Usefulness of the MRI for the response evaluation of chemotherapy /radiotherapy of lung cancer (Fig. 28, 29).
Although CT is used for the response evaluation of chemotherapy /radiotherapy of lung cancer, the response evaluation is based on the lesion size. In the situation sometimes the real lesion may be unknown. Even in the situation, the qualitative diagnosis of the lesion is possible using ADC in MRI (DWI). 
Fig. 28 Usefullness of MRI (DWI) for response evaluation of chemoradiotherapy after lung cancer recurrence. Local recurrence on #4R lymph node after right upper lobectomy of lung cancer (Adenocarcinoma, pStage IB) Usuda K, et al. Transl Oncol. 2019;12(5):699-704.
Fig. 29 Response evaluation after chemoradiotherapy
PR by CT, CR by MRI (DWI) Although CT showed PR, MRI (DWI) showed CR. PET-CT showed no accumulation of FDG. Follow-up study showed CR.
Usuda K, et al. Diffusion-weighted magnetic resonance imaging is useful for the response evaluation of chemotherapy and/or radiotherapy to recurrent lesions of lung cancer. Transl Oncol. 2019;12(5):699-704.
Ciliberto M, et al. Comparison between whole-body MRI and Fluorine-18 fluorodeoxyglucose PET or PET/CT in oncology: a systematic review. Radiol Oncol 2013; 47 (3): 206–218.
