Integrated Backscatter，心筋シンチグラムにより経時的に評価しえた虚血性心疾患の1例

A Case Report Evaluating the Course of Ischemic Heart Disease, using Myocardial Integrated Ultrasonic Backscatter and Myocardial Scintigraphy

　虚血性心疾患症例のIBSのCV値，心筋シンチグラムを経時的に評価しえたので報告する．患者は77歳，女性，胸部圧迫感のため当科初診．心エコー図で後壁の壁厚増加率は低下，IBSのCV値は下後壁は低下し，BMIPP心筋SPECTでは下後壁の中等度から高度集積低下がみられ狭心症を疑った．初診15目後に胸痛が出現，緊急冠動脈造影では，右冠動脈のseg．1は完全閉塞で急性心筋梗塞と診断．PTCA，ステント留置により発症後2時間で再疎通した．発症10日後，IBSのCV値は上昇傾向，BMIPP心筋SPECTは下後壁は高度集積低下していた．発症34日後の冠動脈造影では，右冠動脈に再狭窄はなかった．発症50日後にIBSのCV値は正常化したが，心筋血流シンチグラムでは下壁の集積低下がみられた．心筋IBSのCV値は，虚血性心疾患の診断に有用とともに，急性心筋梗塞の再灌流成功例では早期に上昇し，viabilityの評価と治療効果の判定にも有用であった．

We report a case evaluating the course of ischemic heart disease using myocardial integrated ultrasonic backscatter (IBS) and myocardial scintigraphy. The patient was a 77-year-old female, who initially visited our hospital because of chest oppression. Echocardio-graphy showed decreased posterior wall thickening, and decreased cyclic variation (CV) of IBS in the infero-posterior wall. Myocardial scintigraphy using BMIPP demonstrated moderately to severely reduced uptake in the infero-posterior wall. A tentative diagnosis of an-gina pectoris was made. The patient had chest pain 15 days after the initial consultation, so she was examined by emergent coronary arteriography which showed the total occlusion of segment 1. A diagnosis of acutemyocardial infarction (AMI) was confirmed. She was treated with percutaneous transluminal angioplasty and stenting for segment 1, and revascularization was suc-cessful two hours after the onset of AMI. Ten days after the onset of AMI, although the CV of IBS was elevated in the infero-posterior wall, BMIPP myocardial SPECT showed severely reduced uptake in the infero-posterior wall. On the 34th day after the onset of AMI, coronary arteriography showed no restenosis of segment 1. Although the CVof IBS became normal in the infero-posterior wall 50 days after the onset of AMI, myocar-dial scintigraphy using a flow tracer showed moderately reduced uptake in the inferior wall. If revascularization is successful, the CV of IBS is elevated in the early stage. The CV of IBS is therefore useful for a diagnosis of ischemic heart disease and evaluation of myocardial viability.