肝細胞癌画像診断におけるMRI拡散強調画像の有用性  [in Japanese] Usefulness of diffusion-weighted MR imaging for imaging diagnosis of hepatocellular carcinoma  [in Japanese]

MRI拡散強調画像の画像診断能について，動脈性血流に富む肝細胞癌52例で造影CT所見との比較をレトロスペクティブに検討した．肝動脈塞栓術目的に行った血管造影下CTにおけるCTHAでの早期濃染とCTAPでの還流低下を示した170病変をゴールドスタンダードとして対比した結果，腫瘍の検出感度はMRI拡散強調画像が78.2%，造影CTが80.0%と同等であり，ともに腫瘍多発例より単発例で良好であった．各症例での検出腫瘍数は両者同等が65.3%で，MRI拡散強調画像優位が13.5%であったのに対して造影CT優位が21.2%であったが，有意差はなかった．肝細胞癌治療歴の有無での検討でも有意差はなかったが，とくに治療歴を有する症例ではMRI拡散強調画像優位が20.8%であった．動脈性血流の増加を伴う肝細胞癌患者において，MRI拡散強調画像は造影剤を必要とせず，また放射線被曝のない画像検査として有用と考えられた．

We retrospectively evaluated the detectability of hypervascular hepatocellular carcinoma (HCC) on diffusion-weighted MR imaging (DWI) in 52 patients, and compared that on contrast-enhanced CT (enhanced CT). One hundred and seventy tumor lesions, showing hypervascular tumor on CT during hepatic arteriography and hypoperfusion area on CT dyring arterial portography prior to achievement of transcatheter arterial chemoembolization, were referred as the gold standard for the comparison of DWI with enhanced CT. Sensitivity for the detection of tumors was 78.2% on DWI and 80.0% on enhanced CT. The detected number of tumors in each patient was equal in 65.3% of them on both modalities and superior in 13.5% of them on DWI without significant difference. The superiority of DWI to enhanced CT in the patients with previous treatment was shown in 20.8% of patients. We suggest that DWI could be useful modality for the detection of hypervascular HCC without using contrast agent and radiation exposure.