Assessing Tumor Perfusion, Treatment Response And Prognosis In Lung Cancer With Multislice Perfusion CT

PURPOSE: The first purpose is to prospectively investigate tumor perfusion characteristics and the utility of Perfusion CT in lung cancer, and to determine whether any of the perfusion parameters would predict early tumor response to chemotherapy and/or radiotherapy. The second purpose is to compare the perfusion parameters of lung cancer before and after chemotherapy and/or radiotherapy and to investigate whether any of the perfusion parameters would predict the prognosis.MATERIALS AND METHODS: In a prospective series, Perfusion CT were performed in 152 patients suspected lung cancer with GE LightSpeed Pro or GE LightSpeed Ultra multislice CT. Contrast medium (50 ml) was injected at a rate of 4 ml/sec with a power injector. The scanning delay was 10 seconds and the scanning time was 50 seconds. Among 152 patients, 123 patients were proved lung cancer by pathology. The perfusion image quality was evaluated on a 4-1eveal scale. In 84 patients (median age, 59 years; 70 men, 14 women), the perfusion image quality was graded as moderate or good. With the Perfusion 3.0 software, the parameters including blood flow (BF), blood volume (BV), mean transit time (MTT) and capillary permeability surface area product (PS) were calculated. Measurement reproducibility was assessed using Bland-Altman statistics. In 35 patients with NSCLC after chemotherapy and/or radiotherapy and assessed with RECIST, the relationship between perfusion parameters with early tumor response to chemotherapy and/or radiotherapy was evaluated. In 24 patients, the perfusion parameters of lung cancer before and after chemotherapy and/or radiotherapy were compared, and the relationship between perfusion parameters with progression-free survival and overall survival was also assessed.RESULTS: In 31.8% patients, the perfusion image quality was staged level 0 (failed) and level 1 (poor). In 68.2% patients, the perfusion image quality was staged level 2 (moderate) and level 3 (good). High interobserver and introobserver correlations of perfusion parameters were found in tumors and muscles. In 84 patients, the mean BF of tumors and muscles was 70.8 ml/min/100g±29.7 and 15.8 ml/min/100g±19.1 respectively; the mean BV was 5.4 ml/100g±1.7 and 1.3ml/100g±0.7 respectively; the mean MTT was 8.5 s±3.8 and 14.9 s±8.1 respectively; the mean PS was 14.6 ml/min/100g±5.8 and 3.6 ml/min/100g. All of them were significantly different. The largest dimension of tumor (≤50mm,＞50ram) had not impact on perfusion parameters. BV in central and peripheral carcinomas was significantly different; the other parameters in central and peripheral carcinomas were not significantly different. Among NSCLC (squamous cell carcinoma and adenocarcinoma) and SCLC, no significant differences were observed in all parameters. The parameters of different differentiated and staged carcinomas were also not significantly different. Linear regression analysis revealed that sex, age and weight had no influence on perfusion parameters. In 35 patients with NSCLC, BF and BV in the response group were significantly higher than that in the nonresponse group.The median PFS of low-BF group (BF≤80ml/min/100g) and high-BF group (BF＞80ml/min/100g) was 11.8 months and 8.0 months respectively, and the median OS of low-BF group and high-BF group was 14.3 months and 11.6 months respectively, both of them were not significantly different. The median PFS of low-BV group (BF≤6ml/100g) and high-BV group (BF＞6ml/100g) was 9.2 months and 8.0 months respectively, and the median OS of low-BV group and high-BV group was 13.9 months and 16.1 months respectively, both of them were not significantly different. In 24 patients, the perfusion parameters were compared before and after chemotherapy and/or radiotherapy. All the patients were divided two groups according to PS. In increased PS group (n=13), PS was significantly higher after than before treatment (20.1±7.5ml/min/lOOg VS 13.7±6.2ml/min/100g, t=2.941, p=0.013), but no significant differences observed in BF, BV, and MTT. In decreased PS group (n=11), PS was significantly lower after than before treatment (8.2±5.5ml/min/100g VS 15.3±5.1ml/min/100g, t=5.586, p=0.000), but no significant differences observed in BF, BV, and MTT. The median PFS of increasing group and decreasing group was 4.2 months and 19.0 months respectively (Log Rank=24.93, p=0.000), and the median OS was 7.9 months and 19.3 months respectively (Log Rank=9.90, p＝0.002). Both of them were significantly different.CONCLUSION: Perfusion parameters of tumors and muscles are reproducible, but the image quality of perfusion maps is not very satisfied in some patients. BF, BV, and PS of tumors are higher than that of muscles, and MTT of tumors are lower than that of muscles. Sex, age and weight had no influence on perfusion parameters. The parameters of different dimension, position, pathology, differentiation and staging carcinomas were not different. Non-small cell lung cancers in high perfusion are relatively sensitive to chemotherapy and/or radiotherapy, and the response rate is relatively higher, but the progress time is relatively shorter. Among the perfusion parameters, PS is probable the most helpful parameter for predicting the prognosis of lung cancer.