Diffusion-weighted magnetic resonance imaging is useful for the response evaluation of chemotherapy and/or radiotherapy to recurrent lesions of lung cancer.

Diffusion-weighted magnetic resonance imaging (DWI) has been reported to be useful for the assessment of lung cancer staging. It is uncertain whether DWI is more accurate for the response evaluation of chemotherapy and/or radiotherapy compared to computed tomography (CT). The purpose of this study is to compare the response evaluation of DWI for chemotherapy and/or radiotherapy to recurrent tumors of lung cancer with that of CT which is a standard tool in RECIST (Response Evaluation Criteria in Solid Tumours). Forty-one patients who agreed to this project and had CT scan and DWI examinations within a month of each other every six months for at least 2 years after pulmonary resection of primary lung cancer were enrolled in this study. Of the patients, 24 patients had metastases or recurrences, and CT and DWI were performed for assessment of the response evaluation of chemotherapy and/or radiotherapy to recurrent lesions. They were followed up for at least two years after the relapse. The response evaluation by CT using RECIST were PR in five patients, SD in two, and PD in the remaining 17 patients. On the other hand, the response evaluation by DWI were CR in four patients, PR in two patients, SD in one, and PD in the remaining 17 patients. Follow-up studies revealed the response evaluation by DWI were correct. Functional evaluation of DWI is better than that of CT for the response evaluation of chemotherapy and/or radiotherapy to recurrent tumors of lung cancer.