肺癌および良性肺腫瘤のMRI所見と病理所見との関連

MRI and pathology of lung cancer and benign pulmonary nodule and mass

過去30年間にわたって，magnetic resonance imaging（MRI）の技術は劇的に発達してきているにもかかわらず，1991年のRadiologic Diagnostic Oncology GroupのWebbらの報告^1）以来，他部位の悪性腫瘍とは異なって，肺癌に対するMRIの適応は，胸壁浸潤や縦隔浸潤だけに限定されてきた。日本の肺癌診療ガイドライン2020年版^2）でも，肺腫瘍・結節の良悪性の鑑別におけるMRI検査のエビデンスの強さはC，推奨の強さは2と改善したばかりである。

Purpose：the aim of this study is to evaluate the relationships between DWI findings and pathologic findings of pulmonary nodules and masses. Methods：334 patients（282 resected lung cancers or 52 benign pulmonary nodules and masses：BPNM）were included. All MR images were performed using a 1.5 T magnetic scanner. Results：The mean ADC（1.23±0.29×10⁻³ mm²/sec）of lung cancer was significantly lower than that（1.69±0.58×10⁻³ mm²/sec）of BPNM. The ADC value of mucinous adenocarcinoma was significantly higher than that of each subclassification of adenocarcinoma. The ADC value of adenocarcinoma was significantly higher than that of squamous cell carcinoma, or small cell carcinoma. The ADC of lung cancer with necrosis was significantly lower than that of lung cancer without necrosis. Conclusions：MRI is a useful tool for clinical diagnosis and evaluation of lung cancer and BPNM. ADC shows higher values in mucinous lesions and lower values in necrotic lesions in lung cancers and BPNMs.