血液疾患に対するMRIの有用性 : 脂肪抑制画像及び造影剤の併用 <原著>

Recently, some studies of bone marrow diseases using the MRI had been reported. However there was no report with the combination method of the fat-suppression and the contrast medium, and there were few reports about bone marrow other than the vertebral bodies. In this study, I evaluated the MR imaging of the bone marrow with the combination method of the fat-suppression and the contrast enhancement. A 1.5 Tesla superconducting MRI system was used in this investigation. In 9 adult patients their vertebral bodies, pelvic bones, and femurs were examined. The MRI images were analyzed qualitatively. The results were as follows : 1) The foci of the adult bone marrow diseases demonstrated low signal intensity on both of T1WI and T2WI with a rate of 23/27 and 20/27,respectively. 2) Among three patients with AML (acute myelocytic leukemia), only one case showed normal MRI appearances during the follow up period with only blood transfusion. 3) The patients with ALL (acute lymphocytic leukemia) demonstrated hypointensity on both of T1WI and T2WI of the bone marrow, but had no contrast enhancement. 4) The patients with CML (chronic myelocytic leukemia) demonstrated hypointensity on both of T1WI and T2WI of the bone marrow, but had contrast enhancement. 5) The T1WI of bone marrow with myelofibrosis displayed diffuse hypointensity while they showed a slight enhancement on the fat-suppressed enhancement MRI. One of the two cases demonstraed high intensity on the T2WI. 6) In patients of MDS (myelodysplastic syndrome), the MRI of the vertebral and pelvic bone marrow demonstrated low intensity on both of the T1WI and T2WI and had a contrast enhancement. However, in the femors heads, the T1WI and T2WI normal intensity but fat-marrow showed no contrast enhancement. The results of this study indicated that changes of MRI signal intensity in bone marrow might be a clinical index to evaluate the effectiveness of therapy for the patient of bone marrow diseases.

近年, 磁気共鳴画像(Magnetic Resonance Imaging, MRI)を用いた骨髄病変の研究が散見されるようになったが, 脂肪抑制(Fat Sat)及び造影剤を併用した報告は無く, また脊椎以外の骨髄について検討した報告は少ない。今回筆者は, Fat Sat法と造影剤を併用して撮像された骨髄のMRIについて評価を行った。1.5テスラ超伝導装置を用いて9例の成人患者の脊椎, 腸骨, 大腿骨の検査を行い, MR画像を定性的に解析した。結果は以下の通りである。1.成人の骨髄病変はT1強調画像(T1WI), T2強調画像(T2WI)ともにそれぞれ23/27,20/27の確率で低信号を示した。2.3例の急性骨髄性白血病(acute myelocytic leukemia, AML)患者のうち, 輸血のみで経過観察されている1例のみ正常MRI像を示した。3.急性リンパ性白血病(acute lymphocytic leukemia, ALL)患者は骨髄のT1WI, T2WIともに低信号を示したが, 造影効果は認められなかった。4.慢性骨髄性白血病(chronic myelocytic leukemia, CML)患者は骨髄のT1WI, T2WIともに低信号を示したが, 造影効果は認められた。5.骨髄線維症(myelofibrosis, MF)患者の骨髄はT1WIにおいてび慢性の低信号を示し, Fat Sat造影MRIにて軽度の造影効果を示した。2例中1例はT2WIにて高信号を示した。6.骨髄異形成症候群(myelodysplastic syndrome, MDS)患者においては脊椎と腸骨の骨髄はT1WI, T2WIともに低信号を示し, 造影効果が認められたが, 大腿骨骨髄はT1WI, T2WIともに正常信号を示し, 脂肪髄造影効果は認められなかった。本研究の結果は, 骨髄におけるMRIの信号変化が, 血液疾患に対する治療の有効性を評価する指標となりうることを示唆するものである。