Lihua Zhang1, Yunhua Wang. 1. Center of PET-CT, Second Xiangya Hospital, Central South University, Changsha 410011, China.
Abstract
OBJECTIVE: To explore the value of 64 slice spiral CT (SCT) low-dose chest scanning at full inspiration and full expiration for lung density measurement in assessing the pulmonary function in patients with chronic obstructive pulmonary disease (COPD). METHODS: Totally 36 COPD patients (the COPD group) underwent pulmonary function tests (PFT) and were essentially verified COPD; 30 healthy people (the control group) were selected whose 64 slice SCT chest scanning was normal. The 2 groups underwent chest 64 slice SCT low-dose scanning at full inspiration and full expiration. After the scanning, the lung was measured by CT Pulmo software. The lung was divided into 3 regions by scanning layers. We measured and calculated the density indexes of each region (including the upper, middle, lower field, and the total lung) of the 2 groups. All density indexes were lung density at full inspiration and full expiration (Din, Dex), density difference (Dex-Din), density ratio (Dex/ Din), density variation percentage (Din-Dex)/Din. All patients underwent PFT and 64 slice SCT within 3 days, whose pulmonary function was tested by Master Lab ( Jaeger, Germany). The indexes were the percentage of actual value and expected value of forced expiratory volume at the first second (FEV1%) and the ratio of first second forced expiratory volume to forced vital capacity (FEV1/FVC). Then we compared with the CT indexes between the COPD group and the control group. The relevant indicators of lung densities were analyzed in comparison with the indicators of FEV1% and FEV1/FVC by Pearson correlation analysis. RESULTS: The density indexes of each region and total lung, and the Din in the control group and the COPD group were compared. The difference between them was statistically significant (P<0.05). The difference among other indexes was also statistically significant (P<0.01). Excellent correlation was found between Dex, Dex-Din, Dex/ Din and (Din-Dex)/ Din indexes with FEV1% and FEV1/FVC (r=0.566, 0.686, 0.568, 0.580, -0.565, -0.598, 0.565 and 0.598; P<0.01) CONCLUSION: Sixty-four slice SCT low-dose two-phase scanning density indexes are closely related to the indicators (FEV1% and FEV1/FVC) of clinical lung function tests, which can be used to evaluate the lung function in COPD patients conventiently and accurately.
OBJECTIVE: To explore the value of 64 slice spiral CT (SCT) low-dose chest scanning at full inspiration and full expiration for lung density measurement in assessing the pulmonary function in patients with chronic obstructive pulmonary disease (COPD). METHODS: Totally 36 COPD patients (the COPD group) underwent pulmonary function tests (PFT) and were essentially verified COPD; 30 healthy people (the control group) were selected whose 64 slice SCT chest scanning was normal. The 2 groups underwent chest 64 slice SCT low-dose scanning at full inspiration and full expiration. After the scanning, the lung was measured by CT Pulmo software. The lung was divided into 3 regions by scanning layers. We measured and calculated the density indexes of each region (including the upper, middle, lower field, and the total lung) of the 2 groups. All density indexes were lung density at full inspiration and full expiration (Din, Dex), density difference (Dex-Din), density ratio (Dex/ Din), density variation percentage (Din-Dex)/Din. All patients underwent PFT and 64 slice SCT within 3 days, whose pulmonary function was tested by Master Lab ( Jaeger, Germany). The indexes were the percentage of actual value and expected value of forced expiratory volume at the first second (FEV1%) and the ratio of first second forced expiratory volume to forced vital capacity (FEV1/FVC). Then we compared with the CT indexes between the COPD group and the control group. The relevant indicators of lung densities were analyzed in comparison with the indicators of FEV1% and FEV1/FVC by Pearson correlation analysis. RESULTS: The density indexes of each region and total lung, and the Din in the control group and the COPD group were compared. The difference between them was statistically significant (P<0.05). The difference among other indexes was also statistically significant (P<0.01). Excellent correlation was found between Dex, Dex-Din, Dex/ Din and (Din-Dex)/ Din indexes with FEV1% and FEV1/FVC (r=0.566, 0.686, 0.568, 0.580, -0.565, -0.598, 0.565 and 0.598; P<0.01) CONCLUSION: Sixty-four slice SCT low-dose two-phase scanning density indexes are closely related to the indicators (FEV1% and FEV1/FVC) of clinical lung function tests, which can be used to evaluate the lung function in COPD patients conventiently and accurately.