and L4/5 levels were measured, and the abdominal subcutaneous fat area (SFA) was calculated. Bivariate correlation analysis was carried out to determine the correlation among these factors. RESULTS: In men, VFA, SFA and TFA at L2/3 and L4/5 levels showed significant differences in terms of the three indices to distinguish fatty liver from non-fatty liver (all, p < 0.001). In men, all the three indices showed negative correlation with TFA, SFA and VFA (all, p < 0.001). The negative correlation between the three indices and VFA at the L2/3 level was higher than at L4/5 level (r = −0.476 vs. r = −0.340 for CTLP, r = −0.502 vs. r = −0.413 for LSratio, r = −0.543 vs. r = −0.422 for LSdif, p < 0.001, respectively). The negative correlation between LSratio, LSdif and VFA at L2/3 and L4/5 levels was higher than SFA at the corresponding level. In women, all the three indices showed negative correlation with VFA and TFA at L2/3 and L4/5 levels, and the negative correlation between CTLP and VFA was higher at L2/3 level than at L4/5 level (r = −0.294 vs. r = −0.254, p < 0.001). CONCLUSION: In non-obese Chinese adults, the degree of hepatic fatty infiltration showed a strong correlation with abdominal fat on CT. VFA at L2/3 level was more closely related to fatty liver compared with VFA at L4/5 level.