Nan Yu

Computed tomography quantification of pulmonary vessels in chronic obstructive pulmonary disease as identified by 3D automated approach.

AbstractThe aim of this study was to investigate the vascular alteration of the whole lung and individual lobes in patients with COPD, and assess the association between pulmonary vessels and the extent and distribution of emphysema as well as pulmonary function by a 3-dimensional automated approach.A total of 83 computed tomography images from COPD patients were analyzed. Automated computerized approach was used to measure the total number of vessels at the fifth generation. The extent of emphysema (%LAA-950) in the whole lung and individual lobes were also calculated automatically. The association between the vascular number and the extent and distribution of emphysema, as well as the pulmonary function were assessed.Both the vascular number of fifth generation in the upper lobe and in the lower lobe were significantly negatively correlated with %LAA-950 (P < 0.05). Furthermore, there were significant, yet weak correlations between the vascular number and FEV1% predicted (R = 0.556, P = 0.039) and FEV1/FVC (R = 0.538, P = 0.047). In contrast, the vascular numbers were strongly correlated with DLco (R = 0.770, P = 0.003). Finally, the vascular number correlated closer with %LAA-950 of upper lobes than with %LAA-950 of lower lobes.Pulmonary vessel alteration can be measured; it is related to the extent of emphysema rather than the distribution of emphysema.

Risk factors predict frequent hospitalization in patients with acute exacerbation of COPD

Purpose COPD is a heterogeneous disease, and the available prognostic indexes are therefore limited. This study aimed to identify the factors associated with acute exacerbation leading to hospitalization. Patients and methods This was a retrospective study of consecutive patients with COPD (meeting the Global Initiative for Chronic Obstructive Lung Disease [GOLD] diagnostic criteria) hospitalized at the Ninth Hospital of Xi’an Affiliated Hospital of Xi’an Jiaotong University between October 2014 and September 2016. During follow-up after first hospitalization, the patients who had been rehospitalized within 1 year for acute exacerbation were grouped into the frequent exacerbation (FE) group, while the others were grouped into the infrequent exacerbation (IE) group. The baseline demographic, clinical, laboratory, pulmonary function, and imaging data were compared between the two groups. Results Compared with the IE group, the FE group had lower forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) (P=0.005), FEV1%pred (P=0.002), maximal mid-expiratory flow (MMEF25–75%pred) (P=0.003), and ratio of carbon monoxide diffusion capacity to alveolar ventilation (DLCO/VA) (P=0.03) and higher resonant frequency (Fres; P=0.04). According to generations of bronchi, the percentage of the wall area (%WA) of lobes was found to be higher in the FE group. Emphysema index (EI), mean emphysema density (MED)whole and MEDleft lung in the FE group were significantly worse than in the IE group (P<0.05). Using logistic regression, exacerbation hospitalizations in the past year (odds ratio [OR] 14.4, 95% CI 6.1–34.0, P<0.001) and EI >10% (OR 2.9, 95% CI 1.2–7.1, P=0.02) were independently associated with frequent acute exacerbation of COPD (AECOPD) hospitalization. Conclusion Exacerbation hospitalizations in the past year and imaging features of emphysema (EI) were independently associated with FE hospitalization.

A three-dimensional approach for identifying small pulmonary vessels in smokers

BACKGROUND This study aims to develop a computerized scheme that utilizes a differential geometric approach to identify pulmonary vessels and then evaluate the performance of the scheme on the CT images of heavy smokers. METHODS The scheme consists of two primary steps to segment entire lung vascular tree and identify the number of pulmonary vessels in a cross section. The scheme performance including accuracy, consistency, and efficiency was assessed using 102 chest CT scans. Further assessment was performed on the relationship between pulmonary vessels and the extent of emphysema as well as pulmonary artery alteration. RESULTS The mean number of vessels in the cross section at the 5th generation was 17.84±4.74 and 17.23±4.85 assessed by computerized scheme and radiologists, respectively, which are significantly different (t = 2.12, p = 0.055). The results were consistent with those obtained by using a semi-automatic tool (r = 0.75, p = 0.01). In addition, in the 5th generation, the mean number of vessels was inversely related to the percentage of the low attenuation area (r = -0.704, p = 0.000), the mean lumen area of pulmonary vessel was inversely related to the mean value of main pulmonary artery diameter (r = -0.617, p = 0.000). The computational time of segmenting vessels was 6.50±0.02 seconds, which is much less than the average 8 minutes of the time spent by radiologists using the semi-automatic tool. CONCLUSION Applying the computerized scheme yields reasonable performance on the segmentation of pulmonary vessels. The alteration of pulmonary vessels may reflect the presence of pulmonary hypertension, as well as the extent of emphysema.

Sex-related differences in bronchial parameters and pulmonary function test results in patients with chronic obstructive pulmonary disease based on three-dimensional quantitative computed tomography

Objective This study was performed to evaluate the effect of sex on bronchial parameters and the predicted forced expiratory volume in 1 s expressed as a percentage of the forced vital capacity (FEV1% pred) on pulmonary function testing. Methods The data of 359 patients with chronic obstructive pulmonary disease (COPD) with available FEV1% pred and computed tomography (CT) images were retrospectively reviewed. FACT-Digital lung TM software (DeXin, Xi’an, China) was used to perform fully automated three-dimensional CT quantitative measurements of the bronchi. Generation 5 to 7 bronchi were measured, and the parameters analyzed were the lumen diameter (LD), wall thickness (WT), lumen area (LA), and WA% [WA / (WA + LA) × 100%]. Results In the smoking, smoking cessation, and nonsmoking groups, women had a significantly larger WA% and smaller LD, WT, and LA than men. The FEV1% pred was significantly lower in women than men in the smoking and smoking cessation groups. The FEV1% pred was significantly higher in women than men in the nonsmoking group. Conclusion Sex-related differences may partially explain why smoking women experience more severe pulmonary function impairment than men among patients with COPD.

Computer-aided detection for the automated evaluation of pulmonary embolism

BACKGROUND There are few quantitative studies that directly evaluate methods of determining pulmonary embolism (PE). New computer-aided detection (CAD) methods for measuring PE may help in defining the relationship of PE to right heart failure (RHF). OBJECTIVES We used CAD to investigate the severity of PE and explored whether the severity of PE was associated with RHF. METHODS A fully automatic calculation conducted by CAD was made of the embolism area/lumen area, which was used to evaluate the severity of the PE. The vascular obstruction index (VOI) was also used to evaluate PE, using the Mastora and Qanadli scores. Paired t tests were used to compare the severity of PE evaluated by Mastora or Qanadli score, to the severity determined by CAD. Correlation between the severity of the PE and RHF was also evaluated by Spearmans rank correlation analysis. RESULTS There was no significant difference between the PE evaluated by Mastora compared with the measurement by CAD (P= 0.720), and also no difference between evaluation by Qanadli and automatic measurement by CAD (P= 0.617). The severity of PE evaluated by Mastora, Qanadli, and CAD had significant positive correlation with RHF (R= 0.75 P= 0.01, R= 0.69 P= 0.02, R= 0.80 P= 0.00). CONCLUSION We found strong correlation between RHF and the severity of PE evaluated by CAD, and the method was found to be simple and reliable.

Combined subjective and quantitative analysis of magnetic resonance images could improve the diagnostic performance of deep myometrial invasion in endometrial cancer

PURPOSE To evaluate whether the combination of subjective magnetic resonance imaging (MRI) and quantitative analysis by using the exponential ADC (EADC) value of the peri-endometrial zone can improve the diagnostic performance of deep myometrial invasion in endometrial cancer patients. MATERIALS AND METHODS We prospectively evaluated 111 patients with either cervical cancer (normal endometria group) or endometrial cancer (endometrial cancer group). Two radiologists assessed all preoperative MR images with T1, T2, and diffusion-weighted imaging. The EADC value of the peri-endometrial zone was measured. Sensitivity, specificity, positive and negative predictive values, and the area under the receiver operating characteristic curve (Az) were calculated for Subjective MRI, an EADC cutoff value of the peri-endometrial zone and the combination of the two methods in assessing the prediction of deep myometrial invasion. RESULTS Specificity for EADC cutoff of the peri-endometrial zone was higher (0.93) than for Subjective MRI (0.80), as were the positive predictive values (EADC, 0.79; visual, 0.60). Sensitivity for the combined test was higher (0.88) than for Subjective MRI (0.71) and the EADC cutoff value (0.65), as were the negative predictive values (the combined test, 0.94; vs. EADC, 0.79; vs. Subjective MRI, 0.60). There were no differences in Az between the three methods (P>0.05), but the combined test had the highest Az. CONCLUSIONS Combined with conventional Subjective MRI, calculating EADC value of the peri-endometrial zone could improve the accuracy of preoperative assessment of deep myometrial invasion in endometrial cancer patients, and maybe helpful in tailoring a surgical approach for intervention.