Application Of SWI In Evaluating The Response Of Brain Matastases From Lung Cancer Treated By Radiotherapy

Objective To evaluate the value of 3.0T MRI Susceptibility-weighted-imaging sequence in evaluating the response of brain matastases treated by radiotherapy from compare the changes of the number of tumor angiogenesis in brain metastases before and after radiotherapy determinated by SWI.Meterials and Methods Complete imaging data of twenty-four cases of brain metastases were confirmed by clinical or pathology in our hospital and received radiotherapy,including conventional MR scanning, contrast enhanced T1 and SWI scanning before and after radiotherapy. All conventional MR image and SWI image were reviewed independently by two neuroradiolodists. Comparative analysis of measured data before and after treatment and correlation analysis of changes of the number of blood vessels and the volume change of tumors.Results1. Types of lung cancer of the 24 Patients with brain metastases including 14 cases(58%)of Adenocarcinoma,3 cases(12.5%)of squamous cell carcinoma,7 cases(29.5%)of small cell carcinoma.They were all parenchyma metastasis brain.Among them, 8 cases(33.3%) of single focus and 16 cases(66.7%) of multiple foci. More lesions were seen on enhanced T1WI(n=221) and SWI(n=222) than those on the precontrast MRI(n=146),The numbers of tumor with hemorrhage on SWI(n=113) were significantly more than those on conventional MRI(n=35).2. 126 lesions were included in the efficacy study, tumor angiogenesis and minimal hemorrhage within the tumor can be detected before radiotherapy by SWI,the follow up MRI studies of the 126 lesions after completion of therapy showed vessel density decreased in SWI image and decrease in tumor volume.Conclusion1. SWI showed high sensitivity to detect the brain metastasis, and it has certain advantages in detecting intratumoral small vessels and micro-hemorrhage in brain metastasis from lung cancer. SWI can provide more imaging information than conventional MRI in the diagnosis of brain metastases from lung cancer.2. There was correlation between changes of the number of blood vessels and the volume change of tumors before and after radiotherapy.3. SWI was able to detect the changes of the number of tumor angiogenesis in brain metastases before and after radiotherapy, in order to evaluate the efficacy of radiotherapy for brain metastases and provides effective evidences of constitution for more clinical therapy projects.