Kawasaki disease (KD) is a form of vasculitis affecting both the myocardium and coronary arteries. Coronary aneurysms develop in 15% to 25% of untreated patients (1,2). Myocardial inflammation is nearly universal during the acute phase (100% of cases in both post-mortem analysis and myocardial biopsy). However, there are no data about cardiac involvement during the convalescence of KD (1,2). Our aim was to evaluate the heart during the convalescence of KD by cardiac magnetic resonance (CMR). Thirteen KD patients, 6 to 8 years of age who fulfilled the currently used criteria for KD diagnosis, were evaluated by CMR 20 to 40 days after the onset of the disease. Patients were treated with high-dose immunoglobulin within the first 10 days of fever and responded well. Troponin I levels were normal in all except 1 patient, who had ST-segment elevation in II, III, and aVF. Patients were re-evaluated by CMR 3 months later.Coronary arteries were examined using a 3-dimensional segmented k-space gradient-echo sequence (echo time: 2.1 ms, repetition time: 7.5 ms, flip angle: 30°, slice thickness: 1.5 mm). Inflammation evaluation was performed using short tau inversion recovery T2-weighted analysis, early gadolinium enhancement (EGE), and late gadolinium enhancement (LGE) (contrast-enhanced fast spin echo T1-weighted magnetic resonance, flip angle: 15°, echo time: 1.4 ms, repetition time: 5.5 ms, inversion time: 225 to 275 ms as individually optimized to null myocardial signal). Left ventricular systolic function was evaluated using short-axis steady-state freeprecession sequence.The average length of continuously visualized left main coronary artery with left anterior descending coronary artery (LAD), left circumflex coronary artery, and right coronary artery (RCA) by magnetic resonance angiography was 5.2 Ϯ 0.8 cm, 4.2 Ϯ 1.0 cm, and 9.9 Ϯ 1.2 cm, respectively. The left circumflex coronary artery diameter was 2.01 Ϯ 0.17 mm, the LAD was 3.7 Ϯ 0.2 mm, and the RCA was 3.80 Ϯ 0.09 mm. Coronary artery ectasia (defined as diffuse, uniform luminal dilation between 1.50-to 2.0-fold larger than maximal normal diameter of the respective vessel [1]) was documented in all patients in the LAD and RCA, but not in the left circumflex coronary artery. Discrete, coronary aneurysms (defined as segmental dilation between 1.50-to 2.0-fold larger than maximal normal diameter of the respective vessel [1]) were assessed in 2 patients. An RCA aneurysm (5.5 mm in diameter and 9.5 mm in length) in 1 patient and a LAD