The purpose of our study is to determine whether contrast-enhanced dynamic MRI (DCE MRI) analysis of tumor angiogenesis and perfusion can be used as a reliable modality to differentiate benign from malignant solitary pulmonary nodules (SPN) before surgical intervention, using kinetic model derived from DCE MRI, and further correlate if there is any positive correlation between angiogenesis factor (vascular endothelial growth factor VEGF, microvessel density MVD); and if the perfusion parameters from DCE MRI can predict patients' outcomes and survival.

The solitary pulmonary nodule (SPN) is a common finding in chest radiography. Pulmonary nodules larger than 1cm indicative of malignancy or with indeterminate finding according to morphology criteria have to be defined by invasive methods such as biopsy or surgical excision, and benign pathology makes up 20-50% of those resected pulmonary lesions. The lesions not receiving surgical intervention often need imaging follow-up on a regular basis for a long period of time to monitor the stability of the finding.

There are many reports regarding the MRI perfusion analysis of neoplasms from many organs, including bone marrow, liver, breast, cervix, and they stressed not only on comparison between benignity and malignancy, but also on monitoring the treatment outcomes after neoadjuvant chemotherapy, radiation therapy or anti-angiogenic agent therapy [7-15]. Dynamic contrast-enhanced MRI (DCE MRI) is not a standard examination for SPN, but there have been some data regarding the differentiation between malignant and benign SPN using DCE MRI, with MRI offering higher specificity compared to dynamic CT scan [6, 7, 16]. It was also reported that DCE MRI could delineate kinetic and morphologic differences in tumor angiogenesis and perfusion characteristics between malignant and benign pulmonary lesions with relatively high accuracy [7, 16]. The purpose of our study is to determine whether DCE MRI analysis of tumor angiogenesis and perfusion can be used as a reliable modality to differentiate benign from malignant SPN before surgical intervention, using kinetic model derived from DCE MRI, and further correlate if there is any positive correlation between angiogenesis factor (vascular endothelial growth factor VEGF, microvessel density MVD); and if the perfusion parameters from DCE MRI can predict patients' outcomes and survival.

Inclusion Criteria:

• patients who have solitary pulmonary nodules in CT

Exclusion Criteria:

• patients who don't fit the above inclusion criteria