大野 良治

【背景】血液疾患では長期輸血等で鉄過剰となる。肝鉄量は鉄過剰の重要な指標であり、欧米では MRI によ る非侵襲的定量法が普及しつつあるが、日本では殆ど行われていない。【方法】Gandon らの論文に基づき、腹部 MRI をグラディエントエコー法(GRE)で撮影、肝臓(L)と脊筋(M)の信号強度比(LBackground: Iron overload is a major problem for patients with hematological diseases. Liver iron concentration (LIC) is an important marker of iron overload. LIC has been measured by MRI (Magnetic Resonance Imaging) instead of invasive hepatic biopsy in European countries, but not yet in Japan. Methods: LIC was measured by MRI according to Gandon's method (Lancet 2004;363:357-362) using gradient echo sequence (GRE). Signal intensity ratio of the liver and muscle (L/M) was measured. LIC was estimated from the linear correlation curve of L/M and LIC shown in Gandon's paper. LIC estimated from MRI (LIC-MRI) was compared with serological markers such as serum ferritin level. Patients:Three patients with hematological diseases (post-transfusion iron overload, chronic hemolytic anemia, secondary myelofibrosis) and three healthy persons as normal controls. Results: LIC-MRI and serological markers were normal among the three normal controls. Two patients showed ten times higher LIC-MRI and ferritin levels than normal ranges. Conclusion: LIC-MRI showed an excellent correlation with serum ferritin level. Because of low examination numbers for the present cases, further study is necessary.