心筋梗塞症例における多方向心拍同期心プールスキャンによる局所壁運動異常の検出

Detection of regional wall motion abnormalities in the patients with myocardial infarction by multiple gated blood pool scan

　心拍同期心プールスキャンは，Strauss^1）らにより開発されて以来，虚血性心疾患を中心として，心機能，局所壁運動の評価に汎用されている^2）。しかし，心拍同期心プールスキャンは平衡相において施行するため，両心房，心室の多少の重なりは体位により避けられない。とくに，ファーストパス法において左室造影と同様の部位診断に関して有効な情報が得られる右前斜位30度（RAO 30°）は，両心室の重なりが著しい。

　そこで，著者らは，ルーチンに局所壁運動異常の検出に，左前斜位40度（LAO 40°），正面（ANT）および左後斜位30度（LPO 30°）の3方向から心拍同期心プールスキャンを施行している。

Regional wall motion abnormalities in the patients with myocardial infarction were evaluated by left lateral view (LLAT) and 30-degree left posterior oblique view (LPO) in addition to anterior view(ANT) and 45-degree left anterior oblique view (LAO)

There were 34 cases of anterior myocardial in-farction (ANT), 14 cases of infero-posterior myo-cardial infarction (IMI), 16 cases of antroinferior myocardial infarction and 16 cases of normal pa-tients. Each view was divided into five segments and regional wall motion score was assessed by semi-quantitative method (from normal= 1 to dy-skinesis=4). Infero-posteror wall motion abnorma-lities were demonstrated more clerly in LPO and/ or LLAT than in ANT. Detectability of IMI was improved from 58% in the conventional 2 (ANT, LAO) view to 81% in the 3 (ANT, LAO and LLAT) view and 77% in the 3 (ANT, LAO and LPO) view.

We concluded that the 3 (ANT, LAO and LPO) view should be performed in the gated blood pool scan to detect regional wall motion precisely.