MRAが有用と思われた冠動脈起始異常の2例

Magnetic Resonance Imaging (MRI) in the Diagnosis of Anomalous Origin of the Coronary Artery:Report of two cases

　冠動脈起始異常症は一般に冠動脈造影検査にて診断され，合併心奇形を伴わない場合も心筋梗塞や突然死の原因となることが報告されており，その予後の推定には冠動脈の走行の確認が必要である．今回，冠動脈起始異常症の2例にMagnetic Resonance Angiography（MRA）を施行し，その走行を確認することができた．症例1は回旋枝右冠動脈起始症で回旋枝は近位部のみ心エコー図でも描出されたが，末梢まで追うことは困難であった．症例2は右冠動脈左バルサルバ起始症で冠動脈は心エコー図では描出されなかった．MRAは三次元でのデータ収集や再構築が可能であるため，冠動脈の走行の評価に有用であると考えられた．

Anomalous origin of the coronary artery is usually diagnosed by conventional coronary angiography. This condition, without complication by other cardiac mal-formation, is known as a cause of myocardial infarction and sudden death. To estimate the prognosis of anoma-lous coronary arteries, it is necessary that we evaluate their anatomical course.

Magnetic resonance angiography (MRA) was perfor-med for two patients with anomalous origin of coronary arteries to delineate the course of these vessels. In case 1, the circumflex coronary artery arose from the right coronary cusp. The distal course of this artery was not visualized by echocardiography. In the second case, the right coronary artery originated from the left sinus of Valsalva, which is not detected by echocardiography. However these abnormal coronary arteries were identified by MRA.

Thus, MRA is a useful technique for noninvasive three-dimensional identification of the course of coro-nary arteries.