たこつぼ型心筋障害における心臓MRI所見

Delayed-contrast Gd-DTPA Enhanced Cardiac Magnetic Resonance in Takotsubo Cardiomyopathy

要旨　たこつぼ型心筋障害とは急性心筋梗塞に類似した心電図変化を有しながら，それに伴う左室壁運動異常が一つの冠動脈の支配領域を超えて広く存在し，左室造影上あたかも“たこつぼ”を思わせる形態を有する疾患である．しかし，この疾患の心臓MRI所見は報告により様々であり未だ明らかではない．今回われわれは，亜急性期と慢性期に心筋SPECTおよび心臓MRIを施行しえた3症例を経験した．症例はすべて高齢女性で，精神的ストレスを有していた．冠動脈造影では有意狭窄を認めなかった．心筋SPECTにおいて，亜急性期には壁運動異常部位に一致して灌流低下が認められ，慢性期に灌流は回復した．Gd-DTPA遅延造影心臓MRIにおいて，亜急性期には壁運動異常部位を中心に全層性に淡い高信号を認めた．慢性期には，遅延造影での淡い高信号は徐々に消褪傾向を示した．このMRI所見はたこつぼ型心筋障害の病理学的な変化を反映していると考えられ，文献的考察を加え報告する．

　Takotsubo cardiomyopathy is a condition that mimics acute coronary syndrome without typical coronary angiographic stenosis. It remains unknown whether delayed enhancement(DE) was present or not and which type of DE was observed in patients of Takotsubo cardiomyopathy. We reported three cases of Takotsubo cardiomyopathy that could be evaluated with rest Tc-MIBI SPECT and cardiac magnetic resonance(CMR) in the subacute and chronic phases. All patients were women and suffered from psychological stress. In none of the cases was significant epicardial stenosis documented in any of the acute-phase coronary angiograms. Left ventriculography revealed akinesia or dyskinesia of the mid and/or apical portion of the LV chamber compared with hyper-contraction of the basal LV. Rest Tc-MIBI SPECT in the sub-acute phase showed perfusion defect at the area of wall motion impairment. Delayed Gd-DTPA enhanced CMR in the subacute phase demonstrated diffuse smoky DE in the area matched with wall motion impairment. These CMR findings in Takotsubo cardiomyopathy differ from those observed in acute coronary syndrome. Although the SPECT imaging improved considerably, DE remained in the chronic phase. The DE CMR finding is compatible with the pathological finding.